• 분석과학
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• 제8권4호
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• pp.535-538
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• 1995

This study employs the variety of mixtures of XAD resin and active carbons as concentration base for solid phase extraction (SPE) which has been widely used to preconcentrate and purify phenol and chlorophenols in determination of environmental water samples. In this study, we employed variety of mixtures of copolymer based XAD-4 resin with active carbons. This cartridges shows advantages of both materials, such as better affinity to phenol by active carbon and better mechanical stabilities from XAD resin. The better enrichment factor, pretreatment time, recoveries and limit of detection (LOD) were achieved by the attempts to pack precolumns with both meterials for preconcentration.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1281-1283
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• 2003

Proteins in highly oriented lipid bilayer samples are useful to study membrane protein structure determination. Planar lipid bilayers aligned and supported on glass slide were prepared. These stack of glass slide with planar lipid bilayers are not well fit for commercial solid-state NMR probe with round coil. Therefore, homebuilt solid-state NMR probe was built and used for a stack of thin glass plates and RF coil is wrapping directly around the flat square sample. The overall filling factor of the coil is much better and the large surface area enhances the extent to orientation by providing uniform environments for the phospholipids and the high ratio of circumference to area reduces edge effects. $^1H\;and\;^{15}N$ double resonance probe for 400 MHz NMR (9.4T) with a flat coil (coil size: 11 mm ${\times}$ 20 mm ${\times}$ 4 mm) is constructed and tested.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.93-97
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• 1991

Rate constants have been measured spectrophotometrically for the reactions of alkali metal ethoxides with 4-nitrophenyl benzoate, S-4-nitrophenyl thiobenzoate and 4-nitrophenyl thionbenzoate in ethanol at 25$^{\circ}$C. Substitution of S for O in the leaving group has not affected reactivity significantly, while the effect of the similar replacement in the acyl group has led to rate decrease by a factor of 10, although pronounced rate enhancements have been expected for both systems. The replacement of O by a polarizable S has also influenced the reactivity of the esters toward alkali metal ethoxides, i.e. the reactivity decreases as the size of the metal ion decreases. The alkali metal ions have showed inhibition effect instead of catalytic effect which would have been expected for the present system. The effect of replaced sulfur atom on the reactivity for the present system is attributed to the nature of hard and soft acids and bases.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.122-127
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• 1992

Some perovskites $A($Cu_{1}3}Nb_{2}3}$)O_3(A=$Sr^{2+}$$, $Ba^{2+}$ and $Pb^{2+}$) and their series of mixed perovskites have been prepared by solid state reaction. Single perovskite phase was obtained in Sr or Ba rich samples, but pyrochlore phase was found in Pb rich samples. The stability of perovskite phase is dependent on the ionicity of bonding as well as the tolerance factor. All the obtained perovskites have tetragonal symmetry distorted by Jahn-Teller effect of $Cu^{2+}$. In the case of $Sr(Cu_{1}3}Nb_{2}3})O_3$, some superlattice lines caused by threefold enlarging of fundamental unit cell were observed. And, the symmetry of B site octahedron and the bonding character of B-O bond have been studied by IR, ESR and diffuse reflection spectroscopy. It appeared that the symmetry and the bonding character are influenced by such factors as the size and the basicity of A cation.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.860-864
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• 1994

2nd-order rate constants have been measured spectrophotometrically for the reactions of 4-nitrophenyl benzoate (1), S-4-nitrophenyl thiobenzoate (2) and 4-nitrophenyl thionbenzoate (3) with alkoxides, aryloxides and thioaryloxides in absolute ethanol at 25.0 ${\pm}0.1$${\circ}C$. The substitution of O by polarizable S in the leaving group has little affected the reactivity of 2 toward the charge localized species (eg. $EtO^-$ and $CF_3CH_2O^-$), while the effect of the similar replacement in the carbonyl group has led to a decrease in reactivity by a factor of 10. However, the reactivity of these esters toward charge delocalized aryloxides has been found to be in the order $1<3{\le}2$. The effect of replaced sulfur atom on reactivity becomes more significant for the reaction with polarizable thioaryloxides, i.e. the reactivity increases in the order $1<2{\ll}3$. The difference in reactivity for the present system is attributed to a polarizability effect.

