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15 March 2016, Volume 37 Issue 3 Previous Issue    Next Issue
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Information & Control

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Sensory Effect of Evanescent Wave in the Tapered Optical Fiber RI Sensor CAI Lu， ZHAO Yong， WANG Qi， HU Hai-feng 2016, 37 (3):  305-309.  DOI: 10.12068/j.issn.1005-3026.2016.03.001 Abstract ( 634 )   HTML   PDF (580KB) ( 1094 )   The internal mechanism about the effect of evanescent wave in tapered modal interferometer was investigated theoretically. The relationships between the power of evanescent wave and the effective RI of cladding modes were calculated， and the simulated interference spectrum shifted with external RI was ohtained.It can be theoretically proofed that the generation of evanescent wave provides a vital role in improving the sensing sensitivity of tapered optical fiber RI sensor. In addition， effects of the taper shape， such as outline， waist radius and taper length， on the power of evanescent wave attenuated in taper region were investigated based on the evanescent wave absorption spectroscopy， which is helpful to optimize the taper shape and improve the sensitivity of RI measurement. Finally， the experiment of RI measurement by tapered modal interferometer has been carried out to verify the accuracy of the theory. References | Related Articles | Metrics

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Transformer Maintenance Strategy Based on Fuzzy TOPSIS Method ZHANG Cui-ling ， WANG Da-zhi， Ning Yi ， JIANG Xue-chen 2016, 37 (3):  309-313.  DOI: 10.12068/j.issn.1005-3026.2016.03.002 Abstract ( 507 )   HTML   PDF (302KB) ( 726 )   Transformer maintenance strategy decision is a decision-making problem of hybrid multiple attribute index related to coexistence of quantitative indicators and qualitative indexes. The fuzzy comprehensive evaluation analysis model of the transformer maintenance strategy was set up by using fuzzy TOPSIS， and the decision-making problem of hybrid multiple attribute index was solved. Through calculating the relative closeness degree to determine the transformers operation status， the transformer maintenance strategy could be determined by using the proposed method. In addition， the proposed method not only can monitor transformers operation status，but also can directly determine the best one from various maintenance strategy for a transformer using the expert system . The index values of accurate real type， interval type and fuzzy number were classed and judged， then the relative closeness degree of various maintenance strategy was sorted through analysis and comparison， based on which it could be decided to choose which kind of maintenance strategy. The result of the example shows that the method has good effect on transformer maintenance strategy decision. References | Related Articles | Metrics

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Species-Based Genetic Algorithm for Multiobjective Optimization Problems FU Ya-ping， WANG Hong-feng， HUANG Min 2016, 37 (3):  314-318.  DOI: 10.12068/j.issn.1005-3026.2016.03.003 Abstract ( 701 )   HTML   PDF (310KB) ( 772 )   In order to achieve a set of nondominated solutions for multiobjective optimization problems quickly and accurately， a Species-based genetic algorithm for multiobjecitve optimization problems was proposed. Firstly， a certain number of subproblems were developed with the Tchebycheff approach. Then multiple subpopulations were constructed based on the Species mechanism to solve all the subproblems simultaneously， which can improve the exploration and exploitation ability by using multiple individuals to search one optimal solution. Finally， a set of benchmark multiobjective functions were examined， and the experimental results showed that the proposed algorithm can obtain a certain number of nondominated solutions quickly and accurately. References | Related Articles | Metrics

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Analysis Method of Seismic Sequence Based on Node Converging XU Jiu-qiang， SONG Jia， HE Xuan， ZHAO Hai 2016, 37 (3):  319-322.  DOI: 10.12068/j.issn.1005-3026.2016.03.004 Abstract ( 558 )   HTML   PDF (517KB) ( 597 )   Based on space-time influence domain， an earthquake network was built， which had small-world and scale-free characteristics of complex network. The Sichuan seismic data were chosen between 1990 and 2010， most of which distributed on the Longmenshan fault. After node converging on the earthquake network， several seismic sequences from nodes were obtained， which mainly belonged to foreshock-mainshock-aftershock type. Through studying the energy changing of seismic sequences， the results indicated that a single earthquake’s energy changing does not show the law， but the sum energy of sequences with a certain size time window has periodicity change， and the energy center distributes on the Longmenshan central fault zone. All of these researches show that there is an important significance to recognize the regularity of earthquake using analysis method of seismic sequence based on node converging. References | Related Articles | Metrics

