bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication and Photocatalytic Activity of ZnO-TiO2 Nanofibers
Authors: Ju Jian Feng , Wu Dong Hui , Shi Yu Jun
Published: July 2011

PVP/ZnO-TiO2 composite nanofibers were prepared by Sol-gel processing followed by electrospinning technique using Ti(OC4H9)4 and polyvinglpyrrolidone ( PVP) as starting materials. ZnO-TiO2 nanofibers of 100–200 nm diameter were obtained by high temperature calcinations of the inorganic organic PVP/ZnO-TiO2 composite fibers.The materials were characterized by differential scanning calorimetry thermogravimetric analysis (DSC- TGA) , Fourier transform infrared (FT-IR),and scanning electron microscopy (SEM). The process of the photocatalytic degradation of methylene blue using ZnO-TiO2 nanofiber as catalyst was investigated.The results show that the ZnO-TiO2 nanofiber dopped 3% ZnO has better photocatalytic activity for methylene blue degradation, the degradation rate of methylene blue solution reached 99% under sunshine for 6 h., and it’s still 95% after eight times reuse.
Investigations on Properties of PE/PET Bicomponent Spunbonded Nonwovens
Authors: Chen Jin Jing , Guo Zheng , Chen Jin Liang , You Jin Zhang
Published: July 2011

The properties of PE/PET bicomponent spunbonded nonwovens with various areal density in certain processes were tested and analyzed. The areal density of samples can be changed by adjusting the speed of net belt. The evacuated materials which are discussed in this paper are PE/PET bicomponent spunbonded nonwovens whose areal density are 15 g/m2, 20 g/m2, 30 g/m2, 40 g/m2, 50 g/m2, 60 g/m2, 70 g/m2and 82 g/m2. The tensile strength, evenness and flexibility of the samples were measured. Also, the flexibility of PET spunbonded nonwoven were compared with the PE/PET bicomponent spunbonded nonwoven. The conclusion is that the strength, unevenness increase when the areal density increases, but the flexibility decreases. the flexibility of PE/PET nonwoven is superior to PET nonwoven, especially low areal density.
Numerical Simulation of Fracture Process of Three-Point Bending Beam of Concrete Based on Modified Mazars Model
Authors: Deng Ai Min , Gou Lian Meng , Xu Dao Yuan
Published: July 2011

Taking into account the initial damage and the accumulation of damage of concrete, Mazars damage model was modified. Based on the modified Mazars damage model, combined with finite element software ANSYS, the fracture failure process of the three-point bending notched beam of concrete was simulated. The initiation load Pini and maximum load Pmax of the three-point bending beam were determined with the damage criterion, and the full relation curve of the load P versus the loading point displacement Δ of the fracture failure process of the three-point bending beam was obtained. The results show that the method of numerical simulation of concrete fracture failure process is feasible, and based on the initiation load of the crack determined by numerical simulation, the initiation toughness of the beam can be easily calculated, and the problem of calculation of the initiation toughness caused by the initiation load can not be accurately determined in the actual experiment is resolved.
Analysis of a New Magnetic Bearing for Magnetic Levitation Stages
Authors: Zhu Yu , Liu Yu , Zhang Ming
Published: July 2011

This paper proposed a new configuration of magnetic bearings used in magnetic levitation stages. The equivalent current sheet model is introduced to calculate the levitation force of the proposed magnetic bearing, and the experiment result validates the correctness of the calculation method. The relationships of structural parameters to the levitation force and axial stiffness are studied, which prove that the new magnetic bearing has larger levitation force with lower axial stiffness over the working stroke and could be applied in ultra-precision magnetic levitation stages.
Grinding Wheel Carriage Mode Analysis of Vertical Glass Edging Machine
Authors: Xu Hong Hai , Zheng Xiao Li
Published: July 2011

The finite element model of grinding wheel carriage on glass edging machine was established, some key mechanical joints such as ball lead screw pair, linear rolling guide pair and lead screw bearing were simulated by combin14 spring-damp unit. The mode analysis was finished by ANSYS software, the frontal 4 modes and natural frequencies indicated that the weak part of grinding wheel carriage vibration was lead screw and assembly board of sliding block. The natural frequency and dynamic behavior of grinding wheel carriage will be improved by increasing diameter of lead screw and thickness of assembly board of sliding block, preloading lead screw bearing and ball lead screw pair, using middle or heavy preload linear rolling guide. The research result is very important for the design of large scale vertical glass edging machine.
The Effects of Rolling and Annealing on the High Speed Impact Deformation Behavior of Mg-3%Li-1%Nd Alloy
Authors: Liu Teng , Sha Gui Ying , Wang He Nan , Wang Xiao Lei , Yu Tao , Zhu Yu Hong
Published: July 2011

In this paper, the impact deformation behavior of the as-rolled and annealed Mg-3%Li-1%Nd alloy was investigated by using the Hopkinson compressive bar. The effects of rolling and annealing on the high speed impact deformation behavior were analyzed. The relationship between microstructure evolution and impact fracture mechanism was discussed.
A Modified Implicit Iterative Difference Algorithm for Stiff Chemical Kinetic Equations in Complex Combustion System
Authors: He Bo , Nie Wan Sheng , Feng Song Jiang , Li Guo Qiang
Published: July 2011

