The human world is always changing; one generation is different from another. It is easy to do nothing, but rather difficult to do something without hurting the spirit. Only those who have no prejudice and do not insi...The human world is always changing; one generation is different from another. It is easy to do nothing, but rather difficult to do something without hurting the spirit. Only those who have no prejudice and do not insist on their own selves can follow the changes and not suffer. Everything has its natural ability. And as to human beings, the best way of protecting ourselves and getting an advantageous position in the human world is to forget what must be forgotten; to be"useless"; to let everything do its own work according to its own ability and have its own names.展开更多
Commonly,the classical formulas are suitable for designing the TE21-mode coupler for the operating frequency under Ka-band by ignoring the wall thickness.However,in practice,for the one operated in the Ka-band,such cl...Commonly,the classical formulas are suitable for designing the TE21-mode coupler for the operating frequency under Ka-band by ignoring the wall thickness.However,in practice,for the one operated in the Ka-band,such classical formulas are not valid and the effect of wall thicknesses should be considered.Herein,we propose a design method for the Ka-band TE21-mode coupler via computer simulations,taking into account the wall thickness.The experimental results show that using the linear twice-weighted algorithm to optimize the coupling hole size can improve the coupler performance.And the bandwidth of such coupler increases by 10%with lower coupling loss(<0.5 dB)and higher isolation(>40 dB).展开更多
The history of the philosophy oscillates between a useful knowledge and the speculation useless. This paper attempts to show a few consequences of this two perspectives named the technical interpretation of the knowle...The history of the philosophy oscillates between a useful knowledge and the speculation useless. This paper attempts to show a few consequences of this two perspectives named the technical interpretation of the knowledge and the essential interpretation of the knowledge. The proposal of this paper is to show that the philosophy is between the two frontiers delimiters： the border delimiters of the field and the city and the border between the useful and the useless, and indicate the relative importance of useful and useless for these perspectives.展开更多
The Useless Web收集了大量来自世界各地的无聊网站,用户每点击一次PLEASE按钮,就会为你随机挑选一个无聊网站。虽然这种行为看起来挺无聊的,不过其中确实有部分网站比较接地气,你可能遇到一个冷到不行的笑话,看到一张让人惊叹的图片，...The Useless Web收集了大量来自世界各地的无聊网站,用户每点击一次PLEASE按钮,就会为你随机挑选一个无聊网站。虽然这种行为看起来挺无聊的,不过其中确实有部分网站比较接地气,你可能遇到一个冷到不行的笑话,看到一张让人惊叹的图片，或者偶遇其他的惊喜。展开更多
文摘The human world is always changing; one generation is different from another. It is easy to do nothing, but rather difficult to do something without hurting the spirit. Only those who have no prejudice and do not insist on their own selves can follow the changes and not suffer. Everything has its natural ability. And as to human beings, the best way of protecting ourselves and getting an advantageous position in the human world is to forget what must be forgotten; to be"useless"; to let everything do its own work according to its own ability and have its own names.
基金the National Natural Science Foundation of China under Grant.No.61627817.
文摘Commonly,the classical formulas are suitable for designing the TE21-mode coupler for the operating frequency under Ka-band by ignoring the wall thickness.However,in practice,for the one operated in the Ka-band,such classical formulas are not valid and the effect of wall thicknesses should be considered.Herein,we propose a design method for the Ka-band TE21-mode coupler via computer simulations,taking into account the wall thickness.The experimental results show that using the linear twice-weighted algorithm to optimize the coupling hole size can improve the coupler performance.And the bandwidth of such coupler increases by 10%with lower coupling loss(<0.5 dB)and higher isolation(>40 dB).
文摘The history of the philosophy oscillates between a useful knowledge and the speculation useless. This paper attempts to show a few consequences of this two perspectives named the technical interpretation of the knowledge and the essential interpretation of the knowledge. The proposal of this paper is to show that the philosophy is between the two frontiers delimiters： the border delimiters of the field and the city and the border between the useful and the useless, and indicate the relative importance of useful and useless for these perspectives.
