Many architectural research studies have focused on creating new materials to reduce the exploitation of non-renewable natural resources,achieve sustainable development,and reduce carbon emissions.Desert sand(DS)has a...Many architectural research studies have focused on creating new materials to reduce the exploitation of non-renewable natural resources,achieve sustainable development,and reduce carbon emissions.Desert sand(DS)has attracted interest from researchers who have conducted numerous experimental investigations as a possible replacement for river sand.The idea of utilising DS in place of natural fine aggregates in construction has been demonstrated in the literature.However,to analyse and gain confidence in using DS in concrete,a thorough study of its various properties is needed.Therefore,this study addresses the morphological,chemical,and physical characteristics of DS from multiple perspectives.This review presents a study on the durability of desert sand concrete(DSC)and the use of DS cement-based products,and highlights investigations on the design of mix proportions and fresh and hardened properties of DSC.Research issues are emerging around the use of DS in engineered cementitious composites(ECC)materials and the investigation of desert sand powder(DSP)as mineral admixtures.Many issues need to be resolved quickly,which is crucial for the use of DS.In summary,research on DS is still in its early stages,and no systematic research results have been obtained at present.This review makes several recommendations and attempts to explain why DS will likely be widely used as a building material in the future.展开更多
After the end of World War II,African countries successively gained independence and ushered in a golden age of economic development.Through the strategies of primary product exports,transitional economic policies and...After the end of World War II,African countries successively gained independence and ushered in a golden age of economic development.Through the strategies of primary product exports,transitional economic policies and import substitution development,their economic growth accelerated significantly.However,due to the limitations of these strategies,the structural problem of Africa being an exporter of cheap industrial raw materials and an importer of manufactured goods remained unresolved.展开更多
Elliptic curve(EC)based cryptosystems gained more attention due to enhanced security than the existing public key cryptosystems.A substitution box(S-box)plays a vital role in securing modern symmetric key cryptosystem...Elliptic curve(EC)based cryptosystems gained more attention due to enhanced security than the existing public key cryptosystems.A substitution box(S-box)plays a vital role in securing modern symmetric key cryptosystems.However,the recently developed EC based algorithms usually trade off between computational efficiency and security,necessitating the design of a new algorithm with the desired cryptographic strength.To address these shortcomings,this paper proposes a new scheme based onMordell elliptic curve(MEC)over the complex field for generating distinct,dynamic,and highly uncorrelated S-boxes.Furthermore,we count the exact number of the obtained S-boxes,and demonstrate that the permuted version of the presented S-box is statistically optimal.The nonsingularity of the presented algorithm and the injectivity of the resultant output are explored.Rigorous theoretical analysis and experimental results demonstrate that the proposedmethod is highly effective in generating a large number of dynamic S-boxes with adequate cryptographic properties,surpassing current state-of-the-art S-box generation algorithms in terms of security.Apart fromthis,the generated S-box is benchmarked using side-channel attacks,and its performance is compared with highly nonlinear S-boxes,demonstrating comparable results.In addition,we present an application of our proposed S-box generator by incorporating it into an image encryption technique.The encrypted and decrypted images are tested by employing extensive standard security metrics,including the Number of Pixel Change Rate,the Unified Average Changing Intensity,information entropy,correlation coefficient,and histogram analysis.Moreover,the analysis is extended beyond conventional metrics to validate the new method using advanced tests,such as the NIST statistical test suite,robustness analysis,and noise and cropping attacks.Experimental outcomes show that the presented algorithm strengthens the existing encryption scheme against various well-known cryptographic attacks.展开更多
The advancement of effective and stable non-precious metal-based catalysts for oxygen evolution reactions(OER)with a lowcost and simple technique is essential for the practical application of rechargeable zinc–air ba...The advancement of effective and stable non-precious metal-based catalysts for oxygen evolution reactions(OER)with a lowcost and simple technique is essential for the practical application of rechargeable zinc–air battery(ZAB).However,facilitating the deep reconstruction of electrocatalysts to form active species remains a significant challenge.Here,a simple two-step method composed of impregnation and carbonization process is proposed to synthesize N,S co-doped microcrystalline cellulose-derived carbon-supported nickel sulfide(Ni_(3)S_(2))nanoparticles.The in situ Raman reveals that Fe substitution promotes the reconstruction of Ni_(3)S_(2),accompanied by the cleavage of the Ni–S bond,leading to the deep reconstruction into(Ni,Fe)OOH(DR-(Ni,Fe)OOH)during the OER.Moreover,density functional theory calculations reveal that Fe substitution induces a downshift in the energy band structure,which lowers the energy barriers and thereby improves the kinetics of the OER.The generated DR-(Ni,Fe)OOH delivers a relatively low overpotential of 260 m V and superior durability for 50 h under OER condition.The ZAB incorporating DR-(Ni,Fe)OOH+Pt/C as the air cathode demonstrates superior efficiency and durability,achieving a peak power density of 188.3 m W cm^(-2),a specific capacity of 811.1 m Ah g^(-1),and long-term stability exceeding 200 h.展开更多
Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for ...Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.展开更多
Thinopyrum ponticum(2n=10×=70),a wild relative of common wheat(Triticum aestivum L.),is considered an invaluable genetic resource for wheat improvement due to its abundance of genes conferring resistance to bioti...Thinopyrum ponticum(2n=10×=70),a wild relative of common wheat(Triticum aestivum L.),is considered an invaluable genetic resource for wheat improvement due to its abundance of genes conferring resistance to biotic and abiotic stresses.This study focused on the CH97 line,derived from the BC1F7 progeny of a cross between wheat cv.7182 and Th.ponticum.Cytological evidence showed that CH97 has 42 chromosomes,forming 21 bivalents at meiotic metaphase I,with the bivalents subsequently separating and moving to opposite poles during meiotic anaphase I.Through a combination of fluorescence in situ hybridization(FISH),genomic in situ hybridization(GISH),multicolor GISH(mc-GISH),and liquid array analysis,it was determined that CH97 comprises 40 wheat chromosomes and two alien chromosomes from the Ee genome of Th.ponticum,featuring the absence of a pair of 5D chromosomes and variations in 1B,6B,and 7B chromosomes.These findings confirm that CH97 is a stable wheat-Th.ponticum 5E(5D)alien disomic substitution line.Inoculation experiments revealed that CH97 exhibits high resistance to wheat powdery mildew and stripe rust throughout the growth period,in contrast to the highly susceptible common wheat parent 7182.Compared to 7182,CH97 displayed improvements in thousand-kernel weight and kernel length.Additionally,utilizing specific-locus amplified fragment sequencing(SLAF-seq)technology,chromosome 5E-specific molecular markers were developed and validated,achieving a 33.3% success rate,facilitating marker-assisted selection for disease resistance in wheat.Overall,the CH97 substitution line,with its resistance to diseases and improved agronomic traits,represents valuable new germplasm for wheat chromosome engineering and breeding.展开更多
Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid com...Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid composition.We therefore designed a human milk phospholipid substitute(HMPS),and investigated its nutritional outcomes on brain development using C57BL/6J mice.Results showed that HMPS improved mice's cognitive behavior and dendritic development compared to soybean phospholipids and nophospholipid diets.Based on the lipidomics,we revealed that these beneficial outcomes were potentially associated with the increased biosynthesis of N-acylethanolamines,phosphatidylethanolamine(PE),and ether PE,and the decreased metabolism of diacylglycerol and hexosylceramide in brain.It was further found in Kyoto Encyclopedia of Genes and Genomes analysis that glycerophospholipid metabolic pathway participated in the improvement of HMPS on mice's neurodevelopment.In conclusion,this study demonstrated that HMPS improves mice's neurodevelopment,and the glycerophospholipid metabolic pathway plays a major role in this beneficial result,and provided evidence for future application of HMPS in commercial IF.展开更多
Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.C...Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.展开更多
Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on ...Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.展开更多
Weakly solvating electrolytes(WSEs)promote the formation of anion-driven solid electrolyte interphases(SEI),enabling stable lithium metal batteries.However,current strategies involving alkylated modification,steric hi...Weakly solvating electrolytes(WSEs)promote the formation of anion-driven solid electrolyte interphases(SEI),enabling stable lithium metal batteries.However,current strategies involving alkylated modification,steric hindrance incorporation,coordinated oxygen(O)regulation,and selective fluorination face poor-diversity interfacial chemistry,high cost,or environmental concerns.Here,we propose a heteroatom-substitution strategy to design a WSE composed of lithium bis(fluorosulfonyl)imide(LiFSI)and 1,4-oxathiane(OTA)as a single solvent.Substituting oxygen with sulfur in conventional 1,4-dioxane(1,4-DX)generates OTA with a modulated dipole and charge distribution,weakening Li^(+)-OTA coordination while promoting anion-involved solvation sheath.This unique solvation structure triggers the formation of an inorganic-rich SEI with sulfur-containing species,enabling high Li plating/stripping coulombic efficiency and stable Li‖Li symmetric cells cycling for 1000 h.Benefiting from the superior interfacial chemistry and wettability of the electrolyte to the LiFePO_(4) cathode,full cells exhibit exceptional cycling stability even at low negative-to-positive(N/P)ratios,A pouch cell coupled with3.58 mAh cm^(-2) LiFePO_(4) and 20μm Li(N/P~1.15)maintains 88.77%capacity after 150 cycles.This work shows a fluorine-free solvent design paradigm for advanced WSEs,providing novel insights toward stable LMBs.展开更多
The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its prope...The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its properties,hydrostatic pressure provides a disorder-free route to manipulate electronic and magnetic interactions.Herein,we investigate the effects of hydrostatic pressure on electrical and magneto-transport in TbMn6Sn6 up to 18.3 GPa.Pressure significantly enhances hysteresis in the magnetoresistance and Hall responses,causing a concurrent monotonic coercive field increase,suggesting the enhancement of interlayer magnetic couplings in a robust c-axis ferrimagnetic order.The intrinsic anomalous Hall conductivity increases considerably from 129.5 S·cm^(−1) at ambient pressure conditions to 448.7 S·cm^(−1) at 14.0 GPa—an enhancement of 247%that is unprecedented among pressure-tuned kagome magnets.Based on density functional theory calculations,we reveal that pressure induces multiple gap openings near the Fermi level,giving rise to pronounced Berry curvature hotspots that may contribute to the AHE.Our results show that pressure can be used to enhance the intrinsic topological responses of this kagome magnet.展开更多
