Environmental catalysis has been considered one of the important research topics.Some technologies(e.g.,photocatalysis and electrocatalysis)have been intensively developed with the advance of synthetic technologies of...Environmental catalysis has been considered one of the important research topics.Some technologies(e.g.,photocatalysis and electrocatalysis)have been intensively developed with the advance of synthetic technologies of catalytical materials.In 2019,we discussed the development trend of this field,and wrote a roadmap on this topic in Chinese Chemical Letters(30(2019)2065-2088).Nowadays,we discuss it again from a new viewpoint along this road.In this paper,several subtopics are discussed,e.g.,photocatalysis based on titanium dioxide,violet phosphorus,graphitic carbon and covalent organic frameworks,electrocatalysts based on carbon,metal-and covalent-organic framework.Finally,we hope that this roadmap can enrich the development of two-dimensional materials in environmental catalysis with novel understanding,and give useful inspiration to explore new catalysts for practical applications.展开更多
The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an over...The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.展开更多
The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to...The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to its rich mineral and geothermal resources.This review provides a comprehensive analysis of As content,focusing on its distribution,environmental migration,and transformation behavior across the plateau.The review further evaluates the distribution of As in different functional areas,revealing that geothermal fields(107.2 mg/kg),mining areas(53.8 mg/kg),and croplands(39.3 mg/kg)have the highest As concentrations,followed by river and lake sediments and adjacent areas(33.1 mg/kg).These elevated levels are primarily attributed to the presence of As-rich minerals,such as arsenopyrite and pyrite.Additionally,human activities,including mining and geothermal energy production,exacerbate the release of As into the environment.The review also highlights the role of localmicroorganisms,particularly those fromthe phyla Proteobacteria and Actinobacteria,which possess As metabolic genes that facilitate As translocation.Given the unique climatic conditions of the plateau,conventionalmethods for As controlmay not be fully effective.However,the review identifies promising remediation strategies that are environmentally adaptable,such as the use of local microorganisms,specific adsorbents,and integrated technologies,which offer potential solutions for managing and utilizing Ascontaminated soils on the plateau.展开更多
Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investiga...Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.展开更多
To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions tha...To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.展开更多
Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoti...Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoting high-quality development of new energy in China.This paper constructs an evaluation index system for the development of NEVs and the ecological environment.It uses game theory combining weighting model,particle swarm optimized projection tracking evaluation model,coupling coordination degree model,and machine learning algorithms to calculate and analyze the level of coupling coordination development of NEVs and the ecological environment in China from 2010 to 2021,and identifies the driving factors.The research results show that:(i)From 2010 to 2021,the development index of NEVs in China has steadily increased from 0.085 to 0.634,while the ecological environment level index significantly rose from 0.170 to 0.884,reflecting the continuous development of China in both NEVs and the ecological environment.(ii)From 2010 to 2012,the two systems—new energy vehicle(NEV)development and the ecological environment—were in a period of imbalance and decline.From 2013 to 2016,they underwent a transition period,and from 2017 to 2021,they entered a period of coordinated development showing a trend of benign and continuous improvement.By 2021,they reached a good level of coordination.(iii)Indicators such as the number of patents granted for NEVs,water consumption per unit of GDP,and energy consumption per unit of GDP are the main driving factors affecting the coupling coordination development of NEVs and the ecological environment in China.展开更多
This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station...This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station planning and development.Data from 159 metro stations in Nanjing,collected over a 14-d period,were analyzed to identify changes in weekday and weekend ridership patterns.The analysis included explanatory variables grouped into three categories:urban spatial variables,socioeconomic vari-ables,and transit service variables.A geographically and temporally weighted regression(GTWR)model was developed,and its performance was compared with that of ordinary least squares(OLS)and geographically weighted regression(GWR)models.The results demonstrated that the GTWR model outperformed others in analyzing the relationship between rail transit ridership and the built environment.In addition,the coefficients of explanatory variables showed significant variation across spatiotemporal dimensions,revealing distinct patterns.Notably,the influence of commuter flows led to more pronounced temporal heterogeneity in the coefficients observed on weekdays.These findings offer valuable insights for optimizing urban public transportation systems and advancing integrated urban rail development.展开更多
A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface...A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.展开更多