The splitting-operator method has been widely used in the numerical simulation of complex combustion system with its high computation efficiency. The main difficult encountered in the method is how to integrate the stiff chemical kinetics ordinary differential equation (ODE) efficiently and accurately in each grid node of flow field. Although several ODE software packages such as LSODE and VODE have very predominant performance in integrating stiff and non-stiff case, it couldn’t ensure the positivity of mass fraction in integrating stiff chemical kinetic ODE. A detail liquid rocket hypergolic bipropellant combination of Monomethylhydrazine (MMH)/Red Fuming Nitric Acid (RFNA) chemical mechanism consisting of 550 elementary reactions among 83 species was constituted basing on several relevant literatures firstly. And then a modified implicit iterative difference algorithm with variable time steps was developed to tackle the problem of mass fraction non-positive. The results from the integration of MMH /nitrogen tetroxide (NTO) chemical kinetic ODE indicate that the algorithm is always retain stability and positive value of mass fraction. The time step length would also be automatically adjusted at different chemical reaction time in the algorithm to keep its computational efficiency.
Calculation of Sound Radiation Power at Two Ends of Duct System
Authors: Feng Tao , Wang Jing , Liu Bin , Wu Xue , Li Nan
Published: July 2011

A method to calculate the radiation sound power from the sound source characteristic of the duct component is developed here; The relationship between the sound source characteristic and the acoustical boundary conditions of the duct ends is also researched by the experiment. Based on the two-port model, the sound source characteristic and the sound transfer matrix of the duct component can be obtained by the numerical or experimental methods. The calculation model to predict the radiation sound power at the end of the duct system is deduced from the sound source characteristic of the duct component. A simple experimental duct system to validate the calculation model is setup and the measurement and calculation results are compared here as well.
Stochastic Seepage Field Studies on Main Embankment of Yangtse Rive in Southern Jingzhou Zone of China
Authors: Wang Ya Jun , Zhang Wo Hua , Jin Wei Liang , Wu Chang Yu , Ren Da Chun
Published: July 2011

Implemented, based on practical engineering projects, is a statistical analysis of strata soil characteristics and geological columns sampled from the main embankment of Yangtse Rive in southern Jingzhou zone of China. Furthermore, it was verified under Kolomogorov-Smirnov theory that this assumption, namely, the statistical hypothesis of Gaussian probability distribution for random permeability tensors of soils to be submitted into the stochastic seepage field simulation would be accepted by the statistical testing. By the help of numerical analysis for stochastic seepage fields simulations using three dimensional finite element method as well as the rationality of simulated stochastic results, investigated were various statistical characteristics and random natures in random seepage fields of the main embankment of Yangtse Rive in southern Jingzhou zone of China. Meanwhile, the developed model was also examined through statistical testing. Especially, as a stochastic boundary condition, the random variation of upstream and downstream water level was taken into account of three-dimensional finite element model in practical analysis for the random seepage field simulations, by which, it has been realized deeply to describe disturbed effects of the boundary randomness due to variability of downstream and upstream water level over variabilities of simulated results presented by vector series of the random seepage field. Furthermore，the function of some safeguards to set up against the seepage problem，such as sheet-pile breakwater and catch-water，as the turbulence of complex boundary condition together with the effects of variability of soil permeability has been analyzed for description of influence of them on the hydraulic potential distributed in the random seepage field and the random evolution of stochastic seepage field under these comprehensive aspects has also been compared with the result obtained by determinate analysis for the corresponding steady seepage field problem. Philosophy deduced in this paper presents the necessity，feasibility and practicability of employing stochastic studies in seepage field problems. Meanwhile, sensitivities of random seepage field hydraulic gradient and downstream exit height were studied upon the variation of permeability and boundary conditions of the main embankment of Yangtse Rive in southern Jingzhou zone of China, by which, broadened is the research domain on seepage field evolution under uncertain numerical coverage.
Optimization Study on FRP Bolt-End Structure Parameters
Authors: Li Ying Ming
Published: July 2011

A new FRP bolt-end structure is presented and its structure characteristic is introduced in detail. The FRP bolt-end structure is optimized to determine the optimization structure by multi-target orthogonal experiment. The experiment results for the FRP bolt with the optimal structure shows that anti-drawing strength is more than 85kN, elongation percentage is more than 2.5% and bolt-end joint strength is more than 64kN. Its features can satisfy coal side support demand. So the new structure designed is reasonable.
Research on Parametric Design of Dedicated Computer
Authors: Li Shi Jie , Zhang Yan Rui , Shen Bing Bing , Bi Hai Xia
Published: July 2011

This paper is aimed at dedicated computer case. The solid models of dedicated computer were built by three-dimensional mechanical design software Pro/E; the parametric design of chassis components was carried out by the Pro/E secondary development tool Pro/Toolkit. A user application was created, including user-defined menus and user dialogs, so users can easily implement the models based on prototyping parts, and repeatedly modify them until satisfied, ultimately achieving the aim of improving design efficiency and saving design cost.
Based on Pro/E High Speed Milling of Thin-Walled Stents of Research
Authors: Wang Jian Qiang
Published: July 2011

Treating high speed milling theory as the guidance, this paper researched high speed milling process of bracket part based on Pro/E. Combined with the structural features of bracket part, three dimensional model is built by Pro/E and machining processes are worked out after analysis. Pro/E module was applied to fabricate tool paths. At last, finite element analysis method is introduced to study the processing deformation by Pro/E module, based on which measures to restrain processing deformations is advanced and processing sequences are optimized.
Research on Semi Physical Test System of PCU on Satellite
Authors: Sun Fang Fang , Ye Wei Dong , Liang Cai Ping
Published: July 2011

