PVA固结磨具研磨硬磁盘基片的接触压强分布

目的为了获得铝质硬磁盘基片研磨过程中的接触压强分布对基片平面度的影响规律.方法建立了铝质硬磁盘基片使用PVA固结模料磨具研磨过程的接触力学模型和边界条件.利用有限元的方法对接触压强分布进行了计算和分析,并利用研磨实验对计算获得结果进行了验证.结果获得了研磨过程的磁盘基片与PVA磨具间的接触表面压强分布形态,以及PVA固结磨具的几何和物理参数对压强分布的影响规律,确定了接触压强分布形态是产生磁盘基片平面度误差的重要因素之一.结论接触压强的分布是不均匀,在基片的内径和外径邻域内接触压强增大,导致材料去除率增大,使被加工基片产生平面度误差.选择合理地PVA磨块弹性模量与较小的PVA磨块厚度,可以接触表面压强场分布趋向均匀,从而改善磁盘有效区域的平面度.     

晶体的超精密平面抛光

修正环型抛光机用于超精密平面抛光,并对沥青抛光进行了运动学分析。基于得到的方程式,发现在相同条件下,计算出的抛光量和平面度与60mm直径的玻璃圆板工件的实验值非常一致。提出了用于改善抛光平行度的偏心分布载荷技术。获得了1     

应用圆筒形行波压电振子的流体抛光实验研究

应用圆筒形行波压电振子设计了流体振动抛光装置。选取压电振子第十阶弯曲模态作为硅片抛光实验的工作模态,利用化学机械抛光浆料作为抛光液体,对不同表面形貌的硅片进行了抛光实验。实验结果表明硅片表面粗糙度得到改善。该方法也说明流体振动抛光更加适用于对已经具有较高表面平整度的抛光片进行二次抛光。     

光纤连接器端面抛光计算分析

利用ANSYS软件对光纤连接器抛光时端面接触压强分布进行计算分析,通过实验研究证明计算是正确的,从而为光纤连接器端面抛光的优化分析提供充分的理论依据.     

基于Excel的平面度误差最小二乘法评定

平面度是形状公差的主要项目之一,其误差的测量与评定在几何测量中有着重要的意义。根据最小二乘法原理建立理想平面的数学模型,对平面度误差进行评定分析,并举例说明了Excel在平面度误差数据处理方面的可行性。结果证明Excel在平面度误差最小二乘法评定过程中进行数据处理简单实用,有推广价值。     

用最小区域法求解平面度误差

针对学生在求解平面度误差时不易正确，迅速地求出最终结果的情况，提出一种平面度误差评定的最小区域快速算法。此算法思路清楚，无需对被测平面的类型进行判别，每一次旋转都能使两平行包容平面的距离减小，从而迅速地求出符合铁平面度误差值。     

求解零件平面度误差的投影变换法

简述了求解零件形状误差－平面度误差的几种方法,并提出了一种新方法,用画法几何学中的投影变换法来求解符合最小条件的平面度误差,并与解析法进行了比较。     

盘形超声压电振子的抛光实验研究

应用盘形超声压电振子在抛光实验装置上对硅片进行了化学机械抛光,比较了附加行波超声振动的化学机械抛光与传统化学机械抛光的实际效果,实验结果表明,在相同的实验工况下,施加行波超声振动相对于不施加振动,能明显改善硅片化学机械抛光的表面质量。振子振幅的增大对改善硅片表面质量有利。     

平面研磨中磨具与工件接触区压强的理论研究

平面研磨加工中磨具与工件接触区的压强分布对于磨具的均匀磨损，保证磨具和工件的面形准确度都是非常重要的。针对平面研磨加工中磨具上金刚石丸片的实际排列情况，采用力学分析方法对磨具与工件接触区的压强分布进行了模拟计算，给出了计算压强的一般公式，分析了工件半径和偏心矩对压强分布的影响。结果表明，在确定的加工系统中，当偏心距适当取值时，接触区压强呈均匀分布，对保证磨具的均匀磨损和工件的加工面形准确度提供了依据。     

多无限远目标模拟装置光轴共面测试技术研究

提出一种基于激光准直五棱镜回转扫描和CCD技术的非接触检测方法,通过检测三块立板平面度来实现对多无限远目标模拟装置光轴共面度的高精度非接触测量。给出误差评定方法,同时对仪器精度进行分析,通过实验测得共面度为0.039mm,满足精度要求。     

机械法研磨CVD金刚石厚膜

柱状生长的CVD金刚石膜生长面非常粗糙，并且粗糙度随着膜厚的增加而增加，限制了它的应用，必须对其抛光,本文采用了机械研磨法来研磨CVD金刚石厚膜，研磨速率达6．1μm／h，厚度去除了36．9μm，粗糙度Ra从5．9μm降至0．19μm．     

