• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.895-898
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• 2009

In this contribution, we designed a general purpose input/output (GPIO) suitable for embedded systems, especially for Bluetooth baseband. Proposed architecture is compatible for the APB bus in AMBA bus architecture. General purpose I/O should be used as multi-functional and versatile interrupt sources. We considered the edge-sensitive mode as well as the level-sensitive mode for acquiring the interrupt sources. Also, we provided an option to select the operation polarity for flexible application to the embedded systems. The designed GPIO module was automatically synthesized, placed, and routed. Implementation was performed through the Altera FPGA and well operated at 25MHz clock frequency.

• Textile Coloration and Finishing
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• v.31 no.3
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• pp.127-134
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• 2019

Cotton fabrics were treated with gelatin to improved their dyeability, color strength toward cochineal dye. Gelatin were used as the protein. Gelatin is containing a large number of hydrophilic groups. Pad-dry-cure method was used for the treatment process(10g/L concentration). The scanning electron micrograph showed the gelatin was deposited on the surface of cotton. Pretreated fabrics were mordanted with 10%(owf) alum. Then the fabrics were dyed with cochineal. Compared with original cotton fabric the K/S value with cochineal dyes was significantly improved on gelatin modified cotton. Treating cotton with 10g/L concentration gelatin offered higher cochineal adsorption. The dyeability of pH 4 yielded the highest color strength. In dyebaths of a ratio of ethanol and water such as; 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10, fabrics were dyed. The ratio of ethanol and water had powerful effects on solution polarity. Cochineal dye uptake showed maximum value, when the proportion of ethanol and water was 9:1. Dyeing at increased temperatures and with increased time resulted in higher dye uptake and reddish-purple color(5RP). The washing fastness was 1-2grade, and the fastness to light was 2-3grade.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.423-432
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• 2022

Magnetic biochar produced from pyrolysis of dairy cattle manure was used to develop an effective sorbent for arsenic purification from aqueous solution. Biomass and magnetized biomass were pyrolyzed in a tube furnace with 10 ℃/min heating rate at 450 ℃ under nitrogen flow of 100 cm³/min for 2 h. Biochars were characterized by SEM-EDX, BET, XDR, FTIR, TGA, zeta potential analysis. The resultant biochar and magnetic biochar were opposed to 50-100-500 ppm As(V) laden aqueous solution. Adsorption experiments were performed by using ASTM 4646-03 batch method. The effects of concentration, pH, temperature and stirring rate on adsorption were evaluated. As(V) was successfully removed from aqueous solution by magnetic biochar due to its highly porous structure, high aromaticity and polarity. The results suggest dairy cattle manure pyrolysis is a promising route for managing animal manure and producing a cost effective biosorbent for efficient immobilization of arsenic in aqueous solutions.

• The Journal of Engineering Geology
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• v.19 no.4
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• pp.509-515
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• 2009

Three earthquakes with local magnitude ($M_L$) greater than 3.0 occurred on April 24, June 2 and September 12 in 1999 nearby the Gyeongju area. Redetermined epicenters were located within the radius of 1 km. We carried out waveform inversion analysis to estimate focal mechanism of June 2 event, and P and S wave polarity and their amplitude ratio analysis to estimate focal mechanisms of April 24 and September 12 events. June 2 and September 12 events had similar fault plane solutions each other. The fault plane solution of April 24 event included those of other 2 events, but its distribution range was relatively broad. Focal mechanisms of those events had a strike slip faulting with a small normal component. P-axes of those events were ENE-WSW which were similar to previous studies on the P-axis of the Korean Peninsula. Considering distances between epicenters, similarities of seismic waves and sameness of polarities of seismic data recorded at common seismic stations, these events might occurred at the same fault. The seismic moment of June 2 event was estimated to be $3.9\;{\times}\;10^{14}\;N{\cdot}m$ and this value corresponded to the moment magnitude ($M_W$) 3.7. The moment magnitude estimated by spectral analysis was 3.8, which was similar to that estimated by waveform inversion analysis. The average stress drop was estimated to be 7.5 MPa. Moment magnitudes of April 24 and September 12 events were estimated to be 3.2 and 3.4 by comparing the spectrum of those events recorded at common single seismic station.

