Nanostructured cobalt materials have recently attracted considerable attention due to their potential applications in high-density data storage, magnetic separation and heterogeneous catalysts. The size as well as the morphology at the nano scale strongly influences the physical and chemical properties of cobalt nano materials. In this study, cobalt nano particles synthesized by a a polyol process, which is a liquid-phase reduction method, were investigated. Cobalt hydroxide (Co(OH)2), as an intermediate reaction product, was synthesized by the reaction between cobalt sulphate heptahydrate (CoSO4·7H2O) used as a precursor and sodium hydroxide (NaOH) dissolved in DI water. As-synthesized Co(OH)2 was washed and filtered several times with DI water, because intermediate reaction products had not only Co(OH)2 but also sodium sulphate (Na2SO4), as an impurity. Then the cobalt powder was synthesized by diethylene glycol (DEG), as a reduction agent, with various temperatures and times. Polyvinylpyrrolidone (PVP), as a capping agent, was also added to control agglomeration and dispersion of the cobalt nano particles. The optimized synthesis condition was achieved at 220˚C for 4 hours with 0.6 of the PVP/Co(OH)2 molar ratio. Consequently, it was confirmed that the synthesized nano sized cobalt particles had a face centered cubic (fcc) structure and with a size range of 100-200 nm.

The effect of ferrous/ferric molar ratio on the formation of nano-sized magnetite particles was investigated by a co-precipitation method. Ferrous sulfate and ferric sulfate were used as iron sources and sodium hydroxide was used as a precipitant. In this experiment, the variables were the ferrous/ferric molar ratio (1.0, 1.25, 2.5 and 5.0) and the equivalent ratio (0.10, 0.25, 0.50, 0.75, 1.0, 2.0 and 3.0), while the reaction temperature (25˚C) and reaction time (30 min.) were fixed. Argon gas was flowed during the reactions to prevent the Fe2+ from oxidizing in the air. Single-phase magnetite was synthesized when the equivalent ratio was above 2.0 with the ferrous/ferric molar ratios. However, goethite and magnetite were synthesized when the equivalent ratio was 1.0. The crystallinity of magnetite increased as the equivalent ratio increased up to 3.0. The crystallite size (5.6 to 11.6 nm), median particle size (15.4 to 19.5 nm), and saturation magnetization (43 to 71 emu.g-1) changed depending on the ferrous/ferric molar ratio. The highest saturation magnetization (71 emu.g-1) was obtained when the equivalent ratio was 3.0 and the ferrous/ferric molar ratio was 2.5.

유채 (Brassica napus L.)에서 황 공급수준에 따른 글루타치온 함량의 변화가 황 흡수 및 동화관련 효소 활력에 미치는 영향을 규명하고자, 농도를 4수준 (0, 0.1, 1.0 및 2.0 mM)으로 25시간 처리 한 후 식물조직 내 글루타치온 함량을 측정하고, 흡수, ATP sulfurylase (ATPS) 및 O-acteylserine (thiol) lyase (OASTL) 효소 활력과의 상관관계를 분석하였다. 흡수는 황 공급수준에 따라 평

Methods of producing hydrogen include steam reforming, electrochemical decomposition of water, and the SI process. Among these methods, the Sulfur iodine process is one of the most promising processes for hydrogen production. The thermochemical sulfur-iodine (SI) process uses heat from a high-temperature-gas nuclear reactor to produce H2 gas; this process is known for its production of clean energy as it does not emit CO2 from water. But the SI-process takes place in an extremely corrosive environment for the materials. To endure SI environments, the materials for the SI environment will have to have strong corrosion resistance. This work studies the corrosion resistances of the Fe-Si, Ni-Ti and Ni Alloys, which are tested in SI-process environments. Among the SI-process environments, the conditions of boiling sulfuric acid and decomposed sulfuric acid are selected in this study. Before testing in boiling sulfuric acid environments, the specimens of Fe-4.5Si, Fe-6Si, Ni-4.5Si, Ni-Ti-Si-Nb and Ni-Ti-Si-Nb-B are previously given heat treatment at 1000˚C for 48 hrs. The reason for this heat treatment is that those specimens have a passive film on the surface. The specimens are immersed for 3~14 days in 98wt% boiling sulfuric acid. Corrosion rates are measured by using the weight change after immersion. The corrosion rates of the Fe-6Si and Ni-Ti-Si-Nb-B are found to decrease as the time passes. The corrosion rates of Fe-6si and Ni-Ti-Si-Nb-B are measured at 0.056 mm/yr and 0.16 mm/yr, respectively. Hastelloy-X, Alloy 617, Alloy 800H and Haynes 230 are tested in the decomposed sulfuric acid for one day. Alloy 800H was found to show the best corrosion resistance among the materials. The corrosion rate of Alloy 800H is measured at -0.35 mm/yr. In these results, the corrosion resistance of materials depends on the stability of the oxide film formed on the surface. After testing in boiling sulfuric acid and in decomposed sulfuric acid environments, the surfaces and compositions of specimens are analyzed by SEM and EDX.

