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Kinetics and mechanism of the low-energy β-a phase transition of the second kind in 2,4-dinitroanisole

Defence Technology（防务技术） 2024年第10期40卷 210-224页

作者： Aleksandr V.Stankevich nikolay a.rasputin Anisa KhRudina Gennady L.Rusinov Vera I.Filyakova Valery N.Charushin I.Ya. Postovsky Institute of Organic Synthesis Ural Branch of the Russian Academy of Sciencesekaterinburg 620108russia Russian Federal Nuclear Center-Zababakhin All-Russia Research Institute of Technical Physics snezhinsk 456770russia Kazan National Research Technological University kazan 420015russia

In this work, comprehensive studies of 2,4-dinitroanisole(2,4DNAN) were carried out using powder thermorentgenography of the internal standard. The time of the complete polymorphic transition in the solid phase β→a in 2,4DNAN under various combinations of conditions has been determined. It has been established that, regardless of the season of manufacture of the substance, when it is stored for 8-9months, with a change in ambient temperature from minus 30℃ to plus 30℃, a complete polymorphic transition β→a occurs. When stored in conditions below minus 5℃, polymorphic transition does not occur. When stored in conditions above plus 30℃ in a closed container, polymorphic transition occurs within 3 weeks. The polymorphic transition is accompanied by a decrease in density by 1.3%-1.5% and an increase in melting temperature by 10-12℃, depending on the degree of purity of the starting substance. The activation energy of the molecular rearrangement was 68-70 k J/mol(16.5 ± 3 kcal/mol). The mechanism of polymorphic transition has been evaluated, which is presumably based on internal homodiffusion and energy transfer to the surface of the mass of powder particles and the product. The average activation energy of the polymorphic transition process was 110 ± 6.2 k J/mol(26.2 kcal/mol). In an open container, reactions proceed by a homogeneous mechanism, and in a closed container by a heterogeneous mechanism involving the gas phase.

关键词： Energetic materials Melt-castable 2,4-Dinitroanisole Polymorphic transition Kinetics Mechanism Homodiffusion Sublimation

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Plasma-assisted oxidation of benzoic acid

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Frontiers of Chemical Science and Engineering 2020年第4期14卷 513-521页

作者： Anna Khlyustova nikolay Sirotkin Laboratory of Chemistry of Hybrid Nanomaterials and Supermolecular Systems G.A.Krestov Institute of Solution Chemitry of Russian Academy of SciencesIvanovo 153045Russia

Plasma-assisted oxidation of organic com-pounds is one of the developing technologies for wastewater *** effectively accelerate degradation processes due to plasma generated reactive species and ultra-violet *** of BA in aqueous solutions by the atmospheric pressure glow discharge and underwater diaphragm discharge was studied and monitored by fluorescence and spectrophoto-metric *** type and solution pH affect the formation rates of mono-and dihydroxybenzoic *** derivatives were formed only by glow discharge *** yields of hydroxyl radical were estimated on the kinetics data for the hydroxylation of benzoic *** steps of the hydroxylation processes and further oxidation were described.

关键词： atmospheric pressure glow discharge under-water diaphragm discharge oxidation benzoic acid hydroxyl radical

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Saffman–Taylor instability in eccentric cylinders at gaseous cavitation

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Friction 2024年第2期12卷 356-362页

作者： Anatoliy A.MONAKHOV nikolay BUKHARIN Institute of Mechanics Moscow State UniversityMoscow 119899Russia ThermoFluid Solutions Ltd. CalgaryAlberta T3G4E8Canada

A flow of silicon fluid in the gap between eccentric cylinders was studied *** condition of gaseous cavitation inception during the rotation of internal cylinder was *** was shown that at reduction of the gap between cylinders Saffman–Taylor instability appeared on surface of the internal cylinder and then gaseous cavitation was *** of one uniform gas formation appearance under this type of instability was demonstrated.

