• Journal of Mechanical Science and Technology
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• 제16권12호
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• pp.1604-1612
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• 2002

Rollers in the continuous process systems are ones of key components that determine the quality of web products. The condition of rollers (e.g. eccentricity, runout) should be consistently monitored in order to maintain the process conditions (e.g. tension, edge position) within a required specification. In this paper, a new diagnosis algorithm is suggested to detect the defective rollers based on the frequency analysis of web tension signals. The kernel of this technique is to use the characteristic features (RMS, Peak value, Power spectral density) of tension signals which allow the identification of the faulty rollers and the diagnosis of the degree of fault in the rollers. The characteristic features could be used to train an artificial neural network which could classify roller conditions into three groups (normal, warning, and faulty conditions) The simulation and experimental results showed that the suggested diagnosis algorithm can be successfully used to identify the defective rollers as well as to diagnose the degree of the defect of those rollers.

• 전기학회논문지
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• 제64권12호
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• pp.1789-1795
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• 2015

The pulley-type tensioning device subjected to a maximum tension of 34 kN has been developed for 400 km/h high-speed railway. The tensioning device is to maintain the tension variation within 3% of the normal value, irregardless of temperature changes. Field tests shows that the tensioning device had a variation of tension which was as small as 0.6% as temperatures changed from $-5{\sim}7^{\circ}C$. Along with the tensions, we measured its X and Y movements due to the temperature changes. Based on a combination of its X and Y movements, we proposed a new performance index with which we can see if the tensioning device has troubles in operation without tension measurements.

• 대한기계학회논문집
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• 제12권3호
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• pp.457-465
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• 1988

본 연구에서는 벨트 연삭시 즉 집중하중을 받는 평벨트 구동에서 벨트와 풀리 사이의 내접촉 특성을 구하고자 하였다.준 정적평형(quasi-static equilibrium) 상 태에서 벨트구동계의 이론적 해석을 하여 집중하중점을 포함한 벨트-풀리 전접촉구간 에서 벨트장력분포를 구하고 이 결과를 실험치와 비교하였다. 본 연구에서는 집중하 중점 보다는, 집중하중의 벨트-풀리 전접촉구간에 대한 영향을 밝히는데 주안점을 두 었다.

• Journal of Chest Surgery
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• 제7권1호
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• pp.1-8
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• 1974

Acute pulmonary edema was induced by intravenous injection of epinephrine, intravenous infusion of dextran and intratracheal instillation of acid solution index was determined from pressure volume curves in excised lungs. Surface activity was also investigated with measurements of maximum and minimum surface tension and stability index on saline extracts of same lungs. The results were as follows. 1. The expansion index of excised lung in which pulmonary edema was induced by intravenous injection of epinephrine, intravenous infusion of dextran and intratracheal instillation of acid solution was ignificantly decreased as compared with the normal control of $0.86{\pm}0.017$ to $0.74{\pm}0.03$, $0.71{\pm}0.081$and $0.76{\pm}0.02$, respectively. 2. The deflation curves of excised lungs in which pulmonary edema was induced were significantly decreased as compared with the normal controls. 3. The minimum surface tension of excised lung in which pulmonary edema was induced was significantly increased in each groups and stability index was significantly decreased as compared with the normal controls 0.78 to $0.35{\pm}0.039$, $0.29{\pm}0.02 $ and $0.31{\pm}0.083$, respectively. 4. The decrease of pulmonary surface activity in acute pulmonary edema was in proportion to the degree of pulmonary edema regardless of their etiology.

• 한국임상수의학회지
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• 제19권2호
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• pp.199-203
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• 2002

Cardiovascular effects of propofol, were assessed after premedication with xylazine(1.0 mUkg, IM) under oxygen supply(200 ml/kg/min) via a endotracheal tube. Twelve adult mixed-breed dogs were divided into four groups; 0.2(Group 1), 0.4(Group 2), 0.6(Group 3) and 0.8 mg/kg/min(Group 4) of propofol respectively. Arterial blood pressure and electrocardiogram were monitored with a physiograph after an arterial catheter was inserted into the femoral artery. pH, arterial carbon dioxide tension($PaCO_2$and arterial oxygen tension($PaO_2$) were evaluated with arterial blood collected through the inserted catheter. Diastolic arterial pressure, systolic arterial pressure and mean arterial pressure were decreased slightly in Group I IIand III, but decreased significantly in Group IV. They were increased rapidly after stopping propofol infusion in Group IV pH was maintained in normal range in Group I, II and m, but was decreased in proportion to time passing in Group IV. $PaCO_2$ was increased significantly only in Group IV but $PaO_2$ was maintained in normal range in all groups Although heart rate was recorded in normal range for 90 minutes, arythmia was noted after stopping propofol infusion in all groups. It was concluded that propofol depressed the cardiovascular system in proportion to infusion dosage, and 0.8 mg/kg/min of propofol infusion rate was not appropriated in canine anesthesia with xylazine premedication.

