材料基因工程技术在分子筛领域中的应用

材料基因工程是近年来材料领域兴起的前沿技术, 其基本理念是融合材料高通量计算、 高通量实验和数据技术加速新材料的设计和研发. 分子筛作为一种重要的化工材料, 因其良好的热稳定性、 较高的比表面积、 独特的孔道结构及可调变的元素组成和酸性, 在气体吸附、 分离、 异相催化和离子交换等工业领域应用广泛. 近年来, 融合高通量计算、 高通量实验和数据库技术的材料基因工程技术正逐步应用于分子筛研发等领域: 高通量计算能够从理论上预测并筛选出具有优异性能的分子筛合成目标、 高通量实验显著提升了分子筛材料合成与表征的效率、 数据库技术则为未来挖掘分子筛材料的合成规律与构效关系奠定了数据基础. 本文主要从这3个方面阐述材料基因工程技术在分子筛材料研发领域的应用及进展, 总结以功能为导向、 定向设计和构筑分子筛材料所面临的机遇与挑战, 并对材料基因工程技术在分子筛领域的前景进行了展望.     

铁氨基黏土-葡萄糖氧化酶纳米复合催化剂的构筑及多酶级联反应研究

以铁氨基黏土(FeAC)为载体, 通过共价交联固定葡萄糖氧化酶(GO_x), 构筑了铁氨基黏土-葡萄糖氧化酶纳米复合催化剂(FeAC-GO_x). 利用FeAC的过氧化物酶活性, 与GO_x结合进行级联反应, 可催化葡萄糖转化为过氧化氢并产生显色反应; 采用扫描电子显微镜(SEM)、 X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对FeAC-GO_x进行了形貌和结构表征, 并评价了其酶动力学参数、 催化稳定性和重复使用性等. 结果表明, GO_x的固定化率可达到76.4%, 所构筑的纳米结构酶复合体系具有高效的级联催化能力. 与天然酶体系相比, FeAC-GO_x具有更优异的温度和pH耐受性, 且在重复使用6次后, 酶催化活性无明显降低. 该体系不仅为新型葡萄糖传感器的开发奠定了基础, 还为多酶级联纳米结构酶的构筑提供了新思路.     

Assembly of tobacco mosaic virus into fibrous and macroscopic bundled arrays mediated by surface aniline polymerization

One-dimensional (1D) polyaniline/tobacco mosaic virus (TMV) composite nanofibers and macroscopic bundles of such fibers were generated via a self-assembly process of TMV assisted by in-situ polymerization of polyaniline on the surface of TMV. At near-neutral reaction pH, branched polyaniline formed on the surface of TMV preventing lateral association. Therefore, long 1D nanofibers were observed with high aspect ratios and excellent processibility. At a lower pH, transmission electron microscopy (TEM) analysis revealed that initially long nanofibers were formed which resulted in bundled structures upon long-time reaction, presumably mediated by the hydrophobic interaction because of the polyaniline on the surface of TMV. In-situ time-resolved small-angle X-ray scattering study of TMV at different reaction conditions supported this mechanism. This novel strategy to assemble TMV into 1D and 3D supramolecular composites could be utilized in the fabrication of advanced materials for potential applications including electronics, optics, sensing, and biomedical engineering.     

Silica hollow nanospheres as new nanoscaffold materials to enhance hydrogen releasing from ammonia borane

Silica hollow nanospheres (SHNS) are used as new nanoscaffold materials to confine ammonia borane (NH(3)BH(3), AB) for enhancing the dehydrogenation process. Different loading levels of AB in SHNS are considered and AB/4SHNS (with AB content of approximately 20 wt%) shows the best result. The onset temperature of the dehydrogenation of AB in SHNS is as low as 70 °C with the peak temperature at 99 °C and no other gases such as borazine and ammonia are detected. Furthermore, within 60 min at 85 °C, 0.53 equivalent of hydrogen is released and the activation energy is 97.6 kJ mol(-1). Through FT-IR, Raman spectrum and density functional theory (DFT) calculation, it is found that nanoconfinement effect combined with SiO-HH-B interaction is essential for the enhancement of hydrogen releasing.     

Alumina-supported cobalt phosphide as a new catalyst for preferential CO oxidation at high temperatures

Abstract

Novel alumina-supported cobalt phosphide catalysts (designated as CoP-3, CoP-10, CoP-20 and CoP-40) prepared from the precursors with Co loadings of 3, 10, 20 and 40?wt% by H₂-temperature-programmed reaction were investigated as potential catalysts for preferential CO oxidation (PROX) in excess H₂ at high temperatures. It was found that the catalytic activities of these Co₂P/γ-Al₂O₃ catalysts were related to their Co loadings. The CoP-10 catalyst showed the best PROX performance in temperature range of 220–240?°C, which was attributed to its optimal microstructures (high surface area, small particle size and big amount of active site).     

