bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameterized Modeling and Analysis of Wind Turbine Blade Using VB and ANSYS
Authors: Zhang Jian Hua , Gao Dian Wei , Sun Ke , Liu Xin Sheng
Published: September 2013

It is very difficult to establish a model of wind turbine blade in finite element software directly because of complexity of the shape. To solve this problem, parameterized modeling and analysis program of wind turbine blade is developed applying of ANSYS secondary development technique based on VB6.0. Processes of establishing a finite element model, applying loads and extracting Post-processing data of wind turbine blade are described. A numeral example demonstrates the program is feasible and correct. The research work can help to speed up application of ANSYS secondary technique in design and analysis of wind turbine blade and provide references for parameterized modeling and analysis of similar engineering in the future.
A Parametric Experimental Study on the Heat Transfer Characteristics of Supercritical Kerosene in Active Cooling Channels of Scramjets
Authors: Wang Ning , Zhou Jin , Pan Yu , Wang Hui
Published: September 2013

Heat transfer characteristics of China RP-3 kerosene under supercritical state were experimentally investigated. Results showed that at sub-critical pressures, heat transfer deterioration happens, and the wall temperature rises from approximately 350°C to 750°C. This is thought to be resulted from film boiling when kerosene begins to transfer from liquid to gas. At supercritical pressures, heat transfer enhancement was observed. And it is mainly caused by the sharp increase of specific heat of kerosene when the wall temperature is approaching the critical temperature of kerosene. The heat transfer coefficient doesnt increase with velocity for kerosene, because the thermal properties and residence time of kerosene have changed when velocity is changed.
Wind Tunnel Test of Honeycomb in Improving Flow Quality
Authors: Li Chun Guang , Liu Yang , Cheung John.C.K.
Published: September 2013

The function of honeycomb with different length and width in improving flow quality were studied in the course of building a new small section open loop wind tunnel. Instantaneous velocities of turbulent flow in the tunnel were measured by cobra probe. The focus of this study was put on the effect of the honeycomb in attenuating the total turbulence intensity including the free-turbulence carried by the incoming flow and the turbulence generated by the square cells themselves. The change tendency of the mean wind velocity and the total turbulence characteristics in the decay area have been studied by varying the length to cell size ratio L/D, and ratio of distance between the square cells and the measuring position to cell size X/D.
Numerical Simulation of Bus Windshield Based on Heat Transfer with Impinging Jets
Authors: Li Hua , Zhang Ji Chun , Huang Ping Hui , Liu Ke Yan
Published: September 2013

The maximum vapor fraction in the air decreases with the temperature falling. For the air which has the high humidity, the redundant vapor will condense into fog or freeze into ice if the moist air attained a new saturation in a lower temperature. The buses running in the north cold areas usually face this problem in winter. According to the theory of jet impingement heat transfer, this thesis analyzed the influences of angle between the windshield and impinging jets and also the distance between vents and dashboard edge on defrosting by a simplified bus model. It also put forward some suggestions about defrosting on buses.
Study on the Temperature and Pressure of Oxygen Cylinder Attached Grease in Filling Process
Authors: Zhao Xu Sheng , Tao Gang , Ji Xu , Sun Xin Meng , Wang Zhong Yu
Published: September 2013

One of the reasons of chemical explosion is the grease enters the oxygen cylinder when fill and use it. The grease in the cylinder will be oxidized, which can elevate the temperature. The high temperature will decrease the ignition point of grease, and then the combustion and explosion will occur. To prevent such accidents in the cylinder filling process, the temperature of the gas in the cylinders must be strictly controlled. In this paper, the heat transfer of the cylinder wall is studied by the method of calculation and the pressure-temperature law of outer wall of the cylinder is obtained. Therefore, this paper provides a reference for chemical changes in the cylinder filling process. The grease should be degreased first before the cylinder filling process. The temperature of cylinder should always be ensured normal during the cylinder filling process.
Experimental Research on Damage to Fracture Conductivity Caused by Fracturing Fluid Residues
Authors: Wang Lei
Published: September 2013

Experimental research on damage to fracture conductivity caused by fracturing fluid residues has been done for the first time in China using FCES-100 (Fracture Conductivity Evaluation System). In the experiments, the degree of damage to conductivity caused by different types and concentrations of fracturing fluids were studied in the condition of different concentrations and types of proppants. The mechanism of damage to conductivity was studied and some methods on how to decrease the damage were brought forward, which is significant for the research on development of fracturing fluids and also for field treatments.
Flameless Venting Devices for Dust Explosions and Experimental Confirmation of their Efficiency
Authors: Peng Dian Hua , Wu Jian Xing
Published: September 2013

In a closed pulverized coal preparation system, a special device must be installed to vent flames and pressure during unexpected dust explosions. A vent flame arrestor is a key element in this device, which helps prevent a dangerous second explosion by venting flames. Traditional vent flame arrestors are designed with mounting metal fiber or rock fiber on both the sides and the top of the arrestor to cool dust flames and arrest burning dust during an explosion. This type of arrestor is widely used, but their application is still problematic, even for St1 dust at low reduced pressure (Pred). To solve these problems, we designed two types of flameless venting devices. The first is intended for St1 dust explosion venting at Pred 0.07 MPa, and was modified from an original device by adopting a labyrinth-like structure in the interior space to successively reduce the strength of the dust flame. The second is intended for St1 dust explosion venting at 0.07 < Pred 0.18 MPa, and was modified from the first type by adding a special suppressant in the interior space to make the dust flames cooler than the ignition point of the dust. Our experiments confirmed that our designs yield improved efficiency of flameless venting devices, leading to safer vent flame arrestors.
Characteristics Analysis of Hydraulic System for Screw Distributor of Asphalt Paver
Authors: Chen Long An , Mi Zhi Nan
Published: September 2013

