Search

Mechanical engineering of 2D materials allows continuous and reversible modulation of their electronic and photonic properties. Although photoluminescence (PL) measurement is an effective way to monitor the effects of mechanical forces on 2D semiconductors, there is currently a lack of techniques to enhance PL signals during stress application. This study presents an innovative mechanical engineering approach that integrates a dielectric microsphere as an atomic force microscopy (AFM) probe into a Raman-AFM system. Force–distance curve tests and COMSOL simulations were performed to analyze and estimate the compressive stress exerted by the microsphere. Importantly, the PL signals of transition metal dichalcogenides subjected to microsphere probe's force were enhanced and reveal distinct mechanical responses depending on the substrate rigidity: compressive pressures for rigid substrates and tensile strains for flexible ones. Notably, this strategy not only amplifies spectral signals in real time but also achieves fine stress modulation in the precise targeted material region, demonstrating its superiority in sensitive mechanical engineering applications. Our work offers a new avenue for the deliberate design of mechanical strains in 2D materials, which is crucial for optimizing the performance of related devices. [ABSTRACT FROM AUTHOR]

Natural flavonoids have been shown to have many pharmacological activities. Efficient and continuous enrichment of total flavonoids with high content and low mobile phase usage from complex natural products is greatly needed at the moment. In this study, a new continuous chromatography system (CCS) with 6 zones and the 18-column dynamic tandem connection technique was developed and used to enrich total flavonoids from Epimedium koreanum Nakai (EKN). The 18 columns were divided into 6 zones, and the principle of a dynamic series of three columns was adopted for each zone to achieve continuous automatic separation and enrichment of total flavonoids under the control of a logic control valve. The CCS separation conditions were established based on single-column chromatography and a theoretical calculation model of the CCS. By means of the self-designed device and method, 485.11±3.16 g of total flavonoids were isolated from 16.2 kg of EKN. It is worth noting that the total content of 18 types of flavonoids in the samples enriched by the CCS was increased from 2.84±0.07% to 88.29±0.22%, the total recovery rate was 92.20±0.38%, and the RSD of each flavonoid was less than 5.0%. Furthermore, compared with single-column chromatography filled with the same volume of chromatography filler, the entire process saved about 2/3 of the mobile phase usage. In summary, the developed device and method could efficiently and continuously enrich total flavonoids from EKN with high-content and low mobile phase usage and would have a wide application prospect in the separation and enrichment of natural products. [ABSTRACT FROM AUTHOR]

Transition-metal carbides have been advocated as the promising alternatives to noble-metal platinum-based catalysts in electrocatalytic hydrogen evolution reaction over half a century. However, the effectiveness of transition-metal carbides catalyzing hydrogen evolution in high-pH electrolyte is severely compromised due to the lowered proton activity and intractable alkaline-leaching issue of transition-metal centers. Herein, on the basis of validation of molybdenum-carbide model-catalyst system by taking advantage of surface science techniques, Mo2C micro-size spheres terminated by Al3+ doped MoO2 layer exhibit a notable performance of alkaline hydrogen evolution with a near-zero onset-potential, a low overpotential (40 mV) at a typical current density of 10 mA/cm2, and a small Tafel slope (45 mV/dec), as well as a long-term stability for continuous hydrogen production over 200 h. Advanced morphology and spectroscopy characterizations demonstrate that the local -Al-OH-Mo- structures within Al-MoO2 terminations serve as strong Brønsted acid sites that accelerate the deprotonation kinetics in alkaline HER process. Our work paves an interesting termination-acidity-tailoring strategy to explore cost-effective catalysts towards water electrolysis and beyond. Exploring low-cost, efficient catalysts to replace platinum is crucial for electrocatalytic hydrogen generation. Here, the authors report a termination-acidity strategy that boosts the activity of molybdenum carbides, achieving a low overpotential and sustaining hydrogen generation for over 200 h. [ABSTRACT FROM AUTHOR]

In environmental sciences, comprehending the movement of subsurface contaminants is crucial for formulating effective remediation measures. The self‐potential (SP) method has become a common tool for delineating landfill contamination plumes. Contaminant diffusion or migration represents dynamic processes, with corresponding SP responses evolving over time. However, conventional SP interpretation approaches have predominantly relied on static single‐frame inversion, overlooking the temporal correlation in time‐series SP data and resulting in cumulative errors. To tackle this challenge, we introduce a novel method for time‐lapse inversion of SP data leveraging particle filtering. This approach recursively refines the priori state model through posteriori observations to achieve precise estimations of dynamic models. Specifically, a spherical polarization model is deployed to establish the state equations of underground contaminant diffusion and transport models, whereas the observation model is derived through forward modeling. The proposed method is validated using two synthetic examples and one lab‐measured dataset. The findings demonstrate the efficacy of the time‐lapse inversion algorithm in precisely estimating dynamic models, outperforming static single‐frame inversion based on the particle swarm optimization algorithm. The posteriori distribution of particles approximates a bell‐shaped distribution, with the true state closely positioned near the peak probability. Therefore, we affirm that conducting time‐lapse inversion of time‐series SP data through particle filtering is an effective and dependable approach for accurately estimating dynamic model states. [ABSTRACT FROM AUTHOR]

Lithium (Li)‐morphology and solid electrolyte interphase (SEI) are among the most significant performance regulators in Li‐metal batteries (LMBs). While both Li‐morphology and SEI composition play key roles in the cyclability of LMBs, less is understood about the individual contributions of each factor to overall Li reversibility, particularly at a practical current density (1 mA cm−2) at which the kinetics of both factors are not naturally separated. Herein, an interface engineering approach is introduced to deconvolute the impacts of Li‐morphology and SEI composition on battery performance. By using interfacial nanofilms with differing resistivity (resistive HfO2 versus conductive ZnO), the morphology of Li is varied, and by virtue of similar acidic character of the nanofilms, the formation of anion‐rich SEIs is maintained. It is established that although the surface acidity of the thin films enables preformation of a more anion‐rich SEI, it is not preserved after Li plating. It is further shown that resistance‐controlled, low‐surface‐area Li‐morphology exhibits up to threefold increase in stable cycle life when tested in multiple electrolytes. Overall, these findings explain why Li‐morphological control is more advantageous for performance improvement than preformed SEI modulation due to the inherent challenges in SEI preservation. [ABSTRACT FROM AUTHOR]

