• Journal of Korean Society of Forest Science
• /
• v.99 no.1
• /
• pp.136-143
• /
• 2010

This study was conducted to provide basic information on the management of natural deciduous forests by presenting suitable stand density over time for natural deciduous forests in Pyungchang Area. The stand density index(SDI) for the sampling point was also computed. The cutting scenarios were adopted by considering the SDI estimated in the sampling point. And then, simulation cutting was enforced to the stand. Cutting scenarios consisted of three cutting levels, with the period of 5 years where each suitable cutting level of selection system will not have the SDI over the maximum SDI throughout 30 years and consider harvest after 30 years. As a result of the simulation cutting, it was found that removing 12% and 14% of basal area per each time kept proper stand density while removing 10% exceed to the adequate basis. From an economic point of view, it was concluded that removal 12% of basal area would be the most suit cutting level in selection system.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.5
• /
• pp.1339-1342
• /
• 2010

$^{31}P$ NMR and ESI-MS studies of $Cu^{2+}$ binding to Fenitrothion (FN) were performed by experimentally and theoretically. The calculated $^{31}P$ NMR chemical shifts for FN-$Cu^{2+}$ complexes are in good agreement with experimental chemical shifts in order, and the results present an important information for organophosphorus pesticide metal complexes. ESI-MS and low energy CID MS/MS experiments of FN-$Cu^{2+}$ complexes combined with accurate mass measurements give insight into the metal localization and allow unambiguous identification of fragments and hydrolysis products.

• Journal of Environmental Science International
• /
• v.11 no.6
• /
• pp.483-488
• /
• 2002

Suspended sediment outflows mainly by natural situation and artificial action and affects in down-stream. This research studied suspended sediments origination in forests size and mountain stream for natural situation, density for artificial action, and measured the size and possible quantity of suspended sediments origination and studied obstruction method of the generation by artificial action. As the result, I found that the size of generation is about 2~3% of forest size and the forest size which is affecting bare area of valley is about 1∼2ha. In addition, possible outflow segments quantity by artificial facilities is assumed to be maximum 200ton/ha and abstract of mountain incline for mountain development needs minimize bare area valley by make right angle with minimum size.

• Korean Journal of Veterinary Research
• /
• v.32 no.2
• /
• pp.245-250
• /
• 1992

This study was performed to demonstrate the presence of large granular lymphocyte(LGL) in Sprague-Dawley(SD) rats and morphologically observe NK cell and also establish the method of isolation of natural killer cell in SD rats. By percoll discontinuous density gradients centrifugation, highly enriched LGL population were shown to fraction 2(border line between 44.2% and 50.8%). LGL were shown to bind selectively to YAC1 mouse lymphoma cell. This fraction expressed very high NK cell cytolysis. Therefore, we thought that LGL have NK activity in SD rats. The Morphology of rat LGL is very similar to that of human LGL. These cells have an eccentric kidney-shaped nucleus. Their most distinctive feature was their cytoplasmic azurophilic granules. Another distinguishing feature of rat LGL was their high cytoplasmic : nuclear ratio. It was concluded that LGL played a role part in mediating natural killer activity in this species.

• Solar Energy
• /
• v.19 no.2
• /
• pp.29-36
• /
• 1999

Heat transfer characteristics of a low temperature latent heat storage system during the heat storage stage was examined for the circular finned tubes using fatty acid which shows the big density difference during melting as phase change materials. The heat storage vessel has the dimension of 530 mm height, 74 mm inside diameter and inner heat transfer tube is 480 mm in height and 13.5 mm outside diameter. Hot water was employed as the heat transfer fluid. During the heat storage stage, it was found that both conduction and natural convection were the major heat transfer mechanism. It was also found that the effect of natural convection on the heat transfer was more significant for the unfinned tube system than that for the finned tube system. The experimentally determined overall heat transfer coefficients were in the range of $50{\sim}250W/m^2K$ and the correlation for natural convection heat transfer as a function of Nusselt and Rayleigh number was proposed.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.8 no.1
• /
• pp.1-9
• /
• 2005

This study was conducted to establish a management plan for the Sangrim Woodlands restoration by analyzing the site characteristics of the Sangrim Woodlands Natural Monument(Natural Monument 154) in Hamyang-Gun, Gyoungsangnam-Do, Korea. Site preparation to enhance soil aeration should be applied because soil bulk density in all study sites was higher than soil compaction of natural forest soil area. Herbaceous plants could be introduced to hard soil strength for restoration of areas compacted by visitors. Also, visitors around forest areas should be restricted to enhance natural soil restoration. Soil pH in the Sangrim Woodlands was between 4.18 and 4.90. The values were lower than pH 5.34 of Korean forest soil originated from metamorphic parent materials. Lime fertilizer could be applied to reduce soil acidification in the woodlands. Short and long-term management plans such as periodical fertilizations to improve plant growth should be established to restore the Sangrim Woodlands which have high soil compaction, low soil pH and organic matter content.

