• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.354-354
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• 2010

Supramolecualr ordering has been actively studied due to it's possible applications to the fabrication processes of nano-electronic devices. Van der Waals interaction and hydrogen bonding are frequently studied mechanisms for various molecular structures based on non-uniform charge distributions. Halogen atoms in molecules can have electrostatic interactions with similar strength. Big halogen atoms have strong non-uniform charge distributions. To study molecular orderings formed by hydrogen and halogen interactions, we chose a molecular system containing oxygen, hydrogen, and bromine atoms, a bromo-quinone. A two-dimensional molecular network was studied on Au(111) using a low-temperature scanning tunneling microscope. Bromo-quinone molecules form self-assembled square grids having windmill structures. Their molecular orderings, chiral structures, and defects are explained in terms of hydrogen and halogen interactions.

• Bulletin of the Korean Chemical Society
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• 제18권9호
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• pp.1002-1006
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• 1997

1H NMR spectra of D2O solutions containing 2,2-dimethylaziridine (1) or 2-methylaziridine (2) and [SiW11COⅡO39]6- (SiW11Co) or [SiW11NiⅡO39]6- (SiW11Ni) exhibit separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. Identified are two linkage isomers with the methyl group of 2 at trans or cis position with respect to the metal. The isotropic shifts of 1 and 2 coordinated to SiW11Ni originate mainly from the contact shifts, and they agree reasonably with the relative values reported for similar ligands coordinated to bis(2,4-pentanedionato)nickel(Ⅱ). The isotropic shifts for the SiW11Co complexes were separated into contact and pseudocontact contributions. The pseudocontact shifts show that (χ∥-χ⊥) is positive, while that for the SiW11Co complexes of pyridine derivatives is negative. This result indicates that the ordering of dxy and dxz, dyz orbitals in SiW11Co complexes can be reversed by ligands.

• 대한수학회보
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• 제56권3호
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• pp.569-583
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• 2019

Given a graph G, the Motzkin and Straus formulation of the maximum clique problem is the quadratic program (QP) formed from the adjacent matrix of the graph G over the standard simplex. It is well-known that the global optimum value of this QP (called Lagrangian) corresponds to the clique number of a graph. It is useful in practice if similar results hold for hypergraphs. In this paper, we attempt to explore the relationship between the Lagrangian of a hypergraph and the order of its maximum cliques when the number of edges is in a certain range. Specifically, we obtain upper bounds for the Lagrangian of a hypergraph when the number of edges is in a certain range. These results further support a conjecture introduced by Y. Peng and C. Zhao (2012) and extend a result of J. Talbot (2002). We also establish an upper bound of the clique number in terms of Lagrangians for hypergraphs.

• Bulletin of the Korean Chemical Society
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• 제19권9호
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• pp.934-942
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• 1998

$^13CO$ chemisorbed on platinum particles in L-zeolite has been investigated by static and magic angle spinning NMR spectroscopy. The representative spectra are composed of a broad asymmetric peak with a center of gravity at 230±30 ppm and a sharp symmetric peak at 124±2 ppm which is tentatively assigned to physisorbed $CO_2$, on inner walls of L-zeolite. Overall, the broad resonance component is similar to our previous results of highly dispersed (80-96%) CO/Pt/silica or CO/Pt/alumina samples, still showing metallic characters. The principal difference is in the first moment value. The broad peak in the spectra is assigned to CO linearly bound to Pt particles in the L-zeolites, and indicates a distribution of isotropic shifts from bonding site to bonding site. The NMR results reported here manifest that the Pt particles inside of the L-zeolites channels are not collectively the same with the ones supported on silica or alumina with similar dispersion in terms of Pt particle shape and/or ordering of Pt atoms in a particle. As a result, Pt particles of CO/Pt/L-zeolite were agglomerated accompanying CO desorption upon annealing. There were no definite changes in the NMR spectra due to differences of exchanged cations. Comparison of our observation on CO/Pt/L-zeolite with Sharma et al.'s reveals that even when the first moment, the linewidtb, and the relaxation times of the static spectra and the dispersion measured by chemisorption are similar, the properties of Pt particles can be dramatically different. Therefore, it is essential to take advantage of the strengths of several techniques together in order to interpret data reliably, especially for the highly dispersed samples.

