Journal of Northeastern University(Natural Science)

Fuzzy H_∞ Controllers Design Approach for Steam Valve Opening of Multi-machine Power Systems with Mixed Time-Varying Delays

LIU Xin-rui， YANG Dong-sheng， LIU Shuang， HOU Xin-ming

2016, 37 (6): 761-765. DOI: 10.12068/j.issn.1005-3026.2016.06.001

Abstract ( 615 )

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The fuzzy H_○∞ controller design problem was studied for steam valve opening of multi-machine power systems which consisting of turbo-generators with mixed time-varying delays. The mixed time-varying delays include the interval retarded-type discrete delay， the neutral-type discrete delay and the time-varying distributed delays. Fuzzy models were established， and the controllers of the systems were designed. Linear matrix inequalities (LMIs)-based H_○∞ stability conditions were derived. Moreover， the results were expanded to different conditions of time-delay， including H_∞ stability condition with the fast time-varying distributed delays (i.e. the derivatives of distributed delay is larger than 1). Therefore， the obtained results are new and less conservative. Finally， simulation results for the steam value opening of three-machine infinite bus systems were provided to verify the effectiveness of the proposed results.

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Fault Diagnosis of Power System Based on Model-based Diagnosis and Skyline Query

JIANG Xue-chen， WANG Da-zhi， NING Yi， LIU Xiao-qin

2016, 37 (6): 765-769. DOI: 10.12068/j.issn.1005-3026.2016.06.002

Abstract ( 598 )

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The expert system used in power system fault diagnosis has a long development cycle and can not diagnose the faults beyond experiences. A kind of fault diagnosis of power system was proposed based on model-based diagnosis and skyline query. The diagnosed system was decomposed into several independent subsystems based on the distribution of measurement points. By establishing system models considering the causality between the system failure output and system element， candidate diagnosis of each subsystem was inferred. The actual alarm information was introduced into diagnosis logic framework to identify the fault element from candidate diagnosis by using skyline query. Ready candidate diagnosis was obtained offline and candidate diagnostic was confirmed online based on the proposed method， which saved the time of diagnosis. Actual alarm information was introduced into diagnosis logic framework， which improved the efficiency of diagnosis. The simulation results show that the method can effectively reduce the complexity of time and space.

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Object Detecting and Tracking Algorithm Based on Optical Flow

XIAO Jun， ZHU Shi-peng， HUANG Hang， XIE Ya-nan

2016, 37 (6): 770-774. DOI: 10.12068/j.issn.1005-3026.2016.06.003

Abstract ( 2104 )

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Harris corner points were adopted as tracking objects， and scale space was introduced into corner point detection in order to extract Harris corner points in feature scale. Then curvature was computed to filter out false corners and enhance adaptability to scale change. Optical flow method was adopted for the tracking algorithm based on image pyramid， in which the optical flow iteratively was computed. And the tracking algorithm based on the optical flow error was proposed. That is， the trajectory error in the same frame with different time flow was used to evaluate the tracking situation. In this way， tracking failure was avoided when the tracking object is hidden， disappears or textural features change. Experimental results of different video sequences show that the proposed optical flow tracking algorithm based on improved corner extraction and image pyramid has better tracking performances. The feature points could be filtered effectively that lead to tracking failure with the introduction of optical flow error method， and the object positions are estimated accurately.

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Users’ Web Browsing Behavior Prediction Model Based on Markov Model and Bayesian Theorem

BI Meng， HOU Lin， NI Pan， ZHOU Fu-cai

2016, 37 (6): 775-780. DOI: 10.12068/j.issn.1005-3026.2016.06.004

Abstract ( 727 )

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According to the novel aspect of natural hierarchical property of Web site， the inverted index structure was proposed based on Hash table (IIS-HT) to promote the speed of data preprocessing. Based on IIS-HT， a prediction model was also proposed which was based on statistics to predict users’ browsing behavior. The design idea， definition， framework and key construction methods of the model were also given. Finally， the proposed model was tested with real data. The experimental results show that the model and prediction algorithm could reduce the scope of candidate pages and improve the speed of prediction with adequate accuracy.

