Union curvature of a vector field in a subspace

The differential equations of union curves on a hypersurfaceV _n immersed in a RiemannianV _n+1 have been obtained by Springer [1]. These results were generalized later for a subspace in a Riemannian space by Mishra [2]. The author [3] has defined the union curvature of a vector field with respect to a curve on a hypersurfaceV _n of a RiemannianV _n+1. The purpose of this paper is to consider union curvature of a vector field with respect to a curve in a subspaceV _n of a RiemannianV _m. The author is indebted to the referee for helpful suggestions.     

Structure and energy studies of Β-diketonates. 5. structure of the Y(DPM)2 radical from gas-phase electron diffraction data

The overheated vapor of yttrium tris-dipivaloyl methanate was studied by combined electron diffractometry and mass spectrometry. It was established that at 760 K the vapor of Y(DPM)₃ contains the Y(DPM)₂ molecular form. The r_a, r_g, and r_a parameters of Y(DPM)₂ were determined, and it was found that the chelate system of Y(DPM)₂ has a planar structure. Possible reasons for differences in the intemuclear distances of the Y(DPM)₂ and Y(DPM)₃ molecular forms are discussed. Translated fromZhurnal Strukturnoi Khimii, Vol. 38, No. 3, pp. 480–488, May–June, 1997.     

Synthese einiger Oxazolin-5-one

Ohne Zusammenfassung     

Strategies for molecular designing of novel low-band-gap electrically conducting polymers

Molecular designing of low-band-gap electrically conducting polymers continues to be a major challenge of the field of electrically conducting polymers. Such polymers are expected to show not only good intrinsic conductivity but also possibly a good transparency in the visible spectrum for their use as infrared sensors/detectors. Low-band-gap polymers can also be of great interest as new polymeric materials for nonlinear optics. Various routes presently followed to achieve this designing with special reference to the donor-acceptor polymers and important results obtained with this route are briefly reviewed.     

Lonijaposides, novel cerebrosides from Lonicera japonica

Six novel cerebrosides, lonijaposides A₁-A₄, B₁ and B₂ (1-6) have been isolated from the flowers of Lonicera japonica. Their structures were established on the basis of 1D, 2D (DEPT, HMQC, HMBC and COSY) NMR, ESI-QTOF-MS/MS and chemical evidence.     

Spectroscopy of the Kondo problem in a box

Motivated by experiments on double quantum dots, we study the problem of a single magnetic impurity confined in a finite metallic host. We prove an exact theorem for the ground state spin, and use analytic and numerical arguments to map out the spin structure of the excitation spectrum of the many-body Kondo-correlated state, throughout the weak to strong coupling crossover. These excitations can be probed in a simple tunneling-spectroscopy transport experiment; for that situation we solve rate equations for the conductance.