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131.
132.
将光线踪迹/节点分析法拓展,用以计算具有基底,多层半透明非灰介质的辐射与导热瞬态耦合换热,分析了吸收-散射性非灰复合层的态传热特性,考察了不透明界面(表面有积灰),半透明界面(表面没有积灰)的表面辐射特性以及复杂换热边界条件,采用具有多个波段的谱带模型模拟高散射性氧化锆的辐射特性,与采用双热流结合林函数法的计算结果比较表明,本文的计算结果可靠,精度高,为工程设计提供了参考依据。 相似文献
133.
Highly precise 40Ar-39Ar dating results demonstrate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7–124.3 Ma,
and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rocks have relatively high (87Sr÷86Sr)i ratios (0.708715–0.711418) and distinctly negative εnd values (−11.47–−17.54), and are enriched in radiogenic lead (206Pb÷204Pb=17.341−17.622, 207Pb÷204Pb=15.525−15.538, 208Pb÷204Pb = 37.563−37.684). Similarly, the lamprophyres also have quite low εnd values (−11.57–−19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are
very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings,
and extensive comparisons of the Sr, Nd isotopic compositions with that of the related simultaneous rocks, it is concluded
that the potash-rich volcanic rocks and lamprophyres in western Shandong Province were most possibly derived from the partial
melting of enriched mantle which was caused by source contamination and metasomatism of subducted continental crustal materials. 相似文献
134.
设计了一种焊接用触觉传感器 ,该传感器通过摆动将焊缝位置采集出来 ,通过计算机进行信号分析来判断焊枪是否偏离焊缝 ,以便及时纠正焊枪位置 ,保证焊接质量。 相似文献
135.
追踪问题是数学建模中的一类经典问题,本文在该问题的微分方程模型的基础上构建了相应的Simulink模型,然后利用Matlab软件进行了数值仿真,利用动画模拟了追踪问题的全过程。 相似文献
136.
提出了一种新的跟踪、重演方法,采用插桩技术在源程序中插入控制程序执行的同步操作,使特定的同步事件序列再现.此方法将同步控制逻辑分散在源程序中,很好地适应了基于消息传递并行系统的运行特征,提高了重演执行的性能,并且不存在缓冲区溢出问题. 相似文献
137.
应用傅立叶综合方法和波束跟踪理论,研究了分层介质中运动声源和接收器的宽带脉冲声传播,根据运动声源和接收器声传播的简正波理论,导出了基于波束跟踪方法的运动声源和接收器宽带脉冲声传播表达式.结合实例计算分析了宽带脉冲声传播的特点,并与宽带简正波的计算结果进行了比较,二者符合较好,证明了这一仿真模型的有效性. 相似文献
138.
《科学通报(英文版)》2008,(9)
Wind erosion is one of the major factors of land degradation in the typical steppe region, northern Mongolian Plateau. Using 137Cs tracing technique, we estimated the wind erosion rates of different pastures and abandoned farmland at Bayannur and Karakorum in Mongolia. The pastures and cutting grassland at Bayannur were slightly eroded by wind, with the rates of 64.58-169.07 t·km?2·a?1. The abandoned farmland in Karakorum, however, was strongly eroded by wind, with annual surface soil loss of 4.05 mm·a?1, and wind erosion rates up to 6723.06 t·km?2·a?1. The total loss of surface soil due to wind erosion has been 17.4 cm since the cultivation of the steppe land in the 1960s. The wind ero- sion rate at the abandoned farmland was much higher than that at the typical steppe sites, showing that the cultivation led to serious wind erosion in the typical steppe region, northern Mongolian Plateau. By contrast, traditional livestock grazing resulted in less disturbance to the surface soil, and did not in- duce to devastating wind erosion, which plays an important role in maintaining the stability of the steppe ecosystem in the northern Mongolian Plateau. 相似文献
139.
Estimation of wind erosion rates by using ~(137)Cs tracing technique:A case study in Tariat-Xilin Gol transect, Mongolian Plateau 总被引:3,自引:0,他引:3
《科学通报(英文版)》2008,(5)
Wind erosion is one of the major environmental problems in semi-arid and arid regions. Here we es- tablished the Tariat-Xilin Gol transect from northwest to southeast across the Mongolian Plateau, and selected seven sampling sites along the transect. We then estimated the soil wind erosion rates by using the ~(137)Cs tracing technique and examined their spatial dynamics. Our results showed that the ~(137)Cs inventories of sampling sites ranged from 265.63±44.91 to 1279.54±166.53 Bq·m~(-2), and the wind erosion rates varied from 64.58 to 419.63 t·km~(-2)·a~(-1) accordingly. In the Mongolia section of the transect (from Tariat to Sainshand), the wind erosion rate increased gradually with vegetation type and climatic regimes; the wind erosion process was controlled by physical factors such as annual precipitation and vegetation coverage, etc., and the impact of human activities was negligible. While in the China section of the transect (Inner Mongolia), the wind erosion rates of Xilin Hot and Zhengxiangbai Banner were thrice as much as those of Bayannur of Mongolia, although these three sites were all dominated by typical steppe. Besides the physical factors, higher population density and livestock carrying level should be responsible for the higher wind erosion rates in these two regions of Inner Mongolia. 相似文献
140.
三维地理环境下电磁波场强预测并行计算研究 总被引:3,自引:0,他引:3
在基于3DCM的电磁波空间专题信息的定量分析研究中,电磁波场强预测是基础性工作.目前射线跟踪模型是比较有效的定量预测模型.针对电磁波场强射线跟踪预测模型计算量大的瓶颈问题,研究了基于.NETRemoting的射线跟踪并行计算解决方案,实验证明该计算方案能缩短计算周期,从而使得电磁波场强预测射线跟踪方法走向实用. 相似文献