• 약학회지
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• 제21권2호
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• pp.101-109
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• 1977

The effect of humidity on the aging process of hydrous aluminum oxide prepared by the reaction of aluminum chloride and sodium bicarbonate solution at pH 7.8, which was then kept in various atmosphere under relative humidity at 37.deg. was observed by the measurements of acid consuming capacity, X-ray diffraction and IR absorption. The humidity was one of the important factors influencing the aging process of hydrous aluminum oxide during storage. The higer the humidity, the more was accelerated age, crystalize and loss in acid reactivity. Depending on the humidity, the aging product was different, especially, in the case of up to the relative humidity of 72%, it forming bayerite. On the other hand, the hydrous aluminum oxide aged below the relative humidity of 50% was still amorphous even after 120 days storage. When hydrous aluminum oxide was aged under higher humidity, definite IR absorption bands develop as the hydroxys become part of an ordered structure, and it showed their characteristic absorption band around 1630 and 1060 cm$^{-1}$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.57.1-57.1
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• 2011

The effects of relative humidity on the properties of the porous $ZrO_2$ ceramics were investigated in terms of the curing behavior of phenolic resin as a binder. The $ZrO_2$ powders containing 5wt% of phenolic resin were conditioned in a consistent chamber condition at a temperature of $50^{\circ}C$ and different humidity levels (25, 50, 75, and 95%) for 1 h. The exposure of humid atmosphere caused changes of density and microstructure in the green bodies. The higher level the powders were exposed to the humid atmosphere, the lower green density was obtained and the more irregular microstructure was observed due to aggregation by the curing of phenolic resin. After firing, the porosity of specimens has risen from 35.7% to 38.1% and Young's modulus has declined in response to the variation of green density. These results could be explained by the degree of resin cure which was associated with the area under the exothermic peak enclosed by a baseline of DSC thermogram curve. Also, the curing behavior of phenolic resin according to relative humidity has been confirmed by decrease of ether groups which have interacted with the phenolic-OH group and the hexamine as a curing agent. Consequently, it could be demonstrated that increase the relative humidity during fabrication of porous $ZrO_2$ diminished the compaction and properties of specimens after firing owing to curing of phenolic resin.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.773-777
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• 2002

In this study, we analyzed the LPG and LNG sensitivity measurement and voltage variation using catalytic type gas sensor characteristics in catalytic combustion type gas detecter sensors. gas detector shall operate as intended when exposed for 24 hours to air having a relative humidity of 0~85 percent at a temperature of $20[{\mu}m]$ and humidity of 45 percent at a temperature of $-10{\sim}40[^{\circ}C]$ the gas detecter sensors are to be subjected to operation for 210 days in an area that has been detemined to be equivalent to a typical residential atmosphere with an air velocity of 50 [cm/sec]. The source of energy for a gas detector sensors employing a supplementary basic circuit is energized from a separate source of supply direct applied voltage 2.1[V], 2.2[V], 2.3[V]. As a result, it was confirmed that the relative humidity and temperature by regression each analysis, compared to the LPG characteristic graph and methane characteristics graph by a relative humidity of 0 ~ 85 [%] at a temperature range of $-10{\sim}40[^{\circ}C]$ show a similar linear pattern on the whore.

• 대기
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• 제31권3호
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• pp.295-309
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• 2021

Diurnal variations of air temperature and relative humidity in the Urban Canopy Layer (UCL) of the Seoul metropolitan area are examined using the Weather Research and Forecasting model coupled with the Seoul National University Urban Canopy Model. The canopy layer air temperature is higher than 2-m air temperature and exhibits a more rapid rise and an earlier peak in the daytime. These result from the multiple reflections of shortwave radiation and longwave radiation trapping due to the urban geometry. Because of the absence of vegetation in the UCL and the higher canopy layer air temperature, the canopy layer relative humidity is lower than 2-m relative humidity. Additional simulations with building height changes are conducted to examine the sensitivities of the canopy layer meteorological variables to the urban canyon aspect ratio. As the aspect ratio increases, net sensible heat flux entering the UCL increases (decreases) in the daytime (nighttime). However, the increase in the volume of the UCL reduces the magnitude of change rate of the canopy layer air temperature. As a result, the canopy layer air temperature generally decreases in the daytime and increases in the nighttime as the aspect ratio increases. The changes in the canopy layer relative humidity due to the aspect ratio change are largely determined by the canopy layer air temperature. As the aspect ratio increases, the canopy layer relative humidity is generally increased in the daytime and decreased in the nighttime, contrary to the canopy layer air temperature.

