bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Modeling of Randomly Distributed Multi-Walled Carbon Nanotube/Polymer Composites
Authors: Li Xiao Tuo , Fan Xin Yu , Zhu Ying Dan , Li Juan
Published: July 2012

A three-dimensional computational model based on the finite element method was developed to predict the thermal properties of randomly distributed multi-walled carbon nanotube (MWCNT)/polymer composites. The numerical results agree very well with the experimental data for MWCNT/epoxy composites with the MWCNT loading below ~10 vol% at the interfacial thermal resistance of ~1.0×10-8 m2K/W, which may give insight into the relationship between the thermal behavior of MWCNT-matrix interfaces and the thermal conductivity of composites. This model is also a useful tool to evaluate the effects of MWCNT-matrix interfacial thermal resistance, volume fraction, thermal conductivity and diameter of MWCNTs on the thermal conductivity of other types of MWCNT/ polymer composites.
Fabrication and Characterization of Degradable Biomaterial Block Polymer PLGA Nanoparticles Modified by MePEG
Authors: Guo Da Dong , Bi Hong Sheng , Xie Xiao Feng
Published: July 2012

The block polymer methoxy(polyethylene glycol)-poly(dl-lactide-co-glycolic acid) (MePEG-PLGA) nanoparticles were fabricated by modified spontaneous emulsification/solvent evaporation method, and further characterized their shape, size, zeta potential, glass transition temperature and other items by scanning electron microscopy, laser granulometry, differential scanning calorimetry (DSC), fourier transform infrared spectrometer and differential scanning calorimeter. Meanwhile, the effects of cytotoxicity of MePEG-PLGA nanoparticles on human ARPE-19 cells. The results indicated that the mean size of MePEG-PLGA nanoparticles was about 368.1nm, zeta potential was -32.6mV in distilled water and the start of glass transition temperature 26.75 centigrade degree. The fabricated MePEG-PLGA nanoparticles had narrow size distribution and were block polymer of PEG and PLGA detected by fourier transform infrared spectrometer and have good physical- and chemical-characterization. Additionally, no cytotoxicity was found for the MePEG-PLGA nanoparticles on human ARPE-19 cells. These results indicated that MePEG-PLGA nanoparticles have good biocompatibility and could be applied in drug delivery.
Electrochemical Fabrication and Characterization of Iron Quantum Wire
Authors: Dong Xiao Dong , Liu Jun Hua , Xia Yong
Published: July 2012

Stable iron quantum wire with atomic-scale was successfully fabricated and electrically characterized with an electrochemical method in solution by a home-made electrochemically controlled system. By careful controlling the etching/deposition process, stepwise conductance behavior could be clearly observed. The I-V curve of the formed iron quantum wire showed the ohmic behavior with low bias voltage. The work is of great significance for molecular electronics, interface electrochemistry and sensing.
Theoretical Investigations of Methane Conversion to Heavier Hydrocarbons in a Plasma Reactor
Authors: Kazemeini Mohammad , Zare Masoud Habibi , Safabakhsh Nora , Ferdosi Shadi Roshdi , Fattahi Moslem
Published: July 2012

In this study, mathematical modelling of oxidative coupling of methane (OCM) to C2hydrocarbons (C2H6and C2H4) over La2O3/CaO catalyst in a fixed-bed reactor operated under isothermal and non-isothermal conditions was investigated using the MATLAB program. In this process, methane and acetylene were the inputted feed and ethane, ethylene, propylene, propane, i-butane and n-butane were the output products. The amount of methane conversion obtained was 12.7% for the former feed however; if pure methane was inputted this conversion rose to 13.8%. Furthermore, the plasma process would enhance the conversion, selectivity towards desired product and process yield. A comparison between the thermal and the plasma process showed that the methane conversion and production yield in the plasma were higher than in the thermal process under the same operating conditions. Finally, the results of the catalytic OCM and methane conversion processes in the plasma phase were compared with one another.
Thermo-Mechanical Coupled and Fracture in Diamond Film under High Strain Rate
Authors: Tang Da Pei
Published: July 2012

According to the special case of high strain rate for diamond film produced by DC plasma jet method, a transient thermo-mechanical coupled model for the cooling process of diamond film and Mo substrate was developed. The direct coupled finite element method was used to simulate the transient thermal stresses in diamond film during the cooling period after the film deposition. The residual thermal stresses of diamond film were calculated and compared respectively under two conditions of real uneven temperature fields and unreal even temperature fields. Based on the simulated results of stresses, the moment and cause of diamond film cracking were analyzed. The conclusions are as the follows: (1) the thermal stresses in diamond film increase with the increase of cooling time, but the maximum first principal tensile stress may reach the fracture strength of common diamond film before the film cools to room temperature; (2) the excessive tensile stress at the film edge causes the film cracking; (3) in order to reduce the thermal (residual ) stresses and increase the finished product ratio of diamond film, it is essential to further improve the temperature uniformity.
Research on the Energy Properties of the Hydro-Reactive Metal Fuel
Authors: Zhu Rui , Zhang Zhen Shan , Shan Xiao Liang , Liang Wei Ge
Published: July 2012

