• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.191-196
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• 2006

The injection of ozone, produced by dielectric barrier discharge, into the exhaust gas gives rise to a rapid oxidation of NO that is the main component of nitrogen oxides($NO_x$) in most practical exhaust gases. Once NO is converted into $NO_2$, it on readily be reduced to $N_2$ in the next step by a reducing agent such as sodium sulfide and sodium sulfite. The reducing agents used ca also remove $SO_2$ effectively, which makes it possible to treat $NO_x\;and\;SO_2$ simultaneously. The present two-step process made up of an ozonizing chamber and an absorber containing a reducing agent solution was able to remove about 95% of the $NO_x$ and 100% of the $SO_2$, initially contained in the simulated exhaust gas. The formation of $H_2S$ from sodium sulfide was prevented by using a strong basic reagent(NaOH) together with the reducing agent. The removal of $NO_x$\;and\;SO_2$ was more effective for $Na_2S$ than $Na_2SO_3$.

• Analytical Science and Technology
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• v.17 no.5
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• pp.369-374
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• 2004

Plastic was decomposed with nitric acid after being carbonized by sulfuric acid. Then excess sulfuric acid and nitric acid was removed by evaporating and drying. Precipitated $SO{_4}^{-2}$ ion of $PbSO_4$ was resolved itself into $H_2S$ by HI in hydrochloric acid and was volatilized. Then $Pb^{+2}$ was dissolved and was measured by AAS and ICP. The test for reproducibility using PVC-Pb standard material (690-34610mg/kg) was conducted and the accuracy was more than 99.9% compared with the estimated concentration. The precision by AAS was 99.8% and that of ICP was 99.9%.

• Clean Technology
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• v.12 no.2
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• pp.87-94
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• 2006

The reduction of $SO_2$ to elemental sulfur by CO over a series of iron niobate with nominal Nb/Fe atomic ratios of 1/0, 10/1, 5/1, 1/1, 1/5, 1/10 and 0/1 was studied with a flow fixed-bed reactor. Strong synergistic phenomena in catalytic activity and selectivity were observed for the iron niobate catalysts, and the best catalytic performance was observed for the catalyst with Fe/Nb atomic ratio of 1/1. The active phase of the activated iron niobate catalysts was identified to be $FeS_2$ using XRD and XPS. Selective reduction of $SO_2$ by CO was followed by the COS intermediate mechanism.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.1
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• pp.103-111
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• 2021

The purpose of this study is to investigate the antibacterial efficacy of cotton and silk/rayon fabrics dyed with Saururus chinensis extract against antibiotic-resistant strains. The concentration of the concentrated dye in the Saururus chinensis extracts was 1.1% (o.w.f), and the liquor ratio was 1:10 at 30-70℃. The mordanting method was a post mordanting method. The concentration of Al2(SO4)3, CuSO4 5H2O and FeSO4 and7H2O mordant was 5% (o.w.f), and the liquor ratio was 1:40. In order to assess the antimicrobial activity of naturally dyed fabrics, Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 33591, was used by incubating it in Brain Heart Infusion Agar (BHA) including Oxacillin (2㎍/ml) and Fungizone (2.5㎍/ml) and Brain Heart Infusion broth (BHI; Detroit, MI, USA.) The investigation of the reduction of the rate of antibiotic-resistant strains to dyed cotton fabrics and silk/rayon fabrics revealed that Cu mordanting fabric has the highest antimicrobial effects, with the rate of 99.7%, and Fe mordanting fabric has the lowest, with 77.7%. Non-mordant cotton fabrics also show a high reduction rate of strains (94.6%). In the case of dyed silk/rayon fabrics, it indicates a high reduction in the rate of strains in all fabrics with non-mordant treatment (94.2%), Al mordanting (99.6%), and Cu and Fe mordanting(99.9%).

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.476-482
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• 2014

In this study, the characteristics of emulsified fuel and engine emissions were studied with engine dynamometer. Microexplosion took place in the combustion chamber. While combustion, emulsion fuel scattered to micro particles and it caused to smoke reduction. The heat produced from water vapour reduce the temperature of internal combustion chamber and it caused to inhibition of NOx production. It can be verified by the lower exhaust temperature of each ND-13 mode using emulsion fuel than that of MDO fuel. The NOx and smoke concentration were reduced by increasing water content in emulsion fuel. The power also decreased according to the increment of water content of emulsion fuel because emulsion fuel has low calorific value due to high water content than MDO. As a result of ND-13 mode test with 17% moisture content, it was achieved 24% reduction in NOx production, 76% reduction in smoke density, 11% reduction of $SO_2$ and 13% reduction in power loss.