This study aimed to explore psychological problems and related factors among frontline primary healthcare workers who belongs to community health service centers and directly provides medical security services to community residents during the COVID-19 in Shanghai. We used a cross-sectional data analysis design to investigate the anxiety and depression levels of 929 frontline healthcare staff (primary healthcare providers, nurses, village doctors, and public health workers) during the Shanghai epidemic.The prevalence of depression among frontline primary healthcare workers was 39.7% (369 cases) and that of anxiety was 30%(279 cases). There was a significant correlation between the depression symptoms and anxiety symptoms. And factors associated with depression were being female, advanced education, expecting psychological interventions, expecting vacations as a reward, and expecting financial rewards. Factors strongly associated with anxiety were being female, expecting psychological interventions, and expecting vacations as a reward. Psychological problems among frontline primary healthcare workers merit more attention during the COVID-19 outbreak, especially those who are vulnerable (e.g., females and those with an advanced education). [ABSTRACT FROM AUTHOR]

Multimodal machine learning, as a prospective advancement in artificial intelligence, endeavors to emulate the brain's multimodal learning abilities with the objective to enhance interactions with humans. However, this approach requires simultaneous processing of diverse types of data, leading to increased model complexity, longer training times, and higher energy consumption. Multimodal neuromorphic devices have the capability to preprocess spatio‐temporal information from various physical signals into unified electrical signals with high information density, thereby enabling more biologically plausible multimodal learning with low complexity and high energy‐efficiency. Here, this work conducts a comparison between the expression of multimodal machine learning and multimodal neuromorphic computing, followed by an overview of the key characteristics associated with multimodal neuromorphic devices. The bio‐plausible operational principles and the multimodal learning abilities of emerging devices are examined, which are classified into heterogeneous and homogeneous multimodal neuromorphic devices. Subsequently, this work provides a detailed description of the multimodal learning capabilities demonstrated by neuromorphic circuits and their respective applications. Finally, this work highlights the limitations and challenges of multimodal neuromorphic computing in order to hopefully provide insight into potential future research directions. [ABSTRACT FROM AUTHOR]

By free radical polymerizing methylacrylylethyl trimethyl ammonium chloride (DMC), styrene (ST), and methoxy polyethylene glycol acrylate (MPEGA), a novel type of hydrophilic polymer antistatic agent (PDSM) was created. By utilizing FT-IR and 1H NMR, the structure and properties of the PDSM copolymer were investigated. By using the melt blending approach, composites made of ABS (acrylonitrile-styrene-butadiene copolymer)/PDSM were generated. The composites' mechanical characteristics and surface resistivity were measured. The results indicated that PDSM was evenly dispersed on the inner surface of ABS resin, resulting in a continuous conductive network, and serving the intended function of long-lasting antistatic. The surface resistance of ABS composites could be greatly decreased using the PDSM copolymer antistatic agent. Surface resistivity of ABS/PDSM composites were around 109-1010 Ω when the proportion of PDSM copolymer was up to 15 wt%. As MPEGA concentration increased, the surface resistivity of ABS/PDSM materials declined because MPEGA comprised hydrophilic ether bonds and flexible side chains. [ABSTRACT FROM AUTHOR]

The combination of cold deformation and solution aging is an important technological route for the bar processing of superalloy fasteners. The microstructure evolution and mechanical properties are intimately related to the process parameters. In this study, we systematically elucidate the mechanical properties and microstructure evolution of Fe-15Cr-25Ni alloys in different treatment processes and conduct in-depth analysis of the synergistic strengthening mechanism of fine-crystal strengthening, second-phase strengthening, and work hardening on Fe-15Cr-25Ni alloys. The results show that the tensile strength and yield strength at room temperature increase with the increase in grain refinement and dislocation density but decrease with the increase in elongation. After solid-solution treatment, most of the precipitates dissolve into the matrix, and the dislocation density is greatly reduced, resulting in a decrease in strength and an increase in plasticity. After aging, a large amount of γ′ phase was precipitated. Due to the two strengthening effects of dislocation strengthening and second-phase strengthening, the strength of the aging state is more improved than that of the cold-drawing state. The purpose of this study is to provide valuable insights for the industrial production of Fe-15Cr-25Ni superalloys. [ABSTRACT FROM AUTHOR]

To investigate deep Earth information, researchers often utilize geomagnetic observatories and satellite data to obtain the conversion function of geomagnetic sounding, C-response data, and employ traditional inversion techniques to reconstruct subsurface structures. However, the traditional gradient-based inversion produces geophysical models with artificial structure constraint enforced subjectively to guarantee a unique solution. This method typically requires the model parameterization knowledge a priori (e.g., based on personal preference) without uncertainty estimation. In this paper, we apply an efficient trans-dimensional (trans-D) Bayesian algorithm to invert C-response data from observatory and satellite geomagnetic data for the electrical conductivity structure of the Earth's mantle, with the model parameterization treated as unknown and determined by the data. In trans-D Bayesian inversion, the posterior probability density (PPD) represents a complete inversion solution, based on which useful inversion inferences about the model can be made with the requirement of high-dimensional integration of PPD. This is realized by an efficient reversible-jump Markov-chain Monte Carlo (rjMcMC) sampling algorithm based on the birth/death scheme. Within the trans-D Bayesian algorithm, the model parameter is perturbated in the principal-component parameter space to minimize the effect of inter-parameter correlations and improve the sampling efficiency. A parallel tempering scheme is applied to guarantee the complete sampling of the multiple model space. Firstly, the trans-D Bayesian inversion is applied to invert C-response data from two synthetic models to examine the resolution of the model structure constrained by the data. Then, C-response data from geomagnetic satellites and observatories are inverted to recover the global averaged mantle conductivity structure and the local mantle structure with quantitative uncertainty estimation, which is consistent with the data. [ABSTRACT FROM AUTHOR]

