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15 January 2014, Volume 35 Issue 1 Previous Issue    Next Issue
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Information & Control

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Method on Staffing of Call Center with Delay Information YU Miao， GONG Jun， TANG Jiafu， ZHU Huabo 2014, 35 (1):  1-4.  DOI: 10.12068/j.issn.1005-3026.2014.01.001 Abstract ( 756 )   HTML   PDF (388KB) ( 700 )   Due to the problem of staffing in a call center with delay information， an optimized M/M/N+M queue algorithm with the performance measures of the customers’ behavior was proposed. Firstly， the estimation method of waiting time of delay information announced in the system was given， then the probability of customers’ behavior of abandonment including balking and reneging was formulated as a function of delay information. Secondly， some related performances were derived by applying the birthdeath process for steady state probability， and the fixed point algorithm was designed for the optimal staffing level. Lastly， the numerical study showed how delay information impacted on customer behavior and staffing. The numerical results indicated that the method proposed is of importance to human resource management. References | Related Articles | Metrics

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Integrated Modeling Based on Mechanism and Subspace Identification for Gas Mixing Process YUAN Yan， CAO Yuan， CAO Weihua， MA Xiu 2014, 35 (1):  5-9.  DOI: 10.12068/j.issn.1005-3026.2014.01.002 Abstract ( 628 )   HTML   PDF (882KB) ( 621 )   According to the characteristics of the gas mixing process， an integrated model was set up based on mechanism and subspace identification. Firstly， on the basis of analyzing the practical operation and data， the mechanism models of the gas flow of blast furnace and coke oven were acquired by applying butterfly valve flow formula. Then datadriven subspace identification method was used to set up the 4input and 1output mixing gas pressure model. The output was the pressure of the mixed gas， and the inputs were the two gas source pressures and two valves opening of No2 in the blast furnace and the code oven. At last， through analyzing the characteristics of the variables of each submodel， the two models were integrated. The simulation results showed that the model could reflect the dynamic behavior of gas mixing process， and provided reliable model for gas mixing process control. References | Related Articles | Metrics

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Load Controllable Virtual Network Embedding Algorithm Based on Discrete Particle Swarm Optimization YUAN Ying， WANG Cuirong， WANG Cong， SHI Wenbo 2014, 35 (1):  10-13.  DOI: 10.12068/j.issn.1005-3026.2014.01.003 Abstract ( 750 )   HTML   PDF (906KB) ( 638 )   According to the multirental pattern over virtual network embedding problem in cloud computing， a resource allocation algorithm named MLBVNESDPSO was proposed to reduce the substrate link load， speed up the mapping efficiency and increase the substrate physical resource utilization. The leveraging discrete binary particle swarm optimization algorithm was combined with the virtual network embedding rules in the proposed algorithm. Both CPU and host resources utilization ratio was taken into account， so the physical link bandwidth resource was saved and the time for virtual link mapping process was reduced. The major characteristic of the mapping algorithm was that repeatable mapping for each virtual network could be supported and the load of substrate node could be controlled. Simulation results showed that in the premise of guaranteeing substrate network load the algorithm can achieve better utilization ratio of substrate network and higher revenuecost ratio of virtual networks. References | Related Articles | Metrics

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An Improved ThreeLevel Direct Torque Control Method of Brushless DoublyFed Machine LIU Yan， WANG Xu， XING Yan， YANG Dan 2014, 35 (1):  15-19.  DOI: 10.12068/j.issn.1005-3026.2014.01.004 Abstract ( 664 )   HTML   PDF (787KB) ( 576 )   To solve the problem of high amplitude ripples of stator flux linkage and torque in the traditional threelevel direct torque control(DTC) algorithm for brushless doublefed machine(BDFM)， an improved threelevel direct torque algorithm for brushless doublyfed machines based on fixed synthesizing vectors was presented. The selectivity of voltage vector was added in order to deduce the torque ripple and the flux linkage ripple. A simulation model of threelevel DTC algorithm for BDFM was established in Matlab/Simulink software environment and the effectiveness of the proposed control algorithm was testified in this model. The simulation results show that the torque ripples and the flux linkage ripples were effectively reduced， the locus of the stator flux linkage was better and the rotor speed was more stable by this improved control method. In addition， the advantage of fast torque response in the DTC algorithm was maintained. The dynamic performance and robustness was improved in this DTC system. References | Related Articles | Metrics

