• Title/Summary/Keyword: fatigue measurement

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Fabrications and Properties of VF2-TrFE Films for Nonvolatile Memory Application (비휘발성 메모리 응용을 위한 VF2-TrFE 박막의 제작 및 특성)

  • Jeong, Sang-Hyun;Byun, Jung-Hyun;Kim, Hyun-Jun;Kim, Ji-Hun;Kim, Kwang-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.388-388
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    • 2010
  • In this study, Ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer films were directly deposited on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE = 70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000 ~ 4000 rpm for 2 ~ 30 seconds. After annealing in a vacuum ambient at 100 ~ $200^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on highly doped Si wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the copolymer films have ferroelectric properties. The typical measured remnant polarization ($P_r$) and coercive filed ($E_c$) values were about $5.7\;{\mu}C/cm^2$ and 710 kV/em, respectively, in an applied electric field of ${\pm}$ 1.5 MV/em. The gate leakage current densities measured at room temperature was less than $7{\times}10^{-7}\; A/cm^2$ under a field of 1 MV/cm.

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Difference of Pinch Strength According to Testing Posture and Various Flexion Degree of Elbow Joint

  • Lee, Hang-Eun;Yang, Jin-Kyu;Son, Jin-Hee;Hwang, Bo-Young;Kim, Mun-Kyo;Ha, Mi-Suk;Kim, Jae-Heon
    • Journal of International Academy of Physical Therapy Research
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    • v.1 no.2
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    • pp.113-119
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    • 2010
  • The purpose of this study was to determine the difference of the pinch strength according to testing posture(standing and sitting) and elbow flexion degree($0^{\circ}$, $45^{\circ}$, $90^{\circ}$ and $135^{\circ}$). Forty normal young adults(male: 20, female: 20, mean age: $22.68{\pm}2.91$ years) participated in this study. The methods of this study were categorized as follows: 1) One set of measurement was performed on four elbow flexion degrees($0^{\circ}$, $45^{\circ}$, $90^{\circ}$ and $135^{\circ}$) in two testing postures(standing and sitting) and all subjects were measured for 3 sets testing procedures in every experimental sessions. 2) Pinch strength in various elbow flexion degree was measured after 2 min rest time, and then each test set was repeatedly performed with 5 min rest time to prevent fatigue of muscles involved in the elbow joint. The result was obtained as follow: 1) In standing posture, there was statistically significant difference at $0^{\circ}$ and $45^{\circ}$, $0^{\circ}$ and $90^{\circ}$, $0^{\circ}$ and $135^{\circ}$, $45^{\circ}$ and $90^{\circ}$, $45^{\circ}$ and $135^{\circ}$, $90^{\circ}$ and $135^{\circ}$. 2) In sitting posture, there was statistically significant difference at $0^{\circ}$ and $45^{\circ}$, $0^{\circ}$ and $90^{\circ}$, $0^{\circ}$ and $135^{\circ}$, $45^{\circ}$ and $90^{\circ}$, $45^{\circ}$ and $135^{\circ}$, $90^{\circ}$ and $135^{\circ}$. 3) Statistically, there was no significant difference between standing and sitting posture in same elbow flexion degree, however pinch strength in standing posture was higher than sitting posture.

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The Immune-Enhancing Effect of Mountain Gown ginseng, Mountain Cultivated ginseng, and Panax ginseng (산삼(山蔘), 장뇌삼(長腦蔘), 인삼(人蔘)의 면역증강(免疫增强)효과 비교연구)

