• Journal of Korea Foresty Energy
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• v.21 no.3
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• pp.34-45
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• 2002

This study was carried out to investigate the diversity and frequency of ectomycorrhizal fungi by cutting levels in Quercus acuta and Pinus densiflora stands from June to October, 2001. The obtained results from investigation were as follows, 1. The total of fungi found during the surveyed periods were 50 species, 30 genus, 15 families. The fungi belonged to Agaricales(37 species, 18 genus, 7 families), Aphllophorales(7 species, 6 genus, 3 families), Auriculariales(1 species, 1 genus, 1 families) and Gasteromycetes(5 species, 5 genus, 4 families), Basidiomycota. 2. The total number of putative ectomycorrhizal fruiting bodies were 137 individuals, 22 species, 10 genus, 5 families, 79 individuals, 10 species, 6 genus, 3 families at strip-cutting area of Pinus densiflora stand, 24 individuals, 9 species, 5 genus, 4 families at strip-cutting area of Quercus acuta stand and 25 individuals, 10 species, 4 genus, 3 families at spacing cutting area of Quercus acuta stand. 3. Tylropilus neofelleus had high host specificity associated with Chamaecyparis obtusa, while Amanita pseudoporphyria had relatively wide host ranges compared to other ectomycorrhizal fungi. 4. The results analyzed by Correlation coefficients showed that relative humidity and precipitation were major enviromental factors to affect the distribution of ectomycorrhizal fruiting bodies.

• Economic and Environmental Geology
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• v.24 no.3
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• pp.319-327
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• 1991

Cheju is the biggest island in Korean peninsula, consisted entirely of volcanic rocks and pyroclastic sediments. The topography is characterized by wide basalt plain in the low altitude but at the center of island, basalt volcano rises 1,950m above sea-level. Surface drainage is very poor, therefore water supply has been dependent on ground water and natural springs. There are about 1,650 production wells and most of them yield $1,000{\sim}2,000mm^3/day$. According to increase of ground water use, saline water is intruded in the low altitude of coastal area. Specially in the eastern coastal area, the topography is extensively flat and the level of ground water is very close to sea-level, at which overuse of ground water has brought saline intrusion up to maximum 6km far from the coast. Hydrochemical monitoring on this salt water intrusion is now undertaken on long term base.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.253-262
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• 2014

This study was conducted to find methods of qualitative landscape assessment for vegetational landscapes using ecological analysis. The study site was Seoraksan National Park in Korea. For this study, differing unique landscape resources were categorized and identified according to ecosystems. After identifying the study areas, the relationship between trail visitor preference and the amount of visible overexposure caused by people to the resources was examined. Landscape resources chosen for ecological analysis at Seoraksan National Park were subalpine vegetation community, high mountain rocks, ombrogenous deciduous broadleaf forest in the valley area, edaphic climax community, big tree community, flowering tree dominant community, autumnal tree dominant community and needle-leaf forest in the subalpine area. As a result of the study, it was found that the landscape resources with the highest correlation to visitor trail preference were big tree community area, flowering tree dominant community area, and needle-leaf forest in the subalpine area. As a result of overlapping the analysis of the amount of visible overexposure to the landscape resources and the analysis of preferential use of trails by visitors, guidance for the appropriate season for each trail can be provided. Since a positive correlation exists between certain sections of the natural landscapes and visitor preference, ecological impact on landscape resource ecosystems did not appear to cover wide areas of the trails, but was limited to certain areas preferred by visitors.

• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.93-98
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• 2018

In this paper, an energy-efficient 11.49-bit successive approximation register (SAR) capacitance-to-digital converter (CDC) for capacitive sensors with a figure of merit (FoM) of 31.6 pJ/conversion-step is presented. The CDC employs a SAR algorithm to obtain low power consumption and a simplified structure. The proposed circuit uses a capacitive sensing amplifier (CSA) and a dynamic latch comparator to achieve parasitic capacitance-insensitive operation. The CSA adopts a correlated double sampling (CDS) technique to reduce flicker (1/f) noise to achieve low-noise characteristics. The SAR algorithm is implemented in dual operating mode, using an 8-bit coarse programmable capacitor array in the capacitance-domain and an 8-bit R-2R digital-to-analog converter (DAC) in the charge-domain. The proposed CDC achieves a wide input capacitance range of 29.4 pF and a high resolution of 0.449 fF. The CDC is fabricated in a $0.18-{\mu}m$ 1P6M complementary metal-oxide-semiconductor (CMOS) process with an active area of 0.55 mm2. The total power consumption of the CDC is $86.4{\mu}W$ with a 1.8-V supply. The SAR CDC achieves a measured 11.49-bit resolution within a conversion time of 1.025 ms and an energy-efficiency FoM of 31.6 pJ/step.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.199-206
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• 2004

Construction of a large offshore structure in coastal area may cause serious morphological changes for a wide region ranging from shoreline to offshore behind the structure. Shin et at. [2000] and Shin and Hong [2004] identified the sediment transport patterns behind the large offshore structure through a series of three dimensional movable bed experiments. In present study, a hybrid three dimensional beach deformation model was suggested based on those sediment transport mechanisms revealed by experimental results of the preceding studies. The model was verified by the results of the three dimensional moveable bed experiments and they agreed well not only in reappeared tombolo in shoreline side but also in the erosion and deposition region behind offshore structure. In addition, the model was applied to real beach deformation problem, which was occurred by construction of artificial offshore islands, and it validates the applicability of the model.

