This study tested the electrical conductivity and pressure sensitivity of lime⁃improved silty sand reinforced with Carbon Fiber Powder(CFP)as the conductive medium.The influence of CFP dosage,moisture content and curi...This study tested the electrical conductivity and pressure sensitivity of lime⁃improved silty sand reinforced with Carbon Fiber Powder(CFP)as the conductive medium.The influence of CFP dosage,moisture content and curing duration on the unconfined compressive strength,initial resistivity and pressure sensitivity of the improved soil was systematically analysed.The results showed that the unconfined compressive strength varied non⁃monotonically with increasing CFP dosage,reaching a peak at a dosage of 1.6%.Furthermore,the initial resistivity showed slight variations under different moisture conditions but eventually converged towards the conductive percolation threshold at a dosage of 2.4%.It is worth noting that CFP reinforced lime⁃improved silty sand(CRLS)exhibit a clear dynamic synchronization of strain with stress and resistivity rate of variation.The pressure sensitivity was optimized with CFP dosages ranging from 1.6%to 2.0%.Both insufficient and excessive dosages had a negative impact on pressure sensitivity.It is important to consider the weakening effect of high moisture content on the pressure sensitivity of the specimens in practical applications.展开更多
This study,based on Artificial Neural Network(ANN)technology,develops a quantitative prediction model for the unit water flow rate of the Quaternary strata in the Shijiazhuang-Hebei Plain area.The study area extends f...This study,based on Artificial Neural Network(ANN)technology,develops a quantitative prediction model for the unit water flow rate of the Quaternary strata in the Shijiazhuang-Hebei Plain area.The study area extends from the piedmont region of Shijiazhuang,at the eastern foothills of the Taihang Mountains,to the hinterland area of Hengshui within the plain in Hebei Province section of the North China Plain.The hydrological and exploration boreholes selected for modeling are primarily located in the south-eastern part of Shijiazhuang urban area—the southern region of Xinji County—north of Hengshui City near the Shenzhou County area.By employing the Induced Polarization method(IP)and Vertical Electrical Sounding(VES),apparent resistivity(ρS),apparent polarization rate(ηS),half-decay time(Th),and decay degree(D)were obtained as initial input parameters.These were combined with the measured water flow rates from borehole pumping tests to build the training sample set.To address the prevalent issue of high-salinity interference in the study area,multiple regression analysis revealed that when the inverted resistiv-ity(ρ)is less than 5Ω·m and the inverted polarization rate(η)is greater than 8%,the contribution of groundwater salinity to the resistivity parameter reaches 42%±6%.Based on this,a comprehensive parame-ter T"=ρ*H/ρ'was established,whereρis the aquifer resistivity,ρ'is the aquitard resistivity,and H is the aquifer thickness.The resistivity ratio effectively eliminates the coupling effect between electrical parame-ters and salinity.The input neurons of the improved model were adjusted to a four-parameter system consisting of decay time(Th),decay degree(D),deviation degree(σ),and the comprehensive parameter(T").Experiments showed that the prediction error of the model on the validation set was reduced from the original model's 5%-10%to 0.9%-5%.The introduction of the T"parameter reduced the prediction error in high salinity areas(Cl->500 mg/L)to within 7%.The study confirms that the composite parameter T"based on geophysical inversion parameters can effectively characterize the coupling features of aquifer thickness and water quality.Even with a small sample size,through algorithm optimization,data augmentation,and model structural improvements,it is entirely possible to effectively enhance prediction accuracy and gener-alization ability,providing a new parameterization method for the quantitative evaluation of Quaternary pore water in plain areas.展开更多
Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(...Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(in order of increasing Ag content:A10,A20,A30,and A40)were surface-modified with stearic acid,to suppress the Ag shell dewetting and improve sinterability.The surface-modified particles were mixed with a polyol-based solvent to fabricate a resin-free paste.Subsequently,the pastes were screen-printed onto a slide glass and sintered at 250°C in a nitrogen atmosphere for 1-10 min to form an electrode.The electrical resistivity of the sintered film as a function of sintering time was measured using a four-point probe.All the four surface-modified Cu@Ag particles with different Ag contents exhibited decreased electrical resistivity.Particularly,the largest difference in values after and before the surface modification was observed for A40 with the highest Ag content;the electrical resistivities of the initial and surface-modified particles were 1.51×10^(-4) and 6.67×10^(-5)Ω·cm,respectively,after sintering for 10 min.The findings of this study confirmed that the surface modification using stearic acid effectively suppressed the dewetting of the Ag shell and improved the sinterability of the submicron Cu@Ag particles.展开更多
This paper describes the synthesis and characterization of Nb_(2)TiW and Nb_(2)TiMo medium-entropy alloys(MEAs).The Nb_(2)TiW and Nb_(2)TiMo MEAs were successfully synthesized using the arc-melting method.Their struct...This paper describes the synthesis and characterization of Nb_(2)TiW and Nb_(2)TiMo medium-entropy alloys(MEAs).The Nb_(2)TiW and Nb_(2)TiMo MEAs were successfully synthesized using the arc-melting method.Their structures and superconducting properties were investigated through detailed characterization using X-ray diffraction(XRD),resistivity,magnetization,and specific heat measurements.The XRD results confirmed that the obtained Nb_(2)TiW and Nb_(2)TiMo compounds have the same body-centered cubic(BCC)structure and crystallize in the Imˉ3m space group(number 229).Experimental results showed that the superconducting transition temperatures(Tcs)of Nb_(2)TiW and Nb_(2)TiMo are approximately 4.86 and 3.22 K,respectively.The upper and lower critical fields of Nb_(2)TiW are 3.52(2)T and 53.36(2)Oe,respectively,and those of Nb_(2)TiMo are 2.11(2)T and 68.23(3)Oe,respectively.First-principles calculations revealed that the d electrons of Nb,Ti,andMo orW are the dominant contributors to the density of states near the Fermi level.Specific heat measurement results indicated that Nb_(2)TiW and Nb_(2)TMo exhibit BCS full-gap s-wave superconductivity.展开更多
