Constituent material properties and clast-size distribution of volcanic breccia     

Atsushi Saotome  Ryunoshin YoshinakaMasahiko Osada  Hiroyasu Sugiyama 《Engineering Geology》2002,64(1):1-17

Volcanic breccia is a representative heterogeneous rock. As a preliminary study for determining its mechanical properties in laboratory and field experiments, its material properties and structural features were described. Three-dimensional clast-size distribution was also estimated for the study site using the theory of stereology. With this distribution determined, a numerical simulation was performed to investigate the relationship between the volumetric proportion of clasts in a sample and the areal proportion and maximum length of clasts on a lateral surface of the sample. The following observations were made: (1) coefficients of variation for volumetric proportion are dependent on the size of the sample, and became large when the size of the sample is small; (2) samples with a small coefficient of variation can be selected at any size if a restriction is placed on the ratio, D_max/D₀, of the maximum length of clasts to the size of the sample; and (3) the volumetric proportion of clasts in each sample can be estimated from the observed areal proportions within an error range that depends on the whole volumetric proportion.  相似文献   

VB在工程测量中的应用     

潘军 《测绘与空间地理信息》2002,25(2):34-35

论述了VB在测量计算中的特点 ,并结合实例阐述了利用VB进行前方交会计算的实现方法 ,从而为利用交会计算及坐标换算等较为复杂的公式计算提供了一条可行的途径  相似文献   

氮离子注入对钻杆接头材料表面硬度的影响          下载免费PDF全文

刘丽吴东江  庄娟马腾才  田云霞王连元 《探矿工程》2004,31(3):34-35

对钻杆接头材料30CrMnSiA钢的样品进行氮离子注入表面改性试验，结果表明，在不同载荷的情况下，选用氮的注入量为50×1017 N+/cm2是比较合适的，氮离子注入后样品的表面努氏硬度提高1倍多。  相似文献   

渤海湾地区不同方向断裂带的封闭性   总被引：24，自引：8，他引：24  

万天丰  王明明  殷秀兰  晋香兰 《现代地质》2004,18(2):157-163

构造应力场的最大主压应力方向与同时期活动断裂走向的相互关系决定着断裂的封闭程度 ,两者的锐夹角越大 ,断裂的封闭性越好 ;两者的锐夹角越小 ,断裂的封闭性越差 ,渗透性越好 ,有利于流体的运移。据此用线性代数法换算出的断裂闭合系数可半定量地评价断裂的封闭条件 ;再结合不同油气主运移期的封闭性变化的历史 ,可对断裂带的有利的油气聚集部位进行预测。通过对渤海湾地区的油气聚集进行综合评价 ,认识到东西向和南北向展布的断陷带对油气的聚集最为有利 ,北西向展布的和现今断裂活动性较弱的北东向展布的断陷带中的部分地段也很有前景。预测庙西 1号、垦利 3号、庙西 3号等断裂带为下一步有利的油气勘探构造带。  相似文献   

Beyond environmental impact: articulating the “intangibles” in a resource conflict     

Krisnawati Suryanata  Karen Umemoto   《Geoforum》2005,36(6):750-760

Environmental planning is an arena of policy making in which formal public deliberation is among the most extensive. At the same time, environmental disputes can also be among the most resistant to resolution, often becoming entangled in issues that some describe as “intangible”. The discourse is largely structured by regulatory frameworks, such as environmental impact assessment laws and procedures, which focus primarily on operational rights (what one can or cannot do where and when) and tangible impacts on the physical or natural environment. A comparative case study of mariculture in Hawai‘i reveals that a large measure of public concerns focused on collective choice rights (who has a right to make which decisions on behalf of whom) and the more intangible impacts to the social or cultural environment. These concerns are often nested in a historic context that has implications for the social processes that they create. The findings from this study imply a need for more structured or systematic ways to deliberate issues of collective choice rights alongside operational rights within the larger process of environmental planning.  相似文献   

