Carbide precipitation by Heating High-Manganese Steel after Solution Treatment

Carbide precipitations in isothermally and continuously heated Hadfield steel after solution-treatment were studied. Results obtained were as follows : 1. Solution-treated steel precipitated primary carbide isothermally in accordance with C-curve which has the nose at about 650～700℃, and also precipitated secondary pearlitic constituent isothermally with C-curve which has the nose at about 600℃. 2. At the primary stage, carbide films were formed at austenitic grain boundaries. In the low temperature range, carbide film formation delayed markedly, and then, platelet carbide were formed along the cleavage plane of grains. In the high temperature range, carbide films changed into granular particles and gradually took coherent shapes. 3. The nucleations of pearlitic constituents were most rapid at about 600℃, but growing velocity of pearlite has maximum value at about 500℃. 4. Secondary precipitates, pearlitic constituents, were very fine lamellar pearlite, and the lower temperature precipitates has the finer lamellar structure than precipitates at higher temperature. 5. In continuous heating, steel precipitated boundary carbides, platelet carbides and pearlitic constituents at about 500-600℃. It suggested that no pearlite precipitated when heated at a rate of above about 15℃/min and also no carbide precipitated when heated at a rate of above about 45℃/min. 6. Mechanical properties were injured by heating above about 350℃, since platelet carbide precipitations began at that temperature. Tensile strength lowered to minimum value at 750℃, since carbide films markedly grew at that temperature, and impact value, elongation and reduction of area lowered to minimum value at pearlite precipitation range. Increased hardness was affected mainly by platelet carbide precipitation

Phase Translation in Hadfield Steel Isothermally Heated at 500℃ after Solution Treatment

Hadfield steels isothermally heated at some temperatures undergo precipitations of grain boundary carbides. In steels with, precipitates grown up to a large amount, γ transformed into ε at about room temperature by cooling and theε-phase was present with carbides and α-phase. The equilibrium phases in a Hadfield steel at room temperature were reported to consist of α+carbide, but the process of phase translation leading to the equilibrium is not yet completely known. In the present work standard Hadfield steels of chemical composition of 13.7% manganese and 1.2% carbon and isothermally heated at 500℃ after solution treatment were studied mainly dilatometrically and magnetically. At 500℃, as well known, carbides first precipitated from γ-phase then γ transformed to carbide+α-phase, but it took a very long time to attain the equilibrium state. While in lower temperature it may be supposed that the γ-phase transformed in the following sequence : γ+carbide→γ+ε+carbide→γ+ε+α+carbide→+ε+α+carbide and finally to the equilibrium (α+carbide) in the long years. Thusε-phase in Hadfield steel is apparently metastable appearing only in phase transformation process to be equilibrium

ε-phase Formation in Solution-Treated and Heated Hadfield Steel

The effect of isothermal heating on the ε-phase formation is solution-treated standard Hadfield steel was studied. When solution-treated Hadfield steel was heated isothermally at some temperature range, it precipitated a large amount of grain boundary carbides and pearlitic constituents. Consequently, the carbon content in the γ-phase decreased, and then the γ-phase transformed into ε-phase after the specimens were cooled to room temperature. The isothermal temperature range of steels containing the ε-phase at room temperature was shown by a curve of C-form having the nose of 500℃×5 hr and ranging over 450～625℃. This range corresponds to that in which a large amount of pearlitic constituents precipitated. The existence of the ε-phase at room temperature was verified both by the microstructure and by the X-ray diffraction pattern. This ε-phase transformed into the γ-phase when the specimens were heated at 200～280℃, which was confirmed by a remarkable expansion in the thermal dilatation curve

レックリングハウゼン病の神経線維腫の病理発生に関する免疫電子顕微鏡的研究

金沢大学医学部研究課題/領域番号:02770615, 研究期間(年度):1990出典：研究課題「レックリングハウゼン病の神経線維腫の病理発生に関する免疫電子顕微鏡的研究」課題番号02770615（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-02770615/）を加工して作

冠動脈バイパス術患者における術前アスピリン投与中止時期の検討

研究科: 千葉大学大学院医学薬学府学位:千大院医薬博甲第医1081号博士(医学)千葉大

Structure and expression of two highly related genes encoding SCM-1/human lymphotactin

AbstractSCM-1/lymphotactin is a chemokine-like molecule produced selectively, if not exclusively, by activated CD8+ T cells. Here we report that there are two highly homologous SCM-1 genes, which we designate as SCM-1α and SCM-1β. Both genes have three exons and two introns. The 1st intron of SCM-1α contains a pseudogene of the ribosomal large subunit L7a. In SCM-1β, a 1.5-kb region including about a quarter of the L7a pseudogene is deleted from the 1st intron. Otherwise, the two genes are highly homologous including the 5′ and 3′ flanking regions. Both genes were mapped to human chromosome 1q23. The two genes were similarly induced in peripheral blood mononuclear cells by mitogenic stimulation. Primer extension and RNase protection revealed several transcription initiation sites. The biological activities of SCM-1α and SCM-1β, which have two amino acid differences at positions 7 and 8 in the mature proteins, remain to be compared