The Li metal battery with ultrahigh-nickel cathode(LiNi_(x)M_(1-x)O_(2),M=Mn,Co,and x≥0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/kg.However,th...The Li metal battery with ultrahigh-nickel cathode(LiNi_(x)M_(1-x)O_(2),M=Mn,Co,and x≥0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/kg.However,the practical application is impeded by the instability of electrode/electrolyte interface and Ni-rich cathode itself.Herein we proposed an electron-defect electrolyte additive trimethyl borate(TMB)which is paired with the commercial carbonate electrolyte to construct highly conductive fluorine-and boron-rich cathode electrolyte interface(CEI)on LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)surface and solid electrolyte interphase(SEI)on lithium metal surface.The modified CEI effectively mitigates the structural transformation from layered to disordered rock-salt phase,and consequently alleviate the dissolution of transition metal ions(TMs)and its“cross-talk”effect,while the enhanced SEI enables stable lithium plating/striping and thus demonstrated good compatibility between electrolyte and lithium metal anode.As a result,the common electrolyte with 1 wt%TMB enables 4.7 V NCM90/Li cell cycle stably over 100 cycles with 70%capacity retention.This work highlights the significance of the electron-defect boron compounds for designing desirable interfacial chemistries to achieve high performance NCM90/Li battery under high voltage operation.展开更多
The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ab...The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.展开更多
Site disorder exists in some practical semiconductors and can significantly impact their intrinsic properties both beneficially and detrimentally.However,the uncertain local order and structure pose a challenge for ex...Site disorder exists in some practical semiconductors and can significantly impact their intrinsic properties both beneficially and detrimentally.However,the uncertain local order and structure pose a challenge for experimental and theoretical research.Especially,it hinders the investigation of the effects of the diverse local atomic environments resulting from the site disorder.We employ the special quasi-random structure method to perform first-principles research on connection between local site disorder and electronic/optical properties,using cationdisordered AgBiS_(2)(rock salt phase)as an example.We predict that cation-disordered AgBiS_(2)has a bandgap ranging from 0.6 to 0.8 eV without spin-orbit coupling and that spin-orbit coupling reduces this by approximately 0.3 eV.We observe the effects of local structural features in the disordered lattice,such as the one-dimensional chain-like aggregation of cations that results in formation of doping energy bands near the band edges,formation and broadening of band-tail states,and the disturbance in the local electrostatic potential,which significantly reduces the bandgap and stability.The influence of these ordered features on the optical properties is confined to alterations in the bandgap and does not markedly affect the joint density of states or optical absorption.Our study provides a research roadmap for exploring the electronic structure of site-disordered semiconductor materials,suggests that the ordered chain-like aggregation of cations is an effective way to regulate the bandgap of AgBiS_(2),and provides insight into how variations in local order associated with processing can affect properties.展开更多
We investigate the anisotropic band structure and its evolution under tensile strains along different crystallographic directions in bulk black phosphorus(BP)using angle-resolved photoemission spectroscopy and density...We investigate the anisotropic band structure and its evolution under tensile strains along different crystallographic directions in bulk black phosphorus(BP)using angle-resolved photoemission spectroscopy and density functional theory.The results show that there are band crossings in the Z-L(armchair)direction.展开更多
Since market uncertainty,or volatility,serves as a crucial gauge for assessing the traits of market fluctuations,the link between stock market volume and price continues to be a focal point of interest in finance.This...Since market uncertainty,or volatility,serves as a crucial gauge for assessing the traits of market fluctuations,the link between stock market volume and price continues to be a focal point of interest in finance.This study examines the dynamic,nonlinear correlations between Chinese stock volatility,trading volume,and return using a hybrid approach that combines the Markov-switching regime with the vector autoregressive model(MS-VAR).The empirical findings are as follows:(1)The Chinese stock market can be divided into three regional systems:steady downward,steady upward,and high volatility.The three states have similar frequencies of occurrence,and their corresponding stable probabilities are not high,indicating that the Chinese stock market is unstable.(2)Asymmetric dynamic relationships exist between market volatility,investment return,and trading volume.For different regimes,while the effect of trading volume on volatility and return appears to be insignificant,the impacts of volatility and return on trading volume are considerably strong.(3)A regime-dependent,contemporaneous correlation between volatility and return is observed,which also reflects the behavior of the Chinese stock market“chasing up and down”.However,a positive contemporaneous correlation always exists between volatility and trading volumes in different regimes,indicating that uncertainty in the Chinese stock market is closely related to information inflow.展开更多
This study investigates mental health literacy among young and middle-aged urban and rural residents and the differences in mental health literacy,perceived social support and subjective well-being.From January to Feb...This study investigates mental health literacy among young and middle-aged urban and rural residents and the differences in mental health literacy,perceived social support and subjective well-being.From January to February 2022,620 participants(320 rural and 300 urban residents)from three provinces of China were selected by con-venience sampling.A general data questionnaire,mental health literacy scale,perceived social support scale and subjective well-being scale were administered.The mental health literacy scores of urban residents were 3.34±0.57 and those of rural residents were 2.73±0.79.The results of multiple regression analysis showed that the mental health literacy scores of rural residents were more significant than those of urban residents in terms of sex and age,while urban residents’mental health literacy scores were more significant than those of rural resi-dents in terms of monthly income.Mental health literacy,perceived social support and subjective well-being of young and middle-aged urban and rural residents were all positively correlated(P<0.01).While the level of mental health literacy is better among urban residents than rural residents,perceived social support plays a partial mediating role between mental health literacy and subjective well-being of both urban and rural residents,and should be the focus of researchers seeking to improve the level of well-being of residents.展开更多
Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and oc...Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and octahedral factor(μ)form the state-of-the-art criteria used to evaluate the perovskite crystallographic stability.We studied the crystallographic stabilities of halide and chalcogenide perovskites by exploring an effective alternative descriptor,the global instability index(GII)that was used as an indicator of the stability of perovskite oxides.We particularly focused on determining crystallographic reliability by calculating GII.We analyzed the bond valence models of the 243 halide and chalcogenide perovskites that occupied the lowest-energy cubic-phase structures determined by conducting the first-principles-based total energy minimization calculations.The decomposition energy(ΔHD)reflects the thermodynamic stability of the system and is considered as the benchmark that helps assess the effectiveness of GII in evaluating the crystallographic stability of the systems under study.The results indicated that the accuracy of predicting thermodynamic stability was significantly higher when GII(73.6%)was analyzed compared to the cases when t(55%)andμ(39.1%)were analyzed to determine the stability.The results obtained from the machine learning-based data mining method further indicate that GII is an important descriptor of the stability of the perovskite family.展开更多
Open framework structures(e.g.,ScF_(3),Sc_(2)W_(3O)_(12),etc.)exhibit significant potential for thermal expansion tailoring owing to their high atomic vibrational degrees of freedom and diverse connectivity between po...Open framework structures(e.g.,ScF_(3),Sc_(2)W_(3O)_(12),etc.)exhibit significant potential for thermal expansion tailoring owing to their high atomic vibrational degrees of freedom and diverse connectivity between polyhedral units,displaying positive/negative thermal expansion(PTE/NTE)coefficients at a certain temperature.Despite the proposal of several physical mechanisms to explain the origin of NTE,an accurate mapping relationship between the structural–compositional properties and thermal expansion behavior is still lacking.This deficiency impedes the rapid evaluation of thermal expansion properties and hinders the design and development of such materials.We developed an algorithm for identifying and characterizing the connection patterns of structural units in open-framework structures and constructed a descriptor set for the thermal expansion properties of this system,which is composed of connectivity and elemental information.Our developed descriptor,aided by machine learning(ML)algorithms,can effectively learn the thermal expansion behavior in small sample datasets collected from literature-reported experimental data(246 samples).The trained model can accurately distinguish the thermal expansion behavior(PTE/NTE),achieving an accuracy of 92%.Additionally,our model predicted six new thermodynamically stable NTE materials,which were validated through first-principles calculations.Our results demonstrate that developing effective descriptors closely related to thermal expansion properties enables ML models to make accurate predictions even on small sample datasets,providing a new perspective for understanding the relationship between connectivity and thermal expansion properties in the open framework structure.The datasets that were used to support these results are available on Science Data Bank,accessible via the link https://doi.org/10.57760/sciencedb.j00113.00100.展开更多
Assembly of two-dimensional (2D) nanomaterials into well-organized architectures is pivotal for controlling their function and enhancing performance. As a promising class of 2D nanomaterials, MXenes have attracted sig...Assembly of two-dimensional (2D) nanomaterials into well-organized architectures is pivotal for controlling their function and enhancing performance. As a promising class of 2D nanomaterials, MXenes have attracted significant interest for use in wearable electronics due to their unique electrical and mechanical properties. However, facile approaches for fabricating MXenes into macroscopic fibers with controllable structures are limited. In this study, we present a strategy for easily spinning MXene fibers by incorporating polyanions. The introduction of poly(acrylic acid) (PAA) into MXene colloids has been found to alter MXene aggregation behavior, resulting in a reduced concentration threshold for lyotropic liquid crystal phase. This modification also enhances the viscosity and shear sensitivity of MXene colloids. Consequently, we were able to draw continuous fibers directly from the gel of MXene aggregated with PAA. These fibers exhibit homogeneous diameter and high alignment of MXene nanosheets, attributed to the shear-induced long-range order of the liquid crystal phase. Furthermore, we demonstrate proof-of-concept applications of the ordered MXene fibers, including textile-based supercapacitor, sensor and electrical thermal management, highlighting their great potential applied in wearable electronics. This work provides a guideline for processing 2D materials into controllable hierarchical structures by regulating aggregation behavior through the addition of ionic polymers.展开更多
Chimeric antigen receptor T (CAR-T) cell therapy is a novel cellular immunotherapy that is widely used to treat hematological malignancies, including acute leukemia, lymphoma, and multiple myeloma. Despite its remarka...Chimeric antigen receptor T (CAR-T) cell therapy is a novel cellular immunotherapy that is widely used to treat hematological malignancies, including acute leukemia, lymphoma, and multiple myeloma. Despite its remarkable clinical effects, this therapy has side effects that cannot be underestimated. Cytokine release syndrome (CRS) is one of the most clinically important and potentially life-threatening toxicities. This syndrome is a systemic immune storm that involves the mass cytokines releasing by activated immune cells. This phenomenon causes multisystem damages and sometimes even death. In this study, we reported the management of a patient with recurrent and refractory multiple myeloma and three patients with acute lymphocytic leukemia who suffered CRS during CAR-T treatment. The early application of tocilizumab, an anti-IL-6 receptor antibody, according to toxicity grading and clinical manifestation is recommended especially for patients who suffer continuous hyperpyrexia, hypotensive shock, acute respiratory failure, and whose CRS toxicities deteriorated rapidly. Moreover, low doses of dexamethasone (5-10 mg/day) were used for refractory CRS not responding to tocilizumab. The effective management of the toxicities associated with CRS will bring additional survival opportunities and improve the quality of life for patients with cancer.展开更多
