Journal of Northeastern University(Natural Science)

Reflective Gas Sensor Based on Hollow Core Photonic Crystal Fiber

QIAN Xiao-long， ZHANG Ya-nan， PENG Hui-jie， WU Qi-lu

2017, 38 (12): 1673-1676. DOI: 10.12068/j.issn.1005-3026.2017.12.001

Abstract ( 704 )

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In order to enhance the gas measurement sensitivity， a reflective optical fiber gas sensing technology was proposed using photonic crystal fiber (PCF). Firstly， the harmonic detection technology of broadband source was used in combination with the practical application demands. Then， aimed at the problems of coupling between hollow core PCF and single mode fiber， and the long infiltrating time of measured gas， a new measured gas chamber was designed， which integrated seal， fixation and connection. Finally， taking acetylene gas as an example， the sensing properties of the proposed sensor were measured. Experiment results demonstrated that the minimum detectable concentration could be as accurate as 0.02%， and the maximum relative error was 1.39%. The proposed technology can further promote the applications of PCF in gas sensing， and lay the theoretical and experimental foundations for its practical applications.

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Inductance Coupling Analysis of Novel Isolated Modular Permanent Magnet Machine

YAN Shi-jie， XU Xiao-min， YAN Wei-hang， GAO Wen-zhong

2017, 38 (12): 1677-1681. DOI: 10.12068/j.issn.1005-3026.2017.12.002

Abstract ( 690 )

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Aiming at the problems of reliability and maintainability during the operation of high power machine， the structure for a novel independent modular Permanent Magnet Synchronous Machine (PMSM) was designed. The mathematical model of modular PMSM was established and the inductance coupling of three-phase winding between the neighboring modules was analyzed. This machine was composed of detachable stators， whose modular machines could operate separately. Through the proposed concept of parent modules and sub-modules， parent modules were recombined with sub-modules to achieve the inductance decoupling between modules. Meanwhile， by exchanging the winding phase of sub-modules in parent module， the problem of asymmetric three-phase winding parameters caused by the discrete modules was also solved. The feasibility of structure for this machine was proved by the results of finite element analysis.

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Research on High-Order Dielectrophoresis for Non-Spherical Cell Using Effective Moment Method

HU Sheng， LYU Jiang-tao， SI Guang-yuan

2017, 38 (12): 1681-1685. DOI: 10.12068/j.issn.1005-3026.2017.12.003

Abstract ( 701 )

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Simulation of cells exerted by the dielectrophoresis plays an important role in the micro-manipulation fields. Traditional solution to dielectrophoretic force experienced cell is ideally considered as a regular sphere calculation. The effect of high-order dielectrophoretic forces are often neglected， which will cause greater error between molecular dynamics and experimental observation. Therefore， the effective moment method was used to solve high-order dielectrophoresis for both ellipsoid and erythrocyte in this paper. It is effective for classical Pohl expression to predict spherical cell exerted by dielectrophoresis. However， odd numerical moments are closely related to their shape such as ellipsoids and erythrocyte are non-zero from 1 to 9 order dipole moments. The dielectrophretic force of erythrocyte similar to oblate spheroid with indented side approximates the ellipsoid with eccentricity ratio 1∶5. The results were in good agreement with Ogbi’s reports.

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Hybrid Multi-step Markov Location Prediction Based on GPS Trajectory Data

LI Sheng-zhi， QIAO Jian-zhong， LIN Shu-kuan， YANG Di

2017, 38 (12): 1686-1690. DOI: 10.12068/j.issn.1005-3026.2017.12.004

Abstract ( 694 )

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Recently， with the wide use of mobile devices and location technology， LBS (location based service) becomes research hotspot. Location prediction is a primary research aspect of LBS. The location prediction based on GPS trajectories was researched. Markov model can represent temporal data well， so it was used in location modeling and prediction. In Markov based location prediction， 1-order Markov model cannot employ trajectory data sufficiently， so the prediction precision is low. The state space of multi-order Markov model will increase rapidly with the order number increasing. For these problems， a novel location prediction method was proposed based on hybrid multi-step Markov model， which transformed the original GPS trajectories into region trajectories. On this basis， all multi-step Markov models were merged. In the course of it， an Adaboost frame based method generating the influence coefficient of each multi-step model was presented. So， the prediction precision was improved， and the state space did not increase. The experiments on real GPS trajectory data show the effectiveness of the location prediction method proposed by the paper.

