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15 April 2013, Volume 34 Issue 4 Previous Issue    Next Issue
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Information & Control

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New Stability Criteria for Linear Systems with TimeVarying Delay ZHENG Lianwei， SONG Shuni 2013, 34 (4):  457-460.  DOI: - Abstract ( 501 )   HTML   PDF (387KB) ( 887 )   On the assumption that the delay is timevarying and ranges in an interval， the stability of linear systems with a delay was studied. Based on a LyapunovKrasovskii functional of quadratic type， a new stability criterion dependent on the delay range was proposed by employing the convex combination of integrals and Jensen’s integral inequality. Partitioning the delay range into segments， the coefficients of integral terms in the derivative of the LyapunovKrasovskii functional were enlarged by using appropriate inequalities for each segment. The conservatism of the convex combination method was reduced due to not using unified inequality for different segments. Theoretical analysis and numerical examples showed that the result obtained had less conservatism than that of some existing ones. References | Related Articles | Metrics

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H∞ Optimal Control by Output Feedback for Singular Systems YANG Dongmei， XU Wenming， CUI Lei 2013, 34 (4):  461-464.  DOI: - Abstract ( 600 )   HTML   PDF (386KB) ( 782 )   Based on the method of LMI， H∞ optimal control by dynamic output feedback was studied for the standard control model of the generalized system. The general solution of ETX=XTE was used for several congruent transformations and variable substitutions of the matrix in the inequality. Then the necessary and sufficient condition for the presence of the controller was given. What’s more， the design method was given for the controller. Finally， a corresponding numerical example was presented to illustrate the effectiveness of the proposed method. References | Related Articles | Metrics

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DiscreteTime Sliding Mode Controller Design Based on Output Feedback WANG Hongwei， YU Chi， WANG Suxin 2013, 34 (4):  465-468.  DOI: - Abstract ( 576 )   HTML   PDF (448KB) ( 860 )   An improved output feedback variable structure controller was designed for a class of multiinput multioutput (MIMO) uncertain discretetime systems. The stable sliding surface was designed on the basis of the pole assignment method. Then， the advantages and disadvantages of the traditional discretetime exponential approximation law were analyzed. A modified discretetime exponential approximation law was presented on the basis of the sliding mode control condition. The designed control law could ensure quickly the state response of the system and chattering could be reduced at the same time. When the states were not fully measured， the proposed controller had a good performance. The simulation results verified that the proposed algorithm was feasible and effective. References | Related Articles | Metrics

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Modeling and Manipulation Based on AFM Pushing for Nanorod WU Chengdong， HOU Jing， DONG Zaili， LI Mengxin 2013, 34 (4):  469-473.  DOI: - Abstract ( 712 )   HTML   PDF (570KB) ( 553 )   The behavior of nanorod driven by AFM was analyzed， and a kinematics model of nanorod was established by introducing viscous friction which is relevant with the pushing velocity. Based on the model， the planning about the pushing parameters of AFM was debated and the nanohand strategy of zigzag stable pushing was presented to solve the problems raised by only one end effector of AFM and the uncertainty of nano scale. The simulation and experimental results showed that the instantaneous centre of nanorod at each manipulation could be determined by the kinematics model in real time. At the same time， the rod could be pushed into a bounded target area within a given probability by the nanohand strategy of zigzag stable pushing. So the stable and posture controllable nanomanipulation could be realized. References | Related Articles | Metrics

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Hand Gesture Tracking Method Based on Kalman Filter and Skin Color Feature TAN Wenjun， YANG Jinzhu， WANG Li， ZHAO Dazhe 2013, 34 (4):  474-477.  DOI: - Abstract ( 532 )   HTML   PDF (558KB) ( 2397 )   The effective and robust hand gesture tracking is the premise of the dynamic hand gesture recognition. According to the characteristics of hand gesture movement， a hand gesture tracing method was presented on the basis of the Kalman filter and the skin color model. Firstly， the hand movement target was recognized with the background difference and the skin color model. At the same time， the movement parameters of Kalman filter were set by the parameters of spatial structure. Then， the tracking matching function based on the feature of spatial structure was calculated to correct the target predicted position， and the target region of dynamic hand gesture and its motion track were also got. The results showed that the proposed method was effective， accurate and robust to track hand gesture and was adapted to hand change， turning path and other situations. References | Related Articles | Metrics

