• 한국수산과학회지
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• 제56권1호
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• pp.21-27
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• 2023

Lotus Nelumbo nucifera seed protein (LSP) was isolated by alkaline solubilization after removing fat and phenolics by hexane and ethanol treatment. Antioxidant peptides from LSP were produced with Alcalase^® and pepsin and hydroxyl radical scavenging activities were determined. LSP-Alcalase^® hydrolysates showed higher hydroxyl radical scavenging activity than LSP-pepsin hydrolysates. To purify antioxidant peptides, LSP-Alcalase^® hydrolysates were subjected to high performance liquid chromatography (HPLC) separation on the C18 column and the active fraction was further purified using a Superdex^TM peptide 10/300 GL column. Finally, the active fraction (F8-2) was evaluated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging, and oxygen radical absorbance capacity (ORAC) assays. The EC₅₀ values of the F8-2 were 105.81±0.02 ㎍/mL for DPPH and 32.26±0.02 ㎍/mL for hydroxyl radical and the F8-2 exhibited 7.22 μM trolox equivalent (TE)/100 ㎍ F8-2. Glutathione (GSH), which is a positive control, showed EC₅₀ values of 19.87±0.01 ㎍/mL for DPPH and 15.95±0.03 ㎍/mL for hydroxyl radical and an ORAC value of 14.17±0.03 μM TE/100 ㎍ GSH. Finally, sixteen peptides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among them, Ile-Tyr and Leu-Tyr showed higher antioxidant scores.

• 한국전기전자재료학회논문지
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• 제24권12호
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• pp.939-943
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• 2011

In this paper, reliability of the two sandwiched MIM capacitors of $Al_2O_3-HfO_2-Al_2O_3$ (AHA) and $SiO_2-HfO_2-SiO_2$ (SHS) with hafnium-based dielectrics was analyzed using two kinds of voltage stress; DC and AC voltage stresses. Two MIM capacitors have high capacitance density (8.1 fF/${\mu}m^2$ and 5.2 fF/${\mu}m^2$) over the entire frequency range and low leakage current density of ~1 nA/$cm^2$ at room temperature and 1 V. The charge trapping in the dielectric shows that the relative variation of capacitance (${\Delta}C/C_0$) increases and the variation of voltage linearity (${\alpha}$/${\alpha}_0$) gradually decreases with stress-time under two types of voltage stress. It is also shown that DC voltage stress induced greater variation of capacitance density and voltage linearity than AC voltage stress.

• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.93-97
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• 2009

The nanoporous $F:SnO_2$ materials have been prepared through the controlled hydrolysis of fluoro(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin followed by thermal treatment at $400-550^{\circ}C$. The main IR features include resonances at 660, 620 and 540 cm-1. From the TG-DTG result, three main mass losses of 6.5, 13.3 and 3.8 at 81, 289 and $490^{\circ}C$ are observed between 50 and $650^{\circ}C$ yielding a final residue of 76.0%. The size of Sn $O_2$ nanoparticles rose from 5 nm to 10-12 nm as the temperature of thermal treatment is increased from 400 to $550^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제18권5호
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• pp.389-395
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• 2005

The etching technology of the high aspect ratio contact(HARC) is necessary at the critical contact processes of semiconductor devices. Etching the $SiO_{2}$ contact hole with the sub-micron design rule in manufacturing VLSI devices, the unexpected phenomenon of 'profile tilting' or 'bottom distortion' is often observed. This makes a short circuit between neighboring contact holes, which causes to drop seriously the device yield. As the aspect ratio of contact holes increases, the high C/F ratio gases, $C_{4}F_{6}$, $C_{4}F_{8}$ and $C_{5}F_{8}$, become widely used in order to minimize the mask layer loss during the etching process. These gases provide abundant fluorocarbon polymer as well as high selectivity to the mask layer, and the polymer with high sticking yield accumulates at the top-wall of the contact hole. During the etch process, many electrons are accumulated around the asymmetric hole mouth to distort the electric field, and this distorts the ion trajectory arriving at the hole bottom. These ions with the distorted trajectory induce the deformation of the hole bottom, which is called 'profile tilting' or 'bottom distortion'. To prevent this phenomenon, three methods are suggested here. 1) Using lower C/F ratio gases, $CF_{4}$ or $C_{3}F_{8}$, the amount of the Polymer at the hole mouth is reduced to minimize the asymmetry of the hole top. 2) The number of the neighboring holes with equal distance is maximized to get the more symmetry of the oxygen distribution around the hole. 3) The dual frequency plasma source is used to release the excessive charge build-up at the hole mouth. From the suggested methods, we have obtained the nearly circular hole bottom, which Implies that the ion trajectory Incident on the hole bottom is symmetry.

