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Ohne Zusammenfassung 相似文献
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Y.?Manzhur P. M.?Imielski K.?Potzger W. D.?Brewer M.?Dietrich M. J.?PrandoliniEmail author H. H.?Bertschat 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,46(4):535-540
The induced magnetism of isolated (Cd) adatoms,
soft-landed onto ultrathin Ni layers grown pseudo-morphologically
on Pd(001) (aPd = 3.8907 Å), was studied using the
perturbed angular correlation (PAC) technique. The magnitude of
the induced magnetic response (magnetic hyperfine field of
|5.2| T) was found to be ca. 30% smaller than on bulk Ni
(aNi = 3.524 Å) surfaces. This result is compared to ab initio calculations. Additionally, the magnetic anisotropy of
the induced response was found to be modified as compared to bulk
Ni surfaces and the induced hyperfine field was observed to emerge
from the plane at an angle of 50(5)○ to the surface
normal. This canted magnetic anisotropy is attributed to the large
lattice expansion of the ultrathin Ni film on Pd(001). 相似文献
118.
We study the equilibrium properties of a monomer-monomer A+B--> reaction on a two-dimensional substrate containing randomly placed catalytic bonds. Interacting A and B species undergo continuous exchanges with particle reservoirs and react as soon as a pair of unlike particles appears on sites connected by a catalytic bond. For annealed disorder in the placement of catalytic bonds the model is mapped onto a general spin S=1 model and solved exactly for the pressure in a particular case. At equal activities of the two species a second order phase transition is revealed. 相似文献
119.
The spirolides are a family of marine biotoxins derived from the dinoflagellate Alexandrium ostenfeldii, recently isolated from contaminated shellfish and characterized. A crude phytoplankton extract has been extensively studied for mass spectrometric determination and characterization of several known spirolides and previously unreported compounds. The complex sample was initially analyzed by full-scan mass spectrometry in an ion-trap instrument, enabling identification of several components. Subsequent analysis by selected-ion monitoring in a triple-quadrupole instrument resulted in the confirmation of the identities of the compounds detected in the ion trap. Purification of the crude extract was performed using an automated mass-based fractionation system, yielding several fractions with different relative contributions of the spirolide components. Collision-induced dissociation (CID) in the triple-quadrupole instrument produced significant fragment ions for all identified species. Selective enrichment of some minor compounds in certain fractions enabled excellent CID spectra to be generated; this had previously been impossible, because of interferences from the major toxins present. Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry was then performed for accurate determination of the masses of MH+ ions of all the species present in the sample. Additionally, infrared multiphoton dissociation in the FTICR instrument generated elemental formulae for product ions, including those formed in the previous collisional activation experiments. Collection of these results and the fragmentation scheme proposed for the main component of the extract, 13-desmethyl spirolide C, from part I of this study, enabled elucidation of the structures of some uncharacterized spirolides and some biogenetically related compounds present at previously unreported masses. 相似文献
120.
2-chloro-1,3,2-diazastibolenes react with Lewis acids either via Sb-Cl cleavage to yield stable Sb-analogues of an N-heterocyclic carbene, or via an unprecedented oxidative fragmentation to give a diazadiene-SbCl3 complex. 相似文献