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A Study on the Shielding Ability of Current Aerospace Materials
우종관,Sue Lynn Lee,Dong LIU 한국물리학회 2019 새물리 Vol.69 No.2
Space radiation is one of the biggest concerns for manned spaceflights, and along with the swift development of spaceflight enterprises, research on materials to be use as shields against space radiation has become increasingly important. In this study, we summarize the major composition of space radiation and define the human phantom scoring volume, the shielding materials and the geometry of shielding structure. Then, we comprehensively consider the radiation shielding properties of various materials, together with a consideration of the mass problems associated with those shielding materials. The radiation shielding ability of materials against certain space radiation particles was appraised from the perspectives of radiation dose. The results showed for shielding materials that of about the same mass, employing composites and non-metal materials as shielding materials rather than metals or alloys was more advantageous. In addition, in practical applications, the cabin walls of spaceships usually consist of multiple layers. In this situation, cabin wall that combines high-density layers and low-density layers alternately has the optimal shielding effect.
사회경제적 지위가 청소년의 건강증진행동에 미치는 영향: 가족활동의 매개효과
김수린 ( Sue Lynn Kim ),이상균 ( Sang Gyun Lee ),유조안 ( Joan P Yoo ) 한국가족복지학회 2015 한국가족복지학 Vol.20 No.2
Although adolescents of low socioeconomic status (SES) are known to engage in healthpromoting behaviors (HPB) less frequently, the specific mechanism between their SES and HPB has not been extensively studied. This study assumed that family-based activities play a critical role, and are closely related to the double poverty of time and income caused by low SES, while providing adolescents with opportunities to establish desirable health behaviors. Accordingly, the mediating effect of family-based activities on the association between SES and HPB was examined. 636 adolescents and their parents from the 1st year survey of the Seoul Education & Health Welfare Panel (2014) were analyzed utilizing SEM. The results of the analysis show that adolescents of low SES engage in HPB less frequently. This association was partially mediated by family-based activities. Based on the findings, we suggest that enhancing education programs on HPB in schools and related community organizations may supplement the deficient family activities of low-SES families. The present finding encourages intervention that raises parents`` awareness about the importance of family-based activities on children``s HPB. Moreover, family-friendly environments promoting various family activities need to be emphasized to increase adolescents`` HPB.