To see the other types of publications on this topic, follow the link: Allophones in free variation.
Dissertations / Theses on the topic 'Allophones in free variation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Allophones in free variation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Gonzalez, Johnson Aracelis Maydee. "Dialectal Allophonic Variation in L2 Pronunciation." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/783.
Full textAbstract:
This thesis investigated the realization of the English voiceless post-alveolar affricate and the voiceless post-alveolar fricative in native Panamanian speakers learning English as a second language. The Spanish of Panama has a typical deaffrication process where the post-alveolar affricate phoneme is mostly pronounced as a fricative; as a result, the Spanish affricate has two allophones, the voiceless post-alveolar affricate and the voiceless post-alveolar fricative that occur in free variation in the Spanish of Panama. The word positions tested were word initially and finally only. Thus, the purpose of the study was to determine the dominant sound in the Spanish of Panama, to identify dialectal allophonic transfer from the Spanish of Panama, and to verify the accomplishment of the phonemic split in English through the frequency of usage of the target sounds. Subsequently, in order to exemplify the deaffrication phonological process of Panama, I developed and discussed a Feature Geometry of the Spanish language along with the Underspecified consonants of the Spanish language. In addition, I tested three main theories about acquisition of contrastive target sounds, Markedness, and similarity and dissimilarity of sounds. The results showed that these Panamanian learners of English produced the English voiceless post-alveolar fricative significantly more target appropriately than the English voiceless post-alveolar affricate. This indicates that the dominant sound in the Spanish of Panama is the dialectal allophone, the voiceless post-alveolar fricative, which I suggest may become the default post-alveolar phoneme in the Spanish of Panama. Subsequently, the high frequency of the voiceless post-alveolar fricative also indicates that the participants transferred their Panamanian Spanish dialectal allophone, the voiceless post-alveolar fricative, into English and more importantly, they have not reached the phonemic split for these two English target sounds. Taking the dialectal allophone, the voiceless post-alveolar fricative, as the default post-alveolar phoneme in the Spanish of Panama, The Markedness Differential Hypothesis (Eckman, 1977) accounts for the observed trends described as follows: the learning of the less marked sound (English voiceless post-alveolar fricative) was easier to acquire and the learning of the more marked sound (English voiceless post-alveolar affricate) was difficult to acquire.
2
Beaudoin, Sophie. "Attitudes d'enfants allophones et de leurs enseignants envers différens accents du français." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81479.
Full textAbstract:
The following thesis reports on an investigation of the attitudes of allophone children and their teachers towards different French accents. Using the matched guise technique, a total of 108 children in grades 4, 5 and 6 (5 groups) evaluated samples of French spoken with a standard accent, a standard Quebec accent, an informal Quebec accent and a foreign accent. The pupils evaluated the accents based on eight criteria related to linguistic, professional and personal characteristics. Secondly, sub-groups from each class participated in a post-experimental discussion about the accents they had heard. The children's teachers were also interviewed privately, in order to give their opinions about the accents, and share their vision of an oral model for these allophone children attending French language schools in Montreal. Findings suggest a strong preference for standard accents, which is confirmed by the analysis of the post-experimental discussions.
3
Raess, Michael. "Annual timing and life-history variation in free-living stonechats." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-63313.
Full text
4
Räss, Michael. "Annual timing and life-history variation in free-living stonechats." [S.l.] : [s.n.], 2005. http://edoc.ub.uni-muenchen.de/archive/00006331.
Full text
5
Parkinson, Steven. "Modelling free-surface flow with bathymetry variation using spectral methods." Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570859.
Full textAbstract:
Generation of electricity, by harnessing tidal currents with turbines, has the potential to contribute to a more sustainable future. However, knowledge of the fluid velocity, at a certain depth, is required in order to predict the available energy resource. Therefore, a modelling framework is described, which is computationally efficient, with only a few tunable parameters, and yields good results in comparison to experimental work and computational fluid dynamics. Existing approximate analysis methods, which describe fluid flow over varying topography are discussed. It is found that these theories are incapable of satisfying our objective. From field measurements of a tidal channel, a model is developed that describes turbulent free-surface flow over varying bathymetry. The flow is modelled using the steady incompressible two- dimensional shallow water equations. Turbulence closure is achieved using the eddy-viscosity model. The equations are solved using spectral methods. Convergence of the method is tested by varying the number of modes and the mixing parameterisation. A comparison with experimental work and a regional scale ocean circulation model, for free-surface flow over a ridge, is made. Close agreement is found using pseudo spectral methods. The Galerkin method does not achieve the same level of accuracy. In addition, numerical instability is found to occur on the downstream face of the ridge. However, provided the bathymetry gradients are sufficiently shallow, the solution procedure performs well. A three-dimensional model is achieved by calculating the two-dimensional depth-averaged flow through a tidal channel. Upon calculation of the streamlines from the depth-averaged flow solution, the vertical structure of the flow is calculated. The full flow profile can be obtained by piecing together outputs from each streamline. This is then compared to a one-dimensional hydraulic model where good agreement is found. Finally, flow for a real channel is computed.
6
Salazar, Israel. "Vocal Flexibility and Regional Variation in Free-Tailed Bat Song." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2602.
Full textAbstract:
While much work has been done on regional vocal variation in birds, relatively few studies have found evidence of similar variation in mammalian vocalizations. This study quantifies individual, colonial, and regional level variation in T. brasiliensis songs in the southeastern United States. Brazilian free-tailed bats (Tadarida brasiliensis) are among a handful of mammals that produce complex, hierarchically structured vocalizations. Their songs are composed of multiple syllables that are combined into three phrases that vary in number and order across renditions. Tadarida brasiliensis songs showed considerable amount of variation, and differed significantly between locations in terms of syllable structure and song syntax. Some of the variation observed was not correlated to geographical distance, and is unlikely to be explained by genetic divergence or differences in habitat use. These results indicate the existence of vocal dialects and a possible role of vocal production learning in dialect formation in this species.
7
Flint, Nicholas John. "A study of linewidth variation in the E.S.R. spectra of some radical anions." Thesis, Lancaster University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329999.
Full text
8
Ahiska, Bartu. "Reference-free identification of genetic variation in metagenomic sequence data using a probabilistic model." Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.561121.
Full textAbstract:
Microorganisms are an indispensable part of our ecosystem, yet the natural metabolic and ecological diversity of these organisms is poorly understood due to a historical reliance of microbiology on laboratory grown cultures. The awareness that this diversity cannot be studied by laboratory isolation, together with recent advances in low cost scalable sequencing technology, have enabled the foundation of culture-independent microbiology, or metagenomics. The study of environmental microbial samples with metagenomics has led to many advances, but a number of technological and methodological challenges still remain. A potentially diverse set of taxa may be represented in anyone environmental sample. Existing tools for representing the genetic composition of such samples sequenced with short-read data, and tools for identifying variation amongst them, are still in their infancy. This thesis makes the case that a new framework based on a joint-genome graph can constitute a powerful tool for representing and manipulating the joint genomes of population samples. I present the development of a collection of methods, called SCRAPS, to construct these efficient graphs in small communities without the availability or bias of a reference genome. A key novelty is that genetic variation is identified from the data structure using a probabilistic algorithm that can provide a measure of the confidence in each call. SCRAPS is first tested on simulated short read data for accuracy and efficiency. At least 95% of non-repetitive small-scale genetic variation with a minor allele read depth greater than 10x is correctly identified; the number false positives per conserved nucleotide is consistently better than 1 part in 333 x 103. SCRAPS is then applied to artificially pooled experimental datasets. As part of this study, SCRAPS is used to identify genetic variation in an epidemiological 11 sample Neisseria meningitidis dataset collected from the African meningitis belt". In total 14,000 sites of genetic variation are identified from 48 million Illumina/Solexa reads. The results clearly show the genetic differences between two waves of infection that has plagued northern Ghana and Burkina Faso.
9
Kanungo, Biraja Prasad. "Variation of free volume with deformation and relaxation for copper- and zirconium based bulk metallic glasses." Connect to this title online, 2004. http://www.ohiolink.edu/etd/view.cgi?osu1092922080.
Full textAbstract:
Thesis (M.S.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xiii, 115 p. ; also includes graphics (some col.). Includes bibliographical references (leaves 104-113). Available online via OhioLINK's ETD Center.
10
Sepil, Irem. "The secret in their MHC : variation and selection in a free living population of great tits." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:dd753cf0-9ec5-4d63-b318-57f037d73ee5.
Full textAbstract:
Understanding the genetic basis of fitness differences has been a major goal for evolutionary biologists over the last two decades. Although there are many studies investigating how natural selection can promote local adaptation, few have succeeded to find the link between genotype and fitness of the phenotype. Polymorphic genes of the major histocompatibility complex (Mhc) are excellent candidates for such associations as they are a central component of the vertebrate immune system, playing an important role in parasite resistance, and hence can have direct effects on survival of their bearers. Although associations between Mhc and disease resistance are frequently documented, the epidemiological basis of the host-parasite interaction is often lacking and few studies have investigated the role that Mhc genes play in individual variation in fitness; thus comparatively little is known about the fitness consequences of Mhc in wild populations. Furthermore, the majority of work to date has involved testing associations between Mhc genotypes and disease. However, the mechanism by which any direct selection on the Mhc acts, depends on how genotypes map to the functional properties of Mhc molecules. The aim of this thesis was to characterize Mhc alleles in terms of their predicted functional properties and to investigate whether and how selection operates on Mhc class I functional variation using the great tit (Parus major) population at Wytham Woods as a model host species. Through a comprehensive characterization effort and the use of 454 pyrosequencing platform, I performed a detailed analysis of genetic variation at Mhc class I exon 3 and grouped alleles with similar antigen-binding affinities into supertypes to classify functionally distinct Mhc types. There was extreme complexity at the Mhc class I of the great tit both in terms of allelic diversity and gene number. A total of 862 alleles were detected from 857 individuals; the highest number yet characterized in a wild bird species. The functional alleles were clustered into 17 supertypes; there was clear evidence that functional alleles were under strong balancing selection. To understand the role of Mhc in disease resistance, I examined the linkage between Mhc supertypes, Plasmodium infection and great tit survival, and showed that certain functional variants of Mhc confer resistance to two divergent Plasmodium parasite species that are common in the environment. I further investigated the fitness consequences of functional variation at Mhc, using mark-recapture methods and long-term breeding data; and tested the hypotheses that selection: (i) maximizes Mhc diversity; (ii) optimizes Mhc diversity, or (iii) favours specific functional variants. I found that the presence of three different supertypes was associated with three different components of individual fitness: adult survival, annual recruitment probabilities and lifetime reproductive success. In contrast, there was no evidence for a selective advantage of Mhc functional diversity, either in terms of maximal or optimal supertype diversity. Finally, I explored the role that Mhc plays in female mate choice decisions and examined the reproductive fitness consequences of Mhc-dependent mating patterns. There was little evidence to suggest that functional dissimilarity at Mhc has any influence on female mate choice decisions or that dissimilarity at Mhc affects the reproductive output of the social pair. Overall, this thesis provides strong support for the suggestion that selection favours specific functional variants of Mhc, possibly as a result of supertype-specific resistance or susceptibility to parasites that exert strong selective pressures on their hosts; whereas there is no support for selection favouring maximal or optimal Mhc diversity. More importantly it demonstrates that functional variants of Mhc class I loci are an important determinant of individual fitness in natural populations.
11
Mutzel, Ariane. "The role of parental care in shaping personality-related variation in reproductive success in free-living passerines." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-163919.
Full text
12
Dangol, Sharad. "Dynamic Response of Free-Standing Dry Storage Casks and Its Variation under Long Return Period Seismic Events." Thesis, The University of Utah, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10608698.
Full textAbstract:
Dry storage casks (DSCs) store spent nuclear fuel (SNF) at sites contiguous to nuclear power plants (NPPs), known as Interim Spent Fuel Storage Installations (ISFSIs). DSCs can be stored in concrete bunkers, or designed as free-standing or anchored structures. The primary focus of this study is to investigate response of free-standing DSCs under seismic excitation. Recent consideration of DSCs as a potential midterm solution may increase the operating period (initially 20 years) up to 300 years and requires response reevaluation. A longer compliance period results in larger accelerations, and larger vertical-to-horizontal spectral acceleration ratios that could have destabilizing effects on the cask response.
The response of free-standing DSCs under seismic excitations is highly nonlinear, especially under concurrent sliding and rocking motion triggered by multidirectional seismic excitations. It depends on parameters such as aspect ratio, coefficient of friction between cask and foundation pad, and ground motion characteristics, among other factors.
This research presents the investigation on the response of free-standing DSCs under long return period seismic events. Dynamic experimental tests were performed on a 6-degree-of-freedom shake table at the University of Nevada, Reno. Ground motions used for the tests were spectrally matched to spectral acceleration for seismic events of 10,000- and 30,000-year return periods. Experimental results were used to validate finite element (FE) models. The validated models were then be used to study casks’ response under full intensity long-term seismic event, tip-over spectrum under sinusoidal excitation and soil structure interaction (SSI).