Elution effect was studied by the reactions between Electric arc furnace(EAF)dust and conc. or dil. sulfuric acid for the purpose of recoverying of the useful metals afterwards. The methods of mixing with acids and EAF dust for the elutions were depend on the ratios of acid/EAF dust. Experimental results showed that increased the ratios of sulfuric acids, decreased the elution effects are on the Zn, Fe and Mn, and conc. sulfuric acid showed higher elution effects than dil. sulfuric acids for the all metals. But in case of Pb, dil. sulfuric acid showed higher elution effects than conc. sulfuric acids conversely. Furthermore, the reason of the extreamly low quantities of eluted Pb is caused by the low solubilities by sulfuric acids compared to the other metals, as the results of the insoluble Pb is removed by the process of filtering.

Various anti-scattering agents for suppression of dust scattering at waste depository were compared in this study. Based on the price, easy of usage, and no toxicity, 1% of Al2(SO4)3 was selected as surface hardening agents. Only lower than 2% of total weight were flied when wind speed was monthly maximum velocity during 1 hr. These results were quite good with comparison of S anti-scattering agents which was made by C company in Korea. When Al2(SO4)3 was spread, the surface waste became hard therefore the effect of suppression of scattering dust was long lasting. It was recommend that 2% of Al2(SO4)3 was spread to keep suppression of scattering dust when sudden gust of wind such as natural disaster was occurred.

The chemical formula of magnetite (Fe3O4) is FeO·Fe2O3, t magnetite being composed of divalent ferrous ion andtrivalent ferric ion. In this study, the influence of the coexistence of ferrous and ferric ion on the formation of iron oxide wasinvestigated. The effect of the co-precipitation parameters (equivalent ratio and reaction temperature) on the formation of ironoxide was investigated using ferric sulfate, ferrous sulfate and ammonia. The equivalent ratio was varied from 0.1 to 3.0 andthe reaction temperature was varied from 25 to 75. The concentration of the three starting solutions was 0.01mole. Jarosite wasformed when equivalent ratios were 0.1-0.25 and jarosite, goethite, magnetite were formed when equivalent ratios were 0.25-0.6. Single-phase magnetite was formed when the equivalent ratio was above 0.65. The crystallite size and median particle sizeof the magnetite decreased when the equivalent ratio was increased from 0.65 to 3.0. However, the crystallite size and medianparticle size of the magnetite increased when the reaction temperature was increased from 25oC to 75oC. When ferric and ferroussulfates were used together, the synthetic conditions to get single phase magnetite became simpler than when ferrous sulfatewas used alone because of the co-existence of Fe2+ and Fe3+ in the solution.

유채(Brassica napus L.)에서 외생적 황 공급이 흡수와 동화에 대한 영향을 알아보고자 농도를 세가지 수준(1 mM , 대조구; 0.1mM , 결핍; 0 mM , 무공급)으로 25시간 처리한 후 식물조직내에서의 농도, ATP sulfurylase와 APS reductase 활성을 측정하였다. 의 흡수와 식물조직내에서의 의 농도는 결핍과 무공급 조건하에서 현저하게 감소하였다. ATP sulfurylase 활성은 외부 황 공급의 감소에 따라 증가

The acute and subacute toxicities of copper sulfate were evaluated in zebrafish (Brachydanio rerio). Dipping of fishes for acute toxicity was performed for a period of 24 h, and TLm24h value (median tolerance limit = LC50) was 1.36 ppm. Clubbing of gill filaments due to severe epithelial hyperplasia of gill lamella were oberved. And epithelial edema, fusion and necrosis of renal tubules were presented. The most significant change was mild epithelial hyperplasia of gill lamella in subacute toxicity test which fishes were exposed to 0.15 ppm of copper sulfate for 1 week.