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Markov Location Prediction Based on User Mobile Behavior Similarity Clustering LIN Shu-kuan， LI Sheng-zhi， QIAO Jian-zhong， YANG Di 2016, 37 (3):  323-326.  DOI: 10.12068/j.issn.1005-3026.2016.03.005 Abstract ( 757 )   HTML   PDF (312KB) ( 1221 )   GPS trajectories are often sparse due to the sampling points lost or new users appearing， which makes the accuracy of location prediction low based on the data of a single user. To solve this problem， a novel Markov location prediction approach was proposed based on user mobile behavior similarity and user clustering. First， the map was partitioned into various regions based on Voronoi diagram and original GPS trajectories. And then locations were predicted over region trajectories. Second， a new approach was proposed to measure the similarity of users’ mobile behaviors by considering users’ transferring features and regional features. Third，based on the mobile behavior similarity， users were divided into various groups and the first-order Markov model was applied on the groups to predict users’ locations. Therefore， the accuracy of location prediction was improved. The experiments over real GPS trajectory dataset indicate that the proposed method is effective for location prediction. References | Related Articles | Metrics

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Multipath Mitigation of GPS Receivers Based on the C/N○0 Estimation and Wavelet Method GENG Fu-quan， ZHAO Yun， HUANG Zhi-gang 2016, 37 (3):  327-332.  DOI: 10.12068/j.issn.1005-3026.2016.03.006 Abstract ( 567 )   HTML   PDF (834KB) ( 722 )   To mitigate the multipath effects caused by the complex signal reflection of urban application environments in GPS receivers， a multipath mitigation method based on a hypothesis testing wavelet thresholding filter and the carrier-to-noise density ratio (C/N○0) estimation was proposed. This technique was integrated into the code and carrier tracking loops， which estimated the multipath tracking errors by the wavelet thresholding filtering based on the C/N○0 estimation， and then removed the positioning errors in multipath environments by compensating the pseudorange measurements. The simulation tests were conducted in the typical multipath scenario under urban navigation environments， whose results showed that the statistical positioning error can be reduced from 15.95m with the standard receiver processing to 1.75m with the proposed method， which indicated that the proposed method achieves a significant improvement of positioning accuracy without an obvious additional computation load. References | Related Articles | Metrics

Materials & Metallurgy

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Evolution of Morphological Character of Al4Sr Phase Under Different Solidification Conditions LI Lei， XU Si-yang， ZHANG Hai-tao， CUI Jian-zhong 2016, 37 (3):  333-337.  DOI: 10.12068/j.issn.1005-3026.2016.03.007 Abstract ( 624 )   HTML   PDF (1237KB) ( 621 )   Al-20 Sr intermediate alloys were prepared by both mold and suction castings. The morphological evolution of the primary Al4Sr phase under different solidification conditions was investigated by SEM. The results showed that in the mold cast specimens the primary Al4Sr phases are regular and complete block-like shape at 850℃ and are strip-like form with obvious preferential crystallographic growth character at 950℃. In the suction cast specimens， the primary Al4Sr phases are regular and complete block-like shape when the temperature is increased to 850℃， fine bamboo-like shapes in the central and short strip-like and elliptical forms in the peripheral regions when the temperatures are increased to 900℃ and 950℃ and then decreased to 900℃， coarse and fine stripe-like shapes when the temperatures are decreased to 850℃ and 800℃， and coarse stripe-like forms when the temperature is decreased to 750℃， respectively. In summary， solidification conditions have important influence on the morphologies of Al4Sr phase. References | Related Articles | Metrics

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Study on Friction and Wear Properties of High Lead Tin-Bronze Alloy by Centrifugal Casting LIU Yue， CHEN Chao， LYU Wen-ling 2016, 37 (3):  338-342.  DOI: 10.12068/j.issn.1005-3026.2016.03.008 Abstract ( 575 )   HTML   PDF (1099KB) ( 783 )   High lead tin-bronze (ZCuPb22Sn1.5) was produced by centrifugal casting method. The friction and wear properties of the materials were investigated at fixed loads and friction speed，and the wear mechanisms were also analyzed. The results showed that the wear rate increases and the friction coefficient decreases with the increasing the load， the friction coefficient decreases rapidly and then trends to be stable as the loads increases to 120N when the friction speed is below 0.05m/s. Similarly， at the loads of 100N the wear rate increases and the friction coefficient decreases with the increase of the friction speed when the friction speed increases to 0.10 m/s， the friction coefficient decrease rapidly， and then trends to be stable as the friction speed increases to 0.20m/s. Then， with the increase of the fixed loads and friction speed， the solid lubrication film is damaged， the wear of the materials is severe and the wear rate unstably increases. In the process of friction and wear the Pb solid lubrication film on the worn surface is stable， and the materials have good antifriction and lower wear. References | Related Articles | Metrics

