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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

none

Chang, Che-lang 12 July 2000 (has links)
PCB (Printed Circuit Board) industry is an important industry in Taiwan. It is the base of most electronic products. In 1999¡Athe productive value of PCB is over NT¢C110 billion and Taiwan is the big three in the world in producing PCB. PCB is so important for Taiwan economic that we will research it by S-C-P (Structure-Conduct-Performance).
2

The Effect of PCB 47 and PCB 77 on the Female Reproductive System: Gestational Versus Lactational Effects in Rats

Wang, Zhi 29 November 2011 (has links)
No description available.
3

Erfassung der PCB-Belastung in Gewässern unter Anwendung eines biologischen Monitoring-Programmes /

Mast, Paul-Gerhard. January 1993 (has links)
Zugl.: Berlin, Techn. Universiẗat, Diss., 1993.
4

Cell controller for printed circuit board assembly rework

Chan, Ching-Yuen January 1994 (has links)
No description available.
5

High speed signal compensation on printed circuit boards

Boos, Bernie 11 February 2004
Data transfer rates on printed circuit boards are quickly approaching speeds that challenge the limits of todays technology. Inter-chip communication has increased dramatically. Currently data rates have reached 3.125 Gb/s on standard circuit board, but chip-to-chip digital communication has currently reached a plateau and several problems need to be addressed to significantly increase data transfer rates. Inductive and capacitive components of far end crosstalk (FEXT) conveniently cancel each other as they propagate on an interconnect transmission line, however the inductive and capacitive components of near end crosstalk(NEXT) add together and interfere with signals on adjacent receivers.<p>This paper proposes a novel solution for canceling crosstalk by adding extra circuitry to the receiver within the integrated circuit. This digital circuit delivers one of three appropriate levels of crosstalk compensation to the incoming signal. Since the circuit is digital, simple blocks can be used to implement it on a complimentary metal-oxide semiconductor (CMOS) integrated circuit and consume very little extra silicon.<p>This paper presents the compensation circuit and reports the results of the simulations, which demonstrate improved performance over the standard system. The compensation circuit is specifically aimed at adjacent input and output lines on a microchip. Simulations of a typical circuit board configuration operation have shown crosstalk that is only 15 dB lower than a received attenuated signal. The crosstalk cancellation circuit has been shown to improve this by as much as 10 dB.
6

High speed signal compensation on printed circuit boards

Boos, Bernie 11 February 2004 (has links)
Data transfer rates on printed circuit boards are quickly approaching speeds that challenge the limits of todays technology. Inter-chip communication has increased dramatically. Currently data rates have reached 3.125 Gb/s on standard circuit board, but chip-to-chip digital communication has currently reached a plateau and several problems need to be addressed to significantly increase data transfer rates. Inductive and capacitive components of far end crosstalk (FEXT) conveniently cancel each other as they propagate on an interconnect transmission line, however the inductive and capacitive components of near end crosstalk(NEXT) add together and interfere with signals on adjacent receivers.<p>This paper proposes a novel solution for canceling crosstalk by adding extra circuitry to the receiver within the integrated circuit. This digital circuit delivers one of three appropriate levels of crosstalk compensation to the incoming signal. Since the circuit is digital, simple blocks can be used to implement it on a complimentary metal-oxide semiconductor (CMOS) integrated circuit and consume very little extra silicon.<p>This paper presents the compensation circuit and reports the results of the simulations, which demonstrate improved performance over the standard system. The compensation circuit is specifically aimed at adjacent input and output lines on a microchip. Simulations of a typical circuit board configuration operation have shown crosstalk that is only 15 dB lower than a received attenuated signal. The crosstalk cancellation circuit has been shown to improve this by as much as 10 dB.
7

