bluuebunny/crossref_metadata_2025 huggingface dataset:
Comment on Lee J-s et al.'s Identity-Based Designated Verifer Proxy Signature Scheme and its Improvement
Authors: Liao Da Jian , Tang Yuan Sheng
Published: November 2010

In a designated verifier proxy signature scheme, one can delegate his or her signing capability to another user in such a way that the latter can sign messages on behalf of the former, but the validity of the resulting signatures can only be verified by the designated verifier. Recently, Lee J-s et al. proposed a new ID-Based designated verifier proxy signature scheme. They didn't analysis the security of their scheme. We found out that anyone can generate a valid signature on any message m and mw he choose. To overcome this flaw in Lee J-s et al.'s scheme, we formalized the notion of designated verifier proxy signature scheme, provide a new ID-Based designated verifier proxy signature scheme. We also analyzed the proposed scheme.
Robust Motion Objects Detection in Moving Camera Scenes
Authors: Zhong Yang Jun , Zhang Shui Ping
Published: November 2010

This paper presents an efficient method for motion objects detection in dynamic background.Three main aspects compose the proposed method.Firstly,abundant SIFT matching pairs were obtained from two successive frames.Secondly, a robust global motion estimation method based on SIFT matching pairs was presented.Finally, the moving objects could be detected after we compensate the global motion.Evaluations based on extensive experiments have shown that the proposed method can achieve the motion detection in dynamic backgrounds.
Numerical Simulation of Air-Deck Slotted Charge Blasting
Authors: Yang Guo Liang , Yang Ren Shu , Huo Chuan , Che Y.L.
Published: November 2010

Air-deck ratio plays a decisive role in blasting engineering. Researchers have conducted extensive work to study the optimal air-deck ratio. But consensus has not been achieved. Especially slotted charge blasting, the study on it just starts. For its complicated physical process in blasting, it is difficult to perform theoretical analysis to obtain the law between blasting result and air-deck ratio. The numerical simulation method is adopted to study the effect of different air-deck ratio on stress distribution at first. And then laboratory tests are carried out to validate the simulation results. The conclusion may be drawn that good directional fracture could be obtained with air-deck ratio 33.3% ~ 50%. The achievement could provide reference for blasting engineering.
Creep Behaviors of 3D C/SiC in High Speed Combustion Gas at 1300°C
Authors: Luan Xin Gang , Cheng Lai Fei
Published: November 2010

To understand the creep damage mechanism of a standard 3D Carbon fiber reinforced silicon carbide composite (C/SiC) in high temperature combustion gas at 1300 °C, the creep tests were carried out in a combustion wind tunnel and the mechanisms were investigated by the extension of specimens and the microstructure of fracture section. It was found that the external tensile load was bore by the carbon fibers in the active region during the stressed oxidation process. The oxidation mechanisms of the active region were determined by a normalized threshold stress. Below the normalized threshold stress, the oxidation was controlled by internal diffusion of oxidizing gases through microcracks in SiC matrix. Above the normalized threshold stress, the oxidation was controlled by the reaction of carbon fiber with oxygen and water vapor.
The Design and Implementation of Baiyangdian Tourism Business System Based on Web Service
Authors: Xu Huan Xin , Lai Ji Min
Published: November 2010

If the tourism e-business system has the characteristics of platform independence, scalability and portability, it will be useful for improving the level of service and management of the tourism, and further quicken the step of tourism industry. Web Service provides a kind of new distributed computing technology; it can embody business application services by standard XML protocol and information format on Internet or Intranet. According to the demands of a typical tourism business platform, this paper designed a loosely coupling and easily scalable system scheme, what’s more, carried it out in the final. All attained the expect goal.
Relations of A*H and AH
Authors: Yan Yan , Mi Cui Lan , Wang Xin Chun
Published: November 2010

In this paper, we study the concept of the right twisted smash product algebra A*H over weak Hopf algebra. Let H be a weak Hopf algebra and A an H-module algebra, using the properties of the trace function we describe the finiteness conditions for H-module algebras.
Study on High-Rise Building Transfer Floor
Authors: Wang Bin , Yang Hui Qin , Zhang Wen Xin
Published: November 2010

The beam shape of concrete transfer floor is completely studied. Firstly, for the system of moulding board and support frame in construction the side pressure and screws are analyzed. The material and structure form of support frame are discussed. The design of support frame uses the method of limited state, and also it analyses the integer stability, part stability, and single stability, and then proposes the load analysis of multi level support frame. To the high-rise building's support frame, the dissertation proposes the approximate calculation based on half-rigidity steel frame. Finally, the dissertation takes ** square for example with the analysis of the support frame of transfer floor and temperature cracks' control. Especially the use of calculation software gets a good effect for the research on the support system of transfer floor. High-rise building transfer floor is the important part of building construction, also is the most difficult part in building construction. The construction technique references intersection application of dynamics, materials, construction design & management etc. subject, it is a complex system project [1]. The key factor is lied support system of transfer floor construction, pouring plan of concrete, maintain concrete at later stage, temperature control technique of concrete [2,3] in high-rise building transfer layers construction. However each area is the new project which transfer floor construction face, in order to keep successful & efficiency to complete the high-rise building transfer layer construction, this requests construction should according to the reality situations, can convenient apply some directly theory system to use, & combine with similar projection experiences, then solve the above problems in quick, efficiency. Under the development trend of high-rise building becoming more and more, how to satisfy the needs of engineering construction, conclude a suite easy, accurate and efficiency technique theory system of high-rise building transfer layer construction, it becomes the reality project in construction technique which need to be solved. From the practice experiences of passed projects, the quality of transfer floor construction references all the project quality directly, and occupies obvious building cost. It is the importance of design consideration plans for whole construction to technique designs carefully, accurate, economy, and the strict control of construction group, and should consider the risk in construction process. So it is necessary to the project study of high-rise building transfer layer construction technique.
Simulation Study on Laser Welding of High Strength Steel to Vehicle
Authors: Wu Qiang , Tang Yong , Yang Yong Qiang , Li Yu Zhong
Published: November 2010

