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Characterization of poly-b-alanine (nylon 3)Odozi, Thomas O. 01 May 1979 (has links)
A low molecular weight po1y-S-a1anine (350 row) was prepared by thermal po1ycondensation of S-a1anine ethyl ester. In thermal analysis, six transitions occurred in the initial polymer in approximate order of increasing temperature: glass transition temperature (Tg), crysta1- crystal transition, cold crystallization, melt crystallization, crystalline disorientation, and melting. Isothermal annealing of this polymer at 200 0 followed by quenching provided structures which exhibited multiple melting peaks in thermal analysis. In this work reasons are proposed for the dual endotherm. By prolonged annealing only, before analysis, part of the recrystallization exotherm can be observed in the differential scanning calorimetry (DSC) scan. DSC thermo grams obtained at varying heating rates on samples showing po1y-S-a1anine endotherms supported the assignment of superheating as the cause of the shift to higher peak temperatures with increasing heating rate. To further support the structural assignment, the infrared absorption showed typical polyamide bands, and the nuclear magnetic resonance spectrum gave two methylene peaks of equal intensity.
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Polyalanine domain expansion confers nuclear export activity on proteins.January 2013 (has links)
研究發現有九種人類疾病與丙胺酸(alanine)鏈的擴展相關。其中八種聚丙胺酸(polyA)疾病的蛋白是轉錄因子(transcription factor),並在發育和分化過程中發揮重要作用。轉錄因子含有細胞核定位訊號(nuclear localization signal; NLS),可使其定位到細胞核並與DNA序列結合調控轉錄。因此,轉錄因子的核定位是至關重要的。研究指帶有polyA鏈的疾病蛋白主要定位在細胞質而不在細胞核裡。因此,我假設polyA疾病蛋白中的polyA鏈擴展區域帯有核輸出訊號(nuclear export signal; NES),使polyA疾病蛋白從細胞核輸出到細胞質。所以,細胞質中的疾病蛋白質不能啟動轉錄。為了驗證這一假說,我使用核輸出報告蛋白來代表定位於細胞核內的polyA疾病蛋白。我的實驗結果顯示擴展polyA鏈使得核輸出報告蛋白定位於細胞質。這與polyA疾病蛋白的研究結果一致。再者,我運用光漂白期螢光消退(Fluorescence Loss in Photobleaching; FLIP)核輸出實驗和光激發螢光蛋白(Photoactivatable-GFP; PA-GFP)核輸出實驗來進一步証明在活細胞中存在擴展polyA鏈核輸出現象。我運用谷胱甘肽巯基轉移酶(glutathione-S-transferase; GST)沉澱法証實真核翻譯延長因子1A(eukaryotic translation elongation 1 alpha; EEF1A)是一個擴展polyA鏈的互作因子. 最後,我用小片段干擾RNA(siRNA)誘發的基因沈默確定了EEF1A與擴展polyA鏈的核輸出相關。綜上所述,我的研究証實了擴展polyA鏈是一類新的NES並且其核輸出是由EEF1A參與的未証實的輸出通路所介導的。通過識別其他能調節polyA疾病蛋白核輸出的互作因子,我們將會進一步了解polyA疾病的發病機理。 / The expansion of alanine tracts in disease proteins is found to be associated with nine human diseases. Eight out of nine polyalanine (polyA) disease proteins are transcription factors which play important roles during development and differentiation. Transcription factors contain nuclear localization signals (NLS) that direct them to the nucleus and bind to specific regulatory DNA sequences to regulate transcription. Therefore, nuclear localization is essential for transcription factors to function. Intriguingly, it has been reported that the expanded polyA disease proteins primarily localize in the cytoplasm. Therefore I hypothesize that the expansion of polyA domain in the disease proteins generates a nuclear export signal (NES) which directs nuclear export of polyA disease proteins. As a result, cytoplasmic expanded polyA disease proteins cannot initiate transcription. To test this hypothesis, I first used a nuclear export reporter protein to represent the polyA disease proteins that localized in the nucleus. The insertion of expanded polyA tract conferred cytoplasmic localization of the nuclear