Codeposition of Platinum and Gold on Nickel Wire Electrodes via Galvanic Replacement Reactions for Electrocatalytic Oxidation of Alcohols

Codeposition of Pt and Au on Ni wire was performed using a simple treatment of immersing Ni wire in aqueous solutions containing both K₂PtCl₄ and HAuCl₄. For evaluating the electrochemical properties of the thus-prepared electrodes, cyclic voltammograms (CVs) of 1.0 M ethanol in 1.0 M NaOH aqueous solutions were recorded. Compared with Pt- or Au-deposited Ni wire electrodes prepared by treating Ni wire in aqueous solutions of a single component, e.g., 1.0 mM K₂PtCl₄ or 1.0 mM HAuCl₄, a noteworthy increase in the electrocatalytic current was observed for the oxidation of ethanol with a PtAu-codeposited Ni (PtAu/Ni) wire electrode even when it was prepared in an aqueous solution containing both 0.10 mM K₂PtCl₄ and 0.10 mM HAuCl₄. In addition, the shape and the peak potentials of CVs recorded using PtAu/Ni wire electrodes were found to be different from those recorded with the Pt- or Au-deposited Ni wire electrodes. Because the CV responses typical of the PtAu/Ni wire electrodes were observed even when a PtAu/Ni wire electrode was prepared in an aqueous solution containing both 0.010 mM K₂PtCl₄ and 1.0 mM HAuCl₄, it is considered that a small amount of Pt was effectively modified or incorporated and affected the electrochemical properties significantly. The CV results for ethanol oxidation were compared with those for the electrocatalytic oxidations of methanol, 1-propanol, and 2-propanol. Besides, the CV results recorded with the present PtAu/Ni wire electrodes are discussed in comparison with some previous results obtained using other PtAu nanoelectrocatalysts

Modification with platinum of silver-deposited nickel wire electrodes for electrocatalytic oxidation of alcohols

A silver-deposited nickel (Ag/Ni) wire electrode was prepared via a galvanic replacement reaction between Ag⁺ and Ni wire in aqueous solution. It was then found that the Ag/Ni wire electrode could be modified with Pt simply by treating it in an aqueous solution of K₂PtCl₄. Although the deposition of Ag on Ni wire was limited in amount, forming Ag deposits less than 100 nm in size, a considerable increase in the electrocatalytic currents for the oxidation of alcohols could be observed after further modification of the Ag/Ni wire electrodes with Pt. This is in contrast to the fact that it was difficult to produce sufficient electrocatalytic response by modifying Ni wire with Pt directly via a simple galvanic replacement between PtCl₄²⁻ and Ni wire. Thus, the prior deposition of Ag was found to strongly promote modification with Pt via a simple stepwise treatment using AgNO₃ and K₂PtCl₄. This approach should be effective in modifying various Ni materials with Pt, including Ni microparticles

Petrography and geochemistry of the enriched basaltic shergottite Northwest Africa 2975

We present a study of the petrology and geochemistry of basaltic shergottite Northwest Africa 2975 (NWA 2975). NWA 2975 is a medium-grained basalt with subophitic to granular texture. Electron microprobe (EMP) analyses show two distinct pyroxene compositional trends and patchy compositional zoning patterns distinct from those observed in other meteorites such as Shergotty or QUE 94201. As no bulk sample was available to us for whole rock measurements, we characterized the fusion crust and its variability by secondary ion mass spectrometer (SIMS) measurements and laser ablation inductively coupled plasma spectroscopy (LA-ICP-MS) analyses as a best-available proxy for the bulk rock composition. The fusion crust major element composition is comparable to the bulk composition of other enriched basaltic shergottites, placing NWA 2975 within that sample group. The CI-normalized REE (rare earth element) patterns are flat and also parallel to those of other enriched basaltic shergottites. Merrillite is the major REE carrier and has a flat REE pattern with slight depletion of Eu, parallel to REE patterns of merrillites from other basaltic shergottites. The oxidation state of NWA 2975 calculated from Fe-Ti oxide pairs is NNO-1.86, close to the QFM buffer. NWA 2975 represents a sample from the oxidized and enriched shergottite group, and our measurements and constraints on its origin are consistent with the hypothesis of two distinct Martian mantle reservoirs: a reduced, LREE-depleted reservoir and an oxidized, LREE-enriched reservoir. Stishovite, possibly seifertite, and dense SiO_2 glass were also identified in the meteorite, allowing us to infer that NWA 2975 experienced a realistic shock pressure of ~30 GPa

