• 비파괴검사학회지
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• 제5권2호
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• pp.5-11
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• 1986

In recent years the acoustic emission technique has been increasingly applied for detecting flaw s and cracks in materials either under testing or in service. It is important that what is the origin of AE signals detected by AE transducers. The purpose of this paper is to detect AE source on ductile material such as pressure vessel steel, A533B. As the results of experimentation, the increase of AE events number is proportional to the increase of the volume of plain strain zone. The origin of AE signals is fracture of MnS inclusions which have small amplitude of AE waves.

• E2M - 전기 전자와 첨단 소재
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• 제7권1호
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• pp.42-48
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• 1994

The preventive diagnosis technique for power system is being highlighted as a research area for deterioration of insulation in machinery because of high-voltage power system. We make efforts to develop not only diagnosis of aging state but also detection of defects in the initial stage from preventive diagnosis technique. Especially, partial discharge is actively studied as a non-destructive diagnosis technique and very useful because partial discharge measurement reduces damage than conventional diagnosis technique. The loaded stress during this test is smaller than that of other diagnosis techniques. But the continuous research for various complicated analysis method is required because partial discharge has very small signals and its signals have complex forms. In this paper, the measurement of partial discharge was investigated and studied on many specimens with void. We made samples having artificial voids and measured partial discharge. In order to use as a practical diagnosis technique, we studied ways of measurement, measured illustrations and types of partial discharge which could be used in order to diagnose defects of power machinery.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1999년도 특별강연 및 춘계학술발표대회 개요집
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• pp.241-244
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• 1999

The purpose of this study is to examine the characteristics of stress corrosion cracking(SCC) and acoustic emission(AE) signals for the weld HAZ of HT-60 steel under corrosion control in synthetic seawater. Corrosive environment was controlled by potentiostat, and SCC experiment was conducted using a slow strain rate test method at strain rate of 10$^{-5}$ /sec. In order to verify the miroscopic fracture behaviour of the weldment during SCC phenomena, AE test was done simultaneously. Besides, correlationship between mechanical parameters and AE ones was investigated. In case of the parent, reduction of area(ROA) at -0.5V was samller than any other applied voltage such as -0.8V and -1.1V. In addition, reduction of area for the PWHT specimens at -0.8mV was larger than that of the weldment due to the softening effect according to PWHT. In case of the weldment, a lots of events was produced because of the singularities of the weld HAZ compared with the parent.

• 한국산학기술학회논문지
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• 제7권1호
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• pp.52-56
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• 2006

본 논문에서는 산악지형이 많은 한반도에서 전파의 다중경로 전달 특성을 분석하여 최적의 레이다 운용 사이트를 선정하고 레이다에 발생되는 전파를 효율적으로 관리함으로써 레이다 운용을 적에게 최소로 노출시켜 대방사미사일의 공격을 피하면서 원하는 정보를 충분히 획득하는 전자보호 기술에 대해서 기술하였다. 또한 다중 경로에 의한 전파의 위상 특성을 분석하여 전력밀도의 변화를 분석하였다.

• Molecules and Cells
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• 제43권2호
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• pp.114-120
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• 2020

Drosophila hematopoiesis is comparable to mammalian differentiation of myeloid lineages, and therefore, has been a useful model organism in illustrating the molecular and genetic basis for hematopoiesis. Multiple novel regulators and signals have been uncovered using the tools of Drosophila genetics. A Runt domain protein, lozenge, is one of the first players recognized and closely studied in the hematopoietic lineage specification. Here, we explore the role of lozenge in determination of prohemocytes into a special class of hemocyte, namely the crystal cell, and discuss molecules and signals controlling the lozenge function and its implication in immunity and stress response. Given the highly conserved nature of Runt domain in both invertebrates and vertebrates, studies in Drosophila will enlighten our perspectives on Runx-mediated development and pathologies.

• Biomolecules & Therapeutics
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• 제31권4호
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• pp.395-401
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• 2023

Innate immunity is a first line defence system in the body which is for sensing signals of danger such as pathogenic microbes or host-derived signals of cellular stress. Pattern recognition receptors (PRR's), which present in the cell memebrane, are suspect the infection through pathogen-associated molecular patterns (PAMP), and activate innate immunity with response to promote inflammation via inflammatory cells such as macrophages and neutrophils, and cytokines. Inflammasome are protein complexes which are part of innate immunity in inflammation to remove pathogens and repair damaged tissues. What is the important role of inflammation in disease? In this review, we are focused on the action mechanism of NLRP3 inflammasome in inflammatory diseases such as asthma, atopic dermatitis, and sepsis.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2021년도 춘계학술대회
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• pp.60-60
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• 2021

