Summary A semi-quantitative technique by means of ESCA was applied to the surface state analysis of copper-nickel alloys. With area integrated intensity of peaks at the L3M4, 5M4, 5 region of copper and 2 p 3/2 region of nickel, cuprous state and nickel oxide state on alloys could be semi-quantitatively determined. As to oxygen states on alloy surfaces, interstitial (Cu2O and NiO states), non-stoichiometric (represents -OH) and molecular states (adsorbed) were estimated. Further, the surface composition of alloys after heating under high vacuum was discussed.
Einsatz von ESCA für die einfache halbquantitative Zustandsanalyse von Oberflächen von Kupfer-Nickel-Legierungen
Zusammenfassung Das ESCA-Verfahren wurde für die Untersuchung des Oberflächenzustandes von KupferNickel-Legierungen eingesetzt. Mit Hilfe der flächenintegrierten Peakintensitäten (L3 M4, 5 M4, 5 für Kupfer, 2 p 3/2 für Nickel) konnten Kupfer(II) und Nickeloxid auf den Legierungen halbquantitativ bestimmt werden. Sauerstoff wurde im interstitiellen (Cu2O, NiO) nichtstöchiometrischen (-OH) und molekularen (adsorbierten) Zustand gefunden. Weiterhin wurde die Oberflächenzusammensetzung der Legierungen nach Erhitzen im Hochvakuum diskutiert.
Ariakemicins A (1) and B (2), unusual linear hybrid polyketide-nonribosomal peptide antibiotics, were discovered from the fermentation extract of the marine gliding bacterium Rapidithrix sp. These metabolites were positional isomers with regard to a double bond and chromatographically inseparable, rendering the structure study on a mixture basis. The ariakemicins were composed of threonine, two omega-amino-(omega-3)-methyl carboxylic acids with diene or triene units, and delta-isovanilloylbutyric acid. The antibiotics selectively inhibited the growth of Gram-positive bacteria. 相似文献
A one-pot quick and efficient multicomponent reaction has been developed for the synthesis of a new series of functionalized 8-hydroxy-4-phenyl-1,2-dihydroquinoline derivatives using 30 mol% ammonium acetate in ethanol as solvent. This economical protocol run smoothly to give variety of quinoline derivatives in 55% to 98% yield from inexpensive reagents and catalyst in mild reaction conditions. Various spectroscopic techniques like FTIR, 1H NMR and 13C NMR, MALDI-TOF-MS, and EI-MS were used to study and confirm their structure. 相似文献
In single-molecule protein experiments, the observable variables are restricted within a small fraction of the entire degrees of freedom. Therefore, to investigate the physical nature of proteins in detail, we always need to estimate the hidden internal structure referring only to the accessible degrees of freedom. We formulate this problem on the basis of Bayesian inference, which can be applied to various complex systems. In the ideal case, we find that in general the framework actually works. Although careful numerical studies confirm that our method outperforms the conventional method by up to two orders of magnitude, we find a striking phenomenon: a loss-of-precision transition occurs abruptly when the design of the observation system is inappropriate. The basic features of the proposed method are illustrated using a simple but nontrivial model. 相似文献
A trace amount (0.5 mol%) of CuO-doped 40Li2O–32Nb2O5–28SiO2 glass (mol%) exhibits the formation of copper metal layers at the glass surface by annealing at temperatures (530 °C) below the glass transition temperature (544 °C) in the reduced atmosphere of 7% H2–93%Ar. The coordination state of copper ions is examined from optical absorption and Fourier transform infrared (FT-IR) spectrum measurements, indicating the formation of Si–OH and Si–H bonds due to the diffusion of hydrogen into the inside of the glass and the reduction of Cu+ and Cu2+ ions. The mechanism of the formation of copper metals at the surface is proposed, in which the key points are the reduction of Cu2+ to Cu+ ions due to the hydrogen and the migration of Cu+ ions in the interior of the glass to the surface. The first finding on copper metal layers at the glass surface might have a potential for practical applications such as electrodes in glass. 相似文献
We have designed and demonstrated a prototype on-beam spin-exchange optical pumping (SEOP) 3He neutron spin filter (NSF). It is designed as the incident neutron polarizer for spallation neutron sources, where the installation space is limited due to thick radiation shielding. The size of the NSF is roughly 50 cm×50 cm×25 cm including the diode-laser optics with a frequency narrowing external cavity, and a cylindrical 3He cell as large as a diameter of 5 cm and a length of 10 cm can fit. A neutron beam test was performed at the NOP beamline of JRR-3 to see the performance of the NSF. 相似文献
Addition reaction between C60 and ethylenediamine occurred at room temperature in an ambient condition. C60-ethylenediamine adduct particles were prepared by mixing toluene solutions of C60 and ethyelenediamine. Average diameter of the C60-ethylenediamine adduct particles was changed non-linearly according to the reaction time, which were observed using transmission electron microscopy. Early stage of the reaction, the diameter of the adduct particles was changed from about 250 to about 430 nm. Then, the size of the adduct particles was converged to about 300 nm. During this addition reaction, the crystalline sizes of adduct particles were constant about 2–3 nm, regardless of the sizes of the adduct particles, which were determined by X-ray diffraction measurement.
Initial oxidation of iron and manganese mono-silicides (FeSi and MnSi) surfaces was studied by X-ray photoelectron spectroscopy (XPS). Clean surfaces of these silicides were prepared by fracturing in an ultra high vacuum, and then the fractured surfaces were oxidized by exposing to high-purity oxygen at pressures up to 1.3 Pa. For the clean FeSi surface, positive chemical shifts of the Fe 2p3/2 and Si 2p peaks from elemental Fe and Si were 0.5 eV and 0.1 eV, respectively. For the clean MnSi surface, a negative chemical shift of the Si 2p peak from elemental Si was 0.1 eV. Iron on the FeSi surface was oxidized at an oxygen pressure of 1.3 Pa, whereas the silicon was oxidized under the pressure of 1.3 × 10−6 Pa, indicating that oxidation of silicon occurred prior to that of iron. Manganese and silicon on the MnSi were simultaneously oxidized in the range from 1.3 × 10−6 Pa to 1.3 × 10−3 Pa; however, over the pressure of 1.3 Pa, the oxidation of manganese occurs prior to that of silicon. These oxidation behaviors at low oxygen pressures were similar to those of the FeSi and MnSi fractured in air. 相似文献