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15 February 2018, Volume 39 Issue 2 Previous Issue    Next Issue
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Information & Control

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Active Control Strategy for Upper Limb Rehabilitation Robot Based on Velocity Field FANG Xiao-ke， HAN Bing， ZHU Xue-feng， WANG Jian-hui 2018, 39 (2):  153-158.  DOI: 10.12068/j.issn.1005-3026.2018.02.001 Abstract ( 838 )   HTML   PDF (739KB) ( 1265 )   Considering the safety and stability of an upper limb rehabilitation robot and patients’ active participation in rehabilitation training stage， a contour following strategy different from trajectory tracking is applied， as well as an active controller. The contour following strategy can be implemented through confining robot’s motion by velocity fields. The velocity fields enable the robot to follow desired curves in space smoothly and stably. The velocity of robot motion can be adjusted according to the patient’s forces which are taken into account in the active controller， thus promoting the patients to participate rehabilitation training actively. Simulation results show that the contour following and active controller ensure tracking precision and realize human-robot interaction. References | Related Articles | Metrics

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Molten Steel Level Measurement Based on Optical Flow Analysis SU Zhi-qi， HE Qing， XIE Zhi 2018, 39 (2):  158-161.  DOI: 10.12068/j.issn.1005-3026.2018.02.002 Abstract ( 795 )   HTML   PDF (1212KB) ( 1274 )   In some continuous caster， slag often adheres to the temperature-measuring tube. This phenomenon disturbs the vision-based molten steel level measurement system analyzing the temperature field of the temperature-measuring tube. To solve this problem， the liquid slag adhered on the tube lifted from the molten steel was tracked via optical flow analysis and the adherent characteristic in the different position of the tube was gathered， then the relation between the adherent characteristic and the molten steel level prior to lifting was analyzed， finally the molten steel level in the tundish was calculated. Validated by other methods， the error of this method is less than 3mm. Lots of on-site experiments indicate that this method may well solve the problem of missing temperature data， and accurately measure the molten steel level in the exceptional case of temperature-measuring tube adhering with liquid slag. References | Related Articles | Metrics

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Development of a Two-Color Pyrometer with a Reflector Placed Ahead CHE Xun-jian， XIE Zhi 2018, 39 (2):  162-165.  DOI: 10.12068/j.issn.1005-3026.2018.02.003 Abstract ( 751 )   HTML   PDF (703KB) ( 1076 )   An improved two-color pyrometer for measuring surface temperature ranging from 600℃ to 1200℃ is developed. A gold-plated semispherical reflector is placed ahead of a two-color pyrometer. When the reflector is positioned facing the measured target， the received radiance energies are increased， and the disparity between the effective emissivities of the two received wavelengths is decreased. As a result， the measurement error of the two-color pyrometer is reduced，compared with the one without a reflector. The expression of effective emissivity for the focused reflector is deduced. A fast measurement apparatus is developed， which spends 0.7s on one time of measurement， in order to prevent temperature disturbance. A plain-type thermocouple is made， and the proposed pyrometer measures the surface temperature of the thermocouple for validation. The measurement error is within 1.1℃. References | Related Articles | Metrics

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Cooperative Caching Strategy Based on Cache Cost for Information-Centric Networking CAI Ling， WANG Jin-kuan， WANG Xing-wei， HAN Lai-quan 2018, 39 (2):  166-171.  DOI: 10.12068/j.issn.1005-3026.2018.02.004 Abstract ( 791 )   HTML   PDF (547KB) ( 974 )   In-network caching is one of the core issues in information-centric networking (ICN) which will directly restrict the data dissemination performance of the network. Considering the cache cost contains not only the path cost raised by accessing a cache node on the path but also the replacement cost of old information， a path and node cost based cooperative caching strategy (PNC3S) is proposed. The PNC3S considers the path cost and replacement cost comprehensively， and whether information matches a node or not depends on the total cost. Then the optimization algorithm is introduced into the proposed strategy to make caching decision. The simulation experiments demonstrate that the proposed PNC3S， compared with CEE (cache everything everywhere) and LCD (leave copy down)， improves such performance as cached information ratio， server load ratio， average link utilization ratio and hop reduction ratio. References | Related Articles | Metrics

