Soluble,saturated‐red‐light‐emitting poly(p‐phenylenevinylene) containing triphenylamine units and cyano groups

A conjugated poly(p‐CN‐phenylenevinylene) (PCNPV) containing both electron‐donating triphenylamine units and electron‐withdrawing cyano groups was prepared via Knoevenagel condensation in a good yield. Gel permeation chromatography suggested that the soluble polymer had a very high weight‐average molecular weight of 309,000. A bright and saturated red emission was observed under UV excitation in solution and film. Cyclic voltammetry showed that the polymer presented quasi‐reversible oxidation with a relatively low potential because of the triphenylamine unit. A single‐layer indium tin oxide/PCNPV/Mg–Ag device emitted a bright red light (633 nm). © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3947–3953, 2004     

Yb3+掺杂铝氟磷酸盐玻璃的光谱和激光性能

研究了Yb3 掺杂铝氟磷酸盐 (AFP)玻璃的吸收光谱、荧光光谱 ,测量了Yb3 离子的荧光有效线宽 (Δλeff>5 5nm)以及2 F5 2 能级的荧光寿命 (τmax=2ms)及随掺杂浓度的变化 .应用倒易法计算了Yb3 的发射截面 ,其发射截面可达 0 6 6 82 3pm2 ,且激光增益系数τfσemi达 1 2 89ms.pm2 .评估了Yb3 在AFP玻璃中的激光性能 ,发现其具有较理想的激发态最小粒子数 (0 15 )、饱和抽运强度 (8 3kW cm2 )和最小抽运强度 (1 2 4 5kW cm2 )值及良好的热稳定性 .研究结果表明掺Yb3 氟磷酸盐玻璃是实现高功率超短可调谐激光器的理想增益介质 .     

Synthesis of paramagnetic BODIPY dyes as new double (spin and fluorescence) sensors

Paramagnetic pyrroline and 1,2,3,6-tetrahydropyridine derivatives of BODIPY and their diamagnetic analogs have been synthesized and characterized as novel redox double sensor and cation sensitive reagents.     

Ground-state complex formation of perylene with pyromellitic dianhydride studied by static fluorescence quenching

The association of complex formation with static quenching in CT systems was investigated. Evaluation of the data made evident that the inner filter effect must be allowed for. Time-resolved and temperature-dependent stationary measurements of fluorescence led to the separation of dynamic and static quenching components. The static quenching constant is discussed with respect to the equilibrium constant of complex formation determined by absorption spectroscopy.     

Selective quenching of tryptophanyl fluorescence in bovine serum albumin by the iodide ion

Modified Stern-Volmer equation is obeyed by bovine serum albumin (BSA)-iodide system showing selective quenching of tryptophanyl fluorescence of BSA. The fraction of accessible protein fluorescence is 0.56 and the effective Stern-Volmer constant is 290 M^-1 at pH 7.4 in 0.005 M phosphate buffer at 25°C. Collisional quenching is operative both in the BSA -I⁻¹ system and the model system, tryptophan-I⁻¹. It is supported by the observed relationship between the ratio of quenching rate constants (k _q ) and diffusion coefficients and alsok _q with bulk viscosity.     

碱土金属氟卤化物中的Eu3+的荧光光谱特征

本文系统研究了MFX体系中Eu³⁺荧光光谱特征,着重讨论了X^-,M²⁺及杂质缺陷(主要为O^2-)对Eu³⁺发光的影响.     

Application of x-ray fluorescence analysis to investigation of the composition of gunshot residues

We have used x-ray fluorescence analysis to study the elemental composition of gunshot residues from smooth-bore and rifled-bore guns. We have established that it is possible to differentiate between types of projectiles (jacketed/lead), types of primers (corrosive/noncorrosive), and types of propellant powders (black/smokeless) by analysis of the elemental composition of the gunshot residues. We have shown that the mercury content in gunshot residues on the surface of the object carrying the residues steadily decreases as storage time increases. Despite this fact, mercury can be preserved as a component of gunshot residues on the object (cotton cloth) under room conditions for more than 45 days. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 320–325, May–June, 2006.     

Surface polarity of cellulose derivates observed by coumarin 151 and 153 as solvatochromic and fluorochromic probes

Solvent‐dependent ultraviolet–visible (UV–vis) absorption and Stokes shifts including strong hydrogen‐bond‐donating (HBD) solvents such as 2,2,2‐trifluoroethanol and 1,1,1,3,3,3‐hexafluoro‐2‐propanol of two coumarine dyes (Co 151 and Co 153) were analyzed with multiple‐square analyses of linear solvation energy relationships and the Kamlet–Taft solvent parameter set to α (HBD capacity), β (hydrogen‐bond‐accepting capacity), and π* (dipolarity/polarizability). The UV–vis absorption and emission spectra of Co 151 and Co 153 were measured when adsorbed on various polysaccharides such as different cellulose batches, carboxymethylcelluloses with different degrees of substitution, and chitine. As a result of this evaluation, Co 153 is recommended as an alternative UV–vis probe for evaluating the dipolarity/polarizability of cellulose and cellulose derivates. Multiple adsorption of Co 153 on Linters cellulose took place indicating a wide‐surface polarity distribution, which makes the determination of a rigid polarity parameter questionable. Thus, fluorescence measurements of adsorbed Co 153 are suitable to detect inhomogenities on a surface but not for the determination of empirical polarity parameters. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1210–1218, 2003