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Enhancement of Mechanical Properties of Natural Rubber with Maleic Anhydride Grafted Liquid Polybutadiene Functionalized Graphene Oxide

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Chinese Journal of Polymer Science 2015年第7期33卷 1058-1068页

作者： Long-mei Wu 廖双泉 Sheng-jun Zhang Xiao-ying Bai Xue Hou College of Agriculture Hainan University College of Materials and Chemical Engineering Hainan University

An effective procedure has been developed to synthesize the functionalized graphene oxide grafted by maleic anhydride grafted liquid polybutadiene（MLPB-GO）. Fourier transform spectroscopy and X-ray photoelectron spectroscopy indicate the successful functionalization of GO. The NR/MLPB-GO composites were then prepared by the co-coagulation process. The results show that the mechanical properties of NR/MLPB-GO composites are obviously superior to those of NR/GO composites and neat NR. Compared with neat NR, the tensile strength, modulus at 300% strain and tear strength of NR composite containing 2.12 phr MLPB-GO are significantly increased by 40.5%, 109.1% and 85.0%, respectively. Dynamic mechanical analysis results show that 84% increase in storage modulus and 2.9 K enhancement in the glass transition temperature of the composite have been achieved with the incorporation of 2.12 phr MLPB-GO into NR. The good dispersion of GO and the strong interface interaction in the composites are responsible for the unprecedented reinforcing efficiency of MLPB-GO towards NR.

关键词： Enhancement Maleic anhydride-grafted liquid polybutadiene Graphene oxide Composites Mechanical properties

Direct electrochemical reduction of solid vanadium oxide to metal vanadium at low temperature in molten CaCl_2-NaCl

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 499-505页

作者： Zhuo-fei Cai Zhi-mei Zhang Zhan-cheng Guo Hui-qing Tang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China

V205 sintered pellets and graphite rods were employed as the cathode and the anode, respectively; a molten CaC12-NaCI salt was used as the electrolyte. Then, V205 was directly reduced to metal vanadium by the Fray-Farthing-Chen （FFC） method at 873 K to realize low-temperature electrolysis. Two typical experimental conditions, electrolysis time and voltage, were taken into account to investigate the current efficiency and remaining oxygen content in electrolyzed products. The composition and microstmcture of the products were charac- terized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. SEM observations show that a higher voltage （1.8-3.4 V） and a longer electrolysis time （2-5 h） can improve the product quality separately, that is, a lower remaining oxygen content and a more uniform microstructure. The products with an oxygen content of 0.205wt% are successfully obtained below 3.4 V for 10 h. However, the current effi- ciency is low, and further work is required.

关键词： vanadium metallurgy vanadium pentoxide direct reduction electrolysis

Metallacycle Expansion and Annulation:Access to Tetrazolo-Fused Osmacycles by Reaction of Cyclic Osmium Carbyne with Sodium Azide

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Chinese Journal of Chemistry 2021年第12期39卷 3435-3442页

作者： Hongjian Wang Yu-mei Lin Siyuan Chen Yonghong Ruan Haiping Xia State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Shenzhen Grubbs Institute Department of ChemistrySouthern University of Science and TechnologyShenzhenGuangdong 518055China

The reaction of a cyclic osmacarbyne complex with sodium azide led to the formation of a ring expansion-annulation product,a unique tetrazole annulated polycyclic *** reaction proceeds by insertion of a nitrogen atom into the metal carbon triple bond and the second azide participating in the[2+3]*** successful isolation and characterization of metalla-azirine complex and metallapyridinium derivative strongly validated the mechanism for the formation of the title *** work demonstrates a new strategy to enrich the varieties of aza-metallacyclic species.

