Photoactive Earth‐Abundant Iron Pyrite Catalysts for Electrocatalytic Nitrogen Reduction Reaction

The generation of ammonia, hydrogen production, and nitrogen purification are considered as energy intensive processes accompanied with large amounts of CO₂ emission. An electrochemical method assisted by photoenergy is widely utilized for the chemical energy conversion. In this work, earth‐abundant iron pyrite (FeS₂) nanocrystals grown on carbon fiber paper (FeS₂/CFP) are found to be an electrochemical and photoactive catalyst for nitrogen reduction reaction under ambient temperature and pressure. The electrochemical results reveal that FeS₂/CFP achieves a high Faradaic efficiency (FE) of ≈14.14% and NH₃ yield rate of ≈0.096 µg min^?1 at ?0.6 V versus RHE electrode in 0.25 m LiClO₄. During the electrochemical catalytic reaction, the crystal structure of FeS₂/CFP remains in the cubic pyrite phase, as analyzed by in situ X‐ray diffraction measurements. With near‐infrared laser irradiation (808 nm), the NH₃ yield rate of the FeS₂/CFP catalyst can be slightly improved to 0.1 µg min^?1 with high FE of 14.57%. Furthermore, density functional theory calculations demonstrate that the N₂ molecule has strong chemical adsorption energy on the iron atom of FeS₂. Overall, iron pyrite‐based materials have proven to be a potential electrocatalyst with photoactive behavior for ammonia production in practical applications.     

Highly refractive polyimides containing pyridine and sulfur units: synthesis and thermal,mechanical, solubility and optical properties

Two series of isomers containing pyridine and sulfur unit aromatic diamine monomers, 4,4′‐bis(5‐amino‐2‐pyridinylsulfanyl)diphenyl sulfide ( 2a ), 4,4′‐bis(6‐amino‐3‐pyridinylsulfanyl)diphenyl sulfide ( 2b ) and 4,4′‐bis(5‐amino‐6‐methyl‐2‐pyridinylsulfanyl)diphenyl sulfide ( 2c ), 4,4′‐bis(5‐amino‐4‐methyl‐2‐pyridinylsulfanyl)diphenyl sulfide ( 2d ), were designed and synthesized. Aimed at clarifying the structure–property relationships of pyridine‐ and sulfur‐containing high refractive polymers, 2a was polymerized with various dianhydrides to prepare polyimides PI ‐1?PI ‐7 and 2b , 2c , 2d were reacted with 4,4′‐[p ‐thiobis(phenylenesulfanyl)]diphthalic anhydride to prepare polyimides PI ‐8?PI ‐10. The polyimides showed excellent optical properties with average refractive indices ranging from 1.7006 to 1.7620 and birefringence as low as 0.0056. Meanwhile, comparative studies on their properties including solubility, thermal and mechanical, and optical transparency properties were performed. Some property differences of the isomers caused by the sequence changes were found. © 2017 Society of Chemical Industry     

Evaluation of maleic acid-based copolymers containing polyoxyethylene ether as inhibitors for CaCO3 scale

Polymer scale inhibitors have been widely used to reduce the loss caused by mineral scaling in circulating cooling water systems. In this article, four maleic acid-based copolymers [hydrolyzed polymaleic anhydride (HPMA)-AEO] containing different fatty alcohol polyoxyethylene ether (such as AEO-9, AEO-10, AEO-15, and AEO-20) are prepared by the way of free-radical copolymerization and characterized using Fourier transform infrared (FTIR), ¹H NMR, and gel permeation chromatographic (GPC) techniques. The effects of HPMA-AEO on CaCO₃ scale are studied in several aspects (such as dose, Ca²⁺ concentration, temperature, inhibition time, pH, the ratio of EO:carboxyl, and the relative supersaturation of CaCO₃ solution) by static experiments. The CaCO₃ scaling process with dosing of HPMA-AEO-9 is investigated under dynamic tests. CaCO₃ deposits and precipitate in the presence of HPMA-AEO-9 are analyzed using scanning electronic microscope (SEM) and X-ray diffraction (XRD). The results show that the performance of HPMA-AEO against CaCO₃ scale highly depends upon the ratio of EO:carboxyl; the introduction of AEO group can significantly improve the performance of HPMA-AEO to tolerate high alkalinity, high hardness, and high temperature; the presence of HPMA-AEO-9 can obviously affect the CaCO₃ scaling process on the tube wall through interfering with nucleation process and crystal growth process and significantly alter the surface morphology and crystal form of CaCO₃ deposits. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47470     

