• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.341-346
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• 2000

The effect of OTS(octadecyltrichlorosilane) SAM(self-assembled monolayer) on the micro-adhesion has been studied. OTS SAM was formed on the Si(100) surface and SPM (scanning probe microscope) tips with different radius of curvature were fabricated by a series of masking and etching processes. Pull-off forces of different tips on Si and OTS SAM surfaces were measured by SPM in different relative humidities. The surface of OTS SAM was changed to hydrophobic surface and the micro-adhesion force of OTS SAM was lower than that of pure Si. As the tip radius of curvature and the relative humidity increased. the micro-adhesion force increased. Based on the test results. the main parameter affected to the micro-adhesion was absorbed humidity on the surface.

• Wind and Structures
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• 제24권6호
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• pp.529-564
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• 2017

The Santa Ana winds occur in Southern California during the September-May time frame, bringing low humidities across the area and strong winds at favored locations, which include some mountain gaps and on particular slopes. The exceptionally strong event of late October 2007, which sparked and/or spread numerous fires across the region, is compared to more recent events using a numerical model verified against a very dense, limited-area network (mesonet) that has been recently deployed in San Diego County. The focus is placed on the spatial and temporal structure of the winds within the lowest two kilometers above the ground within the mesonet, along with an attempt to gauge winds and gusts occurring during and after the onset of October 2007's Witch fire, which became one of the largest wildfires in California history.

• 한국환경과학회지
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• 제29권12호
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• pp.1199-1204
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• 2020

Lentinula edodes mushrooms cultivated under different relative humidities were wrapped at 4℃ and the results of storage characteristics were investigated. Changes in water content of fruiting bodies during the storage period showed the highest water content in fruit bodies harvested from the treatment with the highest relative humidity. The luminosity of the fresh fruiting bodies showed no significant change during the storage period, and the redness was higher in the relative humidity 95% treatment than in the other treatments. According to this study, the relative humidity of the pileus was 65%, and the content of Ergosterol was 0.67 ± 15 g / L at relative humidity of 65%, 80% and 95%. In addition, amino acid analysis and Principal Component Analysis (PCA) confirmed that methionine was the main cause of changes in storage time and relative humidity.

• Journal of the Korean Wood Science and Technology
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• 제16권4호
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• pp.10-39
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• 1988

This study investigated the temperatures and relative humidities in the semi-greenhouse type solar dryer with a black rock-bed heat storage and without heat storage and outdoor temperature and relative humidity at 9 a.m. and 2 p.m.. A comparison was made of the drying rates, final moisture contents, moisture content distributions, casehardening stresses, drying defects, volumetric shrinkage of dried lumber for solar- and air-drying from the green condition of mixtures of Douglas-fir, lauan, taun, oak and sycamore 25mm- and 50 mm-thick lumber during the same period for four seasons, and heat efficiencies for solar dryer with and without the heat storage for saving of heat energy and the cost of lumber drying using the solar energy. The results from this study were summarized as follows: I. The mean weekly temperatures in the solar dryers were 3 to $6^{\circ}C$ at 9 a.m. and 9 to $13^{\circ}C$ at 2 p.m. higher than mean outdoor temperature during all the drying period. 2. The mean weekly relative humidities in the solar dryers were about 1 to 19% at 9 a.m. higher than the outdoor relative humidity. and the difference between indoor and outdoor relative humidity in the morning was greater than in the afternoon. 3. The temperatures and relative humidities in the solar dryer with and without the heat storage were nearly same. 4. The overall solar insolation during the spring months was highest and then was greater in the order of summer, atumm, and winter month. S. The initial rate of solar drying was more rapid than that of air drying. As moisture content decreased, solar drying rate became more rapid than that of air drying. The rates of solar drying with and without heat storage were nearly same. The drying rate of Douglas-fir was fastest and then faster in the order of sycamore, lauan, taun and oak. and the faster drying rate of species, the smaller differences of drying rates between thicknesses of lumber. The drying rates were fastest in the summer and slowest in the winter. The rates of solar drying during the spring were more slowly in the early stage and faster in the later stage than those during the autumn. 6. The final moisture contents were above 15% for 25mm-thick air dried and about 10% for solar dried lumber, but the mean final MCs for 50mm-thick lumber were much higher than those of thin lumber. The differences of final MC between upper and lower course of pile for solar drying were greater than those of pile for air drying. The differences of moisture content between the shell and the core of air dried lumbers were greater than those of solar dried lumber, smallest in the drying during summer and greatest in the drying during winter among seasons. 7. Casehardening stresses of 25mm- and 50mm-thick dried lumber were slight, casehardening stress of solar dried lumber was severer than that of air dried lumber and was similar between solar dried lumber with and without heat storage, Casehardening stresses of lumber dried during spring were slightest and then slighter in the order of summer, autumn, and winter. Casehardening stresses of Douglas -fir, sycamore and lauan were slight, comparing with those of taun and oak. 8. Maximum initial checks of 25mm-thick lumber occurred above and below fiber saturation point and those of 50mm-thick lumber occurred in the higher moisture content than thin lumber. As the moisture content decreased, most of checks were closed and didn't show distinct difference of the degree of checks among drying methods. The degree of checks were very slight in case of Douglas-fir and lauan, and severe in case of taun and oak. The degree of checks for 50mm-thick lumber were severer than those for 25mm-thick lumber. 9. The degree of warpage showed severe in case of oak and sycamore lumber, but no warping was found in case of Douglas-fir, lauan and taun. 10. The volumetric shrinkages of taun and oak were large and medium in case of Douglas-fir, lauan and sycamore. 11. Heat efficiencies of solar dryer with heat storage were 6.9% during spring, 7.7% during summer, 12.1% during autumn and 4.1% during winter season. Heat efficiency of solar dryer with heat storage was slightly greater than that of without heat storage. As moisture content of lumber decreased, heat efficiency decreased.

