• Journal of Korean Society of Disaster and Security
• /
• v.13 no.4
• /
• pp.93-104
• /
• 2020

Climate change has emerged as a social issue, and efforts have been made to overcome it in various ways. However, climate change due to global warming is likely to accelerate further than we expected, and the associated damage is also likely to increase. This tendency is expected to continue in the future, leading to difficulties for the existing water resource management system based on historical data. The precipitation in 2020 caused property damage and loss of life due to the extreme rainfall exceeding the design rainfall with the very unusual prolonged rainy days. With this 2020 flood, we should no longer be passive in managing flood risk due to uncertainties in climate change.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.8
• /
• pp.4059-4062
• /
• 2016

Frequencies of polymorphisms of genes BRCA1 and ТР53 in breast cancer (BC) patients with a BC family history and radiation history were assessed and compared in the Semey region of Kazakhstan. The study included 60 women directly irradiated by the activities of the Semipalatinsk test site with a calculated effective equivalent dose of 500 mSv and their first generation descendants (group BC+Her+Exp); 65 women with family BC and absence of radiological history - the effective equivalent dose due to anthropogenic sources not exceeding 50 mSv (group BC+Her-Exp). The comparison group consisted of 65 women patients with breast cancer without family and radiological history (BC-Her-Exp). The control group comprised 60 women without breast cancer and without family and radiological history (nonBC). We carried out the genotyping of the polymorphisms c.2311T>C, c.4308T>C and 5382insC of the BRCA1 gene and rs1042522 of the ТР53 gene. The frequency of the polymorphism c.2311T>C was significantly higher in patients of the group BC+Her+Exp than in healthy women, and of the polymorphism 5382insC in BC+Her+Exp compared to all other groups. The frequency of the rs1042522 polymorphism of ТР53 was significantly higher in all groups of patients with breast cancer compared with the control group. Differences between groups of women with breast cancer were significant only in BC+Her+Exp vs. BC+Her-Exp. Combinations of polymorphisms of the genes BRCA1 and TP53 predominated in women with a family and radiological history.

• Journal of Oriental Neuropsychiatry
• /
• v.9 no.2
• /
• pp.37-44
• /
• 1998

Purpose: This study was conducted to find out the effects od Sahyangsohapwon on learning and memory of rats.Method: In the experiment, rats were divided two groups. One was control group which was adminstered Sahyangsohapwon and the other was sample group administered placebo. Numbers of each group were 13 rats. 8-arm radial maze task was used in it, and working memory test and retention(reference memory) test were done.Before the beginning of the test, the rats were deprived of water for 24hrs.In the frist test, each of eight arm was baited with water and a rat was permitted to remain on the maze until all eight arms were entered. A working memory error was defined as revisit of any previously entered arm. When a rat made an error not exceeding one time in consecutive 3 days-performance, it was regarded as learning criteria and the test was ended. The reference memory was evaluated with total days which it took rats to pass the learning crtirtia.The second test was performed after 24 hours when the first test was over. When a rat entered 4 arms, the entrance of arm was cut off during 30 seconds.Here the number if errors which was produced during a rat find remaining 4 tracks was regarded as the index of memory.This experiment compared the number of error at the control group with that of the sample group.Result: 1. In the first test, it was shown that the sample group took 7.69${\pm}$1.11 days and the control group 9.31${\pm}$1.97 days to pass the learning criteria.There was statistically significant reference mernory development at the sample group.2. In the second test, the frequency of errors made by the two groups were 0.92${\pm}$1.32 times for the control group and 1.23${\pm}$1.59 times for the Sahyangsohapwon group. There was no difference between the groups in frequency of errors.Conclusion: It is suggested that Sahyangsohapwon has effects on the improvement of learning and memory.

