The effect of annealing on the proton conductivity of Mg-doped α-Al2O3

In order to evaluate the effect of annealing treatment on the proton conductivity of ??-alumina, the electrical conductivity of Mg-doped polycrystalline ??-alumina kept at 1,873?K under various conditions of the surrounding atmosphere and then cooled in the furnace was measured in the temperature range 1,173?C1,473?K. The H⁺/D⁺ isotope effect on the electrical conductivity was also examined under a hydrogen atmosphere at 1,273?K. The protonic conductivity measured at 1,273?K increased with the increase in the activity of oxygen and water vapor in the annealing atmosphere at 1,873?K. It is considered that the solubility limit of magnesium ions in ??-alumina in equilibrium with the small amount of the spinel phase increased with the increase in the activity of oxygen and water vapor at 1,873?K. This enhanced amount of magnesium ions is frozen in a non-equilibrium state to 1,273?K and works as the enriched acceptor dopant for the incorporation of protons.     

Observation of the fast potential change at L-H transition by a heavy-ion-beam probe on JFT-2M

The fast potential change near the separatrix is measured directly at the L-H transition by a heavy-ion-beam probe. The potential changes with two different time scales at the L-H transition triggered by a sawtooth crash: it drops at first with the time scale of 10--100 mus just after the arrival of the heat pulse due to the sawtooth crash. Then, it decreases again at a few 100 mus after the first drop at a time scale of about 200 mus.     

-symmetry for (r,s)-hypergeometric series

Contiguous operators for a two-parameter analogue of hypergeometric series are constructed. These represent a two-parameter quantum enveloping algebra introduced by Takeuchi.     

Control system of stockers in radioisotopes storage room using a personal computer

This paper describes a control system of stockers for radioactive source in storage room at laboratory for tracer experiment. The system is composed of a personal computer, a locker controller, three card readers, a monitor TV, and a video tape recorder (VTR). The personal computer controls other equipment with a registered user's number. When a user inserts an identification card into the card reader, the computer memorizes assigned gate number, the user's number and the time; it processes those data and prints out a document. The locker controller releases the electric key of user's locker which is designated by the computer. The VTR records the person entering into the storage room to identity if he uses his card. This system proved to effectively prevent intrusion into the storage room of an unregistered person or to use carelessly other user's source; in addition it can record precisely the stock of radioactive source.     

Retrieving reflection responses by crosscorrelating transmission responses from deterministic transient sources: application to ultrasonic data

By crosscorrelating transmission recordings of acoustic or elastic wave fields at two points, one can retrieve the reflection response between these two points. This technique has previously been applied to measured elastic data using diffuse wave-field recordings. These recordings should be relatively very long. The retrieval can also be achieved by using deterministic transient sources with the advantage of using short recordings, but with the necessity of using many P-wave and S-wave sources. Here, it is shown how reflections were retrieved from the cross correlation of transient ultrasonic transmission data measured on a heterogeneous granite sample.     

Enhanced catalytic activity on titanosilicate molecular sieves controlled by cation-π interactions

A new class of heterogeneous catalytic systems utilizing cation-guest interactions was designed based on microporous titanosilicate molecular sieves. Introducing heavier alkali metal cations on ion-exchange sites of the framework resulted in a significant enhancement of the catalytic activity for oxidation of cyclohexene and styrene, whereas such an enhancement was not observed in oxidation of cyclohexane without π systems. Distinct relationships between the catalytic activities and intermolecular interaction energies which were determined by IR spectroscopic and computational approaches clearly evidenced the predominance of the cation-π interaction in this catalytic system.     

He I ultraviolet photoelectron spectroscopy of benzene and pyridine in supersonic molecular beams using photoelectron imaging

We performed He I ultraviolet photoelectron spectroscopy (UPS) of jet-cooled aromatic molecules using a newly developed photoelectron imaging (PEI) spectrometer. The PEI spectrometer can measure photoelectron spectra and photoelectron angular distributions at a considerably higher efficiency than a conventional spectrometer that uses a hemispherical energy analyzer. One technical problem with PEI is its relatively high susceptibility to background electrons generated by scattered He I radiation. To reduce this problem, we designed a new electrostatic lens that intercepts background photoelectrons emitted from the repeller plate toward the imaging detector. An energy resolution (ΔE/E) of 0.735% at E = 5.461 eV is demonstrated with He I radiation. The energy resolution is limited by the size of the ionization region. Trajectory calculations indicate that the system is capable of achieving an energy resolution of 0.04% with a laser if the imaging resolution is not limited. Experimental results are presented for jet-cooled benzene and pyridine, and they are compared with results in the literature.     

Fluorescent trimethyl-substituted naphthyridine as a ligand for C-C mismatch detection in CCG trinucleotide repeats

We report on the selective binding of 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) to C-C mismatch present in the hairpin structures of (CCG)(n) trinucleotide repeats that are associated with neurological diseases; this binding is accompanied by significant fluorescence quenching of ATMND.     

Spatiotemporally controlled contraction of micropatterned skeletal muscle cells on a hydrogel sheet

We have developed gel sheet-supported C(2)C(12) myotube micropatterns and combined them with a microelectrode array chip to afford a skeletal muscle cell-based bioassay system. Myotube line patterns cultured on a glass substrate were transferred with 100% efficiency to the surface of fibrin gel sheets. The contractile behavior of each myotube line pattern on the gel was individually controlled by localized electrical stimulation using microelectrode arrays that had been previously modified with electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT). We successfully demonstrated fluorescent imaging of the contraction-induced translocation of the glucose transporter, GLUT4, from intracellular vesicles to the plasma membrane of the myotubes. This device is applicable for the bioassay of contraction-induced metabolic alterations in a skeletal muscle cell.     

Imaging of enzyme activity by scanning electrochemical microscope equipped with a feedback control for substrate-probe distance

The enzymatic activity of diaphorase (Dp) immobilized on a solid substrate was characterized using a scanning electrochemical microscope (SECM) with shear force feedback to control the substrate-probe distance. The shear force between the substrate and the probe was monitored with a tuning fork-type quartz crystal and used as the feedback control to set the microelectrode probe close to the substrate surface. The sensitivity and the contrast of the SECM image were improved in the constant distance mode (distance, 50 nm) with the shear force feedback compared to the image in the constant height mode without the feedback. By using this system, the SECM and topographic images of the immobilized diaphorase were simultaneously measured. The microelectrode tip used in this study was ground aslant like a syringe needle in order to obtain the shaper topographic images. This shape was also effective for avoiding the interference during the diffusion of the enzyme substrates.