• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3686-3690
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• 2012

Photochemical degradation of dimethyl phthalate (DMP) in Fe(III)/tartrate/$H_2O_2$ system was investigated utilizing fluorescent lamps as the primary light source. Effects of initial pH, light source, and initial concentration of each reactant on DMP photodegradation was examined. The results show that the system was able to effectively photodegrade DMP utilizing visible light. Fluorescent lamp, halide lamp, UV lamp and sunlight could all be used as the light sources. The optimal pH ranged among 3.0-4.0 for the system. Increases of the initial concentrations of Fe(III) and $H_2O_2$ accelerated the photodegradation of DMP, whereas excessively high initial tartrate concentration resulted in the decrease of photodegradation efficiency and rate of DMP.

• Proceedings of the ESK Conference
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• 1996.04a
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• pp.151-151
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• 1996

컴퓨터 기술의 급격한 발전은 현실세계의 각종 현장을 컴퓨터 가상공간 내에서 시험할 수 있도록 하고 있다. 최근들어급격한 발전이 이루어지고 있는 가상현실(Virtual Reality) 기술과 인간의 감성을 중시한 감성공학적 접근방법 론의 활용은 그 적용범위가 점차 확대되어 가고 있는 상황으로, 제조기업에서 사용되고 있는 통합생산 정보시스템 (Computer Integrated Manufacturing)과의 접목으로 가상공장(Virtual Factory) 시스템을 구현할 수가 있다. 가상공장시스 템은 제조기업의 Businiss를 Design & Engineering, Production Planning & Control, Manufacturing의 3가지 프로세스로 분류한다. 그리고 각 프로세스별로 현재의 CIM시스템에 대한 하부시스템을 검토하고, 인간 중심의 가상기업시스템을 구현 하는데 보완이 되어야 할 사항과 이에 대한 해결 대안으로 Design & Engineering Process에서는 Virtual Engineering(VE) Sub-system, Manufacturing Process에서는 Virtual Manufacturing(VM) Sub-system으로 분류하여 각 Sub-system별 구성모듈을 설계하고 상호간의 Interface 사항을 설계하므로서 가상공장시스템 구현을 위한 기본 요구사항과 조건을 제시하고자 한다.

• Journal of ILASS-Korea
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• v.27 no.4
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• pp.211-218
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• 2022

Recent vehicle regulations have become increasingly stringent in order to reduce greenhouse gases. Then not only movement to replace internal combustion engine vehicles with hybrid vehicles, but also studies of replacing internal combustion engine fuels with low-pollution fuels are increasing. In this study, the characteristics of a vehicle with LPG fuel engine and mild hybrid system is investigated. To avoid shortage of maximum power on LPG engine, a direct injection system of LPG is applied. In addition, P0 mild hybrid system is adopted to enhence the efficiency of the vehicle. The vehicle model is developed in order to predict fuel economy and CO2 emission of LPDi MHEV.

• Progress in Superconductivity and Cryogenics
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• v.12 no.1
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• pp.52-55
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• 2010

A sub-cooled liquid nitrogen system is known as a promising method to develop high voltage superconducting apparatuses such as superconducting fault current limiters (SFCLs) and superconducting cables. To develop a high voltage superconducting machine adopting the sub-cooled liquid nitrogen system with a constant pressure. injecting a non-condensable gas is indispensable. In this study. the dielectric characteristics of insulation gases are investigated and analyzed by using electric utilization factors ($\xi$). It is found that the maximum electric field at sparkover that occurs with 50 % probability. $E_{MAX.50%}$ exponentially decreases as the S increases. This means that the $E_{MAX.50%}$ at sparkover can be estimated with the $E_{MAX.50%}$

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.660-664
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• 2023

In this study, a new system to determine the concentration of cholesterol using a color change was developed. The system comprised diacetylene vesicles and cholesterol oxidase (ChOx). 10,12-Pentacosadiynoic acid (PCDA) was used as the diacetylene compound, and PCDA vesicles were formed using sonication. The H₂O₂ produced during the reaction between cholesterol and ChOx was used to initiate the polymerization of the PCDA in the vesicles. During polymerization, the vesicles changed from colorless to blue. Therefore, the cholesterol concentration was proportional to the intensity of the blue color. The absorption at 665 nm indicated that the blue color was directly proportional to the cholesterol concentration. This indicates that the system can be used for cholesterol detection. The minimum cholesterol concentration detected using this system was 1.0 mM.

