Structure Of NF Research Articles

Understanding of the synergy effect of DBD plasma discharge combined to photocatalysis in the case of Ethylbenzene removal: Interaction between plasma reactive species and catalyst

Hybrid non-thermal plasma combined with photocatalysis is an efficient technology for the degradation of volatile organic compounds (VOCs) and leads to a synergetic boosting effect of the degradation process. Herein, the degradation of ethylbenzene (EB) in a hybrid lab-scale reactor was performed. In the combined mode (plasma DBD and photocatalysis [TiO2 + UVA]), the degradation of EB was synergetically boosted, and a higher degradation efficiency was reached. In this study, the behavior of the synergetic effect was investigated whilst varying several operational conditions, including the UV light source (UVA and UVC), the TiO2 weight (7.5–22.51 g·m-²), the addition of metallic dopants to the TiO2 at different weight ratios (x%Cu-TiO2 and x%MnO2-TiO2, where x = 1, 3, 5 and 10 for the weight ratios of Cu:TiO2 and MnO2:TiO2) and the catalyst support (glass fiber tissue [GFT] and nickel foam [NF] with different thicknesses [0.3–3.3 mm]). Moreover, the oxygen content (0–100%) in the reactor atmosphere was examined. The results showed an enhancement of the synergetic effect under UVC (TiO2 + UVC + DBD), which may be a consequence of intensive ozone decomposition under UVC and the generation of reactive atomic oxygen. The improvement of the synergetic effect under 1% Cu-TiO2 and 10% MnO2-TiO2 catalysts is assumed to reflect the role of metallic species in the production of oxygen species on the TiO2 surface via the ozone depletion mechanism. Furthermore, TiO2/NF (3.3 mm) showed the highest synergetic effect, likely due to the conductive character and the 3D porous structure of NF. Finally, the rich oxygen composition had an apparent impact on the synergetic effect.

Design and preparation of 3D porous Ni–P/Ni integrated electrodes by electrodeposition for hydrogen evolution by electrolysis of water

Developing non-noble metal catalysts with low prices, high activity and strong stability plays a vital role in the storage and transformation of clean energy. In this study, the 3D porous structure of NF was modified in situ by electrodeposition. The electrochemical active area of Ni/NF porous structure was increased by 85.4% after 500 ​s electrodeposition. The structure, composition and morphology of the catalyst were studied by XRD, XPS, SEM, TEM and BET. In order to further improve the activity of HER, the surface of Ni–P/Ni/NF was hydrophilically treated with PSS-PPy. Compared with Ni–P/Ni/NF, the wetting angle of PSS-PPy/Ni–P/Ni/NF decreased by 32.3% from 53.6° to 79.2° and the overpotential decreased by 25.5% from 145 ​mV to 108 ​mV at the current density of 10 ​mA/cm2. PSS-PPy/Ni–P/Ni/NF also showed stable electrocatalytic activity. In a word, these findings have great prospects for the design and preparation of porous electrodes.

Stabilized cobalt-based nanofilm catalyst prepared using an ionic liquid/water interfacial process for hydrogen generation from sodium borohydride

The design and construction of transition metal catalysts with high performance and low-cost characteristics are imperative for liquid hydrogen storage materials. In this study, we prepared ultrathin carbon-stabilized Co-doped CoxOy nanofilms (C–Co/CoxOy NFs) using an ionic liquid/water interface strategy for sodium borohydride (NaBH4) hydrolysis. Owing to its two-dimensional (2D) NF structure and the protective effects of the composite carbon, the C–Co/CoxOy NF catalyst exhibited remarkable activity and durability for hydrogen generation from NaBH4 hydrolysis. The hydrogen generation rate reached 8055 mL·min−1·gCo−1 (5106 mL·min−1·gCat−1) and the catalyst could be recycled more than 20 times, surpassing most reported metal-based catalysts under comparable conditions. In addition, the exceptional 2D Co-based NF structures, with numerous active sites, assisted in the activation of NaBH4 and water molecules, promoting hydrogen production. Thus, these results provided an in-depth understanding of hydrogen generation from NaBH4 hydrolysis, and an effective strategy for rationally designing highly active and durable 2D NF catalysts.

