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Smart services' data-intensive nature means their convenience for users comes with privacy concerns. This poses challenges for the supply of smart services. This paper analyses the impact of user-differentiated privacy costs on smart service supply strategies. It also discusses the effects of privacy protections and data utilisation capabilities on the improvement of smart service levels. We find that providers tend to segment the market based on user privacy sensitivity to capture the maximum consumer surplus. Strict privacy protection requirements may cause providers to sacrifice service quality. Privacy protection is conducive to improving the level of smart services only when users fully recognise these services' value. Interestingly, our study finds improvements in service levels by providers are driven by two factors. On the one hand, providers choose to improve their service levels to obtain more data and create more profits. On the other hand, to reduce the opportunity costs of early investments to develop services, providers need to improve their capabilities to utilise the value of data, ultimately leading to improved service levels. This study brings a new perspective to the supply of smart services and offers suggestions for how to resolve the contradiction between smart service use and privacy preservation. [ABSTRACT FROM AUTHOR]

A series of Mg doped p-type multi-layered hBN films were prepared by atmospheric pressure chemical vapor deposition. Temperature dependent conductivity measurements were performed from 0.1 Hz to 10 MHz to analyze the characteristics of tail states close to the valence band edge. Jonscher's power law (A ω s ) is successfully applied to understand charge carrier transport through these states. In this work, exponent S increases from 0.6 → 0.8, 0.8 → 0.995, and 1.4 → 1.6 for samples B (precursor temperature, 750 °C), D (850 °C), and E (900 °C), indicating that non-overlapping small polaron tunneling dominates to 548 K. Polaron binding energies of 0.2–0.40 eV and tunneling distances <4.9 Å are calculated, confirming transport through localized states. The density of states near the Fermi level N(EF) was extracted from a fit to the AC conductivity data, yielding values of 10 15 and 10 17 e V − 1 c m − 3 as the precursor temperature increases. Singular Mg acceptor levels of 74, 30, and 17 meV are identified for each sample. A hole concentration from 6.5 × 1017 to 1 × 1018 cm−3 and carrier mobility from 18 to 25 cm2/V s is measured at 300 K. From RC fitting, carrier recombination lifetimes of 1.2, 0.4, and 0.35 μs are determined. Fermi's golden rule is used to determine an optical joint density of states of 1.1 × 1021 eV−1 cm−3 at a band edge. Overall, we show that AC conductivity is an effective method to evaluate midgap states in 2D (two-dimensional) materials at EF and p-type hBN possesses sufficient electrical properties to be integrated into a wide range of semiconductor applications. [ABSTRACT FROM AUTHOR]

Integration of photonic crystal (PhC) configurations onto the surfaces of light-emitting diodes (LEDs) can play an important role in enhancing light extraction efficiency. While the literature is rich with various PhC fabrication approaches, there is a need for high throughput methods that are appropriate for low-cost devices. In this paper, we report the use of single pulse laser interference lithography (LIL) for the fabrication of photonic crystal structures on LEDs. The use of brief nanosecond pulse exposures offers significant benefits for high-throughput production. In our study, we have applied single pulse LIL on GaAs/AlGaAs LED structures to achieve high-quality photoresist arrays and then have used inductively coupled plasma etching to create nanoholes into the epitaxial structure. The resulting array forms an effective PhC, controlling surface transmission. Electroluminescence (EL) analyses confirm that these structures enhance the average EL intensity of the LED by up to 3.5 times at room temperature. This empirical evidence underscores the efficacy and potential of this fabrication approach in advancing the functional capabilities of semiconductor-based light-emitting devices. [ABSTRACT FROM AUTHOR]

The target surface to be treated in reality is often not smooth and horizontal and may also be in different tilting angles. The treatment of the tilted dielectric surface by the atmospheric pressure plasma jet (APPJ) undoubtedly increases the complexity of surface modification. Therefore, a two-dimensional fluid model is established to reveal the internal mechanism of the interaction between the He APPJ and the tilted dielectric surface by means of numerical simulation. The distribution of the gas flow in a small angular range (0°, 3°, 5°, 8°, 10°, and 15°) is studied. In addition, the effects of the tilt angle on the jet morphology, discharge dynamic properties, and species distribution of the He APPJ are emphatically discussed. It is found that the jet morphology and parameters are no longer symmetrical under the tilted surface. With the increase in the tilt angle, the enhanced electric field in the upper surface region leads to the increase in the ionization rate and electron density here, and also accelerates the propagation speed of the jet to the dielectric surface in the atmospheric environment. Driven by the electric field force, the jet is closer to the dielectric surface, resulting in a decrease in the thickness of the cathode sheath and an increase in the surface charge density in the area to the right of the central axis. The influence of the gas flow structure leads to the shortening of the jet development distance and a decrease in the jet velocity on the upper surface. N and O also form higher fluxes on the upper surface due to the increase in the electron density. [ABSTRACT FROM AUTHOR]

This work proposed a fast inverse design method for microwave and infrared (IR) bi-stealth metamaterials based on the equivalent circuit model (ECM). Using this method, we designed a microwave and IR bi-stealth metamaterial by deploying a multilayered structure of the indium tin oxide (ITO) film based metasurface. First, the IR emissivity of the ITO film was calculated in the framework of the ECM. Then, an ITO metasurface was proposed to implement low IR emission and high microwave transmission simultaneously. Based on the ECM of the square patch, the ECM of the whole metamaterial was established at the microwave band. An inverse design program was built by incorporating the ECM with genetic algorithm (GA). Structure parameters of the metamaterial were optimized by GA to achieve the broadest microwave stealth bandwidth for the given thickness. Finally, the sample of the optimized bi-stealth metamaterial was prepared and tested. The calculated, simulated, and measured results are in good agreement, showing that such a metamaterial has an IR emissivity of 0.18 in the band from 3 to 14 μm and an efficient microwave stealth band from 4.8 to 17 GHz with a thickness of 4.9 mm. The proposed method will benefit the design and application of microwave and IR bi-stealth metamaterials. [ABSTRACT FROM AUTHOR]

