Journal of Northeastern University(Natural Science)

A New Network-on-Chip Topology and Its Adaptive Routing Algorithm

LI Zhen-ni， LI Jing-jiao， WANG Ai-xia， ZHANG Ren-shen

2017, 38 (9): 1217-1221. DOI: 10.12068/j.issn.1005-3026.2017.09.001

Abstract ( 969 )

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The topology and routing algorithm of network-on-chip (NoC) directly influence the transmission delay and transmission efficiency of the network. A new topology of NoC— H-annular Mesh was proposed based on the 2D-Mesh topology. The lines introduced from the vertex nodes to the center nodes constituted a half annular Mesh (H-annular Mesh)， which could fully take the advantage of 2D-Torus topology. An adaptive routing algorithm HAA-XY was proposed for H-annular Mesh topology. The simulation results indicate that based on the H-annular Mesh topology and the HAA-XY routing algorithm， the NoC can effectively reduce the network transmission delay， and can realize the multi-directional and multi-node data parallel communication.

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Research on Relay Power Allocation Algorithm for Cooperative Communication Systems

FAN Li-na， WANG Jin-kuan， GAO Jing， LYU La-mei

2017, 38 (9): 1222-1225. DOI: 10.12068/j.issn.1005-3026.2017.09.002

Abstract ( 851 )

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Power allocation of the cooperative communications was investigated， as well as an optimal power allocation of single relay system with amplify-and-forward (AF) protocol. The instantaneous symbol error rate (SER) for the AF relay system was derived first and the objective of optimization by minimizing the system error rate was defined. Secondly， the penalty factor was introduced to transform the constrained minimum bit error rate problem into an unconstrained problem and then a new objective function was established. Finally， a combination of artificial fish swarm and particle swarm optimization algorithm(AFPSO) was proposed to solve the system optimization problem. Simulation result shows that the proposed algorithm can improve the system performance and reduce the computational complexity.

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Recognition Method of Traditional Chinese Medicine Pulse Conditions Based on Extreme Learning Machine

CHEN Xing-chi， HUANG Shu-chun， ZHAO Hai， WANG Xiao-man

2017, 38 (9): 1226-1229. DOI: 10.12068/j.issn.1005-3026.2017.09.003

Abstract ( 836 )

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In the light of the ambiguity， variety， and complexity of traditional Chinese medicine(TCM) pulse conditions， and the shortcomings of traditional fuzzy cluster methods and backpropagation(BP) neural network methods， a novel method using the extreme learning machine(ELM) was proposed to detect the pulse conditions. This method identifies pulse condition by using the ELM to train and classify the characteristic vectors obtained by the pulse condition. The experimental results show that comparing with the traditional fuzzy cluster methods， BP neural network method and support vector machine method， the accuracy of proposed method is respectively increased by 21 percent， 9 percent and 5 percent， which shows that this is a better pulse condition estimation using proposed method.

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Correlation and Regression Analysis on the Parameters of Central Aortic and Brachial Pulse Waves

XU Li-sheng， CHAI Rui， YAO Yang， ZHANG Qian-qian

2017, 38 (9): 1230-1234. DOI: 10.12068/j.issn.1005-3026.2017.09.004

Abstract ( 796 )

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This study mainly analyzed the correlation of the parameters such as diastolic blood pressure (DBP)， systolic blood pressure (SBP)， pulse pressure (PP)， subendocardial viability ratio (SEVR)， waveform parameter (k)， stroke volume (SV)， cardiac output (CO) and peripheral resistance (R_S) of aortic pulse wave and brachial pulse wave invasively measured. Correlation analysis was performed on invasive central aortic parameters and brachial artery parameters of 40 patients who needed coronary arteriography. With the paired t-test and Bland-Altman method， these parameters extracted from the central pulse wave invasively measured were compared with the parameters of central aortic pulse wave caculated by a regression equation and a model. Results and conclusion: in addition to the k value， the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation; DBP and SEVR had the same consistency in the two estimation methods， and the regression equations of the two parameters were expressed by Y′=a+bx. The DBP， SBP， PP， SEVR， SV， CO also can be calculated by the regression equation， but its accuracy is worse than that of the transfer function model.