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Economic Model of BitTorrent Network Based on Tit-for-Tat

LIU Yan-heng， YI Ze-zhong， WANG Ai-min， LI Song-jiang

2016, 37 (6): 780-784. DOI: 10.12068/j.issn.1005-3026.2016.06.005

Abstract ( 754 )

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To solve the problem that the free-riding behavior of a node will seriously affect the download progress of the common node and the whole network performance in the BT network， a new economic model (TTEM) was proposed based on the tit-for-tat mechanism. According to the commodity trading and credit system in the social life， the economic model was presented that consisted of the node wealth， the file blocks pricing and the node overdraft. Finally， the TTEM was proposed by deploying the economic model on the tit-for-tat. Resources spread between nodes as a transaction in TTEM. Nodes were traded by the price of the file blocks， making the wealth of the node change， if the node’s wealth is greater than the overdraft. The simulation results show TTEM is able to reduce the impact which the free-rider nodes make on the BT network than the pure tit-for-tat mechanism under the similar propagation velocity of the file resources.

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Laser Transformation Hardening Process and Microstructure and Properties of 780 MPa Grade Micro-alloy Steel

SUN Qian， DI Hong-shuang， LI Jun-chen

2016, 37 (6): 785-789. DOI: 10.12068/j.issn.1005-3026.2016.06.006

Abstract ( 637 )

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A Nb-Ti-Mo micro-alloyed ultra-high strength hot-rolled low carbon steel was treated by laser induced phase transformation hardening process， using IPG 4kW fiber laser. The effects of laser power and scanning speed on macroscopic morphology and mirco-hardness were investigated. The microstructure evolution in laser transformation zone was also discussed. The results showed that when the laser power increased or the scanning speed decreased， the width and depth of the laser transformation zone increased. Laser transformation zone can be characterized into three smaller zones in general: micro-melting zone (MZ)， hardening zone (HZ) and transition zone (TZ). In this study， the microstructure in the MZ was ferrite， granular bainite and martensite， whereas the microstructure in the HZ was fully martensite， compared to the microstructure in the TZ which consisted of the relatively finer individual martensite and the structure mixed with ferrite and martensite. The average hardness of the HZ reached 320HV， which was 30% higher than that of the matrix. The wear resistance of the steel was significantly improved by 30% after the laser treatment.

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A Mathematical Model for Estimating the Lining Erosion of Blast Furnace Hearth Based on Profile Vectors and Genetic Algorithm

SHAO Lei， YU Shan， WANG Nan， ZOU Zong-shu

2016, 37 (6): 790-794. DOI: 10.12068/j.issn.1005-3026.2016.06.007

Abstract ( 746 )

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With respect to consecutive drainage， aggressive internal conditions and varying lining profile during production process in blast furnace hearth， a simple method is proposed for representing the lining profile by a set of lining profile vectors. It can convert the solving of a complicated inverse heat transfer problem with unknown geometries at a specified-temperature boundary into searching the optimal set of profile vectors in an optimization problem. Integrating numerical heat transfer theory and finite element method with genetic algorithm， an inverse problem oriented mathematical model has been developed， which can predict the lining profile of blast furnace hearth accurately. A testing example of elephant-foot erosion pattern on the basis of an intact ceramic cup synthetic hearth， is employed to examine the effectiveness， stability and accuracy of the model. The results indicate that the model would have a broad prospect of practical applications.

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Experimental Study of the Oxidation-Reduction Property of Cu-based Oxygen Carrier in the Fixed Bed

YU Qing-bo， WU Tian-wei， YAO Xin， WANG Kun

2016, 37 (6): 795-799. DOI: 10.12068/j.issn.1005-3026.2016.06.008

Abstract ( 561 )

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The Cu-based oxygen carriers were prepared by mechanical mixing method. The effects of reaction temperature， gas flow， the type and the fraction of inert carriers on the oxidation and reduction reactivity of Cu-based oxygen carriers were investigated in a fixed bed reactor. The results show that with the increasing of reaction temperature， the reduction reactivity decreases whereas the oxidation reactivity increases. However， when the gas flow increases， both oxidation and reduction reactivity increase. For the three kinds of oxygen carriers with different inert carriers， the oxidation reactivity is slight different， but the reduction reactivity has a striking contrast and the order of reduction reactivity is Cu/Mg>Cu/Zr>Cu/Si.Both oxidation and reduction reactivity increase with the increasing fraction of inert carriers.

