After the Meiji Restoration, the new government established Hiroshima Foreign Language School, one of the seven foreign language schools, in 1874. It altered its name into Hiroshima English School and was succeeded by Hiroshima Prefectural English School in 1877.
The two old documents of Annual School Bulletin in 1875 and in 1876 reveal in this thesis the names of Principal Torataro Yoshimura, Rev. Mr. Christopher Carrothers, and Mr. Tateki Owada, who came from Uwajima to be a famous poet later, among 55 students from Ehime Perfecture. Mr. Tsuji's curriculum vitae clearly shows us the educational standard of English studies at Hiroshima English School and other higher educational institutions.

抄録全体を表示

格子熱伝導度は，材料の断熱性や放熱性を決定付ける重要な物性である．近年，材料の断熱性を向上させる取り組みとして，結晶粒界で生じる熱抵抗を積極的に活用したナノ多結晶体が熱電変換などの分野で盛んに作製されている．しかしながら，その熱伝導度の低下機構は十分に明らかにされていない．具体的には，粒界構造と熱伝導度の相関，ナノ多結晶化による粒内フォノン散乱，結晶粒の形状が熱伝導に与える影響など，多くの不明点がある．本稿では，原子レベルの計算科学手法や構造記述子などの情報科学的手法を用いて，これらの不明点を微視的観点から解明した研究例を2つ紹介する．

抄録全体を表示

　円筒状の炭素繊維強化プラスチック（Carbon Fiber Reinforced Plastic：CFRP）をロールシェルとして使用したロールは“カーボンロール”と呼ばれ，鉄，アルミと並ぶ第三のロールとして定着してきた。近年の製紙機械は紙幅10m程度にまで広幅化しており，運転速度は2,000m/minのレベルになっている。広幅で高速という条件は，装置内のロールにとっては正に過酷な条件であり，それを克服するためにカーボンロールが採用されている。しかし，ただ単にカーボンロールを使えばよいと言うわけにはいかない。高速安定運転を実現するためには，適正な設計に基づいて，かつその設計を高度に具現化する製造技術により製造されたカーボンロールが必須となる。
　本稿ではカーボンロールの原料として最適な超高弾性率ピッチ系炭素繊維を用いた高速・広幅製紙機械向けロールの設計の考え方を説明し，次に我々が提案する動フレの抑制技術について具体的な測定データを交えて紹介する。これらを踏まえて面長10mL，抄速2,000m/minの製紙機械向けのロールの設計を行ってみたところ，鉄ロールと比較して，（１）　ロール径は1/2，（２）　重量は1/6，（３）　慣性モーメントは1/25に低下させることが出来る事が分かった。当該ロールを採用することにより，著しい小径化・軽量化・低慣性モーメント化が達成され，製紙機械のコンパクト化，省エネ，そして何よりも安定したロール回転による安定操業に貢献することができる。

抄録全体を表示

Systematic atomistic simulations of homo- and hetero-phase boundaries have been carried out to quantify interphase boundary energies in iron including δ-phase and γ-phase grain boundaries and δ/γ, δ/liquid and γ/liquid interfaces. Due to structural mismatch between body centered cubic (BCC) and face centered cubic (FCC) structures of the δ and γ phases, the minimum interface energy of the δ/γ interface is as high as 0.41 J/m², much higher than the minimum interface energies of the δ/δ and γ/γ homo-phase interfaces, which are zero, suggesting that the high interface energy is one of the key factors that lead to the massive-like phase transformation from the δ phase to the γ phase observed by in situ radiography. Although the minimum δ/γ interface energy is not significantly higher than the δ/liquid interface energy that determines the δ nucleation upon solidification, it is yet high enough for the small entropy change upon the phase transformation to inhibit γ nucleation at a given critical radius until more than one orders of magnitude higher undercooling is achieved according to the classical theory of homogeneous nucleation.

抄録全体を表示

Time-resolved and in-situ observation of solidification by X-ray imaging is a powerful method to empirically understand the solidification process of metallic materials. Observations began with low-melting-point alloys such as Al, and were later applied to the observation of Fe-based alloys in the temperature range above 1750 K. In Ti–Al binary system, there is a γ phase (TiAl intermetallic compound) in addition to an α phase and a β phase, which results in a relatively complex phase diagram with multiple peritectic solidification. Therefore, although there are various possibilities for phase selection and microstructure formation during the solidification process, the solidification process has not been empirically clarified. Therefore, we used single crystal MgO as the sample holding container to suppress the reaction with the reactive molten Ti as much as possible, and for the first time, we successfully observed the solidification process of TiAl alloys. Time-resolved and in-situ observations showed that a solid state phase transformation with repeated nucleation and growth was selected instead of the peritectic solidification from α to γ phases shown in the Ti–Al binary phase diagram. The α/γ transformation should also be taken into account in TiAl alloys, since the α/γ transformation formed a fine γ phase and affected the microstructure formation. This understanding of the α/γ transformation was expected to provide new guidelines for controlling the solidification structure of TiAl alloys.