The relative errors of virtual cathodes calculated by using the one-dimensional virtual cathode theory are analyzed and discussed. The studies of the error analysis show that the cathode temperature is the major factor affecting the calculated results of virtual cathodes, especially for calculations of the virtual cathode width. The smaller the virtual cathode produced by a hot cathode, the more significant the relative error of the virtual cathode caused by the uncertainties of electron emission parameters. Using the accurate cathode temperature, the potential barrier and the spatial width of virtual cathodes generated by a tungsten filament are calculated with experimental and theoretical electron emission parameters. The calculated results show that there is a strong linear correlation between the potential barrier of the virtual cathode and the heating current of the tungsten filament, which is independent of the electron collection current. With the increase in the heating current, the variation of the virtual cathode width is very sensitive to the relation between the electron collection current and the heating current. [ABSTRACT FROM AUTHOR]

Exploring potential two-dimensional monolayers with large photogalvanic effect (PGE) has been of great importance for developing self-powered optoelectronic devices. In this paper, we systematically investigate the generation of PGE photocurrent in chalcogen-based Janus XYZ monolayers (X/Y/Z = S, Se, Te; X ≠ Y ≠ Z) based on non-equilibrium Green's function formalism with density functional theory. The optimized Janus SSeTe, SeSTe, and TeSeS monolayers in the rectangular phase are shown stable and, respectively, possess 1.54, 1.49, and 1.74 eV indirect bandgaps. Illuminated by linearly polarized light, the PGE photocurrent without bias voltage can be collected in both armchair and zigzag directions. Unlike common Janus 2D materials with C3v symmetry, the photocurrent peak values of Janus XYZ monolayers do not come up with certain polarization angles, while the relations can be fitted by Iph = α sin(2θ) + β cos(2θ) + γ at each photon energy. Meanwhile, the maximum photoresponses of Janus SSeTe, SeSTe, and TeSeS monolayers are 2.02, 3.33, and 4.42 a20/photon, respectively. The relatively large PGE photocurrents and complicated polarization relations result from the lower symmetry of Janus XYZ monolayers. Moreover, the specific polarization angles for maximum photoresponses at each photon energy and the ratio between two transport directions are demonstrated, reflecting the anisotropy. Our results theoretically predict a potential Janus monolayer family for self-powered optoelectronic applications. [ABSTRACT FROM AUTHOR]

We have characterized polarization switching kinetics of Hf0.5Zr0.5O2 (HZO) at cryogenic temperature (T) down to 100 K. By the nucleation-limited-switching model with Lorentzian distribution fittings, the dependences of the average switching time (log τ1) and switching time distribution (ω) on T are extracted. As T decreases from 300 to 100 K, log τ1 first rapidly decreases and then gradually stabilizes. Meanwhile, ω exhibits different trends under different external electric fields (Eext), decreasing under low Eext while increasing under high Eext, eventually stabilizing at non-zero constants. With the further decrease in T (<100 K), log τ1 and ω exhibited by HZO are almost unchanged, indicating the intrinsic properties of ferroelectric multiple domains, which are different from the prediction in previous literature studies that log τ1 and ω will linearly decrease as T decreases. [ABSTRACT FROM AUTHOR]

Cu2AgBiI6 films were prepared by a one-step spin coating method, and flexible memristors with an Ag/PMMA/Cu2AgBiI6/ITO structure were constructed. The devices showed a bipolar resistive switching behavior with low switching voltage, which is beneficial for reducing energy consumption. Furthermore, this study found that the device exhibits an endurance of about 900 cycles, a higher ON/OFF ratio of over 103, a long retention time (∼104 s), and high stabilities against mechanical stress. Remarkably, the present flexible memristor displayed extraordinary flexibility and stability, with no significant change for the resistive switching behavior even at various bending angles or after undergoing 900 bending cycles. This study establishes that the lead-free halide perovskite Cu2AgBiI6 can be used for the resistive random-access memory of flexible electronics. [ABSTRACT FROM AUTHOR]

Research interest in thriving at work has burgeoned over the past decades, but little is known about how human resource (HR) practices affect employees' thriving at work. Drawing upon self‐determination theory and person‐organization fit theory, we developed and tested a moderated mediation model to explain how fun HR practices influence employees' thriving at work. The results of two studies, a scenario experiment (N = 164) and a time‐lagged survey (N = 253), supported our hypotheses. Specifically, the findings revealed that fun HR practices relates positively to employees' thriving at work. Autonomous motivation partially mediates the abovementioned relationship. Furthermore, fun HR practices translate into higher autonomous motivation and subsequent thriving at work for employees with higher preference for workplace fun. Our research contributes to the existing literature by identifying fun HR practices as an antecedent of thriving at work and revealing the psychological mechanisms through which fun HR practices affect employees' thriving at work. The practical implications, limitations, and future research avenues are also discussed. [ABSTRACT FROM AUTHOR]

Brand authenticity is a crucial concept in determining a continuing relationship between a team and its fans. To better understand brand authenticity in the sport industry, this study explored how professional sport teams' brand authenticity can be enhanced by its antecedents and what is the role of brand authenticity on fan loyalty, ultimately enhancing receptivity to environmental sustainability messaging. A total of 349 fans of the National Football League participated in an online survey. This research employed structural equation modeling to examine the relationships among the eight main constructs in the hypothesized research model. The results indicated that the five predictors positively influenced the team's brand authenticity. Furthermore, enhanced brand authenticity impacted fan loyalty, while receptivity to environmental sustainability messaging was affected by fan loyalty and environmental sustainability attitude. The findings demonstrate how sport organizations can increase fans' receptivity to environmental sustainability messaging through fans' perceived brand authenticity and loyalty. [ABSTRACT FROM AUTHOR]