• Journal of the Korean association of regional geographers
• /
• v.20 no.4
• /
• pp.393-408
• /
• 2014

In this study, the spatio-temporal characteristics of summer extreme precipitation events in the Republic of Korea are examined based on the daily precipitation data observed at approximately 360 sites of both Automatic Weather Station (AWS) and Automated Synoptic Observation System (ASOS) networks by the Korea Meteorological Administration for the recent decade(2002~2011). During the summer Changma period(late June~mid July), both the frequency of extreme precipitation events exceeding 80mm of daily precipitation and their decadal maximum values are greatest at most of weather stations. In contrast, during the Changma pause period (late July~early August), these patterns are observed only in the northern regions of Geyeonggi province and western Kangwon province as such patterns are detected around Mt. Sobaek and Mt. Halla as well as in the southern regions of Geyeonggi province and western Kangwon province during the late Changma period (mid August~early September) due to north-south oscillation of the Changma front. Investigation of their regional patterns confirms that not only migration of the Changma front but also topological components in response to the advection of moistures such as elevation and aspect of major mountain ridges are detrimental to spatio-temporal patterns of extreme precipitation events. These results indicate that each local administration needs differentiated strategies to mitigate the potential damages by extreme precipitation events due to the spatiotemporal heterogeneity of their frequency and intensity during each Changma period.

• Journal of the Korean Geotechnical Society
• /
• v.32 no.8
• /
• pp.5-14
• /
• 2016

The leakage of water under sewer pipelines is one of main sources of sinkholes in urban areas. We performed laboratory model tests to investigate the presence of cavities using impact-echo method, which is a nondestructive test method. To simulate a concrete sewer pipe, a thin concrete plate was built and placed over container filled with sand. The cavity was modeled as an extruded polystyrene foam box. Two sets of tests were performed, one over sand and the other on cavity. A new impact device was developed to apply a consistent high frequency impact load on the concrete plate, thereby increasing the reliability of the test procedure. The frequency and transient characteristics of the measured reflected waveforms were analyzed via fast Fourier transform and short time Fourier spectrum. It was shown that the shapes of Fourier spectra are very similar to one another, and therefore cannot be used to predict the presence of cavity. A new index, termed resonance duration, is defined to record the time of vibration exceeding a prescribed intensity. The results showed that the resonance duration is a more effective parameter for predicting the presence of a cavity. A value of the resonance period was proposed to estimate the presence of cavity. Further studies using various soil types and field tests are warranted to validate the proposed approach.

• Research in Community and Public Health Nursing
• /
• v.33 no.1
• /
• pp.13-31
• /
• 2022

Purpose: This study conducted a job analysis of visiting nurses in the process of change. Methods: Participants were the visiting nurses working for the Seoul Metropolitan city. On the basis of the Public Health Intervention Wheel model, two times of the focus group interview (FGI) with seven visiting nurses and one time of the Developing a Curriculum (DACUM) with 34 visiting nurses were performed. A questionnaire survey of 380 visiting nurses was conducted to examine the frequency, importance and difficulty levels of the tasks created by using the FGI and DACUM. Results: Visiting nurses' job was derived as the theme of present versus transitional roles. The present role was categorized as 'providing individual- and group-focused services' and 'conducting organization management', while the transitional role was categorized as 'providing district-focused services' and 'responding to new health issues'. The job generated 13 duties, 28 tasks, and 73task elements. The tasks showed the levels of frequency (3.65 scores), importance (4.27 scores), and difficulty (3.81 scores). All the tasks were determined as important, exceeding the average 4.00 scores. The group- and district-focused services of the tasks were recognized as more difficult but less frequent tasks. Conclusion: The visiting nurses exert both present and transitional roles. The transitional roles identified in the present study should be recognized as an extended role of visiting nurses in accordance with the current changing healthcare needs in South Korea. Finally, the educational curriculum for visiting nurses that reflects the transitional roles from the present study is needed.

