• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.39-43
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• 2010

The main objective of this research is to develop a mechanistic performance predictive model for fatigue cracking of asphalt-aggregate mixtures. Controlled-stress diametral fatigue tests were performed to characterize fatigue cracking of asphalt-aggregate mixtures. Performance prediction model for fatigue cracking was developed using the internal damage ratio (IDR) growth method. In the IDR growth method, the general concepts of the dissipated energy, the reference tensile strain, the threshold tensile strain, and the strain shift factor were introduced. The source of the dissipated energy in the fatigue test is from the intrinsic viscoelastic material property of an asphalt concrete mixture and the damage growth within the asphalt concrete specimen. In controlled-stress mode test, the dissipated energy is gradually increased with an increasing number of load applications.

• 보존과학연구
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• s.21
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• pp.145-175
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• 2000

To examine the method for preservation of papers, 9 kinds of papers were purchased and pretreated for 6 months with various artificial conditions which were controlled as 3 temperature classes($20^{\circ}C$, $80^{\circ}C$, $-20^{\circ}C$&$20^{\circ}C$) and 4 humidity classes(40%, 60%, 80%, 100%).Whiteness, acidity and folding endurance were measured to examine the state of papers pretreated under each condition. From the resultexamining the state, all the papers were best condition at low temperature($20^{\circ}C$) and low humidity(40%) and damaged at high temperature($80^{\circ}C$) and high humidity(100%).The values of whiteness, acidity, and folding endurance were measure din relation with deterioration of papers. According to damage of papers caused by the chemical agent, papers became to be acidic, increased color difference and reduced the force of folding endurance. The effect of change of temperature($-20^{\circ}C$&$20^{\circ}C$) on degradation of papers was not well acquired. Because the period of investigation was not long enough to acquire the data. So the more studies are needed to find the cause of damage of papers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.345-349
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• 2007

In this study a fuzzy trend monitoring method for detecting the engine mechanical faults was proposed through analyzing performance trends of measurement data. The trend monitoring is an engine conditioning method which can find engine faults by monitoring important measuring parameters such as fuel flow, exhaust gas temperatures, rotational speeds, vibration. etc. Using engine condition data set as a input which generated by linear regression analysis of real engine instrument data, an application of fuzzy logic in diagnostics estimate a cause of fault in each components.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.91-95
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• 2012

본 연구에서는 열충격 시험을 통하여 Cell레벨에서의 효율저하 특성을 분석하였다. 열충격 시험은 PV모듈의 시험 규격인 KS C IEC-61215를 이용하여 보다 가혹한 조건인 $-40^{\circ}C$에서 $120^{\circ}C$의 조건으로 500사이클 수행하였다. I-V 측정을 통하여 효율을 분석한 결과, 열충격 시험 전 13.9%에서 열충격 시험 후 11.0%로 효율이 저하 됐으며, 감소율은 20.9% 나타났다.EL촬영을 통해 표면을 분석한 결과 Ribbon접합부 및 Gridfinger의 손상으로 확인 됐으며, 보다 정확한 효율 저하의 원인을 분석하기 위해 단면분석을 실시한 결과 표면손상으로 확인 되었던 위치의 Cell내부에서도 Crack을 확인 할 수 있었다. 또한 FF값을 분석한 결과 열충격 시험 전 72.3%에서 시험 후 62.0%로 11.8%의 감소율을 보였다. 따라서, 경년 시 나타나는 효율저하는 Cell자체의 소모전력 증가와 외부환경에 의한 표면 손상 및 Cell내부의 Crack에 기인하여 가속된다고 판단된다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.11
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• pp.1025-1032
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• 2010

Gas turbine compressor blades used in a combined cycle power plant are possibly damaged and fractured during their operation. There are two possible causes of the failure of compressor blades; one is a defect of material quality which can be detected through some microscopic inspections for the fracture section, the other is high cycle fatigue problem caused by vibration and can be diagnosed by carrying out dynamic characteristics analysis for the blades. In this paper, in order to determine the cause of the failure of compressor blades in a combined cycle power plant, examination of the fracture section and the propagation mechanism of the crack via stress analysis are performed. Dynamic characteristics analysis via FRF estimation is also performed to identify the cause of failure.