We argue that institutional brokerage networks facilitate liquidity provision and mitigate the price impact of large non-information-motivated trades. Using commissions, we map trading networks of mutual funds (institutions) and their brokers. Central funds (institutions) tend to outperform their peripheral counterparts in terms of return gap (execution shortfall). This outperformance is more pronounced when funds experience large outflows and for large trades in less liquid stocks. Central brokers can deliver superior trade execution compared to peripheral brokers, but mainly for central institutions. We use the collapse of Lehman Brothers as a quasi-natural experiment to establish the likely causality of our findings. [ABSTRACT FROM AUTHOR]

Purpose: Performing back squats with elastic bands has been widely used in resistance training. Although research demonstrated greater training effects obtained from adding elastic bands to the back squat, little is known regarding the optimal elastic resistance and how it affects neuromuscular performance. This study aimed to compare the force, velocity, power, and muscle activity during back squats with different contributions of elastic resistance. Methods: Thirteen basketball players performed 3 repetitions of the back squat at 85% of 1-repetition maximum across 4 conditions: (1) total load from free weight and (2) 20%, (3) 30%, and (4) 40% of the total load from elastic band and the remaining load from free weight. The eccentric and concentric phases of the back squat were divided into upper, middle, and bottom phases. Results: In the eccentric phase, mean velocity progressively increased with increasing elastic resistance, and muscle activity of the vastus medialis and rectus femoris significantly increased with the largest elastic resistance in the upper phase (P ≤.036). In the concentric phase, mean power (P ≤.021) and rate of force development (P ≤.002) significantly increased with increasing elastic resistance. Furthermore, muscle activity of the vastus lateralis and vastus medialis significantly improved with the largest elastic resistance in the upper phases (P ≤.021). Conclusion: Velocity, power, rate of force development, and selective muscle activity increased as the elastic resistance increased in different phases during the back-squat exercise. [ABSTRACT FROM AUTHOR]

We employed first-principles calculations to investigate the effect of chemical doping on the lithiation kinetics and dynamic properties of the c–Si anode. Our ab initio molecular dynamics simulations reveal that phosphorous/arsenic doping can greatly enhance the lithiation kinetics of c–Si, whereas boron doping is unable to produce such an improvement. Our calculations also show that boron doping could enhance Li insertion into c–Si, but phosphorous/arsenic doping tends to increase the insertion energy of Li ions. Although the migration energy barriers of Li ions may slightly increase (decrease) in the boron-(phosphorus-/arsenic-)doped c–Si, these changes were only effective within the range of the nearest-neighbor distance from dopants. Furthermore, it was found that the phosphorus-/arsenic-doped Si can be more ductile and can more easily undergo plastic deformation upon lithiation, while the c–Si matrix becomes more brittle and stiffer when doped with boron. Our simulation results also demonstrate that phosphorous- and arsenic-doping can effectively speed up the Li-induced structural amorphization of c–Si while boron doping appears to severely slow it down. These findings unambiguously indicate that the induced mechanical softening of the c–Si bond network can be the primary factor that leads to the enhanced lithiation kinetics in the n-type doped c–Si anodes. [ABSTRACT FROM AUTHOR]

Traditional Kinetic Monte Carlo (KMC) approaches, rooted in Gillespie's stochastic simulation algorithm, become computationally demanding in systems with a large range of timescales. The goal of this work is to propose and study new adaptive lattice-KMC time integration strategies for spatially non-uniform systems. To that end, two novel adaptive tau-leaping methods and their corresponding time integration strategies are developed based on the idea of the "n-fold" direct KMC method. These strategies allow for the simultaneous execution of multiple reactions, advancing time by adaptively selected coarse increments. We present numerical experiments comparing the proposed methods with existing approaches in a catalytic surface kinetics application involving ammonia decomposition. [ABSTRACT FROM AUTHOR]

Stochastic lattice-gas models provide the natural framework for analysis of the surface diffusion-mediated evolution of crystalline metal nanostructures on the appropriate time scale (often 101–104 s) and length scale. Model behavior can be precisely assessed by kinetic Monte Carlo simulation, typically incorporating a rejection-free algorithm to efficiently handle the broad range of Arrhenius rates for hopping of surface atoms. The model should realistically prescribe these rates, or the associated barriers, for a diversity of local surface environments. However, commonly used generic choices for barriers fail, even qualitatively, to simultaneously describe diffusion for different low-index facets, for terrace vs step edge diffusion, etc. We introduce an alternative Unconventional Interaction–Conventional Interaction formalism to prescribe these barriers, which, even with few parameters, can realistically capture most aspects of behavior. The model is illustrated for single-component fcc metal systems, mainly for the case of Ag. It is quite versatile and can be applied to describe both the post-deposition evolution of 2D nanostructures in homoepitaxial thin films (e.g., reshaping and coalescence of 2D islands) and the post-synthesis evolution of 3D nanocrystals (e.g., reshaping of nanocrystals synthesized with various faceted non-equilibrium shapes back to 3D equilibrium Wulff shapes). [ABSTRACT FROM AUTHOR]

Temperature-dependent piezoelectric-field characteristics of GaInN/GaN blue quantum wells are experimentally investigated between 100 and 300 K. The results show that the magnitude of the piezoelectric field increases with decreasing temperature with a slope of 1.08 kV cm−1 K−1 due to the increase in a mismatch between thermal expansion coefficients. To understand the impact of temperature-dependent piezoelectric field on the device performance, the external quantum efficiencies (EQEs) of a blue light-emitting diode are measured in the same temperature range. More severe EQE droops are observed at lower temperatures, which can be attributed to the increase in carrier overflow/spill-over to the p-clad layer enhanced by the stronger piezoelectric fields. The larger blueshifts in mean photon energy are simultaneously observed at lower temperatures, which also confirms the stronger piezoelectric fields at lower temperatures. [ABSTRACT FROM AUTHOR]