Contrast the energy properties of many kinds of chemical propellants, it is obvious that the metal fuel reacting with water has huge superiority and vast application foreground. Under the hypothesis condition, the burning model of the metal fuel reacting with water is analyzed. The energy properties of the metal fuel are researched through the way of thermodynamics computation, containing the burning time, reaction principle, and the reacting temperature.
Strain Rate Sensitivity of an Aluminium Alloy under Compressive Loads
Authors: Singh Nilamber K. , Singha Maloy K. , Cadoni Ezio , Gupta Narinder K.
Published: July 2012

An experimental investigation on the dynamic compressive behaviour of the aluminium alloy, AA6063-T6 in the strain rate range from 0.001s-1 to 850s-1 is reported here. Cylindrical specimens of AA6063-T6 are tested under universal testing machine at quasi-static (0.001s-1) condition, whereas, experiments at high strain rates (110s-1,400s-1,550s-1,700s-1 and 850s-1) are conducted on the traditional split Hopkinson pressure bar setup. The strain hardening in the material is found to increase with increasing strain rate. It is observed that the existing Johnson-Cook material model with appropriate material parameters predicts the dynamic compressive flow stress of AA6063-T3 aluminium alloy precisely.
Finite Element Modeling of Ceramics Particles Reinforced Aluminum Alloy Composites under Forward Extrusion
Authors: Suranuntchai Surasak
Published: July 2012

Finite Element Method (FEM) has becoming more influences in analyzing and solving metal forming problems from the beginning of punch and die designed up to setting the appropriated surrounding constrains in the deformation processes. This research was concerning about the study of simulation in cold forward bar extrusion of some aluminum alloys reinforced with ceramic particles using a commercial FE program; MSC. Marc to enhance the analysis. Two most important parameters in extrusion were investigated, which included area reduction ratio, εA, and die angle, 2∂, that affected to the forming force in the workpiece. In this research, the matrix part of composites studied was varied as follow: AA6061, AA6082 and AA230A reinforced by particles of SiC and Al2O3. Also, the volume fraction of reinforcement was another material parameter needed for the study. The dimension of initial billet in the simulation had 24.7 mm of diameter and 30 mm of length. The punch and die were assumed to be rigid which neglected the deformation. In case of heat dissipation, they were not considered in this simulation; therefore, the process assumed to be done isothermally at room temperature of 20°C. From the modeling results, the suitable conditions for different parameters were obtained, which assisted to the consideration of appropriated forward bar extrusion processes of such particulate reinforced Metal Matrix Composites (MMCs).
Determination of Geometric Shape of the Molecular Surface
Authors: Zhang Jing Qiao , Luo Wen
Published: July 2012

A new type of compound can be got by docking the active site of acceptor and the active site of ligand. In general, active sites of the molecule are often located in the concave-convex regions. In this paper, we propose a new method which combines discrete Gaussian curvature with normal to determine geometric shape of the molecular surface of protein. Firstly, we compute the normal and Gaussian curvature of all vertices of the triangular mesh model that present a molecular surface. Then we choose a certain number of vertices ac-cording to Gaussian curvature of each vertex on the mesh. By doing so, the shape of the region consisting of those vertices is determined, that is the region is concave or convex.
Effect of Titanium on the Precipitating Behavior of Inclusions and Corrosion Resistance of Niobium Stabilized 409 Ferrite Stainless Steel
Authors: Zhu Cheng Yi , Zheng Jian Xin , Li Guang Qiang , Zheng Wan
Published: July 2012

In order to investigate the effect of titanium addition on the precipitating behavior of inclusions and corrosion resistance of niobium stabilized ferrite stainless steel, experiments were conducted in a high frequency vacuum induction furnace for smelting titanium and niobium stabilized ferrite stainless steel in argon atmosphere, and the composition, morphologies and size of inclusions in the samples were investigated. Precipitating behavior of the inclusions and intergranular corrosion resistance of the samples were analyzed by CSLM. Corrosion resistance of the steel in 2% NaHSO3 solution was tested by using electrochemistry comprehensive test instrument. The results show that inclusions in the as cast steel mainly are rectangle TiN, TiC, NbC and complex inclusions with TiN or TiC as core packed by NbC, and their size is about 1~5μm. There are a few nearly spherical complex inclusions with Al-Mg-Si-Ti-O as core packed by TiN, TiC, NbC or their complex inclusions. The spherical inclusions become rectangle with the increase of titanium addition, and the quantities of inclusions which size is larger than 5 μm increase. Precipitates increase during heat treated and grain size of the steel becomes a little smaller with the increase of titanium content in the steel. The grain boundary of the steel becomes stabilization and intergranular corrosion resistance enhances with the increase of titanium content in the steel according to the online analysis results. Passivation current density of the steel becomes smaller and passive potential range becomes wider in 2% NaHSO3 solution at 30°C with the increase of titanium content in the steel which indicates corrosion resistance of the steel being enhanced.
Study on a New Glass Polishing Plate
Authors: Chen Jin Shen , Zhi Hong Mei , Wen Shao Guo
Published: July 2012

