Rapid sensing of trace ionic substances with the novel porous monolith type ion exchanger

Biological and chemical sensor with a rapid response in microlevel test is required for health and environmental monitor. A novel sensing due to porous ion exchanger with three-dimensional acceptor has been first attempted to develop a high-performance sensor. This porous monolith type ion exchanger has an open-cellular monolith structure with 5–50-μm diameter pores. The trace amount of inorganic ions dissolved in aqueous solutions can be quantitatively determined with the impedance given by the monolith, which attracts and adsorbs the ions rapidly. We have succeeded in detecting ions with a concentration as low as 10⁻⁷ mol. The porous ion exchanger has a potentiality as a high-performance device for biological and chemical sensing. POLYM. ENG. SCI., 47:1666–1670, 2007. © 2007 Society of Plastics Engineers     

Oxidative coupling of methane applying a solid oxide fuel cell system

A fuel cell system using yttria-stabilized zirconia as a solid electrolyte was applied to the oxidative coupling of methane. The most active and selective catalyst was BaCO₃ deposited on Au-electrode (anode). Optimum conditions for the reaction were examined. The pressure of methane at the anode and that of oxygen at the cathode should be high as much as possible. The optimum temperature was 1073 K. Several advantages of the method are described.     

Nuclear analysis of a laser fusion reactor,SENRI-I

A neutronic analysis of the laser-driven inertial-confinement fusion reactor SENRI-I is presented. Three-dimensional Monte Carlo calculations were performed to examine the effects of laser beam ports on the flux distribution, tritium breeding ratio, thermal energy deposition in the blanket, and radiation streaming. A Monte Carlo code was also used for the time-dependent radiation-damage analysis accounting for the time of the flight spread of neutrons and the results are compared to the analysis for the HIBALL design. Induced radioactivity was estimated, based on the one-dimensional transport calculation and depletion analysis. The calculated results reveal the advantages of the SENRI-I design with a thick Li layer compared to other reactor systems employing a dry-wall scheme.     

Calculation of magnetic near field generated by the contact discharge of an ESD gun

An ESD (electrostatic discharge) testing is specified in the IEC 61000‐4‐2, in which the detailed waveform of the discharge current injected by an ESD gun is prescribed. However, due to lack of understanding of the discharge process, it is difficult to confirm whether or not the IEC current waveform can be injected onto actual equipment. We thus previously proposed an equivalent circuit model for the ESD gun based on its geometrical structure, and showed decisive factors for the discharge current. In this study, in order to confirm the feasibility of the above equivalent circuit model, we measured with a 6‐GHz wide‐band digital oscilloscope the discharge current through an SMA connector and the resultant magnetic near field for the contact discharge of an ESD gun. As a result, we found that both measured waveforms approximately agree with those calculated from our equivalent circuit model. We then measured with respect to charge voltages the magnetic near fields for the contact discharge of the ESD gun to the ground, which revealed that the measured waveform around the first peak is in fair agreement with the calculated one. Furthermore, we found that the magnetic field peak increases with increasing charge voltage, whose dependence can be predicted from our equivalent model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(1): 17–24, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20194     

The characteristics and measuring technique of refractory dissolved organic substances in urban runoff.

It is considered that refractory dissolved organic substances have caused an increase in the COD concentration in Lake Biwa in recent years. We investigated the organic matter in the first flush of stormwater runoff from a road in the watershed area of the lake, and studied the possibility of improvement in the water environment from that aspect. After percolating the stormwater through soil, we analyzed organic substances fractionated by using GPC-TC. And we examined the effect of removal of organic substances by comparing the peak height before and after percolation. In the result of the experiments, we found that soil infiltration reduced the refractory dissolved organic substance and we successfully designed a system for a simple and easy experimental facility to treat urban runoff.     

SAW velocity measurement of crystals and thin films by the phasevelocity scanning of interference fringes

We present principle and application of a novel noncontact velocity measurement of surface acoustic waves (SAW) on crystals and thin films using laser interference fringes scanned at the phase velocity of SAW. The scanning interference fringes (SIF) are produced by intersecting two laser beams with a frequency difference. The SAW velocity within the laser beam spot is measured as the ratio of observed SAW frequency and predetermined wave number of the SIF. The frequency measurement can be quite precise because of a large number of generated SAW carriers and amplitude enhancement effect. The SAW velocity measurement is free from the water loading effect accompanying the leaky SAW measurements. This principle was successfully applied to evaluate Si ₃N₄ and SiO₂ films deposited on Si (001) surface     

Ab initio molecular orbital calculations of the NMR chemical shieldings for mannose and mannobiose

The ¹³C and ¹H NMR shielding constants for -methylmannose and -methylmannobiose have been calculated using the ab initio gauge-including atomic orbital (GIAO) method to study the conformational dependencies of the NMR chemical shifts of the sugars. The molecular structures were fully optimized using B3LYP/6-31G^* and the NMR shielding constants were calculated at both Hartree–Fock (HF) and density functional (DF) levels of theory with various kinds of basis sets. The values determined using the B3LYP hybrid functional were a little closer to those obtained experimentally than those determined at the HF level. Both, HF and B3LYP with the 6-311+G(2d,p) basis were found to give a very good correlation between the experimental and calculated shielding constants, especially for ¹³C.     

Dual-wavelength optical head with a wavelength-selective filter for 0.6- and 1.2-mm-thick-substrate optical disks

A dual-wavelength optical head, believed to be new in design, for 0.6- and 1.2-mm-thick-substrate optical disks was developed by use of 650- and 780-nm-wavelength light and a wavelength-selective filter, which reduces the spherical aberration that is due to the difference in substrate thicknesses and restricts the numerical aperture for 780-nm-wavelength light. According to this configuration, both high light power efficiency and wide image field characteristics are obtained, which are suitable not only for read-only but also for recordable or rewritable optical disk systems. A reading operation for a digital video disc and for a compact disc and a recording operation for a phase change optical disk were successfully demonstrated.