  • Chung, Dae-Kyoo;Kwon, Soon-Joo
    • Journal of Oriental Neuropsychiatry
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    • v.15 no.2
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    • pp.89-101
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    • 2004
  • Objective : The present experiments were designed to study on the immune-enhancing effect of Mountain grown ginseng, Mountain cultivated ginseng, and Panax ginseng Method : In order to compare the immune-enhancing effect of moutain grown ginseng, moutain cultivated ginseng and Panax ginseng, the study was done through the forced swimming test (FST), measurement of T helper Th1, Th2 cytokines and fatigue related factors. Result : Moutain grown ginseng and panax ginseng decreased the immobility time in the FST compared to the control. Glucose, blood urea nitrogen (BUN), creatinine, lactate dehydrogenase (LDH) and Total-protein (T-protein) in serum were investigated. The serum achieved from ginseng administered mouse showed higher BUN, T-protein than the control. moutain grown ginseng administered group showed lower LDH than the control group. moutain grown ginseng administered mouse showed higher glucose than the control. Creatinine was same in either experimental or control group. Ginseng-induced cytokine production in human T-cell line, MOLT-4 cells and mouse peritoneal macrophages were compared. Moutain cultivated ginseng (10-4 dilution) and panax ginseng (10-3 dilution) were increased the interferon $IFN-{\gamma}$ production compared with media control (about 1.6-fold P<0.05) at 48 h. Moutain grown ginseng (10-4 dilution) was increased the $IFN-{\gamma}$ and interleukin IL-4 production compared with media control (about l.4-fold for $IFN-{\gamma}$ and 1.6-fold for IL-4 P<0.05) at 48 h. Moutain grown ginseng (10-3 dilution) and moutain cultivated ginseng (10-4 dilution) were increased the turmor necrosis factor $TNF-{\alpha}$ production compared with $rIFN-{\gamma}$ treated cells (about 1.9-fold for $TNF-{\alpha}$ P<0.05), respectively. Moutain cultivated ginseng (10-3 dilution) was increased the IL-12 production compared with $rIFN-{\gamma}$ treated cell (about 1.7-fold for IL-12 P<0.05). Conclusion : These data suggest that three different three kinds of ginseng act on immune responses in different aspects.

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A Comparative Study on the Dietary Habits, Life Habits, Physical Symptoms and Body Composition of University Students by Gender Differences in Incheon City (인천지역 남녀 대학생들의 식습관, 건강관련 생활습관, 신체증상 및 체성분에 관한 비교 연구)

  • Jang, Jae-Seon;Hong, Myung-Sun
    • The Korean Journal of Food And Nutrition
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    • v.26 no.4
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    • pp.928-935
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    • 2013
  • This study was designed to investigate the dietary habits, life habits, physical symptoms, and body composition of male and female students attending college in incheon, based on which to encourage proper dietary habits among and enhance the physical and psychological health of college students. The effects of personal characteristics (such as gender, grade level, residence type, means of transportation), health relative life habits (exercise, smoking and alcohol consumption), dietary habits, physical symptoms and body composition measurement were analyzed by using the questionnaire and Inbody. The subject pool was composed of 96 male and 149 female students. Smoking, drinking, exercise, and fruit intake showed significant differences between the genders (p<0.05), whereas meat intake was not significantly different (p>0.05). Differences on dietary habits and the intake of fruit showed significant differences (p<0.05) between the genders. Especially, more female than male students showed a higher frequency of fruit intake. Physical symptoms such as headache, common cold, dizziness, easy fatigue, poor concentration, indigestion and constipation showed significant differences (p<0.05) between the genders, whereas stomatitis, anorexia and pale face were not significantly different (p>0.05). Differences between the genders on body composition, height, weight, BMI, muscle soft lean mass, body fat mass, skeletal muscle mass and waist-hip ratio were also significantly different (p<0.05). The correlation analysis of college students by gender was negative between intake of milk and physical symptoms (p<0.01), whereas intake of cooked food and physical symptoms showed a positive correlation (p<0.01, p<0.05).

The Physiological Responses of Material-improved Working Clothes for Construction Site Worker (건설현장 작업복의 소재 기능성 향상에 따른 생리반응)

  • Kim, Seong-Suk;Kim, Hee-Eun
    • Fashion & Textile Research Journal
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    • v.13 no.5
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    • pp.752-758
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    • 2011
  • In this paper, experiments to develop working clothes and evaluated, including the current and material-improved working clothes in relation to physiological functionality measurement. Experiments were conducted on subjects after wearing working clothes in an climate chamber, and the thermo-physiological response, such as human body temperature, micro-climate within the clothes, blood pressure, heart rate were measured. In this manner, the physiological functionality of improved working clothes was compared with that of current working clothes and evaluated. The summary of obtained results is as follows: For physiological functionality evaluation through material-improved working clothes, P working clothes showed significantly lower rectal temperature than C working clothes. For mean skin temperature, P's skin temperature was significantly higher than C's in the second half of the experiment. P working clothes's temperature around the thighs in Micro climate was significantly lower than that of the C working clothes. Also, humidity within the clothes showed similar trends. During the exercise period, C working clothes showed higher blood pressure than P, but P showed higher heart rates than C. Also, the oxygen uptake amount was higher in C than P during the exercise period, it explains that the energy consumption amount of P working clothes was smaller than that of C working clothes. Of the subjective evaluation, for temperature sensation, workers wearing P working clothes felt cooler. For humidity, C working clothes showed more humidity. For comfort, P working clothes were better, and for sense of fatigue, workers felt less tired wearing P working clothes. From results above, we can see that physiological functionality improved in the material-improved working clothes in the working clothes for construction site workers. The improvement of working clothes through functionality improvements not only will provide personal pleasantness to constriction site workers, but will also generate efficiency and productivity improvements at construction sites. All in all, the continuous study of functionality improvements in working clothes taking into consideration the human body's physiological responses is required.

