• Women's Health Nursing
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• 제7권3호
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• pp.359-372
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• 2001

The study was intended to investigate the bothersome level of premenstrual symptoms, their pattern and to examine the relationships between menstrual attitude and the premenstrual symptoms. Two hundred sixty eight female students were recruited from a college located in Kyungido from March 1, 2001 to July 1, 2001. A general characteristics questionnaires, the premenstrual assessment form(PAF) and the menstrual distress questionnaire(MDQ) were used to measure the bothersome level of the premenstrual symptoms and the menstrual attitude. The data were analyzed by SPSS-PC+ program. The results of this study were as follows ; 1. All subject who were participated in the research reported more than one symptom in premenstrual period and the mean score of total categories in PAF was low(1.89). The subject had more symptoms of fatigue, abdominal bloating and discomfort, backache and muscle stiffness and among the 21 categories fatigue feature, hysteroid feature, water retention feature and miscellaneous mood/behavior change feature were prevalent. On the other hand organic mental feature and increased well-being feature were rare that premenstrual symptom has negative aspect than positive. 2. Degree of discomfort in premenstrual symptom was related with dysmenorrhea but other general characteristics. 3. In Menstruation attitude, the student in college recognized menstruation as natural but bothersome and causes negatives effects on body and emotion. 4. There were significant correlation(r=.395, p<0.000) between premenstrual symptom and level of Menstrual attitude. 5. Menstrual attitude explained 15.3% variance of PMS and five categories of menstrual attitude, especially factor 1(menstruation is a phenomena that weakens women physically and psychologically) was most highly correlated with PMS and explained 21.1% variance of PMS.

• Journal of muscle and joint health
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• 제6권1호
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• pp.22-36
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• 1999

The purpose of the study was to identify disease characteristics and behavior pattern of treatment for patients with Fibromyalgia. This study was carried out between May to Aug. in 1998 through direct interview in Rheumatism clinic at H. University Hospital and subject in this study were 125 outpatients diagnosed with Fibromyalgia. Collected data were analyzed by descriptive statistics and t-test, ANOVA using SPSS Window program. The results of this study are as follows. 1. General Characteristics : All of the persons with Fibromyalgia were female who were mostly in their forties(37.5%). A third of them(38.4%) were graduated from high school. The greatest part of them(54.4%) were christians but little part of them(16.8%) were employed 2. Disease Characteristics : They have struggled with Fibromyalgia for 10 years on an average. About half of them(56.9%) suffered from Fibromyalgia only but the others had another diseases which were in greatest part occupied by Osteoarthritis. The number of tender point which is a feature of Fibromyalgia differed according to measuring criteria. Yunus criteria. however, was proved to be the most proper measuring criteria than any other method as it showed high correlations between symptoms and physical activities. The most serious symptoms that complained the patients among subjective symptoms are pain, sleep disorder, and fatigue in sequence, and activities most hard to do among physical activities are washing by hand, scrubbing by hand, and shopping in sequence. 3. Behavior Pattern of Treatment : The largest part of them(42.4%) had received medical treatment after they were determined to have the disease and most of them were taking medicine as prescribed by physician(88.8%) or other medicines(16.8%), Of them, two thirds stated that the medicine they took were effective. Around a third of them took exercises mostly composed of swimming. The medical institution they visited in the past were orthopedic surgical department, Oriental hospital, physical therapy department in sequence and, in a slight percent(11.4%), psychiatric department. 4. Relations between Disease Characteristics and Behavior pattern of Treatment : It shows that number of tender point and level of symptom are significantly different according to duration of disease and medical intervention. As a results, it can be suggest that persons with Fibromyalgia need to take exercises and medicine continually regardless of medical treatment as it is a chronic disease whose symptoms are hardly mitigated.

• Journal of the Microelectronics and Packaging Society
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• 제30권4호
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• pp.105-111
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• 2023

Electronic devices have been evolved to be mechanically flexible that can be endured repetitive deformation. This evolution emphasizes the importance of long-term reliability in metal wiring connecting electronic components, especially under bending fatigue in compressed environments. This study investigated methods to enhance adhesion between copper (Cu) and polyimide (PI) substrates, aiming to improve the reliability of copper wiring under such conditions. We applied oxygen plasma treatment and introduced a chromium (Cr) adhesion layer to the polyimide substrate. Our findings revealed that these adhesion enhancement methods significantly affect compression fatigue behavior. Notably, the chromium adhesion layer, while showing weaker fatigue characteristics at 1.5% strain, demonstrated superior performance at 2.0% strain with no delamination, outperforming other methods. These results offer valuable insights for improving the reliability of flexible electronic devices, including reducing crack occurrence and enhancing fatigue resistance in their typical usage environments.

• Proceedings of the Acoustical Society of Korea Conference
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.912-918
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• 1994

Poor speech intelligibility in an air traffic control room is frequently a result of many, quite different causes and occasionally leads to complaints of the controller personnel. The paper describes a sequence of successful tasks performed in a local control room. The initial measurements included an investigation of the background noise (caused by fans, air condition, computer and radar equipment) and performance checks of the electronic audio and communication equipment with respect to the audio transmission behavior. The spectral composition of the noise as well as the characteristics of the audio communication path between the controllers and the pilots(which showed a loss of spectral information in the audio band due to built-in notch filters for the suppression of control tones) required adaptations of the amplitude behavior of the amplifiers through user adjustable tone controls. The radar console fans, which contributed significantly to the overall noise floor of the room, underwent a substantial reconstruction by replacing the tight mounting with an elastic double suspension, reducing the noise level by 50%. Finally, a possible source of untimely fatigue of the controllers during their working hours has been found in strong spectral components of the noise above the audio band, radiated by numerous video monitors in the control through vibrating components excited by the line frequency of the video signal.

