CANALISATION D'ONDES ÉLECTROMAGNÉTIQUES PAR DIFFRACTION ITÉRÉE

1963 ◽  
Vol 41 (10) ◽  
pp. 1604-1613 ◽  
Author(s):  
Germain Boivin ◽  
Réal Tremblay
Keyword(s):  
Visible Region ◽  
Periodic Sequence ◽  
Wave Guide ◽  
Beam Power ◽  
Low Loss ◽  
Amplitude Function ◽  
Beam Wave ◽  
Microwave Beam ◽  
Varied Function

The determination of a state of steady wave propagation through a periodic sequence of lenses with minimal beam power loss is based on a previously published study of encircled energy in the visible region. The amplitude function T(x) derived from an extremum of the factor of encircled energy E(W) for a fixed abscissa W = Wm = 5 can be replaced with sufficient accuracy by the varied function [Formula: see text]; the periodic sequence of lenses illuminated by a field distribution [Formula: see text] is analogous to a low-loss beam wave guide.With regard to this theoretical analysis and practical application, the authors describe the characteristics of a beam wave guide for millimeter waves which maintains an optimum compromise between diffraction losses and line dimensions. This analysis is completed by experimental results from a microwave beam wave guide operating at the 1.25 cm wavelength.

scholarly journals Development of new spectrophotometric method for estimation of tenofovir disoproxil fumarate using MBTH reagent

2015 ◽  
Vol 4 (4) ◽  
pp. 378-381 ◽  
Author(s):  
Mannem Sri Varsha ◽  
N. Raghavendra Babu ◽  
Yenumula Padmavathi ◽  
P. Ravi Kumar
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Visible Region ◽  
Pharmaceutical Formulations ◽  
Pharmaceutical Journal ◽  
Specific Procedure ◽  
Analytical Validation ◽  
Pharmaceutical Dosage Forms ◽  
Secondary Amine Group ◽  
Validation Procedure

A new simple, sensitive and specific procedure has been developed for determination of tenofovir disoproxil fumarate in bulk and pharmaceutical dosage forms using MBTH reagent. The purpose of this analytical validation procedure is to validate it by laboratory experiments to prove that the method meets the minimum standards for laboratory use. 3-methyl-2-bezothiazoline hydrazone reacts with the secondary amine group of tenofovir in the presence of oxidizing agent, ferric chloride. The resulting apple green coloured chromogen when measured spectrophotometrically in visible region (i.e., 400-800nm) shows a maximum absorbance at 626.5nm. This method can be successfully applied for the determination of drug content in pharmaceutical formulations. The results of analysis have been validated statistically.DOI: http://dx.doi.org/10.3329/icpj.v4i4.22620 International Current Pharmaceutical Journal, March 2015, 4(4): 378-381 

Two Stage Gain Magnification in Beam Wave Guide Feed of Indian Deep Space Network (IDSN-32) Station

2012 ◽  
Vol 60 (7) ◽  
pp. 3481-3484
Author(s):  
V. V. Srinivasan ◽  
C. Kumar ◽  
D. Bhatnagar ◽  
V. K. Lakshmeesha ◽  
S. Pal
Keyword(s):  
Wave Guide ◽  
Deep Space ◽  
Two Stage ◽  
Deep Space Network ◽  
Beam Wave ◽  
Space Network

Terminology, relative photonic efficiencies and quantum yields in heterogeneous photocatalysis. Part II: Experimental determination of quantum yields

1999 ◽  
Vol 71 (2) ◽  
pp. 321-335 ◽  
Author(s):  
Angela Salinaro ◽  
Alexei V. Emeline ◽  
Jincai Zhao ◽  
Hisao Hidaka ◽  
Vladimir K. Ryabchuk ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Visible Region ◽  
Heterogeneous Photocatalysis ◽  
Quantum Yields ◽  
Yield Data ◽  
Normal Absorption ◽  
The One ◽  
Solid Liquid ◽  
Photonic Efficiency

In the preceding article [Serpone and Salinaro, Pure Appl. Chem., 71(2), 303-320 (1999)] we examined two principal features of heterogeneous photocatalysis that demanded scrutiny: (i) description of photocatalysis and (ii) description of process efficiencies. For the latter we proposed a protocol relative photonic efficiency which could subsequently be converted to quantum yields. A difficulty in expressing a quantum yield in heterogeneous photochemistry is the very nature of the system, either solid/liquid or solid/gas, which places severe restrictions on measurement of the photon flow absorbed by the light harvesting component, herein the photocatalyst TiO2, owing to non-negligible scattering by the particulates. It was imperative therefore to examine the extent of this problem. Extinction and absorption spectra of TiO2 dispersions were determined at low titania loadings by normal absorption spectroscopy and by an integrated sphere method, respectively, to assess the extent of light scattering. The method is compared to the one reported by Grela et al. [J. Phys. Chem., 100, 16940 (1996)] who used a polynomial extrapolation of the light scattered in the visible region into the UV region where TiO2 absorbs significantly. This extrapolation underestimates the scattering component present in the extinction spectra, and will no doubt affect the accuracy of the quantum yield data. Further, we report additional details in assessing limiting photonic efficiencies and quantum yields in heterogeneous photocatalysis.

