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15 February 2011, Volume 32 Issue 2 Previous Issue    Next Issue
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Output-feedback control of a class of stochastic nonlinear systems Li, Wu-Quan (1); Jing, Yuan-Wei (1); Zhang, Si-Ying (1); Zhou, Yu-Cheng (2) 2011, 32 (2):  153-156+161.  DOI: - Abstract ( 269 )   HTML   PDF (246KB) ( 590 )   For the output-feedback stabilization of a class of stochastic nonlinear systems, a stabilizing output feedback controller was designed for its corresponding nominal system via backstepping with an effective observer designed. Then, an effective coordinate transformation was introduced with an appropriate high-gain parameter chosen, and a smooth output-feedback controller was designed via the high gain homogeneous domination technique for the whole system, thus ensuring that the equilibrium at the origin of the closed-loop system is globally asymptotically stable in probability. What the process mentioned above contributes is mainly making the conditions for linear growth as often shown in earlier works more generalizable so as to enable the result to be more general. The efficiency of the output-feedback controller is verified by a numerical simulation as example. References | Related Articles | Metrics

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Intelligent control of hydrocyclone separation process Zhao, Da-Yong (1); Chai, Tian-You (1); Fu, Jun (1); Yue, Heng (1) 2011, 32 (2):  157-161.  DOI: - Abstract ( 323 )   HTML   PDF (1386KB) ( 689 )   The hydrocyclone separation process (HSP), as a two-input/three-output system with such complex characteristics as strong coupling, high nonlinearity and frequent variation of boundary conditions, is difficult to be expressed by an accurate mathematical model. An intelligent control method is therefore proposed for HSP by integrating the modeling with control process so as to combine the PI control, fuzzy control with RBR (rule-based reasoning). Then, the CAC(cascade averaging controller) based on the fuzzy control algorithm for the liquid level in pumping sump and ore feeding pressure of hydrocyclone, the control of abnormal liquid level based on RBR, the switching controller for slurry pump speed and the PI control for the ore feeding concentration by hydrocyclone are all available to implement. The application results in a large-scale domestic beneficiation plant revealed that the method proposed can stabilize the HSP effectively with particle sizing index evidently improved. References | Related Articles | Metrics

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Design of ordering strategy for procurement and supply chain system Yuan, Hua-Wei (1); Jing, Yuan-Wei (1) 2011, 32 (2):  162-164+187.  DOI: - Abstract ( 268 )   HTML   PDF (228KB) ( 652 )   To solve the problem how to meet the needs of different materials in the Baosteel procurement and supply chain system via different ordering strategies, an ordering quantity model for these materials is developed with an empirical formula set for the safety stock. In the practical application process where some probability distributions can not be accurately found, the demand and consumption of materials are forecast by the gray model. With the demand of materials forecast, the safety stock is set in the procurement and supply chain system and, with the ordering quantity model applied to different materials, the problem of ordering strategy in the procurement and supply chain system is solved. Examples show that the ordering strategy model proposed here is of robust significance in application to users. References | Related Articles | Metrics

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Generalized synchronization of a new fractional-order hyperchaotic system based on state observer Sun, Ning (1); Wang, Zhi-Liang (1) 2011, 32 (2):  165-168.  DOI: - Abstract ( 443 )   HTML   PDF (226KB) ( 657 )   Studies the generalized synchronization of a new fractional-order hyperchaotic system which is defined by the Caputo's fractional derivative according to practical requirements. For this system, a state observer is designed on the bases of pole assignment and the stability theory of a linear fractional-order system. An appropriate feedback gain matrix of the state-observer can be obtained through the pole assignment so as to realize the generalized synchronization between the arbitrary linear nonsingular transformation of the observer's state and the state of the fractional-order hyperchaotic system, thus the conventional modes of synchronization, e. g., the complete synchronization, anti-synchronization and projective synchronization are all available. Numerical simulation verified the effectiveness of the method proposed. References | Related Articles | Metrics

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Decentralized model reference adaptive control for a class of uncertain time-delay large-scale systems Zhai, Ding (1); Jin, Chao (1); Liang, Li (2); Liu, Li-Li (1) 2011, 32 (2):  169-171.  DOI: - Abstract ( 296 )   HTML   PDF (711KB) ( 786 )   A class of uncertain time-delay large-scale systems is studied by using decentralized model reference adaptive control where the reference model was selected according to the performance which the system expected, with the interaction between subsystems taken into account so as to keep the interconnected terms. The interconnections and disturbances in such uncertain large-scale systems are time-varying and uncertain. Under the conditions that the bounds of uncertainties are unknown though they come into being, the decentralized adaptive control law is given and it is proved that an entirely large-scale interconnected system is ultimately uniformly bounded by Lyapunov stability theory. References | Related Articles | Metrics

