凝聚态化学研究中的动力学振动光谱理论与技术

化学变化的本质是化学键的形成与断裂。凝聚态化学的主要特征是分子内的物理与化学过程与周围环境之间的动态相互作用和动力学耦合,不仅会影响化学键形成与断裂的化学反应平衡与反应速率,还会改变化学反应的走向。动力学振动光谱技术是探测凝聚态体相中与表面上各种微观分子细节最为有力的当代谱学表征技术之一。与脉冲核磁技术类似,科学家们使用一组精心设计的激光脉冲在凝聚态体系中激发复杂的光学响应,所产生的信号中包含了比传统吸收光谱丰富得多的反应机理、分子与溶液结构、分子运动、电荷与能量传递等微观信息。近年来,各种动力学振动光谱被运用于凝聚态化学的各个领域,尤其是在溶液态和表界面态领域,获得了一系列突破性进展,并且处于不断发展的过程之中。在本文中,我们将回顾及展望动力学振动光谱技术的基本概念、实验方法和理论框架,以及它们在凝聚态及表面态化学中的重要应用。     

Solid Amine Adsorbent Prepared by Molecular Imprinting and Its Carbon Dioxide Adsorption Properties

A carbon dioxide imprinted solid amine adsorbent (IPEIA‐R) with polyethylenimine (PEI) as a skeleton was conveniently prepared by using glutaraldehyde to cross‐link carbon dioxide‐preadsorbed PEI. As confirmed by FTIR, FT‐Raman, and ¹³C NMR spectroscopy, CO₂ preadsorbed on PEI could occupy the reactive sites of amino groups and act as a template for imprinting in the cross‐linking process. The imino groups formed from the cross‐linking reaction between glutaraldehyde and PEI could be reduced by NaBH₄ to form CO₂‐adsorbable amino groups. The adsorption results indicated that CO₂ imprinting and reduction of imino groups by NaBH₄ endowed the adsorbent with a higher CO₂ adsorption capacity. Compared with PEI‐supported mesoporous adsorbents, the solid amine adsorbent with PEI as a skeleton can avoid serious pore blockage and CO₂ diffusion resistance, even with a high amine content. The solid amine adsorbent with PEI as a skeleton showed a remarkable CO₂ adsorption capacity (8.56 mmol g^?1) in the presence of water at 25 °C, owing to the high amine content and good swelling properties. It also showed promising regeneration performance and could maintain almost the same CO₂ adsorption capacity after 15 adsorption–desorption cycles.     

Bi-2223/Ag异质结的光生电压效应研究

在50 ～ 340 K不同温度下,利用紫色激光(λ=405 nm)对银/铋锶钙铜氧2223异质结界面进行辐照,观测到明显的光生电压效应,发现光生电压的极性分别在超导转变温度TC与320 K附近发生了反转,排除了激光产生的热电势是产生光生电压的原因,分析表明银/铋锶钙铜氧2223异质结界面处存在内建电场:光生电压由异质结界面处的内建电场分离光生电子-空穴对产生的.超导转变温度TC之下以及320 K以上,内建电场方向从超导体指向金属电极;超导转变温度TC与反向温度320 K之间,内建电场从金属指向超导体.     

用光波导光模光谱技术研究DNA-DNA结合蛋白相互作用

探讨了应用光波导光模光谱(Optical waveguide lightmode spectroscopy,OWLS)技术研究DNA-DNA结合蛋白相互作用的可行性和灵敏性。以固定在传感器芯片表面的DNA探针为捕捉分子,溶液中同时含有探针结合序列和NF—κB结合位点序列的寡核苷酸与NF-κB亚单位p50同源二聚体形成的DNA-蛋白质复合物为检测分子,用光波导光模光谱检测技术建立非标记DNA-DNA结合蛋白相互作用检测研究体系。利用这一体系对不同样品中NF-κB p50浓度和具不同NF-κB结合位点序列的寡核苷酸与NF-κB p50亲合和力进行检测。样品中低至0．33 nmol/1的NF-κB p50被光波导光模光谱检测出,不同的NF-κB结合序列与NF-κB p50亲合力有显著的差异。研究发现,光波导光模光谱技术可以用于DNA-DNA结合蛋白相互作用研究,所建立的非标记检测研究体系可以进行样品中结合蛋白含量高灵敏检测和核酸序列与结合蛋白的亲合力的检测研究。     

