Dissertations / Theses on the topic 'Reactive wires'
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Joyce, Karen Elaine. "Development of Reactive Ion Scattering Spectrometry (RISS) as an Analytical Surface Characterization Technique." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193593.
Full textPozuelo, Ruiz Marta. "Bioengineering single-protein wires." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/462906.
Full textLa transferencia de electrones (ET) es uno de los procesos más importantes de la vida. La comprensión fundamental de los procesos de ET en biología es importante no sólo para comprender tales procesos naturales claves, sino también para avanzar en el diseño de interfaces biomolécula / electrodo para aplicaciones bioelectrónicas. En particular, se ha explotado la microscopía de efecto túnel con control electroquímico (EC-STM) para monitorizar in situ la constante de ET en función del potencial aplicado de las metaloproteínas. La Azurina de Pseudomonas aeruginosa es un modelo de proteína redox ampliamente estudiado, tanto en ‘bulk’ como a nivel de una sola proteina. Su estructura globular contiene un ion de cobre coordinado, que hace que la proteína sea capaz de intercambiar electrones cambiando su estado redox (Cu I/II). Este ion es el responsable de su rol como portador de electrones en la cadena respiratoria de las bacterias. En esta tesis, mostraremos nuestros avances en el diseño y caracterización de dispositivos de una sola proteína utilizando un modelo de metaloproteína Cu-Azurin. Hemos demostrado un comportamiento similar a un transistor en un hilo electroquímico de una sola proteína que funciona a muy bajos voltajes gracias a las propiedades redox de Cu-Azurin. Se demostró que la conductancia varía dependiendo del estado redox del centro de Cu, teniendo su valor máximo en el punto medio redox. También hemos analizado la formación espontánea de los contactos eléctricos de Azurin única a través de la corriente monitorizada cuando los dos electrodos ECSTM se colocaron a una distancia fija. Se observaron eventos discretos de conmutación para la conductancia, cuya frecuencia depende de las condiciones electroquímicas aplicadas y, por lo tanto, se atribuyeron unívocamente cambios discretos en el estado redox de la proteína atrapada. Con el fin de adaptar el comportamiento de transporte de carga de la unión uniproteica, hemos sintetizado varios mutantes de la misma proteína mediante bioingeniería en diferentes posiciones de la proteína. Nuestros resultados muestran que podemos cambiar racionalmente el mecanismo de transporte del dispositivo de una sola proteína mediante el estudio del efecto de la modificación de residuos específicos en las vías ET particular en el esqueleto de la proteína.
Kumar, Pawan. "Studies of wire-matrix interaction in some tungsten wire reinforced stainless steels." Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/8980.
Full textÖktem, Gözde. "Oligo(3-hexylthiophene) Wires for needs of Single-Molecule Nanoelectronics." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227736.
Full textFowler, Matthew R. "Testing and Evaluation of a Novel Virtual Reality Integrated Adaptive Driving System." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1634.
Full textNagy, Péter. "Formation and Decomposition of Platinum–Thallium Bond, Kinetics and Mechanism. Structural Characterization of Some Metal Cyanides in the Solid State." Doctoral thesis, KTH, Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3803.
Full textThe kinetic and mechanistic features of a new series ofplatinum-thallium cyano compounds containing a direct andunsupported by ligands metal-metal bond have been studied insolution, using standard mixandmeasurespectrophotometric technique and stoppedflow method.These reactions are interpreted as oxidative addition of the cspecies to the square planar Pt(CN)42-complex. Each of these processes was found to befirst-order in Pt(CN)42-, the corresponding TIIIIcomplex and a cyanide ion donating species whichacts as a catalyst. Both di- and trinuclear complexes werestudied, and the kinetically significant thallium complexes intheir formation and the catalytically active cyanide sourcesare as follows: [(CN)5PtTl(CN)3]3-: Tl(CN)4(alkaline region), Tl(CN)3(slightly acidic region) and CN; [(CN)5PtTl(CN)]: Tl(CN)2+and Tl(CN)2+; [(CN)5PtTlPt(CN)5]3-: [(CN)5PtTl(CN)]and HCN. Appropriatemechanisms were postulated for the overall reactions in allcases, which include i) metalmetal bond formation stepand ii) coordination of an axial cyanide ion to the platinumcenter. Two experimentally indistinguishable kinetic modelswere proposed for the formation of the dinuclear complexeswhich are different in the sequence of the two steps. In thecase of the trinuclear complex, experimental evidence isavailable to exclude one of the alternative reaction paths, andit was proven that the metalmetal bond formation precedesthe axial cyanide coordination.
