• Journal of the Korean Magnetic Resonance Society
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• v.18 no.2
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• pp.69-73
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• 2014

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.8-9
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• 2009

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.349-356
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• 2006

At present, the selecting system and analytic estimation criterion on repair materials and methods of the deteriorated RC structures have not yet been set up in domestic. Under these circumstances, deterioration such as shrinkage crack, corrosion of rebar has been often occurred after repair, and this finally results in too frequent repairs. In this study, three types of repair methods were experimentally investigated by the accelerating test in a combined deterioration chamber and long-term field exposure test. Three types of repair methods applied in this study belong to a group of polymer cement mortar, which is commonly used in repair works. According to the results of this study, durability of repair mortar layers and corrosion properties of recovered rebar could be investigated in short period by the accelerating test in a combined deterioration chamber, which can simulate the condition of repeated high-and-low temperature and repeated dry-and-wet environment, spraying chloride solution and emitting $CO_2$ gas. After 36 month long-term filed exposure test in the coastal area, harmful macro-cracks are observed in the polymer cement mortar layer of some repair methods. These crack are considered to result from drying shrinkage of polymer cement mortar. Also, after 36 month exposure, amount of corrosion area and weight loss of rebar are found to be different according to the types of repair methods.

• Archives of Plastic Surgery
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• v.33 no.1
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• pp.1-4
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• 2006

Cryopreserved fibroblast implants represent a major advancement for healing of chronic wounds. Bone marrow stromal cells, which include the mesenchymal stem cells, have a low immunity-assisted rejection and are capable of expanding profoundly in a culture media. Therefore, they have several advantages over fibroblasts in clinical use. The ultimate goal of this study was to compare the wound healing accelerating growth factor secretion of the bone marrow stromal cells with that of the fibroblasts and this pilot study particularly focuses on the growth factor secretion to accelerate wound healing. Bone marrow stromal cells and fibroblasts were isolated from the same patients and grown in culture. At 1, 3, and 5 days post-incubating, secretion of basic fibroblast growth factor(bFGF), vascular endothelial growth factor (VEGF), and transforming growth factor beta(TGF-${\beta}$) were compared. In TGF-${\beta}$ secretion fibroblasts showed 12~21% superior results than bone marrow stromal cells. In contrast, bFGF levels in the bone marrow stromal cells were 47~89% greater than that in fibroblasts. The VEGF levels of the bone marrow stromal cells was 7~12 fold greater than that of the fibroblasts. Our results suggest that the bone marrow stromal cells have great potential for wound healing accelerating growth factor secretion.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.447-454
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• 2003

Chemical and microbial properties of Northern sand lance, Ammodytes personatus, sauce fermented at $15^{\circ}C$ with fermentation accelerating agents, koji, enzyme, and squid viscera, were analyzed. Total creatine content of Northern sand lance sauce with squid viscera increased up to 2 months of ripening and decreased gradually thereafter, while that with koji or enzyme, and control, increased up to 3 months of ripening and then decreased slowly. TBA values of all samples increased sharply during early ripening, followed by slight decrease. Free amino acid content with all agents increased continuously as fermentation progressed. Major free amino acids of Northern sand lance sauce were glutamic acid, alanine, valine, leucine, and lysine. Total viable cell counts with all agents also increased during early ripening and then decreased. Total viable cell count of Northern sand lance sauce with squid viscera was the highest followed that with koji, enzyme, and control. Northern sand land sauce manufactured with koji showed the most acceptable sensory evaluation result, followed by that with squid viscera.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.623-630
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• 2004

In this paper, the hydraulic model tests are conducted for the hydraulic characteristics at channel junctions. The experiments are examined through the variation of approaching angle, discharge in the upstream main channel and the discharge ratio between the main channel and the tributary. The experiments are conducted in the channel model having the length of 450cm, the widths of 40cm and 32cm. Four water tanks and pumps are installed in the experimental channel. The length of stagnation zone is increased by Increasing of approaching angle and the discharge in the upstream channel. The length of stagnation increase with the discharge ratio between the main channel and the tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. However, the variation of the stagnation zone near the channel junctions is little at the same approaching angles and the discharge ratioes between the main channel and tributary. Accelerating zone of the velocity is occurred in the middle of the channel in the small approaching angle. However, the influence zone of the accelerating velocity is increased by increasing the approaching angle.

