• Food Science and Biotechnology
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• 제17권1호
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• pp.8-14
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• 2008

The influence of salt concentration on the stability of sodium caseinate (CAS)-stabilized emulsions (20 wt% corn oil, 3.2 wt% CAS, 5 mM imidazole/acetate buffer, pH 7) was examined. In the absence of salt, laser diffraction measurements and optical microscopy measurements indicated there were some large oil droplets ($d>10\;{\mu}m$) in the emulsions stabilized by 0.8 to 3.2 wt% of CAS. The droplet aggregation (mostly droplet coalescence) observed in the emulsions containing ${\leq}2.8\;wt%$ CAS tended to decrease as the CAS concentration increased, however, after which concentration (at 3.2 wt% CAS) depletion flocculation occurred. The addition of $CaCl_2$ (5-20 mM) into the emulsions stabilized by 3.2 wt% CAS prevented the depletion flocculation although there was a small fraction of relatively large individual droplets in the emulsions, which was attributed to electrostatic screening effect and bridging effect of calcium ion. This study has shown that calcium ion that has been reputed to promote droplet aggregation could improve emulsion stability against droplet aggregation in CAS-stabilized emulsions.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.80-84
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• 2017

Re-188 is an excellent and practical radioisotope produced by W-188/Re-188-generator for therapy. We prepared Re-188-tin colloid for therapy of various diseases and tried to treat peritoneal effusion in animal model. Sarcoma-180 cells were injected into ICR mice to induce peritoneal effusion and the mice were grown for 3 d. Re-188-tin colloids (0.25, 0.5, and 1 mCi/mL per 30 g body weight) were injected into the mice and the mice were grown for 90 d. Planar gamma scintigraphy showed even distribution of Re-188-tin colloid radioactivity. Bax expression was found to be dose dependent to Re-188-tin colloid. Normal saline treated group showed the shortest survival time. Among the treated groups, 0.5 mCi dose group showed the longest survival time. In conclusion, Re-188-tin colloid was prepared successfully and showed the feasibility to use as a peritoneal effusion treatment in mice.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 Proceedings of KSEH.Minamata Forum
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• pp.51-53
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• 2005

Disposal of waterwork sludge is important problem in WTP(water treatment plant). Purpose of this study is treated municipal waste water chemically using sludge that is produced in waterwork plant by link to reutilize waterwork sludge. Municipal waste water that use in an experiment used is produced at C university, and is SS 220 mg/L, BOD 145 mg/L, COD 160 mg/L, T-N 52 mg/L and T-P 2.6 mg/L. Used Alum, polymer coagulant and coagulant aid (diatomite, powered activated carbon) as CaO, coagulant as alkaline aid by chemical treatment medicine. In case of does slow speed agitation and stations after pours waterwork sludge in sewage and alkaline aid and coagulant at rapidly mixing the colloidal creation speed is fast and fine colloids concentration was high but settling time is shortened a little and removal rate of pollutant improved by $60{\sim}99%$.

• Bulletin of the Korean Chemical Society
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• 제23권11호
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• pp.1616-1622
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• 2002

If the surfaces of vesicles are chemically modified so that they can be dispersed in organic solvents, the application of vesicular colloids may be expanded. A polymerizable surfactant (BDAC) and nonpolymerizable bipolar surfactant (BPAS) were synthesized in multi-steps. Large vesicles composed of BDAC and BPAS with embedded a cross-linking agent (divinylbenzene) underwent a radical polymerization. BPAS was extracted out using methanol (skeletonization). The headgroup of BDAC was cleaved off via hydrolysis in an acidic condition to yield vesicles where surfaces were covered with -COOH groups. There was no significant change in the overall shape. The skeletonized vesicles appear to have many holes with diameters up to about 25 nm. The holes retained even after hydrolysis. The hydrolyzed vesicles were not dispersed in water and most organic solvents such as tetrahydrofuran and chloroform, but dispersed in methanol.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.243-247
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• 2004

Tile development of a porous iron-oxide coated sand filter system can be modelled with the analytical solution of tile transport equation in order to obtain the operating parameters and investigate the mechanism of arsenic removal. The adsorbed amount from the model simulation showed the limitation of adsorption removal during arsenic transport. A loss reaction term in the transport equation plays a role in the mass loss in column conditions, and then resulted into the better model fitting, particularly, for arsenate. Further, the competitive oxyanions delayed the breakthrough near MCL (10 $\mu$g/L) due to the competitive adsorption. This is the reason why arsenate can be strongly attracted in tile interface of an iron-oxide coated sand, and competing oxyanions can occupy the adsorption sites. Therefore, arsenic retention was regulated by non-equilibrium of arsenic adsorption in a porous iron-oxide coated sand media. The transport-limited process seemed to be affect the arsenic adsorption by coated sand.