Power control unit (PCU) is an important component of space power system on satellite; it provides power supply to main bus and regulates output status of solar battery array in light district. So it is very important to test the performance of PCU before equipped in satellite. A semi physical test system for PCU is developed in this paper, some Agilent simulators are used to simulate working environment of PCU, and control software is programmed to control these simulator as well.
Mechanical System Dynamics Simulation of Crank Linkage Mechanism Based on Pro/E
Authors: Chang De Gong , Zhang Cun Sheng
Published: July 2011

The simulation analysis and research on crank linkage mechanism, which is the core part of the engine, are of important significance. Based on related theory, this paper introduces a simulation analysis method for crank linkage mechanism, which is using Pro/E. First of all, the 3D model of the mechanism is build; all the components are modeled and assembled. Then dynamic simulation for the crank linkage mechanism by using PRO/Mechanism is carried on, the result of characteristics of motion, stress, etc of the mechanism are shown. A more effective method about the simulation analysis of crank linkage mechanism is introduced in this paper.
Research on Speed Optimization of ESPCP System under Different Conditions Based on Neural Network
Authors: Luo Xuan , Wang Shi Jie , Lv Xiao Ren
Published: July 2011

The output speed of ESPCP system is caused by the coupling of multi-factors and it is a typical nonlinear optimization problem. The key factor affecting life of progressing cavity pumping system is the rotor speed. The associated constraints depends on the physical and chemical conditions including pressure difference between pressure difference of the pump two ends, oil viscosity, temperature and wear clearance, etc. Taken these parameters as original inputs, the nonlinear mapping relationship between rotor’s rotational speed and its affecting factors are determined by means of artificial neural network, and establish the output speed prediction model. After the simulation through samples study and by combining field data, it shows that the predicting results is basically in accordance with the observation data, and acquire satisfactory results. The research results show that the artificial neural network is an ideal method of ESPCP system speed optimization.
Fatigue Strength Analytical Study of Truck-Mounted Concrete Pump
Authors: Zhou Xin Xiang , Ren Nan Nan , Guo Shu Jun , Tang Yan Ling , Cui Yu , Tian Rong Liang
Published: July 2011

This paper is based on the design of the boom system of concrete pump car.fatigue strength of the boom system is analysed detailedly after completing a series of work, such as the boom system simulation, static strength , the stability analysis and structural optimization. Analysis shows that the easiest damaged location of the boom system is in the joint of the third boom, that is the place of the maximum stress in static analysis of the boom system.The safety coefficient is 1.393 after finishing fatigue analysis,and the numerical value is still bigger than specified safety coefficient, namely 1.3;the minimum life total amount (cycle) is 323500, which occurs in the third quarter boom, that is the place of the maximum stress in static strength analysis of the boom system; the fatigue strength of the boom system satisfy the requirement.These research work provide reliable reference for the design and improvement of the boom structure.
The Key Technology in Extrusion Tapping of Internal Thread
Authors: Li Yong Yi , Zhao Sheng Dun
Published: July 2011

Internal thread processing is an indispensable procedure in manufacture, its processing efficiency and quality become more and more important in modern manufacturing, especially in aerospace and automotive industry. Compared with the traditional process of cut tapping of internal thread, the process of extrusion tapping of internal thread possesses the following advantages: without chip, higher precision, better surface quality, better continuity of metallic, greater efficient, greater strength, longer tool life. This paper firstly introduces the current research status of extrusion tapping of internal thread, elaborates the principle and characteristic of extrusion tapping, analyzes the matal plastic flow law and thread forming characteristic during tapping, then generalizes the influencing law of the key technology on thread forming quality, such as extrusion tap type, lead hole diameter, tapping speed and friction. Furthermore, puts forward some improvement approach to reduce tapping torque and enhance forming quality of internal thread.
Preparation of TiO2 -Pillared Montmorillonite as Application to the Control of Blue Green Algae Growth in Eutrophic Water
Authors: Wang Hong Quan , Yan Chun Jie , Shu Guo Jing , Wang Duo , Zhang Hua Li , Chen Jie Yu
Published: July 2011

TiO2-pillared montmorillonite is successfully synthesized via sol-gel method, which is used to remove blue-green algae from water. The composite was characterized by X-ray diffraction and Scanning electron microscope. The analysis results shows that TiO2 has entered into the interlayer of montmorillonite and the d001 increases from 1.27639 nm to 1.64437 nm, and the surface charge of montmorillonite was recyanobacteriarkably raised from -41.5 mV (Fig. 1a) to +12.21 mV (Fig. 1b) mV at pH =6～8. The results of algae adsorption experiments displays the positive surface charge of modified montmorillonite was thus expected to induce the electrostatic neutralization between TiO2-pillared montmorillonite and Microcystis aeruginosa (CYANOBACTERIA) cells. When the cyanobacteria concentration is 12100 number/μL, chlorophyll content is 2.831883 mg/L, turbidity of the water is 44.2%, and TiO2-pillared montmorillonite is 0.5 g/L, the removing rate of chlorophyll and microcystis exceeds 90%, and the turbidity reduces from 44.2% to 19.1%.
Study on Thermal and Mechanical Properties of Natural Rubber Latex Modified by Trichlorobromomethane
Authors: Liao Xiao Xue , Liao Shuang Quan , Tang Bing , Luo Ming Chao , Zhao Yan Fang , Tan Hai Sheng
Published: July 2011

