溶液相变对β胡萝卜素溶质的紫外-可见吸收和共振拉曼光谱的影响

测量了β-胡萝卜素溶解在环己醇中65~2℃范围内的紫外-可见吸收与共振拉曼光谱。溶液在20℃时转为固态。随着温度的降低,相变时吸收光谱产生较大蓝移。虽然相变后吸收光谱、拉曼光谱仍红移,拉曼散射截面仍增加,拉曼谱带线宽仍减小,但相变后的光谱随温度的变化却大幅增加。这主要是由于固相中的β胡萝卜素分子的π电子能隙对碳碳键振动调制作用增强所致。文中对这些物理现象给予了解释。     

光纤共振拉曼光谱法痕量分析研究

在液芯光纤内产生共振拉曼效应,可以提高拉曼光谱强度１０＾９倍。样品（被测物）的浓度、模吸收系数、光散射系数和模耦合系数决定光纤最佳长度。该技术分子光谱研究提供了一种新实验方法,在痕量分析、液体中少量分子相互作用研究等方面有很大的应用潜力。低浓度的β－胡萝卜素（β－ｃａｒｏｔｅｎｅ）在ＣＳ２中和Ｉ２在ＣＳ２中的拉曼光谱被得到,其浓度分别是１×１０＾－１３ｍｏｌ／Ｌ和１×１０＾－１４ｍｏｌ／Ｌ。     

超声波强化煤泥浮选脱硫研究

叙述了超声波在选矿工程中的应用,研究了超声波处理对矿浆颗粒性质变化、矿浆中溶解氧和矿浆ｐＨ值的影响,探索了超声强化浮选脱硫的可行性,提出超声处理矿浆作为一种手段,配合适当的浮选工艺与黄铁矿抑制方法,能达到浮脱硫的最佳效果。     

Excitonic Coupling between B and Q Transitions in Porphyrin Aggregates

The properties of meso-tetraphenylporphine （TPP） aggregates formed in acidic aqueous-organic solutions are investigated by UV-vis spectroscopy. According to the absorption spectra, the Q band absorption of the aggregated TPP shows red shift and intensity enhancement, and a model that includes the participation of water molecules in a porphyrin aggregation complex is proposed, then a qualitative explanation based on Gouterman＇s excition coupling theory is presented. Calculations including eigenenergies, eigenstates and the transition dipole strength of the coupled states are carried out.     

CS2中对苯醌n-π*单-三态跃迁的可见吸收光谱及其共振拉曼光谱

测量了对苯醌(p-benzoquinone,PBQ)在CS2中的可见吸收光谱,论证了该实验中发现的507 nm带来源于PBQ的n-π*单-三态跃迁.基于液芯光纤内共振拉曼散射可以提高拉曼光谱强度109倍这一技术,在10-3～10-6 mol·L-1的浓度范围首次探测到514.5 nm激光激发该跃迁而产生的共振拉曼光谱(1 439cm-1).分析认为该谱线来源于PBQ的n-π*单-三态跃迁的羰基伸缩振动(v c-o).实验发现,随着PBQ溶液浓度的降低,该谱线的拉曼频移发生蓝移.文章的研究结果将有助于理解PBQ电子结构与其光物理特性的相互关系,便于获得更丰富的分子结构信息.     

液芯光纤光谱仪

液芯光纤可以使拉曼光谱强度提高103倍。将液芯光纤既作为样品池又作为前置放大系统,研制成功了体积小、重量轻、成本低、灵敏度高的小型拉曼光谱仪。结果表明:通过对液体及溶在液体中的样品进行自发拉曼光谱、共振拉曼光谱的测量,获得了理想的拉曼光谱。     

The effect of anti-hydrogen bond on Fermi resonance: A Raman spectroscopic study of the Fermi doublet ν1—ν12 of liquid pyridine

The effects of anti-hydrogen bond on the ν₁—ν₁₂ Fermi resonance (FR) of pyridine are experimentally investigated by using Raman scattering spectroscopy. Three systems, pyridine/water, pyridine/formamide, pyridine/carbon tetrachloride, provide varying degrees of strength for the diluent-pyridine anti-hydrogen bond complex. Water forms a stronger anti-hydrogen bond with pyridine than with formamide, and in the case of adding non-polar solvent carbon tetrachloride, which is neither a hydrogen bond donor nor an acceptor and incapable of forming hydrogen bond with pyridine, the intermolecular distance of pyridine will increase and the interaction of pyridine molecules will reduce. The dilution studies are performed on the three systems. Comparing with the values of Fermi coupling coefficient W of the ring breathing mode ν ₁ and triangle mode ν ₁₂ of pyridine at different volume concentrations, which are calculated according to the Bertran equations, in three systems, we find that the solution with the strongest anti-hydrogen bond, water, shows the fastest change in the ν₁—ν₁₂ Fermi coupling coefficient W with the volume concentration varying, followed by the formamide and carbon tetrachloride solutions. These results suggest that the stronger anti-hydrogen bond-forming effect will cause a greater reduction in the strength of the ν₁—ν₁₂ FR of pyridine. According to the mechanism of the formation of anti-hydrogen bond in the complexes and the FR theory, a qualitative explanation for the anti-hydrogen bond effect in reducing the strength of the ν₁—ν₁₂ FR of pyridine is given.     

外场对π电子能隙调制C==C，C-C伸缩振动的影响

共振拉曼光谱是研究线性多烯分子的主要分子光谱技术。该技术完美地表征了π电子能隙对C==C,C-C伸缩振动的调制规律。这种调制是通过电子-声子耦合完成的。改变外界环境,能隙调制作用将受到影响。测量了溶剂中β-胡萝卜素分子在温度、压力、溶剂效应、相变等不同环境影响下的吸收光谱、共振拉曼光谱,研究了不同外场对π电子能隙调制C==C,C-C伸缩振动的影响机理及规律。结果表明,在外场影响下,体系的能量降低,π电子能隙(π-π*)减小会使调制增强。即电子-声子耦合增强,使拉曼强度增加,谱线红移。对理解共振拉曼物理过程,认识线性多烯分子的结构,性能有重要意义,对研制优质光电器件也有参考价值。     

基于无源超高频射频识别标签的湿度传感器设计

针对无源超高频射频识别传感器标签大规模运用的需求,采用中芯国际0.35μm互补金属氧化物半导体(CMOS)工艺设计并制造了一种低成本、低功耗的湿度传感器.湿度传感器单元采用聚酰亚胺作为感湿材料,利用顶层金属层制作叉指结构电极,制造过程与标准CMOS制造工序兼容,无需任何后处理工艺.接口电路部分基于锁相环原理,采用全数字电容.数字直接转换结构,能够工作在接近工艺阈值电压下.后期测试结果显示,该湿度传感器在常温下灵敏度为36.5 fF%RH,最大回滞偏差为7%,响应时间为20 ms,0.6 V电源电压下消耗2.1μW功率.     

共振拉曼光谱方法研究生长期与光照对树椒果实β-胡萝卜素含量的影响

利用共振拉曼光谱技术,在体测量了室内盆栽树椒果实的拉曼光谱.实验结果表明,树椒果实的β-胡萝卜素含量随成熟期临近而增加,成熟期后(约45天)达最高值;没受光照的树椒果实β-胡萝卜素含量明显低于接受阳光照射的果实含量;生长(成熟)前期受阳光照射部位由黄白色变为紫色,其β-胡萝卜素含量高于其他部位.本文为在体分析水果蔬菜中β-胡萝卜素含量提供了方法和依据,也验证了阳光在植物生长中的作用.