PARAFAC法解析太湖水体DOM三维荧光光谱

采用平行因子法(PARAFAC法)对太湖水样溶解性有机质(DOM)三维荧光光谱进行解析。通过比较因子数分别为3,4和5时,PARAFAC模型的核一致函数、 激发和发射光谱误差平方和、 各水样模拟的三维荧光光谱和残差谱图等情况,选择因子数为3作为太湖水样DOM三维荧光光谱PARAFAC模型的最佳因子数。太湖水样DOM的3类主要荧光组分分别是类腐殖质荧光物质、 类色氨酸荧光物质、 类酪氨酸荧光物质。     

The pKa theoretical estimation of C―H,N―H,O―H and S―H acids in dimethylsulfoxide solution

A scheme for the pK_a estimation of organic acids in dimethylsulfoxide (DMSO) solution based on quantum chemical calculations is proposed. The procedure of pK_a calculation requires several steps. The first is the calculation of the gas phase acidity of the compound. The G3MP2B3, G4MP2 as well as CBS‐QB3 composite methods made it possible to estimate values of gas phase acidities of an extensive set of structures with a high confidence level (standard deviations equal to 1.15, 1.13 and 1.29 kcal mol^?1, respectively; the test set included 91 compounds). The second step is the computation of the solvation correction with the integral equation formalism version of polarizable continuum model (IEF‐PCM)–B3LYP/6‐311+G(d,p) approximation. Within the bounds of our approach, the medium properties were covered only by the PCM model, i.e. the proposed procedure neglects specific interactions between DMSO and the solute. It was determined that the approach to pK_a estimation mentioned above is the most balanced in terms of accuracy, resource intensity and computation time cost. In the third step, the error of the pK_a calculation was decreased by correlation allowances. Correlation allowances were determined for each acid class (62 С―Н, 55 N―Н, 24 O―Н and 5 S―Н acids) in the range of 50 units in terms of logarithmic scale using the test set including 146 compounds. Seven O―H acids showing the ability to form cyclic dimers were separated into a discrete group. The proposed methodology was applied to the estimation of pK_a for trans‐ and cis‐dimethyl‐4,5‐dihydro‐3H‐pyrazol‐3,5‐dicarboxylates as well as for 5‐fluorouracil subject to competitive dissociation, the latter by N1―H or N3―H bonds. Copyright © 2014 John Wiley & Sons, Ltd.     

偶氮基染料掺杂薄膜的双光子图象存储

研究了偶氮基染料掺杂薄膜ＭＯ－ＰＶＡ和ＥＯ－ＰＶＡ的双光子存储特性。在对薄膜用Ａｒ＾＋激光作预激发下实现了Ｈｅ－Ｎｅ激光的红光存储。获得了实时和短时存储照片。光电记录存储曲线，分析了双光四能级系统的存储机制。实现确定了最佳预激发功率约为０．２８Ｗ／ｃｍ＾２，最小Ｈｅ－Ｎｅ光可存储功率密度低于０．２Ｗ／ｃｍ＾２。     

激光诱导水体频率上转换的荧光发射

用Nd：YAG的二倍频532 nm激光对几种不同水体的激光诱导荧光(LIF)光谱进行了测量,利用特征光谱荧光标记(SFS)技术指认出水体中溶解有机物(DOM)、叶绿素a(Chl a)及类胡萝卜素等物质的特征光谱带。指出在455 nm波长处具有较大强度的荧光峰是附属色素中抗氧化作用的类胡萝卜素(PPC)的贡献。提出了激光诱导PPC荧光频率上转换发射的动力学模型。     

Sonochemical temperature controlled synthesis of pellet-, laminate- and rice grain-like morphologies of a Cu(II) porous metal–organic framework nano-structures

Nano-structures of the Cu(II) metal–organic framework, {Cu(BDT)(DMF)·CH₃OH·0.25DMF}_n (1), which BDT²⁻ is 1,4-benzeneditetrazolate, have been synthesized by the reaction of H₂BDT with Cu(NO₃)₂·6H₂O via ultrasonic irradiation in three different temperatures, which causes different morphologies. The products were characterized by IR spectroscopy, elemental analysis, scanning electron microscopy and X-ray powder diffraction. This study demonstrates that sonochemistry is a suitable method for preparation of metal–organic framework nano-structures and temperature is an effective parameter on morphologies of Cu(II) metal–organic framework nano-structures.     

