bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Ultra-Strength Mortar Prepared with Mineral Admixture
Authors: Jin Zu Quan , Zhang Peng , Zhao Tie Jun , Hou Bao Rong
Published: February 2011

In this paper, preparation, property study of ultra-strength mortars with mineral admixture and clear river sand was carried out. The mineral admixture include fly ash, ultra-fine GGBS and silica fume. The experimental results show that the compressive strength of mortar improves with increasing amount of silica fume or ultra-fine GGBS. When the content of silica fume or ultra-fine GGBS is 30~35%, the compressive strength and flexural strength of mortar in curing age of 7 days are 100 MPa and 20MPa, respectively. But strength of mortar decreases with the increase replacement rate of fly ash. When the mortar mixes with combined of silica fume and ultra-fine GGBS, the optimum proportion of siliaca fume to ultra-fine GGBS is 2:3. And the compressive strength of mortar in curing age of 7 days is 75~100MPa when the mixed mineral admixture is 40~60%. The compressive strength of mortar is about 90MPa as it mix 60% of cement, 15% of silica fume, 15% of GGBS and 10% of fly ash. Moreover, the ultra strength mortar refines its pore structure and its capiliary pore (≥100nm) amount reduces by 78% compared to ordinary mortar.
Monodisperse, Luminescent Silica Spheres Synthesized by a New Method
Authors: Pan Wen , Wang Ning Hui , Li Guo Feng , Ning Gui Ling
Published: February 2011

The novelty of the current work lies in the simple synthesis of a new class of monodisperse, luminescent silica spheres produced upon calcination of hybrid amine-functionalized silica spheres which can known the role of ethylenediamine (en) on the morphology and luminescence properties of the resultant silica spheres.
Growth Spindle-Like ZnO Nanocrystalline Thin Films on Nickel Layers by Dc Magnetron Sputtering and its Thermal Annealing Properties
Authors: Wu W. , Xiao X.H. , Peng T.C. , Jiang C.Z.
Published: February 2011

A novel spindle-like zinc oxide (ZnO) nanocrystalline thin film was successfully fabricated on Ni thin film layer by ultrahigh-vacuum dc magnetron sputtering. Then the as-grown films were annealed in air at various temperatures from 673 to 1073 K, the corresponding structural features and surface morphology were studied by X-ray diffraction (XRD) and field emission scanning electronic microscopy (FE-SEM). The results reveal that the dominant direction of grains movement changed from perpendicular to parallel to the film interfaces. A correlation of the band gap and photoluminescence (PL) properties of nanocrystalline ZnO films with particle size morphologies and strain was discussed. Especially, PL emission in UV range, which is due to near band edge emission is more intense in comparison with the green band emission (due to defect state) was observed in all samples, indicating a good optical quality of the deposited films.
The Enhanced Magnetoresistance Effect of La0.67Sr0.33MnO3 with Pentavalent Ions Addition
Authors: Huang Bao Xin , Wang Jun Hua , Wang Zhen Hua , Chen Ke Zheng , Liu Yi Hua , Mei Liang Mo
Published: February 2011

The magnetic and electrical properties of La0.67Sr0.33MnO3 ( LSMO ) are influenced very much by the Nb dopant. However, this doping effect is restricted by the limited Nb solution into LSMO due to the low calcined temperature. As a result, a second phase LaNbO4 appears in our samples. Enhancements of the low-field magnetoresistance (LFMR) were observed both at 77 K and room temperature in the manganite system prepared by doping Nb2O5 into LSMO powders. The doping amount x of Nb ions ranges from 0-10 % molar ratio. The MR ratios at 77 K with H = 1 T and H = 0.1 T are 33.8 % and 24 % for the x = 0.07 doped sample, respectively. A MR effect up to 9 % was also found for the sample with x = 0.05 at room temperature, which is 2.2 times as large as that for LSMO (4.1%). The spin dependent tunneling and scattering at the interfaces of the grain boundaries are responsible for the LFMR while the high field magnetoresistance (HFMR) originates from the spin dependent transport related to noncollinear spin structure at the interfaces.
Determination of Refractive Indices and Linear Coefficients of Thermal Expansion for Development of Athermal Glass
Authors: Kobayashi Yoshinao , Shimizu Taiichi , Endo Rie , Susa Masahiro
Published: February 2011

Recently, there has been a growing importance of development of ‘athermal glass’ having no temperature dependence in its optical path length and is expected to be used in optical devices for the optical fibre transmission system. The athermal characteristic is usually evaluated by temperature dependence of optical path length, (1/l)･(dS/dT) ( l : geometrical length, S : optical path length, T : temperature), which is the summation of nα and dn/dT (n: refractive index, α: linear coefficient of thermal expansion). In the present work, the refractive index and liner coefficient of thermal expansion have been determined for silicate glasses containing titanium oxides in the temperature range from room temperature to about 673 K, using ellipsometry and utilizing the sessile drop method. The values of nα and temperature coefficient of n ranged from 1.289×10-5 K-1 to 3.345×10-5 K-1 and from 0.270×10-5 K-1 to 1.467×10-5 K-1, respectively, depending on the glass composition. Consequently, only 80SiO2-5TiO2-15Na2O glass has shown almost the same degree of athermal characteristic as SiO2 glass, having more advantages in practice due to its lower melting temperature than SiO2.
Microstructure and Wear Properties of TiC/7075 Composites by In Situ Reaction Liquidus Curve Casting Method
Authors: Xu Ping , Wang Feng , Liu Hui Min , Liu Xiang Dong
Published: February 2011

