• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.105-114
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• 2004

Consolidation characteristics have been investigated by using Rowe cell consolidation tester for dredged soil, which is more than two times as much as the liquid limit. To examine the effects of variation of water content on consolidation characteristic, tests were carried out varying the initial water content from $100\%\;to\;150\%.$ The results were compared with the consolidation characteristics of remolded clay. The test results showed that the hither the initial water content of dredged clay was, the more noticeable the non-linear behavior of e-log P curves occurred. The variation of the gradient was apparent to load stage 40kPa and became less apparent after load stage 80kPa on the e-log P curves. Ratio of compression index stayed within the range suggested by Mesri and variation of initial water content has hardly influenced the coefficient of consolidation. On the contrary, it was found that the magnitude of consolidation load affects the vertical coefficient of consolidation. The variation of stratum thickness during consolidation processing needs to be taken into consideration since hydraulic fill would go through a much larger scale strain than land soil when it is subject to a load. In this study, the consolidation period considering the variation of stratum thickness was analyzed and the results were compared with those of existing consolidation studies which did not consider the variation of stratum thickness. According to the results of the study, the consolidation period of the ground with a larger strain was calculated more close to observed value in case of Mikasa theory which takes the variation of stratum thickness into consideration.

• Korean Journal of Optics and Photonics
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• v.21 no.2
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• pp.61-68
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• 2010

Optical simulation methods were applied to the edge-lit LED backlight for LCD TV applications in order to optimize the optical structure of the light guide plate(LGP), and thus to improve the uniformity properties by removing the bright spots caused by LED's. The edge-lit LED backlight consisted of three white LED's with a lamp cover, a light guide plate, and a reflection film. When there was no pattern on the entrance side surface of the LGP, the illuminance uniformity was sensitively dependent on the distance d between the LED and the entrance surface. The illuminance uniformity increased with d but its increasing rate slowed down when d was beyond ~ 1.5 mm. When micro-patterns such as a lenticular lens array (LLA) or a serration pattern were formed on the entrance surface, the illuminance uniformity was improved substantially even for the case of very small d. At the same simulation condition, the lightguide with serration pattern showed a better uniformity than that with LLA pattern. Additional improvement could be achieved by changing the refractive index of the micro-patterns. These results suggest that using micro-patterns is a very effective way to reduce the bright spots due to their refracting function for the concentrated incident rays onto the LGP.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.988-991
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• 1998

Plasma proteins were obtained from bloods of slaughtered bovine and porcine and analyzed by Fast Protein Liquid Chromatography (FPLC). Serum albumin content decreased in the following order: Porcine Plasma Protein (PPP)> Bovine Plasma Protein (BPP)> Whey Protein Concentrate (WPC). Protein contents of BPP, PPP, and WPC determined by Kjeldahl method were 85.79%, 82.30%, and 84.38%, respectively. Compared to WPC, plasma proteins had higher emulsifying activity index (EAI) below 2% protein concentration and slightly lower EAI above 4% protein concentration. Plasma proteins had higher EAI in the acidic pH range and more dependence on NaCl than WPC. Also, EAI of plasma proteins with NaCl was higher in the acidic range than that of WPC. These results indicated that plasma protein can be utilized as a raw material for emulsifier.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.1-4
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• 2006

Method of analyzing sodium alginate in foods was developed using high performance liquid chromatography (HPLC). HPLC conditions for sodium alginate were: column, MCI GEL $(8\;mm\;i.d{\times}300\;mm)$; mobile phase, deionized water; detector, refractive index detection (sensitivity = 16). Separation of sodium alginate was achieved within 15 min. Sodium alginate showed good linear relationship at 0.1-2.0% range. Correlation coefficient of calibration curve for sodium alginate exceeded 0.999, and detection limit was 0.005%. Recovery rate of sodium alginate in wheat flour dough was 106.67%. This method was successfully applied to analyses of cereals, saccharides, and ice cream, etc. Sodium alginate was detected in chocolate, noodles, and kelp at 0-44.8% range.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.669-673
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• 2003

