中心轴

The bar axis is at an anThe bar axis is at an angle to the central axis and spins around it.gle to the central axis and spins around it.

磁磁棒棒条的轴与中心轴成一角度，并围绕它旋转的轴与中心轴成一角度，并围绕它旋转。。

Use moment of inertia terms to rigid oval ring around the long axis and the short axis of the moment of inertia, and then use orthogonal axis theorem calculation rigid oval ring around the ring with the vertical plane through the central axis and the moment of inertia.

运用转动惯量定义计算出椭圆环刚体绕长轴和短轴的转动惯量，然后用正交轴定理计算椭圆环刚体绕垂直与环平面且通过中心轴的转动惯量。

The results are as follow:(1) In static status, the velocity of jet flow shows a symmetry distribution through central axis of enclosure.

结果表明，腔体静止时，射流速度沿腔体中心轴对称分布，腔体中心轴上的速度最大，两侧流速逐渐减小，近壁处为零；腔体转动时，在哥氏力的作用下，射流中心发生偏转，流场相对于腔体中心轴不再对称分布，腔体中各点处的流速分布随角速度而变化，压电射流角速度传感器利用这一特性敏感角速度。

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。

When a capillary tube, in whose inner hole an optical fiber has been fixed and whose axial deviation amount between an outer peripheral surface of the capillary tube and a core center of an end surface of the optical fiber is 1.5 mum or less, is inserted into the insertion portion of the thin tube and the end surface of the optical fiber is fixed at a position at which a distance of the end surface to a focal point position of the partially spherical lens becomes -40 mum or less, emission light has an emission light bend of 0.2 DEG or less with respect to the center axis of the thin tube.

当将光纤固定在内孔且外周面与光纤的端面的纤芯中心的轴偏移量在1.5μm以内的毛细管插入细管的插入部，并且将光纤的端面固定于部分球面透镜的焦点位置±40μm以内的距离的位置上时，出射光曲率为出射光相对细管中心轴在0.2°以内。

A self-drilling anchor (10) for use in a friable material (1) comprises a body (12) having an axis (13), a flanged rear end (14), a drilling front end (16) and a generally cylindrical portion (18) therebetween having an outer surface (20) with a thread (22) disposed thereon, wherein the body forks, beginning at a predetermined distance from the flanged rear end, into a first leg (24) and a second leg (26), the first leg extending forwardly into a drilling tip (28) and having a generally rearward facing shoulder (30) angled obtusely outwardly with respect to the axis, wherein the body (12) has an axial bore (32) for receiving an elongate fastener (2), the axial bore (32) extending substantially through the flanged end (14) and the generally cylindrical portion (18) and leading to the generally rearward facing shoulder (30), wherein the anchor (10) has a drilling mode wherein the second leg (26) nests behind the generally rearward facing shoulder (30) of the first leg (24), and an anchoring mode wherein the legs are pivoted apart from one another.

一种用于易碎材料(1)中的自攻螺钉(10)，包括：主体(12)，其具有中心轴(13)、带有凸缘的后端部(14)、用于钻孔的前端部(16)和位于所述后端部和前端部之间的通常为圆柱状的部分(18)，所述圆柱状部分(18)的外表面(20)上布置有螺纹(22)，其中主体从距离带有凸缘的后端部的预定的距离处开始分叉为第一腿(24)和第二腿(26)，第一腿向前伸入钻孔尖端(28)，并且具有相对于中心轴向外成钝角的通常面向后的肩部(30)，主体(12)具有容纳细长状紧固件(2)的轴向孔(32)，轴向孔(32)基本延伸穿过带有凸缘的端部(14)和通常为圆柱状的部分(18)，并且通向通常面向后的肩部(30)，螺钉(10)具有钻孔状态和固定状态，在钻孔状态，第二腿(26)套在第一腿(24)的通常面向后的肩部(30)之后，并且在固定状态，腿彼此转动分离。

A circle shear device for cutting holes in sheet metal as in claim 2 wherein said means for synchronous movement of said center shafts includes: a a motion linking mechanism including a plurality of gear cogs, cog belts and a jack shaft; and b said motion linking mechanism includes a hand crank to power the rotation of said center shafts.

一个圈剪切装置切割孔在钣金象索赔2 ，那是说，是指为同步运动的说，中心轴，包括：一）一项议案，连接机制，包括多元化的齿轮cogs ，齿形带和一个千斤顶轴； B ）表示，议案挂钩机制，其中包括一台手摇电力轮换的说，中心轴。

A circle shear device for cutting holes in sheet metal as in claim 2 wherein said means for synchronous movement of said center shafts includes: a a motion linking mechanism including a plurality of gear cogs, cog belts and a jack shaft; and b said motion linking mechanism includes a motor for powered rotation of said center shafts.

一个圈剪切装置切割孔在钣金象索赔2 ，那是说，是指为同步运动的说，中心轴，包括：一）一项议案，连接机制，包括多元化的齿轮cogs ，齿形带和一个千斤顶轴； B ）表示，议案连接机制，包括一个马达驱动旋转的说，中心轴。

A circle shear device for cutting holes in sheet metal as in claim 1 wherein: a said upper center shaft includes a first platform member disposed rotatably connected adjacent a lower end of said upper center shaft for supporting a top surface of said provided metal sheet; b said lower center shaft includes a second platform member disposed rotatably connected adjacent an upper end of said lower center shaft for supporting a bottom surface of said provided metal sheet; and c said upper and lower support platform members engaging top and bottom surfaces of said provided metal sheet to prevent metal sheet movement when said cutter wheels are brought into shearing contact with said provided metal sheet.

一个圈剪切装置切割孔金属板材作为权利要求1 ，其中： A ）表示，上中心轴，包括第一次会员平台弃置rotatably连接相邻较低月底上说，中心轴为支持一个顶面的表示，提供金属板材； B ）表示，较低的中心轴，包括第二个平台会员弃置rotatably连接相邻上月底表示，较低的中心轴为支持一个底部表面的说，提供金属板材； C ）表示，上，下支撑平台成员从事顶部和底部表面的表示，提供金属板，以防止金属板运动时说，刀车轮被带入剪切接触说，提供金属板材。

Central eclipse 中心食 A central solar eclipse occurs when the Moon's shadow axis touches Earth; a central lunar eclipse occurs when the Earth's shadow axis touches the Moon.

当月球的影轴於日食过程中经过地球时，该次日食便为中心食；月食方面，当地球的影轴於月食过程中经过月球时，该次的食就称为中心食。

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。