In this paper,we investigate the optical properties of a non-rotating charged black hole(BH)in the Einstein-Maxwell-scalar(EMS)theory,together with a plasma medium.We first consider the photon sphere and shadow radius...In this paper,we investigate the optical properties of a non-rotating charged black hole(BH)in the Einstein-Maxwell-scalar(EMS)theory,together with a plasma medium.We first consider the photon sphere and shadow radius under the impact of the plasma medium existing in the environment surrounding the BH in the EMS theory.We show that the radius of the photon sphere and the BH shadow decrease under the influence of the parameterβ.We further study gravitational weak lensing in detail by adapting general methods and derive the light ray's deflection angle around the BH together with the plasma environment.It is found that for uniform plasma,the deflection angle increases with the rise of the plasma parameter,whereas it decreases with the increase of the plasma parameter for non-uniform plasma.Besides,we also study the magnification of image brightness.展开更多
We investigate the impact of the modified gravity(MOG)field and the quintessence scalar field on horizon evolution,black hole(BH)shadow and the weak gravitational lensing around a static spherically symmetric BH.We fi...We investigate the impact of the modified gravity(MOG)field and the quintessence scalar field on horizon evolution,black hole(BH)shadow and the weak gravitational lensing around a static spherically symmetric BH.We first begin to write the BH metric associated with the MOG parameter and quintessence scalar field.We then determine the BH shadow and obtain numerical solutions for the photon sphere and shadow radius.We show that the MOG(α)and the quintessence(c)parameters have a significant impact on the BH shadow and photon sphere.Based on the analysis,we further show that the combined effects of the MOG parameter and quintessence field can increase the values of BH shadow and photon sphere radii.We also obtain constraints on the BH parameters by applying the observational data of Sgr A^(★)and M87^(★).Finally,we consider the weak deflection angle of BH within the context of the Gauss-Bonnet theorem(GBT)and show that the combined effects of the MOG and quintessence parameters do make the value of the deflection angle increase,and find this remarkable property is in good agreement with the physical meaning of both parameters that can maintain the strong gravitational field in the surrounding environment of a BH.展开更多
In this study,we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the Dyonic ModMax(DM)spacetime,also accounting for models with nonuniform plasma distributio...In this study,we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the Dyonic ModMax(DM)spacetime,also accounting for models with nonuniform plasma distributions.By analyzing various gravitational lens models,we compare corrections to vacuum lensing due to gravitational effects within plasma and plasma inhomogeneity,finding that these effects could be observed in hot gas within galaxy clusters.Starting with the orbits of photons around a black hole in DM,we investigate the shadow and weak gravitational lensing phenomena.Utilizing observational data from the Event Horizon Telescope for M87*and SgrA*,we constrain parameters within DM gravity.To connect our findings to observations,we examine the magnification and positioning of lensed images,along with the weak deflection angle and magnification for sources near different galaxies.展开更多
BACKGROUND: This study aimed to explore the risk factors associated with intensive care unitacquired weakness(ICU-AW) in critically ill patients at risk of malnutrition and to evaluate the efficacy of early enteral nu...BACKGROUND: This study aimed to explore the risk factors associated with intensive care unitacquired weakness(ICU-AW) in critically ill patients at risk of malnutrition and to evaluate the efficacy of early enteral nutrition(EEN) and the role of biomarkers in managing ICU-AW.METHODS: This retrospective, observational cohort study included 180 patients at risk of malnutrition admitted to the emergency intensive care unit of the First Affiliated Hospital of Xiamen University Hospital from January 2022 to December 2023. Patients were divided into ICU-AW group and non-ICU-AW group according to whether they developed ICU-AW, or categorized into EEN and parenteral nutrition(PN) groups according to nutritional support. ICU-AW was diagnosed using the Medical Research Council score. The primary outcome was the occurrence of ICU-AW.RESULTS: The significant factors associated with ICU-AW included age, sex, type of nutritional therapy, mechanical ventilation(MV), body mass index(BMI), blood urea nitrogen(BUN), and creatinine(Cr) levels(P<0.05). The PN group developed ICU-AW earlier than did the EEN group, with a significant difference observed(log-rank P<0.001). Among biomarkers for ICU-AW, the mean prealbumin(PAB)/C-reactive protein(CRP) ratio had the highest diagnostic accuracy(area under the curve [AUC] 0.928, 95% confidence interval [95% CI] 0.892–0.946), surpassing the mean Cr/BUN ratio(AUC 0.740, 95% CI 0.663–0.819) and mean transferrin levels(AUC 0.653, 95% CI 0.574–0.733).CONCLUSION: Independent risk factors for ICU-AW include female sex, advanced age, PN, MV, lower BMI, and elevated BUN and Cr levels. EEN may potentially delay ICU-AW onset, and the PAB/CRP ratio may be an effective diagnostic marker for this condition.展开更多
