S 66 Skripov, V. P. Size effect on melting of small particles [Text] / V. P. Skripov, V. P. Koverda, V. N. Skokov // Physica Status Solidi (A). - 1981. - V. 66, N 1. - P109-118 Рубрики: ФИЗИКА Кл.слова (ненормированные): ЭФФЕКТ РАЗМЕРНЫЙ -- РАЗМЕРНЫ ЭФФЕКТ -- ПЛАВЛЕНИЕ -- частицы малые -- МАЛЕНЬКИЕ ЧАСТИЦЫ (ФИЗИКА) -- ТЕПЛОФИЗИКА |
B 16 Baidakov, V. G. Attainable Superheat of Argon-Helium, Argon-Neon Solutions [Text] / V. G. Baidakov, A. M. Kaverin, V. N. Andbaeva // Journal of Physical Chemistry B. - 2008. - Vol. 112, № 41. - P12973-12975 Рубрики: ФИЗИКА Кл.слова (ненормированные): ARGON Аннотация: The method of lifetime measurement has been used to investigate the kinetics of spontaneous boiling-up of superheated argonhelium and argon?neon solutions. Experiments were made at a pressure of p = 1.5 MPa and concentrations up to 0.33 mol% in the range of nucleation rates from 104 to 108 s1 m3. The homogeneous nucleation regime has been distinguished. With good agreement between experimental data and homogeneous nucleation theory in temperature and concentration dependences of the nucleation rate, a systematic underestimation by 0.250.34 K has been revealed in superheat temperatures over the saturated line attained by experiment as compared with theoretical values calculated in a macroscopic approximation. The revealed disagreement between theory and experiment is connected with the dependence of the properties of new-phase nuclei on their size. \\EXPERT2\NBO\Journal of Physical Chemistry B\2008, v.112, p.12973.pdf |
B 16 Baidakov, V. G. Nucleation in a superheated nitrogen-helium solution [] / V. G. Baidakov // Chemical Physics Letters. - 2008. - Vol. 462, № 4-6. - С. 201-204 Рубрики: ФИЗИКА Кл.слова (ненормированные): HELIUM Аннотация: The method of lifetime measurement has been used to investigate the nucleation of the vapor phase in a superheated liquid nitrogen–helium solution. Temperature dependences of the mean lifetime of a metastable solution have been obtained in experiments at pressures p = 0.5, 1.0 MPa and several values of the mixture concentration. The nucleation rate J has been calculated. It varied in experiments from 104 tо 108 s?1 m?3. The results of experiments are compared with homogeneous nucleation theory. The paper deals with the size effect on the surface tension of a nucleus and the work of its formation. \\\\Expert2\\nbo\\Chemical Physics Letters\\2008, v. 462, p.201.pdf |
C 74 Computer simulation of nucleation in a gas-saturated liquid [Electronic resource] / S. P. Protsenko, V. G. Baidakov, A. S. Teterin, E. R. Zhdanov // Journal of Chemical Physics. - 2007. - Vol. 126, № 9. - P094502/1-094502/14 Рубрики: ФИЗИКА Кл.слова (ненормированные): LIQUID Аннотация: Molecular dynamics methods have been used to investigate the kinetics of the liquid-gas phase transition in a two-component Lennard-Jones system at negative pressures and elastic stretches of the liquid to values close to spinodal ones. The molecular dynamics system consists of 2048 interacting particles with parameters of the Lennard-Jones potential for argon and neon. Density dependences of pressure and internal energy have been calculated for stable and metastable states of the mixture at a temperature T*?0.7±0.01 and three values of the concentration. The location of mechanical and the diffusion spinodals has been determined. It has been established that a gas-saturated mixture retains its stability against finite variations of state variables up to stretches close to the values near the diffusion spinodal. The statistic laws of the process of destruction of the metastable state have been investigated. The lifetimes of the metastable phase have been determined. It is shown that owing to the small height of the potential barrier that separates the microheterogeneous from the homogeneous state a system of finite size has a possibility to make the reverse transition from the microheterogeneous into the homogeneous state. The lifetimes of the system in the microheterogeneous state, as well as the expectation times of the occurrence of a critical nucleus, are described by Poissonian distributions. \\\\Expert2\\NBO\\Journal of Chemical Physics\\2007, v.126, p.094502, S.P.Protsenko.pdf |
