• 상하수도학회지
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• 제27권4호
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• pp.457-468
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• 2013

Based on the activated sludge model(ASM), a mathematical model which represents the aerobic sludge digestion by sequencing batch reactor(SBR) combined with ultrasonic treatment was composed and performed in this study. Aerobic digestion using sequencing batch reactor(SBR) equipped with ultrasound treatment was also experimented for the purpose of parameter calibration. Most of the presented kinetic parameters in ASM or ASM2 could be used for the aerobic digestion of sludge but the parameters related in hydrolysis and decay rate needed modification. Hydrolysis rate constant of organic matter in aerobic condition was estimated at $0.3day^{-1}$ and the maximum growth rate for autotrophs in aerobic condition was $0.618day^{-1}$. Solubilization reactions of particulate organics and nitrogen by ultrasonication was added in this kinetic model. The solubilization rate is considered to be proportional to the specific energy which is defined by specific ultrasound power and sonication time. The solubilization rate constant by ultrasonication was estimated at $0.202(W/L)^{-1}day^{-1}$ in this study. Autotrophs as well as heterotrophs also decomposed by ultrasonic treatment and the nitrification reaction was limited by the lack of autotrophs accumulation in the digester.

• 한국환경과학회지
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• 제25권6호
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• pp.817-827
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• 2016

The resistance in series model has been frequently used for determination of various filtration resistance to correctly understand the membrane fouling behaviour in MBR (membrane bio-reactor) for wastewater treatment. The cake layer resistance ($R_c$) which is commonly determined by calculation of flux dataset that are obtained empirically before and after removing the cake layer on membrane surface. However, the calculated Rc values are very dependent on the cleaning methods adapted for removal of cake layer. This study investigated how the various cleaning options affect $R_c$. Seven different cleaning methods were employed: i) ultrasonication (100 W, 10 min), ii) ultrasonication (200 W, 60 min), iii) ultrasonication (400 W, 120 min), iv) water rinsing in a shaker (100 rpm, 10 min), v) water rinsing in a shaker (300 rpm, 60 min), vi) water rinsing, vii) sponge scrubbing. For the hydrophilic PES membrane, the cake layer removal efficiencies ranged from 64% to 10%, indicating that the removal of cake layer was highly dependent on the cleaning options. For the hydrophobic PVDF membrane, the cake layer removal efficiencies ranged from 79% to 97%. Consequently, a standardized method for cake layer removal to determine cake resistance ($R_c$) is needed for correct interpretation of the fouling phenomena.

• 한국진공학회지
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• 제17권2호
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• pp.170-174
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• 2008

고립된 탄소나노튜브를 얻기 위해 계면활성제 Sodium Dodecyl Sulfate(SDS) 수용액에 단층 탄소나노튜브 분말을 넣어 초음파 처리를 하는 과정 중에 발생하는 물성 변화를 라만과 Photoluminescence를 통하여 연구하였다. 단층 탄소나노튜브(SWCNT) radial breathing mode(RBM)의 라만신호 세기의 변화는 SWCNT의 chirality에 따라 서로 다른 경향성을 보이고 초음파 처리 시간에 영향을 받음을 확인하였다. 또한 동일한 농도의 계면활성제에 담긴 SWCNT의 농도가 커지면 G-band 라만 진동수가 작아지면서 Photoluminescence 세기가 증가하는 현상을 관측하였다.

• Journal of Ginseng Research
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• 제43권4호
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• pp.606-617
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• 2019

Background: The Panax ginseng berry extract (GBE) is well known to have an antidiabetic effect. The aim of this study is to evaluate and investigate the protective effect of ultrasonication-processed P. ginseng berry extract (UGBE) compared with GBE on liver fibrosis induced by mild bile duct ligation (MBDL) model in rats. After ultrasonication process, the composition ratio of ginsenoside in GBE was changed. The component ratio of ginsenosides Rh1, Rh4, Rg2, Rg3, Rk1, Rk3, and F4 in the extract was elevated. Methods: In this study, the protective effect of the newly developed UGBE was evaluated on hepatotoxicity and neuronal damage in MBDL model. Silymarin (150 mg/kg) was used for positive control. UGBE (100 mg/kg, 250 mg/kg, 500 mg/kg), GBE (250 mg/kg), and silymarin (150 mg/kg) were orally administered for 6 weeks after MBDL surgery. Results: The MBDL surgery induced severe hepatotoxicity that leads to liver inflammation in rats. Also, the serum ammonia level was increased by MBDL surgery. However, the liver dysfunction of MBDL surgery-operated rats was attenuated by UGBE treatment via myeloid differentiation factor 88-dependent Toll-like receptor 4 signaling pathways. Conclusion: UGBE has a protective effect on liver fibrosis induced by MBDL in rats through inhibition of the TLR4 signaling pathway in liver.

