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15 June 2015, Volume 36 Issue 6 Previous Issue    Next Issue
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Information & Control

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An Applied Research of Sparsity SVDD Method to the Fault Detection WANG Guo-zhu， LIU Jian-chang， LI Yuan 2015, 36 (6):  761-765.  DOI: 10.12068/j.issn.1005-3026.2015.06.001 Abstract ( 946 )   HTML   PDF (543KB) ( 903 )   Fault detection based on the basic SVDD (support vector data description) method is not good at the processing of large sample data， and the modeling and process monitoring is time-consuming. The sparse characteristics of the original data in high dimension space was studied， according to which the first k high dimensional distribution edge data points were selected to carry out the SVDD modeling. Through theoretical derivation and simulation analysis， it was showed that the modeling and detection speed could be effectively improved by the proposed method， and the large sample data could be modeled by using the selected small sample， which could handle the classification problems of SVDD method on solving large sample data; meanwhile， this method did not affect the accuracy of fault detection. The effectiveness of the proposed method was illustrated by applying it to the monitoring of TE process. References | Related Articles | Metrics

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Position Estimation for Single-Lens Stereovision System Using Prism CUI Xiao-yu， ZHAO Yue， FAN Qun-an， WEI Yong-tao 2015, 36 (6):  765-768.  DOI: 10.12068/j.issn.1005-3026.2015.06.002 Abstract ( 937 )   HTML   PDF (284KB) ( 900 )   In order to improve the theoretical model of prism based single-lens stereovision system， and enhance the precision of three-dimensional reconstruction， a parameter simplifying method for prism as well as a position estimation method that based on geometrical optics were proposed. First， a perspective projection model for prism based single-lens stereovision system was derived. Then， the parameters of prism which could express its position were decreased to six by making use of rotational vector and the relationship between points. At last， these six parameters could be solved out as a result of nonlinear optimization， and an accurate position of prism could be obtained. Experimental results indicated that the average reprojection error of proposed method was less than 0.5 pixel， the average error for three dimensional reconstruction was 2.22mm. This method could be used for calculating the epipolar geometry of stereo matching. It could increase the precision of three-dimensional reconstruction up to 2~3 times. References | Related Articles | Metrics

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Kernelized Extreme Learning Machine in Distributed Environment ZHAO Xiang-guo， BI Xin， ZHANG Zhen， YANG Hong-bo 2015, 36 (6):  769-772.  DOI: 10.12068/j.issn.1005-3026.2015.06.003 Abstract ( 1000 )   HTML   PDF (489KB) ( 1090 )   With the exponentially increasing volume of training data， the performance of centralized ELM with kernels suffers due to large matrix operations. A distributed algorithm named MapReduce based kernelized ELM (MR-KELM) was proposed， which realized an implementation of ELM with kernels on MapReduce in the cloud. The kernel matrix generated by distributed radial basis function was decomposed and then the output weights by distributed multiplication of matrix and vector were calculated by the proposed algorithm. Communications and data exchanges in distributed matrix operations were reduced and good scalability was achieved by MR-KELM. Extensive experiments on synthetic datasets were conducted to verify the training performance and scalability of MR-KELM. Experimental results showed that MR-KELM was effective and efficient for massive learning applications. References | Related Articles | Metrics

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A Novel Modeling Method for Relationships Between Resources and Service Performance ZHANG Bin， WANG Lin， ZHAO Xiu-tao， ZHANG Chang-sheng 2015, 36 (6):  773-776.  DOI: 10.12068/j.issn.1005-3026.2015.06.004 Abstract ( 768 )   HTML   PDF (470KB) ( 784 )   The relationship model between resources and service performance is a key to the proper virtual resource allocation for services in cloud environment. However， the accuracy of these non-linear relationship models is usually significantly influenced by the scale of training data. Aiming at the shortcomings of related work， a dynamic service performance modeling method named CSDM， which combines collaborative filtering recommendation and support vector regression， was proposed. In CSDM， for better accuracy， both performance models were trained at service deployment time and runtime， and the one with lower MAE was selected to estimate the performance under given resource status. In addition， a merit-based threshold was introduced to reduce training costs of performance models. The experimental results showed that CSDM had higher accuracy on different scales of training data， and the merit-based threshold had a significant effect on the prediction accuracy as well as the modeling efficiency. References | Related Articles | Metrics

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Query Recommendation for Exploratory Search Process MA Chao， ZHANG Yin， ZHANG Bin 2015, 36 (6):  777-780.  DOI: 10.12068/j.issn.1005-3026.2015.06.005 Abstract ( 866 )   HTML   PDF (448KB) ( 843 )   Query recommendation is an important tool for improving searching efficiency. But traditional recommendation method cannot provide good recommendations for exploratory search. A novel model based on search behaviors for the above problem was proposed，which successfully build the exploratory search process by tentative query refinement and deterministic query refinement. Then a query recommendation algorithm based on the three factors affecting exploratory search process was proposed. Finally the results of comparative experiments showed that this model and algorithm achieved a good effect. References | Related Articles | Metrics

