08 May 2014, Volume 32 Issue 13

    

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  Design of Mobile Robot Based on Predefined Path

  SHI Wenzao, WANG Ping, ZHANG Jiannan

  journal1. 2014, 32(13): 15-18. https://doi.org/10.3981/j.issn.1000-7857.2014.13.001

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  The existing problems of motion path planning are analyzed. A design scheme based on predefined path is proposed for a mobile robot of full range movement to achieve its self-adaption ability of the environment. The structure of the system and main function modules are introduced. The system is composed of a mobile robot, wireless remote controller, and various sensors including hall sensor, the infrared obstacle avoidance sensor and electronic compass to realize the robot's accurate move, path learning and information storage. The system workflow is elaborated from the record mode and moving mode. The test results show that the mobile robot can carry various equipment and actualize the movement according to the predefined path and return. It is good for the application of monitoring and collection in a smart home environment.
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  Research on Damage to Supersonic Anti-Ship Missile Engine Cabin by APCR

  JIANG Yingzi, WANG Weili, HUANG Xuefeng, FU Lei

  journal1. 2014, 32(13): 19-22. https://doi.org/10.3981/j.issn.1000-7857.2014.13.002

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  This paper studies the damage effect of the tungsten cored armor piercing round (APCR) on the supersonic missile engine cabin. The APCR at a speed of 1000 m/s penetrating into a coming attack supersonic anti-ship missile at a speed of 730 m/s is simulated by the ANSYS/LS-DYNA software, and the rules of damage for the APCR penetrating the engine cabin of the supersonic anti-ship missile at different incidence angles and off-axis distances are acquired. On the premise that the APCR with the same offaxis distance in each condition can penetrate into the engine, the results show that the smaller incidence angle of the condition, the bigger remaining mass after the APCR penetrates into the engine, but the smaller residual velocity. On the premise that the APCR with the same incidence angle in each condition can penetrate into the engine, the results show that the smaller off-axis distance of the condition, the bigger remaining mass, residual velocity and kinetic energy after the APCR penetrates into the engine. When the residual kinetic energy of the APCR is taken as the standard for the damage ability, in general, under the condition that the APCR can penetrate into the engine, the smaller off- axis distance and incidence angle are, the better damage effect after the APCR penetrates into the engine cabin of supersonic anti-ship missile is.
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  Numerical Simulation of Hydrate Slurry Flow Based on Orthogonal Design

  JIANG Guoye, WANG Xiaoya, SUN Peng

  journal1. 2014, 32(13): 23-27. https://doi.org/10.3981/j.issn.1000-7857.2014.13.003

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  The pressure drop of the hydrate slurry in a pipeline is mainly related to the following factors: The velocity of hydrate slurry, the size of the solid phase and the volume fraction of the hydrate. In order to study the characteristics of hydrate slurry transportation in the vertical pipeline, the three parameters are chosen as the design factors and the pressure drop as the evaluation index in the orthogonal test. The numerical simulation reveals that the velocity of the hydrate slurry has the greatest effect on the pressure drop, while the influence of the solid phase takes in the second place and the volume fraction of the hydrate the least. At last, a more favorable delivery scheme is proposed based on the analysis above.
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  Application of Particle Swarm Optimization Algorithm to Denoising Vibration Signal of Gearbox

  ZHANG Pengtao, LIU Jinhao

  journal1. 2014, 32(13): 28-32. https://doi.org/10.3981/j.issn.1000-7857.2014.13.004

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  Taking the gearbox in wind turbine as an example, this paper introduces a method about denoising the vibration signal of gearbox based on the vibration spectrum analysis and particle swarm optimization algorithm. The particle swarm optimization algorithm can reduce the search space by using one dimension search, and improve the optimization result by simultaneously optimizing the design parameters of Chebyshev band pass filter and Morlet wavelet filter, eventually filtering out the fault vibration signal of the gearbox. Experimental results show that this method can effectively eliminate the external noise in the vibration signal, and that the hybrid algorithm can effectively reduce the search range of particle swarm optimization and improve the optimization result for the relevant parameter optimization of Chebyshev band-pass filter and Morlet wavelet filter. It is applicable to the real-time gearbox fault diagnosis research. Therefore, it has certain value for theoretical research and practical applications. This hybrid algorithm has good optimized performance and the optimization process is fast. The fault features are obvious in the denoised signal, and can be applied to the real-time fault diagnosis of gearbox in the future research.
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  Stiffness Simulation Method of Determining Step Size Using Discrete Element Method

  YAN Min, GUO Zhen

  journal1. 2014, 32(13): 33-35. https://doi.org/10.3981/j.issn.1000-7857.2014.13.005

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  The discrete element method (DEM), with its core of using the so-called central difference method, involves actually iterative calculations. During the DEM calculations, the determinations of a reasonable computation time step and the normal stiffness are very important. The determination of the time step is closely related to the stiffness, the mass and the damping of the granule in question, and to their matching relationship. To decide the stiffness is so far through actual measurements. However, it can be done only in some special conditions and it needs a wealth of experience for the simulation results to be close to the practical results. This paper, based on the theoretical consideration and numerical simulations of a mass-spring system, proposes optional ways to determine the calculation time step and the normal stiffness.
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  Effect of Heterogeneity on Water Producing of Ultra-low Permeability Oil Reservoir：An Experimental Study

