頻率方向譜 的英文怎麼說
中文拼音 [bīnlǜfāngxiàngpǔ]
頻率方向譜
英文
frequency-direction spectrum- 頻 : Ⅰ形容詞(次數多) frequent Ⅱ副詞(屢次) frequently; repeatedly Ⅲ名詞1 [物理學] (物體每秒鐘振動...
- 率 : 率名詞(比值) rate; ratio; proportion
- 方 : Ⅰ名詞1 (方形; 方體) square 2 [數學] (乘方) involution; power 3 (方向) direction 4 (方面) ...
- 譜 : Ⅰ名詞[書面語]1 (按類別或系統編成的書或冊子等) table; chart; register 2 (指導練習的格式或圖形)...
- 頻率 : frequency; rate
- 方向 : direction; orientation
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The experimental results show : the flattop phenomenon on the diode voltage pulse was very apparent for using the carbon fiber cathode, that is to say, the pulse duration of the diode voltage was widened ; moreover, under the condition of the same power of microwave, the pulse duration of the out - put microwave was prolonged by about 30 % ; the peak power of the microwave was enhanced by 3db
通過在裝置上做的兩種陰極的對比實驗,結果顯示:碳纖維陰極的使用,改善了電子束質量,使輻射微波的脈寬增加了30 %以上,輻射主瓣方向上的功率密度提高了3db以上,頻譜分佈較純凈,實現了微波的高效輸出。In the study of directional spectrum and reflection coefficient of multidirectional wave, firstly the wave elevation trains overlapped by the incident wave and the reflected wave of multidirectional wave are simulated in the method of a frequency corresponding to a direction. then the composed wave trains are analyzed respectively by the mbdm and the mmlm. during the numerical study, the input factors include the various wave parameters, the different measuring wave system and the various reflect characteristic
在多向不規則波入射波方向譜和反射系數的分析研究中,利用方向頻率對應法模擬了多向不規則波入射波與反射波疊加的波面序列,將此合成波列分別應用mbdm和mmlm進行分析,通過輸入各種波浪參量、不同波浪測量系統和各種反射特性等因子,檢驗了mbdm和mmlm方法的適用條件,對兩種分析方法的性能進行了比較分析。A cyclic radial shearing interferometer was used to diagnose the wavefront distortion of a laser system and an lcslm ( liquid crysnd spatial ligh modulator ) was used to control it. some results have been summarized as follows : l. according to the theory of scalar quanity diffeaction and the model of the random gaussian phase screen of low frequency wavefront, the effect of the low frequency wavefront with different rms gradient on the focal spot of a laser beam was studied
本論文在激光光束波前畸變檢測和控制上進行了新的探索,主要就空間相位調制環路徑向剪切干涉儀以及它對波前畸變的檢測和液晶空間光調制器及其對中頻段波前畸變的控制進行了研究,其研究的內容和取得的成果如下:一、根據標量衍射理論,結合低頻波前畸變的高斯隨機位相分佈模型,研究了不同均方根梯度低頻畸變波前對激光光束焦斑聚焦性的影響,並採用描述中頻段波前畸變的功率譜密度概念,模擬計算了它對激光焦斑旁瓣的貢獻。All - solid - state laser is an advantage lamp - house. it has many important applications and potential commercial value in many fields, such as industry, scientific research, military. so it ' s always the research focus of laser field. diode end - pumped solid - state laser has many merits. including high efficiency, long lifetime, high frequency stability, narrow line width, compact configuration, convenient for use et al, which made her a necessity in many high level quantum optics experiments. in this thesis, a series of experiment research was done with regard to blue laser, green laser and infrared laser
