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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.
121

Smoother Substrate Deposition Designs and Process Emulations of DC Magnetron Sputters

Chang, Chih-Wen 17 August 2012 (has links)
To smooth the substrate depositions of DC magnetron sputter (MS), such that the supplementary electrical and mechanical adjustment efforts can be alleviated, a refinement scheme that can be applied directly to the existing DC MS will be introduced. By properly controlling the magnetic and electric fields inside the vacuum chamber, trajectories of those atoms that are sputtered from the target surface can be more spread out. In addition, with the resultant higher plasma density, chance of collisions among the sputtered atoms and those Ar ions in the plasma will also be increased, hence the resulting distributions of target atoms deposited on the substrate surface will certainly be evened out. To further confirm such concepts, a rational emulating process that can explore both the atom sputtering process from the target and those collisions at the chamber with different three-dimensional magnetic and electric field environments is also developed. Thus the associated performance investigations on the DC MS with different magnetron arrangements can then be conveniently carried out.
122

Courtship acoustics and mating in Cotesia, a genus of parasitoid wasps

Joyce, Andrea Lee 15 May 2009 (has links)
Cotesia are parasitoid wasps (Hymenoptera: Braconidae) that are used for biological control of pest moths (Lepidoptera: Noctuidae, Pyralidae) that damage agricultural crops. This dissertation investigated courtship acoustics and mating, and their relevance to biological control, in members of the Cotesia flavipes species complex, and a noncomplex member, Cotesia marginiventris. The first study investigated whether courtship acoustics were species specific for two members of the Cotesia flavipes complex, C. flavipes and C. sesamiae, and for C. marginiventris. During courtship, male Cotesia fan their wings and produce low amplitude sounds and substrate vibrations. The airborne and substrate components of courtship were similar within a species. However, the courtship acoustics of each species was distinct. The duration and frequency of several courtship acoustic components distinguished each species, while some components did not differ among species. The second study investigated mating success and transmission of courtship vibrations on natural and artificial rearing substrates for Cotesia marginiventris. Mating success was measured on plastic, glass, corn and bean leaves, and chiffon fabric. Mating success was lowest on plastic and glass, intermediate on corn and bean leaves, and highest on chiffon. Substrate influenced transmission of courtship vibrations. Durations of courtship vibrations were longer on corn, bean and chiffon than on plastic. Frequency modulation occurred on corn, bean and chiffon, and amplitude was greatest on chiffon. The mating success of normal and dealated males was higher on chiffon than on glass, suggesting that courtship communication relied in part on substrate vibrations. The third study examined female and male mate choice in a solitary and a gregarious species, C. marginiventris and C. flavipes, respectively. Females of the solitary species, C. marginiventris, mated more frequently with large than small males, and this did not appear to be the result of male competition. Male choice for female size was not apparent in C. marginiventris. Females of the gregarious parasitoid, C. flavipes, mated with large or small males with similar frequencies, and male-male competition was not observed. In the male choice experiment, C. flavipes males attempted copulation and mated more with smaller females, and smaller females accepted males more than large females.
123

Establishment of Model Library for Inductors and Capacitors in Multilayer Substrate Structure

Ma, Hui-Lin 05 July 2004 (has links)
In this thesis, a standard flow path is proposed to establish the model library for inductors and capacitors in multilayer substrate structure. By the way of excellent agreement between simulation and measurement within self resonant frequency ¡]SRF¡^, we aimed at the demanded performance of passives in modules and adopted Pi-section equivalent circuits as basic model. Meanwhile, an automatic program on CAD-based platform is used for extraction of Pi-model circuit elements and calculation of SRF, quality ¡]Q¡^factor and modeling errors. In the end, we contributed the methodology to have the best performance of embedded passives design in multilayer substrate structure and established a completed model library for inductors and capacitors embedded in low temperature co-fired ceramic¡]LTCC¡^substrate for the design need in implementation of RF modules.
124

Study of cutting quality for TFT-LCD glass substrate

Liu, Chi-sheng 24 August 2006 (has links)
This study is the method of using the mechanical type to cut the substrate of the glass , under the circumstances that the glass surface is cut directly, probably produced 10¡ã20% of the depth of crack that is the thickness of glass, and then pulled the glass and split by mechanical stress , use the ANSYS and finite element method carry on relevant research and compare, survey the perfect cutting parameter to increase the yield in the future. This study is in order to find out the surface fracture stress distribution status after cutting and take advantage with the finite element method ,and compare with the result of median crack when glass substrate after cutting .It discuss with change parameter of the cutting pressure and Cutting depth ,than to compare with finite element method, it regard as discussing the quality after cutting to reduce the risk of surface defect.
125

