Nuclear astrophysics is a rapidly developing interdisciplinary feld of research that has received extensive attention from the scientifc community since the midtwentieth century.Broadly,it uses the laws of extremely s...Nuclear astrophysics is a rapidly developing interdisciplinary feld of research that has received extensive attention from the scientifc community since the midtwentieth century.Broadly,it uses the laws of extremely small atomic nuclei to explain the evolution of the universe.Owing to the complexity of nucleosynthesis processes and our limited understanding of nuclear physics in astrophysical environments,several critical astrophysical problems remain unsolved.To achieve a better understanding of astrophysics,it is necessary to measure the cross sections of key nuclear reactions with the precision required by astrophysical models.Direct measurement of nuclear reaction cross sections is an important method of investigating how nuclear reactions infuence stellar evolution.Given the challenges involved in measuring the extremely low crosssections of nuclear reactions in the Gamow peak and preparing radioactive targets,indirect methods,such as the transfer reaction,coulomb dissociation,and surrogate ratio methods,have been developed over the past several decades.These are powerful tools in the investigation of,for example,neutron-capture(n,r)reactions with short-lived radioactive isotopes.However,direct measurement is still preferable,such as in the case of reactions involving light and stable nuclei.As an essential part of stellar evolution,these low-energy stable nuclear reactions have been of particular interest in recent years.To overcome the diffculties in measurements near or deeply within the Gamow window,the combination of an underground laboratory and high-exposure accelerator/detector complex is currently the optimal solution.Therefore,underground experiments have emerged as a new and promising direction of research.In addition,to better simulate the stellar environment in the laboratory,research on nuclear physics under laser-driven plasma conditions has gradually become a frontier hotspot.In recent years,the CIAE team conducted a series of distinctive nuclear astrophysics studies,relying on the Jinping Underground Nuclear Astrophysics platform and accelerators in Earth’s surface laboratories,including the Beijing Radioactive Ion beam Facility,as well as other scientifc platforms at home and abroad.This research covered nuclear theories,numerical models,direct measurements,indirect measurements,and other novel approaches,achieving great interdisciplinary research results,with high-level academic publications and signifcant international impacts.This article reviews the above research and predicts future developments.展开更多
Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research.It aims to unravel the intricate processes involving the excitations,interact...Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research.It aims to unravel the intricate processes involving the excitations,interactions,and annihilations of quasi-and many-body particles,and ultimately to achieve the manipulation and engineering of exotic non-equilibrium quantum phases on the ultrasmall and ultrafast spatiotemporal scales.Given the inherent complexities arising from many-body dynamics,it therefore seeks a technique that has efficient and diverse detection degrees of freedom to study the underlying physics.By combining high-power femtosecond lasers with real-or momentum-space photoemission electron microscopy(PEEM),imaging excited state phenomena from multiple perspectives,including time,real space,energy,momentum,and spin,can be conveniently achieved,making it a unique technique in studying physics out of equilibrium.In this context,we overview the working principle and technical advances of the PEEM apparatus and the related laser systems,and survey key excited-state phenomena probed through this surface-sensitive methodology,including the ultrafast dynamics of electrons,excitons,plasmons,spins,etc.,in materials ranging from bulk and nano-structured metals and semiconductors to low-dimensional quantum materials.Through this review,one can further envision that time-resolved PEEM will open new avenues for investigating a variety of classical and quantum phenomena in a multidimensional parameter space,offering unprecedented and comprehensive insights into important questions in the field of condensed matter physics.展开更多
By using the standard PMNS (Pontecorvo-Maki-Nakagawa-Sakata) mixing matrix and applying the rule for the sum of the oscillation probabilities of three neutrinos, the equations of motion were derived in which the Dirac...By using the standard PMNS (Pontecorvo-Maki-Nakagawa-Sakata) mixing matrix and applying the rule for the sum of the oscillation probabilities of three neutrinos, the equations of motion were derived in which the Dirac CP violating phase appeared as an unknown quantity. The equations of motion were separately derived for each of the three possible transitions for flavor-neutrino oscillations. Two roots of those equations were obtained in the form of two formulas for the Dirac CP violating phase with opposite signs. In the mathematical sense, the connection between those formulas was established in order to maintain the continuous process of oscillation of three neutrinos. This made it possible to calculate the numerical value for the Dirac CP violating phase, the Jarlskog invariant and to write the general form of the PMNS mixing matrix in the final form in which all its elements are defined with explicit numerical values.展开更多