The research also addresses whether the response of DSCs is repeatable under identical ground motions. If the cask response has a relatively large variation (nonrepeatable), the analytical and FE models cannot directly capture this variation. Experimental tests on repeated ground motions showed that the dynamic response is not repeatable, which is the first indicator of chaos or extreme sensitivity to initial conditions. Numerical techniques for chaotic analysis were then implemented, for harmonic excitation, to show that DSCs’ motion is in fact chaotic for certain excitation conditions. This sensitivity was studied in FE models and analytical simulations by varying input parameters by ±1%. This small change resulted in large variation in the response.
13
Ge, Chang. "The Seasonal Dynamics of Removal of Nitrogen in Free Water Surface Constructed Wetlands in cold climate." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-40816.
Full textAbstract:
In Sweden and other Nordic countries, Free Water Surface (FWS) constructed wetlands are widely used for advanced sewage treatment. This study was performed in an experimental wetlands system in order to research the seasonal dynamics and interferences in N removal under cold climate condition. According to the result of study, as expected, N removal in FWS wetlands is strong related to temperature, the removal rates are higher in late summer and autumn than in spring and early summer. Removal at similar temperatures are quite different when they are in different months. For instance, in the study, the average N removal in June is significant different from N removal in September (P＜0.001), indicating that there are other factors affecting the N removal, different treatment wetlands have different situations. N removal in two different periods (March to July & August to December) were extracted for covariance analysis, it indicated that they are significant different. Besides that, the r2-value of correlation test showed that total N removal rate in FWS constructed wetlands is higher in relation to temperature in autumn and winter (r2-value is 0.4449) than in spring and summer (r2-value is 0.3857). Generally speaking, the dynamics of N removal in FWS wetlands is not steady and variable even at similar temperatures. Finally, I find the temperature of excess heating from district heating which has been used by the residents’ house in Sweden is high enough to heat up the temperature in FWS wetlands. That is a valuable improvement to be put forward.
14
Rabab'ah, Samer Rateb. "INTEGRATED ASSESSMENT OF FREE DRAINING BASE AND SUBBASE MATERIALS UNDER FLEXIBLE PAVEMENT." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1189128048.
Full text
15
Prinsloo, HC, V. Harley, BK Reilly, and TM Crowe. "Sex-related variation in morphology of helmeted guineafowl (Numida meleagris) from the Riemland of the northeastern Free State, South Africa." South African Journal of Wildlife Research, 2005. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001002.
Full textAbstract:
In the hope of developing a relatively simple, nondestructive
way of sexing adult helmeted guineafowl
(Numida meleagris ), sexual differences in body
mass and in the size of head adornments of adult
helmeted guineafowl sampled during the winter
months in the Riemland district of the northeastern
Free State, South Africa, were investigated. Males
have statistically significantly larger values for all
attributes than do females. However, no single
attribute, nor a combination of them, can be used to
sex guineafowl unambiguously.
16
Nasser-Barakat, Fatima. "Automatic modal variation tracking via a filter-free random decrement technique application to ambient vibration recordings on high-rise buildings." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT044/document.
Full textAbstract:
Cette thèse propose une nouvelle approche pour surveiller automatiquementles variations des fréquences et des taux d’amortissement des batiments de grande hauteursoumis à des vibrations ambiantes. L’approche vise à relever simultanément avec les défissuivants: signaux multi-composants enregistrées sur les bâtiments mentionnés ci-dessusavec des réponses impulsionnelles ayant des modes de fréquences rapprochées, des amplitudesfaibles, exponentielles et amorties noyées dans des bruits additifs élevés. La méthoderepose sur l’application de la technique de décrément aléatoire directement sur le signal multicomposantece qui conduit à l’estimation d’une signature de décrément aléatoire multi-modeéquivalente à la réponse impulsionnelle de système. Pour caractériser une telle signature,nous proposons un modèle de signal basé sur la structure physique du bâtiment à partir delaquelle les paramètres modaux peuvent être estimés. Dans le but d’avoir une estimationnon biaisée, nous proposons d’utiliser une méthode itérative sur la base d’une estimation dumaximum de vraisemblance optimisé par une technique de recuit simulé. Afin d’initialiserles paramètres de ce dernier, une première étape est conçu qui peut être considéré commeun estimateur indépendant des paramètres modaux. L’originalité de cette étape réside danssa capacité à définir automatiquement le nombre de modes de la signature estimé grâce àl’utilisation des propriétés statistiques d’un spectre estimé par une transformée de Fourier.Les paramètres modaux estimés par l’étape d’initialisation sont finalement affinés par l’étaped’estimation du maximum de vraisemblance. Celui-ci réduit le biais de l’estimation et donnedes résultats plus fiables et plus robustes. Toutes ces étapes sont définies de manière à être enmesure de surveiller automatiquement l’état de santé d’un bâtiment par l’intermédiaire d’unsuivi long terme en temps réel des variations modales dans le temps sans que l’interventionde l’utilisateur soit nécessaire. En outre, l’approche proposée a accordé une attention touteparticulière à l’estimation automatique du paramètre modal les plus problématique, c’està-dire, le taux d’amortissement. Ces deux caractéristiques sont des atouts originaux parrapport aux techniques existantes. L’adaptabilité et la fonctionnalité de l’AMBA a été validésur six bâtiments réels excités par des vibrations ambiantes. D’après les résultats obtenus,AMBA a prouvé une grande efficacité dans l’estimation automatique des fréquences et destaux d’amortissement dans le cas de modes de fréquences rapprochées et avec un très faiblerapport signal-sur-bruit. AMBA a ainsi démontré une bonne performance pour suivre lesvariations modales au fil du tempsThis thesis proposes a novel approach to automatically monitor the variationsof the frequencies and the damping ratios of actual high-rise buildings subjected to realworldambient vibrations. The approach aims at dealing simultaneously with the followingchallenges: multi-component signals recorded over the aforementioned buildings and havingclosely-spaced frequency modes with low, exponential and damped amplitudes of theirimpulse responses and contaminated with high additive noises. The approach relies on theapplication of the Random Decrement Technique directly over the multi-component signalunder study which leads to the extraction of a Multi-mode Random Decrement Signatureequivalent to the system impulse response. To characterize such a signature, we propose asignal model based on the physical structure of the building from where the modal parameterscan be estimated. For the purpose of non-biased modal estimate, we propose to usean iterative method based on a Maximum-Likelihood Estimation optimized by a simulatedannealing technique. In order to initialize the parameters of the latter, a first step is designedwhich can be considered as an independent estimator of the modal parameters. Theoriginality of this step lies in its ability to automatically define the number of modes of theestimated signature through the use of the statistical properties of a Welch spectrum. Themodal parameters estimated by the spectral-based initialization step are finally refined bythe Maximum-Likelihood Estimation step. The latter reduces the bias in the estimation andyields more reliable and robust results. All these steps are defined in order to be able to automaticallymonitor the health of a building via a long-term real-time tracking of the modalvariations over time without the need to any user intervention . In addition, the proposedapproach has paid very special attention to the automatic estimation of the most problematicmodal parameter, i.e., the damping ratio. Such features making two of the original featuresas compared to existing techniques. The adaptability and functionality of AMBA is validatedover six actual buildings excited by real-world ambient vibrations. From the obtained results,AMBA proved high efficiency in automatically estimating the frequencies and moreover thedamping ratios in case of closely-spaced frequency modes and very low signal-to-noise ratiolevel. AMBA as well demonstrated a good performance for tracking the modal variationsover time
17
Pandey, Bishnu Hari. "Investigation of variation of motions between free field and foundation in seismic soil-structure interaction of structures with rigid shallow foundation." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45172.
Full textAbstract:
Soil-foundation-structure interaction (SFSI) in buildings during earthquakes is characterized by several aspects including the variation between the free-field and foundation motions. Past procedures for analysing the effect of the foundation on the free-field input motions are all based on the assumptions that the foundation slabs always reduce the motion. Recent guidelines, standard and codes including FEMA-440 and ASCE/SEI41-06 also recognize that foundations with interconnected grade beams or concrete slab will always reduce the free-field motions. It implies that SFSI is beneficial and can be conservatively neglected in regular building design practice. A large number of instrumented buildings that have experienced a numbers of earthquakes in the past provide an opportunity to investigate the SFSI effects and evaluate the methods of estimating the foundation motion based on field data.
In this research study, investigation is carried out on the records of past earthquakes from sites of instrumented buildings over a wide range foundation configurations and site conditions in California. Analysis of records among 26 buildings that have shallow rigid foundation shows that foundation motions are reduced in two-third cases and amplified in one-third cases. The estimations of variation of motion by the ASCE procedure are not in good agreement, even for the cases of reduction of foundation-base motion. It was obvious that the amplification of the motion cannot be captured by the procedure.
Time history simulations of soil-building system have been carried out for varied parameters in 2D continuum finite element models using computer program ABAQUS. The results from simulations confirm that motion may amplify at the foundation depending on period of the building, soil deposit and the predominant period of input motion.
This thesis develops a simple mass–spring–dashpot-based system of soil–foundation–structure interaction, called the 3DOF SFS model, for calculating the foundation-base motion that accounts for dynamic interaction between soil, foundation and building. The 3DOF SFS model was verified for a building-structure system with varied parameters and for different input motions using results from ABAQUS. Both amplification and reduction cases of foundation motion compared with free field were predicted by the model.
18
Mutzel, Ariane [Verfasser], and Niels [Akademischer Betreuer] Dingemanse. "The role of parental care in shaping personality-related variation in reproductive success in free-living passerines / Ariane Mutzel. Betreuer: Niels Dingemanse." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1047062259/34.
Full text
19
Loës, Corinna [Verfasser], and Bart [Akademischer Betreuer] Kempenaers. "Variation in sleep behaviour and its underlying causes : a study in a free-living blue tit population / Corinna Loës. Betreuer: Bart Kempenaers." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1031379371/34.
Full text
20
Austin, Alice Ann keyl. "Evaluating the Effects of Reinforcer Choice and Reinforcer Variation on the Response Rates of Children with Autism." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1014.
Full textAbstract:
Motivating individuals with autism can be challenging for clinicians and educators seeking to increase skills or decrease problem behaviors. Even when highly preferred reinforcers have been identified, they tend to lose their effectiveness over time. Over the years, several strategies have been developed to maintain the effectiveness of reinforcers. Reinforcer variation has been demonstrated to attenuate decreases in responding associated with repeated exposure to a single reinforcer. Another strategy that has been used to help maintain responding is allowing an individual a choice among reinforcers. Several researchers have suggested that providing choice among several reinforcers may produce the same effects on responding as reinforcer variation. Although these two procedures have been shown to maintain motivation in individuals with autism, they have not been systematically compared and evaluated against each other. In this study, we evaluated the effects of reinforcer variation as compared to reinforcer choice.
21
Pouchkova, Meyer Svetlana. "Vers un dictionnaire des mots à Charge Culturelle Partagée comme voie d'accès à une culture étrangère (FLE) : le cas des apprenants immigrés adultes multiculturels." Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/POUCHKOVA_MEYER_Svetlana_2010.pdf.
Full textAbstract:
La culture comportementale du plus grand nombre ne parvient pas à se faire reconnaitre et à s'imposer auprès de la culture savante d'une minorité. Cette culture est appelée par R. GALISSON « partagée» parce que l'immense majorité des natifs la maitrisent. Elle n'est enseignée nulle part, mais acquise, hors de l'école, au cours des événements quotidiens. Cependant, elle est essentielle parce qu'elle sert à la fois: De signe de reconnaissance tacite entre tous les individus qui se réclament de la même identité collective ; De modèle de conditionnement dans les situations grégaires de la vie courante ; D'ingrédient de convivialité, c'est-à-dire de commun dénominateur pour mieux se comprendre et s'accepter. Si cette culture primordiale est acquise par les locuteurs natifs, elle pourrait être apprise par les apprenants étrangers, donc décrite, et enseignée en cours de FLE. Et ce à travers l'étude de certains mots, nommés les mots à Charge Culturelle Partagée où elle se dépose avec prédilection. Ces mots pourraient être inventoriés, définis et consignés dans un dictionnaire dit de culture partagée. Ainsi ce dictionnaire aurait pour objet est de rendre compréhensible à des apprenants étrangers le discours et le comportement général des locuteurs natifs françaisThe culture of comportment of the majority can 't try to get the confession in the society side by side with the scientific culture. The French linguist R. GALISSON called this culture as "generally accepted", so the majority bearers of language posses il. It is nowhere studied, it is taken outside of school during the process of the daily life. Nevertheless, it is very important because it indicates at the same time: The sign of identify between people who rank themselves among the same society; The model of socio- cultural comportment (the conditional model) in the daily life's situations; The sign of benevolence or, in the other words, the common denominator for the best comprehension and tolerance. If this the most important culture is acquired by the bearers of language during the everyday life, it can be described and studied by the foreign students at the French lessons. Lt takes place thanks to the specific words which carry the vast layer of the "generally accepted" culture. These words must be defioed and entered in the special cultural dictionary, the purpose of which is to facilitate the perception of the socio- cultural component in the discourse and the comportment of the bearers oflanguage for the foreign students
22
Sung, Young-Hee. "Le rôle de l'inter-/trans-culturel dans la compréhension de l'inférence discursive chez les apprenants coréens du FLE." Strasbourg, 2009. http://www.theses.fr/2009STRA1049.
