Search

The methods for fabrication of the functionally-gradient materials, which have a high complex of unique mechanical, technological and special properties, when they working on impact, wear, fatigue, experiencing increased cyclic and alternating loads, are reviewed. Considered materials are used in aerospace engineering, energy, and other industries characterized by extremely unfavourable, extreme operating conditions of critical parts, structural elements, and assemblies. Different methods for fabrication of the gradient structures are considered, in particular, the method of severe plastic deformation of metals and the process of active bending of copper. The effect of grain size, texture, and grain-growth gradients on the deformation mechanisms and mechanical properties of gradient- nanostructured nickel, as well as functionally-gradient ceramic materials are studied. The review may be of interest to researchers and scientists in the field of materials science, metallurgy, and nanotechnology.

Background: Intercomponent drug interactions could play important role for drug release, membrane permeability and membranotropic action. Therefore, newly developed drugs need for checking their biopharmaceutical characteristics. A new analgetic drug based on paracetamol (Actimask® Acetaminoprofen) and a hepatoprotector N-acetyl-D-glucosamine has been developed, with increased safety and potentiation of the analgesic effect (Ruban O., 2022). Multibilayer lipid membranes were chosen as promising testing medium due to their proved appropriation and sensitivity for study multi-compound drug-membrane interactions. It is the basis for a kinetic approach allowing elucidation of biopharmaceutical interactions in model membrane medium. Objectives: Revealing changes of paracetamol release and membrane penetration in the new paracetamol-glucosamine analgetic drug as well as estimation the rationale of the approach developed to trace biopharmaceutical interactions in model membrane medium. Materials and Methods: L-a-dimyristoyl phosphatidylcholine (DMPC) multibilayer membrane was used as a model biomimetic testing medium. Differential scanning calorimetry (DSC) was applicated to trace kinetics of drug-membrane interactions. Results: Gelatin as a part of Actimask® increased the characteristic time of paracetamol diffusion about threefold, but it had no pronounced effect on the equilibrium paracetamol penetration into the membrane. Sole glucosamine manifested no membranotropic effect under the experimental conditions, however, in combination with gelatin, it sufficiently reduced equilibrium paracetamol penetration while paracetamol diffusion remained within the experimental error. The full drug formulation increased membrantoropic effect by 34 % in compared with sole paracetamol. Conclusions: Glucosamine and gelatin can affect both kinetic and equilibrium parameters of paracetamol-membrane interactions, while the full set of the drug components is able to increase the effect which correlates well with the previously established enhancement of analgetic effect of the drugs. The approach developed allows accurate tracing of drug release and membrane penetration depending on a set of drug components. Generally, the results obtained prove the rationale of applying the approach to pre-clinical drug examination.

A new thermodynamic approach for phase stability of a nanoscale material under irradiation taking into account Gibbs free energy of phase formation and nucleation is proposed. The influence of powder dispersion and vacancy saturation on the radiation stability and phase changes of spherical Ferrum nanoparticles during irradiation is determined. The paper shows the possibility of a radiation-induced α-Fe → y-Fe polymorphic transition, and also defines the radiation stability zones of Ferrum nanoparticles. It is shown that the competition between the energy of the accumulated vacancies in the particle, the bulk energy of the phase transformation, and the surface energy of the particle is responsible for the specific behavior of irradiated nanocrystalline Ferrum. [ABSTRACT FROM AUTHOR]