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Modeling and analysis of singular networked control systems with time-delay Liu, Li-Li (1); Zhang, Qing-Ling (1); Du, Zhao-Ping (1) 2011, 32 (2):  172-174.  DOI: - Abstract ( 305 )   HTML   PDF (951KB) ( 800 )   The modeling of singular networked control systems was discussed, and the mathematic models were developed for the different driven modes of sensors, controllers and actuators especially whether the impulse exists in the system. Then, the causality, controllability and observability were analyzed for a class of singular networked control systems with short time delay, where the sensors were clock-controlled while the controllers and actuators were both event-driven. The necessary and sufficient conditions were given for the causality, controllability and observability of singular networked control systems. References | Related Articles | Metrics

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Soft-sensing for calcining zone temperature in rotary kiln based on model migration Zhang, Li (1); Gao, Xian-Wen (1); Wang, Jie-Sheng (1); Zhao, Juan-Ping (1) 2011, 32 (2):  175-178.  DOI: - Abstract ( 378 )   HTML   PDF (1427KB) ( 887 )   The calcining zone temperature in a rotary kiln is a very important process parameter to control the kiln, but the temperature is so difficult to be measured directly and no sufficient measured data are available to soft-sensing. For the purpose of obtaining the accurate soft-sensing model in case the data are less with the temperature similarity between kiln head and calcining zone taken into consideration, the process modeling based on process similarity (PMBPS) is introduced, i. e., the rotary kiln head temperature model is developed with lots of accurately measured values involved by T-S fuzzy neural network which is trained by the chaotic hybrid learning algorithm, then the PMBPS algorithm is applied to the kiln head temperature model to correct its deviation as a model migration algorithm so as to obtain the soft-sensing model of calcining zone temperature. Simulation results verified the effectiveness of the modeling method of soft-sensing. References | Related Articles | Metrics

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Robust stability of uncertain discrete large-scale systems with time delays Xiao, Xiao-Shi (1); Mao, Zhi-Zhong (1) 2011, 32 (2):  179-182.  DOI: - Abstract ( 288 )   HTML   PDF (1575KB) ( 703 )   Discusses the robust stability of a class of discrete large-scale systems with time-varying delay and nonlinear uncertainty. Based on the Lyapunov functional method and matrix norm inequality approach, a criterion of delay-independent robust stability for the systems is proposed, and the sufficient conditions as the criterion are given in terms of a family of Lyapunov equations and algebraic inequalities for simple computation and easy check. A numerical example is given to demonstrate the correctness of the method proposed. References | Related Articles | Metrics

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A differential evolution algorithm for dynamic scheduling with variable delivery dates Liu, Li-Li (1); Wang, Shi-Yuan (1); Wang, Ding-Wei (2) 2011, 32 (2):  183-187.  DOI: - Abstract ( 333 )   HTML   PDF (1338KB) ( 643 )   Diversity loss and low optimizing efficiency are the two problems to be solved for the differential evolution (DE) algorithm in dynamic environment. A multi-population DE algorithm usually applied to the space optimization of continuous solution is proposed for the solution of dynamic scheduling problem with sequential coding, where the representative method using random keys for coding is introduced to transform the continuous position vectors into sequential coding. A self-organizing multi-population strategy is then set out to divide the population into parent population and child population, which is separated automatically from the parent one in accordance to their dynamic spatial characteristics. With the parent population in uninterrupted search of the regions where the peaks take place, the child population is assigned to exploit the useful regions further with adaptive adjustment done for its size, thus expediting the optimizing speed of the algorithm with computing resource saved. The algorithm proposed has been applied to the dynamic scheduling with variable delivery date, and a satisfactory result is gained. References | Related Articles | Metrics

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An algorithm for face accurate tracking based on analogue deviation matching Zhang, Yang (1); Ye, Shu-Fan (2); Gao, Li-Qun (1) 2011, 32 (2):  188-192.  DOI: - Abstract ( 453 )   HTML   PDF (1222KB) ( 606 )   A normalized composite index named analogue deviation was defined to describe a degree of approximation of data samples, based on the similarity and Euclidean distance coefficient. The matchability between images of the same face can be expressed via the analogue deviation of vector sets of image grayscale data. Combining the SVM face detection and tracking template updating with the analogue deviation matching of image grayscale, a new face tracking algorithm based on analogue deviation matching was proposed taking account of both the information on color values and color's spatial positions in image, thus making the algorithm more accurate. Experimental results showed that algorithm proposed can find out the best region matchable to template data in the grayscale matrix of simulated image. In addition, the algorithm is highly robust during static or dynamic face tracking because of its strong resistance to environmental interference. References | Related Articles | Metrics

