Vladimir Yu Zitserman

• Joint Institute for High Temperatures, Russian Academy of Sciences

This paper deals with the trapping of a particle diffusing in a cylindrical cavity by two circular absorbing spots of arbitrary radii located in the centers of the cavity bases. The focus is on the mean particle lifetime, which is its mean first-passage time to one of the spots. When the spots are small and their radii are well below the cavity rad...

We study diffusion of a Brownian particle in a two-dimensional periodic channel of abruptly alternating width. Our main result is a simple approximate analytical expression for the particle effective diffusivity, which shows how the diffusivity depends on the geometric parameters of the channel: lengths and widths of its wide and narrow segments. T...

We study trapping of particles diffusing in a two-dimensional rectangular chamber by a binding site located at the end of a rectangular sleeve. To reach the site a particle first has to enter the sleeve. After that it has two options: to come back to the chamber or to diffuse to the site where it is trapped. The main result of the present work is a...

The review summarizes the results of the long-term work carried out at the Glushko Thermocenter for the creation of topical databases and the use of new information technologies ensuring the integration of diversified electronic resources. The basic principles of the IVTANTHERMO thermodynamic database and the latest results on the expansion of its...

The article describes new technologies and tools used for drastic upgrading the database THERMAL, one of the oldest thermophysical databases. The database upgrade project provides for a essential expansion of its volume and service capabilities, as well as the possibility of permanently updating the conceptual scheme with the advent of new objects...

The role of the curation process in supporting scientific data repositories is studied. It is shown that curation is an essential element of scientific work in data-intensive disciplines (Earth sciences, biology, materials science, etc.). The scale and importance of curation for scientific archives and databases have led to the emergence of extensi...

The purpose of the paper is to provide a detailed overview of the methods of indexing and categorizing data generated to solve problems in a complex and multifaceted field of knowledge related to the application of nanotechnology. Analysis of the capabilities and restrictions of various categorization methods are applied to the issues of the subjec...

The value of the osmium melting heat, ΔHm= 57.85 kJ/mol, presented in reference handbooks was obtained about 35 years ago from a wide extrapolation (in temperature) of experimental data on the melting entropy of the FCC and the HCP elements of the Periodic Table. Using the correlation of data on the surface tension (developed by B. D. Summ), the me...

Изучена роль процесса курирования в поддержке хранилищ научных данных. Показано, что в дисциплинах с интенсивным использованием данных (науки о Земле, биология, материаловедение и т. п.) курирование является существенным элементом научной работы. Масштаб и значимость курирования для научных архивов и баз данных обусловили появление обширной литерат...

New methods of integrating scientific data on the properties of substances and materials that apply modern information technologies are analysed. The capabilities of systems created using the Semantic Web and Big Data are explored. Despite some differences in the tasks that are solved, both approaches are oriented towards working with large arrays...

A new technology for storage and categorization of heterogeneous data on the properties of matter is proposed. Availability of a multitude of heterogeneous data from a variety of sources justifies the use of one of the popular toolkit for Big Data processing, Apache Spark. Its role in the proposed technology is to manage with extensive data warehou...

Experimental data for the thermodynamic properties of titanium on the melting curve in the pressure range from atmospheric value to 90 GPa are analyzed and brought into correspondence. The problems that have been considered are (i) the lack of data for the solid β-phase density near the normal melting point and (ii) the formation probability of a t...

Compilation and processing of the thermophysical data was always an important task for the nuclear industry. The difficulties of the present stage of this activity are explained by sharp increase of the data volume and the number of new materials, as well as by the increased requirements to the reliability of the data used in the nuclear industry....

Common approaches and technologies applied to digital data storage and processing in various disciplines are analyzed. It is shown that regardless of a specific subject area, working with large data set obtained as a result of experimenting or modeling requires similar methodological support, involving data curation, metadata support, and data gene...

Externally stimulated fluctuations of the size of a particle in an asymmetric environment result in its directional motion. This is demonstrated by considering the particle drift in a periodic symmetric channel, which arises due to fluctuations of the particle size. The emergence of the drift is caused by the time variation of the particle entropy,...

A technique for reconstructing thermal properties, including the melting curve, of refractory metals based on the use of experimental data on caloric properties available up to the melting point and some regularities of the Debye–Grüneisen theory has been proposed. The calculation result is the consistent system of high-temperature thermal data, in...

