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161.
162.
Sunil Singh Chouhan Pooja Soni Gitanjali Pagare S.P. Sanyal M. Rajagopalan 《Physica B: Condensed Matter》2011,406(3):339-344
A theoretical study of structural, electronic, elastic, thermal and mechanical properties of nonmagnetic intermetallics YM (M=Cu, Zn and Ag), which crystallize in CsCl-type structure, is performed using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. The calculations are carried out within the generalized gradient approximation (GGA) for the exchange correlation potential. The calculated ground state properties such as lattice constants, bulk modulus and elastic constants agree well with the experiment. From energy dispersion curves, it is found that these compounds are metallic in nature. The ductility of these intermetallics is determined by calculating the bulk to shear ratio B/GH. The calculated results indicate that YAg is the most ductile amongst the present YM compounds. The results obtained are compared with the available experimental and theoretical results. The mechanical and thermal properties are predicted from the calculated values of elastic constants. 相似文献
163.
The entropic discriminant is a non-negative polynomial associated to a matrix. It arises in contexts ranging from statistics and linear programming to singularity theory and algebraic geometry. It describes the complex branch locus of the polar map of a real hyperplane arrangement, and it vanishes when the equations defining the analytic center of a linear program have a complex double root. We study the geometry of the entropic discriminant, and we express its degree in terms of the characteristic polynomial of the underlying matroid. Singularities of reciprocal linear spaces play a key role. In the corank-one case, the entropic discriminant admits a sum of squares representation derived from the discriminant of a characteristic polynomial of a symmetric matrix. 相似文献
164.
A. Mishra A. Kumar S. Sanyal S. Schramm 《The European Physical Journal A - Hadrons and Nuclei》2009,41(2):205-213
The medium modifications of the energies of kaons and antikaons in isospin asymmetric hyperonic matter are investigated using
a chiral SU(3) model. The isospin-dependent medium effects are important for asymmetric heavy-ion collision experiments, as well as relevant
for the neutron star phenomenology as the bulk matter in the interior of the neutron star is highly isospin asymmetric. The
effects of hyperons on the medium modifications of the kaons and antikaons in the strange hadronic matter are investigated
in the present work and are seen to be appreciable for hadronic matter with large strangeness fractions. The study of the
K -mesons in the asymmetric strange hadronic matter can be especially relevant for the compressed strange baryonic matter which
can result from asymmetric heavy-ion collision experiments in the future accelerator facility FAIR at GSI. 相似文献
165.
In 1989, Kalai stated three conjectures A, B, C of increasing strength concerning face numbers of centrally symmetric convex polytopes. The weakest conjecture, A, became known as the “3
d
-conjecture.” It is well known that the three conjectures hold in dimensions d≤3. We show that in dimension 4 only conjectures A and B are valid, while conjecture C fails. Furthermore, we show that both conjectures B and C fail in all dimensions d≥5. 相似文献
166.
Archana Singh Mahendra Aynyas Sankar P. Sanyal 《Central European Journal of Physics》2009,7(1):102-107
We have predicted the phase transition pressure (P
T
)and high pressure behavior of Zirconium and Niobium carbide (ZrC, NbC). The high pressure structural phase transitions in
ZrC and NbC has been studied by using a two body inter-ionic potential model, which includes the Coulomb screening effect,
due to the semi-metallic nature of these compounds. These transition metal carbides have been found to undergo NaCl (B1) to CsCl (B2)-type structural phase transition, at high pressure like other binary systems. We predict such structural transformation
in ZrC and NbC at a pressure of 98GPa and 85GPa respectively. We have also predicted second order elastic constant and bulk
modulus. The present theoretical work has been compared with the corresponding experimental data and prediction of LAPW and
GGA and LDA theories.
相似文献
167.
We theoretically analyze the ‘cops and robber’ game for the first time in a multidimensional grid. It is shown that in an n-dimensional grid, at least n cops are necessary if one wants to catch the robber for all possible initial configurations. We also present a set of cop strategies for which n cops are provably sufficient to catch the robber. Further, we revisit the game in a two-dimensional grid and provide an independent proof of the fact that the robber can be caught even by a single cop under certain conditions. 相似文献
168.
Carolin Schmitz‐Antoniak Detlef Schmitz Anne Warland Masih Darbandi Soumyajyoti Haldar Sumanta Bhandary Biplab Sanyal Olle Eriksson Heiko Wende 《Annalen der Physik》2018,530(3)
The Verwey transition in Fe3O4 nanoparticles with a mean diameter of 6.3 nm is suppressed after capping the particles with a 3.5 nm thick shell of SiO2. By X‐ray absorption spectroscopy and its associated X‐ray magnetic circular dichroism this suppression can be correlated to localized Fe2+ states and a reduced double exchange visible in different site‐specific magnetization behavior in high magnetic fields. The results are discussed in terms of charge trapping at defects in the Fe3O4/ SiO2 interface and the consequent difficulties in the formation of the common phases of Fe3O4. By comparison to X‐ray absorption spectra of bare Fe3O4 nanoparticles in course of the Verwey transition, particular changes in the spectral shape could be correlated to changes in the number of unoccupied d states for Fe ions at different lattice sites. These findings are supported by density functional theory calculations. 相似文献
169.
We propose a better differential method for the computation of the equation of state of QCD from lattice simulations. In contrast
to the earlier differential method, our technique yields positive pressure for all temperatures including the temperatures
in the transition region. Employing it on temporal lattices of 8, 10 and 12 sites and by extrapolating to zero lattice spacing
we obtained the pressure, energy density, entropy density, specific heat and speed of sound in quenched QCD for 0.9 ≤ T/T
c ≤ 3. At high temperatures comparisons of our results are made with those from the dimensional reduction approach and also
with those from a conformal symmetric theory.
相似文献
170.
R.K. Singh Shankar P. Sanyal J.K. Nayak 《Journal of Physics and Chemistry of Solids》1982,43(1):21-24
An interionic potential model has been proposed to study the static and elastic properties of mixed diatomic crystals. The interaction system of this potential consists of the long-range Coulomb and three-body interaction and the short-range overlap repulsion. This potential has been used to calculate the cohesive energy, phase-transition pressure and volume, third-order elastic constants and pressure derivatives of the effective second-order elastic constants for NaCl-NaBr mixed crystals. These results agree reasonably well with the available experimental results on the host crystals and allow us to draw some meaningful conclusions for the mixed alkali halide crystals. 相似文献