无地址的信——罗刹女与猕猴结合神话之民族学解读

神话讲述的是宇宙的形成和人类的起源,它包容了宗教、巫术、风俗、艺术、哲学等在内的综合文化现象,具有人类文化史的意义。在藏区广为流传的罗刹女与猕猴结合的神话蕴含着这样的历史真实:早期的藏族先民对于人类起源的认识具有一定的正确性,并与达尔文的进化论惊人地吻合,青藏高原上很早就有人类生存,而现代藏族人的先民主要就是土生土长的青藏高原古代居民。     

用于高压电子式电流互感器的能力和数据复合光纤传输系统

This paper describes a prototype power delivery system developed for high voltage electronic current transformer (ECT) that uses laser light to transfer power to and communicates with the primary converter. The design is based on optical-to-electrical power converters, solid-state diode lasers and optical fibers. Command signals are transmitted via the same up-fiber used to send power from secondary power supply to primary converter. The upward data transmission is completed during the brief interruption of power delivery without affecting steady power-supply. A simple comparator added to the primary converter can take the command data. Experimental results show that the fibers can provide reliable up-link for data transmission at 200 kb/s from the secondary to the primary converter. Based on the delivery system, the secondary converter can control three auxiliary channels to provide additional information. These monitoring channels are used in a time-multiplexing mode to provide information about the operation temperature, voltage and current at the remote unit for monitoring the ECT. This preventive maintenance or built-in test can increase reliability by giving early warning for necessary maintenance request.     

玻璃化温度测试在干式变压器浇注中的应用

介绍了环氧树脂的玻璃化温度测试实验,提出将玻璃化温度测试应用于干式变压器的浇注过程中。通过对玻璃化温度曲线的分析,判断其固化情况,及时了解干式变压器的浇注情况。对比玻璃化温度结果可以判断出浇注原料配比的值,从而了解设备情况,控制产品质量。     

基于ANSYS/Maxwell的感应滤波配电变压器设计与实验研究北大核心

该文提出了一种适用于低压配电网系统下的新型感应滤波配电变压器设计方法,并将其应用于综合性创新实验的教学案例中。在感应滤波配电变压器的设计中,将感应滤波技术应用于采用Ddy联结组别的配电变压器中。通过建立电路数学模型,推导阀侧产生的谐波电流与网侧电流之间的关系,揭示感应滤波配电变压器的滤波特性。该文采用ANSYS/Maxwell软件建立新型变压器的3D模型,在模型上通过仿真能量法对比工程磁路法,验证变压器绕组间短路阻抗满足技术要求;并通过磁路耦合添加滤波支路,监测变压器的网侧电流,验证其可以有效滤除电网谐波污染。最后通过实验验证了所设计的变压器的正确性和有效性,进一步激发了学生的学习兴趣和创新热情。