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15 April 2019, Volume 40 Issue 4 Previous Issue    Next Issue
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Information & Control
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Information & Control

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Information Entropy-Based Supply Chain Uncertainty Under Push/Pull Strategies ZHAO Wen-dan， WANG Ding-wei 2019, 40 (4):  457-461.  DOI: 10.12068/j.issn.1005-3026.2019.04.001 Abstract ( 695 )   HTML   PDF (402KB) ( 668 )   Taking the 3-level multi-product supply chain as an example，the supply chain was ran by using four strategies， i.e.， Push， Pull， hybrid Push & Pull and improved Push. The global uncertainty of supply chain was quantified by total entropy ratio. Genetic algorithm(GA) was combined with simulation-based optimization(SBO) method to deal with the difficulty of large amounts of computation and uncertainty. The gain in the control law being as the decision variable， the uncertainty was optimized， and other common performance indicators such as customer satisfaction， excess inventory， delayed delivery and total cost were calculated under the optimal decision variables. The simulation results showed that when the demand exceeds supply， the hybrid Push & Pull strategy can reduce the total cost. When the supply exceeds demand， the improved Push strategy can minimize the uncertainty of the supply chain. References | Related Articles | Metrics

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Searchable Encryption Scheme of Genomic Data Based on Suffix Tree QIN Shi-yue， ZHOU Fu-cai， LIU Lu 2019, 40 (4):  461-466.  DOI: 10.12068/j.issn.1005-3026.2019.04.002 Abstract ( 574 )   HTML   PDF (476KB) ( 661 )   A searchable encryption scheme that specifically supports genetic data was proposed to protect users from privacy risks. The existing searchable encryption schemes only support keywords search， they cannot be applied to genetic data without keywords. So， a security index using cryptographic primitives such as suffix trees and pseudo-random functions was constructed to implement arbitrary substring searches for ciphertext genomic data. The safety proof indicated that the method satisfies the dynamic adaptive security， and the efficiency is evaluated by both theoretical analysis and real data. This scheme can perform efficient and safe arbitrary substring search on genomic data，protect data integrity and privacy and has broad application prospects in the environment of personalized medical popularization. References | Related Articles | Metrics

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Hybrid Recommendation Algorithm Based on Timed-HITS and Collaborative Filtering SUN Yan-rui， CHEN Yue 2019, 40 (4):  467-473.  DOI: 10.12068/j.issn.1005-3026.2019.04.003 Abstract ( 586 )   HTML   PDF (412KB) ( 628 )   The product recommendation effect was affected by the trust relationship among users， the preference interest for goods and the time factor. These factors were introduced to the basic HITS algorithm， and the HITS algorithm was improved. The user preference interest matrix was also improved， which uses implicit data to estimate users′ preference for goods using logistic regression algorithm. The situation with zero score gives different preference values， which is more consistent with reality. A hybrid recommendation model was proposed by combining the improved HITS algorithm with the collaborative filtering algorithm， and users were divided into active users and inactive users for recommendation. The proposed algorithm was tested using the Movielens data set， the results showed that the algorithm could generate better recommendation result in sparse data sets and cold-start situation， and it outperforms user-based collaborative filtering algorithm. References | Related Articles | Metrics

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Breast Tumor Classification Based on Bilateral TIC Quantitative Features SUN Hang， LI Hong， LIU Si-qi， ZHANG Wei 2019, 40 (4):  473-477.  DOI: 10.12068/j.issn.1005-3026.2019.04.004 Abstract ( 667 )   HTML   PDF (634KB) ( 644 )   An effective bilateral quantitative analyzing method for breast tumor classification was proposed based on the time intensity curve(TIC) of dynamic contrast enhanced magnetic resonance imaging(DCE-MRI). The breast lesion region in DCE-MRI images was extracted using three-dimensional region growing algorithm， and 29 features were extracted based on the TIC curves of the ROI corresponding to the lesion area and its contralateral mammary gland. The two-sided difference feature parameters were defined， and 7 effective features after screening by the sequential floating forward selection(SFFS) method were obtained. The support vector machines(SVM) was used for classification， and the classification results were obtained on the basis of cross-validation method for feature training. A hundred and twelve retrospective cases(67 benign， 45 malignant) were chosen randomly， and the average classification accuracy is 88.39%.The experimental results showed that this method has a high accuracy rate for breast tumor classification， and is of great value for assisting doctors in differential diagnosis of breast tumor. References | Related Articles | Metrics