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Improved Two Dimensional Sweep Algorithm for Airpot Shuttle Service with Lowest Carbon Emission YANG Peiying， TANG Jiafu， YU Yang 2013, 34 (4):  478-481.  DOI: - Abstract ( 548 )   HTML   PDF (380KB) ( 745 )   Under the background of the airport shuttle service， a method to decrease vehicle carbon emissions was studied by management optimization. On the basis of quantitative analysis of vehicle carbon emissions， the mathematical model of lowcarbonemission shuttle service was established. After analyzing classic scanning algorithm， an improved two dimensional sweep algorithm (ITDSA) was proposed for both time dimension and space dimension in the lowcarbonemission airport shuttle services. After calculating the instance using the improved two dimensional sweep algorithm and analyzing the experiment results， the relationship between customer satisfaction factor and carbon emissions in the airport shuttle service was explored. The results showed that the carbon emissions were relatively lower while the customer satisfaction factor was set as 85%. References | Related Articles | Metrics

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Cloud Resource Allocation Method and Bidding Strategy Based on Simultaneous Upward Bidding Auction WANG Xueyi， WANG Xingwei， HUANG Min 2013, 34 (4):  482-485.  DOI: - Abstract ( 770 )   HTML   PDF (598KB) ( 1134 )   On account of the characteristics of cloud resources， a cloud resource allocation method and bidding strategy were proposed on the basis of the microeconomic method and support vector regression method. Firstly， the block ability was used to describe buyer demand and seller resources. Secondly， the system architecture of cloud resource was constructed， and according to the resource transaction history of each buyer， their bidding price was predicted by using support vector regression method. Based on the above， according to Nash equilibrium theory of incomplete information， simultaneous upward bidding auction was designed， and the final transaction price was formed. What’s more， cloud resources were allocated by the final transaction price. Simulation results showed that the proposed method and strategy were feasible and effective. References | Related Articles | Metrics

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Construction of DICOM SR Relational Database Based on Foggy Diagnostic Model and Representation with XML FENG Xue， MA Zongmin 2013, 34 (4):  486-489.  DOI: - Abstract ( 670 )   HTML   PDF (449KB) ( 912 )   Along with the indepth application of PACS， deeper requirement are put forward by the system users that medical images can be retrieved intelligently， but not just being managed. In order to fulfill intelligent retrieval of medicine images， a SR relational database model was proposed on the basis of foggy diagnostic model. The model was based on fuzzy theory， which could be a very good representation of uncertain information in diagnostic language for medical images. On this basis， the mapping method from the proposed relational databases to XML documents was studied， by which the XML expression of SR information was realized. The foundation was laid for the next intelligent retrieval of medical images by using the proposed model. References | Related Articles | Metrics

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Detecting Topical Opinion Leaders Based on LDA Model in Chinese Microblogs FENG Shi， JING Shan， YANG Zhuo， WANG Daling 2013, 34 (4):  490-493.  DOI: - Abstract ( 811 )   HTML   PDF (486KB) ( 1767 )   How to effectively detect the opinion leaders in the Chinese microblog space has become a hot research problem in the related area. To tackle this issue， an algorithm combined LDA model and HowNet was proposed to classify the short texts in microblogs based on their underlying subtopics. Then an influence measurement containing the criteria on explicit， implicit and user features was introduced. An analytic hierarchy process method was employed to assign different weight of each parameter. Experiment results showed that the proposed short text classification method outperformed the traditional SVM based method， and the proposed influence measurement model could effectively detect the opinion leaders in the Chinese hot topic microblogs. References | Related Articles | Metrics

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Robust ScaleFree LT Code and Its Performance ZHAO Yuli， ZHU Zhiliang， YU Hai 2013, 34 (4):  495-499.  DOI: - Abstract ( 663 )   HTML   PDF (695KB) ( 934 )   Degree distribution used for generating encoded symbols is the key problem for designing LT code. A complex network was constructed on the basis of the message traveling principle of the decoding process. A robust scalefree LT code was proposed by applying properties of scalefree network， such as shortest average path length. The results indicated that there were better performances in encoding/decoding efficiency， overhead factor， probability of successful decoding of robust scalefree LT code than those of LT codes based on robust soliton distribution and suboptimal LT code. The validity and efficiency of data transmission in wireless relay networks could be ensured using the proposed method. References | Related Articles | Metrics

