• Steel and Composite Structures
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• 제4권1호
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• pp.1-8
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• 2004

Tests on steel tubular columns of square, rectangular and circular section filled with normal and lightweight aggregate concrete were conducted to investigate the failure modes of such composite columns. Thirty-six full scale columns filled with lightweight and normal weight aggregate concrete, eighteen specimens for each, were tested under axial loads. Nine hollow steel sections of similar specimens were also tested and results were compared to those of filled sections. The test results were illustrated by a number of load-deflection and axial deformation curves. The results showed that both types of filled columns failed due to overall buckling, while hollow steel columns failed due to bulging at their ends (local buckling). According to the above-mentioned results, and due to low specific gravity and thermal conductivity of the lightweight concrete the further interest should be concentrated in replacing the normal concrete by the lightweight aggregate concrete.

• 한국자동차공학회논문집
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• 제17권3호
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• pp.15-21
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• 2009

The anisotropic mechanical properties were measured for the three orthogonal orientations of plain weave glass fabric reinforced epoxy resin laminate. In tensile and flexural tests, axial and edge type specimens failed by pull-out of warp and fill yarns, respectively. In contrast, the thickness type specimens failed by adhesive failure process. Longitudinal cracking occurred in several of the edge type specimens during tensile test. That cracking caused pop-in in the stress-strain curve. Defects induced by improper coupon machining caused that cracking.

• 품질경영학회지
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• 제32권4호
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• pp.208-219
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• 2004

This paper considers a nonparametric estimation of lifetime distribution for ramp stress tests with stress bound under intermittent inspection. The test items are inspected only at specified time points an⊂1 so the collected observations are grouped data. Under the cumulative exposure model, two nonparametric estimation methods of estimating the lifetime distribution at use condition stress are proposed for the situation which the time transformation function relating stress to lifetime is a type of the inverse power law. Each of items is initially put on test under ramp stress and then survivors are put on test under constant stress, where all failures in the Inspection interval are assumed to occur at the midi)oint or the endpoint of that interval. Two proposed estimators of quantile from grouped data consisting of the number of items failed in each inspection interval are numerically compared with the maximum likelihood estimator(MLE) based on Weibull distribution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.336-338
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• 2006

Diagnostic tests are used to evaluate the insulation condition of stator windings in traction motor. These tests included ac current, tan delta and maximum partial discharge. The insulation condition of stator windings was assessed by three test items. The stator windings of traction motor were m good condition. After completing the diagnostic tests, the stator windings of traction motors were subjected to gradually increasing ac voltage, until the insulation punctured. No.5 stator windings failed near rated voltage of 18.9 kV. The breakdown voltage of No.1 stator windings was 13.0. The failure was located m a line-end coil at the exit from the core slot.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.92-97
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• 2003

Roadbed failure due to the rainfall may bring out social and economic demage such as the loss of life and property, the consumption of time and cost for recovery, and the delay of logistics in railway. In this study, the method using Geotextile Container was applied to rehabilitation of the railway roadbed which was failed by rainfall. The real scale tests with the simulated train loading were performed in order to evaluate the dynamic performance at the railway roadbed using Geotextile Container. The results of these tests were compared with unreinforced and reinforced cases with Geotextile Container, respectively. The data gathered by various measurement devices from these real scale tests would be useful to evaluate and understand the roadbed with Geotextile Container. Furthermore, the results of this study would be useful to ensure the workability and to save much time for restoration and to be widely applied to practical use.

• 보건교육건강증진학회지
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• 제21권1호
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• pp.137-151
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• 2004

