The attention mechanism can extract salient features in images,which has been proved to be effective in improving the performance of person re-identification(Re-ID).However,most of the existing attention modules have ...The attention mechanism can extract salient features in images,which has been proved to be effective in improving the performance of person re-identification(Re-ID).However,most of the existing attention modules have the following two shortcomings:On the one hand,they mostly use global average pooling to generate context descriptors,without highlighting the guiding role of salient information on descriptor generation,resulting in insufficient ability of the final generated attention mask representation;On the other hand,the design of most attention modules is complicated,which greatly increases the computational cost of the model.To solve these problems,this paper proposes an attention module called self-supervised recalibration(SR)block,which introduces both global and local information through adaptive weighted fusion to generate a more refined attention mask.In particular,a special"Squeeze-Excitation"(SE)unit is designed in the SR block to further process the generated intermediate masks,both for nonlinearizations of the features and for constraint of the resulting computation by controlling the number of channels.Furthermore,we combine the most commonly used Res Net-50 to construct the instantiation model of the SR block,and verify its effectiveness on multiple Re-ID datasets,especially the mean Average Precision(m AP)on the Occluded-Duke dataset exceeds the state-of-the-art(SOTA)algorithm by 4.49%.展开更多
For projects near the tectonic belt,mylonite of varying metamorphic degrees may be present.The matrix proportion of rock reflects its internal microscopic characteristics,thus it is beneficial for engineering geology ...For projects near the tectonic belt,mylonite of varying metamorphic degrees may be present.The matrix proportion of rock reflects its internal microscopic characteristics,thus it is beneficial for engineering geology to study the effect of the matrix proportion on the mechanical properties and rupture behaviors of rock.Samples of mylonitic granite and granitic protomylonite with varying matrix proportions were obtained from a ductile shear zone for a series of uniaxial compression and acoustic emission(AE)tests.The results showed that with the increase in matrix proportion,the average strength and elastic modulus of the samples increased,and the rock sample with the largest matrix proportion exhibited the maximum peak stress of 244.42 MPa,which was 45.86%greater than the average peak stress of the rock samples with the smallest matrix proportions.For the rock samples with larger matrix proportion,their mechanical parameters exhibited greater dispersion and the large-scale appearance of AE events occurred earlier,showing a relatively gradual failure process.These samples had larger accumulated AE parameter values and greater degree of failure.In contrast,for samples with smaller matrix proportions,the large-scale appearance of AE events occurred close to the peak stress,indicating that the occurrence of damage and fractures was centralized and instantaneous.These samples had lower accumulated AE parameter values and fewer cracks after failure.Additionally,for the rock samples with more matrix proportion,the average variance of the b-value was 1.1,which was lower than that of rock samples with the smallest matrix proportion(the average variance of the b-value was 3.7).Furthermore,it can be predicted that under certain stress,the failure depth around a tunnel is generally smaller when the strength of rock samples with larger matrix proportion is greater.展开更多
[Objective] This study presents a method for mass rearing of Aphidius gifuensis, a dominant endoparasitoid of Myzus persicae on tobacco in Southwest China. [Method] The tobacco cultivar Honghuadajinyuan(Nicotiana taba...[Objective] This study presents a method for mass rearing of Aphidius gifuensis, a dominant endoparasitoid of Myzus persicae on tobacco in Southwest China. [Method] The tobacco cultivar Honghuadajinyuan(Nicotiana tabacum) was used as the host plant and M. persicae was the host insect. In a greenhouse, tobacco seedlings were reared in plastic trays. The seedlings at three-true-leaf stage were inoculated with two to three aphids per plant using aphid source with a parasitism rate of 47% ±3.9%. [Result] By this inoculation method, the aphids and parasites were simultaneously inoculated on host plants. After approximately 25 d of rearing, we were able to produce 82.5±5.17 aphid mummies per tobacco seedling. A total of 445 500 aphid mummies were produced in one greenhouse(36 rearing trays per greenhouse) during an approximately 50-day rearing period. The emergence rate was 93.4% ±2.76%, and 54% of the mummies were females. [Conclusion] The demonstrated technological feasibility of using tobacco seedlings for the mass rearing of A. gifuensis increases the potential for the biological control of M. persicae.展开更多
The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we develop...The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors(NASICON)Na_(1.3+x)Al_(0.3)Ce_(x)Ti_(1.7-x)(PO_(4))_(3)(NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide(LiTFSI) matrix.A strong interaction between Ce^(3+)from NCATP and TFSI-anion from the polymer matrix contributes to the fast Li+transportation at the interface.The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 × 0^(-3) S cm^(-1) and a Li^(+) transference number of 0.88.A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm^(-2) presents outstanding cycling stability over 2000 h at 25℃.The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO_(4) at 2 C after 400 cycles and Li/CPEs/LiCoO_(2) at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g^(-1) at 25℃,respectively.展开更多
