• 수산해양기술연구
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• 제17권2호
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• pp.93-103
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• 1981

Si-Cr계 내열강 SUH3와 Cr-Ni계 stainless강 SUS 303 및 이들이 마찰용접재 SUH3-SUS303을 $1,060^{\circ}C$에서 용체화처리하고 다시 $700^{\circ}C$에서 10, 100시간 시효열처리한 각 시험편의 고온 피로강도에 대한 시효열처리의 효과를 알기 위하여 $700^{\circ}C$에서 고온 회전굽힘 피로시험을 하고 파약거동을 미시적으로 관찰하여 다음과 같은 결과를 얻었다. 1) SUH3재와 SUS303재의 최적마찰용접조건은 회전수 2420rpm, 마찰가압력 $8kg/mm^2$, 전 upset량 7mm(마찰가압시간 3sec, upset시간 2sec)이었다. 2) $700^{\circ}C$ 고온에서 장시간 이루어지는 고온피로시험에 있어, 용체화처리재의 S-N 곡선 경사부의 기울기가 가장 급하게 나타났다. 3) SUH3-SUS303 마찰용접재는 $1,060^{\circ}C$에서 1시간용체화 처리하고, $700^{\circ}C$에서 시효처리하는 경우 최적시효시간은 10시간이었다. 4) 10시간 시료재의 고온피로한도는 모재보다 SUH3은 75.4%, SUS303은 28.5% 높았으며, 용접재 SUH3-SUS303은 44.2% 정도 높았다. 100시간 시효재는 모재보다 SUH3은 64.91% SUS303은 30.4% 높았으며, SUH3-SUS303은 30.4% 높았으며, SUH3-SUS303은 36.6% 높았다. 5) 마찰용접재의 상온 및 고온의 피로파단은 모두 SUS303의 모재측에 발생하였으며, 용접면에서의 파단은 전혀 없었다. 6) SUS303재와 마찰용접재 SUH3-SUS303재의 크랙은 입내파양형이었으나 SUH3은 입계크랙의 전파로 파양한다.

• 열병합발전
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• 통권50호
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• pp.18-22
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• 2006

The tilting pad journal bearing has widely used to support high pressure/high rotating turbine rotors owing to their inherent dynamic stability characteristics. However, fatigue damages in the upper unlcaded pads and the break of locking pins etc. by pad spragging were continuously taken place in the actual steam turbines. The purpose of this paper is to develope a new bearing model that can prevent bearing damage problem effectively by pad spragging in a tilting pad journal bearing. A new bearing model which has a wedged groove is suggested from the studies of spragging mechanism performed by previously research works. The spragging characteristics of the upper unloaded pad are studied experimentally in order to verify the reliability of a new bearing model. It can be known that the phenomenon of pad spragging nearly does not occur in the new bearing model under the various experimental conditions. And it is observed that any kinds of bearing failures by pad spragging does not detect in the application of actual steam turbines.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1460-1463
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• 2010

Railway has been pointed to the efficiency of transportation, rapid transit, and comfortable train ride. the construction of railway near the downtown area and station building are increasing for maximization of utilization and convenience. but the heavy of transportation and rapid transit lead to increase noise and vibration. The noise and vibration of railway may cause the civil appeal, decline in the serviceability and insufficiency of environmental standard. In this study, floating slab vibration and repeated connection of devices to support joints and fatigue stress analysis of punching shear performance review was conducted to evaluate the safety.

