pinecone/core-2020-05-10-deduplication huggingface dataset:
Film quality and electronic properties of a surface-anchored metal-organic framework revealed by using a multi-technique approach

V.M. acknowledges the EU for the funding through the granting of a Marie Curie Intra-European Fellowship (FP7-PEOPLE-2011; MOLSURMOF-301110). J.L. acknowledges the program of China Scholarship Council (CSC) for financial support. V.M., J.L., and C.W. acknowledge A. Terfort for supplying the thiol derivatives. M.P. and C.O. acknowledge financial support from the Spanish Government through grant projects MAT2013–47869-C4–1-P and SEV-2015–0496, and Generalitat de Catalunya through grant project 2014 SGR 501.The virtually unlimited versatility and unparalleled level of control in the design of metal-organic frameworks (MOFs) has recently been shown to also entail a potential for applications based on the electrical and electronic properties of this rich class of materials. At present, methods to provide reliable and reproducible contacts to MOF materials are scarce; therefore, we have carried out a detailed, multi-technique investigation of an empty and loaded prototype MOF, HKUST-1. Epitaxial thin films of this material grown on a substrate by using liquid-phase epitaxy have been studied by cyclic voltammetry, atomic force microscopy, and quartz crystal microbalance and their quality assessed. By using an ionic liquid as the electrolyte, it is shown that redox-active molecules like ferrocene can be embedded in the pores, enabling a change in the overall conductivity of the framework and the study of the redox chemistry of guest molecules inside the MOF.PostprintPeer reviewe
Residual porosity of 3D-LAM-printed stainless-steel electrodes allows galvanic exchange platinisation

Stainless-steel rods were manufactured by laser additive manufacturing (LAM or "3D-printing") from a stainless-steel (316L) powder precursor, and then investigated and compared to conventional stainless steel in electrochemical experiments. The LAM method used in this study was based on "powder bed fusion", in which particles with an average diameter of 20-40μm are fused to give stainless-steel rods of 3mm diameter. In contrast to conventional bulk stainless-steel (316L) electrodes, for 3D-printed electrodes, small crevices in the surface provide residual porosity. Voltammetric features observed for the 3D-printed electrodes immersed in aqueous phosphate buffer are consistent with those for conventional bulk stainless steel (316L). Two chemically reversible surface processes were observed and tentatively attributed to Fe(II/III) phosphate and Cr(II/III) phosphate. Galvanic exchange is shown to allow improved platinum growth/adhesion onto the slightly porous 3D-printed stainless-steel surface, resulting in a mechanically robust and highly active porous platinum deposit with good catalytic activity toward methanol oxidation
Synchrotron X ray tomographic study of a silicon electrode before and after discharge and the effect of cavities on particle fracturing

Silicon  Si  is proposed to be one of the most promising anode materials for next generation lithium ion batteries, but unsatisfactory discharge capacity and inevitable performance deterioration prevent their commercialisation. In amp; 8197;situ synchrotron X ray tomography is applied to a Si composite electrode based battery in its pristine and first discharged state and the degradation of the electron  and or ion conducting network, as well as degradation of Si particles, is quantitatively investigated. Thus, this study is complementary to previous X ray tomographic studies focusing on Si particles only. On the electrode level, the Si particles located in the central part of the electrode primarily experience crack formation; on the particle level, lithiation behaviour is heterogeneous and cavities are formed during electrode preparation and battery operation. The correlation between the electrochemical activities of Si particles and their individual contact with the conducting network is investigated and quantified  Si particles will experience lithiation only under the condition that at least 40 amp; 8201;  of their surface is electrically and ionically connecte
Mechanistic Insights into the Oxygen Reduction Reactionon Metal–N–C Electrocatalysts under Fuel Cell Conditions

