Mesoscopic and microscopic dipole clusters: Structure and phase transitions

Two dimensional (2D) classical system of dipole particles confined by a quadratic potential is studied. For clusters of N < 81 particles ground state configurations and appropriate eigenfrequencies and eigenvectors for the normal modes are found. Monte Carlo and molecular dynamic methods are used to study in detail the order - disorder transition (the "melting" of clusters). In mesoscopic clusters (N < 37) there is a hierarchy of transitions: at lower temperatures an intershell orientational disordering of pairs of shells takes place; at higher temperatures the intershell diffusion sets in and the shell structure disappears. In "macroscopic" clusters (N > 37) an orientational "melting" of only the outer shell is possible. The most stable clusters (having both maximal lowest nonzero eigenfrequencies and maximal temperatures of total melting) are that of completed crystal shells which are concentric groups of nodes of 2D hexagonal lattice with a number of nodes placed in the center of them. The study of different quantities shows that the melting temperature is a nonmonotonic function of the number of particles in the system. The dynamical equilibrium between "solidlike" and "orientationally disordered" forms of clusters is considered.Comment: 12 pages, 16 Postscript figures. Submitted to Phys. Rev.

The clinical signifi cance of urethral sphincter hyperkinesis in the treatment of benign prosta???? c hyperplasia

Introduction. Today there is many highly effective surgical approaches in the treatment of benign prostatic hyperplasia (BPH). New technologies in the treatment of BPH continue to be implemented. Despite this in some patients the results of surgical treatment for short-term and long-term monitoring is unsatisfactory.Purpose of research. Тo improve the results of treatment of patients with benign prostatic hyperplasiaMaterials and methods. The functional state of the urethral sphincter was studied in 123 patients with symptomatic BPH. According to the treatment method, all patients were separated into groups. Group 1 - patients with established standard indications for surgical treatment. After surgery, patients with persistent obstructive urination received therapy with a central muscle relaxant for three months. Group 2 - patients with uncomplicated BPH, having hypertonic urethral sphincter and receiving drug therapy according to the established urodynamic patterns.Results. Our analysis of the efficacy of surgical treatment of patients with BPH demonstrates a significant correlation between negative outcomes of surgery for BPH with increased tone of the external urethral sphincter. So, in 70.1% of cases, symptomatic obstructive Low Urinary Tract Symptoms (LUTS) in BPH were accompanied by increased tone of the urethral sphincter from standard parameters. We believe that these changes were related to the anatomical characteristics of nodular hyperplasia.Conclusions. Exactly this fact, that these patients had urethral sphincter dysfunction in 14.5% of cases made for poor effect of surgical treatment of BPH. Use of muscle relaxants centrally acting drug therapy in these cases, significantly improves the urodynamics of lower urinary tract, which is accompanied by regression of LUTS

Analysis of technical and economic indicators of modern development of food industry in Ukraine

У статті результати аналіз розвитку харчової промис- ловості України. Визначено галузевий склад харчової промисловості. Схарактеризовано перспектив розвитку харчової промисловості України. Сформовано структурно-логічну схему використання результатів аналізу техніко- економічних показників розвитку харчової промисловості.In the article the results of analysis of food industry development in Ukraine are defined. Determined the industry sector of food industry. Described the prospects of food industry development in Ukraine. Formed the structural-logical scheme of using the results of technical-economic indicators analysis of food industry

Bouncing off the walls : the influence of gas-kinetic and van der Waals effects in drop impact

A model is developed for liquid drop impact on a solid surface that captures the thin film gas flow beneath the drop, even when the film’s thickness is below the mean free path in the gas so that gas kinetic effects (GKE) are important. Simulation results agree with experiments, with the impact speed threshold between bouncing and wetting reproduced to within 5 least 50 mapped and provides experimentally verifiable predictions. There are two principal modes of contact leading to wetting and both are associated with a van der Waals driven instability of the film

On automorphisms of a distance-regular graph with intersection array {39, 36, 1; 1, 2, 39}

Possible prime-order automorphisms and their fixed-point subgraphs are found for a hypothetical distance-regular graph with intersection array {39, 36, 1; 1, 2, 39}. It is shownthat graphs with intersection arrays {15, 12, 1; 1, 2, 15}, {35, 32, 1; 1, 2, 35}, and {39, 36, 1; 1, 2, 39} are not vertex-symmetric. © 2016, Pleiades Publishing, Ltd

On automorphisms of a distance-regular graph with intersection array {99, 84, 1; 1, 12, 99}

We find possible orders and fixed point subgraphs of a hypothetical distance-regular graph with intersection array {99, 84, 1; 1, 12, 99}. We show that, for a vertex-symmetric graph Γ with intersection array {99, 84, 1; 1, 12, 99}, its automorphism group is a {2, 3, 5}-group. © 2017, Pleiades Publishing, Ltd

Phase diagram of 2D array of mesoscopic granules

A lattice boson model is used to study ordering phenomena in regular 2D array of superconductive mesoscopic granules, Josephson junctions or pores filled with a superfluid helium. Phase diagram of the system, when quantum fluctuations of both the phase and local superfluid density are essential, is analyzed both analytically and by quantum Monte Carlo technique. For the system of strongly interacting bosons it is found that as the boson density $n_0$ is increased the boundary of ordered superconducting state shifts to {\it lower temperatures} and at $n_0 > 8$ approaches its limiting position corresponding to negligible relative fluctuations of moduli of the order parameter (as in an array of "macroscopic" granules). In the region of weak quantum fluctuations of phases mesoscopic phenomena manifest themselves up to $n_0 \sim 10$. The mean field theory and functional integral $1/n_0$ - expansion results are shown to agree with that of quantum Monte Carlo calculations of the boson Hubbard model and its quasiclassical limit, the quantum XY model.Comment: 7 pages, 5 Postscript figure