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91.
H. L. Kwok 《Journal of Electronic Materials》2013,42(3):355-358
For decades, continuous attempts have been made to improve the figure of merit (ZT) of thermoelectrics. The theory behind the Seebeck effect itself is well researched, but the problem with ZT is related to materials properties that offset one another. This work analyzed the link between the site energy distributions and thermal conductivity of oxidized poly(3,4-ethylenedioxythiophene-tosylate) (PEDOT:Tos), which was reported to be a good organic thermoelectric. To understand how heat flow was affected by “disorder” in PEDOT:Tos and the associated electron–phonon interactions, we computed the values of the thermal conductivity κ and ZT using materials parameters extracted from the open literature. By varying the values of the parameters separately, we were able to identify their individual influence on κ and ZT. Our results suggest that ZT is most sensitive to changes in σ, the bandwidth of the density of states (DOS) of the transport sites, and less so to changes in n eff, the effective carrier density. Our simulations also suggested that ZT could become exceptionally large (approaching a value of ~20) if σ were lowered to 1 meV to 2 meV. This would be a tremendous approach to increase ZT in oxidized PEDOT:Tos. 相似文献
92.
93.
G. H. Yeoh R. K. K. Yuen D. H. Chen W. K. Kwok 《Numerical Heat Transfer, Part A: Applications》2013,63(1-2):153-172
Field modeling that incorporates increasingly complex representations of the physical and chemical processes for compartment fires warrants a detailed evaluation. Detailed quantitative comparisons of our predicted velocity and temperature fields against established the computed results of Lewis, Moss, and Rubini and the experimental data of Steckler, Quintiere, and Rinkinen of a single compartment fire are in good agreement. The prospect of using a flamelet-based combustion model is encouraging. Here, more detailed chemistry can be incorporated, especially that used to predict toxic CO concentrations. This, together with the discrete ordinates radiation method, offers potential in building fire prediction. 相似文献
94.
Charge Transport: Nonfullerene Electron Transporting Material Based on Naphthalene Diimide Small Molecule for Highly Stable Perovskite Solar Cells with Efficiency Exceeding 20% (Adv. Funct. Mater. 20/2018) 下载免费PDF全文
95.
Posttranslational acetylation of proteins regulates many diverse functions, including DNA recognition, protein-protein interaction, and protein stability. The identification of enzymes that regulate protein acetylation has revealed broader use of this modification than was previously suspected. In this study, we describe a method for identifying protein acetylation at lysine residues by analysis of digested protein using HPLC/ESI-MS with a new modification-specific marker ion. Collision-induced dissociation with capillary or nano-LC/ESI-TOF-MS was used to obtain a fragment ion useful as a marker for acetylated lysine. Although the acetylated lysine immonium ion at m/z 143.1 has been used as a marker ion for detecting acetylated lysine, it can be confused with internal fragment ion in some peptides, producing false positive results. We have found a novel marker ion at m/z 126.1, which is a further fragment ion induced by the loss of NH3 from the acetylated lysine immonium ions at m/z 143.1. This novel marker ion was found to be more specific and approximately 9 times more sensitive than the immonium ion at m/z 143.1. In addition, no interfering ions for acetylated peptides were found in the extracted ion chromatogram at m/z 126.1. The utility of this method was demonstrated with acetylated cytochrome c as a model compound. After the modification was probed by the new marker ion, the acetylated lysine site was determined by the CID-MS spectrum. This method was applied to identify histone H4 acetylation in HeLa cells treated with trichostatin A. Three protein bands separated by acid-urea-Triton gel electrophoresis were confirmed as tetra, tri, and diacetylated histone H4 at lysines 5, 8, 12, and 16. This method may be useful for assaying for lysine acetylation, which is an important regulatory process for a range of biological functions. 相似文献
96.
A method of designing polarization rotators with double-liquid-crystal (LC) cells is presented. When placed between a polarizer and an analyzer, the polarization rotator becomes a polarizing color filter. Any required color can be generated by optimization of the parameters of the double-LC layers. One specific example of a green filter is given. This filter is analyzed in terms of the optical performance, including transmission spectrum, color coordinates, and viewing angle. A sample green polarizing color filter was made and compared with the theoretical results. 相似文献
97.
