http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Geohegan, David B. (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
-
A hybrid optimization algorithm to explore atomic configurations of TiO<sub>2</sub> nanoparticles
Inclan, Eric,Geohegan, David,Yoon, Mina Elsevier 2018 Computational materials science Vol.141 No.-
<P><B>Abstract</B></P> <P>In this paper we present a hybrid algorithm comprised of differential evolution, coupled with the Broyden–Fletcher–Goldfarb–Shanno quasi-Newton optimization algorithm, for the purpose of identifying a broad range of (meta)stable Ti<I> <SUB>n</SUB> </I>O<SUB>2</SUB> <I> <SUB>n</SUB> </I> nanoparticles, asan example system, described by Buckingham interatomic potential. The potential and its gradient are modified to be piece-wise continuous to enable use of these continuous-domain, unconstrained algorithms, thereby improving compatibility. To measure computational effectiveness a regression on known structures is used. This approach defines effectiveness as the ability of an algorithm to produce a set of structures whose energy distribution follows the regression as the number of Ti<I> <SUB>n</SUB> </I>O<SUB>2</SUB> <I> <SUB>n</SUB> </I> increases such that the shape of the distribution is consistent with the algorithm’s stated goals. Our calculation demonstrates that the hybrid algorithm finds global minimum configurations more effectively than the differential evolution algorithms, widely employed in the field of materials science. Specifically, the hybrid algorithm is shown to reproduce the global minimum energy structures reported in the literature up to <I>n</I> =5, and retains good agreement with the regression up to <I>n</I> =25. For 25< <I>n</I> <100, where literature structures are unavailable, the hybrid effectively obtains structures that are in lower energies per TiO<SUB>2</SUB> unit as the system size increases.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
-
Edge-Controlled Growth and Etching of Two-Dimensional GaSe Monolayers
Li, Xufan,Dong, Jichen,Idrobo, Juan C.,Puretzky, Alexander A.,Rouleau, Christopher M.,Geohegan, David B.,Ding, Feng,Xiao, Kai American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.1
<P>Understanding the atomistic mechanisms governing the growth of two-dimensional (2D) materials is of great importance in guiding the synthesis of wafer-sized, single-crystalline, high-quality 2D crystals and heterostructures. Etching, in many cases regarded as the reverse process of material growth, has been used to study the growth kinetics of graphene. In this work, we explore a growth-etching-regrowth process of monolayer GaSe crystals, including single-crystalline triangles and irregularly shaped domains formed by merged triangles. We show that the etching begins at a slow rate, creating triangular, truncated triangular, or hexagonally shaped holes that eventually evolve to exclusively triangles that are rotated 60 degrees with respect to the crystalline orientation of the monolayer triangular crystals. The regrowth occurs much faster than etching, reversibly filling the etched holes and then enlarging the size of the monolayer crystals. A theoretical model developed based on kinetic Wulff construction (KWC) theory and density functional theory (DFT) calculations accurately describe the observed morphology evolution of the monolayer GaSe crystals and etched holes during the growth and etching processes, showing that they are governed by the probability of atom attachment/detachment to/from different types of edges with different formation energies of nucleus/dents mediated by chemical potential difference Ait between Ga and Se. Our growth-etching-regrowth study provides not only guidance to understand the growth mechanisms of 2D binary crystals but also a potential method for the synthesis of large, shape-controllable, high-quality single-crystalline 2D crystals and their lateral heterostructures.</P>
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