Natural rubber latex (NRL) modified by holgonated addition with trichlorobromomethane was prepared. The thermal properties of modified NRL were analyzed by thermogravimetric analysis (TG/DTG),differential scanning calorimetry (DSC) and dynamic mechanical analysis(DMA). The results showed that the thermal stability of modified NRL was lower than NRL and the thermal degradation of modified NRL was two-stage decomposition. With increasing of stress frequency, loss modulus and storage modulus of latex increased,while loss modulus and storage modulus of modified latex decreased,compared with NRL.
The Thermo-Mechanics Coupled Model of Polycrystalline Aggregates Based on Plastic Slip System in Crystals and their Interfaces
Authors: Chen Yun , Cui Jun Zhi , Nie Yu Feng , Guan Xiao Fei
Published: July 2011

This paper presents the thermal-mechanical coupled model of polycrystalline aggregates based on plastic slip theory inside crystals and on the interfaces of crystals. It involves the mechanics and heat conduction behaviors caused by both force loads and temperature changing in the polycrystalline aggregates. At first, the constitutive relationship inside single crystal, and the moment equations and energy equations are derived by means of rate-dependent plastic deformation theory and the formulas of elastic-plastic tangent modulus depended on temperature. And those on crystal interfaces are also given. Based on the ABAQUS software [1], the subroutines to calculate the tension, torsion and bending strength of polycrystalline copper are coded. The numerical simulation results show that breakages occurred more easily on the interfaces than other areas of the polycrystalline aggregates, especially for bending loading and torsion loading, and that’s consistent with results by molecular dynamics but their computing cost are less and less than MD simulation.
Preparation of Glass Ceramic Made from Fly Ash
Authors: Li Feng , Liu Xiang Dong
Published: July 2011

Using fly ash from the power plant and SiO2 as the main raw materials, glass-ceramic was prepared by melting method. By means of DSC, XRD and SEM, the crystallizations of CaO-Al2O3-SiO2 system glass-ceramic were studied. The results show that it is more and more difficult to crystallize as the content of SiO2 increases. When the content of SiO2 reaches to 41.5%, the crystal nucleus form in the form of shuttle shape, the crystals develop in the same direction for a certain zone. But the crystals develop into hexagon shape finally when they are heated for 1 h at 1100°Cafter nucleation at 780°C.The developed crystals are anorthite. The sizes of crystals are between 1- 1.5μm, their microhardness can reach HV804.
Relationship between Microstructures and Mechanical Properties of Ti-6Al-4V Alloy in Centrifugal Casting
Authors: Sui Yan Wei , Liu Ai Hui , Li Bang Sheng , Guo Jing Jie , Ju Wei Biao
Published: July 2011

Ti-6Al-4V alloy castings are made by means of induction melting technology. The relationships between grain size and tensile strength, yield strength, elongation percentage, investigated for Ti-6Al-4V alloy castings. The results show that the relationships between grain size, and tensile strength, yield strength, specific elongation, meet the Hall-Petch equation.
The Addition of a Nano-SiO2 on the Tribological Properties of PTFE Composite
Authors: Li Zhen Hua , Nie Wen Zhong
Published: July 2011

A kind of novel polytetrafluoroethylene (PTFE)-based composite filled with nano SiO2 are developed for sliding tribological applications. The specimens are fabricated with the compression moulding technique. And the mechanical and tribological properties of the composites are investigated. It is demonstrated that these properties are influenced by the content of fillers. The wear resistances of all the developed PTFE composites are much higher than that of pure PTFE with very low coefficients of friction. Among the developed composites, the mixture of PTFE + 30% nano SiO2 exhibits the best combination of properties. The improved tribological performance of nano-SiO2 filled PTFE composites can be attributed to the improved structural integrity of the composites.
The Research on Preparation and Application of a Silicon-Based Efficient Coagulant
Authors: Wang Jiao Jiao , Han Chun Ying , Zhang Li Dan
Published: July 2011

In this paper, research was focused on the synthesis of a new efficient coagulant, boron -containing poly-silicate zinc (PSZB).The effect of the SiO2 concentration, Zn/Si molar ratio, B/Si molar ratio, activation time on flocculation properties were examined in detail. And the optimal preparation conditions were determined. At the same time, the industrial wastewater and life wastewater were treated for the properties test. The experimental results showed that the flocculant had good stability and good effect. It is a kind of good performance of flocculants.
Yellow-Orange Upconversion Luminescence in NaYF4:Er3+, Yb3+ Phosphor Synthesized by Microwave Combustion Method
Authors: Sun Jia Yue , Cao Chun , Du Hai Yan
Published: July 2011

