scholarly journals OPTICAL STUDIES OF PENICILLIN GROUP IN RELATION TO THEIR MEDICAL ACTIVITY

2017 ◽  
Vol 24 (4) ◽  
pp. 437-442
Author(s):  
R. Jeevan Kumar ◽  
G.V.R. Prasad ◽  
S.Md. Shoaib ◽  
G. Paul Devadanam ◽  
K. Fakruddin
Keyword(s):  
Cross Section ◽  
Molecular Interactions ◽  
Toxic Effects ◽  
Optical Methods ◽  
Molecular Polarizability ◽  
Refractive Indices ◽  
Optical Studies ◽  
Medical Activity ◽  
Ionisation Cross Section

The study of Medical activity of antibiotics is gaining momentum now a days owing to the importance of their curative values.  The Medical Activity correlated to molecular interactions,can be studied by various physical techniques, at present optical methods like Refractometry and Polarization are used to study the activity of a few antibiotics like Penicillin.  The Refractive Indices Mean Molecular Polarizability Diamagnetic Susceptibilities and Electron Ionisation Cross Section are interpreted in terms of dosages and the toxic effects if any due to over dosages are discussed critically.  

Measurements of the N2 2σu ou partial ionisation cross section via (e,2e) experiments

1999 ◽  
Vol 09 (PR6) ◽  
pp. Pr6-119-Pr6-122
Author(s):  
R. Flammin ◽  
E. Fainelli ◽  
L. Avaldi
Keyword(s):  
Cross Section ◽  
Ionisation Cross Section

Study of optical parameters of two fluorinated isothiocyanato nematic liquid crystals exhibiting high birefringence

2014 ◽  
Vol 22 (1) ◽  
Author(s):  
T. Devi ◽  
B. Choudhury ◽  
A. Bhattacharjee ◽  
R. Dabrowski
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Laser Beam ◽  
Order Parameter ◽  
Refractive Indices ◽  
Optical Parameters ◽  
Optical Studies ◽  
High Birefringence ◽  
Two Samples ◽  
Direct Extrapolation

AbstractOptical studies have been carried out on two fluorinated isothiocyanato nematic liquid crystal (LC) compounds 4′-butylcyclohexyl-3, 5-difluoro-4-isothiocyanatobiphenyl and 4′-pentylcyclohexyl-3, 5-difluoro-4-isothiocynatobiphenyl. Transition temperatures of the two samples were confirmed using a polarizing microscope. The two LC compounds were found to exhibit fairly high clearing temperatures. Measurements of refractive indices of the two compounds were done by using thin prism method with He-Ne laser beam of wavelength 630 nm. Birefringence of the two LC compounds was calculated from the measured refractive indices. Both the compounds are found to display fairly high values of birefringence. Validation of a modified four-parameter model, based on Vuks equation describing the temperature dependence of refractive indices of the two liquid crystals, is also presented in this paper. The model is validated by fitting the experimentally measured values of refractive indices, birefringence and average refractive indices of the two nematic LCs with the theoretical values. In this paper, the calculation of order parameters of the LCs is presented by using two methods: direct extrapolation method based solely on the birefringence data and by using modified Vuks method based on Haller’s extrapolation. As observed from the obtained results, this procedure of calculating order parameter gives very reasonable results.

STUDY OF HETEROMOLECULAR INTERACTION OF NONAQUEOUS BINARY SOLUTIONS

2020 ◽  
Vol 22 (2) ◽  
pp. 111-114
Author(s):  
D.T. Bozorova ◽  
Sh.P. Gofurov ◽  
A.M. Kokhkharov ◽  
O.B. Ismailova
Keyword(s):  
Binary Mixtures ◽  
Mole Fraction ◽  
Molecular Interactions ◽  
Weak Interactions ◽  
Structural Characteristics ◽  
Refractive Indices ◽  
Binary Solutions ◽  
Wide Range

In this work, the refractometry method was used to study of the molecular interactions and structural characteristics of dimethylformamide-ethanol and cyclohexane-ethanol binary mixtures. The refractive indices of mixtures were measured over a wide range of dimethylformamide and cyclohexane concentrations (0−1.0 mole fractions) at 25°С. It has been shown that heteromolecular complexes in binary solutions are formed at the concentration of ∼0.5 mole fraction of those compounds due to strong H-bonds. Relatively weak interactions are determined at a concentration of ∼0.2 and ∼0.9 mole fraction of dimethylformamide and ∼0.2 and ∼0.8 mole fraction of cyclohexane.