This paper reports a polishing disk which can substitute for rare earth. Using alumina - cerium oxide core-shell composite abrasive as abrasive, unsaturated resin as bonding agent, abrasive tool can be prepared by adding a water soluble pore-forming agent, suitable heat absorbing agent and active stuffing and the suitable addition amounts which are 25.6%, 46.8%, 18.5%, 3.8% and 1.2%, respectively .This abrasive tool can conduct the temperature in the grinding zone rapidly. It also has high grinding efficiency smooth polishing surface and without cracks or scratches, which meet furthermore, it has the merits of low cost and extensive use prospect. The polishing effect of rare earth polishing disk, but the low cost make it suitable for wide promotion.
Research on TDDB Effect in High-k Materials
Authors: Lu Feng Ming , Shao Jiang , Liu Xiao Yu , Wang Xing Hao
Published: July 2012

With continual scaling of ICs, the thickness of gate oxide becomes thinner and thinner which affects the reliability of semiconductor device greatly. The mechanism of time-dependent dielectric breakdown (TDDB) was analyzed. Six mathematical models of TDDB which were divided according to the position of defects and the physical property of charged particles were discussed. Then the dielectric breakdown characteristic of high k dielectrics and the relationships between the breakdown electric field, field acceleration parameter and dielectric constant were analyzed in detail. Finally, the relationships and mathematical models were verified by experimental data which provided theoretical basis for the choosing and use of high k materials.
Recycled Aggregate Concretes for Structural Applications: From Investigation to Design
Authors: Corinaldesi Valeria , Moriconi Giacomo
Published: July 2012

In this paper an investigation of mechanical behaviour and, in particular, elastic properties of recycled aggregate concrete (RAC) is presented. RACs were prepared by using a coarse aggregate made of old concrete particles coming from a recycling plant in which rubble from demolition of reinforced concrete structures is collected and suitably treated. Several concrete mixtures were prepared by using either the only virgin aggregates (as reference) or 30% recycled concrete aggregates replacing gravel, and by using two different kinds of cement. Different water to cement ratios were adopted ranging from 0.40 to 0.60, while concrete workability was always maintained at the same rate by adding different amounts of water-reducing admixture. Concrete compressive strength, elastic modulus and drying shrinkage were evaluated. Results obtained showed that structural concrete up to C32/40 strength class can be manufactured with RAC. Moreover, results obtained were discussed in order to obtain useful information for RAC structure design, particularly in terms of elastic modulus and drying shrinkage prediction.
The Change of L Edge of Electron Energy Loss Spectroscopy of Ni in Ni-Based Solid-Solution Alloys
Authors: Yang W.G. , Cheng Y.
Published: July 2012

The electron energy loss spectroscopy (EELS) of Ni in a series of Ni-based solid-solution alloys and pure Ni has been collected. It is found that the distance between L2 and L3 peaks of Ni EELS is enlarged in all alloys relative to pure Ni. The d-electron occupancy of Ni in all alloys is measured from the white-line intensity of EELS and the results vary very small.
Dynamic CCT Curve of Hot Deformation Austenite in 55SiCr Steel
Authors: Zhang Yong Jun , Cui Chuan Da , Han Jing Tao
Published: July 2012

The CCT (Continuous Cooling Transformation) curve of hot deformation austenite in 55SiCr steel was measured on Gleeble-1500 thermal simulation machine, the microstructure and hardness of transformation products under different cooling velocities were observed. The microstructure transformation regularity with being cooled continuously were emphatically researched at the cooling rate form 0.1°C/s to 15 °C/s. The results can provide a instruction for producing 55SiCr steel.
Rapid Determination of Chromium in Diamond Tools
Authors: Zhi Hong Mei , Chen Jin Shen , Wen Shao Guo , Cheng Wen Xi
Published: July 2012

This paper draws out a new method to determine the chromium content in diamond tools of metal bond. Used aqua regia to dissolve the sample, perchloric acid emits smoke to oxidize the Cr3+ to Cr2O72- by smoke emission .than used reducing agent of Fe2+ standard solution to measure quickly the chromium in the diamond tools of metal bond. This method is verified by quality control chart , this method saves time and practical.
XPS Characterization of Porphyrin Based Self-Assembled Monolayers on Gold
Authors: Liu Guang Yan , Wang Wen Cai
Published: July 2012

XPS characterization of self-assembled monolayers (SAMs) of tetraphenylporphyrin bearing a rigid tripodal linker by chemisorption of the thiol-derivatized terminal groups on gold substrate is described. The surface structure of the SAMs bearing tripodal linker were analyzed by X-ray photoelectron spectroscopy (XPS), and electrochemical cyclic voltammetry (CV) measurements. XPS confirms the formation of porphyrin SAMs on Au surface and identified bonding configurations of porphyrin molecules in the chemisorption of SAMs. The film thickness values (36 Å) obtained by XPS agree well with the estimated value by assuming the vertical orientation of the molecules on the gold surface. Using the Au4f7/2 as an internal standard, a lower binding energies shift (1.8 eV) of S2p in the SAMs reveals that the porphyrins were chemisorbed onto the surface via sulfurgold bonds. Electrochemical CV measurements suggest near monolayer coverage of the tripodal porphyrins with good stability of the redox SAMs, which have promising application in the development of molecular based electronic device and memory architectures.
Evaluation of Dina Aggregates for Pavement Construction in Pakistan
Authors: Arshad Hussain , Qiu Yan Jun
Published: July 2012

