• Journal of the Korean Institute of Gas
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• v.22 no.5
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• pp.100-106
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• 2018

pressure buried pipes in domestic industrial estate have many long-term use pipes, Toxic, flammable, Inflammable, etc. as well as a variety of toxic chemicals are embedded in a complex be buried, A high level of safety management is required as it can damage other pipes installed nearby in the event of accidents such as various external interference. Therefore, in this study, the safety management practices of high-pressure gas distribution and urban gas distribution are utilized to derive efficient safety management methods for high-pressure gas installation piping through in-depth comparative analysis.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.167-183
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• 2013

Methods for estimating structural reliability using probability ideas are well established. When the residual ultimate strength of a buried pipeline is exceeded the limit, breakage becomes imminent and the overall reliability of the pipe distribution network is reduced. This paper is concerned with estimating structural failure of underground flexible pipes due to corrosion induced excessive deflection, buckling, wall thrust and bending stress subject to externally applied loading. With changes of pipe wall thickness due to corrosion, the moment of inertia and the cross-sectional area of pipe wall are directly changed with time. Consequently, the chance of survival or the reliability of the pipe material is decreased over time. One numerical example has been presented for a buried steel pipe to predict the probability of failure using Hasofer-Lind and Rackwitz-Fiessler algorithm and Monte Carlo simulation. Then the parametric study and sensitivity analysis have been conducted on the reliability of pipeline with different influencing factors, e.g. pipe thickness, diameter, backfill height etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.415-419
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• 1999

Many bipolar logic circuit of conventional occurred problem of speed delay according to deep saturation state of vertical NPN Transistor. In order to remove minority carries of the base region at changing signal in conventional bipolar logic circuit, we made transistor which is composed of NPN transistor shortened buried layer under the Base region, PNP transistor which is merged in base, epi layer and substrate. Also the Ring-Oscillator for measuring transmission time-delay per gate was designed as well. The structure of Gate consists of the vertical NPN Transistor, substrate and Merged PNP Transistor. In the result, we fount that tarriers which are coming into intrinsic Base from Emitter and the portion of edge are relatively a lot, so those make Base currents a lot and Gain is low with a few of collector currents because of cutting the buried layer of collector of conventional junction area. Merged PNP Transistor's currents are low because Base width is wide and the difference of Emitter's density and Base's density is small. we get amplitude of logic voltage of 200mv, the minimum of transmission delay-time of 211nS, and the minimum of transmission delay-time per gate of 7.26nS in AC characteristic output of Ring-Oscillator connected Gate.

• Electronics and Telecommunications Trends
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• v.5 no.1
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• pp.55-70
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• 1990

SIMOX SOI is known to be one of the most useful technologies for fabrications of new generation ULSI devices. This paper describes the current status of SIMOX SOI technology for ULSI applications. The SIMOX wafer is vertically composed of buried oxide layer and silicon epitaxial layer on top of the silicon substrate. The buried oxide layer is used for the vertical isolation of devices The oxide layer is formed by high energy ion implantation of high dose oxygen into the silicon wafer, followed by high temperature annealing. SIMOX-based CMOS fabrication is transparent to the conventional IC processing steps without well formation. Furthermore, thin film CMOX/SIMOX can overcome the technological limitations which encountered in submicron bulk-based CMOS devices, i.e., soft-error rate, subthreshold slope, threshold voltage roll-off, and hot electron degradation can be improved. SIMOX-based bipolar devices are expected to have high density which comparable to the CMOX circuits. Radiation hardness properties of SIMOX SOI extend its application fields to space and military devices, since military ICs should be operational in radiation-hardened and harsh environments. The cost of SIMOX wafer preparation is high at present, but it is expected to reduce as volume increases. Recent studies about SIMOX SOI technology have demonstrated that the performance of the SIMOX-based submicron devices is superior to the circuits using the bulk silicon.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.553-562
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• 2008

