As climacteric fruits,Mangoes are highly susceptible to spoilage and quality deterioration due to ethylene exposure.Protein-based nanofibers can potentially adsorb ethylene,but their stability in ethylene removal is o...As climacteric fruits,Mangoes are highly susceptible to spoilage and quality deterioration due to ethylene exposure.Protein-based nanofibers can potentially adsorb ethylene,but their stability in ethylene removal is often insufficient for practical applications.This study employs electrospinning to fabricate zein-based twodimensional network nanofiber films(T/N/Z films).The combination of zein and the two-dimensional network structure enhances ethylene adsorption efficiency through active functional groups and a high specific surface area.The addition of NaCl(N)and Tween 80(T)helps induce fiber splitting,reduce surface tension,and strengthen hydrogen bonding,imparting a network morphology to the material.The ethylene adsorption efficiency of the 0.7%T/N/Z films was 27.91±1.55 mg m^(-3)·h^(-1),significantly higher than that of the control group.Mango preservation experiments demonstrated that the 0.7%T/N/Z films reduced browning(2.70±2.42%)and increased fruit hardness(804.23±65.54 g)compared to all other treatments,extending the storage period by over 20 days.展开更多
Although electrostatic bonding between chalcogen(Ch)atoms(O,S,Se,and Te)and nitrogen(N)has emerged as a powerful driving force in the fabrication of supramolecular structures;this noncovalent bond has not yet been use...Although electrostatic bonding between chalcogen(Ch)atoms(O,S,Se,and Te)and nitrogen(N)has emerged as a powerful driving force in the fabrication of supramolecular structures;this noncovalent bond has not yet been used to link polymers to form networks.In this study,we took advantage of additive enthalpy in forming multipoint noncovalent bonds to construct a two-dimensional(2D)network via the hierarchical on-surface synthesis of linear polymer chains,followed by multipoint S···N and S···H bonding.When 4,7-dibromobenzo[c][1,2,5]thiadiazole was used,only short oligomers with embedded bromine atoms and cross-linked byproducts were formed on Ag(111)or Au(111)surfaces after multiple annealing procedures,and no 2D network was observed.By changing the precursor to a similar iodinesubstituted molecule,long linear polymers were generated and assembled with iodine atoms on Au(111)after annealing at 523 K.After annealing at 603 K,iodine atoms were desorbed and polymer chains were assembled via multipoint noncovalent bonding.The 2D network remained intact after annealing at 653 K,demonstrating its high thermostability.The multipoint noncovalent bonds were investigated by the combination of scanning tunneling microscopy,noncontact atomic force microscopy,and density functional theory calculations,which revealed that S···N and S···H bonding were the driving forces to construct thermostable and orderly 2D networks.展开更多
Solvothermal reactions of 3-(3-methylpyridin-4-yl)benzoic acid (Hmpba) with Zn(Ⅱ),Cd(Ⅱ),or Cu(Ⅱ) salts yielded crystals of coordination polymers [Zn(mpba)_(2)] (1),[Cd(mpba)_(2)] (2),and [Cu(mpba)_(2)]·vip (...Solvothermal reactions of 3-(3-methylpyridin-4-yl)benzoic acid (Hmpba) with Zn(Ⅱ),Cd(Ⅱ),or Cu(Ⅱ) salts yielded crystals of coordination polymers [Zn(mpba)_(2)] (1),[Cd(mpba)_(2)] (2),and [Cu(mpba)_(2)]·vip (3·g),respectively,possessing two-dimensional (2D) 4-connected sql coordination networks with different packing/interpenetration modes.1 and 2 both possess close-packing two-fold interpenetrated sql nets,but the ligand orientations in their single layers and the stacking manners of their double layers are quite different and have an inversed trend of complexity.The sql nets in 3 are non-interpenetrated,which loosely pack to give a porous structure with 1D channels.Interestingly,1–3 have a completely inversed trend in packing/interpenetration and porosity,compared to the coordination networks constructed by the same metal ions and the ligand without the methyl group (3-(pyridin-4-yl)benzoic acid).The porous framework of 3 can be retained after vip removal,as demonstrated by the CO_(2)adsorption isotherms and high catalytic performances for cycloaddition of epoxides and CO_(2).展开更多
The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogo...The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.展开更多
As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and el...As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.展开更多
Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of a...Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.展开更多
