• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.93-94
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• 2022

The presence of chloride (Cl-) ions in environments causes localized corrosion resulting decrease the durability of the structures. In this study, 5% Mg containing Al alloys (Al-5Mg) wire used vis-à-vis compared its corrosion resistance with pure Al in 3.5wt.% NaCl solution with exposure periods. Initially both wires exhibited identical open circuit potential (OCP) attributed to the presence of native oxide film on the surface but with the exposure periods it shifted towards active direction owing to the dissolution of oxide film. The pure Al continuously shifted the OCP towards active direction while Al-5Mg shows stabilization of OCP after 8 days of exposure. The OCP of Al-5Mg is slightly higher compared to pure Al wire owing to the activeness of Mg. The total impedance of the Al-5Mg alloy is almost three times greater than pure Al with exposure periods in 3.5 wt.% NaCl solution. It might be formation of Al-Mg LDH (layered double hydroxide) thin film onto the surface.

• KSBB Journal
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• 제17권6호
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• pp.586-589
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• 2002

Lipomyces starkeyi KSM 22는 덱스트라나아제와 아밀라아제 활성을 동시에 갖는 덱사메이즈를 생산한다. 1% (w/v)의 전분을 포함한 배지에 0.02% (w/v) 2-deoxy-D-glucose를 첨가한 경우, 넣지 않았을 때보다 약 2.5배의 증대된 효소 생산성을 보였으며, 0.5% (v/v) 글리세롤을 첨가한 경우 2.4배의 효소생산성을 보여 1% (w/v)의 덱스트란을 사용한 경우에 생산되는 덱사메이즈 양만큼의 생산성을 얻을 수 있었다. 정제된 효소와 효소 안정제로 사용이 가능한 혼합액을 4$0^{\circ}C$에서 3주간 방치 후 초기 활성과 비교하여 잔존하는 효소의 활성을 확인한 결과 25% (v/v) 글리세롤을 첨가했을 때 3주 후 덱스트라나아제의 활성으로 확인된 덱사메이즈의 활성은 초기의 90.9%가 유지되었고, 1% (v/v) 글리세롤에 50 mM CaCl$_2$와 KH$_2$PO$_4$를 첨가한 경우는 초기 활성의 73.4%가 유지되어 덱사메이즈 안정성에 효과가 있었다.

• 한국환경농학회지
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• 제33권2호
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• pp.78-85
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• 2014

BACKGROUND: Recent studies using various industrial wastes for heavy metal stabilization in soil were conducted in order to find out new alternative amendments. The acid mine drainage sludge(AMDS) contains lots of metal oxides(hydroxides) that may be useful for heavy metal stabilization not only waste water treatment but also soil remediation. The aim of this study was to investigate the applicability of acid mine drainage sludge for heavy metals stabilization in soils METHODS AND RESULTS: Alkali soil contaminated with heavy metals was collected from the agricultural soils affected by the abandoned mine sites nearby. Three different amounts(1%, 3%, 5%) of AMDS were applied into control soil and contaminated soil. For determining the changes in the extractable heavy metals, $CaCl_2$ and Mehlich-3 were applied as chemical assessments for metal stabilization. For biological assessments, lettuce(Lactuca sativa L.) and chinese cabbage(Brassica rapa var. glabra) were cultivated and accumulation of heavy metals on each plant were determined. It was revealed that AMDS reduced heavy metal mobility and bioavailability in soil, which resulted in the decreases in the accumulation of As, Cd, Cu, Pb, and Zn in each plant. CONCLUSION: Though the high level of heavy metal concentrations in AMDS, any considerable increase in the heavy metal availability was not observed with control and contaminated soil. In conclusion, these results indicated that AMDS could be applied to heavy metal contaminated soil as an alternative amendments for reducing heavy metal mobility and bioavailability.

