基于聚合反应制备的钛离子掺杂LiFePO4/C复合材料

首先基于聚合反应合成FePO4/PANI前驱体,再以为LiOH·H2O,FePO4/PANI 和 PVA原料制备了LiFePO4正极材料,此外再对其进行碳包覆以及Ti4+掺杂,三种试样分别标记为LiFePO4,LiFePO4/C及LiFe0.96Ti0.02PO4/C.通过XRD、EDS及充放电测试等手段表征了材料的微观结构与电化学性能.实验结果证明:试样的XRD图谱均与标准LiFePO4图谱一致,不存在无定形碳衍射峰.与未掺杂试样LiFePO4/C相比,LiFe0.96Ti0.02PO4/C的电子电导率与其相近,但离子扩散系数有所改善,Ti4+在晶格中均匀分布,因此与其他两试样相比,其电化学性能更好.试样在C/10、C/2、1C、3C及5C倍率下的放电比容量为158.7 mAh·g-1、153.3 mAh·g-1、147.6 mAh·g-1、136.4 mAh·g-1及123.5 mAh·g-1,具有良好的倍率性能与电位稳定性.     

SiO2纳米线/纳米颗粒复合结构的制备及光致发光性能研究

采用热蒸发法制备了非晶SiO2纳米线/纳米颗粒复合结构,确定了非晶SiO2纳米线、微米颗粒及SiO2纳米线/纳米颗粒复合结构生长的工艺条件,并利用XRD、SEM、Raman、PL光谱等技术手段分析表征样品.实验结果表明,在不同的沉积温度范围内,生长样品的形貌和结构不同;SiO2纳米线/纳米颗粒复合结构的发光区与Si衬底明显不同,主要集中在黄绿光范围.     

Science and technology of stressed liquid crystals: display and non-display applications

ABSTRACT

Stressed liquid crystals (SLCs) have emerged as promising tunable electro-optical materials more than a decade ago. They are optically transparent and are characterized by a giant phase modulation of the incident light (Nπ, N >> 1), fast (millisecond and shorter) electro-optical response, and a relatively low driving voltage (～1 V/μm). Surprisingly, despite their advanced electro-optical performance, these new materials did not receive due attention in the research community. One possible reason of such an inadequate interest in SLCs is the lack of the well-documented procedure describing how to actually produce these materials. This paper is aimed at the development of such a step-by-step practical guide suitable for experimentalist and engineers. The proposed technology is applied to produce and characterize SLCs. In addition, some applications of the materials are briefly discussed and a broader overview of their possible use is outlined.     

Electrical and structural properties enhancement in plasticized high Tg polymers using metal salts

Plasticized polymer electrolyte composite has been prepared in the form of a film by solution casting method. Poly (ethyl methacrylate) (PEMA) acts as a host polymer and is doped with Sodium Iodide (NaI). Ethylene carbonate (EC) added as a plasticizer and also enhances amorphicity of the polymer electrolyte. The electrical conductivity of the PEMA+NaI was evaluated using complex impedance spectroscopy. Maximum ionic conductivity obtained at room temperature was 8.75 × 10^?6 S/cm with the composition of PEMA: NaI (30%) + 60% EC. The conductivity further increased with increase in temperature and moved up to 5.8 × 10^?5 S/cm. Scanning electron microscopy was used to study the surface morphology of the composite film. Fourier transform infrared ray and X-ray diffraction data confirmed the complexation of material.     

Application of robust color composite fringe in flip-chip solder bump 3-D measurement

This study developed a 3-D measurement system based on flip-chip solder bump, used fringes with different modulation intensities in color channels, in order to produce color composite fringe with robustness, and proposed a multi-channel composite phase unwrapping algorithm, which uses fringe modulation weights of different channels to recombine the phase information for better measurement accuracy and stability. The experimental results showed that the average measurement accuracy is 0.43μm and the standard deviation is 1.38 µm. The results thus proved that the proposed 3-D measurement system is effective in measuring a plane with a height of 50 μm. In the flip-chip solder bump measuring experiment, different fringe modulation configurations were tested to overcome the problem of reflective coefficient between the flip-chip base board and the solder bump. The proposed system has a good measurement results and robust stability in the solder bump measurement, and can be used for the measurement of 3-D information for micron flip-chip solder bump application.     

