• Natural Product Sciences
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• 제14권2호
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• pp.113-117
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• 2008

Saururus chinensis is a commonly used folk herb for the treatment of edema and liver diseases in Korea. To study the biological activity of Saururus chinensis in bone metabolism, we evaluated the effect of its extracts on osteoclast differentiation in vitro using primary mouse bone marrow-derived macrophages. Methanol extract (ME) from dried roots of Saururus chinensis was partitioned into methylene chloride (MF), ethyl acetate (EF), n-butanol (BF) and water fractions (WF). Tartrate-resistance acid phosphatase (TRAP) activity assay and western blot analysis were performed to determine the effect on osteoclast differentiation and mitogen-activated protein (MAP) kinases activation. ME, MF and EF dramatically inhibited receptor activator of ${NF-kB}$ ligand (RANKL)-induced formation of multinucleated osteoclasts and activation of MAP kinases. This study firstly demonstrated that ME, MF and EF of Saururus chinensis have the potential to inhibit the osteoclast differentiation, which results from the inhibition of MAP kinases activations in part.

• Korean Membrane Journal
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• 제7권1호
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• pp.58-66
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• 2005

Nanofiltration (NF) of a dyeing wastewater was carried out using polyamide NF-membranes. Before applying the wastewater to the membrane process, it was pretreated with various chemical coagulants such as alum, ferric chloride and HOC-100A. In order to see the effect of the pretreatment of the wastewater using chemical coagulants on the membrane separation process, the optimum conditions for the coagulation and sedimentation process using the chemical coagulants were sought. By the pretreatment, despite the different coagulants used, the chemical oxygen demand (COD) and UV-absorbance of the wastewater were lowered by more than $70\%$. The pretreated wastewater was then applied to the membrane process. The effect of the coagulants used for the pretreatment on the membrane fouling was studied. From this study, it was found that the HOC-100A was the best out of the coagulants used far the removal of the materials that could cause membrane fouling.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.7-14
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• 2015

In this study, land farming and chemical oxidation of a diesel-contaminated site is compared to evaluate the environmental impact during soil remediation using the Spreadsheet for Environmental Footprint Analysis by U.S. EPA. Each remediation process is divided into four phases, consisting of soil excavation, backfill and transportation (Phase 0), construction of remediation facility (Phase 1), remediation operation (Phase 2), and restoration of site and waste disposal (Phase 3). Environmental footprints, such as material use, energy consumption, air emission, water use and waste generation, are analyzed to find the way to minimize the environmental impact. In material use and waste generation, land farming has more environmental effect than chemical oxidation due to the concrete and backfill material used to construct land farming facility in Phase 1. Also, in energy use, land farming use about six times more energy than chemical oxidation because of cement production and fuel use of heavy machinery, such as backhoe and truck. However, carbon dioxide, commonly considered as important factor of environmental impact due to global warming effect, is emitted more in chemical oxidation because of hydrogen peroxide production. Water use of chemical oxidation is also 2.1 times higher than land farming.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.215-220
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• 2012

ZnO nanoparticles were synthesized through a facile route and were used as ozonation catalysts. With the increase of calcination temperature ($150-300^{\circ}C$), surface hydroxyl groups and catalytic efficiency of asobtained ZnO decreased remarkably, and the ZnO obtained at $150^{\circ}C$ showed the best catalytic activity. Compared with ozonation alone, the degradation efficiency of phenol increased above 50% due to the catalysis of ZnO-150. In the reaction temperatures range from $5^{\circ}C$ to $35^{\circ}C$, ZnO nanocatalyst revealed remarkable catalytic properties, and the catalytic effect of ZnO was better at lower temperature. Through the effect of tertbutanol on degradation of phenol and the catalytic properties of ZnO on degradation of nitrobenzene, it was proposed that the degradation of phenol was ascribed to the direct oxidation by ozone molecules based on solidliquid interface reaction.

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1435-1440
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• 2013

To investigate the influence of the carbon matrix on the electrochemical performance of Si/C composites, four types of Si/C composites were prepared using graphite, petroleum coke, pitch and sucrose as carbon precursors. A ball mill was used to prepare Si/C blends from graphite and petroleum coke, whereas a dispersion technique was used to fabricate Si/C composites where Si was embedded in disordered carbon matrix derived from pitch or sucrose. The Si/pitch-based carbon composite showed superior Si utilization (96% in the first cycle) and excellent cycle retention (70% after 40 cycles), which was attributed to the effective encapsulation of Si and the buffering effect of the surrounding carbon matrix on the silicon particles.

• 폴리머
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• 제31권2호
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• pp.105-110
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• 2007

ABS(acrylonitrile butadiene styrene)수지의 성능저하에 미치는 영향을 알아보기 위해 ABS, 도장, 도료, 사출 등 전 부문에 대한 영향도를 파악함으로써 ABS수지의 성능저하를 최소화하기 위한 최적화 방안을 수립하였다. ABS수지의 성능저하에 영향을 미치는 인자를 실험실 규모에서 검토한 결과 변형에 의한 기계적 요인보다는 사용된 화학물질의 화학적, 물리적 특성에 의한 요인이 지배적인 것으로 나타났다. ABS수지를 이용한 제조 현장에서 여러 인자(ABS수지, 사출, 화학물질, 도장 등)에 대해 검토한 결과 ABS수지 표면에 직접적으로 접촉하는 화학물질인 희석제 (시너)에 의한 영향도가 가장 큼을 확인할 수 있었다. 이번 연구 결과를 통해 수지의 성능저하에 미치는 각 인자별 영향도 수준 평가가 가능하게 되었으며, 이를 토대로 양산 시 나타나는 도장불량 등의 문제해결을 위한 관리 과정의 체계화 및 품질 변동요인의 제거 방안을 구체화할 수 있었다.

