Статьи журнала - НБИ технологии
Все статьи: 520
Prospective production ways of new heat-resisting materials based on polyimides
Статья научная
The article is devoted to production and study of materials based on different kinds of industrially manufactured polyimides, including chemical modification of reactivity of multifunctional compounds. The presence of reactive carboxyl, amide and amino groups, capable to interact with multifunctional monomeric and oligomeric modifiers, in macromolecules of polyamide acids, gives the chance of receiving the polyimide materials possessing properties of polymers. As a result, we observe improvement of strength properties and thermal characteristics of new polymeric materials for practical aims.
Бесплатно
Quantumchemical calculation of some diols by method MNDO
Статья научная
Quantum chemical calculation of the molecules of 3,5-di(cyclo-trialumoxandiol)tetraalumoxantetraol-1,1,7,7and 1,7-di(cyclotrialumoxandiol)tetraalumoxantetraol- 1,3,5,7 is executed for the first time by method MNDO with optimization of geometry on all parameters by standardgradient method. The optimized geometrical and electronic structure of these compounds is received. Acid force of 3,5-di(cyclo-trialumoxandiol) tetraalumoxantetraol-1,1,7,7and 1,7-di(cyclotrialumoxandiol)tetraalumoxantetraol-1,3,5,7 is theoretically appreciated. It is established, that it to relate to a class of very weak H-acids (pKa=14) where pKa-universal index of acidity).
Бесплатно
Recent advances on montmorillonite-based fire retardant composites in polymer matrices
Статья научная
Fire retardancy in the future will likely involve a combination of materials that all function as fire retardants but each offers something different. In this paper, it is suggested that a nano-dimensional material, possibly and organically-modified montmorillonite, will be one of the components. Drawing examples from a number of different systems, this is elucidated in this paper.
Бесплатно
Rhizospheric trophic chain: the role and stability in soil processes and ecosystems
Статья научная
The authors have investigated the problems of interactions in the rhizosphere in the context of changing trophic connections, their resilience in ecosystems. It is shown that the dynamics of rhizosphere interactions with changes in environmental conditions becomes the focus of intensive research and the development of continuum enrichment area at the roots and the formation of systems of their interaction in the soil profile.
Бесплатно
Self-organization and entropic s-lines
Статья научная
The concept of the entropy of spatial-energy interactions is used similarly to the ideas of thermodynamics on the static entropy. The idea of entropy appeared on the basis of the second law of thermodynamics and ideas of the adduced quantity of heat. Such rules are general assertions independent of microscopic models. Therefore, their application and consideration can result in a large number of consequences which are most fruitfully used in statistic thermodynamics. In this research we are trying to apply such regularities to self-organization assessing the degree of spatial-energy interactions using their graphic dependence in the form of S-lines. The nomogram to assess the entropy of different processes is obtained. The variability of entropic S -line demonstrations is discussed, in biophysical processes and engineering systems, as well.
Бесплатно
Solution of the diffusion problem in thermocyclic nitrocementation of steel
Статья научная
It is shown that cyclic heating and cooling considerably accelerate the kinetics of chemical thermal processing of steels. The author studies the laws of formation of the strengthened layers at thermocyclic nitrocementation of steel 20 Kh. Production tests of machine parts after chemical thermal and chemical-thermocyclic processings were performed. The structure, phase composition and intensity of wear process of a blanket depending on a number of cycles are investigated.
Бесплатно
Статья научная
Currently the reinforcement of steel surface treatment is widely used in various industries, especially in the automobile. The paper discusses the new economical methods of processing the steel surface, which can significantly improve the properties of the metal.
Бесплатно
Статья научная
The paper deals with structural, morphological and optical properties of nanoproducts which undergone zirconium laser ablation in water and in aqueous SDS solutions. Depending on experiment conditions the indicated products can appear as different crystalline phases of zirconia and organic-inorganic composites, which include SDS alkyl chains intercalated between layers of zirconium oxides or hydroxides. The formation of zirconium dioxide-based hollow nano- and microstructures is demonstrated. It is suggested that ablation-formed gasvapor bubbles can serve as templets for generation of hollow structures.
Бесплатно
Structure and parameters of polyhydroxybutyrate nanofibres
Статья научная
This research work focuses on process characteristics of polymer solutions, such as viscosity and electrical conductivity, as well as the parameters of electrospinning using poly-3-hydroxybutyrate modified by titanium dioxide nanoparticles, which have been optimized. The structure of materials has been examined by means of X-ray diffraction, differential scanning calorimetry (DSC), IR-spectroscopy, and physical-mechanical testing. The fibrous materials obtained can find a wide application in medicine and filtration techniques as scaffolds for cell growth, filters for body fluids and gas-air media, and sorbents.
Бесплатно
Статья научная
It has been shown that the parameters of formation of carbon nanotubes (nanofibers) ring-like structures can be described in the scope of fractal kinetics. In this case the main feature is represented by interactions in polymer matrix at the level of nanofiller. The indicated model explained relatively high degree of bonds between the nanocomposites of polymer/carbon nanotubes at ultra small nanofiller contents.
Бесплатно
Surface-modified magnetic nanoparticles for cell labeling
Статья научная
High potential of the polymer-coated magnetic nanoparticles can be envisioned for many biological applications. The particles can be easily magnetically separated and redispersed in water solutions upon removing of the external magnetic field.
