Using large-scale diagnostic quantities to investigate change in East Coast Lows     

Fei Ji  Jason P. Evans  Daniel Argueso  Lluis Fita  Alejandro Di Luca 《Climate Dynamics》2015,45(9-10):2443-2453

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Sandstone Turning by Abrasive Waterjet     

Petr Hlaváček  Ján Cárach  Sergej Hloch  Karol Vasilko  Dagmar Klichová  Jiří Klich  Dominika Lehocká 《Rock Mechanics and Rock Engineering》2015,48(6):2489-2493

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高密度电阻率法在果香峪溶洞勘查中的应用效果分析     

尹极  王晓东  程邈  李振宇 《CT理论与应用研究》2011,20(3):301-310

地下岩溶的发育影响着地面基础工程的安全使用,所以,我们要对岩溶地区发育特征进行全面的了解,以采取相应的措施保证该地区地面建筑的安全。溶洞的空间赋存状态一般是不规则的三维地质体,它的发育与地下水系及该地区的地质构造有紧密联系,造成溶洞的洞室可能含有高阻或低阻填充物,导致溶洞与围岩之间存在物性差异。高密度电阻率法正是利用物...  相似文献   

Pseudo-dynamic test and numerical simulation of high-strength concrete frame structure reinforced with high-strength rebars     

Xin Chen  Shi Yan  Baojian Ji 《地震工程与工程振动(英文版)》2011,10(2):303-311

This paper describes an investigation of a high-strength concrete frame reinforced with high-strength rebars that was tested in the structure engineering laboratory at Shenyang Jianzhu University. The frame specimen was pseudo- dynamically loaded to indicate three earthquake ground motions of different hazard levels, after which the test specimen was subjected to a pseudo-static loading. This paper focuses on the design, construction and experiment of the test frame and validation of the simulation models. Research shows that a high-strength concrete frame reinforced with high-strength rebars is more eff icient and economical than a traditional reinforced concrete frame structure. In addition to the economies achieved by effective use of materials, research shows that the frame can provide enough strength to exceed conventional reinforced concrete frames and provide acceptable ductility. The test study provides evidence to validate the performance of a high- strength concrete frame designed according to current seismic code provisions. Based on previous test research, a nonlinear FEM analysis is completed by using OpenSees software. The dynamic responses of the frame structure are numerically analyzed. The results of the numerical simulation show that the model can calculate the seismic responses of the frame by OpenSees. At the same time, the test provides additional opportunities to validate the performance of the simulation models.  相似文献   

Regional climate change and local urbanization effects on weather variables in Southeast China   总被引：2，自引：0，他引：2  

Ji Chen  Qinglan Li  Jun Niu  Liqun Sun 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(4):555-565

This paper presents the analyses of regional climate change features and the local urbanization effects on different weather variables over Southeast China. The weather variables considered are: daily mean (T_m), minimum (T_min), and maximum (T_max) near surface air temperature, diurnal temperature range (DTR), relative humidity (RH), and precipitation (P). With analysis of two datasets (a station dataset for the period from 1960 to 2005 that is mainly used and a grid dataset for the period 1960–2000), this study reveals that the trends in the variations of these weather variables can be separated into two periods, before and after 1984. Before 1984, there were no significant urbanization effects, and T_min, RH, and P steadily increased but T_max decreased, resulting in a considerable decrease in DTR and a slight decrease in T_m. After 1984, T_min and T_max increased considerably, and the urbanization influence on T_min, but not T_max, is observable. The urbanization effect causes an extra increasing trend in T_min with a rate of about 0.6°C/decade and, accordingly, extra decreasing trends in DTR and RH. The analysis of the seasonal trends reveals that the urbanization influence results in a near-uniform increase of T_min for all four seasons and a strong decrease of RH in summer and autumn. Moreover, there is no significant change in P at the annual scale and an increasing rate of 11.8%/decade in summer. With the urbanization influence, a considerable increase in P is noticeable at the annual scale; specifically, the increasing rates of 18.6%/decade in summer and 13.5%/decade in autumn are observed.  相似文献   

