bluuebunny/crossref_metadata_2025 huggingface dataset:
Crushed Product Characteristics of Low-Grade Hematite in High-Pressure Grinding Roller
Authors: Liu Lei , Han Yue Xin , Yuan Zhi Tao , Li Li Xia , Tan Qi
Published: November 2010

As an ultra-fine crushing equipment, High-pressure Grinding Roller (HPGR) has unique advantages in crushing refractory ores, owing to its high efficiency and low energy consumption. Low-grade hematite ores from Anshan were crushed by a laboratory CLF-25-10 HPGR with different applied load, roll speed and feed moisture. The different operating factors on the fine crushed products characteristics were investigated and the suitable operating parameters were obtained. The results showed that the product became finer and specific grinding energy increased with applied load increasing, while the capacity did not vary obviously. The capacity was proportional to the roll speed, while product finess and specific grinding energy didn’t change significantly. The moisture of feed was beneficial to coarse particles crushing and went against fine particles crushing. Specific grinding energy increased and capacity increased and then decreased with the increase of feed moisture. It was obtained that applied load of 5.2N/mm2, roll speed of 0.18m/s and feed moisture of 5% were suitable to crushing effect. At these conditions, the percent of -0.074mm production was 21.84%, P80 of product was 2.55mm, specific grinding energy was 1.081Kwh/t and capacity was 1.521t/h.
Development of the Research on High-Power WLEDs
Authors: Hou Qian Qian , Zhang Pei Xin , Zhang Ming Fang , Lu Zheng Wu , Ren Xiang Zhong
Published: November 2010

Compared with traditional lighting, LED has many unparalleled advantages, and is considered to be the most promising green light which may be able to substitute incandescent and fluorescent lamps. The requirement of LED's luminous efficiency grows with its increasingly application in the lighting field. This paper summarizes the development of gaining approaches of Power-type WLED and their respective advantages and disadvantages; analyses several effective programs which can improve luminous efficiency, including changing substrate materials as to enhance the heat-release performance as well as the impact of chip structure design, the packaging materials and technology or other factors; proposes a new LED packaging material- inorganic fluorescent glass, which is expected to simplify the packaging process greatly, at last, there is an expectation of High-power WLED in future application.
Experimental Study on Extracting Humic Acid from Lignite
Authors: Jiang Peng Wei , Ma Zhi Jun , Han Yue Xin
Published: November 2010

Humic acid has been extensively used in the fields like industry, agriculture, medicine, environment protection, etc. As a kind of potential organic resources that being developed and utilized, humic acid is drawing more and more attention from the world. China is abundant in coal resource; the lignite of China contains a lot of humic acid. Extraction humic acid from lignite creates favorable conditions for the development of coal industry and agriculture industry, has broad utilization prospect. By combining the method of nitric acid preoxidation and the method of alkali solution and acid eduction, the humic acid was extracted from the lignite. The orthogonal experimental method and FTIR were integrated in this study. The influences of nitrate concentrations, acid-coal proportion, oxidized temperature, oxidation time, extraction liquid concentration, liquid-solid ratio, extraction temperature and extraction time etc. on the process of extracting humic acid were examined. The results indicate the optimal processing condition can achieved when using sodium pyrophosphate and sodium hydroxide solution as the extraction agents, the rate of humic acid production can reach to 39.25%. And the total content of humic acid production can reach to 46.14%.
Experimental Study on Microwave Pretreatment with some Refractory Flotation Gold Concentrate
Authors: Su Xiu Juan , Mo Wei , Ma Shao Jian , Yang Jin Lin , Lin Mei Qun
Published: November 2010

The microwave pretreatment of a typically refractory flotation gold concentrate was investigated. The results demonstrated that a maximum gold recovery of 97% was achieved, and that gold recoveries of the refractory gold concentrate quickly increased to the maximum with microwave heating time. Adding additives during microwave heating process was helpful to improve the leaching rate of gold, and the effect of microwave heating with single NaOH on the leaching rate of gold is not better than that of NaOH combined with other additives.
SiC/Si - MoSi2 /MoSi2 Oxidation Protective Coating for Carbon Material at 1700°C
Authors: Zhao Ju An
Published: November 2010

A multi-layer coating SiC/ Si - MoSi2 /MoSi2 with good oxidation resistance has been developed by using the slurry-sintering method on the surface of graphite to improve the oxidation resistance performance at 1700 °C for more than 200 h. Microstructure and anti-oxidation property of the as-received coating were investigated. It was found that functionally gradient SiC/ Si - MoSi2 /MoSi2 coating was formed on the surface of the graphite substrate. The coating characterized by excellent thermal shock resistance can effectively protect the graphite from oxidation at 1700 °C for 200 h. The mechanism of the oxidation resistance of the coated graphite is also dicussed, and a dense SiO2 layer was formed on the surface of coating at 1700°C during the isotheral oxidation, which can protect graphite from oxidation at longer time.
Experimental Study on Concrete under Uniaxial and Biaxial Compression
Authors: Zhang Min Xia , Xu Ping , Wang You Kai , Xu Hai Bin
Published: November 2010

