bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase Structure and Piezoelectric Properties of (K0.5Nb0.5)NbO3 - CaZrO3 Ceramics
Authors: Myoung Pyo Chun
Published: June 2014

Lead-free piezoelectric ceramics of (1-x)(K0.5Na0.5)NbO3 - xCaZrO3 (abbreviated as KNN-CZ, x = 0 ~ 0.04) were synthesized by the conventional solid state method. Their phase structures and piezoelectric properties were investigated with x-ray diffraction (XRD), Scanning Electron Microscope (SEM), d33 meter and Impedance Analyzer. KNN-CZ samples exhibit only pure perovskite phases with a small monoclinic distortion. It was observed that the lattice parameter b has a maximum at x = 0.02 but the monoclinic distortion angle β shows a minimum at the same composition. From the dependence of the lattice parameters (a, b, c, β) and cell volume on the content of CZ, it is considered that the intermediate phase transition exists near at x = 0.02. Piezoelectric properties show the maximum value of d33 = 121 pC/N and kp = 0.35 for the sample with x = 0.02, which seems to be due to the co-existence of the two different phases.
The Scheme Comparison of Integral Structure after Adding Steel Storey to Concrete Frame
Authors: Sun Ning , Shu Gan Ping , Wang Zhi Ming
Published: June 2014

Characteristics and applying conditions of lightweight steel structures in adding buildings are introduced, and the correlative calculating methods in designing are also discussed. The optimal layers in adding are proposed by using bottom storey shear as target parameters. The reactions of structure adding optimal layers are analyzed to judge the adding capacity of original structure. The economy comparison of different materials in adding is also discussed by the parameter of material cost. Using an adding project as an example, an appropriate adding scheme is chosen by this method.
Research on Chemical Degradation of PAM in Oil Recovery Application
Authors: Liu Rong Wei
Published: June 2014

This paper is closely related to chemical degradation of PAM. The degradation refers to any process that breaks down the molecular structure of macromolecules. The most important degradation pathways in oil recovery applications are oxidation reduction, ironic ions and divalents. The influences of each factor is discussed, and preventive measures are also put forward. It is beneficial to provide the degradation of the polymer, and it can largely improve the utilization rate of PAM.
TURBISCAN: History, Development, Application to Colloids and Dispersions
Authors: Liu Ze Quan , Yang Xue , Zhang Qiang
Published: June 2014

Turbiscan is a new rapid and nondestructive method that has found increasing use in detecting physical destabilisation of concentrated and liquid dispersions. This review introduces the history and development of Tubiscan and focuses on applications of Turbiscan. The applications of Tubican were wildly used in dispersion stability of drug, carbon nanotubes dispersion, alumina suspension, emulsion stabilization and sedimentation behavior studying.
Activating of Nickel Slag and Preparing of Cementitious Materials for Backfilling
Authors: Li Ke Qing , Zhang Yang Yi , Zhao Peng , Feng Lin
Published: June 2014

The back-filling method is distinguished from other mining methods by its higher cost. In order to solve this problem and utilize water-granulated nickel slag as much as possible, nickel slag from flash smelting operation was used to prepare cementitious materials for backfilling. Approaches including mechanical activation and chemical activation were adopted to improve the cementitious activity of the slag. By taking the strength of the backfill materials as the evaluation standards, the hydration activity and cementitious performance of the slag were investigated under different activation conditions, and the mechanism of chemical activation was analyzed. The results shows that cementing agent prepared by using mainly the slag (occupying 85% of the total raw materials) can be used to replace cement and meet the production requirements for backfilling materials.
Nucleation, Crystallization and Characterization of Mica-Based Glass-Ceramics with Fluorapatite
Authors: Bai Jia , Chaysuwan Duangrudee
Published: June 2014

The glass system of SiO2-Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 was used to prepare machinable glass-ceramics for restorative dental applications. The aim of this study was to apply various heat treatments to produce mica-based glass-ceramics. Differential Thermal Analysis (DTA) was used to determine the optimal heat treatment conditions for nucleation and growth of the crystalline phases in the quenched glass. It was found that the optimum nucleation temperatures for the first and the second crystallization temperatures (Tp1 and Tp2) were 642°C and 635°C, respectively, and the optimum nucleation times were between 2 and 4 hours. X-Ray Diffraction (XRD) showed the phases developed were anorthite, calcium-mica, fluorapatite, strontium apatite, forsterite, fluorite and stishovite phases. The microstructures of glass-ceramics were observed by Scanning electron microscope (SEM), found to exhibit plate-like mica crystals with high interlocking and randomly oriented with a higher soaking temperature and prolongation of the soaking time for crystallization.
Microstructure Refinement and Crack Initiation in the Forging Process
Authors: Zhao Wen Long , Ma Qing Xian
Published: June 2014

In this paper, the type and morphology of defects in heavy ingots were detected mainly on the basis of experimental results, which were obtained by metallographic analysis of the materials dissected from one 380 ton 30Cr2Ni4MoV ingot. Then the evolution of typical defects in the forging process was investigated at temperatures ranging from 900°C to 1200°C and reduction ratios ranging from 0% to 50%. It was shown that coarse grains and inclusions were the main types of defects. In the forging process, the refinement of coarse grains and crack initiation at inclusions were summarized respectively with respect to temperature, reduction ratio and multi-pass forging. The microstructure evolution of 30Cr2Ni4MoV steel is accompanied by the formation of fine grains on condition that multi-pass forging or an optimal reduction ratio of 10% is adopted at temperatures lower than 1000°C, while temperatures higher than 1100°C can lead up to coarse grains. Besides, cracks originate from CaO and FeS inclusions at 900°C and 1000°C related to intense shear stress and melting of the FeS-Fe eutectics distributing along grain boundaries.
Numerical Simulation of One Pulse Power Laser Shock Peening
Authors: Chen Lei
Published: June 2014

