• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.110-115
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• 1998

An axisymmetric Navier-Stokes procedure has been developed to analyze the pulse jet flow in a ceramic filter unit for the dust dislodging process. Using Baldwin-Lomax turbulence model as a closure relationship, the SIAF(Scalar Implicit Approximate Factorization) algorithm together with the ${\delta}^k-Correction$ iterative time marching scheme is adopted to solve the unsteady compressible Navier-Stokes equations. After some validation tests, the code has been applied to solve the pulse jet flow and examine the effects of geometry and reservoir pressure condition on the pressure level inside the filter unit. To avoid dealing with the uncertainty of such factors as the cohesion of the collected dust and the adhesion of the dust to the medium and also to simplify the analysis, the filter wall is assumed to be impermeable. The results for various test cases are presented.

• Journal of Applied Reliability
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• v.6 no.4
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• pp.255-274
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• 2006

Recently firms become largely changed because of rapid technological innovation and serious global competition. It induces job stress of workers and finally leads to job burnout. This study aims to find the effects of job demands and job resources on job burnout. Job demands contains role ambiguity, role conflict, role overload and job characteristics. Job resources contains job control and feedback, involvement in decision making, learning opportunity and social support. The result reveals that job demands raises job burnout and job resources decreases job burnout. And it reveals that the effects of job demands and job resources on job burnout differs slightly according to job categories.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.36-36
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• 1991

기도흡인은 후두의 고유기능중 방어기능을 소실함으로써 지속되는 경우 하기도에 치명적인 손상을 초래하게된다. 기도흡인에 대한 치료는 고식적 치료법과 수술적 치료법으로 대별되는데 일반적으로 고식적으로 치료법이 우선적으로 선택되어지고 있으나 흡인의 정도가 심하여 하기도에 폐렴, 무기폐 등의 위급한 합병증을 유발하거나 그 원인이 비가역적이어서 탈진 또는 악액질을 초래하는 경우 부득이 수술적 요법율 선택하게 된다. 수술적 요법의 선택시기에 대하여는 논란이 많으나 현재까지는 고통을 받고있는 환자의 상태에 따라 결정되고 있는 실정에 있다. 저자들은 최근 5년간 경험한 만성 기도흡인 환자 6례에 대하여 수술적 요법 즉, cricopharyngeal myotomy 1례, cricopharyngeal with medialization laryngoplasty 1례, laryngeal suspension with cricopharyngeal myotomy 2례, laryngeal diversion 1례, total laryngectomy 1례를 각각 시행함으로써 얻은 치료경험을 분석 검토하여 만성 기도흡인에 대한 치료상의 문제점과 보다 효율적인 치료법의 선택에 도움을 얻고자 문헌고찰과 함께 보고하는 바이다.

• Journal of Life Science
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• v.20 no.12
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• pp.1889-1895
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• 2010

The purpose of this present study was to investigate the effects of long-term treadmill running and aged garlic extract supplementation on weight, adipose tissue mass, lipid profiles and oxidative stress after exhaustion in high fat diet-induced obese rats. Thirty male Sprague-Dawley rats (3 weeks old) were used as subjects. High fat diets were fed to all subjects for 6 weeks in order to induce obesity. The subjects were divided into five groups - N (normal diet group), HD (high fat diet group), E (exercise group), EA (exercise with AGE diet group) and A (AGE diet group). Aerobic exercise was performed through treadmill running and AGE at a dosage of 2.86 kg/g was administered to rats 30 min before every exercise for 4 weeks. After 4 weeks, all groups completed acute treadmill running (speed increasing gradually to 25 m/min, 15% uphill grade) until exhaustion. Immediately after exhaustive treadmill exercise, the weight, adipose tissue mass, lipid profiles and oxidative stress of the rats were assayed. At the end of 6 weeks of high fat diets, body weight and body weight gain were significantly higher in the high fat diet groups than in the normal diet group (p<0.001). At the end of treadmill exercise with AGE intake for 4 weeks, body weight gain, visceral and epididymal fat of the E and EA groups were significantly decreased compared to other groups (p<0.05). There were no significant differences in gastrocnemius and soleus. T-C, HDL-C, TG and LDL-C were not significant in any of the groups. TBARS was significantly lower in the A group than in the E group (p<0.05). These results indicated that body weight gain, visceral and epididymal fat decreased in the E and EA groups, and TBARS levels were lower in the A group than the E group. Regular aerobic exercise intervention with AGE supplementation may also modify the adipose weight and improve the oxidant stress in obese rats.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.101-114
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• 2015

