• Korean Journal of Plant Taxonomy
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• v.31 no.4
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• pp.321-341
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• 2001

Phytoliths of leaf blades of Oryza were studied by light and scanning electron microscopy in order to assign the diagnostic character and taxonomic key for the genus. Some phytoliths such as stomatal apparatus, long-cell and short-cell, existing at the same position on the abaxial side of leaf blade, were intensively investigated because of their various forms documented in a previous study. These characters have value either for testing infrageneric classification or for identifying taxa within the genus. Stomatal phytolith is formed by integration of several kinds of sources, such as the guard and subsidiary cell and the papillae. The stomatal phytolith, characterized by not only the absence and presence of phytolith originated by the papillae developed on the guard and subsidiary cell but also their pattern of arrangement, shows various morphologies, and these features have congruent with the infrageneric classification such as section and/or series. Long-cell phytolith is characterized by the absence/presence, arrangement and morphology of phytoliths originated by the papillae on the cell surface. These features may hardly have any systematic relevance within the genus, but contain some informations for identifying of species. All of short-cell phytoliths found are silica body. They form various shapes like cross, bilobate, saddlelike and trilobate, and these features are consistent with infrageneric classification such as section and/or series. Also, some characters, the absence/presence of band of short cell phytolith within costal strip, the absence/presence of saddlelike phytolith within intercostal strip and the number of band of short cell phytolith within costal strip are various according to taxa, but these features do not fall into infrageneric classification. Some taxonomic keys on the phytoliths of stomatal, long-cell and short-cell were developed by their features, and the agreement between these characters and infrageneric classifications was also discussed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.164-170
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• 2020

The weather conditions, such as temperature, precipitation, and sunshine duration, play one of the key roles in Agriculture. In particular, extreme weather events have crucial impacts on growth and yields of crops. This study estimates statistics of extreme weather events in 167 Si-gun over South Korea derived from high-resolution(30 and 270m) topo-climatology model for key three meteorological variables(temperature, precipitation and sunshine duration). It is shown that the characteristic of each extreme weather frequency in the topo-climatology model is in good agreement with observation from Korean Meteorological Administration's Automatic Surface Observing System. Moreover, it is possible to analyze the statistics of extreme weather more realistically because this data can cover the weather at not-observed regions. Hence, this data is expected to be used as baseline data for assessing vulnerability to extreme weather and politic decisions for damage reduction in agricultural sector.

• Safety and Health at Work
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• v.13 no.4
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• pp.493-499
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• 2022

Background: The purpose of this study is to construct a job-exposure matrix for lead that accounts for industry and work processes within industries using a nationwide exposure database. Methods: We used the work environment measurement data (WEMD) of lead monitored nationwide from 2015 to 2016. Industrial hygienists standardized the work process codes in the database to 37 standard process and extracted key index words for each process. A total of 37 standardized process codes were allocated to each measurement based on an automated key word search based on the degree of agreement between the measurement information and the standard process index. Summary statistics, including the arithmetic mean, geometric mean, and 95th percentile level (X95), was calculated according to industry, process, and industry process. Using statistical parameters of contrast and precision, we compared the similarity of exposure groups by industry, process, and industry process. Results: The exposure intensity of lead was estimated for 583 exposure groups combined with 128 industry and 35 process. The X95 value of the "casting" process of the "manufacture of basic precious and non-ferrous metals" industry was 53.29 ㎍/m³, exceeding the occupational exposure limit of 50 ㎍/m³. Regardless of the limitation of the minimum number of samples in the exposure group, higher contrast was observed when the exposure groups were by industry process than by industry or process. Conclusion: We evaluated the exposure intensities of lead by combination of industry and process. The results will be helpful in determining more accurate information regarding exposure in lead-related epidemiological studies.

