THE EFFECTS OF VERTICAL VARIATION OF BASIC FLOW AND HORIZONTAL GRADIENT OF TEMPERATURE ON LINEAR AND NONLINEAR GRAVITY WAVES          下载免费PDF全文

Xia Youlong  Zheng Zuguang 《Acta Meteorologica Sinica》1993,7(4):495-504

By using two-dimensional dynamical equations in x-z plane with Boussinesq approximation,the effects of the second-order vertical shear of the basic flow u_zz and the horizontal gradient of temperature (M) on the gravity wave and the isolated gravity wave are discussed.The magnitudes of u_zz and M corresponding to the linear and nonlinear stabilities of the gravity waves are worked out,respectively.The results show that amplitude and width of the isolate dgravity wave are closely related to u_zz and M.It is indicated that the isolated gravity wave with a width of about 10 km can be motivated by the disturbance of sub-synoptic scale in the certain ranges of flow field shear and temperature gradient,while the motivated waves may be associated with the cold surge ahead of a cold front and the other mesoscale synoptic systems.  相似文献   

Approximately-Balanced Drilling in Daqing Oilfield     

XiaBairu ZhengXiuhua LiGuoqing TianTuo 《中国地质大学学报(英文版)》2004,15(1):128-132

The Daqing oilfield is a multilayered heterogeneous oil field where the pressure are different in the same vertical profile causing many troubles to the adjustment well drillings. The approximatelybalanced drilling technique has been developed and proved to be efficient and successful in Daqing oilfield. This paper discusses the application of approximately-balanced drilling technique under the condition of multilayered pressure in Daqing oilfield, including the prediction of fornmtion pressure, the pressure discharge technique for the drilling well and the control of the density of drilling fluid.  相似文献   

基于灰色关联分析和案例推理的边坡稳定性评价方法   总被引：6，自引：0，他引：6  

李梅  夏元友 《岩土工程技术》2004,18(3):109-112,125

采用基于案例推理的方法 (CBR)来评价边坡稳定性 ,并利用灰色关联理论 ,提出基于灰色关联分析的案例检索方法 ,应用于边坡工程实例 ,效果良好 ,且将实例应用结果与同等条件下欧式距离的检索结果比较 ,说明此方法合理有效、具有明显的优越性  相似文献   

滑坡可视化地面模型   总被引：2，自引：0，他引：2  

田金华  池秀文  夏元友 《岩土工程技术》2004,18(3):144-146,153

简述了滑坡可视化地面模型的构建及可视化方法。介绍了可视化软件IDL的功能和特点。利用IDL中的TRIANGULATE函数和TRIGRID函数相结合 ,建立了基于Delaunay三角网的规则格网地面模型。最后 ,论述了滑坡可视化地面模型研究的意义。  相似文献   

常用相似性判据的检验和综合相似系数的使用   总被引：12，自引：2，他引：12       下载免费PDF全文

阎惠芳李社宗  黄跃青张霞 《气象科技》2003,31(4):211-215

文章对相似预报方法常用的几个相似性判据作了客观检验和讨论，同时提出了综合相似系数，2000年6～8月黄淮主汛期郑州市气象台降水预报业务现场试验表明，综合相似系数在降水相似预报和24h暴雨预报中有较好的表现。  相似文献   

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