Journal of Northeastern University(Natural Science)

Nonlinear Prediction Research on Explosion Limits of Propylene Based on Kernel Partial Least Squares

LIU Shu-ting， GAO Xian-wen

2017, 38 (11): 1521-1524. DOI: 10.12068/j.issn.1005-3026.2017.11.001

Abstract ( 755 )

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Prediction on the propylene explosion limit is an effective way to ensure the acrylic acid safety in production. The propylene and mixture volume concentrations have nonlinear relationship between them. Therefore， kernel partial least squares method is used to predict the limits of propylene explosion and the simulation is carried out by the actual data. Simulation results showed that the algorithm was feasible and effective. Compared with those of partial least squares， the prediction results of the proposed method have more remarkable tracking capability. Meanwhile， the propylene explosion region which is from 2.56% to 9.25% is determined. So the problem of propylene explosion can be solved.

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Loss Calculation and Analysis of Efficient Permanent Magnet Coupler

YU Lin-xin， WANG Da-zhi， LI Shuo， ZHENG Di

2017, 38 (11): 1524-1529. DOI: 10.12068/j.issn.1005-3026.2017.11.002

Abstract ( 763 )

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In allusion to the problems of electromagnetic loss of the permanent magnet coupler(PMC)， a 1MW efficient PMC was utilized. Based on the theoretical analysis of loss and the theory of eddy current field， a three-dimensional finite element model of the eddy current field is established. The time-stepping finite element method is used to detailedly analyze and calculate the copper plate loss， permanent magnet eddy current loss and the torque of PM back iron of the 1MW PMC.The correctness and practicability of the analysis and calculation are validated by the experiment analysis and finite element simulation. Finally， the influence of the segmented permanent magnet on the eddy current loss is analyzed. It provides the theoretical basis for the efficiency analysis， heat dissipation design and loss optimization of PMC.

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Fetal Heart Beat Extraction Method from Ballistocardiogram Signal Based on Fast Independent Component Analysis Algorithm

JIANG Fang-fang， LIU Xing-hang， NING Guo-chen， GENG Ruo-xue

2017, 38 (11): 1530-1533. DOI: 10.12068/j.issn.1005-3026.2017.11.003

Abstract ( 828 )

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Routine fetal heart beat (FHB) clinical detection method is the fetal electrocardiogram (FECG) signal detection， which needs to attach multi-electrodes on the maternal body， limits the recordings during labor and causes inconvenience. Therefore， a non-invasive FHB detection method using fast independent component analysis (FastICA) algorithm was proposed. Through analyzing the principal component of maternal ballistocardiogram(MBCG)， FHB detection can be implemented without attaching electrodes to the subject， which is suitable for home unobtrusive health care. 45 groups of MBCG signals and maternal electrocardiogram (MECG) signals were collected synchronously to conduct the accuracy 91.3% .

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Detection of Wheeze Based on Hough Transform of Spectrogram

ZHANG Ke-xin， LONG Zhe ， WANG Xue-feng， ZHAO Hong

2017, 38 (11): 1534-1537. DOI: 10.12068/j.issn.1005-3026.2017.11.004

Abstract ( 770 )

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A method based on Hough transform to detect the wheezes from the STFT spectrum of the lung sounds was presented. This method first clips the ROI region of the STFT spectrum of the digital lung sound data， then uses the Canny operator for image edge detection， and finally identifies the wheezes automatically based on the analysis of Hough transform data. The data for clinical analysis includes the clinical acquisition of lung sounds and the international shared lung sound files. Hough transform detection method got the accuracy rate of 87% in the detection of 60 cases of wheezes， and 74% for the 70 cases of normal respiratory sound.

