We report 3 experiments examining the effects of positive versus negative valence and perceptual load in determining attention capture by irrelevant emotional distractors. Participants performed a ...letter search task searching for 1 of 2 target letters (X or N) in conditions of either low perceptual load (circular nontarget letters) or high perceptual load (angular nontarget letters that are similar to the target letters). On 25% of the trials an irrelevant emotional distractor was presented at the display center and participants were instructed to ignore it. The distractor stimulus was either positive or negative and was selected from 3 different classes: IAPS pictures of erotica or mutilated bodies (Experiment 1), happy or angry faces (Experiment 2), and faces associated with gain or loss in a prior value-learning phase involving a betting game (Experiment 3). The results showed a consistent pattern of interaction of load and valence across the 3 experiments. Irrelevant emotional distractors produced interference effects on search reaction time (RT) in conditions of low load, with no difference between negative and positive valence. High perceptual load, however, consistently reduced interference from the negative-valence distractors, but had no effect on the positive-valence distractors. As these results were consistently found across 3 different categories of emotional distractors, they suggest the general conclusion that attentional capture by irrelevant emotional distractors depends on both their valence and the level of perceptual load in the task and highlight the special status of distractors associated with pleasure.
Quaternary chalcogenide Ge15-xSbxSe50Te35, (0.0≤x≤15.0, at. %) thin films are prepared using the thermal evaporation process under the residual vacuum pressure of ≈ 10−3 Pa. The rate of deposition ...and thicknesses of the film samples are kept constant at 10 nm/s and 200 nm, respectively. X-ray diffraction is employed to examine the amorphous or crystalline structure of films. The absence of sharp and distinct peaks confirms the amorphous nature. The compositional element ratio of all prepared samples is analysed by energy-dispersion X-ray spectroscopy technique. UV–Vis–NIR absorption spectra are used to study the optical parameters of thin films. The values of the absorption coefficient for all film samples are found to be higher than 104 cm −1. The optical band-gap energy is determined both experimentally and theoretically. The band gap is due to the indirect electronic transitions, and the band gap values are found to decrease from 1.047 eV to 0.864 eV with the increase in Sb-ratio. The band-tail width increases from 0.103 eV to 0.258 eV. The optical density, skin effect and extinction coefficient increase with an increase in Sb-content. The positions of the conduction and valence bands, as well as the conduction potentials of all samples, are also evaluated. The Fermi level shifts closer to the valence band and away from the conduction band with increasing Sb content. The chemical bond approach model is applied to study the cohesive energy and average-coordination number of these a-Ge-Sb-Se-Te films. The total number of constraints, floppy modes, cross-linking density, the number of the valence electrons and the number of lone-pair electrons are also investigated. All discussed parameters are found to be strongly dependent on the Sb-content.
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Despite substantial progresses, in aqueous zinc ion batteries (AZIBs), developing zinc metal anodes with long‐term reliable cycling capabilities is nontrivial because of dendritic growth and related ...parasitic reactions on the zinc surface. Here, we exploit the tip‐blocking effect of a scandium (Sc3+) additive in the electrolyte to induce uniform zinc deposition. Additional to the tri‐valency of Sc3+, the rigidity of its hydration shell effectively prevents zinc ions from concentrating at the surface tips, enabling highly stable cycling under challenging conditions. The shell rigidity, quantified by the rate constant of the exchange reaction (kex), is established as a key descriptor for evaluating the tip‐blocking effect of redox‐inactive cations, explaining inconsistent results when only the valence state is considered. Moreover, the tip‐blocking effect of Sc3+ is maintained in blends with organic solvents, allowing the zinc anode to cycle reliably even at −40 °C without corrosion.
In aqueous zinc ion batteries, Sc3+ with low water exchange rate constant (kex) has a dynamically rigid solvation shell, holding onto its spatial occupation and thus preventing zinc ions from concentrating near tips on the zinc metal surface towards indiscriminate dendrite growth. The rigidity of solvation shells of redox‐inactive cations is proposed as a descriptor in determining the tip‐blocking effect.
A tungsten mixed-valance polythio complex and a η2-dithioacetate chromium complex has been isolated and characterized.
