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15 September 2012, Volume 33 Issue 9 Previous Issue    Next Issue
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Finite-time robust dissipative control for a class of descriptor systems Su, Zhan (1); Zhang, Qing-Ling (1); Ai, Jun (1) 2012, 33 (9):  1217-1221.  DOI: - Abstract ( 692 )   HTML   PDF (2526KB) ( 721 )   With parameters uncertainty and external disturbance considered, the sufficient condition of the finite-time robust stability under twin-fuzzy rules for a class of descriptor systems was described using linear matrix inequalities (LMIs). Based on the parallel distribution compensation(PDC), a robust dissipative controller under twin-fuzzy rules was designed to guarantee dissipative performance of uncertain and disturbed fuzzy descriptor systems in a finite-time interval. The control system was effectively confined within the desired state-space ellipsoid. A numerical example applied to inverted pendulum model was given to demonstrate the efficiency of the proposed approach. References | Related Articles | Metrics

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Localization method of far field multiple sound sources based on two L-type array Kim, Guang-Myong (1); Xie, Zhi (1); Zhang, Chuan-Yi (1); Kim, Yil-Byong (2) 2012, 33 (9):  1222-1225+1239.  DOI: - Abstract ( 627 )   HTML   PDF (1903KB) ( 719 )   In order to solve the problem that the traditional methods can not accurately measure the localization of multiple sound sources in far field, a new multiple sound sources localization method was presented that could be used in both the near field and the far field. This method adopted two L-shape microphone array, and in each array the signal's DOA was obtained by jointly estimating the DOA and frequencies of the signals. Finally, localization of multiple sound sources could be estimated based on the DOA's pair of two L-type microphone array. Simulation results indicated that the localization of multiple sound sources could be accurately measured in both the near field and the far field. By adjusting the distance between the two L-type microphone array, a standard deviation below 5% of the sound localization accuracy could be obtained based on the proposed method. References | Related Articles | Metrics

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Detection of the weak signal with unknown frequency based on the coupled chaos oscillator Yang, Dong-Sheng (1); Li, Le (1); Yang, Jun (1); Wang, Gang (1) 2012, 33 (9):  1226-1230.  DOI: - Abstract ( 683 )   HTML   PDF (2819KB) ( 742 )   A sub-frequency measurement method for weak signals with unknown frequency was presented. Due to the sensitivity of the state transitions of the phase trajectories of the coupled Duffing system to the weak signal input, the detection for a weak signal submerged in strong noises was implemented to solve the difficult problems of weak signal detection. Based on the proposed method, the problem on misjudgment of weak signal detection method based on single Duffing oscillator under the influence of noise effectively was solved. And the limitation had been broken that the existing detection methods of weak signal based on chaotic oscillator could only detect the weak signal with known frequency. Simulation results showed that the method could indeed detect the frequency of weak periodic input signal more accurately, resulting in the improvement of the weak signal detection techniques. References | Related Articles | Metrics

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Study of comprehensive trust model in online auction Wang, Wen-Jia (1); Wang, Ding-Wei (1) 2012, 33 (9):  1231-1234.  DOI: - Abstract ( 497 )   HTML   PDF (1160KB) ( 647 )   A comprehensive trust model was presented mainly for the problems existed in the current assessment of trust degree in online auction. It was a fact that different participants in online auction had different viewpoints on the trust computation, such as recent credibility, time weight, value of the transaction, etc. The assessments of trust degree with multi-viewpoints of different participants being evaluated, credibility of participants was calculated separately. The comprehensive trust model was able to greatly improve the accuracy of calculation. Thus, it is more effective for analyzing the trust degree of the different participants in online auction. References | Related Articles | Metrics

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Hybrid optimization algorithm for solving combining tundish MTSP model on continuous casting plan Yi, Jian (1); Tan, Shu-Bin (1); Li, Wei-Gang (1); Du, Bin (1) 2012, 33 (9):  1235-1239.  DOI: - Abstract ( 688 )   HTML   PDF (192KB) ( 1210 )   The combining tundish problem on continuous casting plan was described and the multiple traveling salesman problem (MTSP) model was constructed. A hybrid optimization algorithm composed of the heuristic method, the k-opt neighborhood search, and the estimation of distribution algorithms (EDA) was proposed to solve the model. First, a heuristic method was used to determine the counts of dummy furnace which were involved in chromosome code to fix on the code length. Each chromosome presented a scheme of combining tundish and then the probability matrix model of the EDA was designed to optimize chromosome globally. Moreover, the k-opt was used as local search strategy. Unlike genetic algorithm(GA), the EDA had no crossover operator, therefore the illegal code resulted from crossover operator was avoided. Simulation results on the real production data indicated that the proposed algorithm had fairly good performance and utility. References | Related Articles | Metrics

