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    Information & Control
    Virtual Machine Placement Strategy Based on Multi-objective Optimization
    LIU Jun, DAI Fu-cheng, XIN Ning
    2022, 43 (5):  609-617.  DOI: 10.12068/j.issn.1005-3026.2022.05.001
    Abstract ( 436 )   HTML ( 31)   PDF (1053KB) ( 443 )  
    To optimize the performance, utilization and balance of physical servers in the process of virtual machine placement, an improved placement algorithm based on reinforcement learning is proposed. Firstly, the single reward in reinforcement learning algorithm is replaced by multi-dimensional rewards composed of dynamic objectives, and then the multi-dimensional reward values corresponding to each placement scheme are output by the predictor. The input of the predictor is the resource pool status, optimization target, and target proportion. Finally, the proportions of different optimization objectives are adjusted according to the resource pool status to optimize the targets. The results of CloudsimPy show that the improved algorithm can deploy more virtual machine requests with the higher placement success rate and lower delay consumption under the same resource.
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    Easily to Expand and Efficient Decentralized Cross Chain Exchange Protocol Based on Smart Contract
    JIAO Zi, ZHOU Fu-cai, WANG Qiang
    2022, 43 (5):  618-624.  DOI: 10.12068/j.issn.1005-3026.2022.05.002
    Abstract ( 375 )   HTML ( 17)   PDF (738KB) ( 230 )  
    Aiming at the problems of low transaction efficiency, high handling fee, and difficulty in the expansion of existing decentralized cross chain exchange schemes, a cross chain exchange based on smart contract(CCE-SC)is proposed. The protocol uses smart contracts to ensure the decentralization and security of cross chain exchange. It implements low-cost and efficient cross-chain transactions through three algorithms, i.e., strategy formulation, strategy synchronization, and blockchain consensus verification. Each chain in the protocol only needs to deploy a smart contract that includes pool module, record management module, chain relay module and oracle module to realize cross chain exchange across multiple chains. The performance of the protocol is analyzed through experimental tests. The experimental results show that the protocol greatly improves the efficiency of cross chain exchange and reduces the handling fee overhead.
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    Research on the Importance of Network Nodes Based on Attribute Information and Structural Characteristics
    KONG Zhi, SUN Qi, KOU Xiao-yu, WANG Li-fu
    2022, 43 (5):  625-631.  DOI: 10.12068/j.issn.1005-3026.2022.05.003
    Abstract ( 465 )   HTML ( 15)   PDF (667KB) ( 334 )  
    Most of the existing node importance ranking methods only study the topology of the network, ignoring the attribute information contained in the network nodes themselves. Attribute information is very important, but there is widespread incompleteness. Incomplete attribute information is closely related to the importance of nodes. Aiming at these problems, a network node importance analysis method based on superior rough set theory and TOPSIS method is proposed, which combines network structure characteristics and node attribute information and overcomes the limitations of single topological structure analysis. Finally, the proposed method is applied to the user importance evaluation in Weibo social network and compared with other methods. The results show that the ranking results of this method can well synthesize the importance of each node in attribute information and structural characteristics and can fully reflect the importance of each node.
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    Research on the Mapping Between Crime and Network Behavior Characteristics
    LU Yu-hui, ZHAO Hai, LIU Xiao, SHI Han
    2022, 43 (5):  632-638.  DOI: 10.12068/j.issn.1005-3026.2022.05.004
    Abstract ( 415 )   HTML ( 9)   PDF (1688KB) ( 171 )  
    Thefts, robberies and drug cases from 2012 to 2017 in Chicago,United States are selected to study. A method of constructing criminal network based on spatio-temporal influence domain is proposed, and the mapping analysis is carried out according to the behavior characteristics of criminal manifestation and network behavior characteristics. The experimental results show that the criminal networks constructed by the proposed method exhibit scale-free and small-world characteristics under different crime types and different network scales. The local area showed high aggregation and different aggregation characteristics. The degree of corporatization of criminal networks is obvious. It can be seen that complex network means can be used to conduct further in-depth discussion on criminal network modeling and topological characteristics analysis, so as to provide new ideas for the dynamics study of different criminal patterns, prevention and resource allocation.