• 대한치과교정학회지
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• 제20권2호
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• pp.247-266
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• 1990

The alveolar bone remodeling is essential in tooth movement by orthodontic forces. The collagen and chondroitin sulfate are acting as an important roles in bone remodeling. This study was performed to measure out the quantity of the collagen and chondroitin sulfate in the alveolar bone of rats applied by experimental orthodontic forces. The 150 Sprague-Dawley male rats were divided into the $PGE_2$ treated group, indomethacin treated group and the normal group. A 80gm force rubber band was used as a orthodontic appliance between upper incisors and right upper 1st molar, and left side of experimental rats with no appliance was regarded as a control side. The samples of alveolar bones were obtained from pressure and tension sites in all three groups. respectively, and in control sides, too. The results were as follows. 1. The change in total collagen remains stable in both pressure and tension sites of all three groups, compared with control side by the time consuming. 2. The change in soluble collagen showed the most highest level in tension site, lowest level in pressure site of $PGE_2$ treated group in 5th. experimental day. 3. The change in chondroitin sulfate showed the most highest level in pressure site, lowest level in tension site of $PGE_2$ treated group in 5th. experimental day. 4. In indomethacin treated group, the change of soluble collagen and chondroitin sulfate showed small range of variance compared with $PGE_2$ treated and normal group.

• 대한약침학회지
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• 제12권2호
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• pp.41-50
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• 2009

Although Chronic tension-type headache(CTTH) is one of the most common symptom in primary headache, there is no definite mechanisms. But muscular factors and psychological factors is supposed to be related with CTTH according to many other studies and pressure pain threshold(PPT) is used to measure muscular factors. Methods 1. We performed this study with 63 patients fulfilling the International Headache Societ criteria for chronic tension-type headache and 20 healthy control group and measured the PPT of temporal muscle and trapezius muscle. 2. We investigated the correlation between clinical characteristic and PPT. 3. Each of the CTTH groups and Control group is divided to four group again - HNP, Spondylosis, Sprain, Normal according to Cervical spine X-ray. Results 1. The PPT of temporal muscle and trapezius muscle in the CTTH is significantly lower than that of Control. 2. In CTTH group, the PPT has significant positive relation with duration of headache and continued time of headache. And the PPT has significant inverse relation with Frequency of headache and Level of headache. 3. In CTTH group, spondylosis group has the highest PPT and normal group is second. And there are significant difference between spondylosis group and the others. Conclusion : We found that PPT is strongly significant to measure muscular factor in CTTH.

• 한국강구조학회 논문집
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• 제22권2호
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• pp.151-160
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• 2010

최근 기상이변으로 인한 겨울철 폭설로 농가 시설물 중의 하나인 비닐하우스의 붕괴사고가 빈번히 발생하여 농가의 피해가 증가되고 있다. 하지만 이에 대한 정부의 대책이 미약하여 매년 붕괴사고가 일어난다. 프레임 붕괴의 주된 이유는 폭설시 저항할 수 있는 휨내력이 부족하기 때문이다. 본 연구에서는 현재 이용되는 비닐하우스에 인장타이로 보강한 실험연구를 수행하였다. 비닐하우스의 스팬은 6.5m이고, 단면은 두 가지 종류(${\phi}25.4{\times}1.5$, ${\phi}31.8{\times}1.5$)를 사용하였다. 비닐하우스의 곡선 보와 직선 기둥 연결부에 임시적인 인장타이로 스틸와이어와 로프를 이용하여 보강하였다. 프리텐션을 인장타이에 적용시켰고, 적설하중을 등가의 수직하중으로 파괴할 때까지 적용하였다. 무보강과 로프 보강을 비교한 결과 로프 보강의 붕괴하중이 10∼45% 증가하였고 무보강과 스틸와이어 보강을 비교한 결과 스틸와이어 보강의 붕괴하중이 58~73% 증가하였다. 강도와 관련해서는 비교적으로 스틸와이어가 효과적이나, 연결부 및 프리텐션 적용이 로프보다 복잡하고 어려우므로 로프가 더 효율적인 것으로 판단된다.

