bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of 1-MCP and CaCl2 on Quality of Chinese Jujube Stored at Low Temperature
Authors: Li Xi Hong , Zhang Li , Wang Xiu Li , Li Yuan Yuan
Published: November 2010

Chinese jujube (Zizyphus jujuba M) fruit at the postharvest stage was easily have a dramatic decline in quality. The effect of 1-MCP and CaCl2 in delaying fruit ripening and improving storage quality was investigated through this study. Chinese jujube fruit were harvested and then treated with 1µL L-1 1-MCP for 24 h at 20°C, immersed in 1% CaCl2 solution for 10min and their combination, then kept 0 °C and 80–90% RH after treatment. Results indicated that 1-MCP and CaCl2 were effective in terms of senescence inhibition during storage and compared to control, and the performance of 1-MCP was little better. Fruit treated with 1-MCP and CaCl2 had ability to maintain firmness, soluble solid concentration (SSC), weightlessness, membrane permeability. The ethylene production rates of jujube fruit were effected signiﬁcantly by treatment with 1-MCP, not affected by CaCl2 treatment like control samples, however, they both had a visible influence on the content of MDA compared fruit with untreated. Furthermore, treatment with 1-MCP + CaCl2 resulted in additive beneﬁcial effects on ripening inhibition of the fruit and maintaining the qulity of Chinese jujube fruit.
BOM Configuration Based on Genetic Algorithm
Authors: Zeng Fu Hong , Zhou Lan Hua
Published: November 2010

In order to meet the requirements of product design and find suitable combination of within a short time, the concept of Knowledge-body based on BOM (KBOM) was put forward, which consisted of basic entities that could support all activities throughout product lifecycle with less redundancy, and all the product data throughout product lifecycle was associated with the core of KBOM directly or indirectly. A reusable and sharable configuration model of product was established to represent domain-specific knowledge based on KBOM. Genetic algorithm was used to solve the issue concerned with BOM configuration in a short time with value coefficient, quality level and reliability as evaluation parameters. Finally, as a case study, the display module of a notebook was analyzed. The results indicate that the evaluation can be effectively applied in a large-scale BOM configuration.
Fracture Property of Mass Concrete with Inclusion of Fibers
Authors: Yang Hua Quan , Chen Xia , Dong Yun
Published: November 2010

In order to obtain the effect of fibers on fractural property of mass concrete, it had investigated physical performance, elastic modulus and bending toughness of mass concrete with the presence of steel fiber and polypropylene fiber(PPF). Results showed that the inclusion of PPF caused a slight decrease in initial cracking strength, flexural strength and elastic modulus, yet resulted in small increase in equivalent flexural strength, capacity-carrying loading variation coefficient and toughness.The presence of steel fiber was of significance to increase initial-cracking strength, flexural strength and equivalent flexural strength, and produced a slight increase in elastic modulus and significant improvement in capacity-carrying variation coeffecient and flexural toughness. Overall, the inclusion of steel fiber is rated better than PPF in improving ductility and crack resistance of concrete.
Multipoint Rapid Metal Forming Technology Based on Micro-Fluid Control
Authors: Zeng Guo Ying , Zhao Deng Feng
Published: November 2010

Based on micro-fluid control, a rapid metal forming method with high efficiency is proposed. At first, the basic principal is introduced. The metal liquid flows out of a large number of micro-pores, and the multipoint parallel crystallization is thus realized. During the forming process, the open or close of micro-pores is controlled by surface tension to obtain required shape of part. Then the technological parameters are deduced. Preliminary experiment shows that rapid open and close of micro-pore can be realized acted on surface tension. This method has the basic characteristics of rapid prototyping technology and continuous casting technology, which can overcome the shortcomings of inefficient and difficulty to create high melting point metal parts for current rapid prototyping.
Lagrangian Relaxation for Multiprocessor Task Scheduling Problem with Variable Job Profiles
Authors: Han Xiao Le , Lu Zhi Qiang , Xi Li Feng
Published: November 2010

In this paper the multiprocessor task scheduling problem with variable job profile is addressed. Such problem originates from many practical resource assignment contexts. Based on discretized parameters, the problem is formulated as an integer programming model. Due to the complexity of the problem, a Lagrangian relaxation is applied to solve the problem. The numerical experiment demonstrates the effectiveness of our algorithm procedure.
Preparation of an Iron Oxide Modified Montmorillonite for Removal of Arsenic in Waters
Authors: Liu Hai Fei , Miao De Ren , Liu Fei
Published: November 2010

