排序方式: 共有39条查询结果,搜索用时 15 毫秒
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反应气体配比对C/SiC复合材料ICVI工艺沉积性能的影响 总被引:2,自引:0,他引:2
研究了均热法化学气相渗透工艺过程中反应气体浓度、配比及流动对沉积物和复合材料性能的影响,提出了一种简单反应气体在线监控法。XRD分析结果表明,当H2/MTS摩尔比在2-5之间时,可沉积出纯净均匀的碳化硅基体;而H2/MTS摩尔比小于1时,沉积物中含有大量自由碳。SEM分析表明,甲基三氯硅烷的浓度对沉积速率和沉积深度影响很大,随着甲基三氯硅烷的浓度减小,沉积深度增大,但甲基三氯硅烷的浓度减小引起沉积速率下降,沉积周期延长,确保护内反应气体流动畅通,可提高沉积的均匀性和沉积速率。 相似文献
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VxWorks下设备驱动技术研究 总被引:3,自引:0,他引:3
讨论了实时多任务操作系统VxWorks下驱动程序原理及实现.在深入分析VxWorks操作系统的I/O系统及驱动程序调用过程的基础上,介绍了PCI/ISA设备驱动的实现,重点给出了驱动程序实现的关键代码,同时对提高驱动程序的性能进行了讨论. 相似文献
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The main production process of species occurring in the coma of comets is the photodestruction of molecules initially present
in the nucleus ices and non-refractory grains or trapped inside the nucleus "material". Grains can also be a source of molecules
in the coma. Chemical reactions may occur between coma species. Consequently, although chances that an abundant coma species
has not been detected are now small, the coma composition is certainly quite different from that of the nucleus. Except for
the molecules released directly at the nucleus surface, all coma species are produced in an "extended region" or come from
"a distributed source". Since the recent literature is rich in reports on observations of molecules and species possibly not
initially present in the comet ices or not released at the nucleus, a general discussion of how coma species are stored, processed
or produced is presented, based mostly on observational results. What is at stake is the proper modeling of the coma structure,
hence an accurate derivation of the nucleus composition from coma observations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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基于Vxworks嵌入式系统的多串口扩展卡设备驱动程序设计 总被引:1,自引:0,他引:1
本文分析Vxworks操作系统下设备驱动程序在系统中的层次结构和串口设备驱动程序的运行机制,并结合对多串口卡的驱动程序介绍了串口设备驱动程序开发的基本思路。 相似文献
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