• 대기
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• 제24권1호
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• pp.69-76
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• 2014

Urbanization affects the local thermal environment due to the large scale land use changes. To investigate the weather environment change of large scale urban redevelopment, 9 surface temperature and humidity observations were accomplished at Eunpyeong new town area. The observation period is from March 2007 to February 2010. In the center of development area, the air temperature has increased and relative humidity has decreased, by the changes of the land cover and building construction. In the area where the green zone is maintained, air temperature and relative humidity were not changed significantly. The air temperature and relative humidity for the other development observation stations is decreased and increased, respectively. The relative temperature difference between study area and a neighboring rural location was increased during observation periods. The difference is the highest during winter. The urban-rural minimum temperature difference was increased at development area, which means that urbanization affects increasing of minimum temperature in study area.

• 보존과학연구
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• 통권24호
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• pp.169-184
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• 2003

Yearly mean temperature and relative-humidity of the Seokguram Grotto was measured $19~23^{\circ}C$, 40~44% from May, 1998 to December,2002. The measurement has little differences comparing to the optimum guideline (temperature : $20^{\circ}\pm2^{\circ}C$, relative-humidity : $50^{\circ}\pm5%$). It is necessary to increase humidity in the Seokguram Grotto during winter because of heating and decrease the temperature during summer because of a higher temperature of outside. In addition, the diurnal range keep in $4^{\circ}C$ of temperature and in 10% of relative-humidity. Yearly mean concentration of $CO_2$(carbon dioxide) was measured538~658ppm that is higher than concentration of normal atmosphere(360 ppm). The $CO_2$ has an cumulative effect on the surface of stone cultural properties as a form of carbonic acid($H_2CO_3$) after reaction with water. HVAC (Heating, Ventilation and Air Conditioning) system should be operated to maintain ideal state for the preservation according to the optimum guideline. Also, the entrance into the Seokguram Grotto should be controlled to prevent a sudden fluctuation of humidity and temperature. Human could carry small particles like a microdust, microbe, etc., into the Seokguram Grotto and also could damage the surface by a direct touch.

• 한국식품저장유통학회지
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• 제8권2호
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• pp.125-130
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• 2001

The effects of modified atmosphere(MA) storage for fresh red chili pepper and red bell pepper fruits were investigated with storing in polyethylene film with various fine holes. During the storage of the both pepper fruits, the weight loss, color change, mold emergence, and firmness were evaluated. The weight loss of pepper fruits packaged without holes on film was less than 3%, even though it was each 50% and 25% for non packaged red chili pepper and red bell pepper fruits. The rates of mold emergence of red chili pepper and red bell pepper fruits were reached to each 60% and 50% at the end of storage period as stored in film without holes. However, the rate of mold emergence of pepper fruits was lowered when fruits were stored in MA with low relative humidity (70∼80%). The color and firmness of pepper fruits were not much changed when fruits were stored in MA with high humidity.

• Journal of the Optical Society of Korea
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• 제19권1호
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• pp.1-6
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• 2015

We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of $CO_2$. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of $CO_2$ is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.

• 한국화재소방학회논문지
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• 제15권3호
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• pp.44-48
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• 2001

본 연구에서는, 접촉연소식 가스 탐지 소자를 대상으로 감도특성 및 전기적 특성을 분석하였으며, 24시간 동안 공기중에 노출시킨 후 온도($20^{\circ}c$, $40^{\circ}c$)와 상대습도(65%, 85%)에서 작동시켜 분석하였다. 또한 동일한 주거환경에서 210일 동안 50 cm/sec 유속을 유지하며 가스탐지소자의 동작을 실험하였다. 가스 탐지센서에 공급 전원은 기본회로에 직류 전압별(2.1V, 2.2V, 2.3V)로 인가하였다. 따라서, 상대습도와 온도에 의한 이소부탄과 메탄 특성그래프를 각각 분석한 결과 전반적으로 선형적인 증가를 보임을 확인할 수 있다.

• 대기
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• 제18권4호
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• pp.417-427
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• 2008

In this paper, we analyzed the physical and thermodynamic characteristics of fog by using the integrated water vapor (IWV) from Global Positioning System (GPS) networks and the regular observation data of meteorological stations in GPS sites. The cases of a radiation and an advection fog were selected as samples, the conversions of water substance from the water vapor to cloud water in fog were detected by the Bulk Water-Continuity Model, and the pattern analysis is adapted on GPS IWV, temperature, wind and relative humidity. Under the specific hypothesis (saturation and stable), GPS IWV could detect quantitatively the phase changing between the water vapor and cloud water content with condensation/evaporation during the formation and dissipation of fog. After it reaches to the saturation, the relative humidity can be a limited indicator for fog. However, GPS IWV can detect the status change of fog even after the saturation. It has indicated that GPS IWV could be a new observing technique for the processes of the fog formation and the dissipation.