RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      선택해제
      • 좁혀본 항목 보기순서

        • 원문유무
        • 원문제공처
        • 등재정보
        • 학술지명
        • 주제분류
        • 발행연도
        • 저자
          펼치기

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • Effect of Network Polymerization on the Pressure-Induced Structural Changes in Sodium Aluminosilicate Glasses and Melts: <sup>27</sup>Al and <sup>17</sup>O Solid-State NMR Study

        Lee, Sung Keun,Yi, Yoo Soo,Cody, George D.,Mibe, Kenji,Fei, Yingwei,Mysen, Bjorn O. American Chemical Society 2012 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.116 No.3

        <P>Probing the pressure-induced structural changes and the extent of disorder in aluminosilicate glasses and melts at high pressure remains a challenge in modern physical and chemical sciences. With an aim of establishing a systematic relationship between pressure, composition, and glass structures, we report <SUP>27</SUP>Al and <SUP>17</SUP>O 3QMAS NMR spectra for sodium aluminosilicate glasses [Na<SUB>2</SUB>O:Al<SUB>2</SUB>O<SUB>3</SUB>:SiO<SUB>2</SUB> = 1.5:0.5:2<I>n</I> with <I>n</I> = 1 (NAS150520, <I>X</I><SUB>SiO2</SUB> = 0.5), 2 (NAS150540, <I>X</I><SUB>SiO2</SUB> = 0.67), and 3 (NAS150560, <I>X</I><SUB>SiO2</SUB> = 0.75)], quenched from melts at pressures up to 8 GPa. We also explore the stability of the <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al cluster in the highly depolymerized, NAS150520, glass at high pressure. For given glass composition, the <SUP>[5,6]</SUP>Al peak intensity increases with increasing pressure. The population of <SUP>[5,6]</SUP>Al increases linearly with <I>X</I><SUB>SiO2</SUB> from NAS150520 (<I>X</I><SUB>SiO2</SUB> = 0.5) to NAS150560 glass (<I>X</I><SUB>SiO2</SUB> = 0.75) at both 6 and 8 GPa. The <SUP>[5,6]</SUP>Al/<I>X</I><SUB>SiO2</SUB> ratio also tends to increase with pressure, indicating a possible relationship between <SUP>[5,6]</SUP>Al fraction and <I>X</I><SUB>SiO2</SUB> that depends on pressure. The effect of pressure on the network connectivity in the sodium aluminosilicate glasses is manifested in the increase in <SUP>[4]</SUP>Si–O–<SUP>[5,6]</SUP>Al peak intensity and the decrease in the nonbridging oxygen (NBO) fraction with increasing pressure. The fraction of <SUP>[4]</SUP>Si–O–<SUP>[5,6]</SUP>Al in NAS150520 is smaller than in NAS150560. Taking into consideration the pressure-induced Al coordination transformation in the fully polymerized glass (albite, Na<SUB>2</SUB>O:Al<SUB>2</SUB>O<SUB>3</SUB>:SiO<SUB>2</SUB>= 1:1:6, NBO/T = 0), the fraction of <SUP>[5,6]</SUP>Al at a given pressure varies <I>nonlinearly</I> with variations of NBO/T. <SUP>[5,6]</SUP>Al fraction at 8 GPa increases with decreasing degree of melt polymerization from ∼8% for fully polymerized albite melt (NBO/T = 0) to ∼37% for partially depolymerized melt (NAS150560, at NBO/T = 0.29). Then it gradually decreases to ∼15% for NAS150520 with further increase in NBO/T of 0.67. This observed trend in the densification behavior at a given pressure indicates competing densification mechanisms involving steric hindrance vs changes of NBO fraction in the silicate melts. The NMR results also suggest that both NBO and BO, particularly <SUP>[4]</SUP>Si–O–<SUP>[4]</SUP>Si, interact with Na<SUP>+</SUP>, and thus the Na<SUP>+</SUP> distribution is likely to be homogeneous around both NBO and BO at high pressure without spatial segregation of silica-rich and alkali-rich domains for the glass compositions studied here. The presence of the <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al cluster is distinct in the NMR spectrum for NAS150520 glass at both 6 and 8 GPa. A new scheme of pressure-induced structural transitions in silicate melts involving <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al includes the formation of <SUP>[4]</SUP>Al–O–<SUP>[5]</SUP>Al.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-3/jp206765s/production/images/medium/jp-2011-06765s_0008.gif'></P>

