bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Imidazo[1,2-a]pyridine-Based Donor–Acceptor Chromophores through a Multicomponent Approach
Authors: Zysman-Colman Eli , Bräse Stefan , Stahlberger Mareen , Mergel Milada , dos Santos John Marques , Matulaitis Tomas , Nieger Martin
Published: January 2024

A series of donor-acceptor chromophores was synthesized bearing a 3-aminoimidazo[1,2-a]pyridine donor motive. Through DFT calculations, different combinations of the ImPy donor motive and different electron acceptors were assessed. In combination with an anthraquinone acceptor, the calculated ΔE
ST values were in range to suggest that these compounds would emit via thermally activated delayed fluorescence. Based on these findings, a series of ImPy-Aq emitters with different geometries and substitution patterns was synthesized through GBB-3CR and Suzuki coupling reactions. According to preliminary experimental data, the compounds were only slightly emissive at ambient temperatures due to a combination of low radiative rates and competing non-radiative deactivation pathways.
Condensation of Amines with S-Methyl Thiouronium Salts: Another Entry for the Synthesis of Amidines
Authors: Swaroop Toreshettahally R. , Torun Lokman , Bakyyev Rahym , Rangappa Kanchugarakoppal S.
Published: January 2024

We present a condensation of primary aryl or alkyl amines with S-methyl thiouronium salts to obtain N,N,N′-trisubstituted amidines. High yields, short reaction times, and a fair substrate scope are the noteworthy features of this protocol. Surprisingly, the reaction of a thiouronium salt with 4-aminopyridine gave 1-(4-methoxybenzoyl)piperidine.
Sultines as o-Quinodimethane Precursors in an Oxa-Diels–Alder Reaction: Synthesis of Functionalized Isochromans
Authors: Ngamnithiporn Aurapat , Chuentragool Padon , Songthammawat Poramate , Punnita Supakarn , Photong Kittithuch , Ploypradith Poonsakdi , Ruchirawat Somsak
Published: January 2024

The development of an oxa-Diels–Alder reaction between sultines and carbonyl compounds is reported. o-Quinodimethanes, generated from sultines, undergo a [4+2]-cycloaddition with activated aldehydes or ketones in the presence of Cu(OTf)2 to provide a variety of functionalized isochromans, including spiroisochromans, in up to 99% yield. The developed protocol demonstrates broad functional-group compatibility and tolerates unprotected isatins bearing free NH-functionalities.
Linear and nonlinear relationships between instructional leadership and teacher professional learning through teacher self-efficacy as a mediator: a partial least squares analysis
Authors: Thien Lei Mee , Liu Peng
Published: January 2024

Although the investigation of instructional leadership and teacher professional learning is well-documented in the literature, one overlooked question concerns the linear and nonlinear relationships between these two variables. This study aims to examine the linear and nonlinear relationships of principal instructional leadership on teacher professional learning through teacher self-efficacy as a mediator. This study has collected 335 teacher samples encompassing both primary and secondary school levels in Penang, Malaysia. The analysis of data utilised partial least-squares structural equation modelling. The findings indicated a significant positive linear relationship between instructional leadership and teacher-professional learning. Likewise, there exists a significant mediating effect of teacher self-efficacy between instructional leadership on teacher professional learning. There exists a significant nonlinear relationship between principal instructional leadership on teacher self-efficacy and teacher professional learning respectively. The structural model exhibits a significantly high level of predictive power for in-sample and out-of-sample. This study offers theoretical and methodological advancements in comprehending the complex relationships between instructional leadership and teacher outcomes. It proposes that forthcoming studies could adopt a combination of linear and non-linear relationships to achieve robust empirical findings.
Community-based management for low-digitalized communities using cross-cutting purchasing behavior
Authors: Ieiri Yuya , Yamaki Kaishu , Hishiyama Reiko
Published: January 2024

The need for community-based management to revitalize the economy of commercial areas by using consumer behavior analysis focusing on transactions has increased. Low-digitalized shopping communities, commercial communities that include retailing that have not introduced digital technologies, require community-based management using consumer behavior analysis. However, low-digitalized shopping communities cannot collect cross-cutting consumer behavior data using digital technologies such as point of sales (POS) systems. This difficulty obscures the novel management potential of applying such customer behavior analysis to community-based management. Our study aims to bridge the gap between low-digitalized shopping communities and community-based management using customer behavior analysis. To achieve this purpose, this study proposed a novel management approach using data collected using paper-based community currencies and its analysis method. Two field experiments were performed in low-digitalized shopping communities in Japan using two types of community currencies: from-to (FT) and customer attributes (CA). This study illustrated the possibility of community-based management in low-digitalized shopping communities and extending conventional retailing management methods using customer behavior analysis to community-based management.
The persuasive power of social media influencers in brand credibility and purchase intention
Authors: Liu Xiao , Zheng Xiaoyong
Published: January 2024