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Numerical Simulation on the Charging Process of New DRI-Flap Distributor

LI Hai-feng， YOU Yang， ZOU Zong-shu， CAI Jiu-ju

2016, 37 (6): 800-805. DOI: 10.12068/j.issn.1005-3026.2016.06.009

Abstract ( 588 )

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The charging system of COREX melter gasifier consists of one coal-gimbal distributor and eight DRI-flap distributors. As the DRI-flag distributor is a new type of distributor， few research is found to help to understand the charging process of DRI-flap distributor in depth. In this study， a mathematical model of charging process of the DRI-flag distributor was developed based on discrete element method and was used to investigate the effect of operating parameters during charging process. The relationship between the flap angle and radial position was obtained when studying the effect of flap angle on the landing position. After examing the formation process and internal segregation of the stock pile， the size segregation in the radial direction was revealed. Meanwhile， the distribution of ore and coke in the radial direction was given during their mixture charging process. These modeling results can guide us to adjust charging mode in COREX production field.

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New Efficient Process Utilizing Ludwigite on Gas-based Shaft Furnace Direct Reduction and Electric Furnace Smelting Separation

CHU Man-sheng， ZHAO Jia-qi， FU Xiao-jiao， LIU Zheng-gen

2016, 37 (6): 805-809. DOI: 10.12068/j.issn.1005-3026.2016.06.010

Abstract ( 588 )

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In this work， oxide pellet was prepared from boron-bearing iron concentrate. A new process that the boron-bearing iron concentrate was directly reduced and separated by shaft furnace and electric furnace smelting， respectively. The corresponding reduction and separation theories were discussed. The results showed that boron-bearing iron concentrate pelletization can fully meet the requirements of the gas-based shaft furnace direct reduction process. After boasting at 1200℃ for 20minutes， the compressive strength of the finished pellet is higher than 2500N. When the H₂ to CO ratio is higher than 2/5 and the temperature is between 850℃ to 1000℃， the time for reducing 95% of the boron-bearing iron concentrate is between 10min to 60min and the expansion ratio is less than 15%. Boron and iron can be efficiently separated from DRI by electric furnace at 1500℃. The yields of both boron and iron can achieve up to 98%. The activity and the mass fraction of B₂O₃ in the slag can reach 89% and 21%， respectively， suggesting that this kind of slag can be used as high quality raw materials for the one-step boric acid production. The new process can efficiently separate and cleanly utilize boron-bearing iron concentrate.

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Effect of Process Parameters on the Compressive Strength of Iron Coke Hot Briquette

WANG Hong-tao， CHU Man-sheng， ZHAO Wei， LIU Zheng-gen

2016, 37 (6): 810-814. DOI: 10.12068/j.issn.1005-3026.2016.06.011

Abstract ( 672 )

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Iron coke hot briquette (ICHB) is a new type carbon iron composite， which is beneficial for blast furnace to decrease the temperature of thermal reserve zone and reduce CO₂ emission. In this paper， the effect of process parameters on the compressive strength of ICHB was investigated， associated with their functional mechanisms. The results showed that with the increase of iron ore addition ratio， the compressive strength of ICHB increased first and then decreased， which reached a higher value of 3490.89N with 15% iron ore addition. With increasing coal addition ratio， the compressive strength of ICHB increased， similar to the effect of hot briquetting temperature. When the hot briquetting temperature was 350℃， the compressive strength was up to 4305.50N. With the increase of carbonization temperature， the compressive strength of ICHB decreased first and then increased. However， the compressive strength increased first and then decreased with increasing carbonization time. Especially， when the carbonization time was 4h， the strength reached 3518.80N. Therefore， as the compressive strength is concerned， the reasonable preparation process parameters of ICHB are 10%~15% iron ore， 60%~70% bituminous coal， 300℃~350℃ hot briquetting temperature， 1000℃~1100℃ carbonization temperature and 2~4h carbonization time.

