Based on the density functional theory,the double half-Heusler alloys LuXCo_(2)Bi_(2)(X=V,Nb,and Ta)were studied to predict their structural,thermodynamic,thermoelectric,and optical characteristics.All the considered ...Based on the density functional theory,the double half-Heusler alloys LuXCo_(2)Bi_(2)(X=V,Nb,and Ta)were studied to predict their structural,thermodynamic,thermoelectric,and optical characteristics.All the considered alloys are thermodynamically stable and have semiconductor behavior with indirect band gaps of 0.62,0.75,and 0.8 eV for LuVCo_(2)Bi_(2),LuNbCo_(2)Bi_(2),and LuTaCu_(2)Bi_(2),respectively.The investigated compounds exhibit semiconducting behavior with energy gaps below 0.8 eV.The impact of heat and pressure on thermodynamic coefficients was evaluated,and the influence of charge carriers on the temperature-dependent properties was studied using the semi-classical Boltzmann model.The studied compounds were characterized by their low lattice thermal conductivity at room temperature and low thermal expansion coefficient.These alloys exhibit substantial absorption coefficients in the ultraviolet(UV)light region,high optical conductivity,and high reflectivity in the visible light region,making them highly appealing materials for applications in the energy and electronics sectors.展开更多
Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling ap...Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling approach enhanced by negative learning,employing a Bidirectional Long Short-Term Memory(BiLSTM)network explicitly trained to accurately reconstruct non-seismic geomagnetic signals while intentionally amplifying reconstruction errors for seismic signals.By penalizing the model for accurately reconstructing seismic anomalies,the negative learning approach effectively magnifies the differences between normal and anomalous data.This strategic differentiation enhances the sensitivity of the BiLSTM network,enabling improved detection of subtle geomagnetic anomalies that may serve as earthquake precursors.Experimental validation clearly demonstrated statistically significant higher reconstruction errors for seismic signals compared to non-seismic signals,confirmed through the Mann-Whitney U test with a p-value of 0.0035 for Root Mean Square Error(RMSE).These results provide compelling evidence of the enhanced anomaly detection capability achieved through negative learning.Unlike traditional classification-based methods,negative learning explicitly encourages sensitivity to subtle precursor signals embedded within complex geomagnetic data,establishing a robust basis for further development of reliable earthquake prediction methods.展开更多
This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes...This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes were analysed:quasi-critical(T_(r)=1.01,P_(r)=1.01),transitional(T_(r)=2.01,P_(r)=1.01),and deep supercritical(T_(r)=5.01,P_(r)=3.01).Theevolution of density,temperature,and velocity fieldswas examined to characterize the internal structure and stability of the interfacial transition layer.The evolution of density,temperature,and velocity fields highlights the competition between thermal diffusion,compressibility,andmass confinement in shaping the stability of the interfacial transition layer.Near the critical point,strong gradients and flux discontinuities emerge,consistent with known instabilities,whereas higher reduced conditions promote homogenization and stabilized transport.In the deep supercritical regime,smooth and nearly uniform fields indicate robust thermal stability.The model is validated against prior studies on droplet evaporation under supercritical and trans-critical conditions.Beyond theoretical insights,the results underline practical implications for advanced propulsion,heat transfer,and evaporation systems as well as for safe CO_(2)supercritical storage and extraction processes in energy,aerospace,pharmaceutical,and materials industries.展开更多
Lithium-ion batteries(LIBs),while dominant in energy storage due to high energy density and cycling stability,suffer from severe capacity decay,rate capability degradation,and lithium dendrite formation under low-temp...Lithium-ion batteries(LIBs),while dominant in energy storage due to high energy density and cycling stability,suffer from severe capacity decay,rate capability degradation,and lithium dendrite formation under low-temperature(LT)operation.Therefore,a more comprehensive and systematic understanding of LIB behavior at LT is urgently required.This review article comprehensively reviews recent advancements in electrolyte engineering strategies aimed at improving the low-temperature operational capabilities of LIBs.The study methodically examines critical performance-limiting mechanisms through fundamental analysis of four primary challenges:insufficient ionic conductivity under cryogenic conditions,kinetically hindered charge transfer processes,Li+transport limitations across the solidelectrolyte interphase(SEI),and uncontrolled lithium dendrite growth.The work elaborates on innovative optimization approaches encompassing lithium salt molecular design with tailored dissociation characteristics,solvent matrix optimization through dielectric constant and viscosity regulation,interfacial engineering additives for constructing low-impedance SEI layers,and gel-polymer composite electrolyte systems.Notably,particular emphasis is placed on emerging machine learning-guided electrolyte formulation strategies that enable high-throughput virtual screening of constituent combinations and prediction of structure-property relationships.These artificial intelligence-assisted rational design frameworks demonstrate significant potential for accelerating the development of next-generation LT electrolytes by establishing quantitative composition-performance correlations through advanced data-driven methodologies.展开更多
