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31.
W.E. OGrady Lj. Atanasoska F.H. Pollak H.L. Park 《Journal of Electroanalytical Chemistry》1984,178(1):61-68
The surface structure of RuO2 (110) has been studied with LEED, AES and XPS. The “as-grown” surface shows no LEED patterns and both AES and XPS indicate that the surface is depleted in oxygen in high vacuum. After extensive annealing in an O2 atmosphere reproducible LEED patterns characteristic of the (110) surface were obtained. For the well-ordered surface the oxygen XPS results revealed oxygen associated with the bulk RuO2, the presence of RuO3 and oxygen bound to surface atoms. 相似文献
32.
Michael R. Whalon Gilbert L. Grady Paul McGoff Raymond P. Domingue C.Hackett Bushweller 《Tetrahedron letters》1982,23(50):5247-5250
1H NMR spectra at low temperature for five 1,3-disubstituted-2,2-dimethylpropanes reveal a strong preference for one molecular geometry (C2 symmetry) which is qualitatively consistent with empirical force field calculations. 相似文献
33.
Fragmentation of metal rings by electromagnetic loading 总被引:9,自引:0,他引:9
A method is described for performing fragmentation studies on rapidly expanding metal rings. A fast-discharge capacitor system
generates magnetic forces which accelerate the rings to maximum radial velocities of approximately 200 m/s corresponding to
circumferential-strain rates of approximately 104/s at fragmentation. Streak-camera techniques are used to record the time-resolved motion of the rings. Fracture-strain and
fragmentation experiments have been performed on samples of OFHC copper and 1100-0 aluminum. 相似文献
34.
35.
Annika M. Weber Huong Thi Huynh Nguyen Grady Hanrahan 《Analytical and bioanalytical chemistry》2014,406(5):1447-1454
This study demonstrates an untested link between model phenolic compounds and the formation/electrophoretic separation of stable urinary metabolites. Sterically encumbered carbonyl groups were examined, and mass determination was used to confirm the presence and stability of two oxidative metabolites of pentachlorophenol: tetrachloro-1,2-benzoquinone and tetrachloro-1,4-dihydroquinone. Subsequently, baseline resolved separation of pentachlorophenol and the two oxidative metabolites was demonstrated under the following conditions: 75 mM sodium tetraborate buffer (pH?=?8.5) with 5 % methanol and 50 mM SDS, +10.0 kV running voltage, injection time?=?5.0 s, effective capillary length?=?55 cm, and run temperature?=?20 °C. Results not only provide key metabolic inferences for pentachlorophenol, they also exhibit improvements in the ability to separate and detect changes in urinary metabolites in response to phenolic-related exposure. Figure
Metabolic pathway elucidation towards time- and dose-dependent electrophoretic screening of stable oxidative phenolic compounds. Establishing direct pathways and developing sensitive/selective analytical tools to measure and characterize xenobiotics provides a defined link between potential hazards and suspected health effects. 相似文献
36.
Résumé On généralise un résultat de Dobbs-Lancaster sur les espaces vectorielles au cadre des modules sur un anneau principal spécial
finiR. SoitV une module libre de type fini. On trouve une formule explicite et des valeurs dans la limite du nombre anticipé de générateurs
d’un sousmodule arbitraire deV. De plus, on calcule ces valeurs anticipés quand tout sousmodule a un poids naturel (par exemple, quant a sa cardinalité)
相似文献
37.
Gravitational synchrotron radiation is studied using the techniques of geometrical optics. It is found that the geometry of the Schwarzschild black hole creates a rotating searchlight effect, even for a source particle which radiates only during an infinitesimally brief interval of coordinate time. The period of rotation of the searchlight is shown to provide a measurement of the mass of the blackhole, since the period T is related to the mass M by T = 2π271/2 M for the Schwarzschild geometry and by T = 4πM for the extreme (a = M) Kerr geometry. 相似文献
38.
A Gurtu P K Malhotra I S Mittra P M Sood SC Gupta VK Gupta GL Kaul LK Mangotra Y Prakash NK Rao ML Sharma 《Pramana》1974,3(5):311-322
This is a continuation of our earlier investigation (Gurtuet al 1974Phys. Lett. 50 B 391) on multiparticle production in proton-nucleus collisions based on an exposure of emulsion stack to 200 GeV/c beam at the NAL. It is found that the ratioR em = 〈n s〉/〈n ch〉, where 〈n ch〉 is the charged particle multiplicity in pp-collisions, increases slowly from about 1 at 10 GeV/c to 1·6 at 68 GeV/c and attains a constant value of 1·71 ± 0·04 in the region 200 to 8000 GeV/c. Furthermore,R em = 1·71 implies an effectiveA-dependence ofR A =A 0.18,i.e., a very weak dependence. Predictions ofR em on various models are discussed and compared with the emulsion data. Data seem to favour models of hadron-nucleon collisions in which production of particles takes place through adouble step mechanism,e.g., diffractive excitation, hydrodynamical and energy flux cascade as opposed to models which envisage instantaneous production. 相似文献
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40.
The first detailed examination of flow injection-capillary electrophoresis (FI-CE) active parameters and their interactions via response surface methodology (RSM) is presented. Specifically, RSM in the form of a Box-Behnken design was implemented to effectively predict the significance of capillary length, voltage and injection volume on the optimization of an in-house built FI-CE analyzer. Initial studies were performed assessing peak height and peak shape of the model compound N,N-dimethylformamide. Optimum model conditions were then derived and used in the model separation of two small molecules, nicotinamide adenine dinucleotide, reduced form (NADH) and benzenesulfonamide. By implementing the RSM approach, detailed examination of active FI-CE parameters was possible, including the ability to reveal a significant interactive effect. This work is not only highly significant for advancing FI-CE developments, but instructive for investigators actively exploring other coupled analytical techniques and associated experimental parameters. 相似文献