硫化零价铁去除水中污染物的效能及交互机制

如何同步提升零价铁去除水中污染物的反应速率和电子选择性已成为近年研究热点.基于无氧体系下硫化能通过抑制零价铁与水之间的副反应而改善体系还原除污染物效能,系统概括了不同硫化方式、硫化药剂和硫化程度合成的硫化零价铁理化特征,并揭示了其与硫化零价铁在不同水氧环境下去除不同污染物反应活性和电子选择性的交互机制.硫化能够主要通过...     

Molecular modeling study on inhibition performance of imidazolines for mild steel in CO2 corrosion

Corrosion inhibiting performance of 1-hydroxyethyl-2-heptadecylimidazoline (A) and 1-aminoethyl-2-heptadecylimidazoline (B) for mild steel was evaluated by combination of quantum chemistry calculation, molecular mechanics, and molecular dynamics simulation. The calculated results by quantum chemistry method demonstrated that frontier orbitals of A and B molecules are mainly located on imidazoline rings, and molecule B possesses higher reactivity than molecule A. The calculated results by molecular mechanics and molecular dynamics simulation presented that these two inhibitor molecules could form dense and high-coverage membranes to prevent diffusion of reactive corrosive species to metal surface. Furthermore, the adsorption energy, cohesive energy, and adsorption angle demonstrated that the binding affinity and stability of B membrane was remarkably greater than that of A, which indicated that B had better inhibition performance in CO₂ corrosion. The calculated results were well accorded with previous reported experimental results. These researches implied that molecular modeling might be an effective approach to assess inhibition performance, which has potential application in design of new inhibitors.     

Clickable inverse opal: a useful platform for fabrication of stimuli-responsive photonic materials

Based on azide-containing clickable inverse opal, a strategy for efficiently fabricating functional photonic materials was developed. By using three types of ethynylated compounds as model molecules, it is found that different functional groups can be facilely introduced into the prepared inverse opal via click reaction to access various inverse opaline materials.     

Cross-section measurements for the 58,60,61Ni(n,a)55,57,58Fe reactions at 8.50,9.50 and 10.50 MeV neutron energies

Cross sections of the 58,60,61Ni(n,α)55,57,58Fe reactions were measured at 8.50,9.50 and 10.50 MeV neut-ron energies based on the HI-13 tandem accelerator of Ch...     

球形破片侵彻下钢/铝复合靶板的失效模式与吸能机理

为研究复合靶板自身结构对其防护性能的影响，针对面密度相同的两层钢/铝、三层钢/铝/钢爆炸复合板以及均质钢板，采用系列弹道实验和LS-DYNA3D非线性有限元程序分析了复合靶板在球形破片侵彻作用下的失效模式和吸能机理，讨论了靶板层数、厚度和界面结合情况对失效模式的影响。研究结果表明:较其他因素而言，界面结合状态对靶板失效模式的影响最明显，当界面结合良好时，各层靶板均发生剪切冲塞破坏，而当结合界面发生拉伸失效时，较薄的背板以延性扩孔破坏为主；随着靶板总厚度的增大，靶板更易发生剪切冲塞破坏；当靶板的面密度和总厚度分别相等时，三层复合靶板的防护性能优于双层靶板。     

Transferrin recognition based on a protein imprinted material prepared by hierarchical imprinting technique

A novel kind of transferrin imprinted polymer particles was synthesized by a hierarchical strategy. First, transferrin was immobilized on silica beads by non-covalent absorption. Then, a pre-polymerization mixture, composed of 1,4-bis(acryloyl)piperazine, methacrylamide, methacrylic acid, ammonium sulfate and polyoxyethylene sorbitan monolaurate, was irrigated into the pores of silica particles, and polymerized at 25 °C. Finally, the silica matrix was etched with ammonium hydrogen fluoride, not only to remove the template protein, but also to expose protein recognition sites on the surface of the imprinted polymer. The binding capacity of the transferrin-imprinted particles is 6.3 mg of protein per gram of material, and the time required to reach adsorption equilibrium was less than 10 min. The imprinting factor of transferrin is ca. 3.3 in the presence of ribonuclease B, cytochrome c and β-lactoglobulin. The results indicate that these imprinted polymer particles can recognize transferrin with good selectivity, high binding capacity and fast mass transfer. They may be applied as an artificial antibody to remove the high abundance proteins in plasma.

