bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Acrylic Acid Treated Rice Husk Silica on Properties of Poly (butylene adipate-co-terephthalate) (PBAT) Composites
Authors: Phosee Jirapa , Wittayakun Jatuporn , Suppakarn Nitinat
Published: December 2011

In this work, rice husk silica (RHS), obtained from rice husk waste, was used as a reinforcing filler for preparing PBAT composites. In order to facilitate interfacial adhesion between PBAT matrix and RHS filler, the RHS surface was treated with acrylic acid (AA) at a reaction temperature of 140°C. The RHS to AA weight ratio was fixed while the reaction times were varied between 3-24 h. TGA results and FTIR spectra indicated the appearance of AA molecules on RHS surface. Untreated RHS (U-RHS) and AA treated RHS (AA-RHS) were used to produce PBAT composites. The filler content was 30 wt%. Tensile properties and impact strength of AA-RHS/PBAT composites were higher than those of U-RHS/PBAT composite. As revealed by SEM micrographs, AA-RHS was well dispersed in PBAT matrix and the interfacial adhesion between RHS surface and PBAT matrix was improved.
Supramolecular Polymers for Potential Biomedical Applications
Authors: Li Jun
Published: December 2011

The phenomena of molecular self-assembly have inspired interesting development of novel functional materials. We have been focusing on developing novel polymers with the ability to self-assemble into novel supramolecular structures, which can function as biomaterials for potential drug/gene delivery and tissue engineering applications. The key components in our macromolecular self-assembling structures include the biodegradable and biocompatible microbial biopolyesters, poly (β-hydroxyalkanoates), and the macrocyclic polysaccharides, cyclodextrins. A series of novel block copolymers and interlocked supramolecular architectures were designed and synthesized. They were characterized in terms of their molecular and supramolecular structures, as well as their properties and functions as biomaterials for potential drug and gene delivery, and tissue engineering applications. Amphiphilic block copolymers of different chain architectures composed of poly [(R)-3-hydroxybutyrate] as hydrophobic segments, and poly (ethylene glycol), poly (propylene glycol), or poly (N-isopropylacrylamide) as hydrophilic segments were synthesized. They could self-assemble to form stable micelles, nanopatterning thin films, and thermo-sensitive hydrogels, which were demonstrated to be promising potential biomaterials for controlled and sustained delivery of drugs and tissue engineering scaffolding materials. The self-assembly of block copolymers with cyclodextrins resulted in supramolecular hydrogels and cationic supramolecules, which were used as injectable drug delivery systems, and novel polymeric gene delivery vectors.
Synthesis and Photocatalytic Properties of Bi2Ti2O7 Nano-Powders
Authors: Su Xiao Li , Zhang Ying Chun
Published: December 2011

Bi2Ti2O7 nanopowders were prepared using bismuth nitrate and tetrabutyl titanate as starting materials by sol-gel method. The decomposition of precursors, crystal structure and microstructure of the sample was characterized by TG/DTA, XRD and TEM techniques, and the results indicate that the sample is well-crystallized pyrochlore Bi2Ti2O7 phase with spherical shape and an average grain size of 30 nm. Photocatalytic activity of Bi2Ti2O7 powders was evaluated by photodegrading methyl orange solution. The result shows that Bi2Ti2O7 has a higher photocatalytic activity than TiO2 (mixed with rutile and anatase) with the same concentration, and when concentration of Bi2Ti2O7 increased to 9g/L, half-life period T1/2 is 0.97h, then methyl orange solution can be completely degraded in more than an hour.
Preparation of LiMn2O4 by a Solution Combustion Synthesis Using Acetic Salts and Acetic Acid as Starting Materials
Authors: Wang Bao Sen , Guo Jun Ming , Guo De Wei , Liu Gui Yang , Zhang Li Li
Published: December 2011

Spinel LiMn2O4was synthesized by a solution combustion synthesis using lithium and manganese acetate as raw materials and acetic acid as fuel. The phase composition and micro morphology of the as-prepared products were determined by X-ray diffraction (XRD) and scanning electric microscope (SEM). The electrochemical performance of the products was tested by using a coin-type half battery versus lithium metal foil as anode material. XRD analysis suggested that the main phase of the products was LiMn2O4, but there was little impurity Mn2O3in the products. The relative content of Mn2O3was decreased gradually when the molar ratio of Li:Mn: acetic acid increased from 0.5:1:0.5 to 0.5:1:2, but increased again when the molar ratio of Li:Mn: acetic acid was 0.5:1:2.5. The purest product could be prepared when the molar ratio of Li:Mn: acetic acid=0.5:1:2. SEM investigation indicated that the typical crystal structure could not be investigated from the as-prepared products, and the particles were badly agglomerated. Electrochemical performance tests indicated that the specific capacity of the purest product was 108mAh/g. After 30 cycles, the capacity faded only 22% at the current density of 50mA/g, and the average charge/discharge efficiency was ~96%. At the current density of 75mA/g, the initial specific capacity of the purest product was only 72mAh/g, but after 30 cycles, the capacity retention was >92%, exhibiting a good cycling performance.
Bismuth Ferrite Nanopowders Prepared by Sol-Gel
Authors: Fu Chun Lin , Huo Meng , Cai Wei , Deng Xiao Ling
Published: December 2011