• 한국결정성장학회지
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• 제25권3호
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• pp.116-120
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• 2015

혼합이온 전도체인 $K_2NiF_4$-type 산화물인 $La(Ca)_2Ni(Cu)O_{4+{\delta}}$ 분말을 합성하여 결정구조 분석과 분말의 나노구조화에 따른 고체산화물 연료전지의 양극 성능을 비교 평가하였다. 이온 반경이 큰 Cu가 Ni 자리에 치환되어 Ni-O 팔면체 구조에서 c 축 방향으로 결정구조가 팽창하였으며, Ni-Cu의 Jahn-Teller 뒤틀림으로 산소이온 산화 환원 반응과 이온 전도도 특성에 영향을 주었다. 특히 나노구조의 $La(Ca)_2Ni(Cu)O_{4+{\delta}}$ 분말의 경우 표면 촉매성능이 향상되어 단위 전지 성능 향상 결과를 얻을 수 있었다. Ni-YSZ 음극 지지체에 8YSZ 전해질을 dip-coating한 후 $La(Ca)_2Ni(Cu)O_{4+{\delta}}$ 분말을 양극으로 도포하여 얻은 SOFC 단위성능 측정 결과 $800^{\circ}C$에서 $1w/cm^2$의 최대 출력 값을 얻을 수 있었다.

• 한국식품영양과학회지
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• 제22권2호
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• pp.202-207
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• 1993

렌넷유청, 인삼, 감미료, 꿀, 매실 등에 종류가 다른 유산균주들을 접종하여 인삼 유청음료를 제조한 후, 일부는 발효시키고 일부는 비발효 상태로 4$^{\circ}C$ 및 30$\pm$1$^{\circ}C$에 저장하여 1, 3, 5주에 관능검사를 실시하였다. 관능검사 결과, 감미료와 꿀을 첨가하여 냉장보관 한 유산균 비발효 인삼 유청음료(A)는 단맛이 강하고 신맛, 쓴맛, 떫은맛, 뒷맛이 적어서 전체적인 평가에서 8.64~8.85으로 가장 높은평가를 받았고 Lac. caseisub-sp. casei와 Str. salivarius sbu-sp. thermophilus를 접종하여 냉장보관한 인삼 유청음료 (C)와 감미료, 꿀 및 매실을 첨가하여 실온보관한 인삼 유청음료(D)가 대체로 좋은 평가를 받았으나 실온보관한 유산균 발효 음료(E, F)는 2.92~3.58로 가장 낮은 평가를 받았으므로 이의 개선이 요구된다.

• 한국자원식물학회지
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• 제34권5호
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• pp.433-442
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• 2021

본 연구에서는 발효홍삼과 발효하지 않은 홍삼을 BALB/c mouse에 경구투여한 후 혈청을 채취하여 주요 진세노사이드 생체이용율을 LC-MS/MS이용하여 분석하였다. 또한 이들의 항염효과를 IL-1𝛽, TNF 정량분석을 통해 비교하였다. 홍삼을 발효하였을 때, Rd를 포함한 전체적인 총 진세노사이드 함량이 증가하는 것을 확인하였으며, 마우스에게 투여하였을 총 진세노사이드 TG 의 혈액 검출량 AUC 또한 발효홍삼을 섭취하였을 때 높은 것을 확인하였다. C_max값 또한 동일하게 발효홍삼을 섭취하였을 때 증가하는 것을 확인하였다. 염증지표를 확인 하였을때 유도군과 비교하여 IL-1𝛽, TNF의 감소효과는 확인하였으나 그룹간의 유의적 차이는 발생하지 않았다. 이상의 연구결과로 probiotics가 발효홍삼의 ginsenoside 생체이용율을 향상시키는 중요한 요인임을 확인하였고, 이는 probiotics를 이용한 천연물 발효제제의 적용 확장과 그 산업적 활용성 증대에 기여할 수 있을 것으로 사료된다.