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Corrosion Behavior of Low-C Medium-Mn Steel for Offshore Platform Exposed to Seawater Environment

GAO Xiu-hua， ZHANG Da-zheng， SU Guan-qiao， DU Lin-xiu

2017, 38 (9): 1234-1238. DOI: 10.12068/j.issn.1005-3026.2017.09.005

Abstract ( 756 )

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The corrosion behavior of low-C medium-Mn steel in a simulated marine environment was investigated by drying-wetting cycles test. Scanning electron microscope (SEM) was used to characterize corrosion morphology. Electron probe micro-analyzer (EPMA) was utilized to observe the cross-section morphology and analyzed the distribution of Mn. X-ray diffraction (XRD) was employed to study the phase analysis of corrosion rust. The results showed that corrosion rate rises quickly at the beginning then decreases subsequently and finally tends to be stable. Corrosion products are gradually transformed into a dense and thick corrosion rust from the loose and porous morphology with the extension of the corrosion time. The main corrosion product in the high chloride ion environment is γ-FeOOH. In the meanwhile， there are many manganese oxides and iron-manganese oxides in the corrosion rust which were not found in other steels. Those corrosion phases can promote electrochemical reaction and accelerate the corrosion process.

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Size Effect in Copper Foil After Rolling

TANG De-lin， LIU Xiang-hua， SONG Meng

2017, 38 (9): 1239-1242. DOI: 10.12068/j.issn.1005-3026.2017.09.006`

Abstract ( 688 )

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The mechanical tests and EBSD (electron backscattered diffraction) analysis of industrially pure copper foil with thickness of 25~300 μm rolled by asymmetric rolling process had been conducted to study the size effect phenomenon. The size effect of copper foils with different thickness was found， i.e. the tensile strength and hardness first increased and then decreased with the decrease of foil thickness when the thickness reached the critical value. The mechanical property trended to change at the thickness threshold. The work hardening with the decrease of thickness only happened when the foil thickness was bigger than the thickness threshold. And when the foil thickness was less than the thickness threshold， work softening happened. The reason why size effect happened was that the grains were stretched， flattened even pulled off as the thickness of foil decreased so little new grains provided vast grain boundary which made the dislocation density decrease.

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Optimization of the Width Adaption Model in Hot Tandem Rolling

PENG Wen， CHEN Qing-an， MA Geng-sheng， ZHANG Dian-hua

2017, 38 (9): 1243-1246. DOI: 10.12068/j.issn.1005-3026.2017.09.007

Abstract ( 728 )

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In order to improve the width control precision in rough rolling process， an adaption method for optimizing parameters of the width spread model was proposed. The natural width spread coefficient and the dog-bone width spread coefficient in the width model were taken as the adaption parameter vectors， and the width adaption model objective function was founded based on the vectors. The Nelder-Mead method was used to search the optimal solution of the objective function， and the optimized parameters vectors were obtained which fulfilled the model precision of the width control process. The results showed that the adaptive method is successfully applied to the control system of one 850mm hot tandem mill. Compared with the traditional method， the width deviation between the actual measured ones and the predicted ones is reduced from 3.05mm to 1.28mm with the proposed method. The validity and precision of the proposed adaption model are verified， and the width quality is enhanced greatly.

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Simulation of Deformation Zone Temperature for AZ31 in Warm Rolling Process

YANG Hong， LI Jian-ping， XU Zheng， SUN Tao

2017, 38 (9): 1247-1250. DOI: 10.12068/j.issn.1005-3026.2017.09.008

Abstract ( 667 )

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There are many factors that cause fluctuations of the deformation zone temperature in warm rolling process of AZ31 magnesium alloy strip. Therefore， the accurate prediction of the deformation zone temperature is the key to guarantee the product quality in warm rolling process. The deformation zone temperature of AZ31 magnesium alloy in warm rolling process was simulated by using finite element method . The physical parameters of rollers and strips were given together with the initial and boundary conditions of simulation. The results demonstrated that the five key factors affecting deformation zone temperature are identified as roller temperature， rolled-piece temperature， rolled-piece thickness， rolling speed and reduction ratio. The simulation data were obtained by orthogonal experimental simulation method， the regression model of the deformation zone temperature was gotten. Finally the mathematical model accuracy was detected through a group of simulation data.

