• 대한화학회지
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• 제55권1호
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• pp.19-27
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• 2011

2-(Benzothiazol-2-yl)-N'-(2,5-dihydroxybenzylidene)acetohydrazide 에대한새로운일련의 Mn(II), Ni(II), Co(II), Cu(II) 및 Zn(II) 착물을 합성하여 그 특성을 원소분석, IR, UV-vis, $^1H$-NMR, 질량분석, ESR, 자기수자율 및 몰 전기전도도 측정에 의하여 조사하였다. 이들 착물의 기하구조가 사각평면 또는 팔면체임을 분광학적 데이터 및 자기적 측정으로부터 알았다. 이 리간드와 해당착물의 세균에(Aspergillus nigar 및 Fusarium oxysporium) 대한생물학적활성을 조사하였다. 그 결과, 금속착물들은 리간드 및 금속이온 모두에 비해 더 큰 활성을 나타내었다.

• 대한화학회지
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• 제47권1호
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• pp.38-42
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• 2003

신농약 개발을 목적으로 isosterism 이론을 근거로 하여 선도화합물, 2-imino-1,3-thiazoline의 분자 수정을 통하여 분자내에 1,3-thiazole과 urea기가 포함된 새로운 화합물 2를 디자인하였다. N-Methylthiourea 5와 bromoacetonitrile을 에탄올 용액 중에서 반응시켜 위치 선택적으로 생성된 2,4-diimino-1,3-thiazole 4를 phenylisocyanate 유도체와 반응하여 화합물 2의 tautomer인 7을 얻었고 이것의 구조를 여러 가지 스펙트럼($^1H$ NMR, $^{13}C$ NMR, FT-IR, HRMS)과 X-ray 결정 데이터로부터 확인하였다. 화합물 7의 구조이성질체 8은 열역학적으로 불안정한 중간체 2,4-diimino-1,3-thiazole 6을 통하여 생성되었다.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1801-1808
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• 2006

The interaction between whey carrier protein $\beta$-lactoglobulin type A and B (BLG-A and -B) and 2,2'-bipyridin n-hexyl dithiocarbamato Pd(II) nitrate (BPHDC-Pd(II)), a new heavy metal complex designed for anticancer property, was investigated by fluorescence spectroscopy combined with chemometry and circular dichroism (CD) techniques. A strong fluorescence quenching reaction of BPHDC-Pd(II) to BLG-A and -B was observed. Hence, BPHDC-Pd(II) complex can be bound to both BLG-A and -B, and quench the fluorescence spectra of the proteins. The quenching constant was determined using the modified Stern-Volmer equation. The binding parameters were evaluated by fluorescence quenching method. The results of binding study provided evidences presence of two and three sets of binding sites on the BLG-B and -A, respectively, for BPHDC-Pd(II) complex. Using fluorescence spectroscopy and chemometry, the ability of BLG-A and -B to form an intermediate upon interaction with BPHDC-Pd(II) complex was assessed. CD studies displayed that under influence of different concentrations of BPHDC-Pd(II) complex, the regular secondary structure of BLG-B had no significant changes, whereas for BLG-A a transition from $\alpha$-helix to $\beta$-structure was appeared. The results for both of BLG-A and -B displayed that BPHDC-Pd(II) complex can induce a conformational transition from the native form to an intermediate state with a slightly opened conformation, which is detectable with chemometry analyses.

• 한국진공학회지
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• 제6권3호
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• pp.242-248
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• 1997

기존의 다공질 실리콘 제작 방법인 chemical etching 방법을 병행하면서 새로운 제 작 방법으로서 dry etching 기술을 적용하여 다공질 실리콘을 제작하였다. 또한, 비교를 위 해 E-beam lithography 기술로 실리콘 구조물을 제작하였는데 이 경우 기술상 문제로 약 0.3$\mu\textrm{m}$의 직경을 가진 구조물이 최소의 크기였다. 따라서 새로운 방법으로 4인치 wafer위에 mask 역할을 해주는 다이아몬드 분말을 spin coater로 입힌 후 Reactive Ion Etching(RIE) 방법으로 미세구조의 다공질 실리콘을 제작하였다. 다양한 조건으로 제작된 sample들의 morphology를 SEM과 AFM 등을 이용하여 분석하였고 이 morphology에 대응하는 PL스펙 트럼을 측정하였다. 그 결과, 다이아몬드 분말을 이용한 dry etching방법으로 제작된 다공질 실리콘의 PL peak의 위치가 chemical etching 방법의 다공질 실리콘의 PL peak 위치인 760nm에 비해 높은 에너지인 590nm로 나타났다.

