A Novel Dimeric Eremophilane from Ligularia virgaurea spp. oligocephala

A novel dimeric eremophilane, ligulolide B, was isolated from the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure was elucidated by various spectroscopic methods including intensive 2D NMR techniques （^1H-^1H COSY, gHMQC, gHMBC and ^1H-^1H NOESY） and HR-ESI-MS.     

Molecular-orbital X-rays from 1 GeV 208Pb + 208Pb and 209Bi + 209Bi collisions

We have measured the spectra of continuum X-rays above the characteristic K lines for 4.5 to 4.8 MeV/N ²⁰⁸₈₂Pb → ²⁰⁸₈₂Pb, Pb → Bi, Bi → Pb and Bi → Bi collisions. Above ≈400 keV X-ray energy the spectral shape and intensity agree roughly with calculations of Kirsch et al. for the 1sσ molecular-orbital (MO) X-ray spectrum from Pb-Pb. Deviations from the theory below ≈400 keV suggest transitions to other MO's.     

一类齐次对称多项式上的切比雪夫不等式

本文借助于控制不等式及数学归纳法，将著名的切比雪夫不等式推广到m次一般齐次对称多项式上(如文中定理及引理7)，并将此结果用于对称平均等．旨在展示证明解析不等式的一些有效的方法和技巧，同时为数学研究特别是高维几何研究提供一些新的有趣而有用的解析不等式．     

PbK-shell ionization probability in high-energy Xe+Pb collisions

Probabilities for PbK-shell ionization in 5.9-, 7.2-, and 8.5-MeV/a.m.u. Xe+Pb collisions for impact parameters between 10 and 60 fm are reported. The measured probabilities are compared with theories of 1sσ-vacancy production.     

Quinone—cyanide reactions: their use for the determination of quinones and cyanide

Both quinones and cyanide can be determined in the μg—ng ml^-1 range by measuring the fluorescence of the addition products produced. The yield is low (except for the 2-sulfonic acid of 1,4-naphthoquinone) in aqueous solution and 1:1 DMSO:water is the recommended medium for determinations of quinones. The 2-sulfonic acid of 1,4-naphthoquinone permits the determination of trace amounts of cyanide in aqueous solution; there are few interferences.