The cyanide ligands coordinated to TIIIIin the PtTl complexes could be replacedsuccessfully with aminopolycarboxylates e.g.: mimda2-, nta3-, edta4-. The [(CN)5PtTl(edta)]4-complex, with a direct metalmetal bond hasbeen prepared in solution by two different reactions: a)dissolution of [(CN)5PtTl](s) in an aqueous solution of edta, b)directly from Pt(CN)42-and Tl(edta)(CN)2-. The decomposition reaction is greatlyaccelerated by cyanide and significantly inhibited by edta. Itproceeds through the [(CN)5PtTl(CN)3]3-intermediate. The formation of [(CN)5PtTl(edta)]4-can proceed via two different pathways dependingon the ratio of the cyanide to the edta ligand concentrations.Thedirect pathat excess of edta means theformation of intermediate[(CN)4Pt···Tl(CN)(edta)]4-, followed by a release of the cyanide from theTlcentre followed by coordination of a cyanide from thebulk to the Ptcentre of the intermediate. Theindirect pathdominates in the absence of extraedta and the formation of the PtTl bond occours betweenPt(CN)42-and Tl(CN)4.
Homoligand MTl(CN)4(M = TlI, K, Na) and, for the first time, Tl(CN)3species have been synthesized in the solid stateand their structures solved by single crystal Xraydiffraction method. Interesting redox processes have been foundbetween TIIIIand CNin nonaqueous solution and in Tl2O3-CNaqueous suspension. In the crystal structureof Tl(CN)3·H2O, the thallium(III) ion has a trigonal bypiramidalcoordination geometry with three cyanides in the trigonalplane, while an oxygen atom of the water molecule and anitrogen atom from a cyanide ligand attached to a neighboringthallium complex, form a linear OTlN fragment.Cyanide ligand bridges thallium units forming an infinitezigzag chain structure. Among the thallium(III) tetracyanocompounds, the isostructural M[Tl(CN)4](M = Tl and K) and Na[Tl(CN)4]·3H2O crystallize in different crystal systems, but thethallium(III) ion has in all cases the same tetrahedralgeometry in the [Tl(CN)4]unit.
Three adducts of mercury(II) (isoelectronic with TIIII) (K2PtHg(CN)6·2H2O, Na2PdHg(CN)6·2H2O and K2NiHg(CN)6·2H2O) have been prepared from Hg(CN)2and square planar transition metal cyanides MII(CN)42-and their structure have been studied by singlecrystal Xray diffraction, XPS and Raman spectroscopy inthe solid state. The structure of (K2PtHg(CN)6·2H2O consists of strictly linear one dimensional wireswith PtIIand HgIIcenters located alternately, dHgPt= 3.460 Å. The structure of Na2PdHg(CN)6·2H2O and K2NiHg(CN)6·2H2O can be considered as double salts, the lack ofheterometallophilic interaction between both the HgIIand PdIIatoms, dHgPd= 4.92 Å, and HgIIand NiIIatoms, dNiPd= 4.60 Å, seems obvious. Electronbinding energy values of the metallic centers measured by XPSshow that there is no electron transfer between the metal ionsin all three adducts. In solution, experimental findingsclearly indicate the lack of metalmetal bond formation inall studied HgIICN-MII(CN)42-systems (M = Pt, Pd and Ni). It is in contrary tothe platinumthallium bonded cyanides.
KEYWORDS:metalmetal bond, platinum, thallium,kinetics, mechanism, stopped flow, oxidative addition, cyanocomplexes, edta, redox reaction, metal cyanides, Xraydiffraction, Raman, NMR, mercury, palladium, nickel, onedimensional wire
Santos, Mickael da Costa. "Study of the influence of high hydrostatic pressure on wine chemical and sensorial characteristics." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14822.
