• Korean Journal of Environmental Agriculture
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• v.18 no.3
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• pp.215-220
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• 1999

Behaviour of a fungicide $^{14}C-propiconazole$ was investigated in a rice plant grown-lysimeter soil. The lysimeter was composed of soil cores of silty clay. $Propiconazole(Tilt\;250^R\;EC)$ plus $^{14}C-labeled$ propiconazole was applied on the surface of lysimeter soil at a rate of 0.12kg/10a after rice transplanting. The application was done consecutively for two years. The behaviours of propiconazole in the lysimeter soil were investigated by measuring the amounts of $^{14}C-leachate$, $^{14}CO_2$, the residues distributed in each soil segment and taken up by rice plants. The relative amounts of $^{14}C$ leached from the lysimeter were the background level of the applied $^{14}C$ throughout expeiment. The amounts of $^{14}CO_2$ evolved from the lysimeter were 5.7 and 7.8% of the original $^{14}C$ in the 1st and 2nd treatment, respectively. The amounts of volatile substances soil were the background level throughout experiment, which indicated that propiconazole was stable chemically in the experimental condition. The $^{14}C-activities$ absorbed and translocated into rice plants were 3.7 and 7.6% in 1st and 2nd treatment, respectively. The $^{14}C-activities$ in the soil layer of the lysimeter was distributed mainly in the depth of 0 to 20cm, which suggested propiconazole did not have the risk of groundwater contamination.

• Journal of the Korean Ceramic Society
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• v.38 no.9
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• pp.853-859
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• 2001

The dispersion stability of nano $Y_2O_3-CeO_2$ system was investigated using colloid surface chemistry. Green body of $Y_2O_3$ doped $CeO_2$ was prepared by slip casting in and aqueous system. The dispersion stability of suspension between powders and organic additive was accomplished through electrokinetic behavior of suspension, which was done by ESA apparatus. The dynamic mobility of particles was enhanced when the anionic dispersant of the amount of 1wt% was added. The dissolution of $Y^{3+}$ ion in suspension occurred in the acidic region so that pH value in slurries did not move to below 7.0. In the $CeO_2-Y_2O_3$ system, optimal preparation of suspension was made after adding the anionic dispersant as the amount of 1wt% and pH value of 11.0, and then slip-cast and sintered at 1400$^{\circ}$C, 2 hrs. It appeared relative density of >98% and homogeneous distribution of Y element in depth direction as well as in the microstructure of surface.

• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.209-223
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• 2016

We present analyses of ~1250 variable sources identified in a 20 square degree field toward NGC 2784 by the KMTNet Supernova Program. We categorize the variable sources into three groups based on their B-band variability. The first group consists of 31 high variability sources with their B-band RMS variability greater than 0.3 magnitudes. The second group of medium variability contains 265 sources with RMS variability between 0.05 and 0.3 magnitudes. The remaining 951 sources belong to the third group of low variability with an RMS variability smaller than 0.05 magnitudes. Of the entire ~1250 sources, 4 clearly show periods of variability greater than 100 days, while the rest have periods shorter than ~51 days or no reliable periods. The majority of the sources show either rather irregular variability or short periods faster than 2 days. Most of the sources with reliable period determination between 2 and 51 days belong to the low-variability group, although a few belong to the medium-variability group. All the variable sources with periods longer than 35 days appear to be very red with B - V > 1.5 and V - I > 2.1 magnitudes. We classify candidates of 51 Cepheids, 17 semi-regular variables, 3 Mira types, 2 RV(B) Tauri stars, 26 eclipsing binary systems and 1 active galactic nucleus. The majority of long-term variables in our sample belong to either Mira or semi-regular types, indicating that long-term variability may be more prominent in post-main sequence phases of late-type stars. The depth of the eclipsing dips of the 26 candidates for eclipsing binaries is equivalent to ~0.61 as the average relative size of the two stars in the binary system. Our results illustrate the power of the KMTNet Supernova Program for future studies of variable objects.

• Journal of Digital Convergence
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• v.9 no.5
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• pp.235-251
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• 2011

Despite the increasing importance of information technology in firms, the extent to which IT governance are established varies widely across the firms. To perform desirably the role of IS needed in most companies, high level of IT governance and the effective management should precede. However, the impacts of such activities and management on the IT governance have not been empirically examined in depth until now. Thus, building on the theory of governance and the institutionalization, the research model and the hypotheses of the study were formed and then empirically tested. The study used a survey of senior IT managers from 108 firms in order to examine hypothesized relationship among the following constructs: strategic alignment, IT governance committee, IT planning, EA, PMO, SLM, IT compliance, incident management, IS effectiveness, visibility, and corporate performance. A structural equation model is developed by using LISREL to assess the relative effects and interrelationship among these constructs. The results show that strategic alignment has positive influence on IT governance committee and IT planning. IT governance committee, IT planning, SLM, incident management from IT governance activities have positive effects on IS effectiveness, whereas IT compliance has a negative effect on IS effectiveness. Visibility is positively influenced by IT planning, EA, SLM. IT compliance, and both IS effectiveness and visibility have positive effects on corporate performance.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.811-824
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• 2005

