bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Structural Design and Capacitance Characteristics of Fabric Sensor
Authors: Zhang Ru Quan , Li Jian Qiang , Li De Jun , Xu Jing Jing
Published: February 2011

In response to the problem for non-washable and poor taking comfortable characterizations of smart electronic fabrics at present, two different organizational structures of fabric sensors with plain weave and double weave are designed. The basic principle of design of fabric sensor is: the core-spun yarn made of metal wire is used as core wire, the structural unit with capacitor function is built by interweaving warp with weft, and the induction of fabric to external pressure is reflected by testing changes in capacitance of fabric. The models of equivalent electronic circuits of two fabric sensors with plain weave and double weave are analyzed, and the relationships between area and capacitance characteristics of fabric sensor are discussed. The results show that: the larger the fabric area, the greater the capacitance, and the capacitance of 36cm2 fabric is maximum with 100Hz test frequency; under the condition of the same area and test frequency, the capacitance of plain weave fabric is greater than that of double-layer fabric under no pressure, but the increasing rate of capacitance of double-layer fabric is larger than that of plain weave fabric under the same pressure.
Characteristics of Hot Ductility and Fracture in Micro-Alloyed Q345B Structural Steel
Authors: Dong Fang , Su Cheng , Bai Yuan Yuan
Published: February 2011

Hot-ductility tests of the microalloyed Q345B structural steel were performed in a tensile machine of Gleeble-1500D at different strain rates of 1.5•10-3/s 、2.5•10-3/s and 2•10-2/s and at temperature range from 1300°C to 700°C(Δ T=100°C ), which are close to the continuous casting condition of steel. Fracture surfaces were examined using a scanning electron microscope; it was found that the hot decrease as strain rate decrease, because the void growth mechanism predominates over void nucleation, giving time for nucleation cracks to grow. The minimum ductility was found at about 800°C for the strain rates of 1.5•10-3/s and 2.5•10-3/s, and the fracture was intergranular. The steel has good plasticity in temperature range from 1200°C to 900°C which is suitable for straighten operation.
Rheology and Thermal Properties of Polypropylene/Poly(phenylene Sulfide) Microfibrillar Composites
Authors: Wang Hong , Guo Jing , He Xi Yang
Published: February 2011

The polypropylene (PP)/ poly(phenylene sulfide) (PPS) in-situ microfibrillar composites were prepared by the melt blending technology using a single screw extruder. Maleic anhydride grafted polypropylene (PP-g-MAH) is used as the compatibilizer. The rheology was characterized on capillary rheometer, and thermal behaviors of the PP/PPS were investigated by DSC. The experiment results reveal that the melting PP/PPS composites conform to the law of Non-Newton and show typical shear-thinning behavior. The viscosity of PP/PPS composites is nearly independent of the PPS concentration at 270°С and 280°С , respectively. However, the contents of PPS have an influence on shear viscosity of the PP/PPS at 290С and 300°С . The DSC results exhibit that the crystallization temperatures (TC) of PP in the composites are higher than that of the pure PP, and the TC of PP increases slightly with increasing PP content in the composites. Moreover, the melting temperature of PPS in the composites decreases slightly with increasing PP content.
High Quality Al2O3-ZrO2-C Slide Gate Properties Adding Si-Fe Sintered by both Nitrogen and Carbon Monoxide Atmosphere
Authors: Liu Lei , Li Yong , Zhai Ya Wei , Xue Wen Dong , Chen Jun Hong
Published: February 2011

The Si-Fe (≤0.043 mm) fine powder was added to the Al2O3-ZrO2-C slide gate, and the influences of adding different Si-Fe contents (2wt%, 4wt%, 6wt%, 8wt%) are studied. Two different firing ways of nitridation and carbonazation atmosphere were used. The experimental results indicated that the addition of Si-Fe improve the physical and chemical properties of the slide gate, the performance is the best when the addition of Si-Fe is 6wt% and the properties of slide gate sintering in N2-flowing atmosphere is better than that in CO-flowing atmosphere. Si-Fe will react with nitrogen and generate Si3N4 in the N2-flowing atmosphere, while it will react with C or CO to produce SiC in CO atmosphere.
Study on High Performance Fe3Si-Si3N4-SiC Composite Preparation and its Application in Blast Furnace
Authors: Li Yong , Zhu Xiao Yan , Zhai Ya Wei , Wang Jia Ping , Xue Wen Dong , Chen Jun Hong , Sun Jia Lin
Published: February 2011

Excellent Fe3Si-Si3N4-SiC composites were successfully prepared with FeSi75 and SiC as main starting materials by nitridation reaction(at 1300°C for 8Hrs). The effect of ferrosilicon alloy addition amount on material properties was studied; the ferrosilicon nitridation mechanism was analyzed through chemical thermodynamics; phase composition, microstructure, alkali resistance of products were also investigated. The results show that when ferrosilicon addition amount is 12wt%, the comprehensive property of Fe3Si-Si3N4-SiC is the best. The nitridation products are fiber-like α-Si3N4 and rod-like β-Si3N4, which makes better mechanical behavior due to fiber reinforcement; a great deal of Fe3Si intermetallic compounds uniformly distribute in matrix, which is one of the products of Fe-Si nitridation and as a plastic phase forming in grain boundary optimizes the performance of products. Chemical thermodynamic analysis shows that the fiber-like α-Si3N4 is formed by SiO(g) and N2(g) reaction which also increases the rate of nitridation. Fe3Si-Si3N4-SiC material has good performance. Now it has been successfully applied to one 2000M3 domestic steel plant, the blast furnace operation goes well.
Electrical Conductivity and Electromagnetic Interference Shielding Effectiveness of Multiwalled Carbon Nanotubes Filled ABS Composites
Authors: Shen Hong Yin , Jiao Qing Ze , Zhao Yun , Li Han Sheng , Sun Zhe
Published: February 2011

