A new adaptive cruise control (ACC) method based on the desired safety headway distance is investigated for improving the vehicle traffic safety at high speed by regulating the additional throttle opening and braking ...A new adaptive cruise control (ACC) method based on the desired safety headway distance is investigated for improving the vehicle traffic safety at high speed by regulating the additional throttle opening and braking torque of driving wheels only. The selection of headway distance sensors, the determination of desired safety headway distance and desired deceleration are elaborated. The ACC flowchart and simulation, as well as signal misinformation and its resolutions are described. The simulation proves that the new ACC method is simpler and feasible. The new method is easily integrated ACC with ABS/ASR to form an organic ABS/ASR/ACC system.展开更多
In order to develop green good, reduce the use of chemical fertilizer and pesticide, realize "double reduction" and synergism, improve safety and quality of products, protect the ecological environment and promote t...In order to develop green good, reduce the use of chemical fertilizer and pesticide, realize "double reduction" and synergism, improve safety and quality of products, protect the ecological environment and promote the healthy and steady development of strawberry industry, the goals and key technology of fertilizer-pesticide "double reduction" and synergism for greenhouse strawberry are summed up in this paper targeting at the current situation of strawberry production and combined with the new technology achievements at home and abroad. The key technology includes six items: healthy seedling cultivating technique, soil improvement and continuous cropping obstacle treatment technique, agricultural ecological prevention tech- nique, physicochemical trap of pest control technique, biological control technique and low residual risk chemical control technique.展开更多
人头费:只见增,不见减目前有一些机关,行政编制满了,便弄事业编制,事业编制满了,便招临时人员,逐渐形成了“一个人的活两个人干,一个人的饭两个人吃”的局面。一方面工资发放都困难,一方面又源源不断进入添口。在和 R 局办公室主任交谈...人头费:只见增,不见减目前有一些机关,行政编制满了,便弄事业编制,事业编制满了,便招临时人员,逐渐形成了“一个人的活两个人干,一个人的饭两个人吃”的局面。一方面工资发放都困难,一方面又源源不断进入添口。在和 R 局办公室主任交谈时,我说:“减几个人不行吗?”他说:“减谁?就是一个临时工,也有来头;展开更多
In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model betwee...In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model between a flexspline and a wave generator. The validity of the parameterized equivalent contact model was verified by comparing the results of the analytic value of the contact model and the value calculated by the theoretical formula. The curvilinear trend of stress was obtained by changing the structural parameter of the flexspline. Based on the curvilinear trend of stress,multi-objective optimizations of key structural parameters were achieved. Flexspline,wave generator,and circular spline of a new 32-type short cylindrical cup-shaped harmonic reducer were designed and manufactured. A performance test bench to carry out tests on the harmonic reducer was designed. Contrast experiments were implemented to determine the efficiency of the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer under different conditions. The experimental results reveal that there is approximately equality in terms of efficiency between the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer. The volume of the flexspline of the new 32-type short cylindrical cup-shaped harmonic reducer is reduced by approximately 30% through multi-objective optimization. When the new 32-type short cylindrical cup-shaped harmonic reducer is used on the wheel of a rover prototype,the mass of the wheel hub is decreased by 0.42 kg. Test analysis of wheel motion verifies that the new 32-type short cylindrical cup-shaped harmonic reducer can meet the requirements regarding bearing capacity and efficiency.展开更多
The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the r...The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the resistance and pressure of three typical pneumatic resistances are obtained.Then,the method of static characteristics analysis only considering pneumatic resistances is proposed,the resistance network from gas supply to load is built up,and the mathematical model is derived from the flow rate formulas and flow conservation equations,with the compressibility of high pressure gas and temperature drop during the expansion considered in the model.Finally,the pilot spool displacement of 1.5 mm at an output pressure of 15MPa and the enlarging operating stroke of the pilot spool are taken as optimization targets,and the optimization is carried out based on genetic algorithm and the model mentioned above.The results show that the static characteristics of the EPPRV are significantly improved.The idea of static characteristics analysis and optimization based on pneumatic resistance network is valuable for the design of pneumatic components or system.展开更多
Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder r...Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm (MOGA) method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.展开更多
The karyotypes and meiotic behaviors of three Carbula species( Carbula obtusangula Reuter, C.putoni (Jakovlev)and C. sinica Hsiao et Cheng)were studied.Karyotype analyses using specific software were m...The karyotypes and meiotic behaviors of three Carbula species( Carbula obtusangula Reuter, C.putoni (Jakovlev)and C. sinica Hsiao et Cheng)were studied.Karyotype analyses using specific software were made and model karyotype chart was presented.All three species have the typical diploid chromosome number of 14 for the family Pentatomidae and X Y sex chromosomal mechanism,but the behavior of autosomes and sex chromosomes during meiosis among three species are different,and one or two supernumerary chromosomes were detected in C.putoni. These characteristics may provide some useful clues on the study of pentatomid taxonomy and phylogeny.展开更多
文摘A new adaptive cruise control (ACC) method based on the desired safety headway distance is investigated for improving the vehicle traffic safety at high speed by regulating the additional throttle opening and braking torque of driving wheels only. The selection of headway distance sensors, the determination of desired safety headway distance and desired deceleration are elaborated. The ACC flowchart and simulation, as well as signal misinformation and its resolutions are described. The simulation proves that the new ACC method is simpler and feasible. The new method is easily integrated ACC with ABS/ASR to form an organic ABS/ASR/ACC system.