Laser shock peening (LSP) is a novel technology of surface treatment. LSP utilizes a short laser pulse with high energy density, which induced a high pressure stress wave propagation and residual compressive stress on material surface. The effects of LSP of SAE9310 steel with a laser pulse of 14.2J at 2.9mm square beam have been studied by finite element method. The underlying formulation is based on Lagangian elastoplastic materials model. The propagation of shock wave, residual stress and plastic strain are simulated. The simulations show that the residual stress is mainly in the radial direction of the workpiece, and nearly zero in the longitudinal direction. The plastic strain remains on the processed surface dominantly. Divergences between theoretical and experimental residual stress occur due to the simplification of shock peening conditions.
CFD Simulation on Hydrodynamics of Liquid-Liquid Slug Flow in Microchannel
Authors: Wang Yi
Published: June 2014

Hydrodynamics in a liquid-liquid slug flow in a T-junction microchannel of 600μm diameter, operated under a squeezing regime, was simulated with the computational fluid dynamics method. The slug flow generation simulated shows very good agreement with experimental snapshots where the clear slug formation takes place in the vicinity of the T-junction. The internal circulation within each slug was also obtained, which could make us better understand the hydrodynamics of liquid-liquid slug flow in microchannel.
Study on CMT Welding of Stainless Steel Railway Vehicle Body
Authors: Wang Wen Quan , Meng Qing Liang , Niu Li Yuan
Published: June 2014

Abstract. Cold metal transfer (CMT) process is a modified inert gas metal welding process,which characterizes of low heat input and no spatter welding comparing with traditional GMAW process.In this paper,research of the CMT welding features of stainless steel sheet has been conducted.The effects of welding parameters including wire feed rate,welding speed and arc-length modification coefficient on mechanical properties and surface morphology were investigated.In addition,optical micrograph(OM) and scanning electron microscope(SEM) were used to analyze the weld microstructure,and microstructural characteristics were discussed as well.In the end,the optimum welding parameters which were used in real production and achieved good effect were obtained by means of orthogonal experiment.
Adhesive Systems for the Production of Multi-Layer Bonded Fabrics for Composite Applications
Authors: Käppler Iris , Younes Ayham , Bardl Georg , Cherif Chokri
Published: June 2014

Nowadays Non-Crimp Fabrics (NCF) are of substantial use in the field of technical textiles. Due to their lightweight, multilayer set-up, NCF became to an important factor for several technology sectors, i. e. automotive, wind energy and civil engineering. In order to eliminate known drawbacks of current manufacturing technologies, to enhance mechanical properties and to increase production speed of such NCF, a novel technology is proposed. This manufacturing technique is based on the adhesive bonding of layers made of high-performance fibres. Different adhesives were investigated to check their wettability and adhesion properties in relation to the high-performance fibres made of carbon or glass. Furthermore, the interface between the adhesive and a classical matrix for fibre-reinforced plastics was examined.
Numerical Simulation Study of the Influence of Turning Depth on the Bending Vibration Mode of Work-Piece
Authors: Wu Ming Ming , Li Shun Cai , Zhang Qiang
Published: June 2014

The mechanical models with and without thimble constraints for the turning work-piece are built respectively, applying ABAQUS software to analyze the modes of work-piece, then the law of the influence that different turning depth on the bending modes of work-piece is obtained. The study indicates that each-order natural frequency increase gradually in linear form for the work-piece without thimble constraint, while for the work-piece with thimble constraint, the natural frequency of the first four orders decrease linearly with the increase in the turning depth, but the change of high order frequency is relatively complicated.
Analysis of Grinding Roller Stress Distribution of Vertical Roller Mill
Authors: Jiang Xiao Hong , Ye Ping , Li Zong Kai
Published: June 2014

The quality of powder of non-metal materials directly relates to the force exerted on grinding roller, while the force on grinding roller relates to the thickness of the material layer. The uneven pressure distribution between the roller and material layer is caused by the drum-shaped characteristics of vertical mill grinding roller. This paper studies the pressure distribution of roller in compacted zones, established mathematical models of pressure distribution analysis, and provides a theoretical basis for improving the vertical mill production process as well as yield and quality of the powder.
Numerical Research of the Beryllia Ceramics Formation Process
Authors: Zhapbasbayev U.K. , Ramazanova G.I. , Sattinova Z.K.
Published: June 2014

Simulation results of the formation process of the ceramic fabrications by a hot molding method are presented. Mathematical model describes motion and heat exchange of the liquid thermoplastic slurry of beryllia including the aggregate state change. Velocity and temperature fields during the formation process in the bushings with flat cavity are obtained. Heat flow distribution at the wall of the form-building cavity is demonstrated. The increase of the slurry density during the transition from the liquid state into the viscous–plastic and solid–plastic states is defined.
The Optimal Levenberg-Marquardt Algorithm to Predict Welding Quality Using Mahalanobis Distance Theory
Authors: Kim Ill Soo , Wu Qian Qian , Lee Ji Hye , Lee Jong Pyo , Park Min Ho , Kim Young Su
Published: June 2014

