量计的

A novel direction of arrival and polarization estimation of electromagnetic vector sensors mounted on the airframe is proposed based on biquaternion. The signal processing model for EM-sensor mounted on the airframe is made by biquaternion and then the eigenvalue decomposition of spectral matrix is obtained by means of the EVD of its quaternion adjoint matrix. The memory requirement for data is reduced, and more accurate estimation result is gotten by deducing the stronger orthogonality constraint between the sin- gal and noise subspaces on the field of biquaternion. The performance of the new algorithm is confirmed through numerical examples.

针对机载电磁矢量传感器阵列DOA和极化参数估计问题，提出了一种基于复四元数估计方法，该算法利用四元数建立机载电磁矢量传感器阵列信号处理模型，然后利用四元数联合矩阵的特征分解得到阵列数据相关矩阵的特征分解，一方面使得计算过程中数据的贮存量大大减少，另一方面通过推导得到信号子空间和噪声子空间在四元数域上的正交性从而使DOA和极化参数佑计的精度更高，仿真证实了本算法的有效性。

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。

Induction watt-hour meter is the principle of electromagnetic induction to voltage, current, phase into a magnetic moment, and promote aluminum rotating disk, the disk axis gear-driven drive device degrees of drum rotation, that is, the process of turning is the cumulative amount of time to process.

感应式电能表是采用电磁感应的原理把电压、电流、相位转变为磁力矩，推动铝制圆盘转动，圆盘的轴带动齿轮驱动计度器的鼓轮转动，转动的过程即是时间量累积的过程。

The residual gas pressure in an electron tube can be measured when the tube itself is operated as a hot cathode ionization gauge.Usually,its sensitivity K is determined by the method of gauge calibration.In this paper,author try to determine the sensitivity K by ca- lculation.The formulae for this purpose have be found out,and are used for both plate and cylindrical electrode systems.

把电子管接成热阴极电离计的工作形式，用来测量管内残气压强时，其灵敏度如何计算的问题在本文中作了讨论，给出了平板形电极系统和圆柱形电极系统的灵敏度解析式，对式中各量的计算作了详细介绍；并指出四极管中电子在电离区的平均渡越次数的表示式与三极管中的完全不同。

Next, the following points are emphasized:(1) The design of photoelectric conversion preamplifier circuit. In order to improve the measurement accuracy of luminometer and ensure linear relationship of the photoelectric, operational amplifiers is designed as current-voltage converter form, on the one hand, it is available to zero-load effect; on the other hand, short-circuit current can be transformed into a voltage volume through the feedback resistor, it is equivalent to voltage drop flowed through a load resistor on the actual effect.

其次，本文重点做了以下工作：(1)光电转换前置放大电路的设计：为了提高照度计的测量准确度，确保光电间的线性关系，本设计把运算放大器接成电流电压变换器的形式，一方面可得到零负载效应；另一方面，短路电流通过反馈电阻变成电压量，实际效果相当于流过一个负载电阻形成的压降。

The universality of application of helicoidal surfaces in the engineering, the importance of their performance in the certain field and the non-replaceability of their functions in the specified mechanical systems have resulted in that the technology of measurement for helicoidal surfaces has been a critical research project in the field of dimensional measurements.

螺旋曲面在工程中应用的广泛性、在一定领域中其性能的关键性以及在特定机械系统中其功能的不可替代性，决定了螺旋曲面测量技术历来是几何量计测技术中一项重要研究课题。

The results indicate that the heteronuclear bond energies are greater than homonuclear bond energies.

用示差扫描量计、X光衍射以及透射电镜研究了非晶铝合金的晶化行为，结果表明，非晶铝合金的晶化经历了初晶型晶化和剩余非晶的多重型晶化，整个晶化过程可相应地分为第一和第二晶化阶段。

Small deformation in the rubber parts within the preload can be approximately negligible, but the large amount of local deformation, rubber non-linear characteristic curve of a stronger, more obvious the role of preload.

在橡胶件的小变形范围内，预紧力可以近似忽略不计，但变形量大的地方，橡胶件的特性曲线非线性较强，预紧力的作用较为明显。

This technique is to make a device to instead those transmitters and reduce the need in pressure gauges. Using the electronic valve and flexible tube to construct the control panel is effective to connect the single pressure gauge with every sensor point in ventilation duct.

利用软管将欲量测之管段的压力导引到控制箱内，并将所有导引来的静压分别安装在一组并联的各电磁阀上，再将所有的动压分别安装在另一组并联的各电磁阀上，而该两组并联电磁阀的底部各安装一根连通管连结至单一差压计的高低压两端，并利用控制组件切换各电磁阀的启闭以达到多点压力监测切换的目的。

This technique is to make a device to instead those transmitters and reduce the need in pressure gauges. Using the electronic valve and flexible tube to construct the control panel is effective to connect the single pressure gauge with every sensor point in ventilation duct.

利用软管将欲量测之管段的压力导引到控制箱内，并将所有导引来的静压分别安装在一组并联的各电磁阀上，再将所有的动压分别安装在另一组并联的各电磁阀上，而该两组并联电磁阀的底部各安装一根连通管连结至单一差压计的高低压两端，并利用控制元件切换各电磁阀的启闭以达到多点压力监测切换的目的。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。