Supercapacitors have been regarded as promising power supplies for future electronics due to their high power density,superior stability,easy integration,and safety.Extrusion-based three-dimensional printing technolog...Supercapacitors have been regarded as promising power supplies for future electronics due to their high power density,superior stability,easy integration,and safety.Extrusion-based three-dimensional printing technologies hold promise to satisfy the demands for integrated and flexible supercapacitors because of their highly versatile manufacturing process.In this review article,a comprehensive and timely review of these state-of-theart technologies is presented.We start with a brief introduction of fundamental concepts of supercapacitors,including energy storage mechanisms and device structures.Then,the latest progress of extrusionbased three-dimensional printing technologies(e.g.,fused deposition modeling,inkjet printing,and direct ink writing)along with their applications for manufacturing supercapacitors is summarized.The choice of printable materials(e.g.,graphene,carbon nanotubes,metal oxides,and MXenes),printing process,and the resulted electrochemical performances of supercapacitors are especially emphasized.Finally,the development of extrusion-based three-dimensional printing supercapacitors is summarized,with existing challenges diagnosed,possible solutions proposed,and future outlooks forecasted.We hope this review can offer insights to further improve the performance of three-dimensional-printed supercapacitors for practical applications.展开更多
Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap e...Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap energy varies from 0.7 eV to 6.2 eV, which shows great potential for application in photodetectors. Here, we report the fabrication and performance evaluation of integrated Al_(1-x)In_(x)N on a free-standing GaN substrate through direct radio-frequency magnetron sputtering.The optical properties of Al_(1-x)In_(x)N will be enhanced by the polarization effect of a heterostructure composed of Al_(1-x)In_(x)N and other Ⅲ-nitride materials. An Al_(1-x)In_(x)N/Ga N visible-light photodetector was prepared by semiconductor fabrication technologies such as lithography and metal deposition. The highest photoresponsivity achieved was 1.52 A·W^(-1)under 365 nm wavelength illumination and the photodetector was determined to have the composition Al0.75In0.25N/GaN.A rise time of 0.55 s was observed after transient analysis of the device. The prepared Al_(1-x)In_(x)N visible-light photodetector had a low dark current, high photoresponsivity and fast response speed. By promoting a low-cost, simple fabrication method,this study expands the application of ternary alloy Al_(1-x)In_(x)N visible-light photodetectors in optical communication.展开更多
Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with thr...Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.展开更多
Visual Place Recognition(VPR)technology aims to use visual information to judge the location of agents,which plays an irreplaceable role in tasks such as loop closure detection and relocation.It is well known that pre...Visual Place Recognition(VPR)technology aims to use visual information to judge the location of agents,which plays an irreplaceable role in tasks such as loop closure detection and relocation.It is well known that previous VPR algorithms emphasize the extraction and integration of general image features,while ignoring the mining of salient features that play a key role in the discrimination of VPR tasks.To this end,this paper proposes a Domain-invariant Information Extraction and Optimization Network(DIEONet)for VPR.The core of the algorithm is a newly designed Domain-invariant Information Mining Module(DIMM)and a Multi-sample Joint Triplet Loss(MJT Loss).Specifically,DIMM incorporates the interdependence between different spatial regions of the feature map in the cascaded convolutional unit group,which enhances the model’s attention to the domain-invariant static object class.MJT Loss introduces the“joint processing of multiple samples”mechanism into the original triplet loss,and adds a new distance constraint term for“positive and negative”samples,so that the model can avoid falling into local optimum during training.We demonstrate the effectiveness of our algorithm by conducting extensive experiments on several authoritative benchmarks.In particular,the proposed method achieves the best performance on the TokyoTM dataset with a Recall@1 metric of 92.89%.展开更多
In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulati...In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulation model and numerical simulation were established using the discrete element software EDEM.Then a second-order response model between contact parameters and repose angle had been constructed.The test result showed that the static friction coefficient,rolling friction coefficient,and coefficient of restitution between cotton stems were crucial factors affecting the repose angle.The determination coefficient corrected determination coefficient and p-value of the second-order response model were R^(2)=0.959,R^(2)_(adj)=0.921,and p<0.0001 respectively.The error values of the comparison between the simulation test results and the corresponding physical test values were all less than 10%,which showed that the model was reliable and had high interpretation and predictability,this study can provide a certain theoretical basis and data support for the setting of contact parameters in the data simulation of cotton stem harvesting and processing,mechanically-harvested film residue crushing and film stem separation,etc.展开更多
