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15 October 2013, Volume 34 Issue 10 Previous Issue    Next Issue
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Information & Control

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Regional Pole Assignment Robust PID Control Algorithm for DCDC Converter XIAN Yanhua， FENG Jiuchao 2013, 34 (10):  1369-1373.  DOI: - Abstract ( 368 )   HTML   PDF (412KB) ( 720 )   In order to improve the robustness of DCDC converters with disturbances and uncertainties， a robust PID control algorithm was proposed on the basis of the linear matrix inequality (LMI). The PID parameters were tuned by the regional pole assignment(RPA). Taking into account the controlled system robustness against disturbances， the H∞ control was combined with PID control， and solvability condition for the existence of H∞ PID controller was derived in the form of LMI. The designed controller is such that the closedloop system poles are assigned in a specific region in order to obtain anticipant dynamical characteristics， and the closedloop system has an H∞ disturbance attenuation upper bound. Further， the proposed design method can be applied to the DCDC converters with polytopic uncertain parameters. The simulation results of both certain model and uncertain model of buck converters demonstrated the validity and effectiveness of the proposed control strategy. References | Related Articles | Metrics

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Robust Tracking Algorithm Based on Multiple Appearance Models QI Yuanchen， WU Chengdong， CHEN Dongyue， YU Xiaosheng 2013, 34 (10):  1374-1377.  DOI: - Abstract ( 523 )   HTML   PDF (2164KB) ( 610 )   Based on multiple appearance models， a novel multiscale mean shift tracking algorithm was proposed to deal with the problems caused from the relative simplicity of the single appearance model and the absence of the update strategy under the original framework of mean shift tracking. Based on the multiple appearance models which can be obtained by using sparse principal component analysis， numerous converging points were located by running the basic mean shift trackers in parallel. The weighted center was calculated by setting the converging points as the candidate particles， and the best particle was chosen to determine the current state of the object. Experimental results showed that the proposed method was more robust and stable against pose variation， background clutter and occlusion in comparing with other competing tracking models. References | Related Articles | Metrics

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Nodes Lightweight Scheduling Algorithm of Preventing Boundary Contraction in Wireless Sensor Network ZHANG Dongqing， WEN Tao， GUO Quan， SONG Xiaoying 2013, 34 (10):  1378-1381.  DOI: - Abstract ( 493 )   HTML   PDF (1343KB) ( 617 )   The number of boundary nodes neighbors is less than that of the internal nodes in highdensity deployment wireless sensor network， which will lead to unequal probability of sleep and the problem of boundary contraction. To solve the problems， a nodes lightweight scheduling algorithm was proposed to prevent boundary contraction. The number of nodes in neighbor table and the number of neighbor nodes’ working neighbors were used to determine whether the node was in the network boundary. For those boundary and internal nodes， different scheduling strategies were used. The probability of nodes covered completely by n neighbors in the network boundary and the range of area fraction of the boundary node covered by n neighbors were calculated， respectively. The simulation results showed that the boundary contraction can be effectively alleviated and the network life cycle can be extended by using the proposed algorithm. References | Related Articles | Metrics

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Environment Modeling Approach Based on Simplified Visibility Graph ZHANG Qi， MA Jiachen， MA Liyong 2013, 34 (10):  1383-1386.  DOI: - Abstract ( 838 )   HTML   PDF (945KB) ( 1251 )   To solve the problem of establishing environmental model in global path planning for mobile robot， an environment modeling approach was proposed on the basis of the simplified visibility graph. The representation of environmental model was simplified by eliminating obstacles in the environment which do not affect the result of path planning. In the process of environment modeling， the starting point and goal point of mobile robot and the reserved obstacles were used to establish the simplified visible graph in which the quantity of edges is small enough. The visible edges of simplified visible graph were the feasible paths for robot path planning. According to the environmental model established by the simplified visible graph， the efficiency of path planning algorithm was improved. The simulation results demonstrated that the proposed approach is simple and effective. References | Related Articles | Metrics