Materials & Metallurgy

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Phase Transformation Behaviors of Boron-Vanadium Microalloyed Steels During the Continuous Cooling KIM Kwang-su， GAO Cai-ru， DU Lin-xiu 2015, 36 (6):  780-785.  DOI: 10.12068/j.issn.1005-3026.2015.06.006 Abstract ( 621 )   HTML   PDF (1085KB) ( 900 )   In order to develop a low cost and high performance boron-vanadium microalloyed steel and establish its TMCP process， the transformation mechanism of the test steel under continuous cooling was studied and the static and dynamic CCT curves of the test steel were also obtained by means of MMS-200 thermo-mechanical simulator. The results showed that， by addition of the trace boron， the stability of overcooling austenite of the vananium microalloyed steel was increased， and the formation of acicular ferrite was promoted， while the bainite can be obtained under wider cooling rates. Compared to the deformed steel， bainite was the major microstructure which obtained in the undeformed steel under the very slow cooling rate even only 0.5℃/s， but when the cooling rate was higher than 5℃/s， fully bainite was obtained in both the deformed and undeformed steels. The stability of austenite was reduced and the formation of the ferrite was promoted by deformation， thus ferrite transformation proceeded under cooling rate lower than 2℃/s and 15℃/s in the boron steel and non-boron steel， respectively. For vanadium microalloyed steel， boron is beneficial to obtaining high strength bainite， therefore when the cooling rate is higher than 5℃/s， Vickers hardness of boron steel is higher than that of non-boron steel under deformed and undeformed status. References | Related Articles | Metrics

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Purification of the Leaching Liquid from the Boron-Rich Slags by the Alkaline Leaching Method Under Ordinary Pressure and the Preparation of Borax XUE Xiang-xin， DONG Meng-ge， YANG He， SONG Li 2015, 36 (6):  786-790.  DOI: 10.12068/j.issn.1005-3026.2015.06.007 Abstract ( 718 )   HTML   PDF (554KB) ( 819 )   Based on the alkaline leaching method under ordinary pressure， the generation， removal mechanism and effects of the impurities in the boron leaching liquid were investigated， using NaOH as sodium treatment reagent and boron-rich slags as raw materials. Phase compositions and the morphologies of the precipitates after the purification and crystallization products of borax were analyzed by XRD and SEM. The results indicated that the primary impurities in the boron leaching liquid were Ca2+ and Si4+ impurity. The removal effect with NaHCO3 for Ca2+ was obvious and the optimal amount of NaHCO3 was 3g.There was great effect of the pH value of the leaching liquid on the removal of Si4+ when the pH value was 9.0， the removal rate of Si4+reached its maximum value of 99%. Thus “one-step method” purified technology which combines the process of removing Ca2+ and Si4+ impurity was achieved and with great removal efficiency. Well-crystallized borax was obtained from the purified leaching liquid after treatments of evaporation and concentration. References | Related Articles | Metrics

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Experimental Studies on Self-reduction for the Pellets Made of Iron-contained Dust and Sludge from a Steel Enterprise MAO Rui， ZHANG Jian-liang， LIU Zheng-jian， WANG Fei 2015, 36 (6):  790-795.  DOI: 10.12068/j.issn.1005-3026.2015.06.008 Abstract ( 660 )   HTML   PDF (765KB) ( 826 )   Using gravity dust and converter sludge as the main raw materials，the cold bonded pellets were formed with some reducing agents， binders and water. The experiments of self-reduction for pellets in high temperature were conducted. The results showed that mixing gravity dust and converter sludge and making them into cold bonded pellets can not only make up the inadequacy of briquetting characteristic by forming with single material， but also achieve the self-reduction of pellets and fully recycle the valuable substance such as Fe， C and CaO. Metallization and dezincification ratio of pellets all rise with the increase of reaction temperature and can reach 91.35 % and 99.25 % respectively. As reaction time increase， metallization and dezincification ratio also rise gradually and can reach 50.68 % and 75.82 % respectively when the reaction lasts for 5minutes. As carbon addition amount rise， metallization and dezincification ratio show the trend of decrease after the first increase， but the change is very small. References | Related Articles | Metrics