α-Al2O3 is renowned for its extensive bandgap and diverse applications in electronic and optoelectronic devices. Employing density-functional theory-based methods, this study investigates the feasibility of chalcogen doping (S, Se, Te) in α-Al2O3. Standard modeling tools are utilized to construct α-Al2O3 supercells, focusing on the calculations of individual chalcogen-related and native point defects resulting from single-atom doping. Our analysis systematically explores the formation energies and transition levels associated with chalcogen (S, Se, Te) doping in oxygen (or aluminum) sites in Al-rich (or O-rich) limits. We observe a trend where increasing atomic number (from S to Te) correlates with a higher difficulty in forming anion-doped α-Al2O3, but a lower barrier to cationic doping. The results indicate a preferential substitution of chalcogen atoms for aluminum in O-rich environments. Specifically, in varying oxygen conditions, the dominant defect types, their prevalence, and defect formation energies in α-Al2O3 are significantly altered following chalcogen doping, offering new insights into defect processes in α-Al2O3. [ABSTRACT FROM AUTHOR]

Immigrants and their native-born children often face considerable wage penalties relative to natives, but less is known about whether this inequality arises through differences in educational qualifications, segregation across occupations and establishments, or unequal pay for the same work. Using linked employer–employee data from Norway, the authors ask whether immigrant–native wage disparities 1) reflect differences in detailed educational qualifications, labor market segregation, or within-job pay differences; 2) differ by immigrant generation; and 3) vary across different segments of the labor market. They find that immigrant–native wage disparities primarily reflect sorting into lower-paying jobs, and that wage disadvantages are considerably reduced across immigrant generations. When doing the same work for the same employer, immigrant-background workers, especially children of immigrants, earn similar wages to natives. Sorting into jobs seems more meritocratic for university graduates, for professionals, and in the public sector, but within-job pay differences are strikingly similar across market segments. [ABSTRACT FROM AUTHOR]

This study posits that the use of artificial intelligence (AI) enables supply chains (SCs) to dynamically react to volatile environments, and alleviate potentially costly decision-makings for small-medium enterprises (SMEs). Building on a resource-based view, this work examines the impact of AI on SC risk management for SMEs. A structural model comprising of AI-risk management capabilities, SC re-engineering capabilities and supply chain agility (SCA) was developed and tested based on data collected from executives, managers and senior managers of SMEs The main methodological approach used in this study is partial least squares-based structural equation modelling (PLS-SEM) and artificial neural network (ANN). The results identified the use of AI for risk management influences SC re-engineering capabilities and agility. Re-engineering capabilities further affect and mediate agility. PLS-SEM and ANN were compared and the results revealed consistency for models A and B. Current levels of demand uncertainties in the SC challenges managers in making complex trade-off decisions that require huge management resources in very limited time. With AI, it is possible to model various scenarios to answer crucial questions that archaic infrastructures are not able to. This study combines a multi-construct agility concept and identified non-linear relationships in the model. [ABSTRACT FROM AUTHOR]

Business-to-business suppliers invest in safety training programs believing that such programs mitigate safety hazards, prevent workplace injuries, and create value for their customers. However, causal evidence of these effects is sparse. Study 1 uses site-level monthly data from a global oil field services company. Exploiting sharp discontinuities in safety training hours due to catastrophic accidents, the authors find that a 10% increase in safety training hours per capita decreases safety hazards per capita by 6.45%–9.57%. Study 2 measures the causal impact of business establishments' safety training intensity on their workplace injuries: it leverages Local Law 196 requiring workers at construction establishments in New York City to complete at least ten hours of safety training. This legislation reduced injury rates at construction establishments in New York City by.54–.68 percentage points (a 15.56%–18.84% decrease) relative to their counterparts. Study 3, a stated-choice conjoint experiment of business-to-business procurement professionals, documents that the focal supplier's investment in safety training increases the probability of its proposal being selected by those professionals. Collectively, these findings validate the need for suppliers to invest in safety training as a risk-mitigation vehicle that has positive implications for business-to-business buying decisions. [ABSTRACT FROM AUTHOR]

Molecular chirality is represented as broken mirror symmetry in the structural orientation of constituent atoms and plays a pivotal role at every scale of nature. Since the discovery of the chiroptic property of chiral molecules, the characterization of molecular chirality is important in the fields of biology, physics, and chemistry. Over the centuries, the field of optical chiral sensing was based on chiral light–matter interactions between chiral molecules and polarized light. Starting from simple optics-based sensing, the utilization of plasmonic materials that could control local chiral light–matter interactions by squeezing light into molecules successfully facilitated chiral sensing into noninvasive, ultrasensitive, and accurate detection. In this Review, the importance of plasmonic materials and their engineering in chiral sensing are discussed based on the principle of chiral light–matter interactions and the theory of optical chirality and chiral perturbation; thus, this Review can serve as a milestone for the proper design and utilization of plasmonic nanostructures for improved chiral sensing. [ABSTRACT FROM AUTHOR]

Carbon nanotubes have shown great promise for high-performance, large-area, solution processable field-effect transistors due to their exceptional charge transport properties. In this study, we utilize the spin-coating method to form networks from selectively sorted semiconducting single-walled carbon nanotubes (s-SWNTs), aiming for scalable electronic device fabrication. The one-dimensional nature of s-SWNTs, however, introduces significant roughness and charge trap sites, hindering charge transport due to the van der Waals gap (∼0.32 nm) between nanotubes. Addressing this, we explored the effects of anion doping on the spin-coated s-SWNT random network, with a focus on the influence of the small size of halogen anions (0.13–0.22 nm) on these electronic properties. Raman and ultraviolet–visible–near-infrared optical spectroscopy results indicate that smaller anions significantly enhance doping effects through strong non-covalent anion–π interactions, improving charge transport and carrier injection efficiency in s-SWNTs, especially for n-type operation. This improvement is inversely proportional to the size of the halogen anions, with the smallest anion (fluorine) effectively transitioning the electrical characteristics of the s-SWNT network from ambipolar to n-type by reducing both junction and contact resistances through anion doping, based on anion–π interaction. [ABSTRACT FROM AUTHOR]

