Wyniki wyszukiwania - Biblioteka Nauki

1

Dynamical properties of C-60(H2O)(50) mixture cluster. Molecular dynamics simulation

100%

Dawid A. , Sokol M. , Gburski Z.

Materials Science Poland

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2005

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tom Vol. 23, No. 2

421--427

EN

A small cluster composed of fifty water molecules evenly spread out over the surface of fullerene (C-60) has been studied by the MD simulation. The radial distribution function and velocity autocorrelation functions ( linear and angular) of water molecules have been calculated. Both the solid and liquid phases of a water layer surrounding the fullerene molecule have been investigated. The simulation suggests that a plastic phase ( active rotations and frozen translations of water molecules) of such a specific, ultrathin water layer develops at a low temperature, T < 22 K.

2

The Anodic Behavior of Silver in Concentrated Chloride Solutions

100%

Kołodziej B.

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tom Vol. 74, nr 3

349-360

EN

The processes on the silver electrode during its anodic polarization in concentrated chloride solutions (1,5 - 5,0 M) are identified. The analysis of the potentiodynamic E-I relationships showed, that the anodic polarization depends on the concentration of Cl ions and runs through two steps (peaks A and B). The first step - peak A corresponds to: a/the irreversible electrode reaction involving the adsorption of the reaction product - AgCl in the solution, in which concentration of Cl was less than 2M and b/ the reversible electrode reaction involving the adsorption of the AgCl type species (n=3,4), when the concentration of Cl was more than 4 M. The second step - peak B corresponds to: a/the increase of the passive layer of AgCl showing high porosity and a low ohmic resistance - in the solution in which concentration of Cl was less than 2 M and b/the anodic process, which follows the dissolution-precipitation model, in which the electrochemical reaction of AgCl formation precedes the chemical precipitation of AgCl - in the solution with Cl was more than 4 M. On the basis of experimental functions the values of specific conductivity for the passive layer of AgCl at 4 M and 5 M chloride solutions were calculated. The structure differences of the passive AgCl layer forming in the chloride solutions have been shown by the microscope scanning analysis.

3

Ferromagnetic and structural properties of Ge1-xMnxTe epitaxial layers

100%

Knoff W. , Dziawa P. , Osinniy V. , Taliashvili B. , Domuchowski W. , Diduszko R. , Domagała J. , Łusakowska E. , Jakieła R. , Story T.

Materials Science Poland

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2008

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tom Vol. 26, No. 4

295--300

EN

Magnetic properties of thin layers of p-Ge1–xMnxTe (x < 0.2) semimagnetic (diluted magnetic) semiconductor exhibiting carrier induced ferromagnetism were experimentally studied. The layers were grown on BaF2 (111) substrates by molecular beam epitaxy technique. X-ray diffraction analysis performed at room temperature revealed monocrystalline (111)-oriented rhombohedral (exhibiting ferroelectric properties) crystal structure of Ge1–xMnxTe layers in the entire range of Mn content studied. The examination of the magnetic properties of the layers carried out by superconducting SQUID magnetometry and ferromagnetic resonance technique showed the ferromagnetic transition with the Curie temperature in the range 10–100 K depending on the Mn content and the hole concentration. Contrary to polycrystalline GeMnTe layers, it was experimentally found that in monocrystalline layers of GeMnTe an easy magnetization axis is directed along a normal to the layer plane. This effect is discussed in terms of strain present in these layers due to thermal expansion coefficients mismatch between the substrate and the GeMnTe layer.

4

Ferromagnetic and spin wave resonances in thin layer of expanded austenite phase

100%

Typek J. , Guskos N. , Zolnierkiewicz G. , Berczynski P. , Guskos A. , Baranowska J. , Fryska S.

Materials Science Poland

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2014

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tom Vol. 32, No. 2

198—205

EN

Four samples of austenite coatings deposited by reactive magnetron sputtering on silicon substrate at four different temperatures and pressures were investigated by ferromagnetic resonance (FMR) method at room temperature. The expanded austenite phase S (gN) layers with thickness in the 160 – 273 nm range and concentration of magnetic atoms: 72 % Fe, 18 % Cr and 10 % Ni, were obtained. The coatings with nanometric size grains were strongly textured and grown mostly in [100] direction, perpendicular to the sample surface. Intense FMR spectra were recorded at various angles between the static magnetic field direction and the sample surface. A strong magnetic anisotropy of the main uniform FMR mode was observed and the effective magnetization 4πMe f f determined. Spin wave resonance (SWR) modes were observed in all investigated samples in out-of-plane geometry of the magnetic field. The resonance fields of SWR modes in our samples varied linearly with the spin wave mode number. The value of the effective magnon stiffness constant was determined assuming a parabolic shape of the magnetization variation across the sample thickness.