Evaluating the stabilized lead(Pb)-contaminated soils through sampling and laboratory testing involves costly and time-consuming processes.Therefore,this study employed a low-cost and non-destructive resistivity tool ...Evaluating the stabilized lead(Pb)-contaminated soils through sampling and laboratory testing involves costly and time-consuming processes.Therefore,this study employed a low-cost and non-destructive resistivity tool to evaluate the Pb-contaminated soils stabilized by electrolytic manganese residue(EMR)-based geopolymer(EG-OPC)from the strength and environmental benefits perspective.First,unconfined compressive strength(UCS)and leaching tests were conducted to study the stabilization effectiveness of EG-OPC.Results indicated that the UCS values of soil(5000 mg/kg of pollutants)stabilized by 20%EG-OPC were 4.87 MPa and 8.13 MPa after 7 d and 60 d of curing,respectively.After 60 d of curing,the Pb concentration in the leachate reached 44 mg/L,far lower than the control group(321 mg/L).Second,soil,pore water,and leachate resistivity(ERS,ERW,and ERL)were measured to establish fitting relationships with strength parameters and pollution risk.The good fitting results(e.g.ERS/ERW versus UCS/secant modulus(E50):correlation coefficient R2 z 0.9,ERS/ERW versus Pb contents:R2 z 0.9,and ERL versus Pb2þconcentration:R2¼0.92)and well used Archie's law(ERS versus ERW:R2>0.9)indicate that the resistivity can be used to evaluate the stabilization effectiveness.Furthermore,the microscopic results revealed two behaviors,demonstrating the reliability of resistivity:(1)with the hydration process,resistivity increases due to a denser structure and lower amounts of free water and Pb ions,and(2)the addition of Pb reduces resistivity due to its inhibition or even destructive effects on cementation and formation of hydration products.展开更多
This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Me...This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.展开更多
Natural gas hydrates are widely distributed in marine and permafrost environments.As a novel energy resource,accurately describing reservoir characteristics and assessing energy potential is crucial for its commercial...Natural gas hydrates are widely distributed in marine and permafrost environments.As a novel energy resource,accurately describing reservoir characteristics and assessing energy potential is crucial for its commercial development.Resistivity logging serves as a valuable approach for achieving these goals.Nevertheless,due to inadequate comprehension of the electrical conductivity mechanism in hydrate-bearing sediments,existing data processing models still encounter certain challenges.This study conducts both core-scale and pore-scale simulation experiments to examine the relationship between resistivity variations and the distribution of gas hydrate porosity.The results indicate that the characteristics of resistivity variation is associated with the gas hydrate formation process,and the gas hydrate saturation index,denoted as‘n',varies between 0 and 3 depending on different gas hydrate distribution patterns.As the saturation increases,gas hydrate distribution in pore spaces transitions from floating to contacting and cementing patterns.It is proposed that the aqueous pore tortuosity can be utilized to correct the saturation index‘n'in Archie's equation.Based on the analysis of experimental data,a correction method for Archie's equation is suggested,and its effectiveness in controlling relative error has been validated.展开更多
To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing mate...To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing materials is proposed.Firstly,the sound absorption coefficients of a fibrous sound-absorbing material are measured at two different frequencies using the impedance tube method.Secondly,utilizing the empirical formulas for the wavenumber and acoustic impedance in the fibrous material,the flow resistivity and porosity of the sound-absorbing materials are calculated using the MATLAB cycle program.Thirdly,based on the values obtained through reverse calculations,the sound absorption coefficient,the real and the imaginary parts of the acoustic impedance of the sound-absorbing material at different frequencies are theoretically computed.Finally,the accuracy of these theoretical calculations is verified through experiments.The experimental results indicate that the calculated values are basically consistent with the measured values,demonstrating the feasibility and reliability of this method.展开更多
During underground excavation,the surrounding rock mass is subjected to complex cyclic stress,significantly impacting its long-term stability,especially under varying water content conditions where this effect is ampl...During underground excavation,the surrounding rock mass is subjected to complex cyclic stress,significantly impacting its long-term stability,especially under varying water content conditions where this effect is amplified.However,research on the mechanical response mechanisms of surrounding rock mass under such conditions remains inadequate.This study utilized acoustic emission(AE)and resistivity testing to monitor rock fracture changes,revealing the rock’s damage state and characterizing the damage evolution process during uniaxial cyclic loading and unloading.First,a damage variable equation was established based on AE and resistivity parameters,leading to the derivation of a corresponding damage constitutive equation.Uniaxial cyclic loading and unloading tests were then conducted on sandstone samples with varying water contents,continuously monitoring AE signals and resistivity,along with computed tomography scans before and after failure.The predictions from the damage constitutive equation were compared with experimental results.This comparison shows that the proposed damage variable equation effectively characterizes the damage evolution of sandstone during loading and unloading,and that the constitutive equation closely fits the experimental data.This study provides a theoretical basis for monitoring and assessing the responses of surrounding rock mass during underground excavation.展开更多
Evaluation of backfilling effectiveness plays a crucial role in the geological environment management and restoration of abandoned open-pit quarries,providing a scientific basis for subsequent greening efforts.Backfil...Evaluation of backfilling effectiveness plays a crucial role in the geological environment management and restoration of abandoned open-pit quarries,providing a scientific basis for subsequent greening efforts.Backfill soil,predominantly composed of silty clay,demonstrates high water retention capacity and elevated moisture content,leading to a pronounced resistivity contrast with the bedrock exposed by quarrying activities.To investigate the distribution of backfill soil subsurface and assess backfilling effectiveness in the study area,this study conducted a comprehensive geophysical investigation utilizing the high-density electrical resistivity tomography(ERT).A total of 19 ERT survey lines were deployed across three distinct areas in Liuyao Village,Huaibei City,Anhui Province,China.The inversion results,derived from both two-dimensional(2D)and three-dimensional(3D),reveal distinct electrical properties of the subsurface materials:the backfill soil layer shows low resistivity features,the fill stone layer exhibits medium to high resistivity,and the bedrock shows the highest resistivity.The 2D inversion results,from the data measured using the Wenner array effectively capture the spatial distribution and structural features of the backfill soil layer.The findings indicate a gradual east-west thinning of the clay layer within the quarry.Furthermore,the northern pit area exhibits a uniform distribution of backfill soil layer,indicative of effective backfilling operations.In contrast,the southern pit area lacks a well-defined clay layer,suggesting suboptimal backfilling effectiveness.展开更多
