问题
问答题 简答题
高压熔断器与低压熔断器的型号是如何表示的？
答案
参考答案：
高压熔断器型号意义如下：
第一个字母：产品代号：R――熔断器
第二个字母：使用环境：N――户内式；W――户外式
第三个数字：产品代号
第四个数字：额定电压，千伏
第五个字母：结构特点：H――带有限流电阻；Z――带重合闸；T――带热脱扣器
搜题请搜索小程序“爱下问搜题”
高压熔断器与低压熔断器的型号是如何表示的？
参考答案：
高压熔断器型号意义如下：
第一个字母：产品代号：R――熔断器
第二个字母：使用环境：N――户内式；W――户外式
第三个数字：产品代号
第四个数字：额定电压，千伏
第五个字母：结构特点：H――带有限流电阻；Z――带重合闸；T――带热脱扣器
阅读下面短文，从短文后各题所给的四个选项（A，B，C，D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。 For centuries, magicians have used various ways to shock the audience. We all have seen how a 36 performer carefully steps 37 a bed of burning coals -- barefoot. Then he walks across 38 a single burn on his feet. Is it mind over matter, or is it just physics? As it turns __39 , walking on burning coals isn’t that hot as 40 . “The coals are hot enough to 41__ you, but if you walk quickly across them you 42 being burned.” says Jonathan Hall, a physician at Penn State University in Eric Pennsylvania. That’s because some coals are made 43 burning wood chips. Wood has two 44__ properties（特性）for fire-walking, explains Hall. First, wood is an insulator（绝缘体）--it doesn’t __45 heat very well. “It 46 _ time for heat to travel 47 the wood to your feet.” Hall says. If the performer walked across red-hot metal 48 , that would truly be 49 , because metal conducts, or transmits, heat very well. The metal would 50 burn a performer’s feet. Second, wood has a low specific heat-- it doesn’t take much heat to 51 its temperature. Heat is a form of 52 . Temperature is a 53 of heat, in units of degrees. So 54 the coals are hot, the value（数值）of heat energy they contain is low. Thus, a well-trained performer can 55 such an amazing result. Still, you don’t want to walk on burning coals, do you?
|