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Optimization Model and Algorithm for Solving LotSizing Disassembly with Multiresource Constraint GUO Xiwang， LIU Shixin 2013, 34 (10):  1387-1390.  DOI: - Abstract ( 486 )   HTML   PDF (349KB) ( 536 )   For the discarded products disassembly of environmentally conscious manufacturing research field， a method to optimize lotsizing disassembly with multiresource constraints was proposed. A mathematical model was established to minimize the time of disassembly， and the software of CPLEX was used to solve this model. Simulation results of several randomly generated problem instances validated the effectiveness of the proposed model， which indicated that the optimal disassembly quantity， the purchase quantity， and whether a component needs to be disassembled could be solved. What’s more， the external demand of each component could be satisfied at the same time. It could be concluded that there exists influence on the difficulty of solving the lotsizing disassembly problem from the indegree and outdegree of nodes and the percentage of common components. References | Related Articles | Metrics

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Evacuation Algorithm Design and System Implementation in Major Accident JIN Xi， JIANG Zhiyu， ZHANG Xue， DENG Qingxu 2013, 34 (10):  1392-1395.  DOI: - Abstract ( 508 )   HTML   PDF (501KB) ( 606 )   An internet of things system was presented to solve the problem of how to effectively and efficiently evacuate the working staff in major accidents. Based on the proposed system， an efficient evacuation route search algorithm (ERSA) was also proposed to reduce the evacuation time， by which the evacuation route could be iteratively found on the basis of the distribution of roads and people within a prescribed time limit. Experimental results showed that compared with shortest path evacuation algorithm and random path evacuation algorithm， better evacuation routes could be generated by the proposed ERSA and evacuation time could be reduced by 15% and 28%， respectively. References | Related Articles | Metrics

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Modeling and Topological Features Analysis of DBLP Coauthor Network JIA Siyuan， XU Yong， ZHAO Hai， AI Jun 2013, 34 (10):  1396-1399.  DOI: - Abstract ( 749 )   HTML   PDF (2451KB) ( 906 )   Using the DBLP computer science bibliography as raw data， the coauthor network of the computer and related fields was studied. By parsing the extracted xml metadata， the coauthor network topology was constructed， and the general parameters of the network topology were calculated. In addition， the statistical characteristics of a number of parameters were analyzed， which could be found that the DBLP coauthor network is a typical smallworld network yet with no obvious scalefree property. Different research cooperation modes were reflected by the topologies of center and bordering of the network， and there is no strong correlation of the kcore of the network with the scientist’s hindex. The development of complex network and the positioning of our lab in the computerrelated field at the academic level were finally discussed. References | Related Articles | Metrics

Materials & Metallurgy

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Effects of Trace Ga on Microstructure and Specific Capacitance of Aluminum Foils Used for Capacitor Anodes ZUO Hong， LI Xinfang， LIU Chunming 2013, 34 (10):  1400-1403.  DOI: - Abstract ( 503 )   HTML   PDF (3603KB) ( 719 )   The cubic texture of the annealed high purity aluminum foils with trace Ga used for the anode of high voltage electrolytic capacitors was quantitatively characterized by Xray diffractometer (XRD). The microstructures of their hotrolled plates and final annealed foils were observed by optical microscope(OM) and scanning electron microscope (SEM). The corrosion structures of the etched foils were quantitatively analyzed with image analysis software. Based on the above experiments the effects of the mass fraction of trace Ga on the microstructures and the corrosion structure as well as the specific capacitance were investigated. The results showed that with the mass fraction of Ga increasing from 05×10-6 to 116×10-6， the volume fraction of cubic texture in the foils decreased slightly， but the specific capacitance of the foils measured at 520V increased from 0662μF/cm2 to 0706μF/cm2. Further increasing the mass fraction of Ga to 214×10-6 did not affect the microstructure and the fraction of the cubic texture， but the specific capacitance dropped to 0693μF/cm2. Adding trace Ga promoted the electrochemical pitting and resulted in the enlargement of the specific surface area of the foil and the improvement of the specific capacitance. However when the mass fraction of Ga was higher than 116×10-6， obvious pit merging occurred， the specific surface area of the foil reduced and the specific capacitance decreased. References | Related Articles | Metrics

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Effects of Smelting Process on Microstructure and Properties of TM210A Steels ZHAO Suwu， LIU Chunming 2013, 34 (10):  1404-1407.  DOI: - Abstract ( 827 )   HTML   PDF (1242KB) ( 966 )   Because of practical condition that the microstructure and properties of the TM210A maraging steel didn’t meet the requirements from the standard， the effects of chemical composition and the remelting rates in vacuum consumable electrode on the macrostructure and the mechanical properties of the TM210A steel bars were investigated. The microstructures of the steel bars after solidsolution and aging treatments were observed by transmission electron microscopy (TEM). The experimental results showed that the reasonable control of the contents of the strengthening elements increased the strength of the bar， and the appropriate remelting rate in vacuum consumable electrode also effectively improved the macrostructure quality and the strength of the bar. The smelting processes of the steels were established according to the above results. References | Related Articles | Metrics