• The Korean Journal of Food And Nutrition
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• v.12 no.6
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• pp.592-596
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• 1999

본 연구는 피부미용전공과 비전공여대생의 모발영양지식을 파악하고 모발영양에 관한 과목을 수강한 학생들과 수강하지 않은 대상자들간의 모발상태 모발행동 등을 연구하고자 청주에 있는 피부미용과 여대생 146명과 비전공여대생 145명을 선정하여 설문지를 통해 분석하였다. 본 연구에서 얻어진 결과는 다음과 같다. 모발영양지식은 전공여대생이 비전공여대생에 비해 훨씬 높았고 모발의 진단을 받아본 경험도 전공대상자가 높았다 그러나 모발상태 손상원인 모발에 관한 걱\ulcorner은 두 그룹 모두 비슷한 양상을 보였다. 모발관리도 전공대상자가 비전공대상자 보다 많이 하고 있었고 모발손질 횟수도 전공대상자가 높은 비율로 나타났다 미용실 출입횟수는 2-3달에 한번이 가장높았고 그룹간에 차이는 없었다. 1회 머리손질 비용도 전공대상자가 비전공대상자에 비해 높은 경향이었고 샴푸의 선택기준은 두 그룹 모두 샴푸의 질과 본인 모발의 상태를 우선적으로 고려하여 선택하였다. 결론적으로 피부미용전공여대생은 모발영양과 모발 관리학 등에 관한 수업을 받았기 때문에 모발영양 지식이 많이 모발행동이 더 바람직하였고 모발상태를 양호하게 유지하였다 그러므로 모발에 관한 교육 건강한 모발을 유지하는데 기여한 것으로 나타나 적절한 모발교육 프로그램을 개발하여 비전공여대생들에게도 모발교육을 실시하는 것이 바람직하다고 사료된다.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.2
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• pp.163-166
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• 2002

Introduction: It is frequently occur in sports injury of clavicular fractures in Hapkido players. Weevaluated Hapkido related clavicular fractures and preventive measure. Methods: We experienced 12 cases of Hapkido related clavicle fracture. The age ranged from 13 to18-years-old. All cases were treated by conservative managements. We examined the relationship between the clavicle fractures and Hapkido related pathomechanics.Results: All cases were injured during the practice for the falling-technique. Results were evaluatedby Weitzman and all cases were revealed more than good. Conclusions: In most cases, the correction of the wrong way of falling-technique will reduce theclavicle fractures in the Hapkido players.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.243-248
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• 1992

In order to examine the viability depending on rehydration process and membrane injury of Nocardia mediterranei upon lyophilization, We labeled $3^H$-thymidine in deoxyribonucleic acid of N. mediterrranei to obtain information on the mechanisms of injury caused by lyophilization. Suspensions of rehydrated cells were incubated with added DNase in a buffer solution. Extracellular radioactivity levels appeared to be high in the rehydrated solutions after lyophilization than freezing-thawing. Thus, the membrane systems were injured by lyophilization, but not ovenvhelmed. These considerations were confirmed by electron microscopy. In effects of rehydration, the cell membrane was seriously damaged by strong atmospheric pressure as soon as the inner ampule was opened, but this was not the case without admitting air under vacuum. N. rnediterranei cells, with no additives, were lyophilized and reconstituted without admitting air, virtually about 84% of the cells were viable.

• Journal of the Korean Society of Radiology
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• v.81 no.4
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• pp.806-831
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• 2020

Musculoskeletal injury is the most common cause of children visiting the department of emergency medicine. Since the bone is still developing, pediatric patients have characteristic radiological manifestations, including plastic deformation, greenstick fractures, and buckle (or torus) fractures. Furthermore, growth arrest can occur in those with physeal fractures. Various mechanisms are responsible for pediatric musculoskeletal injury since children have different ranges of activities, depending on their age, such as birth injury and fall and traffic accidents. Some fractures have characteristic locations and radiological manifestations. In this review, we will discuss various radiological manifestations of fractures involving both upper and lower limbs in pediatric patients.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.85-92
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• 2007

In 1980s, a number of bridges with bare concrete deck were constructed on the Korea highway. After 20 years service, many bare concrete decks are still in good condition without special maintenance activity. Therefore, the application of the bare concrete deck is being reestimated from the view of construction and maintenance. As a part of the program, the characteristic of penetration(surface chloride and apparent diffusion coefficient) of de-icing salt into bare concrete bridge deck was analyzed in order to predict the service life of bridge on Korea highway.