BiFeO3 powders were prepared by sol-gel process and calcined at different temperatures. The DTA curve shows an obvious exothermic peak near 480.5°C, the temperature close to BiFeO3 formation temperature, which is agreement with the XRD results (450°C). After calcining at 600°C for 1h, XRD spectra has the emergence of several sharp diffraction peaks, compared with the standard XRD spectrum of the crystal BiFeO3. As the calcining temperature increased, the diffraction peak intensity of the XRD spectra of BiFeO3 gradually increased and the diffraction peaks became sharply, indicating that the grain size gradually became larger. There is a clear endothermic peak near 825.1°C, which is the α phase to β phase transition from the knowledge of the phase diagram and in good agreement with the reported Curie temperature.
Preparation of Flower-Like ZnO Micro-Sphere Powders and their Surface Wettability Modification
Authors: Li Bing , Liu Chang Song , Qi Yu Bin , Cao Da Chun , Wan Yong
Published: December 2011

Three-dimensitional flower-like ZnO powders were prepared by using a simple aqueous solution method. Their surface wettability was modified via some long chain alkylsilanes with low surface energy. The microstructures and the wettability properties were studied by scanning electron microscopy (SEM), X-ray diffractometer (XRD) and contact angle measurement (CAM). The ZnO powders are spheric and are about 5 micrometers in diameter. The boundary of the microspheres are not smooth, but petaliform in nanoscale, which demonstrate a hierarchical microstructure. The as-synthesized powders have a superhydrophobicity with water contact angle of more than 150°, and have a high adhesion to water. After modified by alkylsilanes, however, the ZnO powders demonstrate a strong anti-adhesion to water. When modified by fluorinated alkylsilanes, the surface of ZnO microspheres had a water contact angle up to 170°. Also, the water droplet could bounce against the surface just like a spring ball, and there are not any water traces left when the water droplets contact the surfaces of ZnO powders. The results provide a simple method to repel the water wetting and will be helpful to disperse the powders especially in a humid environment.
Phase Assembly of Ti2SnC Powders
Authors: Guan Chun Long , Liu Guo Qin , Shan Ying Chun
Published: December 2011

Ti2SnC powders (Ti: Sn: C =2: 1.2: 1, mol.%) were synthesized by pressureless sintering in argon in the temperature range of 600 to 1050°C using Ti, Sn and graphite powders as the initial materials. The phase relationships during reaction in the ternary system Ti-Sn-C have been investigated. The products for identification and analysis were characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). The reaction path for the formation of Ti2SnC can be described in the following steps. Sn melted at 230°C, which provided a favorable liquid circumstance for the reactions between Ti and Sn to form Ti-Sn intermetallic compounds. Results showed that Ti6Sn5 and Ti5Sn3 intermediate phases were formed in turn with increase of temperature. Up to 1050°C, with consumption of Ti5Sn3 phases completely, the amount of Ti2SnC increased significantly. Single phase Ti2SnC with small amount of TiC was produced. Combined with the results of differential thermal analysis (DTA) and X-ray diffraction (XRD), it is revealed that Ti2SnC phase is formed by the reaction of Ti–Sn intermetallic compounds, Ti and graphite. In addition, the reaction equations of the process from 230 to 1050°C were given.
Preparation of Cu-Zn Alloy by Different High Energy Ball Milling
Authors: Wang Kai Jun , Cai Xiao Lan , Wang Hua , Hu Jin , Zhang Yun Feng
Published: December 2011

Cu-Zn alloy was prepared by high energy ball milling of elemental copper and zinc by the Simoloyer attrition mill, the different parameters such as milling time, ball-to-powder ratio and rotational speeds were analyzed. The results show that the different Cu-Zn alloy phase can be produced by different ball milling parameters, It has been found that milling time is highly significant to refining process, and the ratios of ball to powder are also benefited to the new phase form.
Low Temperature Sintering and Microwave Dielectric Properties of Ba4Nd9.33Ti18O54 Ceramics Doped with Crystallizable Glass
Authors: Zuo Ru Zhong , Lv Yang , Wu Yang , Yue Zhen Xing
Published: December 2011

The effect of CaO-B2O3-SiO2 glass on the densification, microstructure and microwave dielectric properties of Ba4Nd9.33Ti18O54 ceramics was investigated in this work. It was found that the addition of a few amount of glass (≤2%) could effectively decrease the sintering temperature owing to the viscous sintering. However, locally porous structures were formed when overmuch glass was added because of enwrapped air bubbles and rapid grain growth. In addition, the amount of remaining glass after sintering could be decreased due to the re-crystallization of CaO-B2O3-SiO2 glass. Sol-gel derived Ba4Nd9.33Ti18O54 ceramics containing 2 wt% glass can be well densified at 950°C and exhibit good microwave dielectric properties of εr=68 and Q×f=7400 GHz.
Ferroelectric Properties of Bismuth Titanate Ceramics by Dy3+/V5+ Substitution
Authors: Huang Chong Qing , Chen Min , Mei X.A. , Sun Y.H. , Liu J.
Published: December 2011

The ferroelectricity of Bi3.25Dy0.75Ti3O12(BDT), and Bi3.25Dy0.75Ti2.97V0.03O12(BDTV) ceramics prepared at 1100°C by a conventional ceramic technique was investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BDT ceramics are 15 µC/cm2and 64kV/cm, respectively. Furthermore, V substitution improves the Prvalue of the BDT ceramics up to 23 μC/cm2, which is much larger than that of the BDT ceramics. Therefore, co-sustitution of D and V in Bi4Ti3O12(BIT) ceramic is effective for the improvement of its ferroelectricity.
Ferroelectric Properties of Bi3.25La0.75Ti2.97V0.03O12
Authors: Liu J. , Chen Min , Mei X.A. , Sun Y.H. , Huang Chong Qing
Published: December 2011