Watermelon,Citrullus lanatus,is the world's third largest fruit crop.Reference genomes with gaps and a narrow genetic base hinder functional genomics and genetic improvement of watermelon.Here,we report the assemb...Watermelon,Citrullus lanatus,is the world's third largest fruit crop.Reference genomes with gaps and a narrow genetic base hinder functional genomics and genetic improvement of watermelon.Here,we report the assembly of a telomere-to-telomere gap-free genome of the elite watermelon inbred line G42 by incorporating high-coverage and accurate long-read sequencing data with multiple assembly strategies.All 11 chromosomes have been assembled into single-contig pseudomolecules without gaps,representing the highest completeness and assembly quality to date.The G42 reference genome is 369321829 bp in length and contains 24205 predicted protein-coding genes,with all 22 telomeres and 11 centromeres characterized.Furthermore,we established a pollen-EMS mutagenesis protocol and obtained over 200000M1 seeds from G42.In a sampling pool,48 monogenic phenotypic mutations,selected from 223M1and 78 M2 mutants with morphological changes,were confirmed.The average mutation density was 1 SNP/1.69Mband1 indel/4.55 Mb per M1 plant and 1SNP/1.08Mb and 1 indel/6.25 Mb per M2 plant.Taking advantage of the gap-free G42 genome,8039 mutations from 32 plants sampled from M1 and M2 families were identified with 100%accuracy,whereas only 25% of the randomly selected mutations identified using the 97103v2 reference genome could be confirmed.Using this library and the gap-free genome,two genes responsible for elongated fruit shape and male sterility(CiMs1)were identified,both caused by a single basechange from G to A.The validated gap-free genome and its EMS mutation library provide invaluable resources for functional genomics and genetic improvement of watermelon.展开更多
Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two tel...Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two telomere-to-telomere kiwifruit genomes from Actinidia chinensis var.‘Donghong’(DH)and Actinidia latifolia‘Kuoye’(KY),with total lengths of 608327852 and 640561626 bp for 29 chromosomes,respectively.With a burst of structural variants involving inversion,translocations,and duplications within 8.39 million years,the metabolite content of DH and KY exhibited differences in saccharides,lignans,and vitamins.A regulatory ERF098 transcription factor family has expanded in KY and Actinidia eriantha,both of which have ultra-high vitamin C content.With each assembly phased into two complete haplotypes,we identified allelic variations between two sets of haplotypes,leading to protein sequence variations in 26494 and 27773 gene loci and allele-specific expression of 4687 and 12238 homozygous gene pairs.Synchronized metabolome and transcriptome changes during DH fruit development revealed the same dynamic patterns in expression levels and metabolite contents;free fatty acids and flavonols accumulated in the early stages,but sugar substances and amino acids accumulated in the late stages.The AcSWEET9b gene that exhibits allelic dominance was further identified to positively correlate with high sucrose content in fruit.Compared with wild varieties and other Actinidia species,AcSWEET9b promoters were selected in red-flesh kiwifruits that have increased fruit sucrose content,providing a possible explanation on why red-flesh kiwifruits are sweeter.Collectively,these two gap-free kiwifruit genomes provide a valuable genetic resource for investigating domestication mechanisms and genome-based breeding of kiwifruit.展开更多
What determines the effectiveness of government entrepreneurship policies on the regional development of entrepreneurial activities in China? Using panel data analysis, this study develops a comprehensive framework t...What determines the effectiveness of government entrepreneurship policies on the regional development of entrepreneurial activities in China? Using panel data analysis, this study develops a comprehensive framework that examines the effects of various factors, including government efficiency and government support for business, finance and technology, on facilitating the creation of new ventures. Based on provincial data collected between 2009 and 2014, we find that the level of infrastructure development, government incubators and venture capital-guided funds have positive and significant effects on entrepreneurial activities. The findings of our study suggest that local government efficiency is a fundamental precondition for entrepreneurship policies to effectively boost the regional economy.展开更多
Kerogen is known as an important organic part for absorbing and forming shale gas whose absorption function,especially mechanical and tribological properties,has not been fully revealed.Here,we use Fourier transform i...Kerogen is known as an important organic part for absorbing and forming shale gas whose absorption function,especially mechanical and tribological properties,has not been fully revealed.Here,we use Fourier transform infrared(FTIR) and X-ray photoelectron spectroscopy(XPS) analysis to reveal the chemical structure of kerogen.We report the first study of the adhesion and friction behavior of kerogen using atomic force microscope(AFM) Nanoman technology.Our finding reveals the friction of kerogen is decreased at higher pressure while is inhibited at increased temperature,and friction decreases logarithmically as the sliding speed increases.The weakened of Al-O linkage at high temperature have great influence on the decrease of friction forces between kerogen and alumina pellet.This finding lays the mechanism for understanding the dynamic adhesion behavior of kerogen in frictions,therefore attracting increasing interests from scientists,researchers,petroleum engineers and investors.展开更多
