技术好地

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。

To better integrate the decision progress with the technology of data warehouse, a mathematical description of the general problem's decision-making process was proposed and the knowledge classification of decision domain based on the mathematical description was provided as well.

为了将数据仓库技术和决策过程更好地结合，给出了一般问题决策过程的数学描述以及在此基础上的决策空间的知识分类。

The factors affecting the quality of instantaneous detonator used in coal mines are analyzed.

通过对影响煤矿许用瞬发电雷管产品质量诸因素的分析，找出了提高该产品质量的工艺技术途径，为更好地生产该产品奠定了基础。

In view of the usual vertical-horizontal elastic mesh's shortage in left falling stroke and right falling stroke, we present a new elastic mesh structure method—diagonal elastic mesh, which is composed of diagonal beelines of and , and divides the Chinese character image into many diamonds.

针对通常的纵横弹性网格对汉字"撇、捺"笔画特征提取的不足，提出一种新的网格构造技术——对角弹性网格，它由45°和135°的对角直线构成，将汉字图像划分为多个菱形，能够很好地适应汉字在"撇、捺"方向的变化。

Technology savvy investors who have the knowledge and confidence to make their own trading decisions are better off with a discount broker.

技术精明的投资者，他们拥有的知识和信心，让他们自己的交易决策，是更好地起飞的折扣券商。

Discrete spectrum existed in power spectrum of output single are weaken and the power spectrum become consecutive because of using randomized modulation.

随机调制技术较好地减小了输出信号中的离散功率谱，使输出信号的功率谱趋于连续。

Disputation about copyright can be settled down by using the watermark embedding technique presented in this paper.

利用本文的水印技术可以较好地解决版权争议等问题。

Hydrostatic bearing can solve the equilibrium problem of axial force of multistage centrifugal pump satisfactorily.

液体静压支承技术可以很好地解决多级离心泵轴向力的平衡问题。

"Climbing in China continues to grow as new areas are developed and the standards are continually raised," comments Ryan Gellert, Managing Director of BD Asia. We have a number of events and programs planned for the upcoming year in China aimed at serving both climbers and outdoor retailers. These include hosting a climbing festival, adding event and additional technical info to our Chinese language website, and developing pro purchase and strategic retail partner programs.

"BD亚洲的董事总经理Ryan Gellert说，"在未来的一年中，为了更好地服务于攀登者和户外产品零售商，我们将会推出一系列的活动和项目，其中包括组织攀登节，在我们的中文网站上增加更多攀登和滑雪器材的技术知识，以及与中国有关的攀岩、攀冰和登山等活动和赛事的介绍等信息，同时我们还将推出零售合作伙伴项目和攀登精英会员计划。

The latest development of virtual machine technology provides a new approach to integrate resources in grid environment.Its encapsulation,isolation and security can shield resource heterogeneousness,enable application specific execution environment,and provide better adaptability to the environment complexity and application diversity.

虚拟技术的最新进展为网格计算提供了封装资源的新方式，其封装性、隔离性和安全性能够有效屏蔽底层资源的异构性，根据用户应用需求定制执行环境，更好地适应于网格环境的复杂性和应用的多样性。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。