Fast and accurate measurement of the volume of earthmoving materials is of great signifcance for the real-time evaluation of loader operation efciency and the realization of autonomous operation. Existing methods for ...Fast and accurate measurement of the volume of earthmoving materials is of great signifcance for the real-time evaluation of loader operation efciency and the realization of autonomous operation. Existing methods for volume measurement, such as total station-based methods, cannot measure the volume in real time, while the bucket-based method also has the disadvantage of poor universality. In this study, a fast estimation method for a loader’s shovel load volume by 3D reconstruction of material piles is proposed. First, a dense stereo matching method (QORB–MAPM) was proposed by integrating the improved quadtree ORB algorithm (QORB) and the maximum a posteriori probability model (MAPM), which achieves fast matching of feature points and dense 3D reconstruction of material piles. Second, the 3D point cloud model of the material piles before and after shoveling was registered and segmented to obtain the 3D point cloud model of the shoveling area, and the Alpha-shape algorithm of Delaunay triangulation was used to estimate the volume of the 3D point cloud model. Finally, a shovel loading volume measurement experiment was conducted under loose-soil working conditions. The results show that the shovel loading volume estimation method (QORB–MAPM VE) proposed in this study has higher estimation accuracy and less calculation time in volume estimation and bucket fll factor estimation, and it has signifcant theoretical research and engineering application value.展开更多
Ferroelectric polymer nanocomposites possess exceptional electric properties with respect to the two otherwise uniform phases,which is commonly attributed to the critical role of the matrix-particle interfacial region...Ferroelectric polymer nanocomposites possess exceptional electric properties with respect to the two otherwise uniform phases,which is commonly attributed to the critical role of the matrix-particle interfacial region.However,the structure-property correlation of the interface remains unestablished,and thus,the design of ferroelectric polymer nanocompos-ite has largely relied on the trial-and-error method.Here,a strategy that combines multi-mode scanning probe microscopy-based electrical charac-terization and nano-infrared spectroscopy is developed to unveil the local structure-property correlation of the interface in ferroelectric polymer nano-composites.The results show that the type of surface modifiers decorated on the nanoparticles can significantly influence the local polar-phase content and the piezoelectric effect of the polymer matrix surrounding the nano-particles.The strongly coupled polar-phase content and piezoelectric effect measured directly in the interfacial region as well as the computed bonding energy suggest that the property enhancement originates from the formation of hydrogen bond between the surface modifiers and the ferroelectric polymer.It is also directly detected that the local domain size of the ferroelectric polymer can impact the energy level and distribution of charge traps in the interfacial region and eventually influence the local dielectric strength.展开更多
A B-spline Interpolation Transport Solver(BITS) based on a collocation method is developed. It solves transport equations as a generalized interpolation problem, taking the first-order accuracy in time and the second-...A B-spline Interpolation Transport Solver(BITS) based on a collocation method is developed. It solves transport equations as a generalized interpolation problem, taking the first-order accuracy in time and the second-order accuracy in space along with a predictor–corrector or under-relaxation iteration method. Numerical tests show that BITS can solve one-dimensional transport equations for tokamak plasma more accurately without additional computation cost, compared to the finite difference method transport solver which is widely used in existing tokamak transport codes.展开更多
A simple, rapid and sensitive method based on an ultra-performance liquid chromatography–tandem mass spectrometry(UPLC–MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The...A simple, rapid and sensitive method based on an ultra-performance liquid chromatography–tandem mass spectrometry(UPLC–MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C_(18) column(100 mm × 2.1 mm, 1.7 μm; Waters, USA), with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate(70:30, v/v), at a flow rate of 0.2 m L/min for 2.5 min. The analyte and clarithromycin(the internal standard) were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 → 223.0 for pimavanserin and m/z 748.5 → 589.5 for clarithromycin. Relative coefficient(r) for the calibration curve was more than 0.9980. The intra-day and inter-day precisions(relative standard deviation, RSD%) were less than 13.3% and 10.5%, respectively, and the accuracy(relative error, RE%) was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.展开更多
