H.F.Yu 1)
,
P.Q.Liu 1) and W.H.Wang 2) 1) Department of Materials Science and Engineering
,
Shenyang Architectural and Civil Engineering Institute
,
Shenyang 110015
,
China 2) Department of Airport
,
CAAC Eastnorth Management
,
Shenyang 110043
,
China
金属学报(英文版)
The properties of a new magnesium Oxychloride cement (MOC) material formed by silica fume uniformly mix in MOC paste was presents. The influence of silica fume on the water resistance and compressive strength of MOC paste was invesigated in this study. It is shown that when 30 weight percent of silica fume is added to the MOC paste, a high strength and water resisting new material with 112MPa compressive strength and 1 00 water resisting coefficient could by obtained.
关键词:
silica fume
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null
,
null
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null
肖剑荣
,
徐慧
,
李幼真
,
刘雄飞
,
马松山
,
简献忠
中国有色金属学报
使用CF4和CH4为源气体,利用射频等离子体增强化学气相沉积法,制备了a-C:F:H薄膜样品.采用拉曼光谱仪、傅里叶变换红外光谱仪、X射线光电子能谱仪(XPS)对薄膜的结构进行了测试和分析.研究发现:该膜呈空间网状结构,膜内碳与氟、氢的结合主要以sp3形式存在,而sp2形式的含量相对较少;在薄膜内主要含有C-Fx(x=1,2,3)、C-C、C-H2、C-H3等以及不饱和C=C化学键;同时,薄膜中C-C-F键的含量比C-C-F2键的含量要高.在不同功率下沉积的薄膜,其化学键结构明显不同.
关键词:
a-C:F:H薄膜
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等离子体增强化学气相沉积
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低介电常数
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化学键
罗湘宁
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王晶
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陈赓华
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杨乾声
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张利华
低温物理学报
doi:10.3969/j.issn.1000-3258.2000.01.003
本文采用偏置电流反转的频率与磁通调制频率相等的方案,研制了带偏置电流反转的dc SQUID测试系统,明显降低了YBCO双晶结dc SQUID的1/f噪声.在3Hz处,磁通噪声由静态偏置时的降低到.1/f噪声的角频率从1kHz下降到3Hz.前放的设计,采用低噪声集成电路,整个磁通锁定环置于测试杆顶端,简化了电路,提高了测试系统的稳定性.在白噪声区,测得最低磁通噪声为 .前放的噪声系数为1.1dB.
关键词:
Zhiyong Liu
材料科学技术（英文）
Here we report the fabrication and superconductivity of the iron-based arsenic oxide SmO1-xFxFeAs compound. X-ray diffraction (XRD) results prove that the lattice parameters a and c decrease systematically with increasing x in between 0<x≤0.35, but when x>0.35 the a and c increase with the decrease of x in
the SmO1-xFxFeAs. The critical temperature (Tc) increases with increasing x in between 0.15≤x≤0.3, while x>0.3 the Tc decreases with the increase of x. It is found that at x=0.3 SmO0.7F0.3FeAs has the highest onset resistivity transition temperature of 55.5 K. The critical current density (Jc) value at 10 K for the obtained SmO0.7F0.3FeAs is 1.3×105 A/cm2 (0 T). Meanwhile one can estimates Hc2(0) from the slope of the Hc2(T) curve at T=Tc (HC2 is the upper critical field), and for the 90% normal-state resistivity (ρn) criterion (Tc=55 K), Hc2(0) is determined to be ~253 T.
关键词:
SmO1-xFxFeAs compound
林碧洲
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许承晃
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吴季怀
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邱继晨
人工晶体学报
doi:10.3969/j.issn.1000-985X.1998.01.022
描述了掺氧族离子(O2-,S2-,Se2-)NaCl晶体中(F+2)H心的制备过程,报道了氧族离子稳定的(F+2)H心的吸收光谱和发射光谱,测量了这些(F+2)H心的室温避光稳定性.研究表明,氧族离子对F+2心的稳定作用顺序为O2-＜Se2-＜S2-,而受这三种离子扰动的(F+2)H心的光谱峰位相对于纯F+2心的移动大小亦为这一顺序.这一顺序与它们相应元素的电子亲合能顺序相同(分别为1.47,2.02,2.07eV).从而,纠正了根据离子大小为预测的结果O2-＜S2-＜Se2-.本文结果对(F+2)H色心激光晶体材料的研究具有指导意义.研究还表明,随着离子半经的增大,生长出优质的掺杂晶体越来越困难.
