Journal of Northeastern University(Natural Science)

Study on Relay Structure for Wireless Power Transmission System via Electromagnetic Resonant Coupling

WANG Hao， WANG An-na， ZHAO Qiang， HUI Guo-tao

2016, 37 (7): 913-917. DOI: 10.12068/j.issn.1005-3026.2016.07.001

Abstract ( 800 )

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In order to analyze the transmission efficiency of wireless power transmission system via electromagnetic resonant coupling with relay structure， the relay system model was set up and analyzed with couple mode theory. In addition， the same power change rule compare with non-relay system was derived out. Take advantage of electromagnetic simulation software to make a system analyze with the magnetic field distribution of the power transmission system， and to analyze the circuit model of relay system to get the load power ratio， the motion as relay coefficient was proposed. In this way， the relationship between the load voltage ratio and relay coefficient was derived out. According to equivalent relation of load voltage， the model of relay coefficient was obtained， which could calculate reasonable relay coefficient. Finally， the accuracy of this model was verified by the experimental results.

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Current Peak Control of Brushless DC Motor Based on DSP

BIAN Chun-yuan， XUE Sheng-xian， LI Shi-yin， KANG Miao-miao

2016, 37 (7): 918-921. DOI: 10.12068/j.issn.1005-3026.2016.07.002

Abstract ( 730 )

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To realize the square-wave current of high-power brushless DC motor (BLDCM)， a current peak control strategy using PWM_ON_PWM modulation mode was proposed and the control principle was described in detail. Then the concrete implementation plan was given. Through the direct control of the non-commutation phase current， the response speed of the system was improved and the desired square-wave current waveform was almost achieved， then the torque ripple of the motor was reduced finally. The simulation model of BLDCM was set up by PLECS to achieve the current peak control strategy. The experiment platform for current peak control of BLDCM was set up by DSP control chip. The simulation and experiment results showed that this control strategy can not only achieve the square-wave control， but also control the switching frequency of the power switching devices.

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Enhancement Algorithms of Retinal Blood Vessels Based on Curvelet Conversion

ZHANG Shi， SHE Li-huang， GE Xin

2016, 37 (7): 922-926. DOI: 10.12068/j.issn.1005-3026.2016.07.003

Abstract ( 704 )

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In retinal vascular images， characteristic of image， such as low contrast， will interfere with the normal image segmentation. In allusion to the image characteristics of retinal blood vessels ， an enhancement algorithms of retinal blood vessels was proposed based on improved curvelet conversion. Firstly， a preprocessing was performed with the green channel of retinal image， combined with the adaptive enhancement of transform coefficient to achieve the process. The improved morphological transformation was also used to suppress background and enhance the vessel image information with more brightness. With the comparison to other methods， the experiment result showed the validity and the values of the method in improving contrast and reducing noise.

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Multi-skilled Workforce Scheduling Model for MRO Service Center

CHEN Di， SUN Fu-quan， LIU Shi-xin

2016, 37 (7): 927-930. DOI: 10.12068/j.issn.1005-3026.2016.07.004

Abstract ( 642 )

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The resources scheduled affect the profit of MRO (maintenance，refair and overhaul) service companies directly. From the perspectives of MRO service provider， an optimization scheduling problem of multi-skilled workforce working was studied for customers distributed in different locations. Considering workforce travel cost and time cost， a multi-skilled workforce scheduling optimization model was established to get the minimum total workforce cost， which is an integer nonlinear programming model. According to the characteristics of integer variables， the model was linearized， and solved by means of ILOG CPLEX. Through a large number of simulation experiments with different parameters， the validity of the model was verified.

