Lp-加藤クラス測度とソボレフ埋蔵定理の関係について

京都大学新制・課程博士博士(理学)甲第22982号理博第4659号新制||理||1669(附属図書館)京都大学大学院理学研究科数学・数理解析専攻(主査)教授 熊谷 隆, 教授 長谷川 真人, 小澤 登高学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

Spatiotemporal correlations of earthquakes in the continuum limit of the one-dimensional Burridge-Knopoff model

Spatiotemporal correlations of the one-dimensional spring-block (Burridge-Knopoff) model of earthquakes, either with or without the viscosity term, are studied by means of numerical computer simulations. The continuum limit of the model is examined by systematically investigating the model properties with varying the block-size parameter a toward a\to 0. The Kelvin viscosity term is introduced so that the model dynamics possesses a sensible continuum limit. In the presence of the viscosity term, many of the properties of the original discrete BK model are kept qualitatively unchanged even in the continuum limit, although the size of minimum earthquake gets smaller as a gets smaller. One notable exception is the existence/non-existence of the doughnut-like quiescence prior to the mainshock. Although large events of the original discrete BK model accompany seismic acceleration together with a doughnut-like quiescence just before the mainshock, the spatial range of the doughnut-like quiescence becomes narrower as a gets smaller, and in the continuum limit, the doughnut-like quiescence might vanish altogether. The doughnut-like quiescence observed in the discrete BK model is then a phenomenon closely related to the short-length cut-off scale of the model

A case of gastropericardial fistula of a gastric tube after esophagectomy: a case report and review

A 65-year-old man who had received an esophagectomy 10 years earlier was admitted to our hospital for right chest pain. Preoperative examinations showed pneumopericardium, a retrosternal gastric tube, and an active gastric tube ulcer. We diagnosed gastropericardial fistula of the gastric tube ulcer. Emergency surgery included lavage and drainage of the pericardial cavity and plombage of the rectus abdominis muscle flap to the posterior space of the gastric tube. Total parental nutrition and/or enteric nutrition were provided. Due to minor leakage from the ulcer, the patient could start oral intake on the postoperative 49th day, and was discharged from the hospital on the postoperative 86th day after physical rehabilitation. He has been free from complications for more than 33 months after surgery. Here, we review the literature and discuss the etiology and treatment of choice for this rare yet lethal complication in the follow-up after esophagectomy

Nearly homogeneous and isotropic turbulence generated by the interaction of supersonic jets

This study reports the development and characterization of a multiple-supersonic-jet wind tunnel designed to investigate the decay of nearly homogeneous and isotropic turbulence in a compressible regime. The interaction of 36 supersonic jets generates turbulence that decays in the streamwise direction. The velocity field is measured with particle image velocimetry by seeding tracer particles with ethanol condensation. Various velocity statistics are evaluated to diagnose decaying turbulence generated by the supersonic jet interaction. The flow is initially inhomogeneous and anisotropic and possesses intermittent large-scale velocity fluctuations. The flow evolves into a statistically homogeneous and isotropic state as the mean velocity profile becomes uniform. In the nearly homogeneous and isotropic region, the ratio of root-mean-squared velocity fluctuations in the streamwise and vertical directions is about 1.08, the longitudinal integral scales are also similar in these directions, and the large-scale intermittency becomes insignificant. The turbulent kinetic energy per unit mass decays according to a power law with an exponent of about 2, larger than those reported for incompressible grid turbulence. The energy spectra in the inertial subrange agree well with other turbulent flows when normalized by the dissipation rate and kinematic viscosity. The non-dimensional dissipation rate is within a range of 0.51--0.87, which is also consistent with incompressible grid turbulence. These results demonstrate that the multiple-supersonic-jet wind tunnel is helpful in the investigation of decaying homogeneous isotropic turbulence whose generation process is strongly influenced by fluid compressibility