The hydraulic system of screw distributor plays an important role in asphalt paver. It belongs to the speed-regulating system of pump controlled motor. The motor speed and direction of rotation can be controlled by variable delivery pump. Thus the transferring speed of bituminous mixture can be adjusted. The mathematical model of the system is presented, and dynamical characteristics are analyzed. Simulation results indicate that the system is suitable to screw distributor and has high operating efficiency. By changing the angle of swashplate, the rotating speed of motor can be adjusted proportionally. The undamped natural frequency of the system is lower for two reasons. One reason is only one line controlled by the trapped oil spring rate. The other reason is larger volume of pump.
Study on Self-Excited Vibration of Subsoiler-Soil System Based on Modal Analysis
Authors: Ma Xing , Qiu Li Chun
Published: September 2013

Modal analysis of chisel subsoiling shovel, arrow subsoiling shovel and double-wings subsoiling shovel were made, which was based on the analysis of the vibration characteristics of subsoiler-soil self-excited vibration system and finite element analysis software ANSYS13.0 was used. Natural frequency and the mode of vibration were determined. Then self-excited vibration conditions of the subsoiling system were studied. All these analysis results could provide theoretical references for the self-excited vibration subsoiling system optimization and design.
Determination of Load Capacity and Deformation for Modular Trailer
Authors: Huang Jian Hua , Gui Zheng
Published: September 2013

There are nearly infinite module combination and cargo support methods for modular trailer. By summarizing moments produced by every force and revised by chassis permitted moment the load capacity can be obtained with a giving support deviation. And by calculating unit force's virtual work, the deformation of the trailer chassis can be found in same support deviation. These algorithms are very brief and can be embedded in other software.
Design and Practice of FSAE Car Dynamic Data Acquisition System
Authors: Yu Shan Hu , Yao You Lin , Wang Yu Jian , Zhang Yun Hao , Li Jie , Yang Zhi Jian
Published: September 2013

According to the requirement of Formula Student China (FSC), combined with the actual of 2012 Guangzhou Auto S - Power team of South China University of Technology, a set of data acquisition system was designed and developed, and performance of the car chassis was analysed with data acquisition system, effective adjustment scheme is put forward. program was designed with LabVIEW software and NI cRIO 9076 data collector. This is experiment demonstrated that data acquisition system help designer to understand the quantitative value of the car performance in the process of the car testing, and help us to improve accuracy of the chassis adjustment, and also help us to improve work efficiency of commissioning phase.
Comparison and Analysis on Side Impact Sled Test of Child Restraint System
Authors: Liu Jun , Jia Lin Xi , Zhang Xue Rong , Zhou Hai Sen
Published: September 2013

Side impact is the second most frequent collision compared with frontal impact, accounting for about 30% of the total number of accidents. Indicating from the statistics, there is at least one child among 10 people died in the accident. It is noticed that children have a higher risk of suffering serious and fatal injuries in side impact than in other impact directions. Therefore, it is great important to protect children in side impact. However, procedure to test side impact performance of child restraint system (CRS) has not been agreed on yet in the world. This paper focuses on analyzing the difference between NHTSA and ISO 29062 side impact test procedures. It will help us perfect our automobile safety standards system and constitute our relevant laws as a valued reference through researching lateral impact dynamic test of CRS in other advanced countries.
Multi-Objective Structure Optimization Design of a Car Lower Control Arm
Authors: Wang Kai , Yang De Sheng , Ma Da Wei
Published: September 2013

A multi-objective structure optimization design of a car lower control arm was operated in order to improve both compliance and eigenfrequencies effectively. Based on SIMP (solid isotropic material penalization) method, compromise programming method was adopted to define multi-objective topology optimization. The topological structure of lower control arm was obtained through the optimization, and further, the new structure design. Results verified by FEA show that the new design can simultaneously satisfy the compliance and eigenfrequencies objective, and can meet yield stress requirements.
Numerical Optimization Research on Rear Characteristic Angles Based on MIRA Model for Aerodynamic Drag Reduction
Authors: Du Qian Qian , Hu Xing Jun , Li Qi Fei , Liu Yu Kun , Yang Bo
Published: September 2013

The rear characteristic angles of the passenger car in this study were defined as the inclination angle of rear window and the bottom inclination angle of aft based on the MIRA model. The numerical optimization method was used to analyze the influence of combined variation of two angles on the external flow field and the CD of the passenger car, in which we combined genetic algorithm with the CFD simulation to reduce aerodynamic drag by seeking the relatively optimal combination of two parameters above. The study reveals that when the combination of the inclination angle of rear window and bottom inclination angle of aft is 25oand 0.067o, the total pressure and streamline distribution in the flow fields of the MIRA model are improved greatly and the CD is reduced compared with the worst combination. This conclusion will have profound guiding significance in the aerodynamic design of the rear styling and shape of a car.
Transmission Ratio Research of Hydraulic Steering by-Wire System
Authors: Xu Huang , Song Yan Dong , Lu Zhi Xiong , Zhao Miao Miao
Published: September 2013