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PSO-based live wire interactive image segmentation algorithm Yi, Yu-Feng (1); Gao, Li-Qun (1); Cui, Zhao-Hua (1); Shi, Sheng-Lun (2) 2011, 32 (2):  193-196+201.  DOI: - Abstract ( 647 )   HTML   PDF (333KB) ( 951 )   A PSO-based live wire interactive image segmentation algorithm was proposed to solve the problems that the objective contour is easily influenced by imaging artifacts and imaged at low computation speed. With a new cost function formulated, the gradient amplitude change function between adjacent nodes was introduced into the new cost function to reduce the interference due to imaging artifacts and improve the segmentation accuracy. To improve the implementing efficiency of the algorithm proposed, PSO was applied to finding out the shortest path between any two points in image so as to locate the objective edge, and the relevant results were compared with the typical Live Wire image segmentation algorithm based on the search by the Dijkstra algorithm. It was found that the proposed algorithm is more accurate and efficient. References | Related Articles | Metrics

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On the BGP-based bad websites address blocking system Wang, He-Xing (1); Wang, Cui-Rong (1); Yu, Ge (1) 2011, 32 (2):  197-201.  DOI: - Abstract ( 317 )   HTML   PDF (1224KB) ( 1003 )   The conventional method to prevent the bad information from overflow in Internet is slow on response with complicated procedures. A new BGP-based network address blocking system was therefore proposed to solve the problem, where a bad websites address distribution system was setup with a private AS number used as the identifier of network blocking point. With the multi-hop mechanism, the session between the bad websites address distribution system and network blocking points was implementing, then the configuration of black hole at network blocking points blocked the access to bad websites address. The deployment of the prototype system showed that after the verification of a bad network address which has been accused, the distribution system will transmit the bad network address to all blocking points in seconds so as to block the target network address quickly. The blocking system can be deployed in carrier networks to effectively prevent the bad information from its diffusion. References | Related Articles | Metrics

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A collaborative filtering approach for web QoS prediction Zhang, Li (1); Zhang, Bin (2); Huang, Li-Ping (1); Zhu, Zhi-Liang (1) 2011, 32 (2):  202-206.  DOI: - Abstract ( 335 )   HTML   PDF (1805KB) ( 610 )   Due to the different backgrounds and experiences, users often have different impressions of the same QoS though they have been served all the same. An approach to predict QoS was therefore proposed, based on not only the historical QoS data, but also the factors of environment and users' inputs. Normalizing the original data by Gauss method, a set of Web services highly similar to the target service was picked out via the similarity computation to compare the target service to be predicted with other services. Then, the blank datasheet was predicted according to the service similarity so as to compute the similarity between users for the pridiction of QoS data of users' target service. Experimental results showed that the approach proposed can improve the prediction accuracy of QoS for Web service. References | Related Articles | Metrics

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Prediction of IPv6 internet topology evolution in 2012 Yang, Bo (1); Zhao, Hai (1); Ai, Jun (1); Fu, Yao (1) 2011, 32 (2):  207-210.  DOI: - Abstract ( 260 )   HTML   PDF (1373KB) ( 573 )   Analyzing the power-law of the degree and coreness of the nodes of network and based on the evolution of Internet topology, the hierarchical model is integrated with ARIMA model so as to propose a prediction model for the evolution of IPv6 network topology. Then, the three years' data of IPv6 from January 2008 to April 2010 as authorized by CAIDA was chosen to verify the model, and the model was used to predict the characteristics of IPv6 network. The results showed that the evolution of IPv6 network follows a complex law. The prediction model is able to not only reproduce the evolution process of IPv6 network in the recent three years but also fit the IPv6 evolution in the last year. It is therefore inferred that the model can be applied to the prediction of the evolutionary trend of the IPv6 network. For example, the size of IPv6 networks will rise to around 9729 in the year 2012, and the number of links will increase to 17108. References | Related Articles | Metrics

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Analysis of change of connections on link layer in mobile wireless sensor networks Li, Da-Zhou (1); Zhao, Hai (1); Zhu, Jian (1); Zhang, Kuan (1) 2011, 32 (2):  211-214.  DOI: - Abstract ( 251 )   HTML   PDF (1232KB) ( 459 )   A key problem in dynamic wireless sensor network is the effect of moving nodes on the change of network connections. Analyzing the influencing factors on the change of the connections on the link layer of mobile wireless sensor networks, i. e., the node moving speed and network load ratio, the node moving speed in network is described efficiently with the concept of speed radius ratio so as to investigate the joint effect of the two influencing factors. Based on the in-depth study on the change of link layer connections in network and lots of data resulting from simulative tests, a conclusion is drawn that the connection changing rate increases with increasing speed radius ratio but decreases with increasing network load ratio. The conclusion provides a valuable reference for the applications in wireless sensor networks and the study on upper layer protocols. References | Related Articles | Metrics