In silico screening of potentially bioactive-anti-functional dyspepsia constituents of Magnoliae officinalis Cortex based on molecular docking and network pharmacology

Purpose: To screen for bioactive anti-functional dyspepsia compounds from Magnoliae officinalis Cortex (Hou Po) and to identify the mechanism(s) of action involved.Methods: The compounds of Hou Po were collected from the literature. The related target proteins were identified from DrugBank. Through  “Libdock” module of Discovery Studio 3.5, the compounds were matched with related target proteins. Taking the Libdock score of the original ligand with target protein as standard, components with higher scores than this standard were considered as potential bioactive compounds. Based on Cytoscape software, the interaction networks of the bioactive compound-target protein complexes were mapped. On the other hand, the online DAVID database was used to analyze the GO enrichment and KEGG pathway of each target.Results: A total of 199 chemical constituents and 13 correlated target proteins were obtained. One hundred and thirty-nine (139) potential bioactive constituents were acquired based on molecular docking. Thirty-one (31) bioactive compounds were selected based on degree values in networkanalysis. “Palmitone” and “magnolignan G” which had the highest degree values were considered promising and leading compounds. The result of gene enrichment analysis showed that the bioactive compounds exerted their effects mainly via “neuroactive ligand-receptor interaction” pathway and “Cholinergic synapse” pathways.Conclusion: Based on molecular docking and network pharmacology technique, the material basis for the use of Hou Po in the treatment of FD has been revealed. This finding provides a useful guide in the development of Hou Po-based anti-FD drugs. Keywords: Magnolia officinalis, Hou Po, Molecular docking, Functional dyspepsia, Network pharmacolog

Superior energy-storage properties in (Pb,La)(Zr,Sn,Ti)O-3 antiferroelectric ceramics with appropriate La content

Antiferroelectric (AFE) ceramics based on Pb(Zr,Sn,Ti)O3 (PZST) have shown great potential for applications in pulsed power capacitors because of their fast charge-discharge rates (on the order of nanoseconds). However, to date, it has been proven very difficult to simultaneously obtain large recoverable energy densities Wre and high energy efficiencies η in one type of ceramic, which limits the range of applications of these materials. Addressing this problem requires the development of ceramic materials that simultaneously offer a large ferroelectric-antiferroelectric (FE-AFE) phase-switching electric field EA, high electric breakdown strength Eb, and narrow polarization-electric field (P-E) hysteresis loops. In this work, via doping of La3+ into (Pb1-1.5xLax)(Zr0.5Sn0.43Ti0.07)O3 AFE ceramics, large EA and Eb due to respectively enhanced AFE phase stability and reduced electric conductivity, and slimmer hysteresis loops resulting from the appearance of the relaxor AFE state, are successfully obtained, and thus leading to great improvement of the Wre and η. The most superior energy storage properties are obtained in the 3 mol% La3+-doped (Pb1-1.5xLax)(Zr0.5Sn0.43Ti0.07)O3 AFE ceramic, which simultaneously exhibits at room temperature a large Wre of 4.2 J/cm3 and a high η of 78%, being respectively 2.9 and 1.56 times those of (Pb1-1.5xLax)(Zr0.5Sn0.43Ti0.07)O3 AFE ceramics with x = 0 (Wre = 1.45 J/cm3, η = 50%) and also being superior to many previously published results. Besides, both Wre and η change very little in the temperature range of 25–125 °C. The large Wre, high η, and their good temperature stability make the Pb0.955La0.03(Zr0.5Sn0.43Ti0.07)O3 AFE ceramic attractive for preparing high pulsed power capacitors useable in various conditions

Furan-containing double tetraoxa[7]helicene and its radical cation

An unprecedented furan-based double oxa[7]helicene 1 was achieved, featuring a stable twisted conformation with π-overlap at both helical ends. The excellent conformational stability allowed for optical resolution of 1, which provided a pair of enantiomers exhibiting pronounced mirror-imaged circular dichroism and circularly polarized luminescence activity. The radical cation of 1 was obtained by chemical oxidation as evidenced by UV-Vis-NIR absorption, electron paramagnetic resonance spectroscopy and in situ spectroelectrochemistry. The present work is the starting point for the investigation of open-shell oxahelicenes

Constrained L1-Norm Minimization Method for Range-Based Source Localization under Mixed Sparse LOS/NLOS Environments

