• 한국유체기계학회 논문집
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• 제15권6호
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• pp.31-38
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• 2012

Rotor of rotating machinery is the highly damaged part. Fault of 7 different types was confirmed as the main causes of rotor damage from the pump failure history data in domestic and U.S. nuclear. For each fault types, simulation testing was performed and fault signals were collected form the sensors. To calculate the statistical parameters of time-domain & frequency-domain, measured signals were analyzed by using the discrete wavelet transform, fast fourier transform, statistical analysis. Total 84 parameters were obtained. And Effectiveness factor were used to evaluate the discrimination capacity of each parameter. From the effectiveness factor, RAW-P4/RAW-P7/WT2-NNL/WT2-EE/WT1-P1 showed high ranking. Finally, these parameters were selected as the feature parameters of intelligent fault diagnostics for rotor.

• 대한한의진단학회지
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• 제17권3호
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• pp.275-286
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• 2013

In the present study, antioxidant activity and protective effect of extracts from Sambucus williamsii var. coreana stems (SWC) were evaluated on tert-butyl hydroperoxide (t-BHP) induced oxidative stress in human liver (Chang) cells. Antioxidant activities of the SWC extracts were determined by various radical scavenging activities, such as DPPH, ferric reducing antioxidant power (FRAP), 2,2'-azinobis-(3-ethybenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and oxygen radical absorbance capacity (ORAC) assay. SWC extracts showed strong antioxidant effect on various assay. To determine the hepatoprotective effects of SWC on t-BHP induced oxidative damage, cell viability was measured using MTT assay. Pretreatment of SWC extracts showed increasing cell viability, decreasing ROS and restoring mitochondria membrane potential on t-BHP induced oxidative stress in Chang cells. Our findings suggest that SWC extracts may be considered a potential agent for therapeutic protective effect from oxidative stress through its antioxidant activity.

• 한국방재학회 논문집
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• 제1권2호
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• pp.63-74
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• 2001

본 논문에서는 모의실험을 이용하여 진동감시를 통한 거대 구조물에서의 비파괴 손상탐지의 타당성을 입증하였다. 트러스 형식의 구조물에 대한 비파괴 손상탐지 이론을 정립하였다. 이 이론의 타당성 조사를 위하여 16개의 격간과 246개의 요소로 구성되어 있는 3차원 트러스 구조물을 유한요소로 모델링 하였으며, 이 모델을 이용하여 모의 손상을 가하였다. 손상의 경우는 총 4가지로 대상 구조물의 한 곳에서 손상이 발생한 경우부터 세 곳에서 손상이 발생한 경우까지를 고려하였다. 주어진 모달 매개변수를 이용하여 미세 손상 뿐 아니라 큰 손상에 대해서도 결과가 잘 일치함을 알 수 있었다.

• BMB Reports
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• 제53권4호
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• pp.191-205
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• 2020

The unexpected pandemic set off by the novel coronavirus 2019 (COVID-19) has caused severe panic among people worldwide. COVID-19 has created havoc, and scientists and physicians are urged to test the efficiency and safety of drugs used to treat this disease. In such a pandemic situation, various steps have been taken by the government to control and prevent the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2). This pandemic situation has forced scientists to rework strategies to combat infectious diseases through drugs, treatment, and control measures. COVID-19 treatment requires both limiting viral multiplication and neutralizing tissue damage induced by an inappropriate immune reaction. Currently, various diagnostic kits to test for COVID-19 are available, and repurposing therapeutics for COVID-19 has shown to be clinically effective. As the global demand for diagnostics and therapeutics continues to rise, it is essential to rapidly develop various algorithms to successfully identify and contain the virus. This review discusses the updates on specimens/samples, recent efficient diagnostics, and therapeutic approaches to control the disease and repurposed drugs mainly focusing on chloroquine/hydroxychloroquine and convalescent plasma (CP). More research is required for further understanding of the influence of diagnostics and therapeutic approaches to develop vaccines and drugs for COVID-19.

