• 제목/요약/키워드: F and $F^{+}$-Center

검색결과 4,102건 처리시간 0.038초

Characterization of carrier-envelope-offset frequency of a femtosecond laser stabilized by the direct CEP locking method

  • Luu, Tran Trung;Lee, Jae-Hwan;Kim, Eok-Bong;Park, Chang--Yong;Yu, Tae-Jun;Nam, Chang-Hee
    • 한국광학회:학술대회논문집
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    • 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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    • pp.241-242
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    • 2009
  • Characterics of carrier-envelope-offset frequency ($f_{ceo}$) of a femtosecond laser stabilized by the direct locking method were investigated using two f-to-2f interferometers. The stability of $f_{ceo}$ was comaparable to that achieved with a conventional PLL method.

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Ammonium Hexafluorotitanate 전구체로부터 습식 공정을 이용한 불소 함유 TiO2 나노 분말 제조 및 광촉매 특성 연구 (Study on preparation and photocatalytic properties of F-containing TiO2 nanopowders using wet-process from Ammonium Hexafluorotitanate)

  • 이덕희;박재량;이찬기;김현모;박경수
    • 한국분말재료학회지
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    • 제25권3호
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    • pp.226-231
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    • 2018
  • F-containing $TiO_2$ nanopowders are synthesized using simple wet processes (precipitation-based and hydrothermal) from ammonium hexafluorotitanate (AHFT, $(NH_4)_2TiF_6$) as a precursor to apply as a photocatalyst for the degradation of rhodamine B (RhB). The surface properties of the prepared samples are evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results confirm that the synthesized anatase $TiO_2$ has sphere-like shapes, with numerous small nanoparticles containing fluorine on the surface. The photocatalytic activity of F-containing $TiO_2$ compared with F-free $TiO_2$ is characterized by measuring the degradation of RhB using a xenon lamp. The photocatalytic degradation of F-containing $TiO_2$ exhibits improved photocatalytic activity, based on the positive effects of adsorbed F ions on the surface.

정수장에서 막여과 전처리용 F/A 공정 개발을 위한 Filtralite 여재의 적용성 연구 (A Study of Filtralite Media Applicability for Development F/A Process of Membrane Filtration Pre-treatment Process in the Water Purification Plant)

  • 김준현;전용성;곽영주;장정우
    • 멤브레인
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    • 제25권6호
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    • pp.503-514
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    • 2015
  • 본 연구는 잔류함으로써 문제를 일으킬 수 있는 응집제를 사용하지 않고 물리적인 처리만을 사용하는 막여과 정수처리의 전처리로 F/A 공정을 구성하고자 하였고 이를 구성하는 여재의 성능을 연구하였다. 특히, 탁질 물질과 유기물 제거가 가능한 것으로 알려진 Filtralite의 도입 가능성을 검토하였다. Filtralite의 탁도 제거효율은 원수대비 83~84%로 여과사와 비슷한 결과 값을 나타내었으며 여재표면에 잘 발달된 공극 때문에 유기물 제거능은 여과사보다 50% 더 높게 나타났다. 따라서 F/A 공정을 구성함에 있어 여과사보다 Filtralite가 더 효율적이라 검토되었다. 활성탄과 연계한 F/A 공정을 구성하여 막여과 처리 시스템의 전처리효율을 실험한 결과, TOC 농도는 TMP의 증가에 큰 영향을 주는 것으로 판단되어 막오염 저감에 유기물 제어가 중요함을 확인하였으며 유기물 제거 효율이 뛰어난 여재 사용이 필요할 것으로 판단되었다.

전문치료형 캠프 참가자의 캠프 전 후의 심리변화 (서울금연지원센터 금연캠프 참가자 대상으로) (Psychological changes in residential treatment for heavy smokers in Seoul Tobacco Control Center)

