• 한국전산유체공학회지
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• 제15권4호
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• pp.9-16
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• 2010

To alleviate NOx emission, a variety of approaches has been applied. In marine diesels, the application of SCR systems has been considered an effective exhaust aftertreatment method for NOx emission control. Most current SCR systems use a various catalyst for the reaction of ammonia with NOx to form nitrogen and water. In theory, it is possible to achieve 100% NOx if the $NH_3$-to-NOx ratio is 1:1. However, the reaction has a limited non-uniformity of the exhaust gas flow and ammonia concentration distribution. Therefore, it is necessary to investigate the optimum flow conditions. In order to achieve uniform flow at monolith front face, we are equipped with a various mixed devices. In this paper, it is presented that the mixed devices play an important role improvement of flow patterns and particle distributions of $NH_3$ by numerical simulation.

• 한국의류학회지
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• 제22권8호
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• pp.1011-1019
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• 1998

The natural dyestuff(squid ink) was manufactured from squid ink by boiling in 0.1% NaOH solution and powdering in freeze dryer. Cotton, wool, silk and nylon fabrics were dyed under several conditions using the manufactured squid ink to investigate the dyeability and color fastness. Dyeing was operated in acidic dyebath of pH 4 because the squid ink is anionic. Dyeabilities on wool, silk and nylon fabrics were good, especially silk fabrics were dyed deeper than others because of being amine group. But dyeability on cotton fabrics was low and developed with chitosan treatment. All the dyed fabrics showed excellent in color fastness to crocking and laundering. Also light fastness of them were excellent except nylon. The light fastness of dyed-nylon fabrics was as poor as grade 1, but they could be improved to grade 4 by aftertreatment with gallicacid. Useing the natural dyestuff-squid ink powder, we could execute whenever we want to dye fabrics in the adequate concentration. Dyeabilities were developed according to repeating times of dyeing and the increased dye concentration. We could recycle the wasting sources.

• 대한가정학회지
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• 제38권11호
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• pp.127-135
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• 2000

The natural dyestuff, grape skin dye was manufactured from grape skin by boiling in 0.1% HCI solution, eliminating the sugar and powdering in freeze dryer. Cotton, wool, silk and nylon fabrics were dyed under several conditions using the manufactured grape skin dye to investigate the dyeability and color fastness. Dyeing was operated in acidic dyebath of pH 4 because the grape skin is anionic. The color of dyed fabrics were affected on temperature of dyeing solution. Under 80$\^{C}$, the color of dyed fabrics were red or violet, but changed to brown in laundering. Above 100$\^{C}$, the color were brown and safe in laundering. Dyeabilities on wool, silk, and nylon fabrics were good, especially silk fabrics were dyed deeper than others. Dyeability was developed with concenturation of dyeing solution. All the dyed fabrics were excellent in color fastness to crocking and laundering. Light fastness was low to moderate. The light fastness of dyed nylon fabrics were as poor as grade 1, but they could be improved to grade 3∼4 by aftertreatment with gallic acid.

• 한국분무공학회지
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• 제9권1호
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• pp.15-20
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• 2004

The post injection effect to enhance aftertreatment devices' performance is essential to meet future stringent emission standards by controlling exhaust gas temperature and emission pollutants. The test has been made with commercial common rail diesel engine by post injection manipulation, to optimize exhaust gas temperature while guarantee low fuel penalty. The optimization was done at 1500, 2000 and 2500[rpm] for 2, 4[bar] condition which show low exhaust gas temperature. The main purpose of this test is dedicated to understand mechanism of exhaust gas temperature rise while optimizing

• 한국분무공학회지
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• 제20권1호
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• pp.20-27
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• 2015

Urea-SCR which is one of the aftertreatment technologies for reducing the NOx emission is widely used. An experimental study was performed to investigate urea decomposition under various thermo-fluid conditions, with different temperatures and velocities of inflow gas, and urea solution quantities. 40 wt. % aqueous urea solutions were used in this study. The inflow gas conditions were similar to the exhaust conditions of a large marine engine. The spray performance of urea solution injector was identical under all experimental conditions. The conversion efficiency of $NH_3$ was larger than that of HNCO under all experimental conditions, unlike for the theoretical thermolysis reaction.

• 한국염색가공학회지
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• 제15권5호
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• pp.301-309
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• 2003

Of the various types of dye that can be used to apply polyamide fibers, acid dyes and pre-metallised acid dyes are great in use so far. However, since these acid dyeings suffer from dye loss during laundering, recourse to an aftertreatment is usually necessary to achieve adequate fastness to washing. In the case of reactive dyes, the characteristically high washfastness of dyeings comes with the concomitant advantages of brightness and low environmental impact. Despite the obvious advantages, the commercialization of reactive dyes for polyamide fibers has not gained widespread success. In this context, the rewards for approach are likely to be considerable. Heterobifunctional reactive dyes were applied to polyamide fibers using various conditions. Optimum conditions and fixation were determined. The forms in which the vinylsulphone and hydrolyzed moieties were examined using HPLC-Mass. In addition, it was found that the extent of the washfastness secured, in terms of both change in color and staining of adjacent multifiber was being acceptable.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.145-151
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• 2012

New design of catalytic converter is proposed by optimization of DFSS (Design For Six Sigma) and DOE (Design Of Experiment) method which is based on taguchi matrix. As a result of the optimization of design of catalytic converter, this paper classifies Exhaust-downpipe shapes with 3 parameters to increase flow velocity uniformity of front catalytic substrate face from CFD results. after finishing with L9 Taguchi test matrix, it can be found the main effect of each design parameter of concept model, and optimal design level. in conclusion, it can be increase flow uniformity from 0.60 upto 0.80 with optimal diffuser shape for Turbo-charger.

• 한국염색가공학회지
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• 제19권2호
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• pp.1-6
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• 2007

In order to improve the light fastness of a natural colorant berberine, several natural antioxidants such as gallic acid, L-ascorbic acid, and ${\alpha}-tocopherol$ were applied by aftertreatment method. Even though the increase in light fastness of berberine colorant was not substantial, L-ascorbic acid was the most effective. It was considered that this improvement of the light fastness was due to high antioxidation action of L-ascorbic acid to colorant, which led very highly excited species of the colorant formed by photo-energy to return to the original stable state without being decomposed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1261-1266
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• 2004

Dielectric Barrier Discharge (DBD) in air, which has been established for the production of large quantities of ozone, is more recently being applied to a wider range of aftertreatment processes for HAPs (Hazardous Air Pollutants). Although DBD has high electron density and energy, its potential use as precharging nano and submicron particles are not well known. In this work, we measured I-V characteristics of DBD and estimated collection efficiency of the particles by DBD type 2-stage ESP. To examine the particle collection with various applied voltage waveforms of DBD for nano and submicron sized, bimodal particles were generated by a electrical tube furnace and an atomizer.

• 대한기계학회논문집B
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• 제31권2호
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• pp.167-172
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• 2007

A new method that optimizes a control of hydrocarbon (HC) addition to diesel exhaust gas for HC type DeNOx catalyst system has been developed. These catalysts are called the HC-DeHOx catalyst in this paper. The system using HC-DeNOx catalyst requires a resonable quantity of hydrocarbons addition in the inlet gas of the catalyst, because the HC concentration in a diesel engine is so low that the HC is not sufficient for NOx conversion. It is expected that this study offers a robust data developing HC injection system.