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.723-727
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• 2003

Recently the ab initio effective valence shell Hamiltonian method $H^v$ has been extended to treat spin-orbit coupling in atoms or molecules. The quasidegenerate many-body perturbation theory based $H^v$ method has an advantage of determining the spin-orbit coupling energies of all valence states for both the neutral species and its ions with a similar accuracy from a single computation of the effective spin-orbit coupling operator. The new spin-orbit $H^v$ method is applied to calculating the fine structure splittings of the valence states of SiH, $SiH^+$, and $SiH^{2+}$ not only to assess the accuracy of the method but also to investigate the spin-orbit interaction of highly excited states of SiH species. The computed spin-orbit splittings for ground states are in good agreement with experiment and the few available ab initio computations. The ordering of fine structure levels of the bound and quasi-bound spin-orbit coupled valence states of SiH and its ions, for which neither experiment nor theory is available, is predicted.

• Macromolecular Research
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• 제14권2호
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• pp.155-165
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• 2006

The present article describes the experimental and theoretical observations on the formation of holographic, polymer-dispersed, liquid crystals and electrically switchable, photonic crystals. A phase diagram of the starting mixture of nematic liquid crystal and photo-reactive triacrylate monomer was established by means of differential scanning calorimetry (DSC) and cloud point measurement. Photolithographic patterns were imprinted on the starting mixture of LC/triacrylate via multi-beam interference. A similar study was extended to a dendrimer/photocurative mixture as well as to a single component system (tetra-acrylate). Theoretical modeling and numerical simulation were carried out based on the combination of Flory-Huggins free energy of mixing and Maier-Saupe free energy of nematic ordering. The combined free energy densities were incorporated into the time-dependent Ginzburg-Landau (Model C) equations coupled with the photopolymerization rate equation to elucidate the spatio-temporal structure growth. The 2-D photonic structures thus simulated were consistent with the experimental observations. Furthermore, 3-D simulation was performed to guide the fabrication of assorted photonic crystals under various beam-geometries. Electro-optical performance such as diffraction efficiency was evaluated during the pattern photopolymerization process and also as a function of driving voltage.

• 한국생활과학회지
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• 제15권3호
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• pp.439-447
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• 2006

The purpose of this study is to explore the accuracy and reliability of subjective evaluation instruments in evaluating sensibility of similar fabrics, Kendall's coefficient of concordance W (agreement among subjects) and Spearman rank correlation coefficient (reproducibility after 1 week) were used to evaluate which one is more efficient. Eight kinds of linen-like silk fabrics finished with polyurethane resin were used, Subjective evaluation instruments such as rating scale method, contrasting method against a control, rank ordering method, paired comparison and Quad analysis were used, 'Stiffness and Pliability' and 'Preference of summer fabric' were estimated, From the result of subjective stiffness and pliability, which are effective on objective properties of fabric, the rating scale method in Kendall's coefficient of concordance W and Quad analysis in Spearman rank correlation coefficient were given the highest score, From the result of subjective preference of summer fabric, which are effective on individual sensibility, contrasting method against a control in Kendall's coefficient of concordance W and Quad analysis in Spearman rank correlation coefficient revealed the highest score, Regarding the accuracy, reliability and efficiency, Quad analysis was an efficient method for subjective evaluation of linen-like silk fabrics.

