• The Journal of Engineering Geology
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• v.22 no.1
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• pp.67-81
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• 2012

The physical, chemical, and biological properties of clogging materials formed within groundwater wells in the Mt. Geumjeong area, Busan, Korea, were characterized. The particle size distribution (PSD) of clogging materials was measured by a laser analyzer. XRD, SEM, and TEM analyses were performed to obtain mineralogical information on the clogging materials, with an emphasis on identifying and characterizing the mineral species. In most cases, PSD data exhibited an near log-normal distribution; however, variations in frequency distribution were found in some intervals (bi-or trimodal distributions), raising the possibility that particles originated from several sources or were formed at different times. XRD data revealed that the clogging materials were mainly amorphous ironhydroxides such as goethite, ferrihydrite, and lapidocrocite, with lesser amounts of Fe, Mn, and Zn metals and silicates such as quartz, feldspar, micas, and smectite. Reddish brown material was amorphous hydrous ferriciron (HFO), and dark red and dark black materials were Fe, Mn-hydroxides. Greyish white and pale brown materials consisted of silicates. SEM observations indicated that the clogging materials were mainly HFO associated with iron bacteria such as Gallionella and Leptothrix, with small amounts of rock fragments. In TEM analysis, disseminated iron particles were commonly observed in the cell and sheath of iron bacteria, indicating that iron was precipitated in close association with the metabolism of bacterial activity. Rock-forming minerals such as quartz, feldspar, and micas were primarily derived from soils or granite aquifers, which are widely distributed in the study area. The results indicate the importance of elucidating the formation mechanisms of clogging materials to ensure sustainable well capacity.

• Journal of Dairy Science and Biotechnology
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• v.16 no.2
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• pp.119-136
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• 1998

The lipids of milk provide energy and many essential nutrients for the newborn animal. They also have distinctive physical properties that affect the processing of dairy products. Milk fat globules mainly consist of neutral lipids like triacylglycerols, whereas the globule membranes contain the complex lipids mostly, Phospholipids are a small but important fraction of the milk lipids and are found mainly in the milk fat globule membrane and other membranous material in the skim-milk phase. The milk fats of ruminant animals are characterized by the presence of relatively high concentrations of short-chain fatty acids, especially butyric and hexanoic acids, which are rarely found in milks of non-ruminants. The fatty acids of milk lipids arise from de novo synthesis in the mammary gland and uptake from the circulating blood. The fatty acid compositions of milks are usually complex and distinctive, depending on the nature of the fatty acids synthesized de novo in the mammary gland and those received from the diet in each species. The content and composition of milks from different species vary widely; presumably, these are evolutionary adaptations to differing environments. The actual process by which these globules are formed is unkonwn, but there are indications that triglyceride-containing vesicles which bleb from endoplasmic reticulum may serve as nucleation sites for globules. Recent studies on milk have centred on the manipulation of milk lipids to increase specific fatty acids, i.e. 20-carbon omega-3 fatty acids (eicosapentaenoic acid 20:5n3, decosahexaenoic acid 22:6n3) from marine sources because the fatty acids are closely associated with a decreased risk of coronary heart disease.

• Korean Journal of Poultry Science
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• v.28 no.2
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• pp.83-89
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• 2001

Newcastle disease virus, CBP-1 strain isolated from Korean pheasants was passaged for 173 times by 9-day-old specific pathogenic free (SPF) embryonated eggs at $37^{\circ}C$ (parent strain) and subsequently passaged for 15 (cold attenuation (CA) -15) and 30(cold attenuation (CA) -30) times by 10-day-old of commercial broiler chicks embryonated eggs at $29^{\circ}C$, respectively, The Physical and chemical properties (sensitivity to lipid solvents, low pH and thermostability), pathogenicity (mean death time, intracerebral pathogenic index and intravenous patho-genic index), safety, booster or protective effect and characterization of temperature sensitivity were measured in cold attenuated CA-15 or 30 strain and compared to those of parent CBP-1 strain. NDV, CBP-1 CA-30 strain acquired cold attenuation and decreased infectivity at $41^{\circ}C$ compared to those of parent strain grown at $37^{\circ}C$. It lost hemagglutination activity (HA) and cell infectivity at $56^{\circ}C$ for 30, 60, and 120 Min. CA-30 strain treated with ethyl ether also lost its HA and cell infectivity. Both CA-30 and parent strains exhibited a little resistant to HA at pH 3.0 glycine HCI buffer. Intracerebral pathogenic index (ICPI) and intravenous pathogenic index (IVPI) of parent strain were 1.12 and 1.45, but decreased to 0.75 and 0.00 in CA-30 strain, respectively. The safety was evaluated by mortality in chicks inoculated with 10$^{4.0}$ EID$_{50}$ /0.1 ml. The mortalities of parent, CA-30 and commercial Bl strains were 17.5, 12.0 and 0.0%, respectively. The safety of CA-30 strain was higher than that of parent strain. The booster effects of CA-30 strain and parent strain performed in 4-week-old chicks after being vaccinated with primary commercial Bl strain.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.766-773
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• 2013