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Prediction/optimization-based retransmission scheme over multipath network Cai, Ling (1); Wang, Jin-Kuan (1); Wei, Yong-Tao (1) 2011, 32 (2):  215-218.  DOI: - Abstract ( 311 )   HTML   PDF (1101KB) ( 789 )   Multipath routing is an effective technique to improve the reliability and robustness of Internet, while what strategy should be taken by the routing data plane as the grounds for data retransmission is the core problem in multipath routing. To solve the problem that the Internet traffic in many applications is so sensitive to the packet loss rate, a linear smoothing process is used to predict the packet loss rate in multipath network, based on the prediction practice in combination with the theory of optimization. Then, the predicted packet loss rate is taken as the precondition for PSO so as to take the optimal solution which makes the system average packet loss rate minimal as the grounds for the retransmission ratio of multipath data. Simulation results demonstrated that the proposed scheme is available to decrease the packet loss rate in multipath network more efficiently than other techniques such as the shortest path routing or equal splitting among multipath routings. References | Related Articles | Metrics

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An inframarginal-analysis-based resource allocation method in distributed computing environment Wang, En-Ze (1); Qiao, Jian-Zhong (1); Lin, Shu-Kuan (1) 2011, 32 (2):  219-222+231.  DOI: - Abstract ( 258 )   HTML   PDF (182KB) ( 887 )   A resource allocation method based on inframarginal analysis in distributed computing environment is presented to describe the resource allocation framework based on its comparative advantage, which maximizes the system utility by the global balance resulting from corner analysis, with the IRD(inframarginal-analysis-based resource allocation model for distributed computing) model for free transaction and IRDL(IRD limited) model for transaction limitation both developed. Differentiating from the neoclassical economic theory which studies how to improve the resource utilization ratio, the new classical economic theory studies how to decrease the resource scarcity through the division of labor so as to achieve the Pareto Optimality entirely by regulating the network dynamically. Simulation results showed that both the models developed are effective and rational though the IRD model is more suitable for the distributed computing environment. References | Related Articles | Metrics

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An image sonification method based on lifting wavelet transform Tian, Ya-Nan (1); Wang, Xu (1) 2011, 32 (2):  223-226.  DOI: - Abstract ( 442 )   HTML   PDF (794KB) ( 635 )   In the conventional image sonification method the mapping features selected in the space domain and the simple sound coding make the blind difficult to understand such a sound. A method based on the transform domain is therefore presented, where the low frequency coefficients of wavelet transform are mapped into the frequency and sound length so as to represent the image in electronic music. Experimental results showed that the blind is able to understand the images mapped into the auditory representation. Moreover, the sound is pleasing to ear and enjoyable. References | Related Articles | Metrics

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Study on the formability and surface ridging of a 21%Cr ferritic stainless steel Zhang, Chi (1); Liu, Zhen-Yu (1); Dong, Wen-Bu (2); Wang, Guo-Dong (1) 2011, 32 (2):  227-231.  DOI: - Abstract ( 334 )   HTML   PDF (1496KB) ( 732 )   The effects of annealing after hot rolling and lubrication during cold rolling on the texture and grain colonies of a 21%Cr ferritic stainless steel were investigated. The results revealed that the grain colonies are obvious at the central layer of the final sheet with incomplete recrystallization during hot rolling and annealing, which having the high through-thickness texture gradient, thus causing the severe surface ridging and planar anisotropy in its forming process. And the through-thickness texture gradient became higher with lower intensity of γ-fiber texture in the final sheet if no lubrication was done during cold rolling in comparison to the sheet which was cold rolled with lubrication, thus causing the deterioration of the formability of the sheet. The way to make the formability better and the surface ridging resistance higher simultaneously is to ensure the complete recrystallization through proper annealing after hot rolling and the full lubrication during cold rolling. References | Related Articles | Metrics

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Texture evolution of Cr17 ferritic stainless steel produced by thin strip casting Liu, Hai-Tao (1); Cao, Guang-Ming (1); Liu, Zhen-Yu (1); Wang, Guo-Dong (1) 2011, 32 (2):  232-235+240.  DOI: - Abstract ( 310 )   HTML   PDF (1047KB) ( 487 )   The Cr17 ferritic stainless steel specimens of different initial microstructures were produced by thin strip casting and investigated comparatively for their texture evolution via the same cold rolling and annealing processes. The results showed that the texture evolution closely relates to the initial microstructure and texture of the cast strips. The cast strip with columnar crystals presents clearly the <001>//ND fiber texture, while the cast strip with equiaxed crystals presents the weak and nearly random texture. Then, after cold rolling, the mild α-fiber texture and homogeneous γ-fiber texture form in both the two types of cast strips, among which the latter shows much stronger α-fiber and γ-fiber textures than the former. After the recrystallization annealing, both the two types of cast strips form the homogeneous γ-fiber recrystallization texture which is clearly stronger in the latter than in the former. References | Related Articles | Metrics