B 16 Baidakov, V. G. Extended version of the Van der Waals capillarity theory [Electronic resource] / V. G. Baidakov, G. Sh. Boltachev // Journal of Chemical Physics. - 2004. - Vol. 121, № 17. - P8594-8601 Рубрики: ФИЗИКА Кл.слова (ненормированные): VAN-DER-WAALS CHAIN-MOLECULE FLUID Аннотация: An extended version of the van der Waals capillarity theory describing the liguid-vapor interface in the temperature range from the triple to the critical point is suggested. A model functional of thermodynamic potential for a two-phase Lennard-Jones system taking into account the effect of the highest degree terms of gradient expansion has been constructed. The identity of the thermodynamic and the mechanical definition of Tolman’s length has been proved in the framework of the adopted form of functional. The properties of nuclei of the liquid and the vapor phase are described. The paper determines: the work of formation of a nucleus, density profiles, size dependences of the surface tension, and the parameter ? in the Gibbs-Tolman-Koenig-Buff equation.© 2004 American Institute of Physics. \\\\Expert2\\NBO\\Journal of Chemical Physics\\2004, v.121, p.8594, V. G. Baidakov.pdf |
G 15 Galashev, A. E. Computer investigation of the structure of Si73 clusters surrounded by hydrogen [Текст] / A. E. Galashev, I. A. Izmodenov // Glass Physics and Chemistry. - 2008. - Vol. 34, № 2. - С. 173-181 Рубрики: ФИЗИКА Кл.слова (ненормированные): HYDROGEN Аннотация: The stabilization of the structure of Si73 clusters that are surrounded by 60 hydrogen atoms and subjected to seventeenfold stepwise heating from 35 to 1560 K (in steps of ?90 K) is investigated using the molecular dynamics method. The analysis is performed for clusters of three types, i.e., a particle assembled from an icosahedron and a fullerene, a nanocrystal, and a particle with a random atomic packing. In all cases, an increase in the temperature in the course of heating is accompanied by evaporation of a Si atom from the clusters and an increase in the size of silicon particles. The temperature of detachment of Si atoms from clusters is lowest for the cluster with a random atomic packing and highest for the nanocrystal. The nanoassembled particle has the most stable number (close to four) of Si-Si bonds per atom over the entire temperature range 35 ? T ? 1560 K. For each type of Si73 clusters, the mean length of the Si-Si bond decreases with an increase in the temperature. According to the radial distribution functions, the Si73 clusters have different structures even at the temperature T = 1560 K. The distributions of bond angles reflect the presence of fourfold symmetry elements in the nanoassembled cluster and the nanocrystal. The relative depth of “penetration” of hydrogen atoms into the cluster is largest for the nanocrystal and smallest for the nanoassembled nanoparticle. The largest number of hydrogen atoms is “adsorbed” on the particle with a random atomic packing. \\\\Expert2\\NBO\\Glass Physics and Chemistry\\2008, v. 34, N 2, p.173.pdf |
N 89 Novruzov, A. N. Computer study of the absorption of ethane by aqueous ultradispersed medium: IR spectra [Текст] / A. N. Novruzov, O. R. Rakhmanova, A. E. Galashev // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2008. - Vol. 70, № 1. - С. 55-63 Рубрики: ФИЗИКА Кл.