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Adaptive Strategy of Short Stroke Control in Tandem Hot Rolling PENG Wen， MA Geng-sheng， CAO Jian-zhao， ZHANG Dian-hua 2016, 37 (3):  343-346.  DOI: 10.12068/j.issn.1005-3026.2016.03.009 Abstract ( 753 )   HTML   PDF (381KB) ( 754 )   The SSC (short stroke control) is a key issue in the width control of the strip head end in hot tandem rolling process. In order to enhance the width precision， an SSC adaptive strategy was proposed， the objective function with the key points of the SSC curve and actual width error curve was founded， and in the process for looking for the optimal solution， the NM(Nelder-Mead) simplex algorithm was used， finally the optimized width compensation curve was received， and the SSC on-line adaptive strategy was realized with the exponential smoothing method. The adaptive strategy was successfully applied to a tandem hot mill， and the application result showed that the width deviation between the head end and the stable part can be controlled within 2.0mm， and the proportion is up to 90 %， which can meet the actual production， and has good application prospect. References | Related Articles | Metrics

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Study on Degradation of Methylene Blue Through Heterogeneous Fenton in Slag Catalyst YANG He， WANG Zhen， HAN Chong， XUE Xiang-xin 2016, 37 (3):  347-351.  DOI: 10.12068/j.issn.1005-3026.2016.03.010 Abstract ( 633 )   HTML   PDF (614KB) ( 702 )   The catalytic degradation of methylene blue (MB) in wastewater were investigated， in which slag and hydrogen peroxide were used as catalyst and oxidation agent， respectively. The results show that the acid dosage plays a vital role in the whole reaction， and the effective degradation is achieved in the condition of a given acid dosage. The removal rate of MB increases first and then decreases with increase of the concentration of hydrogen peroxide. Moreover， the particle size of slag， steel slag dose， and reaction temperature mainly affect the removal rate of MB by affecting the dissolution of Fe. The removal rate of MB can achieve 99.1% under the following experimental conditions: reaction time 60min， the concentration of MB solution 200 mg/L， initial H2O2 concentration 0.000 6， steel slag(45~58μm)dosage 6g/L and reaction temperature 30℃. According to the infrared spectrum of steel slag before and after the reaction， MB is removed by oxidization but not by adsorption. References | Related Articles | Metrics

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Energy Consumption and Smoke and Dust Emissions Analysis of Typical Iron and Steel Production Enterprise LI Xiao-ling， SUN Wen-qiang， ZHAO Liang， CAI Jiu-ju 2016, 37 (3):  352-356.  DOI: 10.12068/j.issn.1005-3026.2016.03.011 Abstract ( 586 )   HTML   PDF (591KB) ( 694 )   Taking a typical iron and steel production enterprise as the research object， based on the practical production data of enterprise， substance metabolism model was constructed by using material flow analysis method (MFA). According to energy use， resource use and pollutant emissions indexes， resources and energy consumption and smoke and dust emissions situation of the iron and steel production enterprises were quantitatively described. The results showed that for enterprises， the total resource consumption per ton of steel of the blast furnace converter’s long process is 208.6t. Fuel consumption is 93.9% of the total energy consumption. The smoke and dust emission per ton of steel is 648.08g， of which sintering and iron-making process make the biggest contribution and account for 45 percent and 36 percent， respectively. The total resource consumption of electric furnace’s short process is 1.31t， of which electrical energy consumption is 96.7% of the total energy consumption and the smoke and dust emissions per ton of steel is 67g. As for processes， the emissions of sintering， coking and iron-making process are 222.50g/t sinter， 118.20g/t coke and 245.27g/t iron. Accordingly the directional advices on energy-saving and emission reduction in enterprises and the adjustment of industrial structure are put forward to reduce the pressure on the environment and realize the sustainable development of iron and steel enterprises. References | Related Articles | Metrics

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Mathematical Model of Adjusting Blast Volume of Blast Furnace Tuyeres LI Yang-long， CHENG Shu-sen， CHEN Chuan 2016, 37 (3):  357-362.  DOI: 10.12068/j.issn.1005-3026.2016.03.012 Abstract ( 704 )   HTML   PDF (788KB) ( 838 )   A mathematical model of adjusting blast parameters of tuyere was built and the formula of tuyere flow resistance was proposed. Based on a domestic 5500m3 BF， the blast volume， velocity and kinetic energy of each tuyere were analyzed， respectively， when the lengths or areas of tuyeres were adjusted at the condition of constant total blast volume. The results showed that the flow resistance of adjusted tuyeres increases with increasing their lengths and decreasing their areas. Therefore， increasing the length of adjusted tuyeres can decrease their blast volume， velocity and kinetic energy. The blast volume of adjusted tuyeres can be also reduced by decreasing their areas. The blast velocity and kinetic energy of adjusted tuyeres can be enhanced when the areas of multiple tuyeres were decreased. What’s more， the formula of critical adjusted tuyere number is put forward. This model can help to master the variation regulations of blast parameters and adjust the parameters of tuyeres quantitatively， which is benefit for stable and smooth work. References | Related Articles | Metrics