  YANG Zhengming, GAO Tianfang, FENG Cheng, WANG Zhi, LIU Xuewei

  journal1. 2014, 32(13): 36-40. https://doi.org/10.3981/j.issn.1000-7857.2014.13.006

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  Ultra-low permeability reservoirs have the characteristic of generally developed micro-fractures which lead to strong heterogeneity. Fractured rock cores are made to simulate different combination modes of natural depletion of ultra-low permeability reservoir in this paper. An experimental method of making fractured cores and using them to simulate nature depletion is established. It is a new method that simulates the production performance of an inhomogeneous reservoir through the rock cores parallel water flooding experiment. The results show that the water cut rising process of the heterogeneity reservoir can be divided into four stages. They are the free water oil production stage, water cut rising stage, high water saturation rising stage, and high water cut stage. The features of the water cut curve are influenced by the average water permeability, permeability ratio and micro-fracture. The water cut rising changes of high permeability reservoir, water layer and layers with developed micro-fractures should be focused on in oil field production.
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  Experimental Study on Oil/Water Flow in Fractures

  LIU Min, REN Xianghai, CHANG Lunjie, XIAO Xiangjiao, CHANG Zhiqiang, WANG Yanqiu

  journal1. 2014, 32(13): 41-45. https://doi.org/10.3981/j.issn.1000-7857.2014.13.007

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  Most carbonate rocks are dual porosity-permeability porous media with both pores and fractures. Currently the mechanisms of oil and water flow in the rock fractures remain unclear, causing many problems concerning numerical simulation and reservoir engineering in this kind of carbonate reservoirs. In this study, pressures and flow rates were measured in fractures with different apertures using water and oil. For the single-phase oil flow in fractures, refined oils with different viscosity were used. The experimental data showed that the oil or water flow in fractures became nonlinear when the pressure gradient was greater than a specific value. However, it might not be sound enough to use Re as the only parameter and criterion to judge the linearity of fluid flow. The critical Re was different in fractures with different apertures. Two different types of nonlinear flow was found in fractures.
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  Numerical Analysis of Borehole Instability Mechanism in Layered Shale Formation Based on FLAC3D

  ZHAO Jingying, DENG Jingen, HUANG Zhen, ZHU Haiyan

  journal1. 2014, 32(13): 46-52. https://doi.org/10.3981/j.issn.1000-7857.2014.13.008

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  The layered shale formation is an extremely troublesome formation of borehole instability, with a significant influence on drilling. This paper studies the effect of joint weak planes in the rock mass and proposes a combined model, which combines both the bedding plane model and the intact rock model to describe the characteristics of the layered formation, especially the characteristics of the bedding plane. The finite difference software FLAC3D is used to establish the numerical model of the layered shale formation and to simulate the drilling process. To compare with the isotropic shale formation, the distributions of the failed area, the borehole displacement and the secondary stress in the layered shale formation are obtained. The failure process of the bedding plane and characteristics of the deformation are well simulated. The difference of the displacements on the two sides of the bedding plane is up to 0.8 mm and the slip displacement is 8.13 times the shift displacement. The results agree with the drilling practice. The slip behavior of the bedding plane is shown to be the central cause of the borehole instability in the layered shale formation. The effect of the geo-stress, the occurrence of the bedding plane, the parameters of the well track and the borehole size on the well deformation in inclined and horizontal layered formations are also simulated.
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  Wellbore Instability Mechanism of Broken Formations and Drilling Fluid Countermeasures in G Block, Gabon

  ZHANG Guangyin, JIN Junbin, XIA Bairu

  journal1. 2014, 32(13): 53-57. https://doi.org/10.3981/j.issn.1000-7857.2014.13.009

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  The block in Gabon is an important exploration and development block of Sinopec overseas. Wellbore instability existed in LPC and ANG formations during drilling operations. Through the analysis of shale core apparent characteristics in broken formations, shale cuttings water immersion test, shale and shale clay mineral analysis, and rolling recycling test, it is shown that the Illite / Smectite mixed layers, Illite clay mineral components and micro-fissures are the material conditions of the instability mechanism of broken formation of the G block Gabon. On the other hand, mud filtrates along fractures and fissures deep into the formation to cause hydration swelling of clay minerals and borehole loss of balance, which is the inherent mechanism leading to the collapse of blocks. Anti-sloughing drilling fluid density stress shielding comprehensive technical measures and drilling fluid system and quality recipes were developed. Field tests were conducted in G-9 and G-10 wells in Gabon. The LPC and ANG formation borehole calipers were reduced to 11.6% and 12.1% , respectively, as compared to the neighboring wells. The wellbore quality has been improved significantly, and good wellbore stability has been achieved.
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  Metabonomics Studies on Plasma and Urine of Patients with Breast Cancer Using NMR Spectroscopy

