bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Grain Growing Process of Zinc-Aluminium Alloy under High Pressure
Authors: Qu Ying Dong , Li Rong De , Bai Yan Hua , Li Qiang , Yang Hong Wang , Wang Rui Chun
Published: August 2011

Under high pressure of more than 1GPa, the grain growing process of Zinc-Aluminium (ZA) alloy is difficult observed by experimental method, therefore numerical simulation method is used to observe grain growing process of ZA alloy. Pressure as a important variable is leading-in thermodynamic parameters of ZA alloy, then solute diffusion and redistribution model, grain nucleating and growing model are present, and dendrite growth module is applied to describe grain growth. The simulation results of grain growth process under high pressure are demonstrated: In the initially solidification stage, grains are equiaxed growing process, after 15s solidification time, dendrite arm size are not equal, the reason is there are nonhomogeneous temperature fields around grains, which make some grains appear fast growing velocity, even it can be observed that dendrite arm of different grains are meet each other at 25s solidification time. Comparing simulated microstructure with experimental microstructure under 2GPa high pressure, it shows both grain size and grain distribution are similar, proving that the grain growing process can be well observed by simulation method.
Experiment Study Based on Nano-Ceramic Grinding Wheel Bond
Authors: Zhang Jing Qiang , Pang Zi Rui , Yu Tian Biao , Wang Wan Shan
Published: August 2011

To meet the requirements of super-high speed vitrified bond of CBN grinding wheel that should be low-melting, high strength and multi-foams, performance of nano-ceramic bond were researched in this paper. Four types of bond which major glass components was R2O+RO-B2O3- -Al2O3-SiO2 have been compounded with pure raw chemical materials. In order to improve the strength of bond, nano-materials were added into formulations of the vitrified bond. And experiments results showed that compared with traditional vitrified bond the new nano-ceramic bond had a significant advantage at its refractoriness, expansion coefficient, surface morphology and bending strength. Especially, the bending strength of 4# nano-ceramic bond had reached to 83.75 MPa and its refractoriness was 790 °C. It proved that 4# nano-ceramic bond was more suitable for super-high speed CBN grinding wheel.
Measurement System of Contact Angle between Molten Steel Droplet and Refractory Material
Authors: Qiu Xiao Lin , Chang Guo Wei , Chen Shu Ying , He Jian Guo
Published: August 2011

The distinct images of molten steel droplets were obtained utilizing a home-made experimental equipment, and the method which measures the contact angle between the molten steel droplet and the refractory material using a computer image processing technology and Visual C++ language was represented, meanwhile the measurement system of the contact angle was developed. The results show that the maximum deviation of the measurement system is 0.13° comparing with the actual measurement results, the minimum deviation is 0.03°, and the mean deviation is 0.06°. Under this experiment conditions, the contact angle increases 1.2° when the quality of sample increases from 0.2g to 0.8g at 1550°C, and the contact angle increases 2.3° when the temperature increases from 1550°C to 1600°C for the sample of 0.2g.
Control of Liquid-Drop Surface Shape in Melt
Authors: He Jian Guo , Chang Guo Wei , Chen Shu Ying , Qiu Xiao Lin
Published: August 2011

The carbon steel samples of great quality can not be melted using a high-temperature confocal scanning laser microscopy(HTCSLM). On account of only arc surface of the tiny liquid-drop top is observed, it is difficult to obtain distinct images. The shape variation of the tiny liquid-drop is studied experimentally in this article. The results show that the shape of the liquid-drop will be changed at 1600°C, when the carbon steel sample of 0.5g is laid on the Al2O3sloping of 15 degrees. Though the radius of curvature of the liquid-drop top surface is obviously enlarged, the impact of improving the surface shape of liquid-drop through the gravity flow of tiny liquid-drop is finite. For the carbon steel sample of less than 0.8g, the hanging drop is automatically formed in the melting process under the condition that the gap between the solid sample and Al2O3single crystal plate is 0.3mm, and the shape retains invariant when it is hold for 20 min at 1600°C. The contact surface between the sample and Al2O3single crystal plate is 24mm2.
Crack Tip Opening Displacement of X100 SAWL Pipe
Authors: Xiong Qing Ren , Liu Jun , Zhang Jian Xun , Feng Yao Rong , Zhao Wen Zhen
Published: August 2011

The fracture toughness of different zones of X100 SAWL pipe was studied by three-point bend test method under different temperature. At the same temperature, the crack propagation resistance and tear modulus of X100 SAWL pipe distributed as: base metal>HAZ>weld bead, and the distribution of the CTOD value of X100 SAWL pipe is :base metal >weld bead >HAZ. Further investigation was conducted to analyze the decrease of fracture toughness (especially low temperature fracture toughness) and the occurrence of local unstable phenomenon in HAZ specimens.
Study on the Sewage Treatment by SBBR-BAF Filled with Ceramic Filling
Authors: Li Wei , Wei Wei , Liu Yuan , Wang Tian Jiao
Published: August 2011

In the biological aerated filter, the removal efficiency of phosphorus is poor, while the efficiency of organics and nitrogen are very well. In order to solve these problems, the sequence bio-film reactor connects to traditional biological aerated filter, ceramic filler was added to the system, study the effect of bio-film culturing and biological disposal capacity .Control intermittent time of anaerobic and aerobic and aeration volume, the removal effect of COD 、nitrogen and phosphorus are good in the sewage . The results show that anaerobic and aerated time are 3h and 4h in SBBR, the removal efficiency of COD、NH4+-N、TN and TP are 90.07%、85.12%、81.74% and 83.63%, the concentration are 31.37mg/L, 5.15㎎/L, 6.60㎎/L and 1.10㎎/L separately. All of these satisfy theⅠ-B criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). The system of SBBR-BAF run stably, removal sewage perfectly, avoid return and mud, save energy consumption.
Factors Analysis of Non-Aqueous Electrolytic Extraction of Ultrafine Non-Metallic Inclusions
Authors: Li Hui Gai , Gong Yue , Yang Cun Bo , Zheng Shao Bo , Zhai Qi Jie
Published: August 2011