• 한국식품과학회지
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• 제54권1호
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• pp.80-87
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• 2022

본 연구에서는 초음파 및 유기산 처리에 따른 재배유형별 마늘의 저장 중 품질 특성 조사를 위해 초음파(60℃, 5 min)와 유기산(citric acid 1.0%, fumaric acid 0.5%, 각각 5 min) 처리 후 냉장(4℃) 온도에서 28일간 저장하면서 품질 특성을 조사하였다. 총균수는 한지형과 난지형 모두 대조구와 citric acid 처리 시 저장 기간이 증가할수록 총균수도 증가하였다. 대장균은 한지형과 난지형 모두 대조구에서 저장 7일부터 검출되기 시작하였으며, 그 수준은 식품공전의 신선 편의 식품 법적인 기준 2.0 log CFU/g을 초과하였다. 곰팡이도 대장균과 마찬가지로 저장 7일부터 검출되기 시작하였으나 초음파 처리 시에는 저장 기간 중 모든 재배유형별 마늘에서 검출되지 않았다. Fumaric acid 0.5%를 고려했을 때 총균수는 0.06±0.13으로 한지형과 난지형이 동일하였고, 곰팡이는 한지형 0.68±0.25와 난지형은 증식하지 않는 등 낮은 수준을 유지하고 있었으며, 대장균은 검출되지 않아 미생물 억제에 효과적이었다. 무기질 변화 분석 결과 모든 재배유형별 마늘에서 Fe와 Zn은 검출되지 않았으며 성분이 많은 함유량은 K, P, Mg, Ca, Na 순으로 이었다. 경도는 전반적으로 저장 기간이 증가할수록 감소하는 경향을 보였는데, fumaric acid 처리구에서는 모든 재배유형에서 경도에 유의적인 차이가 없어 조직변화 측면에서 fumaric acid 0.5%, 5분 처리가 가장 효과적인 것으로 나타났다. 색도는 L값은 감소, a값과 b값은 증가하여 육안으로 보았을 때 녹변현상과 일치하였다. 따라서 본 연구에서 활용한 전처리 조건에서는 일부 기간 미생물 감소, 무기질 및 경도, 색 변화와 같은 품질을 유지하는 방안으로 fumaric acid 0.5%, 5분 처리가 마늘의 미생물 저감과 품질 유지에 효과적인 것으로 나타났다. 그러나 채소류의 미생물, 색, 경도 등 품질을 향상하고 유지할 수 있는 다양한 물리적, 화학적인 방법들이 추가로 연구되어야 할 것으로 사료된다.

• 통합자연과학논문집
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• 제8권3호
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• pp.147-152
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• 2015

Photoluminescent porous silicon (PSi) were prepared by an electrochemical etch of n-type silicon under the illumination with a 300 W tungsten filament bulb for the duration of etch. The red photoluminescence emitting at 620 nm with an excitation wavelength of 450 nm is due to the quantum confinement of silicon nanocrystal in porous silicon. As-prepared PSi was sonicated, fractured, and centrifuged in toluene to obtain photoluminescence silicon quantum dots. BET and BHJ methods were employed to study the specific surface area of as-prepared PSi. Optical characterization of red photoluminescent silicon nanocrystal was investigated by UV-vis and fluorescence spectrometer. Also SEM and TEM images of porous silicon and nanoparticles were investigated.

• KSBB Journal
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• 제7권3호
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• pp.166-171
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• 1992

생물응집체 개발을 목적으로 Zoogloea ramigera115를 이용하여 균주배양 및 생물고분다 생성실험을 시시하였다. 다당류 최고 생성률을 얻을 수 있는 최적기질로 탄소원으로는 glucose, 질소원으로는 $NaNO_3$ 유기영양원으로는 yeast extract가 선택되었다. 초기 pH가 6일 때 가장 높은 세포성장과 점성을 나타내었다. 생성돈 생물고분자는 ultrasonication과 고속 원심분리를 거친 후 propanol 첨가에 의해 효율적으로 추출되었다. 생물고분자는 jae test에 의한 응집실험에서 높은 침강성을 보여 응집제 사용가능성을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1633-1634
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• 2004

• Bulletin of the Korean Chemical Society
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• 제10권6호
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• pp.595-599
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• 1989

The effects of phosphatidic acid(PA) on the activity of phospholipase D were examined in detail. The enzyme activity was examined in the liposome system containing phosphatidylcholine and PA, which was suspended in a desired buffer solution by ultrasonication. The substrate of large unilamella vesicle (LUV) state by ultrasonication was more effective on the enzyme activity than that of multilamella vesicle(MLV) by water-bath type sonication. The most effective molar ratio of PC-PA liposome for enzyme activity was found to be 1:0.7. The other optimum conditions were found 5 mM $Ca^{2+}$ ion, pH 6.6, and incubation temperature of $27^{\circ}C. K_m \;and \;V_{max}$ values were estimated to be 1.43 mM and 0.8 $nmole/min/{\mu}g$ protein respectively. These properties in a PC-PA liposome system were compared with those in a PC-SDS mixed micelle system. The effects of other phospholipids and organic phosphates on the enzyme activity were also examined.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.174-175
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• 2021

Currently, the construction structures become larger and more high-performance in modern society, demands for ultra-high strength and light weight construction materials are increasing rapidly. Therefore, this study aims to confirm the applicability of nanomixed cement supplemented with physical and mechanical properties using nanomaterials.Changes in compressive strength and properties were analyzed according to the ratio of cement paste and dispersant (PCE) made by ultrasonication of carbon nanotubes (CNT)