• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.947-952
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• 2010

Components such as pressure vessel, hydraulic hose assembly, accumulator, hydraulic cylinder, hydraulic valve, pipe, etc., are tested under the impulse-pressure conditions prescribed in ISO and SAE standards. The impulse pressure test machine needs to have a high pressure, a precise control system and a long life. It should satisfy the requirements for fabrication of the impulse tester to generate ultra high pressure in the hydraulic system. In the impulse tester, a servo-valve control system is adopted; although the control application is convenient, it is expensive owing to the cost of developing the system. The type of the control system determines the pressure wave, which affects the components that are tested. In this study, the manufacturing process and the intensifier system design related to the flow, pressure, and the increasing rate of pressure are investigated. The results indicate the ultra high pressure waves in the system.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.2
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• pp.205-215
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• 2002

The purpose of this study was to identity the relationship of clothing involvement, consumer characteristics, and clothing buying behavior of college female students in China. A questionnaire was developed to measure clothing involvement, materialism, conspicuous consumption, reference group influence, clothing purchasing modes, fashion information sources. The questionnaire was administered to 390 college female students in Dandong of china. The data were analyzed using percentage, frequency, factor analysis, and t-test. The results of the study were as follows: 1. Subjects were divided into low clothing involved and high clothing involved groups according to the level of clothing involvement. 2. Three dimensions of materialism were derived by factor analysis such as Happiness-pursuing, Life-centered, and Sucess-symbolic. And three dimensions of conspicuous consumption and reference group influence were derived by factor analysis such as luxury oriented, Status symbolic, Brand-name oriented, and Comparative, Informational, Normative exactly. Clothing purchasing motives and fashion information sources were factor analysed as Social and Individual mole, and Printed & Electric-wave media, Marketer managed, Personal exactly. 3. There were significant differences between high involved and low involved consumers in consumer characteristics and clothing purchasing behavior. The high involved consumers showed more importance than low involved consumers about materialism especially in Happiness-pursuing about conspicuous consumption in status symbolic and about influence of reference group in comparative. The high involved consumers put more importance than low involved consumer individual motive as clothing purchasing motive, and marketer managed in clothing fashion information. The high invoked consumers showed more importance than low invoked consumers about evaluating attributes of product, and about store patronage criterion.

• The Journal of the Korean dental association
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• v.55 no.10
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• pp.688-694
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• 2017

Objectives: This preliminary study compared the effects of glide path establishing instruments prior to substantial root canal preparation. Materials and Methods: Glide path was established by enlargement of the 2nd mesiobuccal root canal of Dentalike by using three kinds of glide path preparation nickel-titanium file; PathFile, One G and ProGlider. The pre- and post-instrumented Dentalikes were weighed in the resolution of 1 / 10mg. In addition, after glide path preparation, torque generated during shaping using the WavoOne file was measured. The data were analyzed by one-way ANOVA and Tukey post-hoc test at a significance level of 95%. Results: The ProGlider had the significantly larger amount of reduced weight than other instrument groups (p < 0.05). There was no significant difference between group of glide path preparation with ProGlider and without glide path preparation in maximum torque and total stress generation during the shaping with WaveOne. Conclusions: Glide path preparation instruments may have different efficiency according to their geometries. The Dentalike artificial teeth were revealed to have discrepancies in the size of root canals by microCT examination. It is impossible to make a meaningful judgment of the results due to the reliability or resolution problem of the root canal size of the artificial tooth selected as the standardized tooth.

