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1
McDonald, Frank Carl. "Specific heat measurements of copper benzoate." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0002844.
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Nishizaki, Shuji. "Specific Heat of the Spin-Triplet Superconductor Sr2RuO4." 京都大学 (Kyoto University), 2000. http://hdl.handle.net/2433/181099.
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Kyoto University (京都大学)0048
新制・課程博士
博士(理学)
甲第8131号
理博第2153号
新制||理||1145(附属図書館)
UT51-2000-F35
京都大学大学院理学研究科物理学・宇宙物理学専攻
(主査)助教授 前野 悦輝, 教授 石黒 武彦, 教授 Sigrist Manfred(シーグリスト マンフレッド)
学位規則第4条第1項該当
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Dahn, Douglas Charles. "Low temperature specific heat of LixNbS2 intercalation compounds." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25563.
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This thesis describes a study of the low temperature specific heat of LiⅹNbS₂, where x is between 0 and 1. Samples were prepared by intercalating lithium into niobium disulfide in electrochemical cells. Structural data obtained by x-ray diffraction are presented. These, together with electrochemical measurements, show that staged phases exist for some values of x. The electronic specific heat of LiⅹNbS₂, is consistent with complete charge transfer from the intercalated lithium to the bands of the NbS2 host. The lattice specific heat also shows large changes as a function of x. A discussion of the data in terms of continuum elasticity theory suggests that intercalation produces large changes in the shear elastic constant C₄₄ . A brief discussion of superconductivity in LiⅹNbS₂, is also included.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Varadarajan, Vijayalakshmi. "SPECIFIC HEAT MEASUREMENTS ON STRONGLY CORRELATED ELECTRON SYSTEMS." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/805.
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Studies on strongly correlated electron systems over decades have allowed physicists to discover unusual properties such as spin density waves, ferromagnetic and antiferromagnetic states with unusual ordering of spins and orbitals, and Mott insulating states, to name a few.
In this thesis, the focus will be on the specific heat property of these materials exhibiting novel electronic ground states in the presence and absence of a field. The purpose of these measurements is to characterize the phase transitions into these states and the low energy excitations in these states. From measurements at the phase transitions, one can learn about the amount of order involved [i.e. entropy: ΔS = ∫Δc p/T dT], while measurements at low temperatures illuminate the excitation spectrum. In order to study the thermodynamic properties of the materials at their phase transitions, a high sensitive technique, ac-calorimetry was used. The ac-calorimeter, workhorse of our low dimensional materials lab, is based on modulating the power that heats the sample and measuring the temperature oscillations of the sample around its mean value. The in-house ac-calorimetry set up in our lab has the capability to produce a quasi-continuous readout of heat capacity as a function of temperature. A variety of single crystals were investigated using this technique and a few among them are discussed in my thesis.
Since many of the crystals that are studied by our group are magnetically active, it becomes useful for us to also study them in the presence of a moderate to high magnetic field. This motivated me to design, develop, and build a heat capacity probe that would enable us to study the crystals in the presence of non-zero magnetic fields and at low temperatures. The probe helped us not only to revisit some of the studied materials and to draw firm conclusions on the previous results but also is vital in exploring the untouched territory of novel materials at high magnetic fields (~ 14 T).
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Glockling, James L. D. "Heat and mass transfer in specific aerosol systems." Thesis, London South Bank University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303937.
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Moran, Joel Patrick. "Specific heats of aqueous lithium bromide solutions." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/16363.
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Polcyn, Adam D. (Adam Daniel) 1970. "Specific heat of Sr₃CuPt₀₅Ir₀.₅O₆ below 1K." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85335.
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Balci, Hamza. "Specific heat and nernst effect of electron-doped cuprate superconductors." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/217.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Physics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Kirkham, Mark. "High temperature specific heat capacity measurement of Ni2+XMn1-XGa." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14416.
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The investigation of Ni2MnGa ferromagnetic shape memory alloys relies on accurate and complete phase diagrams for the various phase transitions these materials exhibit. However, very little work has been performed to investigate the high temperature order/disorder phase transitions. This project tries to fill some of the gap in the phase diagram through a systemic composition based investigation of Ni2-XMn1+XGa (X=-0.2, 0.0, 0.2, 0.8 and 1.0) using high temperature specific heat measurements. The work has produced a phase diagram in the composition range measured and demonstrated that the order/disorder transition temperatures and Curie temperatures follow the predicted trend as seen in similar studies of different alloy compositions. This work has also characterised the melt temperature of the five compositions measured. As part of the investigation of the high temperature phase transitions, a 'High Temperature Adiabatic Calorimeter' was developed, which was commissioned using four reference samples (copper, Stainless steel, graphite and molybdenum). The developed system used a linearly drifting baseline to improve the speed, accuracy and stability of the system. This modification to the standard adiabatic calorimeter measurement scheme required extensive development of the analysis techniques and development of new approaches (e.g. heating phase analysis and finite element modelling analysis). The system was demonstrated to operate well between room temperature and 1350 K, producing accurate specific heat data that compared well with the standard data for the commissioning samples. Due to time constraints this system was not used for the Ni2MnGa investigation.
10
Zhu, Xiaoyi. "Prediction of Specific Heat Capacity of Food Lipids and Foods." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437750532.
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Mohammed, K. A. "Low temperature specific heat measurements of crystalline and amorphous magnetic materials." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356096.
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Lang, Brian E. "Specific Heat and Thermodynamic Properties of Metallic Systems: Instrumentation and Analysis." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/785.
