Short - time fourier transform and time - frequency distribution series are applied to time - frequency imaging . time - frequency distribution series based on wavelet transform is discussed . , and a new time - frequency tool : frequency - shear distribution is introduced into radar imaging fields 討論了基于小波變換的時頻分布級數(shù),把一種新的時頻分析工具? ?頻率-切變分布應(yīng)用于時頻成像。
The main contributions of this work are included as follows : ( 1 ) numerical tests of the outside axial and helical flows were carried out respectively . the velocities and pressure profiles and shear distributions have been obtained and they were compared due to the different flow field . it is concluded that when no particles are deposited , the helical flow would lower the pressure on membrane surface to some little extent but not markedly ( 1 )對外軸向流和外切向流兩種方式下膜器環(huán)隙內(nèi)流場進行變參數(shù)數(shù)值實驗,作出流場及切應(yīng)力的分布規(guī)律,分析無顆粒沉積時層流條件下流動結(jié)構(gòu)對過濾通量的影響,認為:采用外旋流的方式將對膜面壓力有削弱作用,但并不明顯。