The self-potential (SP) method is a sensitive geophysical technique to locate seafloor polymetallic sulfide deposits. Reasonable SP forward modeling can provide a good foundation for the inversion and interpretation of the measured data. Based on the mirror image theory, we proposed a method to derive the three-dimensional analytical solution of the SP generated by regularly polarized bodies in layered media, which is explained in detail within the context of the models. We discussed the analytical solutions for different types of layered models, considering variations in the number of layers and the distribution of sources. A lab-based oxidation–reduction experiment was conducted to record SP data. These data are used to simulate the SP generated by seafloor massive sulfide (SMS) deposits and validate the previous analytical solution. The result shows that the measured SP data match the analytical solution well, demonstrating the correctness of the proposed method and the corresponding analytical solution. This approach is significant for achieving fast and precise forward modeling and inversion in SMS explorations. [ABSTRACT FROM AUTHOR]

Online reviews are playing an increasingly important role in consumers' online shopping decisions. Studies on investigating the influencing factors of review helpfulness have been conducted extensively in recent years. Previous studies have proved the positive relationship between review characteristics and review helpfulness, for instance, review depth, review valence, image assistance, and identity disclosure. While, research has neglected the effect of presentation format on review helpfulness, especially its combined effect with other review characteristics. This study adopts online review data to examine how presentation format affects review helpfulness with the influence of word count and the number of responses. Besides, this study also reveals how presentation format moderates the effect of word count and the number of responses on review helpfulness across two product types. The results indicate that video-based reviews are perceived as more helpful than other formats. However, the number of responses is less important for video-based reviews, especially for search products. Moreover, word count of image-based reviews is less influential compared to text-based reviews on review helpfulness. It suggests that consumers may ignore the textual information when images enhance reviews. At last, the theoretical contributions, the practical implications, and limitations are discussed. [ABSTRACT FROM AUTHOR]

Manipulation C-C coupling pathway is of great importance for selective CO2 electroreduction but remain challenging. Herein, two model Cu-based catalysts, by modifying Cu nanowires with Ag nanoparticles (AgCu NW) and Ag single atoms (Ag1Cu NW), respectively, are rationally designed for exploring the C-C coupling mechanisms in electrochemical CO2 reduction reaction (CO2RR). Compared to AgCu NW, the Ag1Cu NW exhibits a more than 10-fold increase of C2 selectivity in CO2 reduction to ethanol, with ethanol-to-ethylene ratio increased from 0.41 over AgCu NW to 4.26 over Ag1Cu NW. Via a variety of operando/in-situ techniques and theoretical calculation, the enhanced ethanol selectivity over Ag1Cu NW is attributed to the promoted H2O dissociation over the atomically dispersed Ag sites, which effectively accelerated *CO hydrogenation to form *CHO intermediate and facilitated asymmetric *CO-*CHO coupling over paired Cu atoms adjacent to single Ag atoms. Results of this work provide deep insight into the C-C coupling pathways towards target C2+ product and shed light on the rational design of efficient CO2RR catalysts with paired active sites. Manipulating the carbon-carbon coupling pathway in CO2 electroreduction is vital yet challenging. Here, by studying two model copper-based catalysts with distinct ethylene and ethanol selectivity, authors investigate the mechanistic origins for symmetric and asymmetric carbon-carbon coupling. [ABSTRACT FROM AUTHOR]

A novel static model of planetary roller screw mechanisms (PRSMs) is proposed to obtain the load distribution over threads by an energy method. The energy method consists of the structural potential energy and an optimization problem. The potential energy is calculated by structural discretization. And the optimization problem, whose objective is the structural potential energy, is obtained by combining the principle of minimum potential energy with the forces balance constraints. The load distribution is the result of the optimization problem. A finite element model is established for validation. Compared with previous models, the proposed model has lower complexity and higher precision. To further verify the reliability and practicability of the proposed model, effects of the nut position, shaft diameter, and number of roller threads on the load distribution are analyzed based on the proposed model. The results show that the nut position has little influence on the load distribution. The shaft diameter and number of roller threads significantly impact the load distribution. [ABSTRACT FROM AUTHOR]

Electrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery. [ABSTRACT FROM AUTHOR]

Electrooxidation of biomass‐derived glycerol which is regarded as a main byproduct of industrial biodiesel production, is an innovative strategy to produce value‐added chemicals, but currently showcases slow kinetics, limited Faraday efficiency, and unclear catalytic mechanism. Herein, we report high‐efficiency electrooxidation of glycerol into formate via a Cu doped NiCo alloy catalyst supported on nickel foam (Cu−NiCo/NF) in a coupled system paired with nitrate reduction. The designed Cu−NiCo/NF delivers only 1.23 V vs. RHE at 10 mA cm−2, and a record Faraday efficiency of formate of 93.8 %. The superior performance is ascribed to the rapid generation of NiIII−OOH and CoIII−OOH species and favorable coupling of surface *O with reactive intermediates. Using Cu−NiCo/NF as a bifunctional catalyst, the coupled system synchronously produces NH3 and formate, showing 290 mV lower than the coupling of hydrogen evolution reaction, together with excellent long‐term stability for up to 144 h. This work lays out new guidelines and reliable strategies from catalyst design to system coupling for biomass‐derived electrochemical refinery. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Agricultural water consumption security is crucial for maintaining food production stability. Aiming to investigate water consumption efficiency and objectives in agricultural and non-agricultural sectors, we adopted a Budyko-analogous framework to establish an optimal water allocation model based on the maximum water utilization benefits principle. The proposed Budyko framework was verified through its application in Anhui Province, China, and the difference in water utilization efficiencies among different regions was discussed. The research findings can be concluded as follows: (1) during 2011–2020, the provincial agricultural productive loss caused by per-unit water shortage was lower compared to non-agricultural sectors, and this trend was adaptive in the south but totally opposite in the north; (2) the guaranteed level of agricultural water consumption was higher compared to non-agricultural sectors in the north due to the predominance of agricultural production but totally contrary in the south. Overall, the above findings are consistent with the actual industrial structure of Anhui Province. [ABSTRACT FROM AUTHOR]

