• YAKHAK HOEJI
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• v.31 no.3
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• pp.182-188
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• 1987

Simple coacervation of bovine serum albumin was studied to prepare biodegradable microacapsule. Albumin microcapsules were prepared by using acrylonitrilestyrene polymer (M-80) resin beads and sulfamethoxydiazine as the core materials. The albumin to beads ratio was found to be 1:2.3 and the albumin to sulfamethoxydiazine ratio to be 1:2.9. The 50% release times (T$_{50%}$) of sulfamethoxydiazine and microencapsulated sulfamethoxydiazine were 6 min. and 73 min., respectively. The surface appearance of the microcapsule collected after release experiment was not different from those of the original microcapsule. In addition to slowing release of drug the microencapsulation process masked characteristic bitter taste of sulfamethoxydiazine.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.93-96
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• 2004

In this paper we introduce a new escalator(ESC) structure-based adaptation algorithm. The proposed algorithm is independent of eigenvalues spread ratio(ESR) of channel and has faster convergence speed than that of the conventional ESC algorithms. This algorithm combines the fast adaptation ability of least square methods and the orthogonalization property of the ESC structure. From the simulation results the proposed algorithm shows superior convergence speed and no slowing down of convergence speed when we increase the ESR of the channel.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.75-78
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• 2003

This study is to investigate the probability to develop the AE Water-reducing agent which can decrease the bleeding by mixing melamine type super-plasticizer(SP) and methyl cellulose(MC) viscosity agent. According to the result, as the mixing ratio of melamine type SP and MC viscosity agent increases, the bleeding is reduced due to a increase of the air content. When the mixing ratio of melamine type SP and MC viscosity agent is 1:2 and 1;3 at the water content of 165kg/$m^3$ and 175kg/$m^3$ respectively, slump and air content are satisfied and bleeding is reduced to some extent, so this is determined as the mixing ratio of AE water reducing agent for reduction of bleeding. It is prove that the developed AE water reducing agent for reduction of bleeding can reduce the amount of bleeding and prohibit the plastic shrinkage crack by slowing down the bleeding speed. Compressive strength of hardened concrete does not make any difference in comparison with plain concrete.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.334-338
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• 2001

In order to investigate the effects of various injection hole shapes on the film cooling of turbine blade, three test models having cylindrical and shaped holes were used. A three-dimensional Navier-Stokes code with standard k-$\epsilon$ model was used to compute the film cooling coefficient on the film cooled turbine blade. Over 330,000 grids were used to compute the flow over the blade. Mainstream Reynolds number based on the cylinder diameter was $7.1{\times}10^4$. The turbulence intensity kept at $5.0\%$ for all inlets. The effect of coolant blowing ratio was studied for various blowing ratios. For each blowing ratios, wall temperatures around the surface of test model were calculated. Temperature was visualized using cartesian cut-cell method to obtain traces of the injected secondary air on the test surface, so we could interpret the film effectiveness as temperature distributions.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.99-107
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• 2019

This paper analyzed the characteristics of population change from 2000 to 2018 in 466 mountainous areas using resident registration data from the Ministry of the Interior and Safety, and projected the population in those areas through 2050 with the cohort change ratio method. The population had dramatically decreased from 2000 to 2009. With the slowing population decrease after 2010, the population has increased gradually since 2014. Especially the population of ages over 65 in 2018 had increased 34% compared to 2000, while the working age population had decreased 29%. This shows that population aging becomes serious problems in the mountainous area. Assuming the cohort change ratios from 2010 to 2015 and child-woman ratio in 2015 remain constant, it appeared that the projected population of the mountainous area dropped to 1.26 million in 2030 and 820,000 in 2050. It is expected to have a population with an inverted pyramid structure showing a gender imbalance with more females in 60's and 70's. Although it continues to show the recent population growth in mountainous area, population in mountainous area is expected to consistently decrease. Therefore, it is required to develop policies and strategies to promote an influx of people into mountainous area for maintaining functionality and sustainability of mountainous areas.