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Audio Commercials Statistics Method Based on Overlapping Cellular Shift LIU Ji-hong， XIE Li-yan 2018, 39 (2):  172-175.  DOI: 10.12068/j.issn.1005-3026.2018.02.005 Abstract ( 562 )   HTML   PDF (584KB) ( 687 )   To meet the demand of commercials-monitoring needed by the radio stations， an algorithm of audio commercials detection is proposed based on the overlapping cellular shift (OCS). Different types of commercials are used as research objects in the algorithm because of the diversity of commercials. Based on cellular automaton theory and the characteristics of audio， audio commercials are detected by using the method of the OCS combined the cross-correlation function. The experiment results show that the OCS-based algorithm can quickly and accurately detect the time section when commercials arise， and count the frequency of the commercials broadcasting from the radio， and the algorithm proposed is robust. References | Related Articles | Metrics

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A Topic Domain Identification Model Combining Local and Global Characteristics KOU Yue， XU Hong-bin， SHEN De-rong， NIE Tie-zheng 2018, 39 (2):  176-180.  DOI: 10.12068/j.issn.1005-3026.2018.02.006 Abstract ( 815 )   HTML   PDF (560KB) ( 848 )   Traditional identification techniques focus on a single domain and lack the mutual collaboration among different domains， which often lead to dumb results. So， a topic domain identification model combining local and global characteristics is proposed.Local identification is performed based on entities’ local characteristics within one domain. On the other hand， these local identification results tend to be consistent with each other based on the global characteristics such as the collaboration and relevance among domains， which can maintain the accuracy of identification effectively. In addition， some improvements are made for the algorithm of topic domain identification， including similarity matrix updating， collaboration quantifying and iteration terminating. The experiments demonstrate the feasibility and effectiveness of the proposed model. References | Related Articles | Metrics

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Pulmonary Nodules Detection Based on 3D Features from CT Images WANG Bin， ZHAO Hai， ZHU Hong-bo， PAK Chun-hyok 2018, 39 (2):  181-185.  DOI: 10.12068/j.issn.1005-3026.2018.02.007 Abstract ( 934 )   HTML   PDF (2172KB) ( 1516 )   A detection method based on the center continuity is proposed to improve the performance of pulmonary nodules detection. CT images are segmented by using SLIC (simple linear iterative clustering) superpixel algorithm in the method. Superpixels are merged according to the similarity to extract pulmonary areas and suspected pulmonary nodule areas， which reduces the missing rate of suspected pulmonary nodules. Suspected pulmonary nodules are diagnosed as positive which keeping center continuous in 3D space. All of CT images in experiments are obtained from Shanghai chest hospital and LIDC database. The experimental results of the improved algorithm show that sensitivity is 86.36% and false positive is 1.76. References | Related Articles | Metrics

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MRI Brain Tissue Automatic Extraction Algorithm Based on Modified BET YANG Jin-zhu， LU Lin， CAO Peng， ZHAO Da-zhe 2018, 39 (2):  186-190.  DOI: 10.12068/j.issn.1005-3026.2018.02.008 Abstract ( 833 )   HTML   PDF (3022KB) ( 1258 )   Based on modified brain extraction tool(BET)， an automatic extraction algorithm is proposed for brain MRI(magnetic resonance imaging). Firstly， the algorithm combining image gradient information can estimate the center of gravity(COG) of brain more accurately; secondly， it builds a new brain surface deformation force. Edge force is introduced into the expansion force perpendicular to the tangent of brain surface， which could suppress the brain tissue leaking and over-segmentation problem. Experiments are conducted on the algorithm proposed to automatically extract brain tissue of MRI brain images， and the results show the more accurate extraction of brain tissue， especially at brain tissue edges， compared with the BET method. References | Related Articles | Metrics