A Fe(OH)2 suspension was prepared by mixing iron sulfate and a weak alkali ammonia solution. Following this, iron oxides were synthesized by passing pure oxygen through the suspension (oxidation). The effects of different reaction temperatures (30˚C, 50˚C, 70˚C) and equivalent ratios (0.1~10.0) on the formation of iron oxides were investigated. An equilibrium phase diagram was established by quantitative phase analysis of the iron oxides using the Rietveld method. The equilibrium phase diagram showed a large difference from the equilibrium phase diagram of Kiyama when the equivalent ratio was above 1, and single Fe3O4 phase only formed above an equivalent ratio 2 at all reaction temperatures. Kiyama synthesized iron oxide using iron sulfate and a strong alkali NaOH solution.

간척지에서 유안과 황산칼리비료의 시용이수수 수단그라스 교잡종의 수량성, 사료가치 그리고 토양 염류도에 미치는 영향을 구명하기 위해서 년 동안 충남 당진에 위치한 대호간척지에서 시험한 결과, 평균 토양 염류도는 요소를 시용한 표준시비구(T2)에 비해 유안을 시용한 구(T3, T4, T5)에서 낮게 나타났으며, 염화칼리 대신 황산칼리를 시용한 T6구가 가장 낮게 나타났다. 생초수량은 요소를 시용한 표준시비구(T2)에 비해 유안을 시용한 T3, T4, T5구

Most of cosmetics are emulsion products that contain the source of nutrition vegetable oil, mineral oil, natural extract and carbohydrate etc. There are many possibilities to be contaminated by microbials. We investigated the effect of antimicrobial and minimum inhibitory concentration(MIC) with thiamine dilauryl sulfate(TDS), which was prepared to use cosmetic lotion formulation. Staphylococcus aureus(S. aureus) and Escherichia col(E. coli) were used as test organism. MIC value of TDS was determined aganist microorganism for the growth inhibition by concentration of TDS. From the MIC results, antimicrobial effect of TDS was generally more effective to gram positive than gram negative. Antimicrobial effect with pH value against some microorganism appeared in the following order : pH 5 > pH 6 > pH 7. It showed strong antimicrobial activities against S. aureus, and weak antimicrobial activities against E. coli. If it was possible to determine the formulations with TDS, it would be effective to reduce the artificial preservatives.

The capacity and long life of gel electrolyte batteries is connected with gas recombination producting PbO2 and Pb electrode. We prepared with sulfuric acid gel electrolyte to know gel characteristics per density to assemble valve regulated lead-acid (VRLA) batteries. We studied on actions of sulphuric acid gel electrolyte by measuring electrolyte dispersion using Brewster-angle microscope (BAM), charge-discharge cycle, and electrode structure using scanning election microscope (SEM). Sulphuric acid density 1.210 showed excellent gel dispersion in sol condition, electrode condition after fifty cycles in this study.

10년 이상 된 방사능오염 토양에서 동전기적 방법에 의한 Cs과 Co의 제염효율을 높이기 위해 HSO과 시트르산을 첨가제로 사용했다. 동전기 토양복원 컬럼의 방출수 평균속도는 2.0 cm/min이고, 10일 동안 방출된 토양폐액의 부피는 컬럼의 3.6 공극부피다. 10일간 Cs 의 제거효율이 54%에 불과한 반면에, Co는 97%나 제거되었다. 이것은 Cs의 흡착평형계수가 Co 보다 크기 때문이라고 생각된다. 본 연구에서 제시한 수학적 모델에 의한 컬럼 잔류 오염도는 실험 오차 범위에서 실험결과와 잘 일치하였다.