排序方式: 共有27条查询结果,搜索用时 656 毫秒
11.
以CeCl3·7H2O作为铈源、碳酸氢铵作为沉淀剂、乙二胺作为络合剂,采用水热法制备了三角星状二氧化铈微结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)、拉曼光谱(Raman)、荧光分光光度计(PL)、紫外可见近红外分光光度计(UV-Vis)和综合物性测量系统(PPMS)等对此CeO2样品的晶相、形貌、表面化学组分、缺陷、光学和磁学性质做了相关研究,分析并提出了三角星状二氧化铈微结构生长机理.结果表明,制备的CeO2具有室温铁磁性,其室温铁磁性与样品中Ce3和氧空位有关.样品对波长小于400 nm的紫外光有很强的吸收,但对波长大于400 nm的可见光有很好的透过性,这表明样品能很好的用做紫外吸收剂. 相似文献
12.
13.
We propose a scheme for the effective polarization and manipulation of electron spin by using a quantum dot with both charge and spin bias. Using the equation of motion for Keldysh nonequilibrium Green function, we study the spin accumulation and polarization for the system. Through analytical analysis and a few numerical examples, it is demonstrated that fairly large spin accumulation and polarization can be produced due to the breakingsymmetry of the chemical potential for different electron spin in the leads. Moreover, the direction and the strength of the spin polarization can be conveniently controlled and tuned by varying the charge bias or the gate voltage. 相似文献
14.
The derivation of Eq. (28) in the original paper [Chin. Phys. B 30 117101 (2021)] is corrected. 相似文献
15.
17.
A new sulfate inorganic framework, {(C2H8N)9[Nd5(SO4)12]·2H2O}n(1) templated by organic amine, has been solvothermally synthesized and characterized by TGA, PXRD and single-crystal X-ray diffraction. Compound 1 crystalizes in monoclinic, space group C2/c with a = 20.570(5), b = 35.815(8), c = 10.106(2) , C318H72N9Nd5O50S12, Mr = 2315.73, V = 6765(3) , Z = 4, Dc = 2.274 g·cm-3, μ = 4.253 mm-1, F(000) = 4520, 2.52θ25°, λ(MoKα) = 0.71073 , T = 273(2) K, the final R = 0.0401, wR = 0.1022 and S = 1.042. X-ray diffraction analysis reveals that complex 1 possesses a 3D inorganic sulfate framework with large 20-membered ring(20 MR) and 10-membered ring(10 MR) channels constructed by two kinds of SBUs. Moreover, the UV-vis and luminescent properties of complex 1 were also investigated. 相似文献
19.
基于有限差分方法,研究周期梯度磁场调制下二维电子气的电子性质.结果表明:由于周期梯度磁场的存在,体系展现出丰富的电子能带结构.其子带的宽度随|ky|增大而不断变窄,|ky|越大势阱越深;由于在ky > 0和ky < 0两个区域的有效势能不一样,其能带结构在两个区域不一致且在ky > 0的区域中形成更多束缚态.通过改变磁条周期、磁条到2DEG的距离及磁化强度研究其对电子能带结构的影响. 相似文献
20.
色散和非线性效应对高斯脉冲综合影响的理论分析 总被引:4,自引:3,他引:1
从光孤子传输所满足的非线性薛定谔方程出发,采用单独分析和综合分析对比,分析了影响高斯脉冲传输的色散、非线性等因素,结果表明:二阶色散参量只会影响脉冲的幅值,对脉冲形状影响不大,而输入脉冲的啁啾则是使脉冲发生形变的主要原因;在啁啾、三阶色散和五阶非线性的共同作用下,它们对脉冲都会产生较大的影响,且存在相互影响和制约作用,在某一临界值,对脉冲存在着较高的压缩增益效应和"整形"作用.从理论上提出了改善高斯光脉冲在光纤中传输特性的解决方案,这对光纤孤子通信的实践过程具有一定的理论借鉴意义. 相似文献