Effect of dimension ratio on the magnetic properties of tape-wound toroidal core with ac excitation

Tape-wound toroidal cores are used widely as magnetic devices of electronic equipment and instruments. In the design of equipment employing magnetic cores, it is necessary to know the relation between the magnetic properties of the core and the magnetic properties of the material. This paper describes the effect of the dimension ratio of the core on the magnetic properties for the sinusoidal flux waveform drive condition. In carrying out the analysis, a mode analysis in which the magnetization characteristics are approximated by a piecewise-linear curve is adopted. From the results obtained by the numerical analysis, local flux waveforms and exciting current waveforms of the core are shown. As a result, the relation between iron loss and magnetizing apparent power of the core and the dimension ratio is derived. These results were confirmed by experiments.     

Development of high-efficiency a-Si solar cell submodule with a size of 30 cm × 40 cm

We have achieved a stabilized conversion efficiency of 8.9% in a single-junction a-Si solar cell and 10.6% in a double-junction a-Si/a-SiGe solar cell for a size of 1 cm², which are the world's highest values achieved so far for this size and structure. We have been investigating the improvement of stability in a-SiGe film with regard to the bottom cell i-layer, and the control of E_opt in a-SiGe film in order to confirm the tandem cell design. On the other hand, uniformity of ± 1% has been obtained in conversion efficiency for many small cells fabricated in a size of 30 cm × 40 cm, evaluated by using a-Si single-junction structure. As a result, we have achieved the stabilized high-effective area conversion efficiency of 8.64% in a 30 cm × 40 cm a-Si/a-Si tandem submodule. The combination of the above techniques and further optimization can be expected to achieve a stabilized conversion efficiency of more than 10% for a 30 cm × 40 cm double-junction a-Si/a-SiGe submodule.     

Activity coefficient of oxygen in copper-tellurium melts

Activity coefficient of oxygen, γ_o, in copper-tellurium melts was determined at 1423 K utilizing a modified coulometric titration technique with the following electrochemical cell: O in Cu-Te melts/ZrO₂(+CaO)/air, Pt. The γ_o values in the vicinity ofN _Te = 0.30 are much smaller than those in the tellurium-dilute copper-tellurium melts, and increase rapidly with the tellurium composition. The shape of the In γ_o vs solvent composition curve is quite similar to that in Cu-S and Tl-Te melts. This type of compositional dependence can be successfully described by a proposed solution model. Formerly Graduate Student, Osaka University     

Role of ferrite and austenite phases on the deformation behavior and mechanical properties in heterogeneous nanostructured duplex stainless steel aged at different temperatures

Journal of Materials Science - The effects of aging on the mechanical properties of a heavily cold-rolled ferrite–austenite duplex stainless steel were systematically investigated. The...     

Sensory regulation of stance-to-swing transition in generation of adaptive human walking: A simulation study

In this paper, we investigated sensory mechanisms to regulate the transition from the stance to swing phases in the generation of adaptive human bipedal walking based on a neuromusculoskeletal model. We examined the contributions of the sensory information from the force-sensitive afferents in the ankle extensor muscle and from the position-sensitive afferents from the hip, inspired by a neuro-mechanical simulation for the stepping of the hind legs of cats. Our simulation results showed that the sensory signals related to the force in the ankle extensor muscle make a larger contribution than sensory signals related to the joint angle at the hip to produce robust walking against disturbances, as observed in the simulation results of cat locomotion. This suggests that such a sensorimotor mechanism is a general property and is also embedded in the neuro-control system of human bipedal walking.     

The treatment of complex English nominalizations in machine translation

This paper concerns the treatment, in the context of machine translation, of English complex nominal groups which can be considered as nominalizations of verb phrases. We discuss the fact that many styles of English prose which are suitable for translation by machine typically favor the use of nominal rather than verbal syntagms. But such constructions when translated literally are often considered unnatural. The general problem is described in detail, with examples. The more specific problem of recognizing nominalizations and analyzing their structure is considered. How and where to achieve the required syntactic transformation is discussed, and exemplified.On leave of absence from the Centre for Computational Linguistics, University of Manchester Institute of Science and Technology, England.     

Adaptive behavior in turning of an oscillator-driven biped robot

This paper concentrates on a biped robot’s turning behavior that consists of straight and curved walking and the transition between these two patterns. We investigate how a robot achieves adaptive walking during such turning by focusing on rhythm control and propose a locomotion control system that generates robot motions by rhythmic signals from internal oscillators and modulates signal generation based on touch sensor signals. First, we verify that the robot attains limit cycles of straight and curved walking by numerical simulations and hardware experiments. Second, we examine the transition between these walking patterns based on the basin of attraction of the limit cycles in numerical simulations. Finally, we verify whether the robot actually accomplishes transition and turning by hardware experiments. This paper clarifies that the robot establishes such turning motions by adequate modulation of walking rhythm and phase through interactions between the dynamics of its mechanical system, oscillators, and environment.

Interaction of newly defined stress intensity factors for angular corners in a row of diamond-shaped inclusions

This paper deals with a row of equally spaced equal diamond-shaped inclusions with angular corners under various loading conditions. The problem is formulated as a system of singular integral equations with Cauchy-type singularities, where the unknown functions are the densities of body forces distributed in infinite plates having the same elastic constants of the matrix and inclusions. In order to analyze the problems accurately, the unknown functions of the body force densities are expressed as a linear combination of two types of fundamental density functions and power series, where the fundamental density functions are chosen to represent the symmetric stress singularity of $1/r^{1 - \lambda _1 } $ and the skew-symmetric stress singularity of $1/r^{1 - \lambda _2 } $ . Then, newly defined stress intensity factors for angular corners are systematically calculated for various shapes, spacings, elastic constants and numbers of the diamond-shaped inclusions in a plate subjected to uniaxial tension, biaxial tension and in-plane shear. For all types of diamond-shaped inclusions, the stress intensity factor is shown to be linearly related to the reciprocal of the number of diamond-shaped inclusions.     

Manufacturing Silicon Carbide Microrotors by Reactive Hot Isostatic Pressing within Micromachined Silicon Molds

A novel ceramic microfabrication process—based on the idea of silicon carbide (SiC) reaction sintering within a micromachined silicon mold—has been developed to produce a SiC microroter for miniaturized gas turbines. The new process involves the micromachining of silicon molds; filling the molds with powder mixtures of α-SiC, graphite, and phenol resin; bonding the molds with an adhesive; reaction sintering by hot isostatic pressing (HIP); and the releasing of a reaction-sintered workpiece from the mold by wet etching. Using this process, we have successfully fabricated SiC microrotors with a diameter of 5 mm, whose complicated geometry was well transferred from the negative shape of the micromachined silicon mold. The reaction-HIPed SiC ceramics within Si molds showed reasonably good mechanical properties, which are comparable to those of the commercialized reaction-sintered SiC ceramics.