Hydrogen peroxide(H_(2)O_(2)) has been recognized as a green and nonpolluting multifunctional oxidant with extensive applications in environmental protection,metal etching,textile printing and dyeing,chemical synthesi...Hydrogen peroxide(H_(2)O_(2)) has been recognized as a green and nonpolluting multifunctional oxidant with extensive applications in environmental protection,metal etching,textile printing and dyeing,chemical synthesis and food processing.However,over 90 % of industrial H_(2)O_(2) is currently produced through the multi-step anthraquinone oxidation process,which suffers from a process with some drawbacks such as complex,high-energy consumption,and toxic byproducts emissions.Compared to the traditional anthraquinone method,artificial photosynthesis of H_(2)O_(2) using semiconductor photocatalysts has emerged as a sustainable alternative due to its use of water and O_(2) as the clean reactants and sole energy as the driving force.In recent years,metal-free photocatalysts mainly including covalent organic frameworks(COFs),covalent triazine frameworks(CTFs) and carbon nitrile(g-C_(3)N_(4)) have garnered significant interest due to their superior thermal and chemical stability,diverse synthesis methods,tunable functionality,light weight nature and non-toxicity.These materials also exhibit adjustable band structure and unique photoelectric properties.Sustainable efforts have been made to advance metal-free photocatalysts for artificial photosynthesis of H_(2)O_(2),however,a comprehensive summary of current research status on metalfree-based photocatalytic overall H_(2)O_(2) production remain scarce.This review outlines recent process in overall H_(2)O_(2) photosynthesis based on metal-free photocatalysts.First,we introduced the fundamental concepts of photocatalytic overall H_(2)O_(2) production.Then,we analyze representative studies on photocatalytic overall H_(2)O_(2) synthesis using metal-free materials.Finally,we discuss the challenges and future perspectives in this field to guide the design and synthesis of metal-free systems for H_(2)O_(2) generation.展开更多
Cu_(x)Ta_(2-x)O_(5) compositions were investigated for advanced thermoelectric and optical applications,using both simulations and experimental approaches.Density functional theory calculations were performed before t...Cu_(x)Ta_(2-x)O_(5) compositions were investigated for advanced thermoelectric and optical applications,using both simulations and experimental approaches.Density functional theory calculations were performed before the experimental observations to predict the trends of various parameters.Crystal structure analysis confirmed the presence of the orthorhombic Ta_(2)O_(5) phase in all the compositions.The composition and morphology demonstrated impurity-free contents with uniform and crack-free surfaces.Thermoelectric analysis depicted a decrease in Seebeck coefficient from 3.66??V·K^(-1)to 1.91??V·K^(-1)and an increase in the value of specific heat from 0.73 J·K^(-1)·kg^(-1)to 11.6 J·K^(-1)·kg^(-1)upon Cu incorporation in structure.The bandgap was found to reduce from 2.61 to 1.38 e V with Cu-induced electronic states.The real epsilon and static refractive index increased from 3.75 to 4.57 and from 1.93 to 2.11,respectively,with increment in Cu content.The enhanced parameters,focusing on the thermoelectric and optical responses,make these compositions potential candidates for advanced optoelectronic applications.展开更多
The paper concludes that the energy given by Einstein’s famous formula E = mc2 consists of two parts. The first part is the positive energy of the quantum particle modeled by the topology of the zero set. The second ...The paper concludes that the energy given by Einstein’s famous formula E = mc2 consists of two parts. The first part is the positive energy of the quantum particle modeled by the topology of the zero set. The second part is the absolute value of the negative energy of the quantum Schr?dinger wave modeled by the topology of the empty set. We reason that the latter is nothing else but the so called missing dark energy of the universe which accounts for 94.45% of the total energy, in full agreement with the WMAP and Supernova cosmic measurement which was awarded the 2011 Nobel Prize in Physics. The dark energy of the quantum wave cannot be detected in the normal way because measurement collapses the quantum wave.展开更多
Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses dope...Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of DyOwere examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H→~6 F). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dyion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F→~6 H, blue) and 587 nm(~4 F→~6 H, green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications.展开更多
Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates （5.32-250.0μm/s） at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus.The values of eutectic spac...Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates （5.32-250.0μm/s） at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus.The values of eutectic spacing were measured from transverse sections of the samples.The dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53,respectively.The results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the literature.Microhardness of directionally solidified samples was also measured by using a microhardness test device.The dependency of the microhardness on growth rate is found as Hv=115.64V0.13.Afterwards,the electrical resistivity （r） of the casting alloy changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300-630 K.The enthalpy of fusion （ΔH） and specific heat （Cp） for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/（g·K）,respectively by means of differential scanning calorimetry （DSC） from heating trace during the transformation from liquid to solid.展开更多
Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and ge...Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. The transmissivity of the uncon?ned aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and transverse resistance. The relationship established has therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the product Kσ and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers.展开更多
We study local linear non-axisymmetric perturbations in fully stratified 3D astrophysical disks. Radial stratification is set to be described by power law, while vertical stratification is set to be exponential. We an...We study local linear non-axisymmetric perturbations in fully stratified 3D astrophysical disks. Radial stratification is set to be described by power law, while vertical stratification is set to be exponential. We analyze the linear perturbations in local shearing sheet frame and derive WKB dispersion equation. We show that stratification laws of the disk matter define not only the thermal stability of the disk, but also the efficiency of the potential vorticity production by rotationg convective turbulence in astrophysical disks. Taken developed convective turbulence we assume nonlinear tendencies set by linear spectrum and show that vortices are unlikely to be generated in rigid rotation flows. In contrast, differential rotation yields much higher vortex production rate that depends on the disk thickness, distance from the central object and the spectral characteristics of the developed thermal turbulence. It seems that measurements of the temperature and density distribution in accretion disks may indicate the efficiency of the turbulence development and largely define the luminosity characteristic of accreting flows.展开更多
Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization.Subsurface geoelectric parameters such as resistivity and thi...Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization.Subsurface geoelectric parameters such as resistivity and thickness obtained from geophysical method(Vertical Electrical Sounding VES)was used to determine aquifers vulnerability,longitudinal resistance(ρL)and transverse unit resistance(Rt).Thirty four water samples were collected from groundwater sources for physicochemical analysis.Estimated results from longitudinal conductance(S),(Rt)and(ρL)showed that the values ranges from 0.03 to 2.5mhos,103.64 to 1964417.8Ω/m^(2) and 215.41 to 65731.68Ω-m respectively.Result from S suggested that 50%of groundwater is considered to be vulnerable to contamination from the earth surface,while the remaining 50%is considered to be slightly vulnerable to surface contamination.Further findings obtained from hydrogeochemical analysis such as Gibb’s and Chadba plots revealed that groundwater is highly influenced by rock water interaction,groundwater is classified to be Na^(+)+HCO_(3)^(-),Ca^(2+)+Mg^(2+)+HCO_(3)^(-),Na^(+)+Cl^(-)and Ca^(2+)+Mg^(2+)+Cl^(-)water type.Deduction from Soltan classification suggested that groundwater is classified to be of Na^(+)+HCO_(3)^(-) and Na^(+)-SO_(4)^(2-) water type.Results obtained from Ec and pH suggested that the values were below WHO permissible limit,while result obtained from TDS showed that at some sampling points TDS values were above WHO limit.Based on pH value obtained groundwater within the study area fell within slightly basic to acidic.展开更多
The thermal conductivity and specific heat capacity of undoped and Al-doped （1–10 at.%） ZnO nanoparticles prepared using the solvent thermal method are determined by measuring both thermal diffusivity and thermal e...The thermal conductivity and specific heat capacity of undoped and Al-doped （1–10 at.%） ZnO nanoparticles prepared using the solvent thermal method are determined by measuring both thermal diffusivity and thermal effusivity of a pressed powder compact of the prepared nanoparticles by using the laser-induced photoacoustic technique. The impact of Al doping versus the microstructure of the samples on such thermal parameters has been investigated. The results reveal an obvious enhancement in the specific heat capacity when decreasing the particle size, while the effect of Al doping on the specific heat capacity is minor. The measured thermal conductivities are about one order of magnitude smaller than that of the bulk ZnO due to several nested reducing heat transfer mechanisms. The results also show that Al doping significantly influences the thermal resistance. Using a simple thermal impedance model, the added thermal resistance due to Al dopant has been estimated.展开更多
The field of environmental sciences is abundant with various interfaces and is the right place for the application of new fundamental approaches leading towards a better understanding of environmental phenomena. Follo...The field of environmental sciences is abundant with various interfaces and is the right place for the application of new fundamental approaches leading towards a better understanding of environmental phenomena. Following the definition of environmental interface by Mihailovic and Bala? [1], such interface can be, for example, placed between: human or animal bodies and surrounding air, aquatic species and water and air around them, and natural or artificially built surfaces (vegetation, ice, snow, barren soil, water, urban communities) and the atmosphere, cells and surrounding environment, etc. Complex environmental interface systems are (i) open and hierarchically organised (ii) interactions between their constituent parts are nonlinear, and (iii) their interaction with the surrounding environment is noisy. These systems are therefore very sensitive to initial conditions, deterministic external perturbations and random fluctuations always present in nature. The study of noisy non-equilibrium processes is fundamental for modelling the dynamics of environmental interface regarded as biophysical complex system and for understanding the mechanisms of spatio-temporal pattern formation in contemporary environmental sciences. In this paper we will investigate an aspect of dynamics of energy flow based on the energy balance equation. The energy exchange between interacting environmen- tal interfaces regarded as biophysical complex systems can be represented by coupled maps. Therefore, we will numerically investigate coupled maps representing that exchange. In ana- lysis of behaviour of these maps we applied Lyapunov exponent and cross sample entropy.展开更多
