非球面表面形状的线测量技术

描述了一种在超精密磨削机床上基于误差分离法的非球面表面形状精密测量系统.首先,论述了一般用于平面形状测量的两点法不能直接用于非球面形状测量的原因在于测头的设置误差会引起很大的形状测量误差.提出了先通过两点法测量平面形状得出机床的运动误差,然后对测量非球面形状的另外一个测头的输出进行补偿以得出正确的非球面形状.用此系统测量了一个直径为30 mm的非球面镜头的表面形状.     

超精密磨削大型光学非球面元件的研究

介绍了加工大型光学非球面的超精密数控磨削系统，给出了用来生成NC加工软件的加工非球面时砂轮的中心位置的求解模型，在此基础上讨论并给出了由砂轮安装产生的砂轮与工件主轴的偏心误差形成的加工工件面形误差的计算模型，并提出有效的工具路径补偿方法。通过计算机模拟验证了这种补偿方法的可靠性。     

非球面模具超精密补偿加工技术

为了实现非球面模具的超精密数控加工,研究了加工轨迹算法原理及整个软件系统的结构与实现.提出了基于表面粗糙度均匀化的工件进给速度控制法,分析了工具磨损误差和工件形状误差,重点提出了误差补偿方法,同时也讨论了采用砂轮平行磨削法时避免加工干涉的方法.软件能生成高精度的加工与补偿加工数控程序文件.最后,在一台镜面磨床上实验加工直径为6 mm的碳化钨透镜模具,经过多次补偿加工后,获得了谷峰值为0.123μm,误差均方根为0.021μm的表面形状精度.     

超精密车削金刚石刀具刃口误差的高精度补偿

超精密车削中的金刚石刀具刃口误差的补偿问题一直是制约高精度非球面车削直接成形的瓶颈技术,尤其对于大相对口径,深度非球面的车削,金刚石刀具刃口误差对最终的面形的影响非常大.传统补偿方法是根据轮廓仪的测量结果对刀具刃口误差进行修正,但是该方法存在测量时间长,高频误差大,加工效率低的缺点,本文最先提出利用车削表面面形误差拟合...     

数控机床热误差的建模与预补偿

研究了数控机床热误差的预补偿方法。建立了基于主轴转速的热误差自回归模型,从而不需要测量机床的温度场就可以预测热误差。在加工前通过修改工作的数控加工程度即可进行补偿,大大简化了误差补偿过程。可应用于中等精度的数控机床。     

叶片数控喷丸强化路径设计与实现

目的生成发动机叶片数控喷丸强化路径,以提高喷丸成形的精确性,生成机床数控代码。方法针对发动机叶片三维数模,采用截面法生成了喷丸强化的路径,根据叶片型面特点规划了喷丸参数,并分析了WBM数控喷丸机机构,建立了由喷头路径点和喷射方向反解设备控制代码的计算方法。结果提供了叶片数控喷丸强化机床前、后置处理方法,开发了相应的配套软件。结论在WBM型数控喷丸机上进行了叶片喷丸实例验证,可以将此方法应用于实际零件的生产,为提高叶片数控喷丸强化的精确性和效率提供了技术支撑。     

回转运动坐标定位精度的检测与误差补偿模型

在对回转运动坐标定位精度的干涉测量原理和方法进行深入研究的基础上，采用激光干涉法检测混联机床C轴的定位精度和重复定位精度，并做出了基于测量数据的混联机床C轴单向均位偏差特性曲线，推导出了C轴顺、逆时针旋转定位误差数学模型。利用最小二乘法拟合得到了机床回转运动坐标目标位置的均值误差补偿数学模型，提出了一种回转运动坐标定位精度的激光干涉测量方法和误差补偿模型的建模方法。     

数控机床定位精度的检测与误差分析

本文介绍了双频激光干涉仪的工作原理及齿条和丝杠传动车床的基本构成,利用激光干涉仪对车床定位精度的检测,分析车床的运动精度误差,根据分析结果对车床的传动部件做必要的调整,再对调整后的机床进行检测,根据定位误差得出相应数控系统的误差补偿数值,利用数控系统的补偿功能对机床定位进行补偿,以使机床的定位精度达到设计的标准值。     

基于部分补偿干涉的非球面顶点曲率半径加工误差测量

测量非球面顶点曲率半径加工误差对预估成像系统质量和计算机辅助装校有重要意义。传统的部分补偿干涉系统只能测量非球面面形误差,即被测非球面与标称非球面之间的不规则偏差。通过分析系统剩余波前特定像差项随被测面位置的变化关系,基于部分补偿干涉原理,提出了一种非球面顶点曲率半径加工误差测量方法,测得非球面顶点曲率半径加工误差。仿真实验结果表明,所提出的误差测量方法具有可行性,其原理相对测量精度不低于0.003%。     

混联复合机床主旋转轴精度的光电检测与补偿

为了达到对混联机床主旋转轴精度准确评价的目的，采用单频激光干涉仪进行精度检测，并为机床主旋转轴定位误差的补偿做准备。针对干涉仪的测量原理进行了深入研究，分析了激光干涉仪在机床主旋转轴测量中测量精度的主要影响因素和误差补偿，提出了一种简便、可靠的检测方法。最后通过实验验证了设计的检测方案，取得了综合测量结果。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.