Most concerns have focused on the arsenic (As) contamination in wastewater. Montmorillonite (MMT) has been proved to be a good adsorbent for removal heavy metals existing as cation in ground water while it is invalid for anions. However, arsenic usually exists as anions in aqueous. Accordingly, suitable modifications on MMT need to be done before using. This paper presents the results that a kind of commercial MMT has been modified by iron oxides under normal and inverse titration conditions. The x-ray diffraction (XRD), Thermal Gravimetry Analysis and Differential Thermal Analysis (TGA-DTA) and SBET analysis have been employed to elucidate the modification mechanisms. Modification characteristic analysis illustrated that the iron oxide associated with MMT by coated style as polymerization of hydroxyl-Fe (Fe (OH) 3) under inverse titration condition. Under normal titration condition, on the other hand, the iron oxide associated with MMT predominant by intercalation as goethite (FeOOH). The arsenic removal efficiencies of different modified products for polluted water have also been verified by batch experiments. Results proved that Iron oxide modified MMT on the removal efficiency of arsenic significantly increased and the normal titration is better than inverse titration as indicated by the arsenic removal ratios under the same experimental conditions. Based on these results, the iron oxide modified MMT by normal titration procedure is a promising material for removal arsenic in wastewaters.
Effect of pH, ORP and Influent COD on Hydrogen Content in Fermentative Hydrogen Production
Authors: Zhu Lei Lei , Wang Bing , Gao Shuang , Yao Xin , Cao Li , Bai Xu Feng , Li Yong Feng
Published: November 2010

Fermentative hydrogen production was carried out using a continuous flow stirred tank reactor (CSTR) for the investigation of the hydrogen content in the biogas. Molasses was used as the substrate; hydraulic retention time (HRT) was 6 h; the temperature was in the range of 35±1 .It was showed that hydrogen content increased from 38% to 59% when pH decreased from 5 to 4.6 with oxidation-reduction potential (ORP) increased from -420 mV to -380 mV. The hydrogen content dropped from 50% to 30% as influent COD was improved from4000 mg/L to 6000 mg/L. Hydrogen content increased to 35% when influent COD was improved to 7000 mg/L, however decreased to 25% when influent COD was 8000 mg/L. Ethanol in terminal products is accompanied with hydrogen production but with lower hydrogen content. Butyric acid indicates higher hydrogen content than ethanol.
Numerical Simulation for Magnetic Fluid Inclination Sensor
Authors: Sun Ming Li , Cui Hai Rong , Wang Bin , Chen Wei Zeng
Published: November 2010

Based on the finite element software ANSYS, the magnetic-circuit field of sensor is analyzed. The results of numerical simulation show that output voltage of sensor and inclination angles are linear dependence. The factors affecting the sensor sensitivity are inspected, which include the exciting signal frequency, the peak voltage and the susceptibility of magnetic fluid.
Research on Thick-Wall Columnar Pressure Vessel with Auto-Frettage
Authors: Cao Qing Hua
Published: November 2010

The theoretic formula for the optimal radius of elastic-plastic junction in auto-frettage thick-wall columnar pressure vessel was deduced. on the basis of the twin shear strength theory, the relationship between the allowable maximal operating pressure for the pressure vessel and yield was analyzed,Bauschinger effect to reverse yield with auto-engaged vessel was investigated, The procedure was illustrated with the help of numerical example and the results show the reliability of the designing method.
Medium Characteristics on Selective Grinding of Low Grade Bauxite
Authors: Zhu Yi Min , Han Yue Xin , Tian Yi Lan , Hong Wang Ze
Published: November 2010

Selective grinding of bauxite with ratio of Al2O3/SiO2(A/S) 4.4 at ball mill were studied in order to investigate the effect of grinding media characteristics on selective grinding of bauxite. Results show that when diameter of ball media is Φ15mm, selective grinding effect is best and at this moment A/S of the product at -0.5+0.28mm granularity is up to 7.5. Ball/powder weight ratio, charge rate, and size composition of grinding media have little influences on particle size composition of powder product, but have great influences on the A/S at different granularity powder product. At condition of size composition of grinding media Φ30mm:Φ20mm:Φ15mm＝20%:50%:30% and charge rate 40%, the grinding results are best and at the moment ωAl2O3/SiO2 is up to 7.5, yield 27%, and Al2O3 recovery 30%.
Characterization of the Alkyl-Ammonium Adsorption Amount in Organomontmorillonite and its Effect on the Viscosity of Organomontmorillonite Gel
Authors: Liu Yu Qin , Lu Xian Jun , Qiu Jun
Published: November 2010

The structure and thermal property of organomontmorillonite (OM) were studied by X-ray diffraction (XRD), differential thermal analysis (DTA), and thermalgravimetric analysis (TGA).Based on the thermal property of OM, a new method for quantitative characterization of the alkyl-ammonium adsorbed in the layers was established, and the influence of adsorption amount on the viscosity of OM gel was examined. Changes in the basal spacing of OMs and Na-montmorillonite (Na-mont) indicated that alky-ammonium ions intercalated into the montmorillonite layers. TGA results showed that OM and Na-mont had different thermal property, Na-mont held more free water in the layers. The intercalated alkyl-ammonium in OMs decomposed at the temperature of 230~480°C. Effective dosage (DOSeffective) has significant influence on the viscosity of OM gel. Under the optimal DOSeffective(1.1~1.3CEC), the alkyl-ammonium cations can fully cover the exchangeable site in the layers, then the “card-house” structure formed. Structure of the alkyl-ammonium cations determines the intercalation efficiency, the longer the carbon chain, the higher the intercalation efficiency. The intercalation efficiency has no evident correlativity with the viscosity; however, structure of the alkyl-ammonium cations determines their arrangement in the layers.
Interfacial Coordination and Nanofiber Fabrication of a Tri-Pyridine-Based Derivative with Platinum (II) Ions
Authors: Jiao Ti Feng , Xing Yuan Yuan , Zhou Jing Xin
Published: November 2010