The novel complex [K(18-C-6)]_2 [Cd(mnt)_2] [18-C-6 = 18-crown-6, mnt =1,2-dicyanoethene-1,2-dithiolate, C_2S_2-(CN)_2^(2-)] was synthesized and characterized by elementalanalysis, IR spectrum and X-ray diffraction an...The novel complex [K(18-C-6)]_2 [Cd(mnt)_2] [18-C-6 = 18-crown-6, mnt =1,2-dicyanoethene-1,2-dithiolate, C_2S_2-(CN)_2^(2-)] was synthesized and characterized by elementalanalysis, IR spectrum and X-ray diffraction analysis. The complex displays two-dimensional networkstructure of [K(18-C-6)] complex segments and [Cd(mnt)_2] complex segment bridged by S-K-S, S-K-Nand N-K-N interactions between adjacent [K(18-C-6)] and [Cd(mnt)_2] units.展开更多
To avoid the aerodynamic performance loss of airfoil at non-design state which often appears in single point design optimization, and to improve the adaptability to the uncertain factors in actual flight environment, ...To avoid the aerodynamic performance loss of airfoil at non-design state which often appears in single point design optimization, and to improve the adaptability to the uncertain factors in actual flight environment, a two-dimensional stochastic airfoil optimization design method based on neural networks is presented. To provide highly efficient and credible analysis, four BP neural networks are built as surrogate models to predict the airfoil aerodynamic coefficients and geometry parameter. These networks are combined with the probability density function obeying normal distribution and the genetic algorithm, thus forming an optimization design method. Using the method, for GA（W）-2 airfoil, a stochastic optimization is implemented in a two-dimensional flight area about Mach number and angle of attack. Compared with original airfoil and single point optimization design airfoil, results show that the two-dimensional stochastic method can improve the performance in a specific flight area, and increase the airfoil adaptability to the stochastic changes of multiple flight parameters.展开更多
The copper(Ⅱ) complex [Cu_3(nta)_2(azpy)_2(H_2O)_2]·6H_2O (nta =nitrilotriacetate, azpy = 4,4′-azobispyridine) has been synthesized and characterized. The X-rayanalysis reveals that there are two kinds of copp...The copper(Ⅱ) complex [Cu_3(nta)_2(azpy)_2(H_2O)_2]·6H_2O (nta =nitrilotriacetate, azpy = 4,4′-azobispyridine) has been synthesized and characterized. The X-rayanalysis reveals that there are two kinds of copper(Ⅱ) coordination environments. Cu(1) has adistorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1) is linked toCu(2) through nta and bound to Cu(1C) by azpy, and Cu(2) is linked to Cu(2A) through azpy, whichextends to two-dimensional network with large rhombus 1.2 nm x 1.7 nm.展开更多
In an attempt to synthesize supra-molecular complex of copper(II) with mixed ligands in a solution reaction of Cu(ClO 4) 2·6H 2O with 4,5-diazafluorene-9-one (dafo) and o-phthalic acid, the bright blue col...In an attempt to synthesize supra-molecular complex of copper(II) with mixed ligands in a solution reaction of Cu(ClO 4) 2·6H 2O with 4,5-diazafluorene-9-one (dafo) and o-phthalic acid, the bright blue column-like crystal [Cu(dafo) 2(H 2O) 2]-(ClO 4) 2 was obtained. Its structure was determined by single-crystal X-ray diffraction study. The crystal belongs to monoclinic system, space group P2(1)/n with cell dimensions: a=0.7947(3) nm, b=1.2021(5) nm, c=1.3190(5) nm, α=90.000(5)°, β=90.000(5)°, γ= 90.000(5)°, V=1.2600(9) nm 3, Z=2, F(000)=670, M r=662.83, D c=1.747 g/cm 3, μ (Mo Kα)=1.154 mm -1, R 1=0.0455, wR 2=0.1041. The analysis of the crystal structure indicates that the complex has a two-dimensional network structure which is formed by hydrogen bonds.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
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
Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the ...Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this paper.First,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing process.Second,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR model.Finally,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation type.Theoretical analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR method.The recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR.展开更多
The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface...The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.展开更多
This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This m...This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.展开更多
