盛夏强降水的多普勒雷达回波特征的初步分析     

李进忠  李霞  张燕 《沙漠与绿洲气象(新疆气象)》2003,26(2):24-26,F003

使用红外云图、多普勒雷达回波的强度场、速度场及VAD产品，对2002年7月24日夜间至25日凌晨的中天山及其北部地区的强降水天气过程进行了分析、诊断，得出对降水过程不同时段临近预报有指导意义的结论和指标。  相似文献   

Trimble 5700卫星定位仪在油田井位勘定中的应用     

刘霞 《全球定位系统》2003,28(3):37-41

本文主要介绍了Trimble 5700测地型卫星定位仪的主要性能、在油田井位勘定中的应用及其软件数据处理统计分析。  相似文献   

Analysis of tectonic settings of global superlarge porphyry copper deposits     

Xia Bin  Chen Genwen  Wang He 《中国科学D辑(英文版)》2003,46(1):110-122

About three quarters of superlarge porphyry copper deposits throughout the world occur along the eastern Pacific basin rim, most of which were formed during the Mesozoic-Cenozoic. Porphyry copper deposits often occur in the upper parts of a subduction zone and in a within-plate orogenic belt. Some porphyry copper deposits are inconsistent with plate subduction with respect to their formation time, and most of them in the world are associated with tensional environment. Metallogenic porphyries originated from the mantle, and the involvement of the lower-crust or oceanic crust materials have played an important role. Based on the geochemical characteristics and tectonic settings of the ore-bearing porphyries in the Gandise and Yulong metallogenic zones, it is proposed that delamination may be the important mechanism of formation of porphyry copper deposits.  相似文献   

头颅CT造影增强扫描技术临床应用价值     

卢霞  胡兵 《CT理论与应用研究》2003,12(1):36-38

目的 探讨头颅CT增强造影扫描技术在临床应用价值。材料与方法 着重分析48例病例在CT造影增强扫描后的影像表现。结果 病灶均匀一致性强化8袋子例，环状强化9例，点状强化7例，结节状强化12例，不规则强化7例，强化不明显5例，脑膜或小脑幕强化结构清晰38例。结论 头颅CT增强造影扫描能够提高病变的密度分辨力，有利于明确病变的定位和定性，为临床提供更多的重要信息。  相似文献   

新沂台地电阻率整点值的远大震前驱波变化   总被引：3，自引：1，他引：3  

冯志生  杨从杰  梅卫萍  张秀霞  夏忠 《地震地磁观测与研究》2003,24(4):9-13

介绍江苏新沂台地电阻率整点值观测资料中的一种新变化——远大震前驱波，并简单分析了产生这种变化的机理。这一变化对预测远大震具有前兆意义，值得进一步深入研究。  相似文献   

Multichannel analysis of surface wave method with the autojuggie   总被引：2，自引：0，他引：2  

Gang Tian  Don W. Steeples  Jianghai Xia  Richard D. Miller  Kyle T. Spikes  Matthew D. Ralston 《Soil Dynamics and Earthquake Engineering》2003,23(3):61-65

The shear (S)-wave velocity of near-surface materials and its effect on seismic-wave propagation are of fundamental interest in many engineering, environmental, and groundwater studies. The multichannel analysis of surface wave (MASW) method provides a robust, efficient, and accurate tool to observe near-surface S-wave velocity. A recently developed device used to place large numbers of closely spaced geophones simultaneously and automatically (the ‘autojuggie’) is shown here to be applicable to the collection of MASW data. In order to demonstrate the use of the autojuggie in the MASW method, we compared high-frequency surface-wave data acquired from conventionally planted geophones (control line) to data collected in parallel with the automatically planted geophones attached to steel bars (test line). The results demonstrate that the autojuggie can be applied in the MASW method. Implementation of the autojuggie in very shallow MASW surveys could drastically reduce the time required and costs incurred in such surveys.  相似文献   

Experimental Research on the Load／Unload Response Ratio （LURR） Theory     

Yu Huaizhong  Yin Xiangchu  Liang Naigang  Xia Mengfen  Li Min  Xu Zhaoyong  Peng Keyin  Victor Kukshenko  Wu Zhishen  Qi Li  Surguei Elizarov 《中国地震研究》2003,17(3):227-235

Implementing acoustic emission experiments with large rock samples, LURR (Load/Unload Response Ratio) theory was studied. The loading conditions in the experiments were designed to simulate the complicated loading process of underground rocks. The damages emerging inside the rock samples were recorded by the acoustic emission technique during the loading process. The experimental results were consistent with prediction by LURR theory. Integrating the changing processes of LURR value Y and the location process of acoustic emission events showed agreement between the variation of LURR value Y and the damage evolution inside the rocks. Furthermore, the high value of Y emerged before the complete breakdown of materials. Therefore, the damage evolution of rock specimen can be quantitatively analyzed with LURR theory, thus the failure of the rock materials and the earthquake occurrence may be predicted. The experimental results gave a further verification of LURR theory.  相似文献   

我国北方4kaB.P.前后异常洪水事件的初步研究   总被引：16，自引：0，他引：16       下载免费PDF全文

夏正楷  杨晓燕 《第四纪研究》2003,23(6):667-674

史前异常洪水事件的初步调查表明,4kaB.P.前后是我国北方异常洪水多发的时期,黄河流域、淮河流域和海河流域在这一时期普遍出现不同形式的史前异常洪水事件.异常洪水事件的出现与当时的降温事件有密切的关系,气候变冷引发的相对湿度加大和降雨量增多可能是造成这次异常洪水事件的主要原因.出现于华夏文明诞生前夕的史前异常洪水事件对华夏文明的演进势必会产生重大影响,在黄河上游的山间盆地和下游的黄淮海平原,异常洪水给人类生存环境带来严重的破坏,导致这些地区早期文明的衰落;而位于我国地貌大势二级阶梯与一级阶梯之间的中原地区,尽管洪水也给人类生存环境造成严重的威胁,但它并没有导致早期文明的衰落,恰恰相反,先民们利用有利的地貌条件,通过与洪水的争斗,促进了文化的发展和华夏文明的诞生.  相似文献   

综合工程物探在上海地铁四号线抢险工程中的应用   总被引：3，自引：0，他引：3  

王治华  夏学礼 《上海国土资源》2003,(3):33-40

在上海地铁四号线抢险工程中,综合工程物探快速、准确地圈定了受地面沉降影响,周边土体的扰动范围及深度,并对江底隧道的状况进行了调查。文章介绍了用地质雷达、高分辨率SH波浅层反射波法、瞬态瑞雷面波法勘探及水上高密度多波列地震影像法等综合工程物探方法在该工程中的应用前提及效果。  相似文献   

哈尔滨高等级公路路基沉降监测反分析   总被引：1，自引：0，他引：1  

夏彩虹  佴磊 《世界地质》2003,22(3):298-302

本文应用双曲线配合法对哈尔滨高等级公路路基实测沉降进行了分析，推算了地基的最终沉降量，并由此用太沙基方法反算出地基中粘土层的平均固结系数和渗透系数。把用本文方法推算的渗透系数应用于太沙基方法计算路基沉降，发现比选用实验室测得的渗透系数计算的结果更接近实际沉降。通过本次反分析研究得出：路基中粘性土的固结系数和渗透系数明显高于室内土工试验测得值。这给相似地基高等级公路的设计、施工提供了参考依据。  相似文献