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Mining Full Weighted Maximal Frequent Itemsets Based on Sliding Window over Data Stream

WANG Shao-peng， WEN Ying-you， ZHAO Hong

2016, 37 (7): 931-936. DOI: 10.12068/j.issn.1005-3026.2016.07.005

Abstract ( 665 )

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Aiming at the problem that none of current researches on the WMFI (weighted maximal frequent itemsets) over data stream emphasizes the WMFI mining on the condition that the frequent threshold is not equal with the weighted frequent threshold， the concept of FWMFI (full weighted maximal frequent itemsets) was firstly promoted in this work. In order to reduce redundant operations existing in the naive algorithm which is used to handle the FWMFI mining based on sliding window over data stream， the FWMFI-SW (FWMFI mining based on sliding window over data stream) algorithm was proposed. The mining optimization strategy was adopted based on the frequent character to reduce the unnecessary call about the MaxW optimization strategy in the naive algorithm. In addition， the edit distance ratio was taken as reconstruction judge function to decide whether the updated WMFP-SW-tree should be reconstructed as the window slides. The extensive experiments showed that the FWMFI-SW algorithm is effective ， and outperforms the naive algorithm in running time.

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Keyword Querying of Fuzzy XML

LI Ting， MA Zong-min

2016, 37 (7): 937-941. DOI: 10.12068/j.issn.1005-3026.2016.07.006

Abstract ( 589 )

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In the practical application，there often exists uncertainty and ambiguity in the data. Keyword query processing over fuzzy XML data becomes a requirement for non professional users. Aiming at making a research on the method of keyword querying over fuzzy XML data，the semantics of keyword querying over fuzzy XML was analyzed， and a new coding method CDewey for the fuzzy XML document was proposed. Types of nodes could be effectively distinguished by this coding method. On the bases， a keyword query algorithm FIndex Loop was proposed， this algorithm can get the SLCA results of keywords inputted and values of possibilities of the results accurately. Finally， experimental results showed the effectiveness of the query method.

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Hierarchical Granular Support Vector Regression Based on Distance and Temporal

WANG Jue， QIAO Jian-zhong， LIN Shu-kuan

2016, 37 (7): 942-946. DOI: 10.12068/j.issn.1005-3026.2016.07.007

Abstract ( 569 )

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Only distance factor is considered in the granular algorithm of granular support vector regression. Temporal factor was introduced simultaneously in granular algorithm. Hierarchical granular support vector regression based on distance and temporal factors(DTHGSVR) was proposed which is applicable for financial time series. The training samples were mapped into the high-dimensional space by mercer kernel， and the samples were divided into some granules initially. Then， the granules which have more regression information was found by measuring the distances between the granules and regression hyperplane and the granule’s temporal factor. By computing the radius， density of granules and the temporal factor， the deeper hierarchical granulation process was executed until no granules was needed to be granulated. Finally， those granules in different granulation levels were trained by SVR. Fund net was forecast by the hierarchical granular support vector regression based on distance and temporal factors. Experimental results showed the generalization performance of regression had been improved.

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Effect of Temperature on Microstructure and Mechanical Properties of X12CrMoWVNbN10-1-1 Steel

LIU Yue， GUO Hao， MA Yu-lin， GU Jin-tao

2016, 37 (7): 946-950. DOI: 10.12068/j.issn.1005-3026.2016.07.008

Abstract ( 767 )

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The high temperature mechanical tests of X12CrMoWVNbN10-1-1 heat-resistant steel were carried out with the different testing temperature in the range of 300~600℃. The microstructure and fracture morphology of the samples at different temperature tests were analyzed using OM， SEM and TEM. Effect of temperature on the microstructure and high temperature mechanical properties was studied. The results showed that when the testing temperature increased in the range of 300~400℃， the quantity and size of brittle M₃C carbides gradually increased and the segregation became more significant， resulting in an increase of precipitation strengthening and work hardening. For plastic deformation stage， the stress concentration and cracks were more prone to appear around M₃C carbides during deformation. The plasticity slowly decreased with temperature. When the temperature increased between 400℃ and 600℃， it was found that the carbides started to transform， M₃C carbides decomposed rapidly， M₇C₃ and M₂₃C₆ carbides gradually precipitated and the quantity of precipitations began to decrease， which resulted in a decrease of strengthening ability. Meanwhile，dynamic recovery became more significant and led to a dramatic decrease of strength and rapid increase of plasticity.

