Metallurgical slag is a waste or by-product of the metallurgical process,and its improper disposal can pose negative environmental impacts,including groundwater and soil contamination.The composition and properties of...Metallurgical slag is a waste or by-product of the metallurgical process,and its improper disposal can pose negative environmental impacts,including groundwater and soil contamination.The composition and properties of metallurgical slag are complex,which is usually difficult to use or process directly and requires special treatment and utilization methods.Taking converter slag and blast furnace slag as examples,the research frontiers and development potential were primarily discussed and analyzed in three aspects:the recycling within and outside metallurgical slag plants,the extraction and utilization of thermal energy from metallurgical slag,and the functionalization and social application of metallurgical slag.The metallurgical slag waste heat recovery includes chemical methods and physical methods.Among them,the physical method currently most used was centrifugal granulation to recover heat.Chemical laws could recover hydrogen through the waste heat of metallurgical slag,which could save fuel and reduce CO_(2) generated by fuel combustion.Metallurgical slag is rich in alkaline metal oxides,which can undergo a carbonation reaction with CO_(2) to achieve carbon sequestration in metallurgical slag.Elements such as iron,phosphorus,and silicon contained in metallurgical slag could be used in soil conditioners,cement raw materials,and wastewater treatment.For example,the phosphorus element in the slag could be extracted by melt modification followed by acid leaching and used as a raw material for phosphate fertilizer.Therefore,under the background of China’s carbon neutrality goal,it is important to develop the key technologies of waste heat utilization of metallurgical slag and carbon sequestration of metallurgical slag.展开更多
BACKGROUND As the burden of mental disorders among patients with atrial fibrillation(AF)increases,researchers are beginning to pay close attention to the risk and prevalence of these comorbidities.Although studies hav...BACKGROUND As the burden of mental disorders among patients with atrial fibrillation(AF)increases,researchers are beginning to pay close attention to the risk and prevalence of these comorbidities.Although studies have independently analyzed the risk of comorbidity with depression and anxiety in patients with AF,no study has systematically focused on the global epidemiology of these two mental disorders.AIM To explore the prevalence of depression and anxiety in patients with AF.METHODS Five databases were searched from their date of establishment until January 2023.Observational studies reporting the comorbidity of AF with depression and anxiety,were included in this study.Basic information,such as the first author/publication year,study year,study type,and prevalence of depression and anxiety,were extracted.STATA SE 15.1 was used to analyze the data.Subgroup,meta-regression,and sensitivity analyses were performed to estimate study heterogeneity.RESULTS After a thorough search,26 studies were identified and included in this metaanalysis.The prevalence rates of depression and anxiety in adults with AF were 24.3%and 14.5%,respectively.Among adult males with AF,the prevalence was 11.7%and 8.7%,respectively,whereas in females it was 19.8%and 10.1%,respectively.In older adults with AF,the prevalence rates of depression and anxiety were 40.3%and 33.6%,respectively.The highest regional prevalence of depression and anxiety was observed in European(30.2%)and North American(19.8%)patients with AF.CONCLUSION In this study,we found that the prevalence of depression and anxiety among patients with AF varies with sex,region,and evaluation scales,suggesting the need for psychological interventions for patients with AF in clinical practice.展开更多
Penicillium digitatum causes serious losses in postharvest citrus fruit.Exogenous salicylic acid(SA)can induce fruit resistance against various pathogens,but the mechanism remains unclear.Herein,a transcriptome-based ...Penicillium digitatum causes serious losses in postharvest citrus fruit.Exogenous salicylic acid(SA)can induce fruit resistance against various pathogens,but the mechanism remains unclear.Herein,a transcriptome-based approach was used to investigate the underlying mechanism of SA-induced citrus fruit resistance against P.digitatum.We found that CsWRKY70 and genes related to methyl salicylate(MeSA)biosynthesis(salicylate carboxymethyltransferase,SAMT)were induced by exogenous SA.Moreover,significant MeSA accumulation was detected in the SA-treated citrus fruit.The potential involvement of CsWRKY70 in regulating CsSAMT expression in citrus fruit was studied.Subcellular localization,dual luciferase,and electrophoretic mobility shift assays and an analysis of transient expression in fruit peel revealed that the nucleus‐localized transcriptional activator CsWRKY70 can activate the CsSAMT promoter by recognizing the W-box element.Taken together,the findings from this study offer new insights into the transcriptional regulatory mechanism of exogenous SA-induced disease resistance in Citrus sinensis fruit.展开更多
Parameter estimation is analyzed using two kinds of common sampling-type DFRFT(discrete fractional Fourier transform) algorithm. A model of parameter estimation is established. The factors which influence estimation a...Parameter estimation is analyzed using two kinds of common sampling-type DFRFT(discrete fractional Fourier transform) algorithm. A model of parameter estimation is established. The factors which influence estimation accuracy are analyzed. And the simulation is made to verify the conclusions. From the theoretic analysis and simulation verification, it can be drawn that, for the estimation of chirp-rate and initial frequency, Pei's method [10] is more suitable if the absolute value of chirp-rate is small relatively; Ozaktas' method [9] is more suitable if the absolute value of chirp-rate is large relatively; and the two methods are both workable if the absolute value of chirp-rate is moderate. The scope of moderate chirp-rate can be approximately determined as [40 Hz/s, 110 Hz/s].展开更多
Carbon dioxide(CO_2) emission from the rivertype reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled ...Carbon dioxide(CO_2) emission from the rivertype reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled the Three Gorges Reservoir(TGR), a typical river-type reservoir having both river and lake characteristics, using an online system(HydroCTM/CO_2) and YSI-6600v2 meter to determine the partial pressure of carbon dioxide(pCO_2)and physical chemical parameters in 2013. The results showed that the CO_2 flux from the mainstream ranged from 26.1 to 92.2 mg CO_2/m^2h with average CO_2 fluxes of 50.0 mg/m^2h. The CO_2 fluxes from the tributary ranged from-10.91 to 53.95 mg CO_22/mh with area-weighted average CO_2 fluxes of 11.4 mg/m^2h. The main stream emits CO_2 to the atmosphere the whole year; however, the surface water of the tributary can sometimes act as a sink of CO_2 for the atmosphere. As the operation of the TGR, the tributary became more favorable to photosynthetic uptake of CO_2 especially in summer. The total CO_2 flux was estimated to be 0.34 and 0.03 Tg CO_2/year from the mainstream and the tributaries, respectively. Our emission rates are lower than previous estimates, but they are in agreement with the average CO_2 flux from temperate reservoirs estimated by Barros et al.(Nat Geosci 4(9):593–596, 2011).展开更多
