碎岩刀具工作面圆弧化机理及解决途径   总被引：2，自引：0，他引：2       下载免费PDF全文

汪国香  杨凯华 《探矿工程》1998,(1):46-48

通过分析孕镶金刚石刀头碎岩和磨损机理,找出引金刚石刀头工作端面弧化的原因,并提出了克服圆弧化现象的几种方法。  相似文献   

Effect of sea spray on the numerical simulation of super typhoon ‘Ewiniar’   总被引：1，自引：0，他引：1  

Jing Zheng  Jianfang Fei  Tao Du  Yuan Wang  Xiaoyan Cui  Xiaogang Huang  Qiming Li 《中国海洋大学学报(英文版)》2008,7(4):362-372

To study the potential effect of sea spray on the evolution of typhoons,two kinds of sea spray flux parameterizationschemes developed by Andreas (2005) and Andreas and Wang (2006) and Fairall et al.(1994) respectively are incorporated into theregional atmospheric Mesoscale Model version 3.6 (MM5V3) of Pennsylvania State University/National Center for AtmosphericResearch (PSU/NCAR) and the coupled atmosphere-sea spray modeling system is applied to simulate a Western Pacific super ty-phoon Ewiniar in 2006.The simulation results demonstrate that sea spray can lead to a significant increase in heat fluxes at theair-sea interface and the simulated typhoon's intensity.Compared with the results without sea spray,the minimum sea level pressurereduces about 8hPa after taking account of sea spray by Fairall et al.'s parameterization (1994) and about 5hPa by Andreas' (2005)and Andreas and Wang's (2006) parameterization at the end of the model integration,while the maximum 10m wind speed increasesabout 17% and 15% on average,respectively,through the entire simulation time period.Taking sea spray into account also causessignificant changes in Tropical Cyclone (TC) structure due to an enhancement of water vapor and heat transferred from the sea sur-face to the air; therefore,the center structure of the typhoon becomes more clearly defined and the wind speed around the typhooneye is stronger in numerical experiments.The simulations show that different sea spray flux parameterizations make different modifications to the TC structure.  相似文献   

钱塘江河口护塘丁坝的研究进展     

严盛  孙志林  赵渭军  林炳尧 《海洋学研究》2008,26(2):75-81

从作为河道整治或护岸的辅助建筑物的丁坝的原型观测、模型试验到工程实践等多种手段对钱塘江强潮河口段各个历史阶段护塘丁坝的研究成果进行了回顾和总结。钱塘江护塘丁坝技术在抗击强涌潮的过程中被不断推进、发展和创新,为钱塘江海塘的防护发挥了至关重要的作用。  相似文献   

Transient solution for radial two‐zone flow in unconfined aquifers under constant‐head tests     

Y. C. Chang  H. D. Yeh  G. Y. Chen 《水文研究》2010,24(11):1496-1503

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A conceptual–numerical model to simulate hydraulic head in aquifers that are hydraulically connected to surface water bodies     

David Pulido‐Velazquez  Andrés Sahuquillo  Joaquín Andreu 《水文研究》2012,26(10):1435-1448

In this paper, we present a conceptual‐numerical model that can be deduced from a calibrated finite difference groundwater‐flow model, which provides a parsimonious approach to simulate and analyze hydraulic heads and surface water body–aquifer interaction for linear aquifers (linear response of head to stresses). The solution of linear groundwater‐flow problems using eigenvalue techniques can be formulated with a simple explicit state equation whose structure shows that the surface water body–aquifer interaction phenomenon can be approached as the drainage of a number of independent linear reservoirs. The hydraulic head field could be also approached by the summation of the head fields, estimated for those reservoirs, defined over the same domain set by the aquifer limits, where the hydraulic head field in each reservoir is proportional to a specific surface (an eigenfunction of an eigenproblem, or an eigenvector in discrete cases). All the parameters and initial conditions of each linear reservoir can be mathematically defined in a univocal way from the calibrated finite difference model, preserving its characteristics (geometry, boundary conditions, hydrodynamic parameters (heterogeneity), and spatial distribution of the stresses). We also demonstrated that, in practical cases, an accurate solution can be obtained with a reduced number of linear reservoirs. The reduced computational cost of these solutions can help to integrate the groundwater component within conjunctive use management models. Conceptual approximation also facilitates understanding of the physical phenomenon and analysis of the factors that influence it. A simple synthetic aquifer has been employed to show how the conceptual model can be built for different spatial discretizations, the parameters required, and their influence on the simulation of hydraulic head fields and stream–aquifer flow exchange variables. A real‐world case was also solved to test the accuracy of the proposed approaches, by comparing its solution with that obtained using finite‐difference MODFLOW code. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