Based on quasi-stable state heat-transfer control mode, finite difference equation of thermal conductivity in laser welding is deduced. Physical parameter (specific heat) substitutes for phase-changing latent heat, then critical temperature of thermal conductivity welding is determined, so finite difference equation can be solved by MATLAB software. Temperature field distribution is simulated to weldment.Influence of technological parameters such as laser power and welding speed on temperature field are investigated systematically by numerical simulation, these can establish theoretical basis for optimization of technological parameters in laser welding.
Motion Control and Design for Experimental Feeding Device
Authors: Zhang Xiao Gui , Gao Bo
Published: November 2010

In order to study the performance of speed feeding, an experimental feeding device was designed. The main design considerations are: Easy to adjust parameters, separate movement control of each device structure, and distribution control for the suction and blowing in the feeding device. The control system is developed on windows PC system. KPCI-884 motion control card is adopted as the I/O interface for the motion control, feeding movement is driven by servo motors, a high-speed solenoid valve is used for gas distribution and system UI is developed in VC++ language. A test run indicates that the system is in good operational condition. In the research, the synchronous control of multiple servo motors in a open-loop state is achieved as well as the detection and control of peripheral signals.
The Study of Problems and Countermeasures of Current Basic Computer Education in College
Authors: Wu Peng
Published: November 2010

With the rapid development of information technology, many changes and problems have taken place to the basic computer education. A systematic investigation of related issues and a study of countermeasures to solve the corresponding problems according to the author’s own practice and experience in educational reform will be presented in the paper
Influence of Silane Coupling Agent on Interfacial Strength of SMA Composite
Authors: Wang Yu Long , Wang Zhen Qing , Zhou Li Min , Huang Hai Tao
Published: November 2010

Shape memory alloy (SMA) can be embedded into a host material to achieve shape control, damage repair and self-adaption. It is well recognized that the applications of SMA composites are highly dependent on the integrity of SMA fiber-matrix interface. However, the interfacial debonding often occurs due to the weak bonding of interface between the SMA wire and its surrounding matrix. Therefore, it is necessary to improve interfacial strength of SMA composites. In present paper, the epoxy resin is functionalized by mixing different amount of silane coupling agent to improve the interfacial adhesion of SMA fiber reinforced epoxy matrix composite. The single fiber pull-out test is carried out to evaluate the interfacial strength and the test results indicate that the interfacial strength of SMA composite is improved significantly as compared to the results from unfunctionalized samples.
Wind-Induced Response Analysis of Guyed Mast Earplate Considering Welding Residual Stresses
Authors: Wang Wen Li , Qu Wei Lian , He Jie
Published: November 2010

This paper proposes a new method to calculate the wind-induced dynamic stress response of guyed mast earplate node, which considering the welding residual stresses in earplate weld joint. Firstly, a numerical simulation of weld residual stress of key nodes based on finite element method is presented. Then, taking the welding residual stresses as initial stress, the dynamic stress analysis of the guyed mast earplate’s weld was completed. The results show that in the dual role of the welding residual stress and the wind load, the von Mises equivalent stress of some hot spots in welds have exceeded the material yield stress of steel.
A Personalized Recommender Systems Framework Based on Ontology and Bayesian Network in E-Commerce
Authors: Long Fei , Zhang Yu Feng , Hu Feng
Published: November 2010

Personalized recommendation methods are mainly classified into content-based recommendation approach and collaborative filtering recommendation approach. However, Both recommendation approaches have their own drawbacks such as sparsity, cold-start and scalability. To overcome the drawbacks, In this paper, we propose a framework for recommender systems that join use of Ontology and Bayesian Network. On the one hand, Ontology help formally defining the semantics of variables included in the Bayesian network, thus allowing logical reasoning on them. On the other hand, Bayesian network allow reasoning under uncertainty, that is not possible only with the use of ontology. In the recommendation, products not yet purchased or rarely purchased can still be recommended to customers with accuracy.
Robust Adaptive Inverse Optimal Tracking for Strict-Feedback Stochastic Nonlinear System
Authors: Wang Lu
Published: November 2010

