不均匀

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。

Shim current calculationWhen shim coils are excited by appropriate current, they can generate correcting magnetic field to compensate the imaging magnetic field unhomogeneity. Based on the indirect calculation method, we proposed a novel iterative optimization algorithm to calculate shim current. Because there is a direct proportion relationship between FID signal and magnetic field homogeneity, we use the intensity of FID signal as feedback information to the calculation. Shim current can be worked out in less than 3 minutes. This satisfied the requirement that active shimming should be performed in real time.

5匀场电流计算对匀场线圈施加适当的电流后才能产生校正磁场消除成像磁场的非均匀分量，本文在匀场电流间接计算方法的基础上，利用磁共振成像原理中磁场均匀性与系统FID信号强度成正比的关系提出了一种电流迭代优化算法，将系统FID信号强度的变化作为反馈信息，能够快速计算出匀场电流对成像磁场进行补偿校正，平均耗时不到三分钟，满足磁共振成像系统对有源匀场的实时性要求。

Basic operators of color image morphology are established.The result of the experiment demonstrates that the color vector order has good property.The algorithm of color image morphology based on this order can better keep the peripheral information and hue of the image and has the strong point of unnecessity of exchanging between different color spaces.

实验结果表明提出的颜色向量序性能良好，建立在该向量序上的彩色图像形态学算法能够较好的保持图像的边缘信息和色调，并且亮度均匀，与原图像相比对比度均匀增强，重构开算法的实验结果比原文献中方法有了较大的改进；具有不需要在不同的颜色空间之间转换的优点。

There are several reasons for this: injection technology (usually featured by 128-cavity moulds) makes it extremely difficult to maintain uniform temperatures, to ensure uniform distribution of plastic etc. So outgoing pieces are not all the same and, because bottling lines are ever-faster, any downtimes caused by cap quality problems can inflict economic damages on the producer that are much higher than the unit cost of the individual cap.

这是有：注射技术的若干（通常是由在128腔模具）的原因使得很难保持均匀的温度，以确保即将离任件，所以不是所有的一样的，塑料等均匀分布，因为瓶装生产线是不断更快，任何停工时间造成的帽子质量问题可以对生产造成的是比个人帽的单位成本高得多的经济损失。

The results indicated that,during MV drying,moisture distribution in wood was relatively uniform,without an obvious moisture content gradient along the direction of thickness of wood.Moisture distribution in wood was more uniform in the last period of drying.Above Fiber Saturation Point,the movement of moisture through wood was assumed to be permeable movement of free water and vapor under the action of pressure gradient;below FSP,moisture existing in vapor form in wood moved in response to a pressure gradient.Moisture transfer caused by heat diffusion and a moisture content gradient could be neglected.

研究结果表明：在微波真空干燥过程中，木材内部的含水率分布比较均匀，在厚度方向没有明显的整体性含水率梯度，特别是在干燥的后期，木材内部的含水率分布更加均匀；当含水率在纤维饱和点以上时，木材中的自由水和水蒸气在压力梯度的作用下以渗透流的形式在木材内部迁移；当含水率在FSP以下时，木材中的水分在压力梯度的作用下以水蒸气的形式向木材表面迁移；因热扩散、含水率梯度引起的水分迁移可以忽略不计。

From the import of a sheet-fed business card printing and membership card making machine the average price of $ 6.4 million, the largest quantity of imported or sky, a souvenir sheet off, and a souvenir sheet of multi-color offset press, a small offset printing presses in the fendback of multicolored imported, play an important role to play.

从不不进口一台单弛纸制卡和会员卡制作机的均匀代价为64不一丑元，不不进口量最不小的还是四闭、差闭、残弛和超残弛的众色胶印机，众色小胶印机在盖住不不进口方背，起到次给的功用。

In order to produce lightweight cashmere and wool products of fashion with low cost and high added-value,a appropriate mixing ratio of water-soluble PVA fiber,cashmere and high-counts wool is selected,oil pick-up and moisture of blended top wool are strictly controlled,yarn twist and weaving tightness are carefully designed,and the vinylon dissolution process is optimized.

结果表明：水溶性PVA纤维所占混纺比例越高，可纺纱线密度就越低，但其所占比例过高则会造成坯布紧度及织造难度增大，退维后织物中纱线条干均匀度差，织物结构松烂；水溶性PVA纤维所占比例过小，则不易混合均匀，可纺纱线密度降低得少，达不到轻薄产品的要求。

The technique problems such as quick charging of high voltage capacitor, uniform discharge in high pressure large aperture zone, uniform flow of high pressure gas, and laser resonator, high energy pulse output and high repetition pulse output, were solved by applications of ultraviolet preionization, two-circuit series and parallel discharge structure of graphite Ernst electrode, folded resonator that embodies super-thin water-cooled non-deforming mirror, closed circle direct cooling system of double loop and high-voltage high-current switch power supply.

采用紫外预电离双路Ernst石墨电极串并联放电结构、超薄水冷不变形镜折叠腔、双回路直冷式封闭循环流动系统和高压大电流快脉冲开关电源等技术，解决了高功率高压电容充电、高气压大体积均匀辉光放电、高气压高速均匀流场、激光谐振腔和高脉冲能量、高重复频率脉冲激光输出等技术难题。

The steppe landscape is dominant but not apparent in its patch and area, and the percentage of the original vegetation of Stipa bungeana steppe is very low in the study area, which is apparently characterized by human disturbance. The diversity and evenness of patches in the study area are higher than those of the steppe landscape area, and the fragmentation and the isolation of the steppe are the highest. The landscape shapes of artificial arbor woods and cultivated lands are the simplest, and the landscape shapes of classical steppe and artificial shrub are in an instable stage.

结果表明：(1)草原景观在其斑块数和面积上虽然仍居首要地位，但其优势并不十分明显，而且该区原生植被本氏针茅草原只占很小的比重，呈现出非常明显的人类干扰特征；(2)研究区斑块的多样性程度和均匀度较高，而面积的多样性程度和均匀度较低，同时，典型草原的景观破碎度最大，景观分离度也最大；(3)景观形态上，人工乔木林和耕地的景观形态最为简单，典型草原和人工灌丛这2种景观类型还处于很不稳定的阶段。

When the compounding ratio of aliphatic resin, aromatic resin, unsaturated hydroxy acid ester, and metallic soap blends was 3:3:1:3, the homogenizing-dispersing agent THD was produced.

结果表明，当脂肪烃树脂、芳香烃树脂、不饱和醇酸酯及皂类混合物之间配比为3：3：1：3时制得的均匀分散剂THD可以改善胶料混合的均匀性，提高炭黑的分散效果，并且节约混炼能耗，增加了胶料的耐老化性能，对硫化胶的力学性能影响不大。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。