5

Neural network modeling of thin carbon laser

100%

Szota M. , Jasiński J. , Nabiałek M.

Optica Applicata

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2009

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tom Vol. 39, nr 4

807-813

EN

This paper presents the possibility of using neural networks model for designing a thin carbon layer obtained after carbonizing process in fluidized bed. The carbonizing process in fluidized bed is very complicated and difficult. Very often the structure of the materials is non-homogeneous. This fact and the lack of mathematical algorithms describing carbonizing process makes modeling properties of drive elements by traditional numerical methods difficult or even impossible. In this case, it is possible to try using another nonconventional numerical method such as, e.g., neural network. Using neural networks for modeling carbonizing process in fluidized bed is caused by several nets' features: non-linear character, ability to generalize the results of calculations for data out of the training set. no need for mathematical algorithms describing the influence of changes of input parameters on the modeling properties of materials. This paper presents the manner of designing and preparing neural network structure, choosing input parameters, the way of formatting data in input database and preparing learning and testing. It also presents the method of learning and testing neural networks, the way of limiting nets structure and minimizing learning and testing error. The specially prepared neural networks model vers often is helpful for engineering decisions and may be used in designing carbonizing process in fluidized bed as well as in controlling changes of this process.

6

Ferromagnetic transition in Ge1-xMnxTe semiconductor layers

100%

Knoff W. , Dziawa P. , Osinniy V. , Taliashvili B. , Domuchowski V. , Łusakowska E. , Świątek K. , Story T.

Materials Science Poland

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2007

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tom Vol. 25, No. 2

293--300

EN

Magnetic properties of thin layers of p-Ge1-xMnxTe (x < 0.2) semimagnetic (diluted magnetic) semiconductor exhibiting carrier induced ferromagnetism were experimentally studied. The layers were grown on BaF2 (111) substrates by molecular beam epitaxy technique. X-ray diffraction analysis performed at room temperature revealed monocrystalline (111)-oriented rhombohedral (exhibiting ferroelectric properties) crystal structure of Ge1-xMnxTe layers in the entire range of Mn content studied. The examination of the magnetic properties of the layers carried out by superconducting SQUID magnetometry and ferromagnetic resonance technique showed the ferromagnetic transition with the Curie temperature in the range 10-100 K depending on the Mn content and the hole concentration. Contrary to polycrystalline GeMnTe layers, it was experimentally found that in monocrystalline layers of GeMnTe an easy magnetization axis is directed along a normal to the layer plane. This effect is discussed in terms of strain present in these layers due to thermal expansion coefficients mismatch between the substrate and the GeMnTe layer.

7

Ehnergeticheskaja model' processa ul'trazvukovogo raspylenija v tonkom sloe

88%

Ljashok A. , Jakhno O. , Lugovskojj A.

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nr 5

8

Formation by PECVD of very thin silicon oxynitride [SIOxNy] layers technology and characterisation

88%

Beck R. B. , Cuch M. , Wojtkiewicz A. , Kudla A. , Jakubowski A.

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tom 80

9

Classification algorithms to identify changes in resistance

75%

Duraj A. , Korzeniewska E. , Krawczyk A.

Przegląd Elektrotechniczny

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2015

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tom R. 91, nr 12

80-82

EN

In the article the basic method for measuring the resistance of medical electrodes, made based on a thin conductive layer formed during the PVD process, is described. The authors also briefly characterized two algorithms for data classification: k-nearest neighbors and Bayes classifier, which were used as algorithms to detect changes in the electrode resistance.

PL

W artykule została opisana podstawowa metoda pomiaru rezystancji elektrod medycznych wykonanych w oparciu o cienkie warstwy przewodzące powstałe w procesie PVD. Scharakteryzowano również krótko dwa algorytmy klasyfikacji danych: algorytm k najbliższych sąsiadów oraz klasyfikator bayowski, które zostały wykorzystane jako algorytmy identyfikacji zmian rezystancji elektrod.

