• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.541-549
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• 2020

The Drug Delivery System (DDS) is defined as a technology for designing existing or new drug formulations and optimizing drug treatment. DDS is designed to efficiently deliver drugs for the care of diseases, minimize the side effects of drug, and maximize drug efficacy. In this study, the optimization of tripolyphosphate (TPP) concentration on the size of Chitosan nanoparticles (CNPs) produced by crosslinking with chitosan was measured. In addition, the characteristics of Fe₃O₄-CNPs according to the amount of iron oxide (Fe₃O₄) were measured, and it was confirmed that the higher the amount of Fe₃O₄, the better the characteristics as a magnetic drug carrier were displayed. Through the ninhydrin reaction, a calibration curve was obtained according to the concentration of γ-aminobutyric acid (GABA) of Y = 0.00373exp(179.729X)-0.0114 (R² = 0.989) in the low concentration (0.004 to 0.02 wt%) and Y = 21.680X-0.290 (R² = 0.999) in the high concentration (0.02 to 0.1 wt%). Absorption was constant at about 62.5% above 0.04 g of initial GABA. In addition, the amount of GABA released from GABA-Fe₃O₄-CNPs over time was measured to confirm that drug release was terminated after about 24 hr. Finally, GABA-Fe₃O₄-CNPs performed under the optimal conditions were spherical particles of about 150 nm, and it was confirmed that the properties of the particles appear well, indicating that GABA-Fe₃O₄-CNPs were suitable as drug carriers.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.87-96
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• 2014

The objectives of this study were to characterize the physicochemical properties and mineralogy of Hwangto (yellow residual soils) from the southwestern part of Korea and to understand the soil-forming processes of the residual soils from their parent rocks. Both the yellowish residual soils as well as the unweathered and weathered parent rocks were obtained from Jangdong-ri, Donggang-myun, Naju, Jeollanam-do, Korea. The soil samples were examined to analyze the said soil's physicochemical properties such as color, pH, and particle size distribution. A scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were performed in order to understand the mineralogy, chemical composition, and morphology of the soils. Two thin sections of a parent rock were analyzed to study its mineral composition. A particle size analysis of the soils indicates that the residual soil consists of mainly silt and clay (approximately 95%) and that soil textures are silty clay or silt clay loam. The soil colors of the residual soil are dark brown (7.5YR 3/4) through yellowish red (5YR 4/6). The pH of the residual soil ranges from 4.3 to 5.1. The major minerals of the parent rocks were quartz, biotite, chlorite, and plagioclase. The mineralogy of the sand fraction of the residual soil was quartz, biotite, muscovite and sanidine. The mineralogy of the silt fraction of the residual soil was quartz, biotite, muscovite, Na-feldspar, K-feldspar, and sanidine. The clay mineralogy of the soil was goethite, kaolinite, ilite, hydroxy-interlayed vermiculite(HIV), vermiculite, mica, K-feldspar and quartz. The mineral composition of the residual soil and the parent rock indicates that feldspar and mica in the parent rock weathered into illite, vermiculite and hydroxy-interlayed vermiculite(HIV), and finally changed into kaolinite and halloysite in the yellowish residual soils.

• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.155-162
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• 1997

Zinc oxide(ZnO) thin films were deposited on r-plane sapphires from a solution containing zinc acetate. The films were obtained in a hot wall reactor by the pyrolysis of an aerosol produced by an ultrasonic generator. The crystallinity, surface morphology and composition of the films have been studied using the x-ray diffraction method(XRD) scanning electron microscopy(SEM) and Auger electron spectroscopy (AES) respectively. The influences of the substrate temperature on the crystallinity of the films were studied. Strongly (110) oriented ZnO films were obtained at a substrate temperature of $350^{\circ}C$. The resistivity was increased to above $3{\times}10^{6}{\Omega}{\cdot}cm$ with copper doping and vapor oxidation.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.185-195
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• 2012

