bluuebunny/crossref_metadata_2025 huggingface dataset:
Diethylenetriamine-Assisted Hydrothermal Route to Synthesize Cuboidal Structure of PbSe Crystal
Authors: Xiao Pei Pei , Xue Fei , Wang Ting Ting , Qian Yi Tai
Published: September 2009

With the assistance of diethylenetriamine(DETA), well-crystalline PbSe cuboidal structures with different concave faces in each plane have been successfully prepared through a hydrothermal process using Na2SeO3 as selenium source at 180 °C for 48 h. The products have been characterized by means of X-ray diffraction, field-emission scanning electron microscopy and luminescence spectroscopy. The field emission scanning electron microscopy showed that the edge lengths of these cuboidal crystals ranged from 1.5 to 2.5 µm, and the edges of a cube crystal extend outwards from its core with a tiny cubic center leaving step-like faces. The shape evolution of PbSe crystal from eight-dendritic structure to cuboidal structure was observed and the possible growth mechanism was proposed. Results revealed that the temperature played a crucial role in the final morphology of PbSe microstructures, and other factors such as the solvent composition and the molar ratio of metal/chalcogen were also discussed. The photoluminescence (PL) spectrum of as-prepared PbSe crystals shows the photoluminescence emission spectrum consists of a main intense peak at 435 nm and a shoulder at 420 nm. This synthesis method could be extended to the morphogenesis of other inorganic crystals with complex forms.
Microstructure and Mechanical Property of 2.5D C/SiCN Composite
Authors: Xia Yi , Qiao Sheng Ru , Wang Qiang Qiang , Zhang Cheng Yu
Published: September 2009

Carbon fiber reinforced silicon carbonitride ceramic composite (C/SiCN) was prepared by rapid electro-thermal pyrolysis chemical vapor deposition using liquid hexamethyldisilazane as precursor. The density of C/SiCN is 1.75g/cm3 and with 15% porosity. Microstructure characteristics of C/SiCN were examined by transmission electron microscopy and scanning electron microscope equipped with energy dispersive spectrometer. The mechanical properties were characterized by three-point bending test. Microstructure observation displays a high degree of coalescence between SiCN matrix and fiber filaments, but there also exist plenty of micro-pores within fiber bundle. It is different from that of C/SiC composite made by chemical vapor infiltration. Mechanical test exhibits a mostly obvious nonlinear fracture behavior, which can be explained by typical toughening mechanism of long fiber-reinforced ceramic matrix composite.
NiCr Electrically Conductive Coatings on Cotton Fabric by Electron Beam Evaporated Deposition
Authors: Li Feng Yan , Zhong Zhi Li
Published: September 2009

The 80Ni20Cr coatings on cotton fabric substrates using the electron beam evaporated deposition are reported to improve the electrical conductivity of fabric substrates. The cotton fabrics are coated twice for single-faced NiCr film and one time per face for double-faced NiCr film, respectively. The morphology of coatings is characterized by an optical microscopy. The effect of sample length and test orientation of warp-wise and weft-wise on electrical conductivity is measured. It is found that the NiCr coatings dramatically increase the electrical conductivity of cotton fabrics. For warp-wise orientation with lengthwidth (4 cm1 cm) of test sample, the surface resistance is about 0.7 MΩ for single-faced coating and 0.89 MΩ for double-faced coating, while the surface resistance of raw cotton fabric is above 104 MΩ. The results tested from warp-wise and weft-wise are uniform, which is mainly because of the structure balance of the plain fabrics. The microstructure observation indicates that the single-faced coatings are uniform and dense, and the present double-faced coating processes are not enough to completely cover the fabric substrates. The uniform and dense coatings of single-faced NiCr coatings could be the reason that the electrical conductivity is better than that of the present double-faced NiCr coating.
Effect of Cold Rolling Deformation on Aging Precipitation of Cu-Cr-Sn-Zn Alloy
Authors: Su Juan Hua , Jia Shu Guo , Ren Feng Zhang , Liu Ping , Tian Bao Hong
Published: September 2009

The effects of different extent of cold rolling on the aging properties in Cu-Cr-Sn-Zn alloy are investigated by hardness and electrical conductivity analysis and microstructure TME (transmission electron microscopy) observation of the alloy. The results shows that dislocations provide nucleation site for precipitation during aging treatment, and result in the precipitation hardening effect from a finer size of precipitates. At 60% ratio of cold rolling and aged at 450°Cfor 1h, the hardness and electrical conductivity can reach 171.3HV and 71.5%IACS respectively.
A Green Approach to Preparing Nanosized Hollow Silica Microspheres with Waste Polystyrene
Authors: Wang Hong Feng , Wang Zhi Qi , Wang Ai Ping , Zhu Zhi Bin , Yin Yan Sheng
Published: September 2009

An attempt was made to prepare hollow silica microspheres by an oil-in-water emulsion which proposed to use waste polystyrene organic solution as oil phase. Effects of the kinds and amounts of surfactants and the concentration of waste polystyrene solution on the nanosized hollow silica microspheres were studied. The prepared hollow silica microspheres were characterized by TEM, XRD, TG-DTA and particle size distribution analyzer. The experimental results showed that the waste polystyrene organic solution was successfully treated as oil core and the cores could be removed at about 350°C. Meanwhile, the obtained hollow microspheres were amorphous with an average particle size of 40nm. The hollow silica microspheres could be obtained with the selected surfactant.
Preparation, Cytotoxicity and Degradability of Chitosan-Based Thermosensitive Hydrogels as Drug Delivery System
Authors: Zhou Hui Yun , Wang Jian , Zhang Wei Fen , Wang Ye , Chen Xi Guang
Published: September 2009

