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941.
We have demonstrated super quasi-phase matching (QPM) in a super periodically poled lithium niobate (PPLN), which is composed of multiple ordinary PPLN cells. When super QPM is achieved, the slight phase mismatch in each PPLN cell can be further compensated for, and the relevant second harmonic generation is facilitated greatly. This mechanism provides an insightful means to relieve the limitation imposed by sample fabrication inaccuracy and will open up a promising avenue toward highly efficient nonlinear interactions. 相似文献
942.
943.
Ping Guo Lin ZhengJi Ming Zheng Ruizhi ZhangLuna Yang Zhaoyu Ren 《Applied Surface Science》2011,258(2):705-710
A plane-wave density functional theory (DFT) calculations have been performed to investigate structural and electronic properties of TaSin (n = 1-3, 12) clusters supported by graphene surface. The resulting adsorption structures are described and discussed in terms of stability, bonding, and electron transfer between the cluster and the graphene. The TaSin clusters on graphene surface favor their free-standing ground-state structures. Especially in the cases of the linear TaSi2 and the planar TaSi3, the graphene surface may catalyze the transition of the TaSin clusters from an isomer of lower dimensionality into the ground-state structure. The adsorption site and configuration of TaSin on graphene surface are dominated by the interaction between Ta atom and graphene. Ta atom prefers to adsorb on the hollow site of graphene, and Si atoms tend to locate on the bridge site. Further, the electron transfer is found to proceed from the cluster to the surface for n = 1 and 2, while its direction reverses as n > 2. For the case of TaSi, chemisorption is shown to prevail over physisorption as the dominant mode of surface-adsorbate interaction by charge density analysis. 相似文献
944.
Yan-Huai Ding Ping ZhangHu-Ming Ren Qin ZhuoZhong-Mei Yang Xu JiangYong Jiang 《Applied Surface Science》2011,258(3):1077-1081
Surface adhesion properties are important to various applications of graphene-based materials. Atomic force microscopy is powerful to study the adhesion properties of samples by measuring the forces on the colloidal sphere tip as it approaches and retracts from the surface. In this paper we have measured the adhesion force between the colloid probe and the surface of graphene (graphene oxide) nanosheet. The results revealed that the adhesion force on graphene and graphene oxide surface were 66.3 and 170.6 nN, respectively. It was found the adhesion force was mainly determined by the water meniscus, which was related to the surface contact angle of samples. 相似文献
945.
946.
We carry out a systematic study on the fusion-fission and evaporation residue excitation functions for the reactions of 6,7Li, 9Be, 10,11B + 209Bi and 6,9Li, 9Be + 208Pb, in which the projectiles are loosely bound and have low threshold energies against breakup. The fusion cross sections are calculated by the coupled-channel model. The compound nuclei decay are analyzed with the standard statistical model. The fission and evaporation residue excitation functions are well reproduced by our calculations, proving the validity of the standard statistical model in describing the compound nuclei decay in these characteristic reactions. For the compound nuclei with A=215-220 and Z=86-88, the liquid drop fission barriers need to be scaled by 0.80-1.02 to reproduce the experimental data. And a decreasing trend of the scaling factor with increasing fissionability parameter Z2/(50A) is found. 相似文献
947.
Ying Li Gaoyang Zhao Jian Su Erfeng Shen Yang Ren 《Applied Physics A: Materials Science & Processing》2011,104(4):1069-1073
Top electrode (TE) material on the resistive switching behavior of (TE)/CuO/SnO2:F/Si substrate has been studied. We investigated the switching properties of CuO films deposited by sol-gel process. Two
kinds of top electrode (TE) material on the resistive switching behaviors have been studied. The nonpolar and bipolar resistive
switching phenomenon was observed in CuO thin films with different top electrodes. The filamentary mechanism was used to explain
the two kinds of resistive switching behaviors. For the Pt/CuO/ATO device, it showed the nonpolar resistive switching where
conducting path is formed and disappear due to the oxygen vacancy. For the Cu/CuO/ATO device, the resistance reduction is
due to the existing Cu to form conduction Cu-rich pathways. An opposite bias takes the existing Cu back to the Cu electrode
to its high-resistance state. CuO thin films are also observed by XRD, AFM and XPS. 相似文献
948.
视场角(FOV)是仅次于最大光程差、决定高分辨率傅里叶红外光谱仪(FTIRS)仪器线型函数(ILS)的重要因素.由于光学设计和装调原因,理论为圆形FOV的扩散光束,到达探测器端时,其水平和垂直方向上的FOV值往往不再严格对等.对此,提出了以椭圆形面光源取代传统文献中的圆形面光源来反映这种非对等性,并结合最大光程差参数,... 相似文献
949.
本文从FPGA器件内部最基本的CMOS单元出发,分析了器件功能失效时反相器输出波形随累积剂量的变化关系,进而研究Altera SRAM型FPGA器件60Co γ射线辐照后的总剂量辐射损伤效应.实验结果表明:由于场氧漏电和结构漏电的影响,随着累积剂量的增加输出波形发生畸变,峰峰值变为原来的十分之一左右,但输出波形还有相对的高低电平;同时,输出高电平不能保持原有的状态,迅速地向低电平转换,并且转换速度随着累积剂量的增加而加快,输出低电平相对初始值有一定程度抬高;由于栅氧厚度变薄,输出波形
关键词:
60Coγ')" href="#">60Coγ
总剂量辐射损伤效应
SRAM型FPGA
CMOS单元 相似文献
950.
In this paper we study polynomial normal forms and smooth (C∞) classification of one kind of diffeomorphisms which have infinite many resonant relations but are finitely determined. We derive a complete list of normal forms of all such germs with arbitrary degeneracy of their nonlinear parts. 相似文献