bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Sand Ratio on the Fluidity Properties of SCC in CRTS III Type Track System
Authors: Gu Hai Peng , Li Gu Hua , Zeng Xiao Hui , Cheng Jian Qiang
Published: December 2012

In order to prepare SCC (self-compacting concrete) which is used as the packing layer in CRTS III type track system this paper primary researched the influence of sand ratio on its performance through experiments of the design of mix proportion. Test results show that when sand ratio is too small, the fluidity of SCC will be bad and the concrete will generate segregation and weeping. If sand ratio is too great, the workability of SCC will not be good either, but segregation will not occur again. The optimum range of sand ratio is 0.56 to 0.58 in this paper, while the range proposed by China Academy of Railway Sciences is 0.50 to 0.55.
The Application of Ground Penetrating Radar in the Karst Detection of Tunnel Bottom
Authors: Yang Cheng Zhong , Chen Yi Lin , Wang Yan Jun , Fang Chao
Published: December 2012

In order to ascertain the karst development status under tunnel arch, take the appropriate engineering measures according to the different karst state and ensure the tunnel structure safety. Based on the difference electric properties of electromagnetic wave in the different media, for karst development features of large dam tunnel area, applying geological radar, the karst development status under the tunnel arch dam bottom was detected. Geophysical interpretation show the karst of the rock under arch dam bottom develops well and exist karst structure. The tunnel is not safe. In construction, engineering measures such as excavation and backfill are taken. The results show that: the geological radar is a good resolution for karst development situation; the engineering measures adopted are effective.
The Study on Mechanical Properties and Microstructure of Cement Paste with Nano-TiO2
Authors: Feng Li Chao , Gong Chun Wei , Wu Yun Peng , Feng De Cheng , Xie Ning
Published: December 2012

Cement paste with addition of a small amount of (0.9wt%) nano-TiO2 were prepared. Flexural strength and compressive strength testing results showed that by adding a small amount of nano TiO2 with good dispersion, the 28-day flexural strength and compressive strength of cement paste modified by nano-TiO2 was increased by 16.12%, and 14.15%, respectively.
Surface Roughness Extraction by Gibbs Random Fields of Laser Speckle Pattern Texture
Authors: Yang Lei , Lu Rong Sheng , Liu Zhi Jian , Lei Li Qiao
Published: December 2012

Based on computer texture analysis methods, the relationships between laser speckle texture features of grinding surfaces and surface roughness are investigated. The laser speckle texture pictures of different surface roughness are acquired by a simple equipment which consists of a digital camera and a diode laser. The texture method based on Gibbs Random Fields model is used to analyze laser speckle patterns. Gibbs texture features with the second-order neighborhood are extracted. The experiment results display that the surface roughness information included in the laser speckle texture pictures is monotonous withβ2~β5 Gibbs texture features. For comparing, normalized texture features has been done. This method can extract object’s surface roughness information which is the same material and machined by the same method through calibrating beforehand.
Micro-Drop Mixer Driven by Standing Surface Acoustic Waves (SSAW)
Authors: Miao Bao Gang , Wang Chao Hui , Zheng Teng Fei , Zhang Qun Ming , Jiang Zhuang De
Published: December 2012

High-frequency surface acoustic waves (SAW) were generated and transmitted along single-crystal lithium niobate (LiNbO3). The standing surface waves (SSAW) formed between two parallel inter-digital transducers (IDTs) on a LiNbO3 substrate, were employed to drive the micro-drop mixer. An SSAW device was designed, micro-machined and tested. When an AC signal with the frequency of 61.4MHz was applied to the IDTs, vortex appeared in the drop consisted of two incompatible liquid (ink and glycerol). The evolution of the vortex was recorded in this work. With the evolution of the vortex, mixing process of two incompatible liquid has been demonstrated. The mixer is of significant relevance for many bio-technological applications and in particular for lab-on-chip. While the experimental liquids were mutually incompatible, the ink could only be divided into smaller drops.
Experiment of Control Blasting with Water Jets Slotting
Authors: Wang Xiao Chuan , Kang Yong , Yang Xiao Feng
Published: December 2012

Use similar material and system of caustics to simulate the characteristics of fissure distribution and dynamic vacation regulations of fissure generation and expansion, whose fissure is made by plexiglass jet slotting and blasting under the condition of explosion. We have analyzed and compared the expanding length and velocity of main fissure’s point and dynamic intensity factors between the holes of ordinary blasting and water-jet slotting; and discussed the dynamic effects of slotting blasting. The study shows that, with the same explosive quantity, the fissures of common blasting hole distribute randomly around the hole with large quantity but with short fissures and the caustic spots have small diameter and distribute with fissures; while the fissures of jet slotting hole blasting are longer and distribute mainly along the fissure’s direction, the caustic spots are clear and mainly concentrate among the fissures with lager diameter. That is to say, the jet cutting blasting energy concentration can improve the effect of rock damage. The existence of jet seam has a guidance quality to rock breakage. Main fissures take place and expand from the direction of slotting seam while the distension along other directions is heavily weakened in the process.
Design of Ultrasonic Guided Wave Excitation Signal Generator for Rotating Shafts
Authors: Wang Xiao Yu , Yang Yan Yan , Wang Dao Shun
Published: December 2012

