Fabrication and study of properties of the PLA/Sr2MgSi2O7:Eu2+, Dy3+ long-persistent luminescence composite thin films

In this paper, Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ (SMS) particles were first synthesized by sol–gel method and then modified with 3-aminopropyltriethoxysilane (APS) to improve their dispersibility and compatibility in the polylactic acid (PLA) matrix. The structure of pure SMS particles was analyzed by XRD and XPS. The properties of SMS particles before and after modification were characterized by FT-IR and SEM. PLA/SMS composite films containing 15 wt% of SMS particles were prepared by spin coating on silicon wafer. Their morphology and luminescence properties were examined. It was found that the composite films can be excited by a broad band from 330 nm to 425 nm with the highest excitation intensity at 360 nm. The fluorescent and phosphorescent emission bands of the composite films and SMS particles all have a major emission peak at 468 nm. Decay curves of the composite films have a similar tendency with that of the pure SMS particles, except for the lower intensity.     

Tunable permittivity in polymer composites filled with Si-based semiconductors by regulating induced polarization

Induced polarization shows a significant influence on dielectric permittivity of 0–3 polymer composites containing Si-based semi-conductive fillers. The nature of induced polarization is the increased electric conductivity or decreased band gap in Si-based semi-conductive fillers. In this work, the dependence of induced polarization onto particle size of α-SiC filler together with polarity of polymer matrix and Si-based semi-conductive filler has been elaborately investigated by detecting the permittivity of composites. It was found that increasing the grain size of SiC filler, improving the polarity of polymer matrix and reducing the band-gap of Si-based semi-conductive filler could favor the enhancement of the overall induced polarity in the composites. As a result, the significantly improved dielectric permittivity of composites higher than both of the neat polymer and filler was observed depending on the constituents of the composites. The highest dielectric permittivity of ~215@1 kHz was achieved in poly(vinyl alcohol) based composite filled with 60 vol% of 12 µm SiC particles. The dielectric permittivity of these 0–3 composites could be well tuned in a wide range through altering their constituents. This work might open a facile route to obtain the promising high-performance dielectric composite materials by regulating the degree of induced polarization.     

Low-power compact composite field AES S-Box/Inv S-Box design in 65 nm CMOS using Novel XOR Gate

The Substitution box (S-Box) forms the core building block of any hardware implementation of the Advanced Encryption Standard (AES) algorithm as it is a non-linear structure requiring multiplicative inversion. This paper presents a full custom CMOS design of S-Box/Inversion S-Box (Inv S-Box) with low power GF (2⁸) Galois Field inversions based on polynomial basis, using composite field arithmetic. The S-Box/Inv S-Box utilizes a novel low power 2-input XOR gate with only six devices to achieve a compact module implemented in 65 nm IBM CMOS technology. The area of the core circuit is only about 288 μm² as a result of this transistor level optimization. The hardware cost of the S-Box/Inv S-Box is about 158 logic gates equivalent to 948 transistors with a critical path propagation delay of 7.322 ns enabling a throughput of 130 Mega-SubBytes per second. This design indicates a power dissipation of only around 0.09 μW using a 0.8 V supply voltage, and, is suitable for applications such as RFID tags and smart cards which require low power consumption with a small silicon die. The proposed implementation compares favorably with other existing S-Box designs.     

兴山县有线数字电视系统技术方案的实施

主要介绍制定兴山县有线数字电视系统设计方案的依据、系统的功能、频道规划、系统配置、技术指标、设备选型、工程概算、质量保证措施等方面的经验。     

铝基刚挠结合板制作工艺探讨

金属铝基由于其良好的散热性能,广泛应用于LED方面;但随着PCB技术进一步向短、小、轻、薄的方向发展,其平面安装技术在安装空间方面受到了极大的限制,因此,如何实现金属基板三维折叠安装成为业界新的研究课题。对铝基＋软硬结合板的制作工艺进行了可行性探讨,通过铝基表面复合处理工艺＋纯胶预贴局部撕胶十二氧化碳激光切割技术有效实现了金属铝基与挠性电路的有机结合,满足了客户对金属基板实现三维安装的特种需求。     

Self-diffraction in Porous Silicon/PMMA-DR1 Composite Films

Two-layer structure consisting of PS/PMMA-DR1 composite film planar waveguide layer on porous silicon cladding layer was fabricated in our experiment. The induced grating based on the third nonlinear optical properties was formed by interaction of two Nd ： YAG laser beams at 1 064 nm in the porous silicon/PMMA-DR1 waveguide. The diffraction efficiency of the first order diffracted light is measured to be about 0.2% of the total output.     

复合CrCO-Ti保护薄膜的热稳定性研究

用非平衡脉冲直流磁控溅射技术制备出了复合CrCO-Ti和CrCO保护薄膜,在氮气气氛条件下,研究了这些薄膜的结构、粘合力、耐磨性等随退火温度的变化规律和掺Ti对其性能的影响.得出结论:沉积的薄膜是非晶态薄膜,这些薄膜的耐磨能力达到10-8mm3/Nm;掺Ti能增强薄膜的柔韧性和负载能力,但在400℃及以上退火条件下,薄膜的结构、粘合力、耐磨能力等开始变化,而OEM为40%的复合CrCO-Ti薄膜具有较好的热稳定性.     

一种复合燃烧剂的设计研究

采用“燃烧序列”原理设计了一种复合燃烧剂，研究其静态和动态条件下点燃特性及其燃烧性能。试验结果表明，该复合燃烧剂点燃性能好，燃烧温度可达3298℃，持续燃烧13～14min，能够形成较好的高温纵火效果，可作为高效燃烧弹装药使用。     

变质量力学系统Nidsen方程的形式不变性

力学系统对称性与守恒量的研究在数学、力学、物理学中都具有非常重要的意义。力学系统的对称性与守恒量的近代理论主要有Noether对称性理论和Lie对称性理论。形式不变性是不同于Noether对称性和Lie对称性的一种新的对称性理论。本文研究变质量力学系统Nielsen方程的形式不变性，给出变质量保守力学系统Nielsen方程的形式不变性的定义和判据，研究形式不变性和Noether对称性的关系，并举例说明结果的应用。     

An Epoxy Photoresist Modified by Luminescent Nanocrystals for the Fabrication of 3D High‐Aspect‐Ratio Microstructures

An epoxy‐based negative‐tone photoresist, which is known as a suitable material for high‐aspect‐ratio surface micromachining, is functionalized with red‐light‐emitting CdSe@ZnS nanocrystals (NCs). The proper selection of a common solvent for the NCs and the resist is found to be critical for the efficient incorporation of the NCs in the epoxy matrix. The NC‐modified resist can be patterned by standard UV lithography down to micrometer‐scale resolution, and high‐aspect‐ratio structures have been successfully fabricated on a 100 mm scaled wafer. The “as‐fabricated”, 3D, epoxy‐based surface microstructures show the characteristic luminescent properties of the embedded NCs, as verified by fluorescence microscopy. This issue demonstrates that the NC emission properties can be conveniently conveyed into the polymer matrix without deteriorating the lithographic performance of the latter. The dimensions, the resolution, and the surface morphology of the NC‐modified‐epoxy microstructures exhibit only minor deviations with respect to that of the unmodified reference material, as examined by means of microscopic and metrologic investigations. The proposed approach of the incorporation of emitting and non‐bleachable NCs into a photoresist opens novel routes for surface patterning of integrated microsystems with inherent photonic functionality at the micro‐ and nanometer‐scale for light sensing and emitting applications.