Three different transition metal-C-N catalysts are tested under a range of fuel cell conditions. It is found that common features of the polarisation curve can be explained by a change in electrocatalytic mechanism. Utilising a simple model to quantify the change in mechanisms, iR free results of the fuel cell experiments are fit and found to be represented by a common set of parameters. The change in mechanism is assumed to be a switch from four electron reduction of oxygen to water to a two electron reduction to hydrogen peroxide followed by disproportionation of the hydrogen peroxide to water and oxygen. The data is used to estimate a mass specific exchange current density towards the ORR in the range 10-11-10-13 A g-1 depending on the catalyst. For the reduction of oxygen to hydrogen peroxide, the mass specific exchange current density is estimated to be in the range 10-2-10-3 A g-1. Utilising the electrokinetic model, it is shown how the mass transport losses can be extracted from the polarisation curve. For all three catalyst layers studied, these mass transport losses reach about 100mV at a current density of 1 A cm-2. Finally a discussion of the performance and site density requirements of the non-precious metal catalysts are provided, and it is estimated that the activity towards the ORR needs to be increased by an order of magnitude, and the site density by two/three orders of magnitude in order to compete with platinum as an ORR electrocatalyst
Role of carbonaceous fragments on the functionalization and electrochemistry of carbon materials

Carbonaceous fragments (CF) formed by acid treatment of carbon materials have important properties that are not completely understood. In this work, CF were produced by oxidation of CNT by using mineral acid followed by treatment with NaOH. The role of CF on CNT voltammetric properties was studied by using different materials: oxidized CNT (a-CNT), a-CNT refluxed in NaOH and neutralized with HCl (b-CNT), pristine CNT exposed to a CF suspension (c-CNT), and b-CNT exposed to a CF suspension (r-CNT). The extension of functionalization of these materials was evaluated by thermogravimetric analysis (TGA). The spectroscopic characterization (UV/Vis, fluorescence, FTIR, Raman and NMR) of CF indicates the presence of graphene-type conjugated aromatic rings with highly oxidized moieties. In this work we demonstrate that CF are responsible for the ameliorated voltammetric properties of oxidized CNT. Adsorption of CF on oxidized and non-oxidized CNT showed that CF provide active sites for hydroquinone (HQ) adsorption, enhancing current responses. The interaction of CF with carbon materials depended on both the surface oxidation degree and the surface roughness. Voltammograms from CF adsorbed on oxidized CNT indicate the presence of labile supramolecular structures with a voltammetric response typical of quinoid units. Carbon materials functionalized with CF displayed lower peak potentials and higher currents (30 to 180%) than the unmodified electrodes, demonstrating that CF is a promising material for sensors design.Thanks are due to FCT and COMPETE-QREN-EU for financial support: project PEst-/QUI/UI0686/2013 (Research Centre CQ/UM) and project PEst-C/CTM/ LA0025/2013 (IPC/I3N). RG and EC thank the FCT, POCH, and ESF for his Post- Doc (SFRH/BPD/86690/2012) and her Ph.D. grant (SFRH/BD/87214/2012), respectively.info:eu-repo/semantics/publishedVersio
Reagentless electrochemiluminescence from a nanoparticulate polymer of intrinsic microporosity (PIM-1) immobilized onto tin-doped indium oxide

In contrast to most common electrochemiluminescence (ECL) techniques that require either an additional reagent or continuous pulsing between oxidative and reductive potentials, here a fluorescent polymer of intrinsic microporosity (PIM-1) is shown to exhibit intrinsic ECL without the need for a co-reactant at positive applied potentials and as a function of pH. PIM-1 is known to possess high microporosity (based on its rigid and contorted molecular structure) and excellent fluorescence properties. By depositing a nanoparticulate form of the PIM-1 material onto tin-doped indium oxide, we achieve a hierarchically porous deposit with good sustained ECL activity in aqueous media. The mechanism for this reagentless ECL is suggested to be linked to reactive oxygen species produced at positive potentials and discussed in terms of potential analytical applications
Direct and rapid electrochemical detection of Pseudomonas aeruginosa quorum signaling molecules in bacterial cultures and cystic fibrosis sputum samples through cationic surfactant-assisted membrane disruption

