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Wyniki wyszukiwania dla: CHEMICAL SYNTHESIS
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Chemical and thermal stability of core-shelled magnetite nanoparticles and solid silica
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Preliminary studies of the chemical composition and cytotoxic activity of Hottonia palustris herb
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Application of electrochemical sensors and sensor matrixes for measurement of odorous chemical compounds
PublikacjaIn this paper describes the principle of operation of the electrochemical sensors and the sensor matrixes comprised of electrochemical sensors intended for measurement of odorous compounds. Critical comparison of these sensors’ advantages and disadvantages has been made. The fields of economy contributing to release of odours and the potential sources of their emission have been identified. Commercially available electrochemical...
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Tuning the ferromagnetic phase in the CDW compound SmNiC2 via chemical alloying
PublikacjaWe report a study on tuning the charge density wave (CDW) ferromagnet SmNiC2 to a weakly coupled superconductor by substituting La for Sm. X-ray diffraction measurements show that the doped compounds obey Vegard’s law, where La (Lu) alloying expands (shrinks) the lattice due to its larger (smaller) atomic size than Sm. In the series Sm1−xLaxNiC2, CDW transition (TCDW =148K) for SmNiC2 is gradually suppressed, while the ferromagnetic...
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Chemical Aspects of Biological Activity of Isothiocyanates and Indoles, the Products of Glucosinolate Decomposition
PublikacjaThere is growing evidence that cancer chemoprevention employing natural, bioactive compounds may halt or at least slow down the different stages of carcinogenesis. A particularly advantageous effect is attributed to derivatives of sulfur-organic phytochemicals, such as glucosinolates (GLs) synthesized mainly in Brassicaceae plant family. GLs are hydrolysed enzymatically to bioactive isothiocyanates (ITC) and indoles, which exhibit strong...
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Recent Progress on Hydrogen Storage and Production Using Chemical Hydrogen Carriers
PublikacjaDepleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new, sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However, the limiting issue for large-scale commercialization of hydrogen technologies is a safe, efficient, and economical method of gas storage. In industrial practice,...
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Chemical Vapor Transport Route toward Black Phosphorus Nanobelts and Nanoribbons
PublikacjaChemical vapor transport (CVT) method is widely used for bulk black phosphorus (BP) fabrication. In this work, we demonstrate that CVT provides a route for the fabrication of BP nanoribbons and nanobelts. This method consists of a two-step procedure, including initial BP column growth using the CVT technique, followed by ultrasonic treatment and centrifugation. The obtained nanostructures preserve BP column dimensions, forming...
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Chemical analysis of low carbon content coals and their applications as dye adsorbent
PublikacjaCoal is primarily a fuel material but lately it has been utilized as an adsorbent for removing toxic metal ions. However, its usage for removing organic pollutants is not well studied. We report here a systematic study on the use of coal samples of varying carbon contents as adsorbents for removing Basic Blue 41 as a model cationic dye. The coal samples were collected from coal mines and were thoroughly characterized. The concentrations...
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ELECTRICAL CONDUCTIVITY AND pH IN SURFACE WATER AS TOOL FOR IDENTIFICATION OF CHEMICAL DIVERSITY
PublikacjaIn the present study, the creeks and lakes located at the western shore of Admiralty Bay were analysed. The impact of various sources of water supply was considered, based on the parameters of temperature, pH and specific electrolytic conductivity (SEC25). All measurements were conducted during a field campaign in January-February 2017. A multivariate dataset was also created and a biplot of SEC25 and pH of the investigated waters...
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A Molecular dynamics study of the influence of chemical reduction on the structure of amorphous germania
PublikacjaPraca poświęcona jest badaniom struktury blisko- i średniozasięgowej redukowanego amorficznego tlenku germanu o składzie 1Ge 1GeO2 za pomocą symulacji dynamiczno-molekularnych. Symulacje MD realizowano w zespole mikrokanonicznym (NVE), z wykorzystaniem dwuciałowego potencjału oddziaływania miedzyatomowego Borna-Mayera-Hugginsa. Wyraźnie widoczna tendencja do aglomeracji neutralnych atomów Ge została porównana z tendencją do aglomeracji...