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    Interpolation of Missing Physiological Data of ICU Patients Based on Deep Embedded Clustering
    LI Jian-hua, ZHU Ze-yang, XU Li-sheng, SUN Guo-zhe
    2022, 43 (5):  639-645.  DOI: 10.12068/j.issn.1005-3026.2022.05.005
    Abstract ( 491 )   HTML ( 7)   PDF (1435KB) ( 171 )  
    The data in electronic medical records are often missing, significantly affecting the analysis results. The ICU(intensive care unit)patients’ data in MIMIC database were analyzed for missing value interpolation, and the dataset consists of 23 groups of commonly used clinical physiological variables and 5260 samples without missing values. A K-nearest neighbor interpolation method was proposed based on deep embedded clustering. This method takes deep embedded clustering as the core, constructs the sample proximity matrix through multiple clustering, and then regards the average value of K-nearest neighbor of missing samples as the missing values. Compared with mean interpolation, median interpolation, a posteriori distribution estimation interpolation and conditional mean interpolation, the proposed method obtains higher similarity between the interpolated results and the original data, and better retains the differences between various samples.
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    Materials & Metallurgy
    Effect of Aging Treatment on Microstructure and Mechanical Properties of 10Ni10Mn2CuAl Steel
    DONG Yan-wu, PENG Fei, TIAN Jia-long, JIANG Zhou-hua
    2022, 43 (5):  646-651.  DOI: 10.12068/j.issn.1005-3026.2022.05.006
    Abstract ( 484 )   HTML ( 8)   PDF (1991KB) ( 150 )  
    A new type of high-strength marine steel with the composition of 10Ni10Mn2CuAl was designed by means of precipitation strengthening from hybrid Cu-rich and NiAl (Mn) phases, and the effect of aging treatment on microstructure and mechanical properties of the 10Ni10Mn2CuAl steel was studied. The precipitating temperature and the phase content of the precipitations were calculated by Thermo-Calc software. The typical inclusions in the matrix and microstructure after aging treatment were analyzed by optical,scanning electron microscopes,the hardness and room-temperature tensile tests were carried out. The results show that the precipitating temperature of Cu-rich phase is in the range of 300~606℃ and the maximum content of the precipitation is 1.41%. With the aging time increasing, the martensitic lath changes from the coarse grain to the refined one, corresponding to the hardness reaching the maximum and then becoming stable. Meanwhile, as the aging temperature increases, the time to reach the maximum hardness is shortened owing to the precipitation process accelerated by higher temperature. Under the heat treatment of the aging at 500℃ for 24 h, the best performance of the experimental steel is achieved with yield strength of 1435.51MPa, tensile strength of 1555.42MPa and elongation of 8%.
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    Thermodynamic Analysis of Aluminum and Titanium Oxidation During Electroslag Remelting Process of Inconel 625 Alloy
    LIU Fu-bin, ZHANG Hai-bao, GAO Jun-zhe, GENG Xin
    2022, 43 (5):  652-659.  DOI: 10.12068/j.issn.1005-3026.2022.05.007
    Abstract ( 455 )   HTML ( 13)   PDF (932KB) ( 124 )  
    Slag-metal equilibrium experiments and a thermodynamic model of the action concentration based on the ion and molecule coexistence theory (IMCT) were used to study in controlling Al and Ti elements during the electroslag remelting (ESR) process of Inconel 625 alloy. The influencing mechanisms of slag components on burning loss of Al and Ti were investigated and the relationship of the activity and its ratio for each slag component with chemical composition in the system was provided, respectively. The results indicate that the slag system with the TiO2 of 3% has a good effect on the Al and Ti preservation. The CaO in the slag will cause different degrees of burning loss of Al and Ti, in which the excess CaO can lead to the phenomenon of burning the Ti and increasing the Al content. The Al oxidation is restrained with the temperature, in contrast to the Ti oxidation. Eventually, at the 1823K, the composition of the slag system is selected as w(CaF2)=50%~60%, w(Al2O3)=15%~20%, w(CaO)=14%~20%, w(MgO)=3% and w(TiO2)=2.5%~3.5%, respectively, so as to reduce the Al and Ti burnout effectively during the ESR process of Inconel 625.