The ADCP is an instrument based on Doppler effect, which measures discharge of a river in a short time while crossing it. In this study we aim to make a comparison of the discharge results from a moving-vessel ADCP with those measured by velocity-area method at the same cross-section, and to investigate the characteristics of velocity and discharge data using ADCP. Bathymetry measured by ADCP almost coincides with that by direct depth measurements. Because velocity data from ADCP are essentially instantaneous, individual velocity profiles obtained by ADCP are rather different from time-averaged velocity profiles. But spatially averaged velocity profiles of the individual ADCP data near the comparable verticals have similar vertical velocity pattern with the time-averaged ones. The average velocity profile from repeatedly crossed data is also similar with the time-averaged one. In case of the velocity distribution, individual and spatially averaged data for the sub-width of mid-section method Have good agreement with those by velocity-area method. Discharge data determined by averaging several ADCP measurement transects have $0.1\%{\~}9.3\%$ of difference with those from velocity-area method, and as the number of measurement increases, the relative difference to the velocity-area method decreases.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.8-18
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• 1999

The degradation of a fungicide, $^{14}C$-propiconazole, in sterile and nonsterile soil from different depths was investigated. $^{14}C$-propiconazole plus propiconazole standard was treated on the soil at the rate of 7.55 mg/kg and the soil was incubated at $25^{\circ}C$ for 20 weeks. The amounts of $^{14}CO_{2}$ solvent extractable and non-extractable $^{14}C$, and degradation products of $^{14}C$-propiconazole were investigated during incubation time. The relative amounts of $^{14}CO_{2}$ released in the sterile and nonsterile soils were ranging from 0.7 to 1.3% and from 4.8 to 7.6% of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues in the sterile and nonsterile soils were ranging from 11.2 to 22.1% and from 22.2 to 41.9% of of applied $^{14}C$, repectively. The amounts of solvent non-extractable residues were increased with incubation time and most of $^{14}C$ were detected in the humin fraction. The hydroxylated and ketone compound were confirmed as a degradation products of propiconazole by GC/MS analysis, whereas parent compound was detected in sterile soil, which suggested that propiconazole was not degraded biologically under the sterile soil. From the results of volatilization, mineralization and degradation of propiconazole, propiconazole was stable chemically and bilogically in soil.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.340-346
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• 2002

Capacitor material utilized in the downsizing passive devices and integration of passive devices requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. common capacitor materials, $Al_2O_3$, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$, TaN and et al., used until recently have reached their physical limits in their application to integration of passive devices. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism. This study presents the dielectric properties $Ta_2O_{5}$ MIM capacitor structure Processed by $O_2$ RTA oxidation. X-ray diffraction patterns showed the existence of amorphous phase in $600^{\circ}C$ annealing under the $O_2$ RTA and the formation of preferentially oriented-$Ta_2O_{5}$ in 650, $700^{\circ}C$ annealing and the AES depth profile showed $O_2$ RTA oxidation effect gives rise to the $O_2$ deficientd into the new layer. The leakage current density respectively, at 3~1l$\times$$10_{-2}$(kV/cm) were $10_{-3}$~$10_{-6}$(A/$\textrm{cm}^2$). In addition, behavior is stable irrespective of applied electric field. the frequency vs capacitance characteristic enhanced stability more then $Ta_2O_{5}$ thin films obtained by $O_2$ reactive sputtering. The capacitance vs voltage measurement that, Vfb(flat-band voltage) was increase dependance on the $O_2$ RTA oxidation temperature.

• Korean Journal of Agricultural Science
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• v.10 no.1
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• pp.118-128
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• 1983

Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.

• Journal of the Korean Geotechnical Society
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• v.32 no.9
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• pp.51-62
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• 2016

Parametric studies for various site conditions by using 3d numerical model were carried out in order to estimate dynamic behavior of soil-pile-structure system in dry soil deposits. Proposed model was analyzed in time domain using FLAC3D which is commercial finite difference code to properly simulate nonlinear response of soil under strong earthquake. Mohr-Coulomb criterion was adopted as soil constitutive model. Soil nonlinearity was considered by adopting the hysteretic damping model, and an interface model which can simulate separation and slip between soil and pile was adopted. Simplified continuum modeling was used as boundary condition to reduce analysis time. Also, initial shear modulus and yield depth were appropriately determined for accurate simulation of system's nonlinear behavior. Parametric study was performed by varying weight of superstructure, pile length, pile head fixity, soil relative density with proposed numerical model. From the results of parametric study, it is identified that inertial force induced by superstructure is dominant on dynamic behavior of soil-pile-structure system and effect of kinematic force induced by soil movement was relatively small. Difference in dynamic behavior according to the pile length and pile head fixity was also numerically investigated.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.61-69
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• 2004

Building stones are used mainly as a material for making decoration and sculpture, and consequently they must have predominant physical properties extensively. Among various physical properties, the coefficient of pore dominates the usefulness of building stones, so the plans were made for establishing the quality classification of building stones with respect to the nature of pore. For this study, bore-hole core samples according to the depth of the biotite granites and the granitic gneiss were applicated. From the related chart between porosity and absorption ratio, Mungyeong granitic gneiss($Gn_1$) shows the widest phase of distribution in the range of measurement values, and the values decrease in the order of Pocheon granite($Gr_2$) and Mungyeong granite($Gr_1$) in the range. The strength of each rock mass varies with the degree of alteration. Also in correlation between compressive strength and tensile strength, the range of measurement values decrease in the order of $Gn_1$, $Gr_2$and $Gr_1$. Porosity is adopted as a representative physical property for establishing the quality classification of building stones, and then relative evaluation was made with regard to various physical properties. From the related chart between porosity(n)-specific gravity(G), absorption ratio(Ab), compressive strength(${\sigma}_{c}$), tensile strength(${\sigma}_{t}$), shore hardness(Hs) and Young's modulus($E_{t}$), standard of each grade is established.