Bi3.25La0.75Ti2.97V0.03O12(BLTV) ceramic were prepared by solid state reaction. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed plate-like grains with random orientation. BLTV caused a large shift of the Curie temperature ( TC) of Bi4Ti3O12(BIT) from 675°C to 395°C. The remanent polarization and the coercive field of the BLTV were 31μC/cm2and 54kV/cm at an electric field of 90kV/cm, respectively. Furthermore, the dielectric permittivity and dissipation factor were 300 and 3×10-3at 1MHz, at 1V and at room temperature, respectively. These ferroelectric properties of BLTV are superior to V-doped Bi4Ti3O12(~20μC/cm2and 80kV/cm) and (Sr, Ta)-doped Bi4Ti3O12(~12μC/cm2and 71kV/cm) ceramics. In addition, the dense ceramics of BLTV could be obtained by sintering at temperatures 100─200°C lower than those of the SrBi2Ta2O9system.
Preparation and Gas-Sensing Properties of CdFe2O4 Semiconductor Materials
Authors: Yang Liu Fang , Wang Yu Lin , Wang Qing Hui , Yi Xu Xiao
Published: December 2011

The gas-sensing materials, CdFe2O4, were prepared by inverse titration chemical co-precipitation with FeSO4⋅7H2O and CdCl2⋅2.5H2O. After calcinations at 300° ~ 700°C for 1h, respectively, n-type semiconductor gas-sensing materials with inverse spinel structure were obtained. Effects of the calcining temperature on the phase constituents and microstructure were characterized. The crystallite size of powders sintered at 700°C for 1h is 82 nm and dispersity good. Sensors based on CdFe2O4 were fabricated, and the gas-sensing properties were determined for using reducing gases. The results demonstrated that the sensors based on CdFe2O4 had good sensitivity and good selectivity to C2H5OH at 400°C. The difference in response for various tested gases might be attributed to absorption of reducing gases and reaction between these gases and the absorbed oxygen.
Preparation and Properties of Oxidized Graphene (OG)/Epoxy Resin (EP) Composite via Ultrasonic Oscillation
Authors: Gao Qun , Ouyang Chun Fa , Shan Xiao Qian , Shi Yu Tao , Wan Ajun , Li Wen Tao
Published: December 2011

The influence of ultrasonic oscillation process on the performance of oxidized graphene (OG) /epoxy resin (EP) composite is studied. The results show that the oscillation process can greatly improve the tensile strength, shear strength and hardness of EP, as well as it’s morphology, for the compatibility of EP with OG is greatly improved after oscillation. OG can improve the dielectric constants of EP to some extent, while increase the tensile strength at low content, decrease with adding more OG. The tensile strength of EP is 19.32MPa and the dielectric constants 1.73 with 3/1000 content of OG. The morphology of the EP shows that the fracture surface of the composite is layer shape while the surface of EP is smooth, indicating OG change the structure of EP after cross-linking reaction.
Thermodynamic Analysis of Aluminum Oxide-Coated Titanium Didoxide
Authors: Wang Yun , Yan Ji Kang , Gan Guo You , Du Jing Hong , Yi Jian Hong
Published: December 2011

In order to improve the dispersion of TiO2, use the surface coating technology to form the aluminium ion film on the surface of TiO2, so as to achieve the aim of modification. Use the aqueous solution sedimentary drying method to make the alumina coating experiment under as certain technical condition, use the test like the scanning electron microscopy and transmission electron microscope, etc to analyze the coating powder’s dispersive and coating situation. The paper started from the angle of ion sedimentary reaction equilibrium, made the thermodynamics analysis on the coating on the surface of TiO2 and got the [Al]T-pH relationship diagram about the aluminium ion, and then confirm the PH extent for the aluminium ion’s completed sedimentation. The result indicated that, when the PH value reached from 8 to 12, the aluminium ion would completely precipitate.
Crystal Structure and Thermal Expansion of Ge-Doped Mn3CuN
Authors: Yan Xue , Hua Z. , Liu J. , Li Bin , Cheng X.
Published: December 2011

The Ge doped Mn3CuN powder was synthesized using gas-solid reaction method with manganese, copper, germanium powders and N2 gas as raw material. The phase constitute of the as-prepared powder was characterized using X-ray diffraction (XRD). The intrinsic and macro thermal expansion coefficients of the powder were measured by in-situ X-ray diffraction at different temperatures and TMA, respectively. The crystal structure of the powders was analyzed using Rietveld refinement method. The results show that the pure Mn3(Cu0.5Ge0.5)N powder can be prepared via the gas-solid method at 850 °C. The crystal structures of Mn3(Cu0.5Ge0.5)N and Mn3CuN both have the antiperovskite structures. The intrinsic and macro thermal expansion coefficient of Mn3(Cu0.5Ge0.5)N powder is-16.8×10-6K-1 and-17×10-6K-1, respectively. The temperature range with negative thermal expansion is from-80 °C to 50 °C.
Observation Technique of Internal Microstructure of Micro-Powder by Electron Microscopy
Authors: Li Zheng Min , Jiang Bing , Zhai Chen Xi , Chen Zhi Wei , Feng Liu , Yu Yuan Zhang
Published: December 2011