• 한국수소및신에너지학회논문집
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• 제21권5호
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• pp.375-382
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• 2010

A layered perovskite photocatalysts, $SrBi_2Nb_2O_9$ (SBN), was synthesized by the conventional solid-state reaction method and characterized by X-ray diffraction (XRD) and UV-visble spectrophotometry. The results showed that the structure of $SrBi_2Nb_2O_9$ is orthorhombic. Diffuse reflectance spectra for calcined and attrition-milled SBN showed the main absorption edges were less 400 nm, that is ultraviolet region. SBN under micron-sized powder was deposited on the $Al_2O_3$ by room temperature powder spray in vacuum process, so called aerosol deposition (AD), and nano-grained $SrBi_2Nb_2O_9$ photocatalytic thick film was fabricated. AD-deposited SBN thick films were characterized by XRD, scanning electron microscopy (SEM) and UV-visable spectrophotometry, Moreover, it was found that several nano-sized SBN film by AD process can improve the photocatalytic activity under visable reflectance.

• 천문학회보
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• 제44권1호
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• pp.38.2-38.2
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• 2019

S0 galaxies are mostly known to be formed in dense environments from spiral progenitors. Recently, however, a new formation scenario has been suggested that field S0s can be formed from elliptical progenitors. The Sombrero galaxy (M104, NGC 4594) is a massive disk galaxy located in the field environment, and its morphological type has been controversial from Sa to E. Thus, it is an ideal target to test the new scenario. We trace the giant halo of M104 with globular clusters to test this scenario. From the wide images obtained with CFHT/MegaCam, we find a large number of globular clusters in this galaxy. We also confirm their membership by measuring the radial velocities from the spectra obtained with MMT/Hectospec. The color distribution of these globular clusters is bimodal, and blue (metal-poor) globular clusters are more spatially widely spread than red (metal-rich) globular clusters. This indicates that M104 hosts a giant metal-poor halo as well as an inner metal-rich halo. Combining this result with the fact that M104 is unusually massive and brighter than other spiral galaxies, we infer that M104 was indeed a massive elliptical galaxy that had formed a metal-rich halo by gas-rich mergers and a metal-poor halo by gas-poor mergers. In addition, we find young star clusters around the disk of M104, which shows that the disk formed after the spheroidal halos had formed. In conclusion, we suggest that M104 was originally a massive elliptical galaxy and was transformed to a lenticular galaxy by acquiring its disk later.

• 천문학회지
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• 제54권5호
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• pp.139-155
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• 2021

We present an updated version of the multilayer spectral inversion (MLSI) recently proposed as a technique to infer the physical parameters of plasmas in the solar chromosphere from a strong absorption line. In the original MLSI, the absorption profile was constant over each layer of the chromosphere, whereas the source function was allowed to vary with optical depth. In our updated MLSI, the absorption profile is allowed to vary with optical depth in each layer and kept continuous at the interface of two adjacent layers. We also propose a new set of physical requirements for the parameters useful in the constrained model fitting. We apply this updated MLSI to two sets of Hα and Ca II line spectral data taken by the Fast Imaging Solar Spectrograph (FISS) from a quiet region and an active region, respectively. We find that the new version of the MLSI satisfactorily fits most of the observed line profiles of various features, including a network feature, an internetwork feature, a mottle feature in a quiet region, and a plage feature, a superpenumbral fibril, an umbral feature, and a fast downflow feature in an active region. The MLSI can also yield physically reasonable estimates of hydrogen temperature and nonthermal speed as well as Doppler velocities at different atmospheric levels. We conclude that the MLSI is a very useful tool to analyze the Hα line and the Ca II 8542 line spectral daya, and will promote the investigation of physical processes occurring in the solar photosphere and chromosphere.

• 천문학회보
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• 제44권2호
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• pp.64.1-64.1
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• 2019