• Applied Chemistry for Engineering
• /
• v.17 no.6
• /
• pp.644-647
• /
• 2006

The indium zinc oxide (IZO) thin films were deposited using a radio frequency reactive magnetron sputtering method. Among the various processing variables, $O_{2}$ concentration and annealing temperature after deposition were selected and the optical, electrical, and structural properties of IZO thin films were investigated. As the $O_{2}$ concentration increased, the deposition rate of IZO thin films decreased, the resistivity increased and the transmittance slightly increased. According to atomic force microscopy analysis, the IZO films deposited at pure Ar showed rough surface and those deposited with $O_{2}$ addition exhibited relatively smooth surface. The IZO thin films deposited at pure Ar were annealed at 250, 350, and $450^{\circ}C$, respectively. The IZO thin film deposited at pure Ar showed the lowest transmittance and resistivity and resistivity greatly increased at the annealing temperature exceeding $250^{\circ}C$. The higher annealing temperature IZO films were annealed at, the smoother surface the films showed. The x-ray diffraction revealed that IZO films annealed at higher temperature had better crystalline structures.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.1-2
• /
• 2011

Hybrid rockets have lately attracted attention as a strong candidate of small, low cost, safe and reliable launch vehicles. A significant topic is that the first commercially sponsored space ship, SpaceShipOne vehicle chose a hybrid rocket. The main factors for the choice were safety of operation, system cost, quick turnaround, and thrust termination. In Japan, five universities including Hokkaido University and three private companies organized "Hybrid Rocket Research Group" from 1998 to 2002. Their main purpose was to downsize the cost and scale of rocket experiments. In 2002, UNISEC (University Space Engineering Consortium) and HASTIC (Hokkaido Aerospace Science and Technology Incubation Center) took over the educational and R&D rocket activities respectively and the research group dissolved. In 2008, JAXA/ISAS and eleven universities formed "Hybrid Rocket Research Working Group" as a subcommittee of the Steering Committee for Space Engineering in ISAS. Their goal is to demonstrate technical feasibility of lowcost and high frequency launches of nano/micro satellites into sun-synchronous orbits. Hybrid rockets use a combination of solid and liquid propellants. Usually the fuel is in a solid phase. A serious problem of hybrid rockets is the low regression rate of the solid fuel. In single port hybrids the low regression rate below 1 mm/s causes large L/D exceeding a hundred and small fuel loading ratio falling below 0.3. Multi-port hybrids are a typical solution to solve this problem. However, this solution is not the mainstream in Japan. Another approach is to use high regression rate fuels. For example, a fuel regression rate of 4 mm/s decreases L/D to around 10 and increases the loading ratio to around 0.75. Liquefying fuels such as paraffins are strong candidates for high regression fuels and subject of active research in Japan too. Nakagawa et al. in Tokai University employed EVA (Ethylene Vinyl Acetate) to modify viscosity of paraffin based fuels and investigated the effect of viscosity on regression rates. Wada et al. in Akita University employed LTP (Low melting ThermoPlastic) as another candidate of liquefying fuels and demonstrated high regression rates comparable to paraffin fuels. Hori et al. in JAXA/ISAS employed glycidylazide-poly(ethylene glycol) (GAP-PEG) copolymers as high regression rate fuels and modified the combustion characteristics by changing the PEG mixing ratio. Regression rate improvement by changing internal ballistics is another stream of research. The author proposed a new fuel configuration named "CAMUI" in 1998. CAMUI comes from an abbreviation of "cascaded multistage impinging-jet" meaning the distinctive flow field. A CAMUI type fuel grain consists of several cylindrical fuel blocks with two ports in axial direction. The port alignment shifts 90 degrees with each other to make jets out of ports impinge on the upstream end face of the downstream fuel block, resulting in intense heat transfer to the fuel. Yuasa et al. in Tokyo Metropolitan University employed swirling injection method and improved regression rates more than three times higher. However, regression rate distribution along the axis is not uniform due to the decay of the swirl strength. Aso et al. in Kyushu University employed multi-swirl injection to solve this problem. Combinations of swirling injection and paraffin based fuel have been tried and some results show very high regression rates exceeding ten times of conventional one. High fuel regression rates by new fuel, new internal ballistics, or combination of them require faster fuel-oxidizer mixing to maintain combustion efficiency. Nakagawa et al. succeeded to improve combustion efficiency of a paraffin-based fuel from 77% to 96% by a baffle plate. Another effective approach some researchers are trying is to use an aft-chamber to increase residence time. Better understanding of the new flow fields is necessary to reveal basic mechanisms of regression enhancement. Yuasa et al. visualized the combustion field in a swirling injection type motor. Nakagawa et al. observed boundary layer combustion of wax-based fuels. To understand detailed flow structures in swirling flow type hybrids, Sawada et al. (Tohoku Univ.), Teramoto et al. (Univ. of Tokyo), Shimada et al. (ISAS), and Tsuboi et al. (Kyushu Inst. Tech.) are trying to simulate the flow field numerically. Main challenges are turbulent reaction, stiffness due to low Mach number flow, fuel regression model, and other non-steady phenomena. Oshima et al. in Hokkaido University simulated CAMUI type flow fields and discussed correspondence relation between regression distribution of a burning surface and the vortex structure over the surface.

