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Vasquez, Erick S. "Rheological, thermal and processing studies of perfluorocyclobutyl (PFCB) polymers." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1247509068/.
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May, Nathanael Henderson. "A Morphological Study of PFCB-Ionomer/ PVdF Copolymer Blend Membranes For Fuel Cell Application." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76853.
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A new material for use as a proton exchange membrane in fuel cells has been developed: a blend of a perfluorocyclobutane-based block ionomer (S-PFCB) and Poly (vinylidene-co-hexafluoropropylene) (Kynar Flex, KF). This thesis details the work done thus far to characterize the morphology of this material, using small angle x-ray scattering, differential scanning calorimetry, atomic force micrscopy, and some other techniques to a lesser extent.
Small angle x-ray scattering (SAXS) of pure S-PFCB showed a strong block copolymer- associated phase separation, on the order of 25 nm. Differential scanning Calorimetry (DSC) confirmed this finding. SAXS also revealed the presence of a peak representing individual ionic aggregates on the order of 3 nm. Finally, it was shown with DSC that no crystallinity develops in the S-PFCB block copolymer, while one of the blocks, known as 6F, crystallizes extensively.
SAXS of incremental blend compositions of KF and S-PFCB revealed a steady increase in size of the block copolymer phase separation peak in SAXS, demonstrative of the miscibility of KF and the non-sulfonated 6F block of S-PFCB. Furthermore, this incremental study determined the scattering vector range relevant for comparing amounts of KF crystallinity. DSC of incremental blend compositions revealed two phases of KF crystallinity develops upon cooling a membrane, independent of cooling rate.
Atomic force microscopy (AFM), small angle x-ray scattering (SAXS), and differential scanning calorimetry (DSC) corroborate to suggest a nonuniform morphology through the thickness of solution cast membranes. Also, the effect of different casting temperatures and after-casting anneals on morphology was assessed.
Future work on this project involves morphological studies at various relative humidities and temperatures, as well as following up on discoveries already made. Finally, transmission electron micrscopy (TEM) should be performed to provide a visual analog, which will greatly help in developing an accurate morphological model.Master of Science
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Rojo, Duran Sergio. "Synthèse d’ionomères par polycondensation directe de monomères fonctionnels." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1294/document.
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Ce manuscrit de thèse décrit la synthèse et la caractérisation d'ionomères conducteurs protoniques pour une application en tant que membrane pour pile à combustible. La stratégie adoptée pour la synthèse de ces polymères repose sur la polycondensation directe de monomères fonctionnels. Pour ce faire, et dans le cadre d'un travail important de chimie organique, la synthèse de trois monomères sulfonés ainsi que de trois monomères phosphonés a été réalisée. Différents polymères perfluorés (polyperfluorocyclobutane (PFCB) et polyaryléthers (PAE) (Polyétheréther cétone (PEEK) et Polysulfone (PS), ont été obtenus par polycondensation directe de ces monomères fonctionnalisés. Il a été possible de synthétiser des copolymères séquencés (à blocs) et comportant un ou deux types de fonctions conductrices protoniques. Afin d'établir d'éventuelles relations structure-propriété pour ces polymères et l'influence du solvant dans la morphologie de la membrane, une étude de la morphologie a été réalisée à partir de plusieurs séries de polymères PAE et leurs analogues « statistiques ». Les valeurs de conductivité des polymères à blocs sont, en général, supérieures à celles de leurs analogues « statistiques ». Un PAE obtenu est particulièrement intéressant, il possède à la fois une conductivité (216 mS.cm 1) nettement supérieure au Nafion® et un gonflement plus faible. Le polymère perfluoré (PFCB) obtenu est également très prometteur : la conductivité enregistrée pour ce ionomères est de 138 mS/cm. Ce travail de thèse est, à notre connaissance, le premier exemple de synthèse d'un PFCB sulfoné par polymérisation directe d'un monomère fonctionnel mais il constitue également le premier exemple de synthèse de poly(aryléther)s à blocs sulfonés / phosphonés par copolymérisation directe de deux types de monomères fonctionnelsThis thesis describes the synthesis and characterization of proton conducting polymers for application as membrane for fuel cells (PEMFC). The approach for the synthesis of polymers consists in creating polymers from direct polycondensation of functional monomers, in order to better control their final IEC. Three sulphonated monomers and three phosphonated monomers have been first synthetized. Different types of polyarylethers (one of them is both sulphonated and phosphonated) and one perfluorinated polymer (PFCB) have been synthetised by direct polycondensation of functional monomers. In order to explain the influence of the solvent in the final morphology of the membrane, and the relation between its structure and properties, one morphological study has been realized to the obtained polymers but also to their analogues “statistical” polymers. In general, the blocks polymers obtained the highest values of conductivity. One polyarylether seems particularly interesting, because its conductivity value is much higher than Nafion®’s, and has a smaller swelling value. The perfluorinated polymer has also an interesting conductivity value (138 mS/cm). This thesis work is, to the best of our knowledge, the first example of the synthesis of a sulphonated PFCB obtained by direct polycondensation but also the first example of synthesis of a both sulfonated/phosphonated polyarylethers by direct copolymerisation of to types of functional monomers
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Osborn, Angela Michelle. "Investigation of Phase Morphology and Blend Stability in Ionomeric Perfluorocyclobutane (PFCB)/Poly(vinylidene difluoride) (PVDF) Copolymer Blend Membranes." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/77265.
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This research is focused on the investigation of phase morphology and blend stability within ionomeric perfluorocyclobutane (PFCB)/poly(vinylidene difluoride) (PVDF) copolymer blend membranes. The morphologies of these unique materials, designed as proton exchange membranes (PEMs) for proton exchange membrane fuel cells (PEMFCs), have been examined not only in the as-cast/as-received state, but also as a function of exposure to various ex-situ aging environments. The morphological investigations used to probe the response of these ionomer blends have been designed to mimic the environment within a PEMFC and will therefore enhance our understanding of the implications of morphological changes which may occur during fuel cell operation.
Thermal annealing of the membranes has been conducted to determine the materials' morphological response to various temperatures in the absence of hydration. The results of these thermal annealing studies have facilitated the isolation of morphological contributions stemming from thermal exposure. Immersion of the blend membranes in liquid water has allowed for singular identification of the role of hydration in the blend membranes' morphological rearrangement and phase stability. However, as the typical fuel cell environment to which these membranes will be exposed is complicated by the presence of both temperature and humidity, our ex-situ investigations have also included the exposure of PFCB/PVDF copolymer blend membranes to simultaneous thermal annealing and hydration conditions – a treatment we refer to as "hygrothermal aging." This unique procedure serves as a simplified method whereby the complex fuel cell environment may be simulated, and the resultant morphological response researched.
While the work presented herein has enhanced our understanding of the blend stability of the specific membranes investigated, we have also advanced the fundamental knowledge of the role of morphology with respect to the fuel cell performance of blend materials and the corresponding implications of morphological rearrangements. Such an understanding is essential in the development of morphology-property relationships and eventual optimization of membrane materials designed for use in fuel cells.Ph. D.
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Finlay, Katherine A. "Characterization of Sulfonated Perfluorocyclobutane /Poly(Vinylidene Difluoride)-co-Hexafluoropropylene (PFCB/PVDF-HFP) Blends for Use as Proton Exchange Membranes." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/47475.
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The research herein focuses on the characterization of a PFCB/PVDF-HFP (70:30 wt:wt) blend fuel cell membrane including the constitutive and morphological properties, how these properties predict the stresses incurred under fuel cell operating conditions, and how these properties change over time under fuel cell operating conditions. Characterization was performed to mimic temperature and moisture conditions found in operating fuel cells to understand how these materials will behave in service. This included thermal and hygral expansion, mass uptake, and the stress relaxation modulus. These constitutive properties were chosen for characterization such that a model could be created to predict the stresses incurred during fuel cell operation, and examine how these stresses may change under different operating conditions and over time. Based on the results of this model, lifetime predictions were made resulting in recommendations to further extend the operating time of this membrane beyond the DOE 5000 hr requirement. Stress predictions are useful, however if the material properties are changing over time under the fuel cell operating conditions, they may no longer be valid. Therefore, PFCB/PVDF-HFP membranes were conditioned for different amounts of time under conditions similar to those commonly found in operating fuel cells. These conditioned membranes were then characterized and compared with solvent exchanged membranes, the same materials used for previous material characterization. The properties examined included stress relaxation modulus, bi-axial strength, mass uptake, water diffusion, and proton conductivity. To further understand any changes noted in these properties after different environmental exposures, morphological analysis was performed. This included small angle x-ray scattering, infrared spectroscopy, transmission electron microscopy, and differential scanning calorimetry.
