无特性的

Statistical properties of this network are discussed, including typical distance from one node to another and a variety of measures for connectedness within a network, such as closeness and betweenness.

通过分析可知，家电企业竞争网是一个具有无标度特性及小世界特性的网络，呈现出节点择优连接，网络同类匹配等一系列网络现象。

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。

The basic characteristic of modern society in its floating form is its rootlessness.

现代社会作为一个漂浮的形态，其基本特性的现代性就表现为社会无根特性。

The bondless pressure contact devices are found to have comparable electrical characteristics to substrate mounted devices.however due to differences in the mechanical and thermal properties,these devices may offer exploitable advantages in some applications.

我们发现无焊压装器件和基板安装器件有相当的电气特性。然而由于机械和热特性的不同，在一些应用场合它更可能提供优势。

In order to select a kind of eminent grass which is adaptable to the northern China, the present thesis studies ten kinds of grasses from Gramineae, Bromus biebersteinii,Bromus inermis,Festuca arundinacea ,Festuca rubra,Dactylis glomerata ,Phleum pratense,Agropyron desertorum,Agropyron smithii,Elytrigia elongate and Phalaris arundinacea,and also explores the physiological aspects of their drought resistance, cold tolerance and barren resistance. The drought resistance experiment was conducted to study 10 grasses under water stress during seedling stage by simulating indoor drought environment.

为了能选适应我国北方地区的抗旱、耐寒、耐贫瘠特性的优良牧草，本研究以草地雀麦、无芒雀麦、苇状羊茅、紫羊茅、沙生冰草、蓝茎冰草、长穗偃麦草、猫尾草、鸭茅、草芦为材料，在抗旱、耐寒和耐贫瘠性特性三方面的生理方面进行了探索研究。

Taking cydid gear-pin rail chainless traction mechanism of MG375W as an example, make theoretical deduction for the profile and the kinematic characteristics of the cycloid gear , and make simulation analysis for some different engaging positions by computer.

以MG375W采煤机的摆线轮与销排无链牵引机构为例，进行了摆线轮齿廓特性及运动特性的理论推导，对不同的啮合工位进行了计算机模拟仿真分析，得出了中心距及节距发生变化引起啮合传动特性的变化规律。

Water color ink of environmental protection is a kind of product without poison,shock-gas and corrosivity.

环保型水性油墨具有无毒、无刺激性气味、无腐蚀性的优良特性，产品在使用过程中可直接用自来水或乙醇稀释，对环境和人身体都不存在危害。

They have very intensive optical nonlinear effect, high birefringence, fantastic dispersion, ceaseless single mode transmission characteristic and dreamlike performance parameters. They can be used to form lasers with higher average power or peak value power. In a word they are the instruments that can rein the photon imaginably! Various theories and numerical analyzing methods of the photonic crystal fiber laser have been listed.

研究了有望构成更高平均功率连续激光器或更高峰值功率脉冲激光器的新材料——光子晶体光纤，介绍了其拉制方法，说明光子晶体光纤具有极强的光学非线性效应、高的双折射特性、奇异的色散特性和永无截止的单模传输特性等各项新颖奇特而且优异的性能指标，一句话，就是它是最有可能拥有完美的驾驭光子的能力的器件！

Their death-black, faceless metal armor could not be penetrated by the simple stones and arrows the Inta used.

他们那些致命的黑色无特性的金属装甲是因塔人所使用的那些简单的石头和弓箭武器所无法击破的。

However, you can create mix-in classes by inheriting from "object".

然而你可以通过从object继承来创造mix-in类。object是一种新的built-in，在新系统下为所有built-in type命名的无特性的基type。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了