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Preparation and Electrochromic Properties of TiO2 Films Doped Ce and Sm NIU Wei， BI Xiaoguo， SUN Xudong 2013, 34 (10):  1409-1411.  DOI: - Abstract ( 502 )   HTML   PDF (380KB) ( 638 )   TiO2 films doped Ce and Sm were prepared by solgel methods with butyltitanate(Ti(OC4H9)4)， cerium nitrate(Ce(NO3)3·6H2O) and samarium nitrate(Sm(NO3)3·6H2O) as main raw materials on the ITO conductive glass substrate. The molar fractions of Ce and Sm are 0， 2%， 5% and 10%， respectively. Cyclic voltammetry and optical properties were studied using the electrochemical workstation and ultraviolet visible spectroscopy. The results showed that the film had the largest peak current and strongest ion storage capacity when Ce and Sm doping content was 2%， the injection charge density was up to 1512mC·cm-2and K value was 07. When the contents of Ce and Sm increased to 5% and 10%， the peak current decreased and the charge storage ability reduced with the increase contents of Ce and Sm. The colored state of TiO2 films doped Ce and Sm was pretty shallow. Transmittance was more than 90% in both the colored state and bleached state. Therefore TiO2 films doped Ce and Sm had good transparency in the visible light range and would be used as ion storage materials in the electrochromic glass. References | Related Articles | Metrics

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Effect of Annealing Modes on Microstructure and Properties of Boron Containing ColdRolled DeepDrawing Enamel Steel DONG Futao， DU Linxiu， LIU Xianghua， XUE Fei 2013, 34 (10):  1412-1415.  DOI: - Abstract ( 494 )   HTML   PDF (2838KB) ( 658 )   The effect of two annealing modes (batch annealing and rapid continuous annealing) on the microstructure， mechanical properties and fishscale resistance of boron containing enamel steel was investigated. The results showed that appropriately increasing the mass fraction of Mn， S and adding trace boron， both the tested steel sheets under the two annealing modes had good properties. The strength of the continuous annealed sheet was slightly higher， and the elongation A50 and rmvalues of the continuous annealed sheet were apparently higher than that of the batch annealed sheet. The continuous annealed sheet showed better comprehensive mechanical properties. The hydrogen diffusion rate in the continuous annealed sheet was much lower than that in the batch annealed sheet. This was mainly attributed to large amount of dispersed cementite particles precipitate within ferrite grains which can act as effective hydrogen traps in the ultrafast continuous annealing steels. The match of good mechanical properties with fishscale resistance of the boron contained enamel steel was realized through rapid continuous annealing process. References | Related Articles | Metrics

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Effects of Oxide Scale on Industrial Atmosphere Corrosion of Low Carbon Steels HE Yongquan， SUN Bin， LIU Zhenyu， LI Jun 2013, 34 (10):  1416-1419.  DOI: - Abstract ( 470 )   HTML   PDF (1659KB) ( 921 )   Effects of the layerstructure oxide scale on the industrial atmosphere corrosion of hotrolled low carbon steels were investigated by wet/dry cyclic corrosion test. The corrosion weight gain， corrosion product structure and electrochemistry behavior of the specimens with the oxide scales were analyzed compared with that of the specimens without the oxide scales through scanning electron microscopy (SEM) and electrochemistry methods. It was found that the corrosion rate of the samples with oxide scale was lower than that of the naked steel. Polarization curves indicated that the samples covered with oxide scale had a lower corrosion potential than that of the naked steel. Single phase layered structure oxide scales had a good corrosion resistance that kept the substrate steel from corrosion. The integrity of oxide scale was the crucial prerequisite that the oxide scale protect the substrate steel. If the oxide scale was broken， galvanic corrosion will happen between the iron oxide and the substrate steel at the location of defects. References | Related Articles | Metrics