A new thermosensitive hydrogel had been prepared that could be transformed into gel at 37 °C from chitosan and a mixture of α- and β-glycerophosphate (αβ-GP). The appearance of hydrogel was compact and corrugated. There was little granule in the appearance of gel loaded with adriamycin and the granules might be crystals of the added model drug. In vitro cytotoxicity of the hydrogel was tested by the MTT method using mouse embryonic fibroblasts (MEF). MEF cultured with leachates of CS-αβ-GP were investigated and the relative growth rate (RGR) was calculated and the cytotoxicity was graded by generally accepted standard. The study of in vitro degradation of CS-αβ-GP hydrogels included hydrolysis and degradation by lysozyme. The CS-αβ-GP thermosensitive hydrogel was degradable in vitro and the degradation rate was faster in lysozyme solution than that in the medium of PBS. So the CS-αβ-GP system had good cell biocompatibility and biodegradability which provided possibilities and foundations for the further research.
Heterogeneous Preparation of Polyaniline-Cellulose Conductive Composites with Cellulose Pretreated by Ultrasonic and its Electrical Properties
Authors: Zhao Zhong Li , Mo Zun Li , Feng Chao , Wang Jun
Published: September 2009

A series of conductive composites polyaniline(PANI)-cellulose were heterogeneously synthesized by chemical oxidative polymerization of aniline with native cellulose pretreated by ultrasonic. The morphology and chemical structure of the composites were examined by SEM and FTIR. TGA was used to study their thermal properties. The electrical conductivity was measured at room temperature by the standard four-probe method. For the sake of illuminating the influence of ultrasonic pretreatment on the structure and properties of PANI-cellulose composites, the SEM microphotographs, FTIR spectrum and TG curve of the PANI-cellulose composites prepared with native cellulose without any treatment were also shown in this paper to serve as reference. The PANI content and electrical conductivity of these two composites were also compared. It was found that cellulose surface was severely eroded by ultrasonic wave, and PANI homogeneously dispersed on this eroded cellulose surface in the form of particles. In reverse, the PANI particles loaded on the surface of untreated cellulose with evident aggregation. The homogeneous dispersion of PANI particles would be favor for the improvement of the electrical conductivity of the composites. From the FTIR spectra, it was verified that there was no difference between these two composites. It indicated that ultrasonic force did not lead to the variation of the chemical structure of cellulose. TG curves revealed that the thermal stability of PANI-cellulose composites was obviously enhanced than pure cellulose due to the protection of PANI particles deposited on its surface. Nevertheless, ultrasonic has a negative effect on the thermal stability of the composites, which resulted in the long cellulose molecular chains change into shorter ones, so the decomposition of composite occurred at lower temperature. It was because that ultrasonic pretreatment contributed to the homogeneous dispersion of PANI and more PANI particle depositing on the cellulose surface. Therefore, the PANI-cellulose composites with ultrasonic pretreated cellulose have more PANI content and higher electrical conductivity than the composites with untreated cellulose. Moreover, the difference of these two factors between the two composites became more and more marked with increasing of the amount of aniline. When aniline used was up to 0.5 g, the PANI content in the former was 48.2% more than the latter. This work provided a facile method for the synthesis of PANI-cellulose conductive composites with excellent conductivity.
Synthesis and Characterizations of Cubic Assembly Composed of Platinum Nanoparticles
Authors: Yang Ming , Yang Xiao , Ma Jing , Zhang Kai Cheng
Published: September 2009

Cubic assembly composed of platinum nanoparticles has been prepared by a simple reaction between H2PtCl6•6H2O, NaOH and NaBH4 in the presence of deionized gelatin. Gelatin played a decisive role as an inhibitor of the direct reaction of NaBH4 with H2PtCl6•6H2O and coagulation of the growing platinum in producing the cubic assembly composed. In the absence of gelatin, we can only obtain irregular large platinum particles. With decreasing the temperature, the viscosity of the solution increased. The diffusions of BH4- ions and PtCl62− ions are slower. The assembly composed of platinum nanoparticles was synthesized at 10 oC. The products were characterized by X-ray powder diffraction, scanning electron microscope, X-ray photoelectron spectra and UV-visible absorption spectroscopy. The scanning electron microscope images show the as prepared platinum with cubes and the average dimensions is about 0.35-0.45 μm. The UV-visible absorption spectrum of the as prepared platinum particles dispersed in ethanol solution shows one absorption peaks at 215nm. The size of the subunits of the polycrystalline platinum particles was calculated to be about 4 nm according to half width of the diffraction peaks using Debye–Scherer equation.
Mechanism Researches on the Mutual Adaptability and the Dispersivity and Stability of Nanoparticle-Modified Asphalt Composite
Authors: Zhang Jin Sheng , Li Jia , Shi Rui Xia , Pang Lai Xue
Published: September 2009

The study of nanoparticle-modified asphalt is an intense popular interest and also a heading issue of transportation materials. To make the most of excellent properties of nanoparticle-modified asphalt, the mutual adaptability between the additive and asphalt as well as the dispersive stability in nanoparticles-modified asphalt system must considered at the first. In this paper, the basic principle of nanoparticles-modified asphalt is introduced. The mutual adaptability between the additive and asphalt as well as the dispersive stability in nanoparticles-modified asphalt system is studied. In addition, emulsified nanoparticles-modified asphalt and other issues are presented briefly.
Notched Strength Prediction and Verification of APC-2 Composite Laminates at Elevated Temperature
Authors: Jen Ming Hwa R. , Sung Yi Chun , Tseng Yu Chung
Published: September 2009