• Journal of Space Technology and Applications
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• v.2 no.3
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• pp.187-194
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• 2022

Although the magnitude of the disturbance caused by the driving of the motor operated to secure the high-speed and precise directivity of the antenna is small, it acts as a major cause of impairing the image quality of the observation satellite, which requires precision directing performance. In order to acquire high-resolution image information through the improvement of the high-resolution observation satellite, proper vibration isolation and reduction design are required so that jitter generated when the directional antenna motor is driven is not transmitted to the main mission equipment. In this paper, the development process of the directional antenna vibration reduction device applied to real satellites and the effect of micro vibration reduction before and after application will be examined. This device was designed as a way to significantly improve the jitter problem by replacing only one gear in the directional antenna driving unit with a spring damper gear without any additional interface equipment. It was first applied and launched to a high-resolution earth observation satellite, and has been successfully operated so far.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.100-112
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• 2023

This study evaluated the contribution of carbon neutrality by calculating the carbon reduction amount and reduction intensity targeting the hydrogen pilot city and applying it to the carbon neutral reduction target. In the building sector, the reduction amount for 2030 was 10.8% on average. In addition, by 2050, the contribution to carbon neutrality of plan A was 14.1% on average, and the contribution to carbon neutrality of plan B was 15.1% on average. In the 2030 reduction amount of the transportation sector, the contribution to carbon neutrality was 138.4% on average. In addition, by 2050, the contribution to carbon neutrality in plan A was 82.5% on average, and the contribution to carbon neutrality in plan B was 74.9%. From the above research results, additional carbon reduction is possible when creating a hydrogen city, so it will be used as a basis of city-level carbon neutral model. It will also be used as a basis for technology development and investment promotion for various hydrogen supply methods in the future.

• Resources Recycling
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• v.33 no.1
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• pp.15-21
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• 2024

The demand for electric vehicles powered by lithium-ion batteries is continuously increasing. Recovery of valuable metals from waste lithium-ion batteries will be necessary in the future. This research investigated the effect of reaction temperature on the lithium recovery ratio from hydrogen reduction followed by water leaching from lithium-ion battery NCM-based cathode materials. As the reaction temperature increased, the weight loss ratio observed after initiation increased rapidly owing to hydrogen reduction of NiO and CoO; at the same time, the H₂O amount generated increased. Above 602 ℃, the anode materials Ni and Co were reduced and existed in the metallic phases. As the hydrogen reduction temperature was increased, the Li recovery ratio also increased; at 704 ℃ and above, the Li recovery ratio reached a maximum of approximately 92%. Therefore, it is expected that Li can be selectively recovered by hydrogen reduction as a waste lithium-ion battery pretreatment, and the residue can be reprocessed to efficiently separate and recover valuable metals.

• ETRI Journal
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• v.36 no.2
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• pp.293-300
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• 2014

As the system-on-chip (SoC) design becomes more complex, the test costs are increasing. One of the main obstacles of a test cost reduction is the limited number of test channels of the ATE while the number of pins in the design increases. To overcome this problem, a new test architecture using a channel sharing compliant with IEEE Standard 1149.1 and 1500 is proposed. It can significantly reduce the pin count for testing a SoC design. The test input data is transmitted using a test access mechanism composed of only input pins. A single test data output pin is used to measure the sink values. The experimental results show that the proposed architecture not only increases the number of sites to be tested simultaneously, but also reduces the test time. In addition, the yield loss owing to the proven contact problems can be reduced. Using the new architecture, it is possible to achieve a large test time and cost reduction for complex SoC designs with negligible design and test overheads.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.139-145
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• 2003

This study is to propose reduction effect of scour depth and a optimum size of circular collar through experimental analyses with various collar sizes. To do so, we carried out hydraulic model experiments. In the case of with considering the collar, the effect of reduction of scour depth increased according to the increase of collar size. When size of collar is 2 as the ratio of collar diameter(W) to pier diameter(D), scour depth is decreased about 67% and deposition height is increased about 70%. The optimal size of collar proposed in this study is W/D=2 by analyzing reduction effect of scour depth, size of scour hole, and deposition height.