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941.
In this study, we have designed and fabricated robust hydrophobic surfaces that are composed of various micropillar arrays and investigated the effect of the aspect ratio (feature height/feature size) of the micropillar on the wettability of the fabricated surfaces. The robust, micropillar-arrayed surfaces were designed to yield the same Wenzel and Cassie water contact angles (CAs). According to our design rule, one can achieve an enhanced hydrophobic surface by increasing the height of the micropillars. The designed hydrophobic surfaces were fabricated by polydimethylsiloxane (PDMS) replica molding with photolithographically micropatterned SU-8 masters. The hydrophobicity properties of the fabricated PDMS surfaces were fully characterized theoretically and experimentally. From the theoretical and experimental results, it was found that the micropillars of an intrinsically hydrophobic material with a high aspect ratio enhance the hydrophobicity of the surface by increasing the surface roughness (in view of the Wenzel state) and the opportunities for the entrapment of air beneath a water droplet (the Cassie state). 相似文献
942.
A scanning electron microscope (SEM) is a sophisticated equipment employed for fine imaging of a variety of surfaces. In this study, prediction models of SEM were constructed by using a generalized regression neural network (GRNN) and genetic algorithm (GA). The SEM components examined include condenser lens 1 and 2 and objective lens (coarse and fine) referred to as CL1, CL2, OL-Coarse, and OL-Fine. For a systematic modeling of SEM resolution (R), a face-centered Box–Wilson experiment was conducted. Two sets of data were collected with or without the adjustment of magnification. Root-mean-squared prediction error of optimized GRNN models are GA 0.481 and 1.96×10-12 for non-adjusted and adjusted data, respectively. The optimized models demonstrated a much improved prediction over statistical regression models. The optimized models were used to optimize parameters particularly under best tuned SEM environment. For the variations in CL2 and OL-Coarse, the highest R could be achieved at all conditions except a larger CL2 either at smaller or larger OL-Coarse. For the variations in CL1 and CL2, the highest R was obtained at all conditions but larger CL2 and smaller CL1. 相似文献
943.
Chung Yon Dohn Yoo Sanghyun Kim Myoung Ho 《Knowledge and Data Engineering, IEEE Transactions on》2010,22(2):207-218
In wireless mobile computing environments, broadcasting is an effective and scalable technique to disseminate information to a massive number of clients, wherein the energy usage and latency are considered major concerns. This paper presents an indexing scheme for the energy- and latency-efficient processing of full-text searches over the wireless broadcast data stream. Although a lot of access methods and index structures have been proposed in the past for full-text searches, all of them are targeted for data in disk storage, not wireless broadcast channels. For full-text searches on a wireless broadcast stream, we firstly introduce a naive, inverted list-style indexing method, where inverted lists are placed in front of the data on the wireless channel. In order to reduce the latency overhead, we propose a two-level indexing method which adds another level of index structure to the basic inverted list-style index. In addition, we propose a replication strategy of the index list and index tree to further improve the latency performance. We analyze the performance of the proposed indexing scheme with respect to the latency and energy usage measures, and show the optimality of index replication. The correctness of the analysis is demonstrated through simulation experiments, and the effectiveness of the proposed scheme is shown by implementing a real wireless information delivery system. 相似文献
944.
Song Hak Kim Chun Keun Jang Sung Hoon Jeong Jae Yun Jaung 《Journal of the Society for Information Display》2010,18(11):994-1009
Abstract— Even though dyes have a fine resolution and good chromaticities, they are not widely used as coloring materials for color filters (CFs) due to their low thermal stability and chemical resistance. A series of azo‐dye derivatives, which consist of two cross‐linkable acrylate or methacrylate groups to improve thermal and chemical properties, have been synthesized and used to fabricate color filters. The spectral properties and chemical/thermal stabilities of the fabricated CFs were investigated by comparing dye‐based CFs, without a complicated dispersion process, but with pigment‐based CFs using dispersed pigment. Also, more properties including the development test and surface morphologies lithographic properties were studied. The synthesized azo dyes were characterized by elemental analysis, UV‐visible spectra, IR, mass, and 1H‐NMR spectra. 相似文献
945.
Sung Wook Kim Hyoung Sun Yoo Byoung‐Hwa Kwon Dong Seok Kang Minwon Suh Duk Young Jeon 《Journal of the Society for Information Display》2010,18(12):1104-1110
Abstract— In this study, organic wavelength‐converting films (WCFs) applied to InGaN blue LED‐based hybrid planar WLED has been fabricated. The organic dye layer in the WCF was formed between the upper and bottom polymer sheets by using a simple roll‐laminating technique. Subsequently, the hybrid planar WLEDs have been fabricated based upon these films. The luminous efficiency of green WCF‐based hybrid planar WLEDs with a single blue LED chip was 34.6 lm/W and that of red‐WCF‐assisted green WCF‐based hybrid planar WLEDs was 27.3 lm/W under 20 mA. The use of WCF to fabricate hybrid planar WLEDs showed better stability than that of directly coating organic color‐convergence materials (CCMs) on the LED chips. It only decreased to about 10% of the initial wavelength‐converting intensity after 1 hour of continual operation at 20 mA. 相似文献
946.
