虚拟实体生成技术研究

介绍了虚拟实体的定义、研究内容和一个研究实例，并指出了虚拟实体生成研究对测绘保障的意义。     

星载极化SAR数据模拟

介绍了自行开发的星载极化SAR数据计算机模拟系统，此系统采用的模拟方法遵循了星载极化SAR系统实际运行的情况，按发射脉冲时间序列，分别依次计算各发射脉冲相应的回波数据，与常用的以点目标为基础逐点模拟方法相比，计算效率高，现贴近实际系统，便于模拟各种误差的影响和保持其对所有目标回波影响的一致性和相关性。给出了星载极化SAR数据模拟的实例。     

Past,present and future vegetation-cloud feedbacks in the Amazon Basin

To begin exploring the underlying mechanisms that couple vegetation to cloud formation processes, we derive the lifting condensation level (LCL) to estimate cumulus cloud base height. Using a fully coupled land–ocean–atmosphere general circulation model (HadCM3LC), we investigate Amazonian forest feedbacks on cloud formation over three geological periods; modern-day (a.d. 1970–1990), the last glacial maximum (LGM; 21 kya), and under a future climate scenario (IS92a; a.d. 2070–2090). Results indicate that for both past and future climate scenarios, LCL is higher relative to modern-day. Statistical analyses indicate that the 800 m increase in LCL during the LGM is related primarily to the drier atmosphere promoted by lower tropical sea surface temperatures. In contrast, the predicted 1,000 m increase in LCL in the future scenario is the result of a large increase in surface temperature and reduced vegetation cover.     

山东半岛典型冷涡暴雪个例对流云及风场特征的观测与模拟

利用卫星云图、 多普勒天气雷达资料、 常规观测资料和MM5模式模拟结果, 分析了2005年12月4日典型冷涡造成山东半岛暴雪的云带变化、 对流单体的生成与发展、 低空急流特征及雷达强回波带的变化特征。结果表明： 冬季冷涡携带强冷空气南下, 经过渤海暖湿下垫面后影响山东半岛时, 卫星云图上从渤海到山东半岛可以清楚地分析出造成暴雪的西南-东北向结构特征的横向云带; 雷达图上, 在渤海到山东半岛形成一强降雪回波带, PPI径向速度图上可清楚地分析出暴雪区的低空急流和中尺度对流的低空辐合, 雷达径向速度垂直剖面反映暴雪产生在零速度线附近和低空急流的存在; MM5模式模拟结果显示： 暴雪发生时山东半岛在1.5 km存在低空急流, 水平风的时间-高度垂直剖面反映暴雪发生时干冷空气经过暖湿的渤海海面在700 hPa以下出现暖平流, 垂直上升运动和散度的低层辐合、 高层辐散与雷达图像反映的强降雪回波是相对应的。     

Ground motion prediction equation considering combined dataset of recorded and simulated ground motions

Himalayan region is one of the most active seismic regions in the world and many researchers have highlighted the possibility of great seismic event in the near future due to seismic gap. Seismic hazard analysis and microzonation of highly populated places in the region are mandatory in a regional scale. Region specific Ground Motion Predictive Equation (GMPE) is an important input in the seismic hazard analysis for macro- and micro-zonation studies. Few GMPEs developed in India are based on the recorded data and are applicable for a particular range of magnitudes and distances. This paper focuses on the development of a new GMPE for the Himalayan region considering both the recorded and simulated earthquakes of moment magnitude 5.3–8.7. The Finite Fault simulation model has been used for the ground motion simulation considering region specific seismotectonic parameters from the past earthquakes and source models. Simulated acceleration time histories and response spectra are compared with available records. In the absence of a large number of recorded data, simulations have been performed at unavailable locations by adopting Apparent Stations concept. Earthquakes recorded up to 2007 have been used for the development of new GMPE and earthquakes records after 2007 are used to validate new GMPE. Proposed GMPE matched very well with recorded data and also with other highly ranked GMPEs developed elsewhere and applicable for the region. Comparison of response spectra also have shown good agreement with recorded earthquake data. Quantitative analysis of residuals for the proposed GMPE and region specific GMPEs to predict Nepal–India 2011 earthquake of Mw of 5.7 records values shows that the proposed GMPE predicts Peak ground acceleration and spectral acceleration for entire distance and period range with lower percent residual when compared to exiting region specific GMPEs.     