In this study, an orthogonal array experiment is conducted by using a transparent fracture network replica. Image processing and theoretical analysis are performed to investigate the model sealing efficiency(SE), fact...In this study, an orthogonal array experiment is conducted by using a transparent fracture network replica. Image processing and theoretical analysis are performed to investigate the model sealing efficiency(SE), factors influencing SE, and the effect of flowing water on propagation. The results show that grout propagation can be classified into three patterns in the fracture network: sealing off, partial sealing,and major erosion. The factors controlling the SE in a descending order of the amount of influence are the initial water flow speed, fracture aperture, grout take, and gel time. An optimal value for the combination of the gel time and grout take(artificial factors) can result in a good SE. The grouting and seepage pressures are measured, and the results reveal that their variations can indicate the SE to some extent. The SE is good when the seepage pressure at each point increases overall;the frequent fluctuations in the seepage pressure indicate a moderately poor SE, and an overall decline in the seepage pressure indicates a major erosion type. The deflection effect of grouting shows an approximately elliptical propagation with the long axis expanding along the wider fracture opening, demonstrating further application in grouting design.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
A novel two-dimensional network manganese(Ⅱ) polymer complex [Mn(O2CCH2CI)2-(phen)]n has been synthesized and characterized by elemental analysis and IR spectrum. The crystal structure of title complex has also been ...A novel two-dimensional network manganese(Ⅱ) polymer complex [Mn(O2CCH2CI)2-(phen)]n has been synthesized and characterized by elemental analysis and IR spectrum. The crystal structure of title complex has also been determined, which is in monoclinic of a space group P21/c with the following unit cell parameters at 294K: a=1.9738(4) nm, b =1.1384(2) nm, c =0.74915(14) nm, V =1.6795(5) nm3, Z= 2.展开更多
Dissolved oxygen(DO)content is an important index of river water quality.Water quality sensors have been used in China for urban river water monitoring and DO content prediction.However,water quality sensors are expen...Dissolved oxygen(DO)content is an important index of river water quality.Water quality sensors have been used in China for urban river water monitoring and DO content prediction.However,water quality sensors are expensive and difficult to maintain,and have a short operation period and difficult to maintain.This study developed a scientific and accurate method for prediction of DO content changes using fish school features.The behavioral features of the Carassius auratus fish school were described using two-dimensional fish school images.The degree of DO content decline was graded into five levels,and the corresponding numerical ranges of cluster characteristic parameters were determined by considering the opinions of ichthyologists.Finally,the variation of DO content was predicted using the characteristic parameters of the fish school and the multiple-input single-output Takagi-Sugeno fuzzy neural network.The prediction results were basically consistent with the actual variations of DO content.Therefore,it is feasible to use the behavioral features of the fish school to dynamically predict the level of DO content in water,and this method is especially suitable for prediction of sharp decline of DO content in a relatively short time.展开更多
Mechanically cleaved two-dimensional materials are random in size and thickness.Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production.Deep learning algorithms have b...Mechanically cleaved two-dimensional materials are random in size and thickness.Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production.Deep learning algorithms have been adopted as an alternative,nevertheless a major challenge is a lack of sufficient actual training images.Here we report the generation of synthetic two-dimensional materials images using StyleGAN3 to complement the dataset.DeepLabv3Plus network is trained with the synthetic images which reduces overfitting and improves recognition accuracy to over 90%.A semi-supervisory technique for labeling images is introduced to reduce manual efforts.The sharper edges recognized by this method facilitate material stacking with precise edge alignment,which benefits exploring novel properties of layered-material devices that crucially depend on the interlayer twist-angle.This feasible and efficient method allows for the rapid and high-quality manufacturing of atomically thin materials and devices.展开更多
基金subsidised by the National Natural Science Founda-tion of China(No.32272380)the Key Research and Development Program of Shaanxi Province(No.2024NC-YBXM-140)Young Talent Fund of Association for Science and Technology in Shaanxi(No.20230225).
