Wyniki wyszukiwania - Biblioteka Nauki

1

Alginate-based hydrogels modified with graphene oxide and hydroxyapatite for cartilage tissue regeneration

100%

Lach A. , Skoczeń M. , Ordon K. , Pielichowska K.

Engineering of Biomaterials

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2018

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tom Vol. 21, no. 148

52

2

Manufacturing of composites samples with graphene

100%

Wiśniewski A. , Sałacińska A. , Szymański R. , Kunikowska A.

Prace Instytutu Lotnictwa

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2016

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tom Nr 4 (245)

262--270

EN

The article presents the state of knowledge within the scope of graphene production used in polymer matrices composites, as well as methods of obtaining graphene for these composites, including chemical method. The way of obtaining graphene in form of planes with dimensions of90 x 100 mm and the method of manufacturing multilayer composite with graphene were presented. Composites were produced from carbon fiber-epoxy resin prepregs in out of autoclave process. The adhesive film were used as an additional component which allows to transfer of graphene plane on carbon-epoxy resin prepregs and facilitate the consolidation process. In terms of the quality analysis of prepared composite samples results of ultrasonic tests of composites plate without the graphene and with graphene as an A-scan, B-scan, C-scan, S-scan were shown. The use of ultrasonic methods of registration: C-scan type amplitude of the echo and bottom echo signal amplitude, that allows to detect manufacturing defects caused by the mismatch of parallel edges of carbon prepregs, were engaged. The analysis of C-scan images allows to determine the accuracy of the angular orientation of the carbon layers.

PL

W artykule przedstawiono stan wiedzy w zakresie wytwarzania grafenu do zastosowań w kompozytach o osnowach polimerowych, a także metody pozyskiwania grafenu dla tych kompozytów, w tym metodę chemiczną. Przedstawiono sposób pozyskiwania grafenu w formie płaszczyzn o wymiarach 90x100 mm, a także metodę wytwarzania wielowarstwowego kompozytu z grafenem. Kompozyty wytwarzano z preimpregantów węglowo-epoksydowych w procesie bezautoklawowym. Zastosowano klej błonkowy, jako dodatkowy składnik kompozytu pozwalający na przeniesienie płaszczyzn grafenowych na preimpregnat węglowo-epoksydowy oraz ułatwiający proces konsolidacji kompozytu. W zakresie wykonanych analiz jakości przygotowanych próbek kompozytowych przedstawiono wyniki badań ultradźwiękowych płyt kompozytowych bez grafenu i z grafenem w postaci: A-scan, B-scan, C-scan i S-scan. Przedstawiono użycie metody ultradźwiękowej z rejestracją typu C-scan amplitudy echa oraz amplitudy echa dna, która pozwala na wykrycie wad produkcyjnych powstałych w wyniku niedopasowania równoległego krawędzi preimpregnatu węglowego. Z analizy obrazów typu C-scan określono dokładność kątową ułożenia warstw węglowych.

3

Atomic layer deposition of HfO2 on graphene from HfCl4 and H2O

100%

Alles H. , Aarik J. , Aidla A. , Fay A. , Kozlova J. , Niilisk A. , Pärs M. , Rähn M. , Wiesner M. , Hakonen P. , Sammelselg V.

Open Physics

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2011

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tom 9

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nr 2

319-324

EN

Atomic layer deposition of HfO2 on unmodified graphene from HfCl4 and H2O was investigated. Surface RMS roughness down to 0.5 nm was obtained for amorphous, 30 nm thick hafnia film grown at 180°C. HfO2 was also deposited in a two-step temperature process where the initial growth of about 1 nm at 170°C was continued up to 10–30 nm at 300°C. This process yielded uniform, monoclinic HfO2 films with RMS roughness of 1.7 nm for 10–12 nm thick films and 2.5 nm for 30 nm thick films. Raman spectroscopy studies revealed that the deposition process caused compressive biaxial strain in graphene, whereas no extra defects were generated. An 11 nm thick HfO2 film deposited onto bilayer graphene reduced the electron mobility by less than 10% at the Dirac point and by 30–40% far away from it.

4

Extraordinary magnetoresistance: sensing the future

100%

Hewett T. , Kusmartsev F.