It was initially found that the proton conductivity decreased severely when the material was immersed at high temperatures over short time periods. This was consistent with changes noted in other properties, and morphological analysis showed a decrease in the ionic network as well as an increase in the phase separation of the PFCB block copolymer as well as the PVDF-HFP crystallinity. These large morphological changes could be very detrimental while in service, resulting in early termination of the fuel cell. However, it was also noted that if these materials are annealed at high temperature (140"C), the negative property changes are abated. This abatement is again tied to the morphology of the material, as annealing the material at high temperature creates stronger physical crosslinks, and induces a small amount of chemical crosslinking via condensation of the sulfonic acid groups, thus allowing the stress predictions performed earlier to have greater validity. Therefore, it is important to not only understand the properties of a material during characterization, but also the underlying polymer structure, and how this structure can change over time, as all of these items control the long term material performance while in service.
Ph. D.
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Siuta, Chase Michael. "Measuring Material Properties of Proton Exchange Membranes using Pressure Loaded Blister Testing and Digital Image Correlation." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76858.
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The strength and durability of proton exchange membranes for use in fuel cells has received much attention recently due to the increased push for sustainable alternatives to the internal combustion engine. To be viable, these alternatives must have comparable lifetimes and power outputs to the internal combustion engines they replace. Chemical degradation was once viewed as the most common culprit of early fuel cell failure, but as membranes and catalysts improved, mechanical failure became an important factor. As a result, fundamental research on the mechanically-induced failure mechanisms of fuel cell membranes, coupled with development and processing of less expensive membranes, has become an important topic. The use of the blister test geometry, along with digital image correlation of the deformed shape, creates a self-contained analysis tool useful for measuring the biaxial strength of membranes. In this work, blister tests are used to measure biaxial stress and strain for fuel cell membranes subjected to ramped pressure loading to form stress-strain curves that indicate the onset of yielding under biaxial stress conditions. Stress-life curves are developed experimentally for Gore-Selec? series 57 members using data collected under constant pressure conditions. These results are used to predict blister failure under ramped and fatigue loadings. A newly implemented hydrocarbon membrane system is evaluated with constant-pressure-to-leak blister testing. Improved strength following an isothermal hold at 100°C (pretreatment) is shown to occur. Ramped pressure testing indicates that the material after the pretreatment is stiffer and has a higher yield stress than the material before treatment. Morphological and constitutive characterization indicated differences in the materials that are consistent with the improved performance.Master of Science
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Addo, Isaac D. "Diazonium 4-(trifluorovinyloxy) Perfluorobutanesulfonyl Benzenesulfonimide Zwitterionic Monomer Synthesis." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3137.
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3-Diazonium- 4-(trifluorovinyloxy) - perfluorobutanesulfonyl benzenesulfonimide zwitterionic monomer (see figure 1) is proposed to be polymerized and further act as a new electrolyte for Polymer exchange membrane fuel cells (PEMFCs). One reason is that, the aromatic trifluorovinyl aryl ether (TFVE) group can easily be homopolymerized to aromatic perfluorocyclobutane (PFCB) polymer. Furthermore, the diazonium moiety in the monomer is expected to covalently attach the electrolyte to the carbon electrodes support. The perfluoroalkyl(aryl) sulfonimide (PFSI) pendant provides good chemical and mechanical stability as well as better proton conductivity. Several multi-step synthetic schemes are designed to obtain such monomer from perfluoroalkyl(aryl) sulfonimide (PFSI). Among them, the purified coupling product 4-OCF2CF2Br-3-NO2-PhSO2(M) SO2C4F9 from the first approach was successfully completed. The next stages of the work will involve dehalogenation, reduction, and diazotization to achieve the targeting monomer. All the intermediates were characterized by 1H and 19F NMR and FT-IR spectroscopy.
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Li, Bo. "Development of polymer nano/micro-systems as contrast agents for ultrasound molecular diagnosis of cardiovascular pathologies." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD017/document.
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Les maladies cardio-vasculaires liées à l'athérosclérose sont pourvoyeuses d’une importante morbi-mortalité dans les pays développés. Une détection plus précoce des modifications des parois vasculaires, via des techniques de diagnostic non invasives, pourrait sensiblement améliorer leur prise en charge. L'échographie est largement utilisée comme outil de dépistage des maladies cardiovasculaires. Cependant, sa faible sensibilité limite son utilisation. Le développement d’agent de contraste spécifique permettant de résoudre ce problème semble donc primordial. Le fucoidane est un ligand polysaccharidique sulfaté ayant une forte affinité pour la P-sélectine. Exprimée au niveau de la surface des plaquettes activées et des cellules endothéliales, cette dernière est impliquée dans la pathogénèse précoce des maladies cardiovasculaires. Le but de ce projet de thèse a été de développer un agent de contraste injectable ciblant la P-sélectine via le fucoidane dans le but de réaliser une modalité d’imagerie moléculaire de faible coût, simple et spécifique des pathologies artérielles. Trois types d'agents de contraste ont été développés : 1) Des nanoparticules associées à du bromure de perfluorooctyle (PFOB), fonctionnalisées par du fucoidane. Elles ont été capables de se fixer à la P-selectine et une amélioration du contraste a été observée présentaient une mauvaise échogénicité dans la circulation sanguine, probablement en raison de leur faible teneur en PFOB et de leur très petite taille. 2) Afin d’améliorer l’échogénicité, des microcapsules contentant du PFOB dans leur coeur ont été développées. Celles-ci se sont également liées à la P-sélectine même en condition de dans un modèle animal de maladie artérielle. Cependant, ces produits flux sanguin. Des résultats dans les zones où la P-sélectine était exprimée. Malheureusement, l'augmentation du ont montré que ces m icrocapsules étaient présentes contraste était toujours insuffisante pour être suffisamment discriminante. 3) Des microbulles fonctionnalisées par du fucoidane, ont été conçues pour surmonter ce problème d’échogénicité. Elles ont montré une augmentation significative du signal acoustique en condition de flux sanguin. De plus, ces microbulles se sont accumulées à la surface des parois artérielles riches en thrombus. Ces derniers résultats indiquent que ces microbulles, en tant qu'outil d'imagerie moléculaire ultrasonore, pourraient être très intéressantes pour les futures études des maladies artériellesCardiovascular diseases due to atherosclerosis remain a major morbidity in developed countries. Their treatment could be substantially improved with early detection of the vascular Ultrasonography is widely used as a screening tool in clinic to detect cardiovascular diseases. However, its low resolution requires the development of targeted acoustic tracers to improve the contrast degree. Fucoidan is a sulfated polysaccharide ligand with a high affinity for P-selectin, which was found to be expressed on the activated non- pathological changes by invasive diagnostic techniques. platelets and endothelial cells and involved in the early pathogenesis of cardiovascular diseases. The aim of this doctoral project was to develop injectable, low-cost and simple contrast agents, functionalized with fucoidan as efficient acoustic tracers of P-selectin for ultrasound molecular imaging of arterial pathologies. Three types of contrast agents have been developed: 1) Fucoidan functionalized nanoparticles loaded with perfluorooctyl bromide (PFOB). They could bind to P-selectin and exhibit contrast enhancement in animal models of arterial disease. However, these products showed poor echogenicity in blood stream due probably to low content of PFOB and their very small size. 2) Fucoidan functionalized microcapsules with PFOB core were developed to improve the PFOB encapsulation efficiency. They could bind to P-selectin in arterial flow conditions, and microcapsules were located in the regional expression of P-selectin. Unfortunately, results revealed that these the contrast enhancement was still insufficient to be observed. 3) To address echogenicity problems, fucoidan functionalized polymer microbubbles were designed to replace PFOB. They showed strong signal enhancement under flow conditions and could accumulate on the surface of platelets-rich thrombus. These results indicated that these microbubbles, as ultrasound molecular imaging tools, could be very interesting for the future study of arterial diseases
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Kantzon, David. "PFC-design for frequency converter." Thesis, Linköpings universitet, Fysik och elektroteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-124547.
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This thesis deals with power factor correction for three-phase systems. A boost-buck topology was described, modeled and then simulated in MATLAB/Simulink. The simulation results show that the system provides a power factor over 99% over the tested power output range. Moreover, the harmonic injection concept was introduced which reduces the total harmonic distortion to 8.72% at full output power. A prototype system was also built using an FPGA for the control system. The prototype did not provide the performance seen in simulation but showed that the method is valid and does provide a higher power factor when used.
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Bignold, Simon M. "Optimisation of the PFC functional." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/80984/.
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In this thesis we develop and analyse gradient-fl ow type algorithms for minimising the Phase Field Crystal (PFC) functional. The PFC model was introduced by Elder et al [EKHG02] as a simple method for crystal simulation over long time-scales. The PFC model has been used to simulate many physical phenomena including liquid-solid transitions, grain boundaries, dislocations and stacking faults and is an area of active physics and numerical analysis research. We consider three continuous gradient fl ows for the PFC functional, the L2-, H-1- and H2-gradient fl ows. The H-1-gradient flow, known as the PFC equation, is the typical flow used for the PFC model. The L2-gradient flow is known as the Swift-Hohenberg equation. The H2-gradient ow appears to be a novel feature of this thesis and will motivate our development of a line search algorithm. We analyse two methods of time discretisation for our gradient fl ows. Firstly, we develop a steepest descent algorithm based on the H2-gradient fl ow. We further develop a convex-concave splitting of the PFC functional, recently proposed by Elsey and Wirth [EW13], to discretise the L2- and H-1-gradient flows. We are able to prove energy stability of both our steepest descent algorithm and the convex-concave splitting scheme of [EW13]. We then use the Lojasiewicz gradient inequality (first developed in [ Loj62]) to prove that all three schemes converge to equilibrium. For numerical simulations we undertake spatial discretisation of our schemes using Fourier spectral methods. We consider a number of implementation issues for our fully discrete algorithms including a striking issue that occurs when the number of spatial grid points is low. We then perform several numerical tests which indicate that our new steepest descent algorithm performs well compared with the schemes of [EW13] and even compared with a Newton type scheme (the trust region method).
