Alloy-typed anode materials,endowed innately with high theoretical specific capacity,hold great promise as an alternative to intercalation-typed counterparts for alkali-ion batteries.Despite tremendous efforts devoted...Alloy-typed anode materials,endowed innately with high theoretical specific capacity,hold great promise as an alternative to intercalation-typed counterparts for alkali-ion batteries.Despite tremendous efforts devoted to addressing drastic volume change and severe pulverization issues of such anodes,the underlying mechanisms involving dynamic phase evolutions and reaction kinetics have not yet been fully comprehended.Herein,taking antimony(Sb)anode as a representative paradigm,its microscopic operating mechanisms down to the atomic scale during live(de)potassiation cycling are systematically unraveled using in situ transmission electron microscopy.Highly reversible phase transformations at single-particle level,that are Sb←→KSb_(2)←→KSb←→K_5Sb_(4)←→K_(3)Sb,were revealed during cycling.Meanwhile,multiple phase interfaces associated with different reaction kinetics coexisted and this phenomenon was properly elucidated in the context of density functional theory calculations.Impressively,previously unexplored unidirectional circulation of reaction interfaces within individual Sb particle is confirmed for both potassiation and depotassiation.Based on the empirical results,the surface diffusion-mediated potassiation-depotassiation pathways at single-particle level are suggested.This work affords new insights into energy storage mechanisms of Sb anode and valuable guidance for targeted optimization of alloy-typed anodes(not limited to Sb)toward advanced potassium-ion batteries.展开更多
Tight gas reservoirs with mobile water exhibit multi-phase flow and high stress sensitivity.Accurately analyzing the reservoir and well parameters using conventional single-phase rate transient analysis methods proves...Tight gas reservoirs with mobile water exhibit multi-phase flow and high stress sensitivity.Accurately analyzing the reservoir and well parameters using conventional single-phase rate transient analysis methods proves challenging.This study introduces novel rate transient analysis methods incorporating evaluation processes based on the conventional flowing material balance method and the Blasingame type-curve method to examine fractured gas wells producing water.By positing a gas-water two-phase equivalent homogenous phase that considers characteristics of mobile water,gas,and high stress sensitivity,the conventional single-phase rate transient analysis methods can be applied by integrating the phase's characteristics and defining the phase's normalized parameters and material balance pseudotime.The rate transient analysis methods based on the equivalent homogenous phase can be used to quantitatively assess the parameters of wells and gas reservoirs,such as original gas-in-place,fracture half-length,reservoir permeability,and well drainage radius.This facilitates the analysis of production dynamics of fractured wells and well-controlled areas,subsequently aiding in locating residual gas and guiding the configuration of well patterns.The specific evaluation processes are detailed.Additionally,a numerical simulation mechanism model was constructed to verify the reliability of the developed methods.The methods introduced have been successfully implemented in field water-producing gas wells within tight gas reservoirs containing mobile water.展开更多
MXenes are two-dimensional transition metal carbides and/or nitrides with unique physiochemical properties and have attracted extensive interest in numerous fields.However,current MXene synthesis methods are limited b...MXenes are two-dimensional transition metal carbides and/or nitrides with unique physiochemical properties and have attracted extensive interest in numerous fields.However,current MXene synthesis methods are limited by hazardous synthesis conditions,high production costs,or difficulty in largescale production.Therefore,a general,safe,cost-effective,and scalable synthesis method for MXenes is crucial.Here,we report the fast synthesis of MXenes in the open air using a molten salt-shielded synthesis(MS^(3))method,which uses Lewis-acid salts as etchants and a low-melting-point eutectic salt mixture as the reaction medium and shield to prevent MXene oxidation at high temperatures.Carbide and nitride MXenes,including Ti_(3)C_(2)T_(x),Ti_(2)CT_(x),Ti_(3)CNT_(x),and Ti_(4)N_(3)T_(x),were successfully synthesized using the MS^(3) method.We also present the flexibility of the MS^(3) method by scaling the etching process to large batches of 20 and 60 g of Ti_(3)AlC_(2) MAX precursor in one pot.When used as negative electrodes,the prepared MS^(3)-MXenes delivered excellent electrochemical properties for high-rate Li-ion storage.展开更多
