The 4TPS-PS parallel platform designed for a stabilization and automatic tracking system is a novel lower-mobility parallel mechanism. In the first part of this paper, the structure of the platform is described and th...The 4TPS-PS parallel platform designed for a stabilization and automatic tracking system is a novel lower-mobility parallel mechanism. In the first part of this paper, the structure of the platform is described and the kinematics model is built. The workspace of the platform is defined as the full reachable rotation workspace when the Z coordinate dimension of the upper plate varies continuously. A fast searching method of the full reachable workspace is presented, after which the inverse kinematics of the platform is deduced. The forward and inverse solutions of the speed and force of the platform are deduced. According to the characteristic of the 4TPS-PS platform’s structure, a fast searching algorithm of the maximum generalized speed and maximum generalized force output by the upper plate is put forward based on the forward and inverse solutions of the platform’s speed and force. The 4TPS-PS platform prototype built by the State Key Laboratory of Fluid Power Transmission and Control of China is taken as the research subject. The full reachable rotation workspace of the prototype is computed out and analyzed. The curves of maximum generalized speed and maximum generalized force of the prototype are computed out and plotted. Finally, the com- puting and analyzing results of the operating characteristics are confirmed through the experiment.展开更多
Based on surfaced-related multiple elimination （SRME） , this research has derived the methods on multiples elimination in the inverse data space. Inverse data processing means moving seismic data from forwar...Based on surfaced-related multiple elimination （SRME） , this research has derived the methods on multiples elimination in the inverse data space. Inverse data processing means moving seismic data from forward data space （FDS） to inverse data space （ IDS） . The surface-related multiples and primaries can then be sepa-rated in the IDS, since surface-related multiples wi l l form a focus region in the IDS. Muting the multiples ener-gy can achieve the purpose of multiples elimination and avoid the damage to primaries energy during the process of adaptive subtraction. Randomized singular value decomposition （ RSYD） is used to enhance calculation speed and improve the accuracy in the conversion of FDS to IDS. The synthetic shot record of the salt dome model shows that the relationship between primaries and multiples is simple and clear, and RSVD can easily eliminate multiples and save primaries energy. Compared with conventional multiples elimination methods and ordinary methods of multiples elimination in the inverse data space, this technique has an advantage of high cal-culation speed and reliable outcomes.展开更多
The history of international industrialization shows that Latin American countries and former Soviet Union and Eastern European countries experienced a siginificant drop in economic growth and fell into the middle-inc...The history of international industrialization shows that Latin American countries and former Soviet Union and Eastern European countries experienced a siginificant drop in economic growth and fell into the middle-income trap when their per capita GDP reached 4,000-7,000 international dollar （based on the 1990 prices） as a result of long-term implemented import-oriented strategy and planned economic system. Fortunately, China adopted reform and opening-up policy beginning at a lower development phase and achieved sustained high-speed growth for more than thirty years. Currently, China has surpassed the phase which the above-mentioned countries fell into the middle-income trap. On the other side, experiences of successful runner-ups show that when per capita GDP reached II,000 international dollar （based on the 1990 prices）, economic growth speed will present regularly ＂natural drop ＂. Without internal and external shocks, China＇s economy is expected to reach this level by 2015 and the potential growth rate will possibly drop significantly. In this regard, China＇s toughest challenges will be whether it can effectively prevent and solve the financial risks accumulated during high-speed growth and make a shift to innovation-driven growth model Time is pressing for addressing the above challenges. A fundamental change in the growth model depends on the intensification of reform, in particular, the promotion of an ＂participatory and facilitative reform ＂approach.展开更多
基金Project (No. 50375139) supported by the National Natural Science Foundation of China
文摘The 4TPS-PS parallel platform designed for a stabilization and automatic tracking system is a novel lower-mobility parallel mechanism. In the first part of this paper, the structure of the platform is described and the kinematics model is built. The workspace of the platform is defined as the full reachable rotation workspace when the Z coordinate dimension of the upper plate varies continuously. A fast searching method of the full reachable workspace is presented, after which the inverse kinematics of the platform is deduced. The forward and inverse solutions of the speed and force of the platform are deduced. According to the characteristic of the 4TPS-PS platform’s structure, a fast searching algorithm of the maximum generalized speed and maximum generalized force output by the upper plate is put forward based on the forward and inverse solutions of the platform’s speed and force. The 4TPS-PS platform prototype built by the State Key Laboratory of Fluid Power Transmission and Control of China is taken as the research subject. The full reachable rotation workspace of the prototype is computed out and analyzed. The curves of maximum generalized speed and maximum generalized force of the prototype are computed out and plotted. Finally, the com- puting and analyzing results of the operating characteristics are confirmed through the experiment.
文摘Based on surfaced-related multiple elimination （SRME） , this research has derived the methods on multiples elimination in the inverse data space. Inverse data processing means moving seismic data from forward data space （FDS） to inverse data space （ IDS） . The surface-related multiples and primaries can then be sepa-rated in the IDS, since surface-related multiples wi l l form a focus region in the IDS. Muting the multiples ener-gy can achieve the purpose of multiples elimination and avoid the damage to primaries energy during the process of adaptive subtraction. Randomized singular value decomposition （ RSYD） is used to enhance calculation speed and improve the accuracy in the conversion of FDS to IDS. The synthetic shot record of the salt dome model shows that the relationship between primaries and multiples is simple and clear, and RSVD can easily eliminate multiples and save primaries energy. Compared with conventional multiples elimination methods and ordinary methods of multiples elimination in the inverse data space, this technique has an advantage of high cal-culation speed and reliable outcomes.
文摘The history of international industrialization shows that Latin American countries and former Soviet Union and Eastern European countries experienced a siginificant drop in economic growth and fell into the middle-income trap when their per capita GDP reached 4,000-7,000 international dollar （based on the 1990 prices） as a result of long-term implemented import-oriented strategy and planned economic system. Fortunately, China adopted reform and opening-up policy beginning at a lower development phase and achieved sustained high-speed growth for more than thirty years. Currently, China has surpassed the phase which the above-mentioned countries fell into the middle-income trap. On the other side, experiences of successful runner-ups show that when per capita GDP reached II,000 international dollar （based on the 1990 prices）, economic growth speed will present regularly ＂natural drop ＂. Without internal and external shocks, China＇s economy is expected to reach this level by 2015 and the potential growth rate will possibly drop significantly. In this regard, China＇s toughest challenges will be whether it can effectively prevent and solve the financial risks accumulated during high-speed growth and make a shift to innovation-driven growth model Time is pressing for addressing the above challenges. A fundamental change in the growth model depends on the intensification of reform, in particular, the promotion of an ＂participatory and facilitative reform ＂approach.