We identify an S-shaped main-jet axis in the Vela core-collapse supernova remnant(CCSNR)that we attribute to a pair of precessing jets,one of the tens of pairs of jets that exploded the progenitor of Vela according to...We identify an S-shaped main-jet axis in the Vela core-collapse supernova remnant(CCSNR)that we attribute to a pair of precessing jets,one of the tens of pairs of jets that exploded the progenitor of Vela according to the jittering jets explosion mechanism(JJEM).A main-jet axis is a symmetry axis across the CCSNR and through the center.We identify the S-shaped main-jet axis by the high abundance of ejecta elements,oxygen,neon,and magnesium.We bring the number of identified pairs of clumps and ears in Vela to seven,two pairs shaped by the pair of precessing jets that formed the main-jet axis.The pairs and the main-jet axis form the point-symmetric wind-rose structure of Vela.The other five pairs of clumps/ears do not have signatures near the center,only on two opposite sides of the CCSNR.We discuss different possible jet-less shaping mechanisms to form such a point-symmetric morphology and dismiss these processes because they cannot explain the point-symmetric morphology of Vela,the S-shaped high ejecta abundance pattern,and the enormous energy required to shape the S-shaped structure.Our findings strongly support the JJEM and further severely challenge the neutrino-driven explosion mechanism.展开更多
With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unk...With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unknown.Therefore,by studying the formation and orbital transformation mechanism of satellites,planets and stars,the author puts forward a new theory on the formation and evolution of stars and galaxies,thus revealing the hierarchical structure of galaxies and the formation and evolution laws of main sequence stars,red giants,white dwarfs,black dwarfs,supernovae,neutron stars,black holes and quasars.Some special phenomena in the course of star formation and evolution,such as sunspots,flares,fast radio bursts and gamma-ray bursts,have also been revealed.展开更多
Depolarizing behavior is commonly observed in most natural samples.For this reason,optical tools measuring the differences in depolarization response among spatially separated structures are highly useful in a wide ra...Depolarizing behavior is commonly observed in most natural samples.For this reason,optical tools measuring the differences in depolarization response among spatially separated structures are highly useful in a wide range of imaging applications for enhanced visualization of structures,target identification,etc.One commonly used tool for depolarizing discrimination is the so-called depolarizing spaces.In this article,we exploit the combined use of two depolarizing spaces,the indices of polarization purity(IPP)and polarizance–reflection–transformation(PRT)spaces,to improve the capability of optical systems to identify polarization–anisotropy depolarizers.The potential of these spaces to discriminate among different depolarizers is first studied from a series of simulations by incoherently adding diattenuations or retarders,with some control parameters emulating samples in nature.The simulated results demonstrate that the proposed methods are capable of increasing differences among depolarizers beyond other well-known techniques.Experimentally,validation is provided by conducting diverse phantom experiments of easy interpretation and mimicking the stated simulations.As a useful application of our approach,we developed a model able to retrieve intrinsic microscopic information of samples from macroscopic polarimetric measurements.The proposed methods enable non-invasive,straightforward,macroscopic characterization of depolarizing samples,and may be of interest for enhanced visualization of samples in multiple imaging scenarios.展开更多
The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious int...The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious interfacial instability,which is a big challenge for design and application of nonflammable GPEs.Here,a nonflammable GPE(SGPE)is developed by in situ polymerizing trifluoroethyl methacrylate(TFMA)monomers with flame-retardant triethyl phosphate(TEP)solvents and LiTFSI–LiDFOB dual lithium salts.TEP is strongly anchored to PTFMA matrix via polarity interaction between-P=O and-CH_(2)CF_(3).It reduces free TEP molecules,which obviously mitigates interfacial reactions,and enhances flame-retardant performance of TEP surprisingly.Anchored TEP molecules are also inhibited in solvation of Li^(+),leading to anion-dominated solvation sheath,which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers.Such coordination structure changes Li^(+)transport from sluggish vehicular to fast structural transport,raising ionic conductivity to 1.03 mS cm^(-1) and transfer number to 0.41 at 30℃.The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm^(−2),and 4.2 V LiCoO_(2)|SGPE|Li battery delivers high average specific capacity>120 mAh g^(−1) over 200 cycles.This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.展开更多
Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and ...Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.展开更多
