冶金渣高性能建筑砂浆粉的研制

通过胶砂强度试验,结合技术经济指标,确定出矿渣高性能建筑砂浆粉的最佳配合比。并研究该砂浆粉配制砂浆的性能,主要分析砂浆稠度、分层度、强度等技术指标。结果表明,矿渣高性能建筑砂浆粉可完全取代水泥、石灰膏,配制不同强度标号的砂浆。     

NID半干法脱硫灰制备干粉砂浆的试验研究

研究了水灰比、胶砂比及脱硫灰掺量对砂浆稠度和砂浆强度的影响,结果表明:随着水灰比的提高,砂浆稠度提高,而强度下降;随着胶砂比减小,砂浆稠度降低,而强度提高。试验配比下,脱硫灰掺量为15%~35%时,制备的脱硫灰砂浆28天抗压强度最高60.6 MPa,最低25.4 MPa。最后从微观角度分析了脱硫灰掺入后对砂浆的强度影响。     

环氧砂浆锚固地脚螺栓的施工操作

通过环氧砂浆锚固地脚螺栓的特点，环氧砂浆材料配合比及作用机理等方面谈论环氧砂浆锚固地脚螺栓的施工操作。     

马钢风碎渣制备干粉砂浆技术研究

采用马钢风碎工艺处理的钢渣,替代黄沙制备干粉砂浆。试验结果表明,在DM10的砌筑砂浆中,风碎渣替代黄沙的比例达到60%,同时可加入一定比例的钢渣微粉和粉煤灰,降低水泥用量。砂浆的稠度、分层度、凝结时间、28天抗压强度、干缩率以及安定性等性能指标均符合标准DBJ/T01-73-2003《干拌砂浆应用技术规程》的要求。     

矿山充填砂浆滤水工艺试验研究

如果矿山充填砂浆中多余的水分不能及时排出，会造成充填砂浆分层离析加重和充填体整体质量下降。本文结合金川矿山充填砂浆滤水工艺的研究开发过程，阐述了进路式充填采矿法充填砂浆及时滤水的必要性和研究思路，提出了PDS滤水管L型布置的矿山充填砂浆滤水新工艺。     

影响砂浆流动性能的因素分析

对棒磨砂自流充填系统中砂浆的流动性能进行了现场考察和理论分析,其结果表明影响充填砂浆流动性的主要因素是棒磨砂固体颗粒的粒径和砂浆灰砂比。针对这一情况,结合实际,提出了改善砂浆流动性能的方法。     

超声波作用下尾砂浆浓密沉降及放砂

为了提高砂仓中尾砂浓密效率,实现高浓度的放砂,引入声场作为研究手段,创新性的利用声场辐射方式传播的特性,将声场非接触性地作用于尾砂浆介质中.通过设计试验,配制质量分数为40%的尾砂砂浆,在尾砂浆分别沉降15,20,25,30,35和40 min后,施加频率20 kHz,功率50 W的超声波,探究不同沉降时间后施加超声波作用对最终沉降时间和浓度的影响,同时将超声波作用在砂仓放砂阶段,并对超声波作用后不同浓度的砂浆进行流变参数测定.试验结果表明:在沉降20 min后施加超声波,砂浆沉降浓密时间最短为80 min,尾砂浆最终质量分数可达77.5%,与此同时超声波作用下可以实现砂仓稳定高浓度的放砂,放出砂浆质量分数为74.04%.对比超声波处理前后砂浆黏度与屈服应力可知,超声波可有效降低砂浆黏度22.3%,具有良好的降黏效果.超声波的振动作用,空化作用以及声流效应是使得砂浆快速浓密沉降以及放出的原因.      

基于相场法的砂浆裂纹相互作用失效分析

提出一种新的基于相场法的砂浆断裂力学分析方法,对裂纹相互作用导致的砂浆试件失效行为进行模拟分析.采用非保守Allen-Cahn方程作为控制方程,借助COMSOL有限元分析软件,将线弹性力场和相场整合为统一的有限元模型,对砂浆中裂纹发展和相互作用进行模拟分析.通过砂浆三点弯曲试验和直拉试验,测试砂浆裂纹扩展过程.模拟结果与试验结果的对比分析表明,砂浆试件裂纹相互作用临界荷载的模拟计算结果与试验结果非常吻合.研究结果表明,Ⅱ型试件断裂破坏会产生更长的裂缝路径.      

