C60和C60／C70的激光脱附飞行时间质谱分析

采用激光脱附并直接测量离子的方法对实验室提取的C_(60)/C_(70)以及进一步分离得到的纯C_(60)进行了飞行时间质谱分析,并讨论了质谱分析过程中实验条件对结果的影响.     

冲击荷载下C型G550冷弯钢的断裂机理研究

以C型G550薄壁冷弯钢构件为研究对象, 通过材料在不同应变率下的拉伸实验和数值模拟数据得到Johnson-Cook (J-C)本构模型和Johnson-Cook失效模型参数. 通过Abaqus软件模拟了不同冲击荷载作用下C型冷弯钢构件撕裂破坏的全过程, 利用落锤装置轴向冲击试验进行对比, 其实验结果与有限元数值模拟结果有良好的一致性. 此外, 对冲击试样撕裂断口进行微观形貌分析, 得到构件的断裂机理. 结果表明: 随着冲击速度的提高, 冲击力对构件的加载时间增加, 构件需要较大的塑性变形来吸收冲击能量; 冲击速度越高, 裂纹扩展功所占吸收冲击能量的比例越大, 显示出高速下裂纹扩展的能力越好; 冲击速度较高时, 以脆性断裂为主, 断口出现解理面, 甚至在高速变形时发生了绝热剪切破坏.     

多模玻色二次多项式型系统的特性函数和准概率分布函数

运用多模玻色系统广义线性量子变换的普遍理论，对多模玻色二次多项式型系统进行了研究.给出了多模玻色二次多项式型系统的正规、反正规、Wigner特性函数、P表示和Q表示.举例讨论了该系统的压缩性质. 关键词： 多模玻色二次多项式型系统 特性函数 准概率分布函数     

Resolution enhancement with improved range Doppler algorithm in high numerical aperture OCT

The improved range Doppler algorithm is proposed to abate the trade-off between resolutions and depth of focus in spectral domain optical coherence tomography.By considering the finite beam width and the shape of the wavefronts produced by the Gaussian beam,a physical diffraction model is presented to simulate the light propagation process in the sample.The two-dimensional processing of the spectrum data is decomposed into two one-dimensional processings of Stolt transform and matched filter.Experimental results show that image reconstruction can be achieved.The transverse and axial resolutions are both improved significantly,especially in the out-of-focus range,and the resolutions are almost equivalent throughout the entire region of interest.     

HZ associated production with decay in the Alternative Left-Right Model at CEPC and future linear colliders

In this study, Higgs and Z boson associated production with subsequent decay is attempted in the framework of alternative left-right model, which is motivated by superstring-inspired E_6 model at CEPC and future linear colliders. We systematically analyze each decay channel of Higgs with theoretical constraints and latest experimental methods. Due to the mixing of scalars in the Higgs sector, charged Higgs bosons can play an essential role in the phenomenological analysis of this process. Even though the predictions of this model for the signal strengths of this process are close to the standard model expectations, it can be distinct under high luminosity.     

导弹目标单、双基地雷达散射截面对比分析

目标单、双基地雷达散射截面(RCS)反映了目标是否容易被单、双基地雷达检测到。目前缺乏单、双基地RCS对比的量化指标。首先定义了双基地RCS相对于单基地RCS的RCS增强因子和RCS增强率,然后应用该定义统计分析了某隐身目标和非隐身目标双基地RCS计算结果。结果显示：对隐身目标,RCS增强因子大,RCS增强率高,对于非隐身目标,其RCS增强因子显著下降,RCS增强率不高。结合指标含义,应用双基地RCS有助于隐身目标检测,而对非隐身目标效果并不明显,这与雷达界认识相一致。这也说明,应用上述两个指标进行单、双基地RCS对比分析是有效的。此外根据隐身目标在较窄双基地角范围内的双基地RCS分析结果,应用双基地角20°~40°范围内的双基地RCS即可提高对隐身目标的检测效果。     

All-angle broadband negative refraction of metal waveguide arrays in the visible range: theoretical analysis and numerical demonstration

In this Letter, we introduce a simple metal waveguide array for realizing all-angle wide frequency bandwidth negative refraction from the visible to infrared frequencies. Theoretical analysis from the rigorous coupled-wave theory reveals that the negative coupling constant resulting from the anomalous coupling of guided surface plasmon polariton modes contributes to the negative refraction. The analytical results are confirmed by finite-difference time-domain numerical simulations. Our result provides an alternative way to construct robust all-angle negative refractive materials operating in a wide range of frequency from the near-infrared to the visible range.     

基于Contourlet域隐马尔可夫树模型的图像融合算法

本文提出一种基于Contourlet域隐马尔可夫树(HMT)模型的图像融合算法。由于Contourlet变换能克服小波变换在处理高维信号时的不足,它比小波变换具有更好的方向性、较高的逼近精度和更好的稀疏表达性能。而HMT模型能有效捕获尺度间、尺度内的contourlet系数特性。因此将Contourlet域HMT模型应用于图像融合领域,能充分挖掘数据之间的相关性,更好的提取图像边缘特征,为融合提取更多的特征信息。实验结果表明本文的算法获得的融合图像视觉效果良好,是一种有效且可行的融合算法。     

Ultraviolet wave plates based on monolithic integration of two fully filled and planarized nanograting layers

We successfully fabricated a high-performance half-wave plate for the 405 nm wavelength based on monolithic integration of two nanograting layers. Each of the nanograting layers functions as a quarter-wave plate. Both of the nanograting layers were fully filled and planarized to achieve the monolithic integration. UV-nanoimprint lithography, along with thin-film deposition, high-aspect-ratio reactive ion etching, and trench-filling technologies, was used in fabrication and integration of the individual nanograting layers. High-aspect-ratio nanogratings with sub-50 nm linewidths and 100 nm spacing were fabricated to achieve good optical performance at the near-UV wavelength. The ability to integrate multiple nanostructure-based optical layers opens a path for integrated multifunction devices, as well as a new strategy for driving both miniaturization and cost.     

Temperature dependence of surface and structure properties of ZnCdO film

Zn1-xCdx O films are grown on c-sapphire substrates by laser molecular beam epitaxy(LMBE) at different temperatures. Their crystallographic structures, compositions, surface electronic structures are investigated. The a-axis lattice constant of Zn0.95Cd0.05 O is 3.20. Moreover, the epitaxial relationship shows a 30°-in-plane rotation of the film with respect to the c-sapphire substrate. When the substrate temperatures arrives at 500℃, the in situ reflection high-energy electron diffraction(RHEED) pattern of Zn Cd O film shows sharp streaky pattern. The maximum Cd content of Zn Cd O film grown at low substrate temperatures increases up to about 29.6 at.%, which is close to that of the ceramic target. In situ ultraviolet photoelectron spectroscopy(UPS) measurements demonstrate that Zn Cd O film exhibits intense peaks at 4.7 e V and 10.7 e V below the Fermi level, which are assigned to the O 2p and Zn 3p states. Energetic distance between Zn 3d and Cd 4d is 0.60 e V. Above 470 nm, the thin film shows excellent optical transmission.