• 한국자기공명학회논문지
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• 제22권4호
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• pp.115-118
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• 2018

Dipyrromethane 2 functionalized with 3-chloropropyl group on the meso carbon undergoes an unusual intramolecular electrophilic aromatic substitution reaction in the presence of $NaN_3$ instead of a simple nucleophilic substitution reaction. As a result, a new chiral dipyrromethane 1 was synthesized. In this reaction, the ${\beta}$-carbon of the pyrrole ring functions as a nucleophile while the carbon next to the chlorine atom acts as an electrophile. Interestingly, this reaction progresses even in the absence of an acid catalyst. Compound 1 was fully characterized by $^1H-^1H$ and $^1H-^{13}C$ COSY NMR spectroscopic analyses and the high resolution EI mass spectrometry.

• 한국자기공명학회논문지
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• 제10권1호
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• pp.105-114
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• 2006

Purpose: We achieved high resolution MR imaging and spectra of human skin in vitro with using a 14.1 T MRI/MRS system, and evaluated the hydration effect of various cosmetic products by measuring the skin's. moisture concentration. Materials and Methods: We used the Bruker 14.1 T MRI/MRS system with a vertical standard bore that was equipped with a DMX spectrometer gradient system (200 G/cm at a maximum 40 A), RF resonators (2, 5 and 10 mm) and Para Vision software. Spin echo and fast spin echo pulse sequences were employed for obtaining the high resolution MR images. The 3D-localized point resolved spectroscopy (PRESS) method was used to acquire the MR spectra. Results: The high resolution MR images and spectra of human skin in vitro were successfully obtained on a 14.1 T system. The water concentration of human skin after applying a moisturizer was higher than that before applying a moisturizer. Conclusions: The present study demonstrated that the high-resolution MR images and spectra of human skin from a high field NMR instrument could be applicable to evaluating the hydration state of the stratum corneum.

• 한국인쇄학회지
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• 제11권1호
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• pp.85-101
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• 1993

Poly(vinyl cinnamate) had excellent resolution and no dark reaction and high etch resistent. But is was developed in polar solvent. A aqueous-photopolymer was synthesised for improvment of developability. Poly(vinyl cinnamoyl acetate)(PVCiA) and aqueous-PVCiA(PVCiA-s) was prepared and was characterized with H-NMR. The characteristic of sensitivity and developablity of coating was investigated by Grayscale method.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.314-324
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• 1996

A high speed NMR quality evaluation sensor was designed , constructed and tested . The device consists of an NMR spectrometer coupled to a conveyor system. The conveyor was run at speeds ranging from 0 to 250 mm/s. Spectral of avocado fruits and one-dimensional magnetic resonance images of pickled olives were acquired while the samples were moving on a conveyor belt mounted through a 20Tesla NMR magnet with a 20 mm diameter surface coil and a 150 mm diameter imaging coil respectively. Fro a magnetic resonance spectrum analysis, motion through variations in the magnetic field tends to narrow spectral line width just like using sample rotation in high resolution NMR to narrow spectral line width. Spectrum analysis was used to detect the dry weight of avocado fruits using the ratio oil and water resonance peaks. Good correlations maximum r=0.970@ 50 mm/s and minimum r=0.894@250mm/s ) between oil and water resonance peak ratio and dry weight of avocados were observed at speeds ra ging from0 to 250mm/s. For the application of magnetic resonance imaging (MRI) method, the projections were used to distinguish between pitted and non-pitted olives . Effect of fruit position in the coil was tested and coil degree effects were noticed when projects were generated under dynamic conditions. Various belt speeds (up to 250mm/s) were tested and detection results were compared to static measurements. Higher classification errors were occurred at dynamic conditions compared to errors while olives were at rest.