The Evaluation on Functionality with Material-improved Working Uniform of Construction Field (소재개선에 따른 건설현장 작업복 착의기능성 평가)

  • Kim, Seong-Suk;Kim, Hee-Eun
    • Fashion & Textile Research Journal
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    • v.10 no.2
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    • pp.228-235
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    • 2008
  • The purpose of this study is to examine the functionality with material-improved working uniform(protocol, P) and current working uniform(control, C). Movement functionality evaluation of material-improved working uniform was carried out through sensory evaluation of working uniform. And Oxygen uptake was explored to different working uniform(P, C) in relation to a physiological functionality measurement. The results have been shown as follows: It was found that the workers feel uncomfortable with the parts of the wrist, the back width, the shoulder seam and the side in the current working uniform when they move their arms up and down, but the inconvenience has been reduced in the material-improved working uniform. And It was found that the workers feel uncomfortable with the parts of the back width, the wrist and the side seam of the jacket, and the waist, the hips and the thigh of the trousers in the current working uniform when they move their waist, but the inconvenience has been reduced in the material-improved working uniform. In the current working uniform, it was also found that they feel uncomfortable with the parts of the horse riding position in which they stand straight in their slightly bended knees, with the parts of the hips, the side seam, the thigh and the knees when they crouch down, and with the parts of the hips and the thigh when they put one of their legs onto a higher place. However, the inconvenience was reduced in the material-improved working uniform. Oxygen uptake, which was measured to assess physiological dressing functionality, was found to be higher when people work in an uncomfortable uniform than when they work in a uniform of better functionality by an increase in metabolic rate, which can be a cause of workers' inefficiency of fatigue.

Prediction of Fatigue Life in 2 Ply Rubber/Cord Laminate (2층 고무/코드 적층판의 피로 수명 예측)

  • 임동진;이윤기;윤희석;김민호
    • Composites Research
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    • v.16 no.3
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    • pp.9-17
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    • 2003
  • In order to simulate the crack connection between cords and the interply crack growth in the belt-layer of real tire, 2 ply rubber/cord laminate specimens with exposed edges were tested in 4~11mm displacement control. Measurement of the crack connection is evaluated when crack reaches the half of the length between 45$^{\circ}$ aligned cords, and the amount of the crack growth is measured by the steel probe method. 2 dimensional analytic modeling was performed to simulate the crack connection between cords at the exposed edges. Also, the theoretical life of the specimens was calculated from the crack connection life between cords(critical value) and from the critical value to the final failure by the use of Tearing energy(T); the strain energy release per unit area of one fracture surface of a crack. Then, theoretical life was compared with those of experiments. The life prediction up to the critical value has about 20% error compared to experimental life, and up to the final failure about 65% error. Therefore, total theoretical life has about 45% error compared to the experimental life, which is conceivable in the case of rubber.

Tool Condition Monitoring with Non-contacting Sensors in Inconel 718 Milling Processes (비접촉센서를 이용한 Inconel 718 밀링가공에서 공구상태 감시)

  • Choi, Yong-Ki;Hwang, Moon-Chang;Kim, Young-Jun;Park, Kwang-Hwi;Koo, Joon-Young;Kim, Jeong-Suk
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.6
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    • pp.445-451
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    • 2016
  • The Inconel 718 alloy is a well-known super-heat-resistant alloy and a difficult-to-cut material. Inconel 718 with excellent corrosion and heat resistance is used in harsh environments. However, the heat generated is not released owing to excellent physical properties, making processes (e.g., adhesion and thermal fatigue) difficult. Tool condition monitoring in machining is significant in reducing manufacturing costs. The cutting tool is easily broken and worn because of the material properties of Inconel 718. Therefore, tool management is required to improve tool life and machinability. This study proposes a method of predicting the tool wear with non-contacting sensors (e.g., IR thermometer for measuring the cutting temperature and a microphone for measuring the sound pressure level in machining). The cutting temperature and sound pressure fluctuation according to the tool condition and cutting force are analyzed using experimental data. This experiment verifies the effectiveness of the non-contact measurement signals in tool condition monitoring.

