bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro Assessment of Antibacterial Activity and Cytotoxicity of Silver Contained Antibacterial HA Coating Material
Authors: Zhu Zi Yuan , Zhang Fu Qiang , Xie You Tao , Chen Yi Kai , Zheng Xue Bin
Published: August 2009

Failure of dental implant is often caused by specific pathogenic bacteria. In this paper, antibacterial HA coating was prepared by vacuum plasma spraying with silver loaded zirconium phosphate containing HA as feedstock. The antibacterial activity against Aa，Fn and Pg was evaluated using a film covering method. MTT colorimetric assay was used to measure cytotoxic effect of the antibacterial HA coatings. Results show that the HA coatings displayed significant antibacterial activity against Aa，Fn, Pg and no cytotoxicity to L929 murine cell lines when the content of silver-loaded zirconium phosphate antimicrobial is between 5wt% to 10wt%. The sensitivity of the bacteria to the antibacterial HA coating is in sequence of Pg >Fn >Aa.
The Effect of Filler on the Properties of Silicone Rubber
Authors: Liu Jie Sheng , Wu Shao Peng , Chen Mei Zhu , Mi Yi Xuan
Published: August 2009

Fillers play important roles in the performances of silicone rubber, such as mechanical and physical properties. In this paper, the silicone rubber filled with silica in a wide volume range was measured in order to study the effects of filler loading on the mechanical properties of silicone rubber. The composites samples added with surface treated silica filler was characterized by Scanning Electron Microscopy (SEM) and fluorescent microscope with that reinforced by the unmodified filler as a comparison. The results showed that the surface treated filler are more easily diffused without agglomerate in the polymer network compared to the unmodifiedd filler. Incorporation of modified filler loading leads to the increase in both tensile strength and the elongation at break, but along with further increase in filler content, mechanical properties of silicone rubber decreased due to the filler particles aggregate state, which can be observed by SEM images. The tack-free time and the hardness of the silicone rubber decrease as the filler loading increases.
Improving Contact Damage Resistance of Thermal Barrier Coatings by Incorporating Buffer Layer
Authors: Jung Sung Il , Sim Young Seok , Kim Jae Hyun , Lee Je Hyun , Jung Yeon Gil , Paik Ung Yu
Published: August 2009

The effects of the introduction of a buffer layer between the bond and top coats on the indentation stress-strain behavior and the contact damage were investigated in air-plasma sprayed (APS) zirconia (ZrO2)–based thermal barrier coatings (TBCs). The microstructure is relatively continuous in the TBC system with the buffer layer, showing Zr, Ni, Cr, and Mg elements between the top and bond coats, whereas the Zr element suddenly disappears by passing the interface between the top and bond coats. The TBC system with the buffer layer shows less strain than that without the buffer layer in the higher stress regions above about 1.3 GPa, while both TBC systems become soft by forming the top coat in the lower stress regions compared with the substrate. The stress–strain curve in both TBC systems is dependent on the dwell time of thermal exposure condition. The TBC system with the buffer layer shows the lower stress-strain curves than that without the buffer layer in thermal cycles with the relatively short dwell time of 1 h, showing the reverse trend with the relatively long dwell time of 10 h. Subsurface damage in substrate is reduced at both indentation loads of P = 500 N and P = 2000 N by introducing the buffer layer, independent of thermal exposure. Therefore, the TBC system with the buffer layer is more efficient in protecting the substrate from contact environments than that without the buffer layer, showing cracking or delamination between the top coat and the buffer layer in the TBC system with the buffer layer.
Effect of SiC on Microstructures and Properties of Cordierite-Mullite Multiphase Ceramics Material
Authors: Bai Jian Guang , Wang Bo , Liu Guang Liang , Gao Ji Qiang , Yang Jian Feng , Zhao Jing Zhong , Li Zhen
Published: August 2009

In this paper, cordierite-mullite multiphase ceramics material was prepared using cordierite powder, mullite particles, fused silica, magnesia and alumina as main starting material. Effects of addition of 2%~10% SiC on the thermal expansion, flexural strength and thermal shock resistance were studied, and the fracture surface morphology was observed with Scanning Electron Microscope (SEM). The results showed that the multiphase ceramics material’s thermal expansion coefficient and flexural strength had little change. The thermal shock resistance of cordierite-mullite multiphase ceramics material varied as increasing-decreasing with the increase of SiC content, when the content of SiC was as high as 4%, the highest conservation rate of the flexural strength after 1100°C~water(3 times) was 72.08%, and the thermal shock resistance of cordierite-mullite multiphase ceramics material was superior.
Fracture Behavior of Plasma-Sprayed Thermal Barrier Coatings with Different Bond Coats upon Cyclic Thermal Exposure
Authors: Sim Young Seok , Jung Sung Il , Kwon Jae Young , Lee Je Hyun , Jung Yeon Gil , Paik Ung Yu
Published: August 2009

