The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic under...The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic understanding of the spatial distribution of the EEI interface layer and the dissolve of Fe ions,especially in terms of the mechanism of the cathode-electrolyte interphase(CEI),solid electrolyte interphase(SEI),and iron dissolution.In this study,aged cells were subjected to continuous activation with constant current and multi-step segmented indirect activation(IA)and analyzed for capacity fade,impedance growth,and active Li^(+)mass loss at the EEI and nanoscale levels.The interaction between dissolved Fe^(2+)and the EEI in LFP/graphite pouch batteries was proposed and verified.The findings indicate that during IA process,the electric field facilitates the migration of solvated ions toward the electrodes,while simultaneously inhibiting the formation of organic species such as ROCO_(2)Li.The SEI primarily consists of a mixture of organic and inorganic small molecules,forming a continuous and uniform film on the electrode surface.This study demonstrates that IA favors the formation of a uniform EEI and offers constructive insights for advancing accelerated lifetime prediction strategies in lithium-ion batteries.展开更多
In this editorial,the authors of this paper comment on the article by Bokov et al published in the recent issue of World Journal of Orthopedics.We reviewed a general overview of oblique lumbar interbody fusions(OLIF)a...In this editorial,the authors of this paper comment on the article by Bokov et al published in the recent issue of World Journal of Orthopedics.We reviewed a general overview of oblique lumbar interbody fusions(OLIF)and lateral lumbar interbody fusions(LLIF),their indications and complications as an increasingly popular minimally invasive technique to address several lumbar pathologies.This editorial thoroughly discusses and reviews the literature regarding factors affecting outcomes of indirect decompression utilized through OLIF and LLIF procedures.Several parameters play a critical role in patient outcomes including restoration of disc height,foraminal height,central canal squared,and foraminal area.The indirect decompression allows for unbuckling of the ligamentum flavum which can significantly decompress the neural elements as well as aid in reduction of spondylolisthesis.However,the authors further highlight the limitations of indirect decompression and factors that may predict unsuccessful outcomes including bony foraminal stenosis,severe central canal stenosis,and osteoporosis.As a result,failure of indirect decompression can lead to persistent pain,radiculopathy and unsatisfied patients.Spinal surgeons may be left to reimage patients and consider additional procedures with direct decompression.展开更多
Immune modulation is crucial for male reproduction and fertility.Metals and metalloids(metals)have been extensively studied for their immunomodulatory effects.Whether metal exposure affects semen quality through immun...Immune modulation is crucial for male reproduction and fertility.Metals and metalloids(metals)have been extensively studied for their immunomodulatory effects.Whether metal exposure affects semen quality through immune modulation is unclear.In the present study,we explored the associations between exogenous metals within immune cells,immune cell proportions,and semen quality among 84 healthy men who repeatedly provided 266 semen samples over 90 days.We employed mass cytometry(CyTOF)technology to identify immune cells in semen and measured exogenous metals in these cells at the single-cell resolution.After adjusting for potential confounders,most detected metals in immune cells were inversely associated with the proportion of immune cells in semen samples(all p<0.05),indicating the adverse effects of exogenous metals on immune cells.The proportion of immune cells showed N-shaped,nonlinear associations with sperm concentration,total count,progressive motility,and total motility.Mediation analyses showed that the percentage of indirect effects of exogenous metals on sperm quality parameters via immune cells ranged from 15.11%to 54.29%.Overall,our findings unravel the indirect effects of exogenous metal exposure on male reproductive health via immune cells,contributing valuable insights into the complex interplay between environmental factors,immune cells,and human semen quality.展开更多
The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat sto...The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.展开更多
This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+...This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+n▽Ф;▽·u=0,x∈Ω,t>0 in a bounded and smooth domainΩ⊂ℝ2 with no-flux/no-flux/no-flux/no-slip boundary conditions,whereΦ∈W2,∞(Ω).A recent literature[Dai F,Liu B.J Differential Equations,2023,369:115–155]has proved that for all reasonably regular initial data,the associated initial-boundary value problem possesses a global classical solution,but qualitative information on the behavior of solution has never been touched so far.In stark contrast to the positive effect of indirect signal consumption mechanism on the global solvability of system,the analysis of asymptotic behavior of solution to the system with indirect signal consumption is essentially complicated than that with direct signal consumption because the favorable coupled structure between cells and signal is broken down by the indirect signal consumption mechanism.The present study shows that the global classical solution exponentially stabilizes toward the corresponding spatially homogeneous equilibria under a smallness condition on the initial cell mass.In comparison to the previously known result concerning the uniform convergence of solution to the system with direct signal consumption,our result inter alia provides a more in-depth understanding on the asymptotic behavior of solution.展开更多
Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge ...Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge in literature on economic modeling methodologies for estimating indirect economic impacts of disasters and the recovery of economic activity over time.In this review,we present a framework for categorizing modeling approaches that assess indirect economic impacts across natural hazards and anthropogenic disasters such as cyber attacks.We first conduct a comparative analysis of macroeconomic models,focusing on the approaches capturing sectoral interdependencies.These include the Leontief Input-Output(I/O)model,the Inoperability Input-Output Model(IIM),the Dynamic Inoperability Input-Output Model(DIIM),the Adaptive Regional Input-Output(ARIO)model,and the Computable General Equilibrium(CGE)model and its extensions.We evaluate their applicability to disaster scenarios based on input data availability,the compatibility of model assumptions,and output capabilities.We also reveal the functional relationships of input data and output metrics across economic modeling approaches for inter-sectoral impacts.Furthermore,we examine how the damage mechanisms posed by different types of disasters translate into model inputs and impact modeling processes.This synthesis provides guidance for researchers and practitioners in selecting and configuring models based on specific disaster scenarios.It also identifies the gaps in the literature,including the need for a deeper understanding of model performance reliability,key drivers of economic outcomes in different disaster contexts,and the disparities in modeling approach applications across various hazard types.展开更多
BACKGROUND Diabetic retinopathy(DR)is a major cause of visual impairment and blindness.However,the current DR biomarkers are insufficient for accurately predicting its onset.AIM To identify a novel marker for predicti...BACKGROUND Diabetic retinopathy(DR)is a major cause of visual impairment and blindness.However,the current DR biomarkers are insufficient for accurately predicting its onset.AIM To identify a novel marker for predicting the risk of developing DR in patients with type 2 diabetes mellitus(T2DM).METHODS We conducted a cross-sectional study involving 6993 hospitalized T2DM patients between 2013 and 2020.Patients were divided into two groups:The DR group and the non-DR group.Data were analyzed using univariate,correlation,multivariate,subgroup,and receiver operating characteristic curve analyses.RESULTS Total bilirubin,indirect bilirubin(IBIL),and direct bilirubin were negatively correlated with the risk of developing DR(P<0.001).Moreover,these three factors were all positively correlated with clinical indicators related to DR,including the estimated glomerular filtration rate,the albumin/creatinine ratio,and the 1,25-dihydroxyvitamin D3 level(P<0.001).After adjusting for multiple variables,greater IBIL levels remained independently associated with a lower risk of developing DR(odds ratio=0.500;95%confidence interval:0.363-0.686;P<0.001).The optimal IBIL cutoff point for predicting the risk of DR in male patients with elevated diastolic blood pressure was 0.655μmol/dL(area under the curve=0.662).CONCLUSION These findings suggest that IBIL could be a valuable biomarker for predicting DR risk,offering a noninvasive,cost-effective,and readily available clinical tool for the early identification of high-risk patients.Future multicenter and longitudinal studies are warranted to validate these findings and further explore the biological mechanisms underlying the protective role of IBIL in DR.展开更多
Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium...Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.展开更多
Uniaxial compressive strength(UCS)is a significant mechanical measure in rock engineering,key for classifying rock masses,conducting stability assessments,and guiding design processes.Over the past five decades,numero...Uniaxial compressive strength(UCS)is a significant mechanical measure in rock engineering,key for classifying rock masses,conducting stability assessments,and guiding design processes.Over the past five decades,numerous techniques and devices have emerged for UCS measurement.This paper presents a comprehensive literature review of existing methodologies and advancements in UCS testing,examining the theoretical foundations,testing equipment,data processing techniques,and criteria for selecting appropriate UCS testing methods.Additionally,the study highlights a shift toward automated,precise,and computational approaches with multiple inputs(i.e.multiple regression,machine learning,ML)for UCS prediction.Approximately 221 articles published by various researchers between 2000 and 2024 related to ML were reviewed,focusing on the application of ML models,including artificial neural networks(ANNs),adaptive-network-based fuzzy inference system(ANFIS),random forest(RF),support vector machine(SVM),and extreme gradient boosting(XGBoost),in UCS prediction.The review also observed the growing use of hybrid models integrating ML with optimization techniques,significantly improving UCS estimation.Numerous empirical correlations,both direct and indirect,have been established in the past several years based on the physical properties of rocks.However,utilizing these proposed equations to reliably estimate UCS remains challenging due to the variability in lithology,rock origin,and other factors.This study systematically presents the established correlation expressions,considering their lithology,the number of samples used to establish the expressions,the coefficient of determination(R^(2)),and the locations.This allows geologists and engineers to easily apply these established expressions in situations where direct estimation is not possible,enabling them to approximate UCS results.展开更多
BACKGROUND Routinely separating the ligamentum teres uteri(LTU)intraoperatively remains an unresolved issue for female children undergoing surgery for indirect inguinal hernia(IIH).AIM To identify the effect of LTU pr...BACKGROUND Routinely separating the ligamentum teres uteri(LTU)intraoperatively remains an unresolved issue for female children undergoing surgery for indirect inguinal hernia(IIH).AIM To identify the effect of LTU preservation in laparoscopic high hernia sac ligation(LHSL)in children with IIH.METHODS The participants were 100 female children with unilateral IIH admitted from April 2022 to January 2024 to the Pediatric Surgery Department of Zhangzhou Municipal Hospital of Fujian Province.They were categorized based on LTU retention into the control group(n=45 cases),which underwent LTU ligation intraoperatively,and the experimental group(55 cases),which had the LTU preserved intraoperatively.All children underwent LHSL.RESULTS This study comparatively analyzed the operation time,hospitalization time,blood loss,postoperative recurrence rate,and complications(repeated pain in the inguinal region,foreign body sensation in the inguinal region,bloody exudation at the inguinal incision,and incision infection),which were all comparable between the two groups.CONCLUSION The above results indicate that LTU preservation during LHSL exerts certain therapeutic benefits for children with IIH.LTU preservation does not increase hospitalization time,blood loss,postoperative recurrence rate,and complications,which is safe and feasible,compared with conventional LTU ligation.LHSL with LTU preservation should be performed if conditions permit,which is worth popularizing.展开更多