7075 matrix alloy was fabricated by in-situ reaction liquidus curve casting method, and its as-cast microstructure was analyzed, the wear properties of these composites and matrix alloy were studied under the different conditions. The results show that the wear resistance of TiC/7075 composites is superior to 7075 matrix alloy in the same conditions (with same load or rotating velocity). Because of introduction of particle reinforcements, the wear resistance of the composite is enhanced by 1.5～4 times than that of its matrix. In addition, the wear mass loss of TiC/7075 composites increases almost with increase of load, but decreases with increase of rotating velocity. The wear resistance of the composites increases slightly at low load and high rotating velocity. The SEM analysis of the worn-out surface indicates that the wear mechanism of TiC/7075 composites is mainly abrasive wear.
Piezoelectric Micromachined Ultrasonic Transducer with a Dome-Shaped Single Layer Structure
Authors: Peng Jue , Chao Chen , Tang Hu
Published: February 2011

Piezoelectric micromachined ultrasonic transducers (pMUTs) have been investigated as a promising new approach for ultrasound generation and reception. Most of the reported pMUTs employs a unimorph structure of a micromachined piezoelectric thin film on a silicon membrane. In this paper, a dome-shaped model for piezoelectric micromachined ultrasonic transducer (pMUT) was proposed to replace the conventional unimorph structure. A finite element analysis was carried out to study the elecro-mechanical behaviour of the dome-shaped model. The result showed that a considerable improvement of electro-mechanical coupling performance was achieved with the new model.
Phase Analyses of a TtPt Alloy Synthesized by Spark Plasma Sintering
Authors: Chikwanda Hilda Kundai , Yamabe-Mitarai Yoko , Chikosha Silethelwe
Published: February 2011

A Ti-50at%Pt alloy synthesized using the spark plasma sintering (SPS) technique has been characterized for phases’ identification. TiPt alloys have potential use as high temperature shape memory alloys(HTSMAs). Test specimens were prepared at SPS temperature of 1300°C. Sintering pressure and time were varied. The microstructural features of the specimens were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electron microscope used was equipped with an EDS detector, that, together with the XRD, were used for both the identification and analyses of the phases in the starting materials and the sintered alloys. High temperature XRD (800 -1300°C) as well as ambient temperature XRD analyses were done on the starting mechanically alloyed powders. All the samples tested at elevated temperatures were subsequently tested at room temperature after cooling. XRD analyses of the sintered samples were all done at room temperature. Analyses of the XRD results revealed new distinct phases from a temperature of 1000°C. A comparison of the room temperature XRD results for alloy powders and that of the sintered alloys was made. The following phases have been identified and studied TiPt B2, TiPt B19, Pt3Ti, Ti3Pt and Pt5Ti3. SPS pressure and sintering time did not show much effect on the phases detected. The alloy composition was found to be very inhomogeneous.
An Experimental Investigation of Mechanical Strength of Knotted NiTi SMA Fiber Composite
Authors: Zhao Yong Li
Published: February 2011

The paper presents a new design concept for evaluating the mechanical strength of unidirectional composite material with shape memory alloy (SMA) fiber in the presence of matrix crack. NiTi SMA fiber with both ends knotted is used to actively control the composite strength instead of straight fiber for purpose of better ensuring stress transfer from the matrix to the fiber. Experiment is conducted to verify the effectiveness of this new design concept.
VIMP Curing Process and Health Monitoring of Vinyl Ester Composites Based on Fiber Bragg Grating Sensors
Authors: Sun Jiu Xiao , Ji Yun Dong , Zhang Wei , Wang Ji Hui , Tong Xing Lin
Published: February 2011

In this paper, curing process monitoring of vacuum infusion molding process (VIMP) based on FBG for glass fiber reinforced vinyl resins was studied. In the experiment, three kinds of sensors were embedded in the composites. Excursion of the wavelength and temperature was tested in the whole curing process. Reflected power was tested by spectrometer in the molding process, the gel point was tested. In addition, 3-point bending test of composites which FBG was embedded in was done. Results showed that FBG could be exactly reflecting the relationship of stress and strain in bending state of composites.
Preparation of SiCw/Al2O3 Composite Sheets through Gel-Tape-Casting Process
Authors: Li Shao Chun , Zhang Peng , Zhao Tie Jun , Jin Zu Quan , Gao Song
Published: February 2011

In this paper, the gel-tape-casting process was applied to manufacture multilayer green sheets of SiCw /Al2O3 composite. The influence of SiCw, ball milling time and solids loading on the rheological behaviors of SiCw/Al2O3 slurries were investigated. It was found that the slurries exhibited a shear thinning behavior. The viscosity of the slurry increased with increasing of the fraction of SiCw. A stable slurry with 40 vol.% solids loading was prepared when 20 vol.% of SiCw was added. The flexural strength of the green sheet showed a trend of increasing firstly and then decreasing with SiCw increasing. The optimal mechanical properties of 40.2 MPa for flexural strength was obtained when SiCw contents was 20 vol.%. SEM observation indicated that significant whisker alignment was present in the composite tape, which was considered as one of parameters affecting toughening process.
Preparation and Properties of the Organic-Inorganic Composite Coating on Aluminum Alloy
Authors: Li Guo Jun , Cui Xue Jun , Ren Rui Ming
Published: February 2011

