• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.334-343
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• 2015

This study was carried out to evaluate quantitatively some properties (density, equilibrium moisture content, shrinkage, water vapor adsorption, water absorptivity, compressive strength, bending strength, hardness and decay resistance) of Larix kaempferi lumber which was heat-treated by hot air and has been used commercially in Korea. Equilibrium moisture content of the heat-treated wood was decreased with increase of hydrophobicity. Dimensional stability of the wood was improved with decrease of shrinkage, water vapor adsorption and free water absorptivity. Also, with the thermo-chemical changes of wood component and lower equilibrium moisture content, decay resistance and compressive strength of heat-treated wood were increased. But, bending strength and hardness of wood were decreased.

• The Korean Journal of Ecology
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• v.24 no.4
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• pp.223-226
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• 2001

The leaf water relations and photosynthetic rate during acute soil drying were compared in potgrown grapevine cultivars, Vitis vinifera cv. Chardonnay and V. vinifera cv. Riesling. Leaf water potential in Riesling decreased significantly from day 2 after water had been withheld, while in Chardonnay leaf water potential for the water-stressed plants was almost identical with that in well watered plants during the first 4 days. Higher stomatal conductance and photosynthetic rate in Chardonnay than Riesling were observed until day 3 after withholding water. Photosynthetic rate in water-stressed Chardonnay was not different from that in control plants until day 3 after withholding water, while that in water-stressed Riesling was reduced markedly from day 2. In Riesling, osmotic potential at turgor loss point was not changed irrespective of watering conditions. However, in Chardonnay osmotic potential at turgor loss point decreased more in the water stressed conditions than in well watered conditions. The osmotic adjustment in Chardonnay under water stress conditions must contribute to the maintenance of higher stomatal conductance and photosynthetic rate than those in Riesling for a significant period of the drying process. Though difference in stomatal conductance between the two cultivars was shown in the process of soil drying, stomatal conductance of both cultivars responded to vapor pressure difference between leaf and ambient air, rather than soil water status and leaf water potential.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.7-10
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• 2002

In this study, polyolefin compounds were developed and evaluated for replacing a jacket material of URD power cables. The characteristics of compounds were investigated by water vapor transmission (WVT) test and mechanical test. In WVT test, all polyolefin compounds showed the superior water resistance to conventional PVC. The molecular structure and density of polyolefin play an important role in WVT. Also, polyolefin compounds showed the suitable characteristics in mechanical test. Especially, polyolefin compounds having linear molecules showed the superior characteristics to LDPE ones. From this study, it can be considered that polyolefin compounds may be suitable to jacket material for URD power cables.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.255-265
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• 2008

This paper presents the optimization process of evaporator for a vapor compression cooling system for high heat flux CPU. The CPU thermal capacity was given by 300W. Evaporating temperature and mass flow rate were $18^{\circ}C$ and 0.00182kg/s respectively. R134a was used as a working fluid. Channel width(CW) and height(CH) were selected as design factors. And thermal resistance, surface temperature of CPU, degree of superheat, and pressure drop were taken as objective responses. Fractional factorial DOE was used in screening phase and RSM(Response Surface Method) was used in optimization phase. As a result, CW of 2.5mm, CH of 2.5mm, and CL of 484mm were taken as an optimum geometry. Surface temperature of CPU and thermal resistance were $33^{\circ}C\;and\;0.0502^{\circ}C/W$ respectively. Thermal resistance of evaporator designed in this study was significantly lower than that of other cooling systems such as water cooling system and thermosyphon system. It was found that the evaporator considered in this work can be a excellent candidate for a high heat flux CPU cooling system.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.484-487
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• 2018

In this paper, the optical and electrical properties of ytterbium films were studied for water vapor transmission rate (WVTR) analysis of encapsulation films used in organic electronic devices. Ytterbium thin films show a wide range of light transmittance (70-10%) and resistivity ($6.0-0.16m{\Omega}{\cdot}cm$) depending on various film thicknesses (20-100 nm). The Yb thin films were oxidized with moisture and its transmittance and resistance changed in real time. As a result, the WVTR of parylene and aluminum nitride (AlN) laminated thin encapsulation film was measured to be $4.3{\times}10^{-3}g/m^2{\cdot}day$ with the 25 nm thick ytterbium thin film.