• The Korean Journal of Pesticide Science
• /
• v.15 no.2
• /
• pp.114-124
• /
• 2011

The characteristics of pesticide residues by multiresidue analysis method using GC, HPLC and GC-MSD were examined for 18,069 numbers of 91 kinds of vegetables in Seoul from 2007 to 2009. Detection rates of pesticide residues were 11.2% in 2007, 8.5% in 2008 and 12.0% in 2009, respectively, and the excess rates of Maximum Residue Limits (MRLs) showed a declining tendency as 4.6% in 2007, 2.8% in 2008 and 2.1% in 2009, respectively. The pesticides exceeding MRLs were 43 ingredients in 2007, 30 ingredients in 2008 and 36 ingredients in 2009, respectively. The frequencies of pesticides exceeding MRLs were 71 of azoxystrobin in 2007, 29 of procymidone in 2008, 24 of endosulfan in 2009, respectively. The excess rate of mustard green for MRLs in comparison with sample numbers was the highest among vegetables analyzed more than 10 cases each year. As a result of comparing annually pesticide residues about pesticide ingredients showed high frequency rates for pesticide detection, there was a statistical significance for the detection quantities of diazinon, endosulfan, paclobutrazol and procymidone.

• Journal of Environmental Health Sciences
• /
• v.50 no.3
• /
• pp.181-190
• /
• 2024

Background: Air pollutants have been reported to have harmful effects on human health. Busan is a vulnerable area in terms of air quality due to the installation of various industrial complexes, particularly the port industry. However there is limited research data on the ambient air quality of residential areas near ports and industrial complexes. Objectives: This study aimed to determine the quarterly levels of air pollutants near industrial complexes and ports and to identify trends and characteristics of air pollutant exceedances. Methods: Air measurements were conducted quarterly. The measured air pollutants included O₃, SO₂, CO, NO₂, PM₁₀, and PM_2.5. PM₁₀ and PM_2.5 were measured using BAM-1020 equipment, while O₃, SO₂, CO, and NO₂ were measured using AP-370 Series equipment. The quarterly concentration levels of air pollutants were determined, and the influence of precipitation and commuting hours on fine particulate matter was examined. Analysis of variance (ANOVA) was conducted to determine if there was significance between the concentrations of fine particulate matter during commuting hours and non-commuting hours. Results: The concentrations of air pollutants were generally higher in the first and second quarters. Furthermore, the concentrations of PM₁₀ and PM_2.5 tended to decrease continuously following consecutive rainfall, with concentrations at the end of rainfall periods lower than those observed at the beginning. The frequency of exceeding average concentrations of PM₁₀ and PM_2.5 was higher on weekdays. Moreover, the average concentrations of PM₁₀ and PM_2.5 during weekday commuting hours were higher compared to non-commuting hours. Conclusions: The concentrations of air pollutants in the survey area were found to be higher than the overall average in Busan. Based on this study, continuous air quality monitoring is necessary for residential areas near industrial complexes and ports. For further research, health biomonitoring of residents in these areas should be conducted to assess their exposure levels.