It will be no damage for small non-metallic inclusions by non-aqueous electrolytic technique. However, there are some unsolved problems: the interference of by-product, the corrosion of small inclusions and the low efficiency. PH value, colloid and electrolytic efficiency were discussed in this paper to optimizing electrolysis parameters. Finally, ultrafine non-metallic inclusions were extracted successfully with high efficiency. The results showed that complex oxides and sulfides were kept well and the contents of by-product were reduced distinctly. Three dimensional morphology inclusions were observed with clear background.
Metallurgical Behavior of Adjusted Converter Slag in Reduction Process
Authors: Chen Min , Tian Zhen , Yu Qing Xian , Gao Zhen Feng
Published: August 2011

The metallurgical behavior of adjusted converter slag components during the selective reduction process were investigated by thermodynamic calculating with different modified slag composition, addition of reducing agent and reduction temperature. The activities of main slag components were drawn from the calculated values. The results showed that the activity of SiO2increased with increment of its mass fraction in slag. The solubility of SiO2increased with increment of temperature. The selective reduction was promoted by selecting the appropriate amount of modifier. Reduction order was elucidated in this paper, Fe was reduced from the slag followed by P, Mn and Si and the reduction rate of Si could reach about 51%. The metal phase was rich in Fe, Si, Mn and P as a result of the selective reduction.
Effect of Boron on Microstructure and Mechanical Property of High Grade Pipeline Steel
Authors: Tang Xing Chang , Kang Yong Lin , Bo Yan Yan , Fan Lei
Published: August 2011

The correlation among boron, microstructure and mechanical property of the X120 pipeline steel was investigated in this study. The mechanical properties of the steels were tested with quasi-static tensile testing machine. The microstructure of the steels with different boron contents was observed with scanning electronic microscope (SEM) and transmission electronic microscope (TEM). The result shows that by adding a small amount of boron the mechanical property of pipeline steel can be improved effectively.
Theoretical Analysis of the Influence of the Electron Pulse Modification on Al-Cu-Mn Alloy Initial Aging Stage with Valence Electron Structure
Authors: Cao Li Sheng , Liu Jing Xue , Lin Cheng
Published: August 2011

Statistical values of valence electron structure parameter for phase structures of super saturation solid solutions in the initial aging stage of Al-Cu-Mn alloy were calculated by using the Empirical Electronic Theory in solid and molecules (EET), then the influence of various kinds of unit cells on the aging initial stage of the Al-Cu-Mn alloy subjected to the electron pulse modification was analyzed. The results show that the a-Al-Cu-Mn phase structure unit (cell) with larger atomic distortion provides the driving force for the saturated Al-Cu-Mn alloy to form G.P quickly and results in the increase in the primary nucleus of Al-Cu-Mn alloy; thus the a-Al-Cu-Mn phase structure unit (cell) playes an important role in the improvement of alloy aging. After the application of pulsed electric field into Al-Cu-Mn alloy melt, the movement of atoms is accelerated, and the number of segregation units of Al-Cu-Mn is increased, as a result the number of the second phase is increased; generating the remarkable aging strengthening.
The Effect of Mixture Parameter on the Properties of SCC
Authors: Liu Hong Yan , Qi Jin Gang
Published: August 2011

It is not difficult to prepare self-compacting concrete (SCC) in laboratory now. The problem researchers faced is how SCC can be popularized in civil engineering. A modified densification mixture design algorithm (DMDA) is used in this study to prepare the control mixture. And on the basis of the system analysis for exist studies, 6 factors are chosen as experimental factor and 25 experiments are designed by orthogonal design experiment method. The results analysis indicates that only 3 factors are significant on SCC and their recommend value is obtained respectively. It may shed light on the application of SCC.
Micronano Structure and Mechanics Behavior of Mosquito’s Proboscis Biomaterials with Applications to Microneedle Design
Authors: Kong Xiang Qing , Wu Cheng Wei
Published: August 2011

The mouthparts of female mosquitoes have evolved to form a special proboscis, a natural biomicroelectromechanical system, which is used for painlessly penetrating human skin and sucking blood. The structure of the mosquito fascicle is observed using a scanning electron microscope, and the mechanical property of the labrum and maxillae, two of the most important parts of the mosquito’s fascicle is studied. The micronano structure and the special biomaterials of the mosquito’s proboscis make the mosquito penetrate easily into human skin with a surprising low force, which is measured to be only tens of micro-Newton. Our obtained results are helpful for the optimum design of the microneedles and transdermal drug delivery system.
Semi-Solid Billets of AZ91D Magnesium Alloy Prepared by Forward Extrusion/Equal-Channel Angular Pressing
Authors: Zhang Guang An , Ma Cui Yan , Zhou Qi
Published: August 2011