Carbon dots(CDs) with multi-color emissive properties and a high photoluminescent quantum yield(PLQY) have attracted great attention recently due to their potential applications in chemical,environmental,biological an...Carbon dots(CDs) with multi-color emissive properties and a high photoluminescent quantum yield(PLQY) have attracted great attention recently due to their potential applications in chemical,environmental,biological and photo-electronic fields.Solvent-dependent effect in photoluminescence provides a facial and effective approach to tune the emission of CDs.In this study,green emissive nitrogen-doped carbon dots(N-CDs) are synthesized from p-hydroquinone and ethylenediamine through a simple hydrothermal method.The as-prepared N-CDs possess a robust excitation-independent green luminescence and a high PLQY of up to 15.9%.Further spectroscopic characterization indicates that the high PLQY is achieved by the balance of nitrogen doping states and the surface passivation extent in CDs.The N-CDs also exhibit solvent-dependent multi-color emissive property and distinct PLQY in different solvents(the maximum can reach up to 25.3%).Furthermore,the as-prepared N-CDs are applied as fluorescence probes to detect acetone and H2O2 in water.This method has exhibited a low detection limit of acetone(less than 0.1 %) and a quick and linear response to the H_2O_2 with the concentration from 0 to 120 μmol/L.This work broadens the knowledge of applying CDs as probes in the bio and chemical sensing fields.展开更多
Two-dimensional layered materials(2DLMs)have attracted growing attention in optoelectronic devices due to their intriguing anisotropic physical properties.Different members of 2DLMs exhibit unique anisotropic electric...Two-dimensional layered materials(2DLMs)have attracted growing attention in optoelectronic devices due to their intriguing anisotropic physical properties.Different members of 2DLMs exhibit unique anisotropic electrical,optical,and thermal properties,fundamentally related to their crystal structure.Among them,directional heat transfer plays a vital role in the thermal management of electronic devices.Here,we use density functional theory calculations to investigate the thermal transport properties of representative layered materials:β-InSe,γ-InSe,MoS2,and h-BN.We found that the lattice thermal conductivities ofβ-InSe,γ-InSe,MoS_(2),and h-BN display diverse anisotropic behaviors with anisotropy ratios of 10.4,9.4,64.9,and 107.7,respectively.The analysis of the phonon modes further indicates that the phonon group velocity is responsible for the anisotropy of thermal transport.Furthermore,the low lattice thermal conductivity of the layered InSe mainly comes from low phonon group velocity and atomic masses.Our findings provide a fundamental physical understanding of the anisotropic thermal transport in layered materials.We hope this study could inspire the advancement of 2DLMs thermal management applications in next-generation integrated electronic and optoelectronic devices.展开更多
Achieving high efficiency and stable pure blue colloidal perovskite quantum dot(QD)light-emitting diodes(LEDs)is still an enormous challenge because blue emitters typically exhibit high defect density,low photolumines...Achieving high efficiency and stable pure blue colloidal perovskite quantum dot(QD)light-emitting diodes(LEDs)is still an enormous challenge because blue emitters typically exhibit high defect density,low photoluminescence quantum yield(PLQY)and easy phase dissociation.Herein,an organic cation composition modification strategy is used to synthesize high-performance pure blue perovskite quantum dots at room temperature.The synthesized FACsPb(Cl_(0.5)Br_(0.5))_(3) QDs show a bright photoluminescence with a high PLQY(65%),which is 6 times higher than the undoped samples.In addition,the photophysical properties of the FA cation doping was deeply illustrated through carrier dynamics and first principal calculation,which show lower defects,longer lifetime,and more reasonable band gap structure than undoped emitters.Consequently,pure blue FA-CsPb(Cl_(0.5)Br_(0.5))_(3) QDs light-emitting devices were fabricated and presented a maximum luminance of 1452 cdm^(−2),and an external quantum efficiency of 5.01% with an emission at 474 nm.The excellent photoelectric properties mainly originate from the enhanced blue QDs emitter and effective charge injection and exciton radiation.Our finding underscores this easy and feasible room temperature doping approach as an alternative strategy to blue perovskite QD LED development.展开更多
Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography.The designed iridium.complexes revealed surprisingly high catalytic activity in C-N bondformation of...Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography.The designed iridium.complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions.In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols,N,N'-(phenylmethylene)dibenzamide products we re unexpectedly isolated under non-coordinating anion conditions,whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions.The mechanism explorations excluded the possibility of"silver effect"(silver-assisted or bimetallic catalysis)and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions.This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.展开更多
基金financially supported by the National Key Research and Development Program of China(2022YFE0206300)the National Natural Science Foundation of China(U21A2081,22075074,22209047)+1 种基金the Natural Science Foundation of Hunan Province(2022JJ40140)the Hunan Provincial Department of Education Outstanding Youth Project(22B0864,23B0037)。
文摘The Li metal battery with ultrahigh-nickel cathode(LiNi_(x)M_(1-x)O_(2),M=Mn,Co,and x≥0.9)under high-voltage is regarded as one of the most promising approaches to fulfill the ambitious target of 400 Wh/kg.However,the practical application is impeded by the instability of electrode/electrolyte interface and Ni-rich cathode itself.Herein we proposed an electron-defect electrolyte additive trimethyl borate(TMB)which is paired with the commercial carbonate electrolyte to construct highly conductive fluorine-and boron-rich cathode electrolyte interface(CEI)on LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM90)surface and solid electrolyte interphase(SEI)on lithium metal surface.The modified CEI effectively mitigates the structural transformation from layered to disordered rock-salt phase,and consequently alleviate the dissolution of transition metal ions(TMs)and its“cross-talk”effect,while the enhanced SEI enables stable lithium plating/striping and thus demonstrated good compatibility between electrolyte and lithium metal anode.As a result,the common electrolyte with 1 wt%TMB enables 4.7 V NCM90/Li cell cycle stably over 100 cycles with 70%capacity retention.This work highlights the significance of the electron-defect boron compounds for designing desirable interfacial chemistries to achieve high performance NCM90/Li battery under high voltage operation.
