• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1349-1355
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• 2014

A three-dimensional (3D) $Co_3O_4$/mildly oxidized multiwalled carbon nanotubes (moCNTs)/reduced mildly oxidized graphene oxide (rmGO) ternary composite was prepared via a simple and green hydrolysishydrothermal approach by mixing $Co(Ac)_2{\cdot}4H_2O$ with moCNTs and mGO suspension in mixed ethanol/$H_2O$. As characterized by scanning electron microscopy and transmission electron microscopy, $Co_3O_4$ nanoparticles with size of 20-100 nm and moCNTs are effectively anchored in mGO. Cyclic voltammetry and galvanostatic charge-discharge measurements were adopted to investigate the electrochemical properties of $Co_3O_4$/moCNTs/rmGO ternary composite in 6 M KOH solution. In a potential window of 0-0.6 V vs. Hg/HgO, the composite delivers an initial specific capacitance of 492 $Fg^{-1}$ at 0.5 $Ag^{-1}$ and the capacitance remains 592 $Fg^{-1}$ after 2000 cycles, while the pure $Co_3O_4$ shows obviously capacitance fading, indicating that rmGO and moCNTs greatly enhance the electrochemical performance of $Co_3O_4$.

• Journal of Forest and Environmental Science
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• v.31 no.1
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• pp.14-23
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• 2015

In this study, we investigated the effects of three land uses on soil properties in two soil layers; surface soil (0~15 cm) and subsoil (15~30 cm). Soil samples were collected from planted forest, barren lands and cultivated lands from different areas in Chittagong Cox's Bazar and analyzed for some physical and chemical properties. Results showed that soil textural class varied from sandy clay loam in planted forest and barren land site to sandy loam in cultivated soils. Maximum water holding capacity was higher in forest followed by barren land and the lowest in cultivated lands. At both soil depths, soils of cultivated land showed the highest values of bulk density (1.42 to $1.50g\;cm^{-3}$), followed by barren lands (1.37 to $1.46g\;cm^{-3}$) and the least (1.32 to $1.45g\;cm^{-3}$) in forest soils. Total porosity decreased with depth ranging from 40.24% to 41.53% in subsoils and from 42.04 to 43.23% in surface soil of cultivated and of planted forest sites respectively. The result further revealed that organic carbon (OC) and total nitrogen (TN) contents were higher in the planted forest soil than in other two land uses. The soils of all land uses under study are acidic in nature and the lowest pH was found in both surface and subsoils of barren land. Cultivated soil contained the highest amount of available P, Ca, Mg and K in both surface soil and subsoils. In contrast, barren site had the lowest contents of available P, Ca, Mg and K in both layers. The soil organic carbon (SOC) and total N storage were higher in planted forest than in barren and cultivated land uses.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.55-65
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• 2009

Annex I parties continued its consideration of how to address, the definitions, modalities, rules and guidelines for the treatment of Land Use, Land-use Change and Forestry (LULUCF) in the second commitment period of the Kyoto Protocol by the year of 2009. In the AWG-KP conference held in Accra, Ghana in 2008, four alternatives (gross-net carbon accounting, net-net with base year or base period accounting, net-net with forward looking baseline accounting, and land-based accounting method) for negotiations were decided in order to revise gross-net accounting method applied during the first commitment period of the Kyoto Protocol. In this study, alternative scenarios are set in consideration with reporting system (voluntary or compulsory), discount factors and cap about these three alternatives except for the method of net-net with forward looking baseline accounting, and then estimates the Removal Unit (RMU) among the countries. In the case that article 3.4 activities under the Kyoto Protocol revises from voluntary reporting to mandatory reporting, it is estimated that the loss of RMU would be huge in Russia, Australia, New Zealand, as well as Canada potentially. Net-net with base year or base period carbon accounting and land-based carbon accounting method have big difference of RMU in accordance with the base year or the base period. So the more unfavorable the country with a lot of old-age forests was, the closer the base year or period comes to the commitment period in the context of RMU. If it is getting lowered for the current rate of 85% in discount factors, RMU is getting higher to the whole countries. Therefore in Korea with little potential for afforestation and reforestation, there was the most sensitive response to the change of discount factors. Post-2012 LULUCF hereafter, it is strongly expected for the succession of current carbon accounting system which is voluntary reporting of gross-net carbon accounting and the activity for article 3.4. Other carbon accounting method is hard to accept in aspect that there is big differentiated interests among the countries and it is required enormous cost and time to develop reliable method. Provide for Post-2012 mandatory greenhouse gas reduction, Korea needs to have a competitive negotiation strategies differentiated from Annex I countries. The most reliable alternative would be to lower the discounting factors about the activities for forest management.

