• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1996.11a
• /
• pp.386-388
• /
• 1996

Low dielectric constant fluorinated oxide (SiOF) films were deposited using SiF$_4$/O$_2$/SiH$_4$mixtures by electron cyclotron resonance chemical vapor deposition (ECR CVD). Chemical composition of SiOF films was investigated by Fourier transform infrared spectroscopy (FT-lR). The fluorine content in the SiOF film observed by X-ray photoelectron spectroscopy (XPS). The dielectric constant decreased with increasing of the SiF$_4$ flow rate about 8sccm. The SiOF film, deposited with SiF$_4$=8 sccm, exhibited a F content of 5 atomic % and a relative dielectric constant 3.45. For evaluating SiOF films stability, humidity tests were performed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.11a
• /
• pp.343-346
• /
• 1995

In this paper, the effect of alkaline oxides on the humidity sensitivity of $V_2O_{5}$(2mol%)-doped $TiO_2$(98mol%) was investigated as functions of $Li_{2}Co_{3}$, $Na_{2}Co_{3}$. III-1. Measurement of Density. When the mole% of $Li_2$O is varied 0,1,2,5mol%, the more the mole% of additives is increased, the more difference of bulk and apparent density is largely narrowed. The difference of two densities of sample containing 2mol% $Na_2O$ was large all the moat. The sample containing 1mol% $Na_2O$ was small most. III-2. Observation of porosity. The porosity and total intrusion volume according to various amounts of $Li_2O$ was reduced and those of sample containing 2mol% $Na_2O$ as 31.13%, 0.1155mL/g was the highest and 1mol% $Na_2O$ was lowed most and 5, 10mol% $Na_2O$ was more high compare with sample without alkaline oxides. III-3. Characteristic of humidity sensitivity. 1. Impedance of samples containing $Li_2O$ was high compare with sample without alkaline oxides, so we thought it showed Poor sensitivity because it have no impedance changing rapidly as function of relative humidity. 2. When the humidity was increasing from 30RH% to 90RH%, the impedance of sample containing 2mol% $Na_2O$ at 120HZ changed exponential rapidly from 6${\times}$$10^{7}$$\Omega$) to 1.25${\times}$$10^4$$\Omega$. At under 50RH% and over 50RH%, the humidity sensitivity of samples containing 2mol% $Na_2O$ was best especially in the range of the low humidity. III-4. Characteristic of TG curves. When algal me oxide $M_{2}CO_{3}$(M=Li, Na) were added into $V_{2}O_{5}$-doped $TiO_2$, the stability of humidity sensitivity of samples containing amounts of $Li_2O$ was unstable. The samples containing 1mol% $Na_2O$ was unstable.

• KIEAE Journal
• /
• v.7 no.5
• /
• pp.87-92
• /
• 2007

As expansion of balconies at apartments has been legalized, the major function of the balconies as a thermal buffer zone is disappearing. This weakens the ability of window to insulate heat and multiplies surface condensation. Thus more and more residents require solutions to increasing surface condensation and aggravation in thermal comfort. This study intends to provide basic data by evaluating performance of triple layered Low-E windows, triple layered clear windows, double layered Low-E windows and double layered clear window used for expanded balconies and marketed within the country in terms of surface condensation and thermal environment through simulation. Results revealed that no surface condensation occurred at double layered Low-E windows and triple layered Low-E windows. Surface condensation took place at double layered clear windows and triple layered clear windows at a relative humidity of 60%. Thermal environment analysis suggested that double layered clear windows showed the most time falling into the range of comfort at $23^{\circ}C$. The figure were $22^{\circ}C$ for triple layered clear windows, $22^{\circ}C$ for double layered Low-E windows and $21^{\circ}C$ for triple layered Low-E windows.

• Journal of Korean Society of Forest Science
• /
• v.103 no.3
• /
• pp.368-374
• /
• 2014

This study was investigated the changes of storability and quality characteristics of 'Autumn Sense' hardy kiwifruit according to ethylene treatment and storage condition. In the results of investigation of changes in hardy kiwifruit quality during storage period, hardness of ethylene treated hardy kiwifruit during 48 and 96 hours was rapidly decreased, but soluble solid content was rapidly increased with the passing of storage period in all treatment groups. The total acid was estimated from 0.7 to 1.4% with storage period in all treatment groups. In the results of investigation of the weight loss rate, ethylene treated hardy kiwifruit during 48 hours was the highest 30.9% in storage at $20^{\circ}C$ and lowest 5.9% in storage at $2^{\circ}C$ with a relative air humidity of about 90% during storage at 24 days. Ethylene treated hardy kiwifruit during 96 hours was decrease 29.4% in storage at $20^{\circ}C$, 20.7% in storage at $4^{\circ}C$, 12.1% in storage at $2^{\circ}C$, and 6.0% in storage at $2^{\circ}C$ with a relative air humidity of about 90% during storage at 22 days. The taste of hardy kiwifruit during storage was reduced to increase in all treatment groups. Particularly, storage at $20^{\circ}C$ was rapidly reduced to increase in the early storage and storage at $2^{\circ}C$ with a relative air humidity of about 90% was decrease after storage at 18 days. The rotten rate during storage was increased in all treatment groups, storage at $20^{\circ}C$ was after storage at 2 days and storage at $2^{\circ}C$ with a relative air humidity of about 90% was rapidly increased after storage at 16 days. Thus, it can be recommended that storage at $2^{\circ}C$ with a relative air humidity of about 90% is good to maintain quality. Also, we will decide optimal storage condition and after-ripening time of 'Autumn Sense' hardy kiwifruit.