Materials & Metallurgy

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Effect of Cooling Process Parameters on Microstructure and Mechanical Properties of Marine Engineering H-Beam Steel DONG Chun-yu， ZHAO Xian-ming， ZHOU Xiao-guang， ZHAO Jing-li 2019, 40 (4):  478-482.  DOI: 10.12068/j.issn.1005-3026.2019.04.005 Abstract ( 679 )   HTML   PDF (1739KB) ( 640 )   The effect of different process parameters on the microstructure and mechanical properties of marine engineering H-beam steel(SM490YB) were studied through the hot rolling and ultra-fast cooling experiments. The mechanisms of strengthening and toughening of SM490YB steel were analyzed. The results showed that with decreasing temperature of the final cooling， the contents of bainite and acicular ferrite increase at the same position in thickness direction of the tested steel， in contrast to those of polygonal ferrite and pearlite. Moreover， the strength and low-temperature toughness of the steel increase with the decrease of the final cooling temperature. When the final cooling temperature is 480℃ and the heat return temperature is 554℃， the performance of mechanical property is the best. The increase of the cooling rate can improve the strength of the tested steel， however the excessive cooling rate can deteriorate the toughness. References | Related Articles | Metrics

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Production Technology of Low-C Medium-Mn Q690F High Strength and Toughness Mid-Thick Steel Plate QI Xiang-yu， ZHU Xiao-lei， HU Jun， DU Lin-xiu 2019, 40 (4):  483-487.  DOI: 10.12068/j.issn.1005-3026.2019.04.06 Abstract ( 605 )   HTML   PDF (2219KB) ( 711 )   The thermomechanical control process(TMCP) and heat treatment test were conducted on low-C medium-Mn Q690F high strength and toughness mid-thick steel plate. The microstructure of the tested steel was analyzed and the tensile and impact properties were measured. The strengthening and toughening mechanisms were discussed. The results showed that the microstructure of the tested steel is a layered structure composed by sub-micrometer tempered martensite and reverse transformation austenite.The yield strength， tensile strength，elongation， and-60℃ impact energy of the tested plate at 1/4 thickness are 725MPa， 840MPa， 27.7%， 130J， respectively. The strain hardening caused by transformation induced plasticity(TRIP)from the reversed austenite is the main strengthening mechanism. The TRIP effect which absorbs a large amount of strain energy， delays the necking and increases the uniform elongation is considered as the main mechanism for plasticizing. Furthermore， the TRIP effect can increase the energy of the crack initiation and propagation effectively， it is also regraded as the main toughening mechanism. References | Related Articles | Metrics

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Numerical Simulation and Fracture Prediction of Incremental Sheet Forming of Metals LI Jun-chao， XIE Feng， ZHAO Ze， GONG Peng-cheng 2019, 40 (4):  488-494.  DOI: 10.12068/j.issn.1005-3026.2019.04.007 Abstract ( 684 )   HTML   PDF (3612KB) ( 830 )   In order to solve the problems in the fracture prediction of incremental sheet forming of metals，in which the prediction strongly depends on the strain path and a real-time prediction cannot be achieved， a numerical model has been built. To perform that， the Yu Zhongqi ductile fracture criterion was firstly added into ABAQUS software through the interface subroutine of the VUMAT for DC56D+Z steel. Then， the uniaxial tensile and incremental forming processes were simulated by the new user-defined model and ABAQUS built-in Von Mises model， respectively. Finally， according to the results of finite element simulation， the critical fracture integral value I of the incremental forming model under the Yu Zhongqi ductile fracture criterion can be reduced reversely based on the actual experimental results. The results show that the calculated stress and strain from the two models have the same order of magnitude and similar distribution， which prove the validity of the subroutine. The maximum fracture integral value I in the simulated sheet forming process appears on the side wall of the workpiece， which is consistent with the experimental ones. The critical fracture integral value I=17 can be used as an effective way to predict the fracture in the incremental sheet metal forming process. References | Related Articles | Metrics