export reporter protein as previously reported in polyA disease proteins. I further made use of Fluorescence Loss in Photobleaching (FLIP) Nuclear Export Assay and Photoactivatable-GFP (PA-GFP) Nuclear Export Assay to illustrate the nuclear export of expanded polyA protein in living cells. Finally, by means of glutathione-S-transferase (GST) pull-down assay followed by mass spectrometry, I identified eukaryotic translation elongation factor 1 alpha (EEF1A) as a novel interacting partner of expanded polyA tract and that EEF1A is involved in expanded polyA protein’s nuclear export by means of a siRNA-mediated gene silencing experiment. Taken together, my study identified expanded polyA tract as a novel class of NES and its nuclear export is mediated by an unidentified export pathway involving EEF1A. Through the identification of other factors that modulate nuclear export of polyA disease proteins, we will have a better understanding of the pathogenesis of polyA diseases. / Detailed summary in vernacular field only. / Ng, Ka Lam. / "November 2012." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 108-112). / Abstracts also in Chinese. / ABSTRACT --- p.i / ABSTRACT (Chinese version) --- p.iii / ACKNOWLEDGEMENTS --- p.iv / LIST OF ABBREVIATIONS --- p.v / LIST OF TABLES --- p.ix / LIST OF FIGURES --- p.xi / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Polyalanine diseases --- p.1 / Chapter 1.1.1 --- Overview of polyalanine diseases --- p.1 / Chapter 1.1.2 --- Polyalanine tract expansion in transcription factors --- p.1 / Chapter 1.2 --- Nuclear export in eukaryotic cells --- p.5 / Chapter 1.2.1 --- Overview of nucleocytoplasmic transport --- p.5 / Chapter 1.2.2 --- Classical exportins and nuclear export signal --- p.6 / Chapter 1.2.3 --- Non-classical exportins and nuclear export signal --- p.6 / Chapter 1.2.4 --- Role of eukaryotic translation elongation factor alpha 1 in protein nuclear export --- p.7 / Chapter 1.3 --- Aim of study --- p.8 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Molecular cloning of plasmid constructs --- p.9 / Chapter 2.1.1 --- Annealing of double-stranded oligonucleotides --- p.13 / Chapter 2.1.2 --- Phosphorylation at 5' position of double-stranded oligonucleotides --- p.13 / Chapter 2.1.3 --- Polymerase chain reaction --- p.14 / Chapter 2.1.4 --- Restriction enzyme digestion of cloning vector and insert sequence --- p.15 / Chapter 2.1.5 --- Removal of 5' phosphate groups from cloning vector --- p.15 / Chapter 2.1.6 --- DNA gel electrophoresis --- p.16 / Chapter 2.1.7 --- Gel extraction and purification of DNA --- p.16 / Chapter 2.1.8 --- DNA ligation --- p.16 / Chapter 2.1.9 --- Bacterial transformation --- p.17 / Chapter 2.1.10 --- Validation of positive clones by polymerase chain reaction --- p.17 / Chapter 2.1.11 --- Plasmid preparation --- p.19 / Chapter 2.2 --- RNA extraction and reverse transcription polymerase chain reaction --- p.19 / Chapter 2.2.1 --- RNA extraction from cell lysate --- p.19 / Chapter 2.2.2 --- Reverse transcription-polymerase chain reaction --- p.20 / Chapter 2.3 --- Double stranded RNA-mediated gene silencing in Drosophila melanogaster Schneider cell line --- p.21 / Chapter 2.3.1 --- Maintenance of Drosophila melanogaster Schneider cells --- p.21 / Chapter 2.3.2 --- in vitro transcription of RNA --- p.22 / Chapter 2.3.3 --- Double stranded RNA purification --- p.22 / Chapter 2.3.4 --- Double stranded RNA bathing condition --- p.22 / Chapter 2.3.5 --- Transfection condition --- p.23 / Chapter 2.3.6 --- Knockdown efficiency --- p.23 / Chapter 2.4 --- Small interfering RNA-mediated gene silencing in Human Embryonic Kidney 293FT cells --- p.25 / Chapter 2.4.1 --- Maintenance of Human Embryonic Kidney 293FT cells --- p.25 / Chapter 2.4.2 --- Small interfering RNAs used in this study --- p.25 / Chapter 2.4.3 --- Transfection condition --- p.26 / Chapter 2.4.4 --- Knockdown efficiency --- p.27 / Chapter 2.5 --- Expression and purification of recombinant proteins in Escherichia coli --- p.28 / Chapter 2.5.1 --- Bacterial transformation --- p.28 / Chapter 2.5.2 --- Induction of recombinant protein expression --- p.29 / Chapter 2.5.3 --- Purification of recombinant proteins --- p.29 / Chapter 2.6 --- Glutathione S-transferase pull-down assay --- p.30 / Chapter 2.7 --- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis --- p.31 / Chapter 2.7.1 --- Protein extraction from cell lysate --- p.31 / Chapter 2.7.2 --- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis --- p.31 / Chapter 2.7.3 --- Coomassie Blue staining --- p.32 / Chapter 2.7.4 --- Silver staining --- p.33 / Chapter 2.8 --- Western blotting --- p.33 / Chapter 2.8.1 --- Electro-transfer --- p.33 / Chapter 2.8.2 --- Immunoblotting --- p.34 / Chapter 2.9 --- Fluorescence microscopy --- p.36 / Chapter 2.10 --- Confocal microscopy and time-lapse imaging --- p.36 / Chapter 2.10.1 --- General setting of time-lapse imaging --- p.36 / Chapter 2.10.2 --- Photoactivatable-GFP Nuclear Export Assay --- p.37 / Chapter 2.10.3 --- Fluorescence Lost in Photobleaching Nuclear Export Assay --- p.38 / Chapter 2.11 --- Reagents and Buffers --- p.39 / Chapter 2.11.1 --- Molecular cloning --- p.39 / Chapter 2.11.2 --- RNA extraction and reverse transcription polymerase chain reaction --- p.41 / Chapter 2.11.3 --- Bacterial culture --- p.41 / Chapter 2.11.4 --- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis --- p.43 / Chapter 2.11.5 --- Immunoblotting --- p.46 / Chapter 2.11.6 --- Expression and purification of recombinant proteins in Escherichia coli --- p.48 / Chapter 2.11.7 --- Cell culture --- p.49 / Chapter 2.11.8 --- Fluorescence microscopy --- p.50 / Chapter Chapter 3 --- Expanded Polyalanine Tract Possesses Nuclear Export Activity / Chapter 3.1 --- Expanded polyalanine tract conferred cytoplasmic localization to the nuclear export reporter protein --- p.51 / Chapter 3.1.1 --- Principle of the Rev Nuclear Export Assay --- p.52 / Chapter 3.1.2 --- Selection of polyalanine tract for the Rev Nuclear Export Assay --- p.55 / Chapter 3.1.3 --- The expanded polyalanine tract conferred cytoplasmic localization to the nuclear export reporter protein --- p.57 / Chapter 3.2 --- Expanded polyalanine tract conferred nuclear export activity on the nuclear export reporter protein by Fluorescence Loss in Photobleaching Nuclear Export Assay --- p.60 / Chapter 3.2.1 --- Principle of the Fluorescence Loss in Photobleaching Nuclear Export Assay --- p.60 / Chapter 3.2.2 --- Fluorescence intensity loss in the nuclear compartment indicates that expanded polyalanine tract possesses nuclear export activity --- p.62 / Chapter 3.3 --- The nuclear export of expanded polyalanine tract-containing nuclear export reporter protein was confirmed by Photoactivatable-GFP