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Logistics routing optimization based on improved ant colony algorithm Xu, Jiu-Qiang (1); Xing, Pei-Long (1); Kong, Qiu-Shi (1); Liu, Da-Peng (1) 2012, 33 (9):  1240-1243+1252.  DOI: - Abstract ( 636 )   HTML   PDF (1343KB) ( 698 )   Due to computation complexity, lower accuracy and premature convergence of the conventional algorithm, the ant colony algorithm was improved to solve the routing problem of logistics. In order to eliminate the problems that ant colony algorithm is easy to be stagnant and its convergence is slow, the algorithm was improved including the following points such as the transfer strategies of the ants, the pheromone update method and the integration of genetic algorithm. To solve the path optimization of simultaneous delivery and pickup, the heuristic function was added and the transfer strategies were designed, which made the algorithm conduct a search by considering a combination of factors reasonably, and could find the next right point more comprehensively and more accurately, then, a better path could be gotten. References | Related Articles | Metrics

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Network convergence policy based on the non-cooperative gaming Wang, Xing-Wei (1); Li, Zhan-Guo (1); Liu, Xiang-Dong (1) 2012, 33 (9):  1244-1247+1265.  DOI: - Abstract ( 563 )   HTML   PDF (2447KB) ( 642 )   The service and relationship of network operators in China being described, a service and benefit model was presented, and then the non-cooperative gaming between the competitive network operators was analyzed. Analysis results showed that the effect of combined operation of competitive network operators under non-cooperative gaming conditions could be attained by regulating cooperation factors between them, with the Nash equilibrium and the global system optimum converged. It could be concluded that the physical merging of the networks owned by different operators was not necessary. With the participation of network convergence center, the efficient network convergence could be attained by appropriate charging policy supervision and adjusting the operators charging relationship. References | Related Articles | Metrics

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Research on centralized measurement method of internet AS-level topology Zhao, Hai (1); Jia, Si-Yuan (1); Ai, Jun (1); Cui, Xing-Bing (1) 2012, 33 (9):  1248-1252.  DOI: - Abstract ( 606 )   HTML   PDF (1789KB) ( 817 )   To solve the problem that how to find important nodes accurately and quickly in complex and huge AS-level networks, a valuable research of centralization was carried out. With three common measurement such as degree centrality, closeness centrality, betweenness centrality, core centrality was proposed to act as an indicator to measure high-core nodes combination. The importance of a node within a network was characterized as the extent of which the network has been destroyed by deleting the node. The applicability of the closeness centrality was not good as degree centrality and betweenness centrality for Internet AS-level. There was high similarity in degree centrality and betweenness centrality when the proportion of attack nodes was smaller than 0.5%. Core centrality was applied to finding out the communities which were made up of high-degree and closely-connected nodes within networks. References | Related Articles | Metrics

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A wormhole attack detection algorithm in wireless sensor networks Dong, Xiao-Mei (1); Yang, Jie (1) 2012, 33 (9):  1253-1256.  DOI: - Abstract ( 757 )   HTML   PDF (1505KB) ( 823 )   Features of wormhole attacks in wireless sensor networks were analyzed. According to the features that some routes may be shortened and the number of neighbors of some nodes may be increased, a detection algorithm was proposed to detect wormhole attacks in wireless sensor networks. Some source and destination (SD) node pairs were firstly deployed at the edge zone. Then the route discovery process was launched to find dubious route with abnormally fewer hops. After that, each node on the dubious paths was detected by checking the number of its neighbors. If such a node had more neighbors, it could be made sure that the node was infected and there was a wormhole attack in the network. The infected nodes would be isolated from the network to avoid more damages. Experimental results showed that the proposed algorithm has low false positive and high accuracy. References | Related Articles | Metrics

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Topology control algorithm based on directional antenna in wireless Ad Hoc networks Liu, Jun (1); Sun, Qian (1); Li, Shao-Hua (2); Zheng, Zhong (2) 2012, 33 (9):  1257-1260.  DOI: - Abstract ( 612 )   HTML   PDF (1173KB) ( 900 )   In order to use directional antenna to solve the problems including heterogeneous nodes, limited resource and narrow bandwidth in wireless Ad Hoc network, a topology control algorithm named K-DRNG was proposed on the basis of directional antenna in heterogeneous wireless Ad Hoc network. The algorithm was mainly composed of three phases. The first stage was called information collection, in which each node collected the information of neighborhood by adjusting transmitting power and controlling sector conversion. The second stage was called topology construction, in which each node constructed directed relative neighborhood graph based on link weights and residual energy. The third stage was called topology optimization, in which each node constructed subgragh of initial topology and added or deleted additionally directional links with neighborhood to guarantee bidirectional connectivity of topology. Simulation results showed that the proposed algorithm can reduce the average energy consumption of nodes, increase the spatial reuse of radio resource, and thus improve integral network performance. References | Related Articles | Metrics

