衰減平段 的英文怎麼說
中文拼音 [shuāijiǎnpíngduàn]
衰減平段
英文
segment,attenuated flat-
Experiment contrast show, the prepared w - type planar hexaferrite microwave absorptive material appears two absorptive peaks in the frequency range of ( 7 ~ l2ghz ), its average attel1uation exceed 7db, the maximum absorptive attenuation is 24db, coat matching thickness is l. 21mm, especialy its curie temperature is 457c. so, it can meet practical demands in military camouflage field
實驗結果表明，該種吸收材料在x波段內呈現兩個吸收峰，平均衰減量7db ，最大吸收峰為24db ，塗層匹配厚度為1 . 21mm ，特別是具有457的居里溫度。所以該種鐵氧體是一種性能優良的微波吸收材料，在軍事隱形技術中有實用價值。It is shown by structural seismic response of four wavelets that littlewood - paley wavelet is not suitable for structural seismic response, because structural response is too small, meyer wavelet is a better wavelet for structural seismic response, for it ' s structural response is agreement with the finite element method, and also harmonic wavelet, structural response under earthquake is a little bigger than finite element method, structural response under odd exponent wavelet is also bigger than finite element method, this method is very simple by wavelet transform, wavelet transform method is different from old methods, one is with which not only knows the effects of earthquake wave detail frequency - band on structural response, but also considers earthquake wave ' s non - stationary of frequency and time - domain value, another is the second mode shape and higher mode shape response that do n ' t attenuate so fast
通過對這四種小波的結構地震反應分析研究說明： littlewood ? paley小波不適合於用來作結構地震反應分析，因為在littlewood ? paley小波下的結構地震反應太小，不符合實際情況；用meyer小波作結構地震反應分析比較合適，和有限元法的結果比較接近；也可以用諧波小波來作結構地震反應分析，只是在諧波小波下的結果略為偏大；單邊指數小波下的結構地震反應分析比有限元法稍大一點，它通過小波變換大大簡化了結構地震反應分析。用小波變換方法來進行結構地震反應分析和以往方法不同的是：它不僅可以知道地震波的具體頻率段對結構反應的影響，而且同時考慮了地震波的幅值非平穩性以及頻率非平穩性；另外與以前方法得到的結果有差異的是，第二振型及以後的高一點的振型的反應沒有以前的方法衰減得快。A natural sounding headphone should have a gentle hump in the bass ( about 3 or 4 db ) between 40hz and 500hz. ( this compensates for the fact that headphones don ' t give you the physical punch that the sound from a speaker has ; so a slight compensation of increased bass is needed for natural sound. ) headphones also need to be rolled off in the highs to compensate for the drivers being so close to the ear ; a gently sloping flat line from 1khz to about 8 - 10db down at 20khz is about right
這大致是說，耳機頻響曲線在低頻40 - 500赫茲間有個小的隆起是正常的，因為耳機不能象喇叭那樣給人真實的低頻沖擊力，所以在這個低頻段加強一些，聲音反而自然逼真些.另外，為避免太刺激耳朵，耳機在1000赫茲起到耳朵聽力的極限20000赫茲間應該有衰減，到2萬赫茲處比平均輸出低8 - 10分貝是正常現象
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