In order to study on mechanical character and damage mechanism of the concrete under different loading conditions, the uniaxial and biaxial compression experiment of concrete is investigated by Isotropic Biaxial Loading System of Henan Polytechnic University. The experimental results show the damage of the concrete under uniaxial compression is shear damage, however the damage of the concrete under biaxial compression is tension-shear damage; biaxial compression stress-strain curves of concrete are similar with those of concrete and can equally be divided into three stage; as the result of the intermediate principal stress, 1:1 biaxial compression strength increased 56.12% and 13.30% than that under 2:1 biaxial compression and uniaxial compression, at the same time 2:1 biaxial compression strength increased 37.80 % than that of the uniaxial compression.
Experimental and Numerical Investigation into Dynamic Spall Damage of Porous Phenolic Composites
Authors: Zhu Zhi Gang , Wang Zhi Liang , Li Yong Chi
Published: November 2010

A damage evolution law for porous phenolic composites is developed by using phenomenological point, which along with the improved Johnson-Cook model is then implemented into a finite difference code for one-dimensional strain wave problem. The velocity history of free-face particle is recorded and correlated with the simulated result to evaluate the damage parameters. Good agreement shows that the proposed damage evolution law and spall rule are feasible. Besides, the relationships between the striking velocity of flyer and the spall thickness as well as spall time are investigated. This study provides a methodology to quantify the damage evolution of phenolic composites under impact loading.
Performance Test of N80 Expandable Casing
Authors: Yang Bin , Zeng De Zhi
Published: November 2010

A more comprehensive,systematic experimentical ground tests of the expansion process of expandable casing were performed. In the tests, 6 5 1/2"N80 casings were selected, of which five had been carried out expansion tests , another one casing was used to test the collapse strength , not been expanded. In the course of the tests,some important parameters of the expandable casing were measured before and after expansion,including the inner and outer diameter, wall thickness, ovality, wall thickness of inequality and the axial deformation, etc..These data provide a reliable basis for the mechanism research of the N80 casing expansion. After expansion tests, these six casing pipes had been performed the collapsing tests in Xi'an Tubular Goods Research Institute of CNPC.The test results show that after expansiong the collaps strength of expandable casing get decreased compared with unexpanded casing which provides a practical basis and reference for the design of expandable casing.
Numerical Simulation of Thermal/Mechanical Coupling in Laser Transmission Microjoining of PET and Titanium
Authors: Xu Zhen Kai , Liu Hui Xia , Li Pin , Song Xin Hua , Wang Kai , Wang Xiao
Published: November 2010

Laser transmission microjoining of two dissimilar materials has become a very significant technique. In this research, a numerical method is developed using finite element technique to determine the condition of joining two dissimilar materials namely Polyethylene terepthalate (PET) and titanium. First the model is used to optimize the laser parameters like laser traveling speed and power to obtain good bonding. A good combination is achieved at the power of 8W and laser traveling speed at 150mm/min.After the verifications, the profile of residual stress of the laser microjoint has been calculated using the developed model. The residual is low near the centerline along the traveling laser beam, and a higher values is away from the centerline at the x-direction shown by the contours on the PET surface. Higher residual von Mises stress near the centerline along the traveling laser beam and the stresses reduce as the distance away from the centerline.
Preparation and Characterization of Polypyrrole/Attapulgite with Organic Surface Modification Conducting Composite
Authors: Feng Hui Xia , Liu Sheng Li , Zhang Jian Qiang
Published: November 2010

Attapulgite was organic surface modified with silane coupling agent (KH570) and acetone, with ferric chloride (FeCl3∙6H2O) as the oxidant, sulfamic acid(SA) as dopant, prepared polypyrrole/attapulgite with organic surface modification conducting nano-composite materials (PPy/ATTP-KH) by chemical oxidation polymerization, and using IR, XRD and SEM characterization methods to characterize Internal structure of composite materials obtained. The results show that in the condition of n(Py):n(FeCl3∙6H2O):n(SA) =1:1:0.5, and with the increase of contents, composite conductivity increased and then decreased, when the contents of attapulgite is to 50%, the conductivity reaches maximum 30.0 S•cm-1. We can see from the IR spectrum, silane coupling agent and hydroxyl of attapulgite surfaces have a chemical bonding, and plays a good modification to the surfaces of attapulgite, Thereby enhancing the conductivity of the composite materials.
Research of Technology Parameters on Pipe Axis’ Hot Extrusion Based on Numerical Simulation
Authors: Chen Kun , Chen Pei , Luo Quan Guo , Liu Zhao Tun
Published: November 2010

A typical parameterized model of pipe axis’ secondary necking in hot extrusion process was built，and the evaluation index of forming effect was proposed. Through using revised constitutive equation in Ansys model combining the method of numerical simulation, several mainly hot extrusion process parameters’ influence on forming effect were analyzed, such as friction, temperature and extrusion speed. The prediction equation of forming effect was worked out by numerical fitting, which provided a feasible way to get the better parameters in hot extrusion process. The experiment shows that the parameters obtained from equations can have a good guide on pipe axis and also other similar workpiece’ s hot extrusion process.
Effect of Internal Pressure Path on Wall Thickness of AZ91D Pipe with Variable Cross-Section
Authors: Guo Jun Qing , Yang Yong Shun , Chen Fu Xiao , Li Xue Kao
Published: November 2010

