phase velocity and group velocity 中文意思是什麼
phase velocity and group velocity
解釋
相速和群速-
With any signal you can talk about two speeds called the phase velocity and the group velocity
對于任何信號都有兩個速度即相速度和群速度。 -
The research results are controlled source which has linear or nonlinear variabe frequency scan function and the seismic instruments which match with it, and the method of small group intervals, small offset, much more channels, short array length, high - frequency receivers are applied during the link of data acquisition, and that the techniques of the refraction static correction, the noise suppressing, the high - resolution velocity analysis, the wavelet length compression, the wavelet zero - phase, and the prestack migration should be applied emphasizedly during the link of data processing and interpretation
研究表明，對于城市活斷層的抗干擾高解析度淺層地震勘探，在數據採集環節應採用具有線性或非線性變頻掃描功能的可控震源和與其相匹配的地震儀器，以及小道間距、小偏移距、多接收道、短排列和高頻檢波器接收的工作方法；在數據處理與解釋環節，要重視折射靜校正技術、噪聲壓制技術、高精度速度分析技術、子波壓縮技術、子波零相位化技術和疊前偏移技術等的應用。 -
The origin of supercontinuum ( sc ) generation in optical fibers has been conjectured to be the interplay between fiber nonlinearities ( self phase modulation, cross phase modulation and raman self scattering ) and group - velocity dispersion ( gvd )
光纖中超連續supercontinuum （ sc ）譜的產生源於光纖中各種非線性效應（自相位調制效應、交叉相位調制效應，四波混頻效應及受激raman散射等）和群速度色散的共同作用。 -
Based on these foundations, we give a perfect scheme of the bbo opos : single pass amplification coefficient of the opg under different pump intensity is calculated ; collinear type - i and type - ii phase matching tuning curve pumped by the q switch nd : yag various harmonics as well as noncollinear type - i tuning curve are calculated in details ; the effect of the walkoff for the nonlinear effect coefficient and the group velocity matching are analyzed ; the acceptance angle in parametric process is calculated ; the numerical threshold of the bbo opo is calculated ; the process of the saturation and depletion of the pump beam are analyzed ; the relationship of the conversion efficiency and reflectance of output mirror are discussed ; various linewidth controlling methods are discussed ; the improvement of the beam quality applying the unstable cavity is discussed ; and the crystal bbo design is considered
在此基礎上，給出了一整套bbo - opo激光參數設計方案：計算了不同泵浦強度下的參量放大倍數；詳細計算了在nd : yag調q激光器各次諧波泵浦條件下的共線類和類相位匹配的調諧曲線，以及非共線類相位匹配調諧曲線；分析了走離角對非線性系數和群速匹配的影響；計算了參量過程的允許角；計算了bbo - opo的理論閾值條件；分析了飽和與泵浦光束的消耗過程；給出了轉換效率與超過泵浦閾值的倍數的關系；討論了轉換效率與輸出鏡反射率的關系；討論了線寬控制的各種方法；研究了利用非穩腔改善光束質量的方法；考慮了bbo晶體的設計。 -
The phase matching and group velocity matching conditions of type - i and type - ii second harmonic generation ( shg ) are obtained according to the momentum and energy conservation laws. the group velocity delay of ultrashort pulse shg on clbo and the crystal length decided by the group velocity delay are analyzed and compared with bbo ' s
從動量守恆、能量守恆出發推導得出了超短脈沖倍頻的類、類相位匹配和群速匹配條件，對clbo晶體用於超短脈沖倍頻時的群速延遲以及由群速延遲決定的晶體長度進行了分析和數值模擬，並與bbo晶體進行了比較。 -
We derive an analytic expression of the group velocity dispersion ( gvd ) induced chirp and the self - phase modulation ( spm ) induced chirp in the normal dispersionregion of non - kerr - like optical fibers with saturable nonlinarity. the evolution of chirp is simulated by numerical methods. the studied results show that the more powerful saturable effects, the smaller is chirp and the gently is chirp. the net chirp is zero in the central region of the pulse
