• Journal of Applied Reliability
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• v.15 no.4
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• pp.270-275
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• 2015

Purpose : UHMWPE (Ultra-high-molecular-weight-polyethylene) is one of the most widely used material in knife protection clothes because of high strength, elasticity, and light weight. The purpose of this study is to develop the accelerated life test method and predict the lifetime for the knife protection fabric composed by UHMWPE. Methods : In this study, degradation characteristics of UHMWPE fibers and knife protection fabric for cut resistance were evaluated under the hydrolysis and photo-degradation conditions. It was found out that the degradation rate of retained tensile strength was more significant in the photo-degradation than hydrolysis. Therefore, the failure time was determined as the time that the retained tensile strength in photo-degradation is less than 50%. Considering an acceleration factor for irradiance and exposure time, the lifetime was predicted from the calculated failure time. Results : As a result of the accelerated life test, the $B_{10}$ lifetime of knife protection fabric composed by UHMWPE fibers is estimated as 2.8 years for a 90% statistical confidence level. Conclusion: Since the lifetime is predicted by the view-point of radiant exposure in this study, there is a possibility that the estimated lifetime may differ from the actual lifetime. However, it is considered as an useful methodology to estimate the long-term lifetime of knife protection fabrics.

• Journal of Korean Academy of Nursing
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• v.25 no.1
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• pp.110-123
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• 1995

This study was done to analyze the relationship between task stress and morale in psychiatric nursing assistants. The subjects were 118 psychiatric nursing assistants selected from the National Mental Hospital in Seoul and 18 non-medical mental institutions. The data were collected from October 22 to November 12, 1994. The instruments used for this study were modified PNOSS (Psychiatric Nurse Occupational Stress Scale) which was developed by Bai and modified the Morale scale which was developed by Oh. The confidence varification of these instruments were computed and Cronbach $\alpha$=.9255, .9260. Data were analyzed by t -test, ANOVA on 5% significant level and Pearson correlation coefficient. The results of the study are as follows : 1. The average work stress scores of subjects were 2.83. Among the work stress factors : the conflict with nurse was identified as the most stress factor. There was significant relationship between the degree of work stress and the variables of psychiatric Nursing Assistants such as the marital status, educational level, religion, job satisfaction, working place, predicted period of work. 2. Average total morale scores for the subjects was 3.08. There was a significant relationship between the degree of morale and variables of psychiatric nursing assistants such as working place, certification as a nursing assistant, job satisfaction, opportunity for practical education and predicted period of work. 3. There was a significant relationship between the degree of morale and work stress factors such as administration problem, work overload.

• Journal of the Korean Society of Costume
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• v.52 no.5
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• pp.15-30
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• 2002

The purposes of this study were to identify the Chinese university students' clothing attitudes and purchasing behavior according to their lifestyle. Questionnaires developed by researcher were distributed and collected from 540 Chinese university students from Mar. 5 to Mar. 20, 2001. Means, frequencies, and percentages were calculated. Factor analysis, cluster analysis. one-way ANOVA, and Chi-square test were used for data analysis. And Duncan's multiple range test was followed. The factors of lifestyle were consumption, self-confidence, economy, accomplishment. sociability. fashionability, individuality, and conservation. Chinese university students were segmented into 4 groups of the modern sociable, the passive stagnated, the positive progresive, and the traditional conservative. The group size of the modem sociable was the smallest, and the traditional conservative was the largest. Chinese university students considered sexual attractiveness of clothing most important. Psychological dependence and ostentation of clothing were next important in a decending order. The passive stagnated considered conformity of clothing most important and showed the opposite tendency of the modern socialable. The positive progressive considered all aspects of clothing attitudes important, and showed the opposite tendency of the traditional conservative. Chinese university students utilized direct fashion information sources, and patronized medium or small size department store or traditional market.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.72-78
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• 2016

In this study, we analyzed the accidental hydrogen embrittlement affecting the track nut on a self-propelled howitzer. Tracks are key components to maintain a high degree of confidence in the operation of the self-propelled howitzer and the safety of the crew. This study analyzed the fractured surface using SEM to review accidental damage of the wedge nut. In addition, we conducted revival tests and analyzed the results to identify the cause of the wedge nut damage from hydrogen embrittlement. We should carry out factor analysis and continuous improvement of the manufacturing process to determine the accidental breakage mechanism for future enhancement of the self-propelled howitzer. This study will be the useful reference for enhancing process designs in similar products.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.689-697
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• 2005

This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, $B_{10}$ life and its lower bound with $90\%$ confidence at worst case use condition are estimated by analyzing the accelerated life test data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.8 s.101
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• pp.988-995
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• 2005

