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LP-MOVPE growth and properties of high Si-doped InGaAs contact layer for quantum cascade laser applications

Ściana B., Badura M., Dawidowski W., Bielak K., Radziewicz D., Pucicki D., Szyszka A., Żelazna K., Tłaczała M.

Opto-Electronics Review

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2016

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Vol. 24, No. 2

95--102

EN

The work presents doping characteristics and properties of high Si-doped InGaAs epilayers lattice-matched to InP grown by low pressure metal-organic vapour phase epitaxy. Silane and disilane were used as dopant sources. The main task of investigations was to obtain heavily doped InGaAs epilayers suitable for usage as plasmon-confinement layers in the construction of mid-infrared InAlAs/InGaAs/InP quantum-cascade lasers (QCLs). It requires the doping concentration of 1×10¹⁹ cm⁻³ and 1×10²⁰ cm⁻³ for lasers working at 9 μm and 5 μm, respectively. The electron concentration increases linearly with the ratio of gas-phase molar fraction of the dopant to III group sources (IV/III). The highest electron concentrations suitable for InGaAs plasmon-contact layers of QCL was achieved only for disilane. We also observed a slight influence of the ratio of gas-phase molar fraction of V to III group sources (V/III) on the doping efficiency. Structural measurements using high-resolution X-ray diffraction revealed a distinct influence of the doping concentration on InGaAs composition what caused a lattice mismatch in the range of –240 ÷ –780 ppm for the samples doped by silane and disilane. It has to be taken into account during the growth of InGaAs contact layers to avoid internal stresses in QCL epitaxial structures.

2

Technology and properties of low-pressure metalorganic vapour phase epitaxy grown InGaAs/AlInAs superlattice for quantum cascade laser applications

Badura M., Bielak K., Ściana B., Radziewicz D., Pucicki D., Dawidowski W., Żelazna K., Kudrawiec R., Tłaczała M.

Optica Applicata

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2016

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Vol. 46, nr 2

241--248

EN

Quantum cascade laser is one of the most sophisticated semiconductor devices. The active region of the quantum cascade laser consists of hundreds thin layers, thus the deposition precision is the most crucial. The main technique for the fabrication of quantum cascade laser structure is molecular beam epitaxy, however, the prevalence of metalorganic vapour phase epitaxy techniques in the fabrication of semiconductor structures causes a perpetual work on the improvement production of the entire quantum cascade laser structure by the metalorganic vapour phase epitaxy. The paper presents technological aspects connected with the metalorganic vapour phase epitaxy growth of InGaAs/AlInAs low-dimensional structures for quantum cascade laser active region emitting ~9.6 μm radiation. Epitaxial growth of superlattice made of InGaAs/AlInAs lattice matched to InP was conducted at the AIXTRON 3x2″ FT system. Optical and structural properties of such heterostructures were characterised by means of high resolution X-ray diffraction, photoluminescence, contactless electroreflectance and scanning electron microscope techniques. Epitaxial growth and possible solutions of structure improvements are discussed.

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Biochar from a digestate as an energy product and soil improver

Radawiec W., Dubicki M., Karwowska A., Żelazna K., Gołaszewski J.

Agricultural Engineering

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2014

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Vol. 18, No. 3

149--156

EN

Digestate, as bio-degradable agricultural biogas waste may be subject to the direct management as a fertilizer or, after separation of the solid and liquid phase – solid phase may be subjected to thermo-chemical transformation to biochar. Biochar is a carbonization product with high carbon concentration and relatively low decomposition susceptibility, obtained from various types of organic waste (International Biochar Initiative). Biomas carbonization takes place in the torrefaction process in the temperature from 200ºC to 320ºC. The chemical composition and utility properties of biochar depend on the substrate type and the process parameters. Biochar obtained from biodegradable waste may be an element of carbon biosequestration and used as biofuel, whereas in agriculture – as soil improver, which decomposes for a long time and which positively influences soil fertility, number of biogenic components and physical and water properties. The paper presents characteristic of the torrefaction process, process products and utility values of biochar from the point of view of energy and the agricultural value.

PL

Masa pofermentacyjna, jako biodegradowalny odpad biogazowni rolniczej może podlegać zagospodarowaniu bezpośredniemu jako nawóz lub też, po separacji fazy stałej i ciekłej – faza stała może być poddana termochemicznej transformacji do biowęgla. Biowęgiel jest karbonizatem o wysokiej koncentracji węgla i względnie małej podatności na rozkład, pozyskany z różnego rodzaju odpadów organicznych (International Biochar Initiative). Uwęglenie biomasy następuje w procesie toryfikacji w temperaturze od 200ºC do 320ºC. Skład chemiczny oraz właściwości użytkowe biowęgla uzależnione są od rodzaju substratu oraz parametrów procesu. Pozyskiwany z odpadów biodegradowalnych może być elementem biosekwestracji węgla i wykorzystany jako biopaliwo, zaś w rolnictwie – jako długo rozkładający się polepszacz gleby pozytywnie wpływający na żyzność gleby, zasobność w składniki biogenne oraz właściwości fizyczne i wodne. W pracy przedstawiono charakterystykę procesu toryfikacji, produkty procesu oraz walory użytkowe biowęgla z punktu widzenia wartości energetycznej i rolniczej.

