• Analytical Science and Technology
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• v.16 no.2
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• pp.174-178
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• 2003

Analytical chemists frequently use filter papers during the course of experiments without any hesitation. However, the results of analysis could be deteriorated by the various ions which are extracted from filter papers. In some filter paper made for qualitative use, about $300{\mu}g$ sodium and many other cations were detected. Although the quantities of contaminants was low in the filter paper made for quantitative use, significant amount of Fe, Si, Al, Cu and Zn was detected as well as alkali element. Many cations and anions were also detected in the filtrate obtained from the glass fiber filter.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.3
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• pp.60-71
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• 1989

In this paper the structure of an engine and its interaction are investigated by a mathematical model for the performance evaluation. The total system is composed of air-fuel inlet element, intake manifold, combustion, engine dynamics and emission. Their control functions are schematically evaluated. Because of the model constructure with general engine functions and computer simulation of the chosen engine, physical characteristics of the corresponding engine and the engine data of normal operation states are used. According to the study, it is possible to predict the mixture rate by the difference in the mass of fuel and air flowing into cylinder and to evaluate and trace dynamic characteristic of operation state under various operating conditions. The model characteristic under the transient operating condition to evaluate operating of actual engine through the result of simulation.

• Journal of Nutrition and Health
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• v.4 no.3
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• pp.1-4
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• 1971

Zinc is an essential trace element. Previos methods for the determination of zinc in serum have been difficult and reported findings must be treated with caution. The normal range of zinc in serum varies significantly according to different methods and author. The scope of this work was to establish the normal range of zinc in serum values in healthy Korean persons. Methods are described for the determination of zinc in serum diluted ten-fold with deionised water using Hitachi Model 207, atomic absorption spectrophotometer. The values of zinc in serum of 23 healthy Korean persons by atomic absorption spectroscopy ranged from 87.6 to $131.2\;{\mu}g/100\;ml$ with the mean value $109.1\;{\mu}g/100\;ml$ and standard deviation 10.86. In this method, satifactory result was obtained with regard to the coefficient variation and recoveries of added zinc in the measurenents.

• Journal of Astronomy and Space Sciences
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• v.20 no.3
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• pp.227-238
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• 2003

Spacecraft mission planning functions including event prediction, mission scheduling, command planning, and ground track display have been developed for the KOMPSAT-2 mission operations. Integrated event prediction functions including satellite orbital events, user requested imaging events, and satellite operational events have been implemented. Mission scheduling functions have been realized to detect the mission conflicts considering the user specified constraints and resources, A conflict free mission scheduling result is mapped into the spacecraft command sequences in the command planning functions. The command sequences are directly linked to the spacecraft operations using eXtensible Markup Language(XML) for command transmission. Ground track display shows the satellite ground trace and mission activities on a digitized world map with zoom capability.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.752-756
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• 2002

Variable weld bead penetrations related to the base metal chemistry of stainless steels in GTA welding have been under constant investigations due to their industrial implications. It has been proposed that among other elements, the sulfur content of steels determines the weld pool geometry, particularly its penetration. It is suggested that the surface tension temperature gradient of steels becomes positive with appropriate dosing in sulfur and results in inward melt flow, propitious for deeper welds. However, the chemistry of industrial steels is complex due to the presence of multiple minor elements either deliberately added or remnant impurity traces. With this in view, investigations on 41 austenitic and nine martensitic stainless steels were carried to see if there existed any possible relation between the weld profile and some of the designated elements. The results suggest no direct correlation between sulfur or any other major or trace element and weld penetration. At first glance the results are contradictory to what is often asserted.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.77.2-77.2
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• 2014

Questions of how our Milky Way evolves through the interaction with its environment have been constantly raised. One particularly interesting question is how the metallicity would change as our Milky Way goes through collision with HVCs. Because of the possibility of HVCs providing fuel for star formation in the Galactic disk, we simulate the collision between HVCs and the Galactic disk. More specifically, we trace how the Galactic metallicity changes throughout the process of HVCs colliding with our Milky Way based upon a specific scenario that HVCs are primordial gas left-overs from an ancient galaxy formation. Such mixing between metal-rich gas (disk) and metal-poor HVC can be traced by running numerical simulations with the FLASH code due to its capability of tracking down the abundance change of a specific element such as carbon at each time step of the hydrodynamic evolution. As for now, we give how this mixing depends on model parameters that we choose such as collision speed, initial metallicities, temperature and so on.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.812-816
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• 2016

We isolated a novel methylotrophic bacterium from soil collected in Dongducheon Environment Affairs Agency. The isolate was identified as Methylobacterium sp. WJ4 based on phylogenetic analysis. Plackett-Burman design was employed for screening eight parameters of nitrate mineral salts (NMS) medium for cell growth of a newly isolated Methylobacterium sp. WJ4 with experimental validation. Trace element solution and vitamin stock were found to affect cell growth, which can be further optimized for increased cell growth. This is the first report of screening parameters of NMS medium which affect cell growth of strain belonging to the genus Methylobacterium using Plackett-Burman design.

• Journal of Ocean Engineering and Technology
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• v.9 no.1
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• pp.22-35
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• 1995

A simplified numerical procedure have proposed to trace the dynamic behaviour of offshore tubulars subjected to lateral collision impacts. The local denting and overall bending deformation of the struck tubular are represented by a non-linear spring and an elastic visco-plastic beam respectively. In this method a temporal finite difference method and a spacial finite element method are employed. Using this method various boundary conditions are able to considered and their effects on the extent of damage can be quantified. The extent of damage due to collision can be obtained as results of the dynamic analysis. The predictions using the proposed method have been correlated with existing test results and then the reliability of the procedure has been substantiated. The characteristics of the dynamic response of tubulars under lateral impacts are compared for simply supported roller and fixed end conditions and their effects on the extent of damage are specfied.

• The Journal of the Petrological Society of Korea
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• v.2 no.1
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• pp.41-52
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• 1993

We report adventages of employing MgO as a differentiation index for the Namwon granitic complex. It is shown to be much more sensitive than the usual Harker index. The complex can be divided into two groups on the basis of $TiO_2$/MgO ratio. The low $TiO_2$/MgO group consists of hornblende biotite tonalite-granodiorite, porphyritic hornblende biotite granodiorite (PHBGd) and part of biotite granite (loBG). PHBGd shows its own distinct variation in the low group. This group is characterized in most cases by the presence of hornblende, even if it occurs as a trace amount. The high $TiO_2$/MgO group consists of part of biotite granite (hiBG) and two mica granite. The major element differences between rock types are also apparent in biotite chemistry. These chemical data indicate that at least two distinct origins of magma are rquired for the complex. Two kinds of biotite granite revealed in this study show distinct geographic distribution, suggesting that a new geologic map should be made.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.295-298
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• 2004

It was revealed that leaching of elements were partly inhibited because seawater contains plenty of dissolved ions than fresh water. On the other hands, the low activity coefficient and the formation of complex with chloride and sulfate play roles in enhancing element leachability. However, the pH buffaring capacity of seawater is the most important factor that makes the leaching of elements and its chemical behavior in the seawater system different from those in the fresh water environments. In general, the leaching from the weathered ash was smaller than that from the fresh ash. However, it was revealed that the leaching of Si, Fe, Al, Mn, phosphate, and some other elements were independent of ash weathering. They were dependant only on the pH of the solutions.