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Effects of Welding Speed on Microstructure and Properties of Laser Welded Joints of Dual-Phase Steel

DONG Dan-yang， JIANG Di， YANG Run-chen

2017, 38 (9): 1251-1256. DOI: 10.12068/j.issn.1005-3026.2017.09.009

Abstract ( 917 )

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In order to improve the service reliability of the welded component for auto-body under the dynamic load， the effects of laser welding speed on the microstructure and tensile properties at various strain rates of the pulsed laser welded joints of 1.4mm thick DP780 steel were studied. The results showed that the DP780 welded joints exhibit the hardening in the fusion zone and the softening in the outer heat-affected zone under various welding speeds. The softening degree of the welded joints decreases with increasing welding speed. The strength of the welded joints increases with increasing strain rate， and the ultimate tensile strength and fracture elongation increase first and then decrease with increasing welding speed. The welded joints with good surface morphology， moderate weld width and penetration， no weld defect are fabricated when the welding speed is 400mm/min. And the softening degree of the outer heat-affected zone is the lowest with the softening fraction of 9% and the hardness in the fusion zone is moderate. The overall strength and ductility of the DP780 welded joint reach an optimum value under the welding speed of 400mm/min.

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Thermal Analysis and Kinetics of La_0.8Sr_0.2(Ga_0.8Mg_0.2)_1-○xFe_○xO_3-○δ○Mixed Conductor

ZHANG Xiao-fang， LIU Tao， YU Jing-kun， GAO Xiang

2017, 38 (9): 1257-1262. DOI: 10.12068/j.issn.1005-3026.2017.09.010

Abstract ( 704 )

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The mixed conductor La_0.8Sr_0.2(Ga_0.8Mg_0.2)_1-○xFe_○xO_3-○δ (LSGMF) samples were prepared by solid-state reaction. The performances were researched by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The influence of doped Fe content on the thermal weight loss process and kinetics of LSGMF was investigated， and the apparent activation energy for the process was calculated with the Coats-Redfem method. The results showed that the thermal weight loss process of LSGMF can be divided into three stages. In the low-temperature region， the thermal weight loss is mainly caused by desorption of H₂O and CO₂ adsorbed on the surface of LSGMF， and the apparent activation energy is 0.154~0.227eV. In the medium and high temperature region， it mainly attributes to some of the lattice oxygen atoms becoming O₂， and the apparent activation energy is 0.280~0.350eV. When the doped Fe content x is 0.9， the peak value of weight loss rate is the smallest (0.0137/s)， and the apparent activation energy E_○2+3 is the highest. It indicates that the weight loss rate is the slowest and the stability of LSGMF is the highest.

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Effect of Slot Rough Wall on Transfer Behavior of Particle-Gas Flow in the Device of Ladle Bottom Powder Injection

CHENG Zhong-fu， ZHU Miao-yong

2017, 38 (9): 1262-1267. DOI: 10.12068/j.issn.1005-3026.2017.09.011

Abstract ( 646 )

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For the new technology of ladle bottom powder injection， the effect of rough slot wall on transfer behavior of particle-gas flow was studied. A new probability distribution function of roughness angle was proposed by analyzing the process of particle-rough wall collision， and a particle history effect model was established to consider wall roughness effect. Based on the Eulerian-Lagrangian approach， this model was utilized to stochastically model the transfer behavior of particulate flow in the slot plug. The effect of wall roughness on particle trajectories， velocity distributions and particle mass concentrations was considered， and the trajectories of particles near the slot wall have been predicted successfully. The results indicate that roughness wall causes particles to collide on the wall with a higher frequency， which leads to the decrease of particle kinetics and the increase of fluctuation velocity. Moreover， roughness wall also causes a more uniform distribution of particles in the bottom powder injection device.

