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121.
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
122.
Ioannis E. Antoniou Baydyanath Misra 《International Journal of Theoretical Physics》1992,31(1):119-136
We construct a self-adjoint time operator for massless relativistic systems in terms of the generators of the Poincaré group. The Lie algebra generated by the time operator and the generators of the Poincaré group turns out to be an infinitedimensional extension of the Poincaré algebra. The internal time operator generates two new entities, namely the velocity operator and the internal position operator. The transformation properties of the internal time and position operator under Lorentz boosts are different from what one would expect from relativity theory. This difference reflects the fact that the time concept associated with the internal time operator is radically different from the time coordinate of Minkowski space, due to the nonlocality of the time operator. The spectral projections of the time operator allow us to construct incoming subspaces for the wave equation without invoking Huygens' principle, as in two and one spatial dimensions where Huygens' principle does not hold. 相似文献
123.
L K Misra M G Luthra S R Amtey G Elizondo-Riojas S H Swezey L E Todd 《Magnetic resonance imaging》1984,2(1):33-35
Proton spin-lattice relaxation times (T1) of pectoralis major muscles from normal (Line 412) and homozygous dystrophic (Line 413) chicks was measured by FONAR QED 80 at 1.69 MHz. The T1 values of dystrophic muscles (216.8 +/- 17.3 ms) was two-fold higher than those of normal muscles (110.2 +/- 8.1 msec). When these values were compared with the T1 values obtained at high frequencies (20 MHz and 32 MHz), the T1 differentiation between normal and dystrophic muscles was considerably enhanced at 1.69 MHz. Based on these results, we suggest that the high resolution of T1 obtained at low frequency (1.69 MHz) could be effectively used to detect the degenerative processes in muscles by the NMR techniques. 相似文献
124.
Sushil K. Misra Serguei I. Andronenko Prem Chand Keith A. Earle Sergei V. Paschenko Jack H. Freed 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,174(2):2308-269
EPR measurements have been carried out on a single crystal of Mn(2+)-doped NH(4)Cl(0.9)I(0.1) at 170-GHz in the temperature range of 312-4.2K. The spectra have been analyzed (i) to estimate the spin-Hamiltonian parameters; (ii) to study the temperature variation of the zero-field splitting (ZFS) parameter; (iii) to confirm the negative absolute sign of the ZFS parameter unequivocally from the temperature-dependent relative intensities of hyperfine sextets at temperatures below 10K; and (iv) to detect the occurrence of a structural phase transition at 4.35K from the change in the structure of the EPR lines with temperature below 10K. 相似文献
125.
Prabudh R. Misra 《Semigroup Forum》1996,52(1):105-108
In this note we verify a conjecture of Magill [3] about orders of “steplike” functions. These functions turn out to be useful
in producing a finite subsemigroup of S(ℝ) of any given order. 相似文献
126.
A relation between the free energy for dipole relaxation process and that for the association process has been proposed. Using this relation, an equation has been defined for evaluating the association equilibrium constant from the dielectric relaxation measurements. These equations have been applied to study the association of dimethyl sulphoxide and p-tolyl sulphoxide with proton donors (phenol and O-cresol) in an inert solvent carbon-tetra-chloride in the temperature range 298–322K. The calculation of the association equilibrium constant and hence the thermodynamic parameters have shown the wide scope, the proposed relations can be put to in the study of the association process of hydrogen bond complexes. 相似文献
127.
The cell model for diffusion transition has been applied to study first order phase transition and its pressure dependence in polyethylene. The experimental data of Matsuoka have been utilized. The agreement with experimental curves gets progressively better at higher pressure values because of the accompanied crystallisation. 相似文献
128.
129.
X-band data on Gd3+ ions doping some isostructural single crystals of rare-earth trisulphate octahydrate [R2(SO4)3·8H2O] single crystals (RSH) have been obtained at room temperature for the hosts characterized by R = Pr, Nd, Sm, Eu, Yb and Y, and at liquid nitrogen and liquid helium temperatures for the hosts characterized by R = Pr, Sm, Eu and Y. The data are analyzed using a rigorous least-squares fitting procedure in which all resonant line positions obtained for various orientations of the external magnetic field are fitted simultaneously to the same spin Hamiltonian parameters. The intensities of the lines obtained at liquid helium temperatures indicate the absolute sign of the parameter b20 to be negative for R = Pr, Eu and Y, whereas for the Sm host the sign of b20 is found to be positive. While the parameter b20 does not exhibit a clear cut linear dependence upon the host ion radius, the parameter b20 is found to behave approximately linearly as a function of the host-ion radius. On the other hand, the zero-field splitting is found to be a linear function of the host ion radius at all three temperatures—room, liquid nitrogen and liquid helium.A comparison is presented of the systematics of the EPR spectra for the RSH hosts with those for some other isostructural rare-earth hosts. 相似文献
130.
Ashok Misra 《Applied Physics A: Materials Science & Processing》1978,16(2):195-199
Observations of the fracture-induced electromagnetic effect in metals have recently been reported by the author. This paper
presents a physical model for explaining this new effect. The reasoning attributes the observed electromagnetic effect to
dislocationelectron interactions in a metal. The frequency of the emitted radiation has been calculated from Bohr's correspondence
principle and potential on the basis of Hertzian dipole radiation. The proposed physical model predicts emission of electromagnetic
waves at distinct transition stages of elastic-plastic deformations. The paper also presents some of the experimental results,
being obtained by the author, which confirm the practicability of this approach. 相似文献