bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Roller Compacted Concrete Graduation with Vibration Liquefaction
Authors: Liu Hai Wen , Tian Bo , Hou Rong Guo , Li Sili
Published: December 2013

In the rolling process, reasonable way of grading and rolling can improve the compactness and anti-permeability of roller compacted concrete (RCC), as well can make its strength meet the design requirements. Vibration liquefaction is the key step for RCC in the rolling process. Therefore, this paper first puts forward the more suitable method, Modified Vebe Vibration Liquefaction Test, to account for the characteristics of vibration liquefaction in RCC, and then, studies the coarse aggregate gradation scope using aggregate gradually filling theory. Though Modified Vebe Vibration Liquefaction Test, the research show that the aggregate VCA and the characteristics of vibration liquefaction of RCC have a good correlation. Finally, by studying the sand ratio and fineness modulus of sand how to affect the performance of liquefied RCC, the optimum value range of sand ratio and fineness modulus of sand was determined.
Study on Vibrational Liquefaction Behavior of Air-Entrained Concrete
Authors: Hou Zi Yi , Yuan Ye Zhen , Yuan Zu Guang , Liang Yang De , Zhou Ze Han
Published: December 2013

With respect to the liquefaction behavior of cement concrete material in a vibrational condition, the varying patterns of the vibrational viscosity coefficients, vibrational energy transfer and rheological mechanical behavior of air-entrained concrete and non-air-entrained concrete in a vibrational shear condition were compared by analyzing the vibrational liquefaction processes of concrete. The study has found that the vibrational viscosity coefficient of concrete with air entraining agent added increased notably so that air-entrained concrete can maintain good shuttering behavior during slip-form construction; presence of a large number of tiny bubbles in air-entrained concrete allowed more even transfer of vibrational energy in concrete; and the rheological mechanical behavior of concrete was improved after air entraining agents were added so that it became easier to liquefy by vibration and had better shaping effect upon completion of vibration. Keywords: air-entrained concrete, slip-form construction, cement concrete pavement, vibrational liquefaction
Influences on the Axle Load Stress of the Cement-Concrete Pavement Structure Caused by the Crack or Cutting Crack of the Semi-Rigid Base
Authors: Yang Bin , Tan Hua , Deng Jia Xi , Pang Chan
Published: December 2013

Some horizontal cracks will appear during the strength formation of the semi-rigid base, for the influences of dry shrinkage and temperature shrinkage exist, so the engineers often adopt the manual method of equidistant cutting crack to avoid the irregular cracks. In order to analyse the influences on the axle load stress of the cement-concrete pavement slab which caused by the width and position of the base cracks or cutting cracks, the 3D FEM was used to study them under the different working conditions considering the crack, width and position. By the above research, the results show the existing cracks affect the integrity and continuity of the pavement structure; The crack width has no large influence on the stress of the pavement slab, while the base stress decreases apparently with the increasing width, and it becomes stable finally; The stress of the pavement slab is maximum when the crack or cutting crack is located in the middle, while it's small when the crack or cutting crack is located in the one fourth of the pavement slab.
Influence of Paving Condition on Longitudinal Cracking of Portland Cement Concrete Pavement
Authors: Han Li Zhi , Chen Liang Liang , Tian Bo
Published: December 2013

The curling stresses of rigid pavement are the result of in-situ and built-in temperature gradient. A profound investigation on the reasons causing longitudinal cracking (LC) was conducted in this paper. Based on finite element method (FEM) analysis results obtained from ISLAB 2000, the wheel load stress generated by a single axle load that is applied along the transverse joints is considered to be the critical loading condition for longitudinal cracking. Nonlinear environmental stress due to the curling of Portland Cement Concrete (PCC) was analyzed using the numerical program developed in this study; the paving time within a day has a significant influence on the curling stresses at the top portion of PCC slab at the critical loading position for longitudinal cracking. Research in this paper proposed an analytical method to determine the influence of the paving condition (day time and night time) on the built-in setting gradient and its effect on the in-situ effective equivalent temperature differential.
Research of Built-In Temperature and Zero Stress Temperature of Cement Concrete Pavement at Early Ages
Authors: Hu Chang Bin , Du Mu Lu , Wang Li Juan
Published: December 2013

Based on field tests and numerical simulation methods, distribution characteristics of early-age built-in temperature of cement concrete pavement constructed in different seasons and pouring time were analyzed firstly. Then considering effect of creep, characteristics of early-age zero stress temperature in cement concrete that built-in temperature of cement concrete pavement constructed in different seasons and pouring time has a great difference. The distributions of built-in temperature along the thickness present nonlinear obviously, and they have four typical types: concave and positive gradient type, concave negative gradient type, convex positive gradient type and convex negative gradient type. Zero stress temperature gradient shows prominently developing process compared with built-in temperature of slab at different ages by the effect of creep. Zero stress temperature of slab poured on am7:00 in summer firstly increase and then decline. Besides, the positive gradient change to negative gradient gradually, and the gradient of zero stress temperature trend to decrease. At last, it is recommended to calculate zero stress temperature of slab consideration of base temperature and the nonlinear distributions characteristics, and the combined effect of creep and age.
The Relationship between Concrete Road Performance and Salt Frost
Authors: Zhou Sheng Bo , Shen Ai Qin
Published: December 2013