Objectives： This study aims to investigate the psychological factors associated with abstention following a smoking cessation program, and to suggest useful information for those who want to stop . smoking and health practitioners who help them Methods： Participants were 73 smokers (65 males, 8 females) that participated in a hospitalized smoking cessation program, whose mean age was 44.89 (SD＝9.61). Participants completed questionnaires and psychological tests including： Demographic sheet, Eysenck's Personality Questionnaire, Multidimensional Coping Scale, Fagerstrom Test for Nicotine Dependence, and Jerusalem and Schwarzer's Self-Efficacy Scale. To identify whether the subjects abstained or not and to encourage them to abstain, the researcher called them on the telephone once a week for three months. After three months, they were contacted every other week till six months passed since they had left the smoking cessation program Tthey were THEN contacted once a month for another six months. The data was analyzed by using ANCOVAs with SPSS 10.0 for Windows. Results： 42 (57.5％) out of 73 abstained for one month and 26 (35.6％) abstained for one year. People who failed to abstain within a month showed a higher psychoticism and introversion personality trait than those who abstained for one month, while people who abstained for one month were coping actively in most situations, showed a higher self-efficacy and lower nicotine dependence than those who failed to abstain within a month, and people who failed to abstain within a year showed a higher psychoticism than those who abstained for one year. While people who abstained for one year were coping actively, obstinate, and interpreting positively most situations, they showed a higher self-efficacy than those who failed to abstain within a year. Conclusion： These findings reiterate the roles of personality, self-esteem, nicotine dependence in smoking and suggest the roles for smoking cessation. And it was found the roles of coping styles ,in smoking cessation. It might help smokers who want to stop smoking and health practitioners who help them

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.46-50
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• 2005

Smart skin, a multi-layer structure of composed of a round shape antenna, was designed and fabricated. Tests and analyses was conducted to study its behavior under compressive loads. It was confirmed that the designed smart skin failed due to premature buckling before compression failure. Numerical prediction of structural behavior of smart skin by MSC.NASTRAN agreed well with experimental data.

• 영어어문교육
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• 제11권4호
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• pp.139-166
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• 2005

The aim of this study was to examine the effects of remedial instruction on self-efficacy improvement in elementary school students with low self-efficacy, which may have been formed through negative experience with learning such as poor performance and poor grades. Nine 6th grade students with low self-efficacy were selected for the present study. A remedial class was set up and instruction was given once a week for 14 weeks. The purpose of the remedial class was to give the students a positive experience with English learning and have students reflect on their achievement. The contents and class activities were adjusted to the subjects' English abilities and also closely related to those of the regular classes so that students could have more confidence during regular English classes. The data were collected from a test of self-efficacy in English learning, achievement tests given before and after the experiment, achievement tests after each lesson, a general self-efficacy test, a basic questionnaire, interviews, journals, and students' self-evaluation. The results showed that the remedial instruction was very successful in providing students with a sense of achievement and improving students' self-efficacy in English learning. However, this study failed to find significant improvement in general self-efficacy tests and achievement tests given before and after the experiments. A longer period of remedial instruction may have been necessary to obtain more concrete results from the variety of data collected.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.924-932
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• 2004

In this study, the axial collapse tests were performed under either static (or quasi-static) or impact loads with several collapse velocities based on the expectation that para-closed sections of the front-end side members (spot welded hat and double hat shaped section members) would show quite different collapse characteristics from those for seamless section. The test results showed that both of the hat and double hat shaped section members failed in the stable sequential collapse mode in the static or quasi-static collapse tests, while the double hat shaped section members underwent the unstable collapse mode especially when the impact velocity is high. The mean collapse loads in the hat shaped section members increase with collapse velocity for all the cases of the static, quasi-static, and impact collapse tests. In the double hat shaped section members, however, the mean collapse loads decrease with increase in collapse velocity in the impact tests.

• 한국전기전자재료학회논문지
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• 제25권4호
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• pp.309-314
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• 2012

To assess the condition of stator insulation, nondestructive and overpotential tests were performed on four high voltage motors. The stator windings under these tests have nominal ratings of 6.6 kV. After completing nondestructive tests, the AC overvoltage applied to the stator windings was gradually increasing until insulation failure in order to obtain the breakdown voltage. No. 1, No. 2, No. 3 and No. 4 of 6.6 kV motors failed near rated voltage of 18.4 kV, 19.8 kV, 19.7 kV and 21.7 kV, respectively. The breakdown voltage of four motors was higher that expected for good quality coils(14.2 kV) in 6.6 kV motors. Almost all of failures were located in a line-end coil at the exit from the core slot. The breakdown voltages and the types of defects showed strong relation to the stator insulation tests such as in the case of AC current, dissipation factor($tan{\delta}$) and partial discharge magnitude.