• 제목/요약/키워드: D.B.H. analysis

검색결과 1,378건 처리시간 0.035초

Full Geometry Optimizations of Bond-Stretch Isomers of C202+ Fullerene Dication by the Hybrid Density Functional B3LYP Methods

  • Lee, Ji-Hyun;Lee, Chang-Hoon;Park, Sung-S.;Lee, Kee-Hag
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.277-280
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    • 2011

  • We studied the relative stability and atomic structure of five $C_{20}^{2+}$ isomers obtained by two-electron ionization of a $C_{20}$ cage (the smallest fullerene). All the isomers are bond-stretch isomers, i.e., they differ in bond length. In particular, in one of the isomers with Ih symmetry, all the bond lengths are equal. Full geometry optimizations of the dipositive ion $C_{20}^{2+}$ were performed using the hybrid density functional (B3LYP/6-31G(d)) methods. All isomers were found to be true minima by frequency analysis at the level of B3LYP/6-31G(d) under the reinforced tight convergence criterion and a pruned (99,590) grid. The zero-point correction energy for the cage bond-stretch isomers was in the increasing order $D_{2h}<C_{2h}<C_2<T_h<I_h$ of $C_{20}^{2+}$. The energy difference among the isomers of cage dipositive ions was less than that among neutral cage isomers. Our results suggest that these isomers show bond-stretch isomerism and that they have an identical spin state and an identical potential energy curve. Although the predominant electronic configurations of the isomers are similar, the frontier orbital characteristics are different, implying that we could anticipate an entirely different set of characteristic chemical reactions for each type of HOMO and LUMO.

  • https://doi.org/10.5012/bkcs.2011.32.1.277 인용 PDF KSCI

고전압 차단기용 솔레노이드 액추에이터의 거동 (Behavior of the Solenoid Actuator for High-Voltage Circuit Breaker)

  • 윤소남;함영복;안병규;김고도
    • 유공압시스템학회논문집
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    • 제1권3호
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    • pp.1-6
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    • 2004

  • In the last few years, a considerable number of studies have been made on On-Off solenoid for fluid control. But, only few attempts have so far been made at solenoid actuator for high-voltage circuit breaker. In case of the high-pressure and high-flow system like high-voltage circuit breaker, a big size of On/Off solenoid is necessary which size is proportional to control pressure and flow rate. So, it is non-effective in the view point of system optimization. In this paper, On/Off solenoid actuator with the farce amplifier connected to the solenoid rod was proposed to get a high mechanical force and a fast response time. The magnetic force and the mechanical stress distributions were analysed using finite element analysis. The performances of suggested solenoid actuator were evaluated through the experimental results and compared with the analysis results.

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A high precision shear flexible element for bending analysis of thick/thin triangular plate

  • Haldar, S.;Das, P.;Manna, M.C.
    • Structural Engineering and Mechanics
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    • 제18권1호
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    • pp.79-90
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    • 2004

  • A high precision shear deformable triangular element has been proposed for bending analysis of triangular plate. The element has twelve nodes at the three sides and four nodes inside the element. Initially the element has thirty-five degrees of freedom, which has been reduced to thirty by eliminating the degrees of freedom of the internal nodes through static condensation. Plates having different boundary conditions, side ratios (b/a) and thickness ratios (h/a = 0.001, 0.1 and 0.2) have been analyzed using the proposed shear locking free element. Concentrated and uniformly distributed transverse loads have been used for the analysis. The formulation is made based on first order shear deformation theory. For validation of the present element and formulation few results of thin triangular plate have been compared with the analytical solutions. Results for thick plate have been presented as new results.

  • https://doi.org/10.12989/sem.2004.18.1.079 인용 KSCI