• Journal of Environmental Science International
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• v.14 no.1
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• pp.91-96
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• 2005

Several samplers using gravimetric methods such as high-volume air sampler, MiniVol portable sampler, personal environmental monitor(PEM) and cyclone were applied to determine the concentrations of fine particles in atmospheric condition. Comparative evaluation between high-volume air sampler and Minivol portable sampler for $PM_{10}$, and between Minivol portable sampler and PEM was undertaken from June, 2003 to January 2004. Simultaneously, meteorological conditions such as wind speed, wind direction, relative humidity and temperature was measured to check the factors affecting the concentrations of fine particles. In addition, particle concen­trations by cyclone with an aerodynamic diameter of $4{\mu}m$ were measured. Correlation coefficient between high­volume air sampler and portable air sampler for $PM_{10}$ was 0.79 (p<0.001). However, the mean concentration for $PM_{10}$ by high-volume air sampler was significantly higher than that by Minivol portable sampler (p=0.018). Correlation coefficient between Minivol portable sampler and PEM for $PM_{2.5}$ as 0.74 (p<0.001), and the measured mean concentrations for $PM_{2.5}$ did not show significant difference. Difference of the measured con­centrations of fine particle might be explained by wind speed and humidity among meteorological conditions. Particle concentration differences by measurement samplers were proportional to the wind speed, but inversely proportional to the relative humidity, though it was not a significant correlation.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.395-403
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• 2013

Plant factory has drawn attention in many countries in the world due to capability of environmental control not only for better yield and quality, but also for increase in functional and medicinal components of the products. In this paper, an experimental plant factory was constructed for various tests under different environmental conditions, and the operations were evaluated. A production room was constructed with adiabatic materials with dimensions of $6,900{\times}3,000{\times}2,500$ mm ($L{\times}W{\times}H$). Four sets of $2,890{\times}600{\times}2,320$ mm ($L{\times}W{\times}H$) production frame unit, each with 9 light-installed beds and an aeroponic fertigation system, resulting in 36 beds, were prepared. Accuracy and response were evaluated for each environmental control component with and without crops. Air temperature, humidity, $CO_2$ concentration, light intensity, frequency, and duty ratio, fertigation rate and scheduling were controllable from a main control computer through wireless communication devices. When the plant factory was operated without crop condition, the response times were 8 minutes for change in temperature from 20 to $15^{\circ}C$ and 20 minutes from 15 to $20^{\circ}C$; 7 minutes for change in humidity from 40 to 65%; and 4 minutes for change in $CO_2$ concentration from 450 to 1000 ppm. When operated for 24 hours with crop cultivation; average, maximum, and minimum values of temperatures were 20.06, 20.8, and $18.8^{\circ}C$; humidity were 66.72, 69.37, and 63.73%; $CO_2$ concentrations were 1017, 1168, and 911 ppm, respectively. Photosynthetic Photon Flux Density was increased as the distance from the light source decreased, but variability was greater at shorter distances. Results of the study would provide useful information for efficient application of the plant factory and to investigate the optimum environment for crop growth through various experiments.

• The Korean Journal of Community Living Science
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• v.17 no.1
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• pp.101-108
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• 2006

This study was conducted to develop the regulating methods for the optimal harvest stage of new sprout for woody plants, and to clarify the effects of storage condition and period on the growth of new sprout formed of Aralia elata cv. 'Jeongkwang'. Japanese angelica tree were collected in the Jangheung district of Jeonnam on 20. March, 2005, and those cut branches were stored at $5{\pm}2^{\circ}C$ and 80 to 90% of the relative humidity, and were cut in water. Survival rate of cut branches for Aralia elata cv. 'Jeongkwang' was significantly increased when that was used for the cutting after the collection with no storage. And those survival rate was much more increased when that was stored at 80 to 90% of relative humidity than 40 to 50% of relative humidity. Number of new sprouts formed which were not stored immediately after the collection 3.2 to 3.4, and that were stored at cold storage room before cutting and cut on 1. June and 1. August were 5.1 to 5.3. Leaf growth of cut branches cut in water on 20. March started at ten days after cutting, and that on 1. June and 1. August at one to two days after cutting. Slow and mature sprout growth of Aralia elata cv. 'Jeongkwang' which were cut in water were different by the cold storage periods. Nineteen days were needed for the mature growth of sprout when cut in water on 20. March, and thirteen days on 1. August.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.12
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• pp.25-29
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• 1972

This experiment was carried out to investigate the role of Silicon accumlated in rice plant under different conditions of light and humidity, using radioisotopes Ca-45, Mn-54, and P-32. This results obtained in are as follows; 1. Light effect is more severe in phosphate uptake by rice plant than is calcium. Amounts of phosphate uptake in light condition is six times more than in dark conditions, while that of calcium is double. 2. Change of relative humidity affects calcium absorption and transport from root to shoot. It seems not to be influenced in phosphate and manganese uptake by relative humidity. 3. More uptake of each element Ca-45, P-32, or Mn-54 was found in the rice plant applied with silicic acid. It is considered that there must be some relationship between silicon content and ion uptake in rice plant. 4. The transport ratio of nutrient from root to shoot shows a specific pattern that calcium is approximately 1.0 manganese 0.5 and phosphate 0.2 respectively.

