The waterfront space is a specific and perfect open space for people to experience the city.Daily entertainment,leisure,shopping,sports and other activities can be carried out in the waterfront slow-motility space.The...The waterfront space is a specific and perfect open space for people to experience the city.Daily entertainment,leisure,shopping,sports and other activities can be carried out in the waterfront slow-motility space.There are three types of slow-mover in urban waterfront space namely walking,stop or stay,and riding.Analysis of their behavioral characteristics and the difference of different people can help to clarify the design requirements and produce a waterfront space that will better meets people’s functional needs.展开更多
A tubular moving-magnet linear oscillating motor（TMMLOM） has merits of high efficiency and excellent dynamic capability. To enhance the thrust performance, quasi-Halbach permanent magnet（PM） arrays are arranged on...A tubular moving-magnet linear oscillating motor（TMMLOM） has merits of high efficiency and excellent dynamic capability. To enhance the thrust performance, quasi-Halbach permanent magnet（PM） arrays are arranged on its mover in the application of a linear electro-hydrostatic actuator in more electric aircraft. The arrays are assembled by several individual segments, which lead to gaps between them inevitably. To investigate the effects of the gaps on the radial magnetic flux density and the machine thrust in this paper, an analytical model is built considering both axial and radial gaps. The model is validated by finite element simulations and experimental results.Distributions of the magnetic flux are described in condition of different sizes of radial and axial gaps. Besides, the output force is also discussed in normal and end windings. Finally, the model has demonstrated that both kinds of gaps have a negative effect on the thrust, and the linear motor is more sensitive to radial ones.展开更多
Color descriptors are one of the important features used in content-based in, age retrieval. The dominant color descriptor （DCD） represents a few perceptually dominant colors in an image through color quantization. ...Color descriptors are one of the important features used in content-based in, age retrieval. The dominant color descriptor （DCD） represents a few perceptually dominant colors in an image through color quantization. For image retrieval based on DCD, the earth mover＇s distance （EMD） and the optimal color composition distance were proposed to measure the dissimilarity between two images. Although providing good retrieval results, both methods are too time-consuming to be used in a large image database. To solve the problem, we propose a new distance function that calculates an approximate earth mover＇s distance in linear time. To calculate the dissimilarity in linear time, the proposed approach employs the space-filling curve for multidimensional color space. To improve the accuracy, the proposed approach uses multiple curves and adjusts the color positions. As a result, our approach achieves order-of-magnitude time improvement but incurs small errors. We have performed extensive experiments to show the effectiveness and efficiency of the proposed approach. The results reveal that our approach achieves almost the same results with the EMD in linear time.展开更多
Background Sextupoles in the storage ring of HEPS will be adjusted based on beam trajectory.The mechanical design of a beam-based alignment sextupole mover should be developed.The motion accuracy of the mover should b...Background Sextupoles in the storage ring of HEPS will be adjusted based on beam trajectory.The mechanical design of a beam-based alignment sextupole mover should be developed.The motion accuracy of the mover should be better than 5µm under 450 kg load of sextupoles.The movement range is required to be±0.3 mm in both horizontal direction and vertical direction.And the first-order natural frequency of the magnet support system which include movers should be higher than 54 Hz.Purpose The purpose of this paper is to design a mover prototype and to realize its movement performance and equivalent stiffness.And to find the difficulties of development of this mover.Method Interferometer is used to measure the motion accuracy,and pressure accelerometer is used to test the mover equivalent stiffness.Combining with the actual measurement results of equivalent stiffness,the natural frequency of the magnet support system is simulated.Result The motion accuracy reaches to 5.3µm in vertical direction and 1µm in horizontal direction,respectively.The equivalent stiffness of the mover prototype can just able to meet the requirement of frequency of the HEPS magnet support system.Unwanted movement coupling has occurred during the mover exercises in vertical direction.Conclusions Through the research of experimental mover prototype,the methods have been learnt to improve the movement performance and equivalent stiffness of the mover based on sliding friction under high load.However,further researches and improvements are necessary to fix the coupling error during the vertical movement.展开更多
