查询词典 decrease progressively

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。

In nearer ten years, assart grassland is very serious in the northern grassland, and show "two raise and three decrease","two raise" are farmland raise and garden raise,"three decrease" are grass decrease, forest area decrease and pasture area decrease.

近十余年来，我国北方草原地区开垦草地现象十公严重，出现了"两增三减"的现象，"两增"是耕地面积大幅度增加，园地面积大幅度增加；"三减"是牧、草地面积减少，林地面积减少。

the 160 women judoists are tested for mental fatigue and personality tests, and the paper tries to reveal their situation of mental fatigue, personality characteristics, and the relationship between them.it is analyzed that chinese elite judoists have no severe mental fatigue; judoists' negative evaluation on emotional/physical exhaustion and sport increase significantly one week before competition than two months; among personality factors, excitability predicts the decrease of achievement and emotional/physical exhaustion reliably on negative; the stability predicts sport on negative; tension predicts emotional/physical exhaustion on positive; adaption and anxiety in dimension personality predicts in positive both in the decrease of achievement and emotional/physical exhaustion and internal extraversion does them in negative; health personality in applied dimension personality predicts in negative in the decrease of achievement, emotional/physical exhaustion and negative evaluation of sport when mental fatigue, stability and sensitivity predicts the decrease of achievement in negative; only internal extraversion in dimension personality predicts the decrease of achievement and emotional/physical exhaustion in positive.

摘 要：以160名女子柔道运动员为被试，进行运动员心理疲劳以及人格测试，并尝试揭示女子柔道运动员的心理疲劳状况、人格特征以及二者之间的关系。分析得出：我国优秀柔道运动员心理疲劳程度并不严重；运动员在临赛前一个星期较赛前二个月情绪/体力耗竭以及运动的负评价显著提高；人格因素中的兴奋性对成就感的降低以及情绪/体力耗竭两维度均有可靠的负向预测作用；稳定性对运动的负评价维度具有可靠的负向预测作用；紧张性对情绪/体力耗竭有可靠正向预测作用；次元人格中适应与焦虑对成就感的降低以及情绪/体力耗竭均有可靠正向预测作用，内外向性对成就感的降低、情绪/体力耗竭以及运动负评价都有可靠负向预测作用。应用性次元人格中健康者的人格对运动员心理疲劳的对成就感的降低、情绪/体力耗竭以及运动负评价均有可靠的负向预测作用；稳定性、敏感性对临赛前成就感的降低维度的变化有可靠的负向预测作用；次元人格中只有内外向性对临赛前成就感的降低以及情绪/体力耗竭维度的变化有可靠的正向预测作用。

Biomass in the rain forest was far more than that in the plantation of 12 years,especially for the shrub layer.But the biomass of litterfall collected in the plantation was greater than that of the rain forest for the reason that Betula alnoidis defoliated in dry seasons.9 Four years observation found that soil bulk density tended to increase first, then decrease after planting trees;total soil porosity and non-capillary porosity tended to decrease and after few years they recovered to different degrees;the soil cation exchange capacity for all forest types increased;in the soil of 0-30cm depth,soil salt saturation tended to decrease;nutrient content in the soil of 0-60cm depth in the young stand tended to decline;soil effective P,effective K and N contents all tended to decrease.

山地雨林的总生物量远远大于10年生的西南桦人工林，其中灌木层的相对差别尤其巨大。94次的观测发现，人工林栽植后，土壤容重一般呈现一个先上升后下降的特点；而土壤非毛管孔隙度、土壤总孔隙度大多呈下降趋势，几年后有不同程度的恢复。

The results show that the coefficient of friction decrease progressively with decrease of the elastic modulus.

这些分析结果与经验数据和试验结果非常吻合。

Some evidence indicates that the combination of extrinsic, intrinsic and genetic factors all play a role to cause the disc degeneration, with a progressive decrease in proteoglycan content leading to dehydration of the nucleus pulposus, and Type Ⅰ collagen begins to appear in the matrix, the ratio between Type Ⅰ and Type Ⅱ increases. All these cause the swelling pressure, disc height and the disc load bearing ability decrease. The disc progressively herniate and cause radiculopathy and myelopathy.

内因、外因及遗传方面的诸多因素导致椎间盘逐步退变后，其实质就是基质中蛋白多糖的减少，含水量降低，Ⅰ型胶原出现在基质中，Ⅰ、Ⅱ型胶原的比例明显上升，髓核呈纤维样改变，导致椎间盘的膨胀压降低，承重能力下降，椎间高度降低，椎间盘承受的重力不能平均地向各方向传递，致使纤维环疲劳、破裂、髓核突出，造成脊髓或马尾神经受压，引起严重后果。

With the developing gradually of science and technology, any trade needs changing and mechanizing from former melting by hand progressively , realize intellectuality progressively again while mechanizing ; From former ones that took people as the core to today as the main fact with the machine.

随着科技的逐步发展，任何行业都需要从以前的手工化逐步转变成机械化，而在机械化的同时又要逐步实现智能化；从以前的以人为主到今天的以机器为主。

Nowadays,the economy of our country is in the fast traffic lane,the economic system of the market is perfecting progressively,the market unlocks progressively,the market-based degree improves day by day.

当前，我国正处在经济高速发展的快车道，市场经济体系逐步成熟和完善起来，市场逐步放开，市场化程度日益提高。

The marginal division was a flat fan-shaped structure with a volume of (0.48±0.02) mm3, a maximum rostral-caudate axis of 1.6 mm, a maximum dorsal-ventral axis of 2.158 mm, and a widest axis (the diameter at lateral-medial coronal brain section) of 0.17 mm. The marginal division also moved progressively externally from the rostral section to the caudate section, but its scope was larger than that of others. The whole marginal division changed evenly from the rostral section to the caudate one. Its flat structure widened progressively and its dorsal-ventral diameter narrowed gradually and became plate-shaped.

边缘区呈现一个片状扇形结构，体积为(0.48±0.02) mm3，最大嘴尾径为1.6 mm，最大背腹径为2.158 mm，最大内外径为0.17 mm；同尾壳核和苍白球一样从嘴侧到尾侧随着脑平面的增宽边缘区亦逐渐向外侧移位，其移位的幅度亦明显大于脑平面增宽的幅度；整个边缘区从嘴侧到尾侧呈均匀变化，其片状逐渐变宽，长度逐渐变小，从而形成一个盘状结构。

In contrast, the largest decrease or non-ferrous metals and real estate these two plates, many of which the first three quarters of the stock fell more than 70 percent, such as van den Bergh, a decrease of 81.72 percent stake, China Sports Industry decrease of 83.54 percent, or more than 80 % of A shares have 15 cities, which hit two folding stocks and shares last year, up 10 times in stark contrast.

相反，跌幅最大或有色金属和房地产这两个板块，其中许多是前三个季度的股票跌幅超过百分之七十，如布宏达，有百分之81.72的股份减少，中国体育产业的百分之83.54，跌幅超过80％的A股跌幅有15个城市，击中了两款折叠股票，比上年增长形成鲜明对比的10倍。

Metrorrhagia is also gynaecological problems of common diseases.

崩漏是妇科常见病也是疑难症。

WordFTP gives you the convenience and timesaving you need.

wordftp让您的方便和省时您所需要的。