Valence Properties Research Articles

Combining real-space and local range separation-The MH24 locally range-separated local hybrid functional.

In this work, the development of a new general-purpose exchange-correlation hybrid functional based on the recent locally range-separated local hybrid approach is presented. In particular, the new functional, denoted as MH24, combines a non-empirical treatment of the admixture of locally range-separated long-range exact exchange with a new real-space separation approach for the real-space exact-exchange admixture governed by the local mixing function (LMF) and a new empirical LYP-based approach for the correlation functional to enable a flexible description of same- and opposite-spin correlation effects. The nine empirical parameters of the MH24 model have been optimized using a state-of-the-art super-self-consistent-field approach, which exploits the sensitivity of specific properties, such as core ionization potentials, electron affinities, and atomization energies, to the exact-exchange admixture in specific regions in real space and the separation of the LMF into a core, valence, and asymptotic part. The optimized MH24 functionals are shown to be able to simultaneously provide good accuracy for valence and core properties as well as for electron affinities and noble gas dimer dissociation curves, while satisfying multiple known exact constraints related to the exact-exchange admixture in hybrid functionals. MH24 is thus a major step toward the development of more sophisticated hybrid functional models.

Correlation of Valence electron structure and properties of monolayer graphene and MX2 (M=Mo, W; X=S, Se, Te): Empirical Electron Theory (EET) investigation

The atomically thin layers of transition-metal dichalcogenide (TMDC) materials have garnered considerable attention due to their exceptional electrical, optical, mechanical, and thermal properties. Hence, it is important to investigate the mechanism of their excellent properties. In this paper, the study is focused on the correlation between valence electron structures (VESs) and mechanical as well as thermal properties of graphene and MX2 (M = Mo, W; X = S, Se, Te) for revealing their essential mechanisms of properties with an empirical electron theory (EET). A model of Young's modulus is built for the monolayer graphene and MX2 (M = Mo, W; X = S, Se, Te) based on the VES, which has been verified by the observed ones of elements in the 4th to 6th periods in the periodic table of elements. The calculated bond lengths and mechanical and thermal properties of graphene and MX2 are in good agreement with experimental ones. The study reveals that the thermal and mechanical properties of MX2 strongly depend on their valence electron structures. It shows that the melting point, cohesive energy, thermal conductivity, and Young's modulus are modulated by covalence electron pair nA, the averaged covalence electron per atom nc/atom, covalence electron pair nA and linear density of covalent electron on the strongest bond ρl, respectively. The study helps explain the thermal and mechanical properties of two-dimensional (2D) materials and also supplies a reference for their design with high performance by modulating their valence electron structures.

Electrical transport properties of topographically demorphed films of La1-xBaxMnO3 grown on (00l)-oriented LaAlO3 substrate via spin-coating method

Herein, the crystal structure, valence, and electrical transport properties of La1-xBaxMnO3 films were examined by preparing La1-xBaxMnO3 films with varying Ba content (x = 0.22, 0.24, 0.26, 0.28) on LaAlO3 substrates using the sol-gel spin coating technique. The La1-xBaxMnO3 films prepared in the study exhibit topographically demorphed and non-dense characteristics in the microstructure, which is mainly caused by the Volmer-Weber growth mode of the films and the volatilization of organic matter during the sol-gel sintering process for films preparation. The increase of Ba doping leads to MnO6 deformation, decrease in grain boundary scattering, increase in Mn4+ ion content, and enhancement of both the double exchange mechanism and the Jahn-Teller effect. The four-probe results showed that the peak resistivity of the films decreased significantly with the increase in Ba2+ doping, and the metal-insulator transition temperature (Tp) shifted to higher temperatures. Peak temperature coefficient of resistivity (TCR) corresponding temperature (Tk) increased from 283.05 K (x = 0.22) to 309.31 K (x = 0.28), which was consistent with the trend of Tp; the peak value of TCR decreased with the increase of Ba doping. When x = 0.24, the Tk of the La1-xBaxMnO3 films reach room temperature (294.25 K) with TCR = 9.01 % K−1. In conclusion, the electrical properties of La1-xBaxMnO3 can be optimized by varying the amount of Ba doping to obtain La1-xBaxMnO3 films with room-temperature Tk and higher TCR values, providing reasonable data support and theoretical explanation for the Ba doping mechanism.