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Kirchner, Marie-Therese [Verfasser], Florian [Akademischer Betreuer] Pfab, and Johannes [Akademischer Betreuer] Ring. "Akupunktur im Vergleich zu Antihistaminika bei experimentellem Juckreiz bei Patienten mit atopischem Ekzem / Marie-Therese Kirchner. Gutachter: Florian Pfab ; Johannes Ring. Betreuer: Florian Pfab." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1047440660/34.
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Kirchner, Marie-Therese Verfasser], Florian [Akademischer Betreuer] Pfab, and Johannes [Akademischer Betreuer] [Ring. "Akupunktur im Vergleich zu Antihistaminika bei experimentellem Juckreiz bei Patienten mit atopischem Ekzem / Marie-Therese Kirchner. Gutachter: Florian Pfab ; Johannes Ring. Betreuer: Florian Pfab." München : Universitätsbibliothek der TU München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20131030-1131492-0-9.
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Miller, Daniel [Verfasser]. "Optimierung einer eingangsgleichrichterlosen Leistungsfaktorkorrekturschaltung (PFC) / Daniel Miller." München : Verlag Dr. Hut, 2018. http://d-nb.info/1156510481/34.
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Schiff, Albrecht Johannes. "Optimised PFC circuits for efficient power conversion." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611141.
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Matejov, Michal. "Pasivní PFC filtry pro spínané napájecí zdroje." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217598.
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This work deals with theory of switched power sources. There is description of the ways for connection and their practice purposes. In the next parts there are defined requirements on input supply circuit for these sources, especially for the form of output current. There are mentioned the basic connecting methods of PFC circuits and these methods modify the output current to meet the requirements of specification ČSN EN 61000- 3- 2. In the next parts there are shown simulations of PFC circuits made by Pspice application. Further is the basic description of sources construction for the sources which were used for testing and measuring. The final part deals with evaluation of the measuring on the chosen computer’s source. It compares between the manufacturer’s solutions and PFC circuit made by ourselves.
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Knorst, Tarcísio. "Aplicação da tecnologia PFCP integrada ao CAPP em ambiente de ferramentaria /." Florianópolis, SC, 1998. http://repositorio.ufsc.br/xmlui/handle/123456789/77889.
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Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico.Made available in DSpace on 2012-10-17T08:25:54Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T00:50:07Z : No. of bitstreams: 1 147126.pdf: 3809383 bytes, checksum: 1407a1efec58ec3840c76547782764cb (MD5)
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Livingstone, Phil. "Nicotinic modulation of dopaminergic signalling in the PFC." Thesis, University of Bath, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528111.
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Sartori, Hamiltom Confortin. "Uma nova metodologia de projeto para otimização do volume do converosr boost PFC." Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/8466.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThis work investigates the influence of operation point (Δi @ fs) in the final volume of PFC boost converter. The boost inductor, EMI filter and thermal heatsink are the elements which main influences in the converter volume. These elements are strongly influenced by the chosen operation point, showing a direct relationship among them. With the increase of switch frequency and of the input current ripple occurs reduction of the boost inductor volume. On the other hand, it increases the switching losses in semiconductors, and influence on the EMI filter volume. It should be highlight that the optimum designs of individual devices or parameters of a system could not take the optimization of the overall system. In this form it is strongly recommended that the engineers and designers take into account the overall system, as well available technologies, standard and recommendation, and finally market commitments. The methodology presented realize the converter design in a integrate form, selecting the operation point that the converter finds the minimal total volume, starting from input variable output power, input and output voltage. The design takes into account different semiconductors technologies, different input filter topologies, different heart sinks profile, different magnetic cores technologies further of international standards that the converter must be adapt. Based on an integrate design of converter parameters is possible optimize the design finding the operation point for the minimal volume.
Esse trabalho investiga o impacto do ponto de operação (Δi @ fs) no volume final do conversor boost operando como pré regulador com correção do fator de potência (PFC). Os elementos de maior influência no volume do conversor são o indutor boost, o filtro de entrada e os dissipadores térmicos. O volume destes elementos é diretamente influenciado pelo ponto de operação, mostrando uma relação direta entre eles. Com o aumento da freqüência de comutação e da ondulação da corrente de entrada ocorre a diminuição do indutor boost, porém, aumentam as perdas nas comutações dos semicondutores e aumenta o volume do filtro de entrada. Com a diminuição da freqüência e da ondulação da corrente ocorre o inverso, sabendo disto, fica claro que projetar individualmente cada um destes três elementos pode resultar em um bom projeto individual, contudo penaliza os outros parâmetros. Assim, a metodologia apresentada realiza o projeto do conversor de forma integrada, escolhendo o ponto de operação em que o conversor encontre o volume final mínimo, partindo de algumas variáveis de entrada, como potência de saída e tensões de entrada e saída. O projeto leva em consideração diferentes tecnologias de semicondutores, topologias de filtros de entrada, perfis de dissipadores térmicos, tecnologias de núcleos magnéticos além das normas internacionais a que o conversor deve se adequar. Baseado no projeto integrado dos parâmetros do conversor é possível otimizar o projeto encontrando o ponto de operação para o volume total mínimo do conversor.
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Douix, Suzie. "Caractérisation de perfluorocarbones (CₓFᵧ, PFCs) par spectrométrie de masse et spectroscopie VUV." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS523/document.
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Les composés perfluorés possèdent des propriétés à la fois hydrophobes et lipophobes et sont commercialisés depuis les années 1950. Ils ont été depuis largement utilisés dans de nombreuses applications industrielles. Cependant, il s’agit de composés persistants, bioaccumulatifs, avec de grandes durées de vie atmosphérique. Ces espèces sont considérées comme de puissants gaz à effet de serre, et seraient principalement dégradées par photolyse, dans la haute atmosphère. Un travail de caractérisation physicochimique de deux composés perfluorés, le PFOA et le PFOS, produits de dégradation ultime des composés perfluorés les plus utilisés, a été réalisé. Des expériences de spectroscopie VUV et spectrométrie de masse ont permis d’identifier les voies de relaxation de ces composés après photoactivation. Une méthodologie par couplage rayonnement synchrotron/spectrométrie de masse permettant la mesure de sections efficaces absolues a été développée puis appliquée aux composés d’intérêt. Ces mesures ont ensuite été reliées à leur taux de photolyse et durées de vie atmosphérique selon l’altitudePerfluorocarbons compounds have both hydrophobic and lipophobic properties. They have been manufactured since the 1950s, and widely used in many industrial applications. However, they are persistent, bioaccumulative compounds with long atmospheric lifetimes. They are considered to be potent greenhouse gases, and are supposed to be mainly degraded by photolysis in the upper atmosphere. A work of physicochemical characterization of two perfluorinated compounds was realized on the PFOA and PFOS. They have been found to be the final compounds of degradation of the majority of perfluororinated compounds. VUV spectroscopy and mass spectrometry experiences have been undertaken to identify their relaxation pathways after photoactivation. A methodology based on the coupling of synchrotron radiation and mass spectrometry was developed to perform absolute cross section measurements and was apply to the compounds of interest. These measurements have been used to determine their photolysis rates and atmospheric lifetimes according to the altitude
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Zhou, Bo. "CCM Totem Pole Bridgeless PFC with Ultra Fast IGBT." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/51120.
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The totem pole PFC suffers from the Mosfet body diode reverse recovery issue which limits this topology adopted in the CCM high power condition. As the ultra-fast IGBT which is capable of providing 100 kHz switching frequency is available in the market, it is possible to apply the totem pole PFC in CCM high power condition. The thesis provides a method by implementing the ultra-fast IGBT and SiC diode to replace the MOSFET in this topology.