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Effects of Laser Cladding Parameters on Microstructure and Properties of Gradient Cladded Coating on 45# Steel XU Ni-jun， LIU Chang-sheng， FENG Xin-yu， SUN Ting 2019, 40 (4):  495-499.  DOI: 10.12068/j.issn.1005-3026.2019.04.008 Abstract ( 677 )   HTML   PDF (2310KB) ( 781 )   The effects of laser cladding power， scanning speed and cladding materials on the microstructure and wear resistance of the cladded coating on 45# steel were investigated. The results show that the gradient cladded layer is continuous without the defects of crack pores and is metallurgically bonded to the 45# steel matrix.The microstructure of the cladded layer are characterized by dendritic crystals， equiaxed crystals and other rapid solidification structures， which is composed of α-Fe， CrNiFe-C and Cr7C3. The microhardness of the cladded layer is gradient， and the surface hardness of the cladded layer and the transition layer are 7.48GPa and 5.52GPa， respectively， which is 3.74 and 2.76 times of the hardness of the substrate.Therefore， the laser cladding technology can significantly improve the wear resistance of 45# steel. References | Related Articles | Metrics

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Recycle Aluminum Hydroxide from Residue of Vacuum Aluminothermic Reduction Lithium Process DI Yue-zhong，PENG Jian-ping，WANG Yao-wu，FENG Nai-xiang 2019, 40 (4):  500-504.  DOI: 10.12068/j.issn.1005-3026.2019.04.009 Abstract ( 630 )   HTML   PDF (753KB) ( 733 )   When lithium was produced in the process of aluminothermic reduction LiAlO2 clinker in vacuum condition where the clinker was prepared by calcined mixture of lithium carbonate， alumina and calcium oxide at normal atmosphere， the reduction residue containing CaO·Al2O3 and 12CaO·7Al2O3 was obtained. In order to recycle the reduction residue， the residue was firstly leached with a mixture solution of sodium hydroxide and sodium carbonate， and then aluminum hydroxide was produced by decomposing the leaching solution with carbon dioxide. The effects of leaching temperature， leaching time， particle size， sodium carbonate concentration， sodium hydroxide concentration and lithium reduction rate on leaching rate of alumina were investigated. The results showed that the leaching rate of alumina is 80.73% under the conditions of the particle size distribution d90 of 74μm，the leaching temperature of 95℃， the leaching time of 120min， the Na2CO3 concentration of 240g/L and NaOH concentration of 8.9g/L， when the residue is from the reduction lithium process with a reduction rate of 97%. The average particle size and the whiteness of aluminum hydroxide obtained by carbonation precipitation are 6.50μm and 96.9， respectively. References | Related Articles | Metrics

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Non-premixed Combustion of Parallel Multiple Jets in Scarfing Process LI Yi-ming， LI Bao-kuan， QI Feng-sheng 2019, 40 (4):  505-509.  DOI: 10.12068/j.issn.1005-3026.2019.04.010 Abstract ( 568 )   HTML   PDF (4228KB) ( 704 )   A remote-controlled combustion test bench was set up to investigate the non-premixed combustion process of natural gas and oxygen， and the temperature distribution of multiple jets combustion flame was analyzed by the indirect temperature measurement. The Realizable k-ε turbulence model was used to study the flow field characteristics of parallel multiple jets， and the equilibrium chemical reaction model was used to study the non-premixed combustion process of jet. The numerical results have good agreement with those from the experiments. The results indicateed that the entraining and merging behaviors of multiple jets could promote the combustion action. The parallel 45 jets tend to form dual-jet combinations near the nozzle exit. Interactions and re-combinations of the jets could take place during further flowing and eventually form 3 strong flames in the downstream. References | Related Articles | Metrics