Stress-induced melt activation (SIMA) has a certain advantage during the preparation of semi-solid billet of Mg alloy. However, Equal-Channel Angular Pressing (ECAP) only can produce small billet by several channels to achieve large equivalent strain. To conquer this problem, the forward extrusion/(ECAP) method, a new process for preparing semi-solid Mg alloy was proposed. And the feasibility of forward extrusion/ECAP was analyzed. This new method simplified the processing procedure for providing commercial semisolid billets of Mg alloy. The experimental dies and experimental procedure were designed. The effect of extrusion ratio and equivalent strain on the microstructure of semisolid Mg alloy was investigated. It was found that when the extrusion ratio was larger than 10, the semisolid microstructure is refined, with increasing extrusion ratio, the microstructure is refined further.
Effects of Different Melt Modification Techniques on the Structure and Properties of Silicon Brass
Authors: Zhao Zuo Fu , Qi Jin Gang , Dai Shan , Zhang Dong Jun , Yang Hai Ming , Wang Jian Zhong
Published: August 2011

The melt of nonleaded free-cutting brass is modified by the electric pulse and the effects on the solidification structure and properties of Silicon Brass are studied with different Bi contents and under different pulse parameters. The results show that the varieties of Bi contents and pulse parameters have a greater impact on grain size and microstructure uniformity of the brass. After silicon brass with 0.5% Bi is modified by electric pulse, the Bi grain size is reduced to 5μm from 30μm, and its shape is changed into being granular from worm-like or long-strip-like, distributed more evenly in α phase and α phase boundary, and a few of which goes into the β phase matrix.
Molecular Dynamics Simulation Study of the Structural Evolution in the Cu-Ni Coalescence Induced by Ni Heterocluster
Authors: Li Guo Jian , Wang Qiang , Zhang Ying Jie , Cao Yong Ze , He Ji Cheng
Published: August 2011

Molecular dynamics with an embedded atom method was used to study the coalescence of heteroclusters at different temperatures. The coalescences between heteroclusters and homoclusters were compared. The results showed that: the coalesced complex of two liquid heteroclusters separated into two small droplets at or above a certain temperature which was much higher than the melting temperature of each cluster. When the temperature was lower than the value, the ordered alignment on the close packed (111) facet was induced by Ni cluster. These phenomena did not occur during the homoclusters coalescence.
Effects of Electric Pulse Modification on the Hot Tearing of Al-5%Cu-0.8%Mn Alloy
Authors: Wang Bing , Tang Li Dan , Wang Jian Zhong , Qi Jin Gang
Published: August 2011

It was investigated that the effect of electric pulse modification (EPM) on the hot tearing of Al-5%Cu-0.8%Mn alloy. The results indicate that hot tearing tendency of all samples can be reduced treated by electric pulse with different parameters, moreover, hot tearing stress of alloy with EPM was enhanced 3 times or so than that of samples without treatment. Decreasing the quantity of eutectic in grain boundaries, decreasing the end-solidifying temperature of the alloys, and refining the grains are main causations for increasing hot tearing resistance of Al-5%Cu-0.8%Mn alloy by electric pulse modification.
Characterization and Analysis of Ethylene-Propylene Copolymers
Authors: Wang Hong Bao , Yue Dong Mei , Gao Yue Kai , Wu Si Zhu
Published: August 2011

The compositions of a series of ethylene-propylene copolymers were quantitatively determined by13C-NMR at 300K in the solvent o-dichlorobenzene. The monomer composition and sequence distribution were analyzed. The glass transition temperatureTg, half temperature of decomposition and crystallinity were found to be closely related to the sequence structures of methylene. The Tg, half temperature of composition, and crystallinity appeared an abrupt change when the methylene length arrived 7~8 because of the movement of the ethylene segments. Also, theTgof copolymers were simulated according to the monomer compositions. The simulatedTgtended to decrease with the increasing methylene, which was opposite to that of experimented. That was due to the increased crystallization along with the growth of methylene length. While the polymer was amorphous constructed in the simulation, theTgtended to decrease with the increasing soft segment methylene.
Effect of Temperature on Geometric Accuracy of AZ31 Profile during Warm Pre-Tension Rotation Bending
Authors: Xiao Han , Zhang Shi Hong , Liu Jin Song
Published: August 2011

A warm pre-tension rotation bending process is presented to bend the AZ31 profile. A 3D elastic-plastic thermo-mechanical coupled finite element model is established to investigate the effect of forming temperature on the geometric accuracy of the profile. The results indicate that with increasing forming temperature, the springback angles decrease from 8.37° to 7.2°; the bending radii decrease from 90.69 mm to 89.67 mm; the cross-section distortion of the bent profile increases.
Synthesis and NLO Properties of Calix[4]Arene Derivatives
Authors: Fang Ming Feng , Lu Guo Yuan
Published: August 2011

A novel calix[4]arene chromophore 1 was synthesized by introduction of two D-π-A units (4-nitrophenyl)azophenyloxy groups) on the lower rim of calix[4]arene. The measurement results of hyper-Rayleigh scattering (HRS) and UV-vis spectra show that the static first molecular hyperpolarizability of the chromophore 1 is more than two times that of the corresponding mono-D-π-A unit reference compound 4-(4-nitrophenylazo)phenol 2, without causing red-shift of absorption band.
Negative Thermal Expansion of Gd2Fe16.5Cr0.5 Compound with Th2Ni17-Type Structure
Authors: Hao Yan Ming , Liang Fei Fei , He Xiao Hong , Zhao Wu Yan , Qin Yue Ting , Wang Fang
Published: August 2011

