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21.
The modified wave and scattering operators are shown to be bounded between weighted L
2-spaces for two-body Schrödinger operators with long range potentials. 相似文献
22.
A. Hansen M.H. Jensen K. Sneppen G. Zocchi 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(1):157-161
We present a statistical mechanics treatment of the stability of globular proteins which takes explicitly into account the
coupling between the protein and water degrees of freedom. This allows us to describe both the cold and the warm unfolding,
thus qualitatively reproducing the known thermodynamics of proteins.
Received: 19 March 1998 / Revised and Accepted: 25 May 1998 相似文献
23.
K.J. Devlin has extended Jensen's construction of a model ofZFC andCH without Souslin trees to a model without Kurepa trees either. We modify the construction again to obtain a model with these properties, but in addition, without Kurepa trees inccc-generic extensions. We use a partially defined -sequence, given by a fine structure lemma. We also show that the usual collapse of Mahlo to
2 will give a model without Kurepa trees not only in the model itself, but also inccc-extensions. 相似文献
24.
25.
26.
This paper concerns with three series of experiments about dimethylsulfide gas phase oxidation, carried out at increasing NOx level (< 20 ppb, 1 ppm, 10 ppm) to show the relation between the amounts of nitrogen oxides and the molar yields of sulfur containing products. DMSO, DMSO2, HCHO, HCOOH and SO2 were found as main reaction products. From these experiments and from preceding studies, a sensitive decrease in the quantity of total sulfur products in aerosol phase is underlined. This result derives from the reaction of NOx with CH3S(O)O2 and CH3S(O)OO radicals, which leads to stable intermediates as methylsulphonylperoxynitrate, MSPN, with a characteristic PAN-like structure. 相似文献
27.
Changes in the mass spectra with inlet temperature were used in this work to demonstrate the dependence of keto-enol tautomerism of acetylacetone, 3-methyl acetylacetone and 3-allyl acetylacetone on temperature. The largest dependence of temperature were shown by the ion [M ? 42]+. arising from a McLafferty type rearrangement and by the ion [M ? Me]+ resulting from simple α-cleavage. The ion [M ? 42]+. peak increases with the temperature of the inlet system while the ion [M ? Me]+ peak decreases. By assuming that the ion [M ? 42]+. represents the keto form and that the ion [M ? Me]+ represents the cis-enol form (stabilized by the hydrogen bond) one sees that the direction of the intensity variation of these peaks with temperature is in accord with the expected change of keto-enol tautomerism with temperature. A quantitative correlation on the basis of the above assumptions is also approached. Recording of the mass spectra of these three β-diketones at different energies of the incident electrons enables us to estimate whether or not the particular ions present in the mass spectra result from energetically favourable processes. The variation of the intensities of the peaks with the temperature of the inlet at different electron energies is also discussed. 相似文献
28.
29.
Michael P. Hartshorn Richard G. Jensen A. Grant Waller Graeme J. Wright 《Tetrahedron letters》1987,28(52):6701-6704
Reaction of the 15N-4-nitrodienone (1) with excess nitrogen dioxide in benzene for 16 h gives the 4,5,6-trinitro ketone (2), labelled (15NO2) at C6 but not at C4, and recovered 4-nitrodienone (1) in which extensive loss of 15NO2 has occurred. The mechanistic implications of these and related results are discussed. 相似文献
30.
Li W Nelson DP Jensen MS Hoerrner RS Javadi GJ Cai D Larsen RD 《Organic letters》2003,5(25):4835-4837
Imidazo[1,2-a]pyrimidine can be arylated at the 3-position with aryl bromides in the presence of base and a catalytic amount of palladium. This provides an efficient one-step synthesis of 3-arylimidazo[1,2-a]pyrimidines from the unsubstituted heterocycle. [reaction: see text] 相似文献