• 수산해양교육연구
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• 제28권3호
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• pp.881-892
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• 2016

The objective of this research is significant because it derives the core competency factors that members of education communities must have in order to form warm education communities through investigating the perception of special education teachers. To achieve this, 352 special education teachers and teachers working at special education institutes were asked to record three of the most important factors out of a total of 18 factors that members of an educational community considered to be required in order to form warm educational communities. IBM SPSS Statistics 23 was used to analyze the collected data. First, in oder to examine the demographic characteristics of the educators surveyed, frequency analysis was conducted. Second, frequency analysis on the factors that special education teachers considered to be most important to form a warm education communities was conducted by teacher experience and type of education institute they worked for. When analyzing the research results of main factors that special education teachers considered to be important by teacher experience and type of education institute they worked for, responsibility was confirmed to be the most important factor. The second most important factor was communication and the third most important factor was responsibility and trust. In summary, the research confirmed that if mutual trust between the members of an education community can be established and if problems can be solved through cooperation and through open communication, and if each member of the community serves their role responsibly, a warm education community can be formed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 춘계학술대회논문집
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• pp.45-52
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• 1998

This study is to investigate the effects of warm deep drawing with aluminum sheets of A1050-H16 and A5052-H32 for improving deep drawability. Experiments for procucing circular cups and square cups were carried out for various working conditions, such as forming temperature and blank shape. The limit drawing ratio(LDR) of 2.63 in warm deep drawing of circular cups in case of A5052-H32 sheet, whereas LDR of A1050-H16 is 2.25, could be obtained and the former was 8 times higher than the value at room temperature. The maximum relative drawing depth for square cups of A5052-H32 material was also about 2 times deeper than the depth drawn at room temperature. The effects of blank shape, and temperature on drawability of aluminum materials as well as thickness distribution of drawn cups were examined and discussed.

• 열처리공학회지
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• 제10권2호
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• pp.81-92
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• 1997

The effect of alloying elements, precipitate size, its distribution, and dislocation substructure resulted from warm rolling or cold rolling in the superplastic Al-Mg alloy system was investigated. One of the major requirements for fine structure superplasticity is that the grain size should be very small. Fine grain structure is controlled by the dislocation substructure and the dynamic recrystallization during hot or warm working. The recovery of Al-Mg base alloys was constrained resulting in relatively high dislocation density when the alloys were warm rolled. In particular, Al-Mg-Zr alloy exhibited the smallest sub-grain size among Al-Mg alloys containing Mn, Cu, Zr as a third element. The Al-Mg-Mn alloy cold rolled 80% after hot rolling showed the maximun strain rate sensitivity exponent, m, of 0.75 under strain rate of $7.1{\times}10^{-4}/s$ at $500^{\circ}C$. The elongation of the alloys was limited in spite of high m values due to large dispersoids containing appreciable amount of Fe impurities.

• 한국초전도ㆍ저온공학회논문지
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• 제14권3호
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• pp.48-52
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• 2012

This paper describes experimental study on the orientation dependence of GM-type pulse tube refrigerator with helium and neon as working gas. A pulse tube refrigerator generates refrigeration work with gas expansion by gas displacer in the pulse tube. The pulse tube is only filled with working gas and there exists secondary flow due to large temperature difference between cold-end and warm-end. The stability of secondary flow is affected by orientation of cold-head and thus cooling performance is deteriorated by gas mixing due to secondary flow. In this study, a single stage GM-type pulse tube with orifice valve as a phase control device is fabricated and tested. The fabricated pulse tube refrigerator is tested with two different working gases of helium and neon. First, optimal valve opening and operating frequency are determined with experimental results of no-load test. And then, the variation of no-load temperature as orientation angle of cold-head is measured for two different working gases. Effect of orientation dependence of cold-head as working gas is discussed with experimental results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.198-201
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• 2004

Aluminum alloys have high potential for weight reduction in automotive and other applications. But aluminum alloys have relatively low tubular hydroformability which can be enhanced by conducting the hydroforming at elevated temperatures. Hot working processes are commonly used in bulk forming such as forging and rolling, but still is rare in sheet metal forming like hydroforming. In this study hydroforming test at elevated temperatures is performed by special designed induction heating system to investigate the hydroformability of aluminum alloys. The high temperature formability characteristrics are obtained by 1?fitting forming test and circular bulging test and the effects of the process parameters such as feeding amount, internal pressure and temperatures on the tubular forming limits are mainly investigated.

