Interferometric two-photon photoemission correlation technique and femtosecond wet-electron dynamics at the TiO (110) surface

The femtosecond time-resolved two-photon photoemission (TR-2PP) and the ultra high vacuum (UHV) surface science techniques are integrated to investigate the elec- tronic structures and the interfacial electron transfer dynamics at the atomically ordered adsorbate overlayers on TiO₂ single- crystalline surfaces. Our research into the CH₃OH/TiO₂ system exhibits complex dynamics, providing abundant informa- tion with regard to electron transport and solvation processes in the interfacial solvent structures. These represent the fundamentally physical, photochemical, and photocatalytic reactions of protic chemicals covered with metal-oxides.     

Two new monoterpene peroxide glycosides from Aster scaber.

The aerial part of Aster scaber Thunb. (Asteraceae) yielded two new monoterpene peroxide glycosides, (3S)-3-O-(3',4'-diangeloyl-beta-D-glucopyranosyloxy)-7-hydroperoxy-3,7-dimethylocta-1,5-diene (1) and (3S)-3-O-(3',4'-diangeloyl-beta-D-glucopyranosyloxy)-6-hydroperoxy-3,7-dimethylocta-1,7-diene (2), and five known compounds, alpha-spinasterol (3), germacra-4(15),5,10(14)-triene-1-beta-ol (4), 7-methoxy-4(15)-oppositen-1-beta-ol (5), 6alpha-methoxy-4(15)-eudesmane-1beta-ol (6) and alpha-spinasterol 3-O-beta-D-glucopyranoside (7). The structures were established by chemical and spectroscopic methods.     

Capillary electrochromatography using fibers as stationary phases.

Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method.     

Utilization of microgravity to improve the crystal quality of biologically important proteins: chaperonin-60, GrpE, B-subunit of V-type ATPase, and MIF

Protein crystallization experiments under microgravity were performed by using commercial vapor diffusion apparatus (CVDA) hardware on the STS-84 shuttle mission. Chaperonin-60, GrpE, the B subunit of V-type ATPase, and the selenomethionine substituted proteins of macrophage migration inhibitory factor (MIF) were selected as target proteins. The results indicate that microgravity positively affected their crystal growth, supporting the practical utilization of microgravity for the protein structure determination.     

Effects of aluminum impurity on the structural relaxation in silica glass

To elucidate effects of Al impurity on the glass-forming process in silica glass, the structural relaxation in Al-containing silica glass, with alkali ions of only trace levels, was investigated by observing the fictive temperature. The fictive temperature was determined by infrared (IR) absorption analysis. Al, even at concentrations lower than 10 wtppm, increases the relaxation time and the activation energy of the -relaxation. It also suppresses the sub-relaxational process due to OH ions. These results indicated that Al should have other effects on structural relaxation than alkali–aluminate complex formation, as has been thought to be the cause for an increase in the -relaxation time and thus the viscosity of silica glass. Furthermore, the structural relaxation does not merely depend on the number of non-bridging oxygen atoms in the glass network.     

Modularity of a Certain Calabi-Yau Threefold

 The Langlands program predicts that certain Calabi-Yau threefolds are modular in the sense that their L-series correspond to the Mellin transforms of weight 4 newforms. Here we prove that the L-function of the threefold given by is , the unique normalized eigenform in .     

Laboratory Microwave Spectroscopy of Interstellar Molecules

Abstract

Modern radio astronomy has revealed that various kinds of molecules exist in ther very cold region between stars: interstellar space. An electromagnetic wave with a wavelength of a few centimeters to 1 mm corresponds in energy to a few to ten degrees of Kelvin. A molecule having its spectrum in this energy region provides us with valuable information about the low-energy environment where the molecule exists. New information provided by radio astronomy has rarely been     

Low-temperature growth of high-Tc superconducting films by plasma-enhanced metal-organic chemical vapor deposition

Plasma-enhanced MOCVD in which metal-organic compounds are sublimated directly into the growth chamber is studied for the first time as a new low-temperature process for growing superconducting YBa₂Cu₃O-_-x thin films. Y(THD)₃, Ba(THD)₂, Cu(THD)₂ and oxygen are used as metal sources and oxydizing agent. Emission spectroscopy reveals that activated metal-organic compounds and activated oxygen species are present during film growth. Superconducting YBa₂Cu₃O_7-x films whose zero-resistivity temperature are 50 K and 82 K are grown at 550°C and 600°C.     

Defect-effects on the photoluminescence of ZrO2 bulk,film and nanocrystals

The photoluminescence (PL) properties of ZrO₂ have been measured at different temperatures between 7 and 300 K, using various kinds of ZrO₂ specimens: bulk crystal melt-grown by a large solar furnace, thermally oxidized zirconium plate (ZrO₂ film crystal on Zr ) and nanocrystals (surface area: 35–45m²/g, diameter: 20–30 nm). The results clarify the deep and shallow energy level structures in the energy gap. Reversible UV-laser-light-induced spectral changes are observed for all of the specimens in different specimen-atmospheres (vacuum and O₂ gas). The results elucidate the defect-effects of the PL properties and the PL enhancement mechanism in ZrO₂ nanocrystals.