三门峡地区黄土工程特性

三门峡地区广泛分布第四纪黄土及黄土状土,通过分析该地区黄土的颗粒成分、矿物成分、化学成分、微观结构特征,分析了黄土的工程特性,结果表明:该地区Q3黄土的组成与中更新统黄土的矿物组成基本相近,颗粒组成以粉粒为主,黏粒含量大于我国西北地区,粉粒含量小于西北地区;全新统黄土、晚更新统黄土为中等、强湿陷性黄土,湿陷性系数为0.020~0.098,中更新统黄土一般不具有湿陷性。     

粉土界面恒刚度循环剪切试验研究

竖向循环荷载作用下桩土界面的作用机理是研究桩土摩擦疲劳的关键。针对循环荷载作用下桩-粉土界面的剪切性能,使用改进的剪切试验装置在恒刚度条件下进行循环剪切试验,研究循环次数、累积位移和法向刚度对其摩擦疲劳性能、循环后单调剪切性能的影响。试验结果表明,粉土在循环剪切过程中,法向应力和剪应力在初始10个循环内随循环数增加快速衰减,随着循环进行,逐渐趋于稳定;单次循环内在剪切位移方向变化时,土体呈现表现出剪缩-剪胀-剪缩交替现象,总体变形呈现剪缩的趋势;循环荷载作用下,粉土界面的法向应力和剪应力随法向刚度增大衰减速率增大,达到稳定的累积循环位移越小;粉土循环后的单调剪切、法向应力恢复的单调剪切的剪应力比小于首次单调剪切试验值,且法向应力恢复的循环后剪切试验的剪胀程度较小,表明循环剪切过程中界面处粉土颗粒棱角破碎,颗粒变得光滑。在对试验数据分析的基础上,提出了与累积位移、法向刚度和初始应力相关的无量纲累积位移,建立了法向应力和界面摩擦角随累积位移的衰减方程。     

客运船闸游客过闸等待时间的计算分析

船闸的通过能力是船闸工程的一项重要技术经济指标,杭州市胜利河船闸作为旅游用客运船闸,对游客过闸等待时间提出了较高的要求.船闸设计人员根据初定的游客过闸等候时间目标,将其分解到船闸运行的各个步骤,由此反推输水系统的结构参数,根据选定的输水系统型式进行闸室灌泄水时间计算和闸门启闭设备的选型,进行船闸工作门启闭时间的计算等.实际运行证明,该方法达到了预定设计目标.     

土耳其盐穴地下储气库大井眼钻井技术

土耳其Tuz G?lü盐矿区拟建造地下天然气储气库,存在2个可能性风险:矿床实际深度与原计划钻探深度的偏离;钻井与建腔过程中侵出CO2气体,因此该气库建造存在一定的地质及工程风险。为加快该项目进展,满足盐穴储气库钻井要求,通过优化方案采用国内没有应用过的生产套管大尺寸井眼井身结构,采用液压扩孔器扩眼,并形成钻井配套技术。文中从井身结构、钻头优选及螺杆钻具应用、钻井液体系优选、固井以及钻探效果等方面,阐述Tuz G?lü天然气地下储气库钻井技术。通过实施,有效降低了钻井事故复杂时率、缩短钻井周期,机械钻速得到提高,取得了显著的经济效益。     

华润矿综放工作面顶煤放出率提升措施的探究

为促进华润矿煤炭开采效率的进一步提升,对华润矿综放面顶煤放出率提升措施展开探究,从预先爆破、支架优化、放煤工艺优化、加强工作面初末采及上下端头顶煤回收四个方面作出理论分析.     

Eu@C86 isomers: Calculated relative populations

Abstract

Relative populations of four energy-lowest IPR (isolated-pentagon-rule) isomers of Eu@C₈₆ are computed using the Gibbs energy based on characteristics from density functional theory calculations (M06-2X/3-21G?～?SDD entropy term, M06-2X/6-31G*～SDD or B2PLYP(D)/6-31G*～SDD energetics). The calculations confirm that the recently isolated Eu@C₁(7)-C₈₆ species is a major isomer in a relevant temperature region. Relationship to the empty C₈₆ cages is discussed, too.     

Development of mobile miniature natural gas liquefiers

With increasing consumption of natural gas (NG), small NG reservoirs, such as coalbed methane and oil field associated gas, have recently drawn significant attention. Owing to their special characteristics (e.g., scattered distribution and small output), small-scale NG liquefiers are highly required. Similarly, the mixed refrigerant cycle (MRC) is suitable for small-scale liquefaction systems due to its moderate complexity and power consumption. In consideration of the above, this paper reviews the development of mobile miniature NG liquefiers in Technical Institute of Physics and Chemistry (TIPC), China. To effectively liquefy the scattered NG and overcome the drawbacks of existing technologies, three main improvements, i.e., low-pressure MRC process driven by oil-lubricated screw compressor, compact cold box with the new designed heat exchangers, and standardized equipment manufacturing and integrated process technology have been made. The development pattern of “rapid cluster application and flexible liquefaction center” has been eventually proposed. The small-scale NG liquefier developed by TIPC has reached a minimum liquefaction power consumption of about 0.35 kW·h/Nm³. It is suitable to exploit small remote gas reserves which can also be used in boil-off gas reliquefaction and distributed peak-shaving of pipe networks.     

可调偏迈步式胶带自移机尾的研究

随着掘进工作面自动化程度的提高,掘进巷道速度也在日益加快,而现有的顺槽皮带机机尾移动缓慢且移动时工作量大,需要两三人配合操作,存在一定的安全隐患。针对以上问题,研发可调偏迈步式胶带自移机尾,具有与悬挂二运皮带转载机搭接行程长,可以迈步式前进,自动调偏等功能,同时,可以降低工人的劳动强度,加快巷道掘进速度。