Wyniki wyszukiwania - Biblioteka Nauki

1

Petrographical study of anthracites from European Coal Basins

100%

Kwiecińska B. , Pusz S. , Duber S.

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2002

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tom Vol. 7

149-158

EN

The anthracites from several coal basins occurring in France, Germany, Ireland, Poland, Romania, Russia, Ukraine and United Kingdom were studied in reflected plane-polarised light (Olympus microscope). Three maceral groups (vitrinite, inertinite, liptinite) and associated mineral matter were distinguished. All the anthracites are dominantly composed of vitrinite (75-95%), inertinite is minor (2.5-19%), and liptinite is very rare (up to 1.5%, with one exception - 4.4%). In vitrinite group, the following macerals: collotelinite, telinite, collodetrinite, vitrodetrinite, and pseudovitrinite were recognised. In inertinite group, the most abundant are fusinite and semifusinite.Liptinite in general is dominated by sporinite. In some anthracites, liptinite was not accounted at all, perhaps, in such highly metamorphosed anthracites, sporinite underwent a rapid change in chemical and physical composition, and became optically indistinguishable from vitrinite. In a few samples, sporinite can be recognised from its vitrinite matrix by a distinct optical morphology. Optical microscopical studies of all anthracites revealed significant heterogeneity of the samples, clearly visible under crossed nicols with the use of higher magnifications. This heterogeneity reflects the differences in coal facies, in primary maceral composition, inherited from peat or sub-bituminous stages but also in strain or pressure being distributed inhomogeneously during formation of anthracite. In all cases, heterogeneous microtexture (fine, coarse, granular, mosaic, and fibrous) was observed. Porous and lamellar particles coexist very often together. Coke-like structure, with numerous devolatilization vacuoles, was also recognised. Pyrolytic carbon occurring as veins, sub-parallel to bedding, can be easily noticed in some samples. Pyrolytic carbon types are presumed to originate from volatiles evolved during condensation reactions.Reflectance values (Rmax) of anthracites vary from 2.3% up to 8.9%. These samples which exhibit Rmax higher than 6% were considered as meta-anthracites. It seems, that the latter are made of conglomerates of graphite-like complexes having preferential planar orientation and structurally less organised compounds with typical turbostratic arrangement of the aromatic units.

2

Modelling the bidirectional reflectance distribution functions (BRDF) of sea areas polluted by oil

100%

Otremba Z.

Oceanologia

|

2004

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tom No. 46 (4)

505-518

EN

The paper discusses the possibilities of modelling the bi-directional reflectance distribution function (BRDF) in sea areas polluted by oil. Three sea basin models are considered: a coastal one free of oil, one polluted by an oil film and one polluted by an oil emulsion. The following concentrations of oil were compared: for the film, 1 cm3 of oil per 1 m2 water surface, for the emulsion 1 cm3 of oil in 1 m3 of water. The optical properties of Romashkino crude oil were taken into consideration, as were various angles of incident solar light. The conversion of BRDFs into a directional distribution of the optical contrast of polluted areas is demonstrated.

3

Sensitivity enhancement of metamaterial-based surface plasmon resonance biosensor for near infrared

100%

Pal S. , Prajapati Y. K. , Saini J. P. , Singh V.

Optica Applicata

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2016

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tom Vol. 46, nr 1

131--143

EN

The present study investigates the angular response and sensitivity of a surface plasmon resonance biosensor with metamaterial, by taking the advantage of the remarkable property of metamaterials. The proposed biosensor numerically shows that silver with a metamaterial layer enhances the sensitivity. The thickness of metamaterial and silver layer has been optimized. On comparing these results with a conventional surface plasmon resonance biosensor, it is observed that the sensitivity of the proposed biosensor is improved by introducing the metamaterial. The proposed biosensor has a sensitivity 6.3124 times higher than that of the conventional surface plasmon resonance sensor.

4

Oil-in-water emulsion as a modifier of water reflectance

88%

Otremba Z.