The use of social media influencer collaboration is growing exponentially. This study explores the persuasive power of influencers on followers’ perceived brand credibility and purchase intention by applying the elaboration likelihood model of persuasion. The results show that the informative value of influencers’ content, authenticity, and homophily positively affect their parasocial relationships, which in turn, affects followers’ purchase intention and evaluation of brand credibility. Followers’ persuasion knowledge negatively moderates the relationship between parasocial relationships and followers’ perceived brand credibility; it has no moderating effect on the relationship between parasocial relationships and followers’ purchase intention.
Simulation of population size and economic scale supportable by the Yellow River’s available freshwater in 2030 under multiple scenarios
Authors: Guo Lishuo , Song Xiaogang , Wang Qi
Published: January 2024

The Yellow River plays a crucial role in China’s socioeconomic development and ecological security. The amount of freshwater available for allocation to the nine provinces of the Yellow River basin (YRB) is expected to be 39.485 billion m3 in 2030, for a projected population of 0.13094 billion people. This study aimed to simulate the sustainable population size and economic scale attainable with the Yellow River’s restricted freshwater supply. We forecasted population size and economic scale under various scenarios using a water resource carrying capacity (WRCC) prediction model. Further, the most likely scenarios—high, moderate, and low development—were analyzed based on historical trends. The results showed that by 2030, the available freshwater could support population sizes of 0.16, 0.152, and 0.147 billion under the high-, moderate-, and low-development scenarios, respectively, all of which are greater than 0.13094 billion. Moreover, economic scales of CNY17.5 trillion ($2.52 trillion), CNY15.01 trillion ($2.18 trillion), and CNY13.2 trillion ($1.91 trillion) could be supported under the high-, moderate-, and low-development scenarios, respectively. This study’s contributions are that (1) using population size and economic scale to characterize WRCC overcomes the limitation of measuring WRCC with a dimensionless index; (2) quantifying WRCC overcomes the flaws of single-trend measurement; and (3) the scenarios paint a clear picture of the YRB’s future water security and socioeconomic development. Our findings could help steer the direction of future water-, population-, and economy-related policymaking.
Does learning ambidexterity affect the sense of urban integration among new-generation migrant workers in China? An empirical study based on career growth and environmental dynamism
Authors: Zheng Ai-xiang
Published: January 2024

The urban integration of new-generation migrant workers is an important part of the process of new urbanization in China, and the acquisition of a sense of urban integration is one of the necessary signs of urban integration for new-generation migrant workers. Based on ambidexterity theory, we used a multiple regression analysis to study the mechanism underlying the effects of learning ambidexterity on the sense of urban integration of new-generation migrant workers. The empirical results showed that learning ambidexterity had significant and positive effects on both sense of urban integration and career growth; career growth had a partial mediating effect on the relationship between learning ambidexterity and sense of urban integration; environmental dynamism had a positive moderating effect on the relationship between exploratory learning and career growth; and environmental dynamism had a positive moderating effect on the relationship between exploitative learning and sense of urban integration. This study responds to previous research on the ambidexterity of migrant workers and further enriches the ambidexterity theory in research on migrant workers from the perspectives of career growth and urban integration. And in contrast to earlier studies, this research introduces environmental dynamism and establishes an analysis framework for migrant worker urban integration in a dynamic environment.
Online sharing behaviors driven by need for approval: the choice of individuals with low social intelligence and high gratitude?
Authors: Nie Ting , Gui Yanli , Huang Yiying
Published: January 2024

Knowledge sharing as an altruistic behavior has gained widespread attention. In the information age, online sharing is increasingly popular and has become an important way of exchanging and stimulating knowledge. Through a survey of 458 employees in China, this study examines the influence mechanism of need for approval on individual online sharing behavior and the moderating effect of gratitude and social intelligence. Study findings show that self-presentation has a mediating effect between need for approval and online sharing behavior, and individual need for approval can promote online sharing behavior by enhancing self-presentation. Gratitude and social intelligence both have positive moderating effects on the relations between self-presentation and online sharing behavior. Gratitude moderates the indirect influence of need for approval on online sharing behavior through self-presentation. Individuals with high gratitude and high social intelligence at the same time can strengthen the positive effect of self-presentation on online sharing behavior. Individuals can meet their approval need and obtain learning opportunities through online sharing behaviors. Organizations can select talents and obtain valuable information by establishing sharing platforms. Governments should also regulate online platforms for knowledge exchange as well as encourage individual online sharing behaviors.
“Listening to the zoom of a hornet”: Virginia Woolf’s feminist reflections on the sounds of military weapons and war violence
Authors: Zhu Haifeng , Ding Hui , Chen Weiyu
Published: January 2024

In her diaries, novels, and essays, Virginia Woolf records the psychological trauma the British people suffered from in the soundscape of military weapons during the two world wars and describes its delayed effects on the populace after the wars. Drawing upon the notions of the soundscape and Johan Galtung’s violence triangle, this paper explores how Woolf’s works portray the traumatic experience brought by the soundscape of military weapons to soldiers and ordinary citizens during the two world wars and discusses how the roar of cars and planes in her works induces the public’s traumatic memory after the wars. Then, through a close study of her essay “Thoughts on Peace in an Air Raid”, this paper contends that the soundscape of German air raids compels Woolf to contemplate the roles of feminism in opposing the wars and healing war trauma.
Simulation and fabrication of in vitro microfluidic microelectrode array chip for patterned culture and electrophysiological detection of neurons
Authors: Yang Yan , Xu Shihong , Deng Yu , Liu Yaoyao , Zhang Kui , Lv Shiya , Sha Longze , Xu Qi , Cai Xinxia , Luo Jinping
Published: January 2024

