bluuebunny/crossref_metadata_2025 huggingface dataset:
A Rapid Process for Fabricating Microfluidic Devices with a Low-Cost UV Curable Resin
Authors: Kuo Shu Ming , Yang Chao Chi , Hsieh Jien Tai , Lin Che Hsin
Published: February 2011

This paper presents a novel bonding-free process for fabricating integrated microfluidic devices with embedded electrodes utilizing low-cost UV curable resins. Commercial available UV glue is sandwiched between two substrates and is used for both the structure material and bonding adhesive. The pattern of micro-fluidic channels is defined using a standard lithography process while two substrates are bonded simultaneously during the exposure procedure. Once the pattern is defined, the un-cured UV glue was removed by vacuum suction to form the sealed microfluidic channel. With this simple approach, conventional bonding processes can be excluded for fabricating sealed microfluidic structures such that the developed method is essential for fabricating microchip devices with embedded electrodes. The thickness of the formed structures can be up to millimeter range and the smallest channel width is around 80 um (aspect ratio = 2). The overall process to fabricate sealed microchip device is less than 10 min since no time-consuming etching and bonding process in the developed process. An innovative micro-reactor integrated with in-channel micro-plasma generator for real-time chemical reaction analysis is fabricated using the developed process. On-line mass-spectrum (MS) detection of an esterfication reaction is successfully demonstrated, resulting a fast, label-free, preparation-free analysis of chemical samples. The developed process has shown its potentials for rapid and low-cost microdevice manufacturing.
Automatic Hyperbaric Welding of Sub-Sea Pipelines Repair
Authors: Zhou Can Feng , Jiao Xiang Dong , Xue Long , Chen Jia Qing , Fang Xiao Ming
Published: February 2011

Air diving are widely used in many shallow water areas, if applicable welding technology adaptive to such a condition developed, then operation cost of offshore structure repairs can be largely saved. In order to meet such a special requirement, an automatic GTAW welding process under high air pressures was researched. Firstly, the hyperbaric welding test chamber was designed and constructed in laboratory, and the welding machine was manufactured. Secondly, experiments under 1-7 bar air pressures were studied including linear welds and pipe butt welds, and high weld quality was obtained. Lastly, the hyperbaric welding sea-trial was carried out, and perfect 5G girth weld of sub-sea pipelines was produced.
Effects of Rare Earth Elements Erbium and Cerium on the Properties of Hardfacing Alloy
Authors: Zhang Di , Luo Zhen , Yuan Tao , Wang Rui
Published: February 2011

By the way of adding rare earth element into the coating of electrode, this article has studied the effects of rare earth element erbium and cerium on the properties of welding surface. Experiment results show that adding rare earth element to the welding rod coating could make the grains fine, increase the content of acicular ferrite and improve the hardness and abrasion resistances of weld metal. After joining 0.3% Er and 0.3% Ce, the weld metal's macroscopic hardness achieves 39HRC, enhanced 23.8%. And the relative wear resistance enhanced 25.6%
Improving Low-Ag Pb-Free Solder Performance by Adding Bi, Ni Elements
Authors: Sun Feng Lian , Liu Yang , Liu Yang , Wang Jia Bing , Zhang Hong Wu
Published: February 2011

In this study, some Ni, Bi elements were added into low-Ag (less than 1%) Sn-Ag-Cu (SAC) solder. The effect of these additive elements on the solderability, intermetallic compounds (IMCs), and electromigration performance of low-Ag SAC (LASAC) solder were investigated. With the increase of Bi content in LASAC-0.05Ni-xBi (x=0, 2.0, 2.5, 3.0, 3.5, 4.0) solders, the peak melting point decreases while the wetting area of solder alloy increases. With the addition of Ni, the IMC between Cu pad and LASAC solder transforms from Cu6Sn5 to (Cu1-xNix)6Sn5 and the morphology of the IMC turns from bulk-like to needle-like. Either the addition of Bi or Ni will slow down the IMCs growth rate during high temperature storage aging (HTS) at 180°C and has a positive effect on electromigration performance of LASAC soldering.
Study on a Cu-Fe Weld Metal of Manual SHS Welding
Authors: Xin Wen Tong , Li Zhi Zun , Wu Yong Sheng , Qu Li Feng
Published: February 2011

The paper presents a Fe-base manual SHS Welding material with CuO+Al and Fe2O3+Al being the thermit and adding ferroalloy materials for solving the problem of low mechanical properties of the manual SHS Welding joint. The structure and properties of the welded joint were studied. The results indicated that: the welding was fusion welding, and weld appearance is good. Cu-Fe alloy in the molten pool experiences liquid phase separation during rapid solidification, and the weld metal is macroscopically separated into one Fe-rich part and one Cu-rich part. Fe-rich phase is filled in the welding line. At the same time, tensile strength of the welded joint was close to 500 MPa, and impact toughness was close to 40J/cm2, and surface hardness was also close to HB350. It also indicated this technology can meet the need of repair of metal parts in field.
pH’s Effection to Electroplating Ni-SiC Plating on Aluminum Alloy
Authors: Chen Yan Fang , Chen Chun Mei , Meng Long , Jie Ya Fei , Sheng Jun Hao
Published: February 2011