Mechanical Engineering

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Design and Dynamic Simulation of Magneto-Rheological Elastomer Torsional Dynamic Vibration Absorber LIU Hui， ZHOU Han， GAO Pu， XIANG Chang-le 2019, 40 (4):  510-515.  DOI: 10.12068/j.issn.1005-3026.2019.04.011 Abstract ( 634 )   HTML   PDF (1566KB) ( 710 )   A semi-active torsional dynamic vibration absorber(DVA) with a magneto-rheological elastomer(MRE) as the core intelligent control element was developed. Based on the principle of DVA in torsional direction， the structure of the DVA was designed. The magnetic circuit simulation analysis of the absorber was carried out to ensure a strong closed magnetic field， which can effectively control the stiffness of MRE. The dynamics simulations of the DVA were carried out with the finite element software，which ensures that the natural frequency of the DVA can effectively follow the external excitation frequency to achieve the vibration absorption effect. The vibration absorber was installed on the corresponding position of the transmission system， and the simulation analysis of the system vibration response shows that the DVA can effectively reduce the transient fluctuation torque of the transmission system. The as-proposed MRE semi-active DVA provides a new idea for vibration reduction of rotating mechanical systems. References | Related Articles | Metrics

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Theoretical and Experimental Study on Vibration Characteristics of FDM Thin Plates JIANG Shi-jie， SHI Yin-fang， SIYAJEU Yannick， WEN Bang-chun 2019, 40 (4):  516-520.  DOI: 10.12068/j.issn.1005-3026.2019.04.012 Abstract ( 623 )   HTML   PDF (588KB) ( 799 )   Fused deposition modeling(FDM) is a rapid prototyping technology that can directly print parts with complex geometrical shapes. However， it is hard to compare with the traditional processing methods in terms of vibration property， and a more practical analysis of vibration characteristics is needed. Therefore， a theoretical modeling method of vibration characteristics of the FDM 3D printed was proposed for the first time. The FDM sheet under the cantilever boundary conditions was taken as the research object. Based on the classical laminated plate theory， the vibration mode function was represented by the bidirectional beam function combination method， and the inherent characteristics of the composite thin plate were obtained by the Ritz method.The inherent characteristic test system of the FDM 3D printed plate was built， and the natural frequency and mode shape of the thin plate sample were obtained. The calculation and experimental results verify the correctness and reliability of the theoretical calculation method. References | Related Articles | Metrics

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Dynamic Cutting Force Measurement Test and Prediction of Time Series Model for Machine Tools ZHANG Bao， ZHAO Chun-yu， WEN Bang-chun 2019, 40 (4):  521-526.  DOI: 10.12068/j.issn.1005-3026.2019.04.013 Abstract ( 563 )   HTML   PDF (856KB) ( 734 )   In order to obtain the dynamic cutting force， the experiment of 12Cr18Ni9 revolving parts was carried out on the NC machine tool ETC1625P. The location information of the cutter in the two orthogonal directions of the cutting plane was obtained by the real-time signal acquisition system. Meanwhile， the KISTLER sensor was installed on the tool head of the machine tool to measure the real-time cutting forces in three cutting directions. The experimental data shows that volatility change of the cutting force was produced in the feed direction with the displacement. In order to study the complex nonlinear relationship between the cutting force and cutting parameters， the prediction of dynamic cutting force is realized by time series analysis modeling. The cutting force error is analyzed， and the prediction accuracy obtained meets the requirements. References | Related Articles | Metrics

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Leakage Model of Contacting Mechanical Seal Based on Fractal Theory LI Xiao-peng， YANG Ze-min， WANG Lin-lin， YANG Yu-xing 2019, 40 (4):  526-530.  DOI: 10.12068/j.issn.1005-3026.2019.04.014 Abstract ( 697 )   HTML   PDF (490KB) ( 767 )   At present， most studies about the seal are based on the assumption that the seal surface topography and friction conditions are changeless. The influence of the seal surface topography on the leakage is mostly ignored as well as the effect of the microscopic perspective. Based on the fractal theory， the contact between surfaces of dynamic and static rings was simplified to the contact between rough surface and the ideal rigid plane， and a mechanical seal leakage model was established. The effects of fractal parameters， the surface unit load and material parameters on leakage rate were studied to obtain that the mechanical seal fractal dimension D and the end face specific load p○g were inversely proportional to the leakage amount Q. The characteristic length scale parameter G and the comprehensive elastic modulus E were proportional to its leakage amount Q. The calculated leakage rate and experimental data verify the accuracy of the model. References | Related Articles | Metrics