With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an import...With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an important criterion for measuring the quality of business environment.This article is intended to explore the current status of intellectual property system construction in China,the challenges,and its relationship with the business environment,to propose the corresponding countermeasures and suggestions.The study finds that the legal system of intellectual property in China is gradually improving,and judicial and administrative protection are continuously strengthened.However,the challenges still remain such as frequent infringements,rights hard to protect and insufficient international cooperation.These issues not only affect the legitimate rights and interests of innovation entities,but also for the market fairness and the level of the business environment.Therefore,this article proposes that strengthening the perfection of the intellectual property legal system,enhancing intellectual property services and support capabilities,strengthening international cooperation and exchanges,and accelerating the cultivation of composite talents.It aims to provide theoretical references for the construction of intellectual property system and the optimization of the business environment,promote the high-quality development of economy and enhance the global competitiveness of the country.展开更多
This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is ...This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.展开更多
Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the...Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the reinforcement reliable,this experiment mixed(ultrafine cement)UFC into ordinary cement to form a composite solidify agent.This study aimed to analyze the influence of UFC proportion on the strength of cement-soil in the peat soil environment.Unconfined compressive strength(UCS)and scanning electron microscope(SEM)tests were conducted on samples soaked for 28 and 90 days,respectively.The test results show that without considering the effects of Humic Acid(HA)and Fulvic Acid(FA),incorporating UFC can significantly improve the UCS of cement-soil.The rapid hydration of the fine particles generates a large number of cementitious products,improves the cohesion of the soil skeleton,and fills the pores.However,when the proportion of UFC increases,the aggregate structure formed by a larger quantity of fine particles reduces the hydration rate and degree of cement hydration,making the UCS growth rate of cement-soil insignificant.In the peat soil environment,HA significantly weakened the UCS of cement-soil in both physical and chemical aspects.However,UFC can mitigate the adverse effect of HA on cement-soil by its small particle size,high surface energy,and solid binding ability.In addition,FA has a positive effect on the UCS of cement-soil soaked for 28 days and 90 days.The UFC addition could promote the enhancement effect of FA on cement-soil UCS.SEM test results showed that cement hydration products increased significantly with the increase of UFC proportion,and cementation between hydration products and soil particles was enhanced.The size and connectivity of cement-soil pores were significantly reduced,thereby improving cement-soil structural integrity.展开更多
Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework n...Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.展开更多
Lithium-sulfur(Li-S)batteries with high energy density and capacity have garnered significant research attention among various energy storage devices.However,the shuttle effect of polysulfides(LiPSs)remains a major ch...Lithium-sulfur(Li-S)batteries with high energy density and capacity have garnered significant research attention among various energy storage devices.However,the shuttle effect of polysulfides(LiPSs)remains a major challenge for their practical application.The design of battery separators has become a key aspect in addressing the challenge.MXenes,a promising two-dimensional(2D)material,offer exceptional conductivity,large surface area,high mechanical strength,and active sites for surface reactions.When assembled into layered films,MXenes form highly tunable two-dimensional channels ranging from a few angstroms to over 1 nm.These nanoconfined channels are instrumental in facilitating lithium-ion transport while effectively impeding the shuttle effect of LiPSs,which are essential for improving the specific capacity and cyclic stability of Li-S batteries.Substantial progress has been made in developing MXenes-based separators for Li-S batteries,yet there remains a research gap in summarizing advancements from the perspective of interlayer engineering.This entails maintaining the 2D nanochannels of layered MXenes-based separators while modulating the physicochemical environment within the MXenes interlayers through targeted modifications.This review highlights advancements in in situ modification of MXenes and their integration with 0D,1D,and 2D materials to construct laminated nanocomposite separators for Li-S batteries.The future development directions of MXenes-based materials in Li-S energy storage devices are also outlined,to drive further advancements in MXenes for Li-S battery separators.展开更多
The neighborhood is where China survives and thrives as well as the foundation of its development and prosperity.Chinese President Xi Jinping stressed during the Central Conference on Work Relating to Neighborhood Dip...The neighborhood is where China survives and thrives as well as the foundation of its development and prosperity.Chinese President Xi Jinping stressed during the Central Conference on Work Relating to Neighborhood Diplomacy convened in October 2013 that“China’s neighborhood is of critical strategic significance in terms of geographical location,natural environment as well as mutual relations.”展开更多
The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, ...The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, including 10 radiologists working in the hospitals covered by the survey, to assess the practice of pediatric radiology and the degree of compliance with radiation protection principles for the safety of children and the environment. We collected radiophysical parameters to calculate entrance doses in pediatric radiology in radiology departments to determine the dosimetric level by comparison with the diagnostic reference levels of the International Commission on Radiological Protection (ICRP). All in all, we found that in Kongo Central in the DRC, many health personnel surveyed reported that more than 30% of requested radiological examinations are not justified. Also, after comparing the entrance doses produced in the surveyed departments with those of the International Commission on Radiological Protection (ICRP), a statistically significant difference was found in pediatric radiology between the average doses in five out of six surveyed departments and those of the ICRP. Therefore, almost all of the surveyed departments were found to be highly irradiating in children, while excessive X-ray irradiation in children can have significant effects due to their increased sensitivity to radiation. Among the risks are: increased cancer risks, damage to developing cells, potential genetic effects, and neurological effects. This is why support for implementing radiation protection principles is a necessity to promote the safety of patients and the environment against the harmful effects of X-rays in conventional radiology.展开更多