In keeping with a view that is explicitly formulated by Aristotle in his Motion of Animals, general kinetic principles must be specified according to the different types of movable entities existing in the universe. A...In keeping with a view that is explicitly formulated by Aristotle in his Motion of Animals, general kinetic principles must be specified according to the different types of movable entities existing in the universe. At issue, essentially, are the motions of the stars and the motions of animals. Whereas the cosmological immovable mover is the object of two complementary analyses （in Bk. Ⅷ of Physics and in Chs. 6 and 7 of Bk. Ⅻ of Metaphysics）, information on the immovability of the first mover responsible for animal motion is to be found in the psychological and psycho-physiological treatises （On the Soul, in Bk. Ⅰ, Chs. 3 and 4, and in Bk. Ⅲ, Ch. 10 and in Ch. 6 of the Motion of Animals）. But it is also found in Ch. 7, Bk. Ⅻ of the Metaphysics, in the very context of the argument concerning the absolutely first immovable mover of the world. This suggests that the two types of motion, that of the stars and that of animals, however distinct the arguments about them are, rest on a single scheme, and maybe even on a common principle. This is liable to surprise us, as much as stars and animals appear to us to belong to heterogeneous orders of reality. But the situation is different for Aristotle, who, as attentive as he is to differences, tends nonetheless to conceive the stars as living things of a particular kind. This fact is the source of a series of difficulties that Aristotle generously left for his many commentators to solve. Aim of this text, which was initially directed to a larger audience, is to set some of these complex issues in both simple and up to date terms.展开更多
In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunt...In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunteers in the booth invited visitors to have a go at running the machine, which was developed by U.S. company Intuitive Surgical and has been used in 6 million successful surgeries worldwide. Over 110,000 of these were done in China, which has around 80 such robots in use in hospitals.展开更多
基金supported by the Ministry of Education Humanities and Social Sciences Research Project(Grant No.19YJC760024).
文摘The waterfront space is a specific and perfect open space for people to experience the city.Daily entertainment,leisure,shopping,sports and other activities can be carried out in the waterfront slow-motility space.There are three types of slow-mover in urban waterfront space namely walking,stop or stay,and riding.Analysis of their behavioral characteristics and the difference of different people can help to clarify the design requirements and produce a waterfront space that will better meets people’s functional needs.
基金supports of National Basic Research Program of China(973 Program)(No.2014CB046402)National Natural Science Foundation of China(Nos.51620105010,51575019,51675019,51505015)111 Program of China
文摘A tubular moving-magnet linear oscillating motor（TMMLOM） has merits of high efficiency and excellent dynamic capability. To enhance the thrust performance, quasi-Halbach permanent magnet（PM） arrays are arranged on its mover in the application of a linear electro-hydrostatic actuator in more electric aircraft. The arrays are assembled by several individual segments, which lead to gaps between them inevitably. To investigate the effects of the gaps on the radial magnetic flux density and the machine thrust in this paper, an analytical model is built considering both axial and radial gaps. The model is validated by finite element simulations and experimental results.Distributions of the magnetic flux are described in condition of different sizes of radial and axial gaps. Besides, the output force is also discussed in normal and end windings. Finally, the model has demonstrated that both kinds of gaps have a negative effect on the thrust, and the linear motor is more sensitive to radial ones.
