bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of Lead-Free and High Tc Positive Temperature Coefficient of Resistivity Ceramics Sintered in Air
Authors: Zhao Jun , Yang Hai Bo , Gong Shu Ping , Zhou Dong Xiang
Published: December 2011

As a lead-free positive temperature coefficient of resistivity (PTCR) material, [Ba0.95-x (K0.5Bi0.5)0.05Cax]1-yNbyO3 system was prepared by the conventional solid-state reaction method. All samples sintered in air at 1300°C possess PTC characteristics as well as semi-conductivity characteristics, especially they show high Tc(130°C~160°C) value and the jump of the resistivity (maximum resistivity ρmax / minimum resistivity ρmin ) is four orders of magnitude. Samples with the composition of 0.3mol% Nb5+ have low room-temperature resistivity (ρ25°C) of ~103Ω.cm.
Synthesis, Thermal Expansion Properties and Raman Spectroscopic Study of Ca1-xSrxZr4P6O24 Ceramics
Authors: Wang Zhi Hong , Xie Dong Yan , Yuan Bao He , Liu Xian Sheng , Song Wen Bo , Yuan Bin , Liang Er Jun
Published: December 2011

A simplified method with much lower time and energy costs is presented for the rapid synthesis of low thermal expansion materials of CaZr4P6O24, SrZr4P6O24 and their solid solution Ca0.5Sr0.5Zr4P6O24. The coefficients of thermal expansion of CaZr4P6O24, SrZr4P6O24 and Ca0.5Sr0.5Zr4P6O24 are measured to be -1.45×10-6, 2.1×10-6 and 0.26×10-6, respectively. Raman spectroscopic study confirms the formation of the solid solution of Ca0.5Sr0.5Zr4P6O24 though its symmetric and asymmetric stretching modes are obviously broadened with respect to those of CaZr4P6O24 and SrZr4P6O24 due to the lattice deformation by incorporation of Ca2+ and Sr2+ with different cation size. The shifts of the asymmetric stretching Raman modes and the librational/translational modes with temperature in Ca0.5Sr0.5Zr4P6O24 are between those in CaZr4P6O24 and SrZr4P6O24, suggesting a cancelling effect of Ca2+ and Sr2+ cations in the thermal expansion of Ca0.5Sr0.5Zr4P6O24.
The Influence of Ba-Ti Ratio on the Electrical Properties and Microstructures of the BaM-0.007Sm0.007TiO3 Based Ceramics Fired in Reducing Atmosphere
Authors: Cheng Xu Xin , Zhou Dong Xiang , Fu Qiu Yun , Gong Shu Ping
Published: December 2011

Electrical properties, positive temperature coefficient of resistivity (PTCR), and microstructures of (Bam-0.007Sm0.007)TiO3(BST) with different Ba-site/Ti-site (A/B) ratio sintered in a reducing atmosphere and reoxidized in air are investigated. The results reveal that the room temperature resistivity of the semiconducting BST ceramics first decreases and then increases with increasing of A/B ratio (m), particularly when m is equal to 1.006, the semiconducting BST ceramics which have been sintered in a reducing atmosphere and reoxidized at 800°C exhibit significant PTCR effect with a resistance jumping ratio of 3 orders magnitude, and achieve a lower room temperature resisitivity of 80.8 Ω∙cm, in addition, the grain size distribution of the Ti-excess specimens is much better than that of the Ba-excess ones.
Effect of Bi2O3 Addition on the Physical and Electrical Properties of Lead-Free (Na0.5Bi0.5)TiO3-Ba(Sn0.08Ti0.92)O3 Ceramics
Authors: Wang Chun Huy
Published: December 2011

In the present study, various quantities of Bi2O3were added into 0.98(Na0.5Bi0.5)TiO3-0.02Ba(Sn0.08Ti0.92)O3(0.98NBT-0.02BST) ceramics. High-density samples were obtained through the addition of Bi2O3into 0.98NBT-0.02BST ceramic. It was found that 0.98NBT-0.02BST with the addition of 0~3.0 wt.% Bi2O3exhibit relatively good piezoelectric properties. For 0.98NBT-0.02BST ceramic with the addition of 2 wt.% Bi2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.12 and 0.61, respectively, at the sintering of 1100oC for 3 h. The ratio of thickness coupling coefficient to planar coupling coefficient is 5.1. It is obvious that 0.98NBT-0.02BST solid solution ceramic by adding low quantities of Bi2O3is one of the promising lead-free ceramics for high frequency electromechanical transducer applications.
The Evaluation of Wheelchair Comfort Based on Analytic Hierarchy Process
Authors: Guan Tian Min , Qin Mei Chao , Yuan Yan Li
Published: December 2011

Abstract. The wheelchair comfort is a subjective evaluation of users, which is influenced by wheelchair itself, environmental factors and physiological factors. It is difficult to make evaluation about wheelchair comfort by a general approach. In this essay, Analytic Hierarchy Process, based on a scientific decision-making idea which combines qualitative analysis with quantitative analysis, was used to establish the evaluation system about wheelchair comfort indicator, and the weight of each indicator was determined. For this reason, the evaluation of wheelchair comfort is more scientific and reasonable.
Influence of CeO2 Nanopowder on Crystallization Behavior and Sintering Performance of Fused Quartz Ceramic Materials
Authors: Yu Li Xue , Chen Yue Jun , Bu Jing Long , Chen Jun Xing , Wang Zhi Fa
Published: December 2011

