Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co–Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism.     

Application of metalloporphyrins and methylviologen-pendent iron porphyrin to reduction of diphenylsulfoxide

In the two-electron reduction of diphenylsulfoxide to diphenylsulfide, which is considered a model reaction of sulfite reduction catalyzed by sulfite reductase, methylviologen-pendent iron(III) porphyrin exhibits much higher catalytic activity than usual iron(III) and manganese(III) tetraphenylporphyrins, while cobalt(II) tetraphenylporphyrin exhibits much less catalytic activity than the others. Discussion about the active species and the reason of the acceleration by methylviologen-pendent is presented.     

Quantitative analysis of triphenylboron in environmental water samples by liquid chromatography/mass spectrometry.

Liquid chromatography/mass spectrometry (LC/MS) has been applied to the analysis of triphenylboron, which has been produced as a substitute for organotin compounds, in water. Although commercial triphenylboron compounds are produced as pyridinyl complexes, the chemical form in water is supposed to be mainly triphenylboron after liberating pyridine. The triphenylborons were extracted from water with an Empore C18 extraction disk under acidic condition, and the extracts were introduced directly into a liquid chromatograph-mass spectrometer equipped with a negative ion electrospray ionization interface. Identification of the compounds was performed with specific ions produced from the triphenylboron, and a quantitative analysis was carried out using the peak areas. The average recoveries from distilled water, seawater and river water at 0.30 ng/ml were 92.3, 100 and 85.3%, respectively. A detection limit of 0.023 ng/ml for triphenylboron was achieved.     

U(1) gauge-coupled Dirac equation and massless (QED)2 on a finite element

Toward the construction of the gauge theory on a lattice without species doubling, we formulate the U(1) gauge-coupled Dirac equation on a finite element in (d + 1)-dimensional space-time. For massless (QED)₂, we derive the vector current conservation and the axial anomaly. The reproduction of the axial anomaly indicates the resolution of the doubling problem.     

ESR of copper tutton salts around 0.1 K

A remarkable H/T effect in the intensity of ESR absorption is reported for the case of two Cu Tutton salts studied at 9.4 GHz and at temperatures down to 37 mK. Results can be reasonably expressed by the Brillouin function for $\text{S =}\text{1}\text{2}$.     

PSDF of log-amplitude scintillation for 7 μm band laser beam with absorption by water vapour

The power spectral density function (PSDF) of the log-amplitude scintillation for an infrared laser beam was measured experimentally. To investigate the contribution of the absorption and the dispersion that cause the scintillation, we chose 16 wavelengths of infrared light and one wavelength of visible light. It is found that the spectral density of scintillation for the infrared beam does not agree with that for the visible beam, as predicted by Tatarskii's theory in the low-frequency region below 1 Hz. This disagreement between the experiment and the theory in the low-frequency region should be attributed to water vapour absorption.     

Momentum distribution of Hückel π electrons

The momentum distribution and related physical properties are examined for π molecular orbitals (MOs) of a conjugated hydrocarbon system obtained by the empirical Hückel method. Several general rules are derived and the momentum-space aspect of the Hückel π electron theory is clarified.     

Energy-density relations in momentum space. III. Variational aspect

A variational formula for the momentum density is derived by using the Hellmann-Feynman theorem and by introducing a reference system whose Hamiltonian differs only in the kinetic energy part from that of the original system. As simple applications of the present results, the reduced mass correction and the relativistic correction for the hydrogen-like atom are discussed.