以新型空壳颗粒复合材料为分配层的成层防护结构抗爆性能试验研究

以成层式人防工程为试验研究背景,分别采用黄沙和新型空壳颗粒复合材料做分配层,开展大比尺集团装药化爆模拟试验,考察其衰减爆炸冲击波的能力。试验结果表明,采用颗粒复合材料构建的分配层,在相同装药量下,遮弹层的变形和破坏明显大于黄沙分配层,应力波上升沿加大,波形脉宽增加,平均峰值应力大概是黄沙分配层的0.65左右,除装药正下方的个别颗粒遭受粉碎性破坏外,绝大部分空壳颗粒依然完好,只是表层泡沫陶瓷略有破损。这说明新型空壳颗粒复合材料不但对爆炸波有非常明显的衰减弥散作用,而且具备承受多次打击的能力。用这种材料做分配层,可大幅提高地下人防工程的抗爆能力。     

锂硫电池用多孔碳/硫复合正极材料的研究

锂硫电池具有高的理论比容量和理论能量密度,被认为是当前最有前景的二次电池体系之一。现阶段锂硫电池的研究工作主要集中于高性能硫正极材料的设计与合成。具有优良的导电性、良好的结构稳定性和多孔结构的纳米碳材料,比如活性碳、介孔碳、超小微孔碳、多级结构多孔碳、空心碳球和空心碳纤维,充分满足了锂硫电池正极材料对碳基体的要求。本文综述了近年来多孔碳/硫复合材料作为硫正极的研究进展。总结了以具有不同结构特征的多孔碳基体负载硫组装的锂硫电池的电化学性能,并分析了不同多孔结构对性能的影响。最后在此基础上,从多孔碳/硫复合正极材料的设计和合成的角度,展望了其未来的发展趋势。     

天然高分子复合羟基磷灰石材料的制备与应用

羟基磷灰石(HA)是人类与动物骨骼中主要无机物组成成分,因其具有良好的生物相容性、生物活性和骨传导作用,作为新型合成生物材料已应用于骨组织的修复与替代技术。本文在介绍HA主要制备方法(如:沉淀法、乳液法、水热反应法、溶胶-凝胶法、机械化学法、固态合成法、水解法、超声化学法、热解法、模板法和电沉积法等)和应用的基础上,重点综述了各类天然高分子与HA复合材料的制备及应用研究进展。天然高分子,如:纤维素、淀粉、甲壳素、壳聚糖、蛋白(包括胶原蛋白、明胶、角蛋白、丝蛋白和植物蛋白)等,与HA复合后制备的天然高分子复合羟基磷灰石材料,在保持其生物相容性的同时,又能改善复合材料的机械性能与生物活性,使其可用于医用材料、载体材料和吸附分离材料。最后,本文指出为了满足生物体内的特殊环境(如强的韧性、与骨生长速度匹配性能等)及不同领域的要求,天然高分子复合HA材料需要发展的方向。     

亚稳态分子间复合物反应机理研究

亚稳态分子间复合物（metastable intermolecular composite,MIC）由于具有超高反应燃烧速率及能量释放速率、高体积能量密度、低扩散距离和绿色环保等优点,在微型含能器件、火箭推进剂和绿色火工药剂等军用领域展现了很好的应用潜力。其反应机制与传统的含能材料不同,且具有超高速反应的瞬时性及复杂性,对其反应机理仍然缺乏清晰的认识,这限制了其应用研究的进展。本文对近年来亚稳态分子间复合物的反应机理研究进行综述,重点讨论具有代表性的“金属-氧翻转机理”和“预点火-熔结机理”。对于MIC材料的反应机理研究,本文主要从实验研究、理论模型研究和数值模拟研究三个方面进行分析。改性MIC材料是对材料性能进行调控的重要手段,是目前及未来的重要发展趋势之一,在论文最后对其反应机理做了重点叙述。通过对当前研究现状的归纳与分析,给出了当前的重要研究成果以及研究中出现的问题,并对未来的研究发展趋势进行了展望。     

Ferrofluids Containing Fe3O4 Nanoparticles in Solidified Photoresist Carrier

Ferrofluids, formed by magnetic nanoparticles uniformly dispersed in a liquid carrier, respond to an external magnetic field, which enable the fluid's position by applying a magnetic field. Here, ferrofluids composed of Fe₃O₄ nanoparticles with oleic acid and oleylamine as the surfactant and photoresist, respectively, were prepared. Under an external magnetic field, the movement and the position of ferrofluids and the injection of the fluids into complex shapes were easily achieved. The ferrofluid surfaces were distorted under the magnetic field, and the surface structue was controlled by the applied field strength. Using a photoresist as the liquid carrier, it was possible to solidify the ferrofluids by UV irradiation. The shape and the position of the solid superparamagnetic nanoparticles/polymer composites were also determined by the external magnetic field.