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Experiment Method to Simulate Internal Cracks and Its Healing Behavior of Rolled Pieces LIU Xianghua， AI Zhengrong， YU Hailiang 2013, 34 (10):  1420-1424.  DOI: - Abstract ( 466 )   HTML   PDF (3439KB) ( 691 )   A new experiment method called hole filling method was proposed to simulate the internal cracks inside rolled pieces. The healing behavior of internal cracks in a mild steel plate during rolling was studied by presetting internal cracks in a sample. The crack healing tests in the center and 1/3 height of the plate were carried out. The results showed that internal cracks heal completely at the reduction of more than 50%and the rolling temperature 1100℃. The crack in the center of the plate healed better than that at other places， and cooling slowly after rolling was good for healing. The mechanism of crack healing in the rolling processes was analyzed. During the rolling deformation， the compressive stress state provides the static condition for crack healing. When the plastic deformation went on， as the huge atoms move towards one direction， which provided the material supply condition for crack healing， the atoms on two sides of the crack are easy to find a stable location to form a crystal lattice， then the crack heal. References | Related Articles | Metrics

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Rolling Force Model Considering Phase Transformation for Hot Strips During Finishing Process LI Weigang， CHEN Shuixuan， LIU Xianghua 2013, 34 (10):  1425-1429.  DOI: - Abstract ( 565 )   HTML   PDF (1003KB) ( 954 )   When phase transformation occurs during the finishing process for hot strips， the change regulations of the rolling temperature on the deformation resistance in the austenitic and ferrite are different， so the prediction error of traditional rolling force model is very significant， which impacts the control accuracy of rolling process parameters. To solve the problem， a rolling force model was developed considering phase transformation for finishing strips. First， a transformation volume fraction model in the form of cosine was established and the volume fractions of the ferrite and austenitic were calculated at the different rolling temperatures. Secondly， an effect formula of the rolling temperatures in weighting form on the deformation resistance was presented， which preferably simulated the deformation characteristics of the doublephase rolling. Finally， the proposed model was applied to the online calculation of Baosteel 1880mm HSM， the actual production showed that the proposed model significantly improved the rolling force prediction accuracy and rolling stability of the phase transformation strips such as nonoriented electrical steels in the finishing process. References | Related Articles | Metrics

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Formation Mechanism of 2CaO·SiO23CaO·P2O5 Solid Solution SU Chang， YU Jingkun， WANG Hongzhang 2013, 34 (10):  1434-1437.  DOI: - Abstract ( 552 )   HTML   PDF (1500KB) ( 676 )   The reaction process of CaOSiO2FetOP2O5 slag with solid CaO was investigated by immerging solid CaO into CaOSiO2FetOP2O5 molten slag under 1300℃.The activity of each compound in slag was calculated by the coexistence theory of molecule and ion， and the formation mechanism of 2CaO·SiO23CaO·P2O5 solid solution was discussed. The results showed that the components of CaOSiO2FetOP2O5 slag existed mainly in forms of 2CaO·SiO2 and 3FeO·P2O5 in molten slag. When the solid CaO contacted with the slag， 2CaO·SiO2 first precipitated on the surface of the solid CaO and formed 2CaO·SiO2 solid layers， then CaO and 3FeO·P2O5 continuously diffused into the interface between the CaO and 2CaO·SiO2 layer， thus the 2CaO·SiO23CaO·P2O5 and CaOFeO solid solutions were formed. References | Related Articles | Metrics

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Analysis of Influence Factors on Energy Consumption in Chinese Steel Industry from 1995 to 2010 CAI Jiuju， YE Zhu， SUN Wenqiang 2013, 34 (10):  1438-1441.  DOI: - Abstract ( 554 )   HTML   PDF (386KB) ( 801 )   Based on the data of energy consumption and steel production of Chinese steel industry from 1995~2010， factor decomposition was conducted to analyze energy consumption by using logarithmic mean Divisia index method， including energy consumption structure， energy consumption per ton of crude steels and production. The results showed that energy consumption increased 3596700tce in total from 1995 to 2010. The variety steel production contributed the biggest part of the steel industry energy consumption， accounting for 15750%. The energy consumption per ton of crude steel took second place on the contribution of the energy consumption， accounting for -5753%. The last effect part was energy structure， which only contributed for 003% of the energy consumption. Thus， it is a key method to realize energy conservation by decreasing the energy consumption per ton of crude steels. There was a drop of 40435kgce/t of the energy consumption per ton of crude steels from 1995 to 2010， among which 2937% and 7063% of the drop came from steel ratio coefficients and process energy consumption， respectively. References | Related Articles | Metrics

