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15 June 2008, Volume 29 Issue 6 Previous Issue    Next Issue
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Intelligently optimal index setting for flotation process by CBR Geng, Zeng-Xian (1); Chai, Tian-You (1) 2008, 29 (6):  761-764.  DOI: - Abstract ( 253 )   HTML   PDF (338KB) ( 816 )   In the flotation process it is hard to develop an accurate mathematical model for both concentrate grade and tailing grade which characterize the key technical indices. However, it is also hard to control efficiently the process by conventional methods. A new way is therefore recommended combining the case-based reasoning (CBR) with conventional control methods, i.e. the intelligently optimal index setting by CBR. In this way the experience of flotation process can be grasped more profoundly from lots of historical process data so as to build a case database which summaries typical operation conditions. The retrieval, reuse, revision and store of those cases are discussed in CBR. The intelligently optimal index setting model can update automatically all setpoints in every control loop so as to avoid the subjectivity and randomness due to arbitrary manual control setting. This approach has been successfully applied to a flotation process in a mineral processing plant with its effectiveness actually proved. References | Related Articles | Metrics

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Object-oriented application of image processing system in complex industrial process Sun, Peng (1); Zhou, Xiao-Jie (2); Chai, Tian-You (1) 2008, 29 (6):  765-768.  DOI: - Abstract ( 250 )   HTML   PDF (499KB) ( 635 )   According to the complexity of variation in a complex industrial process, the current measurement has dropped behind. To solve the problem, an object-oriented architecture of image processing system is proposed for complex industrial process, which combines the computer techniques with image process techniques. Taking account of its versatility and object-oriented characteristic, the architecture includes video monitoring module, integrated module of image processing algorithm and intelligent recognition module of working conditions, thus embodying what the software are pursuing structured system design and multiplexing software. For example, the architecture has been applied to develop an image processing system so as to recognize the burning zone in rotary kiln for alumina production as a typical complex industrial process, and the good results has been verified. References | Related Articles | Metrics

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Output synchronization of complex network Wang, Li-Fu (1); Jing, Yuan-Wei (1); Kong, Zhi (1) 2008, 29 (6):  769-772.  DOI: - Abstract ( 200 )   HTML   PDF (1786KB) ( 632 )   State synchronization is an important direction in the complex network field. However, the actual state of system is often unable to observe, and sometimes only part but not all of states is needed to make the synchronization to come true. Therefore, a new complex network model with output available is proposed as an extension of original complex network model. Then, according to the output matrix which is either singular or nonsingular, the stability of the output synchronization of complex network is analyzed and some sufficient conditions are given to it in form of lemma. Furthermore, the conditions for stability in case the output is synchronous but the state is asynchronous are studied, and an example is given to illustrate that the output synchronization is available even if the conditions for state synchronization is unsatisfied. The results reveal the significance of output synchronization in complex network systems. References | Related Articles | Metrics

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Sliding mode control for a class of uncertain hybrid systems with Markov jumping parameters He, You-Guo (1); Jing, Yuan-Wei (1); Jiang, Nan (1) 2008, 29 (6):  773-776.  DOI: - Abstract ( 211 )   HTML   PDF (1883KB) ( 549 )   For a class of uncertain hybrid systems with Markov jumping parameters, the sliding mode controller is designed on the basis of sliding mode control theory. On the assumptions that the system uncertainties are matched and also mismatched, the sufficient conditions are proposed respectively via LMIs (linear matrix inequalities) to guarantee the mean exponential stability of reduced-order sliding mode system. Corresponding to the two different system uncertainties, the sliding mode control strategy is designed, which is proved able to guarantee that the system trajectory reach the sliding surface in a finite time interval and keep up here thereafter. Simulation results demonstrate that the proposed controllers have good stability and robustness for uncertain hybrid linear Markov jumping systems. References | Related Articles | Metrics

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Sliding mode control of uncertain time-varying linear systems and its application to network congestion Qian, Xiao-Long (1); Zheng, Yan (1); Ren, Tao (1); Jing, Yuan-Wei (1) 2008, 29 (6):  777-781.  DOI: - Abstract ( 256 )   HTML   PDF (288KB) ( 480 )   A design approach to robust stabilization based on sliding mode control (SMC) is presented for a class of uncertain time-varying linear systems. For the systems with mismatched uncertainty, the design of robust sliding surface is given. On the basis of LMI technique, then the designing approaches to sliding mode control law are given separately for the systems with matched and mismatched uncertainties. How the proposed algorithm is applied to TCP congestion control is discussed, and compared to other ones via simulation and the results showed its validity and advantages. References | Related Articles | Metrics

