• 분석과학
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• 제13권6호
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• pp.766-774
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• 2000

유도결합 플라스마 원자방출분광법(ICP-AES)을 이용하여 몽골산 크롬철광의 성분을 분석하였다. 크롬철광을 용해시키기 위하여 과염소산-인산의 흔합산과 융제로서 $Na_2O_2$의 적용성을 검토한 결과 최적의 용해방법은 용융법이었다. 크롬광의 주성분과 미량성분을 ICP-AES로 정량할 때 과량의 Na가 측정파장에 미치는 영향을 조사하였다. Al, Cr, Fe 및 Mg과 같은 주성분원소의 경우 Na가 250 mg/L까지 영향을 받지 않았으나, Co, Ni, Ti, V 및 Zn과 같은 미량성분들은 Na가 1,250 mg/L인 경우 측정원소와 파장에 따라 방출선의 세기는 1-5% 정도 감소하였다. 본 방법의 정확도를 확인하기 위하여 중성자방사화분석으로 얻은 결과와 상대편차를 비교하였다. $Al_2O_3$, $Cr_2O_3$, FeO 및 MgO의 경우에는 FeO를 제외하고 상대편차가 5% 이내이며, Co, Mn, V 및 Zn의 경우에는 ~20-8% 범위였다.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2002년도 추계학술대회 논문집
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• pp.223-224
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• 2002

This study is motivated by the discrepancies found in previous studies that compared the observed photochemically reactive species in the marine boundary layer (MBL) with the model simulations. In particular, HCHO was underpredicted in PEM-Tropics (B) and overpredicted in TRACE-A, $H_2O$$_2$ overpredicted, $CH_3$OOH overpredicted, and $CH_3$OH significantly overpredicted (Thompson et al., 1993; Heikes et at., 1996; Davis et al., 1996; Jacob et al., 1996; Schultz et al., 1997; Suhre et al., 1998). (omitted)

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.344-351
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• 1996

Microorganisms growing alcoholic distillery wastes were isolated from soil. Of them, the selected strain EL-9 had a capability of accumulating poly-$\beta$-hydroxybutyrate (PHB) when grown in alcoholic distillery wastes. The strain EL-9 was identified as a genus Actinobacillus based on the morphological, cultural, and biochemical characteristics. The strain EL-9 was named temporarily as Actino- bacillus sp. EL-9. The optimal temperature and pH for cell growth of Actinobacillus sp. EL-9 were 30$\circ$C and 7.0, respectively. The optimal medium compositions for cell growth comprised glucose 2%, NH$_{4}$NO$_{3}$ 0.15%, Na$_{2}$HP0$_{4}$-12H$_{2}$O 0.25%, KH$_{2}$PO$_{4}$ 0.25%, MgSO$_{4}$4-7H$_{2}$O 0.15%, FeSO$_{4}$-7H$_{2}$O 0.005%, CaCl$_{2}$-2H$_{2}$O 0.003% and trace element solution 5m/l. To investigate the optimal conditions for PHB production, two-stage culture technique was used. The result showed that the optimal conditions for PHB production are identical those for cell growth. When propionic acid was added as a cosubstrate, PHB/HV copolymer was produced.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.99-103
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• 2008

Solvent extraction using salphen as a ligand has been investigated for the selective separation and determination of trace Fe(II) and Fe(III). A salphen ligand was synthesized, and solvent extraction variables, such as solution pH, the concentration of salphen, the type of organic solvent, auxiliary agents, oxidants and the effect of interference were optimized. Salphen is stable at pH 3-4, and Fe(III)-salphen complexes can be selectively extracted into an MIBK(4-methyl-2-pentanone) phase from an aqueous solution within this pH range. For the determination of the total amount of iron in 100 mL of aqueous solution, Fe(II) ions were completely oxidized using 0.05 mL of 3.5% H2O2 without side reactions. To evaluate its applicability, the proposed method was applied to determine trace Fe(II) and Fe(III) in several kinds of water samples. Reproducible results were obtained with RSD of less than 3.0%, and the recoveries for this reliability were obtained with 91-112%.