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A small-scale adiabatic calorimeter has been constructed as part of a larger project to study nano-particles and to facilitate specific heat measurements on samples where it is difficult to obtain enough material to run on the current large-scale adiabatic apparatus. This calorimeter is designed to measure sample sizes of less than 0.8 cc over a temperature range from 13 K to 350 K. Specific heat results on copper, sapphire, and benzoic acid show the accuracy of the measurements to be better than ±0.4% for temperatures higher than 50 K. The reproducibility of these measurements is generally better than ±0.25%. Experimental specific heat data was collected on this new apparatus for synthetic akaganeite, β-FeOOH, for samples with varying degrees of hydration. Our results yield values for Δ_0^298.15S°m of 79.94 ±0.20 J•K^-1•mol^-1 and 85.33 ±0.021 J•K^-1•mol^-1 for samples of β-FeOOH0.551H2O and β-FeOOH0.652H2O, respectively. From this data, we were able to determine the standard molar entropy for bare β-FeOOH, as Δ_0^298.15S°m = 53.8 ±3.3 J•K^-1•mol^-1, based on subtractions of the estimated contribution of water from the hydrated species. Additionally, the specific heats of α-uranium, titanium diboride, and lithium flouride have been measured on a low-temperature, semi-adiabatic calorimeter down to 0.5 K. For the α-uranium, the specific heat of a polycrystalline sample was compared to that of a single crystal, and it was found that there was a significant difference in the specific heats, which has been attributed to microstrain in the polycrystal. The third law entropy for the polycrystal at 298.15 K, Δ_0^298.15S°m, calculated from these heat capacities is 50.21 ±0.1 J•K^-1•mol^-1, which is good in agreement with previously published values of polycrystal samples. For the single crystal Δ_0^298.15S°m, calculated using the thermodynamic microstrain model, is 49.02 ±0.2 J•K^-1•mol^-1. The low-temperature specific heats of titanium diboride and lithium fluoride have been measured from 0.5 K to 30 K as part of a larger project in the construction of a neutron spectrometer. For this application, the measured specific heats were used to extrapolate the specific heats down to 0.1 K with lattice, electronic, and Schottky equations for the respective samples. The resultant specific heat values at 0.1 K for TiB2 and 6LiF are 4.08E-4 ±0.27E-4 J•K^-1•mol^-1 and 9.19E-9 ±0.15E-9 J•K^-1•mol^-1, respectively.
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Zink, Barry Lee. "Specific heat and thermal conductivity of thin film amorphous magnetic semiconductors /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3070996.
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Chastin, S. "Low temperature specific heat and thermal conductivity of Kondo intermetallic compounds." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244320.
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Poon, Wai-hei. "The induction of cellular stress responses by specific Kappa-opioid receptor agonist." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31473921.
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YOSHIKAI, YASUNOBU. "Regulatory Role of Heat Shock Protein-specific T Cells in Host Defense." Nagoya University School of Medicine, 1992. http://hdl.handle.net/2237/17519.
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Nyeanchi, Emmanuel Bongkiyung. "Resistivity and specific heat capacity of high Tc superconductors and magnetic materials." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239591.
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Chen, Karen. "Studies on LiYRF." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1561.
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Thesis advisor: Michael GrafSenior thesis on muon spin relaxation study of LiHoXY1-XF4 and semi-adiabatic specific heat experiment on LiTb0.40Y0.60F4
Thesis (BS) — Boston College, 2010
Submitted to: Boston College. College of Arts and Sciences
Discipline: Physics Honors Program
Discipline: Physics
19
Poon, Wai-hei, and 潘偉曦. "The induction of cellular stress responses by specific Kappa-opioid receptor agonist." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31473921.
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Mohamed, Mahmoud. "Physical Properties of Iron-based Superconductors Probed by Low-Temperature Specific-Heat Measurements." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-98736.
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In this thesis, specific heat, magnetic susceptibility and resistivity studies on the iron-pnictide superconductors LiFeAs, NaFe1-xCoxAs, AFe2As2 (A = K, Ca, Ba), M1-xNaxFe2As2 (M = Ca, Ba), and Ca(Fe1-xCox)2Fe2As2 are presented, from which different intrinsic physical properties are resolved. The combined first-order spindensity wave/structural transition which occurs in the parent compounds of the 122 pnictide systems is shown to gradually shift to lower temperature for low doping levels. Upon higher doping, this transition is completely suppressed and simultaneously, superconductivity appears at lower temperature. In contrast, the phase diagram in Ca(Fe1-xCox)2Fe2As2 is shown to exhibit a pronounced region of coexistence of magnetism and superconductivity. Further important results reported in this work concern the electronic properties and superconducting-gap characteristics. In LiFeAs, the zero-field temperature dependence of the electronic specific heat can be well described by two s-wave gaps, whose magnitudes are in agreement with ARPES results. Our gap analysis in KFe2As2, Ca0.32Na0.68Fe2As2, and Ba0.65Na0.35Fe2As2 single crystals also implies the presence of two s-wave-like gaps. The magnetic phase diagram of LiFeAs and KFe2As2 for magnetic fields along both principal orientations has been constructed and an anisotropy of Hc2(T) of 3 and 5, respectively, has been obtained.
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Rodan, Steven. "Nuclear magnetic resonance and specific heat studies of half-metallic ferromagnetic Heusler compounds." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-198412.
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Half-metallic ferromagnets (HMFs), with fully spin-polarized conduction electrons, are prime candidates for optimizing spintronic devices. Many Heusler compounds (a class of ternary and quaternary intermetallics) are predicted to be HMFs, in particular Co$_{2}YZ$ (where $Y$ is usually another transition metal, and $Z$ is an s-p element). Crystal structure is controlled by thermodynamics to a large extent. Ideally, one should be able to control and optimize properties which are of interest by appropriately "tuning" the structure (e.g. annealing), but first one must understand the structure and its relation to observed physical properties. A local structural probe technique such as nuclear magnetic resonance (NMR) is an essential tool for identifying and quantifying the various atomic-scale orderings. Different Heusler structure types and antisite disorders affect the material's physical properties.
In this thesis, order-disorder phenomena in both bulk and thin film samples of Co$_2$Mn$_{1-x}$Si$_x$ and Co$_2$Mn$_{1-x}$Fe$_x$Si have been systematically studied using NMR. Though it is the films which are directly implemented in actual devices, studying bulk samples as model systems provides invaluable information regarding the material properties.
The evolution of local atomic structure in numerous thin films has been shown to depend greatly on preparation parameters, including post-deposition annealing temperature, and specific stoichiometry. For Co$_2$MnSi films, the ideal post-annealing temperature for promoting the $L2_1$ atomic structure was found; the threshold temperature above which structure continues to become higher-ordered in the bulk, but where too much interdiffusion at the buffer interface occurs, degrading the smooth interfaces necessary for high magnetoresistance ratios. NMR also adds evidence that Co$_2$Mn$_x$Si$_{0.88}$ ($x>$1) electrodes in magnetic tunnel junctions have highest tunneling magneto-resistance because the excess Mn suppresses the formation of detrimental Co$_{Mn}$ antisites.