The effects of bond coat nature in thermal barrier coating (TBC) systems on the delamination or fracture behavior of the TBCs with different bond coats prepared using two different processes—air plasma spray (APS) and high velocity oxyfuel (HVOF)—were investigated by cyclic thermal fatigue tests. The TBCs with the HVOF bond coat were delaminated or fractured after 3–6 cycles, whereas those with the APS bond coat were delaminated after 10 cycles or show a sound condition. These results indicate that the TBC system with the APS bond coat has better thermal durability than the system with the HVOF bond coat under long-term cyclic thermal exposure. The hardness values of the TBCs (top coats) in both systems are dependent on applied loads, irrespective of the hardness of the bond coats and the substrate. The values are not responded to the bond coat nature or the exposure time. Thermally grown oxide (TGO) layers in both cases consist of two regions with the inner TGO layer containing only Al2O3 and the outer TGO layer of mixed-oxide zone containing Ni, Co, Cr, Al in Al2O3 matrix. The outer TGO layer has a more irregular shape than the inner TGO layer, and there are many pores within the outer layer. At failure, the TGO thickness of the TBC system with the HVOF bond coat is 9–13 m, depending on the total exposed time, and that of the TBC system with the APS bond coat is about 20 m. The both TBC systems show the diffusion layer on the side of substrate in the interface between the bond coat and the substrate. The relationship between the delamination or fracture behavior and the bond coat nature has been discussed, based on the elemental analysis and microstructural evaluation.
Dielectric Property of Laminated AlN/BN Ceramic Composites
Authors: Zhang Tao , Jin Hai Yun , Zhou Rui , Zhao Ji Feng , Jin Zhi Hao
Published: August 2009

The relationship between the processing technology and the dielectric property of the laminated AlN/h-BN ceramic composites has been studied. The results showed that the main polarization mechanism of laminated ceramic composites in low frequency range is space charge polarization at the interface of AlN layer and BN layer. Due to the affection of porosity, the permittivity increases and the dielectric loss decreases with increasing the hot pressing temperature. The permittivity increases and the dielectric loss decreases with increasing thickness ratio of different layer., Both permittivity and dielectric loss increase with increasing the content of AlN doping in BN layer.
Fabrication and Hardening Treatment for SiC/AlN Ceramic Composites
Authors: Jin Hai Yun , Li Ying , Jia Xiang Ya , Qiao Guan Jun
Published: August 2009

In order to obtain machinable ceramic with high hardness and strong mechanical properties, the SiC/Al/h-BN Composite Ceramics were fabricated by a new method which prepared the machinable pre-sintered body by Plasma Activated Sintering (PAS) and increased it's mechanical properties after hardening treatment. The results showed that the machinability and density of the pre-sintered h-BN/Al/SiC ceramic composites were excellent, and after hardening treatment, the mechanical properties (hardness, bending strength and density) increased obviously.
Effect of Aluminum Addition on Synthesis of Ti3SiC2 by Vacuum Sintering
Authors: Yang Jun , Xu Shao Chun , Cui Ya Ru
Published: August 2009

High purity Ti3SiC2 ceramic was synthesized by mechanical alloying and vacuum sintering. The effect of aluminum (Al) content on the properties and processing of Ti3SiC2 was investigated. The results showed that proper addition of a definite amount of Al could obviously increase the purity of Ti3SiC2, and was favorable for reducing the sintering temperature of Ti3SiC2.
Electrochemical Properties of LiFePO4/C Composite Improved by High Energy Milling
Authors: Kim Chang Sam , Hwang Sung Ik , Kim Shin Woo
Published: August 2009

The electrochemical properties of LiFePO4 as a cathode of lithium ion batteries considerably depend on a particle size of LiFePO4 and a condition of carbon coating. In this study, LiFePO4 powders were prepared using ultrasonic spray pyrolysis method, and then LiFePO4/C composites were made by infiltrating sucrose solution into LiFePO4 powders, drying, high-energy milling and annealing. The effects of high-energy milling were analyzed by comparing with electrochemical properties of powders synthesized without high-energy milling. It was found that the milling process drastically reduced the particle size of synthesized powders and electrical conductivity, and improved discharge capacity, cycle stability and rate performance.
Low Temperature Transformation of 3 mol% Yttria Stabilized Zirconia Coatings Deposited by Air Plasma Spraying
Authors: Liang Bo , Chen Huang , Ding Chuan Xian
Published: August 2009

The low temperature transformation of ZrO2-3 mol% Y2O3 coatings were investigated at 40 ~100oC using Raman spectroscopy. The results show that the low temperature transformation of ZrO2-3 mol% Y2O3 coatings is considerably effected by water temperature and mainly occurred on the coating surface. However, the transformation can be retarded by addition of Al2O3. The reasons lie in that the addition of Al2O3 can result in improvement of deposition efficiency and Young’s modulus of ZrO2-3 mol% Y2O3 coatings containing Al2O3.
Analysis of Anti-Seismic Performance of HRB500 Steel in Fire
Authors: Ma Hong Bo , Li Jin , Yang Jun
Published: August 2009

HRB500 has been recognized an excellent material for structure. In this paper, Fire Dynamics Simulator (FDS) computer emulator method was adopted to analyze the bending performance and reinforcing ratio of HRB500 and conventional steel bar at the surface temperatures 600°C-900°C and center temperatures of 100°C-300°C underwent fire. The results showed that the HRB500 reinforced bar possessed superior seismic performance after the fire and this is helpful to the future application and design of steel for engineering.
Microstructure and Flexural Property of CaCO3 Whisker Reinforced Epoxy Composite Material
Authors: Liu Peng , Shi Hui Cheng , Jin Hai Yun , Gao Nai Kui , Peng Zong Ren
Published: August 2009

Reinforcement was performed to epoxy resin by CaCO3 whisker, and the effect of flexural property of CaCO3 whisker reinforced composite materials was studied. The microstructures of the composite materials were observed by SEM. The results showed that the flexural strength of the composites increased with increasing CaCO3 whisker content, and the flexural strength reached to the maximum value when CaCO3 whisker content was about 15wt.%, and the maximum value was about 11% higher than that of pure epoxy resin. But, the strength would drop sharply with the excessive CaCO3 whisker.
Hybrid Tooling Using High Speed Cutting and Other RP (Rapid Prototyping) Technologies
Authors: Kwon Hong Kyu , Kim Kwang Soo
Published: August 2009