Fused quartz granule was used as raw material, and CeO2 nanopowder was used as additive with dosages of 1wt %, 2 wt % and 3 wt %. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h, respectively. The properties of samples including apparent porosity, bending strength and thermal expansion ratio were measured. The results show that the sample with 1 wt % CeO2 nanopowder has the lowest apparent porosity, the highest bending strength and the lowest thermal expansion ratio. The XRD and SEM results show that through the CeO2 nanopowder adding, the diffraction peak intensity of quartz phase in the fused quartz ceramics decrease, and the microstructure of the samples become more compact. It can be deduced that CeO2 nanopowder plays the excellent role as the crystallization inhibitor and sintering assistant to fused quartz materials sintered at various temperatures.
Study on Microstructure of ZnO Lighting Arrester with High Voltage Gradient
Authors: He Mo , Liu Qi Bin , Xia Chang Qi
Published: December 2011

To obtain ZnO arrester with high voltage gradient and small size, through the optimizing foundamental formula of arrester and changing sintering temperature and holding time, the electrical properties and microstructure of varistors were studied. The density of varistors was determined by using the mass - volume method , voltage gradient and leakage current of ZnO arrester were measured with Ⅱ Surge Arrester Tester DC parameters, microstructure of varistor ceramics were studied by means XRD and SEM. The experimental results show that with increasement of the sintering temperature, the density of varistors increases, and the voltage gradient continues to decrease and leakage current almost keeps unchangable. As the holding time increases, while as the voltage gradient continues to decrease, and leakage current almost unchanges.
Fracture Behavior and Microstructure of 60Si2MnA Spring Steels Modified by V-Nb Inoculants
Authors: Wang Tie Bao , Cui Chun Xiang , Fang Lin , Bu Shao Jing
Published: December 2011

The microstructure of V-Nb inoculants after melt spinning was investigated by performing TEM examination and to the sample steels, the prior austenite grain sizes and fracture morphology were investigated by SEM observation. The results show that the V-Nb inoculants obtained is amorphous and the sample steel modified by V-Nb inoculants which make it possible to be a large amount of nucleation centers existing in the form of (V, Nb)C and achieve the effect of grain refinement in the solidification stages of liquid steel has been found to have the finest prior austenite grain sizes and the average prior austenite grain sizes of steel without addition of V and Nb(Steel A), steel microalloyed with V and Nb(Steel B) and steel modified by V-Nb inoculants(Steel C) are respectively 30μm, 20μm and 10μm. Tensile behavior of samples was studied under tempering at 400°C for 30 min after quenching, tensile results show that the fracture of steel modified by V-Nb inoculants appears dimples which represent ductile fracture. However the tensile fracture of V-Nb microalloyed steel is mixture of quasi-cleavages and dimples. Under tempering at 550°C for 30 min, Steel B and Steel C both show a fractograph with cleavage fracture.
Effect of Solid Solution on the Microstructure and Performance of Nuclear Power Slot Wedge Copper Alloy
Authors: Xu Yu Song , Lin Na Na , Jiao Ya Li
Published: December 2011

According to the working conditions of the nuclear power generator slot wedge and the principle of the heat treatment, CuCo2BeZr copper alloy was strengthened by a series of heating process test, finally acquired a good performance of the nuclear power slot wedge. The results show that, after the process of hot extrusion deformation of 85.5% and solution treatment at (940±10 )°C for 2h, then aging at 540 °C for 4h, the composition, microstructure, fracture morphology and tensile properties of CuCo2BeZr copper alloy, as the material of nuclear power generator, could meet the conditions of working continuously in high temperature enviroment.The research of CuCo2BeZr copper alloy provide scientific basis for analyzing the inner mechanism of the failure and predicting the working life of the nuclear power slot wedge material.
Electromechanical Analysis of a Beam Piezoelectric Transducer Energy Harvest Device
Authors: Xu Meng Hua , Wang Bao Lin
Published: December 2011

This paper considers the vibtation problem of beam piezoelectric transducer. Traditional reasearches face difficulties in providing the analytical expression for the piezoelectric effect of the piezoelectric vibrator with a mass at its end as well as the improper model of piezoelectric vibrators which work in high-frequency band. In this paper, the nature of the current output in a large frequency range is explored. Firstly, static analysis of cantilever is conducted and the piezoelectric effect under a certain deformation were formuled. Next, the main vibration modes of the cantilever were modified so that the main modes are of orthogonality in nature and satisfy the boundary conditions. The dynamic deflection of the piezoelectric cantilever was also investigated using the modified vibration modes. Charge outputs of piezoelectric cantilever beam are also demonstrated. Finally, based on the theoretical analysis, some numerical results are given.
Titanium Boride in High Nb Containing TiAl Alloy: Morphology and Effect on Mechanical Properties
Authors: Xu Xiang Jun , Lin Jun Pin , Wang Yan Li
Published: December 2011

The morphology of titanium boride in as-cast and as-forged Ti-45Al-8.5Nb-(W, B, Y) alloy containing 0.2at. % boron and the effect of borides on tensile and creep properties of the alloy are investigated. The results show that in as-cast alloy the morphology of boride appears mainly convoluted ribbons with some flakes and particles. With the extent of forging increases, the length of the ribbons decreases and their distribution is more uniform. The long ribbon in as-cast alloy is detrimental to tensile properties at both room temperature (RT) and high temperatures. The short ribbon in as-forged alloy is not harmful to RT tensile properties, but is harmful to tensile and creep properties at high temperatures. The harmful effect of the boride is due to the strain incompatibility of boride and matrix, which causes many cavities at boride/matrix boundaries and results in ultimate fracture.
Application of Benzyl Ester of Modified Vegetable Oils as Rubber Processing Oils
Authors: Boontawee Hasleena , Nakason Charoen , Kaesaman Azizon , Thitithammawong Anoma , Chewchanwuttiwong Sopa
Published: December 2011