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Clique Percolation Based Local Fitness Method for User Clustering in Telecommunication Network

LI Jie， WANG Xing-wei， GUO Jing， YU Chao

2017, 38 (12): 1691-1696. DOI: 10.12068/j.issn.1005-3026.2017.12.005

Abstract ( 709 )

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To expand new business， the telecommunication companies need to understand their users deeply. So the data of the user behavior was analyzed in the telecommunication system by using the big data analyzing technology. A clique percolation based local fitness method was proposed for weighted network algorithm (CLFMw) based on the call logs of users in the telecommunication network. The social relationships were established from all of the call connections. Based on the local fitness method (LFM) and the clique percolation method (CPM)， the user group was constructed with CLFMw algorithm. According to the massive data sets of the telecommunication system， parallelization design was used based on the MapReduce programming model. Finally， the group construction algorithm is verified by the simulation data set and the real data set for China Mobile. The experimental results show that this method is well performed but also feasible and effective.

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Effect of Ultrafast Cooling on Preventing Abnormal Microstructural Banding at Centerline of Steel Plate

YE Qi-bin， XIE Qian， LIU Zhen-yu， WANG Guo-dong

2017, 38 (12): 1696-1701. DOI: 10.12068/j.issn.1005-3026.2017.12.006

Abstract ( 767 )

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The abnormal microstructural banding at centerline was compared among three steel plates of 355 MPa grade using OM， TEM and EPMA， and the effects of ultrafast cooling (UFC) and finish rolling temperature (FRT) were discussed. It was found that UFC was effective to suppress banding in centerline segregation zones， as the bands were entirely disappeared in UFC steel with FRT at 950℃ (UC1 steel)， comparing with the feeble bands in UFC steel with FRT at 900℃(UC2 steel). In contrast， severe bands consisting of martensite/austenite constituent (M/A) were observed in a conventional laminar-water cooled steel (LC steel)with a cooling rates of 15℃/s. The thermodynamic calculation showed that the equilibrium temperature of austenite-to-ferrite transformation could be reduced by 144℃ in elements-rich centerline zone， increasing the critical cooling rate to 8℃/s for avoidance of banding. The simulated temperature indicated the cooling rate of 12.1 and 13.4℃/s at the mid-thickness of UC1 and UC2 steels， respectively， comparing with that of 5.5℃/s for LC steel. Therefore， UFC provides sufficient cooling capability for suppressing microstructural banding at plate centerline， while the lower FRT could offset the effect. In contrast， banding cant be prevented by exploring laminar-water cooling because of its relatively low cooling rate.

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Hot Deformation Behavior of Ti Microalloying Q390 High Strength Steel

ZHOU Xiao-guang， GUO Hong-he， JIANG Xiao-dong， LIU Zhen-yu

2017, 38 (12): 1702-1706. DOI: 10.12068/j.issn.1005-3026.2017.12.007

Abstract ( 868 )

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The hot deformation behaviors of Ti microalloying high strength steel with yield strength of 390MPa grade (Q390 steel) were investigated by a single-pass compression test. A mathematical model for deformation resistance and dynamic recrystallization of the experimental steel was established. The results show that deformation resistance increases gradually with the decrease of deformation temperature. The feature of stress-strain curves changes from dynamic recrystallization character to dynamic recovery character as increasing the strain rate. The activation energy of dynamic recrystallization for Q390 steel is about 257.142kJ/mol. The mathematical model has been proved to study the hot deformation behavior for Ti microalloying Q390 steel very effectively. Compared with the Q390 steel with the conventional chemical composition， the rolling force of the steel after Ti microalloying is small and dynamic recrystallization occurs more easily， which can facilitate the refining of austenite grain and improve the strength and toughness of the steel more substantially.

