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971.
972.
973.
H. Hübel G. Baldsiefen R.M. Clark S.J. Asztalos J.A. Becker L. Bernstein M.A. Deleplanque R.M. Diamond P. Fallon I.M. Hibbert R. Krücken I.Y. Lee A.O. Macchiavelli R.W. MacLeod G. Schmid F.S. Stephens K. Vetter R. Wadsworth 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):237-238
The properties of the M1 bands in the Pb region are reviewed. They can be explained by ‘magnetic rotation’ which is a new concept in nuclear excitations. Spin and excitation energy along the bands are increased by the shears effect, a step-by-step alignment of large proton-particle and large neutron-hole spins into the direction of the total angular momentum. First evidence is presented for band termination connected with the closing of the shears. 相似文献
974.
975.
The enantioseparation of basic compounds represent a challenging task in modern SFC. Therefore this work is focused on development and optimization of fast SFC methods suitable for enantioseparation of 27 biologically active basic compounds of various structures. The influences of the co-solvent type as well as different mobile phase additives on retention, enantioselectivity and enantioresolution were investigated. Obtained results confirmed that the mobile phase additives, especially bases (or the mixture of base and acid), improve peak shape and enhance enantioresolution. The best results were achieved with isopropylamine or the mixture of isopropylamine and trifluoroacetic acid as additives. In addition, the effect of temperature and back pressure were evaluated to optimize the enantioseparation process. The immobilized amylose-based chiral stationary phase, i.e. tris(3,5-dimethylphenylcarbamate) derivative of amylose proved to be useful tool for the enantioseparation of a broad spectrum of chiral bases. The chromatographic conditions that yielded baseline enantioseparations of all tested compounds were discovered. The presented work can serve as a guide for simplifying the method development for enantioseparation of basic racemates in SFC. 相似文献
976.
H. Greschonig M. G. Schmid G. Gübitz 《Fresenius' Journal of Analytical Chemistry》1998,362(2):218-223
Capillary zone electrophoresis was used to separate arsenite, arsenate, dimethylarsinic and diphenylarsinic acid, methanearsonic
acid, phenyl- and p-aminophenyl arsonic acid, phenylarsineoxide and phenarsazinic acid. Anionic and uncharged species were
separated in a fused silica capillary with on-column UV detection at 200 nm. A 15 mM phosphate solution adjusted to pH 6.5
containing 10 mM sodium dodecylsulfonate served as background electrolyte. The influence of pH and applied voltage on separation
efficiency, as well as the feasibility of identification of arsenic compounds in spiked urine, were investigated.
Received: 18 March 1998 / Revised: 25 May 1998 / Accepted: 30 May 1998 相似文献
978.
Roland Bliem Jessi van der Hoeven Adam Zavodny Oscar Gamba Jiri Pavelec Prof. Petra E. de Jongh Prof. Michael Schmid Prof. Ulrike Diebold Prof. Gareth S. Parkinson 《Angewandte Chemie (International ed. in English)》2015,54(47):13999-14002
Metal–support interactions are frequently invoked to explain the enhanced catalytic activity of metal nanoparticles dispersed over reducible metal oxide supports, yet the atomic‐scale mechanisms are rarely known. In this report, scanning tunneling microscopy was used to study a Pt1‐6/Fe3O4 model catalyst exposed to CO, H2, O2, and mixtures thereof at 550 K. CO extracts lattice oxygen atoms at the cluster perimeter to form CO2, creating large holes in the metal oxide surface. H2 and O2 dissociate on the metal clusters and spill over onto the support. The former creates surface hydroxy groups, which react with the support, ultimately leading to the desorption of water, while oxygen atoms react with Fe from the bulk to create new Fe3O4(001) islands. The presence of the Pt is crucial because it catalyzes reactions that already occur on the bare iron oxide surface, but only at higher temperatures. 相似文献
979.
Eigenvectors of vibrating polyethylene chains with (200) and (110) folds have been calculated by solving the phonon-scattering problem exactly with the method of Green's function. The results are applied to analyze the resonance modes of the (200) fold (ggtgg: 1353, 1356, 1374 cm–1) and the (110) fold (approximately ggggtg: 820, 1288, 1342, 1348, 1372, 1374 cm–1) in terms of the characteristic vibrations of smaller subunits of the (200) fold (gg, gtg) and the (110) fold (ggggtg, gggg, gtg) which can be identified spectroscopcally.Dedicated to Prof. Dr. W. Pechhold on the occasion of his 60th birthday 相似文献
980.
H.-S. Kitzerow H. Schmid A. Ranft G. Heppke R. A. M. Hikmet J. Lub 《Liquid crystals》2013,40(3):911-916
Abstract We report the first observation of cholesteric blue phases in chiral anisotropic polymer networks. In two-component mixtures of a chiral and a non-chiral diacrylate, we observed typical textures of BPI, BPII and BPIII phases. By photopolymerization of these materials at constant temperature we obtained blue phase networks. After polymerization, the blue phases were stored, which enabled us to further study them without any temperature control. 相似文献