• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1055-1063
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• 2002

In this paper, we have studied path selection problem using multiple metric. Current Internet selects a path using only one metric. The path selected by one metric is a best-effort service that can satisfy one requirements. In order to satisfy a call with various Qualify-of-Service(QoS) requirements, the path must satisfy multiple constraints. In many cases, path selection is NP-complete. The proposed algorithm is widest-least cost routing algorithm that selects a path based on cost metric which is basically a delay metric influenced by the network status. The proposed algorithm is a multiple metric path selection algorithm that has traffic distribution ability to select shortest path when network load is light and move traffic to other alternate path when the link load is high. We have compared the results with other routing algorithms.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1087-1093
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• 2010

The satellite thermal control H/W composed of two parallel channels working for heat pipe (HP) and phase change material (PCM) is suggested for the high heat dissipating component which works intermittently with short duty. In a limited point of view, the HP-PCM device is a kind of off-the-shelf component that requires no dedicated configuration and thermal designs to PCM. Therefore, it can be used with less impact on the program cost and schedule different from most of the PCM applications. In present study the typical honeycomb structure radiator applying the HP-PCM device is designed and the detail thermal math model is developed for numerical analyses. The result comparison between without and with PCM shows that the HP-PCM device redistributes the peak heat around the whole mission period through the alternate melting and freezing of PCM, and, as a result, the maximum and minimum temperatures are effectively alleviated. The drawback of PCM application due to low thermal conductivity can be successfully resolved by means of parallel arrangement of HP channel.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.330-335
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• 2008

This experiment was carried out to investigate the effects of insecticide control system in eggplant greenhouse. In all treatments, the average densities of Frankliniella occidentalis and Tetranychus urticae were $0.3{\sim}1.8$ and 0.0 per leaf at 28 days after treatment, respectively. These results indicate the alternate application of Abamectin EC and Spinosad GW can be useful in control for F. occidentalis and T. urticae in eggplant greenhouse. The density suppression effect against Liriomyza trifolii and Trialeurodes vaporariorum was maintained for 28 days after treatment, but control effect was low at 28 days after treatment.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1349-1359
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• 2016

Alternative control schemes for an Advanced High Temperature Reactor system consisting of a reactor, an intermediate heat exchanger, and a secondary heat exchanger (SHX) are presented in this paper. One scheme is designed to control the cold outlet temperature of the SHX ($T_{co}$) and the hot outlet temperature of the intermediate heat exchanger ($T_{ho2}$) by manipulating the hot-side flow rates of the heat exchangers ($F_h/F_{h2}$) responding to the flow rate and temperature disturbances. The flow rate disturbances typically require a larger manipulation of the flow rates than temperature disturbances. An alternate strategy examines the control of the cold outlet temperature of the SHX ($T_{co}$) only, since this temperature provides the driving force for energy production in the power conversion unit or the process application. The control can be achieved by three options: (1) flow rate manipulation; (2) reactor power manipulation; or (3) a combination of the two. The first option has a quicker response but requires a large flow rate change. The second option is the slowest but does not involve any change in the flow rates of streams. The third option appears preferable as it has an intermediate response time and requires only a minimal flow rate change.

• Journal of the Korean Applied Science and Technology
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• v.16 no.4
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• pp.273-279
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• 1999

In order to study a reversible photoisomerization of disperse red l(DR 1) attached on natural polymers, cellulose acetate containing DR l(DR 1/CA adduct) was prepared, and the changes of UV/VIS spectra of its solution(benzene, DMAc). thick film, and LB film were investigated by alternate irradiation with two different wave length lights. DR 1/CA adduct was prepared through tosylation of partially hydrolyzed cellulose acetate followed by reaction with DR 1 at $100^{\circ}C$ in pyridine. From the UV/VIS spectra of DR 1/CA adduct dissolved in DMAc solvent including phosphoglyceride before and after irradiation at 360nm and 45Onm, we found out the changes of UV/VIS spectra were reversible. In addition, the change of UV/VIS spectra of this adduct solution was strongly depended on the sorts of solvents and temperature. As the temperature was increased, UV/VIS spectra of this adduct solution in DMF showed blue shift. These results provided this solution could be applied to a temperature sensor. In the thick film case, we also obtained similar results with solution case. LB monolayer and trilayer from DR 1/CA adduct was obtained by scattering the solution including phosphoglyceride on water surface at the surface pressure of 8mN/m. After irradiation on that LB monolayer and trilayer, the reversible photoisomerization was also detected. From these results we concluded DR 1/CA adduct was suitable for the application to data storage and optical switch, etc.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.221-228
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• 2018