“Getting to market first” is extremely intensive pressure on the companies in this competitive business environment. The speed at which products are developed and released to market is tightly linked to profitability and market share. Hence, many companies are still in a desperate need of real Rapid Tooling (RT) technologies which can really help expedite their prototype tooling and pre -production tooling for injection molding. This paper describes how HT (Hybrid Tooling) process has been being successfully established and effectively applied with Metal filled SLS technologies.
Fabrication and Characterization of Barium Aluminum Silicate-Silicon Nitride Composites
Authors: Wang Bo , Guo Rui , Gao Ji Qiang , Yang Jian Feng
Published: August 2009

The barium aluminum silicate-silicon nitride (BAS-Si3N4) matrix-ceramic composite was fabricated using pressureless sintering, at temperatures ranging from 1720°C, which is below the melting point of BAS, to 1850°C. The effect of processing conditions on sinterability, crystalline structure, microstructure and mechanical properties was evaluated. It was demonstrated the BAS glass-ceramic served as an effective liquid-phase-sintering aid, to attain high densities and completed the α-Si3N4–β-Si3N4 phase transformation, and remained as a structural matrix that was reinforced by the rod-like β-Si3N4 grains. Si3N4 grains nucleated and grow in random directions in an almost completely crystallized matrix of hexacelsian BAS. High flexural strength (665±40 MPa) and fracture toughness (7.74 MPa•m1/2) could be obtained from 30wt%BAS-70wt%Si3N4 samples that have been sintered at 1800°C for 120 min with a fine-grained microstructure.
The Microstructural Deformation of the Montmorillonite Particles/Polypropylene/Polylactic Acid Nanocomposite Filaments Infused with Plasma Treated Montmorillonite
Authors: Zhu Hai Yan , Zhang Ying Chen , Zou Jing , Wu Hong Yan , Qiu Y.P.
Published: August 2009

The purpose of the present work is to investigate the microstructural deformation of the montmorillonite (MMT) particles/polypropylene (PP)/polylactic acid (PLA) nanocomposite filaments infused with plasma treated MMT. The activation volumes of the MMT/PP/PLA nanocomposite filaments ranging from 31.4572 to 151.2100 (nm)3 estimated by the Eyring’s equation quantitatively revealed that the plasma treated MMT acted as obstacles to dislocation motion during microstructural plastic deformation mechanisms. DSC analysis showed marked increases in glass transition temperature (Tg), indicating the plasma treated MMT could effectively help resist the free crankshaft movement of the macromolecular chain in the nanocomposite filaments. In addition, the MMT/PP/PLA nanocomposite filaments developed intercalated structures which had been examined by SEM.
Effects of Eu2+, Dy3+ Contents and Particle Sizes on the Luminescent Properties of SrAl2O4 Phosphor by the Sol-Gel Process
Authors: Shin Dae Yong , Kim Kyung Nam
Published: August 2009

A green emitting SrAl2O4:Eu2+, Dy3+ phosphor with high brightness and long afterglow was synthesized by the sol-gel method. SrAl2O4: Eu2+, Dy3+ phosphor exhibited broad band extending from 450 to 650 nm and maximum emission spectra peaking at 520 nm. Three excited levels existed, two shoulders were observed at 270 and 330 nm in addition to the maximum at 360 nm on the excitation spectrum. After the removal of excitation light, the excellent after-glow characteristic of the phosphorescence was obtained as a result of low decay time, although the after-glow intensities of phosphor varied exponentially with the time.
Investigation of Microstructure and Machinability of the B4C/BN Composites
Authors: Jiang Tao , Jin Zhi Hao , Yang Jian Feng , Qiao Guan Jun
Published: August 2009

In this article, the microstructure, mechanical properties and machinability of the B4C/BN microcomposites and the B4C/BN nanocomposites were investigated. Homogenous distribution of the h-BN particles in the B4C ceramics appeared. The mechanical properties decreased gradually with the increasing content of h-BN for the both composites, while the nanocomposites demonstrated high performance. Machinability increased gradually with the increasing content of h-BN, and excellent machinability exhibited for both composites with more than 20wt% h-BN. The weak interface between the B4C matrix grains and the h-BN particles as well as the cleavage behavior of the laminate structured h-BN particles significantly attributed to the machinability of the B4C/BN composites.
Study on Transition Characteristics of Poly(Ethylene Glycol)/ Selected Fatty Acids Phase Change Materials
Authors: Shi Qi Song , Liu Tai Qi
Published: August 2009

In the present study, poly(ethylene glycol)(PEG) with different molecular weights were blended with different fatty acids: capric, lauric or stearic acid as a thermal energy storage material. Latent heat thermal energy storages properties of the blends were evaluated by using the differential scanning calorimetry (DSC). The thermal analysis indicated that it is possible to obtain homogeneous PEG/fatty acid blends by mixing in the melt and subsequent solidification. The PEG-fatty acids blends had greater enthalpy and exhibited good thermal stability and can be used as a new kind of phase change material for thermal energy storage material for thermal energy storage and temperature control. The heat of transition for PEG10 000/ stearic acid (1:3 w/w) blend was on extremely high level of 253.2 J.g-1 which is 35% more than for pure PEG 10000
ZnO Nanorods Synthesized in Large-Scale via Sonochemical Method and its Sensing Potential towards Methyl Mercaptan
Authors: Zhang Shao Lin , Park Sun Min , Yu Jun Boo , Huh Jeung Soo
Published: August 2009