• Korean Membrane Journal
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• v.6 no.1
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• pp.61-69
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• 2004

Small angle light scattering (SALS) and field emission scanning electron microscope (FE-SEM) have been used to investigate the effects of alcohol on phase separation of chlorinated poly(vinyl chloride) (CPVC)/tetrahydrofuran (THF)/alcohol (9/61/30 wt%) solution during water vapor induced phase separation. A typical scattering pattern of nucleation & growth (NG) was observed for all casting solutions of CPVC/THF/alcohol. In the case of the phase separation of CPVC dope solution containing 30 wt% ethanol or n-propanol, the demixing with NG was observed to be heterogeneous. Meanwhile, the phase separation of CPVC dope solution with 30 wt% n-butanol was found to be predominantly homogeneous NG. Although the different phase separation behavior of NG was observed with types of alcohol additives, the resultant surface morphology had no remarkable differences. That is, even though the NG process by water vapor is either homogeneous or heterogeneous, this difference does not play a main role on the final surface morphology. However, it was estimated from the result of hydraulic flux that the phase separation by homogeneous NG provided the membrane geometry with lower resistance in comparison with that by heterogeneous one.

• Textile Coloration and Finishing
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• v.19 no.1 s.92
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• pp.24-30
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• 2007

Heat storage/release system in textile is a useful tool to increase energy efficiency and enhance comfortable microclimate of clothing. Phase change materials(PCM) are used in regulating storage and release properties of thermal energy. To investigate the temperature regulating ability of fabrics with PCM microcapsule(PCMMc), Nylon fabrics were coated with PCMMc via wet processing and they were characterized by SEM, DSC and infrared thermal analyzer. Also, water moisture transpiration, water penetration resistance, peel strength and washing durability of the fabrics were assessed. The water vapor permeation and water penetration resistance decreased with increasing PCMMc content. In DSC analysis, it can be seen that the microencapsulated fabric showed both exothermic md endothermic phenomena at specific temperature. Peel strength was decreased with increasing PCMMc content.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.528-534
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• 2002

CaO ceramics were prepared by conventional sintering process and their hydration behaviors were evaluated by measuring weight increment on saturated water vapor pressure at ambient temperature. CaCO$_3$ and limestone were used as CaO source materials and $Al_2$O$_3$, MgO and SiO$_2$ were added as sintering agents. $Al_2$O$_3$ was a liquid phase sintering agent to increase densification and grain growth rates, whereas MgO and SiO$_2$, densification and grain growth inhibitors. Regardless of composition, all of the prepared CaO ceramics showed the improved hydration resistance as bulk density increased. Especially, when bulk density was more than 3.0 g/㎤, there was no weight increment after 120 h of hydration. Therefore, to decrease contact area between CaO and water vapor by increasing bulk density with the $Al_2$O$_3$ sintering additive was effective for the improvement of CaO hydration resistance.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.8
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• pp.1095-1106
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• 2013

This study evaluated the wear comfort properties of water-vapor-permeable (WVP) garments using a movable sweating thermal manikin. Manikin tests were performed in a climatic chamber (temperature T=20, $35{\pm}0.5^{\circ}C$ and relative humidity $H=50{\pm}10%$) using seven sportswear outfits (a long sleeve shirts and a long pants) made with seven different WVP fabrics. Physiological responses of wear trials could be correlated with measurement parameters of the thermal manikin experiment; subsequently, a regression model that represented a final comfort sensation could be obtained. The regression model developed in this work is based on thermal manikin measurements; consequently, it provides an independent comfort sensation level in a relatively short time at a low cost while maintaining the reproducibility of results. It translates into more actual choices for sportswear manufacturers and sportswear consumers.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.65-70
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• 1993

The effect of particle size of Al powder, water repellent agent and finishing agent on frost resistance, absorption ratio and structure of micropore was examined to improve the physical properties and durability of ALC. According as the amount added of water repellent agent was increased, frost resistance was improved and absorption ratio was decreased. From one side freezing /thaw test, finishing agent which has a low vapor permeation located the crack at close indoor point of ALC specimen. ALC produced from fine Al powder has a low volume reduction by scalling and a sound appearance after freezing/thawing test and top surface freezing test, The crystal of tobermorite in ALC matrix was converted to calcium carbonate by carbonation which was accelerated with the decreasing of water content. Since the micropore of ALC was filled up by calcium carbonate, void ratio was reduced and crack was detected after complete carbonation.