Theoretical calculations serve as an effective method for determining plasma temperatures within planetary atmospheres.To simulate plasma temperature,a comprehensive implementation of the energy equation is used,which...Theoretical calculations serve as an effective method for determining plasma temperatures within planetary atmospheres.To simulate plasma temperature,a comprehensive implementation of the energy equation is used,which is governed by five terms:conductivity,heating,cooling,adiabatic expansion,and advection.The derivations mentioned are strongly dependent on the collision cross section between electrons and other particles(e.g.,neutrals,ions).It is notable that the momentum transfer cross sections between electrons and neutrals have been updated in recent decades.However,the widely used momentum average collision cross sections between electrons and neutrals,derived from the momentum transfer cross sections,are collected in studies dating back nearly half a century.Therefore,it becomes imperative to revise the momentum average collision cross sections relevant to astrophysical contexts,based on the latest studies.In this study,we summarize the momentum average collision cross sections of 13 species common in planetary atmospheres:H,H_(2),He,O,CH_(4),H_(2)O,CO,N_(2),O_(2),Ar,CO_(2),N_(2)O,and NO_(2).All results are derived from the latest studies concerning the electron-neutral collision cross section and are compared with previous studies.Furthermore,we present a comparison of the derived total electron-neutral collision frequency at Mars between this study and previous studies.Prominent differences in the total electron-neutral collision frequency between this and prior studies support the significance of updating the momentum average collision cross section between electrons and neutrals in studying the planetary atmospheres.展开更多
Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sust...Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sustainable development.Despite significant progress in various electrochemical systems,the regulatory mechanisms of PDE in energy and mass transfer and the lifespan extension of electrolysis systems,particularly in water electrolysis(WE)for hydrogen production,remain insufficiently explored.Therefore,there is an urgent need for a deeper understanding of the unique contributions of PDE in mass transfer enhancement,microenvironment regulation,and hydrogen production optimization,aiming to achieve low-energy consumption,high catalytic activity,and long-term stability in the generation of target products.Here,this review critically examines the microenvironmental effects of PDE on energy and mass transfer,the electrode degradation mechanisms in the lifespan extension of electrolysis systems,and the key factors in enhancing WE for hydrogen production,providing a comprehensive summary of current research progress.The review focuses on the complex regulatory mechanisms of frequency,duty cycle,amplitude,and other factors in hydrogen evolution reaction(HER)performance within PDE strategies,revealing the interrelationships among them.Finally,the potential future directions and challenges for transitioning from laboratory studies to industrial applications are proposed.展开更多
The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising c...The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.展开更多
Chemical exchange saturation transfer magnetic resonance imaging is an advanced imaging technique that enables the detection of compounds at low concentrations with high sensitivity and spatial resolution and has been...Chemical exchange saturation transfer magnetic resonance imaging is an advanced imaging technique that enables the detection of compounds at low concentrations with high sensitivity and spatial resolution and has been extensively studied for diagnosing malignancy and stroke.In recent years,the emerging exploration of chemical exchange saturation transfer magnetic resonance imaging for detecting pathological changes in neurodegenerative diseases has opened up new possibilities for early detection and repetitive scans without ionizing radiation.This review serves as an overview of chemical exchange saturation transfer magnetic resonance imaging with detailed information on contrast mechanisms and processing methods and summarizes recent developments in both clinical and preclinical studies of chemical exchange saturation transfer magnetic resonance imaging for Alzheimer’s disease,Parkinson’s disease,multiple sclerosis,and Huntington’s disease.A comprehensive literature search was conducted using databases such as PubMed and Google Scholar,focusing on peer-reviewed articles from the past 15 years relevant to clinical and preclinical applications.The findings suggest that chemical exchange saturation transfer magnetic resonance imaging has the potential to detect molecular changes and altered metabolism,which may aid in early diagnosis and assessment of the severity of neurodegenerative diseases.Although promising results have been observed in selected clinical and preclinical trials,further validations are needed to evaluate their clinical value.When combined with other imaging modalities and advanced analytical methods,chemical exchange saturation transfer magnetic resonance imaging shows potential as an in vivo biomarker,enhancing the understanding of neuropathological mechanisms in neurodegenerative diseases.展开更多