Nuclear Export Assay --- p.65 / Chapter 3.3.1 --- Expression of photoactivatable-GFP constructs in HEK293 cell line --- p.65 / Chapter 3.3.2 --- Principle of photoactivatable GFP (PA-GFP) Nuclear Export Assay --- p.67 / Chapter 3.3.3 --- The nuclear export activity of expanded polyalanine tract-containing nuclear export reporter protein was captured by Photoactivatable-GFP Nuclear Export Assay --- p.67 / Chapter 3.4 --- Discussion --- p.70 / Chapter Chapter 4 --- Identification of Genes That Are Involved in Nuclear Export of Expanded Polyalanine Tract-Containing Protein / Chapter 4.1 --- Screening of genes involved in nuclear export of expanded polyalanine tract containing nuclear export reporter protein in Drosophila melanogaster Schneider cells using a double-stranded RNA-mediated gene knockdown approach --- p.75 / Chapter 4.2 --- Screening of genes involved in nuclear export of expanded polyalanine tract in HEK293 cells using small interfering RNA-mediated gene knockdown approach --- p.80 / Chapter 4.3 --- Identification of expanded polyalanine tract-interacting partners by glutathione S-transferase pull-down assay --- p.84 / Chapter 4.3.1 --- Expression and purification of polyalanine tract as a glutathione S-transferase fusion protein --- p.91 / Chapter 4.3.2 --- Glutathione S-transferase pull-down assay identified three interacting proteins of expanded polyalanine tract --- p.91 / Chapter 4.4 --- Eukaryotic transcription elongation factor alpha 1 was involved in nuclear export of expanded polyalanine tract-containing nuclear export reporter protein --- p.95 / Chapter 4.4.1 --- Eukaryotic translation elongation factor 1 interacted with expanded polyalanine tract --- p.95 / Chapter 4.4.2 --- Knockdown of EEF1A expression reduced nuclear export of expanded polyalanine tract-containing nuclear export reporter protein --- p.97 / Chapter 4.5 --- Discussion --- p.101 / Chapter Chapter 5 --- General Discussion and Conclusion --- p.104 / References --- p.108
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太陽能產業上游太陽能等級多晶矽原料科技創業評估 / A technology venture evaluation case study of solar grade silicon梁博傑 Unknown Date (has links)
近幾年再生能源的議題非常的熱門,各種再生能源產業的風力發電、太陽能電池、生質能、燃料電池等產業資料,相關創業與投資訊息不斷的傳播。各種科技看起來,好像都是明日之星。對於一個要準備創業的創業家,那一個產業那一個區間才是適合的機會?在投入創業前要透過何種有效的篩選工具才能選出適當的創業機會?
本研究先從史考特‧夏恩(2005) 的科技創業聖經十個面向,再到創新者的解答與創新者的解答中的所提出的破壞性創新的觀念,先以質性研究的紮根理論探討檢視潛在創業產業及個案的可行性探討,對於經過第一階段質性研究考驗的個案,再以折價現金流量(Discount Cash-Flow)建立量化研究的財務模型,以求得資本內部報酬率(Equity Internal Return Ratio)及淨現金流量(Net Present Value)並以敏感性分析及情境分析探討財務可行性,期望找出一個創業機會能完全符合所有前訴的條件。本研究歷經三年的探討,檢視過數十個個案,包括風力發電、燃料電池、生質酒精、生質柴油、太陽能產業上中下游等創業機會,若要在台灣的環境創業又要提高創業成功機率,且又要能滿足創業團隊財務的報酬率的期望,能經過這麼多條件考驗的個案少之又少。
本研究最後選定以太陽能產業最上游的多晶矽改良式冶金法做為創業探討的個
案,最主要的原因是太陽能產業是屬於一種再生能源,有很大的機會成為長期高速成長的產業,且台灣因半導體產業及面板產業已為太陽能產業建立了基礎,多晶矽改良式冶金法又是一種破壞性創新,能提高創業成功的機會,且若在上游產業成功創業,能建立很高的進入障礙,對太陽能產業的發展佈局能具有策略性的地位。多晶矽改良式冶金法創業計畫在經過財務模型試算後,資本內部報酬率及淨現金流量,即使以改變投資條件進行創業投資的敏感性分析,或以不同情境進行探討,都能符合財務需求條件,仍能滿足創業投資的要求。 / Re-newable energy is very hot in these few years. There is lots of information mention about start-up and invest of renewable energy industry including win-power, solar-cell, bio-energy, fuel-cell. Seems every technology will be a future star industry. Which sector of what kind of re-newable energy technology will be the proper opportunity for an entrepreneur? What are effective tools to sieve the
proper start-up chance out?
