查询词典 period of oscillation

In this article, we will use this novel finite particle method to analyse several important and interesting dynamics problems in neat/insighting style, including the maximum and minimum period problem of the compound pendulum oscillation, plane impact problem and the spin and precession direction problems of the oblate and prolate satellites.

本文将透过先进的有限质点法，以极简的风格来分析几种重要而有趣的动力问题，包括复摆的最大及最小周期、刚体的角碰撞问题、薄碟型人造卫星公自转反向问题以及细长型人造卫星公自转同向问题。

The parameter of the cosine function affects the center of time gravity of the cosine-Gauss pulse in a certain range, even for the cosine-Gauss pulse whose pulse width is longer than one optical oscillation period.

余弦函数的参量在一定取值范围内对余弦-高斯脉冲也有较大的影响，它可能导致几周期余弦-高斯脉冲的时间重心有较大的漂移。

According to the variations in friction coefficient, wear rate, temperature of tribo-pair and tribo-surface micro hardness with time, the tribological process lubricated by oil containing Mg_6Si_4O_(10)_8 shows quasi-periodicity with characteristic of damped oscillation, and quasi-period is 200 h; micro-hardness of the worn surface is one time higher than that of 45~# steel substrate.

在实验室条件下，验证了主要组分为Mg6Si4O108的金属磨损自修复剂在45#钢摩擦副表面形成修复保护层的能力，得到了厚3～6 μm的反应层；采用Falex型摩擦磨损试验机进行了长达400 h的摩擦磨损试验，研究了在Mg6Si4O108润滑下45#钢摩擦副的摩擦磨损性能、摩擦副摩擦表面显微硬度和温度随时间变化的情况。

The calculation shows that the transition amplitudes display some damped oscillation with a period inversely proportional to the energy gap between the initial and final states and a damping time determined by the inter-molecular potential of the collision system.

对b与v对θ_的影响的分析表明，在物理上有意义的b和v的范围内，CO-He体系的θ_分布在30°～70°范围内，CO-HCl体系的θ_分布在93°～116°范围内，故不存在正负干涉抵消的问题，"平均效应"不严重。

The joint effect of active and reactive power on the voltage stability of a typical power system was considered by analysing the two parameter bifurcation problem related to nonlinear oscillation phenomena. Numerically, as the active power P1 increases, the Hopf points get closer and eventually coincide at P1=1.455 43 the cyclic fold curve gets closer and closer to the Hopf curve and finally intersects the Hopf curve at a singular point the period-doubling points also get closer and finally coincide at P1≈0.65. The stability behaviour is pre-determined using the normal form approach near the limit point of the Hopf curve. Hence, in the power system attention should be paid to both the consumption of active power and the decrease in the reactive power to prevent nonlinear oscillations. A controller can be designed to absorb some active power and to avoid the nonlinear oscillations that damage the system components.

针对一个典型的单机无穷大电力系统，通过分析系统的双参数分岔的非线性振荡现象，综合考虑有功和无功功率对电压稳定性的影响数值分析表明，随着有功功率的增加，电力系统的Hopf点越来越靠近，最终合为一点在P1=1.455 43处同时圈折cyclic fold 曲线也越来越靠近Hopf曲线，并在Hopf曲线的稳定与不稳定临界点处与Hopf曲线相交倍周期分岔点也随着越来越靠近，最终在P1≈0.65 合为一点应用正规形理论方法，初步确定了Hopf曲线极限点附近的稳定性态因而，电力系统应注意让负荷利用有功功率，减少无功功率的产生以防止非线性振荡另外，可以设计一个稍微吸收网络的有功功率的控制器，以避免因周期振荡而造成电力系统仪器的损坏或电压崩溃

The results show that the variations of summer temperature and precipitation in Chongqing contain obvious staggered features. The variations of precipitation are more complex than that of temperature. Three\|year period\|oscillation of mean temperature variations is the strongest,...

结果表明，重庆市夏季气温及降水变化具有明显的阶段性，且降水变化较气温更复杂；重庆市夏季平均气温变化以3年周期振动最强，而降水变化则以10年周期振动最强。

It shows that it is possible to increase the start oscillation length by tailoring magnetic field's amplitude and its period without changing the synchronous condition of the fundamental wave;in the meantime, when there are two or more azimuthally asymmetric space harmonics in the high power broad-band helix TWT, the influences of the Pierce's gain parameter, space charge parameter, and loss parameter on the start oscillation length and real starting asynchronous velocity parameter are also analyzed.

