• Water Engineering Research
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• v.2 no.1
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• pp.63-72
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• 2001

The variation of sampling errors was characterized using the Waymire-Gupta-Rodriguez-Iturbe multi-dimensional rainfall model(WGR model). The parameters used for this study are those derived by Jung et al. (2000) for the Han River Basin using a genetic algorithm technique. The sampling error problems considered are those for using raingauge network, satellite observation and also for both combined. The characterization of sampling errors was done for each month and also for the downstream plain area and the upstream mountain area, separately. As results of the study we conclude: (1) The pattern of sampling errors estimated are obviously different from the seasonal pattern of monthly rainfall amounts. This result may be understood from the fact that the sampling error is estimated not simply by considering the rainfall amounts, but by considering all the mechanisms controlling the rainfall propagation along with its generation and decay. As the major mechanism of moisture source to the Korean Peninsula is obviously different each month, it seems rather normal to provide different pattern of sampling errors from that of monthly rainfall amounts. (2) The sampling errors estimated for the upstream mountain area is about twice higher than those for the down stream plain area. It is believed to be because of the higher variability of rainfall in the upstream mountain arean than in the down stream plain area.

• BMB Reports
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• v.48 no.9
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• pp.495-500
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• 2015

Up-regulation of cell adhesion molecules and proinflammatory cytokines contributes to enhanced monocyte adhesiveness and infiltration into the skin, during the pathogenesis of various inflammatory skin diseases, including atopic dermatitis. In this study, we examined the anti-inflammatory effects of butein, a tetrahydroxychalcone, and its action mechanisms using TNF-α-stimulated keratinocytes. Butein significantly inhibited TNF-α-induced ICAM-I expression and monocyte adhesion in human keratinocyte cell line HaCaT. Butein also decreased TNF-α-induced pro-inflammatory mediators, such as IL-6, IP-10 and MCP-1, in HaCaT cells. Butein decreased TNF-α-induced ROS generation in a dose-dependent manner in HaCaT cells. In addition, treatment of HaCaT cells with butein suppressed TNF-α-induced MAPK activation. Furthermore, butein suppressed TNF-α-induced NF-kappaB activation. Overall, our results indicate that butein has immunomodulatory activities by inhibiting expression of proinflammatory mediators in keratinocytes. Therefore, butein may be used as a therapeutic agent for the treatment of inflammatory skin diseases. [BMB Reports 2015; 48(9): 495-500]

• Applied Science and Convergence Technology
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• v.27 no.3
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• pp.47-51
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• 2018

We fabricated an anode-type ion beam source and studied its driving characteristics of the initial extraction of ions using two driving mechanisms: a diffusion phenomenon and a charge repulsion phenomenon. For specimen exposed to the ion beam in two methods, the surface impurity element was investigated by using X-ray photoelectron spectroscopy. Upon Ar gas injection for plasma generation the ion beam source was operated for 48 hours. We found a Fe 2p peak 5.4 at. % in the initial ions by the diffusion mechanism while no indication of Fe in the ions released in the charge repulsion mechanism. As for a long operation of 200 min, the temperature of ion beam sources was measured to increase at the rate of ${\sim}0.1^{\circ}C/min$ and kept at the initial value of $27^{\circ}C$ for driving by diffusion and charge repulsion mechanism, respectively. In this study, we confirmed that the ion beam source driven by the charge repulsion mechanism was very efficient for a long operation as proved by little electrode damage and thermal stability.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.180-185
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• 2012

Type 2 Diabetes Mellitus, a chronic metabolic disorder which results from a high blood glucose level, is one of the most prevalent and costly diseases of our time. Considering increasing rates of obesity and the aging population in Korea, the number of diabetic patients is likely to rise rapidly in the future. There are five conventional diabetic drugs which work through different mechanisms; sulfonylureas, biguanide, meglitinide, alpha-glucosidase inhibitors, and thiazolidinedione. Although they all have antidiabetic effects, some side effects such as hypoglycemia, weight gain and gastrointestinal intolerance are associated with them. Incretin based therapies, utilizing glucagon-like peptide-1 (GLP-1) and dipeptidyl peptidase-4 (DPP-4) inhibitors, which have a lower risk of adverse side effects, have recently been introduced. At present PPAR-targeting drugs are being actively developed. In this research review, particular emphasis has been placed on the current trends and possible biological targets for the new generation of antidiabetic drugs.