Multiwalled carbon nanotubes filled ABS (ABS/MWCNTs) composites were prepared via a method combined solution-blending with hot-press forming. Fractured cross-sectional surfaces of the ABS/MWCNTs composites were analyzed by scanning electron microscopy showing that MWCNTs were dispersed homogeneously in the ABS matrix. The volume resistivity of these composites was also analyzed and the percolation threshold was obtained at low filler loadings about 1–3 wt%. The Electromagnetic interference (EMI) shielding effectiveness (SE) of ABS/MWCNTs composites was investigated in 100–1500 MHz. It was found that SE of the prepared composites strongly depended on MWCNT loading. The highest EMI SE reaching 36 dB was observed for ABS/MWCNT composites containing 15 wt% of MWCNTs at 760 MHz.
Electrochemical and Quantum Chemical Investigations of Tinidazole as Corrosion Inhibitor for Mild Steel in 3% HCl Solution
Authors: Zhang Lei , Zhang Sheng Tao , Li Xiao
Published: February 2011

The inhibition effect of tinidozole on the corrosion of mild steel in 3% HCl solution has been investigated through weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and quantum chemical calculations methods. The results show that tinidazole is an effective inhibitor for mild steel corrosion in HCl solution, and that the inhibition efficiency reaches a maximum value of 62% at the concentration of 400mg/L. Polarization measurement suggests that the tinidozole acts as mixed-type inhibitor. The Langmuir adsorption isotherm is proposed to interpret the interaction for the inhibitor molecule on metal surface. Furthermore, the quantum chemical calculation reveals that the adsorption of tinidozole is mainly concentrated around the imidazole ring.
Thermal Conductivity Polypropylene/Aluminium Nitride Composites
Authors: Ma Ai Jie , Gu Jun Wei , Chen Wei Xing
Published: February 2011

The polypropylene/aluminum nitride (PP/AlN) thermal conductivity composites were prepared by compression moulding method. Results revealed that the thermal conductivity of the composites were increased with the increasing AlN, and the thermal conductivity of composites was 1.84W/mk filled with 50vol% modified AlN. Both the tensile and impact strength of the composites increased firstly, but decreased with excessive addition of AlN. For given AlN loading, the surface modification of AlN exhibited a positive effect on the thermal conductivity. Meantime, the grafting of PP could increase the thermal conductivity of the composites compared with pure PP. And the addition of AlN did not change the crystal form of PP, but decrease the crystallinity of the composites.
Winding of High Performance Thermoplastic PPESK Composites Using on-Line Solution Impregnation and In Situ Consolidation
Authors: Li Wei , Gao Wei Jia , Chen Ping
Published: February 2011

A novel filament winding process technology has been realized which allows to combine on-line solution impregnation with in-situ consolidation for a kind of high performance thermoplastic, poly (phthalazinone ether sulfone ketone) (PPESK). This technology solved the common problem of impregnating a large number of slender filaments with a highly viscous polymer melt which usually existed in thermoplastic manufacturing. During the winding process, the high-quality carbon prepreg tapes were firstly obtained on-line by using solution impregnation method, and then an arc electric heater was utilized to ensure the adaptable preheating and processing temperature. With the help of heat and tensile force, the intimate interlaminar contact was achieved.
Study on Electron Beam Curing of APTES Functionalized MWNTs/ Epoxy Composites
Authors: Lu Yan Yan , Li Hua , Liu He Zhou
Published: February 2011

In this study, we prepared the 3-aminopropyltriethoxysilane (APTES) functionalized MWNTs/epoxy composites by electron beam (EB) irradiation process. The modified MWNTs were characterized with SEM-EDS and FTIR. The gel content and conversion rate of epoxide groups of the EB cured pure epoxy resin and the APTES functionalized MWNTs/epoxy composites were measured and discussed. And the mechanical properties of the EB cured composites were also characterized. With addition of 0.25wt% APTES functionalized MWNTs, the Vicker’s hardness of the EB cured composite increased 100.02% compared with pure epoxy.
Effect of Carbon Fiber Felt Pretreatment on Properties of Carbon Fiber Paper
Authors: Zhang Xue Jun , Pei Hao , Shen Zeng Min
Published: February 2011