A systematic investigation of several thermal and magnetic properties, including Sommerfeld coefficients, Debye temperatures, saturation magnetic moments, spin-wave stiffness, and magnon specific heat coefficient, were measured for selected Co$_2$-based ternary and quaternary Heusler compounds. Obtained values were compared with theoretical ones calculated using electronic band structure methods. It has been systematically shown that adding a magnon term to the specific heat has a negligible effect on the electronic contribution in all cases.
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Leigh, Nigel Royston. "Specific heat measurements on chevrel phase materials exhibiting coexistence of superconductivity and magnetism." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3849/.
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A probe for measuring the specific heat of superconductors at low temperatures and in high magnetic fields has been built and commissioned. The probe has been tested using the relaxation method on samples of copper and the accuracy of the data is 1.3 % between 5 K and 30 K, data taken using the long range pulse method has a resolution of 10 mK. Specific heat measurements have been performed on members of the series (Pb(_1)-(_x))Cu(_1.8x)Mo(_6)S(_8), (Sn(_1-x))Eu(_x)Mo(_6)S(_8) and (Pb(_1-x)M(_x))Mo(_6)S(_8) where M = Gd and Eu, from 3 K up to 30 K and in magnetic fields up to 15 T. Additional results from resistivity, susceptibility, magnetisation. X-ray diffraction, transmission electron microscopy and electron dispersive-ray measurements are also presented. These data have been compared to results from other authors and are analysed in terms of the BCS and GLAG theories of superconductivity and the magnetic properties of these materials. The mean field model has been used to calculate numerically the magnetic contribution to the specific heat (cm) of both ferromagnetic and antiferromagnetic systems as a function of temperature and applied field both above and below the ordering temperature. In addition an approximate analytic form for the magnetisation has been used to calculate Cm above the ordering temperature. Expressions have been derived for the saturation value of the peak in C(_m): C(^sat)(_m) = 1.1245n(_cell)RJI(J+1) and the temperature dependence of the peak with applied field ȡ(μ(_o)H(_ext))/ȡT(_peak)=6.540/g(_J)(J+1). They allow the simple calculation of the values of J and g(_J)(J + 1) from specific heat data. The magnetic contribution to the specific heat of the samples (Sn(_0.65)Eu(0.35)Mo(_6)S(_8)) and (Sn(0.50)Eu(_0.50)Mo(_6)S(_8)) have been modelled using these calculations and excellent agreement is found by considering the magnetic ions as free ions. The sample is accurately modelled by including an additional minority phase (Gd(_2)S(_3)). The approximate expressions have also been used to analyse data on high temperature superconductors producing values of J and g(_J)}{J + 1) consistent with a doublet ground state. The properties of Chevrel phase materials have been determined as a function of doping level. The critical temperature is degraded by doping but an increase in the critical current density is observed in the series (Pb(_1-x)Cu(_1-8x)Mo(_6)S(_8) for very low levels of doping. Increases of up to 28 % in the upper critical field, that are probably due to the compensation effect and an increase in the normal state resistivity, are also observed in the series (Sn(_1-x)Eu(_x)Mo(_6)S(_8)) at high levels of doping and in the series (Pb(_1-x)Gd(_x)Mo(_6)s(_8) for low levels of doping.
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Kmety-Stevenson, Carmen R. "Phase transitions in molecule-based magnets : neutron diffraction, magnetic and specific heat studies /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343146984.
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Hunt, Andrew Philip. "Heat strain, hydration status, and symptoms of heat illness in surface mine workers." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/44039/1/Andrew_Hunt_Thesis.pdf.
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The aim of the research program was to evaluate the heat strain, hydration status, and heat illness symptoms experienced by surface mine workers. An initial investigation involved 91 surface miners completing a heat stress questionnaire; assessing the work environment, hydration practices, and heat illness symptom experience. The key findings included 1) more than 80 % of workers experienced at least one symptom of heat illness over a 12 month period; and 2) the risk of moderate symptoms of heat illness increased with the severity of dehydration. These findings highlight a health and safety concern for surface miners, as experiencing symptoms of heat illness is an indication that the physiological systems of the body may be struggling to meet the demands of thermoregulation. To illuminate these findings a field investigation to monitor the heat strain and hydration status of surface miners was proposed. Two preliminary studies were conducted to ensure accurate and reliable data collection techniques. Firstly, a study was undertaken to determine a calibration procedure to ensure the accuracy of core body temperature measurement via an ingestible sensor. A water bath was heated to several temperatures between 23 . 51 ¢ªC, allowing for comparison of the temperature recorded by the sensors and a traceable thermometer. A positive systematic bias was observed and indicated a need for calibration. It was concluded that a linear regression should be developed for each sensor prior to ingestion, allowing for a correction to be applied to the raw data. Secondly, hydration status was to be assessed through urine specific gravity measurement. It was foreseeable that practical limitations on mine sites would delay the time between urine collection and analysis. A study was undertaken to assess the reliability of urine analysis over time. Measurement of urine specific gravity was found to be reliable up to 24 hours post urine collection and was suitable to be used in the field study. Twenty-nine surface miners (14 drillers [winter] and 15 blast crew [summer]) were monitored during a normal work shift. Core body temperature was recorded continuously. Average mean core body temperature was 37.5 and 37.4 ¢ªC for blast crew and drillers, with average maximum body temperatures of 38.0 and 37.9 ¢ªC respectively. The highest body temperature recorded was 38.4 ¢ªC. Urine samples were collected at each void for specific gravity measurement. The average mean urine specific gravity was 1.024 and 1.021 for blast crew and drillers respectively. The Heat Illness Symptoms Index was used to evaluate the experience of heat illness symptoms on shift. Over 70 % of drillers and over 80 % of blast crew reported at least one symptom. It was concluded that 1) heat strain remained within the recommended limits for acclimatised workers; and 2) the majority of workers were dehydrated before commencing their shift, and tend to remain dehydrated for the duration. Dehydration was identified as the primary issue for surface miners working in the heat. Therefore continued study focused on investigating a novel approach to monitoring hydration status. The final aim of this research program was to investigate the influence dehydration has on intraocular pressure (IOP); and subsequently, whether IOP could provide a novel indicator of hydration status. Seven males completed 90 minutes of walking in both a cool and hot climate with fluid restriction. Hydration variables and intraocular pressure were measured at baseline and at 30 minute intervals. Participants became dehydrated during the trial in the heat but maintained hydration status in the cool. Intraocular pressure progressively declined in the trial in the heat but remained relatively stable when hydration was maintained. A significant relationship was observed between intraocular pressure and both body mass loss and plasma osmolality. This evidence suggests that intraocular pressure is influenced by changes in hydration status. Further research is required to determine if intraocular pressure could be utilised as an indirect indicator of hydration status.