The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection functi...The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.展开更多
The genomic scale metabolic networks of the microorganisms can be constructed based on their genome se-quences,functional annotations,and biochemical reactions,reflecting almost all of the metabolic functions.Mathemat...The genomic scale metabolic networks of the microorganisms can be constructed based on their genome se-quences,functional annotations,and biochemical reactions,reflecting almost all of the metabolic functions.Mathematical simulations of metabolic fluxes could make these functions be visualized,thereby providing guidance for rational engineering design and experimental operations.This review summarized recently devel-oped flux simulation algorithms of microbial systems.For the single microbial systems,the optimal planning algorithm has low complexity because there is no interaction between microorganisms,and it can quickly simulate the stable metabolic states through the pseudo-steady hypothesis.Besides,the experimental conditions of single microbial systems are easier to reach or close to the optimal states of simulation,compared with pol-ymicrobial systems.The polymicrobial culture systems could outcompete the single microbial systems as they could relieve metabolic pressure through metabolic division,resource exchange,and complex substrate co-utilization.Besides,they provide varieties of intracellular production environments,which render them the po-tential to achieve efficient bioproduct synthesis.However,due to the quasi-steady hypothesis that restricts the simulation of the dynamic processes of microbial interactions and the algorithm complexity,there are few re-searches on simulation algorithms of polymicrobial metabolic fluxes.Therefore,this review also analyzed and combed the microbial interactions based on the commonly used hypothesis of maximizing growth rates,and studied the strategies of coupling interactions with optimal planning simulations for metabolism.Finally,this review provided new insights into the genomic scale metabolic flux simulations of polymicrobial systems.展开更多
Achieving full-polarization(σ)invisibility on an arbitrary three-dimensional(3D)platform is a long-held knotty issue yet extremely promising in real-world stealth applications.However,state-of-the-art invisibility cl...Achieving full-polarization(σ)invisibility on an arbitrary three-dimensional(3D)platform is a long-held knotty issue yet extremely promising in real-world stealth applications.However,state-of-the-art invisibility cloaks typically work under a specific polarization because the anisotropy and orientation-selective resonant nature of artificial materials made theσ-immune operation elusive and terribly challenging.Here,we report a deterministic approach to engineer a metasurface skin cloak working under an arbitrary polarization state by theoretically synergizing two cloaking phase patterns required,respectively,at spin-up(σ+)and spin-down(σ−)states.Therein,the wavefront of any light impinging on the cloak can be well preserved since it is a superposition ofσ+andσ−wave.To demonstrate the effectiveness and applicability,several proof-of-concept metasurface cloaks are designed to wrap over a 3D triangle platform at microwave frequency.Results show that our cloaks are essentially capable of restoring the amplitude and phase of reflected beams as if light was incident on a flat mirror or an arbitrarily predesigned shape under full polarization states with a desirable bandwidth of~17.9%,conceiving or deceiving an arbitrary object placed inside.Our approach,deterministic and robust in terms of accurate theoretical design,reconciles the milestone dilemma in stealth discipline and opens up an avenue for the extreme capability of ultrathin 3D cloaking of an arbitrary shape,paving up the road for real-world applications.展开更多