With the development of computational technology, neural network has attracted the more and more attentions to reveal the relationships between the process parameters and welding geometry. However, the Gas Metal Arc (GMA) welding is complex and of multiple interactions so that mathematical model for welding parameters has not been achieved. Neural networks have been noted as being particularly advantageous for modeling systems which contain noisy, fuzzy and uncertain elements, while a sufficient algorithm is employed. In this study, Levenberg-Marquardt algorithm was employed into GMA welding process. Mahalanobis Distance (MD) was measured to determine the on-line welding quality to avoid joint failure as welding quality. To get an optimal neural network, cases with different configurations were carried out. The Root of the Mean sum of Squared (RMS) error was adopted to evaluate the accuracy of the prediction by neural networks with LM algorithm. The results presented that the proposed algorithm had the superiority of high accuracy that can be used in the on-line welding process.
Set-Up and Application of Thermal Fatigue Knowledge Ontology
Authors: Guo Cai Fen , Dong Zhi , Ning Hai Xia , Wan Chang Dong
Published: June 2014

In order to reuse and share thermal fatigue knowledge, the thermal fatigue knowledge ontology is exploited. The basic ontology relationship and characteristics are analyzed and the concept classification and axiom are devised. With the help of Protege3.1.1 software, the thermal fatigue knowledge ontology comes into being. Based on the crack axiom, the intelligent matching of thermal fatigue crack states of super-hard cutting tools is accomplished.
Void Formation and Growth at Solder-Bonded Interfaces in HP LEDs
Authors: Liu Wei , Jin Peng
Published: June 2014

Heat flux inside the HP LED chip is also increasing with the increasing drive current, integration and miniaturization of LED chips. The junction temperature of LED strongly depended on the heat transmission capacity of die attach layer, which provided the heat dissipation channel between the heat generating LED chips and the heat slug. The voids, interrmetallic compounds or a small delamination would lead to the increasing thermal resistance in the die attach layer. In this paper, the reliability of soldered-bonded interfaces was studied in high-brightness LEDs, which were prepared by Cree and currently available on the market. Results revealed that the higher drive currents would lead to the accelerated degradation or failure of treated LEDs. Additionally, the injection current had an important effect on void formation and growth at the solder-bonded interfaces. The larger drive current would induce the delamination between LED die and heat slug. This study provided some guidance for the end users and a theoretical basis for solder-bonded technologies.
Effect of Reserved Texture on Mechanical Properties of Cold Drawn Pearlitic Steel Wire
Authors: Zhou Li Chu , Zhao Yu Fei , Fang Feng
Published: June 2014

In this paper, pearlitic steel wire with/without reserved texture were investigated with the help of mechanical test system, scanning electron microscope (SEM) and XRD. Experimental result shows that: Tensile strength of two wire are almost same. After cold drawn tensile strength of wire with reserved texture are higher than tensile strength of the without one. Before cold drawn, two wires have same microstructure of isometric pearlite and after drawing the wire with reserved texture has less shear deformed pearlitic colony. Intensity of <110> fiber texture in the wire with reserved texture are stronger than the without one at all strains. The stronger <110> texture mean the orientation of α-ferrite lamella were more closely and improve working hardening rate of pearlitic wire.
The Application of Green Materials in Product Packaging Design
Authors: Ouyang Chao Ying , Li Lin , Xiong Ya Jie , Nie Xiao Li
Published: June 2014

Packaging requirements for products are increasingly high as society advances , the development of logistics. This paper revolves around the green material, through the selection of green materials and design concepts, analyzed the application of green materials in product design and its development trend. Through the knowledge of advanced materials, the better product design that meet market needs could be created, the value of the material could be unfolded, the Green Life period, the new style and new material of design could be created.
Mode I Crack Problem for a Functionally Graded Orthotropic COATING-Substrate Structure
Authors: Guo Li Fang , Li Xing , Yang You Zheng
Published: June 2014

In this paper, the Fourier integral transform-singular integral equation method is presented for the Mode I crack problem of the functionally graded orthotropic coating-substrate structure. The elastic property of the material is assumed vary continuously along the thickness direction. The principal directions of orthotropy are parallel and perpendicular to the boundaries of the strip. Numerical examples are presented to illustrate the effects of the crack length, the material nonhomogeneity and the thickness of coating on the stress intensity factors.
A Review of Numerical Study on Explosion and Shock Wave Resistance of Metal Foam Material
Authors: Yi Jian Kun , Shen Huang , Yan Ke Bin , Gao Bing
Published: June 2014

The goal of this research is to understand the status quo and trend of research on numerical simulation of explosion and shock wave resistance of metal foam material. Methods of modelling metal foam material and numerical algorithms of explosion and shock, as well as the current advances in two aspects have been briefly reviewed. Some problems existing in numerical simualtion of explosion and shock wave resistance of metal foam material have also been pointed out. Conclusions of this research will be of benefit to study explosion and shock wave resistance of metal foam material using numerical approach farther.
The Fracture Properties of Sandwich Structures Based on a Metal Foam Core
Authors: Shen Yi Ou , Li Yan , Cantwell Wesley , Zhao Yu Yuan
Published: June 2014

