The role of the ceramics as a biomechanical material is very important in arrival of an aging society. Calcium phosphate cement (alpha-TCP) attracts attention for the purpose of medical treatment of a bone disease. And recently, comb-type superplasticizers with polyethylene oxide grafted pendant groups are used for producing self-compacting concrete and high strength concrete, and improving concrete durability in construction fields. This paper discusses the adsorption mechanism of comb-type superplasticizers and the influence of molecular structure of comb-type superplasticizers on the fluidity of alpha-TCP suspension.
The viscosity of the suspension was measured to estimate the apparent viscosity at a shear stress of 40 Pa. The adsorbed amount of polymer was calculated from the concentrations of the polymer in the initial solution and the liquid phase (after polymer adsorption). The unadsorbed polymer concentration was measured by Total Organic Carbon Analyzer (TOC).
As a result, the fluidity of alpha-TCP suspension was improved by using comb-type superplasticizers and it is considered that it is possible to reduce the water to powder ratio of alpha-TCP for the same fluidity. And by using rough and fine particles, the fluidity of paste is increased. The possibility of high strength of alpha-TCP was suggested.

抄録全体を表示

Corundum (Al₂O₃) crystals with a unique form have been successfully synthesized by the evaporation of MoO₃ flux at 1100°C. The grown crystals had a black color, and were up to 1.6×1.2 mm in size. Their form was a truncated bipyramidal tetradecahedron, bounded by twelve well-developed {1123} faces and two {0001} faces of sexangle. The sizes of the grown crystals were dependent on the solute contents. In this study, not Fe and Ti but Mo as a flux was found to be responsible for the characteristic black color.

抄録全体を表示

The shells were inorganic-organic composite material which 95 mass% of calcium carbonate and 5 mass% of protein overlapped alternately. The shape of calcium carbonate which composed various shells is plate or needle, and it is different from kinds of shells. Amounts of waste shells have a tendency to increase, and it is necessary for utilization of useful resources to recover calcium carbonate from waste shells. Separation of calcium carbonate from different shells was added to shell in NaOH solution of 1 mass%, and then prepared suspension of concentration of2.5-25 mass%. The suspension was treated by wet crushing under autoclave condition for 2-6 h at 25-140°C. The calcium carbonate obtained needle-like (length 10-30μm, width 0.5-2μm) from Scallop and Oyster shell, and plate-like (width 3-5μm, thickness 0.5μm) calcium carbonate from Turban shell.

抄録全体を表示

This paper reports the effect of heating temperature on luminescent color of bismuth (III) doped calcium sulfide (CaS) incorporated Na⁺ ion phosphor. When the CaS : Bi³⁺ incorporated Na⁺ phosphor was heated in the electric furnace while irradiating black light, emission wavelength of the phosphor measured with luminance meter increased linearly to near 460 °C. This originates for using the energy excited by the lattice vibration. The change of luminescent color from the blue to the green was observed over 380 °C in the human eye. The luminescent color charged from Blue to Greenish blue, when chromaticity diagram was used. This reproducibility by the repetition of the heating was good. However, the emission intensity of the phosphor, which repeated 5 times, decreased to 50% compared with that of the original sample.

抄録全体を表示

本研究では, 環境負荷の非常に小さいシリカゲル中での結晶育成方法を応用し, 再生医療分野において生体無機材料として非常に期待の高いアパタイトの前駆体であるリン酸八カルシウム (OCP : Ca₈H₂ (PO₄) ₆・5H₂O) 結晶を育成することを目的とした.リン酸水素ニナトリウム水溶液を添加したシリカゲル中に塩化カルシウム水溶液をゆっくりと拡散させ, カルシウムイオンとリン酸イオンを反応させることで, 乳白色のOCP球晶を育成した.4週間の育成期間後, 球晶の直径は約0.8mmに達した.走査型電子顕微鏡観察では, 板状OCP結晶が中心から放射状に成長して, OCP球晶を形成することが確認された.X線回折結果から, 球晶を構成する板状結晶の大きく発達した面の指数は {010} であることがわかった.

抄録全体を表示