слова (ненормированные): IR SPECTRA Аннотация: Absorption of ethane molecules by water clusters containing 10–20 molecules is studied by the molecular dynamics method. The (H2O) n (I), C2H6(H2O) n (II), and (C2H6)2(H2O) n (III) cluster systems are composed on the basis of specific statistical weights. Spectral characteristics of system and single clusters are determined in the frequency range of 0 меньше либо равно омега меньше либо равно 1000 cm в степени -1. In this frequency range, both real and imaginary parts of dielectric permittivity decrease monotonically after the absorption of C2H6 molecules by an aqueous ultradispersed system. Integral coefficient of IR absorption increases, while average (over frequency) reflection coefficient decreases after the absorption of ethane molecules. The intensity of IR scattering by the systems of clusters containing C2H6 molecules lowers. Maximal values of radiation power for water clusters with various sizes are balanced with the capture of ethane molecules by the clusters, whereas oscillations in the size dependence of the density of electrons that are active with respect to IR radiation decrease. \\\\Expert2\\NBO\\Colloid Journal\\2008, V.70, N 1, 55.pdf |
G 15 Galashev, A. E. Computer investigation of physical properties of water clusters. 1. Stability [Текст] / A. E. Galashev, O. R. Rakhmanova // Journal of Structural Chemistry. - 2005. - Vol. 46, № 4. - С. 626-632 Рубрики: ФИЗИКА Кл.слова (ненормированные): CLUSTERS -- COMPRESSIBILITY -- DIELECTRIC CONSTANT -- DIPOLE MOMENT -- HEAT CAPACITY Аннотация: The method of molecular dynamics is applied to investigate the stability of water clusters containing up to 90 molecules. With increasing size of aggregates, (H2O) n?10 10, their thermal stability strengthens. Mechanical stability of great clusters keeps the quickly reached level, and the coefficient of dielectric stability passes through the maximum at n = 50. \\\\Expert2\\NBO\\Journal of Structural Chemistry\\2005, V. 46, N 4, p.626.pdf |
G 15 Galashev, A. E. Computer Simulation of the Stability of Water Clusters Containing Nitrogen Oxide Molecules [Текст] / A. E. Galashev, V. N. Chukanov // Colloid Journal (Translation of Kolloidnyi Zhurnal). - 2004. - Vol. 66, № 5. - С. 523-530 Рубрики: ФИЗИКА Кл.слова (ненормированные): WATER CLUSTERS Аннотация: The stability of water clusters containing nitrogen oxide molecules is studied by the molecular dynamics method. The composition and size of thermodynamically stable heteroclusters are determined. The inclusion of two molecules of nitrogen oxide into aggregates containing seven or more water molecule increases the cluster stability. The correlation between the stability of heteroclusters and the ratio of self-diffusion coefficients of molecules of different kinds is observed. The real part of the cluster permittivity is maximal in the vicinity of the frequency of 200 cm–1. The inclusion of nitrogen oxide molecules into water clusters increases the characteristic frequency of dielectric relaxation. In general, heteroclusters are more stable with respect to perturbations caused by an external electric field than pure clusters with the same number of water molecules. The clusterization of water vapors accompanied by absorption of polar molecules of impurity favors a decrease in the greenhouse effect. \\\\Expert2\\NBO\\Colloid Journal\\2004, V.66, N5,523.pdf |
G 15 Galashev, A. E. Molecular Dynamics Study of Crystallization of Supercooled Liquid Sodium [] / A. E. Galashev, I. P. Chernysheva // Inorganic Materials. - 1999. - V.35, N1. - С. 42-48 Рубрики: ФИЗИКА Кл.слова (ненормированные): STUDY MOLECULAR-DYNAMIC -- CRYSTALLIZATION -- SODIUM -- Na -- SODIUM LIQUID -- SODIUM SUPERCOOLED -- CRYSTAL NUCLEATION -- HOMOGENEOUS NUCLEATION -- SIMULATION -- RUBIDIUM -- Rb -- MODEL Аннотация: Crystallization of supercooled liquid sodium containing a spheroidal bce nucleus was studied by molecular dynamics simulations. The degree of supercooling and the critical nucleus size are determined. After solidification, the system exhibits elasticity of shear. Nucleus growth is accompanied by self-sustained aperiodic temperature oscillations. The radial distribution function is computed and Voronoi polyhedra are constructed for the system immediately before and after the transition. It is shown by the projection method that the crystallized system contains structural defects and Features a long-range order |