Gas diffusion layer is a very important component in fuel cell, and carbon fiber paper is widely used as substrate of gas diffusion layer. This paper has developed one way to produce carbon fiber paper from carbon fiber felt with or without pretreatment. The properties and microstructure of carbon fiber paper were also stdied. The results show that the pretreatment of carbon fiber felt is helpful to prepare carbon fiber paper with good properties. The content of carbon derived from resin during pretreatment has effects on density, thickness, porosity, gas permeability, porosity and tensile streagth of carbon fiber paper. Carbon fiber paper made from carbon fiber felt with pretreatment has better interface adhension than that of carbon fiber paper made from carbon fiber felt without pretreatment. Carbon fiber paper was produced with thickness of 0.28mm, density of 0.43g/cm3, porosity of 77%, gas permeability of 2500 mL•mm/(cm2•hr•mmAq), specific resistance of 0.017Ω•cm and tensile strength of 18MPa, which is a promising materials for fuel cell electrode.
Effects of Cold Deformation on Microstructure and Mechanical Properties of Cu-0.35Al2O3(Y) Composite
Authors: Tian Bao Hong , Dai Yong Qiang , Zhang Yi , Liu Yong
Published: February 2011

Internal oxidation is one of the most common methods to produce in situ nano oxide particles dispersion strengthened copper base composite (ODSC) in powder industry. In this paper, a simplified internal oxidation method was proposed to prepare ODSC composite by using thin strip of Cu-Al alloy. The effects of the addition of rare earth element yttrium and cold deformation on the microstructure and mechanical properties, such as hardness and tensile strength, were investigated briefly. Results show that after 80% deformation, the crystalline grains of the composite matrix plastically deformed in elongated shape to a certain direction as banded fiber structure. The addition of trace element yttrium and cold information increase the hardness and tensile strength of the Cu-0.35Al2O3(Y) composite remarkably, respectively.
Surface Analyses of High-Temperature Oxidized In Situ Synthesized Ti-40Al-2.0C Composites
Authors: Wang Hui Gai , Wang Fei , Song Yan Pei , Wei Zun Jie
Published: February 2011

With the reaction between titanium (Ti) sponge, high purity aluminum (Al) and TiC/Al inter-alloy, non-consumable arc melting technique has been successfully used in situ synthesize Ti matrix composites of Ti-40Al-2.0C. The composites oxidized at 700~900°C for different time in static air. The influences of oxidation time and temperature to oxidation kinetics of composites were analyzed. The surface morphologies and components of the oxidation scales were examined by scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). The results show that the isothermal oxidation kinetic curves of composites mainly follow parabolic rate law. When the composites oxidized at low temperature for short time, the color of oxidation surface is olivine which is similar to the color of the matrix and the oxides exist in non-uniform mixture state of Al2O3 and TiO2. While the composites oxidized at high temperature for long time, the color of oxidation surface is deep yellow and the oxides are mainly columnar hexagonal TiO2.
Antibacterial Property of Chinese fir/TiO2 Composite
Authors: Huang Su Yong , Li Kai Fu
Published: February 2011

Small samples of Chinese fir/TiO2 Composite were prepared using sol-gel method and microwave assisted liquid phase deposition (MWLPD) method for the first time. Results of antibacterial test show that during a one year test the samples exhibited prominent, broad-spectrum and long-lasting antibacterial performance, but were also influenced by light exposure and temperature.
On the Improvement of Fiber Reinforced Concrete through Surface Modification of Polypropylene by Grafting Method
Authors: Chou L.H. , Lin L.K , Lee M.T.
Published: February 2011

Polypropylene (PP) fiber reinforced concrete is an important composite. In order to improve the mechanical properties of PP fiber reinforced concrete, polyacrylamide (PAM) was grafted onto the PP surface by the UV irradiation to enhance the hydrophilic property of PP in this study. IR spectra showed the existence of carboxylic acid functional groups on the treated PP surface. AFM images depicted that the treated PP surface had the lower height fluctuation, roughness, and had the acicular appearance. Contact angles of the treated PP were reduced in comparison with that of the original PP. All of these experimental results gave the evidences that PAM had been successfully grafted onto the treated PP surface. Furthermore, OM images depicted that the treated PP adhered to cement hydrate products (C-S-H) more tightly than that of the original PP did. We therefore expect that PP grafted with PAM can enhance mechanical properties of PP fiber reinforced concrete.
Interlaminar Fracture Toughness of Composite Laminate with Splicing Plies
Authors: Liang Li , Jia Pu Rong , Jiao Gui Qiong
Published: February 2011

Delamination is one of the important damage modes in the fiber-reinforced composite laminates. The interlaminar fracture toughness is the key parameter in delamination failure analysis of composites. The stress analysis by a finite element modeling has shown that the shear stress is very large near the ply splicing area. So the delamination failure is mainly dependent on the mode II fracture toughness. A new way of loading in tensile testing is proposed for the measurement of mode II fracture toughness. Specific specimen with splicing plies has been designed and used for the experiment. Testing study on the carbon-fiber-reinforced laminate with ply splicing was performed. Steady crack propagation has been seen by the tensile testing of the specimen. Mode II fracture toughness GIIC of the laminate has been determined by the experiment data analysis. The experiment and numerical analysis shows that the tensile testing for the measurement of mode II interlaminar fracture toughness is feasible.
Seismic Reliability Analysis of MDOF Systems Based on Odd Exponent Wavelet
Authors: Xiao Mei Ling , Ye Liao Yuan , Gao Chun Tao
Published: February 2011

