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131.
132.
S. Bhattacharyya 《Il Nuovo Cimento C》1988,11(4):443-446
Summary The very recent measurements on the ratio of cosmic antiproton to proton have contradicted seriously the previous measurements
of the same for low-energy antiprotons. The controversial situation has been described and its implication for the validity
of the postulate about the existence of antigalaxy has been examined. Although a very decisive conclusion cannot yet be made,
a two-component behaviour of the ratio cannot, however, be excluded. Moreover, this two-component proposition seems to have
better prospectsvis-a-vis the high-energy measurements of the ratio. 相似文献
133.
In the light of the equation of motion method a general expression for polarisability calculation has been derived. From this
general expression, different approximation methods can be deduced for different choices of ground state and excitation manifold.
Among these the coupled Hartree-Fock theory is the most extensively used one for polarisability calculations. It has also
been shown that this theory has a simple relationship with random phase approximation. 相似文献
134.
Summary Bjorken predicted in the recent past about the large excess emission of photons in high-energy collisions and this was subsequently
corroborated by some experimentalists as well. Obviously, this phenomenon is just opposite in nature to pro-centauro events
marked by the production of photonless hadrons. In this note we will try to trace the outlines of this confusing and contradictory
situation, probe quantitatively into this excess emission of photons (called progammaisation events) and compare them mainly
with Bjorken's disoriented-chiral-condensate (DCC) model. 相似文献
135.
Kinetic investigations on the reaction between U(IV) and H2O2 have been carried out at different acidities in chloride medium at an ionic strength of 2M. The observed bimolecular rate constant has been found to be dependant on [H+]?1.3. The activation energy of the overall reaction has been found to vary from 13.4 ± 0.7 to 18.0 ± 0.8 kcal/mol in the range of acidity from 0.3 to 1.5M. The results have been explained on the basis of three parallel rate-controlling reactions involving unhydrolyzed species of U(IV) and hydrolyzed species UCl(OH)2+ and UO2+. The values of the rate constants for these three reaction paths have been found to be of the order of 3.95, 5.59 × 103, and 1.49 × 105M?1 min?1, respectively. 相似文献
136.
S. Arai M. Kawai H. Morimoto K. Tanaka H. Seyama M. Soma 《Applied physics. B, Lasers and optics》1988,47(3):243-245
The IRMPD of Si2F6 by a CO2 TEA laser was applied to isotopically selective CVD of silicon. A white film, probably consisting of polymers of SiF2, was deposited on a metal foil during the irradiation of natural Si2F6 with the laser radiation at 951.19 cm–1 and about 1.5 J cm–2. Upon heating, the film became dark brown, evolving SiF4. The30Si content was found to be as high as about 20%. 相似文献
137.
Summary Kinetics of formation of ternary complexes in the reaction of Ni(NTA)(H2O)
2
–
with several amino acids, LH± (glycine, -alanine, -alanine, L-valine and L-phenylalanine) have been studied by a pH indicator method using stopped-flow spectrophotometry. The results conform to 1/kobs = 1/k + [H+]/ kKTL where K is the equilibrium constant for formation of Ni(NTA)(–L)(H2O)2–, and k is the specific rate constant for the subsequent rate-determining ring-closure step leading to Ni(NTA)(=L)2–. For the different amino acids studied, the k values decrease in the sequence: glycine > -alanine > L-phenylalanine > L-valine > -alanine. These k values areca. 1000 times lower than the values for complexation of Ni(NTA)(H2O)
2
–
with NH3 and imidazole and the spread in k values is much less than the pKa values of the amino acids. The relative rates are enthalpy controlled and the S values are highly negative in conformity with ring closure as the rate determining step. 相似文献
138.
D. P. Bhattacharyya 《Zeitschrift für Physik A Hadrons and Nuclei》1970,234(1):17-22
The vertical momentum spectrum of cosmic-ray muons has been determined by a counter controlled neon-hodoscope in the spectral region (0.2–3) Bev/c at geomagnetic latitude 12 °N. The observed spectrum agrees satisfactorily with the calculated spectrum of Olbert for muon momentum above 1.8 Bev/c. Below about 1.8 Bev/c, the measured spectrum exceeds slightly the theoretical spectrum of Olbert, calculated for the same geomagnetic latitude. The measured spectrum agrees with the experimental spectrum of Allkofer at 9 °N, but is somewhat below the spectrum obtained by Hayman in the low momentum region at 57.5 °N. This shows that there exists a latitude dependence of the low momentum muon spectrum. The estimated integral intensity of muon of momentum ≧320 Mev/c is found to be 7.3×10?3 cm?2 sec?1 str?1 which agrees with the value of other investigators1–9. 相似文献
139.
Reduction and reductive alkylation of the tricyclic α,β-unsaturated ketones 9–12 afforded the saturated ketones 13–21 in high yields. 相似文献
140.
Adenine has been used as the template for the directed synthesis of 5-substituted imidazoles. A Novel intermediate involved in the cyclic operation has been characterised. 相似文献