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Experimental research on grouser traction of deep-sea mining machine

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Applied Mathematics and Mechanics(English Edition) 2015年第9期36卷 1243-1252页

作者： Wenbo MA Qiuhua RAO kang feng feng XU School of Civil Engineering Central South University

The traction characteristics of the grouser, cutting the simulative soil of deepsea sediment, with different tooth widths, tooth heights, and ground pressures are studied with traction characteristic test apparatus. A traction-displacement model is obtained by combining the analysis of the cutting mechanism. The results show that the tractiondisplacement curves of grousers with different tooth widths, tooth heights, and ground pressures have the same changing trend, which matches the Wong traction model. Their sensitivity coefficient and shear modulus are slightly fluctuated. Therefore, the average values can be used as the traction model parameters. The maximum traction of the grouser with a two-side edge and a 10 mm tooth width increment changing with the tooth height and ground pressure can be determined according to the grousers with different tooth widths. By combining the traction model parameters, the traction-displacement curve of the grouser with a certain group values of tooth width, tooth height, and ground pressure can be predicted. Therefore, the slip of the mining machine can be prevented to improve the mining efficiency.

关键词： deep-sea sediment simulative soil traction test deep-sea mining machine,grouser traction model

Experiment and Numerical Simulation of Free Water Jet by a Central-body Nozzle

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 797-804页

作者： YANG Minguan ZHANG feng kang Can GAO Bo School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

The recent research about cavitation jet mainly focuses on the organ-pipe nozzle and triangular nozzle. The research content mainly includes the optimized design about the structure of nozzles, the observation and flow analysis about the cavitation jet in the water, and the theory of rock attacked by the cavitation jet, while the energy characteristic of the free jet is not studied yet. In China, the research about the central-body nozzle is almost empty. For the purpose of studying the energy characteristic and the structure of free water jet discharged from central-body nozzle, an experiment with phase Doppler particle anemometry（PDPA） technology is carried out to measure the free water jet flow, which is produced by a central-body nozzle under the jet pressure of 15 MPa. While five sections with different axial distances from the nozzle outlet are selected for data process and analysis, the axial and radial velocity and the droplets of the particle size are studied. Meanwhile, numerical calculation of corresponding flow field is conducted by using volume of fluid（VOF） multiphase model, and the jet flow feature is discussed. The experimental and calculating results show that the axial velocity of high speed jet flow dissipates slowly in the air, and the core area and diffused area are discovered. The diameter of droplet in the core area is small, and jet energy is concentrated, while in the diffusion area, water is mingled with ambient air and radial velocity is relatively large. Obvious low-pressure area exists behind the central body and potential cavitation may occur in that area. The proposed research reveals the energy characteristic of free jet discharged from central-body nozzle, provides the theoretical basis for preestimating erosion feature of the central-body nozzle and also the theoretical foundation for revealing the mechanism of erosion.

关键词： central-body nozzle free water jet phase Doppler particle anemometry(PDPA) energy characteristic VOF model

Multiphase Flow and Wear in the Cutting Head of Ultra-high Pressure Abrasive Water Jet

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 729-734页

作者： YANG Minguan WANG Yuli kang Can YU feng School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 China

Abrasive water jet cutting technology is widely applied in the materials processing today and attracts great attention from scholars, but many phenomena concerned are not well understood, especially in the internal jet flow of the cutting head at the condition of ultra-high pressure. The multiphase flow in the cutting head is numerically simulated to study the abrasive motion mechanism and wear inside the cutting head at the pressure beyond 300 MPa. Visible predictions of the particles trajectories and wear rate in the cutting head are presented. The influences of the abrasive physical properties, size of the jewel orifice and the operating pressure on the trajectories are discussed. Based on the simulation, a wear experiment is carried out under the corresponding pressures. The simulation and experimental results show that the flow in the mixing chamber is composed of the jet core zone and the disturbance zone, both affect the particles trajectories. The mixing efficiency drops with the increase of the abrasive granularity. The abrasive density determines the response of particles to the effects of different flow zones, the abrasive with medium density gives the best general performance. Increasing the operating pressure or using the jewel with a smaller orifice improves the coherency of p articles trajectories but increases the wear rate of the jewel holder at the same time. Walls of the jewel holder, the entrance of the mixing chamber and the convergence part of the mixing tube are subject to wear out. The computational and experimental results give a qualitative consistency which proves that this numerical method can provide a reliable and visible cognition of the flow characteristics of ultra-high pressure abrasive water jet. The investigation is benefit for improving the machining properties of water jet cutting systems and the optimization design of the cutting head.