The fracture properties of a series of metal foam sandwich structures based on glass fiber-reinforced polyamide 6,6 composite (GF/PA6,6) skins have been investigated. The open cell core materials were manufactured using the Lost Carbonate Sintering (LCS) process, a recently-developed technique for manufacturing metal foams. Initially, the effect of varying the compaction pressure used in producing the metal foams as well as the density of the samples were investigated through a series of compression tests. Here, it was shown that the compressive strength and the elastic modulus of the foams varied with density and compaction pressure, in spite of the fact that the average size of the cells in these foams were insensitive to either of these two parameters. The resistance of sandwich structures to localized loading was investigated through a series of indentation tests. Here, it was shown that the indentation response of sandwich structures could be characterized using a simple indentation law, the parameters of which did not exhibit any clear dependency on the density of the foam. Finally, three point bend tests on the sandwich structures have shown that their loading-bearing properties were sensitive to foam density.
Research on Tribological Properties of Cast Iron at High-Speed Dry Sliding Condition
Authors: Yue Chen , Bao Shang Guan , Huang Ying Yu
Published: June 2014

The friction and wear properties of cast iron with different graphite morphologies and matrix microstructure were investigated at high speed dry sliding against GCr15 steel on the MMS-1G high-speed tribometer apparatus. The various wear micro-mechanisms and tribo-metallographic phases were studied by using scanning electron microscopy. The results show that as friction material, vermicular iron exhibits excellent comprehensive tribological properties. The friction coefficient of cast iron sliding against GCr15 decreases while the wear rate increases with the increase of sliding speed, friction coefficient and wear rate decline with the increase of pearlite content. Under the experimental condition, the main wear mechanisms of flake iron are abrasive wear, of vermicular iron are abrasive wear and oxidative wear and of nodular iron are oxidative wear, abrasive wear and fatigue spalling.
Validation of a Novel Method for Thermal Performance Evaluation of Parabolic Trough Receivers
Authors: Xiong Ya Xuan , Wu Yu Ting , Ma Chong Fang , Xu Peng , Li De Ying
Published: June 2014

Parabolic trough receivers are a kind of key components of a solar trough power plant, which absorb and transfer the high flux solar energy to the heat transfer fluid flowing in it. A Receiver Impedance Heating (RIH) method is put forward by analyzing the inadequacies of traditional methods. Voltage is imposed on both ends of the receiver and then the receiver is self-heated via a large electrical current flowing through it based on the Joule Effect. Once the receiver reaches a thermal equilibrium the product of voltage imposed on the receiver and electrical current flowing through the receiver is equal to the heat loss of the receiver to ambient environment at corresponding temperature difference of receiver temperature above ambient. The experiment system is simple, low-cost, and easy to operate. Experiment results show that curve of heat loss is smooth and measurement uncertainty is low, which means accuracy of the experiment results is high, while time period to reach a thermal equilibrium at every absorber temperature reduces to 2-3hours which is one fifth of that needed in traditional methods.
Analysis of Penetration-Explosion Warhead Fragments Distribution and Damage Efficiency
Authors: Zhang Peng Fei , Zhou Jian Ping
Published: June 2014

By means of theoretical calculation and LS-DYNA, fragments weight distribution law, fragments velocity and fragments distribution, fragments motion law and static dispersion range are compared. The two results are basically consistent. Analysis result proves that penetration-explosion warhead can form greater bound of valid fragment cluster.
Design and Optimization of the Bridge Expansion Joints Cleaning Machine
Authors: Jiang Jian Ping , Zhang Bao Xiang , Wang Ji Bao , Zhang Dong Yan , Wang Lei , Cheng Xiao Feng , Wu Cheng Ge
Published: June 2014

Bridges are hinges of city road and railway, which play an important function in national economy. The changes of temperature affect the length of the highway bridge beams, so the bridge should be equipped with the expansion joint device. When vehicles pass the bridge, dust flies up and clogs the gap of the bridges. The bridge expansion joints should be cleaned in time. The main task of this project is to study a kind of device used to clean the bridge expansion joints, which including two parts: the cleaning system and vacuum dust removal system. First, we use the sweeping wheels to loose dust, then the air-blower to blow away the dust. The optimization of vacuum dust removal system was discussed in this paper. Especially, the Cyclone dust removal device works well. The machine is of higher productivity, wide application, low energy consumption, simple structure compared with similar equipments.
Compatibility of Polyvinylidene Difluorid/Polyurethane and Preparation of Composite Tubular Membrane
Authors: Zuo Dan Ying , Li Hong Jun , Yi Chang Hai , Gan Hou Lei
Published: June 2014

The compatibility of polyvinylidene difluorid (PVDF) and polyurethane (PU), the thermodynamics of the PVDF/PU/DMF (N-N-Dimethylformamide) membrane-forming systems were studied, and the composite tubular membranes of PVDF/PU-PET knitted fabric tube were prepared by the immersion precipitation phase inversion method. The results showed that the PVDF/PU system was partly compatible by the measurements of the solubility parameter theory, the mixing enthalpy, the viscosity. With PU content increasing, the gelation values increased and the instantaneous liquid-liquid phase separation was preferred to occur. The water flux of the composite tubular membranes were enhanced from 1264.81 to 2165.35 L/m2.h with PU content increasing from 10wt% to 40wt%, which resulted from the an increment of the membrane porosity and the improvement of the hydrophilicity.
Initial Pressure Influence on Explosion Pressures of Methane-Air Deflagrations in Linked Vessels
Authors: Cui Yi Hu , Jiang Jun Cheng , Yu Yuan , Zhang Qing Wu
Published: June 2014

