• Journal of the Korean institute of surface engineering
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• v.39 no.6
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• pp.295-301
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• 2006

Hard chrome plating has been used in surface hard coating over 50 years both for applying hard coating and re-building of worn components. Hard chrome plating solution and mist pollute environment with very toxic $Cr^{6+}$(hex-Cr) known as carcinogen which causes lung cancer, High velocity oxy-fuel (HVOF) thermal spray coatings of WC base cermet and Co-alloy powders are the most promising candidates for the replacement of the traditional hard chrome plating. Surface properties, wear, and friction behaviors of micron size Co-alloy (T800) and micron size WC-l2Co (WC-Co) have been studied for the application as hard coatings. The temperature dependence of wear and friction behaviors of T800 and WC-Co have been investigated at the temperature of $25^{\circ}C$ and $538^{\circ}C$ for the application to high speed spindle.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.2
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• pp.80-88
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• 2000

In order to predict thermodynamic performance of refrigeration system, it is required to know the oil concentration of the refrigerant/oil mixture. The current method is to extract the working mixture and then to measure the oil weight. In this study, oil concentration is measured in si.tu way without any extraction of the working fluid. Based on the measurement, a working equation is presented as follows, C=a +b x t +c x $t^2$ +(d + e x t +f x $t^2$) x SG. C is oil concentration, t is temperature($^{\circ}C). SG Is specific gravity of mixture and a~f is coefficients The oil concentration ranges over 0~l2 wt% and the temperature ranges over 20~50$^{\circ}C. The specific gravity and temperature are measured using the on-line densimeter and thermometer. This working equation enables to predict the oil concentration without any extraction of the mixture. This equation can be applied for R-12/Naphthenic oil and R-134a/P0E oil liquid mixtures.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.183-186
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• 2003

In a PEM fuel cell electrode, backing layer has tremendous impact on electrode performance. The backing layer provides structural support for the porous electrode, distributes the reactants to the other layers and acts as a current collector. It has major influence on the water management in a PEM fuel cell. Selection of suitable backing layer material for the fabrication of electrode is thus very important to achieve high performance. In this paper we have compared the performance of PEM fuel cell electrodes fabricated using carbon paper EC-TPI-060T, carbon cloth EC-CCI-060T, (ElectroChem Inc.USA) and Carbon cloth from Textron, USA (CPW 003 grade). Mass transport problem was observed under non-pressurized condition, at high current densities, in the caie of EC-CC1-060T carbon cloth electrode (at $50^{\circ}C$), due to its higher thickness. The performance of carbon paper electrode was higher than EC-CCI-060T carbon cloth electrode. The performance of Textron carbon cloth was comparable to EC-TPI -060T carbon paper.

• Biomedical Science Letters
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• v.17 no.1
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• pp.39-45
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• 2011

In the present study, we investigated whether volatile organic compounds induce inflammatory response in human T lymphocytes by evaluating the alteration of inflammatory cytokines. Volatile organic compounds such as formaldehyde, o-xylene, benzene, and hydroquinone have no cytotoxic effects on Jurkat T cells at a high concentration of 50 ${\mu}M$ for 48 h. IL-2, IL-4, IL-13, TNF-${\alpha}$ and IFN-${\gamma}$ were increased after the treatment with volatile organic compounds, although alteration of cytokines is different among volatile organic compounds. LPS as a positive control increased the secretion of IL-2, IL-4, IL-13, TNF-${\alpha}$ and IFN-${\gamma}$. MCP-1 and CCL17 (thymus and activation-regulated chemokine, TARC) were weakly increased after the treatment with volatile organic compounds but the amount of the increased cytokine was below 20 pg/ml. These results suggest that the measurement of cytokine in Jurkat T cells may be used as a useful method for evaluating the toxicity of volatile organic compounds in immune response.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.4
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• pp.201-207
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• 2001

This paper describes an automated detection algorithm of ST-T episodes using global curvature which can connect the isoelectric level in ECG and can eliminate not only the slope of ST segment, but also difference of the baseline and global curve. This above method of baseline correction is very faster than the classical baseline correction methods. The optimal values of parameters for baseline correction were found as the value having the highest detection rate of ST episode. The features as input of backpropagation Neural Network were extracted from the whole ST segment. The European ST-T database was used as training and test data. Finally, ST elevation, ST depression and normal ST were classified. The average ST episode sensitivity and predictivity were 85.42%, 80.29%, respectively. This result shows the high speed and reliability in ST episode detection. In conclusion, the proposed method showed the possibility in various applications for the Holter system.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.214.1-214.1
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• 2013

