• 암석학회지
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• 제22권2호
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• pp.83-115
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• 2013

피션트랙(fission-track: FT) 연대측정 초기단계의 부적합한 연대보정법에 기인한 오류 원인을 정밀진단하고, 중복시료에 의한 재실험과 제타보정법에 의해 최초 보고된 피션트랙(FT) 연대를 재정의한다. 재검토된 FT 저콘연대는 기반암인 유천층군 유문암질-데사이트질응회암의 생성연대를 후기 백악기부터 고제3기 초($78{\pm}4$ Ma부터 $65{\pm}2$ Ma)로 재정의하며, 곡강동유문암질응회암을 전기 에오세($52.1{\pm}2.3$ Ma) 산물로 정의한다. 전기 마이오세 화산암의 경우, 효동리화산암류 상부 데사이트질응회암($21.6{\pm}1.4$ Ma)과 범곡리화산암류 최상부 데사이트 용암($21.3{\pm}2.0$ Ma)의 FT 저콘연대는 각각 어일분지 남부와 와읍분지 중앙부의 상부 범곡리층군의 연대층서를, 그리고 금오리데사이트질응회암($19.8{\pm}1.6$ Ma)의 FT 저콘연대는 장기분지 내 후기 데사이트질 화산활동 시기를 정의한다. 데사이트질암의 FT 저콘연대와 현무암질-안산암질암의 기존 연대자료(대부분 K-Ar 전암, 일부 Ar-Ar)를 기반으로 하여, 한국 동남부의 마이오세 분지의 화산암과 기반암의 층서대비에 길잡이가 될 수 있는 참고연대를 설정 제안한다. 관계화산암의 연대에 기반하여 분지충전 퇴적지층의 퇴적시기도 추정한다. 제안된 참고연대는 마이오세 분지의 복잡한 분지구조와 비교적 짧은 연대범위에도 불구하고 지질층서에 잘 부합된다. 범곡리층군은 어일-와읍분지에서 장기층군보다 하위인 것이 확실하나, 장기분지의 전기 장기층군과 상당부분 중첩 병립되므로, 두 층군을 획일적으로 선후관계로 정의할 수는 없다. 장기분지에서 장기층군 하나로 묶여있는 일련의 지층군은 약 20 Ma를 기준으로 전기(23-20 Ma)의 안산암질-데사이트질암과 후기(20-18 Ma)의 현무암질암으로 뚜렷하게 구분된다.

• 한국안전학회지
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• 제12권4호
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• pp.180-190
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• 1997

A new method in the fault tree analysis (FTA) for the reliability calculation is suggested. Two steps are necessary in traditional method in evaluation of the occurrence probability of top event in fault tree (FT). The first step is to find the minimal outsets, and the second one is to substitute the result into the poincare equation. In order to reduce the enormous computing time of this method, lots of rapid algorithms have been developed. Almost of all achievements were, however, based on the partial structural properties of FT. In this paper, the FT is transformed to a non-linear graph G which has the same minimal outsets of original n, and then the reliability is calculated using the domination theory. In this new method, the required number of equation terms are at most $2^n$ (n is node number of graph G), while $2^m$-1 (m is the number of minimal cutsets) calculation terms are required in the poincare equation in traditional method. Since m>>n in general. our new method reduces the calculation time significantly.

• Journal of Applied Biological Chemistry
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• 제49권1호
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• pp.8-10
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• 2006

Compositions of methionine-metal chelates have been investigated by FT-IR and XRD studies to elucidate their molecular structures. It was concluded that Copamin and Zincamin contain a high percentage of crystalline products, presumably 2:1 Methionine-Cu or Zn complexes. On the contrary, FT-IR and XRD spectra of Ferramin didn't show any characteristics of the chelate and it was concluded to contain major components of starting $FeSO_4$ and methionine without chelation.

