Terahertz radiation by an ultrafast spontaneous polarization modulation of multiferroic BiFeO3 thin films

Terahertz (THz) radiation has been observed from multiferroic BiFeO3 thin films via ultrafast modulation of spontaneous polarization upon carrier excitation with illumination of femtosecond laser pulses. The radiated THz pulses from BiFeO3 thin films were clarified to directly reflect the spontaneous polarization state, giving rise to a memory effect in a unique style and enabling THz radiation even at zero-bias electric field. On the basis of our findings, we demonstrate potential approaches to ferroelectric nonvolatile random access memory with nondestructive readability and ferroelectric domain imaging microscopy using THz radiation as a sensitive probe.     

An alternative treatment of lifting-line theory as a perturbation problem

The purpose of the present paper is to show that lifting-line theory can be easily derived by applying the method of asymptotic expansions to the integral equation given by lifting-surface theory, in contrast to Van Dyke's paper [1] in which lifting-line theory is derived by applying the method of matched asymptotic expansions to a partial differential equation. Moreover, the present paper shows that there is an error in Van Dyke's paper about the third-order inner approximation, and the corrected formula about the circulation is obtained.

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Zusammenfassung In dieser Arbeit wird eine neue theoretische Untersuchung der Theorie der tragenden Linie beschrieben. Sie geht von der Tragflächentheorie aus mit Hilfe von asymptotischen Reihenentwicklungen. Es wird gezeigt, dass die Traglinientheorie in der Behandlung von Van Dyke [1] einen Fehler in der inneren Entwicklung dritter Ordnung enthält, und die richtige Form für den Auftrieb wird berechnet.

     

Optical parametric amplification of a supercontinuum in a gas

Amplification of supercontinuum light via four-wave optical parametric amplification in a gas-filled hollow fiber is investigated. By pumping with a femtosecond pulse in the near-infrared, amplification was observed in the wavelength range 500–700 nm, with an amplification gain up to 100. The amplification bandwidth obtained here supports sub-10-fs pulse durations. The wavelength and gas-pressure dependence of the amplification gain in this regime significantly differ from those predicted from only the linear phase mismatch. The nonlinear phase mismatch, arising from nonlinear phase modulations induced by a pump pulse, dominates the features observed for the amplification, i.e., a low phase-matching pressure and an amplification gain depending on wavelength. To investigate the effect of phase modulations on the parametric amplification, numerical analysis and simulations are used to reproduce the measured wavelength dependence of the amplification gain.     

Detection of organic gases using TiO2 nanotube-based gas sensors

We fabricated porous gas sensing films composed of TiO₂ nanotubes prepared by a hydrothermal treatment for the detection of organic gases, such as alcohol and toluene. The morphology of the sensing films was controlled with a ball-milling treatment and calcination at high temperature to improve the sensitivity of the films. The sensor using nanotubes with the ball-milling treatment exhibited the improved sensor responses to toluene at 500oC. The results obtained indicated the importance of the microstructure control of sensing layers in terms of particle packing density, pore size distribution, and particle size and shape for detecting large sized organic gas molecules.     

Optical magnetoelectric effect in a submicron patterned magnet

The optical magnetoelectric effect, which is a nonreciprocal directional dichroic response, has been demonstrated in a submicron patterned magnet by monitoring the diffracted visible or near-infrared light intensity. An artificial magnetic superstructure is composed of chevron shaped ">" islands made of the ferromagnetic permalloy Ni(80)Fe(20) with a pitch of 1 microm on silicon substrate, in which both space inversion and time reversal symmetry are broken simultaneously. On the basis of the light-polarization angle and magnetic field H dependence, and also comparing the results with the those of the submicron square patterns, we show that the optical magnetoelectric effect emerges as the finite change (approximately 10(-3) at room temperature in H of 500 Oe) of the diffracted intensity.     

Immunochemical analysis of a photoreceptor protein using anti-IP3 receptor antibody in the unicellular organism, Blepharisma

The blepharismin-200 kD protein complex of the ciliated protozoan Blepharisma is a novel type of photosensor responsible for the step-up photophobic response of the cell. In immunoblotting assays, the 200 kD protein is weakly cross-reacted with anti-inositol triphosphate receptor antibody (anti-IP3 R antibody). Indirect immunofluorescence assays show that the pigment granules in which the blepharismin-200 kD protein complex is localized are labelled by anti-IP3 R antibody. When the anti-IP3 R antibody or antisense oligonucleotide for IP3 receptor is introduced into the living cells of Blepharisma, both the photosensitivity of the cells and content of blepharismin-200 kD protein are reduced. The results suggest that the photoreceptor 200 kD protein is possibly an IP3 receptor-like protein.     

Production of Bio-Ethanol by Integrating Microwave-Assisted Dilute Sulfuric Acid Pretreated Sugarcane Bagasse Slurry with Molasses

Sugarcane bagasse (SCB) and molasses, known as carbohydrate-rich biomass derived from sugar production, can serve as feedstock for bio-ethanol production. To establish a simple process, the production of bio-ethanol through integration of whole pretreated slurry (WPS) of SCB with molasses was investigated. The results showed that microwave-assisted dilute sulfuric acid pretreatment reduced the formation of toxic compounds compared to a pretreatment process involving “conventional heating”. Pretreatment at 180 ^oC with 10% w v^?1 solid loading and 0.5% w v^?1 H₂SO₄ was sufficient to achieve efficient enzymatic saccharification of WPS. By conducting separate hydrolysis and fermentation (SHF), an ethanol yield of 90.12% was obtained from the mixture of WPS and molasses, but the ethanol concentration of 33.48 g L^?1 was relatively low. By adopting fed-batch SHF, the ethanol concentration reached 41.49 g L^?1. Assuming that the molasses were converted to ethanol at an efficiency of 87.21% (i.e., ethanol was obtained from fermentation of molasses alone), the ethanol yield from WPS when a mixture of WPS and molasses was fermented was 78.30%, which was higher than that of enzymatic saccharification of WPS (73.53%). These findings suggest that the production of bio-ethanol via integration of WPS with molasses is a superior method.

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A prodrug of NMDA/glycine site antagonist, L-703,717, with improved BBB permeability: 4-acetoxy derivative and its positron-emitter labeled analog

4-Acetoxy derivative (1) of L-703,717, a high-affinity (IC50=4.5 nM) antagonist for the glycine site of NMDA receptors, was synthesized and its brain uptake was examined using a carbon-11 labeled analog ([11C]1). Initial radioactivity in the brain after intravenous injection of [11C]1 was a 2-fold that of [11C]L-703,717 in mice. Rapid bioconversion of [11C]1 into [11C]L-703,717 was demonstrated by metabolite analyses of rat brain after [11C]1 injection. Ex vivo autoradiography of [11C]1 in rat brain showed the same cerebellar localization of radioactivity as [11C]L-703,717. These results indicate that 1 is a promising pharmacological tool as a prodrug of L-703,717 with improved BBB permeability.