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Quantitative and Intelligent Diagnosis Method of Hip Dislocation Based on 3D-CT Images LI Hong， SUN Hang， LIU Sheng-nan， PAN Shi-nong 2018, 39 (2):  190-194.  DOI: 10.12068/j.issn.1005-3026.2018.02.009 Abstract ( 633 )   HTML   PDF (1656KB) ( 762 )   Considering that the spherical surface of the femoral head should be approximately concentric with that of the acetabulum， an effective method based on three dimensional image segmentation and spherical surface fitting was proposed， with some detailed algorithm designed. First， the three dimensional segmentation was implemented on the femur and acetabulum to obtain respective independent data. After extracting the valid data of the femoral head and acetabulum boundary and removing the error points， the least square method was applied to fit the spherical surface of the femoral head and the surface of the acetabulum. Then the respective sphere center distance between two spherical surfaces was calculated， thus determining whether the acetabulum is dislocated or not. The results of experiments show that the method proposed can provide the distance for hip replacement and improve the diagnostic accuracy. References | Related Articles | Metrics

Materials & Metallurgy

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Bubble Coalescence/Breakage and Movement in the Ladle with Argon Blowing GOU Da-zhao， WANG Wei-xian， GENG Dian-qiao， LEI Hong 2018, 39 (2):  195-199.  DOI: 10.12068/j.issn.1005-3026.2018.02.010 Abstract ( 855 )   HTML   PDF (1168KB) ( 1250 )   A mathematical model for the gas-liquid flow field in the ladle with argon blowing was built based on the Euler-Euler model and population balance model(PBM)， which considered the effects of the drag force， lift force， turbulent dispersion force and bubble coalescence and breakage in ladle with argon blowing. The effects of bubble coalescence and breakage on the gas holdup， bubble velocity and mixing time were investigated and further compared with those from the constant diameter model. The numerical results show that the predicted data of the PBM agrees well with the experimental one. The bubble diameter is the largest one in center area and reduces gradually from the center to the gas-liquid interface， therefore it becomes the smallest one at gas-liquid interface in the ladle. At the ladle central axis， the bubble velocity firstly increases drastically and then decreases gradually， however， it decreases greatly near the free surface. References | Related Articles | Metrics

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Combustion Characteristics of Calcium Carbide Furnace Off-Gas in a New Type Combustor of Twin Burn Annular Shaft Kiln RONG Wen-jie， LI Bao-kuan， QI Feng-sheng 2018, 39 (2):  200-204.  DOI: 10.12068/j.issn.1005-3026.2018.02.011 Abstract ( 734 )   HTML   PDF (867KB) ( 1185 )   A 3D mathematical model of flow， combustion and radiation heat transfer was established to study the combustion performance of calcium carbide furnace off-gas(CCFG)in the combustion chamber and to investigate the impact on combustion from different excess air coefficient. It is found that the flue gas from CCFG burning is blocked by a baffle wall and forms a big vortex， thus the high temperature zone is inside the baffle wall. With the increase of excess air coefficient， the fuel conversion degree becomes larger， but even if the excess air coefficient was up to 1.3， there remained CO in the combustion chamber exit， i.e.， a small amount of fuel will burn out in the kiln chamber. As the excess air coefficient increases， the average temperature of gas increases first and then decreases at the exit of combustion chamber. References | Related Articles | Metrics

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Experimental Study on One-Step Roasting of Bayan Obo Tailings ZHENG Qiang， WU Wen-yuan， BIAN Xue 2018, 39 (2):  205-210.  DOI: 10.12068/j.issn.1005-3026.2018.02.012 Abstract ( 703 )   HTML   PDF (1209KB) ( 673 )   The roasting process of Bayan Obo tailings in C-Ca(OH)2-NaOH was investigated by means of thermogravimetric and differential thermal analysis(TG-DTA)and X-ray diffraction(XRD). The influences of the roasting temperature， roasting time， coal content， Ca(OH)2 dosage and NaOH dosage were explored on the decomposition of rare earth minerals and the reduction of hematite. The results showed that the hematite was reduced to magnetite(magnetic susceptibility: 2.37)and the rare earth minerals were decomposed by forming rare earth oxides(the leaching ratio of REO: 98.39%)under the optimal conditions. The optimal conditions were as follows: the roasting temperature of 650℃， the roasting time of 60min， the coal content of 2%， Ca(OH)2 dosage of 4% and NaOH dosage of 2%. References | Related Articles | Metrics

