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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。
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By using the group-chain, the wavefunctions of the 4f〓 configuration for RE ions are also expressed as linear combinations of group-chain basis functions in Butler's irreducible representation notation. The matrix elements of the CF Hamiltonian then are calculated by means of the Wigner-Eckart theorem and factorization lemma of the jm factors. Before the CF level fitting, a point-charge calculation of the conventional CF parameters B〓 has been performed by means of the lattice-sum technique from the known crystal structure data. The corresponding parameters in the group-chain are calculated by the conversion relationship between two schemes that proved identical in essence, which are usually used as initial values in the fit to the experimental levels. The ratios of the same k-value CF parameters are suggested as the constraint conditions in the fit, in order to utilize fully the symmetry distortion degree of the studied system.
利用群链理论,属稀土离子4f〓组态的波函数表示为以不可约表示标记的群链基波函数的线性组合;借助Wigner-Eckart定理和2jm和3jm因子的分解定律计算了晶场哈密顿的矩阵元;根据点电荷模型和已知晶体结构数据,利用点阵求和技术计算得到传统晶场参数B〓初值,相应的非传统形式的群链参数初值则由两种方案下的转换关系求得;这些初值通常作为非线性拟合晶场能级计算的初值,系统的对称性畸变信息则反映在以同阶晶场参数的比值作为能级拟合的约束条件。
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Secondly, the platform of IPTV set-top box named DM6446 is introduced, and then the AVS video coding standard which is implemented as the video coding standard of IPTV is introduced. The kernel architecture, peripheral devices of DM6446 and the key technique of AVS video coding such as transformation, quantization, intra-prediction, inter-prediction, interpolation, and loop filter is introduced in detail. Thirdly, the system procedures of set-top box which are implemented on the ARM side of DM6446 are introduced in detail. This part focuses on the demultiplex of audio and video data, the design of data interface, the playback of audio and video, and the communication between ARM and DSP. Fourthly, the loop filter algorithm of AVS video coding standard is introduced in full detail, and the optimized procedures of the algorithm on the DSP side of DM6446 are introduced, and then the optimized results are presented. Fifthly, the thesis introduces and analyzes the state-of-art technique of deblocking filter, and proposes a deblocking method, and then the results of proposed method are given. Finally, summarize of this thesis and further development is given.
首先对IPTV技术、视频编解码技术以及去块滤波技术做了简要介绍;然后介绍了IPTV机顶盒的实现平台DM6446,并介绍了该处理器的外围接口和内核结构,同时介绍了作为本IPTV系统视频标准的AVS第二部分视频标准,以及该标准中变换量化、帧内预测、帧间预测、插值和环路滤波等多个模块的算法;接着,详细介绍了机顶盒系统相应程序在DM6446 ARM核上的实现,重点介绍了音视频系统码流的解复用、数据接口设计、音视频的播放以及ARM核与DSP核之间的通信;然后,详细介绍了AVS视频标准中环路滤波算法及该算法在DM6446 C64+内核上的优化,并给出优化结果;然后对去块滤波算法进行了研究并提出了一种环路滤波方案,同时给出了此方案的实验结果;最后总结了本文的工作,并提出了可以改进的方向。
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The main research contents and results are given as follows:(1) Principles and characteristics of different types of polarization controllers are analyzed, the compare of the difference of these polarization controllers are discussed based on them, drawn a conclusion that the polarization controller which based on squeezing fiber and has variable delay quantity are suitable for high speed optical communication system.(2) The reset principle of the typical four channel polarization controller which is based on squeezing fiber is analyzed, and the design of its concrete reset scheme is given based on them. The reset process and the corresponding operation list are given in detail.(3) The systematical experiment is made when the typical four channel polarization controller is put into the PMD compensator. The experiment result showed that the channel which needs reset can efficiently return to the mean place, and the effect of reset was good, it didn't cause any badness infection on PMD compensation.(4) A new type optical signal time-domain depolarizer is given, and a new PMD compensate method is given based on it.
由此得出延迟量可变型光纤挤压型偏振控制器适用于高速光通信系统的结论;(2)具体分析了典型的四通道光纤挤压型偏振控制器的复位原理,并在此基础上对其进行了具体复位方案的设计,给出了各种情况下的详细复位流程和相应的复位操作列表;(3)将四通道光纤挤压型偏振控制器应用于偏振模色散补偿器中进行系统实验,实验结果表明,需要复位的通道能有效地回到中间值,复位效果良好,且复位未对PMD补偿产生不良影响;(4)设计了一种新型的光信号时域退偏器,并基于该退偏器提出了一种新型的偏振模色散补偿方法。
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The changes of the electron transverse momentum are the basic factors of electron and photon scattering, and their differential scattering sections are decreased with increasing of the quantity of photons which are active with an electron at the same time, and they are quickly decreased with the increasing of the inelastic scattering composition, but their change are slower than that in the situation dominated by laser field.