In order to investigate the supramolecular assembly and in situ coordination of special amphiphiles with aromatic moieties and without long alkyl chain, a tri-pyridine-based derivative was designed and synthesized. The spreading behaviors of the Langmuir films fabricated from pure water and the subphase containing K2PtCl4 were studied in details. It was found that the compound could form interesting Langmuir films through the interfacial coordination with Pt(II) ions. While well-dispersed nano particles were observed for the films transferred from pure water surface, dense coiled nanofibers could be obtained from Pt(II) subphase, which could be ascribed to the matching direction of coordination and - stacking of aromatic moieties. The transferred LB films were characterized by a series of methods. A rational packing mode was proposed.
Vulcanization Kinetics of Natural Rubber Coagulated by Microorganisms with Use of a Vulcameter
Authors: Wang Zhi Feng , Li Si Dong , She Xiao Dong
Published: November 2010

Kinetics of vulcanization of natural rubber coagulated by microorganisms (NR-m) was studied with the use of a vulcameter. In the induction period of vulcanization, the time t0 of NR-m is shorter than that of natural rubber coagulated by acid (NR-a), and the rate constant k1/a of NR-m are greater than that of NR-a. Both the curing periods of NR-m and NR-a consist of two stages. The first stage follows first-order reaction. The rate constants k2 of NR-m in the first stage are greater than that of NR-a at the same temperature, and so are the activation energy E2. The second stage (end stage of the curing period) does not follow first-order reaction, and the calculated reaction order n of NR-m is in the range of 0.82-0.85, and that of NR-a is in the range of 0.64-0.72. The rate constants k3 of the second stage for NR -m are greater than that of NR-a at the same temperature, and so is the activation energy E3.
Investigation on Ultimate Bearing Capacity of Recycled Aggregate Concrete-Filled Steel Tubular Short Columns under Axial Compressive Load
Authors: Zhang Zhao Qiang , Xiao Shu Lian , Lei Jin Song
Published: November 2010

Based on the Unified Strength Theory(UST),the ultimate load calculation formula for the recycled aggregate concrete-filled steel tubular short columns is derived in this paper,in which the decrease of longitudinal stress because of the hoop tensile tension is considered. The influence of intermediate principal stress on the ultimate load is studied and the failure mechanism is also discussed. The results show that the intermediate principal stress have important effect on the ultimate load which increases with the strength parameter .Through the comparison between the experimental results and the calculating results obtained in this paper,the deviation is small,and it shows that the formula have significance in exerting material potential.
Synthesis and Characterization of Nano Hydroxylapatite by Reaction Precipitation in Impinging Streams
Authors: Yuan Jun , Wu Yuan , Zheng Qi Xin , Xie Xiao Lin
Published: November 2010

Hydroxylapatite(HAP) nano-whiskers are prepared by reaction-precipitation in the submerged circulative impinging stream reactor(SCISR), with (NH4)2HPO4 and Ca(NO3)2 as the reagents; and the products are characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The results TEM measured indicate that the product prepared under typical operation conditions is average-sized 15nm and 50-70nm long. Multiply repeated experiments illustrates that, because of the excellent performance of the reactor, the preparation process can be easily controlled to yield nano rod/whisker hydroxylapatite with very narrow size distribution.
Influence of Chemical Modification on the Electrical Properties of Si Nanowire Arrays
Authors: Li Chuan Bo , Fobelets Kristel , Syed Jalal S.N. , Ng Wei A. , Durrani Zahid A.K.
Published: November 2010

The influence of the chemical modification on the electrical property of Si nanowire array was studied. It is found that H-terminated Si nanowire has a better electrical conductivity while OH-passivation could increase their resistance. It is believed that the introducing of OH group on the surface nanowire increases the interface traps and it is confirmed by our 1/f noise measurement.
Preparation of Silica Nanoparticles Using Silica-Rich Filtrate from Potassium-Rich Rock
Authors: Yin Cong Cong , Qi Hong Bin , Chen Xiao Chao , Wang Zhi Hui
Published: November 2010

The silicon-rich filtrate which was obtained from the desilication solution of potassium-rich rock was used as raw materials to prepare nanometer sillica and ultrasonic dispersion method was applied to the chemical precipitation process. A detailed study was carried out on the effect of filtrate concentration, surfactant dosage, reaction temperature, calcinations temperature, ultrasonic dispersion on size of silica nanoparticles. The basic properties and size of particles were characterized by means of FE-SEM, TEM, XRD, TGA and FTIR. The results obtained in the study indicated that monodisperse and uniform-size silica nanoparticles were prepared using ultrasonication by chemical precipitation process and the average particle size was 50 nm.
Numerical Simulation of Laser Thermal Stress Forming of Thin Steel Sheet
Authors: Tao Mao Ke , Shen Zong Bao , Zhang Cheng , Wang Kai
Published: November 2010

