巻号一覧
1988 巻 (1988)
- 217 号 p. 397-
- 216 号 p. 257-
- 215 号 p. 197-
- 214 号 p. 129-
- 213 号 p. 61-
- 212 号 p. 3-
前身誌
1988 巻, 216 号
選択された号の論文の14件中1～14を表示しています
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荒井 康夫, 安江 任1988 年 1988 巻 216 号 p. 257-279
発行日: 1988/09/01
公開日: 2011/08/16
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坂根 幸治, 北村 孝雄, 小川 淳1988 年 1988 巻 216 号 p. 281-287
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーFormation process of fibrous magnesium pyroborate (Mg2B2O5) and an effect of KCl flux in the formation were investigated by TG-DTA, X-ray powder diffraction and SEM.
A mixture of raw materials, which consisted of MgO, H3BO3 and KCl with a 2 : 3 : 5 mole ratio, mostly dehydrated at 250°C. The formation of Mg2B2O5 took place at temperatures above 500°C. At 650 and 750°C Mg2B2O5 and magnesium tetraborate (MgB4O7) were observed as expected from the phase diagram of MgO-B2O3, but both compounds were irregular in shape.At 850°C MgB4O7 decomposed and needle-like monoclinic Mg2B2O5 was formed.
Very low solubility of Mg2B2O5 in KCl flux suggested that the needle-like Mg2B2O5 was formed by the ripening mechanism in liquid phase of KCl.抄録全体を表示PDF形式でダウンロード (2006K) -
椚座 圭太郎, 槻山 興一, 寺村 敏史, 湯田 周二, 井須 紀文, 庄司 哲雄, 高橋 秀明1988 年 1988 巻 216 号 p. 288-294
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーXonotlite fiber was synthesized by direct precipitation method with continuous-type autoclave. It was also formed by normal method with batch-type autoclave for comparison, under which the transformation of CSH to tobermolite followed by tobermolite to xonotlite occurs. Direct precipitation method includes two processes, (1) rapid heating of raw materials inhibiting the nucleation of CSH and tobermolite, and (2) in-situ mixing of raw at the condition of xonotlite formation, thereby only nuclei of xonotlite are formed. These processes resulted in the rapid growth of xonotlite with a maximum length of 2 mm at 350°C and 5 hours. Preliminary measurement shows the tensil strength of the present xonotlite to be 70 kg/mm2. In the continuous-type autoclave, the formation of xonotlite proceeded irrespective of the Ca/Si ratio and the concentration of minor elements of raw materials, and hence it is considered that the reaction occurred in open system and xonotlite is a primary phase at the present condition.抄録全体を表示PDF形式でダウンロード (993K) -
安江 任, 瀬高 俊哉, 梅澤 英之, 荒井 康夫1988 年 1988 巻 216 号 p. 295-304
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーTobermorite as fibrous CaO-SiO2-H2O compound is generally synthesized by hydrothermic reaction at high temperatures over 180°C but produced from unhomogeneous mixture between CaO (solid), SiO2 (solid) and H2O (liquid).
Study was made to synthesize fibrous CaO-SiO2-H2O compound at comparatively low temperatures of 60-95°C under atmospheric pressure after completely homogeneous mixing CaCl2+HCl (liquid) and Si (OC2H5) 4+C2H5OH (liquid) in atomic ratio Ca/Si 0.8-1.2 as required.
The homogeneous mixture of Ca/Si ratio 0.8 1.2 as liquid phase was rapidly converted to gelatinous state by adding KOH or NH4OH solutions. Then the gelatinous suspension (pH 7.5-11.0) was aged at 60-95°C for 1-21 days to crystallize as fibrous state. Atomic ratio Ca/Si of the CSH gel was almost equal to starting Ca/Si ratio at pH 11.0 controlled by KOH solution and free lime was not found in the gel.