Two existing solutions for the diffusion of cosmic rays (CRs) are analyzed. The first one is a well-known solution in 3D over an infinite spatial domain and the second one is a 1D solution with an exponential decay in...Two existing solutions for the diffusion of cosmic rays (CRs) are analyzed. The first one is a well-known solution in 3D over an infinite spatial domain and the second one is a 1D solution with an exponential decay initial profile over an infinite spatial domain. For each solution, the temporal evolution of the number of particles at a fixed distance has been analyzed. The anticorrelation between the flux of CRs and the magnetic field at one astronomical unit has been explained by adopting a careful choice of the astrophysical parameters involved.展开更多
One dimensional sub-wavelength gratings,also known as metagratings have attracted enormous attention due to the relatively simpler design configurations with versatile application potentials.In recent times,these meta...One dimensional sub-wavelength gratings,also known as metagratings have attracted enormous attention due to the relatively simpler design configurations with versatile application potentials.In recent times,these metagratings have played crucial roles in terahertz frequency domain to realize several fascinating effects.It has been demonstrated that the terahertz characteristics of these metagratings can be modified by carefully designing the grating geometry along with meticulously tuning the material characteristics.Such variations in grating design have led to enhanced device performances.In addition,suitably designed metagratings are capable of exciting strong evanescent orders that can be exploited in ultrasensitive sensing,optical trapping,non-linearity,etc.Based on the tremendous potentials offered by the planar geometry(ease of fabrication)along with diverse utilities,we have reviewed few representative works pertaining to terahertz metagratings in this article.Hence,we have discussed metagratings based antireflection coating and a polarization beam splitter operating in THz region modelled using simplified model method.Further,we have discussed experimental detection of evanescent waves excited in metagratings utilizing Fourier transformed terahertz spectroscopy(FTTS)technique.FTTS is a unique technique because of its ability of simultaneous detection of propagating and non-propagating orders.Next,we have discussed applications of metagratings in sensing trace amount of analytes.Considering the increasing interests in these one-dimensional artificial subwavelength structures,we believe,our article will be useful for the researchers willing to begin work on terahertz subwavelength gratings.展开更多
Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simul...Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simultaneously control the growth of perovskite crystals and passivate defects.Here,4-(trifluoromethyl)benzoic anhydride(4-TBA)composed of benzene rings functionalized with carbonyl and trifluoromethyl groups was used as an example additive to study the characteristics of additives used for producing high-quality perovskites and controlling their surface properties.The interaction between4-TBA and perovskite precursor materials was investigated using density functional theory(DFT)simulations.The electron-rich carbonyl group efficiently passivated the under-coordinated lead-ion defects.Additionally,hydrogen bonding between trifluoromethyl and organic cations prevents the generation of cation vacancies.Because of its intrinsic hydrophobicity,the trifluoromethyl group simultaneously improves the moisture and heat stability of the film.4-TBA serves as a universal modifier for various perovskite compositions.The power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs)based on methylammonium(MA)with 4-TBA was improved from 16.15%to 19.28%.Similarly,the PCE of inverted PSCs based on a cesium formamidinium MA(CsFAMA)perovskite film increased from20.72%to 23.58%,upon addition of 4-TBA.Furthermore,the moisture and thermal stability of 4-TBAtreated films and devices was significantly enhanced,along with prolonged device performance.Our work provides guidance on selecting the structure and functional groups that are essential for surface defect passivation and the production of high-quality perovskites.展开更多
Metal nanoparticles with high surface area and high electrochemical activity exhibit excellent catalytic performance in the photocatalytic reduction of carbon dioxide(CO_(2)).However,poor stability,small specific surf...Metal nanoparticles with high surface area and high electrochemical activity exhibit excellent catalytic performance in the photocatalytic reduction of carbon dioxide(CO_(2)).However,poor stability,small specific surface area,and less active sites limits its solar energy utilization.Hydrothermal method was utilized to synthesize the bimetallic material of Cu_(x)Co_(1-x)in this work.Co was loaded onto the Cu surface due to the electrons generated by the surface plasmon resonance(SPR)effect occurring on the Cu surface.Cu_(x)Co_(1-x)exhibits high photocatalytic conversion of CO_(2)efficiency under irradiation,which mainly because the Co nanoparticles on the surface of Cu can be used as cocatalysts to enhance the photocharge transfer.Cu_(0.6)Co_(0.4)exhibits the comparatively best photocatalytic conversion efficiency of CO_(2)in the first 6 h light irradiation.The yields of CO and CH_(4)reached 35.26 and 2.71μmol/(g·h),respectively.Upon illumination,electrons were produced,with the majority of them moving towards the interface.This movement contributes to the increased lifetime of photogenerated electron-hole pairs,which in turn boosts the photocatalytic efficiency.The findings of this research provide significant insights for creating photocatalysts that are both highly effective and stable in CO_(2)reduction processes.展开更多