To study the effect of large area uniform garnet film on the consistency of image quality of a magneto-optical imaging system, the effect of lattice mismatch on a large area uniform domain structure of magneto-optical materials was studied. In this paper, (BiTm)3(GaFe)5O12 thin garnet films with different stress were prepared on the surface of gadolinium gallium garnet by liquid phase epitaxy. The results show that the magnetic hysteresis mechanism exists in the (BiTm)3(GaFe)5O12 thin films with tensile stress, and the domains can preferentially respond to magnetic signals in very small regions. This is mainly the phenomenon of magnetic domain partitioning caused by cracks. In addition, the non-uniform distribution of coercive force in a large range is the main cause of hysteresis. The thin films with weak compressive stress (BiTm)3(GaFe)5O12 are uniformly distributed over a large area. [ABSTRACT FROM AUTHOR]

We successfully synthesized tetragonal FeS with various Fe:S molar ratios using a hydrothermal method, and the EDS and XRF results confirmed that FeS exhibits superconductivity within the Fe and S element ratio range of 1.155–1.274, rather than a strict stoichiometric ratio. The reaction temperature can not only play a crucial role in determining the purity of the obtained FeS phase but also significantly alter its micromorphology. Significantly, by analyzing the relationship between the Fe:S actual molar ratio and Tc as well as the Fe:S actual molar ratio and unit cell volume, FeS exhibits dome-shaped superconductivity and shows a negative correlation with Tc and chemical pressure. Furthermore, considering the correlation between anion height (hanion) and Tc, Tc reaches the maximum value of 4.53 K for hanion ≈ 1.28 Å, a behavior distinct from that of observed in Fe-pnictide superconductors. In short, our experimental results provide a unique perspective to deepen our understanding of FeS superconductors. [ABSTRACT FROM AUTHOR]

The structural parameters, electron localization functions, electron paramagnetic resonance (EPR) parameters, formation energies, and thermodynamic transition levels of various oxygen vacancy defects in amorphous silica are comprehensively and integrally investigated by using density functional theory. The trends of changes in the oxygen vacancy defect structure and electron localization induced by the increase in distance between defective silicon atoms are clearly identified. It is shown that the dimer configuration may be the potential structure of the E δ ′ center. For the back-projected unpuckered configuration and the puckered configuration, whose EPR parameters are more consistent with the experimental values of the E γ ′ center, the unpaired electron localized on the sp3 hybridized silicon atom is a common feature. Due to the three-coordinated oxygen atom in the forward-oriented configuration, the EPR parameters are closest to those of the E α ′ center. Transformations of oxygen vacancy defects under different charge states are studied by sequentially adding and removing electrons. The thermodynamic transition level analysis reveals that the dimer and forward configurations may behave as deep traps for electron accumulation. The back-projected puckered fourfold-coordinated and fivefold-coordinated configurations are comparatively stable and may be able to function as shallow traps for electron transport. The neutral double unpuckered, neutral back-projected puckered fourfold-coordinated, and neutral back-projected unpuckered configurations are more likely to lose electrons during hole trapping. As the bias voltage is repeatedly changed, the defect density of the puckered configuration may reduce, while that of the dimer and unpuckered configuration may take an opposite trend. [ABSTRACT FROM AUTHOR]

This study investigates the stability of the (Hf,Zr)O2 (HZO) and AlScN thin films against the depolarization effect. In order to adversely interfere with the polarization screening of ferroelectric (FE) film and induce the depolarization effect, an Al2O3 film was inserted between the TiN bottom electrode and the FE film. Subsequently, to minimize charge injection through Al2O3 films, the double remanent polarization–voltage (2Pr–V) curve was measured employing voltage pulses with 1 μs-length. As the thickness of the Al2O3 film increased, the charge injection through the Al2O3 film decreased, leading to a decrease in the slope of the 2Pr–V curve. The magnitude of the depolarization field applied to the FE film was determined by simulating the 2Pr–V curve using an equivalent circuit model. Subsequently, the proportion of reversed domains during the delay period due to the depolarization effect was measured. It was revealed that HZO films exhibited vulnerability to the depolarization effect, with 16% of domains being reversed. On the other hand, AlScN films demonstrated superior stability, with polarization loss of less than 1%. Ultimately, it was revealed that AlScN films demonstrated superior stability against the depolarization effect compared to HZO films due to their higher coercive field and more uniform polarization distribution across the film area. [ABSTRACT FROM AUTHOR]

Polarization is one of the fundamental properties of light and has an important application value, involving multiple fields, such as imaging, display, quantum computing, and biosensing. The artificial metasurface can achieve comprehensive control of electromagnetic waves, such as amplitudes, phases, and polarization states. Compared to traditional optical devices, the metasurfaces have advantages, such as small size and diverse functions, meeting the needs of modern optical systems for ultra-lightweight, ultra-compact, and multifunctional optical components. Chiral media are widely presented in various macroscopic and microscopic systems in nature. Circular dichroism (CD) is commonly used to describe the difference in absorption rates of left-handed circularly polarized light and right-handed circularly polarized light in chiral media. However, the optical response of chiral media in nature is usually weak and mainly located in the ultraviolet band, which limits their detection sensitivity and practical application range. In this work, we proposed a chiral metasurface model with four rectangular holes with proper rotation. By rotating the rectangular or elliptical holes at a certain angle, the symmetry of the structure is disrupted, making it chiral. The proposed metasurface devices were fabricated, and the optical measurements were performed, which were in good agreement with the designs. The normalized CD values are around 0.01 at the near-infrared region. This work provides a complete procedure of the metasurface device and initials chiral-tunable flat meta-devices. It also has broad application prospects in fields, such as polarization imaging, life sciences, and drug chiral detection. [ABSTRACT FROM AUTHOR]

The evaporation-induced deposition pattern of the linear diblock copolymer solution has attracted attention in recent years. Given its critical applications, we study deposition patterns of the linear diblock copolymer solution nanodroplet on a solid surface (the wall) by molecular dynamics simulations. This study focuses on the influence of the nonbonded interaction strength, including the interaction between the wall and polymer blocks (ɛAW and ɛBW), the interaction between the solvent and the wall (ɛSW), and the interaction between polymer blocks (ɛAB). Conditions leading to diverse deposition patterns are explored, including the coffee-ring and the volcano-like structures. The formation of the coffee-ring structure is attributed to receding interfaces, the heterogeneity inside the droplet, and the self-assembly of polymer chains. This study contributes to the establishment of guidelines for designing deposition patterns of the linear diblock copolymer solution nanodroplet, which facilitates practical applications such as inkjet printing. [ABSTRACT FROM AUTHOR]