Benzoic acid containing fluorine atom at ortho-,meta-,and para-position are employed as self-assembled monolayers to modify the buried interface in perovskite solar cells(PSCs).It is demonstrated that the position of ...Benzoic acid containing fluorine atom at ortho-,meta-,and para-position are employed as self-assembled monolayers to modify the buried interface in perovskite solar cells(PSCs).It is demonstrated that the position of fluorine atom influences the passivation effect and para-fluorinated one provided the most substantial performance enhancement mainly originating from ameliorated contact and energy band alignment between NiOx and perovskite,improved perovskite quality and defect healing.Resultantly,PSC with a power conversion efficiency of 24%can be achieved.Meanwhile,which can maintain 96.8%of the initial PCE after a 1000 h storage,presenting enhanced durability.This work highlights the critical role of molecular functionality and conformation in the buried interface modification of PSCs,providing valuable insights for future developments.展开更多
The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combin...The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combination of density functional theory and dynamical mean-field theory(DFT+DMFT)to systematically investigate the evolution of electronic correlations in the CsV_(3−x)Cr_(x)Sb_(5)(x=0,1,and 3)series.Our calculations revealed that Cr doping drives the system into a strongly correlated Hund’s metal phase,which is characterized by significant and orbital-dependent enhancements in the quasiparticle effective masses and electronic scattering rates.We trace the origin of this transition to the doping-induced shift from low-to high-spin atomic configurations.This preference for high-spin states,which is promoted by near-half-filling of the Cr-d orbitals,induces a pronounced orbital blocking effect that strengthens the correlations.Our findings establish that Hund’s coupling is the decisive factor governing the rich correlation physics in the CsV_(3−x)Cr_(x)Sb_(5) family,providing a tunable platform for exploring Hund’s metallicity.展开更多
The relationship between ecosystem services(ES)and human well-being(HWB)is fundamental to the science and practice of sustainability.However,studies have shown conflicting results,which has been attributed to the infl...The relationship between ecosystem services(ES)and human well-being(HWB)is fundamental to the science and practice of sustainability.However,studies have shown conflicting results,which has been attributed to the influences of indicators,contexts,and scales.Yet,another potential factor,which has been overlooked,may be the mixed use of spatial and temporal approaches.Using twelve ES and seven well-being indicators and multiple statistical methods,we quantified and compared the spatial and temporal ES–HWB relationships for Inner Mongolia,China.The spatial and temporal relationships differed in both correlation direction and strength.Most relationships of economic and employment-related indicators with food provisioning and supporting services were temporally positive but spatially nonsignificant or negative.Some relationships of economic and employmentrelated indicators with water retention,sandstorm prevention,and wind erosion were temporally negative but spatially complex.However,the spatial and temporal ES–HWB relationships could also be similar in some cases.We conclude that although both the spatial and temporal approaches have merits,space generally cannot substitute for time in the study of ES–HWB relationship.Our study helps reconcile the seemingly conflicting findings in the literature,and suggests that future studies should explicitly distinguish between the spatial and temporal ES–HWB relationships.展开更多
A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,whic...A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.展开更多
The practical application of aqueous zinc-ion batteries(AZIBs)is primarily constrained by issues such as corrosion,zinc dendrite formation,and the hydrogen evolution reaction occurring at the zinc metal anode.To overc...The practical application of aqueous zinc-ion batteries(AZIBs)is primarily constrained by issues such as corrosion,zinc dendrite formation,and the hydrogen evolution reaction occurring at the zinc metal anode.To overcome these challenges,strategies for optimizing the electrolyte are crucial for enhancing the stability of the zinc anode.Inspired by the role of hemoglobin in blood cells,which facilitates oxygen transport during human respiration,an innovative inorganic colloidal electrolyte has been developed:calcium silicate-ZnSO_(4)(denoted as CS-ZSO).This electrolyte operates in weak acidic environment and releases calcium ions,which participate in homotopic substitution with zinc ions,while the solvation environment of hydrated zinc ions in the electrolyte is regulated.The reduced energy barrier for the transfer of zinc ions and the energy barrier for the desolvation of hydrated ions imply faster ion transfer kinetics and accelerated desolvation processes,thus favoring the mass transfer process.Furthermore,the silicate colloidal particles act as lubricants,improving the transfer of zinc ions.Together,these factors contribute to the more uniform concentration of zinc ions at the electrode/electrolyte interface,effectively inhibiting zinc dendrite formation and reducing by-product accumulation.The Zn//CS-ZSO//Zn symmetric cell demonstrates stable operation for over 5000 h at 1 mA cm^(-2),representing 29-fold improvement compared to the Zn//ZSO//Zn symmetric cell,which lasts only 170 h.Additionally,the Zn//CS-ZSO//Cu asymmetric cell shows stable average Coulombic efficiency(CE)exceeding 99.6%over2400 cycles,significantly surpassing the performance of the ZSO electrolyte.This modification strategy for electrolytes not only addresses key limitations associated with zinc anodes but also provides valuable insights into stabilizing anodes for the advancement of high-performance aqueous zinc-ion energy storage systems.展开更多
Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,...Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.展开更多
Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials ...Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.展开更多
Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N c...Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N catalysis.Monosubstitu-tion C—N bond formation reaction catalyzed by K_(2)CO_(3) also gave novel enol-based target products.This method is simple and mild,with good chemoselectivity,excellent substrate compatibility and tolerance for various functional groups,and achieves gram-scale synthesis.The reaction is a nucleophilic substitution process without the involvement of free radicals.展开更多
文摘Many architectural research studies have focused on creating new materials to reduce the exploitation of non-renewable natural resources,achieve sustainable development,and reduce carbon emissions.Desert sand(DS)has attracted interest from researchers who have conducted numerous experimental investigations as a possible replacement for river sand.The idea of utilising DS in place of natural fine aggregates in construction has been demonstrated in the literature.However,to analyse and gain confidence in using DS in concrete,a thorough study of its various properties is needed.Therefore,this study addresses the morphological,chemical,and physical characteristics of DS from multiple perspectives.This review presents a study on the durability of desert sand concrete(DSC)and the use of DS cement-based products,and highlights investigations on the design of mix proportions and fresh and hardened properties of DSC.Research issues are emerging around the use of DS in engineered cementitious composites(ECC)materials and the investigation of desert sand powder(DSP)as mineral admixtures.Many issues need to be resolved quickly,which is crucial for the use of DS.In summary,research on DS is still in its early stages,and no systematic research results have been obtained at present.This review makes several recommendations and attempts to explain why DS will likely be widely used as a building material in the future.
文摘After the end of World War II,African countries successively gained independence and ushered in a golden age of economic development.Through the strategies of primary product exports,transitional economic policies and import substitution development,their economic growth accelerated significantly.However,due to the limitations of these strategies,the structural problem of Africa being an exporter of cheap industrial raw materials and an importer of manufactured goods remained unresolved.
文摘Elliptic curve(EC)based cryptosystems gained more attention due to enhanced security than the existing public key cryptosystems.A substitution box(S-box)plays a vital role in securing modern symmetric key cryptosystems.However,the recently developed EC based algorithms usually trade off between computational efficiency and security,necessitating the design of a new algorithm with the desired cryptographic strength.To address these shortcomings,this paper proposes a new scheme based onMordell elliptic curve(MEC)over the complex field for generating distinct,dynamic,and highly uncorrelated S-boxes.Furthermore,we count the exact number of the obtained S-boxes,and demonstrate that the permuted version of the presented S-box is statistically optimal.The nonsingularity of the presented algorithm and the injectivity of the resultant output are explored.Rigorous theoretical analysis and experimental results demonstrate that the proposedmethod is highly effective in generating a large number of dynamic S-boxes with adequate cryptographic properties,surpassing current state-of-the-art S-box generation algorithms in terms of security.Apart fromthis,the generated S-box is benchmarked using side-channel attacks,and its performance is compared with highly nonlinear S-boxes,demonstrating comparable results.In addition,we present an application of our proposed S-box generator by incorporating it into an image encryption technique.The encrypted and decrypted images are tested by employing extensive standard security metrics,including the Number of Pixel Change Rate,the Unified Average Changing Intensity,information entropy,correlation coefficient,and histogram analysis.Moreover,the analysis is extended beyond conventional metrics to validate the new method using advanced tests,such as the NIST statistical test suite,robustness analysis,and noise and cropping attacks.Experimental outcomes show that the presented algorithm strengthens the existing encryption scheme against various well-known cryptographic attacks.
基金financially supported by the National Natural Science Foundation of China(32301514)the Young Elite Scientist Sponsorship Program by CAST(YESS20220240)。
文摘The advancement of effective and stable non-precious metal-based catalysts for oxygen evolution reactions(OER)with a lowcost and simple technique is essential for the practical application of rechargeable zinc–air battery(ZAB).However,facilitating the deep reconstruction of electrocatalysts to form active species remains a significant challenge.Here,a simple two-step method composed of impregnation and carbonization process is proposed to synthesize N,S co-doped microcrystalline cellulose-derived carbon-supported nickel sulfide(Ni_(3)S_(2))nanoparticles.The in situ Raman reveals that Fe substitution promotes the reconstruction of Ni_(3)S_(2),accompanied by the cleavage of the Ni–S bond,leading to the deep reconstruction into(Ni,Fe)OOH(DR-(Ni,Fe)OOH)during the OER.Moreover,density functional theory calculations reveal that Fe substitution induces a downshift in the energy band structure,which lowers the energy barriers and thereby improves the kinetics of the OER.The generated DR-(Ni,Fe)OOH delivers a relatively low overpotential of 260 m V and superior durability for 50 h under OER condition.The ZAB incorporating DR-(Ni,Fe)OOH+Pt/C as the air cathode demonstrates superior efficiency and durability,achieving a peak power density of 188.3 m W cm^(-2),a specific capacity of 811.1 m Ah g^(-1),and long-term stability exceeding 200 h.