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Wakelin, Jonathan Peter. "Low temperature specific heat and thermal conductivity of doped YBa2Cu3O7 and other ceramic superconductors." Thesis, University of Sussex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284082.
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Kim, Dongkyun. "Specific heat and magnetization measurements on the ferromagnetic phase transition of manganites and ruthenates /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3044768.
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Parry, Thomas J. "I. Thermodynamics and Magnetism of Cu2OCl2 II. Repairs to Microcalorimeter the "2"s are subscripts, and the second 2 is preceded by a lower case L, not a one." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2609.pdf.
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Koppanooru, Sampat Kumar Reddy. "Estimating Thermal Conductivity and Volumetric Specific Heat of a Functionally Graded Material using Photothermal Radiometry." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062896/.
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Functionally graded materials (FGMs) are inhomogeneous materials in which the material properties vary with respect to space. Research has been done by scientific community in developing techniques like photothermal radiometry (PTR) to measure the thermal conductivity and volumetric heat capacity of FGMs. One of the problems involved in the technique is to solve the inverse problem, i.e., estimating the thermal properties after the frequency scan has been obtained. The present work involves finding the unknown thermal conductivity and volumetric heat capacity of the FGMs by using finite volume method. By taking the flux entering the sample as periodic and solving the discretized 1-D thermal wave field equation at a frequency domain, one can obtain the complex temperatures at the surface of the sample for each frequency. These complex temperatures when solved for a range of frequencies gives the phase vs frequency scan which can then be compared to original frequency scan obtained from the PTR experiment by using a residual function. Brute force and gradient descent optimization methods have been implemented to estimate the unknown thermal conductivity and volumetric specific heat of the FGMs through minimization of the residual function. In general, the spatial composition profile of the FGMs can be approximated by using a smooth curve. Three functional forms namely Arctangent curve, Hermite curve, and Bezier curve are used in approximating the thermal conductivity and volumetric heat capacity distributions in the FGMs. The use of Hermite and Bezier curves gives the flexibility to control the slope of the curve i.e. the thermal property distribution along the thickness of the sample. Two-layered samples with constant thermal properties and three layered samples in which one of the layer has varying thermal properties with respect to thickness are considered. The program is written in Fortran and several test runs are performed. Results obtained are close to the original thermal property values with some deviation based on the stopping criteria used in the gradient descent algorithm. Calculating the gradients at each iteration takes considerable amount of time and if these gradient values are already available, the problem can be solved at a faster rate. One of the methods is extending automatic differentiation to complex numbers and calculating the gradient values ahead; this is left for future work.
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Hollenhead, James B. "A calorimetric study of the immersion of bituminous coal in liquids." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45157.
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The surface properties of coal greatly affect its use
in industrial processes such as gasification, liquefaction
and the use of coal slurries. In addition, such processes
also involve reagent penetration into coal pores and the
oxidative state of the coal surface. Reagent penetration
into coal was examined by determining the heat and kinetics
of immersion of Pocahontas No. 3 coal in water, methanol, a
series of n-alkanes, and several cyclic and heterocyclic
hydrocarbons. Results indicate that the heat of immersion
is sensitive to the carbon chain length of the wetting
liquid and its ability to hydrogen bond to coal. The time
of immersion is insensitive to carbon chain length but is
increased by the presence of nitrogen in a cyclic
hydrocarbon.
The oxidation of both unextracted and extracted coal at
3200C was followed by immersional measurements in water.
The heat of immersion increased rapidly with oxidation time,
leveling off after 3 hours of oxidation. Extraction with
methanol or pyridine prior to oxidation and immersion
lowered the time of immersion in water compared to the
unextracted case. The oxidation of coal was also followed
by x-ray photoelectron spectroscopy (XPS). The XPS
oxygen/carbon ratios correlated linearly with the heats of
immersion for the extracted, oxidized coals. Thus, XPS was
shown to be a useful ancillary technique to heat of
immersion for the study of coal surfaces.
Master of Science
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Babaee, Koochaksaraee Sima, and Sara Ghahremanpour. "Using Design of Experiments in Validation of a new calorimetric method for the specific heat capacity determination." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19555.
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Total Quality Management as a holistic management system is widely practical inevery organization these days and one of the foundations of TQM which should betaken into account in all functions of the company is continuous improvement.Customer satisfaction is an important topic in which continuous improvement play akey role and leads to enhance it. Therefore, it is very worthwhile for the organizationto define the designing new products/methods based on recent and future customerneeds as one of its main activities.Generally, during the development and before launching a new product/method,validation is a useful process to improve the quality and establish the qualification ofthat product/method.This project was conducted to perform a validation for a new calorimetric method byuse of DOE (Design Of Experiments) in “SP Technical Research Institute of Sweden”.The study have presented the results of implementing DOE in such a way that thenew calorimetric method is validated; besides it could determine the best condition inwhich the intended results could be achieved.This thesis is a completion part of the master program in Industrial Engineering with aspecialization in Quality and Environmental Management at University of Borås.
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Tovstyuk, C. C. "Thermodynamic Functions of Electron Gas in Strong anisotropic Materials. Quantum Gas." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42583.
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In this paper we report about the peculiarities of thermodynamic functions of quantum electron gas in layered crystals. In such materials the conductivity along the layers exceeds by several orders the conductivity across layers. To these structures depend layered materials: YTe3, LaTe3, CeTe3, InSe, which are considered at low temperatures, as well as a number of organic conductors. There are many theoretical and experimental papers, indicated coexistence of equipotential energy surfaces of electrons in the form of corrugated cylinders and corrugated sheets. The thermodynamic functions for quantum electron gas are evaluated and compared for two different dependences of energy on momentum. The same parameters are used
in both models – they are effective masses and translation vectors for β - GaSe. Our investigations allowed explaining the temperature dependence of resistivity for strong anisotropic and isotropic crystals at law temperatures, received by experiment. We also analyzed the specific heat in such crystals and explained the anomaly, observed in such crystals and illustrated the imperfection of the Debye model.
