Change of electronic structure in Ca2RuO4 induced by orbital ordering

Optical conductivity spectra sigma(omega) were used to investigate the effect of orbital ordering on the electronic structure of Ca2RuO4. Our LDA+U calculation predicts Ru 4d(xy) ferro-orbital ordering at the ground state, and well explains the present sigma(omega) as well as the reported O 1s x-ray absorption spectra. Variation of temperature (T) causes a large change of spectral weight over several eV as well as collapse of a charge gap accompanied by elongation of the c-axis Ru-O bond length. These results clearly indicate that the d(xy) orbital ordering plays a crucial role in the metal-insulator transition and the T-dependent electronic structure on a large energy scale.     

Photochromic radical compounds based on a naphthopyran system

[reaction: see text] Naphthopyran derivatives with aminoxyl substituents (4a,b) gave the corresponding open-formed isomers (5a,b) by irradiation, which could be changed back to the starting closed-formed naphthopyrans by the treatment with SiO(2) as a catalyst. The tuning of intermolecular magnetic interactions between the isomer couples was found to be possible in these reversible systems.     

Reduction of ion thermal diffusivity associated with the transition of the radial electric field in neutral-beam-heated plasmas in the large helical device

Recent large helical device experiments revealed that the transition from ion root to electron root occurred for the first time in neutral-beam-heated discharges, where no nonthermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. A clear reduction of ion thermal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory when the neoclassical ion loss is more dominant than the anomalous ion loss.     

Observation of the "self-healing" of an error field island in the large helical device

It was observed that the vacuum magnetic island produced by an external error magnetic field in the large helical device shrank in the presence of plasma. This was evidenced by the disappearance of flat regions in the electron temperature profile obtained by Thomson scattering. This island behavior depended on the magnetic configuration in which the plasmas were produced.     

Dispersion resulting from phase and amplitude errors in arrayed-waveguide grating multiplexers-demultiplexers

We report dispersion resulting from phase and amplitude errors in arrayed-waveguide grating (AWG) multiplexers-demultiplexers. We measure the phase- and amplitude-error distributions of two different types of AWG and discuss their effects on the dispersion. The results show that the origin of the dispersion in the AWG is the low-order Fourier components of the symmetric phase and the antisymmetric amplitude errors. We also discuss the dependence of the dispersion on the passband shape in the presence of the same fabrication errors.     

Real three-dimensional microstructures fabricated by photopolymerization of resins through two-photon absorption

Effective energy windows for two-photon absorption (TPA) photopolymerization of resins were investigated and, with a properly selected laser pulse energy, exquisite three-dimensional (3D) microstructures with submicrometer spatial resolution were achieved. The results show the inherent utility of TPA in the fabrication of real 3D patterns. In particular, we propose and utilize a resin pre-exposure technique by which freely movable components affixed to an axle are built, demonstrating a new application of TPA in laser microfabrication.     

Peumusolide A, unprecedented NES non-antagonistic inhibitor for nuclear export of MEK

A new polyketide peumusolide A was disclosed as an unprecedented NES non-antagonistic inhibitor for nuclear export of MEK, a promising scaffold for antitumor agents with novel mechanism of action, from Peumus boldus Molina. The absolute stereostructure as well as optical purity was established by use of the two synthesized enantiomeric model lactones. In addition, the Δε values in their CD spectra were demonstrated to be the conclusive index for determination of not only configuration at C-3 but also optical purity of natural congeneric polyketides. Peumusolide A was revealed to show NES non-antagonistic action by the biotinylated probe and to inhibit proliferation of MEK-activated tumor cells selectively.     

Printed circuit rat-race-type directional couplers for larger power-split ratio

Two different types of 5/2-wavelength rat-race-type directional couplers with a remarkably increased power-split ratio for a realizable ring-impedance, in particular which are useful for millimeter-wave circuits suffering from the severe restriction on the usable impedance range, are described. Experimental corroboration is provided in the microwave region (at 8 GHz).