The astrophysical S-factor forα-^(3)H radiative capture is calculated at astrophysical energies.We construct conserved two-and three-body electromagnetic currents,using minimal substitution in the explicit momentum d...The astrophysical S-factor forα-^(3)H radiative capture is calculated at astrophysical energies.We construct conserved two-and three-body electromagnetic currents,using minimal substitution in the explicit momentum dependence of the two-and three-nucleon interactions.The realistic Argonne v_(18) two-nucleon and Urbana IX or Tucson–Melbourne three-nucleon interactions are considered for calculation.By extrapolation of results for the astrophysical S-factor at zero energy,the energy in the order of 1 keV and less is found to be S(0)=0.107(0.112)keV·b,with(without)three-body interactions in satisfactory agreement with other theoretical results and experimental data.展开更多
This article aims to localise aquifer and to estimate hydraulic parameters such as transmissivity and tranverse resistance in the Memve Ele dam site (26.35 km2) in South-Cameroon region, using audiomagnetotelluric (AM...This article aims to localise aquifer and to estimate hydraulic parameters such as transmissivity and tranverse resistance in the Memve Ele dam site (26.35 km2) in South-Cameroon region, using audiomagnetotelluric (AMT) method. For this purpose, resistivity data are collected at twenty-two measurement stations distributed along two perpendicular profiles in the study area. The sounding curves of phase and impedance are modelled and interpreted. The geological models and geoelectrical sections are also provided. The transverse resistivity and transmissivity field maps are plotted. The audiomagnetotellurics insights have been compared with boreholes. All these results allow us to localise the area which may be suitable to set up monitoring wells.展开更多
Electrical and geological methods are used to conduct petrophysical study in Douala-Cameroon sedimentary basin along Yaounde-Douala National road No. 3. Studies in this region are made of three outcrops, namely: Misso...Electrical and geological methods are used to conduct petrophysical study in Douala-Cameroon sedimentary basin along Yaounde-Douala National road No. 3. Studies in this region are made of three outcrops, namely: Missolè II located on the sedimentary basin of Douala, Edea and Sikoum which are outcrops of basement rocks that form the eastern boundary of the sedimentary basin of Douala. This study reveals that the rocks of the sedimentary basin of Douala are mainly composed of sandstone and clay. Both basement rocks of Edea and Sikoum are subjected to the same phases of deformation. These phases of deformation give the quartzite a particular structure that greatly influences the resistivity and density of these rocks and give it a planar anisotropy.展开更多
We have found that fractional principal quantum numbers are permitted in hydrogen atom which yield the conditions for neutron and white dwarf stars evolution. The number densities of neutron and white dwarf stars reve...We have found that fractional principal quantum numbers are permitted in hydrogen atom which yield the conditions for neutron and white dwarf stars evolution. The number densities of neutron and white dwarf stars reveal that these systems have the maximal conductivity of 1.37×1010Ω-1m-1. They are giant perfect conductors at very high temperature and magnetic field.展开更多
Aim: The purpose of this study was to make a comparison between measured and calculated physical wedge dose distributions using the superposition algorithm. Settings and Design: The accurate determination of absorbed ...Aim: The purpose of this study was to make a comparison between measured and calculated physical wedge dose distributions using the superposition algorithm. Settings and Design: The accurate determination of absorbed dose is important radiotherapy because of the relatively steep sigmoidal dose response curves for both tumor control and normal-tissue damage. Materials and Methods: High-energy photons (6 and 10 MV) from Artiste Treatment System Linear Accelerator Machine, available at Alexandria Ayadi Al-Mostakbal Oncology Center, were used. Results and Discussion: The results showed that the difference between measured and calculated wedged isodose curves depends on field size, beam energy, and the angle of the used wedge. Conclusion: The results showed that the presence of a wedge alters the primary and scattered components generated by a linear accelerator and causes beam hardening in 6 and 10 MV. The beam hardening increased as the wedge angle increased.展开更多
文摘Based on the density functional theory,the double half-Heusler alloys LuXCo_(2)Bi_(2)(X=V,Nb,and Ta)were studied to predict their structural,thermodynamic,thermoelectric,and optical characteristics.All the considered alloys are thermodynamically stable and have semiconductor behavior with indirect band gaps of 0.62,0.75,and 0.8 eV for LuVCo_(2)Bi_(2),LuNbCo_(2)Bi_(2),and LuTaCu_(2)Bi_(2),respectively.The investigated compounds exhibit semiconducting behavior with energy gaps below 0.8 eV.The impact of heat and pressure on thermodynamic coefficients was evaluated,and the influence of charge carriers on the temperature-dependent properties was studied using the semi-classical Boltzmann model.The studied compounds were characterized by their low lattice thermal conductivity at room temperature and low thermal expansion coefficient.These alloys exhibit substantial absorption coefficients in the ultraviolet(UV)light region,high optical conductivity,and high reflectivity in the visible light region,making them highly appealing materials for applications in the energy and electronics sectors.
