变化性的
- 与 变化性的 相关的网络例句 [注:此内容来源于网络,仅供参考]
-
However, this conversion is presented just for completeness, and therefore, is not encouraged.
例如,这是非侵入性,它并没有什么要求变化到现有网络的基础设施。
-
Objective : To observe of expression of NT-3 of the conus medullaris neuron with cauda equina compressed injury .
目的:探讨马尾神经压迫性损伤后不同时间骶髓神经元中神经营养因子-3的表达变化。
-
Objective: To study the clinical significance of serum neuron specific enolase in children with febrile convulsion.
目的:探讨热性惊厥患儿血清神经元特异性烯醇酶变化的临床意义。
-
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 study indicates that the frost heaving character of the meal sand is decimus of silt clays. And its frost heaving quotiety is seldom influenced by the different freezing end temperature and water content. Thus the surroundings influence is in the small area when the artificial freezing method is used in sand and no-stickiness soil.
研究结果表明粉砂冻胀率是淤泥质粘土冻胀率的十分之一,冷端温度、含水量两个因素变化对其冻胀率几乎不产生影响,因此在砂性等无粘性土中应用冻结法对周围环境危害较小。
-
Chapter two discusses basic characteristics and types of changes of complex declarative knowledge.
第二章着重论述复杂陈述性知识的特征和变化类型。
-
The fundamental histopathological changes of intracranial aneurysms are inury, denaturalization and repair.
颅内囊性动脉瘤所表现的基本组织病理变化为损伤、变性和修复。
-
The appearances of irregular secondary dentine is not a pathological change but a physiological feature.
不规则性继发性牙本质的出现属于生理现象而并非病理变化。
-
Especially, the pattern of the construct both aggregate and desegregate in design was to realize different light intensity illumination on same biology sample at the same time.
结果发现,培养人皮肤成纤维细胞的增殖在接受89mJ/cmZ、21 4mJ/cmZ照射剂量后无变化,而在接受428mJ/emZ照射后,与对照组相比有显著性差异。
-
AIM To investigate the relationship between plasmic diamine oxidase and gut injury in acute necrotizing pancreatitis.
目的 探讨急性坏死性胰腺炎时血浆二胺氧化酶水平变化及其与肠道损伤的关系。
- 推荐网络例句
-
Finally, according to market conditions and market products this article paper analyzes the trends in the development of camera technology, and designs a color night vision camera.
最后根据市场情况和市面上产品的情况分析了摄像机技术的发展趋势,并设计了一款彩色夜视摄像机。
-
Only person height weeds and the fierce looks stone idles were there.
只有半人深的荒草和龇牙咧嘴的神像。
-
This dramatic range, steeper than the Himalayas, is the upturned rim of the eastern edge of Tibet, a plateau that has risen to 5 km in response to the slow but un stoppable collision of India with Asia that began about 55 million years ago and which continues unabated today.
这一引人注目的地域范围,比喜马拉雅山更加陡峭,是处于西藏东部边缘的朝上翻的边框地带。响应启始于约5500万年前的、缓慢的但却不可阻挡的印度与亚洲地壳板块碰撞,高原已上升至五千米,这种碰撞持续至今,毫无衰退。