平面ISODYNE法及其在复合材料力学中的应用

由J. T. Pindera提出的平面isodyne法是散光法的一种发展。具有非破坏性直接测取受力物体内部应力的特点。不需要大功率的激光器,条纹清晰,无畸变,对于平面应力问题可以得到应力分量的全部信息。在复合材料力学、断裂力学和接触问题等领域有广泛的应用前景。文章闸述了该方法的原理和技术,并应用它得到一受三点弯曲荷载的有裂纹的复合材料梁粘结层的应力分布。     

Investigations on quantum correlation of coupled qubits in squeezed vacuum reservoir

In this paper, we investigate the quantum correlation of coupled qubits which are initially in maximally entangled mixed states in squeezed vacuum reservoir. We compare and analyse the effects of squeezed parameters on quantum discord and quantum concurrence. The results show that in squeezed vacuum reservoir, the quantum discord and quantum concurrence perform completely opposite behaviors to the change of squeezed parameters. Quantum discord survives longer with the increase of squeezed amplitude parameter, but entanglement death turns faster on the contrary. The results also indicate that the classical correlation of the system is smaller than quantum discord in vacuum reservoir, while it is bigger than quantum discord in squeezed vacuum reservoir. The quantum discord and classical correlation are more robust than quantum concurrence in the two reservoir environments, which indicates that the entanglement actually is easily affected by decoherence and quantum discord has stronger ability to avoid decoherence in squeezed vacuum reservoir.     

下电极对ZnO薄膜电阻开关特性的影响

本文采用直流磁控溅射法在三种不同的下电极(BEs)上制备了ZnO薄膜, 获得了W/ZnO/BEs存储器结构. 研究了不同的下电极材料对器件电阻开关特性的影响. 研究结果表明, 以不同下电极所制备的器件都具有单极性电阻开关特性. 在低阻态时, ZnO薄膜的导电机理为欧姆传导, 而高阻态时薄膜的导电机理为空间电荷限制电流. 不同下电极与ZnO薄膜之间的肖特基势垒高度对电阻开关过程中的操作电压有较大的影响, 并基于导电细丝模型对不同下电极上ZnO薄膜的低阻态阻值及reset电流的变化进行了解释. 关键词： ZnO薄膜 电阻开关 下电极     

一种基于运动式发射天线的光学接收天线设计

设计一款应用于多发射天线多接收天线自由空间激光通信系统中的折射式光学接收天线。天线焦距120.02 mm,相对孔径1∶1.13,工作波长为850 nm,波长范围覆盖820 nm ~880 nm,在50 lp/mm频率处0视场的MTF为0.5。接收天线可以在发射天线移动48 mm范围内利用光敏面直径为0.5 mm的雪崩光电二极管（APD）接收3 mrad发散角的光信号。该天线由两组、共4片球面透镜组成,结构简单,可实现对运动式发射天线的光信号的接收。     

金属熔体黏度与结构相关性的分子动力学模拟

运用EAM(embed atom method)作用势，采用非平衡分子动力学模拟获得Al熔体的偶分布函数与黏度数值随温度的变化曲线，偶分布函数的计算结果与实验值符合得较好.对模拟所得到的黏度数据编程实现黏度的Arrhenius公式拟合，得到激活能E.并利用模拟所得到的黏度值及激活能对Lennard-Jones(L-J)作用势进行修正，获得黏度与偶分布函数及原子间相互作用势之间的关系式，两条黏度拟合曲线与分子动力模拟结果符合得比较好，说明拟合程序的编写是比较成功的，实现了对L-J作用势的修正.该研究为金属及合金原子间相互作用势的建立提供了新的思路. 关键词： 非平衡分子动力学模拟 L-J作用势修正 Al熔体 结构与黏度相关性     

Spontaneous formation of bags with negative surface energy

We demonstrate within the Ginzburg-Landau model of a confining medium that the surface energy associated with the interface between the normal and the confining phases can be negative, and briefly discuss some consequences of this fact.Dedicated to the memory of M. Gmitro.This work was done at the Niels Bohr Institute Copenhagen, and put into its final form at the Institute of Theoretical Physics, of University of Regensburg. I thank both institutes for their generous hospitality and Professors Poul Olesen and Wolfram Weise for discussions.     

The luminescence efficiency of YAG: Ce phosphors

The luminescence intensity of Yttrium aluminium garnet activated by the Ce³⁺ (YAGCe³⁺) under cathode-ray excitation depends on the preparation method and content of some dopants. Samples containing Fe, Pt, Ir or some colour centre, respectively, show relatively low luminescence. The maximum luminescence intensity was obtained with the Czochralski method grown single crystals in 98% Ar+2% H₂ atmosphere which were sensitized by oxygen annealing followed by treatment at 1500 °C in molybdenum container using a wet hydrogen atmosphere.     

Learning Visible Thermal Person Re-Identification via Spatial Dependence and Dual-Constraint Loss

Visible thermal person re-identification (VT Re-ID) is the task of matching pedestrian images collected by thermal and visible light cameras. The two main challenges presented by VT Re-ID are the intra-class variation between pedestrian images and the cross-modality difference between visible and thermal images. Existing works have principally focused on local representation through cross-modality feature distribution, but ignore the internal connection of the local features of pedestrian body parts. Therefore, this paper proposes a dual-path attention network model to establish the spatial dependency relationship between the local features of the pedestrian feature map and to effectively enhance the feature extraction. Meanwhile, we propose cross-modality dual-constraint loss, which adds the center and boundary constraints for each class distribution in the embedding space to promote compactness within the class and enhance the separability between classes. Our experimental results show that our proposed approach has advantages over the state-of-the-art methods on the two public datasets SYSU-MM01 and RegDB. The result for the SYSU-MM01 is Rank-1/mAP 57.74%/54.35%, and the result for the RegDB is Rank-1/mAP 76.07%/69.43%.