一种新的CO_2高温辐射特性窄谱带模型参数计算方法

本文以美国空军地球物理实验室最新的高分辨率高温燃气光谱数据库ＨＩＴＥＭＰ（序列号：３１５３）为基础,在３００～ ３０００ Ｋ的温度范围内,计算了二氧化碳的谱带模型参数 κ,β,得到了比 １９７３年 ＮＡＳＡ发布的数据更新、更详细的数据。同时以本文的模型参数为基础,采用统计谱带模型计算了各个谱带各种光学路径下的发射率、穿透率,其结果与实验、逐线计算值（Ｌｉｎｅ－ｂｙ－Ｌｉｎｅ）符合很好。     

一种气体吸收的逐线计算模型及其实验验证

建立一种高分辨率的气体吸收光谱的逐线计算模型,分子谱线参数数据库采用了最新的低温库HITRAN2008和高温库HITEMP2010,能根据温度条件自动选择合适的谱带参数库,并可同时满足高温和常温气体辐射计算。计算波数采用等间隔取样,取样间隔大小以能分辨出典型分子谱线为条件确定。线翼截断采取等波数截断,总内配分函数由Gamache拟合三次多项式计算。谱线线型根据气体温度和压力来选择,最后,利用该模型计算了压力为1atm,不同温度、浓度和路径长度下CO2在4.3μm和2.7μm的透射率。考虑FTIR仪器增宽,将逐线计算结果降为窄带透射率,与中分辨率的试验结果对比均吻合,并能在较宽的温度范围内保证精度。     

氢化物AlH2自由基分子光谱辐射特征的研究

利用前一篇论文计算所得的振动频率、转动常数和配分函数,再将常温下的无转动跃迁矩平方近似为一常数并应用于高温,进一步编制程序,计算了氢化物AlH2分子001-000跃迁带不同温度段的辐射强度和吸收系数等谱带辐射特征.论文中计算的配分函数值与高斯计算及拟合值,不管是在常温还是高温下,都吻合较好,这说明构建的模型是可靠的,可以用来进一步计算谱带强度和吸收系数;从获得不同温度段的模拟光谱辐射特征图也可以看出,本文得到的谱带特征与文献一致.这对进一步研究自由基分子高温光谱的实验和理论都具有一定的参考作用.     

高温窑炉气体红外辐射被动遥测EI北大核心CSCD

基于傅里叶变换红外光谱技术对高温窑炉内气体红外辐射信号进行了遥测研究。根据工业现场条件,利用大气辐射原理建立被动辐射模型,计算了炉膛内高温气体透射率。针对湍流噪声对信噪比的影响,研究了红外干涉信号光谱转换的数据处理方法,以零光程差为基准对齐干涉信号,以实现多次扫描干涉信号的平均,减小了噪声和计算量,并提高了光谱数据率。利用HITRAN数据库和高温参考谱模型法,对谱线线强、线宽修正合成的校准光谱与透射谱进行非线性最小二乘拟合,反演了炉膛内不同吸收波段的高温气体浓度。结果表明该技术在窑炉内及其他工业燃烧过程中对高温气体的在线检测是可行、可靠的。     

高温窑炉气体红外辐射被动遥测

基于傅里叶变换红外光谱技术对高温窑炉内气体红外辐射信号进行了遥测研究。根据工业现场条件,利用大气辐射原理建立被动辐射模型,计算了炉膛内高温气体透射率。针对湍流噪声对信噪比的影响,研究了红外干涉信号光谱转换的数据处理方法,以零光程差为基准对齐干涉信号,以实现多次扫描干涉信号的平均,减小了噪声和计算量,并提高了光谱数据率。利用HITRAN数据库和高温参考谱模型法,对谱线线强、线宽修正合成的校准光谱与透射谱进行非线性最小二乘拟合,反演了炉膛内不同吸收波段的高温气体浓度。结果表明该技术在窑炉内及其他工业燃烧过程中对高温气体的在线检测是可行、可靠的。     

C_2O分子2.7μ带谱带模型参数和光谱发射率的计算

本文在简化考虑Fermi共振的基础上。研究了CO_2分子2.7μ组合带谱带模型参数的计算方法,给出了平均吸收系数和谱线密度间隔的系统的数据。在计算中,对低温和高温两种情况分别采用不同的计算方法,为了检验数据的可靠性,使用文中所提供的数据用谱带模型理论计算了2.7μ带在某些光学路径下光谱透过率和发射率,并将它们与实验测量结果相比较,两者符合得很好。     

