The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that...The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.展开更多
The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM...The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.展开更多
Aiming at some weapon systems with shooting domain,the stochastic passage characteristics of the barrel were studied.On the basis of the exact definition of the stochastic passage characteristics,its opportunity-await...Aiming at some weapon systems with shooting domain,the stochastic passage characteristics of the barrel were studied.On the basis of the exact definition of the stochastic passage characteristics,its opportunity-awaiting time,residence time and stochastic passage period were given by using the transition probability matrix,and they all obeyed the geometry distributions.Their means and variances were also derived,and the relations between the time indexes and the structure and parameters of weapon control system were established.Finally,the creditability of the conclusions was verified by the test data of weapon system in proving ground.展开更多
This paper presents four patterns of reference-return positions for CNC machine tools and analyses some causes of return reference troubles by showing typical examples of trouble shooting.Finally,it introduces several...This paper presents four patterns of reference-return positions for CNC machine tools and analyses some causes of return reference troubles by showing typical examples of trouble shooting.Finally,it introduces several methods of trouble shooting.展开更多
根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林...根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林分的生态功能提供了依据.该项研究丰富了森林病理学内容,补充了松枯梢病的研究成果,为林间生产应用提供了科学依据和技术方法.展开更多
文摘The occurrence regularity of Phyllocnistis citreua in northern Guizhou was investigated,and the relationship between summer shoot controlling of citrus and occurrence of P. citreua was studied. The results showed that P. citreua occurred from May to September every year in northern Guizhou,and the occurrence reached the peak from early May to late June and from early July to late August. The occurrence in early and mid July was the most serious. The free-sprouting time had a close relationship with occurrence quantity and damage level of P. citreua. The earlier the free-sprouting time was,the greater the occurrence quantity and damage level of P. citreua was. The integrated control techniques focused on timely erasing summer shoots and controlling shoots were suggested to use in production,in order to control the occurrence of P. citreua.
基金supported by the National Natural Science Foundation of China (11472058)
文摘The optimal control of multibody spacecraft during the stretching process of solar arrays is investigated,and a hybrid optimization strategy based on Gauss pseudospectral method（GPM） and direct shooting method（DSM） is presented. First, the elastic deformation of flexible solar arrays was described approximately by the assumed mode method, and a dynamic model was established by the second Lagrangian equation. Then, the nonholonomic motion planning problem is transformed into a nonlinear programming problem by using GPM. By giving fewer LG points, initial values of the state variables and control variables were obtained. A serial optimization framework was adopted to obtain the approximate optimal solution from a feasible solution. Finally, the control variables were discretized at LG points, and the precise optimal control inputs were obtained by DSM. The optimal trajectory of the system can be obtained through numerical integration. Through numerical simulation, the stretching process of solar arrays is stable with no detours, and the control inputs match the various constraints of actual conditions.The results indicate that the method is effective with good robustness.
基金Sponsored by National Defense Fundation of China(9140C300602080C30)NUST Research Fundation of China(2010ZYTS050)
文摘Aiming at some weapon systems with shooting domain,the stochastic passage characteristics of the barrel were studied.On the basis of the exact definition of the stochastic passage characteristics,its opportunity-awaiting time,residence time and stochastic passage period were given by using the transition probability matrix,and they all obeyed the geometry distributions.Their means and variances were also derived,and the relations between the time indexes and the structure and parameters of weapon control system were established.Finally,the creditability of the conclusions was verified by the test data of weapon system in proving ground.
文摘This paper presents four patterns of reference-return positions for CNC machine tools and analyses some causes of return reference troubles by showing typical examples of trouble shooting.Finally,it introduces several methods of trouble shooting.
文摘根据生态环境学和现代森林病理学的原理与方法,通过多学科联合攻关,深入系统地研究了樟子松(Pinussylvestris var. mongolica)枯死的难题,搞清了樟子松枯死的起因与机理.提出以营林措施为主的防治技术对策,为经营樟子松人工林、增强林分的生态功能提供了依据.该项研究丰富了森林病理学内容,补充了松枯梢病的研究成果,为林间生产应用提供了科学依据和技术方法.
