Effective holographic recordings in the photopolymer nanocomposites with functionalized silica nanoparticle and polyurethane matrix

Effective holographic nanocomposites were developed by the surface-functionalized silica nanoparticles and two acrylate monomers/polyurethane (PU) matrix polymer. The functionalization was done with silane compounds carrying long alkyl chain or vinyl group. We evaluated the holographic nanocomposite films by the diffraction efficiency, volume shrinkage, optical loss, and the film morphology. It was found that acrylate monomers/PU system gave higher diffraction efficiency than those of two monomers due to the high refractive index mismatch between the acrylate-rich and PU-rich regions. With the modification of silica particle, up to 35% of particle loading was possible to give a maximum diffraction efficiency of 93.6% for a film of 20 μm in thickness, along with improved refractive index modulation and the sensitivity.     

Improving the performance of methylene blue sensitized photopolymer by doping with nickel ion

Holographic performance of an economically cheap metal ion doped photopolymer material is presented. We investigated the effect of incorporation of nickel ion into the methylene blue sensitized poly (vinyl alcohol)/acrylamide (MBPVA/AA) photopolymer system. The composition and preliminary characterization of the developed photopolymer material is reported. The presence of nickel ion improves the diffraction efficiency, stability of the material and it operates in a wide range of spatial frequencies (550–2000 lines/mm) at exposure energy of 100 mJ/cm². When nickel ion concentration was 0.01 mM, maximum diffraction efficiency of 84% at exposure energy of 100 mJ/cm² with spatial frequency 1335 lines/mm could be achieved for gratings recorded using wavelength of 632.8 nm. The material showed panchromaticity with more than 70% diffraction efficiency in both blue and green regions. Effects of humidity and temperature on the stored gratings were studied by keeping films in different environmental conditions. Suitability of recording large area holograms was also explored.     

对绿光敏感的全息存储光致聚合物性能的研究

报道了一种对绿光敏感的以丙烯酰胺为单体的光致聚合物，该光聚物由单体、光引发剂、共引发剂和成膜物组成。可以得到材料的最大衍射效率为55％。将光聚物用不同温度进行烘烤加热，可以看到材料的折射率调制度会增加。使用角度复用技术在光聚物中存储10幅全息图，说明所研究材料有希望于大容量体全息存储。     

双固化型全息用光致聚合物的研制及其全息性质研究

以环氧树脂为成膜树脂，甲基丙烯酸甲酯为光聚合活性单体，研制了一种双固化型全息用光致聚合物材料。通过成膜树脂配方的选取和光敏染料的选取优化了样片的配方组成，用457nm的蓝光在样片中记录全息光栅，用632．8nm的红光作为探针光，研究了样片的衍射效率、灵敏度、折射率调制度、预曝光量和收缩率等全息性能，测试结果表明单体的含量与组分的选取是影响样片衍射效率的主要因素，同时样片的制膜工艺对其全息性能也有很大的影响，通过配方的调整和制膜工艺的优化，部分样片的综合性能已基本达到实用化的需要。     

Co-doping with polysquaraine enhances the holographic optical data storage of PMMA/PQ photopolymers

In this study, we synthesised poly(3-octylpyrrole-co-squaric acid) (PSQ3), a polysquaraine, through the reaction of 3-octylpyrrole and squaric acid, and then co-doped it with phenanthrenequinone (PQ) into poly(methyl methacrylate) (PMMA) to improve the holographic data storage characteristics of the photopolymer. The photopolymers co-doped with relatively small amounts of PSQ3 exhibited greatly improved holographic recording characteristics, including superior diffraction efficiency and dynamic range (M#). Among the samples co-doped with PQ and PSQ3, the maximum diffraction efficiency reached 54.8% (cf. 9.0% for PMMA/PQ) without further downgrade and the value of M# reached 1.05 (cf. 0.46 for PMMA/PQ). Therefore, the holographic data storage characteristics of the photopolymer PMMA/PQ were improved through co-doping with PSQ3.     

High refractive index nanocomposite cover-layer for optical storage media

A nanocomposite cover-layer consisting of a UV curable resin and TiO₂ nanoparticles, a dielectric cover-layer, and a hybrid cover-layer for near-field optical recording media are prepared and characterized. The dielectric and the nanocomposite cover-layers with a refractive index of about 1.95 showed a rough surface, which yields collisions between a solid immersion lens and a cover-layer during the near-field gap servo test. A smooth surface with a nanocomposite cover-layer can be obtained by reducing the refractive index to less than 1.86, which results in a successful gap servo without the collision.     

一种数据网格存储模型与并行下载调度算法

针对在数据网格中创建多副本虽可有效提升下载速度、降低网络流量,但多副本创建会带来大量存储开销和网络流量开销,以及基于GridFTP协议的各种并行下载算法虽可进一步提升下载速度,但仍不能解决多副本对存储空间和网络流量的影响的问题,提出了一个能保证数据的完整性、存储的可靠性和降低存储空间的数据网格存储模型,并基于该存储模型和GridFTP协议,提出了一个并行下载调度算法。实验表明,该算法只需要较少的冗余便可达到现有的针对全副本的并行下载算法可达到的理想下载速度,取得较好的效果,实现并行快速传输、节约存储空间和降低网络流量的目标。     

双光子多层荧光存储中的变焦选层技术

为了在双光子多层荧光数据存储中实现对信息层的跟踪聚焦,基于目前的光盘存储系统和双元透镜控制方案,提出了一种变焦选层技术。两个可独立控制的音圈电机负责调节两物镜的相对位置。利用聚焦模块提取出的聚焦误差信号,读写系统控制两个电机协调动作改变焦点位置,使得读写焦点在对选定层读写过程中跟踪盘片抖动。选层操作可通过控制一个音圈电机完成。因此,读写系统能实现简单盘片结构条件下的多层荧光数据存储,同时聚焦模块可使系统与现有CD/DVD盘片兼容。利用二维精密平移台和三洋光头(SF-HD60S)中的音圈电机和物镜进行了双光子三维信息读写实验,在材料中存储了三层数据,点间距4μm,层间距20μm。     

面向海量NetFlow数据的存储和查询处理方法研究

针对全国骨干网高速海量Net Flow数据到来速度快、数据量大以及对所存数据进行频繁多维查询操作的特点,提出了一种多维属性聚簇存储(MACS)模型。该模型根据实际应用环境中查询的特点对数据进行空间分片,以并行加流水的方式对数据进行存储。此外,为Net Flow提出了一种超多面体的查询模式。真实环境实验结果表明,运用MACS模型实现的系统单点数据实时存储速度达到270万条/s,远远快于其他的数据分析系统,并且多维属性查询的速度优于Hive和Impala。