Ultrasonic guided wave detection technology has mangy special characteristics. It can spread very far along the components in the distance and it can throughout the whole thickness of components, so we can make use of ultrasonic guided wave to test component of internal and surface defects. The rotating shafts are the organizations widely used in the modern production but they are very easy to be dangerous faults. If we can realize the rotating shaft in time, it can reduce the danger. It is significant to design an affordable generator which produces signals to drive magnetostrictive probe that produces ultrasonic guided wave. In this paper, we choose the torsional wave as example to design signal generator. We will introduce the way to select the appropriate guided wave mode and frequency of excitation. Design signal generator with ATmega32, AD9851 and DAC0832.
Study on Contact Strengths of Thick-Walled Cellular Solids with Irregular Pores Structures
Authors: Xie Fang , Liu Zuo Min
Published: December 2012

For improving contact strength of the thick-walled cellular solid with irregular pores structures, which is used in high temperature self-compensating lubricating environment, a concept of relative porosity ratio αi was proposed to describe the proportion of the porosity φi of the each shape pores in the materials to the total porosity φ of the materials. The results show that the characteristic value of αi, the distribute radius and regularity as well as the orientation of pores affected the contact strength strongly. The cracks phenomenon of the materials was also observed by experiments.
The Role of Na and Mg Doping on the Electronic Conductivity of LiFePO4 : First-Principles Investigations
Authors: Wu Jing , Xu Gui Gui , Lin Ying Bin , Huang Zhi Gao
Published: December 2012

The effects of Na and Mg doped Li site for Li1-xMxFePO4 have been studied using first-principles within GGA+U. Elastic band method has been used to calculate the activation energy for Li diffusion. The calculated results mean that, the band gaps of the Na and Mg doped Li1-xMxFePO4 are both narrow than that of the un-doped. Especially Mg dopant gives rise to much narrow gap, which is attributed to the appearance of impurity level in the forbidden band of un-doped LiFePO4. The calculated activation energies for LiFePO4, Li0.875Na0.125Subscript textFePO4, and Li0.875Mg0.125FePO4 are 0.33eV, 0.31 eV, and 0.15 eV, respectively. From the calculated results of band gap and activation energy, we can find that Mg dopant will benefit for the hopping of electrons and the improvement of the electronic conductivity for LiFePO4.
Asymptotic Analysis of Second-Order Boundary Layer Correctors for Composite Plate with 3-D Small Periodic Configuration
Authors: Wang Zi Qiang , Cui Jun Zhi
Published: December 2012

We consider a second order two scale (SOTS) approximate solution to the 3-D small periodic configuration composite plate. Classical two scale approximation yields a O( ) error in whole domain. We construct here a second-order mixed boundary layers corrections for the rectangle composite plate. Based on the boundary layers correctors, we prove that the optimal convergence order of the approximate solution to composite plate is O( ) in H1-norm. The numerical results for predicting the elastic parameters and the displacement and strains to composite plate made of 3-D 4-direction braided materials are demonstrated. Those show that the two scale approximation solution can capture the macroscopic phenomena caused from 3-D microcosmic configuration well.
A Review of Contact Sensors Used for Monitoring Malodorous Gas in Animal Facilities
Authors: Zhang Shi Rui , Wang Ji Hua , Dong Da Ming , Zheng Wen Gang , Zhao Xian De
Published: December 2012

Animal facilities produce large amounts of harmful gases, and many of them have a pungent odor such as ammonia, hydrogen sulfide and other malodorous gases. The malodorous gases generated by animal house not only affect the health of people and livestock but also pollute the air. The detection of the malodorous gases can effectively improve efficiency of livestock production and reduce environmental pollution. More and more gas detection method is applied to the detection of the malodorous gases generated by animal house. This paper summarizes contact sensors for monitoring of malodorous gases in animal house recently, including semiconductor sensors electrochemical sensors and electronic nose. The basic principle and the characteristics of these methods were illustrated and the applications on the detection of malodorous gases in animal house were described. Meanwhile, the researches of malodorous gases monitoring for livestock production applied contact sensors were listed. The status quo and future development of the contact sensors for malodorous gases generated by animal house were summarized.
Embedded Supervisal System of Geological Prospecting Based on AMF Protocol
Authors: Li Peng , Fu Yuan Ting
Published: December 2012

This article analyzes the methods for project supervision in the geological prospecting industry at present, and proposes an embedded supervisal system of geological prospecting designed with the mobile terminals as an assistant supervisal measure, to increase the efficiency of project supervision. Supervisal indicators are categorized and studied, and an indicator system for the geological prospecting is introduced. The method for implementing AMF protocol based system is presented to solve huge data filling in the field.
A New Small-World Neural Network with its Performance on Fault Tolerance
Authors: Li Xiao Hu , Xu Feng , Zhang Jin Hua , Wang Su Nan
Published: December 2012

