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511.
Aleksandra Jankowska Agata Chopek Andrzej Kowalczyk Magorzata Rutkowska Marek Michalik Shiquan Liu Lucjan Chmielarz 《Molecules (Basel, Switzerland)》2020,25(23)
Spherical MCM-41 with various copper and iron loadings was prepared by surfactant directed co-condensation method. The obtained samples were characterized with respect to their structure (X-ray diffraction, XRD), texture (N2 sorption), morphology (scanning electron microscopy, SEM), chemical composition (inductively coupled plasma optical emission spectrometry, ICP-OES), surface acidity (temperature programmed desorption of ammonia, NH3-TPD), form, and aggregation of iron and copper species (diffuse reflectance UV-Vis spectroscopy, UV-Vis DRS) as well as their reducibility (temperature programmed reduction with hydrogen, H2-TPR). The spherical MCM-41 samples modified with transition metals were tested as catalysts of selective catalytic reduction of NO with ammonia (NH3-SCR). Copper containing catalysts presented high catalytic activity at low-temperature NH3-SCR with a very high selectivity to nitrogen, which is desired reaction products. Similar results were obtained for iron containing catalysts, however in this case the loadings and forms of iron incorporated into silica samples very strongly influenced catalytic performance of the studied samples. The efficiency of the NH3-SCR process at higher temperatures was significantly limited by the side reaction of direct ammonia oxidation. The reactivity of ammonia molecules chemisorbed on the catalysts surface in NO reduction (NH3-SCR) and their selective oxidation (NH3-SCO) was verified by temperature-programmed surface reactions. 相似文献
512.
Martyna Baca Agata Kryj Elahe Naghdi Pierre Gelin Sertan Sukas Priya Laha Herman Terryn Heidi Ottevaere Wim De Malsche 《Electrophoresis》2020,41(15):1287-1295
In the present study, cylindrical and laterally elongated pillar array columns were investigated for use in capillary electrochromatography. Minimal theoretical plate heights of H = 1.90 and 1.46 μm (in absence of sidewall effect) were obtained for coumarin C440 under unretained conditions for cylindrical and rectangular (laterally elongated, aspect ratio 4) pillar array columns, respectively. By comparing dispersion at the entire channel width to that at the central zone only, it appears that sidewall related dispersion significantly contributes to overall dispersion. A 40% reduction of the plate height was observed by taking into account only the central channel zone. A kinetic plot analysis was performed to evaluate the potential of the studied geometries by considering a maximum operating voltage of 20 kV as limiting parameter. It was demonstrated that rectangular radially elongated pillars produce a higher efficiency than cylindrical pillars and other microfabricated column structures for microchip capillary electrochromatography previously studied. 相似文献
513.
Giardina Agata Schiorlin Milko Marotta Ester Paradisi Cristina 《Plasma Chemistry and Plasma Processing》2020,40(4):1091-1107
Plasma Chemistry and Plasma Processing - Atmospheric pressure mass spectrometry (APCI-MS) was used to investigate the positive ions in air containing acetone (A), methanol (M) and mixtures thereof... 相似文献
514.
Agata Bojarska Lucja Marona Robert Czernecki Alexandr Khachapuridze Tadek Suski Piotr Perlin Igor V. Smetanin 《Journal of Russian Laser Research》2014,35(5):447-456
We demonstrate lasing emission of optically excited InGaN LD structures without intentional resonant cavity formation. We observe the equal mode-spacing character of this effect in the back-scattering geometry after exceeding the threshold excitation intensity. The homogeneity of the effect and stable mode spacing exclude participation of defects or wafer edges in lasing. We propose a lasing mechanism based on optically excited 2D electron–hole plasma oscillations, which act as a dynamical grating and resonantly couple the lasing modes separated by the plasma frequency, similar to the case of DFB lasers. The observed anomalous mode spacing is determined by the eigenfrequency of the plasma oscillations. 相似文献
515.
