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유연탄 bottom ash의 경량 및 단열 특성 (Characteristics of Lightweight and Thermal Insulation of Bituminous Coal Bottom Ash)

  • 이종규;여운호
    • 유기물자원화
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    • 제26권1호
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    • pp.39-45
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    • 2018
  • FA(Fly ash)에 대해서는 연구가 활발히 진행되는 반면 BA(Bottom ash)의 연구실적은 많지 않으며, 특히 BA 재활용 분야의 연구가 절실히 요구된다. 따라서 본 연구에서 다공성인 건식(공랭식) BA를 연구대상으로 선택해 이를 재료로 활용하여 만든 BA 모르터와 일반 모르터를 비교 분석하여 BA 모르터의 경량 및 단열 특성을 알아보고자 하였다. BA의 경량성을 알아보기 위해 밀도 시험, 단위용적질량 시험, SEM 시험을 하였으며, 단열 시험을 위해 BA 모르터와 일반 모르터 몰드를 KS A 0006에서 정한 상온 상습의 환경조건에서 제작 후 항량이 될 때까지 온도 $105{\pm}2^{\circ}C$에서 건조하였다. 경량성 시험 결과 BA 모르터의 경량성은 일반 모르터의 0.72배로 일반 모르터에 비해 약 30%정도 가볍게 측정되어 BA를 건축물 재료로 활용할 경우 건축물 하중을 줄이는데 크게 기여할 것이다. 또한 단열 시험 결과 BA 모르터의 열전도율은 일반 모르터의 0.70배로 약 30%정도 단열성이 우수하다.

A Series of 3D Lanthanide Complexes Containing (La(III), Sm(III) and Gd(III)) Metal-organic Frameworks: Synthesis, Structure, Characterization and Their Luminescent Properties

  • Zhang, Huai-Min;Yang, Hao;Wu, Lan-Zhi;Song, Shuang;Yang, Li-Rong
    • Bulletin of the Korean Chemical Society
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    • 제33권11호
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    • pp.3777-3787
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    • 2012
  • Three kinds of 3D isomorphous and isostructural coordination polymers, namely, $\{[Ln_2(PDA)_3(H_2O)_3]{\cdot}0.25H_2O\}_{\infty}$ (Ln = La(1), Sm(2), and Gd(3)) ($PDA^{2-}$ = pyridine-2,6-dicarboxylate anion) have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, thermal analyses and single crystal X-ray diffraction. In these MOFs, Ln(III) centers adopt eight-coordinated and nine-coordinated with the $N_1O_7$ and $N_2O_7$ donor sets to construct distorted trianglar dodecahedron geometry and tricapped trigonal prism configurations, respectively. Based on the building block of tetranuclear homometallic $Ln_4C_4O_8$ unit (16-membered ring), 1-3 are connected into highly ordered 2D sheets via O-C-O linkers and further constructed into 3D architectures through hydrogen bonds. Crystallographic parameters suggest that the lanthanide contraction effect exist in these coordination polymers. Luminescent properties of the lanthanide-based MOFs (metal-organic frameworks) have been measured at room temperature, which reveal that they presenting ionselective characters toward certain metals, such as $Mg^{2+}$, $Cd^{2+}$ and $Pb^{2+}$ ions.