• 한국산업보건학회지
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• 제5권2호
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• pp.200-211
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• 1995

This study was designed to evaluate the effects of temperature and humidity on the sampling efficiency of mixed organic vapors of l,2-DCE, benzene, and MIBK by 3 different types of diffusion monitors. Independent variables used for the study were temperatures ($25^{\circ}C$, $35^{\circ}C$), humidities (30%, 80%), and vapor concentrations (low, medium, and high). In addition, vapor concentrations measured by the traditional charcoal tube method were used as reference values and were compared with those of by diffusion monitors. The results were as follows: 1. The desorption efficiencies(DE) of 1,2-DCE and benzene from charcoal tubes and from diffusion monitors ranged from 98% to 105%. In contrast, the DEs of MIBK from charcoal tubes and diffusion monitors except DM1 ranged from 71% to 85%. The DE of MIBK from DM1 was 98%. 2. No statistically significant differences of 1,2-DCE concentrations and the sampling efficiencies regardless of temperatures and humidities studied between charcoal tube and 3 diffusion monitors were found. 3. At 80% humidity, increasing frequencies of 1,2-DCE breakthrough at higher temperature and higher vapor concentration measured by charcoal tubes were observed. 4. No statistically significant difference of benzene concentrations were found between charcoal tube and diffusion monitors except DM3. The sampling efficiencies of DM3 were statistically significantly lower at all experimental conditions except the $35^{\circ}C$ and 30% humidity condition. 5. No statistically significant difference of MIBK concentrations were found between charcoal tube and diffusion monitors except DM3. The sampling efficiencies of DM3 were statistically significantly higher at higher humidity conditions regardless of temperature. Although statistically not significant, sampling efficiency of MIBK showed positive correlation with humidity while negative correlation with concentration was observed. 6. For sampling 1,2-DCE and benzene, no significant variations of concentrations among three diffusion monitors regardless of temperature and humidity conditions were found. For MIBK sampling, however, wide variations with increasing humidity among diffusion monitors were obtained. In conclusion, this study suggests that diffusion monitors will be a reasonables substitute for the traditional charcoal tubes for sampling non-polar organic vapors at temperature and humidity conditions studied. For polar organic vapors, use of an alternative desorption solution other than CS2 is recommended because of its low desorption efficiency. In addition, since variable among diffusion monitors for polar organic vapors particularly at higher humidity conditions were observed, further study is recommended of the effects of humidity on the performance of diffusion monitors.