This study is of aluminum alloy electroplating process pH alloy electroplating Ni-SiC properties. Research shows that the results show that, when the bath pH for 4.0, plating coating uniform structure, compact, the best performance, coating and maximum SiC content.
An Experimental Investigation on Railway Adhesion Properties under Water Medium and Dry Condition Respectively
Authors: Shen Peng , Wang Cai Yun , Wen Zhong , Liu Qi Yue
Published: February 2011

The effect of wheel speed, axle load and track curve radius on wheel/rail adhesion properties under dry and water medium condition was investigated in this paper using JD-1 wheel/rail simulation facilities with Hertz simulation method, and then testing method of “four horizontals and three factors” was adopted to analyze the influence degree of speed, axle load and track curve radius on wheel/rail adhesion. Results from the experiment are that: The adhesion coefficient reached maximum at creep ratio of 1.5% under dry condition, and 1% under wet condition respectively; the adhesion coefficient under water medium condition occupy about a proportion of 32%-50% of that under dry condition. adhesion coefficient would reduce with speed increasing, axle load increasing and track curve radius decreasing under dry condition, and reduce with speed increasing, axle load decreasing and track curve radius decreasing under water medium condition; As far as influence degree of three testing factors which have effect on adhesion coefficient is concerned, axle load is the first one, then speed, finally track curve radius under dry condition, and speed is the first one, then axle load, finally track curve radius under water medium condition.
Nonuniformity of Mechanical Property in the Weld Zone of Friction Stir Welded 7050 Aluminum Alloy Joint
Authors: Tian Yu Wen , Xu Fei , Li Wen Ya , Tang Zhong Bin
Published: February 2011

The distribution of mechanical property in the weld zone of friction stir welded 7050 aluminum alloy joint along the plane perpendicular to the welding direction was experimentally investigated by the non-contact measurement method. The results show that the elastic modulus presents a W-shape distribution across the weld zone. The elastic modulus in the weld nugget zone is increased due to the grain refinement. In addition, the elastic modulus in the advancing side is slightly less than that in the retreating side possibly because of the relatively higher temperature in the advancing side during the welding process. The strength in the vicinity of weld center is decreased while the ductility is enhanced. The tensile strength and yield strength in the weld nugget zone and thermo-mechanically affected zone are significantly decreased while the elongation is increased due to the change of strengthening mechanism. In the heat affected zone the strength is decreased compared to the base material because the second phase grows up.
Experimental Study on the Effects of Rotational Speed and Attack Angle on High Density Polyethylene (HDPE) Friction Stir Welded Butt Joints
Authors: Saeedy Sina , Givi M.K. Besharati
Published: February 2011

Friction stir welding (FSW) is a novel solid-state welding process and has been employed in several industries such as aerospace and automotive. Several parameters such as rotational speed, welding speed, axial force and attack angle play critical roles in FSW process in order to analyze the weld quality. The aim of this study is to investigate the effects of different rotational speeds and attack angles on the weld quality of high density polyethylene (HDPE). In the optimum welding condition, 75% of the base material strength is achieved. SEM micrographs show the changes of the weld microstructure which result in the reduction of the strength and the percent of elongation.
Preparation of Grafting Starch by HRP Catalyst and it’s Application in Leather Tanning Process
Authors: Lv Sheng Hua , Duan Jian Ping , Hou Ming Ming , Yan Xiao Liang , Liu Gang , Gao Rui Jun
Published: February 2011

Two grafting starch was obtained by grafting copolymerization of two synthetical vinyl monomers using HRP/H2O2 as catalyst. The structure of vinyl monomers was verified by 1H-NMR.The grafting polymer was proof by structures were verified by FTIR. The effect of mass ratio of starch and vinyl monomer on the grafting efficiency (GE) and grafting percentage (GP) was studied. The highest GE and GP of the first grafting starch was 35% and 32%, 59% and 50% for the second grafting starch when the vinyl monomer ratio was 9%. The molecular mass tested by GPC for the two kinds grafting starch with highest GE and GP were 54 600 and 63 970. The two mostly grafted starches were used as retanning agent. The increase ratios in thickness were 18.1% and 18.6% respectively and the tanned leather has excellent softness and flexibility.
The Mechanical Properties of Al-30Si Alloy by Friction Stir Processing
Authors: Jiang Ye Hua , Lu De Hong , Zhou Ming , Wei Shao Sheng , Zhou Rong
Published: February 2011

Friction stir processing (FSP) was applied to modify the surface of a hypereutectic alloy Al-30wt.%Si, the influence of FSP passes on the size and morphology of Si particles, the mechanical properties of the materials in the stir zone was investigated. In the nugget by FSP, the silicon particles were intensely refined to several micrometers and spheroidized, and the refinement and spheroidization degree increased with FSP passes. The tensile behavior of the alloy by FSP has typically plastic feature. With FSP passes increasing, the tensile strength and the elongation increased gradually, and the improvement ratio of the elongation is more obvious. The improvement is attributed to the spheroidization and refinement of silicon particles by FSP.
Investigation of Microstructure and Mechanical Properties of Pulsating Laser Cladding Coating
Authors: Peng Ru Shu , Tang De Weng , Fan Xiang Fang
Published: February 2011

The surfaces of 45 steel and 1Cr18Ni9Ti are coated with WFCL-11 by l pulsating laser cladding. Microstructure and hardness between substrate interfaces and surfaces of laser cladding coating are investigated. And the variation of their microstructure, mechanical properties and hardness of coating surface are analyzed under shock loading. The results show that the different material ingredients between substrate and laser clad effect their interfaces.
Influence of Recoating Parameters on Thickness of Resin Layer in High-Resolution Stereolithography System
Authors: Xu Guang Shen , Luo Sheng , Tan Dong Cai
Published: February 2011