This paper presents the evaluation of the potential aggregate source for pavement construction in Pakistan. The Dina quarries which produce quartzite aggregates have been in use for building construction for long time. For pavement construction the aggregate materials are mostly obtain from Margalla hills and Kirana hills. The crushed limestone from Margalla source has been in use for both building and road construction from decades. The Kirana hills aggregates have been also used in many road construction projects in Punjab. The purpose of this research is to see the performance of Dina quarries as potential aggregates for pavement construction. For this purpose the Dina aggregate properties are compared with the Margalla aggregates which are most extensively use in pavement construction. The aggregate properties like specific gravity, water absorption, los angles abrasion, soundness, shape, crushing and impact value conform to the required pavement standards. The asphalt mixture design make with the Dina aggregate by Marshall method also shows suitable performance. These laboratory testing indicates that Dina quarries are potential aggregates for pavement construction in the Punjab province.
Enhanced Hardness Property in the Development of Al-TiC Composites through P/M Techniques
Authors: Solay Anand S. , Mohan B.
Published: July 2012

Powder Metallurgy is a continually and rapidly evolving technology, embracing most metallic and alloy materials with a variety of shapes. Weight percent of reinforcements and processing parameters plays a vital role in determining strength of the powder metallurgical parts. In this work, the effect of varying weight percent of particulate TiC reinforcement with elemental 6061 Aluminium alloy on mechanical properties of specimens processed through powder metallurgy has been investigated. Weight percent of TiC ranges from 1% to 10% and the specimens are compacted at 125 MPa and 175 MPa. With increase in the weight percent of TiC up to 5%, micro hardness and tensile strength value increases and there is a decrease in tensile strength value for a weight percent of 10 % TiC. Increase in compaction pressure from 125 MPa to 175 MPa, the density, hardness and tensile strength value increases.
The Research of De-Gassing with Silicon Powder Gapping for Remote Laser Welding of Zinc Coated Sheet Metal
Authors: Zhang Zhong Ning , Tian Jian
Published: July 2012

There are the four types of defects during remote laser welding of zinc coated sheet metal. The root cause of all these defects is the explosion or ejection of molten weld metal caused by the escape of trapped high pressurized zinc vapor. De-gassing gapping is a method used to solve the defects. We have researched the silicon powder de-gassing gapping method for remote laser welding with coupons of zinc coated sheet metal. The result shows that silicon powder de-gassing gapping method works well.
Study on the Manufacture of Microfluidic Chip with Coated Glass
Authors: He Yan , Huang Bai Ling , Zhang Yong Lai , Niu Li Gang
Published: July 2012

In this paper, a simple and facile technique for manufacturing glass-based microﬂuidic chips was developed. Instead of using expensive dry etching technology, the standard UV lithography and wet chemical etching technique was used to fabricate microchannels on a K9 glass substrate. The fabrication process of microfluidic chip including vacuum evaporation, annealing, lithography, and BHF (HF-NH4F-H2O) wet etching were investigated. Through series experiments, we found that anneal was the critical factor for chip quality. As a representative example, a microfluidic channel with 20 m of depth, and 80 m of width was successfully prepared, and the channel surfaces are quite smooth. These results present a simple, low cost, flexible and easy way to fabricate glass-based microﬂuidic chips.
An ANN Approach in Prediction of Microhardness in a Furnace Cooled Sintered P/M 6061 Aluminium Compacts
Authors: Solay Anand S. , Mohan B.
Published: July 2012

In this paper the effect of particle size of aluminium powder and furnace controlled cooling after sintering on porosity level and micro hardness of an elemental 6061 aluminium alloy has been investigated experimentally and the micro hardness value is compared with the Neural network algorithm using matlab. The algorithm used here are Gradient Descent Back propagation with Adaptive Learning Rate. Aluminium particle sizes of 20µm and 150µm were used. The elemental 6061 aluminium powders are warm compacted at 175MPa. After sintering for about one hour at 600°C, the aluminium compacts were furnace cooled at the rate of 1°C/min to different temperatures of 500°C, 400°C, 300°C and 200°C. When the cooling temperature after sintering inside the furnace is effected at various temperatures from 600°C to 200°C, for a precipitate hardened aluminium compacts with aluminium particle size of 20µm, the porosity level reduced by 26% and that for aluminium particle size of 150µm, the porosity level reduced by 23%. Marked improvement in micro hardness value is also observed correspondingly. Then the Neural Network was trained using the prepared training set which was recorded by the experimental values. At the end of the training process, the test data were used to check the accuracy result. As a result the Neural Network was found successful improvement in prediction of microhardness in a slow cooled sintered powder metallurgical 6061 Aluminium alloy.
Burr Minimization in Step Drilling of Al-Fly Ash/Gr Hybrid Composites by Taguchi Method
Authors: Shanmughasundaram P. , Subramanian R. , MahendraBoopathi M.
Published: July 2012