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A Novel Image Encryption Scheme with 2DLogistic Map and Quadratic Residue ZHU Hegui， LU Xiaojun， ZHANG Xiangde， TANG Qingsong 2014, 35 (1):  20-23.  DOI: 10.12068/j.issn.1005-3026.2014.01.005 Abstract ( 887 )   HTML   PDF (2429KB) ( 838 )   Considering the importance of image transmission in the public net， a new image encryption algorithm was proposed based on the 2DLogistic chaos and quadratic residue. Firstly， the original image was shuffled twice with the 2DLogistic chaos map， and the positions of the original image were changed sufficiently. Then， the shuffled image was turned into a binary sequence， and every 8 bits were called a block. For each block， quadratic residue was applied to encrypt the block， then， the encrypted binary sequence was turned into the encrypted image. Therefore， the statistical information of plain image was changed drastically by the proposed scheme. The proposed image scheme was tested by various types of experiment and security analyses such as histogram analysis， information entropy， key sensitivity and correlation coefficient analysis. All these analyses demonstrated that the proposed scheme can resist statistical attack， information entropy attack， and it is very proper for secure image communication. References | Related Articles | Metrics

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Total Variation Regularized SENSE MRI Reconstruction Based on Fast Split Bregman Iteration WU Chunli， ZHU Xuehuan， ZHAI Jiangnan， DING Shan 2014, 35 (1):  24-28.  DOI: 10.12068/j.issn.1005-3026.2014.01.006 Abstract ( 792 )   HTML   PDF (459KB) ( 922 )   In parallel magnetic resonance imaging (MRI)， the signal to noise ratio (SNR) of reconstruction image would be obviously reduced under the high acceleration factors because of the illposed problem in the process of sensitivity encoding (SENSE) reconstruction. Through indepth analysis of total variation (TV) regularized SENSE reconstruction model， an efficient and fast split Bregman iteration algorithm was introduced to obtain the optimal solution and effectively improve the image reconstruction results. The simulation experiments were carried on the phantom data and brain data of MRI， respectively. The experimental results demonstrated that compared with the traditional TV regularized SENSE reconstruction algorithm， the proposed algorithm not only has fewer iterations and faster convergence speed， but also can alleviate the aliasing artifacts， significantly improves the SNR and decreases the normalized mean squared error of reconstruction image. References | Related Articles | Metrics

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An Artificial Bee Colony Algorithm for Solving SAT Problem GUO Ying， ZHANG Changsheng， ZHANG Bin 2014, 35 (1):  29-32.  DOI: 10.12068/j.issn.1005-3026.2014.01.007 Abstract ( 809 )   HTML   PDF (373KB) ( 715 )   For SAT problem， a discrete artificial bee colony algorithm named ABCSAT algorithm was proposed. The corresponding optimization model was established， and the key issues such as problem encoding and transition， fitness function， bee’s foraging strategy， discrete operation etc. were solved. Different from dealing with continual optimization problem， fitness function was defined as the number of unsatisfied clauses in the ABCSAT algorithm. According the character of SAT problem， series of foraging strategy were designed and discrete operations on candidate solutions were performed by using the heuristic information of constraint relations among each clause and variable. Through experiments on the standard SATLIB benchmarks， the algorithm was tested and compared with related algorithms. The results validated the effectiveness of ABCSAT algorithm on middle/smallscale SAT problems， and showed that the algorithm could be more effectively on solving this problem. References | Related Articles | Metrics

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Improvement of Blood Pressure Measurement Based on ECG and PPG XU Jiuqiang， LIN Hongji， LI Han， ZHAO Hai 2014, 35 (1):  33-37.  DOI: 10.12068/j.issn.1005-3026.2014.01.008 Abstract ( 1383 )   HTML   PDF (970KB) ( 4751 )   According to feature point detection algorithm with large computation of blood pressure measurement based on ECG and PPG， a feature point detection algorithm was proposed based on an improved difference method. The efficiency of the improved algorithm and the accuracy of the feature point detection had been largely improved. Through correlation analysis and regression analysis of the sampling data， the SBP(systolic blood pressure) had a strong correlation with PWTT(pulse wave transmit time)， but DBP(diastolic blood pressure) had a moderate correlation with PWTT. The experimental results indicated that using the improved algorithm， the PWTT could be calculated accurately， and then the SBP could be obtained. Also the deviation requirement could be met to noninvasive blood pressure measurement of AAMI. References | Related Articles | Metrics

