• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.266-269
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• 1985

The dissociation constants(K) of m-chloroanilinium ion in water-ethanol mixture, where the volume percentage of water is 89.5%, were evaluated by UV-spectroscopic method at $20{\sim}50^{\circ}C$, up to 1500 bars with changing ionic strength from 0.04 to 0.10 mol $kg^{-1}$ by use of acetate buffer. K values enhance with increasing ionic strength and temperature, but decrease with elevating pressure. From K values, we obtained the partial molar volume change and some other thermodynamic parameters. From the values of enthalpy, entropy and isoequilibrium temperature (649 K), we concluded that the dissociation of m-chloroanilinium ion mentioned above is controlled by enthalpy.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.201.1-201.1
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• 2003

Study of Acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors from medicinal plants, we found strong inhibitory activity of ACAT enzyme from rat liver microsome by the CHC1$_3$ extract of Piper longum. Bioactivity-guided fractionation led to the isolation of Guineensine (1), its structure was elucidated by spectroscopic (IR, UV, MS and NMR) means. It inhibited ACAT activity in a dose-dependent manner with IC$\sub$50/ values of 1.2 $\mu\textrm{g}$/ml on in vitro assay using rat liver microsome.

• 한국염색가공학회지
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• 제34권2호
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• pp.77-92
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• 2022

Natural colorants are regarded as substitutes for synthetic colorants in the fields of fiber dyeing, hair dyeing, cosmetic, and food industries. The use of natural colorants has been increased in view of global environment and sustainability. However, scientific approach to the production is required because the supply of natural colorants depends on the climate, soil, and cultivation methods. This brief review contains the advances in science and technology related to natural colorants including characterization, analysis, CIEL^*a^*b^* and Munsell color systems, and future prospects. For the characterization and the analysis of natural colorants, chromatography, some spectroscopic techniques (UV-Vis, FT-IR, NMR), mass spectrometry, and X-ray diffraction are generally used.

• 공업화학
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• 제34권2호
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• pp.131-136
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• 2023

가시광선 영역에서 빛을 흡수하는 고농도 시료의 농도를 색상 좌표 값을 이용해 측정하는 법을 개발하였다. 이성분계 고농도 시료와 색상 좌표 사이의 관계식을 실험식으로 구하고 Resazurin에서 Resorufin으로의 촉매 반응 속도를 평가하였다. 제시한 방법은 자외선가시광선분광법에서 비선형적으로 측정범위 한계를 넘어선 영역의 농도를 시료를 희석하지 않고 직접 측정할 수 있다.

• 천문학회보
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• 제45권1호
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• pp.69.4-70
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• 2020

Raman-scattered He II features are known to be present in several young planetary nebulae (PNe) including NGC 7027, NGC 6302, IC 5117 and NGC 6790. These features provide a new spectroscopic window to probe both thick neutral regions and far UV regions near Lyman series. We carry out photoionization model calculations using 'CLOUDY' to explore He II emission strengths dependent on the physical conditions of the central star. The emission nebula is treated as a simple spherical shell with uniform density. It is found that detectable Raman-scattered He II are obtained for T∗ ~ 105 K in the presence of a thick neutral component. We present mock spectra exhibiting Raman He II features based on the photoionization calculations and compare them with observed data. We discuss effective strategies for searching young PNe with Raman-scattered He II emissivities.

• 생약학회지
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• 제54권1호
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• pp.16-20
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• 2023

KSM-2690 B (1), a peptide-polyketide hybrid compound, was discovered from an actinomycete strain (CJD 1) isolated from Dong-Baek hill on Jeju Island, Republic of Korea. The chemical structure of 1 was identified by using NMR, MS, and UV spectroscopic analyses. Careful analysis of 1D and 2D NMR data revealed that KSM-2690 (1) has an oxazole ring, a β-lactone-γ-lactam spirocycle ring, and both triene and diene structures. KSM-2690 B (1) showed inhibitory activities against E. coli at 200 ㎍/mL.

• Natural Product Sciences
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• 제29권2호
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• pp.113-119
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• 2023

Descurainia sophia seeds methanol extract showed significant anti-influenza activity and we tried to isolate anti-influenza compounds from the D. sophia extract. D. sophia seeds were extracted with 80% methanol and fractionated with n-hexane, ethyl acetate, CHCl₃ and n-butanol. The anti-influenza activity of each fraction was assessed using sulforhodamine B (SRB) method in A549 cells, human-derived lung cancer cells. The ethyl acetate and CHCl₃ fractions showed the most potent anti-influenza activity. Seven compounds were isolated from CHCl₃ fraction and identified 1-decanol (1), 2-(3,4-dihydroxy-2-methylenebutoxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol (2), daucosterol (3), isorhamnetin (4), quercetin (5), sinapic acid (6), and helveticoside (7) by spectroscopic data such as UV, IR, ¹H-NMR, ¹³C-NMR and mass spectroscopy. Anti-influenza activities of isolated compounds were evaluated using SRB method in A549 cells. Compounds 3, 4 and 7 had significant anti-influenza activity in a dose-dependent manner.