To enable the detection and modulation of modularized neural networks in vitro, this study proposes a microfluidic microelectrode array chip for the cultivation, compartmentalization, and control of neural cells. The chip was designed based on the specific structure of neurons and the requirements for detection and modulation. Finite-element analysis of the chip’s flow field was conducted using the COMSOL Multiphysics software, and the simulation results show that the liquid within the chip can flow smoothly, ensuring stable flow fields that facilitate the uniform growth of neurons within the microfluidic channels. By employing MEMS technology in combination with nanomaterial modification techniques, the microfluidic microelectrode array chip was fabricated successfully. Primary hippocampal neurons were cultured on the chip, forming a well-defined neural network. Spontaneous electrical activity of the detected neurons was recorded, exhibiting a 23.7% increase in amplitude compared to neuronal discharges detected on an open-field microelectrode array. This study provides a platform for the precise detection and modulation of patterned neuronal growth in vitro, potentially serving as a novel tool in neuroscience research.
Two-dimensional Rashba superconductivity in Ni/Bi bilayers evidenced by nonreciprocal transport
Authors: Hayashi Hiroki , Ando Kazuya
Published: January 2024

When two different materials are brought together, a plethora of quantum phenomena and functionalities can emerge. A prominent example is the superconductivity in Ni/Bi bilayers, which arises from the artificial layered structure composed of the non-superconducting ferromagnetic and heavy metals. Although this system has been shown to exhibit unconventional superconducting properties, the underlying mechanism of the superconductivity remains elusive. Here, we provide experimental evidence of the microscopic coexistence of two-dimensional (2D) superconductivity and broken space-inversion symmetry in the Ni/Bi bilayer. The evidence is obtained from nonreciprocal transport around the superconducting transition temperature, where the resistance depends on the direction of an applied current and an external magnetic field. We find that the nonreciprocal superconducting transport is most pronounced around the Berezinskii–Kosterlitz–Thouless transition temperature. These observations support the 2D Rashba superconductivity in the Ni/Bi bilayer, which will serve as a basis for advancing the understanding of unconventional superconductivity.
Global stability of supersonic Euler flows in quasi-one-dimensional convergent nozzles
Authors: Liao Jing , Tan Zhong
Published: January 2024

In this paper, we investigate the global well-posedness and stability of steady supersonic Euler flows in a quasi-one-dimensional convergent nozzle. First, we show that there exists a critical nozzle length L1, the global well-posedness of steady supersonic flows can be obtained and the explicit solution is given as long as the nozzle length L < L1. Then we prove the global stability of steady supersonic flows under small perturbations of initial-boundary values by wave decomposition.
Solvent-mediated modification of thermodynamics and kinetics of monoethanolamine regeneration reaction in amine-stripping carbon capture: Computational chemistry study
Authors: Afify N. D. , Sweatman M. B.
Published: January 2024

A major limitation of amine-based post-combustion carbon capture technology is the necessity to regenerate amines at high temperatures, which dramatically increases operating costs. This paper concludes the effect of solvent choice as a possible route to modify the thermodynamics and kinetics characterizing the involved amine regeneration reactions and discusses whether these modifications can be economically beneficial. We report experimentally benchmarked computational chemistry calculations of monoethanolamine regeneration reactions employing aqueous and non-aqueous solvents with a wide range of dielectric constants. Unlike previous studies, our improved computational chemistry framework could accurately reproduce the right experimental activation energy of zwitterion formation. From the thermodynamics and kinetics of the predicted reactions, the use of non-aqueous solvents with small dielectric constants led to reductions in regeneration Gibbs free energies, activation barriers, and enthalpy changes. This can reduce energy consumption and give an opportunity to run desorption columns at relatively lower temperatures, thus offering the possibility of relying on low-grade waste heat as an energy input.
Solving the Orszag–Tang vortex magnetohydrodynamics problem with physics-constrained convolutional neural networks
Authors: Bormanis A. , Leon C. A. , Scheinker A.
Published: January 2024

We study the 2D Orszag–Tang vortex magnetohydrodynamics (MHD) problem through the use of physics-constrained convolutional neural networks (PCNNs) for forecasting the density, ρ, and the magnetic field, B, as well as the prediction of B given the velocity field v of the fluid. In addition to translation equivariance from the convolutional architecture, other physics constraints were embedded: absence of magnetic monopoles, non-negativity of ρ, use of only relevant variables, and the periodic boundary conditions of the problem. The use of only relevant variables and the hard constraint of non-negative ρ were found to facilitate learning greatly. The divergenceless condition ∇·B=0 was implemented as a hard constraint up to machine precision through the use of a magnetic potential to define B=∇×A. Residual networks and data augmentation were also used to improve performance. This allowed for some of the residual models to function as surrogate models and provide reasonably accurate simulations. For the prediction task, the PCNNs were evaluated against a physics-informed neural network, which had the ideal MHD induction equation as a soft constraint. Several models were able to generate highly accurate fields, which are visually almost indistinguishable and have low mean squared error. Only methods with built-in hard constraints produced physical fields with ∇·B=0. The use of PCNNs for MHD has the potential to produce physically consistent real-time simulations to serve as virtual diagnostics in cases where inferences must be made with limited observables.
Realization of fast-speed and low-power phase change memory by optimizing Ge10Sb90 film with samarium doping
Authors: Gu Han , Wu Weihua , Zhou Xiaochen , Zhang Pei , Fu Bowen , Zhu Xiaoqin , Song Sannian , Song Zhitang
Published: January 2024

