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For single crystalline and melt-textured samples there exist several different activation energies for fluxoid creep, which are related to various vortex orientations and hopping directions. We discuss how to obtain these anisotropic activation energies from magnetic relaxation data and present measured results of a melt-textured YBCO sample. 相似文献
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本文研究行满秩Hankel矩阵分解为一个真正的(proper)Hankel矩阵与一个退化的(de- generate)Hankel矩阵之拟直和的存在性及唯一性问题. 相似文献
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Hermite矩阵广义Schur补的特征值交错性质 总被引:1,自引:0,他引:1
何淦瞳 《纯粹数学与应用数学》2008,24(3)
研究了Hermite矩阵的Schur补的特征值交错性质,将Smith建立的结果推广到Hermite矩阵的广义Sclmr补. 相似文献
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By presenting a counterexample,the author of paper (ZHAO Li-feng.J.Math.Res.Exposition,2007,27(4): 949–954) declared that some assertions in papers of L Yun-xia,ZHANG Shu-qing (J.Math.Res.Exposition,1999,19(3): 598–600),HE Gan-tong (J.Math.Res.Exposition,2002,22(1): 79–82) and YUAN Hui-ping (J.Math.Res.Exposition,2001,21(3): 464–468) are wrong.In this note,we point out that the counterexample is wrong.Further discussion on these assertions and some related results are also given. 相似文献
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基于醌类以及含"2-苯基萘型"结构单元的衍生物在临床上表现出良好的抗肿瘤活性,设计了取代吲哚苯醌衍生物。以2-取代吲哚衍生物为底物,乙腈为反应溶剂,在相转移催化剂苄基三乙基氯化铵和无水碳酸钾存在下,与四溴苯醌反应,合成了9个未见文献报道的2-取代吲哚-1,4-醌衍生物(2a^2c,3a^3c,4a^4c),其结构经1H NMR,13C NMR和HR-MS(ESI)表征。体外抗肿瘤活性实验表明,该类化合物对人肺癌细胞系(A549)、人乳腺癌细胞系(MDA-MB-231)及宫颈癌细胞系(Hela)具有抑制作用,其中化合物2b和3c对人乳腺癌细胞系MDA-MB-231具有良好的抑制活性。 相似文献
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合成了6种1-取代-4,5-二(4-氯苯基)咪唑.以对氯苯乙酸和氯苯为原料,经Friedel-Crafts酰基化反应、二氧化锡氧化、与多聚甲醛和乙酸铵环合制备了中间体4,5-二(4-氯苯基)咪唑(5),5再经取代得到3个1-取代-4,5-二-(4-氯苯基)咪唑类化合物6a-c.6a再分别与液体胺经亲核取代反应得到3个1-取代乙酰胺类-4,5-二-(4-氯苯基)咪唑类化合物7a-c.目标化合物结构用核磁共振氢谱和红外光谱进行了表征. 相似文献
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Increasing rewriting speed of optical rewritable e-paper by selecting proper liquid crystals 下载免费PDF全文
Effect of interaction between liquid crystal (LC) and photoalignment material on speed of optical rewriting process is investigated. The theoretical analysis shows that smaller frank elastic constant K22 of liquid crystal corresponds to larger twist angle, which gives rise to larger rewriting speed. Six different LC cells with the same boundary conditions (one substrate is covered with rubbed polyimide (PI) and other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity (450 nm, 80 mW/cm2). The results demonstrate that with suitable liquid crystal, LC optical rewriting speed for e-paper application can be obviously improved. For two well known LC materials E7 (K22 is larger) and 5CB (K22 is smaller), they require 11 s and 6 s corresponding to change alignment direction for generating image information. 相似文献
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INVESTIGATION OF THE EFFECT OF SLOW NEUTRON IRRADIATION ON HALOGEN-DOPED HIGH-Tc SUPERCONDUCTORS AND ITS MECHANISM 下载免费PDF全文
Irradiation effect of low-fluence (-108 n/cm2 ) slow neutrons on halogen-doped superconductors is presented in this paper. And the mechanism of the effect is also described from the viewpoint of nuclear physics for both fast and slow neutrons on high-temperature superconductors (HTSC). It is shown ex-perimentally and theoretically that slow neutrons of low fluence has a similar irradiation effect to that of fast neutron beams with an energy En>0.1 MeV and fluence 1016-1018 n/cm2-However,quite differ-ent mechanisms are involved in them: Fast neutrons transfer their energies through elastic scattering in HTSC, whereas slow neutrons give off their energies during the slow neutron capture (n,γ) reaction. 相似文献