10

Mathematical modelling on hot air drying of thin layer fresh tilapia fillets

75%

Guan Z. , Wang X. , Li M. , Jiang X.

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tom 63

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nr 1

EN

The hot convective drying of fresh tilapia fillets was evaluated in a heat pump dryer. The influence of the drying temperature (35, 45 and 55°C), hot air velocity (1.50, 2.50 and 3.50 m/s) and thickness (3, 5 and 7 mm) of the tilapia fillets on the moisture ratio and drying rate has been studied. It shows that drying process took place in falling rate periods. The experimental drying data of fresh tilapia fillets under different conditions was fitted to nine different commonly used thin-layer drying models by nonlinear fitting methods and all the models were compared according to three statistical parameters, i.e. coefficient of determination, the reduced chi-square and the root mean square error. It was found that the coefficient of determination values of Page were higher than 0.99254, and the corresponding reduced chi-square and the root mean square error values were lower than 0.000632219 and 0.023854, respectively, indicating that the Page model is the best to describe drying curves of fresh tilapia fillets among them. Effective moisture diffusivity ranged from 6.55×10–10 to 1.23×10–9 m2/s calculated using the Fick’s second law. With the increase of the drying temperature and the hot air velocity, the effective moisture diffusivities Deff increased. The value of drying activation energy of tilapia fillets with thickness of 3 mm at hot air velocity 2.50 m/s was 17.66 kJ/mol, as determined from the slope of the Arrhenius plot, ln(Deff) versus 1/Ta.

11

Comparison of Field Effect Transistor with C-nPd gate and resistive C-nPd film sensing properties toward hydrogen

63%

Krawczyk S. , Czerwosz E. , Wronka H. , Firek P. , Sochacki M. , Szmidt J.

Przegląd Elektrotechniczny

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2022

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tom R. 98, nr 9

311--313

EN

As a result of the implementation of the POIG project (UDI-POiG.01.03.01-14-071/08-00), the research network Łukasiewicz, the Teleand Radio Institute and the Warsaw University of Technology, developed resistance hydrogen sensors using changes in nanocomposite resistance. Carbon-Palladium films (C-nPd) were obtained by PVD method, followed by transistor sensors (FET) with a gate covered with a previously developed nanocomposite C-nPd film. In this article, we show differences in a sensing properties and reaction of discussed resistance for the transistor sensors with a C-nPd film and resistive sensors built of C-nPd film deposited on ceramic substrate. For both types of sensors we performed sensing characterization in a research set-up prepared especially for this purpose during the implementation of the project. We found that transistor sensor is much more sensitive toward hydrogen than resistive sensor.

PL

W wyniku realizacji projektu POIG (UDA-POIG.01.03.01-14-071/08-00) realizowanego w latach 2009-2015 . Sieć Badawcza Łukasiewicz Instytut Tele- i Radiotechniczny oraz Politechnika Warszawską opracowały oporowe sensory wodoru wykorzystujący zmiany rezystancji nanokompozytowych warstw węglowo-palladowych (C-nPd) otrzymywanych metodą PVD, a następnie sensory tranzystorowe (FET) z bramką wykonaną z opracowanej wcześniej nanokompozytowej warstwy C-nPd. W tym artykule zostały pokazane różnice we właściwościach sensorycznych i ich reakcjach na wodór dla obu typów sensorów tranzystorowego i oporowego w postaci warstwy C-nPd osadzonej na podłożu ceramicznym. Dla obu typów sensorów badania sensorowe były prowadzone na specjalnie do tego celu zbudowanym stanowisku badawczym.

