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981.
Jie Guo Seng Ghee Tan Mansoor Bin Abdul Jalil Dax Enshan KohGuchang Han Hao Meng 《Journal of magnetism and magnetic materials》2011,323(1):83-87
The effect of itinerant spin moment (m) dynamic in spin transfer switching has been ignored in most previous theoretical studies of the magnetization (M) dynamics. Thus in this paper, we proposed a more refined micromagnetic model of spin transfer switching that takes into account in a self-consistent manner of the coupled m and M dynamics. The numerical results obtained from this model further shed insight on the switching profiles of m and M, both of which show particular sensitivity to parameters such as the anisotropy field, the spin torque field, and the initial deviation between m and M. 相似文献
982.
A facile method to synthesize magnetic polymer nanospheres with multifunctional groups 总被引:1,自引:0,他引:1
Xiaojuan Zhang Wei JiangYuanfeng Ye Zhiqiang FengZhendong Sun Fengsheng LiLingyun Hao Jianjun Chu 《Journal of magnetism and magnetic materials》2011,323(11):1440-1444
Magnetic poly(styrene methyl methacrylate)/Fe3O4 nanospheres with ester groups were prepared by a modified one-step mini-emulsion polymerization in the presence of Fe3O4 ferrofluids. The effects of monomer dose, surfactant content, ferrofluid concentration and initiator content on the particle characteristics such as the size, morphology and magnetic properties were investigated by Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis and vibrating sample magnetometer. The results indicated that magnetic nanospheres were superparamagnetic with high saturation magnetization of 51.0 emu/g and corresponding magnetite content of 61.5 wt%. Subsequently, magnetic nanospheres with carboxyl and amino groups were also obtained by hydrolysis and ammonolysis reaction. These magnetic nanospheres with multifunctional groups have biomedical applications. 相似文献
983.
The pseudoscalar quarkonia exclusive decays to light mesons still poses a challenge to the theoretical understanding of quarkonium properties in decay. In this work, we evaluate the processes of pseudoscalar heavy quarkonium decays into vector meson pairs, especially the helicity suppressed processes of ηb→J/ψJ/ψ and ηc→VV. In the framework of NRQCD, the branching fraction of Br[ηb→J/ψJ/ψ] are evaluated at the next-to-leading order of perturbative QCD; and within the light-cone distribution formalism, we calculate also the higher twist effects in these processes. Numerical results show that the higher twist terms contribute more than what from the NLO QCD corrections in the process of ηb→J/ψJ/ψ. It is found that the experimental results on ηc→VV are hard to be understood by merely the quark model and perturbative QCD calculation. 相似文献
984.
985.
Hao Sun 《Mathematische Zeitschrift》2014,277(3-4):739-747
In this paper we prove that for any smooth projective variety of Albanese fiber dimension two and of general type, the \(6\) -canonical map is birational. And we also show that the \(5\) -canonical map is birational for any such variety with some geometric restrictions. 相似文献
986.
令p为大于3的素数.在一定维数限制下,通过把齐性空间SU(2n)/Sp(n)分解为若干个同伦可结合,同伦可交换的H-空间的乘积,进而得到了SU(2n)/Sp(n)的p素H-同伦指数的一个上界. 相似文献
987.
988.
989.
研究了基于NZ30K合金开发的新型Mg-3Nd-0.2Zn-0.4Zr-0.2Mn镁合金耐腐蚀性、体外降解行为特性及浸提液细胞生物毒性. 采用金相显微镜得到新型镁合金金相显微图, 采用扫描电镜(Scanning Electron Microscope, SEM)获取SEM图; 采用武汉科思特电化学工作站进行电化学测试, 并绘制动电位极化曲线, 以磷酸盐缓冲液(Phosphate Buffer Solution, PBS)模拟体液环境, 记录氢气析出体积并计算腐蚀速率; 利用细胞完全培养基测定pH值、重量变化曲线; 获取大鼠骨髓间充质干细胞(Bone Mesenchymal Stem Cells, BMSCs), 并利用完全细胞培养基制作新型镁合金浸提液, 检测细胞生物活性, 以ZA75镁合金为基础添加0.3%Mn元素制成合金作为对照组, 比较腐蚀电位、体外降解情况以及细胞活性. 结果表明: 新型Mg-3Nd-0.2Zn-0.4Zr-0.2Mn镁合金横截面等轴晶体组织细小均匀性较好, 纵截面呈长条状组织均匀性稍差; 自腐蚀电位较高, 为-1.3912V; 自腐蚀电流密度较低, 为7.37×10-7 A?cm-2; 体外析氢量低, 失重量、pH值变化幅度相对较小; 降解速率下降后呈现小范围上升后趋于平缓; 具有良好的细胞相容性, 可以促进BMSCs细胞增殖分化. 相似文献
990.
S.R. Xu Y. Hao J.C. Zhang Y.R. Cao X.W. Zhou L.A. Yang X.X. Ou K. Chen W. Mao 《Journal of Crystal Growth》2010,312(23):3521-3524
We have investigated the unintentional impurities, oxygen and carbon, in GaN films grown on c-plane, r-plane as well as m-plane sapphire by metal-organic chemical vapor deposition. The GaN layer was analyzed by secondary ion mass spectroscopy. The different trend of the incorporation of oxygen and carbon has been explained in the polar (0 0 0 1), nonpolar (1 1 2¯ 0) and semipolar (1 1 2¯ 2) GaN by a combination of the atom bonding structure and the origin direction of the impurities. Furthermore, it has been found that there is a stronger yellow luminescence (YL) in GaN with higher concentration of carbon, suggesting that C-involved defects are originally responsible for the YL. 相似文献