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121.
R. Klein R. Grieser L. Hoog G. Huber I. Klaft P. Merz T. Kühl S. Schröder M. Grieser D. Habs W. Petrich D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(4):455-461
We have performed for the first time precision spectroscopy on a coasting fast7Li+ ion beam in a storage ring. The ion beam moving with 6.4% speed of light was first electron cooled and then merged with two counterpropagating laser beams acting on two different hyperfine transitions sharing a common upper level (λ-system). One laser was frequency locked to thea 3 127J2 hfs frequency component established as a secondary frequency standard at 514 nm. The second laser was tuned over theλ-resonance, which was recorded relative to127J2 hfs components. This experiment is sensitive to the time dilation in fast moving frames and will lead to new limits for the verification of special relatively. The present status of the experiment and perspectives in accuracy are discussed. 相似文献
122.
123.
Fe2O3--V2O5 catalysts doped with Cs2SO4 (molar ratio: V:Fe:Cs=1:0.74:0.06) were found to be a rather inhomogeneous mixture of various crystalline and amorphous iron
vanadate phases. After calcination in air the catalyst was divided into three different parts which were analyzed separately
revealing the formation of FeVO4 in the top and bottom fraction of the crucible and Fe2V4O13 in the middle fraction. As compared to the well crystallized FeVO4 reference sample, the quadrupole splittings of FeVO4 in the Cs-doped catalysts were larger pointing to more distorted iron sites which were assumed to be responsible for high
catalytic selectivities. In contrast, the quadrupole splittings of FeVO4 in the less selective K- and Rb-doped Fe2O3--V2O5 catalysts were smaller. Additional components in the bottom fraction were also α-Fe2O3 and Fe1-xS. As indicated by the CEMS spectra the latter is located preferentially on the surface of the catalyst particles.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
124.
G. Dlubek R. Krause O. Brümmer J. Tittes 《Applied Physics A: Materials Science & Processing》1987,42(2):125-127
Positron-lifetime measurements have been used to study the annealing of vacancies in neutron-irradiated GaAs. The vacancies which are interpreted as defects in the Ga sublattice disappear in a single annealing stage (at 500°C in GaAs doped with Si or Zn, and at 600°C in Cr-doped GaAs). 相似文献
125.
126.
C. Scheidenberger K. Beckert P. Beller F. Bosch C. Brandau D. Boutin L. Chen B. Franzke H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov Yu. A. Litvinov M. Mazzocco G. Münzenberg F. Nolden W. R. Plaß M. Steck B. Sun H. Weick M. Winkler 《Hyperfine Interactions》2006,173(1-3):61-66
One important goal of the ILIMA project at FAIR is the study of masses and decay properties of relativistic isomeric beams
stored and cooled in the planned storage-ring complex. A new scheme is described, where a storage-cooler ring is used for
high-resolution mass separation. Experimental results on the separation of the isobaric pair 140Pr-140Ce are presented.
P. Beller, deceased. 相似文献
127.
128.
Dimitrios Tsikas Frank-Mathias Gutzki Jürgen C. Frölich 《Fresenius' Journal of Analytical Chemistry》1992,342(1-2):95-97
Summary A reversed-phase HPLC method for the determination of nitrite and nitrate in aqueous solutions, biological buffers and human urine is described. The method is based on the conversion of nitrite and nitrate into their 1-nitro-2,4,6-trimethoxybenzene (NTBM) derivatives by using 1,3,5-trimethoxybenzene and concentrated sulphuric acid. NTMB is extracted by benzene, the solvent evaporated, the residue reconstructed in methanol/water (3/4, v/v) and subsequently analyzed by reversed-phase HPLC and UV detection (360 nm). The specificity of the nitration reaction, good reproducibility (C.V. 6.2%) and high sensitivity (8.4 ng nitrite) show the applicability of this method to the quantitative analysis of nitrite and nitrate in several matrices including human urine. 相似文献
129.
130.
A quick sample preparation method was used for the determination of sulphur and trace metals in oil and oily products by the ICP with a minitorch. Stable aqueous emulsions of oils and oil products were made by using two kinds of emulsifiers (one with low sulphur content, the other sulfonated). Aqueous standard solutions can be used for the preparation of calibration solutions. The contents of S, Al, Cr, Cu, Fe, Mg, Ni and Pb in aqueous emulsions were determined and the results were in good agreement with the composition of oil standard solutions used for control analysis procedure. 相似文献