This paper reports a novel material consisting of derivatives of coconut shell carbon and metal–organic skeleton (MOF) which could be used as supercapacitors electrode material. Coconut shell carbon@ZIF-67 derivative (designated CC@ZIF-67-D) materials were prepared via hydrothermal method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The results demonstrated that the CC@ZIF-67-D was successfully prepared were obtained after calcination, and the ZIF-67-D exhibited uniform distribution on the surface of the coconut shell carbon (noted CC). Electrochemical tests were conducted using an electrochemical workstation and it was found that the specific capacitance of CC as an electrode material was determined to be 96.6 F/g at a current density of 0.1 A/g. The specific capacitance of the capacitor prepared using CC@ZIF-67-D derivative composite was found to be 137.8 F/g. The supercapacitor exhibits a high energy density of 46.2 Wh/kg at the power density of 450 W/kg. This work presents a novel material that has the potential application in energy storage devices. Furthermore, it offers a promising and excellent strategy for the preparation of electrode materials with high performance and good cycling stability. [ABSTRACT FROM AUTHOR]

Cracks are a common rock microstructure and have a large effect on elastic properties during wave propagation. The fluid flow between a crack and its adjacent pore space can cause wave attenuation and dispersion. In this work, we introduce a crack connectivity parameter which is meant to improve the expression of local flow by weighting the contributions of fully connected and isolated cracks. We then update the analytical expression for frequency-dependent moduli by modifying the boundary conditions of the linearized Navier–Stokes equation and mass conservation equation. The proposed model contains the effect of cracks and stiff pores, in which the attenuation and dispersion are determined by squirt-flow and stiff-pore relaxations. The resulting model shows the squirt-flow relaxation frequency depends on not only the crack aspect ratio but also the crack connectivity. However, their contributions are different. The crack connectivity has little effect on the attenuation amplitude of shear modulus, but affects the attenuation amplitude of bulk modulus when multiple sets of cracks exist in the rock. The attenuation frequency band is also affected by the crack connectivity. As the crack connectivity deteriorates, the attenuation peak moves to low frequencies. In addition, by comparing the crack connectivity with the fluid viscosity coefficient, it is observed that the crack connectivity only affects the attenuation frequency band of cracks, whereas the fluid viscosity coefficient affects the attenuation frequency bands of cracks and stiff pores simultaneously. Thus, the introduction of crack connectivity is a supplement to the theoretical model of cracked fluid-saturated rocks. It helps understand the local fluid flow induced by seismic waves and provides a reasonable variation analysis of moduli and attenuation, especially for tight reservoirs. [ABSTRACT FROM AUTHOR]

In this paper, a 150-µm-thick flexible γ-Al2O3 nanofiber separator with the tensile strength of 0.22 MPa was prepared from the low-cost aluminum chloride hydroxide/polyvinyl alcohol (PVA)/water precursor materials by electrospinning method. The resultant separator with 3D interconnection nanostructure revealed fiber diameters in the range of 200 to 500 nm. The specific surface area, porosity, and electrolyte uptake of γ-Al2O3 nanofiber separator are 31.5 m2/g, 55%, and 1021%, higher than that of commercial polypropylene (PP) separator and glass fiber (GF) separator. The supercapacitor assembled with the γ-Al2O3 nanofiber separator exhibited a high discharge specific capacitance of 93 F/g at the current density of 1A/g, and there is almost no capacity decay after 10,000 cycles. The energy density of supercapacitor assembled with γ-Al2O3 nanofiber separator is 31.7 Wh/kg at the power density of 562.6 W/kg. Meanwhile, the rate performance of the supercapacitor is improved significantly due to the existence of porous structure and low ion diffusion resistance (0.78 Ω) of γ-Al2O3 nanofiber separator. In addition, the thermal performance of the γ-Al2O3 nanofiber separator is also excellent, which has almost no shrinkage at the temperature of 200 °C and cannot be ignited. Therefore, the obtained γ-Al2O3 nanofibers could serve as a promising alternative separator for a new generation of safe, high-power supercapacitors. [ABSTRACT FROM AUTHOR]

The burgeoning advancement of information technology has engendered a discernible surge in the examination of neuromorphic devices, notably drawing broader attention to artificial vision systems endowed with sensory recognition capabilities. Current photoelectric synapse devices employed in artificial vision systems are generally well‐suited for well‐illuminated conditions, yet exhibit diminished sensitivity in weak‐light scenarios, resulting in a pronounced deterioration of recognition accuracy. Here, an ultrasensitive photoelectric synaptic transistor based on negative quantum capacitance effect resulted from the 2D semi‐metallic graphene layer that partially enclosed within the gate dielectric layer, which manifests a noteworthy reduction in device control voltage and exhibits perception and storage capabilities for weak light of 39.4 nW cm−2 with detectivity above 1016 cm Hz1/2 W−1 is demonstrated. The voltage amplification effect and the concomitant formation of an equivalent local electrostatic field induced by the negative quantum capacitance effect engenders a robust programmable synaptic plasticity for extremely weak light by modifying the control gate. These results represent the inaugural integration of the negative quantum capacitance effect into optoelectronic devices and furnish a robust hardware foundation for developing vision systems in weak‐light environments. [ABSTRACT FROM AUTHOR]