The molecular dynamics investigation into the adsorption behaviour of water nanocluster on a solid substrate

Huang, Jian-yuan 07 September 2006 (has links)
In this paper, molecular dynamics is used to investigate into the adsorption behaviour of water nanocluster on a solid substrate. The potential function of water molecule is F3C (Flexible three-Centered)model. Water nanocluster with radius of 5Ǻ, 7Ǻ and 10Ǻ were studied. Five adsorption parameters between water molecules and the substrate were used to represent the hydrophilic magnitude. The influences of different size and interaction on adsorption behaviour were investigated. The simulation results indicate that when the hydrophilic magnitude is increasing, the water molecule number of adsorption on solid substrate increases, the water nanocluster tends to spread flatly on the substrate, and the contact angle was very close to zero, which represents better wettability. The larger water nanocluster distribute widely upon a substrate.
126

Warpage Study of Film-BGA

Chen, Wen-Bin 21 June 2001 (has links)
ABSTRACT Wireless communication products require thinner and small packaging to allow for reductions in Cell Phone and PDA product sizes. Currently, the Film-BGA (Ball Grid Array) package is in production for thinner and small case. The Film-BGA package is a thin package that uses polyimide tape as a substrate to reduce the overall package profile to 1 mm and ball pitch is 0.5 mm. The Film substrate can reach 0.11 mm thick or less. Analysis the Film-BGA model consists of a sequentially coupled thermal- mechanical analysis considering epoxy curing, post molding compound and IR-Reflow by MARC. After these processes Film-BGA will occur warpage and residual stress, we will study the sizes of materials on the warpage and residual stress by Taguchi Method. From the MARC analysis, it is found that due to the coefficient of thermal expansion (CTE) mismatch between solder ball, die, molding compound, epoxy and substrate, there exists very high stress near the interfaces of epoxy and results the maximum warpage (y-displacement) that occurs at the edge of the substrate after IR-Reflow. By means of the Taguchi Method, it is found that die size greatly affect the warpage of Film-BGA more than epoxy size and molding compound size. It is also found that epoxy size has more effect than die size and molding compound size on the residual stress of Film-BGA.
127

Thermal Fatigue Life Study for Film-BGA

Chen, Wang-Lung 20 June 2002 (has links)
This study aims to investigate the effect of a 96 I/O Film-BGA package of surface mounted components on the thermal induced nonlinear viscoplastic deformation of solder balls during temperature cyclic loading between -40¢J to 125¢J. Specifically, it aims to study the trend effect of the joint fatigue life with respect to four control factors of the PI (Polyimide) thickness, die size, die thickness, and the upper copper trace thickness. Then, two different package types of Fan-in and Fan-out design in terms of the joint fatigue life are discussed. Due to the structure/loading symmetry, a three-dimension octant finite element structure was modeled to capture the entire package structural behaviors and a formulation of Modified Coffin-Manson was used to predict the joint fatigue life. Under temperature cyclic loading, the study results show that the die size, die thickness, and PI thickness had significant impact on the solder joint fatigue life, especially the effect of applying die size to the joint, but the upper copper trace thickness had little effect on the joint fatigue life. The study results also show that the package type of Fan-out design had higher joint fatigue life than that the package type of Fan-in design did for this Film-BGA package. In addition, by using the Taguchi method, the research could find the intensity of affected fatigue life due to the selected four control factors, and determine the optimized design by means of the optimized dimensions of the control factors. Then, the use of the ANOVA (analysis of variance) method helped the researcher predict the optimized joint fatigue life in comparison with the study results by using ANSYS finite element software analysis.
128

Enzyme mechanism, substrate specificity, and lipoprotein association of human plasma platelet-activating factor acetylhydrolase /

Min, Jung-Hyun, January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 113-118).
129

The effects of prolonged sitting and acute exercise on postprandial plasma triglyceride concentration