• 대한원격탐사학회지
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• 제15권3호
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• pp.253-266
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• 1999

ADEOS/IMG로 관측한 온도, 수증기, 오존의 분포를 1997년 (a)1월 10일, (b)1월 28일, (c)4월 2일, (d)6월 19일에 대하여 오산과 포항의 존데 관측 자료와 비교하였다. 전반적으로 오산의 자료와 비교한 (b)와 (d)의 경우는 대체로 존데 자료에 근접하였지만 포항의 자료와 비교한 (a)과 (c)의 경우는 상당한 차이를 보였다. 예를 들면 (b)와 (d)의 경우에 온도에 대한 RMSE 와 편의 분석 결과는 700~300 hPa 에서는 약 1~4 K, 그 이상의 고도에서는 4~5 K 이상의 편의를 나타내는데, 이것은 존데에 의한 관측 자료의 신뢰성 수준에 대한 논의도 함께 이루어져야 할 것으로 사료된다. 오존 분포에 대하여 동일한 분석을 시행한 레벨 2 5_6_4_4 버전의 결과는 50~60 hPa 이상의 상층을 제외하고는 그 차이가 0.3 ppmv 이하로 나타났다. 1997년 6월 19일에 한반도 상공의 5개 지점에서 관측한 IMG 자료중 레벨 2 5_6_4_4 버전의 결과는 온도, $H_2O$, $O_3$, CO의 연직 분포와는 달리 $CO_2$, $N_2$O, CH$_4$, HNO$_3$의 연직 분포는 관측지점이 달라짐에 따라 최대 농도가 나타나는 고도를 중심으로 그 차이가 크게 나타났다.

• 한국물환경학회지
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• 제36권4호
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• pp.314-321
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• 2020

This study evaluated the applicability of UV-AOP process using medium-pressure UV lamp and H₂O₂ to remove TOC and emerging micropollutants in the effluent from a sewage treatment plant. The UV lamp with higher output(1.6~8.0 kW) showed slightly higher amount of power in removing TOC of 1 mg/L(0.09 kWh/mg/L~0.11 kWh/mg/L), however it was found that there was no significant difference for each cases. In addition, under the condition that the H₂O₂ concentration is sufficient, as the power consumption of the UV lamp increases, the unit TOC removal concentration per unit H₂O₂ decomposition concentration also increases, resulting in effective removal of TOC. The removal rate of 7 new trace contaminants, such as antibiotics by the UV-AOP tested, was at least 89.4%, and the ability to remove the emerging micro pollutants in the process was very effective. But, it was judged that it could not be excluded that the probablity of transforming to oxidated by-product in the case of a low TOC removal efficiency. Depending on the operating conditions of the UV and H₂O₂ processes, a higher BOD concentration is found in the treated water than in the influent, and it is necessary to review the UV power and proper injection conditions of H₂O₂ to maintain the BOD concentration increase below a certain level.

• Bulletin of the Korean Chemical Society
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• 제17권7호
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• pp.625-630
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• 1996

The cobalt-substituted polyoxotungstate [(CoPW11O39)5-] has been used as a catalyst in olefin epoxidation and alkane hydroxylation reactions. The epoxidation of olefins by iodosylbenzene in CH3CN yielded epoxides predominantly with trace amounts of allylic oxidation products. cis-Stilbene was streoselectively oxidized to cis-stilbene oxide with small amounts of trans-stilbene oxide and benzaldehyde formation. The epoxidation of carbamazepine (CBZ) by potassium monopersulfate in aqueous solution gave the corresponding CBZ 10,11-oxide product. Other transition metal-substituted polyoxotungstates (M=Mn2+, Fe2+, Ni2+, and Cu2+) were inactive in the CBZ epoxidation reaction. The cobalt-substituted polyoxotungstate also catalyzed the oxidation of alkanes with m-chloroperbenzoic acid to give the corresponding alcohols and ketones. The presence of CH2Br2 in the hydroxylation of cyclohexane afforded the formation of bromocyclohexane, suggesting the participation of cyclohexyl radical. In the 18O-labeled water experiment, there was no incorporation of 18O into the cyclohexanol product when the hydroxylation of cyclohexane by MCPBA was carried out in the presence of H218O. Some mechanistic aspects are discussed as well.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.378-384
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• 1997

