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1.
The surface charge is a key concept in electrochemistry. Mathematically, the surface charge is obtained from a spatial integration of the volume charge along a particular direction. Ambiguities thus arise in choosing the starting and ending points of the integration. As for electrocatalytic interfaces, the presence of chemisorbates further complicates the situation. In this minireview, I adopt a definition of the surface charge within a continuum picture of the electric double layer. I will introduce surface charging behaviors of firstly ordinary electrochemical interfaces and then electrocatalytic interfaces featuring partially charged chemisorbates. Particularly, the origin of nonmonotonic surface charging behaviors of electrocatalytic interfaces is explained using a primitive model. Finally, a brief account of previous studies on the nonmonotonic surface charging behavior is presented, as a subline of the spectacular history of electric double layer.  相似文献   
2.
Carotenoids are an essential component of cashew and can be used in pharmaceuticals, cosmetics, natural pigment, food additives, among other applications. The present work focuses on optimizing and comparing conventional and ultrasound-assisted extraction methods. Every optimization step took place with a 1:1 (w:w) mixture of yellow and red cashew apples lyophilized and ground in a cryogenic mill. A Simplex-centroid design was applied for both methods, and the solvents acetone, methanol, ethanol, and petroleum ether were evaluated. After choosing the extractor solvent, a central composite design was applied to optimize the sample mass (59–201 mg) and extraction time (6–34 min). The optimum conditions for the extractor solvent were 38% acetone, 30% ethanol, and 32% petroleum ether for CE and a mixture of 44% acetone and 56% methanol for UAE. The best experimental conditions for UAE were a sonication time of 19 min and a sample mass of 153 mg, while the CE was 23 min and 136 mg. Comparing red and yellow cashews, red cashews showed a higher carotenoid content in both methodologies. The UAE methodology was ca. 21% faster, presented a more straightforward composition of extracting solution, showed an average yield of superior carotenoid content in all samples compared to CE. Therefore, UAE has demonstrated a simple, efficient, fast, low-cost adjustment methodology and a reliable alternative for other applications involving these bioactive compounds in the studied or similar matrix.  相似文献   
3.
We used a diamond anvil cell(DAC) to control the deformation of synthesized copper nanorods and silver nanoparticles. And we measured the surface plasmon resonance of copper nanorods and silver nanoparticles, which exhibit redshifts or blueshifts. The surface plasmon resonance shows an abnormal blue shift for both copper nanorods and silver nanoparticles. The solvents of copper nanorods and silver nanoparticles are n-hexane and water, where the pressure loads include quasi-hydrostatic and non-hydrostatic.  相似文献   
4.
This article reports a surface plasmon resonance (SPR) strategy capable of label-free yet amplified in situ immunoassays for sensitive and specific detection of human IgG (hIgG), a serum marker that is important for the diagnosis of certain diseases. Primarily, a wavelength-modulated Kretschman configuration SPR analyzer was constructed, and Au film SPR biosensor chips were fabricated. Specifically, based on Au nanoparticles (AuNPs) adsorbed on the surface of the Au film, the AuNP/Au film was coated with polydopamine (PDA) to fix streptavidin (SA), and then the biotinylated antibodies were connected to the surface of the biosensor chip. The SPR analyzer was utilized for in situ real-time monitoring of hIgG. Due to the immunological recognition between the receptor and target, the surface plasmon waves produced by the attenuated total reflection were affected by the changes in the surface of the biosensor chip. The resonance wavelength (λR) of the output spectra gradually redshifted, and the redshift degrees were directly related to the target concentration. The biosensor can realize the in situ detection of hIgG, displaying satisfactory sensitivity, excellent specificity and stability. Briefly, by monitoring the shift in λR after specific binding, a new SPR immunoassay can be customized for label-free, in situ and amplified hIgG detection. The operating principle of this research could be extended as a common protocol for many other targets of interest.  相似文献   
5.
在光电子学应用中,器件性能主要取决于半导体纳米材料中的光生载流子动力学过程. 但是,受反应速率、材料表面积、材料组成等多种因素影响,描述其中的动力学过程非常具有挑战性. 模拟光生载流子动力学过程可以通过绝热分子动力学方法实现,即求解包含非绝热耦合项的含时薛定谔方程. 在众多绝热分子动力学方法中,面跳跃方法出色地平衡了计算精度和计算成本,因而成为描述半导体纳米材料中不同非绝热过程间竞争的有力工具,已被用来模拟材料中的超快动力学过程和其他复杂效应,如Janus过渡金属二硫族化合物范德华异质结中的电荷分离. 本综述通过介绍该领域代表性的理论及实验工作,阐述了光生载流子对半导体纳米材料性能的重要影响,以及面跳跃方法在描述其动力学行为中的重要作用. 由于日趋复杂的材料体系对理论工作提出了巨大的挑战,本综述重点介绍了最近用于模拟这些复杂材料的一些开创性的新方法,包括高精度的电子结构方法和与之相结合的绝热分子动力学方法.  相似文献   
6.
