• 생명과학회지
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• 제19권11호
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• pp.1623-1628
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• 2009

본 연구는 지구성 운동 시 복합 기능성보조제 투여가 운동 수행력과 에너지기질인 글루코스(Glucose), 유리지방산(FFA)동원과 중추 피로물질인 암모니아(Ammonia), 5-HT, 말초피로요소인 젖산(Lactate), 무기인산(Phosphorus), pH에 어떠한 영향을 미치는지를 비교분석함으로써, 복합 기능성보조제 투여가 운동수행에 미치는 효과를 규명하는데 그 목적이 있었으며 연구 결과 다음과 같은 결론을 얻었다. 1. 지구성 운동수행시간은 투여 전과 비교하여 투여 후에 10.7% 증가하였으며 통계적으로 유의한 차이를 보였다(p<0.05). 2. 혈중 피로물질 농도(Ammonia, Lactate, Phosphorus, pH, 5-HT) 의 변화는 실험의 모든 시기에서 투여 전, 후 간에 통계적으로 유의한 차이가 나타나지 않았다. 3. 혈중 에너지기질 농도(Glucose, FFA) 의 농도 변화는 실험의 모든 시기에서 투여 전, 후 간에서 통계적으로 유의한 차이가 나타나지 않았다. 결론적으로, 복합 기능성보조제 투여는 운동수행력을 10.7% 향상시켰으며, 향상된 운동수행력에도 불구하고 혈중피로물질의 추가적인 축적은 없었다. 따라서, 복합 기능성보조제 투여는 지구성 운동수행 시 피로물질 축적의 지연을 초래함으로써 운동수행력 증진에 긍정적인 영향을 미쳤다. 그러나, 단일 물질 투여에 의한 선행연구와 본 연구 결과를 비교할 때, 복합 투여가 단일투여보다 운동수행력 증진에 효과적이라고 판단하기는 어렵다. 따라서, 운동수행력 증진 측면에서 단일투여와 복합 투여 효과의 차이를 규명하기 위해서는 추후 다양한 피험자를 대상으로 복합투여물질의 구성 물질 및 비율, 다양한 운동의 형태에 대한 지속적인 연구가 필요하다고 사료된다.

• 대한물리의학회지
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• 제16권2호
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• pp.101-113
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• 2021

PURPOSE: The purpose of this study was to investigate the differences and correlation between body composition, exercise performance, and behavior based on playing football in childhood. METHODS: 16 subjects who played football in childhood participated in the study. Body composition and exercise performance were measured, and problem behavior was assessed for each of them. All subjects were asked to play football 50 min/day, one day/week for 8-weeks. RESULTS: Muscle mass, muscular strength, balance, and cardiopulmonary endurance, anxiety depression, atrophy depression, attention problems, rule violations, DSM somatization problems, DSM rebellious behavior problems, and sociality significantly increased after 8-weeks. There was a negative (-) correlation between anxiety depression and atrophy depression, and DSM somatization problem and muscular strength, attention problem and balance, and rule violation and cardiopulmonary endurance, after playing football. CONCLUSION: These results confirmed that playing football in childhood had a positive effect on body composition, and that exercise performance and problem behavior were related.

• Steel and Composite Structures
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• 제11권4호
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• pp.307-324
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• 2011

With the increasing use of concrete-filled steel tubes (CFST) as structural members, there is a growing need to provide suitable measures for possible strengthening or repair of these kinds of structural elements. Fibre reinforced polymer (FRP) jacketing is a recent method and is particularly attractive in which it does not significantly increase the section size, and is relatively easy to install. Thus, it can be used to enhance strength and/or ductility of CFST members. Very little information is available on the performance of FRP-strengthened CFST members under fire conditions. This paper is an attempt to study the fire performance of CFST columns strengthened by FRP. The results of fire endurance tests on FRP-strengthened circular CFST columns are presented. Failure modes of the specimens after exposure to fire, temperatures in the cross section, axial deformation and fire resistance of the composite columns are analysed. It is demonstrated that the required fire endurance can be achieved if the strengthened composite columns are appropriately designed.