Erbium and ytterbium co-doped sodium yttrium fluoride (NaYF4:Er3+,Yb3+) was synthesized by combusting in home microwave oven directly. The structure and morphology of the sample was characterized by the X-ray diffraction (XRD) and scanning electron microscopy (SEM), and its upconversion luminescence properties were investigated in detail. Under 980nm semiconductor laser excitation, the color of upconversion luminescence of NaYF4:Er3+,Yb3+ was green and red, and its upconversion spectrum exhibited distinct emission peaks at 522, 543 and 652 nm, the emission appears yellow-orange to the naked eye. The law of luminescence intensity versus pump power proved that the intense green emission at 522 and 543 nm were from Er3+(2H11/2→4I15/2and4S3/2→4I15/2), and the weaker red emission at 652 nm was from Er3+(4F9/2→4I15/2), which belong to the two photon process.
Recycling of Pultrusion Production Waste into Innovative Concrete-Polymer Composite Solutions
Authors: Ribeiro Maria Cristina S. , Fiúza António , Castro Ana Cristina , Silva Francisco G. , Meixedo João Paulo , Dinis Maria Lurdes , Costa Carlos , Ferreira Frederico , Alvim Mário Rui
Published: July 2011

In this study, the added value resultant from the incorporation of pultrusion production waste into polymer based concretes was assessed. For this purpose, different types of thermoset composite scrap material, proceeding from GFRP pultrusion manufacturing process, were mechanical shredded and milled into a fibrous-powdered material. Resultant GFRP recyclates, with two different size gradings, were added to polyester based mortars as fine aggregate and filler replacements, at various load contents between 4% up to 12% in weight of total mass. Flexural and compressive loading capacities were evaluated and found better than those of unmodified polymer mortars. Obtained results highlight the high potential of recycled GFRP pultrusion waste materials as efficient and sustainable admixtures for concrete and mortar-polymer composites, constituting an emergent waste management solution.
The Mechanical and Tribological Properties of a Polyurethane Composite Filled with CNT
Authors: Li Zhen Hua
Published: July 2011

Effect of carbon nanotube(CNT) on structure, strength and tribological behavior of CNT/PU composites is studied in the filler range of 5 vol%. It is found that differences in filler content used to determine the type of structure evolved and patterns of variation of mechanical properties, friction and wear in response to increasing filler content. It is found that wear of low-filled CNT/PU composites is dominated by delamination mechanism and wear resistance changes correlate with structural transformations of the composites. The maximum increase in wear resistance of the PU composites is reached at 2 vol% filling.
Study on Cu-Based Catalysts for Synthesis of Indole
Authors: Xing Jun De , Jia Xiao Fei
Published: July 2011

A series of Cu-based catalysts for the synthesis of indole by the reaction of aniline and ethylene glycol were prepared and characterized by ICP-AES and XRD. The results indicated that the activity and stability of Cu/SiO2 catalyst was increased after adding Zn, Mn, Cr and Fe promoters. Mn promoter was favorable for the dispersion of Cu, Zn, Cr, Fe and enlarged the specific surface area of catalysts. It could be seen that the catalysts prepared by impregnation method had better stability and higher activity than the catalysts prepared by co-precipitation method. The catalysts with small grain size of Cu had higher activity than those with big grain size. Some catalysts showed excellent performances in this reaction.
Study on the Method of Adjustment Skateboard by Dial Indicator to Turning Cone
Authors: Huang Yong Rong
Published: July 2011

Dial indicator can be used to adjust skateboard to turning cone. First, the characteristics of traditional methods is introduced. Then, the step of skateboard rotation angle’s adjustment with dial indicator is analyzed. Before turning workpiece, the rotation angle of skateboard can be adjusted by the workpiece and taper plug, the rotation angle of skateboard also can be adjusted by tailstock sleeve and workpiece, and then the workpiece can be directly turned to the accuracy requirements dimensional. The rotation angle of skateboard is adjusted before processing, so it can avoid the repeated measurements and adjustment in the process, Therefore, this method can save processing time and improve the accuracy of the taper.
Oxidation Behavior of 2Cr12NiMoWV Steel in High-Temperature and High- Pressure Water Vapor
Authors: Wang Zhi Wu , Lei Yan , Wang Wei
Published: July 2011

Discrete mass gain method is adopted to determine the oxidation kinetic behaviors of 2Cr12NiMoWV steel in water vapor at 540°C and 17.5 MPa. Results indicate that the kinetic curve of the oxidation experiences a dramatic turning where the oxidation has lasted 20h, namely, the oxidation is faster than before the oxidation point of 20h, then oxidation rate is greatly reduced;, and after the oxidation has lasted for 300h, its reaction is inhibited to enter into a relatively stable period. The test analysis of oxide film under scanning electronic microscopy and electronic probe microanalyser shows that the formation process of the oxide film is as follows: needle-like oxide nuclei → short-strip oxide → fine equiaxed crystal grains → large equiaxed crystal grains or columnar crystal particles. The alloying elements involved in oxidation represent the law as follows: Fe, Mo and Si react with vapor at the initial stage of oxidation reaction to form Mo and Si-contained Fe-rich oxide. As the oxidation reaction proceeds, Cr gathered at the interface between the surface oxide film and the matrix, is internally oxidized. The Mo, Si and Cr in the surface oxide will be continuously volatilized with the occurrence of oxidation reaction.
Production of Size-Selected CuXSn1-X Nanoclusters
Authors: Ayesh Ahmad I. , Qamhieh Naser , Mahmoud Saleh Thaker , Alawadhi Hussain
Published: July 2011