• KSBB Journal
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• v.21 no.2
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• pp.151-156
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• 2006

Vitamin-C is one of the typical bioactive substances widely used in the cosmetic and pharmaceutical applications. It is well known that the bioavailability of vitamin-C decreases with time because it is spontaneously oxidized in the presence of oxygen. In this study, vitamin-C inclusion complexes were prepared by formulating vitamin-C with 2-hydroxypropyl-${\beta}$-cyclodextrin (HP-${\beta}$-CD) to protect vitamin-C from being oxidized. Vitamin-C inclusion complexes were prepared by a solvent evaporation method using a rotary evaporator and various solvents of different dielectric constant such as ethanol, methanol and distilled deionized water to investigate the effect of solvent polarity on the stability of vitamin-C. To estimate the stability of inclusion complexes, samples were stored in a 50 mM phosphate buffer solution of pH 7.0 for 24 hours at $25{\pm}0.1^{\circ}C$ and the degradation rate of vitamin-C was calculated using a high performance liquid chromatography. The stability of vitamin-C was observed to improve with the increase of solvent polarity.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.562-569
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• 1994

The retention data of twenty one monosubstituted phenols in the eluent systems containing 30∼70% of methanol or acetonitrile as organic modifiers, on $ C_{18}$ and Phenyl columns were collected to investigate the effect of the substituted groups on the retention of phenols. The capacity factors of the solutes except amino phenols are greater on $ C_{18}$ than on Phenyl column. And all the solutes have shown greater capacity factors in methanol-water than that in acetonitrile-water as a mobile phase. Generally the elution order between meta and para isomers of monosubstituted phenols in consistent (p < m) regardless of the polarity of the substituted group. But the elution order between ortho and meta isomers of phenol varies with regard to the polarity of the substituted group. The retention of the monosubstituted phenols has been influenced by the interaction between the solute and unreacted silanol of columns as well as the interaction between the solute and $ C_{18}$ or phenyl group of columns. And then, the effect of unreacted silanol on the retention of the monosubstituted phenols is greater on $ C_{18}$ than on Phenyl column. And the greater hydrogen bonding acceptor basicity(${\beta}$) of the substituted group is, the greater this effect is. The relationship between the retention of the monosubstituted phenols and their parameters such as van der Waals volume(VWV) and hydrogen bonding acceptor basicity(${\beta}$) has been investigated. The good linearity has been observed in the plot log k' vs. (1.01VWV/100-1.84${\beta}$). In consequence, the retention of the monosubstituted phenols on $ C_{18}$ and Phenyl columns can be easily predicted by the parameter (1.01VWV/100-1.84${\beta}$).

• Clean Technology
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• v.20 no.3
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• pp.226-231
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• 2014

This study presents a micromolding for the synthesis of Janus particles with reconfigurable shape by pH stimuli. First, we use acrylic acid (AA) as pH responsive monomer in the hydrophilic part and trimethylolpropane triacylate (TMPTA) in the hydrophobic part, respectively. The change of acidity in solvent induces the swelling of hydrophilic part in the Janus particles. The pH-responsive Janus particles show different swelling ratio of hydrophilic part in according to composition of acrylic acid in diverse range (0-70% v/v) and pH (3-11). As the concentration of acrylic acid in the hydrophilic part and environmental pH increase, the hydrophilic part in the Janus particles is proportionally swelled. Second, we fabricate novel type of Janus particles with two different hydrophilicities. As a proof of concept, we have applied acrylic acid (AA) and 2-(dimethylamino)ethyl methacrylate (DAEMA) into each part because the monomers provide reverse responsive activity. As expected, these Janus particles show different shape anisotropies with reconfigurable property in accordance with the polarity of each part at same acidity of environmental solvent. We envision that the stimuli responsive Janus particles have a wide application from fundamental science to diagnostic apparatus.

