巻号一覧
前身誌
1979 巻, 159 号
選択された号の論文の6件中1～6を表示しています
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吉良 欣一, 間木野 義雄, 山本 博一1979 年 1979 巻 159 号 p. 48-53
発行日: 1979/03/01
公開日: 2011/03/07
ジャーナル フリーIn order to clarify the stability of hardened body containing ettrigite, studies were made to synthesized ettringite and examined its carbonation mechanism by means of differential thermal analysis, thermal gravimetric analysis, X-ray diffractometry, infra-red absorption spectroscopy and electron microscopic observation. The results obtained are as follows :
(1) Carbonation of ettringite proceeds easily and only gypsum as a crystalline substance and an amorphous phase containing carbonates are recognized to produce as the resultant.
(2) Gypsum formed by carbonation of ettringite is covered with amorphous materials.
(3) The reaction of ettringite proceeds rapidly in ordinary air-drying conditions, but somewhat slowly in wet conditions (10% water in weight of ettringite).
(4) The mechanism of carbonation is discussed from a type of dissolution-recrystallization.抄録全体を表示PDF形式でダウンロード (1215K) -
門間 英毅, 上野 精一1979 年 1979 巻 159 号 p. 53-58
発行日: 1979/03/01
公開日: 2011/03/07
ジャーナル フリーThe thermal dehydration process of a nonstoichiometric hydroxyapatite having Ca10-z (HPO4) z (PO4) 6-z (OH) 2-z·nH2O [z≅0.82, n≅1.43] was characterized by measuring weight loss during continuous heating (TG) up to 800°C and isothermal heating from 100 to 800°C at intervals of 50°C. Partly the DTA method was used for estimating the heat of decomposition (ΔH) of the apatite into β-Ca3 (PO4) 2.
The dehydration process was divided into five regions. The regions were summarized as follows by using terms of dehydrated fraction (W), temperature, apparent activation energy (E) and ΔH; (I) : W<20% (<150°C), (II) : W= 20-45% (150-350°C) and E= 20-30 kcal/mol, (III) W= 45-75% (350-600°C) and E=40-50 kca1/mol, (IV) : W=75-80% (600-700°C) and E≅95 kcal/mol, (V) : W=80-100% (700-800°C) and E≅105 kcal/mol, ΔH=20-30 kcal/mol. Weight loss on the isothermal heating in the range 100-700°C quickly attained to apparent equilibrium depending upon each temperature.
This feature led to an approximate coincidence between weight losses by TG and the isothermal method. Therefore, slopes of the TG curve in the range below 700°C were considered to reflect the maximum dehydration rates at corresponding temperatures.抄録全体を表示PDF形式でダウンロード (857K) -
佐伯 雄造, 松崎 〓子, 小林 敏昭, 升水 萩男1979 年 1979 巻 159 号 p. 59-65
発行日: 1979/03/01
公開日: 2011/03/07
ジャーナル フリーThe method for preparing anhydrous MgSO3 from MgS03·6H2O was examined. Thermogravimetry and differential thermal analysis of MgSO3 in an argon stream were carried out. The decomposition products of MgSO3 at various temperatures were examined in detail by chemical analysis and X-ray diffractometry. The decomposition of MgS2O3, formed during the decomposition process of MgSO3, on heating was also examined.
MgSO3 decomposes above about 80°C with the evolution of gaseous SO2. The products obtained in the heating zone were MgO at 80-250°C, MgO, β-MgSO4, and MgS2O3 at 300-500°C, and MgO and β-MgSO4 at 525-550°C. Sulfur was also obtained outside the heating zone above 400°C. MgS2O3 decomposes as early as 300°C to form MgSO3 and sulfur.
From these results, the thermal decomposition process of MgSO3 can be represented as follows : The decomposition of MgSO3 proceeds above about 80°C according to the reaction, MgSO3→MgO+SO2.Above about 300°C, the reaction, 4MgSO3→2MgSO4+MgS2O3+MgO, occurs in addition to the above reaction. Subsequently, the decomposition of MgS2O3 formed, MgS2O3→MgSO3+S, occurs.抄録全体を表示PDF形式でダウンロード (905K) -
Michel MURAT, 飯田 貴也, 瀬戸山 克己1979 年 1979 巻 159 号 p. 66-71
発行日: 1979/03/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (1305K) -
村橋 均次郎1979 年 1979 巻 159 号 p. 71-74
発行日: 1979/03/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (525K) -
1979 年 1979 巻 159 号 p. 80
発行日: 1979年
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (115K)
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