G 15 Galashev, A. E. Atomic dynamics and the size of metal clusters [] : a computer experiment / A. E. Galashev // Surface (Russia). - 1997. - N2. - С. 5-13 Рубрики: ФИЗИКА Кл.слова (ненормированные): DYNAMICS ATOMIC -- CLUSTERS METAL -- Na -- Al -- Pb -- CRYSTAL Аннотация: A computer study of atomic dynamics of metal clusters Na229, Al201 and Pb201 whose intial packing corresponded to extended crystals was carried out. The change of mobility in the radial direction of clusters was inverstigated. A reduction in lattice parameters of clusters Al201, Pb201 and some increase of the size of cluster Na229 have been found |
L 79 Liquid-crystal phase transition in granular films of binary alloys [] : II. Kinetics of melting of solid solutions / V. N. Dik, V. P. Skokov, V. P. Koverda, V. P. Skripov // Melts. - 1990. - V.4, N4. - С. 272-277 Рубрики: ФИЗИКА Кл.слова (ненормированные): PHASE TRANSITIONS -- PHASE LIQUID-CRYSTAL -- FILMS GRANULAR -- ALLOY BINARY -- KINETICS OF MELTING -- SOLUTION SOLID -- Pb-Bi -- Pb-In -- MICROSCOPY SCANNING -- POINT MELTING -- MICROSCOPY ELECTRON -- Pb -- In -- Bi Аннотация: The melting of granular films of Pb-Bi and Pb-In solid solutions is inverstigated by scanning-electron microscopy. Size dependeces of the melting points are determined. Possible mechanisms og the melting of small particles of binary alloys are discussed |
B 16 Baidakov, V. G. Nucleation at retrograde condensation [] / V. G. Baidakov, G. Sh. Boltachev // AIP Conference Proceedings. - 2000. - Vol. 534, Is. 1. - 295-298: graph. . - ISSN 0094-243X Рубрики: ФИЗИКА Кл.слова (ненормированные): NUCLEATION -- CONDENSATION -- SURFACE TENSION -- RETROGRADE CONDENSATION Аннотация: A binary Van-der-Waals solution is considered. Within the framework of the Gibbs and Van-der-Waals capillary theories under the conditions of constancy of the temperature and the composition the sise dependences of surface tension s(R) are calculated for critical nuclei of liquid and vapor. The phenomenon of "closure" of size dependences s(R) and the presence anomalously of high maximums on them are established |
P 31 Pastukhov, V. G. Adaptation of loop heat pipes to zero-g conditions / V. G. Pastukhov, Yu. F. Maydanik, Y. G. Fershtater // 6th European Symposium on Space Environmental Control Systems: Noordwijk, Netherlands, 20-22 may 1997 . - 1997. - Vol.400. - С. 385-391 Рубрики: ФИЗИКА Кл.слова (ненормированные): LOOP HEAT PIPES -- HEAT-TRANSPORT -- THERMOCAPILLARY PHENOMENA Аннотация: Loop heat pipes (LHPs) posses a great variety of valuable properties, which make them quite promising for application both on the Earth and in space. Among these are the LHP high heat-transport capacity at an any orientation in the field of mass forces, good mass-and-size parameters and the possibility of an arbitrary configuration of transport lines. At the same time such a drawback of LHPs of the conventional type as the instability of start up and operation in the region of low heat loads reduces their performance. The problem is connected, in a general case, with the unfavourable distribution of the vapor and the liquid phases of the working fluid in the evaporator. There is reason to believe that the LHP operation can also be significantly affected by zero-g conditions, in which the distribution of a working fluid is pre-determined only by the action of surface forces and the thermocapillary phenomena. The paper performs a general analysis of the necessary conditions imposed on the construction of LHP and some designs that contribute to the retention of serviceability in zero-g conditions at low heat loads. It gives the results of laboratory investigations of an adapted ammonia LHP with a heat-transfer capacity up to 2 kWxm |