• 상하수도학회지
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• 제19권5호
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• pp.605-612
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• 2005

The objective of this study was to evaluate the factors affecting the optimization of coagulation hybrid UF membrane processes for the reuse of secondary effluent from sewage treatment plant. The experimental results obtained from the UF membrane process showed that organic colloids in the size range of $0.2{\mu}m{\sim}1.0{\mu}m$ caused the most substantial influence on the fouling of UF membrane. When using a coagulation pretreatment to UF membrane, alum dosage of 50mg/L resulted in the least reduction in membrane permeate flux. Also, for the rapid mixing process, in-line mixer type was more efficient for organic removal than back mixer type. Therefore, it may be concluded that coagulation-UF hybrid membrane process comparing to UF alone process showed not only higher removal efficiency of organic matter, but also substantial improvement of permeate flux of UF membrane.

• 한국재료학회지
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• 제15권5호
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• pp.285-292
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• 2005

Anti-reflection film was coated by using spherical silica nano colloids. Silica colloid sol was reserved between two inclined slide glasses by capillary force, and particles were convectively stacked to form a film onto the substrate as the water evaporates. As the sliding speed increased, the thickness of the film decreased and the wavelength at the maximum transmittance decreased. The microstructure observed by SEM showed that silica particles were nearly close packed, which enabled the calculation of the effective refractive index of the film. The film thickness was measured by proffer and calculated from the wavelength of maximum transmittance and the effective refractive index. The effective refractive index of the film could be controlled by a subtle controlling of the coating speed and by mixing two different sized silica particles. When the 100 nm and 50 m particles were mixed at 4:1-5:1 volume ratio, the maximum transmittance of $95.2\%$ for one-sided coating was obtained. This is the one that has increased by $3.8\%$ compared to bare glass substrate, and shows that $99.0\%$ of transmittance or $1.0\%$ of reflectance can be achieved by the simple process if both sides of the substrate are coated.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.200-203
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• 2007

Parametric investigation of the polyol process for the preparation of carbon supported Pt nano particles as catalysts for fuel cells was carried out. It was found that the concentration of glycolate anion, which is a function of pH, plays an important role in controlling Pt particle size and loading on carbon. It was observed that Pt loading decreased with increasing alkalinity of the solution. As evidenced by zeta potential measurement, this was mainly due to poor adsorption or repulsive forces between the metal colloids and the supports. In order to modify the conventional polyol process, the effect of the gas purging conditions on the characteristics of Pt/C was examined. By the optimization of the gas environment during the reaction, it was possible to obtain high loading of 39.5wt% with a 2.8 nm size of Pt particle. From the single cell test, it was found that operating in ambient $O_{2}$ at 70oC can deliver high performance of more than 0.6 V at 1.44 A $cm^{-2}$.

• Environmental Engineering Research
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• 제16권3호
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• pp.149-157
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• 2011

Nanofiltration (NF) experiments were conducted to investigate fouling of Al-hydroxide precipitate and the influence of organic compound, inorganic compound, and their combination, i.e., multiple foulants. $CaCl_2$ and $MgSO_4$ were employed as surrogates of inorganic compounds while humic acid was used as surrogate of organic compound. The flux attained from NF experiments was fitted with the mathematical fouling model to evaluate the potential fouling mechanisms. Al-hydroxide fouling with a cake formation mechanism had little effect on the NF membrane fouling regardless of the Al concentration. The NF fouling by Al-hydroxide precipitate was deteriorated in presence of inorganic matter. The effect of Mg was more critical in increasing the fouling than Ca. This is because the Mg ions enhanced the resistances of the cake layer accumulated by the Al-hydroxide precipitate on the membrane surfaces. However, the fouling with Mg was dramatically mitigated by adding humic acid. It is interesting to observe that the removal of the conductivity was enhanced to 61.2% in presence of Mg and humic acid from 30.9% with Al-hydroxide alone. The influence of dissolved matter (i.e., colloids) was more negative than particulate matter on the NF fouling for Al-hydroxide precipitate in presence of inorganic and organic matter.

• Advances in nano research
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• 제9권2호
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• pp.113-122
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• 2020

Surface-Enhanced Raman Scattering (SERS) spectroscopy is a multifaceted surface sensitive methodology which exploits spectroscopy-based analysis for various applications. This technique is based on the massive amplification of Raman signals which were feeble previously in order to use them for appropriate identification at qualitative and quantitative in chemical as well as biological systems. This novel powerful technique can be utilized to identify pathogens such as bacteria and viruses. As far as SERS is concerned, one of the most studied problems has been functionalization of SERS active substrate. Metal colloids and nanostructures or microstructures synthesized using noble metals such as Au, Ag and Cu are considered to be SERS active. Silver and gold are extensively used as SERS active substrates due to chemical inertness and stability in air compare to copper. However, use of Cu as a suitable alternative has been taken into account as it is cheap. Herein, we have synthesized air-stable copper microstructures/nanostructures by chemical, electrochemical and microwave-assisted methods. In this paper, we have also discussed the use of as synthesized copper micro/nanostructures as inexpensive yet effective SERS active substrates for the fast identification of micro-organisms like Staphylococcus aureus and Escherichia coli.