• Applied Biological Chemistry
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• 제35권2호
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• pp.92-98
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• 1992

묵의 원료로 사용되는 동부, 녹두, 도토리와 묵의 원료로 사용되지 않는 팥, 밀, 고구마로부터 전분을 분리하여 이화학적 특성과 분자구조적 특성을 비교하였다. 아밀로오스 함량은 두류인 동부, 녹두, 팥에서 높았고, 밀, 도토리, 고구마의 순으로 낮았다. 아밀로그램에 의한 호화양상은 동부와 녹두 전분이 유사하였고, 팥 전분의 냉각점도와 고구마 전분의 최고점도가 높았으며, 밀 전분은 전반적으로 점도가 낮았다. 아밀로오스의 분자량 분포는 묵 형성 전분이 팥이나 밀보다 $5{\times}10^5$ 이상 큰 분자량의 것들이 많았으며, 예외로 고구마는 아밀로오스의 분자크기는 크나 아밀로오스 함량이 작아 묵을 형성하기 어려운 것으로 생각된다. 아밀로펙틴의 평균사슬길이는 $23{\sim}27$포도당 단위로 시료간에 큰 차이를 보이지 않았으나 팥이 길었고 동부와 도토리가 짧았다. 아밀로펙틴의 $peak\;II(DP\;35{\sim}55)$에 대한 $peak\;III(DP\;10{\sim}20)$의 비율은 동부, 녹두, 도토리가 팥, 고구마, 밀 아밀로펙틴보다 컸다.

• 한국표면공학회지
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• 제49권6호
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• pp.539-548
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• 2016

The non-noble 1D nanofibers(NFs) prepared by electrospinning and calcination method were used as oxygen evolution reaction (OER) electrocatalyst for water electrolysis. The electrospinning process and rate of solution composition was optimized to prepare uniform and non-beaded PVP polymer electrospun NFs. The diameter and morphology of PVP NFs changed in accordance with the viscosity and ion conductivity. The clean metal precursor contained electrospun fibers were synthesized via the optimized electrospinning process and solution composition. The calcined $CuCo_2O_4$ NFs catalyst showed higher activity and long-term cycle stability for OER compared with other $Co_3O_4$, $NiCo_2O$ NF catalysts. Furthermore, the $CuCo_2O_4$ NFs maintained the OER activity during long-term cycle test compared with commercial $CuCo_2O_4$ nanoparticle catalyst due to unique physicochemical and electrochemical properties by1D nanostructure.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.72-72
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• 2018

The root of Angelica gigas Nakai (AGN) is used as a traditional herbal medicine in Korea for the treatment of many diseases. However, a major challenge associated with the usage of the active compounds from AGN is their poor water solubility. Therefore, this work aimed to enhance the solubility of active compounds by a chemical (viz. surfactant) and physical (hot melt extrusion) crosslinking method (CPC). Infrared Fourier transform spectroscopy (FT-IR) revealed multiple peaks in extrudate solids representing new functional groups including carboxylic acid, alkynes and benzene derivatives. Differential scanning calorimetry (DSC) analysis of the extrudate showed lower glass transition temperature (Tg) and lower enthalpy (${\Delta}H$) (Tg: $43^{\circ}C$; ${\Delta}H$: <6 (J/g)) compared to the non-extrudate (Tg $68.5^{\circ}C$; ${\Delta}H$: 123.2) formulations. X-ray powder diffraction (XRD) analysis revealed amorphization of crystal materials in extrudate solid. In addition, nanonization, enhanced solubility and higher extraction of phenolic compounds were achieved in the extrudate solid. Among the different extrudates, acetic acid- and Span 80-mediated formulations showed superior extractions. We conclude that the CPC method successfully enhanced the production of amorphous nano dispersions from extrudate solid formulations.