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    Mechanical Engineering
    Dynamic Performance Analysis of Line Inspecting Robots Considering Time-Varying Loads
    LI Xiao-peng, FAN Xing, LI Kai, ZHANG Ling-yue
    2022, 43 (5):  660-667.  DOI: 10.12068/j.issn.1005-3026.2022.05.008
    Abstract ( 403 )   HTML ( 3)   PDF (1722KB) ( 111 )  
    When the power transmission line inspection robots(PTLIRs)cross obstacles, the phenomenon of control overshoot and vibration will appear due to the influence of time-varying loads. A method for analyzing the dynamic performance of PTLIRs in obstacle crossing state is studied considering the time-varying characteristics of load inertia. The dynamics equations of the slewing mechanism of the dual-arm PTLIR are established with the two-inertia-system, and further the kinematics and dynamics modeling are carried out based on the modified D-H method and Lagrangian mechanics, including assigning coordinate system, solving Lagrange’s equation, using inertia matrix to calculate the load moment of inertia, etc. The controller parameters are designed by selecting appropriate damping coefficient, and the changes of the damping coefficient and the natural angular frequency are used to analyze the dynamic performance of the PTLIR. The research results are helpful to analyze the dynamic performance of the dual-arm PTLIR affected by the time-varying load inertia when crossing obstacles, and can be used to debug the servo parameters of the robot.
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    Analysis of Dynamic Stiffness of the Elastic Ring Support Structure and Its Influence on the Rotor System
    LUO Zhong , LIU Jia-xi , LIU Kai-ning , SUN Kai
    2022, 43 (5):  667-673.  DOI: 10.12068/j.issn.1005-3026.2022.05.009
    Abstract ( 536 )   HTML ( 3)   PDF (1462KB) ( 367 )  
    Aiming at the stiffness characteristics of the elastic ring support structure used in the aero-engine rotor system, the dynamic stiffness analysis and experimental tests as well as the analysis of its influence on the natural characteristics of the rotor system are carried out. First, a finite element model of the elastic ring support structure is established to calculate its dynamic stiffness, then the dynamic stiffness testing and verification is conducted. The experimental test results are basically consistent with the simulation results, which verify the correctness of the finite element analysis method of the elastic ring structure. Then, a finite element model is built which includes the rotor system and the elastic ring structure. Besides, the influence of the rotor system on the critical speed under the conditions of static and dynamic stiffness is studied. The results show that the dynamic stiffness of the elastic ring support structure has a significant impact on the critical speed. The first-order critical speed is reduced by 26%, and a new resonance frequency is generated. Therefore, the dynamic stiffness of the support structure should be fully considered when analyzing the natural characteristics of the rotor system.
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    Research on Static and Dynamic Characteristics of the Optical Free-Form Milling Machine
    LI Qi, YU Tian-biao, WANG Wan-shan
    2022, 43 (5):  674-680.  DOI: 10.12068/j.issn.1005-3026.2022.05.010
    Abstract ( 412 )   HTML ( 12)   PDF (3845KB) ( 158 )  
    An optical free-form milling machine is designed according to the technological characteristics of optical component manufacturing and the finite element(FE)modeling and static and dynamic characteristics analysis of the optical free-form surface milling machine are carried out. The results show that, at the original position under gravity load, when the gravity balance device is not working, the straightness of guide rail is 0.7μm, and when the gravity balance device is working, the straightness of guide rail is 0.035μm, when the gravity balance device is not working, the straightness of lead screw is 2.3μm, and when the gravity balance device is working, the straightness of lead screw is 0.2μm. The natural frequencies of the optical free-form surface milling machine with different structural schemes and material schemes are extracted, and the vibration mode shows that the first vibration mode of the milling machine that affects the machining precision is the third order, the optimal design scheme of dynamic characteristics is that the Z-axis motor of the milling machine is installed on the roof and the milling machine structure material uses natural granite, and the milling machine structure material using natural granite compared with cast iron can significantly improve the dynamic characteristics of the milling machine.
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    Preparation of Coated Micro-grinding Tools and Experimental Research on Grinding Surface Quality
    WEN Xue-long, WANG Cheng-bao, GONG Ya-dong, SUN Fu-qiang
    2022, 43 (5):  681-688.  DOI: 10.12068/j.issn.1005-3026.2022.05.011
    Abstract ( 421 )   HTML ( 2)   PDF (2576KB) ( 100 )  
    Coated micro-grinding tools were prepared by vacuum radiofrequency(RF) sputtering. The preparation mechanism of surface coating of micro-grinding tools was discussed. The grinding surface quality of coated micro-grinding tools was experimentally studied for brass materials, and the effects of different processing parameters and factors on the grinding surface properties of coated micro-grinding tools were analyzed. The experimental results showed that with the increase of grinding speed and the decrease of grinding depth and feed speed, the surface roughness of brass shows a decreasing trend, the surface morphology is smoother and the surface quality is better. Under the same grinding process parameters, the grinding force of coated micro-grinding tools is lower than that of uncoated micro-grinding tools. Compared with uncoated micro-grinding tools, coated micro-grinding tools with the same particle size can improve the surface adhesion of wear debris, and increase the service life of coated micro-grinding tools to a certain extent.
