Transportation of sulfur mustard (HD) in alkyd coating

The kinetics of absorption, desorption, and degradation of sulfur mustard (HD) in alkyd coating was experimentally studied, and a one-dimension mass transfer model for the transportation of HD molecule in alkyd coating was established on the experimental data. The obtained results indicated that the persistence of HD molecule could be greatly increased due to the absorption of HD droplets by alkyd coating, and there still occurred the desorption of HD as vapor from coating for more than 3 days even after decontamination of HD droplets onto coating. It was also experimentally shown that the majority of HD both absorbed and desorbed was accomplished at an early stage, less than 10 h, and HD molecule was able to be degraded within the alkyd coating probably through the reactions of hydrolysis and elimination. The diffusion coefficient and degradation rate constant of HD in alkyd coating were determined to be practically around 10(-9) cm2/s and 2.4 x 10(-5) min(-1), respectively.     

Selective ring expansion alkylation of formyl[2.2.1]bicyclic carbinols with C-nucleophiles: a unique route to cyclopentane derivatives

Reactions of camphor-, and camphene-derived formyl [2.2.1]bicyclic carbinols with Grignard and organolithium reagents afford the corresponding regio- and stereospecific alkyl/aryl [3.2.1]bicyclic diols. Some of these bicyclic diols have been treated with lead tetraacetate to provide new chiral cyclopentane derivatives. A plausible mechanism of the ring expansion-alkylation reaction is proposed.     

Phosphate-modified TiO2 nanoparticles for selective detection of dopamine, levodopa, adrenaline, and catechol based on fluorescence quenching

For the first time, an aqueous solution, comprising 6-nm phosphate-modified titanium dioxide (P-TiO2) nanoparticles (NPs) and fluorescein, has been used for sensing dopamine (DA), levodopa (L-DOPA), adrenaline, and catechol. The complexes obtained by means of chelation of surface Ti(IV) ions with an enediol group exhibit strong absorption at 428 nm; thus, they can be designed as efficient quenchers for fluorescein. The fluorescence of a fluorescein solution containing 1.4 mM P-TiO2 NPs at pH 8.0 decreases if the solution comprises DA, L-DOPA, adrenaline, and catechol, but not noradrenaline, ascorbic acid, and salicylic acid. We consider that P-TiO2 NPs have a number of advantages over bare TiO2 NPs, such as ease of preparation, high selectivity, and high stability. By measuring fluorescence quenching, the limits of detection at a signal-to-noise ratio of 3 are calculated as 33.5, 81.8, 20.3, and 92.1 nM for DA, L-DOPA, adrenaline, and catechol, respectively. In contrast, UV-vis absorption reveals the relatively poor sensitivity of these compounds. We have validated the applicability of our method by means of analyses of DA in urine samples. High-performance liquid chromatography in combination with an electrochemical cell has been used to further confirm our results. We believe that this approach has great potential for diagnostic purposes.     

掺杂功能磺酸的导电聚苯胺的合成及其红外光谱研究

合成了参杂对甲苯磺酸（ＴＳＡ）,十二烷基苯磺酸（ＤＢＳＡ）,樟脑磺酸（ＣＳＡ）和磺基水杨酸（ＳＳＡ）的导电聚苯胺要品：Ｄｐａｎ／ＴＳ,Ｄｐａｎ／ＤＢＳＡ,Ｄｐａｎ／ＣＳＡ,Ｄｐａｎ／ＳＳＡ,并对这些样品进行了表征,研究了它们的红外光谱特性。     

8-羟基喹啉纤维分离富集-ICP-AES同时测定多种痕量稀土元素

８－羟基喹啉纤维分离富集－ＩＣＰ－ＡＥＳ同时测定多种痕量稀土元素郭伊荇,刘春明,赵晓亮,王为玲（东北师范大学测试中心,长春,１３００２４）关键词８－羟基喹啉纤维滤纸片,稀土元素,电感耦合等离子体原子发射光谱地球化学样品中稀土元素的测定主要采用离子交换...     

