• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.178-178
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• 2016

Every display is equipped with a cover glass to protect the underneath displaying devices from mechanical and environmental impact during its use. The strengthened glass such as Gorilla glass.$^{TM}$ has been exclusively adopted as a cover glass in many displays. Conventionally, the strengthened glass has been manufactured via ion-exchange process in wet salt bath at high temperature of around $500^{\circ}C$ for hours of treatment time. During ion-exchange process, Na ions with smaller diameter are substituted with larger-diameter K ions, resulting in high compressive stress in near-surface region and making the treated glass very resistant to scratch or impact during its use. In this study, PIIID (plasma immersion ion implantation and deposition) technique was used to implant metal ions into the glass surface for strengthening. In addition, due to the plasmonic effect of the implanted metal ions, the metal-ion implanted glass samples got colored. To implant metal ions, plasma immersion ion implantation technique combined with HiPIMS method was adopted. The HiPIMS pulse voltage of up to 1.4 kV was applied to the 3" magnetron sputtering targets (Cu, Ag, Au, Al). At the same time, the sample stage with glass samples was synchronously pulse-biased via -50 kV high voltage pulse modulator. The frequency and pulse width of 100 Hz and 15 usec, respectively, were used during metal ion implantation. In addition, nitrogen ions were implanted to study the strengthening effect of gas ion implantation. The mechanical and optical properties of implanted glass samples were investigated using micro-hardness tester and UV-Vis spectrometer. The implanted ion distribution and the chemical states along depth was studied with XPS (X-ray photo-electron spectroscopy). A cross-sectional TEM study was also conducted to investigate the nature of implanted metal ions. The ion-implanted glass samples showed increased hardness of ~1.5 times at short implantation times. However, with increasing the implantation time, the surface hardness was decreased due to the accumulation of implantation damage.

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.379-387
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• 1996

The objects of the present study were to establish the method of purification, subunit dissociation of verotoxin-2 (VT2) produced by Escherichia coli O157:H7, and to investigate the characteristics of purified verotoxin-2 such as molecular weight and composition of amino acid. The results were summerized as follows; Verotoxin-2 was extracted by addition of polymyxin B sulfate into bacterial cell lysate prepared from Escherichia coli O157:H7(KSC109). As an initial step, the bacterial cell lysate was precipitated with 30% saturated ammonium sulfate. The precipitated crude toxin was then subjected to anion-exchange, chromatofocusing and cation-exchange chromatography. Using this scheme, we obtained highly purified toxin with a specific activity of $1.1{\times}10^9$ $CD_{50}/mg$. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) for purified VT2 showed two protein bands. The upper band, approximately 32 Kd, was supposed as A subunit and the lower band, approximately 7.7 Kd, was supposed as B subunit. When the toxin was separated in the subunit-dissociating solution, two peaks emerged with retention times of 15 and 28 min by HPLC. These peaks represented A subunit and B subunit, respectively. The amino acid composition of purified VT2 were made up in order of glutamic acid, histamine, asparaginic acid, histidine, lysine, alanine and leucine etc. The largest amount among the amino acid composing VT2 was methionine.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.517-524
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• 2010

In this study, the 1D apparent shear stress model for vegetated compound open-channel flows was suggested. To consider the effect of momentum exchange between main channel and floodplain, the eddy viscosity concept was used in the present model. The interfacial eddy viscosity in the interface of main channel and floodplain was determined from the 3D Reynolds stress model. The evaluated interfacial eddy viscosity appears to be good agreement with those proposed previously. To investigate the effect of interfacial eddy viscosity, sensitive analysis was carried out. the computed backwater profiles are nearly identical with respect to the value of the interfacial eddy viscosity. However, the discharge conveyed by the floodplain changes is proportional to the interfacial eddy viscosity. Finally, the changes of the interfacial eddy viscosity due to the vegetation density and vegetation height were examined. The computed results of interfacial eddy viscosity are in proportion to the vegetation density and vegetation height, and the interfacial eddy viscosity has a range of $(2-5)\;{\times}\;10^{-4}$.

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.38-45
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• 2007

To characterize thermo-chemical feature of sugar conversion of woody biomass, poplar wood ($Populus\;alba{\times}glandulosa$) powder was treated with supercritical water system. Supercritical water treatment (SCWT) was performed for 60 seconds at different temperatures (subcritical zone 350; supercritical zone $300,\;400,\;425^{\circ}C$) under two pressures $230{\pm}10atm$ as well as $330{\pm}10atm$, respectively, using flow type system. After separation of solid residues from SCWT products, the monomeric sugars in aqueous part converted from poplar wood powder were quantitatively determined by high performance anionic exchange chromatography [HPAEC] equipped with PAD detector and Carbo Pac PA10 column. As the temperature treated increased, the degradation of poplar wood powder was enhanced and ca 83% of woody biomass was dissolved into the water at $425^{\circ}C$. However, the pressure didn't help the degradation of biomass components. At subcritical temperature range, xylose was first formed by degradation of xylan, which is main hemicellulose component in hardwood species, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical temperature. In the supercritical water system the maximum yield of monomeric sugars amounts to ca. 7.3% based on oven dried wood weight at $425^{\circ}C$.