• Journal of Mushroom
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• v.7 no.1
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• pp.27-36
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• 2009

Pleurotus ferulae is an edible mushroom found on a medicinal plant, Ferula assa-foetida, in centeral China. This study was carried out to investigate the cultural characteristics of P. ferulae strains. Characteristics of mycelial growth were investigated for 5 strains of P. ferulae. All the 5 strains showed the best mycelial growth at $25^{\circ}C$ and their growth rate was very low at $35^{\circ}C$. The colony diameter reached to 45~72 mm after 7 days at $25^{\circ}C$. Malt extract agar medium was the best for mycelial growth of the species both in hyphal length and density. Mycelial growth was not affected by various pH from 6.0 to 8.0. An optimal carbon source was arabinose and an optimal nitrogen one was arginine. And an effective substrate for the mycelial growth was 8 to 2 mixture of oak sawdust and cottonseed meal.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.726-735
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• 2010

Publications with the data on allometric equation, biomass and productivity of major oak forests in Korea were reviewed. Different allometric equations of major oak species showed site- or speciesspecific dependences. The biomass of major oak forests varied with age, dominant species, and location. Aboveground tree biomass over the different oak species was expressed as a power equation of the stand age. The proportion of tree component (stem, branch and leaf) to total aboveground biomass differed among oak species, however, biomass ranked stem > branch > leaf in general. The leaf biomass allocation over the different oak species was expressed as a power equation of total aboveground biomass while there were no significant patterns of biomass allocation from stem and branch to the aboveground biomass. Tree root biomass continuously increased with the aboveground biomass for the major oak forests. The relationship between the root to shoot ratio and the aboveground tree biomass was expressed by a logarithmic equation for major oak forests in Korea. Thirteen sets of data were used for estimating the net primary production (NPP) and net ecosystem production (NEP) of oak forests. The mean NPP and NEP across different oak forests was 10.2 and 1.9 Mg C $ha^{-1}year^{-1}$. The results in biomass allocation, NPP and NEP generally make Korean oak forests an important carbon sinks.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.289-298
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• 2010

A number of characteristics of the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed, such as the lake's location at the edge of the Central Asian continuous permafrost zone, provide a unique opportunity to evaluate possible anthropogenic impacts in this remote area in northern Mongolia. In this study, we compared stream solute concentrations in six sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l watershed. Water samples were collected during the summer months between 2003 and 2005. Concentrations of $Cl^-$ ranged from 9.8 to $51.3\;{\mu}mol/L$; average nitrate concentrations were very low and ranged from undetectable to $1.1\;{\mu}mol/L$ and average ${SO_4}^{2-}$ concentration at sampling stations with minimal animal grazing ranged from 66 to $294\;{\mu}mol/L$. Average dissolved organic carbon (DOC) concentrations ranged from 642 to $1,180\;{\mu}mol$ C/L. We did not find statistically significant differences in DOC concentrations among the six streams, although DOC concentrations tended to be higher in the two northernmost streams, possibly related to differences in the active layer above the permafrost. Dissolved organic nitrogen (DON) concentrations were correlated with DOC concentration, and followed the same spatial pattern as those for DOC. In streams in this remote watershed, total dissolved nitrogen was made up of mostly organic N, as has been found for other regions distant from anthropogenic N sources. Overall, these results suggest that future research on the dynamics of DOC and DON in this watershed will be especially insightful in helping to understand how changes in climate and land use patterns will affect transformations, retention, and export of dissolved organic matter within these sub-watersheds in the Lake H$\ddot{o}$vsg$\ddot{o}$l region.

• Asian Journal of Atmospheric Environment
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• v.12 no.1
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• pp.1-16
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• 2018

Ground-level ozone ($O_3$) can be a menace for vegetation, especially in Asia where $O_3$ levels have been dramatically increased over the past decades. To ensure food security and maintain forest ecosystem services, such as nutrient cycling, carbon sequestration and functional diversity of soil biota, in the over-populated Asia, environmental standards are needed. To set proper standards, dose-response relationships should be established from which critical levels are derived. The predictor of the response in the dose-response relationship is an $O_3$ metric that indicates the dose level to which the plant has been exposed. This study aimed to review the relevant scientific literature and summarize the $O_3$ metrics used worldwide to provide insights for Asia. A variety of $O_3$ metrics have been used, for which we discuss their strengths and weaknesses. The most widely used metrics are based only on $O_3$ levels. Such metrics have been adopted by several regulatory agencies in the global. However, they are biologically irrelevant because they ignore the plant physiological capacity. Adopting AOT40 ($O_3$ mixing ratios Accumulated Over the Threshold of $40nmol\;mol^{-1}$) as the default index for setting critical levels in Asia would be a poor policy with severe consequences at national and Pan-Asian level. Asian studies should focus on flux-based $O_3$ metrics to provide relevant bases for developing proper standards. However, given the technical requirements in calculating flux-based $O_3$ metrics, which can be an important limitation in developing countries, no-threshold cumulative exposure indices like AOT0 should always accompany flux-based indices.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2004.11a
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• pp.139-143
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• 2004