Diagnostic reference levels in intraoral dental radiography in Korea

  • Kim, Eun-Kyung;Han, Won-Jeong;Choi, Jin-Woo;Jung, Yun-Hoa;Yoon, Suk-Ja;Lee, Jae-Seo
    • Imaging Science in Dentistry
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    • 제42권4호
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    • pp.237-242
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    • 2012
  • Purpose: The objectives of this study were to survey the radiographic exposure parameters, to measure the patient doses for intraoral dental radiography nationwide, and thus to establish the diagnostic reference levels (DRLs) in intraoral dental X-ray examination in Korea. Materials and Methods: One hundred two intraoral dental radiographic machines from all regions of South Korea were selected for this study. Radiographic exposure parameters, size of hospital, type of image receptor system, installation duration of machine, and type of dental X-ray machine were documented. Patient entrance doses (PED) and dose-area products (DAP) were measured three times at the end of the exit cone of the X-ray unit with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for adult mandibular molar intraoral dental radiography, and corrections were made for room temperature and pressure. Measured PED and DAP were averaged and compared according to the size of hospital, type of image receptor system, installation duration, and type of dental X-ray machine. Results: The mean exposure parameters were 62.6 kVp, 7.9 mA, and 0.5 second for adult mandibular molar intraoral dental radiography. The mean patient dose was 2.11 mGy (PED) and 59.4 $mGycm^2$ (DAP) and the third quartile one 3.07 mGy (PED) and 87.4 $mGycm^2$ (DAP). Doses at university dental hospitals were lower than those at dental clinics (p<0.05). Doses of digital radiography (DR) type were lower than those of film-based type (p<0.05). Conclusion: We recommend 3.1 mGy (PED), 87.4 $mGycm^2$ (DAP) as the DRLs in adult mandibular molar intraoral dental radiography in Korea.

상용 보호열판법 열전도율 측정장비를 사용한 열유속법의 열전도율 값 보정에 대한 실험적 연구 (Experimental Study on Correction of Thermal Conductivity Obtained by Heat Flow Method using Commercial Guarded Hot Plate Method Apparatus)

  • 이진성;김경수;김유일;우석민;윤승진
    • 한국해양공학회지
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    • 제29권2호
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    • pp.169-174
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    • 2015
  • This paper addresses experimental methodologies to measure the temperature-dependent thermal conductivity of the insulation materials popularly used for LNG cargo containment systems. The measurement techniques considered in this paper are the guarded hot plate (GHP) method and heat flow method (HFM). The former is based on the power supplied to the hot plate to keep the temperature constant, and the latter is based on a direct heat flux measurement. In order to improve the accuracy of the HFM, the thermal conductivity obtained by GHP was cross-compared with the HFM results, and a calibration factor was derived. It was found that the thermal conductivities measured by the two methods corresponded well under room temperature, but the deviation tended to slightly increase as the temperature decreased. Because of the easy installation and operability of HFM, it can be used to measure thermal conductivity in a large scale mock-up test or unit insulation panel test, where the GHP method is difficult to apply.

간호학생의 죽음에 대한 태도 (Attitude toward Death in Nursing Students)

  • 정선영;이은경;김보혜;박진화;한민경;김인경
    • 한국간호교육학회지
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    • 제17권2호
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    • pp.168-177
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    • 2011
  • Purpose: The purpose of this study was to investigate the attitude toward death in Korean nursing students. Method: The sample consisted of 365 baccalaureate nursing students. The questionnaires included questions on sociodemographics and death-related characteristics of the participants, and the Fear of Death and Dying Scale (FODS) to measure the attitude toward death. Result: The mean of the FODS score was 2.63 out of 4, so the participants had a slightly negative attitude toward death. There were statistically significant differences between gender, religion, religion activity, perceived health status, experience of parents' death, experience of friend's death, and overall FODS score. Among the four subscales of overall FODS, the score of the fear of death of self was significantly higher in the participants who experienced clinical practice and who experienced patient's death in the intensive care unit compared to the emergency room. Conclusion: Based on the study results, educational programs to change the attitude toward death are required before clinical practice. Programs need to consider nursing students' gender and religion, and give opportunity to share experiences and feelings about death of family or friend. In addition, using standardized patients and simulators is advised in the need for simulation training.

