Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded...Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).展开更多
As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple ...As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple output(MIMO)technique to improve its capacity and coverage.Thus,testing new functions of the 5G MIMO system accurately and ef-ficiently,including beamforming(beam-tracking with movement)and multiple-user(MU)multiplexing,is a challenging task.This paper tries to construct a lab-oratorial hardware and conduct equipment-controlled field testing.Firstly,the testing scheme is presented,which is composed of the framework,the channel models and the validation methods.Then,the channel model principles are explained in detail due to its di-rect influence on the testing accuracy.Specifically,we utilize the spatial consistency and the multi-link cor-relation properties to emulate the high-speed dynamic time-varying(HDT)and the multiple-cell(MC)-MU-MIMO channels.Finally,the above testing scheme is verified in a Shanghai 5G field experiment with the practical commercial equipment and the channel em-ulator.The results show that the 5G new functions are tested accurately and efficiently by switching the channel emulation configurations.展开更多
With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzin...With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzing representative ap-plication scenarios to clarify the core requirements of the low-altitude economy for modern ISAC net-works.By investigating the distinctive characteris-tics of ISAC networks in low-altitude environments,it presents a comprehensive analysis of key challenges and identifies four major issues:challenges in pre-cise target detection,interference management,in-consistent sensing and communication coverage,and the complexity of air-ground coordination and han-dover.Based on fundamental theories and principles,the paper proposes corresponding solutions,encom-passing advanced technologies for precise target de-tection and recognition,high-reliability networked de-tection,robust interference management,and seamless air-ground collaboration.These solutions aim to es-tablish a solid foundation for the future development of intelligent low-altitude networks and ensure effec-tive support for emerging applications.展开更多
Extremely large-scale multiple-input multiple-output(XL-MIMO)is regarded as a promis-ing technology for next-generation communication systems.However,this will expand the near-field(NF)range,rendering more users more ...Extremely large-scale multiple-input multiple-output(XL-MIMO)is regarded as a promis-ing technology for next-generation communication systems.However,this will expand the near-field(NF)range,rendering more users more likely to be located in the NF region.In this paper,we aim to answer two questions:What are the new characteristics of the NF channel?Is it necessary to develop new transciver techniques to maintain system performance within the NF region?To this end,we first review current NF channel models and analyze the differences between the existing 3GPP TR 38.901 channel model and the NF channel model,including the spherical wavefront and spatially non-stationarity.Then,we provide ex-amples on how these differences affect the XL-MIMO system performance in terms of beamforming gain and achievable rate.Simulation results demonstrate that,when using far-field(FF)technique under the NF channel,the maximum normalized beam gain loss is less than 3 dB for most users in the NF region de-fined by Rayleigh distance.Moreover,the achievable rate loss of beam training is less than 3%compared to that realized by NF technique.Finally,we demonstrate the necessity of employing NF transceiver techniques based on simulation results.展开更多
With the widespread adoption of lithium-ion batteries(LIBs),safety concerns associated with flammable organic elec-trolytes have become increasingly critical.Solid-state lithium batteries(SSLBs),with enhanced safety a...With the widespread adoption of lithium-ion batteries(LIBs),safety concerns associated with flammable organic elec-trolytes have become increasingly critical.Solid-state lithium batteries(SSLBs),with enhanced safety and higher energy density potential,are regarded as a promising next-generation energy storage technology.However,the practical appli-cation of solid-state electrolytes(SSEs)remains hindered by several challenges,including low Li+ion conductivity,poor interfacial compatibility with electrodes,unfavorable mechanical properties and difficulties in scalable manufacturing.This review systematically examines recent progress in SSEs,including inorganic types(oxides,sulfides,halides),organic types(polymers,plastic crystals,poly(ionic liquids)(PILs)),and the emerging class of soft solid-state electrolytes(S3Es),especially those based on“rigid-flexible synergy”composites and“Li+-desolvation”mechanism using porous frameworks.Critical assessment reveals that single-component SSEs face inherent limitations that are difficult to be fully overcome through compositional and structural modification alone.In contrast,S3Es integrate the strength of complementary components to achieve a balanced and synergic enhancement in electrochemical properties(e.g.,ionic conductivity and stability window),mechanical integrity,and processability,showing great promise as next-generation SSEs.Furthermore,the application-ori-ented challenges and emerging trends in S3E research are outlined,aiming to provide strategic insights into future develop-ment of high-performance SSEs.展开更多
Solid-state polymer sodium batteries(SPSBs)are promising candidates for achieving higher energy density and safe energy storage.However,interface issues between oxide cathode and solid-state polymer electrolyte are a ...Solid-state polymer sodium batteries(SPSBs)are promising candidates for achieving higher energy density and safe energy storage.However,interface issues between oxide cathode and solid-state polymer electrolyte are a great challenge for their commercial application.In contrast,soft sulfur-based materials feature better interface contact and chemical compatibility.Herein,an interfacial compatible polysulfide Ti_(4)P_(8)S_(29) with robust Ti-S bonding and a highly active P-S unit is tailored as a high-performance cathode for SPSBs.The Ti_(4)P_(8)S_(29) cathode possesses a three-dimensional channel structure for offering ample Na+diffusion pathways.The assembled poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)-based SPSBs deliver a discharge capacity of 136 mAh·g^(-1)at 0.5C after 200 cycles.Furthermore,a discharge capacity of 88 mAh·g^(-1)is retained after 600 cycles at a high rate of 2C,surpassing many cathode materials in SPSBs.A dual-site redox of Ti^(4+)/Ti^(3+)and S^(-)/S^(2-)is verified by X-ray photoelectron spectroscopy(XPS)and cyclic voltammetry(CV)tests.Interestingly,a refined locally-ordered amorphous structure is unveiled by in situ and ex situ characterizations.The as-formed electrode structure with lots of open channels and isotropic properties are more beneficial for ion diffusion on the interface of electrode and solid-state polymer electrolytes(SPEs),leading to faster Na+diffusion kinetics.This work proposes a strategy of modulating open-channel to boost conversion kinetics in polysulfide cathode and opens a new pathway for designing high-performance SPSBs.展开更多