Rapid detection of pathogenic bacteria present in patient samples is of utmost importance for the clinical management of bacterial-induced diseases. Herein, we describe an efficient and direct electrochemical approach for the detection of 2-heptyl-3-hydroxy-4-quinolone (PQS), 2-heptyl-4-hydroxyquinoline (HHQ), and pyocyanin (PYO) as a molecular signature of Pseudomonas aeruginosa (PA), a frequently infecting pathogen with high antibiotic resistance. The cationic surfactant hexadecyltrimethylammonium bromide (CTAB) enhances the effectiveness of an unmodified thin-film boron-doped diamond (BDD) electrode for the direct detection of PYO, HHQ, and PQS in bacterial cultures of PAO1 and PA14. Differential pulse voltammetry (DPV) is then used to monitor the production of these microbial metabolites in bacterial cultures of PAO1 over 10 h without any sample pretreatment. A proposed mechanism for the interaction of CTAB with bacteria cells is examined by zeta (ζ) potential measurements. Furthermore, the detection method is successfully extended to a clinical fluid matrix and applied to PA spiked cystic fibrosis (CF) sputum samples
Tailoring asymmetric discharge-charge rates and capacity limits to extend Li-O2 battery cycle life

Widespread issues with the fundamental operation and stability of Li-O2 cells impact cycle life and efficiency. While the community continues to research ways of mitigating side reactions and improving stability to realize Li-O2 battery prospects, we show that limiting the depth-of-discharge while unbalancing discharge/charge rate symmetry can extend Li-O2 battery cycle life by ensuring efficient reversible Li2O2 formation, markedly improving cycle life. Systematic variation of the discharge/charge currents shows that clogging from discharging the Li-O2 cell at high current (250 μA) can be somewhat negated by recharging with a lower applied current (50 μA), with a marked improvement in cycle life achievable. Our measurements determined that specific reduction of the depth of discharge in decrements from equivalent capacities of 1000 mAhg-1 to 50 mAhg-1 under symmetric discharge/charge currents of 50 μA strongly affected the cumulative discharge capacity of each cell. A maximum cumulative discharge capacity was found to occur at ~10 % depth of discharge (500 mAhg-1) and the cumulative discharge capacity of 39,500 mAhg-1 was significantly greater than cells operated at higher and lower depths of discharge. The results emphasize the importance of appropriate discharge/charge rate and depth of discharge selection for other cathode/electrolyte combinations for directly improving cycle life performances of Li-O2 batteries
In-situ thermal battery discharge using NiS2 as a cathode material

We thank AWE and the EPSRC (EP/K015540/1) for funding. JTSI acknowledges a Royal Society Wolfson Research Merit award. The research data supporting this publication can be accessed at https://doi.org/10.17630/92155136-9404-4844-a958-5de1e1af2c66NiS2 is a cathode material found in primary batteries which operate at high temperature. Herein we report the in situ battery discharge study of a thermal battery cell which uses NiS2 as a cathode, using simultaneous collection of powder neutron diffraction data and electrochemical data. Five different regions were observed upon battery discharge and the evolution of nickel sulfide phases has been studied. Four different nickel-containing phases are observed during discharge (NiS2, NiS, Ni3S2 and Ni). A new discharge mechanism has been proposed which does not include Ni7S6. Multiphase quantitative Rietveld refinement has allowed the percentages of the phases to be monitored during discharge. High intensity synchrotron powder X-ray diffraction has been used to study the resulting phases present in the cathode after battery discharge.Publisher PDFPeer reviewe
V2O3 polycrystalline nanorod cathode materials for Li-Ion batteries with long cycle life and high capacity retention

We report on the electrochemical performance of V2O3 polycrystalline nanorods (poly-NRs) as a cathode material for Li-ion batteries. Poly-NRs are formed through the thermal treatment of V2O5 nanotubes in a N2 atmosphere. X-ray and electron diffraction techniques are used to confirm the thermal reduction. Through galvanostatic cycling, we demonstrate that poly-NRs offer excellent capacity retention over 750 cycles. The capacity retention from the 50th to the 750th cycle was an impressive 94 %, retaining a capacity of approximately 120 mAh g−1 after 750 cycles. The outstanding stability of the nanocrystal-containing V2O3 poly-NRs over many cycles demonstrates that vanadium(III) oxide (V2O3) performs very well as a cathode material. Full Li-ion cells with paired a V2O3 poly-NR cathode and a pre-charged Co3O4 inverse opal (IO) conversion mode anode demonstrated high initial capacities and retained a capacity of 153 mAh g−1 after 50 cycles. The capacities achieved with our V2O3 poly-NRs/Co3O4 IO full cells are comparable to the capacities obtained from the most commonly used cathode materials when cycled in a half-cell arrangement versus pure Li metal
Confining Nanopore Bipolar Electrochemical Processes to Give Pattern in Space and Time