The thermal expansion and the Curie temperature of Gd2Fe16.5Cr0.5 compound have been investigated by means of x-ray diffraction and magnetization measurements. The result shows that the Gd2Fe16.5Cr0.5 compound annealed at 1243°C has a hexagonal Th2Ni17-type structure. Cr atom substituting for Fe atom can increase the Curie temperature obviously. In magnetic state, an anisotropic anomolous thermal expansion was observed. Along the c-axis, the average linear thermal expansion coefficient αc=-2.79×10-6/K in the temperature range 294-472K, and αc =-3.09×10-5/K in 472-592K. Along the a-axis, the average linear thermal expansion coefficient αa =9.22×10-6/K in 294-552K, and αa =-1.41×10-5/K in 552-592K. In the temperature range 472-592K, the average volume thermal expansion coefficient αv =-2.14×10-5/K. The mechanism of the thermal expansion anomaly of Gd2Fe16.5Cr0.5 compound was discussed in this paper.
Sensitivity to NO2 of ZnO Film Prepared by Electrostatic-Enhanced Ultrasonic Spray Pyrolysis
Authors: Min Jia Hua , Liang Xiao Yan , Wang Bin , Zhao Yue , Guo Yun , Wang Lin Jun
Published: August 2011

The NO2-sensing properties of the ZnO films prepared by EUSP were investigated. Effect of substrate temperature on the NO2-sensing properties of ZnO films showed that the powder-like ZnO film deposited at 550°C was more sensitive to NO2, and the film illustrated good response-restoration property. Besides, the influence of doping amount on the NO2-sensing properties of the ZnO films at 260°C showed that the ZnO:Al film with the Al content of 0.4mol% presented the best sensitivity, and the ZnO: 3mol % Ag exhibited the highest NO2 sensitivity. The dynamic response tests indicated that the ZnO: Al film was of the highest sensitivity to NO2, and the sensitivity of ZnO: Ag film was lowest.
Microwave Absorbing Properties of FeXCo1-X(x=0.7, 0.8) Alloys with Spherical Nanoparticles
Authors: Wang Fei , Zhang Lian Zhu
Published: August 2011

FexCo1-xalloys were prepared by low temperature hydrothermal method. The influence of Fe content on static magnetic and microwave absorbing properties was studied. XRD results show that FexCo1-xalloys are single-phased body-centered cubic (BCC) structure for both 70% and 80% Fe content. The lattice constant of the alloys increases with increasing Fe content. The coercivity decreases with the increase of Fe content. The composites with high resistivity were prepared by homogeneously mixing FexCo1-xalloy nanoparticles and paraffin wax, and their microwave absorption properties were studied.
First-Principles Study on Ga-N Co-Doped P-Type ZnO
Authors: Zhao Hong Sheng , Gu Yu Dan , Zhang Nan , Gao Ya Hong
Published: August 2011

Based on the density functional theory, the structure of pure ZnO, N doped, and Ga-N/Ga-2N co-doped wurtzite ZnO was calculated by using first-principle plane wave ultrasoft pseudopotential method. Electronic structures of these ZnO-based doping syetems were studied. The calculations of band structure, total density of states, and partial density of states show that Ga-2N donor/acceptor co-doped ZnO is easier to implement the p-type ZnO than other cases.
In Vitro Behavior of Magnesium Apatite Coatings in Organic Modified Simulated Body Fluid
Authors: Qi Guo Chao , Shan Feng Jun , Li Qiang , Yu Jing Yuan , Zhang Qu Kai
Published: August 2011

Magnesium apatite (MA, (Ca9Mg)(PO4)6(OH)2) and Hydroxyapatite (HA) coatings were synthesized on Ti6Al4V substrates by a sol-gel dip coating method. Glucose and bovine serum albumin (BSA) were added to the standard simulated body fluid (SBF) separately to form organic-containing simulated body fluids. MA and HA coatings were immersed in standard and organic modified SBF for time periods of 4, 7, 14, 21 and 28 days at 37±1°C. The surface dissolution and deposition behavior of the coatings after soaking were examined with Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The results show that glucose in SBF has no apparent effect on the deposition of new apatite from the solution. BSA in SBF shows retardation effect on the deposition of apatite by forming a protein dominant globular layer. This layer inhibits the further deposition of apatite from SBF solution.
Local Stress-Strain Method for the Effects of Scratch on Fatigue Performances of Cabin Glass
Authors: Ding Hua , He Yu Ting , Du Jin Qiang , Wu Li Ming , Zhang Hai Wei , Shao Qing
Published: August 2011

The three-dimensional finite element model of cabin glass with surface scratch is built using the finite element software ANSYS, which is aimed to analyze the detailed stress around the scratch route tip. Then the fatigue notch factor can be gained through utilizing of results from three-dimensional model, which is followed by the estimation of fatigue life based on local stress-strain method. It is found that the stress around scratch route tip is nearly linearly increased with the increasing of tip depth (0.2mm<h<0.8mm) and the fatigue performances of cabin glass with surface scratch are sensitive to scratch depth. Finally, fatigue tests are carried out with the specimens of different scratch route tip depths, and validation against fatigue life by local stress-strain method and experimental data shows a good agreement, which indicates that the scratch model and the local stress-strain method for the effects of scratch on cabin glass fatigue performances are valid.
Study on Surface Oxidation Behavior of Pourous NiTi Alloy at High Temperature
Authors: Li Qiang , Zhang Xiao Na
Published: August 2011

In this paper, porous NiTi alloy prepared by powder metallurgy method was oxidized at high temperature. The effect of oxidation temperature and time on quality of oxidation layer of porous NiTi was studied. The component and morphology of oxidation layer before and after oxidation at high temperature were analyzed by XPS and SEM. The behavior of Ni ion release of porous NiTi alloy was observed. The results showed uniform and thick oxidation layer was formed on the surface of porous NiTi alloy after oxidation at 550°C for 1h. XPS analysis showed the oxidation layer mainly composed of TiO2, and the thickness of the film was about 180nm higher than that before oxidation. The research on the behavior of Ni ion release showed the Ni release after oxidation can be significantly reduced at simulated body fluid due to TiO2layer.
Broadband ~1.5μm Emission of Er3+ in Heavy Metal Germanium Tellurite Glasses for Optical Fiber Amplifier
Authors: Liu Xiao , Shen Quan , Lin Hai , Yang Dian Lai
Published: August 2011