Titanium dioxide(TiO_(2))has been an important protective ingredient in mineral-based sunscreens since the 1990s.However,traditional TiO_(2)nanoparticle formulations have seen little improvement over the past decades ...Titanium dioxide(TiO_(2))has been an important protective ingredient in mineral-based sunscreens since the 1990s.However,traditional TiO_(2)nanoparticle formulations have seen little improvement over the past decades and continue to face persistent challenges related to light transmission,biosafety,and visual appearance.Here,we report the discovery of two-dimensional(2D)TiO_(2),characterized by a micro-sized lateral dimension(~1.6μm)and atomic-scale thickness,which fundamentally resolves these long-standing issues.The 2D structure enables exceptional light management,achieving 80%visible light transparency—rendering it nearly invisible on the skin—while maintaining UV-blocking performance comparable to unmodified rutile TiO_(2)nanoparticles.Its larger lateral size results in a two-orders-of-magnitude reduction in skin penetration(0.96 w/w%),significantly enhancing biosafety.Moreover,the unique layered architecture inherently suppresses the generation of reactive oxygen species(ROS)under sunlight exposure,reducing the ROS generation rate by 50-fold compared to traditional TiO_(2)nanoparticles.Through precise metal element modulation,we further developed the first customizable sunscreen material capable of tuning UV protection ranges and automatically matching diverse skin tones.The 2D TiO_(2)offers a potentially transformative approach to modern sunscreen formulation,combining superior UV protection,enhanced safety and a natural appearance.展开更多
Focusing on investment security along the Belt and Road(B&R)routes,this study analyzes the geopolitical environment(GE)of countries(regions)along the B&R routes from two dimensions:political and business envir...Focusing on investment security along the Belt and Road(B&R)routes,this study analyzes the geopolitical environment(GE)of countries(regions)along the B&R routes from two dimensions:political and business environment(PBE)and political orientation.The results show that since the proposal of the B&R Initiative in 2013,the PBE of these countries(regions)has shown slight improvement but with significant spatial disparities,presenting a pattern of better conditions in the eastern and western regions and poorer conditions in the central regions.There is no strong spatial dependence in the PBE among these countries(regions),but a weak homogenization trend toward improvement is observed.Low-scoring countries(regions)are mainly located in former Commonwealth of Independent States(CIS),the Middle East,and the Indochina Peninsula.These countries(regions)exhibit weak interconnections,demonstrating a characteristic of“similarity without harmony.”(a Confucian concept describing nations sharing superficial traits but lacking substantive cooperation).Therefore,the B&R construction should adopt a clustered and contiguous breakthrough strategy.The evaluation of political orientation reveals significant political divergence among B&R countries(regions),with varying attitudes toward China.Moreover,as pro-China sentiment increases,the PBE tends to deteriorate.This negative correlation suggests that countries(regions)actively engaging in the B&R Initiative generally face political instability and economic underdevelopment,and seek to leverage the B&R Initiative for domestic growth.Consequently,while prioritizing investment security,it is important for the B&R construction to actively promote Chinese values in order to garner support and participation from countries(regions)with more favorable PBE.Given the generally underdeveloped PBE and political polarization among B&R countries(regions),China urgently needs to develop a geopolitical theory aligned with the B&R's geopolitical model to safeguard its advancement.Simultaneously,China should reshape geopolitical narratives to reclaim discourse power in political interpretation.This study provides preliminary insights into cross-country(regional)political polarization and contributes to advancing GE research.展开更多
Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in ...Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in preterm infants.The aspects and extent to which the home environment affects the early(18 months corrected age)neuropsychological development of preterm infants are still unclear.Aims This study aimed to analyse the effect of the home environment on the neuropsychiatric development of preterm infants at 18 months corrected age after discharge from the neonatal intensive care unit(NICU).It also sought to provide a basis for promoting neuropsychiatric development among preterm infants by improving the home environment.Methods In this retrospective cross-sectional study,275 preterm infants born between January 2019 and January 2022 were followed up for systematic management after discharge from the NICU at Shanghai Children's Hospital.The Home Nurture Environment Questionnaire was used to assess the home environment of the infants and analyse its impact on the developmental quotient(evaluated by the Gesell Developmental Scale)and the rate of developmental delays at 18 months corrected age.Results A total of 41.454%of the infants were extremely preterm.The developmental quotient scores at 18 months corrected age were in the middle of the scale.The language domain had the highest rate of developmental delay(46.182%),followed by the adaptive domain(37.091%).Multiple logistic regression analyses showed that compared with infants in supportive home environments,infants with moderate/unsupportive home environments had significantly elevated risks of development delay:2.162-fold for global(odds ratio(OR)2.162,95% confidence interval(Cl)1.274 to 3.665,p=0.004),2.193-fold for fine motor(OR 2.193,95%CI 1.161 to 4.140,p=0.016),2.249-fold for language(0R 2.249,95%CI 1.336 to 3.786,p=0.002)and 2.042-fold for personal-social(OR 2.042,95%CI 1.149 to 3.628,p=0.015).Conclusions A supportive home environment is a crucial protective factor for the neuropsychological development of preterm infants.It is associated with higher developmental quotient scores and protects against neuropsychiatric delays.Incorporating evaluation and continuous improvement of the home environment into the management framework for preterm infants to promote optimal neurodevelopment is essential.展开更多
Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high ef...Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high efficiency and reliability.However,the ambiguity surrounding the output flow characteristics of individual two-dimensional pumps poses a significant challenge in achieving precise closed-loop control of the EHA positions.To address this issue,this study established a comprehensive numerical model that included gap leakage to analyze the impact of leakage on the output flow characteristics of a two-dimensional piston pump.The validity of the numerical analysis was indirectly confirmed through meticulous measurements of the leakage and volumetric efficiency,ensuring robust results.The research findings indicated that,at lower pump speeds,leakage significantly affected the output flow rate,leading to potential inefficiencies in the system.Conversely,at higher rotational speeds,the impact of leakage was less pronounced,implying that the influence of leakage on the pump outlet flow must be carefully considered and managed for EHAs to perform position servo control.Additionally,the research demonstrates that two-dimensional motion does not have a unique or additional effect on pump leakage,thus simplifying the design considerations.Finally,the study concluded that maintaining an oil-filled leakage environment is beneficial because it helps reduce the impact of leakage and enhances the overall volumetric efficiency of the pump system.展开更多
It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament ch...It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament chemical vapor deposition setup,followed by annealing treatment under different temperatures at ambient pressure.The results indicate that when the annealing temperature increases from 700℃ to 1000℃,the size of the 2D-diamond found in the samples gradually increases from close to 20 nm to around 30 nm.Meanwhile,the size and number of amorphous carbon spheres and Ta-containing compounds between the graphene layers gradually increase.As the annealing temperature continues to rise to 1100℃,a significant aggregation of Ta-containing compounds is observed in the samples,with no diamond structure detected.This further confirms that monodisperse Ta atoms play a key role in graphene phase transition into 2D-diamond.This study provides a novel method for the ambient-pressure phase transition of graphene into 2D-diamond.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52272290,21972030,52073119,and 52373210)the Natural Science Foundation of Jilin Province(No.20230101029JC)+1 种基金the Fundamental Research Program of Shanxi Province(No.202303021212159)the Monash University Malaysia–ASEAN grant(No.ASE-000010)。
文摘Environmental catalysis has been considered one of the important research topics.Some technologies(e.g.,photocatalysis and electrocatalysis)have been intensively developed with the advance of synthetic technologies of catalytical materials.In 2019,we discussed the development trend of this field,and wrote a roadmap on this topic in Chinese Chemical Letters(30(2019)2065-2088).Nowadays,we discuss it again from a new viewpoint along this road.In this paper,several subtopics are discussed,e.g.,photocatalysis based on titanium dioxide,violet phosphorus,graphitic carbon and covalent organic frameworks,electrocatalysts based on carbon,metal-and covalent-organic framework.Finally,we hope that this roadmap can enrich the development of two-dimensional materials in environmental catalysis with novel understanding,and give useful inspiration to explore new catalysts for practical applications.
基金the support from the National Natural Science Foundation of China(22272004,62272041)the Fundamental Research Funds for the Central Universities(YWF-22-L-1256)+1 种基金the National Key R&D Program of China(2023YFC3402600)the Beijing Institute of Technology Research Fund Program for Young Scholars(No.1870011182126)。
文摘The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.
基金supported by the Central Public-interest Scientific Institution Basal Research Fund(No.Y2024QC29)the Central Public-interest Scientific Institution Basal Research Fund(Nos.2024-jbkyywf-lwj and 2024-jbkyywf-zyj).
文摘The Qinghai-Tibet Plateau,with its high altitude and cold climate,is one of the most fragile ecological environments in China and is distinguished by its naturally elevated arsenic(As)levels in the soil,largely due to its rich mineral and geothermal resources.This review provides a comprehensive analysis of As content,focusing on its distribution,environmental migration,and transformation behavior across the plateau.The review further evaluates the distribution of As in different functional areas,revealing that geothermal fields(107.2 mg/kg),mining areas(53.8 mg/kg),and croplands(39.3 mg/kg)have the highest As concentrations,followed by river and lake sediments and adjacent areas(33.1 mg/kg).These elevated levels are primarily attributed to the presence of As-rich minerals,such as arsenopyrite and pyrite.Additionally,human activities,including mining and geothermal energy production,exacerbate the release of As into the environment.The review also highlights the role of localmicroorganisms,particularly those fromthe phyla Proteobacteria and Actinobacteria,which possess As metabolic genes that facilitate As translocation.Given the unique climatic conditions of the plateau,conventionalmethods for As controlmay not be fully effective.However,the review identifies promising remediation strategies that are environmentally adaptable,such as the use of local microorganisms,specific adsorbents,and integrated technologies,which offer potential solutions for managing and utilizing Ascontaminated soils on the plateau.