We study the lensing phenomena of the strong gravity regime of five-dimensional charged,equally rotating black holes with a cosmological constant,familiarly known as the Cvetic–Lu–Pope(CLP)black holes.These black ho...We study the lensing phenomena of the strong gravity regime of five-dimensional charged,equally rotating black holes with a cosmological constant,familiarly known as the Cvetic–Lu–Pope(CLP)black holes.These black holes are characterized by three observable parameters,the mass M,the charge Q and the angular momentum J,in addition to the cosmological constant.We investigate the strong gravitational lensing observables,mainly the photon sphere radius,the minimum impact parameter,the deflection angle,the angular size,and the magnification of the relativistic images.We model the M87 and SgrA*for these observables.We also focus on the relativistic time delay effect in the strong-field regime of gravity and the impact of the observable on it.The analytical expressions for the observables of the relativistic images with vanishing angular momentum(j=0)are discussed in some detail.We shed a light on the gravitational time delay effect by incorporating the lensing observables.The gravitational time delay has a direct consequence on the photon sphere radius and hence on the quasinormal modes.展开更多
When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a l...When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a large number of low-mass free-floating planet events(FFPs)from a bulge microlensing survey.We assess the feasibility of detecting satellites(a.k.a.,exomoons)orbiting FFPs by simulating CSST light curves and calculating the detection efficiency as a function of satellite-to-planet mass ratios(q)and projected separations(s)in units of the Einstein radius.For a Neptune-class FFP in the Galactic disk with a Sun-like star as the microlensed source,CSST can detect Earth-mass satellites over a decade of separations(∼0.01-0.1 au)and has sensitivity down to Moon-mass satellites(q∼10^(−3))at s^(∼1).CSST also has some sensitivity to detect Moon-mass satellites at s∼2(∼0.02 au)orbiting an Earth-mass FFP in the disk.CSST has substantially reduced sensitivity for detecting satellites when the source star is an M dwarf,compared to a Sun-like source.We also calculate the satellite detection efficiency for the dedicated microlensing survey of the Roman Space Telescope(Roman),which demonstrates greater sensitivity than CSST,particularly for M-dwarf sources.Notably,some of the Neptune-Earth systems detectable by CSST and Roman may exhibit significant tidal heating.展开更多
Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by hig...Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.展开更多
The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces...The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.展开更多
The successful development of shale oil and gas reservoirs is the biggest technological revolution in the oil and gas industry.Its key technologies are horizontal well drilling and fracturing,which are based on unders...The successful development of shale oil and gas reservoirs is the biggest technological revolution in the oil and gas industry.Its key technologies are horizontal well drilling and fracturing,which are based on understanding the mechanical properties of reservoir rocks.Therefore,it is critical to obtain the reservoir mechanical parameters quickly,efficiently,and inexpensively.In this study,shale samples were collected from three basins in Southwest China,and the elastic modulus of shale in the indentation depth range of 0-5000 nm was obtained by nanoindentation experiments.Experimental results showed that different indentation depths had different physical characteristics.The shallower depths had the mechanical properties of single minerals,while the deeper depths had the mechanical properties of a multi-mineral composite.The difference between the two represented the cementation strength between the mineral particles.The error between the calculation results of the existing equivalent medium theoretical model and experimental data reached 324%.In this study,a weak cementation model was adopted,and three parameters obtained by nanoindentation experiments were considered:the soft component volume content,intergranular cementation strength,and mineral particle size.This solved the problem of assuming rather than calculating the values of some parameters in the existing model and realized the prediction of the macroscopic mechanical parameters of shale.The calculation error was reduced to less than 20%,and the test method and calculation model can be popularized and applied in engineering.展开更多