Mitochondria play a crucial role as organelles,managing several physiological processes such as redox balance,cell metabolism,and energy synthesis.Initially,the assumption was that mitochondria primarily resided in th...Mitochondria play a crucial role as organelles,managing several physiological processes such as redox balance,cell metabolism,and energy synthesis.Initially,the assumption was that mitochondria primarily resided in the host cells and could exclusively transmit from oocytes to offspring by a mechanism known as vertical inheritance of mitochondria.Recent scholarly works,however,suggest that certain cell types transmit their mitochondria to other developmental cell types via a mechanism referred to as intercellular or horizontal mitochondrial transfer.This review details the process of which mitochondria are transferred across cells and explains the impact of mitochondrial transfer between cells on the efficacy and functionality of cancer cells in various cancer forms.Specifically,we review the role of mitochondria transfer in regulating cellular metabolism restoration,excess reactive oxygen species(ROS)generation,proliferation,invasion,metastasis,mitophagy activation,mitochondrial DNA(mtDNA)inheritance,immune system modulation and therapeutic resistance in cancer.Additionally,we highlight the possibility of using intercellular mitochondria transfer as a therapeutic approach to treat cancer and enhance the efficacy of cancer treatments.展开更多
Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a b...Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a binary nanophotocatalyst fabricated by blending two polymers,PS-PEG5(PS)and PBT-PEG5(PBT),with matched absorption and emission spectra,enabling a Forster resonance energy transfer(FRET)process for enhanced photocatalysis.These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation(FNP)technique with precious kinetic control over binary nanoparticle formation.The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g^(-1) h^(-1),2.5 times higher than that single component nanoparticles.Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles,which prolongs the excited-state lifetime and extends the namely“effective exciton diffusion length”.Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.展开更多
In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant ...In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant statistical fluctuations.These issues can lead to potential failures in peak-searching-based identification methods.To address the low precision associated with short-duration measurements of radionuclides,this paper proposes an identification algorithm that leverages heterogeneous spectral transfer to develop a low-count energy spectral identification model.Comparative experiments demonstrated that transferring samples from 26 classes of simulated heterogeneous gamma spectra aids in creating a reliable model for measured gamma spectra.With only 10%of target domain samples used for training,the accuracy on real low-count spectral samples was 95.56%.This performance shows a significant improvement over widely employed full-spectrum analysis methods trained on target domain samples.The proposed method also exhibits strong generalization capabilities,effectively mitigating overfitting issues in low-count energy spectral classification under short-duration measurements.展开更多
Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficul...Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficult recovery of the catalysts in a powdery form.Herein,a three-dimensional(3D)framework of Fe-incorporated Ni_(3)S_(2)nanosheets in-situ grown on Ni foam(Fe-Ni_(3)S_(2)@NF)was fabricated by a facile two-step hydrothermal process and applied to trigger peroxymonosulfate(PMS)oxidation of organic compounds inwater.A homogeneous growth environment enabled the uniform and scalable growth of Fe-Ni_(3)S_(2)nanosheets on the Ni foam.Fe-Ni_(3)S_(2)@NF possessed outstanding activity and durability in activating PMS,as it effectively facilitated electron transfer from organic pollutants to PMS.Fe-Ni_(3)S_(2)@NF initially supplied electrons to PMS,causing the catalyst to undergo oxidation,and subsequently accepted electrons from organic compounds,returning to its initial state.The introduction of Fe into the Ni_(3)S_(2)lattice enhanced electrical conductivity,promoting mediated electron transfer between PMS and organic compounds.The 3D conductive Ni foam provided an ideal platform for the nucleation and growth of Fe-Ni_(3)S_(2),accelerating pollutant abatement due to its porous structure and high conductivity.Furthermore,its monolithic nature simplified the catalyst recycling process.A continuous flow packed-bed reactor by encapsulating Fe-Ni_(3)S_(2)@NF catalyst achieved complete pollutant abatement with continuous operation for 240 h,highlighting its immense potential for practical environmental remediation.This study presents a facile synthesis method for creating a novel type of monolithic catalyst with high activity and durability for decontamination through Fenton-like processes.展开更多