The notched strength of AS-4/PEEK (APC-2) composite laminates with a central hole at elevated temperature was systematically studied by both analytical and empirical methods. First, the APC-2 cross-ply [0/90]4s panels were fabricated and cut into samples. Each sample was drilled a hole in the center with five kinds of diameters, such as d=0(unnotched), 1, 2, 3, and 4mm. Then, the samples were subjected to quasi-static tensile tests at elevated temperatures, including 25°C (RT), 75, 100, 125, 150 and 175°C, to measure their mechanical properties. The average values of received notched strength were affected significantly by stress concentration and high temperature. In analysis the prediction of residual strength by point stress criterion (PSC) was adopted first and found unsatisfactory due to at least 15% errors with experimental data. Then, the modified PSC was used with the varied characteristic length dependent on nature of material and specimen geometry. The predicted notched strengths by the modified PSC model were in very good agreement with experimental data. The predictive results were not only precisely validated, but extended to the application at elevated temperature.
Characterization of Wear Performance of Micro-Plasma Surface Hardened Layer
Authors: Liu Gu , Chen Gui Ming , Wang Liu Ying , Hua Shao Chun , Yao Jian Xun
Published: September 2009

Samples of AISI 1045 carbon steel were surface hardened by micro plasma transferred arc (PTA) process. The hardened layer was characterized using both light optical and scanning electron microscopy and microhardness techniques. The tribological properties of the surface hardened layer and untreated substrate were investigated using a block-on-ring tribometer sliding against GCr15 steel under unlubricated condition. The worn surface morphologies and dominant wear mechanisms were identified using microscopy techniques. Results show that the surface hardened layer consists mainly of martensite and retained austensite with fine and dense structure, the microhardness of hardened layer increases from approximately HV 200 to HV 600. The wear volume loss of plasma hardened layer was 81.86×10-11m3 much better than that of untreated AISI 1045 carbon steel (743.44×10-11m3). Wear of untreated AISI 1045 carbon steel occurred by combined mechanisms of adhesion, abrasion and plastic deformation. While the worn surface of surface hardened layer is quite better with slight track and thin oxides on the worn surfaces. Plasma surface hardening has essentially changed the wear mechanism of the AISI 1045 carbon steel to slight abrasion and oxidation wear.
Synthesis and Characterization of Highly Branched Poly(urethane-imide)s
Authors: Chen Wen Qiu , Yi Chang Feng , Xu Zu Shun
Published: September 2009

A series of novel highly branched poly(urethane-imide)s (PUIs) were first successfully prep-
ared by a two-step method with toluene-2,4-diisocyanate (TDI), pentaerythritol (PAT) and dianhydrides, including pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-oxydiphthalic anhydride (ODPA). It was found that the prepolymerization of PAT and TDI at 40 °C was ascertained to be 40 minutes. And the imidization of the prepolymer and PMDA was successfuly carried out after 120 °C for 2 hours. The XRD demonstrated that the obtained highly branched PUIs pre-
sented semicrystalline aggregation structure which had clear crystal phase with the d-spacing around 0.39 nm. TGA curves exhibited that these highly branched PUIs had obviously two steps of weight loss attributed to the urethane chain segment and imide chain segment, respectively. The solubility testing indicated that the highly branched PUIs exhibited desirable solubility in various polar aprotic solvents, and were also resistant to dilute acid corrosion.
Morphology of Electrospun Natural Rubber with Acrylonitrile-Butadiene-Styrene
Authors: Sithornkul Sarawuth , Threepopnatkul Poonsub
Published: September 2009

This research was aimed to study the electrospinning of natural rubber (NR)-acrylonitrile butadiene styrene (ABS) blend. The NR used in this research was compounded in a torque rheometor, with stearic acid, wingstay-L, dibenzothiazoledisulfide (MBTS), tetramethylthiuram disulfide (TMTD) and sulfur, respectively. The compounded NR was blended with ABS by dissolving them in tetrahydrofuran (THF), concentration of solution included 5, 10, and 15 w/w%. The ratio of NR/ABS was varied by varying the content of ABS of 20, 30, 40 and 50 wt%. Then NR/ABS electrospun membrane was built up by electrospinning technique with high voltage 15 kV, flow rate 30 ml/h, collector distance 15, 20 and 25 cm and collected the electrospun fiber on rotating circular at 1000 rpm. The morphology of electrospun fibers were characterized by scanning electron microscope (SEM). SEM images showed that NR/ABS membranes had higher porosity with decreasing ABS contents. Decreasing ABS contents, decreasing solution concentration and increasing collector distance decreased fiber diameter of electrospun NR/ABS.
Bending Characteristics of Electrical Responsive Poly(vinyl alcohol)/Poly(acrylic acid) Semi-Interpenetrating Polymer Network Hydrogel under DC Electric Field
Authors: Cui Wei Wei , Liu Li Zhu , Zhu Xing Song
Published: September 2009

Semi-Interpenetrating networks (SIPN) hydrogel composed of poly (acrylic acid) (PAA) and poly (vinyl alcohol) (PVA) was prepared by free radical solution polymerization. The SIPN was characterized by Fourier transform infrared spectroscopy (FTIR). The electric stimuli responsive characteristics were investigated. The hydrogel bent toward the anode initially, altered the bending direction for two times and bent toward the anode ultimately when it was placed in a 0.1 M NaCl aqueous solution under non-contact DC field. For interpreting the special deformation the osmotic pressure curves according to Shiga’ osmotic pressure model were simulated and the pH gradient theory was applied to explain the final direction.
Mechanical Properties and Applications of CFRP in Retrofitting and Repairing Reinforced Concrete Short Columns
Authors: Wang Wei , Cai Xin Jiang , Tian Shi Zhu
Published: September 2009