The ruminal solubility of copper (Cu), manganese (Mn), molybdenum (Mo), and zinc (Zn) in eight Philippine forages was studied. These forages were: 1) grasses: paragrass (Brachiaria mutica (Forsk.) Stapf), stargrass (Cynodon plectostachyum Pilger), and napiergrass (Pennisetum purpureum Schumach.); 2) creeping legumes: calopogonium or calopo (Calopogonium muconoides Desv.) and centrocema (Centrocema pubescens Benth.); 3) tree lequmes: gliricidia or kakawate (Gliricidia sepium (Jacq.) Walp.), leucaena or ipil-ipil (Leucaena leucocephala (Lam.) de Wit.), and sesbania or katuray (Sesbania grandiflora (L.) Poir). Nylon bags with samples were incubated for 0, 3, 6, 12, 24, 48 and 72h in three rumen cannulated sheep fed with timothy hay (Phleum pratense L.) at 2% body weight/d. The 0-h bags were washed with deionized water. There were species differences (p < 0.05) on the different solubilities of trace elements. At O-h incubation, the trend of solubility was Mo (54%) > Zn (43%) > Cu (38.7%) > Mn (29.5%). At 3-h incubation, all the elements except Mn had an average solubility above 50%. Combining particulate passage rate (1.9%/h) and various trace elements disappearance rates, the effective ruminal solubilization (ERS) of trace elements were computed. The ERS across species ranged from 44.6 to 89.9% for Cu, 29.9 to 84% for Mn, 66 to 95.1% for Mo, and 30.1 to 82.3% for Zn resulting to a trend of Mo > Zn > Cu > Mn.

• 한국분말재료학회지
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• 제22권6호
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• pp.391-395
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• 2015

We report on the successful fabrication of ZnO nanorod (NR)/polystyrene (PS) nanosphere hybrid nanostructure by combining drop coating and hydrothermal methods. Especially, by adopting an atomic layer deposition method for seed layer formation, very uniform ZnO NR structure is grown on the complicated PS surfaces. By using zinc nitrate hexahydrate $[Zn(NO_3)_2{\cdot}6H_2O]$ and hexamine $[(CH_2)_6N_4]$ as sources for Zn and O in hydrothermal process, hexagonal shaped single crystal ZnO NRs are synthesized without dissolution of PS in hydrothermal solution. X-ray diffraction results show that the ZnO NRs are grown along c-axis with single crystalline structure and there is no trace of impurities or unintentionally formed intermetallic compounds. Photoluminescence spectrum measured at room temperature for the ZnO NRs on flat Si and PS show typical two emission bands, which are corresponding to the band-edge and deep level emissions in ZnO crystal. Based on these structural and optical investigations, we confirm that the ZnO NRs can be grown well even on the complicated PS surface morphology to form the chestnut-shaped hybrid nanostructures for the energy generation and storage applications.

• Nutrition Research and Practice
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• 제8권2호
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• pp.220-226
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• 2014

BACKGROUND/OBJECTIVES: Arsenic, which causes human carcinogenicity, is ubiquitous in the environment. This study was designed to evaluate modulation of arsenic induced cancer by resveratrol, a phytoalexin found in vegetal dietary sources that has antioxidant and chemopreventive properties, in arsenic trioxide ($As_2O_3$)-induced Male Wistar rats. MATERIALS/METHODS: Adult rats received 3 mg/kg $As_2O_3$ (intravenous injection, iv.) on alternate days for 4 days. Resveratrol (8 mg/kg) was administered (iv.) 1 h before $As_2O_3$ treatment. The plasma and homogenization enzymes associated with oxidative stress of rat kidneys were measured, the kidneys were examined histologically and trace element contents were assessed. RESULTS: Rats treated with $As_2O_3$ had significantly higher oxidative stress and kidney arsenic accumulation; however, pretreatment with resveratrol reversed these changes. In addition, prior to treatment with resveratrol resulted in lower blood urea nitrogen, creatinine and insignificant renal tubular epithelial cell necrosis. Furthermore, the presence of resveratrol preserved the selenium content ($0.805{\pm}0.059{\mu}g/g$) of kidneys in rats treated with $As_2O_3$. However, resveratrol had no effect on zinc level in the kidney relative to $As_2O_3$-treated groups. CONCLUSIONS: Our data show that supplementation with resveratrol alleviated nephrotoxicity by improving antioxidant capacity and arsenic efflux. These findings suggest that resveratrol has the potential to protect against kidney damage in populations exposed to arsenic.