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Effect of Deformation Temperature on Stability of Austenite in Fe-11Mn-4Al-0.2C Steel

CAI Zhi-hui，DING Hua，YING Zheng-yan

2016, 37 (7): 951-955. DOI: 10.12068/j.issn.1005-3026.2016.07.009

Abstract ( 648 )

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The cold-rolled 11 wt% Mn steel was investigated in this work. The microstructure and mechanical properties of the samples tensioned at different temperatures were studied to investigate the effect of deformation temperature on the stability of austenite in the steel. The temperature of M^σ_s was finally determined in the range of 20~25℃. The results showed that the stability of austenite increased with increase of the temperature during straining，leading to decrease of the strain hardening ability. When the samples were tensioned at the temperature around M^σ_s， both of the stress-induced and strain-induced martensitic transformation were found. Therefore， the best combination of strength and ductility was obtained， which mainly contributed by TRIP effect. The average grain size in the austenite was calculated in the range of 0.70~0.71μm by a theoretical model.

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Study on CO₂ Sorption-Enhanced Steam Reforming of Bio-oil Model for Hydrogen Production

YU Qing-bo， YAO Xin， WU Tian-wei， XIE Hua-qing

2016, 37 (7): 956-959. DOI: 10.12068/j.issn.1005-3026.2016.07.010

Abstract ( 679 )

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With Ce-Ni/Co as reforming catalyst and CaO from calcination of calcium acetate as CO₂ adsorbent， the sorption-enhanced steam reforming of bio-oil for hydrogen production was studied. The results show that the addition of CO₂ sorbent can effectively promote the hydrogen molar fraction and hydrogen yield compared with the case without CO₂ sorbent under the same temperature and M(S)/ M (C) ratio (the molar mass of steam to carbon in the model compounds of bio-oil ). When the CO₂ sorbent existed， the hydrogen molar fraction and yield increased first，then decreased with the increase of the reforming temperature， and reached the maximum at 700℃. With the increase of M(S)/M(C) ratio， the hydrogen molar fraction increased first，then decreased， and was the largest at the M(S)/M(C) ratio of 9，while the hydrogen yield increased till the M(S)/M(C) ratio reached 9， then changed slightly. With the increase of M(CaO)/M(C) ratio ( the molar mass of calcium oxide to carbon in the model compounds of bio-oil)， the hydrogen molar fraction increased gradually， but changed slightly after the M(CaO)/M(C) ratio reached 3， while the hydrogen yield increased first and then decreased， reached the maximum at the M(CaO)/M(C) ratio of 3. The optimum conditions for steam reforming of bio-oil with CO₂ sorption are 700℃， M(S)/M(C)=9 and M(CaO)/M(C)=3， where the hydrogen molar fraction and the hydrogen yield are 92.2% and 84.1% respectively.

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Experimental Study on Pelletizing Process of Prepared Pellets for Silicothermic Magnesium Production

WEN Ming， ZHANG Ting-an， DOU Zhi-he

2016, 37 (7): 960-963. DOI: 10.12068/j.issn.1005-3026.2016.07.011

Abstract ( 739 )

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The magnesium preparation process of silicothermic reduction exists the problems of high energy consumption and high cost. Focusing on these disadvantages， a new technology of pellet preparation→calcination→reduction was proposed. In order to control the growth of prepared pellets for silicothermic reduction process， the pelletizing growth characteristics of dolomite pellet and the influence factors on the forming process of pellets are studied. The results indicate that the growth of the pellets mainly follows the coalescence mechanism in the discontinuous pelletizing process. The growth of the pellets mainly follows the stratification mechanism in the continuous pelletizing process. The growth rate of the prepared dolomite pellets increases with the increase of the moisture content in raw materials. With the increasing of kaolin addition， the growth rate of pellet increases. In addition， grinding method has an effect on the growth behavior of pellets. With the increase of moisture content， the growth rate of pellets also increases accordingly.