The mechanical properties of CFRP without epoxy resin were tested by the monotonic load method, and the corresponding stress-strain relationship curve was established. The probability model and the parameter fitting based on Weibull distribution theory were applied, and the characteristic strength parameter and the shape parameter of CFRP were obtained. Three large scale RC short columns were constructed, the specimen not retrofitted, specimen strengthen retrofitted by CFRP and specimen repaired by CFRP which has been damaged by earthquake were simulated respectively. Quasi-static testing was carried out. The hysteretic-loop curve and average framework curve were obtained, furthermore, the performance of ductility and strength were analyzed and compared. The calculational results approximately agree with the experimental results, which prove the validity of OpenSees. The short columns retrofitted by CFRP have superior ductility so as to enhance the seismic performances effectively. The residual seismic behavior of short columns can also meet the requirement of seismic code. The research provides reference to seismic analysis and engineering design of retrofitted reinforcement concrete structures.
Preparation and Properties Analysis of Polyaniline/Nano-SrFe12O19 Composites with Different Morphologies
Authors: Li Qiao Ling , Zhang Cun Rui , Ye Yun
Published: September 2009

Polyaniline/nano-SrFe12O19 composites were prepared by in situ polymerization method for the first time. Rod-like and flower-like morphologies composites were synthesized in the phase of an emulsion polymerization system. It was found that the morphology of obtained PANI/nano-SrFe12O19 composites depended on the content of SrFe12O19 of the reaction system. A possible mechanism for the formation of the different morphologic composites had been proposed. The magnetic properties of the PANI/nano- SrFe12O19 composites were inspected by VSM. The possible mechanism for magnetic variation had been proposed in the paper.
Microstructure and Properties of Ti-Al Based Composite Coating Prepared by Electrospark Deposition Process
Authors: Guo Feng , Su Xun Jia , Li Ping , Hou Gen Liang , Mei Zhen Xing
Published: September 2009

Ti-Al based composite coating was fabricated on LY12 aluminum alloy surface by electrospark deposition (ESD) process, with γ-TiAl as electrode. The microstructural characteristics, element distribution, microhardness and wear resistance of the coating were investigated. The results show that the coating forms metallurgical bonding to the substrate, which consists of strengthened layer, transition layer and heat affected zone. Besides the Al phase, the coating is also composed of Ti-Al intermetallic compounds and a small mount of Ti/Al oxides and nitrides. The microhardness of composite coating decreases gradually along the depth direction. The sliding wear test results suggest that the worn volume loss of the coating is less than one third of that of the substrate. The abradability of LY12 aluminum alloy is significantly improved. The phases with higher hardness dispersed in the coating increase not only composite coating hardness but also the resistance to micro-cutting and plowing during the sliding wear test. In addition, the excellent sliding wear resistance of composite coating is also related to the metallurgical bonding between the coating and the substrate.
Effect of Pore-Forming Agents on Structure and Properties of PVDF/PVC Blend Membranes
Authors: Shen Hui Ling , Bai Lu , Liao Hua , Xiao Chang Fa , Jia Shi Ru
Published: September 2009

By phase inversion process, the polyvinylidene fluoride (PVDF) with polyvinyl chloride (PVC) blend membrane was prepared. In which, as pore-forming agents, the polyethylene glycol (PEG), poly(vinylpyrrolidone) (PVP) and lithium chloride (LiCl) was separately added into PVDF/PVC casting solution. The effect of each pore-forming agent on the kinetics of membrane formation and properties of PVDF/PVC blend membrane were investigated respectively. Using the capillary flow porometry, the microstructure and morphology of PVDF/PVC blend membrane were quantitatively characterized.
The results show that by respectively adding PEG, PVP or LiCl, it emphasizes the rate of solvent diffusion from PVDF/PVC solution during the phase inversion or membrane formation, and the porosity of membrane gets increasing. The pure water flux of PVDF/PVC blend membrane achieves enhancement obviously. At the same time, the rejection is decreased in a certain degree. Comparison with PEG or LiCl, PVP has more effect on the membrane pore-forming action. The microstructure analysis indicates that based on the same formulation, by selecting PEG or LiCl as pore-forming agent, formatted PVDF/PVC blend membranes achieve equivalent mean pore size. However, there is a little larger mean pore size distributed in the membrane by using PVP instead of PEG or LiCl. The application of purifying ε-polylysine (ε-PL) by using the PVDF/PVC blend membrane with PVP, the results reveal that the protein removal rate can be around 62.33% and the filterable and permeated ε-PL kept at 70.79% yield.
A Novel Bioadhesive Protein of Silk Filaments Spun Underwater by Caddisfly Larvae
Authors: Wang Yu Jun , Sanai Kazumi , Nakagaki Masao
Published: September 2009