Tetra-ethoxysilane (TEOS)은 일반적으로 저온 게이트 산화막의 원료 널리 이용되고 있으나 as-deposited 상태에서는 필수적으로 생성된 높은 계면밀도와 고정전하를 제거하기 위하여 수소계면처리, forming gas annealing 등 후처리 공정을 필수적으로 거처야만 한다. 즉 후처리 공정 없이도 일정수준의 계면밀도와 고정전하를 갖을 수 있는 출발물질이 제안되면 산업적 의미를 갖을 것이다. 본 연구에서는 TEOS를 대체할 수 있는 후보재료로써 Tetra-iso-propoxysilane (T-iso-POS)을 제안하였다. T-iso-POS는 iso 구조의 3차원적 특수 구조를 가지므로 더 쉽게 분해 될 수 있어 탄소의 결합을 억제 할 수 있다고 사료된다. 용량 결합형 PECVD (13.56 MHz) 장비를 이용하여 RCA 세정을 실시 한 p-Si (100) 기판위에 TEOS 혹은 T-iso-POS (2 sccm)와 O2를 도입(50 sccm), 플라즈마 전원(20~100 W), 압력(0.1~0.5 torr), 온도 ($170{\sim}400^{\circ}C$), 전극 간 거리 (1~4.5cm)의 조건 하에서 증착하였다. 얻어진 각각의 SiO2 막에 대해, 성장 속도, 2% BHF 용액보다 에칭 속도, IV 특성과 C-V 특성, FT-IR에 의해 화학구조 평가를 실시했다. T-iso-POS원료로 사용하여 TEOS보다 낮은 약 $200^{\circ}C$에서 증착 된 산화막에서 후 처리 없이도 10 MV/cm 이상의 절연 파괴 특성을 나타내는 우수한 게이트 절연막 제작에 성공했다. 그 성장 속도도 약 20 nm/min로 높았다.

• Korean Journal of Artificial Intelligence
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• v.9 no.2
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• pp.15-21
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• 2021

This paper conducted a feasibility study by applying an Internet of Things and Artificial intelligence-based management system for the elderly living alone in an aging society. The number of single-person families over the age of 50 is expected to increase, and problems such as health, safety, and loneliness may occur due to aging. Therefore, by establishing an IoT-based care system for the elderly living alone, a stable service was developed through securing a rapid response system for the elderly living alone and automatically reporting 119. The participants of the demonstration test were subjects under the jurisdiction of the "Seongnam Senior Complex," and the data collection rate between the IoT sensor and the emergency safety gateway was high. During the demonstration period, as a result of evaluating the satisfaction of the IoT-based care system for the elderly living alone, 90 points were achieved. We are currently in the COVID-19 situation. Therefore, the number of elderly living alone is continuously increasing, and the number of people who cannot benefit from care services will continue to occur. Also, even if the COVID-19 situation is over, the epidemic will happen again. So the care system is essential. The elderly care system developed in this way will provide safety management services based on artificial intelligence-based activity pattern analysis, improving the quality of in-house safety services.

• Child Health Nursing Research
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• v.28 no.1
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• pp.70-81
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• 2022

Purpose: This study aimed to develop and evaluate the effectiveness of an educational program on developmental positioning (EPDP) for nurses in neonatal intensive care units (NICUs). Methods: The study utilized a non-equivalent control group pretest-posttest design. Sixty NICU nurses were recruited from two university hospitals in Daejeon, South Korea. The EPDP consisted of a 7-week program: 3 weeks of education and practice, followed by 4 weeks of encouragement messages using social networking services. Developmental positioning (DP) posters and DP aids were also provided during the intervention period. The intervention group (n=30) received the EPDP, but not the control group. The data were analyzed using the 𝜒² test, the Fisher exact test, the independent t-test, and repeated-measures analysis of variance. Results: Participants' knowledge (t=7.49, p<.001), attitudes (t=1.99, p=.001), self-efficacy (t=2.99, p=.004), performance of DP (t=2.98, p=.004) and Infant Positioning Assessment Tool (IPAT) scores (F=29.50, p<.001) were significantly higher in the intervention group than in the control group. Conclusion: The EPDP can be an effective and useful program for improving the performance of DP among NICU nurses by increasing their knowledge, attitudes, and self-efficacy of DP. However, further research involving various NICU settings is needed to gather more empirical evidence.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.703-710
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• 2006

The objective of this study is to acquire stabilization of collapse of cut-slope in Chang-Nyung, Gyeong-Nam. The following shows the results of this study. We applied a reinforcement method with the latticed beam $(0.50\times0.50)$ + permanent anchor($PC\;6\times\phi12.7mm$, Ta = 50.0t/EA, etc 3.0m), and fill gravels(D=35cm) in the latticed beam. We attenuated the slope (1:2.0), and stabilized the slope pace by ASANA method. We planned a drainage way(U-type, $0.40\times0.40$) in order to prevent surface water from inflowing into underground.

• Journal of the Korean Home Economics Association
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• v.50 no.3
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• pp.35-50
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• 2012

This study aims to investigate the effect of group home adolescents' emotion regulation and school adjustment. A survey was carried out on a total of 246 middle and high school students, who live in group homes. For data analysis, t-test, two-way ANOVA, Pearson's correlation analysis, multiple regression analysis, and reliability coefficients were carried out by using SPSS program(version 18.0). The findings of this study were as follows: First, there were significant differences in emotion regulation ability of group home adolescents, depending on the grade and gender. Second, there was an interaction by grade and gender in school adjustment of group home adolescents. Last, group home adolescents' gender, grade, and emotion regulation ability affected their school adjustment.