Ternary metal sulfides MoCoNiS derived from metal organic frameworks for efficient oxygen evolution

Developing a highly active and low-cost non-precious metal electrocatalyst for oxygen evolution has been urgent for the clean energy system. Herein, the ternary metal sulfides MoCoNiS supported on nickel foam (MoCoNiS/NF) are successfully prepared using Mo doping Co-based metal-organic framework (Co-MOF) as precursor, which may be helpful for the good dispersion of different metal element. The uniform elements distribution of Mo, Co and Ni on MoCoNiS/NF is determined by all kinds of physical characterization. Mo doping may regulate the electronic environment around Co and Ni, suggesting the potential synergistic effects between different heteroatoms. Electrochemical test shows that MoCoNiS/NF exhibits the excellent OER activity than other single metal or binary metal sulfides as comparison samples, needing only 151 and 226 mV overpotential to achieve current density of 10 (η10 = 151 mV) and 100 mA cm−2 (η100 = 226 mV), respectively. The excellent stability of MoCoNiS/NF has been achieved. The remarkable OER performance of MoCoNiS/NF may due to the synergistic effects and good electrical conductivity as well as the three-dimensional structure of NF as substrate. Therefore, the rational design of MOF derived multi transition metal-based electrocatalysts will be an effective way for increasing OER performance.

Focus constructions, verb types and the SV/VS order in Italian: An acquisitional study from a syntax–prosody perspective

This paper investigates the realization of subjects in Broad and Narrow Focus constructions, from both an acquisitional and a theoretical perspective. Specifically, NF structures include Information (IF) and Corrective (CF) subjects and the study concerns Italian children (4–9 y.o.). Data are collected through an original experiment, based on spontaneous answers to (recorded) questions associated to scene settings. It is shown that the SV strategy is the most frequently used, independent of either Focus or verb type (considering transitive, unaccusative and unergartive verbs). Importantly, however, prosodic analysis shows that the SV order is systematically associated to distinct contours according to Focus types. As for the VS order, it appears as a late acquisition (around 7 y.o.) for both NF and BF constructions and is always associated with a downgrading contour. In a cartographic approach, these results lead to the conclusion that focus-related discourse and p-features are merged in dedicated projections and trigger movement to be valued and interpreted at Spell-Out. Consequently, p-features are uninterpretable at PF in the VS order. Finally, since the realization of postverbal subjects is part of the Null Subject Parameter, VS late emergence supports the hypothesis that the discourse-related competences connected with its acquisition are managed after 7 y.o.

How to fit a response current-concentration curve? A semi-empirical investigation of non-enzymatic glucose sensor based on PANI-modified nickel foam

Linear relationships between current response and glucose concentration have long been preferred in studying non-enzymatic glucose electrochemical sensors. The relationships, however, are usually not linear in a wide concentration range. Under given conditions, solution diffusion coefficient is an important factor leading to the nonlinearity. Herein we analyzed the effect of glucose concentration (c) on solution diffusion coefficient and proposed a new simple sensing current response (i) equation for expressing the relationship between i and c derived from the Cottrell formula and the diffusion coefficient formula. The semi-empirical equation enables the relationship to be represented accurately over a wide glucose concentration range instead of having to be divided into two or more linear segments. For verifying its applicability, we fabricated a non-enzyme glucose sensing electrode with polyaniline-modified nickel foam (PANI/NF) by oxidant-induced in situ polymerization. An i-c curve of the electrodes has been investigated and the simple semi-empirical equation can exactly match the measurement within a c range from 1.0μM to 20mM, the total mean squared error for glucose solution is 0.000. In addition, the experiments of sensitivity, limit of detection, reproducibility and stability in 0.1M NaOH all present satisfactory results, due to the 3D structure and plentiful surface active sites of NF, as well as the promotion of PANI for electrocatalytic glucose oxidation. Further, we prepared a PANI-hydroxyapatite-modified NF sensing electrode, and research results suggest that the semi-empirical equation is also appropriate for the three-component electrode system.

Highly sensitivity and homogeneous SERS platforms based on 3D-GNF/AgNPs hybrid structures

A three-dimensional surface enhanced Raman scattering (SERS) substrate based on graphene nanofoam (GNF)/AgNPs hybrid nanostructure has been prepared using a typical liquid phase reduction synthetic method. The synthesized materials which utilized the three-dimensional framework structure of NF with micropore diameter 50–500 μm were illustrated by scanning electron microscope (SEM) images. Meanwhile, the NF was coated with graphene oxide (GO) evidenced by energy dispersive spectra (EDS) images. In addition, the composite was modified with Ag nanoparticles (AgNPs) whose average size was about 500 nm. The preparation process is very economic and environmental-friendly. The SERS experiment of hybrid nanostructure substrate using Rhodamine 6 G (R6G) as probe molecules showed that the concentration of GO aqueous solution and the Ag NPs growth time were two key factors to determine the intensity of SERS signal and the limit of detection of the hybrid nanostructure is as low as 1 × 10−8 M. 30 different test areas were selected to evaluated the homogeneous SERS platforms, and the RSD is only 8.2%, indicating highly uniformed and reproducibility. In summary, the three-dimensional (3D) substrates by a simple method showed a good sensitivity, stability and reproducibility, and it is promising for application in the field of rapid trace molecule detection in the realistic environment.