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Effect of hot rolling process on deep drawability of 409L ferritic stainless steel Xie, Sheng-Tao (1); Liu, Zhen-Yu (1); Fang, Yuan (2); Wang, Zhe (2) 2011, 32 (2):  236-240.  DOI: - Abstract ( 380 )   HTML   PDF (1566KB) ( 769 )   Continuous-casting slabs with pure columnar grains of 409L ferritic stainless steel were hot rolled at different finishing temperatures (FT), i. e. the conventional hot rolling was transformed into warm rolling, then the same subsequent process was conducted. The results showed that the finished sheet rolled at lower FT has greater rm value and smaller Δr value. The decreased FT causes some variations in microstructural evolution as follows. In either hot or cold rolled sheets, the grain boundaries and in-grain shear bands increase to refine and harden the deformed microstructure, especially the coarse banded grains around mid-thickness layer. Then the nucleation sites due to recrystallization during annealing increase so as to refine and homogenize the annealed microstructure. Meanwhile, the textural evolution thus varies, such as the texture after hot rolling and annealing moves from {001~114}<110> to the regions with greater φ1 and Φ angles; the texture peak after cold rolling shifts from {001}<110> to {335}<110>; the γ-fiber texture after cold rolling and annealing increases and the peak shifts from {334}<483> to {111}<112>, while the {001~114}<110> and (0°<Φ<35°, φ1&asyum;25°) textures decrease. References | Related Articles | Metrics

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Microstructure and mechanical properties of HSLA wear-resistant steel NM400 Cao, Yi (1); Wang, Zhao-Dong (1); Wu, Di (1); Zhang, Ti (2) 2011, 32 (2):  241-244.  DOI: - Abstract ( 606 )   HTML   PDF (1341KB) ( 895 )   The low-alloy and low cost wear-resistant HSLA NM400 steel plate with high toughness was developed by Ti-Cr-B micro alloying, then direct rolling at austenite recrystallization zone with low-temperature tempering after quenching. Its mechanical properties, microstructure, fracture morphology and precipitates were tested and investigated by means of optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the microstructure of specimens is mainly composed of the high-density dislocated lath martensites with carbides distributed on them. The tensile strength≥1400 MPa, the surface hardness≥HV450 and impact toughness at -40°C>60 J. With a good hardenability, the steel has a uniform hardness distribution in thickness direction. In addition to the solid solution hardening and grain refinement, a considerable number of the high-density dislocations and Ti(C, N) nano-precipitates play an effective role in hardening. It was found by SEM and EDS that the brittle second-phase particles in fracture dimples are mainly of MnS and Al2O3, whose biggest size is about 2 μm. References | Related Articles | Metrics

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Effects of cross shear rolling on texture of aluminum foil for high voltage electrolytic capacitor Wang, Lei (1); Zhai, Xin-Sheng (1); Liu, Yang (1); Zuo, Liang (1) 2011, 32 (2):  245-249.  DOI: - Abstract ( 372 )   HTML   PDF (747KB) ( 514 )   High-purity aluminum foils were obtained by cross shear cold rolling with different parameters, and the effects of rolling parameters on the as-rolled textures in aluminum foils were investigated. Compared with the symmetrically rolled aluminum foils, six kinds of textures were found in cross shear rolled foils whose volume fraction and distribution are different from the former because of the effect of cross shear area. On the whole, the content of textures formed on the slow roller side is higher than that on the fast roller side. Both the S{123}<634> and C{112}<111> textures have the same evolution trends, as well as both the {001}<100> cube texture and the {001}<110> rotated cube texture. The content of Goss texture is lower and insensitive to either the fast or slow roller, the reduction and the speed ratio, while the volume fraction of texture is sensitive to the speed ratio and the content of cold rolled texture can be increased through adjusting the speed ratio and reduction on the final pass. It was found that the content of cold-rolled textures which is higher than that by symmetric rolling can be obtained if the speed ratio is 1.06 or 1.13. References | Related Articles | Metrics