Benzyl esters of fatty acids based on three types of vegetable oils (i.e., coconut, palm, and soybean oils) were in-house prepared. They were used as alternative rubber processing oil to replace conventional aromatic oil which has been banned by European community since December 2009. Fatty acids were first prepared by hydrolysis of vegetable oils and thereafter esterified with benzyl alcohol in the presence of sulfuric acid as a catalyst. The reaction based on molar ratio of fatty acid:benzyl alcohol:sulfuric acid was set at 1.5:1.0:0.05 gave yield of benzyl esters higher than 80%. Rubber compounds containing different types of benzyl ester were prepared according to the standard formulation of ASTM 3184. It was found that the processing oil in the form of benzyl esters is possible to use instead of aromatic oil in rubber formulation. Various parameters and properties include mixing energy, Mooney viscosity, curing, mechanical and dynamic mechanical properties of rubber compounds and vulcanizates have been investigated.
In Vitro Bioactivity of a Biocomposite Fabricated from Ti and Mg Powders by Powder Metallurgy Method
Authors: Sharifi Sede Ehsan , Mirdamadi Shamsedin , Arabi Hossein
Published: December 2011

This study sought to create a biocomposite of Magnesium and Titanium via a powder metallurgy technique. Powder metallurgy technique was used to produce three different volume percentages of Magnesium (30% , 35% , 40%). Titanium powder was mixed with Magnesium, then the samples were compressed by 1800 Bar using a cold, isostatic press process. The samples were then sintered to 850 for 100 min. At this temperature, the compressive yield strength was increased to 210 Mpa and significantly depended on the volume percent of Magnesium present, the core size and temperature of sintering. The bioactivity of the samples in a simulated body fluid (SBF) was also investigated. When the samples were immersed in the simulated body fluid for a 14 and 28 days, calcium and other elements were found to be deposited on the surface. Additionally, it was found that TiO2 has the ability to induce the formation of bone-like apatite in the SBF. In addition, the degradation product of Magnesium in a biological system caused a rise in the pH and environment for the deposition of calcium and other element on the surface were enhanced. Finally, the samples were analyzed using XRD, EDS, and optical and scanning electron microscopy (SEM).
Effect of Different Aging Temperatures on Interfacial Reaction between SAC305 and ENEPIG Surface Finish
Authors: Azlina Osman Saliza , Ourdjini Ali , Idris Siti Rabiatull Aisha , Azmah Hanim Mohd Ariff
Published: December 2011

In electronic packaging industry, they are now driven technology to green product by replacing leaded-solder with lead-free solder in order to fulfill the European Restriction of Hazardous Substance (RoHS) compliance. Thus, Sn-Ag-Cu lead-free solder family is one of candidates can fulfill this requirement. This study investigates the interfacial reactions during reflow soldering and isothermal aging between Sn-3.0Ag-0.5Cu (SAC305) and electroless nickel/ immersion palladium/immersion gold (ENEPIG). Reliability of solder joint is also examined by performing solid state isothermal aging at 125°C and 150°C for up to 2000 hours. The results revealed that after reflow soldering, (Cu, Ni)6Sn5 IMC is formed between solder and substrate while after aging treatment another IMC was found between (Cu, Ni)6Sn5 and substrate known as (Ni, Cu)3Sn4. Aging time and temperature of solder joints results in an increase of IMC’s thickness and changes their morphologies to become more spherical, dense and with larger grain size. In addition, the results also revealed that the thickness of intermetallics formed is proportional to the aging duration and temperature.
The Research on the Interfacial Adhesion of Polypropylene-Magesium Hydroxide Composite Modified by Different Compatibilizers
Authors: Shen Hao , Mai Kan Cheng , Liang Dong
Published: December 2011

In order to investigate the effect of interfacial adhesion on phase morphology, crystallization behavior and tensile property of magnesium hydroxide filled polypropylene (PP/MH) composites, PP blends with compatibilizers, compatibilised and uncompatibilised PP/MH composites were prepared in this work. Three different types of compatibilizers namely, polypropylene grafted-maleic anhydride (PP-g-MA), ethylene-octene copolymer grafted with maleic anhydride (POE-g-MA) and ethylene-vinyl acetate copolymer grafted with maleic anhydride (EVA-g-MA) were used to control the interfacial adhesion among the components. SEM analysis revealed the formation of an encapsulation structure in PP/compatibilizer/MH composites. The interfacial tension (γAB) and wetting coefficient (ωα) results also confirmed the formation of encapsulation structure in these ternary composites. Addition of compatibilizers improved the interfacial adhesion between PP matrix and MH particles and resulted in improvement in tensile strength.
Quantitatively Ca3SiO5 Particles Adherence Affected the Teeth Enamel Remineralization
Authors: Dong Zhi Hong
Published: December 2011

Tricalcium silicate (Ca3SiO5) bioceramics have good bioactivity and compatibility. In simulated oral fluid they can induce teeth mineralization to repair the acid etched dental enamel. But teeth mineralization effect was relied on particles adhesive ability onto the enamel surface, so a new and simple method was established to evaluate the adherence quantitatively by optical micrograph analyzer and particle counter based on light blocking theory, and further verified Ca3SiO5 particle size affected mineralization effect in stimulated oral fluid (SOF) by nanoindentaion depth. The results indicated that particle size affected the adhesive capability and mineralization ability, in the size of 1-10μm is optimal selection as a toothpaste agent against early caries.
Preparation of MIP Microspheres by Precipitation Polymerization with 1-Phenyl-1-Propanol as Template
Authors: Yao Chuan Yi , Li Qing Qing , Lu Ying Hua
Published: December 2011

