聚2,5-二甲氧基苯胺的合成与表征

报导了聚2，5-二甲氧基苯胺（P25DMAn）的化学与电化学合成，并用元素分析、FTIR、UV－VIS吸收光谱、电导率测定以及电化学等手段对该聚合物进行了表征．P25DMAn类似聚苯胺（PAn）的结构，是由其单体通过氮原子N在对位上键合而成.P25DMAn是一种能溶于多种有机溶剂如THF、CH2Cl2、CHCl3、DMSO、DMF等．并具有极好的环境稳定性，优良的电活性和相当高的电导率的高聚物．因此，P25DMAn是一种很有应用前景的新的导电高聚物．

羟基化SBS嵌段聚合物模板制备银纳米粒子

针对嵌段聚合物合成过程复杂且成本高的问题,以国产SBS(苯乙烯丁二烯苯乙烯嵌段聚合物)为基本原料,通过大分子化学反应,制备得到了羟基化SBS.以羟基化SBS为模板,N,N二甲基甲酰胺(DMF)为溶剂,硝酸银为原料,在一定反应条件下制备得到了银纳米粒子.采用紫外可见吸收光谱及透射电子显微镜对银纳米粒子的尺寸和形貌进行了表征.研究结果表明:所合成的银纳米粒子可以产生纳米银所具有的表面等离子态的特征吸收峰,羟基化SBS可以为银纳米粒子的成核及晶体长大起到较好的模板作用,实验过程中所得到的银纳米粒子具有球状形貌特征,且具有较窄的尺寸分布.

Spectra of Linear Polyene Molecule-canthaxanthin

Raman spectra and ultraviolet-visible（UV-Vis） absorption spectra of linear polyene molecule-canthaxan-thin in n-hexane are measured and analyzed.In addition,the optimized structure of canthaxanthin was calculated via density functional theory（DFT） functional B3LYP.With decreasing the concentration,Raman scattering cross section （RSCS） of fundamental frequency is extremely high,and the UV-Vis absorption bands become narrower.The results of coherent weakly damped electron-Lattice vibration model were analyzed.

Revealing the working mechanism of a multi-functional block copolymer binder for lithium-sulfur batteries

The lithium-sulfur(Li-S)battery is one of the most promising substitutes for current energy storage systems because of its low cost,high theoretical capacity,and high energy density.However,the high solubility of intermediate products(i.e.,lithium polysulfides)and the resultant shuttle effect lead to rapidly fading capacity and a low coulombic efficiency,which hinder the practical application of Li-S batteries.In this study,block copolymers are constructed with both an ethylene oxide unit and a styrene unit and then used as binders for Li-S batteries.Electrochemical performance improvements are attributed to the synergistic effects contributed by the different units of the block copolymer.The ethylene oxide unit traps polysulfide,which bonds strongly with the intermediate lithium polysulfide,and enhances the transport of lithium ions to reach high capacity.Meanwhile,the styrene unit maintains cathode integrity by improving the mechanical properties and elasticity of the constructed block copolymer to accommodate the large volume changes.By enabling multiple functions via different units in the polymer chain,high sulfur utilization is achieved,polysulfide diffusion is confined,and the shuttle effect is suppressed during the cycle life of Li-S batteries,as revealed by operando ultraviolet-visible spectroscopy and S Kedge X-ray absorption spectroscopy.

Mutual influence of copper and paraquat on their adsorption in soil

Paraquat and copper (Cu) are commonly used and detected in soil.Therefore,it is important to understand their mobility in the environment.In this study,the competitive effects of paraquat and Cu on their adsorption in five representative Chinese soils were investigated using batch adsorption equilibrium experiments and spectroscopic analysis.The results showed that the adsorption of paraquat in soil varied with soil type and was positively correlated with both soil cation exchange capacity and organic matter content.Paraquat exerted a more remarkable suppression effect on the adsorption of Cu than Cu on the adsorption of paraquat.In the presence of 0.12 and 0.19 mmol L-1paraquat,Cu adsorption decreased by 16%and 22%in Heilongjiang soil and by 24%and37%in Jiangxi soil,respectively.In the presence of 0.1 and 0.2 mmol L-1Cu,paraquat adsorption decreased by 4%and 8%in Heilongjiang soil and by15%and 19%in Jiangxi soil,respectively.Exchange selectivity involving symmetric cation (paraquat2+and Cu2+) exchange is the probable basis for the suppression effect.The ultraviolet-visible absorption experiments suggested that the formation of Cu-paraquat complexes was unlikely to happen in a solution or at the soil surface.Copper K-edge X-ray absorption spectroscopy indicated that Cu in soil may have some water as hydration layers as the nearest neighbors,and each Cu atom was coordinated with five oxygen atoms.These findings greatly improve our knowledge of the molecular-scale adsorption mechanisms of paraquat and Cu in soil and can be used to predict the behavior,transport,and fate of paraquat and Cu in agricultural soils.

Resonance scattering spectroscopy of gold nanoparticle

The gold nanoparticles in diameter of 10-95 nm have been prepared by Frens procedure, all of which exhibit a resonance scattering peak at 580 nm. The mechanism of resonance scattering for gold nanoparticle has been considered according to the wave motion theory of nanoparticle in liquid. The principle of superamolecular interface energy band(SIEB) has been set up and utilized to explain the relationship between the diameter and colors for gold nanoparticle in liquid. A novel spectrophotometric ruler for the determination of the diameter has been proposed according to the relationship of the maximum absorption wavelength and diameter.

Spectral characteristics of dissolved organic matter in sediment pore water from Pearl River Estuary

As key parts of land-sea transition zones,estuary ecosystems play a very important role in the ocean carbon cycle processes.The sources,degradation,and preservation of dissolved organic matter(DOM)in estuaries have long been the subject of intense study.To examine the aforementioned issues,this study examined three-dimensional fluorescence spectroscopy and ultraviolet-visible absorption spectroscopy to determine the spatial distribution and sources of DOM in the pore water of three sedimentary cores from the Pearl River Estuary(S1,S2 and S3,with increasing salinity).Using the parallel factor analysis(PARAFAC)method to analyze the three-dimensional fluorescence spectrum data,five fluorescent components were obtained—three humic-like components(C1,C3,and C4),and two protein-like components(C2 and C5).C2 exhibited a significant positive correlation with the sediment microbial deoxyribose nucleic acid(DNA)concentration(R~2=0.69,P<0.01),indicating that the protein-like component C2 might be derived from the catabolism of in situ microbes.C5 displayed a relatively weak correlation with DNA concentration(R~2=0.40,P<0.05),presumably due to the incorporation of phenolic compounds,which have a fluorescence peak very similar to that of protein-like components.The source of humic-like fluorescent components is extremely complex.The content at station S1 was relatively high(1.45–8.83 R.U.),which implies that terrestrial inputs had a significant influence.The three humic-like components showed similar distributions at S2 and S3,and the fluorescence intensity was rather low;this result indicates that the DOM at these two stations was more likely affected by the metabolism of algae and microorganisms.The humification index(HIX)and the fluorescence intensity of protein-like components increased and decreased,respectively,with depth.There was a significant positive correlation between the relative content of protein-like components and the spectral slope ratio(SR),which indicates that DOM transitioned from low-molecular-weight protein-like components in the surface sediment to high-molecular-weight humic-like components in the subsurface.This study provides valuable information for understanding the pore water size/reactivity(PWSR)model of DOM and its biochemical processes occurring in estuary sediments.