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Madden, Marie Catherine. "A non-clinical method to simultaneously estimate thermal conductivity, volumetric specific heat, and perfusion of in-vivo tissue." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34799.
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Many medical therapies, such as thermal tumor detection and hypothermia cancer treatments, utilize heat transfer mechanisms of the body. The focus of this work is the development and experimental validation of a method to simultaneously estimate thermal conductivity, volumetric specific heat, and perfusion of in-vivo tissue. The heat transfer through the tissue was modeled using a modified Pennes' equation. Using a least-squares parameter estimation method with regularization, the thermal properties could be estimated from the temperature response to the known applied heat flux.
The method was tested experimentally using a new agar-water tissue phantom designed for this purpose. A total of 40 tests were performed. The results of the experiments show that conductivity can be successfully estimated for perfused tissue phantoms. The values returned for volumetric specific heat are lower than expected, while the estimated values of perfusion are far greater than expected. It is believed that the mathematical model is incorrectly accounting between these two terms. Both terms were treated as heat sinks, so it is conceivable that it is not discriminating between them correctly.
Although the method can estimate all three parameters simultaneously, but it seems that the mathematical model is not accurately describing the system. In the future, improvements to the model could be made to allow the method to function accurately.Master of Science
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Li, Gang. "Generation of Tumor-Specific Immunity Using HER2/NEU Positive Tumor Derived Chaperone-Rich Cell Lysate (CRCL)." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/193817.
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HER2/neu is an oncogenic tumor-associated antigen over-expressed in several human tumors including breast and ovarian cancer. The selective expression of HER2/neu and its role in epithelial carcinogenesis makes HER2/neu an ideal target for immunotherapy. Tumor-derived chaperone-rich cell lysate (CRCL), containing numerous heat shock proteins, has successfully been used to generate tumor-specific immunity against a wide range of murine tumors and is a great candidate for an effective vaccine against HER2/neu positive tumors. In the first part of this study, the potency of human ovarian cancer-derived CRCL to activate dendritic cells (DCs) and to generate tumor-specific T cells in vitro has been investigated. Chaperone-rich cell lysate was generated from primary ovarian cancer tissues and SKOV3-A2, a HER2/neu, Wilm's tumor gene 1 (WT1) and HLA-A2 positive human ovarian tumor cell line. T cells from healthy donors and from ovarian cancer patients secreted higher amounts of interferon-γ following in vitro re-stimulation with ovarian cancer-derived CRCL compared to HER2/neu or WT1 peptide-pulsed DCs. We were also able to generate cytotoxic T lymphocyte activity against cancer-specific antigens such as HER2/neu and WT1 from all healthy donors, but from only one of the four ovarian cancer patients with bulky disease. In the second part of the study, the potency of tumor-derived CRCL to elicit the humoral immune response against a murine HER2/neu positive tumor (TUBO) has been examined. Vaccination of mice bearing a palpable tumor efficiently delayed the development of the tumor. In the vaccinated mice, CRCL vaccination induced significant anti-HER2/neu antibodies. Using B cell deficient mice and antibody transfer experiments, we have shown that the induction of anti-HER2/neu antibodies is both necessary and sufficient for the anti-tumor effect. Further, we have demonstrated that serum from TUB0 CRCL-vaccinated mice stimulated the internalization of the HER2/neu molecules, resulting in the down-regulation of their surface expression. Moreover, antibody-dependent cellular cytotoxicity has been observed against TUBO cells when presented with sera from vaccinated mice. These results indicate that CRCL may be a potent adjuvant for women suffering from HER2/neu positive ovarian or breast cancer and that this personalized vaccine may be a promising approach for active immunotherapy.
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Schmidt, Joel Edward. "The Use of Ammonium Carbamate as a High Specific Thermal Energy Density Material for Thermal Management of Low Grade Heat." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1310666985.
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Loula, George Dourado. "Estudo das propriedades físicas dos compostos UptSn e U(Cu, Au)Sn." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277787.
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Orientador: Flavio Cesar Guimarães GandraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: Neste trabalho realizamos medidas de difração de raios-X, magnetização, calor específico e resistividade elétrica nos compostos da série U(Cu,Au)Sn, além do composto UPtSn, que pode cristalizar-se tanto na forma hexagonal (sem tratamento térmico) quanto cúbica, com tratamento térmico de 850ºC por uma semana. Na série UCu(1-x)A u(x)Sn verificamos que todos os compostos apresentam ordenamento antiferromagnético, sendo que a temperatura de ordenamento magnético ( TN) decresce com o aumento da concentração do substituinte. Além disso, percebe-se um pequeno aumento no calor especifico eletrônico ( d ) e no volume da célula unitária ao se inserir Au. O momento efetivo do urânio diminui de 3.44 m B para x=0 até 3 m B para x=1, devido a uma maior hibridização 5f-s,d decorrente da substituição do Cu por Au. Essa hibridização propicia diversas alterações nas propriedades físicas dos compostos. Quanto ao sistema UPtSn, verificamos que o tratamento térmico ao qual a amostra é submetida influencia na formação estrutural do composto e as propriedades físicas de cada estrutura são muito distintas. A fase cúbica ordena antiferromagneticamente em 35K e o urânio apresenta momento magnético efetivo igual a 3.24 m B, enquanto que a fase hexagonal ordena ferromagneticamente em 27K, e apresenta momento magnético efetivo de 2.82 m B. Esta redução no momento efetivo pode ser devida ao efeito Kondo, mas os resultados experimentais não são conclusivos quanto a isto
Abstract: In this work we report on measurements of x-ray diffraction, magnetization, specific heat and electrical resistivity for the series U(Cu,Au)Sn and for UPtSn, which crystallize either with hexagonal (as-cast) or with cubic simmetry (annealed). In the series UCu(1-x)Ausub(x)Sn we verify that all the compounds order antiferromagnetically and the magnetic ordering temperature (TN) decreases when the substitute's concentration is increased. We also noticed a small increase of the electronic specific heat coefficient and unit cell volume by replacing Au for Cu. The effective moment is reduced from 3.44 m B at x=0 to 3 m B at x=1 due to a more effective 5f-s,d hybridization. This hybridization is responsible for the phisical properties of these compounds. For UPtSn we found that the thermal treatment can define the structure of the compound. The phisical properties of both compound are quite different. The cubic phase is AF with TN = 35K and present m eff = 3.24 m B while the hexagonal phase orders at 27K with m eff = 3B. Such reduction of the effective moment may be due to the Kondo effect but the experiments where not conclusive about this
Mestrado
Física da Matéria Condensada
Mestre em Física
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Klein, Markus. "Single-Zone Cylinder Pressure Modeling and Estimation for Heat Release Analysis of SI Engines." Doctoral thesis, Linköping : Department of Electrical Engineering, Linköping University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9863.