基金financially supported by the National Natural Science Foundation of China with grant number of 22172082 and 21978137。
文摘The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.
基金supported by the National Natural Science Foundation of China(Grant Nos.62125402,22090044,and 12350410372)the National Key Research and Development Program of China(Grant No.2022YFA1402501)Graduate Innovation Fund of Jilin University(Grant No.2022118)。
文摘Site disorder exists in some practical semiconductors and can significantly impact their intrinsic properties both beneficially and detrimentally.However,the uncertain local order and structure pose a challenge for experimental and theoretical research.Especially,it hinders the investigation of the effects of the diverse local atomic environments resulting from the site disorder.We employ the special quasi-random structure method to perform first-principles research on connection between local site disorder and electronic/optical properties,using cationdisordered AgBiS_(2)(rock salt phase)as an example.We predict that cation-disordered AgBiS_(2)has a bandgap ranging from 0.6 to 0.8 eV without spin-orbit coupling and that spin-orbit coupling reduces this by approximately 0.3 eV.We observe the effects of local structural features in the disordered lattice,such as the one-dimensional chain-like aggregation of cations that results in formation of doping energy bands near the band edges,formation and broadening of band-tail states,and the disturbance in the local electrostatic potential,which significantly reduces the bandgap and stability.The influence of these ordered features on the optical properties is confined to alterations in the bandgap and does not markedly affect the joint density of states or optical absorption.Our study provides a research roadmap for exploring the electronic structure of site-disordered semiconductor materials,suggests that the ordered chain-like aggregation of cations is an effective way to regulate the bandgap of AgBiS_(2),and provides insight into how variations in local order associated with processing can affect properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.12104216,12241403,and 61974061)the National Key R&D Program of China(Grant No.2021YFB3601600)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20140054)。
文摘We investigate the anisotropic band structure and its evolution under tensile strains along different crystallographic directions in bulk black phosphorus(BP)using angle-resolved photoemission spectroscopy and density functional theory.The results show that there are band crossings in the Z-L(armchair)direction.
基金This work was partially supported by the National Natural Science Foundation of China(Grant No.:72171192)the MOE Layout Foundation of Humanities and Social Sciences(Grant No.:22YJA790007)+1 种基金the Science and Technology Innovation Program of Hunan Province(Grant No.:2021RC3057)the Youth Innovation Team of Shanxi University,and the Fundamental Research Funds for the Central Universities.
文摘Since market uncertainty,or volatility,serves as a crucial gauge for assessing the traits of market fluctuations,the link between stock market volume and price continues to be a focal point of interest in finance.This study examines the dynamic,nonlinear correlations between Chinese stock volatility,trading volume,and return using a hybrid approach that combines the Markov-switching regime with the vector autoregressive model(MS-VAR).The empirical findings are as follows:(1)The Chinese stock market can be divided into three regional systems:steady downward,steady upward,and high volatility.The three states have similar frequencies of occurrence,and their corresponding stable probabilities are not high,indicating that the Chinese stock market is unstable.(2)Asymmetric dynamic relationships exist between market volatility,investment return,and trading volume.For different regimes,while the effect of trading volume on volatility and return appears to be insignificant,the impacts of volatility and return on trading volume are considerably strong.(3)A regime-dependent,contemporaneous correlation between volatility and return is observed,which also reflects the behavior of the Chinese stock market“chasing up and down”.However,a positive contemporaneous correlation always exists between volatility and trading volumes in different regimes,indicating that uncertainty in the Chinese stock market is closely related to information inflow.
基金supported by the Philosophy and Social Science Planning Project of Henan Province(2020BSH015).
文摘This study investigates mental health literacy among young and middle-aged urban and rural residents and the differences in mental health literacy,perceived social support and subjective well-being.From January to February 2022,620 participants(320 rural and 300 urban residents)from three provinces of China were selected by con-venience sampling.A general data questionnaire,mental health literacy scale,perceived social support scale and subjective well-being scale were administered.The mental health literacy scores of urban residents were 3.34±0.57 and those of rural residents were 2.73±0.79.The results of multiple regression analysis showed that the mental health literacy scores of rural residents were more significant than those of urban residents in terms of sex and age,while urban residents’mental health literacy scores were more significant than those of rural resi-dents in terms of monthly income.Mental health literacy,perceived social support and subjective well-being of young and middle-aged urban and rural residents were all positively correlated(P<0.01).While the level of mental health literacy is better among urban residents than rural residents,perceived social support plays a partial mediating role between mental health literacy and subjective well-being of both urban and rural residents,and should be the focus of researchers seeking to improve the level of well-being of residents.
