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141.
142.
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
143.
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
144.
145.
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
146.
Let R be a local ring and let (x
1, …, x
r) be part of a system of parameters of a finitely generated R-module M, where r < dimR
M. We will show that if (y
1, …, y
r) is part of a reducing system of parameters of M with (y
1, …, y
r) M = (x
1, …, x
r) M then (x
1, …, x
r) is already reducing. Moreover, there is such a part of a reducing system of parameters of M iff for all primes P ε Supp M ∩ V
R(x
1, …, x
r) with dimR
R/P = dimR
M − r the localization M
P of M at P is an r-dimensional Cohen-Macaulay module over R
P.
Furthermore, we will show that M is a Cohen-Macaulay module iff y
d is a non zero divisor on M/(y
1, …, y
d−1) M, where (y
1, …, y
d) is a reducing system of parameters of M (d:= dimR
M). 相似文献
147.
148.
In this paper we address the problem of scheduling unit time jobs in a flowshop to minimize makespan under a discrete renewable resource constraint. We propose algorithms having complexityO(n) for special cases of two machine and three machine problems. For the three machineN P-hard problem we develop a branch and bound procedure and several upper and lower bounds. We test the efficiency of the procedure and report our computational experience.Suna Kondakci was a visiting assistant professor at the Industrial Engineering Department, Purdue University, when the paper was revised. 相似文献
149.
150.
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