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本文根据作者们在[9]中所引入的参数 R_α(X)讨论了平坦巴纳赫空间的有关性质。主要结果是:定理1 如果 X 是平坦巴纳赫空间,则 R_(?)(X)=2。定理2 如果 X 是平坦巴纳赫空间,X~*是它的对偶空间,则 R_(?)1(X~*)=(?)。定理3 如果因子空间有一个是平坦巴纳赫空间,则其 l_p-乘积空间一定是平坦巴纳赫空间(1
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Investigation of ultra—thin ferromagnetic films with a simple cubic lattice 总被引:1,自引:0,他引:1 下载免费PDF全文
Using Green‘s function method,we investigate ferromagnetic films with a simple cubic lattice containing up to ten monolayers.The Hamiltonian includes the Heisenberg exchange term,surface anisotropy (SA) and dipole interaction (DI).We calculate the magnetization as a function of temperature and film thickness,and we analyse the behaviour of spin canting.The result is in agreement with experiments.We calculate phase diagrams of SA versus DI to show the conditions under which spontaneous magnetization can occur.As a special case,we discuss the Heisenberg model without SA and DI. 相似文献
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CO adsorption on small Aun(n=1-7) clusters supported on a reduced rutile TiO2(110) surface:a first-principles study 下载免费PDF全文
CO adsorption on small Au n(n = 1-7) clusters which are supported by a partially reduced rutile TiO 2(110) surface has been investigated by the first-principles method.The low coordinated sites of Au clusters are favorable for CO adsorption.CO-Au n-TiO 2 system displays surface magnetism.There is a strong interaction between the adsorbed CO molecule and the supported Au clusters. 相似文献
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网络环境下基于价值理论的我国消费者购买意愿影响因素研究 总被引:1,自引:0,他引:1
随着网上零售业快速发展,如何提高网络消费者购买意愿已成为人们关注的焦点。论文运用感知价值理论分析了网络消费者购买意愿影响因素,提出了影响网络消费者购买意愿的重要研究假设,构建了网络消费者购买意愿假设模型,采用结构方程模型方法对样本数据进行了定量研究。研究结果揭示了网络消费者的风险态度通过感知利益和感知风险对感知价值的间接影响,而感知价值与购买意愿显著正相关。最后,论文对研究结果进行了讨论,提出了促进我国网上零售业发展的建议. 相似文献
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运用时间分辨激光诱导荧光技术和激光诱导等离子体方法测量了铂原子的15条奇宇称高激发态能级的自然辐射寿命.测量结果处于6.1到116 ns之间,且误差低于10%.经比较,与前人结果在误差范围内符合很好.据文献调研所知,结果中有5条高度接近60000 cm~(-1)的高激发态能级的寿命值是未见报道的. 相似文献
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在pH 9.10的氨性缓冲溶液中硫离子能导致荧光试剂水杨醛缩氨基硫脲荧光强度猝灭,荧光猝灭的程度随硫离子含量的增加而增大.其硫离子的质量浓度在20~440μg·L-1范围内与荧光强度的猝灭程度呈线性关系,方法的检出限(S/N=3)为6.7μg·L-1.据此建立了测定痕量硫化物的荧光猝灭分析方法.该方法操作简便、反应迅速、灵敏度高,可直接用于工业废水、自来水、井水中硫化物的测定. 相似文献
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The ternary Ni-AI-Co embedded-atom-method potential for γ/γ' Ni-based single-crystal superalloys: Construction and application* 下载免费PDF全文
An Ni-AI-Co system embedded-atom-method potential is constructed for the γ(Ni)/γ'(Ni3A1) superalloy based on experiments and first-principles calculations. The stacking fault energies (SFEs) of the Ni(Co, A1) random solid solutions are calculated as a function of the concentrations of Co and A1. The calculated SFEs decrease with increasing concentrations of Co and A1, which is consistent with the experimental results. The embedding energy term in the present potential has an important influence on the SFEs of the random solid solutions. The cross-slip processes of a screw dislocation in homogenous Ni(Co) solid solutions are simulated using the present potential and the nudged elastic band method. The cross-slip activation energies increase with increasing Co concentration, which implies that the creep resistance of γ(Ni) may be improved by the addition of Co. 相似文献
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基于满足目前高效复杂的调制技术对功率放大器线性化度越来越高的需求的目的,采用模拟预失真技术设计了一种线性化器,用来改善Ka频段氮化镓(GaN)固态功放的非线性化失真。通过改进传统的并联式二极管预失真电路,采用开环技术,将两个肖特基二极管并联。改变二极管的偏置状态,得到不同的改善程度的预失真信号。结合使用专用电磁仿真软件ADS2013做电路仿真,通过参数扫描得到二极管偏置状态的初始值,为实物调试提供理论基础。通过对已加工的实物测试,结果表明:增益幅度补偿达到6.4dB,相位补偿达到28°。 相似文献