• Membrane and Water Treatment
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• 제2권3호
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• pp.187-205
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• 2011

The electric transport of the mixture of hydrochloric and phosphoric acids through strong base (Neosepta ACM) and weak base (Selemion AAV) anion-exchange membranes was investigated. The instantaneous efficiency of HCl removal from the cathode solution, $CE_{Cl}$, with and without $H_3PO_4$ was determined. It was found that $CE_{Cl}$ was 0.8-0.9 if the number of moles of elementary charge passed through the system, $n_F$, did not exceed ca. 80% of the initial number of HCl moles in the cathode solution, $n_{Cl,ca,0}$. The retention efficiency of $H_3PO_4$ in that range was close to one. The transport of acid mixtures was satisfactorily described by a model based on the extended Nernst-Planck and Donnan equations for $n_F$ not exceeding $n_{Cl,ca,0}$. Among the tested model parameters, most important were: concentration of fixed charges, the porosity-tortuosity coefficient, and the partition coefficient of an undissociated form of $H_3PO_4$. For the both membranes, the obtained optimal values of fixed charge concentration, $\bar{c}_m$, were up to 40% lower than the literature values of $\bar{c}_m$ obtained from the equilibrium measurements. Regarding the $H_3PO_4$ equilibria, it was sufficient to consider $H_3PO_4$ as a monoprotic acid.

• 한국세라믹학회지
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• 제53권4호
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• pp.456-462
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• 2016

$NaCaGd(MoO_4)_3:Ho^{3+}/Yb^{3+}$ ternary molybdates were successfully synthesized by microwave sol-gel method for the first time. Well-crystallized particles formed after heat-treatment at $900^{\circ}C$ for 16 h showed a fine and homogeneous morphology with particle sizes of $3-5{\mu}m$. Under excitation at 980 nm, the UC intensities of the doped samples exhibited strong yellow emissions based on the combination of strong emission bands at the 520-nm and 630-nm emission bands in the green and red spectral regions, respectively. The strong 520-nm emission band in the green region corresponds to the $^5S_2/^5F_4{\rightarrow}^5I_8$ transition of $Ho^{3+}$ ions, while the strong 630-nm emission band in the red region appears to be due to the $^5F_5{\rightarrow}^5I_8$ transition of the $Ho^{3+}$ ions. The optimal $Yb^{3+}:Ho^{3+}$ ratio was found at 9:1, as indicated by the composition-dependent quenching effect of $Ho^{3+}$ ions. The pump power dependence of the upconversion emission intensity and the Commission Internationale de L'Eclairage chromaticity coordinates of the phosphors were evaluated in detail.

• Transactions on Electrical and Electronic Materials
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• 제18권6호
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• pp.364-369
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• 2017

Double molybdate $NaGd_{1-x}(MoO_4)_2:Ho^{3+}/Yb^{3+}$ phosphors with proper doping concentrations of $Ho^{3+}$ and $Yb^{3+}$ ($x=Ho^{3+}+Yb^{3+}$, $Ho^{3+}=0$ and 0.05, and $Yb^{3+}=0$, 0.35, 0.40, 0.45, and 0.50) were successfully synthesized using the microwave sol-gel method. Well-crystallized particles formed after heat-treatment at $800^{\circ}C$ for 16 h showed fine and homogeneous morphologies with particle sizes of $1{\sim}3{\mu}m$. The spectroscopic properties were examined using photoluminescence emission and Raman spectroscopy. Under excitation at 980 nm, the upconversion doped samples exhibited strong yellow emissions, from the combination of strong emission bands at 545 nm and 655 nm in the green and red spectral regions, respectively. The strong 545 nm emission band in the green region corresponded to the $^5S_2/^5F_4{\rightarrow}^5I_8$ transition in the $Ho^{3+}$ ions, while the strong 655 nm band in the red region appeared because of the $^5F_5{\rightarrow}^5I_8$ transition in the $Ho^{3+}$ ions. The pump power dependence and the Commission Internationale de L'Eclairage chromaticity of the upconversion emission intensity were evaluated in detail.