A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",i...A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",is proposed in this work.It is demonstrated PDFE-20 possesses a room-temperature ionic conductivity of 3.31×10^(-3) S cm^(-1),an ionic diffusion activation energy of 0.10 eV,and an oxidation potential of 4.4 V.SMBs based on PDFE-20 and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes were evaluated with an active material mass loading of 6.8 mg cm^(-2).The cell displayed an initial discharge specific capacity of 104 mA h g^(-1),and97.1%capacity retention after 100 cycles at 0.5 C.In-situ polymerization conformally coats the anode/-cathode interfaces,avoiding geometrical gaps and high charge transfer resistance with ex-situ polymerization of the same chemistry.FEC acts as a plasticizer during polymerization to suppress crystallization and significantly improves ionic transport.During battery cycling FEC promotes mechanical congruence of electrolyte-electrode interfaces while forming a stable NaF-rich solid electrolyte interphase(SEI)at the anode.Density functional theory(DFT)calculations were also performed to further understand the role FEC in the poly(DOL)-FEC electrolytes.This work broadens the application of in-situ prepared poly(DOL)electrolytes to sodium storage and demonstrates the crucial role of FEC in improving the electrochemical performance.展开更多
A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes ...A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.展开更多
Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engi...Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engineering applications.In this work,longitudinal compression,bending,longitudinal shear,longitudinal tensile,transverse compression and transverse tensile tests of bamboo materials are conducted,considering the influence of the bamboo nodes.The mechanical properties of the whole bamboo stalk with the wall thickness and outer circumference are explored.Through univariate and multiple regression analysis,the relationship between mechanical properties and wall thickness and perimeter is fitted,and the conversion parameters between different mechanical properties are derived.The research results show that the transverse compressive strength of nodal specimen,and transverse tensile strength of nodal and inter-node specimens increase with the increase of wall thickness and outer circumference,but other mechanical properties decrease with the increase of wall thickness and outer circumference.The prediction formula and conversion parameters of bamboo mechanical properties proposed in this research have high applicability and accuracy.Moreover,this research can provide references for the evaluation of bamboo performance and saving test costs.展开更多
The combination of traditional processors and Field Programmable Gate Arrays(FPGA)is shaping the future networking platform for intensive computation in resource-constrained networks and devices.These networks present...The combination of traditional processors and Field Programmable Gate Arrays(FPGA)is shaping the future networking platform for intensive computation in resource-constrained networks and devices.These networks present two key challenges of security and resource limitations.Lightweight ciphers are suitable to provide data security in such constrained environments.Implementing the lightweight PRESENT encryption algorithm in a reconfigurable platform(FPGAs)can offer secure communication service and flexibility.This paper presents hardware acceleration of security primitives in SDN using NETFPGA-10G.We implement an efficient design of the PRESENT algorithm for faster,smaller and lower power consumption hardware circuit using Verilog.We evaluate the performance of the hardware and software implementations of PRESENT.Experimental results prove that the proposed hardware design is a viable option for use in resource constrained devices in future networks and their applications.展开更多
The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor a...The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.展开更多
Since the development of organic food,to a great extent,depends on the needs of consumers,the studies on the consumer behavior of organic food would have far-reaching significance to the development of the whole organ...Since the development of organic food,to a great extent,depends on the needs of consumers,the studies on the consumer behavior of organic food would have far-reaching significance to the development of the whole organic food industry. The recent studies in this field mainly include the following four aspects: the consumers' recognition of organic food; the consumers' attitude towards organic food; the consumers' purchase of organic food; the consumers' willingness to pay. The paper would review the recent domestic and foreign studies on the four aspects mentioned above,aiming to provide references to the researches in this field.展开更多
Systematically analyze the composition of post-marketing adverse drug reaction data and the open mode in the EU, and summarize its characteristics. EU post-marketing ADR data is open to six categories of stakeholders:...Systematically analyze the composition of post-marketing adverse drug reaction data and the open mode in the EU, and summarize its characteristics. EU post-marketing ADR data is open to six categories of stakeholders: EMA, EC, medicines regulatory authorities in EEA member states, healthcare professionals and the public, Marketing Authorization Holders, academia, WHO and medicines regulatory authorities in third countries. The EU has implemented hierarchical opening for ADRs, with different levels containing different data and facing different stakeholders. Openness is divided into active and passive openness. In opening up data, the EU complies with relevant personal data protection laws to protect the privacy of individuals. The EU’s post-marketing adverse drug reaction data openness is characterized by a combination of data openness and privacy protection, active and passive openness, and a hierarchy of data openness. It is hoped that this can provide a reference for the opening up of post-marketing adverse drug reaction data in China.展开更多
