高水位地基处理实例

介绍高水位(距槽底300)条件下,地基处理的方法、检测及效果验证。为在此条件下进行施工作业提供依据。     

Removal of iron from milk of lime to produce pure precipitated calcium carbonate

ABSTRACT

Milk of lime (MOL) suspension is widely utilized in many industries; however, in some of the applications, such as the production of precipitated calcium carbonate (PCC), the suspension must be of high purity and quality. In other words, the amounts of iron and magnesium should be so little so that the final PCC product would be of high quality. The effects of initial temperature, quicklime particle size, amount of initial solid present, agitation rate, and time on the recovery of hydrated lime and iron/magnesium reduction efficiency were investigated through a central composite design (CCD) of experiments. The iron reduction efficiency and the weight recovery of hydrated lime were obtained as 91% and 98.5%, respectively. The reduction of magnesium was not significant in this stage. Moreover, approximately the whole existing SiO₂ was eliminated.     

钎焊金刚石砂轮磨削石材中金刚石粒度对磨削力的影响研究

本文通过测量不同金刚石粒度的高频感应钎焊金刚石砂轮磨削花岗石过程中的磨削力，对砂轮所受的法向力和切向力进行了研究。对不同粒度条件下磨削深度、进给速度和砂轮线速度对磨削力的影响进行了分析。研究发现磨削力随砂轮线速度的增大而减小，随磨削深度和进给速度的增大而增大，磨削深度对磨削力的影响程度比进给速度大。小粒度金刚石磨削时，磨削三要素对磨削力的影响比大粒度金刚石磨削时大。     

呋喃树脂自硬砂在纺织机械铸铁件上的应用

介绍呋喃树脂自硬砂在纺织机械类铸铁件生产中的实际应用，详细阐述了原材料选取，呋喃树脂自硬砂制备工艺、造型与制芯等工序的操作要点及应用实例，分析了呋喃树脂自硬砂代替普通粘土干型砂工艺的利益所在。     

Effects of blasting parameters on removability of residual grit

This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 μm. The velocity and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual grit weight was 7 to 17 g/m². The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased with the increase of the momentum of the grit particle. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

金属结合剂#600金刚石砂轮的接触放电修锐实验研究

针对微细金刚石磨粒很难从金属结合剂砂轮的胎体中出刃的问题，开发出一种新修锐方法一接触放电修锐、它采用一种旋转复合电极修整轮与砂轮接触磨削，在金属结合剂胎体与电极间产生微小的脉冲放电，逐渐去除砂轮的金属结合剂，使微细金刚石在砂轮工作表面出刃，达到精密修锐的目的。通过对金属结合剂#600金刚石砂轮进行修锐实验，研究其有效性、修锐条件和实际应用。实验表明，该修锐方法不仅不损伤微细金刚石磨粒出刃刃角，而且还可以消除磨粒周围的结合剂尾状物，产生较好的容屑空间。磨削光学玻璃(BK10)的试验结果显示它比机械修锐能够更好地提高磨削表面质量，Ra达到0．12μm。     

先进的模具加工设备与技术简介

介绍某厂近期引进的三套先进的模具加工、检测装备与技术：模具喷砂清理机，模具三维检测仪,模具加工中心.     

LDLT分解协处理器的并行结构研究

为提高LDLT分解协处理器的性能,基于FPGA平台,研究其并行结构。分析循环片间的数据依赖关系,提出LDLT分解细粒度并行算法,并在可扩展一维阵列处理器中加以实现,利用主机、算法加速器组成单精度浮点LDLT分解协处理器的并行结构。实验结果表明,与运行在2.50 GHz Pentium微处理器上的C代码相比,该协处理器可获得32.03倍~43.25倍的性能提升。     

单颗金刚石磨粒锯切运动学分析

引进运动学中的点的速度合成定理求解单颗金刚石磨粒锯切面积和锯切厚度，通过详细的理论推导推出了单颗金刚石磨粒锯切速度方程，锯切运动方程和锯切面积和锯切厚度的计算公式，结果表明，单颗金刚石磨粒锯切面积与前一颗金刚石磨粒所夹的圆心角成正比，与进给速度成正比，与锯切深度成正比，与金刚石圆锯片的转速成反比，且依余弦规律减小。     

Elastic stress field model and micro-crack evolution for isotropic brittle materials during single grit scratching

An analytical model for the elastic stress field in isotropic hard and brittle materials during scratching is presented. The model considers the entire elastic stress field and the effect of material densification that was ignored in past studies, and is developed under a cylindrical coordinate system to make the modeling process simpler. Based on the model's predictions, the location and sequence of crack nucleation are estimated and the associated mechanisms are discussed. A single grit scratching experiment with an increasing scratch depth up to 2 µm is conducted for two types of optical glasses representing isotropic brittle materials: fused silica and BK7 glasses. It is found that the model's predictions correlate well with experimental data. Median cracks are found to be formed first during scratching, and the corresponding depth of the scratch sets the basis for determining the critical depth for brittle to ductile machining. Lateral cracks are initiated in the plastic yielding region and deflect to the work surface to cause material removal, while Hertzian cracks interact with lateral cracks to help remove lateral-cracked material. Furthermore, it is found that, owing to its open network molecular structure, fused silica has a much worse ductile machinability than the BK7 glass.