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Research on the Bottleneck Delay of Internet IPLevel Topology ZHAO Hai， YAO Chengcheng， AI Jun， JIA Siyuan 2014, 35 (1):  38-41.  DOI: 10.12068/j.issn.1005-3026.2014.01.009 Abstract ( 634 )   HTML   PDF (1065KB) ( 675 )   With IP level data collected from CAIDA， the characteristic of bottleneck in Internet was analyzed. Firstly， a statistical analysis about critical delay of network paths was made， which indicated that the bottleneck delay appeared in more than 80% network paths. And then a quantitative analysis on the bottleneck delay showed that the bottleneck made the similar network diameter’s network delay distinct. Furthermore， an analysis on IP addresses of the network delay and bottleneck delay from the degree of the geography location was performed， and it could be concluded that there was a big difference between network delay and bottleneck delay. Finally， a research on the causing of the bottleneck was made， which indicated that propagation delay was the main factor of the bottleneck delay for long distance， whereas the queue delay was the main factor for a short range. References | Related Articles | Metrics

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Analysis of Fractal Characteristic of Internet Router and IPv6 Level Topology MI Xue， ZHU Jian， ZHAO Hai 2014, 35 (1):  43-46.  DOI: 10.12068/j.issn.1005-3026.2014.01.010 Abstract ( 667 )   HTML   PDF (768KB) ( 562 )   A guidance and basis can be provided for Internet’s redesign and performance improvement by analyzing the Internet’s structural characteristics. Firstly， variation characteristics of network parameter could be got by using coarsness renormalization to process IPv4 level and IPv6 level’s topology in Internet. Secondly， fractal feature of degree’s distribution in Internet was explored. Finally， the fractal feature of IP level data in time evolution dimensionality was researched by analyzing the data from CAIDA data source. The result showed that， the network was of fractal similar feature while the value of the network’s k was low， and the connections among nodes with high degree went down as the development of time dimension. The relevant conclusions could be used to guide the subsequent research in Internet’s structural characteristics. References | Related Articles | Metrics

Materials & Metallurgy

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Influence of P on Volume Fraction and Morphology of Ferrite Under Subrapid Solidification QIU Yiqing， LIU Zhenyu， LI Na， WANG Guodong 2014, 35 (1):  47-50.  DOI: 10.12068/j.issn.1005-3026.2014.01.011 Abstract ( 516 )   HTML   PDF (1578KB) ( 600 )   The ferrite in twinroll cast strips with different P contents was analyzed by the observation of the microstructure. The results showed that the volume fraction of ferrite in the cast strip was obviously more than that in the cast billet with the same P content. In a cast strip， the volume fraction of ferrite in the surface layer was less than that in the center area， and the ferrite in the surface layer was reduced with the reduction of the P content. The morpology of the ferrite in the cast strip was gradually transformed from the acicular form into the polygonal form with smooth surface with the increase of the P content. Through the theoretical analysis， it was shown that the rapid cooling favored ferrite stabilizing in steels， and the polygonal ferrite with smooth surface directly precipitated from the liquid steel while the acicular ferrite precipitated from the solid austenite. References | Related Articles | Metrics

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Analysis of Working Temperature of Coil Used in Electromagnetic Induction Controlled Automatic SteelTeeming System LIU Xingan， WANG Qing， LIU Tie， HE Jicheng 2014, 35 (1):  51-54.  DOI: 10.12068/j.issn.1005-3026.2014.01.012 Abstract ( 643 )   HTML   PDF (1019KB) ( 678 )   In order to apply the electromagnetic induction controlled automatic steelteeming system in production， a new insulating method which can ensure the normal operation of the induction coil used in the system in hightemperature nozzle brick was proposed. The numerical simulation method was employed to investigate the heat flux of the nozzle brick used in 300t ladle of the electromagnetic steelteeming system and the working temperature of the induction coil implanted in the high temperature nozzle brick with and without the insulating layers. The results showed that the induction coil was not suitable using in high temperature nozzle brick without the insulating layers， while the induction coil working temperature decreased with the insulating layers on the top and both sides of the induction coils. The thickness and the conductivity of the insulating layer both affected the coil working temperature. The coil working temperature decreased from 1187℃ to 467℃ at the condition of the thickness 40mm， the conductivity 003W/(m·℃) and met the coil working demands. References | Related Articles | Metrics

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Special Technique for Forming Big Inch Tapered Square Pipes XIA Hongyan， BIAN Qing， WU Di 2014, 35 (1):  56-59.  DOI: 10.12068/j.issn.1005-3026.2014.01.013 Abstract ( 763 )   HTML   PDF (620KB) ( 534 )   The special dieless drawing technique and the mathematical model of dieless drawing speed for big inch tapered square pipes were established. The key processing parameters were determined based on our systematically researching and analyzing on the deformation mechanism of dielss drawing for big inch tapered square pipes. The dieless drawing technique and equipments were simple and for the tapered square pipe dieless forming， one dieless production procedure can replace all the forming procedure in the general. It completed the deformation heat treatment simultaneously during the dieless drawing process， which enhanced the overall performance of the products. The method is suitable especially for the variable section pipes with high strength， high friction and low plasticity. The experimental study showed that ideal tapered square pipes can be drawn by the dieless drawing technique and the size precision and surface quality of products are super compared with the bend welded steel pipes. The relative errors of tapered square pipes between the model calculation results and the experiment results are less than 78%， which indicated that the dieless drawing technique is with great practical value. References | Related Articles | Metrics

