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Under certain growth conditions for systems with a film/substrate lattice misfit, the deposited material is known to aggregate into island-like shapes. We have obtained an analytical expression of the total free energy, which consists of strain energy, surface energy and interfacial energy of a coherent island/substrate system, and the change of equilibrium aspect ratio versus the volume of the island and the misfit of lattices in the system, which provides a broad perspective on island behaviour. These then were used to study the equilibrium shapes of the system. The results show that in order to minimize the total free energy, a coherent island will have a particular height-to-width aspect ratio, called equilibrium aspect ratio, that is a function of the island volume and misfit. The aspect ratio is increased with increasing island volume at a fixed misfit, and with increasing misfit strain between the island and substrate at a fixed island volume. Moreover, the effect of misfit dislocation on the equilibrium shape of the island is also examined. The results obtained are in good agreement with experiment of observations and thus can serve as a basis for interpreting the experiments. 相似文献
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μC/OS-Ⅱ在ARM系列单片机S3C44B0x上的移植 总被引:2,自引:1,他引:1
给出在ARM系列单片机S3C44B0x上移植嵌入式实时操作系统μC/OS-Ⅱ的一种方法,介绍了实时操作系统μC/OS-Ⅱ和S3C44B0x单片机的特点,讨论μC/OS-Ⅱ在S3C44B0x上移植的可能性,并成功地将实时操作系统μC/OS-Ⅱ移植到S3C44B0x上.在移植过程中所做的主要工作就是对μC/OS-Ⅱ源代码中的三个主要文件进行重新配置和修改.在S3C44B0x开发板上成功实现该移植过程,通过测试验证了移植代码的正确性. 相似文献
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比色高温传感器参数分析及其在爆炸场中的应用 总被引:1,自引:0,他引:1
基于比色测温原理,系统分析了中心波长、波长带宽、立体角等因素对仪器响应速度和测温精度的影响,确定了适用于瞬态高温测量的系统参数。提出了基于光电转换系数和工作波长上下极限的比色高温传感器响应计算方法。在优化的标定温度下,用高温黑体炉进行标定实验,通过对标定数据的分析确定了仪器实际工作参数,并对传感器温度响应进行了计算。结果表明用该方法计算得到的响应关系误差在1%以内。利用该比色高温计现场测试了燃料空气爆炸场的瞬态温度响应,得到了爆轰区温度随时间、距离的变化规律。 相似文献
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基于DSP的闭环控制逆变,采用TMS320F2812作为控制器.文章通过对DSP编程产生的PWM和SPWM,以光耦隔离分别来驱动高频逆变桥和工频变换器,同时分析了逆变桥中开关损耗,通过改进算法,提高了转换效率. 相似文献
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