There are many advantages of magnesium alloy such as light mass, nonrattling and electromagnetic interference shield. Yet, its ductility was poor at room temperature and plastic forming was difficulty due to its close-packed hexagonal structure. In this paper, the superplasticity of magnesium alloy AZ91D was explored and the relationship between flow stress and true strain were achieved at different temperature by tensile tests. It was found that the flow stress of AZ91D as cast was less than 20MPa at 340-450°Cand superplastic deformation could be used to manufacture magnesium alloy parts. Utilized superplastic air bulking mold, AZ91D seamless pipes with variable cross-section were manufactured successfully based on process parameters being optimized. Moreover, the relationship between loading path of internal pressure and wall thickness was analyzed also.
Ethanol Vapor-Induced Morphology and Structure Change of Silk Fibroin Nanofibers
Authors: Fan Lin Peng , Cai Zeng Xiao , Wu Chun Chen , Geng Xiao Hua , Wang Hong Sheng , He Chuang Long , Mo Xiu Mei
Published: November 2010

In this study, regenerated silk fibroin (RSF, from Bombyx mori) nanofibers with smooth surface had been successfully prepared via electrospinning, as shown by SEM and then as-spun fibers were induced under 75% ethanol vapor. We aimed to investigate the morphology and structure change of 75% ethanol vapor-induced silk fibroin nanofibers. To determine any difference in surface topographies, the nanofibers were inspected using atomic force microscope (AFM) and the results showed that after inducement of 75% ethanol vapor for 24 h, the surface of fibers became rough. Differential Scanning Calorimetry (DSC) analysis indicated that electrospun SF nanofibrous membranes typically took silk I form and 75% ethanol vapor-induced SF nanofibrous membranes took silk II structure. These results suggested that 75% ethanol vapor inducement could be an attractive alternative to expand the application of RSF.
An Assessment of Low-Carbon Efficiency Evaluation in the Prospect of Environmental Optimization
Authors: Xi Xiu Yan , Li Jie
Published: November 2010

From the prospect of environmental optimization the paper establishes a two-dimensional structure of low-carbon efficiency model firstly, with which the different efficiency of economic development comes down to four models. Then the paper builds evaluation index system on low-carbon by taking the CCR model of DEA method as the main analysis approach. On the basis of the above the paper researches on the ecological economy efficiency of 7 economic regions in China from the three levels，namely economic growth efficiency, environmental optimization efficiency and low-carbon efficiency. Eventually, through index evaluation process on the development situation of the above-mentioned economic regions from 2006 and 2007 this article puts forward strategic development policy recommendations advices for the derived results.
Study of ITO Thin Film Deposited by RF Magnetron Sputter at Low Temperature
Authors: Lu Xiao Juan , Fan Duo Wang
Published: November 2010

ITO thin films used in PTCDA/Si detector should be made at low temperature for low temperature resistance of substrate. ITO thin films were deposited at low temperature by RF magnetron sputtering. Properties of ITO thin films such as conductivity and transmission measured by 4 point probe and UV spectral photometry respectively. The results show that the sputtering pressure is an important parameter in the deposition of indium tin oxide（ITO） thin films, which affects the properties of ITO films. The optimized parameter for preparation of ITO thin films at low temperature are sputtering pressure 0.45 Pa, sputtering power 45W. Meanwhile, the post-annealing is not necessary.
Permeability Prediction in the Impregnation Stage of Resin Transfer Moulding
Authors: Liu Zhuang , Wu Xiao Qing
Published: November 2010

The impregnation stage of the Resin Transfer Moulding process can be simulated by solving the Darcy equations on a mould model, with a ‘macro-scale’ finite element method. For every element, a local ‘meso-scale’ permeability must be determined, taking into account the local deformation of the textile reinforcement. This paper demonstrates that the meso-scale permeability can be computed efficiently and accurately by using meso-scale simulation tools. We discuss the speed and accuracy requirements dictated by the macro-scale simulations. We show that these requirements can be achieved for two meso-scale simulators, coupled with a geometrical textile reinforcement modeller. The first solver is based on a finite difference discretisation of the Stokes equations, the second uses an approximate model, based on a 2D simulation of the flow.
Hydrogen Dilution Influence on the SiC Films Preparation and Structural Properties as the Window Layer of p-i-n Solar Cell
Authors: Xu Bao Yu , Yang Hui Dong , Huang Bo , Shi Jun Dai
Published: November 2010

The SiC thin films as the window layer of p-i-n solar cell was prepared by PECVD technology in this article,investigated the influence of hydrogen dilution on the structure and optical properties of SiC thin films,found the optimal growth craft under the same conditions. The results showed that the optical band-gap of the window layer achieved the widest 2.2ev when hydrogen dilution rate was 6.25, furthermore, got inerratic surface morphology with deposition rate up to 0.1nm / s.
Forming Response of Ultra High Strength Steel Sheet to Stamping Speed during Hot Forming
Authors: Yu Hai Yan , Bao Li , Deng You Zhi , Cao Wei
Published: November 2010

Stamping speed is an important parameter in sheet metal forming especially in hot forming. In this study, hot forming of a U-shaped part made of ultra high strength boron steel (22MnB5) sheet is simulated with solid elements. The mechanical properties of 22MnB5 steel sheet and the key process parameters are introduced in detail. Emphasis is laid on the forming response of the boron steel sheet to stamping speeds of 3.25m/s, 0.325m/s and 0.0325m/s. The mechanism of stamping speed acting on hot formability and temperature field of the stamped part is analyzed. It is demonstrated that stamping speed affects both formability and the heat transferred from blank to tools and to environment during hot forming. And the coupling effect of material properties, the heat produced during plastic deformation and heat boundary condition decides the formability and temperature field. An appropriate stamping speed is more important for hot forming than that for common cold forming.
Calculation for the Acoustic Absorption Coefficient of Multilayered Materials by an Improved Extended Transfer Matrix Method
Authors: Yang Xue , Yu Wei Xiong , Yang Shen Lin , He Lin , Sun Jin Li
Published: November 2010

