临界

Melnikov method is employed to study the bifurcations and chaos of homoclinic and subharmonic orbits for two pendulum systems.

用Melnikov方法研究具有弱阻尼与参数激励的单摆以及倒摆运动的同宿轨道分岔、次谐分岔和混沌现象，得到了发生同宿轨道分岔、次谐分岔和混沌的临界参数，并将所得理论结果与倒摆运动的实验结果进行了比较与讨论。

Self-assembled nanomicelles of N -cholesterol succinyl O -carboxymethyl chitosan were prepared by probe sonication method. The amphiphilic property and the critical micelle concentration of CCMC were determined by fluorescence probe technique; the morphology and the size of CCMC self-assembled nanomicelles were analyzed by transmission electron microscopy and the dynamic laser light scattering.

以 N -胆甾醇琥珀酰基- O -羧甲基壳聚糖(CCMC，胆甾醇基取代度6.9%)为原料，在水溶液中通过探头超声处理制备其自组装凝胶纳米胶束，采用稳态荧光探针法考察临界胶束浓度，并通过透射电镜和动态激光散射仪检测胶束的形态大小。

Of course, there is a criticality today as the atmosphere in the region surrounding Afghanistan threatens to become sulfurous with blinding speed.

当然，随着在阿富汗的周围地区气氛威胁带着让人眼花缭乱的速度变得含有火药味今天有一临界。

Test results show that the equivalent strain method exhibits a higher life assessment precision as compared to that by linear damage summation. The critical damage formula for equivalent strain can quite well predict the actual damage incurred and the equivalent strain-life curve with hardness modification fundamentally conforms with the pure fatigue strain-life curve.

试验结果表明，在预测寿命时等效应变法比线性累计损伤法具有更高的精度，等效应变的应力下临界损伤公式能够很好地预测实际损伤，考虑硬度修正的等效应变-寿命曲线和纯疲劳应变-寿命曲线基本一致。

The critical bifurcation parameter intervals of superharmonic periodic impact motions are deduced, and numerical simulations are used to verify the results.

本论文讨论了碰撞振动系统的周期碰撞运动，得到了超谐周期碰撞运动的存在性和稳定性，推导出亚谐周期运动的临界分岔参数区间，并利用数值模拟进行验证。

After undergoing a chaotic region, the period number will add one, in the same time, magnitude of the subharmonic response increases in sequence as the rotational speed ratio increases. When the rotational speed is below the critical speed, the chaotic bands resulted directly from a perioddoubling bifurcation occur among the successive orders of superharmonic responses, then they can return directly to periodic motion by a reversed period-doubling bifurcation.

在转速小于临界转速的情况下，在分岔图中各个连续阶亚谐运动的转换区中分别都出现了经由一个倍周期分岔直接导致的混沌频带，后又直接由一个逆倍周期分岔转化为周期一的运动，同时在三个混沌频带之间都出现了幅值突跳的现象。

In this dissertation, periodic impact motions in vibro-impact systems are studied, and the existence and stability of superharmonic periodic impact motions are obtained. The critical bifurcation parameter intervals of superharmonic periodic impact motions are deduced, and numerical simulations are used to verify the results.

中文题名碰振或约束系统的全局分析及稳定性研究副题名外文题名 Studies on global analysis and stability in vibro-impact or constraint systems 论文作者张彦梅导师陆启韶教授学科专业一般力学与力学基础研究领域\研究方向学位级别博士学位授予单位北京航空航天大学学位授予日期2002 论文页码总数95页关键词碰振系统转子系统多体系统碰撞振动馆藏号BSLW /2003 /O322 /1 本论文讨论了碰撞振动系统的周期碰撞运动，得到了超谐周期碰撞运动的存在性和稳定性，推导出亚谐周期运动的临界分岔参数区间，并利用数值模拟进行验证。

What determines a particle's potential for nucleation is its "critical supersaturation".

粒子的"临界过饱和"决定了它的成核潜力。

As for the three-story frame, the beams provide the restriction when the column lost their stability. So the overall sustention ability of the beam could be distributed to the border columns. The overall critical load of the three-story frame could be extracted by solving the equation with two variables.

对于三层斜腿框架的整体稳定性研究，本文考虑梁在框架中的作用对柱而言就是在失稳时对柱提供约束，根据层与层互相支援的思路，以梁在上下层分配的约束为未知量，通过求解二元方程，得到三层斜腿钢框架整体失稳的临界荷载。

From the point of view of the dynamic process ofmagneto-thermal interaction, the ambient temperature and sweep rate of the externalmagnetic-field are taken into account to develop the theoretical models of the effect ofdistribution of non-uniform critical-current density on flux jumps by solvingpredicting equations for predicting the first flux-jump field.

本文采用局部绝热假定从磁热相互作用的角度考虑临界电流密度非均匀分布效应对磁通跳跃和交流损耗的影响并对高温超导薄膜的磁场和电流密度的分布及其损耗情况进行了深入研究，得到了一些有意义的结果。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了