B 16 Baidakov, V. G. The attainable superheating of nitrogen-helium solutions [Electronic resource] / V. G. Baidakov // Russian Journal of Physical Chemistry A. - 2009. - Vol.83, №10. - P1751-1756 Рубрики: ФИЗИКА Кл.слова (ненормированные): HOMOGENEOUS NUCLEATION -- OXYGEN -- KRYPTON Аннотация: The nucleation of the vapor phase in superheated nitrogen-helium liquid solutions was studied by lifetime measurements. The temperature dependences of the mean lifetime of metastable solutions were obtained at p = 0.5 and 1.0 MPa and several concentrations. The nucleation rate J was found to vary from 10(4) to 10(8) s(-1) m(-3). The adsorption of the high-volatility component on the metastable liquid-critical bubble boundary was shown to play a determining role in decreasing the temperature of the attainable solution super-heating as the solution concentration increased. The experimental data were compared with homogeneous nucleation theory. Systematic discrepancies were obtained; these discrepancies were related to the influence of the size effect on the surface tension of a nucleus and the work of its formation \\\\Expert2\\nbo\\Russian Journal of Physical Chemistry A, Focus on Chemistry\\2009, v. 83, N 10, p.1751.pdf |
B 16 Baidakov, V. G. Experimental investigations of nucleation in helium-oxygen mixtures / V. G. Baidakov, A. M. Kaverin, G. Sh. Boltachev // Journal of Physical Chemistry B. - 2002. - Vol.106, №1. - С. 167-175 Рубрики: ФИЗИКА Кл.слова (ненормированные): SUPERSATURATED SOLUTIONS -- HOMOGENEOUS NUCLEATION -- SURFACE TENSION Аннотация: The paper presents the results of experimental investigations of nucleation in helium-oxygen gas-filled mixtures. Temperature dependences of the mean lifetime of a mixture in the metastable (superheated) state have been determined, and nucleation rates have been calculated by experiments at fixed pressures of 1.171 and 1.667 MPa and at several values of concentrations. Experimental data are compared with results of the homogeneous nucleation theory in a macroscopic (capillary) approximation and with allowance for the dependence of the properties of nuclei on the curvature of their dividing surface. The size effect of nucleation is taken into account in the framework of the van der Waals, Cahn-Hilliard method. The equation of state of the mixture has been built, and the boundary of stability of homogeneous states, the diffusion spinodal, has been determined. The paper discusses the problems of building a nucleation theory for gas-filled mixtures and states a good agreement between theory and experiment at nucleation rates J similar or equal to 10(7) m(-1) s(-1) when the size effect in nucleation is taken into account |
S 89 Vshivkov, S. A. Effect of molecular dimensions of components on phase transitions in solutions of oligomeric polyethers / S. A. Vshivkov, M. Z. Faizullin // Polymer Science. Series A. - 2009. - Vol.51, №9. - С. 974-978 Рубрики: ФИЗИКА Кл.слова (ненормированные): POLYMER-SOLVENT INTERACTION -- POLYSTYRENE -- REGION Аннотация: The molecular masses and intrinsic viscosities of a series of oligomeric poly(propylene glycols) have been studied by light scattering, analysis of chain ends, viscometry, and the cloud-point method. Phase diagrams are plotted and the Flory-Huggins thermodynamic interaction parameters and the second virial coefficients are calculated for oligomeric poly(propylene glycol)-n-alkane systems. The effects of the molecular dimensions of components on their mutual solubility and positions of boundary curves are determined. UCST decreases with an increase in the size of poly(propylene glycol) macromolecules and increases with an increase in the size of n-alkane mol |