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Recrystallization texture development in asymmetrically rolled non-oriented silicon steel Pei, Wei (1); Sha, Yu-Hui (1); Zhao, Rui-Qing (2); Zuo, Liang (1) 2012, 33 (9):  1261-1265.  DOI: - Abstract ( 713 )   HTML   PDF (3773KB) ( 741 )   The non-oriented silicon steel sheets were produced by asymmetric cold rolling with three speed ratios of 1.06, 1.125 and 1.19, respectively, and produced also by conventional symmetric cold rolling for comparison. It was found that the asymmetric rolling weakens {001}~{112}<110> components in α fiber (<110>//RD), while strengthens {111}<112> and weakens {111}<110> in γ fiber (<111>//ND). EBSD results showed that η(<001>//RD) and η′ (Ψ=75°, θ=0~45°, φ=0°) grains nucleate within shear bands in {111}<112> and {111}~{225}<110> deformed grains, respectively. η′ becomes the main recrystallization component because of nuclei size advantage. Recrystallization texture and magnetic properties can be improved by the change of cold rolling texture induced by asymmetric rolling, and the effect of asymmetric rolling is more obvious with the increasing of speed ratio. References | Related Articles | Metrics

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Microstructure evolution and precipitation behavior of Nb-Ti microalloyed steel under different processing Xu, Yang (1); Yi, Hai-Long (1); Sun, Ming-Xue (1); Liu, Zhen-Yu (1) 2012, 33 (9):  1266-1269.  DOI: - Abstract ( 504 )   HTML   PDF (2329KB) ( 862 )   The effects of different finish cooling temperature and holding time on microstructure, precipitation behavior of Nb-Ti microalloyed steel were investigated by using Gleeble 3800 thermal mechanical simulator, transmission electron microscope(TEM) and nanoindentation instruments. The results showed that with the increase of the finish cooling temperature, the size of ferrite and the fraction of pearlite increase, and the fraction of bainite reduces, the Vickers microhardness increases first then decreases and reaches the maximum when the finish cooling temperature is 640°C. Rows of interphase precipitate and randomly dispersed precipitates can be found in ferrite matrix when the holding time is 0?s, and when the holding time is 100 s, the main precipitation is randomly dispersed precipitates. With the increase of the holding time, the nanoindentation is reduced 140 MPa. References | Related Articles | Metrics

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Microstructure and properties of U75V 60 kg/m heavy rail after slack cooling Kang, Hao (1); Zhao, Xian-Ming (1); Xia, Wen-Zhen (1); Wu, Di (1) 2012, 33 (9):  1270-1273+1298.  DOI: - Abstract ( 703 )   HTML   PDF (1885KB) ( 681 )   The samples of U75V 60 kg/m heavy rail were heated to 900°C, simulating the temperature of heavy rail at the outlet of universal rolling, then the samples were cooled in open air for 25 s, simulating the temperature drop of heavy rail from the outlet to cooling bed; at last, the samples were put into air spraying channel to cool slackly on the top and both sides of rail head. The optimal cooling parameters were obtained after a lot of experiments: the distance between spraying nozzles and surface of rail head is 15 mm, the air pressure is 0.26 MPa, the spraying time is 80 s, and the air temperature is 28°C. Under this cooling condition, the hardened layer shows as "cap-shaped", the thickness of hardened layer at the center of rail head is more than 24 mm; the microstructure is fine pearlite, the average pearlite interlamellar spacing reduces about 50 nm than that before slack cooling; the tensile strength is more than 1300 MPa at the top fillets and the percentage elongation is more than 13%, increasing more than 20% and 60% than that before slack cooling, respectively. References | Related Articles | Metrics

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Thermodynamic analysis of γ and γ′ phases in new-type co-based superalloy Yang, Shu-Yu (1); Jiang, Min (1); Wang, Lei (1) 2012, 33 (9):  1274-1277.  DOI: - Abstract ( 1100 )   HTML   PDF (2472KB) ( 964 )   The precipitation behaviors of γ′ phases and distribution coefficients of Ni, Al and W between γ and γ′ phases in the Co-Ni-Al-W-Cr alloy were studied by thermodynamic analysis method. The effect of distribution coefficient of Ni between γ and γ′ phases on the alloy strengthening was also discussed. The results show that the stability of the γ′ phase can be enhanced by the addition of Ni. The homogeneity range of the γ′ phase can be enlarged with the increasing of Ni content, which shows that Ni can improve the working temperature of the Co-Al-W-based superalloys. In Co-Al-W-Ni-Cr alloys, the x(Al)/x(W) ratio has an effect on the distribution coefficient KNiγ′/γ of Ni between γ and γ′ phases. KNiγ′/γ has a maximum value of 1.24 when x(Al)/x(W) ratio is 2.60. The results can be used for the developing new-type Co-based superalloy. References | Related Articles | Metrics