Data Bus Deskewing Systems in Digital CMOS Technology

Atrash, Amer Hani 13 May 2004 (has links)
This dissertation presents a study of signal deskewing systems in standard CMOS technologies. The objective of this work is to understand the limitations of deskewing systems as they are applied to modern systems and present new architectures to overcome past limitations. Traditional methods for signal deskewing are explored and the general limitations of these methods are identified. Several new architectures are proposed to address the limitations of previous techniques. The systems will be investigated with regard to minimum resolution, programming time, delay, maximum data rate, full scale range, and duty cycle distortion. Several other effects that are critical to the operation of deskewing systems will also be investigated. These effects include overshoot caused by parasitic package inductance, the impact of capacitive terminations, and the effect of mutual inductance between traces. To fulfill the requirements of this study, two deskewing systems are implemented in a 0.25um process. An open-loop system for deskewing wide data busses and a closed-loop system for deskewing a differential pair of lines are both fabricated. Both systems are found to meet the expected performance metrics, providing validation of the proposed techniques. Use of the proposed architectures allows the limitations of previous methods to be overcome. The remaining work is validated through either analytical techniques, simulations, or both where appropriate.
8

Study on the DLC Film Deposition Microdrill by ECR-CVD

Lie, Sim-hong 05 July 2004 (has links)
A hybrid physical vapor deposition- electron cyclotron resonance-chemical vapor deposition (PVD-ECRCVD) coating system HBS900 is used to deposit the diamond-like carbon (DLC) film on the microdrills. It could keep friction low results in improving the productivity of the drill holes on the printed circuit board (PCB). In order to improve the adhesion strength of the DLC films,functionally gradient Ti/TiN/TiCN supporting multilayer were pre-deposited initially on the microdrills. The hard coatings of titanium nitride (TiN) and titanium carbonitride (TiCN) as multilayer are deposited by PVD with high rate coating sources based on the principle of electrical arc vaporization and magnetron sputtering process. The on it following dry lubricant coating is composed of amorphous, diamond like carbon (DLC) deposited by ECRCVD plasma in the same recipient. The structural characteristics of DLC films were investigated by Raman spectroscopy and standard scratch and pin-on-disk test.The properties of DLC films coating on the microdrills are obtained and summarized as follows: excellent adhesion 65N, and coefficients of friction less than 0.15. After micro-hole drilling, we obtained the high quality drilled hole from the inspection of roughness and nailheading. As a result of adapting a microdrill coated with DLC film, the drilling lifetime was significantly improved to reach about 2.5 times than that of the uncoated one.
9

Trace analysis of dioxins and dioxin-like PCBs using comprehensive two-dimensional gas chromatography with electron capture detection /

Danielsson, Conny, January 2007 (has links)
Diss. (sammanfattning) Umeå : Umeå universitet, 2007. / Härtill 6 uppsatser.
10

Análise dos parâmetros que interferem no metabolismo da microbiota anaeróbia e anóxica na remoção de bifenilas policloradas / Analysis of the parameters that affect the metabolism of microorganisms in the anaerobic and anoxic removing polychlorinated biphenyls