12

Application of DLC layers in 3-omega thermal conductivity method

63%

Wojciechowski K. T. , Zybala R. , Mania R.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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tom Vol. 37, nr 2

512-517

EN

Purpose: The 3-omega method is a unique measuring technique which can be applied for thermal conductivity measurements of bulk materials and layers. In order to measure thermal conductivity of semiconducting and metallic materials (e.g. thermoelectric materials) it is necessary to separate the sensor from the substrate by a dielectric layer. The layer should exhibit thermal conductivity .s comparable or greater than thermal conductivity of characterised materials, as well as good, electrically insulating properties. Design/methodology/approach: The DLC layers were prepared via the magnetron sputtering technique. The reactive sputtering process was carried out in the mixture of Ar and methane (CH4) work gases at the pressure ranging from 0.3 to 0.7 Pa. The layers were deposited on glass and selected thermoelectric materials. The temperature of substrate was controlled in range from 35 oC to 500 oC depending on type of the substrate material. The thickness of received DLC layers was in range from 0.2 to 2 žm. Findings: In order to estimate the accuracy of the modified 3-omega method thermal conductivity measurement results were compared to results of measurements without additional DLC layers and independent data obtained by the laser-flash method. Analysis of experimental results of test measurements show that application of 300 nm thick DLC insulating films allow for characterization of materials exhibiting . < 1.2Wm-1K-1 with the accuracy better than 9%. Research limitations/implications: Results of investigations indicate that prepared DLC layers satisfy requirements of 3-omega method and do not influence significantly on precision and accuracy of thermal conductivity measurements. Originality/value: We have developed the new method of preparation of diamond-like carbon (DLC) layers which satisfy requirements of the 3-omega technique. The layers can be applied for thermal properties measurements of selected thermoelectric materials.

13

Deposition of Thin (Ti,Si)N reflecive layers on textiles substrates

63%

Gielzecki J. , Mania R. , Marszalek K. , Wolanski R.

Przegląd Elektrotechniczny

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2022

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tom R. 98, nr 9

235--238

EN

This paper describes the structure of the device and the method of applying thin (Ti,Si)N layers used as infrared radiation reflectors on fabrics. Ion magnetron sputtering at an average frequency MF (80 kHz) was used as the deposition method. Fabrics covered with thin layers are used for the production of clothes and elements of personal protective equipment dedicated to employees (emergency services, armed forces, metallurgy, mining and others) performing tasks in a hot microclimate environment.

PL

W artykule opisano budowę urządzenia oraz sposób nakładania na tkaniny cienkich warstw (Ti,Si)N stosowanych jako reflektory promieniowania podczerwonego. Jako metodę osadzania zastosowano magnetronowe rozpylanie jonowe o średniej częstotliwości MF (80 kHz). Tkaniny pokryte cienkimi warstwami wykorzystywane są do produkcji odzieży oraz elementów środków ochrony indywidualnej dedykowanych pracownikom (służby ratunkowe, siły zbrojne, hutnictwo, górnictwo i inne) wykonującym zadania w gorącym mikroklimacie.

14

XRF microanalysis of Pb(ZrxTi1-x)O3 type nanocrystalline ferroelectric powders by thin layer method

63%

Jurczyk J. , Zawisza B. , Sitko R. , Buhl F. , Osińska K. , Płońska M.

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tom Vol. 47, No. 6

925-934

EN

A method of wavedispersive XRF analysis of Pb(Zr(x)Ti(1-x))O3 type nanocrystalline ferroelec tric powders (PZT) has been presented. Matrix effects have been minimized by using the thin layer method. Preparation of the nature sample has consisted in digesting 25 mg of the materials in hydrochloric acid and 30% hydrogen peroxide (1 +1), diluting up to 25 mL, and placing 0.5 mL of the obtained solution on a substrate. Standard samples of the same chemical composition but varied masses have been prepared to simplify calibration. Determined elements in nature samples occur within the following concentration ranges: Pb from 66.72% to 69.84%, Zr from 8.54% to 14.04%, and Ti from 3.68% to 9.16%. The detection limits for 0.5 mg samples were obtained: Pb = 1.1 x 10(-3) mg (0.22%), Zr= 1.3 x 10(-3) mg (0.26%), Ti = 2.3 x 10(-4) mg (0.05%).