Abstract— High‐efficiency and simple‐structured red‐emitting phosphorescent devices based on the hole‐injection layer of 4,4′,4″‐tris(2‐naphthylphenyl‐phenylamino)‐triphenylamine [2‐TNATA] and the emissive layer of bis(10‐hydroxybenzo[h] quinolinato)beryllium complex [Bebq2] doped with SFC‐411 (proprietary red phosphorescent dye) have been researched. The fabricated devices are divided into three types depending on whether or not the hole‐transport layer of N,N′‐bis(1 ‐naphthyl)‐N, N'‐diphenyl‐1,1′‐biphenyl‐4,4′‐diamine [NPB] or the electron‐transport layer of SFC‐137 (proprietary electron transporting material) is included. Among the experimental devices, the best electroluminescent characteristics were obtained for the device with an emission structure of 2‐TNATA/Bebq2:SFC‐411/SFC‐137. In this device, current density and luminance were found to be 200 mA/cm2 and 15,000 cd/m2 at an applied voltage of 7 V, respectively. Current efficiencies were 15 and 11.6 cd/A under a luminance of 500 and 5000 cd/m2. The peak wavelength in the electroluminescent spectral distribution and color coordinates on the Commission Internationale de I'Eclairage (CIE) chart were 628 nm and (0.67, 0.33), respectively. 相似文献
947.
Kim SJ Zhuo S Deng F Fu CW Brown MS 《IEEE transactions on visualization and computer graphics》2010,16(6):1441-1448
This paper presents an interactive visualization tool to study and analyze hyperspectral images (HSI) of historical documents. This work is part of a collaborative effort with the Nationaal Archief of the Netherlands (NAN) and Art Innovation, a manufacturer of hyperspectral imaging hardware designed for old and fragile documents. The NAN is actively capturing HSI of historical documents for use in a variety of tasks related to the analysis and management of archival collections, from ink and paper analysis to monitoring the effects of environmental aging. To assist their work, we have developed a comprehensive visualization tool that offers an assortment of visualization and analysis methods, including interactive spectral selection, spectral similarity analysis, time-varying data analysis and visualization, and selective spectral band fusion. This paper describes our visualization software and how it is used to facilitate the tasks needed by our collaborators. Evaluation feedback from our collaborators on how this tool benefits their work is included. 相似文献
948.
Yung Bok Kim 《World Wide Web》2010,13(1-2):105-120
Web-based information services should be evaluated for accessibility and usability with various types of Internet Web-browsing devices, interacting with web information servers including directory server. A ubiquitous name-based directory server, accessible and usable with a variety of Web-browsing devices (e.g. Internet-capable mobile phones), could be a unified center for human-centric Web interaction services as well as for business models based on personalized services. We studied the accessibility and usability in user-centric Web interaction with a unified-ubiquitous name-based directory service, as metric metadata for real-time estimation. We studied the real-time metrics in synthetic approach for comparison among different services. We show empirical results based on implementation and experiments in Korea, Japan and China. 相似文献
949.
Jonghee M. Youn Minwook Ahn Yunheung Paek Jongwung Kim Jeonghun Cho 《Journal of Systems Architecture》2010,56(8):368-383
The complexity of today’s embedded applications increases with various requirements such as execution time, code size or power consumption. To satisfy these requirements for performance, efficient instruction set design is one of the important issues because an instruction customized for specific applications can make better performance than multiple instructions in aspect of fast execution time, decrease of code size, and low power consumption. Limited encoding space, however, does not allow adding application specific and complex instructions freely to the instruction set architecture. To resolve this problem, conventional architectures increases free space for encoding by trimming excessive bits required beyond the fixed word length. This approach however shows severe weakness in terms of the complexity of compiler, code size and execution time. In this paper, we propose a new instruction encoding scheme based on the dynamic implied addressing mode (DIAM) to resolve limited encoding space and side-effect by trimming. We report our two versions of architectures to support our DIAM-based approach. In the first version, we use a special on-chip memory to store extra encoding information. In the second version, we replace the memory by a small on-chip buffer along with a special instruction. We also suggest a code generation algorithm to fully utilize DIAM. In our experiment, the architecture augmented with DIAM shows about 8% code size reduction and 18% speed up on average, as compared to the basic architecture without DIAM. 相似文献
950.
Hyeon Bae Tae-Ryong Jeon Sungshin Kim Hyun-Soo Kim Dongseop Kim Seung-Soo Han Gary S. May 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2010,14(2):161-169
This study describes techniques for the cascade modeling and the optimization that are required to conduct the simulator-based
process optimization of solar cell fabrication. Two modeling approaches, neural networks and genetic programming, are employed
to model the crucial relation for the consecutively connected two processes in solar cell fabrication. One model (Model 1)
is used to map the five inputs (time, amount of nitrogen and DI water in surface texturing and temperature and time in emitter
diffusion) to the two outputs (reflectance and sheet resistance) of the first process. The other model (Model 2) is used to
connect the two inputs (reflectance and sheet resistance) to the one output (efficiency) of the second process. After modeling
of the two processes, genetic algorithms and particle swarm optimization were applied to search for the optimal recipe. In
the first optimization stage, we searched for the optimal reflectance and sheet resistance that can provide the best efficiency
in the fabrication process. The optimized reflectance and sheet resistance found by the particle swarm optimization were better
than those found by the genetic algorithm. In the second optimization stage, the five input parameters were searched by using
the reflectance and sheet resistance values obtained in the first stage. The found five variables such as the texturing time,
amount of nitrogen, DI water, diffusion time, and temperature are used as a recipe for the solar cell fabrication. The amount
of nitrogen, DI water, and diffusion time in the optimized recipes showed considerable differences according to the modeling
approaches. More importantly, repeated applications of particle swarm optimization yielded process conditions with smaller
variations, implying greater consistency in recipe generation. 相似文献