This study proposed non-failure or non-disabled probability of structure suffering random dynamic load within given time. A wavelet method based on its conception was proposed for seismic dynamic reliability analysis of MDOF system：From the Duhamel integral of the dynamic structural response, the structure stochastic response was expressed as earthquake ground motion’s wavelet transform. The ground motion and structure responses were modeled as non-stationary random process using odd exponent wavelets. The first-passage failure criterion and maximum probability were employed to estimate the structural dynamic reliability. The primary advantage of the proposed method is that it does not need to calculate spectral moments from the power density function integral, which are usually difficult to obtain the analytical expressions.
Improvement in the Thermal Shock Resistance of Zirconia Ceramic by the Addition of Aluminium Titanate
Authors: Wei Heng Yong , Yu Li Xue , Wang Zhi Fa , Bu Jing Long , Ma Shu Long , Wang Yu
Published: February 2011

ZrO2-Al2TiO5 composite materials with high bending strength and good thermal shock resistance expansion were prepared using partially stabilized zirconia (Y-PSZ) powders coated with Al2TiO5 by co-precipitation method. The effects of Al2TiO5 content on the sintering properties, phase composition, microstructure and thermal shock resistance of the zirconia ceramic were investigated．The results show that the apparent porosity of the samples decreased and their bending strength increased with the content of aluminum titanate increasing from 0 to 8 wt%. The samples with 5 and 8 wt% aluminum titanate addtion have excellent thermal shock resistance. The results showed that the addtion of aluminum titanate could enhance the mechanical strength and improve the thermal shock resistance of zirconia ceramic. The XRD and SEM analysis results indicated that the propriety improvement is relative with the change of the microstructure and the increase of tetragonal ZrO2 phase in the composites.
Mechanical and Tribological Properties of PTFE Composites Filled with POB
Authors: Zhang Sha , Wang Shi Bo , Mao Yong
Published: February 2011

The POB/PTFE composites were prepared by blending-cold pressing-sintering-hot pressing method. Influence of POB content on mechanical and tribological properties of the composites was investigated. Worn surfaces were analyzed by scanning electron microscope (SEM). The results indicated that ball indentation hardness and compressive strength of POB/PTFE increase with increasing POB content in composites. Tensile strength, elongation and impact strength of POB/PTFE decrease with increasing POB content in composites. Friction coefficient of composites increases compared to PTFE. Wear resistance of POB/PTFE composites was improved with filling POB. The POB/PTFE composite incorporating 20% POB has best comprehensive mechanical properties. Wear mechanism of PTFE are abrasive wear. Wear mechanism of POB/PTFE composites mainly are fatigue wear and flaking.
Microstructure and Mechanical Properties of Al2O3/Tial In Situ Composites Doped with Cr2O3
Authors: Wang Fen , Xiang Liu Yi , Zhu Jian Feng , Li Dong , Wang Xiao Feng
Published: February 2011

Al2O3/TiAl composites were successfully fabricated by hot-press-assisted exothermic dispersion method with elemental powder mixtures of Ti, Al, TiO2 and Cr2O3. The effect of Cr2O3 addition on the microstructures and mechanical properties of Al2O3/TiAl composites has been characterized. The results show that the Rockwell hardness, flexural strength and fracture toughness of the composites increase with increasing Cr2O3 content. When the Cr2O3 content is 3.5 wt %, the flexural strength and the fracture toughness reach the maximum value of 658.7 MPa and 7.2 MPa•m1/2, respectively. The improvement of mechanical properties is firstly associated with a more homogeneous and finer microstructure developed by addition of Cr2O3; secondly, it is related to the increase of the ratio of α2-Ti3Al/γ- TiAl matrix phases.
Tensile Property of the Flax/Polyester Composites after Water Treatment
Authors: Wang Qiu Hong , Huang Gu
Published: February 2011

Flax fabric was woven and composites were produced by using the VARI technique with flax fabric as the reinforcement and unsaturated polyester as the matrix. Laminates with two, three and four layers were fabricated respectively. After saturated in the water for different durations of time (7, 14, 21 and 30 days), the tensile strength of the composites was tested. After being soaked in the water for 7, 14 and 21 days, the tensile strength of the two-layer composites was decreased. For the three and four layers specimens, the tensile strength was increased initially with water treatment for 7 and 14 days,and decreased for 21 and 30 days. Scanning electron microscopy (SEM) confirmed that it might be contributed to the thickness of the two-layer composites. The thinner specimen is easier to be damaged by the penetrated moisture owing to the delamination between the fiber and the matrix after water immersion. For the three and four layers specimens, their contradictory tensile strength suggests that the thicker specimen can delay the moisture permeation and is of better water durability.
Effect of Molar Ratio of Al2O3 to Fe2O3 on the Sintering and Thermal Shock Resistance of Al2O3-Fe2O3 Composite
Authors: Wang Zhi Fa , Wang Jian Sheng , Chen Yue Jun , Yu Li Xue , Bu Jing Long , Wang Rong Lin
Published: February 2011