In this paper, the Sm-doped Ge10Sb90 films were proposed and the effect of Sm doping on the crystal structure and electrical properties were investigated. The crystallization process of materials with different Sm concentrations was carried out by an in situ resistance measurement system, demonstrating that doping Sm can significantly improve the amorphous resistance, thermal stability, and bandgap of Ge10Sb90 film and alleviate the structural relaxation. X-ray diffraction, x-ray photoelectron spectroscopy, and transmission electron microscopy show that the appropriate content of Sm doping can hinder the grain growth process, limiting the grain size to a certain extent. The phase change memory devices with Sm-doped Ge10Sb90 were prepared based on the CMOS process, and their electrical properties were evaluated. The outcomes indicate that Sm doping can remarkably ameliorate the high RESET current required for Sb-rich Ge10Sb90 films during erasing/writing operation.
Field-free magnetic switching dependence on lateral interfaces in synthetic antiferromagnets by ion implantation
Authors: Shen Bowen , Yang Meiyin , Li Yanru , Yu Peiyue , Gao Jianfeng , Cui Baoshan , Yu Guoqiang , Luo Jun
Published: January 2024

Field-free spin–orbit torque switching in synthetic antiferromagnets (SAF) holds significant promise for high-density spintronic memory and logic devices. In this paper, we realize the field-free magnetization switching in SAFs due to the local ion implantation-induced 45° lateral interface and symmetry breaking. Moreover, the magnetization switching ratio is enlarged by the lateral interface owing to the superimposition of a damping-like effective field and a symmetry-breaking effective field. Our work is significant for the development of magnetic random-access memory technology with high-speed and anti-interference ability.
Giant static refractive index gradient induced by strong ultrasonic wave
Authors: Harada Yuki , Ishikawa Mutsuo , Kuroda Yuma , Matsukawa Mami , Koyama Daisuke
Published: January 2024

Spatiotemporal modulation of refractive index in an optical path medium allows for control of light propagation. This refractive index change (Δn) can be achieved by external stimulation such as temperature or density change, but there is a limit to the extent to which Δn can be controlled by external stimulation acting on a single medium. Here, we demonstrate a technique to form a giant refractive index gradient (Δn = 0.06) in a small region of water (< 10 mm) using a high-frequency, high-intensity (in the 100-megahertz-range, on the order of megapascals) ultrasonic wave. Ultrasonic radiation in water can statically modulate the refractive index in water from the initial value (n = 1.33) toward that of air.
Unravelling the doping mechanism and origin of carrier limitation in Ti-doped In2O3 films
Authors: Emmerich Ann-Katrin , Creutz Kim Alexander , Cheng Yaw-Yeu , Jaud Jean-Christophe , Hubmann Andreas , Klein Andreas
Published: January 2024

Ti-doped In2O3 thin films with varying Ti contents are prepared by partial reactive co-sputtering using ceramic In2O3 and metallic Ti targets and characterized by in situ x-ray photoelectron spectroscopy, electrical conductivity, and Hall-effect measurements. For a substrate temperature of 400°C, the carrier concentration increases faster than the Ti content and saturates at ≈7.4×1020cm−3. Based on these results, it is suggested that Ti does not directly act as donor in In2O3 but is rather forming TiO2 precipitates and that the related scavenging of oxygen generates oxygen vacancies in In2O3 as origin of doping. Neutralization of oxygen vacancies is, therefore, suggested to be origin of the limitation of the carrier concentration in Ti-doped In2O3 films.
Grain size and lattice compatibility enhanced figure-of-merit in Ba0.95Ca0.05Ce0.005ZrxTi0.995−xO3 material for pyroelectric energy conversion
Authors: Huang Ruhao , Zhu Zeyuan , Geng Ruiheng , Chan Ka Hung , Chen Xian , Zhang Chenbo
Published: January 2024

Phase-transforming ferroelectric materials have attracted significant attention due to their potential for energy conversion from waste heat. Here, we explore the impact of grain size and lattice compatibility on the energy conversion figure-of-merit (FOM) of a phase-transforming ferroelectric system Ba0.95Ca0.05Ce0.005ZrxTi0.995−xO3 with Zr content ranging from 0.004 to 0.03. The results demonstrate that tuning grain size and lattice compatibility can significantly increase the FOM. The optimal composition Zr0.006 exhibits the highest FOM among its neighboring compositions, with a corresponding peak pyroelectric current density of 5.6 μA/cm2 generated from a temperature fluctuation of 30 °C at a temperature rate of 5 °C/s. This work provides a rational understanding of the effect of grain morphology and crystal structure on the pyroelectric properties for energy conversion.
Fine structures of intrinsically disordered proteins
Authors: Seth Swarnadeep , Stine Brandon , Bhattacharya Aniket
Published: January 2024