Full textAbstract:
L’inférence en tant qu’une activité associée au fonctionnement du raisonnement est employée, à l’origine, dans la logique formelle pour décrire les rapports de vérité existant entre différentes propositions. Par ailleurs, nous savons bien que les faits de langage sont soumis à des conditions de vérité sans que cela ne les réduisent tous à une description strictement logique. Il est donc nécessaire de tenir compte de la situation empirique dans laquelle ces manifestations langagières sont produites et interprétées. Globalement, on peut donc considérer l’inférence comme un acte de langage dont l’accomplissement implique la production d’un énoncé. Il est vrai que lorsque l’on côtoie une langue et une culture, on oublie vite qu’au-delà des éléments formels du système linguistique, c’est d’abord le langage, c’est-à-dire l’expression particulière d’une ou de plusieurs langue telle qu’elle est comprise par des sujets concrets, situés qui est traduite comme une pratique sociale. Par conséquent, il nous semble important de réaffirmer que l’inférence est l’une des unités structurants les plus à même de rendre compte à la fois du langage, de la logique rhétorique et du linguistique en tant que pratique sociale d’abord. Certaines formes de l’ inférence telle qu’elle est utilisée dans la langue-culture française ainsi que dans les formes qu’elle revêt en langue-culture coréenne nous paru être des phénomènes intéressants pour servir de tiers-actant dans les manifestations du langage, du linguistique et de la transculturalitéThe inference as an activity associated with the operation of reasoning is used, initially, in formal logic to describe the relationship between truth proposals. We also know that the facts of language are subject to the conditions of truth but this does reduce all to a strictly logical description. It is therefore necessary to consider the empirical situation in which language these events are produced and interpreted. Overall, one can consider the inference as an act of language that the performance involves the production of an utterance. It is true that when one meets a language and culture, we forget that beyond the formal elements of the language system is first language, i. E. The particular expression one or more language as understood by concrete subjects, which is located, translated as a social practice. Therefore, it is important to reiterate that the inference is one of the structural units most likely to report at once the language, rhetoric and logic of language as social practice first. Some forms of the inference as used in the French language and culture in the forms it takes in Korean language and culture we seemed to be interesting phenomena to serve as third-Taking in the events of language of linguistics and transculturality
23
Merlo, Jonathan-Olivier. "Diatopie et représentations linguistiques des enseignants de langue étrangère : regards croisés sur les enseignants de français en Italie et au Tessin et les enseignants d’italien en Belgique francophone, France et Suisse romande." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAL004/document.
Full textAbstract:
Quelle place accorder à la variation, en particulier diatopique, dans l’enseignement / apprentissage de la L2 ? Malgré une réflexion abondante et de longue date en Français langue étrangère, ou plus discrète en Italiano lingua straniera, l’introduction d’un discours variationnel de type sociolinguistique en classe de L2 reste encore aujourd’hui un exercice délicat, d’autant que l’évocation de la diatopie est un excellent déclencheur des opinions et des stéréotypes sur la langue. Partant de la notion de communauté linguistique comme communauté de normes partagées par l’ensemble des membres, on a considéré 3 types de contextes sociolinguistiques : 1. l’espace français, fortement monocentrique, et dont le modèle de langue largement diffus à travers l’Hexagone tend à la neutralité du point de vue diatopique, 2. l’espace francophone européen, hors Hexagone, en marge de la langue mais dans lequel on assiste malgré tout à l’émergence récente d’un lent phénomène d’auto-légitimation des communautés francophones périphériques, 3. l’Italie et le Tessin, puisque cette même dimension diatopique y constitue la toile de fond de l’italien contemporain et qu’elle est omniprésente dans les pratiques langagières de tout locuteur. Sachant que l’institution scolaire est le principal agent de reproduction, de diffusion et de reélaboration constante de l’idéologie linguistique du standard et de l’unilinguisme, on a voulu enquêter en direction des attitudes et des opinions des enseignants d’ILS en contexte francophone européen et de leurs collègues de FLE en contexte italophone. Un questionnaire a été réalisé en deux langues et a fait l’objet entre 2013 et 2014 d’une diffusion en ligne systématique auprès de tous les établissements scolaires de niveau équivalent lycée – gymnases, athénées, scuole superiori, etc. – de Belgique francophone, de France, de Suisse romande, d’Italie et du Canton du Tessin. Cette enquête, à laquelle plus de 1100 enseignants de FLE et d’ILS ont participé, a fourni un grand nombre de données ayant requis une analyse plusieurs étapes.On a d’abord pu comprendre dans quelle mesure l’appartenance de l’enseignant à un contexte sociolinguistique plus ou moins ouvert à la diatopie est susceptible d’influencer sa perception de cette variation et de ses propres pratiques didactiques. Ensuite, les informations recueillies nous ont permis de mieux appréhender la dialectique existant, au sein de l’imaginaire linguistique de la profession, entre vécu langagier individuel et adhésion à l’idéologie linguistique dominante du standard. Enfin, l’analyse et la confrontation des données quantitatives et textuelles ont permis de mettre finalement en évidence que les enseignants des différents contextes sociolinguistiques considérés partagent des représentations linguistiques tout à fait semblables mais surtout un seul et même imaginaire professionnelQuale ruolo dare alla variazione, in particolare diatopica, nell’insegnamento / apprendimento della L2 ? Malgrado una riflessione abbondante e pluridecennale in Français langue étrangère o più discreta in Italiano lingua straniera, l’introduzione del discorso variazionale di tipo sociolinguistico in classe di L2 rimane a tutt’oggi assai delicata, tanto più che accennare alla diatopia permette di fatti di innescare dibattiti nei quali osservare opinioni e stereotipi sulla lingua. Partendo dalla nozione di comunità linguistica intesa come comunità di norme condivise da tutti i membri, abbiamo considerato 3 tipi di contesti sociolinguistici: 1. lo spazio francese, fortement monocentrico, il cui modello di lingua largamente diffuso all’interno dei confini dello Stato tende alla neutralità dal punto di vista diatopico; 2. lo spazio francofono europeo, fuori dalla Francia, ai margini della lingua sebbene vi si possa osservare in tempi recenti l’emergere di un lento fenomeno di auto-legittimazione delle comunità francofone periferiche; 3. l’Italia e il Ticino, dove la dimensione diatopica fa da sfondo al continuum dell’italiano contemporaneo ed è omnipresente negli usi linguistici quotidiani dei parlanti.Considerato che l’istituzione scolastica è il principale agente di riproduzione, diffusione e rielaborazione costante dell’ideologia dello standard e dell’unilinguisme, abbiamo voluto indagare in direzione degli atteggiamenti e delle opinioni degli insegnanti d’ILS in contesto francofono europeo e dei loro colleghi insegnanti di FLE in contesto italofono.Un questionario realizzato in due lingue è stato diffuso online tra il 2013 e il 2014 presso tutte le scuole superiori o di livello equivalente – gymnases, athénées, lycées, etc. – del Belgio francofono, di Francia, della Svizzera francofona, d’Italia e del Cantone del Ticino. Questa inchiesta, alla quale più di 1100 insegnanti di FLE e di ILS hanno partecipato, ha permesso di raccogliere un gran numero di dati che hanno necessitato un’analisi in più tappe.Abbiamo potuto in primo luogo cogliere in quale misura l’appartenenza dell’insegnante ad un contesto sociolinguistico più o meno aperto alla diatopia è suscettibile di influenzare la sua percezione di questa variazione e delle proprie abitudini didattiche. Poi, le informazioni raccolte ci hanno consentito di meglio capire la dialettica che esiste, all’interno dell’immaginario linguistico della professione, tra vissuto linguistico individuale e adesione all’ideologia linguistica dominante dello standard. Infine, l’analisi ed il confronto dei dati quantitativi e testuali hanno permesso di mettere finalmente in evidenza il fatto che gli insegnanti dei differenti contesti sociolinguistici presi in considerazione condividono delle rappresentazioni linguistiche del tutto simili ma soprattutto un solo e unico immaginario professionale
24
Viana, dos Santos Gabriela. "Représentations et schémas sociolinguistiques en langue étrangère : l'exemple d'apprenants sinophones et anglophones du FLE." Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALL003.
Full textAbstract:
L’une des particularités du processus d’acquisition sociolinguistique en langue étrangère porte sur la difficulté des apprenants à intégrer les normes sociolinguistiques de la langue cible. Si dans leur culture native, les apprenants construisent un réseau d’associations entre connaissances linguistiques et connaissances sociales, en langue étrangère ils doivent développer cette capacité. Notre préoccupation centrale dans ce travail était de comprendre d’une part si les apprenants développent des schémas qui associent des variantes sociolinguistiques avec des paramètres sociaux et d’autre part quelles valeurs socio-indexicales des apprenants attribuent aux variétés. Nous avons donc mené deux études auprès d’apprenants de FLE en séjour d’étude en France. Pour la première étude, nous avons fait passer une tâche de répétition auprès de 24 étudiants anglophones et de 42 étudiants sinophones. La deuxième étude, un test de réaction subjective, a été menée auprès de 40 étudiants anglophones, de 41 étudiants sinophones et de 88 francophones natifs. Notre analyse met en évidence la tendance des apprenants à rendre homogènes des énoncés non homogènes sur le plan sociolinguistique. Ce résultat suggère que les apprenants construisent des schémas sociolinguistiques des variétés standard et non standard en langue étrangère. Nous avons également constaté que les apprenants sont sensibles aux variations sociolinguistiques en langue cible. En effet, ils ont jugé de façon différente des énoncés standard et non standard du français. En outre, notre analyse fait émerger des différences dans la construction des schémas sociolinguistiques et dans les jugements des variétés entre les deux nationalités de notre étudeOne of the particularities of the process of sociolinguistic acquisition in a foreign language concerns the difficulty of learners to integrate the sociolinguistic norms of the target language. If in their native culture, the learners build a network of associations between linguistic knowledge and social knowledge, in a foreign language, they must develop this capacity. The main objectives of this work are to understand how learners develop schemas that associate sociolinguistic variants with social parameters and how they associate socio-indexical values to varieties. We carried out two studies with FLE learners studying in France. For the first study, we did a repetition task with 24 English-speaking students and 42 Chinese-speaking students. The second study, a subjective reaction test, was conducted among 40 English-speaking students, 41 Chinese-speaking students, and 88 native French-speaking students. Our analysis highlights the tendency of learners to make homogeneous statements that are not homogeneous at the sociolinguistic level. This result suggests that learners construct sociolinguistic schemas of standard and non-standard varieties in a foreign language. We have also found that learners are sensitive to sociolinguistic variations in the target language. Indeed, they judged standard and non-standard French statements differently. Our analysis also reveals differences in the construction of sociolinguistic schemas and in the judgments of varieties between the two nationalities of our study
25
Abouelgamal, Tarek. "Enseigner l’insaisissable : la diglossie didactique ou comment la dépasser : étude d’un corpus de manuels/grammaires d’arabe égyptien et littéral." Thesis, Sorbonne université, 2020. http://accesdistant.sorbonne-universite.fr/login?url=http://theses.paris-sorbonne.fr/2020SORUL063.pdf.