This paper focuses on trapping of diffusing particles by a sphere with an absorbing cap of arbitrary size on the otherwise reflecting surface. We approach the problem using boundary homogenization which is an approximate replacement of non-uniform boundary conditions on the surface of the sphere by an effective uniform boundary condition with appro...

This article deals with problems of rubrication of dynamically developing directions associated with the permanent appearance of new objects, processes, methods, and technologies. These problems are considered based on the example of spintronics, a new field of solid-state physics that concerns the preservation and transmission of information accor...

This paper outlines the range of problems solved by nanoinformatics, which is a newly originated discipline that combines the methods and tools for the propagation of data on nanomaterials as well as the instruments and technologies based on them. The specific features determined by the interdisciplinary character and rapid evolution of this knowle...

This paper is devoted to particle transport in a tube formed by alternating wide and narrow sections, in the presence of an external biasing force. The focus is on the effective transport coefficients-mobility and diffusivity, as functions of the biasing force and the geometric parameters of the tube. Dependences of the effective mobility and diffu...

Purpose – The purpose of this paper is to reveal main advantages of digital libraries in comparison with technology of common database for data-oriented fields of modern science. As an example, the subject domain “nanomaterials and nanotechnologies” with new features due to evolution of concepts and objects is presented. Design/methodology/approac...

This paper presents a detailed analysis of a newly developed system for the identification of nanomaterials and nanostructures of an arbitrary nature. The system has been created as a result of the joint work of the Committee on Data for Science and Technology (CODATA) and the International Council for Science (ICSI). It is shown that at its core t...

Solar cells of the third generation (after the bulk and thin-film ones that are mainly based on inorganic semiconductors, mostly of silicon) use the leading technologies of the 21st century, including nanotechnologies based on nanomaterials, mainly based on nano-structured or ultrafine inorganic semiconductors, graphene, fullerenes, as well as poly...

The current status and recent results of research aimed at the use of graphene and graphene-based materials in solar cells of various kinds are reviewed. The combination of remarkable properties such as high transparency, high mobility of charge carriers, high mechanical strength, and chemical inertness makes graphene a promising candidate as an el...

The development of studies on the preparation, physicochemical properties, and possible applications of carbon nanomaterials in power manufacturing, conversion, and storage systems is analyzed in this review. The authors continue to study the problem of systematization and attestation of numerical data for nanoscale objects and pay special attentio...

This paper is devoted to the effective transport coefficients of a particle in a tube of alternating diameter. Analytical expressions are derived for the effective mobility and diffusivity under strong bias conditions, i.e., in the limiting case where the external biasing force tends to infinity. The expressions give the transport coefficients as f...

An analysis has been performed of several classifications for an extensive interdisciplinary field of nanotechnology. Objective difficulties have been identified in compiling a priori categorization of subject domain due to the increased volume of information flow in combination with the permanent emergence of new concepts and objects. The concept...

The concept and computer methods for the implementation of new form-linked data technologies for scientific communication are observed. This concept is being advanced by the Internet creator Tim Berners-Lee in the framework of the general idea of the Semantic WEB with the introduction in internet pages of descriptions that are understood by compute...

The problem of the diffusion of particles in a tube consisting of identical units, each composed of a wide and narrow section is solved. With an approach based on reducing the problem to a one�dimensional, the statistics of times of particle transition between adjacent sections is determined, which is a detailed characteristic of the diffusion proc...

Diffusion in a tube of periodically varying diameter occurs slower than that in a cylindrical tube because diffusing particles get trapped in wells of the periodic entropy potential which is due to variation of the tube cross-section area. To quantify the slowdown one has to establish a relation between the effective diffusion coefficient of the pa...

A mechanism for generating a directed motion of a Brownian particle in an asymmetric channel under the action of a varying force field is considered. The setup implementing such a mechanism resembles typical Brownian motors using asymmetry of the energy potential (ratchet effect). It is shown that under certain conditions, the asymmetry of the shap...

This article is devoted to general problems of development of reference data on properties of nanosized objects. It has been shown that the peculiar features of physical characteristics of nanostructures influence the behavior of an expert engaged in building the relevant computer database of property data. The building procedure includes comprehen...

The problem of the motion of a Brownian particle in a periodically tapered tube induced by a time-periodic longitudinal force with zero mean is considered. Under the action of this force, the particle is shown to drift in a direction opposite to the constant load force applied to it. Analytical solutions for the drift velocity, the stopping force (...

