• Title/Summary/Keyword: shallow depth

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ADI Finite Difference Method of Linear Shallow Water Wave Equation (선형 천수방탁식의 ADI 유한차분법)

  • 이종찬;서승남
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.4 no.2
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    • pp.108-120
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    • 1992
  • An ADI model for linearized shallow water equation is modified using the method of factorization. In order to show its validity. the computational results are compared both with the analytical solution and with those from existing models, for a rectangualr domain with constant and varying amplitudes at the open boundary. It is shown the accuracy of numerical solutions depends on the size of time step. depth and bottom friction. The modified ADI model is shown to be superior to the existing models such as Leendertse (1971). Butler (1980) and Sheng (1983).

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The Application of Geophysical Prospecting for Detecting Substructure and Boundary of Layer In Limestone Area (석회암 지역의 기반암 및 경계면 조사를 위한 지구물리 탐사법의 적용)

  • Suh, Beak-Su;Lee, Duk-Jae
    • Journal of Industrial Technology
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    • v.20 no.A
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    • pp.285-293
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    • 2000
  • In 1970's, the analysis of shallow substructure was the interests of geological engineering and environmental problems. And seismic refraction method was applied to detect those structures. From 1980's, digital electric industry is rapidly developed and high resolution prospecting equipment is supplied. And seismic reflection method is applied to achieve various data gathering and data analysis. In this study, geophysical prospecting method is applied to calculate the basic data of limestone yield production. Seismic shallow reflection method is used to detect the depth of bedrock and electrical resistivity method is used to detect of limestone layer boundary.

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Ultra Shallow Junction wish Source/Drain Fabricated by Excimer Laser Annealing and realized sub-50nm n-MOSFET (엑시머 레이져를 이용한 극히 얕은 접합과 소스, 드레인의 형성과 50nm 이하의 극미세 n-MOSFET의 제작)

  • 정은식;배지철;이용재
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.562-565
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    • 2001
  • In this paper, novel device structures in order to realize ultra fast and ultra small silicon devices are investigated using ultra-high vacuum chemical vapor deposition(UHVCVD) and Excimer Laser Annealing (ELA). Based on these fundamental technologies for the deep sub-micron device, high speed and low power devices can be fabricated. These junction formation technologies based on damage-free process for replacing of low energy ion implantation involve solid phase diffusion and vapor phase diffusion. As a result, ultra shallow junction depths by ELA are analyzed to 10~20nm for arsenic dosage(2${\times}$10$\_$14//$\textrm{cm}^2$), exciter laser source(λ=248nm) is KrF, and sheet resistances are measured to 1k$\Omega$/$\square$ at junction depth of 15nm and realized sub-50nm n-MOSFET.

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The Characteristics of Circulation in the Coastal Area of Jeju Harbor Using the Three Dimensional Ocean Circulation Model (3차원 해수유동모델에 의한 제주항 연안해역의 해수순환 특성)

  • Yang, Tai-Hoek;Yang, Sung-Kee
    • Journal of Environmental Science International
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    • v.20 no.6
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    • pp.679-686
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    • 2011
  • The characteristics of circulation in the coastal area of Jeju Harbor in Korea was examined using the Princeton Ocean Model(POM) with a sigma coordinate system. The result of numerical analysis well corresponded to the observed current data. The velocity at offshore was stronger compared to coastal area during the both period of in maximum flood and maximum ebb of spring tide. According to mean wind velocity, the tidal velocity at the shallow area of Jocheon was slightly increasing during maximum ebb. The effect of wind on the circulation was stronger in shallow area and showed rapid change with depth.

A Design Evaluation of Strained Si-SiGe on Insulator (SSOI) Based Sub-50 nm nMOSFETs

  • Nawaz, Muhammad;Ostling, Mikael
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.5 no.2
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    • pp.136-147
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    • 2005
  • A theoretical design evaluation based on a hydrodynamic transport simulation of strained Si-SiGe on insulator (SSOI) type nMOSFETs is reported. Although, the net performance improvement is quite limited by the short channel effects, simulation results clearly show that the strained Si-SiGe type nMOSFETs are well-suited for gate lengths down to 20 nm. Simulation results show that the improvement in the transconductance with decreasing gate length is limited by the long-range Coulomb scattering. An influence of lateral and vertical diffusion of shallow dopants in the source/drain extension regions on the device performance (i.e., threshold voltage shift, subthreshold slope, current drivability and transconductance) is quantitatively assessed. An optimum layer thickness ($t_{si}$ of 5 and $t_{sg}$ of 10 nm) with shallow Junction depth (5-10 nm) and controlled lateral diffusion with steep doping gradient is needed to realize the sub-50 nm gate strained Si-SiGe type nMOSFETs.