• Resources Recycling
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• v.33 no.2
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• pp.62-72
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• 2024

Although the Paris Agreement in 2015 aimed to limit global temperature increases to below 2℃ and eventually to 1.5℃ to address the climate crisis, global temperature continues to rise. Developed countries have proposed a circular economy as a major strategy to tackle this issue. Detailed implementation methods include reusing, remanufacturing, recycling, and energy recovery. Remanufacturing has a greater potential to achieve high added value and carbon neutrality than other resource circulation methods. However, currently, no standardized method for quantitatively evaluating the greenhouse gas (GHG) reduction effects of remanufacturing exists. This study compares and analyzes recent research trends since 2020 on the calculation of GHG emission reduction effects from remanufacturing. It also examines international standards for environmental impact assessment, including GHGs and environmental performance labeling systems. This study derives the key factors for standardizing the calculation of the GHG emission reduction effects of remanufactured products.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.12
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• pp.583-591
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• 2020

Employability has recently become the first target of the national higher education. Its model has been updated to catch the new trend of Industry 4.0. This paper aims at analyzing and ranking the determinants of undergraduate employability, focusing on business and economics majors in Ho Chi Minh City, Vietnam. In-depth interviews with content analysis have been primarily conducted to reach an agreement on a key group of factors: human capital, social capital, and identity. The Stochastic Fractal Search Algorithm (SFSA) is then applied to rank the sub-factors. Human capital is composed of three major elements: attitude, skill, and knowledge. Social capital is approached at both structural and cognitive aspects with three typical types: bonding, bridging, and linking. The analysis has confirmed the change of priority in employability determinants. Human capital is still a driver but the priority of attitude has been confirmed in the contemporary context. Then, social capital with the important order of linking, bridging, and bonding is emphasized. Skill, knowledge, and identity share the least weight in the model. It is noted that identity is newly proposed in the model but a certain role has been found. The findings are crucial for education strategies to enhance university graduate employability.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1141-1148
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• 2008

Geometry optimizations and electronic structure calculations are reported for meso-tetraphenyl porphyrin (TPP) and a series of meso-substituted catecholic porphyrins (KP99150, KP99151, KP99152, KP99153, and KP99090) using density functional theory (DFT). The calculated B3LYP//RHF bond lengths are slightly longer than those of LSDA//RHF. The calculated electronic structures clearly show that TPP and meso-catecholic group contribute to π-electron conjugation along porphyrin ring for HOMO and LUMO, significantly reduced the HOMO-LUMO gap. The wavelength due to B3LYP energy gaps is favored with experimental value in Soret (B), and LSDA energy gaps are favored with experimental value in visible bands (Q). The electronic effect of the catecholic groups is to reduced energies of both the HOMOs and LUMOs. However, the distortion of porphyrin predominantly raises the energies of the HOMOs, so the net result is a large drop in HOMO and smaller drop in LUMO energies upon meso-substituted catecholic group of the porphyrin macrocycle as shown in KP99151 and KP99152 of Figure 5(a). These results are in reasonable agreement with normal-coordinate structural decomposition (NSD) results. The HOMO-LUMO gap is an important factor to consider in the development of photodynamic therapy (PDT).

• Journal of Computational Design and Engineering
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• v.3 no.4
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• pp.349-362
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• 2016

The numerical solutions of unsteady hydromagnetic natural convection Couette flow of a viscous, incompressible and electrically conducting fluid between the two vertical parallel plates in the presence of thermal radiation, thermal diffusion and diffusion thermo are obtained here. The fundamental dimensionless governing coupled linear partial differential equations for impulsive movement and uniformly accelerated movement of the plate were solved by an efficient Finite Element Method. Computations were performed for a wide range of the governing flow parameters, viz., Thermal diffusion (Soret) and Diffusion thermo (Dufour) parameters, Magnetic field parameter, Prandtl number, Thermal radiation and Schmidt number. The effects of these flow parameters on the velocity (u), temperature (${\theta}$) and Concentration (${\phi}$) are shown graphically. Also the effects of these pertinent parameters on the skin-friction, the rate of heat and mass transfer are obtained and discussed numerically through tabular forms. These are in good agreement with earlier reported studies. Analysis indicates that the fluid velocity is an increasing function of Grashof numbers for heat and mass transfer, Soret and Dufour numbers whereas the Magnetic parameter, Thermal radiation parameter, Prandtl number and Schmidt number lead to reduction of the velocity profiles. Also, it is noticed that the rate of heat transfer coefficient and temperature profiles increase with decrease in the thermal radiation parameter and Prandtl number, whereas the reverse effect is observed with increase of Dufour number. Further, the concentration profiles increase with increase in the Soret number whereas reverse effect is seen by increasing the values of the Schmidt number.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.461-472
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• 2010