To verify the method, a universal CCM totem pole PFC is designed and tested. The design adopts the ADP1048 programmable digital PFC controller by adding external logic gate for totem-pole PFC. ADP1048 greatly simplifies the design process and satisfies the design requirements. The experiment results verify that the totem-pole PFC can be applied into CCM high power condition by using the method. The DC output voltage is well regulated. The power factor is higher than 0.98 when the load is above 400W. The measured efficiency can achieve up to 96.8% at low line and 98.2% at high line condition with switching frequency 80 kHz.Master of Science
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Schwanz, Thiago Guilherme. "RESÍDUOS DE PESTICIDAS E COMPOSTOS PERFLUORADOS EM ÁGUAS: AVALIAÇÃO DA EXPOSIÇÃO DA POPULAÇÃO ATRÁVES DO CONSUMO." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/3412.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorContamination of water resources has been caused great impact to the environment. The water constitutes the greatest source of food, and its value for health is incalculable. Despite this, the presence of contaminants in water for consumption in Brazil is a topic with few researches and sources of information. The main contamination of drinking water takes place directly by man, by the abusive use of pesticides or environmental contaminants, with high bioaccumulation potential in the environment, such as perfluorinated and organochlorine compounds. These compounds are present in water in trace levels, and appropriate analytical methods in order to demonstrate the suitability of method, ensuring the reliability of the results are needed. This study presents two multi-residue methods for determination of perfluorinated compounds (PFCs) and for the determination of pesticides in samples of tap water, bottled water and groundwater collected in Brazil, Spain and France. For PFCs was used solid phase extraction automated "in line" method with direct injection of the sample coupled to mass spectrometry with detection limits between 0.15 and 8.76 ng/L, and the determination of pesticides has been carried out by solid phase extraction and analysed using different techniques of separation and ionization LC-ESI-MS/MS, GC-MS/EI and GC-MS/NCI, with detection limits between 1.02 and 48.21 ng/L. The obtained results showed that the tap water have high concentrations of PFCs, especially in Brazil, with an average of 15.83 ng/L, followed by Spain and France with 15.33 and 7.73 ng/L, respectively. For pesticide analyzes, the data found demonstrate that the groundwater obtained in Brazil showed the highest concentrations of investigated contaminants in comparison with tap and bottled water. Regarding the risk of exposure by ingestion through drinking water, PFCs represent greater danger (estimated at 54.8, 58.0 and 75.6 ng/person per day in Spain, France and Brazil) in relation to pesticides (10.23, 29.40, 30.11 ng/person per day in Spain, France and Brazil, respectively). However, despite the levels found in the investigated countries, the consumption of drinking water does not poses imminent risks to contamination associated with PFCs and pesticides.
A contaminação dos recursos hídricos tem causado grande impacto para o meio ambiente. A água constitui-se na maior fonte de alimentação humana, e seu valor para a saúde é incalculável. Apesar disso, a presença de contaminantes em águas para o consumo no Brasil é um tema pouco pesquisado e com escassas fontes de informação. As principais contaminações nas águas potáveis ocorrem diretamente pela ação do homem, através do uso abusivo de agrotóxicos ou por contaminantes ambientais, com alta capacidade de bioacumulação no meio ambiente, como os compostos perfluorados e organoclorados. Estes compostos estão presentes nas águas em níveis de traços, portanto, metodologias analíticas adequadas, a fim de demonstrar que o método é apropriado, garantindo a confiabilidade dos resultados são necessários. Este estudo apresenta dois métodos multirresiduais para determinação de compostos perfluorados (PFCs) e para determinação de agrotóxicos em amostras de água de torneira, água engarrafada e água subterrânea coletadas no Brasil, Espanha e França. Para os PFCs foi utilizado o método de extração em fase sólida automatizada em linha com a injeção direta da amostra acoplada a espectrometria de massas, com limites de detecção entre 0,15 e 8,76 ng/L. Já a determinação de agrotóxicos foi realizada a partir de extração em fase sólida e análise por técnicas distintas de separação e ionização, LC-ESI-MS/MS, GC-MS/EI e GC-MS/NCI, com limites de detecção entre 1,02 e 48,21 ng/L. Os resultados obtidos demonstraram que as águas de torneira apresentam alta concentração de PFCs, especialmente no Brasil, com média de 15.83 ng/L, seguidos pela Espanha e França com 15,33 e 7,73 ng/L, respectivamente. Para as análises de agrotóxicos, os dados encontrados evidenciam que as águas subterrâneas obtidas no Brasil apresentaram as maiores concentrações dos contaminantes investigados, em comparação com as águas de torneira e águas engarrafadas. Em relação ao risco de exposição pela ingestão através do consumo de água, os PFCs representam um perigo maior (estimado em 54,8, 58,0 and 75,6 ng/indivíduo por dia na Espanha, França e Brasil) em relação aos agrotóxicos (23,10, 29,40, 30,11 ng/indivíduo por dia na Espanha, França e Brasil, respectivamente). Contudo, apesar dos níveis encontrados, em nenhum dos países investigados, o consumo de água potável coloca em risco iminente a contaminação associada a PFCs e agrotóxicos.
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Lange, André De Bastiani. "Retificador PFC monofásico PWM bridgeless três-níveis de alto desempenho." Florianópolis, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/100858.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia ElétricaMade available in DSpace on 2013-06-25T23:20:04Z (GMT). No. of bitstreams: 1 307896.pdf: 8014354 bytes, checksum: e7f5c5f26cf0e245f5bbdc82d9fe7865 (MD5)
Este trabalho apresenta uma nova topologia de retificador monofásico com fator de potência e rendimento elevados, com o objetivo de adaptar-se aos requisitos de sistemas de conversão modernos. O conversor se caracteriza por integrar as etapas de retificação e conversão CC-CC em um único estágio e por operar com três níveis de tensão para o controle da corrente de entrada. A estrutura possibilita a redução das perdas em condução e de comutação, bem como a redução do volume de dispositivos magnéticos. Uma operação eficiente do retificador é obtida com uma técnica de modulação adequada, também foco deste trabalho. Duas técnicas de controle para o retificador foram analisadas e implementadas em um controlador digital de sinais de baixo custo. Uma análise de estabilidade é apresentada para a técnica de autocontrole de corrente considerando-se os efeitos dos atrasos de transporte da implementação digital. Um novo controlador adaptativo e metodologia de projeto são propostos para permitir a operação do conversor em ampla faixa de variação de carga utilizando esta técnica. A verificação experimental é realizada através de um protótipo de 3 kW desenvolvido em laboratório, para o qual se utilizou uma metodologia de projeto que minimiza o volume de material magnético utilizado no indutor boost.
This work presents a novel single-phase rectifier topology with high power factor and high efficiency, aiming to fulfil modern conversion systems requirements. This converter is characterized by integrating the rectifying and DC-DC conversion stages into a single stage and operates with three voltage levels for controlling the input current. The topology enables low conduction and commutation losses and reduced volume of magnetic devices. Efficient rectifier operation is achieved with a suitable modulation technique, which is also within the focus of this work. Two control techniques for the rectifier have been analysed and implemented in a low-cost digital signal controller. A stability analysis is presented for the current self-control technique considering the effects of the transport delays found in the digital implementation. A new adaptive compensator and design method are proposed to allow the converter to operate with wide load variation range using this technique. Experimental verification is performed with a 3 kW labprototype employing a boost inductor optimized design that minimizes magnetic material volume.
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Koh, Hyunsoo. "Modeling and Control of Single Switch Bridgeless SEPIC PFC Converter." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/34125.
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Due to increasing concerns on the power quality, power factor correction (PFC) has become an important issue in light-emitting diode (LED) lighting applications. A boost converter is one of the most well-known PFC topologies, due to its simple circuitry, simple control scheme and small number of passive components. Even though a boost converter is recognized as a typical PFC converter, its output voltage must be higher than its input voltage. This feature is disadvantageous because the device requires an additional buck-stage for LED lighting systems.
As an alternative to the boost converter, a single-ended primary-inductor converter (SEPIC) allows output voltage to be lower or higher than the input voltage. Thus, the SEPIC converter is gaining popularity as a LED driver because it does not require additional power conversion stage. However, designing a controller to meet stability requirements and international standards is quite challenging for SEPIC converters. Additionally, if the digital controller is adopted for its built-in communication features, creating a digitally controlled SEPIC converter would be even more challenging.
This thesis focuses on the state-space averaging modeling of the SEPIC PFC converter and the design of controllers based on both analog and digital controls with precise modeling. The proposed SEPIC converter incorporates RC damping circuits to avoid the instability, and
thus the entire SEPIC converter becomes a 5th order system. Such a high-order system model was derived mathematically and verified with circuit simulator modeling. After verification of the circuit model, the controller was designed with analog transfer functions and converted to and the discrete domain for digital controller implementation. A 150-W single-switch bridgeless SEPIC PFC converter prototype was built accordingly to verify the design. In addition to the current loop controller design for stability, a feed-forward compensator for is introduced and derived for better waveform quality. Simulation results and experiment results are also presented to verify the complete controller with feed-forward compensation. The Texas Instruments (TI) digital signal processor (DSP) TMS320F28335 was adopted for digital controller implementation. For comparison purpose, the TI UC3854 controller was implemented to verify the analog controller design results.Master of Science
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Pfab, Thiemo [Verfasser]. "Genetische und epigenetische Risikofaktoren für kardiovaskuläre Erkrankungen bei Schwangeren und ihren Kindern / Thiemo Pfab." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2009. http://d-nb.info/1023783533/34.
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El, Maiss Janwa. "Conception des matériaux à faible énergie de surface : une nouvelle étape pour la production durable." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4073.