The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor ...The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.展开更多
The fatigue crack growth rate of a novel Ti-6Al-4V-1Mo titanium alloy,which is developed for laser directed energy deposition technique,was investigated before and after cyclic heat treatment(CHT).Changes in microstru...The fatigue crack growth rate of a novel Ti-6Al-4V-1Mo titanium alloy,which is developed for laser directed energy deposition technique,was investigated before and after cyclic heat treatment(CHT).Changes in microstructure,fracture surfaces,and crack growth paths were analyzed before and after CHT.Results indicate that in the stable crack growth region,the growth rates for the as-deposited and cyclic heat-treated specimens follow the relationships da/dN=1.8651×10^(−8)(ΔK)^(3.2271)and da/dN=1.4112×10^(−8)(ΔK)^(3.1125),respectively.Compared with that at the as-deposited state,the microstructure after CHT is transformed from a uniform basket-weave microstructure to a dual-phase microstructure consisting of near-sphericalαandβ-transformed matrix phases.The cyclic process also disrupts the continuity of the grain boundaryα(αGB)at the primaryβ-phase grain boundary.The coarsening of primaryαand the disruption ofαGB continuity are the primary factors to release stress concentration and promote crack deflection,thereby decreasing the fatigue crack growth rate.Additionally,the increased occurrence of crack branching,secondary cracking,and crack bridging in cyclic heat-treated specimens further reduces the crack driving force and slows the fatigue crack growth rate.展开更多
Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usu...Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usually involves complex procedures and extremely depends on unidirectional freezing technique.Herein,we propose a groundbreaking approach that leverages the assemblies of salting-out protein induced by ammonium metatungstate(AM)as the precursor,and then acquire directional three-dimensional carbon-based foams through simple pyrolysis.The electrostatic interaction between AM and protein ensures well dispersion of WC_(1−x)nanoparticles on carbon frameworks.The content of WC_(1−x)nanoparticles can be rationally regulated by AM dosage,and it also affects the electromagnetic(EM)properties of final carbon-based foams.The optimized foam exhibits exceptional EM absorption performance,achieving a remarkable minimum reflection loss of−72.0 dB and an effective absorption bandwidth of 6.3 GHz when EM wave propagates parallel to the directional pores.Such performance benefits from the synergistic effects of macroporous architecture and compositional design.Although there is a directional dependence of EM absorption,radar stealth simulation demonstrates that these foams can still promise considerable reduction in radar cross section with the change of incident angle.Moreover,COMSOL simulation further identifies their good performance in preventing EM interference among different electronic components.展开更多
The Cooling-Storage-Ring External-target Experiment(CEE)at the Heavy Ion Research Facility in Lanzhou(HIRFL)is designed to study the properties of nuclear matter created in heavy-ion collisions at beam energies from a...The Cooling-Storage-Ring External-target Experiment(CEE)at the Heavy Ion Research Facility in Lanzhou(HIRFL)is designed to study the properties of nuclear matter created in heavy-ion collisions at beam energies from a few hundred MeV/u up to 1 GeV/u.It aims to facilitate research on the quantum chromodynamics(QCD)phase structure in the high-baryondensity region.Collective flow is a fundamental observable in heavy-ion collision experiments,providing information on the bulk properties of the produced matter.Although the standard event plane method has been widely used to measure collective flow,it is still important to validate and optimize this method for the CEE spectrometer.In this paper,we study the experimental procedures for measuring directed flow in^(238)U+^(238)U collisions at 500 MeV/u,using event planes reconstructed by Multi-Wire Drift Chamber and Zero Degree Calorimeter,respectively.Jet AA Microscopic(JAM)transport generator is used to generate events,and the detector response is simulated by the CEE Fast Simulation(CFS)package.Finally,the optimal kinematic region for proton directed flow measurements is discussed for the future CEE experiment.展开更多
The rapid expansion of lithium-ion batteries in electric vehicles and grid-scale energy storage intensify the demand for sustainable recycling strategies.Traditional metallurgical recycling methods face significant ch...The rapid expansion of lithium-ion batteries in electric vehicles and grid-scale energy storage intensify the demand for sustainable recycling strategies.Traditional metallurgical recycling methods face significant challenges,including high energy consumption,environmental pollution,and inefficient critical metals recovery.In contrast,advanced direct recycling can selectively extract valuable metals while preserving cathode structure,achieving over 99%lithium recovery from lithium iron phosphate.Moreover,by directly repairing defects and crystal structures of spent materials,their electrochemical performance can be effectively restored.Due to significantly reduced energy and reagent inputs,direct recycling cuts processing costs by over 20% and reduces waste emissions by at least 40% compared to conventional methods,making it a promising low-carbon alternative.This review systematically integrates the recent advances in direct recycling of spent batteries as well as the limitations and challenges of existing technologies,and proposes future research pathways to promote resource recycling and sustainable development.展开更多