Soot Optical Properties in the Terahertz Spectra Domain

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Fei Wang ◽  
Ting Xu ◽  
Zhishen Qiang ◽  
Qunxing Huang ◽  
Dong Liu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Time Domain ◽  
Wavelength Region ◽  
Optical Methods ◽  
Optical Data ◽  
Refractive Indices ◽  
Spectroscopy Technique ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Combustion Diagnostics

For understanding and accurately modeling combustion, the important questions are what species are present in the flame, and the spatial distribution and temperature of these species. Traditional optical methods used only the electromagnetic waves in the wavelength region from the ultraviolet region up to the infrared. Terahertz time-domain spectroscopy technique can be used for the combustion research as a novel tool. However, for some sooty combustion environments, the strong absorption, spectral interference from soot scattering, and fluorescence from large molecules must be considered. The optical properties of soot in the terahertz domain are the main basic data for terahertz application. In this paper, the terahertz time-domain spectroscopy technique was used to study the optical properties of flame soot within 0.2–1.6 THz. The complex refractive indices of the soot were deduced by the fixed-point iteration method. In order to validate the results, the complex refractive indices of the soot from the four different fuel flames were deduced. It was found that the complex refractive indices in the terahertz domain of the soot from the different fuel flames are very close to each other. The comparisons of complex refractive indices between the visible–IR domain and the terahertz domain indicate that the value of absorption index in terahertz domain is smaller than in IR domain, which implies that the terahertz wave will penetrate the sooty flame with smaller absorption than the IR rays. The results can provide the basic optical data of flame soot for the application of terahertz time-domain spectroscopy technique in the optical combustion diagnostics and extend the optical combustion diagnostics application area.

scholarly journals The indicator method for the determination of coefficient of diffusion in gels, with special reference to the diffusion of chlorides

1923 ◽  
Vol 103 (721) ◽  
pp. 260-275 ◽  
Keyword(s):  
Cross Section ◽  
Optical Rotation ◽  
Essential Feature ◽  
Optical Methods ◽  
Indicator Method ◽  
Definite Time ◽  
Special Apparatus ◽  
Different Levels ◽  
Coefficient Of Diffusion

Since the original investigations of Thomas Graham on the diffusion of dissolved substances in water a number of methods have been evolved and used for the determination of coefficients of diffusion of solutes in water. The essential Feature of all these methods is the estimation of the quantity of dissolved substance after the lapse of a definite time in different lasers of a cylinder of water through which the solute is diffusing, the calculation of the coefficient then being made on the assumption of Fick's law, which defines the coefficient of diffusion as D in the equation d Q = -DA δc/δx dt where d Q is the quantity of solute diffusing through a cross-section of the cylinder in the time at a point where the concentration gradient is δc/δ x and A is the cross-section of the cylinder. A variety of methods have been used for estimating the concentration of the solution at different levels, these methods including chemical analysis of the lasers, specific gravity determinations, optical methods, such as determination of refractive index or optical rotation, determinations of electrical conductivity, and other electrical methods. These methods for the most part require special apparatus, and the determinations are not always easy to make. These are not, of course, to be regarded as drawbacks, but a glance at the results obtained by their means as summerised, for example, in Landolt and Börnstein's tables, is sufficient to give an impression of unreliability since the determinations of different workers often show very considerable divergence.

Note on the Refrative Indices of Pyromorphite, Mimetite, and Vanadinite

1903 ◽  
Vol 13 (62) ◽  
pp. 324-329 ◽  
Author(s):  
H. L. Bowman
Keyword(s):  
Cross Section ◽  
Refractive Indices ◽  
Optical Examination

It is somewhat remarkable that a group of minerals, of which such excellent transparent crystals are known as of pyromorphite, mimetite, and vanadinite, should not have hitherto been submitted to a detailed optical examination, except as regards the nature of the interference figures visible in a cross-section. The only reference to the refractive indices of these substances, which I have been able to find, is one by Schroeder van der Kolk, who states that those of pyromorphite amt vanadinite are above 1.93 (as found by immersion in highly refracting liquids), and that they have a birefringence of 0.02 and 0.01 respectively.

The pressure dependence of refractivity of polar gases

1960 ◽  
Vol 255 (1282) ◽  
pp. 427-433 ◽  
Keyword(s):  
Pressure Dependence ◽  
Sulphur Dioxide ◽  
Experimental Error ◽  
Methyl Chloride ◽  
Molecular Polarizability ◽  
Refractive Indices ◽  
Methyl Fluoride ◽  
Carbon Tetrafluoride ◽  
First Order

The refractive indices of several gases have been measured at varying pressures in the range 0 to 50 cm. For carbon tetrafluoride, methyl fluoride and methyl chloride the refractivity varies directly with the density within the limits of experimental error. For ammonia and sulphur dioxide the increase of refractivity with pressure is less than would correspond to the increase in density. This may be interpreted in terms of a negative ‘first-order hyperpolarizability' for the polar vapours, whose molecular polarizability is being decreased by the influence of the field due to neighbouring molecular dipoles.

Measurement of the Excited-State Molecular Polarizability of C60

1994 ◽  
Vol 359 ◽  
Author(s):  
N. Tang ◽  
R. W. Hellwarth ◽  
J. P. Partanen
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Benzene Solution ◽  
Excited State Absorption ◽  
Molecular Polarizability ◽  
Wave Mixing ◽  
Pump Probe ◽  
Probe Experiment ◽  
Pump Probe Experiment ◽  
532 Nm

ABSTRACTWe use ∼30 ps pulses at 532 nm to measure the complex excited-state molecular polarizability αe in a C60/benzene solution. We determine the imaginary part of αe by measuring the excited-state absorption cross-section in a pump-probe experiment. In a degenerate-four-wave-mixing (DFWM) experiment, we find that in delayed probing of the complex index gratings formed by ∼30 ps pulses, the thermal and the excited-state polarizability changes both contribute to these transient gratings.

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