The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of t...The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of the sediments.Major oxides,trace elements,and rare earth elements(REEs)obtained from the INAA technique are presented by analyzing the sediment samples collected from the shoreline of St.Martin’s Island,Bangladesh.The elemental ratios,comparison with average upper continental crust(UCC),binary diagrams(Th/Sc vs.Sc,La/Th vs.Hf,Th/Co vs.La/Sc),and chondrite normalized REE patterns exhibit substantial LREE enrichment,relatively fl at HREE fractionation,considerable negative Eu anomalies(average:0.72),indicates the derivation from a source dominated by felsic rock,with contribution from intermediate source and mafi c component.Sediments from St.Martin’s Island exhibit the deposition of sediments in transitional environments of active and passive continental margin settings.Weathering indices value of CIA,PIA,CIW,CIX,and K 2 O/Rb ratio show moderate chemical weathering,indicating that the sediments are chemically mature.Sedimentary redox indicative proxies,such as U/Th,V/Cr,and V/Sc,show an oxic depositional environment during sediment deposition.The intermediate CIA and other weathering index values of the St.Martin’s sediments show that the area had semiarid and humid climatic conditions throughout the deposition.The Rb/K ratio of the St.Martin’s sediments suggests that the development and deposition of the sedimentary sequence of St.Martin’s Island mainly occurred in a brackish water environment during the geological past.展开更多
The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs b...The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.展开更多
Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy wi...Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.展开更多
Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and...Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.展开更多
We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monito...We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.展开更多
The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical lin...The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical line with its length indicating the bandwidth(70-130 kHz).The horizontal error bars signify the end time uncertainty.The vertical dashed line marks the SGRE end(06:28 UT,September 7);the horizontal dashed line represents the gamma-ray background.The shock arrival time at 1 au is labeled“SH”(Gopalswamy et al.2018).展开更多
基金National Natural Science Foundation of China(Nos.12435010)National Key R&D Program of China(No.2022YFA1602301)。
文摘Nuclear astrophysics is a rapidly developing interdisciplinary feld of research that has received extensive attention from the scientifc community since the midtwentieth century.Broadly,it uses the laws of extremely small atomic nuclei to explain the evolution of the universe.Owing to the complexity of nucleosynthesis processes and our limited understanding of nuclear physics in astrophysical environments,several critical astrophysical problems remain unsolved.To achieve a better understanding of astrophysics,it is necessary to measure the cross sections of key nuclear reactions with the precision required by astrophysical models.Direct measurement of nuclear reaction cross sections is an important method of investigating how nuclear reactions infuence stellar evolution.Given the challenges involved in measuring the extremely low crosssections of nuclear reactions in the Gamow peak and preparing radioactive targets,indirect methods,such as the transfer reaction,coulomb dissociation,and surrogate ratio methods,have been developed over the past several decades.These are powerful tools in the investigation of,for example,neutron-capture(n,r)reactions with short-lived radioactive isotopes.However,direct measurement is still preferable,such as in the case of reactions involving light and stable nuclei.As an essential part of stellar evolution,these low-energy stable nuclear reactions have been of particular interest in recent years.To overcome the diffculties in measurements near or deeply within the Gamow window,the combination of an underground laboratory and high-exposure accelerator/detector complex is currently the optimal solution.Therefore,underground experiments have emerged as a new and promising direction of research.In addition,to better simulate the stellar environment in the laboratory,research on nuclear physics under laser-driven plasma conditions has gradually become a frontier hotspot.In recent years,the CIAE team conducted a series of distinctive nuclear astrophysics studies,relying on the Jinping Underground Nuclear Astrophysics platform and accelerators in Earth’s surface laboratories,including the Beijing Radioactive Ion beam Facility,as well as other scientifc platforms at home and abroad.This research covered nuclear theories,numerical models,direct measurements,indirect measurements,and other novel approaches,achieving great interdisciplinary research results,with high-level academic publications and signifcant international impacts.This article reviews the above research and predicts future developments.
