- 著者
- Muhammad KOZIN Keisuke KUSAKABE Masatoshi ARAMAKI Naoya YAMADA Satoshi OUE Yukiko OZAKI Osamu FURUKIMI Masaki TANAKA
- 出版者
- Japan Society of Powder and Powder Metallurgy
- 雑誌
- 粉体および粉末冶金 (ISSN:05328799)
- 巻号頁・発行日
- vol.67, no.4, pp.173-181, 2020-04-15 (Released:2020-04-15)
- 参考文献数
- 24
- 被引用文献数
- 1
In the present study, we have examined the wear properties of the sintered pure iron subjected to two distinct heat treatments such as nitriding-quenching (NQ) and carburizing-quenching (CQ). Based on our current observations, the martensite layer was formed on the surface layer following each treatment, whereas the hardness of the NQ martensite was much higher than that of the CQ one. The wear of the CQ specimen was slightly smaller than that of the NQ martensite, despite the lower value of the initial hardness. Meanwhile, the hardness of the CQ surface after the sliding tests significantly elevated relative to the NQ surface resulting in the better wear resistance. EBSD analysis demonstrated that the plastic deformation on the CQ surface along the sliding direction. Furthermore, the micro area X-ray diffraction along the surface layer of the CQ surface showed that a small amount of the retained austeite which reduced locally during the test. Therefore, the CQ-treated surface showed the excellent wear resistivity due to the surface hardening by the stress-induced transformation of the retained austenite dispersed in the martensite, in addition to the strain hardening of the martensite itself. In contrast, the worn surface of the NQ specimen showed slight plastic deformations of the ferrite grains beneath the martensite layer, but not in the surface martensite layer. This deformation under the martensite layer was due to the hardness gap between inward and the heat-treated surface, and might contribute to form the concave profile on the sliding surface. Consequently, this study could demonstrate such the difference in the wear mechanisms between the CQ and the NQ specimens.
- 著者
- Atsushi Yanagisawa Yuhei Kinehara Masaki Tanaka Ryusuke Ninomiya Miho Nishioka Susumu Ochiai Ryu Jokoji Shoichi Ihara Kunihiko Hashimoto Isao Tachibana
- 出版者
- The Japanese Society of Internal Medicine
- 雑誌
- Internal Medicine (ISSN:09182918)
- 巻号頁・発行日
- pp.1520-22, (Released:2023-05-10)
- 参考文献数
- 25
A 39-year-old vegan man was admitted with diabetic ketoacidosis. He had also developed pneumonia that was unresponsive to antibiotics. Based on bronchoscopy findings, the diagnosis of Candida pneumonia was made, and the pulmonary shadow disappeared rapidly after antifungal therapy. Candida pneumonia has been mostly reported in severely immunocompromised patients. This is a rare case of Candida pneumonia that was found in a young vegan man with diabetes mellitus (DM). Although malnutrition caused by DM or an unbalanced diet is often underestimated as a cause of immunodeficiency, these conditions can be risk factors for serious opportunistic infections, including Candida pneumonia.