Optica Applicata

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2009

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tom Vol. 39, nr 1

123--128

EN

The paper presents a component of the water reflectance in the visible region, stimulated by oil-in-water emulsion in the concentration of 1 ppm. A proxy for reflectance which is in use in oceanic optics has been studied. A significant change in reflectance for water contaminated by oil emulsion is revealed. In general, the reflectance generated by oil emulsion grows with light wavelength increase and in cases when small oil droplets dominate in oil-emulsion.

5

Electrical and optical properties of nanowires based solar cell with radial p-n junction

88%

Pylypova O. V. , Evtukh A. A. , Parfenyuk P. V. , Ivanov I. I. , Korobchuk I. M. , Havryliuk O. O. , Semchuk O. Y.

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tom Vol. 27, No. 2

143--148

EN

In our studies the absorption, transmittance and reflectance spectra for periodic nanostructures with different parameters were calculated by the FDTD (Finite-Difference Time-Domain) method. It is shown that the proportion of reflected light in periodic structures is smaller than in case of thin films. The experimental results showed the light reflectance in the spectral range of 400–900 nm lower than 1% and it was significantly lower in comparison with surface texturing by pyramids or porous silicon. Silicon nanowires on p-type Si substrate were formed by the Metal-Assisted Chemical Etching method (MacEtch). At solar cells with radial p-n junction formation the thermal diffusion of phosphorus has been used at 790°C. Such low temperature ensures the formation of an ultra-shallow p-n junction. Investigation of the photoelectrical properties of solar cells was carried out under light illumination with an intensity of 100mW/cm2. The obtained parameters of NWs' solar cell were Isc = 22 mA/cm2, Uoc = 0.62 V, FF = 0.51 for an overall efficiency η = 7%. The relatively low efficiency of obtained SiNWs solar cells is attributed to the excessive surface recombination at high surface areas of SiNWs and high series resistance.

6

Optical studies of MOVPE grown GaN layers

88%

Ciorga M. , Jezierski K. , Bryja L. , Misiewicz J. , Paszkiewicz R. , Korbutowicz R. , Panek M. , Paszkiewicz B. , Tłaczała M. , Trabjerg I.

Opto-Electronics Review

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1999

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tom Vol. 7, No. 2

93-95

EN

Photoluminescence and reflectance studies of MOVPE grown GaN samples were performed. From reflectance measurements optical constants were calculated by means of Kramers-Kronig analysis in the energy region 0-6 eV.

7

Wpływ parametrów technicznych instalacji oświetlenia pośredniego z diodami świecącymi na jej parametry świetlne

75%

Pawlak A. , Zaremba K.

Przegląd Elektrotechniczny

|

2013

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tom R. 89, nr 9

278-281

PL

W artykule zaprezentowano wyniki analizy wpływu parametrów technicznych instalacji oświetlenia pośredniego z diodami świecącymi LED na sprawność oświetlenia i jego równomierność. Przykładową instalację oświetlenia pośredniego badano wykonując symulacje komputerowe, które następnie zweryfikowano na podstawie pomiarów rozkładu natężenia oświetlenia w zbudowanym modelu. Wyniki pomiarowe modelu potwierdziły badania symulacyjne, gdyż wyznaczone na podstawie pomiarów sprawności oświetlenia różniły się maksymalnie o 3% od wartości obliczonych.

EN

In this paper, we present the analysis results of the influence of technical parameters of the examined indirect lighting installation on its utilization factor and lighting uniformity. Indirect lighting installations using LEDs were studied first through simulations and then through empirical measurement in a model. The utilization factor observed empirically in the model and obtained in computer simulations differed by only 3%.

8

Optical characterisation of vertical-external-cavity surface-emitting lasers (VECSELs)

75%

Wójcik-Jedlińska A. , Piersciński K. , Jasik A. , Muszalski J. , Bugajski M.

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tom Vol. 37, nr 4

449-457

EN

The purpose of this paper is to outline the principles of optical characterisation of the new kind of semiconductor devices: vertical-external-cavity surface-emitting lasers (VECSELs). Realisation of high efficiency semiconductor devices requires high accuracy of epitaxial process. Gain characteristic of VECSEL structure is strongly affected by the precise placing of the quantum wells within the multilayer structure. Detailed optical characterisation of particular parts of the structure allows growth errors to be identified and gives insight into the lasing behaviour. In this work, we present an approach taking advantage of two spectroscopic techniques, photoluminescence and reflectance measurements, to study properties of VECSEL structure based on InGaAs/GaAs active region, designed for emission wavelength at 980 nm.