Traditional short-time fractional Fourier transform(STFrFT)has a single and fixed window function,which can not be adjusted adaptively according to the characteristics of fre-quency and frequency change rate.In order ...Traditional short-time fractional Fourier transform(STFrFT)has a single and fixed window function,which can not be adjusted adaptively according to the characteristics of fre-quency and frequency change rate.In order to overcome the shortcomings,the STFrFT method with adaptive window function is proposed.In this method,the window function of STFrFT is ad-aptively adjusted by establishing a library containing multiple window functions and taking the minimum information entropy as the criterion,so as to obtain a time-frequency distribution that better matches the desired signal.This method takes into account the time-frequency resolution characteristics of STFrFT and the excellent characteristics of adaptive adjustment to window func-tion,improves the time-frequency aggregation on the basis of eliminating cross term interference,and provides a new tool for improving the time-frequency analysis ability of complex modulated sig-nals.展开更多
The Lake Tian E Zhou(TEZ,an oxbow lake)was formed during the rerouting of the Changjiang River in 1972,with strong influences from the main river channel and flood events.Herein,a sediment core was collected from the ...The Lake Tian E Zhou(TEZ,an oxbow lake)was formed during the rerouting of the Changjiang River in 1972,with strong influences from the main river channel and flood events.Herein,a sediment core was collected from the Lake TEZ for the measurements of carbon isotopes and biomarkers,including stable carbon isotopes(δ13C),radiocarbon composition(?14C),and lignin phenols,as well as lead-210 to reconstruct recent heavy flood events over the past 70 years.At the 24–26 cm interval,the sediment contained the highest OC%,TN%,and lignin phenols content,as well as significantly depleted 13C but enriched 14C,corresponding to the extreme flood event in 1998.In addition,statistics from t-test showed that lignin phenols normalized to OC(Λ8),the concentration of 3,5-dihydroxy benzoic acid(3,5-BD),and the ratio of p-hydroxy benzophenone to total hydroxyl phenols(PHB/HP)were all significantly different between the layers containing flood deposits and the layers deposited under normal non-flood conditions(p<0.05).These results indicate that the later three parameters are highly related to flood events and can be used as compelling proxies,along with sediment chronology,for hydrological changes and storm/flood events in the river basin and coastal marine environments.展开更多
An artificial neural network(ANN) constitutive model is developed for high strength armor steel tempered at 500 C, 600 C and 650 C based on high strain rate data generated from split Hopkinson pressure bar(SHPB) exper...An artificial neural network(ANN) constitutive model is developed for high strength armor steel tempered at 500 C, 600 C and 650 C based on high strain rate data generated from split Hopkinson pressure bar(SHPB) experiments. A new neural network configuration consisting of both training and validation is effectively employed to predict flow stress. Tempering temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on Johnsone Cook(Je C) model and neural network model is performed. It was observed that the developed neural network model could predict flow stress under various strain rates and tempering temperatures. The experimental stressestrain data obtained from high strain rate compression tests using SHPB, over a range of tempering temperatures(500e650 C), strains(0.05e0.2) and strain rates(1000e5500/s) are employed to formulate Je C model to predict the high strain rate deformation behavior of high strength armor steels. The J-C model and the back-propagation ANN model were developed to predict the high strain rate deformation behavior of high strength armor steel and their predictability is evaluated in terms of correlation coefficient(R) and average absolute relative error(AARE). R and AARE for the Je C model are found to be 0.7461 and 27.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. It was observed that the predictions by ANN model are in consistence with the experimental data for all tempering temperatures.展开更多
Visible-light heterogeneous photocatalyst with high activity and selectivity is crucial for the development of organic transformations, but remains a formidable challenge. Herein, a simple and effective strategy was d...Visible-light heterogeneous photocatalyst with high activity and selectivity is crucial for the development of organic transformations, but remains a formidable challenge. Herein, a simple and effective strategy was developed to integrate tetrazine moiety, a visible light active unit, into robust metal-organic frameworks(2D MOF-1(M), M = Co, Mn, Zn, and 3D MOF-2(Co)). MOF-1 series are isomorphous 2D porous frameworks, and MOF-2(Co) displays 3D porous framework. Interestingly, benefiting from the oxidative active species of O_(2)·-, these MOFs all exhibit obviously highly enhanced photocatalytic activities toward the straightforward condensation of o-aminothiophenol and aromatic aldehydes at room temperature in Et OH under visible-white-light irradiation. Notably, compared to 3D MOF, the 2D layered MOF-1(Co) exhibited more excellent catalytic activity with a wide range of substrates possessing preeminent tolerance of steric hindrance. Most impressively, MOF-1(Co) can be recycled at least five times without significant loss of catalytic activity or crystallinity, exhibiting excellent stability and reusability. This study sheds light on the wide-ranging prospects of visible light active 2D MOFs as green photocatalysts for the preparation of fine chemicals.展开更多
Background:Influenza is an acute respiratory infectious disease with a high incidence rate in the Chinese army,which directly disturbs military training and affects soldiers’health.Influenza surveillance systems are ...Background:Influenza is an acute respiratory infectious disease with a high incidence rate in the Chinese army,which directly disturbs military training and affects soldiers’health.Influenza surveillance systems are widely used around the world and play an important role in influenza epidemic prevention and control.Methods:As a theater centers for disease prevention and control,we established an influenza monitoring platform(IMP)in 2014 to strengthen the monitoring of influenza-like illness and influenza virus infection.In this study,we introduced the constitution,influenza virus detection,and quality control for an IMP.The monitoring effect was also evaluated by comparing the monitoring data with data from national influenza surveillance systems.The experiences and problems associated with the platform also were summarized.Results:A theater IMP was established based on 3 levels of medical units,including monitoring sites,testing laboratories and a checking laboratory.A series of measures were taken to guarantee the quality of monitoring,such as technical training,a unified process,sufficient supervision and timely communication.The platform has run smoothly for 3 monitoring years to date.In the 2014–2015 and 2016–2017 monitoring years,sample amount coincided with that obtained from the National Influenza Surveillance program.In the 2015–2016 monitoring year,due to the strict prevention and control measures,an influenza epidemic peak was avoided in monitoring units,and the monitoring data did not coincide with that of the National Influenza Surveillance program.Several problems,including insufficient attention,unreasonable administrative intervention or subordination relationships,and the necessity of detection in monitoring sites were still observed.Conclusion:A theater IMP was established rationally and played a deserved role in the prevention and control of influenza.However,several problems remain to be solved.展开更多
Correlation between the belieal structure and optical activity of two derivatives of R(+)- 1, 1'-binaphthyl-2,2'-diol was derived from a study of their optical rotations, CD curves and Xray crystal structures.