For a multi-frequency non-reciprocal optical device,we first realize multi-frequency optical non-reciprocal transmission using a non-Hermitian multi-mode resonator array.Practically,multi-frequency operation can add c...For a multi-frequency non-reciprocal optical device,we first realize multi-frequency optical non-reciprocal transmission using a non-Hermitian multi-mode resonator array.Practically,multi-frequency operation can add channels to the non-reciprocal optical device and the non-reciprocity can route optical signals and prevent the reverse flow of noise.Using the Scully–Lamb model and gain saturation effect,we accomplish dual-frequency non-reciprocal transmission by introducing nonlinearity into a linear array of four-mode resonators.The accomplishment is directly demonstrated by the non-reciprocal transmission phenomena present in the non-divergent peaks.For example,a directional cyclic amplifier is constructed with non-reciprocal units.Regarding potential applications,non-reciprocal optical systems can be employed in dual-frequency control,parallel information processing,photonic integrated circuits,optical devices and so on.展开更多
Objective:To explore the interventional room nursing and its application effects in patients with ischemic stroke treated with tirofiban combined with direct thrombectomy.Methods:A total of 61 patients with ischemic s...Objective:To explore the interventional room nursing and its application effects in patients with ischemic stroke treated with tirofiban combined with direct thrombectomy.Methods:A total of 61 patients with ischemic stroke admitted to our hospital from June 2024 to June 2025 were selected and divided into two groups using the red and blue ball method:the control group(n=30,receiving routine interventional room nursing)and the observation group(n=31,receiving additional tirofiban medication-specific nursing+individualized interventional nursing on the basis of routine nursing).The cerebral hemodynamic indicators,adverse reactions,effectiveness of complication nursing,and nursing satisfaction were compared between the two groups.Results:After 7 days of treatment,the observation group had lower cerebrovascular peripheral resistance and higher mean blood flow velocity and mean blood flow volume compared to the control group(all p<0.05).The observation group had a higher effectiveness rate of complication nursing than the control group,with a statistically significant difference(p<0.05).The nursing satisfaction in the observation group(96.77%)was higher than that in the control group(80.00%),with a statistically significant difference(χ^(2)=4.223,p=0.040<0.05).Conclusion:Tirofiban combined with direct thrombectomy can significantly improve cerebral hemodynamics,enhance the effectiveness of complication nursing,and increase patient satisfaction in patients with ischemic stroke.展开更多
BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Resear...BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Research in developing nations relating to the cost of treatment is scarce when compared with developed countries.Thus,the drug utilization research studies from developing nations are most needed,and their number has been growing.AIM To evaluate patterns of utilization of antipsychotic drugs and direct medical cost analysis in patients newly diagnosed with schizophrenia.METHODS The present study was observational in type and based on a retrospective cohort to evaluate patterns of utilization of antipsychotic drugs using World Health Organization(WHO)core prescribing indicators and anatomical therapeutic chemical/defined daily dose indicators.We also calculated direct medical costs for a period of 6 months.RESULTS This study has found that atypical antipsychotics are the mainstay of treatment for schizophrenia in every age group and subcategories of schizophrenia.The evaluation based on WHO prescribing indicators showed a low average number of drugs per prescription and low prescribing frequency of antipsychotics from the National List of Essential Medicines 2015 and the WHO Essential Medicines List 2019.The total mean drug cost of our study was 1396 Indian rupees.The total mean cost due to the investigation in our study was 1017.34 Indian rupees.Therefore,the total mean direct medical cost incurred on patients in our study was 4337.28 Indian rupees.CONCLUSION The information from the present study can be used for reviewing and updating treatment policy at the institutional level.展开更多
Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite...Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.展开更多
基金supported by the National Key R&D Program of China(2021YFB2401800)the support from Beijing Nova Program(20230484241)+2 种基金the support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)the support from Initial Energy Science&Technology Co.,Ltd(IEST)。
文摘The dissolution of iron from the cathode and electrode/electrolyte interface(EEI)during long cycles significantly accelerates the aging process of LiFePO_(4)(LFP)/graphite batteries;there is a lack of systematic understanding of the spatial distribution of the EEI interface layer and the dissolve of Fe ions,especially in terms of the mechanism of the cathode-electrolyte interphase(CEI),solid electrolyte interphase(SEI),and iron dissolution.In this study,aged cells were subjected to continuous activation with constant current and multi-step segmented indirect activation(IA)and analyzed for capacity fade,impedance growth,and active Li^(+)mass loss at the EEI and nanoscale levels.The interaction between dissolved Fe^(2+)and the EEI in LFP/graphite pouch batteries was proposed and verified.The findings indicate that during IA process,the electric field facilitates the migration of solvated ions toward the electrodes,while simultaneously inhibiting the formation of organic species such as ROCO_(2)Li.The SEI primarily consists of a mixture of organic and inorganic small molecules,forming a continuous and uniform film on the electrode surface.This study demonstrates that IA favors the formation of a uniform EEI and offers constructive insights for advancing accelerated lifetime prediction strategies in lithium-ion batteries.
