• 제목/요약/키워드: Relative Humidity

검색결과 2,542건 처리시간 0.027초

EVAPOTRANSPIRATION RATE AND GRAFT-TAKING OF GRAFTED SEEDLINGS UNDER ARTIFICIAL LIGHTING

  • Kim, Y. H.
    • 한국농업기계학회:학술대회논문집
    • /
    • 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
    • /
    • pp.632-638
    • /
    • 2000
  • This paper represents the characteristics of evapotranspiration rate (EVTR) and graft-taking of watermelon grafted seedlings in a graft-taking enhancement system using fluorescent lamps as artificial lighting source. Four air temperature levels of 23, 25, 27 and 29C, three humidity levels of 85, 90 and 95%R.H. and two photosynthetic photon flux (PPF) levels of 30 and 50 ${\mu}$mol m$\^$-2/ S$\^$-1/ were provided to investigate the effects of air temperature, relative humidity and light intensity on EVTR and graft-taking of grafted seedlings. EVTR of grafted seedlings increased with increasing air temperature and the passage of time after grafting. Also EVTR increased with decreasing relative humidity. As relative humidity decreased and air temperature increased, vapor pressure deficit increased and thus EVTR increased. It is required to maintain a low level vapor pressure deficit for suppressing EVTR of grafted seedlings during first 1-2 days after grafting. Therefore, less EVTR at initial stage after grafting would be adequate for smooth joining of the scion and rootstock.

  • PDF

ZnS:Cu 형광체의 전계 발광 및 가속열화 특성 (Electroluminescent and Accelerated Aging Properties of ZnS:Cu Phosphor)

  • 이종찬;황명근;박대희
    • 한국조명전기설비학회:학술대회논문집
    • /
    • 한국조명전기설비학회 2001년도 학술대회논문집
    • /
    • pp.13-16
    • /
    • 2001
  • In this paper, the emission and aging properties of ZnS:Cu electroluminescent device were experiment respectively at room temperature and 7$0^{\circ}C$ relative humidity 100%. ZnS:Cu and BaTiO$_3$were respectively used for phosphor and dielectric. While AC 100V on 400Hz frequency were applied to the devices at room temperature and 70$_3$relative humidity 100%, the change of brightness were measured and compared. The surface of aged devices were investigated by scanning electron microscope. With the continuously operated environment of room temperature and 7$0^{\circ}C$ relative humidity 100%, the decay time were measured and the dark spot and aging status on the surface of the device were investigated. ZnS:Cu electroluminescent properties were deteriorated by the Increased temperature and humidity. Also the deteriorated properties were confirmed by the brightness and surface chanties of device, and the aging mechanism from the simulation on sulfur vacancy and deep tracts density.

  • PDF

수동급기 직접 메탄올 연료전지의 공기극 물 관리 (Water management for vapor-fed direct methanol fuel cells)

  • 장익황;차석원;하승범;이윤호
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
    • /
    • pp.319-322
    • /
    • 2009
  • This paper investigated environmental effects for passive, air-breathing, and vapor-feeding direct methanol fuel cells. In these experiments, experimental parameters are temperature($30^{\circ}C$, $40^{\circ}C$ and relative humidity(25%, 50%, 75%). From these experimental results, the water contents play a key role in terms of optimal ionic conductivity at the cathode catalyst layer. In case of pure methanol feeding, the performance is inversely proportional to the relative humidity. The water generation resulting from methanol crossover maintains ionic conductivity at the cathode. On the contrary, diluted methanol solution (50wt.%) lowers methanol crossover to the cathode. In order to increase ionic conductivity, the relatively high humidity is required to the cathode catalyst layer for the water generation. The relative humidity scales with the performance.

  • PDF

하드디스크 DLC 필름의 마찰 마모특성에 대한 온도와 습도의 영향 (Effects of Temperature and Humidity on the Friction and Wear Properties of DLC Film on the Hard Disk)

  • 안준양;김대은
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 추계학술대회논문집A
    • /
    • pp.876-881
    • /
    • 2001
  • DLC(Diamond-like carbon) films possess high hardness, low friction coefficient, and good wear resistance. Due to these properties, DLC films have been used extensively in magnetic hard disk industry. The objective of the present study was to investigate the influence of environmental condition on the tribological behavior of DLC coated hard disk. It is found that the tribological characteristics of DLC films are strongly affected by relative humidity and temperature. Specifically, the friction coefficient increases with increase in temperature at relative humidity of 50%. However, at 20% and 85% RH the effect of temperature was not significant. Also, the degree of wear could be observed using an AFM.

  • PDF

철근콘크리트 내부 온습도 경시변화 추정 모델 구축 (Prediction Model for the Change of Temperature and R.H. inside Reinforced Concrete)

  • 박동천
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2016년도 추계 학술논문 발표대회
    • /
    • pp.83-84
    • /
    • 2016
  • Surplus water inside a concrete other than moisture that is used for hydration of the cement affects the physical properties of the concrete (modulus of elasticity, compressive strength, drying shrinkage, and creep) by drying. Changes in temperature and humidity inside a concrete has correlation with the movement speed and reaction rate of deterioration factors such as carbon dioxide and chloride ions. In this study, comparison was performed between temperature and relative humidity inside the concrete and meteorological data for exposure environment through measurement at the site for two years. Surface temperature of the concrete (depth 1cm) was measured higher by 6℃ during the summers, while it was measured lower by 2℃ during the winters due to solar radiation, wind, and radiation cooling. As for relative humidity, change was large in the depth of 1cm, while more than 85% was maintained in the depth of 10cm.

