An Actively Controlled Wind Tunnel And Its Application To The Reproduction Of The Atmospheric Boundary Layer     

Cao Shuyang  Akira Nishi  Kimitaka Hirano  Shigehira Ozono  Hiromori Miyagi  Hiromori Kikugawa  Yuji Matsuda  Yasuo Wakasugi 《Boundary-Layer Meteorology》2001,101(1):61-76

An actively controlled wind tunnel equipped with multiple fansand airfoils has been developed, mainly for the purpose of reproducing the atmospheric boundary layer (ABL) for wind engineering applications. Various fluctuating flows can be achieved in this wind tunnel by altering the input data of the fans and airfoils through computer control. In this study, the ABL is physically simulated in this wind tunnel, and particular attention ispaid to the simulation of the profile of Reynolds stress. The method of generating the fluctuating flow and the experimental results of reproducing the ABL are presented. As the results show, the spatial distribution of Reynolds stress is satisfactorily simulated, and the profiles of other statisticalturbulent parameters, such as mean velocity, turbulent intensity, integral scale and power spectrum are successfully reproduced simultaneously.  相似文献   

地震测点误差对地震学参量的影响分析     

刘芳  曹井泉 《华北地震科学》2001,19(1):72-78

采用随机干扰方法，在地震观测误差容许值范围内，对地震观测资料进行人为随机干扰。在此基础上，使用干扰前后的资料对b值、η值、地震活动度S值、活动标度H值、等效地震M和频度N等6种地震学参量进行偏差分析，研究地震观测误差对地震学参量的影响。  相似文献   

甘肃酒泉Q_(y1)钻孔磁性地层划分与对比   总被引：6，自引：0，他引：6  

曹兴山 《地层学杂志》1997,21(4):259-266,F003

甘肃第四纪地质研究取得了丰硕成果，但因各家对第四纪地层划分的原则和依据不统一及其他原因，致使第四纪划分的一些基本问题尚无统一意见。为建立河西走廊地层层序，本文依据酒泉Ｑｙ１钻孔磁性地层特征、热释光测试成果、１４Ｃ资料及岩石地层特征进行地层划分。依据区域地质资料和古地磁成果，确定第四纪下限为２．４８Ｍａ，中更新世下限为０．７３Ｍａ，晚更新世下限为０．２０Ｍａ，全新世下限为０．０１２Ｍａ。  相似文献   

中国三叠纪中晚期—早更新世构造应力值的估算   总被引：13，自引：0，他引：13       下载免费PDF全文

万天丰  曹秀华 《地球科学》1997,22(2):145-152

选用具有测年数据的含石英或橄榄石的岩石，在透射电镜下观测位错密度，从而估算了中国三叠纪中、晚期—早更新世４３２个构造应力值（差应力值），初步发现在板块碰撞带或大断层带附近差应力值增大，而在板块内部则逐渐变小．在各构造期的晚期地壳上部平均差应力值也是不同的，印支期（２３０～２０８Ｍａ）为１０５．５ＭＰａ；燕山期（１７０～１３５Ｍａ）为９９．４ＭＰａ；四川期（１００～５２Ｍａ）为１０７．４ＭＰａ；华北期（３０～２３．３Ｍａ）为７６．７ＭＰａ；喜马拉雅期（１０～０．７３Ｍａ）为９２．６ＭＰａ．  相似文献   

太行山造山带岩浆活动特征及其造山过程反演   总被引：15，自引：0，他引：15       下载免费PDF全文

罗照华  邓晋福  赵国春  曹永清 《地球科学》1997,6(3)

太行山造山带被大多数学者称为构造岩浆带，被认为是中生代环太平洋岩浆弧的组成部分．立足于太行山地区燕山期侵入岩类的研究和对比，以岩浆起源、岩浆演化的最新理论作为基础和主线，采用从宏观→微观→宏观的分析对比手法，对不同时期、不同区段侵入岩类的岩石化学、地球化学特征及其反映的成因信息作了详细对比，从而提出了“太行山型”造山带的概念及其形成模式．认为太行山造山带属于一种新的造山带类型，受控于板缘俯冲作用的远距离效应．造山作用以强烈的岩浆活动为标志，以陆壳的双向增厚为特征  相似文献   