Composites of copper–tin (CuxSn1-x) nanoclusters were synthesized using the magnetron dc sputtering gas–condensation technique. Targets with controlled ratios of Sn to Cu were used to produce CuxSn1-xwith different compositions. The effects on the nanocluster size and yield of the sputtering discharge power, inert gas flow rate, and aggregation length were investigated using a quadrupole mass filter. The sputtering discharge power was optimized to maximize the nanocluster yield. The results show that as the inert gas flow rate increases the nanocluster size increases and then decreases. These dependences could be understood in terms of the dominant nanocluster production mechanisms. This work demonstrates the ability of controlling the CuxSn1-xnanoclusters’ size and composition by optimizing the source operation conditions.
Study on Practical Calculation Equation of Concrete Strength Criterion under Tension Condition
Authors: Wang Xin Jian , Hao Shan Shan , Xi Xin , Hou Xing Min , Qu Shu Ying
Published: July 2011

In order to simplify the nonlinear analysis of reinforced concrete, a new study on concrete strength criterion under tension condition is made, and more simple and accurate practical calculation equations are put forward. The results from the equations agree well with the experimental data.
The Effect on Heterogeneous Nucleation of Solute Segregation
Authors: Yang Ai Min
Published: July 2011

The effect on heterogeneous nucleation of solute segregation was studied with segregating energy and segregating coefficient. The results showed that the segregating energyΔGγsegrof solute played a more vital role in the nucleating process, specially in the case that (1-k) is small. A critical criterion with the parameter was suggusted for estimating the nucleating abilitiy of the external particles in binary alloy, which had the vital theoretical or practical significance for choicing refiner.
Research Advance in Harmful Effects and Removal of Impurity Fe from Al and Al Alloys
Authors: Shen Hua , Yang Wei Dong , Liang He , Yao Guang Chun
Published: July 2011

The presence of Fe and harmful effects on mechanical properties of pure aluminum and aluminum alloys are introduced. Several purification methods are reviewed, but all of them are of definite limitations. It is effective that precipitation method, filtration method and centrifugal division method are integrated.
The Study on Pulping and Papermaking Performance of Banana Stem and Leaf
Authors: Qin Cheng Rong , Jiang Lei , Fu Xi Yao , Wang Qing , Yi Hong Gui
Published: July 2011

The chemical composition of various parts of banana stem and leaf were analysed. The soda cooking and kraft cooking process of banana stem were optimized. The bleaching performance of the banana stem pulp was discussed. The results showed that the banana stem and leaf kraft pulp were good fiber material for pulping and papermaking. The brightness of banana stem bleached pulp can reach above 80%ISO through ClO2 bleaching.
Research of Mechanical Properties of Ni-Ti-Nb Alloys on Low Temperature and Restriction Behavior
Authors: Zheng Li Xuan , Ma You Liang
Published: July 2011

Mechanical properties of Ni-Ti-Nb alloys taken by the different heat treatment processes and constraint reply conditions at low temperature had been tested respectively to analyzing the variation law. The results show that the mechanical properties of alloys under vacuum heat treatment is much better than that of alloys under cold-drawn and the general heat treatment. Additionally, there is not clear the yield plateau on the stress curve of constraint reply samples whoseσ0.2 is far greater than σs of unconstraint reply specimens, and the tensile strength is higher than the latter also.
Preparation of Novel Series of UV Dual Curable Polyurethane-Modified Epoxy Monoacrylates and their Films Properties
Authors: Liu Hong Bo , Lin Feng , Zhang Wu Ying , Xu Ling
Published: July 2011

A new series of radical-cationic UV dual curable polyurethane-modified epoxy monoacrylates (PMEMA) was prepared. Radical-cationic UV dual curable were prepared with photosensitive resin (epoxy monoacrylates (EMA) or PMEMA), reactive diluents, radical and cationic photoinitiators. UV dual cured films of those liquid compositions were obtained by using a high pressure mercury UV lamp. FTIR spectra identified the change of C=C and epoxy groups absorption peaks during the UV-curing process. The effect of different modified oligomers on the gel content, water absorption, mechanical and thermal properties of radical-cationic UV dual cured films was investigated. The characteristic C=C (1635cm-1, 810cm-1) and epoxide (910cm-1, 772cm-1) absorption speaks were no longer detectable after UV dual cured. The gel contents of all samples using PMEMA as oligomers were beyond 97.0% and their water absorption values were about 0.80%. With the length of flexible polyurethane chain segments increased, the Young’s modulus and breaking strength of UV dual cured films decreased gradually, except for the relative elongation. The volume shrinkage test indicated that the UV dual cured films exhibited lower internal stress and higher cohesive force than single radical UV cured films. The results of thermogravimetric analysis (TGA) for the UV dual cured films indicated good thermal stability with no appreciable weight loss until well above 250°C.
The Thermal and Di-Electric Properties of a Silicone-Based Thermal Pad
Authors: Jou Wern Shiarng , Hsu Chih Feng , Yeh Yu Kun
Published: July 2011

The properties of a silicone-based elastomeric thermal pad filled with inexpensive ceramic additives were studied in this research. The effects of the content, particle size and mixing ratio of two additives upon the thermal and di-electrical property of the thermal pad are investigated. The result shows that the higher the content, the higher the thermal and dielectric properties are. In addition, the thermal conductivity of two particles filled thermal pads are higher than that of a single particle filled thermal pad. The thermal conductivity of the two kind of particle sizes (14 and 2 um) of 60 % (vol.) SiC filled thermal pad is the highest (2.14 W/m·K).
The Controlled Synthesis of Single-Crystalline Cd(OH)2 Nanoparticles with Different Morphologies
Authors: Jia Zhi Yong
Published: July 2011

