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51.
Boguslaw Kusz Leon Murawski Ryszard Barczynski Ivan Davoli Olgierd Gzowski Sergio Stizza 《Journal of Materials Science》1990,25(4):2125-2128
The internal friction (Q
–1) spectrum of YBa2Cu3Ox superconducting ceramic exhibits several peaks. It has been confirmed that the high-temperature peak (around 240 K) depends on structural changes and varies during subsequent cycles of cooling and heating.Q
–1 conductivity, X-ray spectra and the shielding effect have been measured on several samples having different superconducting properties obtained by various thermal treatments. Splitting is a characteristic feature of the high-temperature internal friction peak of the sample which exhibits good superconducting properties. In the case of the specimen exhibiting the worst properties the peaks decrease and overlap. In both cases an increase can be observed of this peak with the number of thermal cycles. After ageing at 470 K, the high-temperature peak disappears. Subsequent thermal cycles slightly recover it. Hysteresis of the Young modulus is also observed. The results are interpreted as transition of the 04 oxygen atom between two energy minima in the O4-Cu-O4 chain. 相似文献
52.
Ryszard J. Kaleczuk 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,64(4):398-406
BET, scanning electron microscopy, X-ray diffraction, Mössbauer spectroscopy, X-ray fluorescence spectroscopy and McBain thermobalance were used to investigate the effect of cobalt on the reduction behavior and activity of used iron catalyst for ammonia synthesis. Activity tests were carried out under 10 MPa in the 350–450°C temperature rang. Studies were performed on the traditional multipromoted iron catalyst and on the series of catalysts prepared with addition of cobalt. Addition of cobalt promoted the iron catalyst for ammonia synthesis. The most active sample was that containing approx. 5.5% wt Co. Cobalt changed the reduction behavior of the catalyst. The rate of the surface change during reduction was higher for the case of the ‘cobalt catalyst’; however the rate of mass change was higher for a typical iron catalyst. The process of reduction was probably followed by the formation of an Fe3Co compound and by the surface faceting, with the exposure of an Fe(111) plane. 相似文献
53.
Uniqueness in Shape from Shading Revisited 总被引:1,自引:0,他引:1
Ryszard Kozera 《Journal of Mathematical Imaging and Vision》1997,7(2):123-138
We analyse the problem of representing solutions of first-orderpartial differential equations in terms of complete integrals and envelopes. In this context, we revisit the uniqueness results alreadyexisting in the shape-from-shading literature that concern eikonalequations corresponding to the images of a Lambertian hemi-sphere and aLambertian plane. We show that the approach adopted by Brooks in [2, 3] isincomplete and subsequently re-establish its uniqueness claims. 相似文献
54.
Erörterung der Zusammenhänge zwischen physikalisch-chemischen Eigenschaften und der Fehlordnung kristalliner Stoffe. Übersicht über die bisherigen Ergebnisse von Untersuchungen zur Fehlordnung von Wüstit und über die daraus abgeleiteten Modelle. Erläuterung eigener Röntgenbeugungsmessungen und thermogravimetrischer Untersuchungen. Beschreibung eines Modells für die Fehlordnung des Wüstits im Temperaturbereich von rd. 970 bis 1370 K. Ermittlung der Temperaturabhängigkeit der Gleichgewichtskonstante für die Bildung von ?Komplexdefekten?. 相似文献
55.
Zbigniew Jedliński Andrej Stolarzewicz Pawel Szewczyk Ryszard Tymczyński 《Polymer Bulletin》1980,2(8):555-563
Summary Polymerization of p-chlorophenyl glycidyl ether initiated by potassium glycolates (ethylene, propylene and 2-methyl propylene glycolatea) in DMSO containing some 18-crown-6 ether or glycol was investigated. For the reaction system containing the propylene glycolate asymmetrically substituted with a methyl group, relatively high polymerization rates were obtained as compared with those found for the other systems studied, the resultant polymers also having higher molecular weights and comparatively low polydispersities. Aliphatic double bonds were found to be absent in the polymers synthesized, which would suggest that in the anionic polymerization process studied the growing chain is not transferred to the monomer.Dedicated to Prof. C.I. Simionescu on the occasion of the 60th anniversary of his birthday 相似文献
56.
57.
Ryszard Amarowicz Zofia Żegarska Ryszard Rafałowski Ronald B. Pegg Magdalena Karamać Agnieszka Kosińska 《European Journal of Lipid Science and Technology》2009,111(11):1111-1117
Phenolic compounds were extracted from thyme (Thymus vulgaris L.), oregano (Origanum vulgare L.) and marjoram (Origanum majorana L.) with 95% ethanol. A number of antioxidant and radical‐scavenging capacity tests were performed on the prepared extracts using colorimetric assays and model system studies. Specifically, these included determining the content of total phenolics, antioxidant efficacy in a linoleic acid‐ferric thiocyanate model system, reducing power, scavenging effect on 2,2'‐diphenyl‐1‐picrylhydrazyl radical, and hydroxyl radical‐scavenging activity by electron paramagnetic resonance spectroscopy. Moreover, the efficacies of the prepared herb extracts were investigated in a real‐life food product: the stabilization of butter against oxidation. 相似文献
58.
Over the last decade, dendritic structures including hyperbranched polymers, dendrigrafts, dendrons, and dendrimers due to their distinct structural design such as highly branched structure and a large number of reactive end groups have received considerable attention. Among various kind of dendrimer, particularly amine-terminated dendritic materials like polyamidoamine (PAMAM), polypropylene imine (PPI), and polyethylene imine (PEI) have been introduced as the potential candidates in a wide range of areas, particularly in the field of textiles engineering. Hence, this review provides an introduction of amine-terminated dendritic polymers and new potential applications of them in textiles engineering such as improvement of dyeability, salt-free dyeability, antimicrobial activity, long-lasting fragrant fabric, anti-ultraviolet property, drug delivery through fabric, flame retardancy, and wastewater treatment. Regarding the complex synthesis of dendrimers which makes them expensive products, application of amine-terminated hyperbranched polymers provides affordable dendritic polymers to create novel features. 相似文献
59.
Piotr Domagalski Marek Dziubinski Ryszard Pawlak Mariusz Tomczyk 《Particulate Science and Technology》2018,36(5):529-533
A novel method for the determination of the average shear rate around a microparticle moving in the fluid is presented. Although the shear rate around a particle moving in the fluid is a parameter of paramount importance in sedimentation studies, its determination is time-consuming, thus model-based solutions are preferred. However, the current literature models require still rigorous validation. The presented technique relies on optical tracking of a laser-tweezers trapped particle suspended in the liquid medium. The obtained experimental results for spherical particles of 1 micron diameter show a good agreement with the classical rheology and literature correlation models. The new method is a valuable tool for determination of sedimentation parameters as it reduces the time of experiments and the sample volume by order(s) of magnitude when compared to classical methods. 相似文献