Angle-resolved photoemission of the c(2 × 2) and c(3 × 1) oxygen overlayers on Fe(110)

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation has been used to study the band structure of the c(2×2) and (3×1) oxygen overlayers on Fe(110). The symmetries of the O-2p-derived states at the center of the surface Brillouin zone $\text{(}\text{Γ}\text{)}$ were identified using polarized light. At $\text{Γ}$ the p_xp_y- and p_z-derived levels are at about 5.5 and 7.0 eV below the Fermi level, respectively, for both ordered overlayers. The p-states of the c(2×2)-O structure show very little dispersion (?0.1 eV) with $\text{k}{}_{\mathrm{}}$. On the other hand, the c(3×1)-O overlayer exhibits considerable dispersion of ～1.6 eV. The essential features of the measured dispersion are reproduced well by the dispersion predicted in a qualitative way for an isolated c(3×1) oxygen monolayer.     

Synthesis and characterization of nickel(II) complexes with potentially pentadentate macrocyclic ligands having N3O2 donor set

Nickel(II) complexes of N₃O₂ donor macrocycles incorporating 17- to 19-membered macrocyclic rings have been prepared. Physical measurements ind     

Preparation of new bis(oxazoline) ligand bearing non-covalent interaction sites and an application in the highly asymmetric Diels-Alder reaction

New asymmetric bis(oxazoline) (Box) ligand bearing amide group at the oxazoline 4-position, (S,S)-2,2′-methylenebis(4-tert-butylcarbamoyl-2-oxazoline) (1S), was designed and synthesized for selective catalytic reaction. The crystal structure of the ternary copper complex, consisting of 1S and N-benzoyl-N-phenyl-hydroxylamine, demonstrated interligand interactions, such as hydrogen bonding and CH-π interaction. Catalytic performance of the copper complex with 1S was investigated for an asymmetric Diels-Alder reaction using benzylidene-2-acetylpyridine and 1,3-cyclohexadiene (CHD). The reaction product was enantio-pure endo-(pyridin-2-yl)(3-phenylbicyclo[2,2,2]oct-5-ene-2-yl)methanone (BPCD), of which crystal structure was analyzed by the X-ray method. No stereo- and enantio-isomer of BPCD was detected by chiral HPLC analysis. Introduction of hydrogen bonding site into 1S can promote the Diels-Alder reaction even though using poor reactive CHD. Without 1S, this reaction did not give any product. Addition of 2-propanol to this reaction system inhibited the formation of BPCD, indicating that the designed interligand interaction sites, especially hydrogen bonding, play an important role for catalytic performance.     

FT-IR study of the interlamellar water confined in glycolipid nanotube walls

The local hydrogen-bonding environment of water confined in glycolipid nanotubes (LNTs) was investigated by Fourier transform infrared (FT-IR) spectroscopy. Using X-ray diffraction (XRD), we estimated the thickness of an interlamellar water layer, which was confined between the bilayer membranes constructing the walls of the LNTs, to be 1.3 +/- 0.3 nm. FT-IR spectroscopic measurement of the confined water showed an obvious reduction in IR absorption in both the low-energy (around 3000 cm(-1)) and high-energy regions (around 3600 cm(-1)) of the OH stretching band as compared to bulk water. The reduction around 3000 cm(-1) indicated a decrease in the relative proportion of the water molecules with a long-range network structure due to a geometrical restriction. This agrees with the results obtained for other multilamellar systems. On the other hand, the remarkable reduction around 3600 cm(-1), which was not observed in the other systems, indicated the absence of weakly hydrogen-bonded water aggregates due to the effect of sugar headgroups.     

Kationi-sche Polymerisation von Styrolen durch Protons?uren und deren Derivate. 4. Mitt. Homo- und Copolymerisationen von p-substituierten Styrolen mit CF3SO3H

Ohne Zusammenfassung     

Steam reforming of methanol over Ni, Co, Pd and Pt supported on ZnO

Pd/ZnO and Pt/ZnO exhibited anomalously high selectivity for the steam reforming of methanol, when PdZn and PtZn alloys phases were developed. The selectivity decreased over the catalysts having metal phases.     

On first passage time structure of random walks

For continuous time birth-death processes on {0,1,2,…}, the first passage time T⁺_n from n to n + 1 is always a mixture of (n + 1) independent exponential random variables. Furthermore, the first passage time T_0,n+1 from 0 to (n + 1) is always a sum of (n + 1) independent exponential random variables. The discrete time analogue, however, does not necessarily hold in spite of structural similarities. In this paper, some necessary and sufficient conditions are established under which T⁺_n and T_0,n+1 for discrete time birth-death chains become a mixture and a sum, respectively, of (n + 1) independent geometric random variables on {1,2,…};. The results are further extended to conditional first passage times.     

Thermal neutron calibration method using an intense neutron beam from JRR-3M

We have developed a thermal neutron calibration method using a reactor produced neutron beam in JRR-3M of the Japan Atomic Energy Agency. Neutron-induced prompt gamma ray analysis has usually been performed in this beam line. Neutron energy distributions with negligible contributions from epithermal neutrons were measured by a time-of-flight method with a chopper made of ⁶LiF powder. The thermal neutron flux was determined by a gold foil activation method. We found that the thermal neutron beam in JRR-3M was well suited for calibration, neutron detector development or neutron dosimetry.