关键词： gaseous cavitation Saffman-Taylor instability eccentric cylinders friction lubrication theory

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EXISTENCE OF SOLUTIONS OF nTH-ORDER NONLINEAR DIFFERENCE EQUATIONS WITH GENERAL BOUNDARY CONDITIONS

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Acta Mathematica Scientia 2020年第1期40卷 226-236页

作者： Alberto CABADA nikolay DIMITROV Departamento de Estatística Análise Matemática e OptimizaciónInstituto de MatemáticasFacultade de MatemáticasUniversidade de Santiago de CompostelaSantiago de CompostelaGaliciaSpain Depatment of Mathematics University of RuseRuse 7000Bulgaria

The aim of this paper is to prove the existence of one or multiple solutions of nonlinear difference equations coupled to a general set of boundary *** to do this,we construct a discrete operator whose fixed points coincide with the solutions of the problem we are looking ***,we introduce a strong positiveness condition on the related Green's function that allows us to construct suitable cones where to apply adequate fixed point *** we have the general existence result,we deduce,as a particular case,the existence of solutions of a second order difference equation with nonlocal perturbed Dirichlet conditions.

关键词： difference equation multiplicity of solutions Green's function positive solutions parameter dependence

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Optimal control of natural resources in mining industry

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International Journal of Mining Science and Technology 2015年第2期25卷 193-198页

作者： Petrov nikolay Tanev Angel Electrical Engineering Electronics and AutomationTechnical University-Sofia Faculty of Mathematics and Informatics Sofia University

The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine＇s maintenance. Fol- lowing the proposed optimal control model, a sensitivity analysis has been performed that includes the interest rate impact on the optimal solution. This study shows that the increasing of the interest rate sti- mulates faster extraction of the resources. The discounting factor induces that the resource has to be extracted faster hut this effect is counterbalanced by the diminishing returns of the annual cash flow. At higher parameters of ＂alpha＂ close to one of the power function about 80% from the whole resource will be extracted during the first 4 years of object/mine maintenance. An existence of unique positive root with respect to return of investment has been proposed and proved by two ways： by the ＂method of chords＂ and by using specialized software.

关键词： Optimal control Natural resources Interest rate Sensitivity analysis Method of chords

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Ultrathin coating of particles in fluidized bed using submicron droplet aerosol

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Particuology 2020年第6期18卷 23-29页

作者： Maksim Mezhericher Christian Rieck nikolay Razorenov Evangelos Tsotsas Mechanical and Aerospace Engineering Princeton UniversityPrincetonNJ 08544USA Thermal Process Engineering Otto-von-Guericke University39106 MagdeburgGermany Mechanical Engineering Shamoon College of EngineeringBeer Sheva84100Israel

In this work,we demonstrate that particles can be coated in a fluidized bed w让h coating solution provided by a novel aerosol *** droplets are smaller than 1 pim in volume-based diameter,hence they are very much smaller than droplets in conventional spray fluidized bed processes(around 40μm).A proof-of-principle experiment with 30%aqueous coating solution of sodium benzoate and γ-Al2O3 core particles in 150 mm fluidized bed fed with droplet aerosol supplied from the chamber side is *** simultaneously coat and dry the particles,inlet of fluidization air was at 50℃ .Moreover,Monte Carlo simulations of coating with small aerosol and large spray droplets were *** to dramatically smaller building blocks,ultrathin particle coating of high-resolution(very small layer thickness)can be attained with the new aerosol process,with the potential of even going *** coverage of particles is reached substantially faster than in the conv entional process,so that material dema nd is much lower and sensitive materials can be processed in short reside nee *** yield of around 30%was much higher than expected,that is considered to be technically viable and may be enhanced by the recycling of entrained solids or better equipment design.

关键词： Aerosol Fluidized bed Particle Submicron droplet Ultrathin coating

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FINITE TIME BLOW UP OF THE SOLUTIONS TO BOUSSINESQ EQUATION WITH LINEAR RESTORING FORCE AND ARBITRARY POSITIVE ENERGY

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Acta Mathematica Scientia 2016年第3期36卷 881-890页

作者： nikolay kutev natalia kolkovska milena dimova Institute of Mathematics and Informatics Bulgarian Academy of Sciences 1113 Sofia Bulgaria

Finite time blow up of the solutions to Boussinesq equation with linear restoring force and combined power nonlinearities is studied. Sufficient conditions on the initial data for nonexistence of global solutions are derived. The results are valid for initial data with arbitrary high positive energy. The proofs are based on the concave method and new sign preserving functionals.

