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- The hardness and thickness of coal seam play a great role in the vertical distribution of stress in coal and the occurrence of rock bunt under the condition of hard roof and hard floor. 在“两硬”条件下，煤层厚度与硬度的变化对煤体中的应力分布有着很大的影响，从而对煤岩体系统中冲击矿压的发生有着很大的影响。
- Electrical haulage shortwall miner and its fully mechanized mining technology under condition of hard roof and hard floor 两硬条件下短壁电牵引采煤机和短壁综采技术
- hard roof and hard floor 坚硬顶底板
- 7.The hardness and thickness of coal seam play a great role in the vertical distribution of stress in coal and the occurrence of rock bunt under the condition of hard roof and hard floor. 研究表明,煤层围岩岩体结构控制了煤层瓦斯的赋存,岩体结构可用岩层效应厚度影响系数来表示,应用这一参数研究煤层瓦斯赋存比用煤层顶板岩性及含砂率更科学。
- PS: Place the internal parts on the clean and hard floor. 将内部零件放置于干净及硬质的板面上。
- Common fault and countermeasure of elementary mining in top-coal caving face with big dip and hard roof and thick seam 大倾角坚硬顶板较薄厚煤层综放面初采常见事故及防范措施
- A maximum air movement of 3000 cfm for raped drying of carpet and hard floor. 调节三档不同的空气流动速度可以适应不同的地机情况；
- hard roof and hard coal 两硬条件
- Main application fields: cleaning companies, hotels, conference halls, banks and big offices, shopping centres, schools, airports and all places with large or middle-sized surfaces of carpet and hard floor. 主要应用领域：保洁公司、酒店、会议大厅、银行、大型办公场所、购物中心、学校，飞机场以及所有铺设中到大面积地毯和硬地板的场所。
- He fell over the roof and dashed out his brains on a pile of stones below. 他从屋顶上掉下来，摔在下面的一个石堆上，撞得脑浆迸裂。
- Bare feet pattered along the hard floor. 光着的脚板在硬地板上啪嗒啪嗒地走。
- We sought long and hard but found no answer. 我们费力多时也未找到答案。
- There is a hole in the roof and it is raining in. 房顶上有个洞，雨水从洞里落进来。
- I had to think long and hard before I could find the answer. 我要用很长时间用心想想才可找出答案。
- I'll climb up on the roof and go down the chimney. 我将爬上屋顶，从烟囱中下去。
- His argument is logical and hard to fault. ＂他的论据逻辑严密，无懈可击。＂
- I've repaired the roof and it's quite sound now. 我修了屋顶，现在它挺坚固的。
- Controlling Design of Working Face with Thick and Hard Roof 厚层坚硬顶板采场控制设计
- Use: windows of roof and balcony. 用途：屋顶窗，阳台窗。
- Information about the crisis was sketchy and hard to get. 关于这次危机的消息所知甚少并且很难获得。
