Electron Spin Resonance in Pr0.65Ca0.35MnO3

The magnetic behavior of the distorted perovskite manganese, Pr_0.65Ca_0.35MnO₃ was studied by X-band electron spin resonance for powder samples. We observed the onset of the charge-ordered state at T _CO215 K, the antiferromagnetic transition with the peak of the ESR linewidth, H _p–p at T _AF180 K and the canted antiferromagnetic transition at T _CAF125 K associated with the abrupt increase of both the effective magnetization and H _p–p . Below 90 K, the absorption intensity profile becomes weakened with decreasing temperature suggesting the existence of some kind of magnetic disorder below 90 K, which is responsible for a part of evidence of the existence of the spin-glass state as has been proposed by Yoshizawa et al., Phys. Rev. B 52, 1689 (1996).     

Effects of crystalline form on the tableting compression mechanism of phenobarbital polymorphs

The effects of the polymorphic form on the compression mechanism of forms A, B, and F of phenobarbital were investigated using a compression simulator, mercury porosimetry, X-ray diffraction analysis, BET gas absorption method, and scanning electron microscopic (SEM) photography. The order of tablet hardness obtained from all phenobarbital polymorphs was form A ≥ form B ≥ form F in accordance with that of the specific surface area. The Cooper and Eaton method was applied to evaluate two individual compression processes: particle rearrangement (phase I) and fragmentation and/or deformation (phase II). The parameters for compression processes were calculated using a nonlinear regression analyses program, and the compression energies of phases I and II were calculated from these parameters. The relationship between specific surface area after compression and compression energy at phase I showed a good linear correlation, but their ratio did not. In contrast, the specific surface area ratio showed a linear relationship with the compression energy on phase II, but again the ratio of these two parameters did not. The tablet hardness showed a linear relationship with the specific surface area ratio, but not with the specific surface area. Again, the ratio of these two parameters did not show a linear relationship.     

Photo-Induced Effect of the Electron-Spin Resonance on the Charge-Ordered State in Pr0.65Ca0.35MnO3

Electron-spin resonance (ESR) for the charge-ordered state in well-characterized Pr_0.65Ca_0.35MnO₃ exhibited significant change of both the absorption profile and the effective spin susceptibility upon injection of laser light with photon energy of 1.17 eV provided by Nd-YAG laser. The increase of the effective spin susceptibility was clearly found out thanks to the injection of photons in the temperature range 90 K–80 K, which is below the transition temperature from the antiferromagnetic charge ordered state to the canted antiferromagnetic spin alternation state, T _CAF125 K. The temperature dependence of the change of the ESR profile excludes the possibility of heating by laser light. The present result suggests that a kind of photo-induced insulator–metal transition may occur due to propagation of the delocalized carriers via probable double exchange interaction in the charge-ordering collapsed state created by the injection of photons.     

Thickness dependence of H2 gas sensor in amorphous SnQx films prepared by ion-beam sputtering

Amorphous SnO_x films were deposited by ion-beam sputtering on sintered alumina substrates. Amorphous film sensors were prepared by annealing the films at 300° C for 2 h in air. The thickness dependence of resistivity and hydrogen gas sensitivity were measured at 150° C over the thickness range 1 to 700 nm. A resistivity maximum was observed in ultrathin films. Resistivity increased by three orders of magnitude with increasing film thickness from 0.9 to 7.4 nm and then decreased by five orders of magnitude from 7.4 to 35 nm. Ultrathin film sensors showed sensitivity maxima around a thickness of 10 nm. Sensitivity and resistivity of ultrathin films were significantly influenced by the thermal expansion coefficient and the surface state of the substrate.     

FreeWalk: a 3D virtual space for casual meetings

A meeting environment for casual communication in a networked community, FreeWalk provides a 3D common area where everyone can meet and talk freely. FreeWalk represents participants as 3D polygon pyramids, on which their live video is mapped. Voice volume remains proportional to the distance between sender and receiver. For evaluation, we compared communications in FreeWalk to a conventional desktop videoconferencing system and a face-to-face meeting     

Development of new‐type outdoor termination using composite insulator with SF6 gas: Commercial use for 77‐kV transmission lines and development for 154‐kV XLPE cable

Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF₆ gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF₆ gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511     

Mercuric chloride induces increases in both cytoplasmic and nuclear free calcium ions through a protein phosphorylation-linked mechanism

The mechanism of the lymphocyte stimulatory action of sulfhydryl group-reactive mercuric ions was studied with respect to its potential ability to induce a protein tyrosine phosphorylation-linked signal for mobilization of free Ca2+ into cytoplasm and nucleus of the cell. Exposure of human leukamic T cell line (Jurkat) cells to high (1 mM) and low (0.01 mM) concentrations of HgCl2 induced tyrosine phosphorylation of multiple proteins in a concentration-dependent manner. Confocal microscopy directly visualized the time course localization of Ca2+ inside the cells after exposure to HgCl2. The onset and level of Ca2+ mobilization following HgCl2 exposure were in parallel to those of protein tyrosine phosphorylation. Interestingly, by either concentration of HgCl2, Ca2+ was mobilized in both cytoplasm and nucleus almost simultaneously, and the level of Ca2+ mobilization in the nucleus was more than that in the cytoplasm. All the HgCl2-mediated Ca2+ mobilization was prevented by addition of protein kinase inhibitor staurosporin prior to HgCl2. These results suggest that heavy metal stress triggers a protein tyrosine phosphorylation-linked signal that leads to a nuclear event-dominant Ca2+ mobilization.     

A 250-Mb/s/pin, 1-Gb double-data-rate SDRAM with a bidirectionaldelay and an interbank shared redundancy scheme

This paper describes three circuit technologies indispensable for high-bandwidth multibank DRAM's. (1) A clock generator based on a bidirectional delay (BDD) eliminates the output skew. The BDD measures the cycle time as the quantity charged or discharged of an analog quantity, and replicates it in the next cycle. This achieves a 0.18-mm ², two-cycle-lock clock generator operating from 25 to 167 MHz with a 30-ps resolution. (2) A quad-coupled receiver eliminates the internal skew caused by the difference between a rise input and a fall input by 40%. (3) An interbank shared redundancy scheme (ISR) with a variable unit redundancy (VUR) efficiently increases yield in multibank DRAM's. The ISR allows redundancy match circuits to be shared with two or more banks. The VUR allows the number of units replaced to be variable. These circuit technologies achieved a 250-Mb/s/pin, 8-bank, 1-Gb double-data-rate synchronous DRAM     

Experimental and analytical studies of the thermal stratification phenomenon in the outlet plenum of fast breeder reactors

Water and sodium experiments were conducted with scaled models to study the in-vessel thermal stratification. The models simulate the outlet plenum in a loop-type LMFBR with an inner barrel and a closed-type UIS (upper instrumentation structure). An examination of the threshold for thermal stratification, the rising rate of the stratification interface, and the flow regime above the interface has been conducted and is reported in the present paper. In parallel, the phenomenon in the experiments has been evaluated with the multi-dimensional analysis.