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Les matériaux à faible énergie de surface (LSEMs) sont conçus pour différentes applications. Parmi celle-ci, les applications sur un support solide pour l’élaboration de surfaces superhydro/oléophobes ainsi qu’à l'interface de 2 milieux distincts pour la synthèse de nouveaux tensioactifs éco-responsables. Actuellement, ces matériaux sont constitués essentiellement de composés fluorés pour leurs propriétés uniques leur conférant à la fois l’hydro- et oléo-phobie ainsi que pour leur stabilité thermique et chimique dans des milieux corrosifs. Ce projet montre que l’élaboration des surfaces superhydro/oléophobes peut être réalisée sans utiliser nécessairement des chaînes perfluorées. Deux approches sont adoptées dans ce processus. La première stratégie est d'étudier l'influence de la longueur de la chaîne fluorée sur la structuration et la mouillabilité de la surface des dérivés du ProDOT. La seconde est d'explorer l'influence d'une chaine hydrocarbonée incorporée au coeur des monomères et d'étudier l'effet du type et de la longueur de ces chaînes sur les propriétés de surface. Dans le cadre de l'application des LSEMs sur les ‘matériaux mous’, deux études ont été réalisées : la première se focalisant sur l'effet de la longueur des chaînes hydrocarbonées sur les tensioactifs hybrides à courte chaine fluorée et la deuxième étudiant l'effet de la tête polaire. Deux séries de sulfates et bisulfates hybrides ont donc été synthétisées et leurs propriétés physico-chimiques étudiées. Ce travail a abouti à des résultats intéressantsTwo types of Low surface energy materials LSEMs can be recognized; those which are firstly applied on solid surfaces to elaborate superhydro/oleophobic surfaces that are micro and nano structured, and secondly at the water/air interface to synthesize new ecofriendly surfactants. LSEMs are essentially made from fluorinated compounds due to their unique properties of being both hydro and oleophobic as well as, their thermal and chemical stability in corrosive media. This project shows that the creation of superhydrophobic materials with high oleophobic properties does not necessarily require the utilization of long and bioaccumulative perfluorocarbon chains. Two approaches were adopted in this field. The first strategy was to develop ProDOT derivatives bearing short fluorinated chains to study the influence of the fluorinated chain length on the surface wettability. The proceeding part was to explore the effect of the introduction of a hydrocarbon tail and study the effect of their type and chain length on the surface properties. Another important aspect of this research involves the application of LSEMs on soft materials like surfactants as alternatives to toxic perfluorinated homologues. This study was done to explore the effect of the variant hydrocarbon chains with a short fluorinated tail of hybrid surfactants as well as the effect of the polar head. In this area, two families of hybrid sulfate and bisulfates were synthesized. Their physico-chemical properties were investigated and interesting results were obtained
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Miko, Radoslav. "Třífázový síťový napaječ s aktivním usměrňovačem." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242035.
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Diploma thesis deals with problems of power factor correction and total harmonic distortion of line current in three phase industrial power supplies. It focuses mainly on using of single phase active PFC topologies based on the principle of step up converter, which are applicable to three phase systems. Verification of operation and comparison of parameters of several circuits was done by simulation in program Matlab Simulink. Then for selected circuit of active PFC was done complete design. The result is a prototype of single phase active PFC circuit with an output power 2 kW for input voltage range from 180 to 528 V (47 – 63 Hz) and a prototype of three phase active PFC circuit with an output power 6 kW for input voltage range from 3 x 180 to 3 x 528 V (47 – 63 Hz).
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AlShehab, Ali Saeed. "Development and analysis of high-frequency, high-density PFC power conversion." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/106076.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.Cataloged from PDF version of thesis. "September 2015."
Includes bibliographical references (pages 83-85).
This thesis explores the design of power converters that deliver isolated low-voltage dc output (~24V) and operate from "universal" ac input voltage (85 - 264 Vac RMS). It is important that these converters have good overall efficiency (~90-95%), and good ac line power factor (>0.9, and ideally >0.95) to better utilize the available energy. This thesis looks into achieving high efficiency, high power factor, low voltage stresses, and smaller component sizes by utilizing high frequency operation. The research focuses on component and subsystem evaluation, development and testing as a part of many-person research in this space. The thesis presents a literature based study on current PFC circuit designs and tradeoffs. It also introduces a specific PFC architecture, which provides a low dc output voltage drawing energy from a wide range ac input voltage while maintaining a high power factor. The architecture includes two stages: The first is a "Power Factor Correction" (PFC) which functions as an input stage drawing energy from a wide-range input current. It uses a resonant transition inverted (RTI) buck converter topology to step down the voltage from line voltage (85 - 264 Vac RMS) to around 72V. Furthermore, the inductor for the RTI buck is analyzed. The middle stage is an energy buffer to provide the required energy level for twice line frequency energy buffering and 20ms of energy hold up. The capacitor requirements, analysis, and selection are explored and developed. The second stage is a transformation and regulation stage which also provides electrical isolation between the ac input and dc output. The thesis also explores the use of available conventional high-density telecom "brick" converters as a second stage. In conclusion, the project explores the possibility of using a buck configuration for the PFC, sacrificing the ability to use high energy density 400V capacitors while gaining the advantage of using the high-density telecom brick converters and different output voltage options.
by Ali Saeed AlShehab.
M. Eng.
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Mallet, Géraldine-Mary. "La liaison en français : descriptions et analyses dans le corpus PFC." Paris 10, 2008. http://www.theses.fr/2008PA100172.
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La liaison en français est un phénomène qui s’étend sur différents niveaux d’analyse et qui, pour cette raison, est problématique. La première partie de cette thèse s’attache à décrire ces différentes dimensions impliquées dans le processus (phonologique, morpho-syntaxique, sociolinguistique, lexicale), pour montrer en quoi cette diversité est constitutive du phénomène et qu’on ne peut pas réduire la liaison à une dimension particulière. Dans la seconde partie, nous nous appuyons sur une étude empirique fondée sur une utilisation de la base PFC (Phonologie du Français Contemporain). Cette partie présente la description du protocole, la collecte et l’exploitation des données. La dernière étape de ce travail consiste à proposer une caractérisation de la liaison qui rend compte des contradictions relevées dans la première partie, en s’appuyant sur une véritable base empirique. De cette façon, nous montrons que si la liaison est fréquente, elle concerne néanmoins des classes réduites de mot et nécessite une analyse formes par formes, sans exclure un certain nombre de généralisations locales qui constituent le caractère innovant de ce travailThe French liaison is a complex phenomenon manifested in many different levels of analysis. The first part of the thesis is an overview of the various dimensions involved in the process: phonologic, morpho-syntactic, sociolinguistic, lexicon. The goal of this overview is to show that the multidimensionality is proper to the liaison phenomenon and that the descriptive diversity can not be reduced to a single, specific dimension. The second part is an empirical study based on the Phonology of Contemporary French corpus and database. It contains the description of the protocol, data collection and data processing. The last part carries out a liaison analysis which, standing on a solid empirical fundament, takes into account the contradictions outlined in the first part. The study shows that regardless of its frequency, the liaison affects entire word categories (classes) and requires a form-by-form analysis, yet allowing for certain amount of local generalizations which constitute the scientific contribution of this thesis
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Huang, Weixing. "Design of a Radial Mode Piezoelectric Transformer for a Charge Pump Electronic Ballast with High Power Factor and Zero Voltage Switching." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31818.
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In a conventional electronic ballast for a fluorescent lamp, inductor-capacitor-transformer
tank circuit is used. A Piezoelectric Transformer (PT) can potentially be used
to replace such a tank circuit to save space and cost. In the past, ballast design using a PT
requires selecting a PT from available samples which are normally not matched to
specific application and therefore resulting in poor performance. In this thesis, a design
procedure was proposed for designing a PT tailored for a 120-V 32-W electronic ballast
with high power factor, high efficiency and Zero-Voltage-Switching (ZVS) of the
inverter transistors that drive the lamp. This involves selection of PT materials,
determination of geometries and the number of physical layers of the PT. A radial mode
piezoelectric transformer prototype based on this design process was fabricated by Face
Electronics Inc. and was tested experimentally, the results showed that the ballast using
this custom-made PT achieved high power factor, Zero-Voltage-Switching and a 83%
overall efficiency.Master of Science
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Sang, Tingting. "Integrated Electro-thermal Design Methodology in Distributed Power Systems (DPS)." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9678.
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Although suitable CAD tools for thermal and electrical analyses in power electronic systems are available, traditional stand-alone simulation method seldom takes into consideration of the inter-dependency of semiconductor device power loss and junction temperature in an iterative process. However these dependencies are important, especially for applications where both cooling and power losses are driven by complex mechanisms.
For a power supply system, a dynamic design process is necessary to address both electrical and thermal issues. It is because the steady state temperatures of the system are obtained from loss-and-temperature iteration. Once a system solid body model is built, iterations between power loss and junction temperature calculations are performed to obtain the steady state temperature distribution. Since reliability and failure rate of components are directly related to temperatures, an accurate model is critical to provide proper thermal management, which achieves maximum power density. All cooling-related data such as placement of components, airflow rate, heat sink size, and device types are subjected to design changes in order to meet ultimately the temperature requirements.