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Mathematical and Physical Simulations of the New Type Feeding System in Strip Casting REN Sanbing， ZHU Miaoyong， FAN Junfei 2014, 35 (1):  60-63.  DOI: 10.12068/j.issn.1005-3026.2014.01.014 Abstract ( 543 )   HTML   PDF (584KB) ( 583 )   A 1∶1 scale water model tester of twinroll strip casting was set up based on the Froude number and Reynolds number similarity criteria in order to evaluate the new type feeding system. Fluctuation in the surface of the molten pool producing in twinroll strip casting process was studied by hydraulics simulation experiment using DJ800 system. Meanwhile the flow filed distribution inside the molten pool of the twinroll strip casting was studied by solving the continuous equation，NS equation and κε equation using CFD software. Differences of the flow field and surface fluctuation were analyzed on new and old type of the feeding system in Baosteel. The results showed that the new type feeding system had great effect for lowering the wave fluctuation and improving the surface flow filed morphologies of the molten pool. Moreover， the CFD method combined with physical modeling test was suitable for assessing the feeding system used in the strip casting. References | Related Articles | Metrics

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Experimental Study of Effects of Refractory on Oxygen Content in Molten Steel LIU Jiazhan， YU Jingkun 2014, 35 (1):  64-66.  DOI: 10.12068/j.issn.1005-3026.2014.01.015 Abstract ( 693 )   HTML   PDF (429KB) ( 682 )   The effects of MgOCr2O3， MgOAl2O3， Al2O3 and MgOC refractories on the oxygen content and inclusions of the molten steel were investigated. Based on the thermodynamic theory， the mechanism of oxygen transfer from the refractory to the molten steel was also researched. The results showed that the ability of oxygen transfer of the refractories ranks in a descending order as MgOCr2O3， MgOAl2O3， Al2O3 and MgOC refractories at 1600℃. The main reason of the oxygen transferred from the refractory to the molten steel was that the equilibrium partial pressure of O2 in closed pores of the refractory produced by the decomposition of the oxide contents was much higher than that of in the molten steel. The CO formed inside MgOC refractory decomposed at the interface and dissolved in the molten steel. References | Related Articles | Metrics

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ZrO2+MgS Auxiliary Electrode Coating Prepared by Laser Cladding MAO Feixiong， LIU Tao， YU Jingkun 2014, 35 (1):  67-69.  DOI: 10.12068/j.issn.1005-3026.2014.01.016 Abstract ( 850 )   HTML   PDF (1147KB) ( 616 )   The ZrO2+MgS auxiliary electrode coating was prepared on the surface of the MgO stabilized zirconiabased solid electrolyte by laser cladding. The surface morphology and phase composition were analyzed with the scanning electronic microscope (SEM) and Xray diffractometer (XRD). The factors influenced the stability of ZrO2+MgS coatings were also analyzed. The research results showed that the cladding layer was combined well with the substrate. MgS powder were not fully decomposed and oxidized. From this work， it showed that laser cladding was an effective method to prepare ZrO2+MgS coating on the surface of the MgO stabilized zirconiabased solid electrolyte. At 1600℃， if the sulfur partial pressure was higher than 10-495Pa， MgS phase did not decompose; if the oxygen pressure was 10-5578Pa and sulfur partial pressure was higher than 10-4636Pa， MgS phase did not oxidize. References | Related Articles | Metrics

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Rist Operating Line Model for COREX Process and Its Application Analysis ZHAN Wenlong， WU Keng， YU Yingchang， LIU Qihang 2014, 35 (1):  71-74.  DOI: 10.12068/j.issn.1005-3026.2014.01.017 Abstract ( 751 )   HTML   PDF (357KB) ( 645 )   Material balance and heat balance equations in COREX smelting reduction process were established by taking the principle of Rist operating line in blast furnace for reference. As the mainly raw materials， lump coal with high volatile would generate large amounts of H2 during the splitting decomposition in the process. Therefore， the influences of H2 on the Rist operating lines of the upper shaft furnace and the lower melter gasifier must be considered. Through the thermodynamic calculation， the mathematic model of Rist operating lines for the whole COREX process was established by an combination of the upper and the lower operating line. Several methods for decreasing the consumption of COREX fuels were proposed， such as improving melting rate， changing the charging fuel structure and so on. The calculation results showed that when the inferiority coke was used for COREX instead of lump coal， the fuel and oxygen saving reached 1747kg and 188% in theory， respectively. References | Related Articles | Metrics