• Journal of Yeungnam Medical Science
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• v.3 no.1
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• pp.103-110
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• 1986

Cytochrome P-450(CP-450) is one of the three components of the liver microsomal enzyme system which hydroxylates fatty acids, hydrocarbons and a variety of drugs and other foreign compounds. Female Balb/c mice were immunized with purified polychlorinated bipheny(PCB)-induced CP-450 LMII. The spleen cells derived from immunized mice were fused with $SP^2$ myeloma cells using polyethylene glycol(PEG 3500). The hybrid cells were selected by hypoxanthine-aminopterine and thymidine(HAT) medium and the culture fluid were screened by enzyme-linked immunosorbent assay to CP450 LMII. The hybrid cess(${\times}10^7$) were innoculated into intraperitoneal cavity of Balb/c mice for the purpose of production of ascitic fluids. Monoclonal antibody(Mab) was purified from ascitic fluid by DEAE cellulose ion exchange chromatography and $I^{125}$-labeled Mab was also confirmed by autoradiography and SDS-polyacrylamide gel electrophoresis (MW : 55,000 and 110,000).

• Quality Improvement in Health Care
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• v.14 no.1
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• pp.55-59
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• 2008

Background : The purpose of inner cannula is to protect the upper air way and permit air to pass freely, in addition, to provide endotracheal suction, artificial respiration and to maintain adequate oxygen saturation. The tube needs to be sterilized for maintenance and cleanness of air way and for prevention of bronchospasm. However, it has been reported that there is no guideline for sterilization and many hospitals conduct their own sterilization methods, for example, once a day(13's general hospital), three times a day(The Catholic University of Korea ST Mary's hospital) or even no cleansing. Consequently, the QI team of our hospital suggested the SOP(standard operating procedure) of sterilization and evaluate cost and time effect in nursing. Method : 1) Benchmarking of 13's neurosurgery department of general hospital in Seoul 2) Investigation of test records of sputum culture from patients with intubation for tracheotomy 3) Check of results of O2 Sat. monitoring to confirm of maintaining opened air way Result : 1) Improvement of process: decrease of excess sterilization of inner cannula (from 3 times a day to once a day) 2) Cost effects: saving over 10 million won per one year 3) Providing better nursing: time effects (30 min a day) permit to conduct more nursing activities Conclusion : It can get Cost and time effects in nursing with improved sterilization method of inner cannula. It needs to do research on improvement of the monthly exchange protocol of outer cannula and provide supporting data for the proper exchange schedule. The result of additional microorganism detection from patients with new process needs to be evaluated further more.

• Journal of the Korean Magnetics Society
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• v.13 no.2
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• pp.59-63
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• 2003

Superparamagnetic properties of self-aggregated cobalt nanoparticles in the perfluorinated ion-exchange polymeric membrane (MF-4SK) prepared by ion-exchange and recovery methods were investigated by transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) magnetometer at various temperatures. Our experimental results show that cobalt nanoparticles in MF-4SK for the concentration of $7.8{\times}10^{19}$ atoms per 1 g of polymer membrane exhibit superparamagnetic properties above the average blocking temperature ($T_{B}$), which is determined to be around 185 K at applied field of 500 Oe. The average particle radius of 4.0 nm achieved from Langevin function fit is in good agreement with TEM observations. This experimental evidence suggests that cobalt nanoparticles in polymer film obey a single domain theory. The results are discussed in the light of current theory for the superparamagnetic behavior of magnetic nanoparticles.

• KSBB Journal
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• v.16 no.6
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• pp.533-537
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• 2001

${\alpha}$-lactalbumin and ${\beta}$-lactoglobulin in whey proteins were separated by high performance membrane chromatography (HPMC). The separation mechanism involved anion-exchange, and the stationary phase was anion CIM (Convective Interaction Media) DEAE, QA disk and cation exchanger SO$_3$(16${\times}$3 mm). Two types of mobile phase were used, buffer A (20 mM Tris-HCI, pH 7.3) and buffer B(buffer A + 1 M NaCl), As the amount of NaCl dissolved in buffer linearly increased, which enabled a gradient elution mode. The optimum mobile phase and operating condition (Buffer A/Buffer B = 100/0 - 30/70 vol%, gradient time 1 min, 30/70 - 10/90 vol.%, gradient time 2 min) were experimentally determined. In this experimental condition, ${\alpha}$-lacta1bumin, ${\beta}$-lactoglobulin were separated within 5 min at a mobile phase flow rate of 4 mL/min.

• KSBB Journal
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• v.14 no.3
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• pp.384-388
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• 1999

We have used high pH anion-exchange chromatography to analyze low level (below $20{\mu}M$) $\alpha$-D-glucose-1-phosphate (G-1-P) that can be used as a cytostatic compound, an antibiotic, and immunosuppressive drug. Our chromatographic method afforded excellent peak resolution and seletivity for glucose-6-phosphate and various maltooligosaccharides as well as G-1-P. The pulsed amperometric detector yielded linear response on G-1-P ranging from 2 - $20{\mu}M$, giving slope of $4.8{\times}10^4$(peak area/${\mu}M$). The detection limit was $2{\mu}M$. This method was applied to the purification of thermophilic $\alpha$-glucan phosphorylase from Thermus caldophilus. The technique will be extremely useful in future studies concerning carbohydrate metabolism in living organisms.