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Study on the Intermetallics (Mg，Zn)12Ce and (Mg，Zn)11Ce HUANG Ming-li， LI Hong-xiao， DING Hua 2015, 36 (6):  796-800.  DOI: 10.12068/j.issn.1005-3026.2015.06.009 Abstract ( 582 )   HTML   PDF (543KB) ( 763 )   Phase composition，crystal structure and the relationship the phase equilibria in Mg-rich corner of Mg-Zn-Ce system at 300℃ were studied. The results showed that a substitution binary solid solution of Mg12Ce identified as (Mg，Zn)12Ce and a linear ternary compound identified as (Mg，Zn)11Ce (τphase) were confirmed in Mg-rich corner of Mg-Zn-Ce system. The solid solubility of Zn in (Mg，Zn)12Ce is about 0~7.3% (atomic fraction)， and the crystal structure of which is a body-centered tetragonal lattice structure. The Zn content of the linear ternaty compound τ phase is from 8.5% to 43.5% (atomic fraction)， and the crystal structure of it is a C-centered orthorhombic lattice. Both (Mg，Zn)12Ce and τ phase were identified to be in two-phase equilibrim with α(Mg). A three-phase equilibrium of Mg+(Mg，Zn)12Ce+τ in Mg-rich corner of Mg-Zn-Ce system was also identified. References | Related Articles | Metrics

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Study on the Preparation Process for CeO2 Superfine Powder WU Wen-yuan， XUE Shou-feng， BIAN Xue， WANG Zhen-feng 2015, 36 (6):  800-804.  DOI: 10.12068/j.issn.1005-3026.2015.06.010 Abstract ( 801 )   HTML   PDF (596KB) ( 844 )   Compared with traditional precipitation process， a short process for preparation of CeO2 superfine powder was investigated by ultrasonic spray pyrolysis using CeCl3 solution as raw materials. The thermal decomposition process of CeCl3·7H2O was examined by TG-DTA experiments. CeO2 was prepared by the precipitation and spray pyrolysis method respectively at 600℃， which was characterized by XRD， SEM and TEM. The two methods were compared in terms of products， processes and the resource comprehensive utilization. The results showed that the reaction of CeCl3·7H2O at 25~233℃ was a dehydration reaction， the thermal decomposition start temperature was 500℃ and end temperature was 583℃. The product synthesized via ultrasonic spray pyrolysis has good dispersion， regular morphology and the particle size distribution between 0.11~0.80μm， while the morphologies of the products obtained by precipitation process was not regular and agglomerate was also observed. Obviously， ultrasonic spray pyrolysis method is a clean technology with short process， high level resource comprehensive utilization and controllable product morphologies. References | Related Articles | Metrics

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Numerical Simulation of Electroslag Remelting Process of Hollow Ingot with T-shape Current Supplying Mold CHEN Xu， LIU Fu-bin， JIANG Zhou-hua， LI Xing 2015, 36 (6):  805-810.  DOI: 10.12068/j.issn.1005-3026.2015.06.011 Abstract ( 676 )   HTML   PDF (1284KB) ( 793 )   A three dimensional quasi-steady state mathematical model of the slag bath and hollow ingot has been established based on the newly developed electroslag remelting (ESR) technology for hollow ingot manufacture. The electromagnetic， flow and temperature fields during the electroslag remelting hollow ingot process with and without the current supplying mold (CSM) have been simulated using commercial software ANSYS. Computational results showed that the maximum current density and joule heat of the slag bath were obtained in the conductive section of T-shaped CSM， where the fluid flow velocity was much faster and the temperature field of the slag bath was more uniform， and the metal pool shape was shallower. The CSM can keep slag bath and metal pool temperature constantly during the exchange of electrodes， which avoided the rapid solidification of liquid metal near the mold wall to generated slag ditchs when the slag bath temperature drops rapidly. The solidification quality and surface quality of hollow ingots were thus greatly improved. References | Related Articles | Metrics

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Purification of the Digestion Solution of Zinc Oxide Ores SHAO Hong-mei， SHEN Xiao-yi， ZHANG Bin-bin， ZHAI Yu-chun 2015, 36 (6):  811-814.  DOI: 10.12068/j.issn.1005-3026.2015.06.012 Abstract ( 723 )   HTML   PDF (454KB) ( 780 )   ZnSO4 solution was used as a raw material， which was obtained from zinc oxide ores roasted using (NH4)2SO4 and then digested in water. The main components in solution were ZnSO4， Fe2(SO4)3， Al2(SO4)3 and so on. NH4HCO3 was used as purifier reagent. Aiming to obtain refined ZnSO4 solution， the ammonium jarosite method and hydrolysis method were adopted to eliminate Fe3+ and Al3+ from the solution. The influences of pH values， the reaction temperature and time on the iron removal rate were discussed， and after the removal of iron， the ammonium jarosite slags were obtained. The pH value of solution was adjusted to precipitate Al3+ and Al(OH)3 was yielded out. The XRD， SEM and chemical components analysis were used to characterize the ammonium jarosite and Al(OH)3 slags. The results showed that the ammonium jarosite particles with regular shape growes well， and the size of Al(OH)3 slags is heterogeneous. References | Related Articles | Metrics