An ultrafast, stable and highly reversible nickel magnesium vanadate cathode for magnesium ion batteries

Rechargeable magnesium batteries are one among the strongest candidates over lithium ion batteries with abundance, cost effective and less environmental hazard. However, limitations including slow Mg2+ ion kinetics in the electrode-electrolyte interface and formation of passivating layers on the surface of magnesium metal anode affecting the rechargeable behavior of a cathode. Herein, hydrothermally synthesized NiMg2(VO4)2 nanomaterial used as cathode. The oxidation and reduction properties of Mg and V facilitates the diffusion pathway for Mg2+ and Li+ ions. Additionally, the employment of activated carbon cloth as anode diminishes the strong ionic interactions between Mg2+ ions and crystal lattice, enabling the faster diffusion of Mg2+ ions. All the electrochemical investigations are carried out at room temperature in the potential window of 1.23 V to 3.83 V against Mg/Mg2+. At a lower current density of 100 mA g−1, the specific discharge capacity have been 220 mAh g−1 for the 2nd cycle and retention of 97.1 % over 25 cycles. The specific capacity increases with more Mg2+ involvement in the reaction. At the highest current rate of 5000 mA g−1 the capacity retention is 96.8 % after 1000 cycles. Calculated energy density for a low current density is 556 Wh kg−1. The presence of multivalent V ions in the cathode reduces volume expansion, assisting charge redistribution to maintain electroneutrality. The dynamic valence property of. Vanadium ions (V2+/V5+) assist the intercalation of Mg2+ ions into the crystal lattice of cathode and possibly contribute to the highly stable and reversible discharge capacity over cycles. These findings provide a new perspective on NiMg2(VO4)2 as cathode material for magnesium ion batteries.

Disentangling inhibition toward food and non-food stimuli across two hunger levels: An fNIRS study

While individuals tend to display poorer inhibitory control toward food-related than neutral stimuli, it is unclear whether this challenge is specific to food or extends to other pleasant stimuli. Uncertainty also remains regarding the general impact of hunger on inhibition. To address these questions, we used a within-subjects design whereby 44 healthy adults completed two go/no-go tasks including no-go images of highly palatable foods and no-go images of animals matched for valence and physical properties. Both tasks were completed one week apart in either a fed or a fasted state. Prefrontal cortex activity was measured using functional near-infrared spectroscopy. Poorer behavioral inhibition was observed when participants needed to withhold their response to images of food compared to animals, regardless of hunger state. In addition, more commission errors were made in the fasted compared to the fed condition, regardless of the type of image to avoid responding to. Responses to go trials were slower when these trials were interspersed with food compared to animal no-go trials. However, hunger did not influence go response time. Greater activation was observed in the dorsolateral prefrontal cortex during blocks of trials with (vs. without) no-go images, but brain activity did not differ according to the type of no-go image. The effect of hunger on prefrontal brain activity was also not significant. Exploratory correlations showed that food-related inhibition deficits were positively related to self-reported impulsivity, but unrelated to body mass index. This study suggests that even among healthy adults, food-related inhibitory control may have a unique behavioral signature beyond general inhibition toward pleasant stimuli. Hunger also exerts an independent influence on general inhibitory capabilities, highlighting the importance of carefully controlling hunger levels in inhibition studies.

High-capacity and high-stability capacitive desalination with dual redox-active MnCo2S4/g-C3N4 heterojunction electrode