To carry out frost resistance, resistance to chlorine ion permeability, abrasion resistance and flexural tensile strength test for different mixture ratio of concrete, the influence of salt frost was systematically analyzed on the other concrete road performance. The results show that the salt frost made the decrease of strength of concrete, resistance to chloride ion penetration reduce, but had a little effects on abrasion resistance.
Research on the Construction Technology of Cross-Prestressed Concrete Pavement
Authors: Han Wei Wei , Zhang Dong Sheng , Li Na , Xu Xi Juan , Jia De Sheng
Published: December 2013

Cross-prestressed concrete pavement, without setting expansion joints, can extend its service life, improve its bearing capacity and make the continuous construction possible. In recent years, it has been successfully applied to toll plazas, short subgrade of the highway and the overweight or overloaded road. Materials choosing, construction method of the cross-prestressed concrete pavement was presented in details and some relevant problems during the construction have been discussed in this paper.
Characteristics and Methods Research on Heavy Compaction and Vibration Compaction of Graded Crushed Aggregate
Authors: Liu Hong Hai , Zhang Zhi Geng , Liu Nieyangzi , Ma Deng Cheng
Published: December 2013

Graded crushed aggregate mixture form internal friction resistance rely on the interlocking and friction effects between the particles ,with high shear strength and resistance to deformation, which is difficult to compacted. Through the analysis of factors affecting the compaction properties of materials,self-vibration phenomenon and resonance phenomenon,theoretical study on the effect of shear strength of the material vibration, the comparative experiments were conducted by heavy compaction instrument and vibration compaction instrument,accommodate compaction property of graded crushed aggregate,the test methods were obtained,also the test parameters were determined, and verified by experiment.
Investigation of the Deformable Behavior of Loose and Dense Sand through DEM
Authors: Yang Yi , Huang Run Qiu , Cheng Yung Ming , Wang Jian Feng
Published: December 2013

The deformable behavior of ideal granular material under external loading, especially in monotonic condition, has always been of keen interest to geotechnical engineers. Earlier researchers have reproduced the fundamental stress-strain-dilation relationships at macro scale by distinct element method (DEM). Particle shape and servo controlled boundary are always assumed to be in regular and rigid conditions. In this paper, the elongated particles are prepared for generating loose and dense consolidated specimen. Meanwhile, lateral flexible boundary is applied for simulatingthe visualizedshear band, where the confining stress is fixed at 50kPa for loading procedure. The evaluations of macro qualities or micro statistical indexes are presented for finding the characteristic states of Quasi-static shear deformation. The results indicate that the initial particles internal contact and spatial arrangement would govern the followed shearing behavior.
Melt Time-Temperature Treatment Affecting the Amorphous Ribbons' Properties of the HTS-42 Solder
Authors: Tsepelev Vladimir , Konashkov Viktor , Vyukhin Vladimir , Povodator Arkadi , Latipova Ann
Published: December 2013

The HTS-42 (High Temperature Solder) properties in the liquid state have been studied. The optimal operating conditions for the solder melt time-temperature treatment, used for producing amorphous ribbons having the specified service properties, are recommended based on the analysis of the anomalies properties and temperature polytherms shape. The subsequent thermal treatment of soldered joints is not shown appropriate for soldering homogeneous melts not hardened by age (precipitation) hardening. The strength of such products can be improved by increasing the contact joint area. The HTS-42 solder amorphous ribbons enable, as compared to the powder semi-finished product, reducing its consumption by 2-3 times, improving the carrying capacity of soldered constructions by 20-40 %, which makes the soldering practice resource saving and significantly improves the product reliability.
Study of Wear Resistance of Sintered Powder Tool Materials
Authors: Vereschaka A.A. , Migranov M.S.
Published: December 2013

The purpose of the studies presented in this paper was to improve cutting properties of tool made of powder metal high-speed steel due to controlling the conditions of friction on contact areas of edgetools at cutting temperatures. Control of friction was carried out on the basis of alloying steel with 5% aluminum oxide (Al2O3), introducing 2% additive agent BN, and that allowed forming stable high-strength secondary structures, significantly extending the intervals of material self-organization. The use of both variants in alloying steel with 20% additive agent TiCN allowed significantly increasing lifetime of tool made of powder metal high-speed steel.
Tensile Properties of Untreated and Treated Long Kenaf Fiber/Polyester Composites
Authors: Hamzah Norhazlin , Taib En Yakub Md , Bakar Mimi Azlina Abu
Published: December 2013

The interest in using fibers as reinforcement in composites has increased in recent years due to its lightweight, combustible, non-toxic, non-abrasive, low cost and biodegradable properties. In this study, two difference types of long kenaf fiber (LKF) used in fiber-reinforced composites which are untreated and treated with 1% sodium hydroxide (NaOH). The volume fraction of LKF used are 20%, 25% and 30% prepared by cold pressed hand lay-up technique were investigated. A series of tensile tests were performed to evaluate the effect of their modulus and ultimate tensile strength (UTS). The morphological and structural changes of the fibers were investigated by using scanning electron microscopy (SEM). It has found that the treated long kenaf fiber (TLKF) shows the higher value of tensile strength compared to untreated long kenaf fiber (ULKF).
Fracture Toughness of Treated OPEFB Filled Polymer Nanocomposites at Different Clay Loading
Authors: Fadzil Nur Amanina Mohd , Kalam Anizah , Jumahat Aidah , Taib Yakub Md. , Razak Noorrul Wahida Abdul
Published: December 2013

