• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.825-843
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• 2009

To prepare for agricultural droughts, the potential discharge to the water supply of irrigation facilities during drought periods is important. Using the MODSIM (Modified SIMYLD) model, water balance networks that consider irrigation facilities were designed for the Geum River Basin, and the potential discharge to the agricultural water supply of irrigation facilities were evaluated by running the model using data for 36 years (1967-2002). It was found that agricultural water deficiencies occurred during the drought years more than in the other years. The agricultural water deficiencies in 1994, 1995, and 2001, the representative drought years, were 745.8 million m$^3$, 661.1 million m$^3$, and 696.8 million m$^3$, respectively. The average potential discharge to the water supply of the sub-basin was 99.1 % in the cases of municipal and industrial water, and 84.4 % in the case of agricultural water. The potential discharge to the water supply in 1994, 1995, and 2001 were 74.8 %, 79.2 %, and 77.9 %, respectively, which are lower than those of the other years' sub-basin average. In the analysis of the contribution of each irrigation facility, the contributions of pumping stations and diversions were calculated as 32.5 %, and of culverts and wells, 4.0 %. During the drought periods, the pumping stations and diversions contributed to a certain level.

• Journal of the korean society of oceanography
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• v.33 no.4
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• pp.146-156
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• 1998

Hydrographic data retrieved in the southwestern part of the East Sea in 1992-1993 were analyzed to investigate the probability of southward intrusion of the East Sea Intermediate Water (ESIW) into the Ulleung Basin. The ESIW showed the ranges of 1 to 4$^{\circ}$C in potential temperature, 33.80-34.06 psu in salinity, and 26.9-27.3 kg/m$^3$ in potential density (${\sigma}$$_{\theta}$). The mean depth occupied by the ESIW was 170 m, where the characteristic values of the above three were 2.64$^{\circ}$C , 34.02 psu, and 27.13 kg/m$^3$, respectively. One of the most prominent features of the ESIW was that its salinity changed not only seasonally but also interannually. It was low in summer and high in winter. The salinity within the isopycnal layer of 26.9-27.3 kg/m$^3$ was closely related with the potential vorticity (${\rho}$$_{\theta}^{-1}$ f ${\varrho}$${\rho}_{\theta}$/${\varrho}$z), being in direct proportion to the salinity. This implies that the low-salinity water was thicker than the high-salinity water. The flow path of the ESIW was investigated by tracking the low-salinity or the low-potential vorticity water and by referring to acceleration potential. Careful analysis of the flow path proves that the ESIW intrudes from the north between the Korean coast and Ulleung Island into the Ulleung Basin in summer. Existence of the high-potential vorticity water in the Ulleung Basin is associated with the interruption of the inflow of low-salinity water.

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.55-57
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• 2005

Along with the development of the industrial society, as the transportation of water which is the indirect capital of society and petroleum, gas, etc used as energy sources is rapidly increased. the underground material is being expanded. Like this, the pipes laid under the ground not only bring the corrosion to the land circumstances to reduce the life of the pipes, but also raise the social problem of leakage accidents and the economic loss by Pin Hole. By reason of this, for the purpose of protecting the corrosion of the underground material, we are constructing and operating the electrolytic protection facilities. In case of a region of which specific resistance is high, however, we are not keeping proper protection potential(that is -850mV) to get protection effects. In this study, for the water pipes that under-voltage phenomena occur in the protection potential, we made a spot survey on the under-voltage section and normal-voltage section, compared, analyzed each of the contents and examined the under-voltage causes of the protection potential.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.6
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• pp.521-528
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• 2005

This study has been conducted to investigate the potential energy reserve amount of river water as energy resource with useful temperature difference. Since the river water temperature is one of the primary parameters deciding the potential amount of river water energy reserve amount, the climate change effects on it are critically important. In this study, the heat exchange processes and the inter-relationship between the air temperature and river water temperature have been theoretically analyzed. Based on the present study, the potential energy reserve of river water is calculated to amount to 192,000 Tcal/year. Among this, it is estimated that approximately 2,000 Tcal/year can be directly utilized for heat pump energy sources.

• Bulletin of the Society of Naval Architects of Korea
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• v.19 no.1
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• pp.23-32
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• 1982

Herein the motion of a freely-floating sphere in a water of finite depth is analysed within the framework of a linear potential theory. A velocity potential describing fluid motion is generated by distributing pulsating sources and dipoles on the immersed surface of the sphere, without introducing an inner flow model. The potential becomes the solution of an integral equation of Fredholm's second type. In the light of the vertical axisymmetry of the flow, surface integrals reduce to line integrals, which are approximated by summation of the products of the integrand and the length of segments along the contour. Following this computational scheme the diffraction potential and the radiation potential are determined from the same algorithm of solving a set of simultaneous linear equations. Upon knowing values of the potentials hydrodynamic forces such as added mass, hydrodynamic damping and wave exciting forces are evaluated by the integrating pressure over the immersed surface of the sphere. It is found in the case of finite water depth that the hydrodynamic forces are much different from the corresponding ones in deep water. Accordingly motion response of the sphere in a water of finite depth displays a particular behavior both in a amplitude and phase.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.4
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• pp.75-80
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• 1995