• 한국환경과학회지
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• 제6권3호
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• pp.249-258
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• 1997

Mercury- and cadmium-resistant bacteria were Isolated from an Industrial complex wastewater of Taejon area. All of them were motile, gram negative rods. In the results of physicochemical test and VITEK card test. HM1 was Identified with Achetobacter cd- coaceucus, CM3 was Identified 65 Commonas acidovorns, HM2, HM3, CMI , and CM4 were Pseudomonas sp., but HM4 and CM2 were unidenteed. They were tested for subceptlbility to 14 heavy metals. Mercury-resistant bacteria(HM1, HM2, HM3, and HM4) were sensitive to low concentration(100~400ppm) of $Cd^{2+}$, $Co^{2+}$. $Zn^{2+}$, and Ni2+, while cadmium-resistant bacteria(CM1, CM2, CM3, and CM4) showed resistance up to the high concentration(600~ 1, 200ppm) of these metal loons. As a result of resistance spectrum test of mercury-resistant bacteria, HM1 was broad-spectrum strain, HM2. HM3, and HM4 were narrow-spectrum stratas. Transmission electron microscopic examination of cell wall of HM1 culture grown with and without 100ppm of $HgCl_2$ showed remarkably merphological abnormalities. In the result of atomic absorption spectrometric analysis of cadmium-resistant bacteria grown at 200ppm of $CdCl_2$ for 6h, all of them accumulated cadrnium(14ppm~57ppm) In cell. In cadinium-resistant bacteria, CM1, CM2, and CM4 were spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$, CM4 were also spared from the Inhibitory effect of $Cd^{2+}$ by the addition of $Mn^{2+}$ as well as $Zn^{2+}$.

• 한국추진공학회지
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• 제21권6호
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• pp.32-38
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• 2017

가소제는 추진제 혼화 시 흐름성과 공정성을 향상시키는 역할을 한다. 대표적인 가소제로서 DOS, DOA, IDP, BTTN 등이 있다. 특히 BTTN은 에너지 가소제로서 추진제 성능에 도움을 주는 물질이며, 다양하게 사용되고 있다. 그러나 이 물질들은 충격감도가 비교적 민감하다는 단점이 있다. 본 연구에서는 둔감한 에너지 가소제를 개발하기 위해 트리아졸 계열의 4,5-bis (azidomethyl)-(1-butyl)-1,2,3-triazole (1-DABTR)을 합성하고 이화학적 특성 분석을 하였다. 또한, 분광분석(NMR, IR)을 통해 1-DABTR의 구조를 분석하였고, 유리전이온도, 녹는점, 분해온도, 밀도, 점도, 충격감도 등의 물리적 특성을 측정하였다. 그리고 Gaussian 09를 이용하여 생성열을 계산하였다.

• 폴리머
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• 제36권2호
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• pp.163-168
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• 2012

최근에 내시경 관련기술의 진보에 따라서 시술 편리성, 회복시간 단축, 환자 고통 경감 등의 장점으로 인해 스텐트 삽입술이 빠르게 진보하였다. 본 연구에서 양성담관 협착 치료를 목적으로 파클리탁셀을 이용한 약물방출 스텐트를 전기분사 방법에 의해 제조하였으며, 이 때 사용된 고분자는 polyether-based polyurethane(상표명 : PELLETHANE 2363-80AE$^{(R)}$)과 첨가제로서 Pluronic F127, 약물로서 파클리탁셀을 사용하여 금속스텐트 표면에 코팅하였다. 그 결과로서, 약물이 코팅된 고분자 필름의 물리적 특성은 SEM, FTIR, 접촉각 측정기, XRD에 의해 확인하였으며, 약물방출속도는 약물함량이 높을수록 감소하였음을 알 수 있었다.

