• 한국결정성장학회지
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• 제9권2호
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• pp.224-230
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• 1999

콜로이드성 알루미나 분말 입자들의 현탁액에서 입자들의 응집현상을 시뮬레이션 하였다. 현탁액 속의 알루미나 분말 입자들은 입자간 포텐셜 에너지를 가지고 있으며 시간이 경과함에 따라 현탁액으 전체적인 에너지를 감소시키는 방향으로 시스템을 변화시킨다. 현탁액 속의 분말 입자들의 응집 현상을 입자간 포텐셜 곡선의 유형에 따라 관찰하였다. 단거리에서 강한 친화 포텐셜 에너지를 가지는 입자들은 무정형 망목 응집구조를 유도하며 응집체의 크기가 작아지고 단거리에서 강한 척력 포텐셜 에너지와 장거리에서 상대적으로 강한 친화 포텐셜 에너지를 가지는 분말 입자들이 밀집충진 응집구조에 접근하고 응집체의 크기가 상대적으로 커지게 된다. 입자간 에너지 분포에 강한 반발에너지 장벽이 존재하는 경우에 입자들이 응집함에 따라 이러한 에너지는 장벽이 사라지게 되며 이러한 현상은 입자의 응집패턴의 변화를 의미한다.

• 한국자기공명학회논문지
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• 제18권1호
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• pp.24-29
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• 2014

Atomistic molecular dynamics (MD) simulation has become mature enabling close approximation of the real behaviors of biomolecules. In biomolecular NMR field, atomistic MD simulation coupled with generalized implicit solvent model (GBIS) has contributed to improving the qualities of NMR structures in the refinement stage with experimental restraints. Here all-atom force fields play important roles in defining the optimal positions between atoms and angles, resulting in more precise and accurate structures. Despite successful applications in refining NMR structure, however, the research that has studied the influence of force fields in GBIS is limited. In this study, we compared the qualities of NMR structures of two model proteins, ubiquitin and GB1, under a series of AMBER force fields-ff99SB, ff99SB-ILDN, ff99SB-NMR, ff12SB, and ff13-with experimental restraints. The root mean square deviations of backbone atoms and packing scores that reflect the apparent structural qualities were almost indistinguishable except ff13. Qualitative comparison of parameters, however, indicates that ff99SB-ILDN is more recommendable, at least in the cases of ubiquitin and GB1.

• 대한의용생체공학회:의공학회지
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• 제16권1호
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• pp.9-16
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• 1995

Biodegradable poly (I ,4-butanediol succinate) (PBS) was synthesized from 1,4-butanediol and succinic anhydride. The glass transition temperature of poly (I, 4-butanediol succinate) was revealed at $73^{\circ}C$. The crystallization and cold crystallization of the polymers were investigated as a function of holding time in melt state, cooling rate. reheating, and molecular weight. Chain scission and/or cmsslinking did not occur in the melt state at var.ious holding times. Slower scanning rate can allow more times for nucleation, rearrangement, and packing of the polymer chain, so the onset temperature of crystallization from the melt was increased. PBS crystallized from the melt was found to have spherulitic structure. The degradation behavior of PBS was studied under basic conditions and with microorganisms using the modified ASTM method. In the basic solution. PBS lost up to 85% of its mass within two days. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.191-191
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• 2006

The structures of the mesophases and their subunits of PS-b-P4VP in a toluene solution were studied by using SAXS, TEM and GIFT methods. The hierarchical structures of PS-b-P4VP, such as the individual micelle, the face-centered cubic (fcc) and body-centered cubic (bcc) structures and the lamellar structure, were identified for the first time. The diameter of the micelle core was ${\sim}80\;%$ of the most extended chain length of the core chain, suggesting that the core chains were quite stretched. The stretched chain in the core caused the core of the micelle to be not homogenous with a higher density at the center than at the outer part. As the concentration level increases, the fcc and both fcc and bcc appear for the packing of the micelles of PS(3.3k)-b-P4VP(4.7K) and PS(12K)-b-P4VP(11.8K), respectively. The lamellar structure was also identified, with a further increase in the concentration for PS(3.3k)-b-P4VP(4.7K). These hierarchical structures were also identified via TEM images.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.77-77
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• 2015

Metallic glass alloys having dense packing structure have short range ordered structure with long range homogeneity. Therefore, they can provide complete corrosion protection and unique electrical properties. Recently, metallic glass thin films have received much attention to extend its application fields combining with PVC coating technologies. The metallic glass thin films can change the surface properties of the conventional bulk materials which need anticorrosion properties. However, multi-component alloying targets are required to fabricate the metallic glass thin films because metallic glass alloys contain more than three elements. Recently, many researchers have been reported the properties of the metallic glass thin films synthesized with multi-cathode systems or amorphous target. But, it is difficult to fabricate the large sized sputtering targets for mass production equipment with high toughness and thermal stability. In this study, newly developed sputtering target with glass forming ability and the properties of the metallic glass thin films will be introduced with respect to the various application fields such as bipolar plate in PEM fuel cell and decorative coatings for electric device and construction fields.