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Mášová, Pavla. "Možnosti regulace vneseného tepla - experimentální ověření." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229977.
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This diploma thesis elaborated within the Manufacturing Technology Master´s study program considers various possibilities of welding which can regulate the amount of inputted heat into the welded joint. For experimental testing, material X2CrTi12 (ferritic stainless steel) was chosen, welded by means of methods suitable for the material. Welding methods included TIG, plasma, and laser. Further possibilities of heat input are suggested, such as pulse welding, Rapid, Fast Root, Surface Tension Transfer, Cold Metal Transfer, ColdArc, and Wise. The aim of the experiment is to compare the amount of heat input and its effect on particle growth and hardness.
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Ali, Salamat. "Specific heat measurements using the A.C. technique on the chevrel phase superconductor Pb(_1-x)Gd(_x)Mo(_6)S(_8) in high magnetic fields." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5284/.
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We have developed a probe to measure specific heat of Gd-doped PbMo(_6)S(_8), at low temperatures in high magnetic fields up to 12.5 T using a heat pulse method and an a.c. technique. Comparison between these heat capacity measurements and transport measurements provides critical complimentary information about fundamental thermodynamic properties and granularity m superconductors. We have used a tiny, robust, highly sensitive and broadly field independent Cemox thermometer (CX-1030), eliminating the use of bulky gas thermometry or capacitance thermometry. The diameter of the probe is 20 min which facilitates use in our 17 T high field magnet and in free-standing cryostats. Experiments include accurate measurement of temperature oscillations of 10(^-6)K. The measurements and analysis of the data were made fully computer controlled. Measurements on Cu and NbTi demonstrate we achieved an accuracy of ±0.2 K in temperature and a typical accuracy of -10% m the specific heat values quoted. Gd-doped Lead Chevrel phase material Pb(_1-x)Gd(_x)Mo(_6)S(_8) has been fabricated in a controlled environment using simple sintering methods and a Hot Isostatic Press (HIP) operating at pressures up to 2000 atmospheres. Cp has been measured and the properties of the materials including B(_c2)(T) have been determined. HIP processing improves the materials, increasing Tc ~ 15 K and B(_c2)(0) ~ 60 T. These values are amongst the best reported values for the Chevrel phase materials to date. I am personally responsible for taking all the data and its analysis. The modification of the probe were also undertaken by me. The fabrication of the samples was not my work
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Lopes, Valerio Hayles Vivian. "The Treatment of Indians and Women as the Other in Ruth Prawer Jhabvala’s Heat and Dust: : Olivia’s and the Nawab’s Experiences of Discrimination as the Primary Reason for Their Mutual Attraction." Thesis, Högskolan Dalarna, Engelska, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28117.
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Djurkovic, Borko. "Specific Heat of Unconventional Superconductors." Thesis, 2010. http://hdl.handle.net/10012/5687.
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PrOs₄Sb₁₂ is the first known heavy fermion superconductor containing Pr. Many experiments show results indicating unconventional superconductivity in this system. Most notably, PrOs₄Sb₁₂ exhibits two superconducting transitions. The upper transition occurs at Tc₁ ≈ 1.89 K and the lower transition occurs at Tc₂ ≈ 1.72 K. There are many features of this system that are not understood and do not have a unifi ed consensus among researchers. Many issues remain unanswered, such as the origin of superconductivity, symmetry of the superconducting energy gap, and the nature of the two superconducting transitions. We present specific heat data for a single PrOs₄Sb₁₂ crystal. The data show two superconducting transitions. Variance in the lower superconducting transition (among various samples) suggests multiple superconducting phases. Power law dependence of the low temperature specific heat is indicative of asymmetric energy gap.
Cuprates are unconventional high temperature superconductors. The theory on origin and characteristics of superconductivity in these systems is still a debated issue. Experiments indicate presence of a phase in these systems that occurs above the superconducting transition temperature which exhibits some common characteristics with the superconducting state. An important issue is the nature of this so-called "pseudogap" phase and its relationship to the superconducting state. We have developed an experimental apparatus and procedure for measuring the specific heat of a high temperature superconductor and demonstrated it by measuring the heat capacity of a YBCO high-Tc superconductor sample.
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Lin, XI Chan Moses H. W. "Specific heat of solid ⁴He." 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2859/index.html.
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Yi-ChenTseng and 曾意真. "Electronic specific heat of graphites." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/24906962587030845769.
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碩士國立成功大學
物理學系碩博士班
100
Abstract In this paper, we use the tight-binding model to study the density of states (DOS), the chemical potential, and the electronic specific heat of graphite. Different stacking sequences are taken into consideration, including monolayer, AA-, AB-, and ABC-stacked configurations. The different geometric structures result in the various energy bands. The band symmetry and degeneracy also reflect in the density of states and chemical potential, and thus affect the temperature-dependence of electronic specific heat. The energy bands of monolayer graphite (graphene) present a complete symmetry with respect to the Fermi level where two linear bands intersect. As a result, the DOS at the Fermi energy and the chemical potential are both zero, and the electronic specific heat is proportional to the square of the temperature. The energy bands of AA-stacked graphite are also symmetric about the Fermi level with more overlapping between linear bands. The DOS at the Fermi energy is therefore a considerable value, while the chemical potential hardly changes with the temperature. Its electronic specific heat is in direct proportion to the temperature. As for AB-stacked graphite, the energy bands are asymmetric, and the double degeneracy occurs on H-layer. Consequently, it reveals less symmetry in the DOS, and the chemical potential decreases with the increasing temperature. The electronic specific heat at low temperatures can be described by a linear relation, but such relationship no longer exists at high temperatures. The conduction and valence bands of ABC-stacked graphite show slight symmetry with two intersections of linear bands above and below the Fermi level on K- and H-layers respectively. The DOS is symmetric, the chemical potential rises with the temperature, and the specific heat is roughly proportional to the square of the temperature.
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Ke, Cheng-Wen, and 柯誠文. "Specific heat and magnetism of MnxSi." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/85962802517684867653.
