The problems about railway signal power supplypanel in China are dealt with in details, and reasons are analysed.
较为详细地介绍了我国铁路信号电源屏存在的主要问题，并分析了产生问题的原因。
2
According to the design demand of DC power supplypanel in engineering, this paper introduces the selection of rectification DC rectification power system with high-frequency switch.
针对工程中对直流电源屏的设计需要，简要介绍了高频开关整流电源直流系统的选择。
3
On the supply side (chart 2, bottom panel), the main source of new gold-what is dug out of the world's goldmines-has been flat or declining.