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221.
Włodzimierz Godłowski Marek Szydłowski Piotr Flin Monika Biernacka 《General Relativity and Gravitation》2003,35(5):907-913
We discuss the equation of motion of the rotating homogenous and isotropic model of the Universe. We show that the model predicts the presence of a minimum in the relation between the mass of an astronomical object and its angular momentum. We show that this relation appears to be universal, and we predict the masses of structures with minimal angular momenta in agreement with observations. In such a manner we suggest the possibility at acquirement of angular momenta of celestial bodies during their formation from the global rotation of the Universe. 相似文献
222.
Monika Kuemmel Cédric Boissière Lionel Nicole Christel Laberty-Robert Clément Sanchez David Grosso 《Journal of Sol-Gel Science and Technology》2008,48(1-2):102-112
TiO2, Al2O3, and ZrO2 patterns composed of ordered nano motifs of various morphologies (i.e. perforations (craters), rings, canyons, wires, dots, or channels) with typical lateral dimensions of less than 40 nm and thickness below 15 nm are presented. Simple chemical solution deposition (CSD) of molecular inorganic precursors and commercial block copolymers was used to create patterns on several substrate surfaces (bare, hydrophobized or gold covered silicon wafers and ITO). Self-assembly during evaporation and subsequent stabilization at 500 °C leads to the various nanostructures. Compared to other techniques for surface nano patterning, the present method has the advantage of being cheap, reproducible and easy to scale up and does not require specialized equipment. The type, dimension, and organization of these motifs were assessed by AFM, FE-SEM, spectroscopic ellipsometry, and GI-SAXS and are shown to depend on the conditions of preparation. Usage as model surfaces for modelling of wetting properties and as nanoelectrode arrays were investigated. 相似文献
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225.
Wolfgang Specht und Monika Tillkes 《Fresenius' Journal of Analytical Chemistry》1985,322(5):443-455
Zusammenfassung Für die im Jahre 1980 veröffentlichte Methode zur Aufarbeitung von Lebensmitteln und Futtermitteln für die Multirückstandsanalyse von Pflanzenbehandlungsmitteln [1] wird eine wesentlich erweiterte Tabelle der Bedingungen bei Gel-Chromatographie und MiniKieselgel-Säulen-Chromatographie von Pflanzenschutzmittel-Wirkstoffen, deren Metaboliten und Abbauprodukten sowie von umweltrelevanten Stoffen mitgeteilt. Es werden zusätzliche Hinweise zu den einzelnen Arbeitsschritten der 3. Mitteilung gegeben. Insgesamt werden Elutionsdaten für die Gel-Chromatographie und für die Mini-Kieselgel-Säulen-Chromatographie von mehr als 400 Stoffen aufgeführt.
1. Mitt. (1979) Organochlorpflanzenbehandlungsmittel in Tabak und Tabakerzeugnissen. Beitr Tabakforsch Int 10:73–79
2. Mitt. (1980) Bestimmung der Fungicide Bitertanol, Fluotrimazol, Fuberidazol, Imazalil, Rabenzazole, Triadimefon und Triadimenol in Pflanzen und Boden. Pflanzenschutz-Nachrichten Bayer 33:61–85
3. Mitt. (1980) Methode zur Aufarbeitung von Lebensmitteln und Futtermitteln pflanzlicher und tierischer Herkunft für die Multirückstandsbestimmung lipoid- und wasserlöslicher Pflanzenbehandlungsmittel. Fresenius Z Anal Chem 301:300–307
4. Mitt. (1981) Gas-chromatographische Bestimmung von 11 herbiciden Phenoxyalkancarbonsäuren und ihren Estern in Pflanzenmaterial. Fresenius Z Anal Chem 307:257–264 相似文献
Gas-chromatographic determination of pesticide residues after clean-up by gel-permeation chromatography and mini-silicagel-column chromatographyPart 5. Clean-up of foods and feeds of vegetable and animal origin for multiresidue analysis of fat-soluble and water-soluble pesticides
Summary An extended list of gel-permeation chromatography (GPC) conditions and mini-silicagel column chromatography conditions for the analysis of pesticides using the multiresidue method, first published in 1980 [1], is presented. Data for the elution of more than 400 pesticides, their metabolites and pollutants are given.
1. Mitt. (1979) Organochlorpflanzenbehandlungsmittel in Tabak und Tabakerzeugnissen. Beitr Tabakforsch Int 10:73–79
2. Mitt. (1980) Bestimmung der Fungicide Bitertanol, Fluotrimazol, Fuberidazol, Imazalil, Rabenzazole, Triadimefon und Triadimenol in Pflanzen und Boden. Pflanzenschutz-Nachrichten Bayer 33:61–85
3. Mitt. (1980) Methode zur Aufarbeitung von Lebensmitteln und Futtermitteln pflanzlicher und tierischer Herkunft für die Multirückstandsbestimmung lipoid- und wasserlöslicher Pflanzenbehandlungsmittel. Fresenius Z Anal Chem 301:300–307
4. Mitt. (1981) Gas-chromatographische Bestimmung von 11 herbiciden Phenoxyalkancarbonsäuren und ihren Estern in Pflanzenmaterial. Fresenius Z Anal Chem 307:257–264 相似文献
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227.