基金supported by the National Natural Science Foundation of China(62004080 and 92061113)the Postdoctoral Innovative Talents Supporting Program(BX20190143)the China Postdoctoral Science Foundation(2020M670834)。
文摘Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and octahedral factor(μ)form the state-of-the-art criteria used to evaluate the perovskite crystallographic stability.We studied the crystallographic stabilities of halide and chalcogenide perovskites by exploring an effective alternative descriptor,the global instability index(GII)that was used as an indicator of the stability of perovskite oxides.We particularly focused on determining crystallographic reliability by calculating GII.We analyzed the bond valence models of the 243 halide and chalcogenide perovskites that occupied the lowest-energy cubic-phase structures determined by conducting the first-principles-based total energy minimization calculations.The decomposition energy(ΔHD)reflects the thermodynamic stability of the system and is considered as the benchmark that helps assess the effectiveness of GII in evaluating the crystallographic stability of the systems under study.The results indicated that the accuracy of predicting thermodynamic stability was significantly higher when GII(73.6%)was analyzed compared to the cases when t(55%)andμ(39.1%)were analyzed to determine the stability.The results obtained from the machine learning-based data mining method further indicate that GII is an important descriptor of the stability of the perovskite family.
基金the National Natural Science Foundation of China(Grant Nos.12004131,22090044,62125402,and 92061113)。
文摘Open framework structures(e.g.,ScF_(3),Sc_(2)W_(3O)_(12),etc.)exhibit significant potential for thermal expansion tailoring owing to their high atomic vibrational degrees of freedom and diverse connectivity between polyhedral units,displaying positive/negative thermal expansion(PTE/NTE)coefficients at a certain temperature.Despite the proposal of several physical mechanisms to explain the origin of NTE,an accurate mapping relationship between the structural–compositional properties and thermal expansion behavior is still lacking.This deficiency impedes the rapid evaluation of thermal expansion properties and hinders the design and development of such materials.We developed an algorithm for identifying and characterizing the connection patterns of structural units in open-framework structures and constructed a descriptor set for the thermal expansion properties of this system,which is composed of connectivity and elemental information.Our developed descriptor,aided by machine learning(ML)algorithms,can effectively learn the thermal expansion behavior in small sample datasets collected from literature-reported experimental data(246 samples).The trained model can accurately distinguish the thermal expansion behavior(PTE/NTE),achieving an accuracy of 92%.Additionally,our model predicted six new thermodynamically stable NTE materials,which were validated through first-principles calculations.Our results demonstrate that developing effective descriptors closely related to thermal expansion properties enables ML models to make accurate predictions even on small sample datasets,providing a new perspective for understanding the relationship between connectivity and thermal expansion properties in the open framework structure.The datasets that were used to support these results are available on Science Data Bank,accessible via the link https://doi.org/10.57760/sciencedb.j00113.00100.
基金financially supported this work through a Project Grant(No.KAW2020.0033)We acknowledge Myfab at Uppsala University for providing facilities and experimental support+2 种基金Myfab is funded by the Swedish Research Council(No.2019-00207)as a Swedish national research infrastructureThe authors acknowledge the financial support by the Fundamental Research Funds for the Central Universities of China(No.20822041H4077)ÅForsk Foundation.
文摘Assembly of two-dimensional (2D) nanomaterials into well-organized architectures is pivotal for controlling their function and enhancing performance. As a promising class of 2D nanomaterials, MXenes have attracted significant interest for use in wearable electronics due to their unique electrical and mechanical properties. However, facile approaches for fabricating MXenes into macroscopic fibers with controllable structures are limited. In this study, we present a strategy for easily spinning MXene fibers by incorporating polyanions. The introduction of poly(acrylic acid) (PAA) into MXene colloids has been found to alter MXene aggregation behavior, resulting in a reduced concentration threshold for lyotropic liquid crystal phase. This modification also enhances the viscosity and shear sensitivity of MXene colloids. Consequently, we were able to draw continuous fibers directly from the gel of MXene aggregated with PAA. These fibers exhibit homogeneous diameter and high alignment of MXene nanosheets, attributed to the shear-induced long-range order of the liquid crystal phase. Furthermore, we demonstrate proof-of-concept applications of the ordered MXene fibers, including textile-based supercapacitor, sensor and electrical thermal management, highlighting their great potential applied in wearable electronics. This work provides a guideline for processing 2D materials into controllable hierarchical structures by regulating aggregation behavior through the addition of ionic polymers.
文摘Chimeric antigen receptor T (CAR-T) cell therapy is a novel cellular immunotherapy that is widely used to treat hematological malignancies, including acute leukemia, lymphoma, and multiple myeloma. Despite its remarkable clinical effects, this therapy has side effects that cannot be underestimated. Cytokine release syndrome (CRS) is one of the most clinically important and potentially life-threatening toxicities. This syndrome is a systemic immune storm that involves the mass cytokines releasing by activated immune cells. This phenomenon causes multisystem damages and sometimes even death. In this study, we reported the management of a patient with recurrent and refractory multiple myeloma and three patients with acute lymphocytic leukemia who suffered CRS during CAR-T treatment. The early application of tocilizumab, an anti-IL-6 receptor antibody, according to toxicity grading and clinical manifestation is recommended especially for patients who suffer continuous hyperpyrexia, hypotensive shock, acute respiratory failure, and whose CRS toxicities deteriorated rapidly. Moreover, low doses of dexamethasone (5-10 mg/day) were used for refractory CRS not responding to tocilizumab. The effective management of the toxicities associated with CRS will bring additional survival opportunities and improve the quality of life for patients with cancer.
