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An Experimental Study on PEO Polymer Electrolyte Based All-Solid-State SupercapacitorYin, Yijing 25 June 2010 (has links)
Supercapacitors are one of the most important electrochemical energy storage and conversion devices, however low ionic conductivity of solid state polymer electrolytes and the poor accessibility of the ions to the active sites in the porous electrode will cause low performance for all-solid-state supercapacitors and will limit their application. The objective of the dissertation is to improve the performance of all-solid-state supercapactor by improving electrolyte conductivity and solving accessibility problem of the ions to the active sites. The low ionic conductivity (10-8 S/cm) of poly(ethylene oxide) (PEO) limits its application as an electrolyte. Since PEO is a semicrystal polymer and the ion conduction take place mainly in the amorphous regions of the PEO/Lithium salt complex, improvements in the percentage of amorphous phase in PEO or increasing the charge carrier concentration and mobility could increase the ionic conductivity of PEO electrolyte. Hot pressing along with the additions of different lithium salts, inorganic fillers and plasticizers were applied to improve the ionic conductivity of PEO polymer electrolytes. Four electrode methods were used to evaluate the conductivity of PEO based polymer electrolytes. Results show that adding certain lithium salts, inorganic fillers, and plasticizers could improve the ionic conductivity of PEO electrolytes up 10-4 S/cm. Further hot pressing treatment could improve the ionic conductivity of PEO electrolytes up to 10-3 S/cm. The conductivity improvement after hot pressing treatment is elucidated as that the spherulite crystal phase is convert into the fringed micelle crystal phase or the amorphous phase of PEO electrolytes. PEO electrolytes were added into active carbon as a binder and an ion conductor, so as to provide electrodes with not only ion conduction, but also the accessibility of ion to the active sites of electrodes. The NaI/I2 mediator was added to improve the conductivity of PEO electrolyte and provide pseudocapacitance for all-solid-state supercapacitors. Impedance, cyclic voltammetry, and gavalnostatic charge/discharge measurements were conducted to evaluate the electrochemical performance of PEO polymer electrolytes based all-solid-state supercapacitors. Results demonstrate that the conductivity of PEO electrolyte could be improved to 0.1 S/cm with a mediator concentration of 50wt%. A high conductivity in the PEO electrolyte with mediator is an indication of a high electron exchange rate between the mediator and mediator. The high electron exchange rates at mediator carbon interface and between mediator and mediator are essential in order to obtain a high response rate and high power. This automatically solves the accessibility problem. With the addition of NaI/I2 mediator, the specific capacitance increased more than 30 folds, specific power increased almost 20 folds, and specific energy increased around 10 folds. Further addition of filler to the electrodes along with the mediator could double the specific capacitor and specific power of the all-solid-state supercapacitor. The stability of the corresponded supercapacitor is good within 2000 cycles.
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Urinary excretion of histamine and methylhistamine after burnsJohansson, Joakim, Bäckryd, Emmanuel, Granerus, Göran, Sjöberg, Folke January 2012 (has links)
Background: The increased vascular permeability seen after burn contribute to morbidity and mortality as it interferes with organ function and the healing process. Large efforts have been made to explore underlying pathophysiological mechanisms that generate increased vascular permeability after burns. Many different substances have been proposed as mediators of which histamine, serotonin and oxygen radicals are claimed most important. However, no specific blocker has convincingly been shown to be clinically effective. Early work has claimed increased histamine plasma-concentrations in humans after burn and data from animal models pointed at histamine as an important mediator. Modern human clinical studies investigating the role of histamine as a mediator of the generalized post burn increase in vascular permeability are lacking. less thanbrgreater than less thanbrgreater thanMethod: We examined histamine turnover by measuring the urinary excretion of histamine and methyl histamine for 48 h after burns in 8 patients (mean total burn surface area 24%). less thanbrgreater than less thanbrgreater thanResults: Over time, in this time frame and compared to healthy controls we found a small increase in the excretion of histamine, but no increase of its metabolite methylhistamine. less thanbrgreater than less thanbrgreater thanConclusion: Our findings do not support that histamine is an important mediator of the increased systemic vascular permeability seen after burn. / <p>Funding Agencies|Research and Development Unit, Jamtland County Council, Sweden||</p>
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Alternative Redox Couples for Dye-Sensitized Solar CellsFeldt, Sandra January 2013 (has links)
