查询词典 root ball

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。

Firstly, the developing principles of the cylindrical internal helical gear are proposed through analyzing the movement and geometry requirements, which provides continuous contact between the mating gear surfaces. The tooth surface of the internal helical gear in the new gearing can be imagined as being generated by the normal section of the conjugated surface of the ball-tooth, moving along the radial projection of helix line of the tooth-root circle. Also, the proposed surface can be approximate tangent to the conjugated surface of the ball-tooth along a spacial curve.

首先，通过分析保证行星轮作螺环运动时与内斜齿轮实现连续啮合传动的运动和几何条件，提出了圆柱内斜齿轮齿面的两种形成原理：即由球齿运动包络曲面的法截面沿其齿根圆螺旋线在径向的投影进行拓展所形成的内齿面，以及与球齿运动包络曲面呈近似相切接触的等螺距齿面构成的内齿面。

Bud ball was a high nutrition vegetable after blanching culture; and the root was a high nutrition feedstuff.

软化后的芽球是一种营养价值较高的蔬菜，软化后的根株是一种营养价值较高的饲料。

The micronization treatment of the peels of root and tuber crops was performanced by using ball mill in this experiment.

本实验利用甘薯、芋头及山药的皮进行微细化球磨处理，探讨微细化果皮之功能特性。

Usage:1 operation puts on glove both hands right away as simplely as hairdressing the ordinary time that hair wetting (is sent out despite grey hair dirty hair greasy dirt).2 uses towel water to be wiped clean a product has been started according to 1:1 proportion pressure add mixing slightly long hair grey hair is more multipurpose than the bob may be some short (double the first time usageretinue with hairdressing the ordinary time).3 changes over and over again for on readjusting oneself to a certain extent in hair crumple in a ball wipe must let hairdressing show the root segment touching to hair per crumplein a ball wipe.4 fades for reaching a block of wood must need to continue using 3 time or the above hairdressing shows redresses right away therefore hair has been dirty because the product belongs to one kind of nutrition vegetablerubs black hair in you wipe the now and then slowly thorough hair follicle you will own headlong jet-black elegance gradually get rich above persisting in using product 6 months if grey hair person not being disconnected.

使用方法：1、操作就像平时洗发一样简单，戴上手套双手把头发润湿（不管白发、脏发、油污发）。2、用毛巾把水擦净，把本品按1：1比例倒入手上稍加搅拌，长发白发要多用，短发可少些，（初次使用以平时洗发的两倍左右）。3、放在头发上反复揉搓，必须让洗发露沾到每根头发的根部，揉搓可快可慢，累了可稍加休息，总之不停的在头发上前后左右揉搓，特别是根部，坚持7-10分钟的揉搓可冲洗，见到的是一头乌黑亮丽的黑发。4、本品为营养性促黑养发产品，必须要连续使用3次或以上。

The treatment of high-hydroscopicity resin seed-coatingmaterial can fornl a water-stored ball of about 1. 8 cm × 1. 5 cm × 1. 2 cm around seed and root, the ball has the abilities of absorbing, keeping and providing water. As the ball containing pesticide, germicide and plant regulatorand releasing slowly, it may afford a suitable surroundings for germination an...

高吸水种衣剂包衣处理在种子周围及秧苗根部形成了18cm×1.5cm×1.2cm左右的&蓄水球囊&，不仅提高了种子出苗率、成秧率，有效地防止了多种病虫害及死苗的发生，壮大根群，提高了秧苗素质；而且实现了旱育秧苗根部带土抛植，提高了立亩速度和抗植伤能力，增加了旱育抛栽稻的产量。

The changes of total branch length, expending rate of root and ball root rate decline with the increase of N clement, which shows that after using N ,the root tuber of Juema lies not a commercial value.

蕨麻总分枝长、根系膨大率、球根率则随N素水平的增加而直线下降，表明施用N素后蕨麻块根不具有商品价值。

Cuju, or kick ball, took root during the Han dynasty (206 BC to 220 AD), perhaps to help the imperial cavalry play off the numbness of long rides. The stitched leather ball was filled with fur or feathers, and goals could be round holes cut into silk sheets.

也许是为了帮帝国骑兵们打发行军途中的无聊时光，&蹴鞠&在汉代（公元前206至公元220年）就出现了，那时用皮缝制的球里面填充的是羽绒，在丝绸床单的中间挖个圆孔就是球门了。

Fancy gold-plated dangling earrings with facetted White Opal crystals.

花式镀金悬垂耳环与facetted白欧泊水晶。

This essay chooses the study aim from biology teachers in middle school in Shi Jiazhuang which tells us that most of the middle school biology teachers in Shi Jiazhuang have the"burnout", lower successfulness, individualize.

本文选取石家庄市初中生物教师作为研究对象，运用问卷调查的方法对石家庄市初中生物教师职业倦怠的现状进行调查，调查结果发现，石家庄市初中生物教师这一群体普遍存在职业倦怠，情感枯竭程度偏高，成就感偏低，去个性化程度最为严重。