To evaluate the biological and physiological response of Picea koraiensis Nakai to elevated $CO_2$ and nitrogen.3-year old seedlings were planted in an ambient and 700 ppm $CO_2$ at low (2mM $NH_4NO_3$) or high nitrogen (16mM $NH_4NO_3$) supplying treatments for 3 months. Photosynthetic parameters were measured monthly. Seedlings were harvested at monthly intervals and growth parameters of root system, stem and needle fractions were evaluated. The result showed that height of the seedlings grown at both of elevated $CO_2Xhigh$ nitrogen and elevated CO2×low nitrogen supplying treatments increased significantly more than that of at ambient CO2 treatments. Seedlings grown at elevated $CO_2Xhigh$ nitrogen produced more root biomass than at elevated $CO_2Xlow$ nitrogen and ambient $CO_2Xhigh$ nitrogen treatments. This result suggested that the root growth response of Picea koraiensis seedlings was greater in elevated $CO_2{\times}high$ nitrogen regime, which is very important for carbon sequestration in soil. $A_{max}$ of the seedlings grown at elevated $CO_2Xhigh$ nitrogen increased during the three months significantly, and $A_{max}$ of the seedlings grown at the other three treatments decreased significantly, suggesting that the interaction between elevated $CO_2$ and high nitrogen supplying stimulates the $A_{max}$ of Picea koraiensis. $A_{max}$ of the seedlings grown at elevated $CO_2Xlow$ nitrogen showed higher than other three treatments in the first month of the experiment, but decreased in succedent two months, suggesting that elevated $CO_2$ promotes the photosynthesis of the seedlings. However long term growth in elevated $CO_2Xlow$ nitrogen supplying condition resulted in an acclimatory decreased in leaf photosynthesis.

• Journal of agriculture & life science
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• v.50 no.1
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• pp.95-104
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• 2016

The objective of this paper is to develop volume equation of street tree and its carbon stock for urban forest in Seoul. To develop the volume equation by major species in Seoul, data for street trees were obtained from four-species (e.g. Gingko biloba, Platanus occidentalis, Zelkova serrata, and Metasequoia glyptostroboides), which accounted for 79% all street trees in Seoul. This study used a variable based on diameter on breast height and four equation for calculating volume. The coefficient of determination, bias, and root mean square error were used to evaluate the precision of four equations. From these methods, the most suitable equations for Platanus occidentalis was aDb, the other was aD+bD2; coefficient of determination upper on 0.873. From the volume equation developed in this research, the estimated carbon stock were derived as about 33,760tC for four-species of urban forest in Seoul. The results of this paper offered volume equation and carbon stock that present growth information for street trees in urban forestry and these can be made available for evaluating the management for carbon in settlement.

• Korean Journal of Remote Sensing
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• v.40 no.2
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• pp.203-217
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• 2024

The Land Use, Land-Use Change and Forestry (LULUCF) sector of the National Greenhouse Gas Inventory is crucial for obtaining data on carbon sinks, necessitating accurate estimations. This study analyzes cases of countries applying the LULUCF sector at the Tier 3 level to propose enhanced methodologies for carbon sink estimation. In nations like Japan and Western Europe, satellite spatial information such as SPOT, Landsat, and Light Detection and Ranging (LiDAR)is used alongside national statistical data to estimate LULUCF. However, in Korea, the lack of land use change data and the absence of integrated management by category, measurement is predominantly conducted at the Tier 1 level, except for certain forest areas. In this study, Space-borne LiDAR Global Ecosystem Dynamics Investigation (GEDI) was used to calculate forest canopy heights based on Relative Height 100 (RH100) in the cities of Icheon, Gwangju, and Yeoju in Gyeonggi Province, Korea. These canopy heights were compared with the 1:5,000 scale forest maps used for the National Inventory Report in Korea. The GEDI data showed a maximum canopy height of 29.44 meters (m) in Gwangju, contrasting with the forest type maps that reported heights up to 34 m in Gwangju and parts of Icheon, and a minimum of 2 m in Icheon. Additionally, this study utilized Ordinary Least Squares(OLS)regression analysis to compare GEDI RH100 data with forest stand heights at the eup-myeon-dong level using ArcGIS, revealing Standard Deviations (SDs)ranging from -1.4 to 2.5, indicating significant regional variability. Areas where forest stand heights were higher than GEDI measurements showed greater variability, whereas locations with lower tree heights from forest type maps demonstrated lower SDs. The discrepancies between GEDI and actual measurements suggest the potential for improving height estimations through the application of high-resolution remote sensing techniques. To enhance future assessments of forest biomass and carbon storage at the Tier 3 level, high-resolution, reliable data are essential. These findings underscore the urgent need for integrating high-resolution, spatially explicit LiDAR data to enhance the accuracy of carbon sink calculations in Korea.