• 한국세라믹학회지
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• 제42권12호
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• pp.827-832
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• 2005

In this study, thin electrolyte layer was prepared by 8YSZ ($8mol\%$ Yttria-Stabilized Zirconia) slurry dip and sol coating onto the porous anode support in order to reduce ohmic resistance. 8YSZ polymeric sol was prepared from inorganic salt of nitrate and XRF results of xerogel powder exhibited similar results $(99.2\pm1wt\%)$ compared with standard sample (TZ-8YS, Tosoh Co.). The dense and thin YSZ film with $1{\mu}m$ thickness was synthesized by coating of 0.7M YSZ sol followed by heat-treatment at $600^{\circ}C$ for 1 h. Thin film electrolyte sintered at $1400^{\circ}C$ showed no gas leakage at the differential pressure condition of 3 atm.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.801-804
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• 2008

해안 구조물의 내구성 개선을 위해서는 염해저항성이 요구되므로 콘크리트의 수밀성 확보, 균열저항성 및 염소이온을 고정화하는 특성이 요구된다. 따라서 본 연구에서는 기존의 슬래그를 포함한 해안 콘크리트 배합에 유무기복합형 내구성 개선제(HD)를 적용하여 콘크리트의 시공성 및 강도발현에 미치는 영향과 함께 수축저항성이 및 내염해성에 미치는 효과를 파악하였다. HD의 적용에 따라 콘크리트의 수축저항성 및 내염해성이 개선되었으며, 특히 0.6% 적용 시 기존 슬래그를 포함한 배합보다 수축저항성 및 내염해성의 개선효과가 더욱 두드러진 것으로 확인되었다.

• 한국염색가공학회지
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• 제7권4호
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• pp.61-73
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• 1995

Inorganic salts have negative or positive effects on the rates of many chemical reactions and also the rates of acidic and alkaline hydrolysis of carboxylic esters. The direction of salt effects on the hydrolysis of ester depends on the charge of esters. It is expected that the rate of the alkaline hydrolysis of Poly(ethylene terephthalte)(PET), polymeric solid carboxytic polyester with carboxyl end group at the polymer end, is also influenced by inorganic salts. In the present work, to clarify the effect of divalent cations on the alkaline hydrolysis of PET, many salts with divalent cations like $MgCl_{2},CaCl_{2},SrCl_{2},BaCl_{2},$ were added to the aqueous alkaline solutions. Then PET was hydrolyzed with aqueous NaOH solution having many salts under various conditions. Some conclusions obtained from the experimental results were summarized as follows. Many salts with various divalent cations increased or decreased the reaction rate of alkaline hydrolysis of PET depending on their electrophilicity, hydration property, ability of ion pair formation, solubility, and the degree of interactions between divalent cations and anions, etc. The hydrolysis was interrupted in the order of $Ca^{+2} and was generally accelerated in the order of $Ba^{+2}. It was inferred from the increase in ΔS$^*$and the decrease in the ΔG$^*$that the divalent cations $Sr^{+2}$ and $Ba^{+2}$attracted by PET increased the collision frequency between carbonyl carbon and $OH^{-}$ion and then accelerated the reaction rate. $Mg^{+2}$and $Ca^{+2}$decreased the reaction rate because of their strong interaction with $OH^{-}$.

• Journal of Ginseng Research
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• 제28권4호
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• pp.201-206
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• 2004