• Bulletin of the Korean Chemical Society
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• 제10권4호
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• pp.335-339
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• 1989

Cholesteryl methyl ether$(CH_3OC_{27}H_{45})$ crystallizes in the monoclinic space group $P2_1$with a = 11.740 (8), b = 7.576 (5), c = 15.492 (10)${\AA},\; {\beta}\;= 110.39 (5)^{\circ}$, Z = 2, Dc = 1.03 g/$cm^3$ and Do = 0.96 g/$cm^3$. The intensities were collected on a Nonius CAD-4 diffractometer with Nb-filtered Mo-$K_{\alpha}$ radiation. The structure was solved by direct methods and refined by full matrix least-squares methods. The final R factor was 0.085 for 1479 observed reflections. Compared with other cholesterol derivatives, the cholesteryl ring and tail region of the molecule are normal. The molecular long axes are parallel to the [101] axis and molecules are packed together in a similar way to those in cholesteryl cliloride and bromide.

• 농약과학회지
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• 제13권4호
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• pp.249-255
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• 2009

본 실험은 우리나라에서 파에 등록되어 사용중인 농약 중 pyridalyl, kresoxim-methyl, spinosad, flufenoxuron, difenoconazole, metconazole, tebufenozide를 시험농약으로 하여 건조계수와 가공계수를 구하기 위해 파에 대한 2군데 포장시험을 수행하여 $60^{\circ}C$에서 건조한 후 건조 전후 차의 수분함량을 측정하고 잔류농약을 분석하였다. 파의 평균 수분 함량은 건조 전은 89.3%, 건조 후는 10.2%이였으며, 2포장의 평균 가공계수는 pyridalyl은 7.24, kresoxim- methyl은 2.85, spinosad은 7.43, flufenoxuron은 3.17, difenoconazole은 4.38, metconazole은 2.40, tebufenozide은 8.13으로 나타났고, 2포장의 평균 감소계수는 pyridalyl은 0.87, kresoxim-methyl은 0.35, spinosad은 0.88, flufenoxuron은 0.38, difenoconazole은 0.52, metconazole은 0.29, tebufenozide 0.98로 나타나 전반적인 농약잔류량은 건조하는 과정에서 감소하는 경향이었다.

• 생명과학회지
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• 제26권12호
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• pp.1360-1366
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• 2016

Heat shock proteins (HSPs)은 다양한 생리학적인 또는 환경적 스트레스에 응답하여 유도된다. 그러나 HSPs의 전사 활성은 heat shock factors (HSFs)에 의해 조절 된다. 현재 연구에서는 붕어와 마우스의 간세포 배양에서 열 스트레스에 의한 heat shock factor 1 (HSF1)의 패턴 차이와 heat shock protein 70 (HSP70)의 발현을 면역분석법을 이용하여 조사하였다. 붕어의 간세포는 $33^{\circ}C$에서 trimer를 이루지만 마우스의 간세포는 $42^{\circ}C$에서 trimer를 이루었다. 이 연구는 붕어와 마우스의 HSF1은 열 스트레스로부터 다른 온도에서 반응을 한다는 것을 보여준다. 또한 재조합 단백질을 이용하여 붕어와 인간의 HSF1의 온도에 따른 활성 조건을 CD spectroscopy와 면역분석을 이용하여 조사하였다. 이러한 결과들은 인간과 마우스 HSF1과 붕어의 HSF1은 온도에 의한 활성 변화를 보이지만 그들의 최적 활성 온도는 다르다는 것을 알 수 있다.

• 한국환경과학회지
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• 제23권8호
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• pp.1507-1512
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• 2014

Recognition of Korean pre-service elementary school teachers concerning the factor for the environmental class was investigated and analyzed by the factorial analysis. Korean pre-service elementary school teachers are aware of the factor of 'participation in environment' as well as the factor of 'environmental knowledge' for the environmental class. Furthermore, they had a very positive attitude about the factor of 'participation in environment'.

• Applied Biological Chemistry
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• 제36권6호
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• pp.553-556
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• 1993

대두 종자 저장 단백질의 일종인 ${\beta}-conglycinin$의 ${\alpha}'$subunit 유전자 upstream 영역에 결합하여 전사 조절에 관여하리라 추정되는 SEF3(soybean embryo factor 3)의 발현을 조사하기 위하여 대두 핵 추출물을 조제하였다. 두개의 AACCCA를 포함하는 SE3 DNA를 $^{32}P$로 표지한 후 gel mobility shift assay 탐침으로 이용하여 대두 발달 과정 중의 SEF3의 역가를 조사하여 본 결과, 개화 후 16일부터 32일까지의 역가는 증가하나 SE3-SEF3 결합체 이동도는 감소하였다. 핵 추출물을 alkaline phosphatase 처리하면 결합체의 이동도가 다시 증가하였으나 이 현상은 phosphate에 의해 저해되었다. 그리고 결합체의 형성은 반응 pH 6.8과8.5사이에서는 큰 영향을 받지 않았다.