  CHEN Yin, ZHONG Meizuo, UPUR Halmurat, MAMTIMIN Batur, DENG Wanli, ZHANG Hongliang, WANG Rui

  journal1. 2014, 32(13): 58-63. https://doi.org/10.3981/j.issn.1000-7857.2014.13.010

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  Metabonomics studies on plasma and urine of patients with breast cancer using NMR spectroscopy are to establish metabolic markers correlated with breast cancer to guide clinic diagnosis and provide the new ideas and methods. In this study, a total of 45 patients with breast cancer were enrolled and 50 healthy volunteers as controls. Meanwhile, blood and urine samples from the subjects were collected by the researchers for testing. For each sample, the 1H nuclear magnetic resonance (NMR) based metabonomic analysis was performed, the subsection integral of the free attenuation signal was computed, and the obtained data were analyzed by the orthogonal partial least-squares discriminant analysis (OPLS-DA). The results of the study show that compared with the healthy people, leucine, valine, phenylalanine, tyrosine, alanine, histidine, and glycine are significantly decreased (P<0.05); lipid (LDL), beta glucose，lactic acid, choline, inositol and creatine are significantly reduced (P<0.05); glycoprotein, malonic acid, acetoacetic acid, beta hydroxybutyric acid, and acetone are increased significantly (P<0.05) in the plasma of patients with breast cancer. Moreover, isoleucine, valine, glutamic acid, histidine, dimethylamine, hippuric acid, betaine, taurine, succinic acid, citric acid,creatine, and creatinine are decreased (P<0.05) and Lactic acid increased (P<0.05) in urine of patients with breast cancer. Through this study, metabolic markers correlated with breast cancer using changes of metabonomics in plasma and urine have been established.
Reviews
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  Current Hotspots of International Wheat Research

  ZHANG Yinghua, WANG Zhimin, ZHOU Shunli, WANG Bin, XUE Yingwen, LIU Yunpeng, WANG Chao, XI Wenxing

  journal1. 2014, 32(13): 64-69. https://doi.org/10.3981/j.issn.1000-7857.2014.13.011

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  This review focuses on recent advances in some key areas of wheat production, namely determination of potential yield, utilization of germplasm resources, resistance to abiotic stresses, micronutrient and integrated crop management. The main opinions are as follows: Raising wheat yield in the future may rely mainly on the growth of biomass, based on which the harvest index needs to be maintained or increased as much as possible. Wheat germplasm resources are rich, including a large number of excellent genes, which can be used to improve the resistance to adversity and quality. Global warming threatens food security, thus the adaptability of wheat production to climate change needs to be improved. To improve wheat resistance to adversity, important traits including translocation of reserves, the stay-green ability, non-leaf photosynthetic property and root system configuration should be considered as well as common physiological mechanisms. The biofortification of grain micronutrient can be realized by application of fertilizers, conventional plant breeding and genetic- engineering techniques. Application of integrated wheat management can overcome the multiple limiting factors in wheat production, and high yield and efficiency can be achieved by the synergistic interaction of technologies and elements.
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  Progress in Omic of Plant Responses to Elevated Temperature and Drought Stress

  WU Yongbo, XUE Jianhui, LI Bailian

  journal1. 2014, 32(13): 70-73. https://doi.org/10.3981/j.issn.1000-7857.2014.13.012

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  For the past two decades the system biology based on high throughput analysis has been developed rapidly, as well as the research fields of omics, which include genomics, transcriptomic and proteomic, metabolic techniques. Plants are subjected to different levels of abiotic stresses throughout the life process, which seriously affect their growth and development. The technology of omic is crucial to the study of mechanism of plants response to abiotic stress. Elevated temperature and drought, the two most simultaneously occurring abiotic factors, are the important characteristics of global climate change. This paper reviews the recent advances in omic analyses in plant response to elevated temperature and drought abiotic stresses, as well as the further research perspective in the field, to provide a reference for the future study of plant responses to elevated temperature and drought stresses.
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  Shale Gas Produced Water Contamination and Its Comprehensive Treatment

  WU Qingyun, ZHENG Meng, HU Yunxia

  journal1. 2014, 32(13): 74-83. https://doi.org/10.3981/j.issn.1000-7857.2014.13.013

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  Shale gas is considered a form of clean unconventional natural gas with low carbon footprint and huge reserves, and has increasingly attracted attention as a new energy resource around the world. In recent years, the hydraulic fracturing technique has become very common in wells for shale gas drilling, which consumes tons of fresh water and produces a large amount of high salinity water. Managing the produced water and promoting cost-effective water reuse is a major challenge for maintaining the profitability of shale gas extraction while protecting public health and the environment. In this article, the hydraulic fracturing process is reviewed and the composition of shale gas produced water is analyzed. Then, the promising techniques of treating wastewater, including mechanical vapor compression, membrane distillation, reverse osmosis, forward osmosis, electrocoagulation, and ozone catalytic oxidation, are reviewed respectively, followed by a discussion on their advantages and challenges. It is concluded that the hybrid system combing more than one technique to treat wastewater could be a promising approach to real application.