Wyniki wyszukiwania - BazTech

1

Carbon nanostructure growth: new application of magnetron discharge

Breus A., Abashin S., Serdiuk O.

Journal of Achievements in Materials and Manufacturing Engineering

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2021

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Vol. 109, nr 1

17--25

EN

Purpose: The application of a common magnetron discharge to the growth of carbon nanostructures is studied. The simplicity of the proposed technique can be beneficial for the development of new plasma reactors for large-scale production of carbon nanostructures. Design/methodology/approach: Graphite cathode was treated by carbon-containing powder accelerated by use of nozzle, and then aged in hydrogen. Superposition of glow and arc discharges was obtained, when putting the cathode under the negative biasing with respect to the walls of a vacuum chamber. The pulsed discharge was preserved through the whole time of treatment. This process was explained in terms of interaction of glow discharge plasma with a surface of the cathode made of non-melting material. Findings: The plasma treatment resulted in generation of the diverse nanostructures confirmed by SEM and TEM images. Spruce-like nanostructures and nanofibers are observed near the cathode edge where the plasma was less dense; a grass-like structure was grown in the area of “race-track”; net-like nanostructures are found among the nanofibers. These findings allow concluding about the possible implementation of the proposed method in industry. Research limitations/implications: The main limitation is conditioned by an explosive nature of nanostructure generation in arcs; thus, more elaborate design of the setup should be developed in order to collect the nanospecies in the following study. Practical implications: High-productivity plasma process of nanosynthesis was confirmed in this research. It can be used for possible manufacturing of field emitters, gas sensors, and supercapacitors. Originality/value: Synthesis of carbon nanostructures is conducted by use of a simple and well-known technique of magnetron sputtering deposition where a preliminary surface treatment is added to expand the production yield and diversity of the obtained nanostructures.

2

On the eigenmodes and eigenfrequencies of low-dimensional degenerated carbon structures: obtaining natural frequencies of ideal and structurally defected systems

Imani Yengejeh Sadegh, Kazemi Seyedeh Alieh, Öchsner Andreas

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 1

193--205

EN

We concentrated on evaluating the vibrational response of ideal and defected degenerated carbon nanostructures under the influence of different boundary conditions. In addition, an attempt has been made to investigate the relative deviation of the natural frequency of imperfect systems and to study the effect of defected regions on vibrational stability of the particles. It has been found that a single and pinhole vacancy defect have the least and the most impact on the natural frequency of nanostructures. Furthermore, the effect of CNT diameter on natural frequencies of low-dimensional systems has also been investigated in this research.

3

Katalizatory heterogeniczne na bazie nanostruktur węglowych w modelowych procesach chemicznych

Latos P., Boncel S., Chrobok A.

Przemysł Chemiczny

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2016

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T. 95, nr 7

1310--1314

PL

Dokonano przeglądu literaturowego dotyczącego zastosowania nanostruktur węglowych jako efektywnych nośników cieczy jonowych. Scharakteryzowano metody immobilizacji cieczy jonowych poprzez wiązanie kowalencyjne fazy aktywnej z powierzchnią nośnika lub poprzez jej adsorpcję na powierzchni zewnętrznej i wewnętrznej. Do praktyki przemysłowej zostały już wprowadzone procesy z udziałem cieczy jonowych jako katalizatorów i rozpuszczalników, dlatego nowe heterogeniczne katalizatory na bazie nanostruktur węglowych i cieczy jonowych mogą mieć w przyszłości duży potencjał aplikacyjny.

EN

A review, with 41 refs., of C nanostructures used as effective carriers of ionic liquids immobilized by formation of covalent bond between active phase and surface of the carrier or by adsorption and then used as new heterogeneous catalysts for synthesis of cyclic carbonates, oxidn. of PhCH(OH)Me to PhAc and in Michael reaction.

