• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.2
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• pp.87-93
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• 1995

Strontium titanate single crystal was grown by floating wne method. Growth conditions are as follows; at air atmosphere, rotation rate of upper and lower shafts were 20 - 25 rpm, 15 - 20 rpm respectively and growth rate was 3 mmlhr. As grown crystal was light brown color and transparent. After annealing, color was faded away. Growth direction was [112] direction and it was confirmed that grown crystal has $SrTiO_3$single phase and stoichiometric composition by XRD and EDS. Etch pit pattern was investigated after chemical etching in $350^{\circ}C$, KOH solution for 5 min and dielectric constant was measured at the range of room temperature ~ $350^{\circ}C$ .

• Journal of Environmental Science International
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• v.23 no.12
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• pp.1999-2014
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• 2014

A meteo-tsunami occurred along the coastline of South Korea on 31 March 2007, with an estimated maximum amplitude of 240 cm in Yeonggwang (YG). In this study, we investigated the synoptic weather systems around the Yellow sea including the Bohai Bay and Shandong Peninsula using a weather research and forecast model and weather charts of the surface pressure level, upper pressure level and auxiliary analysis. We found that 4-lows passed through the Yellow sea from the Shandung Peninsula to Korea during 5 days. Moreover, the passage of the cold front and the locally heavy rain with a sudden pressure change may make the resonance response in the near-shore and ocean with a regular time-lag. The sea-level pressure disturbance and absolute vorticity in 500 hPa projected over the Yellow sea was propagated with a similar velocity to the coastline of South Korea at the time that meteo-tsunami occurred.

• Atmosphere
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• v.20 no.3
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• pp.333-341
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• 2010

The stratiform rain fraction is investigated in the tropical boreal winter Madden-Julian oscillation (MJO) and summer intraseasonal oscillation (ISO) using Tropical Rainfall Measuring Mission (TRMM) Precipitation Rader data for the 11-yr period from 1998 to 2008. Composite analysis shows that the MJO/ISO produces larger stratiform rain rate than convective rain rate for nearly all phases following the propagating MJO/ISO deep clouds, with the greatest stratiform rainfall amount when the MJO/ISO center is located over the central-eastern Indian Ocean and the western Pacific. The fraction of the intraseasonally filtered stratiform rainfall compared to total rainfall (i.e., convective plus stratiform rainfall) amounts to 53~56%, which is 13~16% larger than the stratiform rain fraction estimated for the same data on seasonal-to-annual time scales by Schumacher and Houze. This indicates that the MJO/ISO exhibits the organized rainfall process which is characterized by the shallow convection/heating at the incipient phase and the subsequent flare-up of strong deep convection, followed by the development of stratiform clouds at the upper troposphere.

• Ocean and Polar Research
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• v.24 no.3
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• pp.263-266
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• 2002

Gravity waves have been searched for with a new all-sky camera system over Korean Peninsular. The all-sky camera consists of a 37mm/F4.5 Mamiya fisheye lens with a 180 dog field of view, interference filters and a 1024 by 1024 CCD camera. The all-sky camera has been tested near Daejeon city, and moved to Mt. Bohyun where the largest astronomical telescope is operated in Korea. A clear wave pattern was successfully detected in OH filter images over Mt. Bohyun on July 18, 2001, indicating that small scale coherent gravity waves perturbed OH airglow near the mesopause. Other wave features are since then observed with Na 589.8nm and OI 630.0nm filters. Since a Japanese all-sky camera network has already detected traveling ionospheric disturbances (TID) over the northeast-southwest range of Japanese islands, we hope our all-sky camera extends the coverage of the TID's observations to the west direction. We plan to operate our all-sky camera all year around to study seasonal variation of wave activities over the mid-latitude upper atmosphere.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.33-36
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• 2007

We have persistently constructed gridded products of surface wind/wind stress over the world ocean using satellite scatterometer (ERS and Qscat). They are available for users as the Japanese Ocean Flux data sets with Use of Remote sensing Observation (J-OFURO) data together with heat flux components. Recently, a new version data of the Qscat/SeaWinds based on improved algorithm for rain flag and high wind-speed range have been delivered, and allowed us to reconstruct gridded product with higher spatial resolution. These products are validated by comparisons with in-situ measurement data by mooring buoys such as TAO/TRITON, NDBC and the Kuroshio Extension Observation (KEO) buoys, together with numerical weather prediction model products such as the NCEP-1 and 2. Results reveal that the new product has almost the same magnitude in mean difference as the previous version of Qscat product and much smaller than the NCEP-1 and 2. On the other hand, it is slightly larger root-mean-square (RMS) difference than the previous one and NCEPs for the comparison using the KEO buoy data. This may be due to the deficit of high wind speed data in the buoy measurement. The high resolution product, together with sea surface temperature (SST) one, is used to examine a new type of relationship between the lower atmosphere and upper ocean in the Kuroshio Extension region.