• Journal of the Korean Society for Heat Treatment
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• 제8권1호
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• pp.75-83
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• 1995

The purpose of this study is to investigate the effect of heat treatments on the martensite transformation and tensile deformation behavior in Ti-Ni-B alloys with various boron concentration. Three types of heat treatment are given to the specimens; i) solution treatment ii) aging iii) thermo-mechanical treatment. In solution treated specimens. R-phase transition which is related to abnormal increase of electrical resistance prior to martensitic transformation has been formed at a boron content of 0.2at % and the $M_s$ temperature has been decreased with the increasing of boron content. However. It has not been affected by aging, while that of thermo-mechanically treated specimens has been remarkably increased in the vicinity of recrystallization temperature. The thermo-mechanically treated specimen has showed a good thermal fatigue characteristics, shape memory effect and superelasticity in comparison with the solution treated specimen.

• Journal of Powder Materials
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• 제30권6호
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• pp.478-483
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• 2023

High-entropy alloys (HEAs) are characterized by having five or more main elements and forming simple solids without forming intermetallic compounds, owing to the high entropy effect. HEAs with these characteristics are being researched as structural materials for extreme environments. Conventional refractory alloys have excellent high-temperature strength and stability; however, problems occur when they are used extensively in a high-temperature environment, leading to reduced fatigue properties due to oxidation or a limited service life. In contrast, refractory entropy alloys, which provide refractory properties to entropy alloys, can address these issues and improve the high-temperature stability of the alloy through phase control when designed based on existing refractory alloy elements. Refractory high-entropy alloys require sufficient milling time while in the process of mechanical alloying because of the brittleness of the added elements. Consequently, the high-energy milling process must be optimized because of the possibility of contamination of the alloyed powder during prolonged milling. In this study, we investigated the high-temperature oxidation behavior of refractory high-entropy alloys while optimizing the milling time.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제26권11호
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• pp.2328-2335
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• 2002

A hybrid composite material has many potential usage due to the high specific strength and the resistance to fatigue, when compared to other composite materials such as fiber reinforced plastic(FRP) and metal matrix composite(MMC). However, the fracture mechanism of hybrid composite material is extremely complicated because of the bonding structure of metals and FRP. In this study, Al 7075 sheets and carbon epoxy preprags were used to fabricate the hybrid composite. Recently, nondestructive technique has been used to evaluate the fracture mechanism of these composite materials. AE technique was used to clarify the microscopic damage behavior and failure mechanism of A17075/CFRP hybrid composite. It was found that AE paralneters such as AE event, energy and amplitude were effective to evaluate the failure process of Al 7075/CFRP composite. In addition, the relationship between the AE signal and the characteristics of fracture surface using optical microscope was discussed.

• Journal of the Society of Disaster Information
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• 제14권4호
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• pp.492-500
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• 2018

Purpose: In this paper, based on this background, the main purpose of studying the behavior of concrete slab reinforced with new material fiber in impact loading is investigated by AFRP using aluminum fiber. Results: Research on the use of new materials as reinforcing materials for concrete members has been carried out in many fields such as flexural and shear tests under static loading, fatigue loading under cyclic loading, and application to PC beams. However, And the issue of plate elements is still at a basic stage. Conclusion: In this paper, the dynamic behavior of reinforced concrete slabs is investigated by using AFRP rod reinforced with aluminum fiber.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.734-737
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• 2004

The synthetic fibers such as polypropylene(PP) and polyvilyl-alcohol(PVA) fiber are poised as a low cost alternative for reinforcement in structural applications. It has been reported that synthetic fiber in cement composites can control restrained tensile stresses and cracks and increase toughness, resistance to impact, corrosion, fatigue and durability. High performance fiber reinforced cementitious composite(HPFRCCs) shows ultra high ductile behavior in the hardened state, because of the fiber bridging properties. Therefore, a variety of experiments have being performed to access the performance of HPFRCCs recently. The research emphasis is on the flexural behavior of HPFRCCs made in synthetic fibers, and how this affects the composite property, and ultimately its strain-hardening performance. Three-point bending tests on HPFECCs are carried out. As the result of the bending tests, HPFRCCs showed high flexural strength and ductility. HPFRCCs made in PVA or Hybrid fiber were, also, superior to PP of singleness. On the other hand, effect of sand volume fraction on HPFRCCs made in PP was insignificant.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• 제14권2호
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• pp.24-31
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• 2018

In this paper, specimen tests with simulated large seismic conditions have been carried out to investigate damage characteristics such as structural deformation and crack initiation under seismic loading. The mechanical behavior of the specimens is predicted by numerical simulations and the strain-based damage evaluations are performed. Finite element analyses of the specimens under the simulated seismic loading at room and operating temperatures were carried out for low alloy steel and stainless steel materials. Peak strain amplitude, cumulative fatigue damage and cumulative strain limit damage are calculated considering the nature of cyclic loading. In all cases, the allowable damage criteria are exceeded at the time of observing cracks visually in the tests. Therefore, it is confirmed that the material behavior due to the large seismic loads can be predicted by the numerical method and the structural damage of the materials can be evaluated conservatively based on the strain criteria.