时轴

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。

Meanwhile, performance predictions, and analysis of the head and efficiency with or without front guide impeller were done under different flow rate.

最后，对不同流量下，有、无前置导轮时轴流泵的扬程、效率进行性能预测并分析。

Division of Anatomy is primarily dedicated to teaching and research in anatomy including vertebrate morphogenesis, oxygen regulation of placental development, neural coding in the hypothalamus, neurogenesis, brain mechanisms of emotion, animal models for schizophrenia, the notochord and vertebral patterning, axon guidance in the developing brain, brain information processing in cerebellar cortex.

解剖学系主要致力于解剖学的教学与研究，研究领域包括脊椎动物形态发生，胎盘发育的氧调整，丘脑下部的神经编码，神经发生，情绪情感的脑机制，神经分裂症动物模型，脊索和脊椎模型，大脑发育时轴索控制，小脑皮层中的脑信息加工等。

. As a result, the oil film character of tilting pad would be changed into that of the finite arc cylindrical bush, with the bearing centre , the axle journal centre , the eccentricity and the angle of displacement .

假定开始时轴颈是没有运动的，如图1所示，瓦块圆弧中心、轴颈中心以及瓦块支点处于同一直线上，轴颈中心和瓦块中心间距离定义为原始偏心。

The influences of the nonlinear clearance-excitation fluid force of turborotor on the dynamic behaviors of rotor's axial rub-impact are insignificant. The only effect is the appearances, in the axial response, of the higher order superharmonic components of even-time working frequency at low rotating speeds.

分析表明，非线性涡轮叶尖间隙流体激励力对转子轴向碰摩的非线性特性影响不很明显，只是在低转速时轴向振动碰摩响应中会出现更高阶的偶数倍频的超谐波成分。

The coupling could make the washing machine change the work state between washing mode and dehydrating mode. Synchromesh gear that is located on the flange section and connection gear that is located at the external circle surface of the down side of the flange section is formed on coupling. The compression spring is installed on the top of the coupling and effects to the coupling to make it always moving downward. The feature is diameter of the terminal section of the compression spring is smaller that of the compression spring installation groove on the flange of the coupling.

其包括联轴器和压缩弹簧，联轴器可使洗衣机在洗涤模式和脱水模式间转换，其上形成有同步齿轮和连接齿轮，同步齿轮位于凸缘部上并在与联轴器限制件的齿轮相啮合时能使洗衣机进行洗涤；连接齿轮位于凸缘部下侧的外圆周面上并在与外连接器上的齿轮相啮合时能使洗衣机进行脱水；压缩弹簧安装在联轴器的上端并作用于联轴器，使其始终向下移动，其特征在于：所述的压缩弹簧的终端部直径较联轴器凸缘部上的压缩弹簧安装槽直径小。

RESULTS The degenerative changes of nerve ending in Meissner's corpuscles were observed after 1 month of denervation, and the basic structure of the corpuscles had no obvious changes. After 3 months, the axons of corpuscles were disappeared, and the volume of corpuscles was shrunk. The basic structure of nerves was disappeared, and the lemmocyte and neurolemma plate were changed after 5 months.

结果 失神经1个月时触觉小体内的神经末梢已有溃变，触觉小体的基本结构无明显改变；3个月时轴突消失，触觉小体的体积开始萎缩；5个月时神经结构消失，膜细胞及其膜板亦开始改变；8个月时触觉小体内胶原纤维含量逐渐增多；12个月时触觉小体内膜结构与膜间基质完全消失，被胶原纤维代替。

Electrophysciological indexes: in the experimental group ,the tardy rate of induced motorius action potential ,recovery rates of the amplitude of compound muscle action potential and twitch tension and tetanic tension of triceps surae muscle ,were significantly higher than in the control group.(4) Compared with the control group ,the triceps surae muscle wet weight was significantly greater in the experimental group.(5) histomorphological indexes: the count of myelinated nerve fibers ,diameter of regenerated axon,thickness of nerve myelin sheath and area of capillary were much more in the experimental group than in the control group.(6) observation of ultrastructure with the transmission election microscope: more abundant organella and maturer myelin sheath lay in the injured peripheral nerve of the experimental group, while not lay in the control group.