With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence...With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence the timelines of highway and railway projects.Therefore,the construction of tunnels with TBMs becomes a preferred option.In this study,a comparative analysis between TBM and the New Austrian Tunneling Method(NATM)for tunnel construction is performed in the construction of the T1 tunnel with a diameter of 13 m,which is the longest tunnel in the E?me-Salihli section of Ankara-izmir High-Speed Railway Project(Türkiye).The selection of TBM type,measures taken in problematic sections,and application issues of TBM are discussed.The impact of correct description of geological and geotechnical conditions on both selection and performance of TBM is presented.An earth pressure balanced type TBM is chosen for the construction of the T1 tunnel.Because of the additional engineering measures taken before excavation in problematic areas,the tunnel was completed with great success within the initially planned timeframe.From this point of view,this study is an important case and may contribute to worldwide tunneling literature.展开更多
Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified W...Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.展开更多
High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage...High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage range.In addition,the utilization of flammable organic solvents would increase safety risks in the high temperature environment.Herein,an electrolyte consisting of flame-retardant solvents with lower highest occupied molecular orbital(HOMO)level and LiDFOB salt is proposed to address above two issues.As a result,a thin and robust cathode-electrolyte interface containing rich LiF and Li-B-O compounds is formed on the cathode to effectively suppress electrolyte decomposition in the high operating voltage.The NCM811||Li cell paired with this designed electrolyte possesses a capacity retention of 72%after 300 cycles at 55℃.This work provides insights into developing electrolyte for stable high-nickel cathode operated in the high temperature.展开更多
Among the four candidate algorithms in the fourth round of NIST standardization,the BIKE(Bit Flipping Key Encapsulation)scheme has a small key size and high efficiency,showing good prospects for application.However,th...Among the four candidate algorithms in the fourth round of NIST standardization,the BIKE(Bit Flipping Key Encapsulation)scheme has a small key size and high efficiency,showing good prospects for application.However,the BIKE scheme based on QC-MDPC(Quasi Cyclic Medium Density Parity Check)codes still faces challenges such as the GJS attack and weak key attacks targeting the decoding failure rate(DFR).This paper analyzes the BGF decoding algorithm of the BIKE scheme,revealing two deep factors that lead to DFR,and proposes a weak key optimization attack method for the BGF decoding algorithm based on these two factors.The proposed method constructs a new weak key set,and experiment results eventually indicate that,considering BIKE’s parameter set targeting 128-bit security,the average decryption failure rate is lowerly bounded by.This result not only highlights a significant vulnerability in the BIKE scheme but also provides valuable insights for future improvements in its design.By addressing these weaknesses,the robustness of QC-MDPC code-based cryptographic systems can be enhanced,paving the way for more secure post-quantum cryptographic solutions.展开更多
The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates signi...The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates significantly and exceeds the limitation,which seriously threaten the safe supply of electricity.In this paper,the underlying theoretical mechanism and dominant force behind the maximum PLL frequency deviation are revealed.Accordingly,two feasible approaches are proposed to enhance the PLL frequency stability with validations in experimental results.展开更多
Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of...Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of bedding slopes,each with different weak interlayers:one with a homogeneous weak layer and another with discontinuous interfaces.Shaking table tests were conducted to compare their seismic performance.The results show that the peak ground acceleration(PGA)values above the weak interlayer in model A were significantly higher than those in model B,with the differences increasing as the input wave amplitude increased.The peak earth pressure(PEP)values at the tensile failure boundary at the rear edge of model A were also higher,whereas those within the weak layer at the toe of model A were lower than those in model B.Deformation analysis revealed that the maximum principal strain in model A initially appeared at the upper part of the tensile failure boundary,while the maximum shear strain was concentrated near the rear edge within the weak layer.In contrast,model B exhibited the opposite strain distribution.These findings provide insight into the impact of weak interlayers on the dynamic response and deformation of bedding slopes,highlighting the importance of considering this factor in seismic landslide investigations and failure mode predictions.展开更多
Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and of...Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.11675143the National Key Research and Development Program of China under Grant No.2020YFC2201503。
文摘In this paper,we investigate the optical properties of a non-rotating charged black hole(BH)in the Einstein-Maxwell-scalar(EMS)theory,together with a plasma medium.We first consider the photon sphere and shadow radius under the impact of the plasma medium existing in the environment surrounding the BH in the EMS theory.We show that the radius of the photon sphere and the BH shadow decrease under the influence of the parameterβ.We further study gravitational weak lensing in detail by adapting general methods and derive the light ray's deflection angle around the BH together with the plasma environment.It is found that for uniform plasma,the deflection angle increases with the rise of the plasma parameter,whereas it decreases with the increase of the plasma parameter for non-uniform plasma.Besides,we also study the magnification of image brightness.
基金supported by the National Natural Science Foundation of China under Grant No. 11675143the National Key Research and Development Program of China under Grant No. 2020YFC2201503the support from Research Grant F-FA-2021-432 of the Ministry of Higher Education, Science and Innovations of the Republic of Uzbekistan。
文摘We investigate the impact of the modified gravity(MOG)field and the quintessence scalar field on horizon evolution,black hole(BH)shadow and the weak gravitational lensing around a static spherically symmetric BH.We first begin to write the BH metric associated with the MOG parameter and quintessence scalar field.We then determine the BH shadow and obtain numerical solutions for the photon sphere and shadow radius.We show that the MOG(α)and the quintessence(c)parameters have a significant impact on the BH shadow and photon sphere.Based on the analysis,we further show that the combined effects of the MOG parameter and quintessence field can increase the values of BH shadow and photon sphere radii.We also obtain constraints on the BH parameters by applying the observational data of Sgr A^(★)and M87^(★).Finally,we consider the weak deflection angle of BH within the context of the Gauss-Bonnet theorem(GBT)and show that the combined effects of the MOG and quintessence parameters do make the value of the deflection angle increase,and find this remarkable property is in good agreement with the physical meaning of both parameters that can maintain the strong gravitational field in the surrounding environment of a BH.
基金partly supported by Research Grants FZ-20200929344 and F-FA-2021-510 of the Uzbekistan Ministry for Innovative DevelopmentTUBITAKSCOAP3 for their support。
文摘In this study,we examine the effects of weak gravitational lensing and determine the shadow radius around black holes within the Dyonic ModMax(DM)spacetime,also accounting for models with nonuniform plasma distributions.By analyzing various gravitational lens models,we compare corrections to vacuum lensing due to gravitational effects within plasma and plasma inhomogeneity,finding that these effects could be observed in hot gas within galaxy clusters.Starting with the orbits of photons around a black hole in DM,we investigate the shadow and weak gravitational lensing phenomena.Utilizing observational data from the Event Horizon Telescope for M87*and SgrA*,we constrain parameters within DM gravity.To connect our findings to observations,we examine the magnification and positioning of lensed images,along with the weak deflection angle and magnification for sources near different galaxies.