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Electrolytic Preparation of Al-Mg-La Master Alloys from MgCl₂-KCl- AlF₃-(La₂O₃) Molten Salt

JANG Pok-nam， WANG Zhao-wen

2016, 37 (7): 964-968. DOI: 10.12068/j.issn.1005-3026.2016.07.012

Abstract ( 740 )

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0.6 wt% of La₂O₃ was dissolved in MgCl₂-KCl-AlF₃ molten salt system (with mass ratio of 41.5∶48.5∶10). Al-Mg-La master alloy was prepared by electrolysis process. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) and X-ray diffraction (XRD) analysis were used to determine the composition and phases of the alloy. The results show that，the current efficiency can reach 86.2%， and the main alloy phases are α-Mg， β- Al₁₂Mg₁₇ and Al₁₁La₃under the electrolysis conditions of 800℃ of electrolytic temperature， 6.92A/cm² of cathode current density， 5.3~5.4V of the cell voltage， and 1 hour of electrolysis time. High cathode current density is helpful to increase the magnesium content in the alloy.

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Fatigue Life Degenerating Rule of Pre-corroded Aviation Aluminum Alloy

ZHOU Song， XIE Li-yang， HUI Li， WANG Lei

2016, 37 (7): 969-974. DOI: 10.12068/j.issn.1005-3026.2016.07.013

Abstract ( 779 )

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Fatigue fracture usually happens in service process because of the corrosion damage for aerospace aluminum alloy. The effect of pre-corrosion damage on the fatigue life of 2xxx aluminum alloy without clad layers under different stress ratio was studied using stereo microscope， SEM and fatigue tests. The affecting mechanism of pre-corrosion damage on the initiation and propagation of fatigue crack was also discussed. The results show that pre-corrosion damage has a significant effect on the fatigue performance， i.e. fatigue strength decreases with the increase of pre-corrosion extent. A C-T-R effect model of pre-corrosion defect on the fatigue limit was proposed. The fatigue limit effect factor C increases with the increase of pre-corrosion time or stress ratio R. Fracture analysis shows that the pre-corroded damage would result in the emergence of crack changing from single source to multiple sources and the crack initiation life would decrease because of the pre-corroded damage.

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Remaining Useful Life Interval Estimation for Machine Parts Based on SVM

WANG Jian， SUN Zhi-li， YU Zhen-liang， CHAI Xiao-dong

2016, 37 (7): 974-978. DOI: 10.12068/j.issn.1005-3026.2016.07.014

Abstract ( 708 )

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To improve the accuracy of remaining useful life estimation for machine parts， an interval estimation model was proposed based on the SVM (support vector machine). The linear theory and nonlinearity theory of SVM were briefly introduced， and the correlation between input variable and output variable was analyzed. Degraded index and remaining useful life of machine parts were treated as input variable and output variable， correspondingly. It was assumed that input variable and residual error were independent and the residual error’s distribution pattern was known. Distribution parameters of residual error were estimated by means of the MLE (maximum likelihood estimation). Then the confidence interval of SVM output variable was obtained under a certain confidence level. The MSE (mean squared error) was used to measure the prediction of SVM. The SVM parameters were gotten by the means of variable step size grid search. A numerical example was presented to show that the proposed model can estimate the remaining useful life confidence interval precisely with the engineering application values and generality.

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Experimental Research and Parameter Optimization for Low Speed Wire Electrical Discharge Machining TC4

SUN Yao， GONG Ya-dong， LIU Yin

2016, 37 (7): 979-983. DOI: 10.12068/j.issn.1005-3026.2016.07.015

Abstract ( 675 )

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LS-WEDM (low speed wire electrical discharge machining) TC4 was regarded as the research object， the influence of peak current， open circuit voltage， pulse width， wire speed and wire tension’s effects on process time， kerf width and surface roughness was studied by SNR (signal to noise ratio) method. The gray correlation analysis was applied to realize the transformation from multi-objective parameter optimization to signal objective optimization of grey correlation degree and the optimum machining parameter combination of LS-WEDM were obtained under the multiple technical index requirements. Multi-objective parameter optimization results show that when the peak current is 30A， the open circuit voltage is 100V， the pulse width is 20μs， the wire speed is 105mm/s and wire tension is 12N， the surface roughness， kerf width and process time were reduced by 8.35%， 2.59% and 26.06%， respectively.

