排序方式: 共有53条查询结果,搜索用时 312 毫秒
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设计开发了工程制图习题自动批改与辅导系统,以“双主模式”的教学设计为指导,研究了多操作平台间图形交互的集习题解答、在线讨论、在线答疑、动画模拟、操作练习和自动批改为一体的动态交互系统,实现理论教学和实践教学的适时交互。 相似文献
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Using ploughing-extrusion method, a cross-connected finned micro-grooves structure was formed on the surface of copper strips with thickness of 0.4 mm. The structure was fabricated by making ‘V’-grooves in copper strips and perpendicular ‘V’-grooves on the opposite side that intersect the first set of grooves. Micro pores appear at the intersection of these cross-connected grooves, and micro fins appear on the groove fringes. So it can be defined as ‘pore-groove-fin’ structure. The preferable ‘pore-groove-fin’ structure can be obtained under the condition that the tool edge inclination angle (χγ) is 45°, both the major extrusion angle (γo) and the minor extrusion angle (γ 0′ ) are 30°, both the major formation angle (β) and the minor formation angle (β′) are 10°, the ploughing-extrusion depth (fd) is 0.32 mm and the groove pitch is 0.4 mm on surfaces A and B. The formed included angle of groove A is 70°, and the groove depth is 0.3 mm, while the included angle of opposite perpendicular groove B is 20° with the groove depth of 0.35 mm. The obtained fin height is 0.15 mm, the elliptical pore length is 0.2 mm and the width is 0.05 mm. Experiments show that fd has the greatest influence on the formation of micro pores. Bulges appear on the opposite surface B when the ploughing-extrusion depth on surface A (fdA) reaches a critical value. The ploughing-extrusion depth on surface B (fdB) has great influence on the re-growth of fin structure. 相似文献
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微小型毛细泵环热控制系统及其制造技术 总被引:3,自引:0,他引:3
针对当前微电子芯片高热流密度问题,设计一种微小型毛细泵吸环路(Capillary pumped loops,CPL)热控制系统。介绍制造该微小型CPL的方法:采用犁切—挤压成形微沟槽翅结构和刨削成形整体式翅片散热片,毛细吸液芯则采用商用多孔泡沫金属或丝网材料。该微小型CPL系统由蒸发器、冷凝器、蒸汽联管、液体联管以及液体工质组成。蒸发器中含有多尺度多维交错互通微沟槽翅强化沸腾结构,冷凝器为微沟槽翅结构与翅片散热片组成的复合结构,可有效提高系统蒸发冷凝效率。整个系统利用工质蒸发冷凝相变传热,通过毛细泵吸作用和蒸发气体压力保证循环,依靠饱和毛细芯对气体的阻碍作用保证工质的单向流动,无需机械泵和阀控制。 相似文献
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建筑制图中关于投影的深入剖析 总被引:1,自引:1,他引:0
通过阐述投影现象与投影的联系与区别,针对形成投影的三要素,在保持形体与投影面相对位置不变的情况下,分析了投影线的特性,并且分析了平行投影的4个性质以及投影的工程应用,明确了研究投影的实际意义。 相似文献
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