巻号一覧
50 巻 (2023)
- 4 号 p. 126-
- 3 号 p. 89-
- 2 号 p. 63-
- 1 号 p. 1-
50 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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小林 比呂志, 高橋 東之2023 年 50 巻 2 号 p. 63-69
発行日: 2023/04/25
公開日: 2023/05/01
ジャーナル 認証ありThe glass transition has been observed using apparatuses for viscosity and calorimetry measurements. We developed a new method which can measure a high viscosity of an equilibrated glass using the same specimen in a whole temperature range near the glass transition temperature (Tg). The glass transition was discussed using obtained data based on the Adam-Gibbs theory. We propose a new model of intermediate-range orders (IROs) such as cooperatively rearranging regions (CRRs). After IROs emerge at the mode coupling temperature (Tc) due to a cage effect in a supercooled liquid, IROs freeze at Tg to make a glass state. A glass relaxes to an ideal glass during prolonged aging due to the enthalpy recovery below the Kauzmann temperature (TK). An ideal glass reaches to an polycrystal during an extremely long time due to the structural recovery. An ideal glass has the dissipative structure in a nonequilibrium steady state, which was presented by Prigogine.抄録全体を表示PDF形式でダウンロード (808K) -
新津 甲大2023 年 50 巻 2 号 p. 70-75
発行日: 2023/04/25
公開日: 2023/05/01
ジャーナル 認証ありAs an alternative to conventional gas-compression cyclic cooling, caloric effects through solid-solid phase transformations/transitions offer an innovative platform as an environmentally friendly cooling technique. Among the various types of caloric effects, the elastocaloric effect has garnered significant attention. This technique exploits the large latent heat associated with ferroelastic transformations, typically superelasticity, which refers to the stress-induced reversible thermoelastic martensitic transformations that exhibit a large recoverable strain. In this review, the fundamental mechanism of elastocaloric cooling is reviewed with addressing the fundamental phenomenology of superelasticity in shape-memory alloys. To evaluate the elastocaloric cooling performance associated with superelasticity, a phase diagram in the stress-induced martensitic transforming systems is informative. This review guides the way to quantitatively evaluate the two factors that primarily determine the performance as an elastocaloric cooling material: the entropy change and dissipation heat. This demonstration is done for the prototypical shape-memory alloys of Ti-Ni and Cu-Al-Mn alloys. More specifically, the low-temperature operation of superelasticity and the potential of associated elastocaloric cooling effect are discussed in terms of the balance between the entropy change and dissipation heat. Finally, the cooling performance of various kinds of caloric materials is compared and the challenges, and prospects of shapememory materials as solid-state cooling materials are addressed.抄録全体を表示PDF形式でダウンロード (1795K) -
武田 貴志, 芥川 智行2023 年 50 巻 2 号 p. 76-84
発行日: 2023/04/25
公開日: 2023/05/01
ジャーナル 認証ありDesign of structure and electronic properties of organic molecules have been achieved through organic synthesis. On the other hand, connection of such unique structure and assemblies to unique novel function is still difficult, especially in dynamic molecular assembly. Utilization of molecular motion in the assembly could develop new functional organic material. Herein, we introduce our recent work on unique functional organic materials based on molecular motion in the condensed phases. Rotation of one-dimensional amide hydrogen-bonding chain of arenealkylamide derivatives in response to external electric field afforded ferroelectricity. Collective and anisotropic molecular motion of twisted π molecule induced mechanical force in response to external heating (thermosalience). A variety of molecular motions is possible in organic molecules, which has different mode of motions and activation energies. With consideration of such factors, materials with new function could be proposed through the assemblies of molecules with appropriate arrangement and degree of freedom of molecular motion. Coupling molecular motion with its electronic, photophysical properties in the assemblies could develop new multifunctional organic molecular materials.抄録全体を表示PDF形式でダウンロード (2064K)
フロギストン
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2023 年 50 巻 2 号 p. 85
発行日: 2023/04/25
公開日: 2023/05/01
ジャーナル 認証ありPDF形式でダウンロード (187K)
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