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Recrystallization Texture Evolution in Rolled Fe₈₁Ga₁₉ Alloy Thin Sheet

HE Zheng-hua， SHA Yu-hui， ZHANG Fang， ZUO Liang

2017, 38 (12): 1707-1711. DOI: 10.12068/j.issn.1005-3026.2017.12.008

Abstract ( 729 )

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The texture evolution and the magnetostriction response of the recrystallized Fe₈₁Ga₁₉ alloy thin sheet cold rolled with different reductions were investigated. It is revealed that the recrystallization texture is composed of Goss (110<001>) and γ (<111>//ND) texture， the characteristic of recrystallization texture is affected greatly by the reduction， attributed to the variation of deformed microstructure and texture. As the cold rolled reduction increases from 60% to 70%， Goss texture and magnetostriction value are enhanced by the increasing shear bands and strong 111<112> texture in deformed matrix. However， when the reduction is 80%， the Goss texture becomes weakened and the γ texture has been enhanced， resulted in a lower magnetostriction， because of the orientation deviation of nucleated grains in shear band caused by the texture variation in deformed matrix and shear bands， as well as more nuclear sites for recrystallized γ grains supplied by grain boundary with a higher storage energy.

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Effect of Mg on Carbon Fiber Stabilized Foaming Process and Pore Structure of Aluminum Foam

LI Min， CAO Zhuo-kun， YU Yang， YAO Guang-chun

2017, 38 (12): 1712-1715. DOI: 10.12068/j.issn.1005-3026.2017.12.009

Abstract ( 780 )

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Closed-cell aluminum foam with different amounts of Mg and carbon fiber were prepared by the method of molten body transitional foaming process， and the effect of Mg element on foaming process and pore structure of aluminum foams was discussed. The main results are as follows: when the addition of Mg element increases， the expansion rate of foam increases significantly and the range of the pore size distribution becomes broader， associated with the increasing number of small stomata. The microstructures of the inner and surface of the pore wall show that the pore wall can be smoother， thinner and more stable after adding Mg， because the surface tension of molten aluminum is reduced， the wettability between aluminum and oxide particles is improved and the gas release during the foaming process increases. As a result of Mg addition， it is achieved that the porosity of aluminum foam can be more than 90%.

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Research on Performance Optimization of Biomass Fuel for Sintering

LIU Chao， ZHANG Yu-zhu， XING Hong-wei， KANG Yue

2017, 38 (12): 1716-1721. DOI: 10.12068/j.issn.1005-3026.2017.12.010

Abstract ( 756 )

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Sintering is an important process during producing iron and steel in industry， however， it produces a large amount of high-temperature sintering flue gas which contains particulate matter， sulfur dioxide， nitrogen oxides， dioxins， etc. In order to reduce sintering pollutant， a new type of biomass fuel to replace the traditional coke fuel was prepared and the optimized preparation condition of the biomass fuel was studied by comparing the results from the experiments of biomass carbonization and biomass forming. The results show that the sawdust carbonization is divided into two stages: the suitable carbonization heating rate is 5℃/min at the stage of room temperature (25℃) to 400℃ and 20℃/min at the stage of 400℃ to 600℃. The sawdust optimal forming pressure is about 50MPa. By the comparison of the performance of optimized biomass fuel and traditional ore fuel， it is indicated that the effectiveness of biomass fuel can be close to that of ore fuel after improving the specific surface area， pore volume and fuel combustion performance.

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Influence of Gas Composition on HCl Removal Under None-dust and With-dust Conditions

TENG Ai-jun， HU Bin-sheng， GUI Yong-liang， XUE Xiang-xin

2017, 38 (12): 1721-1725. DOI: 10.12068/j.issn.1005-3026.2017.12.011

Abstract ( 639 )

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Using fixed-bed reaction method， the influence of blast furnace top gas composition on HCl removal by low temperature Ca-based antichlor under none-dust and with-dust conditions was studied through changing individual variable of the gas composition. The results showed that when the content of CO₂ in blast furnace top gas increased， the dechlorination efficiency decreased under both none-dust and with-dust conditions. However， when the content of CO and N₂ increased， the dechlorination efficiency improved substantially under both none-dust and with-dust conditions. It was also found that the dechlorination’s breakthrough time was 40~60min more than that under none-dust condition， while the capacity of reacted-chlorine increased 6% under with-dust one.