• Korean Journal of Human Ecology
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• v.20 no.2
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• pp.285-298
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• 2011

The purpose of this study was to analyze in detail the employment characteristics of the elderly over 65 years old and to compare those that have experienced no job change in the last 10 years with another group that have experienced job change at least once in the last 10 years. From the 10th wave data(KLIP), participants who were over 65 years old were chosen and their employment status for the last 10 years was reviewed. The results of this study were as follows: first, the analysis of demographic profiles indicated that householders and elderly couples with low education levels and low socioeconomic status were more likely to be employed compared to others. Second, in terms of work-related characteristics, it was revealed that the elderly who were employed tended to be non-paid workers, employers, and self-employed workers, primarily in the farming, fishing, forestry, and the mining industries, these were the elderly workers who had experienced job change three times or more in the last 10 years. Third, the analysis of economic characteristics indicated that elderly who were employed tended to rely more on private income transfers. Last, when the elderly who had experienced no job change in the last 10 years were compared to the elderly who had experienced job change in the last 10 years, the two groups differed significantly in terms of employment status, type of business, and occupation category.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.861-872
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• 1999

Since pathologic changes of exposed root surface inhibit cell attachment and new attachment of connective tissue have been made, many efforts were apply to change the exposed root surface condition. Scaling and root planing can not remove the endotoxin completely and forms the smear layer which prohibits the new attachment of connective tissue. Therefore, many kinds of chemicals were used for controlling the pathologic change of the root surface. The purposes of this study was to compare and observe the changes of the exposed root surface treated by scaling and root planning, Tetracycline HCl and Argon Laser. After the scaling and root planning of ten extracted premolars, the differences & the root surface among groups were observed under SEM. Control group showed smear layer and irregular amorphous surface. The dentinal tubule was not exposed. The debris and scale like texture were also observed. Tetracycline HCl treated group showed relatively smooth surface and the collagen fiber was observed in the dentinal tubule. Argon Laser treated group showed the most effective results under the conditions of 0.8 to 1.0w irradiation for 0.5 to 1.0 sec with pulse wave. The results of this study showed that the root surface change was associated with the intensity and the duration of Argon Laser irradiation. Further investigation for the surface change with the Argon Laser irradiation is recommended for understanding of clinical effect.

• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.82-89
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• 2012

Purpose: In this study, the effects of stability exercise, extracorporeal shock wave therapy, and taping on pain and function in patients with myofascial pain syndrome of upper trapezius were compared. Methods: The subjects were divided into the stability exercise, ESWT and the taping treatment group and the clinical outcomes were evaluated by visual analog scale (VAS), pressure pain threshold (PPT) and a constant-murley scale (CMS) at pre-treatment and post-treatment. Paired t-test and ANOVA was used for statistical analysis. Results: All groups were statistical significance in the change in visual analog scale (p<0.05). The difference between the ESWT group and taping group was statistical significance in the change in pressure pain threshold (p<0.05) except for the taping group. Using the constant-murley scale, the stability exercise group showed a significant decrease in pain, and a significant increase in ROM, ADL, strength, total score of shoulder (p<0.05); however, the ESWT group showed no difference on ADL. In addition, there was no difference in strength for the taping group. The comparison of the effect between the stability exercise group, ESWT group and taping group in CMS showed a statistical significant difference in pain, ADL and ROM (p<0.05). Conclusion: These results indicate that stability exercise, ESWT and taping could be considered an effective and efficient treatment modality for myofascial pain syndrome of upper trapezius.

• Journal of Chest Surgery
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• v.31 no.1
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• pp.7-12
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• 1998

The study in detection of perioperative myocardial infarction by serial ECGs and the analysis of risk factors involved was carried out from January 1994 to July 1996 on 87 consecutive patients undergoing coronary artery bypass grafting. There were significant differences in the mean CK-MB peaks and frequencies of flipping in LDH1/LDH2 among the 3 groups(group I: new Q-wave, group II: S-T change, group III: no ECG change). The ECG was considered positive for postoperative myocardial infarction if the new Q-waves appeared in the postoperative period or if S-T segment changes persisted for more than 48 hours. The hospital mortality rate was 3.3% and the perioperative infarction rate was 17.2%. The following risk factors of the perioperative MI were found: endarterectomy, decreased ejection fraction($\leq$40%) and prolonged aortic cross clamping time. Left main disease, triple vessel disease, 3 or more graft, unstable angina and hypertension did not correlate with myocardial infarction. This study suggests that serial ECGs could be used as means of detecting the perioperative myocardial infarction after coronary artery bypass grafting.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.351-360
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• 2003

