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991.
992.
介绍了一种基于RS-232总线和RS-485总线的微机继电保护系统,重点阐述了串行通信软、硬件设计方法。 相似文献
993.
A temperature-controlled, continuously and linearly tunable multiwavelength filter based on cascaded long period fiber gratings
has been realized. For the first time, a tunable wavelength range of 2.1 nm has been achieved with a temperature variation
of 62°C and a regression coefficient of 0.997. The experimental results are in good agreement with the theory. 相似文献
994.
Shengying Li Wu Yang Miao Chen Jinzhang Gao Jingwan Kang Youli Qi 《Materials Chemistry and Physics》2005,90(2-3):262-269
Nanosized lead oxide particles were prepared by thermal decomposition of lead hydroxycarbonate synthesized under microwave irradiation. Urea and lead nitrate were used as the starting materials. Microstructure and morphology of the products were investigated by means of XRD, AFM, TEM, and IR absorption spectra. The results indicated that well crystallized, finely dispersed and spherical -PbO nanoparticles with a size of ca. 30 nm were obtained. Meanwhile, an orthogonal phase β-PbO with a size of ca. 38 nm was also obtained when the calcinations temperature was up to 600 °C. In addition, a Pb(II)-selective electrode based on cellulose acetate was prepared using nanosized -PbO powders synthesized. The electrode exhibited a Nernstian slope of 29±1 mV per decade in a linear range of 2.5×10−5 mol L−1 to 1.0×10−1 mol L−1 for Pb2+ ion. The detection limit of this electrode is down to 8.0×10−6 mol L−1. This sensor has a short response time of about 10 s and could be used in a pH range of 2.0–8.0. High selectivity was obtained over a wide variety of metal ions. 相似文献
995.
Hyun-Phill Ko Sangsig Kim Chong-Yun Kang Hyun-Jai Kim Seok-Jin Yoon 《Materials Chemistry and Physics》2005,90(2-3):322-326
The contact kinetics of piezoelectric linear motors determines the operational characteristics like speed and torque or transmitted mechanical power and efficiency. Piezoelectric linear motors are driven by tangential stress in the interface between tip of shaking beam and slider. A good contact between the tip and slider is necessary for a reliable analysis of the motor, which is needed for the optimization of its performance. The piezoelectric linear motor was fabricated and the characteristics of the motor were investigated by external conditions such as tip shape with different curvatures and contact force between the tip and the slider. It was found in this investigation that the optimal curvature of the tip and the contact force are curvature of 1 and 10, respectively, for the high actuating speed, and curvature of 1 and 40 N, respectively, for the high actuating force. Finally, tip shape has an influence on the characteristics of linear motor. 相似文献
996.
The synthesis of copper monosulfide (CuS) submicrotubes under mild conditions has been achieved by two simple steps: firstly, a precursor (copper-thiosulfate complexes) was prepared through the precipitation reaction of CuSO4·5H2O and Na2S2O3·5H2O in distilled water at room temperature; then, in the absence of any extra catalyst, surfactant or template, pure submicrometer-sized CuS crystallites with a tubular morphology could be obtained just via solvothermal treatment of the precursor in ethanol at 150-180 °C for 12-24 h. Also, the effects of the reaction temperature and reaction time on the phase and morphology of the resultant products were investigated and the possible formation mechanism of tubular structure CuS crystallites in this solvothermal system was discussed. 相似文献
997.
Development of nanoparticulate materials technology is essential to processing of highly functional nanoparticulate materials and components with small and complex shape. This paper provides an overview on our recent investigations on the processing of net‐shaped nanocrystalline Fe‐Ni powder and related material property such as mechanical property. The key‐processing concept is the synthesis of nanopowders and subsequent consolidation with controlled microstructure by using powder injection molding (PIM) process. Especially, the pressureless sintering process is inevitable for consolidation of the PIMed nanopowder. The present review focuses on the densification process and related mechanical property of the PIMed Fe‐Ni nanopowder in association with microstructural evolution and diffusion process. 相似文献
998.
研究了非平衡光纤Mach-Zehnder干涉仪解调N元光纤光栅传感器阵列时的偏振衰落问题.运用邦加球和光纤偏振光传输理论,利用简化模型,通过详细的理论分析,得到优化控制下阵列传感信号最低可见度的下限表达式,并通过计算机仿真,验证了结果的正确性,并详细分析了仿真实验的结果. 相似文献
999.
1000.
营养型发酵软饮料的研究 总被引:3,自引:0,他引:3
研究利用稻加工大米的副产品碎米为主要原料 ,加入麦芽、加酶 ,进行液化、糖化、发酵等工艺 ,研制出一种发酵营养型软饮料。本产品与啤酒相比 ,可减少原料总用量的 17% ,减少麦芽用量的 2 8.6%。 相似文献