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Analysis and Comparison of Ant Colony Algorithms for Service Selection ZHANG Changsheng， REN Mingkang， YIN Hao， ZHANG Bin 2013, 34 (4):  500-504.  DOI: - Abstract ( 667 )   HTML   PDF (725KB) ( 1083 )   An ant colony optimization model for service selection was proposed on the basis of the summation analysis of the existing ant colony algorithms. The phoneme and heuristic information related with service selection were defined， and the six ant colony algorithms were applied to solve it. These algorithms were experimentally analyzed for different aspects and compared with the recently proposed service selection algorithm. The results showed that the performances of these algorithms were different and the ACS algorithm had better performance than the other compared algorithms. References | Related Articles | Metrics

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Fuzzy Spatiotemporal Data Queries Based on XQuery Symbolic Notation BAI Luyi， YAN Li， MA Zongmin 2013, 34 (4):  505-508.  DOI: - Abstract ( 677 )   HTML   PDF (419KB) ( 802 )   The conception of fuzzy spatiotemporal data queries was discussed. Fuzzy temporal queries， spatial queries， attribute queries， and spatiotemporal queries of fuzzy spatiotemporal data were studied. A symbolic notation for fuzzy spatiotemporal data queries was proposed on the basis of XQuery. The typical queries were shown by examples and explanations. In addition， the fuzzy spatiotemporal extensions of XQuery were discussed， including extensions of representation， extensions of management， and extensions of architecture. Queries in STQL and FTL could be represented using the proposed symbolic notation. What’s more， semantic confusion caused by different forms of spatiotemporal query representation could be eliminated， and a uniform representation of various types of queries on fuzzy spatiotemporal data could be obtained. References | Related Articles | Metrics

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Analysis of Scientific Collaboration Network on Internet Technology GUAN Shijie， ZHAO Hai 2013, 34 (4):  509-511.  DOI: - Abstract ( 734 )   HTML   PDF (636KB) ( 945 )   Firstly， all the authors of articles about Internet technology classification in CNKI were complied， and a scientific collaboration network was established. The basic characteristics of the network were also analyzed by statistical methods. Then， empirical analysis was made by using the complex theory， and the results showed that this complex network has a nonconnected network characteristic of scalefree. At last， the characteristics of the network among five major internal connected networks were calculated， such as convergence factor， diameter and so on. It was found out that the characteristic of smallworld was presented. The results were useful in getting information on science and technology， agglomerating new thoughts and sharing research resources. References | Related Articles | Metrics

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Related Cluster Based Trust Model for P2P Networks MA Yi， TAN Zhenhua， CHANG Guiran， WANG Xueyi 2013, 34 (4):  512-515.  DOI: - Abstract ( 584 )   HTML   PDF (522KB) ( 697 )   The characteristics of P2P networks are open， anonymous， and loosely coupled internode， which lead to false resources， malicious evaluation， and syndicates， etc. To solve this problem， a related cluster based trust model for P2P networks named RCTrust was presented. Nodes were gathered in clusters according to their interest similarity and communication history. Trust relation was categorized into two kinds according to the cluster which communication target was belonging to and subsequently each solution for these kinds was also put forward. In RCTrust， measure of node communication success rate， communications history similarity， honesty and timeliness of evaluation were used as reference parameters to evaluate the credit of peers. Simulation results showed that robustness against malicious attacks was obtained and a high rate of successful communication was provided by the proposed model. References | Related Articles | Metrics