基金Project supported by the National Natural Science Foundation of China(Grant No.12374223)Shenzhen Science and Technology Program(Grant No.20231117151322001).
文摘Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research.It aims to unravel the intricate processes involving the excitations,interactions,and annihilations of quasi-and many-body particles,and ultimately to achieve the manipulation and engineering of exotic non-equilibrium quantum phases on the ultrasmall and ultrafast spatiotemporal scales.Given the inherent complexities arising from many-body dynamics,it therefore seeks a technique that has efficient and diverse detection degrees of freedom to study the underlying physics.By combining high-power femtosecond lasers with real-or momentum-space photoemission electron microscopy(PEEM),imaging excited state phenomena from multiple perspectives,including time,real space,energy,momentum,and spin,can be conveniently achieved,making it a unique technique in studying physics out of equilibrium.In this context,we overview the working principle and technical advances of the PEEM apparatus and the related laser systems,and survey key excited-state phenomena probed through this surface-sensitive methodology,including the ultrafast dynamics of electrons,excitons,plasmons,spins,etc.,in materials ranging from bulk and nano-structured metals and semiconductors to low-dimensional quantum materials.Through this review,one can further envision that time-resolved PEEM will open new avenues for investigating a variety of classical and quantum phenomena in a multidimensional parameter space,offering unprecedented and comprehensive insights into important questions in the field of condensed matter physics.
文摘By using the standard PMNS (Pontecorvo-Maki-Nakagawa-Sakata) mixing matrix and applying the rule for the sum of the oscillation probabilities of three neutrinos, the equations of motion were derived in which the Dirac CP violating phase appeared as an unknown quantity. The equations of motion were separately derived for each of the three possible transitions for flavor-neutrino oscillations. Two roots of those equations were obtained in the form of two formulas for the Dirac CP violating phase with opposite signs. In the mathematical sense, the connection between those formulas was established in order to maintain the continuous process of oscillation of three neutrinos. This made it possible to calculate the numerical value for the Dirac CP violating phase, the Jarlskog invariant and to write the general form of the PMNS mixing matrix in the final form in which all its elements are defined with explicit numerical values.
基金A grant from the Pazy Foundation supported this research
文摘We identify an S-shaped main-jet axis in the Vela core-collapse supernova remnant(CCSNR)that we attribute to a pair of precessing jets,one of the tens of pairs of jets that exploded the progenitor of Vela according to the jittering jets explosion mechanism(JJEM).A main-jet axis is a symmetry axis across the CCSNR and through the center.We identify the S-shaped main-jet axis by the high abundance of ejecta elements,oxygen,neon,and magnesium.We bring the number of identified pairs of clumps and ears in Vela to seven,two pairs shaped by the pair of precessing jets that formed the main-jet axis.The pairs and the main-jet axis form the point-symmetric wind-rose structure of Vela.The other five pairs of clumps/ears do not have signatures near the center,only on two opposite sides of the CCSNR.We discuss different possible jet-less shaping mechanisms to form such a point-symmetric morphology and dismiss these processes because they cannot explain the point-symmetric morphology of Vela,the S-shaped high ejecta abundance pattern,and the enormous energy required to shape the S-shaped structure.Our findings strongly support the JJEM and further severely challenge the neutrino-driven explosion mechanism.