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Effect of hydrolysis time of silane on corrosion resistance of vinyltriethoxysilane films on Q235 steel surfaces Zhang, Xu-Ming (1); Wang, Jian-Jun (1); Liu, Chun-Ming (1); Yin, Yue-Jun (2) 2012, 33 (9):  1278-1281.  DOI: - Abstract ( 676 )   HTML   PDF (1597KB) ( 842 )   The vinyltriethoxysilane films on the surfaces of Q235 steel were prepared by hydrolysis of silane solution. The corrosion resistance of hydrolyzing vinyltriethoxysilane films prepared for different immersion time in the aqueous solution of 3.5%NaCl was investigated by the electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization. The results showed that the vinyltriethoxysilane films prepared with the silane solution hydrolyzed for 8 days on the surfaces of Q235 steel has the optimal corrosion resistance because the anode and cathode reactions are restrained during the corrosion. The corrosion current density of the Q235 steel coated with the vinyltriethoxysilane films is decreased by almost three orders of magnitude and the polarization resistance Rp is increased by about two orders of magnitude as well as its low-frequency impedance is increased by more than three orders of magnitude compared with those of the blank Q235 steel sheets without hydrolyzing vinyltriethoxysilane film. References | Related Articles | Metrics

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Measured temperature processing technology for plate controlled cooling system Wang, Bing-Xing (1); Yuan, Da (1); Li, Yong (1); Wang, Zhao-Dong (1) 2012, 33 (9):  1282-1285.  DOI: - Abstract ( 565 )   HTML   PDF (2070KB) ( 681 )   Taking the measured temperature processing technology for the plate controlled cooling system as the research object, a measured temperature filtering method with fault tolerance was established and the effect of measuring error and tracking error was eliminated. On the basis of least square method, the curve for the measured temperature was fitted as the criterion for the plate length cooling uniformity and this method was used in cooling schedule setting and self-learned calculation model. The plate longitudinal sample controlled method based on the measured temperature was established. The temperature of every longitudinal sample was acquired by linear interpolation method to realize the high precision control of finish cooling temperature and cooling rate by the controlled cooling system. References | Related Articles | Metrics

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Flow auto-calibrating technology of ultra fast cooling system in plate mill Hu, Xiao (1); Li, Zhen-Lei (1); Wang, Zhao-Dong (1); Wang, Guo-Dong (1) 2012, 33 (9):  1286-1289.  DOI: - Abstract ( 739 )   HTML   PDF (1772KB) ( 640 )   Flow-opening degree calibrating curve is usually used for accelerating the control speed of flow in the ultra fast cooling system of plate mill. The precision of calibrating curve influences directly the accuracy of flow control. Taking the new ultra fast cooling equipment applied in many plate mill plants of iron and steel group corp as an example, the electric valve regulating characteristics was analyzed, and the effective auto-calibrating method of flow-opening degree calibrating curve was developed. The results showed that this method of obtaining flow-opening degree calibrating curve by using flow auto-calibrating technology not only is convenient for maintenance but also achives the better speed and accuracy of flow control. It could be used to improve the design of ultra fast cooling equipment and control system. References | Related Articles | Metrics

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Effect of BN addition on mechanical properties and microstructure of TiB2-Al composites Wang, Chao (1); Xue, Xiang-Xin (1); Cao, Xiao-Zhou (1); Yang, He (1) 2012, 33 (9):  1290-1293.  DOI: - Abstract ( 593 )   HTML   PDF (1288KB) ( 700 )   The phase composition, microstructure and mechanical properties of TiB2-Al composites prepared by vacuum metal infiltration were examined and the effect of BN addition on the microstructure and mechanical properties of TiB2-Al composite was studied. The results showed that AlN is formed due to the surface reaction between Al and BN. AlN exists between TiB2 and Al. With the increase of BN addition, the flexural strength gradually decreases, the fracture toughness firstly increases and then decreases, and the hardness gradually increases. Al amount immersed into the preform is the main reason affecting fracture toughness. TiB2-Al composite with addition of 10% BN shows the better mechanical properties, the flexural strength is 538.48 MPa, the fracture toughness is 7.14 MPa·m1/2 and the hardness(HRC) is 21.2, respectively. References | Related Articles | Metrics