电子横向动量的变化是引起电子和光子散射的根本原因,其微分散射截面随与一个电子同时作用的光子数的增大而减小,随散射非弹性成分的增大而迅速减小,但比激光场中的情况来得慢一些。
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The validities of amplitude features and their extraction method suitable in high-frequency SAR image are analyzed when they are used in UWB SAR image. An extraction approach of amplitude feature based on target contour is presented, and the corresponding effective amplitude features are proposed. The old dihedral angle model is analyzed and improved. The approach of azimuthal feature extraction is proposed based on the conclusion of the improved dihedral angle model. The problems, which appear when the common change detection methods are used to extract the change feature based on ROI, are analyzed. And a robust and feasible extraction approach is presented.
分析了适于高频SAR图像的幅度特征及其提取方法用于UWB SAR图像时的有效性,提出了基于目标轮廓的幅度特征提取方法及相应的适用幅度特征;分析了已有二面角模型在建模过程中存在的问题并进行了改进建模,基于改进二面角模型结论提出了方位向特征提取方法;分析了常用变化检测方法用于提取ROI变化特征时存在的问题,提出了一种稳健可行的变化特征提取方法。
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Kate Dillon: I think it happens to everybody at some point where you feel one way about yourself and that your initial…your intuition about who you are, is that you are a good person, that you are beautiful, that you are strong, that you are capable.
凯特·狄龙:我觉得每个人都会那么一个时候,对自己抱有一种看法,而你对自己最初最直觉的看法是"你是个好人","你是漂亮的","你很强壮","你很有能力"这样的。
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Based on electro-characteristic and double electric layers models, directional mechanisms of soy protein molecular are analyzed for the first time on DC heating condition. After the main factors which effect soy protein gels transparency and strength being studied on DC heating condition, the different affects on soy protein gels transparency and strength by DC heating and water bath heating are analyzed and compared, and the transparent mechanisms of soy protein gels are further explored. In addition to temperature action as water bath heating, DC heating is added as electric field directional action. As a results, heating rate is increased. Directional range degrees of soy protein molecules are raised. These advantage the increase of soy protein gels transparency and strength. Microstructures of soy protein gels forming on DC heating condition are observed by SEM and the results showed that ordered structure of transparent soy protein gels on DC heating condition is more ordered than that of transparent soy protein gels on water bath heating condition.
首次从大豆蛋白的电特性和双电层模型上分析了直流电加热条件下,大豆蛋白分子定向的机理;通过对直流电加热条件下影响大豆蛋白凝胶透明性和强度主要因素的研究,分析和比较了直流电加热与水浴加热对大豆蛋白凝胶透明性和凝胶强度的不同影响,又进一步探讨了大豆蛋白凝胶透明的机理;直流电加热除了水浴加热中的温度作用以外,又增加了直流电场的定向作用,提高了加热速率,提高了大豆蛋白分子定向排列的程度,有利于蛋白质凝胶透明性和强度的提高;利用SEM对电场下大豆蛋白凝胶微观结构的观察,进一步证明了直流电加热比水浴加热形成的透明大豆蛋白凝胶微观结构具有更高的有序性。
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Of Salon he shared with effervescence ,Australian consumers are demanding the best Champagne and they are not intimidated by the price(Salon 1996 RRP $650), people are more conscious of what they are drinking and they want something different and they are prepared to pay for it.
说到沙龙酒,他兴奋地说:澳洲消费者要求的最佳香槟,并不怕价格高(1996年沙龙零售价650澳元),人们更关注的是他们喝的是什么酒,他们想要的东西不同,他们是愿意为它花钱。
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Now people attach importance to the cleaning of silicon grinded wafer. There are a lot of carborundums and silicon powders on the wafer surface because grinded wafer are grinded by carborundum and corresponding depth are remove in the sequence of grinding. After grinding there are plenty of carborundums and silicon powders enchase in the damaged layers. So there are many difficulties in later processes.
半导体硅单晶衬底加工工业中最受重视是硅磨片的清洗,由于硅磨片是用金刚砂研磨的,研磨过程中又要去除相应的厚度,所以刚加工的磨片表面附着着大量的金刚砂和研磨下来的硅粉,而且还有相当一部分金刚砂和硅粉镶嵌到破损层里面,这给后续的清洗工作带来了困难。
- 相关中文对照歌词
- You Are What You Are (Beautiful)
- Some Things Just Are The Way They Are
- Honey, Are You Straight Or Are You Blind?
- We Are The Way We Are
- Men Are From Mars, Women Are From Hell
- You Are, You Are
- You Are What You Are
- When You Are Who You Are
- You Are / You Are Lord
- We Are Who We Are
- 推荐网络例句
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On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.
另一方面,更重要的是由于城市住房是一种异质性产品。
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Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.
气候直方图是将所收集的降水量测定值,分为几个相等的区间作为横轴,并将各区间内所测定值依所出现的次数累积而成的面积,用柱子排起来的图形,也叫做柱状图。
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You rap, you know we are not so good at rapping, huh?
你唱吧,你也知道我们并不那么擅长说唱,对吧?