To test the hydraulic steering by-wire system whether can achieve the ideal steering characteristics, firstly take experimental tests of the full hydraulic steering system, getting the transmission ratio curve. Then the simulation for the hydraulic steering by-wire system by MATLAB showed that simulation results combined with the test curve, the hydraulic steering by-wire system satisfy the requirement of vehicle working.
Numerical Simulation and Wind Tunnel Experiment of the Aerodynamic Characteristics of a Formula Student Racing Car
Authors: Wang Guo Xin , Hu Yinuo , Xu Ting Ting , Li Ze Fei , Yang Bo
Published: September 2013

This research used CFD softwares to simulate the downforce generated with the airfoil set to different height, and also analyzed the difference on the downforce when the airfoil is set on the racing car. Several pairs of front wing (FW) and rear wing (RW) of different ground clearances were chosen during the wind tunnel experiment and the results were compared with those of the numerical simulations. With the results of the simulations as well as the experiment, an appropriate solution of the ground clearances of the FW and RW for different kinds of race is provided.
A Three-Dimensional Analysis Method for the Stability against Deep Sliding of Concrete Dam on Rock Foundation with Mud Layers
Authors: Liu Yun , Wu Yong Xin
Published: September 2013

With the limit equilibrium method for the rigid body, this paper deduces a three-dimensional analysis method for the stability against sliding of concrete dam on rock foundations with mud layers on the basis of the stability against sliding of wedge. The engineering practices show that it is economical and reasonable to apply the method given here to the analysis for the stability of concrete dam foundation with mud layers in the case that the dam axis being not parallel to the strike of mud layers.
The Standard Enthalpies of Formation of Energetic 4,5-dinitroimidazole derivatives: A Theoretical Study
Authors: Su Xin Fang , Wei Jing Hua , Wu Hai Ying
Published: September 2013

The standard enthalpies of formation for 7 derivatives of 4,5-dinitroimidazole in gas at 298 K were determined using isodesmic reactions at B3LYP/6-311G** and B3P86/6-311G** levels. The results indicate that the substitution of nitro group can increase the enthalpies of formation. The more the number of nitro group, the higher the enthalpies of formation. The standard enthalpies of formation of –NO2 and –CH3 substitution compounds on N atom are larger than corresponding ones on C atom.
Effects of Polymerization Parameters on Aqueous Deposited Copolymerization of Acrylonitrile and Itaconic Acid
Authors: Zhao Ya Qi , Feng Qiao , Du Ling Zhi
Published: September 2013

Pure powdery high molecular weight polyacrylonitrile (HMW-PAN) copolymers were firstly synthesized by aqueous deposited polymerization (ADP) technique employing 2,2'-Azobis (isobutyramidine) dihydrochloride (AIBA) as initiator and itaconic acid (IA) as comonomer. Various PAN polymers were obtained through changing different polymerization parameters. It is indicated that with the increase of total monomer concentration, initiator concentration, reaction temperature and reaction time, polymerization conversions of PAN copolymers all increased. While the molecular weights become greater with the increase of total monomer concentration. With the increase of initiator concentration and reaction temperature (under higher reaction temperature region), the molecular weights decreased. However, the molecular weights only had very little decrease at the end of long extension of reaction time.
The Mechanical Performance Degradation of Steels Effected by Corrosion
Authors: Lin Ming Qiang , Dai Feng Juan , Song Shi Yan
Published: September 2013

Corrosion of the steel affects seriously its mechanical performance. Based on the finite element methods, strength tensile properties of corroded steel were studied. Pit shapes and pit depths, pit locations, etc on the mechanical behavior of steel were studied mainly. Pit depth is major cause of produce rust steel mechanical performance degradation, because there is an obvious stress concentration phenomenon around pit, cause steel mechanics performance degraded significantly. Pit shapes and lengths may also be affected steel mechanical properties.
Tests on Effect of Gravity and Soil Density on Soil Cone Index
Authors: Shi Rui Yang , Li Jian Qiao , Zou Meng , He Ling , Fan Shi Chao , Yang Yan Jing
Published: September 2013

The cone index is one of the important indicators that can describe the comprehensive physical characteristics of lunar regolith. Its closely related to the sink and sideslip of lunar rover and also has widely used in prediction the trafficability, adhesion property, tractive performance of lunar rover. Based on component method, a kind of low gravity simulator, the tiltable test-bed has been built. This study has got the stable low gravity along axial direction and measured the penetration resistance characteristics of JLU-2 in different gravity through tests. The results shows that the gravity environment has an obvious impact on the cone index of lunar soil simulant, CI values reduce with the decreasing of gravity environment. Namely, in the low gravity condition, it shows weaker resistance ability for a foreign object to penetrate into. The result has important application value of prepare, optimize and risk assessment in walking mechanism of lunar rover and the sampling mechanism.
Mesoporous Silica Nanoparticles with Controllable Pore Size: Preparation and Drug Release
Authors: Wang Yang , Shan Yan , Chen Ke Zheng , Gao Lian
Published: September 2013

Mesoporous silica nanoparticles (MSNs), with controllable pore size at wider range (2-13 nm) and particle size about 100 nm, have been successfully prepared using different templates. N2 adsorptiondesorption isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the material. The results showed that the MSNs have high specific surface area, controllable pore-size and the pore volume, and uniform particle size. Their drug delivery properties were investigated. It was found that the amount of loading DOX is increased with surface area, and the multi-release experiments showed that they had a sustained-release property; MSNs with larger pore size had the larger amount of DOX.
Immobilization of β-Glucosidase on Modified Attapulgite
Authors: Jia Jianbo , Yang Yong
Published: September 2013