In this study, the yields of unstable chromosome aberrations in human lymphocytes induced by β particles from low-dose HTO have been measured. HTO was mixed with heparinized blood in varying amounts so that a dose of...In this study, the yields of unstable chromosome aberrations in human lymphocytes induced by β particles from low-dose HTO have been measured. HTO was mixed with heparinized blood in varying amounts so that a dose of 6.24 × 10-4 Gy to 1.23 Gy were delivered in 24 and 48 h, respectively. After 72-h culture, the dicentric yield was measured as a function of dose to the blood and compared with data from 60Co γ-radiation. Using a linear-quadratic dose-effect relation to fit the experimental data, a significant linear contribution Y = 0.062D + 0.053D2 was found. The main difference between the coefficients for β and γ-radiation was in the a values, indicating that HTO β-rays were more efficient, particularly at low doses. As per the theory of dual radiation, the relative biological effectiveness (RBE) of HTO β-particles relative to γ-rays is 2.21 at 0.06 Gy and decreases with increasing dose. Micronucleus yield at low doses was fitted to a linear equation Y = C + αD, indicating that the RBE value of MN for HTO β-rays irradiation was between 1.46 and 2.17, which is similar in shape to the chromosome aberrations experiments. Thus, β-rays were found to be more efficient in producing two lesions with single ionizing tracks at low dose.展开更多
The effect of barrier material on AC breakdown voltages of a hybrid gas-solid insulation is investigated by examining the behavior of electrostatic potential on barrier surfaces.Breakdown characteristics of air-insula...The effect of barrier material on AC breakdown voltages of a hybrid gas-solid insulation is investigated by examining the behavior of electrostatic potential on barrier surfaces.Breakdown characteristics of air-insulated gaps with barriers made of three different polymeric materials are experimentally investigated.Further,measurements of surface potential on the barriers are performed and the results are utilized to obtain surface charge dynamic characteristics for the three polymeric materials and extract their electric conductivities,charge carrier mobilities,and trap energy distributions.It is found that the material with the lowest initial surface potential and fastest decay rate exhibits the highest bulk conductivity and carriers'mobility,as well as the lowest trap energy level.These properties provide the highest increase in AC breakdown voltages compared with pure air.It is concluded that materials where the accumulation of charges in the bulk is inhibited and decay of surface charges is facilitated,allow for higher operating voltages of AC hybrid gas-solid insulation systems.The mechanism of the effect of barrier material on AC breakdown voltage is discussed.展开更多
The roles of concealed microproteins encoded by long noncoding RNAs(lncRNAs)are gradually being exposed,but their functions in tumorigenesis are still largely unclear.Here,we identify and characterize a conserved 99-a...The roles of concealed microproteins encoded by long noncoding RNAs(lncRNAs)are gradually being exposed,but their functions in tumorigenesis are still largely unclear.Here,we identify and characterize a conserved 99-amino acid microprotein named KRASIM that is encoded by the putative lncRNA NCBP2-AS2.KRASIM is differentially expressed in normal hepatocytes and hepatocellular carcinoma(HCC)cells and can suppress HCC cell growth and proliferation.Mechanistically,KRASIM interacts and colocalizes with the KRAS protein in the cytoplasm of human HuH-7 hepatoma cells.More importantly,the overexpression of KRASIM decreases the KRAS protein level,leading to the inhibition of ERK signaling activity in HCC cells.These results demonstrate a novel microprotein repressor of the KRAS pathway for the first time and provide new insights into the regulatory mechanisms of oncogenic signaling and HCC therapy.展开更多
The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoel...The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoelectronics. Here, ultrafast epitaxial growth of single-crystal graphene wafers is realized on singlecrystal Cu90Ni10(1 1 1) thin films fabricated by a tailored two-step magnetron sputtering and recrystallization process. The minor nickel(Ni) content greatly enhances the catalytic activity of Cu, rendering the growth of a 4 in. single-crystal monolayer graphene wafer in 10 min on Cu90Ni10(1 1 1), 50 folds faster than graphene growth on Cu(1 1 1). Through the carbon isotope labeling experiments, graphene growth on Cu90Ni10(1 1 1) is proved to be exclusively surface-reaction dominated, which is ascribed to the Cu surface enrichment in the Cu Ni alloy, as indicated by element in-depth profile. One of the best benefits of our protocol is the compatibility with wafer process and excellent scalability. A pilot-scale chemical vapor deposition(CVD) system is designed and built for the mass production of single-crystal graphene wafers, with productivity of 25 pieces in one process cycle. Furthermore, we demonstrate the application of single-crystal graphene in electrically controlled liquid-crystal microlens arrays(LCMLA), which exhibit highly tunable focal lengths near 2 mm under small driving voltages. By integration of the graphene based LCMLA and a CMOS sensor, a prototype camera is proposed that is available for simultaneous light-field and light intensity imaging. The single-crystal graphene wafers could hold great promising for highperformance electronics and optoelectronics that are compatible with wafer process.展开更多
New types of antimicrobial systems are urgently needed owing to the emergence of pathogenic microbial strains that gain resistance to antibiotics commonly used in daily life and medical care. In this study we develope...New types of antimicrobial systems are urgently needed owing to the emergence of pathogenic microbial strains that gain resistance to antibiotics commonly used in daily life and medical care. In this study we developed for the first time a broad-spectrum and robust antimicrobial thin film coating based on large-area chemical vapor deposition （CVD）-grown graphene-wrapped silver nanowires （AgNWs）. The antimicrobial graphene/AgNW hybrid coating can be applied on commerdal flexible transparent ethylene vinyl acetate/polyethylene terephthalate （EVA/PET） plastic films by a full roll-to-roll process. The graphene/AgNW hybrid coating showed broad-spectrum antimicrobial activity against Gram-negative （Escherichia coli） and Gram-positive bacteria （Staphylococcus aureus）, and fungi （Candida albicans）. This effect was attributed to a weaker microbial attachment to the ultra-smooth graphene film and the sterilization capacity of Ag＋, which is sustainably released from the AgNWs and presumably enhanced by the electrochemical corrosion of AgNWs. Moreover, the robust antimicrobial activity of the graphene/AgNW coating was reinforced by AgNW encapsulation by graphene. Furthermore, the antimicrobial efficiency could be enhanced to -100% by water electrolysis by using the conductive graphene/AgNW coating as a cathode. We developed a transparent and flexible antimicrobial cover made of graphene/AgNW/EVA/PET and an antimicrobial denture coated by graphene/ AgNW, to show the potential applications of the antimicrobial materials.展开更多