Dye-sensitized solar cells (DSCs) convert sunlight to electricity at a low cost. In the DSC, a dye anchored to a mesoporous TiO2 semiconductor is responsible for capturing the sunlight. The resulting excited dye injects an electron into the conduction band of the TiO2 and is in turn regenerated by a redox mediator, normally iodide/triiodide, in a surrounding electrolyte. The success of the iodide/triiodide redox couple is mainly attributed to its slow interception of electrons at the TiO2 surface, which suppresses recombination losses in the DSC. One of the main limitations with the iodide/triiodide redox couple is, however, the large driving force needed for regeneration, which minimizes the open circuit voltage and thus the energy conversion efficiency. In this thesis, alternative redox couples to the iodide/triiodide redox couple have been investigated. These redox couples include the one-electron transition metal complexes, ferrocene and cobalt polypyridine complexes. The use of one-electron redox couples in the DSC has previously been shown to lead to poor photovoltaic performances, because of increased recombination. Cobalt redox couples were here found to give surprisingly high efficiencies in combination with the triphenylamine-based organic dye, D35. The success of the D35 dye, in combination with cobalt redox couples, was mainly attributed to the introduction of steric alkoxy chains on the dye, which supress recombination losses. By introducing steric substituents on the dye, rather than on the redox couple, mass transport limitations could in addition be avoided, which previously has been suggested to limit the performance of cobalt complexes in the DSC. The result of this study formed the basis for the world record efficiency of DSCs of 12.3 % using cobalt redox couples. Interfacial electron-transfer processes in cobalt-based DSCs were investigated to gain information of advantages and limitations using cobalt redox couples in the DSC. The redox potentials of cobalt redox couples are easily tuned by changing the coordination sphere of the complexes, and regeneration and recombination kinetics were systematically investigated by increasing the redox potential of the cobalt complexes. Our hope is that this thesis can be a guideline for future design of new redox systems in DSCs.
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The action research on the moot court of class¡GBased on law-related knowledge to elementary students and its relevant influences.Weng, Jui-mei 26 July 2005 (has links)
Abstract
This report describes an action research project that was designed to determine the effect of using the moot court of class and relative teaching activities in the elementary school, especially on students¡¦ law-related knowledge and other relevant influences.
By founding the moot court of class, the purpose of the research was to give students law-related knowledge and establish classroom rules through the arbitration and public justice of the third-party advisor. In the process of participating public affairs, students learned to know the difference between right and wrong, developed the moral qualities full of respect and forgiveness, and then promoted students¡¦ ability on critical thinking and self-reflection at the same time. The model increased the function of self-governing activities in the class, reduced the amount of time and frequencies for the teacher to deal with students¡¦ arguments, and finally achieved the aim to help students follow rules, promote students¡¦ learning results and the teacher¡¦s teaching effect. Through the strategies used to help students correct their own interpersonal interaction styles, students could be accepted by the whole group and became one important group member. The model fulfilled the three education goals¡Xteaching, integrating into lives, advising and correction.
According to data analysis and observation, the major findings of this research were as follows.
1. The events and causes of students¡¦ arguments did not change a lot with time and places.
2. Students liked to participate activities in the moot court of class. The atmosphere was serious but warm.
3. Procrastination changed the way how students faced conflicts and reduced the interruption on the teacher¡¦s teaching process.
4. The function of the moot court of class was to solve conflicts, and then counseling strategies were use to lead the thought and improve behavior.
5. The model had positive effect on students¡¦ self-reflection and critical thinking.
6. Under the suitable model, classroom rules didn¡¦t have to be made right after the school year began.
7. The third-party advisor was helpful to complete communication, and made the arbitration to good effect.
8. The arbitration in a group had positive influence on students¡¦ self- discipline.
According to the research results, the suggestions for educators were as follows.
1. Give students opportunities of expressing themselves in writings to balance the function of oral communication.
2. Use Homeroom Teacher¡¦s Time well to put law education into practice in daily life.
3. Make the disciplinary policy in cooperation between the teacher and students. Notice the power of the teacher to avoid indulgence.
4. Keep teaching records, and adjust according to students¡¦ needs.
5. Make reference to law-related websites to combine life with learning.
6. Use counseling strategies properly to help students perceive knowledge and carry it out in daily life.
7. Communicate the ideas of class management with students¡¦ parents to avoid any misunderstandings.
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A study of the Competence-based Model to Choose Labor Conflict Mediators Based on the Application of Analytic Network ProcessChuang, Ping-Fen 07 September 2008 (has links)
Labor conflict mediators play a very important role during the process of labor dispute resolution; their competence will help enhance the quality of labor dispute mediation and improve the relationship between labor and management. The main purpose of this research is to probe into the criteria that labor conflict mediators should possess. Based on the Competence Theory, this research collects opinions from experts and scholars and utilizes Fuzzy Delphi Method and Analytic Network Process respectively to construct a competence-based model to select labor conflict mediators.
Results are achieved as follows:
1. To firmly establish critical competence items and definition of labor conflict mediators, including practical experience, problem resolution, professional expertise, fairness and objectivity, integrity, thinking and judgment, and investigation ability, in order to set up the hierarchical structure of competency indices.