Attapulgite was modified with different methods and used as support to immobilize β-glucosidase. Effects of enzyme dosage, pH, temperature and time in immobilization on stabilities of immobilized β-glucosidase were investigated. The results showed that the optimum immobilization conditions of β-glucosidase on organic modification attapulgite were as follows: enzyme dosage 3600 U/g, temperature 50 °C, time 60 min and pH 5.0. The thermal and storage stabilities of immobilized β-glucosidase were improved significantly.
Failure Mechanisms of Nanoparticle Reinforced Metal Matrix Composite
Authors: Basak A. K. , Pramanik A. , Islam M. N.
Published: September 2013

The quest for the advanced functional material of superior functionality for advanced structure is being driven in various fronts of engineering materials. One of such front is metal matrix composite (MMC) which has already been proven as one of the most productive field in that respect. With the advance of technology, now it is possible to reinforce the MMCs with nanosized particles compared to conventional micron-sized ones. However, the addition of nanoparticle in the MMC to improve its mechanical properties is not unconditional. To achieve positive gain by adding nanoparticles in the MMCs, all the influencing factors should be taken into consideration. The present paper reviews the failure mechanisms of nanoparticles reinforced MMCs in light of its strengthening mechanisms.
Experimental Study of High-Temperature Resistant Cementing Materials in Geological Exploration Drilling Tools
Authors: Qin Zuo Guo , Shao Yong Jun
Published: September 2013

As the main carrier for the protective casing purposes, cementing material is an important part in cementing design. In order to obtain a high temperature and high pressure resistant cementing material with low elasticity, we investigated on the high-temperature resistant cementing material used in geological exploration drilling materials to seek better cementing material for fulfilling requirements of high-temperature, and to find the best formula using orthogonal test. With compositions of the material in different proportions, this article investigated performances of the cementing material, as thickening time, loss of water, and compressive strength. By comparison, high-temperature resistant cementing materials experimental technology program has been finally estimated, and the composition ratio of the components are determined.
Study on Strain Hardening Property and Bake Hardening Property of High Aluminum Dual Phase Steel
Authors: Hui Wang , Wu Qing Song , Lin Cheng Jiang
Published: September 2013

In this paper the strain hardening property and the bake hardening property of an original dual phase steel with high Aluminum had been studied. It can be disclosed that the dual phase steel has an excellent strain hardening property and bake hardening property with a strain hardening value of 125MPa and a bake hardening value of 60MPa as well as a total hardening value of 162MPa. The excellent properties of bake hardening and strain hardening will make some contribution to the application properties of the auto parts made by the new dual phase steel. Key Words:dual phase steel, strain hardening, bake hardening
Influence of Parameters on Microstructure of CePO4/ZrO2 Machinable Ceramics
Authors: Xu Jing , Wang Xin
Published: September 2013

Machinable ceramic was widely attended for it could extend application range of ceramic. As a kind of common ceramic, ZrO2 ceramic was used widely, but it was difficult to be machined. CePO4 powder was added into ZrO2 powder to prepare composite powder. In this paper, two dispersion methods were used to prepared composite powder: mechanical mixed method and flocculation of multiphase suspension were used. Composite powder that prepared by mechanical mixed method sintered at 1450°C, 1550°C and 1600°C respectively. SEM was used to study microstructure of samples. Result of SEM showed that microstructure of sample that sintered at 1550°C was better than others, and there was no obviously default was found in it. Effect of mechanical mixed method was better than flocculation of multiphase suspension in this paper.
Microwave Pre-Treatment Reduced the Browning of Peach Juice
Authors: Zhang Shao Ying , Wen Yan Juan
Published: September 2013

Peach samples were pre-treated with microwave at 90, 270, 450, 720 and 900 W for 30, 60, 90 and 120 s, and juice browning was investigated during processing and storage. Polyphenol oxidase activity and ammonia nitrogen content decreased with microwave power enhancement or treatment time. The acidity of the peach samples initially decreased and then increased with prolonged treatment. The peach samples treated at 270 W preserved more polyphenol. The peach samples pre-treated at 270 W for 90 s or 450 W for 30 s demonstrated a reduction in peach juice browning. After 45 d of storage at room temperature, the juice colour value of the peach samples treated at 270 W for 90 s or 450 W for 30 s was 143.3% or 131.8% higher than that of the control samples, respectively. Microwave pre-treatment is a reasonable processing method for the effective prevention of peach juice browning.
Mechanical and Morphology Properties of Polypropylene/
Nano-CaCO3
Composites
Authors: Shen Teng Fei , Wu Fa Chao
Published: September 2013

To provide polypropylene (PP) with better excellent mechanical properties, nanoCaCO3 particles are incorporated into PP matrix by melt blending in this work. To improve the mophology between PP and nanoCaCO3, maleic-anhydride grafted PP (PP-g-MAH) was added as a compatibiliser. The results showed that PP-g-MAH indeed enhanced the interfacial adhesion of PP /nanoCaCO3 composites, which is demonstrated by the measurement of scanning electron microscope (SEM). The results of tensile tests revealed that the inclusion of nanoCaCO3 slightly increased modulus and decreased tensile strength and significantly increased the elongation at break. At high fraction of nanoCaCO3, the elongation at break was declined. The nanosized feature, shape and dispersion conditions of nanoCaCO3, played important roles in determining the performances of PP/nanoCaCO3 composites.
Graphene Based Electrode Using in Rechargeable Lithium Ion Batteries
Authors: Gao Chun Xue , He Da Wei , Fu Ming , Wang Yong Sheng , He Jia Qi , Wang Hai Teng , Zhuo Zu Liang , Li Shu Lei
Published: September 2013