Copyright of National Academy of Sciences of Armenia Reports / Doklady Nacionalnaâ Akademiâ Nauk Armenii is the property of National Academy of Sciences of the Republic of Armenia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article provides an abstract review of patents. The results of creative activity of scientists, engineers and specialists, including inventions in the field of nanotechnology and nanomaterials, being implemented, allow achieving a significant effect in construction, housing and community services, and related sectors of the economy. For example, the invention «Method for liquidphase synthesis of nanostructured ceramic material in the CeO2 –Sm2 O3 system to create a solid oxide fuel cell» can contribute to the active development of alternative, hydrogen energy. Fuel cells have a wide range of applications – from batteries in portable electronic devices to large-scale power generation and autonomous use (for example, in remote areas). Power plants based on fuel cells are almost twice as economical as traditional ones. Their efficiency can reach 85%, and the amount of harmful emissions is almost 100 times lower due to the lack of direct chemical contact of the fuel with the oxidizer. The specialists can also be interested in the following inventions in the area of nanotechnologies: method of increasing the tensile strength of fiber composites by means of preliminary modification of carbon fibers with carbon nanotubes and molecules containing amino groups; preparation method of pure silver nanowires; towards safe and sustainable innovation in nanotechnology; method of distribution of carbon-based nanoparticles in the production of nanocomposite unidirectional thermoplastic tapes; device for reducing the impact of vibration and shock effects on the performance of technological equipment; high-density three-dimensional electrically conductive micro- and mesoporous material based on carbon nanotubes and / or low-layer graphenes and a method for its preparation; nanotechnology as a viable alternative for the removal of antimicrobial resistance determinants from discharged municipal effluents and associated watersheds; and others.

The increasing popularity of carbon nanotubes has created a demand for greater scientific understanding of the characteristics of thermal transport in nanostructured materials. However, the effects of impurities, misalignments, and structure factors on the thermal conductivity of carbon nanotube films and fibers are still poorly understood. Carbon nanotube films and fibers were produced, and the parallel thermal conductance technique was employed to determine the thermal conductivity. The effects of carbon nanotube structure, purity, and alignment on the thermal conductivity of carbon films and fibers were investigated to understand the characteristics of thermal transport in the nanostructured material. The importance of bulk density and cross-sectional area was determined experimentally. The results indicated that the prepared carbon nanotube films and fibers are very efficient at conducting heat. The structure, purity, and alignment of carbon nanotubes play a fundamentally important role in determining the heat conduction properties of carbon films and fibers. Single-walled carbon nanotube films and fibers generally have high thermal conductivity. The presence of non-carbonaceous impurities degrades the thermal performance due to the low degree of bundle contact. The thermal conductivity may present power law dependence with temperature. The specific thermal conductivity decreases with increasing bulk density. At room temperature, a maximum specific thermal conductivity is obtained but Umklapp scattering occurs. The specific thermal conductivity of carbon nanotube fibers is significantly higher than that of carbon nanotube films due to the increased degree of bundle alignment.

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This short communication is dedicated to memory of Rostislav Mikhailovich Grechishkin, an outstanding Soviet and Russian physicist, a specialist in the field of magnetic phenomena, Dr. of physical and mathematical Sciences, Professor of the Applied Physics Department at the Faculty of Physics and Technology of Tver State University, head of a scientific school in magnetoelectronics.

Copyright of National Academy of Sciences of Armenia Reports / Doklady Nacionalnaâ Akademiâ Nauk Armenii is the property of National Academy of Sciences of the Republic of Armenia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Today, using of nanostructured materials in microelectromechanical systems (MEMS) is very perspective. One of such materials is anodic aluminum oxide that has electrical and mechanical properties not worse than other materials that are currently used in manufacturing of MEMS devices. This article presents the results of research in methodology and measurement of Young's modulus of free aluminum oxide films.

Copyright of Refrigeration Engineering & Technology is the property of Odesa National University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The bioluminescent enzymatic bioassays for assessment of nanomaterial biotoxicity using the soluble or immobilized coupled enzyme system of luminous bacteria NAD(P)Н:FMN-oxidoreductase + luciferase (Red + Luc) as a test system were employed in this study. This method specifically detects the toxic properties of substances based on their effect on the parameters of the bioluminescent enzyme reactions. The commercially available metal nanoparticles (MNPs), including silver nanoparticles (Ag), nanoparticles of silicon dioxide (SiO2), and titanium dioxide (TiO2), of different sizes were tested in the study. The inhibitory effects of MNPs on the bioluminescent Red + Luc enzyme system were measured. Results indicated that the soluble Red + Luc coupled enzyme system was more sensitive to the inhibition effect of MNPs than its immobilized form. The inhibitory activity of MNPs decreased in the following order: Ag > TiO2 > SiO2. That correlated well with results of other biological methods. Due to substantial advantages such as technical simplicity, short response time and high sensitivity to analysis, this bioluminescent enzymatic bioassay has the potential to be developed as a general bioassay for safety assessment of a wide variety of nanomaterials