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Multi-criteria optimization based on chaos ant colony algorithm for secondary cooling parameters in continuous casting Ji, Zhen-Ping (1); Ma, Jiao-Cheng (1); Xie, Zhi (1); Wang, Can-Rong (2) 2008, 29 (6):  782-785+806.  DOI: - Abstract ( 257 )   HTML   PDF (251KB) ( 659 )   A method based on CACO (chaos ant colony optimization) algorithm and 2-D solidification and heat transfer model was presented to optimize the water distribution parameters in secondary cooling for continuous casting-a multi-criteria optimization problem. The solidification and heat transfer model introducing volume control method was mainly used to simulate the continuous casting process, so as to investigate the surface temperature distribution of strands and characters of parameters' search space, while the CACO algorithm was used to solve the optimization problem of water distribution parameters in secondary cooling. Characterized by the chaotic and self-organization behavior in ants' foraging process, the algorithm rises above such defects of conventional ant colony algorithm as slow convergence rate, easy to stagnate, and low ability in global search. CACO thus shows the superiority in both convergence and robustness when solving multi-criteria optimization problems. The proposed method in application for the optimization of secondary cooling parameters resulted in highly improved quality of CC billet. References | Related Articles | Metrics

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Application of SVM to image pre-processing of injection-molding for plastic products Lu, Zhe (1); Wang, Fu-Li (1); Chang, Yu-Qing (1); Sun, Tian-Yu (1) 2008, 29 (6):  786-789.  DOI: - Abstract ( 226 )   HTML   PDF (469KB) ( 728 )   Analyzing the problems found in the conventional median filters applied to the image pre-processing of injection-molding for plastic products, a novel multi-stage median filter is proposed to suit well the images plastic products. By the training of a SVM-based sorter, the type of pixels in image can be distinguished from each other so as to enable the new filter to choose properly a filtering algorithm in accordance to the type of pixels. In this way the SVM-based multi-stage median filter offers an excellent capability for edge detail protection with noise suppressed efficiently, thus satisfying the requirements of the image pre-processing of plastic products. Simulation tests have verified the effectiveness of the new filter. References | Related Articles | Metrics

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Design of fire-alarm controller based on ColdFire micro-processor Zhang, Yun-Zhou (1); Wu, Cheng-Dong (1); Xue, Ding-Yu (1); Wang, Hong-Ri (2) 2008, 29 (6):  790-793.  DOI: - Abstract ( 362 )   HTML   PDF (466KB) ( 1146 )   To improve the processing ability and response speed of a distributed fire-alarm system, an advanced 32-bit microprocessor MCF5282 is introduced in the design of the main controller of the system. Describing the system architecture and design of extension circuit of hardware interface, the system information flowchart and conceptual design of software are given in detail. The system can implement the complex on-line logical computation with its high intelligence and real-time response ability. Practical applications proved that the introducing of the high-performance microprocessor into the fire alarm controller greatly improved its quality and capability for fire control. References | Related Articles | Metrics

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Optimization algorithm based on immune evolutionary strategy for neural network Li, Hong-Ru (1); Wang, Xiao-Nan (2); Gao, Tong (1) 2008, 29 (6):  794-797.  DOI: - Abstract ( 237 )   HTML   PDF (156KB) ( 761 )   The researches on neural network ignored the closely related connection between its architecture and the weighted value for years, but mainly focused on their optimization. A neural evolution algorithm based on immune-evolution strategy is therefore proposed introducing the concentration/memory mechanism of immune system into evolutionary strategy, which can optimize simultaneously both the topological structure of network and weighted value for connection. Furthermore, the algorithm introduces the Cauchy operator instead of Gauss operator to obtain better global convergence. Theoretical analysis and simulation results both show that the algorithm can retain the population diversity, and avoid premature convergence with better global convergence as well as the ability to learn faster to learn the architecture and the weighted value of network. References | Related Articles | Metrics

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Application of feed forward-cascade control in control system of elevator door Bian, Chun-Yuan (1); Zheng, Xiang-Wu (1); Ren, Shuang-Yan (2); Man, Yong-Kui (1) 2008, 29 (6):  798-801.  DOI: - Abstract ( 281 )   HTML   PDF (373KB) ( 857 )   To solve the problem of that the faults occurred frequently in conventional control system of an elevator door, a self-restraining control scheme is proposed for those faults, based on the theory of feed forward-cascade control. It means that the feed forward control is introduced in the double close-loop control system of speed and current. Describing the global structure and working principle of the control system, the system hardware configuration and design of softwares are developed with the DSP (digital signal processor) TMS320LF2407 taken as core element. A simple optoelectronic encoder is introduced in the system to detect rotor position, thus reducing 4 bistable switches to decrease cost and maintenance jobs. Testing results showed that by the control system designed the rate of door faults is reduced with high stability and precision provided to meet the requirements of control performance for elevator door. References | Related Articles | Metrics