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Formation mechanism of Al2O3-TiN compound inclusion during IF steel solidification process Li, Zhi-Qiang (1); Yuan, Lei (1); Liu, Tao (1); Yu, Jing-Kun (1) 2012, 33 (9):  1294-1298.  DOI: - Abstract ( 545 )   HTML   PDF (2144KB) ( 920 )   The mechanism of precipitation and growth of Al2O3-TiN compound inclusions during IF steel solidification process was researched by experiments and theoretical analysis. The results showed that when the solid fraction exceeds 0.9, Al2O3 and TiN precipitate successively by heterogeneous nucleation and Al2O3-TiN compound inclusions are formed. The final diameter of compound inclusions increases with the decrease of cooling rate. When the cooling rate is constant, the growing extent of compound inclusions decreases with the increase of the radius of inclusions used for nucleus. The growing extent of TiN inclusions formed outside the Al2O3-TiN compound inclusions increases with the decrease of the radius of Al2O3 inclusions inside. References | Related Articles | Metrics

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Numerical simulation of heat exchange in vertical tank of waste heat recovery Dong, Hui (1); Li, Lei (1); Cai, Jiu-Ju (1); Li, Jie (2) 2012, 33 (9):  1299-1302.  DOI: - Abstract ( 517 )   HTML   PDF (1514KB) ( 749 )   Gas-solid heat transfer process in sinter bed layer is one key factor deciding whether waste heat recovery with vertical tank is feasible. Using Comsol Multiphysics software, the heat exchange in vertical tank was calculated on the basis of the steady heat transfer condition. The results showed that the ratio of gas to sinter and the depth of bed layer are the main factors affecting the heat exchange in vertical tank. The outlet temperature of the sinter and cooling gas is reduced gradually with increase of the ratio of gas to sinter. The value of exergy carried by the cooling gas increases firstly and then decreases with increase of the ratio of gas to sinter. The outlet temperature of cooling gas increases gradually and the ratio of gas to sinter increases with the increase of depth of bed layer. The value of exergy carried by the cooling gas increases firstly and then decreases with increase of depth of bed layer. When matching a single vertical tank for a 360 m2 sintering machine, the appropriate height is 6~7 m and the ratio of gas to sinter should be in the range of 1500~1650 m3/t. When matching two vertical tank for the 360 m2 sintering machine, the appropriate height is 5~6 m and the ratio of gas to sinter should be in the range of 1360~1550 m3/t. References | Related Articles | Metrics

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Numerical simulation of gas-liquid flow behavior in a copper matte bottom-blowing converter Shao, Pin (1); Zhang, Ting-An (1); Liu, Yan (1); Wang, Dong-Xing (1) 2012, 33 (9):  1303-1306+1318.  DOI: - Abstract ( 597 )   HTML   PDF (2007KB) ( 864 )   The gas-liquid two-phase flow behavior in the copper matte bottom-blowing converter was described with the Euler-Euler model, and the simulation results are consistent with the measured results. On this basis, the gas-liquid two-phase flow behavior and the gas volume at different jet angles with double nozzles were described. The results showed that the splash decreases with the increasing of jet angles with double nozzles. When the jet angle is 14 degrees, the splash is the most serious. The transverse penetration distance of gas-liquid jet trajectory and the distribution area of turbulent kinetic energy increase with the increasing of jet angles, and the residence time of the gas phase in the pool increases. However, after the jet angle exceeds a certain range, the vertical distance from the jet nozzle to the liquid surface decreases when the jet angle continues to increase. Then the residence time of gas phase in the pool is shortened. When the jet angle is 28 degrees, the gas volume fraction is the highest and distribution of the turbulent kinetic energy is the largest. References | Related Articles | Metrics

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Investigation of anode and electrode processes of solid state in situ electrochemical reduction from TiO2 to Ti Guan, Chang-Long (1); Zhang, Ting-An (1); Dou, Zhi-He (1) 2012, 33 (9):  1307-1310.  DOI: - Abstract ( 517 )   HTML   PDF (1216KB) ( 704 )   The anode process of solid state in situ electrochemical reduction from TiO2 to Ti was studied by cyclic voltammetry and the whole electrode process was analyzed. The results show that the anode process is a one-step reversible oxidizing reaction of two-charge with the products undissolved and CO2 is produced at carbon anode. The anode reactions can be expressed as C+2O2--4e=CO2. The general electrode reactions can be expressed as 2TiO2+C=2TiO+CO2, 2TiO+C=2Ti+CO2, 2CaO+C=2Ca+CO2. The Ca produced at cathode can also continue the thermo-reduction reactions. The reduction of TiO2 to Ti is attributed to the directly electrochemical reduction of TiO2 and calciothermic reaction when there is a few amount of Ca in the CaCl2 melt. References | Related Articles | Metrics