Copyright of News of Kazakhstan Science / Novosti nauki Kazahstana is the property of NCSTE (JSC National Center for State Scientific and Technical Evaluations) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article provides the results of the electrochemical preparation of metallic silver nanoparticles. The process was carried out in distilled water using silver electrodes. The laser analyzer determined the size of metallic silver particles as 3-35 nm. Average particle size was obtained with an electron microscope was 10 nm.

Nanostructured metal-carbon composites (NMCC) have been prepared by reduction of HAuCl4 in pores and upon external surface of carbon matrix. The influence of different factors on dispersity of metallic phase has been investigated. NMCC phase composition and average crystallite size were determined by X-Ray Diffraction Method. Functionsof particles sizes distribution were calculated on Small-Angle X-Ray Scattering curves. Porous structure parameters were estimated on the basis of adsorption-desorption isotherm of nitrogen at 77 K. Optimal conditions of NMCC production preventing significant decreasing of specific surface and pores volume of carbon matrix during their filling with gold nanoparticles were established.

The report given the results of the preparation of nanoparticles of nickel hydroxide by an electrochemical method, in distilled water and potassium hydroxide, using nickel electrodes. The novelty of the work lies in systematic studying of the preparation process of the preparation of nickel hydroxide nanoparticles by an electrochemical method. The particle size was determined by dynamic light scattering and X-ray diffraction analysis.

The use of nanostructured materials and activated methods of surface engineering for creation of modern technics objects. The principles of control of forming rocesses of structure and phase in the materials and coatings in the presence of nanosized modifying particles are described. The scientific and technological bases of the formation of structure and properties of surface layers under the action of thermal, mechanical, chemical, electrophysical factors in the realization of various surface engineering methods (electrochemical deposition, gas-thermal spraying, microarc oxidation, friction plating, ion beam implantation, tribomechanical modification) are shown. The examples of application of the developed nanostructural materials and coatings with high physico-mechanical and tribological properties for production of friction assemblies of various technical objects are shown.

Using system approaches provides essential development of traditional methods in materiology and their effective application for objects with difficult multiscale structure and for nano-structural materials as well. It shows application of complex physical and chemical analysis, multifractal and wavelet analysis to describe material structures in qualitative and quantitative way, which allows revealing the differences poorly distinguished with other separate methods and estimating system characteristics of material structures and characterizing the process in self-organizing in structures. Formation by tearing of friction surface structures for composite materials with additives of Al2O3 and SiC is described in comparable thermodynamic conditions. Adding SiC in comparison with Al2O3 promotes to a lesser extent fragmentation and increase in frequency of setting and breaking processes. Adding graphite to reinforced SiC composite material results in increase in nonequilibrium of thermodynamic condition of structure formation. Additional introduction of graphite in even greater degree strengthens distinctions between materials with SiC and Al2O3 additives, which results in formation of the least ordered structures of friction surface.

The state diagrams elements analysis of the physicochemical system states according to the suggested topological model enabled to define the self-organization principles at pattern and phase formation. The topological model elements have been studied on the ground of the undissociated compound stages being isolated from the dissociated ones with a singular point formed on the state diagram. The rational stage sequence of structures, phases and layers interfacing has been viewed from the structure and energy positions: fractal surface structure growth; an increased number of fractal base elements; fractal meander complication; layer percolation in the interfacial area; fractal degeneration. A multifractal approach to the different structures quantification has been recommended which was realized through the measure of set approximating the structure under study. Wavelet analysis has been suggested to describe the nanostructures of the materials with the features and parameters of the wavelet analysis influencing the material description being defined.