基金funded by the Ministry of Higher Education through Universiti Putra Malaysia(UPM)under Grant FRGS/1/2023/STG07/UPM/02/4.
文摘Detecting geomagnetic anomalies preceding earthquakes is a challenging yet promising area of research that has gained increasing attention in recent years.This study introduces a novel reconstruction-based modeling approach enhanced by negative learning,employing a Bidirectional Long Short-Term Memory(BiLSTM)network explicitly trained to accurately reconstruct non-seismic geomagnetic signals while intentionally amplifying reconstruction errors for seismic signals.By penalizing the model for accurately reconstructing seismic anomalies,the negative learning approach effectively magnifies the differences between normal and anomalous data.This strategic differentiation enhances the sensitivity of the BiLSTM network,enabling improved detection of subtle geomagnetic anomalies that may serve as earthquake precursors.Experimental validation clearly demonstrated statistically significant higher reconstruction errors for seismic signals compared to non-seismic signals,confirmed through the Mann-Whitney U test with a p-value of 0.0035 for Root Mean Square Error(RMSE).These results provide compelling evidence of the enhanced anomaly detection capability achieved through negative learning.Unlike traditional classification-based methods,negative learning explicitly encourages sensitivity to subtle precursor signals embedded within complex geomagnetic data,establishing a robust basis for further development of reliable earthquake prediction methods.
文摘This study presents a numerical investigation of the transient relaxation dynamics of a near-critical CO_(2)droplet immersed in a warmer supercritical environment composed of the same fluid.Three thermodynamic regimes were analysed:quasi-critical(T_(r)=1.01,P_(r)=1.01),transitional(T_(r)=2.01,P_(r)=1.01),and deep supercritical(T_(r)=5.01,P_(r)=3.01).Theevolution of density,temperature,and velocity fieldswas examined to characterize the internal structure and stability of the interfacial transition layer.The evolution of density,temperature,and velocity fields highlights the competition between thermal diffusion,compressibility,andmass confinement in shaping the stability of the interfacial transition layer.Near the critical point,strong gradients and flux discontinuities emerge,consistent with known instabilities,whereas higher reduced conditions promote homogenization and stabilized transport.In the deep supercritical regime,smooth and nearly uniform fields indicate robust thermal stability.The model is validated against prior studies on droplet evaporation under supercritical and trans-critical conditions.Beyond theoretical insights,the results underline practical implications for advanced propulsion,heat transfer,and evaporation systems as well as for safe CO_(2)supercritical storage and extraction processes in energy,aerospace,pharmaceutical,and materials industries.
基金the financial support from the Key Project of Shaanxi Provincial Natural Science Foundation-Key Project of Laboratory(2025SYS-SYSZD-117)the Natural Science Basic Research Program of Shaanxi(2025JCYBQN-125)+8 种基金Young Talent Fund of Xi'an Association for Science and Technology(0959202513002)the Key Industrial Chain Technology Research Program of Xi'an(24ZDCYJSGG0048)the Key Research and Development Program of Xianyang(L2023-ZDYF-SF-077)Postdoctoral Fellowship Program of CPSF(GZC20241442)Shaanxi Postdoctoral Science Foundation(2024BSHSDZZ070)Research Funds for the Interdisciplinary Projects,CHU(300104240913)the Fundamental Research Funds for the Central Universities,CHU(300102385739,300102384201,300102384103)the Scientific Innovation Practice Project of Postgraduate of Chang'an University(300103725063)the financial support from the Australian Research Council。
文摘Lithium-ion batteries(LIBs),while dominant in energy storage due to high energy density and cycling stability,suffer from severe capacity decay,rate capability degradation,and lithium dendrite formation under low-temperature(LT)operation.Therefore,a more comprehensive and systematic understanding of LIB behavior at LT is urgently required.This review article comprehensively reviews recent advancements in electrolyte engineering strategies aimed at improving the low-temperature operational capabilities of LIBs.The study methodically examines critical performance-limiting mechanisms through fundamental analysis of four primary challenges:insufficient ionic conductivity under cryogenic conditions,kinetically hindered charge transfer processes,Li+transport limitations across the solidelectrolyte interphase(SEI),and uncontrolled lithium dendrite growth.The work elaborates on innovative optimization approaches encompassing lithium salt molecular design with tailored dissociation characteristics,solvent matrix optimization through dielectric constant and viscosity regulation,interfacial engineering additives for constructing low-impedance SEI layers,and gel-polymer composite electrolyte systems.Notably,particular emphasis is placed on emerging machine learning-guided electrolyte formulation strategies that enable high-throughput virtual screening of constituent combinations and prediction of structure-property relationships.These artificial intelligence-assisted rational design frameworks demonstrate significant potential for accelerating the development of next-generation LT electrolytes by establishing quantitative composition-performance correlations through advanced data-driven methodologies.
