• Journal of The Korean Astronomical Society
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• v.38 no.4
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• pp.437-443
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• 2005

The Solar Radio Burst Locator (SRBL) is a spectrometer that can observe solar microwave bursts over a wide band (0.1-18 GHz) as well as detect the burst locations without interferometry or mechanical scanning. Its prototype has been operated at Owens Valley Radio Observatory (OVRO) since 1998. In this study, we have evaluated the capability of the SRBL system in flux and radio burst location measurements. For this, we consider 130 microwave bursts from 2000 to 2002. The SRBL radio fluxes of 53 events were compared with the fluxes from USAF/RSTN and the burst locations of 25 events were compared with the optical flare locations. From this study, we found: (1) there is a relatively good correlation (r = 0.9) between SRBL flux and RSTN flux; (2) the mean location error is about 8.4 arcmin and the location error (4.7 arcmin) of single source events is much smaller than that (14.9 arcmin) of multiple source events; (3) the minimum location error usually occurred just after the starting time of burst, mostly within 10 seconds; (4) there is a possible anti-correlation (r = -0.4) between the pointing error of SRBL antenna and the location error. The anti-correlation becomes more evident (r=-0.9) for 6 strong single source events associated with X-class flares. Our results show that the flux measurement of SRBL is consistent with that of RSTN, and the mean location error of SRBL is estimated to be about 5 arcmin for single source events.

• Fire Science and Engineering
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• v.21 no.3
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• pp.78-83
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• 2007

Diesel, a kind of petroleum, which is used in vehicles, vessels, boilers etc causes great damage when a fire happens, because it has higher caloric value than gasoline or kerosene has at burning. Therefore, pool fire experiment was carried using diesel which is sold on the gas station and radiation heat flux that occurs from flame and inner temperature of flame at burning was estimated. The maximum instantaneous flame temperature of diesel was more than $900^{\circ}C$, and the average of maximum flame temperature was $800^{\circ}C$ which occurred at 0.5 H/D distance from the surface of inflammable liquid, the distance has more long that has the lower the temperature of flame. In case of radiation heat flux, it grew to vary according to the size and amount of sample. When the size of a container for experiment was 0.5 m and sample layer was 13 mm and 20 mm, the radiant heat was 92.29 kW and 117.43 kW each. When the container was 1.0 m, it was 364.35 kW and 405.88 kW each.

• Progress in Superconductivity and Cryogenics
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• v.17 no.1
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• pp.21-24
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• 2015

New results of dependence of magnetic field, trapped by a stack of HTS tapes, on amount of tapes in a stack are reported. Commercial GdBCO tape 12 mm width and without Cu layer was used for the research. Tape was divided in square pieces $12{\times}12mm^2$ from which stacks were formed. Filling factor of the tape was about 1.4%. Measurements were carried out for stacks with height from 5 to 250 pieces and at wide temperature range from liquid helium to liquid nitrogen. Both FC (field cooling) and ZFC (zero field cooling) cooling methods were used in the research. These two methods show matching results with good accuracy. As a result dependences of trapped magnetic flux on amount of tapes for different temperatures were received. Research shows, that with increasing height of the stack trapped magnetic field value reach saturation at about 60 tapes in a stack for low temperatures. From 60 to 100 tapes increase of magnet flux is only 5%. Thus increase amount of tapes in a stack is not profitable. Also investigation of trapped magnet field relaxation was carried out. Relaxation speed decreases with increasing amount of elements. It means that the higher the stack is, the longer trapped flux will be held in cause of the same temperature.

• Atmosphere
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• v.27 no.2
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• pp.163-175
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• 2017

The global terrestrial ecosystems have shown a large spatial variability in recent decades and represented a carbon sink pattern at mid-to-high latitude in Northern Hemisphere. However, there are many uncertainties in magnitude and spatial distribution of terrestrial carbon fluxes due to the effect of climate factors. So, it needs to accurately understand the spatio-temporal variations on carbon exchange flux with climate. This study focused on the effects of climate factors, .i.e. temperature, precipitation, and solar radiation, to terrestrial biosphere carbon flux. We used the terrestrial carbon flux that is simulated by a CarbonTracker, which performs data assimilation of global atmospheric $CO_2$ mole fraction measurements. We demonstrated significant interactions between Net Ecosystem Production (NEP) and climate factors by using the partial correlation analysis. NEP showed positive correlation with temperature at mid-to-high latitude in Northern Hemisphere but showed negative correlation pattern at $0-30^{\circ}N$. Also, NEP represented mostly negative correlation with precipitation at $60^{\circ}S-30^{\circ}N$. Solar radiation affected NEP positively at all latitudes and percentage of positive correlation at tropical regions was relatively lower than other latitudes. Spring and summer warming had potentially positive effect on NEP in Northern Hemisphere. On the other hand as increasing the temperature in autumn, NEP was largely reduced in most northern terrestrial ecosystems. The NEP variability that depends on climate factors also differently represented with the type of vegetation. Especially in crop regions, land carbon sinks had positive correlation with temperature but showed negative correlation with precipitation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.990-994
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• 2005

MBE growth conditions such as growth temperature, flux ration and growth rate for II-VI compound semiconductor growth has been studied. The growth temperature, flux ration and growth rate were tentatively controlled to 290$^{\circ}C$, 2, and 0.6 ${\mu}m$/h, respectively. From AFM result, relatively rough surface (RMS ${\sim}$ 2.9 nm) was observed. It was regarded as an indication of low growth temperature and high growth rate. XRD measurement shows that the film is relaxed, also the series of XRD measurements of different diffraction planes such as (002), (004), (115), (006) diffractions were performed to calculate the dislocation density in the film. The calculated dislocation density was found to be 8.30${\times}10^8$ dis/cm$^2$ which is compatible to the previous results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.562-570
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• 2009