Taking the Qihe area as an example,this paper compared various geophysical exploration methods in view of the problems of urban construction,deep thermal reservoir burial,and vast overlying low-resistance shield layer...Taking the Qihe area as an example,this paper compared various geophysical exploration methods in view of the problems of urban construction,deep thermal reservoir burial,and vast overlying low-resistance shield layer in deep karst geothermal exploration.A Controlledsource audio magnetotelluric(CSAMT)method was taken to overcome the problems and detect deep stratigraphic structures in the study area.The acquisition parameters of CSAMT were optimized to take into account the exploration depth and signal-to-noise ratio.The distortion of data in the near and transition zone was eliminated by the inversion of equivalent whole-region apparent resistivity,so as to achieve the purpose of deep sounding.Based on the resistivity profile resulting from the proposed CSAMT method,three faults were inferred and one low-resistance anomaly zone in the area was traced.The results of the profile interpretation were verified by drilling.The inferred stratigraphic boundaries and low-resistance anomaly zone were basically in agreement with the drilling results,thereby proving the eff ectiveness of the CSAMT method for deep geothermal exploration in low-resistance coverage areas.This method could provide technical support for deep geothermal exploration in similar areas.展开更多
The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the...The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the high gradient in the cryogenic photoinjector make it possible to improve the performance of new light sources.As an upgrading scheme for the Shanghai Soft X-ray Free-Electron Laser,this study explores a novel photocathode RF gun by introducing the TM_(02)mode into the cathode cell of a 2.6-cell electron gun,which improves the RF performance,particularly in terms of the monopole field.Furthermore,the optimized cathode cell with the TM_(02)mode can reduce the errors resulting from installation and decrease the dark current with alternative cathodes.In this study,the beam dynamics in a photoinjector were optimized using a 500-pC,5-ps beam,and its feasibility was examined.This paper presents the entire RF design process,including the adjustment of the RF structure,coupler design,local field,and multipole mode suppression to provide theoretical guidance for subsequent manufacturing and assembly.展开更多
AlGaN-based LEDs with peak wavelength below 240 nm(far-UVC)pose no significant harm to human health,thus highlighting their broader application potential.While,there is a significant Schottky barrier between the n-ele...AlGaN-based LEDs with peak wavelength below 240 nm(far-UVC)pose no significant harm to human health,thus highlighting their broader application potential.While,there is a significant Schottky barrier between the n-electrode and Alrich n-AlGaN,adversely impeding electron injection and resulting in considerable heat generation.Here,we fabricate V-based electrodes of V/Al/Ti/Au on n-AlGaN with Al content over 80%and investigate the relationship between the metal diffusion and contact properties during the high-temperature annealing process.Experiments reveal that decreasing V thickness in the electrode promotes the diffusion of Al towards the surface of n-AlGaN,which facilitates the formation of VN and thus the increase of local electron concentration,resulting in lower specific contact resistivity.Then,increasing the Al thickness inhibits the diffusion of Au to the n-AlGaN surface,suppressing the rise of Schottky barrier.Experimentally,an optimized n-electrode of V(10 nm)/Al(240 nm)/Ti(40 nm)/Au(50 nm)on n-Al_(0.81)Ga_(0.19)N is obtained,realizing an optimal specific contact resistivity of 7.30×10^(−4)Ω·cm^(2).Based on the optimal n-electrode preparation scheme for Al-rich n-AlGaN,the work voltage of a far-UVC LED with peak wavelength of 233.5 nm is effectively reduced.展开更多
Characterization of vegetation effect on soil response is essential for comprehending site-specific hydrological processes.Traditional research often relies on sensors or remote sensing data to examine the hydrologica...Characterization of vegetation effect on soil response is essential for comprehending site-specific hydrological processes.Traditional research often relies on sensors or remote sensing data to examine the hydrological properties of vegetation zones,yet these methods are limited by either measurement sparsity or spatial inaccuracy.Therefore,this paper is the first to propose a data-driven approach that incorporates high-temporal-resolution electrical resistivity tomography(ERT)to quantify soil hydrological response.Time-lapse ERT is deployed on a vegetated slope site in Foshan,China,during a discontinuous rainfall induced by Typhoon Haikui.A total of 97 ERT measurements were collected with an average time interval of 2.7 hours.The Gaussian Mixture Model(GMM)is applied to quantify the level of response and objectively classify impact zones based on features extracted directly from the ERT data.The resistivity-moisture content correlation is established based on on-site sensor data to characterize infiltration and evapotranspiration across wet-dry conditions.The findings are compared with the Normalized Difference Vegetation Index(NDVI),a common indicator for vegetation quantification,to reveal potential spatial errors in remote sensing data.In addition,this study provides discussions on the potential applications and future directions.This paper showcases significant spatio-temporal advantages over existing studies,providing a more detailed and accurate characterization of superficial soil hydrological response.展开更多
公开(公告)号:US12242011B2 Method for estimating water saturation in gas reservoirs using acoustic log P-wave and S-wave velocites利用声波测井纵波和横波速度估算气藏含水饱和度的方法摘要:The present application relates t...公开(公告)号:US12242011B2 Method for estimating water saturation in gas reservoirs using acoustic log P-wave and S-wave velocites利用声波测井纵波和横波速度估算气藏含水饱和度的方法摘要:The present application relates to new systems and methods of quantifying hydrocarbon saturation using measured acoustic logs.The methods and systems herein can accurately quantify the water saturation and hydrocarbon percentage in a low resistivity low contrast shaly sand reservoir where previous methods would indicate the reservoir was wet.In an embodiment,the disclosed system utilizes acoustic logging equipment or tools and techniques to transmit and/or record acoustic signals.Acoustic logging equipment operates by generating acoustic signals and detecting the acoustic signals after the acoustic signals pass through one or more geologic formations.展开更多
Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-eff...Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-effective geophysical technique can acquire high-density data;however,uncertainty and nonuniqueness inherent in ERT impede its usage for stratigraphy identification.This paper integrates ERT and onsite observations for the first time to propose a novel method for characterizing stratigraphic profiles.The method consists of two steps:(1)ERT for prior knowledge:ERT data are processed by soft clustering using the Gaussian mixture model,followed by probability smoothing to quantify its depthdependent uncertainty;and(2)Observations for calibration:a spatial sequential Bayesian updating(SSBU)algorithm is developed to update the prior knowledge based on likelihoods derived from onsite observations,namely topsoil and boreholes.The effectiveness of the proposed method is validated through its application to a real slope site in Foshan,China.Comparative analysis with advanced borehole-driven methods highlights the superiority of incorporating ERT data in stratigraphic modeling,in terms of prediction accuracy at borehole locations and sensitivity to borehole data.Informed by ERT,reduced sensitivity to boreholes provides a fundamental solution to the longstanding challenge of sparse measurements.The paper further discusses the impact of ERT uncertainty on the proposed model using time-lapse measurements,the impact of model resolution,and applicability in engineering projects.This study,as a breakthrough in stratigraphic modeling,bridges gaps in combining geophysical and geotechnical data to address measurement sparsity and paves the way for more economical geotechnical exploration.展开更多
Al_(65)Cu_(20)Fe_(15)bulk is synthesized with the high-pressure synthesis(HPS)method.Various analytical techniques,such as single crystal x-ray diffraction(SXRD),scanning electron microscopy equipped with energy-dispe...Al_(65)Cu_(20)Fe_(15)bulk is synthesized with the high-pressure synthesis(HPS)method.Various analytical techniques,such as single crystal x-ray diffraction(SXRD),scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy,and transmission electron microscopy,are employed to characterize the sintered bulk and confirmed its quasicrystalline structure.The electrical resistivity of the HPS quasicrystal specimen is measured from 2 K to 300 K,revealing a significantly elevated value in comparison to samples prepared via alternative methods.Nanoindentation testing demonstrates exceptional hardness and elastic modulus of our Al_(65)Cu_(20)Fe_(15)quasicrystal,consistent with existing results.The ratio of hardness to elastic modulus further highlight the potential superior wear resistance of the Al_(65)Cu_(20)Fe_(15)quasicrystal.Differential scanning calorimetry measurement conducted on the HPS Al_(65)Cu_(20)Fe_(15)quasicrystals reveal a high melting point of 877℃.展开更多
Spinel cubic ferrites have huge applications in me mory and high frequency devices.For the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the import...Spinel cubic ferrites have huge applications in me mory and high frequency devices.For the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important issues.This article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and 0.10.The X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSM),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the samples.The XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped samples.The densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu concentration.The FTIR analysis also proves the spinel cubic phase of the samples.The average grain size of the ferrites is obtained via FESEM images,and it is increased from 121 to 198 nm.VSM analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites.Particularly,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the ferrites.The permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric losses.Frequency dependent resistivity and impedance analysis also show the improved nature.From the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.展开更多
The Eastern Block of the North China Craton(NCC)(Fig.1)has undergone severe lithospheric destruction,with crustal thinning down to 100 km depth(Chen et al.,2009),contrasting sharply with the stable Kalahari and Rae cr...The Eastern Block of the North China Craton(NCC)(Fig.1)has undergone severe lithospheric destruction,with crustal thinning down to 100 km depth(Chen et al.,2009),contrasting sharply with the stable Kalahari and Rae cratons.However,there remains controversy over the destruction pattern(e.g.,Zhu et al.,2017).During the Early Mesozoic,crustal thickening occurred in the Xuhuai and Qinling orogens,followed by lithospheric delamination leading to crustal thinning(Chen et al.,2023).The middle and upper crustal thinning in the Yanshan and Taihang uplifts was induced by mafic magma underplating(Ji et al.,2009).展开更多
1.Introduction Electrodeposited copper is frequently employed as an electrical interconnection material in modern electronic devices owing to its superior conductivity and electromigration resistance[1,2].Reduc-ing th...1.Introduction Electrodeposited copper is frequently employed as an electrical interconnection material in modern electronic devices owing to its superior conductivity and electromigration resistance[1,2].Reduc-ing the electrical resistivity of Cu interconnects is an everlasting pursuit of the industry.For pure Cu,the primary approach to re-ducing its resistivity is to eliminate the crystal defects that scatter the electron transmission,especially grain boundaries(GBs).More-over,GBs are known to be the fast diffusion path for electromi-gration,which may lead to the formation of voids and protrusions[3,4].Therefore,efforts have been devoted to achieving large grains or even single crystals in Cu interconnects.展开更多
基金Sponsored by Jilin Provincial Department of Education Scientific Research Project(Grant Nos.JJKH20190875KJ,JJKH20230348KJ).
文摘This study tested the electrical conductivity and pressure sensitivity of lime⁃improved silty sand reinforced with Carbon Fiber Powder(CFP)as the conductive medium.The influence of CFP dosage,moisture content and curing duration on the unconfined compressive strength,initial resistivity and pressure sensitivity of the improved soil was systematically analysed.The results showed that the unconfined compressive strength varied non⁃monotonically with increasing CFP dosage,reaching a peak at a dosage of 1.6%.Furthermore,the initial resistivity showed slight variations under different moisture conditions but eventually converged towards the conductive percolation threshold at a dosage of 2.4%.It is worth noting that CFP reinforced lime⁃improved silty sand(CRLS)exhibit a clear dynamic synchronization of strain with stress and resistivity rate of variation.The pressure sensitivity was optimized with CFP dosages ranging from 1.6%to 2.0%.Both insufficient and excessive dosages had a negative impact on pressure sensitivity.It is important to consider the weakening effect of high moisture content on the pressure sensitivity of the specimens in practical applications.