We report simulation studies of 33 single intrinsically disordered proteins (IDPs) using coarse-grained bead-spring models where interactions among different amino acids are introduced through a hydropathy matrix and additional screened Coulomb interaction for the charged amino acid beads. Our simulation studies of two different hydropathy scales (HPS1, HPS2) [Dignon et al., PLoS Comput. Biol. 14, e1005941 (2018); Tesei et al. Proc. Natl. Acad. Sci. U. S. A. 118, e2111696118 (2021)] and the comparison with the existing experimental data indicate an optimal interaction parameter ϵ = 0.1 and 0.2 kcal/mol for the HPS1 and HPS2 hydropathy scales. We use these best-fit parameters to investigate both the universal aspects as well as the fine structures of the individual IDPs by introducing additional characteristics. (i) First, we investigate the polymer-specific scaling relations of the IDPs in comparison to the universal scaling relations [Bair et al., J. Chem. Phys. 158, 204902 (2023)] for the homopolymers. By studying the scaled end-to-end distances ⟨RN2⟩/(2Lℓp) and the scaled transverse fluctuations l̃⊥2=⟨l⊥2⟩/L, we demonstrate that IDPs are broadly characterized with a Flory exponent of ν ≃ 0.56 with the conclusion that conformations of the IDPs interpolate between Gaussian and self-avoiding random walk chains. Then, we introduce (ii) Wilson charge index (W) that captures the essential features of charge interactions and distribution in the sequence space and (iii) a skewness index (S) that captures the finer shape variation of the gyration radii distributions as a function of the net charge per residue and charge asymmetry parameter. Finally, our study of the (iv) variation of ⟨Rg⟩ as a function of salt concentration provides another important metric to bring out finer characteristics of the IDPs, which may carry relevant information for the origin of life.
Twisted oxide membranes: A perspective
Authors: Pryds N. , Park D.-S. , Jespersen T. S. , Yun S.
Published: January 2024

Freestanding oxide membranes have recently emerged as a promising platform, offering new opportunities for experimentalists to design materials with novel properties. These membranes, typically consisting of transition metal oxides, can be synthesized as freestanding ultra-thin quasi-2D layers and, subsequently, reassembled into multilayer stacks with controlled relative twist angles. In these heterostructures, controlling the moiré superlattices pattern of the two lattices can play a crucial role in creating unique and new electronic, optical, magnetic, and mechanical properties that do not exist in the individual constituent materials or in traditional non-twisted epitaxial heterostructures. Here, we explore the role of stacking and twisting of freestanding oxide membranes, including the underlying principles and potential applications. We also discuss the current challenges and provide a perspective on some of the possible future directions of the field. Our aim is to highlight the opportunities for creating new functional materials by stacking and twisting freestanding oxide membranes.
Experimental investigation about the aerodynamic noise caused by hypersonic turbulence
Authors: Liu Xiaolin , Yi Shihe
Published: January 2024

In this study, experimental investigations pertaining to aerodynamic noise are conducted in a hypersonic quiet wind tunnel, which possesses the unique capability of operating in both quiet and conventional modes, achieved by controlling the bleed slot to regulate the boundary layer flow. The measurement of aerodynamic noise and analysis of coherent structures of hypersonic turbulence are accomplished employing pressure probes and the nano-tracer-based planar laser scattering technique. The characterization of aerodynamic noise within the freestream unveils that noise generated by turbulent structures on the nozzle wall is the primary factor affecting the turbulence intensity of the freestream flow. Regarding the acoustic radiation noise generated by the turbulence on the nozzle wall, a peak frequency ranging from 54 to 57 kHz is observed in its spectrum within a unit Reynolds number range of 0.3×107–1.1×107 m−1. Under different operation modes, the freestream pitot-pressure data feature the similar spectral slope of f−2.2 and f−12 before and after the aforementioned peak. Through wavelet analysis, scales of the coherent structure in the turbulent boundary layer are examined, revealing that the maximum energy streamwise scale of the coherent structure is approximately 2.47 mm under the unit Reynolds number of 0.7×107 m−1. The product of this scale with the characteristic frequency of 56 kHz obtained from fluctuating pressure measurements is close to the local sound speed of about 140 m/s.
Bond length alternation of π-conjugated polymers predicted by the Fermi–Löwdin orbital self-interaction correction method
Authors: Nguyen Duyen B. , Jackson Koblar A. , Peralta Juan E.
Published: January 2024

π-conjugated polymers have been used in a wide range of practical applications, partly due to their unique properties that originate in the delocalization of electrons through the polymer backbone. The level of delocalization can be characterized by the induced bond length alternation (BLA), with shorter BLA connected with strong delocalization and vice versa. The accurate description of this structural parameter can be considered a benchmark for testing the capability of different electronic structure methods for self-interaction error (SIE) removal and electron correlation inclusion. Density functional theory (DFT), in its local or semi-local flavors, suffers from SIE and, thus, underestimates the BLA compared to self-interaction-free methods. In this work, we utilize the Fermi–Löwdin orbital self-interaction correction (FLOSIC) method for one-electron self-interaction removal to characterize the BLA of five oligomers with increasing length extrapolated to the polymeric limit. We compare the self-interaction-free BLA to several DFT approximations, Møller–Plesset second-order perturbation theory (MP2), and the BLA obtained with the domain based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] approximation. Our findings show that FLOSIC corrects for the small BLA given by (semi-)local DFT approximations, but it tends to overcorrect with respect to CAM-B3LYP, MP2, and DLPNO-CCSD(T).
Bidisperse micro fluidized beds: Effect of bed inclination on mixing
Authors: Oliveira Henrique B. , Franklin Erick M.
Published: January 2024