Many artificial neural networks are the simple simulation of brain neural network’s architecture and function. However, how to rebuild new artificial neural network which architecture is similar to biological neural networks is worth studying. In this study, a new multilayer feedforward small-world neural network is presented using the results form research on complex network. Firstly, a new multilayer feedforward small-world neural network which relies on the rewiring probability heavily is built up on the basis of the construction ideology of Watts-Strogatz networks model and community structure. Secondly, fault tolerance is employed in investigating the performances of new small-world neural network. When the network with connection fault or neuron damage is used to test the fault tolerance performance under different rewiring probability, simulation results show that the fault tolerance capability of small-world neural network outmatches that of the same scale regular network when the fault probability is more than 40%, while random network has the best fault tolerance capability.
Ring-Space Array Torque Measure System and Signal Singularity Detection
Authors: Wang Yuan Gan
Published: December 2012

Torque is the most important dynamic characteristics of the mechanically-driven system. In order to monitor the mechanical principal axis in real time, a new non-contact torque measurement system based on ring-space array sensor is proposed. This system can be used for the analysis of dynamic characteristics of the mechanical system’s axis under various loads and hard working environments. Singularity in the collected signals is most important with the mechanical system. Because of much noise was contained in collected signals, which always interferes the signal’s singularity detection. According to the different behaves of signal and noise under wavelet transform, a method with wavelet filtering and singularity detection combined is proposed. This method could realize two-dimension filtering reconstruction in both time and frequency domain, in which the singularity information in signal can be kept well while the noise will be filtered. The proposed method is suitable for singularity detection of signals under serious noise.
Research in Keyphrase Extraction
Authors: Wu Bing , Zhang Chen Yan
Published: December 2012

The purpose of this study is to review on keyphrase extraction research from science citation index expanded (SCI-EXPANED) database on web of science. The result indicates that the number of literature productions on this topic mainly distributes in recent 10 years, reaching climax in 2005 and then followed by 2010. The primary research development country is China. From the analysis result of document type, proceedings paper accounts for 50%. In general, the related research topics can be classified into keyphrase extraction for oriental language documents, English documents and bilingual documents. Hebrew documents and Chinese documents as oriental language documents have been the main objects for keyphrase extraction. Meanwhile keyphrase extraction for bilingual documents has been stressed on English and Arabic documents. Meanwhile recommendation is the focus for keyphrase extraction in English documents.
Hygrothermal Effect on Stiffness Reduction Modeling Damage Evolution in Cross-Ply Composite Laminates
Authors: Sahnoun M. , Ouinas D. , Benderdouche N. , Bouazza M. , Viña J.
Published: December 2012

An analytical model based on the displacement function of the opening of crack applied by Lundmark and Varna [26] in the internal layers to study the evolution of the decrease of stiffness in a laminate is investigated. The results of axial rigidity versus the crack density are presented for three composite materials. The influences of the temperature and moisture on the mechanical properties of composite material are highlighted. The micromechanical model of the laminates used in present study describes the degradation of the mechanical properties of composite material by the variation in the temperature and moisture. The hygrothermal effect is observed to be harmful for composite materials.
Multi-Fractal Nature of HS 300 Index and its Traded Volume
Authors: Zuo Shun Gen
Published: December 2012

A study of the multi-fractal nature of three time series related to the Hushen300 index, HS300, including daily closing prices, daily yield rates and daily traded volumes time series is presented. Multi-fractal Detrended Fluctuation Analysis (MFDFA) is used in the study. The results show that the three related time series are with strong persistence characters. By multi-fractal spectrum analysis, the width of the multi-fractal Spectra of traded volume series is to be found the biggest among the three. It means that the traded volumes series are most irregular.
Stability Analysis and Controller Design of Networked Control Systems with Packet Dropout
Authors: Sun Ye Guo
Published: December 2012

In this paper, the stability and stabilization problems of a class of networked control systems (NCSs) with bounded packet dropout are investigated. An iterative approach is proposed to model NCSs with bounded packet dropout as Markovian jump linear systems (MJLSs). The transition probabilities of MJLSs are partly unknown due to the complexity of network. The system under consideration is more general, which covers the systems with completely known and completely unknown transition probabilities as two special cases. Moreover, both sensor-to-controller and controller-to-actuator packet dropouts are considered simultaneously. The sufficient conditions for stochastic stability and stabilization of the underlying systems are derived via linear matrix inequalities (LMIs) formulation. Lastly, an illustrative example is given to demonstrate the effectiveness of the proposed results.
Finite-Time Control of Networked Control Systems with Bounded Packet Dropout
Authors: Xu Jin , Sun Ye Guo
Published: December 2012

In this paper, the finite-time boundedness and stabilization problems of a class of networked control systems (NCSs) with bounded packet dropout are investigated. The main results provided in the paper are sufficient conditions for finite-time boundedness and stability via state feedback. An iterative approach is proposed to model NCSs with bounded packet dropout as jump liner systems (JLSs). Based on Lyapunov stability theory and JLSs theory, the sufficient conditions for finite-time boundedness and stabilization of the underlying systems are derived via liner matrix inequalities (LMIs) formulation. Moreover, both sensor-to-controller and controller-to-actuator packet dropouts are considered simultaneously. Lastly, an illustrative example is given to demonstrate the effectiveness of the proposed results.
Command and Control System Executable Modeling Researching
Authors: Tang Xue Song , Meng Qing Hua , Dong Zhi Hong , Lou Da Guang
Published: December 2012