Full textDuring the last years, the use of high hydrostatic pressure (HHP) as a non-thermal technology for preservation or aging of wine has increased substantially in the academic community. However, HHP treated wine has been only analysed after the pressure treatment, with no knowledge available on the effects of HHP during subsequent storage. The results presented in this thesis showed that HHP treatments influence the chemical and sensorial properties of wine during storage. The application of high hydrostatic pressure treatments in winemaking for wine preservation, as an alternative to sulphur dioxide, was evaluated studying the effect of HHP in the physicochemical and sensorial properties of red and white wines during bottle storage. High pressure treatments with 5 min of processing time and pressures of 425 and 500 MPa were shown to influence on both red and white wine physicochemical and sensorial characteristics. However, the effects were only perceptible after, at least, 6 months of storage. The alterations that occurred on the pressurized red wine characteristics, such as the more orange-red colour and the lower antioxidant activity (15-27% less), total phenolic content (9% less), and anthocyanins content (45–61% less), were due to an increase of condensation reactions of phenolic compounds. The increase of these condensation reactions lead to the formation of compounds with higher degree of polymerisation that became insoluble along storage, increasing consequently the amount of wine deposits in the pressurized wines. In terms of white wines, pressurized wines showed, after one year of storage, a more brownish colour and a lower antioxidant activity (15% less) and total content of phenolic compounds (10% less) when compared to the unpressurized wines. These results, together with the lower content of free amino acids (15-20% less) and higher content of furans (up to 70% more), present in the pressurized wines after nine months of storage, led to propose an effect of HHP treatments in the acceleration of Maillard reactions that occur during the wine storage period. Therefore, contrary to the pressurized sulphur dioxide-free red wine, the pressurized white wines were not considered suitable for commercialization as table wines due to the higher brownish colour and cooked fruit aroma, characteristics of an aged or thermally treated wine.Additionally, the impact of the pressure treatments on the volatile composition of sulphur dioxide-free red and white wines, during bottle storage, was evaluated. More than 160 volatile compounds, distributed by 12 chemical groups, were identified in both wines. At the end of storage, the pressurized wines presented a higher content of furans, aldehydes, ketones, and acetals when compared to the unpressurized wines. These results indicate that pressure influences the white and red wine long term volatile composition, being this particularly evident for longer storage periods. The changes on the volatile composition of the pressurized wines, indicated that the HHP treatments accelerate the Maillard reactions, and the oxidation of alcohols and fatty acids, leading to wines with a volatile composition network approaching the characteristic of faster aged and/or thermally treated wines. The acceleration of Maillard reactions and phenolic compounds condensation by HHP treatments was also studied in model wine solutions (hydro alcoholic solution at acidic pH). The results showed that the high pressure treatment accelerated the Maillard reaction and this effect was quantifiable, mainly, after 6 months of storage. Pressurized model solutions presented higher concentration of 2-furfural, phenylacetaldehyde and benzaldehyde, when compared to the controls. In terms of phenolic compounds condensation reactions, the pressurized model wine solutions showed no relevant differences, when compared to controls. Therefore, it seems that the pressure treatment had a higher impact in terms of kineticks of reactions and in less extent in terms of different compounds formed. Lastly, the application of HHP treatments in winemaking to improve the properties of young wines was evaluated. For this propose, the effect of HHP treatments in the phenolic composition of a red wine was studied and compared with the effect of different oenological practices. Wines pressurized at 500 MPa for 5 min, and 600 MPa for 20 min, at 20 ºC, showed, after 5 months of storage, a lower monomeric anthocyanins (8-14%), phenolic acids (8-11%) and flavonols (14-22%) content, when compared to the unpressurized ones. The wine pressurized at 500 MPa presented a flavanols content and a degree of polymerization very similar to the wines treated by traditional aging processes. In terms of sensorial properties, the pressure treatments increased the cooked fruit aroma and decreased the floral and fruit odours and, in the case of the 600 MPa treatment, increased the bitterness. Therefore, the HHP treatments seem to promote reactions that are similar to those observed in wines treated with wood aging processes. In conclusion, the results presented in this thesis showed that HHP treatments accelerated the Maillard reaction and the polymerization reactions between phenolic compounds present in the wine, influencing the chemical and sensorial properties of wine. HHP can be potentially used to preserve or accelerate the wine aging process, producing wines with pleasant and distinct characteristics.