Two different clay loadings were added to OPEFB/PP/MAPP which was 7 phr and 10 phr in order to see its effect on the fracture toughness. Standard dimension of samples was prepared for 180 μm, 355 μm and 355 μm treated with 1% NaOH. The result showed that 7 phr clay contents had the highest fracture toughness of 1.16 MPa.m1/2. Alkali treatment on OPEFB fiber gave 7% improvement of fracture toughness for samples with 7 phr PPnanoclay loading. SEM images show the improvement of bonding between the fibers and the matrix upon alkali treatment.
Risk Assessment Method and Protection Goals of High Concrete Gravity Dam Subjected to Far-Field Underwater Nuclear Explosion
Authors: Lu Lu , Li Xin , Zhou Jing
Published: December 2013

The nucleus threat and hydraulic engineering's security problem are two focal point problems. At present, a new problem associated with the two problems has not systematically investigated and full understanding. This paper propose that the damage spectrum is used to predict the damage state of the concrete dam subject to far-field underwater nuclear explosion, and the environmental pollution factor is added in the risk assessment model. Finally, the protection design targets is mathematical described.
The Novel Polishing Characteristics for GaAs Based Diode Lasers Wafer
Authors: Li Zai Jin , Zheng Xiao Gang , Li Te , Qu Yi , Bo Bao Xue , Liu Guo Jun , Ma Xiao Hui
Published: December 2013

A novel polishing technology for the GaAs based diode lasers wafer is presented. Designed for technological simplicity and minimum damage generated within the GaAs based diode lasers wafer. It combines GaAs based diode lasers wafer polishing with three conditions consisting of (1) removal of thermodynamically unstable species and (2) surface oxide layers must be completely removed after thermal cleaning, and (3) a smooth surface must be provide. Revolving ultrasonic atomization technology is adopted in the polishing process. At first impurity removal is achieved by organic solvents, second NH4OH:H2O2:H2O=1:1:10 solution and HCl:H2O2:H2O=1:1:20 solution in succession to etch a very thin layer, the goal of the step is removing contaminants and forming a very thin oxidation layer on the GaAs based diode lasers wafer, NH4OH:H2O=1:5 solution is used as the removed oxide layers in the end. The effectiveness of the process is demonstrated by operation of GaAs based diode lasers wafer, characterization of the oxide composition was carried out by X-ray photoelectron spectroscopy,and surface morphology was observed by total reflection X-ray fluorescence spectroscopy and atomic force microscope. The research results show that the polished surface without contamination, and the n-side surface are very smooth.
Broad-Band Electroluminescence from Highly Stacked InAs Quantum Dot at Telecom-Band
Authors: Akahane Kouichi , Yamamoto Naokatsu , Kawanishi Tetsuya
Published: December 2013

We have developed a growth procedure for increasing the number of stacked layers of InAs quantum dots (QDs) on an InP(311)B substrate that is resistant to defects and dislocations. In this work, we also developed a modulated stacking structure consisting of various size QDs for electroluminescence (EL). This promotes broad-band emission because each QD-distributed wide range can emit a different wavelength. The EL spectrum of this sample was measured with pulsed current injection. There was a strong emission from the ground state at approximately 1524 nm which is suitable for fiber-optic communications, with an injection current of 100 mA at room temperature. The full width at half maximum was 213 nm. Modulated stacking using this strain-compensation technique is thus a useful way to expand the gain wavelength.
Algorithm of Marriage in Honey Bees Optimization Coperate with Linear Method
Authors: Yang Chen Guang , Liu Qiao Ge
Published: December 2013

Marriage in Honey Bees Optimization (MBO) is a new swarm-intelligence method, but it has the shortcomings of low speed and complex computation process. By changing the structure of MBO and utilizing a linear method to perform the local characteristic, we propose a new optimization algorithm. The global convergence characteristic of the proposed algorithm is proved by using the Markov Chain theory. And then some simulations are done on Traveling Salesman Problem (TSP) and several public evaluation functions. By comparing the proposed algorithm with MBO and Genetic Algorithm, simulation results show that the proposed algorithm has better convergence performance.
The Application of Data Fusion on Fault Diagnosis in Motor Coil
Authors: Chen Jie , Zhang Ke Ren , Zhu Wei Guo , Wang Ya , Zhao Jing
Published: December 2013

The coil is the important part of a motor. The traditional monitoring system of the coil can only act when a fault was found. A new fault diagnosis system in motor coil is discussed in the paper. We had built coil fault knowledge base by using data fusion. We had predicted and diagnosed the causes of coil fault quickly by inference rules.
Parametric Study of Air Flow Shape in Saddleback Double-Cladding Ventilated Roof on Input Velocity
Authors: Bartoš Tomáš , Pěnčík Jan
Published: December 2013

The study of air flow and its modelling is particularly focused on designing double-cladding roofs, which are recommended for buildings in wet conditions. Software ANSYS [, which uses CFD method, is used for the modelling. The primary issue concerning the design of ventilated double-cladding roofs is to select the optimum thickness of air cavity. The study shows that the shape of streamlines in the ventilated cavity of a double-cladding flat saddleback roof is not based on the input velocity. Based on the selected model, there is a blind spot in between 1.76 m and 4.23 m of the outer edge of the attic where air back flow occurs at the bottom surface of the upper roof deck which leads to poor ventilation of the ventilated cavity.
Simulation of the Influence of Air Preheat Combustion on the Temperature of Propane Turbulent Flame Using Probability Density Function Approach and Eddy Dissipation Model
Authors: Elwina  , Yunardi  , Bindar Yazid , Syukran
Published: December 2013

