Converter devided into linear converter and switching-mode cinverter. push pull has large hystersis loop,so that it supples large power compared with forward topology.it has another adventage ,is easy to drive than half-bridge or full-bridge .the main purpose of the thesis is to study and design push pull converter . First, it is detail to analysis push pull converter's theorem.afterward the push pull converter is described including the component and circuit design .finally push pull converter is implemented and demonstrated

Duisburg, University, Diss., 2002.

Résumé : Au cours des dernières décennies, la conception de nouveaux polymères «push-pull» a été le sujet d'intenses recherches pour les cellules photovoltaïques. Cette thèse de doctorat comprend deux sujets principaux de recherche, l'une est la synthèse et la caractérisation de polymères organométalliques contenant l’unité trans-bis(éthynyl)bis(tributylphosphine)platine(II) comme l’un de deux blocs de construction et des dérivés quinoniques et anthraquinoniques agissant respectivement comme donneur et accepteur de densité électronique, et ainsi que des composés modèles correspondants pour fins de comparaison. L’autre sujet traite des polymères contenant l’unité zinc(II)porphyrine (donneur) et les mêmes dérivés quinoniques et anthraquinoniques. Habituellement les polymères «push-pull» conjugués sont tout d'abord étudiés car ils peuvent montrer de nouvelles bandes d’absorption dites bandes de transfert de charge vers le rouge du spectre solaire, démontrant ainsi l’existence de communication électronique à travers la chaine du polymère, mais aussi permettant de collecter plus de photons par le matériau. Ce travail est divisé en quatre chapitres. / Abstract : In recent decades, the design of new « push-pull » polymers has been the subject of intense research for photovoltaic cell applications. This thesis deals with two main subjects, one is the synthesis and characterization of organometallic trans-bis(ethynyl)bis(tributylphosphine)platinum(II), ([Pt]) and quinone or anthraquinone derivatives-based polymers. Some model compounds have been produced as well for comparison purposes. Another issue is the synthesis and characterization of polymers built upon zinc(II)porphyrin units and the same quinone and anthraquinone derivatives respectively acting as donor and acceptor of electronic density. Such «push-pull» polymers are used to be investigated because of their so-called charge transfer absorption bands in the red part of the solar spectrum. This phenomenon is due to the electronic communication over the whole chain. This new band allows the material to collect more photons. The whole work is divided into four chapters.

A series of push-pull systems with different electron donors and electron acceptors were investigated. The carbon-carbon double bond rotational barriers for twelve push-pull ethylene derivatives, NH2CH=CHX, NH2H=CHX and -OCH=CHX (acceptors, X = BH2, CN, NO2, and +CH2) were studied by ab initio calculations. The rotational barrier was chosen as a probe for push-pull effects, as push-pull effects would remove electrons from the central double bond. Complete geometry optimizations and calculations of vibrational frequencies were performed for all minima and transition state structures of the twelve systems. The Synchronous Transit-Guided Quasi-Newton (STQN) method was used to search for the transition state structures. The calculations were carried out at B3LYP/6-31++G(d,p) and MP2/6-311++G(d,p) levels of theory. Electron density maps were used to analyze the electron density distribution. The Merz-Singh-Kollman scheme was chosen to calculate electrostatic potential derived charges on atoms. Calculations at the MP2 level suggest that the strongest push-pull effects result from +CH2 with barriers (to conversion to the transorms) of 10.6, 13.2, and 7.3 kcal/mol for NH2CH=CHCH2+, NH2H=CHCH2+, and -OCH=CHCH2+, respectively. These barriers are about 6, 5, and 9 times smaller than that of ethylene at the same level of theory, respectively. Among the other electron acceptors studied, BH2 was stronger than the cyano and nitro substituents but weaker than CH2+. Solvent effects were examined for the NH2CH=CHX system, X = BH2, CN, NO2, and +CH2 with water and dichloromethane as solvents. Calculations were performed at the B3LYP/6-31++G(d,p) level of theory using three different approaches, the Conductor-like Screening Model (COSMO), the Polarizable Continuum Model (PCM) and the Super-Molecular Approach (SMA). When the solvent is water, SMA calculations retained the barrier-height order of gas phase calculations, while COSMO and PCM reversed the order of BH2 and NO2. Results from this research confirm that both solvents lowered the rotational barriers in all cases. The more polar solvent decreases the rotational barrier more than the less polar solvent due to the existing of a dipolar or charge separated transition states of the push-pull systems.