For a class of strict-feedback nonlinear systems with unknown constant parameters, uncertainty in the input gains and standard Wiener-noise, combining the system function with the known reference signal, the error system is obtained. The adaptive inverse optimal controller and adaptive laws of parameters are designed using Backstepping algorithm, thus the robust adaptive inverse optimal tracking problem of original system is solved．
The Development of Short Stress Path Experimental Asymmetric Multifunctional Rolling Mill
Authors: Chen Ze Jun , Huang Guang Jie , Min Jian Jun , Qian Boa Hua
Published: November 2010

This paper describes the development and design of a novel short stress path rolling mill which is used for teaching and research. The rolling mill can implement the asymmetric rolling by the way of the adjustment of upper roll speed, and also working as conventional rolling when the roll speeds of two rolls are equal. The rolling mill can produce not only the plate and sheet, but also profiles by the roll of different grooves. The rolling mill is appropriate for the rolling of the steels and nonferrous metals. In this paper, the design ideas and main parameters of principal components are presented with respect to the new rolling mill. It can provide references for the design and manufacture of rolling mill of similar functions and structures.
Influence of Roll Profile Configuration on High-Strength Strip Flatness Control Performance in Tandem Cold Rolling
Authors: Wen Jie , Zhang Qing Dong , Zhang Xiao Feng , Ye Xue Wei
Published: November 2010

According to the characteristic of high-strength strip, the roll profile configuration and change of CVC tandem cold mill are analyzed. Through the establishment of FEM model, the influences of three representative forms of roll profile configuration on high-strength strip flatness control in CVC cold rolling mill are compared, which are conventional back-up roll / CVC intermediate roll, back-up roll with CVC compensation / CVC intermediate roll, VCL+ back-up roll / HVC intermediate roll. Compared with the other two roll profile configuration, the configuration of VCL+ back-up roll / HVC intermediate roll increases 26.74% in crown adjustment domain of roll gap and 22.09% in lateral stiffness of roll gap, decreases 27.43% in contact pressure peak values between rolls. The new roll profile configuration has obtained industrial applications. Production data indicate that the control accuracy of high-strength strip is improved, also the wear of back-up roll. Significant application results have been achieved.
Mechanism of Cross Bow in Single-Roll Transmission Temper Mill
Authors: Dai Jie Tao , Zhang Qing Dong
Published: November 2010

In a 1220mm temper mill, the cross bow was serious, which seriously affected the unit’s output and efficiency. In order to solve this problem, the mechanism of cross bow is studied in rolling of single-roll transmission temper mill. First, established the FEM of the single-roll drive temper mill rolling, analyzed the distribution factors of vertical extension in thickness. Second, used the method of symplectic elasticity to establish the analytical calculation model to study the relationship between the cross bow with the uneven vertical extension, explained the mechanism of cross bow. Then, used ANSYS to establish finite element model which further analyzed the cross bow under different distribution of extension in width direction. On the basis of analyzed the mechanism, proposed measures to reduce the value of cross bow. These measures have been applied in production; the effect of application was obvious.
Research on the Tendency of Inner Crack during 3-Roll Skew Rolling Process of Round Billets
Authors: Li Sheng Zhi , Meng Wen Hua , Hu Lan Wei , Ding Bo
Published: November 2010

Concerning the 3-roll skew rolling process of round billets, a 3-D thermo-mechanical coupled simulation is performed with the aid of commercial FE code MSC.SuperForm. The influence of the feed angle and inlet cone angle of the roll on the strain and damage filed are investigated. It is found that the distribution pattern of the equivalent plastic strain in the longitudinal section of the billet presents U-shape, and that the feed angle and inlet cone angle of the roll make difference in the gradient of deformation intensity in radial direction of round billet. The ring-shaped distribution of the damage field in transverse cross section of the billet indicates a high tendency for the ring-shaped inner crack to occur, instead of the center crack appearing in 2-roll skew rolling of round billet. The results show that the critical parameters to control the ring-shaped crack during the 3-roll skew rolling process are the feed angle and inlet surface cone angle of the roll. It should be avoided to use too large feed angles so as to reduce the tendency of annular inner crack in the actual rolling of high-alloy steels with poor hot workability.
Study of Si/Al Ratio and Modification of Silicon Morphology in ZA27 Alloys
Authors: Luo Xiao Ping , Xia Lan Ting , Zhang Ming Gang
Published: November 2010

Changes in the primary Si phase in Al-Si alloys were analyzed and compared to the Si phase in ZA27 alloys with the same Si/Al ratio. The Si phase in the Al-Si alloys was modified and applied to ZA27 alloys to refine the Si phase of the microstructure. The results showed that the change in the ZA27 alloys was the same as that in the Al-Si alloys while good modification effects were obtained with a 1.5% Cu-P inter-alloy using two different processes.
Parameter Estimation for Small Sample Censored Data Based on SVM
Authors: Fan Ying , Wang Shun Kun , Zhou Feng , Tian Zhi Cheng , Ding Guang Shuai
Published: November 2010