关键词： Boussinesq equation with linear restoring force finite time blow up arbitrary high positive energy combined power nonlinearities sign preserving functionals

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EXISTENCE OF SOLUTIONS OF NONLOCAL PERTURBATIONS OF DIRICHLET DISCRETE NONLINEAR PROBLEMS

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Acta Mathematica Scientia 2017年第4期37卷 911-926页

作者： Alberto CABADA nikolay D.DIMITROV Instituto de Matemdticas Facultade de MatemdticasUniversidade de Santiago de Compostela15782 Santiago de CompostelaSpain Department of Mathematical Analysis University of Rousse7017 RousseBulgaria

This paper is devoted to the study of second order nonlinear difference equations. A Nonlocal Perturbation of a Dirichlet Boundary Value Problem is considered. An exhaustive study of the related Green＇s function to the linear part is done. The exact expression of the function is given, moreover the range of parameter for which it has constant sign is obtained. Using this, some existence results for the nonlinear problem are deduced from monotone iterative techniques, the classical Krasnoselski fixed point theorem or by application of recent fixed point theorems that combine both theories.

关键词： Dirichlet boundary value problem nonlocal perturbations Green's function parameter dependence

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Control of chaotic oscillations of a satellite

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Applied Mathematics and Mechanics(English Edition) 2007年第7期28卷 893-900页

作者： Alexey Bobtsov nikolay Nikolaev Olga Slita Department of Control Systems and Informatics Saint-Petersburg State University of Information Technologies Mechanics and OpticsKronverksky Ave.49Saint-Petersburg197101Russia

Analytical conditions and practical methods of their realization are proposed to solve a problem of a command signal tracking for a nonlinear disturbed system. Nonlinear disturbed plants consisting of linear dynamic block and nonlinear block in feedback are considered. Nonlinear part of the plant and disturbance are unknown and bounded. The paper illustrates a possibility of applications of proposed algorithms to control libration angle of satellite.

关键词： adaptive control chaotic behaviour satellite control nonlinear stabilization nonlinear control output control

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Biogenic Amorphous Silica as Filler for Elastomers

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Journal of Renewable Materials 2018年第4期6卷 402-412页

作者： nikolay Dishovsky Petrunka Malinova Ivan Uzunov University of Chemical Technology and Metallurgy-Sofia 8 St.Kliment Ohridski Blv.1756 SofiaBulgaria Institute of General and Inorganic Chemistry Bulgarian Academy of SciencesAcad.G.Bonchev Str.bl.111113 SofiaBulgaria

Natural products from agricultural wastes are finding importance in the polymer industry due to their many advantages such as being lightweight,low cost and environmentally *** the present study the potential of the two types of rice husk ash(RHA)prepared under different conditions as fillers in natural rubber-based elastomer composites was *** fillers were prepared by rice husks incineration and characterized by means of X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),scanning electron microscope(SEM),Brunauer-Emmett-Teller(BET)specific surface area,Hg-porosimetry and *** evaluation involved determining the vulcanization characteristics of the compounds and their physical and mechanical characteristics,resistance to thermal aging as well as the dynamic properties of the vulcanizates containing *** has been found that the ash from rice husk has good potential as filler in elastomers,especially as a substitute for synthetic commercially available *** improves the grip on ice and snow better than standard silica and may be used in formulations for shoe soles used for winter sports,extreme hiking footwear,ski boot soles,winter tire protectors,*** quality depends on the conditions under which rice husk is *** is recommended to run the process at a temperature not higher than 800°*** particular,cases in which the vulcanizates contain biogenic silica have very interesting characteristics like improved modulus at 300%of elongation,lower residual elongation,higher mechanical loss angle tangent at 0°C and lower at 60°C,and are superior to those of the vulcanizates containing commercially available filler Ultrasil?7000 GR.

关键词： Rice husk ash fillers natural rubber mechanical characteristics dynamic properties

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