文摘With the advancement of astronomical observation technology,people have a deeper understanding of the formation and evolution of galaxies,but many details of our own Milky Way and other external galaxies are still unknown.Therefore,by studying the formation and orbital transformation mechanism of satellites,planets and stars,the author puts forward a new theory on the formation and evolution of stars and galaxies,thus revealing the hierarchical structure of galaxies and the formation and evolution laws of main sequence stars,red giants,white dwarfs,black dwarfs,supernovae,neutron stars,black holes and quasars.Some special phenomena in the course of star formation and evolution,such as sunspots,flares,fast radio bursts and gamma-ray bursts,have also been revealed.
基金supported by the China Scholarship Council(Grant No.202306690024)the Ministerio de Ciencia e Innovación and Fondos FEDER(Grant Nos.PID2021-562126509OB-C21 and PDC2022-133332-C21)+1 种基金the Generalitat de Catalunya(Grant No.2021SGR00138)the Beatriu de Pinós Fellowship(Grant No.2021-BP-00206).
文摘Depolarizing behavior is commonly observed in most natural samples.For this reason,optical tools measuring the differences in depolarization response among spatially separated structures are highly useful in a wide range of imaging applications for enhanced visualization of structures,target identification,etc.One commonly used tool for depolarizing discrimination is the so-called depolarizing spaces.In this article,we exploit the combined use of two depolarizing spaces,the indices of polarization purity(IPP)and polarizance–reflection–transformation(PRT)spaces,to improve the capability of optical systems to identify polarization–anisotropy depolarizers.The potential of these spaces to discriminate among different depolarizers is first studied from a series of simulations by incoherently adding diattenuations or retarders,with some control parameters emulating samples in nature.The simulated results demonstrate that the proposed methods are capable of increasing differences among depolarizers beyond other well-known techniques.Experimentally,validation is provided by conducting diverse phantom experiments of easy interpretation and mimicking the stated simulations.As a useful application of our approach,we developed a model able to retrieve intrinsic microscopic information of samples from macroscopic polarimetric measurements.The proposed methods enable non-invasive,straightforward,macroscopic characterization of depolarizing samples,and may be of interest for enhanced visualization of samples in multiple imaging scenarios.
基金supported by the National Natural Science Foundation of China(Nos.52172214,52272221,52171182)the Postdoctoral Innovation Project of Shandong Province(No.202102003)+2 种基金The Key Research and Development Program of Shandong Province(2021ZLGX01)the Qilu Young Scholar ProgramHPC Cloud Platform of Shandong University are also thanked.
文摘The risk of flammability is an unavoidable issue for gel polymer electrolytes(GPEs).Usually,flameretardant solvents are necessary to be used,but most of them would react with anode/cathode easily and cause serious interfacial instability,which is a big challenge for design and application of nonflammable GPEs.Here,a nonflammable GPE(SGPE)is developed by in situ polymerizing trifluoroethyl methacrylate(TFMA)monomers with flame-retardant triethyl phosphate(TEP)solvents and LiTFSI–LiDFOB dual lithium salts.TEP is strongly anchored to PTFMA matrix via polarity interaction between-P=O and-CH_(2)CF_(3).It reduces free TEP molecules,which obviously mitigates interfacial reactions,and enhances flame-retardant performance of TEP surprisingly.Anchored TEP molecules are also inhibited in solvation of Li^(+),leading to anion-dominated solvation sheath,which creates inorganic-rich solid electrolyte interface/cathode electrolyte interface layers.Such coordination structure changes Li^(+)transport from sluggish vehicular to fast structural transport,raising ionic conductivity to 1.03 mS cm^(-1) and transfer number to 0.41 at 30℃.The Li|SGPE|Li cell presents highly reversible Li stripping/plating performance for over 1000 h at 0.1 mA cm^(−2),and 4.2 V LiCoO_(2)|SGPE|Li battery delivers high average specific capacity>120 mAh g^(−1) over 200 cycles.This study paves a new way to make nonflammable GPE that is compatible with Li metal anode.