This paper describes an improved extended transfer matrix method to evaluate the acoustic absorption coefficient of multi-layered structure with viscoelactic materials for perpendicular incidence plane acoustic. Here, the dynamic behavior of viscoelastic materials is taken into account. By comparing the calculated and measured results, it is shown that the results calculated by the improved extended transfer matrix method are in good agreement with the results measured. This improved extended transfer matrix method can accurately estimate the sound properties of multilayered structures with viscoelastic materials.
The Stabilization of Central Wavelength of Fiber Bragg Gratings by Thermal Contraction Effect of Kovar Substrate
Authors: Wang Sheng Ching , Tsai Hsi Hsun
Published: November 2010

A stabilized laser is essential for optical fiber communication network. One of the passive technique for stabilization of central wavelength of laser is based on the application of fiber Bragg gratings. Due to the positive coefficient of thermal expansion of optical fiber, the Bragg gratings within the fiber written by excimer laser gives about 0.01nm/oC shift on the central wavelength respect to the ambient temperature which leads serious problem in the communication network. Since both the temperature and tension force are linearly proportional to the central wavelength of fiber Bragg gratings. A feasible approach to derive the wavelength stabilization is to decrease the tension force of fiber Bragg gratings respect to the increase of ambient temperature. In this paper, a Kovar substrate with negative coefficient of thermal expansion is used to decrease the tension force while the environmental temperature increases. The experimental results show that the coefficient of thermal expansion of the Kovar substrate is negative and linearly proportional to the temperature. Thus, this Kovar substrate differing from the constant negative coefficient of thermal expansion ceramic substrate induces about 0.0085nm/C on the fiber Bragg gratings, which shows the well application of this Kovar for athermalization of the fiber Bragg gratings in optical communication system.
A Microscopic Study on Local Strain Rate Sensitivity of Polypropylene Syntactic Foam with Microballoons
Authors: Wang En Yang , Omiya Masaki
Published: November 2010

A Microscopic Study on Local Strain Rate Sensitivity of Polypropylene Syntactic Foam with Microballoons
Preparation, Properties and Cytotoxicity Assessment of Nanosized Pt-Rh Composite Catalyst for the Decomposition of Gaseous Ammonia
Authors: Hung Chang Mao
Published: November 2010

The behavior of the ammonia (NH3) oxidation was by selective catalytic oxidation (SCO) over a nanosized Pt-Rh composite catalyst in a tubular fixed-bed flow quartz reactor (TFBR) at temperatures between 423 and 673 K. The catalysts surface properties were characterized using UV-Vis and TEM. The experimental results show high activities for NH3 removal was achieved during catalytic oxidation over the Pt-Rh catalyst at 673 K with an oxygen content of 4%. N2 was the main product in the NH3-SCO process over the nanosized Pt-Rh composite catalyst. These results also verify that the Pt-Rh metals on catalyst surfaces, resulting in the formation of the remarkable catalytically active sites at the metal-support interface in the reduction of NH3 in this process. In addition, the nanosized Pt-Rh composite-induced cytotoxicity testing was mainly applied to the human lung MRC-5 cell line and the percentage of cell survival was determined by MTS analysis in vitro. For nanosized Pt-Rh composite, only minor cytotoxicity was observed when human lung cells were exposed.
Preparation and Characterization of Polymethacrylimide Foam
Authors: Tang Hong Yan , Chen Long
Published: November 2010

A novel idea to prepare Polymethacrylimide (PMI) foam is presented in this paper, in which PMI foam was prepared by two steps, the butyl methacrylate (BMA)/methacrylamide (MAM) copolymer was formed using solution polymerization through free radical copolymerization, and then PMI foam was produced through the BMA/MAM copolymer foaming. Mechanism of polymerization reactions was analyzed. The BMA/MAM copolymer and PMI foam were investigated by Fourier transform infrared spectroscopy. It showed disappearance of the primary amide and appearance of the formation of PMI foam, which was in accordance with the mechanism of polymerization reactions. The polarizing micrograph showed PMI foam was highly transparent and closed cell. Differential scanning calorimetry and thermogravimetric analysis results showed PMI foam had excellent thermal stability below ~255°C because of the presence of the imide ring.
Study on the Matching between Cross-Linked Polymer Microspheres and Nuclear-Pore Membranes
Authors: Lin Mei Qin , Guo Jin Ru , Xu Feng Qiang , Zhang Gui Qing , Li Ming Yuan , Peng Bo
Published: November 2010

The shape and size of the linked polymer microspheres and the matching between the microsphere size and nuclear-pore membranes were studied in this paper. Scanning electron microscopy(SEM), microscope, dynamic lighting scattering(DLS), Laser diffracting measurements, nuclear-pore film filtration and sand packed tube displacement experiment was adopted for investigation. The results showed that the original shape of the microspheres is typically spherical with a size range of 400-5000nm. When the microspheres were dispersed in water, swelling occurred, resulting in larger size but spherical conformation remained. And the system was poly-dispersed. There are certain matching relationships between the microsphere size and the membranes pore size, and the best plugging property could only occur when they are well-matched. Matching relationships also exist in the sand packed tube displacement experiment, when sand packed tubes with low permeability were used, plugging could occur effectively, and well in-depth plugging could happen as well.
Composite Material of Concrete Meso-Failure Test
Authors: Zhao Ji Kun
Published: November 2010

