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51.
工作流技术及其应用研究   总被引:6,自引:0,他引:6  
文章介绍了工作流技术及其发展历史,对工作流的系统模型进行了详细分析,探讨了工作流技术在企业管理信息系统中的实际应用。  相似文献   
52.
容错技术广泛应用于各个行业来保证系统的冗余和可靠性。文章在分析比较当前的双机容错系统的性能优缺点后,提出了一种全新的基于“层”模式的双机容错系统解决方案。按照这种模式,可以从链路层到应用层构建一个通用的系统级的双机容错系统。文章对其实现的关键技术进行了阐述。  相似文献   
53.
介孔材料制备及研究进展   总被引:4,自引:0,他引:4  
介孔材料是一类孔径分布在1.5~50nm之间的多孔材料,具有比表面积大,孔隙率高,孔径分布窄,孔排布有序的特点,在催化、分离等领域具有广阔的应用前景。综述了介孔材料近些年在制备、应用、机理等方面的最新进展与前景展望。  相似文献   
54.
Ball-milling method was applied to dissolve Fe into titanium dioxide (TiO2). X-ray diffraction indicated the starting anatase changed to a rutile-type structure with oxygen deficiency after ball milling. Transmission electron microscopy and X-ray absorption experiments were conducted to examine the possible existence of magnetic impurities in the ball-milled powders after they were leached in HCl solutions. Temperature dependence of the resistivity shows semiconducting behavior and the magnetic hysteresis loops at 5 and 300 K exhibit ferromagnetic characteristics. Fe-doped TiO2 films were also prepared by pulsed laser deposition. The magnetic properties of the films are discussed.  相似文献   
55.
UC3875在超声电源功率控制系统中的应用   总被引:7,自引:0,他引:7  
根据超声波发生器的功率控制系统原理 ,阐述了移相控制策略对超声波发生器输出电压波形的影响 ,介绍了移相控制专用芯片UC3875的电路结构和使用设计方法。  相似文献   
56.
本文介绍M16C平台在先进的数字液晶电视技术以及硬件配置和软件算法方面的作用,同时也将讨论其他的LSI。此外,也为电视制造商用于26英寸或以上液晶电视提供主要解决方案。  相似文献   
57.
Thelwall  Mike  Tang  Rong 《Scientometrics》2003,58(1):155-181
The Web has become an important means of academic information exchange and can be used to give new insights into patterns of informal scholarly communication. This study develops new methods to examine patterns of university Web linking, focusing on Mainland China and Taiwan, and including language considerations. Multiple exploratory investigations into Web links were conducted between universities in these two places. Firstly, inlinks were counted to each university Web site from its national peers using four alternative Web document models. The results were shown to correlate significantly with research productivity in Taiwan but not in the Mainland, although in the latter case less reliable institutional data could have been the cause. For Taiwan, this is the first evidence of a scholarly association with academic linking for a non-English speaking region. It was then ascertained that the same link counts associated more strongly with scientific than social scientific research productivity in Taiwan. This confirms the general assumption of greater Web use by the hard sciences. We then investigated Taiwan-Mainland university cross-links, and found that although English is extensively used on the Web, there was no evidence that it was the language of preference for informal scholarly communication between the two areas. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
58.
This paper proposes a novel low-leakage BiCMOS deep-trench (DT) diode in a 0.18-/spl mu/m silicon germanium (SiGe) BiCMOS process. By means of the DT and an n/sup +/ buried layer in the SiGe BiCMOS process, a parasitic vertical p-n-p bipolar transistor with an open-base configuration is formed in the BiCMOS DT diode. Based on the two-dimensional (2-D) simulation and measured results, the BiCMOS DT diode indeed has the lowest substrate leakage current as compared to the conventional p/sup +//n-well diode even at high temperature conditions, which mainly results from the existence of the parasitic open-base bipolar transistor. Considering the applications of the diode string in electrostatic discharge (ESD) protection circuit designs, the BiCMOS DT diode string also provides a good ESD performance. Owing to the characteristics of the low leakage current and high ESD robustness, it is very convenient for circuit designers to use the BiCMOS DT diode string in their IC designs.  相似文献   
59.
The molecular mechanics (MM) method with COMPASS force field was used to study the H-bonds in the polyether based polyurethane model molecules. Availability of the calculation was firstly verified in comparison of some H-bonded model molecules, which were studied by using ab initio calculation, and those calculated by MM. Based on a urethane model molecule 1,3-dimethylcarbamate, which can be donor or acceptor and behaves in various conformations, it is reasonable to have a large number of H-bond interactions between various conformational donors and acceptors. For examining all the possible interaction patterns, we studied 57H-bond complexes. This systematic modeling covers well-known four types of interaction patterns, such as NH?OC (Type I), NH?O-CO (Type II), NH?NH (Type III), NH?COC (Type IV) in the system. Obtained H-bond energies were used to analyze the probabilities of the complexes. For the interaction within the hard segments, or Type I, Type II and Type III, a predominant H-bond complex has been found in the present study, which belongs to Type I. For the interaction between the hard segment and the soft segment, two conformations of Type IV were calculated to be existed.  相似文献   
60.
研究了垂直腔面发射激光器 (VCSEL)及其列阵器件的光谱特性、调制特性、高频特性及与微电子电路的兼容性 ,将 1× 16的VCSEL与CMOS专用集成电路进行多芯片组装 (MCM ) ,混合集成为 16信道VCSEL光发射功能模块 .测试过程中 ,功能模块的光电特性及其均匀性良好 ,测量的 - 3dB频带宽度大于 2GHz.  相似文献   
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