研究结果表明：改变聚焦磁场的幅值或周期来增加起振长度是可能的，而且不会改变基波的互作用条件。与此同时，对起振长度、初始非同步速度参量随皮尔斯增益参量、空间电荷参量、损耗参量等的变化，以及在超宽带行波管中当存在两个或多个角向非对称空间谐波时，起振长度、初始非同步速度参量随周期永久聚焦磁场的变化进行了研究。

According to the energy conservation theory, BOM and CSIM4 were coupled. The BOM has no treatment on transmission solar radiation, which is of great importance when the model is adapted to Arctic Ocean. So the treatment was introduced to BOM. Through numerical test on different lead albedos, it was found that sea ice thickness is not so sensitive to lead albedo, which may be contribute to the lead occupies little ratio within multiyear sea ice pack. The reason of summer over-melt of arctic sea ice is the NCEP reanalysis downward solar radiation being larger than its reality. Then the arctic sea ice climate variability was simulated. Results showed that: simulated ice thickness change is in accord with the submarine investigated mean sea-ice draft changes. Simulated annually maximum ice thickness along the Eurasian continental oceans are closely related to the observed ones. The long-term mean simulated ice motion has the same features of the SSM/I derived ice motion. Sea ice extents in differential sub-regions have same trends comparing to the satellite passive-microwave data derived ones. Simulated ice concentration is closely related to the observed in the Arctic sub-regions. Sea ice flux through the Fram Strait involves ice concentration, motion and thickness. It is a composite criterion for sea ice model evaluation. The simulated ice area and volume export through the strait accord with the satellite derived or statistically reconstructed ones.(5) The simulated ice thickness climate variability and mean sea surface current of the coupled model were analyzed, results showed: the total ice volume in the Arctic Ocean has a significant decreasing trend. The volume variability is of a 10-year timescale oscillation, with two major periods of 12-13a and 18-20a. Mean ice thickness in the arctic sub-seas has different tendencies. It has an increasing trend in the Barents-Kara Sea and Baffin Bay-Labrador Sea, and decreasing in the others. The characteristic time scale of 7-10a wherein the river discharges leads the Fram Strait ice volume export is about the period that river water takes to be conveyed across the Arctic Ocean.(6) Using the simulated ice distribution in the Arctic Ocean and China precipitation, air temperature and SST in tropical key regions, the climate teleconnection were studied. Result showed: When the mean sea ice thickness is large in the central Arctic Ocean and Chukchi-Beaufort Sea , and small in the Barents-Kara Sea and Baffin Bay-Labrador Sea , the precipitation in South China, Tibetan Plateau, and the north part of Northeastern China are always smaller than normal, and v. v. When the mean ice thickness is small in CA, BC, East Siberian Sea and Greenland-Iceland-Norwegian Sea , and large in BL, The air temperature in north-eastern China, the southern of Tibetan Plateau, and Hainan Island, are always lower than normal, and v. v. In addition, when the sea ice is thick in BC and BL, the SST is larger in the middle and eastern Pacific Ocean, and is smaller in the tropical Southeastern Indian Ocean.