关键词： Metallacycles Osmiurncarbyne Ring expansion Annulation Aza-heterocycle

Trajectory optimization of multiple quad-rotor UAVs in collaborative assembling task

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Chinese Journal of Aeronautics 2016年第1期29卷 184-201页

作者： Chen Yongbo Yu Jianqiao mei Yuesong Zhang Siyu Ai Xiaolin Jia Zhenyue School of Aerospace Engineering Beijing Institute of Technology

A hierarchic optimization strategy based on the offline path planning process and online trajectory planning process is presented to solve the trajectory optimization problem of multiple quad-rotor unmanned aerial vehicles in the collaborative assembling task. Firstly, the path planning process is solved by a novel parallel intelligent optimization algorithm, the central force optimization-genetic algorithm （CFO-GA）, which combines the central force optimization （CFO） algorithm with the genetic algorithm （GA）. Because of the immaturity of the CFO, the convergence analysis of the CFO is completed by the stability theory of the linear time-variant discrete-time sys- tems. The results show that the parallel CFO-GA algorithm converges faster than the parallel CFO and the central force optimization-sequential quadratic programming （CFO-SQP） algorithm. Then, the trajectory planning problem is established based on the path planning results. In order to limit the range of the attitude angle and guarantee the fight stability, the optimized object is changed from the ordinary six-degree-of-freedom rigid-body dynamic model to the dynamic model with an inner-loop attitude controller. The results show that the trajectory planning process can be solved by the mature SQP algorithm easily. Finally, the discussion and analysis of the real-time per- formance of the hierarchic optimization strategy are presented around the group number of the wav^oints and the eoual interval time.

关键词： Hierarchic optimizationstrategy Parallel CFO-GA algorithm Path planning Six,degree-of-freedom rigid-body dynamic model Trajectory optimization Trajectory planning

Surface reconstruction from unorganized point clouds based on edge growing

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Advances in Manufacturing 2019年第3期7卷 343-352页

作者： Xu-Jia Qin Zhong-Tian Hu Hong-Bo Zheng mei-Yu Zhang College of Computer Science and Technology Zhejiang University of TechnologyHangzhou 310023People's Republic of China Key Laboratory of Visual Media Intelligent Processing Technology of Zhejiang Province Hangzhou 310023People's Republic of China

Owing to unorganized point cloud data,unexpected triangles,such as holes and slits,may be generated during mesh surface *** solve this problem,a mesh surface reconstruction method based on edge growing from unorganized point clouds is *** method first constructs an octree structure for unorganized point cloud data,and determines the k-nearest neighbor for each ***,the method searches for flat areas in the point clouds to be used as the initial mesh edge growth regions,to avoid incorrect reconstruction of the mesh surface owing to the growth of initial sharp ***,the optimal mesh surface is obtained by controlling the mesh edge growing based on compulsive restriction and comprehensive optimization *** experimental results of mesh surface reconstruction show that the method is feasible and shows high reconstruction performance without introducing holes or slits in the reconstructed mesh surface.

关键词： Mesh surface reconstruction Point clouds Edge growing Octree

Chloride content and pH value in the pore solution of concrete under carbonation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第1期14卷 71-78页

作者： Xiao-mei WAN Folker H. WITTMANN Tie-jun ZHAO Hong FAN Aedificat Institute Freiburg Freiburg D-79100 Germany School of Civil Engineering Qingdao Technological University

Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive pa- rameters for initiation and rate of corrosion. The pore solution of cement mortar and hardened cement paste has been expressed from the pore space by high pressure in the investigation. The influence of the water-cement ratio, age, and addition of chloride to the fresh mix on chloride content in the pore solution has been determined by ion chromatography. At the same time the pH value of the pore solution has been determined. The dissolved chloride content decreases with increase in the water-cement ratio. The amount of bound chloride increases with time, but it decreases with decreasing content of dissolved chloride in the pore solution. A significant influence of carbonation on the dissolved chloride content of the pore solution has been observed. With complete carbonation, the dissolved chloride content in cement mortar and hardened cement paste increases by a factor between 2 and 12. The bound chloride decreases by 27%--54%. As expected, the pH value decreases from around 13.2 to as low as 8.0 due to car- bonation. It can be concluded that carbonation not only lowers the pH value but liberates bound chloride. This is one obvious reason why the combined action of chloride penetration and carbonation accelerates steel corrosion and shortens the service life of reinforced concrete structures.

