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101.
介绍了列车运行控制系统的基本组成和原理,采用通用ARM芯片S3C2440设计了列车运行控制仿真硬件系统以及包含列车模型的PC端仿真软件.使用串口UART实现下位机控制系统硬件和上位机列车仿真模型软件之间的数据通信.最后,设计了基于滑动模态状态观测器的列车控制算法,并在仿真测试系统中进行了测试. 相似文献
102.
针对手机用户的个性化需求较高及传统方法的进程监控问题, 设计并实现了基于Android 开发平台的手机言行记录系统。该系统通过控制手机通讯录信息、文件加密操作、应用程序监控以及日志监控等方式实时监控分析手机用户的言行记录, 方便用户的自我监控与管理。该方法主要运用Intent 和日志监控实现软件监控功能,通过类FileEncrpter 对文件系统加密, 对录音加密则使用流加密, 运用MediaRecord 类和ACC(Advanced AudioCoding)编码实现音频录制。实验结果表明, 该系统达到了较为理想的实验效果, 证明了该系统的可行性。 相似文献
103.
端面磨损对U型槽动压机械密封性能的影响 总被引:2,自引:0,他引:2
以核主泵所用U型槽动压密封环为对象,研究了密封端面因介质中微粒所引起的磨损问题.结果表明:端面动压槽根部产生的初期磨损将造成刚度和泄漏率增加,且随着磨痕数量的增加,泄漏率呈线性增加;当磨痕贯穿密封坝而使U型槽根部与端面低压侧短路时,将会造成泄漏率的阶跃上升和刚度急剧下降.在实际使用的过程中,多个U型槽将会同时出现磨痕,当一处磨痕贯穿密封坝时,将造成大量介质泄漏,且磨痕越深,其泄漏率越大,最终导致密封失效. 相似文献
104.
针对广义最小二乘算法在WGS-84坐标系中存在收敛速度慢及收敛性能不稳定的问题,提出了一种改进的广义最小二乘算法.该算法以收敛步数作为最小二乘算法中的量测精度加权因子,使得量测精度随着步数的变化而变化,从而实现了收敛步数的减少和收敛之后稳定性的改善,提高了目标跟踪定位的性能.仿真结果表明,改进的广义最小二乘算法优于广义最小二乘算法,进一步验证了该算法的有效性. 相似文献
105.
Contrasting patterns of early twenty-first-century glacier mass change in the Himalayas 总被引:9,自引:0,他引:9
Glaciers are among the best indicators of terrestrial climate variability, contribute importantly to water resources in many mountainous regions and are a major contributor to global sea level rise. In the Hindu Kush-Karakoram-Himalaya region (HKKH), a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance. There is, however, indirect evidence of a complex pattern of glacial responses in reaction to heterogeneous climate change signals. Here we use satellite laser altimetry and a global elevation model to show widespread glacier wastage in the eastern, central and south-western parts of the HKKH during 2003-08. Maximal regional thinning rates were 0.66?±?0.09 metres per year in the Jammu-Kashmir region. Conversely, in the Karakoram, glaciers thinned only slightly by a few centimetres per year. Contrary to expectations, regionally averaged thinning rates under debris-mantled ice were similar to those of clean ice despite insulation by debris covers. The 2003-08 specific mass balance for our entire HKKH study region was -0.21?±?0.05?m?yr(-1) water equivalent, significantly less negative than the estimated global average for glaciers and ice caps. This difference is mainly an effect of the balanced glacier mass budget in the Karakoram. The HKKH sea level contribution amounts to one per cent of the present-day sea level rise. Our 2003-08 mass budget of -12.8?±?3.5 gigatonnes (Gt) per year is more negative than recent satellite-gravimetry-based estimates of -5?±?3?Gt?yr(-1) over 2003-10 (ref. 12). For the mountain catchments of the Indus and Ganges basins, the glacier imbalance contributed about 3.5% and about 2.0%, respectively, to the annual average river discharge, and up to 10% for the Upper Indus basin. 相似文献
106.