• 한국연소학회지
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• 제3권1호
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• pp.11-19
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• 1998

The influence of oxidant addition on soot formation is investigated experimentally with ethylene, propane and mixture fuel co-flow diffusion flames. Oxidant addition into fuel shows the increase of integrated soot volume fractions for ethylene, ethylene/ethane and ethylene/methane mixture flames. However, the increase of integrated soot volume fraction with oxidant addition was not significant for propane and ethylene/propane mixture flames. This discrepancy is explained with $C_2\;and\;C_3$ chemistry at the early stage of soot formation process. The oxidant addition increases the concentration of $C_3H_3$ in the soot formation region, and therefore, enhances soot formation process. A new soot formation rate model that includes both dilution effect and chemical effect of oxygen is suggested to interpret the increase of integrated soot volume fractions with oxidant addition into ethylene. Also, the role of adiabatic flame temperature for the chemical effect of oxygen addition into fuel was reviewed. The influence of oxidant or diluent addition into fuel on soot formation process are the fuel dilution effect, the adiabatic flame temperature altering effect and/or the chemical effect of oxygen. Their relative importance could change with fuel structure and adiabatic flame temperature.

• 공업화학
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• 제21권6호
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• pp.670-675
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• 2010

나노실리카볼 입자를 합성하고 표면에 비닐기를 부여하는 합성 연구를 통해 다양한 크기로 조절이 된 유-무기하이브리드 입자인 비닐-나노실리카볼이 합성되었다. 다양한 크기의 비닐-나노실리카볼 입자를 상업적으로 적용되고 있는 아크릴-멜라민 클리어코트에 후첨시키고 경화시켰을 때, 클리어코트의 광택도 증가 및 유지 특성에 대해 연구하였다. 실리카볼 입자가 250 nm 정도인 경우 Matting effect에 의한 광택도 감소가 관측되었으나 20~30 nm로 작아지면 광택도 유지 효과가 약 7%까지 증가하였다. 나노실리카볼 대신 상업용 친수 실리카 Aerosil 200 (Hydrophilic fumed silica, 평균입도 12 nm, Degussa)을 사용하여 비닐- fumed 실리카 화합물을 합성하여 클리어코트에 적용하면 광택도 유지 효과가 약 2% 정도만 증가하였다.

• 약학회지
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• 제33권3호
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• pp.167-174
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• 1989

KR-1008 and KR-30006 are 1,4-dihydropyridine derivatives, new vasodilatory calcium antagonists from KRICT. Calcium antagonistic properties of the compounds were studied in the isolated heart (Langendorff preparation), pulmonary artery (vasodilation), and in the papillary muscle (negative inotropic effect) of the guinea pig. Antihypertensive effect were also investigated after i.v. or oral administration in the SHR (spontaneously hypertensive rat). They produced a sigificant inhibition of Ca-induced contraction in the guinea pig pulmonary artery at the concentrations of above $10^{-8}M$. The negative inotropic effect of the electrically stimulated papillary muscle appeared from the concentration of $10^{-6}M$, which is about hundred times higer than the concentration of vasodilation effect. Left ventricular pressure also decreased from the concentration of $3\;{\times}\;10^{-6}M$ in KR-1008 and KR-3006 in the Langendorff heart preparations. Coronary flow rate increased from $10^{-6}M$ in KR-1008 and nicardipine and appeared no change in KR-30006. The antihypertensive effect of KR-1008 (EC 20: $2.9\;{\mu}g/kg$) was potent more than nicardipine (EC 20: $3.4\;{\mu}g/kg$) and than Kr-30006 (EC 20: $6.8\;{\mu}g/kg$) was, after i.v. bolus injection in the anesthetized SHR. The antihypertensive effect in the conscious SHR appeared 30 minutes after oral administration of 10 mg/kg and persisted 4 hrs in KR-1008 and 12 hrs in KR-30006. Heart rate tended to increase for 0.5-1 hr after oral administration of the test compounds.

• 공업화학
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• 제16권3호
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• pp.348-353
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• 2005

천연물 중에서 사자발쑥과 인진쑥, 홍경천, 청국장, 된장 추출물로 미백효과를 측정하였다. 쑥 10 g에 300 mL의 에탄올로 상온에서 3 h의 초음파 추출을 진행하였다. 추출물을 차례로 같은 양의 헥산, 클로로포름, 에틸아세테트로 분배과정을 거쳤다. 홍경천 5 g에 150 mL의 메탄올을 첨가하고 상온에서 12 h을 냉침하여 얻은 추출물을 액체 크로마토그래피를 통과하였다. 제조용 컬럼($3.9{\times}250mm$, $C_{18}$, $15{\mu}m$)을 통하여 두개 부분의 분획물을 획득할 수 있었다. 청국장과 된장은 60% 에탄올을 사용하여 추출하였다. 티로시나아제 억제활성과 멜라닌 억제효과로 미백효과를 측정하였다. 쑥의 경우 항산화효과에서는 인진쑥의 물층, 멜라닌 억제 효과에서는 사자발쑥의 헥산층, 인진쑥의 클로로포름층이 우수하였다. 홍경천 추출물은 in-vivo melanin production ratio assay에서 melanin-a 세포를 사용한 결과 미백효과는 알부틴보다 우수하였다. 청국장과 된장의 60% 에탄올 추출물은 미백효과를 나타내지 않았다.