Layered double hydroxide(LDH)based heterogonous peroxymonosulfate(PMS)activation degradation of pollutants has attracted extensive attention.The challenge is to selectively regulate the traditional free radical domina...Layered double hydroxide(LDH)based heterogonous peroxymonosulfate(PMS)activation degradation of pollutants has attracted extensive attention.The challenge is to selectively regulate the traditional free radical dominant degradation pathway into a nonradical degradation pathway.Herein,an interface ar-chitecture of Ti_(3) C_(2) T_(x)-MXene(MXene)loading on the Fe-Al LDH scaffold was developed,which showed excellent stability and robust resistance against harsh conditions.Significantly,the rate constant for tetra-cycline hydrochloride(TC)degradation in the MXene-LDH/PMS process was 0.421 min^(-1),which was ten times faster than the rate constant for pure Fe-Al LDH(0.042 min^(-1)).Specifically,more reactive Fe with the closer d-band center to the Fermi level results in higher electron transfer efficiency.The occupa-tions of Fe-3d orbitals in Mxene/Fe-Al LDH are pushed above the Fermi level to generate,which results in higher PMS adsorption and inhibition of the release of oxygen-containing active species intermedi-ates,leading to the enhanced^(1)O_(2) generation.Additionally,the built-in electric field in the heterojunc-tion was driven by the charge redistribution between MXene and Fe-Al LDH,resulting in a mediated-electron transfer mechanism,differentiating it from the Fe-Al LDH/PMS system.It was fascinating that MXene/Fe-Al LDH achieved satisfactory treatment efficiency in continuous column reactor and real landfill leachate.展开更多
The current deep learning models for braced excavation cannot predict deformation from the beginning of excavation due to the need for a substantial corpus of sufficient historical data for training purposes.To addres...The current deep learning models for braced excavation cannot predict deformation from the beginning of excavation due to the need for a substantial corpus of sufficient historical data for training purposes.To address this issue,this study proposes a transfer learning model based on a sequence-to-sequence twodimensional(2D)convolutional long short-term memory neural network(S2SCL2D).The model can use the existing data from other adjacent similar excavations to achieve wall deflection prediction once a limited amount of monitoring data from the target excavation has been recorded.In the absence of adjacent excavation data,numerical simulation data from the target project can be employed instead.A weight update strategy is proposed to improve the prediction accuracy by integrating the stochastic gradient masking with an early stopping mechanism.To illustrate the proposed methodology,an excavation project in Hangzhou,China is adopted.The proposed deep transfer learning model,which uses either adjacent excavation data or numerical simulation data as the source domain,shows a significant improvement in performance when compared to the non-transfer learning model.Using the simulation data from the target project even leads to better prediction performance than using the actual monitoring data from other adjacent excavations.The results demonstrate that the proposed model can reasonably predict the deformation with limited data from the target project.展开更多
在智能反射面(Intelligent Reflective Surface,IRS)辅助的多天线车联网中,性能增益通常是在天线硬件完善的情况下实现,但实际的天线硬件缺陷可能会降低这些增益。在考虑天线硬件损伤的情况下,针对IRS辅助的多输入单输出(Multiple-Input...在智能反射面(Intelligent Reflective Surface,IRS)辅助的多天线车联网中,性能增益通常是在天线硬件完善的情况下实现,但实际的天线硬件缺陷可能会降低这些增益。在考虑天线硬件损伤的情况下,针对IRS辅助的多输入单输出(Multiple-Input Single-Output,MISO)下行车联网无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)系统,提出了一种主动式和被动式联合的波束赋形设计方法。在信干噪比、最小接收能量阈值、IRS相移等约束条件下,以最小化基站发射总功率为目标,运用半定松弛(Semidefinite Relaxation,SDR)、矩阵分析理论等方法,将具有耦合变量的非凸优化问题转化成解耦后的凸优化问题,并用交替迭代优化算法来求得原问题的解。仿真结果表明,在车联网SWIPT系统中考虑硬件损伤的必要性和IRS辅助的有效性,并给出了算法的收敛性和车速、IRS反射单元数等系统参数对系统性能的影响。展开更多
In radiology,magnetic resonance imaging(MRI)is an essential diagnostic tool that provides detailed images of a patient’s anatomical and physiological structures.MRI is particularly effective for detecting soft tissue...In radiology,magnetic resonance imaging(MRI)is an essential diagnostic tool that provides detailed images of a patient’s anatomical and physiological structures.MRI is particularly effective for detecting soft tissue anomalies.Traditionally,radiologists manually interpret these images,which can be labor-intensive and time-consuming due to the vast amount of data.To address this challenge,machine learning,and deep learning approaches can be utilized to improve the accuracy and efficiency of anomaly detection in MRI scans.This manuscript presents the use of the Deep AlexNet50 model for MRI classification with discriminative learning methods.There are three stages for learning;in the first stage,the whole dataset is used to learn the features.In the second stage,some layers of AlexNet50 are frozen with an augmented dataset,and in the third stage,AlexNet50 with an augmented dataset with the augmented dataset.This method used three publicly available MRI classification datasets:Harvard whole brain atlas(HWBA-dataset),the School of Biomedical Engineering of Southern Medical University(SMU-dataset),and The National Institute of Neuroscience and Hospitals brain MRI dataset(NINS-dataset)for analysis.Various hyperparameter optimizers like Adam,stochastic gradient descent(SGD),Root mean square propagation(RMS prop),Adamax,and AdamW have been used to compare the performance of the learning process.HWBA-dataset registers maximum classification performance.We evaluated the performance of the proposed classification model using several quantitative metrics,achieving an average accuracy of 98%.展开更多
Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up ...Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.展开更多
Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a...Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.展开更多
Element Transfer Reaction(ETR)theory is a new fundamental theory guiding the design of synthetic routes.It analyses problems from a brand-new perspective of element circulation,decomposing the factors affecting synthe...Element Transfer Reaction(ETR)theory is a new fundamental theory guiding the design of synthetic routes.It analyses problems from a brand-new perspective of element circulation,decomposing the factors affecting synthetic efficiency into three elements:element sources,driving force,and output.Different from the retrosynthetic analysis method and the atom economy theory,the ETR theory places more emphasis on examining the problem as a whole and comprehensively considering various factors involved in industrial applications.This perspective intends to elaborate on the scientific connotation of the ETR theory and explore its characteristics by discussing the practical application cases.展开更多
