2007年1月，致远大学为发展校办产业，决定将靠近商业区的一排校园围墙拆除，在旧址上

（1）金属腐蚀会造成巨大的经济损失，钢铁在潮湿的空气中更容易被腐蚀，主要原因是钢铁里的铁和碳与钢铁表面吸附的一层水膜构成许多微小的______发生电化学腐蚀，该腐蚀中负极发生的电极反应式为______．

（2）某综合实践活动小组到自来水厂进行参观，了解到源水处理成自来水的工艺流程示意图如下：

①源水中含Ca²⁺、Mg²⁺、HCO₃^-、Cl^-等，加入CaO，再通入CO₂可以降低水中Ca²⁺、Mg²⁺等离子的浓度，从而将硬水转化为______水．

②该水厂加入的A物质常为氯气，其作用是______．

③加入凝聚剂可以除去其中的悬浮固体颗粒，以下物质中不能作为凝聚剂的是（填写编号）______．

A．KAl（SO₄）₂•12H₂O　　B．Fe₂（SO₄）₃　　C．CuSO₄　　D．FeSO₄•7H₂O．

Ax, a Swedish manufacturer, contacted Bo, a German manufacturer, to enquire about Bo making special screws of a particularly high quality.Bo provided by return a list of prices and delivery periods.Ax then ordered 3,000 screws and also 3,000 specialised nuts and bolts, not mentioned before.Bo requested payment in advance or a letter of credit. Ax, in turn, asked for a pro-forma invoice.When Bo sent the invoice it listed screws of a lower quality than the original specification with their respective prices.Ax objected immediately and demanded delivery of the articles in the ‘ordered’ quality. Bo agreed to delivery of higherquality articles but insisted on a higher price than on the invoice. Ax insisted on delivery of the higher-quality items but for the price listed in the invoice.Required:Advise the parties whether or not they have entered into a binding contractual agreement on the basis of the UN Convention on Contracts for the International Sale of Goods. (10 marks)

DCS操作站死机有什么现象，如何处理？

对于室内工艺管道，安装不正确的是（）。

A.室内管路敷设应有坡度，坡度方向一般均为顺介质流动方向

B.管道与管道或设备连接中不的强力对口，不允许将管道与阀门的重量支撑在设备上

C.供液管路不应有“口袋”（即下凹现象）

D.输送易燃易爆介质的管路，不得敷设在走廊、楼梯和生活间

资产、负债、股东权益的概念及相互关系是什么