基金supported by the Fundamental Research Funds of the Institute of Geomechanics(DZLXJK202401)the National Natural Science Foundation of China(42177172,U2244226,42172255)+1 种基金the China Geological Survey Project(DD20230538)Deep Earth Probe and Mineral Resources ExplorationNational Science and Technology Major Project(2024ZD1000500)。
文摘Knowledge of the seismogenic environment of fault zones is critical for understanding the processes and mechanisms of large earthquakes.We conducted a rock magnetic study of the fault rocks and protoliths to investigate the seismogenic environment of earthquakes in the Motuo fault zone,in the eastern Himalayan syntaxis.The results indicate that magnetite is the principal magnetic carrier in the fault rocks and protolith,while the protolith has a higher content of paramagnetic minerals than the fault rocks.The fault rocks are characterized by a high magnetic susceptibility relative to the protolith in the Motuo fault zone.This is likely due to the thermal alteration of paramagnetic minerals to magnetite caused by coseismic frictional heating with concomitant hydrothermal fluid circulation.The high magnetic susceptibility of the fault rocks and neoformed magnetite indicate that large earthquakes with frictional heating temperatures>500℃have occurred in the Motuo fault zone in the past,and that the fault maintained an oxidizing environment with weak fluid action during these earthquakes.Our results reveal the seismogenic environment of the Motuo fault zone,and they are potentially important for the evaluation of the regional stability in the eastern Himalayan syntaxis.
基金supported by the Beijing Natural Science Foundation(No.L212029)the National Natural Science Foundation of China(No.62271043).
文摘To meet the requirements of electromagnetic(EM)theory and applied physics,this study presents an overview of the state-of-the-art research on obtaining the EM properties of media and points out potential solutions that can break through the bottlenecks of current methods.Firstly,based on the survey of three mainstream approaches for acquiring EM properties of media,we identify the difficulties when implementing them in realistic environments.With a focus on addressing these problems and challenges,we propose a novel paradigm for obtaining the EM properties of multi-type media in realistic environments.Particularly,within this paradigm,we describe the implementation approach of the key technology,namely“multipath extraction using heterogeneous wave propagation data in multi-spectrum cases”.Finally,the latest measurement and simulation results show that the EM properties of multi-type media in realistic environments can be precisely and efficiently acquired by the methodology proposed in this study.
基金Supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0102)the China Scholarship Council Program(202406190114)。
文摘Studying the coupling coordination development of new energy vehicles(NEVs)and the ecological environment in China is helpful in promoting the development of NEVs in the country and is of great significance in promoting high-quality development of new energy in China.This paper constructs an evaluation index system for the development of NEVs and the ecological environment.It uses game theory combining weighting model,particle swarm optimized projection tracking evaluation model,coupling coordination degree model,and machine learning algorithms to calculate and analyze the level of coupling coordination development of NEVs and the ecological environment in China from 2010 to 2021,and identifies the driving factors.The research results show that:(i)From 2010 to 2021,the development index of NEVs in China has steadily increased from 0.085 to 0.634,while the ecological environment level index significantly rose from 0.170 to 0.884,reflecting the continuous development of China in both NEVs and the ecological environment.(ii)From 2010 to 2012,the two systems—new energy vehicle(NEV)development and the ecological environment—were in a period of imbalance and decline.From 2013 to 2016,they underwent a transition period,and from 2017 to 2021,they entered a period of coordinated development showing a trend of benign and continuous improvement.By 2021,they reached a good level of coordination.(iii)Indicators such as the number of patents granted for NEVs,water consumption per unit of GDP,and energy consumption per unit of GDP are the main driving factors affecting the coupling coordination development of NEVs and the ecological environment in China.
基金The National Key Research and Development Program of China(No.2022YFC3800201).
文摘This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station planning and development.Data from 159 metro stations in Nanjing,collected over a 14-d period,were analyzed to identify changes in weekday and weekend ridership patterns.The analysis included explanatory variables grouped into three categories:urban spatial variables,socioeconomic vari-ables,and transit service variables.A geographically and temporally weighted regression(GTWR)model was developed,and its performance was compared with that of ordinary least squares(OLS)and geographically weighted regression(GWR)models.The results demonstrated that the GTWR model outperformed others in analyzing the relationship between rail transit ridership and the built environment.In addition,the coefficients of explanatory variables showed significant variation across spatiotemporal dimensions,revealing distinct patterns.Notably,the influence of commuter flows led to more pronounced temporal heterogeneity in the coefficients observed on weekdays.These findings offer valuable insights for optimizing urban public transportation systems and advancing integrated urban rail development.
文摘A functional interlayer based on two-dimensional(2D)porous modified vermiculite nanosheets(PVS)was obtained by acid-etching vermiculite nanosheets.The as-obtained 2D porous nanosheets exhibited a high specific surface area of 427 m^(2)·g^(-1)and rich surface active sites,which help restrain polysulfides(LiPSs)through good physi-cal and chemical adsorption,while simultaneously accelerating the nucleation and dissolution kinetics of Li_(2)S,effec-tively suppressing the shuttle effect.The assembled lithium-sulfur batteries(LSBs)employing the PVS-based inter-layer delivered a high initial discharge capacity of 1386 mAh·g^(-1)at 0.1C(167.5 mAh·g^(-1)),long-term cycling stabil-ity,and good rate property.
