Burst strain disturbance — A new test study on fracture precursor     

Zhao-Yong Xu  Run-Hai Yang  Bin Wang  Jin-Ming Zhao  Yu-Feng Yao  Pei-Zhong Hua  Shi-Rong Mei 《地震学报(英文版)》1998,11(6):737-744

A multi-functional high-frequency seismometer, a new instrumental system, is used for recording multi-point strain variations of rock samples in the process of fracture development. The results indicate that strain in each point appears burst disturbance synchronously besides a tendency variation before main fracture. The burst disturbance could probably be one of the short-impending precursors before great earthquake.  相似文献   

硅酸盐细菌GY92对伊利石的释钾作用   总被引：26，自引：2，他引：24  

连宾 《矿物学报》1998,18(2):234-238

1992年在贵阳郊区玉米地中分离出一株硅酸盐细菌GY92,为探求GY92对伊利石的释钾作用,对采用的有关材料和方法、相关实验所获的GY92个体形态及培养特征、部分生理生化特征及其对伊利石的释钾作用等结果作了较详细的介绍,同时就GY92对伊利石的释钾机理等问题进行了简单讨论。  相似文献   

含硬包体试样在破裂孕育过程中波速场的变化   总被引：2，自引：2，他引：0  

王彬  胡毅力 《地震研究》1998,21(3):256-260

含硬包体混凝土试样在底面支撑侧面双轴加压至主破裂的情况下波速场的变化图象为：加压初期,试样上的纵波平均速度在４１７５～４６１５ｍ／ｓ之间变化,随着压力升高,出现小于４１７５ｍ／ｓ的低速区,但范围甚小,位置在两个包体之间。随后出现大于４６１５ｍ／ｓ的高速区,范围大致与包体位置一致。随着σ１的增加,低速区在逐渐变大,高速区逐步减小后又重新变大,高速区与低速区在平面上相互重叠,在空间上看,高速区被低速区包围着。临近主破裂时,低速区变小并逐步形成条带,高速区也变小,主要集中在靠近未来出现破裂的一个包体位置上。最终的破裂面出现在此高速区与低速条带交界附近,包体也局部破裂了。  相似文献   

地震综合前兆场建场方法初探          下载免费PDF全文

夏玉胜  梁子斌  蔡红卫  张慧  杨丽萍  张敏 《地震工程学报》1998,20(1):42-46

初步建立了一种能反映地震前兆时空演化全貌的无量纲、归一化可迭加的信息场———综合前兆场．通过对研究区（东经１１３°～１２５°,北纬３２°～４４°）前兆场时空演化过程的分析发现,地震前前兆场由正常的低值离散逐渐发展为围绕震中呈高值封闭状态,震后恢复正常．该方法的独特之处在于,避开了某些单项异常对应某具体源的分析,而是只考虑异常．根据前兆场的变化可以确定震源的大致位置  相似文献   

我国首座卫星信道数字化地震台网落成   总被引：1，自引：0，他引：1  

赵永  王斌 《国际地震动态》1998,(9):18-21

文章较为详细地介绍了我国第一座卫星信道数字化地震观测台网各配套仪器的性能,使用环境及整套系统的运行情况和目前在地震观测中所起的作用。作者展望了该系统的发展前景及其对我国地震观测事业的影响。  相似文献   

Geochronology and Geochemistry of Ore-related Granitoids in the Giant Gariatong Rb Deposit, Tibet and Implications for Rb Metallogeny in China     

LIN Bin  TANG Juxing  TANG Pan  SUN Yan  QI Jing  M. SANTOSH  XIE Jinling  DENG Shilin  LI Faqiao  XIE Fuwei  ZHOU Aorigele 《《地质学报》英文版》2024,98(1):83-103

Rubidium (Rb) deposits mostly occur in the South China and Central Asia orogenic belts and are often closely associated with highly differentiated granites. This study investigates a newly-discovered giant Rb deposit at Gariatong in the Central Lhasa terrane in Tibet. Detailed field studies and logging data revealed that the Rb mineralization mainly occurs in monzogranite and is related to greisenization. LA-ICP-MS U-Pb dating of zircon yielded ages of 19.1 ± 0.2 Ma and 19.0 ± 0.2 Ma for greisenized monzogranite and fresh monzogranite, respectively. The monzogranites are characterized as strongly peraluminous, with high contents of SiO2, Al2O3, K2O and Na2O as well as a high differentiation index. They are enriched in light rare earth and large ion lithophile elements with signi?cant negative Eu anomalies and depleted high field-strength elements. Petrological and geochemical features of these ore-related monzogranites suggest that they are highly fractionated S-type granites, derived from remelting of crustal materials in a post-collisional setting. The geochemistry of zircon and apatite points to a low oxygen fugacity of the ore-related monzogranite during the magma’s evolution. The discovery of the Gariatong Rb deposit suggests that the Central Lhasa terrane may be an important region for rare metal mineralization.  相似文献   