• 운동영양학회지
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• 제25권2호
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• pp.15-19
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• 2021

[Purpose] Skeletal muscle glycogen is a determinant of endurance capacity for some athletes. Ginger is well known to possess nutritional effects, such as anti-diabetic effects. We hypothesized that ginger extract (GE) ingestion increases skeletal muscle glycogen by enhancing fat oxidation. Thus, we investigated the effect of GE ingestion on exercise capacity, skeletal muscle glycogen, and certain blood metabolites in exercised rats. [Methods] First, we evaluated the influence of GE ingestion on body weight and elevation of exercise performance in rats fed with different volumes of GE. Next, we measured the skeletal muscle glycogen content and free fatty acid (FFA) levels in GE-fed rats. Finally, we demonstrated that GE ingestion contributes to endurance capacity during intermittent exercise to exhaustion. [Results] We confirmed that GE ingestion increased exercise performance (p<0.05) and elevated the skeletal muscle glycogen content compared to the nonGE-fed (CE, control exercise) group before exercise (Soleus: p<0.01, Plantaris: p<0.01, Gastrocnemius: p<0.05). Blood FFA levels in the GE group were significantly higher than those in the CE group after exercise (p<0.05). Moreover, we demonstrated that exercise capacity was maintained in the CE group during intermittent exercise (p<0.05). [Conclusion] These findings indicate that GE ingestion increases skeletal muscle glycogen content and exercise performance through the upregulation of fat oxidation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.19-22
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• 2007

This study discussed the prevention of the spalling and improvement of the fire resistance performance how to fill up lightweight foamed concrete on high strength RC column attached with the stone panel. The destructive spalling extremely occur caused by sudden high temperature and increased vapor pressure corresponding to falling the ston panel at all RC column, and the steel bar is exposed. The stone panel fall off about 30 minutes and spalling occur about 70 minutes on Plan RC column, fire endurance paint, and fire endurance mortar, so it can be confirmed that fire endurance paint and mortar, which is used as fire endurance material, are not effective. In the other side, it can be protected from fire about $120{\sim}140$ minutes when the lightweight foamed concrete is used as fire endurance material. For the weight loss after the fire test, plain is 33, fire endurance paint is 37%, and fire endurance mortar s 40.7%. And W/B 60%-3 is 53.4%, 60%-1.5 is 40.1%,65%-3 is 39.4%, and 65%-1.5% is 47.1. Overall, the weight loss of the plain is lower than that of the lightweight foamed concrete.

• 한국항공우주학회지
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• 제44권6호
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• pp.520-529
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• 2016

본 연구의 목적은 중고도-장기체공 무인기의 성능을 역설계를 통해 분석하는 것이며, 역설계를 위한 모델로 RQ-1 Predator를 선정하였다. CATIA 프로그램을 사용하여 RQ-1 Predator의 외형에 대한 형상과 중량 분포를 생성하였다. RQ-1 Predator의 공력특성은 주로 와류격자법과 경험식을 조합하여 수행하였으며, 추진 성능은 Howe의 경험식을 통해 수행되었다. 상승률, 실용상승한도, 항속 거리, 그리고 체공 시간에 대한 역설계를 수행하였으며, 역설계 결과가 참고문헌과 잘 일치함을 확인하였다.

• 대한임베디드공학회논문지
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• 제14권2호
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• pp.79-86
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• 2019

For decades, in-memory data structures have been designed for DRAM-based main memory that provides symmetric read/write performances and has no limited write endurance. However, such data structures provide sub-optimal performance for NVM as it has different characteristics to DRAM. With this motivation, we rethink a conventional red-black tree in terms of its efficacy under NVM settings. The original red-black tree constantly rebalances sub-trees so as to export fast access time over dataset, but it inevitably increases the write traffic, adversely affecting the performance for NVM with a long write latency and limited endurance. To resolve this problem, we present a variant of the red-black tree called a hierarchical balanced binary search tree. The proposed structure maintains multiple keys in a single node so as to amortize the rebalancing cost. The performance study reveals that the proposed hierarchical binary search tree effectively reduces the write traffic by effectively reaping the high capacity of NVM.