Two observation techniques of internal microstructure, including hole and second particle, of micron scale powders have been established and applied to frangible and tough powders. One is that powders were embedded in epoxy resin, sectioned by an ultramicrotome, then observed by using the transmission electron microscopy (TEM) in turn; another is that the fracture of powders were observed by using the scanning electron microscopy (SEM).
Drying Model of Paste Materials in Fluidized Bed with Inert Particles and Immersed Heating Tubes
Authors: Yao Bi Qiang , Zhu Xue Jun
Published: December 2011

The mechanism of drying paste materials was investigated in a fluidized bed with inert particles and inner heats. A mathematical model is proposed to predict the specific water evaporation. The drying properties of dryer can be predicted based on the correlation equations. The drying of paste CaCO3materials was industrial-mode experimentally carried out in a fluidized bed with inert particles and immersed heating tubes. The paste material was spray droplet in sizes range of 200~400μm with pressure nozzles or air-blast nozzles, and spray to the surface of inert particles, and the feasible drying conditions were researched. The feasible drying parameters, operation parameters and equipment parameters were researched. The results show that this drying technology can be enhanced the heat transfer and the paste materials of high viscosity can be effectively distributed into the fluidized bed, well distributed temperature in beds, large elasticity of operation, the low energy consumption. The new drying equipment has high drying capacity, small equipment size. The results can provide important meaning on theory and instructing practice for developing the new drying technology with high drying efficiency and low dissipation of energy.
Synthesis of Platelet Alumina Powders
Authors: Liang Yan Yuan , Chen Da Ming , Tong Jian Feng
Published: December 2011

Platelet alumina powders have been synthesized by introducing AlF3 as crystalline transformation additive. The influence of the additive contents on the phase transformation of the start material Al (OH)3 was studied by SEM, the effect of calcination temperatures on the phase transformation and microstructure of alumina powder were investigated by TG-DSC, XRD and SEM. The results indicate that uniform platelet powders could be abtained while more than 15% AlF3 was introduced. When the calcination temperature higher than 1100°C pure α-Al2O3 could be synthesized, comparing to the tranditional preparation of platelet alumina powders, the remarkable advantages of the method are low calsination temperature, small particle size and simple process.
Barium Zirconium Titanate Powders Prepared by Sol–Gel Method
Authors: Deng Xiao Ling , Guo Dong Jiao , Cai Wei , Fu Chun Lin
Published: December 2011

Barium zirconium titanate, Ba (Zr0.20Ti0.80)O3(BZT) powders were prepared by sol-gel method. These powders were characterized by thermal gravimetric and differential thermal gravimetric analysis (TG-DTA), X-ray diffraction (XRD). The grain size and lattice constant were determined. The decomposition of the precursors was monitored by TG-DTA. XRD patterns reveal that BZT powders heat-treated at 800°C present single phase with perovskite type cubic structure. The average particle size of the BZT powders is about 25 nm.
Preparation of Zn3Nb2O8 by Chemical Co-Precipitation
Authors: Ding Yao Min , Dai Jian Qing , Xia Jing Bing , Chen Wen Guo , Hu Zhi Gang
Published: December 2011

Fine powder of Zn3Nb2O8 was prepared by chemical co-precipitation using KOH, Nb2O5 and ZnSO4·7H2O as raw materials. Laser particle analyzer was used to investigate the precursor. It showed that the average size (D50) was 3.13μm, and the particle distribution ranged from 1.82µm to 4.47µm. TG-DTA and XRD showed that, the precursor yielded Zn3Nb2O8 ceramics by calcined at 850°C, which was much lower than 1100°C, at which Zn3Nb2O8 ceramics could be obtained by traditional solid state method. The sintering of as-obtained powers with Cuo-Bi2O3-V2O5 sintering aids results in producing Zn3Nb2O8 ceramics with s density 94.20% of the theoretical, and a product up to 19.83 (at 30MHz) at sintering temperature 950°C.
Design of Reconstruction and Extension Projects of the Wastewater Plant of an Ordnance Repairing Factory
Authors: Li Jing Miao , Liang Chen
Published: December 2011

In order to improve the treatment capacity and effluent quality of the wastewater plant of an ordnance repairing factory in Guangzhou City, China. The wastewater treatment process was modified and the construction was extended. The factory mainly repairs military equipments in air force, discharges 1200 m3/d wastewater .The current operating conditions of original wastewater treatment equipments are unstable and the effluent quality is substandard, and that the capacity is inadequate.By upgrading the technology and tapping the potential of original process, enlarge the primary treatment capacity to 500 m3/d and build another treatment process with the treatment capacity of 700 m3/d.The total treatment capacity is adequate and effluent quality meet the demands of criteria A specified in DB44/26-2001 of Guangzhou.
Application of Bailey Method for Aggregate Grading Design of Continuous Dense Gradation Asphalt Mixture
Authors: Zhu Wei , Li Hong Zhen , Ma Shi Rang , Liu Da Bin
Published: December 2011

On the base of discussion and analysis of Bailey method for Aggregate Grading Design, the paper expounds particularly how to design Aggregate gradation of continuous dense gradation asphalt mixture by a accurate computational procedure, with the example of AC-20(asphalt cement 20 version) continuous dense gradation asphalt mixture design. It will benefit for designer to design graduation well. This also suggests using three ratios, [CA] Ratio, [FAc] Ratio and [FAf] Ratio, to analyze composite gradation. Thus the designed mixture has good rutting resistance and endurance. The key technologies about this design method were studied. In the context of the same asphalt binder and aggregate, two kinds of AC-20 aggregate gradations have been designed by using Bailey method and the routine method. With these two methods, several kinds of specimens for pavements performance tests has been made at separate optimum asphalt contents. These experiments have shown that the asphalt mixture designed by Bailey method has a better rutting resistance at high temperature, crack resistance at low temperature and durability than the one designed by the routine method. In these experiments, the dynamic stability is enhanced by one time to 6749 times/mm in rutting Test; the Tensile Strength Ratio (TSR) is improved greatly in Water Susceptibility Tensile Strength Ratio Test, which is much larger than the required value in the specification; the maximum bending and tension strain is also enhanced. As a result, Bailey method can be widely used in aggregate grading design in practical engineering.
Survey on Micro-Grid Technology
Authors: Ma You Jie , Shi Li Guo , Zhou Xue Song
Published: December 2011