We proceed from the perspective of object-oriented analysis and design modeling, focusing on the model design of command and control automation system, using Colored Petri Net (CPN) to a command and control systems for dynamic design and simulation run. A method of mapping from UML product can be used for logical, behavioral and performance aspects of architecture evaluation methods of CPN executable models is proposed. We first descript the command and control system for UML modeling generally, and then elaborate the process from UML products are mapped to the CPN build executable model of the command and control system.
Effect of Fiber Orientation on the Critical Buckling Load of Symmetric Composite Laminated Plates
Authors: Hamani N. , Ouinas D. , Taghezout N. , Sahnoun M. , Viña J.
Published: December 2012

In this study, a buckling analysis is performed on rectangular composite plates with single and double circular notch using the finite element method. Laminated plates of carbon/bismaleimde (IM7/5250-4) are ordered symmetrically as follows [(θ/-θ)2]S. The buckling strength of symmetric laminated plates subjected to uniaxial compression is highlighted as a function of the fibers orientations. The results show that whatever the notch radius, the buckling load is almost stable. Increasing the degree of anisotropy significantly improves critical buckling load.
Research on Accounts Receivable Control Problem in Stages
Authors: Song Yuan Yuan
Published: December 2012

Businesses accounts receivable has the function of expanding sales and inventory reduction, but will also increase their opportunity costs, bad debt costs and management costs in the meantime. In order to better resolve the unity of opposites problem, this article presents the phases of accounts receivable control problems, mainly reflected in three aspects: prior management and control, concurrent financial control and feedback control afterwards.
Design and Performance Analysis Based on High-Speed Switching Valve of Magnetorheological Plug-Mounted
Authors: Liu Yun Han , Wu Zhang Yong , Wang Xian , Duan Zhen Hua , Gao Xiao Yan , Qu Jin Tao
Published: December 2012

Based on the rheological mechanism of magnetorheological fluid，we can design a kind of magnetorheological high-speed on-off valves,which used the Plug-in structure.It is shows that， through the static and dynamic performance analysis of the valves，the magnetorheological high-speed on-off valves not only has the good static, dynamic characteristics, compare to magnetorheological plug-mounted speed switch valve with traditional hydraulic, and with high speed of response, high stability, etc . It is an easy to achieve automatic control and intelligent control of the hydraulic components.
Study on Technological Parameters of Polishing Large Aspheric Elements
Authors: Chen Xian Hua , Zhong Bo , Yuan Zhi Gang
Published: December 2012

Large aspheric elements in giant laser facility are fabricated using computer controlled rapid polishing technology. The technological parameters are main influencing factors of efficiency. Base on Preston hypothesis, linear relationship of material removal with polishing pressure, polishing velocity and other conditions are established. According to the material removal function model of computer controlled rapid polishing, the removal function is simulated using MATLAB software. The influencing factors of volume removal efficiency are analyzed. In practice, the optimum polishing parameters are eccentricity 0.4, rotational velocity of principal axis 330 rpm, rotational velocity of polishing pad -600 rpm.
Design and NC Manufacturing of Plastic Injection Mold Based on UG Software
Authors: Li Shan , Xu Liang , Wang Yu Qi
Published: December 2012

On the platform of the UG Software’s CAD/MoldWizard/CAM components, the whole process of design and NC manufacturing of the plastic injection mold of a hair dryer’s shell was completed. The CAD/CAM process of the plastic injection mold was introduced by the practical application. The large advantage of the UG platform over the traditional method in the field of plastic injection molds’ design and manufacturing was reflected. The plastic injection molds’ design and manufacturing is a great challenge to the traditional design and manufacturing method, and the UG solutions can promote mold manufacturers’ ability of design and manufacturing remarkably.
The Control Software of Aspheric Optics in MRF
Authors: Yuan Zhi Gang , Zheng Nan , Chen Xian Hua , Hou Jing
Published: December 2012

Based on the mechanism of magnetorheological finishing(MRF), a material removal model was established. The dwell time function was solved by Jansson-Van Cittert algorithm to accomplish the kernel module design. Thus the control software of aspheric optics in MRF was designed. In order to verify accuracy of the processing control software, experiments were carried out on large aperture aspheric optics and the wavefront error of elements was achieved rapidly convergence. It is proved that the software could control the whole polishing process accurately.
Development of Simulation System for Absolute Photoelectric Encoder
Authors: Liu You Yu , Zhang Jun , Tian Xiao Qing
Published: December 2012

To change the current phenomenon of “Being an armchair strategist” of photoelectric encoder, a virtual absolute photoelectric encoder is developed using virtual reality techniques. The fundamental theory of absolute photoelectric encoder is expatiated, and then the development strategy is included. Some key technologies and their resolutions are presented in development, including the formation methods for static coded disc and dynamic coded disc. The simulation examples of binary code and gray code are showed subsequently. This paper provides a worthwhile and meaningful assistive tool for the development of absolute photoelectric encoder.
Design and Implement of Human-Computer Interaction Interface for Electronic Chart
Authors: Zhou Wei Dong , Liu Meng Meng
Published: December 2012