Semiconductor-Metal Nanofloret Hybrid Structures by Self-Processing Synthesis.

We present a synthetic strategy that takes advantage of the inherent asymmetry exhibited by semiconductor nanowires prepared by Au-catalyzed chemical vapor deposition (CVD). The metal-semiconductor junction is used for activating etch, deposition, and modification steps localized to the tip area using a wet-chemistry approach. The hybrid nanostructures obtained for the coinage metals Cu, Ag, and Au resemble the morphology of grass flowers, termed here Nanofloret hybrid nanostructures consisting of a high aspect ratio SiGe nanowire (NW) with a metallic nanoshell cap. The synthetic method is used to prepare hybrid nanostructures in one step by triggering a programmable cascade of events that is autonomously executed, termed self-processing synthesis. The synthesis progression was monitored by ex situ transmission electron microscopy (TEM), in situ scanning transmission electron microscopy (STEM) and inductively coupled plasma mass spectrometry (ICP-MS) analyses to study the mechanistic reaction details of the various processes taking place during the synthesis. Our results indicate that the synthesis involves distinct processing steps including localized oxide etch, metal deposition, and process termination. Control over the deposition and etching processes is demonstrated by several parameters: (i) etchant concentration (water), (ii) SiGe alloy composition, (iii) reducing agent, (iv) metal redox potential, and (v) addition of surfactants for controlling the deposited metal grain size. The NF structures exhibit broad plasmonic absorption that is utilized for demonstrating surface-enhanced Raman scattering (SERS) of thiophenol monolayer. The new type of nanostructures feature a metallic nanoshell directly coupled to the crystalline semiconductor NW showing broad plasmonic absorption.

Proximity effect in multilayer structures with alternating ferromagnetic and normal layers

The character of the penetration of superconducting correlations into multilayer FF…F, FNFN…FN, and NFNF…NF structures being in contact with a superconductor with the singlet pairing potential has been studied theoretically. Analytical expressions for the effective superconductivity penetration depth in such structures have been obtained in the limit of small layer thicknesses. Numerical calculations taking into account self-consistently the suppression of the superconductivity in the superconductor owing to the proximity effect have been performed at arbitrary thicknesses. A simple analytical dependence approximating the spatial variation of the Green’s function in a multilayer has been proposed. It has been shown that superconductivity is induced by the generation of two channels existing in parallel, one of which is characterized by the smooth (as in SN sandwiches) decay of the superconductivity, while damped oscillations (as in SF structures) take place in the second one.

Isolation and Characterization of Nicotiflorin Obtained by Enzymatic Hydrolysis of Two Precursors in Tea Seed Extract

Two flavonol triglycosides, camelliaside A (CamA) and camelliaside B (CamB), of tea seed extract (TSE) were subjected to enzymatic hydrolysis. Among five kinds of glycosidases investigated, beta-galactosidase (Gal) induced selective hydrolysis of CamA. On the other hand, pectinase (Pec) and cellulase (Cel) induced hydrolysis of CamB. For Gal and Pec, only kaempferol diglycoside (nicotiflorin, NF) was produced; on the other hand, significant amounts of kaempferol monoglycoside (astragalin, AS) and kaempferol (KR) were also detected for Cel. The combination of the use of Gal and Pec in the enzymatic hydrolysis of TSE afforded NF with high specificity. Crude NF with 22% purity was recovered from the enzymatic reaction mixture by extraction with organic solvent, and pure NF with >95% purity was obtained by crystallized in water. The chemical structure of NF was confirmed by (1)H and (13)C NMR analyses.

Conditional NF-L Transgene Expression in Mice forIn VivoAnalysis of Turnover and Transport Rate of Neurofilaments

We generated mice with doxycycline control of a human neurofilament light (NF-L) transgene in the context of the absence (tTA;hNF-L;NF-L(-/-)) or presence (tTA;hNF-L;NF-L(+/-)) of endogenous mouse NF-L proteins. Doxycycline treatment caused the rapid disappearance of human NF-L (hNF-L) mRNA in tTA;hNF-L mice, but the hNF-L proteins remained with a half-life of 3 weeks in the brain. In the sciatic nerve, the disappearance of hNF-L proteins after doxycycline treatment occurred in synchrony along the sciatic nerve, suggesting a proteolysis of NF proteins along the entire axon. The presence of permanent NF network in tTA;hNF-L;NF-L(+/-) mice further stabilized and extended longevity of hNF-L proteins by several months. Surprisingly, after cessation of doxycycline treatment, there was no evidence of leading front of newly synthesized hNF-L proteins migrating into sciatic nerve axons devoid of NF structures. The hNF-L proteins detected at weekly intervals reappeared and accumulated in synchrony at similar rate along nerve segments, a phenomenon consistent with a fast hNF-L transport into axons. We estimated the hNF-L transport rate to be of approximately 10 mm/d in axons devoid of NF structures based on the use of an adenovirus encoding tet-responsive transcriptional activator to transactivate the hNF-L transgene in hypoglossal motor neurons. These results provide in vivo evidence that the stationary NF network in axons is a key determinant of half-life and transport rate of NF proteins.

