Inhomogeneity of Structural and Dynamical Characteristics of Dusty Plasma in a Gas Discharge

Journal of Experimental and Theoretical Physics - Dusty plasma crystals are commonly considered as spatially homogeneous structures with equal values of their structural and thermodynamic...     

A Silver-Based Electrocontact Material Dispersion-Strengthened with Zinc,Tin, and Titanium Oxides

Technical Physics - A new silver-based electrocontact material dispersion-strengthened with nanopowders of zinc, tin, and titanium oxides has been obtained. The microstructure and elemental...     

Sparse Multicategory Generalized Distance Weighted Discrimination in Ultra-High Dimensions

Distance weighted discrimination (DWD) is an appealing classification method that is capable of overcoming data piling problems in high-dimensional settings. Especially when various sparsity structures are assumed in these settings, variable selection in multicategory classification poses great challenges. In this paper, we propose a multicategory generalized DWD (MgDWD) method that maintains intrinsic variable group structures during selection using a sparse group lasso penalty. Theoretically, we derive minimizer uniqueness for the penalized MgDWD loss function and consistency properties for the proposed classifier. We further develop an efficient algorithm based on the proximal operator to solve the optimization problem. The performance of MgDWD is evaluated using finite sample simulations and miRNA data from an HIV study.     

Strategies for Probing P-Parity Violation in Nuclear Collisions at the NICA Accelerator Facility

Physics of Particles and Nuclei Letters - Possible approaches to experimentally detecting P-parity violation in polarized proton or deuteron interactions with an unpolarized target are discussed....     

Approximate solutions of the Liouville equation. III. Variational principles and projection operators

Aspects of stationary variational principles for the Laplace-transformed Liouville equation are discussed. Projection techniques are used to derive new stationary principles applicable to the space orthogonal to the space spanned by functions occurring in the conservation laws. As a result, any trial function automatically leads to results satisfying the conservation laws. The procedure is also applied to the parity-even and parity-odd distributions which obey equations governed by the square of the Liouville operator. The technique is extended to eliminate the one-body additive contribution to the solution exactly. Finally, the ideas of the moment method, which leads to the continued-fraction representation of autocorrelation functions, are applied to variational principles. We find continued-fraction variational principles such that a zero trial function yields the usual representation. However, a trial function representing noninteracting particles contains the results of the moment method and in addition yields the exact analytic behavior for free particles.Work supported by a grant from the National Science Foundation.     

Physics and the explanation of life

It is proposed to consider present-day physics as dealing with a special situation, the situation in which the phenomena of life and consciousness play no role. It is pointed out that physical theory has often dealt, in the past, with similarly special situations. Planetary theory neglects all but gravitational forces, macroscopic physics neglects fluctuations due to the atomic structure of matter, nuclear physics disregards weak and gravitational interactions. In some of these cases, physicists were well aware of dealing with special situations, or limiting cases as they are called in the article; in other cases, they were not. It is pointed out that, even if it were true that present-day physics accurately describes the motion of the physical constituents of living bodies, it would not give the whole story. Arguments are adduced, however, to show that the laws of physics, applicable for inanimate matter, will have to be modified when dealing with the more general situation in which life and consciousness play significant roles.The present article is a somewhat revised version of the address presented by the writer at the 1969 AAAS meeting in Boston, Mass.     

Generalized characters of the symmetric group

Normalized irreducible characters of the symmetric group S(n) can be understood as zonal spherical functions of the Gelfand pair (S(n)×S(n),diagS(n)). They form an orthogonal basis in the space of the functions on the group S(n) invariant with respect to conjugations by S(n). In this paper we consider a different Gelfand pair connected with the symmetric group, that is an “unbalanced” Gelfand pair (S(n)×S(n−1),diagS(n−1)). Zonal spherical functions of this Gelfand pair form an orthogonal basis in a larger space of functions on S(n), namely in the space of functions invariant with respect to conjugations by S(n−1). We refer to these zonal spherical functions as normalized generalized characters of S(n). The main discovery of the present paper is that these generalized characters can be computed on the same level as the irreducible characters of the symmetric group. The paper gives a Murnaghan-Nakayama type rule, a Frobenius type formula, and an analogue of the determinantal formula for the generalized characters of S(n).     

Phase diagram and equations of state of BaSO4

Abstract

The phase diagram and equations of state of BaSO₄, were determined up to 29 GPa and 1000 K in a resistance-heating type diamond anvil cell. At room temperature, barite is the stable form of BaSO₄ which undergoes a reversible phase transition at 10 GPa. The high-pressure form is tentatively determined to be triclinic. At high temperature, a similar phase transition takes place in BaSO₄, but at a pressure higher than that at room temperature. Our results indicate that the phase boundary of the two polymorphs in BasO₄ has a positive slope (dT/dP) of 90 K/GPa. The equations of state for both barite and its high-pressure phase are reported.     

Application of Nutations to Studying the Exchange Processes by the Method of Nuclear Quadrupole Resonance Spectroscopy

A method of direct determining the discontinuous rotational reorientation angles from NQR exchange spectra based on recording of two-dimensional nutations of magnetization after the mixing period is suggested. The possible modification of the Jeener pulse sequence with independently varying duration of pulses for obtaining a 2D exchange nutation spectrum is described. Shapes of singularities in the 2D nutation spectrum of CCl₂- and CCl₃-group reorientations, which depend on the angle _S between C–Cl bonds and on the asymmetry parameter for nonequivalent positions of nuclei participating in the exchange are examined. The 2D exchange NQR nutation spectra of ³⁵Cl in powders prepared from C₂Cl₄ and C₂Cl₆ molecular crystals are modeled. The advantages and capabilities of the method are discussed.