Brachymeria lasus Walker is a solitary endoparasitoid that attacks the pupae of a wide range of lepidopteran hosts,including an important invasive species,the fall webworm(Hyphantria cunea Drury).We studied the relati...Brachymeria lasus Walker is a solitary endoparasitoid that attacks the pupae of a wide range of lepidopteran hosts,including an important invasive species,the fall webworm(Hyphantria cunea Drury).We studied the relationship between temperature and development of B.lasus from egg to adult hatching.The results show a decrease in parasitoid development time from 34.4 days at 18°C to 10.6 days at 32°C.The minimum threshold temperature of B.lasus was 13.2°C±1.7°C,and the eff ective accumulated temperature was 210.3±28.7 degree days.These results provide a basis for optimizing the production of this parasitoid.In addition,the eff ects of host size on off spring performance of B.lasus were investigated under laboratory conditions.Off spring longevity,size,and percentage of females were positively correlated with host size.Female off spring are larger and live longer than males.Furthermore,this research showed that parasitoid adults successfully emerged from approximately 27.9%of pupae.However,eclosion or hatching of H.cunea decreased dramatically,which may be due to damage caused by female B.lasus when testing hosts with their ovipositors or by feeding on them.The results suggest that B.lasus has the potential to become an effi cient natural enemy for controlling H.cunea.展开更多
Using the method in Biodiversity Risk and Opportunity Assessment Handbook of British American Tobacco Biodiversity Partnership,we assess biodiversity risks and opportunities in BAT and China's cooperative tobacco-...Using the method in Biodiversity Risk and Opportunity Assessment Handbook of British American Tobacco Biodiversity Partnership,we assess biodiversity risks and opportunities in BAT and China's cooperative tobacco-growing areas. The assessment results indicate that there are 8 risks and 1 opportunity. Action and monitoring plans have been made for medium and high risks as well as opportunity,to reduce impact on biodiversity.展开更多
Objective: To investigate the change of ATM phosphorylation in HepG2 cells and its effect on HepG2 cell survival under a continuous low dose-rate irradiation. Methods: HepG2 cells were exposed to equivalent doses of i...Objective: To investigate the change of ATM phosphorylation in HepG2 cells and its effect on HepG2 cell survival under a continuous low dose-rate irradiation. Methods: HepG2 cells were exposed to equivalent doses of irradiation deliv- ered at either a continuous low dose-rate (7.76 cGy/h) or a high dose-rate (4500 cGy/h). The ATM phosphorylated proteins and surviving fraction of HepG2 cell after low dose-rate irradiation were compared with that after equivalent doses of high dose-rate irradiation. Results: The phosphorylation of ATM protein was maximal at 0.5 Gy irradiation delivered at either a high dose-rate or a continuous low dose-rate. As the radiation dose increased, the phosphorylation of ATM protein decreased under continuous low dose-rate irradiation. However, the phosphorylation of ATM protein was remained stable under high dose-rate irradiation. When the phosphorylation of ATM protein under continuous low dose-rate irradiation was equal to that under high dose-rate irradiation, there was no significant difference in the surviving fraction of HepG2 cells between two ir- radiation methods (P > 0.05). When the phosphorylation of ATM protein significantly decreased after continuous low dose-rate irradiation compared with that after high dose-rate irradiation, increased amounts of cell killing was found in low dose-rate irradiation (P < 0.01). Conclusion: Continuous low dose-rate irradiation increases HepG2 cells radiosensitivity compared with high dose-rate irradiation. The increased amounts of cell killing following continuous low dose-rate exposures are associated with reduced ATM phosphorylated protein.展开更多
This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submissi...This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system,this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.展开更多
Being controlled by the gas content of the reservoir, the productivity of CBM well is also mainly determined by its engineering quality and the physical property of the reservoir. In Dafosi mine field, 22 vertical wel...Being controlled by the gas content of the reservoir, the productivity of CBM well is also mainly determined by its engineering quality and the physical property of the reservoir. In Dafosi mine field, 22 vertical wells from the “26 + 1” CBM wells project that was implemented since 2014 showed great difference in productivity after fracturing construction. With the consistent geological condition of coal reservoirs, fracturing construction parameters are suggested as the priority factor that controlling the well productivity. In this study, being combined with historical production and geological data, an optimized designation of fracturing construction parameters was established based on systematically comparative analysis of construction parameters such as discharge, the total volume of fracturing fluid, the quality of sand, sand ratio, which provides engineering basis for further fracturing construction of CBM wells.展开更多
Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention.Herein we construct the well-defined Mn single-atom(MnSA)catalyst with four N-c...Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention.Herein we construct the well-defined Mn single-atom(MnSA)catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions(CO_(2)RR)and oxygen reduction reactions(ORR).MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90%at-0.9 V for CO_(2)RR and higher H_(2)O_(2)yield from 0.1 to 0.6 V with excellent ORR activity.Density functional theory(DFT)calculations based on constant potential models were performed to study the mechanism of MnSA on CO_(2)RR.The thermodynamic energy barrier of CO_(2)RR is lowest at-0.9 V vs.reversible hydrogen electrode(RHE).Similar DFT calculations on the H_(2)O_(2)yield of ORR showed that the H_(2)O_(2)yield at 0.2 V was higher.This study provides a reasonable explanation for the role of electrode potential micro-environments.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
Phenolation is one of the effective strategies to synthesize lignin-based polyphenols,improve lignin’s properties,and extend its value-added applications in biological,medicinal and cosmetic fields.Herein,by taking t...Phenolation is one of the effective strategies to synthesize lignin-based polyphenols,improve lignin’s properties,and extend its value-added applications in biological,medicinal and cosmetic fields.Herein,by taking the structural feature advantage of lignin,an effective and green strategy was developed to molecularly engineer lignin into a robust lignin-3-(2-hydroxyphenyl)propionate ester(LPPE)derivative via a transesterification reaction between 3,4-dihydrocoumarin(DHC)and the aliphatic hydroxyls in lignin under organocatalysis.The strategy is optimized and the novel derivative was systematically characterized by ^(1)H,^(13)C and ^(31)P nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy.The findings indicated that the successful introduction of 3-(2-hydroxyphenyl)propionate groups using a OH groups/DHC/organic base mo-lar ratio of 1꞉1꞉0.3 at 120℃ for 6 h increased the content of phenolic hydroxyl groups from 1.7931 to 3.0179 mmol/g,and the LPPE exhibited excellent ultraviolet-absorbing and antioxidant per-formance with up to 90%free radical scavenging activity within 20 min using 5 mg/mL of LPPE.In addition,good biocompatibility and a high Sun protection factor(SPF)value of 40.9 were achieved at 5%(w)dosage of LPPE in the cream,indicating its significant application potential in sunscreen.展开更多
Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with ...Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with AGE in Shanghai from 2018 to 2021.The overall detection rate of NoV was 11.9%(181/1545),with annual detection rates of 9.4%(36/381),13.6%(29/213),5.8%(13/226)and 14.2%(103/725),respectively.Of note,the prevalence of NoV in 2020 was significantly lower than that in 2018-2019(10.9%,65/594)(P=0.023)and 2021(14.2%,103/725)(P=0.000).The 181 NoV strains identified in this study were classified into the GI group(1.1%,2/181),GII group(98.3%,178/181)and GIX group(0.6%,1/181)according to the VP1 gene.The most common NoV VP1 genotype was GII.4 Sydney_2012(63.5%,115/181),followed by GII.3(19.9%,36/181)and GII.2(9.4%,17/181).For P genotypes,174 strains were sequenced successfully according to the RdRp gene,and the predominant genotype was GII.P16(44.8%,78/174),followed by GII.P31(25.9%,45/174)and GII.P12(21.3%,37/174).Among the 174 cases,GII.4 Sydney_2012[P16](36.8%,64/174)was the dominant genotype,followed by GII.4 Sydney_2012[P31](25.3%,44/174),GII.3[P12](20.1%,35/174)and GII.2[P16](8.0%,14/174).In particular,the dominant genotypes in Shanghai changed from GII.4 Sydney_2012[P31]in 2018-2019 to GII.4 Sydney_2012[P16]in 2020-2021.This is the first report to describe the epidemiological changes in NoV infection before and during the COVID-19 pandemic in Shanghai.These data highlight the importance of continuous surveillance for NoV in children with AGE in Shanghai.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12174049,51972058)the Big Data Computing Center of Southeast University。
文摘Alloy-typed anode materials,endowed innately with high theoretical specific capacity,hold great promise as an alternative to intercalation-typed counterparts for alkali-ion batteries.Despite tremendous efforts devoted to addressing drastic volume change and severe pulverization issues of such anodes,the underlying mechanisms involving dynamic phase evolutions and reaction kinetics have not yet been fully comprehended.Herein,taking antimony(Sb)anode as a representative paradigm,its microscopic operating mechanisms down to the atomic scale during live(de)potassiation cycling are systematically unraveled using in situ transmission electron microscopy.Highly reversible phase transformations at single-particle level,that are Sb←→KSb_(2)←→KSb←→K_5Sb_(4)←→K_(3)Sb,were revealed during cycling.Meanwhile,multiple phase interfaces associated with different reaction kinetics coexisted and this phenomenon was properly elucidated in the context of density functional theory calculations.Impressively,previously unexplored unidirectional circulation of reaction interfaces within individual Sb particle is confirmed for both potassiation and depotassiation.Based on the empirical results,the surface diffusion-mediated potassiation-depotassiation pathways at single-particle level are suggested.This work affords new insights into energy storage mechanisms of Sb anode and valuable guidance for targeted optimization of alloy-typed anodes(not limited to Sb)toward advanced potassium-ion batteries.
