• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.57-58
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• 2016

리튬이온 배터리는 다른 배터리들에 비해서 높은 전압과 큰 용량을 갖고 있지만 EV와 ESS에 사용되기 위해서는 아직도 다수의 배터리를 직, 병렬로 연결하여 팩으로 구성하여 사용할 필요가 있다. 이 때 팩을 구성하는 리튬이온 배터리들이 셀 스크리닝 기법을 통해서 분류가 된 배터리라고 하여도 표면적인 원인과 직렬조합 배터리팩의 구조에 따라서 온도편차가 발생 할 수 있다. 이 때 이 배터리 팩을 사용하는 시스템의 BMS가 위의 상황을 고려하지 않는다면 BMS의 SOC 추정 값을 신뢰 할 수 없을 것이다. 본 논문에서는 실험결과를 토대로 구조가 다른 배터리 팩을 기존의 BMS로 각각의 SOC를 추정해 보고 배터리 직렬조합 구조에 의한 배터리 팩의 표면온도를 비교 분석해 보려한다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.340-341
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• 2020

본 논문에서는 셀 단위 바나듐 배터리의 220회의 충·방전 사이클 기반으로 획득한 데이터를 통해 장기간 사이클 시험에 따른 바나듐 배터리의 전기적 등가회로 모델에 적용되는 파라미터 분석 결과를 제시한다. 또한 온도에 따른 영향성 분석을 위해 상온(25℃), 저온(15℃) 및 고온(35℃)에서 각 10회 충·방전 사이클 실험을 진행하였고, 이에 대한 파라미터 분석 결과도 제시한다. 장시간 사이클 실험에 따른 전기적 특성분석 결과 바나듐 배터리의 핵심 노화인자는 배터리 전기적 모델에서 직렬저항인 Ri 파라미터임을 시험 검증하였다.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.405-410
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• 2010

The photovoltaic performance of DSSCs fabricated with different electrode thickness and different annealing temperature with the P25 $TiO_2$ and the Dyesol $TiO_2$ was measured. Thickness change of $TiO_2$ electrodes was measured using cross-sectional FE-SEM before and after annealing. Photovoltaic efficiencies of DSSCs were also measured by changing annealing temperature of platinum (Pt) paste on the counter electrode. Photovoltaic performances of DSSCs made with one layer of P25 (${\sim}20.4\;{\mu}m$) and one layer of Dyesol $TiO_2$ (${\sim}9.1\;{\mu}m$) annealed at $500^{\circ}C$ for 30 min. showed highest efficiencies of 3.8% and 5.8%, respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.172-177
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• 2014

We present on a threshold switching device based on AsGeTeSi material which is significantly improved by two $N_2$ processes: reactive $N_2$ during deposition, and $N_2$ plasma hardening. The introduction of N2 in the two-step processing enables a stackable and thermally stable device structure, is allowing integration of switch and memory devices for application in nano scale array circuits. Despite of its good threshold switching characteristics, AsTeGeSi-based switches have had key issues with reliability at a high temperature to apply resistive memory. This is usually due to a change in a Te concentration. However, our chalconitride switches(AsTeGeSiN) show high temperature stability as well as high current density over $1.1{\times}10^7A/cm^2$ at $30{\times}30(nm^2)$ celll. A cycling performance of the switch was over $10^8$ times. In addition, we demonstrated a memory cell consisted of 1 switch-1 resistor (1S-1R) stack structure using a TaOx resistance memory with the AsTeGeSiN select device.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.971-975
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• 2013

In general, the solar photovoltaic power increases with higher solar insolation. However, the solar cell generation efficiency reduces because the solar cell surface is heated by solar insolation. According to advanced research, with a $1^{\circ}C$ increase in the solar cell surface temperature, the generation efficiency decreases by ~0.5%. To solve this problem, we conducted experiments in which we attempted to reduce the solar cell surface temperature using a water jet spray. In this study, we found the long-term experimental results of increases in solar power generation. The experimental results show a comparison of the site with and without cooling and cleaning equipment being installed. The results of the long-term experiments show that solar photovoltaic power generation is increased by at least 13% up to 19% with cooling and cleaning.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.197-200
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• 2008