基金supported by the National Natural Science Foundation of China (No.22409038,52473221)Zhejiang Province Postdoctoral Science Foundation (No.ZJ2024021)+2 种基金Hubei Provincial Natural Science Foundation of China (Nos.2024DJC032,2025AFB889)Key Project of Science and Technology Research of Hubei Provincial Department of Education (Nos.D20232701,D20232702)the research grant funded by the Research,Development,and Innovation Authority (RDIA)-Kingdom of Saudi Arabia (No.12615-iu-2023-IU-R-2-1-EI-)。
文摘Hydrogen peroxide(H_(2)O_(2)) has been recognized as a green and nonpolluting multifunctional oxidant with extensive applications in environmental protection,metal etching,textile printing and dyeing,chemical synthesis and food processing.However,over 90 % of industrial H_(2)O_(2) is currently produced through the multi-step anthraquinone oxidation process,which suffers from a process with some drawbacks such as complex,high-energy consumption,and toxic byproducts emissions.Compared to the traditional anthraquinone method,artificial photosynthesis of H_(2)O_(2) using semiconductor photocatalysts has emerged as a sustainable alternative due to its use of water and O_(2) as the clean reactants and sole energy as the driving force.In recent years,metal-free photocatalysts mainly including covalent organic frameworks(COFs),covalent triazine frameworks(CTFs) and carbon nitrile(g-C_(3)N_(4)) have garnered significant interest due to their superior thermal and chemical stability,diverse synthesis methods,tunable functionality,light weight nature and non-toxicity.These materials also exhibit adjustable band structure and unique photoelectric properties.Sustainable efforts have been made to advance metal-free photocatalysts for artificial photosynthesis of H_(2)O_(2),however,a comprehensive summary of current research status on metalfree-based photocatalytic overall H_(2)O_(2) production remain scarce.This review outlines recent process in overall H_(2)O_(2) photosynthesis based on metal-free photocatalysts.First,we introduced the fundamental concepts of photocatalytic overall H_(2)O_(2) production.Then,we analyze representative studies on photocatalytic overall H_(2)O_(2) synthesis using metal-free materials.Finally,we discuss the challenges and future perspectives in this field to guide the design and synthesis of metal-free systems for H_(2)O_(2) generation.
基金the Deanship of Research and Graduate Studies at King Khalid University,Saudi Arabia,for funding this study through the Large Groups Project(Grant No.RGP2/2/47)the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through project number NBU-FFR-2025-1902-02。
文摘Cu_(x)Ta_(2-x)O_(5) compositions were investigated for advanced thermoelectric and optical applications,using both simulations and experimental approaches.Density functional theory calculations were performed before the experimental observations to predict the trends of various parameters.Crystal structure analysis confirmed the presence of the orthorhombic Ta_(2)O_(5) phase in all the compositions.The composition and morphology demonstrated impurity-free contents with uniform and crack-free surfaces.Thermoelectric analysis depicted a decrease in Seebeck coefficient from 3.66??V·K^(-1)to 1.91??V·K^(-1)and an increase in the value of specific heat from 0.73 J·K^(-1)·kg^(-1)to 11.6 J·K^(-1)·kg^(-1)upon Cu incorporation in structure.The bandgap was found to reduce from 2.61 to 1.38 e V with Cu-induced electronic states.The real epsilon and static refractive index increased from 3.75 to 4.57 and from 1.93 to 2.11,respectively,with increment in Cu content.The enhanced parameters,focusing on the thermoelectric and optical responses,make these compositions potential candidates for advanced optoelectronic applications.
文摘The paper concludes that the energy given by Einstein’s famous formula E = mc2 consists of two parts. The first part is the positive energy of the quantum particle modeled by the topology of the zero set. The second part is the absolute value of the negative energy of the quantum Schr?dinger wave modeled by the topology of the empty set. We reason that the latter is nothing else but the so called missing dark energy of the universe which accounts for 94.45% of the total energy, in full agreement with the WMAP and Supernova cosmic measurement which was awarded the 2011 Nobel Prize in Physics. The dark energy of the quantum wave cannot be detected in the normal way because measurement collapses the quantum wave.