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Catalytic Property of Ni-Mo-Co Alloy Coating Prepared by Pulse Plating

KONG Ya-peng， CHEN Jian-she， LIU Kui-ren， HAN Qing

2016, 37 (6): 815-819. DOI: 10.12068/j.issn.1005-3026.2016.06.012

Abstract ( 704 )

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The Ni-Mo-Co alloy coating was prepared by pulse plating process. The effects of different electrodeposition conditions on the composition， apparent morphology and hydrogen evolution reaction (HER) activity of the Ni-Mo-Co coating were investigated. The results showed that with the increasing addition of cobalt salt， the cobalt content in the coating increased and the molybdenum content decreased. When the concentration of cobalt salt was up to 81 g/L， the content of elements became less changeable. Moreover， the Ni-Mo-Co coating appeared to be a uniform and dense layer and the corresponding HER overpotential decreased to the minimum value. With the Mo content of 40 wt%， the degree of amorphous structure and the catalytic activity (80℃，η₂₀₀=56mV) of the Ni-Mo-Co coating increased with increasing of the Co content. After galvanostatic electrolysis， the bubble phenomenon happened， which indicated a poor stability.

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Numerical Simulation of Electromagnetic Field in a Round Bloom Continuous Casting Mould with Eccentric Electromagnetic Stirring

REN Bing-zhi， CHEN Deng-fu， WANG Hong-dan ， QI Rui

2016, 37 (6): 820-824. DOI: 10.12068/j.issn.1005-3026.2016.06.013

Abstract ( 541 )

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A three-dimensional mathematical model was developed to study the electromagnetic field in a round bloom continuous casting mould with electromagnetic stirring (M-EMS). The simulation results of electromagnetic field were validated by the measured data from the experiments. The effects of stirring current intensity and frequency on magnetic flux density and electromagnetic force were investigated， and the electromagnetic field characteristics were also discussed after applying eccentric M-EMS. The results show that both magnetic flux density and electromagnetic force increase with increasing current intensity. When the stirring current frequency increases， the magnetic flux density decreases and the electromagnetic force increases first and then decreases with the maxima at 2.5Hz. Under the conditions of eccentric M-EMS， the electromagnetic force still appears to be circumferential distribution on the planes transverse to the strand. However， the magnitudes of both magnetic flux density and electromagnetic force show asymmetrical distribution， which are much larger at the side near the external arc of the continuous caster.

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Molecular Design and Explosive Properties of N₈ Isomers as Potential High Energy Density Materials

WANG Xiao-lin， GAO Yuan， JIANG Wei， ZHAO Xiao-lei

2016, 37 (6): 824-827. DOI: 10.12068/j.issn.1005-3026.2016.06.014

Abstract ( 735 )

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Twenty novel N₈ molecular structures with different shapes of ring， cage， ladder and etc are designed. Three high-precision quantum chemistry methods are used to optimize these structures and six thermodynamic stable molecular configurations have been screened out from them. Then the reliable theoretical predictions of their structural， electronic and explosive properties are performed to obtain the optimal structural parameters， energy， density， heat of formation and detonation velocity and pressure. The results show that a planar double five-membered cyclic structure has the most thermal stability among the six N₈ isomers because it has the lowest molecular tension， the minimum total energy and the maximum HOMO-LUMO energy gap. Moreover， the double five-membered cyclic and cubic structures possess the minimum and maximum heat of formation， respectively. It is also found that the theoretical values of detonation velocity and pressure of these six N₈ molecules are greater than those of the hexogen and octogen， which are well-known explosives. Therefore， the six N₈ molecules can be considered as potential excellent pollution-free candidates for high energetic materials.

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Analysis of Material Movement of Self-synchronization Vibration Conveyer for Dual-mass

HE Bin， ZHAO Chun-yu， HAN Yan-long， WEN Bang-chun

2016, 37 (6): 828-833. DOI: 10.12068/j.issn.1005-3026.2016.06.015

Abstract ( 668 )

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Through analyzing the material movement process of the self-synchronization vibration conveyer for dual-mass based on the material slippage theory， the movement of conveyer and material stationary response were obtained on the basis of subsection establishing and solving the dynamic differential equation. The influence of conveyer frequency， material mass， friction coefficient and vibrating direction angle on the speed and displacement of material movement were discussed by numeric analysis， then the results were verified by the numerical simulation. The result shows that there exists linear relation between slip acceleration of material and vibration conveyer in single horizontal direction. The material mass has no effect on material movement. The material transportation speed and displacement of reverse slide will increase with decreasing of the conveyer frequency. As the friction coefficient increases， the material transportation displacement， time of reverse slide and average speed will increase. The material transportation displacement， time of forward slide and average speed increase along with the vibrating direction angle increasing.