The safety and efficiency of lithium‐ion batteries (LIBs) suggest a promising future for this technology, particularly in the automobile industry. However, thermal runaway—wherein a LIB undergoes an uncontrollable increase in temperature that may result in smoke, fire, or explosion—represents an important and widely studied failure type. Since the electrodes of LIBs are manufactured from porous composite materials, their heterogeneity can significantly influence the effective material characteristics and microscale behaviors of LIBs during operation. Microstructure geometric and electrochemical–thermal models are typically used to investigate these impacts. Herein, a microstructure geometric model is constructed of LIB's electrodes. A virtual multiphysics model is used to simulate the overcharging thermal runaway condition. The model's accuracy is validated through real‐world experiments. The model shows greater accuracy compared to the result from a conventional homogeneous geometric model and better reflects the heterogeneous internal phenomenon. The model is applied to a variable analysis in order to investigate how the varying heterogeneity of the cathode's porosity impacts the cell during overcharging thermal runaway behavior. Our results indicate that decreasing porosity heterogeneity at the cathode may delay thermal runaway, owing to the heterogeneous impact on particle diffusion behaviors and the side reaction rate. [ABSTRACT FROM AUTHOR]

The failure modes of complex systems are often highly dependent. Aiming at the reliability analysis of engineering systems with multiple failure modes, an efficient surrogate model for system reliability with multiple failure modes is proposed, namely, the Copula Adaptive Kriging surrogate model (CAKSM). First, the initial Kriging model is established based on the initial samples. In order to select more effective added samples to update the Kriging model, a new learning function, namely, Copula Unites with Expected Improvement Function (CUEIF), is established. The function can make a reasonable sample selection by considering the failure correlation. Then, based on the optimal Copula function, the reliability data of each failure mode are coupled and analyzed. In order to adapt to various computing scales, regularization is introduced to improve the prediction speed of the surrogate model, and the probability density function of each performance function is obtained by introducing nonparametric kernel density estimation. Finally, the effectiveness of the CAKSM method and the learning function CUEIF is verified through four examples. [ABSTRACT FROM AUTHOR]

In China, significant progress has been made in the exploration and development of coalbed methane (CBM) in medium- to high-rank coals. However, the exploration and development potential of CBM in low-rank coals in the Zhalainuoer coalfield is unknown. In this study, various testing methods were utilized, including low temperature N2/CO2 adsorption, field emission scanning electron microscopy, and nuclear magnetic resonance, to investigate the pore structure characteristics of low-rank coals in the Zhalainuoer coalfield, so as to further evaluate the occurrence space of CBM therein. The results revealed that the prevalent pore types in the low-rank coals were "ink bottle" shaped pores and semi-closed pores, and micropores provide the main specific surface area (SSA) and total pore volume (TPV). Moreover, there is no significant correlation between vitrinite content and fractal dimension, while pore SSA and TPV are correlated positively with D1 but negatively with D2. The coalification degree significantly impacts the pore characteristics of the coal reservoirs. With coalification degree increasing, the SSA and TPV of micropores and transition pores generally exhibited a pattern of initially decreasing and then increasing. These research findings establish a theoretical foundation for the exploration and development of CBM in the Zhalainuoer coalfield. [ABSTRACT FROM AUTHOR]

Simple Summary: Diabetic ketosis and ketoacidosis are severe and potentially life-threatening complications of diabetes mellitus in cats. Affected patients require intensive glucose monitoring. This monitoring is most commonly performed by using handheld portable blood glucose meters that require a sample of capillary blood. Glucose monitoring can be stressful for patients and veterinary personnel. A novel continuous flash glucose monitoring system (FreeStyle Libre 2.0 Abbott®) eliminates the need for frequent capillary blood sampling. In this study, however, the latest FreeStyle Libre 2.0 Abbott® measured significantly lower glucose concentrations than the handheld blood glucose meter, both in well-hydrated and dehydrated cats. False low measurements do not lead to insulin overdosing, which can be detrimental to the patient, but may nonetheless lead to suboptimal insulin management. Additionally, the agreement between the FreeStyle Libre 2.0 Abbott® and a handheld device varied significantly between cats. Cats with diabetic ketosis or ketoacidosis DK(A) require intensive glucose monitoring. The aim of this study was to assess the agreement between a portable blood glucose meter (PBGM) and a flash glucose monitoring system (FGMS; FreeStyle Libre 2.0 Abbott®) measuring interstitial glucose in cats with DK(A). Ten client-owned cats with naturally occurring DK(A) were prospectively enrolled. Glucose concentrations were assessed with both methods every 1–3 h until resolution of DK(A), and every 4–8 h thereafter. While the median FGMS measured glucose concentration (14.3 mmol/L) was significantly lower than the median PBGM measured glucose concentration (19 mmol/L) (p < 0.001), the overall correlation between the FGMS and PBGM was high (r = 0.88; p < 0.001). In the Parkes error grid analysis, 98.3% of measurements fell in zones A and B. Bland–Altman plot analysis demonstrated that in the low glycaemic range (BG < 5.5 mmol/L), 50% of FGMS measurements deviated more than ±0.83 mmol/L, and in the high glycaemic range (BG > 5.5 mmol/L), 81% of results deviated >15% from the PBGM measurements. There was significant inter-individual variation in the difference between glucose concentrations measured by the FGMS and PBGM (p < 0.001). In spite of being more easily tolerated and easier to use, currently this method cannot be recommended for routine monitoring of cats with DK(A). [ABSTRACT FROM AUTHOR]

Clematis serratifolia has high medicinal and ornamental value. In this study, we characterize and report, for the first time, the complete chloroplast genome sequence of C. serratifolia based on high-throughput sequence dates. The whole chloroplast genome of C. serratifolia is a circular molecule of 159,648 bp in length, consisting of a large single-copy (LSC) region of 79,394 bp, a small single-copy (SSC) region of 18,112 bp, and two inverted repeat (IR) regions of 31,071 bp. The overall GC content of the chloroplast genome is 38%, while that in the LSC, SSC, and IR regions is 36.3%, 31.3%, and 42.1%, respectively. The chloroplast genome of C. serratifolia contains 133 genes, including 89 coding genes, 8 ribosomal RNAs, and 36 transfer RNAs. Among them, 14 protein-coding genes have a single intron, and 2 genes have two introns. The phylogenetic analysis showed a close relationship between C. serratifolia and C. heracleifolia. [ABSTRACT FROM AUTHOR]