The electrosynthesis of hydrogen peroxide(H2O2)from oxygen reduction reaction(ORR)via a two-electron pathway provides an appealing alternative to the energy-intensive anthraquinone route;however,the development of ORR...The electrosynthesis of hydrogen peroxide(H2O2)from oxygen reduction reaction(ORR)via a two-electron pathway provides an appealing alternative to the energy-intensive anthraquinone route;however,the development of ORR with high selectivity and durability for H2O2 production is still challenging.Herein,we demonstrate an active and stable catalyst,composing of highly dispersed Ag nanoclusters on N-doped hollow carbon spheres(NC-Ag/NHCS),which can effectively reduce O2 molecules into H2O2 with a selectivity of 89%–91%in a potential range from 0.2 to 0.7 V(vs.reversible hydrogen electrode(RHE))in acidic media.Strikingly,NC-Ag/NHCS achieve a mass activity of 27.1 A·g^(−1) and a yield rate of 408 mmol·gcat.^(−1)·h^(−1) at 0.7 V,both of which are comparable with the best-reported results.Furthermore,NC-Ag/NHCS enable catalyzing H2O2 production with a stable current density over 48-h electrolysis and only about 9.8%loss in selectivity after 10,000 cycles.Theoretical analyses indicate that Ag nanoclusters can contribute more electrons to favor the protonation of adsorbed O2,thus leading to a high H2O2 selectivity.This work confirms the great potential of metal nanocluster-based materials for H2O2 electrosynthesis under ambient conditions.展开更多
The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiolo...The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring,but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological function.However,most bioelectronic devices built on planar polymeric substrates,such as polydimethylsiloxane(PDMS),polyurethane(PU),and polyimide(PI),lack efficient gas permeability,which may hinder the emission of volatile compounds from the surface of living organism,affecting the natural metabolism and reducing the comfort of wearing.Thus,achieving permeability or breathability in bioelectronic devices is a significant challenge.Currently,the devices made of gas-permeable materials with porous structures,that combine electronic components with daily garments,such as fibric and textile,offer exciting opportunities for breathable electronics.In this review,several types of gas-permeable materials with their synthesis and processing routes are outlines.Then,two methods for measuring water vapor transmission rate of materials are discussed in depth.Finally,recent progress in the use of gaspermeable materials for the applications of plant-and skin-attached electronics is summarized systematically.展开更多
In-depth understandings of charge carrier transfer dynamics in any artificial catalytic system are of critical importance for the future design of highly efficient photocatalysts.Herein,we synthesized sub-monolayer Zn...In-depth understandings of charge carrier transfer dynamics in any artificial catalytic system are of critical importance for the future design of highly efficient photocatalysts.Herein,we synthesized sub-monolayer ZnSe partial-shell coated CdSe/CdS core/shell quantum dots in a controlled fashion.The ZnSe decorated quantum dots were employed as a model catalyst for photogeneration of H_(2)under light illumination.Both theoretical calculations and experimental results unravel that the growth of ZnSe partial-shell would retard the photogenerated electron transfer,and meanwhile,accelerate the corresponding hole migration process during the H_(2)photogeneration reaction in the artificial photocatalytic system.As such,the performance of the relevant photocatalytic system can be modulated and optimized,and accordingly,a plausible underlying mechanism is rationalized.展开更多
Searching for insensitive melt-castable energetic materials is still facing great challenges.In this work,we developed a promising strategy that is regulating the ratio of non-covalent interaction by fluorine atoms to...Searching for insensitive melt-castable energetic materials is still facing great challenges.In this work,we developed a promising strategy that is regulating the ratio of non-covalent interaction by fluorine atoms to regulate the melting point to develop new melt-castable energetic materials.Using this method,a highly sym-metric 1,2-difluoro-4,5-dinitrobenzene(DFDNB)was synthesized in one step and fully characterized.DFDNB has a desirable melting point(83.2℃),high decomposition temperature(>400℃),acceptable detonation properties(6786 m s^(-1),21.5 GPa)but superior safety performance(>40 J,>360 N),and excellent chemical compatibility with 1,3,5-trinitro-1,3,5-triazine(RDX)that make it a promising insensitive melt-castable energetic material.A detailed study based on crystal stacking,electrostatic potential,and intermolecular weak interactions in DFDNB and its isomers or analogs demonstrates that non-covalent interactions including the C-F…H,N-O…H hydrogen bonding,and C-F…O halogen-like bonding play an important role in regulating the melting point.展开更多
Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat...Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat(PQ),a toxic herbicide,in aqueous environments.A linear experiment performed using square wave voltammetry(SWV)under optimized experimental conditions produced a decent linear relationship and a low detection limit(LOD)of 2.74 nmol/L(S/N=3).Repeatability,reproducibility,stability,and interference experiments confirmed that the Fe_(2)O_(3)–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules.Notably,the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples.To the best of our knowledge,this is the first study on the preparation of Fe_(2)O_(3)–BCN nanosheets for PQ detection.The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.展开更多
As the existing residual film crushing device in Xinjiang cannot directly crush membrane-impurity mixed material,by analyzing the compressive and cutting force characteristics of residual film material layer and cotto...As the existing residual film crushing device in Xinjiang cannot directly crush membrane-impurity mixed material,by analyzing the compressive and cutting force characteristics of residual film material layer and cotton stalk,the cutting conditions of mixed materials were obtained,and the method of cutting was determined.A multi-edge toothed cutters was created,and a cutting device was built.It was preliminarily determined that the number of teeth in the cutters was 8,the clearance between the teeth and between the tooth and fixed blade was 3 mm,the speed of the high-speed cutter was 800 r/min,and the speed difference between the high-and low-speed cutters was-300 r/min.Test results show that the ratio of residual film to total residual film sampling mass was(2.22±0.30)%,(19.19±2.02)%,(58.94±3.19)% and(20.65±2.05)%,respectively,when the maximum outer profile size in the range of[0,20)mm,[20,100)mm,[100,500)mm and[500,~)mm.The mass of cotton stalks with lengths of[0,50)mm,[50,100)mm and[100,~)mm accounted for(32.57±1.5)%,(27.77±1.3)%and(39.66±1.75)%,respectively,and the cutting power consumption was(85.41±15.63)kJ.The test results can provide a basis for the subsequent membrane-impurity mixed material cutting technology,as well as some guidance for the separation of it.展开更多
The restitution coefficient(RC)of cotton stalks is an important elementary physical parameter that is required to establish the crushing mechanical model and research the film residue separation machinery.In this stud...The restitution coefficient(RC)of cotton stalks is an important elementary physical parameter that is required to establish the crushing mechanical model and research the film residue separation machinery.In this study,the calculation method of restitution coefficient considering the rotation motion of stalk-shaped agricultural materials was derived based on the principle of kinematics and the energy restitution coefficient method,and a test bench for measuring the RC was designed and built.The effects of collision material,moisture content,length,diameter,release height,and collision angle respectively on the RC were investigated by single-factor experiments and orthogonal experiments,and the regression models between influence factors and the RC were established.The results showed that Q235 showed the highest value of the RC,and it was followed by cotton stalks and soil lumps,sequentially.The RC of cotton stalks decreased with the increase of moisture content and diameter,while it increased at first and then decreased with the increase of length.As the release height was less than 500 mm,the RC increased with the increased release height.As the collision angle was less than 40°,the RC showed a linear increasing trend.The significance of the effects of factors on RC decreased with the following sequence:collision angle,length,release height,diameter,and moisture content.Length,collision angle,and release height were extremely significant.The contrast test results showed that the values based on Newton’s restitution coefficient method were smaller than that based on the energy restitution coefficient method.The verification test showed that the predicted rebound height of cotton stalks calculated based on the energy restitution coefficient method was closer to the actual rebound height,and the relative error was less than 5%.展开更多
基金supported in part by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2022D01B186 and No.2022D01B05)。
文摘The attention mechanism can extract salient features in images,which has been proved to be effective in improving the performance of person re-identification(Re-ID).However,most of the existing attention modules have the following two shortcomings:On the one hand,they mostly use global average pooling to generate context descriptors,without highlighting the guiding role of salient information on descriptor generation,resulting in insufficient ability of the final generated attention mask representation;On the other hand,the design of most attention modules is complicated,which greatly increases the computational cost of the model.To solve these problems,this paper proposes an attention module called self-supervised recalibration(SR)block,which introduces both global and local information through adaptive weighted fusion to generate a more refined attention mask.In particular,a special"Squeeze-Excitation"(SE)unit is designed in the SR block to further process the generated intermediate masks,both for nonlinearizations of the features and for constraint of the resulting computation by controlling the number of channels.Furthermore,we combine the most commonly used Res Net-50 to construct the instantiation model of the SR block,and verify its effectiveness on multiple Re-ID datasets,especially the mean Average Precision(m AP)on the Occluded-Duke dataset exceeds the state-of-the-art(SOTA)algorithm by 4.49%.
基金supported by the National Natural Science Foundation of China(Grant No.52125402)the Natural Science Foundation of Sichuan Province,China(Grant No.2022NSFSC0005).