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Multi-field Coupling Dynamic Characteristics and Data Fitting Based on Kriging Model

YANG Wen-jun， YUAN Hui-qun， ZHAO Tian-yu

2016, 37 (6): 834-838. DOI: 10.12068/j.issn.1005-3026.2016.06.016

Abstract ( 587 )

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Aero-engine is increasingly to face the trend of higher load， efficiency and reliability， so that multi-field coupling problems are taken more and more attention. This research took the semal system of an aero-engine compressor as the research object， 3D flow field in the single sector and structural models were established by the method of cyclic symmetric. Considering the influence of former stator wakes， compressor flow field was simulated. Based on the Kriging model， load transfer of aerodynamic pressure and temperature achieved from flow field to blade structure. Then the coupling effects of aerodynamic pressure， temperature and centrifugal stress on compressor fatigue life were discussed. The results show that the load transfer with the Kriging model can meet the requirement of multi-field coupling dynamic calculation. In the low pressure compressor， centrifugal force plays a major role on deformation and stress of semal system， and bending stress induced by aerodynamic pressure and temperature can counteract part of bending stress induced by centrifugal force. However， temperature load makes the maximal deformation of blade-disc system increase.

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The Representation of Process Family Information Model Based on UML and XML

WANG Lin， ZHANG Yong-jian， ZHONG Shi-sheng

2016, 37 (6): 839-844. DOI: 10.12068/j.issn.1005-3026.2016.06.017

Abstract ( 554 )

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With the development and application of mass customization， the research focus about product family has been transferred from design to manufacturing， and the concepts of process platform and process family come with the transformation， in order to model the process family， the representation method of process family model based on UML and XML was proposed. In order to ensure the entity and the relationships between entities in process family， the process platform and process family were introduced first. And then based on the thinking of object oriented， UML static graph was adopted to describe the process family. For the purpose of engineering application of process family and information transmission and sharing among different systems， with the transformation rules from UML model to XML Schema， XML was adopted to represent the process family model. Finally， taken panel machining process of satellite plate for an example， the UML model of panel machining process family was constructed and the panel machining process family case was represented by XML.

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Parameterized Load Model Under Non-stationary Random Cyclic Conditions

JIANG Tao， FU Zhi-yi， WANG An-lin

2016, 37 (6): 845-850. DOI: 10.12068/j.issn.1005-3026.2016.06.018

Abstract ( 657 )

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Aiming at characterizing the load of earthmoving machinery under non-stationary random cyclic conditions for design and tests of its components， a parameterized model was proposed. In order to study the multi-way valve in the hydraulic excavator， the outlet pressure at valve port was decomposed into random term and trend term by wavelet transform. The stationary random term was described by “random term function” using the estimation of power spectral density， and the non-stationary trend term was expressed by “trend term function” using the function to fit with condition-variables. Then the two functions were combined to generate “cyclic condition load function”. Comparisons between simulated and test data prove that this function can accurately reconstruct random character in multi-way valve under non-stationary random cyclic conditions. The results also indicate that the modeling method will be an applicative reference for realizing the parametric expression of non-stationary random load with cyclic features in engineering application.

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Mechanism and Method of Pre-bending Design for the Wind Turbine Blades

GUO Xiao-feng， CHEN Jin， LI Song-lin

2016, 37 (6): 851-855. DOI: 10.12068/j.issn.1005-3026.2016.06.019

Abstract ( 888 )

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A new static aeroelastic analysis method for the HAWT was proposed based on the modified blade element momentum (BEM) theory. The deformation curves of the blade under different steady wind speeds were analyzed. The prebending design principles and a profile design method were developed. The static aeroelastic analyzing result of the prebending and unprebending blade shows that， the aerodynamic performance is influenced by the cross section shape change， blade axial and torsional deformation. The prebending blade’s actual power has certain decrease because of the blade torsional deformation. This study provides theoretical basis and design method for the blade.

