No abstract

Climate Analysis Seoul (CAS) which provides gridded data relevant for thermal assessment was applied to one of the urban green areas, the Seonjeongneung, in Seoul, Korea. The thermal environment in the Seonjeongneung was evaluated from the CAS simulation for the five heat-wave issued cases during the last five years (2011~2015). The CAS has been improved continuously since it was developed. An updated version with a higher resolution of the CAS simulation domain and an addition of the vegetation information was used in this study. The influence of vegetation in the Seonjeongneung is estimated through the amount of the cold air generation (Q ca ) and air temperature deviation at each grid points, which are calculated by incorporating Geographic Information System (GIS) analysis on the simulation domain and meteorological analysis with the METeorology and atmospheric PHOtochemistry mesoscale MODel (MetPhoMod) in the CAS. The average amount of the cold air generation (Q ca ) at the Seonjeongneung is about 25.5 m 3 m −2 h −1 for the whole cases, and this value is similar to the ones in a forest or a well-wooded region. The average value of the total air temperature deviation (TD) is −2.54 o C at the Seonjeongneung for the five cases. However, this cooling effect of the urban green area disappeared when the region is replaced by high-rise buildings in the CAS simulation. The Q ca drastically decreases to about 1.1 m 3 m −2 h −1 and the average TD shows an increase of 1.14 o C for the same events. This result shows that the vegetation in the Seonjeongneung supposes to keep down temperature during the heat-wave issued day and the average cooling effect of the green region is 3.68 o C quantitatively from the TD difference of the two simulations. The cooling effect represented with the TD difference is larger than 0.3 o C within 200 m distance from the boundary of the Seonjeongneung. Further improvements of the thermodynamical and advection processes above the model surface are required to consider more accurate assessment of the cooling effect for the urban green area.

The electroplating characteristics and deposition layer of a Sn-Bi eutectic alloy applicable to low-temperature soldering were investigated. A methane sulphonate electrolyte was fabricated and the current density was focused in order to achieve an eutectic Sn-Bi composition. The electroplating characteristics, including the polarization curve and deposition thickness with plating time, were also studied. As experimental results, a polarization curve showed a Sn-Bi codeposition occurred under a −0.5 V electropotential. The Bi content in the Sn-Bi deposit decreased with an increasing current density, such as 99.42 wt.% for −10 mA/cm 2 and 42.27 wt.% for −40 mA/cm 2 . The thickness of the electroplated layer increased with the plating time, while a relatively uniform thickness was obtained in a short plating time, such as less than 40 min. The eutectic deposition of Sn-58.2 wt.%Bi was successfully fabricated by plating at −30 mA/cm 2 for 30 min.

Characteristics of precipitation and temperature in Ulleung-do and Dok-do were analyzed with hourly accumulated precipitation and mean temperature data obtained from Automatic Weather System(AWS) for latest four years(2005∼2008).In Ulleung-do, total annual mean precipitation for this period is 1,574.4 mm, which shows larger amount than 1434.2 mm of whole Korean peninsula for latest 10 years(1999～2008) and 1,236.2 mm at Ulleung-do on common years(1971～2000), shows that the trend of precipitation gradually increases during the recent years. This amount is also 1.4 times larger than the total annual mean precipitation of 660.1 mm in Dok-do.Mean precipitation intensity(mm    ) at each time of a day in each month at Ulleung-do represents that the maximum values larger than 3.0 mm    were shown in May and on 0200 LST, whereas these were found in August and 0700 LST with 3.1 mm    in Dok-do. The difference of the precipitation amount and its intensity between Uleung-do and Dok-do is explained by the topological effect came from each covering area, and this fact is also identified from similar comparison of the precipitation characteristics for the islands in West Sea.The annual mean temperature of 14.0 ℃ in Dok-do is 1.2 ℃ higher than that of 12.8 ℃ in Ulleung-do. Trends of monthly mean temperature in both islands are shown to increase for the observed period.

No abstract