The processing strategy for the NF 2 relational frc-interface

The idea of the frc- (form-relations-conditions) interface is to reduce the user effort in the NF 2 (Non-First-Normal-Form) relational query formulation considerably. In the frc-interface the user only describes the structure of the result NF 2 relation in a straightforward and intuitive way without specifying how the result NF 2 relation is derived from the source NF 2 relations. The lack of explicit restructuring expressions from the frc-interface means that query processing must be based on a different approach than that used in query languages (e.g. the SQL extensions made for the NF 2 relational model) in which the user specifies the needed restructuring among data explicitly. In this paper we introduce our query processing strategy of the frc-interface which has been implemented in Prolog. Its kernel is a calculus consisting of two constructors (for concatenation and relation construction of NF 2 objects). By applying these constructors recursively to atomic-valued attribute representations, any NF 2 relation can be constructed. Our calculus-based approach affords the possibility of performing several operations at the same time, which gives a good starting point for efficient implementation. In the paper the optimization process used to manipulate several NF 2 relations is described.

Electronic structure of the radicals NF and NCl. III. The radiative lifetimes of the b 1Σ + and a 1Δ states

The radiative lifetimes of the b 1Σ + and a 1Δ states have been evaluated by perturbation expansions including X 3Σ −, a 1Δ, b 1Σ +, 1 3,1Π, 2 3,1Π, 2 3Σ − and 2 1Σ + states. All wavefunctions result from large MRD CI calculations. The b—X transition is dominated by the parallel transition moment; it is found to be much stronger than the a—X transition. The calculated radiative lifetimes of τ( 1Σ +)=18 ms, τ( 1Δ)=2.2 s for NF and τ( 1Σ +)=2.5–3.5 ms for NCl are in good accord with corresponding experimentally deduced values. The lifetime for the a 1Δ state in NCl is found to be τ( 1Δ)=1.1 s, ie. much longer than derived from a recent experiment. Its magnitude is consistent with the τ(b 1Σ +)/τ(a 1Δ) ratio of similar systems and with the decrease in lifetime from NF to NCl and is thus believed to be quite reliable. A detailed analysis of all contributions of the perturber states to the transition mechanism is made and comparison with the related data in SO, O 2 and S 2 is undertaken. The b-a transition probability dominated by the quadrupole transition is fairly constant in all the systems in the order of A = 0.013 (NF) - 0.0013 (S 2) s −1.

Electronic structure of the radicals NF and NCI. II. Potential energy curves for NCI

Large-scale MRD CI calculations are employed to determine the potential energy curves for the three lowest X 3Σ −, a 1Δ and b 1Σ + states of NCl with π *2 configuration, for the higher states arising from σ → π *, π → σ * and π → π* excitation and for the 2Π ion. Numerous avoided crossings are found to occur between curves in the region of internuclear separations treated. A comparison with the corresponding curves for the radicals NF, O 2 and SO is undertaken and the basic similarities and distinctions are discussed. The curves in NF and NCl are quite similar, with generally lower energy gaps in the second-row radical; they can to a large extent be constructed from the homonuclear counterpart by mixing of g and u symmetry and by taking into account the different multiplicities in the dissociation products N + Cl or F and O + O or S.

Electronic structure of the radicals NF and NCI. I. Potential energy curves for NF

Abstract Large-scale MRD CI calculations are employed to determine the potential energy curves for the three lowest X 3 Σ − , a 1 Δ and b 1 Σ + states of NCl with π *2 configuration, for the higher states arising from σ → π * , π → σ * and π → π* excitation and for the 2 Π ion. Numerous avoided crossings are found to occur between curves in the region of internuclear separations treated. A comparison with the corresponding curves for the radicals NF, O 2 and SO is undertaken and the basic similarities and distinctions are discussed. The curves in NF and NCl are quite similar, with generally lower energy gaps in the second-row radical; they can to a large extent be constructed from the homonuclear counterpart by mixing of g and u symmetry and by taking into account the different multiplicities in the dissociation products N + Cl or F and O + O or S.