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11.
为了研究硬煤破坏过程中的动态力学特性,采用Φ50 mm变截面分离式霍普金森压杆(SHPB)试验系统,对45#钢制薄壁套筒施加环向约束的硬煤试件进行不同加载速率的冲击压缩试验,得到被动围压下轴向应力-应变曲线、径向应力-应变曲线及最大被动围压和冲击速度的关系。研究结果表明:峰值应力、峰值应变随着冲击速度的增大而增大,最大被动围压值与冲击速度呈幂次增长的关系;被动围压下的硬煤试件变形受到限制,试件延性、抗压能力显著提高;随着冲击速度的增大,薄壁套筒对试件的约束也逐渐增大,达到峰值后,冲击速度对被动围压的影响减小,筒壁厚度影响着被动围压效果。  相似文献   
12.
岩体严重风化、垮塌和裂隙发育是库木吐拉千佛洞普遍存在的地质环境病害.风化岩体锚固机理的研究和灌浆材料的优选是对洞窟实施有效安全保护的关键。现场试验结果表明:锚固体的破坏产生于岩体与灌浆体的接触面.抗拔力与锚固长度无明显线性关系.存在最佳锚固参数;风化岩体具有良好的可灌性.实现裂隙灌浆的重点只在于材料性能的确定。笔者认为在此基础上进行保护施工必须综合考虑特定环境条件.充分比较材料的优劣.恰当地选择锚固技术和引用PS及PS复合材料。  相似文献   
13.
锚杆锚固质量安全检测   总被引:3,自引:1,他引:3  
通过对高速公路坡锚杆的无损检测效果分析,锚杆无损检测是公路系统对锚杆锚固安全检测的行之有效的方法。随着今后应用的增多,锚杆的设计和施工进一步接近无损检测条件,声频应力波法将对锚杆锚固质量的无损检测及高速公路的建设提供更可靠的质量保障。  相似文献   
14.
本文介绍了预应力锚杆在衡阳市107国道K8 451~641段边坡加固治理中的应用,其成功地控制了已滑动的山体,避免了滑坡的发展,取得了良好的工程效果.  相似文献   
15.
某热电厂35t/h锅炉脱硫除尘系统技术改造   总被引:1,自引:0,他引:1  
某热电厂尾部烟气的湿法除尘装置存在严重的烟气带水和烟尘排放浓度超标问题,针对上述两个问题,在对原烟气系统进行分析的基础上,进行了技术改造,采用旋流板塔替代原系统的筛板塔,对改造后烟气系统运行测试,结果表明:烟气系统基本上解决了烟气带水和烟尘排放浓度超标问题,同时该装置具备了烟气脱硫功能,在水系统完成后,可以解决烟气脱硫问题。  相似文献   
16.
此文从系统的角度就板料性能、板料毛坯的展开计算、模具设计与制造、摩擦与润滑、应力应变分析等诸多方面对板料成形过程作了一般分析.可知板料成形过程是一复杂的,需要考虑系统中各个因素之间的相互关系和影响才能得到合理的板料成形件.并从有限元法的角度,建立了板料成形过程模型.  相似文献   
17.
Objective: Studies of alcohol-related harm (violence, injury, illness) suggest that the most significant risk factors are the amount of alcohol consumed and whether obviously intoxicated patrons continue to be served. This study's objective was to investigate the effects of a responsible beverage service (RBS)/enhanced alcohol enforcement intervention on bars, bar patrons, and impaired driving.

Method: Two communities—Monroe County, New York, and Cleveland, Ohio—participated in a demonstration program and evaluation. The intervention applied RBS training, targeted enforcement, and corrective actions by law enforcement to a random sample of 10 identified problem bars in each community compared to 10 matched nonintervention problem bars. Data were collected over 3 waves on bar serving practices, bar patron intoxication, drinking and driving, and other alcohol-related harm from intervention and control bars and treatment and comparison communities.

Results: In Monroe County, New York, of the 14 outcome measures analyzed, 7 measures showed statistically significant differences from pre- to postintervention. Six of those measures indicated changes in the desired or positive direction and 2 measures were in the undesired or negative direction. Of note in the positive direction, the percentage of intervention bar patrons who were intoxicated decreased from 44 to 27% and the average blood alcohol concentration of patrons decreased from 0.097 to 0.059 g/dL pre- to postintervention. In Cleveland, Ohio, 6 of the 14 measures showed statistically significant changes pre- to postintervention with 6 in the positive direction and 4 in the negative direction. Of note, the percentage of pseudo-intoxicated patrons denied service in intervention bars increased from 6 to 29%.

Conclusions: Of the 14 outcome measures that were analyzed in each community, most indicated positive changes associated with the intervention, but others showed negative associations. About half of the measures showed no significance, the sample sizes were too small, or the data were unavailable. Therefore, at best, the results of these demonstration programs were mixed. There were, however, some positive indications from the intervention. It appears that when bar managers and owners are aware of the program and its enforcement and when servers are properly trained in RBS, fewer patrons may become intoxicated and greater efforts may be made to deny service to obviously intoxicated patrons. Given that about half of arrested impaired drivers had their last drink at a licensed establishment, widespread implementation of this strategy has the potential to help reduce impaired driving.  相似文献   

18.
The human communities and ecosystems of island and coastal southeast Africa face significant and linked ecological threats. Socioecological conditions of concern to communities, governments, nongovernmental organizations, and researchers include declining agricultural productivity, deforestation, introductions of non-native flora and fauna, coastal erosion and sedimentation, damage to marine environments, illegal fishing, overfishing, waste pollution, salinization of freshwater supplies, and rising energy demands, among others. Human–environment challenges are connected to longer, often ignored, histories of social and ecological dynamics in the region. We argue that these challenges are more effectively understood and addressed within a longer-term historical ecology framework. We reviewed cases from Madagascar, coastal Kenya, and the Zanzibar Archipelago of fisheries, deforestation, and management of human waste to encourage increased engagement among historical ecologists, conservation scientists, and policy makers. These case studies demonstrate that by widening the types and time depths of data sets we used to investigate and address current socioecological challenges, our interpretations of their causes and strategies for their mitigation varied significantly.  相似文献   
19.
船闸布置在江心洲上后,由于相邻建筑物的动水作用及两汊水流在洲尾的交汇,将会影响船闸的通航安全.为研究江心洲型船闸下游的船舶航行问题,探讨有效的改善措施,结合澧水艳洲枢纽、沅水桃源枢纽布置的共同特点,在物理模型基础上利用船舶模型试验分析船闸下游影响航行安全的因素,研究采取针对性措施后航行条件的改善效果.结果表明:布置隔流堤、导流墩等辅助建筑物只能解决下游靠近引航道出口部分航段的通航问题;综合采用拓宽航槽、优化航线、合理调度、优化船闸布置等措施,可有效减小船体漂移,优化航行环境,保障船舶通航安全.  相似文献   
20.
新型高阶Boussinesq方程的一维数值模型及其实验验证   总被引:1,自引:1,他引:0  
基于刘忠波等(2004)推导的新型高阶Boussinesq方程,建立了预报-校正差分格式的数值模型。为考察该数值模型的适用性,针对较大坡度的潜堤上的波浪传播变形进行了数值研究。将数值结果与实验结果进行比较,二者较为吻合,验证了本文的数值模型,同时也说明本方程可用于模拟较陡地形的波浪变形。  相似文献   
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