A new thermal ring-opening polymerization technique for 1, 1, 3, 3-tetra-ph enyl-1, 3-disilacyclobutane （TPDC） based on the use of metal nanoparticles produced by pulsed laser ablation was investigated. This method ...A new thermal ring-opening polymerization technique for 1, 1, 3, 3-tetra-ph enyl-1, 3-disilacyclobutane （TPDC） based on the use of metal nanoparticles produced by pulsed laser ablation was investigated. This method facilitates the synthesis of polydiphenysilylenemethyle （PDPhSM） thin film, which is difficult to make by conventional methods because of its insolubility and high melting point. TPDC was first evaporated on silicon substrates and then exposed to metal nanoparticles deposition by pulsed laser ablation prior to heat treatment.The TPDC films with metal nanoparticles were heated in an electric furnace in air atmosphere to induce ring-opening polymerization of TPDC. The film thicknesses before and after polymerization were measured by a stylus profilometer. Since the polymerization process competes with re-evaporation of TPDC during the heating, the thickness ratio of the polymer to the monomer was defined as the polymerization efficiency, which depends greatly on the technology conditions. Therefore, a well trained radial base function neural network model was constructed to approach the complex nonlinear relationship. Moreover, a particle swarm algorithm was firstly introduced to search for an optimum technology directly from RBF neural network model. This ensures that the fabrication of thin film with appropriate properties using pulsed laser ablation requires no in-depth understanding of the entire behavior of the technology conditions.展开更多
Slow strain rate testing （SSRT） was employed to study the stress corrosion cracking （SCC） behavior of ZE41 magnesium alloy in 0.01 M NaCl solution. Smooth tensile specimens with different thicknesses were strained...Slow strain rate testing （SSRT） was employed to study the stress corrosion cracking （SCC） behavior of ZE41 magnesium alloy in 0.01 M NaCl solution. Smooth tensile specimens with different thicknesses were strained dynamically in both longitudinal and transverse direction under permanent immersions at a strain rate of 10-6 s-1. It is found that ZE41 magnesium alloy is susceptible to SCC in 0.01 M NaCl solution. The SCC susceptibility of the thinner specimen is lower than that of the thicker specimen. Also, the longitudinal specimens are slightly more susceptible to SCC than the transverse specimens. The SCC mechanism of magnesium alloy is attributed to the combination of anodic dissolution with hydrogen embrittlement.展开更多
The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid （DMSO） organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and...The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid （DMSO） organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.展开更多
Process technology of multiple cylindrical micro-pins by wire-electrical discharge machining （wire-EDM） and electrochemical etching was presented. A row of rectangular micro-columns were machined by wire-EDM and the...Process technology of multiple cylindrical micro-pins by wire-electrical discharge machining （wire-EDM） and electrochemical etching was presented. A row of rectangular micro-columns were machined by wire-EDM and then machined into cylindrical shape by electrochemical etching. However, the shape of the multiple electrodes and the consistent sizes of the electrodes row are not easy to be controlled. In the electrochemical process, the shape of the cathode electrode determines the current density distribution on the anode and so the forming of multiple electrodes. This paper proposes a finite element method （FEM） to accurately optimize the electrode profile. The microelectrodes row with uniformity diameters with size from hundreds micrometers to several decades could be fabricated, and mathematical model controlling the shape and diameter of multiple microelectrodes was provided. Furthermore, a good agreement between experimental and theoretical results was confirmed.展开更多
Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic c...Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.展开更多