Materials & Metallurgy

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Performances of BurningFree Aluminium BorateSiC Refractory RU Hongqiang， ZHAO Baoyu， LI Lei， LONG Haibo 2013, 34 (4):  516-519.  DOI: - Abstract ( 706 )   HTML   PDF (809KB) ( 934 )   Using silicon carbides as the main raw materials， and the phenolic resin， Al2O3 and B2O3 powders as the room temperature and high temperature bonding agents， respectively， the influences of synthetic conditions on the bulk density， flexural strength and thermal shock resistance of the burningfree aluminum boratesilicon carbide refractory materials were studied. The results showed when the mass fraction of phenolic resin was 5%， the bulk density and flexural strengths of the refractory were 266g·cm-3 and 13~21MPa， respectively. After sintering at 960℃， the main phases were SiC， Al2O3， Al4B2O9. When the mass fraction of the hightemperature binders was 75%， the bulk density had the maximum value of 255g·cm-3. When the mass fraction of the hightemperature binding agent was 125%， the flexural strength had the maximum value of 19MPa. After 5 times high temperature thermal shocks， when the mass fraction of the hightemperature bonding agent was 75%， the thermal shock resistance of the refractory was better and the flexural strength loss rate was 25%. References | Related Articles | Metrics

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Microstructure and Mechanical Properties of LowCarbon Martensite Steel Under Different Processes LI Ying， CUI Shaogang， MA Beiyue， LIU Yandong 2013, 34 (4):  520-523.  DOI: - Abstract ( 864 )   HTML   PDF (1494KB) ( 1320 )   The effects of the quenching temperature and holding time on the microstructure， tensile strength and yield strength of the lowcarbon martensite steel were investigated. The research results showed that the quenching temperature and holding time had an obvious influence on the microstructure and mechanical properties of the samples. The microstructures of the samples quenched at 890℃ for 70s and 210s mainly consisted of lath martensite and massive ferrite. The whole lath martensite microstructure was observed while quenched at 920℃ and 950℃ holding for 210s. The sample quenched at 920℃ holding for 70~210s had good mechanical properties. References | Related Articles | Metrics

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Effects of UFC Final Cooling Temperature on Microstructure and Mechanical Properties of Bridge Steels CHEN Jun， TANG Shuai， LIU Zhenyu， WANG Guodong 2013, 34 (4):  524-527.  DOI: - Abstract ( 769 )   HTML   PDF (1178KB) ( 896 )   The testing steel was cooled using ultra fast cooling (UFC) after two stage hot rolling， and the effects of UFC final cooling temperatures on the microstructure and mechanical properties of the high strength bridge steel were investigated. The results showed that the microstructural characteristics of the testing steel were obviously affected by the UFC final cooling temperatures. The main part of the microstructure of the testing steel changed from the granular bainite to the lath bainite gradually and the M/A size was significantly refined with the decrease of UFC final cooling temperatures. The effects of UFC final cooling temperatures on mechanical properties of the testing steels was also revealed. For the UFC final cooling temperature of 236℃， the yield strength， tensile strength， yield ratio， impact energy with the testing temperature of -40℃ and elongation were 745MPa， 961MPa， 078， 1665J and 168%， respectively. The balance of strength， toughness and plasticity was achieved and lower yield ratio was also gained. References | Related Articles | Metrics

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Optimization Algorithm of Spring Equation in Tandem Hot Rolling Based on Static Errors PENG Wen， ZHANG Dianhua， CAO Jianzhao， LIU Ziying 2013, 34 (4):  528-531.  DOI: - Abstract ( 628 )   HTML   PDF (577KB) ( 1088 )   In the hot strip steel continuous rolling process， when rolling suspended or roll changed， the thickness of the following strip steel was out of the precise control level which affected the yield of the strip. To solve the problem， the roll wear model and thermal expansion model were proposed， and the steady state error was put into the models to improve the spring equation. Practical application results showed that the first piece strip steel of the thickness deviation within 40μm range after changing rolls was up to 90%， and the thickness accuracy reached within 30μm under different rolling intervals， which met the requirement of the automatic gauge control system and improve the product yield. The generic solution of the steady state error in the spring equation was provided. The proposed model was online used properly for a long time， and it was suitable for the industrial production. References | Related Articles | Metrics