Full textAbstract:
Il est d’usage dans les milieux universitaires arabisants de présenter l’arabe comme étant en situation de diglossie quels que soient les débats ultérieurs venus raffiner ce concept-clé. Or, la diglossie a une origine ; elle a aussi des applications concrètes. Elle a impliqué une séparation artificielle dans les méthodes d’enseignement de l’arabe. Nous interrogeons dans notre présent travail le support pédagogique et son rôle dans la fabrication et dans l’énonciation du contenu relevant de la variété dialectale. La première partie de notre travail examine l’histoire des manuels d’arabe en Europe en mettant l’accent sur le contexte dans lequel ils ont été publiés mais aussi sur l’analyse qu’ils faisaient de la question de la variété linguistique. La seconde partie analyse le contenu d’un corpus de manuels du dialecte égyptien (de 1965 jusqu’à 2016) à la recherche d’un socle commun enseignable pour la variété dialectale. Nous examinons le contenu structurel (phonèmes, types de phrase, système verbal, etc.), communicatif (actes de parole) et culturelIt is customary among Arabists to describe the sociolinguistic situation of Arabic as diglossic. However, diglossia has its origins; it also has its concrete applications. To give a hint, diglossia entails an artificial distinction between MSA classrooms and colloquial ones, each has its proper teaching materials and its syllabus. My intent here is to analyse a large number of Arabic textbooks to find out how this corpus creates a linguistic variety which, in a sense, does not exist in the natives’ daily usage. The first part of my study explores the history of Arabic textbooks from the 16th to the 19th century in Europe. I focus on the circumstances in which these books were published and also on the conception that different authors have. I furthermore try to find out whether these books were affiliated to a Greco-Latin grammatical paradigm or an Arabic one. The second part of my study describes and analyses the structural-pragmatic-cultural content of twelve Egyptian colloquial textbooks published between 1965 and 2016 looking into their “common core”. Our argument is that, the diglossia still the hegemonic framework in the classrooms (What I shall call a “diglossic teaching”). Other theories such as continuum are marginalised nowadays in France. However, the history of textbooks (particularly the Savary case) proves that the diglossic paradigm is not a pedagogical fate
26
Egydio, Anary Priscila Monteiro. "Análises das variações fitoquímicas, estruturas genética e importância econômica de Annona crassiflora Mart., no cerrado." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-21052009-103822/.
Full textAbstract:
A Annona crassiflora Mart. é uma espécie frutífera nativa do cerrado que possui alto potencial de uso e ampla distribuição. O presente trabalho tem os seguintes objetivos: identificar e quantificar aminoácidos livres, carboidratos solúveis e ácidos graxos da polpa e das sementes, visando ampliar os conhecimentos sobre potencial econômico de A. crassiflora; avaliar qual o nível de variações quantitativas e qualitativas de alcalóides de A. crassiflora de amostras provenientes de diferentes regiões do cerrado; avaliar qual a magnitude da diversidade genética entre diferentes populações de A. crassiflora, utilizando marcadores isoenzimáticos. Com relação às propriedades nutricionais, as análises de aminoácidos livres, carboidratos e lipídeos foram feitas por CLAE/F, por CLAE/CTI - DPA e por CG/EM, respectivamente. O teor total de aminoácidos livres na polpa variou de 1101,99 g/g a 1975,7 g/g de massa seca, enquanto nas sementes variou de 636,3 μg/g a 17.445,83 μg/g de massa seca. A glutamina foi majoritária em todas as amostras. O teor total dos carboidratos solúveis da polpa variou de 11,5 g/100g a 17,03 g/100g e das sementes variou de 13,69 g/100g a 40,47 g/100g de matéria seca. Foram detectadas a frutose, a glicose e a sacarose em todas as amostras de polpa e de sementes. A quantidade de lipídeos totais da polpa variou de 7g/100g a 16,2 g/100g de massa seca e das sementes variou de 34,36 g/100g a 35,98 g/100g de massa seca. O ácido oléico e/ou petroselínico (18:1) foram majoritários em todas as amostras de polpa e de sementes de diferentes origens geográficas. Certamente os dados obtidos permitiram ampliar os conhecimentos sobre potencial de aproveitamento dessa espécie. Para avaliar a magnitude da variação dos alcalóides das folhas de A. crassiflora, a quantificação e identificação dos alcalóides foram feitas, respectivamente, por CG/FID e CG/EM. Foi verificado que o teor total de alcalóides variou de 221,1 ± 17,14 μg/g a 2986,89 ± 367,1 μg/g de massa seca. Foram identificados os alcalóides anonaína, anoretina, romucosina e xilopina que mostraram diferenças entre as regiões. Essa variação na concentração e no perfil alcaloídico das populações de A. crassiflora sugere ampla plasticidade fenotípica desses metabólitos em resposta a fatores bióticos e/ou abióticos, além de alta variabilidade genética relacionada à expressão dos genes envolvidos na biossíntese desses metabólitos. A avaliação da estrutura genética foi feita através da análise isoenzimática. Os dados isoenzimáticos mostraram baixa variabilidade genética. Duas hipóteses são apontadas para explicar o baixo nível de polimorfismos verificado em A. crassiflora, uma delas relacionada à técnica e outra relacionada ao próprio processo de degradação do ambiente. Diante do exposto, os dados obtidos no presente trabalho sugerem formas de agregar mais valor econômico e ecológico à A. crassiflora e podem proporcionar uma base para o uso mais eficiente e racional dos recursos dessa espécie, contribuindo para exploração sustentável do cerrado, o que permite também o desenvolvimento de comunidades locais.Annona crassiflora Mart. is a native fruit tree species from the cerrado, possessing high use potential and a wide distribution. The proposed aims were to identify and quantify free amino acids, free sugars and fatty acids in the pulp and seeds of this plant, with a view to widening knowledge on economical potentiality, as well as to evaluate the level of alkaloid quantitative and qualitative variation in samples coming from different regions of the cerrado, and finally define the size of genetic diversity among these different populations by using isoenzymatic markers. As to nutritional properties, analyses of free amino acids, free sugars and fatty acids were undertaken with, respectively, CLAE/F, CLAE/CTI DPA and CG/MS. The total rate of free amino acids in the pulp varied from 1101,99 ug/g to 1975,7 ug/g of dry mass, whereas in the seeds this variation was from 636,3 μg/g to 17.445,83 μg/g. Glutamin was preponderant in all the samples. Total free sugar rate in pulp varied from 11,5 g/100g to 17,03 g/100g and in seeds from 13,69 g/100g to 40,47 g/100g of dry matter. Fructose, glucose and sacarose was detected in all samples. The amount of total lipids in pulp varied from 7 g/100g to 16,2 g/100g of dry weight and in seeds from 34,36 g/100g to 35,98 g/100g. Oleic and/or petroselinic acids (18:1) were the most abundant in all pulp and seed samples from the different geographic regions. The obtained results certainly permit widening knowledge on the potentiality for use of this plant species. In order to evaluate the size of alkaloid variation in A. crassiflora leaves, alkaloid quantification and identification was done with, respectively, CG/FID and and CG/EIMS. It was noted that the total alkaloid rate varied from 221,1 ± 17,14 ug/g to 2986,89 ± 367,1 μg/g of dry mass. The alkaloids anonain, anoretin, romucosin and xilopin were identified, these showing differences among regions. This variation in alkaloid concentration and profile in A. crassiflora populations suggests the wide phenotypic plasticity of these metabolites in response to biotic and/or abiotic factors, besides high genetic variability related to gene expression of those involved in their biosythesis. Genetic structure evaluation was done through isoenzymatic analysis. Isoenzymatic data revealed low genetic variability. Two hypotheses may be raised to explain this low polymorphism level. The first points to inefficient isoenzymatic techniques in reckoning species genetic diversity, whereas the second takes into consideration that excessive homozygosis (indicated by the low level of isoenzymatic variability) could be an indication of the process of species genetic erosion, possibly related to habitat (cerrado) degradation. In view of this, data obtained in the present study suggest forms of aggregating additional economical and ecological value to A. crassiflora, and could furnish a base for the more efficient and rational use of resources from this species, thus contributing to sustainable exploitation of the cerrado, and also allowing for local community development.
27
Riou, Etienne. "La dislocation clitique à gauche en français langue étrangère." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC104/document.
Full textAbstract:
Cette thèse s’intéresse à la description didactique de la variation linguistique dans une approche à contraintes. En nous appuyant sur la Troisième Vague de l’étude de la variation (Eckert, 2012) et les Social Meaning Games (Burnett, 2017 ; sous presse), nous postulons que les contraintes stylistiques sont un sous-ensemble de contraintes pragmatiques. Cette approche nous permet d’envisager la variation dans une perspective fonctionnelle plutôt que normative et de décrire les variantes « non-standard » comme plus ou moins appropriées à une tâche plutôt que comme des déviations de la norme. Pour illustrer notre approche, nous l’appliquons à la description de la dislocation clitique à gauche en français. Nous proposons que la variation de la dislocation clitique à gauche avec les clivées et les constructions canoniques est contraintes par la structure informationnelle (Lambrecht, 1994), les relation d’ensembles partiellement ordonnés (Ward & Birner, 1991) et une stigmatisation stylistique dans les contextes formels (Zribi-Hertz, 1994). Nous suggérons que ces contraintes sont toutes de nature pragmatique et que leur interaction influe sur l’emploi de la dislocation clitique à gauche en français. Ces hypothèses sont testées empiriquement via une étude de corpus, une série de test de jugements d’acceptabilité et un test de Matched Guise. De plus, nous postulons que l’apprentissage des contraintes pragmatiques en langue étrangère dépend de leur enseignement explicite et l’exposition répétée à la construction dans des contextes acceptables. Suivant l’hypothèse de l’interface dynamique (Ellis, 2005), nous suggérons que l’apprentissage explicite des contraintes de la dislocation clitique à gauche dans le contexte de la classe de langue facilite leur apprentissage implicite lorsque les apprenant se retrouve dans une situation de communication avec des locuteurs natifs du français. Le rôle de l’exposition est exploré empiriquement en répliquant un test de jugements d’acceptabilité et le test de Matched Guise avec des participants non-natifs. Enfin, nos observations sont implémentées dans le discours didactique à l’aide de notions et d’une terminologie déjà employés dans les grammaires pédagogiques (Germain & Séguin, 1998). Les contraintes discursives de la dislocation clitique à gauche sont décrites via la distinction entre informations familières et nouvelles (Capelle & Gidon, 1999 ; Watorek, 1998). Les contraintes stylistiques sont décrites via la compétence de savoir-être et les registres sociolinguistiques (CECR, 2001)The present dissertation deals with didactic description of linguistic variation in a constraint-based approach. In line with the Third Wave movement of variation studies (Eckert, 2012) and Social Meaning Games (Burnett, 2017; accepted), we argue that stylistic constraints are a subset of pragmatic constraints. This approach allows us to consider variation in a functional perspective rather than in a normative perspective and to describe “non-standard” variants as more or less appropriate to certain tasks rather than deviations from the norm. To illustrate our approach, we are applying it to the description of clitic left dislocation in French. We propose that the variation of clitic left dislocation with clefts and canonical construction is constrained by information structure (Lambrecht, 1994), Partially Ordered Set relations (Ward & Prince, 1991) and stylistic stigmatization in formal context (Zribi-Hertz, 1994). We claim that these constraints are all pragmatic in nature and that their interaction weight on the use of clitic left dislocation in French. These claims are tested empirically via a corpus studies, a series of acceptability judgment tests and a matched guise test. Furthermore, we argue that the learning of pragmatic constraints in foreign language is dependent of their explicit teaching and repeated expositions to the construction in felicitous contexts. Following the dynamic interface hypothesis (Ellis, 2005), we suggest that explicit learning of the constraints of clitic left dislocation in the context of the classroom facilitates their implicit learning when the learners find themselves in a situation of communication with French native speakers. The role of exposition is explored empirically by replicating an acceptability judgment test and the matched guise test with non-native participants. Finally, all of our observations are tentatively implemented to didactic discourse with the help of notions and a terminology already used in pedagogical grammars (Germain & Séguin, 1998). Discursive constraints of clitic left dislocation are described using the distinction between old and new information (Capelle & Gidon, 1999; Watorek, 1998). Stylistics constraints are described using existential competencies and sociolinguistics registers (European Framework, 2001)
28
Akpossan, Johanne. "La consonne /R/ comme indice de la variation lectale : cas du français en contact avec le créole guadeloupéen." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015PA030010/document.
