• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.46-52
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• 2005

A marine environmental information system (MEIS) useful for optimal route planning of ships running in the ocean was developed. Utilizing the simulated marine environmental data produced by the European Center for Medium-Range Weather Forecasts based on global environmental data observed by satellites, the real-time forecast and long-term statistics of marine environments around planned and probable ship routes are provided. The MEIS consists of a land-based data acquisition and analysis system(MEIS-Center) and a onboard information display system(MEIS-Ship) for graphic description of marine information and optimal route planning of ships. Also, it uses of satellite communication system for data transfer. The marine environmental components of winds, waves, air pressures and storms are provided, in which winds are described by speed and direction and waves are expressed in terms of height, direction and period for both of wind waves and swells. The real-time information is characterized by 0.5° resolution, 10 day forecast in 6 hour interval and daily update. The statistic information of monthly average and maximum value expected for a return period is featured by 1.5° resolution and based on 15 year database. The MEIS-Ship include an editing tool for route simulation and the forecasting and statistic information on planned routes can be displayed in graph or table. The MEIS enables for navigators to design an optimal navigational route that minimizes probable risk and operational cost.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.111-126
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• 1997

I concluded as follows after analyzing the problem of the curriculum in the Department of Optical Science at a college of professional education for the purpose of training desireable opticians. The years required for competing a course of study at the Department of Optical Science at a college of professonal education have to be extended from the present two school years to three years for the short run and have to be extended to four years for the long run. The distribution ratio of subjects in the slate examination should be readjusted and the field of contect lens. Also the system of the slate examination should strengthen by adding practical processing test with the present selective written examination. The Curriculum of department of Optical Science curriculum at a college of professional education should be reorganized reinforce experiment and practice, namely, the subject for experiment and practice, such as Making of specific glasses and Test method of phorpter etc, should be reinforced. The knowledge for goods should be included in clinical training and it is reasonable to constitute the theory vs the practice in the ratio of five to five. The number of the Department of Optical Science should be increased two or more for per forty students and it is desirabled that only the professors who major optical Science or opthalmic medical science, or have Optician Licence should give lecture. The experiment a practice should be enlarged and it is necessary to secure or to adopt practice hours, practice site, machinery and parts, practice assistant and etc. It is reasonable that clinical training include the knowledge of goods, business practice and etc. and that a practice examiner has the qualification as an optician who has education background higher that the college of professional education.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3990-3996
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• 2014

Because the physical properties can be decreased when a Nylon 66/glass fiber composite is injected into a mold over $300^{\circ}C$, a systematic study of the thermal history in the case of re-use is needed. Nylon 66/glass fiber extrudates as a function of the extrusion number were prepared using a twin screw extruder at 305/290/273/268/265/$260^{\circ}C$. The chemical structure, thermal properties, melt index, crystal structure, Izod impact strength, and rheological properties were measured by Fourier transform infra-red (FT-IR), melt indexer, DSC, TGA, XRD, Izod impact tester, and dynamic rheometer. The FT-IR spectra indicated that the number of extrusions did not affect the chemical structure. The decrease in molecular weight with increasing extrusion number was confirmed by the melt index and the complex viscosity of extrudates. Based on the DSC and TGA results, the thermal history had no effect on the melting temperature, regardless of the number of extrusions, but the degradation temperature decreased up to $20^{\circ}C$ with increasing extrusion number. The Izod impact strengths of the extrudates were found to decrease with increasing extrusion number. No structural change after extrusion was also confirmed because there was no change in the slope and shape of the G'-G" plot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.334-341
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• 2016

In this paper, the study of a waveguide aperture-coupled feed-structured antenna has been conducted for the purpose of applying it to a wireless back-haul system sufficient for high-capacity gigabits-per-second data rates. For this study, a $32{\times}32$ waveguide slot sub-array antenna with a corporate-feed structure was designed and produced. Also, this antenna is used at 57 GHz to 66 GHz in the V-band. The construction of the antenna is a laminated form with radiating parts (outer groove and slot, cavity), a coupled aperture, and feeds in each. The antenna was designed with HFSS, which is based on 3D-FEM, produced with aluminum processed by a precision-controlled milling machine, and assembled after a silver-plating process. The measurement result from analysis of the characteristics of the antenna shows that return loss is less than -12 dB, VSWR < 2.0, and a wide bandwidth ranges up to 16%. An overall first side lobe level is less than -12.3 dB, and a 3 dB beam width is narrow at about $1.85^{\circ}$. Also, antenna gain is 38.5 dBi, offering high efficiency exceeding 90%.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.268-273
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• 2008

For evaluation of immune stimulation effect of lacquer tree extracts, lymphocytes were counted by labeling of FITC-conjugated monoclonal antibody in the pheripheral blood of pigs that fed with a fodder supplemented by lacquer tree extracts. Populations of MHC-II+, CD4+, and CD8+T lymphocytes were increased more than 2% level after 1 week feed supply of the lacquer tree extracts. The increase of those T cells reached at maximum level after 2 weeks in the tested group. B lympyocytes with surface IgM were increased 5% after 1 week feed supply of the lacquer tree extracts, and their numbers reached maximum after 2 weeks in the tested group. For the assessment of cytotoxicity of the lacquer tree extracts, morphological changes were examined on the epithelial cells of small intestine from pigs fed with a fodder supplemented by 0.1 % lacquer tree extracts for 6 weeks (the tested group). Thin-sectioned tissue of small intestine was fixed with glutaraldehyde, then coated with gold particles, and the specimen was examined under scanning electron microscope. The villi on the mucus membrane of jejunum and ileum from the tested pigswere enlarged on the tip and were linked each other.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.823-829
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• 2002

