时计的

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。

Radar rainfall estimation combined with a few rain gauges has as good result as dense rain gauge network does in runoff simulation that gives a good prospect of radar application in flood monitoring and forecasting.

2雷达联合少量雨量计估测降水用于流域径流模拟时，模拟精度和用稠密雨量计网模拟的精度接近，显示雷达在流域径流模拟和洪水监测预报中有相当高的应用价值。

Optical time-domain reflectometry located the regions where optical attenuation occurred due to leakage; optical power meter acquired the transmitted power at the end of fiber, and these events could be identified according to the characteristics of signals.

在光入射端，用光时域反射计对上述事件引发的损耗进行定位；在光输出端，用光功率计检测光功率的变化，并根据信号特徵来判定事件的类型。

The readings of the refractometer should be calibrated before use with a prism of against water.

测定前，折光计读数应用校正用棱镜或水进行校正，水的折光率20℃时为1.3330，25℃时为1.3325，40℃时为1.3305。

Finally, we should emphasize that besides combing the explorations and researches on the time and frequency domain of traditional pulse wave signals, the central of subproject focuses on the realization of pulse wave signals to design a sphygmography with objective measurement by combining the results of the other two subprojects and clinical diagnoses and pulse condition analysis, in order to equip the sphygmography with automatic diagnostic functions and friendly user interface.

最后，要强调的是本计画的技术核心，兼并传统脉波信号时/频域探讨研究外，并著重在脉波信号定位与实现，以结合另外二个子计画，设计出一具有客观测量的脉诊仪系统，再配合临床疾病诊断与脉象分析，使脉诊仪具备自动诊断功能与人性化之人机界面。

Commonly, original "tax basis" is book value of assets, however whether there is discrepancy for entry value and tax basis and deduction of retained earnings in certain restructuring transaction shall be taken into consideration while determining original "tax basis".

通知》虽未明确，但我们认为原"计税基础"的确定还应考虑资产取得时入账价值和计税基础是否有差异，且在某些重组交易中，还应当考虑转让方留存收益的扣除。

The products are applied to measure the level of vaporizable liquid especially liquefied gas. Blocking lever is used to divide guide tube into gasification chamber and measure chamber. When liquefied gas is infected by temperature and vaporize into being gas bubbles, the bubbles will rush up along gasification chamber and not enter into measure chamber to affect magnetic float.

该产品适用于易汽化的液体测量，尤其适合液化气介质的液位测量；其特点是用挡杆将液位计主导管内腔分成气化室和测量室，当液位计内液化气受温度影响，内部汽化而产生气泡时，气泡会顺着气化室往上冒，而不会进入测量室影响磁浮子工作，有效地阻止了因气泡

Research shows that relative pessimists are more accurate at gauging success and failure rates at a simple laboratory task than optimists, who undercounted failures and overcounted successes, says Edward Chang, associate professor of psychology at the University of Michigan.

密歇根大学心理学副教授Edward Chang说，研究表明，在统计一项简单实验的成功率时，与乐观主义者相比，相对悲观的人能获得更准确的数据，而乐观主义者会少计失败次数而多计成功次数。

It ranges from 10~(-2) to 5×10~(-10) torr. In this paper, the method which extends the upper limit of B-A gauge and the characteristics at high pressure are described.

本文介绍此规管在拓宽 BA计上限方面所采取的措施及BA计在高压强时的特性。

The article analyzes the cause of unequal LPG tank storage between computation and fact and indicates glass board type level meter and LPG tank have difference in temperature due to environment temperature changed. That's the reason which causes the storage error.

文章分析了在计量液化气储罐内的存量时库存和实际不相符的原因，指出玻璃板式液位计由于环境温度变化，使液化石油气储罐和液位计导管温度存在差异，势必会产生液位偏差。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。