电控聚合物分散液晶变焦全息透镜制作

介绍了相位型全息聚合物分散液晶(PDLC)材料全息透镜,在电场作用下液晶微滴折射率逐渐与聚合物折射率匹配,实现透镜电控变焦。研究了微米尺寸和纳米尺寸液晶微滴聚合物分散液晶材料配方特性和微观结构。采用优化纳米尺寸材料配方制作5~6μm聚合物分散液晶盒,采用离轴式平面波和球面波干涉全息写入光路,成功制作电控变焦聚合物分散液晶全息透镜样品。该透镜样品焦距为20 mm,能够正一级衍射放大成像。实现“0”,“1”变焦的驱动电压阈值为60 V。并进一步提出了基于聚合物分散液晶电控变焦元件集成叠加技术实现电控变焦光学成像系统的技术思路。     

二维导电金属有机骨架材料

金属有机骨架(MOFs)是由金属离子或簇与有机配体以配位键组装而成的晶态多孔材料,其高的孔隙率及功能可设计性使其广泛应用于各种领域.然而,传统MOFs多数电导率非常低,这严重制约了其在电学相关领域的发展.近年来,导电金属有机骨架尤其是二维导电金属有机骨架(2D ECMOFs)材料因其结构中独特的π-π堆积及π-d共轭作...     

求解参数识别反问题的同伦正则化方法

提出了求解参数识别反问题的同伦正则化方法,给出了相应的收敛性定理.数值结果表明该方法是一种快速的大范围收敛方法.     

Long pulse duration of the UV laser with a multi-reflected cavity: Experiment and modeling

The long pulse operation of ultraviolet (UV) laser attributed to multi-reflection is presented on an acousto-optic (AO) Q-switched ultraviolet laser system blocking green light inside a cavity. The ultraviolet laser with the highest average power of 456 mW is obtained with 20 kHz repetition-rate. The numerical simulation of UV pulse broadening was studied using Gaussian curve approximation. The conclusion suggests that the short multi-reflected cavity and high incident pump power will be beneficial to alleviate the width broadening effect. The results, for the first time, would provide the technology for controlling the pulse width of an AO Q-switched DUV laser.     

Light-Driven Syngas Production over Defective ZnIn2S4 Nanosheets

Photocatalytic syngas (CO and H₂) production with CO₂ as gas source not only ameliorates greenhouse effect, but also produces valuable chemical feedstocks. However, traditional photocatalytic systems require noble metal or suffers from low yield. Here, we demonstrate that S vacancies ZnIn₂S₄ (V_S-ZnIn₂S₄) nanosheets are an ideal photocatalyst to drive CO₂ reduction into syngas. It is found that building S vacancies can endow ZnIn₂S₄ with stronger photoabsorption, efficient electron–hole separation, and larger CO₂ adsorption, finally promoting both hydrogen evolution reaction (HER) and CO₂ reduction reaction (CO₂RR). The syngas yield of CO and H₂ is therefore significantly increased. In contrast to pristine ZnIn₂S₄, the syngas yield over V_S-ZnIn₂S₄ can be improved by roughly ≈4.73 times and the CO/H₂ ratio is modified from 1:4.18 to 1:1. Total amount of syngas after 12 h photocatalysis is as high as 63.20 mmol g⁻¹ without use of any noble metals, which is even higher than those of traditional noble metal-based catalysts in the reported literatures. This work demonstrates the critical role of S vacancies in mediating catalytic activity and selectivity, and highlights the attractive ability of defective ZnIn₂S₄ for light-driven syngas production.