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91.
Alina Jasek Miroslaw Zimnoch Zbigniew Gorczyca Ewa Smula Kazimierz Rozanski 《Isotopes in environmental and health studies》2014,50(2):143-155
As urban atmosphere is depleted of 13CO2, its imprint should be detectable in the local vegetation and therefore in its CO2 respiratory emissions. This work was aimed at characterising strength and isotope signature of CO2 fluxes from soil in urban areas with varying distances from anthropogenic CO2 emissions. The soil CO2 flux and its δ13C isotope signature were measured using a chamber method on a monthly basis from July 2009 to May 2012 within the metropolitan area of Krakow, Southern Poland, at two locations representing different levels of anthropogenic influence: a lawn adjacent to a busy street (A) and an urban meadow (B). The small-scale spatial variability of the soil CO2 flux was also investigated at site B. Site B revealed significantly higher summer CO2 fluxes (by approximately 46 %) than site A, but no significant differences were found between their δ13CO2 signatures. 相似文献
92.
93.
Miroslaw Batentschuk Andres Osvet Gabi Schierning Andreas Klier Jürgen Schneider Albrecht Winnacker 《Radiation measurements》2004,38(4-6):539-543
Y3Al5O12:Ce3+ (YAG:Ce) and Tb3Al5O12:Ce3+ (TAG:Ce) both show the typical Ce3+ ion luminescence of the allowed Ce3+ d–f transition. Eu3+ codoping, however, reveals different results for both matrices: in YAG:Ce,Eu, only the luminescence of the Ce3+ ion occurs by excitation within the Ce3+ absorption bands. Here, the Eu3+ luminescence cannot be sensitized by the Ce3+ ion. But in TAG:Ce,Eu, both Ce3+ and Eu3+ luminescence are measured at several excitation wavelengths: an excitation within the Tb-sublattice results in both Ce3+ and Eu3+ luminescence, which is not surprising as an energy transfer from Tb3+ to Ce3+ and Eu3+ is well known in literature. In addition, an excitation in the lowest 5d level of Ce3+ delivers Eu3+ luminescence at room temperature. This means that the Ce3+ ion can be used as a sensitizer in the TAG lattice that transfers its energy via the Tb sublattice to the activator Eu3+. 相似文献
94.
Dr. Katherine Koh Dr. Udishnu Sanyal Dr. Mal-Soon Lee Dr. Guanhua Cheng Dr. Miao Song Dr. Vassiliki-Alexandra Glezakou Dr. Yue Liu Dr. Dongsheng Li Dr. Roger Rousseau Dr. Oliver Y. Gutiérrez Dr. Abhijeet Karkamkar Dr. Miroslaw Derewinski Prof. Johannes A. Lercher 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(4):1517-1521
Acid functionalization of a carbon support allows to enhance the electrocatalytic activity of Pd to hydrogenate benzaldehyde to benzyl alcohol proportional to the concentration of Brønsted-acid sites. In contrast, the hydrogenation rate is not affected when H2 is used as a reduction equivalent. The different responses to the catalyst properties are shown to be caused by differences in the hydrogenation mechanism between the electrochemical and the H2-induced hydrogenation pathways. The enhancement of electrocatalytic reduction is realized by the participation of support-generated hydronium ions in the proximity of the metal particles. 相似文献
95.
Ohne Zusammenfassung 相似文献
96.