Metal Matrix Composites (MMCs) have emerged as a potential material especially for automotive and aerospace industries. In view of the growing engineering applications of these composites, the machining parameters have to be optimized in order to attain good surface quality, reduced tool wear and cutting forces. In this paper, the influences of the feed and step drill’s geometries such as step angle and step size on the exit burr height have been investigated for burr minimization in drilling of MMCs. Experimental study was conducted for Al-15wt.% fly ash composites and Al-15wt.% fly ash /1.5wt.% graphite hybrid composites which are fabricated through stir casting method. Optimum drilling parameters were identified for burr minimization by the application of Taguchi method, analysis of variance (ANOVA) and the results were validated by confirmation test. Results revealed that feed and step drill’s geometries step angle and step size were the most influential factors on the formation of burr. Dynamom¬eter was employed to measure the thrust that was being applied to the work piece when it was drilled. The inclusion of graphite as supplementary reinforcement in Al / fly ash reinforced composite reduces the thrust force and exit burr height considerably.
Influence of Admixtures on Performances of EPC Coating
Authors: Chen Shu Jiang , Zhou Yong
Published: July 2012

This paper studied the influence of CMC, sodium bentonite and white latex addition on the performance of EPC coating under the following conditions: sodium bentonite was used as high-temperature binder of the coating; CMC and white latex were used as low-temperature binder of the coating; right amount of water was added; and viscosity was controlled of 30-35 seconds. The results showed that the coating had good overall performance with 0.2-0.8% CMC addition, 3-9% sodium bentonite addition and 3-7% white latex addition.
Fractal Study on the Complexity of Limestone Surface Pore Structure
Authors: Wu Xin , Long Si , Li Guo Hui
Published: July 2012

Complex characteristics of pore structure of rock mass, such as limestone, are difficult to describe by means of general mathematics and physics. While, the fractal geometry can describe some simple rules behind complex phenomena; and these simple rules can describe the complex phenomena. Therefore in this paper, the fractal theory is applied to study the complexity of the limestone pore structure. Through calculating the fractal dimension of the limestone pore microscopic images of different zoom scales, the scale-independence is proved to be possessed by complexity of pore, which indicates that the limestone is a good fractal body, and its complexity can be studied by means of fractal dimension.
Structural and Electronic Properties of Small Silsesquioxanes: A DFT Study
Authors: Zhang Cheng Gen , Chen Ze Min , Yu Shu Yuan , Wei Hong Chao
Published: July 2012

Density functional theory (DFT) calculations are performed to investigate the structures of small silsesquioxanes (Si2nO3nX2n) (n=1-5 and X=H, F, Me). The large HOMO–LUMO gaps, which range from 5.41 to 9.17 eV, imply optimal electronic structures for these molecules. Furthermore, the substituent effect analysis indicate that the electron donating methyl group substituents lengthen the Si-O bond and largen the SiOSi bond angle, the electron withdrawing F atom substituents shorten the Si-O bond and lessen the SiOSi bond angle.
Effect of Surface Treatment on the Properties of Kevlar Fibers by a Novel Chemical Method
Authors: Jia Zhao , Yang Yan Gong
Published: July 2012

The surface of kevlar fiber was modified by phosphoric acid solutions (H3PO4) in this article. The structure and morphology of the modified fiber were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The results showed that some polar groups were introduced into the molecular structure of aramid ﬁbers. The interfacial properties of aramid fiber/epoxy composites were investigated by the single ﬁber pull-out test (SFP). The results showed that the interfacial shear strength (IFSS) of aramid/epoxy composites was remarkbly improved after surface modification and the breaking strength has not been affected appreciably. It provided an efficient method to make the surface modified Kevlar fiber for the application for the advanced composites at a lower production cost.
Development and Application of Reference Materials of Series of Copper Cathode
Authors: Yuan Huai Bao , Li Yue Hong
Published: July 2012

In accordance with the requirements of the reference materials technical specifications, refer to some countries’ existing standards of chemical composition of copper Cathode products, design the chemical composition of each reference materials. Using proper methods of batching, smelting technique and extrusion processes etc., developed a set of reference materials of copper Cathode. Determine the content of the various elements using a variety of methods by several laboratories. These samples are mainly used for the determination of Pb, Fe, Bi, Sb, As, Sn, Ni,, Zn, P, S in copper cathode and parts of copper by photoelectric direct reading spectrometry, plasma spectroscopy and various methods of chemical analysis, these samples can also act as control samples for the control analysis of the relevant elements separately. The series of reference materials have advantages of accurate value, good uniformity and precision and linear, more reasonable distribution of elements.
The Preparation Technology of Spherical Molybdenum Powder in Continous Induction Plasma
Authors: Huang Wei , Zhu Li Jun , Zou Min Ming , Shang Fu Jun , Su Ji Hong , Tian Xiao Yan , Zhang Tao
Published: July 2012

In this paper, the preparation technology of spherical molybdenum powder has been studied by using of continuous induction plasma powder synthesis system, and the flow-ability, particle size , the impurity content of powder before and after plasma treatment have been measured and compared. The result shows that, by applying for induction plasma preparation technology ,the powder’s flow-ability is improved, oxygen and carbon content is decreased markedly. the continuous induction plasma powder synthesis system shows high performance on particle size control.
Optical Dispersion Compensation for Optical Links Based on Nonlinear Optical Material
Authors: Yang Kang , Li Yan , Li Guo Yu , Chai Xing Quan
Published: July 2012

In order to compensate the dispersion in 40Gb/s optical links, the optical dispersion compensation is discussed because of its high compensation speed and small nonlinear. An optical equalizer, in post compensation, is presented and the results based on simulations show that an equalizer consisting of chirped fiber grating can mitigate dispersion effectively by setting the incident power from 6 to 8dBm.
Effect of Intercritical Annealing Temperature on Martensite Amount for Dual-Phases Steel
Authors: Fang Fang , Yin Yun Yang , Wang Hui , Lin Cheng Jiang
Published: July 2012

