• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.81-83
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• 2005

The Plant Signaling Network Research Center (SigNet) is a government-funded (by Korea's Ministry of Science and Technology (MOST)/ Korea Science and Engineering Foundation (KOSEF)) research center established at the School of Life Sciences and Biotechnology of Korea University in 2003. The SigNet conducts plant biological studies, especially in the field of developmental and defense biology. The research purpose of SigNet is dissection and analysis of plant development and defense signaling network through multiscientific approaches. Knowledge acquired from SigNet research scientists will provide new integrated view of understanding and potential application of plant development and defense mechanism. The other important mission of the SigNet is nurturing Center of Excellence for future outstanding research scientists of Korea. The SigNet will continue to expend every effort to achieve the goals for the future. Through passionate research endeavor of each laboratory and partnerships within inside and outside laboratories, we will continue to develop world-leading plant research group and to educate new generations of innovative researchers. As the SigNet looks toward the future, the SigNet will try to achieve its mission of research, education and service to the community. And the defense response research of our lab will be presented at later part.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.143-147
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• 2017

Structural studies on the addition characteristics of Nb ions to $BaTiO_3$ solid solutions were performed by XRD and SEM/EDS technique. The X-ray diffraction peaks of the (111), (200) and (002) planes of Nb-doped $BaTiO_3$ solid solutions with different mole% of Nb were analyzed. We also investigated the relationship between the dielectric and structural properties of Nb-doped $BaTiO_3$. The transition temperatures of $BaTiO_3$ solid solution doped with 0.5mole%Nb and 1.0 mole%Nb were ${\sim}116^{\circ}C$ and ${\sim}87^{\circ}C$, respectively, which were found to be shifted to very low temperature from the transition temperature of pure $BaTiO_3$ (about $125^{\circ}C$). As a result of analysis of 1/K versus T and ln[$(1/K)-(1/K_m)$ versus ($T-T_m$)] of the two compositions used in this experiment, the diffusivity slightly differs from that of pure $BaTiO_3$ at temperatures above Curie temperature. And this characteristic was analyzed by applying the modified Curie-Weiss law.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.224-227
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• 2015

Ferroelectric $Pb_2(Sc,Nb)O_6$ were prepared under two different sintering conditions using the oxide mixing method and the electrical properties were measured. The sintering conditions were $1350^{\circ}C$ for 25 minutes and $1400^{\circ}C$ for 20 minutes. EDX spectroscopy and XRD were used to determine the crystalline characteristic of the $Pb_2(Sc,Nb)O_6$ compositions Pyrochlore phase showed about 2% in all $Pb_2(Sc,Nb)O_6$ specimens. It expands the growth of crystals in samples sintered at $1400^{\circ}C$ than $1350^{\circ}C$, but all samples were the optimal crystallization. The temperature and frequency dependence of the complex dielectric constant and admittance were measured to analyze the electrical properties. The high dielectric constant of the specimens reflects the good stoichiometry and crystallization. The maximum value of the dielectric constant in the two specimens treated with sintering at $1350^{\circ}C$ and $1400^{\circ}C$ were more than 27,000, and the dielectric loss at room temperature is smaller than 0.05. The maximum dielectric constant decreased with increasing frequency, the transition temperature also increased in $Pb_2(Sc,Nb)O_6$ compositions. The admittance and susceptance values reach a peak at all temperatures, and the magnitude of the peak increases with increasing measuring temperature. Strong frequency dependent of maximum admittance, susceptance, dielectric constant and dielectric loss were observed.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.287-293
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• 2015

