Iridium-Catalyzed Domino Hydroformylation/Hydrogenation of Olefins to Alcohols: Synergy of Two Ligands

A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.     

用于油/水分离的环保无氟超疏水织物的制备与性能

针对目前用于油/水分离的超疏水材料普遍存在的原料不环保、不可降解、涂层耐久性差等缺点,采用简便的浸渍法,制备了一种环保、工艺简单且性能优良的超疏水材料。首先,使用水性聚氨酯（WPU）将聚甲基丙烯酸甲酯-甲基丙烯酸缩水甘油酯P（MMA-r-GMA）微球固定在棉织物表面,构造微纳米级粗糙结构。其次,通过水解-缩合反应,将无毒的十六烷基三甲氧基硅烷（HDTMS）与甲基三乙氧基硅烷（MTES）锚定在棉织物表面,制备得到超疏水棉织物。结果表明,改性棉织物接触角最高可达157.3（°）,滚动角为5（°）。同时具有很好的耐溶剂性,在酸碱溶液中浸泡30 min后,接触角几乎无变化。油水分离效率最高可达97.8%,即使在经过10次循环分离之后,油水分离效率仍然在95%以上。该超疏水织物具有出色的油水分离效率和优良的稳定性,可用于可持续且环保的油水分离领域。     

高校化学教学实验室小型试剂库改造

目前高校化学教学实验室小型试剂库(暂存库)存在较多安全隐患,但一般体量较小,容易被相关管理者忽视,可能会造成实验室安全事故的发生。本文结合国家级实验教学示范中心(中国科学技术大学)化学实验教学实验室的实际情况,阐述了化学教学实验室小型试剂库改造的实践经验,为其他高校实验室试剂库的改造提供符合法律法规和国家标准要求的、适应面广、操作性强的可借鉴经验。     

融入统筹理念的分析化学实验教学

基于一流创新人才培养的要求和分析化学实验课程的特点,介绍了如何在分析化学实验教学中融入统筹学理念,旨在培养学生的统筹能力,拓展化学实验课程的育人功能,实现知识技能传授和综合能力培养并重的教学目的,将创新人才培养的教学理念落到实处。     

烯碳材料改性有机高性能纤维：制备、性能及应用

有机高性能纤维是全球化纤工业的重要发展方向之一。提升现有纤维力学性能的同时研发新型结构功能一体化的纤维对提升我国在航天航空等领域的国际地位具有重要意义。以石墨烯和碳纳米管为代表的烯碳材料具备优异的力、电、热学等性能,可用于改性传统有机高性能纤维。通过制备不同物化性质的烯碳材料并设计合理的改性方式,可将烯碳材料优异的性能传递到传统纤维中,形成具备更高力、电、热学等性能的烯碳材料改性有机高性能纤维。本文首先综述了烯碳材料改性有机高性能纤维的制备方式,包括烯碳材料的分散与功能化、烯碳材料对有机高性能纤维的改性方法,阐述了烯碳材料改性有机高性能纤维的力、电、热学等性能以及烯碳材料的增强机理,进而总结了烯碳材料改性有机高性能纤维的应用,并对其现存的挑战和未来的发展做出展望。     

液态金属原位引发制备半互穿网络水凝胶构建低污染电化学传感界面

复杂组分在传感界面的非特异性吸附会严重影响传感器的灵敏度与准确度。虽然构建致密的亲水性抗污涂层能够抑制表面非特异性吸附,但是其绝缘性又会显著增大传感界面阻抗,严重削弱响应电流。因此,如何兼顾传感界面抗污性与导电性,构建灵敏的传感基底是电化学免疫传感器目前急需解决的关键问题。为此,利用镓化铟液态金属（Liquid Metal, LM）原位引发乙烯基吡咯烷酮（N-vinylprrolidone, NVP）聚合,同时利用壳聚糖（Chitosan, CS）与聚乙烯基吡咯烷酮（poly（N-vinylprrolidone）, pNVP）之间强烈的氢键结合作用,再分步交联成功获得一种半互穿网络水凝胶传感界面,并以此构建电化学免疫传感器。研究表明,所构建的传感器能够对胃动素实现灵敏检测,线性范围为10 pg/mL~10 μg/mL,检测限为6.91 pg/mL（S/N=3）,并且在5%的血清样品中检测结果不受影响。此外,所构建的免疫传感器也显示出优异的重复性、稳定性和选择性。以上结果成功证明了基于液态金属纳米复合凝胶作为电化学传感基底的可行性,也为其它电化学免疫传感器的构建提供重要的借鉴意义。     