Mechanical Engineering

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SelfSynchronous Theory of Novel NoSwing Vibrating Mechanism Driven by Two Motors LI He， LIU Dan， LI Ye， WEN Bangchun 2013, 34 (10):  1446-1450.  DOI: - Abstract ( 517 )   HTML   PDF (641KB) ( 555 )   The motion and stability conditions of selfsynchronization were studied for a novel noswing vibrating mechanism driven by two motors. The vibrating mechanism comprises an inner rigid frame and an outer rigid frame. The rotational centers of two eccentric rotors are in line with the inner rigid frame center of mass along a vertical axis. Therefore the moment generated by the inertial force of eccentric rotors to the vertical axis is zero， thus eliminating the swing of the vibrating mechanism. The differential motion equations of the vibrating mechanism were established by the Lagrange equation， and the dimensionless coupled motion equation of the eccentric rotors was obtained with the modified average small parameter method. The existence condition of zero solution for the dimensionless coupled motion equation of the eccentric rotors was used to achieve the condition to implement selfsynchronous motion of the vibrating mechanism， and the RouthHurwitz criterion was used to derive the stability conditions of selfsynchronous motion. The numerical simulations verify the correctness of the proposed theories. References | Related Articles | Metrics

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Incremental Harmonic Balance Method for Coupled Bending and Torsional Vibration in Planetary Gear System YAO Hongliang， XU Qi， MAO Lieqian， WEN Bangchun 2013, 34 (10):  1451-1454.  DOI: - Abstract ( 589 )   HTML   PDF (978KB) ( 738 )   Incremental harmonic balance (IHB) method could not solve the coupled bending and torsional vibration equation of positive semidefinite in planetary gear transmission mechanism directly， and microrelative displacement was applied to describe relative motion between the parts in the planetary gear system. The motion transfer matrix was used to transform positive semidefinite equation into positive definite equation. Meanwhile， considering the timevarying nonlinear characteristics of gear mesh stiffness， the IHB method was used to analyze the nonlinear dynamics response in the planetary gear system. The correctness and efficiency of the proposed method were verified by comparison with Newmarkβ method. References | Related Articles | Metrics

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Inner Magnetic Field Characteristics of Giant Magnetostrictive Actuator Considering Permittivity Effects LI Dong， YUAN Huiqun， LI Zhijun， LI Ying 2013, 34 (10):  1456-1460.  DOI: - Abstract ( 464 )   HTML   PDF (1030KB) ( 688 )   Based on the Maxwell’s equation， the inner magnetic field radial distribution model of giant magnetostrictive actuator was built by combining with piezomagnetic equations， in which the permittivity， compressive prestress of the material were introduced. The theoretical analysis and numerical simulation of the model were done， and the influences of the material characteristic parameters on the material inner magnetic field and hysteresis characteristics were discussed. The results showed that the inner magnetic field radial distribution of giant magnetostrictive material (GMM) has obvious skin effect and hysteresis characteristics. Under the effects of conductivity and permittivity， the phenomenon of dualpeak is found in magnetic field distribution of GMM. Along with the radius direction of GMM， the hysteresis characteristics between excitation magnetic field and inner magnetic field gradually become weak， and the magnetic loss decreases. The skin effect of GMM decreases with the increase of compressive prestress. References | Related Articles | Metrics

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Automatical Optimization of AeroEngine PipeRouting Layout Based on ABC Algorithm ZHANG Yu， BAI Xiaolan， WU Pengrui 2013, 34 (10):  1461-1464.  DOI: - Abstract ( 513 )   HTML   PDF (1115KB) ( 603 )   The artificial bee colony (ABC) algorithm was introduced to solve problems of the piperouting layout for aeroengine. By setting the maximum number of path nodes， adopting the grid division and engineering rulesguided search strategies and using the tournament selection strategy， problems of the unfixed path node， neighborhood construction difficulties and premature convergence and stagnation of the aeroengine piperouting layout were discussed on the basis of the ABC algorithm， respectively. An ABC algorithm for the automatical optimization of aeroengine piperouting layout was proposed， and the case study showed the feasibility and effectiveness of the algorithm. References | Related Articles | Metrics