In order to reduce cucumber harvesting cost and improve economic benefits,a cucumber harvesting robot was developed.The cucumber harvesting robot consists of a vehicle,a 4-DOF articulated manipulator,an end-effector,a...In order to reduce cucumber harvesting cost and improve economic benefits,a cucumber harvesting robot was developed.The cucumber harvesting robot consists of a vehicle,a 4-DOF articulated manipulator,an end-effector,an upper monitor,a vision system and four DC servo drive systems.The Kinematics of the cucumber harvesting robot manipulator was constructed using D-H coordinate frame model.And the inverse kinematics which provides a foundation for trajectory planning has been solved with inverse transform technique.The cycloidal motion,which has properties of continuity and zero velocity and acceleration at the ports of the bounded interval,was adopted as a feasible approach to plan trajectory in joint space of the cucumber harvesting robot manipulator.Moreover,hardware and software based on CAN-bus communication between the upper monitor and the joint controllers have been designed.Experimental results show that the upper monitor communicates with the four joint controllers efficiently by CAN-bus,and the integrated errors of four joint angles do not exceed four degrees.Probable factors resulting in the errors were analyzed and the corresponding solutions for improving precision are proposed.展开更多
As the representation of new concept agricultural machinery,agricultural robots possess great advantages of improving agricultural productivity,enhancing production environment and solving the problem of labor shortag...As the representation of new concept agricultural machinery,agricultural robots possess great advantages of improving agricultural productivity,enhancing production environment and solving the problem of labor shortage.Therefore,the strategy for application of agricultural robots and precision agriculture to improve the intelligence and information level of agriculture is the inevitable trend for China’s agriculture in the twentieth century.Based on the developmental status of agricultural robots in China,the agricultural robots are categorized and the performances,structures and characteristics of various agricultural robots such as vegetable grafting robots,transplanting robots,spraying robots,mowing robots,harvesting robots,grading and detecting robots are amply introduced.It can be seen that vegetable grafting robots,spraying robots,harvesting robots,grading and detecting robots have already been put into production while others are still at experimental stage.At present,there are several problems such as low popularization,great limitations,high cost and low intelligence,which greatly restrict the development of agricultural robots in China.Thus,open agricultural robot system with good expansibility,generality and flexibility should be developed and adopted to decrease its cost and shorten developing cycle.The mechanical structure of robots should also be designed as simply as possible.Finally,multi-robot system would become another important development direction of agricultural robots in the future.展开更多
基金Funded by the Zhejiang Provincial Natural Science Foundation of China(No.R405031)Jiaxing Science Planning Project(2009 2007)the Educa-tion Department of Zhejiang Province (No.20051441)
文摘A new thermal ring-opening polymerization technique for 1, 1, 3, 3-tetra-ph enyl-1, 3-disilacyclobutane （TPDC） based on the use of metal nanoparticles produced by pulsed laser ablation was investigated. This method facilitates the synthesis of polydiphenysilylenemethyle （PDPhSM） thin film, which is difficult to make by conventional methods because of its insolubility and high melting point. TPDC was first evaporated on silicon substrates and then exposed to metal nanoparticles deposition by pulsed laser ablation prior to heat treatment.The TPDC films with metal nanoparticles were heated in an electric furnace in air atmosphere to induce ring-opening polymerization of TPDC. The film thicknesses before and after polymerization were measured by a stylus profilometer. Since the polymerization process competes with re-evaporation of TPDC during the heating, the thickness ratio of the polymer to the monomer was defined as the polymerization efficiency, which depends greatly on the technology conditions. Therefore, a well trained radial base function neural network model was constructed to approach the complex nonlinear relationship. Moreover, a particle swarm algorithm was firstly introduced to search for an optimum technology directly from RBF neural network model. This ensures that the fabrication of thin film with appropriate properties using pulsed laser ablation requires no in-depth understanding of the entire behavior of the technology conditions.
基金Funded by the National Natural Science Foundation of China (No.50771093)
文摘Slow strain rate testing （SSRT） was employed to study the stress corrosion cracking （SCC） behavior of ZE41 magnesium alloy in 0.01 M NaCl solution. Smooth tensile specimens with different thicknesses were strained dynamically in both longitudinal and transverse direction under permanent immersions at a strain rate of 10-6 s-1. It is found that ZE41 magnesium alloy is susceptible to SCC in 0.01 M NaCl solution. The SCC susceptibility of the thinner specimen is lower than that of the thicker specimen. Also, the longitudinal specimens are slightly more susceptible to SCC than the transverse specimens. The SCC mechanism of magnesium alloy is attributed to the combination of anodic dissolution with hydrogen embrittlement.