基金supported by the National Natural Science Foundation of China(Grant No.22175136)the State Key Laboratory of Electrical Insulation and Power Equipment(Grant No.EIPE23127)the Fundamental Research Funds for the Central Universities(xtr052024009,xtr052025002).
文摘Violet phosphorus,a recently explored layered elemental semiconductor,has attracted much attention due to its unique photoelectric,mechanical properties,and high hole mobility.Herein,violet arsenic phosphorus has for the first time been synthesized by a molten lead method.The crystal structure of violet arsenic phosphorus(P^(83.4)As_(0.6),CSD-2408761)was determined by single crystal X-ray diffraction to have similar structure as that of violet phosphorus,where P12 is occupied by arsenic/phosphorus(As/P)atoms as mixed occupancy sites As1/P12.The arsenic substitution has been demonstrated to tune the band structure of violet phosphorus,switching p-type of violet phosphorus to high-performance n-type violet arsenic phosphorus.The effective electron mass along the<010>direction is significantly reduced from 1.792 to 0.515 m_(0)by arsenic substitution,resulting in an extremely high electron mobility of 2622.503 cm^(2)V^(-1)s^(-1).The field effect transistor built with P_(83.4)As_(0.6)nanosheets was measured to have a high electron mobility(137.06 cm^(2)V^(-1)s^(-1),61.2 nm),even under ambient conditions for 5 h,much higher than the hole mobility of violet phosphorene nanosheets(4.07 cm^(2)V^(-1)s^(-1),73.3 nm).This work provides a new idea for designing phosphorus-based materials for field effect transistors,giving significant potential in complementary metal-oxide-semiconductor applications.
基金funded by the Key R&D Program of Yangling Seed Industry Innovation,China(Ylzy-xm-02)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2021QNRC001)。
文摘Thinopyrum ponticum(2n=10×=70),a wild relative of common wheat(Triticum aestivum L.),is considered an invaluable genetic resource for wheat improvement due to its abundance of genes conferring resistance to biotic and abiotic stresses.This study focused on the CH97 line,derived from the BC1F7 progeny of a cross between wheat cv.7182 and Th.ponticum.Cytological evidence showed that CH97 has 42 chromosomes,forming 21 bivalents at meiotic metaphase I,with the bivalents subsequently separating and moving to opposite poles during meiotic anaphase I.Through a combination of fluorescence in situ hybridization(FISH),genomic in situ hybridization(GISH),multicolor GISH(mc-GISH),and liquid array analysis,it was determined that CH97 comprises 40 wheat chromosomes and two alien chromosomes from the Ee genome of Th.ponticum,featuring the absence of a pair of 5D chromosomes and variations in 1B,6B,and 7B chromosomes.These findings confirm that CH97 is a stable wheat-Th.ponticum 5E(5D)alien disomic substitution line.Inoculation experiments revealed that CH97 exhibits high resistance to wheat powdery mildew and stripe rust throughout the growth period,in contrast to the highly susceptible common wheat parent 7182.Compared to 7182,CH97 displayed improvements in thousand-kernel weight and kernel length.Additionally,utilizing specific-locus amplified fragment sequencing(SLAF-seq)technology,chromosome 5E-specific molecular markers were developed and validated,achieving a 33.3% success rate,facilitating marker-assisted selection for disease resistance in wheat.Overall,the CH97 substitution line,with its resistance to diseases and improved agronomic traits,represents valuable new germplasm for wheat chromosome engineering and breeding.
基金supported by Huhhot Science&Technology Plan(2021-National Center of Technology innovation for Dairy-4)Innovation Consortium Project(2023RC Consortium-7)+3 种基金National Key Research and Development Program(2023YFF1104502)Ganpo Juncai supports the plan(20232BCJ22046)Nanchang University Jiangxi Financial Science and Technology Special Project(ZBG20230418011)Free Exploration Project of State Key Laboratory(SKLF-ZZB-202317).
文摘Although human milk fat substitute(HMFS)has been wildly applied in infant formula(IF),there are still some differences in fat composition between human milk and IF,which is extremely attributed to the phospholipid composition.We therefore designed a human milk phospholipid substitute(HMPS),and investigated its nutritional outcomes on brain development using C57BL/6J mice.Results showed that HMPS improved mice's cognitive behavior and dendritic development compared to soybean phospholipids and nophospholipid diets.Based on the lipidomics,we revealed that these beneficial outcomes were potentially associated with the increased biosynthesis of N-acylethanolamines,phosphatidylethanolamine(PE),and ether PE,and the decreased metabolism of diacylglycerol and hexosylceramide in brain.It was further found in Kyoto Encyclopedia of Genes and Genomes analysis that glycerophospholipid metabolic pathway participated in the improvement of HMPS on mice's neurodevelopment.In conclusion,this study demonstrated that HMPS improves mice's neurodevelopment,and the glycerophospholipid metabolic pathway plays a major role in this beneficial result,and provided evidence for future application of HMPS in commercial IF.
基金supported by the 2025 Jiangsu Province Graduate Student Practice Innovation Program(No.SJCX25_1696)the 2024 Changzhou University Educational Research Project(No.GJY2024009).
