二苯磷酰基取代四苯基硅的合成及在构筑宽禁带聚合物中的应用

设计并合成了二苯磷酰基取代的四苯基硅基团,并将其作为宽禁带聚合物母体材料构筑基元,通过Suzuki反应偶连3,6位取代的咔唑合成了聚合物SiCzP.对聚合物的结构进行了系统的表征.与模型聚合物SiCz相比,二苯磷酰基的强吸电子能力,降低聚合物母体材料的LUMO能级,更有利于电子的注入.SiCzP与SiCz的玻璃化转变温度分别为219与227℃,失重5%时的分解温度分别为441与426℃.二者均具有良好的成膜性,掺杂器件初步结果表明,二苯磷酰基的引入使器件的亮度和效率都得到提高,其最大流明效率和功率效率比SiCz分别提高了98%和75%.     

基于闭环二苯醚与磷氧基团的主体材料的合成及其在蓝色磷光有机发光二极管中的应用

本文通过多步有机反应制备了化合物9-苯基-9′-（4-二苯基氧化膦）苯基-氧杂蒽[diphenyl（4-（9-phenyl-9H-xanthen-9-yl）phenyl）phosphine oxide,DPPO],低温磷光发射光谱测试表明该化合物具有高的三线态能级（2.88eV）,它可以作为天蓝色磷光发光材料双（4,6-二氟苯基吡啶-N,C2）吡啶甲酰合铱[bis（3,5-difluoro-2-（2-pyridyl）phenyl-（2-carboxypyridyl）iridium（Ⅲ）,FIrpic,ET=2.62eV]的主体材料.将主体材料DPPO用于蓝色磷光有机发光二极管中,该器件在100cd/m2的亮度下,电流效率和流明效率分别达到30.6cd/A和19.2lm/W,最大外量子效率达到13.6%.     

酒石酸铅锆的制备、表征及其燃烧催化作用

以酒石酸、硝酸氧锆和硝酸铅为原料,合成出了双金属盐酒石酸铅锆,采用有机元素分析、X射线荧光光谱和FTIR对其进行了表征。在程序升温条件下,利用TG/DTG、DSC、固相原位反应池/FTIR联用技术,研究了酒石酸铅锆的热行为和热分解机理,描述了酒石酸铅锆的热分解过程,分析得出其最终分解产物为ZrO2、PbO和C。利用螺压工艺制备了含酒石酸铅锆的推进剂样品,研究了酒石酸铅锆对双基系推进剂燃烧性能的影响,分析了其燃烧催化作用。结果表明,酒石酸铅锆对双基系推进剂的燃烧具有良好的催化作用,是一种高效的燃烧催化剂;酒石酸铅锆热分解的最终产物PbO是催化燃烧的主要活性物质,推进剂燃烧过程中形成了氧化铅-铅循环催化体系,而锆和碳则起辅助催化的作用。     

核电站电缆料的制备技术及研究进展

能源短缺已成为全球性问题,利用核能发电已经成为解决能源短缺的重要途径之一。核电的发展为核电站电缆料带来了广阔的发展空间。积极研究、开发及应用核电站电缆料对于我国的核能利用具有重要意义。本文介绍了核电站电缆料的种类、性能、生产方法和国内外的研究现状,并对核电站电缆料的发展趋势做了展望。     

High Crystalline Prussian White Nanocubes as a Promising Cathode for Sodium‐ion Batteries

Prussian blue and its analogues (PBAs) have been recognized as one of the most promising cathode materials for room‐temperature sodium‐ion batteries (SIBs). Herein, we report high crystalline and Na‐rich Prussian white Na₂CoFe(CN)₆ nanocubes synthesized by an optimized and facile co‐precipitation method. The influence of crystallinity and sodium content on the electrochemical properties was systematically investigated. The optimized Na₂CoFe(CN)₆ nanocubes exhibited an initial capacity of 151 mA h g^?1, which is close to its theoretical capacity (170 mA h g^?1). Meanwhile, the Na₂CoFe(CN)₆ cathode demonstrated an outstanding long‐term cycle performance, retaining 78 % of its initial capacity after 500 cycles. Furthermore, the Na₂CoFe(CN)₆ Prussian white nanocubes also achieved a superior rate capability (115 mA h g^?1 at 400 mA g^?1, 92 mA h g^?1 at 800 mA g^?1). The enhanced performances could be attributed to the robust crystal structure and rapid transport of Na ions through large channels in the open‐framework. Most noteworthy, the as‐prepared Na₂CoFe(CN)₆ nanocubes are not only low‐cost in raw materials but also contain a rich sodium content (1.87 Na ions per lattice unit cell), which will be favorable for full cell fabrication and large‐scale electric storage applications.     