Vibration has been severly increased at the branch pipe of main steam header since the commercial operation of nuclear power plant. Intense broad band disturbance flow at the discontinuous region such as elbow, valve, and header generates the acoustical pulsation which is propagated through the piping system. The pulsation becomes the source of low frequency vibration at piping system. If it coincide with natural frequency of the pipe system, excessive vibration is made. High level vibration due to the pressure pulsation related to high dynamic stress, and ultimately, to failure probability affects fatally the reliability and confidence of plant piping system. This paper discusses vibration effect for the branch pipe system due to acoustical pulsations by broad band disturbance flow at the large main steam header in 700 MW nuclear power plant. The exciting sources and response of the piping system are investigated by using on-site measurements and analytical approaches. It is identified that excessive vibration is caused by acoustical pulsations of 1.3 Hz, 4.4 Hz and 6.6 Hz transmitted from main steam balance header, which are coincided with fundamental natural frequencies of the piping structure. The energy absorbing restraints with additional stiffness and damping factor were installed to reduce excessive vibration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1672-1677
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• 2005

The Heat exchanger to be used in the place of business that is presented an utility period comes to be long and the problem of the length of life shares by the manufacture course and using environment factor. Consequentl, it is came to the front problem of inspection, repair, exchange, the utility stopping, safety and confidence. As a result the possibility which the large safety accident can happen comes to be high. It leads mostly to the large accedent when the explosion accident happens. to keep this, The system which the regular period passes to disuse the structure is prepared but The phenomenon which Time and the strength characteristic of the material change, namely Deradation. but It can't be a preventable solution by accident to the damage. Consequentl, This research can take important role to prevent an every kind accident for domestic pressure vessel by evaluating the mechnical characteristic change of meterial, the structure safety and residual life etc.

• The Korean Journal of Community Living Science
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• v.21 no.2
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• pp.191-200
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• 2010

The purpose of this study was to research the differences between gender roles and creativity. This study was done based on 178 pre-service teachers who were from the Department of Early Childhood Education in Universities around the Busan area. The researchers have collected statistical data by questioning pre-service teachers about creative thinking tests, creative personality tests, and gender role identification awareness tests. The data was interpreted by the Paerson's Simple Product-moment Correlation Coefficient method, the one-way ANOVA method, and the $Sch\acute{e}ffe$ Post-hoc comparison method. According to this study, the group perceived of high androgyny type group showed the highest level in important factors of creative thinking, such as fluency, elaborateness, ness, and openness. This result meant that the more a pre-service teacher was aware of the identity of gender roles, the more she or he thought creatively. Additionally, the acceptance of authority, an element of the creative personality factor, showed the highest level in a high feminity type group. On the other hand, self confidence, inquisitiveness, and disciplined imagination showed the highest level in a group which perceived the identity of androgyny type roles.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.955-965
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• 2014

Transport phenomena of reactant and product are directly linked to intrinsic inhomogeneous random configurations of catalyst layer (CL) that consist of ionomer, carbon-supported catalyst (Pt/C), and pores. Hence, electrochemically active surface area (ECSA) of Pt/C is dominated by geometrical morphology of mass transport path. Undoubtedly these ECSAs are key factor of total fuel cell efficiency. In this study, non-deterministic micro-scale CLs were randomly generated by Monte Carlo method and implemented with the percolation process. To ensure valid inference about Pt/C catalyst utilization, 600 samples were chosen as the number of necessary samples with 95% confidence level. Statistic results of 600 samples generated under particular condition (20vol% Pt/C, 30vol% ionomer, 50vol% pore, and 20nm particle diameter) reveal only 18.2%~81.0% of Pt/C can construct ECSAs with mean value of 53.8%. This study indicates that the catalyst utilization in fuel cell CLs cannot be identical notwithstanding the same design condition.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.1
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• pp.57-70
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• 1995

The purpose of this study was to identify clothing behavior of elderly women and compare the clothing behavior by different types of lifestyle among females aged 50~69. A questionnaire was developed to measure the clothing behavior, lifestyle and demographic characteristics. The questionnaire was administered to 445 females aged 50~69 during february and May of 1994. Data were analyzed by using factor analysis, cluster analysis, ann MANOVA. The results of this study were as follows; 1. The lifestyle factors were derived: they were Economics oriented, Leisure oriented, Traditional family oriented, Consumption oriented, Self-confidence oriented, and Independence oriented. The respondents were categorized into five groups such as Conservatives, Independents, Pleasure seekers, Positivists, and Material seekers. 2. Symbolism, interest, aesthetics and management showed significant differences in different lifestyle groups. 3. Comfort, modesty, and approval showed significant differences in age and family lifestage. Dependence, management, comfort, modesty, and approval showed significant differences in marital status. Aesthetics, comfort, dependence, interest, modesty, and symbolism showed significant differences in educational level and the money they can spend on clothes in one month.