Aquatic Larvae of Stenopsychid caddisfly (Stenopsychie marmorata) survive by attaching its catching nets at the bottom of the rocks in the flowing water. It was hypothesized that S. marmorata larva connects small pebbles by producing both silk-like protein and strong adhesive protein simultaneously. A 98 kDa protein（Smap-98k）was identified as an adhesive component by constructing a silk gland –specific cDNA library of S. marmorata. The cDNA sequence of Smap-98k was 2,679 bp long and encoding a 893 amino acids–long open reading frame (ORF) in which the first 19 residues are predict to be the signal peptide. The alignment of the Cys residues indicated the primary structure of this protein to consist of 15 degenerated repeats, each about 50 residues long and contains 6 conserved Cys residues. The Smap-98k was characterized by an abundance of Cys residues and charged amino acids with epidermal growth factor-like (EGF-like) structure. The most common amino acid of this protein was Cys (11.98%), with Pro (9.91%) and Glu (9.26%) following order of magnitude. Cys was assumed to play a role in maintaining the topology of charged amino acids on the molecular surface by intramolecular disulphide-bond formation. The gene was expressed specially in the silk gland similarity to the major silk proteins such like heavy fibroin (H-fibroin) and Light fibroin (L-fibroin) of S. marmorata larvae. The sequence of the protein showed certain homology to the silk-185 kDa of Chironomus pallidivittatus (Midge) which also spin silk underwater. The characterizations of abundance of Cys residues and charged amino acids also shared by Megabalanus rosa cement protein (Mrcp-20k ) and Mytilus galloprovincialis foot protein 2 (Mgfp 2) which both were produced in the marine environment. Although the similarity among Smap-98k, Mrcp-20k and Mgfp 2 sequences were very low, the functional relationship in underwater adhesion of these proteins should be noted.
Electrodeposition of Silicon in Organic Solvent Containing Silicon Chloride
Authors: Ma Qiu Ping , Liu Wen , Wang Bao Cheng , Meng Qing Sen
Published: September 2009

In this paper it was investigated that silicon be electrodeposited in the room temperature from propylene carbonate solvent. Cyclic voltammograms indicated that it was possible to electrochemical reduction of silicon chloride at -2.3984V versuHg/Hg2Cl2/ KCl (saturation) quasi-reference electrode. Potentiostatic electrolysis yielded deposits, accompanied by the change in electrolyte color from transparent to brown. Scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) were used to characterize the physical properties of the silicon. The EDS analysis performed simultaneously with SEM observation demonstrates that the deposit consists of Si, O and Cl.
Preparation and Structural Phase Transitions of Silver Palmitate
Authors: Li Ya Ling , Wang Shui , Zhang Xu , Yang Xiao Ling
Published: September 2009

Silver palmitate was prepared by chemical deposition method using palmitate acid, sodium hydroxide and silver nitrate as raw materials in water system. The structure and thermal properties of silver palmitate were characterized by SEM, XRD, FTIR, TG and DSC. The results show that silver palmitate has a good purity and well-defined layer structure with triclinic phase. TG and DSC curves demonstrate that silver palmitate decomposed at 230 and 250oC. One of the decomposed products at 230oC is a free acid with melting point at 52oC. The endothermic peak at 120oC attributes to the order-disorder phase transition. The three endothermic peaks at 159, 166 and 175oC assign to reversible phase transitions among intermediate phases.
Permanent Mold Suction Casting for TiAl Based Alloys
Authors: Su Yan Qing , Ye Xi Cong , Guo Jing Jie , Luo Liang Shun , Wang L. , Fu H.Z.
Published: September 2009

A novel precision casting technique for TiAl based alloy was described in this work, called the permanent mold suction casting technology，and the blades of Ti-47Al-2Si、Ti-47Al-2W-0.5Si、Ti-47Al-2W-0.5Si -0.5B were get by this technology. The structures of these blades were studied. The results of this study indicate that microstructure is sensitive to heat treatment and composition. The average grain size is 30 um before heat treatment. The grain size of TiAl based alloy is grossed by heat treatment at 1573 for 5h and furnace cooling, especially Ti-47Al-2Si. The addition of boron, the grain size of Ti-47Al-2W-0.5Si-0.5B is smaller than Ti-47Al-2W-0.5Si. The γ-TiAl based alloys have equiaxed grain in cross section, but the surface microstructure of γ-TiAl based alloys have more fine equiaxed grain than inside due to high cooling rate of mold.
Effect of Rolling Technology on the Microstructure and Properties of High Active Aluminum Alloy Anode
Authors: Liang Shu Quan , Zhang Yong , Mao Zhi Wei , Tang Yan , Guan Di Kai
Published: September 2009

The effect of rolling technology on the microstructure, electrochemical property and anti-corrosion property of Al-Mg-Sn-Bi-Ga-In alloy anode in alkaline solution (80°C, Na2SnO3 + 5mol/L NaOH) has been analyzed according to the chronopotentiometry (E-T curves), hydrogen collection tests and modern microstructure analysis. The results show that when controlling the pass deformation at 40%, with the increase of rolling temperature, both electrochemical activity and anti-corrosion property of Al anode increase first and then decrease. When the rolling temperature is 420°C, the aluminum alloy anode has the most negative electrode potential of about -1.521V (vs.Hg/HgO) and the lowest hydrogen evolution rate of 0.1716mL/ (min•cm2). The optimum comprehensive performance of Al alloy anode has been obtained.
In Situ Growth of Carbon Nanotubes in Hydroxyapatite Matrix by Chemical Vapor Deposition
Authors: Lu Xiao Ying , Wang Hao , Xia Sheng Yi , Wang Jian Xin , Weng Jie
Published: September 2009