4

Molecular order and dynamics of 5CB liquid crystals in confined space - computer simulation

Gwizdała W., Gburski Z.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2015

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Vol. 19, No 1

35--64

EN

We studied the dynamical and structural properties of an important nematic 4-n-pentyl-4’-cyanobiphenyl (5CB) mesogen placed near carbon allotropes (graphene, nanotube), using modeling and molecular dynamics simulations (MD). Every investigated nanosystem (a free cluster of 5CB, a 5CB cluster confined in a single-walled carbon nanotube, 5CB mesogens located between two graphene sheets, a 5CB thin layer on a single-walled carbon nanotube, a thin layer of a 5CB molecules near graphene plane) contains a liquid crystal cluster consisting of 5CB molecules (22–98 molecules). We also performed a computer experiment for a 5CB bulk sample (196 5CB mesogens) with periodic boundary conditions. The following observables were calculated for several temperatures: mean square displacement, radial distribution function and second rank order parameter of 5CB clusters. The obtained results from MD simulations were discussed and compared with the experimental data.

5

Transmission electron microscope studies on carbon nanostructured materials

Pawlyta M.

Archives of Materials Science and Engineering

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2013

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Vol. 63, nr 2

58--67

EN

Purpose: Carbon nanostructured materials are important and still not satisfactorily recognised products. Structure can be investigated with sufficient resolution using transmission electron microscopy but main difficulties are connected with low scattering of electrons by carbon atoms and destruction by knock-on damage caused by collisions of high energy electrons with specimen atoms. Design/methodology/approach: Scanning/transmission electron microscopy (S/TEM) deliver a chance to improve the quality of performed investigations. BF, DF and HAADF detectors were applied for various carbon materials: carbon nanotubes, nano-onions, nanodiamonds and graphitized carbon black. Findings: Obtained results confirmed the usefulness of applied microscopy techniques. Research limitations/implications: Sample preparation is crucial for performed investigations. Because of ionization damage caused by collisions of high energy electrons, results obtained with high-voltage TEM have to be analysed with caution, hence low-voltage electron microscopy is strongly recommended. Originality/value: New and not commonly used techniques were applied for carbon nanostructured materials studies. Advantages and disadvantages of them were compared.

6

Perspektywy wykorzystania surowców węglowych w innowacjach technologicznych

Ludwik-Pardała M.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

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2011

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nr 4

73-86

PL

W artykule przedstawiono stan badań nad możliwością innowacyjnego wykorzystania surowców węglowych, między innymi do wytwarzania energii elektrycznej w węglowych ogniwach paliwowych. Szczególny nacisk został położony na osiągnięcia naukowe w dziedzinie nanostruktur węglowych. Przedstawiono charakterystykę i właściwości materiałów węglowych, takich jak: nanoporowate materiały węglowe, nanorurki węglowe, grafen i fulereny.

EN

The article presents the state-of-the-art on the potential innovative application of coal in electricity generation applying direct carbon fuel cells. Particular emphasis is put on R&D achievements in the area of carbon nanostructures. Presented are the characteristics and properties of such carbon materials as: nonporous carbon materials, carbon nanotubes, graphene and fullerenes.

7

Oznaczanie nanostruktur węglowych w węglach kamiennych i produktach karbonizacji

Shmalko V., Zelensky O. I.

Karbo

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2010

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Nr 3

130-134

PL

Przedstawiono wyniki oznaczania nanocząstek węglowych wyizolowanych z produktów węgla i koksu. Nanocząstki węglowe z produktów karbonizacji posiadają różne rodzaje struktur. Oczekuje się, że nanostruktury węglowe powstają w piecu koksowniczym.

EN

The results to determine the carbon nanoparticles, isolated from coal and coke products were given. Carbon nanoparticles from the products of coking have different types of structures. It is expected that carbon nanostructures are created in the coke oven.

8

Novel Nanomaterials for Prospective Biomedical Applications: Synthesis, Structure and Toxicity

Bystrzejewski M., Rümmeli M.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 7

1219-1255

EN

Magnetic nanoparticles, because of their unique properties, are expected to find many prospective applications including data storage, ferrofluids, catalysis, and biomedicine. In this critical review, synthesis methods as well as the characteristics of magnetic nanoparticles are presented. In addition, the benefits and drawbacks of using nanoparticles in biomedical applications are clearly presented.

9

Nanostruktury węglowe szansą technologii przyszłości

Jasek R.