• Steel and Composite Structures
• /
• v.33 no.2
• /
• pp.299-306
• /
• 2019

The natural fibre composites are termed as bio-composites. They have shown a promising replacement to the current carbon/glass fibre reinforced composites as environmental friendly materials in specific applications. Natural fibre reinforced composites are potential materials for various engineering applications in automobile, railways, building and Aerospace industry. The natural fibre selected to fabricate the composite material is plant-based fibre e.g., sisal fibre. Sisal fibre is a suitable reinforcement for use in composites on account of its low density, high specific strength, and high hardness. Epoxy is a thermosetting polymer which is used as a resin in natural fibre reinforced composites. Hand lay-up technique was used to fabricate the composites by reinforcing sisal fibres into the epoxy matrix. Composites were prepared with the unidirectional alignment of sisal fibres. Test specimens with different fibre orientations were prepared. The fabricated composites were tested for mechanical properties. Impact test, tensile test, flexural test, hardness test, compression test, and thermal test of composites had been conducted to assess its suitability in industrial applications. Scanning electron microscopy (SEM) test revealed the microstructural information of the fractured surface of composites.

• Journal of the Korean Magnetic Resonance Society
• /
• v.26 no.4
• /
• pp.40-45
• /
• 2022

A small cage-like molecule (2) composed of three aminomethyl pyrroles and two hexa-substituted benzenes has been prepared by reduction of its iminopyrrole analogue (1) using NaBH₄. It was revealed by ¹H NMR spectroscopic analyses that cage molecule 2 strongly binds the fluoride anion in polar DMSO-d₆ relative to CDCl₃. Compared to that of compound 1, the lowered affinity of 2 for the fluoride anion is attributable to its increased electron density resulting from the production of thesecondary amine groups.

• IMMUNE NETWORK
• /
• v.20 no.3
• /
• pp.22.1-22.21
• /
• 2020

In the progression of atherosclerosis, macrophages are the key immune cells for foam cell formation. During hyperlipidemic condition, phagocytic cells such as monocytes and macrophages uptake oxidized low-density lipoproteins (oxLDLs) accumulated in subintimal space, and lipid droplets are accumulated in their cytosols. In this review, we discussed the characteristics and phenotypic changes of macrophages in atherosclerosis and the effect of cytosolic lipid accumulation on macrophage phenotype. Due to macrophage plasticity, the inflammatory phenotypes triggered by oxLDL can be re-programmed by cytosolic lipid accumulation, showing downregulation of NF-κB activation followed by activation of anti-inflammatory genes, leading to tissue repair and homeostasis. We also discuss about various in vivo and in vitro models for atherosclerosis research and next generation sequencing technologies for foam cell gene expression profiling. Analysis of the phenotypic changes of macrophages during the progression of atherosclerosis with adequate approach may lead to exact understandings of the cellular mechanisms and hint therapeutic targets for the treatment of atherosclerosis.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.906-918
• /
• 2012

In this study, we compared with results simulated by EOS(Equation of State) using Peng-Robinson model and GERG-2004 model for estimating vapor pressure, latent heat of vaporation, liquid density, and binary isotherm vapor-liquid equilibrium on pure components composing natural gases. We obtained the simulated results that while EOS using GERG-2004 model is more accurate than EOS using Peng-Robinson model for estimating liquid density, but rather it is less accurate for estimating binary isotherm vapor-liquid equilibrium. On the other hand, the use of Costald model in EOS using Peng-Robinson model for increasing more accuracy to calculate liquid density is almost same as EOS using GERG-2004 model within the error of 1 % compared with experimental data. Also, we confirmed that on the estimation of binary isotherm vapor-liquid equilibrium, EOS using GERG-2004 model is more accurate than EOS using Peng-Robinson model, but they are almost same.