Durante os últimos anos, o uso de alta pressão hidrostática (APH) como tecnologia não-térmica para a preservação ou envelhecimento de vinho tem aumentado substancialmente na comunidade académica. No entanto, os vinhos tratados por APH têm sido analisados após o tratamento de pressão, não havendo referências sobre as suas propriedades durante o armazenamento. Os resultados apresentados nesta tese mostram que a aplicação de tratamentos de APH altera as propriedades químicas e sensoriais de vinhos ao longo do armazenamento. Os tratamentos de alta pressão hidrostática foram aplicados na vinificação para a preservação de vinho, como alternativa ao dióxido de enxofre, sendo o seu efeito avaliado nas propriedades físico-químicas e sensoriais de vinhos tintos e brancos durante o armazenamento em garrafa. Os tratamentos de alta pressão com 5 min de processamento e pressões de 425 e 500 MPa mostraram influenciar as características físico-químicas e sensoriais de vinhos tintos e brancos. No entanto, o efeito foi apenas percetível após pelo menos 6 meses de armazenamento. As alterações que ocorreram nas características do vinho tinto pressurizado, tais como a cor mais laranja-vermelho, menor atividade antioxidante (menos 15 a 27%), menor conteúdo de compostos fenólicos totais (menos 9%) e menor teor de antocianinas (menos 45-61%), foram devidas a um aumento das reacções de condensação de compostos fenólicos. O aumento destas reações de condensação levou à formação de compostos com maior grau de polimerização que se tornaram insolúveis no vinho ao longo do armazenamento, aumentando consequentemente a quantidade de depósito nos vinhos pressurizados. Em relação ao vinho branco, os vinhos pressurizados mostraram, depois de um ano de armazenamento, uma cor mais acastanhada, menor atividade antioxidante (menos 15%) e menor teor de compostos fenólicos totais (menos 10%) comparando com os vinhos não pressurizados. Estes resultados, juntamente com o baixo teor de aminoácidos livres (menos 15 a 20%) e um maior teor de furanos (até 70% mais) para os vinhos pressurizados após nove meses de armazenamento, levam a propor que os tratamentos de APH aceleraram as reações de Maillard que ocorrem durante o período de armazenamento do vinho. No entanto, ao contrário dos vinhos tintos pressurizados, os vinho brancos pressurizados não foram considerados adequados para comercialização como vinhos de mesa, visto que apresentavam uma cor acastanhada e um elevado aroma a fruta cozida, características estas de vinhos envelhecidos ou tratados termicamente.Adicionalmente, foi avaliado o impacto dos tratamentos de APH sobre a composição volátil dos vinhos tintos e brancos sem dióxido de enxofre durante o armazenamento em garrafas. Mais de 160 compostos voláteis, distribuídos por 12 grupos químicos, foram identificados em ambos os vinhos. No final do armazenamento, os vinhos pressurizados apresentaram um teor mais elevado de furanos, aldeídos, cetonas e acetais quando comparados com os vinhos não pressurizados. Estes resultados indicam que os tratamentos de APH influenciam a composição volátil de vinhos brancos e tintos, , sendo mais evidente em longos períodos de armazenamento. As mudanças na composição volátil dos vinhos indicaram que os tratamentos de APH aceleraram as reações de Maillard e também a oxidação de álcoois e ácidos gordos, originando vinhos com uma composição volátil próxima de vinhos com envelhecimento acelerado ou tratados termicamente. A aceleração das reações de Maillard e de polimerização dos compostos fénolicos causada pelos tratamentos de APH foi também estudada em soluções modelo de vinho (solução hidroalcoólica com pH ácido). Os resultados mostraram que o tratamento de APH acelera a reação de Maillard , sendo este efeito quantificado, apenas, após 6 meses de armazenamento. As soluções modelo de vinho pressurizadas apresentaram concentrações mais elevadas de 2-furfuraldeído, fenilacetaldeído e benzaldeído, em comparação com os controlos. Em termos de polimerização dos compostos fénolicos, as soluções modelo pressurizadas não apresentaram diferenças relevantes, em comparação com os controlos. Por conseguinte, os tratamentos de APH aparentem ter mais impacto em termos de modificações nas cineticas de reação do que na formação de novos compostos. Por último, a aplicação de tratamentos de APH foi estudada para melhorar as propriedades de vinhos jovens. Para este propósito, o efeito de tratamentos de APH na composição fenólica de um vinho tinto foi estudado e comparado com o efeito de diferentes práticas enológicas. Vinhos pressurizados a 500 MPa durante 5 min e a 600 MPa durante 20 min, a 20 ºC, mostraram depois de 5 meses de armazenamento um menor teor de antocianinas monoméricas (8-14%), ácidos fenólicos (8-11%) e flavonóis (14 -22%), quando comparados com os vinhos não-pressurizados. O vinho pressurizado a 500 MPa apresentou um teor de flavonóis e um grau de polimerização de taninos muito semelhante aos vinhos tratados por processos de envelhecimento tradicionais. Em termos de propriedades sensoriais, os tratamentos de pressão aumentaram o aroma de fruta cozida e diminuiram os aromas florais e frutados, tendo no caso do tratamento de 600 MPa sido verificado também um aumento da amargura. Assim sendo, os tratamentos de APH parecem promover reações que são semelhantes às observadas em vinhos tratados com processos de envelhecimento em madeira. Em conclusão, os resultados apresentados nesta tese mostram que a aplicação de tratamentos de APH acelera as reações de Maillard e a polimerização dos compostos fenólicos presentes no vinho, ao longo do armazenamento, alterando assim as propriedades químicas e sensoriais dos vinhos. A APH pode ser potencialmente utilizada para preservar ou acelerar o processo de envelhecimento de vinho tinto produzindo vinhos com características agradáveis e distintas.
Müller, Wolfhart. "Temperaturverhältnisse und Reaktionskinetik beim Ziehen und Wärmebehandeln von Draht." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-127084.
Full textBijjula, Kowtilya. "Gaseous reactive flows around catalytically combusting micro-wires /." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337702.
Full textSource: Dissertation Abstracts International, Volume: 69-11, Section: B, page: 7089. Adviser: Dimitrios C. Kyritsis. Includes bibliographical references (leaves 107-117). Available on microfilm from Pro Quest Information and Learning.
Silva, Gabriel Santos da. "Otimização da deposição de filmes multicamada reativos sobre fios de tungsténio." Master's thesis, 2019. http://hdl.handle.net/10316/96219.