文摘In this editorial,the authors of this paper comment on the article by Bokov et al published in the recent issue of World Journal of Orthopedics.We reviewed a general overview of oblique lumbar interbody fusions(OLIF)and lateral lumbar interbody fusions(LLIF),their indications and complications as an increasingly popular minimally invasive technique to address several lumbar pathologies.This editorial thoroughly discusses and reviews the literature regarding factors affecting outcomes of indirect decompression utilized through OLIF and LLIF procedures.Several parameters play a critical role in patient outcomes including restoration of disc height,foraminal height,central canal squared,and foraminal area.The indirect decompression allows for unbuckling of the ligamentum flavum which can significantly decompress the neural elements as well as aid in reduction of spondylolisthesis.However,the authors further highlight the limitations of indirect decompression and factors that may predict unsuccessful outcomes including bony foraminal stenosis,severe central canal stenosis,and osteoporosis.As a result,failure of indirect decompression can lead to persistent pain,radiculopathy and unsatisfied patients.Spinal surgeons may be left to reimage patients and consider additional procedures with direct decompression.
基金financially supported by the National Natural Science Foundation of China(42025704,22206033,82473581,22193052).
文摘Immune modulation is crucial for male reproduction and fertility.Metals and metalloids(metals)have been extensively studied for their immunomodulatory effects.Whether metal exposure affects semen quality through immune modulation is unclear.In the present study,we explored the associations between exogenous metals within immune cells,immune cell proportions,and semen quality among 84 healthy men who repeatedly provided 266 semen samples over 90 days.We employed mass cytometry(CyTOF)technology to identify immune cells in semen and measured exogenous metals in these cells at the single-cell resolution.After adjusting for potential confounders,most detected metals in immune cells were inversely associated with the proportion of immune cells in semen samples(all p<0.05),indicating the adverse effects of exogenous metals on immune cells.The proportion of immune cells showed N-shaped,nonlinear associations with sperm concentration,total count,progressive motility,and total motility.Mediation analyses showed that the percentage of indirect effects of exogenous metals on sperm quality parameters via immune cells ranged from 15.11%to 54.29%.Overall,our findings unravel the indirect effects of exogenous metal exposure on male reproductive health via immune cells,contributing valuable insights into the complex interplay between environmental factors,immune cells,and human semen quality.
文摘The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.
文摘This paper deals with the singular chemotaxis-Navier-Stokes system with indirect signal consumption n_(t)+u·▽v=△n-Х▽·(n/v▽u);v_(t)+u·▽v=△v-uw;w_(t)+u·▽w=△w-w+n;u_(t)+(u·▽)u=△u-▽P+n▽Ф;▽·u=0,x∈Ω,t>0 in a bounded and smooth domainΩ⊂ℝ2 with no-flux/no-flux/no-flux/no-slip boundary conditions,whereΦ∈W2,∞(Ω).A recent literature[Dai F,Liu B.J Differential Equations,2023,369:115–155]has proved that for all reasonably regular initial data,the associated initial-boundary value problem possesses a global classical solution,but qualitative information on the behavior of solution has never been touched so far.In stark contrast to the positive effect of indirect signal consumption mechanism on the global solvability of system,the analysis of asymptotic behavior of solution to the system with indirect signal consumption is essentially complicated than that with direct signal consumption because the favorable coupled structure between cells and signal is broken down by the indirect signal consumption mechanism.The present study shows that the global classical solution exponentially stabilizes toward the corresponding spatially homogeneous equilibria under a smallness condition on the initial cell mass.In comparison to the previously known result concerning the uniform convergence of solution to the system with direct signal consumption,our result inter alia provides a more in-depth understanding on the asymptotic behavior of solution.
基金supported by the Stanford Graduate Fellowship,the Center for Urban Science and Progress at New York Universitythe National Science Foundation under award number CMMI-2053014.The views and opinions expressed in this paper are those of the authors alone.