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Pyrolysis Properties of Crystallization Aluminium Chloride ZHAO Aichun， ZHANG Tingan， LYU Guozhi， LIU Yan 2014, 35 (1):  75-78.  DOI: 10.12068/j.issn.1005-3026.2014.01.018 Abstract ( 844 )   HTML   PDF (905KB) ( 787 )   Performances of alumina prepared by pyrolysis aluminium chloride which was a key technology in a new acid process (the doublecycle method) were studied by the chemical analysis and Xray diffraction (XRD). The pyrolysis properties of crystalline aluminium chloride at the static atmosphere and water vapor status with different temperatures and time were mainly investigated. By comparison， the results showed that the decomposition rate in water vapor was significantly higher than that of the direct decomposition one without water vapor. Chlorine mass fraction in the product could be reduced to 014% with the optimal conditions for the pyrolysis in water vapor of a pyrolysis temperature of 800℃ and a pyrolysis time of 30 minutes. while for that in the static atmosphere， the chlorine mass fraction of 025% was obtained at a pyrolysis temperature of 900℃ for holding a pyrolysis time of 60minutes. References | Related Articles | Metrics

Mechanical Engineering

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Simulation on 3D Contact Nonlinear Dynamic Characteristic in Gearbox Coupling System LIANG Mingxuan， YUAN Huiqun， LI Yan， YU Yinxin 2014, 35 (1):  79-83.  DOI: 10.12068/j.issn.1005-3026.2014.01.019 Abstract ( 687 )   HTML   PDF (1167KB) ( 607 )   Considering the drawbacks of existing dynamics model and analysis method of gear transmission system， the dynamic analysis method based on perfectly elastic body was presented. A certain type of marine gearbox was taken as the reserch object. Based on explicit dynamic finite element method， the 3D dynamic contact nonlinear model of housingbearinghelical gear pair system was established by considering the coupling effect between components. The dynamics characteristics on the key components were obtained by dynamically simulating the system， then compared with uncoupled model. It is shown that the stress distributions both on rolling elements and teeth surface are uneven and the coupling among the parts aggravates the impact effect in the gearbox. Finally the results are verified by Hertzian line contact theory. References | Related Articles | Metrics

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Determination About Preventive Maintenance Time of the Repairable System SUN Zhili， WANG Jian， YIN Mingang， YANG Qiang 2014, 35 (1):  84-87.  DOI: 10.12068/j.issn.1005-3026.2014.01.020 Abstract ( 835 )   HTML   PDF (386KB) ( 985 )   A method was proposed to determine preventive maintenance time for repairable and maintainable systems. The life cycle was defined by building the joint density function of working time and maintenance time. Considering the profit during working time and the loss during maintenance time， the function between unit time profit expectation and preventive maintenance time T in a life cycle was confirmed by applying the theory of mathematical expectation of random variable function. The optimal objective is to maximize the unit time profit expectation. Newton’s method was used to confirm the optimal preventive maintenance time， then the corresponding reliability would be confirmed based on the optimal objective. A numerical example showed that the proposed model is valid.The distribution parameter effect on the optimum preventive maintenance time was analyzed. References | Related Articles | Metrics

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Reliable Life Prediction for Special Equipments with the Measurable Potential Failure Mode YANG Qiang， SUN Zhili， ZHAO Xin， ZHANG Lei 2014, 35 (1):  88-92.  DOI: 10.12068/j.issn.1005-3026.2014.01.021 Abstract ( 600 )   HTML   PDF (404KB) ( 615 )   The traditional reliability analysis method of huge data samples cannot be applied to life prediction of the special equipments because of lacking failure samples. Prior information of reliability estimation can be calculated according to the failure data from laboratory during designing and precious records of similar products. Then， the reliability estimation modal was built based on Bayes theorem combining prior information with small samples from field test， and the posterior distribution was obtained. Taking the main beam deflection of overhead travelling crane as one measurable potential failure mode， reliable life prediction of twocycle is realized， i. e. the work time from deflection zero to potential failures and work time from potential failures to functional failure are calculated. The research provides not only some theoretical basis for the main beam inspection and maintenance but also a reference for reliable life prediction and risk prevention of special equipments which lack failure data from factory and laboratory. References | Related Articles | Metrics