  • PDF

드론을 이용한 안면도 상공 대기경계층내의 미세먼지 연직분포 및 Flux 측정 (Vertical Aerosol Distribution and Flux Measurement in the Planetary Boundary Layer Using Drone)

  • 김희상;박용희;김우영;은희람;안강호
    • 한국입자에어로졸학회지
    • /
    • 제14권2호
    • /
    • pp.35-40
    • /
    • 2018
  • Vertical particle size distribution, total particle concentration, wind velocity, temperature and humidity measurement was performed with a drone. The drone was equipped with a wind sensor, house-made optical particle count(Hy-OPC), condensation particle counter(Hy-CPC), GPS, Temperature, Relative Humidity, Pressure and communication system. Base on the wind velocity and the particle size vertical distribution measurement with drone, the particle mass flux was calculated. The vertical particle distribution showed that the particle number concentration was very strongly correlated with the relative humidity.

건축자재 내의 수분이 곰팡이 성장에 미치는 영향 (Influence of Moisture on Mold Growth in Building Materials)

  • 서장후
    • 설비공학논문집
    • /
    • 제24권12호
    • /
    • pp.852-857
    • /
    • 2012
  • Recently, the indoor air pollution by microbes such as fungi and mites have become a concern as important research topic on indoor air quality. Fungal growth is significantly affected by humidity. In this study, we examined the influence of relative humidity on the surface of building materials and the water content of building materials on the fungal growth rate by measuring the mycelium length of fungi in the fungal detector placed on the surface of building materials. As a result, even if the relative humidity on the surface of building materials is identical, the more water content of building materials is, the more fungi grow faster. It was suggested that fungal growth rate depends on not only the relative humidity on the surface of building materials but also the water content of building materials.

질화탄소막의 물리적 특성과 센서재료 응용에 관한 연구 (A Study on Physical Properties of Carbon Nitride Films and Application of Sensor Materials)

  • 김성엽;이지공;장중원;이성필
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
    • /
    • pp.247-248
    • /
    • 2006
  • Carbon nitride films were evaluated that they had many advantages for miniature micro-humidity-sensors using the standard CMOS technology humidity sensing properties and CV characteristics of the carbon nitride films have been investigated for fabricating one chip HUSFET(Humidity Sensitive Field Effect Transistor) humidity sensors Carbon nitride films were deposited on silicon substrate with meshed electrodes by reactive RF magnetron sputtering system. The capacitor-type humidity sensor revealed good humidity-impedance characteristics with a wide range of relative humidity changes, decreasing $254k{\Omega}$ to $16k{\Omega}$ according to increase of relative humidity between 5% ~ 95% and the films were very stable on the Si wafer. These results reveal that $CN_x$ thin films can be used for Si based or HUSFET structure one chip micro-humidity sensors.

  • PDF

냉방부하 추정을 위한 온도와 습도 예측에 관한 연구 (A Study on Prediction of Temperature and Humidity for Estimation of Cooling Load)

  • 유성연;이제묘;한규현;한승호
    • 설비공학논문집
    • /
    • 제19권5호
    • /
    • pp.394-402
    • /
    • 2007
  • To estimate the cooling load for the following day, outdoor temperature and humidity are needed in hourly base. But the meteorological administration forecasts only maximum and minimum temperature. New methodology is proposed for predicting hourly outdoor temperature and humidity by using the forecasted maximum and minimum temperature. The correlations for normalized outdoor temperature and specific humidity has been derived from the weather data for five years from 2001 to 2005 at Seoul, Daejeon and Pusan. The correlations for normalized temperature are independent of date, while the correlations for specific humidity are linearly dependent on date. The predicted results show fairly good agreement with the measured data. The prediction program is also developed for hourly outdoor dry bulb temperature, specific humidity, dew point, relative humidity, enthalpy and specific volume.

A Humidity Sensor Using an Electrochemically Prepared Poly(1,5-Diaminonaphthalene)Film

  • 박덕수;심윤보
    • 센서학회지
    • /
    • 제12권6호
    • /
    • pp.241-248
    • /
    • 2003
  • An electrochemical humidity sensor was fabricated with poly(1,5-diaminonaphthalene) film coated on a gap of two splitted gold electrodes, which were made by vacuum deposition. Response currents according to humidity were measured by the potential sweep method and chronoamperometry. The stability of the polymer film was improved by double step chronoamperometry using the applied voltage of ${\pm}0.5$ Vdc. The response time determined by the pulse technique was about ${\sim}50$ msec and the relative standard deviation of current response was within ${\pm}5.0%$. The response current of the film was intrinsically humidity dependent. The film exhibited a non-linear but reproducible response in ordinary range of relative humidity. The linear equations were $I(nA)=0.28{\times}%RH-1.01$ between 10 to 70 %RH and $I(nA)=6.05{\times}%RH-403.21$ between 70 to 90 %RH.