Open Physics

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2012

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tom 10

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nr 3

602-608

EN

Simulations utilising the finite element method (FEM) have been produced in order to investigate aspects of circular extraordinary magnetoresistance (EMR) devices. The effect of three specific features on the resultant magnetoresistance were investigated: the ratio of the metallic to semiconducting conductivities (σ M/σ S); the semiconductor mobility; and the introduction of an intermediate region at the semiconductormetal interface in order to simulate a contact resistance. In order to obtain a large EMR effect the conductivity ratio (σ M/σ S) is required to be larger than two orders of magnitude; below this critical value the resultant magnetoresistance effect is dramatically reduced. Large mobility semiconductors exhibit larger EMR values for a given field (below saturation) and reduce the magnetic field required to produce saturation of the magnetoresistance. This is due to a larger Hall angle produced at a given magnetic field and is consistent with the mechanism of the EMR effect. Since practical magnetic field sensors are required to operate at low magnetic fields, high mobility semiconductors are required in the production of more sensitive EMR sensors. The formation of a Schottky barrier at the semiconductor-metal interface has been modelled with the introduction of a contact resistance at the semiconductor-metal interface. Increasing values of contact resistance are found to reduce the EMR effect with it disappearing altogether for large values. This has been shown explicitly by looking at the current flow in the system and is consistent with the mechanism of the EMR effect. The interface resistance was used to fit the simulated model to existing experimental data. The best fit occurred with an interface with resistivity of 1.55×10−4 m (overestimate). The EMR effect holds great potential with regard to its future application to magnetic field sensors. The design of any such devices should incorporate high mobility materials (such as graphene) along with the specific features presented in this paper in order to produce effective magnetic field sensors.

5

Raman modes in transferred bilayer CVD graphene

100%

Niilisk A. , Kahro T. , Kiisk V. , Rähn M. , Alles H. , Aarik J. , Sammelselg V.

Open Physics

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2015

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tom 13

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nr 1

EN

A systematic experimental Raman spectroscopic study of twisted bilayer graphene (tBLG) domains localized inside wide-area single layer graphene (SLG) produced by low-pressure CVD on Cu foil and transferred onto SiO2/Si substrate has been performed. According to the Raman characterization the tBLG domains had a great variety of twisting angles θ between the bottom and top graphene layers (6° < θ < 25°). The twisting angle θ was estimated from the spectral position of the rotating R and R' modes in the Raman spectrum.Under G band resonance conditions the breathing mode ZO' with a frequency of 95- 97 cm−1 was detected, and a breathing mode ZO was found in the spectra between 804 cm−1 and 836 cm−1, its position depending on the twisting angle θ. An almost linear relationship was found between the frequencies ωZO and ωR. Also a few other spectral peculiarities were found, e.g. a high-energy excitation of the G band resonance, the 2G overtone appearing at 3170-3180 cm−1 by the G band resonance, revealing a linear dispersion of 80 cm−1/eV of the 2D band in tBLG

6

Er-doped fibre laser mode-locked by mechanically exfoliated graphene saturable absorber

100%

Sotor J. , Sobon G. , Abramski K. M.

Opto-Electronics Review

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2012

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tom Vol. 20, No. 4

362-366

EN

Erbium-doped fibre laser mode-locked by a graphene saturable absorber is presented. Pulses with 630-fs duration and 41.9-MHz repetition frequency were achieved at the centre wavelength of 1562 nm and 9-nm FWHM bandwidth. Multilayer graphene was obtained by mechanical exfoliation from a pure graphite block by using the scotch-tape method and deposited on a fibre ferrule to form a saturable absorber. The laser operated in a mode-locked regime with 37-mW pumping and 4-mW output power.

7

Adhesion of bacterial films on polymer food films covered by graphene oxide emulsion and graphene nanoparticles

100%

Kopczyńska E. , Czerwińska E. , Mitura K. A.

Engineering of Biomaterials

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2018

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tom Vol. 21, no. 148

100

8

Graphene as a material for solar cells applications

100%

Czerniak-Reczulska M. , Niedzielska A. , Jędrzejczak A.