The micro-grid technologies become one of key spots in the research on distributed energy systems. In this paper, the components, systemic structure and operation modes of micro-grid are presented. From the viewpoint of technical connotation, the present research situation of key technologies for the micro-grid is reviewed. These technologies include new power electronic converter technologies, fault detection and protection, communication technologies, planning and design of micro-grid, as well as issues related to operation control and energy management such as supervisory and control architecture, control strategies and approaches, ancillary services, operation specification, modeling and simulation research in system level and unit level and micro-grid economic evaluation. The authors also point out that the optimal design of micro-grid topology and optimal configuration of distributed energy units are of significance for the implementation of maximum benefit of the whole micro-grid. Besides, the effective economic evaluation of micro-grid is a topic to be researched in detail.
Design of Matrix Converter Vector Control System Based on DSP and CPLD
Authors: Jiang Xiang Ju , Liu Er Lin
Published: December 2011

Matrix converter is a kind of power electric converter by AC-AC transformation with its excellent input and output characteristics.After analysis of matrix converter system structure in the paper,a digital signal processor based on DSP and CPLD is designed. The design includes the hardware structure and the program flowsheet.DSP and CPLD is the core of the matrix converter - Asynchronous motor vector control system, including system main circuit, other peripheral hardware circuit, control and protection circuits, software design process and so on. The hardware control strategy and software realization scheme of the system are discussed in detail. The experimental results verify that the control strategy of the system is valid and the design of the software and hardware are reasonable.
The Mix Design of Low Strength High Flowing Concrete with Low Cement Content Prepared by Manufactured Sand
Authors: Liu Zhan Ao , Zhou Ming Kai , Chen Xiao
Published: December 2011

Aiming at the engineering status of the shortage of natural sand and the contradictory between workability and strength surplus emerging in the design of low strength high flowing concrete (LHC), this paper has proposed a mix design method of LHC with low cement content prepared by manufactured sand (MS).And then verifies the feasibility of the method through experiments. Tests on slump, compressive strength and chloride ion diffusion coefficient were carried out and the results indicate that LHC with low cement content prepared by MS can be successfully produced using this method. Concrete designed by this method has low cement consumption and has utilized MS to replace NS as well as made full use of the industrial by-products of stone fines and fly ash. As a result, it is economical and ecological.
Finite Element Simulation Model for High Temperature 4H-SiC Devices
Authors: Habib Hassan , Wright Nicolas G. , Horsfall Alton B.
Published: December 2011

In the last decade, or so, many prototype Silicon Carbide devices and circuits have been demonstrated which have surpassed the performance of Silicon for the ability to function in extreme environments. However, the commercialisation of SiC technology now demands high performance and energy efficient miniaturised devices and circuits which can operate on the limited power resources available in harsh and hot hostile environments. This leads to refining, experimenting and perhaps re-designing devices which can rightly claim their share in the current Si dominant market. Consequently, there is a need for accurate simulation models for device engineers to understand device behaviour, examine performance trade-offs and verify the manufacturability of the design. This paper reports the first comprehensive study on the development and validation of high temperature 4H-SiC Technology Computer Aided Design (TCAD) Finite Element simulation model for low power applications. The model is based on 4H-SiC physical and material properties and is validated by high temperature 4H-SiC lateral JFET data, fabricated and characterised by our group at Newcastle University.
Application Conditions on Acoustic Emission (AE) Technique Monitoring Coal and Rock Dynamic Disasters in Mines
Authors: Li Jian Gong , Liu Hong
Published: December 2011

The application conditions of acoustic emission technique in mines are the base of acoustic emission monitoring coal and rock and gas dynamic disasters, which must be studied before acoustic emission monitoring gas dynamic disasters in the field begins. Based on the stress wave propagation theory, quality factor Q theory, and many field tests, the acoustic emission propagation theoretic model is established, and the acoustic emission propagation laws in coal and rock with the different protodyakonov coefficient are obtained. Based on these propagation laws and monitoring techniques in the field, the application conditions of acoustic emission monitoring dynamic disasters in the coal and rock are preliminarily given, which can be described that, when the protodyakonov coefficient of coal is smaller than 0.2, acoustic emission sensors must be installed in roof rock; when the protodyakonov coefficient of hardness of coal is not less than 0.2, acoustic emission sensors can be installed in the roof rock or in the coal. These conclusions support the theoretic and testing base for the further study on the acoustic emission forecasting dynamic disasters technique.
Evaluation of Low Temperature Performance for Diatomite Modified Asphalt Mixture
Authors: Zhang Yi Bo , Zhu Hong Zhou , Wang Guo An , Chen Tuan Jie
Published: December 2011

