scholarly journals Влияние неопределенности значений вероятностей спонтанного излучения на температурное поведение коэффициентов ударного самоуширения спектральных линий молекул CO-=SUB=-2-=/SUB=-

2020 ◽  
Vol 128 (10) ◽  
pp. 1518
Author(s):  
К.И. Аршинов ◽  
В.В. Бобровский ◽  
О.Н. Крапивная ◽  
В.Н. Шут
Keyword(s):  
Inverse Problem ◽  
Temperature Dependence ◽  
Spectral Lines ◽  
Spontaneous Radiation ◽  
Absorption Coefficients ◽  
Method Of Least Squares ◽  
Joint Determination ◽  
Temperature Dependences ◽  
Radiation Probability

The influence of the deviation of the spontaneous radiation probability of the spectral lines of CO2 A on the temperature dependence of the collisional self-broadened coefficients γ in solving the inverse problem of joint determination of A and γ from the array of absorption coefficients is studied. The study was carried out for two cases: 1) A=0.2022 s-1 (HITRAN2012); 2) the values of A were obtained by minimizing the sum of weighted squares of the absorption coefficients differences. It was found that in the temperature range of 300-700 K, when the absorption coefficients are measured with accuracy 0.05∙αmin, the deviation of the functions γ(T) does not exceed 5%. There is no causal relationship between the parameters γ and A. The method of least squares allows us to correctly calculate the temperature dependences of the collisional self-broadened coefficients of the CO2 lines γ(T).

Inverse technique for determining temperature dependence of material properties

2017 ◽  
Vol 36 (2) ◽  
pp. 427-435
Author(s):  
David Pánek ◽  
Václav Kotlan ◽  
Roman Hamar ◽  
Ivo Doležel
Keyword(s):  
Inverse Problem ◽  
Temperature Dependence ◽  
Material Parameter ◽  
Physical Parameters ◽  
Saturation Curve ◽  
Temperature Dependent ◽  
Content Type ◽  
Steel Material ◽  
Temperature Dependences ◽  
Accuracy Of Results

Purpose This paper aims to present a methodology of finding temperature dependencies of selected physical parameters of metals. The method is based on the combination of measurement of the surface temperature of material during the process of heating and subsequent solution of the inverse problem using multi-parametric optimization. Design/methodology/approach The methodology is based on measurements and numerical solution of the forward and inverse problem, taking into account all involved nonlinearities (saturation curve of the processed steel material and temperature dependences of its physical parameters). The inverse problem is solved by a genetic algorithm. Findings The suggested methodology was successfully verified on several metal materials whose temperature-dependent parameters are known. The calculated and measured results exhibit a very good accordance (the differences do not exceed about 10 per cent for room and higher temperatures). Research limitations/implications At this moment, the methodology successfully works when the temperature dependence of just one material parameter is to be found (which means that the temperature dependencies of other parameters are known). The accuracy of results also depends on the correctness of other input data. Practical implications This paper provides a relatively easy possibility of finding the temperature dependencies of thermal conductivity or heat capacity of various alloys. Originality/value The paper proposes a methodology of finding the temperature dependence of a given material parameter that is not known in advance (which is of great importance in case of alloys).

Temperature dependence of linear electrooptic coefficients r 113 and r 333 in lithium niobate

2008 ◽  
Vol 16 (1) ◽  
Author(s):  
P. Górski ◽  
R. Ledzion ◽  
K. Bondarczuk ◽  
W. Kucharczyk
Keyword(s):  
Lithium Niobate ◽  
Temperature Dependence ◽  
New Method ◽  
Refractive Indices ◽  
Temperature Range ◽  
Method Of Determination ◽  
Induced Polarisation ◽  
Temperature Dependences

AbstractA new method of determination of individual linear electrooptic coefficients is proposed. The technique is based on the dynamic polarimetric measurements and takes into consideration the temperature dependences of ordinary and extraordinary refractive indices. Results obtained for the electrooptic coefficients r113 and r333 in LiNbO3 are presented. The coefficients are found to increase significantly within the considered temperature range 25-200°C. The temperature dependences of the intrinsic coefficients m113 and m333, defined in terms of the induced polarisation, are considered as well.

