• 청정기술
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• 제16권2호
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• pp.140-144
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• 2010

리튬이온전지의 음극활물질로서 titania-silica 혼합물을 얻기 위해 TiCl4와 TEOS를 전구체로 사용하여 졸-겔법을 이용해 합성하였다. 졸-겔법을 이용하여 혼합물을 합성할 경우에 균일한 분포를 갖는 화합물을 제조할 수 있다. 마이크로파를 이용하여 혼합물을 열처리하여 새로운 물성을 갖는 화합물의 제조를 시도하였다. 합성한 화합물의 물성을 측정하기 위하여 화합물의 조성, 열처리 온도 및 마이크로파 처리등을 실험변수로 사용하였다. 특성 분석방법으로는 합성물질의 구조적 특성과 입자의 표면분석을 하기 위해 XRD(X-ray diffraction)와 SEM (scanning electron microscopy)과 전지 충 방전기를 사용하여 충 방전에 따르는 전지의 용량변화를 관찰하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.275-281
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• 2003

$Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$ and $Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$:$Co^{2+}$ single crystals were grown by CTR method. The grown single crystals have defect chalcopyrite structure with lattice constant a=5.5966$\AA$, c=10.8042$\AA$ for the pure, a=5.6543$\AA$, c=10.8205$\AA$ for the Co-doped single crystal, respectively. The optical energy band gap was given as indirect band gap. The optical energy band gap was decreased according to add of Co-impurity Temperature dependence of optical energy band gap was fitted well to the Varshni equation. From this relation, we can deduced the entropy, enthalpy and heat capacity. Also, we can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_{d}$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• 한국수소및신에너지학회논문집
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• 제8권4호
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• pp.173-180
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• 1997

The Mechanically Alloyed $Ti_{0.7}Mg_{0.3}Ni$ was investigated as a function of milling time by X-ray diffraction, SEM(scanning electron microscope), EDS(energy dispersive spectrometer), P-C-Isotherm curves. After 10hrs milling, mixed $Ti_{0.7}Mg_{0.3}Ni$ powders were changed to amorphous phase. And amorphous $Ti_{0.7}Mg_{0.3}Ni$ alloys became TiNi phase crystalline after heat treatment at 873K in a vacuum for 1 hour. The hydrogen absorption capacity of the annealed $Ti_{0.7}Mg_{0.3}Ni$ alloy increased as a function of mechanical alloying time.

• Transactions on Electrical and Electronic Materials
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• 제13권3호
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• pp.121-124
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• 2012

Olivine type $LiFePO_4$ cathode material was synthesized by solid-state reaction method including one-step heat treatment. To improve the electrochemical characteristics, graphite nanofiber (GNF) was added into $LiFePO_4$ cathode material. The structure and morphological performance of $LiFePO_4$ were investigated by X-ray diffraction (XRD); and a field emission-scanning electron microscope (FE-SEM). The synthesized $LiFePO_4$ has an olivine structure with no impurity, and the average particle size of $LiFePO_4$ is about 200~300 nm. With graphite nanofiber added, the discharge capacity increased from 113.43 mAh/g to 155.63 mAh/g at a current density of 0.1 $mA/cm^2$. The resistance was also significantly decreased by the added graphite nanofiber.

• BMB Reports
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• 제45권8호
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• pp.476-481
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• 2012

Flavodoxin (Fld) has been demonstrated to bind to ferredoxin-NADP$^+$ reductase A (FprA) in Pseudomonas putida. Two residues ($Phe^{256}$, $Lys^{259}$) of FprA are likely to be important for interacting with Fld based on homology modeling. Site-directed mutagenesis and pH-dependent enzyme kinetics were performed to further examine the role of these residues. The catalytic efficiencies of FprA-$Ala^{259}$ and FprA-$Asp^{259}$ proteins were two-fold lower than those of the wild-type FprA. Homology modeling also strongly suggested that these two residues are important for electron transfer. Thermodynamic properties such as entropy, enthalpy, and heat capacity changes of FprA-$Ala^{259}$ and FprA-$Asp^{259}$ were examined by isothermal titration calorimetry. We demonstrated, for the first time, that $Phe^{256}$ and $Lys^{259}$ are critical residues for the interaction between FprA and Fld. Van der Waals interactions and hydrogen bonding were also more important than ionic interactions for forming the FprA-Fld complex.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.88-93
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• 2002

$Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$ and $Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}:Co^{2+}$ + single crystals were grown by CTR method. The grown single crystals have defect chalcopyrite structure with lattice constant a= 5.5966A. c= 10.8042${{\AA}}$ for the pure. a= 5.6543${{\AA}}$. c= 10.8205${{\AA}}$ for the Co-doped single crystal. respectively. The optical energy band gap was given as indirect band gap. The optical energy band gap was decreased according to add of Co-impurity. Temperature dependence of optical energy band gap was fitted well to the Varshni equation. From this relation. we can deduced the entropy. enthalpy and heat capacity. Also. we can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• Journal of Electrochemical Science and Technology
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• 제4권3호
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• pp.113-118
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• 2013