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Digestion of Silica from the Potash Feldspar Roasted Clinker LIU Jia-nan， SHEN Xiao-yi， ZHANG Jun， ZHAI Yu-chun 2016, 37 (3):  363-367.  DOI: 10.12068/j.issn.1005-3026.2016.03.013 Abstract ( 757 )   HTML   PDF (659KB) ( 756 )   The digestion of silica in roasted clinker of potash feldspar with Na2CO3 was studied. The influences of digestion temperature， digestion time， stirring intensity， clinker granularity and NaOH concentration on the digestion efficiency of SiO2 were analyzed. The mineralogical structure and microstructures of roasted clinker and residue by digestion were characterized and the process of digestion was analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD) analyzer. The appropriate digestion conditions were concluded as follows: digestion temperature 95℃， digestion time 80min ， stirring intensity 400r/min， clinker granularity 74~89μm and NaOH concentration 0.2mol/L. Under the conditions， the digestion efficiency of SiO2 is up to 99%. Na2SiO3 is joined into solution and K， Al are enriched in residue through digestion， and then they are separated. References | Related Articles | Metrics

Mechanical Engineering

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Gear Tooth Modification Based on Reliability Robust Optimization Design YANG Zhou， ZHANG Jing， ZHANG Yi-min， TAN Xue-fei 2016, 37 (3):  368-372.  DOI: 10.12068/j.issn.1005-3026.2016.03.014 Abstract ( 623 )   HTML   PDF (251KB) ( 680 )   Based on the reliability of higher order moments theory， by integrating optimization design， sensitivity design and robust design， a reliability robust design model of cylindrical gear transmission modification parameters was built and a cylindrical gear modification optimization method which regards modification parameters as the design variables and modification parameter sensitivity and gear quality as the objective function was proposed so as to solve the problem of gear modification parameter determination from the perspective of reliability-based robust design. Apart from that， the effect of the change of tooth modification parameters on gear transmission reliability was studied， whose ideal numerical results were validated and obtained through computer programing. The numerical example showed that the proposed method is a convenient and practical method to improve the amount of gear tooth modification， which can provide a theoretical basis to determine the best gear tooth modification. References | Related Articles | Metrics

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Research and Development of the Prediction Software for Turning Chatter Stability LIU Yu， LIU Ya-chao， ZHANG Yi-min 2016, 37 (3):  373-377.  DOI: 10.12068/j.issn.1005-3026.2016.03.015 Abstract ( 558 )   HTML   PDF (912KB) ( 743 )   In view of the engineering need for predicting chatter with software in metal processing， the hardware and software system for the chatter stability lobe diagram test in the turning process was designed. Some key problems existing in the algorithm of the software were researched. Firstly， the hardware system was built， which was composed of an acquisition card， an acceleration sensor and a modal force hammer. The software system， which was able to obtain FRF (frequency response function) of the tool and stability lobe diagram of a turning machine， was developed. Secondly， the interactive interfaces of acquisition and analysis were designed. The multi-channel high-speed synchronous trigger-acquisition algorithm in FRF testing based on C# language was studied. The class of C# to analyze the chatter stability lobe diagram was developed using the frequency domain analysis method. Finally，the stability prediction of CJ0625 was conducted. The results showed that the predicted results of the software coincide with the experimental results. References | Related Articles | Metrics

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Study of Localization for the Forced Vibration of Mistuned Bladed Disks Based on Engine Orders of Excitation ZHANG Hong-yuan， YUAN Hui-qun， KOU Hai-jiang 2016, 37 (3):  378-382.  DOI: 10.12068/j.issn.1005-3026.2016.03.016 Abstract ( 624 )   HTML   PDF (676KB) ( 700 )   In order to evaluate the effect of localization for various engine orders of excitation and levels of mistuning on mistuned bladed disks， the finite element model of aero-engine compressor’s bladed disks was established. Considering the non-linear contact problem of tenon and mortise， the localization of various engine orders of excitation of mistuned bladed disks was studied by adopting the component mode synthesis method and introducing the relative localization factors. The effect of displacement and strain energy for various engine orders of excitation of mistuned bladed disks was discussed， whose results indicated that the engine orders of excitation have significant effect on frequency， displacement and strain energy. With the increase of engine orders of excitation， the relative localization factors tend to first increase and then drop. References | Related Articles | Metrics