Micro fluidized beds are basically suspensions of solid particles by an ascending fluid in a millimeter-scale tube, with applications in chemical and pharmaceutical processes involving powders. Although in many applications beds are polydisperse, previous works considered only monodisperse beds aligned in the vertical direction. However, introducing an inclination with respect to gravity leads to different bed patterns and mixing levels, which can be beneficial for some applications. In this paper, we investigate experimentally the behavior of micro gas–solid beds consisting of bidisperse mixtures under different inclinations. In our experiments, mono- and bidisperse beds are filmed with a high-speed camera, and the images are processed for obtaining measurements at both the bed and grain scales. We show that the degree of segregation is larger for vertical beds, but mixing varies non-monotonically with inclination, with an optimal angle of 30°–50° with respect to gravity. By computing the mean and fluctuation velocities of grains, we reveal that the mixing layer results from the competition between segregation by kinetic sieving and circulation promoted by the fluid flow. We also observe worse fluidization as the angle relative to gravity increases, accounting then for the non-monotonic behavior. Our results bring new insights into mixing and segregation in polydisperse beds, which can be explored for processing powders in industry.
Green-emitting cubic GaN/In0.16Ga0.84N/GaN quantum well with 32% internal quantum efficiency at room temperature
Authors: Lee J. , Bayram C.
Published: January 2024

Structural and optical properties of a green-emitting cubic (i.e., zinc blende) GaN/In0.16Ga0.84N/GaN single quantum well structure are reported. The active layer is grown on a phase-pure (i.e., 100%) cubic GaN enabled on a 1 × 1 cm2 U-grooved silicon (100) through aspect ratio phase trapping. Energy dispersive x-ray spectroscopy combined with room temperature cathodoluminescence reveals 522 nm green light emission at room temperature with only 16.0% ± 1.6% of indium content, which is ∼30% less than the amount of indium needed in a traditional green-emitting hexagonal (i.e., wurtzite) well. Temperature-dependent behavior of the green emission, such as activation energy, s-shaped peak energy shift, and linewidth, is reported. Cathodoluminescence at 8 and 300 K reveals an internal quantum efficiency of 32.0% ± 0.6%, which is higher than any reported value for cubic wells. Overall, phase-pure cubic active layers on phase transition cubic GaN are shown to be promising for green and longer wavelength emitters.
Oxygen vacancies stabilized 180° charged domain walls in ferroelectric hafnium oxide
Authors: Xu Zhongshan , Zhu Xiaona , Zhao Guo-Dong , Zhang David Wei , Yu Shaofeng
Published: January 2024

Ferroelectric domain walls (DWs) are spatial interfaces separating domains with distinct polarization orientations. Among these DWs, some can carry bound charges and display metallic-like conductivity. The feature is highly of interest for future nanoelectronics. However, the inherent instability of charged domain walls (CDWs) has posed a critical challenge for their experimental exploration. This Letter reports the head-to-head (HH) and tail-to-tail (TT) 180° CDWs within the context of ferroelectric hafnium oxide. We proposed that oxygen vacancy is a crucial factor stabilizing the periodic CDWs. Through meticulous first-principles calculations, we elaborated on the intricate properties of these CDWs, including their polarization profiles, and potential and charge distributions. Furthermore, we calculated the energy barrier for layer-by-layer propagation of a HH wall and carefully discussed the migration of a TT wall with oxygen vacancy. Our study can shed more light onto the characteristics of CDWs and their implications to hafnia-based ferroelectric devices.
Impingement of a water droplet onto a rotational surface
Authors: Zhou Yi , Jin Zheyan , Yang Zhigang
Published: January 2024

In the present study, the impact of a water droplet onto a rotational surface was experimentally studied. The effects of the impact velocity, the rotational speed, and the impact radial position on the impact phenomena were carefully investigated. The phenomena of asymmetric spreading, finger formation, and secondary droplets were observed. Moreover, experiments of a water droplet impacting onto a stationary surface with different impact velocities were also conducted for comparisons. The results showed that, at the same impact velocity, the increase in the rotational speed or the impact radial position could result in the increase in the wetting length in the angular direction and the wetting area. In addition, at the same impact velocity, the dimensionless wetting length in the radial direction on the rotational surface was generally lower than the spreading factor on the stationary surface. In addition, new correlations for the spreading ratio, the dimensionless excess spread area, the dimensionless maximum wetting area, and the number of fingers appearing at the angle of 50° after impact were proposed. The increase in the impact velocity and the surface linear velocity could both promote the formation of the fingers at the angle of 50° after impact. In addition, the dimensionless horizontal displacement of the secondary droplet was found to be mainly influenced by the impact velocity, while the surface linear velocity only had a minor influence.
Experimental quantification of ion flux reduction at the sheath edge due to ion–neutral collisions in low temperature plasmas
Authors: Lim Yegeon , Ghim Young-chul
Published: January 2024