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Analysis on Inverse Problem of Lunar Roving Vehicle Moving Trajectory with Continuous Curvature

LIANG Zhong-chao， WANG Yong-fu， GAO Hai-bo

2016, 37 (7): 984-989. DOI: 10.12068/j.issn.1005-3026.2016.07.016

Abstract ( 649 )

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For analyzing the handling deviations of the lunar roving vehicle (LRV) when the astronauts driving it under the earth and lunar gravities， the inverse dynamical system of the LRV was established using the linear quadratic optimal theory， and the trajectory functions with the continuous curvature were deduced under the traditional condition. Then， when the astronauts drove the LRV in the same path under the different gravities， the handling inputs could be solved using the inverse system and trajectory functions. The calculation results show that， for moving in the same path under the different gravities， the astronauts when driving an LRV on the lunar surface need much faster handling speed， bigger handling amplitude， and more frequently handling conversion than driving on the earth. Therefore， it illustrates that the LRV on the moon is much more difficult to handle.

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Ratcheting Effect of Pressurized Straight Pipe Under Displacement Control

CHEN Xiao-hui， CHEN Xu

2016, 37 (7): 990-993. DOI: 10.12068/j.issn.1005-3026.2016.07.017

Abstract ( 522 )

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The ratcheting effect of pressurized straight pipe was studied for nuclear power plant. The effect of internal pressure， displacement and multistep loading on ratcheting strain was mainly studied. The results indicated that ratcheting strain occurs mainly in hoop direction and it′s not evident in axial direction. Ratcheting strain increases with the increasing of displacement at the same pressure. At the same displacement， ratcheting strain increases with the increasing of internal pressure. For multi-step loading， ratcheting strain rate in the next step would be decreased by ratcheting deformation in the preceding step. The effect of ratcheting history at higher level loading on ratcheting strain is larger than that at lower level loading. According to the quasi-three-point-bending apparatus， ratcheting boundary was determined.

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Variable Structure Control with Sliding Mode for ABS of Vehicle Based on EMB System

ZHOU Shu-wen， CHEN Qing-ming， SUN Da-ming

2016, 37 (7): 994-997. DOI: 10.12068/j.issn.1005-3026.2016.07.018

Abstract ( 679 )

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Compared with the traditional hydraulic brake system or the pneumatic braking system， the electromechanical brake is being paid increasing attention due to its simple structure， short response time and high braking efficiency. Therefore， based on the as-designed electromechanical brake device， a variable structure controller with sliding mode for anti-lock braking system (ABS) was proposed. A vehicle model which was built in the Carsim and control system was designed in Simulink. Then， a co-simulation was conducted between the Carsim and the Simulink. By comparing with the braking performance of the traditional hydraulic brake， using the logic threshold method with the electromechanical brake， it was verified that variable structure control with sliding mode method for anti-lock braking system is effective in vehicle equipping with the electromechanical brake system and advanced in braking performance.

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Labor Hour Estimation Based on the Difficulty Coefficient of Parts Processed

YANG Xu-chang， CHEN You-ling

2016, 37 (7): 998-1002. DOI: 10.12068/j.issn.1005-3026.2016.07.019

Abstract ( 981 )

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According to random order and many kinds of product， it is difficult to get labor hour in the current production environment， the relationship between the difficulty coefficient of parts processed and labor hour was researched. To quickly and accurately determine the labor hour， a method based on the difficulty coefficient of parts processed was presented. Considering the key factors affecting parts processing time， an evaluation index system for the process difficulty was built. In the model， the entropy value method and group decision theory were introduced to analyze the influencing factors of difficulty coefficient comprehensively. Based on historical data of time-quota， the correlative function of the process difficulty coefficient and time-quota was built using the MATLAB. The method was verified to be accuracy and efficiency by experiment.