With static and dynamic load for the research background, this paper conducted a four-phase composite model for concrete damage test simulation of micro-mechanics. The two kinds of three-point bending beam load ware studied in case of failure process. The study found that the location of the main crack in the most disadvantaged section of beam shear in the vicinity. Crack is always along the aggregate and the mortar bond zone be extended. The main crack extension direction is always toward the load point. The main crack is showing a tortuous shape. Dynamic load and static load the stress - strain curve is basically similar shape, but basically the same as the starting point of the initial fracture. Stress wave in the sample after multiple visits, is the main reason leading to the breakdown of the sample. Dynamic load cases, the concrete elastic modulus higher than the static modulus of elasticity, numerical simulation results agree well with the experimental results.
Characteristic of the High-Strength Magnesium Alloy on Cylinder Upsetting
Authors: Ruan Li Qun , Iguchi Yusuke , Usumoto Akira , Marumo Yasuo , Kawamura Yoshihito
Published: November 2010

The purpose of the present study is to evaluate the processing property of Mg96Zn2Y2 of casting material. Mg96Zn2Y2 is a high strength magnesium alloy material newly developed by Mr. Kawamura in Japan. The name of this alloy is called as 'Kumadai Goukin'. For this purpose, cylinder upsetting tests were performed. In addition, the marketing community of AZ31 magnesium alloy collates the information with the new material. We examined and compared the deformation resistance and ductility of the two materials. Furthermore, the dependence of deformation resistance and ductility of these materials to processing temperature and speed was evaluated [1].
Studies on Galling Behavior in Square Cup Drawing of High Tensile Strength Steel
Authors: Lin Qi Quan , Dong Wen Zheng , Wang Zhi Gang
Published: November 2010

In this study, galling behavior in macro-scale is investigated in the square cup drawing of a high tensile strength steel in semi-dry and dry condition on laboratory experiments. The drawing dies are set two types: the non-coated (SKD11, ADI and SLD) and coated (TiC and DLC-Si). When using the non-coated dies in semi-dry, the macro-scale galling can clearly observed on die and drawn cup surface after a few drawing cycles. As a result, the galling on the die surface occurs at the bottom point of the boundary between the straight and corner edge, and grows upward with the drawing cycles; on the drawn cup, the galling starts at the top of the same boundary and grows downward. Simultaneously, the finite element method (FEM) with DEFORM-3D was used to simulate the square cup drawing process with the respect to the drawing force distribution and volume change analysis, which gave us a rational interpretation of the galling phenomena and illustrated the galling behavior and seizing tumour theoretically. Furthermore, a continued experiment with coated dies for TiC (CVD) and DLC-Si (DC -PACVD) was carried out to seek a anti-galling tool material for the high tensile strength steel.
Investigation of Fabrication and Microstructure of the Fe3Al/Al2O3 Composites by Plasma Active Sintering Process
Authors: Jiang Tao
Published: November 2010

The Fe3Al/Al2O3 composites were fabricated by plasma active sintering process. The Fe3Al intermetallics compounds powders were fabricated by mechanical alloying and heat treatment. The Fe3Al intermetallics compounds powders and Al2O3 powders were mixed together, so the Fe3Al/Al2O3 composites were fabricated by plasma active sintering process at 1200oC for 5min under the pressure of 30MPa. The phase composition and microstructure of the Fe3Al intermetallics compounds powders produced by mechanical alloying and heat treatment were investigated. The phase composition and microstructure of the Fe3Al/Al2O3 composites produced by plasma active sintering process were investigated. The XRD patterns results showed that the Fe3Al intermetallics compounds powders were fabricated by mechanical alloying for 60h and heat treatment process. The XRD patterns results showed that there existed Fe3Al phase and Al2O3 phase in sintered composites. The microstructure showed that the mean particles size of the Fe3Al intermetallics compounds powders produced by mechanical alloying and heat treatment was about 4-5μm. The Fe3Al/Al2O3 composites exhibited the homogenous and compact microstructure. The mean particles size of Fe3Al was about 2-3μm and mean particles size of Al2O3 was about 2-3μm. The Fe3Al/Al2O3 composites exhibited homogenous and compact microstructure with the increase of Fe3Al content. The density and relative density of the Fe3Al/Al2O3 composites increased gradually with the increase of Fe3Al content.
Electroless Ni-P-SiO2 Composite Coatings and their Corrosion Behaviors in Simulated Furnace Flue Gas
Authors: Hou Feng , Xu Hong , Dai Yu Lin , Yao Zhi Yan , Yan Cao
Published: November 2010

Over the last ten years, sulfuric acid dewpoint corrosion has become a more important concern in refinery furnaces since sulfur levels in fuels have increased. Electroless nickel phosphorous coating is one of the most widely used industrial coatings owing to its good corrosion resistance in many highly corrosive environments. In this work, electroless Ni-P-SiO2 composite coatings were prepared on AISI 1020 carbon steel. And the corrosion behaviors of Ni-P-SiO2, Ni-P coatings and carbon steel substrate were evaluated by immersion, electrochemical tests in 5%wt sulfuric acid solution, and dewpoint corrosion tests in simulated furnace flue gas. The experimental results indicated that corrosion resistance properties of Ni-P-SiO2 coating was best, followed by Ni-P coating and carbon steel was worst.
Effect of Al and ZrO2 on Sinterability and Mechanical Properties of B4C
Authors: Lin Wen Song , He Liang
Published: November 2010