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A Chemical Recognition Element for Lithium Ions Based on Optical Electronic Absorption.
PublikacjaOtrzymano próbki kserożeli techniką zol-żel. Otrzymane materiały zastosowano do konstrukcji czujników optycznych. Rolę elementu rozpoznającego w uzyskanych próbkach pełnią chromogeniczne etery koronowe zawierające w makro pierścieniu dwie grupy azowe oraz resztę fenolu. W obecności soli metali I grupy układ u okresowego obserwowano zmiany w widmach absorpcyjnych. Dla matrycy zawierającej jako materiał czujnikowy 21-członową...
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Biological fluids as a source of information on the exposure of man to envinonmental chemical agents.
PublikacjaWiele związków (min. lotne związki chlorowcoorganiczne, metale) ma szkodliwy wpływ na tkanki i narządy organizmu ludzkiego, wywołując nieodwracalne zmiany chorobowe. W celu określenia zagrożenia zawodowego coraz częściej wykonuje się pomiar stężeń substancji chemicznych i ich metabolitów w płynach biologicznych - moczu, krwi, rzadziej w mleku matki, żółci, ślinie, czy też spermie. Aby oznaczyć poziomy tych stężeń, pobrane próbki...
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Investigations of dissimilar stainless steels welded joints for chemical tankers construction
PublikacjaArtykuł przedstawia właściwości mechaniczne złączy różnoimiennych stali typu duplex oraz austenitycznej typu 316L otrzymanych za pomocą spawania automatycznego łukiem krytym. Wykazano możliwość wykorzystania wysokowydajnej metody SAW w miejsce dotychczas stosowanych metod GTAW i GMAW do spawania blach zbiorników statków do przewozu chemikaliów.
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Electrode materials for electrochemical capacitors based on poly(3,4-ethylenedioxythiophene) and functionalized multi-walled carbon nanotubes characterized in aqueous and aprotic electrolytes
PublikacjaWithin this work, we report a facile one-stage synthesis of nanocomposites based on functionalized carbon nanotubes (CNTs) and electroactive polymer poly(3,4-ethylenedioxythiophene). Three different composites are investigated as potential electrode materials for the electrochemical capacitors. Two of the composites contain carbon nanotubes (ox-CNTs), functionalized by acid oxidation process (65% HNO3, 120 °C). The third composite...
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Development of Microstructured Carbon Coatings by Substrate-Catalytic CVD
PublikacjaCarbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H2/CH4/N2 gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between the steel and carbonaceous layer. The carbon films exhibited wall-like and spherical morphologies and structures, as characterized by scanning electron microscopy and Raman...
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Meiothermus ruber cells as β-galactosidase activity biocatalyst
PublikacjaThe current study allowed to establish the possibility of using whole cells of thermophilic bacteria Meiothermus ruber as a biocatalyst with β-galactosidase activity. β-galactosidases are used for hydrolysis of lactose as well as for oligosaccharides synthesis. The advantages of using whole bacterial cells catalysis is not only elimination of tedious, expensive protein isolation and/or purification but also stabilization of enzymes...
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Investigation of H2:CH4 plasma composition by means of spatially resolved optical spectroscopy
PublikacjaThe system based on spatially resolved optical emission spectroscopy dedicated for in situ diagnostics of plasma assisted CVD processes is presented in this paper. Measurement system coupled with chemical vapour deposition chamber by dedicated fiber-optic paths enables investigation of spatial distribution of species densities (Hx, H+, CH, CH+) during chemical vapour deposition process. Experiments were performed for a various...
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A novel methodology for the enantiomeric resolution of methamphetamine, its precursors and intermediates by GC-MS
PublikacjaImpurity profiling and classification of abused drugs using chiral analytical techniques is of particular interest and importance because of the additional information obtained from this approach. When these methods are applied to the synthesis of illicitly used substances, they can supply valuable information about the conditions/chemicals used in the synthesis. In this study, simultaneous chiral separation of methylamphetamine,...
