周期

Based on VHZ data recorded by 7 stations of China digital seismograph network for Nov. 14, 2001, earthquake in the west of the Kunlun mountain pass, we extracted spherical mode of 0S4-0S76 of the earth free oscillation using power spectral density estimation. Because the frequency response of seismograph in China digital seismograph network suppress information of solid tide, we do not need to remove the solid tide in our procession.

利用中国数字地震台网改造后的7个台站的VHZ波形资料，采用功率谱密度估计方法，利用中国数字地震台网地震仪对低频信号压制的特点，在没有对资料去除固体潮影响的情况下，提取了2001年11月14日昆仑山口西地震激发的0S4-0S76地球球型自由振荡，并与地球初步参考模型的理论自由振荡周期进行对比，结果表明与PREM预测的球型自由振荡周期符合得很好。

In Chapters 3 and 4, we investigate the existence of periodic solutions of a class of second order functional differential equation and a class of third order functional differential equation, respectively, and obtain new sufficient conditions of their existence result of periodic solutions under growth conditions and linear growth condition, respectively.

第三章与第四章分别研究了一类二阶泛函微分方程及一类三阶泛函微分方程的周期解存在性，分别在增长条件及线性增长条件下，获得了这两类方程周期解存在性的新的充分条件，与文献中已知结果比较，我们所讨论的方程更为一般，所得结果较简洁且易于验证。

In Chapters 3 and 4, we investigate the existence of periodic solutions of a class of second order functional differential equation and a class of third order functional differential equation, respectively, and obtain new sufficient conditions of their existence result of periodic solutions under growth conditions and linear growth condition, respectively. Compared with some known results in the literature, the equations discussed by us are more general, and our results are concise and easy to be verified.

第三章与第四章分别研究了一类二阶泛函微分方程及一类三阶泛函微分方程的周期解存在性，分别在增长条件及线性增长条件下，获得了这两类方程周期解存在性的新的充分条件，与文献中已知结果比较，我们所讨论的方程更为一般，所得结果较简洁且易于验证。

The fundamental learning cycle is individual, and the social learning cycle is much slower and the byproduct of many processes, the poorest one being consensus.

基本的学习周期是个人性的，社会学习周期慢得多，而且，许多过程最贫乏的副产品是取得共识。

Theoretically, for quasi-periodic audio signals, we can use the waveform within a fundamental period as the timbre of the frame.

直觉来看，音色的不同，代表基本周期的波形不同，因此我们可以使用基本周期的波形来代表音色。

One, the physical quantity that the fundamental point that the physical quantity that describes mechanical vibration and mechanical wave is proposition of the university entrance exam describes physical quantity of simple harmonic motion to the; such as amplitude, periodic, frequency, speed, acceleration, phasic, phasic difference describes mechanical wave has amplitude, wavelengh, velocity of wave, periodic, frequency to wait.

一、描述机械振动和机械波的物理量是高考命题的基础点描述简谐运动物理量有振幅、周期、频率、速度、加速度、相位、相位差等；描述机械波的物理量有振幅、波长、波速、周期、频率等。

However, because of the positive sequence of fundamental frequency, there are still some shortages for wavelet transform in the use of harmonic measurement of three-phase dissymmetrical system. A new approach of harmonic measurement based on Period-interleaving of MALLAT arithmetic for dissymmetrical system is put forward. Analysis and experiment based on TMS320LF2407 Digital Signal Processor are made. And the result of experiment reveals that the proposed method based on Period-interleaving is valid in the use of harmonic measurement of three-phase dissymmetrical system.

但是，目前小波变换在三相不对称系统的谐波检测中存在着无法分离基波正序信号的不足，本文就此提出了一种用于三相不对称系统的基于周期交错的小波MALLAT多分辨率分解的测量方法，详细介绍了该算法的原理、流程及计算公式，同时以TMS320LF2407数字信号处理器为核心建立了实验系统对该算法进行了实验，实验结果证明该周期交错－小波变换算法可以有效地检测出三相不对称系统中的有害电流。

The representation of sequences is very helpful for the research of their linear complexity,so this paper we first research trace representation of periodic sequences,and the trace representation of a New Generalized Cyclotomic Sequence of order two of length pq is given,then for 2~mp~n period binary sequences,where p is an odd prime and 2 is a primitive root modulo p~2,we present a relation-ship between the linear complexity and the minimum value k for which the k-error linear complexity is strictly less than the linear complexity and have the upper bound and lower bound of the value k, finally we discuss the k-error linear complexity of legendre sequences,also have the upper bound and lower bound of the value k,and discusses the situation where the linear complexity drop again for some Legendre sequences.

序列的表达形式对于其线性复杂度的研究是十分有帮助的，本文我们首先研究的是周期序列的迹表示，给出了2阶pq长度的扩展分圆序列的迹表示，然后讨论了周期为2~mp~n(m≥2)序列的线性复杂度与使得线性复杂度变小的最小的k值的关系，给出了k值的上界和下界，这里p为奇素数，2是模p~2的本原根，并通过例子讨论了其线性复杂度的稳定性，最后对Legendre序列k-错线性复杂度进行了分析，也给出了k值的上界和下界，并对某些Legendre序列讨论了线性复杂度再次下降的情况。

A new type of geophone is presented,based on the narrow band transmission and free of back reflection features of long period fiber grating.

基于长周期光纤光栅能透射特定波长的性质，以及其无后向反射的优点，提出一种新型的长周期光纤光栅地震检波器系统。

Trigger control circuit in accordance with pulse phase and input along the angle of the trigger value, the corresponding time delay after the rising edge of trigger pulse, open SCR, and in the corresponding half-cycle before the end of hair falling edge trigger pulse, turn-off thyristor, for the next half cycle of the trigger ready.

触发控制电路根据鉴相脉冲沿和输入的触发角数值，延迟相应时间后发出触发脉冲上升沿，打开可控硅，并在相应半个周期结束前发触发脉冲下降沿，关断可控硅，为下个半周期触发做好准备。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。