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81.
This paper presents a method to make vanadium dioxide (VO2) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100nm. The phase transition temperature of VO2 is 65°C. The transmittance of the semiconducting phase VO2 is about 50% and it is reduced to as low as 3% in metal phase at the infrared wavelenghth spectrum. The extinction ratio of the optical switches is 12dB. and the insertion loss is of 1-2dB. The switching time is about 1ms.  相似文献   
82.
The solar photocatalytic degradation of methyl parathion was investigated using a circulating TiO2/solar light reactor. Under solar photocatalysis condition, parathion was more effectively degraded than solar photolysis and TiO2-only conditions. With solar photocatalysis, 20 mg/L of parathion was completely degraded within 60 min with a TOC decrease of 63% after 150 min. The main ionic byproducts during photocatalysis recovered from parathion degradation were mainly as NO3-, NO2- and NH4+, 80% of the sulphur as SO4(2-), and 5% of phosphorus as PO4(3-). The organic intermediates 4-nitrophenol and methyl paraoxon were also identified, and these were further degraded in solar photocatalytic condition. Two different bioassays (Vibrio fischeri and Daphnia magna) were used to test the acute toxicity of solutions treated by solar photocatalysis and photolysis. The Microtox test using V. fischeri showed that the toxicity expressed as EC50 (%) value increased from 5.5% to >82% in solar photocatalysis, indicating that the treated solution is non-toxic, but only increased from 4.9 to 20.5% after 150 min in solar photolysis. The acute toxicity test using D. magna showed that EC50 (%) increased from 0.05 to 1.08% under solar photocatalysis, but only increased to 0.12% after 150 min with solar photolysis, indicating the solution is still toxic. The pattern of toxicity reduction parallels the decrease in TOC and the parathion concentrations.  相似文献   
83.
流场拟合法是由何继善院士提出的物理探测技术。以流场拟合法为理论基础研制的管涌渗漏检测仪在堤坝检测及抗洪抢险中发挥了重要作用,本文提出了一种在缩微环境中模拟管涌渗漏,对流场拟合法进行模拟测试并获得了明显的结果。为管涌仪器的性能检测、校验、标定提供了便捷的测试方法,并为该仪器在生产过程中统一性能和企业标准的制订提供了理论依据。  相似文献   
84.
Hyperspectral image fusion is a key technique of hyperspectral data processing. In recent years, many fusion methods have been proposed, but there is little work concerning evaluation of the performances of different image fusion methods. In this paper, a method called quantitative correlation analysis (QCA) is proposed, which provides a quantitative measure of the information transferred by an image fusion technique into the output image. Using the proposed method, the performances of different image fusion methods can be compared and analyzed directly based on the images of before and after performing the fusion. The correlation information entropy, based on the developed QCA, is also proposed and testified by numerical simulations. Typical hyperspectral data are applied to the proposed method. The results show that the method is effective, and its conclusions agree with the classification results in applications.  相似文献   
85.
房沂 《中国井矿盐》2006,37(2):36-40
本文对发电机同轴励磁机电刷火花过大的原因进行了分析.并针对这些原因提出了相应的处理办法。对规范励磁机的运行维护有很大的帮助。  相似文献   
86.
The charge storage characteristics of P-channel Ge/Si hetero-nanocrystal based MOSFET memory has been investigated and a logical array has been constructed using this memory cell. In the case of the thickness of tunneling oxide T_ox=2nm and the dimensions of Si- and Ge-nanocrystal D_Si=D_Ge=5nm, the retention time of this device can reach ten years(~1×10~8s) while the programming and erasing time achieve the orders of microsecond and millisecond at the control gate voltage |V_g|=3V with respect to N-wells, respectively. Therefore, this novel device, as an excellent nonvolatile memory operating at room temperature, is desired to obtain application in future VLSI.  相似文献   
87.
88.
周熠 《信息技术》2003,27(8):70-72
ASP技术由于其方便 ,灵活及可扩充性等特点和简明、高效的技术优势 ,在Web数据库的开发中获得了广泛的应用。简述了开发Web数据库的重要性 ,介绍了ASP技术的特点及其数据库访问原理 ,ADO对象。实例介绍了ASP实现医院门诊在线查询的方法  相似文献   
89.
Yi CS  Zeczycki TN  Guzei IA 《Organometallics》2006,25(4):1047-1051
The tetrametallic ruthenium-oxo-hydroxo-hydride complex {[(PCy(3))(CO)RuH](4)(mu(4)-O)(mu(3)-OH)(mu(2)-OH)} (1) was synthesized in two steps from the monomeric complex (PCy(3))(CO)RuHCl (2). The tetrameric complex 1 was found to be a highly effective catalyst for the transfer dehydrogenation of alcohols. Complex 1 showed a different catalytic activity pattern towards primary and secondary benzyl alcohols, as indicated by the Hammett correlation for the oxidation reaction of p-X-C(6)H(4)CH(2)OH (rho = -0.45) and p-X-C(6)H(4)CH(OH)CH(3) (rho = +0.22) (X = OMe, CH(3), H, Cl, CF(3)). Both a sigmoidal curve from the plot of initial rate vs [PhCH(OH)CH(3)] (K(0.5) = 0.34 M; Hill coefficient, n = 4.2+/-0.1) and the phosphine inhibition kinetics revealed the highly cooperative nature of the complex for the oxidation of secondary alcohols.  相似文献   
90.
单井注水吞吐在塔河油田的应用   总被引:3,自引:0,他引:3  
在塔河油田开发生产过程中,个别油井在修井作业中出现先漏后喷的现象。在修井完成后,产量较前期有大幅增加。针对这类油井进行单井注水吞吐采油试验,研究发现钻遇定容封闭性油藏的油井适合单井注水吞吐开采。一方面利用油水重力分异,抬升油水界面,增加采出量;另一方面注水补充地层能量,恢复地层压力。该方法在塔河油田实际应用中,取得了较好的效果和较高的经济效益,也为提高定容封闭性油藏油井的采收率提供了一个较好的方法。  相似文献   
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