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Classification of Causality in Bond Graph Model for Linear Actuator Revolute Joint Mechanism

LI Xiao-tian， WANG An-lin

2016, 37 (7): 1003-1007. DOI: 10.12068/j.issn.1005-3026.2016.07.020

Abstract ( 574 )

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Bond graph modeling for linear actuator revolute joint mechanism which uses Lagrange approach or stiff compliance approach with new elements inserted causes stiff equation problems， and causality in bond graph is not classified and modularized. A causality classification method is proposed for modeling with this kind of mechanism. Classifications for elements are classified as main-body， cylinder and lever type by analysis of element bond graphs and connection patterns， and joints are classified as root， pusher， pushed and load type to maintain the original causal link. Causality determination principles are proposed by these definitions to make modeling orderliness. An excavator mechanism modeling and simulation demonstration proved that proposed method is suitable for mechanism cases of earthmoving vehicles.

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Torsional Vibration Characteristics of PMSM for HEV Considering the Electromagnetic Excitation

CHEN Xing， YUAN Shi-hua， CHEN Kai， REN Yong

2016, 37 (7): 1008-1013. DOI: 10.12068/j.issn.1005-3026.2016.07.021

Abstract ( 735 )

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An nonlinear torsional vibration characteristics of permanent magnet synchronous motor’s rotor system under the electromagnetic and mechanical excitations were investigated. The model of electromechanical excitation was derived by an energy method. The method of multiple scales was used to solve the equation of motion. The steady state solutions and stability were determined. The effects of inner power factor angle， pole pairs， saturation coefficient and torsional stiffness of shaft on rotor system torsional vibration were studied. The results indicate that it could avoid the amplitude jump and bifurcation instability phenomenon through the reasonable control of permanent magnet synchronous motors and design of electromagnetic and mechanical parameters.

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Influence and Mechanism of Metal Ions on Flotation of Molybdenite

YUAN Zhi-tao， ZHANG Qi-dong， LIU Jiong-tian

2016, 37 (7): 1013-1016. DOI: 10.12068/j.issn.1005-3026.2016.07.022

Abstract ( 776 )

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The influences and mechanism of metal ions on the flotation of molybdenite were investigated by flotation experiments and measurements of zeta potential with single molybdenite. The results show that Ca²⁺， Cu²⁺， Pb²⁺and Fe³⁺can adsorb on the surface of molybdenite. Ions like Cu²⁺， Pb²⁺and Fe³⁺ can depress flotation of molybdenite while Ca²⁺ shows no significant influence. Solution chemistry calculations confirm that the hydrophobic surfaces of molybdenite become hydrophilic and molybdenite flotation is depressed within certain pH range due to hetero-coagulation of the metal hydroxides of Cu²⁺， Pb²⁺and Fe³⁺on both the polar and nonpolar surfaces of molybdenite.

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Node State Trend Analysis Model and Its Application of Petrochemical Device BN Topological Structure

TANG Gui-cheng， XU Kai-li， LI De-shun， LIU Jia-xi

2016, 37 (7): 1017-1021. DOI: 10.12068/j.issn.1005-3026.2016.07.023

Abstract ( 590 )

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For the changing risk of the petrochemical device， the node state trend expression form of the petrochemical device BN(Bayesian network) topological structure is given based on general set pair analysis(GSPA) theory and BN， the node state trend calculation model of the petrochemical device BN topological structure is proposed， the node state trend grade of the petrochemical device BN topological structure is discussed， and the node state trend grade is divided in the same situation. Application results show that the leaf node “the reaction fire explosion” belongs to the same situation， and the reactor fire explosion event occurrence is major in the BN topological structure of the reactor fire explosion. The intermediate node connection degree and its state trend level are obtained， and the difference change of the connection degree will have some certain impact on the corresponding node situation and the node level， even the situation is reversed， and provides the basis for the node state and its state situation analysis of BN topological structure.

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Numerical Investigation of Ultimate Bearing Capacity for Transversely Isotropic Geostructures

CHANG Jiang-fang， CHU Xi-hua， XU Yuan-jie

2016, 37 (7): 1022-1027. DOI: 10.12068/j.issn.1005-3026.2016.07.024

Abstract ( 621 )

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An elastic-plastic model for transversely isotropic geostructures is developed based on the Cosserat continuum. In the model， the elastic constitutive relationship is described by 5 deformation parameters and the Drucker-Prager yield criterion is extended by introducing fabric tensor and loading direction in the plastic stage. The iterative format for return mapping algorithms and the tangent modulus matrix are formulated for the proposed model. The numerical simulation is implemented based on the user subroutine (UEL) of ABAQUS， and a plane strain 8-noded reduced integrated element is used. The influence of the material principal direction and the anisotropic degree on the strain localization and the bearing capacity of the structure are analyzed. Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of transversely isotropic geostructures. Furthermore， the mesh dependency accompanied with strain localization is effectively solved.

