Diffusion characteristic of sulfate anion in surface region of cement mortar at early stage

The SO_4~(2-)concentration distributions in surface region of cement mortar immersed in sulfate solution at early stage were measured by layered sampling method combined with chemical analysis, and the diffusion coefficients of SO_4~(2-)anions in surface region of mortar into internal area were calculated by means of instantaneous plane diffusion theory. The experimental results showed that the SO_4~(2-)concentration gradually reduced when the diffusion depth increased in the surface region of mortar. Diffusion coefficient(D) was relevant with the concentration and kind of environmental sulfate solution, which reduced with immersion time at the beginning, and then rose slowly after a period of time. The calculation of initial diffusion coefficient(D_0) and starting time of deterioration(t_∞) caused by sulfate attack was further attempted based on the data of diffusion coefficient, and it was found that D_0 and t∞ were all relevant with concentrations of sulfate and different kind of sulfate as well.     

直动式水压溢流阀的动态特性分析与试验

介绍了一种直动式水压溢流阀的结构原理和特点,建立了动态特性的数学模型,并对其动态特性进行了仿真.仿真结果表明:在阀心尾端设置阻尼腔可有效改善溢流阀的动态性能.通过试验证明,所研制的水压溢流阀具有良好的静态和动态性能.     

地表超高渣堆对井下巷道稳定性的影响研究

The continuous growth of the height of the coal mine surface slag heap will make the stress size and distribution characteristics of the surrounding rock of the underground roadway under it change significantly, which will seriously lead to large deformation or damage of the roadway, and affect the safe and efficient production of the mine. Based on the geological occurrence conditions of coal strata, mining production and the actual situation of surface super-high slag pile in Wuhushan Coal Mine, a threedimensional model of surface slag pile and underground mining face in Wuhushan Coal Mine is established. The characteristic parameters of roadway surrounding rock stress peak value and location, mining influence range under different slag pile heights have been simulated and calculated, and then the influence law of different slag pile height on roadway stability is analyzed. Combined with the measured data of roadway deformation, the safety critical height of the surface slag pile is initially determined. The research results have important reference value for the safe and efficient production of similar mines.     

先导式水压溢流阀动态特性的仿真

对一种新型的先导式水压溢流阀进行了动态特性的建模和仿真研究,分析了多种因素对溢流阀动态特性的影响。仿真结果表明,先导阀尾端设置阻尼腔有利于提高先导阀的工作稳定性;在主阀口前设置合适的节流孔可降低主阀口的工作压差,减小阀口的气蚀,提高溢流阀的工作性能和使用寿命;主阀心上腔容积V12、先导阀入口容积V2、溢流阀入口容积V0对溢流阀的动态特性均有较大影响。     

成品内保温风管在城市副中心剧院项目中的应用

探讨场外预制化成品内保温风管、场内吊装的新施工工艺,将传统镀锌钢板风管制作、风管保温、风管隔热、风管防火包覆等工序场外集成预制,形成成品内保温风管,风管进场后直接吊装,极大减少了高大空间频繁登高作用的降效、密集竖井及紧凑机房内无安装空间的质量失控,有效减少了通风工程施工绝对工期时长并显著去除了风管安装缺连接件、漏做保温等质量通病。     

开区注液氮防灭火技术在羊场湾煤矿的研究与应用

 羊场湾煤矿所采煤层自然发火等级为Ⅰ级,属于易自燃煤层,最短自然发火周期仅为23天。因此,煤层自然发火严重威胁着羊场湾煤矿的安全生产。在大采高综采工作面回采区间,通过实施开区注液氮防灭火技术后,有效地降低了采空区内温度和CO浓度,取得良好的防火效果。     

八流T形连铸中间包钢水停留时间分布特征研究

基于相似原理,建立了八流连铸中间包的1∶2物理模型,通过水模实验测定了1#～4#控流方案下中间包内的停留时间分布(Residence time distribution,简称RTD).通过推导提出了多流连铸中间包的RTD曲线分析方法,并以此分析了中间包内的流体平均停留时间、流动模式和各流流动一致性,进而对控流装置进行优化选择.研究结果表明,3#控流方案能较好地改善中间包内的流动特征.     

2005年冶金工业与环境保护论坛在京召开

2005年中国冶金工业环境保护论坛暨中华环境保护基金会冶金工业环境保护宣传专项基金工作年会,12月3日在北京人民大会堂隆重召开。全国政协副主席阿不来提·阿不都热西提,原全国人大常委会副委员长布赫等领导到会祝贺。首钢总公司、中国冶金建设集团公司、山西城财焦化集团公司等100多家冶金及相关产业企业的领导(代表),新华社、《人民日报》、《光明日报》、《经济日报》、中央电视台等50多家中央新闻单位记者参加了会议。     

大圆坯结晶器电磁搅拌器磁场的数值模拟

基于有限元方法,利用ANSYS软件模拟计算了大圆坯连铸结晶器电磁搅拌(M-EMS)器内三维磁场分布,分析了铜管厚度、断面和搅拌电流、频率对磁场分布的定量影响,并通过磁场的实验测定对数学模型进行了验证.研究表明,磁场模拟结果与实测结果吻合得较好;结晶器铜管对磁场具有较强的屏蔽作用,铜管越厚,屏蔽作用越强;小断面结晶器内磁感应强度大于大断面的情况;磁感应强度随着频率的增大而减小,随电流的增大而增大.