Carbon nanotubes (CNTs)/hydroxyapatite (HA) nanocomposites have been successfully fabricated by a novel method for the biomedical applications, which is in situ growing CNTs in HA matrix in a chemical vapor deposition (CVD) system. The results show that it is feasible to in situ grow CNTs in HA matrix by CVD for the fabrication of CNTs/HA nanocomposites. Multi-walled CNTs with 50-80 nm in diameter have been grown in situ from HA matrix with the pretreatment of sintering at 1473K in air. The nanocomposites are composed with carbon crystals in CNTs form, HA crystallites and calcium phosphate crystallites, one of most important CaP bioceramics. And the CNTs content is about 1% proportion by weight among the composites in our experiments, which can enhance the HA mechanical properties and the CNTs content does not affect the HA performances. These CNTs/HA nanocomposites have the potential application in the biomedical fields.
Research on the 1.06 μm Reflectivity of Subwavelength Surface-Relief Structure via Finite Different Time Domain Method
Authors: Huang Wen Juan , Lu Chun Hua , Tan Wei Min , Zhang Yan , Xu Zhong Zi
Published: September 2009

In this paper, setting 1.06 μm Gaussian modulated pulse electromagnetic wave as irradiation sources, the influences of structural parameters on reflectivity are analyzed by finite different time domain (FDTD) method. The results show that the filled factor and height are key factors for circular tube relief structure with non absorption. The optimal height could be set to 0.2 μm, which is one odd time of the ratio of incident wavelength λ and four equivalent refractive index 4N, then the best filled factor is between 0.7 and 0.9, the ratio of inner and outer diameter could be set between 0.4 and 0.6, and the structure period has little significant influence. Compared with cylinder solid structure, it has been discovered that circular tube hollow structure could weaken the backward energy of electromagnetic wave, and it would be more suitable for antireflection structure than solid cylinder structure. Moreover, we design two another circular tube relief structures simulations with different extinction coefficients, it is found that the reflectivities are lower up to 0.00016% than the non absorption one.
Phosphotungstic Acid/Semi-Coke Catalysts for Oxidative Desulfurization of Diesel Fuel
Authors: Wang Liang , Li Chun Hu , Hou Ying Fei
Published: September 2009

This work presents the results obtained in the development of phosphotungstic acid/semi-coke catalysts in the oxidative desulfurization (ODS) process of diesel oil using hydrogen peroxide as the oxidizing agent. Phosphotungstic acid /semi-coke (60wt%) prepared by impregnation. These catalysts were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), The effect of the amount of catalyst used , on the efficiency of desulfurization was investigated. In addtion. the diesel after oxidation and extraction was analyzed by GC-FPD for sulfur content. The chromatograph shows that virtually all the sulfur containing compounds in diesel were removed.
Fabrication and Evaluation of Electrolyte-Supported Hollow Fiber Solid Oxide Fuel Cells
Authors: Yang Chun Li , Li Wei , Zhang Shang Quan , Liu Jian Jun , Chen Chu Sheng , Liu Wei
Published: September 2009

YSZ electrolyte-supported hollow-fiber SOFCs were successfully fabricated and their electrical and mechanical properties were investigated. The as-prepared hollow fiber SOFCs show a high mechanical strength of 149.0 MPa and 177.9 MPa before and after reduction by hydrogen gas, respectively. The open circuit voltage (OCV) values are greater than 1.0 V and the maximum power densities reach 146 mW cm-2 at 800°C, using wet H2 (～3% H2O) and static air as fuel and oxidant gas, respectively. As a result of high packing densities, this kind of YSZ electrolyte-supported hollow-fiber SOFCs has a high potential for practical applications.
Hydrogen Permeation Performance and Chemical Stability of Ni-La1.95Ca0.05Ce2O7-δ in an H2S-Containing Atmosphere
Authors: Yao Li Tao , Fang Shu Min , Liu Wei
Published: September 2009

In this paper, the hydrogen permeation performance of Ni-La1.95Ca0.05Ce2O7-δ (Ni-LDC) was measured in an H2S-containing atmosphere at 1073K. In 75, 150 and 300 ppm H2S, the hydrogen permeation flux decreased by about 5%, 15%, 30% respectively. XRD analysis revealed that sample showed a little formation of Ni3S2, La2O3, LDC, Ni, Ce2O2S. Based on the analysis of the microstructure and phase composition, and results of thermodynamic calculation, we suggested that the reaction between H2S and CeO2 is main cause of hydrogen permeation performance of the Ni-La1.95Ca0.05Ce2O7-δ cermet lossing.
Research on Purification of Attapulgite Clay and Adsorption Characteristics for Metal Cations
Authors: Zhang Zhi Hong , Zhang Shao Yu , Liu Xue Dong
Published: September 2009

Attapulgite clay(ATP) from Xuyi county of China was purified by a wet method then treated with NaOH and 1.0 mol/L, 2.0 mol/L and 3.0 mol/L solutions of HCl. Transmission electron microscope(TEM) and X-ray diffraction (XRD) were used to characterize treated ATP. Results showed that wet purification could remove most of impurities. Treatment by alkaline and HCl of 1.0 mol/L and 2.0 mol/L could increase purity while treatment of 3.0 mol/L hydrochloric acid could dissolve some element of ATP so much as form SiO2 and destroy fiber structure to clips. Adsorption experiments of Fe3+ and Ni2+ from aqueous solutions were done using original ATP, purified ATP and treated ATP as absorbents. Results showed that Attapulgite could adsorb metal cations in significant amounts. Sodium hydroxide activation had little influence on adsorption capacity. Influences of acid treatments to ATP on adsorption capacity varied on different concentration solutions.
Crystal Orientation and Surface Morphology of Sono-Electroplated Zinc Film from Alkali Zincate Bath
Authors: Chiba Atsushi
Published: September 2009