关键词： abrasive water jet cutting head multiphase flow wear

Three-Dimensional Thermo-mechanical Coupled FEM Simulation for Hot Continuous Rolling of Large-Diameter Mandrel Bar

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Journal of Materials Science & Technology 2003年第Z1期19卷 228-230页

作者： Huiping HONG Yonglin kang Changtao feng Xiqiang CHEN School of Materials Science and Engineering University of Sicence and Technology Beijing Beijing 100083 China Baoshan Iron and Stddl Co. Ltd.Shanghai 201900China School of Materials Science and Engineering University of Sicence and Technology Beijing Beijing 100083 China Baoshan Iron and Stddl Co. Ltd.Shanghai 201900China School of Materials Science and Engineering University of Sicence and Technology Beijing Beijing 100083 China Baoshan Iron and Stddl Co. Ltd.Shanghai 201900China School of Materials Science and Engineering University of Sicence and Technology Beijing Beijing 100083 China Baoshan Iron and Stddl Co. Ltd.Shanghai 201900China

Based on the important boundary conditions of rolling simulation including friction, heat conduction and interactionsof the workpiece and rolls, the hot continuous rolling processes of large-diameter mandrel round bar (200 mm indiameter) in 6VH-stand hot tandem mill are successfully simulated by three-dimensional coupled thermomechanicalelastoplastic finite element method (FEM). The distributions of stress, strain, temperature and the rolling force andtorque for the two-pass and four-pass continuous rolling are calculated respectively. Thus, the two and four-passroll schedules are verified, respectively. The simulation results show that it is safe to produce 200 mm round barby the two-pass (oval pass and round pass) continuous rolling on the existing equipment compared to the four-passcontinuous rolling. There are concave surfaces and increased widths occurring at the end of rolled billet due touneven deformations between the outside and inside of the workpiece as well as the free spreading close to the rollgap of the final pass.

关键词： Mandrel, Round bar, Hot continuous rolling, Thermomechanical coupled analysis,Finite element method.

Neural stem cell activation and glial proliferation in the hippocampal CA3 region of posttraumatic epileptic rats

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Neural Regeneration Research 2011年第16期6卷 1232-1237页

作者： Yuanxiang Lin Kun Lin Dezhi kang feng Wang Department of Neurosurgery First Affiliated Hospital of Fujian Medical University Fuzhou 350005 Fujian Province China

The present study observed the dynamic expression of CD133, nuclear factor-κB and glial fibrUlary acidic protein in the hippocampal CA3 area of the experimental posttraumatic epilepsy rats to investigate whether gliosis occurs after posttraumatic epilepsy. CD133 and nuclear factor-κB expression was increased at 1 day after posttraumatic epilepsy, peaked at 7 days, and gradually decreased up to 14 days, as seen by double-irnmunohistochemical staining. Glial fibrillary acidic protein/nuclear factor-EB double-labeled cells increased with time and peaked at 14 days after posttraumatic epilepsy. Results show that activation of hippocampal neural stem cells and glial proliferation after posttraumatic epilepsy-induced oxidative stress increases hippocampal glial cell density.