• Journal of the korean society of oceanography
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• v.35 no.4
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• pp.161-169
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• 2000

A seasonal circulation in the East China Sea and the Yellow Sea and its possible cause have been studied with CSK data during 1965-1989. Water mass distributions are clear in winter, but not in summer because the upper layer waters are quite influenced by atmosphere. To solve the problem, a water mass analysis by mixing ratio is used for the lower layer waters. The results show that the distribution of Tsushima Warm Current Water expands to the Yellow Sea in winter and retreats to the East China Sea in summer. It means that there is a very slow seasonal circulation between the East China Sea and the Yellow Sea: Tsushima Warm Current Water flows into the Yellow Sea in winter and coastal water flows out of the Yellow Sea in summer. By the circulation, the front between Tsushima Warm Current Water and coastal water moves toward the shelf break in summer so that the flow is faster in the deeper region. The process eventually makes the transport in the Korea Strait increase. The Kuroshio does not seem to influence the process. A possible mechanism of the process is the seasonal change of sea surface slope due to different local effects of surface heating and diluting between the East China Sea and the Yellow Sea.

• Atmosphere
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• v.28 no.2
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• pp.163-174
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• 2018

In order to assimilate MHS satellite data into the convective scale model at KMA, ATOVS data are reprocessed to utilize the original high-resolution data. And then to improve the preprocessing experiments for cloud detection were performed and optimized to convective-scale model. The experiment which is land scattering index technique added to Observational Processing System to remove contaminated data showed the best result. The analysis fields with assimilation of MHS are verified against with ECMWF analysis fields and fit to other observations including Sonde, which shows improved results on relative humidity fields at sensitive level (850-300 hPa). As the relative humidity of upper troposphere increases, the bias and RMSE of geopotential height are decreased. This improved initial field has a very positive effect on the forecast performance of the model. According to improvement of model field, the Equitable Threat Score (ETS) of precipitation prediction of $1{\sim}20mm\;hr^{-1}$ was increased and this impact was maintained for 27 hours during experiment periods.

• Atmosphere
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• v.20 no.2
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• pp.195-210
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• 2010

This study uses mesoscale model WRF to investigate characteristics of wind fields in South Korea, a region with a complex terrain. Hourly wind fields were simulated for one year representing mean characteristics of an 11-year period from year 1998 to year 2008. The simulations were performed on a nested grid from 27 km down to 1 km horizontal resolution. Seasonal variation of wind speed indicates that wind is strongest during the spring and winter seasons. Spatial distribution of mean wind speed shows wind energy potential at its peak in mountainous region of Gangwon-do, the east coast, and Jeju Island. Wind speed peaks at night in mountainous and eastern coastal regions, and in the afternoon inland and in the southwestern coastal region. The simulated wind map was verified with four upper-air sounding observations. Wind speed was shown to have a more pronounced overestimation tendency relative to observation in the winter rather than summer. The results of this wind mapping study help identify locations with the highest wind energy potential in South Korea.

• Atmosphere
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• v.24 no.2
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• pp.189-196
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• 2014

The definition of onset date of Changma is revisited in this study using a quality controlled Ieodo ocean research station data. The Ieodo station has great importance in terms of its southwest location from Korean Peninsula and, hence, makes it possible to predict Changma period in advance with less impact of continents. The onset date of Changma using the Ieodo station data is defined by the time that meridional wind direction changes and maintains from northerly to southerly, and then the zonal wind changes from easterly to westerly after first June. This definition comes from a recognition that the establishment and movement of the western North Pacific subtropical high (WNPSH) cause Changma through southwesterly flow. The onset data of Changma has been determined by large-scale dynamic-thermodynamic characteristics or various meteorological station data. However, even the definition based on circulation data at the Ieodo station has a potential for the improved prediction skill of the onset date of Changma. The differences between before and after Changma, defined as Ieodo station data, are also found in synoptic chart. The convective instability and conspicuous circulations, corresponding low-level southwesterly flow related to WNPSH and strong upper-level zonal wind, are represented during Changma.

• Journal of the Korean Home Economics Association
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• v.40 no.4
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• pp.1-12
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• 2002

This study aimed to examine the needs for the planning of group homes for the elderly with dementia in lower income class, who have more economic burden on the caring the demented aged. The survey was conducted by questionnaires collected from 300 respondents from December 2000 to March 2001. Methods of analysis were frequency distribution, mean and chi-square test. The results of this study were as follows: 1) The respondents perceived that the responsibility to take care of the elderly with dementia belonged to their family, not to society or the government, and the sons and daughters had to share the burden placed on care-givers. 2) The awareness of group homes for dementia was relatively low. 3) The respondents' needs for the group homes with dementia could be summarized as follows; small scale plan with homelike atmosphere, a total of 6-8 residents, structural type of detached house or three-storied town house, 2-3 persons per individual room, and management system by non-profit organization or the government. There were no big differences between the respondents of this study and upper and middle class studies conducted by other research, except for some details. Referring to results of this study, it is asserted that group homes for the elderly with dementia would be embraced throughout the country if poetical assistance combined with economic support were provided.