"Wireless" metal-coated nanopore electrode processes have been developed by Long and co-workers (R. Gao, Y. Lin, Y.-L. Ying, X.-Y. Liu, X. Shi, Y.-X. Hu, Y.-T. Long, Small, 2017 DOI: 10.1002/smll.201700234), confining bipolar electrochemical processes into a nanopore. The reported concept of this new methodology may lead to intriguing new analytical and micro-structuring applications based on a temporal pattern in ionic current responses and based on a spatial pattern leading to micro-ring nanoassembly
Electrodeposition of Gold Nanostructures at the Interface of a Pickering Emulsion

The controlled electrodeposition of nanoparticles at the surface of an emulsion droplet offers enticing possibilities in regards to the formation of intricate structures or fine control over the locus or duration of nanoparticle growth. In this work we develop electrochemical control over the spontaneous reduction of aqueous phase Au(III) by heterogeneous electron transfer from decamethylferrocene present in an emulsion droplet – resulting in the growth of nanoparticles. As gold is a highly effective conduit for the passage of electrical current, even on the nanoscale, the deposition significantly enhances the current response for the single electron transfer of decamethylferrocene when acting as a redox indicator. The nanostructures formed at the surface of the emulsion droplets were imaged by cryo‐TEM, providing an insight into the types of structures that may form when stabilised by the interface alone, and how the structures are able to conduct electrons
Probing the 3‐step Lithium Storage Mechanism in CH3NH3PbBr3 Perovskite Electrode by Operando‐XRD Analysis

This is the pre-peer reviewed version of the following article: Probing the 3‐step Lithium Storage Mechanism in CH3NH3PbBr3 Perovskite Electrode by Operando‐XRD Analysis, which has been published in final form at: https://doi.org/10.1002/celc.201801291. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Organic‐inorganic hybrid materials have gradually become one of the most actively studied research fields due to their fascinating properties. The reaction between lithium and organic‐inorganic halide perovskite has just recently been proposed. However, the exact mechanisms taking place in this electrode material have not been fully elucidated, yet. To shed light on these processes an operando‐X‐ray diffraction study has been performed and is reported herein. According to our results the lithiation of CH3NH3PbBr3 entails three reaction steps, distinguishable during the initial galvanostatic lithiation for different Li‐ion molar content x: (1) the initial Li+ insertion into the perovskite phase in which pure perovskite and lithiated phases coexist (0 <x<1), (2) the perovskite conversion reaction leading to the formation of metallic lead (1 <x<2), and finally, (3) the alloying of lithium with the metallic lead previously formed. In more detail, for x>0.3, the formation of a Lix:CH3NH3PbBr3 phase with distinctive X‐ray diffraction peaks is clearly detected, which coexists with the pristine material, till abruptly both phases disappear at x∼1 and CH3NH3Br and Pb metal are formed. It is shown that this conversion reaction is an irreversible process. The proposed mechanism for lithium storage gives a complete perspective of the complex structural environment involving the use of perovskite materials as electrodes for Li‐ion batteries
The impact of temperature variations on spectroscopic calibration modelling: a comparative study