9

Narrowband shortwave minima of multispectral reflectance as indication of algal blooms associated with the mesoscale variability in the Brazil-Malvinas Confluence

75%

Karabashev G. S. , Evdoshenko M. A.

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tom 60

|

nr 4

10

A polynomial approach for reflection, transmission, and ellipsometric parameters by isotropic stratified media

75%

El-Agez T. , Taya S. , El Tayyan A.

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tom Vol. 40, nr 2

501--510

EN

A polynomial approach for the calculation of the reflectance, the transmittance, and the ellipsometric parameters of a stratified isotropic planar structure is presented. We show that these parameters can be written in a very simple and compact form using the so-called elementary symmetric functions that are extensively used in the mathematical theory of polynomials. This approach is applied to quarter-wave Bragg reflectors. The numerical results reveal an exact match with the well known matrix formalism.

11

Wpływ właściwości odbiciowych podłoża, na którym zainstalowano daną oprawę oświetleniową na względną wartość zanieczyszczenia jej otoczenia światłem

75%

Tabaka P. , Fryc I.

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tom T. 21, cz. 2

137--144

PL

Artykuł zawiera wyniki badań dotyczących efektu zanieczyszczenia otoczenia światłem. Przeanalizowany został wpływ zastosowanego typu oprawy oświetleniowej oraz rodzaju podłoża, na którym jest ona zainstalowana, na względne wartości natężenia oświetlenia nad daną lampą. W rozważaniach uwzględniono typowe, stosowane w oświetleniu terenów zewnętrznych, oprawy oświetleniowe umiejscowione na podłożu typu: trawa, gleba, beton, asfalt i śnieg. Założono, że oprawy te emitują jednakowy strumień świetlny. Obliczenia przeprowadzono wykorzystując program komputerowego wspomagania projektowania oświetlenia DIALux. Wykazano, że stopień zanieczyszczenia światłem otoczenia zależny nie tylko od krzywej światłości oprawy oświetleniowej, ale także od właściwości odbiciowych podłoża na którym umiejscowiono tę lampę.

EN

The article contains the research results on light pollution relative values. The effect of used luminaire type was analyzed and the kind of ground on which the lamp was installed. Calculations were performed by using professional computer-aided lighting design software DIALux. A number of typical outdoor lighting fixtures were taken into account. These lamps were placed on a grass, soil, concrete, asphalt and snow ground. It was assumed that these luminaires emit the same value of luminous flux. It has been shown that the degree of light pollutions dependent not only on the intensity curve of given luminaire but also on the reflective properties of the ground under the lamp.

12

Atmospheric correction of APEX hyperspectral data

75%

Sterckx S. , Vreys K. , Biesemans J. , Iordache M.-D. , Bertels L. , Meuleman K.

Miscellanea Geographica. Regional Studies on Development

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2016

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tom 20

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nr 1

16-20

EN

Atmospheric correction plays a crucial role among the processing steps applied to remotely sensed hyperspectral data. Atmospheric correction comprises a group of procedures needed to remove atmospheric effects from observed spectra, i.e. the transformation from at-sensor radiances to at-surface radiances or reflectances. In this paper we present the different steps in the atmospheric correction process for APEX hyperspectral data as applied by the Central Data Processing Center (CDPC) at the Flemish Institute for Technological Research (VITO, Mol, Belgium). The MODerate resolution atmospheric TRANsmission program (MODTRAN) is used to determine the source of radiation and for applying the actual atmospheric correction. As part of the overall correction process, supporting algorithms are provided in order to derive MODTRAN configuration parameters and to account for specific effects, e.g. correction for adjacency effects, haze and shadow correction, and topographic BRDF correction. The methods and theory underlying these corrections and an example of an application are presented.

13

Spectral discrimination of arable from fallow fields as landscape components

75%

Piekarczyk J.