Zeszyty Naukowe Politechniki Rzeszowskiej. Elektrotechnika

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2006

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z. 29 [233]

173-182

PL

W opracowaniu przedstawiono rozwój badań fizyki i chemii w odniesieniu do technologii materiałowej i informatycznej. W pierwszej kolejności podsumowano budowę strukturalną i elektronową C60. W sposób uproszczony poddano analizie rodzaje fulerenów i możliwości ich zastosowań zilustrowanych przykładami: tranzystora jednocząsteczkowego i pamięci nowej generacji CNT.

EN

Constant increase of the complexity of silicon microsystems, on which the development of the information technology devices depends, is approaching fundamental physic limitations (restrictions). For that reason different ways for replacing silicon with another materials and new technologies are being searched. A very good alternative for silicon can be carbon, especially fullerene C60 and nanotubes/nanopipes iversity of the properties of carbon complexes, obtained due to chemical functionality of C60 gives wide possibilities to obtain new materials, whose properties have not been known before, and employing them to material and computer technologies. New discovered quantum phenomenon of fullerene such as: two-stages quantum process of charge transfer, quantum effect of resistance saturation and hole superconductivity, the effect of the direction change of the electric field in nanotubes/nanopipes placed in the magnetic field give opportunities for creating new generation of transistors. These are mono-molecular transistors, so-called quantum dots, hyperconducting transistors with modulated critical temperature and nanotubes/nanopipes transistors. They can be used as elements of computer equipment and measuring devicesfor measuring hypersensitive electric currents, building capacity standards, double - pole switch. The range of fullerene use is wide and carrying it out depends on the integrated efforts of the experts of many fields. The amazing nanotechnology revolution as well as its practical realization are being currently observed.

10

Funkcjonalizacja chemiczna nanorurrek węglowych

Bystrzejewski M., Pichler T.

Wiadomości Chemiczne

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2006

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[Z] 60, 9-10

569-607

EN

The discovery of carbon nanotubes (CNTs) and the recognition of their exceptional properties have generated a great deal of interest. The possible applications arise from the remarkable properties of CNTs such as the highest Young's modulus, highest thermal conductivity, ballistic electron transport, and field emission resulting from high aspect ratio. The functionalization of carbon nanotubes has become a very actively discussed topic because the CNTs modification is believed to open the road towards real nanotechnology applications. This review with 266 references describes the results on covalent and noncovalent chemical functionalization of carbon nanotubes and related nanostructures. Physical and chemical properties as well as possible applications of functionalized CNTs are also presented.

11

Nowe nanostruktury węglowe : "cebulki", fulereny - "giganty", kapsułki, "strączki grochu"

Bystrzejewski M., Huczko A., Lange H., Baranowski P., Kozubowski J., Woźniak M., Leonowicz M., Kaszuwara W.

Wiadomości Chemiczne

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2004

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[Z] 58, 3-4

163--201

EN

Carbon is a unique material and the research results have taken the subject forward in many new directions in recent years. In addition to the fullerenes, a new allotropic form of carbon discovered in 1985 and produced in macroscopic amount in 1990, carbon nanotubes were found by Iijima in 1991 in a cathode deposit, formed during DC arcing of graphite anode. Since their discovery, the latter ones have captured the imagination of physicists, chemists and materials scientists alike. They are attracted to carbon nanotubes because of their extraordinary electronic and mechanic properties. Further egzo- and endohedral functionalization of fullerenes resulted in a new class of compounds and heterofullerenes were also produced by substitution of carbon atoms in a cage by other (mostly boron and nitrogen) atoms. Recently new intriguing forms of nanocarbous have been also discovered including carbon onions, encapsulates, filled nanotubes, `peapods', etc. In this review these nanocarbons are presented with the emphasis on production techniques and formation mechanisms, structure characterization and the future fields of application. While carbon are, laser ablation and CCVD (Catalytic Chemical Vapor Deposition) are the main techniques to produce these species, they are also formed under quite ditferent experimental conditions which are presented. When one browses through the carbon literature, some other new forms of spheroidal nanocarbons (e.g. nanoflasks, nonohorns, nanofoams...) also crop up again and again and a brief discussion is given here of these most recently discovered nanostructures.