文摘Interdependencies between critical infrastructures and the economy amplify the effects of damage caused by disasters.The growing interest in impacts beyond physical damage and community resilience has spurred a surge in literature on economic modeling methodologies for estimating indirect economic impacts of disasters and the recovery of economic activity over time.In this review,we present a framework for categorizing modeling approaches that assess indirect economic impacts across natural hazards and anthropogenic disasters such as cyber attacks.We first conduct a comparative analysis of macroeconomic models,focusing on the approaches capturing sectoral interdependencies.These include the Leontief Input-Output(I/O)model,the Inoperability Input-Output Model(IIM),the Dynamic Inoperability Input-Output Model(DIIM),the Adaptive Regional Input-Output(ARIO)model,and the Computable General Equilibrium(CGE)model and its extensions.We evaluate their applicability to disaster scenarios based on input data availability,the compatibility of model assumptions,and output capabilities.We also reveal the functional relationships of input data and output metrics across economic modeling approaches for inter-sectoral impacts.Furthermore,we examine how the damage mechanisms posed by different types of disasters translate into model inputs and impact modeling processes.This synthesis provides guidance for researchers and practitioners in selecting and configuring models based on specific disaster scenarios.It also identifies the gaps in the literature,including the need for a deeper understanding of model performance reliability,key drivers of economic outcomes in different disaster contexts,and the disparities in modeling approach applications across various hazard types.
基金Supported by Natural Science Foundation of Shaanxi Province,No.2024JC-YBQN-0828 and No.2024JC-YBMS-765Clinical Research Award of the First Affiliated Hospital of Xi'an Jiaotong University,No.XJTU1AF-CRF-2022-036National Innovation Center for Advanced Medical Devices,No.NMED2023AGP-013.
文摘BACKGROUND Diabetic retinopathy(DR)is a major cause of visual impairment and blindness.However,the current DR biomarkers are insufficient for accurately predicting its onset.AIM To identify a novel marker for predicting the risk of developing DR in patients with type 2 diabetes mellitus(T2DM).METHODS We conducted a cross-sectional study involving 6993 hospitalized T2DM patients between 2013 and 2020.Patients were divided into two groups:The DR group and the non-DR group.Data were analyzed using univariate,correlation,multivariate,subgroup,and receiver operating characteristic curve analyses.RESULTS Total bilirubin,indirect bilirubin(IBIL),and direct bilirubin were negatively correlated with the risk of developing DR(P<0.001).Moreover,these three factors were all positively correlated with clinical indicators related to DR,including the estimated glomerular filtration rate,the albumin/creatinine ratio,and the 1,25-dihydroxyvitamin D3 level(P<0.001).After adjusting for multiple variables,greater IBIL levels remained independently associated with a lower risk of developing DR(odds ratio=0.500;95%confidence interval:0.363-0.686;P<0.001).The optimal IBIL cutoff point for predicting the risk of DR in male patients with elevated diastolic blood pressure was 0.655μmol/dL(area under the curve=0.662).CONCLUSION These findings suggest that IBIL could be a valuable biomarker for predicting DR risk,offering a noninvasive,cost-effective,and readily available clinical tool for the early identification of high-risk patients.Future multicenter and longitudinal studies are warranted to validate these findings and further explore the biological mechanisms underlying the protective role of IBIL in DR.
基金supported by the National Key Research and Development Program of China(No.2019YFA0110600)the Science and Technology Support Program of Sichuan Province(No.2019YJ0161).
文摘Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.
文摘Uniaxial compressive strength(UCS)is a significant mechanical measure in rock engineering,key for classifying rock masses,conducting stability assessments,and guiding design processes.Over the past five decades,numerous techniques and devices have emerged for UCS measurement.This paper presents a comprehensive literature review of existing methodologies and advancements in UCS testing,examining the theoretical foundations,testing equipment,data processing techniques,and criteria for selecting appropriate UCS testing methods.Additionally,the study highlights a shift toward automated,precise,and computational approaches with multiple inputs(i.e.multiple regression,machine learning,ML)for UCS prediction.Approximately 221 articles published by various researchers between 2000 and 2024 related to ML were reviewed,focusing on the application of ML models,including artificial neural networks(ANNs),adaptive-network-based fuzzy inference system(ANFIS),random forest(RF),support vector machine(SVM),and extreme gradient boosting(XGBoost),in UCS prediction.The review also observed the growing use of hybrid models integrating ML with optimization techniques,significantly improving UCS estimation.Numerous empirical correlations,both direct and indirect,have been established in the past several years based on the physical properties of rocks.However,utilizing these proposed equations to reliably estimate UCS remains challenging due to the variability in lithology,rock origin,and other factors.This study systematically presents the established correlation expressions,considering their lithology,the number of samples used to establish the expressions,the coefficient of determination(R^(2)),and the locations.This allows geologists and engineers to easily apply these established expressions in situations where direct estimation is not possible,enabling them to approximate UCS results.
基金Supported by the Startup Fund for Scientific Research,Fujian Medical University,No.2021QH1262.