According to the low temperature disease on asphalt pavement in the areas of cold and large temperature difference between day and night, conventional index test and low temperature bending creep test were used to analyze the influence of diatomite dosage on the low temperature performance of diatomite modified asphalt, and the mixture’s low temperature bending test was applied for verification. Test results show that after diatomite’s addition into asphalt, equivalent brittle point reduces significantly, ductility test cannot estimate low temperature performance very well, stiffness modulus increases and relaxation ability decreases; meanwhile, peak value of stiffness modulus and strain energy of asphalt mixture can be found, the low temperature crack resistance is enhanced; optimum dosage of diatomite is 13%. So, the low temperature performance evaluation method of diatomite modified asphalt mixture through BBR’s low temperature performance evaluation on diatomite modified asphalt remains to be discussed.
Abrasive Wear Behaviour of MoB/CoCr Cermet Coatings under Different Parameters
Authors: Chen Xiao
Published: December 2011

In this study, abrasive wear behaviour of MoB/CoCr coating deposited by low pressure plasma spraying (LPPS) was investigated. The properties of microhardness and bond strength of the MoB/CoCr coatings were tested. The abrasive wear properties were evaluated by MLS-225 wet sand rubber wheel tester. The results show that MoB/CoCr coatings are dense and have excellent mechanical properties with high microhardness (930HV0.2) and bond strength (71MPa). The MoB/CoCr coatings have high abrasive wear resistance property.
Development in Wear Resistance of Fe-0.7Cr-0.8Mn Milling Balls through In Situ Reinforcing with Low Weight Percent TiC
Authors: Nasrabadi Hossein Beygi , Shaterian M. , Tohidlou E. , Rahimipour M.R.
Published: December 2011

In order to increase wear resistance of Fe-0.7Cr-0.8Mn cold work tool steels, low weight percentage of Ti incorporated to the alloy and subsequently, because of high affinity between additive titanium and carbon content in this alloy, low weight percentage of TiC in situ formed in matrix. These composites can be used as the milling balls in mining and cement industries because of their improved wear resistance. Formation, shape, size and distribution of TiC particles within the matrix were studied by optical microscopy equipped with image analyzer, optical emission spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Also microhardness and density of the samples measured. Abrasion wear tests were carried out using a pin on disc type machine. An experimental design based on Taguchi method was applied to investigate the effect of TiC content, applied load, sliding distance and roughness of SiC abrasive paper on wear behavior of samples. The results show that by reinforcing the Fe-0.7Cr-0.8Mn steels with low weight percentage of TiC, wear resistance of these kind of milling balls significantly increases. Sliding distance has the most influence on wear rate of samples, also weight loss of samples decreases as sliding distance, applied load and roughness of grinding decreases.
Study on Wear and Friction Resistance of CrTiAlMoN Coatings Deposited by Magnetron Sputtering
Authors: Wang Tao , Zhang Guo Jun , Jiang Bai Ling
Published: December 2011

The present research aims to synthesize a nanoscale multilayer CrTiAlMoN hard coating for the modification of wear and friction performance, as compare to CrTiAlN coatings. CrTiAlMoN coatings were deposited on 1045 carbon steel substrates by magnetron sputtering at different Mo target current. The wear and friction resistance were characterized by pin-on-disc test. When a WC-Co ball was used as the counterpart, the coefficients of friction of CrTiAlMoN coatings were found to decrease with the increase of Mo target current, with the lowest value (0.34) being only one half that of CrTiAlN coating (0.76). The combination of high hardness above 36GPa and low coefficients of friction reduces the specific wear rate of the CrTiAlMoN coatings to only 10% of CrTiAlN coatings. When tested against a bearing steel ball, results demonstrate that the effect of Mo on reducing friction of the CrTiAlMoN coatings is not significant and even negative due to adhesive wear.
Research on Effect of Erbium Salt in the Anodization of Aluminum
Authors: Liu Xiao Zhen , Zhu Liang Wei , Wang Gang , Song Ling Ling , Tang Xiao Yun
Published: December 2011

Erbium salt was used as additives for the first time in preparing anodic aluminum oxide (AAO) films to improve its performance. AAO films were prepared from a 15 vol. % sulphuric acid solution containing erbium salt by anodization method; the effects of concentration of erbium on microhardness and thickness of AAO film were researched, respectively. The effect of heat treatment temperature on structure of AAO film was researched. AAO films were characterized by XRD, EDAX and SEM techniques, respectively. The microhardness and thickness of AAO film were 378.5HV and 82μm respectively, which were higher 12.99% and 17.14% than those of the film prepared in electrolyte of nothing addition erbium salt respectively. The aperture of AAO film was more uniform and the surface of AAO film was smoother than those of films prepared in electrolyte of nothing addition erbium salt. The apertures of AAO film were in 25~30nm. There was not erbium in AAO film. AAO films were amorphous when heat treatment temperatures of AAO film were below 800°C, when heat treatment temperature of AAO film were 850°C and 1000°C respectively, and AAO films were γ-Al2O3 and α-Al2O3 film respectively.
Study on the Experiment of Adsorption Cadmium (II) with Insoluble Starch Xanthate
Authors: Song Xiu Ling , Qian Hui
Published: December 2011

Insoluble starch xanthate (ISX) is made with the potato starch and can be used for the treatment of cadmium-containing waste water. The performance of treatment and the influence factors with ISX made in this experiment are studied in this paper. It is shown that the removal rate of cadmium ion in wastewater can reach over 96%, when pH value of reaction liquid is 8.0, the adsorption time is 0.5h, and the concentration of cadmium ions in waste water is 30 mg·L-1.The adsorption mechanism was also discussed. It is shown that ISX promises to be a new treatment adsorbent to wastewater containing the low concentration cadmium. There are some merits with ISX: the smaller recruitment; better processing effect and so on. It is with chemical adsorption that wastewater containing cadmium is treated by insoluble starch xanthate.
An Research on Self-Fused Alloy Coating by High Frequency Induction Treatment
Authors: Han Gui Quan , Zhang Zeng Zhi
Published: December 2011