• 대한약침학회지
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• 제20권2호
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• pp.119-126
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• 2017

Objectives: Semecarpus anacardium Linn. is a plant well-known for its antimicrobial, antidiabetic and anti-arthritic properties in the Ayurvedic and Siddha system of medicine. This has prompted the screening of this plant for antibacterial activity. The main aims of this study were to isolate compounds from the plant's seeds and to evaluate their antibacterial effects on clinical bacterial test strains. Methods: The n-butanolic concentrate of the seed extract was subjected to thin layer chromatography (TLC) and repeated silica gel column chromatography followed by elution with various solvents. The compound was identified based on observed spectral (IR, $^1H$ NMR, $^{13}C$ NMR and high-resolution mass spectrometry) data. The well diffusion method was employed to evaluate the antibacterial activities of the isolated acyclic isoprenoid compound (final concentration: $5-15{\mu}g/mL$) on four test bacterial strains, namely, Staphylococcus aureus (MTCC 96), Bacillus cereus (MTCC 430), Escherichia coli (MTCC 1689) and Acinetobacter baumannii (MTCC 9829). Results: Extensive spectroscopic studies showed the structure of the isolated compound to be an acyclic isoprenoid ($C_{21}H_{32}O$). Moreover, the isoprenoid showed a remarkable inhibition of bacterial growth at a concentration of $15{\mu}g/mL$ compared to the two other doses tested (5 and $10{\mu}g/mL$) and to tetracycline, a commercially available antibiotic that was used as a reference drug. Conclusion: The isolation of an antimicrobial compound from Semecarpus anacardium seeds validates the use of this plant in the treatment of infections. The isolated compound found to be active in this study could be useful for the development of new antimicrobial drugs.

• 광물과 암석
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• 제35권1호
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• pp.65-73
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• 2022

지구/행성 내부의 다양한 지질학적 과정을 이해하기 위해서는 고온-고압 환경에서 지구 내부 구성물질의 특성을 이해하는 것이 필수적이다. 이러한 고압환경을 생성하기 위하여 사용되는 멀티 앤빌 프레스(multi-anvil press)는 주로 상부맨틀조건의 극한 상황을 재현하는데 사용된다. 멀티 엔빌프레스의 지질학적 사용을 위한 필수 보정 과정 중 하나는 압력을 생성하기 위한 프레스의 유압과 실제로 시료에 가해지는 압력 사이의 관계인 압력-부하 보정(pressure-load calibration)이다. 압력-부하 보정은 일반적으로 고온-고압 조건에서는 결정질 물질의 상전이를 이용해서 이루어지는데, 고온에서의 경우와 달리 저온(상온)의 경우 상전이 과정이 상대적으로 비효율적이므로 압력-부하 보정의 다른 방법론이 요구된다. 본 연구에서는 파이로프 조성(Mg₃Al₂Si₃O₁₂)의 비정질(비정질 파이로프)의 상온에서의 압축(cold compression)에 따라 발생하는 영구적인 고밀도화 현상(permanent densification)과 그 기원이 되는 알루미늄 배위 환경의 변화를 고해상도의 ²⁷Al MAS 및 3QMAS NMR 분광분석을 통해 정량화하고, 이로부터 압력에 따른 알루미늄의 배위수 변화를 이용해 14/8 HT 조립세트(assembly set)와 1,100톤 멀티 앤빌 프레스에 대한 상온에서의 압력-부하 보정을 수행하였다. 본 연구는 NMR분광분석을 이용하여 압력보정을 수행한 최초의 연구결과이며, 비정질 파이로프의 압축-감압에 따른 원자 단위에서의 비가역적 구조 변화는 섭입대 환경과 같은 저온 고압 환경에서 비정질 물질이 겪는 변화와 그에 따른 지질학적 현상의 이해고양에 실마리를 제공한다.

• 한국자기공명학회논문지
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• 제24권4호
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• pp.104-116
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• 2020

