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991.
992.
Cho E Kim B Choi S Han J Jin J Han J Lim J Heo Y Kim S Sung GY Kang S 《Journal of nanoscience and nanotechnology》2011,11(1):417-421
This paper introduces technology to fabricate a guided mode resonance filter biochip using injection molding. Of the various nanofabrication processes that exist, injection molding is the most suitable for the mass production of polymer nanostructures. Fabrication of a nanograting pattern for guided mode resonance filters by injection molding requires a durable metal stamp, because of the high injection temperature and pressure. Careful consideration of the optimized process parameters is also required to achieve uniform sub-wavelength gratings with high fidelity. In this study, a metallic nanostructure pattern to be used as the stamp for the injection molding process was fabricated using electron beam lithography, a UV nanoimprinting process, and an electroforming process. A one-dimensional nanograting substrate was replicated by injection molding, during which the process parameters were controlled. To evaluate the geometric quality of the injection molded nanograting patterns, the surface profile of the fabricated nanograting for different processing conditions was analyzed using an atomic force microscope and a scanning electron microscope. Finally, to demonstrate the feasibility of the proposed process for fabricating guided mode resonance filter biochips, a high-refractive-index material was deposited on the polymer nanograting and its guided mode resonance characteristics were analyzed. 相似文献
993.
Eugene Wai Keong Koh Cheng Hsin Chiu Yao Kun Lim Yong-Wei Zhang Hui Pan 《International Journal of Hydrogen Energy》2012
We investigate the hydrogen adsorption on and diffusion through the MoS2 monolayer based on density-functional theory. We show that the hydrogen atom prefers to bond to the S atom at the monolayer, leading to enhanced conductivity. The hydrogen atom can also adsorb at the middle of the hexagon ring by overcoming an energy barrier of 0.57 eV at a strain of 8%. Also, we show that the MoS2 monolayer is flexible and any mechanical deformation of the monolayer is reversible because the extension of the Mo–S bond is much smaller than the applied strain. The monolayer can block the diffusion of hydrogen molecule from one side to the other due to a high energy barrier (6.56 eV). However, the barrier can be reduced to 1.38 eV at a strain of 30% and even totally removed by creating S vacancies and applying a strain of 15%. The MoS2 monolayer may find applications in sensors to detect hydrogen, and as mechanical valve to control the concentration of hydrogen gas. 相似文献
994.
Seung Jin Oh Yoon Joon Lee Kuan Chen Young Min Kim Sang Hoon Lim Wongee Chun 《国际能源研究杂志》2012,36(2):249-258
An embedded two‐axis solar tracking system using Laboratory Virtual Instrumentation Engineering Workbench to write the operation and control algorithms was developed for enhancing solar energy utilization. The system consists of a real‐time processor, two motion‐control modules, two step drives, two step motors, feedback devices, and other accessories needed for functional stability. The real‐time processor allows the solar tracker to be used as a stand‐alone, real‐time system that can operate automatically without any external control. The system combines two different solar tracking methods: the optical method and the astronomical method. Cadmium Sulfide (CdS) sensors are employed to continuously generate feedback signals to the controller, ensuring high‐precision solar tracking even under adverse conditions. The CdS sensor is a resistor whose electric resistance decreases with increasing incident light intensity. A database of solar altitude, azimuth, and sunrise and sunset times is provided by this solar tracking system. Other solar trackers operating in an astronomical method may access and use this database over the Internet. Solar position and sunrise and sunset times in the database were compared with those of the Astronomical Applications Department of the U.S. Naval Observatory. The differences were found to be negligible. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
995.
C.H. Lim G. Airoldi R.G. Dominy K. Mahkamov 《International Journal of Thermal Sciences》2011,50(12):2451-2463
This paper describes the experimental validation of CFD modelling for heat transfer coefficients in an axial flux permanent magnet (AFPM) generator. A large scale low speed test rig was designed and constructed. The geometric parameters and the rotational speed of the test rig were determined by dimensional analysis, to ensure the flow characteristic remains unchanged as compared with commercial AFPM generators. The heat transfer coefficients in the test rig were measured at rotational Reynolds number, Reω from 0 to 2 × 106, non-dimensional flow rate, Cw up to 11,000 and gap ratio, G = 0.016, by using the combination of heat flux sensors and thermocouples. Due to the large size of the scaled-up rig, natural convection played a significant part in the heat transfer and this had to be compensated for in the forced convection heat transfer coefficient calculations. Extra experiments were designed and conducted to identify the effect of natural convection on the machine’s cooling. The experimentally determined results were compared to heat transfer coefficients predicted by CFD models and good agreement was obtained. 相似文献
996.