Reward or stress,which exists extensively,causes resilient emotional fluctuations under common situations.However,reward or stress is a typical trigger for manic or depressive episodes of bipolar disorder(BD),which is...Reward or stress,which exists extensively,causes resilient emotional fluctuations under common situations.However,reward or stress is a typical trigger for manic or depressive episodes of bipolar disorder(BD),which is corroborated by psychological theory,biological findings,and psychosocial treatment approaches[1,2].During an episode of BD,the affective aberration can be persistent and switchable,accompanied by opposite constellations of cognitive and psychomotor symptoms.Characterized by uncontrollable mood ranging in severity,duration,and polarity,to disentangle the pathophysiology mechanism of BD is to delineate the mystery of affective fluctuations driven by reward or stress.展开更多
Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in mariti...Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in maritime shipping using the levelized cost of energy methodology.It includes a detailed comparative analysis based on essential criteria and sensitivity assessments to highlight the economic impacts of technological advancements.Key factors influencing total costs include fuel costs,carbon pricing,and energy demands for carbon capture.The findings reveal that methanol is more cost-effective than heavy fuel oil(HFO)when priced below 3000 CNY/t,assuming HFO costs 4400 CNY/t.Additionally,methanol with post-combustion carbon capture is less expensive than pre-combustion carbon capture.When carbon prices rise above 480 CNY/t,carbon capture technologies prove more economical than purchasing carbon emission allowances for HFO and liquefied natural gas.Enhanc-ing the use of exhaust gas waste heat is recommended for cost savings.Post-combustion carbon capture also shows greater efficiency,requiring about 1.1 GJ/t less energy than pre-combustion methods,leading to lower overall costs.Future research should focus on market mechanisms to stabilize fuel prices and develop less energy-intensive carbon capture technologies.This study offers critical insights into effective decarbonization strategies for advancing global maritime trade in the present and future.展开更多
Type 2 diabetes mellitus has central complications:Diabetes,a metabolic disorder primarily characterized by hyperglycemia due to insufficient insulin secretion,or impaired insulin signaling,has significant central com...Type 2 diabetes mellitus has central complications:Diabetes,a metabolic disorder primarily characterized by hyperglycemia due to insufficient insulin secretion,or impaired insulin signaling,has significant central complications.Type 2 diabetes mellitus(T2DM),the most prevalent type of diabetes,affects more than 38 million individuals in the United States(approximately 1 in 10)and is defined by chronic hyperglycemia and insulin resistance,which refers to a reduced cellular response to insulin.展开更多
High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environm...High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environments,tunable electronic structures,abundant unsaturated active sites,and dynamic structural reassembly—collectively enhance electrochemical activity and durability under operating conditions.This review summarizes recent advances in HEACs for hydrogen evolution,oxygen evolution,and overall water splitting,highlighting their disorder-driven advantages over crystalline counterparts.Catalytic performance benchmarks are presented,and mechanistic insights are discussed,focusing on how multimetallic synergy,amorphization effect,and in‐situ reconstruction cooperatively regulate reaction pathways.These insights provide guidance for the rational design of next‐generation amorphous high‐entropy electrocatalysts with improved efficiency and durability.展开更多
The microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states were studied.The results reveal that island compounds at the grain boundaries of the as-cast alloys m...The microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states were studied.The results reveal that island compounds at the grain boundaries of the as-cast alloys mainly were Mg24Y5,Mg41Nd5,and Mg5Gd phases.After homogenization at 808 K for 24 h,the distribution of the island compounds became discrete and Mg5Gd phases mostly decomposed and dissolved.With hot extrusion,the grain size was refined to about 20 μm on average,and both the strength and elongation were greatly improved.After ageing at 523 K for 5 h,the strength of different extruded alloys largely increased but the elongation decreased.With the increase of neodymium content,the strength of the alloys at different states increased.The content of neodymium element had an obvious effect on the elongation of the designed alloys.In the designed alloys,the Mg-5Y-5Gd-2.2Nd-0.5Zr alloy exhibited the best combination properties and its ultimate tensile strength,yield strength,and elongation could reach 380 MPa,285 MPa,and 9.0%,respectively.展开更多