A Study on Upstream Waves for an Advancing Arbitrary Hull Shape in Restricted Water Channel

  • Kim, Sung-Young;Lee, Young-Gill
    • Journal of Ship and Ocean Technology
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    • v.4 no.2
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    • pp.24-37
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    • 2000
  • The purpose of this paper is to study the upstream waves in front of an advancing arbitrary hull shape in a restricted water channel. Conventionally, in a restricted water channel, shallow water effects are amplified because of the finite water depth and width. When the effects of shallow water and the restricted channel width are severe, upstream waves propagate forward from the fore-body of the advancing hull. In this study, numerical simulations are carried out for the relevant analysis of the flow phenomena by the draft variation of advancing hull in a restricted water channel. Numerical simulations are done with a finite-difference method based on the MAC scheme in a rectangular grid system.

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Soft Ground Investigations Using Small Loop EM (소형루프 전자탐사법을 이용한 연약지반 조사)

  • Kim, Ki-Ju;Cho, In-Ky;Lim, Jin-Taik;Kyeung, Keu-Ha;Kim, Bong-Chan
    • 한국지구물리탐사학회:학술대회논문집
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    • 2007.06a
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    • pp.245-250
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    • 2007
  • The small loop EM method is a fast and convenient geophysical tool which can give shallow subsurface resistivity distribution. It can be a useful alternative of resistivity method in conductive environment. We applied the multi-frequency small loop EM method for the investigation of a soft ground landfill site which was constructed on a tideland since the resistivity of the survey area is extremely low. 3D resistivity distribution was obtained by merging 1D inversion results and shallow subsurface structure can be interpreted. By comparing the result with the drilling log and measured soil resistivity sampled at 16 drill holes, we can get lot of information such as groundwater level, thickness of landfill, salinity distribution, depth to the basement and etc.

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Formation of the Shallow $p^+$ -n Junction by As-Preamorphization Method and Characterization (비소 비정질화 방법에 의한 얕은 $p^+$-n 접합의 형성과 특성분석)

  • Sang Jik Kwon
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.11
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    • pp.113-121
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    • 1993
  • In the formation of the shallow p$^{+}$-n junction, the preamorphization method by As$^{+}$ ions was applied in order to avoid the boron channeling effect which is occured during the B$^{+}$ implantation especially with low energy. By As$^{+}$ pre-implant with 60KeV energy and 2*10$^{14}$ cm$^{-2}$ dose, the channelinf of B$^{+}$ ions implanted with 10keV/1.5*10$^{14}$ cm$^{-2}$ can be avoded completely. After the RTA of 1050.deg. C and 10sec, the junction depth was 0.14.mu.m, the leakage current was 20nA/cm$^{2}$(at-5V bias) and the sheet resistance was 107.OMEGA./ㅁ. And the preamorphized Si layer was changed into the perfect crystal si after the RTA.r the RTA.

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A study of the pollution of ground water in the basin of the river Baem Nae Chun, Sorae-Myun, Shihoong-gon, Kyonggi-Do, Korea (경기도 시흥군 소래면 뱀내하천 유역의 지하수 오염에 관한 연구)

  • 김윤종;정봉일
    • Water for future
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    • v.6 no.2
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    • pp.19-29
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    • 1973
  • The progressive contamination of water resulted from man's activity and the use of fertilizers is not restricted only to surface water, but also the shallow groundwater is affected. This type of groundwater contamination is mainly restricted to areas composed of permeable, nonconsolidated sediments forming a shallow aquifer. The chloride and the sulfate resulted from man's activity and the use of fertilizers were measured to study the variations of the groundwater contamination. In general, (1) When water level rises, the rate of groundwater contamination becomes less and when water level declines, the rate of contamination is increased. (2) The highly contaminated season is the early-summer and the less contaminated season is the winter or after rainy season. (3) The groundwater in weathering zone without covering layer. (4) The degree of contamination of wells is increased with the increase of well depth and lowing the water table, because of increasing contaminated water from enlargement of the area of influence of the well.

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Shallow P+-n Junction Formation and the Design of Boron Diffusion Simulator (박막 P+-n 접합 형성과 보론 확산 시뮬레이터 설계)

  • 김재영;이충근;김보라;홍신남
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.7
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    • pp.708-712
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    • 2004
  • Shallow $p^+-n$ junctions were formed by ion implantation and dual-step annealing processes. The dopant implantation was performed into the crystalline substrates using BF$_2$ ions. The annealing was performed with a rapid thermal processor and a furnace. FA+RTA annealing sequence exhibited better junction characteristics than RTA+FA thermal cycle from the viewpoint of junction depth and sheet resistance. A new simulator is designed to model boron diffusion in silicon. The model which is used in this simulator takes into account nonequilibrium diffusion, reactions of point defects, and defect-dopant pairs considering their charge states, and the dopant inactivation by introducing a boron clustering reaction. Using initial conditions and boundary conditions, coupled diffusion equations are solved successfully. The simulator reproduced experimental data successfully.