波數差 的英文怎麼說
中文拼音 [bōshǔchā]
波數差
英文
wave-number difference-
While the budgeted figure may be reasonable as an average over a longish period, it is bound to be different from the actual out - turn, possibly quite significantly given financial market volatility
雖然以長期平均數來衡量，預算數字是合理的，但它與實際結果肯定每年都會有出入，而且由於金融市場波動，差別更可能會相當顯著。In this paper, high - order accurate weighted essentially non - oscillatory ( weno ) schemes are investigated and their applications in hyperbolic conservation laws are discussed. based on this, a new weno difference scheme which based on dispersion - relation - preserving relation is developed, and representative test cases with this scheme for computational aeroacoustics ( caa ) problems has been implemented and compared in order to test capability of wave capturing ; in addition, weno schemes generally do not converge at high order in the presence of contact discontinuity of euler equations, so a conservative front tracking technique coupling weno schemes and level set method to simulate the translating density profile is presented here, and numerical simulation with this technique for representative test case has been implemented and results show the desired accuracy
本文研究了高階精度加權基本無振蕩（ weno ）格式及其在雙曲守恆律方程中的應用，在此基礎上作了兩個方面的工作：一是針對高頻聲波問題構造出一種基於保色散關系（ drp ）的weno有限差分格式，並對計算氣動聲學（ caa ）問題的代表性算例進行了大量數值實驗，比較了該格式捕捉波數的能力；另外，針對高階weno格式在處理euler方程的接觸間斷時精度有所降低的問題，研究了利用界面追蹤技術levelset方法和高階激波捕捉weno格式相結合的一種守恆追蹤方法，並且給出有代表性的密度滑移面問題的算例，得到一致高階精度的數值模擬結果。1. assuming prismatic cross - section in the direction of the track, when the difference of the characteristic of soil along track is slight, and then processing expansion in wavenumbers along this direction
為此，本文主要研究了以下幾個方面： 1 、在考慮軌道方向上地基土性質差別不大的前提下，取列車移動方向為相同的截面，並沿這個方向進行波數展開。Three finite - difference methods, i. e., stagger grid, implicit and explicit algorithms, are analyzed in detail. multi - grid algorithm is firstly introduced in elastic wave simulation, to solve for the stability problem inherent in stagger grid and implicit algorithm, also for the efficiency problem inherent in explicit algorithm, and the precision, stability and efficiency for simulation of elastic wave arc increased by multi - grid method. phase - delay method is provided to effectively absorb boundary reflection and increase efficiency for wave motion simulation, based on phase delay and amplitude decaying features along wave propagation
在水平分層介質接收函數的波形反演研究的基礎上，本文系統闡述了非均勻介質中彈性波傳播數值模擬常用的三種有限差分方法：顯式差分、隱式差分和交錯網格法，首次將多重網格演算法應用於彈性波方程的數值模擬問題，克服了交錯網格法和顯式差分法穩定性差，以及隱式差分法計算效率低的缺點，大大提高了彈性波數值模擬的精度、穩定性和計算效率。In this dissertation, the numerical computation for the acoustic radiation problem ( arp ) is studied deeply and systematically in the theory, method and the application technique, based on analyzing the situation of the home and abroad on the numerical computation for the acoustic radiation problem. the calculation formulas of the boundary element method ( bem ) for the exterior acoustic radiation problem in the full - space and half - space are deduced, based on the wave propagation theorem ; the arising of the non - unique solutions, which is associated with the application of the boundary integral equation ( bie ) in acoustic radiation problem, is analyzed and proofed ; the improved combined helmholtz integral equation formulation ( ichief ) is presented to overcome the non - uniqueness problem more effectively and reliably ; the determination of the singular integral coefficients on various occasions is analyzed ; the properties and treatments of the singular integrals with different orders axe studied ; the computation program of the cubic spline ichief is developed and its ability to overcome the non - uniqueness problem and feasibility to discrete the surface coarsely with the sufficient calculation precision are examined through examples
