• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.3
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• pp.137-145
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• 2014

We present a design sensitivity analysis(DSA) method for multiscale problems based on bridging scale decomposition. In this paper, we utilize a bridging scale method for the coupled system analysis. Since the analysis of full MD systems requires huge amount of computational costs, a coupled system of MD-level and continuum-level simulation is usually preferred. The information exchange between the MD and continuum levels is taken place at the MD-continuum boundary. In the bridging scale method, a generalized Langevin equation(GLE) is introduced for the reduced MD system and the GLE force using a time history kernel is applied at the boundary atoms in the MD system. Therefore, we can separately analyze the MD and continuum level simulations, which can accelerate the computing process. Once the simulation of coupled problems is successful, the need for the DSA is naturally arising for the optimization of macro-scale design, where the macro scale performance of the system is maximized considering the micro scale effects. The finite difference sensitivity is impractical for the gradient based optimization of large scale problems due to the restriction of computing costs but the analytical sensitivity for the coupled system is always accurate. In this study, we derive the analytical design sensitivity to verify the accuracy and applicability to the design optimization of the coupled system.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.172-179
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• 2010

The study on works motivated from interest in the nature of matters and inherent visual-perceptual structure in them aims at expressing formative continuity of the connections of three dimensions of simple geometrical shapes such as circles and lines, which are characteristics of shape of molecules. With such a purpose, this study examined the geometrical shapes in modern arts and structural connection and symbolism of molecule structure, and based on such considerations, it expressed successive formative beauty which comes from repetitive connection between units by creating stereogram of simple geometrical shapes of molecule structure. The types of works include a method of connecting the units of molecule models and molecules seen in electron microscope with lines as a parameter and connecting units directly, which are used to express body accessory and metallic sculptures. Consequently, it attempted formation occurring spatial composition of continuity of division and duplication through direct connection between units and circular continuity coming from connection of simple geometrical shapes of molecule images such as spheres and curves transformed into stereogram.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.9-12
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• 2005

Molecular characteristics and rheological properties of cellulose acetate butyrate (CAB), cellulose acetate propionate (CAP) and nitrocellulose (GC-519) which are being widely used as propellants were investigated. Their weight-average molecular weight (Mw) and number-average molecular weight (Mn) were estimated via Gel Permeartion Chromatograpy (GPC). Cellulose derivatices were mixed with di-n-propyl adipate (DNPA) which acted as plasticizer in acetone, and then rheological properties of the mixture of cellulose derivatives and this plasticizer in acetone were investigated at $0^{\circ}C$ by rheometer.

• Polymer Science and Technology
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• v.15 no.4
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• pp.402-410
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• 2004

덴드리머란 중심 (core) 분자로부터 나뭇가지 모양의 단위구조가 반복적으로 뻗어 나오는 거대분자 화합물이다. 3차원적으로는 구형에 가까운 구조를 가지고 있으며 중심부는 상대적으로 낮은 밀도를 가지는 반면, 외곽으로 갈수록 가지의 밀도가 증가한다. 덴드리머는 구조적으로 잘 정의된 거대분자로써, 정확한 분자량과 구조를 예측하여 합성함으로써 나노 크기 의 입자 형성이 용이하다. 덴드리머의 최외곽에 존재하는 말단기는 덴드리머의 표면 성질 및 용해도 등에 결정적인 영향을 미치는 것으로 알려져 있으며, 표면의 밀집된 말단기에 다양한 유도체와 작용기 도입이 가능하다.(중략)

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.18-23
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• 1992

Three solid acid catalysts developed recently are reviewed. Cloverite is a gallophosphate molecular sieve with very large pore, titanium silicate has a specific structure compared with conventional molecular sieves, and Envirocat is prepared for the replacement of aluminium chloride catalyst.

• Optical Science and Technology
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• v.8 no.3
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• pp.10-17
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• 2004

화학 반응은 원자나 분자가 서로 작용하여 결합이 분해되거나 생성되는 동적인 과정이다. 일반적으로 이러한 동적인 과정은 매우 빠른 시간 내에 일어나기 때문에 (보통수 펨토초에서 수 피코초 내에 일어난다) 화학 반응 도중에 나타나는 중간체(transient structure)의 구조 변화나 분자의 움직임을 실시간으로 잡기 위해서는 매우 높은 시간 분해능이 필요하다. 이러한 중간체의 구조 동역학(structural dynamics)은 그 대상이 되는 분자의 화학적/생물적 기능에 매우 중요한 정보를 제공하기 때문에 실시간 분자 동역학 연구는 복잡한 화학적/생물적 시스템의 메커니즘 규명 연구에 필수적이라고 할 수 있다. (중략)

