某热轧厂末架轧机轧辊直径为700mm，该轧辊入口处板带厚度为7.5mm，轧制成品宽度为1200mm，厚度为5.0mm的带钢。已知该轧机标定时压力F0为1200t，轧件和轧辊接触面单位轧制力P为0.14KN/mm2，轧机刚度为550T/mm，求该轧机台上显示辊缝值为多少？（保留两位小数）
参考答案：
接触弧水平投影长度为Lc
Lc＝（R×△h）1/2＝[700×（7.5－5.0）]1/2≈41.83（mm）
接触面水平投影面积为S
S＝B×Lc＝1200×41.83≈50196（mm2）
轧制力F
F＝P×S＝0.14×50196≈7027KN＝702.7（T）
设辊缝值为S，根据弹跳方程h＝S＋（F－F0）
S＝h－（F－F0）＝5.0－（702.7－1200）/550≈5.90（mm）
该轧机辊缝值为5.90mm。
| 完形填空。 | ||||
| A month after Hurricane Katrina, I returned home in New Orleans. There lay my house, 1 to waist-high ruins, smelly and dirty. Before the trip, I'd had my car 2 . When the office employee of the garage was writing up the bill, she 3 my Louisiana license plate. "You from New Orleans?" she asked. I said I was. "No 4 ," she said, and firmly shook her head when I reached for my wallet. The next day I went for a haircut, and the same thing 5 . As my wife was studying in Florida, we decided to 6 there and tried to find a rental house that we could 7 while also paying off a mortgage (抵押贷款) on our 8 house. We looked at many places, but none was 9 . We'd begun to accept that we'd have to live in extremely reduced circumstances 10 , when I got a very 11 e-mail from a James Kemmedy in California. He'd read some pieces I'd written about our 12 for Slate, the online magazine and wanted to give us ("no conditions attached") a new house 13 the lake from New Orleans. It sounded too good to be 14 , but I replied, thanking him for his exceptional 15 , that we had no plans to go back. Then a poet at the University of Florida 16 to rent his house to me while he went to England on his one-year paid leave. The rent was rather 17 . I mentioned the poet's offer to James Kemmedy, and the next day he sent a check 18 our entire rent for eight months. Throughout this painful experience, the 19 of strangers has done much to bring back my faith in humanity. It's almost worth 20 your worldly possessions to be reminded that people are really nice when given half a chance. | ||||
|