Full textO trabalho de investigação realizado teve por objetivo otimizar o revestimento de fios de tungsténio com filmes multicamada reativos, por forma a promover uma reação autopropagável entre Ni e Al (ou Ti), com a consequente libertação de calor. O objetivo final é utilizar este calor para fundir um material de baixo ponto de fusão, e assim bloquear a propagação de fendas em materiais metálicos.Filmes multicamada Ni/Al e Ni/Ti foram produzidos por pulverização catódica magnetrão, utilizando dois alvos distintos. Como substratos foram utilizados fios de tungsténio com diâmetros de 0,5, 0,2 e 0,05 mm. As deposições foram efetuadas de modo a obter filmes multicamada com composição química global equiatómica e períodos de modulação (espessura da bicamada) nanométricos (25 e 50 nm). De forma a otimizar o revestimento de fios, foi desenvolvido um novo porta substratos. A secção transversal dos filmes foi analisada por microscopia eletrónica de varrimento e transmissão, após deposição e após ignição por descarga elétrica de 9V.A redução das potências aplicadas aos alvos e a utilização do novo porta substratos permitiram evitar/reduzir os defeitos observados nos filmes Ni/Al. Nos filmes Ni/Ti não foram observados defeitos. Ao fazer passar corrente através de um fio de W com 0,05 mm de diâmetro, revestido com um filme Ni/Al com 25 nm de período, foi observado um “flash” e confirmada a ocorrência de uma reação autopropagável. Concluindo, neste estudo foram desenvolvidos fios de W revestidos com filmes multicamada reativos com potencial para aplicação em autorreparação.
The aim of this research work was to optimize the coating of tungsten wires with reactive multilayer thin films in order to promote a self-propagating reaction between Ni and Al (or Ti), with consequent heat release. The ultimate goal is to use this heat to melt a low melting point material, and thus block crack propagation in metallic materials.Ni/Al and Ni/Ti multilayer films were produced by magnetron sputtering using two different targets. Tungsten wires with diameters of 0.5, 0.2 and 0.05 mm were used as substrate material. The depositions were carried out in order to obtain multilayer thin films with equiatomic overall chemical composition and nanometric modulation periods (bilayer thickness, 25 and 50 nm). In order to improve the coating of wires, a new substrate holder has been developed. The cross section of the films was analyzed by scanning and transmission electron microscopy, after deposition and after ignition by an electric discharge of 9V.The reduction of the power applied to each target and the use of the new substrate holder allowed the defects observed in Ni/Al thin films to be avoided/reduced. Ni/Ti thin films showed no defects. When passing current through a 0.05 mm diameter W wire coated with a 25 nm period Ni/Al film, a flash was observed and the occurrence of a self-propagating reaction confirmed. In conclusion, in this study W wires coated with reactive multilayer thin films with potential for self-healing applications were developed...................
Li, Yi-De, and 李奕德. "Study on Multi-Wire Reactive Electrophoretic Diamond Wire Sawing Process of Single-Crystalline Sapphire Wafers." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/crnjyh.
Full text國立臺灣科技大學
機械工程系
106
Single crystal sapphire is a highly transmissive, high temperature resistant, and high hardness brittle semiconductor material, but with a good lattice matching with GaN for solid-state illumination. Diamond Wire Sawing (DWS) is usually used in the production of single crystal sapphire wafer for LED substrates. This research aims to develpe a multi-wire reactive electrophoresis DWS and apply SiO2 particles to generate a solid-phase chemical reaction (SPCR) with sapphire and then create the deposition of SiO2 powder coating by electrophoresis deposition during the diamond wire sawing process. For process mechanism, the reacting abrasive first convert the sapphire surface into a softer reaction layer, then the softened layer can be removed by diamond grits on the diamond wire. In this study, a single-wire saw cutting machine has been modified from previous study and used to finish wire sawing of two-inch sapphire wafers to verify the solid-phase chemical reaction. Moreover, the EPD-SDWS process has been converted into an experimental multi-wire saw machine to compare the difference with rocking motion. Experimental results show that the SPCR can reduce surface roughness of as-cut sapphire wafer Sa as 26% and Ra as 42%. Also the shape of chips can be obviously changed from granular to strip type. The rocking motion assisted process can reduce the contact length by 49% and increase the material removal rate (MRR) by 29%. Moreover, surface quality and sub-surface damage can be improved. Results of this study can be future applied on development of high efficient multi-wire sawing process of related semiconductor material process.
Lai, Yen-An, and 賴彥安. "Photocatlytic Reaction in Heterostructured ZnO Nano-Particles/Silver Nano-Wires Composites." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/57249982853633315158.