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Key management mechanism of secure multicast based on EBS in ad hoc network Hu, Xian-Wei (1); Chen, Xu (1); Xu, Jian (1); Zhang, Bin (1) 2008, 29 (6):  802-806.  DOI: - Abstract ( 243 )   HTML   PDF (323KB) ( 624 )   To solve the security problem in ad hoc network, a new multicast key management scheme in ad hoc environment is given as a better solution to the generation, distribution and management of dynamic members of cipher keys. Introducing the key management mechanism of secure multicast under the cluster framework of two-level management pattern, an EBS-based multicast key management protocol is put forward to assist the transmission of group communication messages by virtue of karnaugh map. Besides meeting the security requirements, the number of keys to be stored in each and every node and the communication costs required for group key updating in the key management mechanism are both much less than those of other mechanisms. References | Related Articles | Metrics

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3D rapid segmentation of pulmonary vessel and feature extraction through threshold level set Gao, Qi-Xin (1); Yu, Yang (1); Zhao, Da-Zhe (2); Liu, Ji-Ren (1) 2008, 29 (6):  807-810.  DOI: - Abstract ( 266 )   HTML   PDF (412KB) ( 971 )   The segmentation of pulmonary vessel is a challenging problem because of its tiny vessel, noisy CT image and blurred boundary. A method based on threshold level-set is therefore proposed for the 3-D segmentation of pulmonary vessel, which introduces the geometric contour-varying models instead of parametric contour-varying ones. As a result, this method is available to solve the inaccuracy of blurred boundary of the pulmonary vessel by determining the range of threshold of the position of pulmonary vessel and its distribution in accordance to anatomical structure. Thus, the segmentation of pulmonary vessel can be done more accurately. In addition, a judging scheme of branching node of pulmonary vessel tree is proposed on level-set basis. References | Related Articles | Metrics

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Implementation of trouble-shooting in hydropower simulation system by rule engine Zhao, Hai (1); Han, Xu-Dong (1); Song, Chun-He (1); Zhu, Peng (2) 2008, 29 (6):  811-814.  DOI: - Abstract ( 254 )   HTML   PDF (288KB) ( 658 )   There is a great deal of causal logic in trouble-shooting programs of conventional hydropower simulation system, in which the relations are so complicated that the programs are difficult to maintain and modify. The Rule Engine technique is thus introduced into trouble-shooting process of hydropower simulation system, i.e. the open source Rule Engine Drools is introduced to rewrite the trouble setting program so as to reduce its logical structure. A series of tests are then conducted to the modules relevant to the trouble-shooting programs in coach and trainee systems. Compared with the 1.0 version of the Fengman hydropower simulation system, the results show that both the executing time and number of trouble codes decrease in the 2.0 version in which the Rule Engine technique has been introduced, and the codes are easier to maintain by professional technical personnel so as to save R and D cost. References | Related Articles | Metrics

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Application of genetic algorithm to deployment of multiple sink nodes in WSNs Xu, Jiu-Qiang (1); Bai, Da-Zhi (1); Luo, Ding-Ding (1); Zhao, Hai (1) 2008, 29 (6):  815-818.  DOI: - Abstract ( 350 )   HTML   PDF (270KB) ( 607 )   With the WSN constrained by limited resources and energy for long, the deployment algorithm of sink nodes has become a key problem to WSN. However, the relevant existing algorithms have actually not been taking account of that the service provided by sink nodes often failed due to limited resources or the problems of wireless link. A deployment model of P-medians of multiple sink nodes is thus proposed with the computational solution given to the deployment model of the location theory and at the same time uses the genetic algorithm computing model of sink nodes which belongs to the NP-completeness problem. The computational accuracy and efficiency of the algorithm are also analyzed. The simulation results indicate that the deployment policy based on genetic algorithm can reduce the energy consumption of WSN efficiently so as to improve the efficiency of network service and prolong the network lifetime. References | Related Articles | Metrics

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QoS multicast routing scheme in satellite-based internet Yi, Xiu-Shuang (1); Wang, Qi (2); Huang, Min (2); Wang, Xing-Wei (2) 2008, 29 (6):  819-821+833.  DOI: - Abstract ( 236 )   HTML   PDF (1065KB) ( 552 )   Considering the predictability of topology dynamics of satellite-based Internet and QoS (quality of service) requirement of group applications, a QoS multicast routing scheme is presented. The corresponding model and its mathematical description of the QoS multicast routing problem in satellite-based Internet are given with the Lagrange relaxation introduced in to set the fitness function so as to seek a QoS multicast tree with the maximum life cycle by the PRIM algorithm, based on the sub-gradient optimization. The proposed scheme is implemented by simulation on the basis of NS2 with its performance evaluated. Simulation results showed that the proposed scheme is both feasible and effective with prolonged life cycle of QoS multicast routing tree and improved performance in comparison with the conventional one. References | Related Articles | Metrics