Photocatalytic hydrogen production technology is an ideal approach to addressing energy and environmental issues,with efficient charge transfer being the key to achieving high-performance hydrogen production.Ultra-thi...Photocatalytic hydrogen production technology is an ideal approach to addressing energy and environmental issues,with efficient charge transfer being the key to achieving high-performance hydrogen production.Ultra-thin CuInS_(2)nanosheets were prepared through a solvothermal method.Subsequently,metallic Ni was surface-modified onto CuInS_(2)through photo-deposition to serve as a co-catalyst.The optimized photocatalyst exhibited a hydrogen production rate of 15.5 mmol·g^(-1)·h^(-1)in water when used an ascorbic acid as hole scavenger,which is 9 times that of the original CuInS_(2).Transient absorption spectra(TAS)analysis demonstrates that the hole transfer from CuInS_(2)nanosheets to ascorbic acid,yielding a long-lived electron with a lifetime of 45.6μs.The electrons in CuInS_(2)are efficiently captured by Ni as active sites for driving hydrogen evolution.In situ TAS further indicates that ascorbic acid and Ni sites synergistically promote the electron transfer dynamics of CuInS_(2),achieving an electron transfer efficiency of 48.4%.This work provides a viable strategy for designing highly efficient photocatalysts with enhanced charge transfer.展开更多
Inorganic lead-free double perovskites have the advantages of low toxicity,broadband emission,and good stability,which make them promising luminescent materials for lighting applications.However,due to the limited reg...Inorganic lead-free double perovskites have the advantages of low toxicity,broadband emission,and good stability,which make them promising luminescent materials for lighting applications.However,due to the limited regulation of their self-trapped exciton emission,it is still greatly challenging to achieve white light emitting from a single double perovskite host.Herein,efficient and tunable white light is realized in Cs_(2)NalnCl_(6)∶Sb^(3+),Tb^(3+),Sm^(3+)double perovskite by controlling the ratios of the doped three ions with blue,green,and red emissions,respectively.The steady-state and transient fluorescence spectra of singly-and doubly-doped double perovskites reveal the existence of multiple energy transfer channels in the triply-doped phosphors,including from Sb^(3+)to Tb^(3+),Sb^(3+)to Sm^(3+),and Tb^(3+)to Sm^(3+).Benefiting from these channels,the color coordinates of the triply-doped phosphors can cross the whole white light area of the CIE chromaticity diagram by adjusting the ratios of the three dopants,and the maximum internal quantum yield of the white light phosphors is 66.61%.The white emission phosphors show the characteristic of being independent of excitation wavelength within 310-360 nm.Furthermore,the emission intensity at 430 K of the white light phosphor Cs_(2)NalnCl_(6)∶0.01Sb^(3+),0.65Tb^(3+),0.20Sm^(3+)remains 50% of that at room temperature.A WLED device fabricated with the phosphor and a 365 nm LED chip exhibits a high color rendering index of 90.9,correlated color temperature of 5469 K,and CIE coordinates of(0.333 and 0.328).The results indicate that the as-prepared double perovskite materials are promising candidates in the solid-state lighting field.展开更多
基金the National Natural Science Foundation of China through Grants 42261160643,42441806,42241114,and 42304166supported by the open project funded by the Key Laboratory of Geospace Environment,Chinese Academy of Sciences,University of Science and Technology of China.
文摘Theoretical calculations serve as an effective method for determining plasma temperatures within planetary atmospheres.To simulate plasma temperature,a comprehensive implementation of the energy equation is used,which is governed by five terms:conductivity,heating,cooling,adiabatic expansion,and advection.The derivations mentioned are strongly dependent on the collision cross section between electrons and other particles(e.g.,neutrals,ions).It is notable that the momentum transfer cross sections between electrons and neutrals have been updated in recent decades.However,the widely used momentum average collision cross sections between electrons and neutrals,derived from the momentum transfer cross sections,are collected in studies dating back nearly half a century.Therefore,it becomes imperative to revise the momentum average collision cross sections relevant to astrophysical contexts,based on the latest studies.In this study,we summarize the momentum average collision cross sections of 13 species common in planetary atmospheres:H,H_(2),He,O,CH_(4),H_(2)O,CO,N_(2),O_(2),Ar,CO_(2),N_(2)O,and NO_(2).All results are derived from the latest studies concerning the electron-neutral collision cross section and are compared with previous studies.Furthermore,we present a comparison of the derived total electron-neutral collision frequency at Mars between this study and previous studies.Prominent differences in the total electron-neutral collision frequency between this and prior studies support the significance of updating the momentum average collision cross section between electrons and neutrals in studying the planetary atmospheres.