      • SCISCIESCOPUS

        Development of a microchannel plate based beam profile monitor for a re-accelerated muon beam

        Kim, Bongho,Bae, Sunghan,Choi, Hyunsuk,Choi, Seonho,Kawamura, Naritoshi,Kitamura, Ryo,Ko, Ho San,Kondo, Yasuhiro,Mibe, Tsutomu,Otani, Masashi,Razuvaev, Georgiy P.,Won, Eunil Elsevier 2018 Nuclear Instruments & Methods in Physics Research. Vol.899 No.-

        <P><B>Abstract</B></P> <P>A beam profile monitor (BPM) based on a microchannel plate has been developed for muon beams with low transverse momentum for the measurement of the muon anomalous magnetic moment and electric dipole moment at high precision, with capability of diagnosing muon beams of kinetic energy range from a few keV to 4 MeV. The performance of the BPM has been evaluated using a surface muon beam at J-PARC and additionally with an ultraviolet (UV) light source. It has been confirmed that the BPM has a dynamic range from a few to 1 <SUP> 0 4 </SUP> muons per bunch without saturation. The spatial resolution of the BPM has been estimated to be less than 0.30 mm. The positron background from muon decays is an obstacle in muon beam profile monitoring and a partial discrimination of the positrons has been achieved under discrete particle conditions.</P>

      • Near-threshold photoproduction of φ mesons from deuterium

        CLAS Collaboration,Qian, X.,Chen, W.,Gao, H.,Hicks, K.,Kramer, K.,Laget, J.M.,Mibe, T.,Qiang, Y.,Stepanyan, S.,Tedeschi, D.J.,Xu, W.,Adhikari, K.P.,Amaryan, M.,Anghinolfi, M.,Ball, J.,Battaglieri, M. North-Holland Pub. Co 2011 Physics letters: B Vol.696 No.4

        We report the first, kinematically-complete measurement of the differential cross section of φ-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K<SUP>+</SUP> and K<SUP>-</SUP> near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections dσdt for the initial photon energy range of 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on φ-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region.

      • The extraction of φ–N total cross section from d(γ,p<sup>K+</sup><sup>K−</sup>)n

        Qian, X.,Chen, W.,Gao, H.,Hicks, K.,Kramer, K.,Laget, J.M.,Mibe, T.,Stepanyan, S.,Tedeschi, D.J.,Xu, W.,Adhikari, K.P.,Amaryan, M.,Anghinolfi, M.,Baghdasaryan, H.,Ball, J.,Battaglieri, M.,Batourine, V Elsevier 2009 Physics letters: B Vol.680 No.5

        <P><B>Abstract</B></P><P>We report on the first measurement of the differential cross section of <I>φ</I>-meson photoproduction for the d(γ,p<SUP>K+</SUP><SUP>K−</SUP>)n exclusive reaction channel. The experiment was performed using a tagged-photon beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the d(γ,p<SUP>K+</SUP><SUP>K−</SUP>)n channel and those from a previous publication on coherent <I>φ</I> production on the deuteron has been carried out to extract the φ−N total cross section, <SUB>σφN</SUB>. The extracted φ−N total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for <I>φ</I> photoproduction on the proton.</P>

      연관 검색어 추천

      이 검색어로 많이 본 자료

      활용도 높은 자료

      해외이동버튼