自由空间量子通讯实验中纠缠源的研制

设计了适合自由空间量子通讯实验的纠缠源. 纠缠光子对的单模光纤搜集率约为每秒20000对,水平竖直方向的纠缠对比度大于95%,正负45°方向的纠缠对比度大于90%. 在本地得到了大于100个标准偏差的Bell 不等式破缺. 满足20 km量级的自由空间量子通讯试验要求. 关键词： 纠缠光子对 位相匹配 收集效率 贝尔不等式     

Pt/Ti Electrodes of PZT Thin Films Patterning by Novel Lift-Off Using ZnO as a Sacrificial Layer

We achieve a successful novel lift-off of patterning Pt/Ti electrodes on SiO2/Si substrates by employing ZnO sacrificial layer deposition and patterning, successive uniform Pt/Ti deposition and final lift-off. Then we deposit PZT thin films on the electrodes. Compared with the conventional lift-off processes for the electrodes, this novel process does not need post-annealing, which must be performed after conventional lift-off process. It is demonstrated that the electrodes patterned by the novel lift-off process have stronger adhesion. The electrodes and the PZT films on the electrodes are more compact and smoother than those by the conventional lift-off process.     

X射线衍射增强成像中的定量测量

提出了一种基于X射线衍射增强成像(DEI)断层计算机X射线层析术(CT)图像的物体尺寸精确测量方法.X射线衍射增强成像是一种基于相位衬度的成像技术.通过建立DEI的简化模型,研究衍射成像过程中品体转角、投影图像谷点位置、成像系统等效模糊等因素之间关系,由此具体探讨了系统模糊效应对圆物体边界成像带来的位置偏移,并以圆形被测样品为例.提出可精确测定直径的简单有效算法.通过理论仿真模型数据和北京同步辐射装置上的实测数据验证了该算法的精度.该方法实现了利用DEI图像对被测物体几何尺寸的精确测量,可用于对牛物组织样品等物体内部微小结构的尺寸的精确测量.     

火灾烟雾颗粒凝并分形特性研究

火灾烟雾颗粒因布朗运动由初期的主粒子凝并形成大颗粒的凝团结构，其外形呈现出分形特征，根据分形理论对火灾烟雾颗粒凝团结构进行分析研究，采用场发射扫描电镜对多种材料的烟雾颗粒图像进行测试，通过对烟雾凝团图像进行处理，获得了火灾探测中常见的多种材料的分形维数和分形系数，给出了烟雾颗粒的主粒子粒径，并对其影响因素进行了对比分析，为火灾烟雾探测中颗粒凝并分形特性研究提供有益的探索. 关键词： 火灾 烟雾 颗粒 凝并 分形     

Bipolar Electrochemistry Exfoliation of Layered Metal Chalcogenides Sb2S3 and Bi2S3 and their Hydrogen Evolution Applications

Efficient exfoliation and downsizing of Sb₂S₃ and Bi₂S₃ layered compounds by using scalable bipolar electrochemistry on their suspensions in aqueous media are here demonstrated. The resulting samples were characterized in detail by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy; their electrochemistry toward hydrogen evolution was also investigated. Hydrogen evolution ability of exfoliated Sb₂S₃ and Bi₂S₃ was investigated and compared to the bulk counterparts.     

Polypyrrole modified hierarchical porous CoS2@RGO aerogel electrode for ultrafast sodium storage

Journal of Solid State Electrochemistry - CoS2 nanooctahedrons homogeneously encapsulated by hierarchical porous-reduced graphene oxide and polypyrrole thin film are constructed via a simple...     

Gravitational wave imprint of new symmetry breaking

It is believed that there are more fundamental gauge symmetries beyond those described by the Standard Model of particle physics. The scales of these new gauge symmetries are usually too high to be reachable by particle colliders. Considering that the phase transition (PT) relating to the spontaneous breaking of new gauge symmetries to the electroweak symmetry might be strongly first order, we propose considering the stochastic gravitational waves (GW) arising from this phase transition as an indirect way of detecting these new fundamental gauge symmetries. As an illustration, we explore the possibility of detecting the stochastic GW generated from the PT of begin{document}$ {bf{B}}-{bf{L}}$end{document} in the space-based interferometer detectors. Our study demonstrates that the GW energy spectrum is reachable by the LISA, Tianqin, Taiji, BBO, and DECIGO experiments only for the case where the spontaneous breaking of begin{document}$ {bf{B}}-{bf{L}}$end{document} is triggered by at least two electroweak singlet scalars.     

Corrosion resistance and blood compatibility of lanthanum ion implanted pure iron by MEVVA

Pure iron is a potential material applying for coronary artery stents based on its biocorrodible and nontoxic properties. However, the degradation characteristics of pure iron in vivo could reduce the mechanical stability of iron stents prematurely. The purpose of this work was to implant the lanthanum ion into pure iron specimens by metal vapor vacuum arc (MEVVA) source at an extracted voltage of 40 kV to improve its corrosion resistance and biocompatibility. The implanted fluence was up to 5 × 10¹⁷ ions/cm². The X-ray photoelectron spectroscopy (XPS) was used to characterize the chemical state and depth profiles of La, Fe and O elements. The results showed lanthanum existed in the +3 oxidation state in the surface layer, most of the oxygen combined with lanthanum and form a layer of oxides. The lanthanum ion implantation layer could effectively hold back iron ions into the immersed solution and obviously improved the corrosion resistance of pure iron in simulated body fluids (SBF) solution by the electrochemical measurements and static immersion tests. The systematic evaluation of blood compatibility, including in vitro platelets adhesion, prothrombin time (PT), thrombin time (TT), indicated that the number of platelets adhesion, activation, aggregation and pseudopodium on the surface of the La-implanted samples were remarkably decreased compared with pure iron and 316L stainless steel, the PT and TT were almost the same as the original plasma. It was obviously showed that lanthanum ion implantation could effectively improve the corrosion resistance and blood compatibility of pure iron.