This study was carried out to settle the plugging problem which occurs frequently when agricultural wettable powder is used in pest control work using the crushing and the dispersing effects caused by irradiation of ultrasonic wave. Sonication was applied to the wettable powder suspension in a beaker for 30 seconds using a 28 kHz, 200 W PZT BLT, and the image of suspension before and after sonication was observed using a microscope and a SEM. The image of tow commercial wettable powder suspensions in water observed using an optics microscope showed that the agglomerated particles were irregularly distributed over the whole observed region when stirred mechanically, while showing more uniform distribution composed of comparatively single particles in the whole observed region after sonication. Concerning the above, the projected areas of particles in the four suspensions after sonication were decreased distinctively in the observed range of the microscope and the atomization of crystals was much developed. Over the measured range of 5.6∼4,157 ${\mu}$m particle size, the overall projected area of particles was decreased to 58.3∼89.6% on the average after sonication. When the SEM images of sonicated wettable powder suspensions dissolved in water and CH$_3$OH were compared to the suspensions before sonication, such phenomena as the atomization of particles, the expansion of voids between particles, the reduction and the decrease of agglomerated particle groups, and the progress of crack developments on the surface of flake-shaped particles were observed. It seemed possible that the plugging problem that occurs frequently in pest control machine when using wettable powder would be settled by the use of sonication.

• Structural Engineering and Mechanics
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• v.43 no.5
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• pp.637-655
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• 2012

In this study, stochastic responses of a cable-stayed bridge subjected to the spatially varying earthquake ground motion are investigated by the finite element method taking into account soil-structure interaction (SSI) effects. The considered bridge in the analysis is Quincy Bay-view Bridge built on the Mississippi River in between 1983-1987 in Illinois, USA. The bridge is composed of two H-shaped concrete towers, double plane fan type cables and a composite concrete-steel girder deck. In order to determine the stochastic response of the bridge, a two-dimensional lumped masses model is considered. Incoherence, wave-passage and site response effects are taken into account for the spatially varying earthquake ground motion. Depending on variation in the earthquake motion, the response values of the cable-stayed bridge supported on firm, medium and soft foundation soil are obtained, separately. The effects of SSI on the stochastic response of the cable-stayed bridge are also investigated including foundation as a rigidly capped vertical pile groups. In this approach, piles closely grouped together beneath the towers are viewed as a single equivalent upright beam. The soil-pile interaction is linearly idealized as an upright beam on Winkler foundation model which is commonly used to study the response of single piles. A sufficient number of springs on the beam should be used along the length of the piles. The springs near the surface are usually the most important to characterize the response of the piles surrounded by the soil; thus a closer spacing may be used in that region. However, in generally springs are evenly spaced at about half the diameter of the pile. The results of the stochastic analysis with and without the SSI are compared each other while the bridge is under the sway of the spatially varying earthquake ground motion. Specifically, in case of rigid towers and soft soil condition, it is pointed out that the SSI should be significantly taken into account for the design of such bridges.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.439-452
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• 2018

This study aims to empirically structure the patterns of consumption and their effects on depression among the employed baby-boomers who were born in 1955 to in 1963. We used the 5th wave of Korea Retirement and Income Study(KReIS) in 2013 (n=2,585). The Latent Profile Analysis(LPA) estimated the empirical patterns of consumption and then a multiple regression analyzed the effect of consumption patterns on depression. The LPA results showed that the consumption patterns consist of four groups: Basic life-oriented class, Social life-oriented class, Home-based lifestyle class, and Advanced consumption-oriented class. The working baby boomers' depression was associated with their consumption patterns. Specifically, the social life-oriented class showed significantly lower depression than the basic life-oriented class and advanced consumption-oriented class. Other associates with higher levels of depression were found as lower education, having no spouse, lower self-rated health, higher levels of physical limitation, having a diagnosed disability, lower satisfaction with leisure activities, lower income, and lower subjective economic status in this study. Based on the results of this study, we propose the need for specialized financial intervention better for baby-boomers' retirement preparation in Korea.