Thermal management is essential for maintaining optimal performance across various applications, including personal comfort, electronic systems and industrial processes. Thermal-management fibers and textiles have emerged as innovative solutions to manipulate heat transport, storage and conversion efficiently. This review explores recent advancements in material innovations in this field. We summarize the novel fibers and textiles designed for controlling heat transport through different pathways, progress in developing phase-change-material-based fibers and textiles for heat storage regulation, and application of photothermal conversion, Joule heating and thermoelectric effect as energy conversion routes in advanced fibers and textiles. Furthermore, we discuss the challenges and future perspectives of this field. It is believed that ongoing research and development promise to bring about innovative thermal-management solutions catering to demands across multiple sectors. [ABSTRACT FROM AUTHOR]

CMOS image sensors in optical payloads are susceptible to single-event effects when irradiated by high-energy protons from the spatial radiation environment. Single-event transients in images primarily manifest as bright spots, and the characteristics of transient bright spots generated under different incident conditions exhibit some differences. In this study, we conducted proton irradiation experiments on CMOS image sensors at different energy levels and incident angles. The characteristics of single-event transient bright spots generated under various incident conditions were extracted and analysed in detail. Furthermore, the abnormal phenomena of different functional modules of CMOS image sensors observed during proton irradiation experiments were investigated. The results of this study establish the foundation for classifying the detected targets and transient bright spots, indicating that the validation of CMOS image sensor radiation reliability should account for functional abnormalities resulting from high-energy proton irradiation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taste and odor (T&O) compounds have emerged as crucial parameters for assessing water quality. Therefore, identifying effective methodologies for the removal of these compounds is imperative. In this study, an effective approach utilizing laccase assisted by a micro-electric field was developed for the degradation of 2-methylisoborneol (2-MIB). For this purpose, the optimal conditions for the laccase-catalyzed degradation of 2-MIB were determined, and they were pH 4.0, 25 °C, 150 rpm, 0.1 U/mL of laccase, and 200 ng/L of 2-MIB. Under these specified conditions, the degradation efficiency of 2-MIB was approximately 78% after a 4 h reaction period. Subsequently, the introduction of an electric field yielded a synergistic effect with the enzyme for 2-MIB degradation. At an electric current intensity of 0.04 A over a 4 h duration, the degradation efficiency increased to 90.78%. An analysis using SPME-GC/MS provided information on the degradation intermediates of 2-MIB resulting from laccase-catalyzed degradation, electrocatalytic degradation, and micro-electric-assisted laccase degradation. The potential degradation pathways of 2-MIB illustrated that these three methods result in common degradation products, such as capric aldehyde, nonylaldehyde, and 2-ethylhexanol, and their final products include 3-pentanone, acetone, and 2-butanone. This study provides an enzyme–electrochemical method for the efficient and rapid degradation and removal of 2-MIB. The strategy of laccase catalysis assisted by a micro-electric field has good potential for the removal of pollutants from the natural environment. [ABSTRACT FROM AUTHOR]

The piston ring and cylinder liner (PRCL) system in larger-bore low-speed marine engines frequently experiences scuffing failures, which significantly decrease the engine reliability. To understand this failure mechanism, a scuffing failure model subjected to the PRCL system was developed considering multidisciplinary coupling effects that integrate asperity contact, hydrodynamic lubrication, tribochemistry reactions, thermal effects, friction, and surface wear. The impacts of large-scale deformation and gas-combustion mode on the scuffing performances of the PRCL system were examined. The key findings indicate that the larger-scale liner deformation can markedly reduce oil film thickness and exacerbate local asperity contact, influencing the evolution of the tribofilm by increasing the removal process. Under gas-combustion mode, the oil film thickness is even lower, and the asperity contact pressure further increases due to a more starved lubrication state and higher combustion temperature. This leads to tribofilm breakdown and severe wear near the ring opening area, which are aligning with the full-scale experimental results with scuffing failure. [ABSTRACT FROM AUTHOR]

Star sensors play a crucial role as high-precision optical attitude navigation devices in satellite attitude control systems. The CMOS image sensor is an important component of the imaging system of the star sensor and experiences performance degradation due to the total ionizing dose effect and displacement damage effect in the radiation environment of its long-term operational workspace. As a result, the detection capability and attitude positioning accuracy of the star sensor gradually deteriorate. The performance of CMOS image sensors can be partially restored after annealing but the impact on the performance of star sensors is unclear. This study conducted 100 MeV proton irradiation experiments with different fluences on CMOS image sensors and performed room temperature and high temperature annealing treatments. By testing and analyzing the performance of star sensors equipped with irradiated and different annealing treatments on CMOS image sensors, the impact mechanism of CMOS image sensor radiation damage and annealing recovery on the performance variation of star sensors was obtained. This study provides theoretical support for reliability of long-term in-orbit star sensors. [ABSTRACT FROM AUTHOR]

