著者
Michihisa KOYAMA Seiichiro KIMURA Yasunori KIKUCHI Takao NAKAGAKI Kenshi ITAOKA
出版者
公益社団法人 化学工学会
雑誌
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN (ISSN:00219592)
巻号頁・発行日
pp.13we345, (Released:2014-06-26)
被引用文献数
6 28

It has been an important target to realize a sustainable energy usage in the future, regardless of the country. Japan is now compelled to consider a new paradigm of energy policy due to the nuclear power plant failures after March 11, 2011. To discuss the ideal or a favorable future of Japan’s energy, understanding the present status as well as the available energy options in the future will be an initial step, followed by discussion of the issues related to each option. The aim of this article is to summarize the present status of Japan’s energy systems and to clarify the major points of discussions for the realization of future sustainable energy systems. In addition, the major options of both energy supply and demand sides are summarized. The issues for realizing the future energy systems are discussed from the large-scale penetration of renewable systems, the demand side energy management and savings, the mobility, and the centralized electricity grid viewpoints, to provide a common basis for the discussion of future energy systems in Japan.
著者
Tien Quang NGUYEN Yusuke NANBA Michihisa KOYAMA
出版者
Society of Computer Chemistry, Japan
雑誌
Journal of Computer Chemistry, Japan (ISSN:13471767)
巻号頁・発行日
vol.21, no.4, pp.111-117, 2022 (Released:2023-05-16)
参考文献数
24
被引用文献数
1

Thermodynamic properties and atomic configuration of PdRu alloy were investigated using Wang-Landau Monte Carlo method in combination with a newly-developed universal neural network potential. By using this new potential, excess energy of PdRu alloy was calculated. It is found that PdRu alloy in FCC lattice is unstable in the full range of alloy composition. This agrees with previous study based on density functional theory. The combined method was able to determine the configurational density of states, from which thermodynamic properties of the alloy were derived. It is found that when temperature increases, the excess free energy of the alloy is reduced, increasing the possibility of alloy mixing. Depending on the composition, transition peaks appear at finite temperatures where there are changes of preferable atomic arrangement due to the effect of temperature via the configurational entropy. In addition, the analyses on short-range order parameter and bond fraction show that PdRu alloy prefers to be in segregated form, where Pd and Ru are immiscible at low temperature, consistent with the experimental observations. The random mixing of Pd and Ru atoms in the form of solid-solution can occur at high temperature.