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Optimization Design of Heavy-Duty Tractor Based on Sub-structure Modal Synthesis Method LI Bo-bo， YUAN Hui-qun， WANG Guang-ding， SUN Hong-yun 2019, 40 (4):  531-537.  DOI: 10.12068/j.issn.1005-3026.2019.04.015 Abstract ( 566 )   HTML   PDF (1069KB) ( 490 )   Taking a heavy-duty tractor as the research object and the sub-structure modeling method was used to establish a reduced vehicle dynamics simulation model including each suspension component and load. The intrinsic characteristics of the model were analyzed and compared with the inherent characteristics of the vehicle model established by the traditional modeling method. The correctness of the model was verified. The sub-structure modal synthesis method was used to study the dynamic response of the vehicle， and compared with the actual vehicle test results. Combined with six sigma optimization design theory and the robustness of heavy tractors was optimized. The results showed that the as-proposed dynamic simulation model can effectively simulate the dynamic characteristics of the vehicle. Under the premise of satisfying the design life， the heavy-duty tractor has improved the anti-interference ability of the system and realized the lightweight of the whole vehicle. References | Related Articles | Metrics

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Influence of Laser Cladding Process Parameters on Morphology of Cladding Layer and Its Optimization YU Tian-biao， SONG Bo-xue， XI Wen-chao， MA Zhe-lun 2019, 40 (4):  537-542.  DOI: 10.12068/j.issn.1005-3026.2019.04.016 Abstract ( 883 )   HTML   PDF (1032KB) ( 1363 )   The IPG-500 laser was used to implement laser cladding on 45# steel. The influence of process parameters on the morphology of the cladding layer was studied， and the key factors affecting the morphology of the cladding layer were obtained by range analysis. On this basis， the gray correlation degree was used to analyze the correlation between the quality of the cladding layer and the ideal cladding layer quality under different parameter combinations， and the optimal combination of laser cladding process parameters can be found. The results show that the laser power and scanning speed are the main factors affecting the morphology of the cladding layer， and the optimized cladding layer is obtained under the conditions of laser power of 400W， scanning speed of 7mm/s and powder feeding rate of 0.7r/min， which provides theoretical support for the selection of laser cladding process parameters. References | Related Articles | Metrics

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Reliability Sensitivity Analysis of Thin-Walled Components Milling Machining HUANG Xian-zhen ， ZANG Yun-fei， SONG Zeng-wang， JIAO Bao-long 2019, 40 (4):  543-547.  DOI: 10.12068/j.issn.1005-3026.2019.04.017 Abstract ( 568 )   HTML   PDF (594KB) ( 614 )   A stability and surface position error model for the thin-walled components milling was established by using a single frequency method. The Kriging method was used to analyze the reliability sensitivity of the stability and surface position error of thin-walled components milling， and to evaluate the influence of milling parameters on the stability and surface position error of thin-walled components milling. The results show that the system reliability increases with the increase of damping ratio and y direction stiffness of the thin-walled components milling system. The system reliability decreases with the increase of tangential force coefficient， natural frequency， radial invasion ratio and axial cutting depth. The radial force factor and feed per tooth have less impact on the system. The research results may provide reasonable theoretical basis for high speed milling of thin-walled components. References | Related Articles | Metrics