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Maximum Likelihood-Separable Paraboloidal Surrogate Function Algorithm for Dual-Energy CT Reconstruction

HOU Xiao-wen， TENG Yue-yang， LIU Yu-jia， KANG Yan

2017, 38 (11): 1538-1542. DOI: 10.12068/j.issn.1005-3026.2017.11.005

Abstract ( 726 )

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In the reconstruction algorithm， different lookup table problems need to be set up for different objects. An algorithm based on maximum likelihood-separable paraboloidal surrogate function was proposed. A log-likelihood function， as the objective function， was constructed based on the physical model and statistical model of dual-energy CT. Separable paraboloidal surrogate function was constructed according to the convex characteristic of the objective function. The experiment result shows that， for all of the energy levels， the correlation coefficient between the image reconstructed by this method and the original image is greater than 0.983， and the signal to noise ratio is greater than 12dB， both are greater than the corresponding values of the result using the look up table algorithm. The quality of image reconstructed by the proposed method was better than the look up table method.

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2M-dimensional Vector Matrix DCT Integer Transform and Parallel Implementation

SANG Ai-jun， CUI Xin-yu， WANG Ting， LI Xiao-ni

2017, 38 (11): 1543-1547. DOI: 10.12068/j.issn.1005-3026.2017.11.006

Abstract ( 652 )

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In order to improve the efficiency of multi-dimensional data processing operations and reduce the computing time， a 2M-dimensional vector matrix DCT(2M-VMDCT) integer transform parallel processing method is presented， according to the 2M-dimensional vector matrix DCT integer transform theory. Firstly， the 2M-dimensional vector integer transform core matrix is introduced; Then， 2M-dimensional vector matrix integer DCT transform is applied to the video compression coding， and compared with the energy concentration of the multi-dimensional discrete cosine floating-point transform; Finally， by introducing the idea of multi-core parallel processing， the processing speed is improved. The simulation results show that 2M-dimensional vector matrix DCT integer transform has a better energy concentration and the parallel implementation improves its operation efficiency significantly.

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Experimental Study on Thickness Cooling Rate of Jet Impingement Quenching for Ultra Heavy Plate

FU Tian-liang， HAN Jun， DENG Xiang-tao， WANG Zhao-dong

2017, 38 (11): 1548-1553. DOI: 10.12068/j.issn.1005-3026.2017.11.007

Abstract ( 701 )

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The effects of water temperature(15~35℃) and roll speed(1.0~3.0m/min) on the thickness cooling rate of jet impingement quenching for ultra heavy steel plate are experimentally investigated. The temperature decrease，temperature gradient and the factors of cooling rate along thickness direction in difference sections of the plate are analyzed. Using the inverse heat conduction method to solve the differential equation of heat conduction， the quenching temperature field and cooling rate of the plate can be calculated. The results indicate that the cooling rate of the 160mm steel core is greater than 1.2℃/s under the jet impingement quenching， and water temperature and roll speed affect not only the average heat transfer coefficient and the type of heat transfer near the plate surface， but also the thickness cooling rate by changing temperature gradient distribution. The thickness cooling rate decreases when water temperature and roll speed increase， and the decreasing range of cooling rate depends on cooling intensity， quenching time and thermal conductivity of the plate.

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Effects of Heat Treatment on Dry Wear Properties of AZ61 Magnesium Alloy

CHEN Qing-qiang， LIU Yu-yang， ZHAO Zhi-hao， ZHU Qing-feng

2017, 38 (11): 1554-1558. DOI: 10.12068/j.issn.1005-3026.2017.11.008

Abstract ( 754 )

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The effects of solution treatment and the aging time of its succeeding aging process on dry wear property of AZ61 magnesium alloys were investigated by using a pin-on-disc apparatus. Wearing rate and friction coefficient were measured under the load of 100 N， sliding speed of 0.78m/s and sliding distance of 1km. The results showed that the coarsen β-phases (Mg₁₇Al₁₂) were dissolved after solution treatment， resulted in the decrease of the hardness of the alloy. The friction coefficient and wearing rate of the alloy increased significantly after solution treatment. Moreover， the AZ61 alloy exhibited a better wear resistance after aging at the temperature of 170℃ with an aging time ranging from 0 to 80h， owing to precipitate large amount of the fine Mg₁₇Al₁₂ phases distributed in the α-Mg matrix.The friction coefficient and wearing rate were the lowest when the aging time was about 20h.Three wearing mechanisms in AZ61 alloys were observed as follows: abrasion， oxidation and delamination.