文摘BACKGROUND: This study aimed to explore the risk factors associated with intensive care unitacquired weakness(ICU-AW) in critically ill patients at risk of malnutrition and to evaluate the efficacy of early enteral nutrition(EEN) and the role of biomarkers in managing ICU-AW.METHODS: This retrospective, observational cohort study included 180 patients at risk of malnutrition admitted to the emergency intensive care unit of the First Affiliated Hospital of Xiamen University Hospital from January 2022 to December 2023. Patients were divided into ICU-AW group and non-ICU-AW group according to whether they developed ICU-AW, or categorized into EEN and parenteral nutrition(PN) groups according to nutritional support. ICU-AW was diagnosed using the Medical Research Council score. The primary outcome was the occurrence of ICU-AW.RESULTS: The significant factors associated with ICU-AW included age, sex, type of nutritional therapy, mechanical ventilation(MV), body mass index(BMI), blood urea nitrogen(BUN), and creatinine(Cr) levels(P<0.05). The PN group developed ICU-AW earlier than did the EEN group, with a significant difference observed(log-rank P<0.001). Among biomarkers for ICU-AW, the mean prealbumin(PAB)/C-reactive protein(CRP) ratio had the highest diagnostic accuracy(area under the curve [AUC] 0.928, 95% confidence interval [95% CI] 0.892–0.946), surpassing the mean Cr/BUN ratio(AUC 0.740, 95% CI 0.663–0.819) and mean transferrin levels(AUC 0.653, 95% CI 0.574–0.733).CONCLUSION: Independent risk factors for ICU-AW include female sex, advanced age, PN, MV, lower BMI, and elevated BUN and Cr levels. EEN may potentially delay ICU-AW onset, and the PAB/CRP ratio may be an effective diagnostic marker for this condition.
基金supported by the National Natural Science Foundation of China under Grants Nos.12475056,12347177,and 12247101,the 111 Project under Grant No.B20063Lanzhou City's scientific research funding subsidy to Lanzhou Universitythe Gansu Province Major Scientific and Technological Special Project。
文摘We study the lensing phenomena of the strong gravity regime of five-dimensional charged,equally rotating black holes with a cosmological constant,familiarly known as the Cvetic–Lu–Pope(CLP)black holes.These black holes are characterized by three observable parameters,the mass M,the charge Q and the angular momentum J,in addition to the cosmological constant.We investigate the strong gravitational lensing observables,mainly the photon sphere radius,the minimum impact parameter,the deflection angle,the angular size,and the magnification of the relativistic images.We model the M87 and SgrA*for these observables.We also focus on the relativistic time delay effect in the strong-field regime of gravity and the impact of the observable on it.The analytical expressions for the observables of the relativistic images with vanishing angular momentum(j=0)are discussed in some detail.We shed a light on the gravitational time delay effect by incorporating the lensing observables.The gravitational time delay has a direct consequence on the photon sphere radius and hence on the quasinormal modes.
基金supported by the National Natural Science Foundation of China(grant No.12133005)the China Manned Space Program with grant No.CMS-CSST-2025-A16.S.D.acknowledges the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘When a planet is ejected from its star-planet system due to dynamical interactions,its satellite may remain gravitationally bound to the planet.The Chinese Space Station Telescope(CSST)will be capable of detecting a large number of low-mass free-floating planet events(FFPs)from a bulge microlensing survey.We assess the feasibility of detecting satellites(a.k.a.,exomoons)orbiting FFPs by simulating CSST light curves and calculating the detection efficiency as a function of satellite-to-planet mass ratios(q)and projected separations(s)in units of the Einstein radius.For a Neptune-class FFP in the Galactic disk with a Sun-like star as the microlensed source,CSST can detect Earth-mass satellites over a decade of separations(∼0.01-0.1 au)and has sensitivity down to Moon-mass satellites(q∼10^(−3))at s^(∼1).CSST also has some sensitivity to detect Moon-mass satellites at s∼2(∼0.02 au)orbiting an Earth-mass FFP in the disk.CSST has substantially reduced sensitivity for detecting satellites when the source star is an M dwarf,compared to a Sun-like source.We also calculate the satellite detection efficiency for the dedicated microlensing survey of the Roman Space Telescope(Roman),which demonstrates greater sensitivity than CSST,particularly for M-dwarf sources.Notably,some of the Neptune-Earth systems detectable by CSST and Roman may exhibit significant tidal heating.
