温度和电子有效质量对隧穿磁致电阻偏压依赖关系的影响

本文研究温度和势垒中的电子有效质量对铁磁隧道结中隧穿磁致电阻(TMR)的偏压依赖和变号行为的影响。所求得的TMR随温度上升明显减小的结果与实验一致。除了前文中指出的势垒高度(Ф)以外, 还发现垒中电子的有效质量(mB)是物理上控制TMR变号的另一个重要因素。相应于TMR变号的临界电压(VC)将随Ф升高而增大, 但随mB增大而减小。此外, 零偏压的TMR和临界电压VC将因温度升高而减小。作者希望上述理论结果将有助于实验研究。     

Energy Transfer and Green Emitting Properties of Solid Solution PbGd_(1-x)Tb_xB_7O_(13)(x = 0～1)

A series of Tb-doped solid solutions PbGd_(1-x)Tb_xB_7O_(13)(x = 0~1) were synthesized by high-temperature solid state reaction method. The luminescence properties were investigated under UV(274 nm) and near-UV(372 nm) excitation. The emission spectrum by 274 nm exciting reveals a charge-transfer between Gd~(3+) and Tb~(3+) ions. Under near-UV light(372 nm) excitation, PbGd_(1-x)Tb_xB_7O_(13):x Tb~(~(3+)) exhibits intense green emission centered at 543 nm due to the ~5D_4→~7F_5 transition of Tb~(3+) activator. The optimum doping concentrations were found to be x = 0.8 with the quantum efficiency of 35%. One may expect that PbGd_(1-x)Tb_xB_7O_(13) has the potential to be used as a green phosphor activated by near near-UV light.     

利用金属掩模法制备钉扎型磁性隧道结

利用金属掩模法和Ir22Mn78合金反铁磁钉扎层，制备了四种钉扎型的Py/Al2O3/Py，Py/Al2O3/Co，Co/Al2O3/Py和Co/Al2O3/Co磁性隧道结，坡莫合金的成分为Py＝Ni79Fe21.例如：利用狭缝宽度为100?μm的金属掩模，直接制备出室温隧穿磁电阻比值为17.2%的磁性隧道结Co/Al2O3/Co，其结电阻为76Ω,结电阻和结面积的积矢为76×10_{4Ωμm2，自由层的偏转场为1114?A/m，并且在外加磁场0.1114A·m-1之间时室温磁电阻比值 关键词： 磁性隧道结 隧穿磁电阻 磁随机存储器 金属掩模}     

c向切割LiNbO3∶Fe晶体中光折变光散射

提出了一个新的理论机理:c向切割LiNbO₃∶Fe晶体中光折变背向光散射是由光生伏特电流的不均匀性引起的,并经过理论计算,比较成功的解释了实验观察到的各种现象 关键词： 光折变 散射 光生伏特     

稳定干扰AGR2乳腺癌细胞系的建立及其功能

将AGR2基因的shRNA表达序列连接到pSUPER质粒中,获得pSUPER-shAGR2质粒,经测序鉴定后,将pSUPER-shAGR2和pSUPER质粒通过Lipofectamine2000转染MCF7细胞,经流式细胞仪和600μg.mL-1G418筛选获得稳定干扰AGR2的MCF7细胞系和对照细胞系,Western blot检测其RNA干扰效果,MTT检测细胞     

Length dependence of linear and nonlinear optical properties of finite-length BN（5,0） nanotube

In this paper, we investigate the length dependence of linear and nonlinear optical properties of finite-length BN nanotubes. The recently predicted smallest BN(5,0) nanotube with configuration stabilization is selected as an example. The energy gap and optical gap show the obvious length dependence with the increase of nanotube length. When the length reaches about 24 {\AA}, the energy gap will saturate at about 3.2 eV, which agrees well with the corrected quasi-particle energy gap. The third-order polarizabilities increase with the increase of tube length. Two-photon allowed excited states have significant contributions to the third-order polarizabilities of BN(5,0) nanotube.     

非相干背景光辐照对LiNbO3∶Fe与LiNbO3∶Fe∶In晶体中二波耦合的控制

理论分析和实验观测了非相干背景光辐照下掺杂LiNbO₃晶体中的二波耦合,发现非相干背景光能够在很大范围内灵活有效地控制信号光增益,抑制扇形效应,提高信噪比,缩短光栅的建立时间.入射光光强比一定时,适当地增大背景光光强可以使光栅响应时间减小一个数量级.尤其对于抽运光光强远大于信号光光强的情况下,上述作用更为明显. 关键词： 光折变 二波耦合 非相干背景光     

喹啉氧基乙酰胺型配体镉配合物的合成、晶体结构及荧光性质

合成并通过单晶衍射表征了一个配合物[CdL(H₂O)(NO₃)]NO₃·CH₃COCH₃ (1)(L=N-甲基N-苯基-2-(8-喹啉氧基)乙酰胺)。在配合物1中,金属镉离子采取扭曲的八面体配位构型。来自配体L的1个氧原子和2个氮原子,2个硝酸根的2个氧原子及配位水分子的1个氧原子与中心镉离子配位。配合物通过分子间的O-H…O氢键作用构筑成沿a轴的一维链状结构。乙腈溶液中配体L和配合物1均在390 nm有荧光发射,但配合物的荧光强度要远低于配体。     

两个喹啉氧基乙酰胺的镧系（La、Pr）配合物的合成、表征及荧光性质

合成并通过单晶衍射表征了2个稀土配合物[LnL2(NO3)(H2O)2](NO3)2·nH2O(L=N-苯基-2-(8-喹啉氧基)乙酰胺,Ln=La(Ⅲ),n=0,1;Pr(Ⅲ),n=1,2)。在每个配合物中,十配位的稀土离子采取扭曲的双帽四方反棱柱配位构型,分别与来自2个配体的4个氧原子和2个氮原子,来自1个双齿配位硝酸根的2个氧原子及来自2个配位水分子的2个氧原子配位。乙腈溶液中,配合物发射强荧光。