微磨具磨削钠钙玻璃的磨损机理实验研究

建立了微磨削过程中单颗磨粒的磨损数学模型,通过观测微磨具磨削前后直径变化、表面形貌变化及加工前后试件的表面质量,分析了微磨削过程中不同阶段磨粒的磨损情况.利用粒度500~#微磨具对钠钙玻璃进行单因素磨损实验,研究不同的磨削影响因素对微磨具磨损的影响规律.实验结果表明:随着磨削速度和进给速度增大,磨粒的磨损和破碎现象加剧;随着去除材料体积的增加,微磨具直径先是急剧减小,而后呈线性减小趋势;加工表面的粗糙度随着去除工件体积的增加总体呈下降趋势.研究结果为提高微磨具的使用寿命和加工性能提供了理论参考和实验依据.     

对市场细分的新思考

在营销活动中，如何对市场进行有效的细分始终是值得我们重点研究的课题。文章针对企业市场细分过程中存在的两极分化的现象，提出了企业在细分市场时要配合运用市场泛化的策略，以达到有效细分市场的目的。     

New Voronoi Diagram Algorithm of Multiply-Connected Planar Areas in the Selective Laser Melting

This paper studies the practical generation of Voronoi diagrams for multiply-connected planar areas bounded by line segments. The core of the algorithm was calculating Voronoi polygon of every Voronoi object in planar areas independently. The main approach had two steps. The first step was calculating all relevant bisectors of every Voronoi object. The second was combining obtained bisectors into completed Voronoi polygons individually. All code was implemented in Visual C++ platform. The resulting code was extensively tested in real-world data and its practical running time grew only linearly. Three statistical CPU-consumption charts had been drawn with the Voronoi diagrams computation data, and compared with other published codes for computing Voronoi diagrams. The algorithm was applied to compute offsetting of slice area consisting of large-scale line segments for the selective laser melting (SLM) trajectory scanning technology which is a kind of rapid prototyping (RP). The experimental results of offsetting for slice area based on Voronoi diagrams show that the approach is effective and simple for polygon offsetting problems. The method is helpful to those offsetting work and can provide more effective offsetting solution.     

TiO2对粉煤灰及石英砂制备微晶玻璃组织转变的影响

利用粉煤灰与石英砂制备微晶玻璃，并对其进行不同工艺的热处理．通过对热处理后的试样研究发现：当粉煤灰质量分数为30％，未加TiO2时，试样在780℃加热时首先析出过渡相Ca2SiO。，在随后的高温晶化过程中，过渡相溶解消失，析出更稳定的平衡相钙长石；当TiO2质量分数为0—15％时，随着TiO2含量的增加，在780℃加热时由析出梭形的Ca2SiO。微晶转变为析出粒状的钙长石微晶；当粉煤灰质量分数增加到40％，TiO2质量分数为3．5％时试样中出现网状微晶组织，而加入的形核剂TiO2质量分数达到5％时试样中无网状微晶组织出现，说明TiO2对网状组织的析出具有明显抑制作用．     

Atomic packing and short-to-medium range order evolution of Zr-Pd metallic glass

A larger-scale Zr₇₀Pd₃₀ alloy system has been simulated using molecular dynamics (MD) to investigate structure evolution in Zr₇₀Pd₃₀ metallic glass. The simulated pair distribution function of Zr₇₀Pd₃₀ metallic glass agrees well with the experimental results. Voronoi polyhedron analysis indicates that the icosahedra are not randomly distributed in space, but form characteristic intercrossed icosahedral clusters with medium-range order. Intercrossed icosahedral clusters are the dominant local configurations in Zr₇₀Pd₃₀ metallic glass and probably cause the quasicrystalline phase discovered in Zr₇₀Pd₃₀ metallic glass.     

塑料门窗质量影响的因素分析

本文介绍了塑料门窗的加工制作安装过程中各种对门窗质量的影响因素,并进行了分析,结合实际工作经验指出了具体的要求和措施,从而保证了塑料门窗的质量.     

GFRP加固带壁柱砖墙抗剪面积的简化计算

通过1片未加固带壁柱砖墙和9片玻璃纤维增强复合材料(GFRP)加固带壁柱砖墙的抗震性能试验,分析带壁柱墙体中壁柱对墙体抗剪承载力的影响,并提出壁柱影响系数.从等效抗侧移刚度入手,推导出壁柱影响系数最大值的计算表达式;运用壁柱隔离法,推导出壁柱影响系数的最小值计算表达式,并结合壁柱的开洞损伤情况,给出壁柱影响系数的统一表达式,从而简化了计算.最后,通过试验验证该系数提出的合理性.     

玻璃组成对CaO-Al2O3-SiO2系玻璃烧结、晶化和性能的影响

采用烧结法制备以钙长石为主晶相的微晶玻璃.采用差热分析(DTA)、X射线衍射(XRD)、扫描电镜(SEM)和性能测试研究玻璃组成对玻璃的烧结、晶化特性和性能的影响.结果表明:随着CaO含量的增加,玻璃转变温度和析晶放热峰温度逐渐降低,而且析晶放热峰变得尖锐;增加氧化钙降低玻璃的析晶活化能,有利于玻璃的析晶;随着SiO2量的增加,玻璃转变温度和析晶放热峰温度移向高温,使玻璃的析晶困难;玻璃样品的烧结温度随CaO含量的增加而降低, 但过多的CaO促进硅酸钙的析出,增加样品的介电常数和热膨胀系数;增加SiO2能够降低微晶玻璃样品的热膨胀系数,改善其介电性能;所制备的微晶玻璃具有相对密度高(≥98.3%),介电常数适中(6.9～7.5),介电损耗低(≤0.1%),热膨胀系数低(3.8×10-6～4.5×10-6 /℃),烧结温度(900～1 000 ℃)低,及介电常数温度稳定性低(66×10-6～113×10-6 /℃).     

浙东南沿海地区中生代火山岩—侵入杂岩形成条件的实验模拟

本文研究了浙东南沿海地区中生代火山—侵入杂岩的熔融温度,老浆粘度及其与岩石成分之间的关系,讨论了它们的岩石学意义。