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Improved genetic programming algorithm used for signal detection and modeling Zhang, Zhen-Chuan (1); Wu, Jing-Jing (1); Li, Zhe (1) 2008, 29 (6):  822-825.  DOI: - Abstract ( 247 )   HTML   PDF (285KB) ( 585 )   Developing a data processing model and relevant algorithm is very important in the process of signal detection, especially when the detected signal has been distorted severely and nonlinearly by strong noise, and it is difficult to find the relational expression of the data. Describes how to use the genetic programming (GP) to solve this problem, and several improvements are given to the algorithm for practical application as follows. The Chebyshev uniformity approximation is used to evaluate the fitness of the individuals. The simulated annealing is applied to the GP to optimize the parameters of relational expression. And a piecewise function-fitting method is applied to reduce the complexity of relational expression with a group evolution strategy proposed to implement this method. References | Related Articles | Metrics

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Novel concurrent selective mapping algorithm based on property of STBC MIMO-OFDM systems Gao, Jing (1); Wang, Jin-Kuan (1); Xie, Zhi-Bin (1) 2008, 29 (6):  826-829.  DOI: - Abstract ( 246 )   HTML   PDF (875KB) ( 629 )   The orthogonal frequency division multiplexing (OFDM) has been regarded as the core technology of 4 G wireless communications system in the future, but the problem of high peak-to-average power ratio (PAPR) is the main obstacle to limit the applications of OFDM. A novel concurrent selective mapping (SLM) algorithm is thus proposed to reduce the PAPR in space-time block coded (STBC) MIMO-OFDM systems. It is proved that the conjugate symbols of two antennas have the same PAPR property, which results in that PAPR reduction to be done is only for the first symbol period. By using the property in the proposed algorithm, the cost due to computational complexity is significantly reduced with the same PAPR performance kept in comparison with the conventional concurrent SLM algorithm. Simulation results demonstrated that the performance of the proposed algorithm outperforms the conventional concurrent SLM algorithm. References | Related Articles | Metrics

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Comparative analysis of some typical roll shapes with roll gap variable through roll shifting Guo, Zhong-Feng (1); Xu, Jian-Zhong (1); Li, Chang-Sheng (1); Liu, Xiang-Hua (1) 2008, 29 (6):  830-833.  DOI: - Abstract ( 228 )   HTML   PDF (385KB) ( 795 )   Some typical roll shapes available to vary roll gap through roll shifting in rolling process were analyzed comparatively, such as basic CVC roll, optimal CVC roll and SMART Crown roll in view of the shape design, axial load acting on the roll and no-load roll gap. The results showed that when using the optimal CVC roll shape, the axial force is smaller if the strip width is in the range from 800 to 1600 mm. On the SMART Crown rolls, the no-load roll gap in both flank zones is bigger than CVC roll, which is sensitive to shape wave, so, the SMART Crown roll has superiority in controlling strip shape wave. References | Related Articles | Metrics

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Research on roll elastic deformation on a 4-h mill Zhao, Xu-Liang (1); Wang, Shu-Jun (2); Xu, Jian-Zhong (1); Zhang, Dian-Hua (1) 2008, 29 (6):  834-837.  DOI: - Abstract ( 286 )   HTML   PDF (544KB) ( 1171 )   Theory and basic formula of roll elastic deformation on a 4-h mill were investigated with the influence function analysis introduced and the analysis of roll elastic deformation program made for the simulation of an 1700 mm hot strip mill (HSM) to calculate the roll deformation. The results showed that the increase in roll bending force will decrease the crown of strip at exit, and the change in roll bending force has great influence on the distribution of pressure acted on strip by backup roll and work rolls, work roll deflection and flattening effect due to backup and work rolls, while the influence on backup roll deflection and flattening effect due to strip and work roll is small. There is a peak value of pressure due to both rolls at both ends of the backup roll. All the results mentioned above are in agreement with the theory of rolling process and what happened in the site. References | Related Articles | Metrics

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Development of control system of coolant passage for hot plates Wang, Bing-Xing (1); Zhou, Na (1); Zhang, Dian-Hua (1); Wang, Jun (1) 2008, 29 (6):  838-841.  DOI: - Abstract ( 228 )   HTML   PDF (496KB) ( 783 )   Based on the theory of material's solidifying transformation and CCT (continuous cooling transformation) curves of steel sections, an idea of coolant passage control was introduced into the plate cooling process with an exemplification given. A flexible coolant passage control system was then designed and developed by way of key units set dynamically, flexible cooling strategy and cooling water flow rate controlled to affect grain size. The control system was used to simulate the coolant passages in the industrial tests for the 400 MPa super steel plates, and the results were analyzed for the inherent causes of different microstructures/properties of the plates. Thus, a powerful technology as the ways and means was provided for the optimization of cooling process especially the development of new steel grades. References | Related Articles | Metrics