The theoretical prediction of intercritical annealing temperature for DP steels was conducted by thermodynamic calculation, which agreed to the experimental results. When annealed at 800°Caccording to the calculated temperature of 807°C by setting ratios of α:γ in 70:30, the amount of martensite was 13~18% and the mechanical properties achieved DP590 grade. There was at least 10% to 12% austenite transformed to new ferrite and martensite between intercritical annealing and overaging procedure.
Effects of Heat Treatment on Microstructure and Mechanical Properties of Mg-3Sn-2Ca Magnesium Alloy
Authors: Yang Ming Bo , Guo Ting Zhang , Li Hui , Hu Hong Jun
Published: July 2012

The effects of heat treatment on the microstructure and mechanical properties of Mg-3Sn-2Ca alloy were investigated. The results indicate that after solutionized at 500 °C for more than 24 h, the morphology of the CaMgSn phase in the alloy changes from the continuous and/or quasi-continuous nets to the particle-like shape. Furthermore, after solutionized at 500 °C for 24 h, for a given aging temperature of 285 °C, with prolonging aging time the matrix hardness of the alloy increases, and attains the maximum at 32 h of aging time and beyond that it decreases. In addition, it is preliminarily inferred that heat treatment would give a beneficial effects on the tensile and creep properties of Mg-3Sn-2Ca alloy due to the modification of the CaMgSn phase.
Microstructure Variation in the Arc-Melted Cr-Cr2Nb Hypereutectic Alloy
Authors: Li Ke Wei , Li Shuang Ming , Xue Yun Long , Fu Heng Zhi
Published: July 2012

Microstructure of the arc-melted Cr-20at%Nb alloy solidified in different positions was investigated using optical microscope (OM) and scanning electron microscope (SEM). The results show that fully coupled eutectic was developed at the bottom of the ingot and then the eutectic experienced a columnar to equiaxed transition due to the decrease of G/V ratio (G the thermal gradient and V the solidification rate) with increasing the solidification distance. A novel lamellar structure was observed in the middle side of the arc-melted ingot, which may form by means of the eutectoid reaction of C14-Cr2Nb→C15-Cr2Nb+Crss. With the increase of the solidification distance from the middle side to the top side, the primary Cr2Nb phase underwent a nonfaceted to faceted transition.
Microstructure and Electrical Properties of Vanadium doped Bi4Ti3O12 Layer-Stuctured Ferroelectric Ceramics
Authors: Wu Yun Yi , Wang Lei , Hua Zhi Qiang , Li Tao
Published: July 2012

A series of ferroelectric BIT ceramics with various V2O5dopants were prepared by conventional solid-state route. The influence of V2O5 dopant on microstructural and electrical properties of BIT ceramic were investigated in detail, which were examined by XRD, Raman spectra and P-E hysteresis loops, etc. X-ray Photoelectron Spectroscopy was used to examine the chemical state of the vanadium ions inside the BIT ceramics. Vanadium added to the BIT system can enhance the ferroelectric property due to the decrease of the concentration of space charge occurred during calcinations and weaken the polarization property due to the decrease of grain size and the change of chemical valence for vanadium ion. The BIT ceramic with 3 mol% V2O5dopant exhibits a remnant polarization 2Pr of 25.6 μC/cm2, and coercive field Ec of 47.4 KV/cm. Besides, the conductivity of BTV was obviously lower than that of the undoped BIT, which was accord with donor dopants decreasing the conductivity of a material with a p-type mechanism.
The Effect of Substituting of Al on the Curie Temprature and Magneto-Resistance of Double Perovskite Compounds
Authors: Li Xiang Hu , Li Dan
Published: July 2012

The compounds of Fe substitution of Al in nanotructured Sr2Fe1-xAlxMoO6(0≤x≤0.2) double perovskite have been prepared by sol-gel method. The x-ray diffraction patterns of the samples show that the samples are in nanometer range. The Curie temperature and thesaturation magnetization of the samples decrease with the increasing of Al substitution. And the magnetoresistance of the samples increase with the increasing of x.
Atomic Scale Kinetic Monte Carlo (KMC) Simulation on a New {111}-Oriented Chemical Vapor Deposition (CVD) Diamond Film Growth Process: Two-Step Growth
Authors: Zhang Li Zhu , Wang Fu Zhong
Published: July 2012

The growth of {111}-oriented CVD diamond film under a two-step model was simulated at atomic scale by using revised KMC method. The simulation was conducted at various substrate temperature (1100K-1400K), CH3 radical concentration (0.01%-0.03%) and atomic hydrogen concentration (0.005%-0.3%). The results showed that: Substrate temperature (Ts), the concentration of CH3 ([CH3]) and the concentration of atomic H ([H]) can produce important effects on the film deposition rate and surface roughness.
Simulation and Optimization on the Process of Acetic Acid Dehydration via Extraction Combined with Azeotropic Distillation
Authors: Chen Yi Feng , Yang Ji He
Published: July 2012