It is difficult to identify distribution types and to estimate parameters of the distribution for small sample censored data when you deal with mechanical equipment reliability analysis. Here, an intelligent distribution identification model was established based on statistical learning theory and the algorithm of multi-element classifier of Support Vector Machine (SVM), and also applied to parameter estimation of small sample censored data, in order to improve the precision of traditional method. Firstly, the algorithm of training based on SVM and the RBF kernel function was selected; secondly, the parameters of the distributions characteristics were drawn; on the basis of these conditions, the distributions identification model and the parameter estimation model were finally constructed. And the model was verified with Monte Carlo simulation method. The results indicate that the new algorithm has more preferable performance in distribution type identification and parameter estimation than the traditional methods.
Microstructure Formation and Mechanical Properties in AZ31 Alloy Processed by Continuous Rheo-Extrusion
Authors: Guan Ren Guo , Zhao Zhan Yong , Cao Fu Rong , Sun Xiao Ping , Zhang Qi Sheng
Published: November 2010

Based on continuous casting and extrusion (CAXTEX) process, a semisolid metal forming process, continuous rheo-extrusion of magnesium alloy, was proposed. Effect of casting temperature on semisolid region distribution, microstructure formation and stability of forming process, as well as microstructure and mechanical properties of the AZ31 alloy fabricated by the process were investigated. Microstructure evolution from dendrite to rosette or spherical grains was observed with the application of large shearing force provided by the roll. The results indicate that semisolid region in the roll-shoe gap moves downward gradually with the increase of casting temperature, and proper casting temperature range of 730~750°C is suggested. Under the suggested casting temperature, 10×15mm sectional bar of AZ31 alloy with smooth surface and homogeneous striped microstructure has been obtained. As the product was aged for 14h at 180°C after 16h solution at 415°C, the ultimate tensile strength and elongation could reach 305MPa and 11.5%, respectively.
Research on the Impact Pressure of the Hydraulic Rolling-Cut Shear
Authors: Wang Jing , Han He Yong , Huang Qing Xue , Wang Jun
Published: November 2010

The reasons for impact pressure are obtained by the research the hydraulic system of Hydraulic Rolling-Cut Shear. The impact pressure of hydraulic system is divided into direct impact and indirect impact. Based on analyzing the actual situation the measures should be taken to reduce the impact pressure when design hydraulic system. The suitable length of pipeline can improve the performance of the hydraulic system because the length is important for the impact pressure. The accumulator can absorb impact pressure and improve the work situation of servo valve. Therefore, the suitable accumulators should be set in the hydraulic system. The study provides theory basis for the pipe design of large hydraulic servo system.
The Theory Analysis of the Blade Gap’s Adjusting for Rolling Shear
Authors: Fan Fei , Li Yu Gui , Gui Hai Lian , Yang Fu Liang
Published: November 2010

The horizontal blade gap is a key problem in rolling shear. The mathematical model is established in this paper. This model is optimized based on traditional model. The optimized formula of blade clearance is obtained and the stress is analyzed in cutting process. It is benefit for improving shear quality.
Development of Automatic Control System for a Rolling Shear Line
Authors: Sun Qian Lai , Sun Zhi Yi , Yan Xue Wen , Li Hong
Published: November 2010

An automatic control system is developed for a rolling shear line in this paper in order to overcome the weakness of the traditional control system. All of motion mechanisms are driven by alternating current motors. The S7-300 PLC is selected as the control unit. And the PROFIBUS-DP field bus is employed to structure a distributed control system. Automatic cutting to length is realized. The rolling shear line has some merits such as high efficiency and precision, low cost and energy consummation ensured by the control system. The control system is reliable and flexible.
The Correlation of Assessment Parameters on Geometrical Features of SurfaceTexture
Authors: Yang Yu Fen , Han Zhen Nan , Li Jin Bao
Published: November 2010

The method quantitatively analyzing the correlation of assessment parameters on geometrical features of the surface texture with the approach degree theory of fuzzy mathematics is put forward, and the issue that the information provided by assessment parameters on indicating microscopic geometrical features of the surface texture is only analyzed qualitatively not quantitatively is solved accordingly. The experimental results clarify the correlation and the operational performance of the various assessment parameters; what’s more, it provides the reliable theoretical basis for the reasonable choice of the assessment parameters on microscopic geometrical features of the surface texture.
Research on Computer Simulation System for Special Straightening and Shearing of Wire
Authors: Sun Bin Yu , Du Xiao Zhong , Yang Xiao Rong
Published: November 2010

It is necessarily to study a new wire of economic section for market of building materials and development of social progress. Based on hardware to requirement of software, this paper exploits a computer simulation system for special straightening and shearing of wire, it face to the engineering directly. The software adopts the structure systems, which includes structure type, modularity, and expert system ability. The algorithm of the system is reliable. Its function is complete. Interface is friendly. It can be widely used in practical engineering.
Description and Control of Tin Plate Surface Visual Quality
Authors: Wang Bo , Zhang Qing Dong , Yu Meng , Zhang Xiao Feng , Ni Guo Hua
Published: November 2010

