问题
问答题 简答题
简述镀铬过程的特点
答案
参考答案:
(1)电流效率低;
(2)采用铬酸作为主盐;
(3)采用不溶性阳极;
(4)需设计特殊夹具;
(5)温度和电流密度要严格配合;
(6)采用的电流密度较高;
(7)镀前表面处理要求严格;
(8)镀铬过程中必须添加一定量的外加阴离子。
简述镀铬过程的特点
参考答案:
(1)电流效率低;
(2)采用铬酸作为主盐;
(3)采用不溶性阳极;
(4)需设计特殊夹具;
(5)温度和电流密度要严格配合;
(6)采用的电流密度较高;
(7)镀前表面处理要求严格;
(8)镀铬过程中必须添加一定量的外加阴离子。
完形填空 阅读下面短文,理解大意,然后从各小题的四个选项中,选出一个最佳答案,使短文连贯完整。 During the weekend, I usually like to __1__at home, but sometimes I like to go out for a walk 2 play football. My friend Jack works hard__3__ the week. At the weekend, he always goes to__4 his uncle and aunt work on their farm with his family.The__5__is not very big, but there is always so much to_6__ on a farm. The children look__7__ the animals and give them food. Jack and his wife help them work_8__ the fields (田野). At the end of the day, they are all___9__ and tired. After Jack’s aunt_ 10__ them a big meal, they go back home in a car.
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