scholarly journals Carbon Nanoparticles. Production, properties, perspectives of use

2020 ◽  
Vol 21 (1) ◽  
pp. 13-18
Author(s):  
P. P. Maksimyak ◽  
C. Yu. Zenkova ◽  
V. M. Tkachuk

The paper is devoted to the study of the optical properties of carbon nanoparticles synthesized by the method developed during our experimental studies. The optimal conditions for the creation of carbon nanostructures with predetermined properties are defined. Nanoparticles of the size of about 100 nm were obtained, the maximum of absorption of which is localized at wavelengths in the violet-blue region of the spectrum, while the maximum of luminescence – in the green region of the spectrum. The assumption is made about the possibility of using the obtained particles for correlation diagnostics of optical speckle fields.

Author(s):  
В.Д. Минаков ◽  
Р.Н. Голых ◽  
П.В. Петреков ◽  
В.Н. Хмелёв

Современное развитие машино-, приборостроения, медицины, транспорта, авиации и ракетно-космической техники определяется создаваемыми новыми конструкционными материалами с улучшенными механическими свойствами. Основная задача сегодняшнего дня – создание новых образцов материалов путем решения двух взаимоисключающих задач –одновременного обеспечения низкой удельной массы и высоких прочностных свойств материалов. Многообещающим и успешно развивающимся направлением решения этой задачи является создание и применение полимерных материалов, которые оказы-ваются более чем в 5 раз легче традиционных металлов и сплавов. Однако обеспечение необходимых прочностных свойств полимеров невозможно без модификации их физической структуры при помощи ультразвукового воздействия. Существующие способы модификации структуры, основанные на введении химических добавок, улучшая одни свойства материала, ухудшают другие свойства. Поэтому необходимо рассмотреть физические способы модификации структуры. На сегодняшний день одним из перспективных физических способов является ультразвуковое воздействие. В статье описаны результаты экспериментальных исследований по выявлению оптимальной интенсивности ультразвуковых колебаний, обеспечивающей максимальный КПД механодеструкции макромолекул. Выявленные оптимальные условия воздействия (по расстоянию между излучателем и отражателем) позволили обеспечить повышение прочности композита на 44 % по сравнению с неоптимальными условиями, при которых ультразвуковое диспергирование наполнителя повышает прочность на 30%. The modern development of machinery, instrumentation, medicine, transport, aviation and rocket and space technology is determined by the new construction materials created with improved mechanical properties. The main task of today is to create new samples of materials by solving two mutually exclusive tasks - simultaneously ensuring low specific gravity and high strength properties of materials. A promising and successfully developing direction for solving this problem is the creation and application of polymer materials that are more than 5 times lighter than traditional metals and alloys. However, it is impossible to ensure the necessary strength properties of polymers without modifying their physical structure with the help of ultrasonic action. Existing methods of modifying the structure based on the introduction of chemical additives, improving some properties of the material, worsen other properties. Therefore, it is necessary to consider physical ways of modifying the structure. To date, one of the promising physical methods is ultrasound exposure. The article describes the results of experimental studies to identify the optimal intensity of ultrasonic vibrations, providing maximum efficiency of mechanodestruction of macromolecules. The revealed optimal conditions of action (in terms of the distance between the radiator and the reflector) made it possible to increase the strength of the composite by 44% compared with non-optimal conditions under which ultrasonic dispersion of the filler increases the strength by 30%.


RSC Advances ◽  
2014 ◽  
Vol 4 (76) ◽  
pp. 40152-40160 ◽  
Author(s):  
Irene Papagiannouli ◽  
Athanasios B. Bourlinos ◽  
Aristides Bakandritsos ◽  
Stelios Couris

Nanodiamonds (NDs) and carbon-dots (CDs) suspensions exhibit significant NLO response under both ps and ns laser excitation. NDs exhibit important optical limiting action under nanosecond visible (532 nm) and infrared (1064 nm) laser excitation.


1996 ◽  
Vol 217-218 ◽  
pp. 176-180 ◽  
Author(s):  
M. Fujii ◽  
S. Hayashi ◽  
T. Fukumoto ◽  
T. Terami ◽  
K. Yamamoto

2021 ◽  
Vol 23 (39) ◽  
pp. 22673-22684
Author(s):  
Adéla Jagerová ◽  
Romana Mikšová ◽  
Oleksander Romanenko ◽  
Iva Plutnarova ◽  
Zdeněk Sofer ◽  
...  

The high-energy ion irradiation induces the creation of ZnO surface nanostructures affecting optical properties, which may be promising for photocatalysis and optoelectronics.