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Numerical Simulation of Flow，Heat Transfer and Mass Transfer for Stagnation Point MHD Layer Flow

TIAN Xi-yan， LIU Yu-qiang， LEI Hong， LI Ben-wen

2017, 38 (9): 1268-1273. DOI: 10.12068/j.issn.1005-3026.2017.09.012

Abstract ( 618 )

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When a heated infinite permeable flat plate made of porous media lays horizontally in a steady magnetic field and an electrically conducting fluid with lower temperature flows vertically towards the plate， a thin boundary layer can be formed in the vicinity of the stagnation point over the plate. The fluid flow， heat transfer and mass transfer within this boundary layer were investigated numerically and the radiation effect was studied. After using the Rosseland approximation to describe the radiative heat flux， the constitutive equations can be solved by the collocation spectral method (CSM)in the domain discretization. The effects of suction/injection parameter(f_W)， magnetic parameter(M)，radiation parameter (R)and convection heat transfer parameter on the flow in the boundary layer， heat transfer， mass transfer， skin friction coefficient， Nusselt number and Sherwood number were discussed.The results indicate that with the increasing of f_W and M， the flow boundary layer becomes thicker， while the thermal boundary layer becomes thicker with the increasing of R.

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Study on Heat Transfer of Pre-prepared Pellets for Mg-Extraction by Silicothermic Process

FU Da-xue， GUAN Lu-kui， DOU Zhi-he， ZHANG Ting-an

2017, 38 (9): 1274-1279. DOI: 10.12068/j.issn.1005-3026.2017.09.013

Abstract ( 742 )

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A novel method of feed preparation for silicothermic process was proposed to overcome the shortages in Pidgeon process. In this method， dolomite， ferrosilicon， fluorite and binder are mixed to produce pellets and then calcined. Thereafter， the pre-prepared pellets are charged into the retorts immediately. Heat transfer of the pellets was investigated by the steady-state-flat method and numerical method. The results show that thermal conductivity of the pellets increases with the increasing temperature， conversely with the pellet density and the amount of Si-Fe addition. For the sample pellet with the density of 1.1g/cm³ and the theoretical amount of Si-Fe， the relationship between thermal conductivity and temperature can be expressed as λ=1.04×10^-4T+0.11. Heat transfer of a spherical pellet is better than a cylindrical one. The better heat transfer from pellet surface to pellet center can be obtained for a pellet with less density， less specific heat capacity and larger thermal conductivity. The mode/mechanism/principle of heat transfer of the pre-prepared pellets is similar to the pellets used in Pidgeon process.

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Preparation of Flake-Like Magnesium Hydroxide by Diaphragm Electrodeposition Method and Its Influence Factors

DENG Xin-zhong， DI Yue-zhong， WANG Yao-wu， FENG Nai-xiang

2017, 38 (9): 1280-1284. DOI: 10.12068/j.issn.1005-3026.2017.09.014

Abstract ( 622 )

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Flake-like magnesium hydroxide was prepared by the diaphragm electrodeposition method using magnesium chloride hexahydrate (MgCl₂·6H₂O) as raw material. The effects of processing parameters， such as the concentration of Mg²⁺， reaction temperature and the electric current density，on the morphology and particle size of magnesium hydroxide were investigated. The morphology and particle size of the produced magnesium hydroxide (Mg(OH)₂) particles were characterized by scanning electron microscopy (SEM) and laser particles distribution instrument， respectively. The results indicate that the products from this method have higher rate of settlement and easily segregates. When the initial concentration of Mg²⁺ increases， the particle size increases and the flaky morphology is bigger and thicker. With the increasing reaction temperature， the flaky morphology defects become greater and particle agglomeration is more serious， while the particle size decreases firstly and then increases. As the current density increases， the particle size decreases. Meanwhile， the flake features are degraded and eventually dendritic morphology appears. The specific surface area of these samples can be detected by the brunauer emmett teller (BET) method with a maximum value of 82.36m²/g and its adsorption capacity of methyl violet (MV) can reach 1256mg/g.

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Novel Hydrometallurgical Process of Refractory Copper-Cobalt Ores from Zambia

LIU Yuan-yuan， YANG Hong-ying， TONG Lin-lin， JIN Zhe-nan

2017, 38 (9): 1285-1288. DOI: 10.12068/j.issn.1005-3026.2017.09.015

Abstract ( 742 )

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The features of low grade refractory copper-cobalt ores from Zambia were investigated and a novel hydrometallurgical process for them was provided. The results show that the contents of Cu， Co and S in the ores are 1.270%， 0.071% and 0.022%， respectively.Copper element is mainly in the pseudomalachite ore， while only a small amount is in the malachite. Cobalt element is mainly in the cobalt-manganese and heterogenite ores. There are also a small amount of copper and cobalt found in the limonite ore and biotite crystals. Therefore，the presence of copper and cobalt elements in the ore is very complex. In the process ，the optimum leaching conditions are as follows: the ore particles less than 74μm are 70%， the temperature is 65℃， the leaching time is 4h， the pulp density is 30%， and the amount of sulphuric acid is 55kg·t^-1 ore. Under such conditions， the leaching rate of copper and cobalt can reach about 74.34% and 43.32%， respectively.The sulfuric acid consumption can be reduced more than 20% by the replacement of the raffinate. The addition of the reducing agent Na₂SO₃ or FeSO₄ can increase the cobalt leaching rate from 43% to 78%.