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Experiment of Microwave-Assisted Grinding on Vanadium Titano-Magnetite

WANG Jun-peng， JIANG Tao， LIU Ya-jing， XUE Xiang-xin

2017, 38 (11): 1559-1563. DOI: 10.12068/j.issn.1005-3026.2017.11.009

Abstract ( 853 )

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According to the characteristics of the complex hard-processing vanadium titano-magnetite (VTM) resources in China， the influence of microwave irradiation on the grinding of VTM was investigated and the features of selective crushing and boundary cracking of VTM under microwave treatment were revealed. The results showed that the ore temperature increased with the increase of the particle size of VTM and the temperature rising capability of VTM was mostly influenced by microwave power. XRD and SEM analyses indicated that after being pretreated by microwave irradiation， a number of intergranular cracks appeared and more monomer was dissociated in VTM.The mass fraction of particle-size grade less than 0.074mm in the ground product increased from 72% to 95% after being radiated by 4kW microwave for 100s.

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Effect of Coke Under Alkali Metal Load on the Droplet Performance of Furnace Charge

CHEN Shu-jun， LIU Kai， LYU Qing， WANG Fu-jia

2017, 38 (11): 1564-1568. DOI: 10.12068/j.issn.1005-3026.2017.11.010

Abstract ( 761 )

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By simulating droplet formation and property in blast furnace， the effect of coke under different alkali metal loads on the droplet performance of furnace charge was investigated. The relations between alkali metal load and the maximum pressure difference (Δp_max) and the droplet eigenvalue (S) value were analyzed， respectively. The results indicate that the coke under alkali metal load affects the charge melt drops performance through catalyzing melting reaction of coke. The morphology of cokes after reaction shows that with the increase of alkali metal load， the number of stomatal on the coke surface increases and the size becomes larger， the erosion of coke surface becomes more severe， the strength of the coke decreases even down to zero， eventually the droplet performance of furnace charge can be affected， which make Δp_max and S deteriorate greatly.

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Semi-analytical Algorithm for Magnetic Field Caused by Arbitrary Surface Electric Current

LEI Hong ， ZHAO Yan

2017, 38 (11): 1569-1573. DOI: 10.12068/j.issn.1005-3026.2017.11.011

Abstract ( 697 )

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It is useful to design delicate electric equipment if magnetic field distribution of surface electric current can be obtained accurately.The magnetic field caused by an arbitrary surface electric current with the same coil width can be calculated by a semi-analytic method. The method is as follows: firstly， the total surface electric current is divided into the trapezoidal and curved surface electric current segments， and then each curved surface electric current segment is further fitted by several trapezoidal segments. Numerical method is applied to give the analytical solution or one-dimensional integral for magnetic field caused by all trapezoidal segments. Finally， the magnetic field caused by the total surface electric current can be obtained by the summation of the segment vectors and solutions. However， some singularities can be arise when a trapezoidal segment turns to a right-angled trapezoidal or a rectangular one， the field point is inside the trapezoidal segment or at the top and bottom base lines of the trapezoidal segment， and the four singularities are the vertices of the largest square inside the trapezoid. Fortunately， these singularities can be eliminated by some mathematical transformation.

