利用湿法刻蚀的方式制备黑硅

采用一种简便的方法制备出具有很好光吸收性能的黑硅材料,利用化学气象沉积和光刻的方式在硅片（100）表面形成圆形Si3N4掩膜,然后采用两种湿法刻蚀相结合方式来制备黑硅材料。首先采用碱刻蚀的方式对硅片进行各向异性刻蚀,刻蚀完成后在硅片表面形成尖锥形貌;后期利用金纳米颗粒作为催化剂,采用酸刻蚀的方式对硅片表面进行改性,在硅片表面形成多孔结构。这种黑硅材料在250～1000nm波段的光吸收率可以达到95％以上。     

石油套管偏梯形螺纹的研制

主要介绍了石油套管偏梯形螺纹的特点及开发制造过程中出现的问题,并针对各种问题的出现提出了行之有效的解决方法.经过工艺改进和螺纹参数的控制,使得石油套管偏梯形螺纹研制成功,填补了包钢20多年来不能生产偏梯形螺纹套管的空白.     

First-principles optical calculations of AsNMg3 and SbNMg3

The structural, electronic and optical properties of antiperovskite semiconductors AsNMg₃ and SbNMg₃ have been studied using the full-potential augmented plane wave plus local-orbital (APW+lo) method. The exchange correlation has been treated using the generalized gradient approximation (GGA). The equilibrium lattice constant and other structural properties have been determined. The AsNMg₃ is found to be a direct band gap semiconductor while SbNMg₃ is indirect. The results for electronic band structures, density of states, charge densities as well as optical properties are presented and discussed.     

Photonic theory of noise

The paper proposes that 1/f noise in materials and devices under non-equilibrium conditions is of electromagnetic origin rather than being related to charge carriers. For samples represented by simple resistors the analysis shows that the noise is due to the discrete nature of photons constituting the impinging electromagnetic flux from the source feeding the resistor. The paper presents detailed analysis of the external and internal electromagnetic fields of the resistor environment, with appropriate interpretation in terms of discrete photons. From quantum theory photons are known to retain their energy under interactions in linear environments. This property implies a departure from macroscopic electromagnetics in that photons cannot be partially transmitted and partially reflected, a phenomenon requiring appropriate modifications of boundary conditions at the resistor surface. These special demands call for inclusion of a supplementary internal resistor mode, serving as a lossless idler which is active only for matching purposes. At the resistor terminals the impinging photons give rise to excitation of RF current and voltage noise with an exact 1/f frequency distribution, which is in agreement with all available experimental measurements. The paper presents detailed formulae for noise spectral densities under general drive conditions from DC and RF sources of arbitrary internal resistance. The presented theoretical noise formulae have the same form as earlier empirical formulae for 1/f noise. With an RF source at frequency f₀ the analysis predicts noise with 1/|f-f₀| frequency distribution, which is compatible with available experimental observations.     

巨型水力发电厂黑启动的研究与实践

结合电网架构和溪洛渡右岸电厂实际情况,深入研究了溪洛渡右岸电厂黑启动的必要性、方式选择、注意事项、试验过程。试验结果表明,在南方电网整个系统因故障停运后,溪洛渡右岸电厂发电机组具备黑启动条件,满足黑启动要求。     

基于神经网络的行波超声波电动机起动控制

由于行波超声波电动机特殊的运行机理和结构特点,使其难以高转速直接起动。针对该问题,设计了参数在线自适应调节的转速控制器,以实现超声波电动机的高转速起动控制。采用神经网络实现控制器参数的在线自适应调节,以适应不同转速给定值的起动要求,充分发挥电机能力。实验表明,电动机起动快速准确,控制算法有效、可靠。     

基于单片机控制的异步电机磁控软起动系统的设计

分析了磁控电抗器的电路结构和工作原理,介绍了磁控软起动系统,给出了以80C196KC为主控单元的硬件电路图。软件设计方面给出了主程序流程图及子程序流程图,并对磁控软起动过程进行了仿真研究。     

基于矢量变频技术的冰箱压缩机控制系统设计

介绍了一种小型制冷变频压缩机的驱动控制器,该系统以永磁同步电机压缩机为控制对象,采用无传感器矢量控制技术,设计出了一套以TMS320F2812为核心芯片的矢量变频调速控制系统。经样机相关试验表明,该控制系统具有较宽的调速范围以及良好的动静态性能。     

有源滤波器关键技术研究

研究了有源滤波器APF的起动与运行时的直流侧电压稳定两个实用化关键技术。分析了起动过程中和IGBT的死区对直流侧电压稳定的影响问题。提出了一种改进的起动方式和通过判断IGBT桥臂电流的方式设计死区的解决方案。最后用仿真软件PSCAD/EMTDC和搭建实验平台做了仿真实验验证,证明了所提方案的合理性,为APF实用化进一步的研究提供帮助。     

山东电网黑启动试验

根椐山东电网黑启动电源点的分布和电网的结构特点,制定了基于泰山电站的山东电网黑启动试验方案。成功进行了对用电负荷零影响的情况下,远距离黑启动大型火电机组的试验,提高了突发事件的应急能力。通过录波数据,分析了抽水蓄能机组黑启动运行模式、空载充电长线路、空充变压器、大型电动机的起动以及黑启动子系统并网等特性,验证了计算方法正确性和黑启动方案的合理性。