基金Guizhou Provincial University Humanities and Social Sciences Research Project in 2024"Enhancing the Development of New Productive Forces through University Technological Innovation and Intellectual Property Management"(2024RW256)Guizhou University of Commerce Research Project in 2022"Study on the Ideas and Pathways to Drive Agricultural Powerhouse through Digital Economy"(2022XJZX315)。
文摘With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an important criterion for measuring the quality of business environment.This article is intended to explore the current status of intellectual property system construction in China,the challenges,and its relationship with the business environment,to propose the corresponding countermeasures and suggestions.The study finds that the legal system of intellectual property in China is gradually improving,and judicial and administrative protection are continuously strengthened.However,the challenges still remain such as frequent infringements,rights hard to protect and insufficient international cooperation.These issues not only affect the legitimate rights and interests of innovation entities,but also for the market fairness and the level of the business environment.Therefore,this article proposes that strengthening the perfection of the intellectual property legal system,enhancing intellectual property services and support capabilities,strengthening international cooperation and exchanges,and accelerating the cultivation of composite talents.It aims to provide theoretical references for the construction of intellectual property system and the optimization of the business environment,promote the high-quality development of economy and enhance the global competitiveness of the country.
文摘This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.
基金National Natural Science Foundation of China(No.41967035)。
文摘Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the reinforcement reliable,this experiment mixed(ultrafine cement)UFC into ordinary cement to form a composite solidify agent.This study aimed to analyze the influence of UFC proportion on the strength of cement-soil in the peat soil environment.Unconfined compressive strength(UCS)and scanning electron microscope(SEM)tests were conducted on samples soaked for 28 and 90 days,respectively.The test results show that without considering the effects of Humic Acid(HA)and Fulvic Acid(FA),incorporating UFC can significantly improve the UCS of cement-soil.The rapid hydration of the fine particles generates a large number of cementitious products,improves the cohesion of the soil skeleton,and fills the pores.However,when the proportion of UFC increases,the aggregate structure formed by a larger quantity of fine particles reduces the hydration rate and degree of cement hydration,making the UCS growth rate of cement-soil insignificant.In the peat soil environment,HA significantly weakened the UCS of cement-soil in both physical and chemical aspects.However,UFC can mitigate the adverse effect of HA on cement-soil by its small particle size,high surface energy,and solid binding ability.In addition,FA has a positive effect on the UCS of cement-soil soaked for 28 days and 90 days.The UFC addition could promote the enhancement effect of FA on cement-soil UCS.SEM test results showed that cement hydration products increased significantly with the increase of UFC proportion,and cementation between hydration products and soil particles was enhanced.The size and connectivity of cement-soil pores were significantly reduced,thereby improving cement-soil structural integrity.
基金supported in part by the National Natural Science Foundations of China(Nos.61175084,61673042 and 62203046)the China Postdoctoral Science Foundation(No.2022M713006).
文摘Aiming to address the Unmanned Aerial Vehicle(UAV) formation collision avoidance problem in Three-Dimensional(3-D) low-altitude environments where dense various obstacles exist, a fluid-based path planning framework named the Formation Interfered Fluid Dynamical System(FIFDS) with Moderate Evasive Maneuver Strategy(MEMS) is proposed in this study.First, the UAV formation collision avoidance problem including quantifiable performance indexes is formulated. Second, inspired by the phenomenon of fluids continuously flowing while bypassing objects, the FIFDS for multiple UAVs is presented, which contains a Parallel Streamline Tracking(PST) method for formation keeping and the traditional IFDS for collision avoidance. Third, to rationally balance flight safety and collision avoidance cost, MEMS is proposed to generate moderate evasive maneuvers that match up with collision risks. Comprehensively containing the time and distance safety information, the 3-D dynamic collision regions are modeled for collision prediction. Then, the moderate evasive maneuver principle is refined, which provides criterions of the maneuver amplitude and direction. On this basis, an analytical parameter mapping mechanism is designed to online optimize IFDS parameters. Finally, the performance of the proposed method is validated by comparative simulation results and real flight experiments using fixed-wing UAVs.
基金supported by Beijing Natural Science Foundation(Nos.2232037 and 2242035)the National Natural Science Foundation of China(Nos.22005012,22105012 and 51803183)+1 种基金Chunhui Plan Cooperative Project of Ministry of Education(No.202201298)the China Postdoctoral Science Foundation Funded Project(No.2023M733520).
文摘Lithium-sulfur(Li-S)batteries with high energy density and capacity have garnered significant research attention among various energy storage devices.However,the shuttle effect of polysulfides(LiPSs)remains a major challenge for their practical application.The design of battery separators has become a key aspect in addressing the challenge.MXenes,a promising two-dimensional(2D)material,offer exceptional conductivity,large surface area,high mechanical strength,and active sites for surface reactions.When assembled into layered films,MXenes form highly tunable two-dimensional channels ranging from a few angstroms to over 1 nm.These nanoconfined channels are instrumental in facilitating lithium-ion transport while effectively impeding the shuttle effect of LiPSs,which are essential for improving the specific capacity and cyclic stability of Li-S batteries.Substantial progress has been made in developing MXenes-based separators for Li-S batteries,yet there remains a research gap in summarizing advancements from the perspective of interlayer engineering.This entails maintaining the 2D nanochannels of layered MXenes-based separators while modulating the physicochemical environment within the MXenes interlayers through targeted modifications.This review highlights advancements in in situ modification of MXenes and their integration with 0D,1D,and 2D materials to construct laminated nanocomposite separators for Li-S batteries.The future development directions of MXenes-based materials in Li-S energy storage devices are also outlined,to drive further advancements in MXenes for Li-S battery separators.
