• 한국염색가공학회지
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• 제13권5호
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• pp.1-1
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• 2001

As the basic study to investigate the mechanism of improvement in the dyeing fastness of natural dyes on silk fabrics the optical behavior of tannin solution, the optimal condition of tannin treatment and the changes of the physical structure of silk fabrics were studied in the treatment of tannin. Results obtained were as follows ; 1.The K/S values of tannin-treated silk fabrics were not changed by tannin content on silk fabrics but yellowing of tannin in treatment condition. 2. As the concentration of tannin was increased in its treating condition, the tannin content and K/S vague of tannin-treated silk fabrics were increased. 3. Because tannin gave rise to yellowing by hydrolysis and oxidation at high temperature, the higher tannin-treating temperature was, the lower the tannin content and K/S values of silk fabrics 4. The tannin content of silk fabric was higher in acidic treating condition and the highest K/S value was showed at pH 5. 5. As the tannin content of silk fabric was increased, the value of ζ -potential of it became negative. 6. As the tannin content of silk fabric was increased, the crystallinity and crystallite size of it were decreased. This meant that the fraction of amorphous region in the fibers increased. And the degree of orientation of it was decreased with the tannin treatment.

• 한국염색가공학회지
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• 제13권5호
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• pp.289-297
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• 2001

As the basic study to investigate the mechanism of improvement in the dyeing fastness of natural dyes on silk fabrics the optical behavior of tannin solution, the optimal condition of tannin treatment and the changes of the physical structure of silk fabrics were studied in the treatment of tannin. Results obtained were as follows ; 1 The K/S values of tannin-treated silk fabrics were not changed by tannin content on silk fabrics but yellowing of tannin in treatment condition. 2. As the concentration of tannin was increased in its treating condition, the tannin content and K/S vague of tannin-treated silk fabrics were increased. 3. Because tannin gave rise to yellowing by hydrolysis and oxidation at high temperature, the higher tannin-treating temperature was, the lower the tannin content and K/S values of silk fabrics 4. The tannin content of silk fabric was higher in acidic treating condition and the highest K/S value was showed at pH 5. 5. As the tannin content of silk fabric was increased, the value of $\xi$ -potential of it became negative. 6. As the tannin content of silk fabric was increased, the crystallinity and crystallite size of it were decreased. This meant that the fraction of amorphous region in the fibers increased. And the degree of orientation of it was decreased with the tannin treatment.

• 상하수도학회지
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• 제8권1호
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• pp.27-33
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• 1994

With the rapid industrialization, an ever-increasing quantity and kind of new organic compounds pose environmental problems due to their toxicity and physiological effect. However, research on the biodegradation of these compounds under anaerobic condition is very limited inspite of its efficiency and economical advantage. In this research, the pH effect on the ring cleavage of phenol under anaerobic condition was investigated, and the theory of phase separation was applied to the degradation of phenol for investigating the role of acidogenic bacteria. Results, obtained from biochemical methane potential(BMP) assay for 15.5 days of incubation, showed that acidic condition was more desirable for phenol degradation than alkaline condition. By both unacclimated methanogenic granular sludge and two mixed cultures, phenol was completely removed within six weeks of incubation with a gas conversion rate of over 86% of theoretical one. However, phenol was not degraded by unacclimated acidogenic culture, and thus it is considered as a syntrophic substrate. In case of phase separated biochemical methane potential(PSBMP) assay, in which acidogenic and methanogenic culture were seeded separately and consecutively, those that had been subjected to normal acidogens for 3 to 4 weeks showed higher gas production than those seeded with sterile or frozen culture.

• 한국염색가공학회지
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• 제16권5호
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• pp.1-7
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• 2004

Because acid dyes and reactive dyes require acidic condition for adsorption and alkaline condition for fixation respectively, it is difficult to dye nylon/cotton blends in one-bath one-step dyeing method. In this paper we tried to find out the suitable dye and dyeing condition for one-bath one-step dyeing of nylon/cotton blends. MNT type reactive dyes showed higher exhaustion on cotton as compared with MCT type dyes at neutral pH, which means that the MNT type reactive dyes are preferable for one-bath one-step dyeing method. The optimum condition for one-bath one-step dyeing of nylon/cotton blends was found to be pH 7. Wash fastness of fabrics dyed with half-milling type acid dyes was superior to that of fabrics dyed with levelling type acid dyes, when MNT type reactive dyes were used together.