• 대한화학회지
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• 제55권1호
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• pp.38-45
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• 2011

전이금속 이온인 수은(II) 및 은(I)에 대한 $\alpha$-케토안정화된 일리드화 인 $Ph_3P$=CHC(O) $C_6H_4$-X (X=Br, Ph)의 착물 반응 행동을 연구하였다. 수은(II) 착물 {$HgX_2$ [Y]} 2 ($Y_1$=4-bromo benzoyl methylene triphenyl phosphorane; X=Cl(1), Br(2), I(3), $Y_2$=4-phenyl benzoyl methylene triphenyl phosphorane; X=Cl(4), Br(5), I(6))는 $Y_1$ 및 $Y_2$를 $HgX_2$ (X=Cl, Br, I)와 각각 반응시켜 제조하였다. $\alpha$-케토안정화된 일리드화 인($Y_2$)의 은(I) 착물 [Ag$(Y_2)_2$] X(X=$BF_4$(7), OTf(8))는 이러한 일리드와 AgX(X=$BF_4$, OTf)를 아세톤에서 반응시켜 얻었다. 착물 (1)과 (4)의 결정구조를 고찰하였다. 일리드의 C-배위 이핵착물과 트랜스-구조의 착물$[Y_1HgCl_2]_2$. $CHCl_3$ (1) 및 $[Y_2HgCl_2]_2$ (4)를 형성하는 이들 반응에 대해 단결정 X-선 분석을 통해 고찰하였다. 모든 착물(1-3)은 IR, $^1H$ 및 $^{31}P$ NMR 뿐만아니라 $^{13}$CNMR을 통하여 확인하였다.

• Carbon letters
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• 제14권2호
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• pp.94-98
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• 2013

Isotropic pitch fibers were stabilized and carbonized for preparing carbon fibers. To optimize the duration and temperature during the stabilization process, a thermogravimetric analysis was conducted. Stabilized fibers were carbonized at 1000, 1500, and $2000^{\circ}C$ in a furnace under a nitrogen atmosphere. An elemental analysis confirmed that the carbon content increased with an increase in the carbonization temperature. Although short graphitic-like layers were observed with carbon fibers heat-treated at 1500 and $2000^{\circ}C$, Raman spectroscopy and X-ray diffraction revealed no significant effect of the carbonization temperature on the crystalline structure of the carbon fibers, indicating the limit of developing an ordered structure of isotropic pitch-based carbon fibers. The electrical conductivity of the carbonized fiber reached $3.9{\times}10^4$ S/m with the carbonization temperature increasing to $2000^{\circ}C$ using a four-point method.

• 한국식품조리과학회지
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• 제9권3호
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• pp.215-221
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• 1993

Bioactivity of the extract from various processed garlic was evaluated based on the inhibition of lipoxygenase(LPO), and the effect of some stabilizers on the bioactivity was investigated. Water, ethanol or chloroform extract of 30 min boiled garlic showed 75%, 76% or 70% inhibition, respectively, compared to extracts of fresh garlic. In pickled garlic, LPO inhibition decreased gradually during storage. Chloroform extract of 40 day-stored pickled garlic inhibited LPO by 77%, and even on 60th day storage it still retained inhibitory effect of 73%, compared to that of fresh garlic. Meanwhile, the powdered (freeze-dried) garlic showed more bioactivity(80%) than the other processed garlics, and moreover, the jrreversible/unstable components seem to be stabilized by freeze-drying. The optimum pH for stabilization of bioactive components in garlic macerate was pH 3 for 48 hr incubation and pH 11 for 6 hr incubation. In addition, the effect of NaCl was not so great, although but maximal stabilization was observed at 150 mM. Stabilizing effect of $\alpha$-tocopherol was markedly great, and at 6mM it showed 308% stabilizing effect after 48hr incubation. More stabilizing effect was observed at lower concentrations of ascorbic acid($\leq$0.6mM) than higher concentrations. The stabilizing effect of soybean oil was found to be remarkable only during initial period(6 hr) of incubation.

