• Economic and Environmental Geology
• /
• v.36 no.5
• /
• pp.329-338
• /
• 2003

The purpose of this study is to identify the temporal and spatial variation of stable isotopic compositions of surface waters and shallow ground waters at a local watershed(100$Km^2$) near the Muju area. For oxygen and hydrogen isotope analysis, water samples were collected from 19-22 sites during August, October 2001, through April 2002. Seasonal variation in the isotopic compositions of surface waters was clearly shown. However, the degree of such isotopic variation was highly attenuated in shallow ground waters because of mixing with preexisting ground waters. Isotope values of surface waters and ground waters were very similar in each season, indicating that precipitation/ground water/surface water interactions were very active and continuous in the watershed. Stable isotopic ratios of surface waters in the study area were lighter than those of the downstream reach of Geum River on south, indicating “latitude effect”. Both “altitude effect” and “amount effect” were also shown in the stable isotopic ratios of surface waters in the study area as well as seasonal variation of stable isotopes.

• Journal of Astronomy and Space Sciences
• /
• v.28 no.2
• /
• pp.103-108
• /
• 2011

The latitudinal variation of sunspots appearing during the period from 1874 to 2009 has been studied in terms of centerof-latitude (COL). The butterfly diagram has been used to study the evolution of the magnetic field and the dynamics at the bottom of the solar convection zone. Short-term periodicities have been of particular interest, in that they are somehow related to the structure and dynamics of the solar interior. We thus have focused our investigation on shortterm periodicities. We first calculated COL by averaging the latitude of sunspots with the weight function in area. Then, we analyzed the time series of COL using the wavelet transform technique. We found that a periodicity of ~5 years is the most dominant feature in the time series of COL, with the exception of the ~11 year solar cycle itself. This periodicity can be easily understood by considering small humps between the minima in the area-weighted butterfly diagram. However, we find that periodicities of ~1.3 (0.064), ~1.5 (0.056), or ~1.8 (0.046) years ($\frac{1}{month}$), month ), which have been previously suggested as evidence of links between the changing structure of the sunspot zone and the tachocline rotation rate oscillations, are insignificant and inconsistent. We therefore conclude that the only existing short-term periodicity is of ~5 years, and that periodicities of ~1.3, ~1.5, or ~1.8 years are likely to be artifacts due to random noise of small sunspots.

• Journal of Korea Water Resources Association
• /
• v.36 no.5
• /
• pp.725-740
• /
• 2003

Urbanization concerned with concentration of population, activity and expanding the urban changes a natural environmental, and human activity in urban area causes the appearance of a new hydrologic cycle system. This study is carried out the analysis for the characteristics of runoff variation in urban areas with progress of urbanization. To simulate the mechanics of runoffs on small urban watershed, the ILLUDAS model is used in this study. From the analysis of the urban-runoff processes in small urban area with the progress of urbanization, the following conclusions is obtained. It is found in the results of calculated geographical parameter that peak time is quickened by 15∼35 minutes rather than the urbanization before. Also, in the analysis of the peak rate of runoff, the peak flow rise by 60 % than the urbanization before.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.182-182
• /
• 2012

Plasma etching is used in various semiconductor processing steps. In plasma etcher, optical- emission spectroscopy (OES) is widely used for in-situ endpoint detection. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. Because of these problems, the object is to investigate the suitability of using plasma impedance monitoring (PIM) and self plasma optical emission spectrocopy (SPOES) with statistical approach for in-situ endpoint detection. The endpoint was determined by impedance signal variation from I-V monitor (VI probe) and optical emission signal from SPOES. However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ and SiNx layers are etched by fluorocarbon on inductive coupled plasma (ICP) etcher, if the proportion of $SiO_2$ and SiNx area on Si wafer are small. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance monitoring is compared with optical emission spectroscopy.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.17 no.3
• /
• pp.458-464
• /
• 2017

A magnetic tunnel junction (MTJ) based ternary content addressable memory (TCAM) is proposed which provides non-volatility. A unit cell of the TCAM has two MTJ's and 4.875 transistors, which allows the realization of TCAM in a small area. The equivalent resistance of parallel connected multiple unit cells is compared with the equivalent resistance of parallel connected multiple reference resistance, which provides the averaging effect of the variations of device characteristics. This averaging effect renders the proposed TCAM to be variation-tolerant. Using 65-nm CMOS model parameters, the operation of the proposed TCAM has been evaluated including the Monte-Carlo simulated variations of the device characteristics, the supply voltage variation, and the temperature variation. With the tunneling magnetoresistance ratio (TMR) of 1.5 and all the variations being included, the error probability of the search operation is found to be smaller than 0.033-%.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.32 no.3
• /
• pp.56-66
• /
• 1990