The goal of this thesis is to demonstrate the benefits of integrated analysis and design tools applied in distributed power supply systems designs. First, it will significantly speed up the design process and eliminate the errors resulting from repeated manual data entry and information exchange. Second, the integrated electrical-thermal design tools encompass electrical, thermal, layout, and packaging design to obtain the optimal system design.Master of Science
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Pfob, Christian Helmut [Verfasser]. "3D Dosimetrie mit PET und SPECT im Vergleich zu konventioneller 2D Dosimetrie / Christian Helmut Pfob." München : Verlag Dr. Hut, 2018. http://d-nb.info/1162767170/34.
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Goosey, Emma Rae. "Towards understanding the fate of perfluoroalkyl compounds (PFCs) within urban environments : implications for human exposure." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1052/.
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Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have been detected across the globe in a variety of media. The toxicity of these compounds and other precursors has led to concern about human exposure. The purpose of this thesis is to investigate the presence of perfluoroalkyl compounds (PFCs) in UK indoor and outdoor microenvironments and the impact this may have on human exposure. Both PFOS and PFOA were chosen for analysis (via LC-ESI-MS/MS) because of their highly persistent behaviour. Additionally, perfluorohexane sulfonate (PFHxS), was chosen along with precursors to PFOS and PFOA; perfluorooctane sulfonamides (PFOSAs) and perfluorooctane sulfonamidoethanols (PFOSEs). An international comparison of house dust was conducted and concentrations of PFCs in the UK (except for ethyl perfluorooctane sulfonamide (EtFOSA)) were found to be similar to those from France, Germany, USA, Canada and Australia and much greater than from homes in Kazakhstan and Thailand. Concentrations of EtFOSA were significantly higher in house dust samples from Australia compared to the UK, and were raised in all other countries. The reason for this is uncertain, but is speculated to derive from the use of EtFOSA as an active ingredient in Sulfluramid, which is an insecticide used for control of ants, cockroaches and termites.
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Kunacheva, Chinagarn. "Study on Contamination of Perfluorinated Compounds (PFCs) in Water Environment and Industrial Wastewater in Thailand." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/85390.
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PFCs are used in a wide variety of industrial and commercial applications for more than 50 years. Among variation of PFCs, Perfluorooctane sulfonate (PFOS) (CF3(CF2)7SO3-) and perfluorooctanoic acid (PFOA) (CF3(CF2)6COO-) are the most dominant PFCs. In May 2009, PFOS, its salts and perfluorooctane sulfonyl fluoride (PFOSF) are designated as new Persistent Organic Compounds (POPs) which are resistant, bio-accumulating, and having potential of causing adverse effects to humans and environment (IISD, 2009). However, products containing PFCs are still being manufactured and used, which could be the main reason why they are still observed in the environment and biota (Berger et al., 2004; Saito et al., 2003; Sinclair et al., 2004). The study is focused on the PFCs contamination in water and industrial wastewater around the Central and Eastern Thailand, where is one of the major industrialized areas in the country. The samplings were conducted in major rivers, Chao Phraya, Bangpakong and Tachin River. PFCs were contaminated in all rivers. The average total PFCs were 15.10 ng/L, 18.29 ng/L and 7.40 ng/L in Chao Phraya, Bangpakong and Tachin River, respectively. PFOS and PFOA were the predominant PFCs in all samples. The total of 118.6 g/d PFOS and 323.6 g/d PFOA were released from the three rivers to the Gulf of Thailand. The survey was also conducted in small rivers, reservoirs, and coastal water around Eastern Thailand, where many industrial zones (IZ) are located. The geometric mean (GM) concentration of each PFC was ranged from 2.3 to 107.7 ng/L in small rivers, 2.2 to 212.2 ng/L in reservoirs, and 0.8 to 41.1 ng/L in coastal water samples. The higher PFCs contaminations were detected in the surface water around the industrial zones, where might be the sources of these compounds. Field surveys were also conducted in ten industrial zones (IZ1 – IZ10) to identify the occurrences of PFCs from in industries. The recovery rates of PFCs in the samples indicated that the matrix interference or enhancement was an important problem in PFCs analysis. The elevated concentrations were detected in electronics, textile, chemicals and glass making industries. Total PFCs concentrations in the influent of WWTP were ranged from 39.6 to 3, 344.1 ng/L. Ten industrial zones released 188.41 g/d of PFCs. All of the treatment processes inside industrial zones were biological processes, which were reported that they were not effective to remove PFCs. The influence of industrial discharges was affected not only the rivers and reservoirs but also in the coastal water. The PFCs in rivers and reservoirs were discharged to the Gulf of Thailand, which is the important food source for Thai people and exports. Due to the problems in industrial wastewater analysis, several optimizing options were applied in PFCs analytical method especially in Solid Phase Extraction (SPE) procedure. The combination of PresepC-Agri and Oasis®HLB was the better option for analyzing PFCs in water samples. The optimum flow rate for loading the samples was 5 mL/min. Methanol (2 mL) plus Acetronitrile (2 mL) was the effective way to elute PFCs from the cartridges. The specific solvent percentages to elute each PFCs were identified for both water and industrial wastewater samples. The matrix removal methods by using Envi-Carb and Ultrafilter were effective for different types of industrial wastewater samples. PFCs were detected in surface waters, which are the sources of tap and drinking water for the people in Central and Eastern Thailand. The surveys were conducted in Bangkok city. Samples were collected from water treatment plants (WTPs), tap water, and drinking water. PFCs were detected in all tap water and drinking water samples. PFOS and PFOA concentrations in raw water of WTP were found 4.29 ng/L and 16.54 ng/L, respectively. The average PFOS and PFOA concentrations in tap water were detected 0.17 and 3.58 ng/L, respectively. The tap water results also showed that PFOS and PFOA concentrations were not similarly detected in all area in the city. PFOA were detected higher in the western area, while PFOS concentration was quite similar in all areas. Overall, it can be concluded that the current treatment processes were not completely remove PFCs. Nevertheless, PFCs in particulate phase were effectively removed by the primary sedimentation and rapid sand filtration. Elevated PFCs were found in the industrial zones (IZ2 and IZ5). To understand the distribution and fate of PFCs during industrial wastewater process, PFCs mass flows were studied. Higher PFCs in adsorbed phase were detected only in activated sludge and some influent samples. In IZ2, PFOA loading in the dissolved phase increased after activated sludge process by 5%. There was no degradation of PFOA inside the polishing pond. The highest loading to the treatment plant was PFOS with the loading of 2, 382 mg/d and 1, 529 mg/d in dissolved and adsorbed phase, respectively. Unlike PFCAs that showed no removal in the treatment process, PFOS were decreased during the treatment processes with 36% in the activated sludge process and 36% in the polishing pond. The predominant in this IZ5 was PFOS. The increasing of PFOS was also found in this treatment plant dissimilar to IZ2. PFOS was increasing by 45% in dissolved phase and 47% in adsorbed phase. All of PFCs in this industrial zone were detected higher in the effluent, indicated that PFCs’ precursors should be the major effects of this contamination.Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第14930号
工博第3157号
新制||工||1473(附属図書館)
27368
UT51-2009-M844
京都大学大学院工学研究科都市環境工学専攻
(主査)教授 田中 宏明, 教授 清水 芳久, 教授 藤井 滋穂
学位規則第4条第1項該当
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SENEVIRATHNA, SENEVIRATHNA THENNAKOON MUDIYANSELAGE LALANTHA DHARSHANA. "Development of Effective Removal Methods of PFCs (Perfluorinated Compounds) in Water by Adsorption and Coagulation." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/126798.
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Plakke, Anderson Bethany Joy. "Auditory working memory: contributions of lateral prefrontal cortex and acetylcholine in non-human primates." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/1060.
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Traditionally, working memory and its neural underpinnings have been studied in the visual domain. A rich and diverse amount of research has investigated the lateral prefrontal cortex (lPFC) as a primary area for visual working memory, while another line of research has found the neurotransmitter acetylcholine (ACh) to be involved. This dissertation used auditory cues and found similar patterns of activity for processing auditory working memory information within a task compared to visual working memory processes. The first two experimental chapters demonstrated that the cholinergic system is involved in auditory working memory in a comparable fashion to its role in visual working memory. In chapter 2, blocking ACh impaired performance on an auditory working memory task in a dose dependent manner. Chapter 3 investigated the specificity of the effect of blocking ACh by administering an ACh agonist (physostigmine) at the same time as an ACh antagonist (scopolamine). When both drugs were administered together performance on the delayed matching-to-sample task (DMTS) task improved compared to performance on scopolamine alone. These results support the hypothesis that ACh is involved in auditory working memory.
