• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.399-410
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• 1991

New separation process was developed for the preparation of storage-stable liquid dyes. The extent of aggregation of dye molecules was measured with respect to storage time of liquid dyes under different salt environments. Hollow-fiber membranes were modified by immobilization of inorganic crystals onto the surface of membrane. Using surface-treated membranes, counter diffusion technology was introduced to selectively remove salts from dye solution. The separation factors were 10-700, and the loss of dye molecules was less than 0.4 %. Membrane permeabilities for sodium ions($U_{M,Na}$) and dye molecules($U_{M,Dye}$) were found to be 2.75 and $0.72l/m^2/hr$, respectively, in the case of surface-treated membranes. The effects of various operating parameters on desalting efficiency were also investigated.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.141-147
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• 2017

The purpose of this study is to develop an inorganic filling adhesive using MKP and borax based on Dead-burn magnesia and fly ash. First, basic experiments was conducted to derive the proper addition rate of MKP. And this experiment was carried out according to addition ratio of borax. The test items are measured for pot life, flexural strength, compressive strength, adhesive strength, tensile strength, ratio of temperature change, ratio of hardening shrinkage, radon gas and formaldehyde emission. As a result, the proper addition rate of phosphate was 35%. The pot time is about 10minutes, 15minutes and 25minutes according to addition rate of borax. The flexural strength and compressive strength were obtained at 12hours for minimum flexural strength of 8.0MPa and minimum compressive strength of 31.0MPa. The tensile strength was the least 4.1MPa, and the ratio of hardening shrinkage was maximum 2.4% and ratio of heat change was maximum - 0.3%, which satisfied all of the quality standards of 'KS F 4923' (epoxy resin for repairing concrete structures). Both Radon gas and formaldehyde emission was not detected.

• Journal of the Korea Institute of Building Construction
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• v.19 no.4
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• pp.289-297
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• 2019

Epoxy resin adhesives are currently used as adhesives in buildings. Epoxy resin adhesives, which are organic materials, generate harmful substances when producing adhesives, and toxic substances are high in the residential space after installation. In addition, a large amount of carbon monoxide generated from organic materials in the case of a building fire leads to personal injury. This study evaluates the feasibility of inorganic adhesives using pure inorganic materials such as magnesia, phosphate, and borax as inorganic adhesives to replace existing organic adhesives. As a result of the experiment on the selection of adequate phosphate and the characteristics of the addition rate of borax used as a retarder, the potassium phosphate monobasic was obtained as a suitable phosphate and the characteristics according to the borax addition rate were compared with the quality standard of KS F 4923 The hardening shrinkage and heat change rate satisfied the quality standards. The tensile strength was satisfactory when the borax addition rate was 4% or more, but the adhesive strength did not meet the quality standards. Further studies are needed to improve adhesion strength.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.312-317
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• 2005

Chemical composition, and mineral and heavy metal contents of Yeomsan and Baekso sun-dried salts (1-5-year-old) were determined. Moisture contents (Yeomsan, 6.07-17.02%; Baekso, 4.29-16.15%) and pH (Yeomsan, 5.92-6.31; Baekso, 5.52-6.23) decreased as age of salts increased, while NaCl contents (Yeomsan, 80.35-92.74%; Baekso, 81.06-94.58%) increased with increasing storage period of salts. Older salts had lower content of water-insoluble matters. Nitrate content was not affected by aging of salts, whereas nitrite content was lower in older salts. Sulfate content of sun-dried salt decreased with aging of salt. Average concentrations (ppm wet weight) of major minerals in Yeomsan and Baekso sun-dried salts were: Mg, Mg, 1002-119; K, 1062-3411; Ca, 1503-3437; Li, 25-101; Ge, 8.35-0.21; Si, 43.99-6.48; and Mn, 6.79-1.55. Mineral content generally decreased with salt aging. Among heavy metals, Hg was not detected in all salts, and Cd (0.02-0.04ppm) was not affected by storage period. Pb was not detected in 5-year-old salts. Older salts showed brighter color than younger ones.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.229-233
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• 2016

In this study, an efficient ultrasound-assisted liquid-liquid extraction process was developed for recovering of paclitaxel from plant cell cultures. The optimal ultrasonic power and operating time were 250 W and 15 min at fixed ratio of bottom phase, methylene chloride to top phase, MeOH (25%, v/v). Under the optimal conditions developed in the present method, most of the paclitaxel (~92%) was recovered from crude extract by a single extraction step. Due to the synergistic effect of ultrasound by the addition of inorganic salt, an appropriate inorganic salt concentration and the ultrasonic power were found to be required for the effective recovery of paclitaxel using ultrasound-assisted liquid-liquid extraction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.475-488
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• 1995