The relation between ocean internal waves (IWs) and surface fluctuation is studied using a quasiincompressible two-dimensional linear ocean wave model.The main conclusions are as follows: the IW parameters can be obta...The relation between ocean internal waves (IWs) and surface fluctuation is studied using a quasiincompressible two-dimensional linear ocean wave model.The main conclusions are as follows: the IW parameters can be obtained by solving the boundary value problem of ordinary differential equations with the frequency,wave number,and amplitude of the surface fluctuation.When the ocean surface fluctuation state is given,the ocean IW presents a different structure,i.e.,the uncertainty of the solution,which reflects the characteristics of the inverse problem.To obtain a definite solution,this study proposes constraint conditions for the inverse problem,namely,the relationship among background flow,buoyancy frequency,sea surface height,and geostrophic parameters.The necessary and sufficient conditions for the existence of IWs and external waves (surface wave) can be obtained according to the different constraint conditions.The amplitude of the surface fluctuation is positively correlated with IWs,and they share the same frequency and wave number.We also examined the relationship between the vertical structure,the maximum amplitude,and the constraint conditions.For a certain wave number,when the ocean environment is defined,the natural frequency (characteristic frequency) of IWs can be obtained.If the frequency of the surface fluctuation is similar or equal to the natural frequency,the resonance phenomenon will occur and can result in very strong IWs.The presented theory can serve as a basis for the analytical estimation of IWs.展开更多
Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive...Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive.Here,a pan-cancer transcriptomic screening for 10852 samples of 33 TCGA cancer types reveals that cAMP-responsive element(CRE)transcription factors are convergent activators for cancer stemness.Deconvolution of transcriptomic profiles,specification of neural markers and illustration of norepinephrine dynamics uncover a bond between TME neural signals and cancer-cell CRE activity.Specifically,neural signal norepinephrine potentiates the stemness of proximal cancer cells by activating cAMP-CRE axis,where ATF1 serves as a conserved hub.Upon activation by norepinephrine,ATF1 potentiates cancer stemness by coordinated trans-activation of both nuclear pluripotency factors MYC/NANOG and mitochondrial biogenesis regulators NRF1/TFAM,thereby orchestrating nuclear reprograming and mitochondrial rejuvenating.Accordingly,single-cell transcriptomes confirm the coordinated activation of nuclear pluripotency with mitochondrial biogenesis in cancer stem-like cells.These findings elucidate that cancer cell acquires stemness via a norepinephrine-ATF1 driven nucleus-mitochondria collaborated program,suggesting a spatialized stemness acquisition by hijacking microenvironmental neural signals.展开更多
In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The str...In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains, which can significantly affect the performance of the graphene films and impede their industrial applications. Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation. Although the bicrystal has been widely investigated for traditional bulk materials, no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals. In this stud34 we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu （100） substrate. Control of the density of the GBs with a miso- rientation angle of 30° was realized via the controllable rapid growth of sub- centimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment. The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.展开更多
Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphen...Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphene is therefore highly desired yet still suffers from a slow growth rate and poor layer uniformity.Meanwhile,graphene wrinkles,including folds and ripples,form during cooling due to the thermal contraction mismatch between graphene and the metal substrates,and have been far from suppressed or eliminated,especially in bilayer graphene,which would greatly degrade the extraordinary properties of graphene.Here we report the ultrafast growth of wafer-scale fold-free bilayer graphene by chemical vapor deposition.Through well-tuning the alloy thickness and strain regulation of the single-crystal CuNi(111)/sapphire,the full coverage of a 2-inch fold-free bilayer graphene wafer via mainly isothermal segregation has been achieved as fast as 30 s.The tensile-strained CuNi(111)film reduces the thermal contraction mismatch and suppresses the formation of graphene folds during cooling,which is directly observed through in situ optical microscopy.The ultraflat bilayer graphene exhibits wafer-scale uniformity in electrical performance and enhanced mechanical property comparable to the exfoliated ones.Our results offer a promising route for largescale production of bilayer graphene and enable its various applications.展开更多
基金supported by the following funds:Guizhou Science and Technology Support Program Project[Grant No.Guizhou Science and Technology Cooperation Support(2025)General 079]Guizhou Provincial Department of Education’s"Top 100 Schools and Thousand Enterprises in Science andTechnology Research and Development"Project in 2025(Contract Number:Guizhou Education and Technology[2025]No.009)+6 种基金Hebei Province Innovation Ability Improvement Plan(No.23561001D)Hebei Provincial Natural Science Foundation(No.H2022209089)Open Fund Project of the Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(Grant No.FMRUlab23-03)the National Natural Science Foundation of China(No.52074128)Basic Scientific Research Business Expenses of Colleges and Universities in Hebei Province(Nos.JYG2022001 and JQN2023008)Tangshan Talent Funding Project(No.A202202007),Natural Science Foundation of Hebei Province(No.E2023209107)Foundation of Tangshan Science and Technology Bureau(No.23150219A).
文摘Metallurgical slag is a waste or by-product of the metallurgical process,and its improper disposal can pose negative environmental impacts,including groundwater and soil contamination.The composition and properties of metallurgical slag are complex,which is usually difficult to use or process directly and requires special treatment and utilization methods.Taking converter slag and blast furnace slag as examples,the research frontiers and development potential were primarily discussed and analyzed in three aspects:the recycling within and outside metallurgical slag plants,the extraction and utilization of thermal energy from metallurgical slag,and the functionalization and social application of metallurgical slag.The metallurgical slag waste heat recovery includes chemical methods and physical methods.Among them,the physical method currently most used was centrifugal granulation to recover heat.Chemical laws could recover hydrogen through the waste heat of metallurgical slag,which could save fuel and reduce CO_(2) generated by fuel combustion.Metallurgical slag is rich in alkaline metal oxides,which can undergo a carbonation reaction with CO_(2) to achieve carbon sequestration in metallurgical slag.Elements such as iron,phosphorus,and silicon contained in metallurgical slag could be used in soil conditioners,cement raw materials,and wastewater treatment.For example,the phosphorus element in the slag could be extracted by melt modification followed by acid leaching and used as a raw material for phosphate fertilizer.Therefore,under the background of China’s carbon neutrality goal,it is important to develop the key technologies of waste heat utilization of metallurgical slag and carbon sequestration of metallurgical slag.