The purpose of this study is first to understand agent's turnover from both academic and perspectives. Then we suggest convergence of smart work paradigm and supervisor's support as the relieving factors of turnover, The research model of this study is based upon reviews of turnover literature, the smart work and supervisor's support as moderating variables from which research hypotheses were derived. The data came from the survey from financial sector agents such as banking, insurance, and others. The analyses has been done by SPSS 20.0, We used multiple regressions to test the effects of the tested variables on the dependent variable, job satisfaction. The results of this study find significant relations of smart work and supervisor's supports in relations to personal and job-related turnover. The implication is smart work and supervisor's supports play significant role in increasing job satisfactions. Major finding is too much supervisor's supports ignoring agent's situations may bring reverse effects on relieving turnover.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.80-85
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• 2008

Catalytic filter is capable of performing shallow bed dust filtration plus a catalytic reaction, promoted by a catalyst deposited in its inner structure. Such a feature may allow potential cost and space reduction in several environmental applications. Dust filtration and halogenated volatile organic compound (1,2-dichlorobenzene) destruction were carried out in a lab-scale reactor. $WO_3-V_2O_5/TiO_2$ supplied by MaGreen, which showed high catalytic acitivity at low temperature, was used as a catalyst. P-84 that can be operated under $250^{\circ}C$ was used as a felt. The catalytic activity and filtration efficiency of catalytic filters were investigated under the operating conditions, including temperature, face velocity, and dust concentration. The catalytic activity of catalytic filter increased with increasing temperature and the amount of catalyst loaded. The test results showed that the filtration efficiency was primarily affected by the face velocity. Pressure drop variations as a function of time were investigated for a variety of conditions. In case of virgin filter, a dramatic decrease in the pulse interval and a slightly increase in the base line pressure drop were observed. A relatively slow pressure drop build-up was recorded for the catalytic filter due to smooth and slippery surface characteristics of nanofiber. The catalytic filter indicated that high filtration efficiency over 99.98% and high catalytic activity over 90% at 1 m/min and $210^{\circ}C$.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.349-358
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• 2018

In this study, using coke dust from ironwork, the pulse pressure on a pulse air jet bag filter was investigated considering the influence of the pressure loss due to filtration velocity and pressure intervals. The research on the optimal pulse pressure prediction of a pulse air jet type bag filter using coke dust showed the following results. Pressure loss volatility produced by the pulse pressure under low dust concentration(0.5, $1g/m^3$) and low face velocity(1.25 m/min) was less than $10mmH_2O$. This suggests that the pulse pressure has a low impact on the pressure loss. In contrast, pressure loss volatility under high dust concentration($3g/m^3$) and high face velocity(1.75 m/min) was $25mmH_2O$. Therefore, pulse pressure with high dust concentration and high face velocity has a strong influence on the pressure loss volatility, compared to the condition of low dust concentration and low face velocity. The optimal pulse pressure of inlet dust concentration($0.5g/m^3$) was $6kg/cm^2$ under the same face velocity(1.75 m/min). As concentration increased from 1 to $2g/m^3$, the pulse pressure gradually reached $5kg/cm^2$ thus indicating that the pulse pressure($5kg/cm^2$) is pertinent at a high concentration($3g/m^3$). The pulse intervals: 20, 25 and 30 sec, which are relatively longer than 10 and 15 sec, corresponded to high pressure loss volatility produced by the pulse pressure. Furthermore, low pressure loss volatility was noted at $5kg/cm^2$ of the overall pulse pressure.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.7
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• pp.391-402
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• 2017

