焦點寬度 的英文怎麼說
中文拼音 [jiāodiǎnkuāndù]
焦點寬度
英文
focus width-
The conclusions are as follows : the ultrasonic intensity is proportion to the laser intensity ; the ultrasonic induced by a laser line source has much more advantages than by a laser point source, such as stronger energy, higher snr, more directivity and shape ; the intensity of cfpi ' s output signal is linear with ultrasonic vibration velocity, and is effected by incidence angle and scattered angle ; snr will increase by reducing cfpi ' s bandwidth, reducing incidence angle, increasing cavity ' s length and reflectivity
在分析點光源激勵聲表面波機理的基礎上，求出了線光源激勵的超聲振動的位移表達式，發現線光源激勵的近場區表面波具有波形好，信噪比高，指向性好，幅度強等特點。通過理論推導，得出共焦fabry - perot干涉儀的輸出光強除了與樣品表面的振動速度成正比，並與入射角和散射角有關；適當減小cfpi的帶寬，增加腔長，增大鏡面反射率，或者減小檢測入射角都可以提高系統的信噪比。By the method of matrix optics, the waist width and imaging distance of gaussian beams through the coupling system are calculated. by the result of the calculation, a set of double planoconvex lens coupling system are designed and manufactured. the coupling efficiency is up to 92 %
利用矩陣光學的方法，計算了高斯光束經耦合系統聚焦后的像距和束腰寬度，以此為指導設計加工了一套雙平凸鏡耦合系統，耦合效率達92 ；在以上基礎上研究了泵浦光與振蕩光在激光晶體中的匹配，計算出了泵浦光經耦合系統后的最佳焦點位置。For 15mhz immersion focusing ultrasonic testing signal, the proper sampling frequency is 90mhz, the appropriate strobe - width is 1. 2us and the sampling error less than 20 %
本文的試驗分析結果表明，對于中心頻率為15mhz的水浸聚焦探頭，其采樣頻率應不低於90mhz ，閘門寬度為1 . 2us ，特徵點的采樣誤差應不大於20 。Thirdly, a modified extended chirp scaling ( ecs ) algorithm is presented, which solves the problem of producding fine focused images in the class of chirp scaling ( cs ) algorithm. lt can be used for uwb - sar imaging effectively. the phas e error produced by cs operation are analyzed. a windowed process in two dimension frequency domain before cs operation are proposed. it can improve the quality of image and widen the effectively swath and increase the peak to sidelobe ratio ( pslr )
然後針對chirpscaling （ cs ）類演算法不能對參考點精確聚焦的問題，提出了一種改進的擴展cs （ ecs ）演算法，實現了對uwb - sar的高效成像；分析了cs操作產生的相位誤差，提出在cs操作之前在二維頻率域對信號加窗，除有效提高信號的峰值旁瓣比（ pslr ）外，還可以提高圖像質量，增加有效測繪帶寬度。分享友人