Effects of anion and cation doping on the thermoelectric properties of n-type PbS

The PbCl_xS_1-x and Pb_1-xBi_xS (x? =?0–0.05) bulks were fabricated with a facile method of hydrothermal synthesis and microwave sintering, and the effect of anionic and cationic donors on the thermoelectric performance of PbS was investigated. Although Cl^? and Bi³⁺ both effectively improved the thermoelectric properties of n-type PbS, more excellent thermoelectric performance was obtained from Cl^? doped samples because of higher electrical property and lower thermal conductivity at higher temperature (T? >?600?K). The thermoelectric figure of merit (ZT) reaches 1.04 for PbCl_0.015S_0.985 at 800?K and increases with temperature increasing without sign of saturation, which is probably the highest value ever reported for single-phase polycrystalline n-type PbS. The results also indicate that the hydrothermal synthesis and microwave sintering can realize anion doping as well as cation doping for n-type PbS at low cost, and PbS should be a robust alternative for PbTe thermoelectric materials.     

A Multiscale-Porous Anion Exchange Membrane for Convenient and Scalable Electrokinetic Concentration of Cationic Species

A device able to electrokinetically concentrate cationic samples has many potential medical and industrial applications, but until now has remained undeveloped due to the lack of a commercial anion-permselective material leading to a prohibitively complex fabrication procedure. Herein, a novel multiscale-porous anion exchange membrane (MP-AEM) that enables the convenient and scalable electrokinetic concentration of cationic species is proposed. A mechanically enhanced multiscale-porous structure with a solid framework is realized by adopting polyester resin as an additive to overcome the intrinsic limitations of the AEM material. The scalable MP-AEM-embedded electrokinetic concentrator is devised based on the peculiar properties of the MP-AEM that for allow both ion and fluid transport. With the MP-AEM, the concentrator is fabricated in a highly streamlined manner consisting only of a simple insertion and assembly. The concentration performance of the MP-AEM-embedded electrokinetic concentrator is demonstrated with a positively charged fluorescent dye and a fluorescein-labeled protein, and the results show enrichment factors of 250 and 500, respectively. The MP-AEM makes cationic electrokinetic concentration more accessible and scalable, thereby enabling further progress in a wide range of fields.     

Pu(OH)4(am)与碳酸根的配位行为研究

为了解在惰气环境Pu(OH)_4(am)与碳酸盐溶液中HCO^-₃，CO^2-₃的配位行为，考察了放置时间对Pu总浓度的影响；同时也考察了pH值、碳酸根总浓度变化对碳酸盐溶液中Pu的主要存在形态及溶解总浓度的影响。实验结果表明，HCO^-₃离子与Pu(OH)_4(am)生成[Pu(OH)₄(HCO₃)₂]^2-（lg K=-2.61±0.18, lgβ=54.25±0.18）或[Pu(OH)₂(CO₃)₂]^2-（lgK=-2.61±0.18, lgβ=46.91±0.18）；CO^2-₃离子与Pu(OH)_4(am）生成[Pu(OH)₄(CO₃)₂]^4-（lgK=-3.52±0.11, lgβ=53.33±0.11）。可能的配位反应方程式为： Pu(OH)_4(am)+2HCO^-₃ = [Pu(OH)₄(HCO₃)₂]^2-, Pu(OH)_4(am)+2HCO^-₃ =[Pu(OH)₂(CO₃)₂]^2-+2H₂O, Pu(OH)_4(am)+2CO^2-₃=[Pu(OH)₄(CO₃)₂]^4-。     

Copper(II) removal from aqueous solutions by fly ash

The removal of Cu(II) by adsorption on fly ash has been found to be concentration, pH and temperature dependent. The kinetics of adsorption indicates the process to be diffusion controlled. The Langmuir constants have been calculated at different temperatures, and the adsorption has been found to be endothermic (ΔH = 15.652 kcal mol^?1). The maximum removal is observed at pH 8.0, and variation in adsorption with pH has been explained on the basis of surface ionisation and complexation.     

膜法烯烃/烷烃气体分离的研究进展

对烯烃/烷烃气体分离技术的现状进行了总结，阐述了膜法烯烃/烷烃气体分离的研究进展、分离原理及存在的问题等．同时展望了膜技术应用于烯烃/烷烃气体分离的前景及研究方向．     

Studies on Catalytic Side-Chain Oxidation of Nitroaromatics to Aldehydes with Oxygen

The side-chain oxidation of 2-nitrotoluene in liquid phase in the presence of catalytic amount of manganese sulfate and stoichiometric amount of potassium hydroxide with oxygen was studied. In the most favorable conditions, over 80% of conversion of 2-nitrotoluene and 50% of selectivity to 2-nitrobenzaldehyde was achieved. Effects of the reaction parameters on the conversion of the reactant and the selectivity of the product were examined. These results, together with EPR spectroscopic study, show that a benzyl anion was formed in the early stage of the reaction, which was then converted to the final product via a free radical mechanism.     