The current research of configurable product disassemblability focuses on disassemblability evaluation and disassembly sequence planning. Little work has been done on quantitative analysis of configurable product disa...The current research of configurable product disassemblability focuses on disassemblability evaluation and disassembly sequence planning. Little work has been done on quantitative analysis of configurable product disassemblability. The disassemblability modeling technology for configurable product based on disassembly constraint relation weighted design structure matrix （DSM） is proposed. Major factors affecting the disassemblability of configurable product are analyzed, and the disassembling degrees between components in configurable product are obtained by calculating disassembly entropies such as joint type, joint quantity, disassembly path, disassembly accessibility and material compatibility. The disassembly constraint relation weighted DSM of configurable product is constructed and configuration modules are formed by matrix decomposition and tearing operations. The disassembly constraint relation in configuration modules is strong coupling, and the disassembly constraint relation between modules is weak coupling, and the disassemblability configuration model is constructed based on configuration module. Finally, taking a hydraulic forging press as an example, the decomposed weak coupling components are used as configuration modules alone, components with a strong coupling are aggregated into configuration modules, and the disassembly sequence of components inside configuration modules is optimized by tearing operation. A disassemblability configuration model of the hydraulic forging press is constructed. By researching the disassemblability modeling technology of product configuration design based on disassembly constraint relation weighted DSM, the disassembly property in maintenance, recycling and reuse of configurable product are optimized.展开更多
Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry ...Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry preparation. In this paper, slurry of AZ31 alloy was produced by a novel rheocast process known as self-inoculation method （SIM）. Interrupted quenching technology was applied to investigate the primary a-Mg evolution during continuous cooling and isothermal holding. Results indicate that the initial microstructure of slurry produced by SIM is a mixture of irregular grains, which becomes ideally globular when the slurry slowly cools to 620 ~C and isothermally held for at least 30 s. The local solute diffusion leads to dendritic fragmentation and forms separated particles. During prolonged holding, the particle surface gradually becomes smooth because of protuberance melting and groove advancement. Coarsening of a-Mg grains in isothermal holding was analyzed using Lifshitz-Slyozov-Wagner theory. Results suggest that coalescence is most likely the dominant coarsening mechanism in the early stage while Ostwald ripening tends to be the principal one later. The EDS results indicate that a longer holding time leads to AI solute element segregation at the grain boundaries, but Zn distribution within liquid matrix has no obvious change.展开更多
Use of metallic Li anode raises serious concerns on the safety and operational performance of Li-S batteries due to uncontrolled hazard of Li dendrite formation, which is difficultly eliminated as long as the metallic...Use of metallic Li anode raises serious concerns on the safety and operational performance of Li-S batteries due to uncontrolled hazard of Li dendrite formation, which is difficultly eliminated as long as the metallic Li exists in the cells. Pairing lithium sulfide (Li2S) cathode with currently available metallic Lifree high-capacity anodes offers an alternative solution to this challenge. However, the performance of Li2S cathode is primarily restricted by high activation barrier upon initial charge, low active mass utilization and sluggish redox kinetics. Herein, a MXene-induced multifunctional collaborative interface is proposed to afford superb activity towards redox solid-liquid/liquid-liquid phase transformation, strong chemisorption, high conductivity and fast ionic/charge transport in high Li2S loading cathode. Applying collaborative interface effectively reduces initial voltage barrier of Li2S activation and regulates the kinetic behavior of redox polysulfide conversion. Therefore, stable operation of additive-free Li2S cathode with high areal capacities at high Li2S loading up to 9 mg cm^-2 can be achieved with less sacrifice of high capacity and rate capability in Li-S batteries. Rechargeable metallic Li-free batteries are successfully constructed by pairing this high-performance Li2S cathode with high-capacity metal oxide anodes, which delivers superior energy density to current Li-ion batteries.展开更多
Sulfur deposition in the formation, induced by a reduction in the solubility of the sulfur in the gas phase, may significantly reduce the inflow performance of sour gas wells and some wells in sour gas reservoirs have...Sulfur deposition in the formation, induced by a reduction in the solubility of the sulfur in the gas phase, may significantly reduce the inflow performance of sour gas wells and some wells in sour gas reservoirs have even become completely plugged with deposited sulfur within several months. Accurate prediction and effective management of sulfur deposition are crucial to the economic viability of sour gas reservoirs. In this paper, a dynamic flow experiment was carried out to investigate formation damage resulting from sulfur deposition using an improved experimental method. The core sample was extracted from the producing interval of the LG2 well, LG gas field in the Sichuan Basin. The experimental temperature was 26 °C and the initial pressure was 19 MPa. The displacement pressure continuously decreased from 19 to 10 MPa, and the depletion process lasted 15 days. Then the core was removed and dried. The core mass and core permeability were measured before and after experiments. Experimental results indicated that the core mass increased from 48.372 g before experiment to 48.386 g afterwards, while the core permeability reduced from 0.726 to 0.608 md during the experiment. Then the core was analyzed with a scanning electron microscope (SEM) and energy-dispersive X-ray mapping. The deposition pattern and micro-distribution of elemental sulfur was observed and the deposited elemental sulfur distributed as a film around the pore surface.展开更多
An analytical model on the normal perforation of reinforced concrete slabs is constructed. The effect of reinforcing bars is further hybridized in a general three-stage model consisting of initial cratering, tunnellin...An analytical model on the normal perforation of reinforced concrete slabs is constructed. The effect of reinforcing bars is further hybridized in a general three-stage model consisting of initial cratering, tunnelling and shear plugging. Besides three dimensionless numbers, i. e., the impact function I, the geometry function of projectile N and the dimensionless thickness of concrete target X, which are employed to predict the ballistic performance of perforation of concrete slabs, the reinforcement ratio Ps of concrete and the tensile strength fs of reinforcing bars are considered as the other main factors influencing the perforation process. Simpler solutions of ballistic performances of normal perforation of reinforced concrete slabs are formulated. Theoretical predictions agree well with individual published experimental data.展开更多
