利用球冠谐分析方法提取不同波长重力场异常

介绍球冠谐分析方法在重力场研究中的基本理论和计算方法。探讨了球冠谐系数与波长的关系，以及利用球冠谐分析方法提取不同波长的重量场力场异常，进而研究深部地壳结构的问题，最后给出一个实例。     

圆洞弹性随机位移场的拟解析表达

研究弹性随机介质中圆形洞室的随机位移场的解析原理，并给出了无衬砌圆洞随机位移场的拟解析式及其统计特征。可作为随机场数值计算方法的参考算例。     

多尺度CB形态学及其在线划图像噪声清除中的应用

介绍了基于轮廓结构元的形态学（简称CB形态学）的概念及其性质,讨论了CB形态运算的快速实现。由于CB形态学处理的对象不是基于目标的形状,而是基于目标的延伸度,因此它可以用来处理线划图像。在本文中,利用CB形态学的这一特性消除线划图像上的噪声,获得了满意的结果。     

GOCE Quick-Look Gravity Solution: Application of the Semianalytic Approach in the Case of Data Gaps and Non-Repeat Orbits

The satellite mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer), the first Core Mission of the Earth Explorer Programme funded by ESA (European Space Agency), is dedicated to the precise modelling of the Earth's gravity field, with its launch planned for 2006. The mathematical models for parameterizing the Earth's gravity field are based on a series expansion into spherical harmonics, yielding a huge number of unknown coefficients. Their computation leads to the solution of very large normal equation systems. An efficient way to handle these equation systems is the so-called semianalytic or lumped coefficients approach, which theoretically requires an uninterrupted, continuous time series of observations, recorded along an exact circular repeat orbit. In this paper the consequences of violating these conditions are analyzed. The effects of an interrupted observation stream onto the estimated spherical harmonic coefficients are demonstrated, and an iterative strategy, which reduces the negative influence depending on the characteristics of the data gaps, is proposed. Additionally, the impact of an imperfectly closing orbit (non-repeat orbit) on the gravity field model is analyzed, and a strategy to minimize the corresponding errors is presented. The applicability of the semianalytic approach also to a joint inversion of satellite-to-satellite tracking data in high-low mode (hl-SST) and satellite gravity gradiometry (SGG) observations is demonstrated, where the analysis of the former component is based on the energy conservation law. Several realistic case studies prove that the semianalytic approach is a feasible tool to generate quick-look gravity solutions, i.e. fast coefficient estimates using only partial data sets. This quick-look analysis shall be able to detect potential distortions of statistical significance (e.g. systematic errors) in the input data, and to give a fast feedback to the GOCE mission control.     

Map projection errors in the Weber problem

 When demand points are given as a planar map where projection method is explicitly stated, we usually know the latitudes and longitudes of these points from the map. Then we can solve the Weber problem on the globe, and we do not suffer from errors. This paper analyses how cylindrical projections cause distortion in the Weber problem when demands are distributed on the Northern Hemisphere. First, we demonstrate that planar solutions are always located south of the spherical solution if the Mercator projection, the equirectangular projections with standard parallels near the demands, or the equal-area projection with the same characteristic is chosen. Second, we verify that this geographical tendency is inclined to hold when the demand points, are distributed symmetrically, widely or toward the north. Received: 15 August 2001 / Accepted: 20 April 2002 This paper was partially written while the first author was visiting the Department of Geography at the Catholic University of Louvain, Louvain-la-Neuve, Belgium [1993–1994]. He is grateful for the hospitality of this department. An earlier version of this paper was presented in 1994 at the Seventh Meeting of the European Operational Research Working Group on Locational Analysis in Brussels, and in 1996 at the Fifth World Congress of the Regional Science Association International in Tokyo. The authors would also like to thank the participants as well as three anonymous referees for their constructive comments.     

爆炸应力波近似处理的分析与研究

通过弹性球面波的势函数求得了爆炸应力波BSW模型中弹性球面波的径向应力、质点振速等的显式解析解，并据此通过数值模拟得出实际计算中将球面波按平面波近似处理的误差及该误差随爆源距离，泊松比等的变化而产生变化的曲线。分析结果表明：距离是影响误差的决定性因素；在此条件下，当距离大于2－5m时，弹性球面波即可近似按平面波处理，其误差不超过5％，当距离小于此范围时，误差较大。     

卫星重力梯度数据的模拟研究

推导了运用地球重力场模型计算单点、格网点以及格网平均的扰动重力梯度复组合分量的公式;提出了广义球谐函数及其定积分的新算法,并利用EGM96地球重力场模型试算了全球地区卫星轨道面上的重力梯度分量的格网平均观测值;通过对角线分量满足Laplace方程的精度,验证了该算法的有效性和实用性。     

自动连续称重式集沙仪设计及野外应用

集沙仪是定量监测风沙活动的重要工具。设计了一种自动连续称重式集沙仪,可以根据试验需要采集不同高度沙样,每分钟收集一次质量数据,实现高频连续集沙。试验结果显示,自动连续称重式集沙仪在15、30、60 cm高度的集沙量满足随高度增加呈指数减少的规律;在15 cm高度,风速与输沙通量呈指数函数关系(y=6E-05·e0.8417x,R2=0.6042),随集沙高度升高输沙通量与风速相关性减弱。自动连续称重式集沙仪与新型平口式集沙仪所测的输沙通量具有很好的一致性(y=0.8119x+0.2645,R2=0.7481)。自动连续称重式集沙仪虽然在稳固性方面需要改良,但能够很好地捕捉高度在15 cm以下沙物质的输移信息,野外应用效果良好,是一种适合野外高精度风沙活动自动监测的新型测量工具。     

小高层住宅结构方案--大开洞剪力墙与异型柱框剪结构对比分析

通过对某小区小高层住宅2种结构方案的综合讨论,分析了小高层住宅的合理结构型式,提出了设计建议可供工程设计参考。异型柱框架-剪力墙结构框架柱布置灵活、隐蔽性好,但其柱截面不规则、计算理论不成熟、抗震能力较差、构造措施不理想、而且建筑自振周期长,侧向位移大,难以用于较高的高层住宅和抗震烈度较高的地区;大开洞剪力墙结构受力明确、计算理论成熟,又有较为精确的计算程序,而且墙厚可以在规范允许的范围内减薄,从而进一步降低了工程造价。通过2种方案比较,认为大开洞剪力墙体系与异型柱框剪结构相比,配筋总量基本接近,但其侧移较小,具有较好的延性,可应用于小高层住宅和地震烈度较高地区并可取得显著经济效益。     

2003年中国及邻区地磁场模型的计算与分析

根据2003年中国地区的135个测点和35个台站的地磁数据, 建立了2003年中国及邻区地磁场泰勒多项式模型和球冠谐模型. 在模型计算过程中, 细致地分析了模型的截断阶数和边界约束对模型计算的影响. 结果表明, 所使用的地磁观测资料是准确可靠的, 模型截断阶数的选取是合理的. 本文所建立的中国区域地磁场球冠谐模型与泰勒多项式模型具有良好的一致性.