Capacitive deionization (CDI) utilizing dual redox-active electrodes has shown significant promise in desalinating low-concentration brackish waters, which is crucial for addressing global freshwater shortages. However, improvements in salt adsorption capacity and long-term operational stability are still required. In this study, we introduce, for the first time, a binary metal sulfide MnCo2S4/g-C3N4 (MCS-CN) heterojunction as a CDI electrode. The innovative integration of dual redox-active centers and heterojunction structures in the MCS-CN composite electrodes underscores their potential for achieving both high capacity and stability in capacitive desalination applications. The microscopic morphology, crystal structure, pore structure, and surface valence properties of the MCS-CN heterojunction composite materials were extensively characterized using various analytical techniques. In-situ X-ray diffraction, refined ex-situ X-ray photoelectron spectroscopy, three-electrode electrochemical analysis, and theoretical calculations were employed to elucidate the electrosorption and desorption mechanisms of sodium ions with the MCS-CN electrodes and to clarify the enhanced desalination performance of the binary metal sulfide-based heterojunction structure. As a result, the optimal MCS-CN-40 electrode exhibited the highest salt removal capacity of 71.64 mg g−1 and maintained stable desalination performance over 100 cycles in a 500 mg L−1 NaCl solution. This innovative approach provides a noval perspective for developing heterojunction electrodes with high redox activity and efficient desalination performance.

A novel magnesium reduction technique for the separation of ytterbium from non-aqueous solutions

The separation of heavy rare earth elements, particularly Tm, Yb, and Lu, poses significant challenges due to their small differences in ionic radii and close chemical properties. Utilizing the variable valence properties of ytterbium can simplify the separation from adjacent elements. Therefore, a novel magnesium reduction technique was proposed, offering selective reduction and separation of ytterbium. In comparison to traditional methods such as sodium amalgam reduction and mercury cathode reduction, this approach achieves efficient separation of ytterbium and lutetium without the need for mercury, rendering it more environmentally friendly and safe. Under a non-oxidizing nitrogen atmosphere, utilizing magnesium powder as the reducing agent and a mixed solution of 1,4-dioxane and ethanol as the reaction solvent, only 20 min are required to complete one reduction-precipitation operation for simulated solutions. This yields a recovery of 70.89% and a purity of 97.5% for ytterbium (II) chloride. The optimal experimental conditions obtained are applied to natural heavy rare earth mixed solutions, resulting in the recovery of over 90% of ytterbium after three reduction-precipitation processes. Post-ytterbium separation, the residual solution is enriched with approximately three times the amount of thulium and lutetium, greatly facilitating subsequent separation processes. This method liberates ytterbium reduction-separation from dependence on mercury, offering not only rapid and efficient processing but also significant industrial prospects.

The flexibility of pre-embedding Na+ and PO43- in layered V2O5 for high capacity and stability zinc ion batteries

To address the challenge of balancing high conductivity, capacity, and long-cycle stability in V2O5 cathode materials for aqueous zinc-ion batteries, we introduce an innovative strategy of co-embedding cations and anions into the layered V2O5 structure. We synthesized Na and P co-embedded layered V2O5 materials and systematically investigated their morphological structure, elemental valence, and electrochemical properties using X-ray diffraction, scanning electron microscopy, Fourier infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical characterization. The synthesized material demonstrated a high capacity of 357.8 mAh·g−1 at 0.2 A·g−1 and a remarkable capacity retention of 107.7 % after 2000 cycles at 4.0 A·g−1. These results highlight the synergistic effect of co-embedded ions and structured water, offering new insights into the insertion/extraction dynamics of pre-embedded ions, structured water, and zinc ions in layered V2O5.

Predykaty wyższego vs. pierwszego rzędu jako problem syntaktyczny

HIGHER-ORDER VS FIRST-ORDER PREDICATES AS A SYNTACTIC PROBLEM The author considers the problems of syntactic analysis of language expressions with higher-order and first-order predicates. In the first part it is shown that there are some discrepancies in the treatment of these categories: on the one hand, in semantic syntax, and, on the other hand, in predicate logic and in categorial grammar. In the following chapters, the author analyses the disputed phenomena that can be treated in two ways, depending on whether the verb is considered a first-order or higher-order predicate. At the same time, it is stated that the valence properties of a verb depend on its lexical meaning, and, on the other hand, the definition of meaning should take into account the nature of the syntactic structure. The notion of precedent representations is suggested, i. e. constructions with a clausal actant that indicate the propositional status of the appropriate complements of the predicate.

