不可靠

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。

Above all, consider combination of 3 kinds of load and different constant load and alterable load effect to compare an effect, gave out representative ferroconcrete component is in give an environment to fall, the affirmatory principle that the reliability of different operating period analysed methodological; to put forward intended performance structure to design reliability level, namely index of reliability of component part of the construction inside intended performance cannot be under the standard; of active standard on foundation of expression of design of reliability of our country structure introduce wear to fold decrease coefficient, gave out the affirmatory method of this coefficient, assure in design phase through this coefficient and achieve target of reliability of component part of the construction inside intended performance not the standard under active standard.

首先，考虑三种荷载组合以及不同恒荷载和可变荷载效应比影响，给出了代表性钢筋混凝土构件在给定环境下、不同使用期的可靠度分析方法；提出了预期使用期结构设计可靠度水平的确定原则，即预期使用期内结构构件可靠度指标不能低于现行规范的标准；在我国结构可靠度设计表达式基础上引入耐久性折减系数，给出了该系数的确定方法，通过该系数在设计阶段保证和实现预期使用期内结构构件可靠度指标不低于现行规范的标准。

Themain characteristic is: due to use three eccentric configuration, hermetic capability reliably , which ensure disc never touch sealingseat when it start, solve the problem of hermetical seat burden unequally, prolong service life, and ensure reliable hermetic capability with advantage of high temperature resistant , wearable, antisepsis etc.

其特点为：由于采用的是三偏心结构，密闭性能可靠，确保开启时蝶板不接触密封座，消除了密封座不均匀负载，延长了使用寿命，确保可靠的密封性能，具有耐高温，耐磨损，耐腐蚀等优点。

Then, safety analysis method was constituted considered the typical damage of concrete beam bridge. 5. By amending the reduction rate of loading capacity used in Code for Maintenance of Highway Bridges and Culvers (JTG H11-2004), a new reliable index is presented in the same safety standard to reflect the relation between load and resistance. According to the basic principal of calibration method, the recommended gradation index was computed under various factors such as different load combinations, vehicle operating status and different failure modes. With these calculated numerical values, the calculated reliability indexes standard for the estimation of safety degree of in-service concrete girder bridge members was ultimately obtained.6. Based on the related standards and results on crack and displacement that cannot continue to loading at home and abroad, the evaluation grade of the concrete beam bridge is proposed by analogy.

针对材料和构件损伤对混凝土梁式桥抗力的影响，基于材料和构件层次典型损伤的修正计算公式，在结构既有以及时变抗力评估的概率模型基础上，通过误差传递公式获得抗力统计参数，对抗力进行修正，构成了考虑混凝土梁式桥典型损伤的安全性分析方法。5、依据校准法原理，将《公路桥涵养护规范》(JTG H11-2004)中不同类别承载力下降率转化为修改分项系数，分别计算了轴心受压、轴心受拉、受弯、大偏心受压、受剪构件在各种情况下的可靠指标，根据破坏类型对校准结果进行分析，提出了基于可靠度的公路混凝土梁式桥安全性评定等级。6、基于不能继续承载的裂缝和位移的相关国内外规范和研究成果分析，通过类比提出了混凝土梁式桥不能继续承载的裂缝和位移评定等级界限。

Aimed at the characteristics that design conditions of the foundation structures of offshore long-span-bridges are different from that of common bridges, the partial factors, the target reliability indices and the factors of wind load in different design fields were all analyzed. Then, three levels of target reliability indices which are 1.5, 2.0 and 2.3 respectively, and the corresponding factors of frequent value and quasi-permanent value of live loads based on JCSS model code with JC method were suggested.

针对大型跨海桥梁基础结构正常使用极限状态的设计条件不同于一般桥梁的特点，对各类不同设计领域的设计分项系数、目标可靠度指标及风荷载系数进行了分析和比较；然后以JCSS模式规范为基础，通过可靠度计算的验算点法，经过多次试算，建议了目标可靠度指标分别为1.5、2.0和2.3的三级可靠度水平及相应的可变荷载频遇值系数和准永久值系数。

The conveyed medium can't be leaked outside. Thus it will not cause the environmental pollution and human body safety dangerous while exhausting the toxin and flammable or corrosive medium. 5、No electricity. It's safe and reliable while using in the flammable and explore places. 6、It can be soaked in medium. 7、It's convenient to use and reliable to work. Only open or close the gas valve body while starting or stopping. Even if no medium operation or pausing suddenly for long time because of accident matters, the pump will not be damaged caused by this. Once over-loading, the pump will automatically stop and possesses the self-protection function. When the load recovers normally, it also can start automation. 8、Simple structure and less wearing parts. This pump is simple in structure, installation and maintenance. The medium conveyed by the pump will not touch the matched pneumatic valve and coupling lever etc. not like other kinds pumps, the performance will drop down gradually because of the damages of rotor, gear and vane etc. 9、It can transmit the adhesive liquid (the viscosity is below 10000centipoise) 10、 This pump needn't the oil lubricant. Even if idling, it has any influence to the pump. This is a characteristic of this pump.

所以抽送有毒、易挥发或腐蚀性介质时，不会造成环境污染和危害人身安全； 5、不必用电，在易燃、易爆场所使用安全可靠 6、可以浸没在介质中工作 7、使用方便、工作可靠、开停只需简单地打开和关闭气体阀门，即使由于意外情况而长时间无介质运行或突然停机，泵也不会因此而损坏，一旦超负荷，泵会自动地停机，具有自我保护性能，当负荷恢复正常后，又能自动启动运行； 8、结构简单、易损件少，该泵结构简单，安装、维修方便，泵输送的介质不会接触到配气阀，联杆等运动部件，不像其他类型的泵因转子、活塞、齿轮、叶片等部件的磨损而使性能逐步下降； 9、可输送较粘的液体（粘度在1万博以下）； 10、本泵无须用油润滑，即使空转，对泵也无任何影响，这是该泵一大特点

More than likely she's some fly-by-night gypsy, out to make a quick buck.

她更像个不可靠的吉普赛人出来骗点钱。

More than likely she's some fly-by-night gypsy, out to make a quick buck.

她更像个不可靠的吉普赛人，出来搞点儿快钱。

The algorithm is implemented by a three-stage iterative process. At the first stage, an iterative block matching algorithm is applied to generate more accurate initial disparity vectors, and at the second stage, an iterative polygon matching algorithm is employed to optimize the initial disparity vectors obtained at the first stage to minimize the error of certain triangulations. Finally at the third stage, the unreliable nodes are deleted.

该方法是一个三步迭代过程：首先利用迭代块匹配算法得到较精确的匹配结果；然后利用迭代多边形匹配算法对得到的匹配结果进行优化，使得一些三角形的预测误差最小；最后删除掉视差不可靠的节点。

If you want to know how long the reign of George V lasted, you will probably need to look it up, and you're always in jeopardy of your sources being unreliable.

如果你想知道乔治五世在位的时间有多长，你可能需要去查历史文献，而你总得担心你的文献来源有可能是不可靠的。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。