基金Project supported by the Ministry of Higher Education Malaysia and Universiti Teknologi Malaysia through Research University Grant Scheme(17H79,18H68,03G72)International Doctoral Fellowship(IDF)and UTM Zamalah Scholarship
文摘Intense visible emissions from dysprosium(Dy3+) ions doped glasses became prospective for diverse technological applications. In this paper, physical, optical and structural properties of magnesium borate glasses doped with varied concentrations of DyOwere examined. Such glasses were synthesised by melt quenching method and characterized at room temperature using several analytical techniques.Luminescence and absorption spectra(in the visible region) of as-quenched samples were used to evaluate the physical and optical properties. XRD pattern confims the amorphous state of as-quenched samples. The Fourier transform infrared(FTIR) spectra of glasses reveal various bonding vibrations assigned to different functional groups. UV-vis-NIR spectra disclose eight absorption bands accompanied by a band for hypersensitive transition positioned at 1260 nm(~6 H→~6 F). The values of direct and indirect optical energy band gap of the studied glasses are decreased with the increase of Dyion contents. The photoluminescence spectra of all glasses under the excitation of 380 nm display two prominent emission bands centred at 497 nm(~4 F→~6 H, blue) and 587 nm(~4 F→~6 H, green).The achieved intense luminescence from the proposed glass composition may be beneficial for solidstate laser applications.
基金supported by Erciyes University Scientific Research Project Unit (No.FBA-10-3376)
文摘Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates （5.32-250.0μm/s） at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus.The values of eutectic spacing were measured from transverse sections of the samples.The dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53,respectively.The results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the literature.Microhardness of directionally solidified samples was also measured by using a microhardness test device.The dependency of the microhardness on growth rate is found as Hv=115.64V0.13.Afterwards,the electrical resistivity （r） of the casting alloy changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300-630 K.The enthalpy of fusion （ΔH） and specific heat （Cp） for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/（g·K）,respectively by means of differential scanning calorimetry （DSC） from heating trace during the transformation from liquid to solid.
文摘Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. The transmissivity of the uncon?ned aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and transverse resistance. The relationship established has therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the product Kσ and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers.
文摘We study local linear non-axisymmetric perturbations in fully stratified 3D astrophysical disks. Radial stratification is set to be described by power law, while vertical stratification is set to be exponential. We analyze the linear perturbations in local shearing sheet frame and derive WKB dispersion equation. We show that stratification laws of the disk matter define not only the thermal stability of the disk, but also the efficiency of the potential vorticity production by rotationg convective turbulence in astrophysical disks. Taken developed convective turbulence we assume nonlinear tendencies set by linear spectrum and show that vortices are unlikely to be generated in rigid rotation flows. In contrast, differential rotation yields much higher vortex production rate that depends on the disk thickness, distance from the central object and the spectral characteristics of the developed thermal turbulence. It seems that measurements of the temperature and density distribution in accretion disks may indicate the efficiency of the turbulence development and largely define the luminosity characteristic of accreting flows.
文摘Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization.Subsurface geoelectric parameters such as resistivity and thickness obtained from geophysical method(Vertical Electrical Sounding VES)was used to determine aquifers vulnerability,longitudinal resistance(ρL)and transverse unit resistance(Rt).Thirty four water samples were collected from groundwater sources for physicochemical analysis.Estimated results from longitudinal conductance(S),(Rt)and(ρL)showed that the values ranges from 0.03 to 2.5mhos,103.64 to 1964417.8Ω/m^(2) and 215.41 to 65731.68Ω-m respectively.Result from S suggested that 50%of groundwater is considered to be vulnerable to contamination from the earth surface,while the remaining 50%is considered to be slightly vulnerable to surface contamination.Further findings obtained from hydrogeochemical analysis such as Gibb’s and Chadba plots revealed that groundwater is highly influenced by rock water interaction,groundwater is classified to be Na^(+)+HCO_(3)^(-),Ca^(2+)+Mg^(2+)+HCO_(3)^(-),Na^(+)+Cl^(-)and Ca^(2+)+Mg^(2+)+Cl^(-)water type.Deduction from Soltan classification suggested that groundwater is classified to be of Na^(+)+HCO_(3)^(-) and Na^(+)-SO_(4)^(2-) water type.Results obtained from Ec and pH suggested that the values were below WHO permissible limit,while result obtained from TDS showed that at some sampling points TDS values were above WHO limit.Based on pH value obtained groundwater within the study area fell within slightly basic to acidic.
基金the Deanship of Scientific Research,King Faisal University,Saudi Arabia(Grant No.130154)
文摘The thermal conductivity and specific heat capacity of undoped and Al-doped （1–10 at.%） ZnO nanoparticles prepared using the solvent thermal method are determined by measuring both thermal diffusivity and thermal effusivity of a pressed powder compact of the prepared nanoparticles by using the laser-induced photoacoustic technique. The impact of Al doping versus the microstructure of the samples on such thermal parameters has been investigated. The results reveal an obvious enhancement in the specific heat capacity when decreasing the particle size, while the effect of Al doping on the specific heat capacity is minor. The measured thermal conductivities are about one order of magnitude smaller than that of the bulk ZnO due to several nested reducing heat transfer mechanisms. The results also show that Al doping significantly influences the thermal resistance. Using a simple thermal impedance model, the added thermal resistance due to Al dopant has been estimated.