Full textAbstract:
Cette thèse a pour objectif de définir l’apport de la phonétique expérimentale dans l’identification d’une variété lectale, en prenant pour exemple les langues parlées en Guadeloupe. En Guadeloupe, deux langues cohabitent : le français et le créole. Mais, dans les faits, il y a une diversité de variétés de français d’une part, et de créole d’autre part. Chacune de ces variétés va de l’acrolecte au basilecte en passant par le mésolecte : il y a donc un continuum français et un continuum créole. La situation sociolinguistique de la Guadeloupe peut être ainsi représentée par un double continuum.Ces différentes variétés de français peuvent-elles se distinguer par des caractéristiques (1) acoustiques, (2) phonétiques, (3) phonologiques et (4) perceptives de la consonne /R/? La durée du contact avec le créole, a t-elle une influence sur la variété de français parlée par un locuteur ?Nos résultats montrent que plus la variété de français est basilectale, (1) plus la diffusion de l’énergie spectrale du /R/ est faible avec un taux de bruit réduit et une hauteur moyenne des fréquences basse ; (2) plus la variante fricatisée du /R/ est rare et plus la variante approximante est fréquente ; (3) plus le taux d’élision du /R/ en coda de syllabe augmente ainsi que le taux de réalisation de /R/ en tant que [w] en contexte labial; (4) plus la variété est perçue comme ayant un faible degré d’accent français. Généralement, plus la durée du contact entre le français et le créole est longue, plus cette variété est basilectale.Si les caractéristiques de la consonne /R/ permettent de discriminer la variété acrolectale de la variété basilectale (variétés extrêmes), il apparait plus difficile d’établir une liste d’indices (ou « lectomètres ») qui permettraient d’identifier les variétés se trouvant dans la zone intermédiaire : le mésolecte est doté d’une certaine imprévisibilitéThe goal of this thesis is to determine the contribution of experimental phonetics in the identification of a lectal variety, in taking for example languages spoken in Guadeloupe. In Guadeloupe, two languages coexist : French and Creole. But in fact, there is a diversity of varieties of French on the one hand, and of Creole on the other hand. Each of these varieties goes from acrolect to basilect through mesolect : so there are a French continuum and a Creole continuum. Thus, the sociolinguistic situation of Guadeloupe can be represented by a double continuum.These different varieties of French can they be distinguished by (1) acoustic, (2) phonetic, (3) phonological (4) and perceptual characteristics of /R/ consonant? Does the contact duration with Creole have an influence on the variety of French spoken by a speaker?Our results show that the more basilectal the variety of French is, (1) the lower spectral diffusion of /R/ energy is, with a reduced rate noise and a low frequency mean; (2) the more infrequent /R/ constrictive variants are and the more common /R/ approximant variants are ; (3) the greater rates of /R/ elision in coda of syllable and /R/ realization as [w] in labial context increase ;(4) and the more the variety is perceived as having a low degree of French accent. Usually, the longer duration of the contact between French and Creole is, the more basilectal the variety of French is.If characteristics of /R/ consonant can distinguish acrolect and basilect (extreme varieties), it’s not so easy to establish a list of indications (or « lectomètres ») in order to identify varieties in the intermediate zone: mesolect has a certain unpredictability
29
Aqeeli, Mohammed Ali M. "Microwave oscillator with phase noise reduction using nanoscale technology for wireless systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/microwave-oscillator-with-phase-noise-reduction-using-nanoscale-technology-for-wireless-systems(46287d2a-bc90-4cee-b893-ccf6a3b0747f).html.
Full textAbstract:
This thesis introduces, for the first time, a novel 4-bit, metal-oxide-metal (MOM) digital capacitor switching array (MOMDCSA) which has been implemented into a wideband CMOS voltage controlled oscillator (VCO) for 5 GHz WiMAX/WLAN applications. The proposed MOMDCSA is added both in series and parallel to nMOS varactors. For further gain linearity, a wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to four nMOS varactor pairs, each of which is biased at a different voltage. Thus, VCO tuning gain reduces and optimal phase noise variation is obtained across a wide range of frequencies. Based on this premise, a wideband VCO is achieved with low phase noise variation of less than 4.7 dBc/Hz. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.45 GHz to 6.23 GHz, with a phase noise of -133.80 dBc/Hz at a 1 MHz offset, a figure of merit (FoM) of -203.5 dBc/Hz. A novel microstrip low-phase noise oscillator is based on a left-handed (LH) metamaterial bandpass filter which is embedded in the feedback loop of the oscillator. The oscillator is designed at a complex quality factor Qsc peak frequency, to achieve excellent phase noise performance. At a centre frequency of 2.05 GHz, the reported oscillator demonstrates, experimentally, a phase noise of -126.7 dBc/Hz at a 100 kHz frequency offset and a FoM of -207.2 dBc/Hz at a 1 MHz frequency offset. The increasing demands have been placed on the electromagnetic compatibility performance of VCO devices is crucial. Therefore, this thesis extends the potential of highly flexible and conductive graphene laminate to the application of electromagnetic interference (EMI) shielding. Graphene nanoflake-based conductive ink is printed on paper, and then it is compressed to form graphene laminate with a conductivity of 0.43×105 S/m. Shielding effectiveness is experimentally measured at above 32 dB as being between 12GHz and 18GHz, even though the thickness of the graphene laminate is only 7.7µm. This result demonstrates that graphene has great potential for offering lightweight, low-cost, flexible and environmentally friendly shielding materials which can be extended to offering required shielding from electromagnetic interference (EMI), not only for VCO phase noise optimisation, but also for sensitive electronic devices.
30
Cunha, Antonio Rodrigues da. "Estudos teóricos de propriedades estruturais e eletrônicas da molécula emodina em solução." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-09042010-104047/.
Full textAbstract:
Estudamos as propriedades estruturais e eletrônicas da molécula emodina (EM), em diferentes condições, do ponto de vista experimental e teórico. Numa primeira parte, realizamos medidas do espectro eletrônico de absorção da EM, em meio solvente (água, clorofórmio e metanol). Nessa parte, obtivemos que o solvente provoca pouco efeito nos deslocamentos das bandas. Numa segunda parte, estudamos a EM, isoladamente e nos três solventes, através de cálculos quânticos com funcional de densidade (B3LYP), conjunto de função base de Pople (6-31G*) e modelo contínuo polariz ável (PCM). Como principais resultados obtivemos que a EM é rígida a menos da orientação relativa das 3 hidroxilas. A mudança orientacional nessas hidroxilas pode provocar formação de até 2 ligações de hidrogênio intramolecular (o que estabiliza sua geometria) e conseqüente uma diminuição no momento dipolo de 5.5 a 1.7D (o que desestabiliza sua interação com a água). Numa terceira parte, realizamos simulações com método Monte Carlo e Dinâmica Molecular em solução. Nessa parte, obtivemos que as ligações de hidrogênio intramoleculares são raramente quebradas devido as interações com o solvente e isso atribui a EM um caráter hidrofóbico. Adicionalmente, utilizando Teoria de Perturbação Termodinâmica nas simulações, calculamos a variação de energia livre de solvatação da EM em partição água/clorofórmio e água/- metanol e obtivemos -2.6 e -4.9 kcal/mol, respectivamente. Esse resultado está em boa concordância com o resultado experimental de -5.6 kcal/mol para partição de água/octanol. Por último, realizamos cálculos do espectro eletrônico de absorção da EM, isoladamente e nos três solventes, considerando as moléculas através do modelo, contínuo de solvente (SCRF) e explícito de solvente, com o método INDO/CIS. Nessa parte, obtivemos que o efeito do solvente é bem descrito teoricamente.We study the structural and electronic properties of the emodin (EM) in different solvents of experimental and theoretical the point of view. We started performing measurements of the UV-Vis absorption spectrum of the EM in solution (water, chloroform and methanol). Our main result is that the solvent causes little effect on shifts the bands. In the second part of this work, we performing quantum calculations of isolated EM and in the three solutions using density functional (B3LYP), a set of Pople basis function (6-31G*) and the polarizable continuum model (PCM). In this part, our result is that EM presents a rigid conformation unless the orientation of its 3 hydroxyls. The change in these hydroxyls orientation can form up to 2 intramolecular H-bonds (which stabilizes its geometry) and causes a decrease in the dipole moment from 5.5 to 1.7D (which destabilizes its interaction with water). In the third part of this work, we performing Monte Carlo and Molecular Dynamics simulations in solution. Our main result is that the intramolecular H-bonds are rarely broken, even in aqueous solution, and these give to EM a hydrophobic character. Additionally, using Thermodynamics Perturbation Theory in the simulations, we calculate variations of free energy of solvation of EM in partition of water/chloroform and water/methanol and obtained -2.6 and -4.9kcal/mol, respectively. This last result is in good agreement with the experimental result[3] of -5.6kcal/mol for partition of water/octanol. Finally, we performing calculations of UV-Vis absorption spectrum of isolated EM and in the three solutions. In this calculations, we considering the molecules through the continuum solvent (SCRF) and explicit solvent model with the method INDO/CIS. In this part, we obtaining that effect of solvent is well described theoretically.
31
Fantognon, Comlan Xavier. "Analyse émergentiste des pratiques enseignantes en FLES : cas de l’appropriation de l’IFADEM au Bénin. Entre contextualisation, réflexivité et médiation." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCA129/document.
Full textAbstract:
Située au carrefour de la didactique des langues et cultures et des sciences de l’éducation, la présente thèse porte sur l’appropriation, par les enseignants du cycle primaire au Bénin, de l’Initiative Francophone pour la Formation à Distance des Maîtres (IFADEM) en tant que dispositif de formation continue, en enseignement-apprentissage du FLES. L’objectif consiste à apporter des pistes pour améliorer l’appropriation du dispositif. A partir d’un modèle théorique d’appropriation, mis en place au regard d’une approche théorique transdisciplinaire et des spécificités du contexte d’étude, doublé d’une démarche de triangulation articulant enquêtes par questionnaires, par entretiens semi-directifs, d’auto-confrontation et par observations de pratiques effectives (situantes), nous nous sommes attachés à identifier les « indicateurs » d’appropriation ainsi que les « effets » du dispositif de formation sur les « pratiques pédagogiques effectives » des enseignants. Les théories holistiques de l’apprentissage des langues et spécifiquement l’éducation bilingue, le translanguaging et les théories sur l’enseignement-apprentissage de l’oral, ont constitué un socle pour l’analyse et la compréhension de la situation de recherche. La stabilité de nos analyses, offerte par le choix d’une méthodologie par triangulation, confirme que le parcours d’appropriation est déterminé par des relations d’interdépendance entre des facteurs situationnels (contextualisation), relationnels (relation avec les pairs) et individuels (self-system, réflexivité, recul épistémologique). Elle nous permet également d’aboutir aux conclusions suivantes : les enseignants bénéficiaires de la formation IFADEM font usage de la formation de façon instrumentale, et notamment des tâches qui leurs sont proposées pour améliorer l’enseignement oral du et en français afin de faire face au plurilinguisme. Ils sont exposés à plusieurs variations d’échelle, sources de contraintes et de tensions dans leurs activités pédagogiques, et ces dernières constituent un frein à l’appropriation du dispositif. L’analyse du processus d’appropriation au regard de l’émergentisme et des systèmes complexes d’activité permet d’aboutir au fait que les tensions générées par le déploiement du dispositif IFADEM font partie intégrante du processus de transformation de ce dernier. C’est l’absence de feed-back soutenu et institutionnalisé qui constitue une entrave à l’appropriation du dispositif. Afin de réagir positivement à ces écarts et de garantir l’appropriation du dispositif, le recours à la médiation ainsi qu’à une approche par tâches constituerait une voie intermédiaire. Elle permettrait notamment au dispositif de formation IFADEM, de s’inscrire dans une démarche co-évolutive, essentielle à l’équilibre des systèmes. C’est en tenant compte de l’ensemble de ces analyses et ajustements que cette recherche aboutit à l’élaboration d’un modèle d’appropriationThis PhD thesis, situated at the crossroads of two domains – language and culture learning and teaching and learning sciences – deals with the way Beninese primary school teachers appropriated the IFADEM programme - « Initiative Francophone pour la Formation à Distance des Maîtres » (Francophone Initiative for Distance Education of Teachers), as a lifelong education environment in the teaching and learning of « French as Foreign/Second Language Learning ». Our purpose is to suggest new avenues aimed at improving the appropriation of this education environment. Our approach is based on a theoretical model of appropriation informed by a transdisciplinary theoretical stance and by the specifics of the context under study, but also on a triangulation method mixing questionnaire surveys, semi-directive interviews, self-confrontation interviews and observations of actual practises (situating). We try to identify the « indicators » of appropriation as well as the « effects » of the education environment on the « actual pedagogical practises » of teachers. Holistic theories of language learning – and more specifically bilingual education, translanguaging and the theories on oral skills development have given a foundation to the analysis and the comprehension of the research situation. The stability of our analyses, made possible by the choice of a triangulation methodology, confirms that the appropriation paths are determined by interdependency relations between factors of situational (contextualisation), relational (relationships with peers) and individual (self-system, reflexivity, epistemological distancing) natures. It also allows us to reach the following conclusions : the teachers who benefitted from the IFADEM training use it instrumentally and more specifically use the tasks they were proposed to improve the teaching of oral skills in and of French, in order to tackle the question of plurilingualism. These teachers are faced with several scale variations which engender constraints and tensions in their pedagogical activities, thus hindering the appropriation of the education environment. The analysis of the appropriation process in the light of emergentism and of complex systems of activity leads to the conclusion that the tensions generated by the implementation of the IFADEM progamm are part and parcel of its process of transformation. The absence of institutionalised and sustained feedback is the real hindrance to the appropriation of the education environment. In order to reduce these discrepancies in a positive way and to guarantee appropriation, turning to mediation and a task-based approach would constitute a middle way. In particular, it would allow the IFADEM environment to come within the scope of a co-evolutive approach, which is essential to the balance of systems. Taking into account all these analyses and adjustments helps this research to reach the elaboration of a model of appropriation
32
Thivin, Viviane. "Expériences littéraires de la créativité et créativité en didactique du français enseigné comme langue étrangère. : un printemps du FLE." Thesis, Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCA037.