Laser thermal stress forming is a flexible forming process that forms sheet metal by means of stresses induced by external heat instead of by means of external force. Based on the analyzing of the influence of temperature on the thermal and mechanical properties of the materials, a 3D thermal-mechanical coupling model of laser thermal stress forming of thin steel sheet is set up in this paper. Based on ANSYS APDL developing platform, the stress field, temperature field and deformation field are obtained by numerical simulation of laser scanning of Q235 mild steel sheet for one time. Moreover, the forming progress and mechanism have been analyzed. The results show that the laser thermal stress forming is a quasi-steady-state process and its forming mechanism belongs to temperature gradient mechanism.
Carbon Fiber Cloth in Structural Engineering Application
Authors: Han Jian Qiang , Fu Xiu Yan , Zhang Yu Min
Published: November 2010

The frame beam end uses the carbon fiber cloth restraint, then uses the steel stranded wire assembly,which is a new assembly architecture structure. This thesis studies deeply the crack development characteristics, failure pattern, hysteresis curve and the displacement ductility of prestressed precast reinforced concrete frame, by analyzing one prestressed precast reinforced concrete frame under low reversed cyclic load test. We build a model using finite element analysis software to the test piece model analysis, the analysis result agree well with the experimental results. Experimental studies indicate that assembly of prestressed reinforced concrete frame structure has a good seismic performance. This prestressed precast reinforced concrete frame is a new kind of structural system complying with the development of architectural industrialization, which is worthy of popularization and application in the earthquake area.
Electrochemical Characteristic of Cr-Based Film Coated 304SS as PEMFC Bipolar Plates
Authors: Huang Nai Bao , Liang Cheng Hao , Lin Guo Qiang , Xu Li Shuang , Li Bao Lian
Published: November 2010

By using electrochemical techniques, the electrochemical characteristic of Cr-based film coated 304 stainless steel (304SS) as proton exchange membrane fuel cell (PEMFC) bipolar plates, which was deposited by cathodic arc deposition technology, was studied. The results indicated that Cr, CrN, (TiCr)N and (TiN+Ti) film could not only decreased the steel’s contact resistance but also improved its corrosion resistance and the fuel cell stack’s performance. Since Cr, (CrN) and (TiCrN) film were more compact than (TiN+Ti) film, which contained the oxides of Ti, as bipolar plates, the performance for all film change in the following order: Cr film ≈(CrN) film ≈ (TiCrN) film >(TiN+Ti) film.
Effect of Hydrogenation on Structural, Optical and Electrical Properties of Amorphous InAsSb Thin Films
Authors: Yao Yan Ping , Liu Chun Ling , Qi Hai Dong , Chang Xi , Wang Chun Wu
Published: November 2010

Amorphous InAsSb films and hydrogenated InAsSb films are deposited on substrates of quartz glass and silicon by rf magnetron sputtering technique in different gas ambient. The effect of H addition on structure, optical properties and electrical properties of a-InAsSb is studied. It is found that the bonded hydrogen content increases with increasing H2 to Ar flow rate radio(R). When R is 0.1, Hydrogen addition shifts the optical absorption edge to higher energy, decreases the dark conductivity and improves the photo-sensitivity. However, hydrogen addition produces the crystallization of the film at R>0.1. Moreover the optical gap, dark conductivity and photo-sensitivity of the films have a reverse change compared with that in R=0. These results demonstrate that hydrogen has obvious passivation effects on rf sputtered amorphous InAsSb thin films only at R=0.1.
Numerical Simulation of Fiuid Field of Molten Steel in the Mold on 700mm×700mm Billet Continuous Caster
Authors: Bai Ming Hua , Tong Rui Song , Ge Jun Li
Published: November 2010

The fluid flow of Q235 molten steel in 700mm×700mm billet mold has been numerically simulated by a software FLUENT. By comparing the influence of submerged entry nozzle with different immersed depths, different number of holes and different opening angles on the distribution of fluid field, the structure of mold and the involved process parameters are optimized. With the application of the optimized structure and process parameters, the stability of fluid field is increased and the thickness uniformity of steel shell is improved, so that the quality of continuous casting billet is ameliorated, which provides a theoretical basis for engineering application.
Basic Properties of Woodceramics Made from Furane Resin/Bamboo Powder Composite
Authors: Zhou Wei Hong , Yu Yun Shui , Xiong Xue Liang
Published: November 2010

A new woodceramics was developed by furane resin and bamboo powder. Microstructures and phase identification of woodceramics were performed by scanning electron microscopy(SEM) and X-ray diffraction(XRD). The effect of content of furane resin on carbon yield ratio，dimension shrinkage，apparent density，comprehensive strength and volume electrical resistivity of woodceramics were investigated. The results show that the woodceramics is a kind of carbon/carbon composite composed by bamboo charcoal and glassy carbon, content of furane resin has a significant effect on the microstructure of woodceramics, but has a slight effect on the crystallinity of woodceramics. The carbon yield ratio, apparent density and comprehensive strength increase, and the dimension shrinkage and volume electrical resistivity decrease as the content of furane resin increases.
Physical and Electrochemical Properties of LiFePO4/C Cathode Material Prepared from a New Carbon Source
Authors: Yu Shi Xi , Luo Guo En , Luo Ying , Liu Wei , Yu Xiao Yuan
Published: November 2010