Ecological stoichiometry provides the possibility for linking microbial dynamics with soil carbon(C),nitrogen(N),and phosphorus(P)metabolisms in response to agricultural nutrient management.To determine the roles of f...Ecological stoichiometry provides the possibility for linking microbial dynamics with soil carbon(C),nitrogen(N),and phosphorus(P)metabolisms in response to agricultural nutrient management.To determine the roles of fertilization and residue return with respect to ecological stoichiometry,we collected soil samples from a 30-year field experiment on residue return(maize straw)at rates of 0,2.5,and 5.0 Mg ha^-1 in combination with 8 fertilization treatments:no fertilizer(F0),N fertilizer,P fertilizer,potassium(K)fertilizer,N and P(NP)fertilizers,N and K(NK)fertilizers,P and K(PK)fertilizers,and N,P,and K(NPK)fertilizers.We measured soil organic C(SOC),total N and P,microbial biomass C,N,and P,water-soluble organic C and N,KMnO4-oxidizabIe C(KMnO4-C),and carbon management index(CMI).Compared with the control(F0 treatment without residue return),fertilization and residue return significantly increased the KMn〇4-C content and CMI.Furthermore,compared with the control,residue return significantly increased the SOC content.Moreover,the NPK treatment with residue return at 5.0 Mg ha^-1 significantly enhanced the C:N,C:P,and N:P ratios in the soil,whereas it significantly decreased the C:N and C:P ratios in soil microbial biomass.Therefore,NPK fertilizer application combined with residue return at 5.0 Mg ha^-1 could enhance the SOC content through the stoichiometric plasticity of microorganisms.Residue return and fertilization increased the soil C pools by directly modifying the microbial stoichiometry of the biomass that was C limited.展开更多
Smart materials,such as stimuli-responsive luminescence,have attracted much attentions due to their potential application in semiconductor filed.In this context,platinum complexes of(dfppy-DC)Pt(acac) and(dfppy-O-DC)P...Smart materials,such as stimuli-responsive luminescence,have attracted much attentions due to their potential application in semiconductor filed.In this context,platinum complexes of(dfppy-DC)Pt(acac) and(dfppy-O-DC)Pt(acac) were prepared and characterized,in which(2-(4',6'-difluorophenyl)pyridinato-N,C2')(2,4-pentanedionato-0,0)Pt(Ⅱ) was used as the planar emission core and 9-(4-(phenylsulfonyl)phenyl)-9 H-carbazole(DC) was regard as the bent pendent.Both platinum complexes showed bright emission in solution and solid state,concomitant with charming external-stimuli-responsive emission under mechanical grinding,organic solvent vapors and pressure.The change emission color spanned from yellow to near-infrared region.Using the platinum complexes as the dopant,solution processable organic light-emitting diodes(OLEDs) were fabricated and a maximum external quantum efficiency of ~18% was achieved,which is the highest value among the reported solution-processable OLEDs based on externalstimuli-responsive luminescence.This research demonstrated that platinum complex can show promising stimuli responsive emission via ingenious molecular design,indicating a novel way for developing the smart materials in semiconductor filed.展开更多
Electromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible.Most transformation-optics(TO)cloaks intrinsically need wavelength-scale volume/thickness,suc...Electromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible.Most transformation-optics(TO)cloaks intrinsically need wavelength-scale volume/thickness,such that the incoming waves could have enough long paths to interact with structured meta-atoms in the cloak region and consequently restore the wavefront.Other challenges of TO cloaks include the polarization-dependent operation to avoid singular parameters of composite cloaking materials and limitations of canonical geometries,e.g.,circular,elliptical,trapezoidal,and triangular shapes.Here,we report for the first time a conformal-skin metasurface carpet cloak,enabling to work under arbitrary states of polarization(SOP)at Poincarésphere for the incident light and arbitrary conformal platform of the object to be cloaked.By exploiting the foundry three-dimensional(3D)printing techniques to fabricate judiciously designed meta-atoms on the external surface of a conformal object,the spatial distributions of intensity and polarization of its scattered lights can be reconstructed exactly the same as if the scattering wavefront were deflected from a flat ground at any SOP,concealing targets under polarization-scanning detections.Two conformal-skin carpet cloaks working for partial-and full-azimuth plane operation are respectively fabricated on trapezoid and pyramid platforms via 3D printing.Experimental results are in good agreement with numerical simulations and both demonstrate the polarization-insensitive cloaking within a desirable bandwidth.Our approach paves a deterministic and robust step forward to the realization of interfacial,free-form,and full-polarization cloaking for a realistic arbitrary-shape target in real-world applications.展开更多
Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate...Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate that the bowl-shaped clusters C_(18)Te_(3)Br_(4)(Bu-O)_(6) might experience a DDA reaction at room temperature and high pressure between 5.5 and 7.4 GPa.Above 17.0 GPa,it is found that the bonding conversion from the intramolecular sp^(2) to the intermolecular spa occurred,in the form of pressure-induced diamondization.The recovered samples from 20.0 and 36.1 GPa showed incomplete reversibility,while the decompression-induced graphitization of glassy carbon was observed during decompression from 46.5 GPa.The electrochemical impedance spectroscopy results indicated that the transport properties changed from grain boundary dominant to grain dominant due to the DDA reaction and the grain boundary effect disappeared as the intermolecular sp3 bonding building-up and carrier transmission channel formation above 17.0 GPa.The results in this study open a new route to construct the crystalline carbon materials with different transport properties.展开更多
Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in a...Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in an on-demand manner.Recently,kirigami technique,affording versatile and unconventional structural transformation,has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner.Here,we report for a kirigami-inspired sparse meta-architecture,with structural density of 1.5%in terms of the occupation space,for adaptive invisibility based on independent operations of frequency,bandwidth,and amplitude.Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures,we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers(A,B,and C)of different geometries characterized by the folding angleβ.Our strategy circumvents issues of limited abilities,narrow tuning range,extreme condition,and high cost raised by available reconfigurable metamaterials,providing a new avenue toward multifunctional smart devices.展开更多
Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in a...Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in an on-demand manner.Recently,kirigami technique,affording versatile and unconventional structural transformation,has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner.Here,we report for a kirigami-inspired sparse meta-architecture,with structural density of 1.5%in terms of the occupation space,for adaptive invisibility based on independent operations of frequency,bandwidth,and amplitude.Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures,we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers(A,B,and C)of different geometries characterized by the folding angleβ.Our strategy circumvents issues of limited abilities,narrow tuning range,extreme condition,and high cost raised by available reconfigurable metamaterials,providing a new avenue toward multifunctional smart devices.展开更多
基金Supported by National Key R&D Program of China(Grant Nos.2020YFB1709901 and 2020YFB1709904)National Natural Science Foundation of China(Grant Nos.51975495 and 51905460)+1 种基金Guangdong Provincial Basic and Applied Basic Research Foundation(Grant No.2021A1515012286)Guiding Funds of Central Government for Supporting the Development of the Local Science and Technology(Grant No.2022L3049).
文摘Fast and accurate measurement of the volume of earthmoving materials is of great signifcance for the real-time evaluation of loader operation efciency and the realization of autonomous operation. Existing methods for volume measurement, such as total station-based methods, cannot measure the volume in real time, while the bucket-based method also has the disadvantage of poor universality. In this study, a fast estimation method for a loader’s shovel load volume by 3D reconstruction of material piles is proposed. First, a dense stereo matching method (QORB–MAPM) was proposed by integrating the improved quadtree ORB algorithm (QORB) and the maximum a posteriori probability model (MAPM), which achieves fast matching of feature points and dense 3D reconstruction of material piles. Second, the 3D point cloud model of the material piles before and after shoveling was registered and segmented to obtain the 3D point cloud model of the shoveling area, and the Alpha-shape algorithm of Delaunay triangulation was used to estimate the volume of the 3D point cloud model. Finally, a shovel loading volume measurement experiment was conducted under loose-soil working conditions. The results show that the shovel loading volume estimation method (QORB–MAPM VE) proposed in this study has higher estimation accuracy and less calculation time in volume estimation and bucket fll factor estimation, and it has signifcant theoretical research and engineering application value.
基金supported by the National Natural Science Foundation of China(Nos.51922056 and 51921005).