This article suggests that divide the strip surface quality into the damage class, the adhesion class as well as the surface vision class. In order to improve the surface vision quality of the tin plate, the chromaticity of gloss and lightness are used to measure the tin plate surface vision quality. Predictive models of gloss and lightness are established to determine the influencing factors by stepwise regression in the article. The research indicats: the gloss and lightness of tin plate are closely related with tin coating weight and the roughness of tin mill black plate, including profile arithmetic average error and superficial peak density. By enhancing the roughness control accuracy of tin mill black plate, the surface visual quality of tin plate has been greatly improved and the chromatic aberration after printing is solved.
Design and Analysis of Structure and Test System for Bearing-Rotor Test-Bed
Authors: Pang Xin Yu , Yang Zhao Jian , Liang Qun Long
Published: November 2010

In view of the structure and the installation process of a bearing-rotor test-bed, a complete test system was built for test bed. Some installation problems were reflected through signals detected by the sensor. At the same time, the test-bed has been adjusted targettly. These laid a good foundation for fault simulation and the next fault diagnosis work.
Intelligent Design of the Hydraulic Manifold Blocks Based on Rule-Based Reasoning
Authors: Du Shi Wen , Li Yong Tang , Song Jian Jun
Published: November 2010

Design of hydraulic manifold blocks is a kind of complex solid special layout problem. Due to the complexity of the manifold blocks layout, intelligent optimization design system of the hydraulic manifold blocks is presented based on rule-based reasoning. The key of the manifold design is the hole’s connection, and the special layout of manifold is introduced. Based on the relative position and connection relationship of the holes, special mathematic model and rule-based reasoning are proposed for the holes layout and connection design. Rule-based reasoning which is used to guide algorithm search direction is proposed according to the holes special location. Goal actuation control strategy is adapted to search a group of optimization solution which is satisfied with the connection requirement. An example of hydraulic cartridge manifold block of high-speed bar cutting machine is given. It is testified that single line net algorithm satisfies the design requirement of real time checking, the shortest connection route and minimum number of craft hole.
Performance Parameters Analysis of Vibrating Cooler
Authors: Yin Zhong Jun , Chen Bing , Zhang Lian Wan , Tian Zheng
Published: November 2010

The dynamic model of vibrating cooler was established to carry out dynamic analysis and the theoretical parameters were obtained. The dynamic data acquisition system was used to collect time domain signal, the vibrating cooler was tested and the acceleration curves of measuring points under working conditions were obtained. Analyzed the amplitude, trajectory and vibrating direction angle of the vibrating cooler and compared with design parameters so as to evaluate its performance. The results show that the design of vibrating cooler is reasonable and straight-line performance of the cooler is ideal, which verified the vibrating cooler can meet the design requirements and the production process.
Experiment Research on Tangential Dynamic Characteristics of Machined Plane Joint Interfaces
Authors: Zhang Xue Liang , Wen Shu Hua , Lan Guo Sheng , Ding Hong Qin , Zhang Zhong Yang
Published: November 2010

In this Paper, a Test Rig and a Test and Analysis System Are Designed to Research the Tangential Dynamic Characteristics of Machined Joint Interfaces. the Effects of Normal Pressure, Medium, Material, Machining Method and Roughness on the Tangential Stiffness and Damping of Joint Interfaces Are Investigated Systematically. some Important Conclusions Are Obtained.
Performance Analysis of Asymmetrical Roll Bending for Flatness Control of Cold Rolling Mill
Authors: Zhang Dian Hua , Wang Peng Fei , Zhang Wen Xue , Li Xu
Published: November 2010

When there appeared catastrophic asymmetrical flatness defects in rolling processes, especially when the incoming strip is with a wedge shape, the tilting roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting roll will lead to strip break. In order to improve the ability of cold rolling mill for asymmetrical flatness defects control, performance of the work roll asymmetrical bending as well as the intermediate roll asymmetrical bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical roll bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical roll bending is significant for asymmetrical flatness control.
The Microstructure and the Wear Resistance of the Hypoeutectic High Carbon Fe-B Cast Steel
Authors: Li Ji Wen , Zhang Guo Shang , Wei Shi Zhong
Published: November 2010

A new wear resistance material named the hypoeutectic high carbon Fe-B cast steel with fine hard carbides dispersive distributed in the matrix have been investigated. The results show that the solidified structures of high carbon Fe-B steel consist of ferrite, pearlite and boride, and borides were distributed along grain boundary in interconnected network. After heat treatment, the metallic matrix changes into martensite and retained austenite. The eutectic borides are appeared to be less continuous network and isolated particles. The increasing of the quenching temperature leads to the improvement of hardness. Quenching at 980°C, impact toughness is increased with the increasing of the tempering temperature. The optimum heat treatment is quenching at 980°C(oil cooling) and tempering at 330°C(air cooling). The wear resistance of modified high carbon Fe-B cast steel is corresponding to Cr26 alloy. The impact wear mechanism is mainly plastic deformation and fatigue spalling.
Equal Channel Angular Pressing and Torsion (ECAPT) for Densification and Strengthening Properties of Powder Sintered Materials
Authors: Li Yong Zhi , Bai Xiao Bo , Xie Yu Min , Xie Ke Min
Published: November 2010