A novel and simple approach has been developed for a large-scale synthesis of ZnO nanorods using ultrasound radiation. Double-pod-like ZnO nanorods were directly grown from the starting precursors of zinc nitrate hydrate [Zn(NO3)26H2O] and hexamethylene tetramine (HMT) in deionized water without any templates or seeds. The obtained double-pod-like product had a diameter ranging from 80 to 150 nm and length ranging from 1 to 5 um. Scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) revealed that these products are of high purity, hexagonal and of single-crystalline structure. The ZnO nanorods synthesized were utilized for gas sensing application. Alumina plate consists of Pt interdigitated electrode was used as sensor substrate. The as-prepared products were transferred to the surface of substrate by screen printing method to fabricate the gas sensor. The sensing properties of the sensor were investigated toward methyl mercaptan (CH3SH). The sensor shows good and fast response towards methyl mercaptan at a fixed operating temperature. The high sensitivity may be ascribed to the high surface area and aspect ration of the double-pod-like nanomaterial.
Preparation and Properties of Nanoclay/TPS/Asphalt Ternary Binders
Authors: Wu Shao Peng , Wang Jin Gang , Zhang Yuan
Published: August 2009

After a preliminary investigation on the binary asphalt/clay binder, the ternary binder was prepared by adding the nanoclay and TAFPACK-SUPER (TPS) to the original asphalt. The previous research shows that exfoliated/intercalated layers homogeneously are dispersed in the asphalt matrix and the nanocomposite has formed. Rotation Thin Film Oven Test (RTFOT) and Pressure Age Vessel Test (PAV) results indicate that the modified asphalt with 3% organic nano-montmorillonite (OMMT) present better performance of aging resistance. The purpose of this research is to attain ternary asphalt binder with better rheological performance and aging resistance. The ternary modified asphalt binder containing 4% OMMT and 12% TPS by weight were prepared at the laboratory scale using high speed shearing mixer. The rheological properties of OMMT/TPS modified asphalt binders were evaluated before and after aging in present paper. Temperature sweep tests and frequency sweep tests were conducted to characterize the rheological properties of modified asphalt using Dynamic Shear Rheometer (DSR). According to the frequency sweep tests, complex modulus master curves were plotted to analysis the rheological properties. The results indicate that nanoclay/TPS/asphalt ternary binders have more excellent performance of rheological and aging resistance at both high and low temperatures, compared with the virginal bitumen and TPS modified asphalt.
Dispersing Single-Walled Carbon Nanotubes in Water by Adsorption of Polyphenols
Authors: Liao Qiu , Sun Jing , Gao Lian
Published: August 2009

Single-walled carbon nanotubes (SWCNTs) were dispersed in water with the assistance of polyphenols (resorcinol and pyrogallol). SWCNTs have intrinsic tendency to adsorb aromatic compounds due to π-π dispersion interactions, which leads to SWCNTs noncovalently dispersed in water by adsorption of resorcinol or pyrogallol. The concentration of SWCNT suspension was determined by the absorbance value at 500 nm using UV-Vis spectrometer. The effects of polyphenol concentration and ultrasonication time on the dispersion state have been investigated. Resorcinol of 0.5 mg/mL was found to be most effective for solubilizing SWCNTs in water. Over 60 % of SWCNTs were well dispersed with ultrasonication time for 4 hours. However, SWCNTs were cut shorter and damages could be introduced with prolonged ultrasonication time. TEM images showed that SWCNT bundles became thinner with the presence of polyphenols. These aromatic compounds provide an effective way to disperse SWCNTs in water and might have potential application in nanocomposite preparation.
Synthesis and Characterization of FePt Nanoparticle/Single Walled Carbon Nanotube Composites
Authors: Wang Yan , Gao Lian , Sun Jing , Liu Yang Qiao
Published: August 2009

We report the synthesis and characterization of FePt nanoparticles (NPs)/single walled carbon nanotube (SWNTs) nanocomposites, which might have important potential applications to orient CNTs and the development of new catalysts. The crystallite size of FePt NPs is about 2.5-4 nm and the Fe atom content ranges from 50% to 65%. HiPCO SWNTs have been decorated with FePt nanoparticles under mild conditions without any pretreatment. When the bundle size of HiPCO SWNTs is about 20 nm, FePt NPs mostly attach on the sidewalls of SWNTs. The loading of FePt nanoparticles on the SWNTs bundles can be conveniently controlled by adjusting the initial amount of FePt NPs. The nanocomposite showed magnetic properties in a magnetic field. TEM, HRTEM, and EDS spectra were performed to observe the nanostructure of these nanocomposites.
R-Curve Behavior of Machinable SiC/h-BN Nano-Composites
Authors: Jin Hai Yun , Zhou Rui , Qiao Guan Jun , Gao Nai Kui , Peng Zong Ren , Gao Ji Qiang
Published: August 2009

SiC/h-BN nano-composites powder was synthesized using an in-situ reaction method and SiC/h-BN nano-composites were fabricated by hot-pressing. Damage resistance and R-curve behavior of machinable SiC/h-BN nano-composites was evaluated using the indentation- strength-in-bending technique and compared with that of SiC/h-BN micro-composites and monolithic SiC. The results showed that SiC/h-BN nano-composites have better damage resistance and R-curve behavior than SiC/h-BN micro-composites and monolithic SiC.
Fabrication and Formation Mechanism of Flowerlike Bicephalous TiB2 Nanowhisker Clusters
Authors: Huang Fei , Fu Zheng Yi , Yan Ai Hua , Jia Tie Kun , Wang Wei Min , Wang Hao , Wang Yu Cheng , Zhang Jin Yong , Zhang Qing Jie
Published: August 2009