Background: The National Chest Pain Center Program (NCPCP) is a nationwide, quality enhancement program aimed at raising the standard of care for patients experiencing acute chest pain in China. The benefits of chest pain center (CPC) accreditation on acute coronary syndrome have been demonstrated. However, there is no evidence to indicate whether CPC accreditation improves outcomes for patients with acute aortic dissection (AAD). Methods: We conducted a retrospective observational study of patients with AAD from 1671 hospitals in China, using data from the NCPCP spanning the period from January 1, 2016 to December 31, 2022. The patients were divided into 2 groups: pre-accreditation and post-accreditation admissions. The outcomes examined included in-hospital mortality, misdiagnosis, and Stanford type A AAD surgery. Multivariate logistic regression was employed to explore the relationship between CPC accreditation and in-hospital outcomes. Furthermore, we stratified the hospitals based on their geographical location (Eastern/Central/Western regions) or administrative status (provincial/non-provincial capital areas) to assess the impact of CPC accreditation on AAD patients across various regions. Results: The analysis encompassed a total of 40,848 patients diagnosed with AAD. The post-accreditation group exhibited significantly lower rates of in-hospital mortality and misdiagnosis (12.1% vs. 16.3%, P < 0.001 and 2.9% vs. 5.4%, P < 0.001, respectively) as well as a notably higher rate of Stanford type A AAD surgery (61.1% vs. 42.1%, P < 0.001) compared with the pre-accreditation group. After adjusting for potential covariates, CPC accreditation was associated with substantially reduced risks of in-hospital mortality (adjusted OR 0.644, 95% CI 0.599–0.693) and misdiagnosis (adjusted OR 0.554, 95% CI 0.493–0.624), along with an increase in the proportion of patients undergoing Stanford type A AAD surgery (adjusted OR 1.973, 95% CI 1.797–2.165). Following CPC accreditation, there were significant reductions in in-hospital mortality across various regions, particularly in Western regions (from 21.5 to 14.1%). Moreover, CPC accreditation demonstrated a more pronounced impact on in-hospital mortality in non-provincial cities compared to provincial cities (adjusted OR 0.607 vs. 0.713). Conclusion: CPC accreditation is correlated with improved management and in-hospital outcomes for patients with AAD. [ABSTRACT FROM AUTHOR]

Reconfigurable coupled-resonator elastic waveguides are formed using defects composed of threaded rods, fixed with nuts and attached to a perforated two-dimensional phononic crystal slab. The resonant frequency of the defect can be tuned continuously within a complete phononic bandgap by adjusting the length of the threaded rod. Straight waveguides are formed from a line of defects. Phononic circuits are created by coupling three parallel straight waveguides. Through precise manipulation of the length of the threaded rod assembly, frequency demultiplexing of Lamb waves is achieved. Numerical and experimental results are found to be in good agreement. This work is of significance for the practical design of phononic devices including reconfigurable circuits. [ABSTRACT FROM AUTHOR]

Fatty acyl‐CoA reductase (FAR) is one of the key enzymes, which catalyses the conversion of fatty acyl‐CoA to the corresponding alcohols. Among the FAR family members in the brown planthopper (Nilaparvata lugens), NlFAR7 plays a pivotal role in both the synthesis of cuticular hydrocarbons and the waterproofing of the cuticle. However, the precise mechanism by which NlFAR7 influences the formation of the cuticle structure in N. lugens remains unclear. Therefore, this paper aims to investigate the impact of NlFAR7 through RNA interference, transmission electron microscope, focused ion beam scanning electron microscopy (FIB‐SEM) and lipidomics analysis. FIB‐SEM is employed to reconstruct the three‐dimensional (3D) architecture of the pore canals and related cuticle structures in N. lugens subjected to dsNlFAR7 and dsGFP treatments, enabling a comprehensive assessment of changes in the cuticle structures. The results reveal a reduction in the thickness of the cuticle and disruptions in the spiral structure of pore canals, accompanied by widened base and middle diameters. Furthermore, the lipidomics comparison analysis between dsNlFAR7‐ and dsGFP‐treated N. lugens demonstrated that there were 25 metabolites involved in cuticular lipid layer synthesis, including 7 triacylglycerols (TGs), 5 phosphatidylcholines (PCs), 3 phosphatidylethanolamines (PEs) and 2 diacylglycerols (DGs) decreased, and 4 triacylglycerols (TGs) and 4 PEs increased. In conclusion, silencing NlFAR7 disrupts the synthesis of overall lipids and destroys the cuticular pore canals and related structures, thereby disrupting the secretion of cuticular lipids, thus affecting the cuticular waterproofing of N. lugens. These findings give significant attention with reference to further biochemical researches on the substrate specificity of FAR protein, and the molecular regulation mechanisms during N. lugens life cycle. [ABSTRACT FROM AUTHOR]

Wind turbine generator output cables are subjected to alternating torsional loads during long-term operation, combined with electrothermal stress, which may lead to insulation failure and other serious issues. Currently, the electrothermal aging mechanism under torsional stress is not fully understood. This study explores the synergistic degradation mechanism of electrothermal aging and nonlinear torsion by constructing a multi-stress aging test platform in the laboratory environment. This study involved accelerated aging tests with thermal, electrothermal, and electrothermal–torsional alternating stresses. The aged cable samples were analyzed for their physical and chemical properties using differential scanning calorimetry and Fourier transform infrared spectroscopy, while dielectric spectroscopy and mechanical tests were employed to evaluate their dielectric and mechanical performance. The results indicate that torsional stress induces physical changes at the molecular level in the ethylene–propylene rubber (EPR), leading to reduced strength, hardening, and increased brittleness, resulting in decreased mechanical strength. In addition, torsional stress promotes oxidation reactions and chain scission processes in the insulation layer, reducing crystallinity and causing a decline in mechanical performance. Increased oxidation and chain scission reactions result in an increase in polar groups, leading to an increase in the dielectric loss factor of the EPR. The findings of this study provide valuable insights for the design, manufacturing, and operational monitoring of wind turbine generator output cables. [ABSTRACT FROM AUTHOR]