With the development of modern marine navigation technology, the importance of electronic chart is highlighted. As an agent and communicating window between people and electronic chart, the human-computer interaction interface is turning towards humanization and intelligence. In this paper, a compact, perspicuous and easily to be operated human-computer interaction interface is given based on the study and analysis about the design principles of human-computer interaction interface and international standards for electronic chart. And this interface is realized by using the VC++ technology.
Reliability Evaluation of Circular Tool Magazine and Automatic Tool Changer
Authors: Lu Xiao Hong , Han Peng Zhuo , Wu Wen Yi , Jie Wei
Published: December 2012

Tool magazine and automatic tool changer is important parts to fulfill the machining center tool reserve and automatic changing of the spindle tool. The reliability of them directly affects the performance of the host. But recently there are no researches on the reliability evaluation methods, so considering this situation, the reliability evaluation researches on CNC machine tools and their main parts at home and abroad are analyzed and concluded. Combining the collected failure data of the circular tool magazine and automatic tool changer, use MTBF (Mean Time between Failures), MTTR (Mean Time To Repair) and the inherent availability index to realize the reliability evaluation of the circular tool magazine and automatic tool changer. Thus put forward a method to study the reliability evaluation of circular tool magazine and automatic tool changer.
Tool Path Generation for Top Planar Surface of Ribs in Aircraft Structural Parts
Authors: Tang Yun Long , Zheng Guo Lei , Du Bao Rui , Chen Shu Lin
Published: December 2012

In order to solve the problem regarding the rapid NC machining programming for top planar surface of ribs in aircraft structural parts, an approach based on skeleton extraction technique is presented here to generate tool path for top planar surface. Firstly, the constrained Delaunay triangulation is built to split the rib top planar surface into several sub areas and approximate skeleton branch of each sub area is extracted. Then based on these skeleton branches and process scheme, the set of machining cells of the rib top planar surface is constructed. Secondly, the problem on determining the sequence of machining cells is resolved by optimizing the machining path. Finally, the sequence of machining cells can be converted into the machining cells chain from which tool path can be calculated by CAM systems. Based on the experimental results of the comparison between the generalized pocket method and our approach, our approach is found to be more efficient in generating tool path for top planar surface of ribs.
Effect of Slit Width on the Results of Small-Angle X-Ray Diffraction
Authors: Zhang Hua Yong , Liu Xiao Jian
Published: December 2012

X-ray diffraction analysis is a convenient and important route to investigate crystalline materials. With mesoporous materials, Al-SBA-15 as target, the effects of scatter slit, soller slit and receiving slit of Bruker D8 ADVANCE diffractometer on the small-angle diffraction pattern based on information, such as the background intensity, peak height, intensity and full width at half maximum, which provide the evidence for slits selection.
Application of Least-Squares Support Vector Regression with PSO for CPU Performance Forecasting
Authors: Lin Kuo Ping
Published: December 2012

The success of CPU performance prediction will make many benefits. This study adopts the least-squares support vector regression (LS-SVR) with particle swarm optimization (PSO) algorithm to improver accuracy of CPU performance prediction. LS-SVR with PSO, support vector regression (SVR) with PSO, general regression neural network (GRNN), radial basis neural network (RBNN), and linear regression are employed for CPU performance prediction. Empirical results indicate that the LS-SVR (Linear kernel) with PSO has better performance in terms of forecasting accuracy than the other methods. Therefore, the LS-SVR (Linear kernel) with PSO model can efficiently provide credible CPU performance estimated value.
Approach of Combination of Weighted Evidence Based on Evidential Closeness Degree and its Application
Authors: Zhao Zhuan Zhe , Jia Min Ping , He Kang , Zhou Hao , Ding Yu Jie
Published: December 2012

Since the information fusion based on Dempster-Shafer(D-S) evidence theory involves counter-intuitive behaviors when evidences highly conflict, a new approach of combination of weighted based on evidence closeness degree is proposed and applied in fault diagnosis．Firstly, the calculation method of evidence distance and evidential closeness degree as well as its revision are given according to the relevance and importance of various evidence sources; Then the closeness degree is normalized in order to obtain the weights of evidence sources. And the information fusion is realized with the base of weighted evidence theory. Finally, the approach is applied to fault diagnosis model of multi-evidences (multi-symptom domains or multi-sensors) in this paper. In the experiments, the proposed approach is compared with the existing combination rules and the results show that the reliability and accuracy of fault diagnosis are significantly improved and its uncertainty is decreased remarkably. The fusion problem given above is also solved effectively.
Kinetic Study of Intermetallic Formation on Die Material in Aluminum Molten Alloy Containing Various Additional Elements
Authors: Kim Bong Hwan
Published: December 2012

The formation behavior of intermetallic layers on die material immersed in aluminum molten metal was investigated by using dipping test facility. And the metallurgical parameters affecting on the kinetics of intermetallic formation were discussed as functions of additional elements such as Fe, Mn and Cr in order to propose a practical guideline for control of molten metal in manufacturing processes. It was found that the intermetallic layers consist of α-AlFeSi, β-AlFeSi and θ-AlFe. The kinetic of intermetallic formation was highly dependent on not only the gradient of iron content through the interface between die material and molten alloy but also the relative formation temperature of primary intermetallic phase.
Synthesis of Silicon Nanowire Arrays by Metal-Assisted Chemical Etching in Aqueous NH4HF2 Solution
Authors: Naama S. , Hadjersi T. , Nezzal G. , Guerbous L.
Published: December 2012