본 시험은 약토시용량을 절약하기 위하여, 약토시용량을 기준 70(l/칸)보다 줄이고, 부족분을 추비로서 대체 가능성을 검토하였다. 약토시용량을 감소한 구(25.5l, 13.3l/칸)는 약토표준시 용구(70l/칸)보다 상토의 무기태질소, 인산, 칼리, 칼슘, 마그네슘 및 염류의 농도가 낮았으나 토양산도는 차이가 없었다. 2003년 5월29일 추비를 3l/칸 시용한 구에서는 각 처리구 모두 상토에서 무기태질소, 인산, 칼리, 칼슘, 마그네슘 및 염류농도가 증가되었다. 약토를 기비로 25.5l/칸 시용하고 추비를 준 처리구(25.5+SD)는 약토표준시용구(70l/칸)보다 6월에 상토에서 무기태질소, 칼리, 마그네슘 및 염류농도는 비슷하였으나 인산과 칼슘함량은 낮았다. 잎내 무기성분함량은 약토기비를 25.5(l/칸)시용하고 추비를 처리한구(25.S+SD)는 약토표준 시용구(70l/칸)보다 질소함량은 낮았으나 인산, 칼리, 칼슘 및 마그네슘함량은 차이가 없었다. 약토기비를 25.5(l/칸)시용하고 추비를 처리한 구(25.5+SD)는 약토표준시용구(70l/칸) 보다 경장이 짧고, 잎선단백화 현상이 $5{\%}$ 정도 더 발생되었으나, 출아율, 생존율, 잎노화율, 엽록소 함량, 경직경 및 엽면적은 차이가 없어서 약토시용량을 줄일 수 있는 경제적인 대안으로 가능성을 제시하고 있다.

• 한국토양비료학회지
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• 제35권1호
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• pp.47-58
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• 2002

남부지방을 중심으로 많은 시설재배지가 염류집적의 문제를 해결하기 위해 윤답전환체계로 운영되고 있으나, 윤답전환체계가 토양의 이화학적 특성 및 인산의 집적에 미치는 영향에 대한 연구가 거의 없었다. 경남 진주지역 윤답전환체계 운영시설재배지(RS) 22곳의 토양을 깊이별로 채취하여 이화학적 특성 및 인산의 분포특성을 인근 비윤답전환 시설재배지(NRS) 토양과 비교하였다. RS 표층토(Ap)의 전기전도도(EC)는 NRS에 비해 약 평균 약 $1.0dS\;m^{-1}$ 정도가 낮았으나 30cm 이하의 심층부에서는 RS의 EC값이 NRS에 비해 높아졌다. 깊이가 깊어질수록 두 형태간 EC값의 차이는 증가하여 세척된 염분이 상당부분 심층부로 이동되고 있음을 확인할 수 있었다. 기대와 달리 표층토의 유기물 함량은 RS가 NRS에 비해 약 $3g\;kg^{-1}$이 높았으며 이는 두 형태가 년간 유기물 시용량 차이에 기인된 것으로 해석되었다. 깊이가 증가 할수록 유기물 농도는 EC분포와 동일한 경향을 보여 윤답전환 과정중 단소의 유기물이 심층부로 이동되고 있음을 추정할 수 있었다. 전인산(T-P) 함량은 RS의 표층토가 NRS에비해 약 $850mg\;kg^{-1}$ 낮았으며, 이러한 경향은 심토까지 계속되었다. T-P의 약 90% 이상은 Inorganic P의 형태이었으며, Organic P와 Residual P가 저은 비율로 분포하였다. Inorganic P는 T-P에서와 같이 RS가 NRS에 비해 낮은 농도로 분포하였으며 깊이가 증가함에 따라 큰 폭으로 감소하였다. 이에 반해 Organic-P는 30cm 이상의 표층토에서는 RS가 NRS에 비해 낮은 농도로 분포하였으나 30cm 이하의 심층토에서는 RS가 NRS에 비해 높은 농도로 분포하였다. 특히 RS에서 Organic P는 NRS에서와 달리 깊이가 깊어짐에 따라 점점 증가하여 윤답전환지에서 인산이 상당 부분 Organic P의 형태로 이행되고 있음을 알 수 있었다. 표층토내 Extractable P는 Al-P와 Ca-P가 가장높은 비율로 존재하였으며, Fe-P와 수용성 P(W-P)의 순의 낮은 비율로 분포하였다. Ca-P와 W-P는 전 토양깊이에서 RS가 NRS에 비해 낮았으나 Al-P는 두 형태간 큰 차이가 없었다. 이에 반해 Fe-P는 RS가 NRS에 비해 높은 농도로 분포하였으며 20~40cm 사이에 가장 높은 농도로 분포하여 논토양 조건에서 영향을 받은 것으로 판단되었다. 결과적으로 윤답전환에 의한 약간의 T-P의 감소는 주로 W-P, Ca-P와 Organic P 형태로 주로 이동되었던 것으로 간접 해석되나 그 양은 기대했던 것에 비해 미미한 수준인 것으로 나타났다.