Severe Plastic Deformation（SPD）methods are hot research techniques of preparation of bulk ultrafine-grained materials and strengthening the material properties currently .Among the various SPD methods, ECAPT that a new method of ECAP （Equal channel angular pressing） organic integrates with TE（Twist extrusion）was key introduced for the frist time ,and experimental study on ECAPT technology for deformation and densification of pure Al and Mo powder sintered materials were carried out and the results were compared with that of ECAP in this paper.The results show that there have more effective and more stronger severe plastic deformation during the process of ECAPT and it improves the ability of material’s plastic deformation and strengthens the material properties.In forming process of ECAPT after three passes,the grain size of powder sintering reduces the average 200%, and there has its nearly full density and comprehensive performance materials to improve overall performance significantly.It is confirmed that there have better comprehensive mechanical properties of strengthening materials and more stronger severe plastic deformation during the process of ECAPT contrast to the ECAP, too.
PTC Behavior and Microstructure of Zn-Ni-Ti-O Ceramics
Authors: Pu Yong Ping , Mao Yu Qin , Wei Ji Feng
Published: November 2010

Zn-Ni-Ti-O system ceramics were prepared by solid state reaction method using two different routes. The positive temperature coefficient of resistivity (PTCR) behavior and microstructure were investigated in terms of different composition and synthetic routes. It was found that using ZnO, NiO and TiO2 as the starting materials (route A), the prepared ceramics exhibited low room temperature resistivity (ρRT was ~102 Ω•cm) and inferior resistivity jump (ρmax/ρmin<50) starting at the temperature when it began to rise. However, using ZnOss (Zn0.95Ni0.05O), NiOss (Ni0.55Zn0.45O) and spinel phase (ZnNiTiO4) as starting materials (route B), the ceramics revealed ρRT >103 Ω•cm and marked resistivity jump (ρmax/ρmin was ~102) starting at ~200 °C. The microstructure showed that the ceramics prepared by route B possessed clear-cut grain boundaries but the grains of ceramics prepared by route A were irregular shape and distribution.
Study on the Thermal Stability of MUF Co-Polymerization Resin
Authors: Zheng Yun Wu , Zhu Li Bin , Gu Ji You , Zhang Yan Hua
Published: November 2010

Curing is the key to the bonding, the study indicate that: curing effect on the glue bond strength, formaldehyde emission as well as Productive Efficiency; the better curing system can ensure the Productive Efficiency in basic to decrease the FE. This paper considered the production practice, studied the curing properties of different MUF resin with TGA. The experimental result: Different curing systems, made different curing process. For A curing system, curing rate is the fastest, the degree of curing is best. Cured stability is well. While in the C curing system, Because of their poor degree of cross-linking, poly-condensation cross-linked imperfect. While, Along with the increasing of n(F):n(U1), initial decomposition temperature increased, the maximum rate of mass loss moved to higher temperature, mass loss declined, decomposition activation energy increases, aging resistance increased.
Microstructure Simulation of Aluminium Alloy Wheel Die Forging Using Cellular Automaton
Authors: Huang Shi Quan , Yi You Ping , Zhang Yu Xun
Published: November 2010

The prediction of dynamic recrystallization (DRX) plays an important role in design of hot forging process. In this work, a simulation model coupled cellular automaton (CA) with FEM was proposed to quantitatively simulate the microstructure evolution and flow stress during 7050 aluminium alloy wheel die forging. The model of dislocation density was established by isothermal compression test on Gleeble-1500. The physical fields, such as temperature, strain rate and strain, were obtained by DEFORM-3D for microstructure simulation. To refine grain size and improve uniformity, the isothermal forging parameters for 7050 aluminium alloy wheel were optimized by CA simulation. The simulation results showed that DRX percentage increased from 9.9% to 50% by using isothermal forging instead of hot die forging, while the flow stress decreased from 84MPa to 40MPa. Uniform density and small grain related with high mechanical properties were achieved via isothermal die forging process. The experiments of scaled wheel die forging were carried out on a hydraulic press with nominal working pressure 3150KN to verify simulation results. The good agreement between the simulation results and the experimental results indicate that the simulation model presented in this work can be used to predict the microstructure evolution of forging and optimization of forging process.
Improvement of Porosity of Strip Using a Scraper on the Casting by a Vertical Type High Speed Roll Caster
Authors: Nakamura Ryoji , Shiotsu Yusuke , Komeda Kosuke , Kumai Shinji , Warari Hisaki
Published: November 2010

Porosity occurred in the 5182 aluminum alloy strip cast by a vertical type high speed twin roll caster. The porosity was caused by high-roll-speed and low-roll-load. Improvement of the porosity was tried by a scraper. The scraper was mounted on the roll, and the scraper was moveable depend on the thickness of the solidified layer on the roll. The scraper scribed the semisolid layer to improve the porosity. The scraper was useful to decrease the porosity of roll cast 5182 aluminum alloy strip.
Surface and Bulk Crystallization Kinetics of Er3+ Doped Mixed Alkali Phosphate Glasses
Authors: Fang Yong Zheng , Xu Jia Yue , Wang Zhang Yong , Qian Hui Chun
Published: November 2010