An experimental study on pressure evolution during closed explosion and venting progress of methane–air mixtures ([CH4=10%]) in linked vessels was performed, for systems at various initial pressures (P0=0-0.08MPa). The effects of initial pressure on regularity of pressure variation in vessels were discussed. For the closed explosion in isolated vessel, the higher level of the initial pressure in isolated big vessel is, the larger the peak pressure and rate of pressure rise is, and the peak pressure increases nonlinearly with initial pressure; For closed explosion in linked vessels, the higher initial pressure within the linked vessels system leads to the higher peak pressures in two vessels and there is an approximate linear relationship between them, which is similar to explosion in isolated vessel. For vented explosion in linked vessels at higher initial pressure, venting has poorer effect on protection of the linked vessels.
The Application of HPWM in Improving Vehicle Lateral Stability
Authors: Zhang An Jing , Xu Yan Hai , Lv Xin
Published: June 2014

The application of the High-frequency pulse width modulation (HPWM) for improving vehicle lateral stability is investigated in the paper. Firstly, a hydraulic control unit (HCU) combined with a high-speed switching valve (HSV) for controlling hydraulic oil pressure by adjusting duty cycle is presented. Then, a typical control strategy is described based on the application of HPWM. Finally, by using a 15dofs vehicle model, a simulation is carried out to investigate the role of HPWM on improving vehicle lateral stability. The results show that HPWM is capable to control the output pressure of HSV accurately and improve vehicle lateral stability effectively.
Preparation and Properties of Two-Dimensional Braid Heterogeneous-Reinforced Polyvinylidene Fluoride Hollow Fiber Membrane
Authors: Quan Quan , Xiao Chang Fa , Liu Hai Liang , Zhao Wei , Hu Xiao Yu , Huan Guo Lan
Published: June 2014

The two-dimensional braid heterogeneous-reinforced (BHR) polyvinylidene fluoride (PVDF) hollow fiber membranes which include PVDF polymer solutions (coating layer) and the two-dimensional braid as a reinforcement were prepared through the dry-wet spinning process. The influence of PVDF concentration in polymer solutions on performance of BHR hollow fiber membranes were investigated by terms of pure water flux, protein rejection, a mechanical strength test, and morphology observations by a scanning electron microscope (SEM). The results of this study indicated that the tensile strength of the BHR PVDF hollow fiber membranes was nearly 75 MPa and the hollow fiber membranes were endowed with better flexibility performance. The BHR PVDF hollow fiber membranes had a favorable interfacial bonding between the coating layer and the two-dimensional braid. The pure water flux decreased, while the rejection ratio increased with the increase of polymer concentration.
Design of a Reader Antenna for UHF RFID
Authors: Yang Hong , Guo Li
Published: June 2014

A compact and circular polarized antenna for UHF band RFID handset reader was designed, and realized by cutting slits in the antenna patch and etching slots on the ground. Numerical simulation was performed for the characteristics of the antenna with the software HFSS 13.0.The simulation results show that when the size of antenna patch is 68mm×68mm, -10dB return loss impedance bandwidth is 49MHz,VSWR is less than 2 and the largest gain is -0.61dB for antenna in 907～931MHz. Compared with the traditional reader antenna with the same material of the substrate，the improved antenna has a much higher gain．and the size was reduced by 20% and the max gain is raised -0.11dB.
An Improved Mean Filter Algorithm for Impulse Noise Elimination
Authors: Tang Wang , Tang Jin
Published: June 2014

Since the standard mean filter has some drawbacks, an improved mean filter is proposed in this paper to overcome them. In this improved algorithm, noise detection is used to find the noise which is caused by impulse wave in the image. Based on the result of noise detection, window size would be selected in the improved mean filter to minimize the influence of the noise. According to the result of computer simulation, it shows that the improved mean filter is much more efficient than the standard mean filter in eliminating the noise as well as in protecting the details of the image. It also shows its advantage in filtering speed.
A Model Integration Framework Based Portability for GNSS Simulation
Authors: Zhou Hong Wei , Hou Hong Tao , Zhang Wang Xun , Li Qun , Chang Qiang
Published: June 2014

Performance Simulation for Global Navigation Satellite System (GNSS) that be used for performance simulation and evaluation analysis of the GNSS, is a part of the critical algorithm test and system index analysis for GNSS. In this article, the requirements of GNSS are analyzed firstly, and the characteristic of model portability for GNSS is studied, then the model integration framework based on Simulation Model Portability is proposed. The system architecture consists of model design, development, integrating, executing and analysis. Lastly, the regional performance of GALILEO Navigation Satellite System in China is tested and analyzed based on the integration framework.
Low Temperature Preparation of Aluminum Titanate Film via Sol-Gel Method
Authors: Bao Yi , Jiang Wei Hui , Feng Guo , Liu Jian Min , Wu Qian
Published: June 2014