文摘Ferroelectric polymer nanocomposites possess exceptional electric properties with respect to the two otherwise uniform phases,which is commonly attributed to the critical role of the matrix-particle interfacial region.However,the structure-property correlation of the interface remains unestablished,and thus,the design of ferroelectric polymer nanocompos-ite has largely relied on the trial-and-error method.Here,a strategy that combines multi-mode scanning probe microscopy-based electrical charac-terization and nano-infrared spectroscopy is developed to unveil the local structure-property correlation of the interface in ferroelectric polymer nano-composites.The results show that the type of surface modifiers decorated on the nanoparticles can significantly influence the local polar-phase content and the piezoelectric effect of the polymer matrix surrounding the nano-particles.The strongly coupled polar-phase content and piezoelectric effect measured directly in the interfacial region as well as the computed bonding energy suggest that the property enhancement originates from the formation of hydrogen bond between the surface modifiers and the ferroelectric polymer.It is also directly detected that the local domain size of the ferroelectric polymer can impact the energy level and distribution of charge traps in the interfacial region and eventually influence the local dielectric strength.
基金the National MCF Energy R&D Program of China(No.2019YFE03040004)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)the National MCF Energy R&D Program of China(No.2019YFE03060000)。
文摘A B-spline Interpolation Transport Solver(BITS) based on a collocation method is developed. It solves transport equations as a generalized interpolation problem, taking the first-order accuracy in time and the second-order accuracy in space along with a predictor–corrector or under-relaxation iteration method. Numerical tests show that BITS can solve one-dimensional transport equations for tokamak plasma more accurately without additional computation cost, compared to the finite difference method transport solver which is widely used in existing tokamak transport codes.
基金supported in part by a grant of the Scientific Research Program of Hainan Province (ZDYF2016143), China
文摘A simple, rapid and sensitive method based on an ultra-performance liquid chromatography–tandem mass spectrometry(UPLC–MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C_(18) column(100 mm × 2.1 mm, 1.7 μm; Waters, USA), with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate(70:30, v/v), at a flow rate of 0.2 m L/min for 2.5 min. The analyte and clarithromycin(the internal standard) were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 → 223.0 for pimavanserin and m/z 748.5 → 589.5 for clarithromycin. Relative coefficient(r) for the calibration curve was more than 0.9980. The intra-day and inter-day precisions(relative standard deviation, RSD%) were less than 13.3% and 10.5%, respectively, and the accuracy(relative error, RE%) was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.
文摘The main advantage of digital PCR(dPCR) is that it facilitates absolute quantification of the target without reference to the standard/calibration curve.Crystal droplet dPCR has a three-color staining detection function,which enables multiplex PCR reaction.In this study,this technique was used to establish triple dPCR detection for the genetically modified soybean MON87708 × MON89788 with stacked traits.Specific absolute quantitative detection was accomplished for the genomic DNA extracted from the homogenized seeds of GM stack MON87708× MON89788 soybean.Our results can serve as a reference for the absolute quantitative detection of stacked events of genetically modified crops.
基金support from the National Key R&D Program of China(2021YFC2100700)the National Natural Science Foundation of China(21838001,31961133018).
文摘The genomic scale metabolic networks of the microorganisms can be constructed based on their genome se-quences,functional annotations,and biochemical reactions,reflecting almost all of the metabolic functions.Mathematical simulations of metabolic fluxes could make these functions be visualized,thereby providing guidance for rational engineering design and experimental operations.This review summarized recently devel-oped flux simulation algorithms of microbial systems.For the single microbial systems,the optimal planning algorithm has low complexity because there is no interaction between microorganisms,and it can quickly simulate the stable metabolic states through the pseudo-steady hypothesis.Besides,the experimental conditions of single microbial systems are easier to reach or close to the optimal states of simulation,compared with pol-ymicrobial systems.The polymicrobial culture systems could outcompete the single microbial systems as they could relieve metabolic pressure through metabolic division,resource exchange,and complex substrate co-utilization.Besides,they provide varieties of intracellular production environments,which render them the po-tential to achieve efficient bioproduct synthesis.However,due to the quasi-steady hypothesis that restricts the simulation of the dynamic processes of microbial interactions and the algorithm complexity,there are few re-searches on simulation algorithms of polymicrobial metabolic fluxes.Therefore,this review also analyzed and combed the microbial interactions based on the commonly used hypothesis of maximizing growth rates,and studied the strategies of coupling interactions with optimal planning simulations for metabolism.Finally,this review provided new insights into the genomic scale metabolic flux simulations of polymicrobial systems.
