Rheological Properties and MR Polishing Characteristics of Core Shell-Structured Silica-Coated CI Particles

Recently,ultra-precision polishing processes using smart materials such as magnetorheological(MR)fluids have been used for optics parts such as aspheric lenses.The MR fluid applied in MR polishing is a phase controllable suspension comprising a mixture of CI particles and non-magnetic fluids such as mineral oil and water.The fluids are a kind of smart material that can be controlled according to their flow properties such as viscosity and stiffness.Water-based MR fluids are easily oxidized if the fluids are exposed and this oxidation can bring irregular polishing results.Also,this phenomenon is one of several factors that reduce the life time of MR fluids.In a previous work,CI particles were coated with a polymer or a composite for the improvement of dispersion stability and prevention of corrosion due to oxidation.From this study,the rheological properties such as viscosity and sedimentation of coated CI particles with silica were investigated with a rotational rheometer;MR polishing characteristics of BK7 glass were studied in order to investigate the surface roughness.The wheel speed and magnetic field intensity were chosen as variables.     

Radiation Characteristics of Rectangular Patch Antennas with an Array of Pins

The patch antennas with an array of pins (pin array patch antennas) with excellent radiation characteristics are investigated for various substrate thicknesses.The radiation in the horizontal plane of a pin array patch antenna is very small campared to that of a conventional patch antenna.And the increase of forward radiation and the decrease of backward radiation of a pin array patch antenna are tained than these conventional one's.Also the half-power beamwidth of E-plane radiation pattern of a pin array patch antenna is narrower compared to that of the conventional so that the directivity is improved.     

面向H.264/SVC空域-质量域可伸缩编码的码率分配算法

 针对H.264/SVC空域-质量域可伸缩性,本文提出了一种基于模型的多层次码率优化分配算法.通过分析各编码层间的相关性,对空域和质量域视频层的码率和失真特性进行了建模.在此基础上,将H.264/SVC空域-质量域两维度码率分配问题描述为一个两阶段最优化问题进行求解.最后,代入提出的率失真模型,使用拉格朗日乘数法,求取该分配问题的最优数值解.大量实验结果可以看出新的率失真模型所提供的高效码率分配算法,大幅度提高了现有参考代码JSVM的性能.     

Characteristics of Micro Electrochemical Polishing to Improve the Surface Quality of the Stainless Steel Tube

Electrochemical polishing is the anodic dissolution process without contact with tools,is a surface treatment method to make a surface planarization using an electrochemical reaction with low applied current.The surface quality is mainly affected by the many process parameters.To improve the surface quality,the control of parameters is very important.The aim of this study is to investigate the characteristic of electrochemical polishing effect for inner diameter of Stainless Steel Tube.In order to analyze the characteristics of surface quality were measured in terms of temperature,applied current and machining time.The investigation can enhance the surface quality of inner diameter Stainless Steel Tube.Therefore,we have verified improved results by using selected optimal conditions.     

A superposition approach to the stress fields for various blunt V‐notches

This paper deals with the problems of blunt V‐notch with various notch shapes. The purpose is to develop a new method capable of obtaining more accurate solutions for the stress fields around a blunt V‐notch tip under opening and sliding modes. The key method is to use the principle of superposition for linear elastic materials. On the basis of the superposition method and the conventional stress fields for a sharp V‐notch, the stress fields useful for any shapes of blunt V‐notch is proposed. The notch stress intensity factors are estimated by the numerical analysis with finite element analysis, and then the effectiveness and validation of the proposed superposition approach are discussed by comparison with the results from the literature.     

Transverse Flux Induction Coil for Uniform Bar Heating Excluding Edge

This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of 50~150mm from the both edges,so Transverse Flux Induction Coil(TFIC)including a magnetic core is proposed and optimized to supplement this fault.The solutions on the electromagnetic field are obtained numerically by commercial code MAXWELL 3D software from ANSYS Corp.and then,verified experimentally by pilot-scale tests,in which the TFIH was manufactured with a nominal power of 100 kW at a fundamental frequency of 1 kHz.Ultimately,TFIC having geometrically the optimized magnetic core made the heating pattern U-shaped,so could supply a desirable temperature profile for the rolling process.     

Influence of Endogenous Proteases and Transglutaminase on Thermal Gelation of Salted Squid Muscle Paste

ABSTRACT: Thermal gelation of salted squid mantle muscle paste was studied in relation to endogenous proteases and transglutaminase. Myosin in the paste was preferentially degraded into 130-kDa and 90-kDa fragments at an optimum temperature of 30 °C. Degradation was inhibited with EDTA or 1,10 phenanthroline, suggesting the presence of metalloproteases. Myosin degradation was markedly reduced above 40 °C. Although 10 mM Ca²⁺ increased cross-linking of myosin heavy chains by activating the endogenous transglutaminase, setting effect on thermal gelation of the paste was offset by degradation induced by simultaneously activated calpains. Ca2+ and the alpain inhibitor, E64, significantly improved the breaking strength and strain of thermal gels preincubated at 40 °C.     

Mode I and mixed mode fracture of polysilicon for MEMS

An experimental study was carried out to investigate the local and effective fracture behaviour of polycrystalline silicon for microelectromechanical systems (MEMS). The apparent mode I critical stress intensity factor was determined from MEMS‐scale tension specimens containing atomically sharp edge pre‐cracks, while local deformation fields were recorded near the crack tip, with high resolution by the in situ Atomic Force Microscopy (AFM)/Digital Image Correlation (DIC) method previously developed by this group. The effective mode I critical stress intensity factor varied in the range 0.843–1.225 MPa√m. This distribution of values was attributed to local (in grain) cleavage anisotropy and to enhanced grain boundary toughening. The same sources resulted in very different local and macroscopic (apparent) stress intensity factors, which, combined with the small grain size of polysilicon (0.3 μm,) were the reason for subcritical crack growth that was evidenced experimentally by AFM topographic and AFM/DIC displacement measurements. The effect of local in‐grain anisotropy and granular inhomogeneity was stronger under mixed mode loading of edge cracks inclined at angles up to 55° with respect to the applied far‐field load. The K_I–K_II locus was characterized by scatter in the K_Ic values but on average it followed the curves calculated by the maximum tensile stress and the maximum energy release rate criteria calculated assuming isotropy.     

Alumina–mullite–zirconia composites: Part II Microstructural development and toughening

Densification characteristics and fracture toughness of the alumina–mullite–zirconia (AMZ) composites fabricated by the colloidal mixing route were examined. The densification of boehmite–silica–zirconia precursor compacts was characterized by three distinct stages. Stage I was represented by a rapid shrinkage between 1100 and 1300°C and was caused by the viscous flow sintering of the SiO2 component. Stage II was characterized by a temporary cessation of the shrinkage caused by the mullitization. Stage III was represented by a restoration of the shrinkage for temperatures above 1450 °C. The α-Al2O3 seeding facilitated the formation of elongated grains in the AMZ composites, and these elongated grains correspond to α-Al2O3. The toughening caused by the microcrack nucleation was comparable to that by the t → m martensitic transformation and increased with increasing total content of zirconia.