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        검색결과 52

        42.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        This study focused on comparing the meteorological conditions in the Atmospheric Boundary Layer (ABL) on high-event days and non-event days in the Seoul Metropolitan Area (SMA). We utilized observed PM10 and meteorological variables at the surface as well as at the upper heights. The results showed that high-event days were consistently associated with lower wind speed, whereas wind direction showed no particular difference between high-event and non-event days with frequent westerlies and northwesterlies for both cases. During high-event days, the temperature was much warmer than the monthly normal values with a sharp increasing trend, and Relative Humidity (RH) was higher than the monthly normal, especially on high-event days in February. During high-event days in spring, a double inversion layer was present at surface and upper heights. This indicates that stability in the multi-layer is an important indicator of higher PM10 concentrations. Net radiation in spring and winter is also closely associated with higher PM10 concentrations. Strong net radiation resulted in large sensible heat, which in turn facilitated a deeper mixing height with diluted PM10 concentrations; in contrast, PM10 concentrations were higher when sensible heat in spring and winter was very low. We also confirmed that convective and friction velocity was higher on non-event days than on high-event days, and this was especially obvious in spring and winter. This indicated that thermal turbulence was dominant in spring, whereas in winter, mechanical turbulence was dominant over the SMA.
        43.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Many recent satellites have mission periods longer than 10 years; thus, satellite-based local space weather monitoring is becoming more important than ever. This article describes the instruments and data applications of the Korea Space wEather Monitor (KSEM), which is a space weather payload of the GeoKompsat-2A (GK-2A) geostationary satellite. The KSEM payload consists of energetic particle detectors, magnetometers, and a satellite charging monitor. KSEM will provide accurate measurements of the energetic particle flux and three-axis magnetic field, which are the most essential elements of space weather events, and use sensors and external data such as GOES and DSCOVR to provide five essential space weather products. The longitude of GK-2A is 128.2° E, while those of the GOES satellite series are 75° W and 135° W. Multi-satellite measurements of a wide distribution of geostationary equatorial orbits by KSEM/GK-2A and other satellites will enable the development, improvement, and verification of new space weather forecasting models. KSEM employs a service-oriented magnetometer designed by ESA to reduce magnetic noise from the satellite in real time with a very short boom (1 m), which demonstrates that a satellite-based magnetometer can be made simpler and more convenient without losing any performance.
        44.
        2017.08 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to analyze the muscle activity in the right forearm and shoulderwhile doing the sowing activity by muscle type and work section, and to find the possibility of the utilization of sowing as a muscle exercise and rehabilitative activity based on the results of the analysis. The results showed that the activity of 7 muscles including the upper trapezius near the neck, the upper trapezius near the shoulder, the middle deltoid, the biceps brachii, the triceps brachii, the brachioradialis, and the flexor carpi ulnaris were significantly higher than the stable state. In addition, the muscle activity in the sections of mixing the soil, filling the tray with the soil, sowing, writing the label, and watering was significantly higher than the stable state. In particular, the muscle activity of the biceps brachii and the triceps brachii was statistically significantly high in the section of filling the tray with the soil, which indicates that the task of filling the tray with the soil can be utilized as an exercise to activate the biceps brachii and the triceps brachii. In addition, the muscle activity of the brachioradialis was significantly high in all the work sections, which indicates that the sowing process can be utilized to exercise the brachioradialis in particular. These results can be used as the basic data about the activated muscle types and degrees throughout the sowing process. These results can be also used to induce the activation of specific muscles, and the overall exercise and rehabilitation of the forearms.
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