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Preparation of New Chitosan/Diatomite Composite Materials and Their Adsorption Effect on Mercury Ions

HU Jian-she， ZHANG Hao-lin， TIAN You-liang， LIU Ke-li

2017, 38 (9): 1289-1292. DOI: 10.12068/j.issn.1005-3026.2017.09.016

Abstract ( 662 )

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A new polymer composite adsorption material of diatomite and chitosan was prepared using a crosslinking agent of glutaraldehyde and its adsorption property of mercury ions (Hg²⁺) in water was studied. The effects of the composite material ratio， initial concentration of Hg²⁺， the weight of adsorption material and adsorption time on the Hg²⁺ removal property were investigated. The results show that the Hg²⁺ removal rate and adsorption capacity decrease with the increasing diatomite content in the composite. However， the Hg²⁺ removal rate decreases and adsorption capacity increases with the increasing initial concentration of Hg²⁺. The Hg²⁺ removal rate and adsorption capacity increases with the increasing weight of the adsorption material. When the adsorption time is less than 45min， the corresponding Hg²⁺ removal rate and adsorption capacity increases with increasing adsorption time， while they become nearly constant after 45min.

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Analysis for Crossing Obstacle Distance of Dual-Arms Inspection Robot

WEI Yong-le ， FANG Li-jin， TAO Guang-hong

2017, 38 (9): 1293-1297. DOI: 10.12068/j.issn.1005-3026.2017.09.017

Abstract ( 825 )

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The crossing obstacle distance of three type dual-arms inspection robots， including arms fixed robot， arms mobile robot and robot with flexible cable， was investigated. The mathematical models were established for the crossing obstacle distance of the three type dual-arms inspection robots by theoretical analysis. Under similar values of the quality and dimensions， the max crossing obstacle distance of the three type robots were calculated based on the different gradients of the transmission line. The results show that the arm movements of dual-arms inspection robot with flexible cable are more flexible with a larger crossing obstacle distance， which can be regulated by the obstacle size. Thus， the dual-arms inspection robot with flexible cable has obvious advantages in realizing lightweight structure design.

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Modal Testing Experiment Based on Simulation Impeller of Turbine

PAN Hong-gang， YUAN Hui-qun， ZHAO Tian-yu， WANG Guang-ding

2017, 38 (9): 1298-1303. DOI: 10.12068/j.issn.1005-3026.2017.09.018

Abstract ( 978 )

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To solve the problem of turbine stator rub and even serious accident arising from the excitation resonance， frequency modulation excitation of a simulated turbine impeller was carried out based on the resonance principle. An experimental analytic approach is presented by arranging fine sand on impeller to simulate the vibration mode of impeller. Comparing with the finite element calculation， the results show that this experimental method can intuitively and accurately reflect the vibration of simulated turbine impeller. It may provide technical support and experiment basis for the vibration characteristic analysis and manufacturing process of the roulette system.

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Effect of Brake Pressure on High Frequency Braking Squeal of Disc Brakes

GAO Pu， WU Yun-hao

2017, 38 (9): 1303-1308. DOI: 10.12068/j.issn.1005-3026.2017.09.019

Abstract ( 647 )

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Based on the closed-loop coupling modal of disc brake structures， an optimal method and static loaded modal test were used to extract the actual contact coupling stiffness with different brake pressures applied， and the connection between the brake pressures in the actual conditions and the contact coupling stiffness in the parametric model was established. Subsequently， the sensitivity analysis method was used to explore the effect of the contact coupling stiffness on the unstable tendency of the brake system. Finally， according to the corresponding relationship of brake pressures and contact coupling stiffness， the effect of contact coupling stiffness on the unstable tendency was transformed into the impact of the brake pressure on the high frequency braking squeal. The sensitive range of the brake pressure making the system tend to be unstable could be obtained， which is helpful to put forward the active control measures to suppress the high frequency braking squeal.