The polymer-ceramic composite electrolyte is considered as one of promising electrolytes for solid-state battery.However,in previous research,ceramic particles are usually dispersed in polymer matrix and could not for...The polymer-ceramic composite electrolyte is considered as one of promising electrolytes for solid-state battery.However,in previous research,ceramic particles are usually dispersed in polymer matrix and could not form continuous Li+conductive channels.The agglomeration of ceramic particles could also lead to low ionic conductivity and poor interfacial electrode/electrolyte contact.In this paper,self-supported porous Li_(6.4)La_(3) Zr_(1.4)Ta_(0.6)O_(12)(LLZTO) electrolyte is synthesized by gelcasting process,which possesses three-dimensional(3D) interconnected pore channels and relatively high strength.The 1,3-dioxolane(DOL) could penetrate into the porous LLZTO framework for its excellent fluidity.The subsequent in situ polymerization process by thermal treatment could completely fill the internal pores and improve the interfacial contact with electrode.The resulting 3D composite electrolyte with dual continuous Li+transport channels in ceramic and polymer components exhibits high ionic conductivity of 2.8 × 10^(-4) S·cm^(-1) at room temperature and low Li/electrolyte interfacial resistance of 94 Ω·cm^(2) at 40 ℃.The corresponding Li/Li symmetric cell delivers stable voltage profiles for over 600 h under 0.1 and 0.2 mA·cm^(-2).The solid-state Li/LiFePO_(4) battery shows superior rate and cycling performance under 0.1 C and 0.2 C.This work guides the preparation of composite electrolyte with dual continuous Li+conductive paths as well as high ceramic ratio and interface modification strategy for solid-state Li metal battery.展开更多
Phyllostachys praecox is a bamboo species cultivated for edible shoots under intensive management.However,the potential pollution risk of heavy metals in bamboo soils is not clear under the intensive management for a ...Phyllostachys praecox is a bamboo species cultivated for edible shoots under intensive management.However,the potential pollution risk of heavy metals in bamboo soils is not clear under the intensive management for a long term.The objective of this study was to evaluate the effect of cultivation time on soil heavy metal accumulation and bioavailability in bamboo stands subjected to intensive management.Soil samples were collected from a chronosequence of bamboo stands which had been cultivated for 0,1,2,4,8,and 10 years in Lin’an,Zhejiang Province of China.Eight heavy metals(Cu,Zn,Pb,Ni,Cr,Cd,As,and Hg)present in the soil were selected,and their potential pollution risk was evaluated by chemical speciation analysis.Possible heavy metal sources were explored using multivariate and cluster analysis.Our results showed that Zn,Cu,Hg,and Cd contents in the soil increased with the cultivation time,while Ni,Cr,Pb,and As levels were similar among all stands.Furthermore,the bioavailabilities of all analyzed heavy metals increased with the cultivation time.Multivariate and cluster analysis showed that sources of Ni,Cr,Pb,and As were likely lithogenic in origin,whereas input of Zn,Cu,Hg,and Cd was mainly due to cultivation practices.Current bamboo management strategies raised the potential risks of heavy metal pollution in bamboo shoots in the long term.Soil acidification in P.praecox stands induced by intensive cultivation should be controlled since it stimulated and improved the bioavailability of heavy metals.Appropriate management strategies should thus be adopted to ensure safe and sustainable production of bamboo shoots.展开更多
A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles....A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles. The structure and formation mechanism of the hollow spheres were investigated in detail. The control mechanism of shell thickness was also discussed. The results indicated that the shell thickness and coarseness of the synthesized core-shell hematite hollow spheres could be tuned simply by the surface carboxyl content of the P（St-co-AA） particles. This method provided a new approach for the structure control in the preparation of hollow spheres. A Brunauer-Emmett-Teller （BET） test shows that the prepared hollow spheres have large surface areas which were decreased along with the increase of the diameter. The magnetic properties of the as-obtained hematite hollow spheres were investigated. The result showed that the coercivity and saturated magnetization were increased along with the increase of the shell thickness, and the remanent magnetization was increased along with the decrease of the diameter.展开更多
基金supported by the National Key Research and Development Program of China(2019YFA0905100)the National Natural Science Foundation of China(21991102,22378227).
文摘Constructing a framework carrier to stabilize protein conformation,induce high embedding efficiency,and acquire low mass-transfer resistance is an urgent issue in the development of immobilized enzymes.Hydrogen-bonded organic frameworks(HOFs)have promising application potential for embedding enzymes.In fact,no metal involvement is required,and HOFs exhibit superior biocompatibility,and free access to substrates in mesoporous channels.Herein,a facile in situ growth approach was proposed for the self-assembly of alcohol dehydrogenase encapsulated in HOF.The micron-scale bio-catalytic composite was rapidly synthesized under mild conditions(aqueous phase and ambient temperature)with a controllable embedding rate.The high crystallinity and periodic arrangement channels of HOF were preserved at a high enzyme encapsulation efficiency of 59%.This bio-composite improved the tolerance of the enzyme to the acid-base environment and retained 81%of its initial activity after five cycles of batch hydrogenation involving NADH coenzyme.Based on this controllably synthesized bio-catalytic material and a common lipase,we further developed a two-stage cascade microchemical system and achieved the continuous production of chiral hydroxybutyric acid(R-3-HBA).
基金supported in part by National Natural Science Foundation of China under Grant 62201087,Grant 62525101,in part by the National Key R&D Program of China under Grant 2023YFB2904803in part by the Guangdong Major Project of Basic and Applied Basic Research under Grant 2023B0303000001+1 种基金in part by the Natural Science Foundation of Beijing-Xiaomi Innovation Joint Foundation under Grant L243002in part by the Beijing University of Posts and Telecommunications-China Mobile Research Institute Joint Institute.