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Catalytic Effects of Surfactants on the Cobalt Ore Bioleaching LIU Wei， YANG Hong-ying， TONG Lin-lin， JIN Zhe-nan 2015, 36 (6):  814-818.  DOI: 10.12068/j.issn.1005-3026.2015.06.013 Abstract ( 695 )   HTML   PDF (603KB) ( 785 )   The effects of Tween-20， Tween-80 and RB-1181 surfactants on the bioleaching of cobalt ore were investigated. The results showed when the surfactant was employed， the contact angle between the solution and mineral was significantly decreased and the wetting action of the solution to the surface of ores increased. In addition， there were not negative effects on the growth of bacteria in the presence of appropriate concentrations of surfactants with the mass concentration of 0.25g/L， and the oxidation rates of ferrous ions were the same which were fully oxidized within 72hrs with or without surfactants. When surfactants were added， the surface properties of the intermediate product element sulfur were changed and the dispersion of surface passivation element sulfur was enhanced， thus the oxidation of element sulfur by bacteria was improved. As a result， the dissolution of the cobalt ore was accelerated， and the leaching efficiencies of metals were improved. In the presence of surfactants， the leaching efficiency of cobalt increased by approximately 34%， and that of copper increased by approximately 15% under the condition with ore pulp concentration of 10%， leaching temperature of 45℃ and the rotation rate of 180r/min. References | Related Articles | Metrics

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Electrochemical Corrosion Behaviors of 20Cr9Ni5Co14 Stainless Steels in NaCl Solution WEN Chen， XU Guang-xing， FAN Li-wei， CHEN Ya-zheng 2015, 36 (6):  819-823.  DOI: 10.12068/j.issn.1005-3026.2015.06.014 Abstract ( 741 )   HTML   PDF (538KB) ( 738 )   The corrosion behaviors of 20Cr9Ni5Co14 ultra high strength steel (USS) were studied by the electrochemical polarization methods (potentiodynamic polarization， linear polarization and cyclic polarization technologies) and alternating current impedance spectrum methods in different corrosion conditions， and after polarization the corrosion morphologies were characterized by Scanning Electron Microscopy(SEM). The results showed that the passivation phenomenon of 20Cr9Ni5Co14 steels appeared in 3.5wt.% NaCl solution while disappeared with the increase of NaCl concentration. The corrosion current also reduced from 8.223×10-7A/cm2 to 1.129×10-7A/cm2 with the increase of NaCl concentration. The passivation and transpassivation potentials of 20Cr9Ni5Co14 steels increased with the increase of hydrogen ion concentrations. When the pH value was higher than 3， the corrosion product film had excellent corrosion resistancewhich led the electrochemical polarization step as a dominated step， while the pH value decreased to 2， the corrosion products dissolution rate was fast， the corrosion rate of the interface of the metal surface and the solution was also fast， thus the polarization caused by concentration differences became the dominated step. Corrosion morphology studies showed that the corrosion of 20Cr9Ni5Co14 steels in the polarization process oriented from pitting corrosion， which leads to the reduction of corrosion resistance. References | Related Articles | Metrics

Mechanical Engineering

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Research on Fault Transfer Mechanism of Local Rub in Rotor System XU Qi， ZHAO Li-chao， ZHAO Qian， WEN Bang-chun 2015, 36 (6):  823-826.  DOI: 10.12068/j.issn.1005-3026.2015.06.015 Abstract ( 582 )   HTML   PDF (553KB) ( 775 )   The clearance between rotor and stator in rotating machinery becomes smaller to supply high speed and efficient. Local rub failure often occurs which can lead to nonlinear response in the whole rotor system. Timely obtained dynamic characteristics are vital to the fault in rub rotor system. Based on the finite element and the harmonic balance theory， the relationship between harmonic components of vibration responses and frequency response matrix was used to obtain local rub failure transfer mechanism. Validity and robustness were verified by numerical simulations and experiments. Responses of n+2 nodes were needed to obtain responses of the all remaining nodes in n malfunctions of rotor system. The transfer mechanism has a good applicability in rotor system aiming at the rub， misalignment， unbalance and crack. References | Related Articles | Metrics

