频率

In order to solve the problem,We proposed a simple formula for computing paraxial travel time of single-way wave operator. The formula is based on the forward and inverse transform between time-space domain to frequency-wavenumber domain and from vector field to exponential manifold. The travel time are expressed as polynomials of the horizontal offset between the two points, and the single-square-root operator in frequency-wavenumber domain are expressed as polynomials of wavenumber. Coefficients of travel time polynomials and that of single-square-root operator are related each other and calculated by Lie algebraic integrand, exponential map and the saddle-point method.

针对此，基于时间空间域到频率波数域和向量场到指数流形上的正反变换，提出了计算单程波算子旁轴走时的简便公式，将走时表示成空间变量(地面点到地下相点的水平距离)的多项式，将频率波数域单平方根算子表示成波数的多项式，运用Lie代数积分、指数映射和鞍点法将走时多项式的系数与单平方根算子的系数联系起来，运用单平方根算子的系数计算走时多项式的系数。

In order to solve the problem, We proposed a simple formula for computing paraxial travel time of single-way wave operator. The formula is based on the forward and inverse transform between time-space domain to frequency-wavenumber domain and from vector field to exponential as polynomials of wavenumber. Coefficients of travel time polynomials and that of single-square-root operator are related each other and calculated by Lie algebraic integrand, exponential map and the saddlepoint method.

针对此，基于时间空间域到频率波数域和向量场到指数流形上的正反变换，提出了计算单程波算子旁轴走时的简便公式，将走时表示成空间变量（地面点到地下相点的水平距离）的多项式，将频率波数域单平方根算子表示成波数的多项式，运用Lie代数积分、指数映射和鞍点法将走时多项式的系数与单平方根算子的系数联系起来，运用单平方根算子的系数计算走时多项式的系数。

In order to probe into the anti-friction mechanism and effectiveness of turbulent zone of flexible pipe ,extensometer with high accuracy and high-frequency response characteristics is used to study the frequency variation feature of flexible pipe s outer diameter with Reynolds number.

为探讨柔性管的紊流区域减阻效果的产生机理，采用高精度高频率响应特性的应变仪对柔性管外径随雷诺数的频率变化特性进行了研究。

With optical feedback,the modulation frequency of output intensity is proportional to the ratio of external cavity length to internal cavity length.

有光回馈时，同时改变激光频率和外腔相位，激光器输出功率波动频率正比于内、外腔长度之比。

Taking WindowsXP,Microsoft EXCEL and VBA as tools,a series of software system on hydrologic frequency analysis which integrated the ability of graph and calculation was developed.And it contained four kinds of frequency distributions:Γ-distribution,extreme value distribution,normal distribution and logarithmic normal distribution.

以Windows XP，Microsoft EXCEL和VBA为开发环境，研制了一套集绘图与计算于一体的水文频率分析软件，其中包含了常用的Γ分布、极值分布、正态分布和对数正态分布4种频率分布线型。

For a heterogeneous elastic solid consisting of two homogeneous layers, three homogeneous layers whose shear wave velocities increasing with depth, or three homogeneous layers whose interlayer has high velocity, if there are multi-mode dispersion curves, the phase velocity V〓 of the first mode will close up to the Rayleigh wave velocity of the bottom layer when frequency f→OHz, and V〓 of the first mode will close up to the Rayleigh wave velocity of the top layer when f→∞.

由多导波模式的相速度频散曲线还可知，对于二层固体介质、结构层的横波速度随深度而递增的三层固体介质、含硬夹层的三层固体介质而言，若频率f→OHz，其基阶模式的瑞利波相速度V〓→V〓（V〓为最底层介质的瑞利波速度）；若f→∞，其基阶模式的V〓→V〓（V〓为最上层介质的瑞利波速度）；因此，随着频率f逐渐升高，野外实测的瑞利波相速度V〓曲线应该主要为基阶导波模式。

Therefore the dispersion curves obtained in the field are primarily consisted of the first mode. For a heterogeneous elastic solid consisting of three homogeneous layers whose interlayer has low velocity, the phase velocity V〓 of the first mode will also close up to the Rayleigh wave velocity of the bottom layer when frequency f→OHz, but V〓 of the first mode will close up to the shear wave velocity of the interlayer when f→∞, and there is a cut-off frequency at high frequency region for the first mode and V〓 close up to the compressional velocity of interlayer when interlayer is liquid.

当三层固体介质中存在软夹层时，若f→OHz，则其基阶模式的相速度V〓→V〓（V〓为最底层介质的瑞利波速度）；若f→∞，其基阶模式V〓→V〓（V〓为中间层介质的横波速度）；若三层介质中存在液体夹层，当f→OHz时，基阶模式V〓→V〓，而基阶模式在高频段存在一个截止频率，截止频率处的瑞利波速度V〓→V〓；由此可判定，野外实测的相速度频散曲线不仅有基阶导波模式，同时还应有高阶导波模式波的存在，接收信号中存在模式间的跳跃，因此频散曲线会产生"之"字形现象。

A false signal in telecommunication links from beats between signal frequency and sampling frequency .

在脉冲编码调制中，信号频率和取样频率之间的差拍所引起的伪信号。

Electronics A false signal in telecommunication links from beats between signal frequency and sampling frequency.

假信号：信号频率和取样频率之间的拍子在无线电通信线路产生的假信号 adv。

The subsequent signal recovered from the samples will not contain the high frequency component of the original signal and will display a false low frequency signal.

以低于信号中最高频率两倍的频率进行信号取样时出现的一种效应，即当由取样状态还原时，还原后的信号将不再含有原来信号中的高频成分，并将显示出虚假的低频信号。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。