一定尺寸的

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。

From the results obtained in the study, the following conclusions can be made:The methylene blue and spectrophotometer method can capture the free radicals generated successfully. This is an effective way to measuring the free radicals quantitatively in cavitation, moreover it is easy to fulfill.The intensity of cavitation increases with reduction in the cavitation number. But the different mechanism of various enhancive processes (chemical and physical processes) results in different effect by cavitation number.The effect of operating parameters, such as inlet pressure, temperature and time on cavitation indicate that optimum operating conditions exist at the cavitation enhancive effect is maximum.It is important to optimize the structure of hydrodynamic cavitation reactor for achieving a desired effect. A reasonable geometric parameter can promote the enhancive effect for a fixed hydrodynamic condition.Ventilating appropriate gas to cavitating flow can increase cavitational intensity and hence promote the enhancive effect of hydrodynamic cavitation.

研究结果表明：亚甲基蓝分光光度计法，能够成功地捕捉到水力空化产生的羟自由基，是定量检测空化自由基简便易行的有效方法；空化程度随空化数的减小而增强，但对于不同的强化过程，因其强化机理不同，故空化数对强化效应的影响也不同；水力空化系统的压力、温度及时间等操作参数对空化强化效应的影响规律表明：在适宜的操作条件下可产生最佳的空化强化效果；空化发生器结构的优化设计是保证空化强化效应的重要前提，在一定的水力学条件下，合理的结构尺寸可以增强空化作用效果：往水流中适量加入干扰气体能够提高空化强度，增强空化强化效果。

In chapter 5, the concept of zero-span tension known in papermaking area is for the first time introduce to wood science area to explore in-tree variation of longitudinal tensile strength of tracheids and its main influencing factors. In chapter 6, composite micromechanics and classic laminated theory are used to make a comprehensive and detailed analysis of the main influencing factors of mechanical properties of tracheids cell wall. Some experimental results acquired in the foregoing chapters are explained successfully. Results were summarized as follows: Mechanical characteristics of wood at micron scale: 1 At micron scale, the longitudinal mechanicai behavior of wood microtome section differs greatly from that of wood with normal size.

论文的第2章首先研究了微米尺度下木材的力学特性，为后面运用木材微切片拉伸技术奠定一定的理论基础；在第3章，首次考虑到了微米尺度下木材力学性质的尺寸效应，并运用木材微切片正常间距拉伸技术研究了管胞纵向弹性模量的株内变异规律；在第4章，首次利用纳米压痕技术中最新发展起来的连续刚度测量法直接在管胞细胞壁上进行纳米级的压痕实验，测量次生壁S〓层的纵横向弹性模量和硬度，从而把细胞壁力学的研究提高到一个更高的水平；在第5章，首次把造纸领域的零距拉伸技术引入木材科学研究领域，研究了管胞纵向抗拉强度的株内变异规律及其主要影响因素；第6章则运用复合材料细观力学的基本理论和经典层板理论对影响细胞壁力学性能的主要因素进行了全面而系统的分析，并为前几章的一些实验结果提供理论上的解释。

Using the 294cc rotary engine, it can influence the maximum rpm and power of the engine output under the terms of using all kinds of length intake. Then it can find out the best length of intake of the rotary engine. In addition, under the terms of space limit of intake, it can influence the maximum rpm and power of the engine output when the intake is forced to limit on a certain length. To install a resonance in the intake system, according to the equation of Helmholtz, it can design the all kinds of size of the resonance. Using to change the volume and geometirc form of the resonance, it can find out the maximum rpm and horsepower of engine output in order to reduce the influence of the variation of engine intake length. Under the verification of the experimental result, this simple device can increase the rpm and horsepower of the rotary engine obviously to achieve the output performance that the engine requires to supply. Such the revisal of intake need the lower cost but it can obtain very obvious efficiency. It is a very feasible way.

藉由一具294cc的飞行器引擎，在使用各种不同长度进气道的条件下，对引擎所能输出的最大转速及马力有一定的影响，藉此找出该具引擎的最佳进气道长度；此外，在进气道因空间限制的前提下，进气道被迫只能局限某个长度以下时，在这种条件下，引擎所能输出的最大转速与马力等相关性能会随之受到影响，在进气系统加装一个共振腔，配合Helmholtz的方程式，设计出各种共振腔各部位的尺寸，利用改变共振腔的体积与几何形状，可以寻求增加引擎转速与输出马力的最大值，藉此降低进气长度变化所带来的影响，在实验结果的验证下，此一简单的装置可以明显的增加引擎转速与马力，以达到对引擎所需的输出性能要求，这样的进气系统修改所需的费用极低，但却可获得很明显的功效，是十分可行的方式。

During numerical simulation,the scale effects of the microstructure of the honeycomb on its structural mechanical performance was studied through changing the scale factor of its unit cell while the volume fraction of the materials remains unchanged.

数值模拟实验中，在材料组分比一定的情况下，通过缩放因子改变单胞尺寸，研究同种蜂窝微结构对结构力学性能影响的尺度效应；同时验证了不同多孔材料微结构构型对结构刚度的影响；在稳态温度载荷的作用下，热变形引起弯曲变形，利用微结构的构型差异和尺度效应共同作用实现结构最大挠度的控制。

Parameterized unit cell of 3-D five-directional braided composites;2. During numerical simulation,the scale effects of the microstructure of the honeycomb on its structural mechanical performance was studied through changing the scale factor of its unit cell while the volume fraction of the materials remains unchanged.

数值模拟实验中，在材料组分比一定的情况下，通过缩放因子改变单胞尺寸，研究同种蜂窝微结构对结构力学性能影响的尺度效应；同时验证了不同多孔材料微结构构型对结构刚度的影响；在稳态温度载荷的作用下，热变形引起弯曲变形，利用微结构的构型差异和尺度效应共同作用实现结构最大挠度的控制。

The reasons of iron ions content overproof in grade Ⅱ desalting water system,such as variation water quality,contamination of regenerant , operation adjustment of pretreatment system and switching operation of bed were discussed.

对二级脱盐水系统中铁离子含量超标的原因，如来水水质发生波动、再生剂受到污染、预处理系统操作调整、床体运行切换等进行了论述。

You were hired to drum up new business, so go and do it.

公司雇你招徕新业务，你就做你的事好了。