Full textAbstract:
Avancer que le texte littéraire a joué un rôle dans l’évolution des pratiques d’enseignement / apprentissage du FLE peut paraître une évidence. Pourtant, la place accordée aux textes littéraires diffère dans le temps. Or, c’est à un moment où les manuels de cours se détournaient le plus de ces textes que des didacticiens spécialistes du FLE se sont servi presque paradoxalement de la littérature pour élaborer de nouvelles activités qui devaient révolutionner la façon d’enseigner et d’apprendre la matière. Élaborées dans la période des années post soixante-huit, ces activités ont modifié à la fois le rôle de l’enseignant et la place de l’apprenant dans la classe. À l’instar de la littérature qu’il enseignait jusqu’alors, le premier perdait de son influence et se muait en animateur bienveillant. Quant au second, il devenait désormais actif et gagnait en autonomie. Libérées des méthodes du passé, les deux parties poussées à plus d’investissement personnel, devaient également trouver plus de plaisir dans leurs nouveaux rôles.Les littératures à l’origine de ce bouleversement sont dites « créatives ». Leurs modes de production reposent soit sur des techniques visant à libérer les auteurs des règles enclavant leur inventivité, soit sur des contraintes favorisant la production d’énoncés répondant à des modèles préétablis. Il va sans dire qu’appliquées dans les cours de FLE, les deux façons de procéder devaient conduire les apprenants à produire des textes dits créatifs à leur tour. La présente recherche porte sur les textes littéraires utilisés et les exercices qu’ils ont engendrésTo advance that the literary text has always played a part in the evolution of the practices of teaching/training of French as Foreign Language (FFL) is an obviousness. The place granted to it differs of course in time. However, it is at the moment when the handbooks were turning away from these texts that the didacticians, specialists in FFL, made use of the literature to work out new activities. The latter were to revolutionize the way of teaching and learning the matter. Worked out during the years of post-68, these activities modified the role of the teacher as well as the place of the learner in the class. Following the example of the literature which he taught hitherto, the first lost of its influence and turned into a benevolent instructor. As for the second, from then it became active and gained in autonomy. Released from the methods of the past, the two thorough parts with more personal investment were to also find more pleasure in their new roles.The literatures at the origin of this upheaval are known as «creative». Their modes of production rest either on techniques aiming at releasing the authors of the rules wedging their inventiveness or on constraints supporting the production of types based on prerequisites. It goes without saying that, applied to the FFL courses, the two ways of proceeding should lead learners in turn to produce texts known as «creative». The present research relates to the various literary techniques used and the exercises which they generated
33
YaoTsao and 曹瑤. "A study of free surface variation induced by Seabed movements." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2ezpp5.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系
107
In this study, the theoretical analysis method is used to investigate the fluctuation of the water surface caused by the bed movements. Exploring a finite-length water tank, the boundary of the bed is stopped after the constant velocity upward movement from the standstill to cause the fluctuation of the water surface. Discussing the relationship between the maximum water level pattern caused by bed movement and its variable parameters to understand the influence of various parameters on the water level. Because it is similar to the piston-type wavemaking method, it is compared with that to explore the difference between the two. In the method, the problem is linearized by the small amplitude wave theory, and the space is transformed by the finite Fourier cosine transform of Lee et al (1989). And do not convert the time, thereby improving the solution method, verifying that the water level function converges, and then analyzing the analysis results. The results show that the displacement stroke is proportional to the maximum water level. When the time of displacement increases, the time of maximum water level increases, the maximum water level decreases, the water wave width increases, and the maximum water level pattern becomes wider and flatter, and it is found that the boundary displacement of the bottom produces a maximum water level with a wider water wave width and a lower wave height; and the boundary displacement of the lateral produces a maximum water level with a narrower water wave width and a higher wave height.
34
Lin, Ren-Jeng, and 林仁正. "Multiple Cracks Identification of Free-Free Beam with Uniform Material Property Variation and Noised Frequency Measurement." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/96279169909450831632.
Full textAbstract:
博士國立交通大學
土木工程系所
97
It is common to apply damage-sensitive features from vibration response for structural damage assessment. Fewer damage identification algorithms have been taken into account the material variation. The material variation could be caused by many reasons in engineering practice, also there may exists certain level noise in measurement, these variations may affect the features used for structure monitoring and lead to an inaccurate damage assessment. In this research the authors proposed a model to assess statistical structural damage of free-free beam structure. The modal curvature-base feature was used to identify crack location. The statistical database for damage severity assessment was build by applying the Monte Carlo simulation with Latin hypercube sampling. By mapping vibration-sensitive features with noised modal frequency to statistical damage database, the damage probability among various crack depths were then estimated; its statistical significance of damage level were examined by the t-test. Data from simulated beams and experimental modal analysis were used to demonstrate the assessment procedures. From the results, the authors concluded that the proposed algorithm was robust and able to identify the damage of free-free beam under uniform mass density and stiffness variations incorporated with noise in measured frequency.
35
Hoosen, Nikhat. "Patterns of genetic variation in Mops leucostigma (Molossidae) from Madagascar and the Comoros." Thesis, 2008. http://hdl.handle.net/10413/8296.
Full textAbstract:
The synanthropic molossid bat, Mops leucostigma (Allen 1918), is widely distributed across
Madagascar and has recently been described from the Comoros. M. leucostigma individuals
from eastern Malagasy populations are markedly larger than those from the west, and Mops
leucostigma populations from Madagascar are morphologically distinct from populations of its
putative sister species, Mops condylurus from mainland Africa (Ratrimomanarivo et al. in press,
Genetic diversity was assessed by sequencing the mitochondrial cytochrome b (n = 56) and
displacement loop (D-loop) (n = 64) regions of Mops leucostigma individuals from a broad
range of locations across Madagascar, and Mohéli and Anjouan in the Comoros. Specimens of
Mops condylurus (n =3), Mops midas (n =3) and Otomops martiensseni (n = 1) were included in
the study for comparative purposes as outgroups. Phenetic and cladistic analysis of cytochrome
b and D-loop sequences strongly supported the reciprocally-monophyletic status of Mops
condylurus and M. leucostigma. Comorian (Mohéli and Anjouan) and Malagasy M. leucostigma
samples formed a monophyletic Mops leucostigma group, within which Comorian samples
formed a poorly-supported subclade in the cytochrome b analysis only. Cytochrome b genetic
distances of 13.8 % separated M. midas from M. condylurus and M. leucostigma, which formed
reciprocally-monophyletic sister groups separated by genetic distances of 2.5 % for cytochrome
b and 13 % for the D-loop. 49 M. leucostigma cytochrome b sequences yielded seven
haplotypes, two of which were exclusive to the Comoros. D-loop haplotype analysis did not
support the distinctiveness of the Comorian samples. Genetic distances within M. leucostigma
samples were low (0.22 % for cytochrome b and 1.91 % for the D-loop). Comorian samples
were found to be genetically attributable to M. leucostigma. Clear phylogenetic separation
between M. condylurus and M. leucostigma was found in all analyses, consistent with their
status as phylogenetic species within the genus Mops. There was no clear correlation between
haplotype distribution and aspect (east/west-facing slopes), elevation or gender. Low mtDNA
variation (cytochrome b and D-loop) and lack of phylogeographic concordance indicates that
the observed morphometric variation between eastern and western Mops leucostigma
populations may possibly be explained in terms of adaptation to local environmental conditions.Thesis (M.Sc.)-Univeristy of KwaZulu-Natal, 2008.
36
Tsai, Chien-wen, and 蔡建文. "Variation of pressure distribution downstream of free overfall due to different dissipation arrangement." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/36889707744916194963.
Full textAbstract:
碩士國立中興大學
土木工程研究所
81
Based on the previous experimental studies for free over- fall, the main influencing factors of the local scour down- stream of the drop structure are the position of nappe and the force density on channel bed. In this research, the pressure transducer and strain amplifier, which do not disturb the flow field, were set up. The pressure distribution along the streamwise direction downstream of the weir were measured through an A-D converter, and compared with the data collected by Moore and Rand. The energy decay under different void ratios for experiments with various dissipation block arrange- ments were investigated. Finally, the influences of the po- sition of end sill on the flow field and energy dissipation were alsostudied experimentally.
37
Räß, Michael [Verfasser]. "Annual timing and life-history variation in free-living stonechats / vorgelegt von Michael Räß." 2005. http://d-nb.info/982838158/34.
Full text
38
Lo, Ming-Huang, and 羅明煌. "The derivation of expression for the 4-th order free-energy variation of biomembrane' deformation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/43578972721132406936.
Full textAbstract:
碩士國立中正大學
物理系
90
The shape energy of a biological membrane was formulated previously in terms of the Helfrich Hamiltonian. Due to the softness of the biomembrane its surface usually undergoes large deformations even at room temperature. Here we extend the work by Ou-Yang and Helfrich, to expand the bending energy up to 4-th order in the deformation function with the help of the differential geometry tools. After obtaining 4-th order correction for the bending energy, we investigate its role in the bending deformation by illustrating two special cases --- the spherical and cylindrical surfaces. In the case of a sphere, we restricted ourselves to its two possible shapes, a prolate and an oblate ones. The analysis indicates that, upon taking account of 4-th order corrections, the critical value determining the oblate-to-prolate transition will behave in a more complicated way than the case being considered only up to 3-rd order corrections. We also compare the present results with the previous ones. In the case of a circular cylinder, two special surface deformations were considered and stable conditions for the surface under such deformations are found. The formation of possible surface shapes slightly deviated from a cylinder are also predicted.
39
Boucher, Krystel. "Compréhension orale de variantes linguistiques des registres de langue du français québécois chez des allophones adultes en francisation." Mémoire, 2012. http://www.archipel.uqam.ca/4827/1/M12394.pdf.
Full textAbstract:
Depuis 1968, le Ministère de l'Immigration et des Communautés culturelles (MICC) offre des cours de francisation pour les nouveaux immigrants allophones adultes. Ce programme a pour objectif « d'acquérir à la fois la maitrise de la langue et la connaissance des codes culturels et de communiquer efficacement à travers différentes situations de la vie quotidienne » (PGIL, 1992, p. 1). Cependant, les responsables œuvrant dans le domaine de la francisation et les étudiants immigrants allophones affirment, dans le cadre d'études qualitatives, que ces derniers, au terme du programme de francisation de 990 heures, ne sont pas aptes à communiquer de façon satisfaisante à travers plusieurs situations de communication de la vie courante. Ce mémoire s'est donc penché sur la compréhension orale des variantes linguistiques du parler du français québécois. Quarante-deux apprenants adultes immigrants âgés en moyenne de 33 ans et provenant de groupes de classe de l'école MICC-UQAM ont participé à l'étude. Ils devaient écouter un dialogue de registre neutre, basé sur les grammaires de l'écrit, un dialogue de registre familier, basé sur un le français québécois parlé spontanément, et répondre ensuite à un questionnaire à choix multiples. Le nombre de bonnes réponses ont été compilé suivi d'un T-test comparant les moyennes de la compréhension orale des registres neutre versus familier. Il a été observé que le taux de réussite de la compréhension orale du registre familier est significativement inférieur à celui du registre neutre. De plus, puisque le débit a été contrôlé dans ces évaluations, il y a de fortes chances que cette compréhension orale diminue dans une situation de communication naturelle. Dans un autre ordre d'idées, l'étude montre que lorsqu' il y a peu de variantes linguistiques dans un discours oral, la compréhension orale n'est pas affectée chez les sujets. À l'inverse, lorsque plusieurs variantes linguistiques sont présentes dans un discours oral, la compréhension est affectée. Il semble aussi que le type (la nature) des variantes linguistiques joue un rôle prédominant dans la compréhension orale. Les résultats quantitatifs de cette recherche viennent appuyer les résultats qualitatifs d'études précédentes. Il semble qu'au terme de la formation en francisation, les étudiants n'ont atteint que partiellement l'objectif « d'acquérir à la fois la maitrise de la langue et la connaissance des codes culturels et de communiquer efficacement à travers différentes situations de la vie quotidienne » (PGIL, 1992, p. 1).
______________________________________________________________________________
MOTS-CLÉS DE L’AUTEUR : compréhension orale, registre de langue, variation linguistique, français langue seconde
40
Tsai, Chin-chieh, and 蔡進潔. "The Effects of Geometric Parameters Variation on Lead-Free Flip-Chip Package under Temperature Cycling Test." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/8ny58s.