Miroslaw Pluta Marie‐Amlie Paul Michaël Alexandre Philippe Dubois 《Journal of Polymer Science.Polymer Physics》2006,44(2):312-325
Plasticized polylactide (PLA) – layered silicate nanocomposites were obtained by melt blending PLA with polyethylene glycol as plasticizer (20 wt %) and with different montmorillonite fillers: Cloisite® 20A, Cloisite® 25A, and Cloisite® 30B (from 1 to 10 wt %). Comparative samples of melt‐blended polylactide (without filler) and plasticized PLA with 20 wt % PEG were considered as well. Samples have been aged for 1 and 4 years and their chemical and physical characteristics were compared with not aged reference ones. It was found that molecular weight of the PLA decreased upon melt‐processing and aging, particularly when the Cloisite content increased, without a clear relation to the nature of the organo‐modifier. On the contrary, the PEG plasticizer was practically undegraded upon melt processing and aging. Structural studies revealed that plasticized PLA and plasticized PLA‐based nanocomposites are unstable in time of aging and undergo deplasticization. They showed, after aging, the presence of a thin PEG crystalline layer at the surface of the samples and improved the order in the PLA matrix to a higher extent in plasticized polylactide than in plasticized nanocomposite (due to clay stabilization effect). The amount of PEG diffusing toward sample surface was correlated with aging time, molecular weight of PLA matrix, and Cloisite® type, in clear relation to the extent of intercalation with PLA and PEG. Some modifications of the viscoelastic properties of PLA matrix, induced by the presence of both the nanoparticlate filler and the plasticizer, as well as a deterioration of the mechanical properties upon aging were observed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 312–325, 2006 相似文献
97.
Miroslaw A. Karpierz 《Optics Communications》1992,90(4-6):241-244
An analytical solution is given for the nonlinear directional coupler with asymmetrically placed nonlinearity. It is shown that the distribution of nonlinearity influences the critical power value and changes the transmission characteristics. 相似文献
98.
Kramer-Marek G Serpa C Szurko A Widel M Sochanik A Snietura M Kus P Nunes RM Arnaut LG Ratuszna A 《Journal of photochemistry and photobiology. B, Biology》2006,84(1):1-14
Photodynamic therapy (PDT) and photodynamic diagnostics (PDD) of cancer are based on the use of non-toxic dyes (photosensitisers) in combination with harmless visible light. This paper reports physicochemical properties, cell uptake, localisation as well as photodynamic efficiency of two novel lipophilic porphyrin derivatives, suitable for use as PDT sensitisers. Both compounds are characterised by high quantum yield of singlet oxygen generation which was measured by time-resolved phosphorescence. Photodynamic in vitro studies were conducted on three cancer cell lines. Results of cell survival tests showed negligible dark cytotoxicity but high phototoxicity. The results also indicate that cell death is dependent on energy dose and time following light exposure. Using confocal laser scanning microscopy both compounds were found to localise in the cytoplasm around the nucleus of the tumour cells. The mode of cell death was evaluated based on the morphological changes after differential staining. In summary, good photostability, high quantum yield of singlet oxygen and biological effectiveness indicate that the examined lipophilic porphyrin derivatives offer quite interesting prospects of photodynamic therapy application. 相似文献
99.
Aleksandr V. Knyazev Miroslaw Mczka Nataliya N. Smirnova Lucyna Macalik Nataliya Yu. Kuznetsova Irene A. Letyanina 《Journal of solid state chemistry》2009,182(11):3003-3012
In the present work lithium (sodium) vanadium tungsten oxides with brannerite structure is refined by the Rietveld method (space group C2/m, Z=2). IR and Raman spectroscopy was used to assign vibrational bands and determine structural particularities. The diffuse reflectance spectra allow to calculate bandgap for MIVWO6(MI – Li, Na). The temperature dependences of heat capacity have been measured first in the range from 7 to 350 K for these compounds and then between 330 and 640 K, respectively, by precision adiabatic vacuum and dynamic calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity Cpo(T), enthalpy Ho(T)−Ho(0), entropy So(T)−So(0) and Gibbs function Go(T)−Ho(0), for the range from T→0 to 640 K. The differential scanning calorimetry was applied to measure decomposition temperature of compounds under study. 相似文献
100.
Angad Kumar Singh Sanyucta Kumari K. Ravi Kumar B. Sridhar Miroslaw Wrzecion Jerzy Mroziski T.R. Rao 《Polyhedron》2009,28(13):2599-2604