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Coke-Making with Modified Xinjiang Kubai Coals and Prediction the Cold Strength of Coke

ZHU Zi-zong， XIE Yang-yang， WU Qiang， SHI Guo-jing

2017, 38 (12): 1726-1730. DOI: 10.12068/j.issn.1005-3026.2017.12.012

Abstract ( 680 )

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The cokes with Xinjiang coking coals present high activity and poor quality， which can not be used in blast furnace. In order to decrease the coke reactivity index (CRI) and increase the coke strength after reaction (CSR)， a series of coke-making experiments using modified Xinjiang coals were carried out. By the thermo-gravimetric analysis on the blending coals， it is found that the modifying additive is primarily acted on the process of the formation of colloids and the polycondensation of semi-coke. The results show that the oxygenic groups of QM are mainly hydroxyl and alkylether determined by FTIR， while the carboxyl is rarely found. Based on the multiple linear regression analysis by SPSS17.0 software， a prediction model of the cold strength of coke was established， which used the parameters such as the volatile matter (V_daf) and caking index (G) as independent variable and used the crushing strength of coke (M25) and abrasive resistance (M10) as dependent variable. Hence， thermal properties and cold strength of coke can be controlled flexibly by this model.

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Analysis and Verification of Natural Characteristics of Fiber-Reinforced Thin Cantilever Plate

LI Hui， WU Huai-shuai， XUE Peng-cheng， WEN Bang-chun

2017, 38 (12): 1731-1736. DOI: 10.12068/j.issn.1005-3026.2017.12.013

Abstract ( 637 )

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This research combines theory with experiment to analyze and verify the natural characteristics of fiber reinforced composite thin plate under cantilever boundary condition. Firstly， based on two-dimension beam function method， the largest kinetic energy and strain energy of such composite plate with arbitrary fiber angle have been deduced， and the corresponding principles to analyze natural frequencies and modal shapes have been clarified. Then， the Matlab calculating program has been composed， and the specific analysis procedures of natural characteristics of fiber-reinforced thin cantilever plate are also proposed. Finally， TC500 fiber/epoxy composite plate is taken as the study object， and the frequency and shape results are measured based on the established test system of natural characteristics of such composite plate. The result frequencies calculated based on two-dimension beam function method has good consistent with the experimental results， and the related errors are within the range of 3.7%~9.7%. Besides， the first 5 modal shapes are also consistent with the measured shape results， thus the effectiveness of above method is verified.

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Study on Tensile Property of Fiber Metal Laminates

TONG An-shi， XIE Li-yang， BAI Xin， MENG Wei-ying

2017, 38 (12): 1736-1740. DOI: 10.12068/j.issn.1005-3026.2017.12.014

Abstract ( 714 )

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GLARE laminates are an advanced hybrid material system consisting of alternating layers of thin aluminium sheets and high strength glass fiber/epoxy composite layers. The unique combination of ductile aluminium layers with high strength composite layers results in a unique fiber-metal laminates (FMLs) with light weight， outstanding fatigue resistance， excellent impact resistance， flame resistance and corrosion properties. Mechanical tests were carried out on many kinds of GLARE laminates， and the influence of ply type on its static behavior has been studied. The mechanical properties of GLARE laminates were predicted using the metal volume fraction approach based on a rule of mixtures. The results show that good agreement is obtained between the model predictions and experimental results， while the fiber bridging effect needs to be considered to predict the fracture strength of some cross-ply GLARE laminates.

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Random Discrete Pulse Load Characteristics of Double Toothed Roll Crusher

YAO Hong-liang， CHANG Xi-zhen， JI Peng， WANG Gang

2017, 38 (12): 1740-1743. DOI: 10.12068/j.issn.1005-3026.2017.12.15

Abstract ( 821 )

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Firstly， the random discrete characteristics of material particles based on production capacity is discussed， the recursive formula of particle bulk density and expression of interval particle number under the condition of D3 distribution are presented. Secondly， the cutting resistance and the action time pulse load models are established， and put forward to use the ratio of the volume difference of the particle size required by the cutting ball material and the ratio of the volume of a single cut as a correction factor for the pulse load of the whole sphere material， and given the full pulse load model of the sphere material. Finally， the random discrete pulse load model of all the particles is established.