文摘BACKGROUND Routinely separating the ligamentum teres uteri(LTU)intraoperatively remains an unresolved issue for female children undergoing surgery for indirect inguinal hernia(IIH).AIM To identify the effect of LTU preservation in laparoscopic high hernia sac ligation(LHSL)in children with IIH.METHODS The participants were 100 female children with unilateral IIH admitted from April 2022 to January 2024 to the Pediatric Surgery Department of Zhangzhou Municipal Hospital of Fujian Province.They were categorized based on LTU retention into the control group(n=45 cases),which underwent LTU ligation intraoperatively,and the experimental group(55 cases),which had the LTU preserved intraoperatively.All children underwent LHSL.RESULTS This study comparatively analyzed the operation time,hospitalization time,blood loss,postoperative recurrence rate,and complications(repeated pain in the inguinal region,foreign body sensation in the inguinal region,bloody exudation at the inguinal incision,and incision infection),which were all comparable between the two groups.CONCLUSION The above results indicate that LTU preservation during LHSL exerts certain therapeutic benefits for children with IIH.LTU preservation does not increase hospitalization time,blood loss,postoperative recurrence rate,and complications,which is safe and feasible,compared with conventional LTU ligation.LHSL with LTU preservation should be performed if conditions permit,which is worth popularizing.
文摘The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.
基金National Key Research and Development Program of China(2024YFB4610803)。
文摘The fatigue crack growth rate of a novel Ti-6Al-4V-1Mo titanium alloy,which is developed for laser directed energy deposition technique,was investigated before and after cyclic heat treatment(CHT).Changes in microstructure,fracture surfaces,and crack growth paths were analyzed before and after CHT.Results indicate that in the stable crack growth region,the growth rates for the as-deposited and cyclic heat-treated specimens follow the relationships da/dN=1.8651×10^(−8)(ΔK)^(3.2271)and da/dN=1.4112×10^(−8)(ΔK)^(3.1125),respectively.Compared with that at the as-deposited state,the microstructure after CHT is transformed from a uniform basket-weave microstructure to a dual-phase microstructure consisting of near-sphericalαandβ-transformed matrix phases.The cyclic process also disrupts the continuity of the grain boundaryα(αGB)at the primaryβ-phase grain boundary.The coarsening of primaryαand the disruption ofαGB continuity are the primary factors to release stress concentration and promote crack deflection,thereby decreasing the fatigue crack growth rate.Additionally,the increased occurrence of crack branching,secondary cracking,and crack bridging in cyclic heat-treated specimens further reduces the crack driving force and slows the fatigue crack growth rate.
基金financially supported by the National Natural Science Foundation of China(Nos.22475057 and No.52373262).
文摘Directional three-dimensional carbon-based foams are emerging as highly attractive candidates for promising electromagnetic wave absorbing materials(EWAMs)thanks to their unique architecture,but their construction usually involves complex procedures and extremely depends on unidirectional freezing technique.Herein,we propose a groundbreaking approach that leverages the assemblies of salting-out protein induced by ammonium metatungstate(AM)as the precursor,and then acquire directional three-dimensional carbon-based foams through simple pyrolysis.The electrostatic interaction between AM and protein ensures well dispersion of WC_(1−x)nanoparticles on carbon frameworks.The content of WC_(1−x)nanoparticles can be rationally regulated by AM dosage,and it also affects the electromagnetic(EM)properties of final carbon-based foams.The optimized foam exhibits exceptional EM absorption performance,achieving a remarkable minimum reflection loss of−72.0 dB and an effective absorption bandwidth of 6.3 GHz when EM wave propagates parallel to the directional pores.Such performance benefits from the synergistic effects of macroporous architecture and compositional design.Although there is a directional dependence of EM absorption,radar stealth simulation demonstrates that these foams can still promise considerable reduction in radar cross section with the change of incident angle.Moreover,COMSOL simulation further identifies their good performance in preventing EM interference among different electronic components.
基金supported in part by the National Key R&D Program of China(No.2024YFA1610700)the National Natural Science Foundation of China(No.12475147)。
文摘The Cooling-Storage-Ring External-target Experiment(CEE)at the Heavy Ion Research Facility in Lanzhou(HIRFL)is designed to study the properties of nuclear matter created in heavy-ion collisions at beam energies from a few hundred MeV/u up to 1 GeV/u.It aims to facilitate research on the quantum chromodynamics(QCD)phase structure in the high-baryondensity region.Collective flow is a fundamental observable in heavy-ion collision experiments,providing information on the bulk properties of the produced matter.Although the standard event plane method has been widely used to measure collective flow,it is still important to validate and optimize this method for the CEE spectrometer.In this paper,we study the experimental procedures for measuring directed flow in^(238)U+^(238)U collisions at 500 MeV/u,using event planes reconstructed by Multi-Wire Drift Chamber and Zero Degree Calorimeter,respectively.Jet AA Microscopic(JAM)transport generator is used to generate events,and the detector response is simulated by the CEE Fast Simulation(CFS)package.Finally,the optimal kinematic region for proton directed flow measurements is discussed for the future CEE experiment.