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Random Load History of Hydraulic Support and Application of Monte Carlo Method MA Yuanyuan， XIE Liyang， LIN Wenqiang 2014, 35 (1):  93-96.  DOI: 10.12068/j.issn.1005-3026.2014.01.022 Abstract ( 555 )   HTML   PDF (1120KB) ( 630 )   To accurately predict the service life of hydraulic support， the origin and characteristics of the external load of the hydraulic support were analyzed using the interaction relationship between surrounding rock and hydraulic support based on the movement of surrounding rock. Monte Carlo method is used to obtain the load spectrum. The statistics results show that the load amplitude and the load average obey Weibull distribution W(131， 21696) and normal distribution N(1200， 5196)， respectively. Then， the actual load history of hydraulic support at underground was simulated. The work prepares for further research and compiling load spectrum so as to make the life prediction and simulation test indoor. References | Related Articles | Metrics

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TimeDependent Reliability Analysis of Underground Vehicle’s Parts Based on Multicrack Propagation SHI Boqiang， TANG Geteng 2014, 35 (1):  97-100.  DOI: 10.12068/j.issn.1005-3026.2014.01.023 Abstract ( 669 )   HTML   PDF (592KB) ( 521 )   Considering the existence of multicrack damage in underground vehicle’s parts， the torsion fatigue test for simulating the fatigue damage was built. The surface crack after certain fatigue cycles was further measured by telephoto microscope and camera， and the Paris model and residual strength estimation model were used to process the data for residual intensity. Then， the timedependent reliability mathematical model was used to calculate the drift rate and fluctuation rate of timevariant intensity， and finally educed the reliability. This method solves the problem of dynamic detection of parts’ time varying intensity when using timedependent theory， and advances the timedependent theory to the engineering application. It has a good application prospect. References | Related Articles | Metrics

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Powerful Shifting Strategy and Multiparameters Considered for HeavyDuty Mining Truck ZHAO Xinxin， ZHANG Wenming， FENG Yali， YANG Yaodong 2014, 35 (1):  101-105.  DOI: 10.12068/j.issn.1005-3026.2014.01.024 Abstract ( 693 )   HTML   PDF (892KB) ( 736 )   The powerful shifting strategy considering multiparameters for mining truck was set up based on the weight， working condition and change rate of throttle angle， uphill with overload and downhill with empty load. The full field performance function of diesel engine Cummins QSLFR91674 was established by the superposition method. In addition， the relationship between engine speed and output torque in different throttle angles was shown by this function. Based on the engine dynamic performance， the powerful shifting strategy of vehicle speed， throttle angle and vehicle acceleration was designed for the mining truck named 3550. The strategy was further optimized combining the identification method for road condition， the state of vehicle load， and the driver intentions. The power train system simulation model was established in Maplesim， and simulation results represent that the optimized strategy can precaution unnecessary shift and improve the dynamic performance for vehicle. References | Related Articles | Metrics

Resources & Civil Engineering

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Comparison of the Late Carboniferous Reef Community Ecosystem in Guizhou and Guangxi YANG Dayong， GONG Enpu， CHEN Xiaohong， GUAN Changqing 2014, 35 (1):  107-111.  DOI: 10.12068/j.issn.1005-3026.2014.01.025 Abstract ( 545 )   HTML   PDF (882KB) ( 616 )   To better understand the effects of biological and environmental factors of late Carboniferous reefs on organic reef development， through the reef community ecology and environment， comparative study was done with the late Carboniferous ecological characteristics of reefbuilding communities， effect of the biological factors on reef community development， the reef development background and construction scale in Guizhou and Guangxi. The key species occupied obvious dominance， reefbuilders grew rapidly and had a strong colonial ability， and the largescale reefs， made reefs develop more maturely in Houchang， Guizhou. While in Langping， Guangxi， no obvious key and dominant species appeared， reefbuilders were not prominent in their ecological features and poor reefbuilding ability， the environmental influence of shoal was significant and smallscale reefs were the direct causes of poor development of reefs. References | Related Articles | Metrics

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Effect of Z164D Solution on Bauxite Strength and Its Mechanism WANG Zehong， WANG Huai， LI Guofeng， YU Fujia 2014, 35 (1):  112-116.  DOI: 10.12068/j.issn.1005-3026.2014.01.026 Abstract ( 698 )   HTML   PDF (670KB) ( 577 )   Using Z164D as grinding aid， the Bond work index of ball mill experiments and the uniaxial compressive strength experiments of bauxite from Tianyang Guangxi were carried out separately. The results showed that compared with raw ore， the Bond work index of bauxite soaked with water and Z164D solution are decreased by 105% and 379%， and the uniaxial compressive strength are reduced by 2684% and 4279%， respectively. The physical and chemical adsorption between Z164D and bauxite surface are confirmed through the analysis of IR spectra and energy dispersive Xray spectroscopy， and Z164D cannot dip into bauxite inners. A function mechanism model of the effect of Z164D solution on bauxite strength is built， where water and Z164D promote each other to increase defects of bauxite and lower its strength. References | Related Articles | Metrics