吸附态轻烃气相色谱分析方法及其在天然气水合物测定中的应用   总被引：1，自引：0，他引：1  

陈卫明  徐仁廷  李庆霞  肖细炼  薄玮  张勤 《物探与化探》2012,(5):775-782

建立了毛细管柱气相色谱测定土壤中吸附态轻烃（酸解烃、顶空气轻烃）的方法,采用适于批量处理的酸解烃样品制备和通过振荡、加热达到解吸平衡的顶空气样品制备的前处理方法,在优化的仪器条件下,对天然气水合物区土壤中吸附态轻烃进行检测。顶空气轻烃的方法检出限为0．018×10^-6（以甲烷计算）,精密度为6．6％（甲烷）-16％（异丁烷）;酸解烃的方法检出限为0．016μL／kg（以甲烷计算）,精密度为2．2％（甲烷）～19％（正戊烷）。该方法应用于大批量实际样品分析中,效果良好。  相似文献   

渐缩渐扩洞塞消能和空化特性   总被引：1，自引：0，他引：1  

尹则高  郑清鑫  王乐  曹先伟 《水科学进展》2012,23(5):687-694

建立了三维RNG k-ε紊流数学模型和突缩突扩洞塞泄流的物理模型试验,利用实验结果对数学模型进行了验证,利用验证后的数学模型对突缩突扩洞塞和渐缩渐扩洞塞的水头损失系数和空化数进行了计算。结果表明,洞塞渐缩(或渐扩)段相对长度一定时,随着渐扩(或渐缩)段相对长度的增加,水头损失系数减小,最小空化数增加。当渐缩段和渐扩段几何尺寸互换时,水头损失系数和最小空化数的变化不大;其他几何参数一定的情况下,随着横断面半径收缩比的减小,水头损失系数增加,最小空化数降低。圆弧连接情况下,随着圆弧夹角的增加,水头损失系数呈现先降低后增加的趋势;而最小空化数呈现先增加后降低的趋势。其他几何参数一定的情况下,圆弧连接的水头损失系数小于斜线连接的对应值,最小空化数则相反。在水头损失系数和最小空化数权重相等的假定条件下,初步探讨了渐缩渐扩洞塞几何体型参数的优化方法,给出了渐缩渐扩洞塞的最优几何体型参数。  相似文献   

陕西禾草沟煤矿工业场地主厂房段古滑坡变形破坏特征及稳定性分析     

吕远强  刘庆雪  李寅良  林杜军 《中国地质灾害与防治学报》2012,23(3):1-7

工程建设引发禾草沟煤矿工业场地主厂房段古滑坡复活,通过野外调查和测量、钻探、探槽、变形监测、室内试验和数值计算,分析该古滑坡的复活原因及变形破坏特征;采用改进的数值计算法对古滑坡的稳定性进行分析,古滑坡在天然条件下处于稳定状态;对古滑坡复活采用"削头压脚"措施后,稳定性满足安全要求,这对古滑坡的治理设计提供了理论依据。同时,该措施能节约工程投资,缩短工期,具有良好的经济效益。  相似文献   

我国地质找矿钻探技术装备现状及发展趋势分析          下载免费PDF全文

张林霞  李艺  周红军 《探矿工程》2012,39(2):1-8

在对我国地质找矿钻探技术装备发展经济环境分析的基础上,通过调研和统计数据,分析了我国地质找矿钻探技术和装备的现状及发展趋势,包括岩心钻机的生产、销售和使用情况,煤层气钻机的现状,施工单位对新技术、新装备的需求等。提出了我国地质找矿钻探技术及装备发展的建议。  相似文献   

YSZ-50型声频振动钻机动力头减振方案的改进          下载免费PDF全文

赵晓冬  吴浩  陆卫星  任晓飞  刘宝林 《探矿工程》2012,39(12):1-3

针对YSZ-50型声频振动钻机动力头存在的减振问题,通过分析国内外声频动力头减振方案的特点,提出了一种三道复合减振方案：第一道采用竖向销轴中的金属橡胶减振垫减振方式,吸收掉振动器振动能量的绝大部分,该方式为主要减振手段;第二道采用侧向复合橡胶块减振方式,吸收掉振动器传递到箱体振动能量的绝大部分,第三道采用普通橡胶垫减振方式,吸收掉箱体传递到回转马达的振动能量。试验表明,三道复合减振方案可有效解决YSZ-50型钻机动力头的减振问题。  相似文献