LiFePO4/C cathode materials for lithium ion battery were prepared by solid-state method from using Polystyrene (PS) micro-spheres as new carbon source. The structure, morphology and electrochemical performances of LiFePO4/C were investigated by X-ray diffraction (XRD), scanning electronic morphology (SEM) and galvanostatic charge-discharge tests and cycle voltammetry (CV). The results demonstrate that LiFePO4/C have single olivine type structure with small particle sizes. The electrochemical test results show that the residual carbon produced by the pyrolysis of PS microspheres with functionalized aromatic groups exhibites a better discharge capacity in the LiFePO4/C composite. The LiFePO4/C cathode material with 7 wt% PS delivers an initial discharge capacity of 141mAh/g at 0.1C and between 2.5-4.1V, and displays excellent capacity retention. The composite material exhibited a higher peak intensity and a smaller voltage difference between the oxidation and reduction peak, indicating a good electrochemical reaction reversibility.
Cutting Parameter Optimization for Multi-Pass Milling Operations by Genetic Algorithms
Authors: An Li Bao , Feng Li Jia , Lu Chun Guang
Published: November 2010

Parameter optimization in multi-pass cutting operations involves optimal selection of cutting speed, feed rate, depth of cut, and the number of passes, duo to significant influence of these parameters on the quality of machined parts and machining economics. In this paper, a non-linear mathematical model based on minimum production cost for multi-pass milling operations is presented. The unwanted material is removed by one finishing pass and one or multiple roughing passes depending on the total depth of cut. Various realistic constraints are considered when developing the model. Optimal values of machining parameters are found by Genetic Algorithms. An example is presented to illustrate the optimization model and solution approach. The method yields lower unit production costs compared with the results from the literature and machining data handbook.
Particle Tracking Computational Prediction of Hemolysis by Blade of Micro-Axial Blood Pump
Authors: Chen Xin , Tan Jian Ping , Yun Zhong
Published: November 2010

By analyzing fluid dynamics of blood in an artificial blood pump and simulating the flow field structure and the flow performance of blood, the blood flow and the damages in the designed blood pump would be better understood. This paper describes computational fluid dynamic (CFD) used in predicting numerically the hemolysis of blade in micro-axial blood pumps. A numerical hydrodynamical model, based on the Navier-Stokes equation, was used to obtain the flow in a micro-axial blood pump. A time-dependent stress acting on blood particle is solved in this paper to explore the blood flow and damages in the micro-axial blood pump. An initial attempt is also made to predict the blood damage from these simulations.
A New Building Energy-Saving Material of XH Self-Insulation Block
Authors: Wei Dai Xiao , Ma Li
Published: November 2010

This based on the analysis of the structure characteristics and thermal properties etc of the new XH self-insulation block as results that the application of new material has a positive effect in construction of energy-saving. Through the calculation verified the thermal performance of XH self-insulation block the heat transfer coefficient of subject site wall. The results showed that its full compliance with existing norms and standards on the thermal performance of external wall insulation requirements, meet the requirements of energy conservation. Compared with the traditional material XH self-insulation block have an obvious advantage in thermal insulation property, service life, economy and so on. Finally, use its application in the ladder classroom of Southwest University of Science and Technology for a description of the project application.
Static Finite Element Analysis of Container Flooring and Chassis Combinations
Authors: Wang Quan Zhong , He Chang Jiang , Xu Bin
Published: November 2010

We analyzed static finite element of the container flooring and chassis combination structure rolling by a car; then, we analyzed the maximum deformation and corresponding maximum stress of the flooring and chassis combination when chassis crossbeam cross-sectional shape from the U-shaped to the I-shaped and compared with the original structure with the same force, as well as the space between the central crossbeam decreased, we can see that, the appropriate crossbeam space can obviously increase the stiffness of the container and reduce the stress of the structure; at the same time, we analyzed the combinations which with different flooring structures, we can see that the difference deformation between the new combination and the original was small, so we know that the mechanical properties of flooring had little effect to the mechanical properties of the entire combination.
Mechanical Performance of Reactive Powder Concrete for Structure Engineering
Authors: Yan Zhi Gang , Zhong Tie Yi , An Ming Zhe , Ji Wen Yu
Published: November 2010

In order to study the mechanical performance of Reactive Powder Concrete (RPC) used for structure engineering, 38 series of RPC specimens are fabricated, cured, tested and analyzed. There are 5 sets of specimens are fabricated for each actual site structure engineering. The compressive strength, flexural strength and elastic modulus are tested according to the specimens and the compressive strength is tested with different age time. All the specimens are steam cured with the same situation as the structure. According to the test result, the compressive strength of RPC is up to 80MPa 3days after it is cast and the compressive strength is higher than 120MPa 15days later. The average flexural strength of RPC is 19.4MPa and the elastic modulus is 45.15GPa. The tested results show that the mechanical performance of RPC can satisfy the engineering requirement. The mixing proportion and the curing system can be used for engineering design and construction.
LiMn2O4 Powders Prepared by Solution Combustion Synthesis in Ethanol and Water Systems
Authors: Liu Gui Yang , Guo Jun Ming , Li Yan Nan , Wang Bao Sen
Published: November 2010