This research first using quality research grounding theories, this research verify proper industry and to find out the feasibility for the specific case. The technology management theories including , Shane’s (2005)「Find Fertile Ground – Indentifying Extraordinary Opportunities for New Ventures 」 10 procedures and Christensen ( 1997) 「 The innovator’s Dilemma 」、 Christensen & Raynor (2004)
「The innovator’s Solution:The creating and sustaining successful growth 」- Disruptive innovation technology theories . When the specific case through the quality detected, go to quantity study. Th quantity study include building a finance model,calculate Discount Cash-Flow, Equity Internal Return Ratio, Net Present Value, Sensitive analysis Senarial analysis to find out the financial feasibility. This research hopes to find out a suitable star-up opportunity which could pass all the examination items of quality and quantity study. This research through three whole years to search start-up opportunities., examed dozens cases, and the industies including win-power, solar-cell, bio-energy, fuel-cell and stream sector contain
up-stream, middle-stream, down-stream After through this research process, shows that it is really hard to find out a suitable, profitable and could content the financial
expection ratio with high win-odds opportunities to run start-up.
After three years, this research finally pick up the solar upest-stream sector (modified metelology poly-silicon)as the research case.
The first reason is that solar industry belongs to re-newable energy, which has strong protenial to become a long term and high conpound growing rate industy.
The second reason:Taiwan have been developing semi- ductor and LCD industries over twenty years and built firmly industy knowledge foundation.Modified metelology poly-silicon is a disruptive innovation, could enlarge the start-up winodds.
The third reason is that to start-up in the solar industy up-stream sector could build a high barrier and keep a strategy position in the solar industry. The third reason is that the financial result will fit in with the investor’s expect.
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Etude de l'expression et de la fonction de Zac1, un facteur de transcription suppresseur de tumeursWarzée, Barbara 13 January 2011 (has links)
Zinc finger protein regulator of apoptosis and cell cycle arrest 1 (Zac1) est un facteur de transcription suppresseur de tumeurs capable, à travers des voies différentes et indépendantes, dinduire lapoptose ou larrêt du cycle cellulaire. Malgré ses implications potentielles dans le développement embryonnaire et certaines maladies telles que le cancer et le diabète néonatal, les mécanismes régulant son expression physiologique, ainsi que sa fonction biologique exacte restent méconnus. Les deux principaux objectifs de notre travail consistaient, dune part, à définir la nature des stimuli capables de moduler lexpression endogène de la protéine Zac1 et, dautre part, à étudier la fonction de Zac1. Nous avons tout dabord montré que la protéine Zac1 nétait pas exprimée dans les organes murins où lon détecte son ARN messager. Nous navons cependant pas pu mettre en évidence de mécanisme de dégradation de la protéine Zac1. Malgré ses similitudes de fonction avec le suppresseur de tumeurs p53, Zac1 nétait également pas exprimée après traitement avec des inducteurs de p53 tels que des inducteurs de dommages à lADN. Après avoir testé sans succès de nombreux stimuli pro-inflammatoires susceptibles dinduire lexpression de Zac1, nous avons finalement découvert que le variant de transcrit Zac1b était exprimé dans des fibroblastes embryonnaires murins (MEFs) traités à lacide polyriboinosinique polyribocytidylique poly(I:C), un double brin dARN synthétique. Cette régulation sest avérée être dépendante de la voie du Toll-Like Receptor 3 (TLR3) et de lInterferon Regulatory Factor 3 (IRF3), et indépendante des interférons (IFNs) de type I. Le TLR3 et IRF3 étant des activateurs centraux de limmunité antivirale, nous avons tenté de déterminer si Zac1 pourrait être impliqué dans la réponse antivirale. En rapport avec cette hypothèse, nous avons observé que Zac1b était exprimé dans des MEFs infectées avec le virus de lEncéphalomyocardite (EMCV). Nous avons également constaté que les MEFs déficientes pour Zac1 étaient moins sensibles à la mort cellulaire induite par lEMCV que les MEFs sauvages. Cependant, linactivation du gène Zac1 navait pas deffet sur la survie des souris infectées à lEMCV. En conclusion, ce travail décrit, pour la première fois, une régulation transcriptionnelle de Zac1b induite par des ARN double brin synthétiques et des virus à ARN, mais dont la signification fonctionnelle reste à découvrir. De plus, il montre que les stimuli capables dinduire p53 ninduisent pas lexpression de la protéine Zac1 suggérant que la protéine Zac1 est régulée différemment de p53.
