• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.14-21
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• 2016

Many improper development action were performed at subsurface environment, because there were not any definition about subsurface environment in Korea. The purpose of this study was to establich a definition on subsurface environment. Subsurface environment could be divided by subsurface natural environment and subsurface living environment. The soil, groundwater, ecosystems, landscapes, underground space (naturally occurred) were included in subsurface natural environment. And space and facilities used by human were classified as subsurface living environment.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권3호
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• pp.18-26
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• 2017

The increasing frequency of droughts has been increasing the necessity of utilizing subsurface dams as reliable groundwater resources in areas where it is difficult to supply adequate agricultural water using only surface water. In this study, we analyzed the current status and actual conditions of five agricultural subsurface dams as well as the effect of obtaining additional groundwater from subsurface dams operated as one aspect of the sustainable integrated water management system. Based on the construction methods and functions of each subsurface dam, the five subsurface dams are classified into three types such as those that derive water from rivers, those that prevent seawater intrusion, and those that link to a main irrigation canal. The classification is based on various conditions including topography, reservoir location, irrigation facilities, and river and alluvial deposit distributions. Agricultural groundwater upstream of subsurface dams is obtained from four to five radial collector wells. From the study, the total amount of groundwater recovered from the subsurface dam is turned out to be about 29~44% of the total irrigation water demand, which is higher than that of general agricultural groundwater of about 4.6%.

• 한국전자파학회논문지
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• 제18권10호
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• pp.1150-1156
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• 2007

본 논문에서 PCS 및 cellular 망을 이용한 지하 매설물의 원격 관리에 적용이 가능한 지표면 매입형 안테나를 제안하였다. 지표면 매입형 안테나는 원형 패치 안테나를 이용하여 2중 공진이 생기도록 하여, 맨홀 뚜껑과 같은 금속에 삽입하고, 안테나 보호를 위해 몰딩 처리를 하여 제작하였다. 금속체 속에 삽입 및 몰딩으로 인해 안테나의 공진 주파수가 변화하게 되는데, 이것을 고려하여 안테나를 설계하였다. 제작된 안테나의 반사 손실 및 다이폴 안테나와의 상대적인 수신 전력 비교 측정을 통해 제안된 안테나가 PCS 및 cellular망을 이용한 지하 매설물의 원격 관리에 적용이 가능함을 확인하였다.

• International Journal of Safety
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• 제6권2호
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• pp.43-48
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• 2007

We introduced the Excavation One Call System (EOCS) as a pilot system, in Seoul, Korea. The system utilizes the phone and internet to transfer information about digging underground and buried gas pipelines, although currently written forms are used in accordance with the City Gas Business Law. After one year, we evaluated the business model by surveying the excavators and the operators of the gas companies. This paper shows that the EOCS was more effective in preventing the buried gas pipelines from being damaged than the existing method that has to use due form. It also shows that the EOCS was more convenient and cost efficient than the present policies in place. We come to the conclusion that the EOCS should be extended nationwide and gradually include other subsurface facilities.

• 한국물환경학회지
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• 제24권1호
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• pp.107-117
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• 2008

Infiltration facilities are effective instruments to mitigate flood and can increase base runoff in urban watersheds. In order to analyze effects of infiltration trenches physical model experiments were conducted. The physical model facility consists of two soil tanks, artificial rainfall generators, tensiometers, and piezometers. The experiment was conducted by nine times and each case differed in rainfall intensity, rainfall duration and the type of ground surface. Measured quantities in the experiments are as follows: surface runoff, subsurface runoff, trench pipe runoff, groundwater level, water content, etc. The following resulted from the model experiment: The volume of subsurface runoff at trench watershed was maximum 78.3% compared with rainfall. This value is bigger than that of ordinary rate of subsurface runoff, and shows a groundwater recharge effect of trench. The time of runoff passing through the trench became earlier and the volume of runoff became larger with the increase of inflow into the trench, while trench exfiltration into ground became relatively smaller. The results of this study presented above show that infiltration trenches are effective instruments to increase base runoff during dry periods.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.155-163
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• 2003