第二章在聲波動理論基礎上，詳細地推導出對應于無限域和半無限域的外部振動聲輻射問題的邊界積分方程計算公式；根據fredholm積分理論，對利用邊界積分方程計算振動聲輻射問題過程中解的非唯一性的產生進行了分析和證明；改進了chief法以提高其克服解的非唯一性的有效性和可靠性；對不同條件下奇性系數的計算、強奇性積分的收斂性及其在變量替換時與普通積分的差異性、不同階奇性積分的計算、數值求積分等進行了研究；開發了三次樣條改進chief法計算軟體，並通過算例考核了該方法在特徵波數處克服解的非唯一性的有效性和在保證計算精度的前提下實現剖分粗化以提高計算效率的可行性。This conversion is based on the analytic expression of sonic and elastic wave equation, and use the different wave field extrapolation, which is initially used in seismic migration and forward modeling. this paper introduces the easy and efficient finite - difference method to realize the conversion by comparing three different methods
論文經過對三種常規波場延拓方法（ kirchhoff積分法、頻率波數域法和有限差分法）優缺點的比較，採用了簡單易用的有限差分方法來實現這種轉換。Secondly, we bring statistic coding, prediction coding, transform coding and analysis & synthesis coding into radar area. according to the properties of radar data, we take 4 methods, which are huffman coding ; prediction error model and lzw coding ; fft, uniform quantization in each frequency bank and huffman coding ; wavelet transform, uniform quantization in each frequency bank and lzw coding, to compress the genuine ground clutter radar data and give the corresponding results
根據雷達回波的特性，分別採用了huffman編碼法，預測誤差模型和lzw編碼法， fft 、分頻帶均勻量化和huffman編碼的壓縮演算法，小波變換、子帶均勻量化和lzw編碼的壓縮演算法等四種演算法，並給出了用這些演算法對真實的地雜波雷達回波數據進行壓縮的實驗結果。The numerical modeling of 3 - d elastic wave equation using a high - order, staggered - grid, finite difference scheme
交錯網格高階差分法三維彈性波數值模擬Knowing the bottom parameters, the influence of the mismatch of the bottom parameters for the inverted water sound speed and the relationship of the statistical distribution between bottom parameters errors and inverted water sound speed errors are studied using modal wave number tomography scheme
應用簡正波波數層析方法，在海底參數已知的條件下，研究了海底參數失配對反演的水體聲速的影響，以及海底參數誤差分佈與反演的水體聲速誤差分佈的關系。In this scheme digital demodulator is used to detect ifog ' s signal, digital phase ramp modulator is used as feedback controlling and digital filter is used to limit noise and lower the bits of a / d ? d / a converters
閉環方案中，採用數字解調方案進行信號檢測，採用數字相位階梯波調制技術進行反饋控制，採用數字濾波、數值濾波降低噪聲和消除a / d 、 d / a轉換死區誤差。Through the i 、 q component of ipix radar sea clutter data " s histogram analyses and by skewness and kurtosis computed, it is been shown that sea clutter amplitude is not rayleigh distribution ; through the comparison of amplitude histogram and distributed models with the same parameters, it is been shown that hh polarization clutter is lognormal distribution, whereas vv polarization is k - distribution ; at the same time the correlation function and power spectrum density are been analyzed, at last the correlation compound k - distribution stochastic sequences whose covariance matrix is been given are been generated through sirp algorithm
文中先介紹了海雜波幅度的有關模型，通過對ipix雷達海雜波數據的i 、 q分量的直方圖以及傾斜度和峰度進行了分析和計算，證明了海雜波幅度不服從瑞利分佈;使用幅度直方圖和相同參數下的各種分佈模型進行比較，得出hh極化符合對數正態分佈，而vv極化服從k -分佈的結論;同時對海雜波的相關函數和功率譜進行了分析，最後使用sirp演算法產生了給定協方差矩陣的相關復合k -分佈隨機序列。Based on the basic principle of wavelet analysis, multi - resolution analysis of signal in atomic clock is made. the coefficients of wavelet transform for synthesis atomic time, which are weighed and averaged at different wavelet scales, are obtained. then according to reconstruction theorem, multi - resolution synthesis time scale can be reconstructed. since the signal of atomic clock has been analysed by multi - resolution, we can use wavelet variance at different scales to weight and average the coefficients. thus either the difference in stability of different clock or the varying characteristic of the same clock at the different scale are all considered. finaly, this method is checked by the measured data from national timing serve center of shaanxi astronomy observatory. it confirmed that this technique, which is simple and practicable, is a new method of multi - resolution. from this method, the common characteristic of different clocks can be extracted. the stability of multi - resolution synthesis atomic time scale is obviously superior to that of other methods