• 한국세라믹학회지
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• 제24권4호
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• pp.343-348
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• 1987

The effects of salts such as aluminum sulfate as inorganic salt(2-4%), and sodium salts of citrate, tartrate, succinate, potassium tartrate and gelatin as organic salts(0.1%) on the formation of ${\alpha}$-calcium sulfate hemihydrate from by-product gypsum of phosphoric acid process under hydrothermal condition at 123$^{\circ}C$ and 133$^{\circ}C$ were investigated. Aluminum sulfate solution exhibited the catalystic effected on the crystallization of ${\alpha}$-calcium sulfate hemihydrate of which was assumed in the prismatic form, and organic salts solution exhibited little effect on the catalystic action to the crystallization, than inorganic salts. In the acidic solution with sulfuric acid(pH=2), needle like crystal of calcium sulfate hemihydrate was obtained. Hydrothermal process with aluminum sulfate solution also showed certain amounts of impurity removal such as phosphorus penataoxide from calcium sulfate hemihydrate.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.331-337
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• 2000

When microorganism is injected into porous medium such as soils, biomass retained in the pore. Bacteria within these microcolonies produced large amounts of exopolysaccharides and formed a plugging biofilm. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced and friction rate between soil aggregates increased. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrate and nutrient. Also, pore sand of before and after biofilm formation compared with scanning electron microscopy. Hydraulic conductivity of Sand and Poorly Graded Sand was decreased approximately 1/10∼1/100 after biomass inoculation and cultivation. Biofilm attached on soil aggregates is resistant to acidic or basic condition.

• 한국염색가공학회지
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• 제18권3호
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• pp.1-9
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• 2006

In order to dye polyester/cotton blend fabric by one-bath dyeing process with single disperse dye, a novel hetero-bifunctional bridge compound(DBDCBS) was synthesized and utilized. The DBDCBS was designed to contain two different reactive groups such as ${\alpha},{\beta}$-dibromopropionylamido and dichloro-s-triazinyl groups. The ${\alpha},{\beta}$-dibromopropionylamido group shows considerable reactivity towards amines or amino groups at acidic condition and high temperature. In contrast, the dichloro-s-triazinyl group has reactivity towards hydroxyl groups at alkaline condition and room temperature. In order to examine whether as a bridge the compound could combine dyes containing amino groups with cellulosic substrates, disperse dyes containing amino group were tried to dye the cotton fibers pretreated with the DBDCBS compound. By the results, polyester/cotton blends were dyed by one-bath dyeing process with single disperse dye,1,4-diaminoanthraquinone.

• 한국염색가공학회지
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• 제20권2호
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• pp.38-46
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• 2008

PET fabrics were cationized via photografting under continuous UV irradiation with a cationic monomer. The grafted PET was dyed with three acid dyes. Effect of dye concentration, dyeing time, temperature and pH on acidic dyeing of the cationized PET fabrics was assessed to find optimal dyeing condition. The cationized fabrics was successfully dyed at $75^{\circ}C$ under pH 5.5. However the dyeing sites of the grafted fabrics were nearly occupied above 5%owf dye concentration and the rapid exhaustion of the anionic dyes was observed. The dyeability of the cationized PET fabrics was increased proportionally with increasing percent grafting because of the introduction of ionic attraction between quaternary ammonium groups and acid dyes. Lower dyeability both at alkaline and pH 3 condition attributed to negative zeta potentials of the grafted fabrics and the reduced charge of the acid dyes respectively.

• 상하수도학회지
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• 제12권2호
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• pp.59-66
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• 1998

The feasibility of usage of sludge from water treatment plant and chalk from schools and institutes was investigated to remove the phosphorus in the lakes which induce the eutrophication every year. In this study phosphorus removal efficiencies of sludge and chalk were investigated by changing various factors. Higher phosphorus removal efficiency using larger particle size of chalk was observed which means that the surface area is not an important factor in removing phosphorus in aqueous phase. The proper shaking time and temperature were 2 hours and $25^{\circ}C$, respectively. The removal efficiency using sludge from water treatment plant was almost 100%, which is similar to those of CaO and $Ca(OH)_2$. It means that sludge can be reused in removing phosphorus. It was also found that chalk was better in removing phosphorus under alkaline condition and sludge was better under acidic condition. About 75% phosphorus removal efficiency was observed using sludge from the water sample in Lake Sihwa.

• 한국물환경학회지
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• 제24권6호
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• pp.670-675
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• 2008

Batch type adsorption and desorption tests were performed with different types (Powder, Granule) of Layered double hydroxides (LDHs) saturated with phosphate. The adsorption isotherm was approximated as a modified Langmuir type equation. The maximum adsorption capacity was 55 mg-P/g-LDH for powder type LDH, and 46 mg-P/g-LDH for granule type LDH. The highest phosphate desorption (79.6%) was obtained with 20% NaOH solution, whereas the desorption degrees were 4.8, 22.2% and 46.7% in the solutions of acidic condition (pH 4), 30% NaCl, and 3% NaOH, respectively. It was suggested that the optimal condition for the phosphate desorption from LDH was 30% NaCl + 3~6% NaOH solutions. The desorption characteristics of LDH was little influenced by adsorbent type.