Uppsatsen syftade till att 1) öka förståelsen varför kvinnor lämnat rollen som chef och 2) om det fanns skillnader mot män som lämnat rollen som chef. Resultaten visade att kvinnor i lämnade pga. "push"-orsaker, dvs. att man ej var nöjd, medan männen lämnade pga. "pull"-orsaker, positivt motiverande faktorer. Studien visade också att de kvinnor som stannade kvar i rollen som chef gjorde det pga. "pull"-orsaker. Arbetet baserades på en intervjustudie av 16 personer under våren 2010. Slutsatsen var att kvinnor oftare trycktes ut ur chefsrollen genom missnöje, medan männen drogs ut ur chefsrollen genom att lockas vidare. / The thesis was aimed to 1) increase the understanding of why women left the role as a manager and 2) if there was any differences between them and the men who left the role as a manager. The results showed that women left because of push-factors, that they weren’t satisfied, whereas men left because of pull-factors, positively motivating factors. The study also showed that women who stayed in the role as a manger did so because of pull-factors. The study was based on interviews of 16 persons during spring 2010. The conclusion was that women more often were pushed out of the manager role because of discontent, whereas men were pulled out because of attraction to something else.

The problems associated with the contamination of groundwater environments by non-aqueous phase liquids (NAPLs) such as chlorinated solvents, gasoline and manufacturing gas plant (MGP) residuals, including their distribution and persistence, are well accepted. The treatment of groundwater by in situ chemical oxidation (ISCO) relies on the oxidation potential of chemical reagents to destroy harmful organic compounds. The interaction of these oxidants with target and non-target compounds in the subsurface will help determine effectiveness and efficiency of an ISCO treatment system. Push-pull tests (PPTs) have the utility to estimate key properties in situ and allow for sampling a larger volume of aquifer to yield more representative estimates as compared to conventional bench-scale tests. The scale and cost-effectiveness of a PPT make it an ideal tool to collect valuable information on subsurface system behaviour so that uncertainties can be minimized. The use of PPTs to provide insight into treatment expectations or to support the design of an ISCO system requires a suitable interpretation tool. A multi-species numerical model (‘PPT-ISCO’) in a radial coordinate system was developed to simulate a PPT with the injection of a conservative tracer and oxidant (persulfate or permanganate) into the saturated zone of a porous medium environment. The pore space may contain variable amounts of immobile, multicomponent, residual NAPL. The aquifer material contains a natural organic matter (NOM) fraction and/or other oxidizable aquifer material (OAM) species. The model is capable of simulating mass transport for an arbitrary number of conservative and reactive tracers and NAPL constituents subjected to chemical reactions. The ability of PPTs to capture the in situ natural oxidant interaction (NOI) was tested with PPTISCO. Breakthrough curve (BTC) data collected from permanganate and persulfate PPTs conducted in the field were compared to simulated BTCs by assigning the same field operational parameters to the model and applying NOI kinetic information obtained from batch tests. These tests confirmed the usability of the model and PPTs to obtain the NOI kinetics from PPT BTCs. The sensitivity of PPT BTCs to variations in the field operating and NOI parameters were investigated. The results of varying the field operating parameters indicated that the oxidant BTCs could be scaled to match varying injection and extraction flow rates. Variations in NOI parameters revealed that the permanganate BTC is primarily controlled by the permanganate fast reaction rate coefficient and the quantity of OAM present in the aquifer. The spatial profiles of OAM across the test zone revealed that the majority of the OAM consumption is from the fast fraction and occurs in the vicinity of the well where the permanganate concentration is greatest. An estimate of the permanganate fast reaction rate coefficient can be obtained from a permanganate PPT BTC by employing the model to simulate the PPT with the operational parameters (used in the field) and literature estimates of the remaining NOI parameters. Calibration between the simulated and observed BTCs can be undertaken to adjust the permanganate fast reaction rate coefficient to fit the permanganate PPT BTC. Persulfate NOI sensitivity investigations revealed that persulfate PPT BTCs can be characterized by a concentration plateau at early times as a result of the increased ionic strength in the area around the injection well. The ionic strength is primarily controlled by the injected persulfate concentration, and as persulfate degrades into sulphate and acid, the ionic strength is enhanced. Graphical analysis of the BTC revealed that an underestimated value of the persulfate degradation rate coefficient can be obtained from the PPT BTC. A more representative estimate of the persulfate degradation rate coefficient can be achieved after fitting the field BTC to the simulated results, applying the underestimated value as a starting point. PPTs investigating ISCO treatability have the ability to provide insight into the effect of the NOI on the oxidation of target compounds, site-specific oxidant dosage requirements and NAPL treatment expectations. NAPL component BTCs from treatability PPTs are primarily controlled by the mass in the fast region, and the fast region mass transfer rate coefficient. Oxidation estimates extracted from NAPL component BTCs were shown to accurately approximate the mass of each NAPL component oxidized when compared to model calculations. The mass of NAPL oxidized for each of the components yields a site-specific oxidant dosage. This estimate exceeds what is prescribed by the stoichiometry between permanganate and the contaminant of concern due to the effect of the NOI. The utility of PPTs to study and quantify the interaction between injected oxidants and the aquifer material has been demonstrated with PPT-ISCO. In addition, PPT-ISCO has revealed that treatability PPTs can be tailored to investigate the dosage requirements and treatment expectations of residual NAPLs. Results from this effort will be used to support ongoing field research exploring the use of PPTs to assist in understanding the competing subsurface processes affecting ISCO applications.