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Characteristic Research on Steam Flowing Across Tubes Under the Interaction of Liquid Film and Liquid Droplet

LIU Hua， GONG Lu-yuan， SHEN Sheng-qiang， CHEN Xue

2016, 37 (6): 856-860. DOI: 10.12068/j.issn.1005-3026.2016.06.020

Abstract ( 612 )

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To investigate the two-phase flow characteristics under the interaction of liquid and gas over horizontal tubes， the rotated-square arranged tube bank was chosen and the VOF method was employed to propose an intertube droplet model. The thickness of liquid film and the droplet diameter was initialized according to the void fraction. The steam flowing process under the interaction of liquid film and droplet was simulated. The analyses of velocity field and pressure field were also illustrated. The results indicate that the calculated value of pressure drop coincides well with the experimental data at the small spray density. In the computational zone， the pressure in the bottom area is higher than that in upper area， and the minimum pressure distribution is in the lower right side near the droplet. The deformation of the liquid droplet in falling process is caused by the uneven distribution of pressure.

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Effects of Triton X-100 on Oxidative Activity of Acidithiobacillus ferrooxidans and on Chalcopyrite Bioleaching

ZHANG Rui-yang， WEI De-zhou， LIU Wen-gang， GAO Shu-ling

2016, 37 (6): 861-865. DOI: 10.12068/j.issn.1005-3026.2016.06.021

Abstract ( 674 )

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Triton X-100 was used to improve the bioleaching of chalcopyrite with Acidithiobacillus ferrooxidans， and its effects on ferrous and sulfur oxidative activities of At.ferrooxidans and bioleaching of chalcopyrite were investigated. Chalcopyrite after bioleaching was characterized by XRD. Results showed that the addition of Triton X-100 has little negative effect on ferrous-oxidizing activity of At.ferrooxidans， but it is favorable for that of sulfur. The copper extraction yield of chalcopyrite with 30mg·L^-1 Triton X-100 increases by 52.15 % compared with the bioleaching without Triton X-100. The elemental sulfur produced during bioleaching of chalcopyrite is efficiently bio-oxidized and dissolved by At.ferrooxidans in the presence of Triton X-100， consequently increasing concentrations of the bacteria and ferric ion in bioleaching system， thus enhancing the oxidation and dissolution of chalcopyrite.

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Effects of Particle Size Distribution on Hematite Flotation

LI Dong， YIN Wan-zhong， MA Ying-qiang， YAO Jin

2016, 37 (6): 865-868. DOI: 10.12068/j.issn.1005-3026.2016.06.022

Abstract ( 667 )

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Effects of the content of fine fractions (< 18μm) on hematite flotation were studied by using flotation tests， extended DLVO (EDLVO) theoretical calculations and kinetics of particle aggregation. The flotation results indicate that hematite recovery is related with the size of coarse particle (> 18μm) and particle size distribution. When the size of coarse particle is relatively large， the recovery of hematite is high. EDLVO theoretical calculations confirm that the fine particles could interface with the coarse particles and the attraction energy increases with the coarse particle size increasing. The flotation recovery increases with the particle size distribution becoming balance (the fine fractions equals the coarse fractions)， and the rate of particle coagulation is relatively high in this case which is analyzed by kinetics of particle aggregation. These conclusions could explain why the recovery of hematite is influenced by particle size distribution.

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Flow Characteristics of Discrete Ore Rock of Block Caving Based on Stochastic Medium Theory

ZHU Zhong-hua， WANG Li-guan， TU Xiao-teng， BI Lin

2016, 37 (6): 869-874. DOI: 10.12068/j.issn.1005-3026.2016.06.023

Abstract ( 638 )

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In order to accurately grasp the flow characteristics of ore and rock of block caving， a new method that combining attribute block model with stochastic medium theory was proposed. The procedure of simulation flow is as follows: attribute block model was established to fit and discretize target region. Block attributes were obtained by attribute interpolation technique. A proper flow model for programming was established. The concept of draw-out index and block index was put forward to analyze the flow characteristics of the rock under different oredraw conditions. Flow simulation was realized based on the proposed method in 3D visualization platform with C++ language. The results show that with the draw height increasing， the length of the long axis of the draw out body increases linearly， and the length of the short axis and the eccentricity increase gradually， showing a power exponential relationship. Under constant block index， with the increase of draw-out index， the ellipsoid of the ore body is gradually developed， the eccentricity ratio is increased， and the average depth of the depression increases. Under constant draw-out index， with the increase of block index， the eccentricity of the ellipsoid is decreased.

