• 한국입자에어로졸학회지
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• 제17권4호
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• pp.91-106
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• 2021

Daily PM_2.5 was collected during summer period in 2020 in Gwangju to investigate its chemical and light absorption properties. In addition, real-time light absorption coefficients were observed using a dual-spot 7-wavelength aethalometer. During the study period, SO₄^2- was the most important contributor to PM_2.5, accounting for on average 33% (10-64%) of PM_2.5. The chemical form of SO₄^2- was appeared to be combination of 70% (NH₄)₂SO₄ and 30% NH₄HSO₄. Concentration-weighted trajectory (CWT) analysis indicated that SO₄^2- particles were dominated by local pollution, rather than regional transport from China. A combination of aethalometer-based and water-extracted brown carbon (BrC) absorption indicated that light absorption of BrC due to aerosol particles was 1.6 times higher than that due to water-soluble BrC, but the opposite result was found in absorption Ångström exponent (AAE) values. Lower AAE value by aerosol BrC particles was due to the light absorption of aerosol BrC by both water-soluble and insoluble organic aerosols. The BrC light absorption was also influenced by both primary sources (e.g., traffic and biomass burning emissions) and secondary organic aerosol formation. Finally the ATR-FTIR analysis confirmed the presence of NH₄⁺, C-H groups, SO₄^2-, and HSO₄^2-. The presence of HSO₄^2- supports the result of the estimated composition ratio of inorganic sulfate ((NH₄)₂SO₄) and bisulfate (NH₄HSO₄).

• Animal Bioscience
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• 제36권2호
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• pp.256-263
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• 2023

Objective: Feed molecular structures can affect its availability to gastrointestinal enzymes which impact its digestibility and absorption. The molecular spectroscopy-attenuated total reflectance Fourier transform infrared vibrational spectroscopy (ATR-FTIR) is an advanced technique that measures the absorbance of chemical functional groups on the infrared region so that we can identify and quantify molecules and functional groups in a feed. The program aimed to reveal the association of intrinsic molecular structure with nutrient supply to animals from canola feedstocks and co-products from bio-oil processing. The objective of this study was to characterize special intrinsic carbohydrate and protein-related molecular structure spectral profiles of feedstock and co-products (meal and pellets) from bio-oil processing from two source origins: Canada (CA) and China (CH). Methods: The samples of feedstock and co-products were obtained from five different companies in each country arranged by the Canola Council of Canada (CCC). The molecular structure spectral features were analyzed using advanced vibrational molecular spectroscopy-ATR-FTIR. The spectral features that accessed included: i) protein-related spectral features (Amide I, Amide II, α-helix, β-sheet, and their spectral intensity ratios), ii) carbohydrate-related spectral features (TC1, TC2, TC3, TC4, CEC, STC1, STC2, STC3, STC4, TC, and their spectral intensity ratios). Results: The results showed that significant differences were observed on all vibrationally spectral features related to total carbohydrates, structural carbohydrates, and cellulosic compounds (p<0.05), except spectral features of TC2 and STC1 (p>0.05) of co-products, where CH meals presented higher peaks of these structures than CA. Similarly, it was for the carbohydrate-related molecular structure of canola seeds where the difference between CA and CH occurred except for STC3 height, CEC and STC areas (p>0.05). The protein-related molecular structures were similar for the canola seeds from both countries. However, CH meals presented higher peaks of amide I, α-helix, and β-sheet heights, α-helix:β-sheet ratio, total amide and amide I areas (p<0.05). Conclusion: The principal component analysis was able to explain over 90% of the variabilities in the carbohydrate and protein structures although it was not able to separate the samples from the two countries, indicating feedstock and coproducts interrelationship between CH and CA.

• 폴리머
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• 제27권5호
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• pp.421-428
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• 2003

반응성 올리고머 및 메타아크릴레이트/SBS블렌드의 확산에 의해 제어되는 광중합 반응 특성을 ATR-FTR을 이용하여 고찰하였다. 광중합 속도는 반응 초기 단계에서는 자가 가속 현상을 보이며 반응 속도가 급격하게 증가하여 반응이 진행함에 따라 확산에 의한 반응 지연 현상이 관찰된다. 확산 제어항이 도입된 반응 기구 속도식으로 반응 속도를 해석한 결과 전체 반응 구간에서 실험 결과와 잘 일치하였다. SBS의 도입을 위해 사용된 반응성 용매인 N-비닐피롤리돈 (NVP)의 첨가에 의해서 최종 전환율에 이르는 시간은 거의 일정하였으나 전환율은 NVP의 높은 반응성으로 인하여 증가하는 경향을 보였다. 중합 반응 속도도 NVP 첨가에 의하여 증가하는 경향을 보였다. SBS의 첨가시 NVP-SBS의 함량이 10 phr까지는 동일한 전환율 거동을 보이나 NVP-SBS의 함량이 20 phr에서는 현저히 떨어지게 되는데 이는 NVP-SBS의 함량이 20 phr에서는 블렌드의 점도가 증가하여 반응에 영향을 주는 것으로 보인다. NVP-SBS의 함량이 증가함에 따라 중합 반응 속도는 점진적으로 감소함을 알 수 있었다. 메타아크릴레이트./SBS의 블렌드는 상온과 여러 높은 온도 범위에서 상분리가 관찰되지 않았으며 광중합 반응 후에도 투명한 준-IPN을 형성하여 성공적으로 필름 및 코팅에 적용할 수 있었다.

