• Korean Journal of Metals and Materials
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• v.46 no.1
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• pp.44-51
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• 2008

The effects of magnetic powder size on electromagnetic wave absorption characteristics in Fe-6.5Si-0.9Cr(wt%) alloy flakes/polymer composite sheets available for quasi-microwave band have been investigated. The composite sheet including small magnetic flakes with the size less than $26{\mu}m$ exhibited high power loss in the GHz frequency range as compared with the sheets having large alloy flakes of $45{\sim}75{\mu}m$. Moreover, both the complex permeability and the loss factor increased with the decrease in size of the alloy flakes. The large power loss of the sheets containing small magnetic flakes was attributed to the high complex permeability, especially their imaginary part. The high complex permeability of the sheets composed of small flakes was considered to be due to the highly thin shape of the flakes inducing low eddy-current loss.

• Asia-Pacific Journal of Business
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• v.11 no.1
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• pp.115-143
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• 2020

Purpose - The purpose of this study is to expand the taxpayer's rights protections, which are covered in the previous studies, and to suggest ways to increase tax inspection efficiency as a way to induce fidelity reporting under the final tax return system and to lower tax compliance costs. Design/methodology/approach - The tax audit is a necessary system for the taxpayer to induce self-reporting in a sincere manner, but it is necessary to harmonize the realization of fair taxation and the rights of taxpayers because it is likely to infringe taxpayer rights in the process. Research implications or Originality - The purpose of this study is as follows. First, the government will seek ways to improve tax investigations to strengthen the protection of taxpayers' rights by increasing the fairness and procedural transparency of the current tax investigation system, as pointed out in the National Tax Administration Reform T / F. Second, we will consider ways to enhance the effectiveness of tax audit as a means of inducing faithful tax in Korea's tax system, which assumes sincere taxpayers.

• Korean Journal of Materials Research
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• v.32 no.6
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• pp.307-312
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• 2022

Metal halide perovskite (MHP) nanocrystals (NCs) have emerged as promising materials for various optoelectronic applications including photovoltaics, light-emitting devices, and photodetectors because of their high absorption coefficient, high diffusion length, and photoluminescence quantum yield. However, understanding the morphological evolution of the MHP NCs as well as their controlled assembly into optoelectronic devices is still challenging and will require further investigation of the colloidal chemistry. In this study, we found that the amount of n-octylamine (the capping agent) plays a crucial role in inducing further growth of the MHP NCs into one-dimensional nanowires during the aging process. In addition, we demonstrate that the dielectrophoresis process can permit self-alignment of the MHP nanowires with uniform distribution and orientation on interdigitated electrodes. A strong light-matter interaction in the MHP NWs array was observed under UV illumination, indicating the photo-induced activation of their luminescence and electrical current in the self-aligned MHP nanowire arrays.

• Smart Structures and Systems
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• v.29 no.4
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• pp.589-598
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• 2022

Timber structures are susceptible to structural damages caused by variations in moisture content (MC), inducing severe durability deterioration and safety issues. Therefore, it is of great significance to detect MC levels in timber structures. Compared to current methods for timber MC detection, which are time-consuming and require bulky equipment deployment, Lead Zirconate Titanate (PZT)-enabled stress wave sensing combined with statistic machine learning classification proposed in this paper show the advantage of the portable device and ease of operation. First, stress wave signals from different MC cases are excited and received by PZT sensors through active sensing. Subsequently, two non-baseline features are extracted from these stress wave signals. Finally, these features are fed to a statistic machine learning classifier (i.e., naïve Bayesian classification) to achieve MC detection of timber structures. Numerical simulations validate the feasibility of PZT-enabled sensing to perceive MC variations. Tests referring to five MC cases are conducted to verify the effectiveness of the proposed method. Results present high accuracy for timber MC detection, showing a great potential to conduct rapid and long-term monitoring of the MC level of timber structures in future field applications.

