• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.296-297
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• 2011

A series of thermogravimetric analysis tests were conducted to predict the lifetime of the PTFE electrical insulation material. The prepared PTFE samples were heated from $25^{\circ}C$ to $700^{\circ}C$ at different heating rates. The kinetic energy of the PTFE was calculated from the logarithmic heating rate versus reciprocal temperature curves at constant conversion levels. Also, the lifetime of the PTFE for a given operating temperature can be predicted using the relationship between the activation energy and the estimated lifetime proposed by Toop.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.111-116
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• 2004

The development of Aphis gossypii was studied at various constant temperatures ranging from 15 to 35$^{\circ}C$, with 60-70％ RH, and photoperiod of 16：8 (L：D h). Mortality of A. gossypii was high in the early developmental stages, and at high temperatures. The total immature developmental period ranged from 4.6 to 11.5 days. The lower developmental threshold temperature and effective cumulated temperature for all immature stages were 5.0$^{\circ}C$ and 106.8 degree-day, respective. The nonlinear shape of temperature-dependent development was well described by the modified Sharpe and DeMichele model. The normalized cumulative frequency distributions of developmental period for each life stage were fitted to the three-parameter Weibull function.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.597-604
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• 2004

This work involves quantitatively investigating the correlation between reductions in strength and variations in pore structure under high temperature that can be utilized as estimation for predicting the inner temperature of member damaged by fire. The experimental results were remarkedly affected by micro-filling effect of silica fume and the different water-binder ratios. The increase of the exposure temperature caused the increase of porosity, which resulted from the reason that evaporable water in gel pore or capillary pores as well as chemically bound water was eliminated from hardened cement paste due to the dehydration of C-S-H and $Ca(OH)_2$. Thermal shrinkage of hardened cement paste gives rise to micro-crack, which cause the increase of porosity. Based on the experimental result that the increase of porosity is in charge of exposure temperature, how porosity is distributed can predict temperature-time history and assess the performance of concrete damaged by fire.

• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.2
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• pp.53-62
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• 2011

The elliptical trainers(ET) can be a good tool for educating engineers by analyzing physical responses in terms of Respiratory Exchange Ratio (RER, epm) and Heart Rate (HR, bpm). For the various energy expenditure, exercise speed, and weight loss both RER and HR are studied in order to study the blood circulations based on the health training cardiorespiratory. As the results, (1) RER increases gradually as the energy expenditure, however, HR increases gradually up to a critical value and then increases rapidly. The critical value of the energy expenditure in our studies was 275 Cal. (2) RER increases gradually as the ET speed increases, however, HR increases gradually up to a critical value and then increases rapidly. The critical value of the ET speed in our studies was about 6.7km/h. (3) RER increases gradually as the weight loss increases (or, the metabolic cost increases), however, HR is almost nothing to do with the increase of the weight loss.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.113-118
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• 2023

This study analyzed the effects of macroeconomic variables, including housing affordability, and bank loan-related variables on variation in housing prices using multiple regression models. As a result of the analysis, consumer price growth rate, the total currency growth rate, and the housing affordability growth rate had a significant positive effect on changes in housing prices. As a result of analyzing the period of rising and falling housing prices, consumer price growth rate and the total currency growth rate during the period of rising housing prices had a significant positive effect on housing prices. Unlike the period of rising housing prices, the growth rate of household loans was found to have a significant positive effect on changes in housing prices. On the other hand, unlike the period of rising housing prices, the growth rater of mortgage loans was found to have a significant negative effect on changes in housing prices. The growth rate of housing affordability index did not have a significant positive effect on changes in housing prices during a falling housing prices. The determinants of housing prices showed different patterns during the period of rising housing prices and falling housing prices.

• Life and Agrochemicals
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• s.257
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• pp.30-33
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• 2010

총 40,162백만$, 명목-8.7% 실질-6.0%로 2년 연속 성장세 돌아서 바스프 다우 1단계씩 상승, 몬산토 2단계 하락, 다른 회사들 동 순위

• Agrochemical news magazine
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• v.25 no.1 s.194
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• pp.22-26
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• 2004

• 주택과사람들
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• s.202
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• pp.104-105
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• 2007

시가 급등, 과표 적용률 상승 등으로 금년엔 종부세 부담이 훨씬 커질 전망이다. 2006년의 종부세는 납부하든 안 하든 정해진 금액이었지만, 금년의 종부세는 지금부터 대비하면 줄일 수도 있다.

• Korea Petroleum Association Journal
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• no.3 s.37
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• pp.89-91
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• 1984

텍사코사의 최근 보고서에 의하면 80년대말에는 세계 원유공급이 줄어들어 90년대에 유가상승률은 일반물가상승률을 1~2% 상회하게 되며, 천연가스 가격은 중질유가격보다 낮아질 것이라고 한다. 다음은 택사코사의 석유수급 및 가격전망 보고서의 요약이다. <역자주>

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.331-332
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• 2016

본 논문에서는 PWM 슬루율을 제한하기 위한 LC 필터 설계를 제안한다. 기존의 연구에서는 PWM 입력전압과 필터링된 출력 전압에 대한 주파수 분석을 통해 출력단에 나타나는 슬루율을 제한하였다. 하지만 이러한 분석은 순시 출력 슬루율을 정량적으로 분석하기 어렵다. 본 논문에서는 LC필터의 출력 슬루율을 시간 영역에서 분석하고, 이를 제한하는 LC 필터의 정량적인 설계법을 제시한다.