This paper discusses quantitative analyses of patents published for cathode active materials for lithium secondary batteries based on layer structure. Numbers of the patents analyzed were 356, 1628, 2915, 439, and 611 for Korea, USA, Japan, Europe, and PCT (WO), respectively. Trends of improved technologies and alternative technologies concerning lithium cobalt, from 1991 to 2012 were examined and the patent shares distribution of each principal countries about lithium secondary battery technologies were also scrutinized. The number of patents for the mixed structure technology and next-generation lithium secondary battery technology increased numerously in 2000. Particularly in 2005, lots of patents were also published and SANYO (34.5%), SONY (17.5%), LG (7%), and SAMSUNG (5.5%) possessed leading patent applicants. Finally, the research focus on cathode active materials for lithium secondary batteries was confirmed by bubble chart distributions for component-by-step process.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.294-305
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• 2015

We have quantitatively analyzed 1,294 effective patents on "Quantitative Analysis of Patents Concerning Cathode Active Materials for Lithium-Ion Secondary Batteries Based on Layer Structure" from Korea, USA, Japan, Europe and PCT (WO). The importance of technological and patent values of the aforesaid patents were evaluated by the factors shown in Table 1, and 104 major and 20 core patents were selected in compliance with the evaluation from the patents. The technological flow chart over time regarding the selected major and core patents was prepared, and the applying time and development process of patents, as well as the position of core patents were established on the time scale investigated. Finally, the differentiation plans and patent avoidance strategies for the next technology development, in comparison with the technologies of patents already applied and registered, were suggested.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1095-1101
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• 2020

Vessels or aircraft should be loaded with containers or cargo to maintain weight balance in order to be stable when navigating the route. The container loading algorithm is known as the NP problem and several heuristic methods have been studied. Containers can be characterized by the uniform volume and weight, which makes it easier to find an optimal loading method. In this paper, we propose an algorithm for weight balance when the volume and weight of an object are uniform. It is assumed that the loading space has a special structure of m * n mesh (where m and n are both odd). In this case, we designed a greedy algorithm and proved that the algorithm is optimal in that it can always find a loading position that maintains a weight balance regardless of the number of objects. Our algorithm can be used in many engineering problems, such as loading algorithms and load balancing problems.

• Korean Journal of Materials Research
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• v.32 no.5
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• pp.243-248
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• 2022

This study demonstrates a different approach method to fabricate antimony selenide (Sb₂Se₃) thin-films for the solar cell applications. As-deposited Sb₂Se₃ thin-films are fabricated via electrodeposition route and, subsequently, annealed in the temperature range of 230 ~ 310℃. Cyclic voltammetry is performed to investigate the electrochemical behavior of the Sb and Se ions. The deposition potential of the Sb₂Se₃ thin films is determined to be -0.6 V vs. Ag/AgCl (in 1 M KCl), where the stoichiometric composition of Sb₂Se₃ appeared. It is found that the crystal orientations of Sb₂Se₃ thin-films are largely dependent on the annealing temperature. At an annealing temperature of 250 ℃, the Sb₂Se₃ thin-film grew most along the c-axis [(211) and/or (221)] direction, which resulted in the smooth movement of carriers, thereby increasing the carrier collection probability. Therefore, the solar cell using Sb₂Se₃ thin-film annealed at 250 ℃ exhibited significant enhancement in J_SC of 10.03 mA/cm² and a highest conversion efficiency of 0.821 % because of the preferred orientation of the Sb₂Se₃ thin film.

• Steel and Composite Structures
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• v.49 no.4
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• pp.381-392
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• 2023