표준전지 및 표준전지 항온함 제작에 관한 연구 (A Study on the Standard Cell and Its Enclosure)

  • 황의진;이화심;이진욱;강홍열
    • 대한화학회지
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    • 제36권6호
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    • pp.857-863
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    • 1992
  • 기전력의 단위인 volt를 유지하기 위하여 사용되는 Weston 산성 포화전지를 만들어, 온도가 일정하도록 특별히 고안하여 제작한 enclosure에 넣어 성능을 평가하였다. 전지 제조에 사용되는 황산카드뮴은 진공 상태에서 재결정하였으며, 수은이 분산된 황산수은(I) 침전은 전기분해에 의해 제조하였으며, 카드뮴 아말감도 전기분해에 의하여 정확한 조성으로 제조할 수 있었다. 표준전지 항온함은 순환식 항온조를 이용하여 제작하였으며, 실내 온도가 심하게 변하는 경우에도 ${\pm}$5 mK 이내로 표준전지의 온도를 안정시킬 수 있었다. 표준전지의 기전력을 5${\sim} 30^{\circ}C$의 온도 범위에서 측정하였으며 전지간의 기전력 표준편차는 약 1ppm이었다.

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농촌주민의 지역사회조직 참여 실태 분석 (Socio-demographic Heterogeneity of Community Participation in Rural, Korea)

  • 박덕병;조영숙
    • 한국지역사회생활과학회지
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    • 제16권2호
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    • pp.61-73
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    • 2005
  • This study aims to examine the socio-demographic heterogeneity of community participation in rural Korea. Data was collected through interviews with 1,870 rural householders and housewives who have lived in Up or Myen as an administrative unit of rural communities, and analyzed by the SPSS/PC Win V.10 program. The statistical techniques used for this study were frequency and percentile. The major findings of this study were as follows. Firstly, the extent to which rural people have participated in community organizations were: cooperative groups, $80.8\%$; religious groups, $20.6\%$; learning groups, $12.7\%$; political groups, $9.8\%;$ civil groups $6.7\%$; and voluntary groups, $5.3\%$. Whereas the numbers were high for community participation in groups related to agricultural production, participation in civil and voluntary groups were lower. Secondly, it showed that people who lived in urbanized and high population density areas were more likely to participate in community groups. The diversity of community organizations was different according to the level of rurality. Thirdly, farm householders were more likely to participate in religious, civil and voluntary groups than non-farm householders. Fourthly, people with higher education, females, those in the 40 to 50 age groups were more likely to participate in community organizations. Fifthly, even though men are more likely to participate in political parties, women were more likely then men to agree that women should participate in political parties. This empirical study could support the results of Sundeen (1988) and Wilson and Musick (1997) in that education was related positively to community participation. In addition, we concluded that community participation in a rural development process has two main considerations: philosophical and pragmatic. This implies that there is room for government to enable and facilitate 'true' community participation. That can be done through policy reform which creates a permissive environment for community decision-making and input, in addition to simply supporting community development through financial assistance.

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Opportunities for Joint Cooperation in R&D for FEALAC Countries: On Nanotechnology and Biotechnology

  • Trujillo, Ivan Montenegro;Jimenez, Edgar E Gonzalez;Ospina, Monica Botero
    • STI Policy Review
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    • 제7권2호
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    • pp.106-131
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    • 2016
  • The general purpose of this paper is to identify opportunities for and to measure existing collaboration on research and development between institutions from the countries of Asia and Latin America in FEALAC's framework, in the fields of biotechnology and nanotechnology and their convergence. The methodological approach includes scientific and technological surveillance and research seeking to identify both the R&D and innovation capacities of the countries as well as the degree of international cooperation between countries of the two regions; case studies and a study of the governance framework of international collaboration in R&D about issues considered global challenges. The study has three main findings. First, nanotechnology, biotechnology and their convergence contribute to solving the problem of contamination by heavy metals affecting most of the countries that are part of FEALAC and to address problems arising from the accelerated rate of energy consumption, which also contributes to environmental damage. In this scenario, important business opportunities arise from the adaptation and development of bio-refinery technologies. Second, the scientific relationship between FEALAC countries, mainly between Asian and Latin American countries, is weak as can be seen in research for articles and patents. But there is plenty of room and potential for improvement. Third, current and upcoming joint R&D programs and projects should be linked both to existing governance structures and to new ones that serve as experiments of STI public policy regarding innovative management of intellectual property and capacity building. Practical implications are included in lessons learned and a set of recommendations involving a couple of proposals. One proposal calls for research and innovation in promising fields for international cooperation. Another proposal creates mechanisms in the governance framework for sharing knowledge, capacity building, and funding.

