Asymmetric six-vertex model and the classical Ruijsenaars–Schneider system of particles

We discuss the correspondence between models solved by the Bethe ansatz and classical integrable systems of the Calogero type. We illustrate the correspondence by the simplest example of the inhomogeneous asymmetric six-vertex model parameterized by trigonometric (hyperbolic) functions.     

Determination of the NaFaq association constant for the NaF–NaCl–H<Subscript>2</Subscript>O System at 25–75°C by means of potentiometry

Potentiometric measurements are made for the NaF–NaCl–H₂O system at 25, 50, and 75°C using Na⁺- and F^–-sensitive electrodes and a Ag/AgCl reference electrode in both liquid junction and liquid junction free cells. A correction for the liquid junction potential is introduced to the liquid junction cells. The activity coefficients are calculated using the Debya–Hückel equation in the third approximation. The NaF thermodynamic association constants are determined (logK° =–0.375,–0.29, and–0.25) with an error of ±0.1 log units at 25, 50, and 75°C, respectively.     

Characteristic Classes and Hitchin Systems. General Construction

We consider topologically non-trivial Higgs G-bundles over Riemann surfaces ?? _g with marked points and the corresponding Hitchin systems. We show that if G is not simply-connected, then there exists a finite number of different sectors of the Higgs bundles endowed with the Hitchin Hamiltonians. They correspond to different characteristic classes of the underlying bundles defined as elements of ${H^{2}(\Sigma_g, \mathcal{Z}(G))}$ , ( ${\mathcal{Z}(G)}$ is a center of G). We define the conformal version CG of G - an analog of GL(N) for SL(N), and relate the characteristic classes with degrees of CG-bundles. We describe explicitly bundles in the genus one (g =? 1) case. If ??₁ has one marked point and the bundles are trivial then the Hitchin systems coincide with Calogero-Moser (CM) systems. For the nontrivial bundles we call the corresponding systems the modified Calogero-Moser (MCM) systems. Their phase space has the same dimension as the phase space of the CM systems with spin variables, but less number of particles and greater number of spin variables. Starting with these bundles we construct Lax operators, quadratic Hamiltonians, and define the phase spaces and the Poisson structure using dynamical r-matrices. The latter are completion of the classification list of Etingof-Varchenko corresponding to the trivial bundles. To describe the systems we use a special basis in the Lie algebras that generalizes the basis of ??t Hooft matrices for sl(N). We find that the MCM systems contain the standard CM subsystems related to some (unbroken) subalgebras. The configuration space of the CM particles is the moduli space of the stable holomorphic bundles with non-trivial characteristic classes.     

Calogero–Moser systems for simple Lie groups and characteristic classes of bundles

This paper is a continuation of our paper Levin et al. [1]. We consider Modified Calogero–Moser (CM) systems corresponding to the Higgs bundles with an arbitrary characteristic class over elliptic curves. These systems are generalization of the classical Calogero–Moser systems with spin related to simple Lie groups and contain CM subsystems related to some (unbroken) subalgebras. For all algebras we construct a special basis, corresponding to non-trivial characteristic classes, the explicit forms of Lax operators and quadratic Hamiltonians. As by product, we describe the moduli space of stable holomorphic bundles over elliptic curves with arbitrary characteristic classes.     

Interpretation of the vibrational spectra of polycrystalline adenine

The infrared and Raman spectra of the tetramer of the adenine N₉H are calculated and analyzed. The vibrational spectra of polycrystalline adenine are interpreted. It is demonstrated that the method for calculating the vibrational spectra of molecular complexes formed by hydrogen bonds can be used for interpreting the vibrational spectra of polyatomic molecules in the solid state.     

Colloid and Nanosized Catalysts in Organic Synthesis: XXI. Reduction of Nitroarenes Catalyzed by Immobilized Nickel Nanoparticles

Russian Journal of General Chemistry - It has been found that nickel nanoparticles on NaX zeolite, γ-alumina, activated carbon, or magnesium oxide support catalyze the reduction of...     

Irreproducibility of acoustic emission under cyclic irradiation of solids by an infrared laser pulse

Acoustic emission (AE) caused by a stress wave in solid material samples with various thermophysical properties, i.e., copper, aluminum, and glass upon exposure to СO₂ laser pulses is studied. It is found that the general AE picture (the AE signal arrival time, its amplitude, and others) is not reproduced during repeated experiments following one after another, which indicates irreversible local changes occurred in the material structure. The effect of the critical material energy density on the AE pattern during the laser exposure is demonstrated.     

The effect of metallic environment and low temperature on the 253Es α decay rate

In recent publications it has been pointed out that the α decay of transuranic elements in nuclear waste can be considerably speeded up by putting them into metals. The proposed mechanism is based on the effect of electron screening of radioactive nuclei (according to the Debye electron plasma model), which grows enhanced as temperature decreases. To verify the predicted phenomenon, half-lives of ²⁵³Es nuclei implanted in a metallic iron foil were measured at the temperature from 4 K to 50 mK. The results agree with the room-temperature data reported in the literature; no temperature dependence of the half-life was found within the error of ≈2%.     

Synthesis and Reactions of Imidates Containing 1-Adamantyl Group

New unsubstituted and N-substituted 4-(1-adamantyl)benzimidates and (1-adamantyl)acetimidates were prepared from 1-adamantyl-substituted nitriles by a modified Pinner procedure.