This paper investigates the behavior of precast concrete (PC) shear walls with a new vertical connections for a fast remodeling construction. The C-type vertical connections for the PC wall systems are proposed for transfer of bending moment between top and bottom walls in the vertical direction while a shear key in the center of wall is prepared to transfer shear forces by bearing action. The proposed vertical connections allows easy fabrication thanks to slots at the edges of wall in opposite directions. The plane PC wall systems subject to lateral load are compared with ordinary wall systems by investigating the effects of connection on the stiffness, strength, ductility, and failure modes of whole systems. The load-displacement relationship and influence of premature failure of connections are examined. The experimental test showed that the longitudinal reinforcing steel bars placed at the edges of walls yielded first and the ultimate deformation were terminated due to premature failure of connections. The diagonal reinforcements for efficient shear transfer in the walls were not effective. The strength and deformation obtained through the section analysis were generally in agreement with the experimental data, and indicated that. Gap opening contributed to the deformation behavior more than any other factors.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.42.2-43
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• 2015

Massive stars play a major role in the interstellar energy budget and the shaping of the galactic environment. The water molecule is thought to be a sensitive tracer of physical conditions and dynamics in star-forming regions because of its large abundance variations between hot and cold regions. Herschel/HIFI allows us to observe the multiple rotational transitions of H2O including the ground-state levels, and its isotopologues toward high-mass star-forming regions in different evolutionary stages. Photodissociation regions (PDRs) are also targeted to investigate the distribution of water and its chemistry. We present line profiles and maps of H2O using data from two guaranteed-time key programs "Water In Star-forming regions with Herschel" and "Herschel observations of EXtra-Ordinary Sources". We analyze the temperature and density structures using LTE and non-LTE methods. We also estimate turbulent and expansion velocities, and abundance of water in the inner and outer envelopes using the 1D radiative transfer code. Around high-mass protostars we find H2O abundances of ~10-8-10-9 for the outer envelope and ~10-4-10-5 for the inner envelope, and expansion and turbulent velocities range from 1.0 km s-1 to 2.0 km s-1. The abundances and kinematic parameters of the sources do not show clear trends with evolutionary indicators. The Herschel/HIFI mapping observations of H2O toward the Orion Bar PDR show that H2O emission peaks between the shielded dense gas and the radicals position, in agreement with the theoretical and the observational PDR structure. The derived H2O abundance is ~10-7 and peaks at the depth of AV ~8 mag from the ionization front. Together with the low ortho-to-para ratio of H2O (~1) presented by Choi et al. (2014), our results show that the chemistry of water in the Orion Bar is dominated by photodesorption and photodissociation.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.10
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• pp.1087-1092
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• 2015

It was diversified demand for a wireless network to the rapid growth of the Internet, the time and space that are not in the new level of Internet technology, limits the Ad-hoc networks are needed. Ad-hoc networks do not communicate with the central station, each of the mobile nodes included in the network communicate with each other by the relay role. In recent years, the Ad-hoc wireless networks in a variety of routing protocols and network security, research is actively underway for the authentication method, but the security of wireless Internet and Ad-hoc networks, certification is incomplete situation. This paper considers the authentication and key agreement technique applicability of the USIM card using the DSR routing protocol of the Java Card and Ad-hoc networks, we propose a secure authentication mechanism between the mobile node.