Since 1960, the aboriginal of Taiwan have gradually moved to urban areas, living with a kind of gathering or spreading style. So far, urban aboriginals become the majority among other kinds of aboriginals. Facing illegally gathered clusters of buildings over national lands, villages and riversides occupied by urban aboriginals, researcher have been trying to find out why those aboriginals moved into urban areas? How did those urban aboriginals select a suitable settlement for them? And what about current standard of living and conditions they could manage and reach? In order to find out the migration behaviour of urban aboriginals in this research, researcher use qualitative research such as interview, interpretive methods. From the various results of this research, it can be seen that some aboriginals of Amis are living in a closed environment located at San-Ying tribe in Taipei County. They are not only facing shortage goods, unstable working condition, but also having little educational training. They moved from original area to urban areas caused by economic reason. Different workplace caused urban aboriginal live, when they can¡¦t fine a job, they¡¦ll try to find somewhere to live. San-Ying tribe was chosen as the destination for new settlement because of friends¡¦ notice and a consideration of the position. For them, this new settlement has already been the second original area and almost of their colleagues and friends do make their living in the urban areas as it is easy to get a job there. What San-Ying tribe residents want now is to have a stable income and a home for them to survive in the society. Researcher suppose these problems lying on cooperation and collaborations between government and civil organizations to settlement solutions, employment solutions and educational solutions.

The problems associated with the contamination of groundwater environments by non-aqueous phase liquids (NAPLs) such as chlorinated solvents, gasoline and manufacturing gas plant (MGP) residuals, including their distribution and persistence, are well accepted. The treatment of groundwater by in situ chemical oxidation (ISCO) relies on the oxidation potential of chemical reagents to destroy harmful organic compounds. The interaction of these oxidants with target and non-target compounds in the subsurface will help determine effectiveness and efficiency of an ISCO treatment system. Push-pull tests (PPTs) have the utility to estimate key properties in situ and allow for sampling a larger volume of aquifer to yield more representative estimates as compared to conventional bench-scale tests. The scale and cost-effectiveness of a PPT make it an ideal tool to collect valuable information on subsurface system behaviour so that uncertainties can be minimized. The use of PPTs to provide insight into treatment expectations or to support the design of an ISCO system requires a suitable interpretation tool. A multi-species numerical model (‘PPT-ISCO’) in a radial coordinate system was developed to simulate a PPT with the injection of a conservative tracer and oxidant (persulfate or permanganate) into the saturated zone of a porous medium environment. The pore space may contain variable amounts of immobile, multicomponent, residual NAPL. The aquifer material contains a natural organic matter (NOM) fraction and/or other oxidizable aquifer material (OAM) species. The model is capable of simulating mass transport for an arbitrary number of conservative and reactive tracers and NAPL constituents subjected to chemical reactions. The ability of PPTs to capture the in situ natural oxidant interaction (NOI) was tested with PPTISCO. Breakthrough curve (BTC) data collected from permanganate and persulfate PPTs conducted in the field were compared to simulated BTCs by assigning the same field operational parameters to the model and applying NOI kinetic information obtained from batch tests. These tests confirmed the usability of the model and PPTs to obtain the NOI kinetics from PPT BTCs. The sensitivity of PPT BTCs to variations in the field operating and NOI parameters were investigated. The results of varying the field operating parameters indicated that the oxidant BTCs could be scaled to match varying injection and extraction flow rates. Variations in NOI parameters revealed that the permanganate BTC is primarily controlled by the permanganate fast reaction rate coefficient and the quantity of OAM present in the aquifer. The spatial profiles of OAM across the test zone revealed that the majority of the OAM consumption is from the fast fraction and occurs in the vicinity of the well where the permanganate concentration is greatest. An estimate of the permanganate fast reaction rate coefficient can be obtained from a permanganate PPT BTC by employing the model to simulate the PPT with the operational parameters (used in the field) and literature estimates of the remaining NOI parameters. Calibration between the simulated and observed BTCs can be undertaken to adjust the permanganate fast reaction rate coefficient to fit the permanganate PPT BTC. Persulfate NOI sensitivity investigations revealed that persulfate PPT BTCs can be characterized by a concentration plateau at early times as a result of the increased ionic strength in the area around the injection well. The ionic strength is primarily controlled by the injected persulfate concentration, and as persulfate degrades into sulphate and acid, the ionic strength is enhanced. Graphical analysis of the BTC revealed that an underestimated value of the persulfate degradation rate coefficient can be obtained from the PPT BTC. A more representative estimate of the persulfate degradation rate coefficient can be achieved after fitting the field BTC to the simulated results, applying the underestimated value as a starting point. PPTs investigating ISCO treatability have the ability to provide insight into the effect of the NOI on the oxidation of target compounds, site-specific oxidant dosage requirements and NAPL treatment expectations. NAPL component BTCs from treatability PPTs are primarily controlled by the mass in the fast region, and the fast region mass transfer rate coefficient. Oxidation estimates extracted from NAPL component BTCs were shown to accurately approximate the mass of each NAPL component oxidized when compared to model calculations. The mass of NAPL oxidized for each of the components yields a site-specific oxidant dosage. This estimate exceeds what is prescribed by the stoichiometry between permanganate and the contaminant of concern due to the effect of the NOI. The utility of PPTs to study and quantify the interaction between injected oxidants and the aquifer material has been demonstrated with PPT-ISCO. In addition, PPT-ISCO has revealed that treatability PPTs can be tailored to investigate the dosage requirements and treatment expectations of residual NAPLs. Results from this effort will be used to support ongoing field research exploring the use of PPTs to assist in understanding the competing subsurface processes affecting ISCO applications.