DSC measurements have been carried out for the as-quenched xNa2O- (15-x)Li2O-4B2O3-11Al2O3-5BaO-65P2O5 (x=0,3.75,7.5,11.25 and 15 mol%) glasses with different particle size. Two crystallization peaks appear on the DSC curves for sample sized 90-110μm. The presence of two crystallization peaks is due to different crystallization mechanisms, surface and bulk (internal) crystallization. The X-ray diffraction measurements are also employed to investigate the crystallization of glasses. The results show that bulk crystallization is difficult to occur in the studied phosphate glasses. The effect of mixed alkali on glass thermal stability is also studied in this paper. The surface and bulk crystallization active energies are calculated according to Kissinger equation.
Integrated Design of Micro Configuration and Macro Arrangement with Scale-Coupled Effect for Maximum the Fundamental Frequency
Authors: Liu Yuan Dong , Yin Yi Hui
Published: November 2010

It is well known that structural behaviors of composite solids are determined by topology of microstructures of different sizes. In this paper a concurrent topology optimization method for integrated design of materials and structures with periodical microstructure was presented. The microstructures were assumed to be uniform in macro scale and heterogeneous in micro scale and the optimization object was to maximize the material fundamental frequency. Design variables for structure and material microstructures were defined, independently. RAMP (Rational Approximation ofMaterial Properties) was adopted to ensure clear topologies in both macro and micro scales. Design variables for structure and material microstructures were integrated into one system by using the super-element method. Influences of Representative Volume Element sizes, the microstructure configuration and macro arrangement are investigated. Numerical experiments validate the proposed method which can be used as an innovative design concept for the lightweight structures.
Surface Modification of Biomedical Magnesium Alloys by PHB
Authors: Ma Xiao Lu , Lv Yu Rong , Gao Zi Xing , Cheng Guo Xiang
Published: November 2010

Magnesium alloys are potential in biomedical materials, but their corrosion rates are high in human body fluid so that they can not be used enough time. Therefore, to improve the anti-corrosion property of the alloys is important for their application in biomedical materials. In the work, a new coating was prepared from poly (3-hydroxybutyrate) (PHB), a biopolymer used as a sustained release carrier of drugs. The effect of the PHB coating was studied by electrochemical tests, scanning electron microscope (SEM) and weight loss corresponding with the corrosion time. The result showed the sample coating PHB have a higher corrosion potential than one before coating PHB, that is, PHB coating is effective for improvement of corrosion resistant of the alloy. Moreover, the corrosion state on the surface is even by SEM, implied the corrosion rate of the PHB coating is divinable and controllable. Whereby, PHB should be suitable for anti-corrosion of magnesium alloys applying in biomedical materials.
Mid-IR and Raman Spectral Properties of Hydroxyl/Deuteroxyl Cobalt Chlorides
Authors: Liu Xiao Dong , Meng Dong Dong , Zheng Xu Guang , Hagihala Masato , Guo Qi Xin
Published: November 2010

The geometrically frustrated material-deuteroxyl cobalt chlorides Co2(OD)3Cl sample was first, to the best of our knowledge, successfully synthesized in the same single phase as the famous Co2(OH)3Cl, and their mid-infrared absorption spectra (4000-400cm–1) and Raman spectra (4000-95 cm–1) are first, to the best of our knowledge, measured respectively by FTIR spectroscopy and Micro-Raman spectroscopy to study the corresponding relationship between their spectral properties and crystal structure. Through the comparative analysis of the four spectra we definitely assign or tentatively suggest the vibration modes of hydroxyl/deuteroxyl groups in the trimeric hydrogen bond environment, (OH/D)–Co–(OH/D), and (H/D3···Cl)–Co–(Cl···H/D3). These results can be propitious to the low temperature spectral properties of Co2(OH)3Cl and Co2(OD)3Cl which must help to understand the underlying physics of their exotic geometric frustration phenomenon.
Crack Initiation and Progressive Damage of Three Gorges Granite
Authors: Zhu Ze Qi , Sheng Qian , Zhang Yong Hui , Leng Xian Lun
Published: November 2010

Based on the uniaxial and triaxial compression tests of Three Gorges granites，the crack initiation stress under different confining pressures can be obtained by studying the crack strain curves. The results show that the crack initiation stress changes at the same extent with confining pressure, and is generally located between 25% and 50% of the peak strength. Moreover, the crack initiation criteria and progressive damage model are established, and some beneficial conclusions are drawn. The tension concentration model of elliptic crack can be used to explain cracking mechanism of Three Gorges granite at relatively low confinement, and Three Gorges granite mainly occurs lateral damage in the microfracturing process and exhibits the similar damage evolutionary rule under different confining stress. The damage model can be used to describe the crack propagation process.
Experimental Investigation of the Mixed-Mode Crack Expanding in Bamboo
Authors: Zhao Jian Ting , Ma Shao Peng , Liu Huan Rong , Ren Hai Qing
Published: November 2010

