孤岛工作面回采巷道支护参数优化研究

对21072孤岛工作面支承压力影响因素进行了分析,根据孤岛煤柱内巷道压力分布规律和煤层柱状图设计建立了计算机数值模型,通过计算机模拟计算得出锚网支护参数优化结果.     

高水充填材料的反应机理

本文介绍了由硫酸盐水泥熟料,超缓凝剂和适量悬浮剂混合而成的高水充填材料的化学成份及其反应过程。     

岩石工程的理论与实践(三)

非弹性特性图16表示了在地下岩石开挖工程周围可能出现的岩体非弹性响应的一些类型,这包括岩石材料的剪切和张裂破坏〔50〕,塑性变形带的形成〔3、13〕,不连续面的滑移〔21、51〕,相互接触的岩块的局部破     

'EUROPART'. Airborne particles in the indoor environment. A European interdisciplinary review of scientific evidence on associations between exposure to particles in buildings and health effects

The relevance of particle mass, surface area or number concentration as risk indicators for health effects in non-industrial buildings has been assessed by a European interdisciplinary group of researchers (called EUROPART) by reviewing papers identified in Medline, Toxline, and OSH. Studies dealing with dermal effects or cancer or specifically addressing environmental tobacco smoke, house dust-mite, cockroach or animal allergens, microorganisms and pesticides were excluded. A total of 70 papers were reviewed, and eight were identified for the final review: Five experimental studies involving mainly healthy subjects, two cross-sectional office studies and one longitudinal study among elderly on cardiovascular effects. From most studies, no definite conclusions could be drawn. Overall, the group concluded that there is inadequate scientific evidence that airborne, indoor particulate mass or number concentrations can be used as generally applicable risk indicators of health effects in non-industrial buildings and consequently that there is inadequate scientific evidence for establishing limit values or guidelines for particulate mass or number concentrations.     

City size distributions and spatial economic change

"The concept of the city size distribution is criticized for its lack of consideration of the effects of interurban interdependencies on the growth of cities. Theoretical justifications for the rank-size relationship have the same shortcomings, and an empirical study reveals that there is little correlation between deviations from rank-size distributions and national economic and social characteristics. Thus arguments suggesting a close correspondence between city size distributions and the level of development of a country, irrespective of intranational variations in city location and socioeconomic characteristics, seem to have little foundation." (summary in FRE, ITA, JPN, )     

建筑物表面起霜的原因及防治措施

建筑物表面易产生一种白色物质,俗称“起霜”,日本称为“白华”,英文名称是efflorescence。白霜主要是一些无机盐类从溶液中析出的结晶,它产生体积膨胀,造成结晶膨胀压力,导致装饰层与基层脱离。白霜的机械强度很低,也是导致装饰层与基层粘结不良的原因之一。混凝土工程使用N2SO4或者以Na2SO4为主要组分的复合产品作为早强剂,增加了形成白霜的可溶性盐类,且硫酸钠在低温下溶解度较低,明显地增大混凝土表面析出白霜的可能性。     

危难之时见深情

最近，在豫西南的镇平县，人们纷纷传颂着县消防中队的党员们慷慨解囊、扶危救难的佳话。那是在2月28日夜，天气乍暖还寒，因公外出归来的镇平县消防中队指导员郝卫军、司务长张建设、专业警士吴会云3人乘车来到了工业南路西段，借着昏暗的灯光，他们猛然发现前面路边的沟里人影晃动，情况异常。于是，武警官兵高度的责任感使他们立即把车停下，上前察看。原来，在十几分钟以前，这里发生了一起车祸，一名骑自行车的外地人被镇平县某单位的一辆“上海”牌小轿车撞伤，躺在地上起不来，轿车也冲进沟里。而那位年轻的肇事司机非担不及时将伤者…     

高层建筑设备安装监理事前控制初探

1事前控制与预控方向一般地讲，现行的建筑安装工程施工及验收规范，基本上属于事中、事后控制的范畴（对土建要求）。对于建筑采暖卫生与煤气安装工程、建筑电气安装工程、通风与空调工程、电梯安装等建筑设备安装的事前控制目前尚无一个定性或约定成俗的规则，这无疑给设备安装专业监理的实际操作带来一定的难度。作为监理方，接受业主的委托，理应更进一步地做好领控工作。所谓预控，既要进行超前部署、又需进行主动协调管理。高层建筑设备面广量大、技术先进、功能复杂、专业齐全，应当注意监理工作的事前控制，自始至终控制好设备安装…     

A novel multi-electrode system for electrolytic and biological water treatments: electric charge transfer and application to denitrification

A novel multi-electrode system is proposed for electrolytic and biological water treatments. The multi-electrode system is comprised of multiple working electrodes and their counter electrode, where electric current or potential applied to each electrode is controlled independently. Experimental result for different electrolyte solutions showed that electric charge in the system was efficiently carried by dissociative electrolytes such as carbonate ions. This transfer mechanism is regarded as being effective both in keeping pH level around neutrality and in passing certain amounts of electric current especially in dilute solutions such as groundwater and surface water. A long-term (over 500 days) experiment also showed the enhanced and stable denitrification performance of biofilm-electrode reactor (BER) equipped with the multi-electrode system, comparing to former BERs. This superior performance was thought to be attributable to large effective surface area of electrode, the charge transfer mechanism by dissociative electrolyte, and the formation of highly reducing (or oxidizing) zones. From these results, we conclude that the multi-electrode system is useful for electrolytic and biological treatments of groundwater and surface water.     

冷却速率对水泥性能的影响综述

引言: 熟料在冷却机中的最佳冷却速率对于节能,提高熟料质量,降低扬尘,尤其在使用低品位原料上特别重要。本文评述印度水泥工业熟料冷却的现状,比较工业生产所用的各种冷却工艺,并讨论其影响结果。 水泥工业所用的冷却机种类: 出窑熟料(1200°～1250℃)需要冷却到最低温度,这是由于:(a)输送困难,