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ABAQUS User Subroutine Development for Energy Releasing Rate of the Functionally Graded Plate with Cracks

ZHOU Li-ming， REN Shu-hui， MENG Guang-wei， LI Rong-jia

2017, 38 (9): 1309-1314. DOI: 10.12068/j.issn.1005-3026.2017.09.020

Abstract ( 913 )

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To obtain the dynamic energy releasing rate of the functionally graded plate with cracks， a virtual crack closure technique was proposed based on the inhomogeneous finite element method. A fracture dummy node element of the functionally graded material under dynamic loading was developed， user-defined subroutines named UMAT and UEL were programmed， and the component of energy releasing rate for the functionally graded plate caused by dynamic loading was calculated based on the finite element software ABAQUS platform. For the different shape factors such as the center-crack and inclined-crack inside the functionally graded plates， the component of the dynamic energy releasing rate was solved， and then it was transformed into the dynamic stress intensity factor， which was used for comparing the results calculated by the finite difference method. The numerical calculating results showed that the dummy node element of the functionally graded material fracture caused by dynamic loading is characterized by high precision， simplicity and convenience without using the singular element or special element for the crack tip and the versatility of its subroutines， which may provide a new approach for the engineers to get the dynamic fracture parameters.

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Production System Maintenance Decision Models Based on Product Quality and Rework Process

ZHOU Bing-hai， LIU Yu-wang

2017, 38 (9): 1315-1321. DOI: 10.12068/j.issn.1005-3026.2017.09.021

Abstract ( 625 )

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To effectively reduce the operation cost and ensure the throughput of production systems simultaneously， a preventive maintenance decision model was proposed， taking into consideration the product quality and rework process. Firstly， based on the location of the rework point， the whole production line was divided into two parts. Under this condition， the throughput evaluation and preventive maintenance models were established for the purpose of maximizing the overall revenue of the systems at the pre-and post-rework points， by using the decomposition method and the state transition rule respectively. Finally， an example analysis of the model was given by using the estimation algorithm of hybrid particle swarm distribution and the results showed that the proposed model and algorithm are valid and workable.

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Immobilization Property of Sodium Diethyl Dithiocarbamate on Cr³⁺ and Ni²⁺ in Soil

LIU Wen-gang， ZHAO Liang， WEI De-zhou， ZHANG Rui-yang

2017, 38 (9): 1322-1326. DOI: 10.12068/j.issn.1005-3026.2017.09.022

Abstract ( 775 )

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Immobilization property of sodium diethyl dithiocarbamate (DDTCNa) on Cr³⁺ and Ni²⁺ in polluted soil was investigated by column leaching process. Experimental results indicated that good immobilization effect of heavy metals in polluted soil was obtained when DDTCNa was used. Especially， DDTCNa showed better immobilization effect on Cr³⁺. Immobilization rate of heavy metal increased with the increase of DDTCNa dosage. When DDTCNa dosage was 110g·kg^-1， more than 99% of Cr³⁺ and Ni²⁺ can be immobilized. Additionally， leaching pH had some effect on immobilization of Cr³⁺ and Ni²⁺. With the reducing of leaching pH， immobilization effect of Cr³⁺ and Ni²⁺ decreased. However， high immobilization rate of Cr³⁺ and Ni²⁺， which were more than 90%， could also be obtained. And immobilization rate of Cr³⁺， which was higher than 99.68%， decreased slightly with the reduction of leaching pH. The formation of metal sulfide chelating precipitates and the immobilization mechanism were systematically studied by XRD measurements and coordination chemistry analysis. The results showed that four-membered chelating precipitates with the coordination number of 4 and 6， respectively， which were Ni(DDTC)₂ and Cr(DDTC)₃， could be obtained when DDTCNa reacted with the heavy metals. Moreover， the stability of Cr(DDTC)₃ was much better than Ni(DDTC)₂， so better immobilization property of Cr³⁺ was obtained.