• Korean Chemical Engineering Research
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• 제48권5호
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• pp.568-573
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• 2010

본 연구에서는 polyester 섬유표면에 활성기를 부여하기 위한 전처리제로 isocyanate를 이용하여 농도에 따른 접착력을 평가하였다. 이 후 HNBR compound와 polyester fabric의 접착 시 접착력이 우수한 RFL 용액용 latex 선정 및 F/R mole ratio, F/R resin/latex 무게 비에 따른 실험을 진행하였다. 그 결과 전처리제의 농도가 7 wt%인 경우 가장 높은 접착력을 나타내었으며, RFL 용액용 latex로는 HNBR 컴파운드와 상용성이 높은 NBR latex가 우수한 결과를 나타내었고 F/R mole ratio, FR resin/latex 무게비가 각각 1/1, 20%일 때 가장 높은 접착력을 나타내었다. 또한, peel test와 FTIR 분석을 이용해 RF resin의 열처리 온도에 따른 접착강도와 spectra의 peak 변화를 평가해 본 결과 최적의 열처리 온도는 $200^{\circ}C$이었다.

• 폴리머
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• 제29권3호
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• pp.294-299
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• 2005

온도응답성 고분자인 PIPAAm을 포토마스크를 사용하여 전자빔조사에 의해 패턴상으로 세포배양용 폴리스티렌 접시표면에 그래프트하였다. 폴리스티렌 표면에의 PIPAAm의 그래프트는 AIR-FTIR과 ESCA에 의한 표면분석을 통해 확인하였다. 이러한 표면에 간실질세포를 $37^{circ}C$에서 배양하였고, 균일하게 간세포가 배양된 배양접시를 PIPAAm의 LCST 이하인 $20^{circ}C$로 배양온도를 낮추어 PIPAAm이 그래프트된 도메인에 접착된 간실질세포를 탈착시키고 배양접시를 다시 $37^{circ}C$로 올린 후 두 번째 세포인 혈관내피세포를 파종하여 PIPAAm이 그래프트된 도메인에만 선택적으로 접착시킴으로써 같은 평면상에서 간실질세포와 혈관내피세포를 공배양할 수 있게 되었다. 이러한 방법으로 생체외에서 간실질세포와 혈관내피세포를 장기간에 걸쳐 공배양할 수 있었다.

• 폴리머
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• 제34권6호
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• pp.511-516
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• 2010

탄소재료의 표면을 개질하고 이를 광전자 기능소자의 전극 재료로서 응용하는 가능성을 모색하기 위하여 탄소재료의 표면을 폴리(3-옥틸티오펜)으로 전기화학적 방법에 의하여 전착하는 것을 연구하였다. 전착의 기질로 사용되는 탄소재료의 형태로는 시판되는 탄소종이 및 탄소섬유를 택하였으며, 전기중합에 사용되는 단량체의 농도, 전해질의 농도, 인가전압의 변화, 순환전압전류법 사이클 회수를 달리하여 그 영향을 관찰하였다. 단량체의 농도와 전해질 농도의 증가, 인가전압의 증가, 순환전압전류법 사이클 회수의 증가에 따라 탄소종이와 탄소섬유에 중합된 폴리(3-옥틸티오펜)의 양이 증가함을 관찰하였으며, 중합속도에 미치는 영향을 각각의 변수에 대한 지수를 측정해서 분석하였다. 폴리(3-옥틸티오펜)이 중합된 탄소재료의 표면은 주사전자현미경을 통해 관찰하였고 그 구조를 FTIR-ATR로 분석하였다.