Spinel LiMn2O4 powders have been prepared at 500 for 5h by solution combustion synthesis in water or ethanol system, using lithium and manganese acetate as raw materials and no fuels. The structure and morphology of the products have been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The electrochemical performance has been charged or discharged in coin-type battery. XRD analysis indicates that the purity and crystallinity of the product prepared in ethanol are much better than these of the product prepared in water. SEM investigation indicates that the particles of the product prepared in ethanol are smaller and more dispersed than these of the products prepared in water. The product prepared in ethanol also exhibits better electrochemical performance than that of the product prepared in water. The initial discharge capacity of the product prepared in ethanol is 120mAh/g, and remains 110mAh/g after 20 cycles, at a current density of 50mA/g and in the voltage range of 3.2-4.35V.
Fabrication and Properties of Zinc Silicate Phosphors through Solid State Reaction
Authors: Jiang Guo Jian , Xu Jia Yue , Shen Hui , Zhang Yan , Xu Lin He , Zhuang Han Rui , Li Wen Lan
Published: November 2010

Zinc silicate-based (Zn2SiO4:Eu3+) long afterglow phosphors were produced by solid state reaction method. The effects of borax and Eu2O3 additive on the properties of fabricated products have been studied. The results show that, there is not much difference in phase compositions within the borax additive amount; however, their SEM morphologies are different. Borax additive can increase the grain size of the product. Some sintering phenomena could be observed in the sample with Eu2O3 addition. The fluorescence spectroscopy results indicate that, the emission peak of the sample with Eu3+ additive located at 612nm, which may be a good candidate for red phosphor applications. The luminescent mechanism of Zn2SiO4:Eu3+ is also discussed.
The Study on the Corrosion Resistance for Polyurethane Epoxy Resin Coating of AZ91D Magnesium Alloy
Authors: Lou Bai Yang , Dong Ling Yun , Li Xiao
Published: November 2010

Magnesium alloys are more and more researched and used as engineering materials in recent years. In the paper, the AZ91D casting magnesium alloy was as basic material by the proper chemical pre-treatment and then was coated with epoxy resin (EP) coatings modified with polyurethane (PU) for protection. The coatings’ adhesion strength, hardness, and corrosion resistance were studied by electronic universal tester, pencil scratch hardness tester, immersion test and electrochemical test. The effect of polyurethane addition on the properties of the coating was ales investigated. The results show that PU / EP ratio of 20% mass fraction can make the basic alloy good mechanical properties and excellent corrosion resistance. The interpenetrating network formed between the epoxy resin modified with polyurethane is of more excellent mechanical and corrosion resistance than pure epoxy resin to protect the magnesium alloy matrix.
Microstructure of Rapidly Solidified CuFe10 Alloys
Authors: Zhou Zhi Ming , Tang Li Wen , Liu Chun , Cao Min Min , Lei Bin Bin
Published: November 2010

Rapid solidification of CuFe10 alloys was carried out by melt spinning at three wheel speeds 4, 12 and 36 m/s. The microstructure and solidification behavior of the ribbons was investigated by scanning electron microscopy (SEM). The results showed that the ribbons generally have a microstructure consisting of a fine dispersion of a Fe-rich phase in a Cu-rich matrix, and that the morphology and size of the Fe-rich phase vary with the wheel speed. For lower wheel speeds, the Fe-rich phase shows dual morphologies, dendrites and spheroids. The Fe-rich spheroids show a wide distribution of size, and have a larger mean size on the free surface than on the wheel surface. Some Fe-rich dendrites are distributed around the Fe-rich spheroids, this means liquid phase separation occurred during rapid solidification. The Fe-rich phase shows one morphology-spheroids and the size of Fe-rich spheroids decreasing as the wheel speed increasing. The results were discussed with respect to the formation of the Fe-rich spheroids during rapid solidification. The microhardness of the ribbons increasing with the increasing of the wheel speed for the grain refining and the increasing of supersaturated solid solution.
Effect of Rare Earth on 30CrMnSi Steel Investment Castings Cracking
Authors: Tang Zheng Lian , Zhang Xin Ping
Published: November 2010

Through adding different amounts of rare earth into the crack sensitive 30CrMnSi steel samples used in investment casting, the cracking tendency of the steel was evaluated and the optimum amount of rare earth addition was obtained. The results show that the cracking susceptibility decreases with the increase of the amount of rare earth added. The cracking susceptibility was lowest at the addition amount of rare earth ferrosilicon alloy being 450g per 50kg of 30CrMnSi steel, while increasing again thereafter with the addition amount up to 600g. It was revealed that the addition of rare earth with an appropriate amount can refine grains, reduce sulfur content, change the volume fraction and size of inclusions as well as improve their distribution, reduce or eliminate ferrite network in castings, and improve the hardness of the matrix, thus finally reduce the cracking susceptibility of the steel.
Study on Current Imaging of Nugget in RSW Based on Magnetic Field
Authors: Li Yang , Luo Zhen , Fan Nai Feng , Xuan Wen Bo
Published: November 2010

