京津冀协同发展背景下河北省信息产业关联效应分析

信息产业作为京津冀协同发展的战略重点,其价值创造过程,与各产业部门之间存在直接或间接的产业关联,以此直接或间接地带动经济发展.采用投入产出分析法,以河北省2012年投入产出表为依据,定量分析河北省信息制造业和信息服务业对各产业部门的经济关联效应.研究结果表明:河北省信息制造业主要以需求上游相关产业投入的形式,拉动各产业部门发展;而河北省信息服务业则主要以供给下游相关产业生产的方式,推动各产业部门发展;并且河北省信息制造业对各产业部门的总体关联程度,强于信息服务业,即河北省信息制造业更能够广泛地影响经济发展.     

Flexible tuning microwave permeability spectrum in [ferromagnet/antiferromagnet]_n exchange-biased multilayer stack structure

NiFe/[IrMn/NiFe/IrMn] 5 /[NiFe/IrMn] 4 /NiFe structured exchange-biased multilayer films are designed and prepared by magnetron sputtering. The static and the microwave magnetic properties are systematically investigated. The results reveal that adding a partially pinned ferromagnetic layer can effectively broaden the ferromagnetic resonance linewidth toward the low frequency domain. Moreover, a wideband multi-peak permeability spectrum with a 3.1-GHz linewidth is obtained by overlapping the spectra of different partially pinned ferromagnetic layers and [antiferromagnet/ferromagnet/antiferromagnet] n stacks. Our results show that the linewidth of the sample can be feasibly tuned through controlling the proper exchange bias fields of different stacks. The designed multilayered thin films have potential application for a tunable wideband high frequency noise filter.     

基于Logistic模型的创新生态系统的种群关系研究

京津冀产业创新生态系统是京津冀协同发展的重要内容.从产业创新生态系统外部和内部两个角度对京津冀电子信息制造业创新生态系统进行剖析,一方面运用生态学理论构建京津冀电子信息制造业创新生态系统,借用Logistic模型分析京津冀区域电子信息制造业创新生态系统种群间的动态演化,协同效应初步显现;另一方面结合仿真方法模拟研究京津冀电子信息制造业创新生态系统内部各类种群之间的演化关系和演化规律.互惠共生是电子信息制造业创新生态系统演化的最佳关系模式.各创新主体之间不同的演化关系导致动态创新生态系统不同的演化方向,最终达到平衡状态,并提出相应对策建议.     

Soft Magnetic Thin Films FeCoHfO for High-Frequency Noise Suppression Applications

A series of FeCoHfO films were fabricated by dc magnetron reactive sputtering at varying partial pressure of oxygen （Po2） from 0 to 11.7%, and the electrical and magnetic properties of films have been studied. It is shown that optimal Fe43.29 Co19.51Hf7.49 O29.71 films with desired properties can be obtained when the films were prepared under Po2= 5.1%. The films show superior properties of low coereivity, Hc ∽5.5 Oe, relatively high saturation magnetization, 47rMs · 18.3 kG, high anisotropy field Hk ∽ 65 Oe, and high electrical resistivity ρ∽ 2675 μΩ·cm. Permeability spectra shows that the natural ferromagnetic resonant frequency is as high as 3.1 GHz. The combined merits of the film make the films taken as an ideal candidate material for high-frequency applications such as noise suppressor. In addition, the effects of the film thickness and annealing treatment on the magnetic properties are also reported.     

Theoretical Investigations on the Off-Center Displacement of Co2+ in SrO by Analyzing Its Anisotropic g Factors

The off-center displacement of Co^2＋ ion in SrO crystal is investigated by analyzing its anisotropic g factors gx, gy and gz through diagonalization of the 6 × 6 energy matrix within ^4T1 ground state for a 3d^7 ion under rhombic symmetry. In the matrix, the contributions from the admixtures of various J（= 1/2, 3/2, 5/2） states and the fourth-order term Dn of rhombic crystal-fields and the ligand orbitals and spin-orbit coupling interactions, which are usually ignored in the previous studies, are considered. Both g factors （gx = 4.172, gy = 5.004 and gz = 2.133） and the off-displacement value （△ R ≈ 0.023 am） show good agreement with the experimental data.     

Effects of Layer Deposition Sequence on Microstructure and Magnetostatic Coupling of Spin-Valves with Amorphous CoNbZr Layer

We investigate spin-valve sandwiches with thin amorphous CoNbZr as soft layers. The magnetoresistance (MR), microstructure, and magnetostatic coupling are studied in these sandwiches with different layer deposition sequences. For the CoNbZr/Cu/Co sandwich, the CoNbZr underlayer provides a smoother surface on which smooth Cu and Co layers can subsequently grow. The Cu spacer is dense and pinholes-free, leading to a good ““spin valve““ effect with a larger MR ratio of 3.8%. For the Co/Cu/CoNbZr sandwich, however, the Cu spacer is rough and pinholes were observed, which could induce a direct ferromagnetic coupling. Correlated rougher surfaces on both the sides of the Cu spacer were also observed, giving rise to an ““orangepeel““ coupling of about O. 105 erg/cm^-2. This strong ferromagnetic coupling in Co/Cu/CoNbZr results in a lower MR ratio of 1.6%. Moreover, upon proper thermal annealing, the CoNbZr/Cu/Co has a larger MR enhancement and a superior thermal stability to 350℃ due to the dense and homogenous structure in the spacer layer.     

氮化铁薄膜晶相合成热分析及其磁性

研究Fe-N体系晶相转变(相变)规律对于高效合成高自旋极化率的g'-Fe4N薄膜材料非常重要.利用同步热分析(TG-DSC)研究了氮化铁薄膜的相变规律. TG-DSC的结果显示,在10℃/min的升温速率下,g'-FeN薄膜在常温到800℃之间共有5次相变,分别为I,g'-FeN→x-Fe2N;II,x-Fe2N→e-Fe3N;III,e-Fe3N→g'-Fe4N; IV, g'-Fe4N→g-Fe;以及V, g-Fe→a-Fe.利用真空退火技术有效调控了氮化铁薄膜的晶相.X-射线衍射测试结果显示,直接在纯氮气中溅射得到的氮化铁薄膜是单相的g'-FeN,经350, 380和430℃退火可分别获得单相的x-Fe2N, e-Fe3N和g'-Fe4N.研究了氮化铁薄膜的磁学性能.振动样品磁强计测试结果显示, g'-Fe4N薄膜在面内/面外表现出明显的磁各向异性,属于典型的磁形状各向异性.