常州市数字化测绘工程及GIS建库概述

数字化地形图和地籍图是城市规划、建设和管理及国土资源管理的重要基础资料．也是开展数字城市和信息化建设的最基础平台。通过对系统总体结构的设计和应用成果介绍，分析了目前基础地理数据生产、管理和应用的现状，介绍了基于GIS的常州市数字化地形图、地籍图测绘工程总体目标及基础地理信息系统总体设计．并概述了整个数字化测绘工程的实施过程和特点。     

高光谱数据在数据库中的高效存储技术研究

通过分析高光谱数据的特点 ,结合数据库系统开发实践 ,提出了高光谱数据集 ,包括图像、光谱、属性等 ,在关系数据库中的存储规范。结合ORACLE数据平台 ,提出了 3种高光谱数据的存储模式 ,并结合应用实例进行对比 ,分析了各自的优缺点以及适用条件。     

Analytic expressions for the velocity sensitivity to the elastic moduli for the most general anisotropic media

For non‐linear kinematic inversion of elastic anisotropy parameters and related investigations of the sensitivity of seismic data, the derivatives of the wavespeed (phase velocity and group velocity) with respect to the individual elastic moduli are required. This paper presents two analytic methods, called the eigenvalue and eigenvector methods, to compute the derivatives of the wavespeeds for wave propagation in a general anisotropic medium, which may be defined by up to 21 density‐normalized elastic moduli. The first method employs a simple and compact form of the eigenvalue (phase velocity) and a general form of the group velocity, and directly yields general expressions of the derivatives for the three wave modes (qP, qS₁, qS₂). The second method applies simple eigenvector solutions of the three wave modes and leads to other general forms of the derivatives. These analytic formulae show that the derivatives are, in general, functions of the 21 elastic moduli as well as the wave propagation direction, and they reflect the sensitivity of the wavespeeds to the individual elastic moduli. Meanwhile, we give results of numerical investigations with some examples for particular simplified forms of anisotropy. They show that the eigenvalue method is suitable for the qP‐, qS₁‐ and qS₂‐wave computations and mitigates the singularity problem for the two quasi‐shear waves. The eigenvector method is preferable to the eigenvalue method for the group velocity and the derivative of the phase velocity because it involves simpler expressions and independent computations, but for the derivative of the group velocity the derivative of the eigenvector is required. Both methods tackle the singularity problem and are applicable to any degree of seismic anisotropy for all three wave modes.     

当前国际水文学科技术领域的研究方向

根据联合国有关机构发布的公报和世界各国近年来的学术研究情况，整理出了近期水文学科在地表水、地下水、水质、水资源系统、大气～土壤～植被、大陆侵蚀、冰雪、遥感技术和示踪技术等领域的热门研究课题，在一定程度上反映了当前国际上水文学科的研究和发展方向，对国内同行有一定的参考价值。     

Migrating pingos in the permafrost region of the Tibetan Plateau, China and their hazard along the Golmud–Lhasa railway

Most pingos in the permafrost region of the high northern Tibetan Plateau form along active fault zones and many change position annually along the zones and thus appear to migrate. The fault zones conduct geothermal heat, which thins permafrost, and control cool to hot springs in the region. They maintain ground-water circulation through broken rock in an open system to supply water for pingo growth during the winter in overlying fluvial and lacustrian deposits. Springs remain after the pingos thaw in the summer. Fault movement, earthquakes and man's activities cause the water pathways supplying pingos to shift and consequently the pingos migrate.

The hazard posed to the new Golmud–Lhasa railway across the plateau by migrating pingos is restricted to active fault zones, but is serious, as these zones are common and generate large earthquakes. Pingos have damaged the highway and the oil pipeline adjacent to the railway since 2001. One caused tilting and breaking of a bridge pier and destroyed a highway bridge across the Chumaerhe fault. Another has already caused minor damage to a new railway bridge. Furthermore, the construction of a bridge pier in the North Wuli fault zone in July–August 2003 created a conduit for a new spring, which created a pingo during the following winter. Measures taken to drain the ground-water via a tunnel worked well and prevented damage before the railway tracks were laid. However, pier vibrations from subsequent train motion disrupted the drain and led to new springs, which may induce further pingo growth beneath the bridge.

The migrating pingos result from active fault movement promoting artesian ground-water circulation and changing water pathways under the seasonal temperature variations in the permafrost region. They pose a serious hazard to railway construction, which, in turn can further disturb the ground-water conduits and affect pingo migration.     

现浇薄壁管桩复合地基非线性有限元分析

现浇薄壁管桩是处理大面积软土地基的一项新技术,目前已在沿海软土地区高速公路建设中得到了一定的应用,但其产生的时间较短,开展的研究相对较少,利用Plaxis岩土工程有限元软件对现浇薄壁管桩（PCC桩）的工作特性、荷载传递规律及其影响因素、加固机理等方面进行了详细的分析,结果表明,桩外壁摩阻力随桩深近乎呈线性分布,桩内壁摩擦力只在桩下端一定长度内有所发挥,桩芯土体具有较好的闭塞效应,研究成果具有较大的指导意义.     

云南个（旧）-冷（墩）公路K22＋336回头湾段边坡治理工程研究

目前，在我国地质灾害防治及道路建设工程中，岩土锚固施工大多采用单一的拉力型锚索工法。一般锚索索体的长效防腐问题没有得到应有的重视。文章对云南省个旧-冷墩公路边坡工程中所采用的压力分散型锚索工法从设计、试验及成功应用等多方面进行了详细介绍。①在一些复杂地形条件下，锚索防护方案有其独特的经济实用性。②在地基承载力较低的软弱地层中，常用的拉力型锚索无法提供防护工程所需的大吨位锚固力。而有多个受力体的压力分散型锚索则因其对锚固段全长范围内地基承载力的充分利用来提供较大吨位的锚固力；③永久锚索防护工程作为一项具有隐蔽性强特点的结构工程，为保证在其报务年限内锚索能够可靠地工作，在设计阶段，锚索体的长效防腐应为不能忽略的主要考虑因素。在该工程中首次应用了新型高强材料——环氧全喷涂无粘结钢绞线作为锚索体的杆材，较好地解决了永久锚固工程中的锚索防腐问题。     

超低频电磁声源非线性动力学建模与分析

电磁声源输出力大、体积小、易于实现超低频输出,在无人反水雷作战中具有显著优势。其动力学行为受到机械回复力和电磁力的耦合作用影响,当施加电流超过坍塌电流,电磁力将超过机械回复力, 就会发生吸和,造成声源的损坏。为准确描述电磁声源非线性动力学特性,预先评估坍塌电流,建立考虑动态漏磁系数的声源非线性动力学模型。通过三维有限元仿真计算动铁芯运动到不同位置处气隙的漏磁系数, 拟合得到动态漏磁系数。根据等效磁路法建立声源的改进电磁力模型,进而建立电磁声源非线性动力学模型。 通过 Runge-Kutta 算法计算得到阶跃激励下声源振动的位移和速度,绘制相平面图。研究稳定与失稳 2 种情况下的相轨迹的动态变化规律,为电磁声源的设计和控制提供理论支撑。