分别在术后第2、4、6周时进行各项指标的检测，结果发现：（1）实验组SD大鼠在整个实验过程中，其精神、毛发、体重，运动灵活性等一般情况优于对照组；（2）实验组的坐骨神经功能指数恢复率显著优于对照组，P＜0.01；（3）神经电生理指标：实验组运动神经诱发电位潜伏期的延迟率显著优于对照组，P＜0.05；复合肌肉动作电位振幅的恢复率显著高于对照组，两组比较第2周时P＜0.01，第4、6周时，P＜0.05；小腿三头肌单收缩力和强直收缩力的恢复率实验组显著高于对照组，P＜0.01；（4）小腿三头肌湿重的恢复率，第2、4周时实验组高于对照组，差异非常显著，P＜0.01；第6周时，差异仍显著，P＜0.05；（5）组织形态学指标：有髓神经轴突计数、再生轴突直径的恢复率，毛细血管面积，实验组均显著大于对照组，P＜0.01、P＜0.05、P＜0.001；实验组髓鞘厚度的恢复率也显著高于对照组，第2周时P＜0.01，第4、6周时，P＜0.05；（6）透射电镜超微结构观察：实验组再生轴突中细胞器丰富，髓鞘结构成熟，神经再生情况优于对照组。

Under the condition of poor effect of surmounting "statics with pitch-resistant",domestic scholar have made new concept —deviation control with high WOB .

大钻压动力防斜技术增加钻压引起钻柱屈曲，保特钻柱涡动，有井斜时使钻柱产生周期性变化的轴向附加力，无井斜时轴向附加力消失，克服了传统防斜技术中吊打的缺点，提高了钻井速度，达到了解放钻压的目的。

All the indexes were tested in 2 -. 4 .. 6 weeks of operative intervals respectively. Results:(1) The general observation in the experimental group ,such as spirit, hair, body weight and activity ,was superior to that in the control group.(2) The recovery rate of sciatic nerve functional index (SF1) was statistically significantly higher in the experimental group than in the control group .(3) electrophysciological indexes: m the experimental group ,the tardy rate of induced motorius action potential ,recovery rates of the amplitude of compound muscle action potential and twitch tension and tetanic tension of triceps surae muscle ,were significantly higher than in the control group.(4) Compared with the control group ,the triceps surae muscle wet weight was significantly greater in the experimental group.(5) histomorphological indexes: the count of myelinated nerve fibers ,diameter of regenerated axon, thickness of nerve myelin sheath and area of capillary were much more in the experimental group than in the control group.(6) observation of ultrastructure with the transmission election microscope: more abundant organell a and maturer myelin sheath lay in the injured peripheral nerve of the experimental group, while not lay in the control group.

分别在木后第2、4、6周时进行各项指标的检测，结果发现：（1）实验组SD大鼠在整个实验过程中，其精神、毛发、体重，运动灵活性等一般情况优于对照组；（2）实验组的坐骨神经功能指数恢复率显著优于对照组，P＜0.01；（3）神经电生理指标：实验组运动神经诱发电位潜伏期的延迟率显著优于对照组，P＜0.05；复合肌肉动作电位振幅的恢复率显著高于对照组，两组比较第2周时P＜0.01，第4、6周时，P＜0.05；小腿三头肌单收缩力和强直收缩力的恢复率实验组显著高于对照组，P＜0.01；（4）小腿三头肌湿重的恢复率，第2、4周时实验组高于对照组，差异非常显著，P＜0.01；第6周时，差异仍显著，P＜0.05；（5）组织形态学指标：有髓种经轴突计数、再生轴突直径的恢复率，毛细血管面积，实验组均显著大于对照组，P＜0.01、P＜0.05、P＜0.001；实验组髓鞘厚度的恢复率也显著高于对照组，第2周时P＜0.01，第4、6周时，P＜0.05；（6）透射电镜超微结构观察：实验组再生轴突中细胞器丰富，髓鞘结构成熟，神经再生情况优于对照纽。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失