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Analysis of Motion of the Part on the Linear Vibratory Conveyor KONG Xiang-xi ， XING Jin-xin， WEN Bang-chun 2015, 36 (6):  827-831.  DOI: 10.12068/j.issn.1005-3026.2015.06.016 Abstract ( 646 )   HTML   PDF (770KB) ( 948 )   Vibratory conveyor feeding part experiences discontinuous friction and collision， which is a typical strong-nonlinear dynamic problem. It is significant to obtain the motion state under different vibration conditions to design the vibratory conveyor. Based on Coulomb’s law and collision regime， the sliding-hopping motion model on a linear vibratory conveyor was established. The effects on the motion of the part were analyzed in different vibration conditions upon the proposed model. It was found that there were both forward and backward sliding in the hopping motion， which influenced the motion of the part. References | Related Articles | Metrics

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A Calibration Method on Base Excitation Amplitude of Piezoelectric Ceramic Exciter LI Hui， LIU Ying， WANG Yu， SUN Wei 2015, 36 (6):  832-837.  DOI: 10.12068/j.issn.1005-3026.2015.06.017 Abstract ( 575 )   HTML   PDF (659KB) ( 905 )   This paper researched how to accurately obtain base excitation amplitude of piezoelectric ceramic exciter (PCE) by some calibration methods. Firstly， a simple and reliable calibration method was proposed. The dynamics model of cantilever beam under base excitation of PCE was established to clarify calibration principle and simulate calibration process. Next， the calibration and test system of base excitation amplitude of PCE was set up. The key steps of this method were explained in details. At last， practicability and effectiveness of above calibration method were demonstrated by experiment. References | Related Articles | Metrics

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Research and Analysis on the Arc Length of the Rock Breaking Point on TBM’s Disc Cutter GONG Ya-dong， ZHAO Xiao-xu，CHENG Jun 2015, 36 (6):  838-842.  DOI: 10.12068/j.issn.1005-3026.2015.06.018 Abstract ( 702 )   HTML   PDF (663KB) ( 804 )   Based on its rock breaking movement in the full-face tunnel boring machine (TBM)， and the interaction between the disc cutter and the tunnel face being taken into account at the same time， a kinematics model of disc cutter was built by using coordinate transformation matrix method of space geometry and spatial kinematics. The three-dimensional figures of the theory crushed trajectory made by the disc cutter on the tunnel face and the arc length of the rock breaking point were obtained by using Matlab software. The simulation results show that the arc length on disc cutter decreases with the increasing of the cutter radius on cutter head， but the total arc length after cutter head rotating one circle increases linearly. The results are useful to research on tool wear and rock breaking mechanism， as well as to optimize the design and layout of disc cutters on the cutter head. References | Related Articles | Metrics

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Research on Dynamic Reliability and Failure Rate of Cemented Carbide Cutting Tool WANG Xin-gang， LYU Chun-mei， WANG Bao-yan， YAN Ming-ming 2015, 36 (6):  843-847.  DOI: 10.12068/j.issn.1005-3026.2015.06.019 Abstract ( 692 )   HTML   PDF (406KB) ( 829 )   Based on the main failure mode of cemented carbide cutting tool and the influence of impact loading times on cutting tool reliability， a mathematical model on dynamic reliability of cemented carbide cutting tool was built by using the theory of stress-strength interference model and stochastic process， and the change rule of reliability was also obtained. On this basis， with impact loading times and machining time as the metrics respectively， the failure rate models were established. The results show that cutting tool reliability decreases gradually with the increase of impact loading times and machining time， and cutting tool failure rate characteristics of “bathtub” curve. According to this curve， the earlier， random and wear-out failure period of cutting tool can be divided accurately， that provides a theoretical basis for tool selection test， repair time and reliability life. References | Related Articles | Metrics

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Genetic Algorithm-based Service Module Configuration Design of CNC Machine Tools SHENG Zhong-qi， XU Tao， XUAN Jia-yao， SONG Jun-you 2015, 36 (6):  848-852.  DOI: 10.12068/j.issn.1005-3026.2015.06.020 Abstract ( 622 )   HTML   PDF (698KB) ( 757 )   To realize the optimal design of the overall configuration of CNC machine tools， we use genetic algorithm to realize the configuration design of service module of CNC machine tools. According to the service type in product life cycle process， the service modules of CNC machine tools are classified into the product related service modules and the product unrelated service modules. We study the product unrelated service modules， using genetic algorithm to encode each service modules and using the service value coefficient， the service quality level and the customer satisfaction as the optimal object to establish the fitness function and set up the service modular multi-objective model of CNC machine tools. This algorithm can ensure the validity of the model through mutual constraint relationship between various service modules and submodules. Finally， the service module configuration scheme is solved by MATLAB. References | Related Articles | Metrics