Some azeotropic entrainers in the process of acetic acid dehydration could extract acetic acid from its dilute solution; this text would observe the ability of extraction about these entrainers mentioned in the literatures. By using the EXTRACT module in Aspen Plus, it is found that isopropyl acetate was the most effective extracting agent. The process of acetic acid dehydration via extraction combined with azeotropic distillation by using isopropyl acetate was established. Acetic acid was first extracted from its dilute solution and then was distilled in the azeotropic column, finally acetic acid having 99.8%(weight percent) purity was obtained. This process avoided evaporating a lot of water from the solution, and the entrainer’s existence effectively enhanced the relative volatility between acetic acid and water. The simulation result indicated that when dealing with the acetic acid solution used in this research, the total heat exhaustion was reduced from 11.73MW to 2.98MW and the number of theoretical plates needed in the distillation was also reduced from 65 to 34 compared with simple distillation.
Research on Mechanical Performance Analysis and Structural Modification of Longitudinal Thrust Rod
Authors: Zhou Chang Feng , Zhao Gui Qing , Zhang Heng Hai , Chen Xiao Kang
Published: July 2012

To research the mechanical performance and vibration modes of current longitudinal thrust rod of rear axle, the finite element model of original thrust rod is established and analyzed with NASTRAN codes. The simulation results demonstrate: the maximum stress of original thrust rod of dump truck is in the limit of the yield strength of material, which satisfies with the design requirements; the first step modal frequency of the component under free conditions is greater than upper limits value of the excited frequency of roads, which can evade the resonance excited by irregular roads. But there is structural stress concentration area in the thrust rod, so the structure of thrust rod is modified to ameliorate the stress state of this area. The maximum structural stress is reduced by 35.1% on the basis of reduction by 4.7% in total weight, which indicates the modification improves the mechanical and modal performance greatly. The research above has significant reference values for mechanical performance analysis and lightweight design of complicated automotive components.
Numerical Study of Plastic Strains on Slope Instability
Authors: Wang Mao Hu , Xu Zhen Liang
Published: July 2012

This article simulates an open pit slope stability using the ANSYS software, which is based on the finite element strength reduction theory, three kinds of slope instability criterion of the strength reduction method are applied to judge whether the slope is on the limit equilibrium state, the incremental search method is used to search the safety factor of the slope stability, and the results show that, the slope body damages when the plastic zone developed from the top to the bottom, in the numerical simulation the finite element iteration calculation didn’t just converge, the corresponding former level of reduction factor is the safety factor, This article can have a guiding significance on the safety production of the open-pit mine.
Thin-Film Residual Stress Detection Method Based on Flexible Hinges
Authors: Wang Hai , Tong Yun Hua
Published: July 2012

The residual stress introduced in the thin-film process may caused some problems, especially after removing of the sacrificial layers below, the suspended structure may be bended due to the release. In this articles we will develop a new in-situ residual stress detection method based on flexible hinges for thin-film materials, then described the detection principle theoretically and simulated its properties by FEA method.
Residual Stress Formation at Arbitrary Types of Rollers during the Running in Process
Authors: Muraviev O.P. , Sikhimbayev M.R. , Absadykov B.N. , Arymbekov B.S. , Tkacheva Y.O.
Published: July 2012

In the article the results of the design and analysis of mathematical model for determining residual stresses in the surface of layer at parts processed by plastic surface deformation (PSD) in which the rollers having an arbitrary shape and size. It is shown that for the calculation of stresses in the surface of layer it should not be defined by them at a forcing point but by a function of contact stresses. Integral equations are obtained for calculating the stresses in the body parts at the processing of PSD rolls of arbitrary size and shape of the stress distribution over the contact area. We found that the tangential and radial residual stresses depend on the magnitude of the force F and its distance from the point at which the voltage is considered in detail. There is a sharp decrease in the influence of forces on the stress in the surface of the part of the distance to the point in question.The calculated data generated by the proposed method are highly matches with data during the experimental investigations. Maximum deviations of the calculated values do not exceed the errors of the experiments and adequate treatment of each other at a significance level of 0.05.
Prediction of Limiting Strains for Square Pattern – Square Hole Perforated Commercial Pure Aluminium Sheets
Authors: Venkatachalam G. , Narayanan S. , Sathiya Narayanan C.
Published: July 2012

Forming limit diagram (FLD) is the most appropriate tool used to obtain the safe strain region in sheet metal forming industries. This FLD is based on limiting values of major and minor strains. This Limiting strain is the strain at the onset of fracture / necking in a sheet metal. It is influenced by the material / condition of the material, strain condition in geometrical features of a sheet metal. In this paper, square pattern – square holed, perforated commercial aluminium sheets are considered for the study. The limiting strain for the above perforated sheet metals is predicted using finite element analysis. It is found that the limiting strain is controlled by percentage of open area, ligament ratio and hole size.
Investigation into Effect of Tool Wear on Drilling Force and Surface Finish While Dry Drilling Aluminum 2024
Authors: Ashrafi Sina Alizadeh , Davoudinejad Ali , Barzani Mohsen Marani , Salehi Pouria
Published: July 2012