基金Supported by the Fourth Batch of National Excellent Talents in Chinese Medicine Project,No.Lh01.40.002the Third Batch of Excellent Young Talents Clinical Competency Enhancement Program of Longhua Hospital,No.RC-2020-01-12.
文摘BACKGROUND As the burden of mental disorders among patients with atrial fibrillation(AF)increases,researchers are beginning to pay close attention to the risk and prevalence of these comorbidities.Although studies have independently analyzed the risk of comorbidity with depression and anxiety in patients with AF,no study has systematically focused on the global epidemiology of these two mental disorders.AIM To explore the prevalence of depression and anxiety in patients with AF.METHODS Five databases were searched from their date of establishment until January 2023.Observational studies reporting the comorbidity of AF with depression and anxiety,were included in this study.Basic information,such as the first author/publication year,study year,study type,and prevalence of depression and anxiety,were extracted.STATA SE 15.1 was used to analyze the data.Subgroup,meta-regression,and sensitivity analyses were performed to estimate study heterogeneity.RESULTS After a thorough search,26 studies were identified and included in this metaanalysis.The prevalence rates of depression and anxiety in adults with AF were 24.3%and 14.5%,respectively.Among adult males with AF,the prevalence was 11.7%and 8.7%,respectively,whereas in females it was 19.8%and 10.1%,respectively.In older adults with AF,the prevalence rates of depression and anxiety were 40.3%and 33.6%,respectively.The highest regional prevalence of depression and anxiety was observed in European(30.2%)and North American(19.8%)patients with AF.CONCLUSION In this study,we found that the prevalence of depression and anxiety among patients with AF varies with sex,region,and evaluation scales,suggesting the need for psychological interventions for patients with AF in clinical practice.
基金supported by the National Natural Science Foundation of China(Grant numbers 31772027 and 31972126).
文摘Penicillium digitatum causes serious losses in postharvest citrus fruit.Exogenous salicylic acid(SA)can induce fruit resistance against various pathogens,but the mechanism remains unclear.Herein,a transcriptome-based approach was used to investigate the underlying mechanism of SA-induced citrus fruit resistance against P.digitatum.We found that CsWRKY70 and genes related to methyl salicylate(MeSA)biosynthesis(salicylate carboxymethyltransferase,SAMT)were induced by exogenous SA.Moreover,significant MeSA accumulation was detected in the SA-treated citrus fruit.The potential involvement of CsWRKY70 in regulating CsSAMT expression in citrus fruit was studied.Subcellular localization,dual luciferase,and electrophoretic mobility shift assays and an analysis of transient expression in fruit peel revealed that the nucleus‐localized transcriptional activator CsWRKY70 can activate the CsSAMT promoter by recognizing the W-box element.Taken together,the findings from this study offer new insights into the transcriptional regulatory mechanism of exogenous SA-induced disease resistance in Citrus sinensis fruit.
基金the National Natural Science Foundation of China (60902054)China Postdoctora Science Foundation (201003758, 20090460114) "Taishan Scholars" Special Foundation of Shandong Province for the support
文摘Parameter estimation is analyzed using two kinds of common sampling-type DFRFT(discrete fractional Fourier transform) algorithm. A model of parameter estimation is established. The factors which influence estimation accuracy are analyzed. And the simulation is made to verify the conclusions. From the theoretic analysis and simulation verification, it can be drawn that, for the estimation of chirp-rate and initial frequency, Pei's method [10] is more suitable if the absolute value of chirp-rate is small relatively; Ozaktas' method [9] is more suitable if the absolute value of chirp-rate is large relatively; and the two methods are both workable if the absolute value of chirp-rate is moderate. The scope of moderate chirp-rate can be approximately determined as [40 Hz/s, 110 Hz/s].
基金funded by the National Natural Science Foundation of China (No.41573064)The National Key Research and Development Program of China (No.2016YFA0601003)the Special S&T Project on Treatment and Control of Water Pollution (No.2012ZX07104-001)
文摘Carbon dioxide(CO_2) emission from the rivertype reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled the Three Gorges Reservoir(TGR), a typical river-type reservoir having both river and lake characteristics, using an online system(HydroCTM/CO_2) and YSI-6600v2 meter to determine the partial pressure of carbon dioxide(pCO_2)and physical chemical parameters in 2013. The results showed that the CO_2 flux from the mainstream ranged from 26.1 to 92.2 mg CO_2/m^2h with average CO_2 fluxes of 50.0 mg/m^2h. The CO_2 fluxes from the tributary ranged from-10.91 to 53.95 mg CO_22/mh with area-weighted average CO_2 fluxes of 11.4 mg/m^2h. The main stream emits CO_2 to the atmosphere the whole year; however, the surface water of the tributary can sometimes act as a sink of CO_2 for the atmosphere. As the operation of the TGR, the tributary became more favorable to photosynthetic uptake of CO_2 especially in summer. The total CO_2 flux was estimated to be 0.34 and 0.03 Tg CO_2/year from the mainstream and the tributaries, respectively. Our emission rates are lower than previous estimates, but they are in agreement with the average CO_2 flux from temperate reservoirs estimated by Barros et al.(Nat Geosci 4(9):593–596, 2011).
基金supported by the National Natural Science Found-ation of China(No.61571454)Special Fund for Taishan Scholar Project(No.201712072)。
文摘Traditional short-time fractional Fourier transform(STFrFT)has a single and fixed window function,which can not be adjusted adaptively according to the characteristics of fre-quency and frequency change rate.In order to overcome the shortcomings,the STFrFT method with adaptive window function is proposed.In this method,the window function of STFrFT is ad-aptively adjusted by establishing a library containing multiple window functions and taking the minimum information entropy as the criterion,so as to obtain a time-frequency distribution that better matches the desired signal.This method takes into account the time-frequency resolution characteristics of STFrFT and the excellent characteristics of adaptive adjustment to window func-tion,improves the time-frequency aggregation on the basis of eliminating cross term interference,and provides a new tool for improving the time-frequency analysis ability of complex modulated sig-nals.