Resources & Civil Engineering

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Grinding Technical Efficiency Prediction Model Based on Matlab and Particle Swarm Optimization ZHOU Wen-tao， HAN Yue-xin， LI Yan-jun， YANG Jin-lin 2019, 40 (4):  548-552.  DOI: 10.12068/j.issn.1005-3026.2019.04.018 Abstract ( 677 )   HTML   PDF (479KB) ( 739 )   The effect of grinding time， dry ore mass fraction and filling rate on the grinding technical efficiency of cassiterite polymetallic sulfide ore were studied. The results showed that the grinding efficiency corresponding to the binary structure of cassiterite and sulfide ore is the best when the grinding time is 8min， the dry ore mass fraction is 65%， and the filling rate is 42%. A grinding technical efficiency prediction model was established by using the generalized regression neural network(GRNN) program of Matlab. The model parameters were optimized by the particle swarm optimization. The applicability and reliability of the model were verified by experiments. References | Related Articles | Metrics

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Application of Numerical Manifold Displacement Method in Crack Propagation of Rock Mass WANG Shu-hong， QIU Wei， GAO Hong-yan， ZHANG Zi-shan 2019, 40 (4):  552-556.  DOI: 10.12068/j.issn.1005-3026.2019.04.019 Abstract ( 532 )   HTML   PDF (777KB) ( 593 )   Based on the finite element triangle mesh， the changing of manifold elements in crack propagation process was studied in depth， and the continuous and discontinuous unified processing of the numerical manifold method are interpreted from the perspective of geometric mesh. The first-order coverage function was used to derive the weight function expression of numerical manifold algorithm， so that the local displacement function can be established. Through the numerical manifold calculation program， the crack tip displacement was obtained， and the tip stress intensity factor was calculated and verified by the classical cracked plate model. The numerical result is in good agreement with the analytical solution， which proves the numerical manifold method is accuracy and can be used as a new numerical solution for solving the tip stress intensity factor in the crack propagation process. References | Related Articles | Metrics

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Influence of Staging Ore Volume on Boundary Optimization GU Xiao-wei， ZHANG Wei-feng， WANG Qing， XU Xiao-chuan 2019, 40 (4):  557-562.  DOI: 10.12068/j.issn.1005-3026.2019.04.020 Abstract ( 607 )   HTML   PDF (533KB) ( 585 )   The cone elimination method was used to generate the maximum boundary based on established numerical model of ore deposits considering slope angle and technical economic parameters.On the basis of the geological optimum candidate boundary sequence produced in the maximum boundary， five groups of staging ore volume were set up. By comparing the staging number， the amount of ore and rock in staging boundary， the net present value and the time span of each stage， the influence of staging ore volume on boundary optimization was analyzed. The optimization results showed that the lower limit of the staging ore volume remains unchanged and the upper limit increases， the staging number decreases from 9 to 8.The fluctuation of the mining amount and the rock stripping amount in the staging boundary mainly occurs in the first few stages. The total net present value has been increasing，however the increase is gradually decreasing. The lower limit of the staging time span is unchanged， the upper limit is gradually increasing. According to the total net present value and the staging time span， staging ore volume in 6~9a or 6~10a is more suitable to improve economic efficiency. References | Related Articles | Metrics

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Fast Probability Tomography of Gravity Anomaly Data Based on Taylor Series HOU Zhen-long ， WANG En-de 2019, 40 (4):  563-568.  DOI: 10.12068/j.issn.1005-3026.2019.04.021 Abstract ( 703 )   HTML   PDF (1926KB) ( 656 )   In order to improve the data tomography efficiency in the gravity exploration，gravity anomaly data from the geophysical exploration were processed by fast three-dimensional tomography. The algorithm of Taylor series was used for the prism unit based on the related probability tomography theory， in which the calculation model of anomaly data were redefined to obtain new geometric functions. The tomography method reduces the calculation amount and the number of iterations by series expansion and integral. In the theoretical model test， it is proved that the proposed method has good tomography ability and anti-noise characteristic. The efficiency analysis shows that the algorithm can greatly shorten the calculation time of the geometric function matrix and improve the imaging efficiency. Fast tomography was applied for the real gravity anomaly data of Vinton Dome， the location of geological body could be shown well， which verifies the algorithm feasible. References | Related Articles | Metrics