Flowerlike bicephalous titanium diboride (TiB2) nanowhisker clusters were fabricated by planetary ball-milling. The pure cleavage theory and crack growth mechanism were used to explain the formation process. The high-resolution transmission electron microscopy and nano electronic beam diffraction show that TiB2 superhard material always has a cleavage plane along the direction of [0001] zone axe and [10 0] zone axe because of its big interplane distance, weak bonding force between planes and low index directions. The flowerlike bicephalous TiB2 nanowhisker can be gained after repeated cleavage under high strains. The discovery could open a new path to fabricate C32 type superhard ceramic nanowhiskers.
Fabrication of La Doped ZnO Nanorods via a Solvothermal Route
Authors: Jia Tie Kun , Wang Wei Min , Fu Zheng Yi , Huang Fei , Wang Hao
Published: August 2009

La doped ZnO nanorods were synthesized via solvothermal technique using Zn(AC)2 and La(NO3)3 as starting materials. The products were characterized by X-ray diffraction (XRD), field scanning electron microscopy (FESEM) equipped with an energy dispersion X–ray (EDX) spectrometer, photoluminescence spectroscopy and UV-vis spectroscopy. The results of XRD in combination with EDS indicated that La was successful doped in ZnO. The obtained La doped ZnO sample exhibited nanorod like morphology and the diameter was about 30 nm. The photocatalytic property of La doped ZnO was evaluated by the variation of the concentration of RhB.
Preparation of Chitosan Grafting Acrylic Acid Supported Palladium Fibrous Catalyst and its Application in Hydrogenation
Authors: Yu Jian Xiang , Liu Tai Qi
Published: August 2009

Chitosan grafting acrylic copolymer (CTS-g-AA) supported Nano palladium catalyst was obtained in this paper. Chitosan grafting acrylic copolymer (CTS-g-AA) was prepared firstly and palladium was supported on CTS-g-AA; then nano fibrous catalyst was gained via electrospinning technique. The title catalysts were characterized by TEM, SEM and IR, the diameter of nanofiber was about 70~200 nm, the size of metal particles were in a range of 10~40 nm, and palladium particles dispersed on nanofibers homogeneously. The catalyst was applied to catalyze α-octene hydrogenation in normal temperature and pressure. The results showed that the conversion of α-octene was 99%, and the yield of octane was 65% by double-metal catalyst.
Synthesis and Luminescent Properties of Porous YVO4:Sm Nanoplates
Authors: Wang Ju An , Xu Yun Hua , Cen Qihong , Zhang Xiao Man , Cui Ya Ru
Published: August 2009

The present research describes a simple low-temperature synthesis route of fabricating porous YVO4:Sm nanoplates via a chemical co-precipitation method using commercially available Y2O3, NH4VO3, Sm2O3 and ethylene glycol as the reacting precursors. The as-synthesized YVO4:Sm was thermally treated at 300°C and 600°C for 2 h which is much lower than that of the conventional preparation methods. The obtained samples were characterized by FTIR, XRD, TEM and PL. The photoluminescence measurement revealed that the luminescence intensity was significantly increased with increasing annealing temperature.
In Vitro Cytocompatibility of Silver-Containing Hydroxyapatite Coatings
Authors: Chen Yi Kai , Zheng Xue Bin , Li Baoe , Xie You Tao , Ding Chuan Xian , Lee Soo Wohn
Published: August 2009

In this paper, antibacterial silver-containing hydroxyapatite coating was prepared by vacuum plasma spraying method and osteoblasts were seeded onto the surface of the coating to evaluate its cytocompatibility. The results indicated that the cells proliferated well on the samples, and the proliferation rate on the silver-containing hydroxyapatite coating was a little bit higher than that on the silver-free hydroxyapatite coating. The contact angle of water drop on the coating was measured, and it was found that the contact angles of the silver-containing hydroxyapatite coatings were smaller than the hydroxyapatite coating. The improvement of hydrophilicity for the silver-containing hydroxyapatite coating could be beneficial to the cells proliferation on its surface. It can be concluded that the addition of silver in the hydroxyapatite coating endowed the coating with antibacterial property while maintaining its excellent cytocompatibility.
Study of Machinable Dental Glass Ceramics
Authors: Ma Xin Pei , Li Guang Xin , Jin Zhi Hao , Chen Ji Hua , Yang Mao Ju , Han Yun Jie
Published: August 2009

Glass-ceramics are especially useful for the dental restorations because of their good biocompatibility, chemical stability, aesthetic, mechanical strength and wear resistance. The aim of this work was to obtain one mica glass-ceramic, which can be easily used for rapid machining into all-ceramic tooth with computer assisted design/computer assisted manufacture (CAD/CAM) devices. In the study, on the base of low melting machinable fluorosilicic mica glass ceramics, the effects of CeO2 and Fe2O3 in SiO2-B2O3-K2O-Na2O-Li2O-Al2O3-MgO-F system on color were studied. By orthogonal experimental design, the effects of crystallized parameters on the color, three point flexural strength and machinability of the glass ceramics were obtained, and the samples were analyzed by differential thermal analysis(DTA), X-ray diffraction (XRD) and scanning electron microscopy(SEM), respectively. Experimental results showed that the glass-ceramics with color close to the tooth can be obtained by adjusting the percentage of CeO2 and Fe2O3, and the glass-ceramics crystallized at 680°C for 2h have excellent mechanical properties and machinability.
Synthesis of Fluorine-Containing Organic Silane Reagent
Authors: Weng Rui , Zhang Lian Meng , Wang Chong Hui , Wang Shui Ping
Published: August 2009