Mechanical Engineering

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Influence of Impact Energy on 8Mn-2Cr-Si Steel Abrasive-Wear Properties SHENG Zhong-qi， SONG Bai-long， WEI Shi-cheng， WANG Yu-jiang 2018, 39 (2):  211-215.  DOI: 10.12068/j.issn.1005-3026.2018.02.013 Abstract ( 668 )   HTML   PDF (1612KB) ( 850 )   The abrasive-wear properties of 8Mn-2Cr-Si steel were tested under different impact energy conditions. XRD(X-ray diffractometer)was used to investigate the structural transformation of the impacted wear surface， and SEM(scanning electron microscope)was used to investigate the morphology of wear surface and subsurface in order to study wear mechanism. The results show that impact-induced martensite phase transformation occurs during the wear. With the impact energy growing， the amount of martensite transformation increases， the work hardening effect improves and the wear loss increases. The reason is the wear mechanisms are different under different impact energy conditions. Besides， the grains embedded in the substrate during the plastic deformation will become sources of stress concentration. Thus the fatigue cracks will grow and propagate to the wear surface gradually under the circulation impact， causing large impact-flaking， finally making the material failure. References | Related Articles | Metrics

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Analysis of Structural Dynamic Characteristics Based on Vibration Environment Prediction LI Bo-bo， YUAN Hui-qun， WANG Guang-ding， ZHAO Tian-yu 2018, 39 (2):  216-220.  DOI: 10.12068/j.issn.1005-3026.2018.02.014 Abstract ( 654 )   HTML   PDF (1119KB) ( 1029 )   Aiming at the limitation of load testing technology， this paper proposes an analytical method for the dynamic analysis of engineering structure using the acceleration information. The test acceleration is used as input excitation of the battery frame assembly model， then the simulation analysis of dynamic characteristic is used to calculate the strength distribution and dynamic response of the battery frame assembly model of heavy tractor. At the same time， the accuracy of the method is verified by comparing with the test results of actual roads. Research results show that the proposed method can be used to solve the dynamic characteristics of engineering structures accurately and effectively， and the method has important engineering application value for enterprises in shortening the research and development period of products. References | Related Articles | Metrics

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Forced Vibration Analysis of Fluid Conveying Pipe with Both Ends Supported SUN Zhi-li，YU Ying，ZHAO Qian-li，CHAI Xiao-dong 2018, 39 (2):  221-225.  DOI: 10.12068/j.issn.1005-3026.2018.02.015 Abstract ( 637 )   HTML   PDF (404KB) ( 803 )   The forced vibration of fluid conveying pipe with elastic support was investigated. Euler-Bernoulli beam was adopted to simplify the mechanical model of the pipe. Greens Function method was used to deduce the dimensionless differential equation of forced vibration and Greens Function of pipes with general supporting formats was obtained. Finally， the general expression of the deflection was obtained. On this basis， dynamic responses of the pipe with one end fixed and the other elastically supported was studied. Differential Transformation method and Galerkin’s Method were utilized to verify the validity and accuracy of the proposed method， and the responses of the pipe under concentrated and distributed force were investigated. The proposed model has advantages compared with other numerical methods because it is capable for offering precise closed solutions. References | Related Articles | Metrics

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An Isolated Chain Rheological Shear Stress Model with Distance Weighted Coefficients MA Liang， XIAO Ping， WANG Ren-sheng， XIU Shi-chao 2018, 39 (2):  226-231.  DOI: 10.12068/j.issn.1005-3026.2018.02.016 Abstract ( 631 )   HTML   PDF (951KB) ( 694 )   For reducing the error in calculating shear stress of high volume concentration magnetorheological fluids by applying standard isolated chain theoretical model， a new rheological model was proposed to evaluate interaction of magnetic chains by distance weighted coefficients. A Monte Carlo program was written for simulating position coordinates and direction of magnetic moment of carbonyl iron particles in magnetorheological fluids system， with two distance-related coefficients output. Comparing theoretical values of standard and distance weighted shear stress model with four magnetorheological fluids’ testing data that measured by rheometer， results indicated that distance model has higher computational accuracy at the whole experimental range of magnetic field than that using standard isolated chain-based one， and it generally aligned with rheological results， which proves interaction force between magnetic chains is one of impact factors that can significantly affect rheological characteristic of magnetorheological fluids. References | Related Articles | Metrics