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Effect of Citric Acid on Entrainment Behavior of Fine Chlorite YANG Bin， YIN Wan-zhong， FU Ya-feng， YAO Jin 2019, 40 (4):  569-574.  DOI: 10.12068/j.issn.1005-3026.2019.04.022 Abstract ( 713 )   HTML   PDF (1301KB) ( 712 )   Flotation tests， Zeta potential measurements， infrared spectrum analyses， EDLVO calculations and SEM analyses were used to investigate the effect of citric acid on entrainment behavior of fine chlorite in hematite reverse flotation. Flotation results illustrated that citric acid promotes entrainment behavior of fine chlorite， and is conducive to removing chlorite in concentrate. Zeta-potential tests and infrared spectrum analyses indicated that adsorption of citric acid on the surfaces of chlorite and hematite increases their electronegativity and enhances the electrostatic repulsion between hematite and chlorite particles. EDLVO calculations demonstrated that the attraction between hematite and fine chlorite is transformed into repulsion after interacting with citric acid， and the calculation results are consistent with those of SEM. References | Related Articles | Metrics

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Adsorption Thermodynamics and Kinetics of Bornite Using Sodium Butyl Xanthate as Collector in Flotation SUN Qian-yu， YIN Wan-zhong， ZHU Zhang-lei， YAO Jin 2019, 40 (4):  574-579.  DOI: 10.12068/j.issn.1005-3026.2019.04.023 Abstract ( 619 )   HTML   PDF (710KB) ( 605 )   The flotation performance of bornite was investigated， and the adsorption mechanism of sodium butyl xanthate(NaBX) on the bornite surface was studied by using the adsorption measurement， infrared spectroscopic analysis， adsorption kinetics and thermodynamic calculation. The pH value ranging from 5 to 9 is favorable for highter floatability， and the adsorption conforms to the multimolecular layer adsorption of Freundlich model. When the pH value is 12， the floatability is poor， and the adsorption belongs to monolayer adsorption of Lamgmuir model. The adsorption of NaBX on the bornite surface conforms to second-order kinetic equation， and it is a spontaneous chemical adsorption process. The thermodynamic calculation shows that the adsorption reaction at pH 9 is easier than that at pH 12. Infrared spectroscopic analysis shows that the adsorption species of NaBX on the surface of bornite contain Cu(BX)2，Fe(BX)3 and(BX)2 when the pH ranges from 5 to 9， while there is only Cu(BX)2 when pH is 12. References | Related Articles | Metrics

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Mineralogy Features of Micro-fine Ilmenite in Panxi Region SHEN Shuai-ping， YUAN Zhi-tao， MA Long-qiu， MENG Qing-you 2019, 40 (4):  580-584.  DOI: 10.12068/j.issn.1005-3026.2019.04.024 Abstract ( 620 )   HTML   PDF (684KB) ( 732 )   Based on the typical process mineralogy method， the chemical composition， mineral composition， size distribution and dissemination characteristics of the micro-fine ilmenite sample were investigated through chemical analysis， XRD，SEM and MLA， and then the sample separation features were analyzed and discussed. The research showed that the valuable element Ti of 67.04% occurs in the form of ilmenite， and the primary gangue minerals are titanaugite， chlorite and feldspar. Particle size below 19μm reaches 74.33% in the sample， among which the size distribution of each mineral has a significant difference， and the valuable minerals are finer than that of the gangue minerals. The ilmenite liberation degree is 90.43%， which is closely interlocked with titanaugite. The results provide the basis for the high-efficiency recovery of the micro-fine ilmenite. References | Related Articles | Metrics

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Reliability Evaluation on Stay Cables Based on Cloud Theory LIANG Li， XING Guan-hua， REN Yi-peng， SUN Shuang 2019, 40 (4):  585-589.  DOI: 10.12068/j.issn.1005-3026.2019.04.025 Abstract ( 526 )   HTML   PDF (456KB) ( 675 )   In order to accurately assess the reliability of the stay cables， which are vulnerable and difficult to repair， and to ensure a safety and comfort driving， a reliability evaluation method on stay cables based on cloud theory was proposed. According to the mechanical characteristics and common defects of cables， a reliability evaluation index system of stay cables was established by selecting indexes using the extreme stress value， amplitude of constant load， stress amplitude， basic frequency， service time， cracking degree of PE sheath and integrity of the damping system. Then the weight cloud models were established according to experts′ opinions， and the group decision weights were obtained from the concept extension of general concept tree. Finally， a weighted summary was conducted on the average certainty of assessment grade for each index and the weight cloud model. The certainty cloud models of each reliable grade thus can be obtained to determine the final result. The rationality and maneuverability of the method were verified by comparing the specification evaluation results with the actual defect condition. References | Related Articles | Metrics