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碩士國立交通大學
物理研究所
101
We have measured the specific heat of MnxSi single crystals with the various manganese contents (x = 0.998, 0.981, 0.961, 0.945). We classified the magnetic transition features. The first kind has only one peak. The other kind have one sharp peak and a broad peak at higher temperature. The Debye temperatures and the γ have been calculated by fitting the specific heat from 100 K to 200 K. We subtract the electron and phonon contributions to obtain the purely magnetic contribution. Then, we calculated the magnetic entropy difference between these two types of compounds. We compared current results to the specific heat of the LiCu2O2 and the magnetic structure model provide by S.W. Huang et al. (Physical Review Letters 101, 077205(2008) ) and to the study of MnSi by S.V. Grigoriev et al.(Physical Review B 79, 144417(2009) ) and A. Bauer et al.(Physical Review B 85, 214418(2012) ). We discuss what physical mechanism is in the magnetic transitions.
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Kang, Yu-Ching, and 康玉清. "Specific heat studies on NaxCoO2‧yH2O superconductor." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/99475673063296322149.
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碩士國立中山大學
物理學系研究所
92
Since the discovery of high superconducting transition temperature in layered copper oxides, many researchers have searched for similar behavior in other layered metal oxides, such as cobalt and nickel. The sodium cobalt oxyhydrate is the first cobalt-oxide layered superconductor. We present the studies of low-temperature specific heat C(T, H) in NaxCoO2‧yH2O (x ~ 0.35, y ~ 1.3). At H = 0, a very sharp anomaly was observed at T ~ 4.7 K indicating the existence of bulk superconductivity. There exists an αT2 term in C(T, H=0) in the superconducting state manifesting the line nodal superconducting order parameter. The feature at the superconducting transition is rather sharp, becoming broad and strongly suppressed in an applied magnetic field. The transition temperature also changed in an applied magnetic field. Thus an abrupt change of slope in H vs. Tc curve was observed. Possible scenarios such as the multiple phase transitions in the mixed state are discussed.
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Chen, Kuen-He, and 陳昆河. "Specific heat of anharmonic oscillators in one dimension." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/96425039922746733773.
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碩士國立交通大學
物理研究所
88
The specific heats of one-dimension systems are obtained with two different methods, which are achieved in terms of the partition function and the probability density function, respectively. In this thesis, we consider three kinds of anharmonic potentials and calculate numerically the specific heat of a particle moving in a potential in one dimension and also at thermally equilibrium with a heat bath. From the views of classical statistical mechanics, the method from the partition function is standard, direct and simple. In addition, we construct the probability density function of a stochastic variable. Since we can calculate < V > / T and < V > / T , this method can gives us more information. Namely, we can realize the specific heat more deeply. For a symmetric double-well potential, V , we find that at very low temperature the curve of the specific heat has a peak. In addition, we also respectively calculate the specific heats of a symmetric single-well potential, V , and an asymmetric single-well one, V . After comparing the specific heats of these three potentials, we interpret the specific heats of them from the view of the geometry of these potentials. In V and V , we find that there is a region in the potential where the potential curvatures are negative. Finally we suggest that the peak of the specific heat of a one-dimension system, once it appears, is associated with the existence of negative curvature of the potential.
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Huang, Chien-Hsun, and 黃建勳. "Specific Heat of Molten Salt Embedded with NanoParticles." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12481835014841901078.
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碩士國立交通大學
機械工程學系
100
Molten salts are extensively used as a thermal energy storage material in solar-thermal power plants nowadays. The energy storage capacity of a solar-thermal power plant is restricted by the specific heat capacity of the molten salt. In this work, the effect of concentration and size of the nanoparticles on the specific heat capacity of the molten salt embedded with the nanoparticles (named as nano-salt) was studied. The nano-salts having alumina nanoparticles of two different sizes (13 nm and 90 nm) and three volume concentrations (1.1 %、3.3 % and 5.4 %) were synthesized. Experimental results show that the specific heat capacity of the nano-salt decreases as the volume concentration increases. Meanwhile, the nano-salts doped with 90 nm alumina nanopartilces have a larger specific heat capacity than that of nano-salts doped with 13 nm alumina nanoparticles. In addition, the predictions from the current existing models have a large difference from the experimental data. Thus, a modified model considering the nanolayer effect on the specific heat capacity of the nano-salt was proposed. The prediction based on this modified model agrees better with the experimental data as compared to the existing models.
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Ho, Ming-Xi, and 何明析. "Enhancement of Specific Heat Capacity and Heat Transfer Performance of Nano-Nitrate Salt Eutectics." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/65urb4.