基金Suranaree University of Technology(SUT)Thailand Science,Research and Innovation(TSRI)National Science,Research and Innovation Fund(NSRF)(project cord.179314)。
文摘Delafossite AgFeO_(2)nanoparticles with a mixture of 2H and 3R phases were successfully fabricated by using a simple co-precipitation method.The resulting precursor was calcined at temperatures of 100,200,300,400,and 500℃to obtain the delafossite AgFe0_(2)phase.The morphology and microstructure of the prepared AgFeO_(2)samples were characterized by using field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM),N_(2) adsorption/desorption,X-ray absorption spectroscopy(XAS),and Xray photoelectron spectroscopy(XPS)techniques.A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO_(2)nanoparticles in a 3 M KOH electrolyte.The delafossite AgFeO_(2)nanoparticles calcined at 100℃(AFO100)exhibited the highest surface area of 28.02 m^(2)·g^(-1)and outstanding electrochemical performance with specific capacitances of 229.71 F·g^(-1)at a current density of 1 A·g^(-1)and 358.32 F·g^(-1)at a scan rate of 2 mV·s^(-1).This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles,along with superior specific power and specific energy values of 797.46 W·kg^(-1)and 72.74Wh·kg^(-1),respectively.These findings indicate that delafossite AgFeO_(2)has great potential as an electrode material for supercapacitor applications.
文摘Two existing solutions for the diffusion of cosmic rays (CRs) are analyzed. The first one is a well-known solution in 3D over an infinite spatial domain and the second one is a 1D solution with an exponential decay initial profile over an infinite spatial domain. For each solution, the temporal evolution of the number of particles at a fixed distance has been analyzed. The anticorrelation between the flux of CRs and the magnetic field at one astronomical unit has been explained by adopting a careful choice of the astrophysical parameters involved.
文摘One dimensional sub-wavelength gratings,also known as metagratings have attracted enormous attention due to the relatively simpler design configurations with versatile application potentials.In recent times,these metagratings have played crucial roles in terahertz frequency domain to realize several fascinating effects.It has been demonstrated that the terahertz characteristics of these metagratings can be modified by carefully designing the grating geometry along with meticulously tuning the material characteristics.Such variations in grating design have led to enhanced device performances.In addition,suitably designed metagratings are capable of exciting strong evanescent orders that can be exploited in ultrasensitive sensing,optical trapping,non-linearity,etc.Based on the tremendous potentials offered by the planar geometry(ease of fabrication)along with diverse utilities,we have reviewed few representative works pertaining to terahertz metagratings in this article.Hence,we have discussed metagratings based antireflection coating and a polarization beam splitter operating in THz region modelled using simplified model method.Further,we have discussed experimental detection of evanescent waves excited in metagratings utilizing Fourier transformed terahertz spectroscopy(FTTS)technique.FTTS is a unique technique because of its ability of simultaneous detection of propagating and non-propagating orders.Next,we have discussed applications of metagratings in sensing trace amount of analytes.Considering the increasing interests in these one-dimensional artificial subwavelength structures,we believe,our article will be useful for the researchers willing to begin work on terahertz subwavelength gratings.
基金supported by a Research Grant of Pukyong National University(2023)。
文摘Achieving high-quality perovskite films without surface defects is regarded as a crucial target for the development of durable high-performance perovskite solar cells.Additive engineering is commonly employed to simultaneously control the growth of perovskite crystals and passivate defects.Here,4-(trifluoromethyl)benzoic anhydride(4-TBA)composed of benzene rings functionalized with carbonyl and trifluoromethyl groups was used as an example additive to study the characteristics of additives used for producing high-quality perovskites and controlling their surface properties.The interaction between4-TBA and perovskite precursor materials was investigated using density functional theory(DFT)simulations.The electron-rich carbonyl group efficiently passivated the under-coordinated lead-ion defects.Additionally,hydrogen bonding between trifluoromethyl and organic cations prevents the generation of cation vacancies.Because of its intrinsic hydrophobicity,the trifluoromethyl group simultaneously improves the moisture and heat stability of the film.4-TBA serves as a universal modifier for various perovskite compositions.The power conversion efficiency(PCE)of inverted perovskite solar cells(PSCs)based on methylammonium(MA)with 4-TBA was improved from 16.15%to 19.28%.Similarly,the PCE of inverted PSCs based on a cesium formamidinium MA(CsFAMA)perovskite film increased from20.72%to 23.58%,upon addition of 4-TBA.Furthermore,the moisture and thermal stability of 4-TBAtreated films and devices was significantly enhanced,along with prolonged device performance.Our work provides guidance on selecting the structure and functional groups that are essential for surface defect passivation and the production of high-quality perovskites.