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nr 3

EN

Remote sensing methods, including aerial photography and satellite images, could be successfully used for detecting and acreage assessing of landscape components like fallow fields. The objective of the present study was to characterize the reflectance of fallow fields situated in various soil conditions and of different age and compare them with spectral characteristics of main arable crops: winter rye, spring oat, winter oilseed rape, corn, potatoes and meadow. Field spectral reflectance measurements were made with the CIMEL CE313 luminancemeter and five vegetation indices (NDVI, STVI, MSI, MNDVI and GRVI) were developed by combining the reflectance factors in the five wavebands (450, 550, 650, 850 and 1650 nm). In the second part of May, when seasonal biomass peak of winter crops and meadows occurs and spring crops partly covers the soil, significant differences were observed in the spectral properties of fallow and cultivated fields. Results showed that among the analyzed vegetation indices MSI index (R₁₆₅₀/ R₈₅₀) was found to be the best for discriminating among the fallow fields and GRVI (R₅₅₀/R₆₅₀) and NDVI ((R₈₅₀–R₆₅₀)/(R₈₅₀+R₆₅₀)), were the best discriminators between the fallow fields and arable crops.

14

Derivation of remote sensing reflectance of Baltic waters from above-surface measurements

75%

Olszewski J. , Darecki M.

Oceanologia

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1999

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tom 41

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nr 1

15

High-performance quasi one-dimensional mirrors of mechanical waves built of periodic and aperiodic structures

63%

Garus S. , Sochacki W.

Journal of Applied Mathematics and Computational Mechanics

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2018

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tom Vol. 17, nr 4

19--24

EN

The work studied the reflectance for quasi one-dimensional phononical structures. In composite superlattices, the thickness of the layers, their arrangement and selection of constituent materials with appropriate properties such as the density and velocity of mechanical waves propagation allows for the creation of a phononic band gap (PhBG) phenomenon. PhBG is characterized by high reflectance of the mechanical wave incident on the analyzed structure, which means that the wave does not propagate in the superlattice. The paper proposes periodic and aperiodic structures characterized by a wide range of reflectance for the ultrasonic frequencies of mechanical waves and shows how the change the thickness of the layer affects the properties of the analyzed structures.

16

Typy centrów paramagnetycznych a właściwości sprężyste i optyczne węgli kamiennych

63%

Pilawa B. , Pusz S. , Krzesińska M. , Kwiecińska B.

Karbo

|

2003

|

tom Nr 4

224-227

PL

Wyznaczono dynamiczny moduł sprężystości, zdolność odbicia światła oraz parametry widm elektronowego rezonansu paramagnetycznego (EPR) dla szerokiego zakresu węgli kamiennych (83,5-94,9 % mas. C). Celem pracy było znalezienie różnych grup centrów paramagnetycznych w badanych węglach kamiennych oraz porównanie właściwości centrów paramagnetycznych z właściwościami elastycznymi i optycznymi próbek. W badanych węglach kamiennych znaleziono trzy różne grupy centrów paramagnetycznych, odpowiedzialne za szerokie linie Gaussa ( AB : 0,87-0,98 mT, g: 2,0031 -2,0037), szerokie linie Lorentza l (AB : 0,43-0,54 mT, g: 2,0030-2,0035) oraz wąskie linie Lorentza 2 (DeltaBpp: 0,08-0,14 mT, g: 2,0029-2,0030). Koncentracje centrów paramagnetycznych odpowiedzialnych za szerokie linie EPR malej ą wraz ze wzrostem anizotropii sprężystej węgla kamiennego. Szerokości linii wszystkich rodzajów centrów paramagnetycznych maleją ze wzrostem gęstości rzeczywistej węgla kamiennego. Zaobserwowano spadek wartości współczynnika g szerokiej linii Gaussa i szerokiej linii Lorentza l wraz ze wzrostem zawartości pierwiastka C w węglu oraz wraz ze wzrostem średniej zdolności odbicia światła węgla.