Since the nucleation of resistance spot welding is a close and invisible process, it is difficult to monitor its nucleation quality reliably. In order to estimate the quality of weld spot, this paper uses magnetic flux density around the nugget to reconstruct the current distribution in the faying surface between two workpiece. In the study, we found the inverse model of welding current and its magnetic flux density around the nugget. Since the model had ill-posedness, the regularization method was required to solve the problem. Conjugate Gradient Method was used to reconstruct the current distribution. The result shows that the image can reflect the main characteristic of current distribution, and it can be used for estimate the quality of weld spot.
Design of Dog-Bone-Shaped Ultrasonic Vibrational Fatigue Specimen and its Application in Study on VHCF Behavior of 6063 Aluminium Alloy
Authors: Liu Yong Jie , Chen Sha Gu , Tian Ren Hui , Wang Qing Yuan
Published: November 2010

Based on the design of specimen with standard hourglass shape, a modified dog-bone-shaped ultrasonic vibrational fatigue specimen was proposed and studied in this paper. The resonance length and the distribution functions of axial displacement and stress of such specimen were obtained analytically. A comparison of the very high cycle fatigue (VHCF) life of 6061 aluminium alloy with dog-bone-shaped specimen and hourglass-shaped specimen was done and it indicate that the forer is obviously lower than the latter and the data obtained by specimen with proposed shape are conservative. Then, the ultrasonic vibrational fatigue test of 6063 aluminium alloy specimen with dog-bone-shape was done, showing that the fatigue failure occured at the middle of the specimen with invariable section where has predicted maximum stress; the S-N curve descends continuously and there is no fatigue limit as the traditional fatigue conception describes; the fatigue crack grows in the form of shearing.
Natural Vibration Analysis of Composite Laminates with Non-Penetrating Damage Repaired by Two Kinds of Bonding Methods
Authors: Liu Feng , Zhang Zhong Bo , Yan Jun
Published: November 2010

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the natural vibration of the square composite laminates with clamped edges is analyzed. The natural vibration frequencies and modes of laminates without damage are given based on finite element method. The three dimensional finite element models of the same square laminates with non-penetrating damage repaired by two kinds of bonding methods are built. The natural vibration frequencies and modes are also given. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the natural vibration frequencies of the composite laminates all increase after it is repaired either by scarf bonding method or scarf and surface bonding method. After scarf bonding repairing, the lowest natural frequency increases about 3.6% and the second natural frequency increases 3.7%. After scarf and surface bonding repairing, the lowest natural frequency increases about 4.5% and the second frequency increases about 6.4%. The natural vibration modes of different repairing models are similar. The increase of natural frequencies may cause temporary vibration of aircraft skin made of composite laminates. The risk of resonance caused by bonding repairing is small.
Effects of Cooling Rate on Quasicrystal Microstructures of Mg-Zn-Y Alloys
Authors: Wang Yue Mei , Wang Zhi Feng , Zhao Wei Min , Cui Yan , Yang Jie , Zhao Rui , Hur Bo Young
Published: November 2010

Mg72.5Zn26Y1.5 quasicrystal alloys were investigated under different solidification conditions. The specimens of Mg-Zn-Y alloys with cooling rates from 13.2K/s to 69.8K/s were gathered by a designed multi-channel temperature acquiring system and then the microstructures and phase evolution of the alloys were analyzed. The results show that the precipitation temperature of icosahedral quasicrystal phase (I-phase) increased with cooling rate increased from 13.2 K/s to 69.8K/s. The microstructure was mainly made up of α-Mg, I-phase and Mg7Zn3 phase. Meanwhile, the quasi-crystalline morphology was significantly different in the experiments. It changed from five (six) petals to the big pentagon with the decreased cooling rate.
Experimental Study on the Bending Properties of GFRP Middle Beam in Foundation Pit Support
Authors: Zhang Wei , Zhang Ming Yi , Gao Li Tang
Published: November 2010

The laboratory studies on the mechanical properties of the GFRP beams with two different sections are carried out. Their mechanical behavior and the failure features are described and analyzed. The test results indicate that the stability of the GFRP middle beam and the local strength at the joint between the web and the flange are the main factors in the design of the composite middle beams. Based on the test results, a new-style GFRP middle beam with- I-section and double webs is proposed and designed. Loading test shows that the composite material with I-section and double webs can satisfy the requirements for the globe and local stabilities, and simultaneously the material strengths of the middle beam can also be fully utilized. Maybe the proposed new-style beam is the best section type for the middle beam. Also, local strengthening should be adopted in the middle beam-bolt joint.
Growth and Photodegradation Characteristics of Nano-Crystalline Titania Coating Prepared by MAO
Authors: Wang Jian Bo , Lu Jun , Cheng Xin Yi
Published: November 2010

