• Corrosion Science and Technology
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• v.10 no.3
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• pp.87-94
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• 2011

The typical corrosion prevention method inside the steel upper box girder in a suspension bridge involves the use of paints. However, in an effort to reduce environmental impact and cost, the suspension portion of the Yeongjong Bridge, Korea utilizes dehumidification systems to control humidity and prevent corrosion inside its box girder. Maintaining a uniform humidity distribution at the proper level inside the box girder is critical to the successful corrosion control. In this study, the humidity and the resultant atmospheric corrosivity inside the box girder of the Yeongjong Bridge was monitored. The corrosion rate of the steel inside the box girder was obtained using thin-film electrical resistance (TFER) corrosion sensors. Time-of-wetness (TOW) measurements and the deposition rates of atmospheric pollutants such as $Cl^{-}$ and $SO_{x}$ were also obtained. Classification of the atmospheric corrosivity inside the box girder was evaluated according to ISO 9223. As a result, no corrosion was found in the upper box girder, indicating that the dehumidification system used in the Yeongjong Bridge is an effective corrosion control method.

• Journal of the Semiconductor & Display Technology
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• v.8 no.2
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• pp.15-21
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• 2009

Atmospheric pressure plasma equipment was successfully applied to the flip chip BGA manufacturing process to improve the uniformity of flux printing process. The problem was characterized as shrinkage of the printed flux layer due to insufficient surface energy of the flip chip BGA substrate. To improve the hydrophilic characteristics of the flip chip BGA substrate, remote DBD type atmospheric pressure plasma equipment was developed and adapted to the flux print process. The equipment enhanced the surface energy of the substrate to reasonable level and made the flux be distributed over the entire flip chip BGA substrate uniformly. This research was the first adaptation of the atmospheric pressure plasma equipment to the flip chip BGA manufacturing process and a lot of possible applications are supposed to be extended to other PCB manufacturing processes such as organic cleaning, etc.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.1
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• pp.19-27
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• 1999

This paper is to estimate the long and short term variations of mean sea level in Korean coastal waters by identifying interrelations among the mean sea level, atmospheric pressure and air temperature along the coast. For this, long-term tidal data observed at tidal and weather observation stations were brought into a statistical analysis. It was noted that, in a general sense, an inverse relationship exists between the sea level and the atmospheric pressure and a positive relationship between the sea level and air temperature, respectively. The maximum difference of monthly mean sea level was in the range of 21 to 25 cm at the eastern and southeastern coasts, meanwhile more than 30 cm being in both in southern and western coasts. It was also noted that mean sea level continues to rise in a long-term basis. Long-term variation of mean sea level trends to rise 0.10 ∼ 0.44 cm per year for each region. However, the long-term variation of mean sea level in the isolated islands shows a different trend, Ullngdo being 0.41 cm fall per year and Chejudo being 0.44 cm rise per year.

• Journal of Integrative Natural Science
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• v.4 no.1
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• pp.44-57
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• 2011

In general, heavy rainfall in Korea is mostly associated with inflow of 850hPa low-level jet. It transports abundant heat and moisture flux to the Changma front. In this study, synoptic characteristics of heavy rainfall in Korea from a case study is examined by classifying heavy rainfall cases with synoptic patterns, in particular distribution of upper- and low-level jets, western North Pacific high, and moisture flux. The surface and upper-level weather charts including auxiliary analysis chart and radar and satellite images obtained from the Korea Meteorological Administration, and 500hPa geopotential heights from NCEP/NCAR are used and then KLAPS is applied to understand the local atmospheric structure associated with heavy rainfall. Results show that maximum frequency in 60 heavy rainfall cases with more than 150mm/day appears in the Changma type of 43 cases (a proportion in relation to a whole is 52%) including the combined Changma types with typhoon and cyclone. As indicated in previous studies, most heavy rainfall cases are related to inflow of low-level jet. In addition, synoptic characteristics based on the analyses of weather charts, radar and satellite images, and KLAPS in heavy rainfall case of 12 July, 2009 reveal that the atmospheric vertical structure in particular equivalent potential temperature favorable for effective inflow of warm and moist southwesterly into the Changma front is linked to large potential instability and the strong convergence accompanied with low-level jet around Suwon contributes to atmospheric upsliding along the Changma front, producing heavy rainfall.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.3
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• pp.175-182
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• 1994

Backward trajectory analysis was carried out for 41 cases at 850 hPa level and 47 cases at 700 hPa level during the period from May 1992 to August 1993 in order to understand the impact of long-range transported pollutants from the neighboring countries on the distribution pattern of acid rain in Korea. The occurrence frequencies of acid rain were also investigated using the rainwater data observed at 5 stations in the central part of Korea, Kangwha, Seoul, Yangpyong, Hongchon, and Inje. The trajectory analysis showed that westerlies were dominant on 700 hPa level and southwesterlies on 850 hPa level in Korea. The pH values were also often lower when the trajectory was stagnant in the upper air over Korea. However, pH values were normally higher in all directions of flows during the Yellow Sand Period due to the increase of Positive ion components such as $Ca^{+2}$. The pH values were also normally higher when air flows from north or northeast.