One-step metal-assisted electroless chemical etching of p-type silicon substrate in NH4HF2/AgNO3 solution was investigated. The effect of different etching parameters including etching time, temperature, AgNO3 concentration and NH4HF2 concentration were investigated. The etched layers formed were investigated by scanning electron microscopy (SEM) and Photoluminescence. It was found that the etched layer was formed by well-aligned silicon nanowires. It is noted that their density and length strongly depend on etching parameters. Room temperature photoluminescence (PL) from etched layer was observed. It was observed that PL peak intensity increases significantly with AgNO3 concentration.
Age Hardening Behavior of Carbon Nanotube Reinforced Aluminum Nanocomposites
Authors: Saheb Nouari , Khalil Abdullah , Hakeem Abbas Saeed , Laoui Tahar , Al-Aqeeli N. , Al-Qutub A.M.
Published: December 2012

In the present work, age hardening behavior of CNT reinforced Al6061 and Al2124 nanocomposites, prepared by ball milling and spark plasma sintering, was investigated. The effect of CNT content, annealing time and temperature on the age hardening behavior of the nanocomposites was evaluated and compared to the monolithic alloys prepared and age hardened under the same conditions. It was found that CNTs have a negative influence on the age hardening of the alloys. The alloys displayed standard age hardening behavior i.e. a sharp increase in hardness during initial aging followed by a steady decrease in hardness. Whereas the nanocomposites did not only display initial softening during aging but also showed reduced age hardening efficiency. The hardening efficiency was found to decrease with increasing CNT content. The complicated behavior of nanocomposites was explained in terms of dislocation recovery, large thermal mismatch between matrix and CNTs and bulk microstructure of the composites.
Effect of Temperature and Carbon Contents on the Synthesis of β-SiC Powder
Authors: Won J.Y. , Kim Soo Ryong , Lee Y.J. , Ko Tae Gyung , Kim Y. , Kwon Woo Teck
Published: December 2012

Uniform nanosized β-SiC powders have been prepared in a flow reactor by thermal pyrolysis using organometallic precursors with different C/Si mole ratios such as methyltrichlorosilane and triphenylsilane. The temperature was varied from 1200°C to 1400°C. In order to examine the pyrolysis residue after the reaction, the sample was collected and analyzed with XRD, Raman and TEM. The X-ray diffraction result of the pyrolysis residue shows that the diffraction peaks around 35°, 60°, and 73° correspond to the beta SiC phase. All the diffraction peaks were quite broad, which indicated that the SiC powder was in the early stage of crystallization at this heat treatment temperature.
Preparation of Hydrophobic Silica Aerogels from Industrial Microsilica and its Oil Adsorption Properties
Authors: Shi Fei , Liu Jing Xiao , Dong Xiao Li , Zhang Zhi Wei , Du Peng Cheng , Wang Xiao Jie , Zhang Xin Xin
Published: December 2012

Hydrophobic silica aerogels were prepared from industrial microsilica via ambient pressure drying. The process consists of two stages, synthesis of sodium silicate solution from microsilica by hydrothermal reaction with sodium hydroxide, and preparation of silica aqueous gel and porous silica aerogels from the obtained sodium silicate solution. The mixed solution of hexane/ethanol/trimethylchlorosilane was used to modify the sol-gel derived silica aqueous gel so as to obtain porous structure by ambient pressure drying. The microstructure, pore properties of the silica aerogels were analyzed by FTIR and N2 adsorption-desorption methods, and the oil adsorption of the synthesized silica aerogels was investigated. The results indicate that the obtained silica aerogels are light-weight and hydrophobic porous materials, with the specific surface area of 767~828 m2•g-1, porosity of 91.5~95.1% and the average pore diameter of 5.22~8.02 nm. The synthesized silica aerogels have good oil adsorption capacity and the highest saturated oil adsorption rate can achieve 1105%.
Synthesis and Characterization of Mesoporous Carbon Functionalized with Carboxylate Groups for a Promising Adsorbent
Authors: Chi Yue , Li Yan Juan , Li Xiao Tian
Published: December 2012

Mesoporous carbon material CMK-3 was successfully prepared by using mesoporous silica material SBA-15 as hard template and sucrose as carbon source through a nanocasting method. In order to improve the hydrophilic properties of the carbon materials, a large amount of carboxylic functional groups have been introduced upon the surface of carbon materials by oxidative treatment. Transmission electron microscopy (TEM) exhibit highly ordered mesostructure with 2-D hexagonal symmetry of our sample. An absorption assigned to the -COOH groups is clearly visible in Infrared spectra, suggesting the presence of carboxylic functional groups. Rhodamine B (Rh B) was selected as a model for determining the adsorption activity of the obtained material. This material exhibited a high adsorption capacity, and an extremely rapid adsorption rate.
Surface Integrity and Anti-Fatigue Mechanism of 30CrMnSiNi2A Steel with Shot Peening Treatment
Authors: Li Zhan Ming , Zhu You Li , Du Xiao Kun , Liu Kai Liang
Published: December 2012

