( 2 ) the causation that the caustic phenomena of electromagnetic wave propagation in two - dimension concave reflectors occurs and the types of singularities in caustic fields are investigated, and the conclusion that there are two types of singularities ( fold and cusp ) in caustic fields in two - dimension concave reflectors is obtained ; by symplectic geometrical method, formulations of computing wave fields in and far away from caustic fields in two - dimension concave reflectors are deduced, and the results are plotted in pictures. ( 3 ) the cause of the caustic phenomena of electromagnetic wave propagation in three - dimension concave reflectors and the types of singularities in caustic fields is discussed, and the conclusion that there are three main types of singularities ( fold, cusp and swallowtail ) in caustic fields in three - dimension concave reflectors is obtained ; by symplectic geometrical method, the formulae of computing wave fields in and far away from caustic fields in three - dimension concave reflectors are deduced. particularly, the wave fields in ellipsoid concave reflector are computed, and the results displayed in special sections are given
論文主要包括三個方面: ( 1 )分析了
凹面反射的焦散現象,給出了不同
凹面反射的焦散圖; ( 2 )分析了二維
凹面反射波動場焦散現象產生的原因及焦散區奇性的種類,得出了二維
凹面反射波動場焦散區奇性主要有折疊( fold )和尖點( cusp )兩種的結論,利用辛幾何方法構造了圓錐曲面反射波動場非焦散區和焦散區的通用計算公式,並給出了圓柱面、橢圓柱面及雙曲柱面反射的計算結果; ( 3 )分析了三維
凹面反射波動場焦散現象產生的原因及焦散區奇性的種類,得出了三維
凹面反射波動場焦散區奇性主要有折疊( fom 、尖點kusp和燕
尾k )三種的結論,提出了利用辛幾何方法計算三維
凹面反射波動場非焦散區和焦散區的計算方法,並給出了三軸不等橢球體
凹面反射波動場的計算結果剖面圖。
1b ) steel parts must have polished angles and their visible surfaces smoothed down. screw heads have to be polished, with their slots and rims chamfered
所有鋼制零件的邊緣必須削角、打磨、拋光使其如鏡面般光亮。所有螺絲帽的邊緣及
凹口都要削角拋光,螺絲
尾則須做平面或球面拋光。
The stern of river / sea barge is designed to the notch form to adapt the connected requirement between pusher and barge by couple - pins
摘要為適應推船與駁船間的二銷聯接方式,江海駁具有
凹槽
尾型,船組的阻力與常規船舶有較大的差異。
The puppies were found inside the boot of the man s vehicle by the police when he was stopped at the shek chung au roadblock
警方在石涌
凹的路障截查該男子的汽車時,在車
尾箱發現該批小狗。
Nol would connect west rail at kam sheung road to the new lok ma chau boundary crossing and kwu tung station, both to be completed under the spur line project, through au tau, ngau tam mei and san tin
北環線將會由西鐵錦上路站經
凹頭牛潭
尾及新田,連接新落馬洲過境通道及古洞車站,這兩個項目將于落馬洲支線項目下完成。
A rattlesnake, for instance, has one small pit on each side of its head, filled with thousands of receptor cells, which are actually microscopic - sized infrared sensors
例如響尾蛇在頭部兩側小凹坑裡的器官充滿數千個受體細胞,這實際上就是顯微的紅外線感受器。