Chromatic and opto-mechanical dispersion of some characteristic parameters of optical fiber undergoing macrobending

Bending of optical fiber leads to an induced-anisotropy in the index profile that influences many important guiding fiber parameters. An analytical method is described for the measurement of refractive-index-wavelength dispersion in bent optical fibers. Multiple-beam Fizeau fringes technique at transmission is used to analyze the opto-mechanical properties and induced-index anisotropy in a standard single-mode fiber undergoes pure mechanical macrobending. The shift in Fizeau fringes is employed to evaluate the dispersion of the cladding material of the bent fiber. The radial variations in Cauchy’s coefficients and the associated variations of some fiber parameters due to macrobending are carried out. The radial profiles of some material parameters such as oscillation energy, dispersion energy, lattice energy and material dispersion are measured as well. The presented method is capable to achieve quantitative and qualitative measurements, which is not available with other methods. The method has a good index resolution in the order of 10⁻⁴ and spatial resolution of 1.3 μm.     

Studies on heterocyclic enamines: New syntheses of 4H-pyranes,pyranopyrazoles and pyranopyrimidines

The behaviour of several 2-amino-3-cyano-4H-pyran derivatives toward a variety of nucleophilic reagents is reported.     

Reduktion von Cyclohexanonisoxim (α-Ketohexamethylenimin)

Ohne Zusammenfassung     

Spectrofluorimetric determination of guanethidine sulphate,guanfacine hydrochloride,guanoclor sulphate and guanoxan sulphate in tablets and biological fluids,using benzoin

A sensitive and rapid Spectrofluorimetric method for the determination of guanethidine sulphate, guanfacine hydrochloride, guanoclor sulphate and guanoxan sulphate in tablets and spiked human serum and urine samples is described. The method is based on the reaction of monosubstituted guanidino compounds in an aqueous potassium hydroxide solution with benzoin, in the presence of -mercaptoethanol and sodium sulphite. Highly fluorescent derivatives were obtained, with excitation and emission maximum wavelengths around 325 and 430 nm, respectively. In optimal reaction conditions, the linearity ranges were 0.04–0.28 g/ml, with relative standard deviations less than 2%. The method has been successfully applied to the determination of these drugs in tablets. The results are highly correlated with the B.P. method. Chloroform (or for guanoxan dichloromethane) was used to extract the drugs from serum and urine at basic pH, followed by the proposed fluorimetric method. The limit of detection is 0.02 g/ml for the selected drugs.     

On the ternary B 2-phase in the Al-Co-Ga system

Summary Lattice parameter values were determined for the ternary B 2-phase in the Al-Co-Ga system, and it was found that a continuous solid solution exists between -AlCo and -CoGa. Phase boundaries of the ternary phase at 1 100 K were derived from the variation of the lattice parameter with composition.

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Über die ternäre B 2-Phase im System Al-Co-Ga

Zusammenfassung Im Bereich der ternären B 2-Phase im System Al-Co-Ga wurden die Werte des Gitterparameters bestimmt; es stellte sich heraus, daß eine durchgehende feste Lösung zwischen -AlCo und -CoGa besteht. Die Phasengrenzen der ternären Phase bei 1 100 K wurden aus der Änderung des Gitterparameters mit der Zusammensetzung abgeleitet.

     

Über die Darstellung von Verbindungen des Typs Cl3VNR

The reaction of VOCl₃ with sily-substituted amines results in the substitution of oxygen in VOCl₃ and in compounds of type Cl₃V = NR. In this way, we succeeded in isolating the pure compound Cl₃V = NCH₃ (I). The existence of compound (Cl₃VNC₆H₅)_x (II) was proved by direct synthesis from Cl₃VO and ((CH₃)₃Si)₂NC₆H₅, and by the decomposition of the new addition compounds Cl₃VO · 2 OCNC₆H₅ (III) and Cl₃VO · 2 OSNC₆H₅ (IV).     

Determination of the thermodynamic excess functionsG E,H E,andS E of the liquid ternary system AgCl—LiCl—KCl by means of EMF-measurements

By means of EMF-measurements using the formation cell $$graphite/Ag/AgCl(l,x_{AgCl} ) - LiCl(l,x_{LiCl} ) - KCl x_{KCl} /(Cl_2 )graphite$$ the partial molar excessGibbs energies,G _AgCl ^E , of silver chloride in the ternary system AgCl?LiCl?KCl were determined over the whole concentration range at five temperatures between 973 K and 1,123 K. The experimentally determinedG _AgCl ^E -values were fitted using theRedlich-Kister equation. From theRedlich-Kister parameters and their temperature dependence, obtained by the fitting procedure, the integral and partial molar excessGibbs energies, heats of mixing, and excess entropies were calculated. The fitting process permits also the calculation of the thermodynamic excess function of the binary system lithium chloride—potassium chloride.