A transparent film was fabricated based on bacterial cellulose (BC), BC has excellent physical strength and stability at high temperature and it is an environmental friendly flexible material. In order to improve the conductivity, silver nanowire (AgNW) and/or graphene were introduced to the BC membrane. The aspect ratio of the AgNW synthesized in this study was 214, with a length of $15{\mu}m$ and width of 70 nm. The higher aspect ratio improved the conductivity by reducing the contact resistance. The thermal and electrical properties of 7 types of films prepared were investigated. Each film was fabricated with rectangular shape ($2mm{\times}2mm{\times}50{\mu}m$). The films were scored with a net shape by a knife, and filled with AgNW and graphene to bestow conductivity. The film filled with AgNW showed favorable electrical characteristics with a thickness of $350{\mu}m$, electron concentration of $1.53{\times}10^{19}$, electron mobility of $6.63{\times}10^5$, and resistivity of 0.28. The film filled with graphene had a thickness of $360{\mu}m$, electron concentration of $7.74{\times}10^{17}$, electron mobility of 0.17, and resistivity of 4.78. The transmittances at 550 nm were 98.1% and 80.9%, respectively. All the films were able to light LEDs bulbs although their brightness differed. A thermal stability test of the BC and PET films at $150{\pm}5^{\circ}C$ showed that the BC film was more stable, whereas the PET film was quickly banded. From these results, it was confirmed that there it is possible to fabricate new transparent conductivity films based on BC.

• Clean Technology
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• v.24 no.3
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• pp.198-205
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• 2018

This study investigated the influence of catalyst preparation on the activity of $Co-CeO_2$ catalyst for $N_2O$ decomposition. $Co-CeO_2$ catalysts were synthesized by co-precipitation and incipient wetness impregnation. In order to estimate the performance of the as prepared catalysts, direct catalytic $N_2O$ decomposition test was carried out under $250{\sim}375^{\circ}C$. As a result, the catalyst prepared by co-precipitation (CoCe-CP) showed an enhanced performance on $N_2O$ decomposition reaction even in the presence of $O_2$ and/or $H_2O$, whereas the impregnation catalyst (CoCe-IM) did not. In order to investigate the difference in catalytic activity, characterization such as XRD, BET, TEM, $H_2-TPR$, $O_2-TPD$, and XPS was conducted. It is confirmed that the particle size and specific surface area were changed depending on the catalyst preparation method and the synthesis process influenced the physical properties of the catalysts. In addition, the improvement in the activity of the catalyst prepared by co-precipitation is due to the enhanced reduction from $Co^{3+}$ to $Co^{2+}$ and the improved oxygen desorption rate. However, it has been confirmed that the surface electron state and binding energy, which are related to $N_2O$ decomposition, do not change depending on the preparation method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.228-234
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• 2016

The aim of this study was to develop pharmaceutical dosage forms with a bi-phasic drug using a double extrusion approach. Hot melt extrusion was performed using a co-rotating twin-screw extruder. The. 1st melt extrusion was performed using polymer with a relatively higher Tg, such as HPMC and the 2nd melt extrudate was obtained using the 1st extrudate and polymers with a lower Tg, such as HPMC-AS and PEO. In addition, the formulation with all the content in the same proportion as the double extudate was produced using single extrusion for comparison. Physical characterization was performed on the formulations employing differential scanning calorimetry (DSC). In vitro release tests were studied using a USP Type-I apparatus at $37{\pm}0.5^{\circ}C$ and 100 rpm. The similarity factor (f2) was also used to check the difference statistically. The DSC results indicated that the crystallinity of ibuprofen was changed to an amorphous state after extrusion in both double and single melt extrusion. Double melt extrudate with ibuprofen showed the desired release in acidic media (pH 1.2) in the first two hours and basic (pH 6.8) during six hours. Double melt extrudate with glimepiride showed faster release in 60 min of over 80%, whereas the single extrudate with glimepiride showed retarded release due to the interaction with HPMC. The similarity factor(f2) value was 28.5, which demonstrates that there were different drug release behavior between the double and single extrusion. Consequently, the double melt extrudated formulation was robust and gave the desired drug release pattern.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.636-648
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• 2010