• 대한본초학회지
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• 제22권2호
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• pp.51-63
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• 2007

Objectives : For the congenital feeble, the Gongjindan is useful medicine. The experiment is to estimate the value of the Gongjindan as therapeutic agent preventing against aging with an analysis of the ingredients and the bio-activating effects by enzymologic methods. Methods : General ingredients' of the Gongjindan's extract were analyzed first and the quantitative analysis of a reducing sugar, a soluble protein, an amino acid and minerals was made. The Gongjindan, which is extracted, concentrated, and freeze drying with water, ethanol and chloroform, have got applied for the experiment. The effects on electronic donating ability, SOD-like activity, nitric oxide inhibition, xanthine oxidase inhibition, whitening effect have been investigated in the physiological activity measurement of function experiment. Results : The contained amino acid, in order of high amount, is Arginine, Alanine, Glutamic acid, Proline and the contained free amino acid is Glutamic acid, Leucine, Lysine, Phenylalanine. The derivative of free amino acid is ${\gamma}-Aminoisobutyric$ acid, Phosphoserine, Taurine. And the Gongjindan is containing 13 species of minerals in order of Ca>K>Na>Mg>Fe>AI>Mn. Then, to assure of the Gongjindan's capability of anti-oxidation, these following subjects-polyphenol, electronic donating ability, SOD-like activity, nitric oxide inhibition, xanthine oxidase inhibition, tyrosinase inhibition- are analyzed and show high activity especially the most in ethanol extracts. Conclusion : With this analysis of ingredients, the Gongjindan is containing many materials functioning as anti-oxidation, anti-aging, anti-fatigue, neurotransmitter and immune agent. Moreover, In every water, ethanol, chloroform extracts, the Gongjindan's capability of anti-oxidation is confirmed so that we can apply to patients' treatment clinically.

• 한국식품저장유통학회지
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• 제22권4호
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• pp.598-606
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• 2015

전복 음료를 개발하기 위하여 전복에 식물류를 혼합한 전복 복합물의 in vitro 항산화능을 측정하였으며, 정상군, 대조군, 전복 복합물의 성인 1일 1회분(APM-1) 급이군(EAPM-1) 및 3회분(APM-2) 급이군(EAPM-2)으로 구분하여 4주간 실험사육하였다. 전복 복합물의in vitro 항산화능과 총 페놀 및 플라보노이드 함량은 APM-2가 유의적으로 높았다. 혈중 총 지질 함량은 대조군에 비해 운동과 전복복합물을 병행급이한 EAPM-2군이 유의적으로 감소되었다. LDH 활성 및 BUN 함량은 대조군에 비해 전복 복합물 급이군에서 유의적으로 감소되었다. AST 활성은 전복 복합물 급이 시 대조군과 유의차가 없었으며, ALT 및 ALP 활성은 대조군에 비해 유의적으로 감소되었다. 혈청 및 간 조직에서 지질과산화물 함량은 대조군에 비해 전복 복합물 급이 군에서 유의적으로 감소하였다. 간 조직의 라디칼 소거능은 대조군에 비해 전복 복합물의 급이 시 유의적으로 증가하였다. 따라서 전복 복합물은 항산화능 및 페놀 화합물에 의존하여 트레드밀 운동에 의한 산화적 스트레스 해소 및 피로 회복 에 도움이 될 것으로 예상된다.

• 한국해양공학회지
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• 제3권2호
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• pp.138-144
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• 1989

It has been very important in various industry fields to improve the fatigue strength characteristics of bearings such as bearing life, fatigue limit, etc., because such poor properties could result in shortening the machinery life as well as in decreasing the accuracy. However, no successful heat treatment criterion seems to be available at present. In this study, the effect of the $170^{\circ}C\times120min$ tempering cycles repeated after $380^{\circ}C\times80min$ oil quenching for $800^{\circ}C$ spheroidizing-annealed bearing steel (STB2) as base metal on the $120^{\circ}C$ high temperature rotary bending fatigue strength characteristics were investigated, including the effects on hardness, Charpy impact value and micro-structure, in order to seek for the best heat treatment condition finally. The important results obtained are as follows : 1) The optimal cycle of tempering so that the fatigue strength .sigma. could become the highest was the 4th cycle. And it is confirmed that this $\sigma_{F}$ is about 6 times more increased than that of base metal, and about 1.3 times more increased than the case of the 1 cycle tempered. 2) As a result of the investigation for the effects of tempering cycles on hardness, the hardness at the tempering number of 2 thru 5 cyles was not decreased severely ; only about 10% decrease from those of the quenched and 1 cycle tempered case. Such hardness is equivalent to $H_{R}$/C61-62 with no bad effect on anti-abrasion of bearing steel. 3) In the case of 2 thru 5 cycle tempering as well as 1 cycle tempering, the impact value was not so improved comparing with the case of quenching, but an increase of 5 to 10% could be expected at least. 4) It was experimentally confirmed that the control of the mechanical properties improvement such as fatigue strength and fatigue life for bearing steels could be possible by the number of tempering cycles.