• Journal of Korean Society for Atmospheric Environment
• /
• v.33 no.6
• /
• pp.616-625
• /
• 2017

Measurements using five real-time particle samplers were compared to measurements using three NRM (National Reference Method system) filter-based samplers(Gravimetric method) at Incheon, Korea, between May and August, 2014. The purpose of this study was to suggest the quality assurance/quality control (QA/QC) method of each instrument for use in a real-time continuous particle sampler to measure the mass of airborne particles with an aerodynamic diameter less than $2.5{\mu}m$ ($PM_{2.5}$). Five real-time particle samplers of BAM1020, FH62C_14, TEOM, PM-711 and SPM-613 were evaluated by comparing its measured 23 hr average $PM_{2.5}$ concentrations with those measured with NRM filter-based samplers simultaneously. The parameters(e.g. Inlet heating condition, Slope factor, Film response, Intercept, Background, Span value) of the real-time samplers were optimized respectively by conducting test performance evaluation during 7 days in field sampling. For example, inlet heating temperature of TEOM sampler controls $35{\sim}40^{\circ}C$ to minimize the fluctuation of the real-time measurement data and background value of BAM1020 is the key factor affecting the accuracy of $PM_{2.5}$ mass concentration. We classified the $PM_{2.5}$ concentration according to relative humidity (80%) to identify water absorbed in aerosols by measuring the ${\beta}$-ray samplers(BAM1020, FH62C_14) and TEOM. ${\beta}$-ray samplers were not strongly affected by relative humidity that the difference of the average $PM_{2.5}$ concentration was about 5%. On the other hand, The TEOM sampler overestimated $PM_{2.5}$ mass concentration about 15% at low relative humidity (<80%).

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
• /
• v.25 no.1
• /
• pp.57-81
• /
• 1997

Numerical prediction of nocturnal thermal high in summer of the 1995 near Taegu city located in a basin has been carried out by a non-hydrostatic numerical model over complex terrain through one-way double nesting technique in the Z following coordinate system. Under the prevailing westerly winds, vertical turbulent fluxes of momentum and heat over mountains for daytime hours are quite strong with a large magnitude of more than $120W/\textrm{m}^2$, but a small one of $5W/\textrm{m}^2$ at the surface of the basin. Convective boundary layer (CBL) is developed with a thickness of about 600m over the ground in the lee side of Mt. Hyungje, and extends to the edge of inland at the interface of land sea in the east. Sensible heat flux near the surface of the top of the mountain is $50W/\textrm{m}^2$, but its flux in the basin is almost zero. Convergence of sensible heat flux occurs from the ground surface toward the atmosphere in the lower layer, causing the layer over the mountain to be warmed up, but no convergance of the flux over the basin results from the significant mixing of air within the CBL. As horizontal transport of sensible heat flux from the top of the mountain toward over the basin results in the continuous accumulation of heat with time, enhancing air temperature at the surface of the basin, especially Taegu city to be higher than $39.3^{\circ}C$. Since latent heat fluxes are $270W/\textrm{m}^2$ near the top of the mountain and $300W/\textrm{m}^2$ along the slope of the mountain and the basin, evaporation of water vapor from the surface of the basin is much higher than one from the mountain and then, horizontal transport of latent heat flux is from the basin toward the mountain, showing relative humidity of 65 to 75% over the mountain to be much greater than 50% to 55% in the basin. At night, sensible heat fluxes have negative values of $-120W/\textrm{m}^2$ along the slope near the top of the mountain and $-50W/\textrm{m}^2$ at the surface of the basin, which indicate gain of heat from the lower atmosphere. Nighttime radiative cooling produces a shallow nocturnal surface inversion layer with a thickness of about 100m, which is much lower than common surface inversion layer, and lifts extremely heated air masses for daytime hours, namely, a warm pool of $34^{\circ}C$ to be isolated over the ground surface in the basin. As heat transfer from the warm pool in the lower atmosphere toward the ground of the basin occurs, the air near the surface of the basin does not much cool down, resulting in the persistence of high temperature at night, called nocturnal thermal high or tropical night. High relative humidity of 75% is found at the surface of the basin under the moderate wind, while slightly low relative humidity of 60% is along the eastern slope of the high mountain, due to adiabatic heating by the srong downslope wind. Air temperature near the surface of the basin with high moisture in the evening does not get lower than that during the day and the high temperature produces nocturnal warming situation.