• 대한예방한의학회지
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• 제10권1호
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• pp.141-153
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• 2006

In order to study the changes in hematology and serum chemistry of rats injected with glycerol, Sprague-Dawley albino rats weighing 240 to 260 gm were injected intramuscularly with a 50% solution of glycerol(8ml/kg). We measured the values of hematology and serum chemistry, and compared the measured values of S1 group(passed for 1day after injection of glycerol), S2 group(passed for 2days after injection of glycerol), S3 group(passed for 3days after injection of glycerol), S4 group(passed for 3days after injection of glycerol) and S5 group(passed for 4days after injection of glycerol) with those of Normal group(non-treated group). The results are summarized as follows : 1. In body temperature, S1, S2, S4 groups showed significantly higher compared with Normal group, especially S2 group was higher than S1 group(p<0.05). But S5 group was lower than Normal group(p<0.05). 2. In RBC, S1 group was lower than Normal group(p<0.05). And in Hct, S1, S2, S3 groups were lower than Normal group(p<0.05), in Hb, S1 and S3 groups were lower than Normal group(p<0.05). 3. In WBC, S1, S2 groups were higher than Normal group(p<0.05). and in WBC differential count, S2, S3, S5 groups were higher than N, S1, S4 groups in monocyte(p<0.05). 4. In GOT, S1 group was higher than Normal group(p<0.05), and S2, S3, S4, S5 groups were lower than S1 group(p<0.05). In GPT, S1 group was higher than Normal group(p<0.05), and S2, S3 groups were lower than S1 group(p<0.05), S4, S5 groups were lower than N, S1, S2, S3 groups(p<0.05). 5. In total cholesterol and creatinine, S4 group was higher than Normal group(p<0.05). According to the above experimental results, we could find the anemia, inflamation, damage of renal function for 4 days by intramuscularly injection with a 50% solution of glycerol(8ml/kg) in rat.

• Composites Research
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• 제13권1호
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• pp.40-49
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• 2000

저속 충격과 같은 충격 하중은 복합재 구조물에 중요한 손상의 요인이 되며, 충격에 의해 발생한 층간분리와 같은 손상은 쉽게 검출하기 힘들며 구조물의 큰 위험 요인이 될 수 있다. 본 연구에서 이러한 충격 하중을 계속적으로 감시할 수 있는 스마트 복합재 구조물의 충격 모니터링 시스템 개발의 기초 연구를 수행하였다. 충격 모니터링이란 충격이 발생하였을 때 충격 하중이 발생한 위치를 검출하고, 충격에 의하여 구조물에 손상이 발생하였는지 판단하고, 발생하였다면 어느 정도의 손상인지를 평가할 수 있는 시스템을 말한다. 본 연구에서는 이 시스템의 첫 단계인 복합적층 평판에 대한 충격 위치 검출 연구에 이어서 두 번째 단계로 충격 손상의 발생 여부를 실시간으로 검사할 수 있는 방법을 연구하였다. 본 연구에서는 충격에 의한 PZT 신호를 시간-주파수 해석 방법인 웨이블릿 변환을 이용하여 손상 모니터링 하는 연구를 수행하였다.

• Smart Structures and Systems
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• 제5권4호
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• pp.469-482
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• 2009

The emerging sensor-based structural health monitoring (SHM) technology has a potential for cost-effective maintenance of aging civil infrastructure systems. The author proposes to integrate continuous and global monitoring using on-structure sensors with targeted local non-destructive evaluation (NDE). Significant technical challenges arise, however, from the lack of cost-effective sensors for monitoring spatially large structures, as well as reliable methods for interpreting sensor data into structural health conditions. This paper reviews recent efforts and advances made in addressing these challenges, with example sensor hardware and health monitoring software developed in the author's research center. The hardware includes a novel fiber optic accelerometer, a vision-based displacement sensor, a distributed strain sensor, and a microwave imaging NDE device. The health monitoring software includes a number of system identification methods such as the neural networks, extended Kalman filter, and nonlinear damping identificaiton based on structural dynamic response measurement. These methods have been experimentally validated through seismic shaking table tests of a realistic bridge model and tested in a number of instrumented bridges and buildings.