文摘Background:The phenomenon of multimorbidity in chronic diseases among the elderly is prevalent,and its significant association with depression poses a serious threat to the physical and mental health of older adults.Current research on the associations between 24-hour movement behaviors(including physical activity,sedentary behavior,and sleep)and depression has largely been confined to examining the effects of single behaviors,overlooking the intrinsic compositional nature and interrelationships among these behaviors.Therefore,it is necessary to investigate the integrated effects of 24-hour movement behaviors on depression in older adults with multimorbidity from a holistic,compositional perspective.Methods:From November 2024 to April 2025,a total of 226 older adult patients with multimorbidity were recruited from a tertiary hospital in Changzhou City.Data were collected using a general information questionnaire,the International Physical Activity Questionnaire–Short Form(IPAQ-SF),the Pittsburgh Sleep Quality Index(PSQI),and the Patient Health Questionnaire-9(PHQ-9).Compositional data analysis and isotemporal substitution models were employed for statistical analysis.Results:The mean daily durations of Light-Intensity Physical Activity(LPA),Moderate-to-Vigorous Physical Activity(MVPA),Sedentary Behavior(SB),and Sleep(SLP)in older adults with multimorbidity were 402.48 min,12.04 min,511.52 min,and 458.68 min,respectively.The prevalence of depressive symptoms was 37.6%.Compositional data analysis revealed that SB was positively associated with depression(βSB=1.005,P=0.006),while SLP was negatively associated with depression(βSLP=−1.736,P<0.001).No statistically significant associations were found between MVPA or LPA and depression(P>0.05).In the 10-minute isotemporal substitution model,replacing SB with any other behavioral component was associated with a decrease in depression scores.Conversely,substituting SLP with either LPA or SB resulted in an increase in depression scores,while substituting SLP with MVPA led to a decrease in depression scores.The dose-response analysis revealed that,among the isotemporal substitution effects,replacing SB with SLP and replacing SLP with MVPA were the substitution pathways associated with the most rapid decline in depression scores,representing the greatest beneficial health effects.Conclusion:The prevalence of depression is notably high among older adults with multimorbidity.Reducing daily sedentary behavior(SB),maintaining adequate sleep(SLP),and increasing moderate-to-vigorous physical activity(MVPA)can improve depressive symptoms and enhance overall health in this population.
基金supported by the Foundation of Yunnan Province(Nos.202301AU070021,202201BE070001-027)the Test Foundation of KUST(No.2022T20210208).
文摘Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.
基金the financial support from the National Natural Science Foundation of China,China(Grant Nos.52502258 and 52162030)the Yunnan Fundamental Research Projects,China(Grant Nos.202501AT070298,202401AU070163 and 202401AT070368)+5 种基金the Yunnan Engineering Research Center Innovation Ability Construction and Enhancement Projects,China(Grant No.2023-XMDJ-00617107)the Expert Workstation Support Project of Yunnan Province,China(Grant Nos.202405AF140069 and 202505AF350019)the University Service Key Industry Project of Yunnan Province,China(Grant No.FWCY-ZD2024005)the Shenzhen Science and Technology Program,China(Grant No.KJZD20230923114107014)the Scientific Research Foundation of Kunming University of Science and Technology,China(20220122)the Analysis and Test Foundation of Kunming University of Science and Technology,China(Grant No.2023T20220122)。
文摘Weakly solvating electrolytes(WSEs)promote the formation of anion-driven solid electrolyte interphases(SEI),enabling stable lithium metal batteries.However,current strategies involving alkylated modification,steric hindrance incorporation,coordinated oxygen(O)regulation,and selective fluorination face poor-diversity interfacial chemistry,high cost,or environmental concerns.Here,we propose a heteroatom-substitution strategy to design a WSE composed of lithium bis(fluorosulfonyl)imide(LiFSI)and 1,4-oxathiane(OTA)as a single solvent.Substituting oxygen with sulfur in conventional 1,4-dioxane(1,4-DX)generates OTA with a modulated dipole and charge distribution,weakening Li^(+)-OTA coordination while promoting anion-involved solvation sheath.This unique solvation structure triggers the formation of an inorganic-rich SEI with sulfur-containing species,enabling high Li plating/stripping coulombic efficiency and stable Li‖Li symmetric cells cycling for 1000 h.Benefiting from the superior interfacial chemistry and wettability of the electrolyte to the LiFePO_(4) cathode,full cells exhibit exceptional cycling stability even at low negative-to-positive(N/P)ratios,A pouch cell coupled with3.58 mAh cm^(-2) LiFePO_(4) and 20μm Li(N/P~1.15)maintains 88.77%capacity after 150 cycles.This work shows a fluorine-free solvent design paradigm for advanced WSEs,providing novel insights toward stable LMBs.
