基于开源的煤矿地质信息集成平台研究

分析了涉及不同领域、不同历史来源和不同存储载体的矿山地质信息特点,利用开源技术对Web Service架构下地质信息集成平台进行研究,实现了异源、异构、异库的复杂地质信息的数据共享、地图显示以及图形数据处理。     

阿尔泰-阿尔金地学断面地壳结构

根据阿尔泰—阿尔金地学断面的地震纵、横波资料,建立了地壳速度及泊松比结构. 测区的地壳具有明显的三分结构特征,其纵波速度自上而下依次为6.0～6.3km/s、6.3～6.6km/s及6.9～7.0km/s;阿尔泰南缘的地壳最厚,为56km,准噶尔盆地的地壳最薄,为46km,大部分地区的地壳厚度为50km 左右. 准噶尔盆地与天山之间上地幔顶部的纵波速度为7.7～7.8km/s ;阿尔泰南缘及塔里木盆地上地幔顶部的纵波速度较高,为7.9～8.0km/s. 测线南部,包括东天山及塔里木东缘,自地表至30km深处的地壳纵波速度低,泊松比为0.25,表明上地壳主要为石英及花岗质成分;而测线北部(包括阿尔泰及准噶尔盆地)的中、上地壳则呈现较高的泊松比（0.26～0.27）,可能为基性地壳的体现. 厚15～30km的下地壳纵波速度（6.9～7.0km/s）较高,泊松比为0.26～0.28,可能以镁铁质的麻粒岩成分为主. 位于天山及其南侧地壳中部的低速层（VP=5.9km/s, σ=0.25）则可能为晚古生代的构造热事件中的花岗质侵入岩.     

青藏高原那曲地区雷电特征初步分析

通过对2002年夏季青藏高原那曲地区雷暴过程及闪电观测资料的初步分析,发现该地区雷暴电荷结构具有多样性和复杂性,地闪明显偏少. 对高原地闪的一些基本特征参量的统计分析表明,无论正地闪还是负地闪梯级先导前都具有持续时间较长的云内放电过程,地闪以单次回击为主. 与中低纬度地区相比,高原地闪中正地闪比例明显要高,为33髎;负地闪为67髎;正、负地闪回击后常常伴随短时间的连续电流.     

利用GPS监测电离层不均匀结构探讨

利用上海地区GPS综合应用网提供的高时空分辨率的双频GPS观测资料,研究了该区域内一电离层不均匀体的产生、消亡过程.首先,采用Kalman滤波的方法改善双频伪距之差的观测精度,并利用参数估计的方法计算该时段内相应的硬件延迟.再根据电离层单层模型,利用GPS双频观测量、测站位置和GPS精密星历,求出GPS信号穿刺点的坐标和垂直方向电离层的电子含量;然后内插并获取其等值线图.等值线图随时间的变化表明,受等离子体湍流的影响,2003年9月8日北京时间9时40分左右在38°N、118°E左右产生了一电离层不均匀体,其尺度大约在50km左右,生存时间大约为5min.受地球重力场和高空风场的影响,该不均匀体向东北方向扩散.然后,利用大气扩散模型,按扩散方程计算分析了该不均匀体可能发生的电离层层区.理论计算表明,该不均匀体发生在电离层扩展F区,高度在350km左右.     

隔震换能结构体系的能量分析

将换能器安装在隔震结构的隔震层处,由结构和换能装置构成隔震换能结构体系,它既可以将地震输入给结构的部分能量转换成液压能,实现地震能量的转换,又能减小隔震层的水平位移,降低对隔震层的技术要求,降低造价。本文详细研究地震输给隔震换能结构体系的能量在体系各部分的分配,并与普通隔震结构对比,从能量的角度揭示隔震换能体系的换能控制原理。     

气象灾情收集与影响评估工作中存在的若干问题

联系近几年孝感市气象灾情收集与影响评估工作实践,分析了当前气象灾情收集与影响评估工作中存在的主要问题及产生原因,并着重从规范管理机制、完善开放的气象灾情收集网络、建立快速高效的反应体系、加强专业队伍建设和专业技术研究等方面,探讨了解决相关问题的对策。     

Sino‐Kharosthi and Sino‐Brahmi coins from the silk road of western China identified with stylistic and mineralogical evidence

Three coins of the Khotan horse, or Sino‐Kharosthi, style from Xinjiang province of China were recently obtained from a coin dealer. Because the archaeological context of these coins remains unknown, we conducted chemical and stylistic analyses to help determine their authenticity. Energy dispersive X‐ray (EDX) and wavelength dispersive X‐ray (WDX or microprobe) measurements indicate that they are red (pure) copper and bronze coins, with one coin containing 4.2% Ag. Metal content and the presence of secondary minerals formed through weathering indicate that these are authentic ancient coins that were buried in a dry environment. All three coins bear Chinese characters; one shows Kharosthi, and two display Brahmi, a popular language in Khotan from A.D. 260 to 282. This indicates that the Sino‐Brahmi coins were made slightly later than the Sino‐Kharosthi coins, which were made before A.D. 260. These specimens represent the first Sino‐Brahmi coin and 20‐zhu coin ever reported in the literature. © 2011 Wiley Periodicals, Inc.     

An Updated Review of Event Attribution Approaches

There have been considerable high-impact extreme events occurring around the world in the context of climate change. Event attribution studies, which seek to qu...     

A new approach to the determination of the critical slip surfaces of slopes

A new method for the determination of the critical slip surfaces of slopes is proposed in this paper.In this paper,the original critical slip field method is extended in terms of the total residual moment,values of residual work as well as the unbalanced thrust force at the exit point for a given non-circular slip surface.The most critical slip surface with the maximum representative value for a prescribed factor of safety will be optimized and located using the harmony search algorithm.The prescribed factor of safety is modified with certain tiny interval in order to find the critical slip surface where the maximum representative value is zero.The aforementioned approach to the location of the critical slip surface is greatly different from the traditional limit equilibrium procedure.Three typical soil slopes are evaluated by use of the proposed method,and the comparisons with the classical approaches have illustrated the applicability of the proposed method.     

An Effective Control System of Thrust and Moment Modulation for a Dynamically Positioned Vessel

Dynamic positioning (DP) is an operation method whereby the position of a surface vessel is maintained in close proximity to a required position in the horizontal plane through the controlled application of forces and moments generated by purposely installed thrusters. When estimating thrust, this kind of conventional control system often uses many acceleration sensors, velocity sensors, environment sensors, and filters. Usually, these sensors have measured electrical errors. To reduce the number of sensors used and to decrease the measurement errors, this article presents an effective control system for estimating thrust and moment commands, which is based on energy and impulsemomentum principles. Donha and Brinati's example is followed to verify the feasibility of the present control system, which performs semisubmersible platform positioning using an LQG controller, and the results are feasible and economical. A simulated coring vessel marine positioning in southern Taiwan is presented, which can estimate the counterthrust and moment commands, and the complex environmental forces and moments are described. The results can provide a valuable control system for dynamically positioned vessels.