Temperature fluctuations can have a significant impact on the repeatability of spectral measurements and as a consequence can adversely affect the resulting calibration model. More specifically, when test samples measured at temperatures unseen in the training dataset are presented to the model, degraded predictive performance can materialise. Current methods for addressing the temperature variations in a calibration model can be categorised into two classes—calibration model based approaches, and spectra standardisation methodologies. This paper presents a comparative study on a number of strategies reported in the literature including partial least squares (PLS), continuous piecewise direct standardisation (CPDS) and loading space standardisation (LSS), in terms of the practical applicability of the algorithms, their implementation complexity, and their predictive performance. It was observed from the study that the global modelling approach, where latent variables are initially extracted from the spectra using PLS, and then augmented with temperature as the independent variable, achieved the best predictive performance. In addition, the two spectra standardisation methods, CPDS and LSS, did not provide consistently enhanced performance over the conventional global modelling approach, despite the additional effort in terms of standardising the spectra across different temperatures. Considering the algorithmic complexity and resulting calibration accuracy, it is concluded that the global modelling (with temperature) approach should be first considered for the development of a calibration model where temperature variations are known to affect the fundamental data, prior to investigating the more powerful spectra standardisation approaches. Copyright © 2007 John Wiley & Sons, Ltd
Raw data pre-processing in the protozoa and metazoa identification by image analysis and multivariate statistical techniques

Different protozoa and metazoa populations develop in the activated sludge wastewater treatment processes and are highly dependent on the operating conditions. In the current work the protozoa and metazoa groups and species most frequent in wastewater treatment plants were studied, mainly the flagellate, sarcodine, and ciliate protozoa as well as the rotifer, gastrotrichia, and oligotrichia metazoa.
The work is centered on the survey of the wastewater treatment plant conditions by protozoa and metazoa population using image analysis, discriminant analysis (DA), and neural networks (NNs) techniques, and its main objective was set on the evaluation of the importance of raw data pre-processing techniques in the final results. The main pre-processing techniques herein studied
were the raw parameters reduction set by a joint cross-correlation and decision trees (DTs) procedure and two data normalization techniques: logarithmic normalization and standard deviation normalization.
Regarding the parameters reduction methodology, the use of a joint DTs and correlation analysis (CA) procedure resulted in 28 and 30% reductions in terms of the initial parameters set for the stalked and non-stalked microorganisms, respectively. Consequently, the use of the reduced
parameters set has proven to be a suitable starting point for both the DA and NNs methodologies, although for the DA an initial logarithmic normalization step is advisable. For the NNs analysis a standard deviation normalization procedure could be considered for the non-stalked microorganisms
regarding the operating parameters assessment.National Council of Scientific and Technological Development of Brazil (CNPq)
BI-EURAM III ALFA co-operation project (European Commission) 
(UFPE, Recife, Brasil)
Fundação para a Ciência e a Tecnologia (FCT
Blind decomposition of low-dimensional multi-spectral image by sparse component analysis

Multilayer hierarchical alternating least square nonnegative matrix factorization approach has been applied to blind decomposition of low-dimensional multi-spectral image. Performance of the algorithm is invariant with respect to statistical (in)dependence between materials present in the image that is an assumption upon which many existing blind source separation methods depend. The proposed method performs blind decomposition exploiting spectral diversity and spatial sparsity between the materials present in the image. Unlike many existing blind source separation methods the method is capable to estimate the unknown number of materials present in the image. This number can be less than, equal to or greater than the number of spectral bands. Performance of the method is evaluated on underdetermined blind source separation problems associated with blind decompositions of experimental red-green-blue images composed of four materials. The proposed algorithm showed best performance in comparison with methods based on -norm minimization: linear programming and interior-point methods. In addition to tumor demarcation problem demonstrated in the paper, other areas that can also benefit from proposed method are cell and chemical imaging
Gaussian mixture models for the classification of high-dimensional vibrational spectroscopy data

Special Issue: Herman Wold Medal Winners 2007-2009International audienceIn this work, a family of generative Gaussian models designed for the supervised classification of high-dimensional data is presented as well as the associated classification method called High Dimensional Discriminant Analysis (HDDA). The advantages of these Gaussian models are: i) the representation of the input density model is smooth; ii) the data of each class are modeled in a specific subspace of low dimensionality; iii) each class may have its own covariance structure; iv) regularization is coupled to the classification criterion to avoid data over-fitting. To illustrate the abilities of the method, HDDA is applied on complex high-dimensional multi-class classification problems in mid-infrared and near infrared spectroscopy and compared to state-of-the-art methods