EN

Dynamic elastic moduli, optical reflectance and electron paramagnetic resonance (EPR) spectra parameters were determined for a wide rank coals (83,5-94,9 wt % C). The aim of this work was to find different groups of paramagnetic centers in the studied coals and to compare the feature of the paramagnetic centers with elastic and optical properties of coal. Three different groups of paramagnetic centers with broad Gauss (Delta Bpp 0,87-0,98 mT, g: 2,0031 -2,0037), broad Lorentz 1 (DeltaB: 0,43-0,54 mT, g: 2,0030-2,0035), and narrow Lorentzian 2 (AB : 0,08-0,14 mT, g: 2,0029-2,0030) lines were found in the studied coals. Concentrations of paramagnetic centers responsible for broad EPR lines decrease with increasing elastic anisotropy of coal. Linewidths of all types of paramagnetic centers decrease with increase of coal density. Decrease of g factor of broad Gauss and broad Lorentz 1 lines with increasing both a carbon content and mean reflectance was observed. KURZEJA L., MUSZYŃSKI J., DUBER S., SZELUGA U.: New carbon nanotubes/polymer composites and their properties.

17

Wpływ sposobu utleniania na właściwości i strukturę węgli i litotypów

63%

Machnikowska H. , Łuczak A. , Kubacki A.

Karbo

|

2003

|

tom Nr 3

157-164

PL

W celu określenia wpływu rodzaju czynnika utleniającego i natury węgla na efekty utleniania przeprowadzono badania właściwości i struktury węgla gazowego i ortokoksowego oraz litotypów: witrynów z obu węgli i durynu z węgla gazowego utlenianych powietrzem oraz roztworami 32 % HNO3 i 30 % H2O2. Utlenianie powietrzem i kwasem powoduje znaczne zmiany składu elementarnego i zawartości grup funkcyjnych. W próbkach utlenionych zwiększa się znacznie stosunek atomowy O/C i zawartość tlenowych grup funkcyjnych, a zmniejsza się udział alifatycznych i aromatycznych grup C-H. Zakres zmian zależy od sposobu utleniania, stopnia uwęglenia i składu petrograficznego utlenianego węgla. Największy stopień utlenienia wykazuje witryn z węgla gazowego utleniony powietrzem, najmniejszy - duryn z węgla gazowego utleniany kwasem. Efekty utleniania powietrzem w większym stopniu zależą od składu petrograficznego niż efekty utleniania kwasem azotowym. Utleniane powietrzem powoduje znaczne zwiększenie średniej reflek-syjności witrynitów wskazujące na wzrost aromatyczności struktury. Wzrost refleksyjności jest większy dla witrynitu wyżej uwęglonego. Utlenianie kwasem azotowym obniża refleksyjność witrynitów o taką samą wartość, niezależnie od stopnia uwęglenia.

EN

Gas coal and orthocoking coal and separated lithotypes (vitrains and gas coal durain) were oxidized with various media to study the effect of reagent and coal nature on the properties and structure of resultant pro- e ducts. The treatments included the reactions with air at 200°C for 24 h and with nitric acid (32 %) and hydrogen peroxide (30 %) at 80°C for 2h. >r Oxidation with air and HNO3 induces meaningful and differentiated changes in the elemental composition and functional group contents. A considerable increase in the O/C atomic ratio and oxygen group contribution v is accompanied with a reduction of proportions of aliphatic and aromatic C-H groups. The extent of alteration decreases from the air-oxidized gas -' coal vitrain to the acid-oxidized gas coal durain. The petrographic composition is more relevant in the case of air than nitric acid oxidation. At comparable reaction conditions, the hydrogen peroxide is less efficient '' oxidizing agent than nitric acid. The variation of mean reflectance indica- '' tes an essential modification of macromolecular structure to occur as a result of air and nitric acid oxidation. The character of changes depends ; on the oxidation agent. A considerable increase in the mean reflectance of l vitrinites occurring on air oxidation can be related to the enhanced aroma-ticity of the structure. The effect is more pronounced for a higher rank vitrinite. Nitric acid oxidation reduces the reflectance in the extent being independent on rank. Wide distributions of the measured reflectance values indicate a big heterogeneity of oxidized vitrinites. The mean reflectance and reflectance ranges suggest that air and acid oxidized vitrinites, which show rather similar elemental composition and functional groups content, differ each other essentially in terms of aromatic unit size.

18

Anizotropia sprężysta i optyczna koksów uzyskanych w laboratoryjnej skali

63%

Krzesińska M. , Pusz S. , Koszorek A.