• 생명과학회지
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• 제27권3호
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• pp.361-369
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• 2017

미토콘드리아의 항상성은 미토콘드리아 생합성과 마이토파지(자가포식에 의한 미토콘드리아 분해)로 불리는 2가지 주요 과정들에 의해 정교하게 조절되고 있다. 지구성 운동 훈련에 반응하여 골격근에서 미토콘드리아 생합성에 관한 기전들은 잘 정립되어 있는 반면 지구성 운동 훈련 후 골격근의 마이토파지 조절 기전과 마이토파지와 미토콘드리아 생합성의 협응을 조절하는 기전은 아직 명확히 밝혀져 있지 않다. 최근 연구들에 의하면 지구성 운동 훈련은 골격근에서 미토콘드리아 생합성, 미토콘드리아 역동성, 미토콘드리아 분해와 관련된 유전인자들의 발현을 증가시킨다고 하였다. 하지만 골격근에서 자가포식이 억제되었을 경우, 지구성 운동 훈련에 의한 미토콘드리아 생합성과 관련된 지표들인 Cox IV와 citrate synthase의 증가는 상쇄되었다. 따라서 자가포식과 마이토파지는 골격근의 미토콘드리아 생합성에 중요한 역할을 하며 정반대되는 이 두 과정(이화 또는 동화작용)의 협응 과정이 지구성 운동 훈련에 반응하여 대사적 기능과 지구력 운동 수행능력을 향상시키는 것과 같은 골격근의 적응에 중요한 듯하다. 지구성 운동은 미토콘드리아의 일정한 숫자를 유지시키기 위해 미토콘드리아 생합성, 미토콘드리아의 융합과 분열, 자가포식/마이토 파지들의 각각의 과정들을 조절하는 것으로 여겨진다. 지구성 운동 훈련은 골격근에서 마이토파지를 활성화시켜 미토콘드리아 양과 질을 조절하여 늙고 건강하지 않은 미토콘드리아를 젊고 건강한 미토콘드리아로 교체시킬 수 있다. 이 총론에서 미토콘드리아 생합성과 마이토파지의 분자학적 기전과 서로 상반되는 이 두 과정간의 협응이 골격근의 지구성 훈련에 대한 세포적 적응에 관련한다는 내용이 논의될 것이다.

• Tribology and Lubricants
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• 제32권5호
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• pp.154-159
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• 2016

This paper presents an experimental study of the leakage performance and endurance performance of a mechanical face seal in the 7-ton-class turbopump of the Korea Space Launch Vehicle 2 third-stage engine. We install a mechanical face seal between the fuel pump and turbine to prevent the mixing of the fuel and turbine gas. We design and manufacture a prototype mechanical face seal, which has two parts, namely, a bellows seal assembly and mating ring. We set up a test facility to measure the leakage and endurance of the mechanical face seal. For the similarity tests, we use water under real operating conditions such as high rotational speed, high temperature, and high pressure. Through investigation of the leakage and carbon wear rate, it is possible to evaluate the performance of the mechanical face seal. The results of the leakage and endurance performance test demonstrate the absence of any leakage from the prototype mechanical face seal after a trial run and clarify that the acceptable wear rate fully satisfies the turbopump requirements. Finally, we install a qualified mechanical face seal in a 7-ton-class turbopump and perform a validation test in the turbopump real-propellant test facility in the Korea Aerospace Research Institute. The test results confirm that the mechanical face seal works well under real operating conditions.

• 대한통합의학회지
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• 제11권4호
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• pp.95-104
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• 2023

Purpose : This study aimed to introduce a 12-week muscular endurance exercise program and β-glucan consumption to obese elderly people with sarcopenia. We evaluated the program's impact on appendicular skeletal muscle strength and function, muscle function-related physical strength, blood lipids, and IGF-1. The results will serve as foundational data for preventing and improving sarcopenia. Methods : Forty elderly people aged 65 or older were recruited and underwent dual-energy X-ray absorptiometry. Based on criteria related to appendicular skeletal muscle mass (ASM/Height2: less than 5.4 kg/m2) and body fat percentage (at least 30% for women and 25% for men), we selected 24 obese elderly people with sarcopenia and excluded 56 who did not meet the criteria. Variables related to sarcopenia, blood lipids, IGF-1, and muscle function were measured before the 12-week muscular endurance exercise program. Results : In sarcopenic obese elderly participants, the 12-week muscular endurance exercise program significantly increased bone density and muscle mass while decreasing fat mass and percentage (p<.05). This program also improved grip strength, static balance, and SPPB in sarcopenic obese older adults. Furthermore, their 6-minute walk distance significantly increased (p<.05). Conclusion : Muscular endurance exercises combined with supplement intake can increase appendicular skeletal muscle and improve muscle strength and function, thereby improving the daily physical performance of the elderly.