The composite frame system with reinforced concrete column and steel beam has some advantages in the structural efficiency by complementing the shortcomings between the two systems. The system, however has also a lot of problems in practical design and construction process due to the material dissimilarities. Considering these circumstances, this research is aimed at the development of the composite structural system which enables the steel beams to be connected to the R/C columns with higher structural safety and economy. Basically the proposed connection system is composed of four split tees, structural angles reinforced by stiffener, high strength steel rods, connecting plates and shear plates. The structural tests have been carried out to verify the moment transfer mechanism from beam flange to steel rods or connecting plates through the angle reinforced by siffener. The four prototype specimens have been tested until the flange of beam reached the plastic states. From the tests, no distinct material dissimilarities between concrete and steel have been detected and the stress transfer through wide flange beam - structural angle - high strength steel rod or connecting plate is very favorable.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1337-1342
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• 2008

This study was conducted to investigate effects of chemical sanitizers on inhibiting foodborne pathogens, such as Listeria monocytogenes (L. monocytogenes), Salmonella Typhimurium (S. Typhimurium), and E scherichia coli O157:H7 (E. coli O157:H7), on cabbages. Cabbages were inoculated with the culture cocktail of pathogens and treated with water, 100 ppm commercial chlorine, and 50, 100, and 200 ppm chlorine dioxide ($ClO_2$) for 1, 5, and 10 min at room temperature ($22{\pm}2^{\circ}C$). Treatments with water did not significantly reduce levels of three pathogens whereas other treatments with chemical sanitizers significantly reduced levels of three pathogens. Treatment with 200 ppm $ClO_2$ for 10 min was the most effective at inhibiting pathogens and reduction levels were 1.90, 1.92, and 1.98 log CFU/g for L. monocytogens, S. Typhimurium, and E. coli O157:H7, respectively. Levels of reduction were increased with the increase of $ClO_2$ concentrations. When chemically injured cells were investigated, there were no significant differences on the levels of injured cells between before and after treatment with commercial chlorine and $ClO_2$. These results suggest that $ClO_2$ can be used as an alternative sanitizer for reducing pathogens on fresh produces.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1025-1029
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• 2008

Fresh green tea leaf extracts were prepared by different enzyme treatment conditions, such as concentration, treating time and treating temperature using complex enzyme, Rapidase TF, and then extracted for 30 min at $80^{\circ}C$ to investigate their physicochemical properties. The results showed that free sugar content in every sample tended to increase, especially glucose content was increased up to 7.25 times compared to the control. Total amino acid was barely affected by the enzyme treatment and caffeine content was increased with reaction temperature. Total polyphenol and total catechin content was increased according to the amount of enzyme added and reaction temperature. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin gallate by descending order of the content. Gallic acid content increased up to 0.04% and $45^{\circ}C$ with no further significant changes thereafter. From the results above, we could conclude that a simple and new method to extract green tea materials directly from fresh green tea leaves with improved extract ratio may be introduced by adding $0.08{\sim}0.1%$ of Rapidase TF to heat treated fresh green tea leaves and keeping temperature at $37{\sim}45^{\circ}C$ for $180{\sim}240\;min$ in order to skip existing complicated procedures.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.513-519
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• 2006

We developed two kinds of the microchip for application to electrophoresis based on both glass and quartz employing the MEMS fabrications. The poly-Si layer deposited onto the bonding interface apart from channel regions can play a role as the optical slit cutting off the stray light in order to concentrate the UV ray, from which it is possible to improve the signal-to-noise (S/N) ratio of the detection on a chip. In the glass chip, the deposited poly-Si layer had an important function of the etch mask and provided the bonding surface properly enabling the anodic bonding. The glass wafer including more impurities than quartz one results in the higher surface roughness of the channel wall, which affects subsequently on the microflow behavior of the sample solutions. In order to solve this problem, we prepared here the mixed etchant consisting HF and $NH_4F$ solutions, by which the surface roughness was reduced. Both the shape and the dimension of each channel were observed, and the electroosmotic flow velocities were measured as 0.5 mm/s for quartz and 0.36 mm/s for glass channel by implementing the microchip electrophoresis. Applying the optical slit with poly-Si layer provides that the S/N ratio of the peak is increased as ca. 2 times for quartz chip and ca. 3 times for glass chip. The maximum UV absorbance is also enhanced with ca. 1.6 and 1.7 times, respectively.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.453-458
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• 2009

Recently, new methods to synthesize and process polymers without toxic organic solvents are needed in order to solve environmental problems. The use of supercritical carbon dioxide as a solvent for the polymer synthesis is attractive since it is non-toxic, non-flammable, naturally abundant, and the product may be easily separated from the solvent. In this study, we developed the method using super critical $CO_2$ to prepare P(MAA-co-EGMA) hydrogel nanoparticles as an intelligent drug delivery carrier. The effects of concentrations of PtBuMA-PEO as a dispersion stabilizer and AIBN as an initiator on the particle synthesis were investigated. When PtBuMA-PEO concentration increased, the particle size decreased. However, there was no significant difference in the particle size according to the AIBN concentration. There was a drastic change of the equilibrium weight swelling ratio of P(MAA-co-EGMA) hydrogel nanoparticles at a pH of around 5, which is the $pK_a$ of PMAA. At a pH below 5, the hydrogels were in a relatively collapsed state but at a pH higher than 5, the hydrogels swelled to a high degree. In release experiments using Rh-B as a model solute, the P(MAA-co-EGMA) hydrogel nanoparticles showed a pH-sensitive release behavior. At low pH(pH 4.0) a small amount of Rh-B was released while at high pH(pH 6.0) a relatively large amount of Rh-B was released from the hydrogels.