Karbo

|

2003

|

tom Nr 4

218-223

PL

Wykonano badania zależności kierunkowych właściwości sprężystych i optycznych koksów wytworzonych w warunkach laboratoryjnych z pojedynczych węgli wyjściowych o zróżnicowanych właściwościach kokso- twórczych. Do koksowania w laboratoryjnej retorcie Jenknera użyto 15 różnych węgli typów od 33 do 37, różniących się indeksem Rogi (RI) w zakresie od O do 76. Stwierdzono, że tak uzyskane koksy wykazują zróżnicowane właściwości kierunkowe badanych parametrów i pod tym względem można je podzielić na dwie grupy. Zaobserwowane różnice wynikają prawdopodobnie z odmiennej budowy ciągłej matrycy i innego kształtu porów.

EN

Dynamic elastic moduli, optical reflectance and electron paramagnetic resonance (EPR) spectra parameters were determined for a wide rank coals (83,5-94,9 wt % C). The aim of this work was to find different groups of paramagnetic centers in the studied coals and to compare the feature of the paramagnetic centers with elastic and optical properties of coal. Three different groups of paramagnetic centers with broad Gauss (ABp • 0,87-0,98 mT, g: 2,0031 -2,0037), broad Lorentz 1 (AB : 0,43-0,54 mT, g: 2,0030-2,0035), and narrow Lorentzian 2 (AB : 0,08-0,14 mT, g: 2,0029-2,0030) lines were found in the studied coals. Concentrations of paramagnetic centers responsible for broad EPR lines decrease with increasing elastic anisotropy of coal. Linewidths of all types of paramagnetic centers decrease with increase of coal density. Decrease of g factor of broad Gauss and broad Lorentz 1 lines with increasing both a carbon content and mean reflectance was observed.

19

Resolution in the 3D modeling of objects for additive manufacturing and reverse engineering – shutter effect

63%

Coutiño-Moreno E. , Estrada Q. , Maldonado-Onofre D. , Rodriguez-Mendez A. , Gomez-Giron J.

Applied Computer Science

|

2021

|

tom Vol. 17, no 1

40--52

EN

This article presents a proportional relationship between Shutter and the value of the resolution scanning system that allows decision making for modeling 3D parts used in reverse engineering and additive manufacturing. As a first step, the object of interest is treated to dim excessive brightness, then the object is scanned (by point cloud or mesh) with the use of a Handyscan 700 scanner. The point cloud is processed with the Geomagic software Desing X to generate a CAD image and a “.stl” file for 3D printing.

20

Ocena przydatności farby przewidzianej do pomalowania wnętrza kuli ulbrichta

63%

Tabaka P.

Prace Instytutu Elektrotechniki

|

2012

|

tom Z. 256

87-99

PL

W fotometrii do pomiarów strumienia świetlnego używa się lumenomierzy przestrzennych, które zwykle mają kształt kuli pomalowanej od wewnątrz białą farbą. Farba ta musi spełniać wymagania norm i przepisów. W publikacji przedstawiono ogólne wymagania stawiane wewnętrznym pokryciom lumenomierzy kulistych, wynikające z teorii pomiaru strumienia świetlnego w lumenomierzu. Zaprezentowano także wyniki przeprowadzonych badań w odniesieniu do jednej próbki pokrytej białą farbą, pod kątem określenia jej przydatności do pomalowania kuli Ulbrichta. Zmierzono całkowity współczynnik odbicia, rozsył światłości światła odbitego, krzywe rozkładów widmowych światła padającego i odbitego. Sprawdzono także stopień zniekształcenia kolorymetrycznego lumenomierza po regeneracji jego wnętrza.

EN

In photometry, in order to measure luminous stream, photometric integrators are used. They are usually spherical in shape and their interior is covered with white paint. The paint must meet requirements of norms and standards. This paper deals with general requirements which must be met in case of covering the inside of photometric integrators. The requirements are related to the theory of luminous stream measurement in a photometric integrator. This paper additionally presents results of research in terms of one sample chich was covered with white paint and its suitability for covering the insi de of Ulbricht's sphere. Total reflection coefficient as well as luminous propagation of reflected light and spectral distribution curve have been measured. The degree of integrator's colorimetric distortion after recovery of its inside has been checked.