基金This work was supported by the Provincial Technology Innovation Program of Shandong,Ningxia Hui Autonomous Region agricultural breeding special project(NXNYYZ202001)Jiangsu Seed Industry Revitalization Competitive Project JBGS(2021)072,Ningbo Science and Technology Innovation Project 2021Z132,and Weifang Seed InnovationGroup.
文摘Watermelon,Citrullus lanatus,is the world's third largest fruit crop.Reference genomes with gaps and a narrow genetic base hinder functional genomics and genetic improvement of watermelon.Here,we report the assembly of a telomere-to-telomere gap-free genome of the elite watermelon inbred line G42 by incorporating high-coverage and accurate long-read sequencing data with multiple assembly strategies.All 11 chromosomes have been assembled into single-contig pseudomolecules without gaps,representing the highest completeness and assembly quality to date.The G42 reference genome is 369321829 bp in length and contains 24205 predicted protein-coding genes,with all 22 telomeres and 11 centromeres characterized.Furthermore,we established a pollen-EMS mutagenesis protocol and obtained over 200000M1 seeds from G42.In a sampling pool,48 monogenic phenotypic mutations,selected from 223M1and 78 M2 mutants with morphological changes,were confirmed.The average mutation density was 1 SNP/1.69Mband1 indel/4.55 Mb per M1 plant and 1SNP/1.08Mb and 1 indel/6.25 Mb per M2 plant.Taking advantage of the gap-free G42 genome,8039 mutations from 32 plants sampled from M1 and M2 families were identified with 100%accuracy,whereas only 25% of the randomly selected mutations identified using the 97103v2 reference genome could be confirmed.Using this library and the gap-free genome,two genes responsible for elongated fruit shape and male sterility(CiMs1)were identified,both caused by a single basechange from G to A.The validated gap-free genome and its EMS mutation library provide invaluable resources for functional genomics and genetic improvement of watermelon.
基金supported by the Provincial Technology Innovation Program of Shandongan award from the Natural Science Foundation of Shandong Province(ZR2021ZD30)+2 种基金the Director’s Award from the Peking University Institute of Advanced Agricultural Sciences,the National Top Young Talents Program of Chinathe Boya Postdoctoral Program of Peking University,the National Key R&D Program of China(2019YFD1000200)the Youth Innovation Promotion Association CAS(2018376).
文摘Kiwifruit is a recently domesticated horticultural fruit crop with substantial economic and nutritional value,especially because of the high content of vitamin C in its fruit.In this study,we de novo assembled two telomere-to-telomere kiwifruit genomes from Actinidia chinensis var.‘Donghong’(DH)and Actinidia latifolia‘Kuoye’(KY),with total lengths of 608327852 and 640561626 bp for 29 chromosomes,respectively.With a burst of structural variants involving inversion,translocations,and duplications within 8.39 million years,the metabolite content of DH and KY exhibited differences in saccharides,lignans,and vitamins.A regulatory ERF098 transcription factor family has expanded in KY and Actinidia eriantha,both of which have ultra-high vitamin C content.With each assembly phased into two complete haplotypes,we identified allelic variations between two sets of haplotypes,leading to protein sequence variations in 26494 and 27773 gene loci and allele-specific expression of 4687 and 12238 homozygous gene pairs.Synchronized metabolome and transcriptome changes during DH fruit development revealed the same dynamic patterns in expression levels and metabolite contents;free fatty acids and flavonols accumulated in the early stages,but sugar substances and amino acids accumulated in the late stages.The AcSWEET9b gene that exhibits allelic dominance was further identified to positively correlate with high sucrose content in fruit.Compared with wild varieties and other Actinidia species,AcSWEET9b promoters were selected in red-flesh kiwifruits that have increased fruit sucrose content,providing a possible explanation on why red-flesh kiwifruits are sweeter.Collectively,these two gap-free kiwifruit genomes provide a valuable genetic resource for investigating domestication mechanisms and genome-based breeding of kiwifruit.
文摘What determines the effectiveness of government entrepreneurship policies on the regional development of entrepreneurial activities in China? Using panel data analysis, this study develops a comprehensive framework that examines the effects of various factors, including government efficiency and government support for business, finance and technology, on facilitating the creation of new ventures. Based on provincial data collected between 2009 and 2014, we find that the level of infrastructure development, government incubators and venture capital-guided funds have positive and significant effects on entrepreneurial activities. The findings of our study suggest that local government efficiency is a fundamental precondition for entrepreneurship policies to effectively boost the regional economy.
基金This project was supported by the National Natural Science Foundation of China(No.51875577)the Beijing Nova Program(No.2171100001117058)the Science Foundation of China University of Petroleum-Beijing(No.2462018BJC004)。
文摘Kerogen is known as an important organic part for absorbing and forming shale gas whose absorption function,especially mechanical and tribological properties,has not been fully revealed.Here,we use Fourier transform infrared(FTIR) and X-ray photoelectron spectroscopy(XPS) analysis to reveal the chemical structure of kerogen.We report the first study of the adhesion and friction behavior of kerogen using atomic force microscope(AFM) Nanoman technology.Our finding reveals the friction of kerogen is decreased at higher pressure while is inhibited at increased temperature,and friction decreases logarithmically as the sliding speed increases.The weakened of Al-O linkage at high temperature have great influence on the decrease of friction forces between kerogen and alumina pellet.This finding lays the mechanism for understanding the dynamic adhesion behavior of kerogen in frictions,therefore attracting increasing interests from scientists,researchers,petroleum engineers and investors.