從理論上推導出具有飽和非線性的非克爾光纖正常色散區內，群速度色散效應導致的啁啾和自相位調制效應導致的啁啾解析表達式.利用數值解法模擬了非克爾光纖正常色散區啁啾演變過程.研究結果表明：當非克爾光纖的飽和非線性增強時，凈啁啾不斷減小，而且，越來越平緩，脈沖中心附近區域凈啁啾接近零 -
On the following, on the basis of formulas given above, three kinds of effects due to ionosphere are presented : image shift due to group delay which was caused by the difference between the group velocity and the velocity of light in the ionosphere ; image distortion due to ionospheric dispersion which can create second phase error of lfm signals ; the last, the phase perturbation caused by the irregularities of the ionosphere can reduce the coherent length and affect azimuthal resolution
文中主要研究了電離層的三種影響：信號經過電離層傳播的群延遲引起的成像偏移；電離層的色散效應給線性調頻信號帶來二次相位誤差，導致圖像退化、失真；以及電離層的閃爍、湍流等不規則性引起的信號相位起伏。在此基礎上，比較分析了不同波段、帶寬條件下電離層的影響。 -
The effect of pump beam ' s walk - off and the group - velocity - mismatch in bbo crystal is discussed, the group - velocity - mismatch can be compensated by non - collinear phase - match when the angle between signal and idler beams equals to 14. 4
當下轉換光與抽運光夾角達到13 . 4度時，非共線相位匹配基本可以消除晶體中群速失配對下轉換過程的影響。 -
The origin of supercontinuum spectrum ( sc ) generation in optical fibers has been shown to be the interplay between fiber nonlinear effects ( such as self phase modulation, cross phase modulation, stimulated raman scattering and stimulated brillouin scattering etc ) and group - velocity dispersion ( gvd )
光纖中超連續譜supercontinuumspectrum （ sc ）的產生源於光纖中各種非線性效應（如自相位調制效應、交叉相位調制效應，四波混頻效應、受激raman散射與受激brillouin散射等）和群速度色散共同作用。 -
The features of phase and group velocity were advanced by means of preparing samples with different shaping. the phenomenon of " cusp " in group surface of quasi - shear wave ( qsv ) was observed. the inversed velocity surface according to calculated elastic constants in real orthotropic media is consistent with practical measured velocity surface
用加工不同樣品形態的方法給出了正交各向異性介質的相速度和群速度特徵，觀測到各向異性介質群速度面上的尖點現象，並用測試得到的正交介質的彈性常數進行了數學模擬，其波場特徵與測試的速度面特徵相符。 -
The dispersive characteristic of sws is a very important parameter of the rbwo and rtwt, other parameters such as the phase velocity, group velocity, coupling impedance can be derived from the linear dispersion relation. recently, the photonic crystal have attracted many attentions of the scientists, which has become a hot point of the research, it is also a ps
周期慢波結構色散特性是研究高功率微波器件的一個重要參量，其他重要特性如相速、群速、耦合阻抗等參量都可以從色散關系衍生出來，準確，快速獲得周期電磁結構的色散特性就顯得尤為重要。 -
The accurately controlled signal source generates sinusoidal elastic wave accurately controlled in frequency and stable in phase to " illustrate " underground media. time signal stacker receive signal by stacking and doing fft to measure the transfer function of media. " sompi " cepstrum method retrieve group velocity travel times and decayed factors of wave element from observational data of transfer function in a limited frequency window
精密可控震源用於產生頻率精確相位穩定的正弦彈性波以照射地層內部，信號疊加器通過對接收信號進行疊加和進行傅立葉變換的方式實現對介質傳遞函數的精密測量， 「存否」倒譜方法能夠根據一段窄帶頻域傳遞函數數據獲得時域上各個波成分的群速度傳播時間和介質衰減因子。
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