基金supported by the National Science Fund for Distinguished Young Scholars(52425706)。
文摘The rapid expansion of lithium-ion batteries in electric vehicles and grid-scale energy storage intensify the demand for sustainable recycling strategies.Traditional metallurgical recycling methods face significant challenges,including high energy consumption,environmental pollution,and inefficient critical metals recovery.In contrast,advanced direct recycling can selectively extract valuable metals while preserving cathode structure,achieving over 99%lithium recovery from lithium iron phosphate.Moreover,by directly repairing defects and crystal structures of spent materials,their electrochemical performance can be effectively restored.Due to significantly reduced energy and reagent inputs,direct recycling cuts processing costs by over 20% and reduces waste emissions by at least 40% compared to conventional methods,making it a promising low-carbon alternative.This review systematically integrates the recent advances in direct recycling of spent batteries as well as the limitations and challenges of existing technologies,and proposes future research pathways to promote resource recycling and sustainable development.
基金supported by the National Nature Science Foundation of China(Grant Nos.12475019 and 12073056)the Major National Science and Technology Project of China(Grant No.BX2024B054)+1 种基金National Lab of Solid State Microstructure of Nanjing University(Grant Nos.M35040,M35053,and M37014)the Natural Science Foundation of Shandong Province(Grant No.ZR2024MA038)。
文摘For a multi-frequency non-reciprocal optical device,we first realize multi-frequency optical non-reciprocal transmission using a non-Hermitian multi-mode resonator array.Practically,multi-frequency operation can add channels to the non-reciprocal optical device and the non-reciprocity can route optical signals and prevent the reverse flow of noise.Using the Scully–Lamb model and gain saturation effect,we accomplish dual-frequency non-reciprocal transmission by introducing nonlinearity into a linear array of four-mode resonators.The accomplishment is directly demonstrated by the non-reciprocal transmission phenomena present in the non-divergent peaks.For example,a directional cyclic amplifier is constructed with non-reciprocal units.Regarding potential applications,non-reciprocal optical systems can be employed in dual-frequency control,parallel information processing,photonic integrated circuits,optical devices and so on.
文摘Objective:To explore the interventional room nursing and its application effects in patients with ischemic stroke treated with tirofiban combined with direct thrombectomy.Methods:A total of 61 patients with ischemic stroke admitted to our hospital from June 2024 to June 2025 were selected and divided into two groups using the red and blue ball method:the control group(n=30,receiving routine interventional room nursing)and the observation group(n=31,receiving additional tirofiban medication-specific nursing+individualized interventional nursing on the basis of routine nursing).The cerebral hemodynamic indicators,adverse reactions,effectiveness of complication nursing,and nursing satisfaction were compared between the two groups.Results:After 7 days of treatment,the observation group had lower cerebrovascular peripheral resistance and higher mean blood flow velocity and mean blood flow volume compared to the control group(all p<0.05).The observation group had a higher effectiveness rate of complication nursing than the control group,with a statistically significant difference(p<0.05).The nursing satisfaction in the observation group(96.77%)was higher than that in the control group(80.00%),with a statistically significant difference(χ^(2)=4.223,p=0.040<0.05).Conclusion:Tirofiban combined with direct thrombectomy can significantly improve cerebral hemodynamics,enhance the effectiveness of complication nursing,and increase patient satisfaction in patients with ischemic stroke.
文摘BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Research in developing nations relating to the cost of treatment is scarce when compared with developed countries.Thus,the drug utilization research studies from developing nations are most needed,and their number has been growing.AIM To evaluate patterns of utilization of antipsychotic drugs and direct medical cost analysis in patients newly diagnosed with schizophrenia.METHODS The present study was observational in type and based on a retrospective cohort to evaluate patterns of utilization of antipsychotic drugs using World Health Organization(WHO)core prescribing indicators and anatomical therapeutic chemical/defined daily dose indicators.We also calculated direct medical costs for a period of 6 months.RESULTS This study has found that atypical antipsychotics are the mainstay of treatment for schizophrenia in every age group and subcategories of schizophrenia.The evaluation based on WHO prescribing indicators showed a low average number of drugs per prescription and low prescribing frequency of antipsychotics from the National List of Essential Medicines 2015 and the WHO Essential Medicines List 2019.The total mean drug cost of our study was 1396 Indian rupees.The total mean cost due to the investigation in our study was 1017.34 Indian rupees.Therefore,the total mean direct medical cost incurred on patients in our study was 4337.28 Indian rupees.CONCLUSION The information from the present study can be used for reviewing and updating treatment policy at the institutional level.
基金supported in part by the National Natural Science Foundation of China under Grants 62025110,62271093sponsored by Natural Science Foundation of Chongqing,China,under Grant CSTB2023NSCQ-LZX0108.
文摘Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.