Graphene as high capacity anode materials for rechargeable lithium ion batteries (LIBs) have been studied extensively with the aim of enhancing lithium ion and electron transport, lowering the stress caused by their volume changes during the charge/discharge processes of electrodes in LIBs. As we know, graphite is a practical anode material used for LIBs, because of its capability for reversible lithium ion intercalation in the layered crystals, and the structural similarities of graphene to graphite may provide another type of intercalation anode compound. In this work, the anode electrodes of LIBs include graphene nanosheet (GNS) and graphene nanosheet + carbon nanotubes (GNS+CNT). GNS was prepared through the thermal exfoliation of oxided graphite (OGS), which was synthesized by a modified Hummers method. The specific capacity of GNS was found to be 280 mAh/g after 200 cycles at 1C, and this was increased up to 320 mAh/g by the incorporation of macromolecules of CNT to the GNS.
Study of Nanoparticle Iron-Nitride MRF and its Rheological Characteristic
Authors: Zhao Si Hai , Zhao Zhe Qian , Jiao Lin Yu , Hu Yu Wei , Dong Ji Shen , Gao Ji Ye
Published: September 2013

The gas-liquid reaction method was used to prepare the nanoparticle iron-nitride magneto-rheological fluid (MRF), the experiment study of magnetic characteristic and rheologic characteristic of the MRF has been done. The magnetic saturation of iron-nitride MRF prepared is higher than the pure iron MRF, and the sedimentation stability of the iron-nitride MRF is very good, the yield stress of iron-nitride magneto-rheological fluid prepared reached 26KPa at 0.8 Tesla additional magnetic density.
The Contrast Study of Microwave Heating and Traditional Heating Leaching Vanadium from Stone Coal with Sulfuric Acid Solution
Authors: Ma Hong Zhou , Wang Yao Ning , Lan Xin Zhe
Published: September 2013

The aim of this paper is to contrast the effect of the microwave heating and traditional heating leaching vanadium from stone coal with sulfuric acid solution, contrast the leaching rate of vanadium, kinetics of leaching vanadium and the phase change s of slag. The experiment results show that the leaching rate and leaching velocity of vanadium with microwave heating was higher greatly than traditional heating, the kinetics of leaching vanadium with two heating methods was similar and accords with unreacted core contraction model with have solid product layer model, the illite in the stone coal was decomposed with microwave heating, but the traditional heating could not decomposed.
Enhancement of Acid Stability of Alpha Amylase from Bacillus licheniformis by Error-Prone PCR
Authors: Xu Yan Jing , Liu Yi Han , Fan Shuai , Lu Fu Ping
Published: September 2013

Acid stability of Bacillus licheniformis alpha amylase (BLA) was improved by error-prone polymerase chain reaction. The mutated BLA gene was expressed in Escherichia coli. An acid stability double mutant (K344R/H405R in BLA) was isolated. Two single mutants K344R and H405R were obtained by the way of site-directed mutagenesis. The enzymes (BLA) of the three mutants were isolated and characterized. Kinetic studies showed that the kcat/Km values of the mutants K344R, H405R, and K344R/H405R under pH 4.5 were about 8-, 11.5-, and 17.7-times higher than that of the wild type enzyme. As revealed by the structure models of the wild-type and mutant enzymes, the amino acids substituted of R344 and R405 in the BLA contribute to its acid stability.
Research on Aerodynamic Impacts of Snow on Bridge Decks
Authors: Duan Qing Song , Ma Cun Ming , Xie Bin
Published: September 2013

With the development of economy and technology, many long span bridges have been constructed. However, oversize thickness and long duration of snow on these long span bridges might lead to security issues. The computational fluid dynamics software FLUENT is employed to simulate the snow effect on the bridges. According to the two-phase fluid theory, the relationship between air phase and snow phase is one-way coupling. The corresponding changes of snow load on the bridge deck under the action of strong winds are studied in this paper and the comparative analysis about aerodynamic impacts before and after the snow are conducted as well. According to the results, the snow has notable influence on the aerodynamic characteristics of bridge decks. Keywords: computational fluid dynamics; two-phase fluid theory; snow load; aerodynamics;
Preparation of Tungsten Oxide Nanoplate Thin Film and its Gas Sensing Properties
Authors: Chen Qiu Lan , Lai Xi , Yan Meng Long , Tang Guan Rong , Luo Jian Yi , Chen Jian , Xie Wei Guang
Published: September 2013

Tungsten oxide is a kind of multifunctional materials with excellent properties for gas sensing, electrochromic and photocatalytic applications. In this study, Tungsten oxide nanoplate thin film was prepared by hydrothermal methods. The as-prepared thin film is composed of tungsten trioxide hydrate nanoplates, which are randomly orientate on the surface. The as-grown nanoplate thin film shows good sensitivity to H2 gas. Dehydration and phase transition to γ-phase tungsten trioxide were found after annealing, and the sensitivity as well as the response time to H2 were improved. We found that the nanoplate in the annealing sample bursts, which raises the surface-to-volume ratio for better hydrogen diffusion and reaction. The sensing mechanism was discussed. The findings provide a way to control the structure and surface morphology for improving the H2 sensing properties of tungsten oxide.
Simulation of Polarization Effect in GaN/AlN Resonant Tunneling Diode
Authors: Tang Nai Yun
Published: September 2013