Full text中原大學
奈米科技碩士學位學程
103
Zinc oxide (ZnO) is one of the most popular semiconductor materials in recent years. In this study, we synthesized zinc oxide nano-particles (ZnO NPs) by the typical sol-gel method with ultrasonic treatment to avoid particle aggregation In the first part of this thesis, we discussed how the molecular weights (NW) of polyvinyl pyrrolidone (PVP), which was used as a protecting agent in the synthesis, affect the ZnO NPs size and the oxygen vacancies in ZnO structure. We characterized the ZnO NPs by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), photoluminescence (PL), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), Raman spectroscopy, etc. Next, we chose PVP MW ~ 8K to synthesize the optimized ZnO NPs. Then we combined ZnO NPs and silver nano-wires (Ag NWs) into heterostructured nano-composites with a UV light treatment. In this step, we also characterized the samples by TEM, SEM, PL, UV-vis, EDS, XRD, etc. The last as well as main purpose of this thesis is to study the photo-catalysis reaction with our ZnO / Ag nano-composites. The degradation of the organic pollutant methyl blue (MB) was used to evaluate the photo-catalytic efficiency. We compared the photo-catalytic efficiency of the pure ZnO samples synthesized by different PVP molar weights and the ZnO/Ag nano-composites.
Lin, Yi-Zhen, and 林宜貞. "A Study of Reinforcing Effect by Using Reactive Powder Concrete and Wire Mesh." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/84275050529396002041.
Full text東南技術學院
防災科技研究所
94
The purpose of this study is to investigate the effects of confinement by using Reactive Powder Concrete(RPC)and wire mesh, together, to reinforce the compression member. The plain concrete specimen is used as the compression member. And three different reinforcing methods are used:1) one layer of wire mesh and 5mm thick of RPC, 2) two layers of wire mesh and 10mm thick of RPC, 3) three layers of wire mesh and 15mm thick of RPC. The RPC and wire mesh is placed at the outer ring of the plain concrete specimen to provide confinement to the specimen. The result of our study shows the compression strengths of the reinforced specimens increase 35﹪, 47﹪and 86﹪respectively, for each reinforcing method, when compared to the strength of the un-reinforced specimen. In addition to the increase in compression strength, the reinforced specimens also show a tremendous increase in ductility. For example, the length of the specimen decreases 20mm in compression test before failure occurred, if it is reinforced with three layers of wire mesh and 15mm thick of RPC.
Zhang, Yongchao Heller Adam. "Amperometric DNA sensing using wired enzyme based electrodes." 2003. http://wwwlib.umi.com/cr/utexas/fullcit?p3122806.
Full textLai, Shu-Ping, and 賴淑萍. "Low Operating Temperature POM Reaction Micro-Methanol Reformer with Silicon Nano-Wires Supported Nano-Catalysts." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/46805326716214469504.
Full text國立清華大學
工程與系統科學系
99
In this paper, we proposed a new design of a high performance methanol micro-reformer for hydrogen production which integrated low temperature catalysts supported by silicon nano-wires inside micro-channels with multi-inlet and in-parallel channel. Without complicated fabrication process, the reforming performance of micro-reformer with Si nano-wire fully filled channel-passageways in height and length compared to that without nano-wires supported can enhanced by 38 folds more hydrogen yield;and the hydrogen yield at 180 oC and 250 oC are 8.8×10-7 mole/min and 1.5×10-6 mole/min, respectively. The enhancement of this new design micro-reformer was attributed to (1) the large surface area that the Si nano-wires can provided,(2) hard membrane photoresist process which assisted in better catalytic coating morphology,(3) the special design of Si nano-wires fully filled channel-passageways in height and length was expected to be able to force reactive-gases contact with catalysts,(4) the detailed discussions of how the different ingredients in catalysts solution influence the catalytic coating morphology。
Dong, S., D. Zhou, Ashraf F. Ashour, B. Han, and J. Ou. "Flexural toughness and calculation model of super-fine stainless wire reinforced reactive powder concrete." 2019. http://hdl.handle.net/10454/17173.
Full textAs a type of excellent reinforcing filler, super-fine stainless wire (SSW) can form widely distributed network in reactive powder concrete (RPC) to transfer crack tip stresses as well as inhibit the initiation and propagation of cracks, leading to significant improvement of flexural toughness of RPC. In this paper, the flexural toughness of RPC beams and plates reinforced with 1% and 1.5% by vol. of SSWs was investigated, and its calculation model was established according to the composite material theory. Experimental results showed that the flexural toughness of unnotched beams fabricated with RPC containing 1.5% SSWs is 146.5% higher than that of control RPC without SSWs according to load-deflection relationships. The equivalent flexural strength of notched RPC beams is enhanced by 80.0% as SSW content increases from 1% to 1.5%. The limitation ability of SSWs on crack mouth opening can be used to evaluate the flexural toughness of composites. An addition of 1.5% SSWs leads to 201.9% increase of flexural toughness of RPC plates in accordance with load-deflection relationships. The calculation model based on the composite material theory can accurately describe the toughening effect of SSWs on RPC beams and plates. The enhancement of flexural toughness of RPC caused by SSWs is beneficial for improving the safety of structures as well as broadening the engineering applications of composites.