基金financially supported by the National Natural Science Foundation of China(No.42277460)the Fundamental Research Project of Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences(No.SK202210).
文摘This study,based on Artificial Neural Network(ANN)technology,develops a quantitative prediction model for the unit water flow rate of the Quaternary strata in the Shijiazhuang-Hebei Plain area.The study area extends from the piedmont region of Shijiazhuang,at the eastern foothills of the Taihang Mountains,to the hinterland area of Hengshui within the plain in Hebei Province section of the North China Plain.The hydrological and exploration boreholes selected for modeling are primarily located in the south-eastern part of Shijiazhuang urban area—the southern region of Xinji County—north of Hengshui City near the Shenzhou County area.By employing the Induced Polarization method(IP)and Vertical Electrical Sounding(VES),apparent resistivity(ρS),apparent polarization rate(ηS),half-decay time(Th),and decay degree(D)were obtained as initial input parameters.These were combined with the measured water flow rates from borehole pumping tests to build the training sample set.To address the prevalent issue of high-salinity interference in the study area,multiple regression analysis revealed that when the inverted resistiv-ity(ρ)is less than 5Ω·m and the inverted polarization rate(η)is greater than 8%,the contribution of groundwater salinity to the resistivity parameter reaches 42%±6%.Based on this,a comprehensive parame-ter T"=ρ*H/ρ'was established,whereρis the aquifer resistivity,ρ'is the aquitard resistivity,and H is the aquifer thickness.The resistivity ratio effectively eliminates the coupling effect between electrical parame-ters and salinity.The input neurons of the improved model were adjusted to a four-parameter system consisting of decay time(Th),decay degree(D),deviation degree(σ),and the comprehensive parameter(T").Experiments showed that the prediction error of the model on the validation set was reduced from the original model's 5%-10%to 0.9%-5%.The introduction of the T"parameter reduced the prediction error in high salinity areas(Cl->500 mg/L)to within 7%.The study confirms that the composite parameter T"based on geophysical inversion parameters can effectively characterize the coupling features of aquifer thickness and water quality.Even with a small sample size,through algorithm optimization,data augmentation,and model structural improvements,it is entirely possible to effectively enhance prediction accuracy and gener-alization ability,providing a new parameterization method for the quantitative evaluation of Quaternary pore water in plain areas.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2021R1A2C1007400)supported,partly,by the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Nos.NRF-2020M3H4A3106383,NRF2020M3H4A3081764)+1 种基金supported,partly,by ETRI(No.21YB1610)supported by a Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(No.P0008458,HRD Program for Industrial Innovation)。
文摘Four types of submicron Ag-coated Cu particles with different Ag contents were prepared as sintering paste fillers,and the Ag contents of the particles were measured to be 10,20,30,and 40 wt.%.Four types of particles(in order of increasing Ag content:A10,A20,A30,and A40)were surface-modified with stearic acid,to suppress the Ag shell dewetting and improve sinterability.The surface-modified particles were mixed with a polyol-based solvent to fabricate a resin-free paste.Subsequently,the pastes were screen-printed onto a slide glass and sintered at 250°C in a nitrogen atmosphere for 1-10 min to form an electrode.The electrical resistivity of the sintered film as a function of sintering time was measured using a four-point probe.All the four surface-modified Cu@Ag particles with different Ag contents exhibited decreased electrical resistivity.Particularly,the largest difference in values after and before the surface modification was observed for A40 with the highest Ag content;the electrical resistivities of the initial and surface-modified particles were 1.51×10^(-4) and 6.67×10^(-5)Ω·cm,respectively,after sintering for 10 min.The findings of this study confirmed that the surface modification using stearic acid effectively suppressed the dewetting of the Ag shell and improved the sinterability of the submicron Cu@Ag particles.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274471,12404165,11922415,and 92165204)Guangzhou Science and Technology Programme(Grant Nos.2024A04J6415)+5 种基金the State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-Sen University,No.OEMT-2024-ZRC-02)the Key Laboratory of Magnetoelectric Physics and Devices of Guangdong Province(Grant No.2022B1212010008)the Research Center for Magnetoelectric Physics of Guangdong Province(Grant No.2024B0303390001)Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2401010)Lingyong Zeng acknowledges the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20233299)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.24qupy092)。
文摘This paper describes the synthesis and characterization of Nb_(2)TiW and Nb_(2)TiMo medium-entropy alloys(MEAs).The Nb_(2)TiW and Nb_(2)TiMo MEAs were successfully synthesized using the arc-melting method.Their structures and superconducting properties were investigated through detailed characterization using X-ray diffraction(XRD),resistivity,magnetization,and specific heat measurements.The XRD results confirmed that the obtained Nb_(2)TiW and Nb_(2)TiMo compounds have the same body-centered cubic(BCC)structure and crystallize in the Imˉ3m space group(number 229).Experimental results showed that the superconducting transition temperatures(Tcs)of Nb_(2)TiW and Nb_(2)TiMo are approximately 4.86 and 3.22 K,respectively.The upper and lower critical fields of Nb_(2)TiW are 3.52(2)T and 53.36(2)Oe,respectively,and those of Nb_(2)TiMo are 2.11(2)T and 68.23(3)Oe,respectively.First-principles calculations revealed that the d electrons of Nb,Ti,andMo orW are the dominant contributors to the density of states near the Fermi level.Specific heat measurement results indicated that Nb_(2)TiW and Nb_(2)TMo exhibit BCS full-gap s-wave superconductivity.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3901204)the Foundation for Distinguished Young Scholars of Hubei Province,China(Grant No.2021CFA096)the National Natural Science Foundation of China(Grant No.U20A20320).
