查询词典 angular acceleration

Contributions of the centripetal acceleration in steady flight, the tangential acceleration due to the effect of the angular acceleration, the Coriolis component of acceleration, the radial (the vertical direction at prototype), circumferential and axial (the two horizontal directions at prototype) shaking effects and the elongation effect of the centrifuge arm to the global acceleration of a particle in centrifuge modelling are identified in the expression of the global acceleration.

笔者描述了整体加速度表达式中各项的物理意义，指出了离心机稳定运转时的向心加速度、由角加速度效应引起的切向加速度、互补加速度分量、径向、环向和轴向振动效应以及离心机臂伸长效应对整体加速度的贡献。

A new method to measure the mechanical angular acceleration of rotating system is established by changing the exciting mode of AC asynchronous tachogenerator,and form a angular acceleration tachogenerator to measure the mechanical angular acceleration directly.

摘 要：提出的旋转系统机械角加速度直接测量方法通过对交流异步测速发电机励磁方式的改变，构成了能直接测量机械角加速度的测旋转角加速度发电机。

A new method to measure the mechanical angular acceleration of rotating system is established by changing the exciting mode of AC asynchronous tachogenerator, and form a angular acceleration tachogenerator to measure the mechanical angular acceleration directly.

提出的旋转系统机械角加速度直接测量方法通过对交流异步测速发电机励磁方式的改变，构成了能直接测量机械角加速度的测旋转角加速度发电机。

Week 5 Angular momentum of particle and conservation law of angular momentum, angular momentum of rigid body, theorem of angular momentum, conservation law of angular momentum.

第5周 质点的角动量和角动量守恒定律，刚体的角动量、角动量定理、角动量守恒定律。

The conclusion is that the extent of the zenith blind zone was restricted by three parameters: maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. In astronomical coordinates (reference mark is north latitude 43. 9°), analyzed is the effect of azimuth angular velocity, acceleration and altitude angular velocity, acceleration etc. Some formulae were given to compute all correlative quantities.

在观测坐标系中推导出确定天顶盲区理论范围公式和满足过天顶跟踪条件的关系式；在天文坐标系中以长春卫星观测站（北纬43.9°）作为计算基准，分别讨论了方位、俯仰方向的角速度、角加速度等对天顶盲区的影响，在理论分析上为解决过天顶跟踪问题打下了基础。

The conclusion is that the extent of the zenith blind zone was restricted by three parameters: maximum azimuth angular velocity of tracking mount, flight level and airspeed of the target. In astronomical coordinates (reference mark is north latitude 43.9 ), analyzed is the effect of azimuth angular velocity, acceleration and altitude angular velocity, acceleration etc. Some formulae were given to compute all correlative quantities.

在观测坐标系中推导出确定天顶盲区理论范围公式和满足过天项跟踪条件的关系式；在天文坐标系中以长春卫星观测站(北纬43.9°)作为计算基准，分别讨论了方位、俯仰方向的角速度、角加速度等对天顶盲区的影响，在理论分析上为解决过天顶跟踪问题打下了基础。

The acceleration profile of the crane motion is designed to induce minimum payload pendulation during transpo rt,while the deceleration stage is designed to ensure freed om of residual oscillation near the end of the transport,and to deliver the payload at the target point.The techniques induce payload pendulation at least one half ofan oscillation cycle or integer multiples during each of the acceleration and deceleration stages.Starr(1995)designed a symmetric two-step acceleration and deceleration profile to transfer a suspended object.The duration on the constant acceleration steps is assumed to be negligible relative to the period of the payload oscillation.A linear approximation method of the oscillation period is used to generate the two-step symmetric acceleration profile.

3.1投入成型技术，各种形式的投入shapers ， convolved参考命令，产生形投入指挥，驾驶起重机提出一套距离沿一套path.the加速度概况起重机议案旨在诱使最低载重pendulation期间transpo rt ，虽然减速阶段，目的是确保freed om残余振荡接近尾声的运输，并交付载荷到达目标point.the技巧诱使载荷pendulation至少一半ofan振荡周期或整数倍数。

And the concept of angular dispersion of diffractive polar angle(the first kind angular dispersion) and angular dispersion of diffractive azimuthal angle (the second kind angular dispersion) are established.

确立了二维平面光栅衍射极角角色散和衍射方位角角色散的概念。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

Because the body inertia in ball hitting moment was very small, the angular momentum was mainly affected by angular velocity. In the phase, the average value, largest value and hitting moment value of angular momentum with kick hitting are larger than those with glide hitting. Therefore, the kick hitting could get larger linear and angular momentum.

此阶段平均身体角动量、最大值与击中球瞬间，抬腿击球法三者平均角动量均大於滑步击球法，因此抬腿击球法技术的旋转特质与优势在这可以清楚的看出到，意谓著抬腿击球法打击技术可以使球获得较大的动量与角动量。

"Bird Man's Diary, Butting on the Love Island", Changsha, China

2008年"鸟人日记，顶在爱情岛"，中国长沙

As long as they were in the service of a family of wizards, their magic would remain dormant.

只要他们一天为家庭服务，他们的法力就潜藏不动。