• 한국토양비료학회지
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• 제46권6호
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• pp.494-501
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• 2013

Two phosphate solubilizing Pantoea strains (P. agglomerans and P. rodasii) were employed in elucidating their phosphate solubilizing potential under different carbon and nitrogen sources, pH, temperature and salt conditions. Plant growth promoting characteristics such as ACC deaminase activity, indole acetic acid (IAA), HCN, ammonia, and siderophore production of the two strains were assessed in vitro. Potential applicability of the strains as bio-inoculants was also evaluated in pot experiments conducted under green house conditions. Phosphate solubilization measured as the amount of phosphorous released into the medium was recorded as 810 and $788{\mu}g\;ml^{-1}$ respectively by P. agglomerans and P. rodasii. Glucose at the rate of 2% was found be the best carbon source, while $(NH_4)_2SO_4$ was the best nitrogen source for both strains. Despite a slight decrease in phosphate solubilization observed at higher temperature, pH and salt concentrations, both strains could withstand against a range of temperature ($30-35^{\circ}C$), pH (7-9) and the presence of NaCl (up to 5%) without much compromising the phosphate solubilization. Different plant growth promoting traits (ACC deaminase activity, IAA, HCN, ammonia, and siderophore production) of the strains and their ability to promote the growth of green gram seedlings indicate that both strains possess high potential to be used as bio-inoculants.

• 공업화학
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• 제5권5호
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• pp.779-785
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• 1994

양이온 색소인 thionin(Th)과 음이온 계면활성제인 sodium dodecyl sulfate(SDS) 사이의 상호작용을 흡수 spectra로 고찰하였다. 임계미셀농도(critical micelle concentration, CMC)보다 훨씬 낮은 premicellar 영역(S/D=10, 80 및 160)에서 온도가 증가함에 따라 몰 흡광계수비가 증가하거나 감소함을 볼 수 있으며, S/D=160에서 Th-SDS계의 다분자 회합체가 생성하는 가장 안정한 온도 범위는 $60^{\circ}C$ 이하임을 알 수 있었다. 한편 Th-SDS계에 첨가한 무기염 및 유기용매의 농도가 증가함에 따라 ${\gamma}$-band와 J-band는 감소하나 ${\alpha}$-band는 오히려 증가하는 경향이 나타났다. 이들의 ${\alpha}$-band의 증가 순서는 무기염의 경우 $Cl^-$>$ClO{_4}{^-}$>$SO{_4}{^{2-}}$>$NO{_3}{^-}$로 나타나며, 유기용매인 경우는 2-propanol>ethanol>methanol>ethylene glycol로 나타남을 알 수 있다.

• 열처리공학회지
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• 제19권4호
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• pp.200-207
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• 2006

In addition to the basic properties of the base and top coating agents, corrosion resistance of non-chrome magni 565 coating and characteristics of coating film when coated to steel substrate were studied. The system had a good wettability at room temperature. Moreover, both the contact angle and surface tension were affected little by the viscosity of coating agent and surface roughness of the steel substrate. And the samples coated with optimal conditions showed a great corrosion resistance in salt spray test with 1500 hours or longer of initial appearance time of rust. The coating film was composed of overlapping layer of zinc and aluminium flakes, and the thickness of base coat increased with an increase of base coat viscosity. Based on the C-F peaks of 1,1-Difluoroethaen homo-polymer, it was thought that the base coat was an inorganic polymer bond layer. Meanwhile, the top coat showed C-F peaks of polytetrafluoroethylene with C-H peaks of phenol in FT-IR analysis. From the lower weight loss of base coat in TG analysis, it was thought that cross linking density of base coat was larger than that of top coat. It was thought that the small exothermic reactions observed in DSC curves were due to the thermosetting resins contained in the coating agents. Compared to the non-coated specimen, the coated sample showed more higher polarization resistance and corrosion potential with lower corrosion current density.