Molecular imprinting polymer microspheres were prepared by precipitation polymerization with methacrylic acid as functional monomer and 1-phenyl-1-propanol as template. The effects of synthesis conditions, including the kind of solvent, polymerization temperature, the concentration of template and initiator, rotational speed and pre-polymerization time, on the characteristics of the molecularly imprinted polymer microspheres were studied. The rebinding experiments showed that the molecularly imprinted polymer microspheres synthesized by precipitation polymerization at 60°C, with acetonitrile as solvent and the concentrations of both template and initiator of 0.01mol L-1, have good specific recognition and higher affinity capacity.
Influence of outside Environmental Variations on Adsorption Characteristics of Waste Dusty Slag /EPDM Composite
Authors: Liu Xiu Qi , Xing He Qin
Published: December 2011

In our study, a new kind of material for toluene adsorption was prepared by melt blending with EPDM as the matrix and waste dusty slag as the filler. By considering the influence of pH, temperature, stirring speed on adsorption capacity. The results showed that the environmental pH has little effect on the toluene absorbency of the composite; “Room temperature” is the optimum temperature; increased the stirring speed can reduce the adsorption time.
Preparation of Salt-Resistance Superabsobent Microspheres by Inverse Suspension Polymerization
Authors: Zhou Ming , Zhao Jin Zhou , Yang Yan
Published: December 2011

Novel salt-resistance superabsobent microspheres based on acrylamide (AM), 2-acrylamido-2-methylpropane sulphonic acid (AMPS) by inverse suspension copolymerization using ammonium persulfate (APS) as the initiator and N,N-methylene bisacrylamide (MBA) as the crosslinking agent and surfactant PVA as disperse agent are prepared. The experimental results of salt-resistance superabsobent microspheres show the salt absorbency decreased with the increase of salt concentration; The maximum salt absorbency is 132g/g within 75min in 0.9% NaCl solution and the effect of calcium ion on salt absorbency is much greater than that of sodium ion. FTIR indicates the structure of the acrylamide and 2-acrylamido-2- methylpropane sulphonic acid copolymer. SEM indicates that the number of the micropores largely decreased with the water/oil ratio increasing from 4% to 10%. Elemental analysis indicate that the measured values of carbon, sulfur, nitrogen, hydrogen four elements is very close to theoretical value.
Fabrication and Thermoelectric Properties of Magneli Phases by Adding Ti into TiO2
Authors: Lu Yun , Matsuda Yusuke , Sagara Katsuhiro , Hao Liang , Otomitsu Takahito , Yoshida Hiroyuki
Published: December 2011

In the present study, the TiO2-Ti compacts with Magneli phases TinO2n-1were fabricated using the mixed powder of TiO2powder and addition Ti powder by spark plasma sintering (SPS). The composition and the crystal types of Magneli phases TinO2n-1were examined. The results showed that various Magneli phases TinO2n-1(single or multi Magneli phases) with the composition of Ti1+yO2-xwere obtained. The Magneli phases TinO2n-1were formed in the transformation from the mother phase rutile TiO2to TiO with increase in Ti addition fraction. In addition, the thermoelectric properties of the sintered compacts were also measured. The electrical resistivity of the sintered compacts decreased with increase in Ti addition fraction. The thermoelectric performance of the sintered compacts was improved by the formation of Magneli phases TinO2n-1with the composition of Ti1+yO2-x.
Theoretical Energy Distributions of Electrons from a Large Exponential-Doping GaAs Photocathode
Authors: Cai Zhi Peng , Yang Wen Zheng , Tang Wei Dong , Hou Xun
Published: December 2011

Theoretical calculation indicates that the large exponential-doping GaAs photocathodes have a much narrower electron energy distribution than traditional GaAs NEA cathodes, and the excellent performance attributes to the special structure characters of the band-bending region and lower negative electron affinity of the new-type GaAs photocathodes. The effects of surface doping concentration and work function on the energy distribution are discussed in details, and the FWHM of the energy distribution is less than 100meV. The simulation results indicate that the large exponential-doping mode further improves the features of the electron energy spreads for GaAs photocathodes, which may meet the further demand of next generation of electron guns.
A Study on Step-Like Magnetization Curves in Tb3Ga5O12 at Low Temperature
Authors: Chen Hui , Zhang Guo Ying , Yang Dan , Duan Yi Feng , Liu Hai Shun
Published: December 2011

The low temperature magnetizations of TbGG have been systematically investigated from the average effect of the nonequivalent crystal sites. Our calculated results show that the different nonequivalent crystal sites have the different contributions to the magnetization. The step-like appearance of the low temperature magnetization curves in TbGG originates from the average effect of the magnetizations of six nonequivalent crystal sites, not from the near-crossing of the lowest energy levels of Tb3+ions.
Effect of Annealing Temperature on the Properties of Silicon Crystal
Authors: Hao Qiu Yan , Xie Xin Jian , Wang Bing Zhang , Liu Cai Chi
Published: December 2011

In order to investigate the performance of silicon single crystal depended on the annealing temperature, the minority carrier lifetime, the resistivity and oxygen concentration after different temperature annealing in Ar ambient were examined. And the effect of oxygen and related defects formed during annealed on the minority carrier lifetime were analyzed by microwave photoconductivity method, Fourier transform infrared spectrometer and four-probe measurement. The results indicate that after 450°C annealing for 30h, the resistivity and minority carrier lifetime of silicon increase significantly, while the concentration of interstitial oxygen decreases. After the annealing at 650°C, oxygen donor can be removed and the resistivity and the minority carrier lifetime decrease. During the high-temperature (above 650°C) annealing, the oxygen precipitation can decrease the minority carrier lifetime silicon.
Characteristics of Two-Stage Γ-Gate on AlGaAs/InGaAs/AlGaAs DH-HEMTs by Using AlGaAs/InGaP Etching-Stop Layers
Authors: Lin Jia Chuan , Zeng Fu Xiang , Wei Jia Na , Liu Chi Ting , Hsu Meng Kai , Hou Hsi Ting
Published: December 2011

