查询词典 angular aperture

Week 5 Angular momentum of particle and conservation law of angular momentum, angular momentum of rigid body, theorem of angular momentum, conservation law of angular momentum.

第5周 质点的角动量和角动量守恒定律，刚体的角动量、角动量定理、角动量守恒定律。

Measures such as area ratio (the area under the aperture opening divided by the surface area of the aperture wall) and aspect ratio (aperture width divided by stencil thickness) can be used to determine appropriate aperture sizes.

因此，严格控制孔的质量是钢网成功设计的关键。特别是小量沉积材料要求精度高时的高精度要求。

It was illuminated that the width of the centre bright fringe decreased along with the increasing width of the rectangular aperture when the effect of the aperture on the beam couldn't be ignored,however,the width of centre bright fringe step changed with increase of the size of the aperture when the effect could be ignorable,the width of the half maximum intensity of the centre bright fringe decreased along with the accretion of the width of the aperture and then it tends to a constant.

结果表明，当光阑对光束的衍射影响明显时，光束衍射场的中央亮条纹的宽度随着光阑边长的增大而减小；当光阑对光束的衍射影响极小时，中央亮条纹的宽度随着光阑边长的增加而阶跃变化，中央亮条纹强度的半最大值宽度随着光阑边长的增大而减小；当光阑对光束衍射影响极小时，中央亮条纹半最大值宽度趋近于一定值。

The invention provides an insulation pad which is provided with high strength and high friction between a rail cap and a clamp, wherein the pad uses stainless steel as base, two faces of the pad are baked with enamel which is sanded and roughens the surface to brush a layer of silicon rubber, the outline is the same as the inside surface of the rail joint, the aperture on the pad and aperture distance are the same as the aperture and aperture distance of the clamp.

本发明就是制造一个钢轨端头与夹板间的高强度、高摩擦力的绝缘垫板，该垫板的由不锈钢板为基底，双面烤上搪瓷，搪瓷面先经喷砂处理，使其表面粗糙后，刷上一层的硅橡胶，轮廓与钢轨接头内侧表面相同，该垫板上的孔径与孔距与钢轨与夹板的孔径与孔距相同。

And the concept of angular dispersion of diffractive polar angle(the first kind angular dispersion) and angular dispersion of diffractive azimuthal angle (the second kind angular dispersion) are established.

确立了二维平面光栅衍射极角角色散和衍射方位角角色散的概念。

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。

Because the body inertia in ball hitting moment was very small, the angular momentum was mainly affected by angular velocity. In the phase, the average value, largest value and hitting moment value of angular momentum with kick hitting are larger than those with glide hitting. Therefore, the kick hitting could get larger linear and angular momentum.

此阶段平均身体角动量、最大值与击中球瞬间，抬腿击球法三者平均角动量均大於滑步击球法，因此抬腿击球法技术的旋转特质与优势在这可以清楚的看出到，意谓著抬腿击球法打击技术可以使球获得较大的动量与角动量。

The position and size of the monochromator, focusing curvature radii and tilting angles of the germanium focusing monochromator under different different take-off angle, size and divergency of the second collimator and intensity loss due to the use of it were determined. The neutron flux at different wavelength, under different reflection and take-off angle of the monochromator and divergency of the first collimator, were given. The simulation on the aperture used for limiting beam size in front of the sample showed that, smaller the size of the aperture and further the distance from the aperture to the sample, greater the loss of the intensity and more serious the spread of the beam along vertical direction at the sample position which makes the practical sampling volume greater than expected.

用蒙特卡罗模拟方法对中子应力衍射谱仪的设计方案进行了优化研究，提出了一系列可供参考的数据：确定了单色器的位置、尺寸、垂直聚焦单色器在不同起飞角下的聚焦曲率半径和倾角；讨论了第二准直器的尺寸和发散，以及使用第二准直器造成的强度损失；给出了在不同单色器反射面、起飞角、中子波长和第一准直器发散度的情况下样品处的中子注量率，以及多种组合情况下谱仪的分辨率曲线；对限束方孔的尺寸、距离样品远近对强度损失和测量中的影响做了深入研究。

The hard-edge aperture is "moved out" in an complicated optical system, which means to transfer the system with such hard-edge aperture into an optical system with entrance and exit pupils, and the hardedge aperture is taken as an exit pupil so as to find the analytical solution of a light beam.

把硬边光阑从复杂光学系统中"移"出来，即把任意一个含有硬边光阑的复杂光学系统体现到含有入射光瞳和出射光瞳的光学系统中，使硬边光阑的作用转化为出射光瞳的作用，以便求出观察面上的解析解。

This utility model disclosed a dust removal equipment, environmental protection, their characteristics is that, including filters, dust collection equipment and negative pressure ventilation machines, referred to the vertical filter settings are arranged in descending sequence multi-aperture filter, its Set large aperture filters connected at one end of inlet pipe, set a small aperture at one end of filters connected through the vacuum exhaust fan out of the wind pipe, dust collection equipment installed in the bottom of each layer filters.

本实用新型公开了一种环保除尘设备，其特征在于，包括过滤器、集尘装置和负压抽风机，所述过滤器内垂直设置有多层孔径依次从大到小排列的过滤网，其设置有大孔径过滤网的一端连接进风管，设置有小孔径过滤网的一端通过负压抽风机连接出风管，集尘装置设置在每层过滤网的下端。

Fostering the concept of multi-culture firmly and mastering the development of advanced culture correctly are conductive to resisting terrorism, separatism of nationalities and ultraism of religion, which is of great academic theoretical, immediate and profound historical si...

牢固树立多元文化的理念和正确把握先进文化的发展方向，有助于在世界范围内自觉地抵制恐怖主义，民族分裂主义和宗教极端主义。不仅具有重大的学术理论意义，而且也具有重大的现实意义和深远的历史意义。

But if anyone walks in the night, he stumbles, because the light is not in him.

11：10 若在黑夜行走，就必碰跌，因为那光不在他里面。