Advances in Materials Science

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2015

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tom Vol. 15, nr 4(46)

67--81

EN

Graphene is a two-dimensional material with honeycomb structure. Its unique mechanical, physical electrical and optical properties makes it an important industrially and economically material in the coming years. One of the application areas for graphene is the photovoltaic industry. Studies have shown that doped graphene can change one absorbed photon of a few electrons, which in practice means an increase in efficiency of solar panels. In addition, graphene has a low coefficient of light absorption 2.3% which indicates that is an almost completely transparent material. In fact, it means that solar cells based on graphene can significantly expand the absorbed spectrum wavelengths of electromagnetic radiation. Graphene additionally is a material with a very high tensile strength so it can be successfully used on the silicon, flexible and organic substrates as well. So far, significant effort has been devoted to using graphene for improving the overall performance of photovoltaic devices. It has been reported that graphene can play diverse, but positive roles such as an electrode, an active layer, an interfacial layer and an electron acceptor in photovoltaic cells. Research on solar cells containing in its structure graphene however, are still at laboratory scale. This is due to both lack the ability to produce large-sized graphene and reproducibility of its parameters.

9

Charakteryzacja struktur grafenowych na podłożach stałych metodami spektroskopowymi

100%

Szybowicz M. , Dychalska A.

LAB Laboratoria, Aparatura, Badania

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2016

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tom R. 21, nr 4

20--27

PL

W pracy przedstawiono wykorzystanie spektroskopii ramanowskiej (mikroskopii ramanowskiej) jako użytecznego narzędzia badawczo-diagnostycznego wykorzystywanego do oceny jakości warstw grafenowych osadzanych na różnego rodzaju podłożach takich jak: SiC, SiO2, szkło, miedź oraz PET. Spektroskopia Ramana jest podstawową metodą eksperymentalną wykorzystywaną do oceny jakości grafenu, jego ciągłości, czy też zdefektowania. W prezentowanej pracy opisano wykorzystanie zmodyfikowanej techniki pomiarów ramanowskich z użyciem pomiarów konfokalnych. Zmodyfikowana technika pozwala na precyzyjny pomiar i uzyskanie dobrej jakości widma ramanowskiego (wysoki stosunek sygnału do szumu) pozwalającego na dokładne i jednoznaczne określenie jaką ilość warstw grafenowych posiada analizowana struktura. Dodatkowo przedstawiono technikę mapowania ramanowskiego wykorzystaną w celu charakteryzacji powierzchni grafenu. Tego typu metoda badawcza pozwala na analizę powierzchni struktury grafenowej w celu zbadania jej jednorodności, określenie potencjalnych defektów, badanie lokalnych zmian związanych z przekrywaniem się struktur mono lub dwuwarstwowych, czy też analizę naprężeń powstających w wyniku oddziaływania grafenu z podłożem, czy też, jak w przypadku elastycznego podłoża PET jego odkształceniom mechanicznym. Zobrazowano również zmiany parametrów warstw grafenowych pod wpływem temperatury w zależności od rodzaju zastosowanego podłoża, na którym osadzono grafen. Badania zostały przeprowadzone na komercyjnych strukturach grafenowych o deklarowanych przez producenta grafenu parametrach określających je jako monowarstwy.

10

Grafen szansą dla mikroinstalacji OZE

100%

Szyjko C. T.

Dozór Techniczny

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2013

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tom z. 4

96--97

PL

Świat boryka się z problematyką energii rozproszonej. Sukces rynku mikroinstalacji OZE jest zdeterminowany przez produkty innowacyjne. Zdaniem naukowców kołem zamachowym polskiej energetyki prosumenckiej może stać się grafen, który sam w sobie może służyć np. za baterię słoneczną. Okazuje się, że rodzima technologia jego wytwarzania jest jedną z wiodących w skali światowej.

11

Effect of Sample Thickness on Carbon Ejection from Ultrathin Graphite Bombarded by keV C_{60}

100%

Golunski M. , Postawa Z.

Acta Physica Polonica A

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2017

|

tom 132

|

nr 2

222-224

EN

Molecular dynamics computer simulations are employed to investigate the effect of a sample thickness on the ejection process from ultrathin graphite. The thickness of graphite varies from 2 to 16 graphene layers and the system is bombarded by 10 keV C₆₀ projectiles at normal incidence. The ejection yield and the kinetic energy of emitted atoms are monitored. The implications of the results to a novel analytical approach in secondary ion mass spectrometry based on the ultrathin free-standing graphene substrates and transmission geometry are discussed.

