• Archives of Pharmacal Research
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• v.20 no.3
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• pp.269-274
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• 1997

Solubilities of oleanolic acid and ursolic acid in aqueous surfactant solutions, liquid polyethylene glycols (PEG), and solvents of various polarity were measured. The results showed that the solutes were slightly or moderately solubilized in the surfactant solutions and the liquid PEGS. It was also revealed that the solutes were slightly soluble in the solvent of either extreme polarity or nonpolarity, but moderately soluble in solvents of intermediate polarity of which solubility parameters are around 10. The solubility parameters of these solutes were calculated from the group contribution to be 10.2 for both of them. Of the solvents tested, tetramethylurea was exceptionally effective in solubilizing the solutes. The solutes were also moderately soluble in the aqueous cosolvents containing tetramethylurea. This suggests that the mixed systems of tetramethylurea could be employed for the solubilization in the formulation of these compounds as an aqueous system.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06b
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• pp.129-153
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• 1996

In aqueous slurry processing of silicon nitride, the interaction of dispersant and binder on the surface of particles was studied to identify the effect of these additives on ceramic powder processing. Polymethacrylic acid (PMAA) and polyvinyl alcohol (PVA) were used as dispersant and binder, respectively. the adsorption isotherms of PMAA and PVA for the silicon nitride suspension were determined, while the adsorption of PMAA was differentiated in the mixed additive system by ultraviolet spectroscopy. These experiments were done in order to investigate the effect of these organic additives on the physicochemical properties of silicon nitride suspensions. The electrokinetic behavior of silicon nitride was subsequently measured by electrokinetic sonic amplitude (ESA). As PMAA adsorbed onto silicon nitride, the isoelectric point (pHicp) shifted from pH=6.7 to acidic pH, depending on the surface coverage of PMAA. However, adsorption of PVA did not change the pHicp of suspensions, but did decrease the surface potential of silicon nitride moderately. The rheological behavior of silicon nitride suspensions was measured to assess the stability of particles in aqueous media, and was correlated with the electrokinetic behavior and adsorption isotherm data for silicon nitride.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.15-24
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• 1989

The transport of Chromium(Vl) ion from waste water throughl the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid parafnn oil were analyzed. Extraction euperiments were carried out to observe the effect of system variables, such as stirring speed, concentration of carrier, and NaOH in internal aqueous phase, and concentrations of H$_2$SO$_4$and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt. ％ and liquid parafnn oil concentration is 50 vol. ％. The transport of chromium(VI) ion in bacth extractor increased with increasing carrier concentration, the volume ratio of emulsion to external aqueous phases, and initial concentration of chromium(VI) ion under the optimum stirring speed of chromium(VI) ion below 2 ppm. The theoretical equation on the transport of chromium(Vl) ion agreed well with the experimental results.

• Bulletin of the Korean Chemical Society
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• v.19 no.6
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• pp.650-654
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• 1998

Aggregations of 1,1'-diethyl-2,2'-carbocyanine iodide (DCI) and 1,1'-diethyl-2,2'-dicarbocyanine iodide (DDT) in aqueous solution have been investigated by the steady-state absorption spectroscopy. The equilibrium constants for dimerization of DCI and DDT are found to be $(9.8{\pm}0.5){\times}10^4 \;and\; (1.6{\pm}0.5){\times}10^5\; M^{-1}$, respectively, at 293 K. The enthalpy changes for the dimerization of DCI and DDT are -6.7±0.7 and -7.7±0.8 kcal/mol, respectively. The results show that the dispersion force plays an important role in the aggregation of DCI and DDT in aqueous solution. The absorption bandwidth of DCI/ethanol system has been measured as a function of temperature, providing the evidence for no strong interaction between DCI and solvent molecules. The participation of hydrophobic force in driving the aggregation is suggested. For the first time, DCI in aqueous solution is found to form a new aggregate which has both J- and H- bands.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.109-122
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• 2018

This work highlights extraction and removal of Lignosulfonate using sunflower oil-Tri-n-octylamine (TOA) system in bulk liquid membrane transport. Maximum extraction and recovery percentages of 92.4% and 75.2% were achieved. Optimum manifold operating conditions were: 4 vol.% TOA, $2{\pm}0.1$ feed phase pH, 300 rpm stirring speed, at $40^{\circ}C$ with 0.2 (M) $Na_2SO_4$ solution. 1:2 (organic/aqueous) and 1:1 (aqueous/aqueous) phase ratios produced best results. Extraction (36.85 kJ/mol) was found to be intermediate controlled and stripping (54.79 kJ/mol) was chemical reaction controlled. Kinetic estimation of data with higher rate constants for stripping vis-${\grave{a}}$-vis extraction showed latter to be rate determining.