• Nuclear Engineering and Technology
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• v.36 no.4
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• pp.357-363
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• 2004

A prototype long pulse ion source was developed, and the beam extraction experiments of the ion source were carried out at the Neutral Beam Test Stand (NBTS) of the Korea Superconducting Tokamak Advanced Research (KSTAR). The ion source consists of a magnetic bucket plasma generator, with multi-pole cusp fields, and a set of tetrode accelerators with circular apertures. Design requirements for the ion source were a 120kV/65A deuterium beam and a 300 s pulse length. Arc discharges of the plasma generator were controlled by using the emission-limited mode, in turn controlled by the applied heating voltage of the cathode filaments. Stable and efficient arc plasmas with a maximum arc power of 100 kW were produced using the constant power mode operation of an arc power supply. A maximum ion density of $8.3{\times}10^{11}\;cm^{-3}$ was obtained by using electrostatic probes, and an optimum arc efficiency of 0.46 A/kW was estimated. The accelerating and decelerating voltages were applied repeatedly, using the re-triggering mode operation of the high voltage switches during a beam pulse, when beam disruptions occurred. The decelerating voltage was always applied prior to the accelerating voltage, to suppress effectively the back-streaming electrons produced at the time of an initial beam formation, by the pre-programmed fast-switch control system. A maximum beam power of 0.9 MW (i.e. $70\;kV{\times}12.5\;A$) with hydrogen was measured for a pulse duration of 0.8 s. Optimum beam perveance, deduced from the ratio of the gradient grid current to the total beam current, was $0.7\;{\mu}perv$. Stable beams for a long pulse duration of $5{\sim}10\;s$ were tested at low accelerating voltages.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.172-178
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• 2017

Thermal property is one of the important characteristic in the field of energetic materials. As the energy material is released during decomposition, DSC(Differential Scanning Calorimetry) is frequently used for the thermal analysis. In case of the dynamic DSC measurements, thermal dynamic change like melting is prevented from the thermal property measurements. And due to the predicting kg scale, the conditions of the heat exchange with the environment significantly is changed. In this study, As the method to resolve the problem, we predict the thermal aging property using the AKTS thermokinetic program from DSC measurements which performed isothermal method. Predicting the thermal aging properties from ARC(Accelerating Rate Calorimetry) measurement, we compare two results.

• Journal of Power Electronics
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• v.15 no.4
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• pp.1105-1118
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• 2015

Battery energy storage devices (ESDs) have become more and more commonplace to maintain the stability of islanded power systems. Considering the limitation in inverter capacity and the requirement of flexibility in the ESD, the droop control was implemented in paralleled ESDs for higher capacity and autonomous operation. Under the conventional droop control, state-of-charge (SoC) errors between paralleled ESDs is inevitable in the discharging operation. Thus, some ESDs cease operation earlier than expected. This paper proposes an adaptive accelerating parameter to improve the performance of the SoC error eliminating droop controller under the constraints of a microgrid. The SoC of a battery ESD is employed in the active power droop coefficient, which could eliminate the SoC error during the discharging process. In addition, to expedite the process of SoC error elimination, an adaptive accelerating parameter is dedicated to weaken the adverse effect of the constraints due to the requirement of the system running. Moreover, the stability and feasibility of the proposed control strategy are confirmed by small-signal analysis. The effectiveness of the control scheme is validated by simulation and experiment results.

• Journal of the Korean Chemical Society
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• v.67 no.1
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• pp.19-27
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• 2023

During the past few decades, toxicity science is shifting from observative to predictive science. New approach methodologies (NAMs), including in chemico, in silico, in vitro approach, gain attention to reduce, refine, replace the whole animal toxicity testing. However, actual acceptances of NAMs in regulatory decision-making have been limited due to low confidence. To address the current constraints, Accelerating the Pace of Chemical Risk Assessment (APCRA) initiative conducted several case studies and presented the perspectives of next generation risk assessment (NGRA). In this review, we suggested a concept and perspectives of NGRA through analysis on APCRA case studies.