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Machining Accuracy Distribution Regularities of CNC Milling Machining Center FAN Zhiguang， GONG Yadong， WANG Chao， LYU Wei 2013, 34 (10):  1465-1468.  DOI: - Abstract ( 644 )   HTML   PDF (557KB) ( 773 )   To test the machining accuracy distribution of CNC milling machining center， an orthogonal experimental scheme was presented on the basis of the orthogonal test design theory and the characteristics of CNC machining technology. The scheme was used to machine variable diameter cams and then the line profiles of the cams were simulated using Matlab. The results showed that the line profile accuracy has a normal distribution. The relatively larger line profile errors， R2 and R5， were analyzed using the extreme difference analysis method in order to study the influence of machining parameters. The profile tolerance value should be different for every arc of the same part. References | Related Articles | Metrics

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Resistive Switching of EuRu Codoped NiOSnO2 Composite Nanoparticle Thin Films LI Jianchang， WANG Yulei， XU Bin， HOU Xueyan 2013, 34 (10):  1469-1472.  DOI: - Abstract ( 625 )   HTML   PDF (1276KB) ( 571 )   EuRu codoped NiOSnO2 composite nanoparticle thin films were prepared using solhydrothermal spincoating method. The film structural and electrical properties were characterized by transmission electron microscopy， atomic force microscopy and currentvoltage measurements. The results indicate that the film surfaces are flat and smooth with average roughness of about 025nm. The data of Miller indices and interplanar spacings from the selected area electron diffraction are consistent with that from the XRD card of NiO or SnO2， and the hydrothermal mechanism also shows that nanoparticles are composed of microscale pn junctions of NiOSnO2. The nanoparticle films exhibit reproducible resistive switching with threshold voltage of about 1V and on/off ratio of 500. The currentvoltage measurements indicate that the conduction is governed by the Ohmic law for the low resistive state， while the high resistive state is dominated by the space charge limited conduction. The switching mechanism can be ascribed to the charge trapping/detrapping process induced by the applied threshold electrical field. References | Related Articles | Metrics

Resources & Civil Engineering

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Elimination of Copper and Iron Cyanide Complexes and Mechanism in Hypersaline System LI Mingyang， WEI Dezhou， LIU Wengang， SHEN Yanbai 2013, 34 (10):  1473-1476.  DOI: - Abstract ( 597 )   HTML   PDF (633KB) ( 1135 )   In order to solve the problem that the presence of copper cyanide complexes (CuCN2-3 and CuCN3-4)and iron cyanide complex (FeCN4-6) in lixivium increases the consumption of NaCN and activated carbon in the process of gold ore cyanide leaching， the forms of copper and iron cyanide complexes in hypersaline system were discussed preliminarily， and the elimination efficiencies of these complexes by three different methods， i. e. the hydrogen peroxide oxidation， the chlorine oxidation and the acidification， were comparatively analyzed. The results showed that the elimination efficiencies of the copper cyanide complexes are over 99% by the three methods， while that of iron cyanide complex are 73%， 62% and 55%， respectively. The protonation is more effective for the elimination and decomposition of copper cyanide complexes and iron cyanide complex than oxidation in hypersaline system. References | Related Articles | Metrics

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Morphology of PAFCC Prepared by Coal Gangue Leaching Method HE Lili， XU Xinyang 2013, 34 (10):  1477-1480.  DOI: - Abstract ( 368 )   HTML   PDF (1630KB) ( 633 )   The morphological structure and characterization of the polymeric aluminum ferric chloride calcium(PAFCC) flocculant were studied using TEM，EDS，IR spectroscope and Xray diffraction analysis techniques. The morphology，feature groups and microcrystalline phase structure of noncalcined synthetic products and calcined synthetic PAFCC products were compared. The results showed that the calcined products are silicic acid (aluminum) substance with high activity and the noncalcined synthetic products are compound mainly contained sodium，aluminium，iron，calcium，chlorine and other elements with short columnar crystal morphology. PAFCC has hollow tube of columnar crystals morphology and it is an inorganic polymer which has chloride，aluminum ferric polyhydroxy. The calcination process enhanced coal gangue activity and played an important role in the synthesis process of PAFCC. Using kaolin wastewater，the coagulation effect of PAFCC is superior to that of noncalcined synthetic products and PAC. References | Related Articles | Metrics

