一种执行机构等效装置设计

为了满足航天器桌面散态匹配试验测试需求,研制一种基于PC104总线的执行机构等效装置,详细阐述了等效装置的功能、工作原理、硬件电路设计、软件设计思想,该系统采用模块化、可配置软件架构设计,实现了正常、应急多测试工况一体化设计;应用严格的窗口比较器硬件电路设计技术,实现信号电压幅值的高精度采集,确保输入信号的可靠判定;利用FPGA技术突破信号脉宽高精度采集和信号延时高精度可控等关键技术,该系统实现了输入信号幅值、脉宽的实时采集、存储与显示,并按照事先设定的工作模式及配置参数,完成不同测试工况下输出信号的模拟反馈。试验结果表明,系统稳定可靠,人机界面友好,满足航天器多测试工况控制时序和功能检查需求。     

Independent components analysis coupled with 3D-front-face fluorescence spectroscopy to study the interaction between plastic food packaging and olive oil

Olive oil is one of the most valued sources of fats in the Mediterranean diet. Its storage was generally done using glass or metallic packaging materials. Nowadays, plastic packaging has gained worldwide spread for the storage of olive oil. However, plastics are not inert and interaction phenomena may occur between packaging materials and olive oil. In this study, extra virgin olive oil samples were submitted to accelerated interaction conditions, in contact with polypropylene (PP) and polylactide (PLA) plastic packaging materials. 3D-front-face fluorescence spectroscopy, being a simple, fast and non destructive analytical technique, was used to study this interaction. Independent components analysis (ICA) was used to analyze raw 3D-front-face fluorescence spectra of olive oil. ICA was able to highlight a probable effect of a migration of substances with antioxidant activity. The signals extracted by ICA corresponded to natural olive oil fluorophores (tocopherols and polyphenols) as well as newly formed ones which were tentatively identified as fluorescent oxidation products. Based on the extracted fluorescent signals, olive oil in contact with plastics had slower aging rates in comparison with reference oils. Peroxide and free acidity values validated the results obtained by ICA, related to olive oil oxidation rates. Sorbed olive oil in plastic was also quantified given that this sorption could induce a swelling of the polymer thus promoting migration.     

Determining nanomaterials in food

Nanotechnology has emerged as one of the most innovative technologies and has the potential to improve food quality and safety. However, there are a few studies demonstrating that nanomaterials (NMs) are not inherently benign.This review highlights some current applications of NMs in food, food additives and food-contact materials, and reviews analytical approaches suitable to address food-safety issues related to nanotechnology.We start with a preliminary discussion on the current regulatory situation with respect to nanotechnology in relation to foods. We cover sample preparation, imaging techniques (e.g., electron microscopy, scanning electron microscopy and X-ray microscopy), separation methods (e.g., field-flow fractionation and chromatographic techniques) and detection or characterization techniques (e.g., light scattering, Raman spectroscopy and mass spectrometry). We also show the first applications of the analysis of NMs in food matrices.     

顶空/气相色谱-质谱法分析方便面印刷包装材料中挥发性有机物

利用顶空/气相色谱-质谱(HS/GC-MS)联用法对袋装方便面印刷包装材料中7种挥发性有机物(异丙醇、乙酸乙酯、苯、乙酸丁酯、乙苯、间/对二甲苯、邻二甲苯)进行了检测分析.优化的实验参数为:平衡温度80℃,平衡时间40 min.本方法线性关系良好,7种挥发性有机物的相关系数均大于0.9991,检出限为0.004～0.0...     

甲壳素基新材料研究进展

甲壳素/壳聚糖良好的生物相容性、生物可降解性及独特的生理活性使其成为非常有应用价值的天然高分子材料,当前已成为新材料领域的研究热点.甲壳素/壳聚糖具有良好的可加工性能,可固定贵金属、半导体纳米材料等活性催化物质,同时其本身也具有催化作用,是一类绿色环境友好的高分子催化材料.良好的生物相容性和生物可降解性使甲壳素/壳聚糖...     

Flash memory effects based on styrene/maleimiade copolymers with pendant azobenzene chromophores

Two styrene/maleimiade copolymers with pendant azobenzene chromophores, poly(styrene-1-(4-phenylazo-phenyl)-pyrrole-2,5-dione) (PS-DP) and poly((4-vinyl-benzyl)-9H-carbazole-1-(4-phenylazo-phenyl)-pyrrole-2,5-dione) (PVCz-DP), were synthesized. The polymeric memory devices based on each of the two polymer films (ITO/Polymer/Al) show similar rewritable flash memory behaviors but different transition voltages. By introduction of carbazole groups in the polymer side chains, the voltage difference from OFF to ON state of ITO/PVCz-DP/Al is reduced obviously in comparison with that of ITO/PS-DP/Al, which is beneficial to the protection of devices. Both ITO/PS-DP/Al and ITO/PVCz-DP/Al show high stability under a constant stress or continuous read pulses voltage of 1.0 V. The memory mechanism is governed by space-charge limited conduction (SCLC) on the basis of the I–V curves of these fabricated memory devices. With excellent flash memory characteristics and simple processability, the memory devices fabricated with these two styrene/maleimiade copolymers have potential applications for the future electronic memory devices.     

Simulation of Optical Devices Using Parallel FDTD Method

On this paper, we investigate the algorithm and efficiency of simulation of optical devices using parallel computing method, implement some real wavelength division multiplexing (WDM) components such as resonators to test the method's possibility and efficiency.     

Coupling Fibers to Planar Waveguides Using a High-Temperature Epoxy

Computer simulation was used to understand the adhesive-based coupling of optical fibers to planar waveguides with a view to adhesive development. Satisfactory coupling performance could be achieved with facet-angled fibers and waveguides, regardless of the adhesive's index and optical loss. A high-temperature epoxy adhesive was developed for coupling applications based on the simulation. The adhesive is able to achieve a material-related loss of -0.05 dB and a back-reflection loss of less than -50 dB in the coupling. In addition, the adhesive has excellent mechanical and thermal properties and can easily meet the Telcordia standard GR1221 while withstanding high temperatures and high optical power.     

Automatic optic waveguide chip packaging system based on center-integration algorithm

In order to realize efficient automatic packaging of the waveguide chip and reduce its cost, an integrated optic waveguide chip packaging system based on center-integration algorithms is designed and fabricated, which realizes 11-dimension position adjustment and fewer operation times. The integration center position is obtained through the sampling data. The system can avoid local optimum and reduce packaging time as well as packaging loss. The automated alignment of a single-core fiber with channel waveguide and single-core fiber system is completed in less than 2 min. The packaging experiment of a single-core fiber array with 1 × 8 splitter coupler and 8-core fiber array is completed in less than 5 min with an insert-loss of less than 10.5 dB and homogenization of less than 0.4 dB. The system is validated with good efficiency and practicability.     

Recent advancements of moiré and microscopic moiré interferometry for thermal deformation analyses of microelectronics devices

Moiré and microscopic moiré interferometry are reviewed as they are applied to thermal deformation analyses of microelectronics devices. Applications to diverse problems are illustrated to demonstrate wide applicability of the methods. The whole-field displacement information, with various sensitivity and resolution scales, is ideally suited for the deformation study of a broad range of problems in deformation analyses of microelectronics devices.