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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
C JDBC:可扩展的数据库集群中间件 总被引:1,自引:0,他引:1
多层软件结构中已经成功地应用了集群,但在后台数据库上还缺乏这种工具,所以当数据库层出现瓶颈时,就得在硬件上花费高额的费用.开源数据库集群中间件--C-JDBC解决了上述问题.它通过JDBC接口引进了一个虚拟数据库,只要基于拥有JDBC驱动的数据库上面的应用程序,程序无须任何改动就能运行.C-JDBC具有灵活的体系结构,支持大型复杂的数据库集群体系结构,为数据库集群提供的高性能、强容错能力、易用的平台. 相似文献
72.
73.
Silicon - In this paper, an analytical model for negative capacitance double gate field effect transistor (NC-DG-FET) is proposed. This model includes interface traps and temperature effects, which... 相似文献
75.
H. B. Wu Z. T. Fan N. Y. Huang X. P. Dong X. F. Tian 《Journal of Materials Engineering and Performance》2005,14(1):132-135
The magnesium (Mg) alloy low-pressure expendable pattern casting (EPC) process is a newly developed casting technique combining
the advantages of both EPC and low-pressure casting. In this article, metal filling and the effect of the flow quantity of
inert gas on the filling rate in the low-pressure EPC process are investigated. The results showed that the molten Mg alloy
filled the mold cavity with a convex front laminar flow and the metal-filling rate increased significantly with increasing
flow quantity when flow quantity was below a critical value. However, once the flow quantity exceeded a critical value, the
filling rate increased slightly. The influence of the flow quantity of inert gas on melt-filling rate reveals that the mold
fill is controlled by flow quantity for a lower filling rate, and, subsequently, controlled by the evaporation of polystyrene
and the evaporation products for higher metal velocity. Meanwhile, the experimental results showed that the melt-filling rate
significantly affected the flow profile, and the filling procedure for the Mg alloy in the low-pressure EPC process. A slower
melt-filling rate could lead to misrun defects, whereas a higher filling rate results in folds, blisters, and porosity. The
optimized filling rate with Mg alloy casting is 140 to 170 mm/s in low-pressure EPC. 相似文献
76.
Electron Emission from Barium Strontium Titanate Ceramics 总被引:1,自引:0,他引:1
Shutao Chen Xianlin Dong Shuxin Zheng Ziqiu Zhu Chuanxiang Tang 《Journal of the American Ceramic Society》2006,89(7):2118-2122
This paper focuses on understanding the influence of materials' properties on the ferroelectric electron emission. Ferroelectric ( x =1.0 and 0.8) and paraelectric ( x =0.67 and 0.5) compositions of barium strontium titanate (Ba x Sr(1− x ) TiO3 ) system were chosen for study based on their different ferroelectric and dielectric properties. Similar emission current waveforms were obtained from four compositions with negative triggering voltage applied to the rear electrode of the samples. It was difficult to explain the experimental results using the spontaneous polarization-switching model. The mechanism of electron emission from Ba x Sr(1− x ) TiO3 ceramics was ascertained to surface plasma emission. 相似文献
77.
丝状真菌纤维素酶合成机制的研究 总被引:3,自引:0,他引:3
丝状真菌产生的纤维素酶被认为是最有应用前景的,但就目前酶生产效率来看,离实际应用还有很大的差距,需要对酶的合成调节机制有更为全面和深刻的了解。纤维素酶的生物合成受诱导和阻遏双重控制,酶的生产既有赖于低廉的保持一定浓度诱导物的存在,又必须清除分解代谢产物对酶合成的阻遏,其中的详细机制有待进一步的阐明。真菌纤维素酶的分泌也是相当复杂的,在酶的分泌过程中,酶会发生例如糖基化等一系列变化。提高纤维素酶的活力测定方法的准确性,使其进一步规范化,是研究纤维素酶工作的另外一个重要的领域。随着现代生物学朝着分子水平的不断发展,分子生物学的许多方法也越来越多地被应用于纤维素酶的研究中,并取得了重要进展。对真菌纤维素酶合成调节机制的深入研究,将为提高纤维素酶产量,推动应用工作的发展打下理论基础。 相似文献
78.
79.
Kyoung Duck Seo Jang Min Park Hyeonsoo Jeong Dong Sung Kim 《Microsystem Technologies》2014,20(2):243-250
We develop a miniaturized batch-type screw mixer (BSM) for uniform mixing of polymer resin and nanoparticles, based on the stretching of material elements. This stretching is induced by the combination of recirculating cross-sectional flows in deep channels of the screw and high shear stress developed at flight regions. The BSM is used to produce a polymer nano-composite composed of multi-walled carbon nanotubes and polydimethylsiloxane resin. The mixing performance of the BSM is characterized quantitatively by estimating two different types of mixing efficiencies (i.e., dispersive mixing and distributive mixing) via transmitted light microscope images. The developed BSM highly improves the mixing performance rather than that of a conventional ultrasonic mixing device. 相似文献
80.
Dong Won Cho Young Hae Lee Tae Youn Lee Mitsuo Gen 《Journal of Intelligent Manufacturing》2014,25(5):1025-1042
In this paper we propose an adaptive genetic algorithm that produces good quality solutions to the time dependent inventory routing problem (TDIRP) in which inventory control and time dependent vehicle routing decisions for a set of retailers are made simultaneously over a specific planning horizon. This work is motivated by the effect of dynamic traffic conditions in an urban context and the resulting inventory and transportation costs. We provide a mixed integer programming formulation for TDIRP. Since finding the optimal solutions for TDIRP is a NP-hard problem, an adaptive genetic algorithm is applied. We develop new genetic representation and design suitable crossover and mutation operators for the improvement phase. We use adaptive genetic operator proposed by Yun and Gen (Fuzzy Optim Decis Mak 2(2):161–175, 2003) for the automatic setting of the genetic parameter values. The comparison of results shows the significance of the designed AGA and demonstrates the capability of reaching solutions within 0.5 % of the optimum on sets of test problems. 相似文献