• 반도체디스플레이기술학회지
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• 제7권3호
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• pp.35-39
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• 2008

We study the interaction of acetone molecule $[(CH_3)_2CO]$ on Si(001) surface using density functional theory. An acetone molecule is adsorbed on a Si atom of the Si dimer of the Si(001) surface. The adsorption of the acetone molecule on the Si atom at lower height between the two Si atoms of the dimer is more favorable than that on the Si atoms at upper height. Then we calculate an energy variation of dissociation and four-membered ring structures of the acetone molecule adsorbed on the Si surface. Total energy difference between the two structures is about 0.05 eV, indicating that the two structures are almost equally stable. Energy barrier exists when a hydrogen atom is dissociated and adsorbed on the other Si atom of the dimer, while energy barrier does not exist when the adsorbed acetone molecule changes to four-membered ring structure, except for the rotation of the acetone molecule along z-direction. Therefore, four-membered ring structure is kinetically more favorable than the dissociation structure when the acetone molecule is adsorbed on the Si(001) surface.

• 대한화학회지
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• 제39권5호
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• pp.329-337
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• 1995

산촉매하에서 중합반응을 하는 고에너지를 함유한 옥세탄 유도체들을 ab initio HF/3-21G 방법으로 구조, 전하, 정전기 전위 등을 계산하고 그 결과를 고찰하였다. 계산 결과에 의하면 큰 치환체가 도입되거나 양성자화나 $BF_3$ 착물화에 의해 옥세탄 고리의 구조는 상당히 변화하며, 이것은 정전기적 상호작용이나 구조적 척력으로 설명할 수 있다. 옥세탄 유도체들의 친핵성 및 염기성은 옥세탄 산소원자의 음전하와 최소 정전기 전위의 크기로 설명할 수 있다. 공중합하의 옥세탄 유도체들의 반응성은 (1) 옥세탄 유도체의 염기성과 (2) 옥세탄 유도체의 HOMO 에너지와 활성화 옥세탄 중합 고리의 LUMO 에너지의 차에 의해 설명되어진다. 계산에 의하면 3-azidomethyl-3-methyl oxetane (AMMO)이 3-nitratomethyl-3-methyl oxetane (NMMO)보다 염기성이 크며, AMMO나 NMMO 사슬에 관계없이 반응성이 큼을 알 수 있다. 이 계산 결과는 이미 알려진 실험 결과들과 잘 일치한다.

• 폴리머
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• 제31권4호
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• pp.273-277
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• 2007

할로겐을 포함하지 않은 난연제를 개발하기 위하여 cyclophosphazene 유도체들을 합성하여 이들을 ABS를 위한 난연제로 사용하여 보았다. Chlorocyclophosphazene에 phenol, catechol, aniline, 1,2-diaminobenzene 등을 반응시켜 각각의 유도체들을 합성하였으며 이들이 ABS에 얼마나 잘 난연성을 나타내는지를 UL94, LOI 등으로 살펴보았다. 이들 난연제를 함유하는 ABS 시료의 물성도 알아보았다. Catechol로부터 합성된 유도체가 가장 우수한 난연 결과를 보여주었으며 phenol로부터 합성된 유도체의 경우에는 novolac과 같은 고분자와 혼합한 다음에 첨가하면, 같은 양의 첨가로 더 우수한 난연성을 보여 주었다.

• 한국자기공명학회논문지
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• 제21권4호
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• pp.139-144
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• 2017

Ni(II) containing coenzyme F430 catalyzes the reduction of $CO_2$ in methanogen. Macrocyclic Ni(II) complexes with N,O shiff bases have been received a great attention since metal ions play an important role in the catalysis of reduction. The reducing power of metal complexes are supposed to be dependent on oxidoreduction state of metal ion and structural properties of macrocyclic ring moiety that can enhance electrochemical properties in catalytic process. Six different ${\alpha}$-oximinoketone compounds, precursor of macrocyclic ligands used in $CO_2$ reduction coenzyme F430 model complexes, were synthesized with yields over 90% and characterized by NMR. The molecular geometries of ${\alpha}$-oximinoketone analogues were fully optimized at Beck's-three-parameter hybrid (B3LYP) method in density functional theory (DFT) method with $6-31+G^*$ basis set using the ab initio program. In order to understand molecular planarity and substitutional effects that may enhance reducing power of metal ion are studied by computing the structure-dependent $^{13}C$-NMR chemical shift and comparing with experimental results.