基金The authors express their thanks for the support from the National Natural Science Foundation of China （Grant No. 21525625）, the National Basic Research Program of China （973 Program, Grant No. 2014CB745100）, the National High Technology Research and Development Program of China （863 Program, Grant No. 2013AA020302）.
文摘从经由一个混合文化黑暗发酵过程的未加工的木薯淀粉的简历氢的生产被调查。H <sub>2</sub> 的生产收益被调整底层集中和微生物混合比率优化。1.72 摩尔 H <sub>2</sub>/mol 葡萄糖的最大的 H <sub>2</sub> 收益与 10 g/L 的木薯淀粉集中被获得给 90% 利用率。底层利用并且氢和不稳定的丰满的酸的产生的动力学也被调查。底层利用列在后面假首先订反应动力学，而两 H <sub>2</sub> 的生产和 VFA 与 Gompertz 方程相关。这些结果证明那棵木薯是 biohydrogen 的生产的一个好候选人。
基金supports by the National Defense Foundation of China(2019-JCJQ-JJ-081)Youth Talent Lifting Project of the China Association for Science and Technology(17-JCJQ-QT-003)+4 种基金Key Program of Natural Science Foundation of Shaanxi Province(2020JZ-33)Key Principal’s Fund of Air Force Engineering University(XNLX19030601)Villum Fonden of Denmark(Grant No.00022988)the National Key Research and Development Program of China(Grant NO.2017YFA0700202)the National Natural Science Foundation of China(61701082).
文摘Achieving full-polarization(σ)invisibility on an arbitrary three-dimensional(3D)platform is a long-held knotty issue yet extremely promising in real-world stealth applications.However,state-of-the-art invisibility cloaks typically work under a specific polarization because the anisotropy and orientation-selective resonant nature of artificial materials made theσ-immune operation elusive and terribly challenging.Here,we report a deterministic approach to engineer a metasurface skin cloak working under an arbitrary polarization state by theoretically synergizing two cloaking phase patterns required,respectively,at spin-up(σ+)and spin-down(σ−)states.Therein,the wavefront of any light impinging on the cloak can be well preserved since it is a superposition ofσ+andσ−wave.To demonstrate the effectiveness and applicability,several proof-of-concept metasurface cloaks are designed to wrap over a 3D triangle platform at microwave frequency.Results show that our cloaks are essentially capable of restoring the amplitude and phase of reflected beams as if light was incident on a flat mirror or an arbitrarily predesigned shape under full polarization states with a desirable bandwidth of~17.9%,conceiving or deceiving an arbitrary object placed inside.Our approach,deterministic and robust in terms of accurate theoretical design,reconciles the milestone dilemma in stealth discipline and opens up an avenue for the extreme capability of ultrathin 3D cloaking of an arbitrary shape,paving up the road for real-world applications.
基金This research was financially supported by the Special Foundation for State Major Basic Research Program of China(No.2016YFC0501202)the Special Foundation for Basic Research Program in Soil of Chinese Academy Sciences(Nos.XDB 15030103 and XDA23070501)+2 种基金the National Natural Science Foundation of China(Nos.41920104008 and 41701332)the Key Laboratory Foundation of Mollisols Agroecology(No.2016ZKHT-05)the 135 Project of Northeast Institute of Geography and Agroecology of Chinese Academy Sciences(No.Y6H2043001).