Particulate matter becomes an important issue in the environmental society recently so that it is necessary to evaluate that the commercial application of baghouse systems for effective control of fine particulates is viable. A laboratory-scale baghouse experimental apparatus with filter bags made of PTFE felt or PTFE felt coated with PTFE membrane is used to investigate the filtration performances of fine particulates. Experiments by changing filtration velocity, inlet dust concentration, and average dust particle size show that the dust collection efficiency becomes higher at lower filtration velocity, higher inlet dust concentration and larger average dust particle size. The total pressure drop through the filter media and dust layer becomes higher at higher filtration velocity and higher inlet dust concentration. The dust collection efficiency is higher and the pressure drop is lower at a baghouse with filter bags coated with PTFE membrane than that without membrane coating. From the result that the dust collection efficiency of $PM_{2.5}$ in a reasonable filtration velocity range during off-line pulsing at a baghouse with PTFE felt bag filters coated with PTFE membrane is as high as 99.99%, it is confirmed that the use of baghouse is an effective measure to control the fine particulates.

• Journal of Life Science
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• v.20 no.2
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• pp.314-320
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• 2010

As the nature of triathlons is competition in three successive sports, triathletes experience elevated levels of stress on the body that are absent in single-sport athletic events, and consequently there are more potential medical problems to prepare for. Triathletes can also experience problems such as hypothermia, heat illness, excessive exposure to ultraviolet radiation, musculoskeletal injuries and trauma, immunosuppression, and haemolysis. Depending on the potentiality of such above-listed problems occurring in any given race, race organizers will prepare preventative measures and treatments accordingly. Olympic distance is not the only triathlon racing distance. Sprints, which are normally around half the Olympic distance, are common distances, as well as Long (2 km swim, 80 km bike, 20 km run), Ironman (3.8 km swim, 180 km bike, 42 km run), and ultra-distance events varying in length. Races of longer duration normally result in a higher percentage of athletes experiencing the above-mentioned medical problems, as well as inducing additional health risks such as hyponatraemia. Minimizing the occurrences of serious health issues is possible through the following means: carefully preparing for the probable race-day weather conditions; proper management and organization of the race; preparing an extensive water-safety and ground-course safety plan; distributing necessary nutrition along the course; and stressing the importance for athletes to have proper knowledge concerning race nutrition, biomechanical technique, physical preparation, and utilization of safe equipment. While risks of competing in triathlon are many, the instances of such medical problems are not excessive, and the triathlon has a reputation of being a reasonably safe sport as long as athletes with high risk take added precautions.

• Journal of Life Science
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• v.20 no.9
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• pp.1345-1352
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• 2010

We investigated the effect of brown-rice vinegar (BRV) ingestion after strenuous Wingate tests on energy substrates during a 2 hr recovery period. For this, seven healthy male adolescents were chosen as subjects. They performed 3 Wingate tests to induce fatigue, after which they ingested brown-rice vinegar (BRV) drink and/or water as a control (CON) after 15 min of the test. Blood was obtained pre-exercise and 30 min, 60 min, and 120 min post-exercise, and blood glucose, lactate, free fatty acids, ammonia, and cortisol were analyzed. After 120 min of recovery period, the 4th Wingate test was conducted to calculate the power recovery ratio of the 3rd and 4th trials. Breathing frequency, oxygen saturation, and heart rate did not show significant changes. Blood glucose level was lower in CON than BRV after 120 min of recovery, and blood lactate and ammonia levels were lower in BRV at 60 and 120 min. The higher free fatty acids were found at 60 and 120 min in BRV. In addition, Wingate power recovery ratio of peak power and peak power/body weight was significantly higher in BRV compared to CON. These results suggested that BRV ingestion after strenuous exercise facilitates fatigue recovery. Therefore, BRV might be effectively used as an ergogenic aid for events in which competitors compete two or more times a day.