Single crystalline Cd(OH)2 low-dimensional nanostructures, such as nanowires, nanobelts, and nanorolls have been controlled synthesized through a convenient, low-temperature hydrothermal method. Moreover, the shape and diameter of 1D Cd(OH)2 nanostructures can be facilely controlled through adjusting the experiment factors. The influences of the ammonia concentration, temperature on the morphology of Cd(OH)2 are investigated, and a possible mechanism involved adjustable growth properties from kinetic growth stage to thermodynamic growth stage has been discussed. This work has also provided a general, simple, and effective method to control the shape of other transition-metal carbonate.
Precise-Micro PECM System and its Applications Combining Synchronizing Ultrasonical Vibration
Authors: Zhu Yong Wei , Miao Xing Lei , Zhang Chao Feng
Published: July 2011

The micro-PECM (Pulse Electrochemical Machining) combining synchronous ultrasonic vibration is proposed as a new technology for to solve the difficulty machining problems of conductive hard and tough materials. The feasibility of micro-PECM combining synchronous ultrasonic vibration is studied. The synchronous way is analyzed; the synchronous electrical circuit is designed and made. The synchronous electrochemical micro-machining system combining ultrasonical vibration are built and improved，which machining parameters can be adjusted in a wide ranges, and the synchronous target of the ultrasonical vibration with the voltage of micro-PECM can be realized. The micro-machining electrodes are manufactured in different sections and sizes by combined electrical discharge machining. The mechanism tests of micro-PECM are carried, which kentaniums （YBD151、YG8）and stainless steel are machined and the results are analyzed and discussed. Contrast with the single micro-USM, the micro-PECM combining ultrasonic vibration has high productivity, good machining accuracy and surface quality; furthermore, its cathode wastage is low. The micro-PECM combining synchronous ultrasonic vibration has the best machining precision and surface quality.
Evaluation of Permeability of Porous Concrete
Authors: Lian Chun Qi , Yan Zhu Ge , Beecham Simon
Published: July 2011

One of the most important characteristics of porous concrete is the ability to capture and transport water. The permeability of porous concrete is therefore needs to be evaluated. This paper will investigate various methods for testing the permeability of porous concrete and compares the different results from falling head and constant head tests. The hydraulic theories were then applied into the analysis to determine the permeability of the porous concrete samples.
Hydration Kinetics of Aluminate Cement Containing Magnesium Aluminate Spinel
Authors: Cai Bi Ya , Li Jin Hong , Ma Hong Wen , Jiang Xiao Qian
Published: July 2011

The hydration heat of aluminate cement containing magnesium aluminate spinel (MA-spinel) and Commercial Lafarge cement are studied. The results show that five stages exist in the hydration processes of both cements, e.g. pre-induction, induction, acceleration, deceleration and stabilization stage. TheNvalues of the two cements are both lower than 1 in acceleration stage, on the contary higher than 1 in stabilization stage. As a result, the hydration is mainly controlled by nucleation reaction and diffusion process in acceleration stage and stabilization stage respectively. The hydration heat of aluminate cement containing MA-spinel is lower than Lafarge cement. Accordingly, the hydration rate of aluminate cement containing MA-spinel is slower than that of Lafarge cement.
Experimental Study on the Fundamental Characteristics of Recycled Concrete
Authors: Chen Ai Jiu , Wang Jing , Ge Zhan Fang
Published: July 2011

At present, there are not any systematic researches on the fundamental performance of recycled concrete(RC). Thus it incites the inadequate confidence for the usage of RC. In this thesis, four different kinds of RC whose strength are C20、C25、C30、C35 respectively,are made using various mixing proportion. Then the influence rule of different recycled aggregate mixture quantities is drawn out, which consists the impacts on compressive strength, axial compressive strength, splitting strength, elastic modulus as well as the bending strength of RC. Meanwhile, the relation between the cubic compressive strength and the splitting strength, elastic modulus, axial compressive strength, bending strength is imitated, which provides study basis for the using of wasted concrete.
Enhancing Electrochromic Property of 1,4­-Di(thiophen­-3­-Yl)benzene by Copolymerization with Pyrene
Authors: Ou Yang Mi , Wang Geng Hao , Yu Zhen Wei , Zhang Cheng , Ma Chun An
Published: July 2011

A copolymer based on 1,4-di(thiophen-3­yl)benzene and pyrene was electrochemically synthesized and characterized. The copolymer film showed a stable and well-defined redox process. Furthermore, five various colors under different potentials were presented on the copolymer film. Besides, the copolymer film showed fast switching time (1.5 s at 750 nm, 1.0 s at 1100 nm). Cyclic voltammetry study reveals that the copolymer film has reasonable stability.
Localized Vibrational Mode in Manganese-Doped Zinc Sulphide and Cadmium Sulphide Nanoparticles
Authors: Ragam M. , Sankar N. , Ramachandran K.
Published: July 2011

Defect modes in ZnS:Mn and CdS:Mn nanoparticles are investigated by means of Fourier transform infrared spectroscopy and the Raman technique for local vibrational modes (LVM), and the observed modes are explained theoretically by using a molecular model.
Analysis of Finite Element Discretisation Schemes for Multi-Phase Darcy Flow
Authors: Adhikary Deepak P. , Wilkins Andy H.
Published: July 2011