An Experimental study was conducted on the flow characteristics and interference heating caused by a two-dimensional object protruding from a flat plate using a blow-down type of hypersonic wind tunnel. Inflow condition was a free-stream Mach number of 7.0 and a unit Reynolds number of $2.0{\times}10^6/m$. Experimental conditions were varied with three heights of protuberance for two flat plate models which have different lengths. Experimental data were obtained from Schlieren visualization images and heat flux measurements. Also, this paper suggests hypersonic experimental techniques such as boundary-layer detection method in detail. A Large separation region was observed in front of the protuberance and that region was very sensitive to the height of protuberance and the length of the flat plate. For only the highest protuberance, a severe jump of heat flux was observed at the top station among the measuring points. Measured heat flux is large when the height of protuberance is large and the length of flat plate is long.

• Journal of the korean society of oceanography
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• v.31 no.2
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• pp.55-63
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• 1996

Distribution of suspended particulate matter, dissolved oxygen and major inorganic nutrients along a meridional section ($126^{\circ}$ 33' E) in the Cheju Strait is described along with the hydrographic and current data obtained during April 25-27, 1995. The current measurements was conducted using a vessel-mounted Acoustic Doppler Current Profiler (ADCP). Repeated coverage along an ADCP transect during 25 hours allows to calculate the daily mean along- and cross-strait currents. Measured material concentrations and the mean current speed were used to estimate the flux density (cencentration times current speed) of materials. Two types of depth distibution of flux densities were observed. for nitrate and suspended particulate matter, the depth distribution pattern of materials determines those of flux densities. However, flow patterns determine those of flux densities for dissolved oxygen, phosphate and silicic acid. The total along-strait water volume transport is about 0.3 Sv (1Sv $10^{6}$ $m^{3}/s^{-1}$). The total along-strait material transports are estimated to be 3.1 $${\times} $10^{5}$ $g/s^{-1},$ 2.4 ${\times}$ $10^{6}\;g/s^{-1},$ 7.I ${\times}$ $10^{2}\;mol/s^{-1},$ 3.I ${\times}$ $10\;mol/s^{-1},$ 1.7 ${\times}$ $10^{3}\;mol/s^{-1}$ for suspended particulate matter, dissolved oxygen, nitrate ion, silicic acid and phosphate ion, respectively.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.572-577
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• 2001

The feasibility of skin penetration was studied for aspalatone (AM, acetylsalicylic acid maltol ester), a novel antithrombotic agent. In this studys hairless mouse dorsal skins were used as a model to select composition of vehicle and AM. Based on measurements of solubility and partition coefficient, the concentration of PC that showed the highest flux for AM across the hairless mouse skin was found to be 40%. The cumulative amount permeated at 48 h, however, appear inadequate, even when the PC concentration was employed. To identify a suitable absorption enhancer and its optimal concentration for AM, a number of absorption enhancers and a variety of concentration were screened for the increase in transdermal flux of AM. Amongst these, linoleic acid (LOA) at the concentration of 5% was found to have the largest enhancement factor (i.e., 132). However, a further increase in AM flux was not found in the fatty acid concentration greater than 5%, indicating the enhancement effect is in a bell-shaped currie. In a study of the effect of AM concentration on the permeation, there was no difference in the permeation rate between 0.5 and 1% for AM, below its saturated concentration. At the donor concentration of 2%, over the saturated condition, the flux of AM was markedly increased. A considerable degradation of AM was found during permeation studies, and the extent was correlated with protein concentrations in the epidermal and serosal extracts, and skin homogenates. In rat dorsal skins, the protein concentration decreased in the rank order of skin homogenate > serosal extract > epidermal extract. Estimated first order degradation rate constants were $6.15{\pm}0.14,{\;}0.57{\pm}0.02{\;}and{\;}0.011{\pm}{\;}0.004{\;}h^{-1}$ for skin homogenate, serosal extract and epidermal extract, respectively. Therefore, it appeared that AM was hydrolyzed to some extent into salicylmaltol by esterases in the dermal and subcutaneous tissues of skin. taken together, our data indicated that transdermal delivery of AM is feasible when the combination of PC and LOA is used as a vehicle. However, since AM is not metabolically stable, acceptable degradation inhibitors may be nervessary to fully realize the transdermal delivery of the drug.

• Fire Science and Engineering
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• v.33 no.2
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• pp.39-46
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• 2019

This study assessed the measurement errors and improvement of the spatial resolution through miniaturization of the plate thermometer used to measure the heat flux in a fire environment. As a result, the heat loss to the side of plate thermometer was found to have a significant influence on the measurement error through analysis of the measurement values according to the thickness and density change to the insulation installed on the back side of the plate. Based on the existing 10 cm square shape, it was also confirmed that the 3 cm size plate thermometer could measure the heat flux with satisfactory accuracy through miniaturization. These results are expected to be useful for accurate measurements of the heat flux at local locations in a fire environment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.340-345
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• 2020

In this study, we developed the quality control and assurance method of measurement data of SPAR (Soil-Plant-Atmosphere-Research) system, a climate change research facility, for the first time. It was found that the precise processing of CO2 flux data among many observations were sig nificantly important to increase the accuracy of canopy photosynthesis measurements in the SPAR system. The collected raw CO2 flux data should first be removed error and missing data and then replaced with estimated data according to photosynthetic lig ht response curve model. Comparing the correlation between cumulative net assimilation and soybean biomass, the quality control and assurance of the raw CO2 flux data showed an improved effect on canopy photosynthesis evaluation by increasing the coefficient of determination (R2) and lowering the root mean square error (RMSE). These data processing methods are expected to be usefully applied to the development of crop growth model using SPAR system.