• 제목/요약/키워드: Iron-based

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Brief Review on Iron-based Superconductors: are There Clues for Unconventional Superconductivity?

  • Oh, Hyung-Ju;Moon, Ji-Soo;Shin, Dong-Han;Moon, Chang-Youn;Choi, Hyoung-Joon
    • Progress in Superconductivity
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    • 제13권2호
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    • pp.65-84
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    • 2011
  • Study of superconductivity in layered iron-based materials was initiated in 2006 by Hosono's group, and boosted in 2008 by the superconducting transition temperature, $T_c$, of 26 K in $LaFeAsO_{1-X}F_X$. Since then, enormous researches have been done on the materials, with $T_c$ reaching as high as 55 K. Here, we review briefly experimental and theoretical results on atomic and electronic structures and magnetic and superconducting properties of FeAs-based superconductors and related compounds. We seek for clues for unconventional superconductivity in the materials.

A review on angle resolved photoemission spectroscopy studies of Fe-based superconductors

  • Seo, J.J.;Kim, C.
    • 한국초전도ㆍ저온공학회논문지
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    • 제16권2호
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    • pp.7-19
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    • 2014
  • Since the discovery of iron-based superconductors in 2008, extensive and intensive studies have been performed to find the microscopic theory for the high temperature superconductivity in the materials. Electronic structure is the basic and essential information that is needed for the microscopic theory. Experimentally, angle resolved photoelectron spectroscopy (ARPES) is the most direct tool to obtain the electronic structure information, and therefore has played a vital role in the research. In this review, we review what has been done so far and what is needed to be done in ARPES studies of iron-based superconductors in search of the microscopic theory. This review covers issues on the band structure, orbital order/fluctuation, and gap structure/symmetries as well as some of the theories.

Helicobacter pylori 감염과 철 결핍의 관계: 937명의 사춘기 환아의 혈청 유병률 연구 (The Relationship between Helicobacter pylori Infection and Iron-Deficiency: Seroprevalence Study in 937 Pubescent Children)

  • 김상종;김봉림;김순기;최연호
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • 제5권2호
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    • pp.129-135
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    • 2002
  • 목 적: 철분 결핍에 노출되기 쉬운 사춘기 소아에서 H. pylori 감염과 철 결핍성 빈혈의 상관 관계를 알아보고자 하였다. 방 법: 혈색소, 혈청 철, 총 철 결합능, 혈청 페리틴, H. pylori에 대한 변역글로붙린 G 항체를 937명(남자 475명, 여자 462명)을 대상으로 측정하였다. 이들의 연령은 10세에서 18세였다. H. pylori 감염의 유병률은 빈혈, 저 페리틴혈증, 철 결핍, 철 결핍성빈혈 유무에 따라 두 군으로 비교하였다. 또한 H. pylori 감염 유무에 따라 혈색소, 혈청 철, 총 철 결합능, 트랜스페린 포화도, 혈청 페리틴의 농도를 비교하였다. 결 과: 빈혈, 철 결핍, 철 결핍성 빈혈, H. pylori 감염에 대한 각각의 유병률은 8.1%, 9.1%, 3.1%, 20.8%였다. 빈혈, 저 페리틴혈증, 철 결핍 각각의 군에서 H. pylori 감염율은 34.2%, 29.5%, 35.3% 이었고, 빈혈이 없는 군에서는 H. pylori 감염률이 19.6%, 저 페리틴혈증이 없는 군은 19.2%, 철 결핍성 빈혈이 없는 군은 19.4%이었다. H. pylori 감염율은 철 결핍성 빈혈군에서 44.8%, 정상군에서 20.0%이었다. 혈색소와 철분 농도는 유의한 차이가 없었지만 혈철 페리틴 농도는 H. pylori 감염군에서 유의하게 감소하였다. 결 론: H. pylori 감염은 사춘기 청소년에서 철결핍과 관련있을 것으로 생각된다.

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경남 일부지역 여대생의 철 영양상태에 관한 연구 (Iron Status in Female College Students in the Gyeongnam Area)

  • 박미영;김성희
    • Journal of Nutrition and Health
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    • 제44권3호
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    • pp.222-230
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    • 2011
  • This study was undertaken to investigate iron status and related factors in female college students residing in Gyeongnam. The subjects were divided into normal (40.8%) and iron deficiency (ID) groups (59.2%) by iron status. Mean height, weight, lean body mass, percent body fat, body mass index, and wrist to hip ratio were not significantly different between the groups, but basic metabolic rate was significantly higher in the normal group than that in the ID group. The levels of hemoglobin, hematocrit, serum ferritin, transferrin saturation, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were significantly higher in the normal group than those in the ID group. However, total iron binding capacity was significantly lower in the normal group than that in the ID group. Daily intake of protein, heme-Fe, niacin, and vitamin C were significantly higher in the normal group than those in the ID group. The mean intake of protein, Fe, niacin, vitamin $B_{12}$, and vitamin C based on the Korean recommended intake (RI) were significantly higher in the normal group than those in the ID group. The mean intakes of Ca, vitamin $B_{12}$, and folate in both groups were < 75% of the Korean RI. In conclusion, increasing dietary heme-Fe and vitamin C may be helpful for preventing ID anemia in female college students.

