巻号一覧
44 巻 (2017)
- 4 号 p. 135-
- 3 号 p. 77-
- 2 号 p. 55-
- 1 号 p. 1-
44 巻, 2 号
選択された号の論文の4件中1～4を表示しています
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解説
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猿山 靖夫, 盛脇 荘太郎, 和田 将大, 八尾 晴彦2017 年 44 巻 2 号 p. 55-59
発行日: 2017/04/25
公開日: 2022/11/20
ジャーナル フリーThe heat capacity of polytetrafluoroethylene (PTFE) crystal around the phase transition temperatures have been measured with a new type of high pressure ac calorimeter developed in the authors' laboratory. Atemperature-pressure phase diagram was proposed. The phase II undergoes the phase transitions on the heating process to the phase IV (0.1 - ca. 200 MPa), the phase I (ca. 200 – ca. 400 MPa), the phase I' (ca. 400 – ca. 500 MPa) and the phase III (higher than ca 500MPa). At pressures lower than 200 MPa the phase IV further changes to the phase I. Based on the temperature dependence of the heat capacity the phase transitions from the phase II to the phases IV, I and I' were attributed to the order-disorder type. The structure of the phase diagram suggested that the phase I and the phase I' were thermodynamically close to each other. This was consistent with the vanishing of the boundary between the phase I and phase I' in the middle of the region of the phase I. The temperature dependence of the heat capacity around the phase transition to the phase III was notably different from the transitions to the phase IV, I and I'. Nature of the phase III was discussed in comparison with the high pressure phase of polyethylene.抄録全体を表示PDF形式でダウンロード (1122K) -
瀧上 隆智, 平城 慎也2017 年 44 巻 2 号 p. 60-64
発行日: 2017/04/25
公開日: 2022/11/20
ジャーナル フリーOne of the fascinating subjects in the researches in soft interfaces including liquid/liquid interfaces is heterogeneity of interfacial films, because it is of importance to understand the domain formation such as “raft” in biological membranes. In this study, the domain formations in the adsorbed films at the hexane/water interface were examined by interfacial tensiometry and X-ray reflection (XR). The adsorbed F8H2OH film shows an expanded – condensed phase transition. The expanded state is heterogeneous film in which the condensed domain coexists with low density gaseous region. The domain coverage strongly depends on the line tension acting on the domain boundary. In the mixed F8H2OH – F6H6OH system, the expanded – condensed phase transition becomes obscure with increasing the fraction of F6H6OH in the adsorbed film. XR analysis indicated that the coverage of condensed F8H2OH domain increases and the size of the domain decreases by mixing of F6H6OH with F8H2OH in the adsorbed film. This is probably due to the reduction of domain line tension by preferential adsorption of F6H6OH at the F8H2OH domain boundary. Furthermore, the domain formation in the mixed C14PC – Cholesterol film was examined by coupling the 2D phase diagram and XR data analysis.抄録全体を表示PDF形式でダウンロード (1679K) -
菱田 真史2017 年 44 巻 2 号 p. 65-71
発行日: 2017/04/25
公開日: 2022/11/20
ジャーナル フリーBiomembranes of cells are mainly composed of phospholipid bilayers, including various kinds of small organic molecules. To understand widely the effects of these small molecules on a phospholipid bilayer, systematization of the effects is desired with focusing on the molecular structures of the additive molecules. Cholesterol is well known to disturb the molecular ordering of a lipid bilayer in the gel (Lβ' and Pβ') phases, resulting in softening of the bilayer and lowering of the transition temperature between Pβ' and Lα phases. On the other hand, in the present study, we found n-alkane makes the molecular arrangement more ordered in the Lβ' phase, resulting in rigidification of the bilayer and raise of the transition temperature. Bulky core-like molecules such as cholesterol and the molecules with a linear and flexible chain contrastingly affect the bilayers due to the contrary effects on the ordering of acyl chains in the bilayer. Indeed, cis-stilbene, the bulkier molecule, disturbs the acyl chains more largely than the trans-isomer, lowering the transition temperature more drastically. When a core part and an alkyl chain coexist in a molecule like nCB, the effects of these parts compete each other. The effect of a whole molecule changes depending on the length of an alkyl chain.抄録全体を表示PDF形式でダウンロード (1514K)
フロギストン
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2017 年 44 巻 2 号 p. 72-73
発行日: 2017/04/25
公開日: 2022/11/20
ジャーナル フリーPDF形式でダウンロード (622K)
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