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Development of an ultra-low carbon bainitic steel with resistance to marine corrosion Zhang, Si-Xun (1); Cui, Wen-Fang (1); Dong, Jie (2); Liu, Chun-Ming (1) 2011, 32 (2):  250-253.  DOI: - Abstract ( 302 )   HTML   PDF (1548KB) ( 595 )   The microstructure, mechanical properties and marine corrosion resistance of hot-rolled ultra-low-carbon phosphorus-bearing bainitic steel sections were investigated so as to develop a steel specially used in sea water with its high toughness and resistance to marine corrosion. The results showed that adding 0.09wt% P in the steel can provide strong solution strengthening with weak effect on impact toughness within the temperature range from room temperature to -40°C. The fact is attributed to that P segregation at austenite grain boundaries is inhibited due to the competition between C, B and P atoms, thus weakening the cold brittleness caused by P atoms. Compared with the ultra-low-carbon bainitic steels with or without P, the corrosion rate of the ultra-low-carbon bainitic steel with high P content fully submerged in 3.5%NaCl solution decreases obviously. The complex effect of Cu and P elements promotes the formation of a dense inner rust layer to resist the further penetration of Cl- in the solution. References | Related Articles | Metrics

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First principle study on electronic structure and optical phonon properties of ZrB2 Yu, Liang (1); Ru, Hong-Qiang (1); Yue, Xin-Yan (1); Li, Jing-Yang (1) 2011, 32 (2):  254-257.  DOI: - Abstract ( 299 )   HTML   PDF (1179KB) ( 797 )   The electronic structure and optical and lattice dynamic properties of ZrB2 crystal were calculated with the first principle theory. It was shown that ZrB2 has a metallic characteristic as indicated by the band structure, and the conduction bands are mainly composed of antibonding states of B2p and Zr 4d. On the B plane the σ-bonds are formed by the hybridization of 2 s and 2p orbital, while the pz orbital singly forms a delocalized π bond. These states are directly related to the optical transitions as shown in absorption spectrum. Population analysis clearly showed that a similar charge transfer mechanism from 4d of Zr to 2pz of B occurs in ZrB2 as well as in MgB2. Lattice dynamical results revealed that the vibrational modes which located at B hexagonal plane are made up of high frequency part in phonon spectrum. The prediction of ZrB2 Debye temperature should be 59.14 at 0 K according to the results of phonon. References | Related Articles | Metrics

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On the characteristics of pulsed electromagnetic force: Solidification experiment Hua, Jun-Shan (1); Zhang, Yong-Jie (1); Wang, En-Gang (1); He, Ji-Cheng (1) 2011, 32 (2):  258-261.  DOI: - Abstract ( 319 )   HTML   PDF (1720KB) ( 569 )   With the low-melting-point Wood's metal used, how the PMF (pulsed magnetic field) affects the fluctuation behavior of melt meniscus in PMF was investigated, where the melt was stirred with the peripheral electromagnetic force to form a vertex, while the radial electromagnetic force formed a liquid cylinder and vertex at the central part of melt if the force played a role of compression and tension, respectively. Moreover, the Sn-20wt% Pb alloy was applied to investigating the effect of the PMF on the quality of billet. The results showed that the microstructure of the alloy is obviously refined with the surface quality of billet improved greatly. Also, under the experimental conditions, when the pulsed discharge frequency is 3.9 or 6.6 Hz, a resonance occurs on the surface of molten metal so as to accelerate the flowability in the melt, thus enhancing the grain refining effect of the PMF. References | Related Articles | Metrics

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Effects of forming pressure and doping on the properties of Na1.4Co2O4-based materials Li, Ying (1); Ma, Bei-Yue (1); Jiang, Mao-Fa (1); Wang, Zhen-Ming (2) 2011, 32 (2):  262-265.  DOI: - Abstract ( 303 )   HTML   PDF (1180KB) ( 610 )   Na1.4Co2O4-based thermoelectric materials were prepared by sol-gel method, where the Na-site doping was done separately with Sr and Li in different amounts of 0.1, 0.2, 0.3 and 0.4. The effects of forming pressure and doping on the thermoelectric properties of the materials were investigated, such as the electric conductivity, Seebeck coefficient and power factor. The phase composition of the materials was analyzed by XRD. The results showed that the principal crystalline phase of the prepared Sr/Li-doped Na1.4Co2O4-based materials is γ-Na1.4Co2O4. The electric conductivity, Seebeck coefficient and power factor of the materials can all be increased obviously by increasing the forming pressure and Li-doping. When the doping amount of Li is 0.4, the power factor of the materials prepared under 310 MPa comes up to 7.44 mW·m-1·K-2, which is much higher than that of the materials without doping. The thermoelectric properties of Na1.4Co2O4-based materials can also be improved to a certain extent by Sr-doping in proper amount. References | Related Articles | Metrics