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Research on Real-Time Control Strategies of Polishing Force ZHANG Lei， ZHOU Wan-song， LU Lei， FAN Cheng 2015, 36 (6):  853-857.  DOI: 10.12068/j.issn.1005-3026.2015.06.021 Abstract ( 629 )   HTML   PDF (869KB) ( 869 )   A force-position decoupling pneumatic servo control system for polishing force was set up to solve force-position coupling problem in traditional polishing process. The real-time control results of pneumatic control system for polishing force were researched by adopting traditional PID control， feed-forward PID control and single neuron PID control， using data acquisition card and RTW real-time toolbox in the Matlab/simulink. The parameters in feed-forward PID control can be identified by online recursive least squares algorithm. The weighting coefficients in single neuron PID control can be modified by the supervised Hebb learning rules. The real-time control experimental results of polishing force indicate that the better control effect can be realized by feed-forward PID control and single neuron PID control than by PID control. The duration for stabilizing process of the polishing force is short by feed-forward PID control and the oscillation is little during the stabilizing process of the polishing force by single neuron PID control. References | Related Articles | Metrics

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Dynamic Response of Honeycomb Sandwich Panel Under Impact Loading Based on Ansys LI Yong-qiang， HUAN Qiang 2015, 36 (6):  858-862.  DOI: 10.12068/j.issn.1005-3026.2015.06.022 Abstract ( 728 )   HTML   PDF (874KB) ( 756 )   For the aluminum honeycomb sandwich panel with SCSC edge supports， the dynamic response numerical calculations were conducted using the Ansys by considering the range and quantity of the filling particles in cell of honeycomb sandwich panel. The stress and strain of the honeycomb sandwich panel in different conditions were further compared. The result indicates that filling particles in the panel cell can well reduce the stress and strain and increase the energy absorption effect. When the range of filling particles is from 0.2 to 0.25 and the quantity of filling particles is 2， the stress and strain of honeycomb sandwich panel are minimal and the effect of the energy absorption is best. Too much filling particles do not have a better energy absorption effect but conversely can shock the honeycomb sandwich panel. References | Related Articles | Metrics

Resources & Civil Engineering

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Effect of Sulfurizing Agents on Speciation of Heavy Metals in Poultry Litter LIU Wen-gang， WEI De-zhou， GUO Hui-liang， YANG Pei-yue 2015, 36 (6):  863-867.  DOI: 10.12068/j.issn.1005-3026.2015.06.023 Abstract ( 622 )   HTML   PDF (722KB) ( 735 )   The five step sequential extraction procedure developed by Tessier was used to investigate speciation of the heavy metal(Zn， Cu， Mn， and Cr) in poultry litter when sodium sulfide and sodium diethyldithiocarbamate were added during shake flask test. And the immobilization effects of sulfuring agents on heavy metals had been explored. From the results， it can be seen that with the addition of sulfurizing agents， contents of heavy metals with exchangeable and bound to carbonate speciation in poultry litter were decreased obviously. Preferable immobilization effect can be achieved when sulfuring agent dosage was 2g/kg. Sodium diethyldithiocarbamate have better immobilization effect on four heavy metals than sodium sulfide. When sodium diethyldithiocarbamate was added， contents of heavy metals with exchangeable and bound to carbonate speciation were still decreased evidently in slightly acidic condition. However， better immobilization effect of heavy metals can be obtained in neutral or alkaline environment when sodium sulfide was used as immobilizing agent. Analytical chemistry and structural chemistry analysis demonstrated that， when sodium sulfide was used as immobilizing agent， precipitation reaction may occur between sulfur ion(or its hydrolysis product) and heavy metal ions. Nevertheless， sodium diethyldithiocarbamate can immobilize heavy metals by the formation of stable four-membered ring chelates. References | Related Articles | Metrics

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Disintegrating Efficiently of Excess Sludge by Combined Anaerobic Treatment and Ultrasonic Cavitation LI Xian-jin， YUAN Chun-li， YU Hong， ZHU Tong 2015, 36 (6):  868-872.  DOI: 10.12068/j.issn.1005-3026.2015.06.024 Abstract ( 696 )   HTML   PDF (563KB) ( 736 )   In order to improve the efficiency of disintegrating excess sludge and then to improve the performance of sludge biodegradability by using ultrasonic cavitation， a program of disintegrating excess sludge by ultrasonic cavitation after a short anaerobic treatment was proposed. In the experiment， excess sludge was treated 0~6days by anaerobic digestion and then disintegrated by ultrasonic cavitation. The results show as follows: with increasing of anaerobic digestion time， the properties of sludge change greatly， for example， the concentration of chemical oxygen demand(COD)and peptidogly can increase significantly， while the pH value drop observably. The efficiency of using ultrasonic cavitation method to disintegrate excess sludge after a process of anaerobic digestion is better than disintegrating excess sludge directly. For example， the result of disintegrating the excess sludge treated 6 days by anaerobic digestion shows that the concentration of COD is 99.3 times of the sludge without disintegrating， and 9.5 times of excess sludge without anaerobic digestion. This study considers that anaerobic digestion can reduce the difficulty of sludge disintegrating and the process of anaerobic digestion can significantly improve the intensity of ultrasonic cavitation to a large extent. Therefore， the process can achieve the aim of disintegrating the excess sludge efficiently. References | Related Articles | Metrics