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Optimization of AGC System for Hot Strip Mills JI Yafeng， ZHANG Dianhua， SUN Jie， LI Xu 2013, 34 (4):  532-535.  DOI: - Abstract ( 725 )   HTML   PDF (613KB) ( 1349 )   Aiming at the problem that the accurate rack rolled thickness was not available from the spring equation in the traditional automatic gauge control AGC system which was limited by the accuracy of mill stiffness coefficient and the linear conditions of the spring curve， a method based on the mill stretch characteristic curve was proposed to calculate the strip thickness， and then the new feed forward AGC， gaugemeter AGC and the correlation models between the gaugemeter AGC and monitor AGC were put forward. The optimized AGC system was applied successfully in a hot strip mill， and the practical application showed that the thickness of the strip steels with the specification of 35mm was controlled within the allowable thickness deviation of ±20μm， and the thickness precision validation rate reached over 962%， which satisfied the requirement of production site control. References | Related Articles | Metrics

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Effects of Preoxidation on Phase Composition and Microstructure of Vanadium TitanoMagnetite CHEN Shuangyin， CHU Mansheng， TANG Jue， WU Xianglong 2013, 34 (4):  536-540.  DOI: - Abstract ( 721 )   HTML   PDF (1843KB) ( 908 )   Oxidized pellets were prepared with vanadium titaniummagnetite ores. The effects of preoxidation temperature from room temperature to 500， 700， 900， 1000， 1100， 1200， 1250℃ on phase composition and microstructure of the pellets were studied using XRD and SEM. When the preoxidation temperature was under 500℃， the transformation of γFe2O3 to αFe2O3 occurred within the pellets without oxidizing reaction. While the preoxidation temperature was above 500℃， with the increase of the temperature， TTM and FeTiO3 within the pellets were oxidized and formed TTH and Fe2TiO5， the white phase (consisting of Fe， V， Ti) gathered and gradually separated from the black phase(consisting of Mg， Al， Si)， and the crystal form transformed from relatively dispersive particles to a form with close interconnection and strong structure force. References | Related Articles | Metrics

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Effect of Calcinated Magnesite on Burst Temperature of Green Pellet GAO Qiangjian， WEI Guo， JIANG Xin， SHEN Fengman 2013, 34 (4):  542-544.  DOI: - Abstract ( 536 )   HTML   PDF (672KB) ( 991 )   The powder of calcinated magnesite was obtained by calcinating(850℃) and grinding process. The power was utilized as a binding additive to produce green pellets. The effect of the calcinated magnesite on the burst temperature of the green pellets was investigated. The results showed that the burst temperature of the green pellets increased gradually with the increase of the mass fraction of the calcinated magnesite in the green pellets. When the mass fraction of the calcinated magnesite increased from 0% to 20%， the largest increase of the burst temperature was up to 200℃. The main reasons were as follows:with the addition of the binding additive (calcinated magnesite)， the speed of waterevaporation within the green pellets decreased which led the vapor pressure of inside the green pellets to be relatively small， and the strength of the green pellets increased rapidly in the drying process， which lead the burst temperature of the green pellets increased gradually. References | Related Articles | Metrics

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Preparation of Oxidized Pellets with High Chromium VanadiumTitanium Magnetite TANG Jue， ZHANG Yong， CHU Mansheng， XUE Xiangxin 2013, 34 (4):  545-549.  DOI: - Abstract ( 786 )   HTML   PDF (1398KB) ( 1240 )   The effects of the high chromium vanadiumtitanium magnetite ores on the oxidized pellet preparation process and metallurgy properties were investigated and its largest mass fraction for superior quality of the oxidized pellets was also explored according to the research on fundamental characteristics of the ores. The results showed that the high chromium vanadiumtitanium magnetite mainly composed of magnetite， magnesioferrite， chromite， geikielite， coulsonite and titanomagnetite etc.， of which the particle size was large， and crystal stock strength was low. With the increase of the mass fraction of high chromium vanadiumtitanium magnetite in the raw materials of the pellets， the properties of green pellets had no significant changes， but the compressive strength of the finished oxidized pellets decreased， when the mass fraction of the ores was greater than 20%， the compressive strength couldn’t meet the requirement of the blast furnace production. On the other hand， increasing the mass fraction of high chromium vanadiumtitanium magnetite was conducive to reduce the reduction swelling rate of the pellets. When its mass fraction increased from 0 to 20%， the reduction swelling rate decreased from 321% to 211% accordingly. References | Related Articles | Metrics