Non-alcoholic fatty liver disease (NAFLD), especially including non-alcoholic steatohepatitis (NASH) is one of the common diseases with 25% of prevalence globally, but there is no thera-peutic access available. Amomum villosum var. xanthioides (Wall. ex Baker) T.L.Wu & S.J.Chen (AX), which is a medicinal herb and traditionally used for treating digestive tract disorders in Asia countries. We aimed to examine pharmacological effects of ethyl acetate fraction of AX (AXEF) against ER stress-induced NASH mice model using C57/BL6J male mice by tunicamycin (TM, 2 mg/kg) injection focusing on the oxidative stress. Mice were orally administrated AXEF (12.5, 25, or 50 mg/kg), silymarin (50 mg/kg) or distilled water daily for 5 days, and outcomes for fatty liver, inflammation, and oxidative stress were measured in serum or liver tissue levels. AXEF drastically attenuated hepatic ER stress-induced NASH which were evidenced by decreases of li-pid droplet accumulations, serum liver enzymes, hepatic inflammations, and cell death signals in the hepatic tissue or serum levels. Interestingly, AXEF showed potent antioxidant effects by quenching of reactive oxidative stress and its final product of lipid peroxide in the hepatic tissue, specifically increase of metallothionein (MT). To confirm underlying actions of AXEF, we ob-served that AXEF increase MT1gene promoter activities in the physiological levels. Collectively, AXEF showed antioxidant properties on TM-induced ER stress of NASH by enhancement of MTs.

• 한국게임학회 논문지
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• 제13권5호
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• pp.73-80
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• 2013

NUI(Natural User Interface)는 별도의 입출력 장치 없이 사용자 자신의 음성/신체부위 등을 사용하여 주변 디지털 기기를 제어할 수 있도록 하는 기술이다. 본 논문에서는 NUI가 적용된 스마트 공간에서 신체를 직접적으로 사용하는 체감형 게임을 실행하는 사용자를 대상으로 연구를 진행하였다. 게임 사용자의 스트레스 발생 여부를 알아내기 위하여 게임 시행 전과 후로 나누어 각각 60초에 걸쳐서 심전도를 측정하였고, 측정된 신호를 개량된 Random Forest 알고리즘으로 분석하였다. 교사학습 방식에 의한 실험을 위하여 사용자는 자신의 스트레스 발생 여부를 별도로 입력하여 저장하도록 하였으며, 실험결과 개량된 알고리즘이 기존의 알고리즘보다 1.04% 높은 정확도를 보여주었다.

• 한국군사과학기술학회지
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• 제18권6호
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• pp.789-796
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• 2015

Fighter pilot's ability to maintain both mental and physical capabilities in highly stressful situations is important for aviation safety as well as mission performance because pilot may confront frequently unexpected physical and psychological stimulation. Cumulative psychological stress and physical fatigue can be causes of mood distortion, declined alertness, and can lead to reduction of combat capability. We have investigated bio-signals and performance tests to monitor stress and fatigue levels, and developed a system to evaluate aviation mission suitability before flight. This study elucidated that stress and fatigue level of pilot can be monitored by psychomotor cognitive test(PCT) and heart rate variability(HRV), and that the best of reference for aviation mission suitability was confidential interval obtained from cumulative data of individuals. The system to evaluate aviation mission suitability was constructed with measuring part with PCT and HRV and control part with DB and algorithm.

• Molecules and Cells
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• 제26권4호
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• pp.323-328
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• 2008

Eukaryotic cells continuously integrate intrinsic and extrinsic signals to adapt to the environment. When exposed to stressful conditions, cells activate compartment-specific adaptive responses. If these are insufficient, apoptosis ensues as an organismal defense line. The mechanisms that sense stress and set the transition from adaptive to maladaptive responses, activating apoptotic programs, are the subject of intense studies, also for their potential impact in cancer and degenerative disorders. In the former case, one would aim at lowering the threshold, in the latter instead to increase it. Protein synthesis, consuming energy for anabolic processes as well as for byproducts disposal, can be a significant source of stress, particularly when difficult-to-fold proteins are produced. Recent work from our and other laboratories on the differentiation of antibody secreting cells, revealed a regulatory circuit that integrates protein synthesis, secretion and degradation (proteostasis), into cell lifespan determination. The apoptotic elimination - after an industrious, yet short lifetime - of terminal immune effectors is crucial to maintain immune homeostasis. Linking proteostasis to cell death, this paradigm might prove useful for biotechnological purposes, and the design of novel anti-cancer therapies.