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Environmental impact and industrial development of biorenewable resources for polyurethanes
PublikacjaPolyurethanes are among the most developed types of polymers. They are produced from the three primary components, i.e., polyols, low-molecular-weight glycols used as chain extenders, and diisocyanates. Until recently, all these substrates have been obtained via petrochemical processes. A decrease in petroleum-based resources and new ecological trends in chemistry, chemical technology, and materials engineering have generated increasing...
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Chemometric exploration of sea water chemical component data sets with missing elements
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Morphologic, Phylogenetic and Chemical Characterization of a Brackish Colonial Picocyanobacterium (Coelosphaeriaceae) with Bioactive Properties
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Solvent effects on the nitrogen NMR chemical shifts in 1-methylazoles – a theoretical study
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Theoretical analysis of solvent effects on nitrogen NMR chemical shifts in oxazoles and oxadiazoles
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Physical, chemical and biochemical properties of Western Siberia Sphagnum and Carex peat soils
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Chemical Munitions Search & Assessment—An evaluation of the dumped munitions problem in the Baltic Sea
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Consequences of New Approach of Chemical Stability Tests of Active Pharmaceutical Ingredients (APIs)
PublikacjaThere is a great need of broaden look on stability tests of active pharmaceuticalingredients (APIs) in comparison with current requirements contained in pharmacopeia.By usage of many modern analytical methods the conception of monitoring the changesof APIs during initial stage of their exposure to harmful factors has been developed. Newknowledge must be acquired in terms of identification of each degradation...
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Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites
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Identification of Novel Chemical Scaffolds Inhibiting Trypanothione Synthetase from Pathogenic Trypanosomatids
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Scaffolds Loaded with Dialdehyde Chitosan and Collagen—Their Physico-Chemical Properties and Biological Assessment
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Chemical, thermal and laser processes in recycling of photovoltaic silicon solar cells and modules
PublikacjaIn recent years, photovoltaic power generation systems have been gaining unprecedented attention as an environmentally beneficial method to solve the energy problem. From the economic point of view the pure silicon, which can be recapture from the used cells, is the most important material due to its cost and shortage. In the paper selected methods of used or damaged module and cells recycling and experimental results are presented....
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Determination of the chemical structure of potencial organic impurities occuring in the drug substance opopramol
PublikacjaThe tricyclic antipsychotic and antidepressant drug opipramol was examined with regard to the chemical structure of its organic impurities. Impurities were isolated from the technical product by chromatographic methods and their chemical structures were estabilished by HMNR, MS and FTIR.
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Optical and chemical characterization of thin TiNx films deposited by DC-magnetron sputtering
PublikacjaThin titanium nitride (tinx) films were deposited on silicon substrates by means of a reactive dc-magnetron plasma. Layers were synthesized under various conditions of discharge power and nitrogen flows in two operation modes of the magnetron (the so-called "balanced" and "unbalanced" modes). The optical constants of the tinx films were investigated by spectroscopic ellipsometry (se). X-ray photoelectron spectroscopy (xps) was...
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Characteristics, Chemical Modification Processes as well as the Application of Silica and its Modified Forms
PublikacjaThe variety of chemical modifications of the surface of silica and its modified forms cause thesematerials to find a consistently wider scope of application. In the publication, the characteristicsof silica, silica gel, aerogel and xerogel are presented. The obtainment, application and propertiesof these materials are discussed. Methods of chemical modifications of surface structures withthe use of different chemical compounds...
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Chemical modification of tannins from Acacia mearnsii to produce formaldehyde free flocculant
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A Comprehensive Review on Shilajit: What We Know about Its Chemical Composition
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Preparation and characterization of silk fibroin/collagen sponge modified by chemical cross-linking
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INFLUENCE OF THE INTERMOLECULAR INTERACTION ON PHYSICO-CHEMICAL PROPERTIES OF CHITOSAN/HYALURONIC ACID BLENDS
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The Effects of Cross-Link Density and Chemical Exchange on Magnetization Transfer in Polyacrylamide Gels
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The Use of Chemical Sensors to Monitor Odour Emissions at Municipal Waste Biogas Plants
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Uncertainty in maritime risk analysis: Extended case study on chemical tanker collisions
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Effect of chemical composition and microstructure on mechanical properties of BA1055 bronze sand castings.