Performance of recoating system is a key factor influencing building accuracy and fabricating resolution of stereolithography (SL) system. In order to obtain thinner resin layer, a piston recoating system was adopted in high-resolution SL system. To improve the recoating performance of piston recoating system, studies were carried out to investigate the influences of recoating parameters on thickness of recoating layer, and a mathematic model of resin layer thickness has been established. Experiments results show that thickness of resin layer increases with the gap between blade and object, and thickness of resin layer increases with the resin volume added into the vat during recoating. Experiments results also indicate that thickness of resin layer decreases with blade speed and blade thickness. The research provides a basis for optimizing the recoating parameters for the piston recoating system.
Laser Cutting Layout Based on Particle Swarm Optimization and Graphic Interference Detecting
Authors: Lin Zhi Wei , He Yong , Fu Jian Zhong
Published: February 2011

Laser cutting of thin metal parts involves packing 2-D arbitrary objects into rectangle work space. The problem is shown to be NP-complete. This paper presents a novel approach to solve the problem, by dividing the problem into 2 parts. The first part finishes packing minimum envelop rectangles of the objects by applying Particle Swarm Optimization (PSO) with the lowest line packing as its fitness function. The second part moves the objects to a most suitable place by detecting interference with neighbor objects. A complete interference detection method between two polygons, either convex or concave has been suggested. In addition, two approaches, both the scanning approach and the circumcirlcle approach, have been developed to find the neighbor objects of the current moving object. And the order to move the objects has also been found in a scanning manner. Computational experiments have been carried out both for the first and the second part and the results are inspiring.
Microstructure and Corrosion Resistance of 40Cr Steel by Laser Melting
Authors: Qiu Xing Wu
Published: February 2011

Laser melting was carryed out by HL-1500 CO2lase rmachine on 40 Cr steel. The phase composition, microstructure, microhardness and corrosion resistance of the melting coating were investigated by means of scanning electron microscope, X-ray diffractometer, electrochemical test system, salt spray tester etc. The result showed that, melt zone、transformation hardened zone and the heat affected zone as mainly region in melting coating. Laser melting coating constitute by Fe3O4, Fe3C and martensite etc. The microstructure are mixed martensite and undissolved carbides, acicular martensite and retained austenite. The microhardness increased nearly twice as that of the 40Cr when scanning speed is 2.0 m/min. With the increase of the scanning speed, the corrosion resistance increased first and then decreased.
Dry Sliding Friction and Wear Behavior of WC/WC-Ni Particles Laser Cladding Reinforced by Nano TiC on Mold Steel Surface
Authors: Yang Qiu He , Guo Shao Yi , Wang Li Xia , Li Xing Jun
Published: February 2011

To reduced the defect of the layer cladding reinforced by WC/WC-Ni Particles, and to attained the effective handicraft to strengthen the properties of the mold surface, using laser cladding technique , nano TiC reinforced WC/WC-Ni composite cladding were fabricated on the surface of H13 steel substrates. The cladding microhardness was measured with Victoria-hardness tester, the cross-section microstructure of the claddings was observed with optical microscope. The fabrication of the composite claddings was investigated. The friction and properties were examined under dry sliding conditions with a WTM—1E type ball-on-disc tester. The wear tracks were observed with a JSM-5610 type scanning microscope. The wear mechanisms were discussed as well. The results showed that, owing to the NanoTiC fine-crystalline strengthening and dispersive strengthening, the Nano TiC/WC/WC–Ni composite cladding was very compact and good blinding with the substrate after laser remelting, and then sub-micro-fracture and adhesion wear of WC cladding were reduced. During the friction process, Nano TiC particles had a significant influence on the Friction and wear behavior of laser cladding: The friction coefficient reduced and wear-resistance strengthened of composites with increasing proportion of TiC. The wear mass loss of the 20% TiC composite cladding reduced to about 1/3 of those with 5% TiC cladding.
The Research on Coating of Electroless Ni-W-P Ternary Alloys
Authors: Yao Huai , Zhu Guang Lin , Du Meng
Published: February 2011

The ternary Ni-W-P alloy coatings were deposited on the surface of Q235 steel using Chemical deposition. The microstructure, phase analysis, plating velocity and hardness were investigated with scanning electron microscope, X-ray diffraction technique and Vickers hardness tester. The results showed that the plating rate had been increased firstly, and then decreased with the increment of sodium citrate concentration in the range of 20-80g/L, the maximum plating velocity was 9.14μm/h. The hardness of Ni-W-P plating increased first and then decreased with the increment of sodium citrate concentration, the maximum hardness was 643HV when the concentration of sodium citrate was 40g/L. When the concentration of sodium citrate was 40g/L, the substrate was completely covered by Ni-W-P plating, the surface was composed of uniform crystalline grains, and had no obvious defects and presented amorphous. The coating and substrate were relatively strong, the coating had no the phenomena of fall off and crackle in the bending and files tests when the concentration of sodium citrate was 40g/L and 50g/L respectively.
Simulation of Two-Dimensional Transverse Laser Cooling of Cesium Beam from Pyramidal Magneto-Optical Trap Atom Funnel
Authors: Zhang Bao Wu , Porfido Nicolò , Tantussi Francesco , Fuso Francesco , Ma Yan , Zhang Wen Tao , Li Tong Bao
Published: February 2011