제철 소결공정에 대한 단입자 연소 모델의 응용 (Application of Intra-particle Combustion Model for Iron Ore Sintering Bed)

  • 양원;최상민;진홍종
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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    • pp.181-188
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    • 2006
  • Operation parameters for large scale industrial facility such as iron making plant are carefully selected through elaborate tests and monitoring rather than through a mathematical modeling. One of the recent progresses for better energy utilization in iron ore sintering process is the distribution pattern of fuel inside a macro particle which is formed with fines of iron ore, coke and limestone. Results of model tests which have been used as a basis for the improved operation in the field are introduced and a theoretical modeling study is presented to supplement the experiment-based approach with fundamental arguments of physical modeling, which enables predictive computation beyond the limited region of tests and adjustment. A single fuel particle model along with one-dimensional bed combustion model of solid particles are utilized, and thermal processes of combustion and heat transfer are found to be dominant consideration in the discussions of productivity and energy utilization in the sintering process.

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설계 민감도법을 이용한 유도 전기장 분포 제어를 위한 철심구조 최적화 연구 (Optimization of Iron Core Structure for Controlling Induced Electric Field Distribution Using the Continuum Design Sensitivity Analysis (CDSA))

  • 박준구
    • 대한전기학회논문지:시스템및제어부문D
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    • 제55권8호
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    • pp.397-400
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    • 2006
  • An optimized iron core structure of stimulating coil are presented in order to control the induced electric field distribution using the Continuum Design Sensitivity Analysis (CDSA) combined with a commercially available generalized finite element code (OPERA). The results show that a Figure-Of-Eight (FOE) coil as well as a circular coil with the proposed iron core structure can increase induced electric field intensity by more than two times and make better field localization, compared with those of existing stimulation coil with a air core. After considering manufacturing constraints, a practical iron core structure based on the proposed optimized one is proposed and its performance is analyzed.

Preparation and Characterization of Ophthalmic Hydrophilic Silicone Lens Containing Zinc Oxide and Iron Oxide Nanoparticles

  • Shin, Su-Mi;Sung, A-Young
    • 한국재료학회지
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    • 제31권8호
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    • pp.427-432
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    • 2021
  • This study uses silicone monomer, DMA, crosslinking agent EGDMA, and initiator AIBN as a basic combination to prepare hydrogel lenses using fluorine-based perfluoro polyether and iron oxide and zinc oxide nanoparticles as additives. After manufacturing the lens using iron oxide nanoparticles and zinc oxide nanoparticles, the optical, physical properties, and polymerization stability are evaluated to investigate the possibility of application as a functional hydrogel lens material. As a result of this experiment, it is found that the addition of the wetting material containing fluorine changes the surface energy of the produced hydrogel lens, thereby improving the wettability. Also, the addition of iron oxide and zinc oxide nanoparticles satisfies the basic hydrogel ophthalmic lens properties and slightly increases the UV blocking performance; it also increases the tensile strength by improving the durability of the hydrogel lens. The polymerization stability of the nanoparticles evaluated through the eluate test is found to be excellent. Therefore, it is judged that these materials can be used in various conditions as high functional hydrogel lens material.

산화철의 품질 안정화 (A Study on th Quality Stabilization of Iron Oxide)

  • 변태봉;한기현;김형석;배우현
    • 자원리싸이클링
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    • 제7권4호
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    • pp.55-63
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    • 1998
  • 냉연공장의 산회수 설비로부터 제조되는 소프트 페라이트용 산화철의 품질편차를 감소시키기 위한 연구로서, 품질편차 원인분석, 산회수 조업조건 및 산화철 성분분석, 그리고 산화철의 품질변화를 조사하고 이로부터 도출된 산화철 품질편차 최소화를 위한 적정 조업 pattern을 확립하였다. 산화철의 품질편차를 감소시키기 위해서는 산화철의 원료가 되는 폐산의 발생, 즉 산세처리 대상재인 강종의 구분과 발생 폐산의 분리저장 및 분리운전이 필요하였다. 폐산의 분리, 운전조업 및 생성 산화철의 분리, 저장으로 $SiO_2$함량 약 80ppm, 편차 $\pm$ 10 ppm 이하의 산화철을 제조할 수 있었다. 추가필터 설치의 운영에 따라 산화철의 품질편차 감소뿐만 아니라 고순도 산화철의 생산도 가능할 것으로 예상되었다.

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사상 자동화를 위한 로봇의 Blind Force Control 기술 개발 (A Development of Blind Force Control of Robot for Grind Automation)

  • 이우원;박찬호;임계영
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2006년도 전력전자학술대회 논문집
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    • pp.158-162
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    • 2006
  • A lot of pieces of iron plate are used to build a ship. The states of cutting surface of iron are however bended or ununiformly cuttled by cutting machine. These may cause bad Quality of painting, and shorter lifetime of iron by rust. In this paper, a new approach of grinding force control method which teaching of robot is not required is proposed to avoid long preparation time of robot and to improve the productivity. The way used in this paper is just like a blind man works through the road with stick only.

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