文摘Tight gas reservoirs with mobile water exhibit multi-phase flow and high stress sensitivity.Accurately analyzing the reservoir and well parameters using conventional single-phase rate transient analysis methods proves challenging.This study introduces novel rate transient analysis methods incorporating evaluation processes based on the conventional flowing material balance method and the Blasingame type-curve method to examine fractured gas wells producing water.By positing a gas-water two-phase equivalent homogenous phase that considers characteristics of mobile water,gas,and high stress sensitivity,the conventional single-phase rate transient analysis methods can be applied by integrating the phase's characteristics and defining the phase's normalized parameters and material balance pseudotime.The rate transient analysis methods based on the equivalent homogenous phase can be used to quantitatively assess the parameters of wells and gas reservoirs,such as original gas-in-place,fracture half-length,reservoir permeability,and well drainage radius.This facilitates the analysis of production dynamics of fractured wells and well-controlled areas,subsequently aiding in locating residual gas and guiding the configuration of well patterns.The specific evaluation processes are detailed.Additionally,a numerical simulation mechanism model was constructed to verify the reliability of the developed methods.The methods introduced have been successfully implemented in field water-producing gas wells within tight gas reservoirs containing mobile water.
基金supported by the National Natural Science Foundation of China(Grant No.52072252,No.51902215)Sichuan Science and Technology Program(No.2020ZDZX0005)+4 种基金the Fundamental Research Funds for the Central Universities(YJ201886)the Agence Nationale de la Recherche(Labex STORE-EX)for financial supportsupported by the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(Grant No.2019R01003)Ningbo Top-talent Team Program,Ningbo Municipal Bureau of Science and Technology(Grant No.2018A610005)President’s International Fellowship Initiative of CAS(No.2021DE0002).
文摘MXenes are two-dimensional transition metal carbides and/or nitrides with unique physiochemical properties and have attracted extensive interest in numerous fields.However,current MXene synthesis methods are limited by hazardous synthesis conditions,high production costs,or difficulty in largescale production.Therefore,a general,safe,cost-effective,and scalable synthesis method for MXenes is crucial.Here,we report the fast synthesis of MXenes in the open air using a molten salt-shielded synthesis(MS^(3))method,which uses Lewis-acid salts as etchants and a low-melting-point eutectic salt mixture as the reaction medium and shield to prevent MXene oxidation at high temperatures.Carbide and nitride MXenes,including Ti_(3)C_(2)T_(x),Ti_(2)CT_(x),Ti_(3)CNT_(x),and Ti_(4)N_(3)T_(x),were successfully synthesized using the MS^(3) method.We also present the flexibility of the MS^(3) method by scaling the etching process to large batches of 20 and 60 g of Ti_(3)AlC_(2) MAX precursor in one pot.When used as negative electrodes,the prepared MS^(3)-MXenes delivered excellent electrochemical properties for high-rate Li-ion storage.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52072105 and 21676067)the Key R&D Program of Anhui Province(202104a05020044)+3 种基金the Anhui Provincial Natural Science Foundation(2108085J23)the Major Science and Technology Projects in Anhui Province(202003a05020014,2021e03020001)the Fundamental Research Funds for the Central Universities(PA2021KCPY0028,JZ2022HGTB0251)supported by the National Science Foundation,Division of Materials Research,Award Number 1938833。
文摘A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",is proposed in this work.It is demonstrated PDFE-20 possesses a room-temperature ionic conductivity of 3.31×10^(-3) S cm^(-1),an ionic diffusion activation energy of 0.10 eV,and an oxidation potential of 4.4 V.SMBs based on PDFE-20 and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes were evaluated with an active material mass loading of 6.8 mg cm^(-2).The cell displayed an initial discharge specific capacity of 104 mA h g^(-1),and97.1%capacity retention after 100 cycles at 0.5 C.In-situ polymerization conformally coats the anode/-cathode interfaces,avoiding geometrical gaps and high charge transfer resistance with ex-situ polymerization of the same chemistry.FEC acts as a plasticizer during polymerization to suppress crystallization and significantly improves ionic transport.During battery cycling FEC promotes mechanical congruence of electrolyte-electrode interfaces while forming a stable NaF-rich solid electrolyte interphase(SEI)at the anode.Density functional theory(DFT)calculations were also performed to further understand the role FEC in the poly(DOL)-FEC electrolytes.This work broadens the application of in-situ prepared poly(DOL)electrolytes to sodium storage and demonstrates the crucial role of FEC in improving the electrochemical performance.
