Preliminary investigation of the supply of chemical species to an aqueous solution using a hydrogen-oxygen flame

A new method of supplying radical species to aqueous solutions using a hydrogen-oxygen flame is investigated. When a hydrogen-oxygen flame is directed on the surface of an aqueous solution, hydroxyl radicals (*OH) produced in the flame are extracted into the aqueous phase. The presence of *OH in the aqueous solution was confirmed by electron paramagnetic resonance with spin trapping using 5,5-dimethyl-1-pyrroline-N-oxide. The extraction of *OH into the aqueous solution was monitored using a quantitative analysis of hydrogen peroxide (H2O2). The effects of the hydrogen and oxygen gas flow rates, hydrogen/oxygen ratio, and atmosphere on H2O2 formation were studied. When the hydrogen-oxygen flame blew on a phosphate buffer solution (pH 6.7) under an Ar atmosphere, the concentration of H2O2 increased with the blowing time of the flame and the flow rate of hydrogen gas. Under air, nitrate and nitrite ions were formed in the aqueous phase in addition to H2O2, and the H2O2 concentration was lower than that under argon. The application of this new method to an aqueous solution of Cu(II)-ethylenediaminetetraacetic acid (EDTA) caused a remarkable decrease in the concentration of Cu(II)-EDTA and total organic carbon.     

Investigation on sensitivity of a polymer/carbon nanotube composite strain sensor

Extensive numerical simulation and experimental measurements have been conducted to understand the effects of processing parameters and material properties on sensor sensitivity in polymer/carbon nanotube (CNT) composite sensors. The numerical simulation was based on an improved three-dimensional statistical resistor network model incorporating the tunneling effect between the neighbouring nanotubes, and a fiber reorientation model. The behaviors of a sensor subjected to both tensile and compressive strains were investigated. Both numerical and experimental results indicate that a higher tunneling resistance or higher ratio of the tunneling resistance to the total resistance of the sensor leads to a higher sensor sensitivity. Processing conditions and material properties, such as weight fraction, diameter and conductivity of CNTs, curing temperature, mixing rate and barrier height of polymer matrix all play a role in determining the sensor sensitivity.     

Magnetic field effect on the photocarriers in self-assembled hexabenzocoronene nanotubes

By means of the integral mode time-of-flight measurement of the drift motion of the photoinjected charge at room temperature, we observed magnetic field effect (MFE) on the photocharge in self-assembled nanotube of hexabenzocoronene (HBC) at the configurations where the magnetic field is parallel and perpendicular to the electric field. The detected MFEs are interpreted in terms of two mechanisms that are caused by the fast charge transportation (Hall effect) and the spin selective recombination (electron–hole (e–h) pair mechanism). A high mobility in the nanotubes of π-stacked HBC was implied from the Hall data. The time dependence of the low field MFE due to the e–h pair mechanism clarified the recombination from both the singlet and triplet e–h pairs with the initial rate of ～10⁸ s^?1.     

Double ionization energy spectra of small alkali-metal clusters

In this article, we calculate the spectra of the double ionization energy (the energy required for adding two electrons to the neutral system) of small alkali-metal clusters (K₂ and Li₂) including the effect of electron–electron short-range correlation by adding two one-particle energies within the GW approximation and taking into account the electron–electron repulsive interaction effectively.     

Application of self-deconvolution method to shift-and-add solar imaging

A shift-and-add (SAA) operation is conducted to reconstruct a high-spatial-resolution image from atmospherically degraded solar images. The self-deconvolving data reconstruction algorithm is used to augment high-spatial-frequency components in solar speckle images and rectify the background component that results from the SAA operation. Self-deconvolved solar speckle images are shift and added and the resulting image shows high-spatial-resolution features.     

PON with Automatic Protection switching for high reliable communication

PON (Passive Optical Network) permits the economical deployment of FTTH (Fiber to the Home) networks by sharing a single optical subscriber line among multiple subscribers. Especially since 2002, the deployment of PON systems has grown rapidly. This paper introduces the current status of FTTH in Japan then proposes a redundant optical access system with APS (Automatic Protection Switching) over PON which enables PONs for FTTBus (Fiber to the Business).     

Microwave magnetoresistance in Ge:Mn nanowires and nanofilms

The Lorentzian and spin-scattering components of magnetoresistance were found and distinguished in Ge:Mn thin films. The suppression of microwave magnetoresistance by the limitation of the dimensionality of Ge nanowires doped with Mn has been revealed. Spin-wave resonance in the long-ordered magnetic state and ferromagnetic resonance in GeMn clusters have been detected.     

Voltage fluctuation compensator for Shinkansen

In AC electric railways, three‐phase voltage is changed into the single‐phase circuit of two circuits with the Scott‐connected transformer. If unbalancing of the load between single‐phase circuits becomes large, voltage fluctuation becomes large on the three‐phase side. Railway static power conditioner (RPC) was developed for the purpose of controlling voltage fluctuation on the three‐phase side. An RPC is comprised of a pair of self‐commutated PWM inverters. These inverters connect the main phase and teaser feeding buses, coupled with a DC side capacitor such as a back‐to‐back (BTB) converter. In this way, the two self‐commutated inverters can act as a static var compensator (SVC) to compensate for the reactive power and as an active power accommodator from one feeding bus to another. 20 MVA/60 kV RPCs started commercial operation in 2002 at each two substations on the newly extended Tohoku Shinkansen for compensating voltage fluctuation on the three‐phase side caused by traction loads, absorbing harmonic current. The results of operational testing indicate that an RPC can accommodate single‐phase loads such as those of PWM‐controlled Shinkansen and thyristor phase‐controlled Shinkansen, and handle the exciting rush current of transformers, as well as compensate for harmonics successfully. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 25–34, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20397