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    Theoretical Calculation Method of Reliability for Multi-state Phased-Mission Systems
    SUN Yao, SUN Zhi-li, ZHOU Jie, WANG Jian
    2022, 43 (5):  689-695.  DOI: 10.12068/j.issn.1005-3026.2022.05.012
    Abstract ( 732 )   HTML ( 10)   PDF (1585KB) ( 247 )  
    Multi-state phased-mission systems(MS-PMSs)are often used in critical systems and require high reliability. However, their reliability calculation is relatively difficult. In order to make an accurate prediction of reliability for such systems, the theoretical calculation method of reliability for MS-PMSs with component degradation conforming to Markov process is studied. First, the reliability for such systems is defined based on the relationship between working efficiency and demand. Then, according to the conditional probabilistic theory, the probability of mission success is formulated. On the basis, according to the Markov property of component degradation and the dependence on component states among phases, the theoretical calculation method of reliability for MS-PMSs is derived, and a fast exhaustion method of component state combination is proposed to improve the computational efficiency of the calculation method. Finally, by comparing with the Monte-Carlo simulation method, the accuracy and computational effectiveness of the derived theoretical calculation method are verified.
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    Optimization of Turning Parameters of GH4169 Based on Reliability
    HUANG Xian-zhen, SUN Liang-shi, DING Peng-fei, ZHU Hui-bin
    2022, 43 (5):  696-702.  DOI: 10.12068/j.issn.1005-3026.2022.05.013
    Abstract ( 443 )   HTML ( 4)   PDF (565KB) ( 172 )  
    It is critical to optimize the cutting parameters in order to increase the machining efficiency as much as possible while ensuring tool life. Therefore, a model of tool wear in the turning process is established to predict tool wear at any time under various cutting conditions. Thereby, a model of tool life is derived. Considering the influence of uncertain parameters on turning processing, a reliability-based optimization model of turning is established, and the optimization model is solved by the sequential optimization and reliability assessment(SORA)method to obtain the optimal cutting parameters. Finally, an example verifies the advantage and feasibility of this method in the parameter optimization of turning nickel-based superalloy GH4169.
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    Resources & Civil Engineering
    Experimental Study on Pre-concentration and Suspension Magnetization Roasting of Donganshan Iron Ore Flotation Tailing
    SHAO An-lin , SU Xing-guo, HAN Yue-xin, LI Yan-jun
    2022, 43 (5):  703-708.  DOI: 10.12068/j.issn.1005-3026.2022.05.014
    Abstract ( 509 )   HTML ( 3)   PDF (824KB) ( 182 )  
    To achieve the utilization of the flotation tailing of Donganshan iron ore, pre-concentration and suspension magnetization roasting tests were carried out. The results indicate that pre-concentration of the flotation tailing mainly consists of hematite, limonite, siderite and quartz, and iron grade is 31.13%. The appropriate suspension magnetization roasting conditions were determined as roasting temperature of 520℃, roasting time of 20min, H2 concentration of 20%, and gas flow rate of 600mL/min. The roasted product was benefited by low-intensity magnetic separation, and the concentration with iron grade of 64.23% and recovery of 79.53% was obtained. The analysis on roasted product by physical iron phase, XRD, and VSM indicates that the hematite, limonite, and siderite are reduced to magnetite during the suspension magnetization roasting process, and the saturation magnetization and magnetic susceptibility obviously increase.