Cold adhesion precoating and then induction fusing, as a new technique of preparing self-fused alloy coating, is presented. The workpiece was precoated with Ni60 powder by an adhesion agent. The precoating dried was heated by a high frequency induction with 100kw output power, 250kHz frequency. Its thermomagnetism, thermal resistivity and induction refusing mechanism were analysed to determine the technological parameters. Comparing the microstructures and the properties of the coatings by cold adhesion, thermal spraying and laser refusing, we may conclude that: (1) One side of the workpiece should be preheated to 200°C before induction, and the range of frequency induction should be selected as 200~250kHz. (2) The microstructure of the coating by cold adhesion is superior to that by thermal spraying, but the particle size range should be 0.047~0.044mm (200~320 meshes). (3) The corrosion resistance of Ni60 coating by cold adhesion is better than by thermal spraying, and the cold adhesion is the best way to prepare the wear resistant coating.
Study of Mastic-Aggregate Interfacial Adhesion in Cement Emulsified Asphalt Mixture Based on the Discrete Element Method (DEM)
Authors: Wang Zhen Jun , Wang Rui , Wang Qiong , Yang Guang Ying
Published: December 2011

Cement emulsified asphalt mixture is a kind of composite materials, which is comprised of organic and inorganic materials, such as emulsified asphalt and cement, and has both advantages of cement concrete and asphalt concrete. Aiming at the problems of cement emulsified asphalt mixture that adhesion decline and road performance down in the using of process, the Discrete Element Method (DEM) was used to simulate two different kinds of aggregate used in the mixture. Through comparing the splitting strength, stress-strain curve, fracture development situation, and so on, suitable aggregate type, limestone aggregate, was obtained, which had higher adhesion property with cement emulsified asphalt binders.
Investigation of Microstructure and Machinable Mechanism of the B4C/BN Composites Fabricated by Hot-Pressing Process
Authors: Jiang Tao
Published: December 2011

The B4C/BN composites were fabricated by hot-pressing process. The B4C/BN composites included the B4C/BN microcomposites and the B4C/BN nanocomposites. The B4C/BN microcomposites were fabricated by hot-pressing process, and the B4C/BN nanocomposites were fabricated by chemical reaction and hot-pressing process. In this research, the phase composition, microstructure, machinability and machinable mechanism of the B4C/BN microcomposites and the B4C/BN nanocomposites were investigated. The microstructure of the B4C/BN composites was investigated by SEM and TEM. The SEM micrographs showed that the B4C/BN microcomposites and the B4C/BN nanocomposites exhibited the homogenous and compact microstructure, and the h-BN particles were homogenously distributed in the B4C matrix. The TEM micrographs of the B4C/BN composites showed that there existed the weak interface between B4C matrix grains and h-BN particles as well as the microcracks within the laminate structured h-BN particles. The machinability of the B4C/BN microcomposites and the B4C/BN nanocomposites increased gradually with the increase of h-BN content. The drilling rates and materials removal rates of the B4C/BN composites increased gradually with the increase of h-BN content. The surface roughness of drilled specimens of the B4C/BN composites decreased gradually with the increase of h-BN content. The relationship between the microstructure and machinable mechanism of the B4C/BN composites was analyzed and discussed. The phase composition and microstructure of drilled debris of drilled specimens of the B4C/BN composites were investigated by XRD and TEM. The microstructure of drilled surface of drilled specimens of the B4C/BN composites was observed and analyzed by SEM.
New Reactive Compatibilizer B Preparation and its Application in Polystyrene Ether/Nylon 66 Alloy
Authors: Zhang Ya Tong , Li Ying , Li Li , Qu Xiong Wei
Published: December 2011

A new type compatibilizer-boric acid ester with carboxylic acid functional groups (refered as B) was synthesized and used in PPO/PA66 alloys. The PPO/PA66 alloys were produced by melting blending. The micromorphological and mechanical properties of PPO/PA66 blends with different contents of the compatibilizer were studied by transmission electron microscope (TEM), scanning electron microscope (SEM) and mechanical test. The effects of the compatibilizer B on the mechanical property and morphology of PPO/PA alloy were discussed. The results showed that, the compatibilizer B can also improve the mechanical property, besides showing good effect on the compatibility improvement for PPO/PA blends; it (B) acts as a compatibilizer for the blends by forming interim layer with dispersed phase PPO and continuous phase PA. The compatibilization of PPO and PA66 alloy was due to the chemical reaction between carboxyl group and amine group.
Synthesis and Antibacterial Activity of Acetyl Ferrocene Hydrazine Hydrazone and its Metal Complexes
Authors: Liu Yu Ting , Yang Zhi Peng , Yin Da Wei
Published: December 2011

Acetyl ferrocene hydrazine hydrazone and its novel metal complexes were synthesized. The structures were confirmed by elemental analysis, IR, molar conductance and thermo gravimetric analysis. The antibacterial activity was tests the result showed that the antibacterial activities of the complexes were significantly improved comparing with ligands.
Experimental Study on Seismic Behaviors of Structural Insulated Panel Shear Walls under Cyclic Loading
Authors: Yang Hui Feng , Liu Wei Qing , Lu Wei Dong , Yan Shu Ai
Published: December 2011