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Flexural Performance of Damaged Prestressed Reinforced Concrete Beams Strengthened with Near Surface Mounted CFRP Strips YANG Jia， WANG Lian-guang， HOU Wen-yu 2019, 40 (4):  590-595.  DOI: 10.12068/j.issn.1005-3026.2019.04.026 Abstract ( 556 )   HTML   PDF (705KB) ( 663 )   In order to investigate the flexural performance of damaged prestressed reinforced concrete(PRC) beams strengthened with near surface mounted(NSM) carbon fiber reinforced polymer(CFRP) strips under overloading， bending tests of six PRC beams were carried out. The failure mode， bearing capacity and stiffness of PRC beams strengthened with NSM CFRP strips were studied. The influences of the number of overloading cycles， overloading amplitude and sustaining load on the performance of strengthened beams were also evaluated. The experimental results indicated that compared with un-strengthened beam， the flexural capacity and stiffness of the strengthened beams can be enhanced obviously. The ultimate loads are increased by 7% to 15%. There are little influences on ultimate bearing capacity of the strengthened beams caused by the cycle number， the overload amplitude and the sustaining load， while the overload amplitude and the sustaining load affect the stiffness of the strengthened beams. A calculation formula of bearing capacity is established， and the theoretical values agree well with the experimental values. References | Related Articles | Metrics

Management Science

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Dynamic Volatility Spillover Network of Chinese Financial Institutions HUANG Wei-qiang， LI Fang， YAO Shuang 2019, 40 (4):  596-601.  DOI: 10.12068/j.issn.1005-3026.2019.04.027 Abstract ( 598 )   HTML   PDF (345KB) ( 593 )   A dynamic volatility spillover network of financial institutions was constructed on the basis of the VAR-GARCH-BEKK model， whose associated topology indicators were analyzed， and the dynamic correlation laws of volatility spillover between financial industries were investigated. The results showed that the volatility spillover levels are more stable in the bank industry than those in other industries. During most of the periods， the banks and security companies form independent correlated communities. From the perspective of receiving volatility spillover， the security industry has the strongest average systemic correlation， and the trust industry has the strongest average inter-industry correlation. From the perspective of sending volatility spillover， the insurance industry has the strongest average inter-industry correlation， and the average systemic correlations are not significantly different among different industries. From the perspective of network embeddedness， the trust industry has the strongest average systemic correlation and inter-industry average correlation， whose embeddedness is the greatest. References | Related Articles | Metrics

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Effect of Delisting System Changes on Listed Companies′ Earnings Management Behavior CHENG Fu， SUN Shi-min， ZHANG Jia-ye 2019, 40 (4):  602-608.  DOI: 10.12068/j.issn.1005-3026.2019.04.028 Abstract ( 705 )   HTML   PDF (515KB) ( 765 )   Taking the 2012a Shanghai and Shenzhen Stock Exchange′s revision of the delisting system as the entry point， the 2008~2015a Shanghai-Shenzhen A-share main board listed companies are selected as the research samples and the effect of delisting system changes on the earnings management behavior of listed companies were empirically tested by using the earnings distribution method and multiple regression method. The results showed that after the delisting system changes， the behavior of avoiding negative net profits decreases slightly， but the behavior of avoiding negative net assets increases significantly. The delisting system changes induce the earnings management behavior of avoiding operation revenues lower than 10 million yuan， and the listed companies′ accrual earnings management behaviors decrease significantly， but their real earnings management behaviors such as sales manipulation， expense manipulation and production manipulation increase significantly. References | Related Articles | Metrics