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Automatic Generation of Coordinate Parameter Table of Roadway in AutoCAD Environment DING Hang-xing， REN Feng-yu， WANG Chun-xian， HAN Zhi-yong 2015, 36 (6):  872-875.  DOI: 10.12068/j.issn.1005-3026.2015.06.025 Abstract ( 583 )   HTML   PDF (439KB) ( 685 )   In the design of roadway drivage， the drawing of parameter table costs lots of time. If using the traditional method to draw the parameter table of roadway， the calculation and measurement are heavy work， and the precision is difficult to be guaranteed. By using the traditional method to analyze the coordinate parameters of roadway， it is found that the line length， Z coordinate calculation and azimuth measurement are complicated， thus an automatic calculation method in AutoCAD environment is proposed. Based on the above aspect and considering the convenience of the operation， FME program is compiled on the secondary development platform of AutoCAD VBA. Through the practical application in many mines， it shows that this program can generate the coordinate parameter table of roadway accurately and rapidly， which may greatly improve the efficiency of roadway design. References | Related Articles | Metrics

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Formula Development and Industrial Testing of a Hygroscopic Road Dust-Depressor DU Cui-feng， WANG Yuan， LU Jun-jie， WU Zhao-peng 2015, 36 (6):  876-881.  DOI: 10.12068/j.issn.1005-3026.2015.06.026 Abstract ( 503 )   HTML   PDF (553KB) ( 961 )   Based on the characteristics and mechanisms of open pit road dust， one hygroscopic road dust-depressor was developed. The components of the dust-depressor agent were optimized by taking water loss rate as the evaluation index， which is based on the orthogonal test. The hygroscopicity， wind resistance and other properties of the optimal formula were tested in a lab environment. The results showed that the moisture contents of the optimal formula were all above 8.18% within 25 days， indicating that the optimal formula had a very good windbreak performance. Taking the optimal formula to industrial testing， it was found that the effective time of dust suppression is 10 days. Compared with the traditional water spraying， it could reduce the cost for dust suppression by 30.71% and increase the water-saving efficiency up to 94.67%. References | Related Articles | Metrics

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Experimental and Modeling Study on the Rheological Properties of Tailings Backfill CAI Si-jing， HUANG Gang， WU Di ， ZHANG Ya-dong 2015, 36 (6):  882-886.  DOI: 10.12068/j.issn.1005-3026.2015.06.027 Abstract ( 740 )   HTML   PDF (642KB) ( 850 )   Taking backfill material for underground mine as the object of study， this paper aims to studying its rheological properties and strength characteristics by using the R/S+ rheometer and rock mechanics testing machine with the methods of experiment and theory analysis. And the visco-plastic fluid model of Papanastasiou was introduced to analyze the changing progress of viscosity and shear stress of tailings backfill. The results show that， the calculated results of this model were identical to the experimental results， thus it could be verified for theoretical calculation. In addition， the curve of shear stress-shearing rate at the different stress growth parameter was gotten， it is found that the viscosity and yields stress of backfilling develop with the increase of its mass concentration and the viscosity and yields stress of cementing tailings were higher than those of whole tailings at the same mass concentration. This study on rheological properties of tailings backfill are useful for designing filling station in mine. References | Related Articles | Metrics

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A New Semi-active Control Strategy of Highway Bridge Vibration MA Yong-quan， QIU Hong-xing， QI Yong-cheng 2015, 36 (6):  887-891.  DOI: 10.12068/j.issn.1005-3026.2015.06.028 Abstract ( 545 )   HTML   PDF (555KB) ( 697 )   To effectively suppress the oversize displacement of both grider and bearing on seismically isolated bridges after an earthquake， a new semi-active control strategy based on the force-feedback (FF) fit for magneto rheological dampers (MRD) was proposed. First， the semi-active control strategy taking the restoring force provided by seismic isolation devices as the main feedback signal was proposed. Then， the current criteria which were applied to help the damping force produced by MRD approximate to the desired control force were proposed. Finally， the semi-active closed-loop control system based on the force-feedback was designed. The various evaluation criteria of tri-span seimicically isolated continuous grider bridges with Passive-off control， Passive-on control， FF control and clipped optimal (CO) control were computed respectively. The results indicated that the control effects on girder displacement， bearing displacement and base shear under the FF control are more significant than those of Passive-on control， Passive-off control and CO control. References | Related Articles | Metrics