文摘The neighborhood is where China survives and thrives as well as the foundation of its development and prosperity.Chinese President Xi Jinping stressed during the Central Conference on Work Relating to Neighborhood Diplomacy convened in October 2013 that“China’s neighborhood is of critical strategic significance in terms of geographical location,natural environment as well as mutual relations.”
文摘The purpose of this research was to evaluate radiological safety in pediatric radiology in hospitals in the Kongo Central province of the DRC. To this end, we surveyed a convenience sample of 50 health professionals, including 10 radiologists working in the hospitals covered by the survey, to assess the practice of pediatric radiology and the degree of compliance with radiation protection principles for the safety of children and the environment. We collected radiophysical parameters to calculate entrance doses in pediatric radiology in radiology departments to determine the dosimetric level by comparison with the diagnostic reference levels of the International Commission on Radiological Protection (ICRP). All in all, we found that in Kongo Central in the DRC, many health personnel surveyed reported that more than 30% of requested radiological examinations are not justified. Also, after comparing the entrance doses produced in the surveyed departments with those of the International Commission on Radiological Protection (ICRP), a statistically significant difference was found in pediatric radiology between the average doses in five out of six surveyed departments and those of the ICRP. Therefore, almost all of the surveyed departments were found to be highly irradiating in children, while excessive X-ray irradiation in children can have significant effects due to their increased sensitivity to radiation. Among the risks are: increased cancer risks, damage to developing cells, potential genetic effects, and neurological effects. This is why support for implementing radiation protection principles is a necessity to promote the safety of patients and the environment against the harmful effects of X-rays in conventional radiology.
基金supported by the National Key Research and Development Project(No.2019YFA0705403)the National Natural Science Foundation of China(No.T2293693,52273311)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2020B0301030002)and the Shenzhen Basic Research Project(Nos.WDZC20200824091903001,JSGG20220831105402004,JCYJ20220818100806014)Shenzhen Major Science and Technology Projects(Nos.KCXFZ20240903094013018,KCXFZ20240903094203005)。
文摘Titanium dioxide(TiO_(2))has been an important protective ingredient in mineral-based sunscreens since the 1990s.However,traditional TiO_(2)nanoparticle formulations have seen little improvement over the past decades and continue to face persistent challenges related to light transmission,biosafety,and visual appearance.Here,we report the discovery of two-dimensional(2D)TiO_(2),characterized by a micro-sized lateral dimension(~1.6μm)and atomic-scale thickness,which fundamentally resolves these long-standing issues.The 2D structure enables exceptional light management,achieving 80%visible light transparency—rendering it nearly invisible on the skin—while maintaining UV-blocking performance comparable to unmodified rutile TiO_(2)nanoparticles.Its larger lateral size results in a two-orders-of-magnitude reduction in skin penetration(0.96 w/w%),significantly enhancing biosafety.Moreover,the unique layered architecture inherently suppresses the generation of reactive oxygen species(ROS)under sunlight exposure,reducing the ROS generation rate by 50-fold compared to traditional TiO_(2)nanoparticles.Through precise metal element modulation,we further developed the first customizable sunscreen material capable of tuning UV protection ranges and automatically matching diverse skin tones.The 2D TiO_(2)offers a potentially transformative approach to modern sunscreen formulation,combining superior UV protection,enhanced safety and a natural appearance.
基金CAS-ANSO Sustainable Development Research Project,No.CAS-ANSO-SDRP-2024-08National Natural Science Foundation of China,No.42071153,No.41101119。
文摘Focusing on investment security along the Belt and Road(B&R)routes,this study analyzes the geopolitical environment(GE)of countries(regions)along the B&R routes from two dimensions:political and business environment(PBE)and political orientation.The results show that since the proposal of the B&R Initiative in 2013,the PBE of these countries(regions)has shown slight improvement but with significant spatial disparities,presenting a pattern of better conditions in the eastern and western regions and poorer conditions in the central regions.There is no strong spatial dependence in the PBE among these countries(regions),but a weak homogenization trend toward improvement is observed.Low-scoring countries(regions)are mainly located in former Commonwealth of Independent States(CIS),the Middle East,and the Indochina Peninsula.These countries(regions)exhibit weak interconnections,demonstrating a characteristic of“similarity without harmony.”(a Confucian concept describing nations sharing superficial traits but lacking substantive cooperation).Therefore,the B&R construction should adopt a clustered and contiguous breakthrough strategy.The evaluation of political orientation reveals significant political divergence among B&R countries(regions),with varying attitudes toward China.Moreover,as pro-China sentiment increases,the PBE tends to deteriorate.This negative correlation suggests that countries(regions)actively engaging in the B&R Initiative generally face political instability and economic underdevelopment,and seek to leverage the B&R Initiative for domestic growth.Consequently,while prioritizing investment security,it is important for the B&R construction to actively promote Chinese values in order to garner support and participation from countries(regions)with more favorable PBE.Given the generally underdeveloped PBE and political polarization among B&R countries(regions),China urgently needs to develop a geopolitical theory aligned with the B&R's geopolitical model to safeguard its advancement.Simultaneously,China should reshape geopolitical narratives to reclaim discourse power in political interpretation.This study provides preliminary insights into cross-country(regional)political polarization and contributes to advancing GE research.