Ab Initio方法研究NO分子红外光谱参数

分子光谱参数是红外辐射计算的基础数据,目前国内还没有类似HITRAN数据库的气体光谱数据库,在国家数值风洞工程的支持下,本文开发了高温空气光谱参数计算代码,目的是为目标红外辐射计算提供支持。NO是高超声速飞行器高温空气流场中的主要化学反应产物之一,其振转能级跃迁产生的辐射处于红外探测器的典型波段。本文基于ab initio计算的NO分子分裂后的分子势和永久偶极矩,计算了NO分子的线强度(温度达到了8000 K);在300 K和3000 K温度下,目前的理论计算结果与HITRAN数据库中的数据符合得非常好;本文还采用窄带模型计算了296 K和2000 K温度下NO分子X²Π_1/2态的吸收系数。目前所用方法可以不借助实验光谱常数,使低振动态和高振动态都得到比HITRAN数据库更多的线位置,可为国家数值风洞目标辐射特性计算提供NO分子高温光谱数据。     

CO_2分子4.3μ带谱带模型参数的理论计算

本文研究了CO_2分子4.3μ带谱带模型参数的计算方法,对积分带强度公式进行了修正,基于谱线积分线强度和谱线间隔表达式导出谱带模型参数:平均吸收系数(S/d)和谱线平均密度(1/d)的计算公式。并在很宽的温度范围内系统地计算了CO_2分子4.3μ带的谱带模型参数(S/d)和(1/d)。结果表明,低温下同位数~(13)CO_2对参数(S/d)的影响不可忽略,高温下必须考虑足够多“热带” 的贡献。 文中还应用统计谱带模型计算了各种光学路径下CO_2分子4.3μ带的发射光谱,其结果和实验光谱比较,符合甚好。     

自适应算法在极光系统参数估算中的应用

讨论带参数的自适应时域方法计算极光系统的参数,以一个有理形式函数模型来代表系统函数,采用可以在线实时应用的递推自适应算法来确定该模型的参数。利用这种方法处理测量所得的极光亮度数据,现用互谱方法计算的氧原子「ＯＩ３２」跃迁时Ｏ（＾１Ｓ）态的平均有效寿命符合得很好。     

氢化物AlH2自由基分子光谱辐射特征的研究

此文用以前计算的振动频率、转动常数和配分函数,再将常温下的无转动跃迁矩平方近似为一常数并应用于高温,进一步编制程序,计算了氢化物AlH2分子001-000跃迁带不同温度段的辐射强度和吸收系数等谱带辐射特征.配分函数的计算值与高斯程序计算及拟合值,在不同温度都吻合较好,这说明构建的模型是可靠的,可以用来进一步计算谱带强度和吸收系数;从获得不同温度段的模拟光谱辐射特征图也可以看出,本文得到的谱带特征与文献一致.这对进一步研究自由基分子高温光谱的实验和理论都具有一定的参考作用.     

高超声速飞行器气体辐射噪声计算方法

高超声速飞行器周围的激波层内高温气体会发生剧烈的物理化学变化,伴随强烈的光辐射过程,直接影响红外导引头的光学成像效果。采用流体力学Navier-Stokes方程和热化学非平衡模型模拟高温非平衡流动,考虑电子跃迁和振转跃迁以窄带法求解气体辐射特性参数,基于有限体积法离散辐射传输方程,在分别验证流场解算、辐射参数求解和辐射传输计算的基础上,进行了飞行器高速飞行的流动和辐射模拟。数值求解得到了飞行器流场特征和粒子数空间分布。计算的选定波长范围内的气体辐射发射系数空间分布显示其与激波形状和波后气体温度分布相似。通过传输得到的飞行器光学窗口视线路径上的气体辐射噪声成轴对称分布,发现辐射噪声和飞行速度、气体成分等密切相关,马赫数增加时气体辐射噪声显著增强。     

用STA模型计算Au等离子体的不透明度

 在局部热动平衡条件下,用STA（超组态跃迁阵）模型探索研究和计算Au等离子体在一定温度和密度下的跃迁阵的参数,并用来计算冲击压缩下等离子体的辐射不透明度。     

QUANTUM EFFICIENCY AND MULTIPHONON NONRADIATIVE TRANSITION OF Er3+ IONS IN FLUORIDE GLASS

Optical absorption, emission and excitation spectra, lifetimes of ⁴S_3/2 state and ⁴F_9/2 state from 10K to 500K, and Raman spectra were measured for Er³⁺ ions in fluoride glass. The radiative transition probabilities were calculated on the basis of Judd-Ofelt theory. The nonradiative transition probabilities and the quantum efficiencies were determined by calculating the difference between the measured lifetimes and the calculated radiative transition probabilities. The temperature dependence of nonradiative transition provavility was investigated using the Huang-Rhys theory of multiphonon relaxation , in which two kinds of phonons as well as the parameter s were taken into consideration. A fairly good agreement of the theoretical calculation with the experimental results has been obtained. The value of s is estimated and the effect of s is discussed.     