基金supported by the Doctoral Research Start-up Project of Yuncheng University(YQ-2023067)Project of Shanxi Natural Science Foundation(202303021211189)+2 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provinces(20220036)Shanxi Province Intelligent Optoelectronic Sensing Application Technology Innovation CenterShanxi Province Optoelectronic Information Science and Technology Laboratory,Yuncheng University。
文摘Metal nanoparticles with high surface area and high electrochemical activity exhibit excellent catalytic performance in the photocatalytic reduction of carbon dioxide(CO_(2)).However,poor stability,small specific surface area,and less active sites limits its solar energy utilization.Hydrothermal method was utilized to synthesize the bimetallic material of Cu_(x)Co_(1-x)in this work.Co was loaded onto the Cu surface due to the electrons generated by the surface plasmon resonance(SPR)effect occurring on the Cu surface.Cu_(x)Co_(1-x)exhibits high photocatalytic conversion of CO_(2)efficiency under irradiation,which mainly because the Co nanoparticles on the surface of Cu can be used as cocatalysts to enhance the photocharge transfer.Cu_(0.6)Co_(0.4)exhibits the comparatively best photocatalytic conversion efficiency of CO_(2)in the first 6 h light irradiation.The yields of CO and CH_(4)reached 35.26 and 2.71μmol/(g·h),respectively.Upon illumination,electrons were produced,with the majority of them moving towards the interface.This movement contributes to the increased lifetime of photogenerated electron-hole pairs,which in turn boosts the photocatalytic efficiency.The findings of this research provide significant insights for creating photocatalysts that are both highly effective and stable in CO_(2)reduction processes.
基金Supporting Program for funding this work under Project number(RSP2024R328),King Saud University,Riyadh,Saudi Arabia.
文摘The sedimentary geochemistry of St.Martin’s Island is important to determine the origin of the source rock,paleo weathering,tectonic setting,sediment recycling,maturity,sorting,redox condition,and paleo salinity of the sediments.Major oxides,trace elements,and rare earth elements(REEs)obtained from the INAA technique are presented by analyzing the sediment samples collected from the shoreline of St.Martin’s Island,Bangladesh.The elemental ratios,comparison with average upper continental crust(UCC),binary diagrams(Th/Sc vs.Sc,La/Th vs.Hf,Th/Co vs.La/Sc),and chondrite normalized REE patterns exhibit substantial LREE enrichment,relatively fl at HREE fractionation,considerable negative Eu anomalies(average:0.72),indicates the derivation from a source dominated by felsic rock,with contribution from intermediate source and mafi c component.Sediments from St.Martin’s Island exhibit the deposition of sediments in transitional environments of active and passive continental margin settings.Weathering indices value of CIA,PIA,CIW,CIX,and K 2 O/Rb ratio show moderate chemical weathering,indicating that the sediments are chemically mature.Sedimentary redox indicative proxies,such as U/Th,V/Cr,and V/Sc,show an oxic depositional environment during sediment deposition.The intermediate CIA and other weathering index values of the St.Martin’s sediments show that the area had semiarid and humid climatic conditions throughout the deposition.The Rb/K ratio of the St.Martin’s sediments suggests that the development and deposition of the sedimentary sequence of St.Martin’s Island mainly occurred in a brackish water environment during the geological past.
文摘The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.
基金National Key Research and Development Program of China(2022YFE0206300)National Natural Science Foundation of China(U21A2081,22075074,22209047)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2024A1515011620)Hunan Provincial Natural Science Foundation of China(2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation(2023YCII0119)。
文摘Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.
基金National Natural Science Foundation of China(32201491)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)The authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1101-02”.
文摘Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.
文摘We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.
文摘The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical line with its length indicating the bandwidth(70-130 kHz).The horizontal error bars signify the end time uncertainty.The vertical dashed line marks the SGRE end(06:28 UT,September 7);the horizontal dashed line represents the gamma-ray background.The shock arrival time at 1 au is labeled“SH”(Gopalswamy et al.2018).
