• Journal of Astronomy and Space Sciences
• /
• v.32 no.2
• /
• pp.121-125
• /
• 2015

At the suggestion of the NASA Meteoroid Environment Office (NASA/MEO), which promotes lunar impact monitoring worldwide during NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission period (launched Sept. 2013), we set up a video observation system for lunar impact flashes using a 16-inch educational telescope at Chungnam National University. From Oct. 2013 through Apr. 2014, we recorded 80 hours of video observation of the unilluminated part of the crescent moon in the evening hours. We found a plausible candidate impact flash on Feb. 3, 2014 at selenographic longitude $2.1^{\circ}$ and latitude $25.4^{\circ}$. The flash lasted for 0.2 s and the light curve was asymmetric with a slow decrease after a peak brightness of $8.7{\pm}0.3mag$. Based on a star-like distribution of pixel brightness and asymmetric light curve, we conclude that the observed flash was due to a meteoroid impact on the lunar surface. Since unequivocal detection of an impact flash requires simultaneous observation from at least two sites, we strongly recommend that other institutes and universities in Korea set up similar inexpensive monitoring systems involving educational or amateur telescopes, and that they collaborate in the near future.

• Journal of Environmental Science International
• /
• v.22 no.6
• /
• pp.651-666
• /
• 2013

This study introduces a novel approach to the differentiation of two phenomena, Asian Dust and haze, which are extremely difficult to distinguish based solely on comparisons of PM10 concentration, through use of the Optical Particle Counter (OPC), which simultaneously generates PM10, PM2.5 and PM1.0 concentration. In the case of Asian Dust, PM10 concentration rose to the exclusion of PM2.5 and PM1.0 concentration. The relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration were below 40%, which is consistent with the conclusion that Asian Dust, as a prime example of the coarse-particle phenomenon, only impacts PM10 concentration, not PM2.5 and PM1.0 concentration. In contrast, PM10, PM2.5 and PM1.0 concentration simultaneously increased with haze. The relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration were generally above 70%. In this case, PM1.0 concentration varies because a haze event consists of secondary aerosol in the fine-mode, and the relative ratios of PM10 and PM2.5 concentration remain intact as these values already subsume PM1.0 concentration. The sequential shift of the peaks in PM10, PM2.5 and PM1.0 concentrations also serve to individually track the transport of coarse-mode versus fine-mode aerosols. The distinction in the relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration in an Asian Dust versus a haze event, when collected on a national or global scale using OPC monitoring networks, provides realistic information on outbreaks and transport of Asian Dust and haze.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.2
• /
• pp.113.1-113.1
• /
• 2014

We propose a three-year Key Science Program (KSP) consisting of VLBI monitoring observations and single dish (SD) rapid response observations (RRO). The VLBI monitoring observations are comprised of ten 24-hr observations per year (every month) of about 30 gamma-ray brigt active galactic nuclei (AGNs) with Korea VLBI Network (KVN) at 22, 43, 86, and 129 GHz. The SD RROs may consist of twelve 7-hr observations per source (every week for 3 months after triggering) of gamma-ray flaring sources with two KVN SD telescopes at 22, 43, and 86 GHz in dual polarization. We expect one or two sources per year for the SD RROs. Gamma-ray flares of AGNs are known to be occured in innermost regions of relativistic jets which radiate in whole ranges of electromagnetic spectra due to synchrotron radiation, syschrotron self absorption, inverse-compton scttering, doppler boosting etc. Possible explanations of the gamma-ray flares in AGNs are a) shocks-in-jets propagating within jet flow and b) bending of the whole jets. For both cases, we should expect changes in polarization, luminosity, particle distribution, and structures of jets at mas-scale. The multifrequency simultaneous VLBI/SD observations with KVN are the best tool for detecting such changes correlated with gamma-ray flares. This KSP proposal aims to answer the fundamental questions about the basic nature of the flares of AGNs.

• Toxicological Research
• /
• v.18 no.2
• /
• pp.205-213
• /
• 2002

This study was undertaken to develop a subacute murine model for predicting occurrence of systemic anaphylaxis and to evaluate efficacy of various immunological parameters as the monitoring indices for the occurrence of anaphyalxis. The murine anaphyalxis model was developed through intraperitoneally sensitizing 100 $\mu\textrm{g}$ ovalbumin (OVA) in the presence of 1 mg alum and 300 ng cholera toxin twice a week interval followed by challenging 500 $\mu\textrm{g}$. OVA intravenously. Typical anaphylaxis symptoms were demonstrated at the both BALB/c mice, a strain prone to type-2 response, and C57BL/6 mice. a strain prone to type-1 response. Level of plasma histamine was approximately 50-fold or 30-fold higher in the mice sensitized with OVA than the mice sensitized with alum plus cholera toxin or the saline-treated mice after OVA challenge, respectively. Sensitization and challenge with OVA significantly enhanced plasma leukotriene $B_4$ level but not IgE levels in comparison with the control mice, which indicated the role of leukotriene $B_4$ for progression of anaphyalxis. Furthermore, among mice suffered from anaphylaxis, levels of OVA-specific IgGl were significantly higher in the BALB/c mice than in the C57BL/6 mice, which implied the genetic susceptibility for the induction of systemic anaphylaxis. Conclusively, simultaneous evaluation of histamine, leukotriene $B_4$, and allergen-specific IgG isotype may serve as more efficient monitoring tool for vaccine-related anaphyalxis.

