A molecular dynamics simulation study was performed to investigate the formation and evolution mechanisms of nano-clusters during the rapid solidification of liquid CaToMg30 alloy. The cluster-type index method （CTIM...A molecular dynamics simulation study was performed to investigate the formation and evolution mechanisms of nano-clusters during the rapid solidification of liquid CaToMg30 alloy. The cluster-type index method （CTIM） was adopted to describe microstructure evolutions of nano-clusters during solidification. Results indicate that amorphous structure is mainly formed with three bond-types of 1551, 1541 and 1431 at the cooling rate of 5~1011 K/S, and glass transition temperature Tg is about 530 K; the icosahedron cluster of （12 0 12 0） plays a key role in formation of amorphous structure, and smaller Mg atoms are much more probable to be central atoms of icosahedron clusters; and nano-clusters are mainly formed by combining medium-size clusters. Interestingly, it was also found that formation and evolution processes of the nano-cluster display a three-stage feature which is analogous to crystallization process of amorphous alloy.展开更多
In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH...In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH and NaBH4 should be added drop-wise to the solution of Au （III） at the same time. The formula and molecular purity of [Au25（SePh）ls] TOA＋ clusters are characterized by MALDI-TOF mass spectrometry, NMR and TGA analysis. Furthermore, some critical parameters to obtain pure [Au25（SePh）18]-TOA＋ are identified, including the NaBH4-to-Au ratio, the selenolate-to-Au ratio and the temperature. The facile, direct, high yield synthetic method can be widely applied in the theoretical research of Au clusters protected by selenol.展开更多
基金supported by the National High Technology Research and Development Program of China(2015AA020502)the National Key Research and Development Program of China(2017YFA0205300)the National Natural Science Foundation of China(81325011,21175020)~~
基金Project(50831003) supported by the National Natural Science Foundation of ChinaProject(20114BAB215026) supported by Jiangxi Provincial Natural Science Foundation,ChinaProject(ZD201002) supported by Fund for Basic Scientific Research of Gannan Medical University,China
文摘A molecular dynamics simulation study was performed to investigate the formation and evolution mechanisms of nano-clusters during the rapid solidification of liquid CaToMg30 alloy. The cluster-type index method （CTIM） was adopted to describe microstructure evolutions of nano-clusters during solidification. Results indicate that amorphous structure is mainly formed with three bond-types of 1551, 1541 and 1431 at the cooling rate of 5~1011 K/S, and glass transition temperature Tg is about 530 K; the icosahedron cluster of （12 0 12 0） plays a key role in formation of amorphous structure, and smaller Mg atoms are much more probable to be central atoms of icosahedron clusters; and nano-clusters are mainly formed by combining medium-size clusters. Interestingly, it was also found that formation and evolution processes of the nano-cluster display a three-stage feature which is analogous to crystallization process of amorphous alloy.
基金the financial support by the National Natural Science Foundation of China (20871112, 21072001, 21372006)Changjiang Scholars Program+1 种基金the Scientific Research Foundation for Returning Overseas Chinese Scholars, State Education Ministry, Ministry of Human Resources and Social Security, Anhui Province International Scientific and Technological Cooperation Project211 Project of Anhui University
文摘In this article, we present a facile, direct, synthetic approach of preparing monodisperse [Au2s（SePh）ls]- nanoclusters in high yield. In this synthetic approach, two-phase Brust-Schiffrin method is used. Both PhSeH and NaBH4 should be added drop-wise to the solution of Au （III） at the same time. The formula and molecular purity of [Au25（SePh）ls] TOA＋ clusters are characterized by MALDI-TOF mass spectrometry, NMR and TGA analysis. Furthermore, some critical parameters to obtain pure [Au25（SePh）18]-TOA＋ are identified, including the NaBH4-to-Au ratio, the selenolate-to-Au ratio and the temperature. The facile, direct, high yield synthetic method can be widely applied in the theoretical research of Au clusters protected by selenol.
