• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.134-142
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• 1996

The epi-CoSi$_{2}$ layer was formed by alloying a Co(120$\AA$)/Ti(50$\AA$) bilayer. In addition, the ultra shallow p$^{+}$n junction of which depth is about not more than 40nm at the background concentration, 10$^{18}$atoms/cm$^{3}$ could be formed by annealing (RTA-II) the ion implanted epi-silicide. When the temperature of RTA-I is as low as possible and that of RTA-II is moderate, the p$^{+}$n junction that has low leakage current and stable epi-silicide layer could be obtained. That is, when th econdition of TRA-I was 900$^{\circ}C$/20sec and that of RTA-II was 900$^{\circ}C$/10sec, the reverse leakage current was as high as 11.3$\mu$A/cm$^{2}$ at -5V. The surface of CoSi$_{2}$ appeared considerably rough. However, when the conditon of RTA-I was 800$^{\circ}C$/20sec or 700$^{\circ}C$/20sec, the leakage currents were as low as 8.3nA/cm$^{2}$ and 9.3nA/cm$^{2}$, respectively and also the surfaces appeared very uniform.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.30-33
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• 2004

Shallow p+-n junctions were formed by low-energy 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. A new simulator is designed to model boron diffusion in silicon, which is especially useful for analyzing the annealing process subsequent to ion implantation. 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 a resonable parameter values, the simulator covers not only the equilibrium diffusion conditions but also the nonequilibrium post-implantation diffusion. Using initial conditions and boundary conditions, coupled diffusion equation is solved successfully. The simulator reproduced experimental data successfully.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.349-352
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• 2001

In this paper, novel device structure 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) for ultra pn junction formation. 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 10~20 nm for arsenic dosage (2$\times$10$^{14}$ $\textrm{cm}^2$), excimer laser source(λ=248nm) is KrF, and sheet resistances are measured to 1k$\Omega$/$\square$ at junction depth of 15nm.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.4
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• pp.190-194
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• 2000

Dispersion coefficient influenced by the wave parameters was derived analytically using the vertical velocity distribution based on linear wave theory. It is the depth- and wave period-averaged value and shows larger values in deep water condition than in shallow water condition. It also shows the general pattern of the dispersion coefficient in the oscillatory flows, i.e. it converges the specific value as the wave period is much larger than the vertical mixing time but it approaches zcro as the wave period is much smaller than the vertical mixing time. The dispersion coefficient derived in the condition of the simple assumption have to be modified in order to consider the shallow water condition or the real condition.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.495-501
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• 2009

The study was conducted in 2007~2008 in order to understand preference of physical microhabitat on the $1^{st}$-class endangered species, Gobiobotia naktongensis inhabiting the Gam Stream, tributary of Nakdong River. The total number of fish caught from the study sites was 3,671 representing 7 families 24 species. There were 8 Korean endemic species including Odontobutis platycephala, and 2 introduced species (Carassius cuvieri, Micropterus salmoides) were found. According to investigation and analysis of physical microhabitat on Gobiobotia naktongensis caught in the Gam Stream, a total of 57 individuals were found at shallow depth (0.14~0.46 m) and run (0.239~0.585m $sec^{-1}$). As a result of sieve analysis, stream beds consisted of about 1% gravel and 99% sand (83.4% coarse sand, 15.6% find sand). Therefore, Gobiobotia naktongensis seemed to inhabit shallow-run with coarse sand bed than deep-pool microhabitat. The findings indicate preference of physical microhabitat on Gobiobotia naktongensis, and it is important to enhance efficiency of fish conservation and ecological restoration with understanding species-specific characteristics in microhabitat including protected species.