基金financially supported by the Key Research and Development Program of Heilongjiang Province(No.2024ZXJ03C06)National Natural Science Foundation of China(No.52476192,No.52106237)+1 种基金Natural Science Foundation of Heilongjiang Province(No.YQ2022E027)Technology Project of China Datang Technology Innovation Co.,Ltd(No.DTKC-2024-20610).
文摘Pulsed dynamic electrolysis(PDE),driven by renewable energy,has emerged as an innovative electrocatalytic conversion method,demonstrating significant potential in addressing global energy challenges and promoting sustainable development.Despite significant progress in various electrochemical systems,the regulatory mechanisms of PDE in energy and mass transfer and the lifespan extension of electrolysis systems,particularly in water electrolysis(WE)for hydrogen production,remain insufficiently explored.Therefore,there is an urgent need for a deeper understanding of the unique contributions of PDE in mass transfer enhancement,microenvironment regulation,and hydrogen production optimization,aiming to achieve low-energy consumption,high catalytic activity,and long-term stability in the generation of target products.Here,this review critically examines the microenvironmental effects of PDE on energy and mass transfer,the electrode degradation mechanisms in the lifespan extension of electrolysis systems,and the key factors in enhancing WE for hydrogen production,providing a comprehensive summary of current research progress.The review focuses on the complex regulatory mechanisms of frequency,duty cycle,amplitude,and other factors in hydrogen evolution reaction(HER)performance within PDE strategies,revealing the interrelationships among them.Finally,the potential future directions and challenges for transitioning from laboratory studies to industrial applications are proposed.
基金financial support from 2024 Domestic Visiting Scholar Program for Teachers'Professional Development in Universities(Grant No.FX2024022)National Natural Science Foundation of China(Grant No.61904043)。
文摘The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.
基金supported by The University of Hong Kong,China(109000487,109001694,204610401,and 204610519)National Natural Science Foundation of China(82402225)(to JH).
文摘Chemical exchange saturation transfer magnetic resonance imaging is an advanced imaging technique that enables the detection of compounds at low concentrations with high sensitivity and spatial resolution and has been extensively studied for diagnosing malignancy and stroke.In recent years,the emerging exploration of chemical exchange saturation transfer magnetic resonance imaging for detecting pathological changes in neurodegenerative diseases has opened up new possibilities for early detection and repetitive scans without ionizing radiation.This review serves as an overview of chemical exchange saturation transfer magnetic resonance imaging with detailed information on contrast mechanisms and processing methods and summarizes recent developments in both clinical and preclinical studies of chemical exchange saturation transfer magnetic resonance imaging for Alzheimer’s disease,Parkinson’s disease,multiple sclerosis,and Huntington’s disease.A comprehensive literature search was conducted using databases such as PubMed and Google Scholar,focusing on peer-reviewed articles from the past 15 years relevant to clinical and preclinical applications.The findings suggest that chemical exchange saturation transfer magnetic resonance imaging has the potential to detect molecular changes and altered metabolism,which may aid in early diagnosis and assessment of the severity of neurodegenerative diseases.Although promising results have been observed in selected clinical and preclinical trials,further validations are needed to evaluate their clinical value.When combined with other imaging modalities and advanced analytical methods,chemical exchange saturation transfer magnetic resonance imaging shows potential as an in vivo biomarker,enhancing the understanding of neuropathological mechanisms in neurodegenerative diseases.
基金supported by the National Natural Science Foundation of China(Grant No.:82272749)the Natural Science Foundation of Liaoning Province,China(Grant No.:2022-MS-190).
文摘Mitochondria play a crucial role as organelles,managing several physiological processes such as redox balance,cell metabolism,and energy synthesis.Initially,the assumption was that mitochondria primarily resided in the host cells and could exclusively transmit from oocytes to offspring by a mechanism known as vertical inheritance of mitochondria.Recent scholarly works,however,suggest that certain cell types transmit their mitochondria to other developmental cell types via a mechanism referred to as intercellular or horizontal mitochondrial transfer.This review details the process of which mitochondria are transferred across cells and explains the impact of mitochondrial transfer between cells on the efficacy and functionality of cancer cells in various cancer forms.Specifically,we review the role of mitochondria transfer in regulating cellular metabolism restoration,excess reactive oxygen species(ROS)generation,proliferation,invasion,metastasis,mitophagy activation,mitochondrial DNA(mtDNA)inheritance,immune system modulation and therapeutic resistance in cancer.Additionally,we highlight the possibility of using intercellular mitochondria transfer as a therapeutic approach to treat cancer and enhance the efficacy of cancer treatments.