基金The National Natural Science Foundation of China under contract Nos 41021064,41276081 and 41606211the 111 Project under contract No.B08022the Scientific Research Fund of Second Institute of Oceanography,MNR under contract No.JG1806
文摘The Lake Tian E Zhou(TEZ,an oxbow lake)was formed during the rerouting of the Changjiang River in 1972,with strong influences from the main river channel and flood events.Herein,a sediment core was collected from the Lake TEZ for the measurements of carbon isotopes and biomarkers,including stable carbon isotopes(δ13C),radiocarbon composition(?14C),and lignin phenols,as well as lead-210 to reconstruct recent heavy flood events over the past 70 years.At the 24–26 cm interval,the sediment contained the highest OC%,TN%,and lignin phenols content,as well as significantly depleted 13C but enriched 14C,corresponding to the extreme flood event in 1998.In addition,statistics from t-test showed that lignin phenols normalized to OC(Λ8),the concentration of 3,5-dihydroxy benzoic acid(3,5-BD),and the ratio of p-hydroxy benzophenone to total hydroxyl phenols(PHB/HP)were all significantly different between the layers containing flood deposits and the layers deposited under normal non-flood conditions(p<0.05).These results indicate that the later three parameters are highly related to flood events and can be used as compelling proxies,along with sediment chronology,for hydrological changes and storm/flood events in the river basin and coastal marine environments.
文摘An artificial neural network(ANN) constitutive model is developed for high strength armor steel tempered at 500 C, 600 C and 650 C based on high strain rate data generated from split Hopkinson pressure bar(SHPB) experiments. A new neural network configuration consisting of both training and validation is effectively employed to predict flow stress. Tempering temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on Johnsone Cook(Je C) model and neural network model is performed. It was observed that the developed neural network model could predict flow stress under various strain rates and tempering temperatures. The experimental stressestrain data obtained from high strain rate compression tests using SHPB, over a range of tempering temperatures(500e650 C), strains(0.05e0.2) and strain rates(1000e5500/s) are employed to formulate Je C model to predict the high strain rate deformation behavior of high strength armor steels. The J-C model and the back-propagation ANN model were developed to predict the high strain rate deformation behavior of high strength armor steel and their predictability is evaluated in terms of correlation coefficient(R) and average absolute relative error(AARE). R and AARE for the Je C model are found to be 0.7461 and 27.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. It was observed that the predictions by ANN model are in consistence with the experimental data for all tempering temperatures.
基金financially supported by the National Natural Science Foundation of China (Nos. 22171223, 22077099 and 21531007)the Innovation Capability Support Program of Shaanxi (Nos. 2023-CX-TD-75 and 2022KJXX-32)+2 种基金the Natural Science Foundation of Shaanxi Province of China (Nos. 2020TG-031, 2022JQ125, 2023-JC-YB-141, 2022JQ-151 and 2021JQ-440)the special fund of Shaanxi Key Laboratory of Special Fuel Chemistry and Material (No. SPCF-SKL-2021-0011)Young Talent Fund of Association for Science and Technology in Shaanxi, China (No. SWYY202206)。
文摘Visible-light heterogeneous photocatalyst with high activity and selectivity is crucial for the development of organic transformations, but remains a formidable challenge. Herein, a simple and effective strategy was developed to integrate tetrazine moiety, a visible light active unit, into robust metal-organic frameworks(2D MOF-1(M), M = Co, Mn, Zn, and 3D MOF-2(Co)). MOF-1 series are isomorphous 2D porous frameworks, and MOF-2(Co) displays 3D porous framework. Interestingly, benefiting from the oxidative active species of O_(2)·-, these MOFs all exhibit obviously highly enhanced photocatalytic activities toward the straightforward condensation of o-aminothiophenol and aromatic aldehydes at room temperature in Et OH under visible-white-light irradiation. Notably, compared to 3D MOF, the 2D layered MOF-1(Co) exhibited more excellent catalytic activity with a wide range of substrates possessing preeminent tolerance of steric hindrance. Most impressively, MOF-1(Co) can be recycled at least five times without significant loss of catalytic activity or crystallinity, exhibiting excellent stability and reusability. This study sheds light on the wide-ranging prospects of visible light active 2D MOFs as green photocatalysts for the preparation of fine chemicals.
文摘Background:Influenza is an acute respiratory infectious disease with a high incidence rate in the Chinese army,which directly disturbs military training and affects soldiers’health.Influenza surveillance systems are widely used around the world and play an important role in influenza epidemic prevention and control.Methods:As a theater centers for disease prevention and control,we established an influenza monitoring platform(IMP)in 2014 to strengthen the monitoring of influenza-like illness and influenza virus infection.In this study,we introduced the constitution,influenza virus detection,and quality control for an IMP.The monitoring effect was also evaluated by comparing the monitoring data with data from national influenza surveillance systems.The experiences and problems associated with the platform also were summarized.Results:A theater IMP was established based on 3 levels of medical units,including monitoring sites,testing laboratories and a checking laboratory.A series of measures were taken to guarantee the quality of monitoring,such as technical training,a unified process,sufficient supervision and timely communication.The platform has run smoothly for 3 monitoring years to date.In the 2014–2015 and 2016–2017 monitoring years,sample amount coincided with that obtained from the National Influenza Surveillance program.In the 2015–2016 monitoring year,due to the strict prevention and control measures,an influenza epidemic peak was avoided in monitoring units,and the monitoring data did not coincide with that of the National Influenza Surveillance program.Several problems,including insufficient attention,unreasonable administrative intervention or subordination relationships,and the necessity of detection in monitoring sites were still observed.Conclusion:A theater IMP was established rationally and played a deserved role in the prevention and control of influenza.However,several problems remain to be solved.
文摘Correlation between the belieal structure and optical activity of two derivatives of R(+)- 1, 1'-binaphthyl-2,2'-diol was derived from a study of their optical rotations, CD curves and Xray crystal structures.