Temperature Dependences in the O + OH → O2 + H Reaction. Quasiclassical Trajectory Calculation

1993 ◽  
Vol 58 (2) ◽  
pp. 234-243 ◽  
Author(s):  
Viliam Klimo ◽  
Martina Bittererová ◽  
Stanislav Biskupič ◽  
Ján Urban ◽  
Miroslav Micov
Keyword(s):  
Temperature Dependence ◽  
Energy Surface ◽  
Analytical Form ◽  
Mean Values ◽  
Quantum Numbers ◽  
Mean Lifetime ◽  
Temperature Dependences ◽  
Quasiclassical Trajectory Calculation ◽  
The Mean ◽  
Combustion Processes

The reaction O + OH → O2 + H in conditions of combustion of hydrocarbons and polymers was modelled by using the method of quasiclassical trajectories. The potential energy surface was determined by the multiconfiguration interaction method and fitted with the analytical form of the extended LEPS function. Attention was paid to the mean values of the vibrational and rotational quantum numbers of O2 molecules and their temperature dependence. The temperature dependence of the mean lifetime of the OOH collision complex was also examined. The calculated rate constants were analyzed and compared with the experimental data over the temperature region of the combustion processes.

The Urbach Rule for the Sodium- and Potassium-Halides

1974 ◽  
Vol 29 (1) ◽  
pp. 145-157 ◽  
Author(s):  
Tetsuhiko Tomiki ◽  
Takeo Miyata ◽  
Hirokazu Tsukamoto
Keyword(s):  
Temperature Dependence ◽  
Acoustic Phonon ◽  
Frequency Factor ◽  
Host Lattice ◽  
Exciton Peak ◽  
Urbach Rule ◽  
Temperature Dependences ◽  
Hole Band ◽  
Sodium And Potassium ◽  
Potassium Halides

Phenomenological and physical aspects of the intrinsic tail spectra of the alkalihalides are studied referring to the new results on the intrinsic tail spectra of KBr and KI and to the temperature dependences of the lowest-energy Γ-exciton peak of the sodium- and potassium-halides. Systematically analysing the temperature dependence of the steepness parameter σs (T) of the Urbach rule for these halides, it is found that the frequency factor has the value nearly equal to the acoustic phonon energy at X or L of each host lattice and the steepness constant σs0 becomes larger in passing from fluoride to iodide. This halogen dependence of σs0 is discussed in terms of the hole band-mass of the Γ8-level.

scholarly journals The Semiclassical Limit of the Gailitis Formula Applied to Electron Impact Broadening of Spectral Lines of Ionized Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Sylvie Sahal-Bréchot
Keyword(s):  
Electron Impact ◽  
Classical Limit ◽  
Semiclassical Limit ◽  
Spectral Lines ◽  
Stark Broadening ◽  
Feshbach Resonances

The present paper revisits the determination of the semi-classical limit of the Feshbach resonances which play a role in electron impact broadening (the so-called “Stark“ broadening) of isolated spectral lines of ionized atoms. The Gailitis approximation will be used. A few examples of results will be provided, showing the importance of the role of the Feshbach resonances.

Determination of an impulsive diffusion operator from interior spectral data

Analysis ◽  
2020 ◽  
Vol 40 (1) ◽  
pp. 39-45
Author(s):  
Yasser Khalili ◽  
Dumitru Baleanu
Keyword(s):  
Inverse Problem ◽  
Spectral Data ◽  
Potential Functions ◽  
Half Line ◽  
Internal Point ◽  
Diffusion Operator ◽  
Impulsive Diffusion

AbstractIn the present work, the interior spectral data is used to investigate the inverse problem for a diffusion operator with an impulse on the half line. We show that the potential functions {q_{0}(x)} and {q_{1}(x)} can be uniquely established by taking a set of values of the eigenfunctions at some internal point and one spectrum.

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