It is important to estimate the possibility of recovery in physiologically damaged woody plant. It is suggested that C.E.R(cambial electrical resistance) might be a useful method to predict the permanent wilting point. D/A and A/D converter can be used to measure the C.E.R and it took only 10-20 msec for a measurement and the values were stable during this study. A computer could be used for the continual measurement of C.E.R. There were very big daily changes of C.E.R. was changed according to the changes of indoor temperature, but the phase was slightly different. It is reasoned that daily changes in C.E.R. is induced by the changes of water potential and cambial thickness. It was difficult to detect the changes of C.E.R. caused by changes in soil moisture under high soil water potential. Under low soil water potential, the changes in soil moisture under high soil water potential. Under low soil water potential, the changes of C.E.R. can be detected. After wilting, C.E.R. is increased very rapidly. When C.E.R. is not decreased by watering, it will be permanent wilting point. But it takes several days to confirm the permanent wilting point. To predict the possibility of recovery from wilting, the values of C.E.R. have no meaning. But the changes of C.E.R. are significant. Therefore we can predict the permant wilting point in woody plant by monitoring the change of C.E.R. by the computer.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.61-70
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• 2003

The size distribution of the free water paths between earlywood and latewood for six species in the heartwood of softwoods was estimated from the amount of dehydrated free water under various centrifugal fields, such as 2,200, 3,300, 4,800 and 6,900 rpm. The centrifugal method is based on the concept that water movement occurs by the balance of centrifugal force and water potential by meniscus. Water stops where the pressure differential is zero. In the centrifugal field, only two factors affect water movement in wood, that is, centrifugal force and water potential. Also, the water permeability was evaluated from the relationship between the water saturation ratio after the centrifugal treatment and the measure of water potential in specimen. The results showed that Cryptpmeria japonica had clear peaks at 0.70 ㎛ in earlywood and at 0.50 ㎛ in latewood. Tsuga sieboldii and Larix kaemferi had peaks at 0.50 and 0.30 ㎛ in both earlywood and latewood, respectively. Abies firma showed peaks at 0.70 ㎛ in earlywood and at 0.30 ㎛ in latewood. The water permeability of earlywood was higer than that of latewood for all softwoods except Pseudotsuga menziesii.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.98-105
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• 1983

Differences in fertilizer responses of Chinese cabbage to soil water status were investigated in a field experiment. The growth pattern, water use, nutrient uptake, apparent efficiency of fertilizer and yield were analyzed under the 4-different fertilizer levels (N-P-K rate, kg/10a: 0-0-0 Fo, 11.5-10-12.5 Fo.5, 23-30-25 F1.0, 34.5-30-37.5 F1.5 and under the 4-different soil water status levels (non irrigated plot Mo, -0.1 to -1.0 bars M1, -0.1 to -0.5 bars M2, -0.1 to -0.2 bars M3). The soil was Bonryang sandy loam in the experimental farm of the Institute of Agricultural Sciences, Suweon. The growth and yield responses to the fertilizer levels showed a large difference between F0 and F0.5 but little differences were recognized between F0.5, F1.0 and F1.5 when the soil water potentials at 20-cm soil depth were lower than -2.0 bar. Under the well irrigated soil conditions, M2, and M3, the growth and yield responses to the fertilizer levels were significantly increased and the nutrient requirements were increased as well. The total uptake of nutrients decreased as the fertilizer amounts increased when the soil water potentials were low, while the total uptake of nutrients increased when the soil water potentials were high. Therefore, in considering nutrient availability of the applied fertilizers, the soil water status should be taken into account.

• Korean Journal Plant Pathology
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• v.3 no.1
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• pp.13-16
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• 1987

Infection rate of chestnut tree by Botryosphaeria(Dothiorella) dathidea was about $10\%$ at Gapyung area. disease symptom of chestnut did not appear in October but appeared in November, showing $50\%$ in May in ext year. B. dothidea was more pathogenic to chestnut than did Catinula sp. and Fusicoccum sp. B. dothidea uses soft rot, but Catinula sp. and Fusicoccum sp. causes dry rot. Mycelial growth of B. dothidea was optimal at $28^{\circ}C$. Mycelial growth was stimulated when water potential decreased from -2 bars to -12 bars and declined from -12 bars to -60 bars.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.349-354
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• 2005

Recently, there are many equipment of electricity, electronics, and communication which need to grounding in the building. When the electric current flows into a certain grounding system in the same building, the potential rise of other grounding system is possible to be affected by its potential rise. This potential interference was affected by the surface potential, it is deeply related whit the electrode shape. In this paper, basic formula is deduced on the basis of both electrodes surface potential of grounding electrode in a source of the potential interference and groundidng electrode which receive the potential interference. Therefore the degree of potential interference as multiple groundidng electrode can be verified the simulated results by means of the simple model in advance. This is for investigating the grounding resistance of grounding electrodes, the experiment was performed with model-scale of the grounding system and the scaled model grounding system was to this experiment using a water tank of a stainless steel-hemisphere shape. since mesh electrodes have been widely in the general building, we're tried to analyze that this water tank model and it's simulation as well.