The Al2O3-Fe2O3 composite was prepared at 1550°C for 3h with alumina powder and ferric oxide powder as raw materials and with magnesia powder as additive. The effect of molar ratio of Al2O3 to Fe2O3 on the sintering and thermal shock resistance of the composite materials was studied. The results showed that the apparent porosity and bulk density of the samples both decreased with the molar ratio of Al2O3 to Fe2O3 increase, as a result, the linear change ratio and bending strength both increased. When the molar ratio of Al2O3 to Fe2O3 equals to 3, the sample exhibits excellent thermal shock resistance. The XRD and SEM analysis results indicated that the mechanical and thermal proprieties are relative to the microstructure and crystal phases of the composite materials.
Effect of Sintering Temperatures on the Sintering Performance and Thermal Shock Resistance of MgO-Al2O3-Fe2O3 Composite
Authors: Bu Jing Long , Cai Yan Qing , Yu Li Xue , Wang Zhi Fa , Wang Rong Lin
Published: February 2011

The composites in the MgO-Al2O3-Fe2O3 system were prepared using high pure magnesia and alumina as raw materials and ferric oxide powder as additive. The effect of sintering temperatures on the sintering performance and thermal shock resistance of the composites was studied. The results showed that both the apparent porosity and linear change ratio of the samples decreased with the increase of sintering temperatures, and their bulk density and bending strength increased accordingly. The sample sintered at 1550°C exhibits excellent thermal shock resistance. The XRD and SEM results indicated that the crystal phase of the samples remained the same, but their microstructure became denser as the sintering temperatures increased from 1500°C to 1600°C. As a result, the composites could be sintered at about 1550°C, which has a potential application in cement rotary kiln linings.
Research on Oxidation Reaction of AlN Powder
Authors: Wang Rong Lin , Bu Jing Long , Yu Li Xue , Wang Zhi Fa , Sun Jia Lin
Published: February 2011

The process of non-isothermal oxidation of AlN powder (d50=15μm, 5μm and 0.5μm) were studied by TG-DTA and XRD in atmosphere of 80%N2 and 20%O2 mixture at flowrate of 55ml/min and heating rate of 10 /min. The experimental results reveal that the AlN powder obviously began to be oxidated and its weight increased at 900-1000°С . The process of dynamics of oxidation reaction between AlN and O2 was controlled alternately by reaction and diffusion. Non-isothermal oxidation dynamic parameters (activation energy E, reaction orders n and pre-exponential factor A) of d50=5μm AlN powder were obtained by the experimental data. E equals about 417.4kJ/mol, n about 2.9 and A about 3.47×1012. Due to smaller activation energy E and larger pre-exponential factor A in dynamic parameters of AlN powder non-isothermal oxidation, powdery AlN is easily oxidated at high temperature and in air and has a larger oxidation reaction rate. If AlN material with high thermal conductivity characteristics is introduced to prepare composite with high thermal shock resistance, the AlN powder must be treated for oxidation resistance.
Dynamic Effective Properties of Particle-Reinforced Composites with Imperfect Interface
Authors: Liu Xi Qiang , Wei Pei Jun , Wang Li , Zhang Gui
Published: February 2011

Elastic wave scattering of single spherical particle and the multiple scattering in particle-reinforced composite with imperfect interfaces are studied by the use of wave function expansion method. Four typical interfaces are obtained by appropriate selection of spring constants in the classical spring interface model, i.e. perfect interface, slide interface, rough interface and unbonded interface. The jump and continuous conditions of displacement vector and traction vector are used to derive the equation which the unknown expansion coefficients of the scattered wave field satisfy. Furthermore, the multiple scattering in composite reinforced by random distributed spherical particles is investigated. The effective velocity and attenuation of coherent waves and the dynamic effective moduli of composites are evaluated. The numerical simulation is performed for the SiC-Al composite. The influences of interface parameters on the scattering cross section, the effective velocity, the effective attenuation and the effective elastic moduli are discussed.
Microstructure and Mechanical Properties of In Situ WC Particles Reinforced Iron-Based Composite Coating
Authors: Fu Yong Hong , Niu Li Bin
Published: February 2011

A kind of centrifugal casting plus in situ techniques of fabricating iron-based composite coating reinforced by tungsten carbide (WC) particles was developed. The experimental results show that the reinforcing particles were generated by reaction between dissolved tungten wires and carbon from gray cast iron molten. The composite coating mainly consists of primary WC carbides, some fine secondly WC carbides as the reinforcing phase and pearlite accompanied by negligible graphite flakes as the matrix. Compared with the unreinforced gray cast iron, the in situ synthesized WC particles can enhance the ultimate tensile strength and decrease elongation rate of the composite coating. Fracture morphology reveals that fracture mode of composite coating is brittle and ductile mixed fractures, the fracture mechanism of the composite is not only related with the introduction of reinforcement but also with the reduction of graphite flakes in the matrix
Preparation and Characterisation of TiO2-Supported on the Surface of SiO2
Authors: Bu Shan , Gao Zi Wei , Li Jin Ling , Tikkanen Wayne
Published: February 2011

A surface TiO2-supported of silica composite material was prepared by surface organometallic chemistry method and the structure was characterized by FTIR, EDAX and XRD. The results show the bonding interaction between TiO2 and SiO2, linking by Si-O-Ti bond. Furthermore, the anatase phase crystal structure is observed by XRD analysis.
A Study of Ramie Fiber Reinforced Polypropylene Composites
Authors: Sun Yi Ming , Peng Dan , Li Man
Published: February 2011