抄録全体を表示

Effective interface energies of various homo- and hetero-interfaces of iron were calculated with an aid of phase-field modeling, taking into account geometric constraints by competition among grains or interfaces. Calculated effective interface energies for δ/γ, δ/δ, and γ/γ interfaces are 0.56, 0.44 and 0.37 J/m², respectively. Using two simple geometric models for nucleation on or off an interface in the matrix, the optimal shape of a nucleus at a given radius and undercooling, a critical radius and an energy barrier for nucleation for each possible circumstance were numerically calculated. It is found that, although the energy barrier for γ-phase nucleation in homogeneous δ-phase matrix is more than three orders of magnitude greater than that for homogeneous solidification of δ-phase, the γ nucleation on a δ/δ grain boundary in the solidifying matrix suppresses the energy barrier, increasing a nucleation rate. Furthermore, it is found that the γ-phase nucleation on an existing γ nucleus halves undercooling needed with smaller critical radius. This suggests that, once γ nucleation is initiated, then following γ nucleation is promoted by doubled driving force, enabling multiple γ nucleation as in chain reaction. These findings are sufficient to explain experimentally observed phenomena during the δ-γ massive-like phase transformation even if other factors such as solute re-distribution or transformation is neglected.

抄録全体を表示

It has been realized that a massive-like transformation, in which δ phase (ferrite) transformed to γ phase (austenite) in the solid state during and after solidification, was selected in Fe–C steels. X-ray radiography confirmed that the massive-like transformation also occurred in Fe-18 mass%Cr-Ni alloys with Ni contents of 8, 11, 14 and 20 mass%Ni. According to the equilibrium phase diagram, δ phase is the primary phase in 8 and 11 mass%Ni alloys while γ phase in 14 and 20 mass%Ni alloys. Solidification was always initiated by nucleation of δ phase and consequently fine γ grains were formed by the massive-like transformation in 8 and 11 mass%Ni. On the other hand, nucleation of δ phase as a metastable phase was preferably selected at lower undercoolings (<50 K) in 14 and 20 mass%Ni and consequently the massive-like transformation occurred even in 14 and 20 mass%Ni alloys. Solidification of γ phase can be triggered by nucleation of δ phase followed by the massive-like transformation in the Fe–Cr–Ni with lower Cr/Ni values (the primary γ alloys). Moreover, the present study demonstrates that the massive-like transformation will be commonly observed in Fe-based alloys, in which δ and γ phases are competitive each other from a thermodynamic perspective.

抄録全体を表示

A new type of constitutional abnormity“Anenzymia Catalasea”was described by S. Takahara and M. for the first time. In most of this abnormity it can be noticed that patients suffer from peculiar gangrenous inflammation, either mild or severe, over the oral mucosa, caused by bacterial infection, in the beginning of the disease, which has a resemblance to alveolar pyorrhoea, but much more malignant symptoms. A 55-year-old male farmaer showing a slight symptom of this disease is presented in this report.

抄録全体を表示

炭素繊維強化プラスチック（CFRP）製ロールはカーボンロールと呼ばれ，金属製ロールと比較して，軽量，低慣性モーメント，高剛性等の優れた特性を持つことから，近年ではフィルム製造，製紙，印刷業界等の各種産業分野に適用が広がっている。特に製紙分野では近年，生産性向上，コスト削減を目的として，製造ライン速度の高速化，抄紙サイズの幅広化が進められている。これに伴ってラインを構成している各種ロールにおいては，軽量化，高剛性化，小径化が求められている。
しかし，カーボンロール表面は耐摩耗性，搬送ウェブとの摺動特性などからCFRPそのままで使用されることは殆どない。我々は長年に亘る研究開発の結果，溶射プロセスによるカーボンロール表面への各種材料の被覆技術を確立した。これら溶射カーボンロールは各種産業界で非常に高いロール性能，表面性能を必要とされる部位に適用されつつある。
本稿ではカーボンロールへの溶射技術とワインダーマシンのセクショナルロールに軽量，高剛性のCFRPをシェル基材とし，ロール表面に耐摩耗性，グリッピング特性を与えるWCサーメット溶射皮膜を施したカーボンロールを適用した事例について報告する。