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Experimental Investigation of Operating Characteristics of Ejector in Steam Jet Refrigeration System

WANG Xiao-dong， FU Qiang， YI Shu， LI He

2017, 38 (12): 1744-1747. DOI: 10.12068/j.issn.1005-3026.2017.12.016

Abstract ( 728 )

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To determine the operating characteristics of ejector， evaluate the numerical model calculation accuracy and improve the ejector pump theory， an experimental system of small steam jet refrigeration was set up. The relationships between the steam jet pump performance and working steam pressure， suction pressure， the back pressure of the ejector were studied by using experimental method. The experimental results show that the secondary fluid flow rate and ejector coefficient (entrainment ratio， ER) increase firstly to the maximum and then decrease gradually with increasing the working steam pressure. With increasing suction pressure， the secondary fluid flow rate and the ER increase. The ER keeps a constant value in a certain range of back pressure and declines sharply when back pressure is bigger than the critical back pressure. It is important to understand the pumping characteristic of steam jet pump deeply based on the experimental research， and the experimental data can be used to optimize steam jet pump’s structure.

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Structure Design of a New Variable Stiffness Joint

FANG Li-jin， ZHOU Sheng-qi， WANG Yan

2017, 38 (12): 1748-1753. DOI: 10.12068/j.issn.1005-3026.2017.12.017

Abstract ( 1116 )

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Designing a stiffness joint structure that accords with the elbow parameters of the human body， make it better to help people in practical applications. Based on the parameters of the human elbow joint， a new variable stiffness joint structure is presented， which is in line with the human joint configuration. The new joint consists of leaf springs， planetary gear train and crank-slider mechanism. The sun gear and the ring gear are driven by two different motors， and the rotations of the planetary gears are turned into the movement of the sliders. The supporting positions of the leaf springs change as the sliders move， and the stiffness of the joint is adjusted. Compared with that of the other similar designs， the structure and the layout of the new joint presented are in much more accord with the configuration of the human joint， and the new joint could be applied to other joint designs.

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Parametrically Excited Vibration Characteristics of Cold Rolling Mill Under Nonlinear Dynamic Rolling Process

ＨOU Dong-xiao， WANG Xin-gang， ZHANG Hua-wei， ZHAO Hong-xu

2017, 38 (12): 1754-1759. DOI: 10.12068/j.issn.1005-3026.2017.12.018

Abstract ( 697 )

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The parametrically excited dynamic equation under nonlinear dynamic rolling force is constructed， which considers the dynamic rolling force and the nonlinear parametrically excited stiffness caused by chatter mark of roll surface. Then the 1/2 subharmonic resonance amplitude-frequency equation of the system is calculated by the method of multiple scales， and the subharmonic resonance characteristics with the change of damping and parametrically excited stiffness are obtained， then the bifurcation characteristics of the system in the situation of non-autonomy is obtained by the use of singularity theory. Finally， by taking the actual parameters of the rolling mill， the amplitude-frequency characteristics， bifurcation and chaos characteristics in different parameters are analyzed， it is found that many different movement patterns such as periodic motion and chaos arises with the change of nonlinear parametrically excited stiffness， which provides a theoretical reference for the further suppression of the rolling mill vibration.

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Microstructure and Performance of AISI304 /Mild Steel Vacuum Diffusion Bonded Joint

HUANG Xu-qiang， WANG Da-wei， XIU Shi-chao

2017, 38 (12): 1759-1763. DOI: 10.12068/j.issn.1005-3026.2017.12.019

Abstract ( 967 )

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The vacuum diffusion bonding technology is used to connect the AISI304 austenitic stainless steel and low carbon steel dissimilar materials. Under the condition of constant temperature and pressure， the influence of the bonding time on the microstructure and properties of the AISI 304 austenitic stainless steel and low carbon steel bonded joint was studied. The results show that a good diffusion bonding between the mentioned two materials can be acquired with 850℃ bonding temperature， 10MPa bonding pressure， and 60min bonding time. Also with these parameters， the strength and toughness are higher than the low carbon steel base material level， that the tensile strength reaches 440MPa at the bonding joint， and the tensile fracture occurs at the low carbon steel side. In high temperature environment， carbide segregation phase (Cr₂₃C₆) appears at the interface， decreasing the interfacial toughness. Longer bonding time can effectively prevent the precipitation of harmful compounds Cr₂₃C₆， and enhance the impact toughness up to 120.5J/cm². With this condition， the impact fracture occurs in low carbon steel side.

