氧吸附对CdS—CdSe烧结膜电导性能的影响

CdS—CdSe烧结膜具有显著的光敏特性。氧气在这种多晶薄膜上的吸附提高了薄膜中晶粒间的界现势垒,并改变了晶粒中的载流子浓度.表现在薄膜的电导率和电子迁移率随着氧气的吸附而下降.这种薄膜在空气中,50℃下经过30min的退火处理,晶粒间的界面势垒可提高约14meV,薄膜在氮气中的退火处理使界面势垒有所下降。     

Highly selective thiocyanate electrode based on bis-[N-(2-hydroxyethyl)salicylaldimino]copper(II) complex as a neutral carrier.

A novel selective thiocyanate electrode of a PVC membrane based on bis-[N-(2-hydroxyethyl)salicylaldimino]copper(II) [Cu(II)-BNSDM] as a neutral carrier is reported. The selectivity sequence of this electrode is as follows: SCN- > ClO4- > I- > Sal- > Br- > NO2- > Cl- > NO3- > H2PO4- > SO4(2-), which is an anti-Hofmeister selectivity sequence. The electrode exhibits a Nernstian potential linear range to thiocyanate from 1.0 x 10(-1) to 6.0 x 10(-6) mol/L with a detection limit of 2.0 x 10(-6) mol/L and a slope of (-59.0+/-0.2)mV/decade in pH 5.0 of a phosphate buffer solution at 25 degrees C. Electrochemical impedance spectroscopy (EIS) and UV spectroscopy techniques were performed to understand the response mechanism of the electrode. The electrode had the advantage of simplicity, high selectivity, fast response and low detection limit compared with the other electrode, which had been reported before. The electrode had been applied to wastewater analysis, and the obtained results were satisfactory.     

阴极限制型Li／SOCl2电池过放电产物的热分析

Li/SOCl_2电池体系以其高比能量和优异的放电性能引起了电源界的重视。有关该体系的不安全行为曾有一些研究。本文用DSC、EDAX、XPS等方法分析了电池的反应产物和热敏性,和模拟组分对比,以图找出引起电池热失控爆炸的原因。     

The Functionality of Surface Hydroxy Groups on the Selectivity and Activity of Carbon Dioxide Reduction over Cuprous Oxide in Aqueous Solutions

Carbon dioxide (CO₂) reduction in aqueous solutions is an attractive strategy for carbon capture and utilization. Cuprous oxide (Cu₂O) is a promising catalyst for CO₂ reduction as it can convert CO₂ into valuable hydrocarbons and suppress the side hydrogen evolution reaction (HER). However, the nature of the active sites in Cu₂O remains under debate because of the complex surface structure of Cu₂O under reducing conditions, leading to limited guidance in designing improved Cu₂O catalysts. This paper describes the functionality of surface‐bonded hydroxy groups on partially reduced Cu₂O(111) for the CO₂ reduction reaction (CO₂RR) by combined density functional theory (DFT) calculations and experimental studies. We find that the surface hydroxy groups play a crucial role in the CO₂RR and HER, and a moderate coverage of hydroxy groups is optimal for promotion of the CO₂RR and suppression of the HER simultaneously. Electronic structure analysis indicates that the charge transfer from hydroxy groups to coordination‐unsaturated Cu (Cu_CUS) sites stabilizes surface‐adsorbed COOH*, which is a key intermediate during the CO₂RR. Moreover, the CO₂RR was evaluated over Cu₂O octahedral catalysts with {111} facets and different surface coverages of hydroxy groups, which demonstrates that Cu₂O octahedra with moderate coverage of hydroxy groups can indeed enhance the CO₂RR and suppress the HER.     

碳化钨催化剂电化学稳定性的研究

碳化钨(WC)催化剂在酸性体系中具有“类铂”的催化活性,且不被任何浓度的一氧化碳和几个ppm的硫化氢中毒,可以用于酸性燃料电池中的氢电极和电解合成中的活性阴极材料,也适作加氢和脱氢中的异相催化剂。作为电极材料碳化钨的电化学稳定性直接影响它的使用,但这方面的研究至今尚不多见。本文用恒电流阳极充电法研究WC粉末在酸性和碱性电解液中的电化学稳定性。     

Theoretical study on the reaction mechanism and thermodynamics of tin oxidation by oxygen species and chlorine species