文摘For projects near the tectonic belt,mylonite of varying metamorphic degrees may be present.The matrix proportion of rock reflects its internal microscopic characteristics,thus it is beneficial for engineering geology to study the effect of the matrix proportion on the mechanical properties and rupture behaviors of rock.Samples of mylonitic granite and granitic protomylonite with varying matrix proportions were obtained from a ductile shear zone for a series of uniaxial compression and acoustic emission(AE)tests.The results showed that with the increase in matrix proportion,the average strength and elastic modulus of the samples increased,and the rock sample with the largest matrix proportion exhibited the maximum peak stress of 244.42 MPa,which was 45.86%greater than the average peak stress of the rock samples with the smallest matrix proportions.For the rock samples with larger matrix proportion,their mechanical parameters exhibited greater dispersion and the large-scale appearance of AE events occurred earlier,showing a relatively gradual failure process.These samples had larger accumulated AE parameter values and greater degree of failure.In contrast,for samples with smaller matrix proportions,the large-scale appearance of AE events occurred close to the peak stress,indicating that the occurrence of damage and fractures was centralized and instantaneous.These samples had lower accumulated AE parameter values and fewer cracks after failure.Additionally,for the rock samples with more matrix proportion,the average variance of the b-value was 1.1,which was lower than that of rock samples with the smallest matrix proportion(the average variance of the b-value was 3.7).Furthermore,it can be predicted that under certain stress,the failure depth around a tunnel is generally smaller when the strength of rock samples with larger matrix proportion is greater.
基金Supported by Yunnan Provincial Tobacco Corporation(09YN015,2012YN14)
文摘[Objective] This study presents a method for mass rearing of Aphidius gifuensis, a dominant endoparasitoid of Myzus persicae on tobacco in Southwest China. [Method] The tobacco cultivar Honghuadajinyuan(Nicotiana tabacum) was used as the host plant and M. persicae was the host insect. In a greenhouse, tobacco seedlings were reared in plastic trays. The seedlings at three-true-leaf stage were inoculated with two to three aphids per plant using aphid source with a parasitism rate of 47% ±3.9%. [Result] By this inoculation method, the aphids and parasites were simultaneously inoculated on host plants. After approximately 25 d of rearing, we were able to produce 82.5±5.17 aphid mummies per tobacco seedling. A total of 445 500 aphid mummies were produced in one greenhouse(36 rearing trays per greenhouse) during an approximately 50-day rearing period. The emergence rate was 93.4% ±2.76%, and 54% of the mummies were females. [Conclusion] The demonstrated technological feasibility of using tobacco seedlings for the mass rearing of A. gifuensis increases the potential for the biological control of M. persicae.
基金the National Key Research and Development Program of China (No. 2020YFC1909604)the Shenzhen Key Projects of Technological Research (JSGG2020092514 5800001)。
文摘The isolated inorganic particles within composite polymer electrolytes(CPEs) are not correlated to the Li^(+)transfer network,resulting in the polymer dominating the low ionic conductivity of CPEs.Therefore,we developed novel quasi-solid-state CPEs of a Ce-doped Na super ion conductors(NASICON)Na_(1.3+x)Al_(0.3)Ce_(x)Ti_(1.7-x)(PO_(4))_(3)(NCATP) chemically coupled poly(vinylidene fluoride-hexafluoropropylene)(PVDF-HFP)/Li-bis(trifluoromethanes-ulfonyl)imide(LiTFSI) matrix.A strong interaction between Ce^(3+)from NCATP and TFSI-anion from the polymer matrix contributes to the fast Li+transportation at the interface.The PVDF-HFP/NCATP CPEs exhibit an ionic conductivity of 2.16 × 0^(-3) S cm^(-1) and a Li^(+) transference number of 0.88.A symmetric Li/Li cell with NCATP-integrated CPEs at 0.1 mA cm^(-2) presents outstanding cycling stability over 2000 h at 25℃.The quasi-solid-state Li metal batteries of Li/CPEs/LiFePO_(4) at 2 C after 400 cycles and Li/CPEs/LiCoO_(2) at 0.2 C after 120 cycles deliver capacities of 100 and 152 mAh g^(-1) at 25℃,respectively.