文摘As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple output(MIMO)technique to improve its capacity and coverage.Thus,testing new functions of the 5G MIMO system accurately and ef-ficiently,including beamforming(beam-tracking with movement)and multiple-user(MU)multiplexing,is a challenging task.This paper tries to construct a lab-oratorial hardware and conduct equipment-controlled field testing.Firstly,the testing scheme is presented,which is composed of the framework,the channel models and the validation methods.Then,the channel model principles are explained in detail due to its di-rect influence on the testing accuracy.Specifically,we utilize the spatial consistency and the multi-link cor-relation properties to emulate the high-speed dynamic time-varying(HDT)and the multiple-cell(MC)-MU-MIMO channels.Finally,the above testing scheme is verified in a Shanghai 5G field experiment with the practical commercial equipment and the channel em-ulator.The results show that the 5G new functions are tested accurately and efficiently by switching the channel emulation configurations.
基金supported by National Science and Technology Major Project of China(Project Number:2024ZD1300100)Fundamental Research Funds for the central universities(2024RC02)+1 种基金National Natural Science Foundation of China(62401077,62321001)Beijing Municipal Natural Science Foundation(L232003)。
文摘With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzing representative ap-plication scenarios to clarify the core requirements of the low-altitude economy for modern ISAC net-works.By investigating the distinctive characteris-tics of ISAC networks in low-altitude environments,it presents a comprehensive analysis of key challenges and identifies four major issues:challenges in pre-cise target detection,interference management,in-consistent sensing and communication coverage,and the complexity of air-ground coordination and han-dover.Based on fundamental theories and principles,the paper proposes corresponding solutions,encom-passing advanced technologies for precise target de-tection and recognition,high-reliability networked de-tection,robust interference management,and seamless air-ground collaboration.These solutions aim to es-tablish a solid foundation for the future development of intelligent low-altitude networks and ensure effec-tive support for emerging applications.
基金supported by the National Key R&D Program of China(No.2023YFB2904803)the Beijing Natural Science Foundation(L243002),the National Natural Science Foundation of China(No.62341128)+2 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000001)the National Natural Science Foundation of China(No.62201086)Beijing University of Posts and Telecommunications-China Mobile Research Institute Joint Innovation Center.
文摘Extremely large-scale multiple-input multiple-output(XL-MIMO)is regarded as a promis-ing technology for next-generation communication systems.However,this will expand the near-field(NF)range,rendering more users more likely to be located in the NF region.In this paper,we aim to answer two questions:What are the new characteristics of the NF channel?Is it necessary to develop new transciver techniques to maintain system performance within the NF region?To this end,we first review current NF channel models and analyze the differences between the existing 3GPP TR 38.901 channel model and the NF channel model,including the spherical wavefront and spatially non-stationarity.Then,we provide ex-amples on how these differences affect the XL-MIMO system performance in terms of beamforming gain and achievable rate.Simulation results demonstrate that,when using far-field(FF)technique under the NF channel,the maximum normalized beam gain loss is less than 3 dB for most users in the NF region de-fined by Rayleigh distance.Moreover,the achievable rate loss of beam training is less than 3%compared to that realized by NF technique.Finally,we demonstrate the necessity of employing NF transceiver techniques based on simulation results.
基金the financial support from the National Key R&D Program of China (Grant No. 2021YFB3800300)the supports from National Key R&D Program of China (Grant No. 2022YFB3807700)+6 种基金the National Natural Science Foundation of China (Grant No. U20A20248)the supports from the National Natural Science Foundation of China (Grant Nos. W2441017, 22409103)the “Innovation Yongjiang 2035” Key R&D Program (Grant Nos. 2024Z040, 2025Z063)the National Key R&D Program of China (Grant No. 2023YFC2812700)the Natural Science Foundation of Shandong Province (Grant No. ZR2024YQ008)funding supports from the National Key R&D Program of China (Grant No. 2021YFB3800300)science and technology innovation fund for emission peak and carbon neutrality of Jiangsu province (Grant Nos. BK20220034, BK20231512)。
文摘With the widespread adoption of lithium-ion batteries(LIBs),safety concerns associated with flammable organic elec-trolytes have become increasingly critical.Solid-state lithium batteries(SSLBs),with enhanced safety and higher energy density potential,are regarded as a promising next-generation energy storage technology.However,the practical appli-cation of solid-state electrolytes(SSEs)remains hindered by several challenges,including low Li+ion conductivity,poor interfacial compatibility with electrodes,unfavorable mechanical properties and difficulties in scalable manufacturing.This review systematically examines recent progress in SSEs,including inorganic types(oxides,sulfides,halides),organic types(polymers,plastic crystals,poly(ionic liquids)(PILs)),and the emerging class of soft solid-state electrolytes(S3Es),especially those based on“rigid-flexible synergy”composites and“Li+-desolvation”mechanism using porous frameworks.Critical assessment reveals that single-component SSEs face inherent limitations that are difficult to be fully overcome through compositional and structural modification alone.In contrast,S3Es integrate the strength of complementary components to achieve a balanced and synergic enhancement in electrochemical properties(e.g.,ionic conductivity and stability window),mechanical integrity,and processability,showing great promise as next-generation SSEs.Furthermore,the application-ori-ented challenges and emerging trends in S3E research are outlined,aiming to provide strategic insights into future develop-ment of high-performance SSEs.