文摘As climacteric fruits,Mangoes are highly susceptible to spoilage and quality deterioration due to ethylene exposure.Protein-based nanofibers can potentially adsorb ethylene,but their stability in ethylene removal is often insufficient for practical applications.This study employs electrospinning to fabricate zein-based twodimensional network nanofiber films(T/N/Z films).The combination of zein and the two-dimensional network structure enhances ethylene adsorption efficiency through active functional groups and a high specific surface area.The addition of NaCl(N)and Tween 80(T)helps induce fiber splitting,reduce surface tension,and strengthen hydrogen bonding,imparting a network morphology to the material.The ethylene adsorption efficiency of the 0.7%T/N/Z films was 27.91±1.55 mg m^(-3)·h^(-1),significantly higher than that of the control group.Mango preservation experiments demonstrated that the 0.7%T/N/Z films reduced browning(2.70±2.42%)and increased fruit hardness(804.23±65.54 g)compared to all other treatments,extending the storage period by over 20 days.
基金supported by the National Natural Science Foundation of China(grant nos.22002044,21925201,22161160319,22201073,and 21978049)Shanghai Municipal Science and Technology Major Project,China(grant no.2018SHZDZX03)+2 种基金China Postdoctoral Science Foundation(grant nos.2022M711035 and 2021M702188)the Programme of Introducing Talents of Discipline to Universities,China(grant no.B16017)the Fundamental Research Funds for the Central Universities of China.We thank the Research Center of Analysis and Testing of East China University of Science and Technology for help with the characterization of our fabrications.
文摘Although electrostatic bonding between chalcogen(Ch)atoms(O,S,Se,and Te)and nitrogen(N)has emerged as a powerful driving force in the fabrication of supramolecular structures;this noncovalent bond has not yet been used to link polymers to form networks.In this study,we took advantage of additive enthalpy in forming multipoint noncovalent bonds to construct a two-dimensional(2D)network via the hierarchical on-surface synthesis of linear polymer chains,followed by multipoint S···N and S···H bonding.When 4,7-dibromobenzo[c][1,2,5]thiadiazole was used,only short oligomers with embedded bromine atoms and cross-linked byproducts were formed on Ag(111)or Au(111)surfaces after multiple annealing procedures,and no 2D network was observed.By changing the precursor to a similar iodinesubstituted molecule,long linear polymers were generated and assembled with iodine atoms on Au(111)after annealing at 523 K.After annealing at 603 K,iodine atoms were desorbed and polymer chains were assembled via multipoint noncovalent bonding.The 2D network remained intact after annealing at 653 K,demonstrating its high thermostability.The multipoint noncovalent bonds were investigated by the combination of scanning tunneling microscopy,noncontact atomic force microscopy,and density functional theory calculations,which revealed that S···N and S···H bonding were the driving forces to construct thermostable and orderly 2D networks.
基金supported by the NSFC(21731007,21890380,21821003 and 21701191)the Guangdong Pearl River Talents Program(2017BT01C161)the Fundamental Research Funds for the Central Universities(18lgpy42).