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Structure and Flow Field Analysis of Bearing Cooling Fans of the Circulating Cooling Water Pump in a Nuclear Power Plant WU Ming-zhe， WANG Xiao-dong， SUN De-chen 2016, 37 (3):  383-386.  DOI: 10.12068/j.issn.1005-3026.2016.03.017 Abstract ( 582 )   HTML   PDF (731KB) ( 708 )   The circulating cooling water pump in a nuclear power plant operates in a high temperature environment， and the pump bearing receives a large amount of heat load， so the work reliability is of great importance. To reduce the bearing’s working temperature and ensure its safe operation， a cooling device should be installed in the pump system. The structure of the bearing’s axial flow cooling fan in the pump was proposed， and the optimum design method of the bearing’s axial flow cooling fan in the pump was established. For the fan blades， the optimized calculation using BFGS algorithm was proceeded. A simulation verification of the system was proposed by using FLUENT， whose results showed that the design method is suitable for the bearing’s axial flow cooling fan design in circulating cooling water pumps in a nuclear power plant. References | Related Articles | Metrics

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Sample Classification Method for Green Process Evaluation Based on Fuzzy Clustering WANG Yu-gang， XIU Shi-chao， WANG Ke-yuan 2016, 37 (3):  387-391.  DOI: 10.12068/j.issn.1005-3026.2016.03.018 Abstract ( 547 )   HTML   PDF (388KB) ( 604 )   Due to the uncertainty， multidimensionality and significant difference of the evaluation samples of green process， a novel algorithm of kernel-based fuzzy possibilistic clustering was proposed in order to achieve reasonable sample classification. Kernel fuzzy clustering， possibilistic clustering and subtraction clustering were combined to improve the accuracy of clustering and cluster validity index was used as the classification condition to obtain the optimal classification number. The simulation results showed that this algorithm has good validity and robustness. When the algorithm is applied to classify the evaluation samples of green process， good classification effects are gained， which verifies its practicability. References | Related Articles | Metrics

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Structural Optimization and Test of Double Row Suction Nozzles for Reverse Circulation Drill Bits Used in Complex Formations GAN Xin， YIN Kun， YIN Qi-lei， LI Peng 2016, 37 (3):  392-397.  DOI: 10.12068/j.issn.1005-3026.2016.03.019 Abstract ( 650 )   HTML   PDF (732KB) ( 602 )   The 4 main structural parameters of double row suction nozzles for 150mm reverse circulation drill bits used in multilayer goaf drilling were optimized by orthogonal design method and CFD(computational fluid dynamics) analysis. The analysis results indicated the primary and secondary orders as follows: the inclination angle(θs)， the horizontal deflection angle(θd)， the vertical space (L) and the horizontal space (S)， with the most optimal parameter combination being θs=30°， θd=10°， L=-15mm and S=10mm. At the same time， the 150mm reverse circulation drill bit which adopts the most optimal parameter combination was carried on the multilayer goaf drilling test. The test results showed that the reverse circulation drilling can still be achieved through the first layer goaf， and the rock sample with large particles can be continuously discharged from the borehole bottom to the earth surface. The problem on multilayer goaf drilling and measurement in mines can thus be resolved. References | Related Articles | Metrics

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Flow Filed Simulation and PTV Verification ofthe Hydrodynamic Torque Converter with Adjustable Guide Vanes MA Wen-xing， LIU Hao， LIU Chun-bao 2016, 37 (3):  397-402.  DOI: 10.12068/j.issn.1005-3026.2016.03.020 Abstract ( 534 )   HTML   PDF (962KB) ( 592 )   In order to study the internal flow characteristics of a hydrodynamic torque converter with adjustable guide vanes， the hydrodynamic torque converter with 320mm circular diameter was selected as the research subject. The computational fluid dynamics (CFD) method was applied to calculate the internal fluid flows at different openings and working conditions. Meanwhile， a prototype made by plexiglass was tested by PTV. Then， the internal flows were both obtained using CFD and PTV. Under the same opening， the flow velocity increased with the speed ratio， and the angle between the flow direction and the inlet angle direction of the adjustable guide vane increased as well. In the stall condition， the vortex phenomenon was observed near the vane’s working surface. However， at the no-load condition， the vortex phenomenon emerged in the vane’s non-working surface. The results showed that the numerical simulation method can perform a comparatively accurate prediction of the internal flow characteristics of the hydrodynamic torque converter with adjustable guide vanes in comparison with the test， which can provide a method and basis for the research on its internal flow state， and the performance prediction and design optimization of the hydrodynamic torque converter with adjustable guide vanes. References | Related Articles | Metrics