This paper presents results obtained from the application of a computational fluid dynamics (CFD) code Fluent 6.3 to modelling of temperature in propane flames with air preheat. The study focuses on investigating the effect of air preheat temperature on the temperature of the flame. A standard k-ε turbulence model in combination with the Probability Density Function (PDF) model for Non Premix Combustion model and Eddy Dissipation Model (EDM) are utilized to represent the flow and temperature fields of the flame being investigated, respectively. The results of calculations are compared with experimental data of propane flame taken from literature. The results of the study showed that the combination of the standard k-ε turbulence model and PDF model is more capable of producing reasonable predictions of temperature, particularly in axial profile and rich fuel area of all two flames compared with those of EDM model. Both experimental works and numerical simulation showed that increasing the temperature of the combustion air significantly increases the flame temperature.
Study of Phase Formation Processes in a Three-Component System of Diopside, Porcelain, Alumina
Authors: Pogrebenkov Valeriy M. , Kostikov Kirill S.
Published: December 2013

This article presents the study of phase formation at nonductile component interacting (diopside, alumina and pre-synthesized porcelain). Technical ceramic compositions with improved physical and mechanical properties are developed on the basis of these components. A theoretical research has been conducted, as a result of which a triple forecasting diagram is built in the system of diopside - alumina - porcelain. The diagram reflects 10 main areas with a major crystalline phase for the composition. Theoretical investigations are proved out by experimental data.
Study of Products of Electrical Explosion of Iron Wires in Argon-Oxygen Mixture
Authors: Pustovalov A.V.
Published: December 2013

Results of the study of characteristics of iron nanopowders obtained by electrical explosion of wires in argon and argon-oxygen media are presented. It was found that adding oxygen at a rate of 0.02 gO2/gFe allows to obtain iron powders resistant to fast air oxidation. The increasing rate of oxygen addition leads to the formation of γ-Fe2O3
Complex Catalysts for Direct Synthesis of Dimethyl Ether From Synthesis Gas. Part II. The Interaction of the Process Reactants and Products with the Catalyst Surfaces
Authors: Kosova Natalia I. , Kurzina Irina A. , Kurina Larisa N.
Published: December 2013

The mechanism of the Н2, СО, СО2, СН3ОН, (CH3)2O interaction with the surfaces of CuO/ZnO/Al2O3and γ-Al2O3was investigated using temperature-programmed desorption method with mass spectrometry detection. It was shown that desorption of the main process components takes place in the temperature range between 373 and 673 K, which corresponds to the temperature range for catalytic studies. Methanol dehydration takes place over the surface of γ-Al2O3catalyst with formation of dimethyl ether at Тmax= 553 К, which is the optimal temperature for synthesis of dimethyl ether from CO and H2over industrial catalysts with layered loadings. The desorption energies of the gases were calculated.
High Physicochemical Persistence of Aluminum Nanoparticles in Synthetic Body Fluids
Authors: Karepina Elizaveta , Godymchuk Anna Yu. , Kuznetsov Denis V. , Gusev Alexander A.
Published: December 2013

When nanoparticles get into a living body, they interact with body fluids. This study shows high physicochemical persistence of electroexplosive aluminum nanoparticles in physiological solutions simulating body fluids: Artificial Sweat (ASw), Simulated Saliva (SS), Simulated Gastric Fluid (SGF), and Artificial Alveolar Fluid (AAF). It has been demonstrated that after 14 days of exposure in ASw SS SGF AAF solutions, the average size of initial 90 nm nanoparticles became 90 100 230 90 nm, and the average size of initial 5 μm agglomerates became 1.6 0.9 1.0 3.0 μm, respectively. According to s SEM data, the exposed particles retained their spherical shape. With the help of the X-ray phase analysis it was shown that the oxide/hydroxide phase content in nanoparticles did not increase. It has been concluded that highly-reactive aluminum nanoparticles are capable to retain their phase composition, dispersion, and morphology in synthetic body fluids.
Nonwoven Polylactide Scaffolds Obtained by Solution Blow Spinning and the In Vitro Degradation Dynamics
Authors: Tverdokhlebov Sergey Ivanovich , Stankevich Ksenia , Bolbasov Evgeny N. , Khlusov Igor , Kulagina Irina , Zaitsev Konstantin
Published: December 2013

The solution blow spinning is presented as a method of obtaining tissue engineering scaffolds. The different forming modes were used and the optimum experimental conditions were found. It is shown that nonwoven polylactide scaffolds with required surface morphology can be obtained. These samples were studied in case of biodegradation in simulation body fluid. It was found that during scaffold dissolution the pH of the solution changes insignificantly (6.85) despite the exponential increase of the monomers of lactic acid. The calcium and phosphorus ion exchange between the scaffold and solution was observed in the surface and bulk of the material what makes possible to use scaffolds for regenerative medicine.
Structural State, Phase Composition and Mechanical Properties of Wear-Resistant Cast Iron Modified by Ultrafine Powders
Authors: Zykova Anna P. , Kurzina Irina , Lychagin Dmitry V. , Chumaevsky Andrey V. , Kachaev Artem A. , Bataev Vladimir Andreevich
Published: December 2013