QUANTUM EFFICIENCY AND MULTIPHONON NONRADIATIVE TRANSITION OF Er3+ IONS IN FLUORIDE GLASS

Optical absorption, emission and excitation spectra, lifetimes of ⁴S_3/2 state and ⁴F_9/2 state from 10K to 500K, and Raman spectra were measured for Er³⁺ ions in fluoride glass. The radiative transition probabilities were calculated on the basis of Judd-Ofelt theory. The nonradiative transition probabilities and the quantum efficiencies were determined by calculating the difference between the measured lifetimes and the calculated radiative transition probabilities. The temperature dependence of nonradiative transition provavility was investigated using the Huang-Rhys theory of multiphonon relaxation , in which two kinds of phonons as well as the parameter s were taken into consideration. A fairly good agreement of the theoretical calculation with the experimental results has been obtained. The value of s is estimated and the effect of s is discussed.     

1.5μm处CO2与CO高温线强的实验分析与理论计算

本文在采用乘积近似方法计算二氧化碳、一氧化碳分子总的配分函数(其中分子的振动配分函数采用谐振子近似, 转动配分函数采用非刚性转子模型, 并考虑了离心扭曲修正)的基础上, 利用所得配分函数和振动跃迁矩平方的实验值以及Herman-Wallis系数, 计算了1.5 μm 附近二氧化碳30012–00001跃迁带和一氧化碳3–0跃迁带在300–6000 K温度范围内部分温度下的吸收线强; 为验证计算方法和结果的准确性, 在基于可调谐二极管激光吸收光谱技术搭建的高温测量系统中, 对300–800 K温度范围内部分谱线线强进行了测量, 并把计算结果、测量结果及HITRAN数据库中对应数据进行了对比, 发现相对偏差小于3%, 证明了本方法的有效性, 同时计算及测量所得高温线强数据可对HITRAN数据库进行有效的校正和补充.     

Narrow-band model for nonequilibrium air plasma radiation

A band model is developed for the prediction of radiative transfer in air plasma applications under equilibrium and non-equilibrium conditions. For non-equilibrium applications, the medium is described by rotational–translational and vibrational temperatures but the populations of electronic states can be arbitrary. A specific formulation of the statistical narrow-band (SNB) model is developed for optically thick electronic systems of diatomic molecules when their populations are described by an electronic temperature. Model parameters, deduced from line by line calculations in the Voigt regime, are shown to be also convenient for arbitrary distribution of molecular electronic populations. This model is then complemented to include optically thin electronic systems and the continuum radiation through the simple box model, and line by line calculations for atomic lines. Several tests including equilibrium, non-equilibrium, uniform, and non-uniform conditions show the ability of this hybrid model to provide accurate and efficient solutions for radiative transfer problems in air plasmas.     

Mössbauer and infrared spectroscopy as a diagnostic tool for the characterization of ferric tannates

The line shape of the (3p???1s) X-ray transition in muonic hydrogen was measured for the first time with a high-resolution crystal spectrometer. The assumption of a statistical population of the hyperfine levels was directly confirmed by experiment, and a measured value for the hyperfine splitting is reported. An X-ray line broadening due to Doppler effect could be clearly identified and attributed to different Coulomb de-excitation transitions which precede the measured radiative transition. The results allow a decisive test of advanced cascade model calculations and establish an alternative and “model free” method to extract the strong-interaction parameters from pionic hydrogen data.     

稀土掺杂固体发光材料的光谱分析

光谱分析是评价稀土发光材料光谱性质的主要依据,Judd-Ofelt(J-O)理论是光谱分析的基础。详述了采用J-O模型拟合三个强度参量和估算一些重要辐射参量的操作细节,讨论了相关公式的合理应用,总结了计算中误差的主要来源,并推荐了一种通过低温实验获得较可靠光谱参量的途径。建议采用透射光谱数据计算实验跃迁振子强度,吸收系数和吸收截面的计算应该扣除光反射、散射和基质本身吸收的影响,平均波数和平均波长的取值须考虑线形因子。并建议通过发射光谱的实测线形计算各波长的发射截面。由于J-O模型涉及许多近似和假设,计算结果误差较大,可能导致结果不可靠。通过分析指出,采用低温下测得的能级寿命和荧光分支比进行相关参量的估算可获得较可靠、较有意义的结果。     

Time-resolved Auger decay in CsBr using high harmonics

The temperature-dependent decay dynamics of innershell holes in CsBr was measured by using high harmonics. The measured lifetime was as short as 1.5 ps at 340 K due to increasing the Auger-allowed final state density in the Urbach exciton tail, whereas it is 1.1 ns at 10 K, determined by radiative recombination. The temperature-dependent Auger lifetime extrapolated to a high temperature corresponds to the fully energy-allowed Auger decay. In the model to be presented, this yields an interatomic Auger decay lifetime of 2.4+3.8/-1.5 fs, in line with a theoretical calculation for NaF.     

Luminescence of AgCl crystals at room temperature after ruby laser excitation

Emission spectrum of pure AgCl crystals at room temperature after ruby laser excitation was measured. The emission consists of a continuous fluorescence band with the maximum at about 460 nm which is at sufficiently high excitation intensities covered with characteristic line structure emission. The appearance of continous emission at this temperature was in accordance with experimental results explained by the increase of the radiative transition probability in AgCl crystals.