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RGB-D Based Indoor Scene Real-Time 3D Reconstruction Algorithm

HU Zheng-yi， TAN Qing-chang， SUN Qiu-cheng

2017, 38 (12): 1764-1768. DOI: 10.12068/j.issn.1005-3026.2017.12.020

Abstract ( 1221 )

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A novel RGB-D based feature point depth constraint and locality constraint integrated real-time indoor scene 3D reconstruction algorithm is proposed， which focusing to solve problems such as the inaccuracy of 3D point cloud matching， excessive time consuming and the loss of point depth. Firstly， the feature points are detected using Harris point detector， and then labeled with 64 dimensional vector using SURF descriptor. Secondly， the initial correct feature point pairs are selected between the successive frames with the depth information constraint and feature point locality constraint in addition to vector similarity constraint. Thirdly， the outliers are removed and the camera pose is estimated based on the random sample consensus(RANSAC) method. Eventually， 3D point clouds are determined using the general graph optimization (g2o) facilitating the indoor scene reconstruction. In the experiments， the RGB-D camera is fixed on the automatic guided vehicle to capture the indoor surrounding scenes. Experimental results validate that the proposed approach is feasible and effective.

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Mineralogical Study of Vanadium Titanium Magnetite Ore in Chaoyang

TANG Zhi-dong， LI Wen-bo， GAO Peng， HAN Yue-xin

2017, 38 (12): 1769-1774. DOI: 10.12068/j.issn.1005-3026.2017.12.021

Abstract ( 961 )

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The chemical composition， occurrence state of elements， mineral composition， dissemination relationship and size distribution of the vanadium titanium magnetite ore in Chaoyang were analyzed through traditional process mineralogy method and optical microscope， XRD， chemical analysis， etc. The results show that mineral composition of this ore is very complex. Primary recoverable minerals are magnetite， titanomagnetite and coulsonite， and feldspar is the main gangue mineral. The dissemination relationship among main minerals is complex， magnetite is closely linked to titanomagnetite with great difficulty to be separated. Dissemination particle size of magnetite is coarse， while that of titanomagnetite and coulsonite is fine. The results may provide the basis for the rational exploitation of the vanadium titanium magnetite resource.

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Flotation Behavior of Quartz and Hematite in the Presence of Alkyl Hydroxypropyl Amine

LIU Wen-bao， LIU Wen-gang， WANG Xin-yang， ZHANG Yao

2017, 38 (12): 1775-1779. DOI: 10.12068/j.issn.1005-3026.2017.12.022

Abstract ( 687 )

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Flotation behaviors of quartz and hematite in the presence of a new collector alkyl hydroxypropyl amine (NDIA) were investigated through flotation experiments. Combined with quantum chemical calculation and zeta potential analysis， the adsorption mechanism of NDIA on the mineral surface was studied. Flotation results of pure mineral showed that the flotation recovery of quartz was above 92% and the flotation recovery of hematite was around 50%， when the dosage of NDIA was 33.33mg/L， and pH value of the pulp was set from 4.50 to 8.00. Flotation results of artificial mixed mineral showed that quartz and hematite were effectively separated， when the dosage of NDIA was 33.33mg/L， the dosage of starch was 13.33mg/L and pH value of the pulp was set from 4.50 to 8.00. The results of quantum chemistry calculation indicated that NDIA had a better flotation performance than DDA to quartz. According to the results of zeta potential test，NDIA was adsorbed on both quartz and hematite surface， but the adsorption ability of NDIA on quartz surface was much stronger than that on hematite.

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Three-Dimensional Numerical Analysis of Coastal Soft Soil Foundation Consolidation by Surcharge Preloading

ZHANG Guo-lian， ZOU Hai-wen， WANG Yu-qi， ZHAO Xian-tao

2017, 38 (12): 1780-1784. DOI: 10.12068/j.issn.1005-3026.2017.12.023

Abstract ( 679 )

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Plastic drainage plate has been used widely to treat soft soil foundation. Now， the popular analysis method for plastic drainage plate foundation is plane strain finite element method. However， the pore water pressure and horizontal displacement results are unsatisfactory. In this paper， a large scale 3D finite element model is established to simulate the soft soil foundation using ABAQUS， combined with an engineering example of reinforcing soft-soil foundation by preloading with plastic drainage plate. The calculated settlement curve and pore pressure curve of soft soil foundation agree with the field measurements， confirming the reliability of 3D PVD element. By changing the time of filling and the time of preloading， observing the variation of excess pore water pressure and surface subsidence， the best construction scheme is determined. The research results can provide guidance and reference for the design and construction of the soft soil foundation preloading in the future.

