小圈

We had a diet of crawfish and beignets.

我们吃了很多小龙虾和甜甜圈。

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。

In the minimal coupling model of the electron and photon electromagnetic interaction,we have a precise calculation on the differential cross section of Compton scattering with electron renormalized chain propagator,and obtain the accurate result.

采用电子与光子电磁相互作用最小耦合模型，对电子重整化链图传播下Compton散射微分截面作了严格解析计算，获得精确理论结果；并将该计算结果与电子树图和重整化单圈图传播下Compton散射微分截面作对比分析，获得了有关辐射修正的重要信息。

At present, the wireless devices in general to bring the whole antenna, omni-directional radio antenna to the antenna axis, was "donut"-shaped radiation field; directional antenna is highly directional, in the small angle of radiation is totally outside the scope of signals ; the use of removable external antenna equipment can gain antenna, the antenna can not increase in the case of radiated power to increase communication distance.

目前的无线设备一般自带全向天线，全向天线电波以天线为轴，呈"面包圈"状向外辐射；定向天线具有极强的方向性，在小角度的辐射范围外是完全没有信号的；使用可拆卸天线的设备可以外接增益天线，可以在不增加天线辐射功率的情况下增加通讯距离。

He had besides the things before mentioned, twelve marbles, part of a jews-harp, a piece of blue bottle-glass to look through, a spool cannon, a key that wouldn't unlock anything, a fragment of chalk, a glass stopper of a decanter, a tin soldier, a couple of tadpoles, six fire-crackers, a kitten with only one eye, a brass door-knob, a dog-collar-but no dog-the handle of a knife, four pieces of orange-peel, and a dilapidated old window sash.

除了以上提到的那些玩意以外，还有十二颗石头子；一只破口琴；一块可以透视的蓝玻璃片；一门线轴做的大炮；一把什么锁也不开的钥匙；一截粉笔；一个大酒瓶塞子；一个锡皮做的小兵；一对蝌蚪；六个鞭炮；一只独眼小猫；一个门上的铜把手；一根拴狗的颈圈——却没有狗——一个刀把；四片桔子皮；还有一个破旧的窗框。

Powder metallurgy gears include: bevel gear, dual-gear, gear box gears, planetary gears, ring gear, rack, sector gears, bevel gears, spur gears, sun gear, helical gear, gear shaft, flat gears, spur gears, double layer gear, synchronous pulley, helical gear, sprocket, ratchet, multi-gears, micro-gear, small modulus gear, special gear, differential bevel gear, reducer gears, variable speed gear motor, all kinds of precision gears.

粉末冶金齿轮包括：伞齿轮、双联齿轮、齿轮箱齿轮、行星齿轮、齿圈、齿条、扇形齿轮、锥齿轮、直齿轮、太阳齿轮、斜齿轮、齿轴、平齿轮、正齿轮、双层齿轮、同步轮、皮带轮、螺旋齿轮、链轮、棘轮、多层齿轮、微型齿轮、小模数齿轮、异形齿轮、差速伞齿轮、减速机齿轮、变速电机齿轮、各类精密传动齿轮。

He asked for a doughnut and a small coffee.

他点了一个甜甜圈和小杯咖啡。

The specific capacitance of the ACNT electrode was calculated at 16F/g before the MnO2 film modification, and then it increased to 330 F/g after the MnO2 film deposition due to the special Faradic capacitance of MnO2 With scaning for 200 cycles, there's a litter change for its cyclic voltammogram curve, indicating the good reversible and capacitive property for the MnO2-ACNTs composite.

直立碳纳米管电极的比电容为16 F/g，在碳纳米管表面沉积上二氧化锰修饰层后，此复合材料电极的比电容增大至330 F/g，比电容量大幅提升近20倍。同时扫描200圈后，直立碳纳米管与二氧化锰复合材料的循环伏安曲线变化很小，说明其具有相当好的循环寿命和电容稳定性能。

And small spring replaces equal circle so as to enhance its floatability and sealed performance .

特点：辅助密封圈与旋转环压制成一体，小弹簧代替紧圈，浮动性强，密封性能更为可靠，弹簧分左右旋向。

The plant with good growth is in big lotus below can wear unripe circuit small lotus, in addition annual spring the red that end still can take out similar bracketplant from phyllome bottom walks along a bine, front walking along a bine is long have lotus shape flocculus clump.

发育良好的植株在大莲座下面会着生一圈小莲座，此外每年的春末还会从叶丛下部抽出类似吊兰的红色走茎，走茎前端长有莲座状小叶丛。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。