基金supported by the National Key Research and Development Program of China(No.2019YFA0210600)the National Natural Science Foundation of China(Nos.51922103 and 51972326)+1 种基金the Natural Science Foundation of Jiangxi Province(Nos.20224BAB204002 and GJJ211320)Jingdezhen Science and Technology Bureau(No.20212GYZD009-15)。
文摘Solid-state polymer sodium batteries(SPSBs)are promising candidates for achieving higher energy density and safe energy storage.However,interface issues between oxide cathode and solid-state polymer electrolyte are a great challenge for their commercial application.In contrast,soft sulfur-based materials feature better interface contact and chemical compatibility.Herein,an interfacial compatible polysulfide Ti_(4)P_(8)S_(29) with robust Ti-S bonding and a highly active P-S unit is tailored as a high-performance cathode for SPSBs.The Ti_(4)P_(8)S_(29) cathode possesses a three-dimensional channel structure for offering ample Na+diffusion pathways.The assembled poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)-based SPSBs deliver a discharge capacity of 136 mAh·g^(-1)at 0.5C after 200 cycles.Furthermore,a discharge capacity of 88 mAh·g^(-1)is retained after 600 cycles at a high rate of 2C,surpassing many cathode materials in SPSBs.A dual-site redox of Ti^(4+)/Ti^(3+)and S^(-)/S^(2-)is verified by X-ray photoelectron spectroscopy(XPS)and cyclic voltammetry(CV)tests.Interestingly,a refined locally-ordered amorphous structure is unveiled by in situ and ex situ characterizations.The as-formed electrode structure with lots of open channels and isotropic properties are more beneficial for ion diffusion on the interface of electrode and solid-state polymer electrolytes(SPEs),leading to faster Na+diffusion kinetics.This work proposes a strategy of modulating open-channel to boost conversion kinetics in polysulfide cathode and opens a new pathway for designing high-performance SPSBs.
基金supported by the National Key Research and Development Program of China(2023YFC2506200)the Leading Talent of Scientific and Technological Innovation-"Ten Thousand Talents Program"of Zhejiang Province(2021R52016).
文摘Reward or stress,which exists extensively,causes resilient emotional fluctuations under common situations.However,reward or stress is a typical trigger for manic or depressive episodes of bipolar disorder(BD),which is corroborated by psychological theory,biological findings,and psychosocial treatment approaches[1,2].During an episode of BD,the affective aberration can be persistent and switchable,accompanied by opposite constellations of cognitive and psychomotor symptoms.Characterized by uncontrollable mood ranging in severity,duration,and polarity,to disentangle the pathophysiology mechanism of BD is to delineate the mystery of affective fluctuations driven by reward or stress.
基金supported by the National Key R&D Program of China(No.2022YFC3701500)the Key R&D Plan Projects of Zhejiang Province(No.2024SSYS0072)Zhejiang Provincial Natural Science Foundation(No.LDT23E0601).
文摘Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in maritime shipping using the levelized cost of energy methodology.It includes a detailed comparative analysis based on essential criteria and sensitivity assessments to highlight the economic impacts of technological advancements.Key factors influencing total costs include fuel costs,carbon pricing,and energy demands for carbon capture.The findings reveal that methanol is more cost-effective than heavy fuel oil(HFO)when priced below 3000 CNY/t,assuming HFO costs 4400 CNY/t.Additionally,methanol with post-combustion carbon capture is less expensive than pre-combustion carbon capture.When carbon prices rise above 480 CNY/t,carbon capture technologies prove more economical than purchasing carbon emission allowances for HFO and liquefied natural gas.Enhanc-ing the use of exhaust gas waste heat is recommended for cost savings.Post-combustion carbon capture also shows greater efficiency,requiring about 1.1 GJ/t less energy than pre-combustion methods,leading to lower overall costs.Future research should focus on market mechanisms to stabilize fuel prices and develop less energy-intensive carbon capture technologies.This study offers critical insights into effective decarbonization strategies for advancing global maritime trade in the present and future.
基金supported by grants from NIH T32(DK007260,to WC)the Steno North American Fellowship awarded by the Novo Nordisk Foundation(NNF23OC0087108,to WC)+6 种基金STI2030-Major Projects(2021ZD0202700,to HY)the National Natural Science Foundation of China(32241004,to HY)the Natural Science Foundation of Zhejiang Province of China(LR24C090001,to HY)Key R&D Program of Zhejiang Province(2024SSYS0017,to HY)CAMS Innovation Fund for Medical Sciences(2019-12M-5-057,to HY)Fundamental Research Funds for the Central Universities(226-2022-00193,to HY)the Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences(2023-PT310-01,to HY)。
文摘Type 2 diabetes mellitus has central complications:Diabetes,a metabolic disorder primarily characterized by hyperglycemia due to insufficient insulin secretion,or impaired insulin signaling,has significant central complications.Type 2 diabetes mellitus(T2DM),the most prevalent type of diabetes,affects more than 38 million individuals in the United States(approximately 1 in 10)and is defined by chronic hyperglycemia and insulin resistance,which refers to a reduced cellular response to insulin.
基金supported by the Australian Research Council(ARC)Projects(DP220101139,DP220101142,and LP240100542).
文摘High‐entropy amorphous catalysts(HEACs)integrate multielement synergy with structural disorder,making them promising candidates for water splitting.Their distinctive features—including flexible coordination environments,tunable electronic structures,abundant unsaturated active sites,and dynamic structural reassembly—collectively enhance electrochemical activity and durability under operating conditions.This review summarizes recent advances in HEACs for hydrogen evolution,oxygen evolution,and overall water splitting,highlighting their disorder-driven advantages over crystalline counterparts.Catalytic performance benchmarks are presented,and mechanistic insights are discussed,focusing on how multimetallic synergy,amorphization effect,and in‐situ reconstruction cooperatively regulate reaction pathways.These insights provide guidance for the rational design of next‐generation amorphous high‐entropy electrocatalysts with improved efficiency and durability.