基金supported by the National Key R&D Program of China (Grant Nos.2023YFA1406002 and 2020YFA0308801)the National Natural Science Foundation of China (NSFC) (Grant Nos.12321004,12174025,12074041,and 12204045)+7 种基金the CAS Superconducting Research Project (Grant No.SCZX-0101)the Fundamental Research Funds for the Central Universities (Grant No.2243300003)the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0302800)supported by the Synergetic Extreme Condition User Facility (SECUF)Analysis & Testing center in Beijing Institute of Technologysupport from the Beijing Institute of Technology Research Fund Program (Grant No.2023CX01027)support from the Beijing Institute of Technology Research Fund Program for Young Scholarssupport from the Beijing Institute of Technology Laboratory Research Project (Grant No.2023BITSYB07)。
文摘The kagome ferrimagnet TbMn_(6)Sn_(6),featuring a pristine Mn kagome lattice,has emerged as a candidate Chern magnet with a large intrinsic anomalous Hall effect(AHE).While chemical substitution can modulate its properties,hydrostatic pressure provides a disorder-free route to manipulate electronic and magnetic interactions.Herein,we investigate the effects of hydrostatic pressure on electrical and magneto-transport in TbMn6Sn6 up to 18.3 GPa.Pressure significantly enhances hysteresis in the magnetoresistance and Hall responses,causing a concurrent monotonic coercive field increase,suggesting the enhancement of interlayer magnetic couplings in a robust c-axis ferrimagnetic order.The intrinsic anomalous Hall conductivity increases considerably from 129.5 S·cm^(−1) at ambient pressure conditions to 448.7 S·cm^(−1) at 14.0 GPa—an enhancement of 247%that is unprecedented among pressure-tuned kagome magnets.Based on density functional theory calculations,we reveal that pressure induces multiple gap openings near the Fermi level,giving rise to pronounced Berry curvature hotspots that may contribute to the AHE.Our results show that pressure can be used to enhance the intrinsic topological responses of this kagome magnet.
基金the Key project of Nature Science Foundation of Tianjin(22JCZDJC00120)the 111 Project(B16027)for financial support.
文摘Benzoic acid containing fluorine atom at ortho-,meta-,and para-position are employed as self-assembled monolayers to modify the buried interface in perovskite solar cells(PSCs).It is demonstrated that the position of fluorine atom influences the passivation effect and para-fluorinated one provided the most substantial performance enhancement mainly originating from ameliorated contact and energy band alignment between NiOx and perovskite,improved perovskite quality and defect healing.Resultantly,PSC with a power conversion efficiency of 24%can be achieved.Meanwhile,which can maintain 96.8%of the initial PCE after a 1000 h storage,presenting enhanced durability.This work highlights the critical role of molecular functionality and conformation in the buried interface modification of PSCs,providing valuable insights for future developments.
基金supported by the Development Program of China and the National Key Research (Grant Nos.2023YFA1406200 and 2022YFA1402304)the National Natural Science Foundation of China (Grant Nos.12274169 and 12122405)+3 种基金the Fundamental Research Funds for the Central Universitiesthe Innovation Team for Functional Materials and Devices for Informatics at Anhui Higher Education Institutes (Grant No.2024AH010024)the Natural Science Research Project of Education Department of Anhui Province (Grant No.2025AHGXZK31203)the PHD Research Startup Foundation of Fuyang Normal University (Grant No.2025KYQD0072)。
文摘The Kagome metal CsV3Sb5 transitions from a weakly correlated state to a strongly correlated state upon Cr substitution;however,the mechanism driving this enhancement remains an open question.Here,we employed a combination of density functional theory and dynamical mean-field theory(DFT+DMFT)to systematically investigate the evolution of electronic correlations in the CsV_(3−x)Cr_(x)Sb_(5)(x=0,1,and 3)series.Our calculations revealed that Cr doping drives the system into a strongly correlated Hund’s metal phase,which is characterized by significant and orbital-dependent enhancements in the quasiparticle effective masses and electronic scattering rates.We trace the origin of this transition to the doping-induced shift from low-to high-spin atomic configurations.This preference for high-spin states,which is promoted by near-half-filling of the Cr-d orbitals,induces a pronounced orbital blocking effect that strengthens the correlations.Our findings establish that Hund’s coupling is the decisive factor governing the rich correlation physics in the CsV_(3−x)Cr_(x)Sb_(5) family,providing a tunable platform for exploring Hund’s metallicity.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.B240201068)the National Natural Science Foundation of China(Grant No.42361144861)the National Basic Research Program of China(Grant No.2014CB954303).
文摘The relationship between ecosystem services(ES)and human well-being(HWB)is fundamental to the science and practice of sustainability.However,studies have shown conflicting results,which has been attributed to the influences of indicators,contexts,and scales.Yet,another potential factor,which has been overlooked,may be the mixed use of spatial and temporal approaches.Using twelve ES and seven well-being indicators and multiple statistical methods,we quantified and compared the spatial and temporal ES–HWB relationships for Inner Mongolia,China.The spatial and temporal relationships differed in both correlation direction and strength.Most relationships of economic and employment-related indicators with food provisioning and supporting services were temporally positive but spatially nonsignificant or negative.Some relationships of economic and employmentrelated indicators with water retention,sandstorm prevention,and wind erosion were temporally negative but spatially complex.However,the spatial and temporal ES–HWB relationships could also be similar in some cases.We conclude that although both the spatial and temporal approaches have merits,space generally cannot substitute for time in the study of ES–HWB relationship.Our study helps reconcile the seemingly conflicting findings in the literature,and suggests that future studies should explicitly distinguish between the spatial and temporal ES–HWB relationships.