Aluminum titanate (Al2TiO5) film was prepared via sol-gel method at low temperature, using ethyl acetoacetate and anhydrous citric acid as compound chelating agent, tetrabutyl titanate (Ti (OC4H9)4) and aluminum chloride (AlCl3.6H2O) as precursors, ethanol as solvent. The phase transformation of Al2TiO5 xerogel during heat treatment, the effect of different chelating agents on the synthesis of Al2TiO5, and the phase composition and morphology of film were investigated by means of differential thermal and thermo gravimetric analysis (DTA-TG), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). The results demonstrate that Al2TiO5 can be synthesized at 750 °C by using compound chelating agent, rather than single chelating agent. Compound chelating agent contributes to the formation of Al-O-Ti heterogeneous bond, which is the key to preparing Al2TiO5 at low temperature. High quality Al2TiO5 film could be coated on the SiC substract at 750°C.
Epitaxial Pd-Doped LaFeO3 Films Grown on (100) SrTiO3 by Pulsed Laser Deposition
Authors: Duan Ying Wen
Published: June 2014

Single-crystalline, epitaxial LaFeO3 films with 5 at. % substitution of Pd on the Fe site are grown on (100) SrTiO3 substrate by pulsed-laser deposition technique. The epitaxial orientation relationships are (110)[001]LFPO||(100)[001]STO. X-ray diffraction and transmission electron microscopy reveal that the LFPO films have high structural quality and an atomically sharp LFPO/STO interface. After reduction treatments of as-grown LFPO films, very little Pd escaped the LFPO lattice onto the film surface, the formed Pd (100) particles are oriented epitaxially, and parallel to the LFPO films surface.
The Preparation of the Highly Preferred Orientation of Wurtzite Structure Zinc Oxide Films
Authors: Lan Lei Lei , Zhou Dan , Gu Guang Rui , Wu Bao Jia , Tian Lian Hua
Published: June 2014

Zinc oxide (ZnO) films are prepared on n-Si substrates by means of radio frequency (RF) magnetron sputtering method. The influences of substrate temperature on the crystal orientation and crystalline structure of ZnO films are investigated by X-ray diffraction (XRD) and Raman spectroscopy. The surface morphologies are studied by scanning electron microscope (SEM). It is indicated that ZnO films with wurtzite structure were successfully prepared. When the substrate temperature reduced to 100°C, the wurtzite structure with highly preferred orientation along the (002) plane of the ZnO film is prepared and the elliptical shape particles distributed uniformly on the ZnO film surface. The higher substrate temperature can offer more kinetic energy for mobility of particle on the surface to achieve other crystalline growth, resulting in the highly c-axis-oriented crystalline structure is destroyed.
Synthesis and Characterization of Emulsion Coating of Fluorinated Polymethacrylate Modified by POSS
Authors: Tian Bao Juan , Gao Jun Gang , Wang Chao
Published: June 2014

The core-shell nanocomposite particles were prepared from acrylate monomers and octavinyl polyhedral oligomeric silsesquioxane (V-POSS) by emulsion polymerization. The structure and properties of emulsion and latex film were characterized by FT-IR, dynamic mechanical analysis (DMA) and TEM and laser particle diameter analyzer (LPDA). The results showed that the V-POSS/polyacrylated (V-POSS/PMA) composite latexes was prepared and the diameter is about 36.1 nm when added 5wt% V-POSS. DMA results showed that the mechanical loss (tanδ) peak temperature (Tp) of the film enhance with increasing V-POSS content and had the best high Tp at 88.4°C for added 7 wt% V-POSS, which increased 7.8 °C than had not V-POSS. Thermogravimetric analysis (TGA) showed that the addition of V-POSS can increase the thermal decomposition temperature and improved the thermal stability of polyacrylate.
Synthesis of Core @ Shell Composite Particles with a Tunable Shell Containing Natural Urushiol
Authors: Zheng Long Hui , Chen Bao Ling , Huang Hai Bin , Chen Qin Hui , Lin Jin Huo
Published: June 2014

The core @ shell composite particles of polystyrene @ urushiol-titanium chelate polymer (PS @ UTi) was prepared through in-situ reaction between sulfonated polystyrene microspheres coated tetrabutyl titanate and urushiol. The resultant PS @ UTi was characterized by scanning electron microscope and transmission electron microscope. Results indicated that the PS @ UTi with the excellent properties of raw lacquer was synthesized. The shell thickness of UTi coated on PS was tunable by changing the sulfonation time.
The Facile Hydrothermal Preparation of WO3 and its Photocatalytic Performance under Visible-Light Irradiation
Authors: Li Fen Fen , Gao Hong Tao , Liu Guang Jun
Published: June 2014

The orthorhombic WO3 nanoplates were fabricated via a hydrothermal process, using HBF4 as the acid source. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis diffused reflectance spectroscopy (UV-Vis DRS), respectively. The WO3 nanoplates exhibited nice UV-light driven photocatalytic performance in the degradation of Rhodamine B (RhB).
Numerical Simulation of Synthetic Heat Transfer in Laminar Nanofluid in a Horizontal Pipe
Authors: Mirzaei Mohsen , Gishin Mostafa Jafari , Abbaspour Mohammad
Published: June 2014

In this study, the effect of solid-liquid volumetric ratio in laminar flow of nanofluid has been investigated numerically. The conservation equations are utilized in three dimensional elliptical forms for laminar and steady flow, and the effects of adding aluminum oxide nanoparticles to water based-fluid are studied. First, the influence of solid-liquid volumetric ratio on the secondary flow vortices, non-dimensional temperature is investigated for a flow with a fixed low Reynolds number and different Grashof numbers in a horizontal pipe. Then, the effect of variation in solid-liquid volumetric ratio on Nusselt number and convective heat transfer coefficient along the pipe is studied. The results of this study are in good agreement with the current literatures.
Preparation and Characterization of Polyacetylene/Expanded Graphite Composites
Authors: Hu Ming Ming , Song Lin Hua , Tao Bing Lin
Published: June 2014