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•A trinuclear tungsten oxo-polythio mixed valance complex ...{Cp*WCl(μ-S)2}2WO, 1 is synthesized.•An efficient method for the synthesis of a η2-dithioacetate chromium complex Cp*Cr(CO)2(η2-S2CCH3), 2 is established.
The structures and bonding of polythio complexes having group 6 metals are described. A trinuclear tungsten mixed valence complex, {Cp*WCl(μ-S)2}2WO, 1 along with known syn-(Cp*WS)2(µ-S)2 and anti-(Cp*WS)2(µ-S)2 are synthesized by the thermolysis reaction of Cp*WCl4 with LiBH4·THF followed by addition of 2-mercaptobenzothiazole (MBT-C7H5NS2). The electronic properties of these complexes associated with central metal atoms have been evaluated through UV–vis absorption spectra. Further, a η2-dithioacetate chromium complex, Cp*Cr(CO)2(η2-S2CCH3), 2 was synthesized by the reaction of Cp*Cr(CO)3Me with LiBH4·THF followed by the treatment of carbon disulfide (CS2). Both complexes 1 and 2 were characterized using multinuclear NMR, IR spectroscopy, mass spectrometry, as well as single-crystal X-ray diffraction. In addition, density functional theory (DFT) calculations were conducted to interpret and study the nature of bonding and electronic structures of 1 and 2.
In many decision problems, outcomes are not reached after a single action but rather after a series of events or states. To optimize decisions over multiple states, representations of how good or bad ...the outcomes are, that is, the outcomes' valence, should spread across states. One mechanism for valence spreading is a temporal, state-independent process in which a single valence representation is updated when an outcome is experienced and fades away afterwards. Each state's valence is based on its temporal proximity to the experienced outcome. An alternative, state-dependent mechanism relies on the structure of transitions between states, updating a separate valence representation for each state according to its spatial distance from the outcomes. We examined how these mechanistic accounts shape the spread of two formats of valence representation, feelings (affective valence) and knowledge (semantic valence), between states. In two pre-registered experiments (N = 585), we used a novel task in which participants move in a four-state maze, one of which contains an outcome. The participants provide self-reports of affective and semantic valence throughout the maze and after finishing it. Results show that the affective representation of negative valence is more localized in state-space than the semantic representation. We also found evidence for the relative reliance of the affective valence on a temporal, state-independent mechanism and of the semantic valence on a structured, state-dependent mechanism. Our findings provide mechanistic accounts for the differences between affective and semantic valence representations and indicate how such representations may play a role in associative learning and decision-making.
A new pseudocapacitor anode, sulfur‐doped V6O13−x, is reported. It achieves a benchmark capacitance of 1353 F/g (0.72 F/cm2) at a current density of 1.9 A/g (1 mA/cm2) in 5 M LiCl solution. The ...charges are stored chemically in the electrode via reversible redox reactions that involve multiple oxidation states of vanadium (V3+, V4+ and V5+).
Valence tuning of transition metal oxides is an effective approach to design high‐performance catalysts, particularly for the oxygen evolution reaction (OER) that underpins solar/electric water ...splitting and metal‐air batteries. Recently, high‐valence oxides (HVOs) are reported to show superior OER performance, in association with the fundamental dynamics of charge transfer and the evolution of the intermediates. Particularly considered are the adsorbate evolution mechanism (AEM) and the lattice oxygen‐mediated mechanism (LOM). High‐valence states enhance the OER performance mainly by optimizing the eg‐orbital filling, promoting the charge transfer between the metal d band and oxygen p band. Moreover, HVOs usually show an elevated O 2p band, which triggers the lattice oxygen as the redox center and enacts the efficient LOM pathway to break the “scaling” limitation of AEM. In addition, oxygen vacancies, induced by the overall charge‐neutrality, also promote the direct oxygen coupling in LOM. However, the synthesis of HVOs suffers from relatively large thermodynamic barrier, which makes their preparation difficult. Hence, the synthesis strategies of the HVOs are discussed to guide further design of the HVO electrocatalysts. Finally, further challenges and perspectives are outlined for potential applications in energy conversion and storage.