Ramie fibers were incorporated into polypropylene as the reinforcement fillers. The transesterification between the hydroxyl groups of ramie fiber and the ester of maleic anhydride was employed to improve the compatibility of ramie fibers and the polypropylene matrix. The morphology of the composite surfaces and interfaces were studied using IR and SEM. The mechanical properties and water absorption of the composites were investigated. The results demonstrated that the esterification occurred on the surface of ramie fiber, due to which the compatibility between fiber and matrix treated was greatly improved. Because of the improved compatibility, the mechanical strength of the composites increased; while water absorption decreased.
Characteristic of Raman Spectra, Crystal Structure and Superconductivity of Fe-Doped GdBa2Cu3-xFexO7-δ Systems
Authors: Li Tao , Xue Ren Zhong , Wang Chun Mei , Su Lei , Dai Hai Yang , Chen Zhen Ping
Published: February 2011

The effects of Fe doping on the structure, electronic transport properties and Raman spectra of GdBa2Cu3-xFexO7-δ (x = 0.00-0.30) systems have been investigated. The analysis of X-ray diffraction patterns shows that the compound undergoes an Orthorhombic–Tetragonal (O-T) phase transition in the doping range of x = 0.05-0.10. The superconducting transition temperature Tc decreases with the increase of Fe doping level, whereas the superconducting transition width increases abruptly with O-T transition. We have discussed the Raman shifts and intensity of the five normal phonon peaks and some other peaks which result from the vibration of Cu(1) and O(1) oxygen for the Fe doped-samples. These investigations reveal that the electronic transport properties and Raman spectra of GdBa2Cu3-xFexO7-δ composites obviously depend on O-T transition induced by the Fe doping.
Design of the Stitching Parameters Applied to the Laminates with Cut-Out
Authors: Wang Yi , Yue Zhu Feng , Li Lei
Published: February 2011

A novel stitching reinforcement method is applied to the laminates with cut-out for a decrease in the interlaminar stresses . The stitching parameters, such as the distance between edge and stitch line, the thread radius, and the stitch step etc.,are designed,and the three-dimentional models are established for FEM (Finite Element Method). The maximum circumferential shear stress appears in laminates of 0/-45, showing stress distribution similar to analytic solutions . The interlaminar circumferential shear stress of stitched is significantly decreased, and the validity of this method is proved.
Parametric Study of Hysteretic Behaviour of Combined Welded Heavy Steel Plates with Accumulative Damage
Authors: Yang Na , Zhang Jing Jing , Guo Ting
Published: February 2011

The accumulative damage model in which the material’s plastic strain is defined as variable and the energy dissipation is also considered is applied to the combined welded heavy steel plates. And the reliability of the model is confirmed by comparing the computed results in finite element project ABAQUS to tested results from previous researcher. On that basis, a series of steel plate components are computed to analyze their hysteretic curves and ductility factors. The influences of steel plate thickness, web’s height-thickness ratio and flange’s width-thickness ratio on hysteretic behavior are studied.
Shear Strength Upgrade of Perforated RC Shearwalls Using Prestress and Steel Plate
Authors: Choi Chang Sik , Bae Baek Il , Choi Hyun Ki , Park Il Sung
Published: February 2011

Remodeling is also an environmentally-friendly approach that reduces the amount of waste in construction site. Specifically, there are many attempts to make house more wide according to the merging of two old houses in apartment buildings. For making two houses into single housing area, openings shoud be needed or walls should be removed. However, removing shearwalls are very dangerous attempt because of reducing of lateral load capacity of buildings. Therefore many engineers prefer to leave shearwalls. However, there are insufficient studies about partial damage, that is, openings. In these cases the damaged shear walls need to be retrofitted by additional materials or members. In this research, four specimens were tested to investigate the capacity of the damaged wall and the retrofitted wall. The artificially damaged wall was prestressed by tendons to improve the shear capacity of the wall, and the other walls were retrofitted by adding steel plate at the surface for the same purpose. Consequently, these retrofitted walls had improved capacity and stiffness in both shear and flexure. Especially, the wall with steel plate showed ductile behavior after ultimate load and the prestressed wall had greater stiffness than the unstrengthened prototype wall.
Study on Properties of Foam Concrete Based on Fractal Theory
Authors: Tian Wen Ling , Yang Jiang Bo , Zhao Xiao Yan
Published: February 2011

Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.
Dynamic Analysis of Steel Tube and Concrete-Filled Steel Tube High-Limit Protection Racks under Impact Loads
Authors: Ju Ao Tian , Qu Shu Ying , Hou Xing Min , Wang Jin Tian
Published: February 2011

The purpose of high-limit protection rack under railway bridge is to protect railway bridge, and avoid passing vehicles under railway bridge colliding bridge. The paper discusses dynamic response and energy transfer of two different structures by analyzing the internal force, deformation, displacement and energy transfer of the steel tube and concrete-filled steel tube protection racks in collision. The result shows that the displacement of concrete-filled steel tube protection rack is smaller, and it can bear larger impact force and have good effect of energy absorption.
Research on a New Type of Rolling Ball Isolator
Authors: Sui Jie Ying , Gong Yan Wen , Liu Wen Feng
Published: February 2011