基金supported by National Natural Science Foundation of China(NSFC,22338006,92356301,9235630033 and 22375062)Shanghai Municipal Science and Technology Major Project(21JC1401700)+4 种基金Shanghai Pilot Program for Basic Research(22TQ1400100-10)Fundamental Research Funds for the Central UniversitiesShanghai Pujiang Program(22PJ1402400)“Chenguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(22CGA32)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001).
文摘Organic nanophotocatalysts are promising candidates for solar fuels production,but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths.Here,we introduce a binary nanophotocatalyst fabricated by blending two polymers,PS-PEG5(PS)and PBT-PEG5(PBT),with matched absorption and emission spectra,enabling a Forster resonance energy transfer(FRET)process for enhanced photocatalysis.These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation(FNP)technique with precious kinetic control over binary nanoparticle formation.The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g^(-1) h^(-1),2.5 times higher than that single component nanoparticles.Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles,which prolongs the excited-state lifetime and extends the namely“effective exciton diffusion length”.Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.
基金supported by the National Defense Fundamental Research Project(No.JCKY2022404C005)the Nuclear Energy Development Project(No.23ZG6106)+1 种基金the Sichuan Scientific and Technological Achievements Transfer and Transformation Demonstration Project(No.2023ZHCG0026)the Mianyang Applied Technology Research and Development Project(No.2021ZYZF1005)。
文摘In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant statistical fluctuations.These issues can lead to potential failures in peak-searching-based identification methods.To address the low precision associated with short-duration measurements of radionuclides,this paper proposes an identification algorithm that leverages heterogeneous spectral transfer to develop a low-count energy spectral identification model.Comparative experiments demonstrated that transferring samples from 26 classes of simulated heterogeneous gamma spectra aids in creating a reliable model for measured gamma spectra.With only 10%of target domain samples used for training,the accuracy on real low-count spectral samples was 95.56%.This performance shows a significant improvement over widely employed full-spectrum analysis methods trained on target domain samples.The proposed method also exhibits strong generalization capabilities,effectively mitigating overfitting issues in low-count energy spectral classification under short-duration measurements.
基金supported by the National Natural Science Foundation of China(No.21876039)Y.Yao acknowledges the scholarship support from the China Scholarship Council(No.202106695010)Partial support from the Australian Research Council for DP230102406 is also acknowledged.
文摘Catalytic oxidation of organic pollutants is a well-known and effective technique for pollutant abatement.Unfortunately,this method is significantly hindered in practical applications by the lowefficiency and difficult recovery of the catalysts in a powdery form.Herein,a three-dimensional(3D)framework of Fe-incorporated Ni_(3)S_(2)nanosheets in-situ grown on Ni foam(Fe-Ni_(3)S_(2)@NF)was fabricated by a facile two-step hydrothermal process and applied to trigger peroxymonosulfate(PMS)oxidation of organic compounds inwater.A homogeneous growth environment enabled the uniform and scalable growth of Fe-Ni_(3)S_(2)nanosheets on the Ni foam.Fe-Ni_(3)S_(2)@NF possessed outstanding activity and durability in activating PMS,as it effectively facilitated electron transfer from organic pollutants to PMS.Fe-Ni_(3)S_(2)@NF initially supplied electrons to PMS,causing the catalyst to undergo oxidation,and subsequently accepted electrons from organic compounds,returning to its initial state.The introduction of Fe into the Ni_(3)S_(2)lattice enhanced electrical conductivity,promoting mediated electron transfer between PMS and organic compounds.The 3D conductive Ni foam provided an ideal platform for the nucleation and growth of Fe-Ni_(3)S_(2),accelerating pollutant abatement due to its porous structure and high conductivity.Furthermore,its monolithic nature simplified the catalyst recycling process.A continuous flow packed-bed reactor by encapsulating Fe-Ni_(3)S_(2)@NF catalyst achieved complete pollutant abatement with continuous operation for 240 h,highlighting its immense potential for practical environmental remediation.This study presents a facile synthesis method for creating a novel type of monolithic catalyst with high activity and durability for decontamination through Fenton-like processes.
基金financially supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK1003)the Science and Technology Innovation Pro-gram of Hunan Province(No.2022RC1122)。
文摘Layered double hydroxide(LDH)based heterogonous peroxymonosulfate(PMS)activation degradation of pollutants has attracted extensive attention.The challenge is to selectively regulate the traditional free radical dominant degradation pathway into a nonradical degradation pathway.Herein,an interface ar-chitecture of Ti_(3) C_(2) T_(x)-MXene(MXene)loading on the Fe-Al LDH scaffold was developed,which showed excellent stability and robust resistance against harsh conditions.Significantly,the rate constant for tetra-cycline hydrochloride(TC)degradation in the MXene-LDH/PMS process was 0.421 min^(-1),which was ten times faster than the rate constant for pure Fe-Al LDH(0.042 min^(-1)).Specifically,more reactive Fe with the closer d-band center to the Fermi level results in higher electron transfer efficiency.The occupa-tions of Fe-3d orbitals in Mxene/Fe-Al LDH are pushed above the Fermi level to generate,which results in higher PMS adsorption and inhibition of the release of oxygen-containing active species intermedi-ates,leading to the enhanced^(1)O_(2) generation.Additionally,the built-in electric field in the heterojunc-tion was driven by the charge redistribution between MXene and Fe-Al LDH,resulting in a mediated-electron transfer mechanism,differentiating it from the Fe-Al LDH/PMS system.It was fascinating that MXene/Fe-Al LDH achieved satisfactory treatment efficiency in continuous column reactor and real landfill leachate.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3009400)the National Natural Science Foundation of China(Grant Nos.42307218 and U2239251).