Reduction of the ion flux at the sheath edge due to ion–neutral collisions in low temperature DC plasmas is experimentally quantified for low to intermediate neutral gas pressures (<102 mTorr). The reduction factor is defined as a ratio of the ion flux at the sheath edge in a collisional plasma to that in a collisionless limit in this work. Its quantification as a function of the collisionality with a Langmuir probe has been hindered since the measured data contain two intermingled effects, namely, the flux reduction and the sheath expansion, which are difficult to isolate one from the other. The sheath expansion effect with and without the flux reduction effect are analyzed, and by comparing the two, the reduction factor as a function of the collisionality has been estimated with Langmuir probe data from approximately 1000 systematic scans of the plasma conditions. Neutral gas pressures ranging from 0.2–30.0 mTorr for Ar and 1.0–65.0 mTorr for He discharges are generated in a multidipole chamber with hot filaments. The estimated reduction factors are found to agree with the results from the particle-in-cell simulations for He discharges [Beving et al., Plasma Sources Sci. Technol. 31, 084009 (2022)]. The estimated reduction factors for Ar discharges are larger than those for He discharges, and the dependence of the reduction factor on species is discussed. Reduction of the ion flux at the sheath edge at intermediate gas pressures highlights the importance of taking into account ion–neutral collisions in many plasma applications.
Directional emission in an on-chip acoustic waveguide
Authors: Hirsch T. M. F. , Mauranyapin N. P. , Romero E. , Jin X. , Harris G. , Baker C. G. , Bowen W. P.
Published: January 2024

Integrated acoustic circuits leverage guided acoustic waves for applications ranging from radio frequency filters to quantum state transfer, biochemical sensing, and nanomechanical computing. In many applications, it is desirable to have a method for unidirectional acoustic wave emission. In this work, we demonstrate directional emission in an integrated single-mode, on-chip membrane waveguide, demonstrating over 99.9% directional suppression and reconfigurable directionality. This avoids both loss and unwanted crosstalk, allowing the creation of more complex and compact phononic circuits.
Photodissociation of CO2 via the 1Πg state: Wavelength-dependent imaging studies of O(1D2) photoproducts
Authors: Liu Qian , Gao Qinghua , Liu Peng , Yang Xueming , Yu Shengrui
Published: January 2024

Photodissociation of CO2 via the 1Πg state is investigated using a time-sliced velocity-mapped ion imaging apparatus combined with a tunable vacuum ultraviolet photolysis source. The main O(1D2) + CO(X1Σ+) channel is directly observed from the measured images of O(1D2) photoproducts at 129.08–134.76 nm. The total kinetic energy release spectra determined based on these images show that the energetic thresholds for the O(1D2) + CO(X1Σ+) photoproducts correspond to the thermochemical thresholds for the photodissociation of CO2(v2 = 0) and CO2(v2 = 1). One significant difference among the CO(X1Σ+, v) vibrational distributions for the predominant CO2(v2 = 0) dissociation is that the population of CO(v = 0) becomes favorable at 130.23–133.45 nm compared to the Boltzmann-like component (v > 0) that always exists at 129.08–134.76 nm. The wavelength dependences of the overall β are found to follow the variation trend of the CO(v = 0) abnormal intensity. The vibrational state-specific β values present a roughly decreasing trend with an increase in v, whereas β(v = 0) appears to be significantly larger than β(v = 1) at 130.23–133.45 nm compared to 134.76 and 129.08 nm. The non-statistical CO(v = 0) with larger β values at 130.23–133.45 nm implies that an additional pathway may open through the conical intersection coupling to the dissociative 21A′  state, except for the ever-existing pathway that yields the Boltzmann-like component. In contrast, at 129.08 nm, the restoration of the statistical equilibrium in the CO(X1Σ+, v) vibrational distribution may be caused by the emergence of novel dissociation pathways arising from the participation of the 31A″ state.
Influence of tip clearance on internal energy loss characteristics of axial flow pumps under different operating conditions
Authors: Jia XiaoQi , Shen ShengJi , Zhang ShuaiKang , Lv Hao , Lin Zhe , Zhu ZuChao
Published: January 2024