We demonstrate that care must be taken in a finite-element discretisation of multi-phase compressible Darcy flow, otherwise constraints of non-negativity of fluid mass can become violated. Generalising a technique pioneered by Dalen, a lumped, finite-difference-inspired approximation with upstream weighting is described. This is numerically cheap, physically elegant, and the fluid mass at all nodes remains non-negative.
Polyphone Disambiguation Based on Maximum Entropy Model in Mandarin Grapheme-to-Phoneme Conversion
Authors: Liu Fang Zhou , Zhou You
Published: July 2011

Polyphone disambiguation is the core issue of the grapheme-to-phoneme (G2P) conversion in Mandarin Text-to-Speech (TTS) system. In this paper, we propose a maximum entropy (ME) model to disambiguate polyphones, and evaluate various keyword selection approaches in different domains. Furthermore, we design a hierarchical clustering algorithm for automatic generation of feature templates, which minimizes the need for human supervision during ME model training. Results of comparative experiments show that, for the task of polyphone disambiguation, ME model obviously outperforms decision tree (DT), log-likelihood ratio is the best scoring measure of keyword selection, compared to manual templates, templates automatically generated by our hierarchical clustering algorithm significantly improve the accuracy of polyphone disambiguation, and greatly reduce the size of the ME model.
A Computational Method of Salvo Fixed Lead Angle for Wake-Homing Torpedo
Authors: Wu Di Xiao , Jiang Tao
Published: July 2011

Fixed lead angle is an essential element of torpedo salvo data compendium preparation。On the basis of the characteristics and clear conditions of wake auto guided torpedo‘s salvo，a method of computing fixed lead angle was put forward and A computation example by proposed method was given. The computation result shows that the proposed method is effective and practical.
Optimization Variation for Multiple Heuristic Approaches in Solar Tracking
Authors: Fam D.F. , Koh S.P. , Kiong Tiong Sieh , Chong K.H.
Published: July 2011

The solar tracker, a device that keeps PV or photo-thermal panels in an optimum position perpendicular to the solar radiation during daylight hours, increases the collected energy and can be considered as one of the economical renewable energy in generating electricity. The current trend in solar concentrator tracking system is to use an open-loop local controller that computes the direction of the solar vector based on geographical location and time. It is not accurate because it has error from computing the intensity variation. Literature suggested that the photovoltaic panels could produce maximum power if the panels have angle of inclination zero degree to the sun position. In this research, genetic algorithm is one of the optimization techniques used to maximize the performance of solar tracking system. Research shows that among the heuristic approaches within 50 generation, Genetic Algorithm reaches the best fitness value at 0.01706 with optimum voltage 10.05V.
Topology Optimization for Vertical Electrochemical Machine Tool Based on FEA
Authors: Wang Yong , Zhu Guo Niu , Chen Yuan Long
Published: July 2011

Electrochemical machining is a process combined with electrochemical and mechanical actions. It has the advantage of higher efficiency, lower surface roughness, better quality and simpler equipment etc. According to the current development, topology optimization was introduced for the improvement of electrochemical machine tool and applied by the ANSYS software in this paper. Based on the result of the topology optimization, some improvement was done to the electrochemical machine tool. On the basis of the new FE model of the improved machine tool, the modal analysis and static analysis were carried out. By the comparison of the results between the former and latter, the weight of the machine tool is substantially reduced while the stiffness and strength reserved.
Attitude Controller Design for a Six-Rotor Type MAV
Authors: Wang Wei , Song Yu Ze , Nonami Kenzo , Cheng Yong , Zhou Yong , Wang Feng
Published: July 2011

MAV (Micro Air Vehicle) can be used for many applications such as the investigation of inhospitable environments, regions contaminated by nuclear pollution or hazardous material and other inaccessible areas. For such kind of purposes, a small machine that can autonomously fly seems to be appropriate. Our MAV research group selects a Quad-Rotor MAV as our platform, and achieved automated take-off, landing, hovering, way-point navigation, vision-based navigation flight. However, the payload of our current platform is low (about 500grams), and the flight duration is only about 10 minutes. To overcome these obstacles, we designed a Six-Rotor type MAV with 770mm of diameter, 1.9Kg of weight, 1.5Kg of payload and 12 minutes of flight duration (without payload). In this paper, we present the main design considerations which are essential for the construction of Six-Rotor type MAV and attitude controller design technique.
Research on Item Model in Content-Based Filtering Recommender Systems
Authors: Gong Song Jie
Published: July 2011

With the popularization of the Internet and the development of E-commerce, the information on the Networks has increased greatly and the E-Commerce system’s structure becomes more complicated when it provides more and more choices for users. People all have experienced the feeling of being overwhelmed by the number of new books, articles, and movies coming out each year. Many researchers pay more attention on building a proper tool which can help users obtain personalized resources. Personalized recommender systems are one such software tool in which information retrieve, information filtering, and content-based filtering techniques are used to help users obtain recommendations for unseen items based on their preferences. In this paper, described item models in content-based filtering recommender systems in order to alleviate the information overload issues. The paper presented three item models as following: vector space model representation, probability model representation and improved probabilistic model representation. These item models have their own advantages and disadvantages, and can choose according to specific circumstances.