In this paper, time-optimal control problem for a liner n× n co-operative parabolic system involving Laplace operator is considered. This problem is, steering an initial state y(0)=u?, with control u?so that an o...In this paper, time-optimal control problem for a liner n× n co-operative parabolic system involving Laplace operator is considered. This problem is, steering an initial state y(0)=u?, with control u?so that an observation y(t) hitting a given target set in minimum time. First, the existence and uniqueness of solutions of such system under conditions on the coefficients are proved. Afterwards necessary and sufficient conditions of optimality are obtained. Finally a scaler case is given.展开更多
Nowadays,chatting programs have become very popular among TV audience,because they are well integrated with information,entertainment and leisure.They can bring a lot of laughter as well as elicitation to the audience...Nowadays,chatting programs have become very popular among TV audience,because they are well integrated with information,entertainment and leisure.They can bring a lot of laughter as well as elicitation to the audience.However,with the sharp increase of chatting programs on television,some programs which are not well designed emerge at an amazing rate.Our au dience always have a bad feeling to these programs and even mislead by them.My paper analyzes some chatting programs from the perspective of Grice's co-operative principles,and gives some suggestion for how to make chatting program go more smoothly.展开更多
Two strategies extended the single-cascade methods from a compressible three-dimensional inverse method for radial and mixed flow turbomachines to two three-dimensional multi-cascade co-design methods for single-stage...Two strategies extended the single-cascade methods from a compressible three-dimensional inverse method for radial and mixed flow turbomachines to two three-dimensional multi-cascade co-design methods for single-stage centrifugal compressors.These two three-dimensional methods and a typical quasi-threedimensional streamline curvature through-flow inverse method were employed to design the same subsonic high-speed single-stage centrifugal compressors.The compressor performances were simulated by a commercial Reynolds averaged Navier-Stokes(RANS) equations solver.The studies show that two three-dimensional codesign methods are reasonable and feasible.It was found that : firstly the blade camber angle designed by the three-dimensional methods was larger than that designed by the quasi-three-dimensional method;and secondly with regard to two three-dimensional methods with different boundary conditions,the co-design result differences between the diffusers were small,but those between the deswirlers were relatively large.展开更多
文摘In this paper, time-optimal control problem for a liner n× n co-operative parabolic system involving Laplace operator is considered. This problem is, steering an initial state y(0)=u?, with control u?so that an observation y(t) hitting a given target set in minimum time. First, the existence and uniqueness of solutions of such system under conditions on the coefficients are proved. Afterwards necessary and sufficient conditions of optimality are obtained. Finally a scaler case is given.
文摘Nowadays,chatting programs have become very popular among TV audience,because they are well integrated with information,entertainment and leisure.They can bring a lot of laughter as well as elicitation to the audience.However,with the sharp increase of chatting programs on television,some programs which are not well designed emerge at an amazing rate.Our au dience always have a bad feeling to these programs and even mislead by them.My paper analyzes some chatting programs from the perspective of Grice's co-operative principles,and gives some suggestion for how to make chatting program go more smoothly.
基金Programme of Introducing Talents of Discipline to Universities(B08009)
文摘Two strategies extended the single-cascade methods from a compressible three-dimensional inverse method for radial and mixed flow turbomachines to two three-dimensional multi-cascade co-design methods for single-stage centrifugal compressors.These two three-dimensional methods and a typical quasi-threedimensional streamline curvature through-flow inverse method were employed to design the same subsonic high-speed single-stage centrifugal compressors.The compressor performances were simulated by a commercial Reynolds averaged Navier-Stokes(RANS) equations solver.The studies show that two three-dimensional codesign methods are reasonable and feasible.It was found that : firstly the blade camber angle designed by the three-dimensional methods was larger than that designed by the quasi-three-dimensional method;and secondly with regard to two three-dimensional methods with different boundary conditions,the co-design result differences between the diffusers were small,but those between the deswirlers were relatively large.