National Key Research and Development Program of China (2018YFC0705601) and China Postdoctoral Science Fundation (2019M651116).
Dong, S., X. Dong, Ashraf F. Ashour, B. Han, and J. Ou. "Fracture and self-sensing characteristics of super-fine stainless wire reinforced reactive powder concrete." 2019. http://hdl.handle.net/10454/17126.
Full textSuper-fine stainless wire (SSW) can not only form widely distributed enhancing, toughening and conductive network in reactive powder concrete (RPC) at low dosage level, but also improve weak interface area and refine cracks due to its micron scale diameter and large specific surface. In addition, the crack resistance zone generated by SSWs and RPC matrix together has potential to further enhance the fracture properties of composites. Therefore, fracture and self-sensing characteristics of SSW reinforced RPC composites were investigated in this paper. Experimental results indicated that adding 1.5 vol. % of SSW leads to 183.1% increase in the initial cracking load of RPC specimens under three-point bending load. Based on two parameter fracture model calculations, an increase of 203.4% in fracture toughness as well as an increase of 113.3% in crack tip opening displacement of the composites reinforced with 1.5% SSWs are achieved. According to double-K fracture model calculations, the initiation fracture toughness and unstable fracture toughness of the composites are enhanced by 185.2% and 179.2%, respectively. The increment for fracture energy of the composites reaches up to 1017.1% because of the emergence of blunt and tortuous cracks. The mixed mode Ⅰ-Ⅱ fracture toughness of the composites is increased by 177.1% under four-point shearing load. The initial angle of mixed mode Ⅰ-Ⅱ cracks of the composites decreases with the increase of SSW content. The initiation and propagation of cracks in the composites can be monitored by their change in electrical resistivity. The excellent fracture toughness of the composites is of great significance for the improvement of structure safety in serviceability limit states, and the self-sensing ability of the composites can also provide early warning for the degradation of structure safety.
National Key Research and Development Program of China (2018YFC0705601), the National Science Foundation of China (51578110), China Postdoctoral Science Fundation (2019M651116) and the Fundamental Research Funds for the Central Universities in China (DUT18GJ203).
Zhang, Yongchao. "Amperometric DNA sensing using wired enzyme based electrodes." Thesis, 2003. http://hdl.handle.net/2152/1090.
Full textChen, Guan-Lin, and 陳冠霖. "Study on Reactive Electrophoretic Diamond Wire Sawing Process of Crystalline Si Substrates for Solar Cell Application." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/01313780476187079967.
Full text國立臺灣科技大學
機械工程系
103
Solar cells have been one of the most important alternative energy for many years. However, efficiency and energy exhaustive of fabrication silicon substrates have always been a major problem in promotility such green products. This study develops a Reactive Electrophoretic Diamond Wire Sawing (REP-DWS) to slice first time, which integrates both Diamond Wire Sawing (DWS) and Slurry Wire Sawing (SWS) with Solid Phase Chemical Reaction (SPCR) to be a novel slicing process of silicon substrates. Calcium carbonates are used as reactive abrasive to soften the surface of silicon ingot with solid-state reaction layer and then removed by diamond abrasive to improve the Material Removal Rate (MRR). Tests of contact angle, Vickers indentation and XPS have been used to verify the existence of reaction layer. In this study, REP-DWS single-wire saw test machine has been remodeled, for experimental parameters, using voltage 25V and slurry with 30wt% CaCO3 concentration can improve surface roughness about 6% and reduce surface saw marks of sliced substrates about 57%. Then a commercial multi-wire saw experimental apparatus has been retrofitted, for experiments of results, REP-DWS can increase MRR about 13% and reduce the wear of diamond grits on wire by 59% as compared with DWS. The REP-DWS process improves saw marks on surface and also reduce sub-surface crack. Results of this study can be further develop of multi-wire saw process.
Zheng-XueTsai and 蔡政學. "The Interfacial Reaction on Pd-Coated Cu Wire Bonds Under Current Stressing." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/87407535661362624100.