The organic-inorganic hybrid sol was prepared using an alkaline silica sol modified by acid-catalyzed hydrolytic polycondensation of methyltrimethoxysilane (MTMS) in a water-bath condition of 60oC, and then the water-based primer and topcoat were prepared through adding the pigments and nano-TiO2 suspension respectively. Through spraying and baking, the organicinorganic composite coating on the treated aluminum alloy was obtained. The optimum range of P/B (weight ratio of the pigment/binder) is determined between 1:1 and 1.5:1 by investigating the influence of the P/B of the primer on the adhesion and impact resistance of the coating. The microstructure of the coating was characterized by optical microscopy and scanning electron microscopy. The results show that there are lots of holes and lamellar structure in the primer coating and the obtained topcoat coating is uniform, smooth and dense. The coating of ~30 μm in thickness is mainly composed of three elements of silicon, aluminum and titanium, in which transition layer of ~10 μm is included. The physicochemical properties suggest that the coatings on aluminum alloy can meet the needs of finishing coating very well.
Enhanced Surface Properties Induced by High Current Pulsed Electron Beam (HCPEB) Treatment
Authors: Hao Sheng Zhi , He Dong Yun , Li Min Cai , Xu Yang , Dong Chuang
Published: February 2011

High current pulsed electron beam (HCPEB) has been developed as a useful tool for surface treatment of materials. In the present work, the fundamental principle of HCPEB source was described along with the device configuration and working parameters. Through the different kinds of HCPEB surface treatment experiments conducted, the enhanced surface properties induced by HPCEB treatment were illustrated and explained with their microstructure characterization results.
ZrC-Zr2Si Coating on Carbon Fiber Reinforced Silicon Carbide Matrix Composites Prepared by Pack Cementation Method
Authors: Xiang Yang , Wang Song , Chen Zhao Hui
Published: February 2011

ZrC-Zr2Si coating was prepared on carbon fiber reinforced silicon carbide matrix composites (C/SiC) by pack cementation method to prevent these composites from oxidation. SEM, EDS and XRD were applied to analyze the surface and cross-section morphologies, element distribution and phase composition of the coating, respectively. The results show that the coating made by the technique exhibits excellent oxidation resistance. The optimizing infiltration composition and process was: 60wt.%Zr-Si, 30wt.%PCS-DVB, 10wt.%Al2O3, holding 8 hours at 1400°C in Ar protecting atmosphere, ZrC-Zr2Si coating is obtained, homogeneous and density. The weight loss percentage of the coated C/SiC is only 1.52％after oxidation in air at 1500°Cfor 30min.
Performance Improvement of TiO2/Ti Composite Photocatalyst Film by Heat Oxidation Treatment
Authors: Lu Yun , Yoshida Hiroyuki , Toh Keisuke , Hao Liang , Hirohashi Mitsuji
Published: February 2011

In the present work, heat oxidation treatment was carried out for improving the photocatalyst activity of TiO2/Ti composite film. The microstructures and photocatalytic activity of the composite film were investigated. Effect of heat oxidation treatment was discussed. The results show that crystallinity of TiO2 in the composite film was improved by heat oxidation treatment. The photocatalyst activity was increased owing to the improvement of TiO2 crystallinity by heat oxidation treatment.
Erosion Wear Resistance of TiAlCrN Coating on Stainless Steel Impacted by Solid Particles
Authors: Wu Feng Fang , Deng Jian Xin
Published: February 2011

TiAlCrN coating was deposited on a stainless steel using unbalanced magnetron sputtering technique. The erosion wear resistance of the TiAlCrN coating was investigated by comparison with that of the TiN coating deposited by filtered vacuum arc deposition. SEM was used for observing the surface morphologies of coatings both the un-eroded and eroded. Scratch test was used to evaluate the adhesion of the coatings. The erosion wear was tested with a gas blast apparatus at room temperature. In the test, the coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the optical profiler was used to evaluate the erosion wear loss of the coatings. TiAlCrN coating proved to have much lower erosion rate than TiN coating. Unlike TiN coating, the TiAlCrN coating behaved like semi-brittle material.
Relationship between Structure and Functional Properties of the ZnO:Al Thin Films
Authors: Yue Hong Yun , Wu Ai Min , Hu Juan , Zhang Xue Yu , Li Ting Ju
Published: February 2011

ZnO:Al thin films were deposited on glass substrates by r. f. magnetron sputtering. The crystal structures were characterized using X-ray diffraction. The electrical property and the light transmission of the ZnO:Al thin films were investigates utilizing Hall system and UV/Vis/NIR spectrophotometer. The results show that the ZnO:Al thin films prepared with the sputtering power of 100W, working pressure of 0.3Pa and substrate temperature of 250°C have the resistivity as low as 3.1×10-3Ω⋅cm and transmittance over 90% in visible region. From the GIXRD patterns, higher electrical conductivity is related to the higher ratio of I2 (103)/I(002), which is a new reasonable structure parameter to estimate the electrical property of ZnO:Al thin films.
Effect of Gas Temperature on the Particle Deposition Characteristics and Coating Microstructure by Cold Spray
Authors: Meng Xian Ming , Zhang Jun Bao , Liang Yong Li , Han Wei , Zhao Jie
Published: February 2011

In this study, 304 stainless steel particles were deposited on IF steel substrates by cold dynamic spray technology. The effect of gas temperature on bonding features and deposition critical velocity were studied and compared. The results demonstrated that the successful bonding between 304SS particle and substrate could be attributed to the adiabatic shear instability mechanism, increasing gas temperature led to enhance the particle interface bonding, deduce the deposition critical velocity, and also increase both deposition efficiency and density of coatings.
Effects of CaB2O4 Content on the Sintering Behavior of Hexagonal Boron Nitride
Authors: Cao Yu Xia , Du Ling Zhong , Zhang Wei Gang
Published: February 2011

