月別: 2020年4月

[Published online Journal of Computer Chemistry, Japan Vol.18, 259-262, by J-STAGE]
<Title:> A Molecular Dynamics Study on Alumina/Carbon Nanotube Composite: How Does Annealing Affect Mechanical Properties?
<Author(s):> Yixin SU, Jing ZHANG, Qian CHEN, Yang WANG, Narumasa MIYAZAKI, Yusuke OOTANI, Nobuki OZAWA, Momoji KUBO
<Corresponding author E-Mill:> momoji(at)imr.tohoku.ac.jp
<Abstract:> Carbon nanotube (CNT) is conventionally expected to reinforce ceramic matrix like alumina. Previous experiments show that processing conditions such as annealing have positive effect on mechanical properties of the alumina/CNT composite. However, the reinforcing mechanism by annealing is not fully understood yet. For further improving the performance of alumina/CNT composite, this study aims to understand the reinforcing mechanism by annealing from the atomic scale with reactive molecular dynamics simulations. We conduct tensile simulations on pure alumina, non-annealed and annealed alumina/CNT composites, and then analyze the mechanical properties of the three models. Consequently, we find out that annealing enhances the interfacial interactions between alumina and CNT and reduces the interfacial slippage, so that the annealed CNT is more stretched than the non-annealed CNT, finally resulting in an improvement of the mechanical performance of composite.
<Keywords:> Carbon nanotubes, Ceramic matrix composites, Elastic properties, Reactive molecular dynamics simulations
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/5/18_2020-0001/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.18, 257-258, by J-STAGE]
<Title:> Conversion Reaction of Polyoxometalates from Anderson Structure to Keggin Structure
<Author(s):> Teruyoshi YAMAKAWA, Kazuo EDA, Toshiyuki OSAKAI, Takahito NAKAJIMA
<Corresponding author E-Mill:> 181s225s(at)stu.kobe-u.ac.jp
<Abstract:> Aiming at developing synthetic methods of new Keggin-type polyoxometalates (POMs) that can mediate proton-conjugated multi-electron transfer reactions useful for efficient regeneration of fuels, we have investigated the reaction routes from Anderson-type POMs to Keggin-type POMs. The POM systems with various kinds of heteroatoms as their central cations were calculated using the Nudged Elastic Band (NEB) method as well as the first-principles electronic structure method. The effects of the heteroatoms on the reaction routes have been discussed.
<Keywords:> Polyoxometalates, Polyoxotungstates, NEB
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/5/18_2019-0039/_article/-char/ja/

[Published online Journal of Computer Chemistry, Japan Vol.18, 254-256, by J-STAGE]
<Title:> アントラセン-ウレア誘導体の励起状態プロトン移動における蛍光挙動に関する解析
<Author(s):> 小野澤　周, 松井　亨, 西村　賢宣,, 守橋　健二
<Corresponding author E-Mill:> matsui(at)chem.tsukuba.ac.jp
<Abstract:> We investigated the hydrogen bonding interaction between the anion and nitrogen atom of the urea derivative nPUA (n = 1, 2, 9, where n is the substituted position of the parent anthracene) to examine a proton transfer reaction in the complex in the excited state, which is known as excited-state intermolecular proton transfer (ESPT). We revealed the details of the hydrogen bonding interaction between an anthracene-urea derivative and an acetate anion in the excited state by taking advantage of TD-DFT calculation.
<Keywords:> Density functional theory, Excited state, Proton transfer, Fluorescence, Molecular orbitals
<URL:> https://www.jstage.jst.go.jp/article/jccj/18/5/18_2019-0050/_article/-char/ja/