Full textAbstract:
碩士國立中山大學
機械與機電工程學系研究所
95
Thermal fatigue failure, due to the fracture of solder bumps which was cased by the coefficient of thermal expansion mismatch deformation, is frequently encountered in flip-chip package. Therefore, this thesis attempts to study the effects of geometric parameters variation on lead-free flip-chip package under temperature cycling test. First, we used the finite element method to simulate the thermal loading response of lead-free flip-chip. The accumulated equivalent creep strain and accumulated creep strain energy density of the lead-free solder bumps were calculated, and were used to predict the thermal fatigue life of lead-free flip-chip package. The Taguchi method is applied to obtain the optimal design parameters in order to enhance reliability of the lead-free flip-chip under temperature cycling loading. The analysis of variance (ANOVA) is also used for estimating the influence of the factors quantitatively. The obtained results can be adopted as references for the lead-free flip-chip package design.
41
"Biological variation of total (peroxyl) radical-trapping antioxidant parameter (TRAP) in a healthy Chinese population." Chinese University of Hong Kong, 1994. http://library.cuhk.edu.hk/record=b5887182.
Full textAbstract:
by Hui Yee Han, Ellen.Thesis (M.Sc.)--Chinese University of Hong Kong, 1994.
Includes bibliographical references (leaves 68-71).
acknowledgements --- p.i
abstract --- p.ii
table of contents --- p.iii-vi
list of figures --- p.vii
LIST OF TABLES --- p.viii
chapter
Chapter chapter i : --- introduction --- p.1
Chapter chapter ii : --- background knowledge --- p.2 -33
Chapter 2.1 --- Definition of Free Radical --- p.2
Chapter 2.2 --- Oxygen Derived Radicals and Their Generation In Vivo --- p.2 -9
Chapter 2.2.1 --- Production of Singlet Oxygen --- p.4
Chapter 2.2.2 --- Production of Superoxide Radical (O2-) and Hydrogen Peroxide (H2O2) --- p.4 -8
Chapter I. --- Endogenous Production --- p.4-7
Chapter II. --- Exogenous Production --- p.7-8
Chapter 2.2.3 --- Generation of Hydroxy Radical (OH) through H2O2 and O2- --- p.8 -9
Chapter 2.3 --- Free Radical Damage and Lipid Peroxidation --- p.9 -13
Chapter 2.4 --- Lipid Peroxidation and Atherosclerosis --- p.13 -14
Chapter 2.5 --- Antioxidant --- p.15-21
Chapter 2.5.1 --- Primary Preventive Antioxidants --- p.15-17
Chapter 2.5.2 --- Secondary Radical Scavenging Antioxidants --- p.18-21
Chapter I. --- Lipid Soluble Radical-Scavenging Antioxidants --- p.18-19
Chapter II. --- Water Soluble Radical-Scavenging Antioxidants --- p.20 -21
Chapter 2.6 --- Measurement of Oxygen-Derived Radical in Vivo --- p.21 -26
Chapter 2.7 --- Principle of the TRAP assay --- p.27-33
Chapter 2.7.1 --- Oxygen Consumption Method --- p.29 -30
Chapter 2.7.2 --- Chemiluminescence Method --- p.31-33
Chapter chapter III： --- materials and methods --- p.34 -43
Chapter 3.1 --- Instrumentation and Materials --- p.34
Chapter 3.2 --- Method --- p.34-43
Chapter 3.2.1 --- Establishment of Chemiluminescence Method for Determination of TRAP --- p.34 -36
Chapter I. --- Preparation of Luminometer --- p.35
Chapter II. --- Preparation of Sample before Analysis --- p.3 5
Chapter III. --- Manual Operation of the Chemiluminescence Method --- p.35-36
Chapter IV. --- Calculation of TRAP --- p.36
Chapter 3.2.2 --- Evaluation of the Chemiluminescence Method --- p.37 -42
Chapter I. --- Linearity --- p.37
Chapter II. --- Recovery --- p.37-38
Chapter III. --- Precision --- p.39
Chapter IV. --- Interference Experiment --- p.39 -41
Chapter V. --- Effect of Storage on TRAP --- p.42
Chapter 3.2.3 --- "Determination of Analytical, Intraindividual and Interindividual Biological Variation of TRAP in A Group of Healthy Chinese" --- p.42-43
Chapter CHAPTER IV: --- ANALYTICAL RESULTS --- p.44-56
Chapter 4.1 --- Method Evaluation --- p.44-51
Chapter 4.1.1 --- Linearity --- p.44
Chapter 4.1.2 --- Recovery --- p.45
Chapter 4.1.3 --- Within-Day and Between-Day Precision --- p.46-47
Chapter 4.1.4 --- Interference --- p.47-48
Chapter 4.1.5 --- Effect of Storage on TRAP --- p.48-51
Chapter 4.2 --- "Analytical, Intraindividual and Interindividual Variation of TRAP in A Group of Healthy Chinese Population" --- p.52 -56
Chapter 4.2.1 --- Difference in TRAP value obtained from the 22 subjects over time --- p.52 -54
Chapter 4.2.2 --- The Effect of Genders on Trap --- p.55
Chapter 4.2.3 --- "Determination of Analytical, Intraindividual and Interindividual Variation of TRAP in A Group of Healthy Chinese" --- p.55-56
Chapter CHAPTER V: --- DISCUSSION --- p.57-67
Chapter 5.1 --- Validation of the Method Performance --- p.57
Chapter 5.2 --- Effect of Storage on TRAP --- p.57
Chapter 5.3 --- Interference of Hemolysis and Lipemia on TRAP assay --- p.58-60
Chapter 5.3.1 --- Effect of Hemolysis on TRAP --- p.58-59
Chapter 5.3.2 --- Effect of Lipemia on TRAP --- p.59-60
Chapter 5.4 --- Possible Sources of Variation in TRAP Over Time --- p.60 -63
Chapter 5.5 --- Usefulness of the Variation Data of TRAP obtained from a Group of Healthy Chinese --- p.64 -67
reference --- p.68 -71
42
Nassenstein, Nico. "On the variability of Kiswahili in Bujumbura (Burundi)." 2019. https://ul.qucosa.de/id/qucosa%3A70969.
Full textAbstract:
The variety of Kiswahili spoken in Bujumbura (Burundi) is central to the present sociolinguistic and structural analysis. Swahili in Burundi looks back upon a long history: first having been introduced by the German colonial administration, it has turned into a trade language along both the naval and non-naval trade routes between Uvira (DR Congo), Kigoma (Tanzania) and Bujumbura. Initially stigmatized as a language of ruthless urban rioters in the post-conflict era, it has increasingly gained popularity in Bujumbura, and is nowadays considered as one of the languages of Burundi, alongside Kirundi, French and English. Especially in the lively neighborhoods of the big- gest city, where there is a pulsating nightlife, Kiswahili can be heard in many interactions, and of- ten reveals influence from Kirundi, French, English and sometimes even Lingala. Structurally, the Swahili of Bujumbura combines elements from East Coast Swahili (ECS) as spoken in Tanzania and from Congo Swahili regiolects such as Kivu Swahili, and reveals a high degree of variability, depending upon interlocutors, contexts of interaction and communicative purpose. In this contribution, apart from summarizing the sociohistorical background and suggesting sociolinguistic approaches to grasping the high degree of variability in Kiswahili in Burundi, I discuss the most salient phonological and morphosyntactic patterns of variation and explain their situational distribution.
43
Hsien, Li Chun, and 李俊賢. "The study of thermal fatigue on lead free solder ball by shearing behavior and intermetallic compound variation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/37390800757919277297.
Full textAbstract:
碩士國立高雄應用科技大學
電機工程系
97
Nowadays, utilizing lead-free materials in electrical assembly has become an unavoidable tendency. The main goal of this thesis is to discuss the relation between the thickness made by shearing behavior and IMC variation and the time period of maintaining high temperature. The survey subjects are 0.6mm lead-free solder balls made of Tin(96.5%)、Silver(3%)、Copper(0.5%). The condition of high-temperature storage is 150℃ and the time period of storage is from 0 to 4000 hours. Besides, the observation frequency is once in every 250 hours. The result of this study has shown that the (Cu, Ni) 6Sn5 phase is formed at the interface. After long heating treatment, (Cu, Ni) 6Sn5 phase gradually turns into (Ni, Cu) 3Sn phase, and the thickness of (IMC) increases when the time period of high-temperature storage gets longer. And as for the shearing intensity, the experiment has shown that ball-shearing value starts to decrease relatively while the time of heating treatment gets longer. After comparing the differences between the shearing intensity in different heating treatments, the main reason for the decrease of shearing intensity is found. It is because the destructive model changes form external extended destruction to internal stress destruction. Besides, under the observation in the SEM, the internal stress destruction result from the break of (Cu, Ni) 6Sn5 and (Ni, Cu) 3Sn.
44
HSU, CHIH-CHAN, and 許志群. "Removal of Salt-and-Pepper Noise Using Gain Factors Adapted by Noise-Free Pixel Number and Pixel Variation." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/k5bz92.
Full textAbstract:
碩士亞洲大學
資訊傳播學系
105
A digital image would be corrupted by impulse noise at the time of capturing or transmission, causing the quality of the image to be deteriorated. Noise interference is disadvantageous for further process on the noise-corrupted image. How to effectively remove this impulse noise for a noise-corrupted image is an important research task. In this thesis, we propose a gain factor adapted by noise-free pixel number and pixel variation for the removal of salt-and-pepper noise, enabling the quality of the image to be improved. Initially, a sliding window with the size of 3x3 is employed to analyze the pixels with an extreme value of gray level (255 or 0 for an 8-bit gray-level image). All pixels with non-extreme value of gray level are sorted in an ascending order and are grouped according to the gray-level variation of pixels. If the gray-level variation of pixels between adjacent two sorted pixels varies seriously, a new group is created. Hence, the distribution ratio and median value of each group are computed to determine the values of the gain factors. They are multiplied with the median value of each group to obtain a weighted value which is employed to replace the center pixel with extreme value of gray level, enabling noise-corrupted pixels to be reconstructed. Experimental results show that the proposed approach can effectively remove salt-and-pepper noise from a corrupted image for various noise corruption densities (from 10% to 90%); meanwhile, the denoised image is not blurred.
45
Wu, Yi-Ju, and 吳怡儒. "Infrared Thermography Monitoring System for Microvascular Free Flap After Surgery: Flap Temperature Variation Detection Based on Independent Components Analysis." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ruk6sb.
Full textAbstract:
碩士國立臺灣大學
醫學工程學研究所
106
One of the most common cancer with the highest mortality rate is Oral cancer. The most frequently adopted approach of curative treatment of oral cancer is by resecting cancer legions and reconstructing the affected regions by unaffected tissues of the patient. Free flap surgery is a reliable reconstruction method operated by many medical professionals. However, circulatory compromises were sometimes observed within five to seven days after surgeries, even if the operations were performed by experienced microvascular surgeons. Furthermore, research shows that that the success rate of surgeries diminishes due to late detection of circulatory compromises. Therefore, monitoring and early detection of circulatory compromises signs are crucial to the free flap surgery. At present, clinical free flap care and monitoring are performed mainly through scheduled inspections by nursing staff. The caring process is labor-intensive and the success rate of detection varies owing to subjective judgement and experiences of carers. Other available methods of monitoring includes the continuity usage of monitor systems, which are invasive and incur higher cost. It is noticeable that an alternative method of monitoring is imminent. Therefore, previous scholars suggested infrared imaging as an alternative method to current monitoring for its inexpensive, non-invasive, non-contacting, non-radioactive, real-time, and repeatable features. Through the Factor Analysis algorithm, it could effectively remove the common factors of human physiology and observe the changes of real temperature. However, the method does not apply in more complex situations. If the estimation of common factors is not a linear combination of all factors but one factor occurs after another, the Factor analysis algorithms is unable to segregate the factors. Because if the estimated of the common factor is not a linear combination of all factors, but a certain factor occurs first and then a factor occurs later, then Factors Analysis algorithms can''t separate them. Therefore, based on theoretical basis of prior researches, this study aimed to analyze the unique features of the observed signals by using the Independent Component Analysis algorithms for its flexibility. Plus, the factors could not be easily explained by the Factor Analysis algorithm. Through the advantages and capabilities of the Independent Component Analysis algorithm, the study hope to propouse a temperature variation detection algorithm that is more suitable for the Infrared thermography monitoring system for microvascular free flap after surgery. Out of the four animal experiments and twenty-three cases monitored in the study, only one patient developed venous thrombosis. Through the Factors Analysis algorithm, we found that the temperature of the free flap had significantly decreased. According to the results of the Independent Component Analysis algorithm, we found that there was two independent factors that may affect the temperature of the free flap region. One of the independent factors could detect the drop of the temperature earlier than the result of the factor analysis, and the other is the same as the result of the Factor Analysis. Both of the results showed the potential of early detection in temperature changes comparing to nursing records. However, due to the limitation of sampling, the study was unable to provide further verifications and discussions. It is hoped that more data will be available in the future to support the aim analytical methods. The goal of this study it to setup a foundation in the development of an auxiliary monitoring tool to monitor free flap pedicel thrombosis after a lesion removal surgery.