CaB2O4 was added into hexagonal boron nitride (hBN) to improve the sintering behaviors of hBN. CaB2O4 and hBN were mixed and then pressed into plates. The plates were sintered at 2000°C for 5h under a N2 ambience. The phase compositions with different CaB2O4 contents were examined with X-ray diffraction analysis. The fracture cross-sections of the hBN plates were investigated by SEM. The apparent density and Rockwell hardness were also measured. The results show that the hBN particles had a plate-like shape and the grain sizes of hBN increased with increasing CaB2O4 contents. The apparent density and Rockwell hardness decreased with increasing CaB2O4 contents. When the CaB2O4 content was 15(wt) %, the hBN has the average grain sizes of 3μm in diameter and 200nm in thickness, the apparent density of 1.06 g/cm3 and the Rockwell hardness of 3, respectively.
Pozzolanic Activity of Ceramic Polishing Powder as Cementitious Material
Authors: Wang Gong Xun , Xu Kui Jun , Zhu Ming Qiao , Tian Bi
Published: February 2011

The major industrial by-product largely generated in southern China is ceramic polishing powder (PP) produced from ceramic industries. In this paper, gross of silicon and aluminum dissolved from polishing powder and fly ash were studied by alkali dissolve experiments, pozzolanic activity of PP and fly ash were studied as well by determining chemical combined water and fast strength experiments. Results show that the cement mortar strength active index of PP is up to 82%. The average size of PP is 6.31 um; the fine granule of PP fills in the pore of mortars and improves the compressive strength of mortars. Microstructure of mortars added PP demonstrates that hydration gel is close-grained, dense and reticular. It reveals that “the granule domino effect” enhance the density of mortars added PP and conduce to the high compressive strength. Polishing powder can be used as cementitious material, especially the quality of early stage is higher than that of fly ash. Gross of vitreous phase is not the single factor to determine pozzolanic quality of polishing powder, ability of alive silicon and aluminum responding to Ca(OH)2 is one of the most important impact.
Mechanical Properties and Microstructure of KD-1 SiCf/SiC Composites Fabricated by Vapor Silicon Infiltration
Authors: Wang Hong Lei , Zhou Xin Gui , Cao Ying Bin , Yu Jin Shan , Liu Rong Jun
Published: February 2011

Continuous silicon carbide fiber reinforced silicon carbide matrix (SiCf/SiC) composites were fabricated by a combining polymer impregnation and pyrolysis (PIP) and vapor silicon infiltration (VSI) process. The mechanical properties and microstructure of the SiCf/SiC composites were studied. The results show that the open porosity of the SiCf/SiC composites is near zero. The density and mechanical properties of SiCf/SiC increase with decreasing the porosity of SiCf/C. However, the SiC fibers are damaged during the VSI process due to the reaction between SiC fibers and vapor Si.
Effects of Carbon Source on Fabrication and Characterization of Porous Silicon Nitride Ceramics by Carbothermal Reduction
Authors: Yang Shu Wen , Shan Shao Yun , Ma Wen Hui , Wang Hua
Published: February 2011

Porous silicon nitride ceramics with high-porosity were fabricated by carbothermal reduction reaction between silicon dioxide and carbon. The influences of carbon sources on microstructure and phase composition of the samples were studied. The result showed that the resultant porous silicon nitride ceramics using nano-meter carbon powder (C(n)) had finer microstructure, more uniform pore structure than those using activated carbon powder (C(a)). In order to illuminate the reaction and growth mechanism of b-Si3N4 grains, a series of intermediate sintering processes were investigated. X-ray diffractometry showed a difference in phase composition for the samples using the different carbon sources.
Densification of Alumina Ceramics by Infiltration of a Nano-Sized Alumina Sol into Alumina Green Samples
Authors: Jiang Shu Wen , Ning Gui Ling
Published: February 2011

Infiltration of a nano-sized alumina sol into the green bodies is proposed to facilitate the ceramic sintering. The green samples were prepared by a colloidal processing based on drying induced forming, and then were immersed in a nano-sized alumina sol prior to their sintering at 1350-1600 oC. The alumina sol was characterized by using transmission electron microscopy and the grain structure of sintered alumina ceramics were examined by scanning electron microscopy. Significant densification of sintered samples was evidenced, in a depth of ~ 0.5 mm, on the samples treated with the alumina sol infiltration. It is indicated that filling of nano-sol into the micro-pores between particles of green samples enhanced the sintering densification process. The infiltration treatment by nano-sol may also provide an effective way to produce structurally gradient ceramics with a gradual changing density and/or composition from the surface into bulk.
Thermodynamic Model and Synthesis of Bulk Metallic Glass in Cu-Zr-Ti System by Mechanical Alloying
Authors: Bhatt Jatin , Kumar Sundaram , Murty B.S.
Published: February 2011

Based on the thermodynamic and topological approach, Cu60Zr30Ti10 has been identified as the best bulk metallic glass forming composition in Cu-Zr-Ti system. Bulk metallic glass has been successfully produced using mechanical alloying of elemental blends and consolidation of the resulting glassy powders into pellets of 8 mm diameter. Dry sliding wear of glassy pellets at different annealed states showed that the relaxed metallic glass has excellent wear resistance.
Effect of Nb Addition on the Structural and Mechanical Properties of Cu46Zr42Al7Y5 Bulk Metallic Glass
Authors: Du Y.L. , Xu H.W. , Cheng J.L. , Chen Guang
Published: February 2011