• 약학회지
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• 제42권1호
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• pp.12-24
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• 1998

For the development of new cephalosporin antibiotics with aminothiazolcarboxymethylethoxyimino moiety on the C-7 position and tetrazolymethyl moiety on the C-3 position of cephe m ring, 7${\beta}$-[(Z)-2-(2-aminothiazol-4-yl)-2-(1-carboxy-1-methylethoxyimino)acetamido]-3-[5-(substituted)tetrazol-2-yl]methyl-3-cephem-4-carboxylic acids(28-35) were synthesized. These compounds were tested for antimicrobial activity in vitro against Gram(+) and Gram(-) bacteria. They showed remarkable antibacterial activity against Escherichia coli AB 1157, Escherichia coli AB 0111, Escherichia coli BE 1186, Micrococcus luteus ATCC 9341, Salmonella typhimurium TV 119, Salmonella typhimurium SL 1102, Staphylococcus aureus IFO 12732, Staphylococcus aureus R-209, but these compounds were not active against Pseudomonas aeruginosa N-10.

• Applied Microscopy
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• 제28권2호
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• pp.193-205
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• 1998

The Urechis unicinctus sperm and spermatogenic cells prepared from the testis are investigated to identify $\alpha-tubulin$ of axoneme microtubules using mouse monoclonal $anti-\alpha-tubulin$ as the first Ab and Gold(10nm) conjugated goat anti-mouse IgG as the Ab marker. The Ag-Ab reaction analyzed excellently the localization of $\alpha-tubulin$ and the gold particles incorporated with the proximal and distal centrioles, manchette microtubules, and flagellum. The gold particles can be also observed in the spermatogenic cells while the cells are still in sperm ball which is composed of a somatic cell and spermatogenic cells. The sperm ball is the functional unit of sperm production in U unicinctus testis. The spermatids are developed from the spermatogenic cells in the sperm ball and released into the testis cavity through a cortical cytoplasmic opening. The spermatid architectures are similar with the mature sperm of the testis cavity in aspects of shape of discoid acrosome, degree of nuclear condensation and ring type of mitochondrion. However, the distal centriole connecting with the flagella can be observed from the mature sperm while the both proximal and distal centrioles reveal only in the spermatids. The proximal centriole is directly connected with nuclear outer membrane during the stage of nuclear condensation and oriented perpendicularly to the distal centriole whose axis coinciding with the longitudinal axis of the spermatozoon. There are indications that the distal centriole is intimately associated with the polymerization of the flagellum. The manchette microtubules appear during spermatid development but the mature sperm have round head and no conspicuous middle piece.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.74-74
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• 2003

We report here the results on N-acetyl-N'-methylamide of oxazolidine (Ac-Oxa-NHMe) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level of theory with the 6-3l+G(d) basis set. The displacement of the $\square$-CH$_2$ group in proline ring by oxygen atom has affected the structure of proline, cis$\^$∼/ trans equilibrium, and rotational barrier. The up-puckered structure is found to be prevalent for the trans conformers of the Oxa amide. The higher cis populations of the Oxa amide can be interpreted due to the longer distance between the acetyl methyl group and the 5-methylene group of the ring for the trans conformer of the Oxa amide than that of the Pro amide. The changes in charge of the prolyl nitrogen and the decrease in electron overlap of the C$\^$∼/ N bond for TS structures seem to play a role in lowering rotational barriers of the Oxa amide compared to that of the Pro amide. The calculated preferences for cis conformers in the order of Oxa > Pro amides and for trans-to-cis rotational barriers in the order of Pro > Oxa amide in water are consistent with experimental results on Oxa-containing peptides. The pertinent distance between the prolyl nitrogen and the N$\^$∼/ H amide group to form a hydrogen bond might indicate that this intramolecular hydrogen bond could contribute in stabilizing the TS structures of Oxa and Pro amides and play a role in prolyl isomerization.