PL

Opracowano metodę mikroanalizy XRF nanokrystalicznych proszków ferroelektrycznych typu Pb(Zr(x)Ti(1-x))O(3) (PZT). W celu wyeliminowania efektów matrycy zastosowano technikę cienkiej warstwy. Przygotowanie próbek naturalnych do analizy sprowadza się do roztworzenia 25 mg badanego materiału w kwasie chlorowodorowym i 30% nadtlenku wodoru (1 + 1), rozcieńczeniu do objętości 25 mL i nakropleniu 0.5 mL uzyskanego roztworu na podłoże. Do kalibracji wykorzystano wielopierwiastkowe wzorce syntetyczne o tym samym składzie jakościowym lecz różnych masach. Oznaczane pierwiastki występowały w zakresach stężeń: Pb od 66.72% do 69.84%, Zr od 8.54% do 14.04% i Ti od 3.68% do 9.16%. Granice wykrywalności dla 0.5 mg próbki wynoszą: Pb = 1.1 x 10(-3) mg (0.22%), Zr = 1.3 x 10(-3) mg (0.26%), Ti = 2.3 x 10(-4) mg (0.05%).

15

Modelowanie rozkładu pól magnetycznych służących do prowadzenia wiązki plazmy powstającej w wyładowaniach łukowych

63%

Strzyżewski P. , Langner J. , Mirowski R. , Sadowski M. J. , Tazzari S. , Witkowski J.

Przegląd Elektrotechniczny

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2005

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tom R. 81, nr 12

35-37

PL

Prezentowany artykuł przedstawia wyniki symulacji rozkładu pola magnetycznego w obszarze źródła plazmy łukowej oraz w dwóch różnych układach filtrujących mikrokrople (w filtrze magnetycznym typu kolanowego oraz w filtrze typu " T") emitowane z katody w wyniku wyładowania.

EN

The paper concerns modelling of magnetic field distribution in an arc-plasma source and in three different configurations of magnetic channels, designed for the elimination of mico-droplets emitted from a cathode during plasma-arc discharges.

16

Optimization of immovable materiał layer at drying

63%

Didukh V. , Kirchuk R.

Teka Komisji Motoryzacji i Energetyki Rolnictwa

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2007

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tom 07

17

Właściwości elektryczne cienkich warstw a-C:H wytwarzanych metodą nakładania plazmowego z pentanu

63%

Pietrzyk B. , Tyczkowski J.

Karbo

|

2000

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tom Nr 4-5

161-164

PL

Amorficzne warstwy uwodornionego węgla (o-C:H) wytwarzano z par pentanu w trójelektrodowym reaktorze plazmowym z wyładowaniem jarzeniowym o częstotliwości 20 kHz. Przeprowadzono badania przewodnictwa elektrycznego tych warstw. Ustalono, że dominującym mechanizmem przewodnictwa jest generacja Poble'a-Frenkela. Wykazano również brak w badanych warstwach występowania zjawiska przejścia: amorficzny izolator (a-I) - amorficzny półprzewodnik (a-S), obserwowanego we wszystkich innych warstwach wytwarzanych w takich samych warunkach z tctraalkilowych pochodnych wąglowców (Si, Ge, Sn, Pb). Wynik ten pozwoli lepiej zrozumieć naturę przejścia a-I-a-S.

EN

Amorphous films of hydrogenated carbon (a-C:H) generated from pcntanc vapours in tri- electrode plasma reactor with glow discharge with 20 kHz frequency. Electric conductivity of the films has been conducted. It has been determined that Poolc - Frenkcl generation is a dominating mechanism of conductivity. The lack of transfer phenomenon occurrence in investigation films was also determined: amorphous insulator (a-1) amorphous semiconductor (a-S) observed in all other films generated in the same conditions with tctra-alkalinc hydrocarbon derivatives (Si, Gc, Sn, Pb). The result will allow for better under standing of transfer nature a-1 - a- S.

18

Computer-aided identification of the water diffusion coefficient for maize kernels dried in a thin layer

63%

Kujawa S. , Weres J. , Olek W.

International Agrophysics

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2016

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tom 30

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nr 3

19

Próba modyfikacji własności warstw otrzymywanych w procesie sputteringu magnetronowego z wykorzystaniem elementów sterowanych zewnętrznie

51%

Grudniewski T. , Czernik S. , Lubańska Z. , Lichograj R. , Lichograj P.