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Water flow control technique for cooling system in medium plate rolling process Sun, Tao (1); Zhou, Na (1); Wang, Bing-Xing (1); Liu, Xiang-Hua (1) 2008, 29 (6):  842-844.  DOI: - Abstract ( 278 )   HTML   PDF (284KB) ( 757 )   With the measured values of openings of all solenoid regulating values and relevant conduit flows sampled, calculated and analyzed, a curve of setting values of water flowrate in relation to the opening value is given. Then, based on the curve, the primary water output from flow controller is worked out and a closed-loop control is provided by PID controller to modify the deviation of flowmeter feedback from the setting value of water flowrate. Thus, the control accuracy of cooling water flowrate can be improved. The results show that such a flow control technique is successful in actual rolling process. References | Related Articles | Metrics

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Research on laser alloying of high-Ni-Cr infinite chilled cast iron roller Sun, Gui-Fang (1); Liu, Chang-Sheng (1); Tao, Xing-Qi (2); Chen, Sui-Yuan (1) 2008, 29 (6):  845-848.  DOI: - Abstract ( 279 )   HTML   PDF (1202KB) ( 680 )   The laser alloying technique was applied to the high-Ni-Cr infinite chilled cast iron roller coated with nano-carbide ceramics. The microstructural morphology, composition, cross-sectional microhardness distribution and the phases of the alloyed coating were analyzed by OM, SEM, microhardness tester and XRD. The results revealed that the flat alloyed coating combines metallurgically with the substrate with some cracks found in part. Under conditions that the laser power, spot diameter and overlap ratio remain unchanged, the thickness of the coating changes slightly with varying scanning speed, but the rate of cracks increases with increasing speed and the hardness of alloyed coating increases then decreases with increasing scanning speed. The optimal scanning speed is 11 m/min when the laser power is 7.2 kW, beam diameter 0.8-3 mm and overlapping rate 33.3%. At the moment, the average thickness of alloyed coating is 0.2875 mm with an average microhardness up to 1001 HV0.05, i.e. about 1.53 times as high as that of the substrate of 656 HV. References | Related Articles | Metrics

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Effect of scanning speed on microstructure and microhardness of laser cladding of silicon steel Dong, Dan-Yang (1); Zhang, Bin (1); Chen, Sui-Yuan (1); Liu, Chang-Sheng (1) 2008, 29 (6):  849-852.  DOI: - Abstract ( 439 )   HTML   PDF (1113KB) ( 960 )   High-Si coating was deposited on low-silicon steel substrate using laser to clad Fe-Si mixed powder onto that. The effects of laser scanning speed on the macro-morphology, phase composition, microstructure, chemical composition and microhardness of the laser cladding were investigated. The result showed that the cladding consists of α-Fe(Si), γ-Fe(Si) and FeSi2 phases at different scanning speeds. The microstructure of the cladding tends to grain refinement with its inhomogeneity improved with increasing scanning speed and, meanwhile, average microhardness increases due to decreasing dilution ratio in the cladding as arising from its decreasing thickness. As a result, a pore and crack-free cladding with metallurgical bonding to the substrate is formed on low-silicon steel surface by adjusting the laser scanning speed of which the optimal one is 2.5 mm/s. References | Related Articles | Metrics

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Preparation for NdFeCoBZrGa alloys anisotropic magnetic powder You, Jun-Hua (1); Lian, Fa-Zeng (1); Wang, Ji-Jie (2); Pei, Wen-Li (1) 2008, 29 (6):  853-856.  DOI: - Abstract ( 354 )   HTML   PDF (835KB) ( 578 )   HDDR (hydrogenation-disproportionation-desorption-recombination) process is an effective means by which the anisotropic Nd2Fe14B-base magnetic powder can be prepared. vacuum HDDR process, i.e. the alloy is heated to the temperature about 820°C in vacuum and then HD reactions occur under the certain hydrogen press are with the addition of the alloying element Ga affects the magnetic properties of Nd13Fe64.4-yCo16 B6.5Zr0.1Gay (y=0.1, 0.3, 0.5, 1.0) alloy was studied. The results indicated that in the vacuum HDDR process, the HD steps are the key to spur the alloy on to anisotropy, and applying the low-vacuum high-temperature schedule to the desorption step will make sure that the alloy is anisotropic. The alloying element Ga contributes to refining the grains of main phase and improving the comprehensive magnetic properties of the alloy, of which the best atom fraction is 0.5%. Treated by the vacuum HDDR process, the Nd13Fe63.9Co16 B6.5Zr0.1Ga0.5 alloy provides its best magnetic properties, i.e. iHc=1018 kA·m-1, Br=1.32 T, (BH)max=118.6 kJ·m-3 and DOA=0.787. References | Related Articles | Metrics

