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41.
42.
Stanley Gudder 《Foundations of Physics》1996,26(6):813-822
A D-algebra is a generalization of a D-poset in which a partial order is not assumed. However, if a D-algebra is equipped with a natural partial order, then it becomes a D-poset. It is shown that D-algebras and effect algebras are equivalent algebraic structures. This places the partial operation for a D-algebra on an equal footing with the partial operation for an effect algebra. An axiomatic structure called an effect stale-space is introduced. Such spaces provide an operational interpretation for the partial operations and . Finally, a relationship between effect-state spaces and torsion free interval effect algebras is demonstrated. 相似文献
43.
A beam of relativistic antihydrogen atoms — the bound state (
e+) — can be created by circulating the beam of an antiproton storage ring through an internal gas target. An antiproton which
passes through the Coulomb field of a nucleus will create e+e− pairs, and antihydrogen will form when a positron is created in a bound instead of continuum state about the antiproton.
The cross section for this process is roughly 3Z
2 pb for antiproton momenta about 6 GeV/c. A sample of 600 antihydrogen atoms in a low-emittance, neutral beam will be made in 1995 as an accidental byproduct of Fermilab
experiment E760. We describe a simple experiment, Fermilab Proposal P862, which can detect this beam, and outline how a sample
of a few-104 atoms can be used to measure the antihydrogen Lamb shift to 1 %.
Work supported in part by Department of Energy contract DE-AC03-76SF00515 (SLAC).
Work supported by Fondo Nacional de Investigación Científica y Tecnológica, Chile. 相似文献
44.
45.
We discuss the effects of the time correlations in the choice of growth sites for percolation clusters in two dimensions. To this end, we study two well-defined models: (i) FIFO (First-In, First-Out), in which the next-cluster growth site is theoldest, and (ii) FILO (First-In, Last-Out), where the next cluster growth site to be chosen is thenewest. We find that FIFO and FILO have dramatically differentkinetic exponents, even though thestatic exponents are the same (viz., percolation exponents). We find that the percolation thresholdp
c
is analogous to the point of a linear polymer, and we develop the corresponding tricritical point scaling relations.Dedicated to B. Mühlschlegel on the occasion of his 60th birthday 相似文献
46.
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48.
Summary A simple method is described for the introduction of samples to a gas Chromatograph by means of a septumless port. The reproducibility and accuracy of the method have been shown by the analysis of ng quantities of estrone, estradiol, and estriol as the heptafluorobutyrates with an electron capture detector.
Zusammenfassung Die Einbringung von Proben in einen Gaschromatographen durch einen membranlosen Einspritzblock wurde beschrieben. Die Reproduzierbarkeit und Genauigkeit der so erhaltenen Ergebnisse wurde durch die Bestimmung von Nanogrammengen Östron, Östradiol und Östriol als Heptafluorobutyrate mit einem Elektroneneinfangdetektor erwiesen.相似文献
49.
De Angelis AA Nevzorov AA Park SH Howell SC Mrse AA Opella SJ 《Journal of the American Chemical Society》2004,126(47):15340-15341
High-resolution solid-state NMR spectra can be obtained from uniformly (15)N-labeled membrane proteins in magnetically aligned bicelles. Fast uniaxial diffusion about the axis of the bilayer normal results in single-line spectra that contain the orientational information necessary for protein structure determination. 相似文献
50.
Salvador Puig-Torres Gary E. Martin Steven B. Larson Stanley H. Simonsen 《Journal of heterocyclic chemistry》1984,21(4):995-1000
Synthesis of the 1,3-diazaphenoxathiin ring system and the confirmation of its structure by 13C-nmr spectroscopy and X-ray crystallography are reported. Implications of the 13C-nmr chemical shift of the C-10a resonance and its relationship to the molecular dihedral angle are presented. The molecule crystallizes in the Pbca space group and was found to have a dihedral angle of 165.5(9)°, the structure refining to a final R-factor of T = 0.0427. 相似文献