Three-dimensional scour below offshore pipelines in steady currents     

Liang Cheng  Kervin Yeow  Zhipeng Zhang  Bin Teng 《Coastal Engineering》2009,56(5-6):577-590

This paper presents the results of an experimental investigation on three-dimensional scour below offshore pipelines subject to steady currents. The major emphasis of the investigation is on the scour propagation velocity along the pipeline after the scour initiation. Physical experiments were conducted to quantify the effects of various parameters on scour propagation velocity along the pipeline in a water flume of 4 m wide, 2.5 m deep and 50 m long. Local scour depths directly below the model pipeline were measured using specifically developed conductivity scour probes. Effects of various parameters such as pipeline embedment depth, incoming flow Shields parameter and flow incident angle (relative to the pipeline) on scour propagation velocity along the pipeline were investigated. It was found that scour propagation velocity generally increases with the increase of Shields parameter but decreases with the increase of the pipeline embedment depth. A general predictive formula for scour propagation velocity is proposed and validated against the experimental results.  相似文献   

A complex variable solution for stress and displacement field around a lined circular tunnel at great depth     

Ming‐Bin Wang  Shu‐Cai Li 《国际地质力学数值与分析法杂志》2009,33(7):939-951

By applying the series expansion technique in the complex variable method established by Muskhelishvili, the plane elasticity problem for the stress and displacement field around a lined circular tunnel in conjunction with the consideration of misfit and interaction between the liner and the surrounding geomaterial is dealt with. The tunnel is assumed to be driven in a homogeneous and isotropic geomaterial. The coefficients in the Laurent series expansion of the stress functions are determined. The complex potentials in the liner and the surrounding geomaterial are explicitly derived, respectively. As an example, the case of a lined circular tunnel located in an isotropic initial stress field but subjected to uniform internal pressure is numerically considered. Numerical results indicate that the installation of tunnel liner can reduce the influences of the tunnel excavation on the in situ displacement and stress fields. However, the relative thickness and rigidity of the liner should be in an appropriate range. In addition, the effect of the tunnel excavation upon the displacement field is more significant than that upon the stress field. As far as the stress field in the surrounding geomaterial is concerned, when the ratio between the cover depth of tunnel and the tunnel radius is larger than 5, the results for the stress field in the paper are applicable. When the ratio between the tunnel depth and the tunnel radius is larger than 20, the results are applicable for the displacement field. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

高效分解水产原料的菌株分离鉴定和组合发酵初探     

宋敏  刘为  张鹰炯  童晓倩  李鹏  王斌  罗红宇 《海洋与湖沼》2015,46(4):800-807

为从一种组成未知的商用复合菌中分离并筛选出优势发酵菌株,本实验采用稀释平板培养法,对菌种进行分离纯化,同时参照《真菌鉴定手册》和《常见细菌鉴定手册》,根据其形态学特征、生理生化特性,并分别结合16S r DNA和18S r DNA序列的比对分析对菌种进行鉴定。另外,本研究通过生长曲线测定,单菌种发酵试验以及多菌种混合发酵发酵试验,以游离氨基酸态氮为指标,以期筛选出发酵低值水产品制备菌肥的最佳菌株组合。结果显示,共分离得到4株菌,分别为a热带假丝酵母、b罗伦隐球菌、c枯草芽孢杆菌、d蜡样芽胞杆菌。且菌种组合acd发酵后游离氨基酸态氮的含量较对照组上升最显著,为8.276g/L。故可确定最佳发酵菌株配方为acd(热带假丝酵母+枯草芽孢杆菌+蜡样芽胞杆菌)。  相似文献   

南渡江河口洪、枯季节水文泥沙变化特征及台风“海鸥”对入海水沙的影响   总被引：1，自引：0，他引：1  

陈斌  高飞  印萍  刘金庆 《海洋与湖沼》2015,46(6):1279-1291

基于2014年最新的洪、枯季节实测资料,分析了南渡江河口海域水文泥沙的季节性变化特征,借助台风"海鸥"过境期间的河道监测数据,研究了台风天气造成的洪水事件对河流入海水沙通量的影响。研究结果表明:(1)洪、枯季节河口海域的水体层化作用不强,洪季的水温高于枯季,但盐度低于枯季。水温呈现向海递减的趋势,而盐度整体分布较为均匀;(2)河口水体含沙量近岸大于远岸,枯季河口三角洲泥沙向西输运。洪季含沙量明显高于枯季,大量泥沙在台风季节被冲刷入海,而后向海或向西输运扩散;(3)河口海域为不规则全日潮,呈现东西向往复流特征。温度、盐度和浊度均呈现较强的潮汐性变化特征;(4)枯季河道内存在明显的盐水楔,锋面处的垂向梯度很大,在口门向陆大约12—15 km以远的河道水体不再受潮汐影响;(5)台风"海鸥"影响下,南渡江洪峰期间的径流量和含沙量均远远超过多年平均值,反映了南渡江河口地区"台风季节"的特点。  相似文献