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Frost Heaving Model Test and Response Analysis of Pile-Anchor Foundation Pit in Cohesive Soil Area

DAI Wu-kui， LIANG Li， XIN Quan-ming

2017, 38 (12): 1785-1789. DOI: 10.12068/j.issn.1005-3026.2017.12.024

Abstract ( 596 )

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Frost heaving effect of foundation pit in cohesive soil has a significant impact on engineering construction and support design. Based on selected foundation pit in Northeast China， mechanical deformation law of pile-anchor foundation pit in cohesive soil and the relationship between frozen earth pressure and displacement are derived through a series of laboratory experiments. Deformation-compatibility equations of supporting structure are introduced using the finite difference method considering soil-pile interaction， so that supporting system of the frost heaving pile-anchor foundation pit can be quantitatively designed. The case of the frost heaving effect on foundation pit offers a new method for anchor-pile system under the consideration of frost heaving action imposed by foundation pit with the influence of frost heaving pressure， which is more accurate to the actual condition of engineering monitoring， and can be applied to similar projects.

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Dam-Break Risk Assessment Model of Tailings Reservoir Based on Variable Weight Synthesis and Analytic Hierarchy Process

LIANG Li， LIU Qi， LI Ming

2017, 38 (12): 1790-1794. DOI: 10.12068/j.issn.1005-3026.2017.12.025

Abstract ( 675 )

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There are many interacting and coupling factors that affect the stability of tailings reservoir， so the dam-break risk assessment of tailings reservoir is uncertain. The hierarchical structure model is established according to the factors affecting the safety of tailings reservoir， analytic hierarchy process (AHP) judgment matrix is constructed， and the weights of each factors is obtained using AHP to combine qualitative analysis with quantitative analysis. The variable weight synthesis theory is introduced to AHP. Constructing the balance function and using the balance coefficient α to optimize the weight of each influence factor. The application of the engineering example results shows that this method can get more reasonable evaluation results. At the same time， the impact of single factor change on the evaluation results is analyzed， and the differences between the variable weight evaluation and the constant weight evaluation are comprehensively analyzed. The results show that the variable weight evaluation can better reflect the actual situation of the project， especially when the index parameters are poor， the variable weight evaluation can significantly reduce the score.

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Hydrogen Explosion Accident Analysis of Aluminum Alloy Grinding Wet Dust Removal System Based on WBS-RBS-BN

WANG Yan-tong， XU Kai-li

2017, 38 (12): 1795-1799. DOI: 10.12068/j.issn.1005-3026.2017.12.026

Abstract ( 708 )

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Aluminum grinding process using wet dust removal system can avoid dust explosion，but there is a risk of hydrogen explosion accident. The research on the risk assessment of aluminum wet dust removal system and safety management is limited. A WBS-RBS-BN evaluation method for hydrogen explosion accident is presented. The coupling matrix and hydrogen explosion fault tree could be identified by decomposing WBS-RBS the risk factors of wet dust removal system. The fault tree could be changed into Bayesian networks， and the explosion probability is 5.54E-07. After calculating the posterior probability of basic events， basic events leading to the accident are clarified and identified. The study is helpful for the guidance of safety management.

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The Low-Carbon Economy Evaluation Model and Its Empirical Research Based on the Gini Revised G1 Combination Weighting

WANG Bin， LI Gang， LIU Li-bo， CHEN Kai

2017, 38 (12): 1800-1804. DOI: 10.12068/j.issn.1005-3026.2017.12.027

Abstract ( 574 )

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The purpose of this paper is to realize the evaluation of the level of low-carbon economy by the low-carbon economy evaluation model， and find the effecting factors which influence the development of low-carbon economy. The evaluation results of low-carbon economy can provide theoretical guidance for the low-carbon economic development. The paper first developed the low-carbon economy evaluation index system， and then determined the weights of indicators by Gini and G1， establishing the comprehensive evaluation model of low-carbon economy based on Gini revised G1. At last， the paper did empirical analysis on the level of low-carbon economy development of Qinhuangdao between 2005~2015， determining its status and influence factors. In the meantime， the paper provides theoretical references for the development of low-carbon economy in Qinhuangdao.

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