Expanded graphite (EG) is a promising conducting filler to enhance the conductivity of the polyacetylene (PA)/EG composites and also an ideal support to catalyst PA to polymerize on the surface of EG. The expanded interlayers of EG prepared by chemical oxidation is between 100 and 1500 nm. Diameters of the Fe (naph)3 nanoparticles deposited on the external surface and internal surface (i.e. surface of the expanded graphitic layers) of EG range from 7 to15 nm. PA/EG composites were prepared by heterogeneous polymerization. PA catalyzed by Fe (naph)3 nanoparticles supported on the external surface and at the edge of the expanded layers was inclined to form bigger aggregation, while PA grown between the interlayers exhibit smaller size. The bulk conductivity of the prepared composites is 5.78×103 S·m-1.
Research of Properties on Li-Ion Batteries Based on a Polypyrrole Derivative Bearing TEMPO as a Cathode Material
Authors: Xu Li Huan , Yang Fang , Su Chang , Zhang Cheng
Published: June 2014

4-(3-(Pyrrol-1-yl) butyric acid base)-2,2,6,6-tetramethylpiperidin (Py-B-TEMPO) was synthesized by etherification reaction of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-yloxy. And the polymer of its monomer was prepared by chemical oxidative polymerization and the chemical structure and battery performance of the prepared materials were characterized comparably by Mass spectrometry, 1H NMR, FT-IR spectra and galvanostatic charge-discharge testing using simulant lithium ion half-cell method, respectively. The results shows that the introduction of the TEMPO group to the pyrrole could prevent the polymer from agglomeration and optimize the particle morphology of the resulting polymers, all of which made it demonstrate a significantly improved specific capacity of 86.5 mAh·g-1 (99% of the theoretical capacity) compared with PPy (21.7 mAh·g-1). Moreover, it gives an obvious voltage plateau of nearly 3.5 V which is comparable to the redox potential of TEMPO.
A High Rate, High Capacity and Long Life (LiFePO4+AC)/Li4Ti5O12 Hybrid Battery-Supercapacitor
Authors: Hu Xue Bu , Lin Zi Ji , Zhang Yong Long
Published: June 2014

A hybrid battery-supercapacitor (LiFePO4+AC)/Li4Ti5O12 using a Li4Ti5O12 anode and a LiFePO4/activated carbon (AC) composite cathode was built. The electrochemical performances of the hybrid battery-supercapacitor (LiFePO4+AC)/Li4Ti5O12 were characterized by constant current charge-discharge, rate charge-discharge, electrochemical impedance spectra, internal resistance, leakage current, self-discharge and cycle performance testing. The results show that (LiFePO4+AC)/Li4Ti5O12 hybrid battery-supercapacitors have rapid charge-discharge performance, high energy density, long cycle life, low resistance, low leakage current and self-discharge rate, which meet the requirements of practical power supply and can be applied in auxiliary power supplies for hybrid electric vehicles. At 4C rate, the capacity loss of (LiFePO4+AC)/Li4Ti5O12 hybrid battery-supercapacitors in constant current mode is no more than 7.71% after 2000 cycles, and the capacity loss in constant current-constant voltage mode is no more than 4.51% after 1500 cycles.
Theoretical Investigation on Rearrangement Mechanism of Fluoroalkylsilane
Authors: Zhou Yu Fang , Ma Qing Yu
Published: June 2014

Fluoroalkylsilanes are a kind of important carbofunctionalized silanes and applied in many fields. while the rearrangement and decomposition reactions could easily occur for these compounds under a certain high temperature or catalysis. In this work, we selected CH3H2SiCH2F as the molecular sample and investigated the mechanism of rearrangement reaction by using quantum chemical DFT methods. The results showed the rearrangement occurred via a transition state, in which the fluorine atom migrated from carbon to silicon and the hydrogen atom migrated from silicon to carbon. To understant the the process details the atomic charge distribution and electronic transfer were analyzed. And atomic vibrations spectra was discussed as well.
Failure Analysis of the Solder Joints in Flip-Chip BGA Packages under Free-Drop Test
Authors: Yuan Guo Zheng , Chen Xia , Shu Xue Feng
Published: June 2014

The failure of plastic ball grid array under intense dynamic loading was studied in the project. This paper presents the drop test reliability results of SnPb flip-chip on a standard JEDEC drop reliability test board. The failure mode and mechanism of planar array package in the drop test was comprehensively analyzed. High acceleration dropping test method was used to research the reliability of BGA (ball grid array) packages during the free-drop impact process. The model RS-DP-03A drop device was used to simulate the falling behavior of BGA chip packages under the real conditions, The drop condition meets the JEDEC22-B111 standards (pulse peak 1500g, pulse duration 0.5 ms) when dropping from the 650mm height . In the testing, according to the real-time changes of dynamic voltage, the relationship between drop times and different phases of package failure was analyzed. With the dye-penetrated method and optical microscopy, it was easy to observe the internal crack and failure locations. The growth mechanism of the cracks in solder joints under the condition of drop-free was analyzed and discussed.
TEM Study of AlGaN/GaN on Hexagonal SiC Substrates
Authors: Gkanatsiou Alexandra , Lioutas Christos B. , Frangis Nikolaos , Chandraraj Narendraraj , Polychroniadis Efstathios K. , Prystawko Pawel , Leszczynski Mike
Published: June 2014