基金supported by the National Natural Science Foundation of China(No.21905202)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016)+4 种基金Key Laboratory of Third-Generation Semiconductor Materials and Devices,Longgang District(PT2020D003)Guangdong Third-Generation Semiconductor Engineering Technology Development Center(2020GCZX007)the Australian Research Council under the Discovery Project(No.DP200100365)SZIIT Grant(SZIIT2021KJ020 and SZIIT2020KJ006)the Discovery Early Career Researcher Award(DECRA,No.DE170100871)。
文摘Supercapacitors have been regarded as promising power supplies for future electronics due to their high power density,superior stability,easy integration,and safety.Extrusion-based three-dimensional printing technologies hold promise to satisfy the demands for integrated and flexible supercapacitors because of their highly versatile manufacturing process.In this review article,a comprehensive and timely review of these state-of-theart technologies is presented.We start with a brief introduction of fundamental concepts of supercapacitors,including energy storage mechanisms and device structures.Then,the latest progress of extrusionbased three-dimensional printing technologies(e.g.,fused deposition modeling,inkjet printing,and direct ink writing)along with their applications for manufacturing supercapacitors is summarized.The choice of printable materials(e.g.,graphene,carbon nanotubes,metal oxides,and MXenes),printing process,and the resulted electrochemical performances of supercapacitors are especially emphasized.Finally,the development of extrusion-based three-dimensional printing supercapacitors is summarized,with existing challenges diagnosed,possible solutions proposed,and future outlooks forecasted.We hope this review can offer insights to further improve the performance of three-dimensional-printed supercapacitors for practical applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61974144, 62004127, and 12074263)Key-Area Research and Development Program of Guangdong Province (Grant Nos. 2020B010174003 and 2020B010169001)+2 种基金Guangdong Science Foundation for Distinguished Young Scholars (Grant No. 2022B1515020073)the Science and Technology Foundation of Shenzhen (Grant No. JSGG20191129114216474)the Open Project of State Key Laboratory of Functional Materials for Informatics。
文摘Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap energy varies from 0.7 eV to 6.2 eV, which shows great potential for application in photodetectors. Here, we report the fabrication and performance evaluation of integrated Al_(1-x)In_(x)N on a free-standing GaN substrate through direct radio-frequency magnetron sputtering.The optical properties of Al_(1-x)In_(x)N will be enhanced by the polarization effect of a heterostructure composed of Al_(1-x)In_(x)N and other Ⅲ-nitride materials. An Al_(1-x)In_(x)N/Ga N visible-light photodetector was prepared by semiconductor fabrication technologies such as lithography and metal deposition. The highest photoresponsivity achieved was 1.52 A·W^(-1)under 365 nm wavelength illumination and the photodetector was determined to have the composition Al0.75In0.25N/GaN.A rise time of 0.55 s was observed after transient analysis of the device. The prepared Al_(1-x)In_(x)N visible-light photodetector had a low dark current, high photoresponsivity and fast response speed. By promoting a low-cost, simple fabrication method,this study expands the application of ternary alloy Al_(1-x)In_(x)N visible-light photodetectors in optical communication.
基金Project supported by the National Natural Science Foundation of China(Grant No.61774172)the Guangdong Provincial Department of Science and Technology,China(Grant Nos.2019B010132002 and 2016B090918106)+1 种基金the Pengcheng Scholar Funding(2018)Shenzhen Science and Technology Innovation Committee,China(Grant No.KQJSCX20180323174713505).
文摘Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region under grant number 2022D01B186.
文摘Visual Place Recognition(VPR)technology aims to use visual information to judge the location of agents,which plays an irreplaceable role in tasks such as loop closure detection and relocation.It is well known that previous VPR algorithms emphasize the extraction and integration of general image features,while ignoring the mining of salient features that play a key role in the discrimination of VPR tasks.To this end,this paper proposes a Domain-invariant Information Extraction and Optimization Network(DIEONet)for VPR.The core of the algorithm is a newly designed Domain-invariant Information Mining Module(DIMM)and a Multi-sample Joint Triplet Loss(MJT Loss).Specifically,DIMM incorporates the interdependence between different spatial regions of the feature map in the cascaded convolutional unit group,which enhances the model’s attention to the domain-invariant static object class.MJT Loss introduces the“joint processing of multiple samples”mechanism into the original triplet loss,and adds a new distance constraint term for“positive and negative”samples,so that the model can avoid falling into local optimum during training.We demonstrate the effectiveness of our algorithm by conducting extensive experiments on several authoritative benchmarks.In particular,the proposed method achieves the best performance on the TokyoTM dataset with a Recall@1 metric of 92.89%.
基金financially supported by the Less Developed Regions of the National Natural Science Foundation of China(Grant No.52065058)the Graduate Education Innovation Project of Xinjiang Uygur Autonomous Region(Grant No.XJ2022G085)+1 种基金the Open Fund of Jiangsu Province and Education Ministry Co-sponsored Synergistic Innovation Center of Modern Agricultural Equipment,(Grant No.XTCX2006)the key industry innovation development support plan of southern Xinjiang(Grant No.2020DB008).
文摘In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulation model and numerical simulation were established using the discrete element software EDEM.Then a second-order response model between contact parameters and repose angle had been constructed.The test result showed that the static friction coefficient,rolling friction coefficient,and coefficient of restitution between cotton stems were crucial factors affecting the repose angle.The determination coefficient corrected determination coefficient and p-value of the second-order response model were R^(2)=0.959,R^(2)_(adj)=0.921,and p<0.0001 respectively.The error values of the comparison between the simulation test results and the corresponding physical test values were all less than 10%,which showed that the model was reliable and had high interpretation and predictability,this study can provide a certain theoretical basis and data support for the setting of contact parameters in the data simulation of cotton stem harvesting and processing,mechanically-harvested film residue crushing and film stem separation,etc.
基金the National Natural Science Foundation of China(Nos.22075211,21601136,51971157,62005173,and 51621003)Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016),Guangdong Third Generation Semiconductor Engineering Technology Development Center(No.2020GCZX007)+2 种基金Science,Technology,and Innovation Commission of Shenzhen Municipality(No.RCBS20200714114818140)China Postdoctoral Science Foundation(No.2019M663118)School level scientific research project of Shenzhen Institute of information technology(No.PT2019E002).
