轮胎温度场的有限元分析

综合考虑轮胎胶料滞后热源和摩擦热源的作用,对轮胎非稳态温度场进行计算机仿真,分析轮胎从启动到稳态行驶阶段的温度场的变化。探索引起温度场变化的主要原因,对于指导轮胎的结构的优化设计有一定的指导意义。     

安宁河裂谷的“活化”

安宁河裂谷位于"攀西裂谷"的中轴部位,近期研究发现,裂谷区有显著的地壳引张作用,存在地幔隆起与热对流。通过野外实地调查,结合地球物理、断裂、沉积、地震、地应力和地形变等资料,认为安宁河裂谷区现在正处于明显的构造活化状态。这种活化受上地壳塑性流动产生的水平挤压和地幔隆起产生的应力张量的共同作用。据此提出一个新的裂谷活化地壳力源模型,认为在研究区特定的地球动力环境下,以安宁河裂谷为中心,再现岩浆活动和地壳裂陷并非不可能。     

大地电磁反演中改进的自适应正则化因子选取研究

通过建立大地电磁(MT)层状地电模型,利用共轭梯度法求解反问题,在给定不同初始模型的条件下对多种正则化因子选取方法进行了计算比较,分析了各种方法的特点和使用条件.结果表明,自适应正则化算法的效果与传统的定值方法如L曲线法相近,但反演过程远比传统方法便捷.为了解决反演依赖于初始模型的局限并增强解的稳定性,基于多种自适应正则化方案的对比分析,提出了改进的自适应正则化方案,选取数据拟合泛函与模型稳定泛函较大的比值为正则化因子的初始值,并提出相应的调整方案自动控制正则化因子衰减.模型试验表明,该方法对初始模型的依赖性低于其他几种自适应的算法,反演结果的稳定性较强,可以进一步提高正则化反演的效率.     

水库倾斜地形污染混合区的三维解析计算方法

在恒定时间连续点源条件下,从移流扩散方程的简化三维解析解出发,对水库倾斜岸坡地形污染混合区的三维解析计算方法进行了探讨和理论求解,推导了污染混合区长度、最大宽度、最大深度、相应纵坐标和面积以及最大允许污染负荷量的解析计算公式,进行了污染混合区解析计算公式的分析与讨论。结果表明,水库倾斜岸坡地形污染混合区解析计算公式与等标污染负荷、流速、角域映射系数以及岸边混合扩散特性等因素有关,可以作为水库排污口污染混合区允许范围的计算依据,也可以根据水质目标浓度与背景浓度之差,以及污染混合区允许长度或面积或宽度计算最大允许污染负荷量。给出了非保守物质污染混合区长度的计算公式和忽略反应降解作用按保守物质处理的条件:降解数≤0.054。     

开源信息在突发事件应急管理中的应用

互联网上的开源信息具有很高的潜在应用价值,对其进行开发利用可以提高突发事件中应急管理的效率。阐述了开源信息处理的三个重要环节,讨论了突发应急事件中开源信息处理的特殊要求与主要方法,最后以"天网工程"在四川汶川地震中的作用进行了案例分析,主要侧重于监测和分析地震中网络群体对事件的关注及各类情绪的变化特征。     

Relationship between the atmospheric heat source over Tibetan Plateau and the heat source and general circulation over East Asia

On the basis of NCEP/NCAR version I daily reanalysis data from 1971 to 2000 and by the methods of inverse calculation, correlation analysis and comparative analysis, the influences of atmospheric heat source （AHS） over the Tibetan Plateau on the large-scale AHS and the general circulation in summer are studied in this paper. The results show that AHS over the plateau in summer may trigger a heat source wavetrain propagating northeastward along the coast from the East Asian continent and West Pacific to Bering Strait-Arctic or even North America. In addition, if AHS over the eastern plateau is intense, South Asian High moves to southeast and West Pacific subtropical high moves to southwest; on the contrary, if AHS over the eastern plateau is weak, South Asian High moves to northwest and West Pacific subtropical high moves to northeast. Therefore, South Asian High and West Pacific subtropical high move in the horizontally-opposite directions in terms of interannual variation, for which AHS over the eastern plateau seems to be thermodynamically responsible.     

Sea surface temperature and terrestrial biomarker records of the last 260 ka of core MD05-2904 from the northern South China Sea

This paper reports high-resolution biomarker records of the last 260 ka for core MD05-2904 from the northern South China Sea （SCS）. The sea surface temperature （SST） record using the U37^k＇, index reveals a minimum of 21.5℃（MIS 2） and a maximum of 28.3℃（MIS 5.5）, for a temperature difference of almost 7℃, and provides the longest high-resolution U37^k＇ SST record in northern SCS. The content of odd-number long chain n-alkanes and several n-alkanes indexes such as the CPI, ACL and the C31/C27 ratio, all reveal generally higher values during the glacials and lower values during the interglaclals. Terrestrial input as Indicated by n-alkane content was mostly controlled by sea-level changes： During the glacials, lower sea-level exposed the continental shelf to enable rivers to transport more terrestrial materials to the slope; and the situation reverses during the interglacials. The n-alkane indexes changes reveal more n-alkanes from contemporary vegetation during glacials as a result of the proximity of the core site to the source region, while the increases in ACL and C81/C27 ratio during glaclals indicate a change to more grassy vegetation. However, the highest values for CPI, ACL and the C81/C27 ratio all occurred during late MIS 3, and it was suggested that this period was characterized by a strong summer monsoon-dominated humid climate which resulted in a denser vegetation for the exposed continental shelf region.     

Analysis of the carbon source for diamond crystal growth

The lattice constants of diamond and graphite at high pressure and high temperature （HPHT） were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules （EET）, the valence electron structures （VESs） of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng （TFDC）. It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.     

带非局部源和吸收项的退化奇异抛物方程的爆破

考虑了带齐次Dirichlet边界条件的含有吸收项的非局部退化奇异抛物方程xmut-(xrux)x=∫a0updx-kuq解的爆破性质.使用特征函数和上下解技巧,得到了正解整体存在性与有限时刻爆破的充分条件.在一定条件下,证明了爆破解的爆破集是整个区域.     

磁聚焦电导率成像系统的阵列线圈驱动电路设计实现

利用晶体振荡器设计稳定度很高的信号源,其输出由可编程放大器调节后,经过功率放大电路输出至线圈阵列,实现了对三种不同结构和性能的阵列线圈的驱动, 使线圈阵列达到很好的磁场聚焦效果.