Synthesis of the α-monoglyceride oftrans-O-methylmarmesic acid and its modified derivatives—The phosphate and citrate

The α-monoglyceride of trans-O—methylmarmesinic acid and its phosphate and citrate derivatives have been synthesized. The structures of the compounds have been confirmed by IR, UV, PMR and¹³C and³¹P spectroscopies. A. B. Bekturova Institute of Chemical Sciences, Academy of Sciences of the Republic of Kazakhstan, Almaty, fax (3272) 61 57 65. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 452–455, July–August, 1998.     

Periodic modules over general quantum Laurent polynomials

We construct, by induction on the number of variables, periodic finitely generated modules over general quantum Laurent polynomials. Translated fromMatematicheskie Zametki, Vol. 61, No. 1, pp. 10–17, January, 1997. Translated by A. I. Shtern     

Resonance interaction between plasmons and two-phonon states in ZnSe crystals

Raman spectra of doped ZnSe crystals with the carrier densities n = 10¹⁷ to 10¹⁸ cm^?3 have been investigated. It is found that the new intensitive peak appears in the spectra in the case when the plasmon-phonon frequency L₊ falls within the region of two-phonon states. The frequency corresponding to this peak varies with carrier density. This fenomenon is explained by the anharmonic coupling of plasmon and two-phonon excitations.     

Visualizing spin-dependent electronic collisions In ferromagnets

This work demonstrates experimentally and theoretically that the coincident two-electron emission from a ferromagnetic surface, upon the impact of a polarized electron, carries detailed information on the spin-dependent electronic collisions in ferromagnets. The analysis of the calculated and the measured two-electron spectra reveals the potential of the electron-pair emission technique for the study of (a) surface magnetism and (b) spin-dependent electron scattering dynamics in ferromagnets.     

Determination of f(s)/f(d) for 7 TeV pp collisions and measurement of the B0→D-K+ branching fraction

The relative abundance of the three decay modes B(0)→D(-)K(+), B(0)→D(-)π(+), and B(s)(0)→D(s)(-)π(+) produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb(-1). The branching fraction of B(0)→D(-)K(+) is found to be B(B(0)→D(-)K(+)) = (2.01 ± 0.18(stat) ± 0.14(syst)) × 10(-4). The ratio of fragmentation fractions f(s)/f(d) is determined through the relative abundance of B(s)(0)→D(s)(-)π(+) to B(0)→D(-)K(+) and B(0)→D(-)π(+), leading to f(s)/f(d) = 0.253 ± 0.017 ± 0.017 ± 0.020, where the uncertainties are statistical, systematic, and theoretical, respectively.     

<Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> Decay Studies in the OKA Experiment

Recent results from OKA setup concerning form factor studies in K_e3 decay are presented. About 5.25 M events obtained for decays of 17.7 GeV/cK⁺ are selected for the analysis. The linear and quadratic slopes for the decay form factor f₊(t) are measured: λ'₊ = 2.95 ± 0.022 ± 0.018 × 10 ^-2 for the linear slope fit and λ₊ = 2.611 ± 0.035 ± 0.028 × 10 ^-2, λ"₊ = 1.91 ± 0.19 ± 0.14 × 10 ^-3 for the quadratic one. The scalar and tensor contributions are compatible with zero. Several alternative parametrizations are tried: the Pole fit parameter is found to be M _V = 891 ± 3 MeV; the parameter of the dispersive parametrization is measured to be Λ₊ = 2.458 ± 0.018 × 10^-2.