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Experimental Analysis of Lumbar Vibration Characteristic Based on EMG and Acceleration Signal DONG Rui-chun， GUO Li-xin， YUAN Sheng， GE Wei 2018, 39 (2):  232-236.  DOI: 10.12068/j.issn.1005-3026.2018.02.017 Abstract ( 707 )   HTML   PDF (722KB) ( 1061 )   A vibration experiment is conducted to study the influence of automobile seat on human lumbar muscle tissue during whole body vibration. Lumbar muscle response is analyzed by calculating root mean square (RMS) of electromyography (EMG) signal， and the vibration energy transmitting characteristic of lumbar tissue is studied by analyzing the vibration transmissibility. At last the vibration transmissibility and EMG RMS of all subjects under different lumbar support conditions are conducted statistically. The experiment result indicates that when lumbar support parameter is d2 (appropriate support)， vibration transmissibility and EMG RMS are minimum， while other two lumbar support parameters d1(no support) and d3 (excessive support) magnify lumbar vibration transmissibility and EMG RMS. The experiment proved that appropriate lumbar support of automobile seat can reduce effect degree of vibration on human lumbar. References | Related Articles | Metrics

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Modelling and Simulation of a Surface Stress-Included Microcantilever-based Mass Sensor MA Shu-jun， XIU Qiang 2018, 39 (2):  237-241.  DOI: 10.12068/j.issn.1005-3026.2018.02.018 Abstract ( 695 )   HTML   PDF (618KB) ( 903 )   A theoretical model， which takes surface stress into account by applying Rayleigh-Ritz theorem， for a cantilever-based mass sensor is proposed， in order to consider the surface stress induced by the adsorbed layer or coating of different materials on the cantilever resonator and to further enhance the accuracy and performance of the cantilever sensor. Stress parameter is introduced into the governing equation of the cantilever vibration to adjust the mode shape function， and the influence of the surface stress towards the vibration is systematically analyzed. With this model， the position and mass of the particle can be precisely determined through the frequency shifts of the microcantilever before and after the particle adsorption. The accuracy and the reliability of this method were validated by finite element simulation. References | Related Articles | Metrics

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Optimized Layout Design for Cutterhead’s Disc Cutters Based on Rock-Breaking Specific Energy GUO Wei， LIU Xiao-qing， LIU Jian-qin， SUN Hong-yan 2018, 39 (2):  242-248.  DOI: 10.12068/j.issn.1005-3026.2018.02.019 Abstract ( 803 )   HTML   PDF (765KB) ( 1107 )   The paper proposed a research model based on the CSM model， which was deduced by Colorado School of Mines， to minimize the unbalanced radial force and overturning moment. The model followed the principle of cutterhead minimum specific energy and utilized the normal genetic algorithm to optimize the spacing of the center cutters， the normal cutters and the gage cutters， and in turn， to improve the polar angle of the normal cutters and the gage cutters. Taking the TB880E cutterhead as an object， the research revealed that when the cutter spacing of center cutters and the normal cutters have been improved， the specific energy can be reduced by about 1.53%. Similarly， when the tilt angles of the gage cutters have been optimized， the specific energy can be reduced by about 1.10%. When the polar angles of the normal cutters and the gage cutters have been improved， the unbalanced radial force can be reduced to 0.1265N， and the overturning moment can be reduced to 0.7591N/m， which may decrease the deformation of the cutterhead. The present research can be applied in the optimization design of the locations of the disc cutters on the cutterhead and in the prediction of the energy consumption of rock fragmentation process， which can reduce the energy of the rock fragmentation and improve the boring efficiency. References | Related Articles | Metrics