单晶碳化硅晶片高效超精密抛光工艺

为改善现有碳化硅抛光方法存在的效率低、有污染、损伤大等问题,提出采用机械研磨与光催化辅助化学机械抛光组合工艺抛光单晶碳化硅晶片.光催化辅助化学机械抛光利用纳米二氧化钛在紫外光照射下生成羟基自由基的强氧化作用原子级去除碳化硅.通过L9(33)正交试验研制光催化辅助化学机械抛光抛光液,采用对碳化硅晶片表面粗糙度跟踪检测的方法确定优化加工工艺.甲基紫有机显色剂静态氧化试验结果表明:光催化剂对抛光液氧化性的影响最大,其次是电子俘获剂,再次是分散剂;较好的抛光液配方为二氧化钛0.5 g獉L-1、过氧化氢1.5 mol獉L-1、六偏磷酸钠0.1 g獉L-1.确定的优化抛光工艺为:采用5μm和2μm金刚石微粉分别研磨单晶碳化硅晶片30 min,材料去除率分别为8.72μm/h和4.56μm/h;然后采用光催化辅助化学机械抛光单晶碳化硅去除机械研磨带来的损伤,粗抛光选用0.5μm氧化铝微粉抛光60 min,精抛光选用0.05μm氧化铝微粉抛光50 min,粗抛光和精抛光的材料去除率分别为1.81μm/h和1.03μm/h.用该工艺抛光单晶碳化硅,获得的表面粗糙度约为0.47 nm,基本能满足单晶碳化硅高效、超光滑、低损伤的抛光要求.     

用于ULSI铜布线的化学机械抛光分析

对ULSI中多层金属铜布线的CMP（化学机械抛光）进行了理论分析，介绍了Cu-CMP模型与机理及其去和学过程，抛光液的种类及其存在的问题，并对Cu-CMP的研究作了进一步探讨。     

新型热作模具钢4Cr5Mo3SiVNb的研究

在H11钢的基础上，通过分析碳化物类型对热作模具钢性能的影响，设计了一种新型热作模具钢4Cr5Mo3SiVNb，研究结果表明，新钢种具有微细的显微组织和较高的强韧性配合，并且回火稳定性及等向性也较好。     

Effects of bioleaching on the mechanical and chemical properties of waste rocks

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks,and play an important role in metal recovery and dump stability.This study focused on the characteristics of waste rocks subjected to bioleaching.A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process.Mechanical behaviors of the leached waste rocks,such as failure patterns,normal stress,shear strength,and cohesion were determined through mechanical tests.The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump.The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching.The dump porosity and rock size change under the effect of dissolution,precipitation,and clay transportation.The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.     

矿渣活性激发方式的研究进展

粒化高炉矿渣具有潜在的水硬性,作为水泥混合材和混凝土掺合料代替熟料和水泥,不仅节约资源和能源、减少CO2排放,还能改善混凝土的性能.主要论述了影响矿渣潜在水硬活性的因素,介绍了矿渣活性激发方式的研究进展并比较了各活性激发方式的优缺点,探讨了该领域的发展方向,即寻找更为有效的化学激活剂、提高机械激活效率、探索有效且成本较低的养护制度以及三种活性激发方式的复合运用.     

基于逐步回归法研究薄板钢化学成分与力学性能的关系

基于逐步回归分析法,从各种元素对Q235,Q345B,SS400等三种薄板钢力学性能的影响入手,研究了不同成分的薄板钢的化学成分与力学性能之间的定量关系.     

Effect of Post-spinning Modification on the PAN Precursors and Resulting Carbon Fibers

The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u＇ere characterized by the combiination use of densities, wide-angle X-ray diffraction （WAXD）, X-ray photoelectron speetroscopy （XPS）, elemental analysis （ EA ）, Fourier traasform infrared spectroscopy （FT-IR） and scanning electron microscope （SEM）, etc.KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor.fiber, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 % , but a decrease of 16. 52% in Young＇s modulus.     

Preparation and lab evaluation of a new denture adhesive

To develop a new kind of denture adhesive (DA), then to evaluate its mechanical and chemical properties, polyethylene oxide, methyl cellulose, sodium alginate, and cellulose ether, were viewed as four main factors, which would affect bonding load of DA, while two levels of each component were differentiated. Following table L12(211), twelve different formulae were designed by orthogonal design and bonding load values were recorded. According to bonding load of each formula, the optimized formula was selected out as this new adhesive material, Comfort-DA II. The changing of bonding load values of Comfort-DA II marinating in artificial saliva were measured, and an existing product, Protefix and Comfort-DA, were used as controls. Following initial load readings, samples and controls were measured from 1- to 12- hour intervals, respectively. Comfort-DA II was diluted at 1.0%, 2.0%, 3.3%, 5.0%, and 10.0% concentrations, and pH values were measured at 1-, 2-, 3-, 4-, 5-, 6-, and 8-hour intervals. Comfort-DA II presented as a pale-yellow paste. Group 6 gained the highest bonding load value of [193.8 (4.2)] N. The mean bonding load of Comfort-DA II was statistically different to Comfort-DA (p = 0.004) and Protefix (p = 0.006). Comfort-DA II exhibited a progressive increase in pH value over time and was slightly alkaline. Comfort-DA II showed significantly elevated mechanical and chemical properties, comparing to Comfort-DA. The results also indicate that orthogonal design may be an efficacious way to develop new dental materials.     

锰铁合金烟气灰潜在活性激发与评价

烟气灰是从锰铁高炉烟道中收集下来的废渣,含有CaO、MgO和Al2O3等活性化学成分,但玻璃体数量较少,活性较低。文中采用机械活化和化学激发并用的方法,提高烟气灰的活性,并按照GB/T 12957-2005规定的比强度法对烟气灰活性进行了评价。结果表明:机械研磨有利于烟气灰的活性激发,随着粉磨时间的增长,烟气灰的比表面积增大,粒径趋于向小粒径方向分布,机械研磨20~35 min,烟气灰活性系数可达0.8;化学激发剂可进一步提高烟气灰的活性,掺入5%的自配FAA复合激发剂可使烟气灰的活性系数提高至0.9以上。