• 한국해양공학회지
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• 제3권2호
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• pp.638-638
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• 1989

It has been very important in various industry fields to improve the fatigue strength characteristics of bearings such as bearing life, fatigue limit, etc., because such poor properties could result in shortening the machinery life as well as in decreasing the accuracy. However, no successful heat treatment criterion seems to be available at present. In this study, the effect of the $170^{\circ}C\times120min$ tempering cycles repeated after $380^{\circ}C\times80min$ oil quenching for $800^{\circ}C$ spheroidizing-annealed bearing steel (STB2) as base metal on the $120^{\circ}C$ high temperature rotary bending fatigue strength characteristics were investigated, including the effects on hardness, Charpy impact value and micro-structure, in order to seek for the best heat treatment condition finally. The important results obtained are as follows : 1) The optimal cycle of tempering so that the fatigue strength .sigma. could become the highest was the 4th cycle. And it is confirmed that this $\sigma_{F}$ is about 6 times more increased than that of base metal, and about 1.3 times more increased than the case of the 1 cycle tempered. 2) As a result of the investigation for the effects of tempering cycles on hardness, the hardness at the tempering number of 2 thru 5 cyles was not decreased severely ; only about 10% decrease from those of the quenched and 1 cycle tempered case. Such hardness is equivalent to $H_{R}$/C61-62 with no bad effect on anti-abrasion of bearing steel. 3) In the case of 2 thru 5 cycle tempering as well as 1 cycle tempering, the impact value was not so improved comparing with the case of quenching, but an increase of 5 to 10% could be expected at least. 4) It was experimentally confirmed that the control of the mechanical properties improvement such as fatigue strength and fatigue life for bearing steels could be possible by the number of tempering cycles.

• 대한한방내과학회지
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• 제29권4호
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• pp.922-938
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• 2008

Objectives : Rhodiola rosea has been used in herbal medicine to treat various conditions, such as antimelancholia, antifatigue, improvement of work competence and prevention of altitude sickness. In this study, we investigated effects of Rhodiola rosea extract (KH101) on fatigue in forced swimming rats. Methods : Sprague-Dawley rats were induced with fatigue by forced swimming, then rats in each group were treated with KH101. We observed changes of glucose, LDH and cortisol in serum and LDH, glycogen, hexokinase, citrate synthase MDH, SDH and CK in muscle. Results : Obtained results were as follows: 1. Continuance times of exercise significantly increased in all groups at day 1, in the 50 mg/kg concentration group at day 2, in all groups at day 3 and in the 50 mg/kg conc. group at day 4. 2. In serum, glucose significantly decreased in all concentration groups. 3. In the soleus muscle, LDH significantly decreased in the 50 mg/kg concentration group. HK significantly decreased in the 100 mg/kg conc. group. SDH significantly increased in the 100 mg/kg conc. MDH were significantly decreased in all conc. groups. 4. In the gastrocnemius muscle, HK significantly decreased in all concentration groups, while MDH significantly increased all conc. groups. Conclusions : It is concluded that the KH101 has and anti-fatigue effect in rats. Additional studies are needed to find the mechanism of the association between each single herb.

