• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.6
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• pp.807-813
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• 1986

Measurements of interface states in a MOS capacitor by DLTS system using wideband monophase lock-in amplifier are discussed. A new signal analysis method that takes into account the bias pulse width and the gate off width is presented to remove the errors in the measured parameters of interface states resulting from the traditional method which neglects the effect of those widths. Theoretical calculations are made for the parameters related to the rate window, signal to noise ratio, and the energy resolution. On the grounds of this discussion, interface states of the MOS capacitor on p-type substrate of (110) orentation are measured with the optimal gate-off width with respect to the S/N ratio and the energy resolution. The results are interface state density of the order of 10**10 (cm-\ulcornereV**-1) to 10**11 (cm-\ulcornereV**-1) in the energy range of Ev+0.15(dV) to Ev+0.5(eV), and constant capture cross section of the order of 10**-16 (cm\ulcorner.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.166-167
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• 2022

The International Energy Agency(IEA) recommends that intergovernmental agreements reduce CO2 emissions by 2050 to about 50% in 2005 in its report. To realize these demands, it is suggested to actively utilize energy efficiency improvement technology, renewable energy, nuclear power, carbon dioxide capture & storage technology (CCS). In the field of building materials and cement, mineral carbonization technology is widely used. Inorganic by-products applicable to greenhouse gas storage include waste concrete, slag, coal ash, and gypsum. If the Mineral Carbonation Act is used, it is expected that about 12 million tons of greenhouse gases can be immobilized every year. Greenhouse gas immobilization using cement hydrate can be immobilized by injecting carbon dioxide into the hydrated products C-S-H, and Ca(OH)2. In the case of immobilization through concrete carbonization, a carbon dioxide promotion test is used, which is often different from the actual carbon dioxide carbonization reaction. If the external carbon dioxide concentration is abnormally higher than the reality, it is thought that it will be different from the actual reaction. In this study, the carbonation phenomenon according to the concentration and identification of the carbon dioxide reaction mechanism of cement hydrate was to be considered.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.3
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• pp.267-273
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• 2023

As the impacts of global climate change become increasingly apparent, the reduction of carbon emissions has emerged as a critical subject of discussion. Nuclear power has garnered attention as a potential carbon-free energy source; however, the rapidity of load following in nuclear power generation poses challenges in comparison to fossil-fueled methods. Consequently, power-to-gas systems, which integrate nuclear power and hydrogen, have attracted growing interest. This study presents a preliminary design of a very high temperature reactor (VHTR) integrated blue hydrogen production process utilizing DWSIM, an open-source process simulator. The blue hydrogen production process is estimated to supply the necessary calorific value for carbon capture through tail gas combustion heat. Moreover, a thermodynamic assessment of the main recuperator is performed as a function of the helium flow rate from the VHTR system to the blue hydrogen production system.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.629-635
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• 2014

This paper presents annual energy production (AEP) by a 1.5kW wind turbine due to be installed in Deokjeok-Do island. Local wind data is determined by geometric shape of Deokjeok-Do island and annual wind data from Korea Institute of Energy Research at three places considered to be installed the wind turbine. Numerical simulation using WindSim is performed to obtain flow pattern for the whole island. The length of each computation grid is 40 m, and k-e turbulence model is imposed. AEP is determined by the power curve of the wind turbine and the local wind data obtained from numerical simulation. To capture the more detailed flow pattern at the specific local region, Urumsil-maul inside the island, fine mesh having the grid length of 10m is evaluated. It is noted that the input data for numerical simulation to the local region is used the wind data obtained by the numerical results for the whole island. From the numerical analysis, it is found that a local AEP at the Urumsil-maul has almost same value of 1.72 MWh regardless the grid resolutions used in the present calculation. It is noted that relatively fine mesh used for local region is effective to understand the flow pattern clearly.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.85-94
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• 2013

Recently, researches of piezoelectric energy harvesting were tried and in this study, a piezoelectric energy harvesting clothes was developed. First, piezoelectric energy harvesting zone on the extremities were drawn by 3D motion capturing and as a result, the hip, the elbow, and the knee were determined. A new structure of piezoelectric harvester was developed for appling to clothes. Because it needed to be flexible and sensitive for human body, the 2 layer stacked structure was proposed. A prototype of seamless garment was designed for a harvesting clothes because it needed to be body-tight and not to restrict the movement. High peak-to-peak voltages were acquired from the energy harvesting clothes.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.343-349
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• 2012

