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Preparation of Intermetallic Compound of Ternary Al-B-C System by Mechanical Alloying
Takahashi Teruo,Yamashita Michiru,Yamada Kazutoshi,Kohzuki Hidenori 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
Metallic compound of ternary Al-B-C system was prepared by mechanical alloying (MA) using Al, boron and graphite powders as starting materials. MA was carried out using Spex 8000 mixer/mill for 50 hours in an argon atmosphere without process control reagent such as methyl alcohol. The MA powders obtained were heat-treated in vacuum at the temperature of 873 and 1273 K for 5 hour. Pure ternary Al-B-C compound was obtained in the chemical content of Al:B:C=55:27:18. The ternary compound obtained in this study has a new phase whose crystal structure is not identified yet.
Ryo Kanematsu,Masaki Mizuno,Tomoo Inoue,Toshiyuki Takahashi,Toshiki Endo,Seiji Shigekawa,Jun Muto,Daisuke Umebayashi,Takafumi Mitsuhara,Kazutoshi Hida,Junya Hanakita 대한척추신경외과학회 2023 Neurospine Vol.20 No.3
Objective: The impact of adjuvant radiotherapy on overall survival (OS) and progressionfree survival (PFS) of patients with grade II spinal cord astrocytomas remains controversial. Additionally, the relationship between progression and clinical deterioration after radiotherapy has not been well investigated. Methods: This study included 53 patients with grade II intramedullary spinal cord astrocytomas treated by either subtotal, partial resection or open biopsy. Their clinical performance status was assessed immediately before operation and 1, 6, 12, 24, and 60 months after surgery by Karnofsky Performance Scale (KPS). Patients with and without adjuvant radiotherapy were compared. Results: The groups with and without radiation comprised 23 and 30 patients with a mean age of 50.3 ± 22.6 years (range, 2–88 years). The mean overall disease progression rate was 47.1% during a mean follow-up period of 48.4 ± 39.8 months (range, 2.5–144.5 months). In the radiation group, 11 patients (47.8%) presented with progressive disease, whereas 14 patients (46.7%) presented with progressive disease in the group without radiation. There were no significant differences in OS or PFS among patients with or without adjuvant radiotherapy. KPS in both groups, especially radiation group, gradually decreased after operation and deteriorated before the confirmation of disease progression. Conclusion: Adjuvant radiotherapy did not show effectiveness regarding PFS or OS in patients with grade II spinal cord astrocytoma according to classical classification based on pathohistological findings.
Yun, Jungheum,Chung, Hee-Suk,Lee, Sang-Geul,Bae, Jong-Seong,Hong, Tae Eun,Takahashi, Kazutoshi,Yu, Seung Min,Park, Jucheol,Guo, Qixin,Lee, Gun-Hwan,Han, Seung Zeon,Ikoma, Yoshifumi,Choi, Eun-Ae The Royal Society of Chemistry 2020 Nanoscale Vol.12 No.3
<P>Artificially designing the crystal orientation and facets of noble metal nanoparticles is important to realize unique chemical and physical features that are very different from those of noble metals in bulk geometries. However, relative to their counterparts synthesized in wet-chemical processes, vapor-depositing noble metal nanoparticles with the desired crystallographic features while avoiding any notable impurities is quite challenging because this task requires breaking away from the thermodynamically favorable geometry of nanoparticles. We used plasma-generated N atoms as a surface-active agent, a so-called surfactant, to control the structural development of Ag nanoparticles supported on a chemically heterogeneous ZnO substrate. The N-surfactant-facilitated sputter deposition provided strong selectivity for crystalline orientation and facets, leading to a highly flattened nanoparticle shape that clearly deviated from the energetically favorable spherical polyhedra, due to the drastic decreases in the surface free energies of Ag nanoparticles in the presence of the N surfactant. The Ag nanoparticles successively developed a nearly unidirectional (111) orientation aligned by stimulating the crystalline coupling of Ag along the orientation of the ZnO substrate. The experimental and simulation results not only offer new insights into the advantages of N as a surfactant for the orientation and shape-controlled synthesis of Ag nanoparticles <I>via</I> sputter deposition but also provide the first solid evidence validating that immiscible, nonresidual gaseous surfactants can be used in the vapor deposition processes of noble metal nanoparticles to manipulate their surface free energies.</P>