In this paper, a new type of rolling ball isolator was developed. The rolling ball isolator isolates horizontal earthquake with SMA dampers to restore to normal position, and dissipate energy. The optimization of SMA-Rolling ball isolator is studied. Adopt MATLAB to build the shear model, and contrasts the earthquake response between the isolated structure and the un-isolated structure.
Study on Heavy Section Forging Steel for Reactor Pressure Vessel Applying Simulation Methods
Authors: Xu Xue Xia , Bai Bing Zhe , You Wei
Published: February 2011

The composition and heat treatment of heavy section forging steel for reactor pressure vessel were optimized applying physical and numerical simulation methods, including numerical simulation to calculate temperature distribution during quench of model forging, artificial neural network to predict CCT diagrams of steels and small sample control cooling to simulate specific heat treatment. And the influence of compositon and heat treatment on microstructure and properties were discussed. Results showed that the experimental steel obtained satisfactory properties based on optimization of chemical composition and heat treatment. It is estimated that the hardenability and temper stability of experimental steel were improved by tungsten alloyment and higher temperature temper was good for superior microstructure, proper strength and better toughness. In the present work, application of simulation methods is proved to be reasonable for study on heavy section forging steel.
Seismic Isolation Effect of a Tunnel Covered with Expanded Polystrene Geofoam
Authors: Wang De Ling
Published: February 2011

In this study, Expanded Polystrene (EPS) geofoam is used as seismic buffer to mitigate shock damage of tunnel by earthquake. Four types of EPS layer with different elastic modulus are selected to investigate their isolation effect. Four kinds of thickness are also selected to study the effect of thickness. All tunnels with different EPS layers are compared with each other and with the tunnel without EPS layer. Detailed simulation technology is described in this paper, including the infinite element boundary, initial ground stress balance and material models. The numerical analysis show that the axial strain and section force of lining are greatly reduced compared with the tunnel without EPS. With the decreasing elastic modulus and increasing EPS layer thickness, the mitigation effect is more obvious. And the isolation effect of reducing modulus is greater than that of increasing thickness. So modulus of EPS layer is a more important factor for mitigating dynamic damage.
Analysis for Seismic Response of Long Span Rigid Frame Bridge
Authors: Ning Xiao Jun , Zhou Yi Tang
Published: February 2011

Rigid frame bridge is widely used in China because of its lower cost. The aseismatic ability of rigid frame bridge is difficult to judge for designer when the bridge is used to span valley in intensity region. The seismic response of one rigid frame bridge with 160m span is calculated. It is indicated that the aseismatic ability of rigid frame bridge is good and bridge design is controlled by bending moment at bottom of pier.
Finite Element Analysis of Air Cooler Used in Nuclear Power Station
Authors: Hu Shao Qing , Zhang Yong Li
Published: February 2011

According to the characteristics of cooler, the finite element model of air cooler is established using ANSYS f software. The force and moment are acted on nozzles using MPC184 element. The first natural frequency is given. Then the stresses of cooler under normal operating load case and under accidental load case are calculated respectively. The stresses of nozzles and foot were checked according to RCC-M specification and meet the requirements.
Seismic Behaviour on Composite Strengthening for Existing Reinforced Concrete Short Columns
Authors: Zhao Gen Tian
Published: February 2011

In order to develop an effective seismic shear strengthening method for improving the earthquake behavior of existing R/C short columns, experimental studies are conducted by using four beam-column sub assemblage specimens with a short column. Three short columns of these specimens are strengthening by steel plates and concrete, while other one is without any steel plate strengthening. All the specimens are tested under a constant gravity load and alternately repeated lateral forces. Test results demonstrate that, if the short column is strengthened by a welded square tube and concrete, then brittle shear failure does not occur and the column can develop its ultimate flexural moment capacity. It is also shown by tests that the proposed strengthening method using steel plates and concrete is applicable to repair and rehabilitate the damaged short columns failed in the brittle shear mode.
Research on Semi-Active Control of Large-Scale Aqueduct
Authors: Huang Liang , Wang Bo , Xu Jian Guo
Published: February 2011

The magneto rheological damper (MRD) is employed to control the seismic response of large-scale aqueduct. The active control, semi-active control and passive control strategies are systematically compared, The results indicated that the magneto rheological dampers are effective in reducing the aqueduct response, the mitigation rate of semi-active control approaches with the active method The results from the present study may serve as a reference base for seismic design of large-scale aqueducts, and provide theoretical basis of aqueduct using semi-active devices.
The Analysis of Temperature Field and Residual Stress Distribution during H-Beam Cooling Process
Authors: Zang Yong , Zhang Bo , Cui Li Hong , Gao Zhi Ying
Published: February 2011

A spot-test of cooling after the finish-rolling was performed for the typical H-beam and the temperature field during the process and residual stress in the beams after the cooling were measured. By using finite element method, the cooling temperature-field of the H700×300 H-beam was simulated and the thermal stress distribution formed in this process was calculated by using thermo-mechanical coupling function. The simulation results matched well with the data obtained on the spot. The accurate description performed in this paper for the temperature field and residual stress distribution of H-beam during cooling process is especially helpful to the manufacture plant. According to the results the reasonable technical parameters can be constituted to control the temperature of the beam in the cooling process and reduce the residual stress in the final product.
Comparative Study on the Pseudo-Dynamic Testing of Semi-Rigid Connection of Steel Frames with or without Brace
Authors: Lv Jia , Zhang Qi Lin
Published: February 2011