Simulation of two-dimensional (2D) transverse laser cooling of Cs atomic beam from pyramidal magneto-optical trap atom funnel (PMOTAF) conceived for atom lithography is presented. The results show that both the minimum full width at half maximum (FWHM) and the maximum peak value of the spatial profile of the atomic beam occur at the frequency detuning of optical molasses equals to -0.5 Г. Moreover, for each frequency detuning, an increase in the intensity of the optical molasses leads to smaller FWHM and higher peak value. The not negligible role of gravity on the atomic beam of sub-thermal longitudinal velocity along the horizontal direction is that every atomic trajectory possesses a parabolic motion either before or after laser cooling which leads to a noticeable displacement of the peak value at the observation plane with respect to the starting point.
Photodetection Technology Based on Laser Coding Emission
Authors: Guo Jing , Zhang He , Zhang Xiang Jin , Wang Xiao Feng
Published: February 2011

For the extremely weak echo signal and the poor anti-interference ability of the long-distance laser fuze, the high signal noise ratio (SNR) receiving system based on laser coding mode was designed. In order to improve the weak signal receiving ability, the avalanche photodiode (APD) with high sensitivity, low noise and high gain was adopted. And the optimum multiplication factor of APD when the system obtains the highest SNR was analyzed and calculated. Then, the amplifying circuit optimum matching with APD and the decoding circuit were designed, and validated by the experiments. The theory and experiment results indicate that the design is efficiency and capable to the long distance laser fuze, the system can exactly decode the weak laser coding signals received and export the ignition signal.
Research Progress of Laser Assisted Liquid Compound Machining
Authors: Yuan Gen Fu , Zheng Wei , Chen Xue Hui , Ma Yu Ping
Published: February 2011

Laser combined machining is a complex machining method which utilizes the combined effect of various forms of energy to achieve a material processing. High manufacturing quality and surface accuracy, and machining efficiency can be achieved. The research progress in the area of laser combined other machine processes is reviewed. Several methods of laser combined machining are introduced and their characteristics and applications from the point of the laser assisted liquid machining are investigated. For example, laser assisted wet etching and laser assisted jet electrochemical machining, and waterjet-guided laser machining are reported. The experimental and theoretical studies of the technologies to improve the machining performance are discussed. Finally, the existing problems and the future research directions of the laser compound processing are put forward .
Numerical Investigation of Dual Heating in Laser Micro-Adjustment of Actuators
Authors: Shen Hong , Hu Jun , Yao Zhen Qiang
Published: February 2011

Laser micro-adjustment as application of laser forming is a contact less and easily automated technology able to cause very small changes in shape to achieve high accuracies. In this study, a method using dual heating is introduced to reduce the temperature gradient across the thickness during laser micro-adjustment of actuators. The temperature field and deformation behavior using dual heating method are analyzed using a 3D finite element model. The in-plane angles are compared between using single heating and dual heating and the numerical results show that the in-plane angle using dual heating method can be predicted by the results by single heating.
Microstructure and Microsegregation in Directionally Solidified FeCoNiCrAl High Entropy Alloy
Authors: Cui Hong Bao , Wang Hai Yan , Wang Jin Yong , Fu Heng Zhi
Published: February 2011

Directional solidification (DS) of FeCoNiCrAl high entropy alloy is carried out to investigate the microstructures and microsegregation under controlled solidification conditions. With an increasing solidification rate, the interface morphology grows in a planar, cellular and dendritic manner. The microstructures of the dendritic and interdendritic segregation areas are found to be spherical precipitates and basket-weave structures, respectively. With the help of an electron microprobe, microsegregation is determined in directionally solidified FeCoNiCrAl high entropy alloys. In contrast to the as-cast condition, directional solidification can refine microstructures of FeCoNiCrAl high entropy alloy dramatically and reduce microsegregation effectively.
Experimental Research on the Semi-Solid Formability of 7A09 Aluminum Alloy Impeller
Authors: Han Fei , Wang Wei Wei , Luo Shou Jing , Du Zhi Ming
Published: February 2011

The impeller is an important component applied in airplanes, ships and weapons. It is difficult to form the complicated geometry of the impeller by using the conventional forging and casting technology. Semi-solid forming is a promising forming process that can produce complicated and high-quality components of wrought aluminum alloys. In this paper, the formability of the impeller was investigated by using advanced semi-solid forming technology and self-designed combined die, as well as quick forging hydraulic press. Experimental results show that the formability of the impeller increases with the increase of reheating temperature and holding time of the billet. When heating temperature and holding time during the pretreatment of the billet were 620°C and 25 min respectively, reheating temperature and holding time of the billet before thixoforging were 600°C and 90 min respectively, preheating temperature of the die was 320°C , the impeller was formed perfectly on the quick forging hydraulic press.
Analyses of Interfacial Thermal Stresses for DLC/WC-Co
Authors: Zhang Jun , Li Yang , Wei Xin Li
Published: February 2011

