• 한국가구학회지
• /
• 제15권1호
• /
• pp.9-16
• /
• 2004

Five type boxes manufactured from cement(A), wood panel(B), charcoal-packed wood panel(C), plywood panel(D) and charcoal-packed plywood panel(E) were prepared. Relationship of preservation characteristic of strawberry and relative humidity, and properties of thermal and sound insulations in the boxes were examined. During the experimental duration, relative humidity in the cement box was highest and lowest in the charcoal-packed wood panel box. Weight loss of strawberry was greatest in charcoal-packed wood panel box and very little in cement box. In the boxes with charcoal-packed wood panel box and very little in cement box. In the boxes with charcoal, strawberry was preserved for 10 days without getting mold, but in cement box it was covered with mold in 3 days. The charcoal-packed boxes showed higher thermal insulation property than the cement box. There were no significant differences in the property of sound insulation among the 5 type boxes. Consequently, it is suggested that charcoal-packed wood panels can be used for a better ecomaterial.

• 한국공간구조학회지
• /
• 제23권3호
• /
• pp.4-10
• /
• 2023

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.388-389
• /
• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp's properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.1262-1263
• /
• 2011

Sulfur hexafluoride is the most commly used insulation gas in electrical systems. Gas insulated systems are widely used in the electric power industry for transmission and distribution of electrical energy. When $SF_6$ was first discovered, the potential application was only considered for insulation because of good dielectric properties. But the widespread use of $SF_6$ gas by electric power and other industries has led to increase concentrations of $SF_6$ gas in the atmosphere. This concern as to possible effects on global warming because $SF_6$ is a potent greenhouse gas. That's why firstly we studied uniform and nonuniform field property by mixing $SF_6$ and N2 gas. This paper presents the dielectric strength and insulating property for particle contamination under $SF_6/N_2$ mixtures. Two types of mixed gases(50% $SF_6$_50%$N_2$, 20% $SF_6$_80%$N_2$) were applied. We performed tests for the length and shape of particle. Test gas pressure is from 0.3 to 0.7 Mpa. The study was conducted to develop environment-friendly insulating material for GIS that can reduce $SF_6$ gas and make a design criteria for mixtures.

• 농업과학연구
• /
• 제38권1호
• /
• pp.115-120
• /
• 2011

20% of total energy use to sustain temperature of building inside. In this reasons, researchers effort to improve the thermal insulation capacity with new wall system. Using appropriate materials and consisting new wall system should considered in energy saving design. OSB(Oriented strand board), Larch lining board used to consist wall system. $2{\sim}6$ Larch lining board has tongue & groove shape for preventing moisture. Comparing with gypsum board and green timber lining board as interior sheathing material, temperature difference of Green timber wall system was bigger than temperature difference of gypsum board wall system. This aspects indicate that Green timber wall system was revealed higher thermal insulation property than gypsum board wall system. Gypsum board portion transfer heat easily because temperature difference gradient of gypsum board wall system was smaller than OSB wall system. Total temperature variation shape of G-4-S and G-6-S show similar model but, temperature variation shape in green timber wall portion assume a new aspect. The purpose of this study was that possibility of thermal insulation variation and new composition of wall system identify to improve thermal insulation performance. In the temperature case, this study shows possibility of improving thermal insulation performance. Humidity, sunshine and wind etc. should considered to determine building adiabatic properties.

• Journal of Electrical Engineering and Technology
• /
• 제11권2호
• /
• pp.436-444
• /
• 2016

Oil-paper insulation of valve-side windings in converter transformers withstand electrical stresses combining with AC, DC and strong harmonic components. This paper presents the physical mechanisms and experimental researches on partial discharge (PD) of oil-paper insulation at pulsating DC voltage. Theoretical analysis showed that the phase-resolved distributions of PDs generated from different insulated models varied as the increase of the applied voltages following a certain rule. Four artificial insulation defect models were designed to generate PD signals at pulsating DC voltages. Theoretical statements and experimental results show that the PD pulses first appear at the maximum value of the applied pulsating DC voltage, and the resolved PD phase distribution became wider as the applied voltage increased. The PD phase-resolved distributions generated from the different discharge models are also different in the phase-resolved distributions and development progress. It implies that the theoretical analysis is suitable for interpretation of PD at pulsating DC voltage.