Organic silane perfluorinated octyl sulfonic acid amide is synthesized by compounding aminosilane (N-(β-aminoethyl)-γ-aminopropyl trimethoxy silane) and perfluorinated octyl sulfonic acid fluoride. The results show that the product yield of 88% is achieved when the ratio of perfluorinated octyl sulfonic acid fluoride and aminosilane is maintained at 1:1.1 at 50°C for 2 hours.
Removal of Zn (II) from Aqueous Solution by Copolymer of Grafting Acrylic Acid onto Deacetylated Konjac Glucomannan
Authors: Liu Feng , Luo Xue Gang , Lin Xiao Yan
Published: August 2009

Removal of Zn (II) from aqueous solution by copolymer of grafting acrylic acid onto deacetylated konjac glucomannan (GADKGM) was evaluated in a bath adsorption system. Operational parameters such as pH, time, temperature and initial concentration were studied in present work. The adsorption process was relatively fast and highly effective. Removal efficiency for Zn(II) solution at the concentration of 100 mg/L was 98% at optimum operational pH of 6. The removal rate for Zn(II) on GADKGM was very fast and the removal efficiency can attain about 90% within 5 min. Isotherm adsorption data were described by Langmuir model with monolayer adsorption capacity of 125 mg/g. The negative values of thermodynamic parameters of △Go and △So indicated that adsorption process was a spontaneous process and randomness at the solid/liquid interface was decreased during the adsorption process.
Use of Recycled Calcium Slag for Clean Steel Refining
Authors: Zhan Dong Ping , Zhang Hui Shu , Gong Wei , Jiang Zhou Hua , He Ji Cheng
Published: August 2009

Calcium slag (CS) is a by-product generated during smelting to extract calcium metal from the ore by aluminothermic reduction method. The melting point, melting speed, viscosities, surface tensions and the refining effects of CS and normal premelted refining slag (NPRS) were measured in the laboratory. Then the plant trials were done in a 150 tons Ladle Furnace (LF) in a steelmaking plant during the refining of clean steel. The results show that the properties of CS are similar to those of NPRS, and CS is a good refining agent not only in laboratory experiment but also in industrial production. By using CS, the average final sulfur content in X70 pipeline steel reaches 25×10-6; the total oxygen content in GCr15 bearing steel is 5×10-6~8×10-6; the titanium content in GCr15 bearing steel is less than 20×10-6 and lower than the steels refined by using NPRS.
Compressive Strength of Brick Made from Waste Materials
Authors: Lee Woo Keun , Kim Tae Eun , Yoo Yeong Seok
Published: August 2009

The objective of this research was to make brick from waste materials, such as MSWI fly ash, water sludge and coffee sludge. It was made by mixing raw materials, drying at room temperature for 24 hrs, and at 60°C ~ 100°C for 1hrs. The dried bricks sintered to 1100 ~ 1150°C by 5°C/min and then kept at that temperature for 2hrs. Compressive strength, water absorption were measured to discuss the characteristics of brick prepared. Toxicity characteristic leaching procedure(TCLP) test is also used to evaluate the environmental safety.
The optimum condition was obtained at the mixing ratio as followed; 20:19.5:0.5:60 of MSWI fly ash, water sludge, coffee sludge and clay. Considering the value of compressive strength and water adsorption for prepared brick, it can be used as an alternative brick.
Influence of Different Interlayers Metals on Properties of Diffusion Bonding Joint of Tungsten to Copper
Authors: Li Jun , Fang Xu , Yang Jian Feng , Qiao Guan Jun
Published: August 2009

Ti foil and Ni foil interlayers were selected for the bonding of tungsten to CuCrZr alloy. The effects of bonding temperature on the microstructures and shear strength of the joints were performed. The interfacial bonding mechanism was studied through microanalysis. The results show that Ti foil was transformed into liquid solution and extruded mostly out of the bonding zone at 980°C, the strength of the joints can reach 136MPa due to the chemical and mechanical interfacial bonding. Ni foil was used for bonding of tungsten to copper alloy, the EDS analyses shows that the solid solution Ni(W) and the intermetallic compound NiW2 form in the diffusion layer at 920°C.
Influence by Difference of the Photocatalyst Nanoparticle Shape to Skin
Authors: Watanabe Eiji , Nishizawa Kaori , Miki Takeshi , Taoda Hiroshi
Published: August 2009

The influence of the titania photocatalyst nano-particles to the skin is to be doubted. We studied the influence of different titania photocatalyst nanoparticles shape to the artificial skin like the human body under the UV light irradiation conditions. The decomposition degree of the artificial skin was evaluated from the monitoring of the amount of carbon dioxide generated from them by the titania photocatalyst nanoparticle activity. When spreading their titania nanoparticles on the skin sample, the carbon dioxide generated from the skin was not detected in the apatite coating titania nano-particle sample through was detected the sample coating no apatite. The result was considered not to have existed the influence on the skin samples because the titania nano-particle was not to touch the skin sample directly.
Preparation and Photocatalytic Performance of Nano Titania-Coated Beads
Authors: Ha Jin Wook , Do Young Woong , Park Jae Hyun , Han Chul Hee
Published: August 2009

