Diffuse component of the fluorescence spectrum of anthracene vapor as a function of the frequency of the exciting radiation

1999 ◽  
Vol 66 (5) ◽  
pp. 733-737
Author(s):  
E. A. Vandyukov
Keyword(s):  
Fluorescence Spectrum ◽  
Exciting Radiation ◽  
Diffuse Component ◽  
Anthracene Vapor

Effect of reabsorption on the fluorescence spectra of chlorophyll-a

1984 ◽  
Vol 49 (2) ◽  
pp. 474-480 ◽  
Author(s):  
Marie Urbanová ◽  
Jan Nauš ◽  
Jan Hála ◽  
Ludvík Parma
Keyword(s):  
Fluorescence Spectrum ◽  
Chlorophyll A ◽  
Simple Formula ◽  
Fluorescence Spectra ◽  
Exciting Radiation ◽  
Experimental Arrangement ◽  
Pigment Concentrations ◽  
Strong Distortion ◽  
Qualitative Picture

Simple formula for the reabsorption correction was tested on the fluorescence spectra of thin polystyrenefoils with built-in chlorophyll-a. The spectra were studied at various pigment concentrations, wavelengths and angles of incidence of the exciting radiation. It is shown that neglecting the reabsorption effect in dependence of the experimental arrangement can lead to a strong distortion of the fluorescence spectrum. The derived formula yields a good qualitative picture of the fluorescence spectra.

Fluorescence effects in quantitative microprobe analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 188-189
Author(s):  
S.J.B. Reed
Keyword(s):  
Microprobe Analysis ◽  
Depth Distribution ◽  
Exciting Radiation ◽  
Primary Radiation ◽  
List Type ◽  
Type Number ◽  
Computing Power ◽  
X Ray ◽  
Fluorescent Radiation

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.

Chloroplast Ultrastructure and Emission Fluorescence Spectrum Characteristics for Stems of Phyllostachys pubescens

2014 ◽  
Vol 48 (6) ◽  
pp. 635-642
Author(s):  
Chen Dengju ◽  
Gao Peijun ◽  
Wu Xingbo ◽  
Gao Yan ◽  
Wen Guosheng ◽  
...  
Keyword(s):  
Fluorescence Spectrum ◽  
Chloroplast Ultrastructure ◽  
Phyllostachys Pubescens ◽  
Spectrum Characteristics

scholarly journals Using the Method of “Optical Biopsy” of Prostatic Tissue to Diagnose Prostate Cancer

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1961
Author(s):  
Dmitry N. Artemyev ◽  
Vladimir I. Kukushkin ◽  
Sofia T. Avraamova ◽  
Nikolay S. Aleksandrov ◽  
Yuri A. Kirillov
Keyword(s):  
Prostate Cancer ◽  
Glutamic Acid ◽  
Raman Spectra ◽  
Aerobic Glycolysis ◽  
Exciting Radiation ◽  
Optical Biopsy ◽  
Strong Increase ◽  
Fundamental Factor ◽  
Diagnose Prostate Cancer ◽  
Latent Structures

The possibilities of using optical spectroscopy methods in the differential diagnosis of prostate cancer were investigated. Analytical discrimination models of Raman spectra of prostate tissue were constructed by using the projections onto latent structures data analysis(PLS-DA) method for different wavelengths of exciting radiation—532 and 785 nm. These models allowed us to divide the Raman spectra of prostate cancer and the spectra of hyperplasia sites for validation datasets with the accuracy of 70–80%, depending on the specificity value. Meanwhile, for the calibration datasets, the accuracy values reached 100% for the excitation of a laser with a wavelength of 785 nm. Due to the registration of Raman “fingerprints”, the main features of cellular metabolism occurring in the tissue of a malignant prostate tumor were confirmed, namely the absence of aerobic glycolysis, over-expression of markers (FASN, SREBP1, stearoyl-CoA desaturase, etc.), and a strong increase in the concentration of cholesterol and its esters, as well as fatty acids and glutamic acid. The presence of an ensemble of Raman peaks with increased intensity, inherent in fatty acid, beta-glucose, glutamic acid, and cholesterol, is a fundamental factor for the identification of prostate cancer.

scholarly journals Retrieving Sun-Induced Chlorophyll Fluorescence from Hyperspectral Data with TanSat Satellite

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4886
Author(s):  
Shilei Li ◽  
Maofang Gao ◽  
Zhao-Liang Li
Keyword(s):  
Chlorophyll Fluorescence ◽  
Fluorescence Spectrum ◽  
Singular Vector ◽  
Low Frequency ◽  
Information Criterion ◽  
Hyperspectral Data ◽  
High Spectral Resolution ◽  
Remotely Sensed Data ◽  
Spectral Window ◽  
Vector Decomposition

A series of algorithms for satellite retrievals of sun-induced chlorophyll fluorescence (SIF) have been developed and applied to different sensors. However, research on SIF retrieval using hyperspectral data is performed in narrow spectral windows, assuming that SIF remains constant. In this paper, based on the singular vector decomposition (SVD) technique, we present an approach for retrieving SIF, which can be applied to remotely sensed data with ultra-high spectral resolution and in a broad spectral window without assuming that the SIF remains constant. The idea is to combine the first singular vector, the pivotal information of the non-fluorescence spectrum, with the low-frequency contribution of the atmosphere, plus a linear combination of the remaining singular vectors to express the non-fluorescence spectrum. Subject to instrument settings, the retrieval was performed within a spectral window of approximately 7 nm that contained only Fraunhofer lines. In our retrieval, hyperspectral data of the O2-A band from the first Chinese carbon dioxide observation satellite (TanSat) was used. The Bayesian Information Criterion (BIC) was introduced to self-adaptively determine the number of free parameters and reduce retrieval noise. SIF retrievals were compared with TanSat SIF and OCO-2 SIF. The results showed good consistency and rationality. A sensitivity analysis was also conducted to verify the performance of this approach. To summarize, the approach would provide more possibilities for retrieving SIF from hyperspectral data.

Excitation of transitions between atomic or molecular energy levels by monochromatic laser radiation - II. Excitation under conditions of strictly inhomogeneous line broadening and mixed homogeneous and inhomogeneous broadening

1978 ◽  
Vol 362 (1708) ◽  
pp. 13-25 ◽  
Keyword(s):  
Laser Radiation ◽  
Line Width ◽  
Energy Levels ◽  
Incident Radiation ◽  
Exciting Radiation ◽  
Half Line ◽  
Line Broadening ◽  
Moment Matrix ◽  
Inhomogeneous Line Broadening ◽  
Inhomogeneous Line

The development with time of the excitation of a transition between two atomic or molecular energy levels under the influence of monochromatic laser radiation is examined under conditions of strictly inhomogeneous line broadening due to such causes as doppler shift arising from translational velocity. The ratio of the number of molecules, N 2 , in an excited state to the total number, N , is calculated for various ratios of the intensity parameter β ═ E 0 μ / ħ to the half line-width ∆ , where E 0 is the amplitude of the electric field in the incident radiation and is the dipole moment matrix element for the transition. Excitation functions obtained in a previous paper (I) for various values of the ratio γ/β , where γ is the half line-width in the absence of inhomo­geneous broadening, are used to obtain the variation of N 2 / N with time under conditions of mixed broadening for various values of the ratio γ/∆ and γ/β , when the exciting radiation is in exact resonance with the central frequency of the transition.

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