• 한국식품과학회지
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• 제49권2호
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• pp.209-214
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• 2017

본 연구에서는 잉여 농산물인 오이를 이용하여 제조한 식초음료의 항피로 효과를 검증하기 위하여 고강도 운동을 실시한 흰쥐에 오이식초음료를 매일 섭취시켜 지구력, 혈청 피로물질, 간과 근육 조직 내 글리코겐 함량, 근육 내 LDH 및 CK 등의 변화를 살펴보았다. 실험동물은 4주령의 수컷 SD계 흰쥐 15마리를 1주간 고형식이로 적응시킨 후 난괴법에 의하여 비운동군(SC), 운동군(EC), 오이식초 섭취군(CV)으로 나누었다(n=5). CV는 사람의 하루 섭취량을 기준으로 체중 kg당 7 mL씩 매일 일정시각에 경구투여 하였고 나머지 그룹은 동량의 증류수를 투여하였다. EC와 CV는 매일 일정한 시각에 트레드밀을 이용하여 분당 15 m로 20분, 분당 20 m로 30분, 분당 25 m로 60분씩 운동을 일주일에 5회 실시하였다. 식이섭취량과 식이효율에서는 그룹 간의 별다른 차이가 나타나지 않았으며 CV군의 신장 무게가 SC군보다 낮았다. 지구력 측정에서 CV가 EC보다 55.96% 더 높은 지구력을 가진 것으로 측정되었고 혈청 피로물질은 CV가 EC보다 현저히 낮은 경향을 보였다. 간과 근육의 글리코겐 함량은 CV가 다른 두 군보다 높은 수치를 나타내어 오이식초음료의 섭취에 따라 간과 근육에서의 글리코겐 재합성이 증가된 것을 확인하였으며 근조직의 LDH와 CK 측정 결과 CV와 EC를 비교하였을 때 CV에서 증가된 수치를 보였다. 이와 같이 고강도 운동으로 훈련을 실시한 흰쥐는 오이식초음료의 섭취에 의해 지구력 증진과 혈중피로물질의 감소, 간과 근육에서의 글리코겐 재합성, ATP 수치의 유지 및 젖산 대사 촉진과 같은 항피로 효과를 나타내었으므로 본 연구의 결과가 오이식초를 이용한 스포츠드링크 개발에 도움이 될 수 있을 것으로 사료된다.

• 한국응용과학기술학회지
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• 제40권4호
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• pp.761-772
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• 2023

본 연구의 목적은 남자 대학 엘리트 조정선수의 2000 m 로잉 에르고미터 수행 후 저온침수 처치를 통해 혈중 젖산, LDH, MDA 및 SOD의 변화에 긍정적인 영향을 주어 피로 회복에 미치는 영향을 구명하는 데 있다. 이에 남자 대학 엘리트 조정선수 10명을 대상으로 고강도 로잉 에르고미터 2,000 m 수행 후 비 처치와 저온 침수 처치의 효과를 비교하였다. 측정 변인들에 대한 결과를 검증하기 위해 처치 및 시기 간 상호작용 효과를 분석하기 위해 ANOVA를 실시하였고 각 항목별 유의수준 .05로 설정하여 다음의 결과를 도출하였다. 젖산은 시기 간 주효과가 나타났고(p<.001) 그룹 내 시기별 차이가 났다(p<.001). 또한, LDH는 그룹 내 시기별 차이가 나타났다(p<.05). MDA는 그룹×시기 간 상호작용 효과가 나타났고(p<.05), 그룹 간(p<.05), 시기 간(p<.001) 주효과가 나타났다. SOD는 그룹 간, 시기 주효과가 나타났고(p<.05) 회복 30분 후 그룹 간 차이가 나타났다(p<.05). 이를 종합해 볼 때, 본 연구에서 실시한 저온침수 처치가 조정 선수의 혈중 피로 물질, 활성산소 및 항산화 효소에 유의한 효과를 나타냈다. 따라서 운동선수의 고강도 훈련 후 저온침수를 적극 활용할 것을 권장한다.