The horizontal stiffness of steel frame is relatively weak. So designers introduce brace system into steel frame to increase the horizontal stiffness. In order to guarantee the safety of the structure, we should imitate the performance of the structure under seismic loads. In this paper, the pseudo-dynamic test was conducted on the semi-rigid connection of steel frame and the semi-rigid connection of steel-braced frame. The test results show that the brace can increase the ductility of the structure, decrease the displacement of the top floor, decrease the interlayer displacement, and bear ground floor shearing-force. So the brace greatly impacts the performance of the structure. It has the ability of anti-earthquake and strong resistance ability of lateral force.
A New Seismic-Isolation Device Applied in Continuous Beam Bridge
Authors: Yan Bin
Published: February 2011

Continuous beam bridge was widely used, while seismic problem of it was prominent in meizoseismal area. According to seismic-isolation principle and mechanism of PSD, seismic performance of PSD were studied and the parameters of PSD were analyzed later, based on south approach of North Branch of Xia-Zhang Sea-Crossing Bridge. It was found that PSD, a combination of preloaded spring and liquid viscous damper, was an effective seismic-isolation device which could significantly reduce the seismic response of continuous beam bridge in longitudinal and transverse direction. Damper coefficient was the main parameter of PSD, while preloaded force, linear spring stiffness and damper index had a little effect on seismic performance of PSD.
Effects of Compound Silicate Gangue on Mineral Composition and Microstructure of Sinter Produced by Baiyunebo Iron Ore Concentrates
Authors: Luo Guo Ping , Wu Sheng Li , Wang Yi Ci , Zhang Guang Jie , Hao Zhi Zhong , Wu Hu Lin
Published: February 2011

The effects of compound silicate gangue on mineral composition and microstructure of sinter produced by Baiyunebo iron ore concentrates was studied by using mini-sintering test device and optical microscope. The result showed that compound silicate gangue has lower melting point, wider melting temperature range, longer melting time and melts easily to form glassiness during the sintering process. It can promote the solution of CaO and CaF2 in glassy phase, which affects viscosity and fluidity of glassy phase as well as the homogeneity of sinter microstructure. The compound silicate gangue intensely inhibits the generation of complex calcium ferrite and cuspidine as well. The major mineral compositions of sinter are hematite and glassy phase. The sinter exhibits multi-cavities and grainy structure when SiO2 exists entirely in the form of compound silicate gangue.
Dynamic Responses of RC Underground Subway Station and Soil during the Strong Earthquake
Authors: Bian Jin , Tao Lian Jin , Wang Wen Pei , Zhang Bo
Published: February 2011

Underground subway RC structures suffered significant damage during many earthquakes, so it is important to study the seismic behavior on RC subway structure. The shaking table model test is made of the Beijing typical subway station structure. In this article, the test is introduced briefly; then, the acceleration history curves are analyzed. By the test, it is found that the interaction exits between structure and soil. Under the low intensity earthquake, the underground structure will exert a very small influence on soil and vibrates with soil; under the high intensity earthquake, the soil will exert a large thrust on the underground structure and the relative displacement exists between them. Moreover, At the bottom of the structure side wall, the peak acceleration is larger than it in soil around the place, and at the top and middle of the structure side wall, the peak accelerations are smaller than them in soil around the place; with the depth increase, decrease the peak value, the excellence frequency and its amplitude of the acceleration time history.
Dynamic Fracture Toughness Test and Evaluation for S135 Drill Pipe
Authors: Sun Yong Xing , Lin Yuan Hua , He Long , Shi Tai he , Zhu Da Jiang , Chen Li Ping , Liu Su Jun
Published: February 2011

During oil-drilling, the fractures of drill tool thread and piercement of drill pipe upset transition are very common in drill pipe failure as an object of petroleum and metallurgical researchers home and abroad. The classical fracture mechanics can only resolve the static fracture problem of oil country tubular goods (OCTG), but not resolve drill pipe failure under dynamic load. It is well known that the API 5D just prescribes strength criterion of drill pipe material but fracture toughness of drill pipe material. So, it is important to study dynamic fracture toughness of drill pipe material and present appropriate toughness criterion, which can not only optimize the drill string structural design, but also reduce fracture failure of drill string. On the basis of presenting main test means of dynamic fracture toughness and referring to the Charpy V test, the new impact experiment instrument is developed. Numerical and experimental comparisons show that the repeated dynamic fracture toughness tested by the impact experiment instrument is more accurate than one time impact, which can better show material characteristic and provide a reliable way to distinguish material characteristic, in the meantime, the correlations between dynamic fracture toughness of drill pipe material and failure of drill pipe is obtained.
Studies on Technological Parameters of Optimal Soft Reduction about Superwide Slab Caster
Authors: Qi Xin Xia , Zhang Geng , Jia Qi
Published: February 2011

Based on practical production technology, using some methods like segregation index analysis, the research is focused on the relationship between the maximum segregation index of carbon, phosphorus, sulfur in superwide slab and rolling reduction, reduction ratio, reduction rate of superwide slab caster. During the process of soft reduction, the theory that the minimum of the maximum segregation index corresponds to the technological parameters like optimal rolling reduction, optimal reduction ratio, optimal reduction rate of the superwide slab caster can be provided as a theoretical basis for the production of superwide slab.