文摘The current deep learning models for braced excavation cannot predict deformation from the beginning of excavation due to the need for a substantial corpus of sufficient historical data for training purposes.To address this issue,this study proposes a transfer learning model based on a sequence-to-sequence twodimensional(2D)convolutional long short-term memory neural network(S2SCL2D).The model can use the existing data from other adjacent similar excavations to achieve wall deflection prediction once a limited amount of monitoring data from the target excavation has been recorded.In the absence of adjacent excavation data,numerical simulation data from the target project can be employed instead.A weight update strategy is proposed to improve the prediction accuracy by integrating the stochastic gradient masking with an early stopping mechanism.To illustrate the proposed methodology,an excavation project in Hangzhou,China is adopted.The proposed deep transfer learning model,which uses either adjacent excavation data or numerical simulation data as the source domain,shows a significant improvement in performance when compared to the non-transfer learning model.Using the simulation data from the target project even leads to better prediction performance than using the actual monitoring data from other adjacent excavations.The results demonstrate that the proposed model can reasonably predict the deformation with limited data from the target project.
文摘在智能反射面(Intelligent Reflective Surface,IRS)辅助的多天线车联网中,性能增益通常是在天线硬件完善的情况下实现,但实际的天线硬件缺陷可能会降低这些增益。在考虑天线硬件损伤的情况下,针对IRS辅助的多输入单输出(Multiple-Input Single-Output,MISO)下行车联网无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)系统,提出了一种主动式和被动式联合的波束赋形设计方法。在信干噪比、最小接收能量阈值、IRS相移等约束条件下,以最小化基站发射总功率为目标,运用半定松弛(Semidefinite Relaxation,SDR)、矩阵分析理论等方法,将具有耦合变量的非凸优化问题转化成解耦后的凸优化问题,并用交替迭代优化算法来求得原问题的解。仿真结果表明,在车联网SWIPT系统中考虑硬件损伤的必要性和IRS辅助的有效性,并给出了算法的收敛性和车速、IRS反射单元数等系统参数对系统性能的影响。
文摘In radiology,magnetic resonance imaging(MRI)is an essential diagnostic tool that provides detailed images of a patient’s anatomical and physiological structures.MRI is particularly effective for detecting soft tissue anomalies.Traditionally,radiologists manually interpret these images,which can be labor-intensive and time-consuming due to the vast amount of data.To address this challenge,machine learning,and deep learning approaches can be utilized to improve the accuracy and efficiency of anomaly detection in MRI scans.This manuscript presents the use of the Deep AlexNet50 model for MRI classification with discriminative learning methods.There are three stages for learning;in the first stage,the whole dataset is used to learn the features.In the second stage,some layers of AlexNet50 are frozen with an augmented dataset,and in the third stage,AlexNet50 with an augmented dataset with the augmented dataset.This method used three publicly available MRI classification datasets:Harvard whole brain atlas(HWBA-dataset),the School of Biomedical Engineering of Southern Medical University(SMU-dataset),and The National Institute of Neuroscience and Hospitals brain MRI dataset(NINS-dataset)for analysis.Various hyperparameter optimizers like Adam,stochastic gradient descent(SGD),Root mean square propagation(RMS prop),Adamax,and AdamW have been used to compare the performance of the learning process.HWBA-dataset registers maximum classification performance.We evaluated the performance of the proposed classification model using several quantitative metrics,achieving an average accuracy of 98%.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3900400)the National Natural Science Foundation of China(Grant Nos.U2142212 and 42361074)。
文摘Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BZ2022007)the National Natural Science Foundation of China(No.92261202)+1 种基金the Ministry of Science and Technology of the People’s Republic of China(No.2021YFE0114800)the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2021-1027).