E. P. Pozhidaev V. G. Chigrinov Yu. P. Bobilev V. M. Shoshin A. A. Zhukov A. L. Andreev I. N. Kompanets Li Xihua E. E. Gukasjan P. S. Komarov O. A. Shadura H. S. Kwok 《Journal of the Society for Information Display》2006,14(7):633-641
Abstract— A passively addressed 64 × 64 ferroelectric liquid‐crystal display (FLCD) has been developed. The display matrix has a 33 × 33 mm2 aperture, and the FLC layer thickness is 5.2 ± 0.2 μm. The display device operates with a frame frequency of 30 Hz (at Vrow = ±18 V, Vcol = ±9 V, T = 23°C), generating a continuous gray scale which can be memorized for more than 10 days after the driving voltage is switched off. A new approach for multiplex electronic addressing of the FLCD gray scale is proposed. The conditions of the hysteresis‐free gray‐scale generation for multiplex addressing and the gray‐scale memorization after the voltage is switched off, as well as the time steadiness of memorized images, are considered. 相似文献
98.
Moon Gi Cho Kyung Wook Paik Hyuck Mo Lee Seong Woon Booh Tae-Gyu Kim 《Journal of Electronic Materials》2006,35(1):35-40
The interfacial reaction between 42Sn-58Bi solder (in wt.% unless specified otherwise) and electroless Ni-P/immersion Au was
investigated before and after thermal aging, with a focus on the formation and growth of an intermetallic compound layer,
consumption of under bump metallurgy (UBM), and bump shear strength. The immersion Au layer with thicknesses of 0 μm (bare
Ni), 0.1 μm, and 1 μm was plated on a 5-μm-thick layer of electroless Ni-P (with 14–15 at.% P). The 42Sn-58Bi solder balls
were then fabricated on three different UBM structures by using screen printing and pre-reflow. A Ni3Sn4 layer formed at the joint interface after the pre-reflow for all three UBM structures. On aging at 125°C, a quaternary phase,
identified as Sn77Ni15Bi6Au2, was observed above the Ni3Sn4 layer in the UBM structures that contain Au. The thick Sn77Ni15Bi6Au2 layer degraded the integrity of the solder joint, and the shear strength of the solder bump was about 40% less than the nonaged
joints. 相似文献
99.
The implementation of a particle filter (PF) for vision-based bearing-only simultaneous localization and mapping (SLAM) of a mobile robot in an unstructured indoor environment is presented in this paper. Variations, using techniques from the genetic algorithm (GA), to standard PF procedures are proposed to alleviate the sample impoverishment problem. A monochrome CCD camera mounted on the robot is used as the measuring device and a measure on the image quality is incorporated into data association and PF update. Since the bearing-only measurement does not contain range information, we add a pseudo range to the measurement during landmark initialization as a hypothesised pair and the non-promising landmark is removed by a map management strategy. Simulation and experimental results from an implementation using real-life data acquired from a Pioneer robot are included to demonstrate the effectiveness of our approach. 相似文献
100.
JP Dubey KR Dorough MC Jenkins S Liddell CA Speer OC Kwok SK Shen 《Canadian Metallurgical Quarterly》1998,28(8):1293-1304
Clinical signs, diagnosis, treatment and isolation of Neospora caninum from two littermate dogs are described. Three of six pups from a Labrador bitch developed paralysis. Neosporosis was diagnosed ante mortem by serological examination in two of the affected pups. At necropsy, tissue cysts were seen in unstained smears and in histologic sections of their brains. Tissue cysts were often thin-walled (approximately 1 micron) but antigenically and ultrastructurally identified as N. caninum. Furthermore, N. caninum (isolates NC-4, NC-5) was isolated in mice and in cell cultures inoculated with neural tissues of these two dogs. Serological diagnosis of neosporosis using a variety of tests is discussed. 相似文献