Zn plated on Cu plate from 0.65 mol/dm3 alkali zincate solution in 8 mol/dm3 KOH bath Electrolysis was carried out as current density of 10 - 100 mA/cm2. The sonication was prepared 40 kHz. The current efficiency was 76.1 % at 10 mA/cm2 in 0.10 mol/dm3 zincate and 100 % in 0.15 mol/dm3 zincate at 50 mA/cm2. The current efficiency and thickness of diffusion layer affected with the agitation of micro-jet. Surface of film was smooth and dense as particle crushed down with the shockwave pressure. (112) plane moved horizontally to <113> direction under the compressive stress or shearing stress.
Manufacturing of Heavy Plates with Excellent Mechanical Properties by a 40t ESR Furnace for Slab Products
Authors: Geng Xing , Jiang Zhou Hua , Liu Fu Bin , Peng Hao
Published: September 2009

A special bifilar 40t electroslag remelting(ESR) furnace for slab products has been fabricated to produce heavy plates for special application. The slab ingots were rolled to heavy plates, and then the mechanical properties of which were investigated. The impact toughness of heavy plates with different position, directions and under welding condition were performed at the temperature ranging from -70°C to room temperature. The tensile experiments at room temperature were carried out to check the tensile properties of heavy plates in different position, directions and under welding condition. The secondary cooling technology developed improves greatly the quality of solidification. Adjusting taper of the mold and using CaF2-CaO-Al2O3-SiO2-MgO slag are necessary for improving surface quality of the ESR slab. The ESR slabs with the maximum thickness of the world in size of 980 mm thickness, 2000 mm wideness and 2800 mm length have been produced successfully. The heavy plates with 410 mm in thickness can be obtained after rolling the 40 tons ESR slabs. The results of mechanical properties show that the heavy plates produced by ESR furnace for slab products exhibits excellent ductility, impact and isotropic properties in different position, directions and under welding condition.
Effect of Steel Slag Powder on the Durability of High Performance Concrete
Authors: Li Yun Feng , Liu Yang , Du Rong Qiang , Kong Fan Ying
Published: September 2009

dvanced mineral admixtures can lead to economical high performance concrete with enhanced durability and reduced cement content. When super fine steel slag powder is mixed into concrete as active admixture, resistance to abrasion and resistance to chloride penetration are improved as well as workability and mechanical properties of the concrete. Resistance to abrasion of steel slag concrete is measured and resistance to chloride penetration is also determined by the method of NEL and ASTM C1202 in this paper. Result shows that compound mineral admixtures as partial replacement for Portland cement in mortar enhance abrasion resistance. Mixing mineral admixture is an effective means for controlling the chloride permeability. Concrete specimens prepared with compound mineral admixture with steel slag powder and blast furnace slag powder has very low permeability.
Study on the Toughness Performance of Polypropylene Fiber and SBR Polymer Latex Modified Cement Mortar
Authors: Xu Fang , Zhou Ming Kai , Shen Wei Guo , Li Bei Xing
Published: September 2009

In this paper, polypropylene fiber and SBR polymer latex are added into cement mortar to improve the toughness. Using two flexural toughness test methods of ASTM-C1018 and JSCE-SF4, the ratio of compressive strength to flexural strength (σC/σF for short) and flexural toughness index are used to evaluate the toughness of the cement mortar. The experimental results show that, comparing to the control cement mortar sample, when the SBR polymer mass percent of 20% and the polypropylene fiber volume percent of 1.0%, the σC/σF is 2.17, reduced by 59.2%, the ASTM toughness index I5, I10, I30 is 2.86, 2.95, 3.16 respectively, increased by 63.4%, 58.6%, 68.1% respectively, the JCI toughness index is 13.1, increased by 258%. Based on the SEM, adding SBR-polymer into cement mortar can form the polymer transition layer between the interfaces of polypropylene fibers and cement matrix, from XRD test, SBR polymer latex has no significant influence on the cement hydration after 7d curing. This research provides some useful references for the application of this new material.
Investigation on Interlaminar Mechanical Properties of Hybrid CFRP/VGCF Laminates
Authors: Li Yuan , Hori Naoki , Arai Masahiro , Fukunaga Hisao , Hu Ning
Published: September 2009

In order to improve the interlaminar mechanical properties of CFRP laminate, hybrid CFRP/VGCF laminates have been fabricated by newly-developed powder method. The critical load at crack growth Pc and fracture toughness GIC have been found to be increased with VGCF interlayer through double cantilever beam (DCB) tests. Fracture surfaces of DCB specimens have also been observed to interpret this improvement mechanism. Moreover, numerical simulations using finite element method (FEM) with cohesive elements have been carried out to analyze the delamination propagation. The numerically obtained interlaminar tensile strength of hybrid CFRP/VGCF laminates has also been verified to be higher than that of base CFRP laminates.
Microstructure and High Temperature Oxidation of the Hot-Dipping Al-Si Coating on Low Carbon Steel in Ethanol, Water Vapor and Air at 700°C
Authors: Badaruddin Mohammad , Wang Chaur Jeng
Published: September 2009