Metal Oxide‐Coated Three‐Dimensional Graphene Prepared by the Use of Metal–Organic Frameworks as Precursors

A simple method for the preparation of metal‐oxide‐coated three‐dimensional (3D) graphene composites was developed. The metal–organic frameworks (MOFs) that served as the precursors of the metal oxides were first synthesized on the 3D graphene networks (3DGNs). The desired metal oxide/3DGN composites were then obtained by a two‐step annealing process. As a proof‐of‐concept application, the obtained ZnO/3DGN and Fe₂O₃/3DGN materials were used in a photocatalytic reaction and a lithium‐ion battery, respectively. We believe this method could be extended to the synthesis of other metal oxide/3DGN composites with 3D structures simply through the appropriate choice of specific MOFs as precursors.     

基于核酸探针的光学传感方法和细胞成像研究

许多疾病的特征在于各种生物分子表现出的异常活性,这些物质通常在细胞内外显示过表达现象,因此对其灵敏靶向识别可以提供诊断和治疗效用。由于基因诊疗和化学传感技术的发展,用于灵敏检测细胞内外生物化学物质的核酸探针突显优势。核酸探针可以在稳定进入细胞的同时,特异性地结合目标物质,通过光学方法检测或通过成像技术标识出来。本文综述了采用光学传感方法和成像技术,基于核酸探针检测生物分子的新进展。根据检测对象进行分类,概括分析了几个代表性体系:核酸序列、蛋白质和酶、化学物质和物理化学条件,并详细阐述其关键设计原理、灵敏度及样品检测等结果,同时指出了各类核酸探针的优缺点。     

Trigger bond analysis of nitroaromatic energetic materials using wiberg bond indices

The identification of trigger bonds, bonds that break to initiate explosive decomposition, using computational methods could help direct the development of novel, “green” and efficient high energy density materials (HEDMs). Comparing bond densities in energetic materials to reference molecules using Wiberg bond indices (WBIs) provides a relative scale for bond activation (%ΔWBIs) to assign trigger bonds in a set of 63 nitroaromatic conventional energetic molecules. Intramolecular hydrogen bonding interactions enhance contributions of resonance structures that strengthen, or deactivate, the C NO₂ trigger bonds and reduce the sensitivity of nitroaniline‐based HEDMs. In contrast, unidirectional hydrogen bonding in nitrophenols strengthens the bond to the hydrogen bond acceptor, but the phenol lone pairs repel and activate an adjacent nitro group. Steric effects, electron withdrawing groups and greater nitro dihedral angles also activate the C NO₂ trigger bonds. %ΔWBIs indicate that nitro groups within an energetic molecule are not all necessarily equally activated to contribute to initiation. %ΔWBIs generally correlate well with impact sensitivity, especially for HEDMs with intramolecular hydrogen bonding, and are a better measure of trigger bond strength than bond dissociation energies (BDEs). However, the method is less effective for HEDMs with significant secondary effects in the solid state. Assignment of trigger bonds using %ΔWBIs could contribute to understanding the effect of intramolecular interactions on energetic properties. © 2018 Wiley Periodicals, Inc.     

羟烷基壳聚糖制备及应用研究进展

壳聚糖是由甲壳素通过脱乙酰作用得到的一种天然高分子多糖,具有良好的生物相容性、抗菌性、无毒和可生物降解等优点,但壳聚糖水溶性差限制了其在很多方面的应用。为克服壳聚糖在水溶性上的不足,利用壳聚糖结构中氨基和羟基上的活泼氢进行化学改性以引进羟烷基等亲水性基团成为重要手段。本文主要对壳聚糖羟烷基化改性的方法及羟烷基壳聚糖在医药、水处理和组织工程材料等领域的研究和应用现状进行介绍,并对羟烷基壳聚糖未来的发展趋势进行了展望。     

High‐Performance Magnetic Refrigerant Featuring One‐Dimensional Gd‐O Chains and O‐Gd3 Triangles

Magnetic cooling at low temperature has attracted intensive interest in cryogenics research, which may become important as cooling medium for long‐wave photon detectors to support space exploration. Here, we report a Gd‐based quaternary magnetic refrigerant material, Gd₅BSi₂O₁₃, containing chains of face‐shared GdO₉ polyhedra and geometrically frustrated OGd₃ triangles. Magnetic measurements indicate that Gd₅BSi₂O₁₃ exhibits a large magnetocaloric effect (MCE) about 1.74 times that of the practical magnetic refrigerant GGG (−ΔS_m=67.0 J kg⁻¹ K⁻¹). We analyzed the origin of the large MCE by comparing Gd^III‐containing compounds with different structures and concentrations of Gd^III.