Influence of polarization effect on current across GaN/AlNresonant tunneling diode (RTD) is simulated by self-consistent calculations ofSchrödinger and Poisson equations. When taking into account polarization chargesat the heterointerface, the band diagram and electronic properties of RTD areobviously changed. As a result, the current-voltage characteristics showsasymmetrical phenomenon. As the polarization effect is enhanced, the resonancepeak is shifted accordingly and even disappears.
Research on the Simulation of Friction Material Surface Topography
Authors: Ma Run Bo , Xu Shi Meng , Du Jian Hua
Published: September 2013

Through analysis and research on the surface topography of reinforced copper matrix composite materials, taking advantage of fractal statistical method to discuss distribution law about characteristics parameter which symbolizes the asperity, combining Monte-Carlo method with fractal theory to set up mathematics model of characteristics parameter which symbolizes size of asperity , talking about the construction of iterated function system in fractal interpolated theory, a easy realizable friction materials surface topography simulation algorithm was put forward.
Lamination of Green Ceramic Tapes with Adhesive at Ambient Temperature
Authors: Wang Shao Hong , Zhou Dan , Hou Zhao Xia , Wang Mei Han , Hu Xiao Dan , Liu Xiao Dong
Published: September 2013

In this paper, green ceramic tapes are joined together by adhesive based lamination technique. The effects of adhesive concentration, pressure on the lamination and sintering temperature on the laminate are mainly discussed. The parameters are also optimized. It was shown that the effect of adhesive concentration and pressure on the lamination is obvious and the effect of sintering temperature is not big. 10 layers of cordierite tapes can be laminated under 2MPa with a dwell time of 3min with PVA by adhesive based lamination. The adhesive based lamination can be used to be an alternative of thermo-compressive lamination.
Vertical Floating Zone Crystal Growth of R2PdSi3 Intermetallic Compounds (R=Pr and Nd)
Authors: Xu Yi Ku , Liu Lin , Löser Wolfgang , Frontzek Matthias
Published: September 2013

The class ofR2PdSi3single crystals (R= rare earth element) with hexagonal AlB2-type crystallographic structure reveals the systematic dependence of anisotropic magnetic properties governed by the interplay of crystal-electric field effects and magnetic two-ion interactions. Here we compare the floating zone (FZ) crystal growth with radiation heating of compounds Pr2PdSi3and Nd2PdSi3. The congruent melting behavior enabled moderate growth velocities of 3 to 5 mmh-1. The preferred growth directions are close to the basal plane of the hexagonal unit cell. The composition of the crystals, is slightly Pd-depleted with respect to the nominal composition 16.7 at.% Pd. The Pr2PdSi3compound exhibit antiferromagnetic order below the Néel temperatures TN: 2.17 K and Nd2PdSi3compound order ferromagnetically below the Curie temperatureTC= 15.1 K.
Numerical Simulation on Two Phase Combustion Characteristic in Solid Rocket Ramjet Afterburning Chamber
Authors: Zhang Nai Fei , Xu Yi Hua , Zeng Zhuo Xiong , Xu Ben En
Published: September 2013

Numerical simulation on two-phase combustion characteristic in afterburning chamber of solid rocket ramjet was carried out by applying particle trajectory model. It was analyzed that the nozzle number of secondary combustion chamber, inlet angle of air and particles diameter impact on efficiency of combustion. Results show that the combustion efficiency in the afterburning chamber is highest, achieving 99.6% when the angle between both air inlets is 180°, particle diameter is 15μm, and 5-hole nozzle is used. By contrary, when the angle between both air inlets is 90°, particle diameter is 5μm, and 5-hole nozzle is used, the afterburning chamber has a lowest combustion efficiency of 70.3%.
The W Loading Effect on SCR deNOx Performance for V-W-Mo/TiO2 Catalyst
Authors: Peng Ji Wei , Luan Tao , Gao Yan
Published: September 2013

The SCR catalysts were produced with V2O5, WO3, MoO3and anatase type TiO2. The catalyst samples were ground and sieved for 0.3~0.6mm.The NO catalytic efficiency, selectivity against N2O of the catalysts were investigated on a fixed bed reactor under simulated exhaust gas with a typical gas composition. The addition of W enhanced the catalytic efficiency of V(1)-W(x)-Mo (4.5)/TiO2catalysts at high temperature region, while lessened that at low temperature. Increasing the loading of W from 1.5% w/w to 4.5% w/w advanced the maximum catalytic efficiency from 88% to 99% and enlarged the temperature window of the catalyst. The presence of W promoted the N2O generation. The V(1)-W(4.5)-Mo (4.5)/TiO2catalyst showed higher catalytic selectivity for NO compared to the catalysts loading W.
Investigation Stress-Strain Behaviors of Glass/Polymer Composites
Authors: Ye Jun Jie , Li Da Peng , Han Xiao Hui , Chen Bao Jia
Published: September 2013

In this paper, a micromechanical model based on Generalized Method of Cells(GMC) for predicting stress-strain behaviors of polymer-matrix composites is presented. Improved Bodner-Partom viscoplastic model is incorporated into GMC to describe nonlinear mechanical behavior of composites. On this basis, strain rate and fiber volume fraction(FVF) influence on nonlinear behaviors of composites are discussed. The results show that strain rate influences on stress-strain behaviors of composites in inelastic region can be clearly discerned. Moreover, FVF tends to clearly increase stiffness behaviors of polymer-composites.
Spectroscopic Investigation of V3+:YAG Crystal
Authors: Ma Jian
Published: September 2013