• Analytical Science and Technology
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• v.20 no.4
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• pp.339-346
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• 2007

To search the ninhydrin derivatives that have high chromogenic and fluorogenic properties, molecular holographic quantitative structure property relationship (HQSPR) models on the reactivity between glycine and ninhydrin analogues as latent fingerprint detector were derived and investigated quantitatively. The ${\varepsilon}LUMO$ (e.v.) energy of ninhydrin molecule was an important factor to reactivity of ninhydrin. And, it is suggested that the nucleophilic reaction by orbital-controlled reaction from the frontier molecular orbital (FMO) interaction between glycine and ninhydrin derivatives was more superior than that of electrophilic reaction by charged controlled reaction. The analytical results in atomic contribution maps also shows that the reactivity of ninhydrin was increased by meta-substituents as strong electron withdrawing groups on the benzo ring. Therefore, it is sugested by HQSPR and QSPR model that the 5,6-dinitroninhydrin molecule would increase the reactivity as much as three times as compared to none substituted ninhydrin molecule.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.56-56
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• 2018

토마토에서 과형은 과실의 여러 가지 형질 중에서 눈에 가장 잘 띄는 형질이며, 소비자의 토마토를 구매를 결정하는데 많은 영향을 미치는 중요한 형질이다. 토마토의 과형을 결정하는 여러 가지 유전자 중에 OVATE는 둥근 토마토 과일을 서양 배 모양(pear shape)의 과일로 전환하는데 결정적인 역할을 하는 유전자이다. OVATE 유전자에 의해서 과일의 모양이 변하는 것은 조기종결 코돈을 초래하는 열성 돌연변이에 의해서 유도되며, 단백질의 C-말단 영역이 제거됨에 따라 그 기능을 상실하여 나타나는 현상이다. OVATE 유전자는 주로 식물의 생식기관에서 발현되며, 꽃에서는 개악하기 10일전부터부터 전사체가 만들어지고 발달중인 과실에서는 개약 후 8일까지 전사체를 확인할 수 있다. 토마토 분자육종 과정에서 과형 판별을 위해서 OVATE 유전자 연관 분자표지는 보고된 바 있으나 OVATE 유전자 유래 분자표지는 보고된바가 없다. 본 연구에서 국내에서 육성된 육종 라인들의 resequencing을 통해 OVATE 유전자 염기서열간의 SNP를 발견하고 이들을 dCAPS 마커로 전환하여 분자표지를 개발했다. 이러한 분자표지는 둥근 토마토(round)와 서양 배모양(pear shape)토마토 육종 프로그램의 효율성과 정확성을 향상시키는데 활용할 수 있을 것으로 기대한다.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.219-222
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• 2008

In the search for third generation herbicidal cyclic imide derivatives, the average values of herbicidal activity ($pI_{50}$) in vivo (pre-emergence) of 40 new peroxidizing herbicides, 1-(4-chloro-2-fluoro-5-propargyloxyphenyl)thiourea derivatives (1-40) against rice plant (Orysa sativa) and barnyard grass (Echinochlor crus-galli) were studied. The molecular similarity between protoporphyrinogen IX (protogen) as the substrate of protox enzyme and Urea derivatives (1-40) was discussed quantitatively. The diallyl (20) and 3-nitro substituent (33) showed the selective herbicidal activity against barnyard grass. Allyl substituent (8) and their molecular similarity in dice (S=0.81) showed the highest levels of herbicidal activity ($pI_{50}$=4.71). Also, similarity indices (S) and superimposed volume (C) of protogen and aryl-substituents (21-40) showed good correlation.

• Korean Chemical Engineering Research
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• v.44 no.4
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• pp.329-339
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• 2006

The production of lower olefins from methanol becomes an attractive process because of the rapid increase in crude oil price. This paper reivews the conversion mechanisms of methanol to hydrocarbons over zeolite and SAPO molecular sieve catalysts to understand the formation steps of lower olefins from methanol. The feasibility of the conversion mechanisms such as the direct mechanism based on well-defined intermediates and the hydrocarbon pool mechanism involving hydrocarbon moieties as an active centers is discussed with reepect to the induction period, the selectivity for products and the deactivation phenomena of the methanol conversion. The literature appeered since 1999 for the structure of the hydrocarbon pool and its catalytic role in the methanol conversion are summariged, and the prospect for the methanol-to-olefins process is described.