由于BOM没有考虑透射太阳辐射的物理过程，研究表明透射太阳辐射对北冰洋的能量收支起到重要作用，因此在BOM模式中引入了对透射太阳辐射的处理；通过对不同水道反照率的数值试验表明海冰厚度对水道反照率的敏感性不强，可能与海冰区水道面积占的比率很小有关；而模式模拟的北极海冰夏季&过度融化&主要源于NCEP再分析资料提供了偏大的太阳短波辐射；对北极海冰的气候变率进行了模拟研究，结果表明：模拟的海冰厚度变化与潜艇探测的海冰吃深度变化具有一致性；模拟和观测的亚欧大陆沿海的年内最大海冰厚度有很好的相关；模拟的海冰移速与长期平均的卫星反演的海冰移速具有相同的速度分布特征；模拟的各个海区海冰面积的变化趋势与卫星反演资料分析的结果基本一致；模拟与观测的主要海洋分区的海冰密集度具有很好的相关：弗瑞姆海峡的海冰体积和面积的输送涉及到海冰密集度、厚度和移动速度，是判断模式模拟能力的一个综合的指标，模式模拟的结果与卫星反演或重建的面积输送、体积输送具有很好的一致性；(5)分析了模拟的北极海冰厚度的气候变率及气候平均表层海流场，结果表明：北极海冰的总体积有显著减少的趋势，北极海冰总体积的变化具有10a际尺度振荡的特点，存在18-20a和12-13a两个主周期；北极海冰的平均厚度在各个海区的变化趋势不同，在巴伦支—喀拉海和巴芬湾—拉布拉多海地区海冰厚度有显著的增加趋势，而其它海区存在减少的趋势；通过对模拟的气候平均表层海流的分析表明，北极河流流量超前弗瑞姆海峡海冰流量7-10年的特征时间尺度与表层海流的气候分布存在着必然联系：(6)利用模拟结果以及中国降水、气温和热带关键区SST资料，讨论了北极各海区海冰平均厚度与中国降水、气温以及热带关键区SST的关系，结果表明：在北极中心海区和楚科奇—波弗特海海冰厚度偏大，在巴伦支—喀拉海以及巴芬湾—拉布拉多海海冰厚度偏小，则中国降水在华南地区、青藏高原和东北北部降水偏少，反之相反；在北极中心海区、东西伯利亚海、楚科奇—波弗特海以及格陵兰海海冰厚度偏小，在巴芬湾—拉布拉多海海冰厚度偏大，则在中国东北地区、高原南部地区和海南岛附近气温偏低，反之相反；另外，北极楚科奇—波弗特海和巴芬湾—拉布拉多海海冰厚度偏大时，在热带中东太平洋海温偏高，而在热带东南印度洋海温偏低。

These data,especially the seiches with relatively large amplitudes,were examined by using statistics and natural period analysis.Basic chracteristics of seiches,such as monthly and annual occurrences,oscillation period, occurrence duration and occurrence time of the peak,were derived. Among these 20 tide-gauge stations...

结果表明，该海域主要港湾假潮出现具有明显的局地性、季节性和年际变化；夏季是大振幅假潮(振幅1 )≥ 80cm的多发期，冬季基本上不出现；龙口港湾的大振幅假潮最为突出，最大振幅可达 2 93cm ；气压和风速、风向突变的良好配合，是发生大振幅假潮的主要原因

Based on the return map and the principle of closed vectors, a new method is proposed to extract unstable periodic orbits embedded in chaotic attractors. As examples, the UPOs embedded in chaotic attractors of Logistic, Hénon and Lorenz are extracted respectively by this method. And our results of Skewed Hénon map also be compared with Nusse's. These results suggest that this method is valid for unstable periodic orbits from period one to period infinite of arbitrary dimension chaotic system. The dynamic considerations of spiking and UPO coding for individual neuron and neural system under external periodic and chaotic exciting stimulus also be studied in this dissertation. A lot of spiking phenomena, such as synchronization, period, and chaos appear alternatively with the changing of the stimulus frequency. For the small stimulus frequency the neuron could completely convey the periodic signal in synchronous anti-phase into interspike intervals sequences. For the slow time–scale chaotic input, the output two ISI sequences are reciprocally related to input signals, and their oscillation wave shape in time course can be derived from that of the input signals variation, furthermore, the similar input sequence and order of UPOs, distribution of LES and value of KYD remain in attractors reconstructed from ISI sequences.

发现周期信号在单个神经元传递过程中，随着激励频率的改变，神经元输出的峰峰间期interspike interval时间序列呈现出周期、混沌和准周期的交错变化，特别当外加激励信号频率较低时，周期信号可以通过神经元ISI序列以反相同步的周期运动形式传递下去；同时无论是周期还是混沌激励信号，在神经系统中的传递均与其自身强度和神经元之间的耦合强度的大小密切相关；快变时间尺度的混沌激励信号在耦合的神经系统传递过程中，会造成大量基本信息的丢失；而慢变时间尺度的混沌激励信号在神经系统传递中，它的非线性特征信息，如混沌吸引子、不稳定周期轨道、Lyapunov指数谱和分形维数，会通过系统输出的ISI序列部分地重现出来，如与输入慢变时间尺度的混沌激励信号相比，神经系统输出的ISI序列具有：相似几何形状的混沌吸引子、相近的Lyapunov指数谱和分形维数、局部结构相同的不稳定周期轨道的排列方式。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。