Ceramics composites of B4C matrix with 5 wt% Al and various amount of ZrO2 additives were pressureless sintered under vacuum at 2250 °C for 60 min. Density, hardness, flexural strength and microstructure of the specimens were measured and characterized. Densities above 97% theoretical density (TD) were determined in the samples prepared with the addition of 8 wt% ZrO2 and 5 wt% Al, compared to 86% TD for single-phase B4C. X-ray diffraction analysis showed that B2O3 (impurity in B4C) was eliminated and new phases (ZrB2 and B4C1-x) were formed in the sintered samples, suggesting that in situ reactions between B4C/B2O3 and Al/ZrO2 happened during sintering process. It was showed that the elimination of B2O3 and the forming of boron rich solution of B4C1-x significantly improved the sinterability of B4C matrix ceramics, and consequently enhanced the densification rate greatly. The flexural strength and Vickers hardness of the sintered samples with addition of 8 wt% ZrO2 and 5 wt% Aluminum reached the value of 560 MPa and 30.2 GPa respectively, much higher than those of single-phase B4C ceramics.
Microstructural Evolution and Weldability of AISI 4042 Steel
Authors: Gulenc Behcet , Uygur Ilyas , Bayram Ismail , Durgutlu Ahmet , Kap Tuncay
Published: November 2010

High carbon content and addition of other elements, such as Mn in steel, causes some difficulties in the weldability of these materials. In this study, pre and post heating processes were applied for the multipass welded specimens. Tensile test, notch impact test and hardness measurements were carried out, and microstructural features were examined. The weldability of these steels can be improved with the pre and post heat treatments. Maximum hardness values were obtained for the non-heat treated specimens due to large grain structure and high volume percentage of the pearlite content. Although applied heat treatments caused decrease in hardness values, an increase in tensile properties and toughness values at all temperatures occurred. Changes in these properties were explained in the light of the microstructure of the AISI 4042 steel specimens.
Coupling Capillary Electrophoresis and Ion Mobility Spectrometry via Electrospray Interface: a Preliminary Study
Authors: Jiang Xue Mei , Svensmark Bo , Deng Lin Hong
Published: November 2010

To combine capillary electrophoresis (CE) and ion mobility spectrometry (IMS) to setup CE-IMS coupling technique, an effective sheathless electrospray interface was developed in the paper. The capillary was rotated on a fixed connector and tapered by manual gridding on the emery paper to obtain tapered capillary tip with the polyimided layer, geometric symmetry. And then the tapered tip was coated with nickel by a simple electrode-less plating procedure to be electrically conductively, so as to generate the electrospray on the tip. Finanlly, three different ways were evaluated for coupling CE with IMS, and get the relatively more effective interface to combine CE and IMS.
Synthesis and Electrochemical Properties of LiFe0.95Ti0.05Po4/(C+LiFeP2O7) Composite Material
Authors: Chen Zhao Yong , Zhang Jian Li , Zhu Hua Li , Zhu Wei , Li Qi Feng
Published: November 2010

A new LiFePO4-based phase composite LiFe0.95Ti0.05PO4/(C+LiFeP2O7)was synthesized by solid state method . The amorphous carbon and phosphate LiFeP2O7 consisted of the protective layer and coated the surface of the solid solution LiFe0.95Ti0.05PO4 The phosphate LiFeP2O7 was detected though XRD(X-ray diffraction)and CV(cyclic voltammetry).Morphology of the composite was observed by scanning electron microscope(SEM)and Transmission electron microscopy (TEM), it illustrated Ti4+ had been induced into the crystal lattice of LiFePO4 and formed the solid solution LiFe0.95Ti0.05PO4.The data of charge-discharge tests showed the composite had excellent electrochemical properties. Initial charge and discharge capacity of LiFe0.95Ti0.05PO4/(C+LiFeP2O7) had reached 157.9mAh/g and 155.2mAh/g at the rate of 0.1 C, respectively. At 1C, the discharge capacity of the composite remained 125mAh/g after 100 cycles.
Effect of Concentration on Electrospinning Oil Sorptive Fiber
Authors: Liu Yan Ping , Xu Hua Bin , Deng Yi Bing
Published: November 2010

Electrospinning is a convenient method used in the preparation of ultrafine oil sorptive fibers based on Ethylene-propylene-diene (EPDM), Electrospun fiber diameter, varying in large from micrometer to nanometer, mainly depends upon the solution concentration, which has great influence on this function fiber’s sorption ability. The non-linear relation between mean fiber diameter (d) and solution concentration (C) was investigated and it follows a simple scaling law in the form . This relationship can be used to predict the target fiber diameter and guide the processing technique. The effects of various C on oil sorption ability were investigated in a batch-sorption technique. A comparison of the kinetic models, showed that the removal rate fit the first order kinetic model well, which suggested the sorption process is rapid, can reach equilibrium within a short time.
An Experimental Investigation of the Shell-Side Pressure Drop of Enlarged-Hole Whole-Rounded Baffle Heat Exchanger
Authors: Sun Hai Yang , Qian Cai Fu
Published: November 2010

