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991.
Ti/Sn/TiC powder mixtures were first employed to synthesize Ti2SnC powder by pressureless sintering in the temperature range of 950–1250 °C at vacuum atmosphere. Ti2SnC began to form at 950 °C, its content increased with increasing temperature. High purity of Ti2SnC was obtained by sintering the mixtures with deficient Sn and TiC at 1200 °C for 15 min. A reaction mechanism was proposed to explain the formation of Ti2SnC. The Ti2SnC powder was characterized by scan electron microscopy (SEM) and X-ray diffraction (XRD). Using the above mixtures and process, the Ti2SnC ceramic powder can be obtained on a larger scale. 相似文献
992.
Self-organized and highly-ordered TiO2 nanotube array with disjunctive wall-hole structure has been synthesized from titanium foil by potentiostatic–galvanostatic anodization process. The morphology and microstructure of the TiO2 layer depend greatly on the electrolyzing parameters and electrolyte components. TiO2 formation mechanism by anodization oxidation is discussed. The crystallized TiO2/Ti nanotube electrode exhibited a significant enhancement of photoelectrochemical current response in comparison with micrometer-sized TiO2/Ti multiporous electrode. Such kind of TiO2 nanotube will have many potential applications in various areas as an outstanding photoelectrochemical material. 相似文献
993.
994.
Single-crystalline β-Ga2O3 nanobelts were synthesized by a simple physical evaporation method in argon atmosphere with the starting materials of Ga. The β-Ga2O3 nanobelts have a width of 50-100 nm and width-to-thickness ratios of 5-10, and length of up to a few millimeters, which may have potential applications in nanosize sensors or optoelectronic nanodevices. 相似文献
995.
996.
997.
Optical properties were investigated of ZnO thin films grown on (100) γ-LiAlO2 (LAO) substrates by pulsed laser deposition method. C-axis oriented ZnO film was grown on (100) LAO substrate at the substrate temperature of 550 °C. The transmittances of the films were over 85%. Peaks attributed to excitons were seen in the absorption spectra, indicating that the thin films have high crystallinity. Photoluminescence spectra were observed at room temperature; the peak at 550 nm is ascribed to oxygen vacancies in the ZnO films caused by the diffusion of Li from the substrate into the film during deposition. 相似文献
998.
Xuesong Zhou Mahmassani H.S. 《Intelligent Transportation Systems, IEEE Transactions on》2006,7(1):105-114
This paper proposes a dynamic origin-destination (OD) estimation method to extract valuable point-to-point split-fraction information from automatic vehicle identification (AVI) counts without estimating market-penetration rates and identification rates of AVI tags. A nonlinear ordinary least-squares estimation model is presented to combine AVI counts, link counts, and historical demand information into a multiobjective optimization framework. A joint estimation formulation and a one-sided linear-penalty formulation are further developed to take into account possible identification and representativeness errors, and the resulting optimization problems are solved by using an iterative bilevel estimation procedure. Based on a synthetic data set, this study shows the effectiveness of the proposed estimation models under different market-penetration rates and identification rates. 相似文献
999.
Informatics challenges of high-throughput microscopy 总被引:1,自引:0,他引:1
In this article, we discussed the emerging informatics issues of high-throughput screening (HTS) using automated fluorescence microscopy technology, otherwise known as high-content screening (HCS) in the pharmaceutical industry. Optimal methods of scoring biomarkers and identifying candidate hits have been actively studied in academia and industry, with the exception of data modeling topics. To find candidate hits, we need to score the images associated with different compound interventions. In the application example of RNAi genome-wide screening, we aim to find the candidate effectors or genes which correspond to the images acquired using the three channels. Scoring the effectors is equivalent to scoring the images based on the number of phenotypes existing in those images. Our ultimate objective of studying HTS is to model the relationship between gene networks and cellular phenotypes, investigate cellular communication via protein interaction, and study the disease mechanism beyond the prediction based on the molecular structure of the compound. Finally, computational image analysis has become a powerful tool in cellular and molecular biology studies. Signal processing and modeling for high-throughput image screening is an emerging filed that requires novel algorithms for dynamical system analysis, image processing, and statistical modeling. We hope that this article will motivate the signal processing communities to address challenging data modeling and other informatics issues of HTS. 相似文献
1000.
Lin C. Wang J. Zhou H. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2006,14(11):1264-1275
Clustering (or partitioning) is a crucial step between logic synthesis and physical design in the layout of a large scale design. A design verified at the logic synthesis level may have timing closure problems at post-layout stages due to the emergence of multiple-clock-period interconnects. Consequently, a tradeoff between clock frequency and throughput may be needed to meet the design requirements. In this paper, we find that the processing rate, defined as the product of frequency and throughput, of a sequential system is upper bounded by the reciprocal of its maximum cycle ratio, which is only dependent on the clustering. We formulate the problem of processing rate optimization as seeking an optimal clustering with the minimal maximum-cycle-ratio in a general graph, and present an iterative algorithm to solve it. Experimental results validate the efficiency of our algorithm 相似文献