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    Effect of Fine Talc on Sulfurized Flotation of Malachite
    LIU Yu-tong, YIN Wan-zhong, SHENG Qiu-yue, YAO Jin
    2022, 43 (5):  709-717.  DOI: 10.12068/j.issn.1005-3026.2022.05.015
    Abstract ( 424 )   HTML ( 5)   PDF (1218KB) ( 117 )  
    It is found that the addition of fine-grained talc reduces the floatability of malachite on sulfurized flotation by flotation test, and the higher the content of fine-grained talc, the greater the influence on the floatability of malachite.Zeta potential measurements, adsorption tests, SEM-EDS test and EDLVO theory calculation illustrated the reason for the influence of fine-grained talc on sulfurized flotation of malachite. The results show that the adsorption of appropriate amount of Na2S on the surface of malachite is the key to the success of sulfidization-xanthate flotation. The fine-grained talc adsorbs on the surface of malachite, and the adsorption of Na2S doesn’t occur on the surface of talc. Therefore, the fine-grained talc weakens the effect of sulfidization on the surface of malachite and reduces the floatability of malachite.
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    Effect of Feed Concentration on Separation Performance of Cyclone Separation Column
    HOU Duan-xu, WEI De-zhou, CUI Bao-yu, ZHAO Qiang
    2022, 43 (5):  718-723.  DOI: 10.12068/j.issn.1005-3026.2022.05.016
    Abstract ( 408 )   HTML ( 5)   PDF (2126KB) ( 135 )  
    The effects of feed concentration on the separation performance and particle movement behavior of the cyclone separation column were investigated based on numerical experiments. The results show that the increase of feed concentration reduces the recovery of particles in the underflow, increases the cut size, and decreases the misplacement of fine particle in the underflow. However, an excessively high feed concentration results in coarse particles misplaced in overflow. A high feed concentration means that the particle aggregation degree in the cyclone separation column, and the amounts of particles moving with the internal swirling flow increase. The axial velocity of particles increases with the increase of feed concentration on the Z=-400mm plane. The internal swirling flow region that the particles moving towards the spigot need to pass through increases, causing the increase of the possibility of the coarse particles being trapped by the inner swirling flow. The increase of the feed concentration reduces tangential velocity of particles on the Z=-400mm plane, leading to the decrease of centrifugal force on particles and the increase of the possibility of particles migrating inward, further increasing the aggregation of particles in the internal swirling flow region.
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    Uniform Flow and Stress Evolution Laws of Caved Ore and Rock Partides Between Multiple Drawpoints
    SUN Hao , SU Nan , JIN Ai-bing , CHEN Shuai-jun
    2022, 43 (5):  724-732.  DOI: 10.12068/j.issn.1005-3026.2022.05.017
    Abstract ( 430 )   HTML ( 2)   PDF (3697KB) ( 89 )  
    Aiming at the problems such as the threshold of drawpoint spacing and stress distribution in the research of multiple draw interaction, numerical tests based on the rigid block model were carried out under the conditions of different drawpoint spacings and draw modes, and uniform flow and stress evolution laws of caved ore and rock between multiple drawpoints were quantitatively studied. The results showed that the threshold of drawpoint spacing that produces uniform flow of caved ore and rock lies between 1.0 and 1.25 times of the maximum width of the isolated movement zone under the condition of multiple drawpoints. There is an obvious stress arching effect in the particle flow system, and the vertical stress above movement zones gradually transfers to the immobile zones on both sides during the draw process. The maximum vertical stress at the bottom of stope is nearly 1.8 times of the initial vertical stress within the range of values studied. The coordination number within the immobile zones is about 8~9 during the draw process, and the lower the space height, the larger the coordination number is. Within the movement zones, the closer to the drawpoints, the looser the caved ore and rock are, and the more disordered the migration and contact variations among particles are.
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    Quantitative Risk Assessment for Deep Tunnel Failure Based on Fuzzy Comprehensive Evaluation
    LIU Jian-po, WU Feng, WANG Ren, ZHANG Jun-jie
    2022, 43 (5):  733-739.  DOI: 10.12068/j.issn.1005-3026.2022.05.018
    Abstract ( 375 )   HTML ( 7)   PDF (1108KB) ( 161 )  
    The spatial and temporal distribution of tunnel failure is very complex due to geologic heterogeneity and mining processes variability in deep metal mines. The quantitative risk assessment for deep tunnel failure was performed at the Ashele copper mine, and the risk assessment was completed by comprehensively considering the evaluation indexes of geological conditions, mining process, and microseismic data. A weighted distribution of evaluation indexes was determined by implementation of an entropy weight method. The results showed that the five largest weights of the model are attributed to microseismic(MS)indexes, accounting for more than 80% of the total weight, which indicates that the MS indexes play a dominant role in the risk assessment of tunnel failure. The evaluation accuracy rate of tunnel failure sample data based on the fuzzy comprehensive evaluation method is close to 90%. Which can realize the quantitative risk assessment for regional deep tunnel failure, and meet the needs of the prevention and control of regional ground pressure hazards as well as the systematic optimization of mining process in deep metal mines.
