非圆化磨耗激励下高速列车转向架区域噪声边频带产生机理及影响

该文通过对车辆噪声和车轮非圆化磨耗开展跟踪测试和分析,发现存在车轮非圆化磨耗的列车在运行过程中,其转向架区域噪声窄带频谱上会出现了以非圆化磨耗激励频率为中心,以过轨枕频率为间隔等间距分布的噪声峰值(即噪声边频带).这使得车轮非圆化磨耗不仅会影响其激励频率处的列车轨道结构的振动和噪声,还会对其他频段的噪声产生重要影响.为...     

Carrier shock and frequency conversion of a few—cycle pulse laser propagating in a non—resonant two—level atom medium

We have studied the spectral behaviour of few-cycle soliton pulses in a non-resonant two-level atom medium by solving the full Maxwell－Bloch equations. It is demonstrated further that the carrier effects play an important role in the propagation of the few-cycle pulse laser. When the frequency detuning is not very large, both the population distribution and the refractive index of the medium follow the oscillatory carrier field instantaneously; in this case, carrier-wave compression or carrier shock occurs, and a supercontinuum broader than that in the resonant medium may be generated. When the frequency detuning is large, the carrier shock is weak and the spectrum is not continuous, only showing an odd harmonic radiation.     

水环境中红霉素和罗红霉素抗生素光降解的研究

采用固相萃取分离富集,LC—MS-MS为检测平台,研究了水环境中低浓度（10mg／L）红霉素和罗红霉素的光降解效率及其影响因素。结果表明,在接近中性（pH=7．5）的水溶液中,经过1h的光照,两种抗生素的光降解率在30％以下;而在有2000mg／LTiO2催化剂存在时,光照15min,二者的降解率即可分别达95．5％和97．2%,此时溶液的pH值对光催化降解的影响不大。实验也表明,光直接降解反应和光催化降解反应均符合一级反应动力学。     

Phase Dependence of Few—Cycle Pulsed Laser Propagation in a Two—Level Atom Medium

The phase-dependent feature of few-cycle pulsed laser propagation in a resonant two-level atom medium in demonstrated by solving the full Maxwell-Bloch equations.Even in the perturbative region,the propagating carrier field and the corresponding spectra of the few-cycle pulsed laser are sensitive to the initial phase due to self-phase modulation.For the larger pulse area,the fact that the carrier-wave reshaping comes from the carrierwave Rabi flopping is also responsible for this sensitivity,and the phase-dependent feature is more evident.     

基于图像处理的玻璃瓶口裂纹检测系统设计与实现

为了快速、准确地对玻璃瓶口裂纹进行无接触检测,基于图像处理技术设计与开发了一个玻璃瓶口裂纹检测系统。首先对获取的玻璃瓶口图像进行降噪与分割处理,并利用重心法获取玻璃瓶口圆心的粗定位,然后利用边界跟踪算法对玻璃瓶口进行边界跟踪,并通过 最小二乘拟合获取玻璃瓶口圆心的精确位置,最后利用深度优先遍历算法对裂纹点集进行聚群,从而实现对玻璃瓶口裂纹的检测。实验结果表明,该系统操作简单、效率高、抗干扰能力强,能满足实际使用的要求。     

光电导天线产生太赫兹波的研究

研究了光电导天线产生太赫兹波的辐射特性,采用时域有限差分方法(FDTD)来模拟计算光电导偶极天线的辐射特性,并在计算机上以伪彩色图进行了图形显示。采用电偶极子天线模型,以0.1THz电磁波为例计算了天线辐射的特性参数,得到天线的辐射电阻为790Ω,方向性系数为1.5。结果表明,光电导天线可以采用偶极天线的理论进行计算,可以通过提高电长度来增大辐射电阻,从而提高太赫兹的辐射功率。     

SPECTRUM OF A FEW-CYCLE LASER PULSE PROPAGATING IN A TWO-LEVEL ATOM MEDIUM

The spectrum evolution of a few-cycle optical pulse in a resonant two-level atom medium is studied theoretically by using the full Maxwell--Bloch equations. On the propagating pulse, significantly much faster oscillation components separated with the main pulse appear due to strong self-phase modulation and pulse reshaping. In this case, ideal self-induced transparency cannot occur for a 2π pulse. The spectrum of the 4π pulse shows an evident oscillatory feature because of the continuum interference of the separate pulses. For larger pulse areas, continuum generation from near ultraviolet to infrared occurs.     

客户关系管理中的运筹学方法

本对近年来兴起并迅速发展的客户关系管理（CRM）与客户服务中心（Call Center）的理念,价值与方法,以及运筹学在此领域中的应用作了综述。     

建立模型找关系 抽丝剥茧现本质——“生活中的不等式”教学实录及其思考

“生活中的不等式”是以“课标(2011年版)”为依据修订的苏科版《义务教育教科书·数学》七年级(下册)11.1的内容. 一、基于课程标准的教学理解 现实世界的数量关系中,不等是普遍的、绝对的,而量的相等是局部的、相对的.等式反映了现实世界中量的相等关系,而不等式则是表示现实世界中量的不等关系的重要数学工具.在解决实际问题时,对于等量关系,可以利用等式(包括方程和方程组)来刻画;对于不等量之间的关系,我们则用不等式(包括不等式组)来刻画.研究不等式可以更好地认识和把握事物之间的运动变化及其相应的规律.在研究许多问题时,人们经常要分析其中的不等关系,列出相应的不等式或不等式组,并利用不等式求出某些数量的取值范围.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。