B 16 Baidakov, V. G. On two approaches to determination of the nucleation rate of a new phase in computer experiments / V. G. Baidakov, A. O. Tipeev // Thermochimica Acta. - 2011. - Vol.522, №1-2. - С. 14-19 Рубрики: ФИЗИКА Кл.слова (ненормированные): HOMOGENEOUS NUCLEATION -- MOLECULAR DYNAMICS -- METASTABLE SYSTEMS Аннотация: The present paper gives a comparative evaluation of two approaches to the determination of the homogeneous nucleation rate in molecular dynamics computer experiments, viz. the methods of the mean lifetime of a metastable system and the mean time of the first passage to a cluster of a prescribed size. The crystal nucleation rate in a supercooled Lennard–Jones liquid has been determined in molecular dynamics simulation as a function of pressure at a reduced temperature T* = 0.55. The results of simulation have been compared with classical homogeneous nucleation theory. Good agreement between theory and the results of computer simulation has been found |
B 16 Baidakov, V. G. Comparison of Different Approaches to the Determination of the Work of Critical Cluster Formation / V. G. Baidakov, G. Sh. Boltachev, J. W. P. Schmelzer // Journal of Colloid and Interface Sience. - 2000. - Vol. 231, № 2. - С. 312-321 Рубрики: ФИЗИКА Кл.слова (ненормированные): CRITICAL CLUSTER -- GIBBS' METHOD -- NUCLEATION RATES Аннотация: A comparative analysis of the results of determination of the work of critical cluster formation in nucleation theory for three different methods of evaluation—Gibbs' method, the van der Waals-Cahn and Hilliard, and a newly developed modified Gibbs' approach—is given. As a model system for comparison, regular solutions are chosen. In addition to the work of critical cluster formation, the composition of the critical clusters, their characteristic sizes and the values of the surface tension are determined in dependence on the initial supersaturation in the system or, equivalently, on the size of the critical clusters. It is found, in particular, that, for regular solutions, Tolman's equation cannot serve as a first approximation for the description of the curvature dependence of the surface tension even for large cluster sizes and an alternative formula is developed. It is shown that the latter two mentioned methods of determination of the work of critical cluster formation (the van der Waals-Cahn and Hilliard and the modified Gibbs' approach) lead—at least for the model system considered—to qualitatively and partly quantitatively equivalent results. Nevertheless, differences remain which may lead to quantitative deviations when applied to the determination of the steady-state nucleation rates. The possible origin of such deviations is discussed and some further directions of analysis are anticipated |
B 16 Baidakov, V. G. Attainable superheating of solutions of cryogenic liquids / V. G. Baidakov // Journal of Engineering Thermophysics. - 2007. - Vol.16, №3. - С. 109-118 Рубрики: ФИЗИКА Кл.слова (ненормированные): BOILING-UP -- CRYOGENIC LIQUIDS -- KRAMERS-ZELDOVICH METHOD Аннотация: The kinetics of spontaneous boiling-up of superheated binary solutions of cryogenic liquids is studied. Within the framework of the Kramers-Zeldovich method, an expression is obtained for the steady state rate of homogeneous nucleation in a solution that takes into account free-molecular and diffusion regimes of the substance supply to a growing bubble. Viscous and inertial forces are also taken into account in the study of the nucleus growth dynamics. The work of critical nucleus formation is determined within the framework of the Gibbs and van der Waals capillarity theories. The dependence of the surface tension of critical bubbles in the solution on their size is investigated. The temperature of attainable superheating and nucleation rates in superheated solutions of cryogenic liquids with complete or partial solubility of the components are determined by a method of lifetime measurement. The experiments were conducted in a wide range of pressures and solution concentrations. The measurement results are compared with the theory of homogeneous nucleation taking or not taking into account the size effect in nucleation. It has been found that, by taking into account the size dependence of the surface tension of a nucleus, better agreement between the theory and experiment is obtained. The boundary of essential instability of the solution, that is, the diffusion spinodal, is computed |