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Effect of Activated Carbon on Oxidative Activity in Growth of Thiobacillusferrooxidans FENG Yali， CHENG Yulong， LI Haoran， ZHOU Yuzhao 2013, 34 (10):  1481-1483.  DOI: - Abstract ( 497 )   HTML   PDF (480KB) ( 575 )   When other nutrients were sufficient in cultivation of the thiobacillusferrooxidans， the effect of mass concentration of activated carbon on the growth activity of thiobacillusferrooxidans was studied， and the bacterial growth curves were obtained at different activated carbon mass concentrations. The experimental results showed that the activated carbon can promote the oxidative activity of thiobacillusferrooxidans in a certain concentration range. When the activated carbon concentration is less than 80g/L， it has a promoting effect on bacterial oxidative activity; when the concentration is 60~80g/L， the promoting effect is the biggest; when the concentration is larger than 100g/L， the growth of thiobacillusferrooxidans is completely inhibited. By researching the timevariation of ρ(Fe2+) and ρ(Fe3+) during the sterile control experiment， the results showed that the activated carbon has little effect of oxidation on Fe2+when the activated carbon concentration is less than 80g/L. References | Related Articles | Metrics

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Damage and Failure Mechanism of Tunnels in Jointed Rock Mass MA Tianhui， ZHANG Wendong， XU Tao 2013, 34 (10):  1485-1489.  DOI: - Abstract ( 625 )   HTML   PDF (3077KB) ( 747 )   In consideration of the the variation of mesoscopic patterns of joints， the damage process of surrounding rock of an underground opening in jointed rock mass was numerically simulated， and the failure mechanism of surrounding rock was investigated. The effect of the dip angles of joints on the stability of surrounding rock was examined. The results showed that the tensile stress causes mainly the initiation and propagation of the cracks， and the propagation direction of the cracks is roughly normal to the joint surface. The tensile cracks normal to the joint surface are the dominant fracture behaviors around the opening in the rock model with a low joint dip angle， while， the joint sliding are the dominant in the model with a high joint dip angle. The dip angle of joint surfaces also affects the fragility of rock mass. With the initiation of microfracture before the rock failure， a lot of energy will be released as acoustic emission. By using microseismic monitoring technology to get the information of energy release， the collapses， roof falling， rock burst and other disasters can be possibly forecasted， thus the supporting measures could be taken in advance to keep staff and equipment safe. References | Related Articles | Metrics

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Effects of Trolley Horizontal Stiffness on Structure Dynamic Performance of Retractable Roof MU Zaigen， LUAN Haiqiang， LIU Guoyue， FAN Zhong 2013, 34 (10):  1490-1494.  DOI: - Abstract ( 385 )   HTML   PDF (2391KB) ( 659 )   Taking the retractable roof structure of national tennis court “diamond stadium” as the analysis object， the effects of trolley horizontal stiffness on structure natural vibration characteristics and seismic responses of the retractable roof were comparatively studied using the finite element software SAP2000. The results showed that， with trolley horizontal stiffness decreasing， the structure natural period of vibration increased， and the horizontal and vertical displacements of the retractable roof track beam decreased， correspondingly. In addition， the trolley horizontal stiffness can influence the axial force of fixed roof and retractable roof bars， and it is more obvious on the fixed roof bars axial force. Therefore， the influence of the trolley horizontal stiffness should be considered in design and application of this kind of structure. References | Related Articles | Metrics

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Slope Stability of Landfill Under Biodegradation QIU Gang， LIANG Li， SUN Hongjun 2013, 34 (10):  1495-1498.  DOI: - Abstract ( 492 )   HTML   PDF (2809KB) ( 503 )   In consideration of the change of physical and mechanical properties of waste body with the time and the degree of degradation， the landfill was divided into five different degradation areas， different cohesions and internal friction angles were specified in order to study the influence of the biodegradation of waste body on landfill slope stability. The safety factor of the landfill site was calculated using FLAC3D， and the failure mechanism of landfill slope stability was analyzed. The landfill slope stability was examined through a couple of instances， and the calculation result of the numerical method is lower than the result with the limit equilibrium method. This method can predict the local bucking failure of landfill under complex boundary conditions and the failure caused by extremely big displacement of slope. And it should be more useful for the analysis of the stressstrain failure mechanism. References | Related Articles | Metrics