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Determination of the vanadyl sulfate ion-pair dissociation constant at 298.15 K using electric conductivity Zhang, Shu-Di (1); Zhai, Yu-Chun (1); Yan, Chuan-Wei (2) 2012, 33 (9):  1311-1314.  DOI: - Abstract ( 668 )   HTML   PDF (1309KB) ( 1088 )   To optimize electrolyte ratio of the vanadium redox flow battery and set a reasonable charge and discharge system, the free vanadium ion activity, ion-pair dissociation constant and other thermodynamic properties should be clarified. The conductivity of the VOSO4·3.53H2O(s) in aqueous solution was determined using the electric conductivity method at 298.15 K. The limiting molar conductance was obtained using the Origin data fitting and then the activity coefficient was solved with the improved Ostwald dilution law and the Davies equation, so as to obtain the true solution ionic strength. The vanadyl sulfate ion-pair dissociation constant was calculated through the Fuoss method. The vanadyl sulfate limiting molar conductance Λ0 is 203.252 032 5 S·dm2·mol-1 and the vanadyl sulfate ion-pair dissociation constant Kd is 0.001 961 62, which may provide a basic data for the battery thermodynamic properties. References | Related Articles | Metrics

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Preparation of high purity Al(OH)3 from aluminous slag using alkali extraction and carbonation Shen, Xiao-Yi (1); Chang, Long-Jiao (1); Wang, Jia-Dong (1); Zhai, Yu-Chun (1) 2012, 33 (9):  1315-1318.  DOI: - Abstract ( 557 )   HTML   PDF (1374KB) ( 640 )   Taking aluminous slag of clay nickel ore acid soaking liquid as raw material, high purity Al(OH)3 powder was successfully prepared through alkali extraction and split-step carbonation. The influences of the alkali extraction temperature and pH value on the Al dissolution rate of aluminous slag, and the pH value of carbonation end and carbonation temperature on the Al precipitation rate were also investigated, respectively. The appropriate alkali extraction conditions were pH value of 14, temperature of 90°C and time of 10 min, and the carbonation conditions were the pH value of the carbonation end of 9 and temperature of 75°C, respectively. The Al(OH)3 powder was characterized using XRD, SEM and chemical component analysis. The results indicate that the crystal of Al(OH)3 powder grows well, and the particles of Al(OH)3 are irregular with rough surface, loose and porous structure. References | Related Articles | Metrics

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Impurity remove of carbonized rice husk for preparing high purity silicon Li, Feng (1); Xing, Peng-Fei (1); Zhao, Pei-Yu (1); Tu, Gan-Feng (1) 2012, 33 (9):  1319-1322.  DOI: - Abstract ( 592 )   HTML   PDF (1436KB) ( 780 )   This paper reported on the methods to purify the carbonized rice husk (CRH) including acid leaching and ultrasonic field purification. The effect of mass fraction of hydrochloric acid leaching time, temperature, ratio of leaching liquid to solid and strring speed on impurity remove was investigated. The optimal leaching conditions are CRH particle size less than 75 μm, 5% hydrochloric acid, reaction time of 3 h, temperature of 60°C, ratio of leaching liquid to solid at 14:1 and stirring speed of 60 r/min, respectively. Under this optimum condition, 96.41% of the metallic elements and 66.68% of the non-metallic elements can be removed. The effect of ultrasonic field was also investigated and the elimination of metallic and non-metallic impurities can reach up to 99.07% and 71.77%, respectively. References | Related Articles | Metrics

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Research on the optimal packing of rectangular parts for damaged raw materials Dong, De-Wei (1); Yan, Yun-Hui (1); Wang, Zhan (1) 2012, 33 (9):  1323-1326.  DOI: - Abstract ( 628 )   HTML   PDF (1194KB) ( 920 )   The optimal packing of rectangular parts for damaged raw material is a combinatorial optimization problem. A method based on partheno-genetic algorithm (PGA) was thus proposed. It translated the packing of rectangular parts for damaged raw materials into a special coding of PGA, and the best sequence of the rectangular parts and their optimum rotation were achieved by optimal searching using the PGA genetic operators. Finally, automatic packing was realized by packing algorithm of the lowest point of inside no fit polygon of the rectangular part on damaged raw material. Experiments indicate that the algorithm is effective and practical. References | Related Articles | Metrics

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Changing mechanism of grinding surface integrity under small cutting depth conditions Xiu, Shi-Chao (1); Bai, Bin (1); Wei, Jian-Hen (1); Liu, Ming-He (1) 2012, 33 (9):  1327-1330.  DOI: - Abstract ( 624 )   HTML   PDF (1473KB) ( 585 )   The residual stress and hardness changes of ground surface play the key role in measuring the surface integrity of workpiece, and also have significant effect on the fatigue strength and wear resistance. Concerning grinding process under small cutting depth conditions in practical engineering, based on the grinding strength test of 45 steel specimens, the microstructure, thickness, surface hardness and residual stress of the grinding affected layer were studied. This work highlights the discussions of the formation mechanism and microstructure of the grinding affected layer. The results show that the surface residual tensile stress exists on the workpiece surface after dry grinding at small cutting depth. The residual stress tends to decrease with the increase of cutting depth or workpiece speed. The grinding affected layer thickness tends to increase with the increase of depth of cut or decrease of workpiece speed under small cutting depth conditions. The results indicate that reasonable grinding parameters and grinding wheel parameters can enhance the grinding capacity in dry grinding at small cutting depth. References | Related Articles | Metrics

