参数变换

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 variation regularity is discussed that the stress, temperature and deformation of the current-carrying annular plate are altered with the variation of loaded electromagnetic parameters. According to the relation between the deflection of annular plate and the parameters, it is proved that the deformation and stress can be controlled by changing the electromagnetic and mechanics parameters.

变换电磁参量，讨论了载流环形薄板应力、温度及变形随外加电磁参量的变化规律；根据圆环形板的挠度与参量之间的变化规律，并通过实例证实了可以通过改变电、磁、力场的参数来实现对板壳的应力、应变状态的控制。

First, this paper, in the field of intrinsic geometry, studies the geometric problems on garment design, as well as applies the frame and semi-geodesic coordinates to prove the fundamental theorem of being a developable surface.

文中首先在内在几何学的层次上，研究了服装设计所涉及的几何学问题，应用标架与半测地坐标方法证明了曲面成为可展面的基本定理，研究了可展面的分类及其性质，考虑到服装三维几何造型的需要，证明了组合式可展面各组成片相切连接条件的命题，作为构造可展面的理论依据，证明了单参数平面族的包络面必为可展面的命题，在此基础上发展出服装几何造型的"刮大白"方法以及相关的三种构造可展面的解析方法。3D→2D的变换是三维服装CAD的重要内容之一，其几何学实质是曲面的定长映射，文中总结了定长映射即可展面在平面上展开的基本准则，在这一准则的指导下，结合服装设计与相关领域的要求，讨论了可展面在平面上展开的解析方法与数字方法，上述内容确立了服装设计几何学的基本框架。

On the base of the single-diameter laser-scanned measuring technology, a double direction laser-scanned measuring system is presented. Which combinate the laser-scanned measuring technology with special optical system. In the system, the collimation semiconductor laser-scanned beam scanning two perpendiculars direct of one plane of the measured workpiece at the same time is made. The beams with the dimension information of two perpendiculars direct are processed by the scanning receive system, the high-speed photoelectric transition and electronic data process. Two measured results of the diametric directs and ellipse tolerance,etc, parameter, of the turning workpiece on the same plane are obtained by non-contact automatic measurement. The problem of non-contact measurement of two perpendiculars direct of one plane of turning workpiece is settled. It processes many peculiarities, such as high speed, high accuracy and non-contact automatic measurement, etc.

在单向激光扫描检测技术的基础之上，提出了一种双向激光扫描检测系统，其采用激光扫描检测技术与特殊光学系统相结合，用准直半导体激光扫描光束对被测工件径向某一截面的两个相互垂直方向同时扫描，经扫描接收光学系统、高速光电变换、电子学系统和微机数据处理系统，对将携带有垂直方向被测量信息的光束进行处理，实现了回转体工件同一截面两个垂直方向的径向尺寸和椭圆度等参数的非接触自动测量，解决了同时非接触测量回转体零件同一截面两个径向尺寸的难题，它具有高速，高精度和非接触自动测量等特点。

In the system , the collimation semiconductor laser - scanned beam scanning two perpendiculars direct of one plane of the measured workpiece at the same time is made . the beams with the dimension information of two perpendiculars direct are processed by the scanning receive system , the high - speed photoelectric transition and electronic data process . two measured results of the diametric directs and ellipse tolerance , etc , parameter , of the turning workpiece on the same plane are obtained by non - contact automatic measurement

在单向激光扫描检测技术的基础之上，提出了一种双向激光扫描检测系统，其采用激光扫描检测技术与特殊光学系统相结合，用准直半导体激光扫描光束对被测工件径向某一截面的两个相互垂直方向同时扫描，经扫描接收光学系统、高速光电变换、电子学系统和微机数据处理系统，对将携带有垂直方向被测量信息的光束进行处理，实现了回转体工件同一截面两个垂直方向的径向尺寸和椭圆度等参数的非接触自动测量，解决了同时非接触测量回转体零件同一截面两个径向尺寸的难题，它具有高速，高精度和非接触自动测量等特点。

Based on the diffeomorphism transformation and Lyapunov direct method, controllers for the reference yaw angle and the reference speed are designed.

首先应用微分同胚等效变换和Lyapunov直接法设计参考航向和参考速度，然后对船舶模型参数不确定的操纵环路和推进环路分别设计神经网络稳定自适应控制器跟踪参考航向和参考速度，并对外界风浪流干扰进行自适应补偿。

Area coordinates and general Duffycoordinates are employed to transform the singular integrals of the Time-Domain Electric Field Integral Equation into non-singular integrals, which can be accurately and efficiently evaluated by dividing the transformed domain of integration into sub-domains.

摘要该文首先利用参数坐标和广义Duffy坐标变换将时域电场积分方程的奇异性积分转换成非奇异性积分，然后根据时间基函数的特点将该积分转换成可以快速精确计算的分区域积分。

The problem,"the monitoring parameters in time domain are of great variability and are sensitive to noise", may also be solved in this study.

运用连续小波变换方法对手术中采集的体感诱发电位分析处理，提取信号在时频域的三个新的特征参数。

Signal analysis;parabola parameter spline curve;Empirical Mode Decomposition;Intrinsic Mode Function;Hilbert transform

信号分析；抛物参数样条曲线；经验模态分解；固有模态函数；希尔伯特变换

Results The equivalent matrix equation is derived by the matrix transformation method.The parameter iterative algorithm and the sufficient and necessary conditions for the convergence are given.

结果基于矩阵变换方法导出了矩阵方程的等价形式，并构造出参数迭代格式，得到了格式收敛的充要条件。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。