12

Spektroskopia ramanowska grafenu

100%

Grodecki K.

Materiały Elektroniczne

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2013

|

tom T. 41, nr 1

47--53

PL

Grafen jest obecnie materiałem niezwykle popularnym zarówno w środowisku naukowym, jak i w mediach. Jego unikatowe właściwości pozwalają myśleć o nim jako o następcy krzemu w elektronice. Polska ma swój wkład w badaniach tego materiału, między innymi poprzez opracowanie nowatorskiej techniki wzrostu grafenu na SiC- polegającej na osadzaniu warstw węglowych z propanu. Spektroskopia ramanowska jest uznaną i nieniszczącą techniką badań struktur węglowych, w tym grafenu. W sierpniu 2012 r. w ITME został zakupiony spektrometr ramanowski optymalizowany do badań grafenu. W artykule zostaną przedstawione podstawy spektroskopii ramanowskiej i omówione pokrótce podstawowe techniki wytwarzania grafenu. Główny nacisk został położony na przedstawienie możliwości badawczych przy użyciu spektroskopii ramanowskiej.

EN

Graphene is a material that has recently become very popular with both the representatives of the scientific world and the media. The unique properties of graphene make it a successor to silicon in a new generation of electronics. Poland has contributed to the study of this material, among others by developing an innovative technique of graphene growth on SiC layers by chemical vapor deposition. Raman spectroscopy is a fast and non-destructive technique to analyze and characterize graphene. In August 2012 a new Raman spectrometer dedicated to the study of graphene was bought. In this article the basics of Raman spectroscopy and the graphene production technique are presented. However, the main goal is to show the capabilities and basic techniques of Raman spectroscopy in relation to graphene characterization and analysis.

13

Laser scribing on HOPG for graphene stamp printing on silicon wafer

100%

Butikova J. , Polyakov B. , Dimitrocenko L. , Butanovs E. , Tale I.

Open Physics

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2013

|

tom 11

|

nr 5

580-583

EN

Highly oriented pyrolytic graphite (HOPG) was scribed by pulsed laser beam to produce square patterns. Patterning of HOPG surface facilitates the detachment of graphene layers during contact printing. Direct HOPG-to-substrate and glue-assisted stamp printing of a few-layers graphene was compared. Printed graphene sheets were visualized by optical and scanning electron microscopy. The number of graphene layers was measured by atomic force microscopy. Glue-assisted stamp printing allows printing relatively large graphene sheets (40×40 μm) onto a silicon wafer. The presented method is easier to implement and is more flexible than the majority of existing ways of placing graphene sheets onto a substrate.

14

Defect-minimized directly grown graphene-based solar cells

100%

Cui Y. , Wei J. , Jia L. , Zhang L. , Zhou Q. , Liu Y. , Zhang Y. , Zhang Y. , Yu W.

Materials Science Poland

|

2022

|

tom Vol. 40, No. 3

125--134

EN

Using plasma-enhanced chemical vapor deposition (PECVD) to directly grow graphene nanowalls (GNWs) on silicon to preparate the solar cells is compatible with current industrial production. However, many defects in the GNWs hinder improvement of the power conversion efficiency (PCE) of solar cells. In this work, we found that the defects in GNWs can be reduced under the condition of keeping the appropriate sheet resistance of GNWs by simultaneously reducing the growth temperature and increasing the growth time. Then, a PCE of 3.83% was achieved by minimizing the defects in the GNWs under the condition of ensuring adequate coverage of GNWs on bare planar silicon. The defects in GNWs were further reduced by adding a poly(3,4-ethylenedioxythiophene) (PEDOT):Nafion passivation coating, and the PCE was significantly improved to10.55%. Our work provides an innovative path and a simple approach to minimize the defects in graphene grown directly on silicon for high-efficiency solar cells.

15

Characteristics of pure Love mode SAW sensor with graphene interdigital transducer for biosensing applications

100%

Chen C. , Wang X. , Wang Y.