外电场作用下离子液体振动光谱变化的分子动力学模拟研究

Vibrational spectroscopy is a powerful tool for studying the microstructure of liquids, and anatomizing the nature of the vibrational spectrum (VS) is promising for investigating changes in the properties of liquid structures under external conditions. In this study, molecular dynamics (MD) simulations have been performed to explore changes in the VS of 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF₆]) ionic liquid (IL) under an external electric field (EEF) ranging from 0 to 10 V·nm^-1 at 350 K. First, the vibrational spectra for [Emim][PF₆] IL as well as its cation and anion are separately obtained, and the peaks are strictly assigned. The results demonstrate that the VS calculated by MD simulation can well reproduce the main characteristic peaks in the experimentally measured spectrum. Then, the vibrational spectra of the IL under various EEFs from 0 to 10 V·nm^-1 are investigated, and the intrinsic origin of the changes in the vibrational bands (VBs) at 50, 183, 3196, and 3396 cm^-1 is analyzed. Our simulation results indicate that the intensities of the VBs at 50 and 183 cm^-1 are enhanced. In addition, the VB at 50 cm^-1 is redshifted by about 16 cm^-1 as the EEF is varied from 0 to 2 V·nm^-1, and the redshift wavenumber increases to 33 cm^-1 as the EEF is increased to 3 V·nm^-1 and beyond. However, the intensities of the VBs at 3196 and 3396 cm^-1 show an obvious decrease. Meanwhile, the VB at 3396 cm^-1 is redshifted by about 16 cm^-1 when the EEF increases to 3 V·nm^-1, and the redshift increases to 33 cm^-1 with an increase in the EEF beyond 4 V·nm^-1. The intensity of the VB at 50 cm^-1 increases because of the increase in the total dipole moment of each anion and cation (from 4.34 to 5.46 D), and the redshift is attributed to the decrease in the average interaction energy per ion pair (from -378.7 to -298.0 kJ·mol^-1) with increasing EEF. The intensity of the VB at 183 cm^-1 increases on account of the more consistent orientations for cations in the system with increasing EEF. The VB at 3196 cm^-1 weakens visibly because a greater number of hydrogen atoms appear around the carbon atoms on the methyl/ethyl side chains and the vibrations of the corresponding carbon-hydrogen bonds are suppressed under the action of the EEF. Furthermore, the intensity of the VB at 3396 cm^-1 decreases due to the decrease in the intermolecular ⁺C-H···F^- hydrogen bonds (HBs), while the relaxation effect that is beneficial for the formation of HBs simultaneously exists in the system under the varying EEF, thus causing a redshift of the VB at 3396 cm^-1.     

数字微光器件研究进展

数字微光器件作为新一代微光夜视装备的核心器件,相比于传统真空微光器件因具有数字化输出的优势而备受各国重视。本文综述了低照度CCD(charge-coupled devices)/CMOS(complementary metal oxide semiconductor)、科学级CMOS、像增强型CCD/CMOS、电子倍增CCD及电子轰击APS(active pixel sensor)/CCD等数字微光器件的研究现状,分析了数字微光器件的应用情况。最后,提出了微光技术和数字微光器件的发展趋势。     

针对多散斑图的差分压缩鬼成像方案研究

鬼成像方案实现所需设备、成像的质量以及成像所花的时间是决定鬼成像技术可实用化的重要因素. 本文提出一种针对多散斑图的差分压缩鬼成像方案. 该方案通过连续探测多个独立的散斑图, 降低了热光鬼成像方案对探测器高时间分辨力的要求; 通过采用差分方法, 抑制了背景噪声和其他噪声源的干扰; 通过使用压缩感知重建算法, 有效地降低了鬼成像所需时间并同时提升成像的质量. 数值仿真结果表明, 对于二灰度“N” 图, 本方案在8000次的采样情形下与多散斑图鬼成像方案35000次采样的结果相比, 均方误差降低了96.9%、峰值信噪比提升15.1 dB. 对于八灰度“Pepper”图, 本方案与多散斑图鬼成像方案相比, PSNR提升11.4 dB. 本方案可降低探测设备的要求、提高成像质量、降低重建时间, 具有广阔的应用前景.     

高效率内腔式2 μm简并光学参量振荡器

报道了一种高效率的2 μm光学参量振荡器. 利用1.064 μm声光调Q Nd:YVO₄激光器抽运基于氧化镁掺杂周期性极化铌酸锂的内腔式光学参量振荡器, 在简并状态实现了稳定高效的2 μm激光输出. 当808 nm激光二极管抽运功率为20 W, Q开关工作频率为15 kHz时, 产生了平均功率为3.5 W、脉冲宽度为1.4 ns的2 μm激光, 光-光转换效率为17.5%, 斜效率为25%. 据我们所知, 该转换效率在2 μm波段内腔式光学参量振荡器中是最高的.