基金supported by the National Basic Research Program of China (No. 2007CB613704 and 2007CB613705)
文摘The microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states were studied.The results reveal that island compounds at the grain boundaries of the as-cast alloys mainly were Mg24Y5,Mg41Nd5,and Mg5Gd phases.After homogenization at 808 K for 24 h,the distribution of the island compounds became discrete and Mg5Gd phases mostly decomposed and dissolved.With hot extrusion,the grain size was refined to about 20 μm on average,and both the strength and elongation were greatly improved.After ageing at 523 K for 5 h,the strength of different extruded alloys largely increased but the elongation decreased.With the increase of neodymium content,the strength of the alloys at different states increased.The content of neodymium element had an obvious effect on the elongation of the designed alloys.In the designed alloys,the Mg-5Y-5Gd-2.2Nd-0.5Zr alloy exhibited the best combination properties and its ultimate tensile strength,yield strength,and elongation could reach 380 MPa,285 MPa,and 9.0%,respectively.
基金Supported by National Natural Science Foundation of China(Grant No.51375437)Zhejiang Provincial Natural Science Foundation of China(Grant No.LY12E05019)
文摘The current research of configurable product disassemblability focuses on disassemblability evaluation and disassembly sequence planning. Little work has been done on quantitative analysis of configurable product disassemblability. The disassemblability modeling technology for configurable product based on disassembly constraint relation weighted design structure matrix （DSM） is proposed. Major factors affecting the disassemblability of configurable product are analyzed, and the disassembling degrees between components in configurable product are obtained by calculating disassembly entropies such as joint type, joint quantity, disassembly path, disassembly accessibility and material compatibility. The disassembly constraint relation weighted DSM of configurable product is constructed and configuration modules are formed by matrix decomposition and tearing operations. The disassembly constraint relation in configuration modules is strong coupling, and the disassembly constraint relation between modules is weak coupling, and the disassemblability configuration model is constructed based on configuration module. Finally, taking a hydraulic forging press as an example, the decomposed weak coupling components are used as configuration modules alone, components with a strong coupling are aggregated into configuration modules, and the disassembly sequence of components inside configuration modules is optimized by tearing operation. A disassemblability configuration model of the hydraulic forging press is constructed. By researching the disassemblability modeling technology of product configuration design based on disassembly constraint relation weighted DSM, the disassembly property in maintenance, recycling and reuse of configurable product are optimized.
基金supported by the National Natural Science Foundation of China(50964010)
文摘Semisolid rheoforming （SSR） is a promising technology for the production of Mg wrought alloy in foundry settings. In order to realize SSR, it is necessary to characterize the grain structure evolution during slurry preparation. In this paper, slurry of AZ31 alloy was produced by a novel rheocast process known as self-inoculation method （SIM）. Interrupted quenching technology was applied to investigate the primary a-Mg evolution during continuous cooling and isothermal holding. Results indicate that the initial microstructure of slurry produced by SIM is a mixture of irregular grains, which becomes ideally globular when the slurry slowly cools to 620 ~C and isothermally held for at least 30 s. The local solute diffusion leads to dendritic fragmentation and forms separated particles. During prolonged holding, the particle surface gradually becomes smooth because of protuberance melting and groove advancement. Coarsening of a-Mg grains in isothermal holding was analyzed using Lifshitz-Slyozov-Wagner theory. Results suggest that coalescence is most likely the dominant coarsening mechanism in the early stage while Ostwald ripening tends to be the principal one later. The EDS results indicate that a longer holding time leads to AI solute element segregation at the grain boundaries, but Zn distribution within liquid matrix has no obvious change.
基金supported by the National Natural Science Foundation of China (NSFC, No. 51522203, 51772040)Fok Ying Tung Education Foundation (No. 151047)+2 种基金the Recruitment Program of Global Youth ExpertsXinghai Scholarship of Dalian University of Technologythe Fundamental Research Funds for the Central Universities (No. DUT18LAB19)
文摘Use of metallic Li anode raises serious concerns on the safety and operational performance of Li-S batteries due to uncontrolled hazard of Li dendrite formation, which is difficultly eliminated as long as the metallic Li exists in the cells. Pairing lithium sulfide (Li2S) cathode with currently available metallic Lifree high-capacity anodes offers an alternative solution to this challenge. However, the performance of Li2S cathode is primarily restricted by high activation barrier upon initial charge, low active mass utilization and sluggish redox kinetics. Herein, a MXene-induced multifunctional collaborative interface is proposed to afford superb activity towards redox solid-liquid/liquid-liquid phase transformation, strong chemisorption, high conductivity and fast ionic/charge transport in high Li2S loading cathode. Applying collaborative interface effectively reduces initial voltage barrier of Li2S activation and regulates the kinetic behavior of redox polysulfide conversion. Therefore, stable operation of additive-free Li2S cathode with high areal capacities at high Li2S loading up to 9 mg cm^-2 can be achieved with less sacrifice of high capacity and rate capability in Li-S batteries. Rechargeable metallic Li-free batteries are successfully constructed by pairing this high-performance Li2S cathode with high-capacity metal oxide anodes, which delivers superior energy density to current Li-ion batteries.
基金supported by the National High Technology Research and Development Program of China (863 Program) (No. 2007AA06Z209)the National Natural Science Foundation of China (No. 50974104,50774062 and 50474039)
文摘Sulfur deposition in the formation, induced by a reduction in the solubility of the sulfur in the gas phase, may significantly reduce the inflow performance of sour gas wells and some wells in sour gas reservoirs have even become completely plugged with deposited sulfur within several months. Accurate prediction and effective management of sulfur deposition are crucial to the economic viability of sour gas reservoirs. In this paper, a dynamic flow experiment was carried out to investigate formation damage resulting from sulfur deposition using an improved experimental method. The core sample was extracted from the producing interval of the LG2 well, LG gas field in the Sichuan Basin. The experimental temperature was 26 °C and the initial pressure was 19 MPa. The displacement pressure continuously decreased from 19 to 10 MPa, and the depletion process lasted 15 days. Then the core was removed and dried. The core mass and core permeability were measured before and after experiments. Experimental results indicated that the core mass increased from 48.372 g before experiment to 48.386 g afterwards, while the core permeability reduced from 0.726 to 0.608 md during the experiment. Then the core was analyzed with a scanning electron microscope (SEM) and energy-dispersive X-ray mapping. The deposition pattern and micro-distribution of elemental sulfur was observed and the deposited elemental sulfur distributed as a film around the pore surface.