The present work concerns the microstructural characterization of a multi-component (based on GaN and related materials) and multi-layered (5 layers) film, grown on 6H-SiC substrate (with a misorientation of 1 degree off from the (0001) plane), using transmission electron microscopy (TEM). The TEM characterization showed no surface undulation, despite the presence of steps in the SiC/AlN interface.
A Facile Method to Synthesize Responsive Magnetic Polymer Composite Nanoparticles with Multifunctional Groups
Authors: Pu Meng Lu , Jiang Wei , Shen Yue Qing
Published: June 2014

Magnetite nanoparticles (MNPs) coated with poly (divinylbenzene-co-glycidyl methacrylate) particles (mPDGs) are prepared by co-polymerization of 1,4-divinylbenzene and glycidyl methacrylate monomers via batch emulsion polymerization. The Fe3O4 nanoparticles modified by oleic acid are obtained by chemical precipitation. The chemical composition, morphology, magnetic content, magnetic properties and particle size of the composite particles are investigated using transmission electron microscopy, thermogravimetric analysis, vibrating sample magnetometer, and dynamic light scattering, respectively. The results show that the magnetic nanoparticles have been coated by 1,4-divinylbenzene and glycidyl methacrylate, with the high saturation magnetization being 33.66 emu/g. The mean size of the mPDGs with good dispersion is about 200 nm. Subsequently, the polymer shell with reactive epoxy group is expected to be useful for chemical grafting of any biomolecule containing reactive functional groups (-NH2, -OH, -COOH, etc) or can be chemically modified to desired functional groups. These magnetic nanospheres with multifunctional groups have potential application in biomedical applications.
Study on Structure Analysis and Cell Toxicity of Okra Polysaccharide
Authors: Min Li Jing
Published: June 2014

[Objective]The aim is to analysis okra polysaccharide component and structure, and study on the cell toxicity.[Method] In this paper, we used okra seeds as raw material, extracted okra polysaccharide by boiled alcohol sink method extraction, purified it, studied the mono-saccharide composition, and did okra polysaccharide cytotoxicity assay.[Results]The results show sugar content is 28.15% in the extracts form okra seeds, and the okra polysaccharides are composed of rhamnose, Arabian sugar, D-xylose, D - fructose and D-glucose as well as several monosaccharide composition, cytotoxicity assay shows that the cell toxicity of okra polysaccharide is similar to that of glucose. [Conclusion]This study provided experimental basis for the optimization and development of polysaccharide resources from okra.
Resveratrol Loaded Self-Microemulsifying Drug Delivery System (SMEDDS): Development and Optimization
Authors: Liu Guo Qing , Zhou Hua Feng , Zhang Jing , Yan Ze Min , Duan Ming Xing , Long Ying Fang , Xia Qiang
Published: June 2014

We developed a SMEDDS to enhance the oral delivery of resveratrol by using high performance liquid chromatography, a pseudo ternary phase diagram and a central composite design (CCD). We found that the optimal formulation of 12.69% greoil gtcc, 62.29% Cremophor EL, and 25.02% Labrasol. We characterized the particle size and zeta potential of the final SMEDDS.
Detoxification Capabilities of Adsorbents for Artificial Liver Support Devices: A Comparison
Authors: Ding Wei Ping , Zou Li Li , Pei Ying Ying , Sun Si Jie , Gao Da Yong
Published: June 2014

Adsorption performances of activated carbon Norit RO 0.8, neutral resin Amberlite XAD-7, anion resin Dowex 1x4 and cation resin Dowex 50wx4 were investigated in detail for artificial liver support devices. Firstly, equilibrium adsorption experiments of these adsorbents to albumin, creatinine, bilirubin, tryptophan and cholic acid were conducted respectively. Then their adsorption capacities were obtained by curve fitting. The results indicate that activated carbon Norit RO 0.8 and anion resin Dowex 1x4 are two better adsorbents for removing toxins. Lastly, adsorption rate constants of activated carbon Norit RO 0.8 and anion resin Dowex 1x4 to all above solutes were studied with pseudo-first and second-order kinetic adsorption models. The results show that the toxin adsorption rate of anion resin Dowex 1x4 is faster than that of activated carbon Norit RO 0.8. The systematical experimental results in this paper are very important references for researchers in the field of blood purification based on adsorption technology.
Potassium Dichromate Surface Modification of Poly-Lactic Acid (PLA) and Poly-Lactide-Co-Glycolide (PGLA) Fibers
Authors: Wang Bi Qiao , Zhang Pei Hua , Fang Mei Han
Published: June 2014

PLA and PGLA, as biodegradable polymers, are widely used in the biomedical field, such as in surgical sutures, drug delivery devices, and tissue engineering research and so on. However, the lack of hydrophilic groups on their surfaces limit their application. For improving hydrophilicity of PGA and PGLA fibers, and preserving fiber mechanical property at the same time, PLA and PGLA fibers were modified by potassium dichromate solution for different processing time for optimizing modification parameter. Breaking strength and water contact angle were tested to observe the change of properties, differential scanning calorimeter (DSC) and fourier transform infrared spectrometry (FTIR) were used to analyse the change of molecular structure and functional groups. Experimental results showed that 6min was the most suitable time for improving hydrophilicity of PLA and PGLA fibers and preserve fiber mechanical property.