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Study on the Parameters Prediction Model of Flocculating Sedimentation of Crude Tailings

ZHANG Qin-li， LIU Qi， ZHAO Jian-wen

2016, 37 (6): 875-879. DOI: 10.12068/j.issn.1005-3026.2016.06.024

Abstract ( 572 )

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In order to get the optimum parameters of flocculating sedimentation， back propagation neural network and genetic algorithm were applied to establish the flocculation sedimentation parameters prediction model of the crude tailings. The flocculating agent and tailings concentration consumption were used as the input data and the sedimentation speed was confirmed to be the output data. The learning and training samples were received by the orthogonal experiments to build neural network prediction model. Then， the optimum parameters of flocculating sedimentation were received after using genetic algorithm finding optimal in parameters prediction model of the crude tailings. The selected parameters prediction model was used in Hemushan iron mine. The results showed that the flocculating agent consumption is 12g/t and tailings concentration is 17%， the sedimentation speed is 1.31m/h， these parameters meet the production requirements. The flocculating agent consumption required is 20% less than the original production when using these flocculating sedimentation parameters. The application of the model indicates that it provides a new method to optimize the flocculating sedimentation parameters with a good effect.

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Analysis on the Degradation of Environmental Estrogen 17β-estradiol by Ultraviolet(UV) Light-activated Sodium Persulfate

GUO Hong-guang， LIU Yang， ZHANG Yong-li

2016, 37 (6): 880-885. DOI: 10.12068/j.issn.1005-3026.2016.06.025

Abstract ( 680 )

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The problem of environmental estrogens caused wide spread concern in natural water， using low pressure mercury lamps activated sodium persulfate (PS) composite system to degrade 17β-estradiol (E2)of residual in the water which is a typical environmental estrogens. The effect of different initial pH， sodium persulfate concentration， common anions(Cl^-，HCO^-₃，NO^-₃) on degradation of E2 and the mechanism of reaction kinetics were investigated. The results showed that the degradation of E2 by UV/PS system follows pseudo-first-order kinetic model and the optimum pH is 7.0， the removal of E2 increases with adding the sodium persulfate concentration， the environmental anion may promote the degradation of E2. It is demonstrated that the principal free radical is·SO^-₄ in the system. This study provides a strong theoretical basis for UV/PS advanced oxidation degradation of environmental estrogen.

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Numerical Simulation of Thermal Environment for Double-tube Heating of Biomass Gasification

YAN Fang， XU Kai-li， YAO Xi-wen， ZHANG Xiu-min

2016, 37 (6): 886-890. DOI: 10.12068/j.issn.1005-3026.2016.06.026

Abstract ( 557 )

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In order to guarantee safety operation of the biomass gasification station in the north of China in winter， a method which makes the waste heat of biomass gasification reaction go into purification room by using axial flow fan and double-tube is proposed. Simulation is performed for heat environment of the heated purification room of the biomass gasification station by computational fluid dynamics (CFD) approach using Fluent. The temperature of purification room can reach to 254K when the situation temperature in Shenyang is 243.15K. The temperature of purification room will continue to enhance to 278K when the heat measures are taken to envelope. And the requirement of freeze prevention is met and the feasibility of double-tube heating is proved. It provides some references for the transformation of freeze prevention of biomass gasification station in northern China.

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Application of Simplex Particle Swarm Optimization Algorithm in Determining the Minimum Factor of Safety of Embankment

SHA Cheng-man， BIAN Dan， YANG Dong-mei

2016, 37 (6): 890-894. DOI: 10.12068/j.issn.1005-3026.2016.06.027

Abstract ( 481 )

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In the design of highway， the simplified bishop algorithm is used to analyze the body stability of the embankment itself and the overall stability both embankment and foundation according to the requirements of specification generally. It is used to determine the most dangerous slope sliding surface and the corresponding minimum factor of safety. The enumeration algorithm frequently adopted in engineering practice requires a given hunting zone and its computation speed is slow. Traditional optimization algorithm such as step-acceleration method results in local extremum and other shortcoming easily. Based on particle swarm optimization (PSO)， a method combining simplex method and particle swarm optimization (SM-PSO) is put forward. And it is proved that it has obvious improvement in convergence speed and adaptability when comparing with PSO algorithm in optimization efficiency and optimization performance.