文摘Evaluating the stabilized lead(Pb)-contaminated soils through sampling and laboratory testing involves costly and time-consuming processes.Therefore,this study employed a low-cost and non-destructive resistivity tool to evaluate the Pb-contaminated soils stabilized by electrolytic manganese residue(EMR)-based geopolymer(EG-OPC)from the strength and environmental benefits perspective.First,unconfined compressive strength(UCS)and leaching tests were conducted to study the stabilization effectiveness of EG-OPC.Results indicated that the UCS values of soil(5000 mg/kg of pollutants)stabilized by 20%EG-OPC were 4.87 MPa and 8.13 MPa after 7 d and 60 d of curing,respectively.After 60 d of curing,the Pb concentration in the leachate reached 44 mg/L,far lower than the control group(321 mg/L).Second,soil,pore water,and leachate resistivity(ERS,ERW,and ERL)were measured to establish fitting relationships with strength parameters and pollution risk.The good fitting results(e.g.ERS/ERW versus UCS/secant modulus(E50):correlation coefficient R2 z 0.9,ERS/ERW versus Pb contents:R2 z 0.9,and ERL versus Pb2þconcentration:R2¼0.92)and well used Archie's law(ERS versus ERW:R2>0.9)indicate that the resistivity can be used to evaluate the stabilization effectiveness.Furthermore,the microscopic results revealed two behaviors,demonstrating the reliability of resistivity:(1)with the hydration process,resistivity increases due to a denser structure and lower amounts of free water and Pb ions,and(2)the addition of Pb reduces resistivity due to its inhibition or even destructive effects on cementation and formation of hydration products.
文摘This study addresses the challenge of real-time resistivity gradient measurement in the Czochralski(CZ)silicon production process.Due to the inability to directly measure this parameter,we propose a Long Short-Term Memory soft-sensing model based on Convolutional Neural Network(CNN)and attention mechanism(CNN-ALSTM)that enhances traditional LSTM by integrating CNN and attention mechanism to overcome time lag variations during silicon pulling.The CNN module extracts spatial features from multi-source sensor data,while the attention-enhanced LSTM(ALSTM)dynamically adjusts historical parameter weights,enabling accurate resistivity gradient prediction.Experiments with real production data show that CNN-ALSTM outperforms SVR,FNN,RNN,XGBoost,and GRU,improving prediction accuracy by 11.76%,16.67%,21.05%,30.23%,and 9.09%,respectively.This soft-sensing approach enhances real-time monitoring and optimization of monocrystalline silicon growth.
基金financially supported by the National Natural Science Foundation of China(No.42376067)the Natural Science Foundation of Shandong Province(No.ZR202011030013)+1 种基金the Laoshan Laboratory(No.LSKJ202203506)the China Geological Survey Program(No.DD20230064)。
文摘Natural gas hydrates are widely distributed in marine and permafrost environments.As a novel energy resource,accurately describing reservoir characteristics and assessing energy potential is crucial for its commercial development.Resistivity logging serves as a valuable approach for achieving these goals.Nevertheless,due to inadequate comprehension of the electrical conductivity mechanism in hydrate-bearing sediments,existing data processing models still encounter certain challenges.This study conducts both core-scale and pore-scale simulation experiments to examine the relationship between resistivity variations and the distribution of gas hydrate porosity.The results indicate that the characteristics of resistivity variation is associated with the gas hydrate formation process,and the gas hydrate saturation index,denoted as‘n',varies between 0 and 3 depending on different gas hydrate distribution patterns.As the saturation increases,gas hydrate distribution in pore spaces transitions from floating to contacting and cementing patterns.It is proposed that the aqueous pore tortuosity can be utilized to correct the saturation index‘n'in Archie's equation.Based on the analysis of experimental data,a correction method for Archie's equation is suggested,and its effectiveness in controlling relative error has been validated.
基金National Natural Science Foundation of China(No.51705545)。
文摘To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing materials is proposed.Firstly,the sound absorption coefficients of a fibrous sound-absorbing material are measured at two different frequencies using the impedance tube method.Secondly,utilizing the empirical formulas for the wavenumber and acoustic impedance in the fibrous material,the flow resistivity and porosity of the sound-absorbing materials are calculated using the MATLAB cycle program.Thirdly,based on the values obtained through reverse calculations,the sound absorption coefficient,the real and the imaginary parts of the acoustic impedance of the sound-absorbing material at different frequencies are theoretically computed.Finally,the accuracy of these theoretical calculations is verified through experiments.The experimental results indicate that the calculated values are basically consistent with the measured values,demonstrating the feasibility and reliability of this method.
基金Projects(52279117,52325905)supported by the National Natural Science Foundation of ChinaProject(DJ-HXGG-2023-16)supported by the Technology Project of PowerChinaProject(SKLGME-JBGS2401)supported by the State Key Laboratory of Geomechanics and Geotechnical Engineering,China。
文摘During underground excavation,the surrounding rock mass is subjected to complex cyclic stress,significantly impacting its long-term stability,especially under varying water content conditions where this effect is amplified.However,research on the mechanical response mechanisms of surrounding rock mass under such conditions remains inadequate.This study utilized acoustic emission(AE)and resistivity testing to monitor rock fracture changes,revealing the rock’s damage state and characterizing the damage evolution process during uniaxial cyclic loading and unloading.First,a damage variable equation was established based on AE and resistivity parameters,leading to the derivation of a corresponding damage constitutive equation.Uniaxial cyclic loading and unloading tests were then conducted on sandstone samples with varying water contents,continuously monitoring AE signals and resistivity,along with computed tomography scans before and after failure.The predictions from the damage constitutive equation were compared with experimental results.This comparison shows that the proposed damage variable equation effectively characterizes the damage evolution of sandstone during loading and unloading,and that the constitutive equation closely fits the experimental data.This study provides a theoretical basis for monitoring and assessing the responses of surrounding rock mass during underground excavation.