Fipronil, the phenylpyrazole insecticide, is effective and used in various fields. Especially, fipronil was reliable because it was known to be specific on invertebrate animals than vertebrate animals including mammals. However, fipronil had potential risks that affect vertebrate animals as it blocks the gamma-aminobutyric acid (GABA) receptors that also exists in vertebrates as well as invertebrates. Therefore, it was necessary that harmful effects of fipronil on vertebrates are clarified. For this purpose, the zebrafish (Danio rerio) were used on behalf of vertebrate animals in present study. The zebrafish were exposed to 5 ㎍/L, 25 ㎍/L, and 50 ㎍/L of fipronil during 12, 24 and 72 hours. To closely observe toxic process, 12 hours and 24 hours of additional time point were set in the exposure test. Nuclear magnetic resonance (NMR)-based metabolomics is an approach to detect metabolic changes in organism resulted from external stimuli. In this study, NMR-based metabolomics showed the metabolic changes in zebrafish caused by fipronil exposure. Metabolic analysis revealed that fipronil interfered with energy metabolism and decreased the antioxidant ability in zebrafish. Antioxidant ability decline was remarkable at high exposure concentration. In addition, metabolic analysis results over time suggested that reactions for alleviating the excessive nerve excitation occurred in zebrafish after fipronil exposure. Through this study, it was elucidated that the adverse effects of fipronil on vertebrate animals are evident. The risk of fipronil on vertebrates can be no longer ignored. Moreover, this study has a meaning of practically necessary research for organism by examining the effects of fipronil at low concentrations existed in real environment.

• 공업화학
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• 제18권4호
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• pp.330-336
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• 2007

본 연구에서는 $BF_3$를 함유한 키랄성 코발트 살렌 촉매를 합성하고 비대칭촉매특성을 평가하였다. 촉매의 구조를 결정하기 위하여 NMR, UV 및 ESCA분석을 수행하였다. 합성한 촉매는 여러 종류의 에폭사이드 유도체의 가수분해 속도차에 의한 비대칭 고리열림반응에 적용하여 그 활성과 선택성을 조사하였다. 살렌과 $BF_3$의 비를 다르게 하여 합성한 촉매는 전혀 다른 촉매 활성을 나타내었으며, 그 비를 2 : 1로 하여 합성한 2분자구조의 살렌착체 촉매는 물을 친핵체로 하는 라세믹 에폭사이드의 고리 열림을 통하여 99 %ee 이상의 매우 높은 광학선택성을 보였다. 특히 2분자형의 살렌 촉매는 단분자형의 촉매에 비하여 촉매량을 적게 첨가하여도 현저히 향상된 촉매활성을 나타내었고 얻어진 생성물의 분리과정에서 라세믹화를 유발시키지 않았다. 본 연구에서 적용한 촉매시스템은 키랄 에폭사이드 및 1,2-디올 중간체의 제조에 매우 효과적이었다.

• Journal of the Korean Wood Science and Technology
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• 제48권6호
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• pp.888-895
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• 2020

Ulmus genus has excellent various physiological activities, including anti-ulcer, antioxidant, antibacterial, anti-cancer, immunity, and homeostasis maintenance effects, and it is known to have many additional drug effects And one of reasons for these excellentbiological activities is a flavan-3-ol chemical group in Ulmus genus. In this study a new flavan-3-ol compound was identified in Ulmus davidiana var. japonica. A flavan-3-ol,(2R,3S)-7-[(2S,3R,4R)-3,4-dihydroxy-4-(hydroxymethyl)oxolan-2-yl]oxy-2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5-diol, named as catechin 7-O-beta-D apiofuranoside, was isolated from the stems and barks of Ulmus davidiana var. japonica for. suberosa, which is a species belonging to the genus Ulmus, growing throughout the Korea peninsula. The structure was elucidated by various spectroscopic methods including high-resolution TOF mass spectrometry, ¹H-NMR and ¹³C-NMR spectrometry and comparison with chemical structures of defined compounds.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.134-143
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• 2010

We studied the hydrogen-bonded $TlH_2PO_4$ (TDP) ferroelectrics treated with the proton-beam bombardment. The TDP material was irradiated with 1-MeV proton beam at a dose of $10^{15}/cm^2$. In order to analyze the hydrogen environment in TDP, we carried out the $^1H$ high resolution nuclear magnetic resonance (NMR) - i.e., Combined Rotation And Multiple Pulse Spectroscopy (CRAMPS) measurement. The isotropic chemical shift of hydrogen indicates its displacive property is related to the $PO_4$ lattice deformation which occurs throughout the antiferroelectric-, the ferroelastic- and the paraelastic-phase transitions. The temperature dependence of $\sigma_{iso}$ reveals the electronic charge redistribution is induced by the proton-beam irradiation and the elastic property.