Bamboo is a typical natural graded material, from the inner layer to the middle layer, and then to the outer layer. The elastic modulus is increasing gradually. The cracks grown on the inner layer and outer layer have different effects on the intensity. In this paper, the influence of the gradient distribution on the fracture behavior of the mixed-mode I and П cracks located in different layers is studied. The displacement measurement of bamboo specimens on asymmetric loading using digital speckle correlation method (DSCM) is performed and the crack tip opening displacement (COD), the stress intensity factor can be obtained. The results show that the COD of the crack in the outer layer is less than that of the crack in the inner layer, the stress intensity factor in the outer layer is greater than that of the crack in the inner layer, that means the property of the gradient distribution of bamboo has the protecting function for the static crack in the inner layer.
Creep Behaviors of Nickel-Based Single Crystal Superalloys Compact Tension Specimen at High Temperature
Authors: Wen Zhi Xun , Hou Nai Xian , Yue Zhu Feng
Published: November 2010

Based on the microstructure change and damage characteristics of single crystal, a two-state-variable crystallographic creep damage constitutive model has been developed to investigate crack growth behaviors of single crystal compact tension specimen at 760 for two crack orientations: (001)[100] and (011)[100]. Numerical simulation results show the crack-tip stress fields are dependent on crack crystallographic orientation. Observations performed on the real single crystal specimens reveals that the macroscopic crack growth path appears as zigzag wave. The creep deformation at crack tip takes place in specific slip plane, and the deflection angles of crack initiation direction from the crack plane are 45º or 135 º and 53.7ºor 127.3º in the crack orientations (001)[100] and (011)[100]. A good agreement between experimental observations and numerical results is found.
Processing Characteristic of the High-Strength Magnesium Alloy
Authors: Ruan Li Qun , Kawamura Yoshihito , Marumo Yasuo , Usumoto Akira
Published: November 2010

Mg96Zn2Y2 is a high strength magnesium alloy material developed by Mr. Kawamura in Japan. The name of this alloy is called as 'Kumadai Goukin'. The purpose of the present study is to evaluate the processing property of Mg96Zn2Y2 material. For this purpose, cylinder upsetting tests were performed. In addition, the marketing community of AZ31 magnesium alloy collates the information with the new material. We examined and compared the deformation resistance and ductility of the two materials. Furthermore, the dependence of deformation resistance and ductility of these materials to processing temperature and speed was evaluated [1],[2].
Hydrogen Embrittlement and Corrosion Fatigue Performance of Galvanized Steel Wires for High Strength Bridge Cables
Authors: Ma Ying , Ye Jian Shu , Ge Wan Guang , Lin Jing
Published: November 2010

The research results of mechanical properties, hydrogen embrittlement and corrosion fatigue of new and corroded galvanized wires which were used in cable-supported bridges were summarized. Actual tensile strength of corroded wires did not decrease with corrosion levels, whereas elongation and torsional strength decreased sharply after the zinc layer was partly depleted and the steel started to corrode. The accumulated amounts of diffusive hydrogen of corroded wires with and without induced tension were almost the same and were well below a critical value of 0.7ppm. Therefore, induced tensions of steel wires did not affect the amount of diffusive hydrogen and below the critical concentration to cause brittleness. Fatigue strength did not change only when the galvanized layer was corroded, but it significantly decreased after the steel corrosion below the galvanized layer progressed. The corrosion fatigue life under wet conditions was shorter than that under dry conditions. The endurance life of pre-split steel wires was decreased in stress amplitude and increased in load frequency under fluctuating loading and corrosive environment, the aggressive media accelerated the growth rate of the fatigue crack.
Effect of Forging Process on Microstructure and Mechanical Properties of Spray Formed Al-8.5Fe-1.3V-1.7Si Alloy
Authors: Zhang Ronɡ Hua , Zhang Yon Gan , Zhu Bao Hong
Published: November 2010

In this paper, the Al-8.5Fe-1.3V-1.7Si alloy was fabricated by spray forming and forging processes. The microstructure and mechanical properties of the alloy were investigated by means of metallographic, scanning electron microscope and tensile test. The results indicate that spray formed Al-8.5Fe-1.3V-1.7Si alloy after pressing plus can forging processes displays excellent microstructure and characterization.
Effect of Ti and Zr Deoxidation on Inclusions and Microstructure of Low Carbon Steel
Authors: Jiang Zhou Hua , Ma Jiang Hua , Zhan Dong Ping , He Ji Cheng , Yu Jin
Published: November 2010

In order to investigate the effects of Ti, Zr deoxidants on inclusions and microstructure of low carbon steel, the experiments by Ti and Zr addition were carried out. After smelting, forging, and rolling of the steel, the effects of Ti and Zr deoxidation on inclusions and steel microstructure were studied. The inclusion characteristics (size, quantity, morphology and composition) of samples were analyzed using optical microscope and scanning electron microscopy (SEM), and the grain size and density were measured. The following results were found. The diameter of most inclusions is less than 3 μm. A linear relationship exists between inclusions density and Ti content when Ti content ranges from 0.004% to 0.032%. With the increasing of the Ti content in steel, the proportion of inclusions diameter less than 0.5 μm decreases. The inclusions distribution changes a little when Ti content ranges from 0.01% to 0.03%. The typical inclusions are TiN and TiN-MxOy, with oxide core and MnS wrapper layer, and the components change with Ti content. The average grain equivalent diameter ranges from 11.8 to 15.9 μm in the experiments. The consistent linear relationship exists between grain density and the total density of the inclusions with the diameter range from 0.5 to 3 μm.