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Application of the Multi-stage Contact Oxidation Method in Automobile Painting Wastewater Treatment

ZHU Yu-fang， ZHU Tong， Udo Fienko， MA Yong-guang

2017, 38 (9): 1326-1330. DOI: 10.12068/j.issn.1005-3026.2017.09.023

Abstract ( 753 )

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A multi-stage contact oxidation system was used in a bench-scale experiment study to treat the automobile painting wastewater， which has poor biodegradability and contains high concentration of COD (chemical oxygen demand). The wastewater used for this experiment is the actual painting wastewater which has been pretreated by the physic-chemical treatment process in the paint shop of some automobile factory， and its BOD₅/COD is less than 0.1， COD mass concentration is 800~1500mg/L. The results shown that the multi-stage contact oxidation system can efficiently degrade the COD of the painting wastewater. After the experimental system keeping running stably， the total COD removal rate is more than 80% with the hydraulic retention time (HRT) of 8 hours. Meanwhile， this system has a strong impact resistance capacity. The COD mass concentration of final treated wastewater is less than 500mg/L， which can reach the factory discharge requirement for the paint shop. Besides， this system with simple structure can efficiently reduce the excess sludge production and can keep running stably， which can greatly reduce the treatment cost for the painting wastewater.

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Study on the Stress Relaxation of Sandstone with Different Moisture Contents Caused by Dynamic Distrubance

LI Shuai， ZHU Wan-cheng， YU Yong-jun， ZHAO Long

2017, 38 (9): 1330-1334. DOI: 10.12068/j.issn.1005-3026.2017.09.024

Abstract ( 629 )

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Axial stress and strain of sandstone with different moisture content were measured by self-designed stress relaxation-dynamic disturbance testing apparatus. It is showed that there exists stress decline and strain increase after the dynamic disturbance was applied on the sandstone specimen. Effects of moisture content on the stress relaxation magnitude and level were analyzed. According to the constitutive law of rock subjected to accumulated deformation disturbance， the disturbance factors range from 2 to 6 at different moisture content conditions.The results show that ①During the stress relaxation process， the magnitude and level of stress relaxation at different time are increased due to the effect of water.The stress reduction can be enhanced by water. ②Under the same impact energy， both the strain increase and stress decrease are observed in sandstone specimen under higher moisture level. The disturbance factor increases with the increase of moisture content.

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Determination of West Boundary for Landslide Body of the South Slope in an Open-Pit Mine

ZHANG Fei， YANG Tian-hong， WANG Zhi， XIAO Ping

2017, 38 (9): 1335-1340. DOI: 10.12068/j.issn.1005-3026.2017.09.025

Abstract ( 579 )

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Aiming at a landslide appeared during the creep deformation in the south slope of an open-pit mine， the surface morphology of the west boundary of the landslide was determined by using the on-site measurement and the INSAR technique when the east and south boundary shape were already known. Meanwhile， the underground sliding surface was determined by micro-seismic monitoring technique and the west boundary shape was determined according to the surface morphology and the underground sliding surface. Both the geological horizons in the main researching area and the bottom sliding surface of the landslide body were established by the 3D modeling technique. The west boundary shape provides a theoretical basis for the following determination of the landslide shape in the south slope. This collaborative monitoring programme can be a reference for mine slope monitoring under the similar condition.

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3-D Grid Generation Method for Reservoir Numerical Simulation

CAO Kai， PAN Mao， SUN Peng， ZHANG Hui

2017, 38 (9): 1341-1346. DOI: 10.12068/j.issn.1005-3026.2017.09.026

Abstract ( 596 )

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Because the application of unstructured grid is still need to be improved， a hexahedral-gridding method was designed in order to overcome limitations of the Pillar Grid when simulating complex faults and its non-orthogonality.The grid model is regular in XY direction and the discontinuous surface is presented as a stair-step style. First， a structural model is built， including faults and stratum; Secondly， the topological information and geometric elements of the structural model is extracted so as to build macroscopic topology model based on G-maps; Finally， a method of discretizing the geological surfaces into lots of tangent planes is used to generate grids. Cases have proved that the methods above are accurate and effective to generate the desired grid model.