• The Journal of the Acoustical Society of Korea
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• v.17 no.1E
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• pp.54-65
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• 1998

This study attempts to test the classifying performance of a neural network and thereby examine its applicability to the signals distorted in a shallow water environment. Linear frequency modulated(LFM) signals are simulated by using an acoustic model and also measured through sea experiment. The network is constructed to have three layers and trained on both data sets. To get normalized power spectra as feature vectors, the study considers the three transforms : shot-time Fourier transform (STFT), wavelet transform (WT) and pseudo Wigner-Ville distribution (PWVD). After trained on the simulated signals over water depth, the network gives over 95% performance with the signal to noise ratio (SNR) being up to-10 dB. Among the transforms, the PWVD presents the best performance particularly in a highly noisy condition. The network performs worse with the summer sound speed profile than with the winter profile. It is also expected to present much different performance by the variation of bottom property. When the network is trained on the measured signals, it gives a little better results than that trained on the simulated data. In conclusion, the simulated signals are successfully applied to training a network, and the trained network performs well in classifying the signals distorted by a surrounding environment and corrupted by noise.

• Ocean and Polar Research
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• v.42 no.1
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• pp.1-13
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• 2020

We analyzed the characteristics of meiofaunal communities in the northern part of Jeju Island and the environmental factors affecting the meiofaunal communities. For the analysis of the communities, subtidal sediments containing meiofauna were collected from 6 sites (3 shallow sites and 3 deeper sites) on the northern coast of Jeju Island in April, June, August, and October 2017. The sediment samples were collected by SCUBA using a syringe. After isolating and counting meiofauna from the sediment using a series of sieves and centrifugation, the density of the meiofauna was expressed as individuals/10 ㎠. Density of meiofauna was lower in August compared to April and June, and the density determined in October was higher than August. During April and June, the meiofaunal communities at the shallow sites (i.e., ST 1, 2, and 3) were significantly different from the meiofaunal communities at deeper sites (ST 4, 5, and 6, p < 0.01). However, such spatial variation in the meiofaunal communities was not obvious in August and October. The most dominant meiofaunal taxa were harpacticoids, followed by nematodes and nauplius larvae. These three taxa accounted for 90% of the total meiofauna density. Abundance of harpacticoids and nematodes showed a significantly negative correlation with the water depth. BIO-ENV analysis indicated that the total organic nitrogen (TON) and the water temperature exerted a significant influence over the meiofaunal communities at the sampling sites.

• Journal of Korea Water Resources Association
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• v.44 no.6
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• pp.461-470
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• 2011

Abrupt and gradual levee breach analyses on the flat domain were implemented by laboratory experiments and numerical simulations. To avoid the reflective wave from the side wall the experiment was performed in a large domain surrounded by waterway. A numerical model was developed for solving the two-dimensional gradual levee breach flow. The results of the numerical simulation developed in this study showed good agreement with those of the experimental data. However, even if the numerical schemes effectively replicated the trends of the observed water depth for the first shock, there were little differences for the second shock. In addition, even though the model considered the Smagorinsky horizontal eddy viscosity, the location and height of the hydraulic jump in the numerical simulation were not fairly well agree with experimental measurements. This shows the shallow water equation solver has a limitation which does not exactly reproduce the energy dissipation from the hydraulic jump. Further study might be required, considering the energy dissipation due to the hydraulic jump or transition flow from reflective wave.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.155-160
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• 2002

In this paper, a compliant buoy mooring system of a floating cylindrical structure in shallow water depth is studied experimentally. The compliant buoy mooring system consists of four buoys, vertical mooring legs and horizontal mooring lines. A series of model test were carried out at KRISO ocean engineering basin for various mooring parameters; line length, pretension of mooring leg and mooring layouts and environmental conditions; regular and irregular waves combined with current and wind. The mooring line tensions and 6-DOF motions of the floating structure were measured using water-proof load cells and 3 CCD camera system. The results of a series of model tests were discussed on nonlinear motion behaviors of the floating structure and characterisitics of cumulative distributions of mooring line peak tensions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.132-138
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• 2003

In order to evaluate properly ship motion relating to the berthing maneuver, the hydrodynamic forces acting on ship hull in berthing maneuver need to be estimated rightly. CFD has been employed for time-domain simulation of transient flow induced by Wigley model moving laterally from rest in shallow water. The numerical solutions successfully captured not only the characteristics of the transitional hydrodynamic forces but also some interesting features of the flow field around a berthing ship according to the water depth. In this paper, the consideration is carried out on the approximate formula based on the CFD results, which can estimate hydrodynamic forces especially lateral drag coefficient starting from the rest to the uniform movement.