To investigate the status of irrigation water use and the degree of repeated use of irrigation water, observations for water balance analysis were made during the irrigation periods in 1986 and 1987 crop year. The total area of studied site is 1,441 ha. The site is a major portion of Jedaecheon basin which is located in Bubuk-myeon, Miryang-gun, Gyeongnam Province. The studied area was subdivided into six small blocks. The water balance analysis for these subdivided blocks were carried out considering characteristics of each block. Obtained results are as follow: 1.In mountainous sloppy paddy area(less than 7% slope), the surface inflow was 5A mm/day in average that is one third of the surface inflow into plain paddy area ; 16.7 mm/day. 2.The surface inflows at the vegetative stage and the ripening stage were 15.5 mm/day and 10.4 mm/day, respectively. Those figures were larger than the actual consumptive use at respective same stages ; 13.3 mm/day and 9.2 mm/day, respectively. Whereas, the surface inflow at generative stage was 12.5 mm/day which was less than 14.0 mm/day ; the actual consumptive use. 3.The range of the variation of water storage term was 1 mm/day. This means that there were no change in depth of ponded water on paddy fields. The relationship between the variation of water storage(AS) and the variation of ground water table(H) could be expressed as follow: : AS=0.14H+0.26 4.The ground water inflow: into the transition region ; paddy fields which are located continuously from the mountainous area to the plain area, was larger than the out flow from this region, in general. Rowever, in the plain region where the ground water utilization was predominant, the ground water outflow from this region was larger than inflow: to this region. The relationship between the ground water flow(G2- G1) and the consumptive use in large paddy area(D1-D2) could be expressed as follow: (G2-G1) =0.95(D1-D2) -3.79

• Economic and Environmental Geology
• /
• v.22 no.3
• /
• pp.207-219
• /
• 1989

Eight under 2 micron size fractions of the montmorillonite from Jugjeonri area, Gyeongsanbug-do, were studied and then this result has been compared with data from Yongdongri area. Montmorillonites occurring at the same stratigraphic horizon in each area show limited variation in chemical composition, but shows some degree of differences in exchangeable cation compositions and total layer charges of montmorillonites from Jugjeonri to Yongdongri area. In general, samples from Jugjeonri show higher amount of exchangeable Na and layer charge due to relatively higher substitution of Mg for Al in octahedral sites than those from Yongdongri area. But Their dehydroxylation endothermic peaks of the samples from both areas are abnormal type with a small range of variation of peak temperature. This variation seems to reflect tetrahedral substitution of AI for Si for samples from Yongdongri whereas samples from Jugjeonri do not show shuch a tendency. However, samples from Jugjeonri proved to be relatively higher dehydroxylation peak temperatures than those of the other. DSC data for sample from Jugjeonri also show that divalent-cation saturated montmorillonite have relatively a higher endothermic heat capacities than monovalent-cation saturated one as shown in previous work. Two different morphologies of montmorillonites, honeycomb structure and closely packed intergrowth, by SEM were observed in samples from both areas but the later one is common. The scalloped type is relatively abundant in the sample from Yongdongri than the other. The dominant habit by TEM are irregularly shaped foliated aggregates and platy shaped particles. In general, foliated aggregates which are easy to disperse are relatively abundant in the samples from Jugjeon compared with those from Yongdongri area.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.255-255
• /
• 2022

• Electrical & Electronic Materials
• /
• v.9 no.3
• /
• pp.277-283
• /
• 1996

The temperature dependent characteristics of hydrogenerated amorphous silcon thin film transistor (a-Si:H TFT) with a bottom gate of N-Type <100> Si wafer were investigated. Drain current on the hysteresis characteristic curve showed an exponential variation. Hysteresis area of TFT increased with the gate voltage increased and decreased with the small gate voltage. According to the variation of gate voltages, drain current of TFT increased by temperature increase, and hysteresis characteristics mainly depended on the temperature increase. The hysteresis current showed negative characteristics curve over 383K. The hysteresis occurance area and the differences of forward and reverse sweep were increased at the higher temperature. Hysteresis current of I$_{d}$(on/off) ratio decreased at the lower temperature and increased at the higher temperature.e.

• Journal of Korean Society on Water Environment
• /
• v.26 no.4
• /
• pp.654-663
• /
• 2010

Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.