• Journal of the Korean Wood Science and Technology
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• v.41 no.5
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• pp.447-455
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• 2013

Hemicellulose extract obtained by pre-pulping extraction of woodchips, is very diluted acidic in nature. The major component responsible for this weak acidity is acetic acid, present in levels up to 5~10 g/L. Here, we report an exploratory study on the extract upgrading by reactive solvent extraction of acetic acid as well as ASPEN simulation. In this study, liquid-liquid equilibria for the ternary systems (water + acetic acid + ethyl acetate) were measured at the temperature of 298.15 K and 10 (pH = 2.02), 5 (pH = 2.17), and 1 (pH = 2.48) percent of acetic acid samples were used to carry out liquid-liquid extraction studies using ethyl acetate. In a one-stage batch experiment, 96.0% of acetic acid could be extracted for the solvent when the ratio of organic-to-aqueous phases is 4:1. For simulation results, they were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.1035-1040
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• 2012

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been found to be effective treatment of Parkinson's disease (PD). This study aims to evaluate the effect of DBS for rigidity during DBS surgery. Six Parkinsonian patients who received STN-DBS surgery participated in this study. The examiner imposed flexion and extension of a patient's wrist randomly. Resistance to passive movement was quantified by viscoelastic properties (two damping constants for each of flexion and extension phase and one spring constant throughout both phases). All Viscoelastic constants decreased by DBS (p<0.01). Specifically, reduction in damping constant during flexion ($B_f$) was greater than those of damping constant during extension ($B_e$) and of spring constant (p<0.05). $B_f$ would be appropriate for evaluation of effect of DBS for rigidity during DBS surgery.

• Elastomers and Composites
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• v.54 no.1
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• pp.14-21
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• 2019

Main-chain/side-chain liquid crystalline polymers (MCSCLCPs) combined with an azobenzene group and a cholesteryl group were synthesized to impart light and temperature sensitivity to the polymer. The polymers were designed with the azobenzene unit as the mesogenic group of the main-chain and various compositions of the azobenzene and cholesteryl units as the mesogenic group of the side-chain. The chemical structures and physical properties of the synthesized polymers were investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, and ultraviolet-visible (UV-Vis) spectroscopy. All the MCSCLCPs were amorphous and exhibited enantiotropic liquid crystal phases; these polymers achieved the nematic phase with increasing content of the azobenzene group and exhibited the cholesteric phase with weak liquid crystallinity as the content of the cholesteryl group was increased. Furthermore, the polymers containing the azobenzene group showed photoisomerization when exposed to UV-Vis light, and the CP-A3C7 and CP-A5C5 polymers exhibited thermochromism in the temperature range of the liquid crystal phase.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.434-438
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• 2018

The sintering behavior of $BaFe_{12}O_{19}$ with the addition of one and three weight % of $CuWO_4$ as a liquid phase sintering aid is studied. Samples are sintered in the temperature range $900-1250^{\circ}C$ and the effect of $CuWO_4$ addition on density, microstructure, phase composition and magnetic properties is examined. Compared to $BaFe_{12}O_{19}$ with no sintering aid addition, addition of 1 wt % $CuWO_4$ retards densification. Addition of 3 wt % $CuWO_4$ promotes densification at lower sintering temperatures but retards densification at temperatures > $1050^{\circ}C$. Three wt % $CuWO_4$ addition induces the formation of $BaWO_4$ and $Ba_3WFe_2O_9$ secondary phases at temperatures ${\geq}1100^{\circ}C$. Addition of $CuWO_4$ causes a decrease in saturation magnetization, remanent magnetization and coercivity.

• Journal of KIBIM
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• v.12 no.3
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• pp.18-29
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• 2022

Recently, research on the application of BIM has continuously been active not only in architecture but also in civil engineering in order to improve work efficiency across the project's planning, design, construction and maintenance phases. However, the empirical applications of BIM targeting to civil engineering scope of construction sites still lags compared to architectural sized projects. This is because BIM tools are mainly based upon vertical structures of architecture, thereby most of them have difficulties and limitations to get utilized on horizontal structures of civil engineering. Therefore, this study intends to propose automation technology of design using BIM library and to indicate its field availability through case application on a railway project representing linear infrastructure. In addition, it put forward the utilization plan of the automation technology upto 4D and 5D by continue making use of the BIM model created in the project's design stage up through the maintenance stage. The novel method of the technology proposed in this paper incorporates the automatic creation of the BIM library based on two-dimensional tunnel cross-sections and sweeping of it over three-dimensional alignment to create a BIM model of linear infrastructure. The proposed technology is anticipated to improve the efficiecny of modeling process of railway projects based on linear structures.