scholarly journals NEW, GREEN AND MINIATURIZED ANALYTICAL METHOD FOR DETERMINATION OF CEFADROXIL MONOHYDRATE IN CAPSULES

2019 ◽  
Vol 3 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Bianca Marco ◽  
Ana Kogawa ◽  
Hérida Salgado
Keyword(s):  
Analytical Chemistry ◽  
Standard Sample ◽  
Low Cost ◽  
Visible Region ◽  
Hplc Method ◽  
Minimal Amount ◽  
Green Analytical Chemistry ◽  
Color Reagent ◽  
Routine Quality Control

Cefadroxil, an oral antimicrobial, presents few techniques optimized for the reduction of solvents and toxic residues and/or non-use of them. So, a quantitative, new and miniaturized method for determination of cefadroxil monohydrate in capsules has been developed and validated by spectrophotometric method in the visible region according to the international guidelines. The analyzes were performed using microplates containing 96 wells, 1 % of phenolphthalein and sodium hydroxide 0.1 M as reagent at 552 nm. The method was (i) linear in the range of 15-115 µg mL-1, (ii) selective when comparing standard, sample, adjuvants and color reagent, (iii) precise with deviations below 4 %, (iv) accurate when comparing the proposed method with the HPLC method, (v) robusts by making small and deliberate modifications to the method, (vi) besides being fast, low cost, eco-friendly and generates minimal amount of waste. The method can be applied to the routine quality control of cefadroxil monohydrate in capsules and an effective and accessible alternative that contemplates the concepts of current and sustainable green analytical chemistry.

THE EMISSION SPECTRUM OF THE PbBr MOLECULE

1967 ◽  
Vol 45 (11) ◽  
pp. 3663-3666 ◽  
Author(s):  
K. M. Lal ◽  
B. N. Khanna
Keyword(s):  
Emission Spectrum ◽  
Visible Region ◽  
Second Order ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Concave Grating

The emission spectrum of the A–X system of the PbBr molecule in the region 4 600–5 900 Å has been obtained in the second order of a 21-ft concave grating spectrograph (15 000 lines per inch) with a dispersion of 1.25 Å/mm. A rotational analysis of four bands—(3, 2), (2, 2), (3, 1), and (4, 1)—of this system has been done, leading to the determination of the following rotational constants:[Formula: see text]The system appears to be similar to the A-X system of the PbCl molecule in the visible region, and a [Formula: see text] transition has been suggested.

scholarly journals Microspectrophotometric Determination of Nonheme Iron in Maturing Erythroblasts and its Relationship to the Endocellular Hemoglobin Formation

Blood ◽  
1960 ◽  
Vol 16 (3) ◽  
pp. 1285-1297 ◽  
Author(s):  
C. A. SONDHAUS ◽  
BO THORELL
Keyword(s):  
Single Cells ◽  
Cell Mass ◽  
Visible Region ◽  
Hemoglobin Concentration ◽  
Nonheme Iron ◽  
Stable Form ◽  
Intracellular Iron ◽  
Experimental Conditions ◽  
Near Ultraviolet

Abstract The strong near-UV absorption of inorganic iron makes possible the microspectrophotometric determination of nonheme intracellular iron as distinct from hemoglobin-bound iron. Erythroid cells of Salamandra Maculosa were therefore studied microspectrophotometrically in the near ultraviolet and visible region. Absorption curves from cytoplasmic areas in living and dried cells were obtained from 310 to 700 mµ., and two component analyses were made to determine the presence and amount of hemoglobin and nonhemoglobin absorption. Under the experimental conditions, intracellular hemoglobin was present largely as the carbon monoxide derivative, a stable form which provided a well defined standard to correct for nonspecific absorption and other spectral distortion due to the optical properties of single cells. Absorption curves from the youngest cells measured were found to differ from those of mature cells, the difference curve agreeing most closely with that of inorganic iron or ferritin in solution. In the youngest cells, nonheme iron appeared to exceed 6 per cent by weight of hemoglobin, or over 20 times molar hemoglobin concentration, dropping and remaining at about twice the hemoglobin molarity from the time hemoglobin synthesis was one-third complete until maturity. Allowing for the increase of total cell mass with growth, the data suggest that although young erythroblasts may already have enough Fe for subsequent Hb synthesis, they continue to incorporate excess Fe throughout maturation and may thus contain a reserve pool of nonheme iron.

scholarly journals The highly sensitive determination of serotonin by using gold nanoparticles (Au NPs) with a localized surface plasmon resonance (LSPR) absorption wavelength in the visible region

RSC Advances ◽  
2020 ◽  
Vol 10 (51) ◽  
pp. 30858-30869
Author(s):  
Phuong Que Tran Do ◽  
Vu Thi Huong ◽  
Nguyen Tran Truc Phuong ◽  
Thi-Hiep Nguyen ◽  
Hanh Kieu Thi Ta ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Visible Region ◽  
Localized Surface Plasmon ◽  
Au Nps ◽  
Highly Sensitive ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Sensitive Determination

The development of improved methods for the synthesis of monodisperse gold nanoparticles (Au NPs) is of high priority because they can be used as substrates for surface-enhanced Raman scattering (SERS) applications relating to biological lipids.

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