小角

In this paper we have point out the error of principle formula quoted by all literatures at home and abroad to measure the refractive angle and the method of V-prism, derive from beginning the right formula of measuring refractive index by the method of minimum deviation angle and the method of V-prism.

本文指出了测量光学材料折射率的最小偏向角法和V棱镜法国内外所有文献的原理公式误差，重新推导了最小偏向角法和V棱镜法测量折射率的正确公式。基于最小偏向角法用精密测角仅可以获得±3×10-6的折射率的测量精度，然而，这些文献沿用经典的测量原理公式却具有-4×10－4数量级的原理公式误差，因此导致错误的测量结果。

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。

Shenzhen with Fu, Main: electroplating equipment, electroplating equipment supply all kinds of fittings fittings: Cross handle frames, plastic 65 tooth gear, 21 tooth plastic gear, plastic dual-V-Block, hexagonal screws 3 hours, 4 minutes plum screws, roller big axis, kegs of portable batteries, portable pail handle, hand-held drum gear hexagonal plastic punching: advantages: plastic punch hexagonal cylinder shape, the use of electrical conductivity, and fast access to medicine.

双V型胶座。深圳同富华，主营：电镀设备的各种配件供应电镀设备配件：十字柄架，65齿胶齿轮，21齿胶齿轮，双V型胶座，六角螺丝3分，梅花螺丝4分，滚筒大轴心，手提式小桶芯，手提小桶柄，手提齿轮六角滚筒胶板冲孔：优点：胶板冲孔六角滚筒成型后，使用时导电好，药水出入快。

In the normal rats (n=5、6), CGRP-LI were mainly present in small and some medium-sized neurons and the primary afferent fibers and ter- minals in laminae Ⅰ,Ⅱ,Ⅴ,Ⅹ and Lissauer's tract of the spinal cord; GAL- and SP-LI were mainly present in small neurons and the superficial layers of the dorsal horn. After the adjuvant injection both CGRP-and SP-LI were in- creased corresponding to the development of arthritis. On day 2, CGRP-and SP-LI were moderately increased in laminae Ⅰ,Ⅱ and the posterior commis- sure of the spinal cord and small neurons in DRG, while SP was obviously in- creased in the superficial layers and DRG. On day 14, CGRP-LI were marked- ly enhanced in the above regions with the development of polyarthritis. Some- times many strongly stained long fibers could be seen in the posteriot commis- sure.

在DRG中，CGRP主要分布于小和中等神经元之中，SP和GAL主要分布于小神经元之中；2、注入弗氏完全佐剂（含冻干结核菌0.5mg）后第2天动物（各5~6例）产生具有明显红、肿、热、痛和痛敏的急性关节炎，免疫组化实验观察到注射侧脊髓背角和DRG中CGRP-和SP-LI明显增加；在佐剂后第14天，动物患肢肿胀、痛敏和自发痛均进一步加重，部分动物健肢也出现红肿，产生多发性关节炎时，脊髓背角浅层和DRG中CGRP-和SP-LI增加更为明显，并且在灰质后联合中可见许多深染的CGRP-LI长纤维；在佐剂后第21和28天，随着佐剂性关节炎的逐渐恢复，脊髓背角和DRG中CGRP-和SP-LI也接近正常。

Circular and catenary always represent the shapes of minor principal stress soil arch between two parallel walls, but which shape should be used in the calculation of active earth pressure on two parallel walls remains disputed. Considering fully developed wall friction or partially developed wall friction, circular and catenary, the two shapes of minor principal stress soil arch between two parallel walls are theoretically analyzed. According to the shapes of soil arch, the coefficients of earth pressure corresponding to different angle of internal friction and that of wall friction are obtained, and the formula of active earth pressure on two parallel walls is derived.

鉴于计算平行墙间侧土压力时关于土体小主应力拱形的选择尚存在争议，考虑墙土摩擦角充分发挥和部分发挥两种情况，对平行墙间土体小主应力圆弧拱和悬链线拱分别进行了分析，得到了对应于不同内摩擦角和墙土摩擦角的侧上压力系数，以及平行墙间侧上压力的理论公式。

In addition, the computational evaluations indicate that the heat transfer enhancement of delta winglet for aligned tube bank heat exchanger is more significant than that for staggered tube bank heat exchanger, the heat transfer enhancement of delta winglet with the attack angle of 45° is more obvious than that of 30°; the delta winglet with the attack angle of 45° leads to an increase in pressure drop, while the delta winglet with the attack angle of 30° results in a slight decrease.

另外计算还发现：三角形小翼对顺排换热器的强化换热效果好于对叉排换热器的强化；冲角为45°的三角形小翼强化换热效果好于冲角为30°的三角形小翼；冲角为45°的三角形小翼导致空气压降提高，而冲角为30°的三角形小翼则可使压降有所减小。

But the value of H angle is smaller than class I malocclusion . Campared with the data of class II malocclusion , for class III malocclusion there are significant differences in LsL , LiL , lower lip angle of inclination , mentolabial sulcus angle , H angle , upper lower lip angle , Ns-Sn-Ls . For class III malocclusion the value of LsL is shoter than class II malocclusion , but the value of LiL is longer than class II malocclusion . The value of lower lip angle of inclination , mentolabial sulcus angle , upper lower lip angle is bigger than class II malocclusion .

安氏Ⅱ类错合患者与安氏Ⅲ类错合患者相比，在上唇长、下唇长、上唇倾角、下唇倾角、颏唇沟角、H角、上下唇角和软组织轮廓这些指标有显著性差异；安氏Ⅱ类错合患者的上唇长比安氏Ⅲ类错合患者的长、安氏Ⅱ类错合患者的下唇长比安氏Ⅲ类错合患者的短；安氏Ⅱ类错合患者的上唇倾角和H角比安氏Ⅲ类错合患者的大，安氏Ⅱ类错合患者的下唇倾角、颏唇沟角和上下唇角比安氏Ⅲ类错合患者的小。

This paper also makes a experimental study of the regularities of the outstripping machining in aspects of machine tool, cutting tool, cutting conditions and so on, and points out that the outstripping phenomenon occurs on the following conditions: the machine tool with high precision, the PCD cutting tool with small clearance and lay angle, the small installation angle, the small feed rate and the cutting lubricant with good properties, and that the cutting speed and the depth of cut have no effects on the outstripping machining.

本文还从机床、刀具和切削条件等方面对超越性加工的规律进行了实验研究，指出超越性加工现象是在如下条件下产生的：较高精度的机床、后角和刃磨纹理角较小的PCD刀具、较小的安装角和较小的进给量以及冷却润滑性能良好的切削液，而切削速度和切削深度对超越性加工几乎没有影响。

In order to overcome the difficulties faced on analytically deriving the equation for describing the samll angle light scattering patterns from anisotropic objects with arbitrarily director configurations, a Fast Fourior Transformation algorithm for the calculation of SALS patterns from the anisotropic objects immersed in an isotropic matrix has been developed.

用快速傅里叶变换计算方法( Fast Fourier Transformation，FFT)直接获得高分子材料中介观有序结构小角激光光散射图案，从而对实验获得的球晶和液晶液滴的 SALS图案进行结构预测。

Once you're on the other side of the lake, kill small-horned Kerubims.

当你在湖的另一边时，杀小角Kerubim。

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。