A Fuzzy-Fuzzy Relation and its Application to the Clustering Technique

Behaviormetrika - In this paper we have formulated a fuzzy-fuzzy relation which is an extension of the fuzzy one, and have investigated its properties. Using some characteristic property which...     

Graphitization and sintering of coals under pressure

Anthracite from Abernant, Wales, and sub-bituminous coal from Taiheiyo, Hokkaido, were graphitized above 1500 °C at a pressure of 0.5 MPa. The graphitization occurred abruptly in a very narrow range of temperature. In association with the graphitization, sintering of the sample powder and densification were observed.     

A High Performance AC Servo System with Permanent Magnet Synchronous Motors

A high performance ac servo system with permanent magnet synchronous motor, including a field-weakening control and a high-speed current response control of PWM inverter is proposed. For the field weakening, the d-axis armature current is adequately controlled through a microprocessor. The novel current control scheme of PWM inverter includes the motor neutral point potential stabilization and the switching carrier frequency equalization.     

Hydrothermal synthesis and properties of Na0.70MnO2.25 layer crystal

The single crystals of Na_0.70MnO_2.25 were hydrothermally synthesized by the reaction of MnO₂ with hydrothermal NaOH solution. The crystal of Na_0.70MnO_2.25 has the layer structure in which sodium ions are located between the sheets composed by MnO₆ octahedra. The oxygen fugacity under hydrothermal conditions was found to influence the valence of manganese ion in a grown crystal, determining the kind of crystalline phase in the NaMnO system. The chemical and physical properties of Na_0.70MnO_2.25 were measured.     

High-Beta Steady-State FRC Plasma Sustained by Rotating Magnetic Field with Spatial High-Harmonic Components

Field-reversed configurations (FRCs) driven by rotating magnetic fields (RMFs) with spatial high-harmonic components have been studied in the metal flux conserver of the FRC injection experiment (FIX). The high-harmonic RMF method has some unique features; (1) field lines of the RMF do not penetrate or cross the vessel wall, (2) selective penetration/exclusion of the fundamental/high-harmonic RMF component will result in a generation of effective magnetic pressure near the separatrix, which helps to keep the separatrix away from the vessel wall, (3) strong azimuthal non-uniformity of the RMF will cause the n = 4 deformation of the core FRC plasma, which will eliminate the destructive modes caused by the rotation of the plasma column. The RMF method with high harmonics will provide quasi-steady current drive of high-beta FRC plasmas without destructive n = 2 rotational mode and will be helpful in reducing the particle loss and thermal load when applied to the fusion core plasma.     

The role of alloying elements in improving the corrosion resistance of amorphous iron base alloys

X-ray photo-electron spectroscopy has been used to investigate the correlation between the compositions of a surface film and the underlying alloy and the beneficial effects of alloying elements. The addition of alloying elements less noble than iron increases the corrosion resistance in the active region by improving the protective quality of the corrosion product film in which the cations of alloying elements are significantly concentrated. Even if the passivity of alloying elements is not stable in the passive region of alloys, the alloying asists the formation of passive hydrated iron oxy-hydroxide film by decreasing the dissolution rate of alloys prior to the passive film formation. The improvement of corrosion resistance by alloying with the elements more noble than iron has been interpreted in terms of the decrease in the anodic activity of alloys.     

The role of alloying elements in improving the corrosion resistance of amorphous iron base alloys

X-ray photo-electron spectroscopy has been used to investigate the correlation between the compositions of a surface film and the underlying alloy and the beneficial effects of alloying elements. The addition of alloying elements less noble than iron increases the corrosion resistance in the active region by improving the protective quality of the corrosion product film in which the cations of alloying elements are significantly concentrated. Even if the passivity of alloying elements is not stable in the passive region of alloys, the alloying asists the formation of passive hydrated iron oxy-hydroxide film by decreasing the dissolution rate of alloys prior to the passive film formation. The improvement of corrosion resistance by alloying with the elements more noble than iron has been interpreted in terms of the decrease in the anodic activity of alloys.