文摘The electrosynthesis of hydrogen peroxide(H2O2)from oxygen reduction reaction(ORR)via a two-electron pathway provides an appealing alternative to the energy-intensive anthraquinone route;however,the development of ORR with high selectivity and durability for H2O2 production is still challenging.Herein,we demonstrate an active and stable catalyst,composing of highly dispersed Ag nanoclusters on N-doped hollow carbon spheres(NC-Ag/NHCS),which can effectively reduce O2 molecules into H2O2 with a selectivity of 89%–91%in a potential range from 0.2 to 0.7 V(vs.reversible hydrogen electrode(RHE))in acidic media.Strikingly,NC-Ag/NHCS achieve a mass activity of 27.1 A·g^(−1) and a yield rate of 408 mmol·gcat.^(−1)·h^(−1) at 0.7 V,both of which are comparable with the best-reported results.Furthermore,NC-Ag/NHCS enable catalyzing H2O2 production with a stable current density over 48-h electrolysis and only about 9.8%loss in selectivity after 10,000 cycles.Theoretical analyses indicate that Ag nanoclusters can contribute more electrons to favor the protonation of adsorbed O2,thus leading to a high H2O2 selectivity.This work confirms the great potential of metal nanocluster-based materials for H2O2 electrosynthesis under ambient conditions.
基金the financial support from the China Postdoctoral Science Foundation(No.2022M710606(Z.C.Y.))the National Natural Science Foundation of China(Nos.61825102 and U21A20460(Y.L.))+3 种基金the Fundamental Research Funds for the Central Universities of UESTC(No.ZYGX2021YGLH002(Y.L.))the Shenzhen Science and technology planning project(No.JSGG20201102152403008(T.H.))the Project of Innovation and Strong School(No.PT2020C002(X.Z.W.))the Science and Technology Project of Shenzhen City(No.JSGG20210802154213040(X.Z.W.)).
文摘The successful implementation of bioelectronic devices attached to living organism hinges on a number of material and device characteristics,including not only electrical and mechanical performances to gather physiological signals from living organism thus enabling status monitoring,but also permeability or breathability for gas/nutrient exchange between living organisms and surroundings to ensure minimum perturbation of the intrinsic biological function.However,most bioelectronic devices built on planar polymeric substrates,such as polydimethylsiloxane(PDMS),polyurethane(PU),and polyimide(PI),lack efficient gas permeability,which may hinder the emission of volatile compounds from the surface of living organism,affecting the natural metabolism and reducing the comfort of wearing.Thus,achieving permeability or breathability in bioelectronic devices is a significant challenge.Currently,the devices made of gas-permeable materials with porous structures,that combine electronic components with daily garments,such as fibric and textile,offer exciting opportunities for breathable electronics.In this review,several types of gas-permeable materials with their synthesis and processing routes are outlines.Then,two methods for measuring water vapor transmission rate of materials are discussed in depth.Finally,recent progress in the use of gaspermeable materials for the applications of plant-and skin-attached electronics is summarized systematically.
文摘In-depth understandings of charge carrier transfer dynamics in any artificial catalytic system are of critical importance for the future design of highly efficient photocatalysts.Herein,we synthesized sub-monolayer ZnSe partial-shell coated CdSe/CdS core/shell quantum dots in a controlled fashion.The ZnSe decorated quantum dots were employed as a model catalyst for photogeneration of H_(2)under light illumination.Both theoretical calculations and experimental results unravel that the growth of ZnSe partial-shell would retard the photogenerated electron transfer,and meanwhile,accelerate the corresponding hole migration process during the H_(2)photogeneration reaction in the artificial photocatalytic system.As such,the performance of the relevant photocatalytic system can be modulated and optimized,and accordingly,a plausible underlying mechanism is rationalized.
基金supported by the National Natural Science Foundation of China(No.22105023).
文摘Searching for insensitive melt-castable energetic materials is still facing great challenges.In this work,we developed a promising strategy that is regulating the ratio of non-covalent interaction by fluorine atoms to regulate the melting point to develop new melt-castable energetic materials.Using this method,a highly sym-metric 1,2-difluoro-4,5-dinitrobenzene(DFDNB)was synthesized in one step and fully characterized.DFDNB has a desirable melting point(83.2℃),high decomposition temperature(>400℃),acceptable detonation properties(6786 m s^(-1),21.5 GPa)but superior safety performance(>40 J,>360 N),and excellent chemical compatibility with 1,3,5-trinitro-1,3,5-triazine(RDX)that make it a promising insensitive melt-castable energetic material.A detailed study based on crystal stacking,electrostatic potential,and intermolecular weak interactions in DFDNB and its isomers or analogs demonstrates that non-covalent interactions including the C-F…H,N-O…H hydrogen bonding,and C-F…O halogen-like bonding play an important role in regulating the melting point.
