Quantum key distribution by comparing Bell states

We propose a quantum key distribution (QKD) scheme based on entanglement swapping. In this scheme, the methods to form secret keys are so interesting. By comparing initial Bell state and outcome of entanglement swapping, the secret keys between Alice and Bob are generated involuntarily.     

Free control of far-field scattering angle of transmission terahertz wave using multilayer split-ring resonators’ metasurfaces

To enhance transmission efficiency of Pancharatnam–Berry (PB) phase metasurfaces, multilayer splitring resonators were proposed to develop encoding sequences. As per the generalized Snell’s law, the deflection angle of the PB phase encoding metasurfaces depends on the metasurface period’s size. Therefore, it is impossible to design an infinitesimal metasurface unit; consequently, the continuous transmission scattering angle cannot be obtained. In digital signal processing, this study introduces the Fourier convolution principle on encoding metasurface sequences to freely control the transmitted scattering angles. Both addition and subtraction operations between two different encoding sequences were then performed to achieve the continuous variation of the scattering angle. Furthermore, we established that the Fourier convolution principle can be applied to the checkerboard coded metasurfaces.     

EMBEDDED 2-SPHERES IN INDEFINITE 4-MANIFOLDS

51.IntroductionOne0ftheinterestingproblemsneartheheartof4dimensionaltopologyistodecidewhich2-dimensionalhomology/homotoPyclasscanberepresentedbyasmo0thlyembedded2-sphereinagivensmooth4-dimensionalmanifold.ItwasRohlin[19]wh0pointed0utintheearly195Ostousthatnotevery2-dimensionalhthmology/hom0topyclasscanbesorepresented.TheimportanceoftheproblemwasexplainedbyKervaireandMilnorl11].Onedecadelater,theystartedthestudyin1961,followedbyBoardm..I1]?Wall[25]5Tri.t..m[23]tHsiangandSzczarba[1o],andRoh…     

偏磷酸根(PO-3)对氟铝酸盐玻璃透光性能影响

在氟铝酸盐玻璃（AMCSBY）中引入Ba(PO3）2替代BaF2,替代公式为10MgF2-20CaF2-(10-x)BaF2-10SrF2-15YF3-35AlF3-xBa(PO3)2(x=,2,4,6,8)。对玻璃进行了差热分析，结果表明，在氟铝酸盐玻璃中引入偏磷酸盐使玻璃形成能力大大提高；测量了玻璃从紫外到红外的透过光谱和紫外吸收光谱，在玻璃中引入偏磷酸钡使玻璃中红外透过能力下降，红外吸收边带移向短波段，玻璃紫外透过能力得到提高。紫外吸收边带移向紫外波段，由于PO3^-的影响，O－H吸收峰由2830nm移到3145nm。     

Crystallization of Ge2Sb2Te5 phase—change optical disk media

In this paper, the crystallization behaviour of amorphous Ge₂Sb₂Te₅ thin films is investigated using differential scanning calorimetry), x-ray diffraction and optical transmissivity measurements. It is indicated that only the amorphous phase to face-centred-cubic phase transformation occurs during laser annealing of the normal phase-change structure, which is a benefit for raising the phase-change optical disk's carrier-to-noise ratio (CNR). For amorphous Ge₂Sb₂Te₅ thin films, the crystallization temperature is about 200℃ and the melting temperature is 546.87℃. The activation energy for the crystallization, E_a, is 2.25eV. The crystallization dynamics for Ge₂Sb₂Te₅ thin films obeys the law of nucleation and growth reaction. The sputtered Ge₂Sb₂Te₅ films were initialized by an initializer unit. The initialization conditions have a great effect on the reflectivity contrast of the Ge₂Sb₂Te₅ phase-change optical disk.     

A study on the short—wavelength and high—numerical—aperture phase—change recording

In this paper, we discuss the phase-change recording at a short-wavelength (514nm) and a high numerical aperture (0.85). Effects of recording power and pulse width on the size of the recording marks are studied. The minimum recording mark with a length of approximately 220nm has been observed. The capacity of about 17GB for a single-layer disc of a 12cm diameter can be obtained. The maximum carrier-to-noise ratio reaches 45dB at a writing power of 13--14mW.     

Simulation of current spreading for GaN-based light-emitting diodes

Uniform current spreading is crucial for the performance of light-emitting diodes (LEDs). It has been reported that the reliability and light distribution are affected by non-uniform current spreading. In this paper, the impact of different electrode patterns on the performance of LED chips is investigated. A hybrid modeling method is employed to analyze the electrical and thermal characteristics of LEDs with two different electrode mesa structures. Corresponding experiments are also carried out to validate the calculation results. It is found that increasing amount of p-electrodes in interdigitated electrode patterns is effective in improving the performance of LEDs.     

有机薄膜光盘的微区结构

通过光学显微镜（ＯＭ）扫描电镜（ＳＥＭ）和扫描隧道显微镜（ＳＴＭ）观察了光记录有机薄膜的微区结构，从微区结构的形貌可以看出光记录后酞菁薄膜上产生了鼓泡，通过这些观察方法的比较发现扫描隧道显微镜可以提供更加详细，精确的三维参数，薄膜的微区结构研究对于分析光盘的性能，了解记录机理具有重要意义。     

周期性磁谐振材料本构参数的理论分析

将薄的磁谐振介质板等效为面磁流, 利用周期性边界条件, 给出了面磁流的指数形式. 通过计算无穷个面磁流在不同空间位置上产生的总电场和总磁场, 推导出了周期性磁谐振人工材料的色散关系和布洛赫阻抗, 进而获取了布洛赫本构参数的理论计算公式. 由于考虑了磁谐振人工材料中的电反谐振对布洛赫介电常数和磁导率的影响, 所以基于仿真实验的布洛赫本构参数的提取值和布洛赫本构参数理论预测值之间的误差很小, 这说明本文推导的布洛赫本构参数的理论计算公式在描述周期性磁谐振材料的电磁特性方面是十分有效的. 这些理论公式将在解释磁谐振现象、设计和优化周期性磁谐振材料等方面提供重要的理论依据. 关键词： 周期性结构 磁谐振 布洛赫本构参数 面磁流