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Mechanism of Hydrofracture Propagation Control by Non-uniform Pore Pressure Field

LU Yi-yu， JIA Yun-zhong， TANG Ji-ren， SONG Chen-peng

2016, 37 (7): 1028-1033. DOI: 10.12068/j.issn.1005-3026.2016.07.025

Abstract ( 724 )

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To reveal the effect of non-uniform pressure on hydraulic fractures propagation， the porous elasticity mechanics， fracture mechanics， seepage mechanics and thermal elasticity mechanics were used to build a hydrofracture crack tip stress intensity factor calculation model considering the pore pressure. Then， through laboratory experiments and numerical simulation， the guiding mechanism of pore pressure on hydrofracture was verified. The research results showed that pore pressure can increase the crack tip stress intensity factor of hydrofracture， which causes the fractures extend to the high pore pressure region; at the same time， stress intensity factor of hydrofracture will be enlarged with the increase of pore pressure. A larger pore pressure will lead to larger deflection amplitude of fractures.

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Three Dimensional Statistical Analysis of Fracture Roughness of Sandstone Under Shear Loading

XU Jiang， LIU Yi-xin， TAN Hu， ZHANG Hai-long

2016, 37 (7): 1034-1039. DOI: 10.12068/j.issn.1005-3026.2016.07.026

Abstract ( 649 )

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The characteristics of fracture roughness of sandstone under shear loading were specifically discussed through the fracture surface scanning visual map， contour map of the distribution of the fracture surface and the fracture surface profile contour， according to the 3D information of fracture roughness of sandstone under shear loading collected by self-developed coal or rock shear-flow coupling test device and 3D scanners. It is showed that the deformation characteristic curves generally were in good agreement， the visual features of fracture surface were different from each other， and the distribution of roughness heights was appromiately accorded with normal distribution. Characteristics of profile along the shear direction and perpendicular to the shear direction are different， and cannot reflect the whole fracture surface features. The analysis of roughness parameters relationship among R_○L， R_○S and JRC suggests that there was a linear correlation between JRC and R_○L， and the linearity of R_○S and the average value of JRC was better than that of JRC and R_○L. So the average value of JRC is more suitable to reflect the 3D characteristics of fracture surface.

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Study on the Sectional Area and Height of Vertical Sand Silo and Its Application

CHEN Qiu-song， ZHANG Qin-li， WANG Xin-min， XIAO Chong-chun

2016, 37 (7): 1040-1044. DOI: 10.12068/j.issn.1005-3026.2016.07.027

Abstract ( 906 )

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Based on indoor experiments， aggregate balance theory and fluid dynamics theory， mathematical models of vertical sand silo area and height were established. The core of sectional area calculation model is the effective sedimentation velocity which is equal to the ratio of the descent height of the liquid level and the sedimentation time. The height calculation model consists of compression layer， sedimentation layer， overflow layer， reserving sand space and stable sand height. Because the calculation of the compression layer height is the key part in the model， an equation on compression layer height and mortar concentration was put forward. Then this method was applied to a vertical sand silo. It was got that the diameter of the vertical sand silo is 10m， and the height of vertical sand silo is 26.5m. The field operation trial showed that the bottom flow volume fraction of sand silo can reach 44% (the mass fraction is 69%) and the volume fraction of over-flow water can be controlled under 3%， which means the concentration effect is very well.

