• Membrane and Water Treatment
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• 제10권2호
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• pp.113-120
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• 2019

To investigate surface properties and interception performances of the new modified PVDF membrane coated with Graphene Oxide (GO) and nano-$TiO_2$ (for short the modified membrane) via the interface polymerization method combined with the pumping suction filtration way, filtration experiments of the modified membrane on Humic Acid (HA) were conducted. Results showed that the contact angle (characterizing the hydrophilicity) of the modified membrane decreased from $80.6{\pm}1.8^{\circ}$ to $38.6{\pm}1.2^{\circ}$. The F element of PVDF membrane surface decreased from 60.91% to 17.79% after covered with GO and $TiO_2$. O/C element mass ratio has a fivefold increase, the percentage of O element on the modified membrane surface increased from 3.83 wt% to 20.87%. The modified membrane surface was packed with hydrophilic polar groups (like -COOH, -OH, C-O, C=O, N-H) and a functional hydrophilic GO-polyamide-$TiO_2$ composite configuration. This configuration provided a rigid network structure for the firm attachment of GO and $TiO_2$ on the surface of the membrane and for a higher flux as well. The total flux attenuation rate of the modified membrane decreased to 35.6% while 51.2% for the original one. The irreversible attenuation rate has dropped 71%. The static interception amount of HA on the modified membrane was $158.6mg/m^2$, a half of that of the original one ($295.0mg/m^2$). The flux recovery rate was increased by 50%. The interception rate of the modified membrane on HA increased by 12% approximately and its filtration cycle was 2-3 times of that of the original membrane.

• 한국시뮬레이션학회논문지
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• 제29권1호
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• pp.1-9
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• 2020

과학기술의 발전에 따라 탄도탄에 대한 위협이 나날이 증대되고 있으며, 이러한 위협에 대처하기 위한 탄도탄 요격미사일에 대한 개발이 요구되고 있다. 대탄도탄용 요격미사일의 개발을 위해서는 요격시험이 필수적이다. 시험을 통해 얻은 계측자료를 활용하여 요격미사일을 포함한 전체적인 요격 시스템의 성능을 확인할 수 있다. 그러나 요격시험 시에는 요격에 의한 파편이 발생되기 때문에 안전을 위한 민간인의 접근 통제가 필요하다. 따라서 요격시험에 앞서 요격 파편에 대한 안전구역의 신뢰도 높은 추정이 선행되어야 한다. 본 논문에서는 모델링 분석 및 시뮬레이션을 활용하여 요격 파편에 대한 안전구역을 산출하였다. 우선, 탄도탄과 요격미사일의 발사단계에서 요격까지의 전 과정에 대한 시뮬레이션을 수행하였고, 요격 시점에서의 상대 속도 및 상대 각도를 산출하였다. 이 결과를 활용하여 요격 시의 에너지를 계산하고 요격 파편의 방출속도를 산출하였다. 이후, 파편에 작용하는 항력과 중력을 고려하여 낙하 궤적을 산출하였고, 파편의 낙하 지점과 위험도를 종합적으로 고려하여 최종 안전구역을 산출하였다.

• 가정과삶의질연구
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• 제27권5호
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• pp.77-90
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• 2009

The purpose of this study was to investigate the residents' use and occupancy-behavior in the activity areas of the senior nursing facilities, and to provide basic information to establish the appropriate physical elements for planning the activity areas. For the study, the observations in five facilities were conducted for one day, from 10 a.m. to 4 p.m by four researchers. The results of the study are summarized as follows: First, most of the using behaviors in the activity areas were the doing nothing or sleeping. The meals and program services were provided in only one activity area of the floor and it showed that the unit care system was perfunctorily conducted at those facilities. In the representative activity area, its openness was the main physical element influencing the spatial using frequency, while the accessibility and the openness in the sub-activity area were most important. The seating arrangements having comers were helpful for residents' interactions. Second, while facility programs and meals were provided in the specific activity area, there was no residents' occupancy in other activity areas at the same time. There were interactions including residents' conversations and watching/observations in non-designated activity areas such as the nursing stations and near corridors. But the residents' interactions and self-regulations were blocked by absence of territoriality, monotonous spatial compositions and furniture arrangements, insecurity of residents' privacy, wide or narrow areas, and isolated spatial type. Based on the results at the above, basic guidelines for planning the activity areas of senior nursing facilities can be proposed as follows: First, the isolated type and the sight interception should be avoided in representative activity areas. It should be partitioned with couple of areas through the appropriate furniture arrangements, and be prepared semi-private spaces in non-designated areas such as nursing station for the interactions among the residents and the staff. Second, in activity areas for small group, the isolated type is not also good for the residents' accessibility. The residents' privacy should be confirmed through the various spatial compositions, and enough areas need to be sure for the diverse furniture arrangements.