文摘A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.
基金the Doctoral Research Start-up Fund of Hubei University of Science and Technology(BK202504)the Natural Science Foundation of Liaoning Province(2023-MS-115)。
文摘The practical application of aqueous zinc-ion batteries(AZIBs)is primarily constrained by issues such as corrosion,zinc dendrite formation,and the hydrogen evolution reaction occurring at the zinc metal anode.To overcome these challenges,strategies for optimizing the electrolyte are crucial for enhancing the stability of the zinc anode.Inspired by the role of hemoglobin in blood cells,which facilitates oxygen transport during human respiration,an innovative inorganic colloidal electrolyte has been developed:calcium silicate-ZnSO_(4)(denoted as CS-ZSO).This electrolyte operates in weak acidic environment and releases calcium ions,which participate in homotopic substitution with zinc ions,while the solvation environment of hydrated zinc ions in the electrolyte is regulated.The reduced energy barrier for the transfer of zinc ions and the energy barrier for the desolvation of hydrated ions imply faster ion transfer kinetics and accelerated desolvation processes,thus favoring the mass transfer process.Furthermore,the silicate colloidal particles act as lubricants,improving the transfer of zinc ions.Together,these factors contribute to the more uniform concentration of zinc ions at the electrode/electrolyte interface,effectively inhibiting zinc dendrite formation and reducing by-product accumulation.The Zn//CS-ZSO//Zn symmetric cell demonstrates stable operation for over 5000 h at 1 mA cm^(-2),representing 29-fold improvement compared to the Zn//ZSO//Zn symmetric cell,which lasts only 170 h.Additionally,the Zn//CS-ZSO//Cu asymmetric cell shows stable average Coulombic efficiency(CE)exceeding 99.6%over2400 cycles,significantly surpassing the performance of the ZSO electrolyte.This modification strategy for electrolytes not only addresses key limitations associated with zinc anodes but also provides valuable insights into stabilizing anodes for the advancement of high-performance aqueous zinc-ion energy storage systems.
基金supported by the National Key Research and Development Program of China(No.2022YFB3505301)the National Key Research and Development Program of Shanxi Province(No.202302050201014)+2 种基金the National Natural Science Foundation of China(No.12304148)the Natural Science Basic Research Program of Shanxi Province(No.202203021222219)the China Postdoctoral Science Foundation(No.2023M731452).
文摘Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.
基金financially supported by the Scientific and Technological Plan Project of Guizhou Province ([2024]054)Additional support came from the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University (2020-520000-83-01324061)the Guizhou Engineering Research Center for Smart Services (2203-520102-04-04-298868)。
文摘Aqueous sodium-ion batteries(ASIBs) offer significant advantages for energy storage on a large scale,attributed to their economical cost,secure operatio n,and eco-friend ly natu re.Among the leading cathode materials for ASIBs,Na_(3)V_(2)(PO_(4))_(3)(NVP) exhibits excellent structural stability and a high Na+diffusion coefficient,making it a promising option.However,the high solubility of vanadium-based materials in aqueous electrolytes engenders suboptimal cycling stability for Na_(3)V_(2)(PO_(4))_(3),constraining its application in ASIBs.Herein,the Cr-substituted Na_(3)V_(1.3)Cr_(0.7)(PO_(4))3@C(NV_(1.3)Cr_(0.7)P) cathode material was synthesized via a simple sol-gel method.It is found that Cr substitution reduces the cell parameters of NV_(1.3)Cr_(0.7)P,effectively reinforcing the crystal structure.Furthermore,NV_(1.3)Cr_(0.7)P alters the Na^(+)insertion/extraction mechanism,transforming the typical two-phase reaction between Na_(1)V_(2)(PO_(4))_(3)and Na_(3)V_(2)(PO_(4))3into continuous solid-solution reactions with stable intermediates.The Cr substitution diminishes the sodium-ion diffusion energy barrier in NV_(1.3)Cr_(0.7)P,leading to smoother Na+insertion and extraction processes.Consequently,NV_(1.3)Cr_(0.7)P exhibits impressive cycling stability,retaining 74.8% of its capacity after 5,000 cycles at a current density of 5 A g^(-1),along with an outstanding rate performance of 79,2% at 10 A g^(-1).This work elucidates the stable Na^(+)insertion/extraction processes in Cr-substituted NV_(1.3)Cr_(0.7)P,offering insights into the application of vanadium-based materials in aqueous sodium-ion batteries.
文摘Base-catalyzed nucleophilic substitution reactions ofβ-ketonitrile with azodicarboxylates have been developed.A series of disubstituted C—N coupling products were obtained in good to excellent yields under Et_(3)N catalysis.Monosubstitu-tion C—N bond formation reaction catalyzed by K_(2)CO_(3) also gave novel enol-based target products.This method is simple and mild,with good chemoselectivity,excellent substrate compatibility and tolerance for various functional groups,and achieves gram-scale synthesis.The reaction is a nucleophilic substitution process without the involvement of free radicals.