Al0.22Ga0.78As/In0.18Ga0.82As/Al0.22Ga0.78As double heterojunction high electron mobility transistors (DH-HEMTs) with gate structures of traditional planar gate (PG), one-stage gamma-gate (1SΓG) and two-stage gamma-gate (2SΓG) formed by using the Al0.22Ga0.78As/In0.49Ga0.51P etch-stop layers (ESL) are simulated and presented in this work. Based on this proposed ESL structure design, the fabrication and implementation of studied DH-HEMT device with 1SΓG and 2SΓG could be expected. Both ΓG-structure devices show the better electric field property compared to PG-device. Simulated results reveal that there are no significant differences in common-source voltage-current characteristics among all studied devices. The obtained drain current density and transconductance of all studied devices are about 220 mAmm-1and 265 mSmm-1. However, the current stability of ΓG-devices with larger bias operation would be improved due to its edge-effect of ΓG extended-region. In addition, the electric field intensity under the gate-footprint is effectively reduced by both studied ΓG structures. The electric field peak value of PG-device is 498 kV cm-1, and it would be reduced down to about 210 kVcm-1and 178 kVcm-1for 1SΓG- and 2SΓG-device, respectively. On the other hand, some frequency property dropping is observed from studied device with 1SΓG or 2SΓG due to the side-edge extension of ΓG-device would create the additional parasitic capacitance. The obtained cut-off frequencies are 15 GHz, 10.5 GHz and 10 GHz for PG-, 1SΓG- and 2SΓG-device (at VGS=+5 V and VGS=-0.75 V), respectively.
Preparation and Analysis of Cotton Nonwoven Film Strengthened by Chitosan
Authors: Jia Shan Shan , Xu Hong , Pei Yao Guo , Luo Jun , Ye Wei , Hu Wen Jun , Zhang Yan Jie
Published: December 2011

The invention of plastic film has brought not only convenience but also environmental pollution to people. To use natural vegetable fiber is the mainly approach to solve the problem. In this paper, the waste cotton fiber was used as raw material and the cotton nonwoven sample was made through wet laying process, after strengthened by chitosan, degradable film was prepared. The performances of the film were characterized and analyzed by testing the strength, air permeability, moisture permeability and other indexes. The results showed that chitosan can be used as strengthening agent, the performances of the film strengthened were improved, and it was degradable.
Organic Light Emitting Diodes with Metallocene Compounds as Cathode Interfacial Layers
Authors: Park Keun Hee , Yeo Dong Hyun , Oh Seung Sik , Kim Hoon Bea , Ha Myung Hoon , Oh Hyo Jin , Park Min Woo , Park Ji Soo , Park Dae Won , Jung Dong Geun , Chae Hee Yeop , Kim Hyoung Sub , Boo Jin Hyo
Published: December 2011

We reported characteristics of OLEDs with the metallocene compounds as cathode interfacial layer between the organic layer and the cathode electrode. The brightness and efficiency of OLEDs with the metallocene compound cathode interfacial layer exhibited higher performance than those of OLEDs without it. The enhancements are attributed to an improved balance of hole and electron due to increased electron injection at the organic layer and the cathode.
The Enhanced Saturation Magnetization of Nanocrystalline (Ni0.5Zn0.5)1-xCoxFe2O4 Ferrite
Authors: Qiu Yi Bing , Liu Yin , Min Fan Fei , Cao Yan , Qiu Tai , Zhang Ming Xu , Pan Wei Ping
Published: December 2011

Single spinel phase nanocrystalline ferrite (Ni0.5Zn0.5)1-XCoxFe2O4was prepared using the spraying co-precipitation method. The coercivity of prepared (Ni0.5Zn0.5)1-XCoxFe2O4 increases with an increasing content of cobalt. The enhancement of the saturation magnetization was observed up to the maximum value of 102.1emu/g as x was 0.5. This can be attributed to the substitution of the Ni2+ and Zn2+ ions with Co2+ ions. This changed the net magnetic moment between the sublattices of structure.
Synthesis and Photoluminescence Property of Tris(8-hydroxyquinoline) Bismuth Rod-Like Structures at Room Temperature
Authors: Wang Hong Liang , Zhang Jun Hao , Qu Zhao Kun , Jia Liang , Wang Jiao Long
Published: December 2011

Tris(8-hydroxyquinoline) bismuth complex has been synthesized with a facile method in a mixed solvent system containing bismuth nitrate and 8-hydroxyquinolineat at room temperature. The molecular formula of the products is speculated by the C, H and N element analysis and thermal gravimetric analysis, and FTIR was also utilized to measure the structure, which further confirms the molecular formula of the products. The observation of FESEM and TEM shows that the morphology of tris(8-hydroxyquinoline) bismuth complexes is rod-like structure. The results of photoluminescence emission indicate that inorganic element plays key roles in the luminescence property. According to the results, we found that the photoluminescence of tris-(8-hydroxyquinoline) bismuth is stronger than that of 8-hydroxyquinoline.
The Time Response of Exponential Doping NEA InGaAs Photocathode Applied to near Infrared Streak Cameras
Authors: Tang Wei Dong , Yang Wen Zheng , Cai Zhi Peng , Sun Chuan Dong
Published: December 2011