文摘Solvothermal reactions of 3-(3-methylpyridin-4-yl)benzoic acid (Hmpba) with Zn(Ⅱ),Cd(Ⅱ),or Cu(Ⅱ) salts yielded crystals of coordination polymers [Zn(mpba)_(2)] (1),[Cd(mpba)_(2)] (2),and [Cu(mpba)_(2)]·vip (3·g),respectively,possessing two-dimensional (2D) 4-connected sql coordination networks with different packing/interpenetration modes.1 and 2 both possess close-packing two-fold interpenetrated sql nets,but the ligand orientations in their single layers and the stacking manners of their double layers are quite different and have an inversed trend of complexity.The sql nets in 3 are non-interpenetrated,which loosely pack to give a porous structure with 1D channels.Interestingly,1–3 have a completely inversed trend in packing/interpenetration and porosity,compared to the coordination networks constructed by the same metal ions and the ligand without the methyl group (3-(pyridin-4-yl)benzoic acid).The porous framework of 3 can be retained after vip removal,as demonstrated by the CO_(2)adsorption isotherms and high catalytic performances for cycloaddition of epoxides and CO_(2).
文摘The two-dimensional grating serves as a critical component in plane grating interferometers for achieving high-precision multidimensional displacement measurements.The calibration of grating groove density and orthogonality error of grating grooves not only improves the positioning accuracy of grating interferometers but also provides essential feedback for optimizing two-dimensional grating fabrication.This study proposes a method for simultaneous calibration of these parameters using orthogonal heterodyne laser interferometry.A two-dimensional grating interferometer is built with the grating to be measured,and a biaxial laser interferometer provides a displacement reference for it.The phase mapping relationship between grating interference and laser interference is established.The interference phase information obtained by any two displacements can simultaneously solve the above three parameters and obtain the grating installation error.The feasibility of the proposed method is verified by using a 1200 gr/mm two-dimensional grating.The standard deviation of the grating groove density in the X and Y directions is 0.012 gr/mm and 0.014 gr/mm,respectively.The standard deviation of the orthogonality error of grating grooves is 0.004°,and the standard deviation of the installation error is 0.002°.Compared with the atomic force microscope method,the consistency of the grating groove density in the X and Y directions is better than 0.03 gr/mm and 0.06 gr/mm,and the orthogonality error of grating grooves is better than 0.008°.The experimental results show that the proposed method can be simply and efficiently applied to the calibration of the grating line parameters of the two-dimensional grating.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051,ZR2025QB50)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2025A1515011191)the Shanghai Sailing Program(23YF1402200,23YF1402400)funded by Basic Research Program of Jiangsu(BK20240424)Open Research Fund of State Key Laboratory of Crystal Materials(KF2406)Taishan Scholar Foundation of Shandong Province(tsqn202408006,tsqn202507058)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University。
文摘As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.
基金supported by the Fundamental Research Funds for the Central Universities(WUT:2024IVA052 and Grant No.104972025KFYjc0089)。
文摘Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.
文摘The novel complex [K(18-C-6)]_2 [Cd(mnt)_2] [18-C-6 = 18-crown-6, mnt =1,2-dicyanoethene-1,2-dithiolate, C_2S_2-(CN)_2^(2-)] was synthesized and characterized by elementalanalysis, IR spectrum and X-ray diffraction analysis. The complex displays two-dimensional networkstructure of [K(18-C-6)] complex segments and [Cd(mnt)_2] complex segment bridged by S-K-S, S-K-Nand N-K-N interactions between adjacent [K(18-C-6)] and [Cd(mnt)_2] units.
文摘To avoid the aerodynamic performance loss of airfoil at non-design state which often appears in single point design optimization, and to improve the adaptability to the uncertain factors in actual flight environment, a two-dimensional stochastic airfoil optimization design method based on neural networks is presented. To provide highly efficient and credible analysis, four BP neural networks are built as surrogate models to predict the airfoil aerodynamic coefficients and geometry parameter. These networks are combined with the probability density function obeying normal distribution and the genetic algorithm, thus forming an optimization design method. Using the method, for GA（W）-2 airfoil, a stochastic optimization is implemented in a two-dimensional flight area about Mach number and angle of attack. Compared with original airfoil and single point optimization design airfoil, results show that the two-dimensional stochastic method can improve the performance in a specific flight area, and increase the airfoil adaptability to the stochastic changes of multiple flight parameters.
