Role of Strain in Controlling the Orientation Distribution in Oscillatory Shear of Diblock Copolymers as Studied by SAXS

Small-angle X-ray scattering is used to examine quantitatively the distribution of lamellar orientation in shear aligned diblocks as a function of strain amplitude at constant shear duration, frequency, and temperature. At all strains, predominantly perpendicular alignment is observed with some parallel alignment. Also, there is a small amount of transverse alignment. This suggests that alignment by shear occurs at the expense of intermediate alignments followed by reducing transverse alignment. Increased strain at constant time increases the sharpness of the distribution of perpendicular alignment.     

Parasite infection and Japanese cedar pollinosis in monkeys

We describe here a specific calcineurin activity in neutrophil lysates, which is dependent on Ca2+, inhibited by trifluoroperazine, and insensitive to okadaic acid. Immunoblotting experiments using a specific antiserum recognized both the A and B chains of calcineurin. Neutrophils treated with cyclosporin A or FK 506 showed a dose-dependent inhibition of calcineurin activity. The effect of oxidant compounds on calcineurin activity was also investigated. Neutrophils treated with hydrogen peroxide (H2O2), where catalase was inhibited with aminotriazole, exhibited a specific inhibition of calcineurin activity. However, the addition of reducing agents to neutrophil extracts partially reversed the inhibition caused by H2O2. A similar inhibitory effect of H2O2 on calcineurin activity was observed to occur in isolated lymphocytes. This is the first demonstration that redox agents modulate calcineurin activity in a cellular system. In addition, electrophoretic mobility shift assays revealed that lipopolysaccharide-induced activation of NF-kappaB in human neutrophils is inhibited by cell pretreatment with H2O2 in a dose-dependent manner. These data indicate that calcineurin activity regulates the functional activity of lipopolysaccharide-induced NF-kappaB/Rel proteins in human neutrophils. These data indicate a role of peroxides in the modulation of calcineurin activity and that the H2O2-dependent NF-kappaB inactivation in neutrophils occurs in concert with inhibition of calcineurin.     

A study of voltage and reactive power control methods for high‐efficiency operation of distribution networks

Transformers with on‐load tap changer and step voltage regulators are most often used for regulating the distribution network voltage. Their use, however, creates certain problems, namely, the voltage control is in discrete steps and the response time is not satisfactory enough. In addition, the power factor (p.f.) compensation relies on capacitors installed by electricity users which creates additional problems manifesting themselves in unexpected overvoltages during light load and increase of power losses. To solve these problems, the authors have proposed a new voltage and p.f. control system for distribution networks based on sophisticated power electronics technology. This paper describes our study on the operating theory of inverter‐controlled regulators and thyristor‐controlled reactors, which play important roles in this system, and the results of simulation through which the usefulness of these equipment has been ascertained. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 76–87, 2000     

Neck electrical impedance for measurement of swallowing

Recently, videofluorography has been used for evaluation of swallowing function in the rehabilitation field. But it is not easy to evaluate swallowing disorders simply. In addition, there are problems of exposure for daily use. We have proposed a measurement method of swallowing using bioelectrical impedance (impedance pharyngography, IPG) which has advantages of easy handling and noninvasive measurement. Appropriate electrode position have been determined. The waveforms of IPG can be obtained with some extent reproducibility. The change of neck electrical impedance in the pharyngeal phase is mainly caused by the changes of equivalent cross sectional area near the epiglottis. The possibilities of applications for clinical diagnosis have been shown. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 35–44, 2000     

XYΘ actuators using piezoelectric and electromagnetic actuators

Microactuators with multiple degrees of freedom, which can provide many benefits in precision engineering, are in demand for industrial applications. We propose two new actuators (Y‐type and Δ‐type) which can move in the x, y, and θ directions. They are combinations of piezoelectric and electromagnetic actuators. The proposed actuators realize high resolution via the piezoelectric actuators. We describe the structure and principle of the proposed actuators, and discuss their feasibility. A resolution of 70 nm in the x direction and of 0.5 μrad in the θ direction was obtained with the Y‐type actuator. A resolution of 90 nm in the x direction and of 0.6 μrad in the θ direction was obtained with the Δ‐type actuator. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 44–51, 2000     

