查询词典 difference frequency

In conventional seismic data processing, the earth is regarded as prefectly elastic medium.However,the pores of stratum rock often contain fluid. So, when the seismic wave propagates in it, there are energy attenuation and phase distortion related to frequency. Moreover, the attenuation, scattering,and dispersion of high-frequency components are far higher than that of low-frequency components.

常规地震资料处理中把大地看成是完全弹性介质，实际上，地层岩石孔隙中常常含有流体，当地震波在其中传播时要发生与频率相关的能量衰减和相位畸变，且高频成分的衰减、散射和弥散远高于低频成分。

In contrast, the frequency-domain method transforms the time-frequency convolution into product operation in multiple frequency bands, thus has simple com putation and fast speed. As such, it has become a mainstream method for blind deconvolution.

相比之下，频域方法将时频卷积变换为多个频率段上的乘法运算，运算简单，速度快，因此成为盲解卷的主流方法。

This paper introduces eight methods of tlme-frequency analysis, such as Hilbert transform, Hilbert-Huang transform, sine curve fitting, Ricker wavelet matching, short time Fourier transform, wavelet transform, S transform and Cohen methods, This paper explains the merits and defects of those methods from the time resolution, frequency resolution and the adaptive ability of multi-frequency signals.

本文介绍了Hilbert变换、Hilbert—Huang变换、正弦曲线拟合、雷克子波匹配、短时傅立叶变换、小波变换、S变换以及Cohen娄这八种方法，并从时间分辨率、频率分辨率，以及对多频率成份信号适应能力等各方面阐述了各种方法的优缺点，对其中的一些方法结合了理论记录进行了试算，进一步阐述了这些方法的长处和不足之处。

Ricker wavelet whose predominant frequency is 200Hz was chosen as the exciting wave, and the character parameters (predominant amplitude, predominant frequency and frequency bandwidth) of its reflected wave were calculated.

选择主频为200Hz的雷克子波，理论计算原始地震反射波的特征参数（主振幅、主频率、频带宽度）。

We select the weighting matrices in the frequency domain, and then design the controller in the state space. The cases that the plants consist of both low-frequency parameter perturbations and high-frequency unmodelled dynamics have also been considered.

文中考虑一大类存在低频摄动和高频未建模动态的情形，给出了鲁棒控制设计中兼顾闭环动态特性和干扰抑制时的加权阵选择方法与具体步骤。

As the same section is concerned, near the bottom the maximum value of frequency appear within 1mm of bubble size, towards the water face this value tend to decrease, yet the corresponding size turns to increase; in the same time, the frequency is concentrated near the bottom and deconcentrated near the water face; under the experiment condition, the maximum frequency of the total section approximately appear at 0.5mm size; mean bubble size access 0 at bottom and increase acceleratively towards water face where tend to be infinite; total number increase during developing of aeration, and become steady when reach wholly developed area; on the same section, the total number in unit time tend to increase at first and decrease then, along the water depth.

对于同一断面，靠近槽底的测点气泡个数分布最大值出现在气泡尺寸小于1mm的范围内，朝水面方向各测点气泡个数分布最大值呈减小趋势，而其对应尺寸则呈现变大趋势；在靠近槽底，个数分布表现得比较集中，而在水面附近气泡个数分布曲线表现得低而平缓；实验条件下，整个断面上的气泡个数分布的最大值大体上出现在尺寸为0.5mm的地方；气泡平均尺寸在槽底处接近于0而朝水面方向迅速增大，且越接近掺气水流的水面，增加速度越快，最终趋于无穷大；气泡总数在掺气发展区内是沿程增加的，当掺气水流发展到一定程度后气泡总数就基本保持不变了；在同一断面上，各测点单位时间内的气泡总数随高度呈现出先增加后减小的趋势。

Demodulates the FM modulated signal Y at the carrier frequency Fc. Y and Fc have sample frequency Fs. FREQDEV is the frequency deviation of the modulated signal.