The solar proton telescope (SPT) is considered as one of the scientific instruments to be installed in instruments for the study of space storm (ISSS) which is determined for next generation small satellite-1 (NEXTSat-1). The SPT is the instrument that acquires the information on energetic particles, especially the energy and flux of proton, according to the solar activity in the space radiation environment. We performed the simulation to determine the specification of the SPT using geometry and tracking 4 (GEANT4). The simulation was performed in the range of 0.6-1,000 MeV considering that the proton, which is to be detected, corresponds to the high energy region according to the solar activity in the space radiation environment. By using aluminum as a blocking material and adjusting the energy detection range, we determined total 7 channels (0.6~5, 5~10, 10~20, 20~35, 35~52, 52~72, and >72 MeV) for the energy range of SPT. In the SPT, the proton energy was distinguished using linear energy transfer to compare with or discriminate from relativistic electron for the channels P1-P3 which are the range of less than 20 MeV, and above those channels, the energy was determined on the basis of whether silicon semiconductor detector (SSD) signal can pass or not. To determine the optimal channel, we performed the conceptual design of payload which uses the SSD. The designed SPT will improve the understanding on the capture and decline of solar energetic particles at the radiation belt by measuring the energetic proton.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.561-569
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• 2017

In this study, a synthetic amine made using the ethylene oxide-ammonia reaction was used as an absorbent to remove carbon dioxide. Existing absorbents were used in a mix in order to improve performance; however, because the ethylene oxide-ammonia reaction generates primary, secondary, and tertiary amines simultaneously, it has the merit that separate mixing of the absorbents was not needed. The performance of carbon dioxide absorption with the synthetic amine was compared to that of MEA. As a result of an experiment, it was determined that the $CO_2$ loading was 1.15 times better than that of MEA (a commonly used amine), while the cyclic capacity was 2.28 times higher. Because the heat of reaction was 1.10 times lower than for MEA, the synthetic amine showed superior performance in terms of absorption and regeneration.

• Clean Technology
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• v.20 no.4
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• pp.359-366
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• 2014

Attrition characteristics of PKM1-SU particles, $CO_2$ absorbents for pre-combustion $CO_2$ capture process, and FCC particles, catalytic particles for hydro cracking of crude oil, were investigated at high temperature and high pressure conditions. Particle attrition tests were executed at various kinds of temperature ($0-400^{\circ}C$) and pressure (0-20 bar) conditions in a cylinder type bubbling fluidized bed with 15.1 cm diameter, 120 cm height and 1 mm orifice-sparger tube. Attrited particles before and after tests were analyzed by BET, optical microscopy, and particle size analyzer. Effects of bed material height (solid inventory) and steam injection were also verified by using ASTM D5757-95, conventional attrition test method.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.32-37
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• 2009

Photovoltaic(PV) permits the on-site production of electricity without concern for fuel supply or environmental adverse effects. The electrical power is produced without noise and little depletion of resources. So BIPV(Building-Integrated Photovoltaic) system have been increased around the world. Hereby the relative installation costs of the system will be relatively low compared to traditional installations of PV in high-rise buildings. This paper examined possibility of building integrated balcony PV system and analyzed both performance and problems of this system. The system is influenced by conditions such as irradiation, module temperature, shade and architectural component etc. If this BIPV system of 1.1kW is possible the natural ventilation in the summer case, the temperature of PV module decrease and then the efficiency of PV system increase generally. By the results, the annual averaged PR of BIPV system of cold facade type is about 74.7%.

• Nuclear Engineering and Technology
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• v.50 no.2
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• pp.253-258
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• 2018

A microcell $UO_2$ pellet, as an accident-tolerant fuel pellet, is being developed to enhance the accident tolerance of nuclear fuels under accident conditions as well as the fuel performance under normal operation conditions. Improved capture-ability for highly radioactive and corrosive fission product (Cs and I) is the distinct feature of a ceramic microcell $UO_2$ pellet, and the enhanced pellet thermal conductivity is that of a metallic microcell $UO_2$ pellet. The fuel temperature can be effectively decreased by enhanced thermal conductivity. In this study, the material concepts of metallic and ceramic microcell $UO_2$ pellets were designed, and the fabrication process of microcell $UO_2$ pellets embodying the designed concept was developed. We successfully implemented the microcell $UO_2$ pellets and produced microcell $UO_2$ pellets. In addition, an assessment of the out-of-pile properties of a microcell $UO_2$ pellet was performed, and the in-reactor performance and behavior of the developed microcell pellets were evaluated through a Halden irradiation test. According to the expectations, the excellent performance of the microcell $UO_2$ pellets was confirmed by the online measurement data of the Halden irradiation test.