  • 천은주
    • 한국융합학회논문지
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    • 제11권2호
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    • pp.315-321
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    • 2020
  • 본 연구의 목적은 서울 전문치료형 금연캠프를 이용한 중,고도 흡연자들의 전, 후 동기변화를 보고 6개월 성공 및 실패집단 간 동기 차이를 확인하기 위함이다. 연구 설계는 금연동기척도의 금연캠프 전, 후 변화와 6개월 금연성공 및 실패집단의 차이를 비교했고, 연구기간은 2015년 8월 1일부터 2018년 12월 31일까지 수집된 자료를 활용하였다. 연구대상자는 총 1317명이며, 남자는 1248명(94.8%), 여자는 69명(5.2%)이며, 흡연기간은 31~40년이 413명(31.3%)으로 가장 많았다. 캠프 후 동기가 향상되었으며, 6개월 성공집단이 실패집단보다 전반적인 금연동기(F=6.52, p=.011), 하위영역인 전숙고단계(F=5.12, p=.024)와 숙고단계(F=.90, p=.341), 준비1단계(F=5.79, p=.016), 준비2단계(F=1.33, p=.249)에서 유의한 차이가 있는 것으로 나타났다. 따라서 중,고도 흡연자를 대상으로 금연 캠프 프로그램이 금연동기를 향상시키며 6개월 금연성공집단이 더 금연동기가 높은 것을 확인할 수 있었다.

Deletion Timing of Cic Alleles during Hematopoiesis Determines the Degree of Peripheral CD4+ T Cell Activation and Proliferation

  • Guk-Yeol Park;Gil-Woo Lee;Soeun Kim;Hyebeen Hong;Jong Seok Park;Jae-Ho Cho;Yoontae Lee
    • IMMUNE NETWORK
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    • 제20권5호
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    • pp.43.1-43.11
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    • 2020
  • Capicua (CIC) is a transcriptional repressor that regulates several developmental processes. CIC deficiency results in lymphoproliferative autoimmunity accompanied by expansion of CD44hiCD62Llo effector/memory and follicular Th cell populations. Deletion of Cic alleles in hematopoietic stem cells (Vav1-Cre-mediated knockout of Cic) causes more severe autoimmunity than that caused by the knockout of Cic in CD4+CD8+ double positive thymocytes (Cd4-Cre-mediated knockout of Cic). In this study, we compared splenic CD4+ T cell activation and proliferation between whole immune cell-specific Cic-null (Cicf/f;Vav1-Cre) and T cell-specific Cic-null (Cicf/f;Cd4-Cre) mice. Hyperactivation and hyperproliferation of CD4+ T cells were more apparent in Cicf/f;Vav1-Cre mice than in Cicf/f;Cd4-Cre mice. Cicf/f;Vav1-Cre CD4+ T cells more rapidly proliferated and secreted larger amounts of IL-2 upon TCR stimulation than did Cicf/f;Cd4-Cre CD4+ T cells, while the TCR stimulation-induced activation of the TCR signaling cascade and calcium flux were comparable between them. Mixed wild-type and Cicf/f;Vav1-Cre bone marrow chimeras also exhibited more apparent hyperactivation and hyperproliferation of Cic-deficient CD4+ T cells than did mixed wild-type and Cicf/f;Cd4-Cre bone marrow chimeras. Taken together, our data demonstrate that CIC deficiency at the beginning of T cell development endows peripheral CD4+ T cells with enhanced T cell activation and proliferative capability.

Penicillium griseofulvum F1959, High-Production Strain of Pyripyropene A, Specific Inhibitor of Acyl-CoA: Cholesterol Acyltransferase 2

  • Choi, Jung-Ho;Rho, Mun-Chual;Lee, Seung-Woong;Choi, Ji-Na;Lee, Hee-Jeong;Bae, Kyung-Sook;Kim, Koan-Hoi;Kim, Young-Kook
    • Journal of Microbiology and Biotechnology
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    • 제18권10호
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    • pp.1663-1665
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    • 2008
  • Acyl-coenzyme A: cholesterol acyltransferase (ACAT) catalyzes cholesterol esterification and plays an important role in the intestinal absorption of cholesterol, hepatic production of lipoproteins, and accumulation of cholesteryl ester within cells. During the course of screening to find ACAT inhibitors from microbial sources, the present authors isolated pyripyropene A from Penicillium griseofulvum F1959. Pyripyropene A, an ACAT2-specific inhibitor, has already been produced from Aspergillus fumigatus. Yet, Aspergillus fumigatus is a pathogen and only produces a limited amount of pyripyropene A, making the isolation of pyripyropene A troublesome. In contrast, Penicillium griseofulvum F1959 was found to produce approximately 28 times more pyripyropene A than Aspergillus fumigatus, plus this report also describes the ideal conditions for the production of pyripyropene A by Penicillium griseofulvum F1959 and its subsequent purification.