46
Lan, Kung-An, and 藍功安. "Statistical Analysis and Effect of Solidification Structural Variation on Electrification-Fusion Phenomenon of Sn-Zn Lead-Free Solder Alloys." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/32709424149325006547.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系碩博士班
94
The fusion phenomenon for Sn-Zn binary solder alloys had been mainly discussed in this study and examined the variation of fusion current by varying the solidification rate, post treatment, and zinc content (x=7, 9, 11, 14wt%) of Sn-Zn alloys. This study focused on (a) the relation between melting latent heat of eutectic phase and fusion current examined by DSC analysis, and (b) experimental data of DC and AC condition plotted as Histogram and Boxplot pointed to data distribution, and examined the data fluctuation of fusion current data sets to acquire the variation of m value and reliability by Weibull analysis. The results of fusion current showed that the Zn-rich phases coarsened with decreasing the solidification rate. On the other hand, the melting latent heat of Sn-Zn eutectic phase was closely related to the value of fusion current. After post-treatment, a little influence of average fusion current value can be recognized. The results of specimen with different zinc content showed that the melting latent heat of Sn-Zn eutectic phase tended to decrease due to increasing the zinc content, the evidence was consistent with the increases of fusion current. Besides, there were 20 experimental data for each experimental parameter, each experimental data set by Weibull analysis showed that the data set of solidification rate indicated faster cooling specimens for DC cannot apply to Weibull analysis, medium and slower cooling specimens indicated Weibull modulus (m value) enen lower than 3.2; faster and slower cooling specimens for AC cannot apply to Weibull analysis. 1200C-post-treatment for DC and AC cannot apply to Weibull analysis, and 1800C-post-treatment specimens for DC indicated m value lower than 1.0; the data set of zinc content showed Sn-7Zn for DC and Sn-7Zn, Sn-14Zn for AC cannot apply to Weibull analysis, and the data set with higher zinc content, their m values significantly tended to decrease. A notable experimental result was that the experimental results of fusion current for AC and DC on Sn-Zn alloys commonly showed a Weibull modulus lower than 3.2 and even close to 1.0 that actually can be defined as a kind of random failure pattern. However, the above-mentioned experimental results depicted a reliability suspicion of the Sn-Zn alloys.
47
Chen, Ying, and 陳瑩. "A study on the free surface profiles in an open channel with cross-sectional variation by numerical and experimental methods." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49972125866116660134.
Full textAbstract:
碩士中原大學
生物環境工程研究所
101
In this study, we examined the 3D free surface profiles with downstream cross section expanded or reduced the least-squares finite element method (LSFEM) has been used to solve the momentum and mass conservation equations. The experimental results were compared with the simulation results and shown in good agreement with each other. The flow phenomena in the open channel with downstream cross-section variation were discussed in detail. By changing the inflow condition, the analysis between the simulation and experimental results stated that channel cross-sectional reduced will produce dramatically changes in water level, especially the water level in the upstream section where water accumulates in the corner. With the larger inlet velocity, the water level increasing phenomenon will be more obvious. The level of free surface at the side walls is larger than at the central of channel when the cross-section is changed. Regardless of the cross-section is gradually expanded or shrunk, with the larger inlet velocity, the lower free surface level.
48
Lu, Cheng-Che, and 呂政哲. "An Infrared Images Monitoring System for free flap Pedicle Thrombosis after surgery: Automatic Image Registration and Flap Temperature variation Detection." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/x8hzjb.
Full textAbstract:
碩士國立臺灣大學
醫學工程學研究所
106
Oral cancer is the fastest growing cancer in mortality rate in Taiwan. The most prevalent curative treatment of oral cancer exploits a multi-step approach starting with the resection of lesions. After the removal of cancer lesions, surgeons would employ unaffected tissues of the patients to reconstruct the affected regions. Free flap surgery is a reliable reconstruction method operated by many medical professionals. However, circulatory compromises were sometimes observed within five to seven days of surgeries, even when the operations were performed by experienced microvascular surgeons. Furthermore, it is documented that the success rate of re-surgeries diminishes as the detection of circulatory compromises delays. Therefore, it is crucial to monitor and detect signs of circulatory compromises quickly after the free flap surgery. At present, clinical free flap care and monitoring are performed mainly through scheduled inspections by nursing staff. This process is very labor-intensive and the success rate of detection varies greatly based on the opinions and experiences of the caregivers. Other currently available methods of monitoring, including the use of non-continuous monitoring systems, are invasive and incur higher costs. It is evident that an alternative method of monitoring is imminent. Previous scholars proposed infrared imaging as an inexpensive, non-invasive, non-contact, non-radioactive, rapid, and repeatable alternative to current monitoring methods. It was proposed that the image registration can be accomplished by manually selecting features points and utilize both factor analysis and eigenvalue analysis to observe temperature variation. However, such process was hand-operated and relies heavily on technician experience and time-consuming. Detection of temperature changes in free flap was prone to errors in the factor analysis algorithm. This study aimed to resolve the disadvantages of the manual image registration process by introducing an automatic longitudinal infrared image registration algorithm and a flap temperature variation detection algorithm. In this study, automatic longitudinal infrared image registration algorithm, utilizing the homography matrix coordinate transformation algorithm, was used to convert the free flap edge feature points detected under the visible light to infrared thermal images. After obtaining the infrared thermal image feature points, this study utilized non-rigid Coherence Point Drift (CPD) to calculate the corresponding relationship of the feature points. Using this relationship, the image registration was completed by affine transformation, so that the free flap regions at different time series were mapped together. After the registration, factor analysis was employed to analyze the temperature variation of free flaps to observe thrombosis. Out of the ten clinical cases monitored by this study, one patient developed venous thrombosis. Analysis using the methods proposed by this study indicated a significant temperature decrease in the subject''s free flap. In comparison to nursing records, it was discovered that the methods proposed by this study had the potential to detect temperature changes earlier. However, due to the sample size limitation, this study was unable to provide further verification and discussion. It is hoped that more data will be available in the future to support the proposed analytical methods. The goal of this study it to setup a foundation in the development of an auxiliary monitoring tool to monitor free flap pedicle thrombosis after a lesion removal surgery.
49
Liang, Wen Bin, and 梁文彬. "Seasonal variation in chemical composition, free amino acids, heavy metal and sanitary quality, and the effect of copper on the level of free amino acids in the small abalone haliotis diversicolor." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/12005892627306606580.
Full text
50
Yu, Chi-Yang, and 游濟陽. "Interfacial Reaction, Microstructure Variation, and Impact Reliability of Sn-based Pb-free Solder Joints with Ni, Cu, and Novel Cu-Zn Under Bump Metallurgy." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/15761939746256173998.
Full textAbstract:
博士國立清華大學
材料科學工程學系
101
In the flip-chip (FC) solder joint, solder alloys usually connect with Ni and Cu based under bump metallurgies (UBMs) at chip-side and substrate-side, respectively. The material selection for solder alloys and UBM material is a critical issue to affect the microstructure, phase formation, and the reliability of the solder joints. In this study, the interfacial reaction, microstructure variation, and impact reliability of Sn-based Pb-free solder joints with Ni, Cu, and novel Cu-Zn UBMs are discussed and categorized into six topics. (1) Microstructural variation and interfacial reaction in Ni/Sn-Ag-Cu/Ni assemblies with and without Ni doping Ni and Cu elements cross-interacted between the Cu and Ni UBMs during thermal aging and affected the interfacial reactions at both Cu and Ni sides. Dual-phased (Cu,Ni)6Sn5 intermetallic compounds (IMCs), which has high and low Ni concentration, formed at the solder/Ni interface. In contrast, thicker low-Ni (Cu,Ni)6Sn5 and thin (Cu,Ni)3Sn layers formed at the Cu side. The Ni doping into solder varied the microstructure of solder alloys and the formation of interfacial IMCs. The re-distribution of Ni and Cu was correlated to the formation mechanism of interfacial (Cu,Ni)6Sn5. (2) Effect of dual-phased (Cu,Ni)6Sn5 IMCs on the impact reliability of Sn-Ag-Cu/Ni solder joints By employing the high-speed shear impact test, the impact fracture morphology reveals that the interface of high-Ni (H)/low-Ni (L) (Cu,Ni)6Sn5 facilitates the crack nucleation within the IMC. It is believed that the crack propagation depends on the fracture toughness of interfacial IMCs. The indentation data shows that bulk H-(Cu,Ni)6Sn5 exhibits distinctly lower fracture toughness than bulk L-(Cu,Ni)6Sn5. In correlating the impact fracture behavior and mechanical properties of two kinds of (Cu,Ni)6Sn5, cracks tend to propagate through H-(Cu,Ni)6Sn5 due to the relatively low fracture toughness of H-(Cu,Ni)6Sn5. (3) Development of a novel Cu-Zn UBM for Pb-free solder joints To suppress the thicker IMCs and voids at the solder/Cu interface, the Cu-Zn alloy was designed for a novel UBM material. The interfacial reactions of Sn/Cu-xZn (x = 0, 15 and 30 at.%) solder joints were investigated. Interestingly, the growth of Cu-Sn IMCs was significantly reduced and no void was found in the Sn/Cu-Zn solder joints after thermal aging. Transmission electron microscopy (TEM) images and the field emission electron probe microanalyzer (FE-EPMA) analysis show that there are two types of Zn-rich phases, i.e. CuZn and Cu-Zn-Sn phases, to form in Sn/Cu-Zn joints. The formation mechanisms of IMCs were probed and proposed with regard to the thermodynamics and kinetics. (4) Liquid-state reaction of Sn-Ag-Cu solders and the novel Cu-Zn UBM During the reflow process, Cu and Zn atoms would dissolve from the Cu-Zn UBM into the molten solders, leading to the variation of the composition in the solders. Then, the composition variation further altered the microstructure of the solders. In comparison with the Sn-Ag-Cu/Cu, it was found that the coarser eutectic region and smaller Cu6Sn5 IMCs inside the solder matrix of Sn-Ag-Cu/Cu-Zn. In addition, the interfacial reaction was also affected by Zn dissolution. In this study, it was demonstrated that the microstructural variation and the phase evolution in the solder joints were controlled by the reflow time and the Zn concentration in the Cu-Zn UBM. (5) Characterization of the Cu6(Sn,Zn)5 intermetallic compound Cu6Sn5 is a dominant IMC at the Sn-based solder/Cu joint interface. The crystal structure of Cu6Sn5 varies with temperature. After reflow at 250 oC, the interfacial Cu6Sn5 revealed hexagonal structure (η-Cu6Sn5). During aging at 150 oC, hexagonal η-Cu6Sn5 would transform into monoclinic η’-Cu6Sn5. According to literature, the phase transformation between η’ and η would induce crack easily propagating through the Cu6Sn5 at the solder joint interface. In the novel solder/Cu-Zn joints, and Zn would dissolve into Cu6Sn5 to form the Cu6(Sn,Zn)5 IMC at the interface. X-ray diffraction and differential scanning calorimetry analyses show that doping small amounts of Zn into Cu6(Sn,Zn)5 can stabilize the hexagonal structure during the thermal aging process. Thermodynamic calculation also demonstrates that Zn can stabilize the hexagonal Cu6(Sn,Zn)5. (6) Application of Cu-Zn UBM on the Ni/Sn-Ag-Cu/Cu-Zn assemblies The feasibility of novel Cu-Zn UBM applied for the Ni/solder/Cu-Zn assemblies was also evaluated. In comparison with the Ni/Sn-Ag-Cu/Cu solder joint, Ni/Sn-Ag-Cu/Cu-Zn solder joints revealed thinner Cu6Sn5-based IMCs at both Ni/Sn-Ag-Cu and Sn-Ag-Cu/Cu-Zn interfaces after aging. (Cu,Ni)6(Sn,Zn)5/(Cu,Ni)6Sn5 dual-phase formed at the Ni side while (Cu,Ni)6(Sn,Zn)5 single-phase at the Cu-Zn side. The interfacial IMCs grew very slowly, and no void formed in these Zn-contained solder joints during thermal aging. Additionally, the dissolved Zn in the solder alloy reduced the elemental cross-interaction between the Ni and Cu-Zn substrates. The noticeable thermal stability of Ni/Sn-Ag-Cu/Cu-Zn solder joints is attributed to the Zn re-distribution retarding the reaction of Ni, Cu and Sn. Phase formation and IMCs suppression mechanisms in Ni/Sn-Ag-Cu/Cu-Zn solder joints were probed and discussed. In summary, novel Cu-Zn UBM shows lots of advantages for soldering, including: (I) reduction of Cu-Sn IMCs, (II) suppression of voids at the interface, (III) formation of the a hexagonal Cu6(Sn,Zn)5, and (IV) retardation of the elemental cross-interaction in the Ni/solder/Cu-Zn assemblies. The Cu-Zn alloys could be a potential UBM material for the advanced electronic packaging.