多谐波源小电网的无源滤波技术应用

无源滤波器一般存在滤波频段窄、依赖系统阻抗特性等缺点,这使其应用于谐波频谱复杂、波动严重的电网变得十分困难。本文结合某多谐波源的区域电网上无源谐波治理的实际应用案例,详细描述了设计该套滤波装置的分析和仿真过程,并给出相关的治理效果,具有一定工程应用价值。     

基于电子模拟计算机的动力学等效实验

电子模拟计算机,动力学,等效实验,仿真,非线性时变系统基于电学和动力学的广泛相似性,针对动力学实验复杂、可观测性差的实际,用电子模拟计算机实现动力系统的传递函数和基本算子,将动力学实验问题转化为电问题,从而可以利用成熟的电测量技术完成动力系统的仿真和实验.给出了基于电子模拟计算机的动力系统的基本元件的等效模型、典型动力系统的等效模拟和等效实验系统构架.模拟及仿真结果表明,文中方法简单、正确,应用范围广.     

预见PWM控制在轧机调速系统中的应用

首先介绍了单传动轧机主传动调速系统的硬件结构,然后阐述了最优预见PWM控制原理及其工程应用。预见PWM控制新技术在轧机主传动调速系统中的成功应用解决了在采用PWM技术载波频率较低的情况下波形失真较高的问题,消除了脉动转矩,提高了控制精度,延长了功率开关器件的使用寿命。实践证实了这一新技术的有效性。     

Erosive wear of selected metals in coal washing environments

A slurry erosive wear apparatus developed by the authors has been used to test the erosive wear behaviour of selected metals in coal washing environments. The erosive wear test machine was employed to determine the effects of (1) carbon content in carbon steels, (2) chromium content in alloy steels, and (3) corrosion of aqueous solutions on the erosive wear behaviour of metals. The test results revealed that the carbon content in annealed carbon steels slightly affects the erosive wear resistance of metals, while the increase in chromium content of alloy steels apparently improves the erosive wear resistance of metals and, when a corrosion inhibitor is added to slurries, the erosive wear rates of metals reduces significantly. Two types of micro-mechanism were deduced from the observation of eroded surfaces by SEM: (1) local exfoliation, and (2) micro-cutting. The corrosion inhibitor can alter the micro-mechanism from local exfoliation to micro-cutting. The analyses show that the erosive wear of selected metals in slurries results from the synergistic effects of wear by solid particles plus fluid corrosion.     

cdma2000 1x EV-DO下行无线链路预算

1x EV-DO是cdma2000 1x系统的演进,在cdma2000 1x的基础上能够提供高速移动数据传输业务.本文简要介绍了1x EV-DO的技术特点和前向链路的时隙结构,并对前向链路在不同传输速率条件下所能达到的覆盖范围进行了估算,结合估算结果对1x EV-DO系统进行实例分析,分析结果说明1x EV-DO系统很难提供3G标准所规定的静止环境2048kbit/s的无线接入速率,只有当用户数有限且传输信道质量优良的条件下,才有可能提供大约600kbit/s的最高无线接入速率.     

An applied research on approach of dyadic wavelet transform for Remote Sensing image edge detection

In the edge detection of Remote Sensing （RS） image, the useful detail losing and the spurious edge often appear. To solve the problem, the authors uses the dyadic wavelet to detect the edge of surface features by combining the edge detecting with the multi-resolution analyzing of the wavelet transform. Via the dyadic wavelet decomposing, the RS image of a certain appropriate scale is obtained, and the edge data of the plane and the upright directions are respectively figured out, then the gradient vector module of the surface features is worked out. By tracing them, the authors get the edge data of the object, therefore build the RS image which obtains the checked edge. This method can depress the effect of noise and examine exactly the edge data of the object by rule and line. With an experiment of an RS image which obtains an airport, the authors certificate the feasibility of the application of dyadic wavelet in the object edge detection.     

汽轮机驱动给水泵应用与节能分析

介绍了汽轮机驱动给水泵的基本原理和适用条件,哈尔滨气化厂实际使用情况和经济效益分析,证实了汽轮机驱动给水泵的节能效果十分显著,可予以推广。     

轻钢平台主梁受力和变形试验研究及理论分析

应用结构试验方法和理论分析方法研究了轻钢结构中平台主梁的受力和变形,获得了连续3跨轻钢平台工字型主梁中跨跨中截面挠度计算公式。依据不同的条件,借助标准有限元通用程序对理论公式和试验公式进行了验证分析,揭示了两种研究方法结果形成差异的原因。研究结果对新结构的设计和在役结构的使用监控有参考价值。     

高效液相色谱-四极杆飞行时间串联质谱法解析桑椹酒渣中的酚类物质

该研究通过研究桑椹酒渣中的酚类化合物,为开发酒渣的价值提供一定的理论基础和数据支撑。建立云桑二号桑椹酒渣中的酚类化合物的高效液相色谱-四极杆飞行时间串联质谱法（HPLC-Q-Time-of-Flight Mass Spectrometry,HPLC-Q-TOF-MS）定性分析方法。液相色谱使用ZORBAX SB-Aq(2.1 mm×100 mm,1.8-Micron）色谱柱,流动相为乙腈和0.1%(V/V）甲酸水溶液,梯度洗脱,采用ESI离子源在负离子模式进行质谱检测。最终鉴定出云桑二号桑椹酒渣中酚类物质共14种。然后利用标准品对照高效液相色谱法（High Performance Liquid Chromatography,HPLC）对高效液相色谱-四极杆飞行时间串联质谱法鉴定出的多酚类化合物进行了定量测定,发现桑椹酒渣中的酚类物质组成与桑椹大致相同。但各单体酚含量总体降低。其中,花青素类酚类物质含量最高的是天竺葵素-3-葡萄糖苷（718.30μg/g）,非花青素类多酚物质含量最高的是儿茶素（1 805.87μg/g）。这些结果表明桑椹酒渣酚类含量丰富,是开发健康食品的良好原料。     

用乳液法合成丙烯酸丁酯-甲基丙烯酸共聚胶乳

采用乳液聚合法合成了丙烯酸丁酯和甲基丙烯酸共聚胶乳,用红外光谱对胶乳的结构进行了表征,讨论了加料方式、水油体积比和引发剂与胶乳性能的关系。结果表明,聚合中分3次加料可使反应更平稳地进行;控制水油体积比在1.50左右更易于反应的控制,胶乳性能也较好;引发剂质量分数为0.2%~0.4%时反应体系稳定,胶乳中的单体残留量少,共聚胶乳的性能较好。