Although driven by different research interests, single-site catalysts and single-atom catalysts are both believed to be model systems bridging homogeneous and heterogeneous catalysis. The two concepts are similar but different. In this review, we will first explain the difference between single-atom catalysis and single-site catalysis, in terms of their goals, synthetic methods and coordination structures of corresponding catalysts. Then, we will introduce the surface organometallic chemistry method, a method traditionally used for synthesizing single-site catalyst. We will explain why it might benefit the single-atom catalysis community. At last, the choice of support to accommodate the method for synthesizing single-atom catalysts will be discussed.  相似文献   
7.
We describe the structure and properties of the finite-dimensional symmetric algebras over an algebraically closed field K which are socle equivalent to the general weighted surface algebras of triangulated surfaces, investigated in [11]. In particular, we prove that all these algebras are tame periodic algebras of period 4. The main results of this paper form an essential step towards a classification of all symmetric tame periodic algebras of period 4.  相似文献   
8.
Removal of metal ions from water can not only alleviate the scaling problem of domestic and industrial water, but also solve the water safety problem caused by heavy metal ion pollution. Here, we fabricate a positively charged nanofiltration membrane via surfactant-assembly regulated interfacial polymerization(SARIP) of 2-methylpiperazine(MPIP) and trimesoyl chloride(TMC). Due to the existence of methyl substituent, MPIP has lower reactive activity than piperazine(PIP) but stronger affinity to hexane, resulting in a nanofiltration(NF) membrane with an opposite surface charge and a loose polyamide active layer. Interestingly, with the help of sodium dodecyl sulfate(SDS) assembly at the water/hexane, the reactivity between MPIP and TMC was obviously increased and caused in turn the formation of a positively charged polyamide active layer with a smaller pore size, as well as with a narrower pore size distribution. The resulting membrane shows a highly efficient removal of divalent cations from water, of which the rejections of MgCl2, CoCl2 and NiCl2 are higher than 98.8%, 98.0% and 98.0%, respectively, which are better than those of most of other positively charged NF membranes reported in literatures.  相似文献   
9.
Low-efficiency charge separation in metal sulfides is a major obstacle to realizing high photocatalytic performance. Herein, we propose the concept of a similar surface domain potential difference between adjacent microdomains with and without surface S vacancies on ZnIn2S4 to mediate charge separation. Defective ZnIn2S4 microspheres (DZISNPs) are prepared through a solvothermal method combined with a low-temperature hydrogenation surface engineering strategy. The as-prepared DZISNPs with a narrowed bandgap of 2.38 eV possess a large specific surface area of 178.5 m2 g?1, a pore size of 6.89 nm, and a pore volume of 0.36 cm3 g?1, which further improves the visible light absorption. The resultant DZISNPs exhibit excellent visible light activity (2.15 mmol h?1 g?1), which is ~two-fold higher than that of the original DZISNP. The experimental results and DFT calculations reveal that the enhanced property can be a result of the surface S vacancy-induced surface domain potential difference, promoting the spatial separation of electrons and holes. Furthermore, the long-term stability of the DZISNPs indicates that the formation of surface S vacancies can inhibit the photocorrosion of ZnIn2S4. This strategy provides new insights for fabricating highly efficient and stable sulfide photocatalysts.  相似文献   
10.
In this research, we investigated the synthesis of a novel water-soluble bis azo pyrazolin-5-one (ABP) which was synthesized efficiently via the regioselective reaction of hydrazine with coumarin hydrazone (CMH). Also, we evaluate their anti-corrosion and anti-bacterial behavior. The inhibition efficiency of ABP in an acidic medium (1.0 M HCl) was evaluated using various electrochemical and surface morphology measurements. The novel bis pyrazole-based azo dye ABP (16 × 10?6 M) demonstrated a higher protection capacity (93.3 %). Tafel curves revealed that ABP was a mixed-type inhibitor. The adsorption of ABP on the C-steel (CS) surface is proven by the alteration in (Rct and Cdl) impedance characteristics and obeyed the Langmuir isotherm model. SEM/EDX, AFM, and XPS surface examinations confirmed the enhancement of an adsorbed film protects the CS surface from acid corrosion at the appropriate dose. Furthermore, theoretical calculations using DFT and MC simulations were performed to identify the active sites on ABP molecules in charge of the adsorption and surface protection of the CS. The adsorption of bis pyrazole-based azo dye on the metal surface explained the protection mechanism. Moreover, the ABP screened for its antimicrobial activity against sulfate-reducing bacteria (SRB), and the calculated inhibition efficiency was 100 %. The current work presents significant results in manufacturing and producing novel water-soluble bis pyrazole-based azo dye derivative with high anti-corrosion and anti-microbial efficiency.  相似文献   
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