Resources & Civil Engineering

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New Process of Comprehensive Utilization for Daxigou Refractory Siderite Ore ZHANG Xiao-long， HAN Yue-xin， LI Yan-jun， TANG Zhi-dong 2018, 39 (2):  248-253.  DOI: 10.12068/j.issn.1005-3026.2018.02.020 Abstract ( 807 )   HTML   PDF (889KB) ( 946 )   Daxigou refractory siderite ore was investigated through high intensity magnetic preconcentration-magnetization roasting-magnetic separation. The results showed that high intensity magnetic concentrate with iron grade of 28.47% and recovery of 96.78% was obtained under the test conditions that the grinding fineness of 55% ores is less than 74μm， high intensity magnetic field for roughing is 318kA/m and magnetic field for scavenging is 717kA/m. Iron concentrate with iron grade of 59.29% and recovery of 87.50% was obtained under roasting temperature of 700℃， roasting time of 40min with neutral atmosphere， 95% grinding fineness less than 43μm and low intensity magnetic field intensity of 104kA/m. The analysis results of XRD， optical microscope and VSM showed that refractory siderite and limonite are transformed into easily separated magnetite by roasted， meanwhile， the surface of the newly generated magnetite showed loose and porous， symbiosis between magnetite and gangue minerals is close， and the magnetization intensity and specific susceptibility increase greatly. References | Related Articles | Metrics

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Effects of Confining Pressure Paths on Strength and Deformation of Calcareous Argillaceous Cemmented Sandstones ZHAO Yong-chuan， YANG Tian-hong， QIN Tao， WANG Hong 2018, 39 (2):  254-259.  DOI: 10.12068/j.issn.1005-3026.2018.02.021 Abstract ( 772 )   HTML   PDF (1074KB) ( 809 )   Considering the characteristics of short diagenetic age and high intensity mining of Jurassic weak cemented sandstone in western China， the conventional triaxial compression tests， different unloading rates of confining pressure in triaxial compression tests and multi-stage triaxial tests were conducted to study the effects of confining pressure path on the strength and deformation. The results show that: the peak strength， residual strength， peak strain， elastic modulus and Poisson ratio depend on the confining pressure strongly， and the cohesion and internal friction angle of the sandstones in western China are lower than those of other sandstones. As the confining pressure increases， the failure mode transits from single plane fracture to complex multi-fracture. During the loading process， the change of confining pressure can remarkably affect the strength and the deformation characteristic by restricting lateral dilatation and increasing the angle of internal friction. The effect of unloading and loading confining pressure path on the mechanical parameters can provide references for the optimization of mining velocity and the support design of the surrounding rock masses. References | Related Articles | Metrics

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Mechanics Performance Analysis of Precast Rectangle Box Culvert and Damage Prediction of Key Parts WANG Shu-hong， JIERULA Alipujian， WANG Peng-yu， LIU Wei-hua 2018, 39 (2):  260-265.  DOI: 10.12068/j.issn.1005-3026.2018.02.022 Abstract ( 788 )   HTML   PDF (2448KB) ( 1208 )   Taking the prefabricated construction section of the Hunnan New Development Area utility tunnel construction in Shenyang， China as research background， the numerical simulations of structural deformation and stress distribution of single precast rectangle box culvert at different burial depths were carried out through the general finite element analysis software ABAQUS. In order to modeling the actual stress of the precast rectangle box culvert as accurately as possible， the reinforcement was carried out according to the actual engineering application. This model simulated the different buried depths by changing the load of roof and side wall， where a uniform pressure was loaded on the roof and the lateral pressure varied linearly was loaded on the side wall. Finally this paper analyzed the structural deformation and stress distribution of precast rectangle box culvert at different buried depths， pointing out the existing structural safety problems and potential failure modes， to provide a theoretical reference for the design and construction of utility tunnel engineering. References | Related Articles | Metrics