In Er3+/Yb3+codoped Na2O-ZnO-PbO-GeO2-TeO2(NZPGT) glasses, effective ~1.5mm infrared (IR) emission was investigated under 980nm excitation. Judd-Ofelt intensity parameters Wt (t = 2, 4, 6) had been calculated to be 6.78´10-20, 1.54´10-20, and 1.17´10-20cm2,respectively. The IR emission full width at half maximum (FWHM) is 73nm, and the maximum stimulated emission cross-section (se) is derived to be 7.53×10-21cm2. A figure of merit (FOM) as the product FWHM´se is adopted to evaluate the gain bandwidth. The comparison of FOM in different glasses indicated that Er3+/Yb3+codoped NZPGT glasses were potential materials in developing broadband optical amplifier.
Study on Preparation and Optical Absorption of Ge Doped TiO2 Composite Thin Films by Sol-Gel Method
Authors: Zhou Yan Jun , He Fang , Qi Jin Gang , Wang Yu Lin
Published: August 2011

By using the sol-gel method, TiO2 thin films and Ge doped TiO2 composite thin films were fabricated onto quartz substrates. XRD, XPS and UV-vis were used to characterize the phase structure, the atomic chemical states and optical absorption of these composite TiO2 thin films. XRD results indicate that diffraction peak of anatase is observed in samples. XPS result reveals that there is Ge crystal in Ge doped films which were prepared by sol-gel method, and Ge exists as elemental Ge and GeO2 in the films. The composite TiO2 thin films by sol-gel method exhibits the absorption shift to visible region due to Ge doped TiO2 thin films.
Research on Substitution of Molybdenum by Manganese in Low Alloyed Bainite Ductile Iron
Authors: Wei De Qiang , Liu Ke
Published: August 2011

The low alloyed bainite ductile iron is obtained by alloying and austempering in room-temperature machine oil. The microstructure is investigated. The mechanical properties are discussed. In general, the number of white-bright zones and segregation is increasing with the increasing in the content of Mn, but the impact toughness is decreased. Therefore, the content of Mn is no more than 0.5 wt.%. The microstructure of bainite, martensite and a little retained austenite in the matrix of the ductile iron was investigated by scanning electron microscope (SEM). The hardness and impact toughness of the ductile iron subjected to heat-treatment are 54~56 HRC and 14.2 J/cm2, respectively. The substitution of 0.3~0.5wt.% Mo by 0.7~1.0 wt.% Mn can be realized in the bainite ductile iron.
Preparation of Pd-TS-1 Composite Membrane for Hydrogen Separation
Authors: Guo Yu , Wu Hong Mei
Published: August 2011

Palladium composite membranes have been prepared by improved electroless plating on macroporous α-Al2O3 tubes. TS-1 zeolite layer was introduced in the palladium composite membrane to modify macroporous α-Al2O3 tubes and prevent the diffusion between Pd and alumina. The detailed microstructure and morphology of the Pd-TS-1 composite membrane were examined by SEM and XRD. Moreover, gas permeation performance was tested at the temperature range of 623~773K. Results showed that the H2 permeance and H2/N2 ideal selectivity for Pd-TS-1 composite membrane could be up to 3.7×10-7 mol·m-2·s-1·Pa-1 and 310 at 773K, respectively.
Hemocompatibility of TiO2 Nanoparticles Composite PTFE Coating for Medical Devices
Authors: Xue Li Li , Long Ping , Wei Huan , Liang Ying
Published: August 2011

Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. It has been improved that TiO2has excellent hemocompatibility. In this study, TiO2nanoparticles was added into polytetrafluorethylen (PTFE) resin in order to enhance hemocompatibility of the organic coating. The surface hydrophobicity of the coatings was characterized by contact angle measurement. Systematic evaluation of hemocompatibility, including platelet adhesion and blood clotting, proved that TiO2nanoparticles composite PTFE coating have better hemocompatibility. It is suggested that TiO2nano particles can improve hemocompatibility of organic coating due to its passive surface and chemical stability.
Effect of Synthesis Conditions on Photocatalytic Activities of Nanoparticulate TiO2
Authors: Zhou Yan Jun , Du Hui Ling , Qi Ping , Liu Ai Min
Published: August 2011

In the present study, design of experiments (Orthogonal experiment) was used to find an optimal combination for the factors, which affect the catalytic activity of nano-crystalline TiO2 powder synthesized by sol–gel method. Sixteen kinds of TiO2 powder were prepared by changing three material ratio at four levels. The effects of calcinations temperature on the catalyst activity of TiO2 were investigated by single factor experiments. TiO2 were characterized by XRD. The results of design of experiments are examined by the direct observation analysis. The preparation conditions have been optimized as material ratio nTi(OC4H9)4: nH2O: nHN(C2H5OH)2: nC2H5OH=1:2:2.5:20, mean 16.8 nm TiO2 nanoparticle with anatase structure obtained at 500°C calcination. The photodegradation efficiency of methylene blue in aqueous solution is 99 % under 1g/L catalyst.
Effect of Minor Compressive Deformation in Austenite on Martensitic Transformation in Modified 9-12%Cr Ferritic Steel
Authors: Liu Chen Xi , Liu Yong Chang , Zhang Dan Tian , Dong Zhi Zhong , Ning Bao Qun , Yan Ze Sheng
Published: August 2011