关键词： Chloride Pore solution Carbonation pH value

Energy-efficient Bio-inspired Gait Planning and Control for Biped Robot Based on Human Locomotion Analysis

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Journal of Bionic Engineering 2016年第2期13卷 271-282页

作者： Hongbo Zhu Minzhou Luo Tao mei Jianghai Zhao Tao Li Fayong Guo Department of Automation School of Information Science and Technology University of Science and Technology of China Hefei 230022 China Institute of Advanced Manufacturing Technology Hefei Institutes of Physical Science Chinese Academy of Sciences Changzhou 213164 China

In this paper an experiment of human locomotion was carried out using a motion capture system to extract the human gait features. The modifiable key gait parameters affecting the dominant performance of biped robot walking were obtained from the extracted human gait features. Based on the modifiable key gait parameters and the Allowable Zero Moment Point （ZMP） Variation Region （AZR）, we proposed an effective Bio-inspired Gait Planning （BGP） and control scheme for biped robot to- wards a given travel distance D. First, we construct an on-line Bio-inspired Gait Synthesis algorithm （BGSN） to generate a complete walking gait motion using the modifiable key gait parameters. Second, a Bio-inspired Gait Parameters Optimization algorithm （BGPO） is established to minimize the energy consumption of all actuators and guarantee biped robot walking with certain walking stability margin. Third, the necessary controllers for biped robot were introduced in briefly. Simulation and experiment results demonstrated the effectiveness of the proposed method, and the gait control system was implemented on DRC-XT humanoid robot.

关键词： motion capture Allowable Zero Moment Point (ZMP) Variation Region (AZR) Bio-inspired Gait Planning (BGP) humanoid robot

Gene cloning and sequence analysis of the cold-adapted chaperones DnaK and DnaJ from deep-sea psychrotrophic bacterium Pseudoalteromonas sp. SM9913

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Acta Oceanologica Sinica 2007年第6期26卷 91-100页

作者： ZHAO Dianli CHEN Xiulan HE Hailun SHI mei ZHANG Yuzhong State Key Laboratory of Microbial Technology Marine Biotechnology Research Center Shandong University Jinan 250100 China

Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.

关键词： cold-adapted chaperone DnaJ DnaK deep-sea Pseudoalteromonas sp. SM9913 gene cloning sequence analysis

Single and joint stress of acetochlor and Pb on three agricultural crops in northeast China

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Journal of Environmental Sciences 2007年第6期19卷 719-724页

作者： CHAO Lei ZHOU Qi-xing CHEN SU CUI Shuang WANG mei-e Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China The Graduate School of Chinese Academy of Sciences Beijing 100039 China College of Environmental Science and Engineering Nankai University lianjin 300071 China

In order to evaluate ecological risk of agrochemicals in agricultural environment, single and joint toxic effects of an important herbicide and a typical heavy metal on root elongation of crops were investigated. Seeds of the three crops including wheat （Triticum aestivum）, Chinese cabbage （Brassica pekimensis） and soybean （Glycine max） as the main crops in northeast China were exposed to acetochior as a herbicide and lead （Pb） as a heavy metal using the pot-culture method, and meadow brown soil as one of the main soils distributed in northeast China was applied in the investigation. The results indicated that the interactive effects of the two pollutants on root elongation of the three crops were very complicated although they had markedly significant （P〈0.01） linear interrelationships based on the regression analyses. When the concentration of added Pb^2＋ reached 200 mg/kg, acetochlor and Pb had an antagonistic effect on the inhibition of root elongation of the three crops. However, acetochlor and Pb had significantly （P〈0.05） synergic effects on the inhibition of root elongation when concentration of added Pb^2＋ was up to 1000 mg/kg. At the low concentration of added Pb, joint toxicity of acetochlor and Pb was more dependent on the concentration of Pb. Among the three crops, wheat was the most sensitive to the toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.

关键词： acetochlor Pb ecotoxicology joint effect Chinese cabbage (Brassica pekimensis) soybean (Glycine max) wheat (Triticum aestivum)