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Effects of Preparation Parameters on Oxygen Storage Capacity of YBaCo₄O_7+○δ at Medium and Low Temperature

YU Qing-bo， WANG Tuo， YAN Zi-wen， LI Xin-hui

2017, 38 (11): 1574-1578. DOI: 10.12068/j.issn.1005-3026.2017.11.012

Abstract ( 702 )

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A series of YBaCo₄O_{7+ ○δ○} oxygen carriers were synthesized by solid state reaction method and sol-gel method with different preparation parameters. The phase composition of the samples were analyzed by X-ray diffraction. The effects of preparation parameters on the oxygen storage capacity of Y114 phase at medium and low temperature were investigated by means of thermogravimetry. The experimental results show that the oxygen storage capacity of Y114 phase prepared by the solid state reaction method is higher than that of the one prepared by sol-gel method and the Y114 phase calcined for 20h has a better performance. The δ (nonstoichiometric oxygen) of Y114 phase is 0.89， where the sample is synthesized by the solid state reaction method， calcined at 1150℃ for 20h and furnace cooling， while the δ becomes 0.83 where it is synthesized by the sol-gel method， calcined at 1050℃ for 20h and cooled in air.

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Reliability Analysis of Rolling Bearing Clearance Based on Sparse Response Surface and Polar Transformation

LI Hao-chuan， SUN Zhi-li， FENG Ji-lu， XU Yu-hao

2017, 38 (11): 1579-1583. DOI: 10.12068/j.issn.1005-3026.2017.11.013

Abstract ( 594 )

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A sample selecting method was proposed based on polar transformation， and reliability analysis of rolling bearing clearance was performed combining the method and sparse response surface. In every step of response surface construction， the critical samples were added and fitted according to the clustering feature and distinguishability of safe and failure classes of samples in a plane after polar transformation. The most significant terms of polynomial response surface were chosen according to error prediction criteria and cross-validation method. The limit state function of rolling bearing clearance reliability problem was built comprehensively considering the factors of interference fit， temperature variation and centrifugal force， and the working clearance was calculated employing the finite element method. Finally， the reliability of bearing clearance was calculated based on the explicit style of limit state function. This study provides theoretical basis for rolling bearing design and an efficient way for analyzing implicit reliability problems with multiple dimensions.

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Research on Fluid-Solid Interaction Finite Element Simulation of a Fermentation Stirring Device

GONG Ya-dong， GAO Zhi-zhou， WEN Xue-long

2017, 38 (11): 1584-1589. DOI: 10.12068/j.issn.1005-3026.2017.11.014

Abstract ( 662 )

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Towoard the bearing capacity design issue for the stirring shaft， the torque， deformation and the stress situations were studied based on computational fluid dynamic simulation and fluid-structure interaction analysis by working with various viscosity materials， for the multi-layer stirring and fermentation machine for high viscosity material. The strength-safe viscosity limits and range are calculated according to the torque force of the stirring device， as well as the torque of stirring device under different filling height was analyzed. The results indicated that the on-paddle torque in the first layer is the largest， and the largest deformation happens in the finally the sixth layer. Besides the maximum stress occurs in the shaft segment between the short shaft and the first layer stirring paddle. The safe viscosity limit is 205Pa·s. The height variation of the filling material has little effect to the torque in the stirring device and the optimum heitht range is 100~150mm from the material surface to the top of stirring tank.

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Analysis for the Influence of Industrial Noise on Brain Cognition of Workers

QI Zuo-qiu， WANG Hong， CHANG Wen-wen， WANG Qiao-xiu

2017, 38 (11): 1590-1595. DOI: 10.12068/j.issn.1005-3026.2017.11.015

Abstract ( 732 )

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The influence on brain of subjects from industrial noise is analyzed to provide objective physiological basis for the hearing protection planning， annoyance ease and ergonomic design in the industrial enterprises. EEG signals are recorded using 32-electrode-device from 10 college students under the condition of industrial noise and quiet. The signal data was preprocessed by SCAN software， including removing eye electricity， wake， filtering， segmented merger etc. The ERP for 500ms were analyzed and the N1 (N100) and P2 (P200) amplitude value of brain topographic map were mapped. The analysis results of ERP shows that amplitude of N1 decreased significantly while the amplitude of P2 raised distinctly on the contrary. High SPL industrial noise can lead to attention distraction， annoyance， emotional tension， and interference of cognitive ability.