The paper explores the effect of a modifier based on ultrafine powders of refractory metal oxides on the change of structural state, phase composition and mechanical properties of cast iron of ИЧХ28Н2 (Russian grade). It was shown that the modifier added to the melt does not change the phase composition of ferrite-austenitic matrix and carbides and is not carbide-forming. Material microstructure changes only due to the presence of a large amount of crystallization nuclei during the casting cooling. It was established that the modification increases the ultimate stress limit by 53%, plasticity by 10.7%, corrosion resistance by 15%, and leads to the reduction of friction factor and linear wear due to the decreasing of structural elements: carbide phase and austenitic-carbidic eutectic.
Structure and Properties of Leaded Tin Bronze under Different Crystallization Conditions
Authors: Martyushev Nikita , Semenkov Ilya V. , Petrenko Yuriy N.
Published: December 2013

The influence of crystallization conditions of leaded tin bronze on the obtained microstructure parameters is examined in the paper. Modification of crystallization conditions was realised by varying the cooling rate of the melt with preheating of the casting molds. Quantitative regularities of the influence of the cooling rate of bronze on its phase composition are presented. Data on mechanical properties of the material under investigation are also reported in the paper. It is demonstrated that high cooling rates (casting into mold at ambient temperature) enable obtaining higher mechanical properties in comparison with low cooling rates (casting into mold heated up to 800 °С).
Simulation Study of Dynamic Features during the Isothermal Relaxation Processes in Supercooled Liquid and Glassy Pb
Authors: Zhou Li Li , Zheng Xuan , Luo Hui
Published: December 2013

The molecular dynamics simulations on the isothermal relaxation properties of supercooled liquid and glassy Pb have been performed. The calculated diffusion constant of Pb is well agreed with the experimental result. Results indicate that the relaxations of supercooled and glassy Pb present more and more pronounced heterogeneity with decreasing temperature. The appearance of the second plateau of mean square displacement (MSD) and the non-zero plateau of Non-Gaussian parameter (NGP) is corresponding to the rest of structure rearrangement.
Influences of Fe Doping on the Electronic Structure of Mg(0001) Surface and Hydrogenation Mechanism in Fe-Doped Mg(0001) Surface
Authors: Wang Zhi Wen , Guo Xin Jun , Zhang Hong Xia , Li Li
Published: December 2013

First-principles calculations within the density functional theory (DFT) have been carried out to study the interaction of hydrogen molecule with Fe-doped Mg (0001) surfaces. First we have calculated the stability of the Fe atom on the Mg surface, On the basis of the energetic criteria, Fe atom prefer to substitute one of the Mg atoms from the second layer. In the second step, we have studied the interaction between hydrogen molecule and the Fe-doped Mg (0001) surface. The results show that for Fe atoms doped Mg (0001) surface in the second layer, enhances the chemisorption interaction between H2 molecule and Fe atom, but also benefits H atom diffusion into Mg bulk with relatively more diffusion paths compared with that of clean Mg surface. Charge density difference plots provided some ideas about why certain alloying elements on the surface reduce the energy barrier of H2 molecule dissociation on Fe-doped Mg (0001) surface. We can see that Fe as catalyst for the hydrogenation/dehydrogenation of Mg alloy samples and provide more dissociation path for H2 molecule and diffusion paths for H atom, The present results not only beneficial for clarify the experimentally observed fast hydrogenation kinetics for Fe-capped Mg materials but also help to design new types of hydrogen storage materials for practical applications in the auto industry.
The Hydrothermal Synthesis of BaTiO3 Nanotubes Arrays with Good Electrical Property
Authors: Yang Jie , Wang Li Jie , Deng Xiang Yun , Shao Jian , Sun Yang Shan , Hou Xing Gang
Published: December 2013

Barium titanate nanotubes arrays were synthetized by in-suit hydrothermal method using TiO2 nanotubes as both template and reactant in titanium substrate. Highly ordered nanotubes arrays and the spacing between nanotubes are apparent. XRD indicates that the samples have excellent crystallization and perovskite structure. Typical ferroelectric hysteresis loop of as-formed barium titanate nanotubes arrays with remanent polarization and coercive field are 6.72 and 48.7kV/cm.
Characterization, Photoluminescence and Magnetic Properties of SiC Nanowires Synthesized with Nickel Catalyst via Microwave Heating
Authors: Liu Song , Huang Shan , Wang Ji Gang
Published: December 2013

Large scale SiC nanowires were synthesized through a rapid and low-cost microwave heating method. Silicon, silica, graphite and nickel powders were used as raw materials and catalyst, respectively, and no inert protective gas was employed during the preparation. The microstructures of the products were comprehensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). Results showed that the nanowires have lengths of several dozens of micrometers and diameters of 50nm approximately. The growth of them was governed by vapor-liquid-solid (VLS) growth mechanism. In addition, the photoluminescence (PL) and magnetic properties of the products were subsequently investigated by fluorescent photometer and vibrating sample magnetometer (VSM). The PL spectrum, employing a Xe laser (240 nm) as an excitation source, shows an emission band centered at about 390 nm, indicating that the obtained SiC nanowires possess excellent optical property. The hysteresis loop shows big magnetic saturation (Ms) of 0.96 emu/g and small coercivity (Hc) of 37.92 Oe. So, the obtained SiC nanowires can be characterized as typical soft magnetic material, and the improvement of magnetic properties may be attributed to the existence of Ni2Si phase in the SiC nanowires.
Temperature Comparison of External Thermal Insulation Wall Using Foam Glass under Thermal and Humidity Effect
Authors: Luo Yi Ying , Wu Xiao Yan , Xiang Yi , Niu Zhi Rong
Published: December 2013