In this paper, the flow characteristics of the whole-rounded enlarged-hole baffle heat exchangers are experimentally studied with the stress on the shell-side pressure drops. It is found that the shell-side pressure drops for the whole-rounded baffles with the enlarged holes are greatly decreased. Compared with the square layout, the enlarged-hole whole-rounded baffles in the case of triangle layout is even more effective in decreasing the pressure drop. The shell-side pressure drops for the heat exchangers with the enlarged-hole whole-rounded baffles are proportional to the square of the flow rate.
Experimental Studies on Thermal Strain of Aerial Laminated Glasses
Authors: Han Wen Mei , Kang Tian He , Xue Chun Xia
Published: November 2010

Experimental studies on thermal strain of aerial laminated glasses by virtue of Moire Interferometry were done. The experimental results were as follows: in the U patterns of moire interference fringe, with temperature increasing, the fringes became denser and the thermal strain was augmented. In the V patterns of moire interference fringe, the sequence of the fringe patterns increased is intermediate film layer, external shielding layer and main bearing layer, respectively. The U and V fringe patterns results analyzed by digital image process system indicate that, with temperature increasing, the strain εx decreased. Because the difference of coefficients of thermal expansion of three materials is very large, the thermal strain is generated significantly, and the interlayer thermal shear strain exists in the end and intermediate position of the free boundary of the laminated glass.
Modeling and Simulation Analysis of the Twist Drill Conical Grinding Method Based on Pro/E Software
Authors: Gao Xing Jun , Liu Qing , Zou Ping , Song Jian , Li Ping
Published: November 2010

The fundamental principle of the twist drill conical grinding method was introduced. The mathematical model of the twist drill was established. Mathematical model to establish drill bit is the geometric design, manufacture, cutting analysis and modeling on the basis of the drilling process. According to the twist drill grinding principle, using Pro/E the three-dimensional modeling of the twist drill was completed, and the feature of the conical grinding method was analyzed.
Supercapacitor from Nitrogen-Doped Carbon Nanotubes
Authors: Li Li Xiang , Liu Yong Chang , Gen Xin , An Bai Gang
Published: November 2010

CNTs were treated with hydrazine hydrate and diethylenetriamine, respectively. Scanning electron spectroscopy (SEM) observation showed that the doped CNTs kept the length/diameter ratio of pristine CNTs. X-ray photoelectron spectroscopy (XPS) characterized that nitrogen can be doped to CNTs. XPS analysis further indicated that C/N atomic ratio of CNTs treated by hydrazine hydrate is 95/2, four times of CNTs treated by diethylenetriamine, which is 96/0.5. The hydrophilicity for N-doped CNTs (N-CNTs) is much improved and enhanced by increasing N proportion. As electrode material of supercapacitor, nitrogen functional groups contribute pseudo-Faradic capacitance, but its cyclic performance still need to be improved. Thanks to the good hydrophilicity for N-CNTs that improves the wettability of CNTs for electrolyte; the specific capacitance of N-CNTs is still slightly higher than pristine CNTs after cycling.
Synthesis of Chitosan Grafted Ternary Polymerization
Authors: Wang Yu Jie , Xue Juan Qin , Mao Wei Bo , Wu Ming , Li Jing Xian
Published: November 2010

In this study, the graft copolymerization of acryalmide and acrylonitrile onto chitosan with K2S2O8-NaHSO3 initiator under N2 interaction is studied and the mechanism is discussed. Compared to the chitosan graft of acrylamide or acrylonitrile, the graft yield and graft efficiency of ternary polymerization increase significantly. The stability and reproducibility are also improved obviously. To be specific, the reaction time, the reaction temperature, the effect of the amount of materials, the concentration of K2S2O8, and the concentration of NaHSO3 on the graft yield and graft efficiency is investigated respectively. The C=C of acrylamide and the acrylonitrile react respectively with -NH2 and C6-OH of chitosan initiated by SO4-•. The experimental results show that the optimal synthesis conditions are given as follows: the reaction time is 6h, the reaction temperature is 60°C, the ratio of m(chitosan):m(acrylamide):m(acrylonitrile) is 1:7:5, the concentration of K2S2O8 is 4.5mmol/L, and the concentration of NaHSO3 is about 2.6mmol/L. Under such conditions the graft yield and graft efficiency can be up to 839.52% and 70.00%, respectively.
Theoretical Studies on the Chemical Structure of Carboxymethyl Chitosan
Authors: Lu Xi , Xue Juan Qin , Wang Yu Jie , Mao Wei Bo , Wu Ming , Li Jing Xian
Published: November 2010

The density functional theory (DFT) calculations explored the structural optimization and the frequency of N-carboxymethyl chitosan (N-CMCS) and O-carboxymethyl chitosan (O-CMCS). For the isomers, the calculations comparatively were performed. The charge distribution and frontier molecular orbit were analyzed by using the natural bond orbital (NBO) method. The results showed: the two rotational isomers a and b can stably exist, with the stability order a>b; N-carboxymethyl chitosan reaction active sites are concentrated in -OH and -NHCH2COOH, while O-carboxymethyl chitosan reaction active sites are concentrated in -NH2 and -CH2COOH; The water-soluble mechanism of carboxymethyl chitosan was investigated deeply, on the one hand, the presence of carboxymethyl of carboxymethyl chitosan had a tendency to ionize H+, on the other hand the carboxymethyl increased the distance and weakened the hydrogen bonds between molecules, even though Einstein shift H-bond is formed in the carboxymethyl chitosan molecules.
Microstructure and Mechanical Properties of Molybdenum Alloys Doped with ZrB2 Particles
Authors: Zhang Guo Jun , Zhuo Jun , Ren Shu Ai
Published: November 2010