Agata Jasik Maciej Dems Paweł Wnuk Piotr Wasylczyk Anna Wójcik-Jedlińska Kazimierz Regiński Łukasz Zinkiewicz Krzysztof Hejduk 《Applied physics. B, Lasers and optics》2014,116(1):141-146
We report on the development of semiconductor double-chirped mirrors with the group delay dispersion of ?3,800 ± 100 fs2 in the wavelength range between 1,058 ÷ 1,064 nm and reflectivity of 99.1 %. The simplified plane-wave reflection transfer method was used to design the mirror multilayer stack. The mirror contains an epitaxial AlAs/GaAs structure topped with a SiNx antireflective layer. 相似文献
516.
517.
Agata Roguska Sachiko Hiromoto Akiko YamamotoMicha? Jerzy Wo?niak Marcin Pisarek Ma?gorzata Lewandowska 《Applied Surface Science》2011,257(11):5037-5045
Collagen fibril/(calcium phosphate and carbonate) composite coatings on 316L stainless steel were developed with a cathodic deposition technique. The response of SaOS-2 osteoblast-like cells to the collagen/calcium salt-coated 316L steel was investigated. The collagen fibrils were self-assembled on the 316L steel surface and immobilized by their partial incorporation into a calcium salt layer electrodeposited cathodically in Hanks’ solution. The amount of calcium salt depended on the applied cathodic potential. The mineralization of collagen fibrils was observed. The collagen coverage localized and the composition of calcium salts varied on the same specimen. Such non-uniform surfaces affected the cell response. The observed outlines of cell bodies and nuclei on the thin collagen coating were clearer than those on the thick collagen coating in most cases. The collagen coating did not significantly influence the mean viability of cells on the whole specimen surface. Interestingly, the alkaline phosphatase activity per cell on the collagen/calcium salt-coated specimens was higher than that on the as-received specimen. It was revealed that cathodic deposition is an effective technique to immobilize collagen fibrils on a 316L steel surface. 相似文献
518.
Rius-Ruiz FX Kisiel A Michalska A Maksymiuk K Riu J Rius FX 《Analytical and bioanalytical chemistry》2011,399(10):3613-3622
A novel potentiometric solid-state reference electrode containing single-walled carbon nanotubes as the transducer layer between
a polyacrylate membrane and the conductor is reported here. Single-walled carbon nanotubes act as an efficient transducer
of the constant potentiometric signal originating from the reference membrane containing the Ag/AgCl/Cl− ions system, and they are needed to obtain a stable reference potentiometric signal. Furthermore, we have taken advantage
of the light insensitivity of single-walled carbon nanotubes to improve the analytical performance characteristics of previously
reported solid-state reference electrodes. Four different polyacrylate polymers have been selected in order to identify the
most efficient reservoir for the Ag/AgCl system. Finally, two different arrangements have been assessed: (1) a solid-state
reference electrode using photo-polymerised n-butyl acrylate polymer and (2) a thermo-polymerised methyl methacrylate:n-butyl acrylate (1:10) polymer. The sensitivity to various salts, pH and light, as well as time of response and stability,
has been tested: the best results were obtained using single-walled carbon nanotubes and photo-polymerised n-butyl acrylate polymer. Water transport plays an important role in the potentiometric performance of acrylate membranes,
so a new screening test method has been developed to qualitatively assess the difference in water percolation between the
polyacrylic membranes studied. The results presented here open the way for the true miniaturisation of potentiometric systems
using the excellent properties of single-walled carbon nanotubes. 相似文献
519.
Bak A Magdziarz T Kurczyk A Polanski J 《Combinatorial chemistry & high throughput screening》2011,14(7):560-569
A detailed knowledge of hydrogen bond geometry and its directional preferences is vital for in silico investigations of the ligand-receptor short-range non-covalent interactions. The spatial arrangement of the carbonyl and hydroxyl groups seems to determine the capability of β-ketoenol derivatives to recognize the surrounding environment by forming inter- and intra-molecular hydrogen bonds (IHB). In the current study we examined the application of the MoStBioDat platform for a massive database screening of the IHB motifs in β-ketoenol subunits (O=C-C=C-OH). Then, the virtual 3D structural data derived from ZINC and PubChem repository were compared to the experimentally determined CSD data. Differences specific for each database were discovered, which indicated inaccuracies in the simulated data. 相似文献
520.