Resources & Civil Engineering

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Manifold Analysis of the Rock Slope Failure Process Based on the Gravity Increase Method WANG Shu-hong， GAO Hong-yan， ZHANG Zi-shan 2016, 37 (3):  403-407.  DOI: 10.12068/j.issn.1005-3026.2016.03.021 Abstract ( 513 )   HTML   PDF (475KB) ( 705 )   The characteristic of large deformation damage and the existing analysis method in rock slope engineering was considered; meanwhile， based on the structural information collection of the rock slope， a numerical space model of rock slope was established through GeoSMA-3D which was developed by the first author’s team. The numerical model can represent 3D model of rock slope， using the numerical manifold method (NMM) to simulate the process of large deformation in rock slope， based on the block theory and the gravity-increase method which is often used in the finite element method， through increasing the gravity of rock mass continuously， until the “key blocks”begin to slide， and the slope generates large deformation failure. At the same time， the safety factor of slope can be confirmed if the displacement of the most dangerous “key block” increases sharply with the increase of gravity. At last， an example of slope engineering in Liaoning is presented to achieve the characterization of large deformation damage in rock slope， proposing solutions for the slope support， providing a reference for engineering construction and prevention of slope disaster. References | Related Articles | Metrics

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Ore Grade Estimation Based on Multi-gene Genetic Programming HAN Chang-ik， WANG En-de， XIA Jian-ming， LI Gwang-su 2016, 37 (3):  408-412.  DOI: 10.12068/j.issn.1005-3026.2016.03.022 Abstract ( 530 )   HTML   PDF (356KB) ( 682 )   Ore grade estimation is relatively difficult due to the complexity of ore deposit formation process and numerous control factors. Evaluation of ore deposit with low estimation error is crucial in mineral resources development and usage. So far， Kriging， now known as a best estimation method of grade， is based on intrinsic assumption and stationarity about the underlying grade spatial distribution. However， most of ore grade data are spatially sparse， irregularly spaced and have complex distribution， which could result in the Kriging estimation method violating intrinsic assumption and stationarity. This article presented a new method for ore grade estimation based on multi-gene genetic programming and also compared it with ordinary Kriging. The results show that the proposed method makes no assumptions about the spatial distribution of grade data， the condition of implementing ore body grade prediction is simplified， and it can achieve better prediction effect. So， the proposed method can be used to estimate ore grade for complex ore deposit. References | Related Articles | Metrics

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Zircon U-Pb Dating and Petrogenesis of the Baiyingaolao Formation Rhyolites in Chaihe Area， Great Xing’an Range SI Qiu-liang， CUI Tian-ri， WANG En-de， DING Shu 2016, 37 (3):  412-415.  DOI: 10.12068/j.issn.1005-3026.2016.03.023 Abstract ( 624 )   HTML   PDF (475KB) ( 714 )   Zircon U-Pb istopic dating and geochemical analysis were used to study the formation age and petrogenesis of the rhyolites in Baiyingaolao Formation. LA-ICP-MS dating results show that the Baiyingaolao formation rhyolites in Chaihe area form in early cretaceous from 129 to 137Ma. The geochemical study results show that the rhyolites have the characteristic of high silicon and rich alkalis， poor calcium and magnesium. The total REE amount ranges from 121.35×10-6 to 194.92× 10-6. Fractionation of LREE and HREE is obvious［m(La)/m(Yb)N=12.2~21.7］， and Eu has negative anomalies(δEu=0.39~0.61). The trace elements are characterized evidently by enrichment of Rb，Ba，Th，K and depletion of Nb，Sr，P，Ti. Original magma of Baiyingaolao formation rhyolites is chiefly derived from partial melting of up crust rocks. References | Related Articles | Metrics

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Experimental Study of Ilmenite Beach Sands Tailings Flotation DENG Chen-xiong， YAO Jin， YIN Wan-zhong， YIN Lin-lin 2016, 37 (3):  416-420.  DOI: 10.12068/j.issn.1005-3026.2016.03.024 Abstract ( 633 )   HTML   PDF (610KB) ( 720 )   A series of flotation experiments on ilmenite placer tailings in Beihai area， Guangxi Province were performed and the ilmenite placer tailings were obtained through gravity separation and magnetic separation. The experimental results showed that Pb(NO3)2 activates ilmenite because Pb2+ has specific adsorption on ilmenite and thus the capacity to collect ilmenite by sodium oleate is increased. The sodium silicate and sulfuric acid were used as regulators， Pb(NO3)2 was used as activator and sodium oleate was used as collector. Under the conditions of sulfuric acid(900g/t)，sodium silicate(400g/t)，Pb(NO3)2(30g/t)，sodium oleate(450g/t)，the ilmenite concentrate recovery of 54.61% and the TiO2 grade of 39.55% can be obtained by a closed flotation circuit of one rough and two concentrations. References | Related Articles | Metrics