Improved electrical transport properties of La0.7Ca0.3−xKxMnO3 (0.0 ≤ x ≤ 0.3) films grown on La0.3Sr0.7Al0.65Ta0.35O3 (00l) substrates by sol–gel spin coating method

Herein, La0.7Ca0.3−xKxMnO3 (LCKMO) films with highly oriented growth were prepared on La0.3Sr0.7Al0.65Ta0.35O3 (00l) substrates by sol–gel spin coating method. Comprehensive analysis of microstructure, surface morphology, ion valence, and electrical transport properties of LCKMO films indicates that the substitution of K+ ions for Ca2+ ions increased the ratio of Mn4+/(Mn3+ + Mn4+), narrowed the one electron bandwidth, and enhanced double exchange mechanism and electron–lattice coupling. Moreover, the doping of K+ ions induced the dense and uniform conical-structured growth of grains on the surface of the films. Results demonstrated that at x = 0.1, LCKMO film exhibited the maximum TCR of 17.84% K−1 at 253.07 K, which was 31.76% higher than that of previously reported La1−x−yCaxKyMnO3 ceramic with the highest TCR. Further theoretical insights into the effects of Ca/K co-doping on electrical transport properties were supplemented.

Effect of oleic acid modified GO‐LaF3 on lubrication characteristics of 10# white oil

AbstractTo study the synergistic lubricating effects of graphene oxide (GO) and lanthanum fluoride (LaF3), and find a new anti‐wear additive, oleic acid surface‐modified graphene oxide‐lanthanum fluoride (OA‐GO‐LaF3, OGL) composite nano‐additive was prepared by hydrothermal method by using oleic acid as the modifier. The morphology, structure, composition, element valence, thermal stability and tribological properties of nano additives were characterised by a series of modern characterisation methods. Results show that OGL has a higher degree of graphitization, smaller particle size, more homogeneous disperse, higher LaF3 load and stronger thermal stability than that of GL. The tribological properties of OGL which is modified by oleic acid are better than unmodified GL. Analysis of the friction mechanism shows that both OGL and GL can generate LaF3 physical adsorption films through adsorption during the friction process and tribochemical reactions film containing lanthanum compounds, carbon oxide compounds, and iron oxide compounds on the friction surface. These physical adsorption films and chemical reaction film can improve lubrication.

A novel electrode for simultaneous detection of multiple heavy metal ions without pre-enrichment in food samples

Integrating a pre-enrichment step into electrochemical detection methodologies has traditionally been employed to enhance the performance of heavy metal detection. However, this augmentation also introduces a degree of intricacy into the sensing process and increases energy consumption. In this work, Mo-doped WO3 is grown in situ on carbon cloth by one-step electrodeposition. The electrode detect multiple heavy metal ions simultaneously in the range of 0.1–100.0 μM with LODs ranging from 11.2 to 17.1 nM. The electrode successfully detected heavy metal ions in diverse food samples. This pioneering detection strategy realized the direct and simultaneous detection of multiple heavy metal ions by utilizing the valence property of WO3 and oxygen vacancies generated by molybdenum doping. The Mo-WO3/CC pre-enrichment-free detection electrode boasts straightforward preparation, a streamlined detection procedure, swift response kinetics, and superior performance relative to previously reported electrodes, which makes it possible to develop a portable heavy metal ion detection device.

Competition between emotional faces in visuospatial working memory.

Visuospatial working memory (VSWM) helps track the identity and location of people during social interactions. Previous work showed better VSWM when all faces at encoding displayed a happy compared to an angry expression, reflecting a prosocial preference for monitoring who was where. However, social environments are not typically uniform, and certain expressions may more strongly compete for and bias face monitoring according to valence and/or arousal properties. Here, we used heterogeneous encoding displays in which two faces shared one emotion and two shared another, and asked participants to relocate a central neutral probe face after a blank delay. When considering the emotion of the probed face independently of the co-occurring emotion at encoding, an overall happy benefit was replicated. However, accuracy was modulated by the nonprobed emotion, with a relocation benefit for angry over sad, happy over fearful, and sad over happy faces. These effects did not depend on encoding fixation time, stimulus arousal, perceptual similarity, or response bias. Thus, emotional competition for faces in VSWM is complex and appears to rely on more than simple arousal- or valence-biased mechanisms. We propose a "social value (SV)" account to better explain when and why certain emotions may be prioritized in VSWM. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Optimized electrical transport properties of La0.7Ca0.18Sr0.12MnO3 film by adjusting sintering temperature