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Geochemical characteristics and tectonic setting for volcanic rocks of Zhangjiakou formation in the Chaoyang Area, Western Liaoning Peng, Yan-Dong (1); Huang, Fei (2); Xing, De-He (3); Lü, An-Cai (4) 2012, 33 (9):  1331-1335.  DOI: - Abstract ( 823 )   HTML   PDF (1619KB) ( 771 )   Zhangjiakou volcanic cycle in Chaoyang area may be divided into three sub-cycles. The volcanic rocks of Zhangjiakou formation mainly consist of rhyolites, trachyte and trachyandesites. The geochemical characteristics indicate that the volcanic rocks belong to the high-K calc-alkaline magmatic serious. The volcanic rocks are characterized by high SiO2, Al2O3, K2O and Na2O, and comparatively low MgO and TiO2 components. The average value of σ is 2.59. The volcanic rocks are obviously enriched in incompatible elements (K, Rb, Sr, Zr, Ba, Pb, Li), and depleted in compatible elements (Ti, Co, Ni, Cr, V). The volcanic rocks are riched in LREE. There is a slightly low Eu negative abnormality and low Ce negative abnormality. Combined to the study of regional structures and geochemistry of volcanic rocks, it is considered that the volcanic rocks are mainly originated from the crust materials and the lithogenesis take partial melting as a major part. The volcanic rocks of Zhangjiakou volcanic cycle are formed in the transitional environment of compressional orogeny and extensional structure. They have the basic characteristics of continental intra-plate volcanic rocks. References | Related Articles | Metrics

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Study on acoustic emission characteristics of induced caving Zhang, Guo-Lian (1); Zhao, Xian-Tao (2) 2012, 33 (9):  1336-1339.  DOI: - Abstract ( 477 )   HTML   PDF (1646KB) ( 568 )   The acoustic emission (AE) characteristics during caving process of rock mass under different geo-stress field and joint distribution were simulated by using RFPA software. It demonstrates that the AE in horizontally jointed roof is concentrated in upper arch corner of stope, and the AE in vertically jointed roof is distributed along the vertical damage surface and shear failure surface. The AE in roof with conjugated joints locates at the joint end along the 45°+φ/2 direction between mined out area and horizontal plane. For the highly stressed rock mass, the AE is distributed along line of caving arch. The AE energy change during the caving process can be divided into two stages, i. e. the first stationary stage and the second catastrophic stage. This result manifests that the energy release rate during the catastrophic stage of AE release is above 5 times of the first stationary stage, which could provide guidance on engineering to predict collapse and caving. References | Related Articles | Metrics

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Research on the optimization of sludge composting process for municipal wastewater treatment plant Xu, Xin-Yang (1); Chen, Xi (1); Liu, Qing (1); Gong, Xuan (1) 2012, 33 (9):  1340-1343+1348.  DOI: - Abstract ( 560 )   HTML   PDF (1978KB) ( 1134 )   Taking the sludge of a Liaoyang sewage treatment plant as an example, a fermentation device with control system was designed to carry out the thermophilic aerobic composting process. The best combination of different index can be obtained by analyzing the parameters such as temperature, water content, pH value, EC, WSOC and NH4+-N of thermophilic aerobic composting process. The investigation shows that it is a better way to dewater the sludge through natural air-drying followed by mixing with conditioners. Among the sawdust, rice husk and rice straw, the compost can achieve the best maturity with sawdust. The best ratio of sludge, sawdust and returned sludge is 3:2:3. Finally, the sludge treated by the thermophilic aerobic composting process can be defined maturity and applied widely according to the experiments of seed germination. References | Related Articles | Metrics

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Application of the interval extension method for the assessment of emergency response capability Pan, Ke (1); Xu, Kai-Li (1) 2012, 33 (9):  1344-1348.  DOI: - Abstract ( 466 )   HTML   PDF (185KB) ( 666 )   In view of the fact that the indicator values are subjective and difficult to be determined accurately because of complex assessment objects and various indicator attributes in the traditional assessment methods, an interval extension evaluation method by using the interval values and the interval correlation function to determine the assessment results was proposed. The assessment index system of the emergency response capability was established according to the characteristics of chemical industry park (CIP) and the requirements of the emergency laws of China. Two-level interval extension evaluation mode was established based on extension set theory and was applied to assessing a certain CIP in Dalian city. It is shown that this method can solve the existing problem of the traditional methods and get more feasible and rational results. This work may provide a reference for the emergency management and assessment of the CIP in China. References | Related Articles | Metrics