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Synthesis of Polythiophene Derivatives on the Application of Electro-Optical DevicesPan, Jhong-Yu 19 August 2010 (has links)
Regioregular poly(3-alkylthiophenes) is a kind of conjugated polymers with HT-coupled structures . P3HT(head-to-tail) can be easy to access a low energy and low space obstacle coplanar conformation that leads to highly conjugated polymer , better conductivity and optical properties. In this research, we found out the different way of synthesis led to differences in properties such like regioregular, molecular weight. Above mentioned would influence spectrum of materials and device morphology. We chosen three kind of methods easily to synthesize from papers included FeCl3 Method, Grignard metathesis methods(Methylmagnesium bromide¡BTert-butylmagnesium chloride).
We observed the different synthetic methods we used led to different reaction and color. After the analysis, there are not only differences between regioregular and molecular weight but molecular conformation. We also noted there were some residues that could not be completely removed by ion in the polymerization process. Absorption spectrum of film is shifted showed it has different degrees of phase separation. The literature tell us that the molecular weight greatly influences the device efficiency, because it changes the morphology and that affects the mobility and Regioregular.
In this study, another field of research discusses the impact of ion. It was found after polymerization. The product not clean in the absorption spectrum of performance does not meet the solar cell requirements. After washing, it couldn¡¦t wash away the small amount of residue ion Fe, Mg, Ni, and it¡¦s about 1 ~ 3% in the total material. The experiment shows the various characteristics of different materials leads to change in device efficiency. Among them, the devices have the high molecular weight and good regioregular have the higher efficiency.
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Investigations of Photocatalyst TiO2 and Organic Light-emitting MaterialsKuo, Ming-Yu 10 July 2004 (has links)
TiO2. Structural and electronic properties of TiO2 polymorphs denser than rutile, i.e. £\-PbO2-, baddeleyite, fluorite, and cotunnite-type were calculated by a first-principle pseudo-potential method based on density functional theory with local density approximation. Using experimental and theoretical lattice parameters of ambient TiO2, i.e. anatase and rutile as standard, the fluorite-type TiO2 has the narrowest band gap among the post-rutile phases. This character is important for the potential applications as visible-light-responsive photocatalyst.
In additional to the bulk properties of dense TiO2 polymorphs the surface energies of
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Electrical Properties and Reliability of Poly-Si TFTs for System On Panel ApplicationWeng, Chi-Feng 23 June 2009 (has links)
English Abstract
In this thesis, we investigate the electrical properties and reliabilities of poly-Si TFTs for system on panel application. Roughly, we divide the thesis into two parts, n-type and p-type TFTs respectively. In n-type TFT, we mainly study degradation characteristics of TFTs under dynamic stress. On the other hand, we focus on special negative bias temperature instability (NBTI) degradation for p-type poly-Si TFTs. Because grain boundary in poly-Si film and serious self-heating effect due to glass substrate, which has a poor thermal conductivity, the electrical properties and reliabilities of poly-Si TFTs become more complicated, compare with metal-oxide-semiconductor field effect transistor (MOSFET). Therefore, in the thesis, we found some strange phenomena never observed in a-Si TFT and MOSFET.