This paper reviews general problems appearing in collecting, categorization, and certification of numerical properties data for nanoscale objects. It is shown how their peculiar physical properties affect preparation o f the data at the preliminary stage before moving to detailed data base design. As an examp le, the properties data of carbon nanof...

The common problems of acquisition, classification, and certification of numerical data on the properties of nanoobjects have been considered. The peculiarity of their physical properties is shown to affect the preparation procedure of the informational stock which predates database creation. As an example, the data on the properties of carbon nano...

This paper discusses the Data Center project, which provides integration of the scientific electronic resources (mainly databases) that are developed and supported by the Russian Academy of Sciences. The integration technology has been verified within the framework of the Properties of Substances and Materials interdisciplinary theme, which is repr...

We investigate transport of point Brownian particles in a tube formed by identical periodic compartments of varying diameter, focusing on the effects due to the compartment asymmetry. The paper contains two parts. First, we study the force-dependent mobility of the particle. The mobility is a symmetric non-monotonic function of the driving force, F...

The generalized Fick-Jacobs equation is widely used to study diffusion of Brownian particles in three-dimensional tubes and quasi-two-dimensional channels of varying constraint geometry. We show how this equation can be applied to study the slowdown of unconstrained diffusion in the presence of obstacles. Specifically, we study diffusion of a point...

We study the drift of a Brownian particle in a periodically tapered tube, induced by a longitudinal time-periodic force of amplitude ∣F∣ that alternates in sign every half-period. The focus is on the velocity dependence on the force period, which is usually considered not tractable analytically. For large ∣F∣ we derive an analytical solution that g...

Using Brownian dynamics simulations, we study the effective mobility and diffusion coefficient of a point particle in a tube formed from identical compartments of varying diameter, as functions of the driving force applied along the tube axis. Our primary focus is on how the driving force dependences of these transport coefficients are modified by...

We study the effect of a driving force F on drift and diffusion of a point Brownian particle in a tube formed by identical cylindrical compartments, which create periodic entropy barriers for the particle motion along the tube axis. The particle transport exhibits striking features: the effective mobility monotonically decreases with increasing F,...

The methodical basics of creating information systems on the properties of nanoobjects are developed. It is shown that the main requirement for such systems is the capability of maintaining variations in the logical data structure which is manifested as they permanent change in the nomenclature of the characteristics and identification rules depend...

We show that the effect of driving force F on the effective mobility and diffusion coefficient of a particle in a tube formed by identical compartments may be qualitatively different depending on the compartment shape. In tubes formed by cylindrical (spherical) compartments the mobility monotonically decreases (increases) with F and the diffusion c...

The paper deals with diffusion of a particle in a tube that consists of alternating wide and narrow sections. At sufficiently long times the particle motion can be coarse-grained and described as effective free-diffusion along the tube axis. In the coarse-grained description all the details of the tube geometry are packed into the effective diffusi...

Reduction of three-dimensional (3D) description of diffusion in a tube of variable cross section to an approximate one-dimensional (1D) description has been studied in detail previously only in tubes of slowly varying diameter. Here we discuss an effective 1D description in the opposite limiting case when the tube diameter changes abruptly, i.e., i...

The presence of obstacles leads to a slowdown of diffusion. We study the slowdown when diffusion occurs in a tube, and obstacles are periodically spaced identical partitions with circular apertures of arbitrary radius in their centers. The mean squared displacement of a particle diffusing in such a system at large times is given by ⟨Δx2(t)⟩=2Defft,...

The paper deals with a diffusing particle that escapes from a cavity to the outer world through a narrow cylindrical tunnel. We derive expressions for the Laplace transforms of the particle survival probability, its lifetime probability density, and the mean lifetime. These results show how the quantities of interest depend on the geometric paramet...

The problem of diffusion of particles in a tube with periodically positioned partitions with circular orifices at the center of each was considered. Using an approach based on the methods and results of the theory of diffusion-controlled reactions and the idea of homogenization of the permeability of partitions, we derived a formula for the effecti...

Diffusion of a spherical particle of radius r in a tube with identical periodic dead ends is analyzed. It is shown that the effective diffusion constant follows the Stokes-Einstein relation, D(eff)(r) proportional to 1r, only when r is larger or much smaller than the radius of the dead end entrance. In between, D(eff)(r) not only deviates from the...

This paper examines building and using metadata concerning electronic resources with digital information about the properties of substances and materials. Transformation of the metadata concept as a description of the structure and content of basic information is studied with respect to storage and dissemination of digital data on properties. The m...