基金National Science Foundation of China(No.31340014)Beijing Nova Program Interdisciplinary Studies Cooperative Project(No.Z181100006218138)the Research Program of Yongchuan Science and Technology Commission(Ycstc,No.2018nb1402)for the support。
文摘Carbon dots(CDs) with multi-color emissive properties and a high photoluminescent quantum yield(PLQY) have attracted great attention recently due to their potential applications in chemical,environmental,biological and photo-electronic fields.Solvent-dependent effect in photoluminescence provides a facial and effective approach to tune the emission of CDs.In this study,green emissive nitrogen-doped carbon dots(N-CDs) are synthesized from p-hydroquinone and ethylenediamine through a simple hydrothermal method.The as-prepared N-CDs possess a robust excitation-independent green luminescence and a high PLQY of up to 15.9%.Further spectroscopic characterization indicates that the high PLQY is achieved by the balance of nitrogen doping states and the surface passivation extent in CDs.The N-CDs also exhibit solvent-dependent multi-color emissive property and distinct PLQY in different solvents(the maximum can reach up to 25.3%).Furthermore,the as-prepared N-CDs are applied as fluorescence probes to detect acetone and H2O2 in water.This method has exhibited a low detection limit of acetone(less than 0.1 %) and a quick and linear response to the H_2O_2 with the concentration from 0 to 120 μmol/L.This work broadens the knowledge of applying CDs as probes in the bio and chemical sensing fields.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1402502)the National Natural Science Foundation of China(Grant Nos.12004131,22090044,and 62125402)Calculations were performed in part at the high-performance computing center of Jilin University.
文摘Two-dimensional layered materials(2DLMs)have attracted growing attention in optoelectronic devices due to their intriguing anisotropic physical properties.Different members of 2DLMs exhibit unique anisotropic electrical,optical,and thermal properties,fundamentally related to their crystal structure.Among them,directional heat transfer plays a vital role in the thermal management of electronic devices.Here,we use density functional theory calculations to investigate the thermal transport properties of representative layered materials:β-InSe,γ-InSe,MoS2,and h-BN.We found that the lattice thermal conductivities ofβ-InSe,γ-InSe,MoS_(2),and h-BN display diverse anisotropic behaviors with anisotropy ratios of 10.4,9.4,64.9,and 107.7,respectively.The analysis of the phonon modes further indicates that the phonon group velocity is responsible for the anisotropy of thermal transport.Furthermore,the low lattice thermal conductivity of the layered InSe mainly comes from low phonon group velocity and atomic masses.Our findings provide a fundamental physical understanding of the anisotropic thermal transport in layered materials.We hope this study could inspire the advancement of 2DLMs thermal management applications in next-generation integrated electronic and optoelectronic devices.
基金the National Natural Science Foundation of China(No.61804063)the National Key Research and Development Program of China(No.2019YFA0705900)funded by MOST.+4 种基金Key Projects of Jilin Province Science and Technology Development Plan(No.20220201070GX)the Natural Science Foundation of Jilin Province(No.20190201208JC)the support from the Hong Kong Research Grant Council for the GRF grant(No.11314122)research funding from the City University of Hong Kong and the support from Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302007)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(No.2019B121205002).
文摘Achieving high efficiency and stable pure blue colloidal perovskite quantum dot(QD)light-emitting diodes(LEDs)is still an enormous challenge because blue emitters typically exhibit high defect density,low photoluminescence quantum yield(PLQY)and easy phase dissociation.Herein,an organic cation composition modification strategy is used to synthesize high-performance pure blue perovskite quantum dots at room temperature.The synthesized FACsPb(Cl_(0.5)Br_(0.5))_(3) QDs show a bright photoluminescence with a high PLQY(65%),which is 6 times higher than the undoped samples.In addition,the photophysical properties of the FA cation doping was deeply illustrated through carrier dynamics and first principal calculation,which show lower defects,longer lifetime,and more reasonable band gap structure than undoped emitters.Consequently,pure blue FA-CsPb(Cl_(0.5)Br_(0.5))_(3) QDs light-emitting devices were fabricated and presented a maximum luminance of 1452 cdm^(−2),and an external quantum efficiency of 5.01% with an emission at 474 nm.The excellent photoelectric properties mainly originate from the enhanced blue QDs emitter and effective charge injection and exciton radiation.Our finding underscores this easy and feasible room temperature doping approach as an alternative strategy to blue perovskite QD LED development.
基金financial support from the National Natural Science Foundation of China(Nos.21776111,21861039)the Fundamental Research Funds for the Central Universities(No.JUSRP 51627B)the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(No.B13025)。
文摘Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography.The designed iridium.complexes revealed surprisingly high catalytic activity in C-N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions.In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols,N,N'-(phenylmethylene)dibenzamide products we re unexpectedly isolated under non-coordinating anion conditions,whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions.The mechanism explorations excluded the possibility of"silver effect"(silver-assisted or bimetallic catalysis)and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions.This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C-N bond formation.