通过推mAWS成功奠定全球范围内的公有云计算主导者地位，是亚马逊帝国面对未来赢下的最大先机。但是随着越来越多的IT和电信巨头甚至各国政府在云计算领域加大关注和投入，“亚马逊模式”还能领跑多久？而将这种模式Copy to China的中...通过推mAWS成功奠定全球范围内的公有云计算主导者地位，是亚马逊帝国面对未来赢下的最大先机。但是随着越来越多的IT和电信巨头甚至各国政府在云计算领域加大关注和投入，“亚马逊模式”还能领跑多久？而将这种模式Copy to China的中国电信在大肆投建数据中心的同时，是否应该有更多反思？展开更多
In this study, a multi-input/multi-output（MIMO） time-delay feedback controller is designed to actively suppress the flutter instability of a multiple-actuated-wing（MAW） wind tunnel model in the low subsonic flow r...In this study, a multi-input/multi-output（MIMO） time-delay feedback controller is designed to actively suppress the flutter instability of a multiple-actuated-wing（MAW） wind tunnel model in the low subsonic flow regime. The unsteady aerodynamic forces of the MAW model are computed based on the doublet-lattice method（DLM）. As the first attempt, the conventional linear quadratic-Gaussian（LQG） controller is designed to actively suppress the flutter of the MAW model. However, because of the time delay in the control loop, the wind tunnel tests illustrate that the LQG-controlled MAW model has no guaranteed stability margins. To compensate the time delay, hence, a time-delay filter, approximated via the first-order Pade approximation, is added to the LQG controller. Based on the time-delay feedback controller, a new digital control system is constructed by using a fixed-point and embedded digital signal processor（DSP） of high performance. Then, a number of wind tunnel tests are implemented based on the digital control system.The experimental results show that the present time-delay feedback controller can expand the flutter boundary of the MAW model and suppress the flutter instability of the open-loop aeroelastic system effectively.展开更多
The results of the study Crocus korolkovii Regel & Maw, were introduced into the Tashkent Botanical Garden. Bioecological features, morphological and anatomical characteristics of Crocus korolkovii were studied. P...The results of the study Crocus korolkovii Regel & Maw, were introduced into the Tashkent Botanical Garden. Bioecological features, morphological and anatomical characteristics of Crocus korolkovii were studied. Phenology was studied by I.N. Beideman, biology bloom by A.P. Ponomarev, breeding and seed production of plants by T.T. Rakhimova. The study of the biology of flowering determined the optimal humidity, air temperature and soil surface. The anatomic study used fresh tissue samples which were fixed in 70% alcohol. A cross-section of the sheet and the structure of the flower in the introduction of conditions were studied.展开更多
基金supported in part by the National Natural Science Foundation of China (No. 10972100)
文摘In this study, a multi-input/multi-output（MIMO） time-delay feedback controller is designed to actively suppress the flutter instability of a multiple-actuated-wing（MAW） wind tunnel model in the low subsonic flow regime. The unsteady aerodynamic forces of the MAW model are computed based on the doublet-lattice method（DLM）. As the first attempt, the conventional linear quadratic-Gaussian（LQG） controller is designed to actively suppress the flutter of the MAW model. However, because of the time delay in the control loop, the wind tunnel tests illustrate that the LQG-controlled MAW model has no guaranteed stability margins. To compensate the time delay, hence, a time-delay filter, approximated via the first-order Pade approximation, is added to the LQG controller. Based on the time-delay feedback controller, a new digital control system is constructed by using a fixed-point and embedded digital signal processor（DSP） of high performance. Then, a number of wind tunnel tests are implemented based on the digital control system.The experimental results show that the present time-delay feedback controller can expand the flutter boundary of the MAW model and suppress the flutter instability of the open-loop aeroelastic system effectively.
文摘The results of the study Crocus korolkovii Regel & Maw, were introduced into the Tashkent Botanical Garden. Bioecological features, morphological and anatomical characteristics of Crocus korolkovii were studied. Phenology was studied by I.N. Beideman, biology bloom by A.P. Ponomarev, breeding and seed production of plants by T.T. Rakhimova. The study of the biology of flowering determined the optimal humidity, air temperature and soil surface. The anatomic study used fresh tissue samples which were fixed in 70% alcohol. A cross-section of the sheet and the structure of the flower in the introduction of conditions were studied.