• 생명과학회지
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• 제16권1호
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• pp.148-155
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• 2006

창원시 주요하천의 미생물군집의 다양성을 quinone profile 방법을 이용하여 분석하였다. 그리고 온도, pH, 용존산소(DO), 용존탄소(DOC)와 화학적 산소 요구량(BOD)등 물리화학적 성상도 조사하였다. Ubiquinone UQ-8, UQ-9, UQ-10은 모든 조사 하천에서 관찰되었다. UQ-8은 가을의 남천하류, 토월천, 가음정천을 제외한 모든 하천에서 주요 퀴논 분자종이었으며, 겨울철에는 하남천, 토월천, 가음정천과 남산천을 제외한 하천에서 역시 주요 퀴논 분자종임이 확인되었다. DOC가 높을수록 가을철에는 plastoquinone(PQ-9)의 농도가 높았으며, 겨울에는 total quinone의 농도가 높았다. 상관분석 결과 BOD도 하천의 PQ농도를 좌우하는 주요 요인으로 확인되었다.

• Journal of Pharmaceutical Investigation
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• 제34권6호
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• pp.443-452
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• 2004

Habit is the description of the outer appearance of a crystal. If the environment of a growing crystal affects its external shape without changing its internal structure, a different habit results. Crystal habit and the internal structure of a drug can affect bulk and physicochemical properties, which range from flowability to chemical stability. A polymorph is a solid crystalline phase of a given compound resulting from the possibility of at least two different arrangements of the molecules of that compound in the solid state. Chemical stability and solubility changes due to polymorphism can have an impact on a drug's bioavailability and its development program. During crystallization from a solution, crystals separating may consist of a pure component or be a molecular compound. Solvates are molecular complexes that have incorporated the crystallizing solvent molecule in their lattice. When the solvent incorporated in the solvate is water, it is called a hydrate. To distinguish solvates from polymorphs, which are not molecular compounds, the term pseudopolymorph is used. Identification of possible hydrate compounds is important since their aqueous solubilities can be significantly less than their anhydrous forms. Conversion of an anhydrous compound to a hydrate within the dosage form may reduce the dissolution rate and extent of drug absorption. An amorphous solid may be treated as a supercooled liquid in which the arrangement of molecules is random. Amorphous solids lack the three-dimensional long-range order found in crystalline solids. Since amorphous forms are usually of higher thermodynamic energy than corresponding crystalline forms, solubilities as well as dissolution rates are generally greater. A study on crystal form includes characterization of (l)crystal habit, (2)polymorphism, (3)pseudopolymorphism, (4)amorphous solid.

• Journal of Pharmaceutical Investigation
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• 제38권2호
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• pp.119-126
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• 2008

Solid dispersions of poorly water-soluble drug, sibutramine, were prepared with hydrophilic polymer, poly-N-vinylpyrrolidone (PVP), hydroxypropylmethylcellulose (HPMC) and organic acid, citric acid, to improve the solubility of drug. Physicochemical variation and shape of microsphere were characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and Fourier-transform infrared spectroscopy (FT-IR). Microspheres containing additives showed more spherical shape than non additive microspheres. In vitro release behavior of microspheres presented at simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8). The solid dispersion form transformed the drug into an amorphous state and dramatically improved its dissolution rate. These data suggest that the solid dispersion technique is an effective approach for developing the appetite depressant drug products and various pharmaceutical excipients are able to control the release behaviors.

• 한국표면공학회지
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• 제50권5호
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• pp.322-331
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• 2017

Hydrogen evolution reaction(HER) was studied over $Ni_4Cr$ nanofibers(NFs) prepared by electrospinning method and oxidation/reduction heat treatment for alkaline water electrolysis. The physicochemical and electrochemical properties such as average diameter, lattice parameter, HER activity of synthesized $Ni_4Cr$ NFs could be modified by proper electrospinning process condition and reduction temperature. It was shown that $Ni_4Cr$ NFs had average diameter from 151 to 273 nm. Also, it exhibited the overpotential between 0.419 V and 0.526 V at $1mA/cm^2$ and Tafel slope of -334.75 mV to -444.55 mV per decade in 1 M KOH solution. These results indicate that $Ni_4Cr$ NFs with reduction heat treatment at $600^{\circ}C$ show thinnest diameter and highest HER activity among the other catalysts.