Josephus 问题的解答。n个孩子围成圆圈，选任一个数m，从第一个孩子开始数，数到m停止，这个孩子离开，再从第一个开始数，直到剩下一个孩子。

The study about the flux and index of gamma-ray loud blazars show:(1)there is significant correlation between the luminosities in gamma-ray and VLBI radio energy band;(2)there are strong anticorrelarions among the observed indices of soft X-ray, hard X-ray and gamma-ray. For the FSRQs, the whole X-ray emission was contributed by synchrotron self-Compton emission, for the HBLs, the X-ray emission was dominated by synchrotron emission while the soft X-ray emission is dominated by synchrotron emission and the SSC emission dominate the hard X-ray energy band for LBLs;(3) there are strong radio-radio and radio-optical flux correlations for the quasar 3C 273. The higher frequency emission leads those in lower frequency. The multi-band complex indices strongly correlated with the high frequency flux which implies that the object is becoming bright when the energy spectrum is harden.

通过对γ噪Blazar天体的谱指数、流量的相关研究，发现（1）51个样本blazar的γ射线光度与VLBI光度之间存在显著相关；（2）软X、硬X以及γ波段的观测谱指数之间存在较强的反相关，对FSRQs，无论是硬X射线还是软X射线的辐射都是逆康普顿辐射的贡献，而对于HBLs来说，则是同步辐射的贡献，对LBLs，在软X射线波段以同步辐射贡献为主，在硬X射线能区以逆康普顿贡献为主；（3）3C 273的射电各个波段以及光学之间存在强相关，高频辐射一直领先低频辐射，3C 273的多波段复合谱指数和高频流量之间存在强的反相关，意味着当能谱变硬时对象变亮。

The FEM, whose process is very *** and is fit to deal with complex boundary condition, is used to simulate the frequency-domain IP. Studying the characters and laws of IP\'parameters under different measuring devices and undulate topography will provide scientific references and basis and reduce the multiplicities of interpretation. It is will be an attempt and exploration.Because of the frequency of the exciting currents is usually between 10-2～102 Hz, the vector A can be seen is not change with the time and the EM effect can be ignored in the low frequency.

双频以及伪随机三频激电法以它特有的轻便、快捷、高效率等特点在有色金属矿躲勘探领域里获得了广泛的应用，运用有限单元法的推导过程简单、适合处理复杂几何外形等特点来对双频以及伪随机三频激电法进行正演数值模拟，分析和研究了激电参数在不同丈量装置、模型参数和起伏地形情况下的特点和规律，为后续的资料解释提供科学的依据和参考，为减少地球物理中的多解性做一些有益的探索和尝试。

At first, setting up the arith relation between the signal input and the signal output of the generalized multi-carrier system of the Discrete Fourier Test spread-spectrum; then setting equilibria parameters of the frequency field equilibria subcarrier of the generalized multi-carrier system of the DFT spread-spectrum according to channel frequency response, channel noise variance and equilibria method; then calculating average power of useful signal, interferential average power between signals as well as noise variance of the generalized multi-carrier system receiving terminal of the DFT spread-spectrum according to the arith relation as well as the frequency field equilibria parameter, and recomputing available signal information noise ratio, so as to calculate the available signal information noise ratio of the generalized multi-carrier transmission system accurately, the method for estimating the available signal information noise ratio can be used for link self-adapting transmission solution of the generalized multi-carrier system based on Discrete Fourier Test spread-spectrum and radio material management.

一种DFT扩频的广义多载波系统的SINR估计方法，其通过首先建立所述离散傅立叶变换扩频的广义多载波传输系统的信号输入输出之间的数学关系，然后根据信道频率响应、信道噪声方差和均衡方法，设定所述DFT扩频的广义多载波传输系统的频域均衡子载波的均衡系数，再根据所述数学关系及所述频域均衡系数分别计算所述DFT扩频的广义多载波传输系统接收端有用信号的平均功率、信号间干扰的平均功率以及噪声方差，再计算有效信干噪比，如此以实现对广义多载波传输系统的有效信干噪比的准确计算，该有效信干噪比估计方法可用于基于离散傅立叶变换扩频的广义多载波传输系统的链路自适应传输方案和无线资源管理方面。

Chimborazo and Cotopaxi, took me by the hand.

越过琴博腊索山和科托帕克西山。

This car is in a good condition.

这辆车的状况很好。