文摘In this study, the yields of unstable chromosome aberrations in human lymphocytes induced by β particles from low-dose HTO have been measured. HTO was mixed with heparinized blood in varying amounts so that a dose of 6.24 × 10-4 Gy to 1.23 Gy were delivered in 24 and 48 h, respectively. After 72-h culture, the dicentric yield was measured as a function of dose to the blood and compared with data from 60Co γ-radiation. Using a linear-quadratic dose-effect relation to fit the experimental data, a significant linear contribution Y = 0.062D + 0.053D2 was found. The main difference between the coefficients for β and γ-radiation was in the a values, indicating that HTO β-rays were more efficient, particularly at low doses. As per the theory of dual radiation, the relative biological effectiveness (RBE) of HTO β-particles relative to γ-rays is 2.21 at 0.06 Gy and decreases with increasing dose. Micronucleus yield at low doses was fitted to a linear equation Y = C + αD, indicating that the RBE value of MN for HTO β-rays irradiation was between 1.46 and 2.17, which is similar in shape to the chromosome aberrations experiments. Thus, β-rays were found to be more efficient in producing two lesions with single ionizing tracks at low dose.
基金supported by the National Natural Science Foundation of China(51607041)China State Key Lab of Power Systems(SKLD19KM06)。
文摘The effect of barrier material on AC breakdown voltages of a hybrid gas-solid insulation is investigated by examining the behavior of electrostatic potential on barrier surfaces.Breakdown characteristics of air-insulated gaps with barriers made of three different polymeric materials are experimentally investigated.Further,measurements of surface potential on the barriers are performed and the results are utilized to obtain surface charge dynamic characteristics for the three polymeric materials and extract their electric conductivities,charge carrier mobilities,and trap energy distributions.It is found that the material with the lowest initial surface potential and fastest decay rate exhibits the highest bulk conductivity and carriers'mobility,as well as the lowest trap energy level.These properties provide the highest increase in AC breakdown voltages compared with pure air.It is concluded that materials where the accumulation of charges in the bulk is inhibited and decay of surface charges is facilitated,allow for higher operating voltages of AC hybrid gas-solid insulation systems.The mechanism of the effect of barrier material on AC breakdown voltage is discussed.
基金This work was supported by the National Key Research and Development Program of China(2017YFA0504400)the National Natural Science Foundation of China(31370791,31671349,31770879)+2 种基金Fundamental Research Funds for the Central Universities(14lgjc18)This research was supported in part by the Guangdong Province Key Laboratory of Computational Science(13lgjc05)the Guangdong Province Computational Science Innovative Research Team(14lgjc18).
文摘The roles of concealed microproteins encoded by long noncoding RNAs(lncRNAs)are gradually being exposed,but their functions in tumorigenesis are still largely unclear.Here,we identify and characterize a conserved 99-amino acid microprotein named KRASIM that is encoded by the putative lncRNA NCBP2-AS2.KRASIM is differentially expressed in normal hepatocytes and hepatocellular carcinoma(HCC)cells and can suppress HCC cell growth and proliferation.Mechanistically,KRASIM interacts and colocalizes with the KRAS protein in the cytoplasm of human HuH-7 hepatoma cells.More importantly,the overexpression of KRASIM decreases the KRAS protein level,leading to the inhibition of ERK signaling activity in HCC cells.These results demonstrate a novel microprotein repressor of the KRAS pathway for the first time and provide new insights into the regulatory mechanisms of oncogenic signaling and HCC therapy.
基金supported by the National Basic Research Program of China(2016YFA0200101 and 2014CB932500)the National Natural Science Foundation of China(21525310,51432002,51520105003,61432007,and 61176052)Beijing Municipal Science&Technology Commission(Z161100002116021 and Z181100004818001)
文摘The scalable growth of wafer-sized single-crystal graphene in an energy-efficient manner and compatible with wafer process is critical for the killer applications of graphene in high-performance electronics and optoelectronics. Here, ultrafast epitaxial growth of single-crystal graphene wafers is realized on singlecrystal Cu90Ni10(1 1 1) thin films fabricated by a tailored two-step magnetron sputtering and recrystallization process. The minor nickel(Ni) content greatly enhances the catalytic activity of Cu, rendering the growth of a 4 in. single-crystal monolayer graphene wafer in 10 min on Cu90Ni10(1 1 1), 50 folds faster than graphene growth on Cu(1 1 1). Through the carbon isotope labeling experiments, graphene growth on Cu90Ni10(1 1 1) is proved to be exclusively surface-reaction dominated, which is ascribed to the Cu surface enrichment in the Cu Ni alloy, as indicated by element in-depth profile. One of the best benefits of our protocol is the compatibility with wafer process and excellent scalability. A pilot-scale chemical vapor deposition(CVD) system is designed and built for the mass production of single-crystal graphene wafers, with productivity of 25 pieces in one process cycle. Furthermore, we demonstrate the application of single-crystal graphene in electrically controlled liquid-crystal microlens arrays(LCMLA), which exhibit highly tunable focal lengths near 2 mm under small driving voltages. By integration of the graphene based LCMLA and a CMOS sensor, a prototype camera is proposed that is available for simultaneous light-field and light intensity imaging. The single-crystal graphene wafers could hold great promising for highperformance electronics and optoelectronics that are compatible with wafer process.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 81000441, 21222303, and 21173004）, the National Basic Research Program of China （Nos. 2014CB932500）, and National Program for Support of Top-Notch Young Professionals.
文摘New types of antimicrobial systems are urgently needed owing to the emergence of pathogenic microbial strains that gain resistance to antibiotics commonly used in daily life and medical care. In this study we developed for the first time a broad-spectrum and robust antimicrobial thin film coating based on large-area chemical vapor deposition （CVD）-grown graphene-wrapped silver nanowires （AgNWs）. The antimicrobial graphene/AgNW hybrid coating can be applied on commerdal flexible transparent ethylene vinyl acetate/polyethylene terephthalate （EVA/PET） plastic films by a full roll-to-roll process. The graphene/AgNW hybrid coating showed broad-spectrum antimicrobial activity against Gram-negative （Escherichia coli） and Gram-positive bacteria （Staphylococcus aureus）, and fungi （Candida albicans）. This effect was attributed to a weaker microbial attachment to the ultra-smooth graphene film and the sterilization capacity of Ag＋, which is sustainably released from the AgNWs and presumably enhanced by the electrochemical corrosion of AgNWs. Moreover, the robust antimicrobial activity of the graphene/AgNW coating was reinforced by AgNW encapsulation by graphene. Furthermore, the antimicrobial efficiency could be enhanced to -100% by water electrolysis by using the conductive graphene/AgNW coating as a cathode. We developed a transparent and flexible antimicrobial cover made of graphene/AgNW/EVA/PET and an antimicrobial denture coated by graphene/ AgNW, to show the potential applications of the antimicrobial materials.