• BMB Reports
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• v.56 no.9
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• pp.508-513
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• 2023

The phytochemical quercetin has gained attention for its anti-inflammatory and anti-tumorigenic properties in various types of cancer. Tumorigenesis involves the aberrant regulation of kinase/phosphatase, highlighting the importance of maintaining homeostasis. Dual Specificity Phosphatase (DUSP) plays a crucial role in controlling the phosphorylation of ERK. The current study aimed to clone the DUSP5 promoter, and investigate its transcriptional activity in the presence of quercetin. The results revealed that quercetin-induced DUSP5 expression is associated with the serum response factor (SRF) binding site located in the DUSP5 promoter. The deletion of this site abolished the luciferase activity induced by quercetin, indicating its vital role in quercetin-induced DUSP5 expression. SRF protein is a transcription factor that potentially contributes to quercetin-induced DUSP5 expression at the transcriptional level. Additionally, quercetin enhanced SRF binding activity without changing its expression. These findings provide evidence of how quercetin affects anti-cancer activity in colorectal tumorigenesis by inducing SRF transcription factor activity, thereby increasing DUSP5 expression at the transcriptional level. This study highlights the importance of investigating the molecular mechanisms underlying the anti-cancer properties of quercetin, and suggests its potential use in cancer therapy.

• International Journal of Oral Biology
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• v.49 no.1
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• pp.10-17
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• 2024

Glutamate-mediated oxidative stress causes neuronal cell death by increasing intracellular Ca²⁺ uptake, reactive oxidative species (ROS) generation, mitogen-activated protein kinase (MAPK) activation, and translocation of apoptosis-inducing factor (AIF) to the nucleus. In the current study, we demonstrated that corydaline exerts potent neuroprotective effects against glutamate-induced neurotoxicity. Treatment with 5 mmol/L glutamate increased cellular Ca²⁺ influx, ROS generation, MAPK activation, and AIF translocation. In contrast, corydaline treatment decreased cellular Ca²⁺ influx and ROS generation. Western blot analysis revealed that glutamate-mediated MAPK activation was attenuated by corydaline treatment. We further demonstrated that corydaline treatment inhibited the glutamate-mediated translocation of AIF to the nucleus. We propose that corydaline is a promising lead structure for the development of safe and effective neuroprotectants.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.2
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• pp.95-101
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• 2005

In the heart, $Na^{+}-Ca^{2+}$ exchange (NCX) is the major $Ca^{2+}$ extrusion mechanism. NCX has been considered as a relaxation mechanism, as it reduces global $[Ca^{2+}]_i$ raised during activation. However, if NCX locates in the close proximity to the ryanodine receptor, then NCX would curtail $Ca^{2+}$ before its diffusion to global $Ca^{2+}_i$ This will result in a global $[Ca^{2+}]_i$ decrease especially during its ascending phase rather than descending phase. Therefore, NCX would decrease the myocardial contractility rather than inducing relaxation in the heart. This possibility was examined in this study by comparing NCX-induced extrusion of $Ca^{2+}$ after its release from SR in the presence and absence of global $Ca^{2+}_i$ transient in the isolated single rat ventricular myocytes by using patch-clamp technique in a whole-cell configuration. Global $Ca^{2+}_i$ transient was controlled by an internal dialysis with different concentrations of BAPTA added in the pipette. During stimulation with a ramp pulse from +100 mV to -100 mV for 200 ms, global $Ca^{2+}_i$ transient was suppressed only mildly, and completely at 1 mmol/L, and 10 mmol/L BAPTA, respectively. In these situations, ryanodine-sensitive inward NCX current was compared using $100{\mu}mol/L$ ryanodine, $Na^+$ depletion, 5 mmol/L $NaCl_2$ and $1{\mu}mol/L$ nifedipine. Surprisingly, the result showed that the ryanodine-sensitive inward NCX current was well preserved after 10 mmol/L BAPTA to 91 % of that obtained after 1 mmol/L BAPTA. From this result, it is concluded that most of the NCX-induced $Ca^{2+}$ extrusion occurs before the $Ca^{2+}$ diffuses to global $Ca^{2+})i$ in the rat ventricular myocyte.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.2
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• pp.93-101
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• 2002