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Study of the Landing Dynamics of Carrier Based Helicopter Under Complex Sea Conditions

WANG Qian， ZHAO Ding-xuan， WEI Hai-long， ZHAO Ying

2017, 38 (11): 1595-1600. DOI: 10.12068/j.issn.1005-3026.2017.11.016

Abstract ( 699 )

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The landing dynamics of the carrier based helicopter was studied. Firstly， the mathematical model of random sea wave signals is presented， and the ship rocking is analyzed using super position principle and the response amplitude operator (RAO).Then， the dynamic model of helicopter fuselage is established using the Lagrange equation with dissipation energy.Also， landing dynamics of the carrier based helicopter is simulated combining the classical ship model and the carrier based helicopter dynamic model.The Runge-Kutta method is used for calculating the dynamic model， and the dynamic model is verified with Matlab.

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RBF Network Adaptive Control Based on SMC Compensation for Six-axis Manipulator

WANG Hong， ZHENG Tian-qi

2017, 38 (11): 1601-1606. DOI: 10.12068/j.issn.1005-3026.2017.11.017

Abstract ( 795 )

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A RBF neural network adaptive control based on sliding mode control compensation is proposed， and applied to the six-axis robot manipulator， to achieve high-precision position tracking and rapid approaching speed in the case of model uncertainty. Sliding mode control is adopted as auxiliary for system robust compensation and fuzzy control is used for real-time switching gain changing to make the uncertainties better， in order to keep the system′s stability toward the influence of friction， external interference errors and parameter changes. Adaptive laws weights were adjusted constantly online， and Lyapunov theorem was used to prove the stability. The simulation result indicated that a faster convergence rate and stronger robustness can be acquired with the proposed control algorithm， comparing with other research. It also shows that in reality， significant difference exists between the modeling parameters and the actual values.

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Optimization Design of Aerodynamic Shape of Splitter Mixing Exhaust System

XIE Yi ， LIU Kun

2017, 38 (11): 1607-1612. DOI: 10.12068/j.issn.1005-3026.2017.11.018

Abstract ( 539 )

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An integrated optimization design method for nozzle configuration and splitter radial location was proposed using B-spline curve， computational fluid dynamics method and improved particle swarm optimization. Then the proposed method was implemented to optimize a splitter mixing exhaust system. The results indicate that the optimized system has better mass flux distribution than the original model. The difference of bypass ratio between optimized model and design value is 2.8%. In aerodynamic performance aspect， the thrust of optimized splitter mixing exhaust system is 1.061 times as the original model， and the total pressure recovery coefficient increases to 0.995. Under the off-design conditions， compared with the original model， the total pressure recovery coefficients of optimized model increase respectively by 0.7% and 0.4%， and the thrust increases respectively by 1.2% and 2.7% .

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Research on Loudness of Radiation Noise of a Constrained-Layer Damping Oil Pan

LIU Rui-jun， HAO Zhi-yong， ZHENG Xu， XIONG Fei

2017, 38 (11): 1613-1617. DOI: 10.12068/j.issn.1005-3026.2017.11.019

Abstract ( 606 )

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The liquid-solid coupling model of a constrained-layer damping oil pan as well as the infinite model of the radiation acoustic field were established. The vibration accelerations of bolts， which were loaded in bolt holes for calculating the radiation acoustic field， were measured. The simulated value of sound pressure was acquired at the point which is vertically 10cm from the bottom center of the oil pan， and the value is extremely consistent with the measured value in the range of 500 to 3000Hz， proving preciseness of the acoustic calculation. Total value of A-weighted sound pressure level of radiation noise and the loudness value were respectively regarded as the objectives to optimize the oil pan. The results indicated that the noise with less sound pressure may make the noise sound louder， and only if the sound quality parameters are considered as optimization objectives， the NVH performance can be consequently improved effectively. Finally， the adaptive simulated annealing algorithm was adopted to optimize the thickness of the layers of the constrained-layer damping oil pan， with the loudness of radiation noise as the optimization objective. The result shows that the loudness value declined by 27.3%， reduced 40.0 sone and the mass can be reduced by 21.2%， and the NVH performance is promoted obviously.