Fluidized Bed Chemical Vapor Deposition (FB-CVD) method offers advantages over conventional Chemical Vapor Deposition method in coating three dimensional objects. In addition, catalysts prepared by FB-CVD method often show improved physicochemical properties. Thus, FB-CVD seems a useful method for coating TiO2 onto small beads, in view of their photocatalytic application in aqueous environment, for example. In this work, we produced TiO2 coated beads (1~2mm in diameter) of alumina, silica-gel, and glass in ~35nm thickness using FB-CVD method, and examined photocatalytic performance of TiO2 coated beads in the photocatalytic decomposition reaction of methylene blue solution. Based on the combined results of the decomposition reaction kinetics of methylene blue and FE-SEM images of the surface morphology of TiO2 coated beads, we were able to account for the photocatalytic performance with respect to characteristic features detected in the surface morphology.
Improvement in Photocatalytic Activity of TiO2 by Addition of Small Amount of TiO2-xNy
Authors: Liu Bin , Wang Yu Hua , Yin Shu , Sato Tsugio
Published: August 2009

Nitrogen doped titania was coupled with the commercial titania nanoparticles by mechanical milling in liquid medium. When small amount of nitrogen doped titania was added into the commercial titania, higher intensity and longer lifetime of 1O2 was observed, and the photocatalytic activity was efficiently improved. The TiO2-xNy acts as the acceptor of photoinduced holes. The recombination of the electron-hole was effectively depressed by the heterogeneous electron transfer. This could be an effective way to obtain high active photocatalyst.
Effective of SiO2 Addition on the Self-Cleaning and Photocatalytic Properties of TiO2 Films by Sol-Gel Process
Authors: Shin Dae Yong , Kim Kyung Nam
Published: August 2009

Thin films of various composition in the system of TiO2•SiO2 have been fabricated by the sol-gel process using Si(OC2H5) and Ti(OC3H7i)4 as precursors. TiO2•SiO2 films were formed on the glass substrate by spin-coating technique and heated at 500°C for 1 h. The relationship between hydrophilicity, photocatalytic properties and self-cleaning property with SiO2 addition and UV light irradiation were investigated. Photocatalytic activity of TiO2•SiO2 films showed decomposition of ~97% of acetaldehyde in 2 h and a water contact angle of ~10°. TiO2•SiO2 films can have more hydrophilic activity and less photocatalytic activity by increasing of SiO2 addition. XPS measurements revealed that the amount of organic compounds adsorbed on the films decreased with the UV light irradiation and SiO2 addition, because of the increased of both OH group contents in films and decomposed organic contaminants of the films surface.
Buried-Layer Bared AZO/TiO2 Semiconductor Coupled Films and their Photocatalytic Properties
Authors: Zhang Xi Wen , Liu Cen Cen , Han Gao Rong
Published: August 2009

AZO/TiO2 double-layered semiconductor coupled films were prepared through sequentially depositing AZO and TiO2 films on glass substrates by radio frequency (RF) magnetron sputtering. PVP-pretreatment and post-annealing were performed on these double-layers to achieve an exposure of the AZO buried-layer in different baring conditions. The photocatalytic efficiencies of these buried-layer bared structures were measured through dye decomposition under ultraviolet irradiation. Silver mirror reactions were operated to explore a possible photocatalytic mechanism associated with these buried-layer bared conditions. The buried-layer bared AZO/TiO2 coupled films present 2 ~3 times of photocatalytic activity comparing to the normal AZO/TiO2 double-layered or single layered ones. It suggested that the self-built electrical field formed from coupling semiconductors reduces the recombination of electron-hole pairs, increases the yield of surface photogenerated charges, and enhances the photocatalysis.
Effects of Electrical Discharge Energy on Machining Performance of Sintered NdFeB Magnet
Authors: Li Li , Yuan Guang Ming , Niu Zong Wei , Hou Rong Guo
Published: August 2009

Sintered NdFeB permanent magnet is widely used in many areas because of its excellent magnet property. In this study, the machining parameters of electrical discharge machining (EDM) are varied to study the effects of electrical discharge energy on material removal rate and surface roughness of NdFeB magnet. Moreover, the micro-cracks on the machined surface induced by EDM are also examined. The experimental results reveal that the MRR increases with the electrical discharge energy. The number of surface cracks on the machined surface increases with the enhancement of discharge energy Thus, using EDM process to machine sintered NdFeB magnet depends on setting the machining parameters to prevent surface crack.
Viscoelastic Analysis on High Temperature’s Stability of Asphalt Pavement
Authors: Wang Hong , Wu Shao Peng , Pang Ling
Published: August 2009

Flexible pavement-asphalt mixture plays an important role in structures of the primary road and bridge at present. However, the mixture is a type of viscoelstic material and is sensitive to environment temperature, especially a high temperature. The permanent deformation due to high temperature and the material’s viscoelastic shorten the service life of the road and even lead to traffic accident. Therefore it is necessary to analyze the pavement’s mechanical performance. In the study, the viscoelastic constitutive equation of the mixture is transformed to Prony Series. The objective of this study is to characterize the stability of asphalt pavement at high temperatures with a three-dimensional finite element and accurately predict the pavement’s strain and stress in vehicle load.
The Electrodeposition of Nanostructured Ni-TiN Composite Films
Authors: Cai Chao , Yin Jun Ying , Zhang Zhao , Yang Jian Feng
Published: August 2009

The Ni-TiN nanocomposite films have been successfully fabricated onto commercial brass copper substrates using dc electroplating technique, and the microstructure and anti-corrosion properties of the optimized Ni-TiN nanocomposite have been respectively characterized using scanning electron microscopy (SEM). The results show that the morphology of Ni-TiN composite film is sensitively dependent on the electroplating current density, the concentration of TiN nanoparticles, the solution stirring speed, the bath temperature and the solution pH value.
Effects of Flow Characteristics in Polymer Electrolyte Membrane Fuel Cell
Authors: Kim Hong Gun , Kwac Lee Ku , Kim Yoo Shin , Kang Young Woo
Published: August 2009

