聚焦轴

We calculate the field distribution near focus of an aplanatic system for incident ASPBs with different polarization orders and initial azimuthal angles, and based on the simulation results, we find some unique focusing properties of the beams, such as ever on-axis energy null, strong longitudinal field, and flowerlike intensity distribution at focus.

计算了不同偏振级次和偏振初始角的轴对称偏振光束当入射到无球差系统时在焦点附近的场分布，通过这些模拟结果，发现了该光束一些独特的聚焦特性，例如光轴强度始终为零、具有较强的轴向光场以及在焦点附近场呈现花瓣状分布等。

The measuring device is structured by including a He-Ne laser; a beam expander, a soft aperture slot and a off-axis parabolic mirror to be measured are arranged in turn along the direction of the emergent laser beam direction of the He-Ne laser; a standard cross hair and a micro objective are arranged in turn on the direction of the reflected beam of the off-axis parabolic mirror; the micro objective is arranged on the focus of the off-axis parabolic mirror; the focus is imaged on an area array CCD; the output end of the area array CCD is connected with a computer; the off-axis parabolic mirror is fixed on a five-dimensional electric adjusting frame.

一种离轴抛物面镜点聚焦能力测定装置和测定方法，测定装置的构成包括：一台He-Ne激光器，沿该He-Ne激光出射激光束方向依次设置扩束器、软边光阑和待测的离轴抛物面镜，在该离轴抛物面镜的反射光束方向依次设置标准叉丝和显微物镜，该显微物镜位于所述的离轴抛物面镜的焦点，所述的焦点成像于面阵CCD上，该面阵CCD的输出端接计算机，所述的离轴抛物面镜固定在一五维电动调整架上。

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 computer separately connects and controls the I/O end and A/D converter; the I/O end connects and controls the X, Y axis driving circuit and the semiconductor laser; the X, Y axis step-by-step driving circuit connects and controls the X, Y step-by-step electrical machines to control the dimensional platform; the beam of the semiconductor laser passes through the focusing drawtube with 0.1mm diameter to form the facula with the diameter less than 0.1mm; the facula irradiates on the detector surface of the XY dimensional displacement platform to produce the corresponding electric signals; the detector surface connects the A/D converter through the amplifier; the electrical signal is amplified and is converted into the data signal by the A/D converter and is sent to the computer for processing.

由计算机分别连接并控制I/O端口和A/D转换器，I/O端口分别连接并控制X、Y轴步进电机驱动电路和半导体激光器，X、Y轴步进电机驱动电路分别连接并控制X、Y轴步进电机，从而控制二维位移平台，半导体激光器的光束经过设有直径0.1mm小孔的聚焦镜筒形成＜0.1mm直径的光斑，光斑照射于设在XY二维位移平台上的探测器表面使其产生响应的电信号，探测器表面经放大器连接A/D转换器，电信号经放大器放大后，由A/D转换器转换为数据信号送计算机处理。

The camera is flicker-free, offers a backlight compensation function, and features a three-axis mount.

图像不闪动，提供背光压缩功能，并配置三轴底座，聚焦调试简单，可以在几分钟内实现聚焦，并提供3年售后维护。

Based on the traits of the aspherical lens, the sunlight was focused on a very small spot, and then it was transferred into a plastic fiber by an aspherical lens and a selfoc lens. A formula for calculating the optimal length of selfoc lens is presented. The optimal assembly of the aspherical lens and selfoc lens was implemented by the aid of this formula. Therefore, sunlight is coupled into a plastic fiber efficiently.

根据非球面透镜垂轴球差小的特点把太阳光会聚到很小的光点，再利用长度约为1/4节距的自聚焦透镜改变光线的数值孔径使其满足光纤的数值孔径，通过一个计算公式来计算最佳的自聚焦透镜长度，实现非球面透镜和自聚焦透镜的最佳组合，把太阳光以较高的耦合效率耦合进塑料光纤。

We present a new method for alignment optical axis and axis of rotation in laser direct writing system using reflection of plane grating.

提出一种光栅反射对准法：在极坐标激光直写系统中利用光栅反射聚焦光斑来校准光轴和工件台的转动轴；被光栅反射的聚焦光斑成像在CCD上。

Focusing properties of elegant cosh square Gaussian and Sinh square Gaussian beams through a thin lens are studied in detail. And intensity distribution on the axis and focusing intensity distribution are analyzed. Also focal shift of Sinh square Gaussian beams are studied.

详细研究了复宗量双曲余弦平方-高斯光束和双曲正弦平方-高斯光束通过薄透镜时的聚焦特性，分析了光束的轴上光强分布和聚焦场的光强分布，讨论了双曲正弦平方-高斯光束的焦移。

This study used the pick-up head from the commercial DVD-ROM as the basis for optical path, and drilled a 2mm hole on the focusing object lens. After combined with the design of a beams plitter, the laser beam source of the two DVD formed two in-line laser beams. One laser beam passed through the undrilled part, and focused on the surface of the object to be tested, in order to measure the displacement variance of the surface.

於三自由光学测探头的研制上，则将DVD 探头之聚焦物镜做一2mm 的穿孔，於搭配一分光镜的设计后，使个DVD 的光源形成同轴光束，将其中ㄧ光束经由聚焦物镜未穿孔部分，聚焦於待测物表面，用以测待测物表面的位移变化，另一光束则穿透过聚焦物镜穿孔部分，直接将光束投射至待测物表面，作为待测物表面之个角的变化测。

In this research, the micro optical pick-up head is composed of a micro optical bench and a focusing lens mounted on a two-axis actuator. The study of focusing lenses is the major topic in this thesis.

在本研究中，微光学读取头是由微光学平台及固定在双轴致动器的聚焦透镜所组成的，其中的聚焦透镜正是本论文研究的主要方向。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。