An exponential doping NEA InGaAs photocathode is theoretically proposed to apply in the near infrared streak camera. The photocathode time response is calculated and analyzed by using a photoelectron non-steady method. The numerical results show that the excited electrons in the InGaAs active layer is accelerated due to the built-in electric field induced by the exponential doping structure, which shortens the transport time of minority carriers in the photocathode and thus, the time response is greatly improved. In addition, the exponential doping InGaAs photocathode possesses time response of less than 10 picoseconds and near-infrared quantum efficiency of 10%.
Tunable Magnetism and Half-Metallic Stability of Half-Heusler Compound NiMn1-xNbxSb
Authors: Zhou Qing , Wu Bo , Yuan Hong Kuan , Chen Hong
Published: December 2011

By using the first-principles calculations within the density functional theory (DFT), we investigate the electronic structure, magnetism and half-metallic stability of half-Heusler compound NiMn1-xNbxSb. The results showed that the lattice constants and magnetic moments per unit respectively follow the Vegard law and the Slater-Pauling rule well. The most stable half-metallicity occurs at doping concentration x=0.25 due to the Fermi level is situated the middle of the spin-down gap. Our studies also indicate that the competition of hybridization of d-electrons and RKKY-type magnetic coupling plays a dominating role in determining the magnetism.
UV Ageing Test and EIS Study of Fluorocarbon Resin Coatings on Galvanized Sheet
Authors: Wang Lei , An Cheng Qiang , Sun Jie , Yu Hai Yun , Liu Chang Sheng
Published: December 2011

The aim of this study is to study the protection performance of fluorocarbon resin coatings on galvanized sheets with electrochemical impedance spectra(EIS) and scanning electron microscopy (SEM) for UV ageing to simulate nature environment. The results indicated that impedance of the coatings acted as a capacitive character at the early UV ageing stage. the diffusion impedance was shown in low-frequency range, which was attributed to the self-healing effect of the chromate layer to the metal interface. After 2000 hours of ageing in the UV chamber, there is a low impedance values in the impedance spectra. Taking into account defects were found on the film surface on SEM picture, it is easy that the outside corrosive substances meet metal substrate through the coating at the defects.
Structural Design of Rail-Beam Leveler
Authors: Ma Li Dong , Zhou Cun Long , Pan Hai Yan , Wang Yun
Published: December 2011

The requirements of a major industry whose products are rail-beams to level the both sides of rail-beams were analyzed. Some of basic parameters have been computed by the analytical method. The process of roller’s leveling was simulated with explicit nonlinear finite element method, and the results were proved close to those from analytical method. The simulation was applied to an approach to the most suitable rolling reduction. The final conclusion shows that simulation is a powerful way to improve design’s qualities.
Difference between the Measured and Theoretical Value and Theirs Influencing Factors for Heat Transfer Coefficient of Exterior Wall External Insulation
Authors: Tian Yu Lan , Lu Jian Min , Zhang Wen Yan
Published: December 2011

This paper analyzed the actual heat transfer coefficient of exterior wall external insulation, which was detected by temperature controlled hot box-heat flow meter method in Nanjing from March to December, 2010 .Research showed that: impacted by one-dimensional stability heat transfer assumption ,78.27% of test values of the heat transfer coefficient for exterior wall external insulation , are less than the calculated values; under certain circumstance, that the external thermal insulation material(Expandable polystyrene shutter, EPS board for short, and Extruded polystyrene shutter, XPS board for short)are the same, the more stable the wall substrate density and material , the greater the heat storage coefficient is and the smaller the relative detection error will be. When using the same stable wall substrate material, the calculation error of XPS board was significantly better than EPS board’s. The analysis, which is about error influence factors of test value of the heat transfer coefficient of exterior wall external insulation, shows that current temperature controlled hot box-heat flow meter heat transfer coefficient method needs further improved and perfect in order to improve the reliability of its conclusion.
Damage Model for Dissipative Materials with Generalized Non-Linear Strength Theory
Authors: Yu Wei Wei , Guo Xuan
Published: December 2011

This paper builds the formulations of damage model for dissipative materials with generalized non-linear strength theory. The proposed model reflects the internal structural configuration and damage behavioure. The structural evolution parameters are introduced to account for the progressive loss of the internal structure. The proposed damage model is proposed by generalized non-linear strength theory, the capability of the models in predicting behavior of clay has been examined.
First-Principles Study on Mechanical Properties of IVB-Group Transition-Metal Nitrides TiN, ZrN, and HfN
Authors: Wang Jin , Chen Zhi Qian , Li Chun Mei , Wang Fang , Zhong Ying
Published: December 2011

IVB-group transition-metal nitrides are hot research materials due to their high hardness, good thermal stability, and excellent mechanical properties. In this paper, we studied the lattice parameters, elastic properties, electronic structures, and hardness of the face centered cubic TiN, ZrN, and HfN. The research shows that all the three types have excellent elastic properties. According to the result, elastic properties of HfN are the best of the three, as its bulk modulus and shear modulus are 278GPa and 240GPa respectively. With the calculation of electronic density of states, we find that all the three types are metallic. The wide pseudogap in DOS and the large overlap population indicate the strong Ti-N, Zr-N, and Hf-N bonds. The lower value of the density of states on the Fermi level shows that crystal structure of HfN is more stable. That is why the elastic properties of HfN are better than the others, mainly. The calculated hardness of TiN is 23.6GPa, which is the highest.
Study on the Performance Influencing Factor of Epoxy Asphalt Waterproof Cohesive Layer in Steel Deck Pavement
Authors: Zhang De Jia , Ye Fen , Zhou Ji Zhao , Wang Sheng
Published: December 2011

In recent years, epoxy asphalt is used widely in the waterproof cohesive layer material of steel deck pavement. This material has obvious advantages in cohesion, deformation capacity and hot stability. This paper analyses the effects of water and temperature on the performances of epoxy asphalt waterproof cohesive layer by indoor shearing and pulling tests. It has important theoretical significance and practical value for the development and application of epoxy asphalt waterproof cohesive layer material.
Influence of Calcination Temperature on Activity of Hydration Properties of Gangue
Authors: Zhu Jian Ping , Zhang Jian Wu , Zhao Song Hai , Li Dong Xu
Published: December 2011