Grazing incidence x-ray diffraction reveals that conventional post-deposition-annealed ZrO2 and in situ crystallized (by local epitaxy) ZrO2 thin films (<15 nm) have different internal strain states. A comparison between single- and two-step grown films enables the diverse strain components to be discretely identified. In particular, thickness-dependent intrinsic growth strain is unevenly distributed within the film according to the Volmer–Weber growth. Furthermore, extrinsic thermal strain, locally present in the annealed seed layer, does not spread over the in situ crystallized upper main layer of the two-step film. Post-deposition annealing of the two-step film renders the strain state identical to the single-step films by imposing thermal strain on the in situ crystallized main layer. Local strains created by diffused aluminum and yttrium dopants are also examined. Since each stress factor plays a vital role in the phase formation and electrical behaviors of ZrO2 and other fluorite-structure films, this method will pave the way for understanding the film's internal strain distribution and accompanying performance engineering. [ABSTRACT FROM AUTHOR]

The advent of Neural-network Quantum States (NQS) has significantly advanced wave function ansatz research, sparking a resurgence in orbital space variational Monte Carlo (VMC) exploration. This work introduces three algorithmic enhancements to reduce computational demands of VMC optimization using NQS: an adaptive learning rate algorithm, constrained optimization, and block optimization. We evaluate the refined algorithm on complex multireference bond stretches of H2O and N2 within the cc-pVDZ basis set and calculate the ground-state energy of the strongly correlated chromium dimer (Cr2) in the Ahlrichs SV basis set. Our results achieve superior accuracy compared to coupled cluster theory at a relatively modest CPU cost. This work demonstrates how to enhance optimization efficiency and robustness using these strategies, opening a new path to optimize large-scale restricted Boltzmann machine-based NQS more effectively and marking a substantial advancement in NQS's practical quantum chemistry applications. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride (h-BN) has excellent thermal conductivity and dielectric properties, which shows great potential for low-dimensional devices. However, mechanical properties of h-BN have not been comprehensively investigated through experiments. In this work, we conduct in situ direct tensile tests on freestanding single-crystal few-layer h-BN nanosheets with various layer numbers from 3 to 8, with an elaborate sample transfer and characterization protocol. Young's modulus of 573.8 ± 101.4 GPa and a tensile fracture strain up to 3.2% are revealed, which are comparable to its monolayer counterpart. Moreover, we find a tough-to-brittle transition in few-layer h-BN with the increase in layer number, which is attributed the interplay between the van der Waals interaction and in-plane covalent bonding. These findings could open up new possibilities in mechanical research of van der Waals materials and provide guidance for the design of h-BN-based devices and composites. [ABSTRACT FROM AUTHOR]

A precise description of the thermodynamic states of gaseous and solid detonation products is essential when using thermodynamic calculations to determine the detonation performance and destructive power of explosives. For high oxygen-lean explosives (the oxygen contained in explosives is insufficient to completely oxidize combustible elements and excess solid carbon will be generated in the detonation products), the phase state of solid carbon product affects the Chapman–Jouguet (CJ) detonation performance parameters, reaction zone, and energy release process. However, the recovery of detonation products demonstrates that the actual detonation carbon product is primarily a mixed state of diamond/graphite stack, as opposed to the existing thermodynamic codes, which essentially treat detonation carbon as single-phase carbon. To understand the thermodynamic effect of the mixed carbon phase state on the non-ideal detonation behavior, in this work, the matching relationship among the VINET equation of state parameters, thermodynamic potential parameters of the solid products of the equivalent system and the phase mixed system was constructed by using the nonlinear fitting method. The relationship between the carbon phase composition at the CJ point and the explosive composition structure was researched. Investigations were conducted into how the mixed carbon phase affected the volume and content of gas products as well as the composition at CJ points. Diamond formation in products is good for enhancing explosive's working capacity. Based on mixed-state potential parameters, the correlation mechanism between the mixed carbon phase and the chemical reaction zone was investigated, and it was found that intramolecular carbon/intermolecular carbon and more detonation graphite/diamond products all would lead to the extension of the reaction zone. [ABSTRACT FROM AUTHOR]

This paper addresses a serial distributed permutation flowshop scheduling problem (SDPFSP) inspired by a printed circuit board assembly process that contains two production stages linked by a transportation stage, where the scheduling problem in each production stage can be seen as a distributed permutation flowshop scheduling problem (DPFSP). A sequence-based mixed-integer linear programming model is established. A solution representation consisting of two components, one component per stage, is presented and a makespan calculation method is given for the representation. Two suites of accelerations based on the insertion neighbourhood are proposed to reduce the computational complexity. A cooperative iterated greedy (CIG) algorithm is developed with two subloops, each of which optimises a component of the solution. A collaboration mechanism is used to conduct the collaboration of the two subloops effectively. Problem-specific operators including the NEH-based heuristics, destruction, reconstruction and three local search procedures, are designed. Extensive computational experiments and statistical analysis verify the validity of the model, the effectiveness of the proposed CIG algorithm and the superiority of the proposed CIG over the existing methods for solving the problem under consideration. [ABSTRACT FROM AUTHOR]