The crystallization and fibrousfication of the CSH gel were very affected by the synthetic conditions such as starting Ca/Si ratio 1.2, 95°C and pH 11.0, plate-like 11Å tobermorite was crystallized from the gel after 7 days and after 3 days with additive Al3+. Otherwise, in the case of Ca/Si ratio 0.8, the crystallization of 11Å tobermorite was depressed by adsorption of K+ and fibrous tobermorite gel grew up (aspect ratio 60-120) from the gel so that K+ effectived as accelerator for fibrous crystal.抄録全体を表示PDF形式でダウンロード (1916K) -
青木 繁樹, 鉄羅 義徳, 荒井 康夫1988 年 1988 巻 216 号 p. 305-313
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーIn the reaction of slag (granulated blast-furnace slag) with sulfuric acid, gypsum (calcium sulfate dihydrate) is formed and the Al2O3 component and the SiO2 component in slag are activated. The addition of calcium hydroxide into the slag treated with sulfuric acid will result in the formation of ettringite (3 CaO·Al2O3·3 CaSO4·32H2O) and calcium silicate hydrate at relatively low temperature.
Study was made on the influence of the contents of calcium hydroxide in the system of slag-H2SO4-Ca (OH) 2 (slag-sulfuric acid-calcium hydroxide) and the addition of KOH into the system on the formation of fibrous calcium silicate hydrate under 100°C. The results obtained were as follows.
The products formed under 50°C were composed of ettringite and calcium silicate hydrate as needle-like. The ettringite decomposed into low calcium sulfoaluminate (3 CaO·Al2O3·CaSO4·12H2O) and gypsum at 80°C, but fibrous products began to form in the system. Fibrous calcium silicate hydrate formed relatively easily at 100°C in the system of slag-H2SO4-Ca (OH) 2.
The adequate condition of synthesizing fibrous calcium silicate hydrate was as follows. The composition of calcium hydroxide in the system were 1.0 of Ca/Si as atomic ratio and the addition of KOH was 0.1 of KOH/slag as weight ratio. The slurry of the system of slag-H2SO4-Ca (OH) 2-KOH was kept at 100°C for 3 days.抄録全体を表示PDF形式でダウンロード (1988K) -
田中 宏一, 堀内 秀樹, 大久保 勉1988 年 1988 巻 216 号 p. 314-321
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーThree crystal forms of CaCO3, calcite, aragonite and vatelite are well-known. Synthesized aragonite is crystallized as needle-like shape. Investigation were made on the crystal growth of those needle-like CaCO3 produced from the solution of milky lime through blowing CO2 with perfect mixing by continuous reactor. The results obtained are as follows.
1. Both pH and reaction temperature affect shape of CaCO3.
At reaction temperature under 50°C, cubic calcite is formed in the range of pH from 6 to 8, and from 9 to 11. But in pH range between 8 and 9, spindle calcite is formed.
At reaction temperature over 50°C, cubic calcite is formed in pH ranging from 6 to 8 and from 9 to 11, but in pH range between 8 and 9, needle-like is formed.
2. Addition of seed crystals controls the size of needle-like aragonite.
3. Both CO2 concentration in reaction gas and Ca (OH) 2 concentration in slaked lime slurry scarcely affect the degree of crystal growth of needle-like CaCO3.抄録全体を表示PDF形式でダウンロード (2053K) -
萩原 宏, 永田 憲史1988 年 1988 巻 216 号 p. 322-329
発行日: 1988/09/01
公開日: 2011/03/07
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瀬戸山 克己1988 年 1988 巻 216 号 p. 330-334
発行日: 1988/09/01
公開日: 2011/03/07
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吉田 康史, 山口 修二1988 年 1988 巻 216 号 p. 335-341
発行日: 1988/09/01
公開日: 2011/03/07
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藤木 良規1988 年 1988 巻 216 号 p. 342-351
発行日: 1988/09/01
公開日: 2011/03/07
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電磁波シールド材料大澤 善次郎1988 年 1988 巻 216 号 p. 352-358
発行日: 1988/09/01
公開日: 2011/03/07
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元井 操一郎1988 年 1988 巻 216 号 p. 359-367
発行日: 1988/09/01
公開日: 2011/03/07
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羽田 三郎1988 年 1988 巻 216 号 p. 368-374
発行日: 1988/09/01
公開日: 2011/03/07
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高田 武雄1988 年 1988 巻 216 号 p. 375-385
発行日: 1988/09/01
公開日: 2011/03/07
ジャーナル フリーPDF形式でダウンロード (1124K)
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