콩 시들음병에 관여하는 Fusarium균의 다양성 및 병원학적 특성 (Diversity and Pathogenic Characteristics of Fusarium Species isolated from Wilted Soybeans in Korea)

  • 최효원;김승노;홍성기
    • 한국균학회지
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    • 제48권3호
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    • pp.297-312
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    • 2020
  • 2014년부터 2016년까지 국내 콩 재배 포장에서 시들음 증상을 보이는 시료에서 진균을 분리한 결과, Fusarium spp., Colletotrichum spp., Rhizoctonia spp., Macrophomina sp., Phytophthora spp., Calonectria ilicicola가 분리되었고, Fusarium균이 79.1%로 가장 많이 분리되었다. 53개의 Fusarium균을 균학적 특성에 의해 동정한 결과, F. solani, F. oxysporum, F. graminearum, F. fujikuroi 등 4개의 종 복합체(species complex)로 동정되었다. 염기서열분석을 통한 종 동정을 위해 translation elongation factor 1 alpha (TEF) 유전자 부위를 계통분석한 결과, F. solani, F. oxysporum, F. commune, F. asiaticum, F. fujikuroi 등 5종으로 확인되었다. 44개 Fusarium균주의 병원성을 확인하기 위하여 콩 3개 품종을 대상으로 유묘 침지 접종한 결과, F. asiaticum은 병원성이 없거나 미미한 것으로 나타났다. 병원성이 있는 10개 균주를 선발하여 기주범위를 조사한 결과, F. solani, F. oxysporum, F. commune은 콩에만 병원성이 있었고, F. fujikuroi는 콩, 강낭콩, 황동부콩, 흑동부콩 및 팥에 병원성을 보였다. 또한 13개 콩 품종을 대상으로 저항성 검정을 수행한 결과, F. commune과 F. fujikuroi는 모든 품종에 병을 일으켰다. 장기콩, 풍산나물콩, 소청자콩은 Fusarium에 의한 시들음병에 비교적 저항성이 것으로 나타났고, 황금올콩, 참올콩은 감수성 품종으로 확인되었다.

겔화에 의한 Water-in-Oil에멀젼의 안정성;이산화티타늄($TiO_{2}$)이 함유된 Sun-block Cream의 응용 (Stability of Water-in-Oil Emulsion by Gelation;Application of Sun-Block Cream containing Titanium Dioxide($TiO_{2}$))

  • 김인영
    • 한국응용과학기술학회지
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    • 제17권2호
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    • pp.67-75
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    • 2000
  • Cosmetic industries have recently developed sun-block products, which are composed of W/O or O/W emulsion system. It was very difficult for waterproofing product to show the stability in W/O emulsion with $TiO_{2}$. To enhance the stability of W/O emulsion, it needs to be combined with the water and oil soluble components as the gelling agents. The emulsifiers used in W/O were 3.0% of cetyl dimethicone copolyol, 2.0% of sorbitan sesquioleate as the basic emulsifiers, and 0.6% of quaternium-18 bentonite and 1.5% of dextrin palmitate as stabilizer were used. The content of titanium dioxide was optimized up to 8.0%. Titanium dioxide was used as the UV scattering powder coated with $Al_{2}O_{3}$(UV-sperse T40/TN). The sunscreen cream prepared with W/O emulsion system by using QB and DP showed higher stability than that of W/O emulsion system by using each QB and DP. W/O emulsion from Formula 3 for passing one year was very durable more than F1 and F2. Within W/O emulsion by observing F1, F2 and F3 for one year, F3 was more excellent than F2 and F3 when they were observed at RT, $4^{\circ}C$, $40^{\circ}C$, because F3 used the mixed QB and DP in W/O emulsion. The zeta potential for F1, F2, and F3 after one year were 21, 30 and 43, respectively. From these result F3 was found best stable emulsion. The in-vitro SPF value for F3 was 35 for the initial product at room temperature and also, the in-vitro SPF values of F3 was 32 for after one year. Finally, the mean in-vivo SPF value of 10 volunteers for F3 was 27.3 by the Korea cosmetic association made the rules of SPF.