Experiments are performed aiming at the hot summer and cold winter area climate characteristics. The BWNH-3021 type weather-resistant testing apparatus is used to achieve performances of foam glass exterior thermal insulation walls. Real-time temperatures of each functional layer are tested under hot rain cycle effect. The temperature curves are plotted to make comparisons. When the environment temperature rises about 60°C, the temperatures of primary wall will rise only 8.20°C9.30°C each in 1#2# testing wall. When cold water is suddenly sprayed, the environment temperature will fall about 51°C. Then the temperatures of primary wall will fall only 4.00°C4.20°C each in 1#2# testing wall. It shows the good thermal insulating property of foam glass exterior thermal insulation wall. The environment temperature fluctuation can also be eliminated significantly. Attenuation coefficients of different thermal insulation walls are calculated. The maximum attenuation coefficients are present when temperature is rising. The coefficients of 1#2# testing wall are 15.00 and 4.60 separately. And the delay-times of two walls are 148min133min respectively. Both of the total attenuation coefficient and delay-time of 1# wall are greater than those of 2# wall. It indicates that a thicker layer makes the temperature wave decays more and takes longer time to delay. It proved that a thicker external thermal insulation structural layer contributes to the resistance of temperature fluctuation and thermal stability.
Study on Preparation and Interlayer Ion State of Fe/Ni Pillared Motmorillonite
Authors: Zhu Xi Xi , Wang Li , Gao Wei Jia
Published: December 2013

Fe/Ni pillared montmorillonite is synthesized by precursor method. Organic pillared montmorillonite is prepared first by ion exchange with Cetyltrimethyl ammonium bromide (CTAB) using Ca-montmorillonite as raw material after pretreatment. Fe/Ni pillaring agents is prepared by copolymerization method. Then the Fe/Ni pillared montmorillonite is synthesized through ion exchanging and calcining. The structural changes and thermostability were studied through X-ray diffraction, X-ray fluorescence analysis, infrared spectroscopy and TG. analysis. The concentration of CTAB has a significant effect on interlayer space height of momtmorillonite, which can reach 3.9756nm when the concentration is 3CEC. The interlayer space height of Fe/Ni pillared montmorillonite can reach 2.4001nm when when n (Fe3+):n (Ni2+) is equal to 7:3, and it remains 1.7876nm after calcined at 400°C for 2h. This indicates that thermostability is good. Pillaring agents embedded into montmorillonite interlayer, and bonding reaction happened between the skeleton of montmorillonite ([Si4O10]n) and pillaring agents, which forms the bonding of Si-M (Fe or Ni).
Effects of RbI on the Optical and Mechanical Properties of Ge23Se67Sb10 Glass
Authors: Chang Fang E , Zhang Yan Yan , Xu Jun Feng , Zhu Man , Jian Zeng Yun
Published: December 2013

(100-x)Ge23Se67Sb10-xRbI glasses were prepared by the melting technique. The structures and properties were investigated by using SEM, XRD, DSC, FTIR and Vickers hardness tester. It is found that, with increasing x, the glass-forming ability and the infrared transmittance of (100-x)Ge23Se67Sb10-xRbI samples decrease, the thermal stability and the fracture toughness increase, the Vickers hardness increases first and then decreases. When the content of RbI is 1%, the hardness reaches the maximum value 1985 MPa, at this point, the fracture toughness reaches 10.41 MPamm1/2.
A Formaldehyde Gas Sensor Based on Zinc Doped Lanthanum Ferrite
Authors: Zhang Jin , Zhang Yu Min , Hu Chang Yi , Zhu Zhong Qi , Liu Qing Ju
Published: December 2013

The gas-sensing properties of zinc doped lanthanum ferrite (Zn-LaFeO3) compounds for formaldehyde were investigated in this paper. Zn-LaFeO3 powders were prepared using sol-gel method combined with microwave chemical synthesis. The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formaldehyde gas-sensing characteristics for the sample were examined. The experimental results indicate that the sensor based on the sample Zn-LaFeO3 shows excellent gas-sensing properties to formaldehyde gas. At the optimal operating temperature of 250°C, the sensitivity of the sensor based on LaFe0.7Zn0.3O3 to 100ppm formaldehyde is 38, while to other test gases, the sensitivity is all lower than 20. The response and recovery times for the sample to formaldehyde gas are 100s and 100s, respectively.
Effects of Deposit Time on Combustion Flame Deposition of Carbon Coatings on the Surface of Cemented Carbide
Authors: Tang De Weng , Kuang Tong Chun , Zhao Rui Lan
Published: December 2013

At present, most of the researches on carbide surface modification are focused on the method of chemical vapor deposition and physical vapor deposition in order to enhance its wear resistance and surface hardness. In this paper, C2H2 and O2 of flame are used to deposit carbon coatings on YG 16 cemented carbide surface. The influence of deposition time have been investigated with the method of XRD, SEM. Carbon coatings structure, quality and Cross sectional microstructures of carbon coating was analyzed.The experimental result show that after different deposition time, the typical spherical diamond\nanometer carbon tube and diamond-graphite-no crystal carbon coatings have been formed on the surface of cemented carbide.
Inhibition of Electrical Tree Initiation inside High-Voltage Cross-Linked Polyethylene Cable with Nonlinear Shielding Layer
Authors: Li Chang Ming , Zhang Guang Xiang , Li Chun Yang , Han Bao Zhong
Published: December 2013