Thermal expansion mismatch is the most important which leads to the film/substrate interface damage and destruction. In this paper, the interface stresses analyses was conducted using Airy functions for the diamond-like carbon (DLC) film/ tungsten cobalt alloy(WC-Co) substrate structure; according to stress-strain relation, obtain the interface stress expression by substituting into the boundary conditions for giving parameter. The calculation results were analyzed and compared with the FEM simulation.
Microwave-Assisted Leaching Vanadium from Stone Coal
Authors: Ma Hong Zhou , Lan Xin Zhe , Wang Yao Ning , Tian Yu Hong
Published: February 2011

Technological process of microwave-assisted leaching of vanadium with sulfate solution has been defined on the base of phase and chemical constituents of stone coal. The influence factors such as content of sulfuric acid, microwave power, and leaching time were studied on leaching rate of vanadium from the stone coal. One element experiments and orthogonal design experiments are carried out to achieve optimized parameters. The experimental results showed that the leaching rate of vanadium was improved by the change of influence factors at some range. The single leaching rate of vanadium reached 80.9% under the optimal conditions of sulfuric acid content of 12%, microwave power 539w,leaching time of 2h.
Casting Solidification Behavior of Bimuth in Free-Cutting Copper Alloy
Authors: Liu Bai Xiong , Zhang Li Na
Published: February 2011

Effect of bismuth on the microstructure and performance of Cu-Se-Bi brass were studied. The microstructure analysis and fracture observation indicated that the content of bismuth has obvious effect on the foundry property of Cu-Se-Bi brass. The bismuth distributes on the boundary of α and β phrase and when the content of bismuth is below 1.0wt%,bismuth freezes on the phrase boundary in form of granule; when the content of bismuth amounts to 2.0wt%,bismuth presents in form of blocks; while when the content of bismuth is beyond 2.5wt%,bismuth lies on the phrase boundary in form of continuous films. The solidification mechanism of bismuth in Cu-Se-Bi brass was discussed through the thermodynamics analysis.
Numerical Simulation on Splat-Quenched CuCr25 Alloys
Authors: Zhou Zhi Ming , Lei Bin Bin , Tang Li Wen , Zhou Tao , Hu Yang , Cao Min Min
Published: February 2011

The numerical simulation model of rapid solidification splat-quenching CuCr25 alloys was built in this paper. The vacuum chamber, cooling cooper plate and sample were taken into account as a holistic heat system. Based on the heat transfer theory and liquid solidification theory, the heat transfer during the rapids solidification process of CuCr25 flakes prepared by splat-quenching can be approximately modeled by one-dimensional heat conduction equation, so that the temperature distribution and the cooling rate of the flake can be determined by the integration of this equation. The simulative results are coincident very well with the experimental results for the microstructure of rapid solidification splat-quenched CuCr25 alloys.
Interrelation between Microstructure and Mechanical Properties of Heavy Section Ductile Iron Casting
Authors: Diao Xiao Gang , Ning Zhi Liang , Cao Fu Yang , Ren Shan Zhi , Sun Jian Fei
Published: February 2011

The microstructures and mechanical properties of a sector ductile iron casting with a wall thickness of 500 mm were investigated. Results show that spheroidal graphite is obtained in ductile iron, and chunky graphite is avoided because of chills used during solidification. Besides, the matrix structure is nearly a full ferrite structure at the edge of casting while some pearlite forms at the center of casting. The competing effect between graphite and matrix structure keeps the strength relatively inert to the change in solidification time or cooling rate, but these two parameters both impair elongation of ductile iron as well. The samples with full ferrite matrix exhibit a typical ductile fracture mode while those with some pearlite lead to a mixed ductile-brittle fracture mode. Graphite internal fracture or graphite/matrix interfacial cracking are two crack initiation sites.
Preparation by Electroless Plating and Electromagnetic Shielding Effectiveness of Ni-Cu-Coated Calcium-Magnesium Silicate Whisker
Authors: Guan Deng Gao , Sun Chuan Min , Lin Jin Hui , Sun Yao , Xu Guan Li , Lei Ting
Published: February 2011

A new kind of Ni-Cu-coated calcium-magnesium silicate whiskers was prepared by electroless plating and characterized by EDS, SEM and XRD. And the preparation and shielding performance of a new kind of Ni-Cu-coated calcium-magnesium silicate whisker/nickel powder/epoxy resin electromagnetic shielding coatings were explained. The study results show the Ni-Cu-coated whisker with micro-sized spinal structure contains 12.4 wt% Ni and 1.35 wt% Cu. When the coating layer thickness is 300 μm, the shielding effectiveness of the coatings containing 4 wt% Ni-Cu-coated calcium-magnesium silicate whisker is up to 39.24-48.52 dB and increased an average of 10.38 dB compared with the nickel powder/epoxy resin electromagnetic shielding coatings in the frequency range of 0.3-1000 MHz. This offers a new idea to raise the levels of the comprehensive utilization of mineral resources and the prevention of electromagnetic environmental pollution.
Smelting Technology in Electric Furnace for Thick and Large Gray Iron with High Strength
Authors: Tang Hong Qun , Wei Hong Yu , Wu Lu Shu , Hu Shan Shan
Published: February 2011

Aiming at large and thick automobile die casting as well as combining with production practice, the main factors which influence the strength of gray iron in electric furnace are investigated and the smelting technology of electric furnace for thick and large gray iron with high strength is proposed in this paper. The result shows that the tensile strength of attached test specimen or hardness of casting can meet the application requirements greatly. This smelting technology provides reference for large and thick castings smelting under similar conditions.
Effects of Spinning on Microstructure and Mechanical Properties of A356 Alloy
Authors: Zhao Wen Min , Jia Xiao Fei , Wang Zhi Feng , Yin Zhi Gao , Xiong Guo Yuan
Published: February 2011