In this work, the Cu46Zr42-xAl7Y5Nbx alloys with different Nb contents were prepared by water-cooled copper mold casting. The effects of Nb addition on the structural and mechanical properties were studied. It was found that the structure remains in amorphous state at low Nb concentration (x =1, 2). However, some crystalline phases appear in the high Nb content alloy (x > 2), showing a composite structure, that is, the second phase particles dispersed in an amorphous matrix. The effects of Nb on the glass-forming ability of Cu46Zr42Al7Y5 were studied by differential scanning calorimetric (DSC). The compressive mechanical properties of Cu46Zr42-xAl7Y5Nbx alloys were studied. It was found that the compressive strength can be improved by introducing Nb. However, the ductile of the alloys were not improved by the introduction of Nb.
Band Gap Widening and Quantum Confinement Effects of ZnO Nanowires by First-Principles Calculation
Authors: Guo Mei Li , Zhang Xiao Dong
Published: February 2011

ZnO nanowires are promising for photonic devices, biosensor and cancer cell imaging. We have performed a first-principles study to evaluate the electronic and optical properties of ZnO nanowires. We have employed the Perdew–Burke–Ernzerhof form of generalized gradient approximation in the frame work of density functional theory. Calculations have been carried out at different configurations. With decreasing diameter, the band gap of ZnO nanowires is increased due to the increase of quantum confinement effects. The results of imaginary part of the dielectric function indicate that the optical transition between valence band and conduction band has shifted to the high energy range as the diameter decreases. The ZnO nanowires show size-tunable optical properties.
Application of Scanning Confocal Electron Microscopy to Nanomaterials and the Improvement in Resolution by Image Processing
Authors: Zhang X. , Takeguchi Masaki , Hashimoto Ayako , Mitsuishi Kazutaka , Shimojo Masayuki
Published: February 2011

Scanning confocal electron microscopy (SCEM) is a novel technique for threedimensional observation with a nanometer-scale resolution. Annular dark field (ADF) SCEM imaging has been demonstrated to have better depth resolution than bright field (BF) SCEM imaging. However, the depth resolution of ADF-SCEM images is limited by the vertical probe size determined by spherical aberration and convergence angle. Therefore, we attempted to employ a deconvolution image processing method to improve the depth resolution of SCEM images. The result of the deconvolution process for vertically sliced SCEM images showed the improvement in the depth resolution by 35-40%.
Simulation of Nano-Indentation of Nano SiC Ceramic Micro-Component
Authors: Zhang Ke , Ren Ju Ping , Liu Guo Zhi , Tang Yu Lan , Wu Yu Hou
Published: February 2011

A 3D model of molecular dynamics for nanoceramic SiC is adopted to simulate the hot pressing sintering and preparation process of SiC, and mechanical properties such as density, hardness and elastic modulus are calculated. Finite element model of indentation is established based on the mechanical performance parameters from MD simulation. Conical indenter is adopted in indentation simulation. The FEM simulation results show that: Maximum equivalent stress appears at the place of indenter tip, and equivalent stress curves are appeared hemispherical. As indentation depth increases, the stress increased. As the distance of away from the indenter increases, the displacement in equivalent displacement nephogram gradually decreased until zero. During unloading process, elastic restitution is occurred. The elastic restitution in the area of below the indenter is obviously. Residual stress in the center of indentation is maximal after unloading.
Mechanochemical Polymorphic Transformation of Photocatalyst Material TiO2 and its Dependence on the Milling Operation
Authors: Mi Guo Min , Saito Fumio
Published: February 2011

Some dry and wet grinding experiments have been respectively conducted on titanium dioxide which is a noble photocatalyst material in a mortar, a tumbling mill and a planetary mill. Anatase is apt to transform to rutile via a metastable phase brookite in every kind of mills in the case of dry grinding. And it hardly takes place for phase transformation from rutile to other forms. It is shown that the kind of mill has not decisive effect on the mechanochemical polymorphic transformation of titanium dioxide, which merely influences the rate of phase transformation. On the other hand, the addition of other liquid media, such as water and acetone, is helpless for phase transformation of anatase. Only anatase can transform to metastable phase brookite by wet grinding. When ground titanium dioxide is heated, the amorphous phase is easier to transform to rutile than metastable phase brookite at lower temperature.
Synthesis and Characterization of Andalusite/Polyaniline Composites
Authors: Shao Liang , Qiu Jian Hui , Liu Ming Zhu , Feng Hui Xia , Zhang Guo Hong , Zhao Yang , Lei Lin , Qin Li Jun
Published: February 2011

New types of conducting composites using andalusite as an inorganic substrate and polyaniline as the conducting phase were prepared. The composites exhibited conductivities in the 0.14-2.08 S/cm range, depending on the amount of polyaniline. The thermal stability of andalusite/polyaniline composites were studied by thermogravimetric analysis. The resulting composites were also characterized by using FTIR spectroscopy and scanning electron microscopy.
Bio-Medicine Coating on Surface of Magnetic Nanoparticles and its Safety Evaluation
Authors: An G. , Ju Dong Ying , Bian Pei , Kumazawa T. , Okasabe M.
Published: February 2011

