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101.
Using the crystal structure, a comprehensive interpretation of the origin of ferroelectricity in the hydrogen bonded triglycine
family of crystals is given. Our detailed analysis showed that the instability of nitrogen double well potential plays a driving
role in the mechanism of the ferroelectric transitions in these crystals. 相似文献
102.
S.C.L. Sharma G.K. Mehta R.K. Choudhury D.M. Nadkarni S.S. Kapoor 《Nuclear Physics A》1981,355(1):13-24
The emission probabilities per fission of α-particles, tritons and protons have been measured in fast neutron induced fission of 235U. The measurements were carried out at neutron energies of 120, 180, 230 and 550 keV. AΔE-E semiconductor detector telescope was used to identify different light charged particles and the fission fragments were detected with an ionization chamber. The three-parameter data corresponding to the pulse heights from the ΔE-E detectors and the ion-chamber were recorded event by event on magnetic tape and were analyzed off-line by computer. No significant variation in the most probable energy () and the standard deviation (σE) of the energy spectra of different light charged particles with incident neutron energy was observed, although was seen to have a slightly higher value beyond En = 230 keV. The yield of α-particles in fission induced by neutrons of En ~ 200 keV was found to be higher by about 20 % than that in thermal neutron induced fission. The yields of tritons and protons were found to increase significantly with neutron energy. 相似文献
103.
Quantum chromodynamics based isovector isoscolar particle mixing arising out of isospin violating quark mass differences has been used to construct a new charge-symmetry breaking Λ-N interaction element. It appears that vector meson exchanges between N and a physical Λ rather than pseudoscalar exchanges provide the largest contribution to explain the binding energy difference between the mirror hyper-nuclei ΛHe4 and ΛH4. Prediction of the model to Λn and Λp scattering lengths have been compared with those obtained from the combined analysis of ΛN scattering and s-shell hyperfragment data. We find satisfactory agreement of our results. 相似文献
104.
We derive an approximate formula for the quark mass in ξ-formalism. Using the QCD-based form of structure function, we analyse
the SLAC-MIT data to estimate the experimentally allowed ranges of quark mass. The possible variation of our results with
QCD cut-off parameter, gluon distribution, hard intrinsic charm component of the proton wavefunction and the higher twist
effects are also discussed. 相似文献
105.
Using an algebraic technique based on the Lie algebra of the group SO(2, 1) the eigenvalues of the triple-well anharmonic
oscillator are calculated for all ranges of the coupling constant. Approximate analytic formulas for the eigenvalues up to
second order are given. The results obtained are compared with those of other authors. 相似文献
106.
C. Basu K. Goswami S. Chaudhuri A. Choudhury 《Journal of Physics and Chemistry of Solids》1981,42(6):527-528
Lattice imperfections were produced in KCl crystals by a thermal process. The heat treated specimen was irradiated with 50 KeV electrons and the corresponding range of electrons in the crystal has been estimated. It was found that the electron range in the crystal depends upon the temperature of heat treatment, being a decreasing function of this temperature up to about 625 K, above which it becomes an increasing function. This anomaly has been explained in terms of dissolution of vacancies through dislocation loops. 相似文献
107.
Assuming the validity of the universal multiplicity hypothesis of quantum chromodynamics, we estimate bounds on quark gluon coupling (αS) and quark mass (m) from the experimental data on charged hadron multiplicities. We obtain 0.3 < αS < 0.5 and m ≈ 100 MeV. Our analysis also suggests the universal quark confinement region to be ≈ O (mπ?1). Comparison with experiment is made for both the hadronic and leptonic induced reactions. 相似文献
108.
Several characteristics of fission accompanied by long range alpha particles (LRA) have been studied in the thermal neutron
induced fission of235U. The kinetic energies of fission fragments and the LRA were measured with a back-to-back ionization chamber and semiconductor
detectors respectively. The kinetic energies of the two fragments and the LRA in LRA fission, along with the energies of pair
fragments in the normal binary fissions, were recorded event by event on a magnetic tape by means of a four-parameter data
acquisition system. The data were analysed to study the dependence of different quantities in LRA fission on the fragment
mass ratio, LRA energy and the total kinetic energy of the fission fragments. It is seen that the most probable energy of
LRA increases significantly for near symmetric mass divisions. The total kinetic energy for all mass ratios in LRA fission
is found to be (2.6±0.7) MeV larger than that in binary fission. The difference in the total kinetic energies in LRA and binary
fissions is seen to be dependent on mass ratio. This result may suggest that the scission configuration in LRA fission is
different for different mass ratios. Correlations between the fission fragment and LRA energies have been studied for several
mass ratios. It is seen that the most probable fragment kinetic energyĒ
k varies nearly linearly with the LRA energyE
a for various mass divisions but the variation of the most probable LRA energyĒ
a with fragment kinetic energyE
k is found to deviate from linearity for several mass ratios. From a least square fit to the variation ofĒ
k withE
a it is found that the slope (dĒ
k/dEa) increases with the increase in mass ratio. The present results are discussed to arrive at a better understanding of the
scission configuration in the fission accompanied by LRA emission. 相似文献
109.
D K Choudhury 《Pramana》1976,7(5):313-315
From the transverse cuts off of the electron positron annihilation in the SPEAR II regime, we obtain positivity domains of
bare quark masses. 相似文献
110.
Laser flash photolysis and an external magnetic field have been used for the study of the interaction of 4-nitroquinoline-1-oxide (4NQO) with some indole derivatives, amino acids, tyrosine and tryptophan, and model proteins, lysozyme and bovine serum albumin. In an aprotic medium, photoinduced electron transfer (PET) from indoles to 4NQO is accompanied by proton transfer from the indole moieties irrespective of the substitution at the N-1 position. For 1,2-dimethylindole, however, proton abstraction is hindered possibly due to steric effects. In a protic medium, obviously proton transfer is possible from the medium and is the dominating reaction following PET. The effect of an external magnetic field is very small for all the systems studied. This is attributed to a competition between geminate proton abstraction by the 4NQO radical anion from the partner radical cation and escape of the 4NQO radical anion to the medium followed by proton transfer. The latter process is more predominant, and the former one, which produces a small population of geminate spin-correlated radical pairs, leads to a minor field effect. Another interesting observation is the affinity of 4NQO toward the tryptophan residues in a protein environment. It is seen that PET takes place preferably from the tryptophan residues rather than from the tyrosine residues. 相似文献