The tube-shaped parts of A356 alloy were deformed from 0% to 83% by spinning process. The microstructure and mechanical properties of A356 alloy were discussed. The results showed that as the wall thickness reduction increases, the dendrite cells of cast alloy are lengthened gradually and the average Secondary Dendrite Arm Spacing (SDAS) is reduced from 37.2μm to 23μm and eutectic silicon particles are distributed orderly along the spinning direction. The coarse acicular β-Al5FeSi is broken into many sections, and its length is reduced from 37.5μm to 12.5μm in the cross-section. The tensile strength and elongation exhibit a strong dependence upon the variation in wall thickness, with a parabolic relationship. The tensile fractured surface of parts with deformation ratio above 35% exhibits many equiaxial dimples, with intergranular ductile fracture mode.
Effects of Submerged Heater on the Vertical Bridgman Crystal Growth
Authors: Lu Ming Fang , Chuang Shu Hao , Lee Hsing Juin
Published: February 2011

This study used numerical simulation to investigate the growth conditions of yttrium aluminum garnet (YAG) single crystals by the vertical Bridgman method, and discusses the process performed with or without the installation of a submerged heater (SH). The maximum flow velocity of the melted material surrounding the melt/crystal interface can be decreased, and the deflection of the melt/crystal interface can be changed under various furnace temperature gradients and distances. The minimum of the maximized flow rate indicates that the natural convection can be decreased and controlled. In this manner, the growth rate of crystals increases in an identical environment.
Study on Unidirectional Solidification of Slab Ingot for Special Heavy Plate
Authors: Peng Xing Dong , Hu Lin , Wang Pei Xin , Zhao Lian Gang
Published: February 2011

Unidirectional solidification is a method of producing slab ingot for special heavy plate, when compression radio is more than 2.5, internal soundness of slab ingot is assurance, and the nature of Z orientation and percent of pass through supersonic flaw detecting are increased. Products are used in oil drilling platform in ocean ,separator of steam turbo-alternator with more than 0.6 million kW, anchor gate of large-scale hydropower station, shell of nuclear power plant, armoured plate of aircraft carrier. According to dissection on 28t large-sized slab ingot, simulation experiment of crystal, and analogy calculation of heat transfer and coagulation with CFX software, histology features and key to manufacturing technology of large-size unidirectional solidification slab ingot were mastered.
Arsenic Removal from Wastewater Using Adsorptive Mediums
Authors: Peng Fu Quan , Xu Zhen Cheng , Huang Jian Hong , Guo Qing Wei , Nie Feng
Published: February 2011

Different adsorptive mediums and adsorbents’ compounds were chosen to remove arsenic from Yangzonghai Lake wastewater. Results showed that Ca(OH)2, attapulgite, bentonite, LDHs these adsorptive mediums had adsorptive capacities of less than 2.5 mg/g of As removal and it took long time for sediment before monitoring; adsorbents compounds’ results showed Fe2O3 and quartz sands had best removal rate and quartz sands had little removal of arsenic. Both strong anion resin and hydrated ferrous oxide-loaded on polystyrene diethanolamine resin(designated as PDR-HFO) can decrease As concentration to less than 0.01 mg/L reaching national standards for arsenic; anions such as SO42- can not be removed when strong anion resin was regenerated causing its loss of exchange ions; PDR-HFO exhibited excellent adsorptive properties and recyclability.
Parameter Calibration Method Based on Screw Theory for Articulated Coordinate Measuring Arm
Authors: Huang Kui , Liu Rong Guang , Wu Jian Sheng , Lao Xin Rong , Mo Jian Hua
Published: February 2011

To improve the measurement accuracy of the articulated coordinate measuring arm (ACMA), the measurement system’s parameters must be calibrated. The mathematical model and the disturbance of the kinematic parameters’ error are critical to the calibration precision. In this paper, product-of-exponential(POE) model is adopted to establish the kinematic model of the ACMA, and an error correction model which utilizes single-point versus multi-pose and the distance between every two points is used to take accuracy and repeatability into account. Then, genetic algorithm is utilized to optimize the error correction model in order to identify kinematic parameters. Experimental results reveal that the proposed calibration method is feasible.
Sapphire-SiO2 Solid-Phase Reaction of Polishing Proving Research
Authors: Zhou Zhao Zhong , Li Zhen , Deng Qian Fa , Wang Ji Cui , Yuan Ju Long
Published: February 2011

The solid-phase reaction experiment and principle were introduced. 1000# SiO2 micromist and CaO powder were used polishing sapphire, with polishing pressure 7.5kPa，polishing speed 60r/min and 40r/min. The process of polishing was separated every 120 minutes. The surface appearance and roughness will be survey in each part. Non-surface-scratch will be achieved after 600min of polishing. The roughness (Ra) was decreased from 395nm to 7nm. Rmax was decreased from 2.98μm to 0.05μm. Rt was decreased from 3.34μm to 0.05μm. Through the analysis of the experimental data of XRD, kyanite phase map and diffraction pattern fitting degree. The fact that quality of sapphire’s surface was improved by using this approach has been proved.
Development of an Ultrasonic-Vibration Microforming Apparatus
Authors: Hung Jung Chung , Shieh Ching Shyong
Published: February 2011

