- 著者
- 余語 利信 松雄 茂 中 重治
- 出版者
- 公益社団法人日本セラミックス協会
- 雑誌
- 窯業協會誌 (ISSN:18842127)
- 巻号頁・発行日
- vol.95, no.1097, pp.94-98, 1987-01-01
- 被引用文献数
- 8
Highly pure boron nitride of low crystallinity could be synthesized from triammoniadecaborane and ammonia below 800°C under atmospheric pressure. Triammoniadecaborane reacted with ammonia at temperatures between 300° and 450°C, and formed an amorphous solid containing BN, NH and BH bonds. According to the data of IR spectrum, the BH absorption band at 2500cm<sup>-1</sup> decreased in intensity with increasing temperature, and disappeared at 800°C. The 800cm<sup>-1</sup> band assigned to the BNB bonding increased in intensity from 700° to 800°C. The degree of alignment of the B<sub>3</sub>N<sub>3</sub> hexagonal layer increased as the reaction time increased from 2h to 10h at 800°C. The X-ray diffraction profiles of the product formed at 800°C for 10h showed the broad diffractions centered at 2θ=25.5° and 42.0° (Cu Kα). The crystallization of boron nitride synthesized at 800°C for 10h proceeded above 1180°C. The 100 reflection of hexagonal boron nitride was separated from the broad 10 diffraction of the specimen heated at 1550°C for 2h. The lattice constant (c<sup>0</sup>) and size of crystallite (L<sup>c</sup>) of the specimen were 6.735 and 220Å, respectively, after heating at 1550°C under atmospheric pressure for 2h. The size of crystallite increased from 320 to 830Å as the temperature increased from 1100°C to 1500°C under 2.0GPa for 10min heating. Boron nitride synthesized by heating at 800°C for 10h crystallized to hexagonal boron nitride when heated at 1500°C and 2.0GPa for 10min.
1 0 0 0 OA 回転型強度変調法による体幹部定位放射線治療中の対象内構造の同定と実線量分布の評価
本研究では放射線治療中の対象内の治療中のcone beam CT(CBCT)画像を取得可能であるガントリ回転型の強度変調放射線治療法を用いることによって,簡便かつ低侵襲に治療中の対象内の構造を同定し,治療装置の照射記録を用いることによって実際に標的に与えられた吸収線量および対象内の線量分布(実線量分布)を構築することを研究期間内目標とした.本研究の達成により実線量分布の評価法が構築され,放射線治療による腫瘍制御や正常組織のリスクの正当な評価につながる.