Les travaux présentés dans cette thèse ont pour objectif de contribuer au développement des cellules photovoltaïques hybrides employant un colorant organique pour sensibiliser un semi-conducteur de type p (NiO). Ces travaux de recherche ont porté sur la synthèse, l’étude théorique par des calculs DFT, les caractérisations physico-chimiques (absorption, émission, électrochimie et spectro-électrochimie) et les mesures photovoltaïques de sensibilisateurs innovants. Des modulations de structures sur la base du motif dicétopyrrolopyrrole (DPP) ont permis d’étudier l’influence d’une entité électrodonneuse ainsi que le rôle crucial de différents groupes électroaccepteurs sur la durée de vie de l’état à charges séparées (NiO+/colorant-) et sur les performances photovoltaïques. L’intensification et l’élargissement des bandes d’absorption de nouveaux colorants fondés sur cette même famille de sensibilisateur (DPP) ont accru considérablement la densité de courant. L’étude de nouveaux matériaux organiques de type donneur-accepteur et l’application d’une stratégie employant deux groupes accepteurs successifs de forces croissantes ont été réalisées. Cette partie a mis en lumière la nécessité de développer de nouveaux groupes électrodonneurs et fonctions d’ancrage mieux adaptées aux p-DSSC. Cette problématique a été abordée par la conception de colorants de type pérylène-monoimide dont la structure varie uniquement par la nature de la fonction d’ancrage. Ces colorants ont été testés dans des cellules sur des cathodes poreuses de NiO et de CuGaO2 et ont pu montrer que la fonction hydroxyquinoline conduit à des performances photovoltaïques supérieures à la fonction acide carboxylique. / This thesis aims at contributing to the development of dye sensitized solar cells (DSSC) that are based on an organic dye and a p-type semi-conductor as photocathode such as NiO. In this context, these studies focus on the synthesis, the theoretical study by DFT calculations, the physicochemical characterizations (absorption and emission spectra, electrochemistry and spectroelectrochemistry) and photovoltaic characterizations of these innovative sensitizers. Structure modulations on a diketopyrrolopyrrole dye (DPP) investigate the influence of an electron-donating group and the crucial role of different electron-withdrawing groups on the lifetime of the charge separation state (NiO+/dye-) and on the photovoltaic performances. Enhancement and broadening of the absorption bands with new sensitizers have enabled to considerably increase the photocurrent density and to reach among the highest values reported in the literature with the best dyes. Synthesis of new organic push-pull dyes and the application of a strategy using two successive electron-withdrawing groups of growing strengths have been realized. This part highlights the necessity to develop new electron-donating and anchoring groups for p-type dye sensitized solar cells. This point issue was investigated in the final chapter of this thesis by the design of new perylene monoimide sensitizers, whose structures only differ by the nature of the anchoring group (CO2H, acac, PO3H2, hydroxyquinoline…). These dyes were investigated in DSSCs with porous cathode made of NiO or CuGaO2. It was shown that the binding group hydroxyquinoline gives higher photovoltaic performances than the classical carboxylic acid group.

The topic of the master thesis is an analysis of the attitude of future graduates towards self-employment. The aim of the thesis is to find out, within the push-pull theory, which factors currently influence graduates in decision-making whether to be employed or to start their own business and whether their attitude has changed due to the situation in society associated with the COVID-19 pandemic. The research will be conducted by a questionnaire survey. The result of the thesis will be a comparison of motives for decision-making between employment and entrepreneurship before and during the pandemic crisis. Based on the research results, solutions for increasing motivation of future graduates to become entrepreneurs and suggestions for improving strategy of business support organizations to support entrepreneurship among graduates according to their needs will be proposed