• Clean Technology
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• v.18 no.1
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• pp.14-21
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• 2012

The pros and cons of green building thermal insulation materials and systems have been reviewed from traditional thermal insulation materials such as mineral wool and polyurethane to new thermal insulation materials like VIP and aerogel and future insulating VIM and DIM. VIPs and aerogels with very low thermal conductivity can use for green buildings to significantly increase residential area by reducing energy consumption. Aerogels can be produced as not only opaque and but also translucent forms, thus enabling a wide range of possible building application. For building applications, there are many properties to consider like building site adaptability and mechanical strength, fire protection, cost and environmental impact.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.57-61
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• 2008

In order to maintain the continual safety management in a company, it needs to evaluate and monitor its implementation of safety management. Because the number of major-accidents is not an effective method of indicating company's safety performance, various efforts to develop more reasonable indicators have been made in world wide. After Korean government has legally required the PSM report, PSM compliance audit has been developed and made by the authorities concerned since 2005. However, this audit consists of complicate procedures difficult to utilize as companies' own audit program and corresponds to only a conformity check that confirms whether the PSM be operated and maintained properly. So a new index by which to measure easily the level of safety performance and self-monitor the implementation of safety management is needed. We have studied a new method that may quantitatively evaluate the performance of safety management by investigating application cases in foreign countries and doing the domestic survey of lots of companies subject to PSM regulation in Korea. This study proposes three of safety performance indices(SPI) together with the several prerequisite preconditions and the timing for application of each index. Although the first draft of SPI needs further legal support, it might help to evaluate every company's safety level. The second draft of SPI is a voluntarily evaluating method based on web-site online program. The last draft of SPI consists of a series of simple questions about 12 elements of PSM. Also each of 3 indices has differences in evaluation methodology and application area and, therefore, they may be used concurrently.

• Membrane Journal
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• v.31 no.4
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• pp.241-252
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• 2021

Rapid industrialization with growing population leads to environmental water pollution. Demand in generation of clean water from waste water is ever increasing by scarcity of rain water due to change in weather pattern. Colorimetric detection of heavy metal present in clean water is very simple and effective technique. In this review membrane based colorimetric detection of mercury (II) ions are discussed in details. Membrane such as cellulose, polycaprolactone, chitosan, polysulfone etc., are used as support for metal ion detection. Nanofiber based materials have wide range of applications in energy, environment and biomedical research. Membranes made up of nanofiber consist up plenty of functional groups available in the polymer along with large surface area and high porosity. As a result, it is easy for surface modification and grafting of ligand on the fiber surface enhanced nanoparticles attachment.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.491-496
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• 2023

As the demand for p-type semiconductors increases, much effort is being put into developing new p-type materials. This demand has led to the development of novel new p-type semiconductors that go beyond existing p-type semiconductors. Copper iodide (CuI) has recently received much attention due to its wide band gap, excellent optical and electrical properties, and low temperature synthesis. However, there are limits to its use as a semiconductor material for thin film transistor devices due to the uncontrolled generation of copper vacancies and excessive hole doping. In this work, p-type CuI semiconductors were fabricated using the chemical vapor deposition (CVD) process for thin-film transistor (TFT) applications. The vacuum process has advantages over conventional solution processes, including conformal coating, large area uniformity, easy thickness control and so on. CuI thin films were fabricated at various deposition temperatures from 150 to 250 ℃ The surface roughness root mean square (RMS) value, which is related to carrier transport, decreases with increasing deposition temperature. Hall effect measurements showed that all fabricated CuI films had p-type behavior and that the Hall mobility decreased with increasing deposition temperature. The CuI TFTs showed no clear on/off because of the high concentration of carriers. By adopting a Zn capping layer, carrier concentrations decreased, leading to clear on and off behavior. Finally, stability tests of the PBS and NBS showed a threshold voltage shift within ±1 V.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.22-24
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• 2007

Waterline extraction is the one of widely used methods for studying changes in tidal flat environment and coastlines using multi-temporal optical images such as Landsat TM and Landsat ETM+. High dynamics of tidal currents and land reclamation which accelerate sedimentation and/or erosion cause waterline change in tidal flats. The amount of sediment deposited or eroded can be evaluated by precisely estimating waterline changes in tidal flats. The objective of this study is to detect the change of waterlines during 17 years and analyze the trends of erosion and sedimentation in the study areas. The Ganghwado tidal flat on the west coast of the Korean Peninsula was selected. The study area is famous for high dynamics of tidal currents and vast tidal flats. Land reclamation which has been carried out on a large scale is also considered as one of elements that have accelerated the environmental changes in this tidal flat. In this study, we acquired 26 waterlines from Landsat TM and Landsat ETM+ images. We extracted the waterline from each satellite image to generate a digital elevation map (DEM) which was used for reference and to compare with the other waterline which was extracted from DEM having a same tide. The result of comparison well depicted the areas of dominant sedimentation and erosion, and general trends of sedimentation and erosion according to sub-regions are also revealed during the investigation time. Results showed that erosion during a decade was dominant at the west of the Southern Ganghwado tidal flat, while sedimentation was dominant at the wide channel between the Southern Ganghwado tidal flat and the Yeongjongdo tidal flat. This area has been commonly affected by high currents and sedimentation energy. Although we were not able to verify the accuracy of the waterline changes, this result clearly showed the waterline change and therefore, the waterline extraction method used in this study has proven as an effective tool for long term tidal change estimation.