试验过的

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。

The effect of Al on microstructure evolution of a hypereutectoid steel(0.97%C) during deformation of undercooled austenite was investigated by hot uniaxial compression tests.

利用Gleeble 1500热模拟试验机进行单轴热压缩实验，研究了合金元素Al对过共析钢缓冷相变和过冷奥氏体动态相变组织的影响。

Understand the thyroid hormone inhibition test,result analysis and clinical application of Perchlorate suppression test.

了解甲状腺激素抑制试验、过氯酸钾释放试验的结果分析和临床应用。

In order to study moisturizing effect of glycerin,petrolatum and common hand-skin care cream,the friction of the natural skin on the back of hand(without the use of hand-skin care products) as well as that after using of care products was measured by using of a micro- tribometer .

为研究甘油、凡士林和普通护手霜3类产品的保湿性能，在微观摩擦试验机上对男女手背自然皮肤及使用过3类护手霜后的摩擦因数进行了试验。

Methods: To process Schick test in1450 children who were random checked in Fuzhou city, and compare result of Schick test before vaccination in260 children without vaccinating triple vaccine.

在市辖区、中随机抽查1450名儿童进行锡克氏试验，并对206名未接种过三联疫苗的婴幼儿，进行接种前后锡克氏对比试验。

solid propellant rocket engine ; success-failure ; reliability growth test ; Poisson distribution ; max-min stopping rule

试验次数太多，会造成不必要的浪费；试验次数过少，可能无法发现一些潜在的重要故障模

Spine specimens were fixed to the biomechanical elongation tester (Shimazu AGS-J, Japan) with the upper clipping at the vertebra dentata, T1 and T12 vertebra, the lower clipping at the superior part of thigh bone. Under the different states, keeping or removing psoas muscle, the extended stress (N/mm^2 )of different segments of spine at the flexed and extended positions of hip joint were measured respectively.

上端十字头分别夹枢椎、第1胸椎和第12胸椎，下端十字头夹股骨上部；分别作有腰大肌状态下和切断腰大肌状态下，股髋自屈曲位到过伸带动脊柱自屈曲位到过伸位拉伸试验，测定两种不同状态下脊柱各节段的伸展应力。

The first were by de Saussure, in 1679. Having put an infusorium in a drop of water, he saw it divide under his eye.

第一个涉足这方面试验的人是 Saussure ，他在1679年时做过一个试验，将纤毛虫放入一滴水中，用肉眼就能观察到它的分裂过程。

Adult patients have tested the ketogenic diet for a variety of disorders other than epilepsy, and one of them told me that it was too "soft and slimy" for her taste—although she nevertheless stuck with it for a time.

对成年患者，曾进行过除癫痫之外多种疾病的生酮饮食试验。其中一位告诉过我，那东西对她来说口感&太软太黏糊&——尽管如此，她仍然坚持了一阵子。

The test results show that the crispest HAZ occurs in the process of welding of the 14MnNbq steel on the first heat circulation submerged welding overheat zone and the second heat circulation submerged welding overheat zone plus the not entirely re crystallized zone. The 14MnNbq steel has a tendency of being crisper due to overheat than the SM490C steel is. In order to ensure the toughness of the welding HAZ′s, the welding wire capacity should be properly controlled during welding.

由试验结果表明，14MnNbq钢焊接HAZ最脆区出现在一次热循环的埋弧焊过热区及二次热循环的埋弧焊过热区+不完全重结晶区；14MnNbq钢比SM490C钢有更强的过热脆化倾向，为确保焊接热影响区韧性，焊接时应适当控制焊接线能量。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。