717 publications from this institution
The emergence of power semiconductor devices such as insulated-gate bipolar transistors (IGBTs) or injection-enhanced gate transistors (IEGTs) and gate-commutated turn-off (GCT) thyristors or integrated gate-commutated thyristors (IGCTs) enables power conversion systems to expand into utility and industry applications. Much attention has been paid to power switching devices based on wide-bandgap semiconductors such as silicon carbide(SiC). These devices are expected to have the following advantages over silicon devices; low switching and conduction losses, especially in power conversion systems operating as high as, or exceeding 600 V. This paper describes trends in power electronics and motor drives, including the personal views and expectations of the author.
Primary leiomyosarcoma of the pharynx is extremely rare. A review of the literature revealed only 7 cases of pharyngeal leiomyosarcoma in Japan. We describe the case of a 72-year-old man with a leiomyosarcoma of the middle pharynx in this paper. Seven years ago, the patient had a malignant melanoma of the pharynx, and total extirpation of the tumor was performed with reconstruction of the pharynx using a pectoralis major myocutaneous flap, irradiation (20 Gy), and chemotherapy. In this case, leiomyosarcoma arising from the pharynx occurred in the irradiation field. Only 12 cases of radiation-induced leiomyosarcoma have been reported in the Japanese and foreign literature.