• Journal of Environmental Science International
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• v.11 no.1
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• pp.85-91
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• 2002

The effects of initial concentration of dissolved oxygen content, Cu(II) and EDTA in an aqueous Cu(II)-EDTA solution on $TiO_2$ photo-oxidation of EDTA were investigated using $TiO_2$ (Degussa P-25) and UV irradiation at $20{\circ}C$. In the presence of dissolved oxygen and/or Cu(II) the photo-oxidation rates of EDTA were enhanced. The rates linearly increased in the range of initial Cu(II) concentration below 1.79 mM, while abode this concentration those were kept constant. The trend or the EDTA photo-oxidation rates appeared to be akin to the Langmuir-Hinshelwood equation farm and the k values calculated were 0.05 mM/min for the free-EDTA system, and 0.17 mM/min far the Cu(II)-EDTA system. These meant the aqueous EDTA decomposition was enhanced due to weakening of the intra-molecular bond strength of EDTA by complexation with Cu(II) added. It was concluded the decomposition of aqueous EDTA by $TiO_2$ photo-oxidation was maximum in the presence of dissolved oxygen supplied by air purging and of Cu(II) with its concentration for 1:1 Cu(II)-EDTA complexation ratio.

• BMB Reports
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• v.47 no.5
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• pp.292-297
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• 2014

Age-related macular degeneration (AMD) is the leading cause of blindness in the world. Evidence indicates that the suppression of the ubiquitin-proteasome system (UPS) contributes to the accumulation of toxic proteins and inflammation in retinal pigment epithelium (RPE), the functional abnormalities and/or the degeneration of which are believed to be the initiators and major pathologies of AMD. To identify new protein associations with the altered UPS in AMD, we used LC-ESI-MS/MS to perform a proteomic analysis of the aqueous humor (AH) of AMD patients and matched control subjects. Six UPS-related proteins were present in the AH of the patients and control subjects. Four of the proteins, including 26S proteasome non-ATPase regulatory subunit 1 (Rpn2), were increased in patients, according to semi-quantitative proteomic profiling. An LC-MRM assay revealed a significant increase of Rpn2 in 15 AMD patients compared to the control subjects, suggesting that this protein could be a biomarker for AMD.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.96-104
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• 1998

It was possible to produce W/O/W one step multiple emulsion on the system which satisfied following conditions. 1. 1-5％ of hydrophilic liquid surfactant over HLB20 and lipophilic liquid surfactant which has HLB 3∼5 2. Non wax copolymers as oil thickener 3. More than 0.5％ of carbomer as aqueous thickener 4. The manufacturing process which neutralize the dispersed carbomer (2.0％ in water), after emulsifying. For the selective addition into inner and outer aqueous phase, we melted the glucose in water before emulsifying. Using an Anthrone analysis method, we analyzed the encapsulation yield of glucose in inner water phase. It was possible to raise the water encapsulation yield of the multiple emulsion through the following conditions. 1. Using of anionic hydrophilic surfactant(HLB 40) and lipophilic surfactant (HLB 3∼5) 2. Controlling the ratio of hydrophilic surfactant and lipophilic surfactant 3. Strengthening interface with increase of non wax oil thickener. When the separated adding process of glucose was adopted, approximately 85％ of glucose was added selectively within inner aqueous phase.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.79-84
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• 2004

The existing technological schemes for processing rhenium-containing raw materials involve the recovery of Re from solutions, which can be effectively achieved by anion exchange method. The application of anion exchange also allows to study rhenium state in aqueous solutions and to develop analytical control methods. The present work is focused on investigation of ion exchange equilibrium in the analytical system Re(VII)-HCl-$SnCl_2$-KSCN-anion exchanger by means of sorption-desorption method as well as by electron, IR- and diffuse reflection spectroscopy. It was shown that rhenium can be quantitatively recovered from this system. It is proposed to use the sorption-spectroscopic method for Re(VII) determination in aqueous solutions. The calibration curve is linear in the concentration range of 0.5-20.0 mg/L (sample volume is 25.0 mL) and the detection limit is 0.05 mg/L. The presence of Mo(VI), Cu(II), Fe(II, III), Ni(II), Zn(II) as well as $K^+,\;Na^+$ do not hinder the solid-phase determination of rhenium. Rhenium (VII) determination by diffuse reflection spectroscopy was carried out in model solutions as well as in samples of river-derived water and in solutions obtained after the dissolution of spent catalysts.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.78-84
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• 2014

Viscosity agents were added to water to improve extinguishing performance of low pressure water mist suppression system on wood cribs fire, and a small scale wood cribs fire experiment was conducted to measure the extinguishing performance. CMC and agar were used for viscosity agent and as the amount of viscosity agent enlarges, it showed the increase of the viscosity of aqueous solution and the decrease of the fluidity. On wood cribs fire experiment, the extinguishing efficiency was improved with supplemental viscosity agent as it enhanced the adhesive time of aqueous solution on the wood, and therefore expanded the contact time of fire surface. The surface tension of aqueous solution was decreased with the addition of agar which to be assumed as an increase factor of extinguishing efficiency. By the extinguishing experimental result, the most effective extinguishing agent was CMC 0.6 wt.%, with the flame suppression time and the extinguishing time were reduced by 70s and 93s respectively at this concentration.