基金funded by Shanghai Municipal Health and Wellness Commission Health Industry Clinical Research Special Project(202140299).
文摘Background There have been numerous intervention studies focusing on the development of preterm infants,but there has been limited investigation into the home environment as a determinant of developmental outcomes in preterm infants.The aspects and extent to which the home environment affects the early(18 months corrected age)neuropsychological development of preterm infants are still unclear.Aims This study aimed to analyse the effect of the home environment on the neuropsychiatric development of preterm infants at 18 months corrected age after discharge from the neonatal intensive care unit(NICU).It also sought to provide a basis for promoting neuropsychiatric development among preterm infants by improving the home environment.Methods In this retrospective cross-sectional study,275 preterm infants born between January 2019 and January 2022 were followed up for systematic management after discharge from the NICU at Shanghai Children's Hospital.The Home Nurture Environment Questionnaire was used to assess the home environment of the infants and analyse its impact on the developmental quotient(evaluated by the Gesell Developmental Scale)and the rate of developmental delays at 18 months corrected age.Results A total of 41.454%of the infants were extremely preterm.The developmental quotient scores at 18 months corrected age were in the middle of the scale.The language domain had the highest rate of developmental delay(46.182%),followed by the adaptive domain(37.091%).Multiple logistic regression analyses showed that compared with infants in supportive home environments,infants with moderate/unsupportive home environments had significantly elevated risks of development delay:2.162-fold for global(odds ratio(OR)2.162,95% confidence interval(Cl)1.274 to 3.665,p=0.004),2.193-fold for fine motor(OR 2.193,95%CI 1.161 to 4.140,p=0.016),2.249-fold for language(0R 2.249,95%CI 1.336 to 3.786,p=0.002)and 2.042-fold for personal-social(OR 2.042,95%CI 1.149 to 3.628,p=0.015).Conclusions A supportive home environment is a crucial protective factor for the neuropsychological development of preterm infants.It is associated with higher developmental quotient scores and protects against neuropsychiatric delays.Incorporating evaluation and continuous improvement of the home environment into the management framework for preterm infants to promote optimal neurodevelopment is essential.
基金Supported by National Natural Science Foundation of China(Grant No.52205072).
文摘Owing to their rolling friction,two-dimensional piston pumps are highly suitable as power components for electro-hydrostatic actuators(EHAs).These pumps are particularly advantageous for applications requiring high efficiency and reliability.However,the ambiguity surrounding the output flow characteristics of individual two-dimensional pumps poses a significant challenge in achieving precise closed-loop control of the EHA positions.To address this issue,this study established a comprehensive numerical model that included gap leakage to analyze the impact of leakage on the output flow characteristics of a two-dimensional piston pump.The validity of the numerical analysis was indirectly confirmed through meticulous measurements of the leakage and volumetric efficiency,ensuring robust results.The research findings indicated that,at lower pump speeds,leakage significantly affected the output flow rate,leading to potential inefficiencies in the system.Conversely,at higher rotational speeds,the impact of leakage was less pronounced,implying that the influence of leakage on the pump outlet flow must be carefully considered and managed for EHAs to perform position servo control.Additionally,the research demonstrates that two-dimensional motion does not have a unique or additional effect on pump leakage,thus simplifying the design considerations.Finally,the study concluded that maintaining an oil-filled leakage environment is beneficial because it helps reduce the impact of leakage and enhances the overall volumetric efficiency of the pump system.
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.U1809210)the International Science Technology Cooperation Program of China(Grant No.2014DFR51160)+3 种基金the One Belt and One Road International Cooperation Project from the Key Research and Development Program of Zhejiang Province,China(Grant No.2018C04021)the National Natural Science Foundation of China(Grant Nos.50972129,50602039,and 52102052)the Fund from Institute of Wenzhou,Zhejiang University(Grant Nos.XMGL-CX-202305 and XMGLKJZX-202307)the Project from Tanghe Scientific&Technology Company(Grant No.KYY-HX-20230024).
文摘It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament chemical vapor deposition setup,followed by annealing treatment under different temperatures at ambient pressure.The results indicate that when the annealing temperature increases from 700℃ to 1000℃,the size of the 2D-diamond found in the samples gradually increases from close to 20 nm to around 30 nm.Meanwhile,the size and number of amorphous carbon spheres and Ta-containing compounds between the graphene layers gradually increase.As the annealing temperature continues to rise to 1100℃,a significant aggregation of Ta-containing compounds is observed in the samples,with no diamond structure detected.This further confirms that monodisperse Ta atoms play a key role in graphene phase transition into 2D-diamond.This study provides a novel method for the ambient-pressure phase transition of graphene into 2D-diamond.
