• Title/Summary/Keyword: single-atom

Search Result 193, Processing Time 0.039 seconds

Syntheses, Structures, and Characterization of Two Novel Copper(II) and Cadmium(II) Compounds Based on Pyridyl Conjugated 1,2,3-Triazole

  • Hong, Jin-Long;Qu, Zhi-Rong;Ma, Hua-Jun;Wang, Gai-Gai;Zhao, Hong
    • Bulletin of the Korean Chemical Society
    • /
    • v.35 no.5
    • /
    • pp.1495-1500
    • /
    • 2014
  • Two new complexes with 5-methyl-1-(pyridine-3-yl)-1H-1,2,3-triazole-4-carboxylic acid (Hmptc) ligand: [$Cd(mptc)_2(H_2O)_4$] (1) and $[Cu(mptc)_4{\cdot}2H_2O]_n$ (2) were prepared and their crystal structures were determined by single crystal X-ray diffraction analyses. In complex 1, the Cd(II) ions coordinates with the pyridyl nitogen atom from the Hmptc ligand, forming a mononuclear Cd(II) compound. Complex 2 exhibits a novel two-dimensional (2D) polymer in which four Hmptc ligands stabilize the Cu(II) atom. And the coordination involves one nitrogen atom of the triazole, one oxygen atom of the carboxylic acid and the pyridyl nitrogen atom. In addition, FT-IR and solid-state fluorescent emission spectroscopy of two compounds have been determined.

Refinement of protein NMR structures using atomistic force field and implicit solvent model: Comparison of the accuracies of NMR structures with Rosetta refinement

  • Jee, Jun-Goo
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.26 no.1
    • /
    • pp.1-9
    • /
    • 2022
  • There are two distinct approaches to improving the quality of protein NMR structures during refinement: all-atom force fields and accumulated knowledge-assisted methods that include Rosetta. Mao et al. reported that, for 40 proteins, Rosetta increased the accuracies of their NMR-determined structures with respect to the X-ray crystal structures (Mao et al., J. Am. Chem. Soc. 136, 1893 (2014)). In this study, we calculated 32 structures of those studied by Mao et al. using all-atom force field and implicit solvent model, and we compared the results with those obtained from Rosetta. For a single protein, using only the experimental NOE-derived distances and backbone torsion angle restraints, 20 of the lowest energy structures were extracted as an ensemble from 100 generated structures. Restrained simulated annealing by molecular dynamics simulation searched conformational spaces with a total time step of 1-ns. The use of GPU-accelerated AMBER code allowed the calculations to be completed in hours using a single GPU computer-even for proteins larger than 20 kDa. Remarkably, statistical analyses indicated that the structures determined in this way showed overall higher accuracies to their X-ray structures compared to those refined by Rosetta (p-value < 0.01). Our data demonstrate the capability of sophisticated atomistic force fields in refining NMR structures, particularly when they are coupled with the latest GPU-based calculations. The straightforwardness of the protocol allows its use to be extended to all NMR structures.

Atomistic Study of Metal Cluster Deposition and Nanowires (금속 덩어리 증착 및 금속 나노와이어에 관한 원자단위 이론 연구)

  • 강정원;이강환;황호정
    • Proceedings of the IEEK Conference
    • /
    • 2001.06b
    • /
    • pp.21-24
    • /
    • 2001
  • We studied aluminum cluster deposition using molecular dynamics simulation. We investigated the variations of the cluster momentum and the impulse force during collisions, and found that the close-packed cluster impact has some of properties of the single particle collision and the linear chain collisions. We also simulated the series of energetic cluster deposition with energy Per atom. When energy Per atom in cluster has some eV rather than very low, the intermixing occurred easily in growth film and we can obtain a good film without subsequent annealing process.

  • PDF

Mode of Occurrence and Compositional Variation of Electrum from the Dunjeon and Baegjeon Gold Deposits (둔전(屯田) 및 백전광상(栢田鑛床)에서 산출(産出)되는 에렉트럼의 산출상태(産出狀態)와 조성변화(組成變化))

  • Lee, Chan Hee;Park, Hee-In
    • Journal of the Mineralogical Society of Korea
    • /
    • v.6 no.2
    • /
    • pp.94-104
    • /
    • 1993
  • The compositional variation of electrums from gold-silver and antimony deposits in the Dunjeon Baegjeon mining area, range from 22.6 to 69.5 atom% of Ag. Ag contents in electrums vary with paragenetic sequences and associated minerals. Ag contents increase from core to margin in a single grain. Compositional range of electrums from the North ore deposits of the Dunjeon gold mine are from 22.6 to 29.5 atom% of Ag. Electrums contain Cu(0.40 to 0.55 atom%) and Bi(0.35 to 0.67 atom%). Composition of electrums from the South ore deposits of the Dunjeon gold mine vasies from 33.6 to 69.5 atom% of Ag. Cu and As contents in electrums range from 0.20 to 1.92 and from 0.70 to 1.90 atom%, respectively. As the content of Ag in electrums increase, the contents of Bi and As in electrums increase but that of Cu decrease. Electrums of the Baegjeon gold deposits contain 35.6 to 63.5 atom% of Ag, suggesting that Au contents in electrums associated with base metal sulfied be higher than those associate with Ag-minerals. Ag/Au rations in electrums increase with decreasing temperature, salinity and $fs_2$ of the mineralizing solution.

  • PDF

Molecular Dynamics Study of the Energetic Aluminum Cluster Impact and Deposition (운동에너지를 가지는 알루미늄 덩어리 충돌 및 증착에 관한 분자동력학 연구)

  • 강정원;황호정
    • Journal of the Korean Vacuum Society
    • /
    • v.10 no.3
    • /
    • pp.283-288
    • /
    • 2001
  • We have investigated aluminum cluster deposition using a classical molecular dynamics simulations. We studied the variations of the cluster momentum and the impulse force during collisions, and found that the close-packed cluster impact has some of properties of the single particle collision and the linear atomic chain collisions. We also simulated the series of energetic cluster deposition with energy Per atom. When energy Per atom in cluster has some eV rather than very low, the intermixing occurred easily in growth film and we can obtain a good film without subsequent annealing process.

  • PDF

Equivalent Continuum Model for the Single Wall Carbon Nanotube (Single Wall Carbon Nanotube의 등가 연속체 모델에 대한 연구)

  • 김병구;전흥재
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2003.04a
    • /
    • pp.227-234
    • /
    • 2003
  • In this study, an equivalent continuum model for single wall carbon nanotube is proposed. The model links interatomic potentials and atom structure of a materials to a constitutive model on the continuum level. The Young's modulus and shear modulus were predicted by the model. The predictions were in good agreement with the prior experimental results available in the literatures. Also, the strain energy of the carbon nanotube was predicted as a function of the radius of the carbon nanotube.

  • PDF