Simple Summary: Detecting key areas in tissue samples is crucial for accurate and timely cancer diagnosis. This study focuses on using advanced deep learning techniques to analyze images of skin tumors, specifically melanoma and nevi. By training our deep learning-based model on a dataset of these images, we aimed to detect key areas in each image and simultaneously classify whether a given image shows melanoma or a benign nevus. Our method achieved an accuracy of 92.3% in classifying the images from a test set, meaning it correctly identified most cases. This approach not only helps in distinguishing between these types of skin tumors but also shows promise for broader applications in diagnosing various cancers, potentially improving clinical outcomes and reducing healthcare costs. Automated region of interest detection in histopathological image analysis is a challenging and important topic with tremendous potential impact on clinical practice. The deep learning methods used in computational pathology may help us to reduce costs and increase the speed and accuracy of cancer diagnosis. We started with the UNC Melanocytic Tumor Dataset cohort which contains 160 hematoxylin and eosin whole slide images of primary melanoma (86) and nevi (74). We randomly assigned 80% (134) as a training set and built an in-house deep learning method to allow for classification, at the slide level, of nevi and melanoma. The proposed method performed well on the other 20% (26) test dataset; the accuracy of the slide classification task was 92.3% and our model also performed well in terms of predicting the region of interest annotated by the pathologists, showing excellent performance of our model on melanocytic skin tumors. Even though we tested the experiments on a skin tumor dataset, our work could also be extended to other medical image detection problems to benefit the clinical evaluation and diagnosis of different tumors. [ABSTRACT FROM AUTHOR]

With the rapid improvement of equipment integration technology, multi-spectrum detectors are integrated into compact volumes and widely used for object detection. Confront with this challenge, it is essential to propose a strategy to design a single-layer metasurface with multi-spectrum responses in microwave and infrared ranges. In this work, we proposed a method of designing meta-atoms, which is capable of achieving functional electromagnetic response at microwave and infrared individually. As a demonstration, a metasurface with four different occupation ratios and coding permutation features is designed, fabricated, and tested. In the microwave band, the pixel meta-atom is designed to realize highly efficient cross-polarization conversion between 5.0 and 10.0 GHz, which shows the metasurface can behave as ultra-low Radar Cross Section (RCS) reflectors in the working band; In the infrared band, different occupation ratio of meta-atoms are designed to realize the infrared emissivity from 0.60 to 0.80 in 3–14 μm, which can be used to exhibit digital infrared camouflage pattern. This work promotes the ability to use single-layer design to achieve digital infrared camouflage and microwave RCS reduction simultaneously. The one-layer design is simple in geometry, simplified in process, low cost in economy, and large scale in fabrication, which can promote practical use in compatible microwave stealth and infrared camouflage. [ABSTRACT FROM AUTHOR]

Microstructural changes in conductive materials induced by electric current treatments, such as electromigration and electroplasticity, are critical in semiconductor and metal processing. However, owing to the inevitable thermal effect (Joule heating), the athermal effect on microstructural modifications remains obscure. This paper presents an approach of utilizing pre-micromachined structures, which obstruct current flow but maintain a thermal history similar to that of the matrix, effectively disentangling the thermal and athermal effects. A duplex stainless-steel material is selected to validate the feasibility of this method. Microstructural characterizations show that the athermal effect, especially the electron wind force (EWF), primarily governs the element diffusion and phase transformation in this study. Moreover, many σ phases (Cr-enriched) are precipitated in the micromachined structures, whereas no precipitation occurred in the matrix, suggesting that the directional EWF disrupts the Cr aggregation caused by Joule heating. Furthermore, we present a critical formula for determining the dimensions of micromachined structures of commonly used metallic materials. The proposed method may serve as an effective and powerful tool for unveiling the athermal effect on microstructural alterations. Understanding the impact of the athermal effect on microstructures is crucial for designing and manufacturing semiconductor and metal materials. Here, the authors propose a method using pre-micromachined structures to decouple thermal and athermal effects and experimentally validate its feasibility. [ABSTRACT FROM AUTHOR]

To effectively reveal the disaster-causing mechanism between water stress and yield loss under different drought combinations during multiple growth periods of winter wheat, based on biennial wheat drought experiments, a crop growth analysis method was used to quantitatively identify and assess wheat yield loss sensitivity. The results showed that there was a significant negative correlation between the total dry matter relative growth rate (RGR) of wheat and the daily average degree of drought stress. The average determination coefficients of logarithmic fitting for 2017 and 2018 were 0.7935 and 0.7683, respectively. Wheat dry matter accumulation differed under the different drought combination scenarios. The yield loss sensitivity response relationship between the decrease in the RGR of wheat dry matter (relative to no drought stress) and the daily average degree of drought stress could be quantitatively identified by an S-shaped curve, and the 2017 and 2018 average coefficients of determination R2 were 0.859 and 0.849, respectively. Mild drought stress at the tillering stage stimulates adaptability and has little effect on yield. The soil water content (SWC) can be controlled to 65–75% of the field water holding capacity; the SWC at the jointing and booting stage can be controlled to be higher than the field water holding capacity of 55%. The SWC was maintained at a level higher than 75% of the field water holding capacity during the heading and flowering stages and the grain-filling and milky stages to achieve a harmonization of yields and water savings. In addition, during the production process, continuous severe drought during the jointing and booting stage and the heading and flowering stage should be avoided. This study elucidates the response relationship between drought intensity and drought-induced losses from the perspective of physical genesis, provides effective irrigation guidance for regional wheat planting, lays the foundation for the construction of quantitative agricultural drought loss risk curves, and provides technical support for predicting the trend of yield losses in wheat under different drought stresses. [ABSTRACT FROM AUTHOR]

AlGaN/GaN high-electron-mobility transistors (HEMTs) are widely used in high-frequency and high-power applications owing to the high two-dimensional electron gas (2DEG) concentration. However, the microscopic origin of the 2DEG remains unclear. This hinders the development of device fabrication technologies, such as threshold voltage modulation, current collapse suppression, and 2DEG concentration enhancement technologies, as well as AlGaN/GaN sensors with very high sensitivity to polar liquids. To clarify the 2DEG microscopic origin, we studied the effects of gas molecules on AlGaN/GaN surfaces through various experiments and first-principles calculations. The results indicated that the adsorption of gas molecules on the AlGaN/GaN surface is an important phenomenon, clarifying the microscopic origin of the 2DEG. This study elucidates the properties of AlGaN/GaN heterojunctions and promotes the development of new fabrication technologies for AlGaN/GaN devices. [ABSTRACT FROM AUTHOR]