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博士國立清華大學
工程與系統科學系
106
Both solar thermal and nuclear power systems are important energy options with low carbon emissions. Molten salt has been proposed as the working fluid in a concentrating solar power system, and it is also suggested to be employed in a molten salt reactor, which is one of six types of Generation-IV power systems. Molten salts present feature of high heat capacity and high thermal stability. Nevertheless, molten salts usually exhibit relatively poor heat transfer performance and non-uniform temperature distribution. Besides, the specific heat capacity of molten salts is not as high as water and there is a need for the enhancement. This study demonstrates the variation of specific heat capacity and heat transfer performance in the molten salt doped with nanoparticles. Innovative apparatus and procedures have been developed to prepare the specimen of molten salt with high quality. Moreover, a series of thermal-physical characteristics, including melting point, decomposition temperature, thermal diffusivity, thermal conductivity and specific heat capacity for a pure fluoride salt (FLINAK) and a nitrate salt (HITEC) are measured and compared with that reported in the literature to validate the specimen prepared. At first, this work studied the effect of alumina nanoparticles (mean diameter about 40 nm) concentration on the specific heat capacity of molten HITEC salt, which is called nano-HITEC. The nano-HITEC salt in this study is free of surfactant and an innovative preparation process and sampling apparatus for molten nano-HITEC have been established in the present study to avoid the possible precipitation of nanoparticles. The specific heat of molten HITEC and nano-HITEC are measured using a power compensated differential scanning calorimeter (DSC) at the Industrial Technology Research Institute (ITRI) of Taiwan. A power compensated DSC monitors the endothermic or exothermic reaction of specimen under a constant heating rate to determine the specific heat capacity of specimen. In this work, an optimal concentration of 0.063 wt.% is identified, demonstrating the highest enhancement on the specific heat capacity of 19.9%. Lower or higher concentration of nanoparticles tends to reduce the enhancement. For the concentration of 2 wt.%, the negative effect of doping the nanoparticles on the specific heat capacity appears for all temperatures in the present study. The SEM images after solidification of samples reveal that near uniform dispersion of nanoparticles with negligible agglomeration for the concentration smaller than 0.016 wt.%. The agglomeration becomes significant and the particle clusters seem to be inter-connected for higher concentrations. Moreover, this study conducts a statistical analysis on the number of isolated particles and number and size of clusters using SEM images to develop a simplified model, which describes the area of particle-liquid interface of nano-HITEC fluid with different concentration. The results indicate that the agglomeration of nanoparticles occurs as the concentration is over 0.023 wt.%; clusters with different sizes are formed and the total area of isolated particles is decreased and the clusters begin to contribute to the total interfacial areas with the overall area decreasing at the beginning. The minimum particle-liquid interface take place at concentration of 0.048 wt.%. Subsequently, the total interfacial area increases with increasing concentration. It is found that the optimal concentration is corresponding to approximately the concentration that the contribution of isolated nanoparticles and particle clusters, size ranging from 0.2 to 0.6 μm, to the interfacial area are approximately the same. The interfacial phenomena at the particle (isolated or cluster) fluid interface is proposed in the literature to be the primary reason for the enhancement of specific heat capacity in nano-salts. Subsequently, the effect of nanoparticle concentration on the laminar convective heat transfer performance for molten nano-HITEC fluid in a mini-circular tube is investigated. An innovative piston driven molten salt apparatus and preparation process of molten HITEC nanofluild are developed to prevent the precipitation of nanoparticles during the measuring process. The piston molten salt pump provides steady flow through the test section which the channel diameter and length are 2.1 mm and 120 mm, respectively. The mean heat transfer of molten salt flow can be evaluated by Newton’s cooling law based on the inlet/outlet temperature and three wall temperatures measured at three axial locations. The results demonstrate that the measurement of mean Nusselt number of the pure HITEC fluid in this study be in good agreement within ±10% with a well-known correlation. A concentration of nanoparticles of 0.25 wt.% in the nano-HITEC, which can be maintained uniform dispersion for about 30 minutes, results in the maximum enhancement of mean Nusselt number of 11.6%. On the other hand, a concentration of 0.063 wt.% provides 9.2% enhancement on the mean Nusselt number of HITEC nanofluid, and precipitation phenomenon is not observed within an hour. In addition, a new correlation with consideration of particle concentration for the laminar convective heat transfer performance of the nano-HITEC fluid in the present minichannel is developed, by which more than 93.9% of the experimental data can be predicted within ±10% of deviation. A nano-HITEC fluid with concentration of 0.063 wt.% of alumina particle of about 40 nm demonstrates best enhancements of its specific heat capacity of 19.9% as well as near best heat transfer performance in this study. This suggests that nano-HITEC of 0.063 wt.% of nano alumina particles of about 40 nm may serve as a working fluid for applications in a thermal storage system or a concentrating solar power system.
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洪大軒. "Superconductivity, Specific heat and Magnetic Properties in CeRu2 Nanoparticles." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/92756310186815189589.
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碩士輔仁大學
物理學系
92
CeRu2 is a type Ⅱ superconductor with a superconduting transition temperature TC = 6 K. Its peak effect in magnetization was attributed to the pinning centers in the specimen. Applying the technique of Excimer laser ablation specimens of nanoparticle were fabricated. The X-ray diffraction patterns of nanoparticles not only showed the broadening of diffraction peaks, but also exhibited the increase of the lattice constant. From the measurements of magnetic susceptibility and heat capacity, the superconductivity in nanoparticles was observed with TC near that of the bulk. In nanoparticles a low-temperature anomaly was observed and was confirmed to be a Kondo effect through the measurements of heat capacity under magnetic field. The superconductivity in the bulk was suppressed from 6 K to 0.9 K as magnetic field up to 8 T. However the superconductivity (TC= 5.95 K) in nanoparticles hardly be influenced by the magnetic field even with the field up to 8 T. In magnetic susceptibility the occurrence of Meissner was observed at 4.5 K with a field as small as 100 G. The result of (T) which is different from that of C(T) may be the characteristic of magnetic properties of nanoparticles. A possible reason is that the contribution of paramagnetism in nanoparticles smears the diamagnetism of superconductivity. The existence of superconductivity in nanoparticles can be explained by the competition of Kondo interaction,electronic energy level splitting and the energy gap of superconductivity .
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陳伯仲. "Superconductivity, specific heat and magnetic properties in CeCo2 nanoparticles." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/96982280556011619242.
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碩士輔仁大學
物理學系
92
In this thesis we studied the correlation of superconductivity, magnetism and heat capacity with the size in CeCo2. As the size decreases to nanoscale the fraction of surface atoms increases dramatically and the influence of the surface effect on physical properties becomes significant. In the meantime the electronic band structure become broaden and more discreteness. Bulk CeCo2 is a superconductor with Tc = 1.2 K. However the superconductivity disappears as the size of CeCo2 is reduced to 5.8nm - 14nm. The consequence is just as suggested by P. W. Anderson, the superconductivity will no longer exist when the electronic energy level splitting is larger than the energy gap of superconductivity. It is also observed that the lattice constant shrinks with the decrease of sample size. From the measurements of heat capacity, the electronic state of Ce was changed from intermediate valence into trivalence as particle size decreased. An occurrence of Kondo anomaly was also observed in nanoparticles. The Kondo anomaly was confirmed by the peak shifting to higher temperature with the increase of magnetic field. An important result was also found in heat capacity, that was the Kondo temperature and the volume fraction of Ce3+ declined as the particle size decreased. Based on the measurements of magnetic susceptibility it was kwon that the effective moment μB in nanoparticles was larger than that in the bulk.
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Li, Hsiao-Hsun, and 黎孝勳. "Specific Heat Studies on the Electron-doped Superconductor Pr1.85Ce0.15CuO4." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/31180598047408373255.
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碩士國立中山大學
物理學系研究所
89
In this thesis we synthesize Pr1.85Ce0.15CuO4 system by mean of X-ray diffraction, electrical resistivity, magnetic susceptibility and low-temperature specific heat. From these data analysis, we hope to more clearly understand the transition of electron-doped superconductor Pr2-xCexCuO4 (0.14