PublikacjaW pracy wykazano, że nawet małe zmiany w składzie chemicznym brązu aluminiowego BA1055 mają istotny wpływ na strukturę i właściwości mechaniczne odlewów. Określono wpływ wydzieleń międzymetalicznej fazy κ na właściwości odlewów z brązu BA1055 stosowanego na pędniki okrętowe.
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The Impact of Effective Microorganisms on Flesh Color and Chemical Composition of Raw Potato Tubers
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Influence of Hydrogenation on Morphology, Chemical Structure and Photocatalytic Efficiency of Graphitic Carbon Nitride
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Thermodynamics of Chemical Processes in the System of Nanocrystalline Iron–Ammonia–Hydrogen at 350 °C
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Phytoplankton communities of polar regions–Diversity depending on environmental conditions and chemical anthropopressure
PublikacjaThe polar regions (Arctic and Antarctic) constitute up to 14% of the biosphere and offer some of the coldest and most arid Earth's environments. Nevertheless several oxygenic phototrophs including some higher plants, mosses, lichens, various algal groups and cyanobacteria, survive that harsh climate and create the base of the trophic relationships in fragile ecosystems of polar environments. Ecosystems in polar regions are characterized...
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Chapter 11 – Application of Chemical Sensors and Sensor Matrixes to Air Quality Evaluation
PublikacjaIndoor and outdoor air quality is one of the key factors influencing human health. However, air quality evaluation is not easy task. Air is a complex system, which is subjected to changes even within short period of time. Progress in analytical methods and analytical tools provides increasingly more reliable information on the condition and quality of indoor and outdoor air. This progress, however, generates an increase in the...
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Study of Phase and Chemical Composition of Bi1-xNdxFeO3 Powders Derived by Pressureless Sintering
PublikacjaIn the present paper studies on Bi1xNdxFeO3 for x =0.1-0.4 are reported. The mixed oxide method followed with pressureless sintering was employed for ceramics fabrication. Thermal behavior of stoichiometric mixtures of simple oxide powders, viz. Bi2O3, Nd2O3 and Fe2O3 was studied by simultaneous thermal analysis. It was found that with an increase in neodymium content the weight loss increased from 0.75% to 3.16% for x =0.1 and...
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Raman Spectra Measurements for Chemical Identifications - Aspect of Uncertainty Sources and Reduction of Their Effects
PublikacjaRaman spectrometers enable fast and non-contact identification of examined chemicals. These devices measure Raman spectra and compare with the spectra database to identify unknown and often illicit chemicals (e.g. drugs, explosives) usually without any sample preparation. Raman spectra measurements are a challenge due to noise and interferences present outside the laboratories (field applications). The design of a portable Raman...
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TEST METHOD FOR DETERMINING THE CHEMICAL EMISSIONS OF A MARINE DIESEL ENGINE EXHAUST IN OPERATION
PublikacjaThe article briefly describes the problem of air pollution caused by sea-going ships and the resulting restrictions on the emission of toxic and harmful chemical compounds in the exhaust of marine engines, introduced by the International Maritime Organization (IMO) under the International Convention for the Prevention of Sea Pollution from Ships (MARPOL 73/78). Such emissions provide a significant metrological problem, not only...
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Crystal structure, chemical bonding, and physical properties of layered AIrSn2 (A = Sr and Ba)
PublikacjaWe report the experimental and theoretical investigation of structure, chemical bonding interactions, and physical properties of new ternary stannides AIrSn2 (A = Sr and Ba). AIrSn2 (A = Sr and Ba) crystallizes in the orthorhombic Re3B-type structure with the space group Cmcm (No. 64). According to single-crystal X-ray diffraction results, the structure of AIrSn2 (A = Sr and Ba) can be considered as a Zintl-type compound with heterogeneous...