干混砂浆促进建筑业低碳节能发展概述

本文重点从品质稳定,种类齐全,质量优越,利废环保等几个方面介绍了干混砂浆的特点。并说明了它的社会经济效益,推广利用干混砂浆将对建筑业低碳节能发展起到有力的促进作用,并对干混砂浆良好的发展前景进行了展望。     

浅谈环氧砂浆铆固地脚螺栓施工技术

详细介绍了环氧砂浆组成材料的性能，影响其强度的主要因素以及环氧砂浆铆固地脚螺栓的施工程序，并提出几点注意事项。     

ICP-AES法测定稀土金属中的钛、钼、钨、铌和钽

针对试样特点拟定了加大称样量以减轻偏析,以浓硝酸溶解样品破坏碳化物,加入氢氟酸助溶,分离稀土基体同时络合钛、钼、钨、铌和钽的方法,无须基底匹配,采用工作曲线法成功地测定了金属镧、铈、镨、钕、钐、铕、钆、铽、镝、钇中的钛、钼、钨、铌和钽量,测定范围:0.0050%～0.50%。     

混凝土强度等级的验收与评定

结合现行相关规范和实际施工操作的一些经验,对混凝土试件的制作、养护、强度计算及验收评定阐述了混凝土强度的验收与评定,对于施工阶段混凝土强度的评定,应根据混凝土的结构跨度、类型、模板位置等来评定,采用的方法有两种:一种是统计法,另一种是非统计法供施工企业参考应用。     

延长碳化时间对焦炭性能的影响

为了研究延长碳化时间对焦炭质量的影响，通过对焦炭块度、冷热强度和气孔率等指标进行宏观分析，并且从焦炭显微结构微观角度分析延长碳化时间对焦炭内部结构的改变。结果表明，随着碳化时间的延长，焦炭中的镶嵌组织逐渐增多，光学组织之间有很好的结合性，减少了裂纹的发生，阻止了裂纹的延展;焦炭的块度大幅提高，冷热性能均有所改善，孔径和气孔率都有所降低，焦炭的反应性降低。     

Evaluation of the Water Delivery Performance of the Menemen Left Bank Irrigation System Using Variables Measured On-Site

This study determines the water delivery performance at secondary and tertiary canal level of the Menemen Left Bank Irrigation system, an open canal irrigation system located in Turkey, for the irrigation seasons of the years 2005–2007. At secondary canal level, water supply ratio was used, and at tertiary level, the indicators of adequacy, efficiency, dependability, and equity were used. In calculating these indicators in this study, the amounts of water diverted to the canals, efficiency of water conveyance, and of water application were measured. Of these indicators, the water supply ratio was determined for the secondary canal, and the other indicators were determined for a total of six selected tertiary canals at the head, middle, and lower end of the secondary. At secondary level, the water supply ratios obtained to total irrigation water requirements for the months of July and August, when requirement for irrigation water is at a maximum, was determined to be less than one, while the water supply ratios obtained to net irrigation water requirement was found to be more than one. With regard to water delivery performance at tertiary level, adequacy, efficiency, dependability, and equity were found to be poor for each of the three years of the study, with efficiency rising to “fair” level only in 2005. In order to raise the water delivery performance of the system, it is necessary to reduce water conveyance losses to increase the water application efficiency, to prepare water distribution plans which take in tertiary canals, and to measure and monitor the water diverted to the canals.     

转炉底吹供气方式对熔池混匀效果的数值模拟

通过数值模拟的手段,以北方某钢厂300 t转炉为原型,建立了转炉底吹的三维模型。研究了在非均匀供气制度下转炉底吹氩气对转炉混匀效果的影响,优化了设计方案。结果表明,随着底吹氩气流量的增加,熔池内平均流速和平均湍动能均增加,弱流区比例减小,但死区比例降低的幅度不大。单个透气砖氩气流量为440 m3/h时,流量分配比为1∶1、2∶1、3∶1和4∶1的平均速度分别0.189、0.204、0.167和0.168 m/s,死区比例分别为17.5%、11.60%、23.53%和20.23%。流量分配比为2∶1时转炉混匀效果最好,1∶1时次之,4∶1时再次,分配比为3∶1时混匀效果最差。     

高碱高钙介质黄铁矿抑制及铵盐活化机理的现状与展望

文章主要介绍了黄铁矿在高碱高钙介质中被抑制的机理及铵盐对其活化机理,CaO、Ca(0H)+、CaS04、Ca(OH)2、Fe( OH)2 、Fe( OH)3、Fe2(SO4)3、Fe2 (SO4)3 ·9H2O、FeSO4、FeS04·7H2O等亲水性物质罩盖在黄铁矿表面使其表面亲水;而铵盐活化黄铁矿的机理体现在适当降...     