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Effect of Lime on Digestion of Gibbsitic Bauxites at Low Temperature PAN Xiaolin， YU Haiyan， TU Ganfeng， BI Shiwen 2013, 34 (4):  551-555.  DOI: - Abstract ( 876 )   HTML   PDF (684KB) ( 2424 )   The effects and function mechanism of the different amount of lime additions on the digestion properties of three kinds of gibbsitic bauxites obtained from abroad were investigated at 145℃. All the gibbsitic bauxites are comprised of gibbsite， aluminogoethite， hematite， kaolin， quartz as well as minor anatase and boehmite characterized by XRD. The results showed that the lime addition promoted the desilication reactions， which decreased the concentrations of alumina and silica of digested sodium aluminate liquor. The corresponding silica index increased gradually and the alumina digestion rates of gibbsitic bauxites decreased linearly with the increase of the mass fraction of the lime. The conversion of desilication products from sodium silicon aluminum hydrate to hydrogarnet was also promoted by the addition of lime. The concentration of caustic alkali increased and the mass fraction of the alkali in the red mud decreased gradually with the increase of the mass fraction of the lime. References | Related Articles | Metrics

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Treatment of HighAluminium Content Iron Ore by GasBased Prereduction ZHANG Zuoliang， LI Qiang， LI Mingming， ZOU Zongshu 2013, 34 (4):  556-559.  DOI: - Abstract ( 610 )   HTML   PDF (703KB) ( 509 )   An approach of gasbased prereduction was introduced to treat a highaluminium content iron ore with total iron of 3082% (mass fraction) and Al2O3 of 2332% for AlFe separation. The results showed that the maximum reduction rate of 1# pellets reached 7713% by reduction for 77 minutes in the reduction atmosphere of 70%CO and 30%H2 in volume fraction at 900℃. The maximum reduction rate of 2# pellets reached 822% by reduction for 80 minutes with 70%CO and 30%H2 in volume fraction at 950℃. The maximum reduction rates achieved for 2# pellets at the temperatures above 900℃ were very close， so the optimal prereduction temperature of two kinds of pellets was 900℃ by taking all the factors into consideration. The additive of slaked lime undermined the existential relationship among ferreous， aluminiferous and silaceous minerals. Xray diffraction results indicated that the phases Fe2SiO4 and FeAl2O4 which were difficult to deoxidize appeared in the process of reduction and made the reduction process difficult to carry on. References | Related Articles | Metrics

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Technological Mineralogy of Copper Anode Slime LI Xuejiao， YANG Hongying， TONG Linlin， CHEN Guobao 2013, 34 (4):  560-563.  DOI: - Abstract ( 681 )   HTML   PDF (1050KB) ( 2617 )   In order to improve the technology of extracting noble metals from the copper anode slime， the technological mineralogy investigation of the anode slime was studied by XRD， SEM and optical microscope. The results showed that the particle size in the anode slime which was less than 38μm accounted for 7853%， the particle size ranged from 38 to 45μm accounted for 935%， and that of more than 45μm accounted for 1212%. The main elements were Ni， Cu， Se， Ag， Au. The main phases were gold and its alloys， silver and its compounds， copper and its compounds， nickel oxide， barium sulfate， and pyrite etc.. The gold and silver were major noble metals， individual small particles of gold was aurum lead alloy， and silver existed in forms of silver selenide and eukairite. Copper and nickel were major base metals， copper existed in native copper， copper sulphate， copper selenide and eukairite. Nickel was mainly nickel oxide. The anode slime of the copper was formed with copper sulphate as the matrix， and the native copper often coated with the nickel oxide. References | Related Articles | Metrics

Mechanical Engineering

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Dynamic Characteristics of MisalignmentRubbing Coupling Fault for Rotor System LIU Yang， TAI Xingyu， ZHAO Qian， WEN Bangchun 2013, 34 (4):  564-568.  DOI: - Abstract ( 647 )   HTML   PDF (896KB) ( 1260 )   For the misalignmentrubbing coupling fault rotorbearing system caused by misaligned bearing， mechanical and finite element models of dualdisk misalignmentrubbing coupling fault rotorbearing system were established. The equivalent misalignment moment and contact theory were used to study the effect of rotational speed on the dynamics characteristics with the nonlinear finite element method. The results showed that the misalignmentrubbing coupling fault mainly embodied in the rubbing fault， and the frequencydoubled appeared early with the peak increased rapidly. The fault signal was further divided to same width parts with the wavelet basis function， and the change trend of the double frequency peak showed that the double frequency ratio value is a judgment basis for the fault degree of the rotor system containing misalignment fault. References | Related Articles | Metrics

