• Economic and Environmental Geology
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• v.28 no.5
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• pp.469-480
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• 1995

Gravity and magnetic surveys were carried out to investigate the three-dimensional configuration and characteristics of the landfills at Nanjido waste disposal site. For terrain correction and three-dimensional density inversion of gravity data an algorithm, which calculates the gravity effect of a three-dimensional body by using the solid angle method, is developed. This algorithm has been proved to give more accurate terrain correction values for the small survey area having varied topography like Nanjido site as compared with widely used methods such as Hammer's method and multiquadric equation method. Density inversion of gravity anomaly data gives very useful information about the lateral and vertical variation of the landfills, which can be used to discriminate the kinds of wastes. The average density of filled materials appears to be $1.7\;g/cm^3$ which is much higher than the value $(0.8\;g/cm^3)$ estimated by Seoul City. The lateral variation of density shows high correlation with the pattern of ongoing depression of the landfills. The northern region of the landfill no. 1, which shows low density and high depression, is closely associated with the industrial waste and sludge filled area. The magnetic anomaly data provide information about relative concentration of magnetic materials, which is also very useful to investigate characteristics of the fills. Several high positive anomaly regions on the reduced-to-pole magnetic anomaly map are appeared to be associated with the industrial waste fills, but certain industrial waste fills show low negative anomalies. This kind of magnetic information can be used in selecting drilling locations over landfills away from buried metal products during the stabilization process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.535-544
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• 1998

Seasonal variation of the crab community in the eelgrass (Zostera marina) bed in Kwangyang Bay was studied based on the monthly collections through a year of 1994. The crab community in the eelgrass bed was composed of 21 species representing 12 families. The community was dominated by Charybdis Japonica, Telmessus acutidens, Hemigrapsus penicillatus, and Pugettia quadridens. Crabs collected in the study area were primarily small-sized species or early juveniles of large crab species. Most individuals had carapace width smaller than 25 mm except C. japonica and T. acutidens which had maximum carapace width over 85 mm. More than 5 species were collected every month except January and February (4 and 3 species, respectively). The peak abundance occurred in August and low abundances in autumn and winter. Species diversity indices showed that more diverse crabs were collected In spring and summer, and lesser ones in autumn and winter. The crabs in the study area can be grouped into three groups on the basis of their occurrence patterns: resident species, seasonal species, and temporary species. More abundant and more diverse crabs were collected during nighttime than daytime.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.257-266
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• 2019

In this study, we selected 6 vegetation sites (reed community) and 6 non-vegetation sites (tidal flat) in the Muan tidal flat of Hampyeong Bay, and observed seasonal changes in carbon dioxide concentration, flux and soil temperature at low tide conditions. The study was conducted to identify the characteristics of seasonal changes in vegetation and non-vegetation areas through the data observed in May 30, August 8, 2012 and January 31, 2013. The average carbon dioxide concentration in the vegetation area was the highest in winter, followed by spring and summer, and the non-vegetation area showed the same concentration change as the vegetation area. The carbon dioxide flux in the vegetation area showed a positive (+) value in both spring and summer, but it was negative (-) in the winter. The average value of carbon dioxide flux was the highest in spring, but it was almost similar to summer, and winter was the lowest negative value. Non-vegetation areas showed positive emission in spring, and negative uptake in summer and winter; mean values were the highest in spring, and the difference between summer and winter was small. In summary of seasonal change characteristics of the research area, the emission of carbon dioxide was dominant in both areas in spring. In summer, carbon dioxide emission was dominant in the vegetation area, and the non-vegetation area was observed to uptake by photosynthesis of phytoplankton, but it was very small. In winter, changes in flux in both areas were very slight.

• Korean Journal of Plant Resources
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• v.14 no.2
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• pp.133-138
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• 2001

This study was conducted to investigate the relationships between yearly variations of elimatic elements and yearly variations of productivity in potato. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components were investigated for 9 years from 1987 to 1995. The meteorological data what gathered at the Goheung Weather Station for the same period of crop growing season were used to find out the relationships between climatic elements and crop productivity. Yearly variation of the daily minimum temperature in March and April were large with coefficients of variation (C.V.) of 126.0%,368.0%, respectively, but the variation of the daily mean and maximum temperature in May and June were relative small. Stem length and number of stem show more C.V. of 9.3% ,14.3%, respectively, but the variation of the yield was relative small with 3.7%. Correlation coefficients between the amount of precipitation in April and yield, yield and daily mean temperature in June were negatively significant at the level of 5, 1%, respectively. Correlation coefficients between the growth habits and yield are positively significant at the level of 5, 1%, respectively. Simple linear regression equations by the least square method are estimated for stem length $(Y_1)$ and the precipitation in April(X) as $Y_1=82.47-0.11{\times}(R_2=0.3959)$, and for yield$(Y_2)$ and the precipitation in April(X) as $Y_2=2003.61-0.94{\times}(R_2=0.5418)$.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.36-41
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• 1999

