曲率半径

On the basis of OCM, segmentation based on curvature radium is presented in the paper, in which curvature radium is calculated using parametric-surface fitting, and detecting edge points is realized from orthogonal direction, which ensure the integrality of edge points. Since the data is organized by cross-line in OCM, a new arithmetic, Double-direction Angle Difference arithmetic, is brought forward, which can pick up edge points more quickly.

物体的表面一般由多个曲面相交组成，要建立完整的几何模型，需要对测量数据进行区域分割——区分不同曲面的数据，现有的区域分割大多是对单视图的图像式测量数据进行的，但完整的CAD模型需要联合多个视图产生，本文在上面提出的三维正交模型的基础上，提出了三种区域分割方法：第一种方法是基于曲率半径的数据分区方法，通过二次参数曲面拟合计算局部曲率半径，从正交的多个方向进行检测，保证了边点提取的完整性。

Consider the circle that is tangent to the curve at and has the same curvature there. Its center will lie on the concave side of the curve. This circle is called the circle of curvature. Its radius is the radius of curvature, and

在点处的曲线的法线上，在凹的一侧取一点，使得，以为圆心，半径为的圆叫做曲线在点处的曲率圆，曲率圆的圆心叫做曲线在点处的曲率中心，曲率圆的半径叫做曲线在点处的曲率半径。

The said Martinez stretcher comprises concave spherical reflecting lens, plane reflecting lens and grating. The said compressor comprises plane reflecting lens, inner right angle reflecting lens and grating, which is characterized by the following: the grating fringe density of the stretcher is larger than that of the compressor.

所述的马丁内兹展宽器由凹球面反射镜、平面反射镜和光栅组成；所述的压缩器由平面反射镜、内直角形反射镜和光栅组成，其特征在于，展宽器的光栅条纹密度大于压缩器的光栅条纹密度；展宽器中的凹球面反射镜曲率半径位0.9～1.2米，光栅距凹球面反射镜的位置为凹球面反射镜曲率半径的1/3～1/2。

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 iris radius of 60 (93 eye) patients with early pupillary block primary angle closure glaucoma was measured with this method, it showed:(1) there was a statistically significant difference in iris radius between the patients with early stage primary pupillary block angle closure glaucoma and the normal subjucts (53 cases 106 eye) with the age matched group (P.01),(2) it is proved with the stepwise discriminatory analysis that the iris radius-the most significant bio-anatomic parameter of the anterior segment is usefull to diagnose early primary pupillary block angle closure glaucoma by stepwise discriminatory analysis.

本研究用此测量法测量了60例93只眼早期原发性瞳孔阻滞性闭角型青光眼的虹膜曲率半径，发现：（1）早期原发性瞳孔阻滞性闭角型青光眼患者的虹膜曲率半径小于同年龄正常人（53例106眼）的虹膜曲率半径，其差异具有显著性统计学意义（P.01）；（2）经多因素逐步判别分析证明本研究所提出的活体眼前节解剖学测量参数——虹膜曲率半径有助于原发性瞳孔阻滞性闭角型青光眼早期诊断。

The equations of the curvature, curvature radius, main curvature and main curvature radius on hypocycloid抯 and epicycloid抯 theoretical tooth shape and practical tooth profile are deduced respectively.

根据微分几何知识，分别推导出内、外摆线理论齿形和实际齿廓的曲率、曲率半径、主曲率及主曲率半径的方程式，并绘制了内、外摆线理论齿形和实际齿廓曲线及理论齿形的曲率半径变化曲线。

We can regard the narrow gauge mine car and the level man car as a evolution of the inclined-shaft man car ,the computing methods of the radius of curvature between them are same,so the study of the passing radius of curvature for the inclined-shaft man car is of great significance,which will produce far-reaching effect for design,test,research and development of the man car and the gauge car.

矿用窄轨矿车和平巷人车可以看成是斜井人车的一种演变，其曲率半径的取值方法同斜井人车的曲率半径取值方法基本上是一致的，所以斜井人车所能通过的曲率半径的取值方法的研究有着重要的意义，对人车和窄轨矿车的设计、检测检验、研发也有着深远的影响。

In this paper an analysis has been made to some regions of magnetosphere, including the Nightside, Cusp and Duskside. By applying the Curvature Radius Method to the magnetic field data measured by four satellites of Cluster, the geometrical structure of Magnetic Field Lines, including the curvature radius, directions of curvature and normal of the osculating planes of the Magnetic Field Lines have been investigated.

本文采用曲率半径分析方法，结合Cluster立体探测的相关知识和背景，利用Cluster立体探测的优势，通过对Cluster 2001年的立体探测数据的研究，分析了磁层各区域的磁力线结构，包括背阳面、Cusp区以及昏侧，得出各区域中磁力线的曲率半径大小，曲率矢量以及磁力线密切面的法线矢量的方向。

Some primary metering grooves with different curvature radiuses and geometrical dimensions were designed,and the hydraulic characteristics of them were all tested Based on the experiment results, different flow characteristics of them were obtained The great differences between the experimental results and the conventional theoretical predictions were found by the comparison between them Under the condition of this experiment, the critical Reynolds is 1000～1200, and is diminished as the decrease of th...

为了在设计层板发汗冷却推力室时选择合适的一次调节通道，对不同曲率半径、不同几何尺寸的一次调节通道进行了流阻试验，得出了不同几何尺寸的一次调节通道的流动特性。试验结果与经典的层流理论计算结果之间存在较大的差异。试验表明，一次调节通道的临界雷诺数随曲率半径的减小而减小，摩阻系数随曲率半径的减小而增加，并得出了相应条件下的一次调节通道摩阻系数的修正关系式，在层流范围内能较好地反映一次调节通道的流阻特性

The anticlastic curvature caused by bending is 1700 times as long as the sagittal curvature, and the incident angle error is only 2.2 μrad. The Von Mize stress on the bender is about 806 MPa. When Beryllium-Cu is selected as the material of the bender, the linear relationship between the curvature of crystal in 0.57~1.72 m and the driving forces in 8~2.67 N is obtained.

优化后晶体因压弯产生的鞍形曲率半径约为弧矢曲率半径的1700倍，造成的人射角误差为2.2μrad；压弯装置上的最大平均应力约为800MPa，并由此确定了以铍青铜作为压弯机构的材料，晶体的曲率半径为0.57~1.72m和驱动力为8~2.67N时的线性关系。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。