Nagoya University · Medicine
Professor Kenji Imai's research lab specializes in nonlinear mathematical physics and soliton theory, with a focus on integrable systems, exact solutions of nonlinear partial differential equations, and advanced transformation methods such as the Darboux and binary Darboux transformations. The lab investigates localized solutions—such as dromions, lumps, and vortex-antivortex structures—in (2+1)-dimensional integrable equations like the Ishimori and Kaup-Newell equations, aiming to uncover new analytical solutions and their dynamical properties. Additionally, the lab contributes to applied mathematical physics through the development of novel spectroscopic techniques, such as room-temperature piezoelectric photothermal spectroscopy, for probing quantum well structures in semiconductor materials. The research bridges theoretical mathematical physics with experimental applications in condensed matter and materials science.
Figures are computed from collected data and may differ slightly.
It is known that the Ishimori-I equation, which is the (2+1)-dimensional generalization of the classical continuous Heisenberg ferromagnet equation, has various localized solutions such as the dromion, lump and rationally-exponentially localized solutions. In this paper localized solutions of the Ishimori-I equation are constructed explicitly in terms of grammian determinants by using the binary Darboux transformation, and it is shown that they include not only the multi-soliton (dromion, lump a
In this paper the Kaup-Newell (KN) inverse scattering formulation are generalized, and a new Darboux transformation is introduced for it. Some Darboux covariant (1+1) dimensional soliton equations associated with the generalized KN formulation are derived systematically, which include not only the derivative nonlinear Schrödinger (DNLS), the modified KdV, the sine-Gordon and the massive Thirring equations but also some new nonlinear time evolution equations. Multi-soliton solutions of the DNLS e
SI is a better parameter for PPH detection in vaginal deliveries than other vital signs. However, clinical judgment must incorporate other vital signs and symptoms associated with hypovolemic shock due to the low sensitivity of SI.
It is known that the IshimoriII equation has the lump solutions decaying polynomially in all directions, which are called the multi-vortex (and multi-antivortex) solutions; they are constructed by Hirota's method and a-dressing method. In this paper we construct rational solutions of the Ishimori-II equation by means of the Darboux transformation and show that they contain not only the multivortex solutions obtained by Hirota's method as a special case, but also new lump solutions, such as mixed
The aim of the present study was to investigate long-term outcomes of the offspring in a lipopolysaccharide (LPS)-induced maternal immune activation (MIA) model and the effect of maternal molecular hydrogen (H<sub>2</sub>) administration. We have previously demonstrated in the MIA mouse model that maternal administration of H<sub>2</sub> attenuates oxidative damage and neuroinflammation, including induced pro-inflammatory cytokines and microglial activation, in the fetal brain. Short-term memory
Room-temperature piezoelectric photothermal spectroscopy (PPTS) measurements were carried out for the single-quantum-well (SQW) structures of GaInNAs. Four as-grown samples with thicknesses of 10, 7, 5 and 3 nm were used to investigate the quantum confinement effect in the SQW. The exciton contribution was clearly distinguished from the two-dimensional step like band-to-band transition. The thickness dependence of PPT signal peak energy were well understood by quantum mechanics. The decrease in
The present study assessed whether lipid peroxidation in plasma might predict restenosis after coronary balloon angioplasty. A total of 87 patients, who had undergone successful coronary balloon angioplasty using standard techniques, were enrolled. Fasting blood samples before the intervention were measured for plasma levels of thiobarbituric acid reactive substances (TBARS, an indicator of lipid peroxidation). Angiography was carried out before and 15 min after angioplasty, and at follow-up (4
<i>Background and Objectives:</i> The effects of postpartum zinc supplementation are still unclear. Our purpose in this study is to investigate the association between Zn supplementation and postpartum depression, defined by an Edinburgh Postnatal Depression Scale (EPDS) score ≥ 9, and the effect on the hematological status of postpartum women. <i>Materials and Methods:</i> We first investigated whether zinc supplementation affected the perioperative levels of zinc, hemoglobin, and hematocrit in
We present an n-dimensional integrable homogeneous Lotka--Volterra system, which has $(n^2-1)$-dimensional Lie symmetry algebra. Moreover a wider integrable family is derived from the structure of the Lie algebra.
Our findings suggest that the PROPESS efficacy depends on Bishop score at insertion and that vaginal bleeding at PROPESS insertion might have a significantly positive effect on cervical ripening in term pregnant women.
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