激光二極體端面泵浦的固體激光器具有效率高、譜線窄、壽命長、結構簡單、使用方便等優點,特別是採用環行諧振腔內加光學單向器構成的單頻激光器,由於頻率穩定,使其成為許多高水平量子光學實驗的主要光源。本論文圍繞全固態單頻藍,綠,紅外激光器進行了一系列實驗研究工作。In the analysis of the frequent spectrum and the reflection coefficients, based on goda ' s two - points method which fit to the normal incident wave, a modified two - points method is derived that can be used to calculate the frequent spectrum and reflection coefficient of the oblique waves from which the frequent spectra of incident waves and reflected waves incoming in arbitrary angular, the bulk reflection coefficient and the frequent spectrum of reflection coefficient could be computed, also from which in theory the waves could be measured in two wave gauges which is disposed at any direction
為了分析單向不規則波入射波的頻率譜和反射系數,本文在goda用於分析正向不規則波的兩點法的基礎上,提出了可用於斜向不規則波頻譜分離及其反射系數計算的改進兩點法,該方法可用於計算任意波浪入射角的入、反射波譜、總體反射系數和反射系數的頻率譜,並且測量波浪過程的兩浪高儀可在較廣的方向范圍內布置。The frequency analysis results show conclusions as follows : 1. the relative valid spectral power is declined with the volume percentage of inclusions in terms of exponent curve and the tendency of negative direction is same to that of forward direction
當ly12鋁合金細小夾雜物(小於0 . 16mm )的體積百分數從0 0 . 35時,在35 50mhz的頻帶范圍內,超聲波形的有效譜功率按近似指數曲線快速下降,沿相反方向檢測時其變換趨勢相同。None but is the test spectrum abundant and controllable, it is possible to simulate the stresses environment needed for exposing weakness of the product. based on summarizing the present status of the vibration test and vibration environment simulation technology in the world, the topic of simulation of super - gaussian random vibration environment with controllable frequency spectrum and its applications in reliability enhancement testing is put forward. the main content and conclusions of the dissertation are as following : 1
本文在綜述國內外振動試驗技術和振動環境模擬技術的基礎上,引出「頻譜可控的超高斯隨機振動環境模擬技術及其在可靠性強化試驗中的應用」這一主題,並緊緊圍繞該主題開展了如下研究工作: 1 .全面分析了振動激勵的功率譜密度量級、幅值分佈、帶寬以及試件結構的固有頻率、阻尼比等因素對疲勞損傷累積的強化效應,提出振動強化試驗激勵信號應具備的重要特性:頻譜可控和超高斯,確立了本文的研究主題和方向。Secondly, basing on the theory of on - off gain of small signal, the raman gain coefficient for frequency shift between 0. 5 and 20 thz of standard sigle mode optical fiber is measured by pump - probe method through a super luminescent diode ( sld ) as a broadband small signal probe source. thirdly, numerical simulation analysis of gain characteristic of raman fiber amplifier for c band wdm signal light is made according to the raman gain coefficient of the fiber measured before through target and four rank runge - kutta method. at the invariability of wavelength and maximum power of each of two pumps, schematic of powers of two pumps for best flatness on c band wdm optical gain was found out, at the same time, the factors of resulting in gain saturation is analyzed, too
本文首先應用經典的電磁理論對拉曼光纖放大器的工作機制進行了分析,然後,根據小信號理論推導出的開關增益求出了光纖拉曼增益系數的表達式,採用泵浦-探測波的方法,利用超輻射激光二極體( superluminescentdiode簡稱sld )作為探測光源,測量了所用標準單模光纖頻移為0 . 5 - 20thz的拉曼增益系數,之後根據所測得的光纖的拉曼增益系數譜對應用該類光纖構成的放大c波段wdm光信號的拉曼光纖放大器的增益特性採用打靶法和四階龍格- - -庫塔進行了數值計算,在給定了兩個泵浦光源的波長和最大功率后,找出了反向泵浦情況下使c波段wdm光源增益最平坦的兩個泵浦的各自最佳功率,同時也分析了導致信號光飽和的原因。Testing the vibration acceleration signal of rail top ( lateral and vertical ), rail middle ( lateral ), rail bed side ( vertical ) and rail bed middle ( vertical ) with dasp vibration testing system, calculation of signals obtains the power spectral density and frequency response curves of different position
