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891.
892.
893.
A shell model that describes the formation of molecular complexes around a C60 molecule upon the solid-phase interaction of the powders is considered. From the absorption spectra, it follows that a reacting particle is a fullerene dimer.  相似文献   
894.
Based on the dinuclear system concept, the role of bending vibrations in creation of the angular momentum of primary fission fragments is investigated. For 252Cf spontaneous fission, the angular momenta of the fragments are calculated as a function of the neutron multiplicity and compared with available experimental data. Different cluster compositions of the 252Cf fission modes at the scission point are considered.  相似文献   
895.
We describe a family of graph manifolds that have 2-generated fundamental group but do not admit a Heegaard splitting of genus 2. They are closely related to the examples provided by Boileau and Zieschang if these are considered as (non-proper) graph manifolds.Received: 14 August 2002  相似文献   
896.
Lasing and discharge in mixtures of SF6 with hydrogen and hydrocarbons are investigated. If the chemical reaction is initiated by a self-sustained discharge (a generator with both an inductive and capacitive energy storage can be used), the maximum lasing efficiency is attained at high values of the ratio E/p (where E is the electric field intensity and p is the pressure in the mixture) if shaped electrodes and preionization of the discharge gap are employed. For the first time, the lasing efficiency obtained in a nonchain HF laser is as high as 10% of the energy deposit and 4.5% of the stored energy for a specific radiation energy of ≈140 J/(l atm). At high efficiencies, the emission spectrum of the nonchain HF laser significantly broadens and cascade lasing at P(3-2) → P(2-1) → P(1-0) vibrational transitions for several rotational lines is realized.  相似文献   
897.
The relaxor properties of Fe-doped TlInS2 crystals are investigated. It is shown that Fe-doped TlInS2 compounds exhibit all features inherent in relaxor ferroelectric materials. The temperature range of existence of the microdomain (relaxor) state and the temperature of the transition from this state to a macro-domain state are determined.  相似文献   
898.
899.
Terminal alkynes undergo mild and efficient aminomethylation with aqueous formaldehyde and secondary amines under CuI catalysis. In most cases high to nearly quantitative yields of tertiary propargylamines are obtained in DMSO solution at room temperature. Aromatic, aliphatic and silylated acetylenes as well as alkynols can be used. Primary amines are less reactive and satisfactory yields of secondary propargylamines are obtained only with phenylacetylene.  相似文献   
900.
The kinetics of formation of an anomalous phase from a solution with a small 3He impurity was studied in the temperature range 0.2–0.7 K up to a supersaturation of ~30 mbar. The phase diagram was determined for normal and anomalous growths. It is found that, in the presence of impurities, the formation of a fast-growing state is retarded. This experimental fact indicates that the dissipative processes in fluids have an appreciable effect on the phase formation kinetics. The retardation is, possibly, caused by the direct interaction of an impurity with the crystal surface.  相似文献   
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