• 서비스연구
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• 제7권3호
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• pp.21-36
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• 2017

최근 정보화 사업이 대형화, 지능화, 융합화되고 있지만 이를 관리 및 감독하는 정보시스템 감리 제도와 사업관리(PMO) 제도는 업무 범위가 중복되거나 경계가 명확하지 않은 부분이 많아 발주기관의 용역 선정에 어려움이 발생하고 있다. 독립성, 품질성, 경제성, 책임성이 개선된 사업관리 및 감리 프레임워크가 요구되며, 이에 따라 정보시스템 감리협회에서는 대략적인 프로세스가 구조화된 정보화 사업 종합관리 프레임워크를 제안하여 사업관리 및 감리 제도를 발전적으로 개편하려는 움직임을 보인다. 본 논문에서는 사업 초기의 발주활동에서부터 사후단계인 운영활동까지 전 단계에 걸친 정보화 사업 종합관리 프레임워크를 소개하고 기존의 관리제도와의 비교분석을 통해 업무 범위를 확인한다. 또한 기존제도와 유사제도를 분석해 감리제도와 PMO 제도 통합의 당위성을 살펴본다. 최종적으로 BSC 성과관리 지표를 기반으로 구현된 COBIT5의 IT 목표 틀을 평가도구로 활용해 종합관리 프레임워크의 적정성을 분석한다. 분석 결과는 정보화 사업의 담당자들이 종합관리 프레임워크의 실무적인 적용에 앞서 그 특성을 이해하는 데 도움이 될 것으로 기대한다.

• 한국산학기술학회논문지
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• 제15권12호
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• pp.7364-7371
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• 2014

건설공사 사후평가는 공공건설사업 수행성과를 평가하고 차후 유사사업 추진 시 이를 활용하여 공공건설사업 효율화에 기여하기 위한 제도이다. 건설공사를 계획하는 과정과 공사완료 후의 공사비, 공사기간, 수요, 효과 등에 대한 예측치와 실제치를 종합적으로 분석, 평가하여 시행의 효율성을 도모하는데 목적이 있다. 이를 통해 방만한 사업추진을 방지하고, 유사 건설공사의 품질 및 효율성 향상을 위한 자료로 활용하고 있다. 하지만, 건설공사 사후평가 자료를 유사 건설사업에 참조 및 활용하기 위해서는 건설공사 사후평가 결과정보에 대한 체계적인 관리가 필요하다. 따라서 본 연구는 발주청별로 실시하고 있는 건설공사 사후평가의 결과정보를 체계적으로 통합 관리하고, 활용할 수 있도록 국토교통부에서 고시한 건설공사 사후평가 시행지침을 기초로 하여 건설공사 사후평가시스템을 구축하였다. 이를 통해 공공 건설사업의 수행 시 유사 건설사업의 수요 증감, B/C 비율 등 결과정보의 참조 활용을 통해 품질 향상 및 효율적인 사업 추진이 가능한 기반을 마련하였으며, 향후 사후평가 결과정보의 체계적인 관리를 통해 종합적인 분석 및 평가 등 유용한 도구로 활용될 수 있으리라 기대된다.

• Journal of the Korean Data and Information Science Society
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• 제26권4호
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• pp.857-864
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• 2015

데이터 마이닝은 다양한 형태의 방대한 데이터 집합으로부터 보이지 않는 지식이나 새로운 법칙을 발견한 후, 이를 바탕으로 의사결정 등을 위한 정보로 활용하고자 하는 것이다. 데이터 마이닝 기법중의 하나인 군집 분석은 거리 또는 유사성 측도를 이용하여 집단을 분류하고, 구분된 각 집단의 특성을 파악하기 위한 기법이다. 본 논문에서는 주변 확률이 일부 포함된 확률적 흥미도 측도 기반의 유사성 측도들인 Peirce I, Peirce II, Cole I, Cole II, 그리고 이들을 응용한 Park I 및 Park II에 대한 대소 관계를 수식의 증명뿐만 아니라 예제 데이터에 의해서도 규명하였다. 그 결과, Cole I과 Cole II의 측도를 동시에 고려한 Loevinger 측도가 기존의 측도들 중에서는 상한이 되나 Park I 및 Park II를 함께 고려했을 경우에는 동시발생비율, 동시 비발생비율, 그리고 두 가지 형태의 불일치비율의 크기에 따라 변한다는 사실을 확인하였다.