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Modeling of flow, temperature and concentration fields in the pusher-type slab reheating furnace Zhang, Wei-Jun (1); Wang, Fang (1); Qi, Feng-Sheng (1); Li, Bao-Kuan (1) 2011, 32 (2):  266-269+304.  DOI: - Abstract ( 276 )   HTML   PDF (1688KB) ( 695 )   A mathematical model of gas flow, combustion and heat transfer in the pusher-type slab reheating furnace was developed with the commercial CFD software Fluent to compute the flow and temperature fields and the concentration distribution of the reactants/products from combustion. Numerical results showed that the average temperature of furnace will come up to 1300°C when the temperatures of preheated air and coal gas are 350°C and 50°C, respectively. Thus, it is available to meet the requirement for slab's reheated temperature. The recirculation flow due to the complex geometry of furnace, is found obviously, and the combustion air preheating can raise the gas temperature in furnace efficiently so as to improve the furnace's thermal efficiency especially during full combustion. Such results may be taken as important reference for the optimal design and operation of reheating furnaces. References | Related Articles | Metrics

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On the multi-objective optimal model of blast furnace iron-making process and its application Zhang, Qi (1); Yao, Tong-Hui (1); Cai, Jiu-Ju (1); Shen, Feng-Man (1) 2011, 32 (2):  270-273.  DOI: - Abstract ( 782 )   HTML   PDF (834KB) ( 1197 )   Based on the conservation of matter and energy in blast furnace iron-making process and the multi-objective optimization method, a mathematical model was developed with the energy consumption, cost and CO2 emission taken as objectives, and it was applied to the No.1 blast furnace in a certain iron and steel complex. By programming and comparing the optimized results with the real data obtained from production, the model was verified correct. The optimization results showed that all the energy consumption, production cost and CO2 emission decreased to the different degrees. Meanwhile, the effects of such factors as coke ratio, coal ratio and sinter grade on the blast furnace iron-making process were analyzed by the model, and some measures are suggested to take for energy saving, cost decreasing and emission reducing. References | Related Articles | Metrics

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Study on denoising effect of sound barriers made from closed-cell aluminum foam Liang, Li-Si (1); Yao, Guang-Chun (1); Mu, Yong-Liang (1); Wang, Lei (1) 2011, 32 (2):  274-276.  DOI: - Abstract ( 388 )   HTML   PDF (823KB) ( 713 )   The denoising effect of the sound barriers made from closed-cell aluminum foam was investigated taking some sections of the sound barriers located nearby the Zhulin Overcross of the East-West expressway in Shenyang City as examples, where the sound pressure level of noise was measured with spectrum analysis before and after setting the sound barriers there. The denoising effect of closed-cell aluminum foam was evaluated via the insertion loss calculated for such sound barriers. A comparative denoising analysis of sound barrier was made between the closed-cell aluminum foam and conventional window shutters, and the results showed that the denoising effect of the former is superior to that of the latter, especially in the highly-noisy frequency band from 20 to 630?Hz beside the expressway. References | Related Articles | Metrics

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Preparation of aluminum foam sandwich panels by powder-filled tube rolling Song, Bin-Na (1); Zu, Guo-Yin (1); Yao, Guang-Chun (1); Guan, Zhi-Hao (1) 2011, 32 (2):  277-280.  DOI: - Abstract ( 312 )   HTML   PDF (1746KB) ( 810 )   Aluminum foam sandwich(AFS) panels were successfully prepared by the powder-filled tube rolling process we developed with the commercial AlSi12 alloy, Mg and TiH2 powder used as raw materials, and the precursors prepared by such a process were systematically compared with that by the composite rolling process in macro-morphology, interfacial bonding and foam structure via a scanner with a resolution 300 dpi, SEM and micro-hardometer. The results showed that the aluminum foam panels prepared in this way can prevented them from crack propagation effectively and keep their complete shape with uniform compactness, thus providing the effective bonding between panels and core material. In the finished aluminum foam sandwich panels the foaming structures are complete and uniformly distributed. References | Related Articles | Metrics

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Recognition and tracking method based on image of real-time and high-speed bar Wang, Hong (1); Guo, Fan (1) 2011, 32 (2):  281-284.  DOI: - Abstract ( 378 )   HTML   PDF (1407KB) ( 870 )   It is difficult to count the bar sections moving at high speed on production line. To solve the problem, the line scanning camera is utilized to acquire the images of moving bars so as to recognize the centroid coordinates of the bars' ends and compute their area with a Blob algorithm, and a heuristic tracking algorithm is developed to track the moving bars' ends in relation to the interframe data. A hardware/software system is therefore developed for real-time recognition and tracking of the bars moving at high speed. First, hardware platform is set up and the system's parameters are determined. Second, the software system is developed on the basis of Visual Studio 2005. The experimental results showed that the system can well count bars moving at high speed on production line, with a counting accuracy near to 100% and a recognizing time in millisecond. References | Related Articles | Metrics