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Experimental Research on Maximum Effect Range of Fluid Migration in Cavity Construction Period of Salt Rock Gas Storage LIU Huan， WANG Shu-hong， XU Su-guo， LIANG Wei-guo 2018, 39 (2):  266-271.  DOI: 10.12068/j.issn.1005-3026.2018.02.023 Abstract ( 639 )   HTML   PDF (817KB) ( 764 )   The experiment of fluid migration is studied through staining method in the three-dimensional cavity model of salt rock gas storage， and the maximum influencing range of fluid migration is analyzed. The study results show as follows: the upper and lower boundaries of the maximum influencing range of fluid migration move towards the top of cavity with the increase of brine concentration， which facilitates the salt rock solution of the side walls of upper cavity. With the increase of water injection flow， the increase of radial migration velocity facilitates the salt rock solution of side walls， and the lower boundary of the maximum influencing range of fluid migration moves towards the bottom part of cavity， which facilitates the salt rock solution of lower part of middle tube mouth. The engineering values of the maximum influencing range of fluid migration are obtained through converting experimental values under the combined conditions of different brine concentrations (25， 50，75g/L)， water injection flows (60， 80， 100m3/h) and tubes spacing (28，42， 56， 70， 84， 98m). Research results and method can provide the reference and approach for improving cavity constructing efficiency and controlling cavity shape. References | Related Articles | Metrics

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Experimental Investigation on Channel Columns with Complex Edge Stiffeners and Cap Shaped Stiffeners Under Eccentric Compression SONG Bo， WANG Lian-guang， WANG Chun-gang 2018, 39 (2):  272-277.  DOI: 10.12068/j.issn.1005-3026.2018.02.024 Abstract ( 651 )   HTML   PDF (747KB) ( 932 )   Eighteen simply supported eccentric compression specimens were tested to investigate the ultimate bearing capacity， instability mode， and deformation of three types of complex edge stiffened channels， including no stiffeners， intermediate cap shaped stiffeners in the web， intermediate cap shaped stiffeners in the web and the flanges. Results show that offset of the effective centroid has a significant effect on the bearing capacity of eccentric compressed members. Cap shaped stiffeners can effectively reduce the width-to-thickness ratio of the element and obviously increase the ultimate load bearing capacity as well as the steel utilization ratio of elements， but distortional buckling can become the dominate failure mode. Under the same conditions， the load bearing efficiency of plate with intermediate cap shaped stiffeners is improved by 15%~70%. References | Related Articles | Metrics

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Influence of Inorganic Carbon on Nitrogen Removal Efficiency During the ANAMMOX Process ZHU Tong， LIANG Qi-yu， XIE Yuan-hua ，MA Yong-guang 2018, 39 (2):  278-283.  DOI: 10.12068/j.issn.1005-3026.2018.02.025 Abstract ( 779 )   HTML   PDF (662KB) ( 932 )   The influence of inorganic carbon(IC) on anaerobic ammonium oxidation(ANAMMOX) process was investigated by evaluating the nitrogen removal efficiency in an up-flow ANAMMOX reactor. Results show that the nitrogen removal efficiency decreases significantly when stop adding IC into influent water. The nitrogen removal efficiency recovers and increases gradually when the mass concentration ratio of influent IC to total inorganic nitrogen(TIN) is 0.2~0.4. Increasing the ratio from 0.4 to 1.0 cannot bring a better nitrogen removal efficiency. When a new reactor was started up with the ratio of 0.4， the achieved nitrogen removal efficiency comes up to 1.04kg·m-3·d-1 after 61days stable operation. The ANAMMOX bacteria in the new reactor present higher activity than that in the previous reactor. Results suggest that IC provides a suitable carbon source and plays a catalytic role in the ANAMMOX process. Sufficient IC is important to maintain the activity of ANAMMOX bacteria and the stability of the nitrogen removal efficiency. 0.4 is the optimal ratio in the influent for ANAMMOX process. References | Related Articles | Metrics

Management Science

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Retailer Enterprises’ Order Decision with the Chattel Mortgage After Acceptance Financing Model SHI Jun， ZHUANG Xin-tian， MA Chun-lan， LI Xiao-qing 2018, 39 (2):  283-287.  DOI: 10.12068/j.issn.1005-3026.2018.02.026 Abstract ( 871 )   HTML   PDF (375KB) ( 877 )   A new enterprises’ decision-making model was developed based on an innovative logistics mode， ie， chattel mortgage after acceptance(CMAA). The optimal ordering and pricing strategies were analyzed when supply chain enterprises adopt CMAA financing under the condition that the retailer’s own capital is constrained， thus the ordering interval and optimal ordering quantities in CMAA model were derived. It is shown that the overall revenue of retailer enterprises is related to the ordering quantities in that model. Due to the participation of banks， when the optimal ordering quantities of retailers are reached， the performance of retailer enterprises under capital constraints is improved significantly. References | Related Articles | Metrics