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Study on Model Free Adaptive Sliding Mode Controller for Artificial Muscle Actuators

YANG Hui， HAO Li-na， SUN Zhi-yong， CHEN Yang

2017, 38 (11): 1618-1622. DOI: 10.12068/j.issn.1005-3026.2017.11.020

Abstract ( 800 )

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The traditional control strategies for artificial muscle actuators based on the control object model have drawbacks such as complex in control laws， too many control parameters which is tedious to adjust， and having poor universality. Thus， a model free adaptive sliding mode controller (MFASMC) was designed based on the gradient method and proved in stability. Then， the new algorithm was simulated to contorl the identification models of IPMC(ionic polymer metal composite) and PAM(pneumatic artifical muscle) respectively. The results proved that the control parameters can be adjusted online by the new MFASMC algorithm rapidly， by designing the control parameters regulation rules. In this way， MFASMC makes the modeling process is not necessary. Moreover， the good control effects can be obtained for various artificial muscle actuators with no need to adjust any control parameters. Therefore， MFASMC has good adaptability and universality.

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Numerical Simulation on the Mechanism of Fault Reactivation Induced Water Inrush Associated with the Excavating Process

SHI Wen-hao， YANG Tian-hong， LIU Hong-lei， ZHAO Yong-chuan

2017, 38 (11): 1623-1627. DOI: 10.12068/j.issn.1005-3026.2017.11.021

Abstract ( 661 )

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A case of water inrush through fault induced by mining in Zhongguan iron mine was studied by the finite element simulation. The fault stress and damage zones were analyzed to study the mechanism of fault reactivation-induced water inrush. The simulation results illustrate that the excavating process is the cause of damage zones initiation， accumulation， extension and coalescence. The fault shear stress concentration moves from the top downward to roof gradually. The compression-shear damage zone in the fault changes to tension-shear damage zone and grows gradually. When the fault is fully exposed， the connected damage zone provides a channel for the groundwater outburst and finally causes the inrush incident. Therefore， the conductivity of the natural waterproof fault cannot be completely confirmed by horizontal cover hole before excavations. To be safe， more acclivitous cover holes should be drilled to probe the conductivity of the fault in the higher positions for the further confirmation.

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Numerical Simulation of the Flow Solid Coupling Effect in the Seam Roadway Pre-exhaust Gas Zone

ZHANG Wei， XU Kai-li， LEI Yun

2017, 38 (11): 1628-1633. DOI: 10.12068/j.issn.1005-3026.2017.11.022

Abstract ( 527 )

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The gas emission law during excavation in coal mining is the fundamentals of prevention and control of gas disasters. For the gas emission law in the study， there is no accurate method to determine the problem of pre-exhaust gas zone width of seam roadway. Based on the theory of gas flow and coal and rock deformation， the gas flow equation of gas-containing coal and rock and the coal and rock roadway deformation equation were established， the flow solid coupling mathematical model of the seam roadway pre-exhaust gas zone was established as well. The Qinshui mining area excavated roadway was taken as an example of numerical simulation to obtain the characteristics of temporal and spatial evolution of gas-containing coal and rock roadway damage. Based on the tracing principle， the method of measuring the pre-exhaust gas zone width of the seam roadway was proposed， and the measured results were consistent with that of the numerical calculation. The research results help to solve the problem of prediction accuracy of gas emission in coal working face.

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Mineral Resource Quantitative Prediction Based on LS-SVM Combining with Bayesian Inference

HAN Chang-ik ， WANG En-de， XIA Jian-ming， CHOE Sun-chol

2017, 38 (11): 1633-1636. DOI: 10.12068/j.issn.1005-3026.2017.11.023

Abstract ( 641 )

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In the mineral resources quantitative prediction using the least squares support vector machine (LS-SVM)， precision of results are influenced by the selection of its parameters. The prediction method based on the LS-SVM combining with Bayesian inference is proposed and it is also compared with weights-of-evidence (WofE) method. During the training process， the optimized parameters of LS-SVM are chosen by Bayesian inference method， which can build the optimized model for the mineral resources quantitative prediction. The results show that the proposed method not only overcomes randomness and limitation of its optimal parameter selection， but also increases the accuracy of prediction by exporting the prediction result in the form of posterior probability.