Nano-crystalline titania coatings were prepared by microarc oxidation (MAO) on titanium alloy (TC4) substrates in Na2CO3-KF electrolytic solution. The coating thickness was measured by an optical microscopy with a CCD camera. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to characterize the microstructure and phase composition of coatings. The results show that the coatings are porous nano-crystalline structures mainly composed of anatase and rutile (TiO2). With the increase of anode voltage, both the relative contents of rutile and the sizes of micropores increase gradually, whereas the sizes of the nano-crystalline decrease first and then increase. The prepared samples were employed to study the photo degradation characteristics of Rhodamine B. The results show that the photodegradation performance of the samples prepared under 220V is the best.
Analysis of Electromagnetic Inverse Model of Resistance Spot Welding
Authors: Fan Nai Feng , Luo Zhen , Li Yang , Xuan Wen Bo
Published: November 2010

Resistance spot welding (RSW) is an important welding process in modern industrial production, and the quality of welding nugget determines the strength of products to a large extent. Limited by the level of RSW quality monitor, however, RSW has rarely been applied to the fields with high welding quality requirements. Associated with the inversion theory, in this paper, an electromagnetic inverse model of RSW was established, and the analysis of influence factors, such as the layout of the probes, the discrete program and the regularization method, was implemented as well. The result shows that the layout of the probe and the regularization method has great influence on the model. When the probe is located at the y direction of x-axis or the x direction of y-axis and Conjugate Gradient method is selected, a much better outcome can be achieved.
The Influence of Surface Barrier to Critical Current of HTSC’s
Authors: Liu Gang
Published: November 2010

Based on the nonlinear flux creep model, the V-I curves are numerically studied considering the influences of surface barrier. The influences of surface barrier to critical current of the high temperature superconductors (HTSC’s) are carried out. The results show that as the strength of surface barrier increases, critical current increases. Besides, with the existence of surface barrier, history effect was found in V-I loop, which indicates that surface barrier is one of the important factors to make history effect.
Rapid Forming of Hydroxyapatite-Silica Ceramics
Authors: Liu Fwu Hsing , Ni Tsui Yen , Shen Yung Kang , Lee Jeou Long
Published: November 2010

This paper proposes a solid freefrom fabrication (SFF) technology for fabricating hydroxyapatite(HA)-silica ceramics, which can generate porous three-dimensional physical objects. The HA powder and the silica are mixed with water into slurries form as raw materials. The slurries are paved by a scraper to from a thin layer which is selective scanned by a laser beam according to the cross-section of a 3D model. The HA particles are embeded in the sintered silica matrix to form green parts via a suitable range of process parameters. The benefits of this process are: bio-ceramic parts can be built by lower laser energy and faster fabricating speed. Following a subsequence heat treatment process has been developed to optimize the crystallization process and to increase the strength of the sintered parts. The parts were analyzed by an Atomic Force Microscope (AFM) to determine the surface roughness. The results obtained indicate that the proposed process was possible to generate multilayer, overhanging, and porous structure with brittle property but sufficient integrity for handling prior to post-processing. It was possible to produce the porous structure from the proposed hydroxyapatite-silica ceramics, which had a greater potential for possible bone scaffolds fabrication.
Design for Assembly in Concurrent Engineering - A Case Study on its Application: Glass Block Holder and Glass Mold
Authors: Gerdemeli Ismail , Fetvaci Cuneyt , Kayaoglu Eren
Published: November 2010

The aim of this study is to define Design For Assembly (DFA) technique in the light of concurrent engineering methodology, determine the principles and manifest these principle effects on an application through comparison. There is a re-design process in glass block holder and blocks of an automation machine which is used in glass production industry. The 3D models of the original and new design have been made by using SolidWorks 2006. The new design is made in the light of DFA and with paying attention to the Boothroyd & Dewhurst method. The re-designed mold is applied to large volume production process and healthy results were obtained. At the end of this part, the tables which are derived from the old and new data are prepared and their comparison is made.
Influences of Strain Rate on Copper Nanowire in Tension
Authors: Chang Chao Cheng
Published: November 2010

This study uses molecular dynamics simulations with an embedded-atom method (EAM) potential to investigate the effects of strain rate on a copper wire in tension at the nanoscale. By averaging the atomic stresses over the entire system, the stress-strain curves for the nanowire were predicted. The results show that an elastic region clearly exists in the early deformation of the copper nanowire and the elastic modulus is about two times of the value measured at the macroscale. The yield stress of the nanowire increases with the strain rate. Moreover, the evolution of the crystal structure was investigated in terms of the radial distribution function and the local atomic order was also examined by the common neighbour analysis. The dislocations and recrystallization processes inside the nanowire have been observed. The simulated results reveal the process of the fracture of copper nanowire in tension.
Ultrasonic Welding of Polyamide and Polycarbonate Plates
Authors: Schaefer Frank Helmut
Published: November 2010

Ultrasonic welding of plastic is state-of the-art technology. The thermal rise in the bonding area is produced by absorption of vibrations introduced. In the contraction area, frictional heat is produced so that material plasticizes locally, forging an insoluble connection between both parts within a very short period of time. The prerequisite is that both working pieces have a near equivalent melting point. To be able to extend the known influences and limits due to ultrasonic welding of plastic and metal parts the bonding process is of interest. In this study, the author applied the ultrasonic welding method to polyamide and polycarbonate plates and investigated the temperature distribution of the weld and the resulting flexural behaviour without the consideration of an optimum joint geometry.