小江断裂带中段的北东向断裂与断块结构   总被引：8，自引：0，他引：8       下载免费PDF全文

沈军  俞维贤 《地震地质》1997,19(3):12-210

小江断裂带中段东西支断裂间存在的ＮＥ向断裂是在第三纪ＮＥ向断裂的基础上，于第四纪中晚期开始新的活动，并具有左旋走滑运动的特征，有些在全新世仍有活动。它们的活动从属于小江断裂带的整体左旋走滑运动，其运动幅度和速率比近ＳＮ向小江东西支断裂小得多，但是由于它们的运动，使主断裂产生弯曲或阶区，形成有利于应力和应变集中的障碍。夹于东西支断裂之间的断块被ＮＥ向断裂切割为多个次级菱形和梭形断块，这些断块之间的相对运动对断裂分段和地震孕育过程具有不可忽视的影响  相似文献   

赣皖边境地区青白口纪地层划分与对比   总被引：2，自引：0，他引：2  

廖洪鑫  聂剑华 《江西地质科技》1997,24(3):111-117

1:5万区调填图中系统调研了江西省内都昌县马涧桥、波阳县燕窝一带新发现的青白口纪地层岩石组合与层序、岩相特征,获得部分微古植物化石及847±38Ma的同位素测年数据,重新厘定并新建马涧桥组,据其特征认为可与毗邻的皖南青白口纪地层对比。四堡运动后,本区与皖南都曾经历过裂陷时期,具有相同的构造背景。  相似文献   

Late Cenozoic magnetostratigraphy (11 – 0 Ma) of the Dongshanding and Wangjiashan sections in the Longzhong Basin,western China     

Li  Ji-Jun  Fang  Xiao-Min  Van der Voo  Rob  Zhu  Jun-Jie  Mac Niocaill  Conall  Cao  Ji-Xiu  Zhong  Wei  Chen  Huai-Lu  Wang  Jianli  Wang  Jian-Ming  Zhang  Yie-Chun 《Geologie en Mijnbouw》1997,76(1-2):121-134

A paleomagnetic study of the 510-m-thick Wangjiashan section of Late Miocene and Pliocene terrestrial sediments reveals a fairly complete reversal record with ages from 11 to 1.8 Ma. The magnetostratigraphy of the Dongshanding section, located nearby, reveals a partially overlapping reversal record with ages from 2.2 to 0 Ma, and facilitates correlation of the Wangjiashan section with the global polarity time scale. A new stratigraphic division of the Wangjiashan section replaces the name Linxia formation by five new formation names, based on lithologic variation and mammalian fossil finds. The new formations and their magnetostratigraphically determined ages are: Dongshan Formation (c. 1.75–2.6 Ma), Jishi Fm. (c. 2.6–3.6 Ma), Hewangjia Fm. (4.5–6.0 Ma), Liushu Fm. (6.0–7.6 Ma), and Dongxiang Fm. (7.6–c. 12 Ma). The Neogene stratigraphy and fossil mammals suggest that the nearby part of the Tibetan Plateau experienced a persistent denudation during the Late Miocene and Early Pliocene, but that it was uplifted more rapidly at about 3.6 Ma.  相似文献   

试论地图形式美的规律     

曹永安 《测绘学院学报》1992,(3)

本文从六个方面阐述了地图形式美的规律性,最后进一步说明了其规律性与增强地图美感的关系。  相似文献   

PROSPECTING FOR THE HIDDEN ACTIVE FAULT BY MEASURING THE 218p0 AND 210p0          下载免费PDF全文

Zhang Yusong Hu Yutai Li Jianhua 《地震地质》1992,14(1):17

A method of prospecting for the concealed active fault by simultaneous measuring both 218Po and 210Po is introduced.It is a radioactive prospecting.The concentration of radon near the fault can be determined from the activities of its daughters 218Po and 210Po.At the fault,there is a good passage for gases,and the radioative gas from crustal depths can be easy to get to the surface.As a result,the level of the radioactivity there is quite high,but low at both sides far from there.The  相似文献