关键词:
色心激光
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激活心
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掺杂效应
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稳定性
Physica B-Condensed Matter
The spin-Hamiltonian parameters (g factors g(parallel to), g(perpendicular to) and hyperfine structure constants (161)A(parallel to), (161)A(perpendicular to), (163)A(parallel to), (163)A(perpendicular to)) for Dy(3+) at the tetragonal H(f)(4+) site of H(f)SiO(4) crystal are calculated from the diagonalization (of energy matrix) method. In the method, we add the Zeeman (or magnetic) and hyperfine interaction terms to the conventional Hamiltonian used in the calculations of crystal-field energy levels. The 66 X 66 energy matrix concerning the new Hamiltonian is established by considering the ground multiplet (6)H(15/2) and the first to fifth excited multiplets (6)H(J) (where J=13/2, 11/2,9/2, 7/2 and 5/2), and the crystal-field parameters in the energy matrix are calculated from the superposition model. From the calculations, the spin-Hamiltonian parameters of H(f)SiO(4):Dy(3+) are explained reasonably and the signs of hyperfine structure constants for (161)Dy(3+) and (161)Dy(3+) isotopes in H(f)SiO(4) are suggested. The results are discussed. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
Electron paramagnetic resonance;Crystal-field theory;Point defect;Dy(3+);H(f)SiO(4);superposition-model analysis;single-crystals;paramagnetic-resonance;structure silicates;zircon;growth;hafnon;field;epr;er3
刘志勇
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索红莉
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马麟
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赵俊静
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倪宝荣
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郭志超
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闫镔杰
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刘敏
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吴紫平
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周美玲
稀有金属材料与工程
研究了F掺杂对铁基超导体SmO0.7F0.3FeAs的制备和性能的影响.利用二次固相反应在1120℃保温40h制备出超导临界转变温度(Tc)为56.5 K的SmO0.7F0.3FeAs超导体样品,其临界电流密度Jc为2.4× 105 A/cm2(10 K,0 T).研究发现,SmO1-xFxFeAs样品的Tc受F含量的强烈影响,晶格参数的变化也是诱导SmO1-xFxFeAs超导体的Tc变化的原因之一.在此基础上详细研究了F元素过掺杂对铁基超导体SmO1-xFδFeAs(δ＞x)制备参数和性能的影响.F元素过量时,在不降低SmO1-xFδFeAs超导性能的情况下,F元素过掺杂可以一定程度地降低样品制备时的热处理温度和极大地缩短热处理时间.1100℃时保温20h制备的SmO0.7F0.35FeAs和SmO0.7F04FeAs样品的Tc分别为56和55K;其临界电流密度Jc分别为1.9×105和1.7× 105 A/cm2 (10K,0 T).
关键词:
铁基超导体
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SmO1-xFδFeAs
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掺杂
崔焱
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林艳
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谢刚
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杨大锦
黄金
doi:10.11792/hj20140412
采用循环伏安法和线性扫描技术等电化学研究方法，系统研究了电解液体系中各阴阳离子对锑电沉积过程的影响。通过测定Sb3＋、NH4＋、F-、SO2-4及草酸等组分不同质量浓度下体系的循环伏安曲线、稳态极化曲线及塔菲尔曲线，分析了各离子在电解过程中的电化学行为及作用，确定了H2 SO4-NH4 F-SbF3电解液体系合适的成分为Sb3＋90～120 g／L、NH4＋50 g／L、F-80 g／L、H2 SO4360 g／L、H2 C2 O44～10 g／L。在此电解液体系下进行了粗锑的电解精炼试验，阴极锑纯度为99．9436％，达到国标1号精锑标准，阴极电流效率为97．60％。
关键词:
锑
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电解精炼
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H2 SO4 -NH4 F-SbF3体系
甘肇强
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陆新华
材料科学与工程学报
doi:10.3969/j.issn.1673-2812.2002.02.004
改变CHF3/CH4流量比R=[CHF3]/([CHF3]+[CH4]),采用微波电子回旋共振等离子体化学气相沉积(MWECR-CVD)方法沉积a-C:F:H薄膜.a-C:F:H薄膜的结构和光学带隙使用傅立叶变换红外光谱和紫外-可见光谱来表征.红外结果表明,在低流量比R(R<64%)下,薄膜的红外特征结构主要以-CF(1060cm-1),-CF2(1120cm-1)以及-CHx(2800～3000cm-1)的伸缩振动为主;在高流量比R(R＞64%)下,薄膜表现为类聚四氟乙烯(PTFE)的结构特征,典型的红外特征峰是位于1220cm-1处的-CF2反对称伸缩振动.薄膜的光学带隙Eg随流量比R的变化表现为先降后升.进一步研究表明,薄膜中的H和F浓度调制着薄膜的 C==C共轭双键结构,使光学带隙Eg从2.37到3.3之间变化.
关键词:
a-C:F:H薄膜
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傅立叶变换红外光谱
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紫外可见光谱
Superconductor Science & Technology
It is shown that the superconductivity in Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) compounds can be modulated by internal (chemical) pressure. The internal pressure is induced by Gd substitution for Ce in CeFeAsO(0.84)F(0.16), which compresses the crystal lattice. The temperature dependences of resistivity and magnetization show that the superconducting-transition temperature T(c) is enhanced from 40 K for CeFeAsO(0.84)F(0.16) to 47.5 K for Ce(0.6)Gd(0.4)FeAsO(0.84)F(0.16). The increase and subsequent decrease of Tc upon application of external pressure, as observed previously in LaFeAsO(0.89)F(0.11), is entirely confirmed by the modulation of Tc of the Ce(1-x)Gd(x)FeAsO(0.84)F(0.16) superconductors by internal pressure.
关键词:
layered quaternary compound;43 k;iron