Silva, Mara Rúbia de Lima e 24 September 2015 (has links)
A elevada concentração de cloro das bifenilas policloradas provoca alta toxicidade do composto, o qual dificulta sua biodegradação. A contaminação de PCB no Brasil foi confirmada em estudo realizado na Bahia de Santos-São Vicente (São Paulo), o qual revelou a necessidade de um plano de ação para o controle e remoção de PCB no Brasil. Pretendeu-se assim, na realização da presente pesquisa, verificar quatro hipóteses: (1) A técnica de Microextração em fase sólida é uma metodologia eficaz para avaliação de bifenilas policloradas de amostras de reatores; (2) A condição fermentativa-metanogênica abriga comunidade resistente ao PCB, e removê-lo; (3) A condição desnitrificante abriga comunidade resistente ao PCB, e removê-lo e (4) A remoção de PCB, bem como, a composição microbiana é distinta em cada condição metabólica. Para tanto, reatores em batelada foram montados separadamente com biomassa anaeróbia proveniente de reator UASB usado no tratamento de água residuária de avicultura e biomassa de sistemas de lodos ativados de tratamento de esgoto sanitário. Os reatores operados em condição mesófila foram alimentados com meio sintético, co-substratos, sendo etanol (457 mg.L-1) e formiato de sódio (680 mg.L-1) para os reatores anaeróbios, e somente etanol (598 mg.L-1) para os reatores anóxicos, além de PCB padrão Sigma (congêneres PCBs 10, 28, 52, 153, 138 e 180) em diferentes concentrações, dependendo do objetivo do ensaio. A aplicação do método de extração por SPME com análise em cromatógrafo gasoso com detector por captura de elétrons foi adequada para a determinação dos seis congêneres de PCB. Obteve-se ampla faixa de linearidade, seletividade frente aos vários interferentes, além da robustez do método, utilidade e confiabilidade na identificação e quantificação específica dos seis congêneres de PCB. A Hipótese 1 foi aceita; ou seja, por meio da aplicação da metodologia SPME foi possível quantificar os PCB nos reatores em batelada. Apesar de ter sido comprovada a inibição metanogênica na presença de PCB, com IC50 de 0,03 mg.L<sup-1 (concentração na qual 50&#37; da atividade metanogênica é inibida), a partir da análise dos reatores metanogênicos no Ensaio de Remoção, foi confirmada a remoção de 0,92 mg.L-1, 0,19 mg.L-1, 0,18 mg.L-1, 0,07 mg.L-1, 0,55 mg.L-1 e 0,47 mg.L-1 para os PCBs 10, 28, 52, 153, 138 e 180, respectivamente, para 1,5 mg.L-1 inicial. Thermotogaceae, Sedimentibacter, Anaerolinaceae e Pseudomonas, foram identificadas nos reatores anaeróbios por meio da plataforma Illumina. Representantes de Thermotogaceae e Sedimentibacter foram identificados em sistemas com elevada taxa de remoção de PCB, e representantes do filo Chloroflexi (grupo no qual representantes da Anaerolineae estão inseridos) foram os primeiros microrganismos desalogenadores de PCB identificados. Assim a Hipótese 2 foi aceita; ou seja, por meio de ensaios em batelada foi comprovada a toxicidade do PCB sobre a comunidade anaeróbia, a alteração da composição microbiana influenciada pela presença de PCB e a remoção nesta condição. Verificou-se ainda que na presença de PCB ocorreu a desnitrificação e comparando-se diferentes relações C/N-NO3-, foi estipulado a relação 6,95 como ideal na presença de PCB. Mesmo sendo confirmada a inibição da comunidade anóxica na presença de PCB com IC50 de 1,0 mg.L-1, verificou-se remoção de 1,02 mg.L-1, 0,85 mg.L-1, 1,31 mg.L-1, 1,02 mg.L-1, 0,03 mg.L-1, e 0,09 mg.L-1, para os PCBs 10, 28, 52, 153, 138 e 180, respectivamente, para 1,5 mg.L-1, inicial. Bactérias semelhantes a Aeromonadaceae, Lutispora, Sedimentibacter e Thermotogaceae foram identificadas nos reatores desnitrificantes. Representantes de Aeromonadaceae e Lutispora estão relacionados com o metabolismo desnitrificante e representantes de Thermotogaceae e Sedimentibacter foram identificados em sistemas com elevada taxa de remoção de PCB. A Hipótese 3 foi também aceita; ou seja, por meio de ensaios em batelada foi calculada a relação C/N-NO3- ideal na presença de PCB e foi comprovada a toxicidade do PCB sobre a comunidade anóxica, a alteração da composição microbiana influenciada pela presença de PCB e a remoção nesta condição. A maior remoção de PCB foi verificada para a condição anaeróbia (entre 45&#37; a 100&#37;), quando comparada com a condição anóxica (entre 10&#37; a 95&#37;). Bactérias semelhantes a Sedimentibacter e pertencentes a família Thermotogaceae