• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.112-114
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• 2009

Charge injection at electrode-organic interfaces is key to the performance, lifetime and stability of organic electronic devices. The link between fundamental material properties and the energy-level alignment at electrode-organic interfaces will be discussed. In addition the impact of the injection barrier height-a parameterization of the energylevel alignment-on device characteristics will also be discussed.

• Journal of Magnetics
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• v.7 no.4
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• pp.156-159
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• 2002

We have investigated the escape rate of nano-magnetic particle with a magnetic field applied along the easy axis. The model studied here is described by the Hamiltonian H=$K_1\hat{S}{_z^2}$ ＋ $K_2\hat{S}{_y^2}$ ＋ $g{\mu}_bB$ $\hat{S}_x(K_1>K_2>0)$ and the escape rate was calculated with in the semiclassical approximation. We have obtained a diagram for orders of the phase transition depending on the anisotropy constant and the external field. For $K_2$/$K_1>$0.85 the present model reveals the existence of the first order transition within the quantum regime.

• Bulletin of the Korean Mathematical Society
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• v.49 no.2
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• pp.435-443
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• 2012

The Yamabe invariant is a topological invariant of a smooth closed manifold, which contains information about possible scalar curvature on it. It is well-known that a product manifold $T^m{\times}B$ where $T^m$ is the m-dimensional torus, and B is a closed spin manifold with nonzero $\^{A}$-genus has zero Yamabe invariant. We generalize this to various T-structured manifolds, for example $T^m$-bundles over such B whose transition functions take values in Sp(m, $\mathbb{Z}$) (or Sp(m - 1, $\mathbb{Z}$) ${\oplus}\;{{\pm}1}$ for odd m).

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2711-2718
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• 2012

The alkylation of the ambident enolates of a methyl glycinate Schiff base with ethyl chloride was studied at B3LYP and MP2 levels with $6-31+G^*$ basis set. The free (E)-enolates and (Z)-enolate are similar in energy and geometry. The transition states for the alkylation of the free (E)/(Z)-enolate with ethyl chloride have similar energy barriers of ~13 kcal/mol. However, with a lithium ion, the (E)-enolate behaves as an ambident enolate and makes a cyclic lithium-complex in bidentate pattern which is more stable by 11-23 kcal/mol than the (Z)-enolate-lithium complexes. And the TS for the alkylation of (E)-enolate-lithium complex coordinated with one methyl ether is lower in energy than those from (Z)-enolate-lithium complexes by 4.3-7.3 kcal/mol. Further solvation model (SCRF-CPCM) and reaction coordinate (IRC) were studied. This theoretical study suggests that the alkylation of ambident enolates proceeds with stable cyclic bidentate complexes in the presence of metal ion and solvent.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3655-3657
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• 2014

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.25-29
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• 2001

Nucleophilic substitution reactions of O-imidomethyl derivatives of phenols with OH- were studied theoretically using the semiempirical AM1 and Solvation Model 2.1 (SM2.1) methods in the gas phase and aqueous solution, respectively. In the gas phase, the two reaction paths, in which the imide (1a) or phenol (1b) is functioning as a leaving group, can occur competitively. In contrast, in aqueous solution, path (1b) becomes more favorable than (1a) because the transition states (TS) of path (1b) are more stabilized by solvent. Differences in solvation energies are caused by the structural differences of TS, i.e., the TS via path (1b) is more dissociative than that via path (1a). Therefore we conclude that the solvent effects play an important role in the hydrolysis of O-imidomethyl derivatives of phenols. However, reactivity is dependent on the acidities of both the imide and the phenol fragments since the ρz values vary progressively from 4.2 (Z' = I) to 2.5 (Z' = IV) as the acidities of imide increase. These are in good agreement with the experimental results.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.342-342
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• 2003

• Bulletin of the Korean Mathematical Society
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• v.54 no.5
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• pp.1699-1718
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• 2017

We give a construction of the second Chern number of a vector bundle over a smooth projective surface by means of adelic transition matrices for the vector bundle. The construction does not use an algebraic K-theory and depends on the canonical ${\mathbb{Z}}-torsor$ of a locally linearly compact k-vector space. Analogs of certain auxiliary results for the case of an arithmetic surface are also discussed.

• Electrical & Electronic Materials
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• v.8 no.2
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• pp.190-195
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• 1995

Temperature dependences of the dielectric constant K(T), remanent polarization $P_{r}$, (T), effective birefringence overbar .DELTA.n(T), transmitted light intensity and quadratic electro optic coefficient R(T) of the two-stage sintered xBa(L $a_{1}$2/N $b_{1}$2/) $O_{3}$-(1-x)Pb(Z $r_{y}$ $Ti_{1-y}$) $O_{3}$(x=0.085, 0.09, 0.40.leq.y.leq.0.70) ceramics were investigated. Increasing the PbZr $O_{3}$ contents, the crystal structure of a specimen was changed from a tetragonal phase to a rhombohedral and cubic phase, and the phase transition was showed a diffuse phase transition(DPT) characteristics. In the compositions which located on the PE-FE phase boundary, the discrepancy was observed between the Curie temperature and temperature which a microscopic polarization and effective birefringence were disappeared.red.d.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.719-721
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• 2011