石英质捣打料的烧结性能研究

以大容量中频炉用石英质捣打料为对象,研究在不同烧结温度、添加不同含量促烧剂条件下烧结捣打料的性能。结果表明,石英平均晶粒度为550μm;α-磷石英向α-方石英的相变温度约为1250℃;随着促烧剂含量的增加,1100℃烧结试样的线变化率总体呈增大趋势,1600℃烧结试样的线变化率先增大后减小,试样的显气孔率总体呈降低趋势,捣打料的耐压强度均随促烧剂含量的增加而逐渐增大;促烧剂对捣打料中温烧结强度影响明显,其高温烧结则主要依赖于石英粉体。     

水泥浆体的微结构及其与强度的关系

在亚微观尺度上描述了水泥石的微结构，简要回顾了其研究进程，详细介绍了主要水化产物以及掺加不同混合材可改变水化产物组分含量。归纳了水泥石的微观结构与强度的关系，并展望了其研究前景。     

Characterization of nickel-bearing ferrites obtained as by-products of hydrochemical wastewater purification processes

The efficiency of the ‘ferrite process’ for the purification of wastewater heavily contaminated with nickel is evaluated, and the solid residues formed are characterised. The efficiency of the purification process is always above 99.9% for Fe²⁺/Ni²⁺ ratios greater than 3. The tested Fe²⁺/Ni²⁺ molar ratios (15/1, 7/1 and 3/1) yielded three different nickel ferrites. Inductively-coupled plasma atomic emission spectroscopy (ICP-AES), potentiometric titration, X-ray fluorescence (XRF), X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) yielded Ni_xFe_1−x^IIFe₂^IIIO₄ (x=0.18, 0.40 and 0.65, respectively) as the most probable stoichiometry, and inverse spinel as the most probable structure. Heating at 600 °C causes the transformation of the solids into a mixture of NiFe₂O₄, α-Fe₂O₃ and NiO. Electrochemical analysis of the solid nickel ferrites was performed using carbon paste electrodes (CPEs) in HClO₄ and HCl media. In each case, the first cyclic voltammogram showed the participation of solid species in the electrochemical transformation process, since the shape of the redox peaks could be related to the structure and stoichiometry of the ferrites. In second and successive scans, the voltammograms indicated the redox couples Fe_ads³⁺+1e⁻⇔Fe_ads²⁺ (0.525 V vs. Ag/AgCl) and Ni_ads²⁺+2e⁻⇔Ni(s) (−0.470 V) in HClO₄, and FeCl_2,ads⁺+1e⁻⇔FeCl_ads⁺+Cl⁻ (0.475 V) and NiCl_x,ads^(x−2)−+2e⁻⇔Ni(s)+xCl⁻ (−0.550 V) in HCl.     

木素磺酸钙对水泥净浆的缓凝机理研究

研究了掺加木素磺酸钙(简称木钙)后水泥净浆液相中钙离子、硫酸根离子和氢氧根离子浓度随水化时间的变化,以及除糖后木素磺酸钙对水泥净浆凝结时间的影响．结果表明,掺加木钙后在水化初期水泥净浆中S042-浓度大幅度上升,OH-浓度变化不大．木钙掺量越大,水泥净浆中游离Ca2 浓度的峰值出现越迟,浆体的初凝时间越长．进一步研究发现木钙的掺加能促进熟料矿物的水解,当木钙掺量为0．5％(质量分数)时,水泥净浆中的总Ca2 浓度峰值比未掺加木钙时增加48％,被络合的Ca2 量峰值较水化开始时增加2倍．在水泥净浆强碱性溶液中木钙的络合能力增强导致Ca(OH)2不能达到过饱和,是造成水泥净浆缓凝的重要原因,木钙对水泥净浆的缓凝机理为“吸附-络合”机理．     

电子浆料用超微细玻璃粉的等离子体改性

以六甲基二硅氧烷为单体,利用高频等离子体在超微细低熔磷酸盐玻璃粉体表面聚合硅氧聚合物包覆薄膜。用水和粉体压片之间的接触角变化表征了等离子体工艺参数对粉体表面能的影响。结果表明改性后粉体配制电子浆料的细度、黏度、流变特性提高显著。改性后可以改变或控制超微细粉体的表面能大小,从而可调节电子浆料的流变性和印刷适性。     

顶管技术在输电工程施工中的应用

本文对顶管技术进行了介绍和和讨论，供同类工程施工参考     

Influence of ultra-fine fly ash on hydration shrinkage of cement paste

1INTRODUCTION Hydrationshrinkageisalsoknownaschemicalshrinkage[1].Thesolidvolumeincreasesafterce menthydrating,buttheabsolutevolumeofcementwatersystemreduces.Usuallythetotalamountofvolumeshrinkageofcementwatersystemis7%9%[1,2].Withthedevelopmentofthetechno logyofcementandconcrete,concretewithhighstrengthandhighperformanceisthedevelopingtendencynow.However,nowadays,comparedwithordinaryconcrete,thehydrationshrinkageofhighperformancecementconcreteincreasesobvi ouslybecauseoftheaccelerationof…     

蒙太奇网格融合

三维物体融合是一种新的几何造型方法,它利用三维模型之间的剪贴操作从两个或多个现有的几何模型中光滑融合出新的几何模型.提出了一种基于局部调和映射的三维网格蒙太奇融合新方法.首先利用网格上的近似等距线算法来抽取出待融合区域,然后对两个待融合区域进行带内孔的调和映射参数化,最后通过拓扑合并和融合控制来实现网格的光滑融合.与原有的基于全局调和映射的融合方法相比,新方法的算法效率大幅度提升,求解时间不再随融合模型顶点数的增加而呈指数增长;减少了二维网格拓扑合并中奇异情况出现的概率,提高了算法的稳定性;被剪切网格的细节得到完整保留;消除了原算法对融合区域拓扑的限制.实验结果表明,此方法可以用来生成许多三维动画中的特殊夸张造型效果,在影视动画中具有应用价值.     

Experimental design with fuzzy levels

A novel technique is introduced for planning experimental design employing fuzzy rule-based systems. The significant aspect of the proposed experimental design with fuzzy levels (EDFL) is assigning a membership function for each level of variable factors. Consequently, the design matrix and observed responses can be represented in a set of fuzzy rules. Several examples are presented to clarify the proposed idea and the results are compared with the conventional Taguchi methodology. We have specifically planned an L18 orthogonal array EDFL for the solder paste printing stage of surface mount printed circuit board assembly to provide a model for the process and to optimize the selection of variable factors.     

适合铝丝键合后热老化要求的金导体浆料

研究了一种适合铝丝键合后热老化要求的金导体浆料，性能达到使用要求。在金浆中添加了少量合金元素，并选用混合型粘结剂。对金导体铝丝焊后热老化失效机理以及添加合金元素的作用，进行了讨论