We fabricated a buried-ridge waveguide laser diode (B-RWG LD) which has more advantages for obtaining lateral single mode operation on the same ridge width and for the planarization of the device surface, compared to the conventional RWG LD. In this LD, the difference of the lateral effective refractive index can be controlled by the thickness of the InGaAsP layer which is grown on the active and the p-InP layers. The InGaAsP multiple quantum well was grown on a n-InP substrate by the CBE. The buried ridge structure was formed by selective wet etchings, followed by liquid phase epitaxy methods. The fabricated LD with the ridge width of 7 ${\mu}{\textrm}{m}$ showed a linear increase of the optical power up to 20 ㎽ without any kinks and a saturated output power of more than 80 ㎽. By measuring the far field pattern, we demonstrate that LDs with the ridge widths of 5 ${\mu}{\textrm}{m}$ and 7 ${\mu}{\textrm}{m}$ were operated in a lateral single mode up to 2.7I$_{th}$ and 2.4I$_{th}$, respectively.ely.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.244-252
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• 2019

This study investigated the effect of addition of aromatics such as Toluene/LCO/resin on the coke depression and asphaltene conversion. The experiment was carried out with vacuum residue as a feedstock with Molybdenum dispersed catalysts under the slurry-phase hydrocracking condition (Temp. of $425^{\circ}C$, $H_2$ pressure of 80 bar at $80^{\circ}C$, reaction time of 4 hr, Mo-concentration of 500 ppm). As results, the coke reduction was shown to be similar irrespective of types of aromatics, while asphaltene was more converted to gas and maltene when LCO and resin with higher dipole moment were added. The addition of aromatics with change of reaction time showed no difference in terms of depression of coke formation. But the addition of LCO rather increased the coke yield after 2 hr. And it was found that asphaltene in liquid phase had the higher aromaticity index so that asphaltene is difficult to disperse in oil phase.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.6
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• pp.348-354
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• 2020

Oryeong-san (ORS) is a traditional Korean herbal medicine widely used for renal associated diseases, composed of five medicine herbs; Atractylodes japonica Koidzumi, Cinnamomum cassia Presl, Polyporus umbellatus Fries, Poria cocos Wolf and Alisma orientale Juzepzuk. We studied to improve the convenience of intake and portability by developing modernized dosage forms, and examined the effect on anti-inflammation of ORS. In order to develop the tablet formulation of ORS (ORS-F), the tablets were evaluated on the basis of physical characteristics include diameter, thickness, weight variation, hardness, friability and disintegration. To analyze the marker components of ORS-F, eight index markers from five herbal medicines were chosen. And the method using high performance liquid chromatography (HPLC) with diode-array detector method was established for the simultaneous analysis. The biological activities were examined the effect of ORS-F on pro-inflammation mediated by LPS-stimulation. The production of nitric oxide (NO) and cytokines were determined by reacting cultured medium with griess reagent and enzyme-linked immunosorbent assay (ELISA). The expression of cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS) were investigated by Western blot and RT-PCR. The anti-oxidant activities of OJS-F increased markedly, in a dose-dependent manner. and, The total phenolic compound and flavonoids contents of OJS-F were 10.20±0.09 ㎍/㎎ and 12.86±0.86 ㎍/㎎. OJS-F which is LPS has diminished in the LPS-induced release of inflammatory mediators (NO, iNOS, COX2 and PGE2) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) from the RAW264.7 macrophages. Therefore, the developed formulation for tablet of ORS-F provide efficiency and usability, and indicated effect of anti-inflammation.