The thermodynamics and kinetics of zinc-cytochrome c (ZnCyt c) interactions with Escherichia coli molecular chaperone GroEL (Chaperonin 60; Cpn60) are described. Zinc(II)-porphyrin represents a flexible fluorescent probe for thermodynamic complex formation between GroEL and ZnCyt c, as well as for stopped-flow fluorescence kinetic experiments. Data suggests that GroEL and GroEL/GroES-assisted refolding of unfolded ZnCyt c takes place by a mechanism that is quite close to the Anfinsen Cage hypothesis for molecular chaperone activity. However, even in the presence of ATP, GroEL/GroES-assisted refolding of ZnCyt c takes place at approximately half the rate of refolding of ZnCyt c alone. On the other hand, there is little evidence for refolding behaviour consistent with the Iterative Annealing hypothesis. This includes a complete lack of GroEL or GroEL/GroES-assisted enhancement of refolding rate constant k(2) associated with the unfolding of a putative misfolded state I (Zn) on the pathway to the native state. Reviewing our data in the light of data from other laboratories, we observe that all forward rate enhancements or reductions could be accounted for in terms of thermodynamic coupling (adjusting positions of refolding equilibria) due to binding interactions between GroEL and unfolded protein substrates, driven by thermodynamic considerations. Therefore, we propose that passive kinetic partitioning should be considered the core mechanism of the GroEL/GroES molecular chaperone machinery, wherein the core function is to bind unfolded protein substrates leading to a blockade of aggregation pathways and to increases in molecular flux through productive folding pathway(s). 相似文献
228.
Ab initio electronic structure methods are used to estimate the cross sections for electron transfer from donor anions having electron binding energies ranging from 0.001 to 0.6 eV to each of three sites in a model disulfide-linked molecular cation. The three sites are (1) the S-S sigma(*) orbital to which electron attachment is rendered exothermic by Coulomb stabilization from the nearby positive site, (2) the ground Rydberg orbital of the -NH(3)(+) site, and (3) excited Rydberg orbitals of the same -NH(3)(+) site. It is found that attachment to the ground Rydberg orbital has a somewhat higher cross section than attachment to either the sigma orbital or the excited Rydberg orbital. However, it is through attachment either to the sigma(*) orbital or to certain excited Rydberg orbitals that cleavage of the S-S bond is most likely to occur. Attachment to the sigma(*) orbital causes prompt cleavage because the sigma energy surface is repulsive (except at very long range). Attachment to the ground or excited Rydberg state causes the S-S bond to rupture only once a through-bond electron transfer from the Rydberg orbital to the S-S sigma(*) orbital takes place. For the ground Rydberg state, this transfer requires surmounting an approximately 0.4 eV barrier that renders the S-S bond cleavage rate slow. However, for the excited Rydberg state, the intramolecular electron transfer has a much smaller barrier and is prompt. 相似文献
229.
Shiva Kumar Monika Mudgel Anjana Dogra M. Husain V.P.S. Awana Hari Kishan 《Physica C: Superconductivity and its Applications》2010
Synthesis and structural details of MSr2RECu2Oz (M-1212) compounds with M = Ga, Nb, Fe, Al and Co) and RE = Eu, Y are reported. Reitveld refinement of X-ray diffraction (XRD) patterns shows that all compounds are crystallized in single phase. Nb-, Fe- and Al-1212 possess tetragonal P4/mmm space group structure while the Ga-1212 and Co-1212 are crystallized in orthorhombic Ima2 space group. The change of space group from P4/mmm to Ima2 indicating towards the doubling of unit cell. The buckling angle [Cu(2)–O(2)–Cu(2) angle] shows that most of the studied samples are heavily under doped and hence they could not exhibit superconductivity. Thermogravimetric (TGA) analysis shows the M-1212 compounds to be more stable than widely studied 90 K superconductor Cu-1212 (RE-123). 相似文献
230.
Monika Dockendorff Horacio Solar 《International Journal of Mathematical Education in Science & Technology》2018,49(1):66-84
This case study investigates the impact of the integration of information and communications technology (ICT) in mathematics visualization skills and initial teacher education programmes. It reports on the influence GeoGebra dynamic software use has on promoting mathematical learning at secondary school and on its impact on teachers’ conceptions about teaching and learning mathematics. This paper describes how GeoGebra-based dynamic applets – designed and used in an exploratory manner – promote mathematical processes such as conjectures. It also refers to the changes prospective teachers experience regarding the relevance visual dynamic representations acquire in teaching mathematics. This study observes a shift in school routines when incorporating technology into the mathematics classroom. Visualization appears as a basic competence associated to key mathematical processes. Implications of an early integration of ICT in mathematics initial teacher training and its impact on developing technological pedagogical content knowledge (TPCK) are drawn. 相似文献