• Journal of Pharmaceutical Investigation
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• v.38 no.1
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• pp.31-38
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• 2008

The objective of this work is to study transdermal delivery of levodopa using iontophoresis and evaluate various factors which affect the transdermal transport. Levodopa is unstable in aqueous solution, and, in order to establish a stable condition for levodopa for the duration of experiment, we investigated the stability of levodopa in aqueous solutions of different pHs with/without the addition of dextrose or the application of current. Using stable aqueous solution, we have studied the effect of pH, polarity and penetration enhancer (ethanol) on transdermal flux and compared the results. We also investigated the iontophoretic flux from hydroxypropyl cellulose (HPC) hydrogel. In vitro flux study was performed at $33^{\circ}C$, using side-by-side diffusion cell. Full thickness hairless mouse skin and rat skin were used for this work. Current densities applied were 0.4 or $0.6mA/cm^2$ and current was off after 6 hour application. Stability study showed that levodopa solution with a pH 2.5 or 4.5 maintained the initial concentration of levodopa for 24 hours with the addition of 5% dextrose. However, at pH 9.5, levodopa was unstable and 30 to 40% of levodopa degraded within 24 hours, even with the addition of 5% dextrose. Hydrogel swollen with dextrose added levodopa solution maintained about 97% of the initial concentration of levodopa for 13 days, when stored in $4^{\circ}C$. The application of current did not affect the stability of levodopa in hydrogel. Flux study from levodopa solution with pH 2.5 showed that cathodal delivery of levodopa was higher than passive or anodal delivery. When the pH of the donor solution was 4.5, anodal delivery of levodopa was higher than passive or cathodal delivery. These results seem to indicate that electroosmosis plays more dominant role than electrorepulsion in the flux of levodopa at pH 2.5, and the reverse situation applies for pH 4.5. The passive flux was unexpectedly high for the ionized levodopa. Similar to the results from aqueous solution, cumulative amount of levodopa transported trom HPC hydrogel by cathodal delivery was significantly higher than passive or anodal delivery. The treatment of 70% ethanol cotton ball by scrubbing increased passive, anodal and cathodal flux, with the largest increase for anodal flux. These results indicate that iontophoretic delivery of zwitterion such as levodopa is much complicated than that can be expected from small ionic molecules with single charge. The results also indicate that the balance between electroosmosis and electrorepulsion plays a very important role in the transport through skin.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.605-610
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• 2010

The devices based on electrically erasable programmable read-only memory (EEPROM) structure are proposed for the detection of external electric charges. A large size charge contact window (CCW) extended from the floating gate is employed to immobilize external charges, and a control gate with stacked metal-insulator-metal (MIM) capacitor is adapted for a standard single polysilicon CMOS process. When positive voltage is applied to the capacitor of CCW of an n-channel EEPROM, the drain current increases due to the negative shift of its threshold voltage. Also when a pre-charged external capacitor is directly connected to the floating gate metal of CCW, the positive charges of the external capacitor make the drain current increase for n-channel, whereas the negative charges cause it to decrease. For an p-channel, however, the opposite behaviors are observed by the external voltage and charges. With the attachment of external charges to the CCW of EEPROM inverter, the characteristic inverter voltage behavior shifts from the reference curve dependent on external charge polarity. Therefore, we have demonstrated that the EEPROM inverter is capable of detecting external immobilized charges on the floating gate. and these devices are applicable to sensing the pH's or biomolecular reactions.

• Polymer(Korea)
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• v.36 no.6
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• pp.699-704
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• 2012

Double-layered polymeric carrier was designed for release control of hydrophilic drug in oral administration. Biopolymeric chitosan and alginate were examined as polar absorbents, poly(D,L-lactide) as a hydrophobic shell, and theophylline and diclofenac sodium as loading drugs. The fabrication of the carriers was prepared in the form of double-layered microsphere for delayed and successively extended release, which consisted of outer shell of poly(D,L-lactide) and inner core of alginate or chitosan with drugs. Morphologies and drug-release behaviors of the carriers were investigated, which were influenced by a combination of polarity between carrier and drug. It was confirmed that the relative polarities of the carriers, the drugs, and the environmental pH affected significantly the drug-release property.