• Water Engineering Research
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• v.3 no.3
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• pp.155-162
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• 2002

This study presents the theoretical approach for volume concentration, velocity profile, and granular discharge on the fluid-granule mixed flow downstream of the scour hole at the outlet of the hydraulic structure. Concept of dilatant model was applied for the stress-strain relationships of fluid-granule mixed flow since the flow downstream of the scour hole corresponds to debris flow, where momentum transfers through particle collisions. Mathematical formulations were derived using momentum equation and stress-strain relation of the fluid-granule mixture. Velocity profile under the assumption of uniform concentration over flowing layer showed the downward convex type. Deposition angle of downstream hump was found to be a function of an upstream slope angle, a dynamic friction angle and a volume concentration irrespective of flow itself, Granular discharge and the overflow depth were obtained with given values of inflow rates. Experimental results showed relatively good agreements with theoretical ones.

• Analytical Science and Technology
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• v.8 no.4
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• pp.707-714
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• 1995

Two types of regularization method (singular system and HMP approaches) for generating depth-concentration profiles from angle-resolved XPS data were evaluated. Both approaches showed qualitatively similar results although they employed different numerical algorithms. The application of the regularization method to simulated data demonstrates its excellent utility for the complex depth profile system. It includes the stable restoration of the depth-concentration profiles from the data with considerable random error and the self choice of smoothing parameter that is imperative for the successful application of the regularization method. The self choice of smoothing parameter is based on generalized cross-validation method which lets the data themselves choose the optimal value of the parameter.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.475-478
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• 2005

Deicing salt has been generally used for traffic safety in winter, and the amount is increasing every year. However, deicing salt may induce the decrease of bond strength, surface scaling, and environmental pollution, etc. the purpose of this paper is to suggest the fundamental data on safety and durability for concrete structures through the estimation of chloride concentration profile and chloride diffusion coefficient. According to the test results, the critical chloride concentration($0.9\~1.2kg/m^3$)was measured at depth $23\~30mm$, and the limit chloride concentration($0.3kg/m^3$)was reached to depth 40mm. Also the surface chloride amount indicates 3.45kg per concrete unit weight, and the results showed the possibility of corrosion by deicing salt penetration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.193-199
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• 2000

As an energetic focused-ion beam(FIB) is irradiated on an inorganic amorphous thin film a majority of ions without a reflection at surface, is randomly collided with constituent atoms in thin film. but their distribution exhibits generally a systematic form of distribution. In our previous paper we reported the concentration distribution and the transmission per unit depth of Ga$^{+}$ ions penetrated int a-Se$_{75}$ /Ge$_{25}$ thin film using the LSS-based calculation. In this paper these simulated results are compared with those obtained by a conventional profile code(ISC) and a practical SIMS profile. Then the results of LSS-based calculation have only a small difference with those of code and SIMS Especially. in the case of Ga$^{+}$-FIB with an accelerating energy of 15keV. the depth of the maximum ion concentration is coincident with each other in an error range of $\pm$5$\AA$.EX>.

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.70-73
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• 2003

Nitrate contamination in the aquatic systems is the primary indicator of poor agricultural management. The influence of sewage sludge application rates (0, 10, 25, 50 and 100 dry Mg/ha) on distribution of nitrate originating from the sewage sludge in soil profiles was investigated. Soil profile monitoring of nitrate was carried out with a Lakeland clay soil in 1997. Irrespectively of the sewage sludge application rates up to 50 dry Mg/ha, the concentration of $NO_3$-N at the 120 cm depth was below 10 mg/kg and the difference due to the amount of sewage sludge application was negligible at this depth. There was virtually no $NO_3$-N below 120 cm depth and this was confirmed by a deep sampling up to 300 cm depth. Most of the nitrate remained in the surface 60 cm of the soil. Below 120 cm depth nitrate concentration was very low because of the denitrification even at high sewage sludge rate of 100 dry Mg/ha. The $NO_3$-N concentrations in the soil fluctuated over the growing season due to plant uptake and denitrification. The risk of groundwater contamination by nitrate from sewage sludge application up to high rate of 100 dry Mg/ha was very low in a wheat grown clay soil with high water table ( < 3 m).

• Economic and Environmental Geology
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• v.30 no.5
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• pp.443-450
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• 1997

The main purpose of this study is to investigate mineralogical and chemical changes during natural weathering, and assess the mobility of major and trace elements. Yongwol power plant utilize anthracite coal which is mainly composed of illite, kaolinite, pyrophyllite and quartz in mineralogy. Coal and coal-derived fly ash samples were sampled by the electrostatic precipitator in Yongwol coal-fired power plant in Korea. Short term weathered fly ash were also collected in ash disposal mound, and two profile soil samples were taken from an ash near the power plant. Amorphous materials are the main component of the fly ash, and mullite, quartz, magnetite and heamatite are present in all coal-derived fly ash. In chemistry, Si and Al are the most abundant elements of the total content. The ash samples were fractionated into upper $90{\mu}m$ and under $45{\mu}m$ size. Finer particles show higher concentrations in metal contents including Co, Cr, Cu, Ni, V, Zn and Pb. Concentration of Zn and Pb are nearly 4 times higher concentration in the finer particles. For the profile samples, the concentrations of $SiO_2$, $Na_2O$, MgO and $K_2O$ generally show increasing trends with depth, whereas those of $Fe_2O_3$ and $TiO_2$ appear to decrease with depth. Content of MnO does not show any specific depth trend. For the trace elements, Co, Cu, Ni and V show increasing concentrations with depth.