• Journal of Korea Port Economic Association
• /
• v.30 no.3
• /
• pp.15-37
• /
• 2014

Sustainability is a broad concept involving economic, social and environmental issues in operational and managerial processes. To assist ports to implant sustainability practices into their operations, this paper conceptualizes the structure of sustainability practice in port operations, based on interviews undertaken at Busan port in early 2013. Results revealed that, as a strategic practice to improve their internal business processes, sustainability practices necessitate the simultaneous pursuit of container traffic growth, low environmental impacts and corporate responsible image making, operational efficiency, efficiency of the use of the port area and sustainable growth. Through thematic analysis, the relevant practices were clustered into four sub-dimensions incorporating environmental technologies, continual monitoring and upgrading, internal process improvement, and cooperation and communication. Further, reporting the relevant issues such as barriers and challenges in carrying out sustainability practices, the findings provide useful insights for strategic agenda to assist ports to incorporate sustainability practices in their operations.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.60-60
• /
• 2017

It is important to measure the gas exchange activity of the crops in canopy scale to understand the process of biomass production and yield formation. Thermal imaging of the canopy surface temperature is a powerful tool to detect the gas exchange activity of the crop canopy. The simultaneous measurement of the canopy temperature and the meteorological data enables us to calculate the canopy diffusive conductance ($g_c$) based on the heat flux model (Monteith et al. 1973, Horie et al. 2006). It is, however, difficult to realize the long-term and continuous monitoring of $g_c$ due to the occurrence of the calculation error caused by the fluctuation of the environmental condition. This is partly because the model assumption is too simple to describe the meteorological and aerodynamic conditions of the crop canopy in the field condition. Here we report the novel method of the direct measurement of the aerodynamic resistance ($r_a$) of the crop canopy, which enables us the stable and continuous measurement of the gas exchange capacity of the crop plants. The modified heat balance model shows the improved performance to quantify $g_c$ under the fluctuating meteorological condition in the field. The relationship between $g_c$ and biomass production of rice and soybean varieties is also discussed in the presentation.

• Journal of The Korean Astronomical Society
• /
• v.48 no.5
• /
• pp.237-255
• /
• 2015

The Interferometric Monitoring of Gamma–ray Bright Active galactic nuclei (iMOGABA) program provides not only simultaneous multifrequency observations of bright gamma–ray detected active galactic nuclei (AGN), but also covers the highest Very Large Baseline Interferometry (VLBI) frequencies ever being systematically monitored, up to 129 GHz. However, observation and imaging of weak sources at the highest observed frequencies is very challenging. In the second paper in this series, we evaluate the viability of the frequency phase transfer technique to iMOGABA in order to obtain larger coherence time at the higher frequencies of this program (86 and 129 GHz) and image additional sources that were not detected using standard techniques. We find that this method is applicable to the iMOGABA program even under non–optimal weather conditions.

• Journal of Korean Society for Geospatial Information Science
• /
• v.4 no.2 s.8
• /
• pp.23-33
• /
• 1996

The conventional monitoring of water quality constrained by time and equipment produce neither complete nor synoptic geographic coverage of pollutant distribution, transport, and water quality. To circumvent these limitations in temporal and spatial measurements, the use of remote sensing is increasingly being involved in the lacustrine environmental research. Consequently, satellite remote sensing, with its synoptic coverage, is used to obtain the eutrophication-related water quality parameters in Daecheong reservoir in this study. The approach involved acquisition of water quality samples from boats of 15 sites on 20 June 1995 and 30 sites on 18 March 1996, simultaneous with Landsat-5 satellite overpass. Regression models have been developed between the water quality parameters and Landsat Thematic Mapper(TM) digital data. The best regression model was determined based on the correlation coefficient which was higher than 0.6. As a result, satellite remote sensing can provide meaningful information on water quality parameters. The regression models developed in this study show good relationship for transparency, turbidity, SS, and chlorophyll, but not for TN and TP because their spectral characteristics are not well defined.

• Analytical Science and Technology
• /
• v.13 no.5
• /
• pp.592-600
• /
• 2000

The concentration of free fatty acids and fatty acid composition as well as cholesterol supersaturation in bile may be an important factor in the gallstone formation. Therefore, we simultaneously determinded 23 fatty acids in bile by selected ion monitoring (SIM) method of gas chromatography-mass spectrometry (GC-MS). Biliary fatty acids were extracted by aminopropyl column and the extracts with (phospholipid fraction) or without (free fatty acid fraction) alkaline hydrolysis of phospholipid were derivatized with MSTFA/TMCS (N-methyl-N-trimethylsilyl-trifluoroacetamide/trimethylsilylchloride) mixture in order to be detected on the GC-MS. The recovery range of this method was 61.1-99.0% and the RSD value of within-a-day and day-to-day test were 3.1-25.6% and 3.8-27.0%, respectively. Using this method, biliary profile was investigated in the bile of normal controls and patients with gallstones. The amounts and their distribution of free and phospholipid fatty acids showed different pattern between normal subjects and patients.

• Analytical Science and Technology
• /
• v.12 no.4
• /
• pp.265-272
• /
• 1999

A simultaneous profile analysis of 19 environmental estrogens, which act like estrogen and may effect the endocrine system by binding to hormone receptors or influencing cell signaling pathways, was attempted. The present method was based on the selected ion monitoring (SIM) mode of gas chromatography/mass spectrometry (GC/MS). It involves solid-liquid extraction, enzyme hydrolysis, liquid-liquid extraction and quantitative conversion into trimethylsilyl (TMS)-ether derivatives. Analytical recovery range was 47.6 ~ 99.5% and the RSD values of within-a-day and day-to-day test were 0.66 ~ 9.33%, 1.66 ~ 16.14%, respectively. The Korean reference values for the evaluation of environmental estrogen effects were established by this method.