角

A unicorn 独角兽(from Latin unus 'one' and cornu 'horn') is a mythological creature.

尽管现在对独角兽较为流行的描述有时会是一匹在前额长角的马。

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。

There are many ways to calculate GPS satellite azimuth and elevation, but the precision is low. A new method to decide GPS satellite position using the broadcast ephemeris is presented, the way to checkup the precision is also given, and some research are made to analysis the error feature of the position which is calculated by the broadcast ephemeris as well, the results show the error is periodic.

GPS卫星高度角、方位角计算方法众多，但精度低；针对这点，提出了一种利用广播星历计算卫星高度角、方位角的方法，对该方法能够达到的精度提出了鉴定的途径，并分析了利用广播星历计算卫星高度角以及方位角的误差特点，结果表明利用广播星历计算的卫星高度角、方位角呈现出周期性变化的规律。

A new method to decide GPS satellite position using the broadcast ephemeris is presented, the way to checkup the precision is also given, and some research are made to analysis the error feature of the position which is calculated hy the broadcast ephemeris as well, the results show the error is periodic.

GPS卫星高度角、方位角计算方法众多，但精度低；针对这点，提出了一种利用广播星历计算卫星高度角、方位角的方法，对该方法能够达到的精度提出了鉴定的途径，并分析了利用广播星历计算卫星高度角以及方位角的误差特点，结果表明利用广播星历计算的卫星高度角、方位角呈现出周期性变化的规律。

Result showed that the epidermis dominant the morphogenesis changes. Mesenchymal is subdominant.β-catenin expression begin from horny placode epidermis stage and go up increasingly to peak value and maintain in hair follicle. The range of mesenchymal change is less.

结果表明，牦牛角的形态发生按照角基毛囊和角质外鞘发生与否分为5个阶段：角原基前期(Ed≤60)表皮增厚，无毛囊发生；角原基中期(Ed60~140)表皮持续增厚，有少量毛囊发生；角原基后期(Ed140~250)表皮变薄，大量毛囊发生；肉角期(≤0.5 a)真皮乳头发生；成角期(≥0.5 a)形成角质外鞘。

All the angles whose terminal edges are the same as the terminal of an angle α form the set S=｛β｜β＝α＋k·360°,k∈Z｝,i.e.,any angle whose terminal edge is the same of αcan always be represented by αplus intergral number of perigons .

所有与角α终边相同的角，连同角α在内，可构成一个集合S＝｛β｜β＝α＋k·360°，k∈Z｝，即任一与角α终边相同的角，都可以表示成角α与整数个周角的和。

The main technical parameters which decide the movement speed are the ankle angle of the support leg, the horizontal velocity, the hip angle and the support leg's hip joint angle, knee angle and the former support distance at the moment of contact, and the latter leg's hip joint angle, the upper arm's movement scope, the support leg's knee angle, the swing knee's angle, the support leg's hip angle at landing phase, and the ankle angle, the support leg's hip angle, the swing velocity of the former leg, the hip angle of the swing leg and the angle of the landing knee at the pushing phase.

我国优秀男子百米途中跑着地瞬间对动作速度起主要贡献的技术指标是：支撑腿的踝关节角、着地瞬间脚的水平速度、大腿夹角及支撑腿的髋角、膝角和前支撑距离；垂直缓冲瞬间是摆动腿髋关节角、上臂前摆幅度、支撑腿和摆动腿膝关节角、支撑腿髋关节角；后蹬瞬间是踝关节角、支撑腿髋关节角、大腿前摆角速度、摆动腿的髋角及支撑腿膝角。

Hunting Narwhals 猎杀独角鲸 Medieval royalty coveted the Arctic whale's long ivory tusk.

中世纪就让皇家贵族垂涎的北极独角鲸长着如同。。。

The Company is threaded sheath, also known as snail wire sets, silk sets of braces, sheathed the thread protection and repair products, professional products and service providers, dedicated to this product for many years, the existing public and Britain, the United States system of standards products, complete specifications, professional services, welcomed the thread slip teeth or want to improve product strength thread calls the user communications to provide stainless steel screws, screws imports, 12.9 screws, screw English, US-made screws, thread sheath, steel screws, wire sets, jacket, inner hexagon screws, fasteners, cup head screws Hexagon, Hexagon screw Ping Cup, Cup Round Hexagon screws, machine-processed rice screws, stop screw, stainless steel set screws tight, stainless steel screws Hexagon, English outside the hexagon screws, hexagon screws outside the US-made, stainless steel outer hexagonal screws, self tapping screws, machine wire, etc.

本公司是螺纹护套，也称钢丝螺套，丝套，牙套，护套的螺纹保护与修复产品的专业产品供应与服务商，致力于此产品多年，现有公、英、美制等标准的产品，规格齐全，专业服务，欢迎在螺纹滑牙或想提高产品螺纹强度的各用户来电来函，提供不锈钢螺丝，进口螺丝，12.9级螺丝，英制螺丝，美制螺丝，螺纹护套，钢丝螺丝，丝套，护套，内六角螺丝，紧固件，内六角杯头螺丝，内六角平杯螺丝，内六角圆杯螺丝，机米螺丝，止付螺丝，不锈钢紧定螺丝，不锈钢内六角螺丝，英制外六角螺丝，美制外六角螺丝，不锈钢外六角螺丝，自攻螺丝，机丝等，主要产品：不锈钢螺丝，不锈钢机丝，不锈钢自攻螺钉，不锈钢螺母，不锈钢六角螺丝，不锈钢内六角螺丝，316不锈钢螺丝，不锈钢杯头螺丝，不锈钢机米螺丝，不锈钢自攻螺丝，不锈钢法兰，英制不锈钢螺丝，美制不锈钢螺丝，慧鱼的化学锚栓，喜力得的建筑锚栓，其它国内的化学类锚栓，钻尾螺丝，自钻螺丝，平爆，钢结构螺丝等，专业建筑紧固件供商，有慧鱼的化学锚栓，喜力得的建筑锚栓，其它国内的化学类锚栓，钻尾螺丝，自钻螺丝，平爆，钢结构螺丝，扭剪螺丝，钢构螺丝，墙板钉，自攻钉，膨胀螺丝。

This paper presents the Machining Tool geometry of the former flank, the main flank, flank, the main cutting edge, Under the cutting edge tip cutting plane, the main section, the former Kok, horn, wedge angle edge angle, pointed knife, the blade angle, vice horn, Under the Frontier concept, the concept of cutting consumption, and the general circumstances of their choice method for processing slender shaft. cast iron materials, aluminum, stainless steel, rubber materials, plexiglass material, cloth bakelite materials, high temperature alloys, aluminum-magnesium alloy, hardened steel, the typical trapezoidal thread, the thread Triangle, Speaking at the trapezoidal screw thread pitch of the Tool geometry of the selection methods and cutting the amount of cutting fluids reasonable choice.

本文介绍了在机械加工中车刀几何角度中的前刀面、主后刀面、后刀面、主切削刃、副切削刃刀尖切削平面、主截面、前角、后角、楔角主偏角、刀尖角、刃倾角、副后角、副前角的概念、切削用量的概念、以及一般情况下的它们的选择方法，进行加工细长轴、铸铁材料、铝合金、不锈钢、橡胶材料、有机玻璃材料、夹布胶木材料、高温合金、铝镁合金、淬火钢、典型梯形螺纹、三角螺纹、特在螺距的梯形螺纹等的车刀几何角度的选取方法切削用量及切削液的合理选择。

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。