Journal of Theoretical and Applied Mechanics

|

2022

|

tom Vol. 60 nr 4

551--559

EN

The characteristics of Love wave biosensors are systematically investigated. The results show that sensors with combination of a ZnO guiding layer and 90ST or 90AT Quartz substrates exhibit purer Love modes than those with the SiO2 guiding layer. The corresponding maxi- mum sensitivities are −10.9069 and −11.641m2/kg, respectively, which are nearly two times higher than those of SiO2 layer. The ZnO/90ST Quartz Love wave sensor exhibits the largest K2 of 0.3022 and achieves 0 ppm/oC of TCF at hZnO/λ = 0.0216. The sensor employing the Graphene IDT further improves the sensitivity by nearly one order of magnitude.

16

Remarks on theoretical modelling of spin-dependent electronic transport in carbon nanotubes and graphene

100%

Krompiewski S.

Open Physics

|

2011

|

tom 9

|

nr 2

369-371

EN

This contribution reports on charge and spin transport through graphene nanoribbons (GrNs) and carbon nanotubes (CNTs). The paper focuses on the giant magnetoresistance effect in these materials, and their potential usefulness for spintronic applications. As examples, the following devices are shortly discussed: GrNs in the ballistic transport regime, a CNT-based Schottky-barrier field effect transistor (CNT SB-FET), as well as CNT quantum dots in the Coulomb blockade limit.

17

The impact of unmodified graphene - based substrates on basic properties of human umbilical cord-derived mesenchymal stem cells in vitro

100%

Noga S. , Moździerz A. , Sekuła M. , Karnas E. , Jagiełło J. , Madeja Z. , Lipińska L. , Zuba-Surma E.

Engineering of Biomaterials

|

2018

|

tom Vol. 21, no. 148

83

18

Aqueous biological graphene based formulations for ink-jet printing

100%

Dybowska-Sarapuk Ł. , Rumiński S. , Wróblewski G. , Słoma M. , Młożniak A. , Kalaszczyńska I. , Lewandowska-Szumieł M. , Jakubowska M.

Polish Journal of Chemical Technology

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2016

|

tom Vol. 18, nr 2

46--52

EN

The aim of the study was to produce heterophasic graphene nanoplatelets based formulation designed for ink-jet printing and biomedical applications. The compositions should meet two conditions: should be cytocompatible and have the rheological properties that allow to apply it with ink-jet printing technique. In view of the above conditions, the selection of suspensions components, such as binder, solvent and surfactants was performed. In the first stage of the research the homogeneity of the dispersion of nanoplatelets and their sedimentation behaviour in diverse solutions were tested. Subsequently, the cytotoxicity of each ink on human mesenchymal stem cells was examined using the Alamar Blue Test. At the same time the rheology of the resulting suspensions was tested. As a result of these tests the best ink composition was elaborated: water, polyethylene glycol, graphene nanoplatelets and the surfactant from DuPont company.

19

Development of Graphene Based Flow Sensor

100%

Kowalski A. , Safinowski M. , Szewczyk R. , Winiarski W.

Journal of Automation Mobile Robotics and Intelligent Systems

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2015

|

tom Vol. 9, No. 4

55--57

EN

This paper shows the research on a flow sensor based on graphene. Presented Results show the linear relation between voltage induced on graphene layer and flow velocity. The measurement shows that signal level is relatively low, and it is highly correlated with the time of the sample being submerged in water. A significant temperature dependency has been shown which indicates on necessity to develop a compensation system for the sensor. On the other hand, induced voltage is related to ion concentration of the liquid, so the sensor must be recalibrated for every working environment. The most important thing that turned out during research is that although the voltage signal itself is highly inconsistent, the difference between its value in steady state and for flowing liquid is always visible and correlated to the flow value – this property can be used in further deployment. Huge advantage of the sensor is also its scalability which opens so far unknown possibilities of applications.

20

40 years of the Institute of Electronic Materials Technology

100%

Skoczek P. , Plasota S.

Materiały Elektroniczne

|

2019

|

tom T. 47, nr 1-4

23--29

EN

The origin of the Institute of Electronic Materials Technology (ITME) dates back to the 1970s. In 1970 the Scientific-Production Center of Semiconductors CEMI (NPCP) came into being. Comprising the TEWA Semiconductor Factory, the Institute of Electron Technology and the Industrial Institute of Electronics.