Optical absorption and fluorescence studies of Dy3+-doped lead telluroborate glasses

2012 ◽  
Vol 132 (1) ◽  
pp. 86-90 ◽  
Author(s):  
M.V. Vijaya Kumar ◽  
B.C. Jamalaiah ◽  
K. Rama Gopal ◽  
R.R. Reddy
Keyword(s):  
Optical Absorption ◽  
Fluorescence Studies

Effect of Cis-Backbone on Optical Properties of Polyphenylacetylene

2010 ◽  
Vol 428-429 ◽  
pp. 483-486
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Intermolecular Interactions ◽  
Density Of States ◽  
Tight Binding ◽  
Binding Theory ◽  
Concentrated Solutions ◽  
Fluorescence Studies ◽  
Excited Complex ◽  
Blue Photoluminescence

By controlling the temperature of chemical reaction, we synthesized four polyphenylacetylene samples, in which the percentages of cis configurations were determined to be 65, 75, 85 and 100%, respectively. Ultraviolet-visible and fluorescence studies show that the cis-configured backbones have posed significant effects on the optical absorption and fluorescence of the polyphenylacetylenes. Upon the 325-nm excitation, the dilute solutions of these cis-polyphenylacetylenes give off weak fluorescence with their peak located at about 390 nm, but the concentrated solutions of the polymer can give off strong orange-red fluorescence with their peak located at about 600 nm. With Hückel tight binding theory, both the E-k dispersion relations and the density of states were calculated for cis-polyphenylacetylene. Our results suggest that the blue photoluminescence of polyacetylenes origins from the backbone enhanced -conjugation of the phenyl chromophors in the polymer, and that intermolecular interactions can occur in the excited complex of the polymer.

Effect of preferential solvation and bimolecular quenching reactions on 3OCE in acetonitrile and 1,4‐dioxane binary mixtures by optical absorption and fluorescence studies

Luminescence ◽  
2019 ◽  
Vol 34 (8) ◽  
pp. 924-932 ◽  
Author(s):  
V.T. Muttannavar ◽  
Raveendra Melavanki ◽  
Kalpana Sharma ◽  
S. Vaijayanthimala ◽  
Vikas M. Shelar ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Binary Mixtures ◽  
Preferential Solvation ◽  
Fluorescence Studies ◽  
Bimolecular Quenching

Thermoluminescence, fluorescence, and optical absorption studies on single crystals of rubidium iodide doped with Eu2+

1985 ◽  
Vol 63 (4) ◽  
pp. 517-521 ◽  
Author(s):  
K. L. Tan ◽  
S. Sapru ◽  
S. B. S. Sastry
Keyword(s):  
Optical Absorption ◽  
Emission Spectra ◽  
Energy Band Diagram ◽  
Band Diagram ◽  
Fluorescence Studies ◽  
Fluorescence Measurements ◽  
Absorption Studies ◽  
Order Of Magnitude ◽  
Optical Treatment ◽  
The Eu

Thermoluminescence, optical absorption, and fluorescence studies on the RbI:Eu2+ system indicate that the Eu2+ ions act as donors on irradiation and thereby convert to the Eu3+ ions. On thermal and (or) optical treatment the electrons released are captured back. The integrated light intensity of the system is an order of magnitude higher than that of the undoped samples. Fluorescence measurements show an emission around 2.83 eV. Thermoluminescence emission spectra give two emission bands peaking around 2.48 and 2.83 eV. A tentative energy band diagram is suggested explaining these emissions. Excitation of irradiated samples with F light is used to support this model.

Correlative video enhanced differential interference contrast light microscopy (VDIC)-LM), low-voltage high-resolution SEM (LV-HR-SEM), and high-voltage electron microscopy (HVEM) in the observation of gold-labelled surface antigens and the subjacent cytoskeletal matrix

1989 ◽  
Vol 47 ◽  
pp. 904-905
Author(s):  
Ralph M. Albrecht ◽  
Scott R. Simmons ◽  
Marek Malecki
Keyword(s):  
High Resolution ◽  
Light Microscopy ◽  
Low Voltage ◽  
Microscopic Analysis ◽  
Cell Labelling ◽  
Video Technology ◽  
Electron Microscopic ◽  
Image Capture ◽  
High Voltage Electron Microscopy ◽  
Fluorescence Studies

The development of video-enhanced light microscopy (LM) as well as associated image processing and analysis have significantly broadened the scope of investigations which can be undertaken using (LM). Interference/polarization based microscopies can provide high resolution and higher levels of “detectability” especially in unstained living systems. Confocal light microscopy also holds the promise of further improvements in resolution, fluorescence studies, and 3 dimensional reconstruction. Video technology now provides, among other things, a means to detect differences in contrast difficult to detect with the human eye; furthermore, computerized image capture, processing, and analysis can be used to enhance features of interest, average images, subtract background, and provide a quantitative basis to studies of cells, cell features, cell labelling, and so forth. Improvements in video technology, image capture, and cost-effective computer image analysis/processing have contributed to the utility and potential of the various interference and confocal microscopic instrumentation.Electron microscopic technology has made advances as well. Microprocessor control and improved design have contributed to high resolution SEMs which have imaging capability at the molecular level and can operate at a range of accelerating voltages starting at 1KV. Improvements have also been seen in the HVEM and IVEM transmission instruments. As a whole, these advances in LM and EM microscopic technology provide the biologist with an array of information on structure, composition, and function which can be obtained from a single specimen. Corrrelative light microscopic analysis permits examination of living specimens and is critical where the “history” of a cell, cellular components, or labels needs to be known up to the time of chemical or physical fixation. Features such as cytoskeletal elements or gold label as small as 0.01 μm, well below the 0.2 μm limits of LM resolution, can be “detected” and their movement followed by VDIC-LM. Appropriate identification and preparation can then lead to the examination of surface detail and surface label with stereo LV-HR-SEM. Increasing the KV in the HR-SEM while viewing uncoated or thinly coated specimens can provide information from beneath the surface as well as increasing Z contrast so that positive identification of surface and subsurface colloidal gold or other heavy metal labelled/stained material is possible. Further examination of the same cells using stereo HVEM or IVEM provides information on internal ultrastructure and on the relationship of labelled material to cytoskeletal or organellar distribution, A wide variety of investigations can benefit from this correlative approach and a number of instrumentational configurations and preparative pathways can be tailored for the particular study. For a surprisingly small investment in time and technique, it is often possible to clear ambiguities or questions that arise when a finding is presented in the context of only one modality.

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