本文根據小波分析的基本原理，對原子鐘信號進行多解析度分解，將分解后的小波變換系數進行加權平均，得到不同小波尺度綜合原子時的加權平均小波變換系數，然後由小波變換的重構條件，反演綜合時間尺度.由於對原子鐘信號進行了小波分解，利用不同尺度的小波變換系數的小波方差進行加權平均，這樣既考慮不同原子鐘在穩定性方面的差異，又顧及同一臺原子鐘在不同小波尺度的變化特性.最後根據陜西天文臺國家授時中心的實測數據對這種方法進行了檢驗.表明這是一種全新的多解析度綜合方法，這種方法比較簡單而切實可行，它能提取各個原子鐘的共同特性，多解析度綜合時間尺度的平穩性明顯優于其他方法Then the power spectrum was programmed to satisfy the researcher " needs. and the actual use proved that the power spectrum of cerebral infarction patient was different than the normal people
為了提高儀器的性能，對于腦電波數據，還編制了功率譜計算程序並比較了腦梗塞病人和正常人功率譜的差別。In mfi, the thesis uses the bottom reflection phase shift as the cost function and the modal wave number as input data. also, it makes errors analysis by the statistical distribution between data errors and parameter errors. there are some new ideas in it
論文在使用匹配場反演方法反演海底參數中以海底反射相移曲線作為代價函數，模式波數作為輸入數據，同時利用統計分佈進行誤差分析，具有一定的新意。On the basis of fault classification, the output voltage waveforms are divided into sub - waveforms by the counts of rectifier voltage pulse waves, then the sub - waveforms are further classified by real time measurement of voltage, taken from sub - waveform sampling points ' average values and standard deviations, thus tin fruit waveforms can be described by pattern vectors
在對各種故障進行分類的基礎上提出根據整流電壓的脈波數將輸出波形分段，通過即時監測各波段電壓采樣均值和標準差，對各段電壓波形進行分類，從而將故障波形用模式向量表示。Author, secondly, starts from the approximate expandness of square root operator, perform mathematical calculations for finite difference operator in frequency - space domain, fourier finite difference operator in mixing domain ( frequency - space and frequency - wavenumber domain ) and general screen operator in mixing domain, compare and discuss their precision of their wavefield, adaptability for lateral velocity variations, computation efficiency and stability. thirdly, author, applies the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) in frequency - wavenumber domain, to the prestack and poststack forward modeling and depth migration
第二，從平方根運算元的近似展開出發對頻率?空間域的有限差分運算元、混合域（頻率?空間域；頻率?波數域）的fourier有限差分運算元、混合域的廣義屏運算元進行了推導並對其波場描述精度、對橫向變速的適應性、計算效率和穩定性進行了比較與評述。Through using for reference and demonstrating the technology of video processing system of domestic and foreign, author has put forward a set of video processing system schemes suitable for the china " s actual conditions. by using the digital technology, such as digital encode - decode, digital phase - locked, digital filter, digital image storing, the system schemes realizes tv signal noise reduction and time error elimination in real time, and makes the system be a integrated noise reduction and time based corrector really
通過借鑒和論證國內外時基校正和視頻降噪的相關技術，作者提出了一套適合於中國國情的視頻處理系統軟、硬體方案實現模擬電視的信號數字轉換以及利用數字編解碼、數字鎖相、數字濾波、數字圖像存儲等數字技術來實現電視信號實時去噪和消除時基誤差，使系統真正做到集時基校正與降噪一體化。Hydrocarbon showings is distinguished with the recognizing method of " acoustic time ", and ( half ) quantitative assessment criterion of the distinguishing parameter for hydrocarbon showing testing, which is used to evaluate hydrocarbon showing, gas testing, meantime analyses the character of gas zone distributing and effecting factor of testing production
運用「聲波時差」含氣性識別法對該區油氣顯示層進行識別，結合試氣成果擬定油氣顯示層含氣性識別參數（半）定量標準，進而對該區油氣顯示層進行評價和試氣分析，以此了解油氣層空間展布特徵和產能影響因素。This dissertation investigated the problem for simulation of sar raw signal, focusing on the terrain - echo simulation and the product of echo data. we also discussed the influences of typical errors for the point target model and got the more real echo of point target model
本文圍繞sar原始信號模擬展開研究，討論合成孔徑雷達地面回波的產生，產生回波數據，並針對點目標分析了影響回波的幾種典型誤差，得到了更為真實的點目標回波。Owing to the fact that the wavelet transformation possesses localization and implicit difference property, the suthors show that after wavelet tansformation, the fractionally differenced process and the harmonizable periodically correlated process may be changed into stationary processes
利用小波的局部性及暗含的差分性質，證明了在小波變換后，分數差分平穩過程和可調和周期相關過程是平穩的。分享友人