• 한국의사학회지
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• 제27권1호
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• pp.87-112
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• 2014

Purpose : "The Part of Cold damage in Uihakipmun" is the collection of the books on Cold damage which follow the way of description focusing on symptoms before Ming dynasty. "The chapter of First symptom" in this part is the first chapter which described focusing on the symptoms in earnest. This research is to discover the reference books of "The chapter of First symptom" in detail. Methods : I compared the books presented in the reference list of "The Part of Cold damage in Uihakipmun" with the sentences of "The chapter of First symptom". Results & Conclusions : "The chapter of First symptom" referred to "Sanghanyukseo(傷寒六書)" and "Injaesanghanryuseo(仁齋傷寒類書)" mainly, and the rest were supplemented with other books like "Hwalinseo(活人書)". And the books which were not listed on the reference like "Sanghanmyeongriron(傷寒明理論)", "Yupyeonhwalinseogwaljijangdoron(類編活人書括指掌圖論)" were also referred in part. Among the reference list of "The Part of Cold damage in Uihakipmun", "Baekmun(百問)" doesn't indicate "Sanghanbaekmun(傷寒百問)" but "Sanghanbaekmunga(傷寒百問歌)". As for the history of the books on cold damage which described focusing on symptoms, "Injaesanghanryuseo" added new contents on the basis of "Hwalinseo" and after that, it had a large influence on "Sanghanyukseo" and "The Part of Cold damage in Uihakipmun". In case of 33.4% of the chapter of first symptom, the reference books were not found. It includes the part that the reference books were not found and also the part that Lee Cheon added his personal opinion. For this parts, the in-depth study is needed afterwards.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.757-781
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• 2016

The results of diagnostics and analysis of an industrial hall located on the premises of a thermal power plant severely damaged by fire are presented in the paper. The comprehensive failure-related diagnostics, non-destructive and destructive tests of steel and concrete materials, geodetic surveying of selected structural members, numerical modelling, static analysis and reliability assessment were focused on two basic goals: The determination of the current technical condition of the load bearing structure and the assessment of its post fire resistance as well as assessing the degree of damage and subsequent design of reconstruction measures and arrangements which would enable the safe and reliable use of the building. The current mechanical properties of the steel material obtained from the tests and measured geometric characteristics of the structural members with imperfections were employed in finite element models to study the post-fire behaviour of the structure. In order to compare the behaviour of the numerically modelled steel roof truss, subjected to the effects of fire, with the real post-fire response of the damaged structure theoretically obtained resistance, critical temperature and the time at which the structure no longer meets the required reliability criteria under its given loading are compared with real values. A very good agreement between the simulated results and real characteristics of the structure after the fire was observed.

• Composites Research
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• 제28권4호
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• pp.148-154
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• 2015

구조건전성 모니터링은 구조물에 발생된 손상을 조기에 감지 및 적절한 유지보수를 통해 재정적 혹은 인명 피해를 방지하기 위해 실시된다. 대부분의 능동센싱 기반 구조건전성 모니터링에서는 많은 수의 압전체(piezoelectric transducer) 센서와 구동기(actuator)를 필요로 한다. 구조건전성 모니터링 시 사용된 압전센서에 결합이 존재하는 경우, 구조물의 상태진단에 문제가 발생할 수 있다. 본 연구에서는 신뢰성 있는 구조건전성 모니터링 결과를 위해 임피던스 기반 센서 자가 진단법을 사용하여 다수 센서의 결함을 탐지하였다. 또한 사용된 접착제와 센서의 정보가 충분치 못한 경우, 사용된 센서로부터 측정된 데이터만을 토대로 센서결함 진단을 위한 알고리즘을 소개하였다. 알고리즘이 적용 가능한 온도 범위를 실험적으로 분석함으로써 개발된 기법이 실제 환경에서 응용이 가능함을 확인하였다.