In this study, 30CrMnSiNi2A steel specimens were treated by shot peening technique. In order to evaluate the effects of shot peening process on the surface characteristics, the surface topography and roughness of the treated and untreated specimens were observed and analyzed using scanning electronic microscope (SEM) and surface profile tester. Surface microstructure and residual stress were observed and analyzed using transmission electron microscope (TEM) and X-ray stress apparatus respectively. Results show that the surface roughness of milling specimens could be reduced from Ra 4.45 μm to 2.39 μm using shot peening process. Severe plastic deformation and grain refinement were also induced by the process, and the average grain size of nano-structured regime was about 46 nm. Moreover, a 300 μm compressive residual stress layer with the -766.5 MPa compressive residual stresses was induced. At the same time, the anti-fatigue mechanism of shot peening was discussed.
The Preparation of Ceria-Based Solid Electrolyte and the Influence of Manganese Oxide on the Performance of the Electrolyte
Authors: Zhang Zhi Juan
Published: December 2012

Ceria-based solid electrolyte was prepared by low-temperature combustion method, and the synthesis technology was discussed. It can be found that the advantages of choosing citric acid as reducing agent were higher yield and easier reaction control. The crystalline growth of samples was tended to complete when the pre-sintering temperature was 700°C. There was not stratification phenomenon when the forming pressure was 400 MPa. Nano-scale powders were obtained by this way, which caused decreasing of sintering temperature. The effects of Ce0.8Gd0.2O2-δ (CGO) doped manganese oxide as sintering additive on density and conductivity were studied. The relative density of CGO doped 2.0 mol% MnO1.333 (2Mn-CGO) increased within a certain temperature range because of the occurrence of viscous flow sintering. The conductivity measured at 700 °Cof 2Mn-CGO sintered at 1100 °C was 4.52×10-2 S/cm, which is higher than that of CGO.
Modes Excitation in Five-Mode Photonic Crystal Waveguides of Triangular Lattice
Authors: Shi Xiao Yan , Yang Wu , Yang Hua , Wang Xiu Ze
Published: December 2012

We study modes excitation with input field of different positions in five-mode photonic crystal waveguides of triangular lattice. The five-mode photonic crystal waveguides is formed by removing five rows rods in 2D photonic crystals of a triangular lattice of dielectric rods in air. The 0th mode, the 1st mode and the 2nd modes are selectively excited. The input field with different positions can excite different modes due to the field intensity distribution of modes. When the input field locates at the position of the zero field intensity of the waveguide mode, the mode can not be excited. The superposition of different modes can leads to different field intensity distribution. The finite-difference time-domain method is used to obtain the excited field distributions.
Laser Cladding Fe-Al Intermetallics Coatings on ZL114A Aluminum Alloy
Authors: Ye Hong , Peng Shi Xin , Yan Zhong Lin , Zhang Xiao Bin
Published: December 2012

The mixed powders of 70%Fe and 30%Al were precoated, and Fe-Al intermetallics coatings were produced on an aluminum ZL114A alloy by means of laser cladding. The microstructure and hardness of the coatings are analyzed by using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and microhardness testing machines. The results show that a fine surface quality can be obtained under a suitable process parameter of laser. The laser cladding layers are mainly consisted of phases of FeAl3, Fe3Al, FeAl with lump-like, granular, equiaxial and needle-like. The highest microhardness of the cladding layer achieved HV614 and raised 5~6 times in comparison to substrate.
Luminescent Properties of Eu3+-Doped BaGd2ZnO5 Phosphors for White LED
Authors: Noh Hyeon Mi , Yang Hyun Kyoung , Moon Byung Kee , Choi Byung Chun , Jeong Jung Hyun , Jang Ki Wan , Lee Ho Sueb , Yi Soung Soo
Published: December 2012

BaGd2ZnO5:Eu3+ phosphors were synthesized at sintering temperatures of 800, 900, 1000, 1100 and 1200 °C by high-energy ball milling method. The crystallinity, surface morphology and photoluminescence properties of phosphors were investigated by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and luminescence spectrophotometry, respectively. The XRD results indicate that the crystallinity of the powder was improved and the powder shows a orthorhombic structure as the sintering temperature increased. The emission spectra of BaGd2ZnO5phosphors excited at 280 nm exhibit a series of shaped peaks assigned to the5D0→7FJ(J=0, 1, 2, 3) transitions, and luminescence intensity was increased with increasing sintering temperature. The FE-SEM images indicate that the size and shape of particles are regular.
Characteristics of New Absorbent System of Heteropoly Compound Solution for H2S Removal
Authors: Wang Jing , Wang Rui
Published: December 2012

A new liquid redox method for low sulfur containing gas treatment, with H2S concentration less than 1000mg/m3, was developed employing the heteropoly compounds of molybdenum and phosphorus by the present authors. The desulfurization characteristics of the absorbent system of vanadium substituted heteropoly acid, viz. H4PVMo11O40, were investigated by dynamic outlet-gas H2S concentration detection method. Like the aqueous solution of the parent compound, namely H3PMo12O40 or its sodium salt, H4PVMo11O40 solution can also be used as efficient absorbent for H2S removal. The absorbent system of H4PVMo11O40 solution was found to have fairly good absorption-regeneration performance, with a H2S removal rate of up to 100% in the presence of CuS as additive, hence it is promising in pollution control and resource reclamation.
High Pressure Effect on Reaction Synthesis of Ti2SC Powder
Authors: Zhu Wen Bin , Mei Bing Chu , Tu Yong Wei , Song Jing Hong
Published: December 2012

