attenuation
US /əˌtenjʊ'eɪʃn/
・UK /əˌtenjʊ'eɪʃn/
C2 高級
n. (u.)不可數名詞變薄 ； 稀薄化 ； 弄細 ； 衰減
The industrial district had to undergo an attenuation of background noise for worker comfort
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3.8 菲涅爾方程 (3.8 Fresnel Equations)
23:07
- We're going to be talking about the reflection and The refraction of waves when they hit an interface otherwise known as Fresnel equations if you're following along in my book What we're covering is in chapter 8 and since we're going to cover a whole chapter I'm just going to give you the highlights and not give you the derivation Although the derivations of Fresnel's equations is a really good way to understand if you you really know waves or not So if you remember in our picture We essentially had an incoming electric field and that electric field would turn on and off and it would essentially Jiggle the clouds of the atom the electron clouds of the atoms up and down and we saw that this can lead both to change in the phase constant with distance the index of refraction or the relative permittivity of the material and also some absorption or some loss and If you have a material where you have some absorption and I'm going to say it's three here and a phase constant Which is three and this is the equation that describes our plane wave going into the material and I'll note that the plane wave is Here at normal incidence that essentially in the general case You're going to get a change of the wavelength of the material that arises from a change in the velocity phase velocity and you're also going to get some kind of exponential type of attenuation as the wave goes down into the material and You can calculate the absorption coefficient alpha Which is the attenuation of the wave with distance as well as the spatial phase change of the wave Using some expressions as we saw before and these are the most complicated expressions.
我們要討論的是波碰到界面時的反射和折射 也就是所謂的菲涅爾方程 如果你在看我的書的話 我們要討論的是第8章的內容如果你還記得我們的圖片 我們基本上有一個進入的電場 電場的開啟和關閉 基本上會使原子雲 原子的電子雲上下襬動如果你有一種材料，它有一定的吸收，我假設它的吸收率是3，相位常數是3，這就是描述我們的平面波進入材料的方程式。你可以計算吸收係數α，即波隨距離的衰減以及波的空間相位變化。
聽聽最好的 ANC 耳機如何應對真實世界和實驗室測試 (Hear how the best ANC headphones handle real world and lab tests)
12:51
- It doesn't work as well at higher frequencies, but a well-designed ear cup can block a lot of this through passive attenuation, just plugging your ears, basically.
雖然在高頻率下效果不佳，但設計精良的耳罩可以通過被動衰減（基本上就是堵住耳朵）阻擋大量的高頻率。
- Look at how good Sony's ear cups are at just passive attenuation.
看看索尼的耳罩在被動衰減方面有多出色。
**驚爆全場！伊隆馬斯克震撼現身世界經濟論壇達沃斯，火力全開接受提問！** (FULL EVENT: Elon Musk Takes Questions In Shock Appearance At The World Economic Forum In Davos)
31:59
- And you get about 30% more power in space because you don't have atmospheric attenuation of the power.
而且你在太空中能獲得大約 30% 的額外電力，因為沒有大氣衰減。
高志強 - WikiVidi紀錄片 (CHARLES K. KAO - WikiVidi Documentary)
15:30
- Initially Kao worked in the team of Antoni E. Karbowiak, who was working under Alec Reeves to study optical waveguides for communications. Kao's task was to investigate fibre attenuation,
- Kao with Hockham concluded that the fundamental limitation for glass light attenuation is below 20 dB/km, which is a key threshold value for optical communications. However, at the time of this determination,