• Advances in Traditional Medicine
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• 제8권1호
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• pp.24-31
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• 2008

In the present investigation, we studied the effect of alcoholic extract of Moringa oleifera (M. oleifera) seed kernels on various experimental models of bronchial asthma. Significant (P < 0. 05) increase in preconvulsion time was observed due to pretreatment with M. oleifera when the guinea pigs were exposed to either acetylcholine (Ach) or histamine aerosol. This bronchodilating effect of M. oleifera was comparable to ketotifen fumarate. Spasmolytic effect of M. oleifera was also observed by dose dependent inhibition of ideal contractions induced by Ach, 5HT, histamine and $BaCl_2$. Alcoholic extract of M. oleifera produced significant dose dependent protection by egg albumin and compound 48/80 induced mast cell degranulation. Pretreatment with alcoholic extract of M. oleifera also decreased carrageenan induced rat paw edema, which was comparable to that of standard diclofenac sodium. Minimum inhibitory concentration for alcoholic extract of M. oleifera was low as compared to cold-water extract and hot water extract when antimicrobial activity was tested against various respiratory pathogens like Escherichia coli (E. coli), Staphylococus aureus (S. aureus) and pseudomonas aeruginosa (P. aeruginosa). Our data suggest that antiasthmatic activity of M. oleifera seed kernels may be due to its bronchodilator, anti-inflammatory, mast cell stabilization and antimicrobial activity.

• Carbon letters
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• 제21권
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• pp.51-60
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• 2017

Isotropic pitch-based fibers produced from coal tar pitch with the melt-blowing method were carbonized at temperatures ranging from 800 to $1600^{\circ}C$ to investigate their crystalline structure and physical properties as a function of the carbonization temperature. The in-plane crystallite size ($L_a$) of the carbonized pitch fiber from X-ray diffraction increased monotonously by increasing the carbonization temperature resulting in a gradual increase in the electrical conductivity from 169 to 3800 S/cm. However, the variation in the $d_{002}$ spacing and stacking height of the crystallite ($L_c$) showed that the structural order perpendicular to the graphene planes got worse in carbonization temperatures from 800 to $1200^{\circ}C$ probably due to randomization through the process of gas evolution; however, structural ordering eventually occurred at around $1400^{\circ}C$. For the carbonized pitch powder without stabilization, structural ordering perpendicular to the graphene planes occurred at around $800-900^{\circ}C$ indicating that oxygen was inserted during the stabilization process. Additionally, the shear stress that occurred during the melt-blowing process might interfere with the crystallization of the CPF.

• 한국지반공학회지:지반
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• 제2권3호
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• pp.5-14
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• 1986

점성토인 실트질점토(CL)와 사질토인 사질실트(SM)의 시료토에 Ca계의 소석회, Al계의 황산알미늄 첨가제로 안정처리한 결과 Ca계에 있어서는 실트질점토의 경우 알민산칼슘수화물과 탄산칼슘이 반응생성 되었으며 사질실트의 경우에는 탄산화알민산칼슘수화물과 탄산칼슘이 반응생성 (반도생성)되었고 Al계의 첨가 처리 경우에서는 실트질점토와 사질실트 모두에서 산화암미늄이 생성되어 있음을 X-선 회절분석에 의한 구조적 특성을 비교함으로써 확인되었고 이들 안정처리 효과로서 일축압축강도가 Ca계의 경우는 크게 증가하였으나 Al계의 경우에서는 거의 증가가 없었다.

• 자원리싸이클링
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• 제16권2호
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• pp.32-39
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• 2007

폐자동차 ASR의 소각재를 대상으로 물리화학적 물성측정 및 리싸이클링을 위한 경량재료 제조실험을 수행하였다. 대상시료는 국내 ASR 소각장에서 채취한 바닥재 2종류와 비산재 4종류이었으며, 이들의 주요 성분 및 입도분석을 실시하고 공정시험법에 의한 중금속 용출량을 조사하였다. 또한, 비산재인 boiler ash를 원료로 하여 경량물질과 무기바인더를 첨가하여 성형 및 소성하는 방법으로 경량재료를 제조하였다. 바닥재에 Cu 함량이 3wt% 내외로 상당히 높은 것으로 나타나 Cu의 사전 분리가 필수적인 것으로 나타났다. 수용성물질을 많이 함유한 SDR(semi-dry reactor) ash와 Bag filter ash의 주성분은 각각 $CaCl_2{\cdot}Ca(OH)_2{\cdot}H_2O$ 및 $CaCl_2{\cdot}4H_2O$인 것으로 나타났다. boiler ash를 원료로 사용하여 제조한 경량재료 시편의 경우 중금속 용출이 크게 감소하였으며, 그 이유는 중금속 성분이 불용성 화합물천 안정화 또는 encapsulation 되었기 때문으로 판단되었다.