• The Korean Journal of Physiology
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• 제7권2호
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• pp.1-8
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• 1973

온도(溫度)에 대(對)한 폐포표면활성물질(肺胞表面活性物質)의 활성도(活性度)의 태도(態度)를 구명(究明)코져 가토(家兎)의 좌측(左側) 폐장(肺臟)을 적출(摘出)하여 생리적(生理的) 식염수(食鹽水)로 폐포세척액(肺胞洗滌液)을 작성(作成)하여 4 C에 1, 5, 10, 15, 30 및 40일간(日間) 방치(放置)한 군(群)과 20 C에 1, 2, 3, 4, 5 및 7일간(日間) 방치(放置)한 군(群) 및 정상가토(正常家兎)를 4 C에 4, 8, 12 및 24 시간(時間) 노출(露出)한 후(後) 좌측(左側) 폐장(肺臟)을 적출(摘出)하고 폐포세척액(肺胞洗滌液)을 작성(作成)한 군(群)에서 그 표면장력(表面張力)을 측정(測定)하여 정상가토(正常家兎)의 그것과 비교(比較) 결과(結果)는 다음과 같다. 1) 정상가토(正常家兎)의 폐포세척액(肺胞洗滌液)의 최대(最大) 및 최소표면장력(最小表面張力)및 stability index는 각각(各各) $52.5{\pm}2.3,\;4.9{\pm}2.3$ dynes/cm 및 1.65였다. 2) 4 C에 1, 5, 10, 15, 30 및 40일간(日間) 방치(放置)한 폐포세척액(肺胞洗滌液)의 최대(最大) 및 최소표면장력(最小表面張力) 및 stability index는 각각(各各) 정상군(正常群)의 그것과 비교(比較)하여 큰 변화(變化)가 없었으며 40일군(日群)에서는 약간(若干) 증가(增加)하는 경향(傾向)을 보였으나 의의(意義)있는 변화(變化)는 아니었다. 3) 20 C에 1, 2, 3, 4, 5 및 7일간(日間) 방치(放置)한 폐포세척액(肺胞洗滌液)의 최대표면장력(最大表面張力)은 뚜렷한 변화(變化)를 보이지 않았으나 제 7 일(第 7 日)에 약간(若干) 증가(增加)하였으며 최소표면장력(最小表面張力)은 제 2 일(第 2 日)부터 증가(增加)하는 경향(傾向)을 나타내어서 제(第) 5 및 제 7 일(第 7 日)에는 현저(顯著)히 증가(增加)하였으며 그 stability index는 현저(顯著)히 감소(減少)하여 제(第) 5 및 제 7 일(第 7 日)에는 각각(各各) 0.71 및 0.53이었다. 4) 4 C에 4, 8, 12 및 24시간(時間) 노출(露出)한 가토(家兎)에서 얻은 폐포세척액(肺胞洗滌液)의 최대(最大) 및 최소표면장력(最小表面張力) 및 stability index는 각각(各各) 정상군(正常群)의 그것과 비교(比較)하여 큰 변화(變化)를 나타내지 않았으나 제(第)12시간(時間)에서 최소표면장력(最小表面張力)이 약간(若干) 증가(增加)하는 경향(傾向)을 보였으며 제(第)24시간(時間)에는 다시 정상군(正常群)의 그것과 비슷한 경향(傾向)을 나타내었다.

• The Korean Journal of Physiology
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• 제14권2호
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• pp.7-16
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• 1980

The effects of various inotropic interventions on the shape of the steady state length tension relation and the length-dependent activation process in cardiac muscle were studied. The influence of inotropic interventions upon the action potential was also observed. The range of varying muscle length was from the optimal length$(l_{max})$, where the active tension production is maximal, to 0.85 $l_{max}$. Changes in stimulus frequency or in external bathing Ca concentration constituted the inotropic interventions in this experiment. The papillary muscles were isolated from the rabbit right ventricles and perfused with $HCO-_3\;-buffered$ normal Tyrode solution which was aerated with $3%\;CO_2-97%\;O_2$ mixed gas and kept at $35^{\circ}C$. Resting Passive tension at $l_{max}$ was approximately 30% of the total tension and appeared from the muscle length of 0.90 $l_{max}$. The effect of stimulus frequency on the steady state level of developed tension was: As the stimulus frequency was increased from 0.1 to 0.5 Hz, there was little change in developed tension. As the frequency was increased further, to a value of about 3 Hz, tension increased steeply. Further increase of the frequency to 5 Hz had little additional effect on the developed tension. The length-tension curves for isometric peak tension became more steeper with the degree of potentiation by inotropic interventions. The relative steepness of the normalized length-tension curves where tension production was expressed as a percentage of maximal tension developed at $l_{max}$, varied inversely with the level of inotropic state and these curves were not superimposable one another. Thus at the stimulus frequency of 2 Hz or at the external Ca concentration of 8 mM, the relative decline in the developed tension for a given change in muscle length was considerably less than the decline observed at the frequency of 0.5 Hz or at the concentration of 2 mM Ca. Action potential duration was prolonged significantly as the frequency increased from 0.2 to 2 Hz, and this change in action potential duration was not observable on the changes in muscle length. There was a tendency of the hyperpolarization of membrane potential when the muscle length was shortened from $l_{max}$ to 0.95 $l_{max}$. These results support the hypothesis that there is a length-dependence of the activation process.