The mineral structure and hydration activity changes of the Jiyuan gangue calcined at different temperatures were studied in the paper. Differential scanning calorimeter (DSC), X-ray diffraction (XRD) testing, strength testing of cement and Microhardness analysis methods were used to study the thermal activation of coal gangue mineral composition, and macroscopic characterization of the activity of heat-activated coal gangue. The results showed that after heat activation, the destruction of the gangue can be effective in the silicon-oxygen bond, aluminum-oxygen bond, forming amorphous material, and thereby enhanced the activity of coal gangue. Best thermal activation process conditions of Jiyuan gangue is calcined at 800°C for 2h. Adding 40% of the heat-activated coal gangue Activated at this condition to cement, the compressive strength than the same dosage as is the compressive strength of coal gangue increased 106%.
Study of Ground Lateral Flow on Piles Foundation due to Soil Liquefaction
Authors: Yu Wei Wei , Guo Xuan
Published: December 2011

The case studies on the damaged pile foundation caused by lateral flow due to soil liquefaction during the big earthquake were discussed. The distributed load method was utilized to calculate the stress and displacement. The effect of the lateral flow to pile foundation in liquefiable soil also is simulated. Through compared the analysis result to the site dig-investigate report, the mechanism of the damaged pile modes were conjectured very well. the calculated stress and deformation of piles indicated good agreement with the actually observed one. The practicability and availability of the distributed load method was substantiated.
Phase Field Model for Influence of Edge Dislocation on Precipitation
Authors: Huang Chuang Gao , Gao Ying Jun , Huang Li Lin , Tian Jun Long
Published: December 2011

The second phase nucleation and precipitation around the edge dislocation are studied using phase-field method. A new free energy function is established. The simulation results are in good agreement with that of theory of dislocation and theory of non-uniform nucleation.
Research on Solid Wastes of Gangue, Slag, Fly Ash Used as Cement Composite Mixing Materials
Authors: Liao Jian Guo , Ma Qian , Zhang Yi Shun , Song Zhi Yang , Liu Kai Hang , Hu Ya Wei
Published: December 2011

The purpose of this study is to bring the fly ash, coal gangue and slag industrial solid wastes which contain the chemical composition for activation treatment, used as activated composite cement mixing materials, through strength test shows that the compound mixing materials impermeability activation treatment can obviously increase the cement strength. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) analysis results showed that the crystal structure of the mixed material calcined before and after have apparent change. There are lesss hydration products with compact structure of cement hydration 3d. The early strength of aiding composite mixing materials cement improved greatly.
Wavelet-Based Denoising of Vibration Signals for Tool-Edge Wear Detection in High Speed Machining of Inconel 718
Authors: Fang Ning , Srinivasa P. Pai , Edwards Nathan
Published: December 2011

Denoising is an essential step and plays a significant role in tool condition monitoring. In the present study, four wavelet-based denoising techniques are studied and compared, including conventional hard-thresholding, conventional soft-thresholding, generalized soft-thresholding, and soft-thresholding with Stein’s unbiased risk estimate (SURE). The results show that soft-thresholding with SURE generates the lowest mean squared error, and hence is the most appropriate denoising technique for tool-edge wear detection in high speed machining of Inconel 718.
Screening of Yeast with High-Yield Single Cell Protein and Preliminary Optimization of its Culture Codition
Authors: Shi Min , Liang Ming Zheng , Liang Hong Yu , Li Mei , Liao An Ping
Published: December 2011

The protein content of Rhodotorula rubra 2.1817,Candida tropicalis 2.1775 and Geotrichum candidum 2.1175 were assayed by Coomassie brilliant blue methods. Screening the high-yield SCP strains.Then,the cultur condition of the strains were optimizated by single-factor test.It is shown that the high-yield SCP strains was Candida tropicalis 2.1775,the protein content was 32.46%.The optimal factors: inoculum size 10% (V/V),temperature 30°C,shaking 200 rpm,culture time 5 days.
In Situ Quaternized Gel Electrolyte for Quasi-Solid-State Dye-Sensitized Solar Cell
Authors: Dai Yu Hua , Sun Xiao Lei , Wang Jing Lian , Yang Ming Shan
Published: December 2011

A series of copolymers P(VP-HEMA) composed of hydroxyl ethyl methacrylate (HEMA) and 4-vinyl pyridine (VP) were prepared by a solution copolymerization technique. Based on the copolymer P(VP-HEMA) prepared by the content of VP 50%, the amount of AIBN 3% and the optimized liquid electrolyte, a polymer solution electrolyte with concentration of 9.0% was formed. By addition of 1,4-dibromobutane into the solution, the copolymer gel electrolyte with higher conductivity 6.14mS/cm was prepared. Gelation is caused by the quaterisation between the group of pyridine in P(HEMA-VP) and 1,4-dibromobutane. Based on the copolymer gel electrolyte, a dye-sensitized solar cell was fabricated with short-circuit current of 13.62mA/cm2,open circuit voltage of 0.72V, fill factor of 0.5465 and an overall conversion efficiency of 5.24% under irradiation 100mW/cm2(AM1.5).
Improvement of the Properties of CuInS2 Thin Film Prepared in Sulfate System
Authors: Lu Lin , Li Xiao Gang
Published: December 2011

