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101.
102.
Francęois D. Tropper Fredrik O. Andersson Suoding Cao René Roy 《Journal of carbohydrate chemistry》2013,32(6):741-750
Abstract Peracetylated glycosyl- and glycobiosyl bromides and chlorides 1-4 including acetochloroneuraminic acid 5 were stereoselectively transformed into their corresponding S-glycosyl xanthates 6-10 in high yield (91-98%) under phase transfer catalyzed conditions. The reactions occurred at room temperature using tetrabutylammonium hydrogen sulfate as the catalyst. The substitutions gave complete inversion of configuration and thus proceeded by an SN2 type mechanism. Changing the organic solvent from methylene chloride to ethyl acetate had no detrimental effect on the outcome of the reactions but avoided an undesirable side reaction between the xanthate anion and methylene chloride. 相似文献
103.
104.
Remote sample characterization based on fluorescence monitoring 总被引:3,自引:0,他引:3
The possibilities and limitations of remote sample characterization using induced fluorescence are discussed. General equations for remote sensing of fluorescence are presented and discussed. The implications of different elements of a system for remote fluorescence sensing on different parameters of the equations are treated. Background light influence and signal processing are considered. Pulsed lasers, flashlamps and cw lamps as excitation sources are compared when matched to the proper detection scheme employing boxcar integration or lock-in detection. Model experiments have been performed to demonstrate different measurement strategies. Examples from remote oil-slick characterization are chosen as illustrations. 相似文献
105.
106.
B. Andersson G. Gustafson L. Lönnblad U. Pettersson 《Zeitschrift fur Physik C Particles and Fields》1989,44(4):625-632
A superfield action for the relativistic massless superparticle as a spinning particle is presented in the new gauge. The symmetries in the relativistic superparticle theory, that is to say, the invariances under, the reparametrization and the local supersymmetry-transformation in the parameter space, are manifest in this formalism. It is clear how these two kinds of transformations descend from a unified origin to be called “super-reparametrization”, which is a restricted form of the general coordinate transformation in the superspace. The action is manifestly invariant under these transformation by its constructions The minimal coupling with electromagnetic field is also constructed in the superfield formalism, and a manifestly invariant superfield action for the interacting superparticle is presented in our gauge. The formalism is extended to the construction of an action for theN=2 superparticle. 相似文献
107.
108.
Martin Sahlberg Premysl Beran Thomas Kollin Nielsen Yngve Cerenius Krisztina Kads Marko P.J. Punkkinen Levente Vitos Olle Eriksson Torben R. Jensen Yvonne Andersson 《Journal of solid state chemistry》2009,182(11):3113-3117
A novel aluminium rich alloy for hydrogen storage has been discovered, ScAl0.8Mg0.2, which has very promising properties regarding hydrogen storage capacity, kinetics and stability towards air oxidation in comparison to hydrogen absorption in state-of-the-art intermetallic compounds. The absorption of hydrogen was found to be very fast, even without adding any catalyst, and reversible. The discovered alloy crystallizes in a CsCl-type structure, but decomposes to ScH2 and Al(Mg) during hydrogen absorption. Detailed analysis of the hydrogen absorption in ScAl0.8Mg0.2 has been performed using in situ synchrotron radiation powder X-ray diffraction, neutron powder diffraction and quantum mechanical calculations. The results from theory and experiments are in good agreement with each other. 相似文献
109.
Sarifuddin Santabrata Chakravarty Prashanta Kumar Mandal Helge I. Andersson 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,56(Z2):299-323
The present investigation deals with a mathematical model representing the mass transfer to blood streaming through the arteries
under stenotic condition. The mass transport refers to the movement of atherogenic molecules, that is, blood-borne components,
such as oxygen and low-density lipoproteins from flowing blood into the arterial walls or vice versa. The blood flowing through
the artery is treated to be Newtonian and the arterial wall is considered to be rigid having differently shaped stenoses in
its lumen arising from various types of abnormal growth or plaque formation. The nonlinear unsteady pulsatile flow phenomenon
unaffected by concentration-field of the macromolecules is governed by the Navier–Stokes equations together with the equation
of continuity while that of mass transfer is controlled by the convection-diffusion equation. The governing equations of motion
accompanied by appropriate choice of the boundary conditions are solved numerically by MAC(Marker and Cell) method and checked
numerical stability with desired degree of accuracy. The quantitative analysis carried out finally includes the respective
profiles of the flow-field and concentration along with their distributions over the entire arterial segment as well. The
key factors like the wall shear stress and Sherwood number are also examined for further qualitative insight into the flow
and mass transport phenomena through arterial stenosis. The present results show quite consistency with several existing results
in the literature which substantiate sufficiently to validate the applicability of the model under consideration. 相似文献
110.
K. Andersson G. Borchardt S. Scherrer S. Weber 《Fresenius' Journal of Analytical Chemistry》1989,333(4-5):383-385
Summary The use of neutral primary particles for secondary ion mass spectrometry (NPB-SIMS) makes it possible to analyse the isotope concentration profiles of all constituent elements in Mg2SiO4 simultaneously. The results indicate
Selbstdiffusion in Mg2SiO4 (Forsterit) bei hoher Temperatur: Modelluntersuchung für SIMS-Analysen an keramischen Oberflächen相似文献