Chapter 4 investigated the neural correlates of auditory working memory in area 46 and found that this region of the lPFC contains neurons that are responsive to auditory working memory components in a very similar way to how it this region encodes information during visual working memory tasks. Neurons in the lPFC are responsive to visual or auditory cues, the delay portion of tasks, the wait time (i.e. decision making period), response, and reward times. This type of coding provides support for the theories that position the lPFC as a key player in recognition and working memory regardless of modality.
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Grote, Tobias [Verfasser]. "Digital control for interleaved boost power factor correction (PFC) rectifiers / Tobias Grote." Paderborn : Universitätsbibliothek, 2014. http://d-nb.info/105184813X/34.
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Lin, Cheng-Pin, and 林正斌. "Comparison Between Dual Phase Interleaved PFC Converter and ZCS PFC Converter." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/rnp27c.
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碩士崑山科技大學
電子工程研究所
96
In This thesis, we study and implement a 300W BCM (Boundary Current Mode) dual-phase interleave PFC (Power Factor correction) circuit and a 300W active PFC circuit with ZCS (Zero Current Switching)。 At first, we describe the operation and topology difference between these circuits, then design and implement both of these practical PFC circuits for performance comparison. Finally, the results of comparisons are presented. According to comparisons of switching waveforms, power factors and other relative experiment results, the BCM interleaved PFC and ZCS PFC are suitable for apply on cases under 300W and above 300W, respectively.
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Shen, Chuan-Hsing, and 沈俊興. "PFC: Packet Filter Cache." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/92813635078526655899.
Full textAbstract:
碩士元智大學
資訊工程學系
92
As communication technology advances, network capacity grows exponentially in recent years. The performance of network monitoring tools is getting more critical as they must process much lager number of packets in a unit of time than ever before. A common core component in any network monitoring tools is a packet filter which processes every packet header and passes those packets matching some filter rules to user spaces for further processing. Previous work on packet filters make an effort to investigate flexible and extensible filter abstractions but sacrifice performance, or focus on low-level, optimized filtering representations but sacrifice flexibility. In this paper, a packet filter architecture called Packet Filter Cache (PFC) is proposed to improve the performance of existing packet filters. The PFC architecture adds a filter rule cache before an existing packet filter. Instead of caching instruction set as in Warm cache, the filter rule cache stores the hash value of a filter rule as a hash table entry that can be searched in one memory access. By taking advantage of the hash lookup speed, PFC can boost filtering performance by using only small cache size. Moreover, PFC also caches unmatched packet flows to achieve high hit rate. Since PFC is only a cache mechanism added before a traditional packet filter, it does not need to re-engineer existing filter module and hence can be applied on most packet filters. Simulation shows PFC can improve the processing time about four times at cache hit rate of 70%.
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Yang, Chin-chi, and 楊清吉. "Realization and Comparison for a Single-stage Flyback PFC and a Single-stage SEPIC PFC." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/45293180514036399879.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
97
The rapid advancements in new materials and manufacturing technologies have facilitated the use of high-luminance LEDs for lighting applications, and they have efficacies (lm/W) above those of incandescent lamp, which are growing to fluorescent efficacy levels. Compared with fluorescent lamps, LED lamps have numerous advantages, such as up to 100,000 hours of operation life, a wide range of temperature operation for -20�aC to 120�aC, and their ability to work with low and safe voltages. In general lighting applications, a single-stage discontinuous current conduction mode (DCM) Flyback power factor correction (PFC) converter is commonly used to drive LED lamps for achieving a high power factor and regulating lamp current with a simple circuit configuration. However, DCM operation causes high peak current stresses and serious electromagnetic interference (EMI) problem. The thesis aims to study a coupled inductor SEPIC PFC converter topology for lighting LED driver. Continuous current conduction mode (CCM) operation on input current can be realized by using a commercial low-cost BCM PFC control IC. High efficiency and high power factor can be simultaneously achieved by the studied single-stage LED driver. The operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also implemented and tested to verify the feasibility. Finally, performance comparisons between the studied LED driver and the conventional single-stage DCM Flyback converter topology are also presented.
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McConkey, Clare Elizabeth. "Per- and Polyfluorinated Compounds in Blood and their Impact on Respiratory Problems in Young Children in Winnipeg, Manitoba." 2013. http://hdl.handle.net/1993/14919.
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Per- and polyfluorinated compounds (PFCs) are known to be toxic, bioaccumulative, and persistent. However, exposure routes and toxic effects in humans are still widely unknown. The concentrations of 17 PFCs were measured in newborn cord blood plasma and plasma from pre- and postnatal women from Winnipeg, Manitoba using online solid phase extraction coupled with liquid chromatography mass spectrometry. Median concentrations (with standard deviation) were 2.2 ng/mL (1.8 ng/mL) for perfluorooctanesulfonic acid (PFOS) and 0.89 ng/mL (0.75 ng/mL) for perfluorooctanoic acid (PFOA) in prenatal maternal plasma and 1.8 ng/mL (1.8 ng/mL) for PFOS and 0.55 ng/mL (0.46 ng/mL) for PFOA in postnatal maternal plasma. Multiple linear regression and principal component analysis were used to evaluate possible associations of maternal and infant characteristics with PFC concentrations. In general, concentrations of PFCs in plasma were associated with maternal characteristics, but not home characteristics, wheezing, or developmental effects.
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Lin, Jia-Yi, and 林佳儀. "PFC Rectifiers Based Bridgeless Boost Converter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/69808943006936706932.
Full textAbstract:
碩士國立交通大學
機械工程系所
101
This paper presents the AC to DC Power Factor Correction converter with boost topology, using average current mode in fixed 200kHz switching frequency, and using microcontroller TMS320F28035 to control the PWM duty ratio in continuous conduction mode to re-shape the input current waveform and in phase with the input voltage. Typically, the PFC stage is a bridge rectifier followed by a boost circuit. However, the current distortion and power losses in the diode bridge cannot be ignored, so the conventional PFC topology is replaced by bridgeless PFC topology. This paper using the full-load 300W with two boost circuits in parallel whitch operates alternately in positive and negative half cycle of AC input voltage, so the conduction loss and current shape distortion can be improved due to the reduction of the number of diodes compare to the conventional PFC topology. The experiment results show in full-load the power efficiency is 93.39% and the power factor reaches to 0.9994.
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Tsai, Chien-Li, and 蔡建利. "A Passive PFC Converter with ZCS." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/229sfd.
Full textAbstract:
碩士國立臺北科技大學
電機工程系研究所
96
The PFC (Power Factor Correction) circuit is widely used in various power supplies so as to reduce the corresponding harmonic distortion and to increase power factor. Up to now, the environment protection and the energy saving are getting more and more attractive in the world. Consequently, improvement in the overall efficiency of the power supply is indispensable, and hence enhancement of the efficiency of the PFC circuit is an important research topic. Consequently, a passive ZCS (Zero Current Switching) PFC circuit topology is presented herein, which is used on the characteristics of the saturable coupling inductor. As the PFC circuit works in the steady state, such an inductor is short-circuited, so as to make the loss in this inductor as minimum as possible. On the other hand, as the power switch of the PFC circuit is switched on, the saturable coupling inductor gets far away from the saturated condition and is represented as an inductor, so as to reduce the reverse recovery current of the boost diode and to absorb the portion of the energy created from this current. By doing so, the boost diode can be switched off under ZCS, and at the same time the switching loss of the main power switch can be reduced. Besides, before the main power switch is turned off and the boost diode is turned on, the ZCS circuit releases this stored energy to the output, so as to further upgrade the efficiency of the PFC circuit.
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Wang, Chien-Hung, and 王健鴻. "Digital Control for Cuk PFC Converter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/85361477657003231723.
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碩士國立交通大學
電機學院電機與控制學程
104
This thesis presents Cuk converter and its digital control method to achieve the power factor correction (PFC) function. Compared to the common dual- loop-control method, this thesis focuses on the new control mode to meet IEC61000-3-2 harmonic standard. This context is adopted from Texas Instruments C2000 series TMS320F28335 , of which DSP chip is to be controlled by the entire circuit. This DSP is categorized into TMS320F28X series, which has floating-point capabilities. Compared to the fixed-point DSP, it has not only more accuracy arithmetic function, but also has the advantages of low cost and low power consumption. Furthermore, it can hold greater data storage capacity and handle more accurate and faster AD converter, and so on. Digital Power Control is equipped easy and convenient applicability, providing better power management system, sophisticated power control solution, common design platform power control, cost decrease factor, and, most importantly, value-added intelligent integration. As the above-mentioned advantages are derived from programmable feature, so this is also a main factor to use DSP Chip to replace analog PWM IC.
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Chen, Ying-Chin, and 陳英欽. "Distribution and fate of perfluorinated compounds (PFCs) in wetland environment." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/39370317113748580487.