In order to see the seasonal variation of nutrients and the limiting factors to the primary production in Deukryang Bay, both dissolved inorganic nutrients and salinity were measured in the surface waters during the periods from July 1992 to March 1993. The mean value of salinity was the lowest in ?all and the highest in early spring. Dissolved inorganic nitrogen (DIN) was the highest in winter and the lowest in summer. However, both phosphate and silicate were the highest in summer and the lowest in fall. Salinity was generally higher in the outer region than in the inner region of the bay.DIN content was nearly depleted (less than $2{\mu}M$) in summer. From fall to spring, DIN content was nearly depleted in the inner region and relatively high in the outer region of the Day. Phosphate was the highest in summer showing an opposite distribution pattern to salinity, and it was nearly depleted (less than $0.1{\mu}M$) in fall and winter. In spring, however, phosphate content was slightly high in the outer region. Silicate content showed an opposite distribution pattern to salinity in summer. in other seasons, However, the distribution pattern of silicate was similar to the salinity. DIN seemed to be a limiting factor for the primary production at all area of the bay in summer and at the inner region in other season. However, phosphate seemed to be a limiting factor at all area of the bay in fall and winter and at the inner region in spring. Silicate may limit the production of diatoms at the inner region of the bay in winter and spying. Both phosphate and silicate showed a good inverse relationship with salinity in summer, which indicates inputs of these nutrients from the freshwater runoff. In the other seasons, both nitrate and silicate showed a positive linear relationship with salinity in the outer region of the bay, suggesting that these two nutrients were mainly supplied by the inflow of the offshore costal water which had high nitrate content associated with vertical mixing.

• Food Science and Preservation
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• v.18 no.6
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• pp.993-997
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• 2011

The aims of this research were to determine the proximate composition of various salts and to compare two digestion methods (direct digestion without heating, and microwave digestion) for the determination of the main mineral contents of various salts. Twelve salt samples were divided into three groups of four samples each (imported, Korean gray, and Korean white salts). As a result, the NaCl contents of the Korean white, Korean gray, and imported salts were 85.1, 89.3, and 91.3%, respectively. The salts in the three groups were analyzed for their main mineral contents via AAS. The sodium (Na) content of the Korean white salt was found to be slightly lower than that of the imported salt while the magnesium (Mg) and potassium (K) contents of the Korean white salt were found to be higher than those of the imported salt. The mineral composition (% Na:Mg) obtained using microwave-assisted digestion procedures, and the other dissolutions for the subsequent sample analysis, were 89:1 (for both the imported and Korean gray salts) and 82:3 vs. 81:3 (Korean white salt), respectively. The data regarding the mineral contents and composition of the sun-dried salts obtained through the analysis method of wet digestion and the dissolution procedure were compared, and no significant difference was found between the two datasets. Consequently, in this paper, a direct dissolution procedure is suggested for the analysis of the mineral composition of salt.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.907-912
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• 2008

In order to reduce the availability of dissolved inorganic phosphorus in surface water, lakes, and estuaries, black shale and zero valent iron can be used as reacitve materials. Sorption of phosphate to sampled sediment, black shale, and zero valent iron was quantitatively evaluated in this research. Effect of coexistence of calcium was also tested, since coexisting ions can enhance the precipitation of phosphate. An empirical kinetic model with fast sorption(k$_t$), slow sorption(k$_s$), and precipitation(k$_p$) was well fitted to experiment data from this research. Langmuir and Freundlich sorption isotherms were also used to evaluated phosphate maximum sorption capacity. Calcium ions at 0, 1 and 5 mM affected the precipitation kinetic coefficient in empirical kinetic model but did not have impact on the maximum sorbed concentration.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.13-23
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• 2000

The distributions of dissolved inorganic nutrient contents were investigated along transection line J (30° N) in the eastern East China Sea in December 1993 and August 1994, respectively. The concentrations of nitrate and silicate in the Kuroshio Surface Water (KSW) with high temperature and high salinity were low below 2μM and 5μM, respectively. However, these were increased sharply with depth and ranged from 20 to 40, 45 to 100μM, respectively, in the Kuroshio Intermediate Water (KIW). The relationship between temperature and nutrients suggests that Kuroshio Intermediate Water with rich nutrients were intruded into the bottom water of the outer continental shelf in the East China Sea. The bottom water of the outer continental shelf was made of two end-members mixing; nutrient depleted warm water and nutrient enriched cold water. Based on temperature, salinity and silicate concentration, the nutrients in the bottom water of the outer continental shelf suggusted to be supplied through the vertical mixing of Kuroshio subsurface water in the depth range of 100～400m. Upwelled nutrient rich water appears to be a important source of nutrients for primary production in the continental shelf area of the East China Sea.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.779-785
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• 1994

The interaction between the cationic dye, thionin(Th) and the anionic surfactant, sodium dodecyl sulfate (SDS) has been investigated by absorption spectra. As the temperature of surfactant solution was increased in premicellar range(S/D=10, 80, and 160) which was much lower than the critical micelle concentration(CMC), the increment or decrement of the molar extinction coeffecient ratio appeared. It was found that the most stable temperature range of the oligomer aggregate in Th-SDS system at S/D=160 was below $60^{\circ}C$. With increasing the concentration of inorganic salt and organic solvents in Th-SDS system, ${\alpha}$-band was increased, but ${\gamma}$=band or J-band was decreased. The orders of ${\alpha}$-band increasing power were $Cl^-$>$ClO{_4}{^-}$>$SO{_4}{^{2-}}$>$NO{_3}{^-}$ and 2-propanol>ethanol>methanol>ethylene glycol.