• Steel and Composite Structures
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• v.36 no.6
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• pp.657-669
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• 2020

This study investigates the fire resistance characteristics of reactive powder concrete according to changes in the cement content per unit area, mixing ratio of metakaolin (MK), and content of polypropylene fiber. A fire test was conducted, and the resulting residual strength characteristics were investigated through flexural and compressive strength measurements, as well as condition rating classification based on visual evaluation. MK effectively reduced the initial high content of calcium hydroxide, thereby reducing the water vapor pressure generated during pyrolysis and slowing spalling. Furthermore, the pore structure and loose tissue were effective for relieving the water vapor pressure in the event of a fire.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1287-1300
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• 2017

Based on the observation that ignoring the angle dependency of multigroup resonance cross sections within a fuel pellet would result in nontrivial underestimation of the spatial self-shielding of flux, a parametrized spectral superhomogenization (SPH) factor library (PSSL) method is developed as a practical means of resolving the problem. Region-wise spectral SPH factors are calculated by the normal and transport corrected SPH iterations after ultrafine group slowing down calculations over various light water reactor pin-cell configurations. The parametrization is done with fuel temperature, U-238 number density, fuel radius, moderator source represented by ${\Sigma}_{mod}V_{mod}$, and the number density ratio of resonance nuclides to that of U-238 in a form of resonance interference correction factors. The parametrization is successful in that the root mean square errors of the interpolated SPH factors over the fuel regions of various pin-cells are within 0.1%. The improvement in reactivity error of the PSSL method is shown to be superior to that by the original SPH method in that the reactivity bias of -200 pcm to -300 pcm vanishes almost completely. It is demonstrated that the environment effect takes only about 4% in the reactivity improvement so that the pin-cell based PSSL method is effective in the assembly problems.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.6
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• pp.39-45
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• 2016

In this paper, analyzes the characteristics of self-weight consolidation on the dredged clay according to the fines content and falling height. Research was performed with the dredged clay sampled by Sae-mangeum field site. Classification of fines content was performed by sieve analysis test. After adjusting the fine content, self-weight consolidation tests were carried out focussing on the variation of fines content and falling heights. From the test results of the self-weight consolidation test, samples with high fines content had reached sedimentation completion more later than ones with less fine content samples. In other words, the start of self-weight consolidation was slowing down with increasing of fines content. Also, from the test results of calculating the coefficient of sedimentation consolidation, the coefficient value were increased with the fines content increases. In addition, the change of sedimentation ratio and volume ratio showed more higher changed value as the fine content increases. Thus, it is important to consider the fines content when estimate the settlement time of dredged soil in field dredge work.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.73-81
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• 2004

On this study, durability decreasing element caused by salt damage was analyzed elementally and studied with the data of the inside and outside in the country. The design strength and water-cement ratio according to diffusion coefficients of chloride were applied to Fick's diffusion equation. The required over depended on environmental conditions is estimated with endurance period, and the influences on cover according to the transformation of the each parameter were investigated. In consequence, if water-cement ratio decreases and design strength increases, it shows that slowing infiltration velocity of chloride ion can decrease required cover. Especially, it is more effective to use Portland blast-furnace slag cement into high strength concrete in the splash zone environmental conditions in blocking the diffusion of chloride ion. As the result, in the case of the offshore concrete structure needed high durability, it is needed to increase cover($3cm{\sim}8cm$) than minimum standard cover(8cm) according to environmental conditions.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.212-215
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• 2005

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy in clinical practice, with a 0.1% life time risk in the general population. Conventional neurophysiological studies have been useful in the diagnosis of this condition, as have a number of more specialized procedures. Therefore, we evaluated the diagnostic sensitivities of several parameters in nerve conduction technique for CTS patients. We analyzed 100 patients (159 hands) who were diagnosed with CTS clinically and electrophysiolosically. Median motor and sensory nerve conduction velocities (MCV and SCV) with wrist, palm, and finger stimulation were performed in traditional methods. Sensitivities of each test were calculated and compared to normal control data. The sensitivities of existing nerve conduction method were noted in terminal latency on median nerve, 2nd finger-wrist segment, 3rd finger-wrist segment, palm-wrist segment and distoproximal ratio, as 72.96%, 92.45%, 94.34%, 94.97%, and 97.48%, respectively. In the early course of CTS, sensory nerve conductions in the median nerve are more valuable than motor nerve conduction. Sensory nerve conductions are usually affected before motor nerve conductions in CTS. In this study, we detected that slowing of median SCV was the most frequent in the distoproximal ratio.