自密实混凝土强度尺寸效应的试验与数值仿真

自密实混凝土(SCC)是通过掺加高效减水剂而得到的流动性极佳的混凝土,具有很高的流动性,不离析、不泌水,无须振捣便可达到自密实的效果.本文对边长为70.7mm的立方体小试件在不同边界条件下进行单轴压缩试验,用以研究端部效应对SCC强度及破坏形态的影响.为了避免端部效应对尺寸效应的影响,本文考虑减摩措施,对边长为70.7mm、100mm、150mm、200mm、300mm立方体SCC试件进行单轴压缩试验,试验结果表明,随着试件尺寸的增加,混凝土的单轴抗压强度不断减低,即呈现出明显的尺寸效应现象,符合Weibull强度统计理论.此外,基于混凝土细观概率模型进行相应的数值仿真,通过对比数值模拟结果与试验结果,验证了该模型能较好地模拟混凝土尺寸效应现象.     

新型过滤车间配置在铝土矿选矿中的应用

长期以来,我国铝土矿选矿企业过滤车间通常采用两段配置,这种配置方法存在着投资高、占地面积大等缺点。本文阐述了一种新型的过滤车间配置结构,并通过技术经济比较分析了此种新型配置结构的优势及特点。     

纤维缠绕压力容器表面损伤试验研究

通过制作纤维缠绕标准容器试样,并对部分试样表面纤维制作人工损伤,与标准容器试样比较爆破压力,并进行有限元分析、研究其破坏机理,对强度影响程度进行评估。结果表明：表面纤维损伤会造成压力容器在应力水平较低情况下局部发生层间剪切破坏,损伤容器爆破强度平均值降低22．4％,损伤修复后的容器爆破强度降低12．2％。     

棉花西瓜间套种植模式的探讨

总结了永济市卿头镇杜家营村多年棉、瓜间套高效种植模式的主要技术,分析了该村棉、瓜间套模式的经济效益,提出了因地制宜推广棉瓜间作、提高棉田种植效益的相关建议。     

运城棉花产业发展对策与建议

重点分析了山西省棉花主产区运城市2012年的棉花生产特点,分析了近几年棉花种植面积滑坡的主要原因,并有针对性地提出了运城市棉花产业稳定发展的对策与建议。     

Study on the material character steel big-end bolt

Based on the manufacturing method now used in our country, caused low bearing capacity in the bolt-end, which is a potential danger in the bolt supporting tunnel and a waste of money, and presented the new type strong steel big-end bolt can solve this problem. Analyzed the active state of the end of bolt by ANSYS, we can know that it is very disadvantage when bolt bore eccentric load. Contrasted with the different that common bolt and big-end bolt when they bore the same loading. The common bolt is bigger than the big-end bolt in stress value. Study on the processing technic of the new type of the strong steel big-end bolt, the new metal big-end bolt was produced by heat processing over big-end bolt and upset. From the microscopic examination on bolt metal, it is concluded that heat processing on the bolt-end refines the crystal grain of the metal material, which not only increase its extension but improve its property. Moreover the strength ability of the bolt material can be exerted completely.     

水平低周反复荷载作用下高效预应力叠合框架抗震性能的试 …

介绍了两榀高效预应力混凝土（ＨＰＣ）叠合框架和１榀（ＲＣ）整浇框架模型试验,并对试验结果进行了比较。分析了ＨＰＣ叠合框架在水平低周反复荷载作用下的受力特点、裂缝开展、延性指标、耗能能力及破坏形式,为ＨＰＣ叠合框架结构在地震区的应用提供了试验依据。     

榆家梁煤矿巷道围岩松动圈测试技术及应用

基于榆家梁煤矿现场条件,介绍了松动圈的测试原理、测试方法及测试过程,通过测试得出了围岩合理的松动圈范围,为确定合理锚杆支护参数提供了依据,为相似条件巷道的松动圈测试提供了实践经验.并介绍了控制松动圈厚度的方法,对井下支护设计具有借鉴意义.     

Temporal evolution of atmospheric cascade glow discharge with pulsed discharge and radio frequency discharge

Atmospheric cascade discharges with pulsed discharge and radio frequency(RF)discharge were experimentally investigated by the temporal evolution of discharge spatial profile and intensity.The indium tin oxide(ITO)coated glass was employed as the transparent electrode to capture the discharge distribution above the electrode surface.It is demonstrated that in the pulsed discharge with dielectric barrier,the first discharge at the rising edge of pulse voltage is uniformly ignited and then forms an expanding plasma ring on the ITO electrode surface,which shrinks to the same diameter as that of bare stainless steel electrode with the generation of second discharge at the falling edge of pulse voltage.The discharge profiles along the electrode surface and discharge gap of the successive RF discharge are dependent on the intensity and spatial distribution of residual plasma species generated by the pulsed discharge,which is determined by the time interval between the pulsed discharge and RF discharge.It is demonstrated that the residual plasma species before the RF discharge ignition help to achieve the stable operation of RF discharge with elevated intensity.