• Journal of Microbiology and Biotechnology
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• 제28권7호
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• pp.1156-1167
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• 2018

The aim of this study was to isolate and characterize lead (Pb)-solubilizing bacteria from heavy metal-contaminated mine soils and to evaluate their inoculation effects on the growth and Pb absorption of Brassica juncea. The isolates were also evaluated for their plant growth-promoting characteristics as well as heavy metal and salt tolerance. A total of 171 Pb-tolerant isolates were identified, of which only 15 bacterial strains were able to produce clear haloes in solid medium containing PbO or $PbCO_3$, indicating Pb solubilization. All of these 15 strains were also able to dissolve the Pb minerals in a liquid medium, which was accompanied by significant decreases in pH values of the medium. Based on 16S rRNA gene sequence analysis, the Pb-solubilizing strains belonged to genera Bacillus, Paenibacillus, Brevibacterium, and Staphylococcus. A majority of the Pb-solubilizing strains were able to produce indole acetic acid and siderophores to different extents. Two of the Pb-solubilizing isolates were able to solubilize inorganic phosphate as well. Some of the strains displayed tolerance to different heavy metals and to salt stress and were able to grow in a wide pH range. Inoculation with two selected Pb-solubilizing and plant growth-promoting strains, (i.e., Brevibacterium frigoritolerans YSP40 and Bacillus paralicheniformis YSP151) and their consortium enhanced the growth and Pb uptake of B. juncea plants grown in a metal-contaminated soil. The bacterial strains isolated in this study are promising candidates to develop novel microbe-assisted phytoremediation strategies for metal-contaminated soils.

• 한국입자에어로졸학회지
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• 제9권1호
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• pp.7-21
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• 2013

Twelve-hour size-resolved atmospheric aerosols were measured to determine size distributions of water-soluble organic carbon(WSOC) during daytime and nighttime, and to investigate sources and formation pathways of WSOC in individual particle size classes. Mass, WSOC, ${NO_3}^-$, $K^+$, and $Cl^-$ at day and night showed mostly bimodal size distributions, peaking at the size range of $0.32-0.55{\mu}m$(condensation mode) and $3.1-6.2{\mu}m$(coarse mode), respectively, with a predominant condensation mode and a minor coarse mode. While ${NH_4}^+$ and ${SO_4}^{2-}$ showed unimodal size distributions which peaked between 0.32 and $0.55{\mu}m$. WSOC was enriched into nuclei mode particles(< $0.1{\mu}m$) based on the WSOC-to-mass and WSOC-to-water soluble species ratios. The sources and formation mechanisms of WSOC were inferred in reference to the size distribution characteristics of inorganic species(${SO_4}^{2-}$, ${NO_3}^-$, $K^+$, $Ca^{2+}$, $Na^+$, and $Cl^-$) and carbon monoxide. Nuclei mode WSOC was likely associated with primary combustion sources during daytime and nighttime. Among significant sources contributing to the condensation mode WSOC were homogeneous gas-phase oxidation of VOCs, primary combustion emissions, and fresh(or slightly aged) biomass burning aerosols. The droplet mode WSOC could be attributed to aqueous oxidation of VOCs in clouds, cloud-processed biomass burning aerosols, and small contributions from primary combustion sources. From the correlations between WSOC and soil-related particles, and between WSOC and sea-salt particles, it is suggested that the coarse mode WSOC during daytime is likely to condense on the soil-related particles($K^+$ and $Ca^{2+}$), while the WSOC in the coarse fraction during nighttime is likely associated with the sea-salt particles($Na^+$).