基金Supported by National Key Research and Development Program of China(No.2023YFC3707901)。
文摘Evaluation of backfilling effectiveness plays a crucial role in the geological environment management and restoration of abandoned open-pit quarries,providing a scientific basis for subsequent greening efforts.Backfill soil,predominantly composed of silty clay,demonstrates high water retention capacity and elevated moisture content,leading to a pronounced resistivity contrast with the bedrock exposed by quarrying activities.To investigate the distribution of backfill soil subsurface and assess backfilling effectiveness in the study area,this study conducted a comprehensive geophysical investigation utilizing the high-density electrical resistivity tomography(ERT).A total of 19 ERT survey lines were deployed across three distinct areas in Liuyao Village,Huaibei City,Anhui Province,China.The inversion results,derived from both two-dimensional(2D)and three-dimensional(3D),reveal distinct electrical properties of the subsurface materials:the backfill soil layer shows low resistivity features,the fill stone layer exhibits medium to high resistivity,and the bedrock shows the highest resistivity.The 2D inversion results,from the data measured using the Wenner array effectively capture the spatial distribution and structural features of the backfill soil layer.The findings indicate a gradual east-west thinning of the clay layer within the quarry.Furthermore,the northern pit area exhibits a uniform distribution of backfill soil layer,indicative of effective backfilling operations.In contrast,the southern pit area lacks a well-defined clay layer,suggesting suboptimal backfilling effectiveness.
基金National Natural Science Foundation of China(No 52174048).
文摘Taking the Qihe area as an example,this paper compared various geophysical exploration methods in view of the problems of urban construction,deep thermal reservoir burial,and vast overlying low-resistance shield layer in deep karst geothermal exploration.A Controlledsource audio magnetotelluric(CSAMT)method was taken to overcome the problems and detect deep stratigraphic structures in the study area.The acquisition parameters of CSAMT were optimized to take into account the exploration depth and signal-to-noise ratio.The distortion of data in the near and transition zone was eliminated by the inversion of equivalent whole-region apparent resistivity,so as to achieve the purpose of deep sounding.Based on the resistivity profile resulting from the proposed CSAMT method,three faults were inferred and one low-resistance anomaly zone in the area was traced.The results of the profile interpretation were verified by drilling.The inferred stratigraphic boundaries and low-resistance anomaly zone were basically in agreement with the drilling results,thereby proving the eff ectiveness of the CSAMT method for deep geothermal exploration in low-resistance coverage areas.This method could provide technical support for deep geothermal exploration in similar areas.
基金supported by the National Natural Science Foundation of China(Nos.12222513 and 12405178)。
文摘The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the high gradient in the cryogenic photoinjector make it possible to improve the performance of new light sources.As an upgrading scheme for the Shanghai Soft X-ray Free-Electron Laser,this study explores a novel photocathode RF gun by introducing the TM_(02)mode into the cathode cell of a 2.6-cell electron gun,which improves the RF performance,particularly in terms of the monopole field.Furthermore,the optimized cathode cell with the TM_(02)mode can reduce the errors resulting from installation and decrease the dark current with alternative cathodes.In this study,the beam dynamics in a photoinjector were optimized using a 500-pC,5-ps beam,and its feasibility was examined.This paper presents the entire RF design process,including the adjustment of the RF structure,coupler design,local field,and multipole mode suppression to provide theoretical guidance for subsequent manufacturing and assembly.
基金supported by National Key R&D Program of China(2022YFB3605103)National Natural Science Foundation of China(62425408,62121005,U22A2084,12234018)+2 种基金Youth Innovation Promotion Association of the Chinese Academy of Sciences(2023223)Natural Science Foundation of Jilin Province(20230101345JC,20230101360JC,SKL202302026)Young Elite Scientist Sponsorship Program by CAST(YESS20200182).
文摘AlGaN-based LEDs with peak wavelength below 240 nm(far-UVC)pose no significant harm to human health,thus highlighting their broader application potential.While,there is a significant Schottky barrier between the n-electrode and Alrich n-AlGaN,adversely impeding electron injection and resulting in considerable heat generation.Here,we fabricate V-based electrodes of V/Al/Ti/Au on n-AlGaN with Al content over 80%and investigate the relationship between the metal diffusion and contact properties during the high-temperature annealing process.Experiments reveal that decreasing V thickness in the electrode promotes the diffusion of Al towards the surface of n-AlGaN,which facilitates the formation of VN and thus the increase of local electron concentration,resulting in lower specific contact resistivity.Then,increasing the Al thickness inhibits the diffusion of Au to the n-AlGaN surface,suppressing the rise of Schottky barrier.Experimentally,an optimized n-electrode of V(10 nm)/Al(240 nm)/Ti(40 nm)/Au(50 nm)on n-Al_(0.81)Ga_(0.19)N is obtained,realizing an optimal specific contact resistivity of 7.30×10^(−4)Ω·cm^(2).Based on the optimal n-electrode preparation scheme for Al-rich n-AlGaN,the work voltage of a far-UVC LED with peak wavelength of 233.5 nm is effectively reduced.
基金support from the National Key R&D Program of China(2021YFC3001003)Guangdong Provincial Department of Science and Technology(2022A0505030019)Science and Technology Development Fund,Macao SAR(File nos.0056/2023/RIB2,001/2024/SKL).
文摘Characterization of vegetation effect on soil response is essential for comprehending site-specific hydrological processes.Traditional research often relies on sensors or remote sensing data to examine the hydrological properties of vegetation zones,yet these methods are limited by either measurement sparsity or spatial inaccuracy.Therefore,this paper is the first to propose a data-driven approach that incorporates high-temporal-resolution electrical resistivity tomography(ERT)to quantify soil hydrological response.Time-lapse ERT is deployed on a vegetated slope site in Foshan,China,during a discontinuous rainfall induced by Typhoon Haikui.A total of 97 ERT measurements were collected with an average time interval of 2.7 hours.The Gaussian Mixture Model(GMM)is applied to quantify the level of response and objectively classify impact zones based on features extracted directly from the ERT data.The resistivity-moisture content correlation is established based on on-site sensor data to characterize infiltration and evapotranspiration across wet-dry conditions.The findings are compared with the Normalized Difference Vegetation Index(NDVI),a common indicator for vegetation quantification,to reveal potential spatial errors in remote sensing data.In addition,this study provides discussions on the potential applications and future directions.This paper showcases significant spatio-temporal advantages over existing studies,providing a more detailed and accurate characterization of superficial soil hydrological response.