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Resistance to Sulfate Attack of Hybrid Fiber Concrete Under Dry-Wet Cycles

LI Yi， ZHANG Shuang

2016, 37 (6): 895-899. DOI: 10.12068/j.issn.1005-3026.2016.06.028

Abstract ( 679 )

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The dry-wet cycle method is adopted to study sulfate resistance of standard cubic plain concrete and hybrid fiber concrete specimens (150mm×150mm×150mm). The anti-sulfate corrosion performance is tested at the erosion age of 0， 30， 60， 90， 180， 210 days with sodium sulfate erosion solution concentrations of 800 and 6000mg/L. The results show that when the erosion age is 210 days， corresponding to concentrations of 800 and 6000mg/L， compressive strength of plain concrete decreases by 5.6% and 10.0% and splitting tensile strength decreases by 3.0% and 5.1% respectively. Compressive strength of hybrid fiber concrete decreases by 4.0% and 6.3% and splitting tensile strength decreases by 0.51% and 3.8% respectively. When erosion depth comes to 1.5mm， SO^2-₄ concentrations of plain concrete are 0.83% and 1.03%， while hybrid fiber concrete are 0.79% and 1.0% respectively.

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Mechanical Property and Constitutive Relation of Foamed Particles Concrete

XU Shuang， ZHU Fu-sheng， ZHANG Jun， CHU Xiao-xi

2016, 37 (6): 899-903. DOI: 10.12068/j.issn.1005-3026.2016.06.029

Abstract ( 902 )

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Considering two factors of the polystyrene particle content and wet density， 25 groups of foamed particles concrete with different proportions were prepared. The strain rate effect is not obvious by studying the loading speed on stress-strain curve of foamed particles concrete. The effect of different polystyrene particles content and different wet density on stress-strain curve of foamed particles concrete was also studied. The results show that the influence of polystyrene particles content and wet density on mechanical properties was obvious. Through the analysis of modulus of elasticity， crushing stress， crushing strain and other parameters， combining with test results， a phenomenological uniaxial compressive constitutive model of foamed particles concrete is established. Comparing test results with modeling predictions， good agreements are obtained between the phenomenological constitutive model and test results.

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Optimization Configuration Method for Service Elements Considering Customer Choice Behavior

YU Chao， FAN Zhi-ping

2016, 37 (6): 904-908. DOI: 10.12068/j.issn.1005-3026.2016.06.030

Abstract ( 568 )

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Service elements configuration is an important link of service design. How to consider customer choice behavior so as to optimize the service elements configuration is an important issue which needs to be concerned. An optimization configuration method for service elements considering customer choice behavior was proposed in order to solve the service elements optimization configuration problem. Firstly， the aspiration level for each service item and the demand satisfaction degree for each service element were obtained by questionnaire survey among target customers. Then， target customers’ psychological perception of elation and disappointment was described by constructing the utility function. Furthermore， the customer choice behavior model for service product was established to calculate the probability of target customer group choosing the service product. Moreover， the optimal service elements configuration alternative was determined by establishing and solving the optimization model. Finally， the feasibility and validity of proposed method are illustrated by an example.

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Study on Non-insulated Superconducting Magnet Coils and Performance Testing

BAI Zhi-ming， CHEN Chuan， ZU Wei-zhen， ZHANG Hua-rong

2016, 37 (6): 908-912. DOI: 10.12068/j.issn.1005-3026.2016.06.031

Abstract ( 803 )

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The structure of superconducting magnet coils without turn-to-turn insulation was analyzed， and the effects of total number of layers and the turns for each layer on the equivalent total resistance and charge-discharge process of the coils were tested. The experimental results show that the variation trend of the equivalent total resistance is completely different when the total layer number is odd or even， but the order of magnitude is several multiples of the contact resistance between adjacent turns. The charge-discharge process of coils is directly affected by the equivalent total resistance. If the total resistance is greater， the excitation time will be shorter， but the induced voltage will be also larger， and the Joule heat will be increased. Therefore， the appropriate choice of equivalent total resistance and no insulation filling material are particularly important for the design of non-insulated superconducting magnet coils.

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