• Journal of the Korean Society of Tobacco Science
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• v.29 no.2
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• pp.66-73
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• 2007

This study was carried out to investigate the changes of curing condition on microclimate of temperature, relative humidity during curing process of burley tobacco leaves. The developed facility, ridge opening type was designed to open the central top roof. The air-cured variety, (N. tabacum cv KB111) was normally grown at the Eumseong tobacco experimental station in 2007. Mean daily temperature of $3^{\circ}C$ in ridge opening type curing facility was lower than that of conventional, whereas mean daily relative humidity of 12.6 % RH was lower in conventional curing facility for the entire stage of curing. The frequency distribution of optimal air temperature at daytime was higher 37.5 % in ridge opening type curing facility than that of conventional, while that of optimal relative humidity was lower 8.2 %. In the ridge opening type curing facility, the excessive drying leaves were low, however the price per kilogram was high. These results suggest that the new developed curing facility may be applied to improved microclimate inside the curing facility for curing burley.

• Journal of Korean Society of societal Security
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• v.1 no.3
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• pp.51-57
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• 2008

The long-term behaviors of prestressed concrete cable-stayed bridges are considerably influenced by the time dependant material characteristics such as creep and shrinkage. This study investigated the influences of the change of relative humidity by application of the CEB-FIP model and ACI model, which are generally used in the prediction of long-term behavior of concrete structures. In case of the moment of girder, CEB-FIP model predicted a bigger effect of relative humidity change than the ACI model. Furthermore, the effect was significant. Also, the long-term behaviors between these models were different each other even under the same material condition. Therefore, the prediction of the long-term behavior should be compensated after comparative analysis with the results of material tests of each construction site and between the different models.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.114-122
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• 2014

Currently, global warming has become a serious problem arising from the usage of fossil fuels such as coal and petroleum. Moreover, due to the global warming, heat wave, heavy snow, heavy rain, super typhoon are frequently occurring all over the world. Due to these serious natural disasters, concrete structures and infrastructures are seriously damaged or collapsed. In order to handle these problems, climate change oriented construction technology and codes are necessary at this time. Therefore, in this study, the validity of the present concrete mixture proportions are evaluated considering temperature and humidity change. The specimens cured at various temperature and humidity conditions were tested to obtain their compressive and split tensile strengths at various curing ages. Moreover, performance based evaluation (PBE) method was used to analyze the satisfaction percentage of the concrete cured at various condition. From the probabilistic method of performance evaluation of concrete performance, feasibility and usability can be determined for future concrete mix design.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.556-560
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• 2013

Recently, there are many efforts focused on development of more economical non-fluorinated membranes for use in PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, characteristics of poly(arylene ether sulfone)(PAES) were compared with fluorinated membrane at PEMFC operation condition. I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. PAES membrane showed similar performance compared with fluorinated membrane at 100% relative humidity, but the performance of PAES membrane decreased largely due to low ionic conductivity at low relative humidity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1789-1794
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• 2009

In the present study, the cooling performance characteristics on environment changes of A/C applied fin-tube and PF heat exchangers were experimentally investigated. Capacity and COP on an air velocity, an indoor/outdoor temperature and an indoor/outdoor relative humidity were obtained. Fin types of PF heat exchanger were a triangler and squarer form. The experimental data for the three kinds of heat exchangers were measured using the air-enthalpy calorimeter. Performance of PF A/C was more excellent than that of a fin-tube A/C. Also, the performance of PF-2 A/C with the squarer fin was more excellent than that of PF-1 A/C with the triangler fin. As the air velocity, the indoor temperature and the indoor relative humidity increase, capacity and COP increase. And as outdoor temperature increases, capacity and COP decrease. But, the performance change on the outdoor relative humidity was insignificant.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.1
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• pp.50-58
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• 1998

Water vapor transmission was tested in water bath controlled by $20^{\cire}C$, 90%RH for T800/AD6005 based composite motor case which made by filament winding method. We detected internal relative humidity of composite motor case by inserting the humidity detector through the head of motor case for the study of humidity transmission through the wall of composite motor case. We found out that this composite material appears the water vapor flux of 2.88${\times}$$10^{-9}$g/$\textrm{m}^2$sec and diffusivity of 7.98${\times}$$10^{-7}$$\textrm{mm}^2$/sec at $20^{\cire}C$, 90%RH water vapor condition.