基金funded by the Serbian Ministry of Science and Technology under the project No.III 43007“Research of climate changes and their impact on environment.Monitoring of the impact,adaptation and moderation”for 2011-2014.
文摘The field of environmental sciences is abundant with various interfaces and is the right place for the application of new fundamental approaches leading towards a better understanding of environmental phenomena. Following the definition of environmental interface by Mihailovic and Bala? [1], such interface can be, for example, placed between: human or animal bodies and surrounding air, aquatic species and water and air around them, and natural or artificially built surfaces (vegetation, ice, snow, barren soil, water, urban communities) and the atmosphere, cells and surrounding environment, etc. Complex environmental interface systems are (i) open and hierarchically organised (ii) interactions between their constituent parts are nonlinear, and (iii) their interaction with the surrounding environment is noisy. These systems are therefore very sensitive to initial conditions, deterministic external perturbations and random fluctuations always present in nature. The study of noisy non-equilibrium processes is fundamental for modelling the dynamics of environmental interface regarded as biophysical complex system and for understanding the mechanisms of spatio-temporal pattern formation in contemporary environmental sciences. In this paper we will investigate an aspect of dynamics of energy flow based on the energy balance equation. The energy exchange between interacting environmen- tal interfaces regarded as biophysical complex systems can be represented by coupled maps. Therefore, we will numerically investigate coupled maps representing that exchange. In ana- lysis of behaviour of these maps we applied Lyapunov exponent and cross sample entropy.
文摘The astrophysical S-factor forα-^(3)H radiative capture is calculated at astrophysical energies.We construct conserved two-and three-body electromagnetic currents,using minimal substitution in the explicit momentum dependence of the two-and three-nucleon interactions.The realistic Argonne v_(18) two-nucleon and Urbana IX or Tucson–Melbourne three-nucleon interactions are considered for calculation.By extrapolation of results for the astrophysical S-factor at zero energy,the energy in the order of 1 keV and less is found to be S(0)=0.107(0.112)keV·b,with(without)three-body interactions in satisfactory agreement with other theoretical results and experimental data.
文摘This article aims to localise aquifer and to estimate hydraulic parameters such as transmissivity and tranverse resistance in the Memve Ele dam site (26.35 km2) in South-Cameroon region, using audiomagnetotelluric (AMT) method. For this purpose, resistivity data are collected at twenty-two measurement stations distributed along two perpendicular profiles in the study area. The sounding curves of phase and impedance are modelled and interpreted. The geological models and geoelectrical sections are also provided. The transverse resistivity and transmissivity field maps are plotted. The audiomagnetotellurics insights have been compared with boreholes. All these results allow us to localise the area which may be suitable to set up monitoring wells.
文摘Electrical and geological methods are used to conduct petrophysical study in Douala-Cameroon sedimentary basin along Yaounde-Douala National road No. 3. Studies in this region are made of three outcrops, namely: Missolè II located on the sedimentary basin of Douala, Edea and Sikoum which are outcrops of basement rocks that form the eastern boundary of the sedimentary basin of Douala. This study reveals that the rocks of the sedimentary basin of Douala are mainly composed of sandstone and clay. Both basement rocks of Edea and Sikoum are subjected to the same phases of deformation. These phases of deformation give the quartzite a particular structure that greatly influences the resistivity and density of these rocks and give it a planar anisotropy.
文摘We have found that fractional principal quantum numbers are permitted in hydrogen atom which yield the conditions for neutron and white dwarf stars evolution. The number densities of neutron and white dwarf stars reveal that these systems have the maximal conductivity of 1.37×1010Ω-1m-1. They are giant perfect conductors at very high temperature and magnetic field.
文摘Aim: The purpose of this study was to make a comparison between measured and calculated physical wedge dose distributions using the superposition algorithm. Settings and Design: The accurate determination of absorbed dose is important radiotherapy because of the relatively steep sigmoidal dose response curves for both tumor control and normal-tissue damage. Materials and Methods: High-energy photons (6 and 10 MV) from Artiste Treatment System Linear Accelerator Machine, available at Alexandria Ayadi Al-Mostakbal Oncology Center, were used. Results and Discussion: The results showed that the difference between measured and calculated wedged isodose curves depends on field size, beam energy, and the angle of the used wedge. Conclusion: The results showed that the presence of a wedge alters the primary and scattered components generated by a linear accelerator and causes beam hardening in 6 and 10 MV. The beam hardening increased as the wedge angle increased.
