• Asian Journal of Atmospheric Environment
• /
• 제11권4호
• /
• pp.235-253
• /
• 2017

This study was conducted for analyzing the contribution factors on ozone concentrations and its long term trends in each major city and province in Korea through several statistical methods such as simple linear regression, generalized linear model, KZ-filer, correlation matrix, Kringing method, and cluster analysis. The overall ozone levels in South Korea have been consistently increasing over the past 10 years. The ozone concentrations in Seoul, the biggest city in Korea, are the lowest in all areas with the highest increasing ratio for $95^{th}%$ ozone. It is thought that the active photochemical reaction could affect the higher ozone concentration increase. On the other hand, the ozone concentrations in Jeju are the highest in Korea with the highest increasing ratio for $5^{th}%$, $33^{th}%$, and $50^{th}%$ ozone. It is also thought that the weak $NO_x$ titration could be the reason of higher ozone concentrations in Jeju. In case of Jeju, transport related factors is the major factor affecting the ozone trend. Thus, it is assumed that the variation of ozone trend of Asian region affecting the ozone trend in Jeju, where domestic ozone photochemical reaction is less active than urban area. It is thought that the photochemical reaction plays the role of increasing of ozone concentrations in the urban area, even though the LRT affected on the increase of ozone concentrations in non-urban area.

• 한국해양공학회지
• /
• 제24권4호
• /
• pp.32-37
• /
• 2010

This study presents the attenuation characteristics of the first guided longitudinal wave mode propagating in water-filled, buried steel pipes in order to investigate the effects of soil saturation and compaction on the attenuation patterns. For numerical calculation of attenuation, 10 different combinations of S-wave velocity, P-wave velocity, and soil densities were considered. From the attenuation dispersion curves, which were obtained using Disperse software, we determined that the attenuation decreases as saturation increases, whereas it increases as compaction increases. Over the frequency range from 0.2 to 0.4 MHz, the first longitudinal wave mode has attenuations that are relatively lower than for other ranges, is faster than the first flexural wave mode, and is sensitive to defects aligned in the axial direction. Hence, the first longitudinal wave mode over the mentioned frequency range would be the proper choice for long-range buried pipelines that transport water.

• 한국해양생명과학회지
• /
• 제2권2호
• /
• pp.39-48
• /
• 2017

생존율은 염분과 관계없이 8℃, 10℃일 때는 98.7~100%였으나, 4℃일 때는 생존율이 25~55%로 나타났다. 혈림프액 내 SOD와 glutathione 농도와 같은 스트레스 지표는 모든 염분구에서 4℃, 6℃일 때 높게 나타났다. THC, hemocyte population, apoptotic cell및 necrotic cell의 비율은 염분 별로는 26 psu구에서 가장 높게 나타났고, 4~6℃일 때 다른 실험구에 비해 유의하게 높았다. 이러한 결과들은 26 psu의 염분과 6℃ 이하의 수온에서는 참전복의 스트레스 반응이 증가하였으나, 30, 34 psu의 염분과 8, 10℃의 수온에서는 대조구와 차이가 없어, 참전복의 수송을 위한 적정 수온 및 염분 조건은 8~10℃, 30~34 psu인 것으로 나타난다.

• Environmental Analysis Health and Toxicology
• /
• 제21권3호
• /
• pp.255-266
• /
• 2006

Soil organic matter (OM) is well documented for its capacity to retain persistent organic pollutants (POPs) and thus is important in dictating the environmental partitioning of POPs between media such as air, water, and soil. Black carbon (BC) is a small component of OM and exhibitt a 10$\sim$100 times greater sorption capacity of POPs than humified OM. Furthermore, due to the inherent long environmental life time of BC, a result of its resistance to physical and biological degradation, POPs can continue to accumulate in BC over a long period of time. The unique properties of BC have been of particular interest over the last 30 years and have resulted in broad research being conducted into its effects of POP cycling in atmospheric, oceanographic and soil matrices. The results of such studies have proved valuable In providing new research initiatives into the role of BC in the cycling of hydrophobic organic compounds (HOCs) as well as giving further insight into the long range atmospheric transport (LRAT) potential and subsequent risk assessment criteria for persistent organic pollutants (POPs). In this report, we introduce a novel study examining the relationships between BC and OM with respect to their POP sorption capacity and discuss the role of BC in influencing the environmental regulation of organic pollutants.