A modified high Cr ferritic heat-resistant steel was developed and subjected to the thermomechanical treatment. The effect of applied stress and temperature on martensitic transformation and microstructure was studied by using high-resolution differential dilatometer and optical microscope. Applied stress raises the amount of defection as dislocation and grain boundary defects, thus elevateMs. Applied stress also lead to the increase of transformation time due to the mechanical stabilization of austenite. Increase of applied stress or temperature would enhance these above effects.
Study of Modified Properties on Electrolytic Phosphate Coatings with Nano-Al2O3
Authors: Hao Jian Jun , Wang Chong Rui , Liu Xin Yuan , Pu Xiao Qin , Dong Chun Yan , Cui Yuan Yuan , Zhang Li Li
Published: August 2011

The properties of nano Al2O3modified electrolytic phosphating film have been studied through using the accelerated corrosion test, electrochemical testing techniques, scanning electron microscope (SEM) and X-ray diffraction (XRD) .The results show that, after adding nano- Al2O3 in electrolytic phosphating bath , morphology of phosphating film surface turned dense flake crystallization from needle crystal morphology of free-adding nano- Al2O3powder, and the value of impedance of the Al2O3incorporated phosphate coating was increased obviously.When the nano- Al2O3concentration was 15mg / L in electrolytic phosphating bath, the value of impedance of the coating is approximately two times larger than the phosphating coating directly formed on the low carbon steel.The corrosion resisting time of the coating was more than 420 s by CuSO4dripping test, and the corrosion current density of the phosphating sample was 1.164μA/cm2，in 3.5% NaCl solution, the corrosion inhibition efficiency reached 96.7%.
Preparation of Special Microstructures by Polystyrene-Block-Poly(methyl methacrylate) Surface Micelles
Authors: Hong Xiao Dong , Liang Bing
Published: August 2011

A simple method of preparing nanotemplates with special microstructures by polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) surface micelles was researched in this study. The self-assembly of surface micelles adsorbed on mica when exposed to the vapors of toluene, acetone and water was studied by atomic force microscopy (AFM) in detail. Results indicate the irregular and spherical structures can be obtained in the vapors of toluene and acetone respectively. Various microstructures ranging from starfish-like to chrysanthemum, torus, cylinder and hat structures can be obtained in water vapor for different time. The special microstructures of PS-b-PMMA can be used as nanotemplates to prepare nanomaterials with special nanostructures.
Study on Polyethylene Glycol Acrylate Crosslinked Gels as Phase Change Materials
Authors: Zhang Hong , Wang Qian Qian , Xiang Heng Xue , Wang Xiao Lei
Published: August 2011

The cross-linking degree of polyethylene glycol acrylate (PEGA) gel by free-radical solution polymerization was investigated in which PEGA was prepared by chemical modification. The structural morphology, crystal property, thermal property and thermostability were investigated using scanning electron microscope (SEM), polarization microscope (POM), differential scanning calorimeter (DSC), and thermogravimetric analysis (TG), respectively. The results showed that the chain segment of PEG had good activity in lightly cross-linked PEGA gel, the crystallization enthalpy of PEGA gel achieved to 122 J/g, and the duration of its soaking time was about 490 s. Furthermore, chain segment of PEG were bound in PEGA gel, but the crystallization enthalpy of PEGA gel achieved to 64.60 J/g, its soaking time was continued for about 430 s. PEGA gel had a better thermal stability below 300 °C.
The Investigation on the Non-Contact Treatment of the Metal Surface Layer by Using Strong Pulse Electromagnetic Field
Authors: Gao Ming , Zhang Li Li , Huang Tao , Lv Meng Ru
Published: August 2011

A strong pulse electromagnetic field was employed to treat the surface layer of several metal materials. The results showed that the treatment of the strong pulse electromagnetic field could modify the microstructure of the region around the crack on the 45# steel surface. It could also make the recovery process occur in the scratch on the brass surface, and make the surface layer of the Wood’s alloy melt in a very shot time. These results indicated that the strong electromagnetic pulse could be developed as an effective non-contact method for the metal surface processing.
A Preliminary Study of Anodization and Electroless Ni–P Plating on AZ80 Magnesium Alloy
Authors: Shi Ping , Han Xue Dong
Published: August 2011

Magnesium alloys are being used as structural components in industry because of their high strength to weight ratio. But their high electrochemical activity and poor corrosion resistance limited their applications. Therefore, surface modifications are needed for protection purpose. This paper studied the anodic micro-arc oxidation and electroless Ni-P plating surface modifications on AZ80 magnesium alloy. The SEM, XRD and EDS were used to characterize the surface coating. It shows that a micro-porous MgO layer with the pores size 5 – 20 μm was fabricated on the bare magnesium alloy. The nodule Ni-P deposition could be prepared on the out layer of MgO with Ni/P atomic ratio being 1.4. The pores in MgO layer could be sealed by the following Ni-P deposition. Therefore the corrosion resistance of the magnesium alloy could be further improved.
Surface Treatment of TC4 by Micro-Beam Plasma Arc
Authors: Yang Rong Juan , Liu Zong De
Published: August 2011

The effect of micro-beam plasma arc (MPA) surface remelting Ti alloy (Ti-6Al-4V) sheets was investigated. The results show that more satisfactory hardened layer could be acquired after MPA scanning process on TC4 titanium alloy. The composition, crystalline structure and micro-hardness in the remelted layer of TC4 were examined by OM, SEM, XRD and Vickers' micro-hardness tests, respectively. There were no micro-cracks or impurity in the treated sample after scanning by MPA. The micro-hardness of the treated samples was significantly improved as compared with the untreated substrates. X-ray diffraction results indicated that the surface remelting layer composed of phases, which was similar to the substrate. The micro-hardness of the surface was improved to 420 HV0.3as compared to 190 HV0.3of substrate. The increased hardness was obtained due to the micro-structural changes caused by rapid solidification owing to the self-quenching effect of the substrate after MPA remelting.
Simulating Study on Microwave Assisted Switching of Ferromagnetic Moment for Grains
Authors: Li Shuang Mei
Published: August 2011