• Journal of Korean Society for Quality Management
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• v.50 no.3
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• pp.425-440
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• 2022

Purpose: The purpose of this paper is to improve the chromaticity coordinate quality of white LED packages for automobiles that require high quality and reliability. Methods: The project follows the structured methodology of the Six Sigma DMAIC Roadmap, which consists of Define, Measure, Analyze, Improve and Control phases. Results: A CTQ is determined based on COPQ analysis, and a process map and a XY matrix are utilized for selecting process input variables. Three vital Few Xs are identified through data analysis; amount to mix at one time, deviation by head pumps, and deviation by production magazines, and process improvements are performed for each of the three vital Few Xs. Conclusion: The improved process conditions for the three vital Few Xs are applied to the production line, and the results show that the percent defective of chromaticity coordinate has improved from 1.59% to 0.63% and a financial effect of about 50 million won per year is obtained.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.696-697
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• 2015

Cost, schedule, and quality are the three major performance indicators for any construction project. Under the globalized competition in the nuclear industry, researchers and practitioners have also explored a systemized and integrated management system for cost, schedule, and quality. In order to address this issue, the concept of earned value management system (EVMS) has been often utilized. However, implementing EVMS for a mega-project of nuclear power plant (NPP) construction requires extensive overhead efforts. Though previous studies proposed structures and methods for effective NPP EVMS, there has been no legitimate study for data collection strategy for practical implementation. In this context, the purpose of this paper is to develop an effective data collection strategy for NPP EVMS. Firstly, the barriers to practical NPP EVMS were identified based on literature review and expert interviews. Strategies for data collection were then developed based on different phases of project life cycle. This study focuses on the 'life-cycle integrated progress management system' for NPP construction from an owner's perspective Therefore, results of this study can be used as a guide for preparing request for proposals (RFP) of an NPP owner organization.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.2
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• pp.145-152
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• 2024

The present study investigated the digital color characteristics corresponding to different maturity stages and maturation levels of white croaker Pennahia argentatus specimens collected from the Southern Sea of South Korea. Maturity stages were determined using photomicrographs depicting ovarian developmental phases and compared with digital color values. The specimens ranged in body length from 21-36 cm, with mature ovaries observed within the 24-30 cm length range. To differentiate the maturing, mature, spawning, and post-spawning stages of the gonads, boundary lines were established based on specific coordinates. For the ovaries, a dividing line was drawn through (-10, -10) and (15, 5), described by the equation Y=3/5X-4; while for the testes, the line passed through (20, 0) and (0, 15), indicated by the equation Y=-3/4X+15. However, the visual determination of the maturity stages proved challenging due to overlapping color values. Consequently, this study underscores the efficacy of employing digital color measurements over subjective visual assessments to evaluate the maturity of white croaker gonads and offers more quantitative insights.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.259-266
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• 2014

This study investigated the effects of water temperature and photoperiod on oxygen consumption (OC) in the giant grouper Epinephelus lanceolatus. OC rate in the giant grouper at 17, 22, 27 and $32^{\circ}C$ were $61.7{\pm}0.4$, $72.2{\pm}0.6$, $102.9{\pm}0.8$ and $141.7{\pm}1.0mg\;O_2/kg/h$, respectively, indicating a linear increase in OC with water temperature. Photoperiod was regulated in accordance with the light (06:00~18:00 h, L) and dark (18:00~06:00 h, D) phases of the diel cycle (12L/12D), with a water temperature of at 17, 22, 27 and $32^{\circ}C$. OC rates during the light and dark phases were $62.7{\pm}0.4$, $62.5{\pm}0.3mg\;O_2/kg/h$, respectively, at $17^{\circ}C$. No significant differences were observed between the light and dark phases (P>0.05). OC raters during the light and dark phases were $74.8{\pm}0.7$, $69.6{\pm}0.6mg\;O_2/kg/h$ at $22^{\circ}C$, $107{\pm}1.2$, $98.0{\pm}0.7mg\;O_2/kg/h$ at $27^{\circ}C$ and $147.6{\pm}1.1$, $135.8{\pm}0.8mg\;O_2/kg/h$ at $32^{\circ}C$, respectively, indicating that OC is higher during daylight than nighttime. Giant grouper is thought to be a diurnal fish species, because the level of oxygen consumption during light period was higher than that during dark period.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.189-198
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• 2007

The reproductive cycle, egg capsules in the egg-mass, first sexual maturity, and sex ratio of the bladder moon, Glossaulax didyma ($R\ddot{o}ding$) were investigated. The gastropods collected from the intertidal zone of Biin Bay, Seocheon, Korea were studied by using histological analysis and morphometric data. The gonadosomatic index (GSI) of females and males began to increase in March and reached maximum in May. Then their values sharply decreased from late in May to August due to spawning. The condition index (CI) began to increase in February and reached maximum in May, then gradually declined in the spawning period. The CI calculated for determination of the spawning period was coincided with changes in the GSI and gonadal phases. Spawning occurred between late in May to August in females and early in May to August in males. Spawning peak was observed between July and August when the seawater temperature rose to 19 $^{\circ}C$. Reproductive cycle with the gonadal development phases of this species can be divided into five successive stages in females and four in males: in females, early active stage (December to February), late active stage (February to March), ripe stage (April recovery stage (August to November); in males, active stage (December to March), ripe stage (March to July), copulation stage (early May to August), and recovery stage (August to January). Fully matured oocytes were approximately 250-270 ${\mu}m$ in size. The egg-mass was a hat in shape, and a number of egg capsules were found in an egg-mass. An egg capsule was 0.53-0.57 mm in size. An embryo (veliger larva) hatched from an egg capsule. Percentage of first sexual maturity in females and males were over 50% for individuals that are 40.1-45.0 mm in shell radius, and 100% for those that are over 45.1 mm. The sex ratio of female to male was significantly different from 1:1 $(x^2\;=\;57.22,\;p\;<\;0.05)$.