本文研究了一水铝石矿机械活化球磨溶出的最佳工艺条件:装球量30％;钢弹转速80r/min;球磨钢球的大小采用混合球;给矿粒度为-1mm.研究了一水铝石矿在不同温度下、不同溶出时间的溶出性能,并作出了相应的动力学分析,表明:一水硬铝石在210 ～ 245℃均是化学反应控制,球磨溶出降低了反应的活化能,使该铝土矿溶出活化能由82.03kJ/mol降低到69.32kJ/mol.

In this paper, a new type of grinding wheel and its manufacturing production process are introduced. The new BCB (Bamboo Charcoal Bond) grinding wheel was made of bamboo charcoal, phenolic resin and abrasive powder with higher press and temperature. To investigate its mechanical features, such as Rockwell hardness, resistance to abrasion, and resistance to pressure, some experiments on three BCB samples with different Resin weight ratios 20%, 25%, 30%, were carried out. The results showed that the BCB sample with proper moulding process and Resin weight ratio had better performance.

武钢鄂州球团厂高压辊磨机系德国进口设备,作为主要备件的辊子也需进口,不仅价格高、订货周期长,且需全额预付订金,条件苛刻.为摆脱进口备件制约,降低球团生产成本,该厂组织开展了高压辊磨机辊子国产化修复攻关,并取得成功,成效显著.

Voids in plated through-holes are caused by many different processing problems.This paper will show how to identify rim voids by PCB production process parameter with micro section observation.The results indicate that stronger correlation existed in core board between the proportion of rubber polymer to filler and type of PP,which could influence the quality of lamination and drill.The primary reason of VPTH formed was by process parameter,the condition of assisting machine and processing time for electroless and electroplate process.The reason of defect was found for every abnormal board.Effective improvement measures not only had a definite object in view of prevention measures,but also improved quality and percent of certified products,this measure had the vital significance to improve reliability of printed circuit board.

By improving on the Quad-tree LOD algorithm, this paper proposes a new algorithm based on the terrain partitioning and simplifying the terrain by using grid models of different levels of detail dynamically.This algorithm can be reduced the number of triangular facets in the terrain scene.The experimental results show that this algorithm can generate continuous multi-resolution terrain model and improve the efficiency of real-time rendering.

BCB(Bamboo Charcoal Bonded) grinding wheel is a new kind of grinding wheel developed by bamboo charcoal-phenolic resin composite for ELID(Electrolysis In-process Dressing) grinding technique. To study the affection of the ground workpiece surface roughness and removal rate with this new kind of grinding technique, the stainless steel SUS304 was ground using BCB grinding wheel in different machining parameters with ELID grinding condition, and the machining characteristics of BCB grinding wheel has been researched. The experimental results indicated that the ground workpiece surface roughness can be reached to Ra 0.010μm, and the efficient and precision machining with BCB grinding wheel by ELID grinding technique has been achieved for hard-to-cut materials. Finally, by studying of the grinding wheel surface condition and wear, the BCB grinding wheel grinding mechanism has been preliminary discussed.

The permeated grinding wheel was a new kind of grinding wheel, which was permeated by the chemical additives and solid lubricant into the interior gaps of the grinding wheel. Therefore, the grinding wheel can form a lubrication film on the surface of the grinding wheel. This grinding wheel has some good features, such as lower grinding temperature, smaller grinding force, higher life of the grinding wheel, and can prevent the adhesion of chip onto the grinding wheel surface. The experimental results indicate that the ground surface quality and grinding efficiency have been remarkably improved for more hard-to-cut materials.

In this paper, the mechanism of Electrolysis In-process Dressing (ELID) lapping process using new BCB (bamboo charcoal bonded) abrasive wheel is researched. Some experiments of machining for silicon wafers were carried out for exploring the effect of some machining process parameters on material removal rate and surface roughness. Experiments show that: Material removal rate and machined workpiece surface roughness are increased with increase of the lapping wheel’s rotation speed and processing loading; The machined workpiece surface quality is affected with the lapping wheel surface condition, due to the abrasives are trued by electrolysis dressing in the lapping process, therefore the BCB lapping wheel always keeps better machining condition to obtain excellent machined workpiece surface quality efficiently.

Electronic in-process dressing (ELID) grinding will be a main technology of ultra-precision grinding which has been widely adopted to the ultra-precision and high effectively machining of hard and brittle materials. This study puts forward a new environmental friendly bamboo charcoal bonded (BCB) grinding wheel and develops a new ELID grinding fluid. An oxide layer is mostly determined by the electric performance of grinding fluid in the experiment. This paper founds a model to forecast grinding fluid’s electric performance by BP neural network and MATLAB. This method can be used in developing of ELID grinding machining fluid to improve the ELID grinding effect.

This paper introduced a polishing process for planarization of gallium nitride (GaN) wafer by polishing slurry that is made up by the chemical reaction with H2O2 solution and iron. Some different polishing parameters in the polishing process has been analyzed, which affect the surface quality of wafers, such as slurry particle size, polishing times, polishing slurry etc., and trying to improve the polishing process by optimization of the polishing parameters. The experimental result showed that this polishing method has an effect on the surface quality of GaN wafers, finally, the efficient and precision machining with surface roughness of GaN wafers of Ra0.81 nm has been gained by the CMP polishing process.