The minimum switching field threshold and switching speed are important parameters for the magnetic recording in writing. This paper presents the dynamic precession of the moments of the grains based on LL equation, and that the impact of the volume of the grain on the switching speed is investigated under the condition of microwave assisted switching of magnetic moment.
Influence of Die Angle on the Extrusion Behavior of 6061Al Matrix Composite Reinforced with SnO2-Coated Aluminum Borate Whisker
Authors: Du Zhi Ming , Zhao Pei Tang , Wang Li Dong , Fei Wei Dong
Published: August 2011

The 6061Al matrix composites reinforced with SnO2-coated aluminum borate whisker were fabricated using squeeze casting method. The composite were extruded successfully at 350°Cwith different die angles. The experiment results illustrate that the die angle have important influences on the extrusion process. The surface quality of extruded composites was improved and the extrusion load was reduced with die angle increasing from 30 to 60 degree. The <111> and <100> textures for aluminum matrix were formed in all extruded composites. The dispersion degree of the <111> texture, the alignment degree and the average length of whiskers increases with die angle increasing. There is a suitable die angle for the optimization of the extrusion process of the present composite.
Research of SiCP/2A50 Composite Materials Creeper Treads Prepared by Liquid Forging
Authors: Du Zhi Ming , Liu Jun , Cao Qi , Chen Gang , Jia Hai Meng , Xie Shui Sheng
Published: August 2011

Microstructure of creeper treads is inhomogeneous when they are produced by way of common casting, which lead to lower mechanical properties. Compound loading and feeding are introduced into the technology of liquid forging. Defects of filling incompletely, shrinkage porosities and cavities are usually appeared in raised part of creeper treads. With feeding amount increased above 5mm, plastic deformation also would be increased, so the microstructure and mechanical properties of raised part were improved and those defects disappeared meanwhile. SiCP/2A50 composite materials were used in order to enhance abrasive resistance and extend their service life. Creeper tread produced by compound loading and feeding could obtain homogeneous and fine microstructure. Average tensile strength and hardness of specimen reached 360MPa and HV115.97 respectively after (500°C×3h) solution treatment, (20min) quenching and (160°C×10h) artificial aging. The results show that inhomogeneous character of microstructure and mechanical properties of creeper treads could be overcome by compound loading and feeding.
Preparation and Characterization of Core-Shell γ-Fe2O3/Au Composite
Authors: Zhuang Wen Chang , Wang Yu Xiao
Published: August 2011

Composites have achieved much attention because of their excellent qualities. Core-shell γ-Fe2O3/Au nanoparticles were prepared by chemical reduction. Their optical properties and morphology were characterized by UV-visible spectrum (UV-vis), X-ray diffraction (XRD) and Transmission Electronic Microscopy (TEM). Furthermore, the average particle size and interface structure were also analyzed using small angle X-ray scattering (SAXS).
Advanced Stab Resistance Fabrics Utilizing Shear Thickening Fluids
Authors: Song Zhen Yu , Zhang Chen , Song Meng , Wu Si Zhu
Published: August 2011

A series of shear thickening fluids (STF) were prepared and characterized by Rheometer. The stab resistance of Kevlar and ultrahigh molecular weight polyethylene (UHMWPE) non-woven fabrics impregnated with STF were investigated and found to exhibit significant improvements over neat fabric targets of equivalent weight. Specifically, dramatic improvements in stab resistance (knife threat) were observed. These novel materials could be potentially used to fabricate flexible body armors which provide improved protection against both stab and ballistic threats.
Synthesis and Microwave-Absorbing Properties of Al2O3 Coated Polyhedral Fe Nanocapsules Prepared by Arc-Discharge Method
Authors: Shi Gui Mei , Zhang Jin Bing , Yu Da Wei , Chen Long Shan
Published: August 2011

Al2O3coated polyhedral Fe nanocapsules were prepared by arc-discharging a Fe-Al(8at%Al) alloy. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy, and network analyzer were employed to investigate the microstructures, compositions and electromagnetic properties (2-18GHz). The reflection loss R(dB) of the nanocapsules reaches to -50.5dB at 7.9GHz with a 3mm thickness, and EM absorption properties(RL<-20dB) in the 5.2~16.1GHz range with thickness range of 1.67-4.7mm. The excellent Microwave-absorption properties of as-prepared nanocapsules are ascribed to shape anisotropy and core/shell structure.
Experimental Study on Strength of Connections to Concrete Filled Tubular in Fire
Authors: Sun Hong Jun , Zhao Li Hong
Published: August 2011

Concrete filled tubular columns are widely used all over the world, due to their significant advantages, including attractive appearance, structural efficiency, reduced column footing, fast construction and high fire resistance without external fire protection. An experimental study has been carried out on the performance of joints between steel beams and concrete filled tubular columns in simple construction under fire conditions. The failure modes of the test specimens were always in the joint regions. Therefore, if the joints are appropriately designed and protected so that they possess sufficient strength, it is possible for the steel beam to develop catenary action and survive very high temperatures even without fire protection.
Study on Mechanical Properties of EPDM/HPVC Prepared by Dynamic Vulcanization
Authors: Liang Bing , Ji Jie Mei , Hong Xiao Dong
Published: August 2011