• 대한화학회지
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• 제63권1호
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• pp.29-36
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• 2019

A potentially tetradentate Schiff base ligand, 2-((2-((pyridin-2-ylmethylene)amino)ethyl)amino)ethan-1-ol (PMAE), and its cadmium(II) complex, [$Cd(PMAE)I_2$] (1), were prepared and characterized by elemental analysis, FT-IR, Raman, $^1H$ and $^{13}C$ NMR spectroscopies and single-crystal X-ray diffraction. In the crystal structure of 1, the cadmium atom has a slightly distorted square-pyramidal geometry and a $CdN_3I_2$ environment in which the PMAE acts as an $N_3$-donor. In the crystal packing of the complex, the alcohol and amine groups of the coordinated ligands participate in hydrogen bonding with iodide ions and form $R^2{_2}(14)$ and $R^2{_2}(8)$ hydrogen bond motifs, respectively. In addition to the hydrogen bonds, the crystal network is stabilized by ${\pi}-{\pi}$ stacking interactions between pyridine rings. The thermodynamic stability of the isolated ligand and its cadmium complex along with their charge distribution patterns were studied by DFT and NBO analysis.

• 전기전자학회논문지
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• 제27권1호
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• pp.93-102
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• 2023

악성코드 분석을 위한 기술 중 하나로 실행 프로그램의 함수 호출 관계를 시퀀스 또는 그래프 작성한 후, 그 결과를 분석하는 기술이 제안되었다. 이러한 기술들은 일반적으로 실행 프로그램 파일의 정적 분석을 통해 함수 호출 코드를 분석하고, 함수 호출 관계를 시퀀스 또는 그래프로 정리한다. 그러나 난독화 된 실행 프로그램의 경우, 실행 프로그램 파일의 구성이 표준구성과 다르기 때문에 정적분석 만으로는 함수 호출관계를 명확히 분석하기 어렵다. 본 논문에서는 난독화 된 실행 프로그램의 함수 호출관계를 분석하기 위한 동적 분석 방법을 제안하고, 제안된 기술을 이용하여 함수 호출관계를 그래프로 구성하는 방법을 제안한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.823-828
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• 2002

Concrete used up to date semipermanent architecture material but now day concrete early deterioration emboss social issue because of construction structure and environmental factor. so, many study of deterioration concrete construction improve durability used impregnation alkalization agent. Impregnation alkalization agent deterioration concrete construction spray infiltration or diffusion improve alkali and filler inter minuteness void elaborateness constitution concrete. but many study of harding concrete change inter minuteness void that Is insufficiency also, To study of method recover shape impregnation alkalization agent apply deterioration concrete construction. impregnation alkalization agent infiltration according to test of porosity, premeameter, absorption.

• 한국초전도ㆍ저온공학회논문지
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• 제3권1호
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• pp.69-73
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• 2001

For developing the cryogenic air separation unit, it requires some technology such as basic process design. equipment design and manufacturing based on the cryogenic physical properties and separation theory. In this study, we developed a process and equipment for producing high purity nitrogen which has the production capacity of 1600N㎥/h under 1 ppm $O_2$ and $H_2O$. Also we found that the number of theoretical plate(NTP) of distillation column was 44 and maximum nitrogen recovery ration of this process was 42% from the process simulation. The performance test was also carried out for the nitrogen recovery ratio and equipment efficiency. The results showed that the optimum nitrogen recovery was 41% and the maximum equipment efficiency was attained.

• ETRI Journal
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• 제7권4호
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• pp.11-14
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• 1985

바이폴라 소자로 구성된 회로가 양호한 특성을 갖기 위해서는 개별 소자의 동작 속도, 집적도 및 전력 소비 특성이 좋아야 한다. 그런데 지금까지 주로 사용해온 기존의 SBC 바이폴라 트랜지스터로는 이들 특성을 개선하는 데는 한계가 있었다. 일반적으로 바이폴라 트랜지스터는 면적이 줄어듦에 따라 이들 특성이 개선되므로 본 연구에서는 SBC 방법과는 다른 PSA 공정 방법을 개발하였다. 즉, 소자 격리에서의 종래의 PN 접합에 의한 방법과 다른 산화막에 의한 방법을 도입하였고 또한 에미터, 베이스 사이의 거리를 최소로 줄이기 위하여 다결정 실리콘에 의한 polysilicon self-align 방법으로 에미터 및 베이스를 형성시켰다.