笔法与结构对楷书文字美学品质影响的量化研究

笔法与结构对文字观感的影响是中国书法文化的重要研究命题,也与数字书法领域审美评价技术相关联。但以往对该命题主要为定性讨论。本文结合计算机样条曲线及审美量表等技术,设计了一种实验方法对其进行量化研究。首先,选取78个高频字的6种有代表性的楷书体文字作为样品,自编软件并招募测试人员对其标注结构特征点,并用参数曲线建模输出“去除笔法”后的样品图,再进一步经严格定义的“统一结构”操作进行处理,共获得3组样品图,每组468幅。然后,编制审美量表,招募测试者以随机分配的方式对3组样品评测美感和风格。最后,对评测数据进行统计分析。结果显示,对于楷书文字的风格而言,笔法的影响远高于结构;对于文字的美感而言,笔法的作用也大于结构,但影响有限。该结果局限于实验选定的几种经典的楷书文字,且其定义的“去除笔法”和“统一结构”并不能完全涵盖以往经验理论中的相关概念范围。研究表明,自然学科的方法可用于研究书法学中的命题。     

(S)-2-烷基-四氢吡咯[1,2-e]咪唑-1,3-二酮的合成

从L-脯氨酸出发,经三步简单反应制得一种咪唑烷酮衍生物(S)-2-烷基-四氢吡咯[1,2-e]咪唑-1,3-二酮,并通过1 H NMR、13 C NMR、MS等方法对中间产物和目标产物的结构进行了表征,通过X-射线单晶衍射分析确定了(S)-2-环己基-四氢吡咯[1,2-e]咪唑-1,3-二酮的晶体结构.     

H/Al共掺杂对ZnO基透明导电薄膜光电性质和晶体结构的影响

利用H在ZnO中作为浅施主杂质的特性,研究了H掺杂对ZnO：Al透明导电薄膜特性的影响。通过降低ZnO：Al中Al的含量并同时引入H掺杂,解决了透明导电薄膜中高导电性与高透过率之间的矛盾。H的掺杂可以显著降低ZnO基透明导电薄膜的电阻率,这是由于H一方面作为施主可以提供电子从而提高了自由载流子浓度;另一方面与ZnO晶界中的O^-结合降低了晶界势垒,提高了载流子迁移率。利用H掺杂,可以在Al掺杂量降低10倍的情况下,仍然能获得低电阻率（6.3×10^-4 Ω·cm）的透明导电薄膜,同时其近红外波段（1 200 nm）透光率从64%提高到90%。这种具有高导电性和高透光性的透明导电薄膜可以应用于各类薄膜太阳能电池中以提升器件效率。     

Er3+掺杂硫系玻璃微球在980nm激光泵浦下的荧光特性

采用玻璃粉料高温漂浮熔融法制备了0.9%Er₂S₃（质量分数）：75%GeS₂-15%Ga₂S₃-10%CsI（摩尔分数）硫系玻璃微球,并用熔融拉锥法制备了锥腰直径为2.31 μm的石英光纤锥。将其与直径119 μm的硫系微球进行耦合,在980 nm 激光泵浦下获得了微球中与Er³⁺：⁴I_13/2→⁴I_15/2跃迁对应的1.54 μm处的荧光光谱。分析了微球和块状玻璃荧光光谱差异的原因,并用Mie散射理论公式对微球荧光光谱共振峰间隔进行了计算。共振峰间隔实验结果与理论计算误差最小仅为0.05%,验证了理论分析的正确性。最后,讨论了微球峰值间隔与泵浦功率的关系,排除了泵浦功率对共振峰间隔的影响。     

Pt/TiO_2复合纳米结构形貌控制及光催化动力学

制备了3种不同形貌的Ti O2结构:纳米杯、(001)纳米片、(100)纳米片,并进一步与Pt纳米粒子复合以去除污水中的有机染料。透射电镜结果证实了3种Ti O2纳米结构的形成,观察到了附着其上的Pt纳米粒子。使用XRD确定了3种Ti O2纳米结构均为锐钛矿相。以罗丹明B作为有机染料,检测了不同形貌Ti O2及其Pt复合物的光催化性能。结果表明:纳米杯状的Pt/Ti O2在罗丹明B溶液中表现出最高降解率,在1.5 h内降解率可达99.1%。同时讨论了Ti O2及其复合物的光降解机理。