• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.73-78
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• 2016

The oxidation states of structural Fe in clay minerals often reflect the paleo-redox conditions of the depositional environments. It is inevitable to utilize the high resolution of transmission electron microscopy (TEM) to investigate the mechanism of mineral transformation at nano-scale. The applications of TEM- electron energy loss spectroscopy (EELS) for quantification of $Fe(III)/{\Sigma}Fe$ from the K-nontronite formation associated with structural Fe(III) reduction in nontronite under deep subseafloor environment were demonstrated. In particular, quantification of the changes in Fe-oxidation state at nanoscale is essential to understand the mechanisms of minerals formation. The procedure of EELS acquisition, quantitative determination of Fe-oxidation states, and advantages of EELS techniques were discussed.

• Journal of the Korean Society of Safety
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• v.20 no.4 s.72
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• pp.40-45
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• 2005

The principal actions of a flame retardant are to decrease or prevent the formation of volatile products and increase the formation of char layer. Use of flame retardant additives can decrease the overall fire hazard of the product containing them thus leading to an increase in overall fire safety. Although several flame retardants have been developed for use in polymers, many of these are known to increase the amount of smoke and toxic gases generated by them. This paper present a new flame retardant using metal addition flame retardant. For this study, the experiments of flame retardancy conducted are as follows : burning ratio, weight loss rate using TGA-DTA, the measurement of LOI and char yield. And smoke mass concentration and CO yield were measured. The metal addition flame retardant reduced burning ratio and weight loss rate, increased the LOI and yield of char formation with decreased smoke mass concentration and CO yield.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1164-1166
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• 2009

Aromatic aldehydes are efficiently self-condensed into $\alpha$-hydroxy carbonyl compounds by polystyrene-supported ammonium cyanide as an excellent organocatalyst in C-C bond formation. The reaction proceeds in water under mild reaction conditions. The polymeric catalyst can be easily separated by filtration and reused several times without appreciable loss of activity.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.5
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• pp.385-389
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• 2013

This paper proposes the leader-follower based formation control method for multiple mobile robots. The controller is designed using the measurements of the follower robot such as the relative distance and angle between the leader and the follower. This means that the follower robot does not require the information of the leader robot while keeping the desired formation. Therefore, the proposed control method can reduce the communication loss and the cost for hardware. From Lyapunov stability theory, it is shown that all error signals in the closed-loop system are uniformly ultimately bounded. Finally, simulation results demonstrate the effectiveness of the proposed control system.

• Journal of KSNVE
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• v.7 no.4
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• pp.631-636
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• 1997

A method to estimate the radiatio power to the surrounding formation due to axial vibration of the pipe in a fluid-filled borehole has been developed, by using the propagation modes of stress wave in an infinitely-long and uniform drilling borehole surrounded by a radially-infinite homogeneous formation. Also, the equivalent damping coefficient for the axial vibration of the pipe has been derived. As an example, results for a real drilling borehole has been presented. The analysis of the elastic motion of the infinite formation which has cylidrical cavity is simplified with the geometric axisymmetry and the low-frequency assumption so that the analytic solution is obtained.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.112-117
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• 2004

The effects of laser heating on soot formation and oxidation of propylene diffusion flames have been studied experimentally under nearly sooting conditions. The non-sooting flame can be converted to a sooting flame when the laser light heats up a flame at 7 mm height, while a sooting flame can be changed to a non-sooting flame when a flame is heated with laser light at flame height of 13 mm. The selective heating at the soot formation and/or oxidation region determines the sooting behavior of a diffusion flame. The increased soot/flame temperatures are most likely to be responsible for both the decreased and increased soot formation/oxidation.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.267-270
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• 2005

We investigate the spectral energy distributions (SEDs) of low mass-loss rate O-rich asymptotic giant branch (AGB) stars using the infrared observational data including the Infrared Space Observatory (ISO) data. Comparing the results of detailed radiative transfer model calculations with observations, we find that the dust formation temperature is much lower than 1000 K for standard dust shell models. We find that the superwind model with a density-enhanced region can be a possible alternative dust shell model for LMOA stars.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.180-185
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• 2017

Restoration of min-impacted arable land is often performed through stabilization of trace elements by amendment treatment combined with (clean) soil covering on the surface. Recently, soil loss problem from sloping remediated agricultural lands has risen as an emerging concern. In this study, efficacy of aggregation formation was assessed by single and binary treatments of four potential amendments (bentonite, lime, organic matter, and steel slag) applied on three cover soils having different clay contents (9.4, 14.7, and 21.2% for A, B, and C soils respectively). In results of single treatments, 5% organic matter for A soil and 5% lime for B and C soils were found most effective for the aggregation formation compared to the respective controls (without amendments). Among nine binary treatments, 3% organic matter + 1% lime for A soil and 1% organic matter + 3% lime for both B and C soils led to the highest formation of aggregation (30.4, 25.0, and 36.5% for A, B, and C soils). For a site-application, the soil erodibility difference between the cover soils (0.045, 0.051, and 0.054 for A, B, and C soils, respectively) and the national average of arable land (0.032) was assumed to be compensated by amendment addition, which is equivalent to 29.1% aggregation formation. To achieve the aggregation goal, 5% lime for A and B soils and 3% lime for C soil were best in the consideration of benefit/cost, thereby effectively and economically reducing soil loss from sloping remediation site. Soil alkalinity induced by lime treatment was not considered in this work.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.429-433
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• 2013

PTFE composites for use of microwave substrate were fabricated by impregnation and heat treatment fabrication with glass fabric. This study shows dielectric properties such as dielectric constant and loss can be controlled by thickness of PTFE composite with change of pressure condition in heating press process. The dielectric constant of the PTFE composites has decreasing tendency as given higher pressure condition. The dielectric loss has similar result too. Especially, the case of the dielectric loss was affected by the condition of pressure at heating press and had the best performance under 3 MPa. In order to see the reason why thickness conditions make different, their microstructures were also observed.

• Journal of Korea Foundry Society
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• v.1 no.3
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• pp.14-18
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• 1981

The Mg-loss of AlSi 7% melts containing from 0 to 0.8% Mg during the Hexachloroethane tablet degassing was investigated. The results of the experiment was discussed in view of the free energy change and kinetics of $MgCl_2$ formation. The melts with Mg content less than 0.5% showed a Mg-loss proportional to Mg-content, while it was constant at about 24% of the weight of tablets, when Mg content of the melt became more than 0.5 %. The rate of Mg-loss was drastically reduced, when the amount of tablets used at a time increased ver a certain limit for a given melt quantity.