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81.
Condensation of carboxylic acids and alcohols to give esters was accomplished with selectivity under photolytic conditions in 66-99% yields by use of CCl4 or BrCCl3 at room temperature. 相似文献
82.
83.
W. Ahner P. Baltes Ch. Bormann D. Brill R. Brockmann M. Cieślak E. Grosse W. Henning P. Koczoń B. Kohlmeyer W. Konrad D. Miśkowiec Ch. Müntz H. Oeschler H. Pöppl W. Prokopowicz F. Pühlhofer R. Renfordt A. Sandoval S. Sartorius R. Schicker E. Schwab P. Senger Y. Shin J. Stein K. Stiebing R. Stock H. Ströbele K. Völkel A. Wagner W. Waluś 《Zeitschrift für Physik A Hadrons and Nuclei》1991,341(1):123-124
Subthreshold kaon production in197
Au+197
Au collisions at 1.0 GeV/u has been investigated with the Kaon Spectrometer at SIS. At
lab
=44±4 we found aK
+/p ratio of>3 · 10–4 for the momentum range 650 MeV/c to 1150 MeV/c.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday 相似文献
84.
The cis-influence observed in chlorine NQR data of X, Y affecting the Pt-Cl bonds in compounds of type trans-[PtCl2XY] is interpreted. -bonding differences in Pt-Cl bonds are suggested to account for the trends in NQR frequencies. Pt-Cl -bonding is negligibly small for both d
(Pt)–p
(Cl) and p
–p
(Cl) interactions. 相似文献
85.
Moti Gitik 《Archive for Mathematical Logic》2008,47(1):53-64
Answering a question of Pereira we show that it is possible to have a model violating the Singular Cardinal Hypothesis without
a tree-like continuous scale.
We are grateful to Luis Pereira for asking an interesting question and his comments on the paper. We would like to thank to
the referee of the paper for his comments and corrections. 相似文献
86.
In [5], XI, S. Shelah formulated a condition on forcing notion ( -condition) which implies that the forcing it satisfies does
not add reals. It was proved that, under some additional demands, this condition is preserved by revised countable support
iterations. We are going to show that these demands can be weakened. A few examples of simple forcing notions that can iterate
while preserving the-condition, and hence without adding reals, are presented. 相似文献
87.
88.
89.
Solid alkaline metal hydroxides displayed high catalytic activity and full selectivity in the aerobic oxidation of benzylic
alcohols in a non-polar medium. The activity of the solid bases, in decreasing order of reactivity, was KOH > NaOH ≫ LiOH.
Water, which is the only by-product of the reaction, plays a crucial role in KOH deactivation by converting the crystal phase
of KOH to KOH · H2O, as confirmed by XRD measurements. 相似文献
90.
In exploring the effects of solvent density on the mode and the degree of solvation of the bare and passivated 38-atom gold particle in supercritical ethane, we have extended the molecular dynamics simulations of the system, reported previously,(34) to cover a range of isotherms in the T > T(c) regime, where T(c) is the critical temperature of the solvent. Consonant with our previous observations, the modes of solvation of the bare and the passivated particle, deduced from the radial distribution of the solvent about the metal core center of mass, are found to be vastly different from each other at all solvent densities: while the molecules solvating the bare particle form a well-defined, two-region layer around it, those solvating the passivated particle are loosely dispersed in the passivating layer. For the bare particle, the degree of solvation (vartheta) as a function of solvent density passes through a maximum occurring in the close vicinity of the critical point, consistent with our previous results and in agreement with Debenedetti's theoretical analysis,(22,23) which predicts a solvation enhancement effect in the critical region for systems where the unlike solvent/solute interaction is much stronger than the solvent/solvent interaction. Taking the degree of solvation (vartheta) as a measure of solvent quality, we have investigated how the solvent quality would vary along the solvent-density isotherms. In the solvent-density regime rho > rho(c), the solvent quality is found to be a decreasing function of the density as a result of progressive dominance of the excluded volume effect over the attractive particle/solvent interactions. The particle/solvent affinity is greatly reduced in the presence of the passivating layer, resulting in considerable shrinkage of the good-solvent-quality domain in the supercritical regime. The solvent environment and the presence of the passivating chains produce significant disorder in the equilibrium structure assumed by the nanoparticle core. 相似文献