液碱纯度对阴床再生运行情况分析

从理论上分析了液碱对阴树脂再生度的影响。通过两种不同纯度的液碱再生阴树脂的实际运行经济指标统计分析，说明用高纯度液碱再生阴树脂，可提高树脂的工作交换容量和周期制水量，有很好的经济效益。     

Solubility and Aggregation of Selected Proteins Interpreted on the Basis of Hydrophobicity Distribution

Protein solubility is based on the compatibility of the specific protein surface with the polar aquatic environment. The exposure of polar residues to the protein surface promotes the protein’s solubility in the polar environment. The aquatic environment also influences the folding process by favoring the centralization of hydrophobic residues with the simultaneous exposure to polar residues. The degree of compatibility of the residue distribution, with the model of the concentration of hydrophobic residues in the center of the molecule, with the simultaneous exposure of polar residues is determined by the sequence of amino acids in the chain. The fuzzy oil drop model enables the quantification of the degree of compatibility of the hydrophobicity distribution observed in the protein to a form fully consistent with the Gaussian 3D function, which expresses an idealized distribution that meets the preferences of the polar water environment. The varied degrees of compatibility of the distribution observed with the idealized one allow the prediction of preferences to interactions with molecules of different polarity, including water molecules in particular. This paper analyzes a set of proteins with different levels of hydrophobicity distribution in the context of the solubility of a given protein and the possibility of complex formation.     

Facile Fabrication of Poly(vinyl alcohol)/Polyquaternium-10 (PVA/PQ-10) Anion Exchange Membrane with Semi-Interpenetrating Network

Anion exchange membranes (AEMs) are one of the core components of AEM fuel cells. A series of poly(vinyl alcohol)/polyquaternium-10 (PVA/PQ-10) AEMs with semi-interpenetrating networks (s-IPNs) are prepared by a simple solution-casting method using glutaraldehyde (GA) as a cross-linking agent. Subsequently, the prepared PVA/PQ-10 cross-linked membranes are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, mechanical analysis, water uptake and swelling ratio tests, ion exchange capacity (IEC) tests, ionic conductivity measurements, and oxidative/alkaline stability tests. The effects of the mass ratio of PVA and PQ-10 and the amount of cross-linking agent GA on the performance of the PVA/PQ-10 cross-linked membranes are systematically explored. The results show that the cross-linked PVA/PQ-10 AEMs have high IEC and low water uptake and swelling ratio, and its maximum ionic conductivity can reach 79.37 mS cm^–1 at 80 °C. In addition, the PVA/PQ-10 cross-linked membrane has good oxidative and alkaline stability under optimal preparation conditions. These results may provide valuable insights toward more effective scheme designs and new, simple preparation methods for AEMs with s-IPN structures.     

Countercurrent approach to the enrichment of Δ9c,11t-and Δ10t,12c-18:2 isomers by urea complexation

CLA refers to a group of geometrical and positional isomers of linoleic acid. CLA has been shown to have potentially beneficial effects on cancer, atherosclerosis, and body metabolism in animals. Mixtures containing equal amounts of these isomers are commonly used in many research studies because of their greater availability and lower cost relative to pure isomers. This has hindered progress in elucidating the biological properties of specific isomers and their relevance in animal and human biology. A method was developed that offers a compromise between cost and utility to make available enriched mixtures of either the Δ9c,11t- or Δ10t,12c-18:2 isomers for use in a wide range of experimental applications. A countercurrent approach was developed to separate the Δ9c,11t- and Δ10t,12c-18:2 isomers from an equal mixture of these two isomers by urea complexation. After three successive rounds of complexation using an equal amount of CLA and urea, a fraction enriched in Δ9c,11t-18:2 containing 42.5 and 17.4% of Δ9c,11t-and Δ10t,12c-18:2, respectively, was recovered. After a single round of complexation using 2.5 g urea/g CLA, a fraction enriched in Δ10t,12c-18:2 was recovered containing 29.7 and 69.1% of Δ9c,11t- and Δ10t,12c-18:2, respectively.