• Animal Bioscience
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• v.35 no.2
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• pp.224-235
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• 2022

Objective: Cage rearing has critical implications for the laying duck industry because it is convenient for feeding and management. However, caging stress is a type of chronic stress that induces maladaptation. Environmental stress responses have been extensively studied, but no detailed information is available about the comprehensive changes in plasma metabolites at different stages of caging stress in ducks. We designed this experiment to analyze the effects of caging stress on performance parameters and oxidative stress indexes in ducks. Methods: Liquid chromatography tandem mass spectrometry (LC/MS-MS) was used to determine the changes in metabolites in duck plasma at 5 (CR5), 10 (CR10), and 15 (CR15) days after cage rearing and traditional breeding (TB). The associated pathways of differentially altered metabolites were analyzed using Kyoto encyclopedia of genes and genomes (KEGG) database. Results: The results of this study indicate that caging stress decreased performance parameters, and the plasma total superoxide dismutase levels were increased in the CR10 group compared with the other groups. In addition, 1,431 metabolites were detected. Compared with the TB group, 134, 381, and 190 differentially produced metabolites were identified in the CR5, CR10, and CR15 groups, respectively. The results of principal component analysis (PCA) show that the selected components sufficiently distinguish the TB group and CR10 group. KEGG analysis results revealed that the differentially altered metabolites in duck plasma from the CR5 and TB groups were mainly associated with ovarian steroidogenesis, biosynthesis of unsaturated fatty acids, and phenylalanine metabolism. Conclusion: In this study, the production performance, blood indexes, number of metabolites and PCA were compared to determine effect of the caging stress stage on ducks. We inferred from the experimental results that caging-stressed ducks were in the sensitive phase in the first 5 days after caging, caging for approximately 10 days was an important transition phase, and then the duck continually adapted.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.5
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• pp.333-338
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• 2022

The single jet of decane/methylcyclohexane mixed fuel that is surrogate for kerosene was injected into supercritical environment and visualized using shadowgraph technique. The injection pressure drop of the fuel jet of T_r = 0.484 was kept constant at 0.5 MPa and the experiment was conducted above the critical point of the mixed fuel, and the reduced temperatures of the chamber was changed from 1.00 to 1.23, and the reduced pressures was 1.00 and 1.38. As an index for reducing the density of jets sprayed into the supercritical environment, the brightness intensity of the post-processed jet image was observed with the internal temperature and pressure of the chamber. It was confirmed that the decrease in the brightness intensity of the jet when the temperature inside the chamber increased, and when the pressure inside the chamber was higher at the same temperature, the decrease in the brightness intensity of the jet was delayed. When the pressure inside the chamber is high, it is thought that the change in brightness intensity is delayed due to the increase in the pseudo-critical temperature of the fuel and the increase in the temperature required to reduce the density of the fuel jet.

• Journal of the Mineralogical Society of Korea
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• v.5 no.2
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• pp.109-121
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• 1992

For the purpose of mineralogical and chemical study on the topazes from various localities of world(Brzail, China, India, Nigeria and Sri Lanka), electron microprobe analysis(EPMA), neutron activation analysis(NAA), X-ray diffractometry, Raman spectroscopy, etch test, scanning electron microscopy, refractive index, specific gravity, fluid inclusion were performed. The chemical composition in topaz was discussed along with its physical and structural properties. Variations in the unit-cell dimension and physical properties of topaz were found to have a close relations in the unit-cell dimension and physical properties of topaz were found to have a close relationship with extent of substitution of $OH^-\;for\;F^-$. According to neutron activation analyses, the trace elements had no effects on the physical properties of topaz. Raman spectra showed that the peaks of topaz were different in intensity from one locality to another. Etching defects in topaz includes negative crystal defect o point-bottom pit(India, Nigeria) and net work defect of curl-bottom pit(Brazil, China). Fluid inclusions in topaz may be classiffied into liquid $CO_2$-bearing inclusion, gaseous inclusion, halite, sylvite-bearing inclusion and liquid inclusion. The results of this study can be useful to devising artificial coloring methods for topaz with different mineralogical compositions.