基金National Natural Science Foundation of China,Grant/Award Numbers:21905265,52072322,U1930402,61974042National Science Foundation,Civil,Mechanical and Manufacturing Innovation,Grant/Award Number:1911905+3 种基金Fundamental Research Funds for the Central Universities,Grant/Award Number:WK2060140026Department of Science and Technology of Sichuan Province,Grant/Award Numbers:2019‐GH02‐00052‐HZ,2019YFG0220Scientific and Technological Innovation Foundation of Shunde Graduate School,Grant/Award Number:BK19BE024National Key Research and Development Program of China,Grant/Award Number:2017YFA0303403。
文摘A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.
基金This research was funded by the National Key Research&Development Program(Grant No.2017YFC0703500).
文摘Bamboo is a renewable natural building material with good mechanical properties.However,due to the heterogeneity and anisotropy of bamboo stalk,a large amount of material performance testing costs are required in engineering applications.In this work,longitudinal compression,bending,longitudinal shear,longitudinal tensile,transverse compression and transverse tensile tests of bamboo materials are conducted,considering the influence of the bamboo nodes.The mechanical properties of the whole bamboo stalk with the wall thickness and outer circumference are explored.Through univariate and multiple regression analysis,the relationship between mechanical properties and wall thickness and perimeter is fitted,and the conversion parameters between different mechanical properties are derived.The research results show that the transverse compressive strength of nodal specimen,and transverse tensile strength of nodal and inter-node specimens increase with the increase of wall thickness and outer circumference,but other mechanical properties decrease with the increase of wall thickness and outer circumference.The prediction formula and conversion parameters of bamboo mechanical properties proposed in this research have high applicability and accuracy.Moreover,this research can provide references for the evaluation of bamboo performance and saving test costs.
基金This work was supported by the National Natural Science Foundation of China under grant number 61471055European Horizon 2020 INPUT project“In-Network Programmability for next-generation personal Cloud service support”,www.input-project.eu,under grant agreement number 644672.
文摘The combination of traditional processors and Field Programmable Gate Arrays(FPGA)is shaping the future networking platform for intensive computation in resource-constrained networks and devices.These networks present two key challenges of security and resource limitations.Lightweight ciphers are suitable to provide data security in such constrained environments.Implementing the lightweight PRESENT encryption algorithm in a reconfigurable platform(FPGAs)can offer secure communication service and flexibility.This paper presents hardware acceleration of security primitives in SDN using NETFPGA-10G.We implement an efficient design of the PRESENT algorithm for faster,smaller and lower power consumption hardware circuit using Verilog.We evaluate the performance of the hardware and software implementations of PRESENT.Experimental results prove that the proposed hardware design is a viable option for use in resource constrained devices in future networks and their applications.
基金supported in part by the Jiangsu Natural Science Foundation of China under Grant BK20180013in part by the Shenzhen Science and Technology Innovation Committee(STIC)under Grant JCYJ20180306174439784.
文摘The pulse-width-modulated(PWM)current-source converters(CSCs)fed electric machine systems can be considered as a type of high reliability energy conversion systems,since they work with the long-life DC-link inductor and offer high fault-tolerant capability for short-circuit faults.Besides,they provide motor friendly waveforms and four-quadrant operation ability.Therefore,they are suitable for high-power applications of fans,pumps,compressors and wind power generation.The purpose of this paper is to comprehensively review recent developments of key technologies on modulation and control of high-power(HP)PWM-CSC fed electric machines systems,including reduction of low-order current harmonics,suppression of inductor–capacitor(LC)resonance,mitigation of common-mode voltage(CMV)and control of modular PWM-CSC fed systems.In particular,recent work on the overlapping effects during commutation,LC resonance suppression under fault-tolerant operation and collaboration of modular PMW-CSCs are described.Both theoretical analysis and some results in simulations and experiments are presented.Finally,a brief discussion regarding the future trend of the HP CSC fed electric machines systems is presented.
文摘Since the development of organic food,to a great extent,depends on the needs of consumers,the studies on the consumer behavior of organic food would have far-reaching significance to the development of the whole organic food industry. The recent studies in this field mainly include the following four aspects: the consumers' recognition of organic food; the consumers' attitude towards organic food; the consumers' purchase of organic food; the consumers' willingness to pay. The paper would review the recent domestic and foreign studies on the four aspects mentioned above,aiming to provide references to the researches in this field.