在套管射孔压裂井中,存在影响井生产动态的裂缝伤害:瓶颈裂缝和压裂液滤失形成的滤失带伤害。运用分析方法研究了上述伤害对井产能的影响。分析结果表明两种类型的裂缝伤害都会降低压裂井产能,与滤失带伤害相比,瓶颈裂缝大幅度地降低了井产能,最大降幅达7倍。虽然压裂液滤失对井产能的影响没有瓶颈裂缝那么大,但也降低多一半。在实际施工中,应采用各种措施消除瓶颈裂缝和减小压裂液滤失。 相似文献
107.
Analysis of a RanGTP-regulated gradient in mitotic somatic cells 总被引:1,自引:0,他引:1
The RanGTPase cycle provides directionality to nucleocytoplasmic transport, regulating interactions between cargoes and nuclear transport receptors of the importin-beta family. The Ran-importin-beta system also functions in mitotic spindle assembly and nuclear pore and nuclear envelope formation. The common principle underlying these diverse functions throughout the cell cycle is thought to be anisotropy of the distribution of RanGTP (the RanGTP gradient), driven by the chromatin-associated guanine nucleotide exchange factor RCC1 (refs 1, 4, 5). However, the existence and function of a RanGTP gradient during mitosis in cells is unclear. Here we examine the Ran-importin-beta system in cells by conventional and fluorescence lifetime microscopy using a biosensor, termed Rango, that increases its fluorescence resonance energy transfer signal when released from importin-beta by RanGTP. Rango is predominantly free in mitotic cells, but is further liberated around mitotic chromatin. In vitro experiments and modelling show that this localized increase of free cargoes corresponds to changes in RanGTP concentration sufficient to stabilize microtubules in extracts. In cells, the Ran-importin-beta-cargo gradient kinetically promotes spindle formation but is largely dispensable once the spindle has been established. Consistent with previous reports, we observe that the Ran system also affects spindle pole formation and chromosome congression in vivo. Our results demonstrate that conserved Ran-regulated pathways are involved in multiple, parallel processes required for spindle function, but that their relative contribution differs in chromatin- versus centrosome/kinetochore-driven spindle assembly systems. 相似文献
108.
钠粘土与AM单体共混,在130℃下与引发剂和交联剂反应生成了共混胶。该共混胶体系中含钠土6%,单体AM 6%~7%,引发剂Y 100~200mg/L,交联剂J 1%~1.5%。钠土的加入,延缓了成胶时间,提高了热稳定性。该共混胶强度高,封堵能力强,高温堵水应用前景良好。 相似文献
109.
针对屏蔽电动机定转子环形流道内转子转动对其摩擦因子的影响作定量分析.搭建缩尺实验台,实验分析了不同转子转速下定转子间的压力分布规律.实验结果表明:转速的升高会引起压降增大,间隙环流的摩擦因子需要在经验公式上进行修正,分析拟合数据得到了修正系数与切向、轴向雷诺数比值的映射关系,从而推导出了环形流道内考虑周向流动下摩擦因子的修正公式.为了验证该公式的准确性与普遍性,利用计算流体动力学(CFD)软件对缩尺实验台与主泵屏蔽电动机定转子间的流场分别进行仿真,对比数值仿真与该修正公式所求得的摩擦因子,结果表明偏差在合理范围内. 相似文献
110.
云模型是在传统模糊数学和概率统计的基础上提出的定性、定量转换模型。为了建立油气藏与圈闭面积、圈闭闭合幅度、油气运移通道、地层孔隙度、烃源生油与圈闭形成时间、空间匹配性等因素的定性定量关系,传统的多域信息评价方法多采用因素硬化值构建定性定量关系模型,这很大程度受制于专家的知识和经验。结合云模型和灰关联分析,考虑油气圈闭评价因素的模糊性、随机性和小样本不确定性,实现圈闭多域信息的定性与定量间的转换,提出了一种油气圈闭多域信息评价新方法。对中国西北顺托果勒某地区提取的圈闭进行评价,分别划分出了Ⅰ、Ⅱ和Ⅲ类圈闭,其中Ⅰ类圈闭占圈闭总数的37.5%;Ⅱ类圈闭占圈闭总数的37.5%;Ⅲ类圈闭占圈闭总数的25%,与实际开发评价结果吻合。 相似文献