无失真

This paper is devoted to the development of a new meshless method based on a new approximation of shape function.

主要工作是推导了一种基于新的形函数形式的无网格方法。由于目前的无网格方法中，紧支域的大小和形状不同直接影响整体场函数的分布，有时会造成计算结果的严重失真。

Chaper 3 is general description of ADA encryption. Chapter 4 deals with the transform domain encryption. Includes the element of perfect and quasi-perfect transform domain encryption, and presents two type new schemes. Chapter 5 deals with asynchronous ADA encryption. Extends the general theory and model of asynchronous ADA scrambling, and introduces two type phase-distortion-free a synchronous ADA schemes. Chapter 6 is about new direction of ADA encryption. Includes TASI scrambling, transform domain dummy insertion scrambling, noise coving scrambling and other multi-dimension ADA scrambling, and proposes an adaptive dummy spectrum insertion asynchronous scrambling and a new adaptive noise-coving DFT scrambling algorithm. Chapter 7 is on permutation key. presents part results on permutation features, selecting criterion and constructing method. Chapter 8 introduces the hard and software design of a common ADA encryption/decryption system, and presents the experimental results on several proposed ADA encryption schemes.

第一章为绪论；第二章为语声信号、及其处理基础；第三章为模数模加密的一般描述；第四章为变换域加密研究，包括变换域加密机理，变换域完善与准完善保密研究，提出两种新的变换域加密方案；第五章为异步模数模加密研究，扩充了异步模数模加密的一般理论，介绍了两种新的无相位失真异步加密方案的原理与实现方法；第六章对模数模加密新方向：TASI应用途径、变换域伪谱插空置乱、噪声掩盖、多维置乱加密的原理和方法进行介绍，提出了自适应伪频插空异步模数模置乱算法与自适应DFT系数噪声掩盖置乱新算法；第七章为置换密钥性质、筛选准则以及构造方法研究的部分结果；第八章介绍了通用模数模加/解密实验系统的硬件、软件研制概况，并给出了几种加密方法的实验结果。

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。

In data space, multi-stage anti-aliasing digital filters are designed on the basis of the Nyquist sampling theorem and the minimax criterion to ensure that the observational data are sampled and stored without distortion.

在数存空间内，依据奈奎斯特定理和最大误差最小化的原则，设计多级抗混叠数字滤波器，使实测数据经过滤波器后，达到无失真抽样与存储的目的。

According to the invention, a method for increasing quality of an enhanced output signal to approximate an undistorted sound signal is disclosed.

根据本发明，公开了把增强输出信号的质量提高到接近无失真声音信号的方法。

C. electric parameters measurement. The means and conditions to reestablish the signal without distortion are also given. At last, this paper discusses the theoretical basis for power, RMS and harmonics phase measurements of power system directly from the Harr wavelet matrix transform data associated with each sampling voltage and current element pair.

本文针对电力系统特点，分析了非均匀采样的数字频谱结构及非均匀采样周期信号的数字谱表达式，并讨论了非均匀采样对交流电量参数测量的影响，给出了非均匀采样无失真恢复信号的方法和条件。

So tranditional memoryless predistortion can not compensate memory nonlinear distortion of PA.

因此，无记忆预失真器不能校正放大器的记忆非线性失真。

On the basis of the statistical characterestics of satellite meteorological infrared cloud charts this paper presents a coding algorithm of "Sub sampling+Modified JPEG+Image enlarging",realizing a compression ratio of 50∶1～100∶1, with the PSNR of 35～40dB and visually unperceptible distortion.

依据GMS卫星红外气象云图的统计特性，提出了一种&亚抽样＋修改的JPEG＋图象放大&的静止图象编码方法，使有失真压缩比在50∶1至100∶1时，恢复图象峰值信噪比在35dB～40dB之间，主观质量无视觉可觉察到的失真。

In this thesis. Interband coding techniques are investigated for effective compression of multiband images such as color images and hyperspectral images. A multiband lossless compression system based on context matching prediction schemes is proposed. The observation is that the interband correlation in multiband images is usually greater than the intraband.

中文摘要此论文探讨有效率的压缩彩色影像及卫星影像类型的多频带影像利用频带间预测编码的技术，提出一种基於频带间内文比对预测方式的多频带影像无失真压缩系统，观察结果显示多频带影像邻近频带相互之间冗余特性大於频带内。

This probe suits the measurement of micro gas flow,which conforms with the theory of the differential\|pressure orifice flow meter,and it is designed light and handy and used conveniently.

该探头适用微流量气体流量的测量，采用了差压式孔板流量计的原理，设计轻巧，使用方便，能够进行远距离无失真传输，方便了现场测试。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。