Due to the high reduction and sorption capacity as well as the large specific surface area, nanosized mackinawite (FeS) is useful in reductively transforming chlorinated organic pollutants and sequestering toxic metals and metalloids. Due to the dynamic nature in its colloid stability, however, nanosized FeS may be washed out with the groundwater flow or result in aquifer clogging via particle aggregation. Thus, these nanoparticles should be modified such as to be built into permeable reactive barriers. This study employed coating methods in efforts to facilitate the installation of permeable reactive barriers of nanosized mackinawite. In applying the methods, nanosized mackinawite was coated on non-treated silica sand (NTS) and chemically treated silica sand (CTS). For both silica sands, the maximum coating of mackinawite occurred around pH 5.4, the condition of which was governed by (1) the solubility of mackinawite and (2) the surface charge of both silica and mackinawite. Under this pH condition, the maximum coating by NTS and CTS were found to be 0.101 mmol FeS/g and 0.043 mmol FeS/g respectively, with such elevated coatings by NTS likely linked with impurities (e.g., iron oxides) on its surface. Arsenite sorption experiments were performed under anoxic conditions using uncoated silica sands and those coated with mackinawite at the optimal pH to compare their reactivity. At pH 7, the relative sorption efficiency between uncoated NTS and coated NTS changed with the initial concentration of arsenite. At the lower initial concentration, uncoated NTS showed the higher sorption efficiency, whereas at the higher concentration, coated NTS exhibited the higher sorption efficiency. This could be attributed to different sorption mechanisms as a function of arsenite concentration: the surface complexation of arsenite with the iron oxide impurity on silica sand at the low concentration and the precipitation as arsenic sulfides by reaction with mackinawite coating at the high concentration. Compared to coated NTS, coated CTS showed the lower arsenite removal at pH 7 due to its relatively lower mackinawite coating. Taken together, our results indicate that NTS is a more effective material than CTS for the coating of nanosized mackinawite.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.562-568
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• 2001

Devitrifiable solder glass/$ZrB_2$ sintered composites were prepared by using glass with the composition of $60ZnO-20B_2O_3-10SiO_2-10PbO$(in wt%) and $ZrB_2$, powder as starting materials under the $N_2$atmosphere. $ZrB_2$which the good conduction materials showed sensitive oxidation characteristics, because some parts of the $ZrB_2$in specimens changed into the insulated phase of $ZrO_2$. These Phenomena would be estimated that it caused a few amount of residual oxygen in the furnace and/or specimens and the coordination number change of $B_2O_3$ in the glass. The sintering temperature and the mixed ratios of each phase were control of large ranged the resistivity ranged from 10 to 10$^{3}{\Omega}/cm^2$ orders, and to make a conductible microstructure. From these results, it would be explained that the conduction path of $ZrB_2$particles built up within sintered glass matrix.

• Conservation Science in Museum
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• v.17
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• pp.69-84
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• 2016

Yuso is the term for decorative tassels of a braided string which hangs a scroll painting. This study, drawing on extant research concerning the yuso made for Joseon period portrait scrolls of kings and meritorious retainers, focuses on the yuso created to hang literati portraits. Concretely, It examines yuso of seven portraits in the collection of the National Museum of Korea in order to characterize their appearance and determine their material composition. The study found that most of the yuso are sixteen-strand strings braided into a rounded cross-section(dongdahoe). The seven yuso, of which six are red and one indigo-blue, reflect the popular style associated with Joseon period literati portraits. The yuso for the portrait of Yun Geup(duksu 3503) is made from gilded paper. Analysis showed Fe particles present in a red pigment underlying the gold layer, suggesting the presence of red ochre(seokganju), an iron oxide mineral. The yuso of the portrait of Shin Im(duksu 4846) is used a paper which contains gold as well as traces of Pb, Hg and Ag. The paper in the yuso for the portrait of Yi Seongwon(bongwan 10122) mainly consisted of Ag, indicating silver paper having been used in its fabrication. The inner paper in the yuso of the portrait of Yi Seogu(sinsu 1065) is a leather combined with Ag, Fe, and Br, according to chemical analysis. The FTIR of the leather sample reveals that the spectrum in the fingerprint region is nearly identical to that of sheepskin, indicating the yuso was made from gold-coated sheepskin.

• Applied Microscopy
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• v.42 no.2
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• pp.87-93
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• 2012

In this study, fine structures of silica, titanium dioxide, talc and kaolin used in decorative cosmetics and the mixture extracted from BB cream cosmetics were observed by scanning electron microscopy. Kaolin had plate like shape structures of polygon with smooth surface and edge of kaolin had a relatively smooth appearance in comparison with talc. Also, thickness of each layer was estimated to about $0.1{\mu}M$ in the lump formed in stratum of several layers. Talc was observed by lumps shape phase of layering very thin flake. Boundary of thin flake was sharp or angular phase and thickness of flake was approximately 600 nm in diameter. When comparing the thickness of kaolin and talc, we was confirmed that kaolin was thicker than talc. Diameter of titanium dioxide was estimated to 0.2~0.3 ${\mu}M$ and surface of particle was a soft cubic form. Silica was confirmed that variety of size from 200 nm to $15{\mu}M$ of globular shape was measured. From the observation of inorganic pigments, silica was homogeneous dispersed in the BB cream cosmetics and among each other was filled with relatively small size like talc, kaolin, titanium dioxide and iron oxide. In conclusion, we suggest that silica at decorative cosmetics were formed in cosmetic coat at the skin as the minimum thickness.