Low carbon steel was coated by hot-dipping into a molten Al-10%Si bath. The high-temperature oxidation was performed at 700oC for 1 h to 49 h in air, air +100% H2O, and air + 30% ethanol under atmospheric pressure. An elemental composition distribution, morphologies of the aluminide layer and the oxide scale were characterized by OM, XRD, and SEM/EDS. After hot-dipping treatment, the coating layers consisted of Al, Si, FeAl3, τ5-Fe2Al8Si, and Fe2Al5. The results of high temperature oxidation tests showed the oxidation rate were parabolic law in three different atmospheres. The polyhedral τ1-(Al,Si)5Fe3 formed at a short time oxidation completely transformed to FeAl2 and FeAl due to the composition gradient and the chemical diffusion. The effect of water vapor on the oxidation resistance of the Al-Si coating may be attributed to increase in Al and Fe ions transport, leading to loss of protective aluminide layer by formation of iron oxide nodules on the coating surface and at interface between aluminide layer and the steel substrate.
Experimental Study for Performance Influence of Various pH Values on Pavement Straw Composite Fibers
Authors: Xue Qiang , Wang Jing , Feng Xia Ting , Liu Xiao Li
Published: September 2009

Pavement straw composite fibers (PSCF), a new material, were independently invented and developed by blending agriculture waste straw and modified bentonite, as showed in this paper. The chemical corrosion properties of PSCF in different pH values were test in microscale, and digital imaging processing technology was adopted to analyzing quantitatively the physical and mechanical properties, including particle area, pores connectivity rate and compressive strength, before and after PSCF were corroded. Research results show that the particle area of acidified PSCF is smaller than that of alkalized PSCF, however, the fractal dimension of acidified PSCF is bigger than that of alkalized PSCF. The change of PSCF microstructure has significant effect on its macromechanics properties. The compressibility of acidified PSCF was obviously bigger than that of alkalized PSCF, so the strength of acidified PSCF decreased significantly with the acidifying time increasing. The main reason was gradually decreasing of the particle area, decreasing of the fractal dimension and the loose tendency of fibers particle distribution. The interaction between mineral composition of PSCF and hydrochemistry solution was the basic factors determining straw structural characteristics, and the physical and mechanical properties of PSCF were affected by its structural characteristics. The main process was that mineral compositions of PSCF were cemented by the corrosive action of hydrochemistry solution, or some compositions were dissolved and precipitated, the porosity and particle area of PSCF, the arrangement pattern of soil particles as well as other microstructures changed. And deformation properties of PSCF changed correspondingly with the change of PSCF structure shape. Moreover, the constitutive model of PSCF with effect of acid and alkali was presented according to test data of digital image. It provided reliable techniques to quantitatively evaluate the pavement performance of PSCF in micro and macro scales. Furthermore, the chemical corrosion theory was improved, and the reference for constitutive model research was provided.
Hydrothermal Synthesis and Electrochemical Study of VOx/CNTs Composites
Authors: Zhu Quan Yao , Hu Si Ping , Wu Fei , Chen Wen
Published: September 2009

Vanadium oxide/carbon nanotubes (VOx/CNTs) composites were prepared by sol-gel hydrothermal synthesis. The composites were characterized in terms of surface morphology and structure using SEM, TEM, XRD, FT-IR, respectively. The electrochemical behaviors of the composites were investigated by means of galvanostatic charge-discharge cycling. The result shows that the vanadium oxides nanotubes and carbon nanotubes contacted each other and the composites have great cycleability as well as capacity characteristics which arrived at 303.5 mAh/g in the first discharge process and 200.4 mAh/g after 50th discharge cycles.
Preparation of Semi-Solid Billet with Less Liquid Content of 7A09 Aluminum Alloy by Partial-Melting Method
Authors: Wang Wei Wei , Song Jian Li , Yu Jing Bo
Published: September 2009

Preparation of semi-solid microstructure with less liquid content of 7A09 aluminum alloy industrial extrusion billets is studied in this paper. In the treatment, melting-stirring and predeformation of the alloy billets are not required. The influences of different heating temperatures and insulation time on the microstructure evolution are studied and the obtained microstructure is observed and analyzed by optical microscopy. The results indicate that a fine microstructure can be obtained with the proposed process and the processing parameters can be controlled over a wide range. The liquid content can be controlled within a certain range.
Study on Antibacterial Mechanism of Ag-Inorganic Antibacterial Material Containing Lanthanum
Authors: Tang Xiao Ning , Zhang Bin , Xie Gang , Xia Xue Shan
Published: September 2009

Inorganic antibacterial materials consist of the antibacterial ions, the additives and the carrier. In this study, we synthesized a new inorganic antibacterial material, of which Ag+ was selected to be the antibacterial ion, lanthanum nitrate served as the additives, and the white carbon black was chosen as the carrier, which was prepared by a sol-gel method. The as-synthesized antibacterial material was characterized by inductively coupled plasma, particle size measurement instrument, and enumeration tests. The result showed that this material has loose and dispersive structure, good thermal and light stability. The possible antibacterial mechanism was also proposed through all the experimental data in this study.
Interface Strength and Structure of Explosive Welding Sainless Steel-Aluminum Clad
Authors: Liu Hong Wei , Yu Jing Bo
Published: September 2009

The interface is the area where two type of materials are connected, the strength and property of interface are important for the application of the clad. In this paper, interfacial strength and fracture properties of stainless steel-aluminum clad are analyzed with the methods of interfacial shear test and four point bending test, and the interfacial crack and the interfacial fracture structure are analyzed with SEM. The results show that the bonding of stainless steel and aluminum is successfully realized by explosive welding, the interfacial shear strength reach 70.90MPa, and the interfacial energy release rate is 1.725 MPa•m, the thickness of transition layer is about 10μm at the interface, the interfacial fracture happen and extend in the transition layer along the interface and the interface fracture structure is inclined to brittle fracture.