• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.99-109
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• 1999

In the case of domestic general waste landfills, cumulated leachate level is often formed in the landfill due to the waste of high moisture content and it becomes important to characterize the hydraulic properties of the disposed waste. Although many hydrologic studies have been peformed for leachate barriers and pheriperal subsurface environments, few studies have been done to investigate the hydraulic property of the disposed waste and cover soils and to analyse the leachate flow behavior within landfills. In this paper, the geotechnical properties of the waste and buried cover soils are identified through the field experiment including pumping and slug tests. The results of various tests show that the field density of the cover soils is somewhat higher than the maximum laboratory density of cover soils and the vertical flow of leachate and gas in the landfill is prevented by the buried cover soils. The hydraulic conductivities of field pumping test and slug tests are well matched and stayed in the range of hydraulic conductivities of well compacted wastes in the literature.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.32-37
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• 1998

In this paper, the role of intermediate cover soils with respect to the leachate and gas flow is investigated from various field investigations and the hydraulic conductivity of the disposed waste is obtained using pumping and slug tests. From the results of field investigations, it was found that the flow of leachate and gas is prevented by the buried cover soils. The hydraulic conductivities of field pumping test and slug tests are well matched and stayed in the range of hydraulic conductivities of well compacted wastes in the literature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.210-215
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• 1994

In the CMOS device, Counter doping is needed to adjust threshold voltage because of the difference between n-MOSFET and p-MOSFET well doping concentration when n+ polysilicon gate is used. Therefore buried channel is formed in the p-channel MOSFET degrading properties. So well doping concentration and doping condition should be considered in fabrication process and device design. Here we are to extract the initial process condition using simulation and fabricate p-MOSFET device and then compare the subthreshold characteristics of simulated and fabricated device.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1292-1297
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• 1997

본 연구에서는 latch-up 개선책의 일환으로 개발중인 매립층을 갖는 retrograde well의 형성기술과 더불어 공정 단순화를 목적으로 개발된 BILLI (Buried Implanted Layer for Lateral Isolation) well 구조[1]에 대한 공정 유기 결함을 분석하고 그에 의한 소자 열화 특성을 분석 하였으며 그 개선책을 제시 하고자 하였다. 매립층 형성에 의한 유기결함은 접합 누설전류와 Gate oxide 신뢰성을 열화 시켰으나 이온주입 후 $1000^{\circ}C$ 이상의 온도에서 10sec 정도의 RTP anneal에 의해 그 소자 특성이 개선되며 표면 결함이 감소함을 알 수 있었다.

• Conservation Science in Museum
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• v.6
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• pp.67-71
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• 2005

We conduct the conservation treatment for the wooden well bucket excavated from civilian remains in Siji-Dong, Daegu. This bucket was in very poor condition, having been buried for a long time; thus, cetyl alcohol was used for the conservation. After replacing the water inside the wooden material with alcohol, the density of the cetyl alcohol was increased by 20, 40, 60, and 80% and immersed for two weeks at each step. After completing the immersion procedure, the remaining cetyl alcohol was removed, and the bucket, dried under normal atmosphere.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.217-220
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• 2000

This paper describes the application of a neural network based adaptive line enhancer (ALE) for enhancement of the weak QRS complex corrupted with background noise. Modified fully-connected recurrent neural network is used as a nonlinear adaptive filter in the ALE. The connecting weights between network nodes as well as the parameters of the node activation function are updated at each iteration using the gradient descent algorithm. The real ECG signal buried with moderate and severe background noise is applied to the ALE. Simulation results show that the neural network based ALE performs well the enhancement of the QRS complex from noisy ECG signals.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.10
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• pp.821-829
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• 1991

In this paper, a BICMOS technology that has CMOS devices for digital application and bipolar devices for high voltage (80V) analog applications is presented. Basic concept to design BICMOS device is simple process technology without making too many performance trade-offs. The base line process is poly gate p-well CMOS process and three additional masking steps are added to improve bipolar characteristics. The key ingredients of bipolar integration are n+ buried layer process, up/down isolation process and p-well base process. The bipolar base region is formed simultaneously with the region of CMOS p-well area to reduce mask and heat cycle steps. As a result, hFE value of NPN bipolar transistor is 100-150(Ic=1mA). Collector resistance value is 138 ohm in case of bent type collector structure. Breakdown voltage of BVebo, BVcbo and BVceo are 21V, 115V and78V respectively. Threshold voltage is ${\pm}$1.0V for NMOS and PMOS transistor. Breakdown voltage of NMOS and PMOS transistor is obtained 22V and 19V respectively. 41 stage CMOS ring oscillator has 0.8ns delay time.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.588-595
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• 2008

Recently, it is caused by environment change that is increased the number of lightning occurrence and the strength of lightning current is coming to be strong little by little. The performance of grounding system depends on how to construct. Specially the common grounding systems which uses the buried earth cable must be constructed by very well qualities because it is difficult to measure earth resistance and to manage the buried earth cable. Common grounding systems and independence grounding systems could be composed different. Against railway signalling equipment which like this is used from the environment lower part which is various it presents a standard grounding systems, and very it is hard job. We will present improvement through this paper that review grounding systems configuration condition of railway signalling equipment.

• The Korean Journal of Quaternary Research
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• v.25 no.1
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• pp.31-39
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• 2011

Phytolith of soil in earthenware buried in the wooden chamber tombs at the archaeological site in Hwangseong-dong, Gyeongju along Hyeongsan River are analyzed. The study area has adjoined the seat of government during approximately thousand years in Shilla Dynasty and can be regarded as being closely related to the agricultural activities using the floodplains of Hyeongsan River. By the analytical results, Phragmites, Paniceae and Andropogoneae as well as Oryza sativa are found in the lower horizons, indicating the agricultural activities in the nearby areas. It is suggested for understanding the use of earthenware that the comparisons of buried soils in the site and soils in the earthenware and analysis on the macro plant fossils of soil in the earthenware are needed.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.168-179
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• 2022

Microbiologically Influenced Corrosion (MIC) occurring in underground buried pipes of API 5L X65 steel was investigated. MIC is a corrosion phenomenon caused by microorganisms in soil; it affects steel materials in wet atmosphere. The microstructure and mechanical properties resulting from MIC were analyzed by OM, SEM/EDS, and mapping. Corrosion of pipe cross section was composed of ① surface film, ② iron oxide, and ③ surface/internal microbial corrosive by-product similar to surface corrosion pattern. The surface film is an area where concentrations of C/O components are on average 65 %/16 %; the main components of Fe Oxide were measured and found to be 48Fe-42O. The MIC area is divided into surface and inner areas, where high concentrations of N of 6 %/5 % are detected, respectively, in addition to the C/O component. The high concentration of C/O components observed on pipe surfaces and cross sections is considered to be MIC due to the various bacteria present. It is assumed that this is related to the heat-shrinkable sheet, which is a corrosion-resistant coating layer that becomes the MIC by-product component. The MIC generated on the pipe surface and cross section is inferred to have a high concentration of N components. High concentrations of N components occur frequently on surface and inner regions; these regions were investigated and Na/Mg/Ca basic substances were found to have accumulated as well. Therefore, it is presumed that the corrosion of buried pipes is due to the MIC of the NRB (nitrate reducing bacteria) reaction in the soil.