• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.10-17
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• 2018

The size of commercial wind turbines has been increased. Generally, the pitch control is used to increase the efficiency of wind turbine. However, the pitch control has difficulty to control the local unsteady flow control which makes fatigue load and decreases the efficiency. In this research, Synthetic Jet Actuators(SJAs) are manufactured and applied into a wing section to delay flow separation and increase aerodynamic performances. The SJAs as a kind of zero-net mass-flux actuators injects and removes fluid through a small orifice with a given frequency. The SJA modules actuated by piezoelectric disks are manufactured and the aerodynamic performances are measured according to the shape of the orifice and the velocity of the jets through the wind tunnel test. It is confirmed that as the velocity of the jets are increased using rectangular shape orifice, drag force is decreased and lift force in increased.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.24-31
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• 2011

Rectangular box type structures are used in many fields of civil, mechanical and marine engineering. Especially, Most ship structures are often in contact with inner or outer fluid, like ballast, fuel and stem tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine and propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tanks. Many authors have studied vibration of rectangular tanks containing fluid. Few research on dynamic interaction among tank walls filled with fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass of water have to be considered. In the previous report, a numerical analysis is performed for the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing breadth of the plates by using finite element method for plates and boundary element method for fluid region. In this paper, the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region, and mode characteristics in accordance with changing length, thickness, and boundary condition of the plates are investigated numerically and discussed.

• Korean Parent-Child Health Journal
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• v.7 no.2
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• pp.168-181
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• 2004

Purpose: The purpose of this study was to identified patterns of studies and to analyze the nursing research related to the massage intervention in Korea and to improve direction of nursing research in massage intervention in Korea. Methods: The research studies related to the massage were selected from the Korean Nurses Academic Society Journal and dissertation which were conducted experimental research design the last 7 years in Korea. The total numbers of the studies were 58. Result: The study subjects were post operational state in 34.5%, healthy adult in 17.2% studies. The others dealt with infant, cancer, dementia, hypertension, preterm neonates, elderly. Types of massage were whole body in 31.1%, foot in 22.6%, hand in 17.2%, back in 13.8% studies. And Meridian massage in 17.2%. Length of massage was below 5 minutes in 17.2%, 6~10 minutes in 29.4% and 11~20 minutes in 32.8% studies. Frequency of massage was only 1 time in 25.9%, 2~5 times in 31.1% studies. Massage produced psychological and physiological effects. Positive psychologic effects were anxiety relief, pain relief, mood enhancement and fatigue relief. Positive physiologic effects on body systems were blood pressure, heart rate, edema, skin temperature, immune system, blood glucose, excretion, PMS syndrome and growth and development. Conclusion: As a result, effects of massage were almost positive. Therefore massage is useful alternative nursing intervention. But more attention research is needed to identify the objectivity instrument to measure and repeat research.

• Herbal Formula Science
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• v.12 no.2
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• pp.1-17
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• 2004

This study was investigated to make sure the range of the Morus Cortex's treatment, the nature of disease, the chief virtue of medicine, the pathology and the usage quantity of it in Donguibogam The results were as follows; 1. The frequency of being used the Morus Cortex in the consumption or cough-relative chapter is as high as a ratio of 40.6%. 2. The Morus Cortex is used in a realm of the consumption or cough-relative disease, an otorhinolalyngology, an edema, a skin-relative disease, a bleeding trouble, a thirsty and diabetes melitus, etc. 3. The Morus Cortex is used in a realm of the pathology of the pulmonary heat, the pulmonary noxious vigor, the damage from external winds and colds, fatigue, etc. 4. The Morus Cortex is used in a range of $1g{\sim}12g$ in herbal-prescription. The main using dosage is 4g(about 42%). 5. The Morus Cortex is used with various crude herbs in accordance with the pathogeny. The Morus Cortex has been used to reduce heat from the lungs and soothe asthma, to promote urination and reduce edema from shinnongboncho era. According to the results, I suggest that we use the Morus Cortex in a various pathogenic fields. The Morus Cortex is able to remove not only pathogenic heat from the consumption or cough-relative disease, but also pathogenic otorhinolalyngology, an edema, a skin-relative disease, a bleeding trouble, a thirsty and diabetes melitus, etc.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.26-31
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• 2013

The reduction unit is one of the most important components for railway vehicles because the torque of the motor must be transmitted to the wheels of the vehicle by the reduction unit. The faults in the reduction units of high-speed trains are caused by damage such as gear, fatigue. These have serious impacts on safety of the train during operation. To address this development of a system for monitoring, fault diagnosis of the reduction unit is needed to keep the vehicle running safely. Before that can be accomplished, it is most important to understand the vibration characteristics of the reduction unit in a normal state. Vibration diagnosis technology using characteristic-analysis of vibration waveform and frequency is known to be the most effective method for fault diagnosis. In this paper, we analyzed the vibration characteristics of the reduction units two Korean high-speed trains (KTX and KTX II), under normal conditions, by two test methods (driving gear test, full-vehicle test).