A remediation technique for buried pipeline system subject to permanent ground deformation is proposed. Specifically, EPS (expanded polystyrene) geofoam blocks are used as low density backfill, thereby reducing soil restraint and pipeline strains. In order to evaluate this remediation technique, a series of 12 centrifuge model tests with HDPE pipe were performed. The amount or spatial extent of the low density backfill was varied, as well as the orientation of the pipe with respect to the fault offset. Specifically, in the $-63.5^{\circ}$ test, the orientation was such that the pipe was placed in flexure and axial tension. The $-85^{\circ}$ orientation placed the pipe mainly in flexure. In all cases, the behavior of the remediated pipe was compared to that for the unremediated pipe. The geofoam backfill was successful in improving pipe behavior for two of the three pipe/fault orientations. However, for the $60^{\circ}$ orientation, the pipe buckled in compression irrespective of the geofoam backfill.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.803-808
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• 2003

Several dielectric pipes buried in the lossy half space are reconstructed from the scattered fields measured along the interface between the air and the lossy ground. Iterative inversion method by using the hybrid optimization algorithm combining the genetic and the Levenberg-Marquardt algorithm enables us to find the positions, the sizes, and the medium parameters such as the permittivities and the conductivities of the buried pipes as well as those of the background lossy half space even when the dielectric pipes are close together. Illposedness of the inversion caused by the errors in the measured scattered fields are regularized by filtering the evanescent modes of the scattered fields out.

• Corrosion Science and Technology
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• v.11 no.2
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• pp.56-64
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• 2012

Factors affecting corrosion of stainless steels such as pH, oxidation and redox potential (ORP), soil resistivity, water content of soil, chloride ion concentration, bacteria activity, and corrosion potential have been investigated using soil analysis, bacterial analysis, surfacial analysis, and analysis of corrosion potentials of several stainless steels buried in 8 sites of Seoul metropolitan for one year. Corrosion potential was affected by occurrance of corrosion as well as bacteria activity but the behavior of corrosion potential with time is different depending on occurrance of corrosion and bacteria activity. The main factor affecting corrosion of stainless steels in soil is level of chloride ion concentration which is also a main factor affecting corrosion of stainless steels in chloride containing drinkable water. Furthermore, guideline of stainless steels in drinkable water is concluded to be applicable to that in soil by the results from surfacial analysis.

• Computers and Concrete
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• v.24 no.5
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• pp.445-452
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• 2019

In this paper, dynamic stress, strain and deflection analysis of concrete pipes conveying nanoparticles-water under the seismic load are studied. The pipe is buried in the soil which is modeled by spring and damper elements. The Navier-Stokes equation is used for obtaining the force induced by the fluid and the mixture rule is utilized for considering the effect of nanoparticles. Based on refined two variables shear deformation theory of shells, the pipe is simulated and the equations of motion are derived based on energy method. The Galerkin and Newmark methods are utilized for calculating the dynamic stress, strain and deflection of the concrete pipe. The influences of internal fluid, nanoparticles volume percent, soil medium and damping of it as well as length to diameter ratio of the pipe are shown on the dynamic stress, strain and displacement of the pipe. The results show that with enhancing the nanoparticles volume percent, the dynamic stress, strain and deflection decrease.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.86-90
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• 1992

We have studied the characteristics of n-and p-channel FETs with submicron channel length fabricated by twin-well process. Threshold voltage variation and potential distribution with channel ion implantation conditions and impurity profile of n-and p-channel region wee simulated using SUPREM-II and MINIMOS 4.0 simulater, P-channel FET had buried-channel in the depth of 0.15 $\mu\textrm{m}$ from surface by counter-doped boron ion implantation for threshold voltage adjustment. As a result of device measurement, we have obtained good drain saturation characteristics for 3.3 [V] opreation, minimized short channel effect with threshold voltage shift below 0.2[V], high punchthrough and breakdown voltage above 10[V] and low subthreshold value.

• 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.