• 한국식품과학회지
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• 제31권1호
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• pp.128-137
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• 1999

현재 조미료 및 부침가루로 사용되고 있는 표고버섯분말을 사용하여 열풍건조, 진공건조, 동결건조를 이용하여 건조를 행하였다. 각 건조 방법별로 표고버섯분말은 조직구조 및 물리적 특성치인 pore size도 다르게 나타났다. 또한 건조 방법별로 품질 분석을 한 결과 일반성분에서는 초기 수분함량에서 다소 차이가 있었으나 전체적인 차이는 크게 나지 않았다. 또한 건조 표고버섯의 맛 성분인 핵산을 분석한 결과에서도 큰 차이를 나타내지 않았으며, 총페놀 함량에서도 유사한 결과를 나타냈다. 이러한 결과를 토대로 표고버섯 분말의 흡습특성을 조사한 결과 pore size가 가장 큰 동결건조에서 가장 높은 흡습량을 가져왔으며, pore size의 크기에 따라 진공건조, 열풍건조 순으로 흡습량이 많았다. 그리고 저장 온도별로는 가장 낮은 온도인 $5^{\circ}C$에서 가장 높은 흡습을 보여주었으며, $35^{\circ}C$에서는 흡습량이 상대적으로 낮았다. 그러나 $35^{\circ}C$ 상대 습도 84%의 저장온도에서는 진공건조 및 동결건조 시료에서 저장 11일만에 곰팡이가 생겨났으므로 평형수분함량을 측정하지 못하였다. 저장 적정 수분함량을 구하기 위해 단분자층 수분함량을 구한 결과는 동결건조한 시료가 다른 시료보다 높은 값을 나타내었고, 흡습 엔탈피는 동결건조한 것이 가장 높은 값을 보여주었다. 또한 표고버섯분말의 평형수분함량 예측을 위해 현재까지 가장 적합성이 높다는 여러 가지 식으로 적합성을 살펴본 결과 단백질 함량이 비슷한 Khun식과 Mizrahi 식이 적합성이 가장 높았다. 그러나 이러한 식들은 상대습도만으로 구한 값이므로 상대습도뿐만 아니라 온도 및 공극을 변수로 넣어 회귀식을 도출한 결과 $R^2$가 0.989의 적용도가 높은 식을 구하였다.

• 한국식품영양과학회지
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• 제18권4호
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• pp.398-402
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• 1989

우리나라 장려콩 2품종(장엽과 황금)을 대상으로 흡습 및 조리성질을 조사하였다. 시료콩을 상대습도 $33{\sim}86%$, 온도 $16^{\circ}C$에서 125시간 저장할 때 상대습도 33%와 44%에서는 탈습, 그 이상의 저장습도에서는 흡습현상을 보여주었다. 흡습속도는 저장시간에 따라 크게 감소하였으며, 그 절대값은 저장습도가 높을수록 컸었다. 저장시간과 흡습속도와의 관계는 흡습속도식 $log\frac{dw}{dt}=b\;logt+loga$(여기에서 w는 수분함량, t는 시간, b와 a는 상수)에 잘 적용되었으며, 식에서 구한 수분함량과 실측치는 일치 하였다. 한편 $106{\sim}121^{\circ}C$의 온도에서 증자후 최대절단력으로 조리도를 비교한 결과 증자온도의 상승에 따라 일정한 조리도에 도달하는 시간은 대수적으로 감소하였다. 일정한 조리도를 나타내는 온도-시간과의 관계로부터 구한 z-값은 장엽콩이 $13.3^{\circ}C$, 황금콩이 $12.8^{\circ}C$이었다.

• 한국의류학회지
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• 제16권2호
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• pp.245-254
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• 1992

