The University of Tokyo · Materials Science
Professor Hatsumi Mori's research lab specializes in the synthesis, structural characterization, and electronic property analysis of organic conductors and superconductors, with a focus on BEDT-TTF-based salts. The lab investigates phase transitions, metal-insulator transitions, and superconductivity in these materials, particularly in θ-type and κ-type structures, using techniques such as X-ray crystallography, band structure calculations, and electrical transport measurements. The group also explores applications in power system analysis, including contingency screening and state estimation using advanced mathematical methods like the Tchebychev iteration and graph theory-based topological observability. Their work bridges fundamental materials science with practical engineering applications in energy and power systems.
Figures are computed from collected data and may differ slightly.
The behavior of the phase transitions is mapped out as a function of the dihedral angle (\ensuremath{\theta}) or the transfer integral $(t)$ between donor columns for \ensuremath{\theta}-type BEDT-TTF [BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene, abbreviated as ET] salts involving the series $\ensuremath{\theta}\ensuremath{-}(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F}{)}_{2}{\mathrm{MM}}^{\ensuremath{'}}(\mathrm{SCN}{)}_{4}$ [$M=\mathrm{T}\mathrm{l},
Abstract The crystal structures of (BEDT–TTF)2[MHg(SCN)4] (M=K at 298 and 104 K and M=NH4 at 298 K) were determined by X-ray analyses. A donor layer and an anion sheet stack alternately along the b-axis. The packing pattern of the donor is close to α-phase, while an anion sheet constructs a thick two-dimensional polymer plane parallel to (010). The linkage of (Remark: Graphics omitted.) (or NH4) (Remark: Graphics omitted.) in an anion sheet is very unique. The band structure calculation indicate
This paper proposes an efficient method for contingency screening in power systems. Contingency analysis requires substantial amounts of computational time in evaluating data for controlling generating units or power flows. In this paper, the Tchebychev iteration method of an indirect method is presented for solving a set of linear equations of fast decoupled power flow (FDPF) in the contingency screening. Furthermore, the precondition technique is introduced to improve the convergence character
Since the first discovery of an organic superconductor, TMTSF 2 PF 6 (TMTSF = tetramethyltetraselenafulvalene) with the superconducting transition temperature ( T c )=0.9 K under 12 kbar, by the suppression of spin density wave (SDW) state, approximately 120 organic superconductors have been found. Among them, the highest T c is 14.2 K under 82 kbar for β'-(BEDT-TTF) 2 ICl 2 [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene]. Organic superconductors are categorized into three groups. (1) A super
Abstract Crystal structure analyses, band calculations, and electrical resistivity and magnetic susceptibility measurements have been carried out for new θ-type BEDT-TTF [bis(ethylenedithio)tetrathiafulvalene; abbreviated as ET] salts, θ-(BEDT-TTF)2TlCo(SCN)4 and θ-(BEDT-TTF)2TlZn(SCN)4 [abbreviated as θ-TlCo and θ-TlZn], as well as crystal structure analyses of θ-(BEDT-TTF)2RbM′(SCN)4 [M′ = Co, Zn; abbreviated as θ-RbM′]. θ-TlCo and θ-RbM′ [M′ = Co, Zn] are isostructural to the previously repor
A new unified method is presented for dealing with the problems of topological observability in power system state estimation: identification of network topological observability, and branches or nodes where pseudo-measurements are necessary to recover the whole network topological observability. The method is based on evaluating the minimum spanning tree in graph theory. The proposed method has been successfully applied to several sample systems and its applicability to real-sized power systems
Broken line transformations consist of three elementary processes; the staircase processes, the rotation around a fixed point and the hopping between different branches. Their relative weights determine the main feature of the time-correlation function <xn || x0> of mapping xn = f(xn−1), (n = 1, 2, ⋯). It is shown that , where is a linear operator closely related to the Frobenius-Perron operator. Eigenvalues and eigenfunctions of determine the time-correlation function. By means of this method t
Abstract New three-component organic conductors, (BEDT-TTF)2MM′(SCN)4 [M = K, Rb, Cs; M′ = Co, Zn, Cd], are prepared. The crystal structure analyses of α-ET2CsCo(SCN)4, ETZn(SCN)3, α-ET2RbZn(SCN)4, α-ET2CsZn(SCN)4, α-ETCd0.66(SCN)2, and ET2CsCd(SCN)4 are carried out. Most of salts have the α-type donor arrangement and the polymer sheet like [···M′2+···(SCN)−···M+···] in a thick anion layer. Especially α-(BEDT-TTF)2CsM′(SCN)4 [M′ = Co and Zn] are metallic down to 20 K.
This paper presents a clustering method for preprocessing input data of short-term load forecasting in power systems. Clustering the input data prior to forecasting with the artificial neural network(ANN) decreases the prediction errors observed. In this paper, an MLP ANN is used to deal with one-step-ahead daily maximum load forecasting, and the deterministic annealing (DA) clustering is employed to classify input data into clusters. The DA clustering is based on the principle of maximum entrop
The fractal dimensions of chaotic flows are shown to be given D=m0+m+{1+|λ+/λ-|}, where m0 and m+ are the numbers of zero and positive Lyapunov characteristic exponents λα and λ± are the mean values of positive and negative λα respectively.
Organic acid–base salts have attracted increasing attention as a promising candidate of anhydrous proton conductors. In this study, we have successfully disclosed the relationship between proton conductivity and hydrogen-bond (H-bond) interactions in such kinds of organic salts, composed of dicarboxylic acid and imidazole. We have grown high-quality single crystals of imidazolium succinate (Im-Suc) or glutarate (Im-Glu) with two-dimensional H-bonding networks and measured the proton conductivity
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