This study experimentally investigates the flexural behavior of steel-UHPC composite slabs composed of an innovative negative Poisson's ratio (NPR) steel plate and Ultra High Performance Concrete (UHPC) slab connected via demountable high-strength bolt shear connectors. Eight demountable composite slab specimens were fabricated and tested under traditional four-point bending method. The effects of loading histories (positive and negative bending moment), types of steel plate (NPR steel plate and Q355 steel plate) and spacings of high-strength bolts (150 mm, 200 mm and 250 mm) on the flexural behavior of demountable composite slab, including failure mode, load-deflection curve, interface relative slip, crack width and sectional strain distribution, were evaluated. The results revealed that under positive bending moment, the failure mode of composite slabs employing NPR steel plate was distinct from that with Q355 steel plate, which exhibited that part of high-strength bolts was cut off, part of pre-embedded padded extension nuts was pulled out, and UHPC collapsed due to instantaneous instability and etc. Besides, under the same spacing of high-strength bolts, NPR steel plate availably delayed and restrained the relative slip between steel plate and UHPC plate, thus significantly enhanced the cooperative deformation capacity, flexural stiffness and load capacity for composite slabs further. While under negative bending moment, NPR steel plate effectively improved the flexural capacity and deformation characteristics of composite slabs, but it has no obvious effect on the initial flexural stiffness of composite slabs. Meanwhile, the excellent crack-width control ability for UHPC endowed composite members with better durability. Furthermore, according to the sectional strain distribution analysis, due to the negative Poisson's ratio effect and high yield strength of NPR steel plate, the tensile strain between NPR steel plate and UHPC layer held strain compatibility during the whole loading process, and the magnitude of upward movement for sectional plastic neutral axis could be ignored with the increase of positive bending moment.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.9-16
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• 2013

Objective: The aim of this study is to investigate a trend of human error types observed in a series of verification and validation experiments for an Advanced Control Room(ACR) equipped with Lager Display Panel(LDP), Work Station Flat Panel Display(WS FPD), list type Alarm System(AS), Soft Control(SC) and Computerized Procedure System(CPS). Background: Operator behaviors in a fully computerized control room are quite different from those in a traditional hard-wired control room. Operators in an ACR all together monitor plant status and variables through their own interface system such as LDP and WS FPD, are notified of abnormal plant status through their own list type AS, control the plant through their own SC, and follow the structured procedure through their own CPS whereas operators in a traditional control room only separately do their duty directed by their supervisor. Especially the secondary task such as manipulating the user interface of ACR can be an extra burden to all the operators including the supervisor. Method: The Reason's human error classification method was applied to operators' behavioral data collected from a series of verification and validation experiments where operators showed their plant operational behaviors under a couple of harsh scenarios using the ACR simulator. Results: As operators accustomed to the new ACR system, knowledge or rule based mistakes appearing frequently in the early series of experiments decreased drastically in the latest stage of the series. Slip and lapse types of errors were observed throughout the series of experiments. Conclusion: Education and training can be one of the most important factors for the operators accustomed to the traditional control room to be adapted to the new system and to run the ACR successfully. Application: The results of this study implied that knowledge or rule based mistakes can be reduced by training and education but that lapse type errors might be reduced only through innovative improvement in human-system interface design or teamwork culture design including a new leadership style suitable for ACR.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.142-149
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• 2012

The reduction characteristics of $NO_2$ to NO are experimentally studied over a platinum-based catalyst, especially at lower temperatures below about $200^{\circ}C$. In the present work, two types of steady-state experiments, engine bench and synthetic gas bench tests, are carried out in sequence. Steady-state engine bench tests with the DOC mounted on a light duty 4-cylinder 2.0 liter turbocharged diesel engine are performed and prove that CO plays a major role in $NO_2$ abatement at temperatures below the light-off temperature of CO oxidation, about $200^{\circ}C$. Synthetic gas bench tests are then performed using synthetic gas mixtures with CO, $C_3H_6$, NO, $NO_2$, $O_2$, $H_2O$ and $N_2$ in the $140{\sim}450^{\circ}C$ T-range and show that both CO and $C_3H_6$ are capable of reducing $NO_2$. It is noted that the reaction rate of $NO_2$ with $C_3H_6$ is much higher than that with CO. At temperatures below about $200^{\circ}C$, the reduction of $NO_2$ to NO is promoted with increasing CO concentration and $NO_2$/$NO_X$ ratio and with decreasing $O_2$ concentration, as well as with the presence of $H_2O$.