Electrical tree aging is one of the leading factors causing degradation and breakdown of insulation performance of high-voltage cross-linked polyethylene (XLPE) cable. A lot of attention has been paid to inhibiting electric tree initiation and propagation inside high-voltage cable. In this study, insulation composites with nonlinear electrical conductivity are prepared. Experimental results show that these composites are helpful for enhancing the apparent breakdown electric field strength of XLPE in the pole electrode system. A kind of high-voltage XLPE insulated cable with new structure is designed by using these composites as nonlinear shielding layer. Numerical simulation results indicate that nonlinear shielding layer can obviously improve the distribution of electrical field at the defect of insulation surface of high-voltage XLPE cable, and decrease the maximum electrical field strength at the defect. This new structure is potential for effectively inhibiting electrical tree initiation inside high-voltage XLPE insulation cable, thus increasing life span and operational reliability of the cable.
Classification of High Quality Carbon Steel Based on BP Neural Network
Authors: Liu Lan Lan , Zhang Tao Hong , Xie Yong Hong , Li Li , Zhang De Zheng , Wulamu Aziguli
Published: December 2013

Now carbon steel is used in the engineering aspects and it is the oldest and the largest amount of basic materials. How to determine whether they are high-quality carbon steel In this paper the standard data of high quality carbon steel by using the classical BP neural network algorithm is researched. Then it is simulated and predicted. The final comprehensive evaluation and analysis show that the neural network model can be used to decide whether it is a high quality carbon steel. Further, it has a good practical application value for utilizing high-quality carbon steel rationally.
Process Study of Atomic Layer Deposition Al2O3 in Industry Application for Solar Cells
Authors: Qiu Hong Bo , Li Hui Qi , Liu Bang Wu , Xia Yang
Published: December 2013

The rear surface of multi-silicon has been passivated by Atomic Layer Deposition (ALD) Al2O3 and Plasma Enhanced Chemical Vapor Deposition (PECVD) SiNx. The results of the effective lifetime of the silicon before and after firing show that the thickness of Al2O3 thin films has a significant effect on the passivation quality. The effective lifetime of the silicon can reach up to 40.64μs and show a better passvation quality when the thickness of Al2O3 film is 18nm. Moreover, the impact of spacing of the laser opening-line contact on open-circuit voltage and fill-factor has been furthermore investigated. The cells have a better performance when the spacing of the opening-line is 1.2mm. The result of the local topography of the opening-line contact tested by Scanning Electron Microscopy (SEM) shows that the existing of the void in the interface between Al and Si is the main reason for the bad performance of the cells.
Study of Catalytic Pyrolysis of Chlorella with γ-Al2O3 Catalyst
Authors: Liu Juan , Li Xia , Guo Qing Jie
Published: December 2013

Chlorella samples were pyrolysed in a fixed bed reactor with γ-Al2O3 or ZSM-5 molecular sieve catalyst at 600°C. Liquid oil samples was collected from pyrolysis experiments in a condenser and characterized for water content, kinematic viscosity and heating value. In the presence of catalysts , gas yield decreased and liquid yield increased when compared with non-catalytic pyrolysis at the same temperatures. Moreover, pyrolysis oil from catalytic with γ-Al2O3 runs carries lower water content and lower viscosity and higher heating value. Comparison of two catalytic products, the results were showed that γ-Al2O3 has a higher activity than that of ZSM-5 molecular sieve. The acidity distribution in these samples has been measured by t.p.d, of ammonia, the γ-Al2O3 shows a lower acidity. The γ-Al2O3 catalyst shows promise for production of high-quality bio-oil from algae via the catalytic pyrolysis.
Study on Positron Annihilation Lifetime of Amorphous Alloy Fe73.5Cu1Nb3Si13.5B9 by Magnetic Pulse Treated
Authors: Zhang Yan Hui , Chao Yue Sheng , Gu Yue , Hao Xiao Peng , Wang Bao Yi , Zhang Lin
Published: December 2013

The effect of magnetic pulse treatments on Fe73.5Cu1Nb3Si13.5B9 amorphous alloy prepared by melt-spun technique is investigated. The structural defects of the treated specimens are investigated by position annihilation lifetime spectra. The results show that amorphous alloy Fe73.5Cu1Nb3Si13.5B9 have two kinds of free volume. One is Bernal vacancy-like which is characterized by less than an atomic volume, Another is void-like defect. Under the applied pulsed magnetic field, the annihilation lifetime and the relative intensity of treated specimens is decrease because the crystallization phase separate out from the amorphous matrix. The relative intensity I2 is increase because the larger free volumes appear at grain boundary of Cu and Nb enrichment area.
Ferromagnetic Characteristics of Bulk Fe63Co7Nb4Zr6B19Si1 Metallic Glass
Authors: Xu Min , Wang Qun Jiao
Published: December 2013

By copper mold casting, a bulk Fe63Co7Nb4Zr6B19Si1 metallic glass was synthesized in the diameter of 2mm. The Fe-based amorphous alloy exhibits soft ferromagnetic characteristics with a saturation magnetization of 77Am2/kg and a saturated magnetostriction of 25.4×10-6. The saturation magnetization is reduced while the coercive force is slightly lowered by annealing treatment below the crystallization temperature. The devitrification gives rise to a remarkable enhancement both in saturation magnetization and coercive force.
Post-Processing of Chitosan Based Nanofibers Prepared by Electrospinning
Authors: Sun Kang , Ge Yuan Xin , Li Zhong Hui , Zhang Xiao Lin
Published: December 2013