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Evaluation on Activity of Ceramic Polishing Powder and Its Effect on Compressive Strength of Concrete CHENG Yunhong， HUANG Fei， LI Guanglu， QIN Zhisheng 2013, 34 (10):  1499-1503.  DOI: - Abstract ( 644 )   HTML   PDF (3876KB) ( 655 )   The activity of ceramic polishing powder was tested and evaluated by activity test. Taking ceramic polishing powder as supplementary cementing materials for concrete， the effects of the ceramic polishing powder on concrete compressive strength was studied. It is showed that the ceramic polishing powder possesses reaction activity， it can interact with Ca(OH)2， i. e.， secondary hydration reaction. The development trend of compressive strength of ceramic polishing powder concrete with age is similar to that of plain concrete. The concrete compressive strength at different ages declines with increasing mass fraction of cement replaced with ceramic polishing powder. If the mass fraction of replacement is not more than 30%， the strength grade of concrete can be at the level of C30 or C40. Finally， with the same mass fraction of replacement， the compressive strength of ceramic polishing powder concrete approximates to fly ash concrete at different ages. References | Related Articles | Metrics

Management Science

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Institutional Distance， Information Asymmetry and International M&A Performance:Empirical Evidence from Chinese Listed Companies DU Xiaojun， ZHU Yuanyuan 2013, 34 (10):  1504-1507.  DOI: - Abstract ( 514 )   HTML   PDF (410KB) ( 910 )   Based on the liability of foreignness theory and using the stepwise linear regression method， the key factors to influence the international merger and acquisition performance were studied using the examples of Chinese listed companies. The results showed that if enterprise heterogeneity and host country institutional quality etc.， are regarded as the control variables， there is an obvious negative correlation between the legal institutional distance and the international M&A performance， while the economic institutional distance and cultural distance could promote the international M&A performance. The population densities of acquirers can adjust the correlation between the institutional distance and the performance. References | Related Articles | Metrics

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Effectiveness of Incentive Synergy in Knowledge Alliance SUN Xinbo， XIE Yuanrui， QIAN Yu 2013, 34 (10):  1508-1511.  DOI: - Abstract ( 541 )   HTML   PDF (313KB) ( 539 )   By exploring the links between balanced scorecard principle and knowledge alliance， a validity evaluation index system of incentive synergy was established on the basis of the balanced scorecard principle. According to the relevant index system， a fuzzy comprehensive evaluation model was built to evaluate the validity of incentive synergy. The data from a knowledge alliance that composed of a college and a software development enterprise in Liaoning Province were obtained by questionnaire survey， and the weight of each index was determined by analytic hierarchy process. Finally， the effectiveness of incentive synergy was evaluated with the established fuzzy comprehensive evaluation model. References | Related Articles | Metrics

Biologic Engineering

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Quantitative Analysis of Pharmacokinetic Parameters Using Clinical Lung Dynamic ContrastEnhanced MR Image ZHONG Yi， LI Zhiyong， HU Jiani， KANG Yan 2013, 34 (10):  1512-1516.  DOI: - Abstract ( 543 )   HTML   PDF (880KB) ( 585 )   Based on the dynamic contrastenhanced MRI (DCEMRI) data routinely acquired from a clinical lung， a new method called FCMB RR was proposed for quantitative analysis. This method was based on the reference region model (RR)， and combined with fuzzy Cmean (FCM) and BSpline curve fitting techniques. The proposed FCMB RR method not only solved the limitation of complex blood supply system， but also reduced the effect of noise on the quantitative analysis result. 5 patients with pathologically proven lung cancer were examined using the proposed FCMB RR method to demonstrate the feasibility and effectiveness. A significant difference (P<001) in Ktransbetween tumor tissue and normal tissue was found. It could be concluded that the proposed FCMB RR method could be used for quantitative analysis of typical clinical lung DCEMRI data， and the Ktrans information has reference value for treatment and assesses the lung cancer. References | Related Articles | Metrics

Mathematics

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Affine Translation Surfaces in Minkowski 3DSpace YUAN Yuan， MA Longbiao， LIU Huili 2013, 34 (10):  1517-1519.  DOI: - Abstract ( 577 )   HTML   PDF (298KB) ( 657 )   Special surfaces in the Minkowski space were studied on the basis of the invariant theory and theory of differential equation. Some categories were presented by changing the partial differential equation into the ordinary differential equation to simplify the solving process. Affine translation Weingarten surfaces were studied under the pseudo orthogonal frame. The first and second fundamental forms， Gaussian curvature and mean curvature of the surfaces were obtained according to the basic principles of differential geometry. The classification theorems of those translation surfaces were given mainly by using the linear and square relationships between the Gaussian curvature and the mean curvature. References | Related Articles | Metrics