Perovskite manganites Lax(Ca1-ySry)1-xMnO3 have conspicuous electrical transport properties used for the application of uncooled bolometers. Thus, considerable attention has paid to the researches on electrical transport properties of Lax(Ca1-ySry)1-xMnO3. Temperature coefficient of resistivity (TCR) and the corresponding peak temperature (Tk) are crucial parameters for uncooled bolometers. Optimal La0.7Ca0.18Sr0.12MnO3 (LCSMO) films with highly oriented growth were prepared on (00l) LaAlO3 substrate at different sintering temperature (Ts) using a facile sol-gel spin coating method. Based on the analysis of microstructure, ionic valence, surface morphology and electrical transport properties, LCSMO films exhibit high crystallinity and large room-temperature TCR at higher Ts. Theoretical Curie temperature and the coupling of the electron lattice weaken gradually with the increase in Ts, which is the dominant factor for the optimization of electrical transport properties. Additionally, the results suggest that the active energy and theoretical Curie temperature play a crucial role in adjusting TCR and Tk. With the increase in Ts, the former increases while the latter decreased, resulting in a high TCR value (12.10%/K) at room temperature (297.38 K). The peak TCR value of LCSMO sintered at 1673 K is about 25% higher than that of the film sintered at 1473 K. The resulting LCSMO films demonstrate great potential for application in uncooled bolometers. Further theoretical basis on the effects of Ts on electrical transport properties was provided.

The Correlation among the Atomic Structure, Electronic Valence Band and Properties of Zr-Cu-Al-Ag Bulk Metallic Glasses

Investigating the relationship between the glass-forming ability (GFA), mechanical properties, and structure of metallic glasses is crucial to understanding the nature of the metallic glass state. In this study, the correlation among the atomic structure, electronic valence band, and properties have been studied using Zr50Cu44.5−xAl5.5Agx (x = 0, 1.5, 3 at.%) bulk metallic glasses (BMGs). The results reveal that through the micro-addition of Ag, the GFA of Zr50Cu44.5Al5.5 BMG can be enhanced; meanwhile, the critical diameter of Zr50Cu44.5Al5.5 glass rods increases from approximately 2.5 mm to 5.0 mm with the addition of 3% Ag. Through the addition of Ag, the thermal stability of Zr50Cu44.5Al5.5 BMG is improved, and the proportion of icosahedral-like clusters increases. The plasticity of the Zr50Cu44.5−xAl5.5Agx (x = 0, 1.5, 3 at.%) BMGs decreased from 4.6% to 0.8% with the addition of Ag. The valence band spectrum of the Zr50Cu44.5−xAl5.5Agx (x = 0, 1.5, 3 at.%) BMGs indicates that with the addition of Ag, the p-d hybridization near the Fermi level is enhanced, and the binding energy will move to a lower value.

Spherical CeO2 synthesized by molten-salt with unique fast variable valence properties for lithium-ion battery anode

As an important rare earth oxide, fluorite CeO2 is widely used in lithium ion batteries because it can quickly and directly change the oxidation state of cerium from Ce3+ to Ce4+. In this work, the ball milling method and the molten salt approach were both used to successfully produce amorphous carbon-coated CeO2 composite. The CeO2@C composite has excellent rate characteristics, high reversibility, and cycling stability. In contrast to the pure CeO2 electrode, the reversible capacity of CeO2@C remains at 264.8 mAh/g after 100 cycles at 100 mA g−1, with a capacity retention rate of 79.3%. The CeO2@C specific capacity is returned to 257.2 mAh/g, accounting for 89% of the initial capacity, after large current fluctuations and returning to the initial current density.

