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1.
2.
Ernst Lücker Anton Rosopulo Wilhelm Kreuzer 《Fresenius' Journal of Analytical Chemistry》1991,340(4):234-241
Summary The function of solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) in the laboratory-internal preparation, production and standardization of bovine liver reference material is described. Analytical quality assurance was achieved by using a wet digestion decomposition procedure and GFAAS (WD-GFAAS) as well as three different methods of SS-GFAAS. It will be shown, that SS-GFAAS is an adequate and efficacious method of analytical quality control in the production of reference materials. Details are given about the preliminary steps of sample selection and preparation, applying SS-GFAAS both as a screening method and for the detection of contamination during the production of the reference materials. The element contents of the four bovine liver materials measured after decomposition with nitric acid in the open system by GFAAS and also by Flame-AAS, using the slotted tube atom trap, are compared statistically with the results obtained by SS-GFAAS. In solid sampling analyses three different systems were applied: a solid sampling ZAA-spectrometer with platform-boat, a D2AA-spectrometer with solid sampling graphite tube and platform-drawer and an autoprobe-D2AA-spectrometer with solid sampling autoprobe and graphite tube. 相似文献
3.
Sommermann T Kim BG Peters K Peters EM Linker T 《Chemical communications (Cambridge, England)》2004,(22):2624-2625
Only three steps are required for the convenient synthesis of 2-C-branched glyco-amino acids from glycals with good yields and stereoselectivities. 相似文献
4.
Let (E, (ie63-01),) be a halfordered plane and call
convex if M contains for any two points a,bM all pointsx between a and b. It is shown that segments [a,b] are convex if and only if (E, (ie63-02)) is the affine plane of order 3, (E, (ie63-03),) is an ordered plane or is near-trivial.
Herrn Professor Johannes Böhm zum 70. Geburtstag gewidmet 相似文献
Herrn Professor Johannes Böhm zum 70. Geburtstag gewidmet 相似文献
5.
Alexander Kreuzer 《Geometriae Dedicata》1996,61(3):279-283
Let (P,
) and (P,
) be linear spaces satisfying the exchange axiom with dim P=dim P . Then a bijection :PP which maps collinear points onto collinear points is an isomorphism. Also a surjection :PP which maps any three non-collinear points to non-collinear points is an isomorphism. This assertion is not true if dim P is not finite. 相似文献
6.
Alexander Kreuzer 《Journal of Geometry》1996,56(1-2):87-98
We give a complete and short proof of KAHN's Theorem that every locally projective space (M,M) with dim M3 satisfying the Bundle Theorem is embeddable in a projective space. The central tool of KAHN's proof is the fact that (M,M) is locally projective, while we use mainly the Bundle Theorem.Dedicated to Professor Dr. H. Mäurer on the occasion of his sixtieth birthday 相似文献
7.
Alexander Kreuzer 《Journal of Geometry》1993,47(1-2):86-93
Using the function (x)=cosh x, K-loops on × are constructed. Since every K-loop is a Bruck loop, we have also examples for Bruck loops. Furthermore we investigate the group of the automorphisms a,b of the K-loop which satisfy the equation a(bc)=(ab)a,b(c).Dedicated to Professor Dr. Oswald Giering on the occasion of his 60 th birthday 相似文献
8.
Gerhard Talsky Lothar Mayring Hans Kreuzer 《Angewandte Chemie (International ed. in English)》1978,17(11):785-799
Derivative spectrophotometry has gained increasing importance in the past two years and is currently experiencing vigorous development. Following and introduction the present article provides a review of this extremely effective method. In particular, the advantages of higher-order derivative spectrophotometry (HODS method, n > 2) are discussed on the basis of practical examples from a wide range of analytical fields. The results are achieved with the aid of a newly developed analog computer unit, whereby for the first time readily reproducible, low-noise, on-line spectra can be obtained up to the 7th order and even, in favorable cases, up to the 9th order. In practice it has proved valuable to work with spectra of the 3rd to 5th order; but even higher derivations could be profitable for the separation of strongly superposed signals or for “fingerprinting”. 相似文献
9.
Wieslaw Wojnowski Barbara Becker Karl Peters Eva-Maria Peters Hans Georg von Schnering 《无机化学与普通化学杂志》1987,553(10):287-292
Structure of Pentaphenyldisilane For the first time Pentaphenyldisilane was prepared by Gilman and Goodman. It is produced by the reaction of Ph3SiLi with Ph2ClSiH. The crystal structure presents an ideally staggered conformation. The distance d(Si? Si) = 235.7 pm corresponds to a normal single bond length. This emphasizes the complete relief of the central Si? Si bond by the insertion of only one hydrogen atom. 相似文献
10.
Haplotype studies support slippage as the mechanism of germline mutations in short tandem repeats 总被引:1,自引:0,他引:1
Klintschar M Dauber EM Ricci U Cerri N Immel UD Kleiber M Mayr WR 《Electrophoresis》2004,25(20):3344-3348
Germline mutations of human short tandem repeat (STR) loci are expansions or contractions of repeat arrays which are not well understood in terms of the mechanism(s) underlying such mutations. Although polymerase slippage is generally accepted as a mechanism capable to explain most features of such mutations, it is still possible that unequal crossing over plays some role in those events, as most studies in humans could not exclude unequal crossing over (UCO). Crossing over can be studied by analyzing haplotypes using flanking markers. To check for UCO in mutations, we have analyzed 150 paternity cases for which more than the usual trio (mother, child, and father) were available for testing by analyzing 16 STR loci. In a total of 4900 parent-child allele transfers four mutations were observed at different loci (D8S1179, D18S51, D21S11, and SE33/ACTBP2). To identify the mutated allele and to check for UCO, we typed at least four informative loci flanking the mutated locus and used the pedigree data to establish haplotypes. By doing so we were able to exclude UCO in each case. Moreover, we were able to identify the mutations as one-repeat contractions/expansions. Our data thus support slippage as the mechanism of germline mutations in STRs. 相似文献