This study attempted to design and develop an integrated system of a microforming apparatus with ultrasonic-vibration device. A closed-loop displacement and force control was implemented with servo motors. The apparatus has a load capacity up to 10,000N. The displacement error curve of the platform was measured with API 5DLS laser interferometer, and fed into the control program to compensate for motion errors. The positioning precision of the platform has been upgraded up to 5μm, with a load accuracy of 0.5N. Taking advantage of FEA and optimization technology, boosters and resonator with 35 kHz frequency were designed and fabricated. The simulation results and the experimental results match perfectly on the account of resonance frequencies and amplitudes. To the end, the integration of the ultrasonic-vibration device with microforming platform demonstrates a precision process for micro-parts.
Study on Accurate Tool Positioning Technology for Noncircular Turning System
Authors: Li Guo Ping , Han Tong Peng , Shu Li Sheng
Published: February 2011

Noncircular turning is necessary for machining various irregular shaped workpieces. Tool positioning control is essential for a noncircular turning system. This paper proposes a method of accurate tool positioning based on piezoelectric ceramics micro-displacement actuator. A Duhem hysteresis model of piezoelectric actuator has been developed, together with a control model of accurate positioning system. By using Simulink/Matlab, the control system was simulated, and then tested on a test-bench. The results show that the positioning time of control system is 0.1 seconds and the error rate of positioning accuracy is less than 5%, which can meet the accuracy positioning requirements of the noncircular turning system.
Ultrasonic Grinding Three-Dimensional Trajectory Simulation and Experimental Study
Authors: Zhao Bo , Ma Jun Jin , Bian Ping Yan , Li Yu
Published: February 2011

In this paper the relationship of the efficiency of ultrasonic grinding and abrasive movement are studied. Ultrasonic grinding grain three-dimensional trajectories were simulated based on MATLAB software in the paper, and micro-grinding surface states were observed with SEM. Therefore, the influence law of ultrasonic vibration to the grinding surface texture is received. The results show that: Compared with ordinary grinding, the workpiece grinding surface texture quality and the grinding efficiency have been significantly improved under the condition of ultrasonic vibration.
The Installation Eccentricity Error Compensation Technology for Gear Based on CNC Gear Measuring Center
Authors: Han Lian Fu , Ma Qiang , Tang Wen Yan , Fu Chang Feng
Published: February 2011

In order to decrease the influence of installation eccentricity on gear error evaluation and to raise its accuracy, a compensation algorithm for installation eccentricity is proposed and a compensation model of installation eccentricity is established. A new installation eccentricity parameter identification method determined with involute equations is also raised. Installation Eccentricity parameters are gained through measuring points on involute profile with the method of unconstrained parameter identification. Taking involute profile evaluation as an example, the eccentricity compensation model is introduced into the error evaluation of CNC Gear Measuring Center. The experiment shows that the compensation model raised in this paper can compensate for evaluation results of the involute gear whose eccentricity value is within 2/3 of the total measurement range of the probe and lead it into the non-eccentricity condition, and the most installation eccentricity value that can be compensated in the experiment is 300 μm. The proposition of this compensation method not only improves the accuracy of gear evaluation, but also lowers the requirements on installation accuracy of the gear.
Technology of Tooth Pitch Deviations Measurement for Master Gears of Precision Grade 1
Authors: Ma Yong , Wang Tong Xiang , Li Ke Hong , Fan Suo , Wang Li Ding
Published: February 2011

In order to solve the difficult problem of detection of pitch deviations of high-precision master gears, a new measuring instrument is developed. Detail description about measuring apparatus of pitch deviations developed for master gears was presented in the paper. Computer aided technology was used to deal with data collected by computer, and error analysis about the measuring apparatus was introduced, which affected measurement accuracy. The results confirm that the measuring apparatus is able to meet measurement requirement and improve efficiency through the measuring experiments on master gears of precision grade 2 and 1 with modulus 2 mm and 2.5 mm, respectively. And the uncertainties of single pitch deviation and total cumulative pitch deviation are 0.07and 0.26, respectively.
Study on Ultrasonic Cavitation Mechanism of Honing
Authors: Liu Guo Dong , Zhu Xi Jing
Published: February 2011

Ultrasonic cavitation is an extremely complex physical phenomenon. It displays a series of nonlinear dynamics as the bubbles oscillating, growth, shrinkage and even collapse. For ultrasonic honing, it causes the device to generate chatter and noise because of the cavitation effect, and even generates denudation on the workpiece surface. In this paper, it describes the cavitation mechanism in ultrasonic honing, and analysises the acoustic pressure of the formation of cavitation from the numerical, furthermore it experimentally demonstrated. It also analyzes the nonlinear oscillation of cavitation bubbles for the impact on the ultrasonic honing chatter. Through studying on ultrasonic cavitation mechanism of honing, it provided a theoretical basis to solution the problem of the ultrasonic honing chatter and improves the level of precision and ultra precision machining.
Billet Design Optimization of Helical Gears Precision Forging Based on Response Surface Method and FEM Simulation
Authors: Feng Wei , Mei Yun Feng , Yan Kang , Zou Tian , Zhang Xin Lei
Published: February 2011

