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991.
992.
首次用脉冲辐解时间分辨方法研究了etoposide(VP16)在水溶液中与N~3^.,(SCN)~2^.^-和e~a~q^-之间发生的单电子氧化还原反应,测定了VP16的阴离子自由基、脱质子中性自由基的特征吸收谱;测得VP16与e~a~q^-,N~3^.,(SCN)~2^.^-的绝对反应速率常数分别为2.7×10^9,3.2×10^9和2.5×10^8dm^3.mol^-^1.s^-^1。研究表明,水溶液中的VP16可为248nm激光光电离,光电离的瞬态产物为阳离子自由基及脱质子中性自由基,并且测定了其酸碱电离的pK值。测得SO~4^.^-自由基单电子氧化VP16的反应速率常数为2.8×10^9dm^3.mol^-^1.s^-^1。 相似文献
993.
Liu Yuyan Liu Hongping Guo Yuanqing Liu Xiaoyong Lin Jieli Huang Guangming Gao Hui Li Jinrui 《中国科学B辑(英文版)》2000,43(2):121-128
LMR spectra for v=1←0 transitions of14N16O in X2II1/2, 3/2 states were observed at 5.6 μm and 5.4 μm of CO laser. Introducing the advanced isotopic molecular constant scaling function
to Hund’s case (a) diatomic structure model, these spectra were analyzed and fitted together with all reliable previous spectral
data of14N16O as well as14N17O and14N18O. A full set of precise molecular parameters and their vibrational dependencies have been determined with much higher precision
(1–2 orders for most parameters). Many of them have been obtained for the first time. Using isotopic scaling function, the
molecular constants of14N17O and14N18O were deduced. 相似文献
994.
Shuang Xi MEI Zhi NA Xue Mei NIU Chao Ming LI Zhong Wen LIN Han Dong SUN* Laboratory of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming 《中国化学快报》2000,11(12)
In our previous paper1, we reported a novel sesquiterpenoid from the EtOAc part of Coleus xanthanthus. The continuous work for the investigation of the petroleum part of C. xanthanthus led to the isolation of two new abietane diterpenoids which were identified as 11-acetoxy-coleon U(1) and 11,16-diacetoxy-coleon U(2) by spectral methods. Figure 1 The structures of 1 and 2 1 2 R= H OAcCompound 1 was obtained as pale yellow cubic crystals, mp:190.5-1920C; [(]+ 20.50 (c=0.875, CHCl3). Its… 相似文献
995.
996.
A phase diagram of the V2O5–Fe8V10W16O85 system were carried out using XRD and DTA methods. In addition, an indexing of Fe8V10W16O85 powder diffraction pattern was made and its basic crystallographic parameters were determined. Finally, the phase was studied
using IR spectroscopy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
997.
Reuben Rabi 《manuscripta mathematica》2001,105(4):425-469
We construct certain extensions of Hodge structures using points on algebraic curves and study them. We also introduce and
use a related function theory which forms a genus g > 0 version of that of classical hyperlogarithms.
Received: 9 May 2000 / Revised version: 8 December 2000 相似文献
998.
Unstable operations in a generalized cohomology theory E give rise to a functor from the category of algebras over E? to itself which is a colimit of representable functors and a comonoid with respect to composition of such functors. In this paper I set up a framework for studying the algebra of such functors, which I call formal plethories, in the case where E? is a Prüfer ring. I show that the “logarithmic” functors of primitives and indecomposables give linear approximations of formal plethories by bimonoids in the 2-monoidal category of bimodules over a ring. 相似文献
999.
We investigate frequently hypercyclic and chaotic linear operators from a measure-theoretic point of view. Among other things, we show that any frequently hypercyclic operator T acting on a reflexive Banach space admits an invariant probability measure with full support, which may be required to vanish on the set of all periodic vectors for T ; that there exist frequently hypercyclic operators on the sequence space c0 admitting no ergodic measure with full support; and that if an operator admits an ergodic measure with full support, then it has a comeager set of distributionally irregular vectors. We also give some necessary and sufficient conditions (which are satisfied by all the known chaotic operators) for an operator T to admit an invariant measure supported on the set of its hypercyclic vectors and belonging to the closed convex hull of its periodic measures. Finally, we give a Baire category proof of the fact that any operator with a perfectly spanning set of unimodular eigenvectors admits an ergodic measure with full support. 相似文献
1000.
To every group of I-type, we associate a finite quotient group that plays the role that Coxeter groups play for Artin–Tits groups. Since groups of I-type are examples of Garside groups, this answers a question of D. Bessis in the particular case of groups of I-type. Groups of I-type are related to finite set-theoretical solutions of the Yang–Baxter equation. So, our result provides a new tool to attack the problem of the classification of finite set-theoretical solutions of the Yang–Baxter equation. 相似文献