环氧稀释剂(1,2,8,9-双环氧-4-乙烯基环己烯)合成方法研究进展

本文介绍了用有机过氧酸、次卤酸及其衍生物和过硫酸盐三种氧化剂合成4-乙烯基环己烯双环氧化合物的方法,并对几种方法进行了机理分析和比较,结果表明:采用过硫酸盐氧化法得到的收率最高(78%),而且方法简便,成本低廉。     

Microstructure and properties of novel ReO<Subscript>2</Subscript> /polyimide nanocomposite films

A series of Rhenium (VII, Re⁷⁺) compound-doped polyimide (PI) nanohybrid films had been successfully fabricated from methyltrioxorhenium (MTO) and polyamic acid (PAA) via the solution direct-dispersing method, followed by a stepwise thermal imidization process. X-ray photoelectron spectroscopy (XPS) confirmed that MTO had decomposed into Re (IV) oxidation state (ReO₂). Field emission scanning electron microscopy (FE-SEM) showed that for the differrent hybrid films, the ReO₂ nanoparticles which formed by MTO decomposing well dispersed in polyimide matrix with a size of 40–60 nm. Thermal analysis indicated that the introduction of MTO decreased the thermal stability and the glass transition temperature (T_g) because of the unstable MTO. DMTA and static tensile measurements showed that the storage modulus and the elongation at break of nanocomposite films had a maximum value when the 1% of MTO was doped in PI, while the tensile strength decreased with increasing MTO content on the whole.     

Influence of H4SiW12O40 loading on hydrocracking activity of non-sulfide Ni-H4SiW12O40/SiO2 catalysts

The effect of H₄SiW₁₂O₄₀ loading on the catalytic performance of the reduced Ni-H₄SiW₁₂O₄₀/SiO₂ catalysts for hydrocracking of n-decane with or without the presence of thiophene and pyridine is studied. The catalysts were characterized by BET, XRD, Raman, XPS, H₂-TPR, H₂-TPD, NH₃-TPD and FT-IR of pyridine adsorption. It was found that addition of H₄SiW₁₂O₄₀ to the system increases the catalytic activity and the promoting effect is a function of the H₄SiW₁₂O₄₀ loading. The best result was obtained on 5%Ni-50%H₄SiW₁₂O₄₀/SiO₂ catalyst which shows the highest activity for hydrocracking of n-decane and excellent tolerance to the sulfur and nitrogen compounds in the feedstock. The results showed that a suitable amount of H₄SiW₁₂O₄₀ loading on the 5%Ni/SiO₂ catalyst increases the amount of both hydrogen adsorbed and Brønsted acid and Lewis acid sites on the catalyst. The high catalytic performance of the catalyst can be related to the nature of H₄SiW₁₂O₄₀ and the proper balance between metal and acid functions.     

Influence of surfactants on rheological behaviors of polyacrylonitrile/dimethyl sulfoxide/silicon blending polymer solutions

KH550, KH560, CTAB, and F127 were adopted to modify silicon (Si) to improve the dispersity and stability of Si in the polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO) polymer solutions. The influence of surfactants on rheological behaviors of PAN/DMSO/Si blending polymer solutions was investigated by an advanced solution and melt rotation rheometer. The homogeneity and stability were also studied. The results showed that the surfactants could change the viscosity dependence of blending polymer solutions on shear rate, temperature and storage time by increase the steric hindrance of Si. Among the four solutions, PAN/DMSO/Si blending polymer solution with F127 exhibited the lowest viscosity, activation energy and the smallest structural viscosity index and exhibited the trend close to the Newtonian fluids. Moreover, PAN/DMSO/Si blending polymer solution with F127 exhibited the best dispersity and stability, indicating its best physical properties and machinability.     

分子动力学方法的模拟参数对结果的影响

主要研究了利用分子动力学方法(MD)模拟等离子体与材料表面相互作用过程时分子动力学方法的参数对模拟结果的影响.详细分析了Berendsen热浴的应用时间、耦合强度和模拟时间量(单个轨迹的作用时间、弛豫时间)对模拟结果的影响,结果表明,热浴的应用时间对模拟结果的影响很大,而其它参数对模拟结果没有太大的影响.     

上海世博会中国馆国家馆结构设计与研究

2010年上海世博会中国馆的国家馆造型独特,其底部架空,展区部分层叠出挑,呈四棱台斗冠状。屋面由混凝土筒体出挑34.75m,不但使得竖向质量分布不均匀,还使得楼盖的转动惯量大,导致结构的扭转周期成为第一周期。介绍了国家馆的结构体系、结构布置、结构分析以及主要的构造加强措施。利用楼、电梯间设置四个落地的混凝土筒体作为承重和抗侧力结构,利用建筑的倒梯形造型设置斜柱来支承楼盖大跨度钢梁,在确保结构安全的前提下,最大限度地满足了建筑使用功能的要求。分析了扭转周期为第一自振周期对结构的影响以及底部挑空对结构竖向侧向刚度分布的影响。详细的计算分析及模拟振动台试验结果表明,虽然扭转周期为第一周期,但结构的扭转反应并不严重,对结构的抗震性能影响不大,结构具有良好的抗震性能,可达到预定的抗震性能目标。     

神经网络集成融合模型研究及应用

针对专家系统等单一模型解决发动机故障诊断存在的算法复杂度高、诊断准确率低等问题，提出了BP神经网络集成与DS证据推理相融合的神经集成融合模型，不仅实现了发动机不同部位的专家经验与实际观测数据的特征级融合，还实现了多个模型的优势互补。通过对该方法和传统的专家系统方法比较得出，神经网络集成融合方法提高了7.1%的诊断准确率。     

A novel method to prepare mineralized fibroin fiber

In this paper, a novel method was developed to prepare mineralized fibroin fiber. We used fibroin gel to control the biomineralization of calcium phosphate and obtained one kind of mineralized fibroin fiber with the length of 1–2 mm. It has the potential to be used to enhance the strength of tissue engineering scaffold. Scanning electron microscopy (SEM) results showed that hydroxyapatite (HA) was mainly deposited on the surface of mineralized fiber. Fourier transform infrared spectroscopy (FTIR) results displayed the red shifts of absorption bands of amide II and amide III (9 and 5 cm⁻¹, respectively), which were related to the strong chemical interaction between HA and fibroin. It was also found that HA was at low content (12.5%) and the ability of gelled fibroin to induce mineralization decreased greatly because of the formation of β-structures in gelled fibroin molecules, which showed the importance of molecular structure in the regulation of the biomineralization process.     

气-固反应法合成准-维纳米结构材料的研究

综述了利用气-固反应法合成准-维纳米结构材料的研究进展，简要介绍了气-固反应法与气相法的不同点，重点讨论了用气-固反应法直接热氧化或硫化铜、铁、锌等金属以合成准-维纳米结构氧化物、硫化物的过程以及气-固反应法的生长机理，并介绍了准-维纳米结构材料的潜在应用。     

输变电设备检修计划决策技术评述

电网和技术的发展给输变电设备检修计划决策带来了新的机遇和挑战。分析了输变电设备检修计划决策关联技术,提出了新形势下检修计划决策研究及应用技术面临的主要问题和挑战,对输变电设备风险评估、计划方式下电网安全校核及风险评估、检修计划协调优化算法、系统研发等关联技术的发展现状进行了评述,并从输变电设备风险评估、检修计划优化决策、研发自动化系统方面提出了建议和技术展望。