본 연구에서는 Ketjen black을 이용한 DSCs (Dye-sensitized solar cells)용 다공질의 $TiO_2$ nano-powder 제작기술을 제안한다. $TiO_2$ powder는 sol-gel연소법에 의해 Ti-isopropoxide와 2-propanol을 사용하여 제작되었으며, Ketjen black의 함량($0g{\sim}2g$)을 달리하여 제작된 $TiO_2$ nano-powder의 다공성과 입자의 크기 결정성등의 특성을 고찰하였다. 또한 이러한 $TiO_2$ powder를 paste로 만들어 다른 열처리 온도($100^{\circ}C{\sim}600^{\circ}C$)에서 $TiO_2$ 박막을 이용한 DSCs를 제작한 후 그 효율을 측정하였다. 그 결과 Ketjen black 1g을 함유시켜 만들어진 $TiO_2$ powder의 다공성과 입자 크기가 가장 우수한 것으로 FE-SEM의 측정결과 나타났으며 또한 이 때의 $TiO_2$ powder는 FT-IR의 측정 결과, Ti-O-Ti의 결합구조를 가진 성분과 $H_2O$ 성분으로 구성되어 있음을 알 수 있었다. 그리고 여러 온도에서 제작된 DSCs 실험 셀 중 $500^{\circ}C$의 열처리 공정을 거적 제작된 셀의 효율이 가장 높은 효율이 5.46%를 나타내고 있음을 확인할 수 있었다.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.53-63
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• 1998

The Cd1-xZnxS thin films were grown on the Si(100) wafers by a hot wall epitaxy method (HWE). the source and substrate temperature are 600℃ and 440℃, respectively. The crystalline structure of epilayers was investigated by double crystal X-ray diffraction (DCXD). Hall effect on the sample was measured by the van der Pauw method and the carrier density and mobility dependence of Hall characteristics on temperature was also studied. In order to explore the applicability as a photoconductive cell, we measured the sensitivity (γ), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that the best photoconductive characteristic were observed in the Cd0.53Zn0.47S samples annealed in Cu vapor comparing with in Cd, Se, air and vacuum vapour. Then we obtained the sensitivity of 0.99, the value of pc/dc of 1.65 × 107, the MAPD of 338mW, and the rise and decay time of 9.7 ms and 9.3 ms, respectively.

• New Physics: Sae Mulli
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• v.69 no.10
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• pp.1107-1114
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• 2019

Producing extremely stable high temperature and pressure condition is crucial in order to synthesize novel materials with various functions and to investigate their static and dynamic properties. Already a high pressure in the Mbar range, which is necessary to make novel materials, can be acquired by using a Diamond Anvil Cell (DAC), In this study, a laser-heating system combined with the DAC was designed and installed using two 1064-nm, 100-W fiber lasers on different sides of the DAC to heat the sample and three spectrometers to measure the temperature, pressure, and Raman spectra. A stainless-steel gasket, which is generally used as a sample chamber in high-pressure experiments, was heated to make a thermal radiation source, and the temperature of the heated gasket was obtained by measuring the spectrum of the radiation. By applying this technique, we were able to make various materials and to investigate their physical properties under extreme conditions.

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.25-32
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• 2012

The application of electrical resistivity, which is related to charge mobility, has increased in the field of geotechnical engineering for the detection of underground cavern, faults and subsurface pollution level. The purpose of this study is to investigate the variation of electrical resistivity due to temperature change. Sand-silt mixture specimens prepared in the square freezing nylon cell are frozen in the frozen chamber. Four electrodes are attached on the four side walls of the freezing cell for the measurement of electrical resistance during temperature change. Electrical resistances of sand-silt mixtures with different degrees of saturation (0%, 2.5%, 5%, 10%, 20%, 40%, 60% and 100%) are measured as the temperature of specimens decrease from $20^{\circ}C$ to $-10^{\circ}C$. The electrical resistances determined by Ohm's law are transformed into the electrical resistivity by calibration. Experimental results show that the higher degree of saturation, the lower electrical resistivity at $20^{\circ}C$. Electrical resistivity gradually increases as the temperature decrease from $20^{\circ}C$ to $0^{\circ}C$. For the specimens with the degree of saturation of 15% or higer, electrical resistivity dramatically changes near the temperature of $0^{\circ}C$. In addition, very high electrical resistivity is observed regardless of the degree of saturation if the specimens are frozen. This study provides the fundamental information of electrical resistivity according to the soil freezing and temperature change demonstrates that electrical resistivity be a practical method for frozen soil investigation.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.155-160
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• 2010

The effect of process temperature of a final annealing step in the fabrication of phase change memory (PCM) devices was investigated. Discrete PCM devices employing $Ge_2Sb_2Te_5$ (GST) films as an active element were made in a pore-style configuration, and they were annealed at various temperatures ranging from 160 to $300^{\circ}C$. The behaviors of cell resistance change from SET resistance to RESET resistance were totally different according to the annealing temperatures. There was a critical annealing temperature for the fabrication of normal PCM devices and abnormal operations were observed in some devices annealed at temperatures lower or higher than the critical temperature. Those influences of annealing temperature seem closely related to the thermal stability of a top electrode/GST/heating layer multilayer structure in the PCM devices.