文摘公开(公告)号:US12242011B2 Method for estimating water saturation in gas reservoirs using acoustic log P-wave and S-wave velocites利用声波测井纵波和横波速度估算气藏含水饱和度的方法摘要:The present application relates to new systems and methods of quantifying hydrocarbon saturation using measured acoustic logs.The methods and systems herein can accurately quantify the water saturation and hydrocarbon percentage in a low resistivity low contrast shaly sand reservoir where previous methods would indicate the reservoir was wet.In an embodiment,the disclosed system utilizes acoustic logging equipment or tools and techniques to transmit and/or record acoustic signals.Acoustic logging equipment operates by generating acoustic signals and detecting the acoustic signals after the acoustic signals pass through one or more geologic formations.
基金the financial support from the National Key R&D Program of China(Grant No.2021YFC3001003)Science and Technology Development Fund,Macao SAR(File No.0056/2023/RIB2)Guangdong Provincial Department of Science and Technology(Grant No.2022A0505030019).
文摘Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-effective geophysical technique can acquire high-density data;however,uncertainty and nonuniqueness inherent in ERT impede its usage for stratigraphy identification.This paper integrates ERT and onsite observations for the first time to propose a novel method for characterizing stratigraphic profiles.The method consists of two steps:(1)ERT for prior knowledge:ERT data are processed by soft clustering using the Gaussian mixture model,followed by probability smoothing to quantify its depthdependent uncertainty;and(2)Observations for calibration:a spatial sequential Bayesian updating(SSBU)algorithm is developed to update the prior knowledge based on likelihoods derived from onsite observations,namely topsoil and boreholes.The effectiveness of the proposed method is validated through its application to a real slope site in Foshan,China.Comparative analysis with advanced borehole-driven methods highlights the superiority of incorporating ERT data in stratigraphic modeling,in terms of prediction accuracy at borehole locations and sensitivity to borehole data.Informed by ERT,reduced sensitivity to boreholes provides a fundamental solution to the longstanding challenge of sparse measurements.The paper further discusses the impact of ERT uncertainty on the proposed model using time-lapse measurements,the impact of model resolution,and applicability in engineering projects.This study,as a breakthrough in stratigraphic modeling,bridges gaps in combining geophysical and geotechnical data to address measurement sparsity and paves the way for more economical geotechnical exploration.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52173231 and 51925105)the Natural Science Foundation of Hebei Province,China(Grant No.E2022203182)+1 种基金The Innovation Ability Promotion Project of Hebei supported by Hebei Key Laboratory for Optimizing Metal Product Technology and Performance(Grant No.22567609H)supported by the grants from Slovak National Agencies(Grant Nos.VEGA 2/0144/21,APVV19-0369,and APVV-20-0124)。
文摘Al_(65)Cu_(20)Fe_(15)bulk is synthesized with the high-pressure synthesis(HPS)method.Various analytical techniques,such as single crystal x-ray diffraction(SXRD),scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy,and transmission electron microscopy,are employed to characterize the sintered bulk and confirmed its quasicrystalline structure.The electrical resistivity of the HPS quasicrystal specimen is measured from 2 K to 300 K,revealing a significantly elevated value in comparison to samples prepared via alternative methods.Nanoindentation testing demonstrates exceptional hardness and elastic modulus of our Al_(65)Cu_(20)Fe_(15)quasicrystal,consistent with existing results.The ratio of hardness to elastic modulus further highlight the potential superior wear resistance of the Al_(65)Cu_(20)Fe_(15)quasicrystal.Differential scanning calorimetry measurement conducted on the HPS Al_(65)Cu_(20)Fe_(15)quasicrystals reveal a high melting point of 877℃.
基金supported by the Research and Innovation Centre,Khulna University(KURC ID-47/2020)。
文摘Spinel cubic ferrites have huge applications in me mory and high frequency devices.For the improvement of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important issues.This article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites,where x=0.00,0.06,and 0.10.The X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSM),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the samples.The XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped samples.The densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increment of rare earth Eu concentration.The FTIR analysis also proves the spinel cubic phase of the samples.The average grain size of the ferrites is obtained via FESEM images,and it is increased from 121 to 198 nm.VSM analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)Ni_(0.5)Eu_(x)Fe_(2-x)O_(4) ferrites.Particularly,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contamination in the ferrites.The permeability and dielectric measurements show an improved quality factor of the Eu-doped samples with low magnetic and dielectric losses.Frequency dependent resistivity and impedance analysis also show the improved nature.From the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.
基金granted by the National Key R&D Plan(Grant No.2022YFF0800702)project SINOPROBE on sub-project SINOPROBE-01,National Natural Science Foundation of China(Grants 41274003,41674101,and 41974112)。
文摘The Eastern Block of the North China Craton(NCC)(Fig.1)has undergone severe lithospheric destruction,with crustal thinning down to 100 km depth(Chen et al.,2009),contrasting sharply with the stable Kalahari and Rae cratons.However,there remains controversy over the destruction pattern(e.g.,Zhu et al.,2017).During the Early Mesozoic,crustal thickening occurred in the Xuhuai and Qinling orogens,followed by lithospheric delamination leading to crustal thinning(Chen et al.,2023).The middle and upper crustal thinning in the Yanshan and Taihang uplifts was induced by mafic magma underplating(Ji et al.,2009).
基金sponsored by the National Natural Science Foun-dation of China(Nos.62004124,22372100,and 51991374).
文摘1.Introduction Electrodeposited copper is frequently employed as an electrical interconnection material in modern electronic devices owing to its superior conductivity and electromigration resistance[1,2].Reduc-ing the electrical resistivity of Cu interconnects is an everlasting pursuit of the industry.For pure Cu,the primary approach to re-ducing its resistivity is to eliminate the crystal defects that scatter the electron transmission,especially grain boundaries(GBs).More-over,GBs are known to be the fast diffusion path for electromi-gration,which may lead to the formation of voids and protrusions[3,4].Therefore,efforts have been devoted to achieving large grains or even single crystals in Cu interconnects.