We analyze the relaxation of the particle number fluctuations in a membrane channel at arbitrary particle-channel interaction and derive general expressions for the relaxation time and low-frequency limit of the power spectral density. These expressions simplify significantly when the channel is symmetric. For a square-well potential of mean force...

The problem of diffusion in a porous medium with stagnation zones, which reduce the rate of transport of particles, is considered. A method based on the concept of entropy barriers associated with the small size of inlets into the stagnation zone is used to solve the diffusion problem. This method made it possible to reduce the diffusion problem in...

The problem of the diffusion of a particle in a porous medium with dead ends entering which is related to overcoming high entropy barriers is considered. Dead ends effectively decelerate migration, because, while residing in them, a particle does not participate in diffusion transfer. A new approach to the problem was suggested. The approach was ba...

The creation of voluminous databases on the physicochemical properties of substances requires a solution to the general problem of the variability of the logical structure of data. Logical structure variations, which manifest themselves by the differences in the volume, type, and content of data, the appearance of new characteristics, and changes i...

In a hypothetical case of a core melt-down scenarios a very high temperature would be reached (up to 3000 K). In this case, the materials of the core and structural materials (fuel, cladding, metallic alloys, concrete, etc.) could melt to form complex and aggressive mixtures called corium. Modelling of severe accident phenomena, code development an...

A particle diffusing in a tube with dead ends, from time to time enters a dead end, spends some time in the dead end, and then comes back to the tube. As a result, the particle spends in the tube only a part of the entire observation time that leads to slowdown of its diffusion along the tube. We study the transient diffusion in a tube with periodi...

To escape from a cavity through a small window the particle has to overcome a high entropy barrier to find the exit. As a consequence, its survival probability in the cavity decays as a single exponential and is characterized by the only parameter, the rate constant. We use simulations to study escape of Langevin particles from a cubic cavity throu...

The problem of the trapping of diffusing particles by nonoverlapping absorbing patches randomly distributed over a reflecting surface is considered. The suggested approach to its solution is based on the replacement of the inhomogeneous boundary condition on the surface by a radiation boundary condition with an effective rate of trapping the same a...

The escape of a point particle from a cavity of an arbitrary configuration through a small orifice in a cavity wall is considered as a model of entropy barrier overcoming. The dynamics of the particle is determined by collisions with the wall and the dissipative action of the medium. As in reactions with overcoming energy barriers (the Kramers theo...

The partitioning of polyethylene glycol, PEG-3400, from bathing solutions of varying polymer concentrations to α-hemolysin channels is described. While explaining the concentration dependence of the partition coefficient, the nonideality of polymer solution in the pore was found weak, as the overlap volume fraction of the polymer in the pore is hig...

New data on the electrical conductivity and viscosity of aqueous solutions of polyethylene glycol were obtained and used as reference data in studying the ionic channels of biological membranes. Over wide ranges of concentration and polymer molecular weight, conductivity was independent of the molecular weight for long chains and weakly depended on...

The homogenization of boundary conditions on surfaces randomly covered by patches of different sizes and shapes was analyzed. The absorbing disks of two different radii, a=0.05R and a=0.025R, were randomly located on the surface of the sphere, and the particles were initiated uniformly over the surface. The trapping rates were computed for α=0.1, 0...

We analyze trapping of diffusing particles by nonoverlapping partially absorbing disks randomly located on a reflecting surface, the problem that arises in many branches of chemical and biological physics. We approach the problem by replacing the heterogeneous boundary condition on the patchy surface by the homogenized partially absorbing boundary...

Diffusion of a solute in a periodic porous solid is analyzed. An expression for the effective diffusion coefficient is derived for a solute diffusing in a porous medium formed by a simple cubic lattice of spherical cavities connected by narrow tubes. This expression shows how the effective diffusion coefficient depends on microgeometry of the porou...

Electrical conductivity of potassium chloride solutions containing polyethylene glycol PEG of different molecular mass was measured in a wide range of the polymer concentration up to 33 wt. % for PEG 300, 600, 2000, 4600, and 10 000. The data were used to find the dependence of microviscosity, micro , which characterizes the decrease of the ion mob...

A theory of heminal recombination in a cavity containing a reaction center and an orifice that stochastically opens and closes is suggested. A particle broken away from the reaction center diffuses in the cavity until it either escapes through the orifice into the volume or recombines. The model qualitatively describes the special features of sever...

We derive an expression for the effective diffusivity in a model porous medium formed by a periodic array of touching spherical cavities. Our result explicitly links the effective diffusion constant to the microgeometry of the porous material. © 2003 American Institute of Physics.