• Elastomers and Composites
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• 제48권1호
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• pp.46-54
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• 2013

본 연구에서는 저온유화중합을 통해 벤질메타아크릴레이트 (benzyl methacrylate, BzMA) 를 third monomer 로 사용하여 styrene-butadiene-benzyl methacrylate copolymer (BzMA-SBR) 를 합성하였다. 수산화나트륨 (NaOH) 을 이용하여 가수분해반응을 통해 BzMA 의 벤질 그룹을 deprotection 시켜 carboxylated styrene butadiene rubber (XSBR) 로 만든 후, Na-XSBR 아이오노머를 제조하였다. 중합 시 BzMA 의 투입량을 달리하여 XSBR의 카르복실기 (carboxyl group) 함량을 다양하게 조절하였다. FTIR (ATR), $^1H$ NMR, DSC 를 이용하여 합성된 BzMA-SBR, Na-XSBR 아이오노머의 구조와 특성을 분석하였다.

• Animal Bioscience
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• 제37권8호
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• pp.1398-1407
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• 2024

Objective: The objective of this study was to determine internal structure spectral profile of by-products from coffee processing that were affected by added-microorganism fermentation duration in relation to truly absorbed feed nutrient supply in ruminant system. Methods: The by-products from coffee processing were fermented using commercial fermentation product, consisting of various microorganisms: for 0 (control), 7, 14, 21, and 28 days. In this study, carbohydrate-related spectral profiles of coffee by-products were correlated with their chemical and nutritional properties (chemical composition, total digestible nutrient, bioenergy values, carbohydrate sub-fractions and predicted degradation and digestion parameters as well as milk value of feed). The vibrational spectra of coffee by-products samples after fermentation for 0 (control), 7, 14, 21, and 28 days were determined using a JASCO FT/IR-4200 spectroscopy coupled with accessory of attenuated total reflectance (ATR). The molecular spectral analyses with univariate approach were conducted with the OMNIC 7.3 software. Results: Molecular spectral analysis parameters in fermented and non-fermented by-products from coffee processing included structural carbohydrate, cellulosic compounds, non-structural carbohydrates, lignin compound, CH-bending, structural carbohydrate peak1, structural carbohydrate peak2, structural carbohydrate peak3, hemicellulosic compound, non-structural carbohydrate peak1, non-structural carbohydrate peak2, non-structural carbohydrate peak3. The study results show that added-microorganism fermentation induced chemical and nutritional changes of coffee by-products including carbohydrate chemical composition profiles, bioenergy value, feed milk value, carbohydrate subfractions, estimated degradable and undegradable fractions in the rumen, and intestinal digested nutrient supply in ruminant system. Conclusion: In conclusion, carbohydrate nutrition value changes by added-microorganism fermentation duration were in an agreement with the change of their spectral profile in the coffee by-products. The studies show that the vibrational ATR-FT/IR spectroscopic technique could be applied as a rapid analytical tool to evaluate fermented by-products and connect with truly digestible carbohydrate supply in ruminant system.

• 한국입자에어로졸학회지
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• 제9권4호
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• pp.201-208
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• 2013

Copper (II) and Nickel (II) mimic complexes of enzyme carbonic anhydrase were evaluated under ambient condition for carbon dioxide capture and conversion process. The synthesized complexes were characterized by ATR-FTIR and UV-DR spectroscopy. It was found that all the complexes have biomimetic activity towards $CO_2$ using para-nitrophenyl acetate (p-NPA) hydrolysis as the model reaction. Interestingly, the proper geometry obtained by the restricted orientation of tripodal N atoms in Cu (II) complex of 2,6-bis(2-benzimidazolyl) pyridine showed the highest activity (1.14 au) compared to others. The $CO_2$ bio-mineralization to $CaCO_3$ was carried out via in-vitro crystallization approach. Results indicate that the biomimetic complexes have a role in determining $CaCO_3$ morphology. The present observations establish a qualitative insight for the design of improved small-molecule catalysts for carbon capture.

• Journal of the Korean Wood Science and Technology
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• 제48권2호
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• pp.231-244
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• 2020

As a way of finding value-added materials from waste medium density fiberboard (MDF), this study characterized cellulose nanocrystals (CNCs) isolated by ammonium persulfate (APS) oxidation using recycled MDF fibers. Chemical composition of the recycled MDF fibers was done to quantify α-cellulose, hemicellulose, lignin, nitrogen, ash and extractives. The APS oxidation was performed at 60 ℃ for 16 h, followed by ultrasonication, which resulted in a CNC yield of 11%. Transmission electron microscope images showed that rod-like CNCs had an average length and diameter of 167±47 nm and 8.24±2.28 nm, respectively, which gave an aspect ratio of about 20. The conductometric titration of aqueous CNCs suspension resulted in a carboxyl content of 0.24 mmol/g and the degree of oxidation was 0.04. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy clearly showed the presence of carboxyl group on the CNCs prepared by the APS oxidation. The change of pH of the aqueous CNC suspension from 4 to 7 converted the carboxyl group to sodium carboxylate group. These results showed that the APS oxidation was facile and CNCs had a one-step preparation method, and thus suggested an optimization of the oxidation condition in future.