文摘The relation between ocean internal waves (IWs) and surface fluctuation is studied using a quasiincompressible two-dimensional linear ocean wave model.The main conclusions are as follows: the IW parameters can be obtained by solving the boundary value problem of ordinary differential equations with the frequency,wave number,and amplitude of the surface fluctuation.When the ocean surface fluctuation state is given,the ocean IW presents a different structure,i.e.,the uncertainty of the solution,which reflects the characteristics of the inverse problem.To obtain a definite solution,this study proposes constraint conditions for the inverse problem,namely,the relationship among background flow,buoyancy frequency,sea surface height,and geostrophic parameters.The necessary and sufficient conditions for the existence of IWs and external waves (surface wave) can be obtained according to the different constraint conditions.The amplitude of the surface fluctuation is positively correlated with IWs,and they share the same frequency and wave number.We also examined the relationship between the vertical structure,the maximum amplitude,and the constraint conditions.For a certain wave number,when the ocean environment is defined,the natural frequency (characteristic frequency) of IWs can be obtained.If the frequency of the surface fluctuation is similar or equal to the natural frequency,the resonance phenomenon will occur and can result in very strong IWs.The presented theory can serve as a basis for the analytical estimation of IWs.
基金This research work was supported by the National Key R&D Program of China(2019YFA0110300 to Q.L.)the National Natural Science Foundation of China(No.82003096 to R.G.,No.82002943 to B.H.,No.81820108024 to Q.L.and No.81972594 to M.Y.)+1 种基金the Natural Science Foundation of Guangdong(2017A030313608 to Q.L.)the Science and Technology Planning Project of Guangzhou(201804020044 to Q.L.).
文摘Cancer cell receives extracellular signal inputs to obtain a stem-like status,yet how tumor microenvironmental(TME)neural signals steer cancer stemness to establish the hierarchical tumor architectures remains elusive.Here,a pan-cancer transcriptomic screening for 10852 samples of 33 TCGA cancer types reveals that cAMP-responsive element(CRE)transcription factors are convergent activators for cancer stemness.Deconvolution of transcriptomic profiles,specification of neural markers and illustration of norepinephrine dynamics uncover a bond between TME neural signals and cancer-cell CRE activity.Specifically,neural signal norepinephrine potentiates the stemness of proximal cancer cells by activating cAMP-CRE axis,where ATF1 serves as a conserved hub.Upon activation by norepinephrine,ATF1 potentiates cancer stemness by coordinated trans-activation of both nuclear pluripotency factors MYC/NANOG and mitochondrial biogenesis regulators NRF1/TFAM,thereby orchestrating nuclear reprograming and mitochondrial rejuvenating.Accordingly,single-cell transcriptomes confirm the coordinated activation of nuclear pluripotency with mitochondrial biogenesis in cancer stem-like cells.These findings elucidate that cancer cell acquires stemness via a norepinephrine-ATF1 driven nucleus-mitochondria collaborated program,suggesting a spatialized stemness acquisition by hijacking microenvironmental neural signals.
基金Acknowledgements We acknowledge financial support from the National Natural Science Foundation of China （Nos. 21173004, 51520105003, 51432002, 21222303 and 51362029） and the National Basic Research Program of China （Nos. 2014CB932500, 2013CB932603, 2012CB933404, 2011CB933003, and 2011CB921904）, the National Program for Support of Top-Notch Young Professionals, and Beijing Municipal Science ＆ Technology Commission （No. Z161100002116002）.
文摘In the chemical vapor deposition growth of large-area graphene polycrystalline thin films, the coalescence of randomly oriented graphene domains results in a high density of uncertain grain boundaries （GBs）. The structures and properties of various GBs are highly dependent on the misorientation angles between the graphene domains, which can significantly affect the performance of the graphene films and impede their industrial applications. Graphene bicrystals with a specific type of GB can be synthesized via the controllable growth of graphene domains with a predefined lattice orientation. Although the bicrystal has been widely investigated for traditional bulk materials, no successful synthesis strategy has been presented for growing two-dimensional graphene bicrystals. In this stud34 we demonstrate a simple approach for growing well-aligned large-domain graphene bicrystals with a confined tilt angle of 30° on a facilely recrystallized single-crystal Cu （100） substrate. Control of the density of the GBs with a miso- rientation angle of 30° was realized via the controllable rapid growth of sub- centimeter graphene domains with the assistance of a cooperative catalytic surface-passivation treatment. The large-area production of graphene bicrystals consisting of the sole specific GBs with a tunable density provides a new material platform for fundamental studies and practical applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.52021006,T2188101,and 22105009)Beijing National Laboratory for Molecular Sciences(No.BNLMSCXTD-202001)+1 种基金the Tencent Foundation(No.XPLORER PRIZE)We acknowledge Molecular Materials and Nanofabrication Laboratory(MMNL)in the College of Chemistry at Peking University for the use of instruments.
文摘Bilayer graphene provides a versatile platform for exploring a variety of intriguing phenomena and shows much promise for applications in electronics,optoelectronics,etc.Controlled growth of large-area bilayer graphene is therefore highly desired yet still suffers from a slow growth rate and poor layer uniformity.Meanwhile,graphene wrinkles,including folds and ripples,form during cooling due to the thermal contraction mismatch between graphene and the metal substrates,and have been far from suppressed or eliminated,especially in bilayer graphene,which would greatly degrade the extraordinary properties of graphene.Here we report the ultrafast growth of wafer-scale fold-free bilayer graphene by chemical vapor deposition.Through well-tuning the alloy thickness and strain regulation of the single-crystal CuNi(111)/sapphire,the full coverage of a 2-inch fold-free bilayer graphene wafer via mainly isothermal segregation has been achieved as fast as 30 s.The tensile-strained CuNi(111)film reduces the thermal contraction mismatch and suppresses the formation of graphene folds during cooling,which is directly observed through in situ optical microscopy.The ultraflat bilayer graphene exhibits wafer-scale uniformity in electrical performance and enhanced mechanical property comparable to the exfoliated ones.Our results offer a promising route for largescale production of bilayer graphene and enable its various applications.