基金supported by the National Natural Science Foundation of China(No.52472225)the Science and Technology Plan Project of Shenzhen(No.20220808165025003),China。
文摘Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current.
基金supported by the National Key Research and Development Program of China(No.2019YFC1803501)the National Natural Science Foundation of China(No.52074357)+2 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ30713)the Vanadium Titanium Union Foundationthe Project of Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources,Ministry of Natural Resources,China。
文摘The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.
基金supported by the Key R&D Program Project of Xinjiang Province(2024B01013)the National Key Research and Development Program of China(2022YFE0129800).
文摘The successful development of shale oil and gas reservoirs is the biggest technological revolution in the oil and gas industry.Its key technologies are horizontal well drilling and fracturing,which are based on understanding the mechanical properties of reservoir rocks.Therefore,it is critical to obtain the reservoir mechanical parameters quickly,efficiently,and inexpensively.In this study,shale samples were collected from three basins in Southwest China,and the elastic modulus of shale in the indentation depth range of 0-5000 nm was obtained by nanoindentation experiments.Experimental results showed that different indentation depths had different physical characteristics.The shallower depths had the mechanical properties of single minerals,while the deeper depths had the mechanical properties of a multi-mineral composite.The difference between the two represented the cementation strength between the mineral particles.The error between the calculation results of the existing equivalent medium theoretical model and experimental data reached 324%.In this study,a weak cementation model was adopted,and three parameters obtained by nanoindentation experiments were considered:the soft component volume content,intergranular cementation strength,and mineral particle size.This solved the problem of assuming rather than calculating the values of some parameters in the existing model and realized the prediction of the macroscopic mechanical parameters of shale.The calculation error was reduced to less than 20%,and the test method and calculation model can be popularized and applied in engineering.
文摘With recent technological advancements,tunnel boring machines(TBM)have developed and exhibited high performance in large diameters and weak ground conditions.Tunnels are crucial structures that significantly influence the timelines of highway and railway projects.Therefore,the construction of tunnels with TBMs becomes a preferred option.In this study,a comparative analysis between TBM and the New Austrian Tunneling Method(NATM)for tunnel construction is performed in the construction of the T1 tunnel with a diameter of 13 m,which is the longest tunnel in the E?me-Salihli section of Ankara-izmir High-Speed Railway Project(Türkiye).The selection of TBM type,measures taken in problematic sections,and application issues of TBM are discussed.The impact of correct description of geological and geotechnical conditions on both selection and performance of TBM is presented.An earth pressure balanced type TBM is chosen for the construction of the T1 tunnel.Because of the additional engineering measures taken before excavation in problematic areas,the tunnel was completed with great success within the initially planned timeframe.From this point of view,this study is an important case and may contribute to worldwide tunneling literature.
基金supported by Hengyang City,Hunan Province Science and Technology Innovation Project(No.202250045319)the National Natural Science Foundation of China(Nos.11375084,21808125)the Scientific Research Planning Project of Jilin Provincial Education Department(No.JJKH20241249KJ)。
文摘Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.