2016 ◽  
Vol 42 (2) ◽  
pp. 3681-3686 ◽  
Author(s):  
Zhifeng Huang ◽  
Zhihao Wang ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lianmeng Zhang

Author(s):  
A. N. Gavrilov

The problem of modeling complex resource-intensive processes of plasma synthesis of carbon nanostructures (CNS) on the basis of mathematical and numerical methods of solution, focused on the use of parallel and distributed computing for processing large amounts of data, allowing to investigate the relationship and characteristics of processes to obtain an effective, cost-effective method of synthesis of CNS (fullerenes, nanotubes), is an actual theoretical and practical problem. This article deals with the problem of mathematical modeling of motion and interaction of charged particles in a multicomponent plasma based on the Boltzmann equation for the synthesis of ONS by thermal sublimation of graphite. The derivation of the collision integral is presented allowing to perform a numerical solution of the Boltzmann - Maxwell equations system with respect to the arc synthesis of CNS. The high order of particles and the number of their interactions involved simultaneously in the process of synthesis of CNS requires significant costs of machine resources and time to perform numerical calculations on the constructed model. Application of the large particle method makes it possible to reduce the amount of computing and hardware requirements without affecting the accuracy of numerical calculations. The use of parallel computing technology on the CPU and GPU with the use of Nvidia CUDA technology allows you to organize all the General-purpose calculations for the developed model based on the graphics processor of the personal computer graphics card, without the use of supercomputers or computing clusters. The results of experimental studies and numerical calculations confirming the adequacy of the developed model are presented. Obtained quantitative characteristics of the total pairwise interactions between the carbon particles and interactions with the formation of clusters of carbon with various types of ties in the plasma of the interelectrode space which are the basis of the synthesized nanostructures. The formation of carbon clusters occurs in the entire interelectrode space of the plasma with different intensity and depends on the process parameters.


2021 ◽  
Vol 447 (3) ◽  
pp. 18-24
Author(s):  
D.B. Augaliev ◽  
M.K. Erkibaeva ◽  
A.O. Aidarova ◽  
S.А. Tungatarova ◽  
T.S. Baizhumanova

The world's oil reserves are decreasing every day due to the continuous production and processing of the most modern technologies. Scientists all over the world are looking for various raw materials and methods to use the vast resources of natural gas as a substitute for petrochemicals. In this regard, great attention is drawn to natural gas as an alternative source of raw materials for petrochemical industries. The purpose of this work is to study the reaction of methane dehydrogenation on new 20%La-10%Ce20%Mg-50% glycine catalysts prepared by the SHS method to identify the optimal conditions for their preparation, concentration and ratio of metals, the influence of contact time and process temperature on the direction and mechanism of the reaction. The results of the study of 20% La-10% Ce-20% Mg-50% glycine catalyst prepared by the SHS method in the process of oxidative dehydrogenation of methane into C2 hydrocarbons are presented. On the basis of experimental studies, it was found that the composition of the catalyst exhibits high activity in the above reaction under the found optimal conditions. Thus, the influence of reaction temperature on the developed composition of catalysts for oxidative conversion of methane has been determined that the optimum temperature for the selective formation of ethane and ethylene is T=700o С. It was found that for selective oxidation of a mixture of CH4: O2 : Ar in C2 hydrocarbons the optimal conditions are: T=700o С, CH4:O2=2,5:1, 5000 h-1.


2017 ◽  
Vol 18 (3) ◽  
pp. 314-329 ◽  
Author(s):  
Casey J. Lister ◽  
Nicolas Fay

Following a synthesis of naturalistic and experimental studies of language creation, we propose a theoretical model that describes the process through which human communication systems might arise and evolve. Three key processes are proposed that give rise to effective, efficient and shared human communication systems: (1) motivated signs that directly resemble their meaning facilitate cognitive alignment, improving communication success; (2) behavioral alignment onto an inventory of shared sign-to-meaning mappings bolsters cognitive alignment between interacting partners; (3) sign refinement, through interactive feedback, enhances the efficiency of the evolving communication system. By integrating the findings across a range of diverse studies, we propose a theoretical model of the process through which the earliest human communication systems might have arisen and evolved. Importantly, because our model is not bound to a single modality it can describe the creation of shared sign systems across a range of contexts, informing theories of language creation and evolution.


Author(s):  
Владимир Александрович Савчук ◽  
Сергей Ильдусович Валеев

Проведены экспериментальные исследования полей скоростей и давлений в цилиндрическом гидроциклоне для разделения эмульсий с малым содержанием легких примесей (не более 1%). Полученные данные позволяют сделать вывод, что в цилиндрическом гидроциклоне по сравнению с цилиндроконическим гидроциклоном обеспечиваются оптимальные условия для сепарации жидких частиц. Experimental studies of velocity and pressure fields in a cylindrical hydrocyclone for the separation of emulsions with a low content of light impurities (no more than 1%) have been carried out. The data obtained allow us to conclude that in a cylindrical hydrocyclone, in comparison with a cylindrical-conical hydrocyclone, optimal conditions are provided for the separation of liquid particles.


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