考虑流-固耦合影响的挡水结构自振特性   总被引：1，自引：0，他引：1  

郭永刚  赵晓飞  石革清 《世界地震工程》2004,20(3):78-83

对流体-固体之间的动力相互作用的问题，采用流体有限元法研究结构自振特性的影响。建立了流固耦合运动方程体系，并对耦合方程组的求解过程进行了推导与阐述。编制了流体有限元自动生成程序，使得流固耦合问题从建立模型到分析能够利用计算机自动实现。最后以挡水结构作为算例，分别就不同水位工况和水体采用不同长度模型对结构振动的影响进行了分析。  相似文献   

不同类型地震的地震矩-震级标度关系研究   总被引：2，自引：2，他引：2       下载免费PDF全文

钟羽云  朱新运  张震峰 《地震工程学报》2004,26(1):57-61

收集整理了中国大陆1977～2001年发生的107次M≥5．0地震的震型、震源机制、发震断层、地震矩等参数，在此基础上研究了不同震型、不同断层性质地震的地震矩与震级的关系。结果表明，地震矩和震级标度关系中直线的斜率与地震视应力和介质非均匀程度相联系，走滑断层地震的视应力和介质的非均匀程度均高于非走滑断层地震，走滑断层中孤立型地震的视应力和介质的非均匀程度均低干多震型地震。  相似文献   

GEOGRAPHIES OF RISK AND DIFFERENCE IN CROP GENETIC ENGINEERING     

KATHLEEN MCAFEE 《Geographical review》2004,94(1):80-106

ABSTRACT. Genetic engineering is often depicted as a breakthrough solution to hunger and environmental problems in agriculture. Such claims encourage the further shift of public resources toward molecular sciences, globalized intellectual property rights, and relaxed biotechnology regulation. However, focusing on transgenic crops is a risky and inadequate response to socioeconomic and ecological challenges. The search for a universal, technological solution disregards the complex geographies of food production and trade. This article challenges claims that crop genetic engineering represents a new direction in agriculture, that transgenic crops have performed well, and that the regulatory approaches used in the United States or Europe are universally applicable. It outlines three geographies of difference that distinguish agriculture in the global North from farming in most of the global South. Those differences point to the need for more place‐specific, multifaceted, and farmer‐centered approaches to agricultural productivity and sustainability, approaches to which geographers have much to contribute.  相似文献   

大庆长垣以东地区登二段泥质岩盖层封气能力综合评价   总被引：3，自引：3，他引：3  

薛永超  程林松  付广 《吉林大学学报(地球科学版)》2005,35(5):626-631

为了使泥质岩盖层评价更具客观性和通用性,在对大庆长垣以东地区登二段泥质岩盖层宏观发育特征和微观封闭能力深入研究的基础上,基于达西定律,提出利用天然气通过泥质岩盖层渗滤速度指数进行盖层封闭性综合评价的方法,并给出各参数的确定方法和评价流程.应用该方法对研究区泥质岩盖层封气能力进行了综合评价,结果表明:在肇深1井-芳深4井-芳深5井-芳深1井-汪9-12井-汪903井一线井区附近及其以西地区,具有好的封气能力.在肇深3井-朝2井-三深1井一线及其南侧和青2井-五深1井-四深1井-川3井等井区,具有中等封气能力.在二深1井-朝深2井-肇深2井南侧,具有差封气能力.在盖层分布的其它地区,具有较好的封气能力.  相似文献   

用芳香化合物分布判别储层产液性质   总被引：1，自引：1，他引：1  

岳兴举  王振平  菅云英  孔令芳  颜红霞 《地球化学》2005,34(2):180-186

储层产液性质判别是录井、测井的基本任务,也是难题之一.特别在涉及到含水油层和含油水层的判别时,更是缺少可靠而有效的方法.利用芳香化合物在油水两相中的分配原理和反相液相色谱对芳香化合物的分离检测技术,测试了67块已知产液性质的储层样品,在此基础上,建立起了两张判别储层产液性质的地球化学图,其对油层、含水油层、含油水层及水层的综合对判率都在83%以上.  相似文献