• Journal of Radiation Protection and Research
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• v.46 no.3
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• pp.112-119
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• 2021

Background: This work aims to develop a new imaging system based on a pulse shape discrimination-capable Cs₂LiYCl₆:Ce (CLYC) scintillation detector combined with the rotational modulation collimator (RMC) technique for dual-particle imaging. Materials and Methods: In this study, a CLYC-based RMC system was designed based on Monte Carlo simulations, and a prototype was fabricated. Therein, a rotation control system was developed to rotate the RMC unit precisely, and a graphical user interface-based software was also developed to operate the data acquisition with RMC rotation. The RMC system was developed to allow combining various types of collimator masks and detectors interchangeably, making the imaging system more versatile for various applications and conditions. Results and Discussion: Operational performance of the fabricated system was studied by checking the accuracy and precision of the collimator rotation and obtaining modulation patterns from a gamma-ray source repeatedly. Conclusion: The prototype RMC system showed reliability in its mechanical properties and reproducibility in the acquisition of modulation patterns, and it will be further investigated for its dual-particle imaging capability with various complex radioactive source conditions.

• Current Optics and Photonics
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• v.6 no.6
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• pp.608-618
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• 2022

By analyzing the signal-to-noise ratio (SNR) theory of the conventional true color night vision system, we found that the output image SNR is limited by the wavelength range of the system response λ₁ and λ₂. Therefore, we built a double-channel four-band true color night vision system to expand the system response to improve the output image SNR. In the meantime, we proposed an image fusion method based on principal component analysis (PCA) and nonsubsampled shearlet transform (NSST) to obtain the true color night vision images. Through experiments, a method based on edge extraction of the targets and spatial dimension decorrelation was proposed to calculate the SNR of the obtained images and we calculated the correlation coefficient (CC) between the edge graphs of obtained and reference images. The results showed that the SNR of the images of four scenes obtained by our system were 125.0%, 145.8%, 86.0% and 51.8% higher, respectively, than that of the conventional tri-band system and CC was also higher, which demonstrated that our system can get true color images with better quality.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.429-433
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• 2015

The binding ability and hydrogen storage capacity of nitrogen doped carbon nanotube with divacancy (4NDCN_xNT) that is decorated with transition metals was investigated based on density functional theory calculations. Results indicate that scandium shows an ideal reversible hydrogen binding capability with promising system-weight efficiency compared with other transition metals when functionalized with 4ND-CN_xNT. The (Sc/4ND)₁₀-CN_xNT can store up to 50H₂ molecules, corresponding to a maximum gravimetric density of 5.8 wt%. Detailed structural stability and electronic properties were reported as hydrogen molecules were absorbed. It takes about 0.16 eV/H₂ to add one H₂ molecule, which assures reversible storage of H₂ molecules under ambient conditions.

• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.579-581
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• 2010

Solid silica supported ferric chloride ($SiO_2-FeCl_3$) catalyzed one-step synthesis of various benzimidazoles from o-phenylenediamine and aldehydes using $H_2O_2$ as the oxidant. The salient features of this method are simple and convenient procedure, easy purification and shorter reaction times.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.3
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• pp.112-115
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• 2021

Herein, a correlation between B-site cation order and spin-phonon coupling in La₂NiMnO₆ double perovskite has been investigated. Raman spectra of La₂NiMnO₆ double perovskite annealed at 950 and 1400℃ have been measured in the 140-598 K range. A substantial softening of the phonon modes has been observed below the Curie temperature, which emphasized the presence of the spin-phonon coupling in the system. The spin-phonon coupling was found to be stronger in relatively more ordered La₂NiMnO₆ double perovskite. Thus, the magnitude of spin-phonon coupling was influenced by the Ni/Mn cation order.