文摘Systematically analyze the composition of post-marketing adverse drug reaction data and the open mode in the EU, and summarize its characteristics. EU post-marketing ADR data is open to six categories of stakeholders: EMA, EC, medicines regulatory authorities in EEA member states, healthcare professionals and the public, Marketing Authorization Holders, academia, WHO and medicines regulatory authorities in third countries. The EU has implemented hierarchical opening for ADRs, with different levels containing different data and facing different stakeholders. Openness is divided into active and passive openness. In opening up data, the EU complies with relevant personal data protection laws to protect the privacy of individuals. The EU’s post-marketing adverse drug reaction data openness is characterized by a combination of data openness and privacy protection, active and passive openness, and a hierarchy of data openness. It is hoped that this can provide a reference for the opening up of post-marketing adverse drug reaction data in China.
基金the National Key R&D Program of China(2018YFC1200400)the research and innovation project for College Graduates of Jiangsu Province(KYLX18_0957).
文摘Brachymeria lasus Walker is a solitary endoparasitoid that attacks the pupae of a wide range of lepidopteran hosts,including an important invasive species,the fall webworm(Hyphantria cunea Drury).We studied the relationship between temperature and development of B.lasus from egg to adult hatching.The results show a decrease in parasitoid development time from 34.4 days at 18°C to 10.6 days at 32°C.The minimum threshold temperature of B.lasus was 13.2°C±1.7°C,and the eff ective accumulated temperature was 210.3±28.7 degree days.These results provide a basis for optimizing the production of this parasitoid.In addition,the eff ects of host size on off spring performance of B.lasus were investigated under laboratory conditions.Off spring longevity,size,and percentage of females were positively correlated with host size.Female off spring are larger and live longer than males.Furthermore,this research showed that parasitoid adults successfully emerged from approximately 27.9%of pupae.However,eclosion or hatching of H.cunea decreased dramatically,which may be due to damage caused by female B.lasus when testing hosts with their ovipositors or by feeding on them.The results suggest that B.lasus has the potential to become an effi cient natural enemy for controlling H.cunea.
基金Supported by Technology Project of Yunnan Tobacco Monopoly Bureau(201-5YN25)
文摘Using the method in Biodiversity Risk and Opportunity Assessment Handbook of British American Tobacco Biodiversity Partnership,we assess biodiversity risks and opportunities in BAT and China's cooperative tobacco-growing areas. The assessment results indicate that there are 8 risks and 1 opportunity. Action and monitoring plans have been made for medium and high risks as well as opportunity,to reduce impact on biodiversity.
基金Wu Jie-ping Medical Foundation (No. 320.6720.0501)Shenzhen Science Technology Foundation (No. 200404093)
文摘Objective: To investigate the change of ATM phosphorylation in HepG2 cells and its effect on HepG2 cell survival under a continuous low dose-rate irradiation. Methods: HepG2 cells were exposed to equivalent doses of irradiation deliv- ered at either a continuous low dose-rate (7.76 cGy/h) or a high dose-rate (4500 cGy/h). The ATM phosphorylated proteins and surviving fraction of HepG2 cell after low dose-rate irradiation were compared with that after equivalent doses of high dose-rate irradiation. Results: The phosphorylation of ATM protein was maximal at 0.5 Gy irradiation delivered at either a high dose-rate or a continuous low dose-rate. As the radiation dose increased, the phosphorylation of ATM protein decreased under continuous low dose-rate irradiation. However, the phosphorylation of ATM protein was remained stable under high dose-rate irradiation. When the phosphorylation of ATM protein under continuous low dose-rate irradiation was equal to that under high dose-rate irradiation, there was no significant difference in the surviving fraction of HepG2 cells between two ir- radiation methods (P > 0.05). When the phosphorylation of ATM protein significantly decreased after continuous low dose-rate irradiation compared with that after high dose-rate irradiation, increased amounts of cell killing was found in low dose-rate irradiation (P < 0.01). Conclusion: Continuous low dose-rate irradiation increases HepG2 cells radiosensitivity compared with high dose-rate irradiation. The increased amounts of cell killing following continuous low dose-rate exposures are associated with reduced ATM phosphorylated protein.
基金Supported by Young Start-up Funding of Jilin Agricultural University(201229)Key National Risk Assessment Project for the Quality and Safety of Agricultural Products(GJFP2014010)
文摘This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system,this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.
文摘Being controlled by the gas content of the reservoir, the productivity of CBM well is also mainly determined by its engineering quality and the physical property of the reservoir. In Dafosi mine field, 22 vertical wells from the “26 + 1” CBM wells project that was implemented since 2014 showed great difference in productivity after fracturing construction. With the consistent geological condition of coal reservoirs, fracturing construction parameters are suggested as the priority factor that controlling the well productivity. In this study, being combined with historical production and geological data, an optimized designation of fracturing construction parameters was established based on systematically comparative analysis of construction parameters such as discharge, the total volume of fracturing fluid, the quality of sand, sand ratio, which provides engineering basis for further fracturing construction of CBM wells.