Theoretical Model of Shield Behavior During Excavation. I: Theory

Closed-type shield tunneling methods were developed together with computer-aided automatic control systems. However, automatic control systems are based on empirical relationships and do not have a precise theoretical background. In this paper, a model of the theoretical dynamic load acting on the shield during excavation is developed, taking into account shield tunnel engineering practices; i.e., the excavated area, the tail clearance, the rotation direction of the cutter face, sliding of the shield, ground loosening at the shield crown, and the dynamic equilibrium condition. To evaluate the validity of the model qualitatively, the simulation of shield behavior and the sensitivity analysis of the model parameters on the shield behavior are carried out in both straight and curve alignments for both sandy and clayey ground. The results for the shield behavior are examined, comparing them with the empirical and the theoretical one, and it is confirmed that the proposed model represents the shield behavior reasonably well.     

Ain’t necessarily so: Review and critique of recent meta-analyses of behavioral medicine interventions in health psychology.

Objective: We examined four meta-analyses of behavioral interventions for adults (Dixon, Keefe, Scipio, Perri, & Abernethy, 2007; Hoffman, Papas, Chatkoff, & Kerns, 2007; Irwin, Cole, & Nicassio, 2006; and Jacobsen, Donovan, Vadaparampil, & Small, 2007) that have appeared in the Evidence Based Treatment Reviews section of Health Psychology. Design: Narrative review. Main Outcome Measures: We applied the following criteria to each meta-analysis: (1) whether each meta-analysis was described accurately, adequately, and transparently in the article; (2) whether there was an adequate attempt to deal with methodological quality of the original trials; (3) the extent to which the meta-analysis depended on small, underpowered studies; and (4) the extent to which the meta-analysis provided valid and useful evidence-based recommendations. Results: Across the four meta-analyses, we identified substantial problems with the transparency and completeness with which these meta-analyses were reported, as well as a dependence on small, underpowered trials of generally poor quality. Conclusion: Results of our exercise raise questions about the clinical validity and utility of the conclusions of these meta-analyses. Results should serve as a wake up call to prospective authors, reviewers, and end-users of meta-analyses now appearing in the literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

城市垃圾焚烧飞灰添加到烧结工艺的影响

垃圾焚烧飞灰为城市垃圾焚烧烟气净化系统和余热回收系统中收集而得到的残余物,其产生量约为垃圾焚烧量的3%~10%。因为飞灰中含有多种重金属和二噁英而被列为危险废物。本试验将焚烧飞灰添加到铁矿石烧结工艺中,研究了飞灰的添加对烧结工艺的影响。烧结试验结果表明,添加飞灰后,提高了残留在烧结矿中的Cl、S、K和Na等元素的含量,烧结成品率有所下降,转鼓指数略有变化;但添加飞灰后,烧结矿成品的还原强度指数、低温还原粉化指数、耐磨指数等指标有明显的提高。同时,添加飞灰烧结后,烧结尾气中的二噁英、SO₂、Cl、K、Na等元素含量也明显增加。     

东沟特大型钼矿床矿石物质组成及选矿新工艺

通过对河南汝阳东沟特大型钼矿床矿石物质组成及选矿新工艺的论证评价。揭示了该矿床物质成分的复杂性及选矿性能，得出以下认识：1）赋矿岩石以碳酸盐与铝硅酸盐为主要组分，受后期构造热液影响，矿石破裂变形、扭曲以及交代现象十分普遍，因而矿石具多种复杂结构，这些因素可对矿石的选矿性产生严重影响；2）对选矿方案给予多方面论证，找出了矿石技术加工的难点及影响因素，并在选别过程中给予了充分考虑；3）可浮性试验。找出脉石矿物上浮所需时间及与目的矿物之间的关系；4）粗选试验，从七个方面对目的矿物的捕收剂及其用量和添加地点、磨段细度、脱泥考察、石英和硅酸钠用量等都进行了全面试验，并找出各方面适应矿石物质组成和选矿性能的楔合点，给出了一系列参数作为依据；5）钼精选试验，分别进行了再磨细度、抑制剂种类、全开路和浮选闭路流程等四方面试验，使最终产品的选别指标满足国家标准。结论：浮选使用70％-200目，再磨设置在83．5％-400目条件下，选用磷诺克斯与巯基乙酸钠配合，有效地抑制了黄铜矿、方铅矿等硫化物杂质的混入，再次精选获得钼精矿品位51．08％，钼回收率84．24％，达GB3200-82特级品标准。