• 한국응용과학기술학회지
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• 제25권2호
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• pp.168-174
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• 2008

This study is focused on the antimicrobial activity of cyanobacteria Microcystis aeruginosa by the reduction and oxidation reaction of copper and zinc alloy metal fiber filter. Cu/Zn ion is easily makes radicals with molecular hydroperoxide. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper and zinc alloy metal fiber is detected in the cyanobacteria solution as 0.5 ppm, and that of zinc ion is 0 ppm respectively. Zinc ion is figured to form a hydroxide in the cyanobacteria solution and precipitated to form a sludge. The concentration of chlorophyll-a in the cyanobacteria solution was proved to be the index of antimicrobial level of Microcystis aeruginosa.

• 한국식품영양과학회지
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• 제44권5호
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• pp.649-656
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• 2015

무지개송어 아가미상피세포를 이용하여 cortisol에 의해 유도된 세포 손상에 대항하는 아연의 보호 효과를 연구하였다. 24시간 동안 cortisol에 노출된 세포들은 농도 의존적으로 LDH 방출이 증가하였고, 세포 생존율은 감소하였다. 아연($100{\mu}M$ $ZnSO_4$) 처리에 의해 이와 같은 영향이 감소하였고, 아연은 cortisol에 의해 유도된 caspage-3 활성, 즉 apoptosis에 대항하여 세포를 보호하였다. Cortisol에 의해 유도된 세포 사멸, LDH 방출과 caspase-3 활성은 glucocorticoid 수용체의 길항제인 Mifepristone(RU-486) 처리에 의해 차단되었는데, 이것은 세포 손상이 cortisol과 관련이 있다는 것을 제안하였다. 더하여 cortisol에 의해 유도된 세포 손상 모델에서 MT, GST 그리고 G6PD와 같은 항산화 유전자 발현에 대한 아연의 영향을 연구했다. MTA, MTB, GST 그리고 G6PD mRNA 수준은 아연과 cortisol을 각각 단독 처리에 의해 그리고 아연과 cortisol을 동시 처리에 의해 증가하였다. 이와 같은 증가는 아연이나 cortisol 단독 처리보다는 $100{\mu}M$ $ZnSO_4$와 $1{\mu}M$ cortisol을 동시에 처리했을 때 MTA, MTB, GST 그리고 G6PD mRNA 수준이 더 높았다. 아연 처리에 의해 세포 내 자유 아연 농도가 증가하였고, 이와 같은 반응은 cortisol과 아연을 함께 처리했을 때 세포 내 자유 아연 농도가 더 증가하였다. 결론적으로 아연 처리는 간접적인 항산화 활성을 통해 cortisol에 의해 유도 세포독성 및 apoptosis를 저해하였다.

• 대한화학회지
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• 제13권2호
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• pp.141-147
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• 1969

Organophosphorous compounds can be reduced by zinc metal in acidic solution after alkaline hydrolysis. Although phosphates and phosphonates did not evolve any gas, dithioates did evolve hydrogen sulfide and phosphine, thionates and thiolates did evolve only hydrogen sulfide. The evolved gases were qualitatively detected by means of lead acetate and silver nitrate or mercuric bromide papers and determined by spectrophotometrically. The reduction mechanism and analytical method of dithioates were proposed.

• Bulletin of the Korean Chemical Society
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• 제17권4호
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• pp.314-321
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• 1996

Isoxazolidine derivatives 7 and 8 were synthesized from N-benzyl-C-(2-benzyloxyethyl)nitrones by 1,3-dipolar cycloaddition with ethyl crotonate. The isoxazolidine derivatives were converted to β-amino acid esters 9a and 9b by reduction with zinc in acetic acid. The β-amino acid esters were reacted with methylmagnesium bromide to give the 2-azetidinones (13a, 13b). The benzyl group of 2-azetidinones were removed by Birch reduction. The products were oxidized with PDC to give 3-[1-(t-butyldimethylsilyloxy)ethyl]-4-carboxymethyl-2-azetidinone derivatives (2a, 2c).