The molybdenum alloys doped with various mass fraction zirconium diboride (ZrB2) particles were successfully prepared by using the powder metallurgy technology. The microstructure, hardness and the tensile properties of the pure molybdenum and molybdenum alloys doped with ZrB2 particles were determined at room temperature. Results showed that the addition of zirconium diboride refined the molybdenum grains obviously, meanwhile, molybdenum grain sizes decrease with the increasing of zirconium diboride mass fraction. Measurements on mechanical properties showed that molybdenum alloys doped with ZrB2 particles had higher hardness and strength than pure molybdenum. The analysis and discussion results show that the strengthening mechanisms of ZrB2-doped molybdenum alloys may be attributed to the fine-grain strengthening, particle dispersion strengthening, interfacial-bond strengthening and oxygen reduction strengthening.
Microstructure and Corrosion Resistance Behavior of Composite Micro-Arc Oxidation and Sio2 Coatings on Magnesium Alloys
Authors: Ge Yan Feng , Jiang Bai Ling , Yang Zhi Yuan , Li Yu Lei
Published: November 2010

SiO2 sol sealing agent was developed by hydrolyzing of organic alkoxide, and protective composite coatings were obtained on magnesium alloys AZ31B by micro-arc oxidation (MAO) treatment plus a top coating with sealing agent using dipping-costing technique. SEM observations revealed that SiO2 sol immersed into pores and uniformly covered the surface of MAO coating. XPS analysis indicated that an inorganic SiO2 layer has formed on the surface of MAO coating. The results of potentiodynamic polarization tests showed that corrosion resistance of AZ31B alloys with composite coatings was evidently superior to that of merely MAO coating. The SiO2 layer provided corrosion protection by physically sealing the pores on the MAO coating and acting as a barrier. The composite coatings could suppress the corrosion process by preventing the transferring or diffusing of corrosive ions between magnesium alloys substrate and solution.
The Strength of Vacuum-Free Diffusion Bonding Joints of Ni-Bi Alloys and ZrO2 Ceramic
Authors: Pan Hou Hong , Wang Ke Jun , Itoh Isao
Published: November 2010

Ni-Bi alloys were selected to bond to ZrO2 ceramic by diffusion bonding at atmosphere for researching their bondability. The Ni-Bi alloys were Ni-xmass%Bi (x=0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0) and ZrO2 ceramic was Z201N. The bonding was carried out at 973 K, 1037 K and 1173 K for 3.6 ks, 5.4 ks, 7.2 ks, 9.0 ks and10.8 ks under the pressure of 2 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa and 12 MPa. The bonding strength was examined by the shear fracture test from room temperature to high temperature. The results indicate that pure nickel could be bonded to ZrO2. Adding bismuth into nickel alloy could obviously improved shear strength at room temperature. The optimum content of bismuth was 2%. The shear strength of vacuum-free diffusion bonding joint was higher than that of vacuum diffusion bonding joint. ZrO2/Ni-2Bi joint was bonded at 1173 K for 7.2 ks under 8 MPa, which shear strength was up to 22 MPa until the test temperature of 873 K.
Influences and Mechanisms of Ordinary Portland Cement on Properties of Asphalt Emulsion Composites
Authors: Wang Zhen Jun , Wang Rui
Published: November 2010

Asphalt emulsion composites are energy-saving, ecologically safe materials because they do not need any heating processes which can emit gas and fire hazard in their use. Their use for highway structural layers has attracted relatively little attention largely in China because of the problems associated with the time taken for full strength to be achieved after paving and the susceptibility to early life damage by rainfall. This research work aims at studying influences of using ordinary Portland cement to asphalt emulsion composites. The asphalt emulsion composites were prepared using a three step; road properties were studied and mechanisms were analyzed with Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Analysis (EDXA). The results indicate that ordinary Portland cement addition improves road properties of the composites, such as Marshall stability, compressive strength, dynamic stability and ratio of splitting strength after freezing-thawing cycles. Splitting strength at low temperature of the composites increases with the cement increase, but if the cement dosage surpasses 3.0%, the composites become brittle. So optimal cement dosage is 3.0% in aggregate mass. There is much hydrated calcium silicate(C-S-H) gel in the composites with the cement, which can increase mass and atom percentage of Ca element and Si element, decrease proportions of free asphalt and make mastics in the composites more dense. Road properties of asphalt emulsion composites can be improved.
Tensile Ductility of Ultra-Fine Grained Copper at High Strain Rate
Authors: Suo Tao , Xie Kui , Li Yu Long , Zhao Feng , Deng Qiong
Published: November 2010

In this paper, ultra-fine grained copper fabricated by equal channel angular pressing method and annealed coarse grained copper were tensioned under both quasi-static and dynamic loading conditions using an electronic universal testing machine and the split Hopkinson tension bar respectively. The rapture surface of specimen was also observed via a Scanning Electron Microscope (SEM). The experimental results show that the ductility of polycrystalline copper decreases remarkably due to the grain refinement. However, with the increase of applied strain rate, ductility of the UFG-Cu is enhanced. The fracture morphologies also give the evidence of enhanced ductility of UFG-Cu at high strain rate. It is believed the enhanced ductility of UFG materials at high strain rate can be attributed to the restrained dislocation dynamic recovery.