文摘Thermally activated delayed fluorescence(TADF)materials driven by a through-space charge transfer(TSCT)mechanism have garnered wide interest.However,access of TSCT-TADF molecules with longwavelength emission remains a formidable challenge.In this study,we introduce a novel V-type DA-D-A’emitter,Trz-mCzCbCz,by using a carborane scaffold.This design strategically incorporates carbazole(Cz)and 2,4,6-triphenyl-1,3,5-triazine(Trz)as donor and acceptor moieties,respectively.Theoretical calculations alongside experimental validations affirm the typical TSCT-TADF characteristics of this luminogen.Owing to the unique structural and electronic attributes of carboranes,Trz-mCzCbCz exhibits an orange-red emission,markedly diverging from the traditional blue-to-green emissions observed in classical Cz and Trz-based TADF molecules.Moreover,bright emission in aggregates was observed for Trz-mCzCbCz with absolute photoluminescence quantum yield(PLQY)of up to 88.8%.As such,we have successfully fabricated five organic light-emitting diodes(OLEDs)by utilizing Trz-mCzCbCz as the emitting layer.It is important to note that both the reverse intersystem crossing process and the TADF properties are profoundly influenced by host materials.The fabricated OLED devices reached a maximum external quantum efficiency(EQE)of 12.7%,with an emission peak at 592 nm.This represents the highest recorded efficiency for TSCT-TADF OLEDs employing carborane derivatives as emitting layers.
基金Industry Foresight and Key Core Technology(No.YZ2023019)Cooperation Project of Yangzhou City with Yangzhou University(No.YZ2023209)+3 种基金Sichuan Tianfu Talent Programme(No.A.2200732)Chengdu Rongpiao Talent Programme(No.1043)SeleValley Scholars Basic Research Project(No.2301)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)for financial support。
文摘Element Transfer Reaction(ETR)theory is a new fundamental theory guiding the design of synthetic routes.It analyses problems from a brand-new perspective of element circulation,decomposing the factors affecting synthetic efficiency into three elements:element sources,driving force,and output.Different from the retrosynthetic analysis method and the atom economy theory,the ETR theory places more emphasis on examining the problem as a whole and comprehensively considering various factors involved in industrial applications.This perspective intends to elaborate on the scientific connotation of the ETR theory and explore its characteristics by discussing the practical application cases.
文摘Photocatalytic hydrogen production technology is an ideal approach to addressing energy and environmental issues,with efficient charge transfer being the key to achieving high-performance hydrogen production.Ultra-thin CuInS_(2)nanosheets were prepared through a solvothermal method.Subsequently,metallic Ni was surface-modified onto CuInS_(2)through photo-deposition to serve as a co-catalyst.The optimized photocatalyst exhibited a hydrogen production rate of 15.5 mmol·g^(-1)·h^(-1)in water when used an ascorbic acid as hole scavenger,which is 9 times that of the original CuInS_(2).Transient absorption spectra(TAS)analysis demonstrates that the hole transfer from CuInS_(2)nanosheets to ascorbic acid,yielding a long-lived electron with a lifetime of 45.6μs.The electrons in CuInS_(2)are efficiently captured by Ni as active sites for driving hydrogen evolution.In situ TAS further indicates that ascorbic acid and Ni sites synergistically promote the electron transfer dynamics of CuInS_(2),achieving an electron transfer efficiency of 48.4%.This work provides a viable strategy for designing highly efficient photocatalysts with enhanced charge transfer.
基金supported by grants from the National Natural Science Foundation of China(NSFC Nos.51972347 and 21771195).
文摘Inorganic lead-free double perovskites have the advantages of low toxicity,broadband emission,and good stability,which make them promising luminescent materials for lighting applications.However,due to the limited regulation of their self-trapped exciton emission,it is still greatly challenging to achieve white light emitting from a single double perovskite host.Herein,efficient and tunable white light is realized in Cs_(2)NalnCl_(6)∶Sb^(3+),Tb^(3+),Sm^(3+)double perovskite by controlling the ratios of the doped three ions with blue,green,and red emissions,respectively.The steady-state and transient fluorescence spectra of singly-and doubly-doped double perovskites reveal the existence of multiple energy transfer channels in the triply-doped phosphors,including from Sb^(3+)to Tb^(3+),Sb^(3+)to Sm^(3+),and Tb^(3+)to Sm^(3+).Benefiting from these channels,the color coordinates of the triply-doped phosphors can cross the whole white light area of the CIE chromaticity diagram by adjusting the ratios of the three dopants,and the maximum internal quantum yield of the white light phosphors is 66.61%.The white emission phosphors show the characteristic of being independent of excitation wavelength within 310-360 nm.Furthermore,the emission intensity at 430 K of the white light phosphor Cs_(2)NalnCl_(6)∶0.01Sb^(3+),0.65Tb^(3+),0.20Sm^(3+)remains 50% of that at room temperature.A WLED device fabricated with the phosphor and a 365 nm LED chip exhibits a high color rendering index of 90.9,correlated color temperature of 5469 K,and CIE coordinates of(0.333 and 0.328).The results indicate that the as-prepared double perovskite materials are promising candidates in the solid-state lighting field.