In chapter 3, the degradation mechanism of n-channel poly-silicon thin film transistor (poly-Si TFT) has been investigated at room temperature under dynamic voltage stress, which simulate under high frequency operation as driving devices. The ON-current of TFT is degraded to as low as 0.3 times of the initial value after 1000 second stress. On the other hand, both the sub-threshold swing and threshold voltage kept well during the AC stress. The current crowding effect was rapidly increased with increasing of stress duration. However, comparing the initial and degraded characteristics at rising temperature, namely, 150◦C, the ON-current of TFT only decrease to 75 percent of the initial value after 1000 second AC stress. It depicts that creation of effective trap density in tail-states of poly-Si film is responsible for the electrical degradation of poly-Si TFT. At high temperature, electron has enough energy to pass the energy barrier created by ac stress and the degradation is less obvious.
In chapter 4, the degradation mechanism of n-channel poly-silicon thin film transistor (poly-Si TFT) has been investigated under dynamic voltage stress, which simulate under low frequency operation as pixel switches. Surprisingly, two totally different degradations of TFTs were observed after dynamic stress. Firstly field-effect mobility and driving current increased during early stress. However, a clear and rapid degradation of field-effect mobility occurred instead during later stress. Additionally, the threshold voltage of stressed TFTs strangely shifted to negative direction in later stress, which was never observed in early stress. Finally, we clarify the degradation mechanisms for early and later stress respectively by varied temperature experiments.
In chapter 5, the characteristics of p-type poly-silicon thin film transistor (poly-Si TFT) with dynamic bias stress were investigated. The AC stress is operated with the constant drain voltage (15V) and the varying gate voltage (0V~-15V) to degrade the devices. There are some phenomena which cannot be completely explained by typical NBTI mechanism in the experiment. In addition to NBTI, we suggest that the self-heating effect might be involved, because the self-heating effect could rise channel temperature and cause the dissociation of the Si-H bonds at the poly-Si/SiO2 interface due to the Joule heating. The released hydrogen reacts with SiO2 and causes the fixed charge in the gate oxide. Thus, the degradation of electrical characteristics of device is mainly dominated by the self-heating induced NBTI effect.
In chapter 6, we investigate the asymmetric negative bias temperature instability degradation of poly-Si TFTs. Electric measurements of normal and reverse modes were employed to analyze the degradation on Vt, current, leakage current and sub-threshold swing (S.S.). The results indicated that a non-uniform vertical electric field at the poly-Si/SiO2 resulted in asymmetric negative bias temperature instability degradation. The trap generation was a grading distribution from source to drain. Moreover, some energy diagrams were proposed to explain the experimental data. Sequentially, asymmetric TFT degradation resulted from a grading distribution of trap state induced by asymmetric NBTI.
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Radiopurity measurement of acrylic for the DEAP-3600 dark matter experimentNantais, Corina 16 January 2014 (has links)
The liquid argon target of the DEAP-3600 dark matter detector is contained by an extremely radiopure acrylic vessel. Alpha decays from the inner surface of the acrylic vessel are a source of background. If a fraction of the alpha energy is observed, or if the recoiling nucleus from the alpha decay is observed, the event will not be separated from a dark matter candidate event. In addition to the low level of inherent contamination from uranium and thorium, the Pb-210 from Rn-222 diffusion during manufacturing must be measured. The limit for the DEAP-3600 acrylic vessel is 1.1 × 10^−20 g/g Pb-210. By vaporizing a large quantity of acrylic and counting the concentrated residue with an ultralow background HPGe well detector and a low background alpha spectrometer, the bulk acrylic was found to have an upper limit of 10^−19 g/g Pb-210. The design, installation, commissioning, operation, and analysis for various aspects of the acrylic assay are described. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2014-01-14 19:27:47.533
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Dielectric relaxation behavior of poly(3-hydroxybutyrate) /Park, Taigyoo, January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 136-141). Also available via the Internet.
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Identification de la nucléoline comme protéine pouvant interagir avec la poly(ADP-ribose) polymérase-1 par spectrométrie de masse et caractérisation de cette association par bioluminescence resonance energy transfer (BRET) /Bouchard, Véronique. January 2003 (has links)
Thèse (M.Sc.)--Université Laval, 2003. / Bibliogr.: f. 77-93. Publié aussi en version électronique.
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