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Synthesis of electroconductive ceramic powder of TiN/β′-sialon by carbothermal reduction-nitridation of high titania slag Jiang, Tao (1); Li, Jiang (1); Xue, Xiang-Xin (1); Wu, Jun-Bin (1) 2008, 29 (6):  857-860+864.  DOI: - Abstract ( 639 )   HTML   PDF (476KB) ( 877 )   TiN/β′-Sialon electroconductive ceramic powder was synthesized by CRN (carbothermal reduction-nitridation) with high-titania slag, bauxite chalmette, silicon fume and carbon black as starting materials. The influences of various reaction parameters such as temperature and holding time at top temperature on the reaction process were studied by XRD, SEM and EDS, as well as the synthesis mechanism. The results showed that the synthetic reaction process of TiN/β′-Sialon powder is greatly affected by the holding time and temperature. The content of β′-Sialon in the sample becomes maximum at 1400°C for 2 hr and these process parameters are regarded as the best during synthesis. At that moment most of β′-Sialon grains in the sample exhibits long and columnar in morphology with fine TiN grains. The volatilization of SiO in the synthesis process results in great mass loss which will further increase with rising temperature and prolonged holding time for a constant temperature. References | Related Articles | Metrics

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Influence of scattering properties of sharing media on radiant thermal exchange Ma, Jin-Feng (1); Chen, Hai-Geng (1); Wu, Bin (1); Ren, Hong-Bin (2) 2008, 29 (6):  861-864.  DOI: - Abstract ( 249 )   HTML   PDF (1365KB) ( 556 )   The 1-D analytic formulae of direct radiant exchange areas and matrix expressions of total radiant exchange area are given taking account of the scattering effects of sharing media to calculate simulatively the radiant exchange areas in an 1-D system having sharing media. In comparison to the description neglecting the scattering effects of media, the numerical simulation results showed that the total radiant exchange area between gas and surface zones decreases due to the weakened scattering effect of media, while that between gas zones increases. The stronger the scattering effect of sharing media, the greater the calculation error resulting from neglecting their scattering properties. References | Related Articles | Metrics

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Research on interchangeability of fuel gases in iron and steel works Zhang, Qi (1); Cai, Jiu-Ju (1); Wu, Fu-Zhong (1); Song, Jun (1) 2008, 29 (6):  865-867+876.  DOI: - Abstract ( 261 )   HTML   PDF (1251KB) ( 575 )   Based on the heating furnace in an iron and steel works, the gas utilization efficiency was analyzed under conditions of different types of combustion through the heat balance of the furnace. The flame stability, intensity of thermal load and reasonable replacement of improper fuel gas were taken into account to investigate the fuel gas interchangeability of industrial heating furnaces and boilers. And the feasibility of the interchangeability between the gases mixing coke oven gas with blast furnace gas of different thermal values and pure coke oven gas was investigated. A conclusion was drawn that the mixed gas was available to replace coke oven gas to meet the requirements for production process, energy saving and alleviating environment pollution if the air consumption coefficient n=1.05, the ratio of coke oven gas to mixed gas α ≥ 0.3 and the thermal value of mixed gas > 7860 kJ/m3. References | Related Articles | Metrics

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Synthesis and properties of side-chain cholesteric liquid crystal polymers containing glucose Tian, Mei (1); Zhang, Bao-Yan (1); Cong, Yue-Hua (1); Wang, Wei (1) 2008, 29 (6):  868-871.  DOI: - Abstract ( 255 )   HTML   PDF (490KB) ( 616 )   The chiral monomer 1-O-(hendecene)-β-D-tetraacetyl glucopyranose (M1) and liquid crystal monomer cholesteryl 4-allyloxybenzoate (M2)were grafted onto the backbone of polymethylhydrosiloxane (PMHS). The mesomorphic properties of the series of cholesteric liquid crystalline polymers P1-P7 containing different molecular fractions of M1 from 0 to 30% were investigated by means of FTIR, 1HNMR spectra, SROT, DSC, POM, TG and X-ray. Experiment results showed that P1-P7 are thermotropic cholesteric liquid crystal polymers and that tg and ti decrease with the increasing content of M1 in the polymers and the mesomorphic temperature ranges of the polymers are broader. The thermal stability of the polymers are about 300°C with only 5wt% lost. References | Related Articles | Metrics