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Superfine Dust Removal Performance in Vertically Quadrate Wet Electrostatic Precipitation

HAO Wen-ge， LIU Sai， ZHANG Xin-an， CAI Ji-ying

2017, 38 (11): 1637-1642. DOI: 10.12068/j.issn.1005-3026.2017.11.024

Abstract ( 710 )

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In order to verify removal performance of superfine dust in the vertically quadrate wet electrostatic precipitation(WESP)， a WESP test system was set up in accordance with the practical engineering application requirements. In the experimental system， the influence of factors on the dust removing effect were tested such as the wind speed， the voltage between the electrodes， the electric field length and the dust concentration of fine dust in the simulated flue gas. The test results showed that when wind speed was 2.6m·s^-1， voltage was up to 60kV， field length was 6m and dust concentration of fine dust in the simulated flue gas was low to 50mg·m^-3， the dust removal efficiency in the vertically quadrate electrostatic precipitation dust showed high to 96.66%; also， the removal efficiency of dust particle whose diameter was equal to or less than 2μm still achieved 93%.

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Rock Quality Evaluation of Dam Foundation Based on Component and Cloud Model Weighting Method

CAO Chen， LI Hui-zhong， CHEN Jian-ping， ZHENG Lian-jing

2017, 38 (11): 1643-1647. DOI: 10.12068/j.issn.1005-3026.2017.11.025

Abstract ( 671 )

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This study focused on the dam foundation rock quality evaluation. Six evaluation indicators involving saturated uniaxial compressive strength， structural plane spacing， RQD， integrality coefficient， acoustic longitudinal wave velocity and ground stress correction coefficient were taken into consideration. Based on the component weighting method and cloud model， the Jinsha Xulong dam foundation rock mass was taken as a case. The optimal sequence diagram method and entropy value method were combined by the preference coefficient method to overcome the disadvantages of using subjective and objective weighting method alone. The rock mass quality evaluation indicators clouds were established based on the digital characteristic values. Then the certainty of each indicator was calculated. The corresponding quality degree is the rock mass quality degree. The cloud model results were compared with traditional BQ method results and the extension theory results. The cloud model has stronger controllability and higher classification accuracy， which is able to express the comprehensive uncertainty of rock quality.

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Experimental Study on Tin Recovery Based on Membrane Electrodeposition from Metal Fractions of Waste Printed Circuit Boards

YANG Jian-guang， CHEN Bing， LEI Jie， LI Shu-chao

2017, 38 (11): 1648-1653. DOI: 10.12068/j.issn.1005-3026.2017.11.026

Abstract ( 794 )

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A new hydrometallurgical progress based on membrane electrodeposition was proposed to effectively extract tin from metal fractions of WPCBs(waste printed circuit boards). Leaching experiment results showed that under the conditions of temperature 40℃， Sn⁴⁺ concentration 50g/L， HCl concentration 4mol/L， liquid (ml) to solid (g) ratio 5∶1 and cycle 3 times， the leaching efficiency of tin was about 96%， and the resultant Sn²⁺ concentrated in the leach solution was 68.58g/L. The electrodeposition tests indicated that under the condition of current density 200A/m²， temperature 35℃， H⁺ concentration 3mol/L and Sn²⁺ concentration 40~100g/L， a compact and smooth cathode tin layer can be obtained after 8h electrodeposition. The current efficiency was 97.51% and the electric consumption was less than 1200kW h/t.

