Sesquiterpene lactones from Artemisia caucasica

Conclusions 1. Two sesquiterpene lactones have been isolated from the epigeal green part ofArtemisia caucasica Willd.: one with the composition C₁₅H₁₈O₅·H₂O, which has been called grossmisin, and one with the composition C₁₅H₁₈O₅, identified as rutifolin. Structure (I) has been proposed for grossmisin.2. The structure of anhydroaustricin has been reviewed. Structure (II) is proposed for it.Pyatigorsk Pharmaceutical Institute. All-Union Scientific-Research Institute for Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 741–744, November–December, 1971.     

Modeling the focusing microlenses of an auger analyzer equipped with a CMA

A method for and the results from modeling a film probe-shaping lens satisfying stringent mass-dimensional requirements and intended for use as part of an Auger analyzer equipped with a CMA are presented. The optimized electron-optical characteristics of the lens (the distribution of effective potential and the geometry of the electrode space) are obtained.     

Luminescence Excitation Spectroscopy of InAs/InGaAs/GaAs Quantum-Dot Arrays in the Temperature Range between 20 and 300 K

Optics and Spectroscopy - Evolution of photoluminescence (PL) and PL excitation spectra in structures containing InAs/InGaAs/GaAs quantum-dot (QD) arrays is investigated in detail as a function of...     

Mass-spectrometric study of the sesquiterpene lactone germanin-A and its derivatives

Summary The mass spectra of the sesquiterpene lactone germanin-A and 11 of its derivatives and deuterium analogs have been studied. A scheme has been put forward for the decomposition of germanin-A under the action of electron impact. It has been established that the elimination of a molecule of acid from position 8 in the dissociative ionization of germanin-A and of tetrahydrogermanin-A involves the hydrogen atom of the carboxy group present in position 10 of the sesquiterpene ring. On this basis, a suggested conformation of the germanin-A molecule has been put forward.M. V. Lomonosov Moscow State University. All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 337–345, May–June, 1978.     

Model of a spatially inhomogeneous one-dimensional active medium

We investigate the dynamics of one-dimensional discrete models of a one-component active medium analytically. The models represent spatially inhomogeneous diffusively concatenated systems of one-dimensional piecewise-continuous maps. The discontinuities (the defects) are interpreted as the differences in the parameters of the maps constituting the model. Two classes of defects are considered: spatially periodic defects and localized defects. The area of regular dynamics in the space of the parameters is estimated analytically. For the model with a periodic inhomogeneity, an exact analytic partition into domains with regular and with chaotic types of behavior is found. Numerical results are obtained for the model with a single defect. The possibility of the occurrence of each behavior type for the system as a whole is investigated. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 124, No. 3, pp. 506–519, September, 2000.