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Dual-Channel Supply Chain Coordination with Manufacturer’s Capital Constraint ZHAO Liang， ZHUANG Xin-tian， SHI Jun 2018, 39 (2):  288-292.  DOI: 10.12068/j.issn.1005-3026.2018.02.027 Abstract ( 664 )   HTML   PDF (336KB) ( 800 )   Considering a dual-channel supply chain involving one capital constrained manufacturer and one independent retailer under stochastic demands， the issue of dual-channel supply chain coordination with prepayment financing including the price discount factor was investigated. Under the condition that the manufacturer is the Stackelberg leader， the inventory coordination problem between the manufacturer and the retailer was studied， and a revenue-sharing contract model was established for the dual-channel supply chain coordination. Furthermore， the calculation formulas of contract parameters were given， and the effects of price discount and initial capital on the supply chain and its members were analyzed. Finally， a numerical example verified the effectiveness of the dual-channel supply chain coordination and the effects of the other relevant parameters. References | Related Articles | Metrics

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Transportation Cost， Scale Effect and Regional Economic Disparity: Taking Liaoning as an Example ZHANG Fang， CHEN Kai 2018, 39 (2):  293-296.  DOI: 10.12068/j.issn.1005-3026.2018.02.028 Abstract ( 667 )   HTML   PDF (364KB) ( 1118 )   Based on the new economic geography theory， a market potential model and a Krugman wage equation were estimated with the data of the prefecture cities in Liaoning Province， and how transportation costs affect the regional salary disparities in Liaoning was analyzed and then the scale effect was calculated. The results showed that the overall economy in Liaoning takes on a certain increase of scale payment， and that the transportation costs between any other two cities in Liaoning apart from Shenyang and Dalian have negative effects on regional economic levels and scales， but through their more developed transportation systems， Shenyang and Dalian have radiative effects on Liaoning’s economy. Therefore， policies aiming at improving the transportation systems are suggested to reduce the regional economic disparities in Liaoning Province. References | Related Articles | Metrics

Mathematics

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Robust Passive Control for Uncertain Switched Singular Systems with Multiple Time-Delays YANG Dong-mei， CHEN Shan-shan 2018, 39 (2):  297-300.  DOI: 10.12068/j.issn.1005-3026.2018.02.029 Abstract ( 560 )   HTML   PDF (295KB) ( 748 )   The concept of passive source is extended to the switched singular systems with multiple time-delays. The problem of robust passive control for a class of switched singular systems with both uncertainties and multiple time-delays is studied， and some of these conditions need to satisfy the hypothesis. First， by means of generalized Lyapunov function and linear matrix inequality， the sufficient conditions are given for the asymptotic stability and strictly passive of uncertain switched singular systems with multiple time-delays. Moreover， the qualified robust passive controller is designed according to the existing conditions， so that the switched singular systems can be asymptotically stable and strictly passive. Finally， numerical examples illustrate the effectiveness of the approaches. References | Related Articles | Metrics

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Structure Functions on Normal Ruled Surface in 3-D Euclidean Space YU Yan-hua， YUE Li-dong 2018, 39 (2):  301-304.  DOI: 10.12068/j.issn.1005-3026.2018.02.030 Abstract ( 888 )   HTML   PDF (288KB) ( 925 )   As special non-developable ruled surface， the normal ruled surface has good algebraic and geometric properties. Using the classical methods of differential geometry， the structure functions of the normal ruled surface in 3-D Euclidean Space are studied. According to the definition and standard equation of non-developable ruled surface in 3-D Euclidean Space， the definition and standard equation are given to the normal ruled surface. Based on the definition and standard equation of the normal ruled surface， the deep relation of the structure functions is obtained. Then some conclusions about the directrix， the striction line and the structure functions are obtained. By discussing the normal ruled surfaces of general helices and Mannheim curves in 3-D Euclidean Space， conclusions can be drawn that the normal ruled surfaces of general helices are positive spiral surfaces and the normal ruled surfaces of Mannheim curves are binormal ruled surfaces of their Mannheim partner curves. References | Related Articles | Metrics