• Ceramist
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• v.10 no.3
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• pp.75-85
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• 2007

Over the past few years, due to the great development of optical communications, an increasing R&D activity has been focused on the design and manufacture of the integrated optic amplifiers, with particular reference to their application in wavelength-division-multiplexing (WDM) systems. In this technological context, rare-earth-doped oxide glasses, which had been widely used for solid state lasers, gained much attention as highly performing materials in the third telecom window, around 1.5 micron. The aim of the present paper is to provide a brief overview of the progress made, with particular reference to the authors' work in this area, and to shortly discuss its perspectives.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.81-84
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• 1977

This study was conducted to develop the leveller suitable for power tiller which has been widely used in Korea. Field test was carried out to determine its performance in accordance with the tilt angles of blede, forward velocities , and the length of blade . The results are follows ; 1. Earth moving capacity of the standard leveller was found to be 90~95kg of soil per one swath while working at the 2nd ~4th gears of forward speed. 2. Work performance of model leveller was 2 , 3, 4 times higher than manual operation in distributing additional soil of thickness 6mm , 12 mm and 24 mm on paddyland, respectively. 3. Levelling performance of model leveller on the inclined fields was 7 ~9 times higher than manual operation.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.613-616
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• 2008

Assessment of geothermal resources like other earth resources is a starting point for decision makers or stakeholders to set up basic plan on its development and R&D policies. In this context, there have been various works on world geothermal assessment, to report different estimates from each other. In this paper, we first introduce the definition of geothermal potential mainly adopted from the article by Muffler and Cataldi (1978) and then summarize the estimates made so far referring the work by Bertani (2003). An updated estimates by Stefansson (2005) are also reviewed in terms of identified resources separately for high-temperature resources for power generation and low-temperature ones for direct-use. Recent estimate of US geothermal resources by MIT (2006) using a volumetric method with extensively accumulated data base is discussed. Finally, we introduce the first geothermal assessment in Korea recently made and discuss its importance.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1576-1580
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• 2006

The destruction of river and damage caused by flood are suddenly increasing due to the abnormal climate. In the investigation result about the damage, approximate 52% of the destruction of embankment are caused by earth work. Moreover, to recover conveyance of relief channel, bed sediment is dredged about 198 millions $m^3$ with 'the project of bed dredging'. So, the concern for bed sediment is the more increasing, the requiring high quality material for banking and the way for application of bed sediment are also the more increasing. In this paper, properties of bed sediment were analyzed through sedimentary mechanism analysis. Moreover, possibility to build embankment with bed sediment in 6 points which is in catchment of the Nak-dong river was also analyzed. At 6 points, which were selected to survey easily, sediment discharge was analyzed with formula. Moreover, size and permeability were analyzed and the feasibility for material of embankment was proposed. If bed sediment wasn't proper, complementary measures were proposed.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.122-127
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• 1998

Conductivities of polycrystalline ceria doped with several rare earth oxides were measured by AC admittance and DC four probe method. The conductions were separated into grain and grain boundary contributions using the complex admittance technique as well as grain size dependence of conductivity. The grain size dependence of polycrystalline conductivity, which can be adequately described by the so-called brick layer model, appears to give a more reliable measure of the grain conductivity compared to the complex admittance method. Polycrystalline resistivity(1/conductivity) increases linearly with the reciprocal of grain size. The intercept of resistivity vs. inverse grain size plot gives a measure of the grain resistivity and the slope gives a measure of the grain boundary resistivity. It was also noted that errors involved in the analysis of experimental data may be different between the complex admittance method and the impedance method. A greater resolution of the spectra was found in the complex admittance method, insofar as the present work is concerned, suggesting that the commonly used equivalent circuit may require re-evaluation.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.2
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• pp.269-274
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• 2005

In this work, analytical bias arising from the gas chromatographic determination of sulfur compounds was evaluated by the application of direct loop injection method to the GC/PFPD detection of four sulfur compounds including H$_{2}$S, CH$_{3}$SH, DMS, and DMDS. For the proper evaluation of analytical uncertainties involved in GC calibration, we employed two comparative techniques of calibration at fxed concentration injection (CFCI) vs calibration at fixed volume injection (CFVI) method. The results of our study indicate that CFCI method exhibits very poor sensitivity due to the matrix effect with varying injection volumes. On the other hand, as CFVI method overcomes such limitation, it can be used to obtain very accurate quantification of S compounds at their high concentration levels above a few to a few tens ppb.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.165-167
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• 2006

On our return to India from Germany, we have worked on the development of parabolic solar concentrators with input and collaboration of German and Austrian inventors. We have gradually improved the solar technologies to include food processing based on inputs and feedback from users to fulfill their specific requirements. We will discuss the acceptability and commercialisation of various systems that we have successfully developed, their implications and their benefit. These success stories can work as multipliers. These concentrators can have various other applications. The Global Treaty Kyoto Protocol's CDM (Clean Development Mechanism) can result in a win-win situation for both developing and developed nations and the world environment at large - whereby developed nations get carbon credits by supporting renewable energy projects in developing nations. North-South dialogue and South-South dialogue can effectively foster global co-operation meaningfully to benefit People and environments ensuring sustainable development and protection of Our planet Earth, our only HOME!!!

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.21-31
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• 2018

The result of examination of diagnostic method, which is composed of a combination of a thermal camera and a drone that visually shows the temperature of the object by detecting the infrared rays, for detecting the leakage of earth dam was driven in this research. The drone infrared thermography method was suggested to precise safety diagnosis through direct comparing the two method results of electrical resistivity survey and thermal image survey. The important advantage of the thermal leakage detection method was the simplicity of the application, the quickness of the results, and the effectiveness of the work in combination with the existing diagnosis method.

• CELLMED
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• v.5 no.4
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• pp.24.1-24.7
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• 2015

Bahunia racemosa family, Caesalpiniaceae, is one of the precious resources of the earth. It has played a significant role in human civilization since ancient times. It is tall sized tree growing throughout India, Ceylon, China, and Timor. The different part of this plant contains β-sitosterol and β-amyrin, flavonols (kaempferol and quercetin) and two coumarins (scopoletin and scopolin), tannins etc. Various part of this plant has great pharmacological potential with a great utility and usage as folklore medicine as analgesic, antipyretic, anti-inflammatory, antispasmodic and antimicrobial activity. This review mainly focus on the exclusive review work on the traditional, phytochemical and pharmacological activities of this plant.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.147-155
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• 1999

In this work variations of orbital parameters are derived from the perturbation equations under Earth oblateness and atmospheric drag. A simple and effective scheme is proposed to compute the required delta v and fuel consumption to compensate for atmospheric drag. The scheme is applied to KOMPSAT example.