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复杂条件下工作面涌水量预测及排水系统优化研究 被引量:1
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作者 李建华 窦凤金 《煤矿机械》 2017年第1期93-96,共4页
锦界煤矿涌水水源主要来自风化基岩孔隙裂隙潜水和第四系上更新统萨拉乌苏组潜水含水层,结合近年大量观测数据,确定回采工作面(含准备面疏放水)及采空区涌水占矿井涌水量的95%以上,是矿井涌水量预测关键所在,利用钻孔流量实测数据的回... 锦界煤矿涌水水源主要来自风化基岩孔隙裂隙潜水和第四系上更新统萨拉乌苏组潜水含水层,结合近年大量观测数据,确定回采工作面(含准备面疏放水)及采空区涌水占矿井涌水量的95%以上,是矿井涌水量预测关键所在,利用钻孔流量实测数据的回归分析,得到了钻孔流量衰减特性及其计算公式,并分类计算工作面回采涌水量,并与现场实测结果进行了验证,实现了矿井涌水量快速、精准预测。在此基础上利用研究结果对工作面排水系统进行优化和改进,采用分区关联排水技术,极大地提高了排水系统运行效率。 展开更多
关键词 浅埋煤层 涌水量 衰竭系数 静态水量 补给水量
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Seismic stability of reinforced soil walls under bearing capacity failure by pseudo-dynamic method 被引量:6
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作者 阮晓波 孙树林 《Journal of Central South University》 SCIE EI CAS 2013年第9期2593-2598,共6页
In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by c... In order to evaluate the seismic stability of reinforced soil walls against bearing capacity failure,the seismic safety factor of reinforced soil walls was determined by using pseudo-dynamic method,and calculated by considering different parameters,such as horizontal and vertical seismic acceleration coefficients,ratio of reinforcement length to wall height,back fill friction angle,foundation soil friction angle,soil reinforcement interface friction angle and surcharge.The parametric study shows that the seismic safety factor increases by 24-fold when the foundation soil friction angle varies from 25°to 45°,and increases by 2-fold when the soil reinforcement interface friction angle varies from 0 to 30°.That is to say,the bigger values the foundation soil and/or soil reinforcement interface friction angles have,the safer the reinforced soil walls become in the seismic design.The results were also compared with those obtained from pseudo-static method.It is found that there is a higher value of the safety factor by the present work. 展开更多
关键词 reinforced soil walls seismic stability against bearing capacity seismic active force pseudo-dynamic method
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Gender differences in the etiology of heart failure: A systematic review
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作者 NahidAzad Anusha Kathiravelu Shabnam Minoosepeher Paul Hebert Dean Fergusson 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2011年第1期15-23,共9页
Background Heart failure (HF) is an increasing problem for the aging population, specifically among women. The etiology of HF influences both the selection and outcome of the treatment. There are variations between ... Background Heart failure (HF) is an increasing problem for the aging population, specifically among women. The etiology of HF influences both the selection and outcome of the treatment. There are variations between genders in morbidity and mortality in different studies, possibly reflecting etiology. The objective of this study was to examine the strength of evidence available for gender differences in the etiology of chronic heart failure. Methods Computer-assisted searches from 1980-2009 for gender differences in the etiology of heart failure were performed (Medline, EMBASE and PubMed). From 2347 abstracts reviewed based on inclusion criteria, 35 original articles were chosen for review. Data extraction was based on observational studies (prospective/retrospective cohort or cross sectional) with a mean follow up of 3 months. There was no interrater variability between the 2 reviewers on data-extraction. Results Ventricular systolic dysfunction being more associated with male sex, but female sex was more reported to be associated with preserved left ventricular function. Ischemic etiology and associated coronary heart disease were strongly correlated with male sex. The risk for HF was dramatically more elevated for women with systolic hypertension but the association for diabetes mellitus as the etiology of HF was somewhat equal between males and females. Conclusions One of the limitations in reaching conclusions about gender differences in cardiovascular disease is that many major clinical trials do not include a gender analysis nor they are powered to do so as women are under-represented in most of the HF studies. The need remains for a well designed prospective study of sufficient numbers of male and female patients with and without heart failure and analyzing etiology and risk factors based on the sex differences. 展开更多
关键词 heart failure gender differences ETIOLOGY
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