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Research on Controlling MBR Membrane Fouling by Electro-Coagulation QIAN Guang-sheng， HU Xiao-min， CHEN Wen-xi， QI Chong-yang 2016, 37 (3):  421-425.  DOI: 10.12068/j.issn.1005-3026.2016.03.025 Abstract ( 619 )   HTML   PDF (639KB) ( 637 )   Filtration characteristics of the submerged electric coagulation membrane bioreactor(SECMBR) membrane was investigated， function and mechanism of controlling MBR membrane fouling by electrocoagulation was discussed. The results show that the extracellular polymers (EPS)， soluble microbial products (SMP)， ζ potential and sludge particle size are the important influence factors of membrane fouling. Membrane fouling of SECMBR is much less than that of SMBR. In the SECMBR， the in situ dissolved iron ion combines with EPS which can enhance flocculation and alleviate pollution of cake layer. Electrocoagulation can reduce SMP and EPS secreted by unit volume activated sludge in SECMBR， and alleviate membrane pollution. SECMBR reduces the proportion of protein which is main pollution in EPS and SMP， and reduces membrane pollution. ζ potential has a negative correlation with Rc. Correlation degree is -0.7988 and -0.5574 in SMBR and SECMBR. Under the effect of electric field and iron ion， the ζ potential absolute value is reduced， and membrane pollution is alleviated. References | Related Articles | Metrics

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Thermogravimetric-Mass Spectrometry Analysis and Pyrolysis Kinetic of Rice Husk and Rice Straw YAO Xi-wen， XU Kai-li， JIA Yan-qiang， ZHANG Xiu-min 2016, 37 (3):  426-430.  DOI: 10.12068/j.issn.1005-3026.2016.03.026 Abstract ( 668 )   HTML   PDF (589KB) ( 680 )   In the nitrogen atmosphere， thermogravimetry-mass spectrometry(TG/MS) was used in combination to compare the pyrolysis behavior of rice husk and rice straw at the heating rates of 5℃/min and 20℃/min， and the release rule of small molecule gas (CO，CO2，CH4，H2) product with the change of temperature and heating rates was obtained. The results show that the pyrolysis process of rice husk and rice straw can be divided into dewatering and drying warm-up solution stage， volatile component precipitation fast pyrolysis stage and residue pyrolysis carbonization stage. The total weight loss rate of rice straw pyrolysis is about 75%， while rice husk is about 55%， and the index value of rice straw pyrolysis characteristics is higher than that of rice husk. The release intensity of ion current of main biomass gas composition (CO， CH4 and H2) in the rice straw pyrolysis process is obviously higher than that of rice husk. The pyrolysis kinetic parameters were calculated by using Coats-Redfern method. The apparent activation energy and volatile component initial precipitation temperature of rice straw are lower than those of rice husk， which accord with the results of experiment， and indicate that the pyrolysis performance of rice straw is better than that of rice husk under uniform conditions. References | Related Articles | Metrics

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Simulation Analysis of Suspended Sediment Motion Process WU Feng-yuan， FAN Yun-yun， LIANG Li， SUN An-dong 2016, 37 (3):  431-435.  DOI: 10.12068/j.issn.1005-3026.2016.03.027 Abstract ( 566 )   HTML   PDF (767KB) ( 946 )   In order to realize the simulation analysis of suspended sediment motion process， single-fluid model combined k－ε turbulence equation and suspended sediment transport equation was solved by finite volume method. Numerical simulation on two experimental cases was performed and the calculation results agreed well with two experiment results， verifying the effectiveness of the single-fluid model. Then， numerical simulations on suspended sediment up and down motion process in the two experiments were performed. The results showed that sediment run 24s and 35s from the beginning up to a steady state and from the beginning down to a steady state respectively. It is indicated that the single-fluid model is effective to simulate motion process of suspended sediment. It can provide a scientific reference and basis for the study of water and sediment in river coastal engineering. References | Related Articles | Metrics