• 한국환경과학회지
• /
• 제26권2호
• /
• pp.183-200
• /
• 2017

The classification of airflow patterns during high ozone ($O_3$) and $PM_{10}$ episodes on Jeju Island in recent years (2009-2015), as well as their correlation with meteorological conditions according to classified airflow patterns were investigated in this study. The airflow patterns for $O_3$ and $PM_{10}$ were classified into four types (Types A-D) and three types (Types E-G), respectively, using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and synoptic weather charts. Type A was the most dominant airflow pattern for $O_3$ episodes, being characterized by the transport of airflows from urban and industrial areas in China with the highest frequency (about 69%, with a mean of 67 ppb). With regard to the $PM_{10}$ episodes, Type E was the most dominant airflow pattern, and was mostly associated with long distance transport from Asian dust source regions along northwesterly winds, having the highest frequency (about 92%, with a mean of $136{\mu}g/m^3$). The variations in the concentration of $O_3$ and $PM_{10}$ during the study period were clarified in correlation with two pollutant and meteorological variables; for example, the high (low) $O_3$ and $PM_{10}$ concentrations with high (low) air temperature and/or wind speed and vice versa for precipitation. The contribution of long-range transport to the observed $PM_{10}$ levels in urban sites for different airflow patterns (Types E-F), if estimated in comparison to the data from the Gosan background site, was found to account for approximately 87-93% (on average) of its input. The overall results of the present study suggest that the variations in $O_3$ and $PM_{10}$ concentrations on Jeju Island are mainly influenced by the transport effect, as well as the contribution of local emissions.

• 한국대기환경학회지
• /
• 제32권4호
• /
• pp.360-371
• /
• 2016

The goal of this research is to examine the recent decade-long (2000~2014) trends of national background concentrations over China, Japan, and Korea. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, which is three-party collaboration project among three countries, we investigated the long-term trends of national background $PM_{10}$ concentrations in three countries over the recent 15 years, including the 2008 Beijing Olympic Game period. In accordance with the agreement among three countries, a total of 8 national background sites: three national background monitoring sites in China (2 sites in Dalian, and 1 in Xiamen), three sites in Korea (Ganghwa, Gosan, and Taean), and two sites in Japan (Oki and Rishiri), were chosen for the trend analysis. The results showed that Chinese background concentration recorded the highest level overall. However, the rapid declining recent trends of annual median ($50^{th}$-percentile) values were surprisingly detected since 2006 or 2007 in every site in China, with the most rapidly decreasing rate (- $18.6{\pm}10.3%$/year) over 2006~2007, and the second most rapidly decreasing rate (- $18.0{\pm}1.5%$/year) over 2007~2008. Based on the previous statistical literature, we concluded that this declining trends were due to the emission reduction of $PM_{10}$ concentrations in China for 2008 Beijing Olympic Game. In Korea, Ganghwa was also showing the decreasing trends over the recent years since 2006, which is also well accorded with the decreasing period of Chinese background concentrations. Taean also implied some impact of Beijing Olympic Game, showing small but detectable decreasing trends, while Gosan showed the increasing tendencies probably due to the near-urban influences. However, since 2012, most sites in both China and Korea showed strong increasing trends, undoubtedly implying the increasement of both emission in China and its long-range transport process toward Korea. Two sites in Japan, Oki and Rishiri recorded the lowest level of $PM_{10}$ level during whole period with the smallest deviations of measurements. Other discussions including the decade-long trends of $5^{th}$, $10^{th}$, $25^{th}$, $50^{th}$, $75^{th}$, $90^{th}$, $95^{th}$-percentiles of $PM_{10}$ background concentrations in three countries were also comparatively addressed here.

• 한국대기환경학회지
• /
• 제33권3호
• /
• pp.217-232
• /
• 2017

An Eulerian-Lagrangian hybrid modeling system to analyze physical and chemical processes during the transport of air parcels was developed. The Backward-tracking Model Analyzer (BMA) was designed to take advantages of both Eulerian and Lagrangian modeling approaches. Simulated trajectories from the National Oceanic and Atmospheric Administration HYSPLIT model were combined with the US Environmental Protection Agency Community Multi-scale Air Quality (CMAQ)-simulated concentrations and additional diagnostic analyses. In this study, we first introduced a generalized methodology to seamlessly match polylines (HYSPLIT) and threedimensional polygons (CMAQ), which enables mass-conservative analyses of physio-chemical processes of transporting air parcels. Two applications of the BMA were conducted: (1) a long-range transport case of pollutant plume across the Yellow Sea using CMAQ Integrated Process Rate analyses, and (2) a domestic circulation of pollutants within (and near) the South Korea based on the sulfate tracking analyzer. The first episode demonstrated a secondary formation of nitrate and ammonium during the transport over the Yellow Sea while sulfate is mostly transported after being formed over the China, and the second episode demonstrated a dominant impact of boundary condition with active sulfate formation from gas-phase oxidation near the Seoul Metropolitan Area.