• The Journal of Korean Medicine
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• v.27 no.1 s.65
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• pp.1-10
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• 2006

Objectives : The combined treatment (CT) with oriental herbal medicine and western biomedical medicine is prevalent in the world including Korea. But the clinical information on frequency, efficacy and safety of CT at lout cerebrovascular attack hat not known thoroughly yet. This study aimed to identify the status and adverse effects of CT for the treatment of stroke patients. Methods : A self-completed questionnaire survey and medical record survey by oriental medical doctors were performed in 20 Korean Oriental medical hospitals. Of the initial 1,000 in-patients through 2-stage sampling method, 883 were participated in this surrey, resulting in a response rate of 88.3%. Results : Among stroke patients, the proportion of CT was 94.1%. 156 respondents (18.8%): were experienced several adverse effects including headache, dizziness (fatigue), diarrhea, constipation, chest discomfort, etc. The severity of these adverse effects was generally mild to moderate. Although they quitted the CT, 9.8% of patients were not relieved from adverse effects. Conclusions : This study suggests that most patients in Korean Oriental medical hospitals used the combined treatment with oriental herbal medicine and western biomedical medicine for management of stroke. Therefore, the medical professionals should provide comprehensive and up-to-date clinical information about potential benefits and risks of CT to the stroke patients.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.1172-1177
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• 2009

This study is to determine the effects of BUDDEUMI(moxibustion and cupping a boli) therapy on the relief of shoulder pain among middle aged women. methods : A total of 39 middle aged women with shoulder pain are selected : 20 in the experimental group and 19 in the control group. The data was collected by using questionnaires. The BUDDEUMI(moxibustion and cupping a boli) therapy on the should and back was administered to the experimental group, and no treatment was given to the control group. All of the subjects were examined on a subjective symptom scale and on the grade of discomfort and pain in everyday life as developed by Japan's Industrial Fatigue Research Committee of the Industrial Hygienics Society(1988), Sohn, Mong Ho(1999), Visual Analogue Scale as developed by Cline (1992). SPSS/win 12.0 was used for Date analysis, General features demonstrated by frequency number and percentage. The effects of the BUDDEUMI(moxibustion and cupping a boli) therapy was analyzed by a t-test. The homogeneity testing revealed that all study variables are equally distributed between experimental and control groups. The hypothesis, 'the experimental group who received BUDDEUMI(moxibustion and cupping a boli) therapy will decrease in the grade of discomfort of shoulder', is supported. The hypothesis, 'the experimental group who received BUDDEUMI(moxibustion and cupping a boli) therapy will decrease in the Visual Analogue Scale is supported. Conclusion : As a result of this study, BUDDEUMI(moxibustion and cupping a boli) therapy will be able to be used as the self care therapy to improve the symptoms of middle aged women who has the shoulder pain.

• Coupled systems mechanics
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• v.7 no.4
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• pp.485-507
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• 2018

The moving load causes the occurrence of vibrations in civil engineering structures such as bridges, railway lines, bridge cranes and others. A novel engineering method for separation of the variables in the differential equation of the elastic line of Bernoulli-Euler beam has been developed. The method can be utilized in engineering structures, leading to "a beam under moving load model" with generalized boundary conditions. This method has been implemented for analytical study of the dynamic response of the metal structure of a single girder bridge crane due to the telpher movement along the bridge girder. The modeled system includes: a crane bridge girder; a telpher, moving with a constant horizontal velocity; a load, elastically fixed to the telpher. The forced vibrations with their own frequencies and with a forced frequency, due to the telpher movement, have been analyzed. The loading resulting from the telpher uniform movement along the bridge girder is cyclical, which is a prerequisite for nucleation and propagation of fatigue cracks. The concept of "dynamic coefficient" has been introduced, which is defined as a ratio of the dynamic deflection of the bridge girder due to forced vibrations, to the static one. This ratio has been compared with the known from the literature empirical dynamic coefficient, which is due to the telpher track unevenness. The introduced dynamic coefficient shows larger values and has to be taken into account for engineering calculations of the bridge crane metal structure. In order to verify the degree of approximation, the obtained results have been compared with FEM outcomes. An additional comparison has been made with the exact solution, proposed by Timoshenko, for the case of simply supported beam subjected to a moving force. The comparisons show a good agreement.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.3
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• pp.1-7
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• 2003

The crystallized stable cobalt silicide$(CoSi_2)$ films were prepared on $poly-Si/SiO_2/Si$substrates for the application of inkjet printing head as a heating element with omega shape. The structural images and temperature resistance coefficient were investigated. The value of temperature resistance coefficient of the heating element was found to be about $0.0014/^{\circ}C$. The maximum power of the heating element was 2 W at the applied voltage of 2 V, 10 kHz in frequency and $1{\mu}s$ in pulse width. From the investigation of fatigue property according to the repeated applied voltages, there was no drastic changes in the resistances of heating element under the condition of $10^8$ pulsed cycles at below 15 V biased voltage. In contrast, the resistance of heating element was greatly increased at $10^6$ pulsed cycles when the heating element was operated at 17 V.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.21-30
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• 2018

Driven by the recent energy saving trend, conventional silicon based power conversion modules are being replaced by modules using silicon carbide. Previous papers have focused mainly on the electrical advantages of silicon carbide semiconductors that can be used to design switching devices with much lower losses than conventional silicon based devices. However, no systematic study of their thermomechanical reliability in power conversion modules using finite element method (FEM) simulation has been presented. In this paper, silicon and silicon carbide based power devices with three-phase switching were designed and compared from the viewpoint of thermomechanical reliability. The switching loss of power conversion module was measured by the switching loss evaluation system and measured switching loss data was used for the thermal FEM simulation. Temperature and stress/strain distributions were analyzed. Finally, a thermal fatigue simulation was conducted to analyze the creep phenomenon of the joining materials. It was shown that at the working frequency of 20 kHz, the maximum temperature and stress of the power conversion module with SiC chips were reduced by 56% and 47%, respectively, compared with Si chips. In addition, the creep equivalent strain of joining material in SiC chip was reduced by 53% after thermal cycle, compared with the joining material in Si chip.