The composite magnetic nanoparticles of coated SiO nano film with about 8 nm size can be dispersed in various liquid media, widely known as magnetic fluids or ferrofluids with both magnetic and liquid properties. In this paper, a bio-medicine coating technology on surface of magnetic nanoparticles and the optimum fabrication condition and the magnetism of composed bio-nanoparticles are investigated. Through observation of micro-structure of the bio-nanopaticles on coating surface, and evaluation of magnetic property and safety to apply to biomaterials, we know the bio-medicine coated on surface of magnetic nanoparticles is suitable of bio-solutions into surface of biomaterials.
Synthesis and Characterization of a Novel Biomaterial for the Conservation of Historic Stone Buildings and Sculptures
Authors: Liu Qiang , Zhang Bing Jian
Published: February 2011

The conservation of historic stone sculptures and buildings is a focus of research. But there are no completely satisfying protective materials until now. In this paper, a conservative film of apatite has been prepared on the surface-modified marble stone by using a solution of CaCl2 and (NH4)2HPO4 as the precursor through a biomimetic method. The prepared material was characterized by some instruments. Its performances were also evaluated by its ability to consolidate, resist soil and acid. The obtained results indicate that the conservative effects are satisfying and the biomimetic synthesis should represent a new prospective in stone conservation.
Chemically Modification to Corn Stalk as a Natural Material for Oil Absorption
Authors: Gao Yuan , Li Shuai , Qu Ping , Bai Lu , Zhang Li Ping
Published: February 2011

A series of natural materials used for oil absorption based on corn stalks have been prepared by acylation grafting with propionic anhydride in a solvent-free system at 100 and 140 °C for 2-6 h. It is found that the oil (benzene) sorption capacity of the grafted corn stalks is about 8.5- 12.6g/g (in 15 minutes), and the grafted material is significantly more hydrophobic than the raw corn stalks. The grafted corn stalk float on the surface of water, as the oil, can be easily to be removed when the application is completed. Fourier infrared (FT-IR) analysis is used to confirm the chemical reaction which takes place between corn stalks and propionic anhydride. Scanning electron microscope (SEM) analysis is used to determine the structure of the grafted corn stalk material.
Amorphous Ni-Co-B Catalyst for Hydrolysis of NaBH4 in Alkaline Solution
Authors: Wu Chuan , Bai Ying , Wu Feng , Liu Dan Xian
Published: February 2011

Amorphous Ni-Co-B catalyst was synthesized by a chemical reduction method, and followed by a heat-treating at 100°C, then characterized by X-ray diffraction (XRD), Scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmetr-Teller (BET) analysis, and adopted to help accelerating hydrolysis reaction of NaBH4 alkaline solution. It is proved that the amorphous Ni-Co-B catalyst is not a simple combination of elemental Ni, Co and B, but a multiplex metal boride. It exhibits an maximum hydrogen generation rate of 210 ml/min/(g catalyst) at 100% H2 utilization, which is potentially to give a successive H2 supply for proton exchange membrane fuel cells.
Effects of Fiber Orientation Angles and Fluctuation on the Tensile Properties of Sliver-Based Green Composites
Authors: Ren Bao Sheng , Noda Junji , Goda Koichi
Published: February 2011

This paper describes an effect of fluctuation in fiber orientation on the tensile properties of sliver-based green composites. The composites were reinforced with slivers of high-strength natural fibers extracted from plants named curaua. Then a surface optical micrograph of the composites with the fiber fluctuation was obtained. The micrograph was divided into many fine segments, and the fiber orientation angle in each segment was measured. Results show that the tensile strength depends on autocorrelation coefficients expressing the degree of fluctuation in fiber orientation, as well as the fiber orientation angles. However, the Young’s modulus was dependent only on the angles, rather than on autocorrelation coefficients. In addition, a statistical concept was applied to an orthotropic analysis for prediction of the Young’s modulus. The predicted Young’s moduli showed better agreement with the experimental results.
Effects of Hydrophilicity/Hydrophobicity of a Drug on its Release from PLGA Films
Authors: Liu Hong Ze , Qi Min , Guo Bo , Liu Hui Hua
Published: February 2011

Hydrophilic ciprofloxacin hydrochloride and hydrophobic sirolimus were used as model drugs, and poly(dl-lactic-co-glycolic acid) 50/50 (PLGA 50/50) was used as the drug carrier to investigate the effects of hydrophilicity/hydrophobicity of a drug on its release properties from PLGA films. The results showed that ciprofloxacin hydrochloride induced faster release curves than sirolimus, and it also promoted the weight loss of films, while sirolimus inhibited the weight loss of films. However, both drugs inhibited the degradation of biodegradable carrier.
Calcium Evaporation from Metallurgical Grade Silicon by an Electron Beam Melting
Authors: Dong Wei , Peng Xu , Jiang Da Chuan , Tan Yi , Wang Qiang , Li Guo Bin
Published: February 2011

In order to investigate Ca evaporation behavior in the electron beam melting process, metallurgical-grade silicon was melted in an electron beam furnace with different experimental conditions. The results showed that the content of impurity Ca was significantly decreased in the early time, while these changed slowly with the extension of the melting. The removal rate of Ca was controlled by the transfer of Ca atoms from the bulk liquid silicon to liquid/gas phase interface within the range of experiment temperature.
Study on Compressed Wood with Urea-Formaldehyde Prepolymer
Authors: Wu Guo Feng , Jiang Yi Fei , Qu Ping , Yao Sheng , Pu Jun Wen
Published: February 2011