An experimental and numerical study of polymer electrolyte membrane fuel cell (PEMFC) is presented and compared with the experimental data to investigate the effects of pressure gradient, flow rate, humidification and supplied oxidant type for the practical application. The membrane and electrolyte assembly (MEA) materials are implemented by double-tied catalyst layers. A single-phase two-dimensional steady-state model is is implemented for the numerical analysis. Testing condition is fixed at 60sccm and 70°C in anode and cathode, respectively. It is found that the performance of PEMFC depend highly on the conditions as gas pressure, temperature, thickness, supplied oxidant type (Oxygen/Air) as well as humidification. The results show that the humidification effect enhances the performance more than 20% and the pure oxygen gas as fuel improves current density more than 25% compared to ambient air suppliance as oxidant.
Mechanical Behaviour of High Density Polyethylene Based Foams
Authors: Lobos Juan , Rodríguez-Pérez Miguel A. , del Carpio Miguel , de Saja Jose A.
Published: August 2009

This paper presents the mechanical properties of a collection of high density Polyethylene based foams. The produced materials are characterised by a reduction in density up to 60%, an excellent surface quality, cell sizes in the microcellular range (around 50 microns) and a multi-structured cellular structure (cranial structure) with dense skin and foamed core. The mechanical properties of these materials showed linear relationships between Young’s modulus and density for densities above 0.7 g/cm3. In addition, variations in the cell size did not influence the elastic properties.
Estimation of Energy Requirements and Atmospheric Emission in Continuous Casting Process for Al Wire
Authors: Lee Byoung Soo , Cho Hoon , Jo Hyung Ho
Published: August 2009

Energy requirement and yield for production of aluminum wirerods manufactured by continuous casting process were investigated to enhance yield of aluminum wiredrods. Also, it was compared with conventional process including extrusion process. The enhancement of yield more than 30% could be accomplished through the continuous casting process. The conventional process including extrusion process for production of wirerods consumes more energy compared to continuous casting. In addition, a number of intermediate annealing may be introduced during wiredrawing process of wirerods manufactured by conventional process including extrusion process. It can be mentioned that continuous casting process is suitable process for wiredrawing process because it can save energy requirement not only during manufacturing process of wirerods but also during following wiredrawing process.
Analysis of the Grain Orientation and Texture of Friction Stir Welded Magnesium Alloy
Authors: Xu Wei Ping , Xing Li , Ke Ling Min
Published: August 2009

The grain orientations and microtextures in a friction–stir–welded magnesium alloy AZ80A were analyzed by Orientation Imaging Microscopy (OIM).The results showed that times random of grain orientations in the nugget zone were not strong and orientations were variety. They brought on very fine equiaxed grains. It also showed that deformation texture of {1,-1,0,4}<1,0,-1,0> was a few departure 20deg from the sample normal, The grains in the nugget zone from the base metal inherited the deformation texture of {1, -1,0,4}<1,0,-1,0> . It was concluded that re-crystallized grains in the nugget zone formed by a continuous dynamic re-crystallized mechanism.
Large Deformation of Metallic Hollow Spheres
Authors: Speich Marco , Rimkus Wolfgang , Merkel Markus , Öchsner Andreas
Published: August 2009

Hollow sphere structures are a new group of advanced lightweight materials for multifunctional applications. Within the scope of this paper, the uniaxial deformation behaviour in the regime of large deformations is investigated. Appropriate computational models are developed to account for the deformation mechanisms occurring under high deformations. Macroscopic stress-strain curves are derived and the influence of different material parameters is investigated.
Simulation of Aluminium Alloy 5A06 Warm/Hot Hydromechanical Sheet Deep Drawing
Authors: Lang Li Hui , Liu Bao Sheng , Liu He Jun , Lyamina Elena
Published: August 2009

The flow behavior and ductility of the Aluminium alloy 5A06 was investigated in the tensile test at the elevated temperatures from 20oC to 300oC and strain rates range of 0.0006s-1 0.06s-1. The influences of strain, strain rate and temperature to elongation strain at fracture , percentage elongation , tensile strength , strain hardening exponent and strain rate sensitive exponent were researched on the basis of experimental stress-strain curves, showing 5A06 is a temperature sensitive alloy. Warm/hot hydromechanical processing of cylindrical cup deep drawing was simulated. It is demonstrated that the differential temperature mode with cool punch and heated die can enhance the forming limit significantly compared with the constant temperature mode of all tools in the same temperature.
Deconsolidation of Polycrystalline Skeletons in Sintered Composite Materials
Authors: Lisovsky Anatoly F.
Published: August 2009

The present review covers the deconsolidation aspects of refractory polycrystalline skeletons for composites based on refractory particles with a metal binder. The thermodynamics of the process has been highlighted. The criterion for deconsolidation is established and the mechanism has been described.
Samsonov’s Model for Electronic Mechanism of Sintering and its Relevance
Authors: Upadhyaya Gopal S.
Published: August 2009

In the present review a generalized view of sintering mechanism on the basis of the electronic nature of the chemical species involved has been highlighted. The stable electronic configuration model proposed by G.V.Samsonov is one of the models. In spite of the fact that the model is qualitative, its far reaching impact in explaining liquid phase sintering and activated sintering of real systems can not be minimized. In a way the model holds a premium in its predictive nature , which is so crucial not only in sintering processing, but also in alloy design based on metallic or ceramic systems or composites constituted out of these.