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MPPPM-based analysis of reliability-based sensitivity of correlation coefficients Zhang, Yi-Min (1); Wang, Shi-Peng (2); Liu, Qiao-Ling (2); Xie, Yan-Cai (2) 2008, 29 (6):  872-876.  DOI: - Abstract ( 291 )   HTML   PDF (1951KB) ( 584 )   Discusses the importance of correlation coefficients between random space variables in the reliability analysis and the reliability-based sensitivity of those correlation coefficients. Based on the MPPPM for the reliability analysis where the basic random variables are non-independent with each other and can be processed directly, the analysis of the importance and sensitivity mentioned above are carried out. Then, the effect of changing correlation coefficient on the structural reliability is obtained by the reliability-based sensitivity analysis of correlation coefficients. A numerical example is given to show how the method proposed is applied to practical project. The results illustrate the importance of correlation coefficients in reliability analysis and how it affects the structural reliability, thus providing a reference beneficial to statistics especially the reliability design. References | Related Articles | Metrics

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Analysis of definite solution to wave equation of ultrasonic machining vibration system Zhang, Nan (1); Hou, Xiao-Lin (2); Wen, Bang-Chun (1) 2008, 29 (6):  877-880.  DOI: - Abstract ( 504 )   HTML   PDF (1053KB) ( 682 )   A universal defining equation of ultrasonic vibration system is derived, with its definite solution ascertained involving both linear and nonlinear boundary conditions. Then, based on the wave theory, universal defining equation of composite radius-changing horn is given in exponential form, and the linear boundary condition is set to solve the sectionalized nonlinear equation to derive the general expressions of wave node position and amplification coefficient relevant to the horn. Furthermore, the nonlinear boundary condition is set to provide the definite solution to the nonlinear dynamic model of the system. The numerical results reveal that the definite solution gives a correct expression to the dynamic characteristic of ultrasonic vibration system and wave motion of the horn, thus providing theoretically a reference for other ultrasonic vibration system. References | Related Articles | Metrics

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Simulation of rf-biased plasma sheath using hydrodynamic method Lu, Shao-Bo (1); Lin, Zeng (1); Ba, De-Chun (1); Lee, In-Seop (2) 2008, 29 (6):  881-884.  DOI: - Abstract ( 293 )   HTML   PDF (1021KB) ( 1116 )   A self-consistent fluid model was developed describing the spatiotemporal characteristics of parameters in the radio-frequency plasma sheath under DC bias without molecule collision, considering the effect of DC negative bias of electrode on ion motion. In the model, the thickness of the sheath was regarded as a function of time, and the relationship between the instantaneous sheath thickness and potential drop of sheath was established by an equivalent circuit model. Simulation results showed that the electrode presents a cyclically non-sinusoidal potential. The variation cycles of both sheath thickness and potential of electrode are the same in opposite trends, and they lag slightly behind radio-frequency cycle. References | Related Articles | Metrics

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Optical properties of TiO2 thin films deposited by PEM controlled reactive sputtering Duan, Yong-Li (1); Ba, De-Chun (1); Xu, Sheng (2); Fan, Chui-Zhen (2) 2008, 29 (6):  885-888.  DOI: - Abstract ( 291 )   HTML   PDF (1107KB) ( 626 )   Titanium dioxide thin films for optical applications were deposited on glass substrates by reactive mid-frequency (MF) magnetron sputtering with two Ti metal targets. To obtain a high deposition rate, the plasma emission monitor (PEM) was used to control the sputtering process. The structure and dynamic deposition rate of the films deposited with various deposition parameters were investigated by surface profiler, XRD and AFM, and the optical properties were measured and calculated by spectrophotometer and thin-film analyzer. The results showed that higher PEM setpoints can enable the films to have higher reflective index. In short, the TiO2 thin films prepared in this way can provide favorable optical properties. References | Related Articles | Metrics

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On the resolution of workspace problem of a parallel machine tool Zhu, Chun-Xia (1); Zhu, Li-Da (1); Yang, Bin-Jiu (1); Liu, Yong-Xian (1) 2008, 29 (6):  889-892.  DOI: - Abstract ( 246 )   HTML   PDF (267KB) ( 824 )   Taking the 3-TPT parallel machine tool developed by this university as example, the two different methods resolving the workspace problem of parallel machine tool are discussed. One is to solve the kinematical inverse equation of parallel machine tool, then the available workspace is found out by analytical method. The other one is using the virtual prototype technique instead of the analytical method as above to resolve the workspace problem. It is such a method that is simple and clear in thought process as a shortcut and available to use in wide range, i.e. only a model of virtual prototype of parallel machine tool is needed to develop with some constraint conditions given, the workspace can be found out directly without complex derivation process. The two methods mentioned above are compared with each other, and the results indicate that the method by virtual prototype technique is more visual and practical and simpler. References | Related Articles | Metrics