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Analysis of Subgrade Stability in Karst Area Based on Variable Weight Theory-Uncertainty Measurement Method KANG Qian， WANG Xin-min， PU Hao， WANG Shi 2016, 37 (3):  435-439.  DOI: 10.12068/j.issn.1005-3026.2016.03.028 Abstract ( 484 )   HTML   PDF (449KB) ( 660 )   In order to study the stability of subgrade in karst area， the analysis model of uncertainty measurement was established based on sixteen indexes having the greatest impact on the karst subgrade stability. Also， the uncertain measurement functions of all indicators were established. Each index weight was calculated by using variable weight to avoid the “state out of balance” phenomenon caused by constant weights evaluation. Finally， the risk grade prediction of subgrade stability was made according to grade determination based on confidence identification criteria. This model was applied to the highway reconstruction project in Shimen City Hunan Province. The results showed that the risk grade of 1# subgrade and 2# subgrade were Ⅳ and Ⅲ respectively. Namely， the risk grade of 2# subgrade is higher. The results agree well with the actual engineering. The method can provide a new way for subgrade stability analysis and a reference to subgrade design and construction. References | Related Articles | Metrics

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Goafs′ Risk Discrimination Based on Improved TOPSIS Coupled with GA-BP XIE Cheng-yu， LUO Zhou-quan， JIA Nan， WANG Wei 2016, 37 (3):  440-445.  DOI: 10.12068/j.issn.1005-3026.2016.03.029 Abstract ( 556 )   HTML   PDF (450KB) ( 636 )   According to the complex process and low accuracy of goaf area risk discrimination， the improved TOPSIS coupled with neural network was proposed. Firstly， the TOPSIS method was improved and used on goaf area in order to enhance the objection and accuracy of sample goafs’ risk discrimination. Absolute ideal point and improved fuzzy analytic hierarchy process (IFAHP) objective were respectively used to avoid the reverse phenomenon caused by the change of ideal point and weights. And risk grade division was realized through different instability degree interval threshold value of discrimination index. The improved TOPSIS method was used to risk discrimination of 100 groups goaf area samples in a certain mine and results were validated. Then， in order to simplify the discrimination process， the improved TOPSIS and GA-BP neural network were combined effectively. Calculating neural network model was trained by the 100 groups sample data which were discriminated by improved TOPSIS， the 5 groups were discriminated by the model， and the discrimination results agree with the facts. The study results not only enhance the objection of goaf area risk discrimination， but also provide a new thought for simplifying the discrimination process and expand the engineering application in field. References | Related Articles | Metrics

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Relationship Between AC Electrical Resistivity and the Degree of Soil Chemical Weathering LIU Jing-shuo， CHEN Yu-long， NIE Wen， NING Guo-guo5 2016, 37 (3):  446-451.  DOI: 10.12068/j.issn.1005-3026.2016.03.030 Abstract ( 596 )   HTML   PDF (710KB) ( 599 )   By using alternating current(AC) bridge， the effects of the water content and electric current frequency on the electrical resistivity of soils were studied to investigate the relationship between resistivity and soil chemical weathering index (CWI). The test results show that the electrical resistivity of soils decreases with the increase of water content and electric current frequency. When the water content is relatively low， the electrical resistivity decreases very sharply with the increase of water content， but turned slowly at relatively high water content. However， the electrical resistivity has only a smaller reduction with the increase of the electric frequency. Based on the viewpoint of that the weathering degree is positively related to the electric resistivity， the relationship between resistivity and chemical weathering index was established， and the computing method for fitted parameters was given. A comparison between CWI predicted by fitted equation and actual CWI was made to show its reliability. The electrical resistivity can provide reference for the evaluation of the degree of weathering. References | Related Articles | Metrics

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Geometric Characteristics of TJ-1 Lunar Soil Simulant Particles LIN Cheng-xiang， LING Dao-sheng， ZHONG Shi-ying， JIANG Zhu-jin 2016, 37 (3):  451-456.  DOI: 10.12068/j.issn.1005-3026.2016.03.031 Abstract ( 598 )   HTML   PDF (554KB) ( 699 )   The geometric characteristics of particle is an important physical property of granular material， as well as a principal aspect in determining their mechanical properties. The TJ-1 lunar soil simulant particles used in soft landing model tests were scanned and photographed by using a stereo microscope. Then， a digital imaging processing software was used to statistically analyze the geometric characteristics of particles of each grain size group， and aspect ratio， circularity and roundness of particles were obtained to provide the experimental data for further research of the relationship between geometric characteristics of particles and soil physical and mechanical properties. The research results show that the TJ-1 lunar soil simulant particles have irregular structures of corners， cheicers and sawtooth. Consequently， the surface of particles is relatively rough. Big size particles have obvious honeycomb-like pore structure. The shape of particles differs from each other， the main shapes are long striped， quasi-triangle and quasi-quadrangle. Finally， the geometric characteristics of TJ-1 lunar soil simulant particles is compared to the one of real lunar soil particles. References | Related Articles | Metrics