基金Supported by Demonstration and Promotion Project of Shanghai Municipal Committee of Agriculture[HNKT(2015)2-7]Jiangsu Agricultural"Three New Engineering"Project[SXGC(2017)208]Jiangsu Agricultural Science and Technology Innovation Fund[CX(15)1029]~~
文摘In order to develop green good, reduce the use of chemical fertilizer and pesticide, realize "double reduction" and synergism, improve safety and quality of products, protect the ecological environment and promote the healthy and steady development of strawberry industry, the goals and key technology of fertilizer-pesticide "double reduction" and synergism for greenhouse strawberry are summed up in this paper targeting at the current situation of strawberry production and combined with the new technology achievements at home and abroad. The key technology includes six items: healthy seedling cultivating technique, soil improvement and continuous cropping obstacle treatment technique, agricultural ecological prevention tech- nique, physicochemical trap of pest control technique, biological control technique and low residual risk chemical control technique.
文摘人头费:只见增,不见减目前有一些机关,行政编制满了,便弄事业编制,事业编制满了,便招临时人员,逐渐形成了“一个人的活两个人干,一个人的饭两个人吃”的局面。一方面工资发放都困难,一方面又源源不断进入添口。在和 R 局办公室主任交谈时,我说:“减几个人不行吗?”他说:“减谁?就是一个临时工,也有来头;
基金Project(2010DFR70270) supported by the International Science and Technology Cooperation Project with RussiaProjects(50975059,61005080) supported by the National Natural Science Foundation of China+2 种基金Project(B07018) supported by "111" Program of ChinaProject(SKLRS200801A02) supported by the Foundation of State Key Laboratory of Robotics and System (Harbin Institute of Technology),ChinaProject(HIT2009061) supported by the Key Subject Laboratory Open Fund of China
文摘In order to obtain a new-type short cylindrical cup-shaped flexspline that can be applied to space mechanisms,the APDL language of ANSYS software was employed to develop a parameterized equivalent contact model between a flexspline and a wave generator. The validity of the parameterized equivalent contact model was verified by comparing the results of the analytic value of the contact model and the value calculated by the theoretical formula. The curvilinear trend of stress was obtained by changing the structural parameter of the flexspline. Based on the curvilinear trend of stress,multi-objective optimizations of key structural parameters were achieved. Flexspline,wave generator,and circular spline of a new 32-type short cylindrical cup-shaped harmonic reducer were designed and manufactured. A performance test bench to carry out tests on the harmonic reducer was designed. Contrast experiments were implemented to determine the efficiency of the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer under different conditions. The experimental results reveal that there is approximately equality in terms of efficiency between the new 32-type short cylindrical cup-shaped harmonic reducer and the conventional 32-type harmonic reducer. The volume of the flexspline of the new 32-type short cylindrical cup-shaped harmonic reducer is reduced by approximately 30% through multi-objective optimization. When the new 32-type short cylindrical cup-shaped harmonic reducer is used on the wheel of a rover prototype,the mass of the wheel hub is decreased by 0.42 kg. Test analysis of wheel motion verifies that the new 32-type short cylindrical cup-shaped harmonic reducer can meet the requirements regarding bearing capacity and efficiency.
基金Project(50575202) supported by the National Natural Science Foundation of China
文摘The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the resistance and pressure of three typical pneumatic resistances are obtained.Then,the method of static characteristics analysis only considering pneumatic resistances is proposed,the resistance network from gas supply to load is built up,and the mathematical model is derived from the flow rate formulas and flow conservation equations,with the compressibility of high pressure gas and temperature drop during the expansion considered in the model.Finally,the pilot spool displacement of 1.5 mm at an output pressure of 15MPa and the enlarging operating stroke of the pilot spool are taken as optimization targets,and the optimization is carried out based on genetic algorithm and the model mentioned above.The results show that the static characteristics of the EPPRV are significantly improved.The idea of static characteristics analysis and optimization based on pneumatic resistance network is valuable for the design of pneumatic components or system.
基金Foundation item: Supported by the National Natural Science Foundation of China (Grant No. 61174047) and the Fundamental Research Funds for the Central Universities (HEUCF041406).
文摘Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm (MOGA) method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.
文摘The karyotypes and meiotic behaviors of three Carbula species( Carbula obtusangula Reuter, C.putoni (Jakovlev)and C. sinica Hsiao et Cheng)were studied.Karyotype analyses using specific software were made and model karyotype chart was presented.All three species have the typical diploid chromosome number of 14 for the family Pentatomidae and X Y sex chromosomal mechanism,but the behavior of autosomes and sex chromosomes during meiosis among three species are different,and one or two supernumerary chromosomes were detected in C.putoni. These characteristics may provide some useful clues on the study of pentatomid taxonomy and phylogeny.