Ti2SC has been synthesized using Ti/TiS2/2TiC as initial materials. Combining X-ray diffaraction analysis with thermodynamic calculations, a reaction path is proposed for the intermediate phase TiS and Ti2SC formation. TiS was more possible to be obtained from TiS2 and Ti rather than the decomposition of TiS2. TiC was the main impurity phase in Ti2SC and was difficult to eliminate. The high pressure technology using can help improve the purity of the sample. Scanning electron microscopy (SEM) shows the typically layer structure of the material. Thermogravimetry (TG) and differential scanning calorimetry (DSC) are also to be used to investigate the reaction mechanism，indicating that it would be useful for the formation of more purity sample by adjusting the content of TiS2.
Measuring Electrical Conductivity of Al-Sc Alloy by Application of Continuously Varying Cell Constant Technique
Authors: Guo Rui , Zhang Bing , Zhang Wen Xi
Published: December 2012

The electrical conductivity of the molten salts of Na3AlF6-LiF-Sc2O3 system with different compositions was measured at different temperatures by the continuously varying cell constant technique. The main influence factors on electrical conductivity were analyzed. Experiment results showed that the technique of the electrical conductivity measurement is accurate and reliable and the result’s relative error is just 0.67% in comparison with those in relevant literature. With temperature rising, electrolyte conductivity increases at a rate of about 0.03S/cm for 1°C. And we also found that the conductivity increases slightly with the addition of lithium fluoride and adding scandium oxide makes the conductivity decrease slightly and more addition doesn’t cause significant effect. It was proved that the technique can measure accurately the electrical conductivity of aluminium electrolyte and other high-temperature molten salts.
Transfer Behavior of Clove Oil/β-Cyclodextrin Inclusion Complex in Antibacterial Film Based on PVA
Authors: Jiang Ping , Hao Xi Hai , Sun Miao
Published: December 2012

The antifungal PVA film was fabricated by addition of the clove oil/β-cyclodextrin (β-CD) inclusion complex into PVA. The migration of clove oil in different food simulation solution (A: 10% ethanol water. B: 50% ethanol water. C: 60% glycerin-water mixture. D: n-hexane) were evaluated by using solution food simulation and then treated with linear regression analysis. The diffusion coefficient was cultivated out by Matlab software. The migration of clove oil which was embedded by β-CD in PVA film was influenced by the quality of food simulation solution to a great degree and the relation among the migration rate was A>B>D>C. The film structure was loosed and the migration gallery was increased by adding clove oil/β-cyclodextrin inclusion complex. The migration amount in simulations was positively correlated with time and diffusion coefficient.This kind antibacterial film can be used in low water activity food system and kept long-term antibacterial action.
Polishing of CVD Diamond Wafers and Films
Authors: Feng Hai Bo , Chen Yi Qing , Zhang Liang Chi
Published: December 2012

This paper investigates the applicability of the dynamic friction polishing (DFP) technique to process the chemical vapour deposition (CVD) diamond surfaces. Two types of CVD diamond specimens were studied. A stepwise polishing process was introduced to minimise the cracking in CVD thin films. The investigation focused on the polished surface quality in relation to the polishing conditions and material remove rates. It was found that by selecting proper polishing parameters, surfaces of quality finish with a roughness of less than 70 nm Ra could be obtained in 15 minutes when the specimens were CVD diamond wafers with an initial roughness of 17 μm. The polishing time could be reduced to only 2.5 minutes in the case of diamond thin film specimens of initial roughness of 1.6 μm.
Effect of Growth Temperature on the Morphology of ZnO Films Grown in Aqueous Solutions
Authors: Wu Qiu Fang , Wang Si Si , Yao Feng Lan , Zhang Chun Mei , Li Mi Dan
Published: December 2012

The well-aligned nanoflower and nanorod films were synthesized using zinc acetate- sodium hydroxide aqueous solutions at different growth temperature. These microstructures were characterized with field emission scanning electron microscopy and the X-ray diffraction. The predominant c-axis growth of hexagonal lattice was observed in the ZnO films, and the growth temperature was found to play an important role in controlling the morphology of ZnO films. Mechanism of formation of varying morphologies was discussed.
Influence of Silicon Texturization on the Photovoltaic Properties of CuPc/n-Si Hybrid Solar Cells
Authors: Liu Zhi Feng , Liu Yi Ting
Published: December 2012

Hybrid solar cell based on copper-phthalocyanine (CuPc) and textured Si has been fabricated. Influence of silicon texturization on the photovoltaic properties of CuPc/n-Si hybrid solar cell was studied by current-voltage characteristic curves in the dark and under illumination conditions. As a result, it is found that textured Si can improve significantly the performance of hybrid solar cell. It exhibits a three times increase in the short-circuit current density with respect to that of the standard hybrid solar cell, and the short-circuit current density reaches up to 5.4 mA/cm2. In addition, the open-voltage and fill factor are almost constant. The solar-energy conversion efficiency is increased by about three times by the textured Si and achieved about 0.8% under “one Sun” illumination. Furthermore, the possible reasons for this result have been discussed.