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Finite Element Analysis of Transient Unloading and Plastic Zone Distribution in Surrounding Rock WEI Jiong， ZHU Wancheng， NIU Leilei， WEI Chenhui 2014, 35 (1):  117-121.  DOI: 10.12068/j.issn.1005-3026.2014.01.027 Abstract ( 887 )   HTML   PDF (969KB) ( 802 )   Up to now， the tensile failure in highly stressed rock after excavation， resulted from unloading， is a common phenomenon， but not well theoretically explained yet. Taking the unloading as a dynamic process， a plasticity model for transient unloading was developed to study the failure mechanism in the surrounding rock based on the theory of continuum elastoplasticity using the finite element analysis (FEA) with a commercial software COMSOL Multiphysics. The results show that excavation can trigger strong disturbance in surrounding rock due to the transient release of insitu stress. The stress redistribution is a dynamic process transiting from dynamic stress response to quasistatic stress condition. The transient unloading can cause tensile stress near the excavation surface. Although the duration of transient tensile stress is short， its amplitude is small and the affected domain is limited， the tensile stress may result in tensile failure because the uniaxial tensile strength of rock is far lower than its compressive strength. It is also denoted that the lateral inertia effect may be one reason for this phenomenon. References | Related Articles | Metrics

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ThreeDimensional Modeling and Visualization Information Management of Geotechnical Engineering Investigation Sites GUO Jiateng， WU Lixin， YANG Yizhou， ZHOU Wenhui 2014, 35 (1):  122-125.  DOI: 10.12068/j.issn.1005-3026.2014.01.028 Abstract ( 630 )   HTML   PDF (990KB) ( 872 )   Based on several kinds of geotechnical engineering information obtained from multiple sources and different structures， such as drilling hole detection， standard penetration test， topographic surveying etc.， a series of specific methods for data preprocessing， integral modeling， 3D visualization and information management of the engineering sites were intensively inverstigated. Based on these methods， a software was developed， by which the stereo space of a geotechnical engineering site， including spatial objects such as topography， buildings， boreholes， stratum， groundwater etc.， can be integrally modeled and visualized with threedimensional models. These 3D models can facilitate functions such as attribute query， information updating and section analysis. The 3D integral modeling software was proposed as a new pattern of geotechnical engineering report beyond traditional 2D report. The software has been applied to several geotechnical projects， whose results demonstrate that the stereo space model of a geotechnical engineering site can be automatically and conveniently reconstructed. The 3D integral modeling and visualization methodology presented contribute a lot to 3D information technology development of geotechnical engineering. References | Related Articles | Metrics

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Influence of Coal Dust on the Ignition of Methane/Air Mixture by Rotating Friction Sparks LI Gang， YU Yunjiang， SHANG Rongxue， YUAN Chunmiao 2014, 35 (1):  126-130.  DOI: 10.12068/j.issn.1005-3026.2014.01.029 Abstract ( 673 )   HTML   PDF (686KB) ( 680 )   A rotating friction test device was set up based on the GB13813 to investigate the ignition regularities of methane， air and coal dust. The observation via high speed camera and infrared thermography shows that the methane/air mixture is ignited by titanium particle spark during the friction process of A3 steel and titanium bar. A set of experiments， using lignite， bituminous and anthracite with 3 kinds of particle diameters， were conducted to test the influence of coal dust on the ignition of methane/air mixture. It is found that the ignition delay time gets longer when introducing coal dust and smaller particle can cause longer delay time. The ignition delay time for the three kinds of coal from short to long is bituminous， anthracite and lignite， which accords with the water content in the sample. The delay time has nothing to do with the volatile of the coal. References | Related Articles | Metrics