抄録全体を表示

In-situ observation of deformation in semi-solid alloys at the grain scale has been carried out using X-ray radiography. This paper characterizes the deformed microstructure in the semi-solid state by a quantitative analysis of solid motion from the image sequences obtained by the in-situ experiment on semi-solid Al-Cu alloys. A velocity of solid, a shear strain rate and a divergence of solid rate, which correspond to the change in solid fraction, were evaluated during a 0.5-1d (d: crystal size) increment of direct shear. The effect of solid morphology on the shear deformation was also examined by in-situ observation of deformation in water-polystyrene particle mixture where the polystyrene particles are spherical (shape factor~1) with diameter of 500 μm. The shear strain was localized in the vicinity of the shear domain and the localized area corresponds to the area where the solid fraction decreased both in semi-solid Al-Cu alloys and the water-particle mixture. The waterpolystyrene particle mixture showed a narrower localized area of the shear strain than that of Al-Cu alloys due to the difference in the solid shape.

抄録全体を表示

Time-resolved and in-situ observations using synchrotron radiation X-rays successfully proved that the massive-like transformation, in which the γ phase was produced through the solid – solid transformation and the partition of substitute elements such as Mn and Si at the δ/γ interface could be negligibly small, was selected in the unidirectional solidification of 0.3 mass%C steel at a pulling rate of 50 μm/s. The massive-like transformation produced fine γ grains in the vicinity of the front of δ/γ interface. The coarse γ grains also grew behind the fine γ grains along the temperature gradient. Distance between the δ/γ front and the advancing front of coarse γ grains was as short as 200 μm. Namely, the fine γ grains disappeared within 10 s by the growth of coarsen γ grains along the temperature gradient. In addition, the observation of the δ/γ interface confirmed that a transition from the diffusion-controlled γ growth to the massive-like growth of γ phase occurred at a growth rate of 5 μm/s. Thus, the massive-like transformation is dominantly selected in the carbon steel during conventional solidification processes.

抄録全体を表示

Synchrotron X-ray radiography was used to study tensile and compressive deformations of semi solid Al-Cu and/or Fe-C alloys. In the case of tensile deformation of globular Al-Cu sample at ~60% solid, relatively high strain regions were formed even at mean strain of 0.005. The normal strain rate at the regions was 10 times as high as mean normal strain rate (3.45×10^–3 s^–1). At mean strain of 0.04, tensile deformation was localized in the high strain region, resulting in the formation of internal cracking in the plane normal to the tensile axis. On the other hand, in the case of compressive deformations of globular Al-Cu sample at ~55% solid and polygonal Fe-C sample at ~73% solid, shear bands with decreased solid fraction were formed at the domains tilted by approximately 45 degrees with respect to compressive plane. Rearrangement of solid particles including translation and rotation caused the shear induced dilation at the shear domains. Shear strain was localized at the shear domain with decreased solid fraction. Deformation of the polygonal solid particle of Fe-C sample caused a force to transmit over a longer distance than for the globular Al-Cu sample. Shear fracture finally occurred due to inadequate liquid flow into the expanding spaces between solid particles caused by shear-induced dilation. The solid/solid interaction including impingement between solid particles and rearrangement has significant role in the compressive deformation. These observations demonstrated that the mechanism of cracking formations induced by compressive deformation was totally different from that in the tensile deformation.

抄録全体を表示

Time-resolved and in-situ observations using synchrotron radiation X-rays successfully proved that a massive-like transformation, in which the γ phase was produced through the solid–solid transformation and partitioning of substitute elements such as Mn and Si at the δ–γ interface was negligible, was selected in the unidirectional solidification of 0.3 mass% C steel at a pulling rate of 50 µm/s. The massive-like transformation produced fine γ grains near the front of the δ–γ interface. The coarse γ grains also grew behind the fine γ grains along the temperature gradient. Distance between the δ–γ front and the advancing front of coarse γ grains was as short as 200 µm. Namely, the fine γ grains disappeared within 10 s owing to growth of coarse γ grains. In addition, the observation of the δ–γ interface confirmed that a transition from the diffusion-controlled γ growth to the massive-like γ growth occurred at a growth velocity of 5 µm/s. Thus, the massive-like transformation is dominantly selected in the carbon steel during conventional solidification processes.

抄録全体を表示