• BMB Reports
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• v.55 no.7
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• pp.342-347
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• 2022

Defense priming allows plants to enhance their immune responses to subsequent pathogen challenges. Recent reports suggested that acquired resistances in parental generation can be inherited into descendants. Although epigenetic mechanisms are plausible tools enabling the transmission of information or phenotypic traits induced by environmental cues across generations, the mechanism for the transgenerational inheritance of defense priming in plants has yet to be elucidated. With the initial aim to elucidate an epigenetic mechanism for the defense priming in plants, we reassessed the transgenerational inheritance of plant defense, however, could not observe any evidence supporting it. By using the same dipping method with previous reports, Arabidopsis was exposed repeatedly to Pseudomonas syringae pv tomato DC3000 (Pst DC3000) during vegetative or reproductive stages. Irrespective of the developmental stages of parental plants that received pathogen infection, the descendants did not exhibit primed resistance phenotypes, defense marker gene (PR1) expression, or elevated histone acetylation within PR1 chromatin. In assays using the pressure-infiltration method for infection, we obtained the same results as above. Thus, our results suggest that the previous observations on the transgenerational inheritance of defense priming in plants should be more extensively and carefully reassessed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1541-1548
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• 2004

A nano-stage simulation tool is developed for an advanced E-beam lithography system. Even if piezo-actuators are believed to be compatible fer the E-beam lithograpy system it is difficult to predict their characteristics due to their nonlinearities such as hysteresis and creep. In this paper, the nonlinear properties are modeled for a piezo-actuator by considering the voltage range and speed variations. The hysteresis is described as the first order differential equation with 24 sets of parameters and the creep is modeled as a time-dependent logarithmic function with 2 sets of a parameter. A two-axis nano stage with piezo-actuators are investigated for realizing nano scale motions. The characteristics of flexure guide mechanisms are analyzed based on the finite element method using the ANSYS software. The simulation tool for the nano stage is constructed by using the RecurDyn software. The dynamic response of the nano stage is obtained in simulations and compared with the experimental data.

• 연구논문집
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• s.23
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• pp.93-107
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• 1993

The chemistry and performance characteristics of the EBDS process have been introduced, in which experimental results from laboratory, test plant, and pilot plant studies agree very well and can be understood from detailed kinetic models. The parametric dependencies of the NOx and $SO_2$, removal yields on the input conditions have been discussed and formulated quantitatively. The process is best suited for flue gas with high $SO_2$, loadings. The operation conditions, such as dose, ammonia, and water additions, can be adjusted fast upon load changes. The process works waste water free and the major product is a mixture of ammonium nitrate and sulfate that can be used as fertilizer. The up-date results show that the EBDS technology is safe and competitive with other already well-established technologies. Due to these interesting features, the electron beam process has gained much international recognition. Demonstration units of 100MW have been proposed in the United States and Japan. Further pilot plants are under construction in Poland and China, countries that make abundant use of highsulfur coal. Additional research activities are under way to further improve the energy efficiency of process, and accelerator prices have been decreasing during the past 10 years. So the EBDS process has a good chance to start a new generation of emission-control technology.

• Korean journal of applied entomology
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• v.35 no.1
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• pp.74-79
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• 1996

General esterases were analysed quantitatively and qualitatively to see their role in deltamethrin resistance mechanisms of the diamondback moth, Plutella xylostella L. Selection with 0.1 g of deltamethrin in each generation induced the moth to decrease susceptibility to the insecticide and to increase esterase activities of the fourth instar larvae. Both characters were highly correlated so that the correlation coefficient (r) between LDSo @g) of deltamethrin and esterase activities (~M/min/pg) was 0.9918 (P=0.0082). Nondenaturing PAGE (6%) separated 17 esterase bands from the whole body extracts of the fourth instar larvae. Deltamethrin-selected populations had fewer esterase bands than had the unselected. Four esterase bands (E3, E4, Ell, and E13) were, however, specific to deltamethrin-selected populations.

• Journal of Communications and Networks
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• v.11 no.4
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• pp.368-374
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• 2009

This paper focuses on a distributed multiple spectrum pricing scheme to maximize system capacity in next generation multiaccess systems, where multimode user equipments (MUEs) can connect simultaneously to multiple base stations (BSs) with multiple radio access technologies (RATs). The multi-price based scheme provides a distributed decision making for an optimal solution where radio resource allocations are determined by each MUE, unlike most centralized mechanisms where BS controls the whole radio resource. By the proposed optimal solution, MUEs can decide their share of spectrum bands and power allocation according to the spectrum price of each RAT, and at the same time the multiaccess system can achieve maximized total throughput. Numerical analysis shows that the proposed scheme achieves the maximal capacity by distributed resource allocation for the multiaccess system.

• Resources Recycling
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• v.16 no.4
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• pp.47-60
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• 2007

Plastic supply and recycling are increasingly becoming matters of social concern. In our country, Extended Producer Responsibility(EPR) system has been adopted in 2003 to expand recycle and reuse of waste resources at producer side, and due to expansion of the EPR system, amount of the mixed plastic waste generation has been drastically increased. Plastic-plastic separation is most fundamental technique to achieve effective plastic recycling. This paper reviews recent developments in plastic-plastic separation techniques and describe future tasks. The mechanisms of each separation which contain gravity separation, electrostatic separation, flotation, and separation of automotive shredder residue are described, and commercial scale and lab-scale results are introduced.