• 대한가정학회지
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• 제38권6호
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• pp.135-147
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• 2000

The purpose of the study was to investigate the effects of economic hardship. parents'intro-eatrovert personality, and depression on parenting. The subjects were 487 seventh to ninth grade children and their parents. Data were collected through questionnaires. Children from which family experienced severe income loss perceived fathers'child-rearing attitudes as more warm/nurturant when fathers had extrovert personality. On the other hand, children under the worse paternal working condition perceived mothers'child-rearing attitudes as more warm/nurturant when mothers had introvert personality. The impacts of family income loss on mothers'rejecting/inconsistant child-rearing attitudes were exacerbated by its indirect effect through maternal depression.

• Journal of Advanced Marine Engineering and Technology
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• 제36권8호
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• pp.1151-1157
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• 2012

OTEC기술은 신재생에너지 기술 중의 하나로 따듯한 표층수와 차가운 심층수의 온도차를 이용하여 전력을 생산하는 기술이다. 작동유체의 선정과 OTEC 사이클의 상태에 따라 에너지효율과 환경적인 측면에 많은 영향을 준다. OTEC의 작동유체로는 ammonia, R22, R407C, R410A가 있다. 본 논문에서는 OTEC 시스템의 최적화를 위해 $25^{\circ}C$에서의 증발압력를 비교하였다. 또한 밀폐사이클과 재생사이클에서의 작동유체에 따른 출력과 효율에 대하여 연구하였다.

• 가정과삶의질연구
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• 제16권4호
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• pp.1-16
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• 1998

this study examined the correlates of adult attachment focused on internal working models of 201 housewives. Findings indicated that 68.3% of subjects were classified as secure whereas 27.5% as avoidant and 4.2% as anxious. Greater security was associated with slightly less avoidance while greater anxiousness was associated with slightly greater avoidance. That is subjects who possessed more security tended to be less avoidant while subjects who possessed more anxiousness tended to be more avoidant. The primary characteristics classifying subjects into those three attachment styles were feelings about closeness dependence and anxiousness in relationships with others. Adult attachment was related in theoretically expected ways to one's history of attachment and parenting. Secure subjects were more likely to report warm/responsive parental caregiving style than insecure styles. Insecure subjects in comparison with secure subjects perceived their mothers as cold inconsistent and ot very responsive. Anxious subjects dscribed their fathers as cold and rejecting. The secure attachment style in comparsion with insecure styles was associated with positive mental models of self and social world indicating greater self-esteem positive beliefs about self and others positive relationships with their children greater marital satisfaction and greater secure attachment to their husbands. These results suggest that internal working model offers a useful perspective on adult attachment.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권5호
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• pp.568-576
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• 2017

With an increase in the usage of LNG, there is a heightened interest about its safety aspects regarding the explosion of LNG carrier tank. The need for a cryogenic explosion-proof camera has increased. The camera has to work in cryogenic environment (below $-160^{\circ}C$) in LNG carrier. This study conducted design and heat transfer analysis of cryogenic camera to secure working time in limitation of heat source. The design with gap width of double pane windows was conducted based on simple vertical cavity model to insulate from cryogenic environment. The optimal gap width was 12.5 mm. For effective analysis considering convection within the camera, equivalent thermal conductivity method was adopted with ABAQUS. The working time of the camera predicted was over 10 h at warm-start condition. In cold-start condition, it required about 5 h of pre-warming time to work. The results of analysis were compared with the ones of the actual cryogenic test.

• 소성∙가공
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• 제12권8호
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• pp.710-717
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• 2003

The implicit, finite element analysis program for analyzing the springback in the warm forming process of aluminum alloy sheets was developed. For the description of planar anisotropy in warm forming temperatures, Barlat's yield function is employed, and the power law type constitutive equation is used in terms of working temperatures for the depiction of work hardening in high temperatures. Also, Jetture's 4-node shell elements are introduced for reflecting the mechanical behavior of aluminum alloy sheet and the non-steady heat balance equations are solved for considering heat gain and loss during the forming process. For the springback evaluation, Newton-Raphson iteration method is introduced for overcoming the geometric nonlinearlity problem. In order to verify the validity of the FEM program developed, the stretching bending and springback processes are simulated. Though springback analysis results are slightly bigger than experimental ones, they have the same trend of the decreasing springback as the forming temperature increases.