대덕 원자력시설 주변 지표 토양 환경내 오염물 거동 해석을 위하여 지하수 유동 및 오염물 이동 수치모델을 수립하였다. 수립된 모델을 이용하여 대덕 원자력시설 주변의 지하수 흐름체계를 해석하고 U-234에 대한 농도분포를 계산하였다. 산정 결과 지하수는 부지내 하나로를 중심으로 동쪽 및 동남 방향으로의 흐름이 나타났고, 지표 토양내로 유입된 방사성 물질은 지하수 유동에 의해 같은 방향으로 이동되었다. 대덕 원자력시설로부터 지표로 침적된 방사성 물질의 농도분포를 산정한 바 환경에 미치는 영향은 거의 없는 것으로 나타났다.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.376-380
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• 2006

Temperature distribution measured to estimate the condition of an electrical apparatus is an absolute reference for the apparatus conditions and the difference between the reference temperature and the current temperature. Because of passive thermography, without the external thermal stimulation, the difference in surface temperature between the region of interest and back ground shows that the results can apply only to the estimation or the monitoring for the condition of loose terminal and the overload pertaining to the rise in temperature. However, a thermal diffusion in the active thermography is differently generated by the structure and condition of the surface and subsurface. This paper presents a nondestructive test using this behavior and deals with the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

• 한국환경과학회지
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• 제16권12호
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• pp.1325-1335
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• 2007

The utility of soil-gas surveys is directly proportional to their accuracy in reflecting and representing changes in the subsurface concentrations of source compounds. Passive soil-gas vapor-phase is merely a fractional trace of the source, so, as a matter of convenience, the units used in reporting detection values from EMFLUX surveys are smaller than those employed for source-compound concentrations. According to the Leaking Underground Storage Tank(LUST) Program Annual Report, approximately 16 U.S. million dollars were spent for environmental site investigations at over 1,600 Underground Storage Tank(UST) sites and approximately over 1,000 acres of land was characterized and remediated in the State of Illinois in the year of 2003 alone. The main purpose of this study is to propose an idea to significantly reduce the site investigation cost by utilizing a passive soil-gas survey and conventional intrusive drilling method and to fully define the three dimensional characteristics of subsurface contamination from two industrial drycleaning facilities.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.449-454
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• 2003

The accurate mapping of the basement is one of the most crucial factors in construction of harbour facilities and bridges in the coastal areas. In shallow waters, the seismic reflection method often fails to image the basement geometry beneath the sediment cover in many cases. We present the result of a shallow marine seismic refraction survey using two ships, l2-channel hydrophone arrays deployed on the bottom and a borehole sparker or percussion powder as sources. Velocity structure could be computed by tomography algorithm since more than 6 different source points had been applied for one spread. The comparison of the results of the refraction survey with drilling logs demonstrates remarkable consistency in basement geometry. It thus appears that the refraction method in this study is an efficient and cost-effective way to investigate the basement structure in coastal area, river, and lake.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.280-285
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• 2000

It is very important to evaluate the surface or subsurface microstructure because of their influences on mechanical properties of materials. Surface SH-wave which is horizontally polarized shear wave traveling along near surface and subsurface layer is an attractive technique for material evaluation. The destructive method is widely used for the estimation of material degradation but it has a great difficulty in preparing specimens from in-service industrial facilities. In this study, nondestructive evaluation for degraded structural materials used at high temperature though surface SH-wave method is discussed. 2.25Cr-1Mo steel specimens which were prepared by the isothermal aging heat treatment at $650^{\circ}$ were evaluated though ultrasonic nondestructive evaluation techniques investigating the change of sound velocity, attenuation coefficient and amplitude spectra. In addition, it has verified experimentally the frequency-dependence of attenuation coefficient though wavelet analysis method.