The purpose of this study was to evaluate the mechanical thermal resistances and comfort properties of ski wear made with vapor-permeable water repellent (VPWR) fabrics and thermal insulation battings. Four types of experimental clothing were made with the combination of two VPWR fabrics (Hipora-$TM^{\circledR}$, Hipora-$CR^{\circledR}$) and two thermal insulation battings ($Viwarm^{\circledR},\;Airseal^{\circledR}$). Thermal resistances of ski wear were objectly evaluated by thermal manikin experiment ($21{\pm}\;2^{\circ}C,\;50{\pm}5\%$ R.H.,0.25 m/sec air velocity) and thermographic accessment ($2{\pm}2^{\circ}C,\;0\%$ R.H.,0.25 m/sec air velocity, and emissivity level : 1). Garment wear tests of ski wear included the measurement of the microclimate (inner temp. and relative humidity) of the experimental clothing by digital thermohygrometer and subject wear sensation using McNall's thermal comfort ratings. CBo values of experimental clothing 4 (Hipora-$CR^{\circledR}+Airseal^{\circledR}$) and 1 (Hipora-$TM^{\circledR}+Viwarm^{\circledR}$) were significantly higher than those of 2 (Hipora-$TM^{\circledR}+Airseal^{\circledR}$) and 3 (Hipora-$CR^{\circledR}+Viwarm^{\circledR}$). Thermal resistances in the points of breast, back, belly, and loin was significantly higher than those of upper am, fore arm, and shank of measuring points on the thermal manikin. According to the color map of the thermogram, the experimental clothing 4 indicated higher surface temperatures than the others showing more yellowish spots on the surface of clothing. Inner temperature of experimental clothing was not significantly different among the four types of ski wear, but relative humidities of experimental clothing were significantly different. Relative humidities of experimental clothing 1 and 3 showed higher than those of 2 and 4. Relative humidity of experimantal clothing was affected largely by the thermal resis- tance of thermal insulation batting materials. The subject wear sensation of experimental clothing 2 and 4 showed lower humidity than the others. Subject wear sensation was affected more by humidity sensation than by thermal sensation.

• 동아시아식생활학회지
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• 제27권5호
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• pp.576-582
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• 2017

본 연구는 기후변화에 따른 온도 및 습도 상승에 대한 건조분말 식품에서의 미생물적인 품질 변화를 평가하였다. 건조분말 시료를 고온 및 다양한 상대습도에서 저장하며 총균수, 대장균군, 효모 및 곰팡이를 측정한 결과 높은 상대습도에서 건조분말 식품의 수분활성도가 유의적으로 증가하였으며, 총균수와 진균류가 저장기간 동안 유의적으로 증가하는 것으로 나타났다. 특히, 진균류는 저장 기간 동안 건조분말식품의 수분활성도의 증가와 높은 상관성을 나타내어 건조분말 식품의 보관 시 가장 관리가 필요한 미생물 군으로 확인되었다. 반면 상대습도 85% 이하에서는 미생물의 높은 생육이 관찰되지 않아 건조분말 식품의 보관에서 저장 중 상대습도의 관리가 매우 중요함을 알 수 있다. 건조분말 식품은 낮은 수분활성도로 인하여 개봉 후에도 주로 상온에 장기간 보관하는 식품이다. 하지만 본 연구결과로부터 높은 상대습도는 건조분말 식품의 수분활성도와 미생물 품질에 유의적인 영향을 줄 수 있으므로, 개봉된 건조분말 식품은 밀봉하거나, 냉장 보관하는 등 저장 시 온도 및 습도를 철저히 관리할 필요가 있다.

• 공업화학
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• 제16권2호
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• pp.194-199
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• 2005

본 연구에서는 배연가스속에 함유되어 있는 휘발성 유기화합물과 입자물질 등의 오염물질을 보텍스 사이클론의 원리를 이용하여 동시에 제거하는 메카니즘을 규명하고 나아가 효율을 높이기 위한 영향인자들을 분석 하였다. 보텍스 사이클론 속에 접선방향으로 압축된 공기를 주입함으로써 Joule-Thomson 팽창에 의하여 형성된 저온부분에서 페놀, 탄산가스 및 수분이 활성탄소 입자표면에 응집, 응축 및 흡착이 일어나도록 하였다. 활성탄소와 같은 입자물질은 쉽게 응축될 수 있는 물질들이 저절로 응집이나 응축은 입자물질의 입경이 증가함에 따라 속도는 급속도로 빨라져서 제거효율이 상승된다. 본 연구실험에서 탄산가스와 페놀의 제거효율은 각각 87.3%와 93.8%로 얻어졌다. 그리고 페놀 제거효율은 톨루엔과는 달리 상대습도의 증가에 따라 함께 증가되었고, 활성탄의 주입으로 제거효율도 증폭되었다. Joule-Thomson 계수는 상대습도 10%~50% 범위에서는 도입되는 압력이 높아짐에 따라 같이 상승하였다. 실험의 결과로는 도입되는 압력과 수분이 보텍스 사이클론의 처리효율에 미치는 영향은 공기 속에 함유되어 있는 대상물질의 물리화학적 특성과 입자물질의 특성에 따라 많은 영향을 받고 있음을 알 수 있고, 따라서 휘발성 유기화합물의 제거효율은 수분의 양과 입자물질의 물리화학적 특성을 조절함으로 제어할 수 있다고 판단된다.