Billet is designed by utilizing the flow relief-hole principle to improve the dimensional accuracy during the precision cold forging of helical gear . An optimization method for the initial diameter of the relief-hole was proposed based on the finite element method(FEM) and response surface method (RSM). The degree of uniformity of effective strain in helical gear precision forging was considered as the optimal objective. The empirical equation built through Response Surface Method shows the relationship between the the initial diameter of the relief-hole and the degree of uniformity of effective strain. The optimal diameter is obtained through gold section method based on the empirical equation . The optimal result has been verified by using the commercial software DEFORM 3D.
A Vision Alignment Method Based on Improved Genetic Algorithm for IC Packaging
Authors: Liu Shi Wei , Li Jun Lan , Zhao Xing Yu , Zhang Da Wei
Published: February 2011

In order to improve the speed and accuracy of vision alignment for IC packaging, genetic algorithm and Otsu method are applied to vision alignment. According to the features of the image in IC packaging, an improved self-adaptive genetic algorithm combined with Otsu method is proposed in this paper, and the moment invariants method is used to carry out the remaining steps of vision alignment. Finally, experiments are undertaken by using a kind of IC chip, results show that the positioning error is less than 2μm, and the positioning time is less than 60ms.
Improved Genetic Algorithm Based on Operation Order Matrix Encoding for Job Shop Scheduling Problem
Authors: Zhan Hong , Yang Jian Jun , Ju Lu Yan
Published: February 2011

This paper presents an improved genetic algorithm for the job shop scheduling problem. We designed a new encoding method based on operation order matrix, a matrix correspond to a chromosome, the value of elements is not repetitive, that means a processing order number in all operations of all jobs. Aiming at the features of the matrix encoding, we designed the crossover and mutation methods based on jobs, and the infeasible solutions are avoided. Through adjusting the computing method of fitness value, the improved genetic algorithm takes on some self adapting capability. The proposed approach is tested on some standard instances and compared with two other approaches. The computation results validate the algorithm is efficient.
Wire Electrical Discharge Machining – High Speed VS Abrasive Waterjet - A Case Study
Authors: Zhang Shi Jin , Wu Yu Qiang , Wang Yan Li
Published: February 2011

Technological advancement, on the one hand, made Electrical Discharge Machining (EDM) much faster. One example of that is the presence of Wire Electrical Discharge Machining – High Speed (WEDM-HS) machine, which makes the material removal rate as high as 80 . On the other hand, it also made Abrasive Waterjet (AWJ) achieve much better quality surface and tighter tolerance. As a result, these two types of machining process have converged to the point where they can complement one another quite nicely in selected applications. However, it does not mean user may pick any one for their applications. The proper selection not only decreases the manufacturing costs but also achieves better quality. This paper focuses on comparing WEDM-HS with AWJ by actually cutting a special designed sample. Through comparison from several aspects which include dimension precision, surface roughness, cost, cutting time and surface damage, a proper selection guidance for regular user has been provided.
The Structure and Electrochemical Properties of BDD Deposited on Ti Substrate by MWCVD
Authors: Liu Feng , Wang Wen Jun , Wang Jun Tao , Xiong Li Wei , Xin Yong Lei , Li Xiang Bo
Published: February 2011

In this paper, Boron doped diamond (BDD) thin films have been deposited on Ti substrates by microwave plasma chemical vapour deposition (MWCVD). Raman spectroscopy scanning electron microscopy (SEM) and X-ray diffraction (XRD) examinations demonstrate that the electrode has well-defined diamond features. It is observed that the BDD electrode has a high overpotential 2.5V for water electrolysis prohibiting the evolution of oxygen in the cyclic voltammetry test. Further more，the removal efficiency of chemical oxygen demand (COD) is evaluated by the electrochemical oxidation of wastewater containing phenol.
Study on Salt Fog Corrosion of FeCoCrMoCBY Amorphous/Nanocrystalline Alloy Coating
Authors: Zhou Xian Liang , Hu Lin Li , Chen Qing Jun , Hua Xiao Zhen
Published: February 2011

Fe-based amorphous alloy coating with a composition of Fe41Co7Cr15Mo14C15B6Y2was prepared by high velocity fuel(HVOF) technique. The influence of heat treatment on crystalline behavior, the phase structure and corroded morphology of the coating was investigated by Differential Thermal Analysis(DTA), X-ray Diffraction (XRD), Scanning Electron Microscopy(SEM), respectively. The experimental results indicate that the amorphous alloy coating exhibited a two-step crystallization process with crystallization peak temperature at 698°C and 822°C, respectively. Amorphous coating exhibits excellent corrosion resistance than that of the corresponding nano-crystalline coating with heat treatment at 700°C for 2h, 8h and 12h. Furthermore, the nano-crystalline coating annealed 700°C for 12h suffers slight homogeneity corrosion, which did not exhibit obvious pitting on comparison with coating holding 2h and 8h.
The Life-Span Prediction of Reinforcing Bars Corrosion of Self-Compacting Concrete
Authors: Li Yue , Yan Chao , Du Xiu Li , Zhang Yong , Lei Qiao
Published: February 2011

Self-compacting concrete (SCC) has been used widely. However, the study of life-span prediction of self-compacting reinforced concrete is not enough under chloride ion corrosion condition， For the reinforcing bars corrosion that chlorine ions invade into SCC，the life-span prediction of Self-Compacting Concrete is the key issue. In this paper, the life-span prediction model of SCC structure under chloride ion corrosion condition is established and used to analyze the life-span prediction of SCC samples. Prediction results matched the test results very well, which shows the rationality of this prediction formula.