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Mistuned Blade Sorting Based on Improved DPSO Algorithm for AeroEngine LI Yan， YUAN Huiqun， LIANG Mingxuan 2013, 34 (4):  569-572.  DOI: - Abstract ( 593 )   HTML   PDF (703KB) ( 876 )   A dynamic model of bladeddisk system was established with mistuning parameters obtained by the modal experiment， and a new sorting method was proposed. The crossover operator， mutation operator and genetic selection of the genetic algorithm were introduced into the standard particle swarm algorithm and the penalty function was taken to balance the application requirements of the mistuning and vibration reduction. In this way the excellent characteristic of faster convergence of the particle swarm algorithm was retained， the particle swarm global optimizing ability was improved， and the ranking result accuracy was higher than that of other optimization algorithms. The results showed that appropriate blade arrangement sequence could effectively reduce the vibration localization of the bladeddisk system， and the proposed discrete genetic particle swarm algorithm could make vibration amplitude smaller or within the acceptable range of the bladeddisk system. References | Related Articles | Metrics

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Poroelastic Characteristics of Intervertebral Disc Under Intermittent Load LI Rui， GUO Lixin 2013, 34 (4):  573-577.  DOI: - Abstract ( 639 )   HTML   PDF (1118KB) ( 949 )   A poroelastic finite element model was developed to analyze the biomechanical characteristics of the human spine L4/L5 segment under continuous/intermittent loads， and the results were compared with those of a degenerated model under the same working conditions. The results showed that with the existence of the resting time， the deformation and the effective stress of the intervertebral disc decreased， while the pore pressure increased. Moreover， due to the increased stiffness and the decreased height and initial pore ratio of the degenerated disc， the changing rate of the pore pressure and the effective stress are faster than those of the healthy disc. References | Related Articles | Metrics

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Stochastic Vibration Model and Simulation of Gear Transmission System WANG Jingyue， GUO Lixin， ZHANG Liang， WANG Haotian 2013, 34 (4):  578-582.  DOI: - Abstract ( 692 )   HTML   PDF (936KB) ( 755 )   Considering the gear backlash， timevarying mesh stiffness， gear comprehensive error and bearing longitudinal response， as well as a lowfrequency external excitation caused by the torque fluctuation and the random disturbances of damping ratio， gear backlash， excitation frequency and meshing stiffness， a dynamic equation for a single pair of three degrees of freedom spur gear system was established according to Newton’s laws. Using the bifurcation diagram， phase diagram， time history chart， Poincaré map， Lyapunov exponents and power spectrum of the system， the dynamic characteristics of the gear transmission system under the change of timevarying meshing stiffness were analyzed， as well as the effect of the meshing stiffness random disturbance on the system dynamics. Numerical simulation results showed that the gear transmission system will transform from the period motion to chaos motion by doubling bifurcation with increasing the timevarying meshing stiffness. When the meshing stiffness random disturbance is not big， the periodic structure of the system solution won’t change much. References | Related Articles | Metrics

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Energy Management Strategy for Series Hybrid Electric Vehicle ZHAO Guangyao， CHEN Zeyu， DU Zhiyuan， CHEN Weiqiang 2013, 34 (4):  583-587.  DOI: - Abstract ( 993 )   HTML   PDF (901KB) ( 2142 )   Energy management strategy was researched for the series hybrid electric vehicle using system modelingstrategy developmentsimulation verification method， and models of the pivotal components of the powertrain system were built. Taking the power splitting coefficient as the control variable， an energy management strategy based on logic threshold and fuzzy algorithm was proposed for improving fuel economy. The US06 drive cycle was simulated in MATLAB/Simulink circumstance. The results showed that the proposed strategy is correct and effective for realizing better fuel economy. Fuel consumption can be reduced by 113% comparing with that of the traditional onoff strategy. References | Related Articles | Metrics