In this work ab initio molecular orbital methods were employed to study the coal combustion reaction mechanisms of tin oxidized by different oxidants, including HOCl, HCl, ClO, ClO₂, NO₃, CO₂, and O₂. Eleven reaction pathways were identified. The results show that Sn can react with HCl, ClOO, CO₂, O₂, and NO₃ to form SnO and SnCl. SnO can be oxidized into SnCl by HOCl and HCl. SnCl can be further oxidized into a soluble compound, SnCl₂. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Studies on beta-type reaction and kinetics of lanthanides with p-bromochloroarsenazo

The reaction behaviour of the β-type chelates of lanthanide ions (Ln³⁺) with p-bromochloroarsenazo (4-CAsA-pB) in 0.01 mol l⁻¹ HClO₄ solution has been studied systematically by a spectrophotometric method. All the lanthanide ions can form β-type chelates with p-bromochloroarsenazo. The maximum absorption wavelength is in the range 727–731 nm, the molar absorptivities are about 6.0 × 10⁴ – 9.0 × 10⁴ cm² mol⁻¹, the composition ratio of Ln³⁺ ions with 4-CAsA-pB is 1:2 and the actual combining ratio is 2:4. The optimum acidity range (ΔpH value) of the formation of β-type chelates has been obtained. Kinetic parameters, such as the reaction order and rate constants, have also been studied and a formation mechanism for the β-type chelates has been proposed.     

热塑性淀粉力学性能的提升途径及作用机理

以可再生资源(如淀粉、纤维素和蛋白质等)为基础发展而来的生物可降解塑料受到人们越来越多的关注,是可降解塑料行业发展的重要方向之一。天然淀粉由于来源广、低成本和可生物降解的特点,广泛用于制备淀粉塑料,并用于农业、食品、医药和包装等行业,有望取代石油基衍生聚合物。淀粉大分子具有结晶结构,所含大量羟基可形成较强的分子间和分子内氢键,使其不能热塑加工,而当加入增塑剂后可破坏其结晶结构,从而用于制备热塑性淀粉。目前,热塑性淀粉的力学性能差,是影响其使用性能的首要问题。近年来国内外开展了大量的研究以试图增强其力学性能。本文主要以不同类型的热塑性淀粉为基础,以淀粉自身改性和外加组分改性两种提高其力学性能的途径为主线,以其力学性能的提升方法和作用机理为重点,系统总结了近年来国内外以提高热塑性淀粉材料的力学性能为目的的研究工作,归纳了影响力学性能的相关因素以及提升途径,并对该领域重点研究的内容进行了总结和展望。     

Rapid deswelling of sodium alginate/poly(N-isopropylacrylamide) semi-interpenetrating polymer network hydrogels in response to temperature and pH changes

In this study, temperature-/pH-responsive semi-interpenetrating polymer network (semi-IPN) hydrogels based on linear sodium alginate (SA) and cross-linked poly(N-isopropylacrylamide) (PNIPAAm) were prepared. The semi-IPN hydrogels reached an equilibrium deswelling state within 6 h in response to temperature or pH stimuli. Compared with the conventional PNIPAAm hydrogel, their dewelling rate in response to temperature was improved significantly, owing to the formation of a porous structure within the hydrogels in the presence of ionized SA during the polymerization process. Moreover, the deswelling process could be well described with a first-order kinetics equation and it is possible to design any hydrogel with the desired deswelling behavior through the control of the SA content in the semi-IPN hydrogels.     

Polyethylene glycol increases purification and recovery, alters retention behavior in flow-through chromatography of hemoglobin

Flow-through chromatography was a method for purification of hemoglobin (Hb) from red cell lysate. The presence of 0-5% polyethylene glycol (PEG) increased the retention time of Hb peak from 15 min to 20 min in flow-through ion-exchange chromatography (IEC) but decreased the retention time from 88 min to 62 min in the hydrophobic interaction chromatography (HIC). However, the purification and the recovery were both increased. For IEC the recovery of hemoglobin increased from 75% to more than 90%, and the purified Hb showed single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and one peak in size-exclusion HPLC. For HIC, the recovery of hemoglobin was improved significantly from 20% to 85% and the removal of lipids was 100%. The bioactivity of hemoglobin was well preserved in these two chromatographic processes. The mechanism for the effect of PEG in these two flow-through chromatographic processes was discussed.