• 한국축산식품학회지
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• 제42권2호
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• pp.341-349
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• 2022

The objective of this study was to examine the effect of temperature abuse prior to cold storage on changes in quality and metabolites of frozen/thawed beef loin. The aerobic packaged samples were assigned to three groups: refrigeration (4℃) (CR); freezing (-18℃ for 6 d) and thawing (20±1℃ for 1 d), followed by refrigeration (4℃) (FT); temperature abuse (20℃ for 6 h) prior to freezing (-18℃ for 6 d) and thawing (20±1℃ for 1 d), followed by refrigeration (4℃) (AFT). FT and AFT resulted in higher volatile basic nitrogen (VBN) values than CR (p<0.05), and these values rapidly increased in the final 15 d. Cooking loss decreased significantly with an increase in the storage period (p<0.05). In addition, cooking loss was lower in the FT and AFT groups than in the CR owing to water loss after storage (p<0.05). A scanning electron microscope (SEM) revealed that frozen/thawed beef samples were influenced by temperature abuse in the structure of the fiber at 15 d. Metabolomic analysis showed differences among CR, FT, and AFT from partial least square discriminant analysis (PLS-DA) based on proton nuclear magnetic resonance (¹H NMR) profiling. The treatments differed slightly, with higher FT than AFT values in several metabolites (phenylalanine, isoleucine, valine, betaine, and tyrosine). Overall, temperature abuse prior to freezing and during thawing of beef loin resulted in accelerated quality changes.

• 펄프종이기술
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• 제31권4호
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• pp.16-22
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• 1999

The quantitative analysis of SB latex contents in coating color and coated paper was investigated with FT/Raman spectroscopy. From the measured FT/IR and FT/Ramon spectra, the peaks of coating color were compared with those of each compoents . Calibration curves were obtained by the area of latex peaks and PLS method of QuantIR program. The relation of predicted values in PLS method and actual values in coating mixtures and coating layer was examined. The components of coating layer in coated paper were investigated by EDS , X-mapping and SEM, The contents of latex in z-direction were calculated in the coating layer of unknown coated paper. The latex concentration measurements of Top layer and Pre layer in double coated paper show that each layer has different value. In single coated paper, it is clear that the latex concentration is highest at the surface and decreases with an increase of depth. From those results it is indicated that the latex migrates to the coated surface. The result of this study may be applied to the binder migration study and the quality control in paper mill.

• 공업화학
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• 제7권2호
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• pp.356-361
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• 1996

반응성 첨가제로 HQ와 PGE를 합성시킨 HQ-PGE를 사용하여, DGEBA/MDA계의 경화반응이 일어날 때의 속도론을 DSC와 FT-IR을 이용하여 조사하였다. 그리고, Kissinger equation과 Arrhenius equation을 이용하여 활성화 에너지와 pre-exponential factor 값을 구하였다. 계의 활성화 에너지는 HQ-PGE가 첨가되었을 때 감소하였다. 합성 HQ-PGE가 5 phr 첨가되었을 때, DGEBA/MDA계의 활성화 에너지는 FT-IR로 측정하였을 때 7.8 kcal/mol, DSC로 측정하였을 때에 11.3 kcal/mol을 나타내었다. 이 값은 HQ-PGE가 첨가되지 않은 경우보다 각각 30%, 9% 감소된 값이었다. 이 결과들을 통해서 반응성 첨가제로 사용된 HQ-PGE는 본 계에서 촉매의 역할을 함을 알 수 있었다.

• Mass Spectrometry Letters
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• 제9권3호
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• pp.81-85
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• 2018

In this study, the chemical composition of bacterial melanin isolated from the Streptomyces glaucescens strain was elucidated by ultra-high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Ultra-high-resolution mass profiles of the microbial melanin product were acquired using a 15 Tesla FT-ICR mass spectrometer in positive and negative ion modes via electrospray ionization to obtain more complete descriptions of the molecular compositions of melanin-derived organic constituents. A mass resolving power of 500,000 (at m/z 400) was achieved for all spectra while collecting 400 scans per sample with a 4 M transient. The results of this analysis revealed that the melanin pigment isolated from S. glaucescens predominantly exhibits CHON and CHO species, which belong to the proteins class of compounds, with the mean C/O and C/N ratios of 4.3 and 13.1, thus suggesting that the melanin could be eumelanin. This analytical approach could be utilized to investigate the molecular compositions of a variety of natural or synthetic melanins. The compositional features of melanins are important for understanding their formation mechanisms and physico-chemical properties.