Two types of wild grape extracts(WGE) prepared by different methods were added into butter-top bread at different concentrations(0, 5, 10, 15, 20% of water). Then, the resulting breads were analyzed for their physicochemical and sensory properties in order to identify whether or not the WGE-enriched breads were comparable to control bread in terms of qualities and preferences. Wild grape sugar mixture(WGS), which was prepared by osmotic dehydration of wild grape fruits with the same amounts of sugar, presented significantly lower moisture content and titratable acidity as well as higher pH and sugar content compared to wild grape juice(WGJ), which was produced by boiling the fruits in a vacuum jar and squeezing. The pH of the doughs and breads containing WGE tended to decrease with increasing amounts of WGE, and this phenomenon was more appreciable in those containing WGJ than WGS. This was presumably due to the higher contents of tartaric acid in WGJ. For both types of extracts, hardness, gumminess, and chewiness of the doughs decreased with the addition of WGE, nevertheless, which properties were not remained in the resulting breads. This could be partially attributed to the relatively high degree of baking loss and lower pH of the WGE-enriched breads than those of control bread. Contrary to the mechanical analyses, the sensory properties of the breads were dependent on the WGE type. That is, WGJ-enriched bread showed lower consistency and moistness than control bread, which consequently led to relatively lower overall acceptability. However, WGS addition did not adversely affect the sensory properties of the bread. In particular, addition of 5% WGS somewhat improved the physical and sensory qualities of the bread. Thus, WGE-enriched bread could be produced without loss of bread quality when prepared with 5% WGS.

• Korean Journal of Veterinary Research
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• v.9 no.1
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• pp.23-62
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• 1969

Throughout the studies the following experimental results were obtained and are summarized: 1. Multiplication of agents in primary cell cultures of both GF classical and CR-64 acute strain of Marek's disease infected chicken kidneys was accompanied by the formation of distinct transformed cell foci. This characteristic nature of cell transformation was passaged regularly by addition of dispersed cell from infected cultures to normal chicken kidney cell cultures, and also transferred was the nature of cell transformation to normal chick-embryo liver and neuroglial cell cultures. No cytopathic changes were noticed in inoculated chick-embryo fibroblast cultures. 2. The same cytopathic effects were noticed in normal kidney cell monolayers after the inoculation of whole blood and huffy coat cells derived from both forms of Marek's disease infected chickens. In these cases, however, the number of transformed cell foci appearing was far less than that of uninoculated monolayers prepared directly from the kidneys of Marek's disease infected chickens. 3. The change in cell culture IS regarded as a specific cell transformation focus induced by an oncogenic virus rather than it plaque in slowly progressing cytopathic effect by non-oncogenic viruses, and it is quite similar to RSV focus in chick-embryo fibroblasts in many respects. 4. The infective agent (cell transformable) were extremely cell-associated and could not be separated in an infective state from cells under the experimental conditions. 5. The focus assay of these agents was valid as shown by the high degree of linear correlation (r=0.97 and 0.99) between the relative infected cell concentration (in inoculum) and the transformed cell foci counted. 6. No differences were observed between the GF classical strain and the CR-64 acute strain of Marek's disease as far as cell culture behavior. 7. Characterization of the isolates by physical and chemical treatments, development of internuclear inclusions in Infected cells, and nucleic acid typing by differential stainings and cytochemical treatments indicated that the natures of these cell transformation agents closely resemble to those described fer the group B herpes viruses. 8. Susceptible chicks inoculated with infected kidney tissue culture cells developed specific lesions of Marek's disease, and in a case of prolonged observation after inoculation (5 weeks) the birds developed clinical symptoms and gross lesions of Marek's disease. Kidney cell cultures prepared from those inoculated birds and sacrificed showed a superior recovery of cell transformation property by formation of distinct foci. 9. Electron microscopic study of infected kidney culture cells (GF agent) by negative staining technique revealed virus particles furnishing the properties of herpes viruses. The particle was measured about $100m{\mu}$ and, so far, no herpes virus envelop has been seen from these preparations. 10. No relationship of both isolates to avian leukosis/sarcoma group viruses and PPLO was observed.