The heat capacity of nanoclusters was treated using thermodynamics of surfaces, taking into account the surface enthalpy introduced by E. Guggenhein. It is shown that the cluster heat capacity Cp should be greater then the capacity C(b)p of the corresponding bulk phase. However, the Cp/C(b)p ratio should not exceed 25-30% up to very small clusters containing 100 atoms. So, experimental data on metallic nanoclusters and nanostructures demonstrating that Cp exceeds C(b)p in 2-5 times are incorrect.

The methods of obtaining nanostructured materials using equal-channel angular pressing, mechano-chemical alloying, modification of materials and coatings by nanosized components of different nature (oxides, carbides, nitrides nanodiamonds, carbon nanotubes, fullerenes) are described. The examples of practical use of developed nanomaterials and prospects for expansion of their application in mechanical engineering products are shown.

Considered are atomic force microscopy methods concerning problems of experimental nanomechanics targeted on estimation of physical and mechanical properties of materials in nanovolumes and thin surface layers. Presented are examples of obtaining and interpretation of the contrast AFM-images that allow mapping of of local mechanical heterogeneity of nanostructured materials.

It is established that magnetic soliton – Bloch point – has quantum properties which are manifested in the effects of tunneling and above-barrier reflection in a subhelium temperature range. The conditions of the given phenomena are determined. [ABSTRACT FROM AUTHOR]

In this paper we study ways to control the morphology and properties of zinc oxide nanostructures, which are produced by pulsed electrochemical deposition The effect of mixing of electrolyte, changes in the shape of rectangular pulses of the cathode-substrate potential, as well as the electrolyte composition and duration of the pulsed electrodeposition process on the morphology, crystal structure and optical properties of nanostructured ZnO arrays has been demonstrated. The reasons for the formation by pulsed cathodic electrodeposition without introducing of surfactant growth modifiers into the electrolyte of ZnO arrays, consisting of regular hexagonal nanoplates and their stacks with vertical or horizontal arrangement with respect to the substrates, layers of paraboloid ZnO nanostructures, as well as one-dimensional arrays of zinc oxide, oriented perpendicular to the substrate were analyzed. It was demonstrated by the atomic force microscopy the manufacture of these nanostructured zinc oxide arrays. By the X-ray diffraction and optical spectroscopy the structure and properties of ZnO nanostructures fabricated by pulsed electrochemical deposition were studied. [ABSTRACT FROM AUTHOR]

The peculiarities of the zinc nanosystem formation by means of the low saturated vapor condensation in the high-clean inert medium with the variation of technological parameters, such as the magnetron sputtering discharge power and the plasma-forming gas pressure (Ar) have been studied. By means of the XRD- and the SEM-studies it is determined that the most thin and interconnected zinc nanowires are generated under the plasma-forming gas pressure of 12 Pa and the magnetron sputtering discharge power of 30 W. It is shown that the zinc nanosystem oxidation processes with the most possible preservation of the morphology of the initial structures are possible due to the use of CO2 and O2 gas mixture as an oxidizing medium. [ABSTRACT FROM AUTHOR]

This paper describes the geometric models and presents the calculation results of the actual sizes of Ni and Co anoparticles on the amorphous Si3N4 / Si substrates obtained by thermal annealing of thin metal films using the data of atomic force microscopy. Results were used in the simulation of magneto-optical properties of arrays of nanoparticles. It is shown that processed by described in the paper equations models allow to obtain a good agreement between calculated and experimentally obtained by MOKE method data. [ABSTRACT FROM AUTHOR]

Mesoscopic model, which allows to trace the competition of phase formation in NiAl system according to the equilibrium state diagram, was used for the investigation of the combustion / quenching criterion for SHS-reaction in nanostructured multilayer foils in the conditions of heat outflux. Outflux is realized by two ways: simplified by analytic formula and direct simulation of outflux plates. [ABSTRACT FROM AUTHOR]

Results of the theoretical study of the contributions of self-polarization effect and exciton-phonon interaction to the exciton transition energy in a flat semiconductor nanofilm are presented here. Calculations of the binding and exciton ground state energies are performed using 2H-PbI2 nanofilm embedded in ethylene-methacrylic acid (E-MAA) copolymer. It has been revealed that in ultrathin nanofilms the self-polarization effect contribution to the exciton energy is more than from the interaction with polarizing optical phonons. [ABSTRACT FROM AUTHOR]