• Journal of Conservation Science
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• v.37 no.5
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• pp.606-616
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• 2021

From the collection of the National Kimhae Museum, qualitative analyses using microscopic observation, SEM-EDS, Raman spectroscopy, FT-IR-ATR spectroscopy, and GC-MS were conducted on three burnished red potteries-Jeoksaekmaoyeonwa burnished red pottery (Neolithic age red pottery), Dandomaoyeonwan burnished red pottery(Bronze age red pottery) and Jeoksaekmaoyeongajimun burnished red pottery(Bronze age red pottery)-to investigate the components of the red pigments and the binder. After the layers of the primer were separated from the red surface, crystals of red pigment particles and minerals were found on the red surface. Through SEM-EDS, Raman estimates that the red pigment is Among soil pigments with iron oxide(Fe₂O₃) as the main color development source, Red Ocher(Fe₂O₃). A band characteristic of the Urushiol polymer was detected in the FTIR-ATRspectra(4000~600cm^-1), GC-MS analysis confirmed the presence of the benzenemethanol-2-prophenyl, 4-heptylphenol, 1-tetracecanol, heptafluorobutyric texidecane, all of which are the ingredients of the directional structure of the lacquer present in the red layer. Therefore, it seemed that the three burnished red pottery: Jeoksaekmaoyeonwan pottery(Neolithic age burnished red pottery), Dandomaoyeonwan pottery(bronze age burnished red pottery) and the Jeoksaekmaoyeongajimun pottery(bronze age burnished red pottery) made by mixing minerals and Red Ocher(Fe₂O₃), with lacquer.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.53-60
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• 2010

In the present study, experiments have been performed to investigate the possibility of removing Cochlodinium polykrikoides using the dredged sediment from a coastal fishery and then to derive the optimal conditions; the amount and particle size of dredged sediment besprinkled into water, the thermal treatment, the types and amounts of additives, and the depth profile of Cochlodinium polykrikoides. Results showed that the optimal amount of dredged sediment besprinkled into water was 6~10 g/L, and the removal efficiency of Cochlodinium polykrikoides after the reaction time for 60 min was 73~93%. Note that, in the real sea water, it is necessary to besprinkle 6~10 $kg/m^3$ of dry dredged sediment on a unit area (1 $m^2$). With decreasing particle size, Cochlodinium polykrikoides could be more efficiently removed. The removal efficiency was 93% with the dredged sediment smaller than 100 ${\mu}m$, whereas it was 51% with that of 100 ${\mu}m$ ${\mu}m$. Since most of dredged sediment (over 90%) was smaller than 100 ${\mu}m$, high efficiency could be obtained by besprinkling only the dredged sediment without pre-treatment. CaO was found to be an effective additive in promoting the removal efficiency (up to 99%). The optimal amount of additive was 5~10%, however, it was necessary to use as small amount of an additive as possible in order to avoid the sharp increase in pH. The removal efficiency increased with increasing depth profile of Cochlodinium polykrikoides. The removal efficiency was 83% at 5 cm depth, whereas it was 93% at 50 cm depth. In the sea water, red tide occurred within 3 m depth, and furthermore most Cochlodinium polykrikoides existed within 1 m depth. It was, therefore, expected that higher removal efficiency of Cochlodinium polykrikoides could be obtained when the dredged sediment was besprinkled into the sea water. The removal efficiency of Cochlodinium polykrikoides was up to 93% when the dredged sediment (<100 ${\mu}m$) was besprinkled into water at the ratio of 10 g/L. This result was comparable to that obtained with loess (90~97%). All the results in the present study indicated that the dredged sediment from a coastal fishery could be successfully used as a substitute of loess for removing the red tide alga.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1825-1832
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• 2000

Column experiments were conducted by using soil columns, to investigate feasibility and efficiency of in-situ ozone enhanced remediation for diesel-contaminated soil. The injection of gaseous ozone into soil column revealed the enhanced decomposition of ozone due to the catalytic reaction between ozone and metal (e.g., Fe, Mn etc.) oxides as evidenced by as much as 25 times shorter half-life of ozone in a sand packed column than in a glass beads packed column. Substantial retardation in the transport of and the consumption of ozone were observed in the diesel contaminated field soil and sand packed columns. After 16 hrs ozonation, 80% of the initial mass of diesel (as diesel range organic) concentration of $800{\pm}50mg/kg$, was removed under the conditions of the flow rate of 50mL/min and $6mg-O_3/min$. Whereas, less than 30% of diesel was removed in the case of air injection. Analysis of the residual TPH(total petroleum hydrocarbon) and selected 8 aliphatics of diesel compounds in the inlet and the outlet of the column confirmed that diesel nonselectively reacted with ozone and then shifted to lower carbon numbered molecules. Water content also was found to be an important parameter in employing ozone to the hydrocarbon-contaminated soil.