Single-Shot Diffusion Measurement in Laser-Polarized Gas

A single-shot pulsed gradient stimulated echo sequence is introduced to address the challenges of diffusion measurements of laser polarized 3He and 129Xe gas. Laser polarization enhances the NMR sensitivity of these noble gases by >10(3), but creates an unstable, nonthermal polarization that is not readily renewable. A new method is presented which permits parallel acquisition of the several measurements required to determine a diffusive attenuation curve. The NMR characterization of a sample's diffusion behavior can be accomplished in a single measurement, using only a single polarization step. As a demonstration, the diffusion coefficient of a sample of laser-polarized 129Xe gas is measured via this method.     

Convergence and Error Bound for Perturbation of Linear Programs

In various penalty/smoothing approaches to solving a linear program, one regularizes the problem by adding to the linear cost function a separable nonlinear function multiplied by a small positive parameter. Popular choices of this nonlinear function include the quadratic function, the logarithm function, and the x ln(x)-entropy function. Furthermore, the solutions generated by such approaches may satisfy the linear constraints only inexactly and thus are optimal solutions of the regularized problem with a perturbed right-hand side. We give a general condition for such an optimal solution to converge to an optimal solution of the original problem as the perturbation parameter tends to zero. In the case where the nonlinear function is strictly convex, we further derive a local (error) bound on the distance from such an optimal solution to the limiting optimal solution of the original problem, expressed in terms of the perturbation parameter.     

Phase studies and thermal stability of binary systems of cholesteric liquid crystals

The binary mixture of cholesteryl oleyl carbonate (COC) and cholesteryl nonanoate (CN) with different ratios has been characterized by differential scanning calorimetry (DSC) to determine the phase diagrams. Their normal shelf-life and accelerated stability studies were also examined. A novel microscopic Fourier-transform infrared (FT-IR) spectrometer equipped with DSC was also used to measure simultaneously the chemical structural variation and the thermal response of these liquid crystals. The results indicate that the binary mixture might transform from smectic to cholesteric and then to isotropic liquid (CN composition <50%); from solid to cholesteric and then to isotropic liquid (CN composition >50%). Therefore, the 50% CN composition might play a critical role in the phase transition of the binary COC-CN mixture. The microscopic FT-IR/DSCsystem could also confirm the phase transition, but could measure the phase trasition temperature of liquid crystals more easily and sharply than the DSC method. The long-term accelerated thermal stability of the COC-CN mixture seemed to be more constant when stored at 4 °C than in any other temperature conditions.     

Synthesis and characterization of novel poly(amide-imide)s containing hexafluoroisopropylidene linkage

A series of novel soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[N-(4-carboxyphenyl)-phthalimidyl]hexafluoropropane, with various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl₂ using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.78–1.63 dL g⁻¹. The polymers were amorphous and readily soluble in aprotic polar solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide as well as in less polar solvents such as pyridine and γ-butyrolactone, and also in tetrahydrofuran. The polymer films had tensile strength of 84–129 MPa, an elongation at break range of 6–22%, and a tensile modulus range of 2.0–2.7 GPa. The glass transition temperatures of the polymers were determined by DSC method and they were in the range of 240–282°C. These polymers were fairly stable up to a temperature around or above 400°C, and lose 10% weight in the range of 450–514°C and 440–506°C in nitrogen and air, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2629–2635, 1999     

Glass transition and miscibility in blends of two semicrystalline polymers: Poly(aryl ether ketone) and poly(ether ether ketone)

Binary melt‐blended mixtures of two aryl ether ketone polymers (i.e., a new poly(aryl ether ketone) (code name PK99) and poly(ether ether ketone) (PEEK), have been studied. Polymer miscibility in glassy amorphous (or melt) domains has been demonstrated for the binary blend comprising of two aryl‐ether‐ketone‐type semicrystalline polymers. Composition‐dependent, single T_g was observed within full composition range in the PK99/PEEK blends, and the narrow T_g breadth also suggests that the scale of mixing was fine and uniform. To better resolve any possible overlapping T_g's, physical aging was imposed on a comparison set of blend samples for the purpose of improving detectability of overlapped multiple transitions if existing. The result still showed one single T_g. The relative sharp T_g and lack of cloud point transition suggest that the scale of molecular intermixing is good. Phase homogeneity was further confirmed using optical and scanning electron microscopy. The X‐ray diffractograms suggest that isomorphism does not exist in the PK99/PEEK blends and that the crystal forms of the respective polymers remain distinct and unchanged by the miscibility in the amorphous region. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1485–1494, 1999