Background: State of the art in technique requires the provision of such a combination of strength and plastic properties of metals and alloys, which is difficult to obtain by conventional methods to ensure high-strength state. From this standpoint, formation of metals and alloys of the nanostructure is in some cases the only possible variant. Carbon steel is currently the main construction material; therefore it is of considerable interest to study the characteristics of structure and mechanical properties during the formation the ultra-fine-grained structure in it. Materials and/or methods: A continuous method is developed of wire deformation and nanostructuring. The essence of the method is in applying to a continuously moving wire in the input and output dies a drawing tensile strain, bending and twisting strains to wire passing through a rotating system of rollers. The object of investigation is a high carbon steel wire of 75 type and diameter 3.05 mm. Imposing the strain to wire led to the fragmentation of individual structural components. Their size and the interlamellar distance of obtained ferrite-cementite mixture can be attributed to the class of ultra-fine structure. Results: The main technological parameters of the developed process influencing the formation of ultra- fine wire structures are reduction in the dies and number of twisting revolutions. The obtained results allow determining the impact of technological regimes of the developed method of nanostructuring on the mechanical properties and dimensions of the structural components of the high-carbon steel. The characteristic differences are recognized in mechanical properties of high carbon wire after complex deformation by the developed method and the traditional process of drawing. Modes of nanostructuring are defined by which it is possible to reduce the diameter of the wire without loss of ductility. Conclusion: The implementation of this method does not require complex tools and equipment, but it can be integrated into traditional technological scheme of production of carbon steel wire. [ABSTRACT FROM AUTHOR]

Using molecular layering method and impregnation of silica Asil-300 with copper acetylacetonate, Cu(acac)2, nanocomposites of CuO/SiO2 have been synthesized containing CuO nanoparticles with crystallite size of 36-88 nm and concentration of 1.6-7.4 wt. %. The thermal transformations of surface structures of Cu(acac)2 have been studied by infrared spectroscopy and differential thermogravimetry. Heating the adsorbed Cu(acac)2 and chemisorbed -Cu(acac)-groups up to 550 °C leads to the formation of tenorite - monoclinic copper oxide on silica surface. [ABSTRACT FROM AUTHOR]

The 150-255 keV proton beams transmission through micro- and nanocapillary structures was studied. The dependences of coefficient of proton beam transmission through tapered glass (borosilicate) capillaries with outlet diameters of 5 and 10 µm were obtained. The focusing and guiding effects for transmitted proton beams were observed. The effect of the structure of nanoporous aluminum oxide on the transmission coefficient and angular characteristics of the transmitted ion beam was studied. [ABSTRACT FROM AUTHOR]

The paper describes the optical properties of CdS ultrathin (∼ 50 nm) films, fabricated by the chemical surface deposition on transparent glass substrates. The influence of the atmosphere (Ar2, CdCl2 and air) thermal annealing on the spectral dependence of the CdS films reflection coefficient R(λ) and absorption α(λ) was investigated. The extinction coefficient k(λ), refractive index n(λ), real ε1(λ) and imaginary ε2(λ) parts of the optical dielectric constant of the films annealed in different atmospheres were calculated using the experimental characteristics. The coefficients of Sellmeier equation to describe the n(λ ) dependence in the visible and near infrared spectrum were determined. [ABSTRACT FROM AUTHOR]

Composite materials based on the carbon fiber containing surface oxides and hydroxides as well as metal particles in chitosan film have been obtained by cathode deposition method with the fiber as an electrode. Preparation of the composites has been carried out in two ways: simultaneous deposition of chitosan and metal-containing particles or electrodeposition of metal-containing particles on the carbon fibrous electrode pre-modified with chitosan. The composites have been studied by the X-ray diffraction and X-ray photoelectron spectroscopy methods. It has been shown that the composites of metal oxide/chitosan/carbon fiber includes metallic nickel and amorphous hydroxide whereas copper is presented as metal and oxides. Moreover, formation of Cu(II) complexes with chitosan on the carbon fiber surface is also possible. [ABSTRACT FROM AUTHOR]