測試橫向和垂向激振力下鋼軌不同部位的振動信號,進行頻譜分析,得出不同部位的頻率響應曲線。通過對頻響曲線的分析,得出不同方向激振力下鋼軌振動能量集中的頻率,確定不同方向激振力下鋼軌的主要振動部位和振動形式。Based on fourth - order cumulant, a computationally efficient method for joint estimating both directions of arrival and ranges of near field sources with known carrier frequency is firstly presented. the proposed algorithm need not any spectral peak searching and the 2 - d parameters are automatically paired. lt is suitable for arbitrary additive gaussian noise environment. in the following section, a 3 - d esprit method for jointly estimating of frequencies, doa ' s and ranges of multiple near - field sources with unknown carrier frequencies is proposed. the parameters estimation are given by the eigenvalues of different matrices. furthermore, its performances are confirmed by several computer simulations
利用四階累積量,第五章首先給出了一種載頻已知的情況下基於近場源的距離和波達方向聯合估計演算法,通過構造的陣列輸出信號四階累量矩陣使空間信號到達方向和距離估計無需譜峰搜索,且參數自動配對,適合於任意高斯噪聲環境。進一步在第三節提出了一種載頻未知的情況下的多個近場窄帶信號源doa 、距離和頻率聯合估計的3 - desprit演算法。This paper presents that the directional spectra and the reflection coefficients of the oblique and the multidirectional irregular waves on the co - exist wave field of incident wave and reflected wave have been studied. a modified two - points method is proposed that can be used to calculate the frequent spectrum and reflection coefficient of the oblique waves. for the multidirectional irregular waves, the directional spectra and reflection coefficients are obtained by the modified bayesian directional method and the modified maximum likelihood method
本文研究了入、反射波共存場中斜向不規則波和多向不規則波波浪場的方向譜和反射系數,對于斜向不規則波頻率譜及反射系數的計算提出了一種改進兩點法( mtpm ) ,對于多向不規則波方向譜和反射系數的分析,應用了改進的貝葉斯方法( mbdm )和改進的最大似然法( mmlm ) 。Testing datas are gathered by using data picking box cras. a general dynamic model for analyzing characters of vibration system has also been developed according to the input and output applied on the testing system. identifications for structure modal parameters and frequency - spectrum characters have been carried out by calling the interface software developed unpon matlab software in both the time field and the frequency field. the structure modal parameters and frequency - spectrum characters have been accurately calculated
利用cras數據採集箱的數據採集功能對系統的信號進行數據採集,通過介面軟體調用matlab軟體平臺,分別針對時間域和頻率域兩種研究方向,解決振動系統模態參數的辯識問題和結構的頻譜特性分析問題,得到系統的相干函數等頻譜特性,獲得模態參數,如模態頻率、阻尼等的精確解。After the systemic comparison of the two methods, the detail applicable conditions have been suggested. by the physical model tests and various methods, the frequent spectrum and the directional spectrum of incident waves and reflected waves of slope breakwater have been investigated systemically, and the bulk reflection coefficients, the directional spreading of reflection coefficients and the frequent spect
通過物理模型試驗,系統地研究了斜坡堤前入、反射波方向譜的分離計算,採用mtpm分析得到了單向(包括斜向)不規則波的總體反射系數和反射系數頻率譜(隨堤坡變化)以及由iribarren數表示的包含堤坡影響的反射系數頻率譜。2. methods in frequency domain : through a comparative study, wedge and ring feature of fourier transform performs better than other features based on texture spectrum. it represents the directivity, coarseness and regularity of an image
在基於頻率域的紋理分析方法中,分析了基於傅立葉變換的紋理分析方法,經兩組對比實驗,楔環特徵能夠很好的反映圖象紋理的方向性、粗糙性和規律性,在檢索中明顯優于基於頻譜的簡單統計特徵。分享友人