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Failure mechanism study on vertically stratified rock mass around deep tunnel Jia, Peng (1); Tang, Chun-An (2); Zhang, Guo-Lian (1) 2008, 29 (6):  893-896.  DOI: - Abstract ( 235 )   HTML   PDF (1185KB) ( 762 )   Using the RFPA numerical code, the failure process of vertically stratified rock mass around underground excavations is simulated and the failure characteristics between vertically stratified and intact rock mass are comparatively discussed under different lateral pressure coefficients. The results show that the lateral pressure coefficient has a significant influence on the failure mode of vertically stratified rock mass. Only if the lateral pressure coefficient is smaller than 1, would the side walls take the buckling failure mode; or else, the failure zones mainly concentrate at the crown and floor of tunnel. It is also found that the beam-slab theory in application to the structural mechanics does not entirely suit the stability evaluation of vertically stratified rock mass. Furthermore, it is found that for deep excavations the failure mode of rock mass is controlled mainly by the stress instead of structural planes. It is the stress that mainly controls the failure mode of rock mass, other than the structural plane in the rock mass. References | Related Articles | Metrics

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Ecological footprint of China's iron and steel industry Yu, Hong-Min (1); Wang, Qing (1); Yu, Xue-Fei (2); Liu, Jian-Xing (1) 2008, 29 (6):  897-900.  DOI: - Abstract ( 311 )   HTML   PDF (987KB) ( 567 )   China's iron and steel industry is facing high energy/water consumption with highly increasing waste and heavy pollution. It has become one of the industries that form the most serious environmental pollution. The ecological footprint as research method is thus introduced into the problem to discuss the way of how to save resources and improve environmental efficiency. The results show that the ecological footprint per 10?000?t steel tends to decrease now, but the ecological footprint increases greatly at high speed because of the rapid growth of steel production. The key part of the ecological footprint in steel industry is the indirectly occupied land area by the energy consumed (amounted to over 99% of the whole iron and steel industry). So the key to reduce the ecological footprint of iron and steel industry is to further reduce the energy consumption so as to reduce pollution. However, in recent years the water footprint was on fast decline in steel industry, reduced sewage emissions, and achieved certain results. References | Related Articles | Metrics

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Pulsate dust-purging mechanism of plenum-type bag filter Xu, Xin-Yang (1); Wu, Yan (1); Zhao, Guang-Ling (1); Ding, Shu (1) 2008, 29 (6):  901-904.  DOI: - Abstract ( 270 )   HTML   PDF (241KB) ( 1273 )   To reveal the pulsate dust-purging mechanism of plenum-type bag filter, the adiabatic energy equation based on aerodynamics is applied to the venting system, so as to drive theoretically the reverse air speed expression of bag filter surface in pulsate dust-purging process. Then, the removing force due to reverse airflow, which is acting on the dust layer on bag filter surface, can be obtained. And the relationship between the removing force and dust removing rate is given to the data resulting from the test of bag filter model. In this way the reverse air speed and air flow rate for purging are available to obtain, which are both necessary to the preset removing rate under conditions that the dust burden of bag filter is constant. The investigation results provide a reference necessary to the design of dust-purging system. References | Related Articles | Metrics

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Leadership skills of top executives to implement developmental strategies: with 15 commercial enterprises in qinhuangdao city as examples Ren, Rong-Rong (1); Yang, Xi-Huai (1) 2008, 29 (6):  905-908.  DOI: - Abstract ( 189 )   HTML   PDF (299KB) ( 448 )   Explores empirically the formative factors of Chinese top executives' leadership skills at implementing the developmental strategies of their commercial enterprises. Based on earlier works the formative factors are comprehensively considered and summed up. Then EFA (exploratory factor analyses) and CFA (confirmatory factor analysis) are made by way of 72 questionnaires, which have all been completed and returned to develop a 5-dimensional model to reveal the top executives' leadership skills at implementing their developmental strategies. Fitting the model by introducing SEM (structural equation modeling) the formative factors are verified including the five strategical aspects as follows: executing, decision-making, analyzing and motivating in addition to their individual mature consideration. References | Related Articles | Metrics

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Empirical study on FDI's technology spillover effect on equipment manufacturing industry in Shenyang Zhang, Lan-Xia (1); Wang, Jing (2); Yang, Hai-Jun (1) 2008, 29 (6):  909-912.  DOI: - Abstract ( 220 )   HTML   PDF (179KB) ( 535 )   According to the Cobb-Douglas' production function, a quantity model was developed including a basic model and extension one with some assumptions given. To verify the assumptions, the technology spillover effect of foreign direct investment (FDI) on the equipment manufacturing industry in Shenyang was studied empirically with the relevant data from 1999 to 2003 taken as reference. The results showed that FDI has contributed greatly the technology spillover effect to the equipment manufacturing industry in Shenyang. All the three factors selected have obviously positive influence, i.e. the market competition, labor mobility, and the opening degree of industry. Such a conclusion is important and beneficial to taking advantage efficiently of FDI and improving its technology spillover effect. References | Related Articles | Metrics