In this research, the urea-formaldehyde prepolymer and multilayer hot-press drying was used to obtain modified wood. The timbers were compressed and dried by the multilayer hot-press drying kiln. The combination of chemical modification and hot-press drying can improve the drying rate, which can also enhanced the physical and mechanical properties. Based on the findings, the basic density of modified wood improved 25.2 %, the bending strength and the bend elastic modulus improved 15.6 % and 25.0 % respectively. The dimensional stability of the treatment appeared to be slightly higher than that of untreated samples under the same conditions for processing temperatures and times. The improving dimensional stability of wood mainly was attributed to the prepolymer that changes wood cell wall components such as the degradation of the hemicelluloses and cellulose during hot-press drying treatment. The XRD results indicated that the degree of crystallinity increased to 35.45 %from 31.25 %. The TGA results show that the degradation of the samples can be divided into two step, both of the maximum weight loss velocity temperature of the two step increased to 266 °C, 355 °C from 244 °C and 341 °C.
Experimental Research on the Durability of WPC Wallboard Made of Paper-Aluminum-Plastics Wastes
Authors: Gao Song , Li Qiu Yi , Sun Cai Xia
Published: February 2011

Waste Paper-Al-Plastic materials including Tetrapak beverage and milk boxes are used to extrude the WPC instead of normal wood fiber material in this research. As many WPC products are applied as exterior wallboard at present, the research on the durability and flame retardancy of Wood-Plastic Composites is important. In this paper, various durability influences and flame retardancy of WPC are analyzed in the laboratory conditions. Some experimental results are presented as follow: Water absorption of WPC is influenced by immersion time. After immersion of simulated acid rain solution and alkali environment, and accelerated ultraviolet radiation tests, WPC samples are observed with banding strength decrease. Nonetheless, the performances of WPC wallboard achieve the requirements of national code when it is properly provided with anticorrosion coating systems. Oxygen index of 27 indicates that WPC is inflammable material. Zinc borate (ZB) and ammonium polyphosphate (APP) are effective flame retardant for Paper-Al-Plastic WPC.
Effect of Lumen Size on Transverse Thermal Conductivity of Unidirectional Natural Fiber-Polymer Composite via Finite Element Method
Authors: Liu Ke , Takagi Hitoshi , Yang Zhi Mao
Published: February 2011

In order to evaluate the effect of natural fiber lumen size on the transverse thermal conductivity of the unidirectional natural fiber-polymer composite, a two-dimensional unit cell model of natural fiber-polymer composite was studied using finite element method (FEM). In this study, the FE cell model was kept in the steady state thermal condition. The results showed that the effective transverse thermal conductivity K has a relationship with the geometrical ratio (α, 0<α<1) of lumen radius (rl) to fiber radius (rf). When the lumen size ratio α is small, K increases with increasing fiber volume fraction Vf, while K decreases as the Vf increases when α is large. It indicates that the thermal property of composites changes with fiber’s lumen size. When a composite is designed for thermal insulation material, we should choose the natural fiber with large lumen, and to design thermal conductive composite, small lumen size should be used. The result from present method was compared with experimental data and shows a good agreement.
Research on Polypropylene Electret Melt-Blown Nonwoven Doped with Nano-Tourmaline
Authors: Kang Wei Min , Cheng Bo Wen , Jiao Xiao Ning , Liu Ya , Ren Yuan Lin
Published: February 2011

Electret filter composed of permanently charged electret fibers is a good material for environmental protection. A novel kind of electret melt-blown nonwovens (EMNs) doped with nano-tourmaline was developed by corona charging in this paper. The structure of web, mechanical properties, surface charge density and filtration efficiency of samples were discussed. The results showed that the structure of EMNs became loose and the initial surface charge density was increased markedly. Furthermore, the EMNs exhibited higher filtration efficiency and lower pressure drop, especially the content of nano-tourmaline was about 6 wt. %.
Removal of Phosphorus in Metallurgical Grade Silicon Using Electron Beam Melting
Authors: Dong Wei , Wang Qiang , Peng Xu , Tan Yi , Jiang Da Chuan
Published: February 2011

The effects of melting condition on the dephosphorization behavior in metallurgical grade silicon (MG-Si) by electron beam melting (EBM) were investigated in this study. Experiment results showed that phosphorus content decreased by evaporation with the increase of melting time, and evaporation rate increased with the increase of electron beam power. Phosphorus content decreased to below 0.1 ppmw by EBM treatment at 21 kW for 1800 seconds. The dephosphorization reaction was found to follow the first order kinetics. Dephosphorization rate was controlled by free evaporation.
Study on Direct-Weld between Bakelite and Aluminum
Authors: Qiu Jian Hui , Zhao Yang , Yamamoto Taku , Zhang Guo Hong
Published: February 2011

Recently in electronic and automobile industry, polymer materials were selected to replace metals in many products because of miniaturization and weight reduction. So the weld between polymers and metals became very important. Currently, the ways were limited to adhesive joint or the mechanical weld which both had obvious defects. In this paper, the direct-welding methods were studied and the welds based on compress-molding were viable and useful. The welding strength enhanced because the reaction between polymers and modified metals were confirmed.
Develop Flexible Piezoelectric PVDF Nano-Fibrous Membrane
Authors: Wang Yong Rong , Zhang Pei Hua , Xu Chun Ye
Published: February 2011