Electron-Spin-Based Phenomena Arising from Pore Edges of Graphene Nanomeshes

Unique atomic structures at the edges of graphenes yield a variety of interesting phenomena. In spite of carbon-based material with only sp ² bonds, the zigzag-type atomic structure of graphene edges theoretically produces spontaneous spin polarization of electrons due to mutual Coulomb interaction of extremely high electron density of states localizing at the flat energy band. However, spin-based phenomena have been experimentally observed only in defect-related carbon systems. Here, we fabricate honeycomb-like arrays of low-defect hexagonal nanopores (graphene nanomeshes; GNMs) on graphenes, which produce a large amount of pore edges, by using a nonlithographic method (nanoporous alumina templates). We find large-magnitude ferromagnetism arising from polarized electron spins localizing at the zigzag-nanopore edges of monolayer GNMs. Moreover, spin pumping effect depending on GNM structures is found for magnetic fields applied in parallel with the few-layer GNM planes. These promise to be a realization of rare-element free magnets and also novel all-carbon spintronic devices.     

Wireless communications in the twenty-first century: a perspective

Wireless communications are expected to be the dominant mode of access technology in the next century. Besides voice, a new range of services such as multimedia, high-speed data, etc. are being offered for delivery over wireless networks. Mobility will be seamless, realizing the concept of persons being in contact anywhere, at any time. Two developments are likely to have a substantial impact on the mobile communications systems deployed in the twenty-first century: the adoption of International Mobile Telecommunications-2000 and wireless asynchronous transfer mode (ATM). They are two different but cooperative approaches to providing high-speed wireless access. The limitations of the radio-frequency spectrum and radio channel propagation impose special constraints on the technologies of systems to be deployed. To make future mobile systems globally acceptable, standardization efforts are underway in the International Telecommunications Union and the ATM Forum. This paper reviews the international standardization efforts, the challenges to the technologies imposed by the radio spectrum limitations, radio channel propagation-induced distortions, and possible solutions. Evolution, migration, and architecture issues also are discussed     

Si-analog IC's for 20 Gb/s optical receiver

Two Si-Analog IC's, a preamplifier IC and a decision IC, for a 20 Gb/s optical receiver have been developed using SiGe-base bipolar transistors having a 60 GHz maximum cutoff frequency. The preamplifier employing a dual feedback loop increases the -3 dB bandwidth up to 19 GHz. A decision IC, composed of a gain controllable amplifier with a bias stabilization circuit and D-F/F, operated at up to 20 Gb/s with a 200-mVp-p input sensitivity     

Heat removal characteristics of vault storage system with cross flow for spent fuel

Since the amount of spent fuel to be stored is expected to steadily increase in Japan, a use of large-scale dry storage facilities is considered to be a promising method in practice at reasonable economic cost. The present study is concerned with the heat removal experiment of vault storage system adopting cross flow with passive cooling, using a 1/5 scale model. The results show that the flow pattern of air in the storage module strongly depends on the ratio of the buoyancy to the inertia force. A simple method to estimate air flow patterns in the storage module was proposed, where the Ri (Richardson) number was considered as the most representative parameter. Then the heat transfer rate from a storage tube to cooling air was estimated, which could apply to the design of a full-scale vault storage system with cross flow, in which dozens of storage tubes were placed. The acquired information was also used to optimize heat removal design of the vault storage system in the present study.     

Photochemical Acceleration of DNA Strand Displacement by Using Ultrafast DNA Photo-crosslinking

DNA strand displacement is an essential reaction in genetic recombination, biological processes, and DNA nanotechnology. In particular, various DNA nanodevices enable complicated calculations. However, it takes time before the output is obtained, so acceleration of DNA strand displacement is required for a rapid-response DNA nanodevice. Herein, DNA strand displacement by using DNA photo-crosslinking to accelerate this displacement is evaluated. The DNA photo-crosslinking of 3-cyanovinylcarbazole (^CNVK) was accelerated at least 20 times, showing a faster DNA strand displacement. The rate of photo-crosslinking is a key factor and the rate of DNA strand displacement is accelerated through ultrafast photo-crosslinking. The rate of DNA strand displacement was regulated by photoirradiation energy.