The crystallization behaviors of poly (3-dodecylthiophene) (P3DDT) under two different oriented solidification conditions. i e..' two different relative relations (90° and 180°) between the directions of...The crystallization behaviors of poly (3-dodecylthiophene) (P3DDT) under two different oriented solidification conditions. i e..' two different relative relations (90° and 180°) between the directions of gravity and solidification. were investigated. X-ray diffraction results reveal that although similar layered structures are formed, under the condition of the relative relation 180°. temperature; gradient has greater effects on the perfect degree of the layered structures of P3DDT. It also can be concluded that after recrystallization. the layered structures of P3DDT can be improved at relative relation 90°, but the orderly degree of the arrangements of alkyl side chains are not improved yet, even is reduced for both of the oriented solidification conditions.展开更多
The crystallization behavior of poly (3-dodecylthiophene) (P3DDT) is studied bq differential scanning calorimetry (DSC) under different cooling rates. When the methods of Jeziorny., Ozawa and a new one proposed by our...The crystallization behavior of poly (3-dodecylthiophene) (P3DDT) is studied bq differential scanning calorimetry (DSC) under different cooling rates. When the methods of Jeziorny., Ozawa and a new one proposed by our laboratory are applied to describe its nonisothermal crystallization behavior, the new one is confirmed to be the best and convenient. By determining kinetic parameters, the analysis of the nonisothermal crystallization behavior is performed. According to Kissinger method, the crystallization activation energy of P3DDT is also evaluated.展开更多
Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prep...Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prepare eutectic single crystal ceramic with large size(30 mm×125 mm).A highly oriented and unique texture of Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramic is formed via the 112¯0Al_(2)O_(3) single crystal seed induction based on crystallographic orientation tailoring.The orientations of Al_(2)O_(3)/YAG eutectic are more strictly constrained by single crystal seed induction on the basis of the minimum interface energy principle,resulting in a defined single orientation relationship along the solidification direction.In particular,the single crystallographic orientation can be obtained in a short competitive solidification distance under the influence of epitaxial solidification from single crystal seed.Therefore,it has been confirmed that the orientations of 112¯0Al_(2)O_(3) and 111YAG are preferentially stabilized with the minimum under-cooling during directional solidification.Crystallographic orientation disturbances and instabilities due to polycrystalline crystal seed are avoided.Finally,the successful texture control inducted by 112¯0Al_(2)O_(3) single crystal seed can provide a promising orientation design pathway for faced oxide eutectic solidification.展开更多
文摘The crystallization behaviors of poly (3-dodecylthiophene) (P3DDT) under two different oriented solidification conditions. i e..' two different relative relations (90° and 180°) between the directions of gravity and solidification. were investigated. X-ray diffraction results reveal that although similar layered structures are formed, under the condition of the relative relation 180°. temperature; gradient has greater effects on the perfect degree of the layered structures of P3DDT. It also can be concluded that after recrystallization. the layered structures of P3DDT can be improved at relative relation 90°, but the orderly degree of the arrangements of alkyl side chains are not improved yet, even is reduced for both of the oriented solidification conditions.
文摘The crystallization behavior of poly (3-dodecylthiophene) (P3DDT) is studied bq differential scanning calorimetry (DSC) under different cooling rates. When the methods of Jeziorny., Ozawa and a new one proposed by our laboratory are applied to describe its nonisothermal crystallization behavior, the new one is confirmed to be the best and convenient. By determining kinetic parameters, the analysis of the nonisothermal crystallization behavior is performed. According to Kissinger method, the crystallization activation energy of P3DDT is also evaluated.
基金supported by the National Natural Science Foundation of China(Nos.52130204,52174376 and 51822405)the Guangdong Basic and Applied Basic Research Foundation(No.21201910250000848)+4 种基金the Science and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17)the Joint Research Funds of the Department of Science&Technology of Shaanxi Province and NPU(No.2020GXLH-Z-024)The Youth Innovation Team of Shaanxi Universities,the Key R&D Program of Shaanxi Province(No.2019ZDLGY 04-04)the Fundamental Research Funds for the Central Universities(No.D5000210902)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Nos.CX2021056,CX2021066 and CX2022033),China.
文摘Crystallographic texture control is a major challenge in directionally solidified multiphase eutectic ceramics with complex faceted growth characteristics.In this study,the Czochralski(CZ)technique is proposed to prepare eutectic single crystal ceramic with large size(30 mm×125 mm).A highly oriented and unique texture of Al_(2)O_(3)/Y_(3)Al_(5)O_(12)(YAG)eutectic ceramic is formed via the 112¯0Al_(2)O_(3) single crystal seed induction based on crystallographic orientation tailoring.The orientations of Al_(2)O_(3)/YAG eutectic are more strictly constrained by single crystal seed induction on the basis of the minimum interface energy principle,resulting in a defined single orientation relationship along the solidification direction.In particular,the single crystallographic orientation can be obtained in a short competitive solidification distance under the influence of epitaxial solidification from single crystal seed.Therefore,it has been confirmed that the orientations of 112¯0Al_(2)O_(3) and 111YAG are preferentially stabilized with the minimum under-cooling during directional solidification.Crystallographic orientation disturbances and instabilities due to polycrystalline crystal seed are avoided.Finally,the successful texture control inducted by 112¯0Al_(2)O_(3) single crystal seed can provide a promising orientation design pathway for faced oxide eutectic solidification.