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    Petrogenesis for Late Neoarchean Era High Magnesian Andesites in the Anshan-Benxi Area
    GUO Rong-rong, LI Zong-hui, HUANG Xiao
    2022, 43 (5):  740-747.  DOI: 10.12068/j.issn.1005-3026.2022.05.019
    Abstract ( 511 )   HTML ( 6)   PDF (1781KB) ( 129 )  
    The high magnesian andesites(HMAs)are first recognized from the Anshan-Benxi area, which comprise mineral assemblages of amphibole+plagioclase+mica+quartz+minor pyroxene. The Anshan-Benxi HMAs are interlayered with ~2.55~2.52Ga BIF and supracrustal rocks, therefore indicating that they are late Neoarchean products. Whole-rock major and trace geochemical results reveal that the Anshan-Benxi HMAs represent primary magmas with high MgO, Cr and Ni contents, low FeOT/MgO ratios and calc-alkaline features, and are characterized by typical island arc compositions with strongly fractionated REE patterns and negative Nb-Ta-Ti anomalies. Besides, the Anshan-Benxi HMAs are geochemically analogous to ~2.7Ga HMA in the Wawa greenstone belt and Phanerozoic sanukoid HMA in the Setouchi. Taken together, the Anshan-Benxi HMAs are interpreted products of partial melting of mantle peridotites which are previously metasomatized by subducting slab released melts, consisting with a late Neoarchean subduction geodynamic setting in the Anshan-Benxi area.
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    Mechanism of Combustible Gas Production in Aluminum Alloy Sludge
    LI Yu-xin, XU Kai-li, WANG Ben, GENG Li-yan
    2022, 43 (5):  748-754.  DOI: 10.12068/j.issn.1005-3026.2022.05.020
    Abstract ( 494 )   HTML ( 4)   PDF (1138KB) ( 105 )  
    Based on the gas production experiment of sludge quantity, standing time and before and after impurity removal, combined with SEM, particle size analysis, element analysis and microbial community analysis, the composition and law of gas production were analyzed to study gas production mechanism. The experimental results show that the gas produced by the sludge is composed of H2, CO2 and a small amount of CH4. The gas production is proportional to the amount of sludge and the standing time. The mechanism of gas production is that fermentation and hydrolysis bacteria produce H2 and CO2 in the metabolic process, and produce acidic substances which can corrode the protective film on the surface of aluminum alloy and form holes. Moisture enters the interior of particles along the holes and reacts with the alloy to produce hydrogen. H2 and CO2 provide metabolic materials for Methane archaea in sludge to produce CH4.
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    Simulation Study on Flow Characteristics of Hot Blast in Bustle Pipe of Blast Furnace
    SHI Ben-hui, LIU Bing-nan, LUO Zhi-guo, ZOU Zong-shu
    2022, 43 (5):  755-760.  DOI: 10.12068/j.issn.1005-3026.2022.05.021
    Abstract ( 457 )   HTML ( 6)   PDF (2702KB) ( 240 )  
    Numerical simulation of hot blast flow in the bustle of a 2580m3 blast furnace in ANSTEEL was carried out to explore the internal mechanism of non-uniform blast distribution by tuyeres. The results show that, under the condition of uniform tuyere size, the main stream in the bustle is not unidirectional, but with back flow. The hot blast enters the bustle pipe and directly impact the branch pipes beside the 0° position, resulting in large blast volume in the neighbor tuyeres. After entering the bustle pipe, two streams of blast will collide finally at the opposite of the inlet of the bustle pipe(i.e. at the 180° position), resulting in large blast volumes in the corresponding tuyeres. After the collision, part of the blast flow moves backward along the lower part and the inner side of the bustle pipe. At the 90° and 270° positions of the bustle pipe, the backward flows collide again with forward flow, resulting in large blast volumes in the corresponding tuyeres. By comparing and analyzing the practical tuyere-size adjustment measures of the blast furnace in ANSTEEL, it is found that the adjustment measures were basically consistent with the results of the present study.
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