利用边缘相位校正实现光束整形的高精度优化

提出利用边缘相位校正的新方法,校正用追迹法设计的产生环形光束的衍射光学元件的相位分布,从而实现光束整形中的高精度优化。通过将高斯光束整形为环形光束,将该方法、G-S(Gerchberg-Saxton)算法和改进的G-S算法设计得到的整形结果作了比较,结果表明,G-S算法的整形结果虽然衍射效率最大,但是均方根值和最大偏差也太大;改进的G-S算法可以有效的降低均方根值和最大偏差,但衍射效率也有较大的下降;而用边缘相位校正可以在衍射效率略微下降的情况下,更大的降低均方根值和最大偏差,其整形结果是综合了衍射效率、均方根值和最大偏差这三个评价指标以后得到的最优化结果,已接近理想的环形光束。     

An example of applications of the elementary catastrophe theory in Hamiltonian systems

The convection in atmosphere discussed in ref. [1] is rigorously treated by considering the variation of environmental temperature with the height. This represents an example of applications of the elementary catastrophe theory in Hamiltonian systems.     

厚胶光刻非线性畸变的校正

利用厚胶光刻技术制作大深度微结构元件是一种有效的途径,但厚胶光刻过程中的非线性畸变对光刻面形质量的严重影响限制了该技术的应用,基于此,提出了一种对掩模透射率函数进行校正的方法。分析空间像形成及其在光刻胶内传递、曝光、显影等过程中非线性因素的影响,利用模拟退火算法对掩模透射率函数进行校正,以提高光刻面形质量,并以凹面柱透镜为例,给出了校正前后的显影轮廓模拟结果,其校正后浮雕面形的体积偏差仅为2.63%。该方法在有效改善面形质量的同时,并没有引起掩模的设计、制作难度及费用增加,这对于设计、制作高质量的微结构元件有重要意义。     

Recording Fractional Fourier Transform Hologram Using Holographic Zone Plate

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A novel imaging tool for hepatic portal system using phase contrast technique with hydrogen peroxide‐generated O2 gas

The objective of this study was to investigate the potential of hydrogen peroxide‐generated oxygen gas‐based phase contrast imaging (PCI) for visualizing mouse hepatic portal veins. The O₂ gas was made from the reaction between H₂O₂ and catalase. The gas production was imaged by PCI in real time. The H₂O₂ was injected into the enteric cavity of the lower sigmoid colon to produce O₂ in the submucosal venous plexus. The generated O₂ gas could be finally drained into hepatic portal veins. Absorption contrast imaging (ACI) and PCI of O₂‐filled portal veins were performed and compared. PCI offers high resolution and real‐time visualization of the O₂ gas production. Compared with O₂‐based ACI, O₂‐based PCI significantly enhanced the revealing of the portal vein in vivo. It is concluded that O₂‐based PCI is a novel and promising imaging modality for future studies of portal venous disorders in mice models.     

关于测定二元系中挥发组分活度系数的GLPC方法的研究

GLPC法测定二元系中挥发组分有限浓度时的活度系数曾为Chueh和Ziegler、Conder和Purnell、Chch和Parcher等所探讨,但因后续工作太少,迄今未能成熟,将这一方法得到肯定,对于研究二元溶液的热力学是有意义的,经过反复比较,我们决定对Chueh和Ziegler的方法作进一步探讨。     

黄色含硫硅酸盐类无毒新颜料的制备

研究新型无毒无机颜料,逐步取代如铅铬黄、镉黄等无机颜料,日益引人注意。我们以价廉易得的自云石凹凸棒、蒙脱石、凹凸棒石粘土矿为原料,制得黄色硅酸盐类无毒新型颜料。研究了该类颜料的骨架结构与成分,及其发色机理。工艺过程如下:     

Boosting the Efficiency of Dye-Sensitized Solar Cells by a Multifunctional Composite Photoanode to 14.13 %

We report a new strategy to fabricate a multifunctional composite photoanode containing TiO₂ hollow spheres (TiO₂-HSs), Au nanoparticles (AuNPs) and novel NaYF₄ : Yb,Er@NaLuF₄ : Eu@SiO₂ upconversion nanoparticles (UCNPs). The AuNPs are grown on the photoanode film including TiO₂-HSs and UCNPs by a simple in situ plasmonic treatment. As a result, an impressive power conversion efficiency of 14.13 % is obtained, which is a record for N719 dye-based dye-sensitized solar cells, demonstrating great potential for the solar cells toward commercialization. This obvious enhancement is ascribed to a collaborative mechanism of the TiO₂-HSs exhibiting excellent light-scattering ability, of the UCNPs converting near-infrared photons into visible photons and of the AuNPs presenting outstanding surface plasmon resonance effect. Notably, a steady-state experiment further reveals that the champion cell exhibits 95.33 % retainment in efficiency even after 180 h of measurements, showing good device stability.     

Rough set theory: a novel approach for extraction of robust decision rules based on incremental attributes

Rough set theory is a new data mining approach to manage vagueness. It is capable to discover important facts hidden in the data. Literature indicate the current rough set based approaches can’t guarantee that classification of a decision table is credible and it is not able to generate robust decision rules when new attributes are incrementally added in. In this study, an incremental attribute oriented rule-extraction algorithm is proposed to solve this deficiency commonly observed in the literature related to decision rule induction. The proposed approach considers incremental attributes based on the alternative rule extraction algorithm (AREA), which was presented for discovering preference-based rules according to the reducts with the maximum of strength index (SI), specifically the case that the desired reducts are not necessarily unique since several reducts could include the same value of SI. Using the AREA, an alternative rule can be defined as the rule which holds identical preference to the original decision rule and may be more attractive to a decision-maker than the original one. Through implementing the proposed approach, it can be effectively operating with new attributes to be added in the database/information systems. It is not required to re-compute the updated data set similar to the first step at the initial stage. The proposed algorithm also excludes these repetitive rules during the solution search stage since most of the rule induction approaches generate the repetitive rules. The proposed approach is capable to efficiently and effectively generate the complete, robust and non-repetitive decision rules. The rules derived from the data set provide an indication of how to effectively study this problem in further investigations.     

Properties of poly(vinyl chloride)/wood flour/montmorillonite composites: Effects of coupling agents and layered silicate

Organomodified montmorillonite (OMMT) was prepared using cetylalkyl trimethyl amine bromide. OMMT and wood flour (WF) were surface-modified by silane coupling agent. They were melt-blended with polyvinyl chloride (PVC) and extruded into wood-plastic composite samples using one conical twin screw extruder. The effects of their contents on the composite mechanical properties were investigated. X-ray diffraction, transmission electron microscopy and scanning electron microscopy observed intercalation and dispersion of the OMMT. FTIR and X-ray photoelectron spectroscopy were used to analyze the silane-modification effects. The possible reaction mechanisms were proposed. After wood flour was modified by 1.5 phr silane, the impact strength and the tensile strength of wood flour-PVC composite were increased by 14.8% and 18.5%, respectively. Mechanical tests showed that the addition of OMMT did not enhance the untreated wood flour-PVC composites. However, adding 0.5% OMMT did improve the mechanical properties of the treated ones. The grafting improved the interfacial compatibility between components producing higher properties of the composites. Further addition of OMMT reinforced the composites. Too higher contents of silane and OMMT impaired some properties because of weak interfacial layer and higher concentrated stress. Cone calorimetry showed that the fire flame retardancy and smoke suppression of composites were strongly improved with the addition of OMMT.