Axial flow pumps possess a unique structure where there must be clearances between the impeller and the piping wall, usually not exceeding 0.1% of the impeller diameter. Despite the small size of the clearance, the internal micro-vortex structures have a non-negligible impact on the main flow field of the impeller. Under the action of the pressure difference between the suction and pressure surfaces of blades, some fluids form high-energy jets in the tip clearance area, known as tip leakage vortices (TLVs). TLV interacts with the flow of the main flow field, exerting a significant impact on the internal flow state, energy loss, and hydraulic performance of the pump. To identify the influence of TLVs on the internal flow field and energy loss of axial flow pumps, this work uses a modified partially averaged Navier–Stokes (PANS) model to perform full flow field numerical calculations for a certain axial flow pump and conducts a comparative analysis of the internal flow field energy dissipation, unsteady vortex structures, energy loss, and other characteristics under three different tip clearances: 0.2 mm (0.05%D), 0.6 mm (0.15%D), and 1.0 mm (0.25%D) based on the energy transport theory. The results indicate that at optimal operating conditions, the internal energy distribution of the fluid in each flow passage is uniform, and the energy loss is primarily caused by axial backflow in the tip area; under critical rotating stall conditions, clearance size affects the distribution state of enstrophy in the guide vane flow passage, leading to average enstrophy being highest at the rim area and the most uneven distribution of enstrophy, inducing larger energy loss in the impeller; during deep stall conditions, the unevenness of internal energy distribution is stronger than that under critical stall conditions, but the overall energy loss within the impeller flow area is lower than that under critical stall conditions, while energy unevenness is mitigated as the tip clearance size increases.
Concentrated “ionogel-in-ceramic” and “ionogel-in-polymer” bilayer electrolyte membrane for high-voltage quasi-solid-state lithium metal batteries
Authors: Chen Zongyuan , Wei Fengkun , Wang Shengxian , Zhai Yanfang , Hu Ning , Song Shufeng
Published: January 2024

A crucial challenge for next-generation batteries depends on development of ideal electrolyte that is expected to demonstrate peculiarity of free-standing membrane with superior conductivity and controlled thickness, along with interface compatibility toward both Li metal anode and high-voltage cathodes. We describe a unique concentrated bilayer electrolyte membrane and validate an electrolyte design strategy based on the integration of ionogel-in-ceramic layer (∼30 μm) and ionogel-in-polymer layer (∼7 μm) that establishes well-percolated Li+ transport and tackles interface issues to address the requirements for electrolyte. The concentrated bilayer electrolyte membrane shows a superior ionic conductivity of 8 × 10−4 S cm−1 at 25 °C, pretty low electronic conductivity of 2.69 × 10−11 S cm−1, and wide electrochemical stability window of 5.5 V vs Li/Li+. It is revealed that the electrolyte membrane enhances Coulombic efficiency to ∼92%, which is ascribed to flat Li plating/stripping and mixed-lithiophobic-conductive LiF-Li3N solid electrolyte interphase. Application of the electrolyte membrane in LiǁLiNi0.8Co0.1Mn0.1O2 quasi-solid-state lithium metal batteries further demonstrates improved cycling performance. Our study, therefore, provides an alternative electrolyte design strategy and a promising electrolyte membrane for high-energy-density quasi-/solid-state batteries.
Fourfold anisotropic magnetic damping induced by anisotropic spin absorption in amorphous CoFeB/epitaxial IrMn3 bilayers
Authors: Wang Yangping , Feng Xinwei , Yan Ze , Xue Kelei , Zhu Xiaoyan , Zhan Qingfeng
Published: January 2024

Magnetic damping rooted in various relaxation processes of spin angular momentum plays a crucial role in determining the energy consumption and the operating speed of emerging spintronic devices. Here, we reported a fourfold anisotropic magnetic damping extrinsically caused by spin current absorption in amorphous ferromagnetic/antiferromagnetic bilayers. The angular dependent broadband ferromagnetic resonance measurements were employed to investigate the effect of interfacial exchange coupling on magnetization dynamics of the CoFeB/IrMn3 bilayers. In addition to the conventional exchange bias, the amorphous CoFeB layer exhibits an induced fourfold magnetic anisotropy along the IrMn3⟨100⟩ axes because of the exchange coupling with the uncompensated IrMn3 moments along IrMn3⟨100⟩ caused by the 3Q antiferromagnetic structure. The magnetic damping of the CoFeB/IrMn3 bilayer also exhibits an obvious fourfold symmetry, which is ascribed to the anisotropic spin absorption caused by the uncompensated IrMn3 moments. The ratio of the fourfold anisotropic magnetic damping decreases dramatically with reducing the interfacial exchange coupling. When the interfacial exchange coupling is isolated by a Cu spacer layer, both the induced magnetic anisotropy and the magnetic damping exhibit a uniaxial symmetry.
On the inverse problem of capillary imbibition through nonuniform axial geometry
Authors: Hayek Mohamed
Published: January 2024

We investigate the inverse problem of capillary imbibition, which consists in determining capillary radius from measurements of imbibition kinematics. The solution of this inverse problem is helpful in determining the internal geometry of micro- and nano-porous materials and the design of autonomous capillary pumps for microfluidic applications. Previous studies stated that the inverse problem is ill-posed in the sense that it has multiple solutions. Therefore, an approach was proposed to solve this problem, which requires measuring the imbibition kinematics in “both” capillary directions. In this Letter, we revisit the inverse problem of capillary imbibition, and two main results are achieved. The first is related to the ill-posedness of the inverse problem. We demonstrate that, contrary to what it was thought up until now, the inverse problem is well-posed and has a unique solution. The second main result relates to the solution of the inverse problem. Based on purely mathematical arguments, we propose an analytical solution of the inverse problem, which requires measuring the imbibition kinematics in only “one” tube direction. The analytical solution is validated using imbibition kinematics data obtained from two different sources: (a) from numerical simulations and (b) from published experimental work. The results show excellent agreement between the capillary radius obtained analytically and the true capillary radius profiles.