文摘The copper(Ⅱ) complex [Cu_3(nta)_2(azpy)_2(H_2O)_2]·6H_2O (nta =nitrilotriacetate, azpy = 4,4′-azobispyridine) has been synthesized and characterized. The X-rayanalysis reveals that there are two kinds of copper(Ⅱ) coordination environments. Cu(1) has adistorted square plane symmetry and Cu(2) has a distorted octahedral symmetry. Cu(1) is linked toCu(2) through nta and bound to Cu(1C) by azpy, and Cu(2) is linked to Cu(2A) through azpy, whichextends to two-dimensional network with large rhombus 1.2 nm x 1.7 nm.
文摘In an attempt to synthesize supra-molecular complex of copper(II) with mixed ligands in a solution reaction of Cu(ClO 4) 2·6H 2O with 4,5-diazafluorene-9-one (dafo) and o-phthalic acid, the bright blue column-like crystal [Cu(dafo) 2(H 2O) 2]-(ClO 4) 2 was obtained. Its structure was determined by single-crystal X-ray diffraction study. The crystal belongs to monoclinic system, space group P2(1)/n with cell dimensions: a=0.7947(3) nm, b=1.2021(5) nm, c=1.3190(5) nm, α=90.000(5)°, β=90.000(5)°, γ= 90.000(5)°, V=1.2600(9) nm 3, Z=2, F(000)=670, M r=662.83, D c=1.747 g/cm 3, μ (Mo Kα)=1.154 mm -1, R 1=0.0455, wR 2=0.1041. The analysis of the crystal structure indicates that the complex has a two-dimensional network structure which is formed by hydrogen bonds.
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National Natural Science Foundation of China under Grant No.61973037China Postdoctoral Science Foundation under Grant No.2022M720419。
文摘Automatic modulation recognition(AMR)of radiation source signals is a research focus in the field of cognitive radio.However,the AMR of radiation source signals at low SNRs still faces a great challenge.Therefore,the AMR method of radiation source signals based on two-dimensional data matrix and improved residual neural network is proposed in this paper.First,the time series of the radiation source signals are reconstructed into two-dimensional data matrix,which greatly simplifies the signal preprocessing process.Second,the depthwise convolution and large-size convolutional kernels based residual neural network(DLRNet)is proposed to improve the feature extraction capability of the AMR model.Finally,the model performs feature extraction and classification on the two-dimensional data matrix to obtain the recognition vector that represents the signal modulation type.Theoretical analysis and simulation results show that the AMR method based on two-dimensional data matrix and improved residual network can significantly improve the accuracy of the AMR method.The recognition accuracy of the proposed method maintains a high level greater than 90% even at -14 dB SNR.
基金supported by the National Nat-ural Science Foundation of China(Nos.62174122,U2241244,and 52302046)Major Program(JD)of Hubei Province(No.2023BAA008)+2 种基金the Fundamental Research Funds for the Central Universities(Nos.2042023kf0116 and 2042023kf1041)the Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011764 and 2024A1515010383)the Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(No.EMPI2023016).
文摘The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.
基金supported by the Shihezi University High-Level Talents Research Startup Project(Project No.RCZK202521)the National Natural Science Foundation of China(Grant Nos.12271066,11871121,12171405)+1 种基金the Chongqing Natural Science Foundation Joint Fund for Innovation and Development Project(Project No.CSTB2024NSCQLZX0085)the Chongqing Normal University Foundation(Grant No.23XLB018).
文摘This paper investigates ruin,capital injection,and dividends for a two-dimensional risk model.The model posits that surplus levels of insurance companies are governed by a perturbed composite Poisson risk model.This model introduces a dependence between the two surplus levels,present in both the associated perturbations and the claims resulting from common shocks.Critical levels of capital injection and dividends are established for each of the two risks.The surplus levels are observed discretely at fixed intervals,guiding decisions on capital injection,dividends,and ruin at these junctures.This study employs a two-dimensional Fourier cosine series expansion method to approximate the finite time expected discounted operating cost until ruin.The ensuing approximation error is also quantified.The validity and accuracy of the method are corroborated through numerical examples.Furthermore,the research delves into the optimal capital allocation problem.