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Empirical research on demand structure for knowledge employee of industry-university-research knowledge alliance Sun, Xin-Bo (1); Fan, Mei-Li (1); Liu, Bo (1); Li, Da-Peng (1) 2012, 33 (9):  1349-1352.  DOI: - Abstract ( 610 )   HTML   PDF (1046KB) ( 633 )   Based on literature review and basic assumptions, a model of demand structure was constructed. Questionnaire survey was carried out on the knowledge workers of the industry-university-research knowledge alliance enterprises in the national scope, and the empirical research results indicated that the main demand factors of knowledge workers include explicit demands, tacit demands and active demand. Knowledge worker's sensitivity level of explicit demand factors, tacit demand factors and active demand factors had positive correlation with emerging demand desire. Furthermore, it could be concluded that knowledge workers' individual differences, such as sex, age, education and position, would significantly affect their feel degree of any demand factors. References | Related Articles | Metrics

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Empirical research on the relationship between perceived servicescape and customer citizenship behavioral intention Song, Yang (1); Ma, Qin-Hai (1) 2012, 33 (9):  1353-1356.  DOI: - Abstract ( 674 )   HTML   PDF (1171KB) ( 800 )   In order to study the relationship between perceived servicescape and customer citizenship behavioral intention, the concept model among perceived serviceescape, customer emotion, perceived service quality and customer citizenship behavior in a restaurant was theoretically established based on the environmental psychology. The proposed concept model and hypotheses were tested by the structural equation, which made the following three conclusions. The first, the perceived servicescape will influence the customer citizenship behavioral intention through customer emotions. The second, customer positive emotion has a stronger influence on customer citizenship behavioral intention than that of the customer negative emotion. And the third, restaurant level has moderate effect between perceived servicescape and customer emotion. This study provids the theory basis for enterprises adjusting the servicescape to prompt the produce of customer citizenship behavior. References | Related Articles | Metrics

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Research on the effect of accounting information transparency on corporate investment efficiency Yuan, Zhi-Zhu (1); Wang, Jia-Qiang (2); Li, Jun-Qiang (1) 2012, 33 (9):  1357-1360.  DOI: - Abstract ( 646 )   HTML   PDF (791KB) ( 1114 )   Taken A-share listed companies in the Shenzhen Stock Exchange as sample, the effect of accounting information transparency on corporate investment efficiency was studied on the basis of multiple regression method. Then, based on the perspective of resources allocation efficiency, the economic consequences of accounting information transparency were revealed. The empirical results indicated that accounting information transparency is negatively correlated with overinvestment and underinvestment. That is, higher accounting information transparency can cut down Chinese listed companies' behaviors of overinvestment and underinvestment, and then the investment efficiency is improved. With the existence of financing constraints, the negative correlation between accounting information transparency and underinvestment is more notable. With more free cash flow, the negative correlation between accounting information transparency and overinvestment is more notable. Consequently, the increase of accounting information transparency has a positive effect on optimal capital allocation. References | Related Articles | Metrics

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Revolution surfaces with given mean curvature in 3-D Minkowski space Yang, Yun (1); Yu, Yan-Hua (1); Liu, Hui-Li (1) 2012, 33 (9):  1361-1363+1368.  DOI: - Abstract ( 661 )   HTML   PDF (154KB) ( 650 )   The classification of revolution surfaces with given mean curvature was obtained by studying the corresponding profile curves in three-dimensional Minkowski space. According to the characteristics of the indefinite metric, three types of revolution surfaces in three-dimensional Minkowski space were obtained through a profile curve revolving around spacelike, timelike and lightlike axis, respectively. Assumes that the mean curvatures of these revolution surfaces were certain functions, the corresponding differential equations about the profile curves could be obtained. By solving these differential equations, the classification of the revolution surfaces with given mean curvature were acheived. References | Related Articles | Metrics

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Electronic cleansing in CT colonography: Colon enhancement filtering Xiong, Xin (1); Li, Jun (2); Cai, Jin-Feng (2); Kang, Yan (1) 2012, 33 (9):  1364-1368.  DOI: - Abstract ( 648 )   HTML   PDF (756KB) ( 719 )   CT colonoscopy plays an important role in the early detection of colon cancer. However, because of the partial volume effect of oral contrast agent, electronic cleansing approach tended to suffer from the artifacts of degradation of the soft-tissue structures and the pseudo soft-tissue structures. So, colon enhancement filtering was presented. Firstly, the pseudo soft-tissue was removed by using segment rays in determining initial tagging region phase, then the enhancement function for soft-tissue was constructured with eigenvalue signature of Hessian matrix to enhance the soft-tissue both in air and in the tagging regions. The experimental results show that this method can reduce the degradation of the soft-tissue, remove the pseudo soft-tissue and preserve thin folds sandwiched between air and tagging regions. The overlap between the results by manual and the as-reported segmentations is up to 91.7%. References | Related Articles | Metrics