无变化的

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。

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In about a century' s time, their livelihood of swidden agriculture has been changing greatly along with the natural and social environment change. Before 1950s, as a minor group frequently move in the subtropical mountainous area characterized by scarce arable land, high forest coverage rate and sparse population, Kemu people has long been engaged in swidden agriculture which was simple, called for no sophisticated production tools and was suitable for frequent movement. At that time, they adapted to the environment change mainly by moving frequently from one place to another, and their livelihood was featured by complete dependence on environment, frequent movement and swiddening without continuous cultivation. From 1950s to early 1970s, their way of adaptation changed into migration within defined territory and shortterm fallow featured by complete dependence on environment, migration within limited area and short fallow. In early 1970s, they leaned from outside to cultivate irrigated fields and plant cash forest and their livelihood was featured by complete dependence on environment and agro-forestry.

近一个世纪以来，随着其所处自然环境和社会环境的变迁，其刀耕火种的生计方式在不断地变化：20世纪50年代以前，作为频繁迁徙于山多地少、森林覆盖率高、人烟稀少的热带、亚热带山区的弱小族群，以开发容易，便于流动作业不需要复杂生产设施的刀耕火种为其传统的生计方式，主要以迁徙的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为完全依赖型、随意迁徙型、无轮作型；20世纪50年代至70年代，其主要以固定区域内迁徙和短期轮作的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为完全依赖型、在固定区域迁徙型、短期轮作型刀耕火种；20世纪70年代初，其主要以外文化——开拓水田及人工造林的方式对环境变迁进行调适，其刀耕火种生计方式的特征表现为部分依赖型、粮林轮作型刀耕火种；20世纪80年代以后，其主要以发展橡胶种植业对环境变迁进行调适，其刀耕火种生计方式的特征表现为暂时依赖型刀耕火种。

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。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