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Influence of Temperature on the Mechanical and Deformation Properties of Containing-Gas Raw Coal Under Mining

LIAO Xue-jiao， JIANG Chang-bao， DUAN Min-ke， TIAN Wei-jun

2017, 38 (9): 1347-1352. DOI: 10.12068/j.issn.1005-3026.2017.09.027

Abstract ( 633 )

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Taking raw coal as object， by using self-made “thermal-hydro-mechanical coupled with triaxial servo-controlled seepage apparatus for containing-gas coal”， the effect of temperature on the mechanical properties of containing-gas raw coal was studied under constant confining pressure and unloading confining pressure. The results showed that: 1) Under the same initial confining pressure， gas pressure and temperature， compared with the constant confining pressure， the yield stage of the coal under unloading confining pressure is shortened. Besides， its peak stress and associated axial strain decrease， the transverse strain rate increases， and the evolution processes of its lateral expansion ratio and deformation modulus are accelerated. 2) Under the same initial confining pressure and gas pressure， with the increase of temperature， the strength of coal under unloading confining pressure decreases， the axial strain at peak stress， the absolute value of the transverse strain and volumetric strain decrease， and the lateral expansion ratio and the deformation modulus increase. 3) The risk of coal unstable failure and coal and gas outburst becomes higher under high temperature environment， leading to more strict requirements for the support of coal face roadway and the control of coal and gas outburst.

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Influence of Karst Cavern on Mechanical Behavior of Tunnel Lining Structure

WANG Wei， ZHANG Heng-wen， ZHAO Dong， ZHANG Xue-min

2017, 38 (9): 1353-1357. DOI: 10.12068/j.issn.1005-3026.2017.09.028

Abstract ( 605 )

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Based on the Pasternak elastic foundation beam theory considering the shear deformation， the displacement and the internal force calculation formulas of the beam for non-inverted tunnel arch foot were derived. Calculation results of Pasternak model and Winkler model and field monitoring results were contrasted. Based on the Pasternak model， the deformation and stress states of lining under different compression modulus ratio of cavern media and different cavern scales were comparatively analyzed. The results show that Pasternak′s solution is smaller than that of Winkler model and agrees with the field monitoring results. The inflection point of lining is located at the junction between cavern and the surrounding rockmass， where the maximum shear force can be observed. When the ratio of compression modulus of the infillings to the surrounding rockmass is less than or equal to 0.5， the displacement and internal force of the lining increase rapidly. The cavern scale has an obvious influence on the displacement and shear stress and the lining in the karst cavern with a length of over 8 m is easily destroyed.

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Analysis of Transnational Licensing Selection and Social Welfare

HOU Ze-min， QI Yong， WANG Chun-bo， XIANG Tao

2017, 38 (9): 1358-1362. DOI: 10.12068/j.issn.1005-3026.2017.09.029

Abstract ( 801 )

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A model was set up based on Cournot quantity competition between foreign firms and local firms in considering import taxes. Through this model， the effect of the fixed-fee， royalty and two-part tariff licensing modes on the profit of foreign firms and the social welfare of import countries was analyzed to explain the mechanism of technological licensing in the transnational context. The research showed that the fixed-fee mode may make the profit of foreign firms uncertain and damage the social welfare of import countries. Royalty mode can increase the profit of foreign firms while it may decrease the social welfare under certain conditions. The two-part tariff mode can increase the profit of foreign firms and the social welfare， which realizes both the corporate and social goals. Morover， the two-part tariff mode may be specialized into the fixed-fee mode when the import tax is comparably high.

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Choice of Retailing Channels Based on Parallel Imports

SU Hui-qing， LI Kai， HUANG Wei

2017, 38 (9): 1363-1368. DOI: 10.12068/j.issn.1005-3026.2017.09.030

Abstract ( 540 )

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Channel selection strategies of manufacturers were studied from the perspective of parallel imports(PI). The Stackelberg game models were built under the single channel with authorized imports， and expanded to the double channel with an aim to exploring the effect of parallel imports on licensed production. Based on this， the impact of parallel imports on the channel selection of manufacturers(owners of intellectual property rights) and the consumer welfare were considered. The results showed that manufacturers’ channel selection strategies are influenced by parallel import cost， demand elasticity and production cost. When the demand elasticity differentiation is large， the profit of manufacturers with the single channel is higher regardless of the parallel imports. The manufactures are more likely to choose the double channel while the demand elasticity differentiation between the two countries is declining. In addition， the parallel imports improve the consumer welfare of the PI-recipient market.

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