2. In consideration of the dependency relation among principles of competency, this research utilizes Analytic Network Process to systematize decomposition and quantify judgment, in order to firmly establish the weight of competency indices, as well as to construct a competence-based model with an evaluation standard of weight to select labor conflict mediators.
3. Through the empirical study, the competence-based model to select labor conflict mediators which is constructed in this research can effectively discriminate outstanding labor conflict mediators.
4. The competence-based model developed in this research to choose labor conflict mediators utilizes the following procedures: (1) collate the competence indices; (2) To utilize Fuzzy Delphi Method to identify critical items of competence; (3) To utilize Analytic Network Process to firmly establish the weight of competence items; (4) To develop the competence-based model; (5) To examine the effectiveness of competence-based model.
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Eating Disorders : Steps Towards an Increased UnderstandingWelch, Elisabeth January 2014 (has links)
Eating disorders and disordered eating attitudes and behaviors are characterized by an over-evaluation of weight and shape, under or over-controlled eating, as well as engagement in compensatory behaviors. The disorders are associated with psychological suffering, acute and long-term health impairments, a high rate of suicide attempts as well as an increased risk of mortality. Knowledge regarding the etiology of eating disorders is limited and based on current models it is not possible to adequately predict either who will get an eating disorder or who will recover. This lack of understanding has hindered the development of effective prevention and treatment interventions. The aim of the present thesis was to contribute towards an increased understanding of eating disorders and disordered eating attitudes and behavior through the collection of norms and psychometric data, investigation of risk factors and their roles, and focusing on the understudied group of males with eating disorders. Five studies were included. Specifically, Study I focused on collecting general population and clinical norms on the well-established Eating Disorder Examination Questionnaire (EDE-Q) and the Clinical Impairment Assessment Questionnaire (CIA). Study II both collected general population norms on, and investigated psychometric properties of, the Body Shape Questionnaire (BSQ-8C), an instrument intended to assess body dissatisfaction. Study III focused on the role of perfectionism (an established risk factor for eating disorders) as a possible mediator or moderator between body dissatisfaction and disordered eating behavior and attitudes. Finally, in Study IV and V attention was placed on males. In Study IV the specific aim was to compare the clinical characteristics between young males and females with eating disorders while in study V the specific aim was to explore variables associated with disordered eating among young males based on a compilation of factors known to play a role among females as well as factors thought to be uniquely associated with males, such as sexual orientation and drive for muscularity. A greater understanding of eating disorders will help reduce the stigma that is associated with eating disorders, easing the way for affected individuals to seek help and ultimately improve the development of effective prevention and intervention.
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Hur upplevs det att arbeta som kontakttolk respektive som kulturtolkHalili, Qendresa January 2014 (has links)
Tidigare forskning kring tolkarbetet visar att tolkyrket har utvecklats och spelar en viktig roll i samhället. Tolkarbetet anses vara en stressframkallande aktivitet. En tolk genomför en kommunikation mellan två partner som inte tillämpar samma språk. Kulturtolk förklarar informationen mer djupgående medan kontakttolken tolkar endast det som sägs utan vidare förklaring. Syftet med studien var att undersöka hur kontakttolkar och kulturtolkar upplever sina arbeten. Fyra kvinnor och fyra män med olika modersmål som arbetade som tolk i Mellansverige intervjuades. Resultatet visade att tolkyrket upplevdes ganska trivsamt trots att det kunde innebära stress, svårigheter och känslomässiga situationer. Stress upplevdes i samband med tidsbrist. Känslomässiga situationer uppstod med förmedling av jobbiga besked. Trivsamhet upplevdes med arbetsmiljö. Individer som var analfabeter samt med skilda dialekter, försvårade tolkningen. Kontakttolkar upplevde vissa begränsningar i sina arbeten, medan kulturtolkar ansåg vara mer flexibla. Med tanke på den ständiga förändringen i omvärlden behövs en kontinuerlig utveckling av tolkarbetet.
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Die Unabhängigkeit und Unparteilichkeit des MediatorsTochtermann, Peter January 2008 (has links)
Zugl.: Heidelberg, Univ., Diss., 2008
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Charakterisierung der molekularen Grundlagen des protektiven Effektes von Shear Stress auf die Apoptose von Endothelzellen /Hermann, Corinna. January 2000 (has links)
Universiẗat, Diss., 1999--Frankfurt (Main).
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Die Bedeutung des Renin-Angiotensin-Systems und der Mediatoren Histamin und Tryptase bei Bienen- und Wespengift-Allergie vor und nach StichprovokationLiebetrau, Annette. Unknown Date (has links)
Techn. Universiẗat, Diss., 2005--München.
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