• 한국건축시공학회지
• /
• 제12권3호
• /
• pp.291-298
• /
• 2012

For cold weather concreting, frost damage at early age is generated in the concrete, and problems such as delaying of setting and hardening and lowering of strength manifestation emerge due to the low outside air temperature at the early stage of pouring, making the selection of an effective curing method critically important. Unfortunately, the tent sheet currently used as the curing film for heating insulation at work sites, not only has the problems of inferior permeability and extremely deteriorated airtightness, but a phenomenon of continuous fracturing is also generated along the direction of fabric of the material itself, presenting difficult circumstances for maintaining adequate curing temperature. The aim of this study was to develop an improved bubble sheet type curing film for heating insulation of cold weather concrete by combining mesh-tarpaulin, which has excellent tension properties, with bubble sheet, which offers superior insulation performance. The analysis showed that the improved curing film in which BBS1 is stacked to MT was a suitable replacement for curing films currently in use, as it has better permeability, tension property, and insulation performance than the T type film used at work sites today.

• 한국수소및신에너지학회논문집
• /
• 제23권6호
• /
• pp.612-618
• /
• 2012

In this paper, in order to prevent electric shock of high voltage system of HFCV after crash test, insulation performance measurement methods were studied. Under conditions of in-use, insulation performance tests can be divided into measurement method using the vehicle's own RESS as DC voltage source and measurement method using DC voltage from off-vehicle sources. However, these tests can not be applied after a post-crash because parts of high voltage system cover should be removed, and insulation performance can be influenced during these tests. Therefore, we proposed post-crash insulation performance test methods for preventing electric shock through problem analysis of previous post-crash insulation performance tests. Also, test equipment which can measure voltage absence and total energy was developed. We verified performance of the equipment through experiments with vehicle test.

• 설비공학논문집
• /
• 제25권3호
• /
• pp.119-125
• /
• 2013

IInsulation material is generally used for preventing heat loss from heat transport fluids, and water absorption severely reduces the insulation property. The purpose of this study is to evaluate the amount of water absorption supplied by the pouring method and spraying method, to investigate the effects of water absorption on the thermal conductivity of an insulation material, and modeling the relation between water absorption and thermal conductivity. E-glass, a kind of glass fiber, and HYPERLITE, mainly composed of pearlite, are selected, to compare hygroscopic and insulation properties. E-glass is found to have much higher water absorptivity, compared to HYPERLITE. The thermal conductivity of the water-absorbed E-glass is increased by more than 150%, compared to that of no absorption, while variation of the thermal conductivity of HYPERLITE with water absorption is insignificant. A three-stage model of water absorption for thermal conductivity is developed, and the modeling results are found to be in good agreement with the experimental data.

• 마이크로전자및패키징학회지
• /
• 제12권4호통권37호
• /
• pp.359-363
• /
• 2005

유기 박막트랜지스터 (OTFT)를 제작하기 위하여 게이트 절연막으로서 PVP 계통의 유기막을 갖는 MIM(metal-insulator-metal)구조의 유기 절연층 소자를 제작하였다. 유기 절연층의 형은 ITO/Glass 기판위에 polyvinyl 계열의 PVP(poly-4-vinylphenol)를 용질로, PGMEA (propylene glycol monomethyl ether acetate)를 용매로 사용하여 co-polymer PVP를 제조하였다. 또한 열경화성 수지인 poly(melamine-co-formaldehyde)를 경화제로 사용하여 cross-linked PVP 절연막을 합성하였다. 유기 절연층의 전기적 특성은 co-polymer PVP 소자에 비해 cross-link 방식으로 제조된 소자에서 약 300 pA의 낮은 누설전류와 상대적으로 낮은 잡음전류의 특성을 나타내었다. 또한 cross-linked PVP 절연막에서 보다 양호한 표면형상 (거칠기)이 관찰되었으며 정전용량 값은 약 0.11${\~}$0.18 nF의 값을 나타내었다.