基金supported by the Natural Science Foundation of China under (Nos. 42172293, 4190020747, and 41472268)。
文摘In this study, an orthogonal array experiment is conducted by using a transparent fracture network replica. Image processing and theoretical analysis are performed to investigate the model sealing efficiency(SE), factors influencing SE, and the effect of flowing water on propagation. The results show that grout propagation can be classified into three patterns in the fracture network: sealing off, partial sealing,and major erosion. The factors controlling the SE in a descending order of the amount of influence are the initial water flow speed, fracture aperture, grout take, and gel time. An optimal value for the combination of the gel time and grout take(artificial factors) can result in a good SE. The grouting and seepage pressures are measured, and the results reveal that their variations can indicate the SE to some extent. The SE is good when the seepage pressure at each point increases overall;the frequent fluctuations in the seepage pressure indicate a moderately poor SE, and an overall decline in the seepage pressure indicates a major erosion type. The deflection effect of grouting shows an approximately elliptical propagation with the long axis expanding along the wider fracture opening, demonstrating further application in grouting design.
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.
基金supported by the National Natural Science Foundation of China(Grant No.20271041)Shaanxi Province Natural Science Foundation(Grant No.2002B04).
文摘A novel two-dimensional network manganese(Ⅱ) polymer complex [Mn(O2CCH2CI)2-(phen)]n has been synthesized and characterized by elemental analysis and IR spectrum. The crystal structure of title complex has also been determined, which is in monoclinic of a space group P21/c with the following unit cell parameters at 294K: a=1.9738(4) nm, b =1.1384(2) nm, c =0.74915(14) nm, V =1.6795(5) nm3, Z= 2.
基金supported by the Natural Science Foundation of Changzhou City,China(Grants No.CE20195026 and CE20205031)the Teaching Steering Committee of Electronics Information Specialty in Colleges and Universities of the Ministry of Education(Grant No.2020-YB-42)the Jiangsu Overseas Visiting Scholar Program for University Prominent Young and Middle Aged Teachers and Presidents.
文摘Dissolved oxygen(DO)content is an important index of river water quality.Water quality sensors have been used in China for urban river water monitoring and DO content prediction.However,water quality sensors are expensive and difficult to maintain,and have a short operation period and difficult to maintain.This study developed a scientific and accurate method for prediction of DO content changes using fish school features.The behavioral features of the Carassius auratus fish school were described using two-dimensional fish school images.The degree of DO content decline was graded into five levels,and the corresponding numerical ranges of cluster characteristic parameters were determined by considering the opinions of ichthyologists.Finally,the variation of DO content was predicted using the characteristic parameters of the fish school and the multiple-input single-output Takagi-Sugeno fuzzy neural network.The prediction results were basically consistent with the actual variations of DO content.Therefore,it is feasible to use the behavioral features of the fish school to dynamically predict the level of DO content in water,and this method is especially suitable for prediction of sharp decline of DO content in a relatively short time.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFB2803900)the National Natural Science Foundation of China(Grant Nos.61974075 and 61704121)+2 种基金the Natural Science Foundation of Tianjin Municipality(Grant Nos.22JCZDJC00460 and 19JCQNJC00700)Tianjin Municipal Education Commission(Grant No.2019KJ028)Fundamental Research Funds for the Central Universities(Grant No.22JCZDJC00460).
文摘Mechanically cleaved two-dimensional materials are random in size and thickness.Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production.Deep learning algorithms have been adopted as an alternative,nevertheless a major challenge is a lack of sufficient actual training images.Here we report the generation of synthetic two-dimensional materials images using StyleGAN3 to complement the dataset.DeepLabv3Plus network is trained with the synthetic images which reduces overfitting and improves recognition accuracy to over 90%.A semi-supervisory technique for labeling images is introduced to reduce manual efforts.The sharper edges recognized by this method facilitate material stacking with precise edge alignment,which benefits exploring novel properties of layered-material devices that crucially depend on the interlayer twist-angle.This feasible and efficient method allows for the rapid and high-quality manufacturing of atomically thin materials and devices.