Within cell plasma membranes, unsaturated lipids are asymmetrically distributed over the inner and outer leaflets, offering an attractive local structural feature. However, the mechanism to keep lipid transmembrane asymmetry and the closely related transmembrane movement (flip-flop) for unsaturated lipids remain poorly understood. Here, we applied sum frequency generation vibrational spectroscopy to investigate this lipid transmembrane asymmetry upon mimicking the cell membrane homeostatic processes. On the one hand, unsaturated lipids were found to hinder the flip-flop process and preserve lipid transmembrane asymmetry in model cell membranes, owing to the steric hindrance caused by their bent tails. On the other hand, local unsaturated lipids in the mixed unsaturated/saturated lipid bilayer were conducive to the formation of the local asymmetry. Therefore, lipid unsaturation can be recognized as an intrinsic key factor to form and maintain lipid transmembrane asymmetry in cell membranes. [ABSTRACT FROM AUTHOR]

The acid-resistant tungsten trioxide photoelectrochemical solid–liquid ultraviolet (UV) photodetector uses a thin film of tungsten trioxide as the photoelectrode, forming a stable heterojunction with the electrolyte. This study employed band theory and double electron layer theory to analyze the mechanisms underlying the effect of pH on the redox potential and photocurrent, utilizing the ion product constant of water and the Nernst equation. By applying the principles of energy band theory and the two-electron layer model, the electron transfer process was analyzed and explained. These findings hold significant promise for enhancing solid–liquid heterojunction UV photodetectors. Tungsten trioxide has fast response and high sensitivity under extreme conditions. The device performance of WO3 nanosheets fabricated by annealing at 300 °C for one hour is excellent, including a rise time of 0.7 s, decay time of 6.8 s, photosensitivity of 1.90, and photoresponsivity of 2.31 mA/W. 0.5M sulfuric acid produced the highest photocurrent (5.46 μA) and sensitivity (14.07). This material has potential applications in optoelectronics, catalysis, sensing, water treatment, and air purification. [ABSTRACT FROM AUTHOR]

In this study, phase transitions (structural and magnetic) and associated magnetocaloric properties of stoichiometric MnCoGe have been investigated as a function of annealing pressure. Metastable phases were generated by annealing at 800 ° C followed by rapid cooling under pressures up to 6.0 GPa. The x-ray diffraction results reveal that the crystal cell volume of the metastable phases continuously decreases with increasing thermal processing pressure, leading to a decrease in the structural transition temperature. The magnetic and structural transitions merge and form a first-order magnetostructural transition between the ferromagnetic orthorhombic and paramagnetic hexagonal phases over a broad temperature range (>80 K) spanning room temperature, yielding considerable magnetic entropy changes. These findings demonstrate the utility of thermal processing under high pressure, i.e., high-pressure annealing, to control the magnetostructural transitions and associated magnetocaloric properties of MnCoGe without altering its chemical composition. [ABSTRACT FROM AUTHOR]

We introduce a novel application of machine learning to compare pooling and servicing agreements (PSAs) that govern commercial mortgage-backed securities. In contrast to the view that the PSA is largely boilerplate text, we document substantial variation across PSAs, both within- and across-underwriters and over time. A part of this variation is driven by differences in loan collateral across deals. Additionally, we find that differences in PSAs are correlated with ex post loan and bond performance. Collectively, our analysis suggests the importance of examining the entire governing document, rather than specific components, when analyzing complex financial securities. [ABSTRACT FROM AUTHOR]

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Lot streaming technology enables continuous overlapping operations, which is of great significance in shortening production cycles, reducing unnecessary waiting time, and increasing production capacity. However, the capacity constraint of batch processing machines may lead to inevitable variations in sublots. Therefore, the key focus of our research is to control variations of sublot for maximising benefits. In view of this, we investigate a hybrid flowshop scheduling problem (HFSP) with batch processing machines and variable sublots (HFSP-BVS) integrating sequence-dependent setup times and transportation times. To address HFSP-BVS, a MILP model is first established, and a novel collaborative iterative greedy (NCIG) algorithm is proposed to optimise the cumulative payoffs associated with delivery dates. In NCIG, a collaborative initialisation method by extracting good information from an archive is proposed, and a specific destruction-reconfiguration strategy is designed to control the variations of sublots in the batch processing stage. Furthermore, a dynamic acceptance criterion is designed to balance the algorithm's exploitation and exploration capabilities. Lastly, we conduct comparisons between the NCIG algorithm and five other metaheuristic algorithms on 100 test instances. The results show that NCIG outperforms them by 1.89% and 61.42% on average in terms of the total penalty and RPI values, respectively. [ABSTRACT FROM AUTHOR]

As mobile devices have become a necessity in our daily lives, mobile advertising is also prevalent. Accordingly, it is critical for practitioners to understand how consumers visually attend to mobile advertisements. One popular way of doing so is via eye-tracking methodology. However, scant eye-tracking research exists in mobile settings due to technical challenges, e.g., cumbersome data annotation. To tackle these challenges, the authors propose an object-detection machine learning (ML) algorithm—You Only Look Once (YOLO) v3—to analyze eye-tracking videos automatically. Moreover, we extend the original YOLO v3 model by developing a novel algorithm to optimize the analysis of eye-tracking data collected from mobile devices. Through a lab experiment, we investigate how two types of ad elements (i.e., textual vs. pictorial) and shopping devices (i.e., mobile vs. PC) affect consumers' visual attention. Our findings suggest that (1) textual ad elements receive more attention than pictorial ones, and such differences are more pronounced in ads on mobile devices than those on PCs; and (2) mobile ads receive less attention than PC ads. Our findings provide managerial insights into developing effective digital advertising strategies to improve consumers' visual attention in online and mobile advertisements. [ABSTRACT FROM AUTHOR]

The introduction of the Beijing–Shanghai high-speed rail (Launch) and the Wenzhou bullet-train collision (Crash) in China provided a unique occasion to study the effect of competition on price dispersion. Results show that price dispersion increased by about 48% after the Launch, as airlines offered greater discounts to price-elastic consumers than to price-inelastic consumers. By contrast, price dispersion decreased by about 55% after the Crash, as airlines raised prices more for price-elastic consumers than for price-inelastic consumers. [ABSTRACT FROM AUTHOR]