Kim, Il-Young, 1973- 31 January 2012 (has links)
These studies investigated the effect of physical inactivity (prolonged sitting) and physical activity (walking, standing, and moderate intensity exercise) on postprandial plasma triglyceride concentration (PPTG). In the first study, we evaluated the effect of low intensity intermittent walking at ~25% VO₂max (WALK) and energy-matched moderate intensity running at ~65% VO₂max (RUN) on PPTG, compared to a sitting control (SIT). RUN reduced incremental area under the curves for plasma triglyceride concentration (TG AUC[subscript I]), compared to WALK by 17.3% (p = 0.04) and SIT by 27% (p [less than] 0.001). The reduced TG AUC[subscript I] in RUN was accompanied by enhanced whole body insulin sensitivity, compared to WALK and SIT (for both, p [less than] 0.05). Whole body postprandial fat oxidation at rest following a high fat test meal intake was enhanced in RUN by 31% (P [less than] 0.001) and to a lesser extent in WALK by 8.4% (p [less than] 0.005), compared to SIT. In the second study, we evaluated 1) the effect of 2 days of prolonged sitting on PPTG, and 2) the effect of 4 days of SIT on the ability of an acute bout of exercise to reduce PPTG, compared to the same days of active walking and standing with calorically balanced diet (WALK+B). To distinguish the effect of prolonged sitting from the excess calorie effect, we had a sitting condition with calorically balanced diet (SIT+B) in addition to a sitting condition with hypercaloric diet (SIT+H). Following 2 days of respective food and activity control, WALK+B was lower in TG AUC[subscript T] by 21.3% and AUC[subscript I] by 17.4%, compared to SIT+H (for both, p [less than] 0.005). WALK+B was lower than SIT+B for TG AUC[subscript T] by 17.7% (p = 0.165) and AUC[subscript I] by 23.5% (p = 0.145) although statistical significance was not achieved. Remarkably, an acute exercise following 4 days of either SIT+H or SIT+B failed to reduce both TG AUC[subscript T] and AUC[subscript I], compared to SIT+B in HFTT1. The same exercise following 4 days of WALK+B, however, reduced both TG AUC[subscript T] by 29% and TG AUC[subscript I] by 32% in HFTT2, compared to SIT+B in HFTT1 (for both, p [less than] 0.02). Further, both SIT conditions reduced relative whole body fat oxidation in favor of increases in carbohydrate oxidation, compared to WALK+B by more than 40% in both HFTT1 and HFTT2. Taken together, our data suggest that 1) exercise intensity plays an independent role with higher intensity being more effective than lower intensity exercise in reducing PPTG, and 2) prolonged sitting with excess energy intake amplifies PPTG and prolonged sitting impairs the ability of an acute bout of moderate intensity exercise to reduce PPTG. This emphasizes the importance of regular participation in moderate-to-vigorous intensity exercise and reducing sitting time by increasing non-exercise physical activities (i.e., walking and standing) for the favorable postprandial metabolic health from the individual and public health perspectives. / text
130

Characterization of Substrate Uptake by Avian Skeletal Muscle

Sweazea, Karen Leanna January 2005 (has links)
The goal of this work was to characterize avian skeletal muscle (SKM) glucose and fatty acid uptake. English sparrows (Passer domesticus) were used for the following studies: 1. Characterization of glucose uptake, 2. Identification and localization of glucose transporters, 3. Characterization of free fatty acid uptake, and 4. Reciprocal inhibition of glucose and free fatty acids. The results are summarized as follows. Isolated SKM incubated for 60 minutes with insulin, IGF-1, caffeine or AICAR demonstrated no increase in glucose transport. Interestingly, uptake was decreased in the presence of incremental unlabeled glucose suggesting the presence of glucose transporters (GLUT) and by phloretin, an inhibitor of transport proteins, decreased transport. The SKM glycogen content was low, which is supportive of the observed minimal glucose uptake. These findings suggest that GLUT expression may differ in birds as compared to mammals. GLUT1 and GLUT3 gene expression, but not GLUT4, were found in all tissues examined and share a high degree of homology with published chicken sequences. In addition, GLUT3 and GLUT4 proteins were not detected, whereas GLUT1 protein was abundant in blood-tissue barriers. Sparrows have high plasma ketone body levels suggestive of a high rate of free fatty acid (FFA) oxidation. In vitro uptake of radiolabeled oleic acid (OA) was maximal at 60 minutes and competitively inhibited by unlabeled OA suggesting a facilitative process. Radiolabeled OA uptake was not increased by IGF-1, caffeine and AICAR, whereas insulin increased uptake at 60 minutes. Inhibitors of protein-mediated substrate transport increased OA uptake by 60 minutes (DIDS and phloretin) whereas a specific inhibitor of long chain FFA transport, sulfo-N-succinimidyl oleate, decreased its uptake at 2.5 min. In reciprocal inhibition studies, 20mM unlabeled glucose and OA inhibited the uptake of their radiolabeled counterparts. Glucose (20mM) significantly decreased labeled OA uptake 36% and 20mM OA significantly decreased labeled glucose transport by 49%. These data begin to elucidate why avian skeletal muscle may not take up glucose to an appreciable extent and further, why avian skeletal muscle is insulin resistant.

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