西藏甲玛中酸性侵入岩LA-ICP-MS锆石U-Pb定年及成矿意义   总被引：13，自引：7，他引：6  

秦志鹏  汪雄  多吉  唐晓倩  周云  彭惠娟 《矿床地质》2011,30(2):339-348

文章研究了甲玛矿区内中酸性侵入岩的侵位时序及岩浆-成矿作用.以实测地质资料为基础,结合中酸性侵入岩的LA-ICP-MS锆石U-Pb定年,初步厘定了甲玛矿区内中酸性岩浆岩的侵位时序,从早至晚依次为:花岗斑岩(15.31～16.27 Ma)-石英闪长玢岩-二长花岗斑岩(14.81 Ma)-花岗闪长斑岩.以辉钼矿为例,甲玛矿...  相似文献   

High-Temperature Mechanical Properties of Mudstone in the Process of Underground Coal Gasification   总被引：4，自引：2，他引：2  

Ji’an Luo  Lianguo Wang 《Rock Mechanics and Rock Engineering》2011,44(6):749-754

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大别山早白垩世变质核杂岩的结构与演化   总被引：7，自引：0，他引：7       下载免费PDF全文

冀文斌  林伟  石永红  王清晨  褚杨 《地质科学》2011,46(1):161-180

大别山中部混合岩-片麻岩穹隆的构造属性认识方面一直众说纷纭.通过对中大别杂岩及其边界剪切带或断裂带的构造解析,并结合对前人相关研究的总结,我们将中大别杂岩厘定为早白垩世的变质核杂岩,其中商麻断裂与晓天-磨子潭断裂和水吼-五河剪切带构成了一个完整的拆离断层带,并将变质核杂岩的形成时间限定在145～120 Ma.中大别杂岩...  相似文献   

柴木铁路沼泽化冻土区热管冷却半径的观测研究     

陈继  徐舜华  窦顺  张鲁新 《冰川冻土》2011,33(4):897-901

柴达尔-木里铁路沿线高温沼泽化多年冻土广泛发育,约20km的冻土路基采用了热管降温措施．借鉴青藏铁路的成功经验,热管的纵向和横向间距均设计为3m,并针对铁路东南-西北的不利走向,在阳坡布设了双排热管．为验证热管措施在多年冻土湿地路段设计参数的合理性,2008年底在柴达尔-木里铁路中段布设了热管冷却半径观测试验场,该观测...  相似文献   

Latest Devonian to earliest Carboniferous conodont and carbon isotope stratigraphy of a shallow‐water sequence in South China     

Wenkun Qie  Xiang‐Dong Wang  Xionghua Zhang  Wenting Ji  Ethan L. Grossman  Xing Huang  Jiangsi Liu  Genming Luo 《Geological Journal》2016,51(6):915-935

To improve regional and intercontinental correlation of the uppermost Devonian–lowermost Carboniferous, we examined the conodont faunas and carbon isotopic records of the Tangbagou Formation in the Qilinzhai section, southern Guizhou, South China. The Tangbagou Formation is a succession of mixed carbonate–siliciclastic rocks that accumulated on a shallow‐water platform under normal marine conditions. Seven conodont zones for shallow‐water biofacies in South China, the Cl. gilwernensis–Cl. unicornis Zone, the Po. spicatus Zone, the Si. homosimplex Zone, the Si. sinensis Zone, the Si. eurylobata Zone, the Ps. multistriatus Zone and the Po. co. porcatus Zone in ascending order, are recognized in the Tangbagou Formation. Although apparently limited in its value for global correlation, this conodont zonation is more applicable to shallow‐water biofacies in South China. Carbonate samples have yielded carbon isotopic signatures consistent with those recorded in Euroamerica sections, in particular showing four distinct characteristics: (1) the peak values of Hangenberg Carbon Isotope Excursion (HICE) during the latest Devonian, (2) a minor positive shift (P1) in the Si. homosimplex Zone during the early Tournaisian, (3) a second minor positive shift (P2) in the Si. sinensis Zone and (4) the middle Tournaisian Carbon Isotope Excursion (TICE) in the middle part of the Tangbagou Formation. The similarity in peak values (~5.5‰) and magnitude of TICE for the Qilinzhai and Belgian sections indicates that the Euro‐asia δ¹³C_carb trends may reflect the changes in global mean ocean δ¹³C_DIC, rather than having been overprinted by local carbon cycling. Integration of conodont biostratigraphy and δ¹³C stratigraphy provides a powerful tool for stratigraphic correlation. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献