基金Supported by the State Key Lab of Explosion Science and Technology of BIT Under Contract (No. KFJJ04-3)
文摘An analytical model on the normal perforation of reinforced concrete slabs is constructed. The effect of reinforcing bars is further hybridized in a general three-stage model consisting of initial cratering, tunnelling and shear plugging. Besides three dimensionless numbers, i. e., the impact function I, the geometry function of projectile N and the dimensionless thickness of concrete target X, which are employed to predict the ballistic performance of perforation of concrete slabs, the reinforcement ratio Ps of concrete and the tensile strength fs of reinforcing bars are considered as the other main factors influencing the perforation process. Simpler solutions of ballistic performances of normal perforation of reinforced concrete slabs are formulated. Theoretical predictions agree well with individual published experimental data.
基金financially supported by the National Natural Science Foundation of China (Nos.52173257 and 51872159)。
文摘The polymer-ceramic composite electrolyte is considered as one of promising electrolytes for solid-state battery.However,in previous research,ceramic particles are usually dispersed in polymer matrix and could not form continuous Li+conductive channels.The agglomeration of ceramic particles could also lead to low ionic conductivity and poor interfacial electrode/electrolyte contact.In this paper,self-supported porous Li_(6.4)La_(3) Zr_(1.4)Ta_(0.6)O_(12)(LLZTO) electrolyte is synthesized by gelcasting process,which possesses three-dimensional(3D) interconnected pore channels and relatively high strength.The 1,3-dioxolane(DOL) could penetrate into the porous LLZTO framework for its excellent fluidity.The subsequent in situ polymerization process by thermal treatment could completely fill the internal pores and improve the interfacial contact with electrode.The resulting 3D composite electrolyte with dual continuous Li+transport channels in ceramic and polymer components exhibits high ionic conductivity of 2.8 × 10^(-4) S·cm^(-1) at room temperature and low Li/electrolyte interfacial resistance of 94 Ω·cm^(2) at 40 ℃.The corresponding Li/Li symmetric cell delivers stable voltage profiles for over 600 h under 0.1 and 0.2 mA·cm^(-2).The solid-state Li/LiFePO_(4) battery shows superior rate and cycling performance under 0.1 C and 0.2 C.This work guides the preparation of composite electrolyte with dual continuous Li+conductive paths as well as high ceramic ratio and interface modification strategy for solid-state Li metal battery.
基金supported by the National Key R&D Program of China(No.2016FYE0112700)the National Natural Science Foundation of China(No.41671296)the Science and Technology Department of Zhejiang Province of China(No.2017C02016)
文摘Phyllostachys praecox is a bamboo species cultivated for edible shoots under intensive management.However,the potential pollution risk of heavy metals in bamboo soils is not clear under the intensive management for a long term.The objective of this study was to evaluate the effect of cultivation time on soil heavy metal accumulation and bioavailability in bamboo stands subjected to intensive management.Soil samples were collected from a chronosequence of bamboo stands which had been cultivated for 0,1,2,4,8,and 10 years in Lin’an,Zhejiang Province of China.Eight heavy metals(Cu,Zn,Pb,Ni,Cr,Cd,As,and Hg)present in the soil were selected,and their potential pollution risk was evaluated by chemical speciation analysis.Possible heavy metal sources were explored using multivariate and cluster analysis.Our results showed that Zn,Cu,Hg,and Cd contents in the soil increased with the cultivation time,while Ni,Cr,Pb,and As levels were similar among all stands.Furthermore,the bioavailabilities of all analyzed heavy metals increased with the cultivation time.Multivariate and cluster analysis showed that sources of Ni,Cr,Pb,and As were likely lithogenic in origin,whereas input of Zn,Cu,Hg,and Cd was mainly due to cultivation practices.Current bamboo management strategies raised the potential risks of heavy metal pollution in bamboo shoots in the long term.Soil acidification in P.praecox stands induced by intensive cultivation should be controlled since it stimulated and improved the bioavailability of heavy metals.Appropriate management strategies should thus be adopted to ensure safe and sustainable production of bamboo shoots.
基金Funded by the New Century Excellent Talent Plan from Ministry of Education,China (No.NCET-05-0660)Fok YingTung Education Foundation (No. 101049)
文摘A simple method was developed to prepare the uniform hematite hollow submicro-spheres with controllable structure and different diameter based on monodisperse poly（styrene-co-acrylic acid） [P（St-co-AA）] particles. The structure and formation mechanism of the hollow spheres were investigated in detail. The control mechanism of shell thickness was also discussed. The results indicated that the shell thickness and coarseness of the synthesized core-shell hematite hollow spheres could be tuned simply by the surface carboxyl content of the P（St-co-AA） particles. This method provided a new approach for the structure control in the preparation of hollow spheres. A Brunauer-Emmett-Teller （BET） test shows that the prepared hollow spheres have large surface areas which were decreased along with the increase of the diameter. The magnetic properties of the as-obtained hematite hollow spheres were investigated. The result showed that the coercivity and saturated magnetization were increased along with the increase of the shell thickness, and the remanent magnetization was increased along with the decrease of the diameter.