Dynamics of structural changes of natural zeolites in their decationation and dealumination has been studied by the IR-spectroscopy and gas chromatography. It is shown that during their processing by acid (HCl) not only deformation and amorphication of zeolites occur but new structural elements are formed. [ABSTRACT FROM AUTHOR]

Nanostructured hydrated WO3 films deposited on glass and on glass with a layer of SnO2 or with Au film have been obtained by chemical and electrochemical methods. The angular and spectral dependences of total internal reflection and surface plasmon resonance for different values of oxide potential have been measured on fabricated planar glass-WO3 and glass-Au-WO3 structures placed in an electrolyte (0,5M H2SO4). These dependences were compared with the results of computer simulation, using experimental values of n and k for these WO3 films, prepared by interferometry. It has been shown that in presence of thin catalyst layer (Pt or Pd) on WO3 surface optical hydrogen sensors for the determination of hydrogen content in air at 0-5 vol.% H2 can be created based on these structures. [ABSTRACT FROM AUTHOR]

Effective (but impracticable in the industrial lithium-ion batteries) ways to improve the cycling parameters of Si-electrodes are high end charge potentials or high charge rates, i.e. reducing the time spent at low electrode potentials vs. Li+/Li0. These methods are widely used in academic researches without regard to the practical applicability of the results. We have shown experimentally that by suppressing the crystallization of a-SiLix in Si4Li15 and by stimulating formation of amorphous or nanostructured states of lithium - silicon alloys one can significantly improve the electrochemical parameters of silicon electrodes of lithium-ion batteries in cycling mode usually applied to real batteries. Peculiarities of the behavior of electrochemical system Si/Li have been substantiated by the results of quantum-chemical calculations of cluster models for SinLim alloy as dependent on the Si : Li ratio. Thus, the spatial and electronic structure of nanoclusters Sin (n = 2-16) and SinLim (n = 4, 8, 12, 16; m = 2-54) have been examined theoretically. [ABSTRACT FROM AUTHOR]

Effective (but impracticable in the industrial lithium-ion batteries) ways to improve the cycling parameters of Si-electrodes are high end charge potentials or high charge rates, i.e. reducing the time spent at low electrode potentials vs. Li+/Li0. These methods are widely used in academic researches without regard to the practical applicability of the results. We have shown experimentally that by suppressing the crystallization of a-SiLix in Si4Li15 and by stimulating formation of amorphous or nanostructured states of lithium - silicon alloys one can significantly improve the electrochemical parameters of silicon electrodes of lithium-ion batteries in cycling mode usually applied to real batteries. Peculiarities of the behavior of electrochemical system Si/Li have been substantiated by the results of quantum-chemical calculations of cluster models for SinLim alloy as dependent on the Si : Li ratio. Thus, the spatial and electronic structure of nanoclusters Sin (n = 2-16) and SinLim (n = 4, 8, 12, 16; m = 2-54) have been examined theoretically. [ABSTRACT FROM AUTHOR]

Phase transformations of nanostructured 1-octadecene and 10-undecylenic acid were studied by thermophysical methods, FTIR spectroscopy and X-ray diffraction. It was shown that bulk as well as nanostructured 1-octadecene crystallizes in orthorhombic unit cell. However, the unit cells of 10-undecylenic acid in bulk and inside the porous silicon are differen, but with the same large period of the pattern. The transition between orthorhombic crystalline and orthorhombic rotation-crystalline phases in boundary layer takes place at -60°C for nanostructured 1-octadecene and at -95°C for nanostructured 10-undecylenic acid. At the same time, the melting temperatures decrease in the confined media comparing to bulk for both substances (? = 11°C and ΔT = 19°C, respectively). [ABSTRACT FROM AUTHOR]

Recent literature data on investigation of structure and properties of porous film materials, including thermostable ones, based on synthetic polymers have been generalized and systematized. Modern classification of porous polymer materials and methods of investigation of their porous structure have been presented. [ABSTRACT FROM AUTHOR]