We have proposed and fabricated two lateral type field emission diodes, poly-Si emitter by utilizing the local oxidation of silicon (LOCOS) and GaN emitter using metal organic chemical vapor deposition (MOCVD) process. The fabricated poly-Si diode exhibited excellent electrical characteristics such as a very low turn-on voltage of 2 V and a high emission current of $300{\;}\bu\textrm{A}/tip$ at the anode-to-cathode voltage of 25 V. These superior field emission characteristics was speculated as a result of strong surface modification inducing a quasi-negative electron affinity and the increase of emitting sites due to local sharp protrusions by an appropriate activation treatment. In respect, two kinds of procedures were proposed for the fabrication of the lateral type GaN emitter: a selective etching method with electron cyclotron resonance-reactive ion etching (ECR-RIE) or a simple selective growth by utilizing $Si_3N_4$ film as a masking layer. The fabricated device using the ECR-RIE exhibited electrical characteristics such as a turn-on voltage of 35 V for $7\bu\textrm{m}$ gap and an emission current of~580 nA/l0tips at anode-to-cathode voltage of 100 V. These new field emission characteristics of GaN tips are believed to be due to a low electron affinity as well as the shorter inter-electrode distance. Compared to lateral type GaN field emission diode using ECR-RIE, re-grown GaN emitters shows sharper shape tips and shorter inter-electrode distance.

• The Plant Pathology Journal
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• v.33 no.3
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• pp.249-263
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• 2017

This study aims to examine the potential reasons for the current prevalence of the fusarium wilt in the oriental melon. Twenty-seven Fusarium isolates obtained from oriental melon greenhouses in 2010-2011 were identified morphologically and by analysis of elongation factor-1 alpha gene (EF-$1{\alpha}$) and internal transcribed spacer (ITS) rDNA sequences as 6 Fusarium species (8 isolates of F. oxysporum, 8 F. commune, 5 F. proliferatum, 3 F. equiseti, 2 F. delphinoides, and 1 F. andiyazi), which were classified as same into 6 EF-$1{\alpha}$ sequence-based phylogenetic clades. Pathogenicity of the Fusarium isolates on the oriental melon was highest in F. proliferatum, next in F. oxysporum and F. andiyazi, and lowest in the other Fusarium species tested, suggesting F. proliferatum and F. oxysporum were major pathogens of the oriental melon, inducing stem rots and vascular wilts, respectively. Oriental melon and watermelon were more susceptible to F. oxysporum than shintosa and cucumber; and cucumber was most, oriental melon and watermelon, medially, and shintosa was least susceptible to F. proliferatum, whose virulence varied among and within their phylogenetic subclades. Severe root-knot galls were formed on all the crops infected with Meloidogyne incognita; however, little indication of vascular wilts or stem and/or root rots was shown by the nematode infection. These results suggest the current fungal disease in the oriental melon may be rarely due to virulence changes of the fusarium wilt pathogen and the direct cause of the severe root-knot nematode infection, but may be potentially from other Fusarium pathogen infection that produces seemingly wilting caused by severe stem rotting.

• Archives of design research
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• v.14 no.2
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• pp.7-14
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• 2001

Facing the 21th century, the cultural era, a lot of people show much more concern on cultural products than before. These cultural products can be regarded as our national countenance because they might contain the national tradition and spirit. So, it is quite obvious that the image of a product will be directly related to the national image. The current problems of developing cultural products in Korea are underdeveloped product design and technique, and widespread of poor quality products. Fist of all, it needs to develop competitive designs by reflecting cultural aspects in each product, based on the specialized research and information on our culture. And it is important to invest in developing materials and skills for mass production and the improvement that can excel the past. Also, there are needs to reform the sales structure to connect producers and consumers directly, not through the wholesalers who cause the price rising. Finally, museums as well as government should cope with this cultural competitive era actively by giving the continuous cultural education and inducing the participation from citizens.