向中心

Because of inappropriate operation between oncoming straight and left-turn vehicles of signalized intersections of urban areas in Taiwan the department of traffic ever offered corrigible opinions involve in right of way, center of intersections adjudging hard and indirectly encouraged to accelerate left-turn vehicles. But all still lack quantification analysis. Therefore, this problem is worth studying.This study will aim at safe passage of oncoming straight and left-turn vehicles for at-grade signalized intersections. So, this study will be based on row's theory, theory of traffic conflicts, and take many factors into consideration, such as the width of the intersections, types of the intersections, center of the intersections, the size of the vehicles, the location of the vehicles, the radius of turn, paths of operation, the speed of the vehicles, the types of collisions, the angle of road, and also deduce formulas of coordinate of paths. The main method used in this research is the simulation of different situations. By the method, the analytic model of safe passage of oncoming straight and left-turn vehicles for at-grade signalized intersections will be established, and this study will also subsume critical speed of conflict and expected number of times of safe passage. Finally involved rules of safe passage will be proffered.

鉴於台湾都市地区路口对向直行左转车辆常遭受对向车辆不当驾驶行为干扰，因而道路交通主管机关曾针对路口对向直行左转相关道路交通法规可能产生之对向直行左转路权判断不易、路口中心处不易区分、间接鼓励路口转弯车加速左转等问题提出检讨之修正意见，唯整体考量仍缺少〝量化〞分析，系一值得研究之课题，因此，本研究将针对号志化平面路口对向直行左转车辆安全通行问题於法规层面上之特殊性，以交通冲突理论、路权理论为基础，并考量路口宽度、路口型式、路口中心处、车辆尺寸、转弯半径、运行轨迹、行驶速率、行车位置、最终碰撞型态、道路交角等因素，先行推导车辆行驶轨迹座标公式，再利用情境模拟分析法，进行号志化平面路口对向直行左转车辆安全通行分析，分析过程中则纳入冲突临界速率与安全通行期望次数理念，并根据路口对向左转车辆安全通行轨迹、速率集中分布范围之分析结果及相关理论，研拟号志化路口对向左转车辆安全通行轨迹、速率，及对向直行左转车辆路权判断原则，以供驾驶者路口直行左转安全通行之参考。

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。

Images from NASA's Hubble Space Telescope show that star formation in the galaxy began fizzling out in its outskirts about 500 million years ago as some of the gas was stripped away and the rest collapsed toward the center.

根据哈勃太空望远镜图像，随着气体耗尽，星系中外缘的恒星诞生在5亿年前就逐渐熄灭了，并且迅速向中心传导。

The proliferative cells remarkably trended to the center.

增生的细胞由周围向中心推进明显。

Physiology moving of a body part toward the central axis of the body.

身体其他部分向中心运动。

The real tangential velocity fluctuation indicated that there existed an instability of swirling flow in the cyclone.This instability resulted in the rotation center of the swirling flow deviating from the geometric center of the cyclone,which produced the quasi-periodic oscillation of swirling flow and gave the real tangential velocity fluctuation.

瞬时切向速度的变化反映了旋风分离器内旋转流的不稳定性，这种不稳定性导致了旋风分离器内旋转流的旋转中心与几何中心不重合，旋转中心围绕着几何中心摆动，由此造成了瞬时切向速度随时间的类周期的波动变化。

As for epidotesfrom blueschist, X_=0.22--0.36, and their composition varies remarkablyeven.in the same sample. In general, fine--grained epidotes contain relativelylow ps while things are just the opposite for coarse--grained ones whichcommonly exhibit zonal structure characterized by the gradual decrease of pstowards the core, suggesting that the bluescbist might have experienced apressuree--decline metamorphic process.

s=0.22—0.36，其成分在同一样品中也有很大变化，一般细粒者ps分子少，而粗粒者ps分子多，且常发育环带结构，向中心ps分子减少，说明蓝片岩可能经历了一个以降压为特征的变质过程。

To design a good lanthanide luminescent sensor, a unique combination of features must be realized: high selectivity and recognition to lanthanide ions; presence of multiple absorbing groups suitable for energy-transfer ; high thermodynamic stability and kinetic internees.

一个优良的发光器件必须具备以下几个条件：配体对金属离子有较高的选择识别性能；配体含有共轭发色团有利于能量从配体向中心离子转移；配合物具有相对较高的动力学和热力学稳定性。

Analyses of the EAWJ seasonal variation and the atmospheric meridional temperature gradient in the mid-upper troposphere indicate that the EAWJ center always corresponds to the largest meridional temperature gradient in the mid-upper troposphere, suggesting that the seasonal variation of EAWJ is a response to the meridional temperature difference.

分析急流与对流层中上层经向温度梯度的季节变化发现，急流出现的位置总是对应着经向温度梯度较大区域，急流中心有随气温南北差异大值中心移动的趋势，急流中心与最大温差中心相对应，表明急流中心的位置变化是对气温南北差异季节变化的响应。

In accordance with Paragraph 3 of the Rules, the Complainant shall be required to send or transmit its complaint under cover of the Complaint Transmittal Coversheet set out in Annex A hereto and posted on the Center's web site.

通知注册管理机构投诉人在向中心提交投诉书的同时，应将投诉书副本提交至有关注册管理机构。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。