关键词： posttraumatic epilepsy neural stem cell glial cell CD133 nuclear factor-κB glialfibrillary acidic protein neural regeneration

Structural Characteristics and Molecular Mechanism of Hepatitis B Virus Reverse Transcriptase

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Virologica Sinica 2009年第6期24卷 509-517页

作者： Hui feng kang-hong HU State Key Laboratory of Virology Wuhan Institute of Virology Chinese Academy of Sciences Wuhan 430071China

Hepatitis B virus (HBV), a typical member of the Hepadnaviridae family, is responsible for infections that cause B-type hepatitis which leads to severe public health problems around the world. The small enveloped DNA-containing virus replicates via reverse transcription, and this unique process is accomplished by the virally encoded reverse transcriptase (RT). This multi-functional protein plays a vital role in the viral life cycle. Here, we provide a summary of current knowledge regarding the structural characteristics and molecular mechanisms of HBV RT. Improved understanding of these processes is of both theoretical and practical significance for fundamental studies of HBV and drug discovery.

关键词： Hepadnavirus Hepatitis B virus (HBV) Reverse transcriptase

Evaluation of grapevine sucker segmentation algorithms for precision targeted spray

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International Journal of Agricultural and Biological Engineering 2015年第4期8卷 77-85,I0002页

作者： Xu Shasha Li Wenbin kang feng Zheng Yongjun Lan Yubin School of Technology Beijing Forestry UniversityBeijing 100083China College of Engineering China Agricultural UniversityBeijing 100083China College of Engineering South China Agricultural UniversityGuangzhou 510642China

Chemical sucker control has been proven to be an effective substitute for manual and mechanical *** and location of suckers is the key technology of precision targeted spray which can reduce spray volume than current spray *** goal of this research was to develop a quick and effective segmentation algorithm of sucker images for real-time mobile targeted spray by evaluating and comparing seven segmentation algorithms categorized into segmentation based on color feature(ExG,ExGExR,and CIVE),K-means clustering segmentation in CIE L*a*b*space(K-Lab),and mean shift clustering segmentation based on color feature(ExG-MS,ExGExR-MS,and CIVE-MS)from time consuming and *** results indicated that ExGExR and CIVE took shorter time than other algorithms,and were more suitable for real-time *** further evaluating segmentation accuracy,ExGExR,CIVE,and mean shift algorithms were acceptable to kill *** ExGExR was the best algorithm for sucker segmentation in consideration of time consuming and accuracy,next came CIVE.

关键词： grapevine suckers image segmentation color feature K-means mean shift

Degradation of a fullerene end-capped polycaprolactone by lipase AK

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Chinese Science Bulletin 2010年第29期55卷 3279-3282页

作者： PENG QiYun kang feng LI Juan YANG XinLin School of Life Science and Technology Beijing Institute of Technology Beijing 100081 China

Using titrimetric method,enzymatic behavior of lipase AK against fullerene end-capped polycaprolactone(C60-PCL) was studied for the first time,compared with polycaprolactone(PCL).The results showed that degradation of both C60-PCL and PCL by lipase followed Mechaelis-Menten equation,with the degradation parameters of PCL and C60-PCL were 0.75 mg mL-1 and 0.16 mg mL-1 for Km,and 0.90 mL h-1 and 0.43 mL h-1 for Vmax,respectively.C60-PCL had a slower degradation rate than PCL under the same *** data indicated that the introduction of fullerene enabled PCL hard to be degraded by lipase.

关键词：聚己内酯脂肪酶富勒烯降解酶封端 PCL C60 米氏方程

Influence of Residual Stress on the Dimensional Instability of 7075 Aluminum Cone-Shaped Shells

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稀有金属材料与工程 2009年第A3期38卷 91-94页

作者： Wang Qiucheng Zhao Zude Wang Yisi Xing Hongyan kang feng MOE Key Lab of Mechanical Manufacture ＆Automation Zhejiang University of Technology Hangzhou 310032 China No.59 institute of China Ordnance Industry Chongqing 400039 China

This paper dealt with the influence of residual stress on the dimensional instability of 7075 aluminum cone-shaped shells. Finite element method was introduced to calculate residual stress distributions in 7075 aluminum cone-shaped shells during conventional heat treatment (CHT) and deep cryogenic treatment (DCT). An example was given to demonstrate effects of deep cryogenic treatment (DCT) and conventional heat treatment (CHT) on dimensional instability. It is concluded that initial residual stresses have detrimental influence on the dimensional instability of 7075 aluminum cone-shaped shells.

关键词：残余应力铝合金有限元分析物理性能