查询词典 critical damping

The four varistors form the Wheatstone full bridge. Two lateral sides of cantilever and overload protection structure are fabricated using DRIE technology. A novel overload protection curvature is designed to be similar to the cantilever bending shape which is bearing the greatest acceleration. This design increases the overload protection and improves the vibration damping of accelerometer to the critical damping.

悬臂梁两侧面和过载保护曲面采用DRIE技术加工，过载保护曲面设计成近似于冲击加速度传感器承受最大加速度时悬臂梁弯曲曲面的形状，一方面提高了悬臂梁过载保护能力，另一方面可以调节加速度传感器的工作阻尼至临界阻尼，有效提高了加速度传感器的工作频率带宽。

Chapter four studies the chaotic responses in a system consisting of simple pendulum and harmonic oscillator under bounded noise excitation. Firstly, the Melnikov function of the two-degree-of-freedom system under Hamiltonian perturbation is derived. The essential condition of the autonomous system for the probable onset of chaos is obtained, the Poincare maps of the system under small Hamiltonian perturbation and the effect of increasing perturbation on the Poincare maps are studies. Then for the non-autonomous system under damping and harmonic or bounded noise excitation, the largest Lyapunov exponent and Poincare maps are calculated. From the analysis of the largest Lyapunov exponent, the critical criterion for the onset of chaos, and the conclusion that the threshold of bounded noise amplitude for the onset of chaos in the system increases as the intensity parameter of Wiener process increases are obtained. The result from the analysis of Poincare maps is in agreement with that obtained from the Largest Lyapunov exponent. The effect of varying damping coefficient and intensity parameter of Wiener process is also analyzed.

第四章研究了有界噪声激励下的两自由度单摆—谐振子系统的混沌运动，首先推导了该两自由度系统仅在Hamilton扰动下的Melnikov函数，得到该自治系统可能产生混沌的必要条件；研究了该系统在小的Hamilton扰动和增大摄动情形下的Poincare截面；然后对有阻尼、谐和或有界噪声激励下的非自治系统数值计算了其最大Lyapunov指数和Poincare截面；从Lyapunov指数分析得到了这个两自由度系统产生混沌运动的临界条件及产生混沌的临界激励幅值随Wiener过程强度参数值的增大而增大的结论，Poincare截面分析的结果亦符合Lyapunov指数分析的结论；研究了Wiener过程强度参数、阻尼系数变化对Poincare截面的影响。

In this paper the nonstationary vibration behavior of an unbalanced rotor system, which is assumed to be bending flexible but torsionally rigid, during acceleration or deceleration through the critical speeds is investigated. Influencing factors such as gyrascopic effects, external and internal damping, Supporting mass, damping and stiffness, asymmetry of the shaft crass section as well as anisotropy of the supports are considered.

在理论分析方面，本文考虑了转子的陀螺效应，内外阻尼，轴截面的非对称性，支承的貭量、阻尼、刚度和支承的各向异性等因素的影响，使用分析动力学，建立起严格的运动方程，并考虑了弯曲自由度与转动自由度间的耦合，因而能较精确地分析和描述转子通过临界点时的非定常振动和转速变化規律。

The analysis results indicate that the vibration fractional factor with rotating frequency has a close relationship with both rotating speed of rotor and damping of bearing under constant acceleration. When rotating acceleration is small and damping is large, the transient response is not sensitive to the variation of rotating speed; otherwise the imbalance response with constant acceleration and the response in stable state will build up obvious differences near critical rotating speed.

研究结果表明：在恒加速条件下，转子同频振动分量与转子的转速、支承阻尼等因素密切相关，当角加速度较小且阻尼较大时，其瞬态响应对转速的波动不敏感；而当角加速度较大或阻尼较小时，恒加速过程不平衡响应与稳态响应在临界转速附近将产生明显的差异。

The saturated liquid densities of HFC227ea and the vapor-liquid coexistence curve were measured, the critical temperature and critical density were determined by the critical opalescence phenomenon, and then the critical pressure was determined by vapor pressure equation.

测量了HFC-227ea饱和液体密度和临界区的气液共存线，确定了HFC-227ea的临界温度、临界压力、临界密度；推算了HFC-227ea的饱和气体密度，并验证了其可信度；关联了饱和气液密度，提出了高精度的HFC-227ea饱和气液密度关联式；关联了临界区气液共存线，可精确再现HFC-227ea临界区性质，并根据临界幂定律导出了HFC-227ea的临界指数和临界幅值。

The paper studied the effects of five kinds of photoperiod(16、 14、 12、 10、 8h light/d) on the two cultivars of camellia japonica('White snow tower' and ' White-red peony').The morphological and physiological indexes relative to growth were measured. Then the critical daylength and the flower bud differentiation of ' White snow tower ' and ' White-red peony' were defined. The results indicated:(1)Camellia japonica was long-daylength plant, and different cultivar had different critical daylength,the critical daylength of 'White snow tower' was about 14 h light/day,while the critical daylength of 'White-red peony' was about 12 h light/day.

本试验以山茶花的两个栽培品种&白雪塔&与&花牡丹&(White-red peony)为材料，主要研究光周期对山茶花成花的效应，通过测定不同光照长度(16、14、12、10、8小时/天)对其生长发育相关的形态指标和生理指标的影响，确定了&白雪塔&与&花牡丹&的临界日长和花芽分化进程。

In this paper, it is pointed out that the accuracy of measurement must be considered for the discussion about the restitution time of damped vibration, and it is in the "critical state of weakly damped vibration" defined by this paper, not the critical damping state, that the restitution time is the shortest.

1 问题的提出和回复时间的定义众所周知，阻尼振动按阻尼的大小可分为弱阻尼、临界阻尼和过阻尼三种情形。几乎所有的教材均指出，临界阻尼运动是物体刚能不做周期性运动而又最快地回到平衡位置的运动，也即其回复时间最短。

After the airdrop experiments of the system of the projectile and speed-down parachute, the balance velocity obtained from the optics apparatus on the ground、the balance spinning speed obtained from the gyroscope on the projectile and the image obtained from the infrared detector on the projectile are all used to simulate the six-dimension exterior trajectory of the projectile and identify the roll damping moment derivatives, and the identification can safely come to a conclusion that the absolute value of roll damping moment derivatives from the engineering calculation are on the low side.

对卷弧尾翼弹与减速伞系统进行空投试验，由地面光测系统给出平衡落速、弹上陀螺给出平衡转速、弹上红外探测器拍摄地面图像判断弹的姿态。通过六自由度弹道模拟，对弹滚转阻尼导数进行参数辨识，得到工程估算所得滚转阻尼导数绝对值偏小的结论。 5。对空投试验中出现弹姿态摆动现象，从受力分析及红外图像分析两个方面进行探讨，给出合理解释，并根据分析对弹外形进行修改，在后来的试验中收到很好的效果。

As air damping directly determines the dynamic performance of MEMS, it is very important to estimate the air damping effects on them in the design process.

对空气阻尼进行定性和定量分析是MEMS器件设计中非常重要的一个步骤，直接影响MEMS器件的动态性能。

The air damping of the laterally driven microstructures is slide-film air damping.

对于横向运动的体微机械器件，其周围空气表现为滑膜阻尼。

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。