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Manufacture and Experiment of Super HighSpeed Nanovitrified Bond CBN Grinding Wheel ZHANG Jingqiang， WANG Wanshan， YU Tianbiao 2013, 34 (4):  588-593.  DOI: - Abstract ( 746 )   HTML   PDF (1337KB) ( 1239 )   The nanocomposite technology was applied to the experimental research of super highspeed vitrified bond CBN grinding wheel， and the nanovitrified bond with markedly improved mechanical and thermal properties was developed. Compared with traditional grinding wheel vitrified bond， the nanovitrified bond， possessing the strength of wheel section samples of about 8823MPa and refractoriness of 795℃， has significant advantages in the refractoriness， thermal expansion coefficient， invasion and bending strength. This super highspeed nanovitrified bonded grinding wheel also showed excellent performance in the experiments of grinding several hardtogrind materials such as stainless steel， titanium and highspeed steel. References | Related Articles | Metrics

Resources & Civil Engineering

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Ecological Cost of Mining GU Xiaowei， XU Xiaochuan， WANG Qing， WANG Run 2013, 34 (4):  594-598.  DOI: - Abstract ( 668 )   HTML   PDF (542KB) ( 1108 )   Based on the ecological footprint method， a mathematical model was built to calculate the mine ecological cost. The model was applied in an open pit mine and an underground mine to estimate their ecological costs during the production period from 2011 to 2020. The results showed that the direct economic value loss and the ecological cost of the energy consumption have a large proportion in the total ecological cost of the mine. The ecological cost of the openpit mine is about twice as much as that of the underground mine， which is mainly due to the higher reclamation cost and the loss of the direct economic value. Mine ecological cost studies and cost accounting can help mine operators in exercising better ecological cost control and fulfilling their social responsibilities， which making the mine enterprise’s own development consistent with the sustainable development of the whole society. References | Related Articles | Metrics

Management Science

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SelectionDecision of Multifinancialproduction of SmallMedium Real Estate Enterprises SONG Baoquan， YUAN Ying 2013, 34 (4):  598-601.  DOI: - Abstract ( 481 )   HTML   PDF (541KB) ( 700 )   Under the background that folk capital provides more financing product for real estate enterprises， according to the costservice matched principle， a selectiondecision model was established for the following decision goals including the lowest comprehensive financial cost and relative high social satisfaction. At the same time， the heuristic algorithm which was suitable for the selectiondecision model was got. The simulation examples showed that the proposed model and algorithm could effectively solve issues faced by smallmedium real estate enterprises in relation to the multichannel financing choices caused by multiple product decision problems. References | Related Articles | Metrics

Mathematics · Physics

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Some Notes on Fixed Point Theorems of AltmanType ZHANG Guowei， ZHANG Xiuping 2013, 34 (4):  602-604.  DOI: - Abstract ( 538 )   HTML   PDF (485KB) ( 594 )   Fixed point theorems of Altmantype were studied. The existence of the fixed point of completely continuous operator was discussed under the norm inequality conditions that the first exponent parameter was respectively greater than 1 and between 0 and 1， at the same time， the second one was not less than 0. Some new fixed point theorems were proved. These inequality conditions were different from those as shown in earlier works in which the results were extended and supplemented. The conclusions were valid for more general operators such as semiclosed 1setcontraction， convexpower condensing operator and semiclosed convexpower 1setcontraction in references. References | Related Articles | Metrics

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Holographic Quintessence Model in Nonflat Universe ZHANG Jingfei 2013, 34 (4):  605-608.  DOI: - Abstract ( 730 )   HTML   PDF (531KB) ( 1580 )   A holographic quintessence model in a nonflat universe was put forward to describe effectively the cosmological evolution of the holographic dark energy， in which a quintessence scalar field was reconstructed. The evolution equations of the holographic dark energy in a nonflat universe were derived， and furthermore the holographic quintessence model was reconstructed via the establishment of the correspondence with the canonical scalar field. Finally， the impacts of the spatial curvature on the model were discussed. The results showed that the main effect of the spatial curvature on the scalar field evolution was in the high redshift regions， and for the reconstructed potential of the scalar field， the smaller value of the field was， the more impact the spatial curvature existed. References | Related Articles | Metrics