Chemical constituents from Glehnia littoralis and their chemotaxonomic significance

Abstract

Phytochemical investigation of the roots of Glehnia littoralis Fr. Schmidt. ex Miq. led to the isolation of 16 known compounds, including three β-carboline alkaloids (1–3), four phenylpropanoids (4–7), five phenolic acids (8–12), three polyacetylenes (13–15) and one fatty acid (16). The structures of these compounds were elucidated on the basis of spectral analysis and comparison with those reported in literatures. To the best of knowledge, the report of the first β-carboline alkaloid in the Umbelliferae family. Additionally, compounds 1–5, 9, 10 and 16 have not been reported from any species in Umbelliferae family, compounds 7, 8 and 12 were isolated from the genus Glehnia for the first time and could be of the chemotaxinomic significance and serve as valuable chemotaxonomic makers for G. littoralis. The chemotaxonomic significance of the isolated compounds was summarised.     

Research on warehouse operation: A comprehensive review

An extensive review on warehouse operation planning problems is presented. The problems are classified according to the basic warehouse functions, i.e., receiving, storage, order picking, and shipping. The literature in each category is summarized with an emphasis on the characteristics of various decision support models and solution algorithms. The purpose is to provide a bridge between academic researchers and warehouse practitioners, explaining what planning models and methods are currently available for warehouse operations, and what are the future research opportunities.     

Direct electrochemistry and electrocatalysis of hemoglobin entrapped in semi-interpenetrating polymer network hydrogel based on polyacrylamide and chitosan

Semi-interpenetrating polymer network (semi-IPN) hydrogel based on polyacrylamide (PAM) and chitosan was prepared to immobilize redox protein hemoglobin (Hb). The Hb-PAM-chitosan hydrogel film obtained has been investigated by scanning electron microscopy (SEM) and UV-VIS spectroscopy. UV-VIS spectroscopy showed that Hb kept its secondary structure similar to its native state in the Hb-PAM-chitosan hydrogel film. Cyclic voltammogram of Hb-PAM-chitosan film-modified glass carbon (GC) electrode showed a pair of well-defined and quasi-reversible redox peaks for Hb Fe(III)/Fe(II), indicating that direct electron transfer between Hb and GC electrode occurred. The electron-transfer rate constant was about 5.51 s(-1) in pH 7.0 buffers, and the formal potential (E degrees ') was -0.324 V (vs. SCE). The dependence of E degrees ' on solution pH indicated that one-proton transfer was coupled to each electron transfer in the direct electron-transfer reaction. Additionally, Hb in the semi-IPN hydrogel film retained its bioactivity and showed excellent electrocatalytic activity toward H(2)O(2). The electrocatalytic current values were linear with increasing concentration of H(2)O(2) in a wide range of 5-420 microM. The unique semi-IPN hydrogel would have wide potential applications in direct electrochemistry, biosensors and biocatalysis.     

Simultaneous Spray Self‐Assembly of Highly Loaded ZIF‐8–PDMS Nanohybrid Membranes Exhibiting Exceptionally High Biobutanol‐Permselective Pervaporation

The ability to obtain a maximum loading of inorganic nanoparticles while maintaining uniform dispersion in the polymer is the key to the fabrication of mixed‐matrix membranes with high pervaporation performance in bioalcohol recovery from aqueous solution. Herein, we report the simultaneous spray self‐assembly of a zeolitic imidazolate framework (ZIF)–polymer suspension and a cross‐linker/catalyst solution as a method for the fabrication of a well‐dispersed ZIF‐8–PDMS nanohybrid membrane with an extremely high loading. The ZIF‐8–PDMS membrane showed excellent biobutanol‐permselective pervaporation performance. When the ZIF‐8 loading was increased to 40 wt %, the total flux and separation factor could reach 4846.2 g m⁻² h⁻¹ and 81.6, respectively, in the recovery of n‐butanol from 1.0 wt % aqueous solution (80 °C). This new method is expected to have serious implications for the preparation of defect‐free mixed‐matrix membranes for many applications.