Management Science

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On Measuring Users’ Emotions in Interacting with Webs GUO Fu， YU Cong， DING Yi 2014, 35 (1):  131-134.  DOI: 10.12068/j.issn.1005-3026.2014.01.030 Abstract ( 637 )   HTML   PDF (323KB) ( 1115 )   Targeted at the difficulity in measuring objectively users’ emotions in interacting with webs，a method was proposed by using eye movement data. Firstly，the PAD scale in Chinese and the initial eye movement indexes were selected，the representative webs were chosen through a questionnaire，and the interaction tasks were designed. Secondly，the users’ eye movement and PAD data were obtained through an experiment. Then the eye movement indexes related to emotions were determined after the variance homogeneity test and oneway ANOVA，placing emotional classification as the influential factor. Finally，the relational models between eye movement data and users’ emotions were constructed with the partial least square method，and the effectiveness and adaptability of the models were verified. The results indicated that the models have good performances in measuring web users’ emotions. References | Related Articles | Metrics

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Network Modeling and Empirical Study of Information Spillover Among Industries of Chinese Stock Market HUANG Weiqiang， ZHUANG Xintian， YAO Shuang 2014, 35 (1):  135-138.  DOI: 10.12068/j.issn.1005-3026.2014.01.031 Abstract ( 846 )   HTML   PDF (347KB) ( 612 )   By integrating the traditional econometrical methods with the complex network modeling and analyzing methods， the information spillover relationships among industries of Chinese stock market and the individual industry information spillover abilities as well as their distributions were empirically studied. The results indicated that the returns term does not exert any effect on the information spillover among industries. The market factors significantly strengthen the bilateral information spillover effects among industries and significantly weaken the unilateral information spillover effects among industries. The information spillover effects tend to be strengthened or weakened with the ups and downs of the market. The individual industry’s information spillover ability takes on the distribution of a higher peak and a fat tail. Furthermore， with the MST (minimal spanning tree) method， the rules of information spillover among industries can be found quickly and effectively. References | Related Articles | Metrics

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Study on the Relationship Between Investors’ Sentiment and Stock Returns JIN Xiu， ZOU Jie 2014, 35 (1):  139-142.  DOI: 10.12068/j.issn.1005-3026.2014.01.032 Abstract ( 662 )   HTML   PDF (387KB) ( 1861 )   By constructing the investors’ sentiment index and applying the linear and nonlinear Granger causality tests， the relationships between investors’ sentiment and stock returns at different market states were studied. The empirical results showed that there is a oneway linear causality relationship and a significant twoway nonlinear causality relationship in the whole sample period; therefore， the relationship between investors’ sentiment and stock returns can be understood more comprehensively by using the nonlinear causality test. The nonlinear causality relationships between them at the bull and bear market states are different， which is consistent with the reality of China’s stock market， the one filled with irrational sentiments. References | Related Articles | Metrics

Physics

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Effects of Cooling Processes on Structural Changes for an Au24Cu19 Alloy Cluster ZHAO Bingjun， ZHANG Lin 2014, 35 (1):  144-148.  DOI: 10.12068/j.issn.1005-3026.2014.01.033 Abstract ( 723 )   HTML   PDF (646KB) ( 681 )   The structural changes of a binary metal Au24Cu19 cluster containing 24 gold atoms and 19 copper atoms on quenching and continuously cooling procedure were studied by NVT moleculardynamics simulations within the framework based on the embeddedatom method. On the analysis of average potential energy per atom， pair numbers of the main atom bond， and the atom packing structure varying with the temperature， the clusters presented the configuration that the inner part was the copper atoms， coated with the gold atoms and a few of copper atoms with the decrease of the temperature. At the relative high temperature regime， the pair numbers presented highlow vibration changes during the process of quenching， whereas they presented lowhigh vibration changes during the continuously cooling process. At the relative low temperature regime until 400K， the pair numbers were changed synchronously under both cooling conditions. References | Related Articles | Metrics

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Study of AudioFrequency Internal Friction in BakeHardening Steel YU Ning， LIU Yonggang， ZHAN Hua， JI Jingwen 2014, 35 (1):  149-152.  DOI: 10.12068/j.issn.1005-3026.2014.01.034 Abstract ( 577 )   HTML   PDF (684KB) ( 555 )   The internal frictions from 290 to 630K in the H180 steel specimens hotrolled or baked for various time were measured under different conditions with and without a magnetic field (magnetic field strength is 300Oe) using an audiofrequency internal friction instrument. It is found that there are two clear peaks of internal friction in all the Q-1T curves， and that the first peak appears at about 362K， while the other one occurs at about 474K (measurement frequencies are 2300~2150Hz). With increasing baking time， the first peak continuously decreases but the second peak increases. Analysis demonstrates that the first peak is the Snoek peak and the second one is the B peak. A comparison of the internal frictions measured with and without a magnetic field shows that the background internal friction measured under a magnetic field is higher than that measured without a magnetic field. Such a background internal friction is enhanced under the present audiofrequency measurements， but it decreases with increasing the measurement temperature. References | Related Articles | Metrics