A method for analytical solution of a base model, which reduces to a diffusion equation with a Gaussian-sink term in the electron transfer theory, is described. The method is constructed as a generalization of the Kramers approach to the problems on the high barrier crossing and is applicable to situations where the reaching of the reaction zone is...

We study the time dependence of the survival probability of a Brownian particle that escapes from a cavity through a round hole. When the hole is small the escape is controlled by an entropy barrier and the survival probability decays as a single exponential. We argue that the rate constant is given by k = 4Da/V, where a and V are the hole radius a...

Molecular dynamics calculations of the shear and bulk viscosity and the self-diffusion constant were made for several states of liquid Na and K along the saturated vapour-pressure curve up to the temperature 1800K. The authors used the effective pair potential between ions developed by Price et al. (1970) with the Ashcroft pseudopotential and the d...

An approach to the theory of chemical reactions under the conditions of slow solvent relaxation is suggested. The approach is a generalization of the Kramers stochastic method and is based on a simplified model of simultaneous evolution of chemical modes and the slow mode of a medium. The obtained equations give a qualitative description of medium...

The problem of escape of a classical particle from a multidimensional potential well due to the influence of random forces is studied. A new solution to the problem is obtained which shows that with fairly large friction anisotropy the qualitative picture of the process principally differs from that underlying the conventional multidimensional Kram...

The dynamics of an elementary reaction step under conditions of ballistic motion along the chemical coordinate and slow adjustment is considered. The process is analyzed within a one-dimensional model describing concurrently the motion along the slow solvent mode and energy diffusion (ED) responsible for over-barrier transitions. When relaxation of...

Smoluchowski equation with a sink term is widely used as a model of a rate process in a slowly relaxing environment. Two approximate solutions for the rate constant obtained for a steeply growing sink are tested numerically using an exponential sink. Both analytical solutions are in a good agreement with the numerical results over a wide range of t...

The turnover behavior of the rate constant as a function of the friction coefficient of the chemical mode is studied in a slowly relaxing environment/solvent. In rapidly adjusting environments, the turnover problem has been solved by Mel'nikov and Meshkov. The reaction dynamics is studied with a special focus on the influence of long-distance recro...

A model for ligand migration within a protein, where the migration is controlled by an escape through a fluctuating bottleneck, has been introduced by Zwanzig (J. Chem. Phys. 97 (1992) 3587) for point ligands. We concentrate on the case where the ligand size is finite and larger than the characteristic thermal width of the bottleneck. An analytical...

Activated rate processes in two dimensions are studied analytically under the condition of weak friction on the reactive mode (energy diffusion) and high friction on the nonreactive coordinate. It is found that the process scenario and, as a consequence, the escape kinetics crucially depend on the strength of the mode coupling. When the coupling is...

A new method is proposed for calculating rate constants for liquid-phase reactions governed by a diffusion equation with a sink. Mathematically, the method consists in the generalized Kramers approach to calculating the process of high-barrier surmounting and applies when the reagents arrive in the reaction zone by the activation mechanism. For two...

When describing the reaction dynamics in a slowly relaxing environment, one has to include slow nonreactive modes of the environment in an explicit consideration along with the “chemical” mode intrinsically responsible for the chemical transformation. This is done within the framework of the Kramers approach to condensed phase chemical reaction dyn...

A simple theory is suggested to describe chemical reactions in which the dynamics of elementary events is controlled by medium relaxation. Model equations treat relaxation as diffusion along a certain mode and take into account sinks and sources. An analytical expression for the rate constant valid at any ratio between relaxation and chemical trans...

The thermally activated escape of a Brownian particle over an arbitrarily shaped potential barrier is considered. Based on an approximate solution of the corresponding Fokker–Planck equation a rate expression is given. It agrees in the limiting case of high friction with the rate following from the corresponding Smoluchowski equation and, in the li...

The Fokker–Planck–Kramers equation for a system composed by a reactive coordinate x coupled to a solvent coordinate y is employed to study the effect of additional degrees of freedom on the dynamics of reactive events. The system is studied numerically in the diffusional regimes of both coordinates, for different topologies of the bistable potentia...

The dynamics of a multidimensional activation process is considered for special conditions when one of the internal modes of a molecule is effectively screened from the solvent and movement along this mode has the character of energy diffusion, whereas for the other modes, movement is described as diffusion in space. Analytical solutions for the ra...