In this paper, a total of five structural insulated panel shear walls (SIPSW), in which with plywood facing and polystyrene foam board core, were tested under low cyclic horizontal loading. For the test specimens, different wall depth-width ratio and the opening sizes have been considered. The failure modes, failure mechanics, bearing capacity, lateral stiffness and ductility are discussed in detail. The test results showed that the hysteretic curve of SIPSW shows a reversed S-shape. Also the depth-to-width ratio and the opening dimensions of the shear walls have significant effects on load bearing capacity, ductility and elastic stiffness. What’s more, the performance of the SIPSW specimens was controlled by the fastener slip behavior of the SIP-to-spline connection, especially along the bottom spline. Finally, it is indicated that SIPSW have a good satisfaction upon seismic performance when used to timber structures.
Composite Polymer Materials and the Details Made of them for Cotton Machines and Mechanisms
Authors: Abed-Negmatova Nodira , Negmatov Jakhongir , Gulyamov Giyoz , Yuldashev Aziz , Eminov Sherzod , Bozorboev Shukhrat , Aripova Akida , Negmatov Shukurullo , Xojimuradov Dilshod
Published: December 2011

We have done experimental researches of study of impact of different fillers on physical, mechanical and tribological properties and found the optimal substance of fillers, which provides with best properties of polypropylene composite materials. We suggested the principle of construction of antifriction and antifriction-wear resistant polypropylene composite materials, which have high strength and tribological properties and used in cotton machines and mechanisms.
Developing of Effective Multipurpose Polymer-Bitumen Compositions
Authors: Negmatov Sayibjan , Rahmonov Bahrom , Sobirov Bakhodir , Abdullaev Akbar , Salimsakov Yuldosh , Negmatov Jakhongir , Negmatova Malika , Soliev Rustam , Mahkamov Dilshod
Published: December 2011

We researched and developed effective polymer bitumen composites for hermetic of deformities seals of concrete and asphalts roads, bridges, aerodrome and airfields used in hot climate conditions and high lands.
Effective Composite Chemical Reagents Based on Organic and Inorganic Ingredients for Drilling Fluids Used in the Process of Drilling Oil Wells
Authors: Negmatova Komila , Isakov Shodilbek , Kobilov Nodir , Negmatova Malika , Negmatov Jakhongir , Haydarov Jahongir , Sharifov Gulom , Rahimov Shuhrat
Published: December 2011

In this article are shown the results of researches of development of effective composite chemical reagents based on organic and inorganic ingredients for drilling fluids, used for the drilling of oil wells. In this article will give comparative properties of local drilling fluids compared with drilling fluids used in Russia, USA.
The Impact on Asynchronous Motor during High Voltage Power Quick Switching Process
Authors: Zhou Xue Song , Zhou Jin Cheng , Ma You Jie
Published: December 2011

High-voltage power switching process will produce over-voltage and impulse current, it will bring a range of complex power system problems and when cutting and closing the high voltage the asynchronous motor will also produce over-voltage and impulse current. They have some impacts on the high voltage asynchronous motor, may result in equipment damage. So how to control the production of the impulse current and reduce the size of the impulse current are the core issue of the switching device. This paper highlighted the impact of over-voltage and current effects on the asynchronous motor, finally, this paper refer to the harm of the impulse disturbance and provide some methods of reducing the impulse current, so that has certain significance to people of the actual power grid operation.
Research of Photovoltaic Grid System Voltage Stability Based on the Bifurcation Theory
Authors: Ma You Jie , Liao Cheng , Zhou Xue Song
Published: December 2011

In grid-connected photovoltaic system, the inverter, grid device, power electronic devices etc. They consume a large quantity of reactive power; mostly in distribution system, a perceptual load must also consume reactive power, these makes big interference interconnection of photovoltaic system after serious test the voltage stability. Therefore, carry on research of voltage stability in grid-connected photovoltaic system has important significance. With the voltage stability, voltage quality, analysis the possible influence of photovoltaic grid power system on power grid in safe and stable operation. Discuss probable bifurcation behavior in photovoltaic grid system. Introduce the basic concept of bifurcation, and then review the application of bifurcation theory in research of voltage stability from two aspects: static bifurcation and dynamic bifurcation. Finally take a look at bifurcation theory research of photovoltaic grid system voltage stability.
The Effect of Surface Coating on Thermal Manikin’s Stability
Authors: Yang Kai , Jiao Ming Li
Published: December 2011

Present thermal manikin is always enclosed by hard materials, and not covered with surface coating. So the surface condition of thermal manikin is very different with real body, which reduces thermal manikin’s stability. Therefore the research on thermal manikin’s surface coating and its effect on thermal manikin’s stability are necessary. In this paper, an appropriate material was selected to be thermal manikin’s surface coating and the satisfying result in improving the stability of thermal manikin was achieved. Firstly, five kinds of soft materials were selected to be candidate surface coating materials, which were EVA, HTV, TPU, medical used silicon rubber and cotton fabric. By lots of experiments and fuzzy mathematics theory, HTV was analyzed to have satisfying optimization performance than other materials and can be used as thermal manikin’s surface coating. Finally, to evaluate the effect of HTV surface coating on thermal manikin’s stability, comparative experiments were performed in climate chamber when thermal manikin covered with HTV surface coating and did not cover with HTV surface coating. Results show that HTV surface coating can obviously improve the stability of thermal manikin.