The study on the properties of TiCxN1−x coatings processed by cathodic arc physical vapour deposition

Titanium carbonitride (TiCN) is a popular hard coating for carbide cutting tools in various applications. The properties of TiCN are within its composition and can be controlled by maintaining the C–N ratio within the coating to a certain level. This paper studied the influence of carbon content and coating composition within TiC_xN_1?x coatings with regard to their mechanical properties. The substrate used was tungsten carbide (WC-6Co), which was prepared in-house through a powder metallurgy process, while the TiC_xN_1?x coatings were deposited in-house using cathodic arc physical vapour deposition (CAPVD). TiC_xN_1?x coatings improved the mechanical properties of carbide inserts. An increase in carbon content within TiC_xN_1?x coatings improved surface lubricity, reduced coefficient of friction, improved surface microhardness and increased Young's modulus, but reduced thermal conductivity of carbide inserts. The colour of TiC_xN_1?x coatings also changed with carbon content.     

一种应急管理信息系统在海油企业中的应用

本文主要介绍一套适合海油企业实际业务应用的应急管理信息系统,系统通过模块化、组件化模式实现灵活应用配置,并可根据用户实际应用需求进行模块组合、拆解,为不同领域的企业和厂区搭建适用的定制化应用系统,满足企业日常安全应急管理需求,为应急指挥工作提供辅助决策支持。     

Adhesion to pharyngeal epithelium and modulation of immune response: Lactobacillus salivarius AR809, a potential probiotic strain isolated from the human oral cavity

Microbiome modulators such as probiotics are known to modulate oral diseases. Very few probiotics are commercially available for use in the oral cavity. In this context, we selected human-origin Lactobacillus salivarius AR809 as a promising oropharyngeal probiotic and characterized its functional and immunomodulatory properties. Results demonstrated that AR809 could efficiently adhere to pharyngeal epithelial FaDu cells, antagonize Staphylococcus aureus, adapt to the oral environment, and modulate host innate immunity by inducing potentially protective effects. Particularly, AR809 diminished proinflammatory activity by enhancing the production of IL10 and inhibiting the expression of tumor necrosis factor-α, IL1B, inducible nitric oxide synthase, and RELA. Finally, we observed that AR809 grew efficiently when cultured in milk, suggesting that the preparation of a fermented milk product containing AR809 could be a practical way to administer this probiotic to humans. In conclusion, AR809 has high potential to adhere to the pharyngeal mucosa and could be applied in novel milk-based probiotic fermented food products.     

Pretreatment of piggery digestate wastewater by ferric-carbon micro-electrolysis under alkalescence condition

Due to the low COD/TN ratio, piggery digestate wastewater is non-biodegradable and pathogenic; its advanced treatment is becoming a wide-spread environmental concern. In this study, the process of Fe-C micro-electrolysis was applied to pretreat piggery digestate wastewater. Fe-C micro-electrolysis was confirmed effectively to enhance biodegradability of the piggery digestate wastewater. Response surface methodology (RSM) was employed to study the interactions between factors and optimize operating parameters. The optimum conditions for Fe-C micro-electrolysis were found to be 150 g/L of dosages of Fe-C particles, 6 L/h of aeration rate and 9 h of hydraulic retention time at pH 7.6, respectively. Under these conditions, the obtained chemical oxygen demand (COD) removal efficiency was 52.62%, and the ratio of BOD/COD increased from 0.13 to 0.285, which showed improvement of biochemical property. Furthermore, SEM analysis indicated the surface configuration of Fe-C particles. More important, this process could effectively pretreat the piggery digestate wastewater and avoid the generation of secondary pollution.