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Assessment of mutagenic activity of methyl- and phenylphenanthrenes based on Salmonella test and micronucleus test

Rudnicka K., Tejs S., Budzikur K. A., Mielżyńska-Švach D., Jakimiuk E., Chachaj A., Góra M., Żelazna K., Łuczyński M. K.

Environmental Biotechnology

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2013

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Vol. 9, No. 2

65--71

EN

Polycyclic aromatic hydrocarbons (PAHs) are widely spread environmental pollutants mainly originating from anthropogenic sources such as fossil fuel combustion, industries, and others. Although a large body of literature exists on the toxicity and carcinogenicity of PAHs, primarily benzo[a]pyrene, toxicity data for phenanthrene deriveratives are very limited. The main aim of the experiment was to investigate if there exists correlation between molecular structure and mutagenic activity of four phenanthrene derivatives: 1 methylphenanthrene, 4 methylphenanthrene, 1 phenylphenanthrene, and 4 phenylphenanthrene. An Ames assay using two strains of histidine dependent Salmonella Typhimurium (TA98 and TA100) was conducted to assess the mutagenic activity of studied compounds both in the presence (+S9) and in the absence (-S9) of an exogenous source of metabolic activation. The compounds were also tested in an in vitro chromosome aberration assay in which V-79 cells were exposed to the phenanthrene derivatives investigated both in the presence and in the absence of metabolic activation. The phenylphenanthrenes showed no mutagenic effect. These compounds occasionally induced significant decrease in the number of revertants in the Ames test. The greatest mutagenic effects were observed for 1 methylphenanthrene after metabolic activation (+S9). In the micronucleus test the greatest mutagenic effect was observed for 4 methylphenanthrene also in the presence of metabolic activation system. The results obtained are comparable to those reported earlier for the methylphenanthrenes.

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Conceptual framework of bioethanol production from lignocellulose for agricultural profitability

Gołaszewski J., Żelazna K., Karwowska A., Olba-Zięty E.

Environmental Biotechnology

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2012

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Vol. 8, No. 1

15-27

EN

Among currently developed biofuel and green-power technologies, technological development of lignocellulose biomass-based production of ethanol will be particularly important in a short time perspective as those specific activities constitute an intermediary stage in the process of developing integrated processes of biomass conversion in the route to the universal energy carrier - hydrogen or electricity. Agricultural biorefinery or agri-refinery which converts agricultural biomass to a wide spectrum of biofuels and bioproducts is considered as the key element of the future economy. The biorefinery which produces biofuels and generates bioenergy will constitute the so called agri-energy complex - a local power unit implemented in the system of dispersed energy generation. It is worth noticing that agri-refinery will integrate three fundamental drivers of sustainable development of rural areas - bioeconomics, environment and society. This paper aims at elaborating the conceptual framework of the agri-refinery in the aspect of conversion of agricultural lignocellulosic biomass into bioethanol and other bioproducts as well as the future economy and sustainable development.

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In vitro micronucleus test assessment of polycyclic aromatic hydrocarbons

Żelazna K., Rudnicka K., Tejs S.

Environmental Biotechnology

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2011

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Vol. 7, No. 2

70-80

EN

Polycyclic aromatic hydrocarbons (PAH) can be dangerous due to their genotoxic properties and the formation of DNA adducts in the target organs. The increasing number of environmental pollutants containing polycyclic aromatic compounds requires the use of inexpensive and relatively quick assays enabling evaluation of potential genotoxicity of chemicals. Therefore, the in vitro micronucleus assay (MN) has been developed as a rapid screening test based on measuring and counting the micronuclei in various cells subjected to the examined compound. Combined with the cytokinesis-block micronucleus (CBMN) technique and the fluorescence in situ hybridization (FISH) assay, it also enables classification of compound mutagenic activity into aneugenic or clastogenic categories, the identification of the mechanism of MNi formation and the estimation of malsegregations of chromosomes amongst the two nuclei in binucleated cells. The combination of these different approaches is very useful in performing risk assessments of PAH with threshold types of dose responses.

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Mleko i produkty mleczarskie w żywieniu człowieka

Żelazna K., Popieralska A.

Przemysł Spożywczy

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2003

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T. 57, nr 10

26-31

PL

Artykuł przedstawia wartość odżywczą, dietetyczną i energetyczną mleka oraz produktów mlecznych; ich właściwości, sposoby wykorzystania i zalecenia w żywieniu człowieka. Omówiono rolę wybranych składników mleka i jego przetworów, takich jak: wapń, fosfor, magnez, potas, cynk, białko, tłuszcz, laktoza i witaminy. Mleczne napoje fermentowane zaprezentowano jako żywność funkcjonalną.

EN

The article presents nutritionally, dietetically and energetically values of milk and milk products; their attributes, ways of use and recommendations in human diet. The paper discusses the role of chosen elements of milk and milk products, as: calcium, phosphorus, magnesium, potassium, zinc, protein, far, lactose and vitamins. Fermented milk drinks are presented as functional food.