Although the problems of defects and nonmetallic inclusion in metal fatigue are very complicated it is particularly important to view these problems from the perspective that defects and inclusions are virtually equivalent to small cracks. This concept will help us to understand various fatigue phenomena caused by graphite of Ductile cast iron. Therefore in this study different ferrite-pearlite matrix structure and pheroidal ratio of graphite of 70%, 80% and 90% GCD40 , GCD45-2 series have been carried out rotary bending fatigue test estimated the maxi-mum size of graphite investigated correlation. It was concluded as follows : (1) in ductile cast iron which have various spheroidal ratio of graphite the fatigue limit C series of 90% spheroidal ratio of graphite is the highest. While A series of 70% spheroidal ratio of graphite is the lowest (2) fatigue limit was predicted by vickers hardness(Hv) of matrix {{{{ SQRT {area } }}}} of maximum size graphite inputting Murakami and Endo's formula.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.201-211
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• 2008

This study was performed to find the atmospheric concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) at four different heights (l0, 50, 150 and 1,500 cm) using low volume polyurethane foam (PUF) plug air sampler in semi-rural area. ${\alpha}-/{\beta}-/{\gamma}-HCH$ with low molecular weights and Koa (octanol-air partitioning coefficient) in OCPs were similarly high concentrations at all heights, but the other OCPs (p,p'-DDE, p,p'-DDD, p,p'-DDT, Heptachlor epoxide, ${\gamma}$-CHL, ${\alpha}$-CHL, Trans-nonachlor) with high molecular weights and Koa decreased with increasing heights. However, the concentrations of PCBs increased with increasing height.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.437-444
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• 2015

A high output power voltage controlled oscillator (VCO) in the U-band was implemented using a 65 nm CMOS process. The proposed VCO used a transmission line to increase output voltage swing and overcome the limitations of CMOS technologies. Two varactor banks were used for fine tuning with a 5% frequency tuning range. The proposed VCO showed small variation in output voltage and operated at 51.55-54.18 GHz. The measured phase noises were -51.53 dBc/Hz, -91.84 dBc/Hz, and -101.07 dBc/Hz at offset frequencies of 10 kHz, 1 MHz, and 10 MHz, respectively, with stable output power. The chip area, including the output buffer, is $0.16{\times}0.16mm^2$ and the maximum output power was -0.11 dBm. The power consumption was 33.4 mW with a supply voltage of 1.2-V. The measured $FOM_P$ was -190.8 dBc/Hz.

• International Journal of Human Ecology
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• v.8 no.1
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• pp.19-26
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• 2007

The object of this research was to observe the female college 220 students of aged 19-24 for four years and to examine somatotypes distribution; this research intends to contribute to the fitness of clothes by studying the body distribution that affects the clothing structure. The measurement and wearing experiment for somatotypes are done years annually. The average, standard deviation and coefficient of variation was calculated by the SAS program. The research results are as follows: The three somatotypes of side view silhouette (straight type, bend-forward type, lean-back type) showed fairly even distribution. As a result of dressing experiment with the basic bodice pattern, the most influential factor on its suitability was found to be the neck area, shoulder and ease of bodice respectively. The partial body types to observe were categorized as: shoulder(normal, slope, squared), bust(A cup, B cup, C cup), hips (normal, droop, projecting). As for the result for full body type by BMI, normal type was most dominant, and for the categorization by drop, the type A which is with small breasts and large hips was most prevalent.

• Korean Journal of Hydrosciences
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• v.8
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• pp.85-95
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• 1997

The multiple flow direction algorithm to calculate the spatial variation of the saturation tendency, I. e. topographic index, is integrated into the Geographic Information System, GRASS. A procedure is suggested to consider the effect of a tile system on calculating the topographic index. A small agricultural subwatershed ($3.4\;\textrm{km}^2$) is used for this study. The impact of a tile system on the groundwater table can be effectively considered by the Laplace's equation to the DEM. The analysis shows that a tile system has a high degree of saturation to compared to the case without tile drainage, and the predicted riparian area is well fitted to the actual watershed condition. A procedure is suggested to consider a tile system's effect on calculating the topographic index.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.185-186
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• 2000

For the quantitative investigation of the erosion of MgO layers in real ac-PDP cells, we constructed a microscopic spectrophotometer which is capable of measuring transmission spectra from the area as small as 20 ${\times}$ 20 ${\mu}m^2$. In the test on the sputtered MgO films with a thickness gradient, we were able to probe the thickness variation of 1000 nm over $1000-{\mu}m$ distance. Using this instrument, we were able to determine not only the erosion rate at the particular position of ac-PDP cells but also the relative erosion rate at different positions in a single ac-PDP cell.