• Journal of the Korean Vacuum Society
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• v.12 no.3
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• pp.162-167
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• 2003

To find the concentration according to the depth-direction of ions implanted in the sample, with sputtering of the sample surface, one needs the depth profiling of ion implanted in the sample. On measuring of depth profiling, the sputtering rate to affect depth direction, is calculated by SRIM simulation. When ion is implanted in the sample, the atomic density of the sample rises up a little, and it alters sputtering yield. This alteration then causes differences of sputtering rate to affect depth-direction, on measuring of depth profiling. With the usage of SRIM Monte Carlo simulation code, one calculates sputtering rate, with sputtering yield by the alteration of atomic density of the sample through ion implantation. As a result, it goes to prove that its difference affects depth distribution, on measuring of depth profiling.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.3
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• pp.237-241
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• 1999

It was investigated that the condition of fishing ground gave what kind of effect school type in relation to the property for the target school after the vertical temperature profile and school type were observed when tuna purse seiner for tuna purse seine was operated in the western pacific Ocean around the equator between December 12, 1993 and January 26, 1994. The results are as follows;1. This study divided fish schools associated with drift objects, a one targeted-operation, and the pelagic migrating fish schools that are another one for the property. The total of 23 operations were complected including 6 that targeted fish schools associated with drift objects and 17 that targeted pelagic migrating fish schools. It was known that the main operation was conducted on pelagic migrating fish school.2. Average and standard deviation of the depth of the surface mixing layer was 86.0m and 13.8m for fish schools associated with drift objects. 61.6m and 13.0m for pelagic migrating fish schools, respectively. The average depth of the surface mixing layer of the pelagic migrating fish schools was lower when compared to the fish schools associated with drift objects however the concentration of standard deviation was higher than those fish schools associated with drifted objects. Accordingly, it was assumed that the effect of vertical temperature profile for pelagic migrating fish school was higher than the fish schools associated with drift objects.

• Journal of the Korean institute of surface engineering
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• v.35 no.6
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• pp.383-390
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• 2002

To investigate behaviors of Ti and O elements and microstructures of anodic titanium oxide films, the films were prepared by anodizing pure titanium in $H_2$S $O_4$, $H_3$P $O_4$, and $H_2O$$_2$ mixed solution at 180V. The microstructures and chemical states of the elements were analyzed using SEM, X-ray mapping, AFM, XRD, XPS (depth profile). The films formed on a titanium substrate showed porous layers which were composed of pore and wall, And with increasing anodizing time a hexagonal shape of cell structures were dominant and solace roughness increased. From the XRD result the structure of the Ti $O_2$ layer was anatase type of crystal on the whole. In the XPS spectra it was found that Ti and O were chemically binded in forms of Ti $O_2$, TiOH, $Ti_2$ $O_3$ at Ti 2p, and Ti $O_2$, $Ti_2$ $O_3$, $P_2$ $O_{5}$, S $O_4^{2-}$ at O ls respectively. Concentration of Ti $O_2$ decreased as the depth increased from the surface of the oxide film towards the substrate, but to the contrary concentrations of TiOH and $Ti_2$ $O_3$ increased.d.

• Asian Journal of Turfgrass Science
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• v.7 no.2_3
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• pp.55-60
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• 1993

Soil profile was well developed into four horizons, $A_1$, $A_3$, $B_2$and C at 100cm-depth in most four golf courses in Kyonggi province. Distribution of root system of Korean lawngrass was abundant in dark yellowish or yellowish brown $A_1$ horizon with low hardness(8~14mm yamanaka scale), moderately in yellowish brown $A_3$ horizon with moderate hardness(16~23mm) rarely in $B_3$horizon(15~60cm depth) and no in C horizon. Optimum soil hardness for good root growth of Korean lawngrass appeared to be less than 16mm mineral nutrient contents. Such as Ca++, Mg++, K+, Mn++ and Fe showed relatively higher concentration in lower horizon indicating the leaching of minerals. The increasing tendency of soil pH with depth seemed to the result of mineral leaching. There was significant positive correlation between Ca+Mg and pH, manganese content appeared to be too high(261~789ppm) in $A_1$ horizon. The contents of organic matter and phosphorus were bight in $A_1$ horizon and greatly varied among golf courses.