일지역 신경외과 중환자실내의 통행량에 따른 낙하균 분석 (A Study of Airborne Microbes in the NSICU According to Number of Persons Who Pass through Every Hour)

  • 박형숙;강인순;김진화;어현주
    • 기본간호학회지
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    • 제11권1호
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    • pp.41-48
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    • 2004
  • Purpose: The purpose of this study was to analyze the colony count of airborne microbes contamination every hour in the Neurosurgical Intensive Care Unit (NSICU) in order to identify the relationship of colony count to person-visits. Method: Data were collected during from 11:00 a.m. September 5 to 11:00 a.m. September 6, 2002. This study used blood agar & nutrient agar and handtally counter (USA) for collection of airborne microbes and number of person-visits. Data was analyzed using the SPSSWIN 10.0 with means, Pearson correlation coefficient, and simple regression. Result: The result of this study are as follows. Total colony count of airborne microbes for 24 hours in the NSICU was 4,609. Total number of person-visits to the NSICU was 15,347. The highest scores fur the total colony count in different areas of the NSICU was the rear door, followed by the preparation room, and the front entrance, while the lowest count was in the isolation rooms. There was a statistically significant relationship between colony count and number of person-visits to the NSICU. The most frequently airborne microbes in the NSICU were Micrococcus, CNS, Staphylococcus Micrococcus, Aureus. Conclusion: These findings indicate that the number of person-visits in hospitals influences total colony count of airborne microbes. This study contributes to assessment of biological indoor air quality in hospital and in the development of an NSICU care plan.

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연일층군 이암에서 산출되는 알루미늄 황산염 광물의 결정화학 및 생성 (I): 배사알루미나팅, 하이드로베사알루미나이트 및 메타배사알루미나이트 (Crystal Chemistry and Paragenesis of Aluminum Sulphates from Mudstones of the Yeonil Group (I): basaluminite, hydrbasaluminite, and metabasaluminite)

  • 노진환
    • 한국광물학회지
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    • 제11권1호
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    • pp.1-12
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    • 1998
  • In Pohang area, basaluminite accompanying a little amounts of hydrobasalumnite, super-genetically occurs as whitish cryptocrystalline (2-4 $\mu\textrm{m}$) clay-like aggregates in the vicinity of altered carbonate concretions embedded within mudstones of the Tertiary Yeonil Group. A hydrobasaluminite changed readily into a basaluminite at room temperature in air, and, in turn, into a metabasaluminite when heating to 150$^{\circ}$~30$0^{\circ}C$. For the basaluminite, a monoclinic unit-cellparameters (a=14.845$\AA$, b=10.006$\AA$, c=11.082$\AA$, $\beta$=122.15$^{\circ}$) were calculated by X-ray powder diffraction data. Its basal reflections (001 and 002) are XRD analyses strongly indicate that the aluminum sulphate mineral has a layer structure and, at least, three types of water, i.e., (1) interlayer water (9.0 wt %), (2) crystal water (8.0 wt %), and (3) structural water (19.0 wt %). may present in its lattice. Based on TG-DTG data combined with EDS and IR analyses, a new chemical formula of Al5SO4(OH)134H2O was given to the basaluminite. Field occurrence and stable isotope data ($\delta$18O, $\delta$D, $\delta$34S) for the basaluminite seem to reflect that it was formed by the leached meteoric solution from surrounding mudstones during or after uplifting. An interaction of the acid solution with carbonate concretion and the resultant local neutralization of the fluid rich in Al3+ and SO42- are major controls on the basaluminite formation.

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