foram identificadas nas duas condições nutricionais. Entretanto, mesmo verificando-se elevada abundancia relativa desses grupos nos reatores, evidenciou-se distinção entre as biomassas em cada condição. Assim, a Hipótese 4 foi aceita; ou seja, por meio de ensaios em batelada foi comprovada maior eficiência de remoção sob condição anaeróbia e distinta composição microbiana em cada condição. / The high chlorine concentration in polychlorinated biphenyls improves its toxicity, complicating their biodegradation. A study conducted in Santos-São Vicente Bay (São Paulo) confirmed the PCB contamination in Brazil and reveled the need of an action plan to control e remove the PCB in Brazil. In this sense the aim of this study was to evaluate four hypotheses: (1) The Solid Phase Micro Extraction is an efficient methodology to evaluate biphenyl polychlorinated in reactors; (2) The fermentative-methanogenic microorganisms are resistant to PCB and capable to consume it; (3) The denitrifying microorganisms are resilient to the PCB and capable to remove it; (4) The PCB removal, as well the microbial composition is distinct in each condition. Therefore, batch reactors were operated separately inoculated with anaerobic biomass from UASB reactor treating poultry wastewater and biomass from activated sludge treating sewage wastewater. The reactors were feed with synthetic medium, co-substrates, as ethanol (457 mg.L-1) and sodium formate (680 mg.L-1) for the anaerobic reactors, and ethanol (598 mg.L-1) for the anoxic reactors and different concentrations of six congeners of PCB (PCBs 10, 28, 52, 153, 138 and 180) depending on the aim of the assay. The applicability of SPME technique in gas chromatography with electrons capture detection was attested in the analysis of six PCB congeners. Higher linearity, selectivity, accuracy, reproducibility and robustness was obtained in the PCB quantification analyses. The Hypothesis 1 was accepted; since the PCB congeners in the reactors were quantified by the SPME methodology. Although the PCB causes methanogenic inhibition, with IC50 of 0.03 mg.L-1 (concentration in which 50&#37; of the methanogenic metabolism is inhibited), by the Removal Assay was confirmed the anaerobic removal of 0.92 mg.L-1, 0.19 mg.L-1, 0.18 mg.L-1, 0.07 mg.L-1, 0.55 mg.L-1 and 0.47 mg.L-1 to PCB 10, 28, 52, 153, 138 and 180, respectively, for 1.5 mg.L-1 initial. By means of platform Illumina Thermotogaceae, Sedimentibacter, Anaerolinaceae and Pseudomonas, were identified in the anaerobic reactors. The Thermotogaceaeand Sedimentibacter were related to systems with high PCB removal and the Chloroflexi members (Anaerolineae phylum) were the first PCB-dechlorination microorganisms identified. Therefore, the Hypothesis 2 was accepted since the PCB leads to anaerobic inhibition and in the reactors were verified the PCB removal and changes in the microbial composition. Even with PCB, the denitrification metabolism occurs and evaluating different C/N-NO3- relations, the 6.95 was stipulated the ideal in the presence of PCB. Even though the PCB causes inhibition in the denitrification bacteria, with IC50 of 1.0 mg.L-1, by the Removal Assay in the denitrifying reactors, was confirmed the anoxic removal 1.02 mg.L-1, 0.85 mg.L-1, 1.31 mg.L-1, 1.02 mg.L-1, 0.03 mg.L-1 and 0.09 mg.L-1 to PCB 10, 28, 52, 153, 138 and 180, respectively, for 1.5 mg.L-1 initial. Aeromonadaceae, Lutispora, Sedimentibacter and Thermotogaceae were identified in the denitrifying reactors. Members of Aeromonadaceae e Lutispora were related to the denitrification metabolism and Thermotogaceae e Sedimentibacter were identified in systems with high PCB removal rate. The Hypothesis 3 was accepted since the PCB leads to anoxic inhibition and in the reactors were verified the PCB removal and changes in the microbial composition. The anaerobic reactors presented the higher PCB removal percentage (between 45&#37; and 100&#37;) when compared to the anoxic reactors (between 10&#37; and 95&#37;). Member of Sedimentibacter and Thermotogaceae were identifyied in both conditions. However, even with high relative abundance of these two groups in the reactors, it was shown distinct composition in each biomass. Thus, the Hypothesis 4 was accepted since the PCB removal was more efficient in the anaerobic condition and were verified different changes in the microbial composition in each condition.

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