• 기술사
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• 제15권1호
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• pp.36-40
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• 1982

This study is to characterize Ago stability useful for manufacturing silver oxide button cell, and deter mined by test tube gassing evaluations and by cell expansion and further discuss en the effectiveness of pellet reduction treatments to obtain single plateau discharge Profile and relevent performance.

• Bulletin of the Korean Chemical Society
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• 제5권5호
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• pp.202-203
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• 1984

• Bulletin of the Korean Chemical Society
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• 제10권3호
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• pp.315-316
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• 1989

• 한국해양공학회지
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• 제25권1호
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• pp.32-38
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• 2011

Galvanized steel has gone through a chemical process to keep it from corroding. The steel gets coated in layers of zinc because rust will not attack this protective metal. For countless outdoor, marine, or industrial applications, galvanized steel is an essential fabrication component. The reduction of the corrosion rate of zinc is an important topic. In the past, a very popular way to reduce the corrosion rate of zinc was to use chemical conversion layers based on $Cr^{+6}$. However, a significant problem that has arisen is that the use of chromium salts is now restricted because of environmental protection legislation. Therefore, it is very important to develop new zinc surface treatments that are environmentally friendly to improve the corrosion resistance of zinc and adhesion with a final organic protective layer. In this study, a Urethane solution (only Urethane 20 wt.%; S-700) and an organic/inorganic solution with Si (Si polysilicate 10 wt.% + Urethane 10 wt.%; LRO-317) are used. Based on the salt spray test of 72 h, S-700 and LRO-317 had a superior effect for the corrosion resistance on EGI and HDGI, respectively.

• 열처리공학회지
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• 제36권1호
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• pp.22-32
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• 2023

In general, when scrap is dissolved in an electric arc furnace, the amount of electric furnace steel dust (EAFD) generated is about 1.5% of the scrap charge amount, and the electric furnace steel dust collected by the bag filter is charged into the Rotary Kiln or Rotary Hearth Furnace (RHF), and the zinc component is recovered as crude zinc oxide, at which time a clinker of Fe-Base is generated. In this research, first, for the efficient resource conversion of electric furnace steel dust, a reduction and roasting experiment was conducted and the reaction kinetics was examined. As a result of the experiment, it was observed that the reduction and roasting reaction was actively conducted in the range of 1100~1150℃, and melting occurred in the range of 1250℃. In the past, this clinker was widely used as a roadbed material for road construction and an Fe-Source for cement production, but in recent years, it has been mainly reclaimed due to strengthening environmental standards. However, landfill treatment is by no means a desirable treatment method due to environmental pollution caused by leachate, expensive landfill costs, and waste of Fe resources. Therefore, in order to more actively recycle the Fe component in the clinker, first of all the clinker was pulverized into an optimal particle size, and anthracite and binder (starch) were added to the magnetic material obtained by specific gravity and magnetic separation for briquet. As a experimental results, it was possible to efficiently separate clinker as Fe component and other slag component by specific gravity and magnetic force. As a results of loading and dissolving the manufactured briquet clinker in an electric arc furnace, it was observed that the unit of power and production yield were clearly improved and the carbon addition effect in molten metal was also somewhat.

• 한국분말재료학회지
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• 제31권2호
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• pp.163-168
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• 2024

As the demand for lithium-ion batteries for electric vehicles is increasing, it is important to recover valuable metals from waste lithium-ion batteries. In this study, the effects of gas flow rate and hydrogen partial pressure on hydrogen reduction of NCM-based lithium-ion battery cathode materials were investigated. As the gas flow rate and hydrogen partial pressure increased, the weight loss rate increased significantly from the beginning of the reaction due to the reduction of NiO and CoO by hydrogen. At 700 ℃ and hydrogen partial pressure above 0.5 atm, Ni and Li₂O were produced by hydrogen reduction. From the reduction product and Li recovery rate, the hydrogen reduction of NCM-based cathode materials was significantly affected by hydrogen partial pressure. The Li compounds recovered from the solution after water leaching of the reduction products were LiOH, LiOH·H₂O, and Li₂CO₃, with about 0.02 wt% Al as an impurity.