使用PTB7作为阳极修饰层提高有机发光二极管的性能

采用poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl][3-?uoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]](PTB7)作为有机发光二极管器件的阳极修饰层,制备了结构为indium tin oxide(ITO)/PTB7(不同浓度)/N,N’-Bis(naphthalen-1-yl)-N,N’-bis(phenyl)benzidine(NPB,40 nm)/8-hydroxyquinoline(Alq3,60 nm)/LiF(1 nm)/Al的系列器件,同时研究了不同浓度的PTB7对器件性能的影响.PTB7的最佳浓度为0.25 mg/mL,器件性能得到明显的改善,起亮电压为4.3 V.当驱动电压为14.6 V时,最大亮度为45800 cd/m2,最大电流效率为9.1 cd/A.与没有PTB7修饰的器件相比,其起亮电压降低了1.9 V,最高亮度提升了78.5%.器件性能提高归因于PTB7的插入使得空穴注入和传输能力大大改善.     

基于选择性模型组合的三维荧光光谱水质分析方法

为提高三维荧光光谱水质分析的精度,提出一种选择性模型组合方法,采用相关系数法对三维荧光光谱激发波长进行选择,并将被选中的激发波长下的荧光发射光谱水质分析子模型采用岭回归法进行模型组合,得到对水质指标的组合模型。以一组总有机碳(TOC)范围在3.41～125.35 mg·L-1,化学需氧量(COD)范围在22.80～330.60 mg·L-1的32个地表水和城市生活污水水样做为研究对象,对其三维荧光光谱220～400 nm范围内的10个激发波长采用上述方法进行选择,分别针对TOC和COD指标筛选出260,280,400 nm和220,280,400 nm各3个激发波长。采用部分最小二乘方法建立上述激发波长下荧光发射光谱水质分析子模型,根据岭回归法计算各子模型的组合系数,分别得到对TOC和COD指标的组合模型。实验结果表明：采用该方法得到的组合模型对TOC和COD两种指标的预测误差均方根(RMSEP)相比精度最高的单一荧光发射光谱子模型分别减小了15.4%和17.5%,相比未经模型选择的组合模型分别减小了6.1%和10.9%。     

Atomic force microscopy investigation of growth process of organic TCNQ aggregates on SiO2 and mica substrates

<正>Deposition patterns of tetracyanoquinodimethane(TCNQ) molecules on different surfaces are investigated by atomic force microscopy.A homemade physical vapour deposition system allows the better control of molecule deposition. Taking advantage of this system,we investigate TCNQ thin film growth on both SiO_2 and mica surfaces.It is found that dense island patterns form at a high deposition rate,and a unique seahorse-like pattern forms at a low deposition rate.Growth patterns on different substrates suggest that the fractal pattern formation is dominated by molecule-molecule interaction.Finally,a phenomenal "two-branch" model is proposed to simulate the growth process of the seahorse pattern.     

Control of device performances of phosphorescent white organic light-emitting diodes by managing charge transport properties of host materials

Interlayer-free phosphorescent white organic light-emitting diodes (PHWOLEDs) with a mixed-host emitting structure in red emitting layer were developed and device performances were investigated according to the host composition in the red emitting layer. Device performances could be effectively managed by a simple change of host materials in the red emitting layer. A high quantum efficiency was obtained in PHWOLEDs with electron transport-type host in the red emitting layer and red emission was strong in PHWOLEDs with mixed-host in the red emitting layer. In addition, stable color performances were obtained in electron transport-type host rich devices.