V3+ions doped YAG crystals were grown using the Czochralski method in a highly pure argon atmosphere. The transmission spectrum of trivalent vanadium in YAG crystal has been measured at room temperature. Eight bands were observed in which two bands centered at 690nm (14493cm-1) and 1490nm (6711cm-1) are reported for the first time. By using the crystal-field theory and introducing the average covalent factor model, we also presented the theoretical calculations of the energy level splitting of tetrahedrally coordinated V3+impurity systems in YAG crystal. These calculation results are in good agreement with the optical experiment data.
Tunneling Recombination Mechanism in n-Type a-Si:H Steady State Regime
Authors: Souad Tobbeche , Merazga Amar
Published: September 2013

In this paper we developed a recombination model for the steady state photoconductivity (SSP) with the assumption that the correlated dangling bond states (DB) act as the essential recombination centres and the electron recombination proceeds by tunneling from the conduction band tail states (TS) for n-type a-Si:H. The modeled temperature dependence of the SSP presents the main measured features, particularly the small activation energy and the thermal quenching.
The Attenuation Trend of the Propeller Noise
Authors: Xiao Chang Run , Liu Rui Jie , Ye Jin Ming
Published: September 2013

The blade frequency noise of non-cavitation propellers in an non-uniform flow is analyzed in time domain. The unsteady loading (dipole source) on the blade surface is calculated by a potential-based panel method. Through calculation and comparison, the noise attenuation trend of propeller is discussed. The noise decays more quickly in the near field than in the far field. The Attenuation Trend of the Propeller Noise
Analysis of Nano Luminescent Materials and Devices Based on Paper Intelligence
Authors: Huang Xiao Li , Zheng Jia , Wang Ying , Kong Xiang Rui
Published: September 2013

Based on papers collected by Conference Proceedings Citation Index – Science (CPCI-S) database from 1989-2011, this paper investigates and analysis the innovation status and development trends of Nano luminescent materials and devices through the quantitative analysis of paper distribution in the year, the hot R&D field, affiliations and the conference sources in hope of providing an objective statistic reference for future academic researches and innovation development．
The Effect of Proton Implantation on Photoluminescence from Ensembles of InAs Quantum Dots Embedded in GaAs
Authors: Tang N.Y. , Cui Hao Yang
Published: September 2013

The light-emission efficiency of InAs/GaAs quantum dots (QDs) affected by proton implantation and subsequent annealing is investigated. The photoluminesce (PL) intensity is determined by the carrier capture time and non-radiative center (NRC) lifetime. The intermixing-induced carrier capture enhancement and the implantation-induced NRC generation mutually compete, so there exists a critical implantation dose (). When is less than , the intermixing is the main effect and the PL intensity increases with . On the other hand, when is larger than , the implantation damage is so large that the intensity decreases with the dose. The higher the annealing temperature is, the larger becomes.
Growth of n-Doped and p-Doped GaAs Nanowires by Au-Assisted Metalorganic Chemical Vapor Deposition: Effect of Dopants Flux Rates
Authors: Zhang Peng , Liu Yan , Guo Jing Wei , Zhang Xiao Pin
Published: September 2013

N-doped and p-doped GaAs nanowires (NWs) are grown on GaAs (111) B substrate using vapor-liquid-solid (VLS) mechanism via a metalorganic chemical vapor deposition (MOCVD) system. It is found that for n-type doped NWs growth rate is proportional the flux rates of dopant and the structure is pure zinc blende without any faults. For p-type doped NWs with large flux rates, there is a critical length, beyond which NWs will be kinked.
Effect of Aging Treatments on Microstructure and Exfoliation Corrosion Behavior of Spray Forming 7075 Alloy
Authors: Su Rui Ming , Qu Ying Dong , Li Rong De , Xie Qi Ming , Wu Yu Sheng
Published: September 2013

Mechanical properties, microstructure and exfoliation corrosion (EXCO) behavior of spraying forming 7075 alloy underwent retrogression and re-aging (RRA) were studied by tensile test, transmission electron microscopy and EXCO test, and compared with those of T6 peak aging and T73 overaging treatments. The results show that after T6 treatment, abundance transgranular dispersive η phases make tensile strength of the alloy reach 760MPa, elongation and EXCO rating are only 4.8% and ED respectively by dint of continuous η phases at grain boundaries and narrow precipitate free zones (PFZ). After T73 treatment, interrupted η phases at grain boundaries and wide PFZ can improve elongation and EXCO resistance, but depressed volume fraction of coarsening transgranular η phases reduce tensile strength to 676MPa. After RRA treatment (120°C/24h + 200°C/10min + 120°C/24h), abundance transgranular dispersive η phases separate out again, η phases at grain boundaries interrupt, and PFZ widen slightly. Tensile strength, elongation and EXCO rating of alloy are 758MPa, 8.4% and EA respectively.
Vacuum Synthesis of Nanocrystalline TiC at a Low Carbothermal Reduction Temperature
Authors: Xiang D.P. , Li C. , Liu C.J. , Ding L.
Published: September 2013