• Atmosphere
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• v.19 no.1
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• pp.67-78
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• 2009

A strong negative correlation has been detected between the North Pacific Oscillation Index (NPI) and the Effective Drought Index (EDI) in May over Korea. In May of positive NPI year, anomalous patterns caused a drought in Korea as follows: the anomalous south-low, north-high low-level pressure patterns in the northeast and southeast of Korea have strengthened the anomalous northerlies to Korea. In addition, these anomalous northerlies have prevented western North Pacific (WNP) high from moving northward. As a result, anomalous descending flows have strengthened in the mid-latitude region in East Asia. In the WNP, the anomalous south-high, north-low sea surface temperature (SST) has been widely distributed, which has strengthened anomalous south-low, north-high low-level pressure patterns. These anomalous characteristics of pressure and SST patterns observed in May of positive NPI years have already been detected in previous winter (December-February) and early spring (March, April). In addition, the anomalous negative sea ice concentration in the North Pacific during two seasons has strengthened the anomalous anticyclonic circulation in the same region and in turn made a contribution to formation of anomalous south-low, north-high pressure patterns in May.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.6
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• pp.451-461
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• 1997

The soil NO flux measurements in Korea were made from 17 May 1997 to 16 June 1997 on grass land at Kunsan National University in southwestern Korea by using flow-through chamber technique. The experiment was conducted in an effort to determine the role of natural emissions of NO on rural atmospheric photochemistry, and to understand the soil NO emission mechanism with respect to soil parameters. Soil NO fluxes were measured every minutes and averaged in every 15 minutes as well as soil temperature. Soil samples were analyzed for $NO_3^-, NH_4^+$, and moisture in soil. Soil nitrate was not detected in most times, and total N-containing was limited in site soils. There was a optimum range of soil moisture and temperature for soil NO flux. The overall average of soil NO emission rates were found to be 1.30 $\pm 0.92 ngNm^{-2}s^{-1}$ (n=1219), and ranged from 0.01 ngNm^{-2}s^{-1}$ to 5.62 ngNm^{-2}s^{-1}$. Diurnal variation of soil NO emission was typical, which was in higher level during daytime, and was in lower level over the night. NO flux showed a strong soil temperature dependence $(r^2=0.78)$, but not with soil moisture and soil N-containing during this experimental period; NO fluxes increased exponentially as soil temperature increased. In order to assure the relevant relationship between soil NO flux and the soil parameters, long-term soil flux measurement on different types of land use should be planned and conducted continuously.

• Atmosphere
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• v.23 no.3
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• pp.357-365
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• 2013

A public-academia cooperative research system is suggested to improve the level of national research on atmospheric science and to enable the National Institute of Meteorological Research (NIMR) to meet its overloaded demand for research and results. As a practical example of cooperative research the CIRES case was reviewed. CIRES, the Cooperative Institute for Research in Environmental Sciences, located at the University of Colorado Boulder, is one of NOAA's 18 cooperative research centers located at universities across the U.S. NOAA, the National Oceanic and Atmospheric Administration, as a part of government, gives clear guideline for research topics and supplies research funds to research centers and audits their research processes and accomplishments. NOAA Boulder Laboratories, as a large, well-established government research center managed by government scientists, supplies depth of experiences and major research infra-structure to CIRES. CIRES pursues innovative and challenging research with their younger and brand-new researchers who are university employees. This cooperative work between government research organizations and the university produces high level research efficiently. Not only does Boulder have a beautiful natural setting where researchers live and work but also the city is a home to many scientific agencies and research facilities. This robust scientific network provides rich opportunities for CIRES researchers to collaborate with others in their scientific fields.

• Journal of The Korean Association For Science Education
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• v.33 no.6
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• pp.1219-1236
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• 2013

The purpose of this study was to investigate the association between subject matter knowledge (SMK) and pedagogical content knowledge (PCK) for science teachers. To this end, a total of 26 secondary Earth science teachers participated in this study and a concept diagnostic questionnaire and a lesson planning task of atmospheric pressure were devised to give an indication of participating teachers' SMK and PCK, respectively. The results of this study are summarized as follows: First, participating teachers showed a variety of SMK levels about atmospheric pressure. Second, teachers at high level of SMK focused on 'supplementary' and 'fundamental' curriculum contents for in-depth conceptual understanding, but teachers at low level of SMK, on the contrary, stressed 'applicative' curriculum contents. Third, teachers at high level of SMK grasped students' misconceptions and difficulties in learning atmospheric pressure far more concretely than teachers at low level of SMK. Lastly, teachers at high level of SMK showed a tendency to use learner-centered instructional strategy by utilizing students' prior knowledge, but teachers at low level of SMK were inclined toward teacher-directed concept explanation. Based on this study, some implications for effective science teacher preparation programs were also discussed.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.260-267
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• 2016

Background: This study analyzes the differences in the annual averaged atmospheric dispersion factor and ground deposition factor produced using two classification methods of atmospheric stability, which are based on a vertical temperature difference and the standard deviation of horizontal wind direction fluctuation. Materials and Methods: Daedeok and Wolsong nuclear sites were chosen for an assessment, and the meteorological data at 10 m were applied to the evaluation of atmospheric stability. The XOQDOQ software program was used to calculate atmospheric dispersion factors and ground deposition factors. The calculated distances were chosen at 400 m, 800 m, 1,200 m, 1,600 m, 2,400 m, and 3,200 m away from the radioactive material release points. Results and Discussion: All of the atmospheric dispersion factors generated using the atmospheric stability based on the vertical temperature difference were shown to be higher than those from the standard deviation of horizontal wind direction fluctuation. On the other hand, the ground deposition factors were shown to be same regardless of the classification method, as they were based on the graph obtained from empirical data presented in the Nuclear Regulatory Commission's Regulatory Guide 1.111, which is unrelated to the atmospheric stability for the ground level release. Conclusion: These results are based on the meteorological data collected over the course of one year at the specified sites; however, the classification method of atmospheric stability using the vertical temperature difference is expected to be more conservative.