For the purpose of improving the reproducibility and the semiconductor properties of chalcopyrite CuInS2 thin film, potassium hydrogen phthalate (C8H5KO4), as a complex agent, was added into the sulphate bath system. The optimum process parameter for the preparation of CuInS2 thin film was determined by orthogonal experiment method. The effect of C8H5KO4 on the composition and Mott–Schottky behavior of the as-deposited film was studied with electron dispersion spectroscopy (EDS) and alternating current (AC) measurement. It was found that the as-deposited film was p-type semiconductor with the flatband of 0.665 V and the acceptor density of 3.06×1019 cm-3; the addition of C8H5KO4 can effectively enhance the composition stability of the film and decrease its flatband potential and acceptor density.
Thermoelectric Properties of BaxCo4Sb12 Prepared by High Pressure and High Temperature
Authors: Qin Bing Ke , Ji Yong Hua , Li Zhi , Jia Xiao Peng
Published: December 2011

Polycrystalline filled Skutterudite compounds BaxCo4Sb12(0-x-0.5) are synthesized by high pressure and high temperature （HPHT） technique. The thermal conductivity for CoSb3is depressed significantly by Ba-filling combined HPHT technique. The value of 1.25 Wm-1K-1for Ba0.372Co4Sb12is obtained at 633K. The dimensionless thermoelectric figure of merit ZT, increases with temperature increasing and reaches a maximal value of 1.01 at 663 K.
Numerical Simulation and Optimization on Casting Process of Mould Clamping Board Using a Nodular Cast Iron
Authors: Mi Guo Fa , Chen Li Lin , Li Chang Yun
Published: December 2011

A three-dimensional Computer Aided Design (CAD) model of the mould clamping board is established by Pro/E software. The ViewCast program is utilized to study casting processes of solidification and mould-filling in order to design the risers and optimize the casting technology. Based on the solidification simulation, the casting defects such as shrinkage and porosity are forecasted visually in diagrams with the help of ViewCast. Reasonable risers are designed on the basis of the solidification simulation. The mould-filling simulation verify the metal fluid gates the mould smoothly and reposefully. The filling simulation results of initial casting scheme show that this casting technology is improper. The optimized scheme is completed through the filling simulation and a modified casting technology is obtained. The parting gating system is used to pouring the mold of clamping board. The simulation results of optimized scheme indicate that the shrinkage are eliminated effectively and the metal fluid fill the mold smoothly. Experimentally, the casting confirms that the optimized method is very useful in reducing the casting defects and improving the product quality.
First-Principles Study of the Properties of Clean and Ni-Doped TiC/Fe Interfaces
Authors: Xiao Zhi Gang , Wu Yi , Shen Yu Fang , Zou Zheng Guang , Long Fei , Liu Kai
Published: December 2011

First-principles plane-wave pseudopotential calculations of the electron structure and energetics of the interfaces of clean and Ni-doped TiC/Fe are reported. We predicted the atomic structure, bonding, and the interface binding energy of TiC(100)/Fe(100) and TiC(100)/Fe(110). By comparing the interface bonding energy and the total charge density distribution, the interface have priority to combine in TiC(100)/Fe(100) and TiC(100)/Fe(110) ways, where the former’s interface binding energy is higher. So the structure of TiC(100)/Fe(100) is more stable. The doped Ni atoms have preferential access to Fe-based body and form FeNi alloy, and enhance the interface bonding energy, thus effectively reducing the system energy of TiC(100)/Fe(100) and TiC(100)/Fe(110) interfaces, increasing the bonding strength and stability of interfaces of the composite materials.
Preparation and Performances of Amino-SiO2 Filled Cellulose Film
Authors: Wang Hua Shan , Zheng Li Xing , Chuai Cheng Zhi
Published: December 2011

Coupling agent KH-550 and KH-792 were used for surface modification of fumed silica to get amino group. And then the un- or modified SiO2blended with cellulose was added into N-methyl-morphine-oxide (NMMO), a kind of casting solvent, to form the cellulose solution for preparation of films. The modified film was characterized by fourier transform infrared(FTIR), scanning electron microscopy(SEM), mechanical tester and oxygen permeation analyzer. The results showed that the modified SiO2can be more evenly dispersed than that unmodified. The un- and modified SiO2all can improve the mechanical properties and oxygen permeation of cellulose film when the filled content is about 2wt% and the KH-792 is the best.
An Investigation on the Electrochemical Cycle Stability of La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1 (x = 0-0.2) Alloys Prepared by Melt Spinning
Authors: Zhang Yang Huan , Liu Xiao Gang , Chen Le Le , Ren Hui Ping , Cai Ying , Zhao Dong Liang
Published: December 2011

In order to improve the electrochemical cycle stability of the La-Mg-Ni system A2B7-type electrode alloys, La in the alloy was partially substituted by Zr. The melt-spinning technology was used for preparing La0.75−xZrxMg0.25Ni3.2Co0.2Al0.1(x = 0, 0.05, 0.1, 0.15, 0.2) electrode alloys. The influences of both the substitution of Zr for La and the melt spinning on the structures and the electrochemical cycle stability of the alloys were investigated in detail. The structure analysis of XRD, SEM and TEM reveals that the as-cast and spun alloys have a multiphase structure, composing of two main phases (La, Mg)2Ni7and LaNi5as well as a residual phase LaNi2. The substitution of Zr for La facilitates to form a like amorphous structure in the as-spun alloy without altering the structures of two major phases. The electrochemical measurement indicates that both the substitution of Zr for La and the melt spinning remarkably improves cycle stability of the alloys. The capacity retaining rate (S100) of the Zr0.2alloy at 100th charging/discharging cycle is enhanced from 76.69 to 85.18% by growing spinning rate from 0 (as-cast was defined as the spinning rate of 0 m/s) to 30 m/s. And that of the as-spun (10 m/s) alloys is increased from 69.25 to 83.09% by rising Zr content from 0 to 0.2.