Ultrafine TiC powders with a grain size of about 25 nm were synthesized from nanoanatase TiO2/carbon black mixtures by mechanical activation-assisted vacuum carbothermal reduction (MCR) reaction. The effects of mechanical activation and carbon sources on TiO2 carbothermal reduction (CR) were also investigated. Results indicated that the CR of nanoTiO2 was enhanced after pre-milling of the starting powders. The synthesis temperature and holding time of TiC decreased from 1500 °C to 1300 °C and from 4 h to 2 h, respectively. However, phase evolution analysis of the reaction showed that mechanical activation did not alter the phase evolution sequences of the TiO2 CR. In addition, the relative weight loss of powders in increasing temperatures indicated that nanoTiO2 MCR can be divided into three stages, in which the reaction rate of the second stage is found to be the fastest. The study on the effect of different carbon sources on the MCR of nanoTiO2 showed that the use of nanocarbon black as carbon source can cause MCR to react more thoroughly than the use of graphite and active carbon.
Preparation and Properties of poly (n-butyl acrylate)/ poly (methyl methacrylate-co-styrene) Emulsion Polymer with Pentaerythritol Triacrylate as a Cross-Linking Agent
Authors: Jiao Li Yong , Yuan Gang , Qi Yun Peng , Li Lin Lin
Published: September 2013

A series of cross-linking core-shell structured poly (n-butyl acrylate) /poly (methyl methacrylate-co-styrene) emulsion polymer were prepared by semi-batch seeded emulsion polymerization with pentaerythritol triacrylate (PETA) as a cross-linking agent. The emulsion polymers were characterized by Fourier transform infrared spectra (FTIR) and transmission electron microscope (TEM), respectively. The influences of cross-linking agent content on the water resistance and mechanical properties of the emulsion films were investigated. The films prepared by the emulsion polymer with the cross-linking agent exhibited excellent water resistance, and mechanical properties (tensile strength and flexility), resulting from the cross-linking structure of shell segments compared with that prepared without cross-linking agent. The film of the emulsion polymer with 1.0wt% cross-linking agent exhibited better comprehensive performance.
The Influence of High Magnetic Field on the Stability of CryoECAPed 1050 Alloy
Authors: Cao Yi Heng , He Li Zi , Liu Xiao Tao , Zhang Hai Tao , Wang Ping , Guo Ya Ping , Cui Jian Zhong
Published: September 2013

The evolutions of mechanical properties and microstructure of cryoECAPed 1050 alloy annealed at various temperatures from 150°C to 400°C for 1h with and without high magnetic field (HMF) were investigated by hardness test and electron back scattering diffraction pattern (EBSD) analysis. The abnormal grain growth happens in sample annealing at 400°C without a field. With the application of high magnetic field, the formation of the HABs is suppressed, the grain size distribution is homogeneous and no abnormal grain growth occurs.
Phase Evolutions in the Metallic Precursors of the Ternary Copper-Indium-Gallium System
Authors: Wang Jian , Zhu Jie
Published: September 2013

Two types of metallic precursors used for the growth of Cu (In,Ga)Se2were deposited from a single CuInGa ternary target and binary alloy CuGa and CuIn targets, respectively. Phase evolutions in the precursors of the ternary copper-indium-gallium system were investigated over the temperature range from room temperature to 500°C. Grazing incidence X-ray diffraction (GIXRD) and scanning electron microscopy (SEM) were applied to characterize evolution of phases and surface morphology in the precursor layers. With annealing temperatures increased, phase evolutions of Cu9Ga4, Cu11In9, Cu16In9and CuIn were observed. Surface morphology of the two types of precursors changed significantly, which could support the phase evolutions in the ternary Cu-In-Ga system for reactive annealing processes. The existence of the final Cu11In9phase, which is the most favorable intermetallic phase for the formation of CuInSe2and Cu (In,Ga)Se2thin films, may be transformed by a speculated peritectoid reaction of In and Cu16In9to Cu11In9under In-rich condition.
Effect of NO2--N Concentration on Denitrifying Phosphorus Accumulating of Nitrosation Denitrifying Phosphorus Accumulating Organisms
Authors: Zhang Li Cheng , Wu Chun Rong , Liu Qiang , Yu Yang , Liu Xiao Wei
Published: September 2013

Separating NDPAOs from the continuous flow double sludge nitrosation denitrifying phosphorus removal system, purifying and preliminary identifying them, discussing the effect of NO2--N concentration on the performance of denitrifying phosphorus accumulating of NDPAOs by the way of pure training. The results showed that the identified organism Veillonella could treat NO2--N as electronic receptors when the NO2--N concentration was 60mg/L; when the NO2--N concentration raised to 65mg/L, phosphorus accumulating was not normal; the denitrifying was abnormal while the NO2--N concentration further raised to 70mg/L; when the NO2--N concentration was 80mg/L, characteristics of phosphorus uptake and denitrifying had suffered serious inhibition.
Dioctyl Phthalate Esters Wastewater Treatment by Fenton Reagent / Fly Ash Combined Process
Authors: Wang Li Ping , Li Xin Ying , Li Xiang Mei
Published: September 2013

Used Fenton reagent and fly ash combined process to treat dioctyl phthalate (DOP) simulated wastewater. Influences of pH, concentration of H2O2, Fe2+ concentration, fly ash dosage and other factors effect of COD were studied. The results showed that, under the synergies of the fly ash, Fenton reagent on the COD removal efficiency was better than Fenton reagent used alone. When the pH was 5, H2O2 concentration was 1.2 g/L, Fe2+ concentration was 1.0g/L, fly ash dosage was 4 g, and COD removal efficiency reached 83.21%.