• 생명과학회지
• /
• 제21권8호
• /
• pp.1076-1082
• /
• 2011

미세소관(microtubule) 위를 이동하는 키네신은 분비소포를 이동시키는 운동단백질이다. KIF5s (KIF5A, KIF5B and KIF5C)는 세포막으로 싸인 각종 세포 내 소기관과 결합하여 미세소관을 따라 목적지까지 이동시킨다는 결과는 알려져 있지만, 어떻게 상대의 cargo를 인식하는지는 밝혀지지 않았다. 본 연구는 KIF5B의 결합 단백질을 동정하기 위하여 효모 two-hybrid system을 사용하여 KIF5B와 특이적으로 결합하는 Myo9b을 확인하였다. Myo9b는 액틴위를 이동하는 운동단백질로 다른 KIF5s들과도 결합함을 효모 two-hybrid assay로 확인하였다. 또한 Myo9s의 GTPase 활성화 단백질(GAP) 영역은 KIF5B와 결합하는데 필수영역임을 확인하였고, 이러한 단백질간의 결합은 Glutathione S-transferase (GST) pull-down assay를 통하여서도 확인하였다. 생쥐의 뇌 파쇄액에 KIF5B들의 항체로 면역침강을 행하여 Myo9s 단백질을 확인한 결과, KIF5s는 Myo9s 단백질과 특이적으로 함께 침강하였다. 이러한 결과들은 kinesin-I는 액틴 결합 운동단백질과 직접 결합함을 보여준다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제1권1호
• /
• pp.19-33
• /
• 1997

The high oxidants, which occur the daily maximum concentrations in the afternoon, are transported into the other region via long range transport mechanisms or trapped within the shallow mixing boundary layer and then removed physically (deposition, transport by mountain wind, etc.) and chemically (reaction with local sources). Therefore, modeling formation of photochemical oxidants requires a complex description of both chemical and meteorological processes. In this study, as a part of air quality studies, we reviewed various aspects of photochemical modeling on the basis of currently available literature. The result of the review shows that the model is based on a set of coupled continuity equations describing advection, diffusion, transport, deposition, chemistry, emission. Also photochemical oxidant models require a large amount of input data concerned with all aspects of the ozone life cycle. First, emission inventories of hydrocarbon and nitrogen oxides, with appropriate spatial and temporal resolution. Second, chemical and photochemical data allowing the quantitative description of the formation of ozone and other photochemically-generated secondary pollutants. Third, dry deposition mechanisms particularly for ozone, PAN and hydrogen peroxide to account for their removal by absorption on the ground, crops, natural vegetation, man-made and water surfaces. Finally, meteorological data describing the transport of primary pollutants away from their sources and of secondary pollutants towards the sensitive receptors where environmental damage may occur. In order to improve our present study, shortcomings and limitation of existing models are pointed out and verification process through observation is emphasized.

• Journal of the korean society of oceanography
• /
• 제32권4호
• /
• pp.181-190
• /
• 1997

A large subtidal sand ridge (Jungang Satoe) in Asan Bay, on the west coast of Korea, was studied in order to understand the morphology and sediment transport trend in a macrotidal setting, by means of analyzing sediment samples, current data, side-scan sonographs and seismic profiles. The ridge is about 15 km long and 2-5 km wide, with a relief of about 15 m. It is elongated in the flow direction of flood (SE) and ebb (NW) tidal currents, but asymmetrical in cross section. The western and southwestern side of the ridge is characterized by relatively gentle slopes averaging 0.4$^{\circ}$, whereas on the northeastern side, relatively steep slopes were mapped with 1.6$^{\circ}$ slope angles. Tidal currents associated with the ridge are very strong; maximum surface velo-cities range from neap values of 50 cm/s to spring values of 130 cm/s. The shear velocities during flood and ebb are strong enough to erode and transport sands on the ridge. Sand waves and megaripples (dunes) are the most common bedforms produced by the tidal currents, which show regional differences in shape and size on the ridge. The distribution pattern of these bedforms in-dicates that the flood tidal currents are dominant on the offshore (northwest) side of the ridge, whereas the onsho.e (southeast) side of the ridge is ebb-dominated. The sand transport path as inferred from bedform orientations is directed toward the ridge crest on the flanks, whereas on the crest, it is near-longitudinal to the ridge axis. The convergent, upslope movement of sands on the ridge flanks appears to be important in sand ridge building and maintenance. A significant ridge migration toward the northeast can be suspected on the basis of the ridge morphology, which may cause offshore hazards for navigation.