Clinical trial for efficacy and safety with acupuncture & suction in nasal cavity on snoring patients (코골이 대상자에게 비강사혈흡인요법의 안전성과 유효성을 평가하기 위한 다기관 임상시험)

  • Shin, Mi-Ran;Kim, Hee-Taek;Ko, Ho-Yeon;Kim, Young-Ji;Kim, Jeung-Beum
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.30 no.2
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    • pp.135-145
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    • 2017
  • Objectives : The study is to investigate clinical trial for efficacy and safety with acupuncture & suction in nasal cavity on snoring patients. Methods : 24 subjects were recruited from the patients received a hospital visit to the Semyung University Chungju oriental medical center and Jaechon oriental medical center from 1 October 2014 to 31 December 2014. According to the clinical protocol, we treated the patients with acupuncture and suction in the nasal cavity 8 times for 4 weeks. We compared their symptoms between before and after treatment. Results and Conclusions : 1. There was no significant decrease in the mechanical measurement of the reduction of snoring in the effectiveness of snoring patients, but there was a significant effect on the improvement of sleep quality and it was effective in improving the symptoms such as eye fatigue. 2. The safety of nasal treatment for snoring patients was normal in pre- and post-treatment Lab tests, and there was no adverse reaction before and after treatment. Acupuncture & suction in nasal cavity on snoring patients is efficient and safe.

근육 피로도 분석시 사용되는 매개변수들간의 민감도 비교 연구

  • 정명철;김정룡
    • Proceedings of the ESK Conference
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    • 1997.10a
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    • pp.406-413
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    • 1997
  • 근전도(EMG:Electromyogram)를 사용하여 국부 근육 피로(Localized Muscle Fatigue)를 정량화으로 분석 하기 위해 널리 이용되고 있는 AR(Autoregressive)모델의 1차 계수, RMS(Root Mean Square), ZCR(Zero Crossing Rate), MPF(Mean Power Frequency), MF(Median Frequency)를 선택하여, 근육이 발휘하는 힘과 시간의 흐름에 따라 근육 피로의 정도를 민감하게 나타내는 매개변수를 규명하였다. 피실험자 10명의 좌우 척추세움근(Erector Spinae Muscle)을 대상으로 등장수축(Sustained Isometric Contraction)조건에서 허리의 신전(Extension)운동을 실시하였다. 이때 발휘해야 하는 힘의 수준은 15%, 30%, 45%, 60%, 75% MVC 로 정하였고 각 수준마다 20초 동안 근전도를 측정하 였다. 데이터 분석은 총20초 구간의 근전도를 0.5초 간격으로 나누어 매개변수들을 각각 구하고 분석을 실시하였다. 시간의 흐름에 대한 피로도 분석 결과, AR 모델의 1차 계수와 MPF가 유의한 차이를 보였으며, 낮은 수준의 %MVC에서는 AR 계수가, 높은 수준에서는 MPF가 민감한 반응 결과를 나타냈다. 그리고 근육이 발휘하는 힘의 정도를 분석하기 위해 주로 사용되고 있는 RMS 보다는 더 AR 계수가 모든 수준에서 뚜렷하게 차이를 보인 것이 확인되었다. 따라서 AR 모델의 1차 계수가 근육의 피로 정도와 힘의 수준을 다른 매개변수에 비해 더욱 민감하게 구별함이 입증되었다. 이러한 결과는 다른 분야에서도 근육 피로를 정량적으로 측정하는데 사용될 수 있을 것으로 생각되며, 개인적 변이도를 고려한 확률 기법을 사용한다면 보다 정확한 근전도 분석이 이루어질 것으로 기대된다.있음을 알 수 있었다. 사료된다.의 결과는 자전거 에르고노미터의 결과가 트레드밀의 결과에 87.60%정도 나타났다.음을 관찰하였다. 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.mance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business portfolio properties, we obtained three findings. First, only VI (Vertical integration) has a significant positive correlation with ROS. Second, when using TFP growth as an dependent variable, both TR(Technological Relatedness) and f[ are signif

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