The rapid development of deep learning techniques has driven the emergence of a neural network-based variational Monte Carlo (VMC) method (referred to as FermiNet), which has manifested high accuracy and strong predictive power in the electronic structure calculations of atoms, molecules, and some periodic systems. Recently, the implementation of the effective core potential (ECP) scheme has further facilitated more efficient calculations in practice. However, there is still a lack of comprehensive assessments of the ECP's performance under the FermiNet. In this work, we set sail to fill this gap by conducting extensive tests on the first two row elements regarding their atomic, spectral, and molecular properties. Our major finding is that, in general, the qualities of ECPs have been correctly reflected under FermiNet. Two recently built ECP tables, namely, correlation consistent ECP (ccECP) and energy consistent correlated electron pseudopotential (eCEPP), seem to prevail in terms of overall performance. In particular, ccECP performs slightly better on spectral precision and covers more elements, while eCEPP is more systematically built from both shape and energy consistency and better treats the core polarization. On the other hand, the high accuracy of the all-electron calculations is hindered by the absence of relativistic effects as well as the numerical instabilities in some heavier elements. Finally, with further in-depth discussions, we generate possible directions for developing and improving FermiNet in the near future. [ABSTRACT FROM AUTHOR]

The surface properties of nickel-based alloys with different alloying compositions against aggressively corrosive species were systematically evaluated by using the segregated and non-segregated models designed through first-principles calculations. The presence of typical VIB alloying elements such as chromium (Cr), molybdenum (Mo), and tungsten (W) elements near the nickel surface was identified to significantly enhance the surface adsorption of water molecules (H2O) and their decomposed products (OH, O, and H). The doping patterns and surface electronic structures were found to determine the adsorption diversity of these substances. Consequently, adsorbates containing oxygen were likely to induce the segregation tendencies of these selected alloying elements from the deep area of nickel toward the top-most surface layer (TSL). The electrode potential shifts of the surface Ni atom in the designed alloying systems, compared to the bare Ni (111) surface, were further calculated to identify the beneficial electrochemical performance of alloy surfaces in the absence/presence of various adsorbates. In vacuum, the locations of these alloying elements in the near-surface layers would more increase the electrode potential shifts, thereby delaying the dissolution of Ni atoms from metal substrates. Nevertheless, the presence of adsorbates led to notably negative electrode potential shifts for the Ni (111) surface, among which the decomposed products (hydroxyl and oxygen) were of the most passive effects on corrosion behavior of nickel. The detrimental effects of these adsorbates on surface stability would be effectively alleviated with the aid of atomic VIB alloying elements of nickel-based alloys, especially W segregation to the TSL regardless of the pH in aqueous environments. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have attracted widespread attention from scholars as a new type of material employed in extreme environments. However, as a main kind of HEAs, many face-centered cubic single-phase HEAs are restricted in industrial applications due to their lower yield strength and high cost when containing expensive elements such as Co. In this study, dispersion strengthening by heat treatment was introduced in low-cost Co-free Fe40Mn20Cr20Ni20 HEA to improve its strength, and its high-temperature tensile behavior and constitutive model were studied to explore its potential application at high temperatures. It is found that when subjected to quasi-static room-temperature stretching, the heat-treated sample exhibits a yield strength of 534 MPa and a tensile plasticity of 26.8%. In addition, the tensile behavior of samples after heat treatment was investigated at high temperature (573–873 K) and low strain rate (10−3–10−1 s−1). The results suggest that the yield strength decreases with increasing temperature and decreasing strain rate. Moreover, at 873 K and 10−3 s−1, the electron backscatter diffraction system and x-ray diffraction results of the deformed sample indicate that the softening curve is driven from the recovery of materials. Finally, the flow stress was predicted using the Arrhenius equation and Artificial Neural Network model (ANN), and the two models were assessed using the average absolute relative error and coefficient of correlation (R). The results showed that the ANN had higher accuracy. [ABSTRACT FROM AUTHOR]

Nanostructured high-entropy alloys (HEAs) are promising candidates for extreme load-bearing applications due to their superior performance. In this work, we investigate the deformation behaviors of CoCrFeMnNi HEA under high-speed impact by molecular dynamics simulations. Compared with Al, Ni, and Cu representing pure metals with low to high stacking fault energies, it is found that the CoCrFeMnNi HEA exhibits remarkably low twinning density under shock, despite its extremely low stacking fault energy. Shear loading is then applied to stacking-faulted HEAs and these pure metals to study the evolution of stacking faults under shear stress. The results further show a low tendency for stacking faults to transform into deformation twinning in HEAs, regardless of the initial density of stacking faults. The energy path for deformation twins and stacking faults was calculated, and a direct comparison of fault energies could not explain the deformation mechanism of HEA. We reveal that the inhomogeneous energy profile of dislocation slip caused by the inherent heterogeneity of HEA leads to dispersed stacking fault propagation, which suppresses twinning formation. These results address the spatially tunable defects and further urgent need for the synergistic design of components and microstructures in HEAs. [ABSTRACT FROM AUTHOR]

Muon radiography, which relies on measuring the absorption and attenuation of muons as they pass through matters, offers a new imaging technique capable of revealing the internal structure of large objects. Recent technological advancement allows for the application or testing of muon radiography in various fields, including mining, civil engineering, security check, etc. This study investigates the factors that influence muon radiography, which is used in density inversion, through simulations and experiments. The materials considered for density inversion include water, standard rock, and iron. Our simulation studies show that the number of events detected and selected has an impact on the reconstruction results, and several factors, such as multiple Coulomb scattering processes, recording time, and spatial resolution, which influence the number of muons, must be taken into account when measuring the rock density. We design and conduct a laboratory scale experiment based on the simulation results. We filter the 220 h of recording signals through time coincidence and straight-line fitting to obtain the selected events. Our results reveal that the statistical error of muons survival ratio in recording time significantly impacts the inversion result and decreases the error can improve accuracy greatly. In the experiment, the deviation between the inversion mean value and the expected value can be reduced to 2.4%–2.9% for iron, 7% for water, and 1.5% for standard rock. This density inversion approach provides insight into future density detection of underground structures. [ABSTRACT FROM AUTHOR]