不变的

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。

"Wisdom lies neither in fixity nor in change, but in the dialectic between the two."

费译：智慧不在不变，也不在恒变，而在不变和恒变之间的辩证之中。

Innovation achievements of this dissertation are mainly in the content and the method, namely: presents the content of EAP thoroughly and systematically; reviews the cost, utility and empirical studies of EAP; investigates the cost and utility of EAP theoretically, conducts the typical survey of the EAP implementation of a domestic enterprise; establishes multivariate linear regression equation of EAP utility; sets up an allocation model of EAP cost through Analytic Hierarchy ProcessThis dissertation\'s conclusion is that EAP cost is related to the time and frequency of EAP used by employee under the fixed cost, the tendency of using EAP is related to demographic characteristics and other factors, the utility of EAP is related to the personal preference of using EAP at least, the utility of EAP is leastwise related to 7 factors, the relationship with the supervisor is the most important factor in the workplace, personal health is the largest part of EAP cost.

本文的创新成果主要是内容上的创新和方法上的创新：对EAP的内容进行了全面、系统的梳理；对EAP的成本、效用和实证研究进行了综述；对EAP的成本、效用进行了理论上的探讨；对国内企业实施EAP的情况进行了典型调查；建立了EAP效用的多元线性回归方程；用层次分析法建立了EAP的成本分摊模型。本文得出的结论是：在固定成本不变的情况下，EAP的成本与员工使用EAP的时间及次数有关系；EAP的使用倾向与人口统计学特征和其它因素有关；EAP的效用至少与个人对EAP的使用偏好有关；EAP的效用至少与7个因素相关；与上级的关系是工作场所中最重要的因素；个人的身体健康是EAP成本中花费最大的部分。

When Tullio Campagnolo was forced to withdraw from a race at the top of the Croce dAune Pass in the Dolomites because of adverse weather conditions, he conceived the idea to develop a quick release mechanism for bicycle wheels. This and many of the ideas that followed were to mark decisive stages in the development of the modern competition bicycle.

从1930年Campagnolo第一个产品专利注册，到1940年这十年是这家公司的基础起步阶段，它取得成功的秘密是在于其第一手的比赛经验，恒久不变的意志，技术上要求完美性以及宣传上独到深厚的感觉，他们宣传上把当时赫赫有名的自行车车手的名字联系到一起，做到了完美的结合。

It is well known that fingerprints of an individual are unique and are normally unchanged during the whole life.depends on this kind of unique and stability,we can get up a person together with his fingerprint, and can verify his identity by comparing his fingerprint with the fingerprint keeped in advance.this is the fingerprint-identify technique.as one of living characteristic identifies ,it has been applied in many kinds of safe system:simple lockfast system;complicated controlled gate system;fingerprint and intelligence card combination application;network safety depending on the fingerprint identifies etc.

摘要众所周知：每个人的指纹是唯一的并且终生不变的。依靠这种唯一性和稳定性，我们就可以把一个人同他的指纹对应起来，通过比较他的指纹和预先保存的指纹进行比较，就可以验证他的真实身份。这就是指纹识别技术。作为生物特征识别的一种，由于它具有其它特征识别所不可比拟的优点，使得自动指纹识别被广泛地应用于各种安全系统中：简单保险柜/箱系统；较复杂的门禁系统；指纹与智能卡结合应用；基于指纹识别系统的网络安全等。

As soonas it was restored,I said that for years and yearspast I hoped I had had as many American friendsand had received as many American visitors as al-most any Englishman living,and that my unvary-ing experience,fortified by theirs,was that it wasenough in England to be an American to be re－ceived with the readiest respect and recognitionanywhere.

我在恢复了正常的严肃性后说，多少年来我希望像任何一个活着的英国人一样，拥有那么多的美国朋友，接待那么多的美国来访者，并且希望他们的经验会加强我的一条不变的经验：一个美国人在英国到处都会充分地受到发自内心的尊重和关心。

Using Field single ignition experiments of the four unconfined volume dispersion and small dosage solid FAE and TNT bombs experiments, we got the peak overpressures of solid FAE at different distances. Compared with TNT, The overpressure of FAE is 1.14~1.6 times higher than that of the TNT. Based on the theory of the air shock wave overpressure, the FAE relativity TNT mass is evaluated. At the edge of the explosive field, the number is 3.88. Pictures of high speed photography indicate that the duration and the most effect area of the FAE and TNT. Compared with TNT, obviously the FAE has more advantages. And, based on the theory of the critical concentration of dust explosion, the radius of dust explosive zone is evaluated. The phenomenon that the overpressure decays rapidly with distance is analyzed. It is suggested that the explosive temperature should be increased as the main approach to improve the FAE explosive capability in the condition when the over pressure is invariable.

通过四组无约束固态燃料空气炸药装置与等质量的TNT在野外开放空间的一次起爆对比实验，测得了不同配方组份FAE装置在不同距离的爆炸超压分布，FAE装置峰值超压比相同距离的TNT高1.14-1.6倍；并运用空气冲击波峰值超压公式计算出了FAE的等效爆炸TNT当量随距离的变化关系，在爆炸场边缘区，FAE装置爆炸当量达到了3.88倍TNT当量；通过高速摄影的图片得到了爆炸产生火球的持续时间和最大作用范围，与等质量TNT爆炸火球相比，FAE的优势明显；运用粉尘爆炸下极限浓度估算了云雾爆轰区半径，并分析了测量到的固态FAE爆炸场的压力分布单调衰减的原因；建议在保持超压不变的情况下，把提高爆温作为提高FAE爆炸性能的主要途径。

This thesis insists that farmer household should be re-cognition in such condition, which analyzes peasants in a developing and historical process. The thesis tries to prove that peasants are at the entrance of socialized small agricultural economy stage although the scale of farmer household' s management is still too small. It also points out that peasants are engulfing into an open mobile socialized system with division of labor, which is far-off closed traditional small agricultural economy.

本文基于家庭经营体制长期不变的条件，提出&重识农户&，即将农户放在历史变迁的过程中加以考察，认为，尽管当今的农户经营规模小，但他们已越来越深地进入或者被卷入到一个开放的、流动的、分工的社会化体系中来，与传统的封闭的小农经济形态渐行渐远，进入到社会化小农的阶段。

We promise that the quality is unchanged; service is unchanged; credibility is unchanged; empressement is unchanged!

我们可以坚定承诺的是：品质不变，服务不变，诚信不变，真诚不变！

Ccile Perez, owner of La Fronde, a typical Parisian neighborhood caf said:"In the morning, street cleaners in bright green uniforms sip coffee next to well-dressed businessmen; at lunch hour, working-class types rub shoulders with those of the latest fashion at the bar, while couples of all ages rub noses over salads; during the after-work rush, there is a steady soundtrack of clinking glasses combined with conversation; the constant, no matter what time of day, is the smoke that drifts through the air in curls and clouds, seemingly unnoticed."

佩雷斯是La Fronde，一个典型的巴黎附近咖啡馆的老板，他表示：&穿着明亮的绿色制服的清道工人早晨会来喝咖啡而旁边则可能坐着衣冠楚楚的商人；在午餐时间，工薪阶层会在酒吧与身着最新时装的潮人比肩而座；与此同时各年龄层的夫妇会边吃沙拉边擦鼻子；在下班后的酒吧高峰期间，酒吧内总是说话声夹杂着杯盘的叮当声。一天中无论何时，唯一不变的是人们抽烟吐出的阵阵烟圈，形成烟雾、向空中排放着，似乎被忽视了。&

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。