BACKGROUND: Spoilage fungi can reduce the shelf life of fresh fruits and cause economic losses by lowering quality. Especially, mulberry fruits have high sensitivity to fungal attack due to their high water content (> 70%) and soft texture. In addition, the surface of these fruits is prone to damage during harvesting and postharvest handling. However, any study on postharvest spoilage fungi in mulberry fruit has not been reported in Korea. This study aimed to examine the spoilage fungi occurring in mulberry fruits during storage after harvest. METHODS AND RESULTS: In this study, we isolated postharvest spoilage fungi from mulberry fruits stored in refrigerator (fresh fruits) and deep-freezer (frozen fruits) and identified them. In the phylogenetic analysis based on comparisons of the ITS rDNA sequences, the 18 spoilage fungi isolated from mulberry fruits and the 25 reference sequences were largely divided into seven groups that were subsequently verified by high bootstrap analysis of 73 to 100. Alternaria spp. including A. alternate and A. tenuissima, were the most frequently isolated fungi among the spoilage isolates: its occurrence was the highest among the 18 isolates (38.9%). CONCLUSION: The findings of this study will be helpful for increasing the shelf life of mulberry fruits through the application of appropriate control measures against infection by spoilage fungi during storage.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.70-79
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• 2022

Biodiesel production has attracted attention as a sustainable source of fuel and is a competitive alternate to diesel engines. The glycerol that is produced as a by-product is generally discarded as waste and can be converted to green chemicals such as acetins to increase bio-diesel profitability. Acetins find application in fuel, food, pharmaceutical and leather industries. Batch experiments and analysis have been previously conducted for synthesis of acetins using glycerol esterification reaction aided by sulfated metal oxide catalysts (SO₄^2-/CeO₂-ZrO₂). The aim of this study was to optimize process parameters: effects of mole ratio of reactants (glycerol and acetic acid), catalyst concentration and reaction temperature to maximize glycerol conversion/acetin selectivity. The optimum conditions for this reaction were determined using response surface methodology (RSM) designed as per a five-level-three-factor central composite design (CCD). Statistica software 10 was used to analyze the experimental data obtained. The optimized conditions obtained were molar ratio - 1:12, catalyst concentration - 6 wt.% and temperature -90 ℃. A packed bed reactor was fabricated and column studies were performed using the optimized conditions. The breakthrough curve was analyzed.

• IMMUNE NETWORK
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• v.23 no.1
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• pp.3.1-3.14
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• 2023

Microvilli are outer membrane organelles that contain cross-linked filamentous actin. Unlike well-characterized epithelial microvilli, T-cell microvilli are dynamic similar to those of filopodia, which grow and shrink intermittently via the alternate actin-assembly and -disassembly. T-cell microvilli are specialized for sensing Ags on the surface of Ag-presenting cells (APCs). Thus, these finger-shaped microprotrusions contain many signaling-related proteins and can serve as a signaling platforms that induce intracellular signals. However, they are not limited to sensing external information but can provide sites for parts of the cell-body to tear away from the cell. Cells are known to produce many types of extracellular vesicles (EVs), such as exosomes, microvesicles, and membrane particles. T cells also produce EVs, but little is known about under what conditions T cells generate EVs and which types of EVs are released. We discovered that T cells produce few exosomes but release large amounsts of microvilli-derived particles during physical interaction with APCs. Although much is unanswered as to why T cells use the same organelles to sense Ags or to produce EVs, these events can significantly affect T cell fate, including clonal expansion and death. Since TCRs are localized at microvilli tips, this membrane event also raises a new question regarding long-standing paradigm in T cell biology; i.e., surface TCR downmodulation following T cell activation. Since T-cell microvilli particles carry T-cell message to their cognate partner, these particles are termed T-cell immunological synaptosomes (TISs). We discuss the potential physiological role of TISs and their application to immunotherapies.

• Journal of Microbiology and Biotechnology
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• v.34 no.5
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• pp.1154-1163
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• 2024

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4'-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4',7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4',5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.

• Korean Journal of Environmental Agriculture
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• v.9 no.1
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• pp.15-22
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• 1990

The efects of application time on the persistence of chlorothalonil in sesame plants and its persistence in soil were studied in the field. A procedure was used which permited the analysis of residues of Chlorothalonil (DACONIL 2787) in sesame(Sesamum indicum L.)and soil. The procedure was based on the multiresidue analytical method using an polarized acetonitrile solution or acidified acetone as the extracting solvent. The DACONIL 2787 is separated from the fat in the extracts by using an activated alumina and Florisil chromatogaphic column. Residues of DACONIL 2787 were determined by subjecting the alternate eluate from the Florisil column to gas chromatographic analysis(ECD). Residue of chlorothalonil in sesame are proved to 0.06 ppm for six sprays, 3rd day before harvest The half-life of chlorothalonil in soil proved to be 8.9 days and residues of chlorothalonil was only 0.03 ppm 100 days after application of 15 ppm.