Dry drilling of aluminum is environmentally friendly machining technique; in the meanwhile it is difficult to carry out due to aluminums gummy behavior and its tendency to adhere to cutting tools which diminishes hole quality. In spite of recent developments in cutting tool technology, HSS tools are still a cost effective choice due to relatively high toughness and feasibility to manufacture complex geometries of HSS drills besides its low price, make this tool a common choice for drilling soft materials such as aluminum. In this study effect of tool wear on thrust force and torque analyzed and hole quality assessed with respect to tool wear along tool life. Dry drilling on aluminum 2024, performed using HSS and HSCo drills at constant feed rate of 0.04 mm/rev and two cutting speeds of 28 and 94 m/min. Results revealed that the abrasive wear on flank face and BUE on chisel edge, margin and cutting lips were dominant mechanisms in all drills. It was found that with propagating the wear land on tool, thrust force and torque increased in both tools.
Deformation and Stress Analsys of Wrapped pin Joint between Composite and Metal
Authors: Sun Jiang , Xiao Qi
Published: July 2012

By filament winding technology, a pin hole can be formed in the process of composite manufacturing through wrapped fiber tow around pin, so fiber tows around the pin hole are continued. The paper presents the deformation and stress analysis for this kind of pin hole and compares those with ordinary pin hole. The numerical results show that the wrapped pin hole has a good stress and deformation ability.
Influence of Die Profiles and Cracks on Joint Buttons on the Joint Quality and Mechanical Strengths of High Strength Aluminium Alloy Joint
Authors: Li De Zhi , Han Li , Lu Zong Jin , Thornton Martin , Shergold Mike
Published: July 2012

Currently, self-piercing riveting (SPR) is a major technology used by manufacturers to join aluminium body structures to reduce vehicle weight. Normally, for SPR of one specific stack more than one die, rivet, and velocity combination can be applied. Which parameter combination is chosen is depending on the surrounding joints. In order to increase productivity and reduce the number of robots used, it is preferred to use the same rivet/die combination for as many joints as possible. This means for the same stack, different die may be used. To see the influence of die profiles on joint quality, a DF die, which would generate severe cracks and a DC die, which would generate no cracks or only small cracks, were used to join two stacks with a high strength aluminium alloy, AA6008T61, as the bottom layer. The joint quality was analyzed, and the static and fatigue strengths of these stacks were studied. Results showed that cracks on joint buttons might reduce static and fatigue lap shear strength but had no obvious influence on static and fatigue T peel strength for the joints studied.
FE Based Thermal Analysis of Void Effect in IGBT Mechanical Module
Authors: Fang Xin Yu , Zhang Xiao Ling , Gong Wei Hua , Zhang Jian
Published: July 2012

In this paper, a reasonable model under the thermal void effect of the Insulate Gate Bipolar Transistor is been built. Finite element analysis (FE) is introduced to analyze thermal characteristics of the model. The results indicate that the heat distribution of IGBT is determined of voids with different sizes, positions and the intensity. Besides, the synergy of void effect and heat coupling effect would significantly increase the temperature of the chip.
Curing Behavior on Kaolin-Based Geopolymers
Authors: Heah C.Y. , Kamarudin H. , Al Bakri A.M. Mustafa , Binhussain M. , Musa Luqman , Khairul Nizar I. , Ghazali Che Mohd Ruzaidi , Liew Y.M.
Published: July 2012

This paper aims at investigating the influence of curing process on kaolin-based geopolymers. Kaolin-based geopolymers were prepared by the alkali-activation of kaolin with alkali activating solution (mixture of NaOH and Na2SiO3 solutions). The compressive testing, XRD and FTIR analysis were performed. The compressive strength results showed that curing at 60°C for 3 day achieves better strength. XRD analysis revealed that the entire geopolymer sample reduced in intensities and became amorphous at longer age while FTIR analysis indicated the presence of geopolymer bondings. Both analyses showed the presence of large amount of un-reacted remained in the system were the reason of the low compressive strength obtained.
Meshless - The Finite Element of a Direct Coupling Method Mechanical Problems in the Application
Authors: Wang Jin Ping , Gao Yu Jing , Wang De Hua
Published: July 2012

Coupling method is developed in recent years to solve numerical problems a new method, meshless - the finite element of a direct coupling method is based on the definition of the generalized unit of coupling of the new method . The core of this method is the use of each unit in the shape function to the assumption that the brain that the whole sub-domain to be seeking to solve the unknown field function. Coupling with other compared with the method is simple to calculate the advantages of a short time.
Fuzzy Control of the 35t/h Chain Boiler with Regulable Rules
Authors: Wang Feng
Published: July 2012

The 35t/h boiler used in the Thermal Power Plant of Tangshan Iron and Steel Co. Ltd. is a chain furnace. Its control system of the conmbustion process is a 2 input-2 output system whose inputs are the quantity of the fuel and desuperheater spray, outputs are the steam pressure and the steam temperature. Due to the nonlinearity, large lag, and coupling impact between the input and output parameters, fuzzy control was introduced. The fuzzy control rule has the adjustable factors and is described by the analytic relationships. The steam pressure is a 2-level control, including the original and final control. In the final control, the effect of the fuel quantity change on the steam temperature is taken into consideration. Thus the correction of the steam temperature for the fuel quantity is introduced. The control rule can be adjusted on-line owing to the regulable factors. For the reason, the control is closer to the actual production, which makes the production more smooth and reliable. Lastly, the modular structural design by means of PLC makes the realization of the fuzzy control algorithm more convenient.