Complex-amplitude-based phase unwrapping method for digital holographic microscopy

A complex-amplitude-based phase unwrapping approach for digital holographic microscopy is proposed in this paper. A quality map is derived directly from the reconstructed complex amplitude distribution of object wave to evaluate noise influence and phase reliability in the wrapped phase image. Quality-guided phase unwrapping algorithm is then implemented with the quality map to retrieve continuous phase profile. Unwrapping errors caused by unreliable phase data are successfully suppressed. The effectiveness of this method is demonstrated with simulation and experimental results.     

Structural,electronic, and optical absorption properties of TiO2 nanotube adsorbed with Cu n clusters

The structural,electronic,and optical absorption properties of TiO2 nanotube(TiO2NT)with Cun clusters(n=1–4)adsorbed on its surface have been investigated based on density functional theory calculations.The TiO2NT is constructed by rolling up a(101)sheet of anatase TiO2 around the[1 01]direction;the ground states of Cun/TiO2NT systems are determined by analyzing the average adsorption energies.Calculation results show that odd-even oscillations occur for the average adsorption energy,the Cu–O bond length,and the amount of transferred electrons,with the increase in Cun cluster size;and the Cun/TiO2NTs with odd n’s demonstrate stronger interaction between the Cun cluster and the TiO2NT.Also,the impurity states introduced by the Cun cluster to the band gap of TiO2NT cause an obvious redshift of the optical absorption spectrum toward the visible light region,especially for the even n cases.     

Toeplitz operators on Fock-Sobolev spaces with positive measure symbols

We discuss Toeplitz operators on Fock-Sobolev space with positive measure symbols.By FockCarleson measure,we obtain the characterizations for boundedness and compactness of Toeplitz operators.We also give some equivalent conditions of Schatten p-class properties of Toeplitz operators by Berezin transform.     

Quantum entanglement swapping of two arbitrary biqubit pure states

In this paper, the issue of swapping quantum entanglements in two arbitrary biqubit pure states via a local bipartite entangledstate projective measure in the middle node is studied in depth, especially with regard to quantitative aspects. Attention is mainly focused on the relation between the measure and the final entanglement obtained via swapping. During the study, the entanglement of formation (EoF) is employed as a quantifier to characterize and quantify the entanglements present in all involved states. All concerned EoFs are expressed analytically; thus, the relation between the final entanglement and the measuring state is established. Through concrete analyses, the measure demands for getting a certain amount of a final entanglement are revealed. It is found that a maximally entangled final state can be obtained from any two given initial entangled states via swapping with a certain probability; however, a peculiar measure should be performed. Moreover, some distinct properties are revealed and analyzed. Such a study will be useful in quantum information processes.     

Novel internal photoemission in manganite/ZnO heterostructure

Science China Chemistry - A novel photovoltaic phenomenon of internal photoemission was found in a low cost manganite La0.62Ca0.29K0.09MnO3 (LCKMO)/zinc oxide (ZnO) heterojunction bilayers grown on...     

Reconstruction of bandlimited signal from its non-uniform integral samples

In this article, we discuss the problem of reconstructing a bandlimited signal f from the samples of the integral of the signal. We first apply the trigonometric polynomials to approximate the integral of the signal and then reconstruct instantaneous samples from the signal integral.     

Preparation and luminescent properties of Eu-doped transparent glass-ceramics containing SrF2 nanocrystals