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Numerical simulation analysis of formation of fluid film in the process of oil mist spraying against the metal plate Zhang, Zhi-Wei (1); Wang, Chang-Zhou (1); Song, Jin-Chun (1); Chen, Jian-Wen (1) 2011, 32 (2):  285-287.  DOI: - Abstract ( 309 )   HTML   PDF (1482KB) ( 586 )   The factors which affect the oil film formation when the oil mist is spraying against the metal plate were studied via a numerical simulation with the software FLUENT, then the contour maps of oil film thickness were plotted. In the simulation the spray speeds were 30, 80, 100 and 120 m/s; the oil drop sizes were 3, 5, 7 and 10 μm; and the spraying distances were 50 and 65 mm. The results showed that the oil film thickness and film forming ratio both decrease with increasing spraying distance, and both are comparatively perfect when the spraying distance is 50 mm with the spray speed 80 m/s. Meanwhile, both become bigger when the oil drop size is about 5 μm. References | Related Articles | Metrics

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Decomposition model and empirical study on per capita EEF in Liaoning Province Yue, Qiang (1); Li, Zhi-Wei (1); Wang, Tong (2); Shi, Yu-Min (2) 2011, 32 (2):  288-291.  DOI: - Abstract ( 331 )   HTML   PDF (444KB) ( 503 )   An EF (ecological footprint) model was used to calculate the per capita EEF (energy ecological footprint), which increased from 1.753 to 3.107 hm2 in the period from 1999 to 2008 in Liaoning province, while the EF was in the range from 2.847 to 4.729 hm2. The results showed that EEF was over 60% of EF, and that the ecological pressure owing to energy consumption increased gradually. A per capita EEF decomposition model was developed and applied to the empirical analysis of the calculated results of EEF, and it was found that the contributive effects of the intensity and structure of energy on the decreasing ecological pressure is unable to offset the ecological hazard due to economic development, thus resulting in the increasing trend of per capita EEF, especially after the year 2003. Some measures are therefore suggested to take to decrease the per capita EEF. References | Related Articles | Metrics

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An empirical research on the effect of CSR on CFP - Based on listed companies in China Zhang, Lan-Xia (1); Yuan, Dong-Nan (2); Niu, Dan (1); Jin, Yue (1) 2011, 32 (2):  292-296.  DOI: - Abstract ( 573 )   HTML   PDF (928KB) ( 3272 )   Based on the theory of stakeholders, a model of the effect of corporate social responsibility(CSR) on corporate financial performance(CFP) was developed with ROA (return on assets) as the dependent variable, and the scale, trade and ownership of a company as the controlling variables, and some hypotheses were suggested. To verify the model and hypotheses, the data of 1000 listed companies in China from 2003 to 2008 was used for statistical analysis. The results indicated that those companies didn't pay close attention to their downstream customers and governments though they took well the CSR for their creditors, employees and upstream suppliers. In addition, the scale of a company and what trade it was making affect CFP to a certain extent, while the ownership affected it unobtrusively. The current CFP of those companies was positively affected obviously by how they did in CSR currently and previously. Meanwhile, it was found there was a multicollinearity between the CSRs in different periods, and the influences of CSR on current CFP of China's listed companies on different scales and in different trades were not the same. References | Related Articles | Metrics

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Bilateral matching model of demand and supply in knowledge service Jia, Lu (1); Fan, Zhi-Ping (1); Shen, Kai (1); Xu, Bao-Fu (2) 2011, 32 (2):  297-301.  DOI: - Abstract ( 942 )   HTML   PDF (1605KB) ( 1947 )   Aiming at the bilateral matching of the demand and supply in knowledge service, how to develop a relevant model was studied on the bases of multi-index evaluation information and its processing. With the maximum satisfaction, given to both knowledge demand and supply, and the maximization of intermediary interests in knowledge service taken as the objectives, a multi-objective bilateral matching optimization model was developed. Furthermore, the weighted sum based on membership functions was used to transform the multiobjective optimization model into a single objective one to which the solution offered the bilateral matching results. A numerical example is given to illustrate the feasibility and validity of the bilateral matching model thus proposed. References | Related Articles | Metrics

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Optimal decision on cold-chain storage of goods Liu, Bao-Zheng (1); Wang, Ding-Wei (1) 2011, 32 (2):  302-304.  DOI: - Abstract ( 243 )   HTML   PDF (725KB) ( 636 )   Assuming that the inventory costs in cold chain increase linearly and time-dependently with mass loss and that the selling prices of refrigerated goods rise slowly and come up to the peak at a certain time, then the prices are going down slowly, an optimal model is developed for storage/sales of refrigerated goods, where the objective is maximizing the profits after the stocks have all been sold out with the selling time taken as a decision variable. The conditional extreme value method of nonlinear programming is used to solve the model. Simulation results verified the feasibility and effectiveness of the model by a numerical example. References | Related Articles | Metrics