基金supported by the National Natural Science Foundation of China(Nos.52073214 and 22075211)Guangxi Natural Science Fund for Distinguished Young Scholars(No.2024GXNSFFA010008).
文摘Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention.Herein we construct the well-defined Mn single-atom(MnSA)catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions(CO_(2)RR)and oxygen reduction reactions(ORR).MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90%at-0.9 V for CO_(2)RR and higher H_(2)O_(2)yield from 0.1 to 0.6 V with excellent ORR activity.Density functional theory(DFT)calculations based on constant potential models were performed to study the mechanism of MnSA on CO_(2)RR.The thermodynamic energy barrier of CO_(2)RR is lowest at-0.9 V vs.reversible hydrogen electrode(RHE).Similar DFT calculations on the H_(2)O_(2)yield of ORR showed that the H_(2)O_(2)yield at 0.2 V was higher.This study provides a reasonable explanation for the role of electrode potential micro-environments.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金supported by National Natural Science Foundation of China(No.22275041No.21774028,No.21574030)+4 种基金Science and Technology Department of Guizhou Province&Guizhou University Joint FundScience and Technology Department of Guizhou Province(Natural Science Key Fund ZK[2021]023Platform&Talents[2016]5652,[2017]5788,[2018]5781,and[2019]5607)Introduced Talent Research Project of Guizhou University([2022]16)LETSGrp2020042402 and Basic research project of Guizhou University([2023]01).
文摘Phenolation is one of the effective strategies to synthesize lignin-based polyphenols,improve lignin’s properties,and extend its value-added applications in biological,medicinal and cosmetic fields.Herein,by taking the structural feature advantage of lignin,an effective and green strategy was developed to molecularly engineer lignin into a robust lignin-3-(2-hydroxyphenyl)propionate ester(LPPE)derivative via a transesterification reaction between 3,4-dihydrocoumarin(DHC)and the aliphatic hydroxyls in lignin under organocatalysis.The strategy is optimized and the novel derivative was systematically characterized by ^(1)H,^(13)C and ^(31)P nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy.The findings indicated that the successful introduction of 3-(2-hydroxyphenyl)propionate groups using a OH groups/DHC/organic base mo-lar ratio of 1꞉1꞉0.3 at 120℃ for 6 h increased the content of phenolic hydroxyl groups from 1.7931 to 3.0179 mmol/g,and the LPPE exhibited excellent ultraviolet-absorbing and antioxidant per-formance with up to 90%free radical scavenging activity within 20 min using 5 mg/mL of LPPE.In addition,good biocompatibility and a high Sun protection factor(SPF)value of 40.9 were achieved at 5%(w)dosage of LPPE in the cream,indicating its significant application potential in sunscreen.
基金This work was supported by grants from the Key Development Program of the Children's Hospital of Fudan University(grant no.EK2022ZX05).
文摘Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with AGE in Shanghai from 2018 to 2021.The overall detection rate of NoV was 11.9%(181/1545),with annual detection rates of 9.4%(36/381),13.6%(29/213),5.8%(13/226)and 14.2%(103/725),respectively.Of note,the prevalence of NoV in 2020 was significantly lower than that in 2018-2019(10.9%,65/594)(P=0.023)and 2021(14.2%,103/725)(P=0.000).The 181 NoV strains identified in this study were classified into the GI group(1.1%,2/181),GII group(98.3%,178/181)and GIX group(0.6%,1/181)according to the VP1 gene.The most common NoV VP1 genotype was GII.4 Sydney_2012(63.5%,115/181),followed by GII.3(19.9%,36/181)and GII.2(9.4%,17/181).For P genotypes,174 strains were sequenced successfully according to the RdRp gene,and the predominant genotype was GII.P16(44.8%,78/174),followed by GII.P31(25.9%,45/174)and GII.P12(21.3%,37/174).Among the 174 cases,GII.4 Sydney_2012[P16](36.8%,64/174)was the dominant genotype,followed by GII.4 Sydney_2012[P31](25.3%,44/174),GII.3[P12](20.1%,35/174)and GII.2[P16](8.0%,14/174).In particular,the dominant genotypes in Shanghai changed from GII.4 Sydney_2012[P31]in 2018-2019 to GII.4 Sydney_2012[P16]in 2020-2021.This is the first report to describe the epidemiological changes in NoV infection before and during the COVID-19 pandemic in Shanghai.These data highlight the importance of continuous surveillance for NoV in children with AGE in Shanghai.