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tom z. 61, nr 3/II

195--202

PL

Sputtering magnetronowy jest techniką napylania warstw zdobywającą coraz większe zainteresowanie w procesach wytwarzania elementów elektronowych i ogniw fotowoltaicznych. Celem prezentowanych w artykule prac badawczych, była analiza możliwości modyfikacji składu i topografii warstw otrzymywanych w procesie sputteringu magnetronowego z wykorzystaniem elementów sterowanych zewnętrznie. Rolą wprowadzonych do układu elementów zewnętrznych było zaburzenie procesu nanoszenia warstw. Zaburzenie nanoszenia warstw może skutkować pozytywnie, powodując większe uporządkowanie struktury warstwy lub bardziej jednolitą powierzchnię, lub negatywnie - całkowicie uniemożliwiając prawidłowe napylenie warstwy. Oba rezultaty są pożądane z punktu widzenia zastosowań produkcyjnych. Z jednej strony poszukuje się cienkich i jednolitych warstw, a z drugiej - warstw o zmodyfikowanej topografii. W czasie eksperymentów autorzy użyli siatek stalowych oraz przewodników miedzianych umieszczonych w wybranych odległościach od siebie jak i podłoża, a następnie napylali miedź na powierzchnię płytek ze szkła laboratoryjnego. Następnie próbki zostały przebadane przy pomocy mikrosondy wykrywającej skład atomowy substancji i mikroskopu sił atomowych celem analizy zmian w topografii. Autorzy spodziewali się otrzymać warstwy o zwiększonej powierzchni aktywnej. Zgodnie z przewidywaniami autorów otrzymane warstwy okazały się znacznie cieńsze. Interesujący jest natomiast fakt, że ich struktura była bardziej uporządkowana niż na próbce referencyjnej, a ich chropowatość znacznie mniejsza. Podczas eksperymentów nie doszło także do wybijania materiału z dodatkowych elementów wprowadzonych do układu.

EN

Magnetron sputtering is a technic to spray sheets that acquire more interests in electronics and photovoltaic fabrication. The aim of the research presented in present paper was to analyze the possibility of modifying of the layers obtained by the magnetron sputtering - using elements controlled externally. Those elements can modify obtained layers in two different ways: positive by greater orderliness of structure or more uniform surface, or negative causing gaps in sputtered coating. Both results are desirable from the applications point of view. On the one hand seeking to thin and uniform layers on the other layers of the modified topography. During the experiments, the authors used a wire mesh and copper conductors located in some distance from each other and the substrate. Then the samples were tested using the SEM microscope witch detection probe that allow to detect the layer composition substances and atomic force microscope for analysis of changes in topography. Authors hoped to achieve layers with greater active surface area. As authors suspected, sputtered layers were a lot thinner. Interesting fact is that their structure was a lot more ordered than the reference sample, and their roughness was smaller. During the experiment there was no material extraction from additional elements.

20

Wpływ zmiany temperatury na rozkład naprężeń w powłoce naprawianej i w cienkiej warstwie naprawczej

51%

Marcinowski J.

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tom R. 89, nr 3

29--31

PL

Często stosowaną techniką naprawy zdegradowanej powierzchni zbiornika, komina, chłodni czy silosu jest pokrycie tej powierzchni materiałem naprawczym. Jest to zazwyczaj włóknokompozyt na bazie włókien szklanych, bazaltowych lub węglowych o istotnie różnych parametrach rozszerzalności termicznej od materiału powierzchni naprawianej. Przedmiotem rozważań jest określenie rozkładu naprężeń w warstwie naprawianej oraz w powłoce naprawczej w warunkach zmiany temperatury w stosunku do temperatury, w której doszło do połączenia obu warstw. W pracy zaprezentowano wzory na naprężenia wyprowadzone na podstawie ogólnych zasad teorii sprężystości oraz mechaniki naczyń cienkościennych. Przedstawiono przykład numeryczny potwierdzający trafność oszacowania naprężeń za pomocą wyprowadzonych wzorów. W pracy zamieszczono także rozwiązanie numeryczne pewnego realnego problemu inżynierskiego.

EN

A frequently used technique of repairing a degraded area of a tank, chimney, cold store or silo is to cover this surface with repair material. It is usually a fiber composite based on glass, basalt or carbon fibers with thermal expansion parameters which differ significantly from those of the material of the repaired surface. The article discusses the issue of determining the distribution of stresses in the repaired layer and in the repair coat in the conditions of temperature change in relation to the temperature at which the two layers were joined. The paper presents stress formulas derived from the general principles of the theory of elasticity and the mechanics of thin-walled vessels. A numerical example confirming the accuracy of stress estimation using derived formulas is presented. The work also includes a numerical solution to a certain real engineering problem.