基金supported by the MSIP(Ministry of Science,ICT,and Future Planning),Korea,under the IT-CRSP(IT Convergence Research Support Program)with No.NIPA-2013-H0401-13-1001 supervised by the NIPA(National IT Industry Promotion Agency)the NRF(National Research Foundation)of Korea Grant funded by the Korean Government with No.NRF-2011-330-B00076supported by the Basic Science Research Program through the NRF funded by the Ministry of Education,Science and Technology of Korea under Grant Nos.2012R1A1A2007817 and 2013R1A6A3A03027153
文摘Color descriptors are one of the important features used in content-based in, age retrieval. The dominant color descriptor （DCD） represents a few perceptually dominant colors in an image through color quantization. For image retrieval based on DCD, the earth mover＇s distance （EMD） and the optimal color composition distance were proposed to measure the dissimilarity between two images. Although providing good retrieval results, both methods are too time-consuming to be used in a large image database. To solve the problem, we propose a new distance function that calculates an approximate earth mover＇s distance in linear time. To calculate the dissimilarity in linear time, the proposed approach employs the space-filling curve for multidimensional color space. To improve the accuracy, the proposed approach uses multiple curves and adjusts the color positions. As a result, our approach achieves order-of-magnitude time improvement but incurs small errors. We have performed extensive experiments to show the effectiveness and efficiency of the proposed approach. The results reveal that our approach achieves almost the same results with the EMD in linear time.
文摘Background Sextupoles in the storage ring of HEPS will be adjusted based on beam trajectory.The mechanical design of a beam-based alignment sextupole mover should be developed.The motion accuracy of the mover should be better than 5µm under 450 kg load of sextupoles.The movement range is required to be±0.3 mm in both horizontal direction and vertical direction.And the first-order natural frequency of the magnet support system which include movers should be higher than 54 Hz.Purpose The purpose of this paper is to design a mover prototype and to realize its movement performance and equivalent stiffness.And to find the difficulties of development of this mover.Method Interferometer is used to measure the motion accuracy,and pressure accelerometer is used to test the mover equivalent stiffness.Combining with the actual measurement results of equivalent stiffness,the natural frequency of the magnet support system is simulated.Result The motion accuracy reaches to 5.3µm in vertical direction and 1µm in horizontal direction,respectively.The equivalent stiffness of the mover prototype can just able to meet the requirement of frequency of the HEPS magnet support system.Unwanted movement coupling has occurred during the mover exercises in vertical direction.Conclusions Through the research of experimental mover prototype,the methods have been learnt to improve the movement performance and equivalent stiffness of the mover based on sliding friction under high load.However,further researches and improvements are necessary to fix the coupling error during the vertical movement.
文摘In keeping with a view that is explicitly formulated by Aristotle in his Motion of Animals, general kinetic principles must be specified according to the different types of movable entities existing in the universe. At issue, essentially, are the motions of the stars and the motions of animals. Whereas the cosmological immovable mover is the object of two complementary analyses （in Bk. Ⅷ of Physics and in Chs. 6 and 7 of Bk. Ⅻ of Metaphysics）, information on the immovability of the first mover responsible for animal motion is to be found in the psychological and psycho-physiological treatises （On the Soul, in Bk. Ⅰ, Chs. 3 and 4, and in Bk. Ⅲ, Ch. 10 and in Ch. 6 of the Motion of Animals）. But it is also found in Ch. 7, Bk. Ⅻ of the Metaphysics, in the very context of the argument concerning the absolutely first immovable mover of the world. This suggests that the two types of motion, that of the stars and that of animals, however distinct the arguments about them are, rest on a single scheme, and maybe even on a common principle. This is liable to surprise us, as much as stars and animals appear to us to belong to heterogeneous orders of reality. But the situation is different for Aristotle, who, as attentive as he is to differences, tends nonetheless to conceive the stars as living things of a particular kind. This fact is the source of a series of difficulties that Aristotle generously left for his many commentators to solve. Aim of this text, which was initially directed to a larger audience, is to set some of these complex issues in both simple and up to date terms.
文摘In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunteers in the booth invited visitors to have a go at running the machine, which was developed by U.S. company Intuitive Surgical and has been used in 6 million successful surgeries worldwide. Over 110,000 of these were done in China, which has around 80 such robots in use in hospitals.