Through Derivational Relations to Valency of Nonverbal Predicates in the Nomvallex Lexicon

Abstract NomVallex is a manually annotated valency lexicon of Czech nouns and adjectives that enables a comparison of valency properties of derivationally related lexical units. We present new developments in how the lexicon facilitates research into changes in valency across part-of-speech categories and derivational types. In particular, it provides links from derived lexical units to their base lexical units and also allows to search and display a base lexical unit together with all lexical units directly derived from it. Using an automatic procedure, any difference in valency between two derivationally related lexical units is specified. As a case study, focusing on nouns and adjectives directly or indirectly motivated by verbs, the facilities provided by the lexicon are used to show differences in what ways the particular deverbal derivatives representing various derivational types express the valency complementation standing in the base verbal construction in the subject position.

Enrichment of adeno-associated virus serotype 5 full capsids by anion exchange chromatography with dual salt elution gradients.

Adeno-associated virus-based gene therapies have demonstrated substantial therapeutic benefit for the treatment of genetic disorders. In manufacturing processes, viral capsids are produced with and without the encapsidated gene of interest. Capsids devoid of the gene of interest, or "empty" capsids, represent a product-related impurity. As a result, a robust and scalable method to enrich full capsids is crucial to provide patients with as much potentially active product as possible. Anion exchange chromatography has emerged as a highly utilized method for full capsid enrichment across many serotypes due to its ease of use, robustness, and scalability. However, achieving sufficient resolution between the full and empty capsids is not trivial. In this work, anion exchange chromatography was used to achieve empty and full capsid resolution for adeno-associated virus serotype 5. A salt gradient screen of multiple salts with varied valency and Hofmeister series properties was performed to determine optimal peak resolution and aggregate reduction. Dual salt effects were evaluated on the same product and process attributes to identify any synergies with the use of mixed ion gradients. The modified process provided as high as ≥75% AAV5 full capsids (≥3-fold enrichment based on the percent full in the feed stream) with near baseline separation of empty capsids and achieved an overall vector genome step yield of >65%.

Construction of Tri‐Functional HOFs Material for Efficient Selective Adsorption and Photodegradation of Bisphenol A and Hydrogen Production

AbstractThis study proposes the construction of porous nanomaterial (HOFs@Fe3+) which anchors non‐noble metal ions Fe3+ onto nanoscale rod‐like hydrogen‐bonded organic frameworks (HOFs) by electrostatic and coordination interactions. The high specific surface area and the abundance of hydrogen‐bond adsorption active sites in pore structure of HOFs@Fe3+ facilitate strong interactions with the double OH in bisphenol A (BPA), resulting in the highest saturation adsorption of BPA that has been reported so far (452 mg g‐1). In addition, the ordered conjugate stacking framework structure and hydrogen bond of HOFs@Fe3+ and the variable valence properties of Fe3+ create new pathways for efficient separation of photogenerated carriers. The results show that HOFs@Fe3+ can completely adsorb and photodegrade 50 ppm BPA within 20 min, owing to the abundant hydrogen bond that acts both as adsorption sites to accelerate the mass transfer process and as catalytic sites to ensure adsorption and photodegradation can be matched synergistically. Meanwhile, the efficiency of photocatalytic H2 production by HOFs@Fe3+ reaches 21.55 mmol g‐1 h‐1 with non‐noble metal Fe3+ as co‐catalyst. This tri‐functional material with high adsorption capacity, high photodegradation efficiency, and high photocatalytic H2 production activity can be successfully used to solve the long‐standing conflict between environment and energy.

Modulating the Catalytic Properties of Bimetallic Atomic Catalysts: Role of Dangling Bonds and Charging.

Bimetallic atomic catalysts (BACs) exhibit great potential in CO2 electroreduction. However, modulation and improvement of their catalytic performance are still challenging. To address these issues, an intrinsic descriptor ψ based on the valence properties of active centers was used. The role of the dangling bonds and charging in modulating the catalytic properties of BACs called M1 M2 -N6 -G (M1 =Ru and Fe) was studied. It was shown that linear relationships between the adsorption energy of the C-species are broken under the effect of the dangling bonds and that they are restored with charging. However, charging has minor effects on the adsorption of the O-species. These findings enable screening promising BACs for CH3 OH production. This research provides effective schemes for modulating the properties of catalysts, which is beneficial to enriching high-performance catalysts for various reactions.