Recently, electrospinning of nanofibers based on chitosan has been widely studied and numerous chitosan based nanofibers have been prepared, for the enormous possibilities of applications in various areas such as filtration, enzyme immobilization, tissue engineering, wound dressing, drug delivery, and catalysis. Because most of the chitosan based nanofibers are soluble in aqueous solutions and the other properties such as mechanical properties are not suitable for the further applications. It is necessary to improve the properties of chitosan based nanofibers. Various post-processing has been done to the chitosan based nanofibers and many post-processing products have emerged. This article discusses the post-processing of the chitosan based nanofibers involving methods, mechanisms, changes of nanofiber properties, and applications of the post-processing products in details. The post-processing is divided into alkali treatment, crosslinking, and functionalizing.
Synthesis of Super Absorbent Resin from Starch/Bentonite
Authors: Wang Rui Jie , Yang Lian Wei , Zhang Han Dan , Geng Tie Jun
Published: December 2013

The compound super absorbent resin was synthesized by starch, bentonite, acrylic acid and acrylamide, using microwave irradiation. Some key factors affecting the solution absorbency of the polymer such as the amount of bentonite, acrylamide, initiator and cross-linking agent have been discussed. The results showed that the optimal reaction conditions of cross-linking agent, initiator, neutralization degree, bentonite, phosphate starch are 0.045%, 0.32%, 70%, 10%, 3% when the weight ratio of acrylic acid and acrylamide was 2:1, the microwave power was 800W, the radiation time was 15min. Under the conditions, the pure water absorption rate of super absorbent resin was up to 796g/g. when the weight ratio of acrylic acid and acrylamide was 1:1, the absorption rate of 0.9% NaCl was 95g/g.
Dielectrophoresis Response and Manipulation of Silica and its Application to Micro/Nanosensors
Authors: Lan Bi Hao , Zhang Lu , Chen Hui Ying , Tan Ling Yu , Li Hua , Feng Li Li , Hong Xiao Ye
Published: December 2013

In this paper, silica microspheres and several novel μm scale DEP (dielectrophoresis) micro electrode array chips were prepared. A DEP experimental system was assembled to investigate the the DEP response of silica microspheres and micrometer particles. The effects of pattern of electrodes and frequency of AC field on the manipulation of silica microspheres were analyzed. The results showed that silica microspheres were manipulated by negative DEP (nDEP) in all types of electrodes, the position of silica microspheres in the electrodes changed when the frequency was changed and the phenomenon of nDEP was more obvious at higher frequency. A gas sensor was fabricated by dielectrophoretically assembling SiO2 micrometer particles. The sensor showed good response to SO2 and NH3 gas. The measurement results confirmed DEP could be a quicker method for constructing gas sensor.
Charge Injection in Regioregular Poly-(3-Hexythiophene) Organic Field-Effect Transistors with Different Metal Electrodes
Authors: Zhang Rui Rui , Lin Shi Wei , Liao Jian Jun
Published: December 2013

Here we report on regioregular poly-(3-hexythiophene) (P3HT) organic field-effect transistors (OFETs) with various metal electrodes: pristine Au, pristine Cr, and Cr/Au. Compared to the performance of OFETs using different electrodes, the OFETs with Au electrode have better mobility (μ = 0.0090 cm2/Vs) and larger current at the same source-drain voltage and gate voltage. The enhancement of the device performance with Au electrode can be attributed to a small contact resistance and a small barrier height to P3HT for hole carrier injection.
Synthesis of Water-Soluble Fluorescent Carbon Dots from a One-Step Hydrothermal Method with Potato
Authors: Sun Ying Xiang , He Zhi Wei , Sun Xiang Bao , Zhao Zeng Dian
Published: December 2013

Water-soluble fluorescent carbon dots (CDs) have been synthesized in one step by hydrothermal treatment of potato. Effects of the hydrothermal treatment time, temperature, potato additive amount and pH on the light emissions of the CDs were also studied. HRTEM images of the CDs showed spherical particles with fairly uniform diameter of approximate 2~3 nm, which also dispersed excellently in water. The characteristic absorption peak of CDs appeared at about 280 nm and exhibits a strong bright blue light emission with a high quantum yield (14.2%). The mechanism of the fluorescent emission from CDs was proposed. Moreover, some highly fluorescent CDs were also prepared with other vegetables under the same condition.
Transport Properties of Two-Dimensional Electron Gas in Cubic AlGaN/GaN Heterostructures
Authors: Feng Qian , Shi Peng , Zhao Jie , Du Kai , Li Yu Kun , Feng Qing , Hao Yue
Published: December 2013

We presented a theoretical study of the dependence of 2DEG mobility on temperature, barrier thickness, Al content, donor concentration to reveal the internal physics of 2DEG mobility in cubic AlGaN/GaNheterostructures. The 2DEG mobility is modeled as a combined effect of the scattering mechanisms including acoustic phonons, ionized impurity, dislocation, alloy disorder and interface roughness scattering.The variation of mobility results mainly from the change of 2DEG density and temperature. It reveals the dominant scattering mechanismsare dislocation and alloy disorder scattering atlow temperature.Acoustic phonons scattering becomes the major limit at 300k. Impurity scattering plays the key role when donor density rises. We find a maximum mobility with a structure of 25% Al content and 4-5nm barrier thickness.