基于全局弱式无单元法直流电阻率正演模拟

全局弱式无单元法是在有限单元法基础上发展起来的一种数值模拟方法,它采用局部支持域内的节点信息来构造形函数实现局部精确逼近,摆脱了单元,仅依赖于节点信息,具有预处理简单、模拟精度高、灵活性强的特点,适用于复杂地电条件下直流电阻率正演模拟.本文采用RPIM构造直流电阻率全局弱式无单元法形函数,利用RPIM形函数推导了直流电阻率全局弱式无单元法方程.然后,编制了直流电阻率全局弱式无单元法正演模拟Fortran程序,利用该程序对典型的地电模型进行了正演模拟,并将正演结果与基于线性插值的FEM正演结果及解析解进行对比,结果表明采用RPIM形函数的全局弱式无单元法用于直流电阻率正演模拟的正确性及有效性,且在同等条件下,全局弱式无单元法模拟精度高于矩形剖分的FEM,更有利于指导电法勘探的数据解译;利用该程序对复杂地电模型进行了正演模拟,结果表明全局弱式无单元法对复杂地电模型模拟效果良好,适应性强,灵活性高,可任意加密节点提高模拟精度.

     

饱和土体瞬态响应有限元分析

给出基于Biot多孔介质理论分析饱和土体在动载荷作用下瞬态响应的有限元公式,数值计算部分采用本文有限元法分别计算一维饱和土柱在两种不同类型动载荷作用下的瞬态响应,并将数值计算结果与文献中的解析解进行比较,二者结果十分吻合,从而验证本文方法的可行性。     

青岛市黄岛区潮河水源地地下水数值模拟

在分析研究青岛市黄岛区潮河流域水文地质条件基础上,建立了水文地质概念模型和地下水流数值模拟模型,利用地下水水位动态监测资料对模型进行了识别,并预测了三枯一丰一平条件下地下水最大开采量以及水位、降深分布情况。结果表明,模型验证拟合结果较好,地下水最大开采量为2.4万m3/d,地下水开采不会引起地面沉降、海水入侵等问题。     

孤立金属尖端的电晕触发阈值

为了得到金属尖端在发生电晕放电时尖端处的电场强度,该文首先采用实验室实验得到不同高度、不同形状、不同材质的金属尖端发生电晕放电时的环境电场阈值;再采用有限元法计算二维泊松方程,得到尖端处电晕触发阈值,由此得出以下结论:环境电场阈值随金属尖端高度的增大基本呈线性减小趋势,随着尖端越来越尖,环境电场阈值呈先减小后增大的变化趋势;高度、形状对金属物尖端处电晕触发阈值无影响,尖端处电晕阈值为定值;给出尖端处电晕触发阈值为158.75 kV·m-1与空间分辨率的拟合公式,可为今后电晕放电数值模拟中判断电晕放电的起始时刻提供参考。     

石香肠构造研究进展

100多年来，石香肠构造的研究取得了巨大的进展。出现了骨节状石香肠、不对称鱼嘴构造、复合石香肠等新的构造样式。在石香肠构造形成理论研究上，关于断裂石香肠构造形成的理论推导、肿缩石香肠构造形成的流变参数的限制、多层石香肠构造在大地构造研究中的应用、石香肠构造控矿以及石香肠构造流变计的研究已经展开并取得了较大进展。理论研究的深入和应用研究的拓展还需要借助其他学科的研究成果。