• 분석과학
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• 제15권1호
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• pp.72-79
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• 2002

Di-(2-ethylhexyl)phthalate (DEHP) 가 가소제로 첨가되 있는 poly(vinylchloride) (PVC) 제품의 사용중에는 DEHP가 방출되어 나올 가능성이 있다. 이때 추출되는 DEHP의 정량적인 측정법에는 여러가지가 있으나 그 방법에 따라 용출량에 많은 차이가 발생하기 때문에 측정방법과 결과에 대한 비교분석은 시급한 과제라 할 수 있다. 이를 평가하기 위하여 PVC를 주원료로 하는 혈액백과 수액백에서의 DEHP 용출에 관한 연구를 기체 크로마토그래프와 분광광도계를 이용한 두 가지 방법으로 수행하였다. 5종류의 PVC 백을 실험 재료로 선택하여 $40{\times}10{\times}0.4mm$ 크기의 시편을 제조하고 이를 용출액에 담가 1시간동안 DEHP를 용출하였다. 기체 크로마토그래프로 DEHP 를 검출한 결과 시료에 따라 $23.2{\sim}70.9{\mu}g/mL$ 의 DEHP가 용출되는 것을 알 수 있었다. 반면 PVC백 안에 용출액을 주입하여 1시간 동안 DEHP를 용출시키고 분광 광도계를 이용하여 DEHP를 검출한 결과 $24.8{\sim}41.3{\mu}g/mL$의 DEHP가 용출되었다. 용출 조건과 실험방법에 따라 서로 다른 수치를 보임을 알 수 있었고 단위 시간 단위 면적 당 용출되는 DEHP의 양은 일정하다는 전제 하에 두 실험의 결과를 비교하고 환산하는 식을 구하여 적용한 결과 두 측정방법에서 얻어진 용출량이 거의 일치하였다.

• 한국안광학회지
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• 제13권1호
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• pp.37-42
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• 2008

목적: 플라스틱 렌즈에 착색이 가능한 하드코팅을 실시하고, 이 코팅의 분광 및 표면 특성을 평가하는데 있다. 방법: 코팅은 TEOS, MTMS과 GPTS를 이용한 졸-겔법으로 실시하였다. 코팅의 광학적 그리고 구조적 특성을 주사 전자현미경, 라만분광, 적외선분광 및 자외선/가시광선분광으로 조사하였다. 결과: 이 코팅의 착색성은 일반적인 하드코팅에 비해 2배 높았다. 착색 가능한 하드코팅이 적용된 렌즈의 부착성, 내마모성, 내온수성 및 내약품성은 우수하였다. 연필 경도는 5H였으며, 코팅의 표면은 매끄럽고 균일하였다. 결론: 플라스틱 렌즈에 이 코팅 시스템의 적용으로 착색이 가능한 단단하고 안정된 표면을 부여할 수 있었다.

• 천문학회보
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• 제37권1호
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• pp.31.2-31.2
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• 2012

We present the Yonsei Evolutionary Population Synthesis (YEPS) models for spectroscopic and photometric evolutions of simple and composite stellar populations. The models are based on the most up-to-date Yonsei-Yale stellar evolutionary tracks and BaSel 3.1 flux libraries, and provide integrated spectroscopic quantities of Lick/IDS system including high-order Balmer absorption-lines. Special care has been taken to incorporate the systematic variation of horizontal branch (HB) morphology as functions of metallicity, age, alpha-element mixture, and helium abundance of simple stellar populations. Our models for normal-helium stellar populations indicate that the realistic modeling of HB and alpha-element brings about 5 Gyr and 0.1 dex differences in age and metallicity estimations, respectively, compared to those without these effects. The HB effect does not depend on the specific choice of stellar libraries and alpha-element enhancements, and this effect is non-negligible even in the metal sensitive absorption indices, such as Mg2 and Mg b. Comparison of the models to observations reveals that the HB and alpha-element effects are critical in understanding otherwise inexplicable phenomena found in globular cluster systems in the Milky Way and nearby galaxies, including the observed bimodality of the line strengths of globular clusters in massive galaxies. In addition, we found that helium-enhanced stellar populations, which are the major sources of extreme HB stars, bring about increased FUV, NUV fluxes, and thus the model colors of those filters become extremely blue. Age dating based on the YEPS model with normal-helium stellar populations reveals that the evidence for 'downsizing' of elliptical galaxies is found not only in the local field but also in Coma cluster, and that the mean age of elliptical galaxies in Coma cluster is about 1.4 Gyr younger than the mean age of those in the local field. We also find that our models with helium-enhanced subpopulations can naturally reproduce the strong UV-upturns observed in giant elliptical galaxies assuming an age similar to that of old GCs in the Milky Way.