Full text國立成功大學
材料科學及工程學系碩博士班
100
The influence of palladium in the interfacial reactions of copper wire bonding under current stressing is reported in this study. At the as-bonded step, Pd dissolved into a Cu ball bond and then gathered at the edge of the Cu ball, forming an anti-oxidation layer. The growth rate of IMCs under current stressing depends on the type of wire bonds and the direction of the current. The interfacial reaction at the anode, where electrons flow from Cu wire bonds to the Al pad, is faster than that of the cathode, where electrons flow from the Al pad to Cu wire bonds. This is probably because the dominate diffusion species in Cu-Al IMCs is copper. Results show that the existence of Pd restrained the growth rate of IMCs due to the formation of the Pd-enriched layer near the interface at the anode which acted as a diffusion barrier; however, a notch was formed at the cathode and the effect on the IMC growth rate could be neglected there. This may be the reason why Pd-coated copper wires show better bonding reliability than pure copper wires in the wire bonding process.
Schneebeli, Severin Thomas. "Computers for chemistry and chemistry for computers: From computational prediction of reaction selectivities to novel molecular wires for electrical devices." Thesis, 2011. https://doi.org/10.7916/D8V4125M.
Full textWei-HsiangHuang and 黃蔚翔. "The interfacial reaction of Ag-xPd wire bonding on Al pad under various testing conditions." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/10491905604810275587.
Full text國立成功大學
材料科學及工程學系
104
The industry is trying to replace part of gold and copper wire bond with silver wires. Ag-Pd alloy wire was reported as a potential candidate because of its high reliability. This study investigated the interfacial reaction of Ag-xPd wire bonding on Al pad under various testing conditions. Aging, pressure cook test (PCT), temperature cycling test (TCT) and un-biased accelerated and humidity stress test (u-HAST) were applied on As-bonded AgxPd(1~6%) wire bonding samples to study the interfacial reaction. The SEM images of wire bond under different test conditions were analyzed. The results indicated that the growth of the intermetallic compound (IMC) was enhanced when the content of Pd is more than 3.5%. The composition of IMC was analyzed by SEM-EDX. It shows that the contents of Al in IMC decrease when the Pd content of alloy wire increases. An increase in the content of Pd in alloy wire leads to promote the formation of (Ag,Pd)2Al rather than (Ag,Pd)3Al2. After PCT test, the corrosion behavior occurred at the interface and Ag-rich IMC (Ag,Pd)3Al formed above the Al-pad. Under TCT test, the (Ag,Pd)3Al2 formed at the interface. The (Ag,Pd)3Al2 exhibits larger difference the coefficient of thermal expansion (CTE) with alloy wire. It tends to induce the crack formation during TCT test. The increasing Pd content inhibits the corrosion of the wire bond under u-HAST test.
Lung, Chien-Hua, and 龍健華. "The Chemical Reaction for Potentially Fabrication the Atomic-Scale Metal Wire on the Semiconductor Surface Using a Metal String Complex as a Precursor." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/69100373909815514863.
Full text國立臺灣大學
化學研究所
89
The research focused on nanostructures, nanodevices and even on molecular devices has been extensively carried out due to their potential applications in fabrication of computer chips. Among them, the fabrication process of the nanowire has drawn great attention because of its use as the data-transfer line in the nano-scale. The ultimate goal is to fabricate the atomic-scale metal wire on the surface. The recent success in the synthesis of the linear metal-chain complexes with various nuclear chain lengths has stimulated us to study the chemical reaction between this kind of compounds and the semiconductor surface in order to obtain insights into the process which may govern the fabrication of the atomic-scale metal wire on surfaces. In this study, a tri-nuclear metal string complex Cr3(μ3-dpa)4Cl2 (dpa=dipyridylamido anion) is used as the precursor and deposited on GaN(0001) and Si(100) surface in a UHV environment. Their surface chemical reactions are monitored using temperature programmed desorption, Auger electron spectroscopy, synchrotron radiation core-level spectroscopy, and secondary ion mass spectroscopy. At low temperature, the layer of adsorbates might be formed through Cr bonding to the surface. At an exposure of 50L, there may be two adlayers on the GaN(0001) surface, the first one binding with a configuration similar to the molecular dish laying flat on the surface, the second one with the dish standing up. At increasing substrate temperatures, the complex decomposes in two different stages. One relates to the desorption of the dpa ligand from the adsorbed complex at ~340K, the other to a further decomposition of the residual complex at ~540K. A Cr metal adlayer, containing mainly Cr adatoms with a trace amount of Cr dimers, can be obtained when the metal-string complex is exposed to the GaN surface at high substrate temperature above 770K. In the case of Cr3(μ3-dpa)4Cl2 reaction on the Si(100) surface, the ligand on the complex decomposes upon adsorption on the surface. At increasing substrate temperature, further decomposition of the ligand will occur. At a higher exposure, the ligand molecule can desorb at a substrate temperature of 280K and the decomposed CrxLy molecule will desorb from the Si(100) surface at the temperature of 400K and 490K.
Müller, Wolfhart. "Temperaturverhältnisse und Reaktionskinetik beim Ziehen und Wärmebehandeln von Draht." Doctoral thesis, 1997. https://tubaf.qucosa.de/id/qucosa%3A22532.
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