控制光和信号光频差对太赫兹光非对称解复用器性能的影响

讨论了半导体光放大器中的带间效应，及载流子热效应、谱烧孔效应、双光子吸收以及超快非线性折射等带内效应对半导体光放大器的动态特性的影响，讨论了两种情况：1)保持控制光波长不变而改变信号光频率，2)保持控制光和信号光频率相同而同时改变它们的频率下半导体光放大器的增益、相位动态特性以及太赫兹光非对称解复用器的开关窗口特性。数值结果表明，为了得到较为平坦而窄的开关窗口，控制光波长应与信号光波长相同，且其与半导体光放大器增益谱中心波长的差值应该大一些。     

400GeV/c pp碰撞赝快度空间带电粒子数密度的研究

利用CERNNA27合作组提供的LEBC泡室照片,测量了400GeV/cpp碰撞产生的带电粒子多重数为4—24的赝快度分布.观察到在选择的赝快度窗口(Δη=0.5和0.1)内平均最大带电粒子数密度随带电粒子多重数线性增加的规律.最大带电粒子数密度的几率分布在n大时有加宽和变平坦的趋势.没有观察到最大粒子数密度反常高的事例.     

染料敏化TiO2/WO3薄膜电池的光电变色

用光电化学方法研究了染料Ru(П) (4, 4′di COOEt 2, 2′bpy)2 (2, 2′bpy 4, 4′di CONH L tyrosineethylester) (PF6)2 (简写为Ru4)敏化TiO2 纳米结构电极的光电转换过程,同时,在导电玻璃上电沉积得到WO3 薄膜.结果表明,染料敏化的TiO2 多孔膜具有光电转换性能, WO3 薄膜具有良好的电致变色效应,将前者与电沉积得到的WO3 薄膜组成电池,在白光照射下可产生显著的颜色变化,有望用于自供电源的电色灵巧窗(Self poweredsmartwindow).     

Sliding acceleration of water droplets on a surface coated with fluoroalkylsilane and octadecyltrimethoxysilane

Both fluoroalkylsilane (FAS) and octadecyltrimethoxysilane (ODS) were coated on oxidized silicon wafers using soaking and CVD method. Smooth coatings with Ra values of less than 1 nm were attained. The slope of the sliding acceleration against the inverse of the droplet mass showed an inflection point. That point shifted to the direction of smaller droplets with decreasing FAS ratio to ODS. The water droplets’ length was increased when the sliding velocity was increased. Fluoroalkylsilane addition to ODS increases the interaction between water and the hydrophobic surface. Results showed that the sliding acceleration of a water droplet depends strongly on the surface ratio of these silanes.     

BANDWIDTH SELECTION IN NONPARAMETRIC SPECTRAL DENSITY ESTIMATION OF THE STATIONARY GAUSSIAN PROCESS

ＢＡＮＤＷＩＤＴＨＳＥＬＥＣＴＩＯＮＩＮＮＯＮＰＡＲＡＭＥＴＲＩＣＳＰＥＣＴＲＡＬＤＥＮＳＩＴＹＥＳＴＩＭＡＴＩＯＮＯＦＴＨＥＳＴＡＴＩＯＮＡＲＹＧＡＵＳＳＩＡＮＰＲＯＣＥＳＳ￥ＹＵＤＡＮ（于丹）（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ，...     

Absorption of millimeter to submillimeter waves by atmospheric water molecules

Using the values of the rotational molecular parameters (including cencrifugal distortion terms) of the H₂ ¹⁶O molecule, which can explain 12 observed transitions below 800 GHz, all rotational energy levels with normalized Boltzmann factors larger than 5×10^–8 at 300°K are calculated. Probabilities of all possible electric dipole transitions among these states, 2277 lines, are calculated using the eigenfunctions thus obtained, and the permanent electric dipole moment of 1.8546 Debye. Assuming the single and full Lorentzian line forms, we calculated the absorption coefficient for millimeter to submillimeter region. Our result, using the single term Lorentzian line form, agrees quite well with experiment for 1 Torr of water vapor in 760 Torr air at 300°K.     

光学窗口外形对气动光学效应的影响

 流场求解采用3维雷诺平均N-S方程,分别利用ROE格式和二阶中心格式对对流通量和粘性通量进行离散处理;用高斯-赛德尔隐式格式对方程进行时间推进求解,采用k-ε两方程模型用于湍流的数值模拟。采用几何光学结合物理光学方法分析平均流动和湍流对光场的影响。计算结果表明:由于窗口外形曲面的曲率不同,两种窗口外部流场存在较大区别,气流速度、密度的分布情况各不相同。曲率较大的窗口外形对气流的压缩程度较大,导致气流绕过窗口顶端中心区域时流速快,密度梯度大,因而窗口空气阻力较大,光束在该窗口流场中传输受气流影响的影响也较大。     

超高声速飞行器光学窗口气动光学效应分析

超高声速飞行器在大气中飞行时,由于气动热和气动力的作用,光学窗口会产生严重的气动光学效应,使目标图像发生像偏移、抖动、模糊和能量衰减。利用有限元分析方法对光学窗口的热光效应、弹光效应和窗口热变形进行研究,计算了由热光学效应、光学窗口热变形引起的点扩散函数峰值大小及峰值位置(像偏移)随时间的变化趋势。根据对温度场的分布分析,计算了温度梯度对透过率的影响以及透过率与窗口热辐射随时间变化的趋势,可为光学窗口的设计、材料的选择及后期的图像处理提供依据。     

Insertion loss of sound waves through composite acoustic window materials

This study evaluated the insertion loss of sound waves through composite acoustic window materials for sonar dome applications, and examined the influence of dome shape on the sonar performance. The insertion loss of sound waves through acoustic window materials was experimentally measured as a function of frequency at normal incidence. The insertion loss was also theoretically estimated with three- and four-medium layer models. The theoretical estimation of insertion loss showed good agreement with the experimental measurements. The insertion loss was also measured as a function of angle of incidence. The characteristics of longitudinal and converted shear waves were observed at various angles of incidence. This study will be useful to select acoustic window materials with the appropriate acoustic characteristics for practical sonar dome applications.