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博士國立臺灣大學
環境工程學研究所
100
Removals of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in pilot-scale field and sorption of PFOA and PFOS onto five types of soils were investigated in this study. Phytoextraction by four aquatic plants (Hygrophila pogonocalyx Hayata, Ipomoea aquatic Forssk, Ludwigia (x) taiwanensis and Eleocharis dulcis) and sorption onto soil were determined. Both PFOA and PFOS were fairly phytoextracted by four aquatic plants; the uptake capacity was found in the following order: Hygrophila pogonocalyx Hayata > Ipomoea aquatic Forssk ≈ Ludwigia (x) taiwanensis > Eleocharis dulcis. In the soil sorption experiment, equilibrium for PFOA and PFOS were achieved within 6 to 8 days; sorption capacity of 2–3 μg/g was observed at the end of the 15-d experiment. Experimental results and literature review suggest that phytoextraction and soil sorption were the most significant mechanisms for PFOA and PFOS disappearance in the pilot-scale constructed wetland, while contributions of biodegradation, photolysis, volatilization and hydrolysis were negligible. Effects of inorganic salts (CaCl2, NaCl, and Na2SO4) and humic acid in solution on the extent of sorption of PFOA and PFOS were also evaluated. The results indicated that all types of soils had a higher affinity for PFOS than for PFOA. The extent of sorption for PFOA and PFOS increased with fraction of organic carbon (foc) of soils. The partition coefficient (Kd) values of PFOA and PFOS increased with foc and ionic strengths of inorganic salts. On the contrary, the Kd values decreased with an increase in the concentrations of humic acid in the solution. The existence of organic matters is the parameter dominating the sorption behaviors of both PFOA and PFOS onto all types of soils studies. In addition, the presence of inorganic salts also affects PFC’s sorption behaviors.
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HIEU, PHAM PHU, and PHAM PHU HIEU. "Digital Control Strategy for Boost PFC Converter." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/27729671064086308862.
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碩士國立臺灣科技大學
電子工程系
103
Power factor correction (PFC) shapes the input current to minimize the reactive power drawing from the mains. The use of PFC circuits is widely discussed and considered for most off-line power supplies. For high power applications, boost PFC converter operated in continuous conduction mode is usually employed and controlled by analog ICs such as UC3854. However, when the converter operates at lower power range, discontinuous conduction mode will appear during parts of line period, causing input current distortion. Moreover, the input EMI filter causes the significant displacement between input voltage and input current when the converter operates at high-line light-load condition. With functions integrated inside analog ICs, they cannot be adapted to various mode of operation of circuit, resulting in poor power factor (PF) and high total harmonic distortion (THD). In order to implement more complex control scheme to improve PF and THD, the advantages of digital control are exploited. With flexibility, decreased number of components, less sensitivity with change of noise, low cost and increased performance, the digital controller is an interesting topic to research and employ for boost PFC converter. In this thesis, the digital controller what employs the Sample Correction, Duty Ratio Feed Forward and EMI filter capacitance current injection algorithms is proposed to solve above problems. A 400W Boost PFC prototype is implemented to verify the feasibility of the proposed control algorithms. The experimental results show the PF and THD improvements in both CCM and DCM operations.
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Liu, Jyun-Lin, and 劉俊麟. "A PFC Buck Rectifier with THD Improved." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/smhh9b.
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碩士國立臺北科技大學
電機工程系
106
A buck PFC rectifier with THD improved is developed herein. This converter operates in the discontinuous conduction mode (DCM) ,which makes the control easy. In addition, the diode has zero current turn-off such that there is no problem in reverse recovery current. Via output voltage sampling and voltage-follower control, a desired control force is created to drive the main power switch. By doing so, not only the output voltage is kept constant at a given value, but also the zero current region before and after the zero crossing point of the input current can be reduced. In this thesis, a voltage supperposition method is used such that the zero current region is reduced, thereby making the total harmonic decreased. Finally, the feasibility and effectiveness of the proposed method are verified by simulation and experiment, respectively.
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"Aplicação da Tecnologia Pfcp Integrada ao Capp em Ambiente de Ferramentaria." Tese, Programa de Pós Graduação em Engenharia de Produção, 1998. http://www.eps.ufsc.br/disserta98/knorst/index.html.
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Yang, Ya-Ting, and 楊雅婷. "Material Flow Analysis of PFCs for the Manufacturing Industry in Taiwan." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/12121288731490857784.
Full textAbstract:
碩士國立臺北大學
自然資源與環境管理研究所
96
In recent years, the influence of global warming has become much more serious than before. The topic of the reduction of greenhouse gases has been taken seriously through the world. In order to alleviate the global warming phenomenon effectively, the Kyoto Protocol which was adopted in Dec 1997 had made a consensus to lower overall emissions of six greenhouse gases- CO2, CH4, N2O, HFCs, PFCs and SF6. Comparing with the CO2 from traditional industries, the Per Fluorinated compounds (PFCs) from manufacturing industries have greater Global Warming Potential (GWP) and may exist in atmosphere for thousand of years. The amount of PFCs from manufacturing industries is not large right now; however, the weighted impact can not be ignored. The objective of this study was to investigate material flow analysis (MFA) of PFCs within the main semiconductor, TFT-LCD and solar photovoltaic industries in Taiwan, in the aspect of industrial ecology. It was intended to establish the framework for MFA of PFCs in our country and analyze input and output of PFCs for the manufacturing industries. The analysis can provide a full-scale examination and constructive suggestions for improvement. The results show the total PFCs emissions from the electronic manu- facturing industries contribute 1.6719 MMTCE in 2006 in Taiwan. The semiconductor industry contributes 74% of total emissions, the TFT-LCD industry contributes 25%, and the solar photovoltaic industry only contributes 1%. The study estimates the PFCs emissions from the electronic manufacturing industries will be 2.7494 MMTCE in 2010 in Taiwan. The semiconductor industry will contribute 65% of total PFCs emissions, the TFT-LCD industry will contribute 29%, and the solar photovoltaic industry will contribute 6%. Estimation of the PFCs emissions from the electronic manufacturing industries will be 5.7708 MMTCE in 2020 in Taiwan; the semiconductor industry will contribute 52% of the total PFCs emissions, the TFT-LCD industry will contribute 31%, and the solar photovoltaic industry will contribute 17%. The study also conducts a scenario simulation, and it takes into account the technology progress that affects the PFCs emissions in the future. In eight scenarios, the reductions of the PFCs emissions are 7.67%~29.67% in 2010, 20.52%~84.96% in 2020. The emissions of the PFCs from Semiconductor and TFT-LCD industries can not reached the desired amount in the international agreement in all scenarios in 2010. Even though there are no agreements of emissions for 2020, the emissions of the PFCs will reduce by 2.2745 MMTCE in all scenarios.
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Chen, Arvin, and 陳憲宏. "A Study PFCs Emission Reduction at PECVD tools Use Etching Gas." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/18092023145165856342.
Full textAbstract:
碩士明新科技大學
化學工程研究所
99
The optimized cleaning procedure is noticed by Semiconductor manufacturing in recent years. Semiconductor company A is successfully using C4F8 cleaning gas in Plasma Enhanced Chemical Vapor Deposition system (PECVD) . The cleaning gas, C4F8 , is also discussed and applied on CVD system in may articles. It is successfully demonstrated and resulted in reducing pollution to the environment. Semiconductor manufacture must comply the overall Carbon reduction of tax and provide a low cost solution to achieve Perfluoro-compounds (PFCs) against Carbon reduction. Thus, the C4F8 gas used in PECVD system is chose for developing high efficient cleaning gas in this research. The ASM Plasma-Enhanced Chemical Vapor Deposition system was chose for developing a new cleaning process on TEOS base of Silicon Dioxide and used high efficient cleaning gas, C4F8 . It was successfully developed a new cleaning process by using C4F8 and demonstrated its capability to reducing Perfluoro-compounds (PFCs) emission, meanwhile the consumption of cleaning gas reduction was also achieved. There were multiple abnormal situations happened, such like plasma damage to the component, contamination of the process chamber and white powder inside the exhaust line to limit the usage of cleaning gas. Thus, the readjustment of cleaning process was needed. As the result, it was not only successfully resolved the metal contamination issue when introducing new cleaning gas but also achieved the same preventive maintenance cycle with original C2F6. The productivity improvement and maintenance cost reduction were also demonstrated by reducing total cleaning gas and the interval of periodic in-situ chamber cleaning.
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Kuan-HsienChou and 周冠賢. "Design and Implementation of a Control IC forInterleaved BCM Boost PFCs." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/73170789178915553193.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
100
In this thesis, a novel interleaved BCM boost PFC control IC is designed and implemented. This contoller not only retains the advantage of low swtiching loss of BCM control but also increases the power rating of converter. The voltage mode master-slave interleaved control with turn-on instant phase-shift is adopted in the proposed controller. Conventionally, the interleaved BCM control scheme may occasionally operate in CCM due to pertubations. To solve this problem, the thesis proposes a novel phase-shifter to generate phase-shift signal. And the second zero current detector cooperated with the phase-shift signal is utilized to make the slave converter operate under BCM. In addition, this controller can always operate in normal condition even under the mismatch of two boost inductors. Finally, this chip is fabricated with TSMC 0.25 UM CMOS HIGH VOLTAGE MIXED SIGNAL BASED BCD 1P5M SALICIDE 2.5/5/60 V process.