Under mixed sparse line-of-sight/non-line-of-sight (LOS/NLOS) conditions, how to quickly achieve high positioning accuracy is still a challenging task and a critical problem in the last dozen years. To settle this problem, we propose a constrained L1 norm minimization method which can reduce the effects of NLOS bias for improve positioning accuracy and speed up calculation via an iterative method. We can transform the TOA-based positioning problem into a sparse optimization one under mixed sparse LOS/NLOS conditions if we consider NLOS bias as outliers. Thus, a relatively good method to deal with sparse localization problem is L1 norm. Compared with some existing methods, the proposed method not only has the advantages of simple and intuitive principle, but also can neglect NLOS status and corresponding NLOS errors. Experimental results show that our algorithm performs well in terms of computational time and positioning accuracy

Bismuth ferrite materials for solar cells: Current status and prospects

Different from classical semiconductor photovoltaic devices, for ferroelectric photovoltaic devices, the open-circuit voltage (Voc) can be four and even more orders of magnitude larger than the band gap of the ferroelectric, and the built-in electric field arising from the remnant polarization of the ferroelectric is throughout the bulk region, which is good for obtaining giant power conversion efficiency. Among ferroelectric materials, BiFeO3 with remnant polarization of as high as ∼100 μC/cm2 has the narrowest direct band gap (∼2.7 eV). These indicate that high power conversion efficiency may be obtained in BiFeO3-based photovoltaic devices. Also, some significant research results about photovoltaic effects of BiFeO3 materials have been recently acquired. In order to better promote the development of BiFeO3-based photovoltaic devices, in this paper, we present a comprehensive review on the latest research progress in photovoltaic effects of BiFeO3 materials with different kinds of topography, including bulk, thin film, and nanomaterials

Three-dimensional printing models in congenital heart disease education for medical students: a controlled comparative study

Abstract Background This study sought to assess, using subjective (self-assessment) and objective (MCQ) methods, the efficacy of using heart models with ventricular septal defect lesions produced with three-dimensional printing technology in a congenital heart disease curriculum for medical students. Methods Three computed tomography datasets of three subtypes of ventricular septal defects (perimembranous, subarterial and muscular, one for each) were obtained and processed for building into and printing out 3D models. Then a total of 63 medical students in one class were randomly allocated to two groups (32 students in the experimental, and 31 the control). The two groups participated in a seminar with or without a 3D heart model, respectively. Assessment of this curriculum was carried out using Likert-type questionnaires as well as an objective multiple choice question test assessing both knowledge acquisition, and structural conceptualization. Open-ended questions were also provided for getting advice and suggestion on 3D model utilization in CHD education. Results With these 3D models, feedback shown in the questionnaires from students in experimental group was significantly more positive than their classmates in the control. And the test results also showed a significant difference in structural conceptualization in favor of the experimental group. Conclusion It is effective to use heart models created using current 3D printing technology for congenital heart disease education. It stimulates students’ interest in congenital heart disease and improves the outcomes of medical education

Optimal selection and effect evaluation of re-fracturing intervals in shale gas horizontal wells

The monitoring results of production logging show that almost one third of perforation clusters produce no or less gas after volumetric fracturing is initially applied in shale gas reservoirs. Besides, the production decline after the commissioning is commonly faster. In this paper, a fracture network prediction model and a fracturing well productivity prediction model were established based on microseismic interpretation data and hydraulic fracture network propagation results. After petrophysics, microseism, production performance were taken into consideration comprehensively, shale re-fracturing development potential evaluation index (RDPEI) was proposed. Then, a re-fracturing design and evaluation method was developed and targeted interval selection and evaluation was realized and applied on site. And the following research results were obtained. First, due to the heterogeneity of natural fractures, hydraulic fracture networks are more different, so an obvious “dead gas zone” can be easily formed and its re-fracturing potential is high. Second, the initial hydraulic fracture network is more affected by natural fractures. The main part of a fracture network propagates along the direction of maximum horizontal major stress, the fractures in regional stimulated intervals propagate in the form of double wing, and the length of a liquid swept fracture network is 52–70% of seismic interpretation result. Third, the RDPEI model avoids the limitations of single factor analysis and realizes the quantitative prediction on three types of indexes of recoverability, compressibility and re-fracturing. Fourth, re-fracturing of the case well is remarkable in stimulation effect. Its shale gas productivity is increased by 38.9%, and its cumulative gas production in one year is increased by 62.5%. In conclusion, re-fracturing is an effective and feasible method for improving the single well ultimate recovery reserves of shale gas. This method provides a theoretical and technical support for the selection and effect evaluation of re-fracturing intervals in shale-gas horizontal wells. Keywords: Shale gas, Re-fracturing, Productivity, Prediction, Fracture network propagation, Microseismic, Production decline, Single-well ultimate recoverable reserve