Taku Goto 교수

We have developed a thermally conductive flexible elastomer as a composite material with slide-ring (SR) materials and boron nitride (BN) particles surface-modified via plasma in solution. This composite shows excellent properties as a flexible insulator for thermal management. Surface modification of BN particles using plasma in solution increases the tensile strength, extension ratio at break, toughness, and rubber characteristics of the composites, compared to SR and non-modified BN, while th

The effect of liquid medium and its pressure on the photoluminescence of ZnO nanoparticles prepared via laser ablation of Zn targets in various water–ethanol mixtures is studied. As the ethanol content increases, the photoluminescence of the product changes, while metallic zinc is observed to emerge in nanomaterials prepared in ethanol-rich environments. The applied pressure had a less profound effect, mainly affecting materials produced in water or water–ethanol, and much less those generated i

To make preparation for constructing the symmetric vertex function in the string model of hadrons, we study the symmetric vertex in the bi-local field model of hadrons. It is shown that the vertex operator is obtained by following the quark line picture and employing the vertex operator we can obtain the amplitude for the scattering of two bi-local fields. Unfortunately the asymptotic behaviour behaviour of the scattering amplitude obtained here is not good enough as a whole.

According to this theory, physical states are represented by continuous linear functionals on a space of good functions which are everywhere differentiable any number of times and decrease

Following homogeneous canonical formalism where the time is treated on an equal footing with the space coordinates, we propose an alternative formulation of quantum mechanics in which the time is considered as a dynamical variable. The basic equation corresponding to and being equivalent to the ordinary Schrödinger equation is obtained when we consider the space coordinates x as a parameter corresponding to the time t in the ordinary formulation. The formal solution of this equation is given and

We have developed a thermally conductive flexible elastomer as a composite materials with slide-ring (SR) materials and boron nitride (BN) particles surface-modified via plasma in solution. This seems to be a promising materials as a flexible insulator for thermal management. Fourier transform infrared spectrum, Raman spectrum, and X-ray diffraction patterns of BN particles indicate that plasma-surface modification introduces OH functional groups on surface of BN particles. Furthermore, X-ray co

Conductance of photoexcited ZnO nanoparticles with various defects has been investigated in oxygen. ZnO nanoparticles, which show strong photoluminescence peaks originating from interstitial zinc atom (Zni) and singly charged oxygen vacancy (VO+), show oxygen-pressure-dependent conductance changes caused by photoexcitation. Herein, a model is proposed to simulate the conductance changes.

A formal solution of the Fokker-Planck equation with the constant diffusion coefficient is obtained in the operator approach proposed previously.1) The result is the same as those obtained recently by several authors in the path integral representation. The results obtained in this paper are easily generalized to the multi-dimensional case.

Abstract Hexagonal boron nitride (h-BN) sheets have numerous applications, but current low-cost, environmentally friendly techniques for h-BN exfoliation yield undesirably small sheet sizes. We have developed a novel chemical-free method to prepare large h-BN nanosheets (BNNSs) by the exfoliation of h-BN using plasma with cavitation bubbles in water, named here as cavitation-bubble plasma. Unlike ordinary liquid exfoliation methods, which reduce the sheet size of BNNSs compared with that of the

The relativistic mechanics of a system composed of two points interacting with each other by an action at a distance is investigated. It is explicitly taken into account that these two points are on a space-like hyperplane at equal τ (the ordering parameter). In the canonical theory, we have several constraints which are consistent with each other. Considering one of them as a strong relation, we obtain a relativistic wave equation with the supplementary conditions corresponding correctly to the

The canonical formalism of the electromagnetic field in the Landau gauge is studied. Unlike the case of Nakanishi, the dipole ghost states are not introduced. The singular character of the longitudinal and scalar components are pointed out, and the difficulty originated from the unnormalizable norm of the state vectors are evaded by an appropriate limiting procedure. The interacting case is also discussed in the interaction representation.