Piezoelectric polymer, polyvinylidene fluoride (PVDF) film, has been widely investigated as sensor and transducer material due to its high piezo-, pyro-, and ferroelectric properties. However, there are many limitations for PVDF film as human-related tactile sensor, such as non-breathability, stretching, requirement of additional process like poling, etc. In this paper, PVDF nano-fibrous membrane which is light, flexible, and wearable was prepared by electrospinning technique. The electrospinning parameters such as the voltage, feeding rate, tip-tocollector distance, etc, were well controlled. More than 4 hours electrospinning time was needed for a certain thickness of PVDF nano-fibrous membrane. The morphology of PVDF nanofiber was determined by scanning electron microscopy (SEM), the diameter distribution was calculated and crystal structure was evaluated by FTIR spectroscopy. We found the feasibility of developing piezoelectric PVDF fibrous membranes through electrospinning technology, which is a good candidate for flexible human-related tactile sensors to sense garment pressure, blood pressure, heartbeat rate, accidental external impact on human body, etc.
Experimental Study on Strength and Deformation of Brittle Rock under Different Compression Condition
Authors: Zhou Jia Wen , Yang Xing Guo , Li Hong Tao
Published: February 2011

This paper studies on the characteristics of strength and deformation of brittle rock under different compression condition by experimental tests. A lot of experimental tests for the Xiangjiaba sandstone are carried out under different compression condition, including uniaxial compression, triaxial compression, uniaxial monocyclic compression and uniaxial loading and unloading. Base on the experimental test results of the Xiangjiaba sandstone, the strength and deformation of brittle rock are analyzed, and some comparative analysis for the mechanics characteristics of brittle rock are carried out. The compute results show that, the peak strength of brittle rock is increased with the confining stress, and close to a linear relationship. Its also show that, the peak strength is not increased under the monocyclic compression, neither for the loading and unloading condition.
Molecular Imprinting: Mimicking Molecular Receptors for Antioxidants
Authors: Pardeshi Sushma , Kumar Anupama , Dhodapkar Rita
Published: February 2011

Molecularly imprinted polymers (MIPs) have been demonstrated to be a promising class of biomimetic materials that can be tailored to meet specific end use recognition requirements. Molecular imprinting is achieved by the interaction, either covalent or non-covalent between complementary groups in a template molecule and functional monomer units through polymerization. MIPs have been widely employed for divers applications such as chiral separation, chemical sensing, catalysis, drug screening, chromatographic separations and solid phase extraction. During respiration and metabolism, human body produce free radicals as by products, which can damage genetic material, lipids and proteins leading to several fatal diseases such as Cancer, Cardio-vascular disease, Alzheimer’s disease, Immune dysfunction etc. Antioxidants define a family of natural or synthetic nutrients in food, which acts as free radical scavengers. They are present in complex matrix such as herbs, fruit pulp in small concentration, either combined or in free form. Although several techniques have been developed for their detection, (e.g. HPLC, Thin layer chromatography, Capillary gas chromatography, Supercritical fluid chromatography), to achieve highly specific and sensitive analysis, high affinity, stable and specific recognition agents are needed. In this review, special attention is paid to the MIPs based analytical methods for antioxidants, focusing on solid phase extraction, chromatographic and non chromatographic separations and sensing approaches as well as on novel approaches for the discovery of new imprinted materials for antioxidants.
Effect and Microscopic Mechanisms of Slag Micropowder on the Reinforcement of CaCO3 Whisker in Cement Composites
Authors: Wei Jian Qiang , Cao Ming Li
Published: February 2011

Whisker pull-out, which indicates that the interfacial bond strength of whiskers/cement is not high enough, is dominant in the microstructure of whisker-reinforced cement fractured surfaces. The weak interfacial bond of whiskers in cement matrix severely restrained the further improvement of properties. Superfine slag powder was used to modify and improve the strength and bond behavior of whisker-reinforced cement. Crystal structures, microcosmic appearances and characterizations of Slag Micro powder and the composite were studied by X-ray diffraction (XRD), and scan electron microscope (SEM/EDS), etc. Effect and mechanisms of different Slag powder content on the micro-structure and macro-properties of cement composite were investigated. The results show that Slag Micropowder can modify and improve the microstructure, interfacial and mechanical properties of whisker-reinforced cement.
Preparation of Chloride Ion Selective Electrode and its Potential Response to Different Chloride Solutions Representing Concrete Environments
Authors: Gao Xiao Jian , Zhang Jian , Yang Ying Zi , Lu Shuang
Published: February 2011

Ag/AgCl electrode was made from anodized Ag wire and the influence of anodization current density on stability of Ag/AgCl electrode was studied in this paper. Potential response of Ag/AgCl electrode was tested in synthetic concrete pore solutions with different concentrations of chloride ions and influences of sulfate, calcium, potassium and sodium ion on the potential response of Ag/AgCl electrode were also measured. The results show that Ag/AgCl electrode has the best potential stability when it is prepared with 0.4 mA/m2 of current density for 2 hours and there is no measurable potential difference among 20 electrodes prepared with such anodizing condition. The potential of Ag/AgCl electrode develops to a constant value in less than 60 seconds and maintains stable during the test period when immersed into synthetic concrete pore solution with different amount of chlorides. Ag/AgCl electrode shows a good linear potential response to a wide range of chloride concentrations from 0.005 to 1.0 M. Sulfate, calcium and sodium ions show inconsiderable influences on the potential of Ag/AgCl electrode. Therefore, it is suggested that Ag/AgCl electrodes can be used as chloride sensors in concrete exposed to different environments.