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Time-Varying Characteristic of Paste-like Super-Fine Unclassified Tailings in Long Self-Flowing Transportation

LI Shuai， WANG Xin-min， ZHANG Qin-li， WANG Shi

2016, 37 (7): 1045-1050. DOI: 10.12068/j.issn.1005-3026.2016.07.028

Abstract ( 596 )

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A time-dependent rheological model was built based on the H-B rheological model and the slurry flocculent structure theory. Time-varying characteristic of paste-like super-fine unclassified tailings in long self-flowing transportation was explored， and the friction loss formula of pipes was derived. By using the 68% mass concentration paste-like slurry of a deep iron mine， groups of shear rheological tests were implemented， and the pipes friction loss was verified. It is revealed that the paste-like super-fine unclassified tailings show obvious shear thinning under different shear rate. The higher the shear rate is， the faster the balance can be reached and the lower the viscosity is. With a flow of 80m³/h， the friction loss takes 225s to reach a stable value of 5.03MPa/km， which is just 50.6% of the initial resistance. Therefore， it is quite economic and reasonable to calculate the friction loss of paste-like slurry by using the stable value in long distance pipeline transportation.

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Nonlinear Buckling of Parabolic Single-Layer Cylindrical Reticulated Shells

HE Yong-jun， ZHOU Yuan-liang

2016, 37 (7): 1050-1055. DOI: 10.12068/j.issn.1005-3026.2016.07.029

Abstract ( 597 )

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Aiming at the static stability of the parabolic single-layer cylindrical reticulated shell， the following research is conducted: the static stability of the parabolic single-layer cylindrical reticulated shell is compared with that of the single-layer cylindrical reticulated shell and the inverted catenary single-layer cylindrical reticulated shell. A large scale parameter analysis is carried out on the parabolic cylindrical reticulated shell. An optimized design for the parabolic single-layer cylindrical reticulated shell is conducted. Research shows that compared with the cylindrical reticulated shell， the ultimate load of the parabolic single-layer reticulated cylindrical shell is greatly enhanced. Rise-span ratio and length-span ratio influence the ultimate load of the shell significantly. The shell is proved to be sensitive to initial geometric imperfection. There exists an optimal oblique rod intersection angle of about 50° under which the static stability is the best. When the grid space layout is arranged according to the geometric series and the value of the ratio α is between 0.85 and 0.95， the static stability of the shell is the best.

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Zircon U-Pb Dating and Its Geological Significance of Lamprophyres from Qingchengzi Orefield，Liaodong

ZHANG Peng， ZHAO Yan， KOU Lin-lin， YANG Hong-zhi

2016, 37 (7): 1056-1060. DOI: 10.12068/j.issn.1005-3026.2016.07.030

Abstract ( 643 )

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To better understand the petrogenesis， tectonic environment， and geological significance of the lamprophyres in Qingchengzi， Liaodong. Zircon U-Pb dating and major elements were studied by LA-ICP-MS U-Pb and X-ray fluorescence spectrometers. Results show that characteristics of the lamprophyres have low silicon and high ferrum and magnesium. Zircon LA-ICP-MS U-Pb dating yields ages of (226.0±1.0)Ma～(227.7±1.3)Ma， which indicate lamprophyres are the product of late Indosinian magmatism in North China Craton(NCC). Combined with regional tectonic evolution， results indicate that the lamprophyreas originated from slab break-off during the process of Yangtze Craton and North China Craton continental deep subduction. The deep subduction of Yangtze continental crust and continent-continent collision could be the main reason for the late Mesozoic decratonization of the North China Craton.

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Analysis of Energy Rebound Effect Measurement of Liaoning Province

HAN Ying， LIU Qing， BAI Bao-xin， SHI Jian-hua

2016, 37 (7): 1061-1064. DOI: 10.12068/j.issn.1005-3026.2016.07.031

Abstract ( 527 )

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Both Solow residual method and DEA-Malmquist index method were used to build the calculation models which aim at calculating the energy rebound effect of Liaoning Province from 1986 to 2014. The results showed that the rebound effect of Liaoning Province is significant with an upward trend， which indicates that attention can’t be merely paid to improving energy efficiency and the rebound effect can’t be ignored.It was suggested that technological progress should be combined with industrial structure adjustment， energy price reform and market regulation so as to achieve energy conservation and emission reduction goals.

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