• 대한수학회보
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• 제56권3호
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• pp.729-743
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• 2019

In this paper, we introduce strongly quasi primary ideals which is an intermediate class of primary ideals and quasi primary ideals. Let R be a commutative ring with nonzero identity and Q a proper ideal of R. Then Q is called strongly quasi primary if $ab{\in}Q$ for $a,b{\in}R$ implies either $a^2{\in}Q$ or $b^n{\in}Q$ ($a^n{\in}Q$ or $b^2{\in}Q$) for some $n{\in}{\mathbb{N}}$. We give many properties of strongly quasi primary ideals and investigate the relations between strongly quasi primary ideals and other classical ideals such as primary, 2-prime and quasi primary ideals. Among other results, we give a characterization of divided rings in terms of strongly quasi primary ideals. Also, we construct a subgraph of ideal based zero divisor graph ${\Gamma}_I(R)$ and denote it by ${\Gamma}^*_I(R)$, where I is an ideal of R. We investigate the relations between ${\Gamma}^*_I(R)$ and ${\Gamma}_I(R)$. Further, we use strongly quasi primary ideals and ${\Gamma}^*_I(R)$ to characterize von Neumann regular rings.

• Journal of Chest Surgery
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• 제30권6호
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• pp.598-606
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• 1997

1994년 9월부러 1995년 8월까지 일년동안 부천 세종병원에서 시행된 승모판막질환 수술은 총 136례였으 며 이중 인공판륜을 사용하여 판막성형술을 시행된 44례를 대상으로 평가하였다 이 44례의 평균 연령은 38.2세(범위: 5세~63세)였으며 남성이 18례 여성이 26례였다, 사용된 인공판륜은 Carpentier ring이 32례, Dmm ring 이 12례였다. 판막질환의 원인은 류마치스가 30례(68%), 퇴행성 질환에 기인한 것이 13례(30%)였으며, 1례는 선천성 승 모판 부전증이었다. 판막질환의 형태로 보면 승모판막부전증이 33례(76%),승모판 협착증이 2 례(5%), 승모판 협착부전증이 9례(19%) 있었다. Carpentier의 기능적 분류는 I형이 5례(11%), II형이 24례(55%), III형이 4례(9%) 있었으며, II형과 III형의 혼합형이 11례(25%)에서 관찰되었고, 매 환자당 평균 3.7가지의 병변이 있었다. 승모판에 시행한 수술 수기는 전례에서 인공판륜성형술을 시행하였으며 한 환자 당 평균 3.4가지의 수기 를 사용하였다. 수술 사망은 2례에서 발생하였으며, 수술 후 승모판 부전증이 진행되어 2주에 시행한 재수술이 일 례 있 었다. 12개월의 추적 관찰에서 수술 전후의 NYHA 기능적 鈞畢\ulcorner평균 3.0에서 1.3으로 개선되었다. 심장 초음파 검사에서 술후의 승모판 면적은 2.07$\pm$0.11 cm2(평균 $\pm$ 표준오차)이었으며, 좌심실 수축력의 호전을 보였고, 판막부전의 정도는 전혀 판막부전 소견이 없어진 경우가 23례(53%), 경미한 폐쇄부전이 있는 경우가 18례(42%)였고, II도 부전의 소견을 보인 례가 2례(5%) 있었다.

• 대한수학회보
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• 제57권5호
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• pp.1205-1213
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• 2020

Let R be a commutative ring with 1 ≠ 0. In this paper, we introduce a subclass of the class of 1-absorbing primary ideals called the class of strongly 1-absorbing primary ideals. A proper ideal I of R is called strongly 1-absorbing primary if whenever nonunit elements a, b, c ∈ R and abc ∈ I, then ab ∈ I or c ∈ ${\sqrt{0}}$. Firstly, we investigate basic properties of strongly 1-absorbing primary ideals. Hence, we use strongly 1-absorbing primary ideals to characterize rings with exactly one prime ideal (the UN-rings) and local rings with exactly one non maximal prime ideal. Many other results are given to disclose the relations between this new concept and others that already exist. Namely, the prime ideals, the primary ideals and the 1-absorbing primary ideals. In the end of this paper, we give an idea about some strongly 1-absorbing primary ideals of the quotient rings, the polynomial rings, and the power series rings.