Subjects: Computer Science >> Other Disciplines of Computer Science Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2022-08-15
Abstract： With the development of high-performance computing architectures, many software and hardware have a multi-layer parallel structure. A large amount of allocation schemes can be involved when users allocate multi-layered system resources to many computational tasks distributed in different vertical tiers and horizontal groupings. It is becoming increasingly difficult for users to determine the optimal parallel parameters and hardware resource usage. We investigate an optimization method which is helpful for users to automate the determination of the optimal application parallel parameters and hardware usage for high-efficient and/or large-scale computation. In addition, we propose a solution that deeply integrates the optimization method with the job scheduling system, which has produced excellent practical results.
Peer Review Status:
Awaiting Review
Subjects: Materials Science >> Materials Science (General) submitted time 2022-06-20
Li, Xiangyan
Li, Xiaolin
Zhang, Yange
Xu, Yichun
Wu, Xuebang
Xie, Zhuoming
Wang, Xianping
Pan, Bicai
Liu, Changsong
Fang, Qianfeng
Chen, Junling
Luo, Guangnan
Wang, Zhiguang
Abstract：
The behavior of nano-voids composed of vacancies (Vs) at grain boundaries (GBs) is fundamental to the design of the radiation tolerance of poly-crystalline metals (PCs) via GB engineering. In this study, based on differential evolution, a framework for determining the stable structure of GB nano-voids is developed. Combining the framework with multiscale simulations, we elucidate the vacancy-accumulation and GB void
formation mechanism under irradiation. A GB-structure dependent picture is revealed. At special coincidence-site-lattice (CSL) GBs of Ʃ5(310) and Ʃ5(210) with a medium V-GB binding energy, the V could be reemitted from the GB and also has driving force to be clustered at the GB, developing particularly stable V-clusters from a linear configuration to a platelet and finally to three-dimensional void that has large strain fields in iron with small bulk modulus and a bulk-void alike structure in the GB with large bulk modulus. A group of vacancies reconstruct their positions during the growth. The ripening is also mediated by the mobility of small V-clusters in addition to free Vs. General high-angle and low-angle GBs trap Vs efficiently, where V-clusters only align one-dimensionally or hardly nucleate. Based on the bonding among the vacancies and their neighboring atoms of a nano-void, we propose a high-accuracy predictive linear energetic model applied to the nano-void both at the iron/molybdenum/tungsten GBs and in the grain interior. The model captures the anisotropic feature of a nano-void and reproduces the oscillated vacancy energy level near a nano-void, showing distinct advantages over conventional continuum model and Wulff construction based energy model. Finally, the collective behavior of multiple GBs plays a role in the GB void formation. The present work offers fundamental mechanistic insights to GB nano-void formation and growth and sets a key step towards GB-void prevention in PCs by reducing the fraction of special CSL-GBs.
Peer Review Status:Awaiting Review
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