How to achieve the precision double-sided polishing process is a important issue for wafer manufacturing, it depends on machining condition such as machining environment, polishing speed, polishing operation mode, polishing pressure, polishing fluid etc. The key factor to the wafer surface quality is the stability of the polishing pressure. This paper analyzes the impact of double-sided polishing pressure in polishing process, using AMESim software to simulate the pressure standard deviation's changes under diffrent polishing pressures, and carries out some experiments to identify the impact of polishing parameters (such as the ring gear ratio, polishing speed, polishing pressure) to the polishing pressure stability and the wafer surface quality.

简述了水基金属切削液发展过程中现存的环境健康问题,并就环保型添加剂的开发及切削液中成分的变化具体介绍了水基金属切削液的研究进展情况,同时讨论了水基金属切削液的发展趋势.

A new BCB (Bamboo Charcoal Bonded) grinding wheel was developed by bamboo charcoal-phenolic resin composite under vacuum for ELID grinding technology. The pyrolysis behavior of the new bamboo charcoal-phenolic resin material was studied by thermo gravimetric analysis (TGA), and structural characterization of the new material was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), the friction characteristics was also investigated in this paper.

Dual-rotating plates lapping method is a new type of ball machining technology, in which the spin axis angle of the ball could wiggle up to 180°. An investigation was made to verify the motion model of the dual-rotating plates lapping. The ball motion parameters, such as revolution speed, spin speed and spin axis angle were detected experimentally. The results show that the calculated values and the measured ones of the ball motion parameters are almost identical. The motion model of the dual-rotating plates lapping method is thus verified valid.

This paper estimates agglomeration effects on labor productivity for more than 200 Chinese cities from 2001 to 2005, taking into account endogeneity of spatial distribution of employment and spatial fixed effects. Econometric results suggest that agglomeration effects in China are larger than US and European countries, and these effects became larger 2001 through 2005. Results also demonstrate agglomeration effects vary greatly among different parts of China. As control variables, human capital effects and regional fixed effects are estimated as well.

In this paper, a precise profile ELID grinding with Electrical Discharge Truing(EDT) has been introduced, and some experiments for efficient and precision EDT process with cast iron-bonded diamond wheel have been carried out with four types of medium: mist, water, pressure air, air, furthermore some machining parameters e.g. electric current, electric voltage have been discussed in detail. For analyzing of the accuracy of EDT process with cast-iron bonded diamond wheel, a profile measurement method with software of MATLAB was used for analyzing of the profiles of cast-iron-bonded diamond wheel and electrode. It can be found that the electrode’s profile can be kept with the consistent designed profile, and the grinding wheel with the designed profile has been got by the appropriate EDT process. Therefore the higher efficiency and precision EDT process can be achieved by the appropriate EDT machining parameters.

Double-sided polishing machine is widely used to high precision dimension, high accuracy surface, and ultra-smooth surface without damage layer for some hard and brittle workpiece such as silicon wafer, sapphire, ceramic, magnetic substrates, electronic materials, etc. Pneumatic loading system is the very crucial part of the double-sided polishing machine. The polishing machine's performances are directly determined by the loading precision. This paper establishes the modeling and simulation of pneumatic load system by AMESim and then gives optimization parameters to improve system performance, and the cure of load capacity is given.

The cemented carbide has high hardness,high strength,high wear and corrosion resistance.So it is very difficult to meet the demand of precision and super-precision machining by conventional grinding.In this paper,the cast-iron bonded diamond wheels with different grain size are adopted in ELID(Electrolytic In-Process Dressing) grinding cemented carbide.Experiment results show that,under the same feeding,the wheels with bigger grain size have higher grinding efficiency,which could make the dimension accuracy of the workpiece controllable.On the contrary,the wheels with smaller grain size could get better ground surface quality,but they have lower grinding efficiency.The ELID grinding states are decided by the ratio of the grain size and the thickness of the oxide layer on the grinding wheel.The oxide layer plays an important role in grinding process.Its formation is affected by the electrolysis parameters,therefore,high precision and efficiency ELID grinding could be achieved with the proper electrolysis parameters.

This study compares the effectiveness of different polishing slurries for Double Sided Polishing process of Silicon wafer in the polished surface roughness and stock removal rate, discusses the mechanism of Double Sided Polishing for silicon wafer with different type slurries, also the influence of the pH value, temperature and concentration of the slurries are discussed in this paper. Furthermore, by the optimization of the process parameters, the ultra-smooth of polished surface of silicon wafer has been got with higher efficient.

A friction force microscope (FFM) with different probes and a ball-on-disk (BOD) tribo-meter were used to investigate the tribological properties of diamond-like carbon (DLC) films. DLC films were prepared by chemical vapor deposition (CVD) method by altering the deposition parameters, and their morphologies and structural information were examined with an atomic force microscope (AFM) and the Raman spectrum. The wear traces of the DLC films after frictional tests were analyzed by an optical microscope. It is found that surface roughness and adhesion play important roles in characterizing the tribological properties of DLC films using FFM. Moreover, the debris accumulation is another significant factor affecting the frictional behavior of DLC films, especially for the sharp tip. The difference in coefficients of friction (COFs) obtained by the BOD method among different DLC films under water lubrication is much smaller than the case without water lubrication. The variation trends in COF for the flat tip and the BOD test are similar in comparison with the result obtained with the sharp tip. The wear traces after frictional tests suggest that DLC films under water lubrication are prone to be damaged more readily.