A thermoplastic elastomer of EPDM/HPVC with excellent properties was prepared by dynamic vulcanization. The effects of the rubber/plastics ratio, the content of plasticizer and vulcanizing agent on the mechanical properties of EPDM/HPVC were investigated in detail. Results indicate when the mass ratio of EPDM/HPVC was 30/70, CPE was 9 phr, sulfur was 0.4 phr, EPDM/HPVC had an excellent mechanical property and aging resistance. EPDM/HPVC prepared by dynamic vulcanization had a typical sea-island two phase structure in which smaller EPDM particle dispersed uniformly in the continuous phase of HPVC.
Dynamic Mechanical Thermal Analysis of Pultruded Carbon Fiber/Resin Composite Cable Cores
Authors: Zhou Zheng Wei , Bai Rui Cheng , Ren M. S. , Chen Lu , Li Ai Jun , Sun Jin Liang , Hu Q. P. , Wang Chuan Bin
Published: August 2011

The viscoelastic property of the CTC composite cores was investigated through dynamic mechanical thermal analysis (DMTA) in single cantilever mode. The effect of the frequency on the glass transition temperature (Tg) was studied. The results show that the peaks were shifted to higher temperatures with increasing frequencies. Tgof CTC was approximately 180 °C, much higher than that of a home-made composite core (Composite I). The activation energy ΔH of CTC is also greater than that of Composite I. The CTC sample exhibit better stiffness and toughness.
Effect of DLC Film on Tribological Properties of Carbon/Carbon Composites
Authors: Ren J. W. , Bai Rui Cheng , Li H. , Li Ai Jun , Ren M. S. , Sun Jin Liang
Published: August 2011

The effect of DLC film on tribological properties of C/C composites was investigated with a ball-on-disk tribometer in dry air, compared with the result of specimen without DLC film. The DLC film was prepared on the surface of C/C composites substrate by plasma enhanced chemical vapor deposition method (PECVD). After PECVD, structural characterization of the film, adhesion strength of film to substrate, surface morphology and linear wear were studied by Raman spectroscopy, Rockwell-C apparatus, Scanning Electron Microscopy (SEM) and Optical Microscopy (OM), respectively. The result showed that the film deposited on the surface of C/C substrate exhibited typical Raman spectroscopy fingerprints of DLC films and a good adhesion to the substrate surface was found. A stable friction coefficient was observed during the friction tests. With the DLC film, the friction and wear properties of C/C composites were improved significantly. The average friction coefficient of the C/C specimen with DLC film (0.08637) was reduced by 65.56% than that of the one without DLC film (0.2508) and the linear wear was decreased by 84.7% ( from 148.47μm to 22.71 μm) as well.
Roll Casting of a Wire Inserted Strip
Authors: Haga Toshio , Takahashi Kenta , Kumai Shinji , Watari Hisaki
Published: August 2011

Casting of a wire-inserted strip was tried by a downward melt drag twin roll caster. Some numbers of wires of 0.3 mm diameter were inserted. Effects of the wire-interval, matrix alloy and melt temperature on the ability of the insertion of the wire were investigated. Minimum interval of the wire, with which the insertion of the wires was able, was 1.6 mm. Insertion of the wire became easy as the roll speed becomes higher. Superheat of the melt was not important factor for the insertion of the wire.
Effect of Solution Concentration on Growth and Photoluminescence of ZnO Nanorod Arrays
Authors: Wang Jian Zhong , Tang Li Dan , Wang Li Li , Wang Bing , Du Hui Ling
Published: August 2011

Well-aligned ZnO nanorod arrays had been successfully prepared by using hydrothermal methods. XRD and SEM analysis showed ZnO nanorod arrays had well orientation along the [0 0 1] direction of ZnO nanorods. The length to diameter is biggest among these samples and is about 25 when solution concentration is 0.8mol/l. The UV emission caused mainly by exciton combination. Furthermore the formation mechanism of ZnO nanorob arrays was studied in detail.
Study on the Friction Properties of Porous Al2O3 Ceramic/ Al2O3 Ultrafine Particle/ Epoxy New Composites
Authors: Yu Jing Yuan
Published: August 2011

Porous Al2O3ceramic/Al2O3ultrafine particle/epoxy new composites were fabricated using the ordered Al2O3porous ceramic as the frame. The effects of three-dimension interpenetrated Al2O3ceramic, load, and sliding velocity on friction coefficient and wear rate of the composites were studied. The results showed the new composites had better wear resistance compared with Al2O3ultrafine particle/epoxy composites. The friction coefficient and wear rate of new composites with the porous Al2O3ceramic frame of 16.8% were 0.32 and 0.76×10-6mm3/N-1m-1, respectively. The new composites had stable friction coefficient and low wear rate with the change of load and sliding velocity, which is due to the porous Al2O3ceramic frame as undertaker of load during friction process.
Mechanical Properties and Wear Behavior of Polypropylene/Carbon Nanotube Nanocomposites
Authors: Liu Yan Hui , Gao Jing Long
Published: August 2011

Polypropylene(PP)/carbon nanotube(CNTs) nanocomposites with different CNTs fraction were prepared by the melting blend method. The effects of CNTs content on the wear properties and mechanical properties were mainly investigated. The results show that the friction coefficient of the nanocomposites decreased as the concentration of CNTs is increased. With increasing CNTs content, tensile strength, ultimate strain, compact strength and Young’s modules increase firstly and then decrease. For the composite with an effective CNTs content of 3 wt, its tensile strength, ultimate strain, compact strength and Young's modules were improved by 72, 44.4,88 and 37 %, respectively, as compared to PP.