High valence oxides of transition metals represent an emerging group of valence‐engineered catalysts, capable of offering very high catalytic activity and stability. The mechanisms of such “unconventional” characteristics and their synthesis strategies are discussed here. The case for oxygen evolution reaction is reviewed to guide effective development of the catalytic structures for water‐splitting hydrogen generation and metal‐air batteries.
The sodium superionic conductor (NASICON)‐Na3V2(PO4)3 (NVP) is an attractive cathode for sodium‐ion batteries, which is still confronted with limited rate performance due to its low electronic ...conductivity. In this paper, a chemical strategy is adopted to partially replace V3+ of the NVP framework by low‐valence Mn2+ and high‐valence Mo6+ substitution. The crystal structure, sodium‐ion diffusion coefficient and electrochemical performance of Mn−Mo‐doped Na3.94V0.98Mo0.02Mn(PO4)3@C cathode were investigated. X‐ray diffraction confirmed the NASICON‐type structure and XPS analysis confirmed the oxidation state of Mn and Mo in doped NVP cathode. The Na ion diffusion processes were inferred from Cyclic Voltammetry (CV), Galvanostatic intermittent titration technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) measurement, which clearly show rapid Na‐ion diffusion in NASICON‐type cathode materials. The Mn−Mo‐substituted NVP shows smoother charge‐discharge profiles, improved rate performance (64.80 mAh/g at 1 C rate), better energy density (308.61 mWh/g) and superior Na‐ion kinetics than that of unsubstituted NVP@C cathode. Their enhanced performance is attributed to large interstitial volume mainly created by high valence Mo6+ and enhanced capacity is attributed to the low valence Mn2+ doping. These results demonstrate that Mn−Mo‐doped NVP cathode is strongly promising cathode material for sodium‐ion batteries.
A chemical strategy is adopted to partially replace V3+ in the sodium superionic conductor (NASICON)‐Na3V2(PO4)3 (NVP) by low‐valence Mn2+ and high‐valence Mo6+ substitution. The Mn−Mo‐substituted NVP shows smoother charge‐discharge profiles, improved rate performance (64.80 mAh/g at 1 C rate), better energy density (308.61 mWh/g), and superior Na‐ion kinetics compared to unsubstituted NVP@C cathodes.
Efficiently photodegradation of 2-chlorophenol via preferential dechlorination on Z-scheme valence-mixed FePc/(100) BMO heterojunction with enhanced charge separation and Fe0/Fe2+ sites.
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•Ultrathin (100)-BMO nanosheets with selective 2-CP adsorption were synthesized.•H-FePc/BMO heterojunction was prepared via H-bond assembly and H2– treatment.•Preferential dechlorination on BMO facilitate 2-CP degradation.•Z-scheme charge transfer between H-FePc and BMO enhanced charge separation.•Fe0/Fe2+ species promoted O2 activation to further improve the activity.
It is vital for selectively preferential dechlorination by visible-light photocatalysis to eliminate high-risk 2-chlorophenol (2-CP) contaminant. However, selective adsorption and efficient charge separation remain challenging. Herein, ultrathin (100) facet-exposed Bi2MoO6 (BMO) nanosheets (∼6 nm thickness) with enhanced selective adsorption for 2-CP due to the Bi-Cl interaction and highly visible-light activity for 2-CP degradation have been synthesized via a pH-controlled microwave-assisted hydrothermal process. The visible-light activity could be improved by modifying iron phthalocyanines (FePc) via H-bond induced assembly and subsequent H2 thermal treatment. The visible-light activity of as-optimized H2-treated heterojunction (H-FePc/BMO) was 4.5 and 2.5-time higher than BMO and FePc/BMO. Raman spectra, X-ray photoelectron spectrum, electron paramagnetic resonance, photoelectrochemical measurements, radical trapping experiment and ion chromatography, confirmed that the improved photoactivity of H-FePc/BMO could be attributed to the selective adsorption of 2-CP inducing photogenerated-holes as dominating active species with nearly 100% preferential dechlorination, the enhanced charge separation via Z-scheme transfer and the promoted O2 activation from valence-mixed Fe0/Fe2+ species in FePc after H2 treatment. This study may open up a new way to the high-efficiency degradation of chlorophenols using bismuth-containing oxide-based photocatalysts.
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