The first high-resolution spectroscopic and new multiband photometric observations of the semi-detached Algol type binary XZ CMi were performed at the Bohyunsan Optical Astronomy Observatory (BOAO) and the Sobaeksan Optical Astronomy Observatory (SOAO), respectively. A total of 34 spectra were obtained using the 1.8 m reflector of the BOAO equipped with the Bohyunsan Optical Echelle Spectrograph to construct the radial velocity (RV) curves of the eclipsing pair. New BVRI photometric light curves were also covered by using the SOAO 61cm reflector and a CCD camera. A detailed analysis of all eclipse timings shows that the orbital period of XZ CMi has varied in an upward parabolic variation superposed on a sinusoidal oscillation with a period of 38.0 yr and a semi-amplitude of 0.0071 days. From the spectral analysis, the effective temperature and the projected rotational velocity of the primary component were determined to be T_eff,1 = 7387±161 K and v₁sini = 122±6 km s^-1, respectively. Our simultaneous synthesis of the double-lined RV and BVRI light curves gives the reliable system parameters of XZ CMi with a mass ratio (q) of 0.314, an orbital inclination (i) of 81.9 deg and a large temperature difference (∆T) of 2481 K. The individual masses and radii of both components are M₁ = 1.91±0.08M_⊙, M₂ = 0.60±0.02M_⊙, R₁ = 1.60±0.02R_⊙, R₂ = 1.13±0.02R_⊙, respectively. Although the primary component is located inside the δ Sct and γ Dor instability strips, no evidence of pulsation in the system was detected. The possible evolutionary status of XZ CMi is discussed.

• 한국응용과학기술학회지
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• 제31권4호
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• pp.595-601
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• 2014

NATM의 미세 구조는 SEM, FT-IR, 인장특성, 그리고 [NCO]/[OH]의 mole %, 입도분석에 의해 측정하였다. 친환경적인 NATM에 관한 관심이 고조됨에 따라 스테인레스 등의 금속코팅에 더욱더 중요한 무용제 도료의 발전을 이끈다. 우리는 스테인레스 스틸의 부식을 방지할 수 있는 NATM(New Austria Tunnel Method)의 수지를 합성하였다. 폴리우레탄과 에폭시로 합성한 혼성 수지는 일반적 NATM 수지와 도료와 비교하여 강도와 내구력이 매우 양호하다. 혼성수지는 폴리올, 에폭시, MDI, 실리콘 계면활성제, 촉매, 가교제, 충전제로 구성된다. 충전제인 fume silica는 경화속도를 가속시킬 뿐만 아니라 열적 장벽으로 물성이 우수함을 나타냈다. NATM 수지의 기계적 특성은 [NCO]/[OH]의 mole%와 fume silica가 증가함에 따라 강도가 증가하였다. 결론적으로 가교제와 fume silica가 함유된 혼성수지의 미세구조는 스테인레스 스틸같은 금속물질의 열경화코팅을 위한 좋은 물질이다.

• Near Infrared Analysis
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• 제2권1호
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• pp.59-66
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• 2001

Nowadays, medical diagnostics is efficiently supported by clinical chemistry and near infrared spectroscopy is becoming a new dimension, which has shown high potential to provide valuable information for diagnosis. The investigation was carried out to study the influence of mammary gland inflammation, called mastitis, on cow´s milk spectra and milk composition measured by near infrared spectroscopy (NIRS). Milk somatic cell counts (SCC) in milk were used as a measure of mammary gland inflammation. Naturally occurred variations with milk composition within lactation and in the process of milking were included in the experimental design of this study. Time series of unhomogenized, raw milk spectral data were collected from 3 cow along morning and evening milking, for 5 consecutive months, within their second lactation. In the time of the trial, the investigated cows had periods with mammary gland inflammation. Transmittance spectra of 258 milk samples were obtained by NIRSystem 6500 spectrophotometer in 1100-2400 nm region. Calibration equations for the examined milk components were developed by PLS regression using 3 different sets of samples: samples with low somatic cell count (SCC), samples with high SCC and combined data set. The NIR calibration and prediction of individual cow´s milk fat, protein, and lactose were highly influenced by the presence of mil samples from animals with mammary gland inflammation in the data set. The best accuracy of prediction (i.e. the lower SEP and the higher correlation coefficient) for fat, protein and lactose was obtained for equations, developed when using only “healthy” samples, with low SCC. The standard error of prediction increased and correlation coefficient decreased significantly when equations for low SCC milk were used to predict examined components in “mastitis” samples with high SCC, and vice versa. Combined data set that included samples from healthy and mastitis animals could be used to build up regression models for screening. Further use of separate model for healthy samples improved milk composition measurement. Regression vectors for NIR mild protein measurement obtained for “healthy” and “mastitic” group were compared and revealed differences in 1390-1450 nm, 1500-1740 nm and 1900-2200 nm regions and thus illustrated post-secretory breakdown of milk proteins by hydrolytic enzymes that occurred with mastitis. For the first time it has been found that monitoring the spectral differences in water bands at 1440 nm and 1912 nm could provide valuable information for inflammation diagnosis.