• 한국세라믹학회지
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• 제51권4호
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• pp.350-356
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• 2014

Recently, Chemical Vapor Deposition (CVD) synthetic diamonds have been introduced to the jewelry gem market, as CVD technology has been making considerable advances. Unfortunately, CVD diamonds are not distinguishable from natural diamonds when using the conventional gemological characterization method. Therefore, we need to develop a new identification method that is non-destructive, fast, and inexpensive. In our study, we employed optical microscopy and spectroscopy techniques, including Fourier transform infra-red (FT-IR), UV-VIS-NIR, photoluminescence (PL), micro Raman, and cathodoluminescent (CL) spectroscopy, to determine the differences between a natural diamond (0.30 cts) and a CVD diamond (0.43 cts). The identification of a CVD diamond was difficult when using standard gemological techniques, UV-VIS-NIR, or micro-Raman spectroscopy. However, a CVD diamond could be identified using a FT-IR by the Type II peaks. In addition, we identified a CVD diamond conclusively with the uneven UV fluorescent local bands, additional satellite PL peaks, longer phosphorescence life time, and uneven streaks in the CL images. Our results suggest that using FT-IR combined with UV fluorescent images, PL, and CL analysis might be an appropriate method for identifying CVD diamonds.

• 공업화학
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• 제19권4호
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• pp.376-381
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• 2008

화력 발전소에서 발생되는 질소산화물(NOx)을 제거하기 위하여 환원제로써 $NH_3$를 이용한 선택적 촉매환원법(Selective Catalytic Reduction: SCR)에 사용되는 $V/TiO_2$ 촉매의 활성저하에 관하여 연구하였다. 장기간 배기가스에 노출된 촉매(Used-cat)의 활성과 비표면적이 상당히 감소되었다. 촉매의 특성분석은 XRD, FT-IR, FE-SEM, IC/ICP 등을 이용하여 수행하였다. 분석결과 배기가스에 노출되지 않은 사용 전 촉매(Fresh-cat)와 사용 후 촉매(Used-cat) 두 촉매 모두 $TiO_2$의 결정구조는 변하지 않았다. 그러나, FT-IR, FE-SEM, IC/ICP에 의한 촉매의 특성분석결과 사용 후 촉매(Used-cat) 표면에 $(NH_4)HSO_4$가 침적이 되었음을 확인하였다. 또한, $SO_2$에 대한 내구성이 우수한 촉매일수록 표면에 형성되는 황산염($SO_4^{-2}$)이 적게 형성됨을 확인할 수 있었다.

• Journal of Ginseng Research
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• 제42권3호
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• pp.270-276
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• 2018

Background: Notoginsenoside Ft1 is a promising potential candidate for cardiovascular and cancer disease therapy owing to its positive pharmacological activities. However, the yield of Ft1 is ultralow utilizing reported methods. Herein, an acid hydrolyzing strategy was implemented in the acquirement of rare notoginsenoside Ft1. Methods: Chemical profiles were identified by ultraperformance liquid chromatography coupled with quadruple-time-of-flight and electrospray ionization mass spectrometry (UPLC-Q/TOF-ESI-MS). The acid hydrolyzing dynamic changes of chemical compositions and the possible transformation pathways of saponins were monitored by ultrahigh-performance LC coupled with tandem MS (UHPLC-MS/ MS). Results and conclusion: Notoginsenoside Ft1 was epimerized from notoginsenoside ST4, which was generated through cleaving the carbohydrate side chains at C-20 of notoginsenosides Fa and Fc, and vinaginsenoside R7, and further converted to other compounds via hydroxylation at C-25 or hydrolysis of the carbohydrate side chains at C-3 under the acid conditions. High temperature contributed to the hydroxylation reaction at C-25 and 25% acetic acid concentration was conducive to the preparation of notoginsenoside Ft1. C-20 epimers of notoginsenoside Ft1 and ST4 were successfully separated utilizing solvent method of acetic acid solution. The theoretical preparation yield rate of notoginsenoside Ft1 was about 1.8%, which would be beneficial to further study on its bioactivities and clinical application.