基金supported by the National Key Research and Development Program of China(2022YFB3803400)。
文摘High-nickel cathode LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)could enable lithium-ion batteries(LIBs)with high energy density.However,excessive decomposition of the electrolyte would happen in the high operating voltage range.In addition,the utilization of flammable organic solvents would increase safety risks in the high temperature environment.Herein,an electrolyte consisting of flame-retardant solvents with lower highest occupied molecular orbital(HOMO)level and LiDFOB salt is proposed to address above two issues.As a result,a thin and robust cathode-electrolyte interface containing rich LiF and Li-B-O compounds is formed on the cathode to effectively suppress electrolyte decomposition in the high operating voltage.The NCM811||Li cell paired with this designed electrolyte possesses a capacity retention of 72%after 300 cycles at 55℃.This work provides insights into developing electrolyte for stable high-nickel cathode operated in the high temperature.
基金funded by Beijing Institute of Electronic Science and Technology Postgraduate Excellence Demonstration Course Project(20230002Z0452).
文摘Among the four candidate algorithms in the fourth round of NIST standardization,the BIKE(Bit Flipping Key Encapsulation)scheme has a small key size and high efficiency,showing good prospects for application.However,the BIKE scheme based on QC-MDPC(Quasi Cyclic Medium Density Parity Check)codes still faces challenges such as the GJS attack and weak key attacks targeting the decoding failure rate(DFR).This paper analyzes the BGF decoding algorithm of the BIKE scheme,revealing two deep factors that lead to DFR,and proposes a weak key optimization attack method for the BGF decoding algorithm based on these two factors.The proposed method constructs a new weak key set,and experiment results eventually indicate that,considering BIKE’s parameter set targeting 128-bit security,the average decryption failure rate is lowerly bounded by.This result not only highlights a significant vulnerability in the BIKE scheme but also provides valuable insights for future improvements in its design.By addressing these weaknesses,the robustness of QC-MDPC code-based cryptographic systems can be enhanced,paving the way for more secure post-quantum cryptographic solutions.
基金supported by the National Natural Science Foundation of China under Grant 52407069the Science and Technology Project of Zhejiang Province under Grant 2024C01254the China Postdoctoral Science Foundation under Grant 2024T170766 and 2024M762824。
文摘The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates significantly and exceeds the limitation,which seriously threaten the safe supply of electricity.In this paper,the underlying theoretical mechanism and dominant force behind the maximum PLL frequency deviation are revealed.Accordingly,two feasible approaches are proposed to enhance the PLL frequency stability with validations in experimental results.
基金funding support from the National Nature Science Foundation of China(Grant No.41931296)the Open Research Project of Sichuan Provincial Key Laboratory for Major Hazard Source Monitoring and Control(Grant No.KFKT2023-4)the 57#Project(Grant No.JH2024015).
文摘Weak interlayers play a crucial role in the seismic performance of bedding slopes;however,the effects of structural surface development within these layers remain underexplored.This study presents two scaled models of bedding slopes,each with different weak interlayers:one with a homogeneous weak layer and another with discontinuous interfaces.Shaking table tests were conducted to compare their seismic performance.The results show that the peak ground acceleration(PGA)values above the weak interlayer in model A were significantly higher than those in model B,with the differences increasing as the input wave amplitude increased.The peak earth pressure(PEP)values at the tensile failure boundary at the rear edge of model A were also higher,whereas those within the weak layer at the toe of model A were lower than those in model B.Deformation analysis revealed that the maximum principal strain in model A initially appeared at the upper part of the tensile failure boundary,while the maximum shear strain was concentrated near the rear edge within the weak layer.In contrast,model B exhibited the opposite strain distribution.These findings provide insight into the impact of weak interlayers on the dynamic response and deformation of bedding slopes,highlighting the importance of considering this factor in seismic landslide investigations and failure mode predictions.
基金supported by the Basic Science Research Program(RS-2024-00344021,RS-2023-00261543,and RS-202300257666)through the National Research Foundation of Korea(NRF),the National Research Council of Science(000)Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(RS-2024-00420590,HRD Program for Industrial Innovation)The computational resources were provided by KITSI(KSC-2024-CRE-0143)。
文摘Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.