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Properties of Two-Well Dissolution Cavity-Building Expansion with Small Well Space

REN Song， TANG Kang， YI Liang， LIU Wei

2017, 38 (11): 1654-1658. DOI: 10.12068/j.issn.1005-3026.2017.11.027

Abstract ( 720 )

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The experimental device of two-well dissolution cavity-building with a small spacing was set up， and the law of cavity volume expansion in different casing arrangement was studied by model test. The results indicate that cavity volume growth rate of only injecting the inlet is greater than that of the other two ways， and the cavity volume reaches to the biggest eventually. Different casing arrangements have little effect on the dissolution rate of salt wall as well as the dissolution angle in the bottom of the cavity. Injecting the two wells at the same time and injecting the inlet only form a cavity of a shape of “ship”.There will form a cavity of two “towers” in the top and a large cavity at the bottom when injecting the oil. Compared with the single well technique， two-well dissolution cavity-building expansion with a small well spacing technology has a great advantage at the early stage.

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Mechanical Properties of the Total Tailing Cemented Backfilling Impacted by Cement-Sand Ratio Under High Strain Rate

YANG Wei， TAO Ming， LI Xi-bing， LI Guo-ping

2017, 38 (11): 1659-1663. DOI: 10.12068/j.issn.1005-3026.2017.11.028

Abstract ( 667 )

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In order to study the dynamic mechanical behavior of the total tailing cemented backfilling under the mining disturbance impacted by cement-sand ratio， three groups of different cement-sand ratio specimens of total tailing cemented backfilling were precasted， and the precast specimens under uniaxial impulse by using the  50 mm SHPB experimental system was tested.The test results show that the total tailing cemented backfilling has strong reflection and damping effect on elastic wave propagation.At the high strain rate， specimens exhibit the behavior of rapid softening and the softening specimens reach to peak strength at around 18 μs.The dynamic compressive strength increases with an increase instrain rate. The higher cement-sand ratio， the greater the ultimate dynamic compressive strength. At the same strain rate， the dynamic compressive strength of the specimens decreases with the increase of cement content.At the same strain rate， the lower the cement content， the more severely the specimens fail with the form of crushing destruction.

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Thermal Stress Analysis of CRTSII Track-Slab of High-Speed Railway Under a Uniform Cooling Condition

ZHAO Lei， SUN Lu， SUN Wei， ZHAO Guo-tang

2017, 38 (11): 1664-1668. DOI: 10.12068/j.issn.1005-3026.2017.11.029

Abstract ( 771 )

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A new calculation model of track-slab of high speed railway about temperature stress was established based on rail—track-slab—steel bar linear slip constitutive equations， and the analytic expression were derived using Laplace transform method.The influence of the parameters including reinforcement ratio， fastener buckle pressure and plate friction on the crack spacing and the changing characteristics of internal force and displacement of the track-slab under uniform cooling were studied with analytic expression. Finally， taking the CRTSII track plate under 30℃ cooling conditions with the respect to the Beijing—Shanghai high-speed railway as an example， the stress and displacement distribution of slab with the crack length and reinforcement ratio were calculated. It can be concluded that temperature stress of CRTSII track-slab can be analyzed effectively using the method and provides theoretical basis of design for ballastless track structure.

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Special Curves in 3-Dimensional Euclidean Space

YUAN Yuan， LI Jing， LIU Hui-li

2017, 38 (11): 1669-1672. DOI: 10.12068/j.issn.1005-3026.2017.11.030

Abstract ( 866 )

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The properties of center locus of osculating sphere and the rectifying circle of curves were studied by using the theory and the properties of moving frame. First， the relationships between curves and the center locus of osculating sphere of curves were studied. Based on curvature and torsion， the figure of the center locus of osculating sphere of curves was obtained. And the center locus of osculating sphere of curves was generalized helix， Bertrand curves， Mannheim curves， rectifying curve and spherical curve， respectively， when curvature and torsion satisfied certain relation. Then， based on the intersection of osculating sphere and rectifying plane， the rectifying circles were obtained， and the properties of the center locus of rectifying circles were studied.

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