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Seismic Simulation and Analysis of the Two-Layer Prestressed Long-Span Subway Station TANG Xiao-wei， FU Pei-shuai， LI Hong， GONG Jian-fei 2015, 36 (6):  892-896.  DOI: 10.12068/j.issn.1005-3026.2015.06.029 Abstract ( 600 )   HTML   PDF (895KB) ( 840 )   To develop a two-layer prestressed long-span subway station， a nonlinear seismic numerical simulation of the soil-subway interaction system was conducted， applying the plastic-damage constitutive model to describe the nonlinear and fatigue characteristics of concrete under cyclic loading and taking into account the structural damping and initial stress of the soil-structure interaction system due to the gravity and prestress of reinforced concrete. The destruction process， destruction forms and destruction locations were analyzed after the simulation. The results indicated that the dynamic shear stress concentrates in the external bottom of side walls near to the baseboard， then the mid-span and the upper root of the top board and level board， which can spread fast and even form penetrated cracks in some parts. The dynamic tensile and compression damage emerges easily in the vertical direction of side walls near to the baseboard， and it also emerges easily in the horizontal direction of the top board and level board. The dynamic shear stress concentrates in turn in the junction between side walls and the top board as well as the baseboard. Side walls near to the baseboard and the root of the top board are key parts of a frame for safety where failure tends to occur earlier. References | Related Articles | Metrics

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Scenario Deduction Model of Unconventional Emergency Based on Dynamic Bayesian Network XIA Deng-you ， QIAN Xin-ming， DUAN Zai-peng 2015, 36 (6):  897-902.  DOI: 10.12068/j.issn.1005-3026.2015.06.030 Abstract ( 1019 )   HTML   PDF (739KB) ( 1222 )   The unclear evolution path and complex development of unconventional emergency could make it difficult for decision-makers to make right decisions. A model based on the dynamic Bayesian network was proposed to solve the key scenario deduction problems of unconventional emergency. In this model， the scenario evolution law of unconventional emergency was first analyzed to formulate the four factors including scenario situation(S)， disposal target (T)， disposal measure (M) and evolution (E). Then the scenario evolution path was performed based on the four factors. Finally， the state probabilities of corresponding node variables were calculated by using the joint probability formula. For the purpose of illustration and verification， the case of Dalian “7·16” oil depot fire and explosion accident was presented. The results showed that the evolution path follows oil pipeline explosion， oil tank explosion and fire， and oil spill and offshore pollution， whose probabilities are respectively 90.2%， 84.1% and 80.3%. Thus， it could be concluded that the proposed dynamic Bayesian network is both reasonable and feasible. References | Related Articles | Metrics

Management Science

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Multi-fractal Characteristics of the Rebar and Wire Rod Markets: an SHFE-based Empirical Study LI Yan， ZHUANG Xin-tian， YUAN Ying， TIAN Kun 2015, 36 (6):  903-908.  DOI: 10.12068/j.issn.1005-3026.2015.06.031 Abstract ( 603 )   HTML   PDF (464KB) ( 703 )   Based on the time series analysis， multi-fractal method and fractal rescaled range analysis (the R/S method)， an investigation on the time series of returns on the rebar and wire rod markets in China was done empirically. It was found that the time series of the returns on both steels are characterized by being leptokurtic and heavy-tailed， which are not normally distributed and show a long-term memory between prices， thus indicating that the rebar and wire rod markets don’t reach the soft efficiency. The efficient market hypothesis is thus to be queried. The scale variations of time series show that a single-scale index is insufficient to describe the price fluctuations of commodities. However， the multi-fractal analysis as a powerful instrument can serve to describe more accurately how the prices of rebar and wire rod vary. References | Related Articles | Metrics

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Case-based Fast Optimization Design for Complex Products FENG Guo-qi， CUI Dong-liang， MA Ming-xu 2015, 36 (6):  908-912.  DOI: 10.12068/j.issn.1005-3026.2015.06.032 Abstract ( 585 )   HTML   PDF (387KB) ( 747 )   Optimization design for complex products is of great difficulty because of its multidisciplinary characteristics. Multidisciplinary design optimization (MDO) can better deal with this issue， but there are still some flaws in implementing this technology. The exploration of the laws from previous cases can enhance the efficiency and quality of product design. Unlike the traditional methods of MDO， a fast design optimization is proposed from the perspective of knowledge application. Based on the key parameters extracted from design versions， the weights of vector are acquired by the calculation of the relationship between input parameters and output parameters. Rapid clustering is performed based on expert experience and design objectives， parameters are designed by the extension and re-sampling of cluster members， experiments are designed to provide high-quality initial solutions to the optimization designs with computational constraint， and the other samples from the same cluster are given knowledge-based evaluation and simulated with fast sampling optimization scheme. The results showed that this method is of great effectiveness and feasibility. References | Related Articles | Metrics