Transparent glass-ceramics containing SrF₂ nanocrystals were fabricated by melt-quenching and subsequent heating of glass with a composition of 50SiO₂–10Al₂O₃–20ZnF₂–20SrF₂. X-ray diffractometry, transmission electron microscopy, and energy dispersive spectroscopy were used to investigated the microstructure of the SrF₂ glass-ceramics. Results show that SrF₂ nanocrystals were homogeneously precipitated among the aluminosilicate glass matrix, and the mean size of the SrF₂ nanocrystals was about 20 nm, and Eu³⁺ ions partition mainly into the precipitated SrF₂ nanocrystals after crystallization. The glass-ceramics exhibited intense red emission corresponding to the ⁵D₀ → ⁷F_J (J = 0–4) transitions of Eu³⁺ ions under 393 nm excitation. A significant Eu³⁺ luminescence enhancement by a factor of about nine times was observed after crystallization. Besides, the obvious stark splitting emissions, the low forced electric dipole ⁵D₀ → ⁷ F₂ transition, and the long decay lifetimes of Eu³⁺ ions also revealed the partition of Eu³⁺ ions into low phonon energy SrF₂ nanocrystals. Our results indicate the SrF₂ based fluorosilicate glass-ceramics is an excellent host for trivalent lanthanide ion doping and may find applications in photonics.     

Fatigue crack growth in fiber-metal laminates

Fiber-metal laminates(FMLs)consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg,and it(it means FMLs)is laminated by Al alloy and fiber alternatively.Fatigue crack growth rates in notched fiber-metal laminates under constant amplitude fatigue loading were studied experimentally and numerically and were compared with them in monolithic 2024-T3 Al alloy plates.It is shown that the fatigue life of FMLs is about 17 times longer than monolithic 2024-T3 Al alloy plate;and crack growth rates in FMLs panels remain constant mostly even when the crack is long,unlike in the monolithic 2024-T3 Al alloy plates.The formula to calculate bridge stress profiles of FMLs was derived based on the fracture theory.A program by Matlab was developed to calculate the distribution of bridge stress in FMLs,and then fatigue growth lives were obtained.Finite element models of FMLs were built and meshed finely to analyze the stress distributions.Both results were compared with the experimental results.They agree well with each other.     

纤维光锥有效透过率的理论分析

光锥的有效透过率不仅影响光锥与CCD的耦合效率,而且会影响到耦合器件的信噪比.本文主要从理论上讨论了影响光锥有效透过率性能的因素,从纤维光学元件的实际内部结构推导出了其实际有效填充率,从光线在光锥中的传输特征推导出了光线在光锥中传播时产生的衰减损耗,最后提出了提高光锥有效透过率的方法和途径.     

基于高分辨质谱在线观测的2011深圳大运会前后PM_1化学组成与粒径分布

本文利用先进的高分辨飞行时间气溶胶质谱仪（HR-ToF-AMS）于2011年深圳世界大学生运动会前后（2011年8月3日~9月22日）对深圳市区大气亚微米细粒子（PM1）化学成分和粒径分布进行了在线测量.结果表明,整个观测期间PM1质量浓度平均为51.1±32.6gm3,其中有机物占颗粒物总质量的37.9%,硫酸盐为37.1%,铵盐11.9%,黑碳6.6%（由一台单颗粒黑碳光度计（SP2）单独测量）,硝酸盐5.8%,氯化物0.6%.观测期间各成分（除黑碳外）的粒径分布峰值位于真空动力学粒径550nm附近,而有机物在较小粒径范围（100~200nm）仍有较多质量分布,显示出本地一次源的明显贡献.基于高分辨有机质谱计算得到的有机气溶胶的平均元素组成为：碳34.0%、氢53.2%、氧12.0%和氮0.8%（原子个数百分比）,对应的OM/OC（有机物与有机碳质量比）平均值为1.66±0.16.采用正矩阵因子解析（PMF）模型对有机气溶胶高分辨质谱进行因子解析,得到三类有机气溶胶：HOA（还原态有机气溶胶）,SV-OOA（半挥发氧化态有机气溶胶）和LV-OOA（低挥发氧化态有机气溶胶）,分别占有机物总量的31.3%,39.8%和28.9%,说明二次有机气溶胶（以SV-OOA和LV-OOA之和代表）是有机气溶胶的主体部分.结合气团来源分析不同时段PM1化学组成和粒径分布特征表明,大运会召开期间PM1质量浓度水平比整个观测期间的平均值低60.7%,是气团来自洋面等有利气象条件和黄标车限行等污染源控制措施的综合作用结果.