仅能承受轴向载荷的轴承为()。 A.向心轴承 B.推力轴承 C.向心推力轴承 D.推 发布时间:2019-01-26 01:56 │ 来源:www.tikuol.com 题型:单项选择题 问题: 仅能承受轴向载荷的轴承为()。A.向心轴承B.推力轴承C.向心推力轴承D.推力向心轴承
题型:单项选择题 (2013·皖南八校第一次联考)A recent survey shows the number of people who shop in stores ________, while far more are shopping online.A.decrease B.decreasesC.is decreasing D.are decreasing 查看答案
题型:单项选择题 甲醇质子交换膜燃料电池中将甲醇蒸气转化为氢气的两种反应原理是①CH3OH(g)+H2O(g) = CO2(g)+3H2(g);DH=+ 49.0 kJ·mol-1②CH3OH(g)+1/2O2(g) = CO2(g)+2H2(g);DH =-192.9 kJ·mol-1 下列说法正确的是A.CH3OH的燃烧热为192.9 kJ·mol-1 B.CH3OH的燃烧热为133.9 kJ·mol-1C.CH3OH转变成H2的过程一定要吸收能量D.根据②推知反应:CH3OH(l) +1/2O2(g) = CO2(g) +2H2(g)的DH >-192.9 kJ·mol-1 查看答案