• Journal of Conservation Science
• /
• v.34 no.5
• /
• pp.387-396
• /
• 2018

Exposure to the natural environment can cause damage to domestic wooden cultural assets, such as temples. Deterioration is accelerated by biological damage and various environmental factors. In this study, meteorological factors were monitored by equipment installed at Beopjusa temple of Boeun province and Seonamsa temple of Suncheon province. A statistical model was applied to these data to predict the meteorological factors and to compare the predictive performance of each meteorological factor. The resulting correlation coefficient between air and dew point temperatures was highest, at 0.95, while the correlation coefficient for relative humidity had a moderate value(0.65) at both the Beopjusa and Seonamsa temples. Thus, a general linear model was found to be suitable for predicting air and dew point temperatures. An analysis of correlation between meteorological factors showed that there was strong positive correlation between air temperature and dew point temperature, and between solar radiation and evaporation at both sites. There was a weak positive correlation between air temperature and evaporation at Beopjusa temple. Wind speed was negatively correlated with both air temperature and relative humidity at Seonamsa temple. The wind speed at this location is higher than average in winter and lower than average in summer, and it was hypothesized that the low wind speed plays a role in reducing water evaporation in summer, when both air temperature and relative humidity are high. As a result, damage to the wooden buildings of Seonamsa temple is accelerated.

• Applied Biological Chemistry
• /
• v.21 no.3
• /
• pp.144-149
• /
• 1978

Fermented soy sauce was dehydrated by spray drying to form powder, and moisture sorption properties of powdered soy sauce with or without cover of the flexible films were examined on different relative humidity by using saturated salt solutions at $30^{\circ}$. The results obtained were summarized as follows: The equilibrium moisture content of spray-dried soy sauce containing 18.3% moisture was determined to 52% by graphical interpolation method, and E.M.C. of powdered soy sauce covered with plastic films decreased at low relative humidity whereas sharply increased curves were seen at high relative humidity. The rate constant of moisture adsortion K for the power covered with films were $66.2{\times}10^{-5}\;to\;225{\times}10^{-5}/hr$., and K' became greater when film having higher water vapor transmission rate was used. The shelf-life of powdered soy sauce covered with Al. foil/P.E. film by Brown formula at the accelerated condition of $38^{\circ}$, 92% R. H. was the longest period, 164 days compared with any other films used, and the shortest period, 18 days in P.V.C. film.

• Journal of Bio-Environment Control
• /
• v.30 no.1
• /
• pp.72-76
• /
• 2021

The amount of evapotranspiration (water absorption) according to wind speed showed the same trend in gold mound (Spiraea × bumalda), Japanese spurge (Pachysandra terminalis), and ivy (Hedera japonica Tobler). All the three plants showed maximum water absorption at 4 m·s-1; water absorption tended to decrease as wind speed decreased. The control group without wind speed treatment had the most amount of water absorption compared with the groups that were subjected to wind exposure. However, the plant growth of all three plants increased to the maximum value when wind speeds were 2 and 1 m·s-1. When comparing the relationship among water absorption, air temperature, and relative humidity, the water absorption of plants tended to be low from May 20 to 26, when air temperature and relative humidity were the lowest. The results of this study will help establish an urban wall-planting system taking building wind into consideration. Further, this study may help in the selection of plant types for ecological parks in windy islands.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.64 no.6
• /
• pp.65-75
• /
• 2022

Livestock industry in Korea has been growing rapidly and has reached 23 trillion Korean won in 2021. This study focuses on broiler, which is one of the largest sectors in livestock industry. As the effects of climate change get more serious, primary industry such as livestock industry is fragile to climate change since it directly interacts with nature. Therefore, maintaining suitable rearing environment is important. One of the most frequently used ventilation type for controlling the rearing environment of broiler house, tunnel ventilation, causes frequent air velocity fluctuation which makes maintaining the rearing environment important. By measuring the air temperature, relative humidity and air velocity in various points inside the broiler house, the internal thermal environment uniformity was analyzed according to length, width and zone. The experimental house was found to have dead zone with high air temperature, relative humidity and low air velocity near the end of the inlet and at the end of the broiler house. By using heat stress index to analyze quantitatively, zone with highest heat stress index was found to increase by 7.55% compared to the lowest zone. As a result, to maintain uniform rearing environment inside the broiler house, different factors must be measured and analyzed and used to operate the environmental control facilities.