Бесплатно
The aggregation process as a cause of large-scale disorder in nanocomposites of polymer/organoclay
Статья научная
It has been shown that organoclay platelets aggregation in "packets" (tactoids) results in large-scale disorder intensification. It reduces the nanofiller anisotropy degree. In its turn, this factor decreases essentially the nanocomposites reinforcement degree. The interfacial adhesion role in anisotropy level definition has been shown.
Бесплатно
Статья научная
The article discusses issues related to comprehensive development and introduction of technologies such as “smart city”. The authors justify the need of reducing the threats for information security of “Smart city”. In case of implementing smart city technologies, it is necessary to take into account the costs of research of threats from new technologies. Now the universal gateway with a large number of wire and wireless interfaces which performs work on collection and normalization of data from heterogeneous sources is developed. The universal gateway is an infrastructure basis of a network in “the smart city”. In this gateway support of special industrial data interfaces (PLC, DI/DO, etc.), characteristic of SCADA systems is integrated. An integrated approach to development and deployment of smart city projects in Russia will promote increase in information security.
Бесплатно
Статья научная
The quantitative interpretation of the extreme dependence of elastic modulus on the composition of poly(ethylene terephthalate)/poly(butylene terephthalate) blends has been proposed. At this, the authors apply the basics of the percolation theory and fractal analysis. It has been shown that the extreme increase in elastic modulus is due to the corresponding growth of shear strength of blends components during the autohesional bonding. It is noted that the micromechanical models do not give the adequate description of the indicated effect.
Бесплатно
The deformability of polycarbonate / poly (ethylene terephthalate) blends
Статья научная
It has been shown that the extreme enhancement of strain at break for blends polycarbonate/poly(ethylene terephthalate) blends is due to the corresponding structural changes of the indicated blends, which are characterized by their structure fractal dimension variation. The blends deformability rise can be achieved by enhancement of either Flory-Huggins interaction parameter, or shear strength of their autohesional contact. The transparence threshold of macromolecular coils achievement results in sharp reduction of strain at break, i.e. its decrease practically up to zero.
Бесплатно
Статья научная
As it is known, any real fractal object can be simulated as a bulk or surface fractal. In the first case the structure fractality is extended to the entire volume of the object and in the second one - to its surface. For nanocomposites, the matrix of which makes up polymer poly(ethylene terephthalate)/poly(butylene terephthalate) blend, the fractal dimensions of both structure and surface of ring-like formations of nanofiller (multiwalled CNT) were calculated. It has been found out that in case of their notion as bulk fractals, i.e. matrix polymer penetration in ring-like formations internal regions, the strong enhancement of the nanocomposites melt viscosity is observed and in case of surface fractals this parameter is independent on nanofiller contents.
Бесплатно
Статья научная
The effect of different doses of synthetic antioxidant b-(4-hydroxy-3,5-ditertbutylphenyl), propionic acid (phenosan) and savory essential oil on the development of spontaneous leukemia was studied. The drug efficiency was determined from the survival curves, animal life spans, and the incidence of leukemia. Phenosan is characterized by clear antitumor activity in therapeutic (10-4 mol/kg) and ultra-low (10-14 mol/kg) doses. The dose of 10-14 mol/kg increases the life span. The savory essential oil in low doses mixed with drinking water (150 ng/ml) or food (2,5 mg/g) increased the average lifetime of mice by 20-35 %. The low doses of these drugs seem promising as preventive drugs.
Бесплатно
The fractal model of nanocomposites polypropylene / carbon nanotubes melt viscosity
Статья научная
The nanocomposites polypropylene/carbon nanotubes melt viscosity change at nanofiller contents variation was studied. It has been shown that continuous models, developed for polymer composites melt viscosity description, cannot describe this parameter in the nanocomposites case. The correct description of the last rheological properties can be obtained within the frameworks of the fractal model of viscous liquid flow.
Бесплатно
The influence of melafen on structural properties of phospholipid membranes
Статья научная
The paper studies the effect of aqueous solutions of melamine salt of phosphonic acid (Melafen), used in crop production, on structural and thermodynamic properties of phospholipid membranes. The multilamellar liposomes formed from individual synthetic dimyristoylphosphatidylcholine (DMPC), or natural phospholipid mixture (egg lecithin) was studied by differential scanning microcalorimetry (DSC) and small-angle X-ray scattering (SAXS). The method of DSC was used to appraise the influence of Melafen aqueous solutions (10-17 M to 10-3 M) on thermodynamic parameters of lipid melting (temperature, enthalpy and cooperation of phase transition) in suspension of liposomes formed from DMPC. On the basis of DSC data it was concluded that the microdomain structural organization of DMPC membranes was altered by Melafen aqueous solutions as polymodal type. We did not reveal by the SAXS method any noticeable integral structural changes in membranes of egg lecithin in multilamellar liposomes as well as in their stacking parameters (period and degree of order) in Melafen aqueous solutions (10-21 M to 10-6 M). This range of Melafen concentrations is wider than that used in crop production. Relying on the results of this work it can be inferred that microdomain structure of membranes composed of individual neutral phospholipids is changed in Melafen aqueous solutions at the wide concentration range of Melafen. At the same time, Melafen does not affect the overall structure of lipid membranes composed of a natural phospholipid mixture.
Бесплатно
Статья научная
It has been confirmed that properties of polymer materials are encoded by the structure at the molecular level. The impact toughness of poly(ethylene terephthalate)/ poly(butylene terephthalate) blends is controlled by macromolecular coils interactions, which are reflected on the structure of their fractal dimension. It has
Бесплатно