文摘The effectiveness of the corrosion protection of Nafion/Dimethysulfoxid （DMSO） organic coatings for AM50 magnesium alloy prepared by simple immersion and heat treatment was investigated. Its corrosion resistance and morphologies of the Nafion/DMSO organic coatings were studied by electrochemical corrosion testing and optical microscopy. The results show that Nafion/DMSO organic coatings can improve the corrosion resistance of AM50 magnesium alloy effectively. Also, the corrosion resistance increases with the surface density of the organic coatings.
基金the financial support from China Aviation Science Foundation (04H52055).
文摘Process technology of multiple cylindrical micro-pins by wire-electrical discharge machining （wire-EDM） and electrochemical etching was presented. A row of rectangular micro-columns were machined by wire-EDM and then machined into cylindrical shape by electrochemical etching. However, the shape of the multiple electrodes and the consistent sizes of the electrodes row are not easy to be controlled. In the electrochemical process, the shape of the cathode electrode determines the current density distribution on the anode and so the forming of multiple electrodes. This paper proposes a finite element method （FEM） to accurately optimize the electrode profile. The microelectrodes row with uniformity diameters with size from hundreds micrometers to several decades could be fabricated, and mathematical model controlling the shape and diameter of multiple microelectrodes was provided. Furthermore, a good agreement between experimental and theoretical results was confirmed.
文摘Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.
基金the Natural Science Foundation of China(50575206)the National High-Tech Research and Development(863)Program of China(2007AA04Z222)。
文摘In order to reduce cucumber harvesting cost and improve economic benefits,a cucumber harvesting robot was developed.The cucumber harvesting robot consists of a vehicle,a 4-DOF articulated manipulator,an end-effector,an upper monitor,a vision system and four DC servo drive systems.The Kinematics of the cucumber harvesting robot manipulator was constructed using D-H coordinate frame model.And the inverse kinematics which provides a foundation for trajectory planning has been solved with inverse transform technique.The cycloidal motion,which has properties of continuity and zero velocity and acceleration at the ports of the bounded interval,was adopted as a feasible approach to plan trajectory in joint space of the cucumber harvesting robot manipulator.Moreover,hardware and software based on CAN-bus communication between the upper monitor and the joint controllers have been designed.Experimental results show that the upper monitor communicates with the four joint controllers efficiently by CAN-bus,and the integrated errors of four joint angles do not exceed four degrees.Probable factors resulting in the errors were analyzed and the corresponding solutions for improving precision are proposed.
基金This work is financially supported by the Natural Science Foundation of China(50575206)the National High-Tech Research and Development(863)Program of China(2007AA04Z222).
文摘As the representation of new concept agricultural machinery,agricultural robots possess great advantages of improving agricultural productivity,enhancing production environment and solving the problem of labor shortage.Therefore,the strategy for application of agricultural robots and precision agriculture to improve the intelligence and information level of agriculture is the inevitable trend for China’s agriculture in the twentieth century.Based on the developmental status of agricultural robots in China,the agricultural robots are categorized and the performances,structures and characteristics of various agricultural robots such as vegetable grafting robots,transplanting robots,spraying robots,mowing robots,harvesting robots,grading and detecting robots are amply introduced.It can be seen that vegetable grafting robots,spraying robots,harvesting robots,grading and detecting robots have already been put into production while others are still at experimental stage.At present,there are several problems such as low popularization,great limitations,high cost and low intelligence,which greatly restrict the development of agricultural robots in China.Thus,open agricultural robot system with good expansibility,generality and flexibility should be developed and adopted to decrease its cost and shorten developing cycle.The mechanical structure of robots should also be designed as simply as possible.Finally,multi-robot system would become another important development direction of agricultural robots in the future.