Fluorophosphate, $Na_2MnPO_4F$ as new cathode material was synthesized by carbothermal treatment method. Prepared $Na_2MnPO_4F$ has particle size under 100 nm and residual carbon exists in surface of $Na_2MnPO_4F$. Additional carbon coating was performed in order to increase the electrochemical properties. Even capacity and overpotential were improved by carbon coating using mechanical ball milling, the reduced crystallinity limited the drastic improvement of the electrochemical properties. To solve this problem, re-heat treatment was involved to recover crystallinity and then notable improvement of electrochemical properties was obtained. Specific amount of $Li^+$ that participates in electrochemical $Li^+$ insertion / extraction reaction, was x = 1 in $Li_xNa_{2-x}MnPO_4F$ within the voltage range of 2.0 to 4.8 V. The doubled capacity by 2 electron reaction can be obtained when NMPF is charged to higher voltage over 4.8 V.

• 한국식품과학회지
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• 제24권5호
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• pp.463-469
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• 1992

열공정이 생선단백질의 조직 형성에 미치는 영향을 단백질 sol의 열안정성과 가열시의 rigidity 형성 및 최종 겔의 구조적인 측면으로 살펴보았다. 가열하는 동안에 나타나는 변성 피크는 소금첨가에 따라서, 가열속도에 따라서 또한 낮은 온도에서의 전처리에 따라 변성온도가 사라지거나 낮은 쪽으로 이동하였고 단백질의 열용량도 줄어들고 불안정한 상태로 변하였다. $4^{\circ}C$에서의 전처리는 가열시 조직의 굳기형성에 지속적인 상승효과를 가져왔고 많은 탄성력의 증가를 가져왔으나, $40^{\circ}C$에서의 전처리는 일시적으로 조직강도의 증가만 가져왔다. 그러나 낮은 온도($4^{\circ}C$ 나 $40^{\circ}C$)에서의 전처리 후 생성되는 겔 내부조직은 큰 집성물이 보이는 구조적 유사성을 보였으며, SH기를 변형시킨 겔의 구조도 조직의 강도변화를 나타내는 특징을 나타내었다.

• 대한화학회지
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• 제61권6호
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• pp.339-345
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• 2017

자동차 폐타이어 분말(WTP)을 질소분위기 하에서 2시간 동안 $400^{\circ}C$의 온도에서 열처리하여 탄소질 흡착제(CA-WTP)로 만들고, 이들에 대한 열 중량 분석, 에너지 변환 X-선 분석, 주사전자 현미경, 비표면적 측정, 적외선 분광기들을 통해 특성을 파악한 후, 수중의 Cd의 제거를 위한 흡착제로서 시험하였다. 열처리한 CA-WTP는 WTP보다도 매우 높은 비표면적과 총 세공부피 그리고 Cd에 대해 높은 흡착효율을 나타내었다. 흡착의 평형 데이터는 Freundlich와 Langmuir 흡착 등온선 모델을 이용하여 평가하였고, 위 두 흡착 등온선 모두 0.95보다 큰 상관계수($R^2$) 값을 나타내었다. 연구의 결과는 열처리 한 폐타이어 분말(CA-WTP)이 수중으로부터 Cd을 흡착하는데 효율적인 흡착제로 사용될 수 있다는 것을 보였다.

• 동아시아식생활학회지
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• 제26권6호
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• pp.498-506
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• 2016

A croquette added with heat-treated kimchi at 20% showing higher sensory preferences was analyzed for its physicochemical properties and antioxidant activity using a croquette without kimchi as a control. Compared with the control, kimchi-added croquette had 3.3-fold higher organic acids content (p<0.001), resulting in a significant reduction of pH (p<0.001) and higher metal chelating activity (p<0.001). Upon addition of kimchi, total reducing capacity increased from 109.4 to $139.4{\mu}g/g$ gallic acid equivalents (p<0.01), and DPPH radical scavenging activity also increased 2-fold, which corresponded to 54% of the electron-donating ability of 0.35 mM gallic acid. In addition, contents of free amino acids and ${\gamma}-aminobutyric$ acid (GABA) appreciably increased by 1.6-fold (p<0.01) and 10-fold (p<0.001), respectively. This could be attributed to the ingredients of kimchi and/or enzymatic transformation of precursors by microorganisms during kimchi fermentation. Kimchi-added croquette was determined to be a good source of dietary fiber relative to its calorie content. Texture profile analysis showed no significant differences in hardness, springiness, cohesiveness, gumminess, and chewiness between the two croquettes with or without kimchi. Taken together, this study shows that utilization of heat-treated kimchi as a filling for croquette could be a good strategy to improve both the nutritional quality and antioxidant activity of croquette.