基金funded by the National Key Research and Development Program(No.2019YFC1804400)the National Natural Science Foundation of China(Nos.21974124,22004109,22076174)+3 种基金Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016)Guangdong Third Generation Semiconductor Engineering Technology Development Center(No.2020GCZX007)the Yunnan Provincial Science and Technology Bureau and the Double Top Joint Fund of Yunnan University(No.2019FY003025)the Double First Class University Plan(No.C176220100042)。
文摘Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat(PQ),a toxic herbicide,in aqueous environments.A linear experiment performed using square wave voltammetry(SWV)under optimized experimental conditions produced a decent linear relationship and a low detection limit(LOD)of 2.74 nmol/L(S/N=3).Repeatability,reproducibility,stability,and interference experiments confirmed that the Fe_(2)O_(3)–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules.Notably,the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples.To the best of our knowledge,this is the first study on the preparation of Fe_(2)O_(3)–BCN nanosheets for PQ detection.The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.
基金financially supported by the Fund for Less Developed Regions of the National Natural Science Foundation of China(Grant No.52065058)Graduate Education Innovation Project of Xinjiang Uygur Autonomous Region(Grant No.Xj2022G085)+2 种基金the Key Industry Innovation Development Support Plan of South Xinjiang(Grant No.2020DB008)the Open Fund of Jiangsu Province and Education Ministry Co-sponsored Synergistic Innovation Center of Modern Agricultural Equipment(Grant No.XTCX2006)Scientific and technological innovation team of Xinjiang Production and Construction Corps(Grant No.2020CB013).
文摘As the existing residual film crushing device in Xinjiang cannot directly crush membrane-impurity mixed material,by analyzing the compressive and cutting force characteristics of residual film material layer and cotton stalk,the cutting conditions of mixed materials were obtained,and the method of cutting was determined.A multi-edge toothed cutters was created,and a cutting device was built.It was preliminarily determined that the number of teeth in the cutters was 8,the clearance between the teeth and between the tooth and fixed blade was 3 mm,the speed of the high-speed cutter was 800 r/min,and the speed difference between the high-and low-speed cutters was-300 r/min.Test results show that the ratio of residual film to total residual film sampling mass was(2.22±0.30)%,(19.19±2.02)%,(58.94±3.19)% and(20.65±2.05)%,respectively,when the maximum outer profile size in the range of[0,20)mm,[20,100)mm,[100,500)mm and[500,~)mm.The mass of cotton stalks with lengths of[0,50)mm,[50,100)mm and[100,~)mm accounted for(32.57±1.5)%,(27.77±1.3)%and(39.66±1.75)%,respectively,and the cutting power consumption was(85.41±15.63)kJ.The test results can provide a basis for the subsequent membrane-impurity mixed material cutting technology,as well as some guidance for the separation of it.
基金This work was financially supported by the funding of the Southern Xinjiang Key Industry Innovation and Development Support Program(Grant No.2020DB008)the Graduate Education Innovation Project of Xinjiang Uygur Autonomous Region(Grant No.XJ2022G085)+1 种基金the Open Fund of Jiangsu Province and Education Ministry Co-sponsored Synergistic Innovation Center of Modern Agricultural Equipment(Grant No.XTCX2006)the National Natural Science Foundation of China(Grant No.52065058).
文摘The restitution coefficient(RC)of cotton stalks is an important elementary physical parameter that is required to establish the crushing mechanical model and research the film residue separation machinery.In this study,the calculation method of restitution coefficient considering the rotation motion of stalk-shaped agricultural materials was derived based on the principle of kinematics and the energy restitution coefficient method,and a test bench for measuring the RC was designed and built.The effects of collision material,moisture content,length,diameter,release height,and collision angle respectively on the RC were investigated by single-factor experiments and orthogonal experiments,and the regression models between influence factors and the RC were established.The results showed that Q235 showed the highest value of the RC,and it was followed by cotton stalks and soil lumps,sequentially.The RC of cotton stalks decreased with the increase of moisture content and diameter,while it increased at first and then decreased with the increase of length.As the release height was less than 500 mm,the RC increased with the increased release height.As the collision angle was less than 40°,the RC showed a linear increasing trend.The significance of the effects of factors on RC decreased with the following sequence:collision angle,length,release height,diameter,and moisture content.Length,collision angle,and release height were extremely significant.The contrast test results showed that the values based on Newton’s restitution coefficient method were smaller than that based on the energy restitution coefficient method.The verification test showed that the predicted rebound height of cotton stalks calculated based on the energy restitution coefficient method was closer to the actual rebound height,and the relative error was less than 5%.
