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自由能图及其应用
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作者 杨光 《宿州师专学报》 2002年第2期112-113,共2页
本文从自由能和标准电报电位的联系入手,说明自由能图的绘制方法,阐明依据自由能图判断反应自发性比较物质性质等方面的应用。
关键词 自由能 自由能图 绘制 应用 标准电报电位
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Thermodynamic modeling of ZrO_(2)−CaO−TiO_(2)system
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作者 Shi-yu HE Qi-sheng FENG +4 位作者 Bao-hua DUAN Guang-yao CHEN Zhu WU Chong-he LI Xiong-gang LU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期696-708,共13页
The phase diagram of ZrO_(2)−CaO−TiO_(2)system was essential for the development of photocatalytic materials and refractory materials.In this work,the ZrO_(2)−CaO−TiO_(2)system was accessed by using the CALPHAD method... The phase diagram of ZrO_(2)−CaO−TiO_(2)system was essential for the development of photocatalytic materials and refractory materials.In this work,the ZrO_(2)−CaO−TiO_(2)system was accessed by using the CALPHAD method.The substitutional solution models were used to describe liquid and solid solution phases,the sub-lattice models were used to describe ternary compounds,and then the thermodynamic parameters were obtained by the least square method combined with literature experiment results.The acquired thermodynamic parameters were used to calculate the isothermal sections of the ZrO_(2)−CaO−TiO_(2)system at 1473 and 1673 K.There existed a good agreement between experimental and predicted phase relationships,the experimental points which were inconsistent with calculated results may be attributed to experimental errors and the sluggish kinetics of cations for ZrO_(2)-based materials.In order to further verify the validity of the database,the thermodynamic parameters were also used to simulate the thermodynamic properties(specific heat capacity,enthalpy,and entropy)of CaZrTi_(2)O_(7) within 5%errors.Good consistency demonstrated that the present thermodynamic database was self-consistent and credible. 展开更多
关键词 ZrO_(2)−CaO−TiO_(2)system Gibbs free energy model CALPHAD method isothermal sections
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Free Energy Level Correction by Monte Carlo Resampling with Weighted Histogram Analysis Method
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作者 Seyoung Chung Sun Mi Choi +2 位作者 Wook Lee Kwang Hyun Cho Young Min Rhee 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第2期183-195,I0003,I0010-I0017,共22页
Free energy calculations may provide vital information for studying various chemical and biological processes.Quantum mechanical methods are required to accurately describe interaction energies,but their computations ... Free energy calculations may provide vital information for studying various chemical and biological processes.Quantum mechanical methods are required to accurately describe interaction energies,but their computations are often too demanding for conformational sampling.As a remedy,level correction schemes that allow calculating high level free energies based on conformations from lower level simulations have been developed.Here,we present a variation of a Monte Carlo(MC)resampling approach in relation to the weighted histogram analysis method(WHAM).We show that our scheme can generate free energy surfaces that can practically converge to the exact one with sufficient sampling,and that it treats cases with insufficient sampling in a more stable manner than the conventional WHAM-based level correction scheme.It can also provide a guide for checking the uncertainty of the levelcorrected surface and a well-defined criterion for deciding the extent of smoothing on the free energy surface for its visual improvement.We demonstrate these aspects by obtaining the free energy maps associated with the alanine dipeptide and proton transfer network of the KillerRed protein in explicit water,and exemplify that the MC resampled WHAM scheme can be a practical tool for producing free energy surfaces of realistic systems. 展开更多
关键词 Free energy level correction Weighted histogram analysis method Monte Carlo resampling
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尖晶石结构反转提高氧还原催化活性的密度泛函研究 被引量:3
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作者 杨娜 王俊 +5 位作者 吴光平 李莉 丁炜 齐学强 陈四国 魏子栋 《中国科学:化学》 CAS CSCD 北大核心 2017年第7期882-890,共9页
基于实验发现尖晶石型催化剂晶体结构的反转会使其对氧还原反应(ORR)的催化活性显著提高,本文通过密度泛函理论(DFT)计算方法探究了尖晶石(Co_3O_4)-反尖晶石(Co_2FeO_4)-尖晶石(CoFe_2O_4、Fe_3O_4)的结构反转对氧还原催化活性提高的本... 基于实验发现尖晶石型催化剂晶体结构的反转会使其对氧还原反应(ORR)的催化活性显著提高,本文通过密度泛函理论(DFT)计算方法探究了尖晶石(Co_3O_4)-反尖晶石(Co_2FeO_4)-尖晶石(CoFe_2O_4、Fe_3O_4)的结构反转对氧还原催化活性提高的本质.计算发现,随着尖晶石结构的反转,反尖晶石带隙收窄,导电性增强;费米能级按"尖晶石(Co_3O_4)>反尖晶石(Co_2FeO_4)>尖晶石(CoFe_2O_4、Fe_3O_4)"的次序依次降低,氧还原第一步电子转移能力逐渐变弱.此外,由于反尖晶石Co_2FeO_4八面体占位,Fe、Co原子间的异化效应使O–O键的活化程度最为显著.氧还原吉布斯自由能表明,若各催化剂电子传输能力相同,则反尖晶石Co_2FeO_4与尖晶石Co_3O_4较尖晶石CoFe_2O_4和Fe_3O_4更利于OH的脱附.综合分析表明,反尖晶石Co_2FeO_4平衡了掺杂前后尖晶石催化剂的导电性、第一步电子转移能力、对O_2的活化和OH的脱附能力,呈现出最优的ORR催化活性. 展开更多
关键词 尖晶石 氧还原反应 异化效应 密度泛函理论 吉布斯自由能图
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Effect of ketyl radical on the structure and performance of holographic polymer/liquid-crystal composites 被引量:3
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作者 Xiaoyu Zhao Shanshan Sun +5 位作者 Ye Zhao Rong-Zhen Liao Ming-De Li Yonggui Liao Haiyan Peng Xiaolin Xie 《Science China Materials》 SCIE EI CSCD 2019年第12期1921-1933,共13页
Holographic polymer/liquid-crystal composites,which are periodically ordered materials with alternative polymer-rich and liquid-crystal-rich phases, have drawn increasing interest due to their unique capabilities of r... Holographic polymer/liquid-crystal composites,which are periodically ordered materials with alternative polymer-rich and liquid-crystal-rich phases, have drawn increasing interest due to their unique capabilities of reconstructing colored three-dimensional(3 D) images and enabling the electro-optic response. They are formed via photopolymerization induced phase separation upon exposure to laser interference patterns, where a fast photopolymerization is required to facilitate the holographic patterning. Yet, the fast photopolymerization generally leads to depressed phase separation and it remains challenging to boost the holographic performance via kinetics control.Herein, we disclose that the ketyl radical inhibition is able to significantly boost the phase separation and holographic performance by preventing the proliferated diffusion of initiating radicals from the constructive to the destructive regions. Dramatically depressed phase separation is caused when converting the inhibiting ketyl radical to a new initiating radical, indicating the significance of ketyl radical inhibition when designing high performance holographic polymer composites. 展开更多
关键词 liquid crystal ordered structures PHOTOPOLYMERIZATION INHIBITION HOLOGRAPHY
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