Sang Hyun AhnInsoo Choi Oh Joong KwonTaeho Lim Jae Jeong Kim 《International Journal of Hydrogen Energy》2012,37(1):41-50
CoRuPt and CoPtRu catalysts were prepared on carbon paper (CP) using various electrochemical processes including Sn sensitization, Pd activation, Co electrodeposition and galvanic displacement. The Sn-Pd process is a surface treatment that guarantees a larger number of nucleation sites on CP for subsequent Co electrodeposition by modifying the surface to be more hydrophilic. Co particles were deposited on Sn-Pd-treated CP (SCP) by controlling deposition potential and time. Then, Pt and Ru galvanic displacements were performed on the Co particles to form CoRuPt/SCP and CoPtRu/SCP catalysts. Electrochemical measurements confirmed that the CoRuPt/SCP - 1 catalyst with a 1.02 Pt/Ru surface molar ratio showed a peak potential of 741 mV (vs. NHE) for methanol oxidation and 637 mV for carbon monoxide stripping. These values were 80 and 8 mV lower, respectively, than those of a PtRu/C commercial catalyst. 相似文献
997.
Hyun-Jong ChoiJong-Jin Lee Sang-Hoon Hyun Hee-Chun Lim 《International Journal of Hydrogen Energy》2011,36(17):11048-11055
To improve the unit cell performance and stability, molten carbonate fuel cell (MCFC) matrices were fabricated using synthetic α-LiAlO2 powder and they showed mechanical and microstructural stability under thermal cycle tests. The pure α-LiAlO2 matrix demonstrated stability with high open-circuit voltage (OCV) and maximum power density during many thermal cycle tests (more than 15 repetitions). Furthermore, to minimize the change in stack height during stack start-up and to improve mechanical and microstructural stabilities of the matrix, the electrolyte-combined α-LiAlO2 matrix was optimized by controlling the mixing ratio of synthetic α-LiAlO2 and Li/K carbonate powders. The suitable electrolyte content was fixed at approximately 50 vol.% for the homogeneously filled pores of the pure α-LiAlO2 matrix. These matrices showed good microstructural stability during five thermal cycle tests in an air atmosphere at 923 K and with improved unit cell performance (0.127 W cm−2) under MCFC operating conditions.In unit cell and thermal cycling tests, the optimized matrices were stable through more than 20 repetitions. 相似文献
998.
Journal of Mechanical Science and Technology - The purpose of this study was to analyze numerically the homogeneous combustion characteristics of biodiesel and diesel fuels and to investigate the... 相似文献
999.
Dr. Joshua A. Visser Dr. Deborah Yager Dr. Schuyler A. Chambers Dr. Ji Youn Lim Xujun Cao Prof. Lynette Cegelski 《Chembiochem : a European journal of chemical biology》2023,24(18):e202300266
Escherichia coli and other Enterobacteriaceae thrive in robust biofilm communities through the coproduction of curli amyloid fibers and phosphoethanolamine cellulose. Curli promote adhesion to abiotic surfaces and plant and human host tissues and are associated with pathogenesis in urinary tract infection and food-borne illness. The production of curli in the host has also been implicated in the pathogenesis of neurodegenerative diseases. We report that the natural product nordihydroguaiaretic acid (NDGA) is effective as a curlicide in E. coli. NDGA prevents CsgA polymerization in vitro in a dose-dependent manner. NDGA selectively inhibits cell-associated curli assembly and inhibits uropathogenic E. coli biofilm formation. More broadly, this work emphasizes the ability to evaluate and identify bioactive amyloid assembly inhibitors by using the powerful gene-directed amyloid biogenesis machinery in E. coli. 相似文献
1000.
Lim SuJi Yun Choong-In Song Dahyun Kang Seok-Seong Kim Young-Jun 《Food science and biotechnology》2022,31(9):1145-1155
Food Science and Biotechnology - Oat contains a variety of phenolic compounds, including avenanthramides, which are found only in oats. This study was conducted to establish the quantitative... 相似文献