文摘Ecological stoichiometry provides the possibility for linking microbial dynamics with soil carbon(C),nitrogen(N),and phosphorus(P)metabolisms in response to agricultural nutrient management.To determine the roles of fertilization and residue return with respect to ecological stoichiometry,we collected soil samples from a 30-year field experiment on residue return(maize straw)at rates of 0,2.5,and 5.0 Mg ha^-1 in combination with 8 fertilization treatments:no fertilizer(F0),N fertilizer,P fertilizer,potassium(K)fertilizer,N and P(NP)fertilizers,N and K(NK)fertilizers,P and K(PK)fertilizers,and N,P,and K(NPK)fertilizers.We measured soil organic C(SOC),total N and P,microbial biomass C,N,and P,water-soluble organic C and N,KMnO4-oxidizabIe C(KMnO4-C),and carbon management index(CMI).Compared with the control(F0 treatment without residue return),fertilization and residue return significantly increased the KMn〇4-C content and CMI.Furthermore,compared with the control,residue return significantly increased the SOC content.Moreover,the NPK treatment with residue return at 5.0 Mg ha^-1 significantly enhanced the C:N,C:P,and N:P ratios in the soil,whereas it significantly decreased the C:N and C:P ratios in soil microbial biomass.Therefore,NPK fertilizer application combined with residue return at 5.0 Mg ha^-1 could enhance the SOC content through the stoichiometric plasticity of microorganisms.Residue return and fertilization increased the soil C pools by directly modifying the microbial stoichiometry of the biomass that was C limited.
基金Financial support was from the National Natural Science Foundation of China(Nos.51773021,51911530197,U1663229)Six Talent Peaks Project in Jiangsu Province(No.XCL-102)the Talent Project of Jiangsu Specially-Appointed Professor,Natural Science Fund for Colleges and Universities in Jiangsu Province(No.19KJA430002)。
文摘Smart materials,such as stimuli-responsive luminescence,have attracted much attentions due to their potential application in semiconductor filed.In this context,platinum complexes of(dfppy-DC)Pt(acac) and(dfppy-O-DC)Pt(acac) were prepared and characterized,in which(2-(4',6'-difluorophenyl)pyridinato-N,C2')(2,4-pentanedionato-0,0)Pt(Ⅱ) was used as the planar emission core and 9-(4-(phenylsulfonyl)phenyl)-9 H-carbazole(DC) was regard as the bent pendent.Both platinum complexes showed bright emission in solution and solid state,concomitant with charming external-stimuli-responsive emission under mechanical grinding,organic solvent vapors and pressure.The change emission color spanned from yellow to near-infrared region.Using the platinum complexes as the dopant,solution processable organic light-emitting diodes(OLEDs) were fabricated and a maximum external quantum efficiency of ~18% was achieved,which is the highest value among the reported solution-processable OLEDs based on externalstimuli-responsive luminescence.This research demonstrated that platinum complex can show promising stimuli responsive emission via ingenious molecular design,indicating a novel way for developing the smart materials in semiconductor filed.
基金This work was supported by the National Defense Foundation of China(2019-JCJQ-JJ-081)the Youth Talent Lifting Project of the China Association for Science and Technology(17-JCJQ-QT-003)+3 种基金the Key Program of Natural Science Foundation of Shaanxi Province(2020JZ-33)the Key Principal’s Fund of Air Force Engineering University(XNLX19030601)the National Key Research and Development Program of China(2017YFA0700202)the National Natural Science Foundation of China(61701082).
文摘Electromagnetic metasurface cloaks provide an alternative paradigm toward rendering arbitrarily shaped scatterers invisible.Most transformation-optics(TO)cloaks intrinsically need wavelength-scale volume/thickness,such that the incoming waves could have enough long paths to interact with structured meta-atoms in the cloak region and consequently restore the wavefront.Other challenges of TO cloaks include the polarization-dependent operation to avoid singular parameters of composite cloaking materials and limitations of canonical geometries,e.g.,circular,elliptical,trapezoidal,and triangular shapes.Here,we report for the first time a conformal-skin metasurface carpet cloak,enabling to work under arbitrary states of polarization(SOP)at Poincarésphere for the incident light and arbitrary conformal platform of the object to be cloaked.By exploiting the foundry three-dimensional(3D)printing techniques to fabricate judiciously designed meta-atoms on the external surface of a conformal object,the spatial distributions of intensity and polarization of its scattered lights can be reconstructed exactly the same as if the scattering wavefront were deflected from a flat ground at any SOP,concealing targets under polarization-scanning detections.Two conformal-skin carpet cloaks working for partial-and full-azimuth plane operation are respectively fabricated on trapezoid and pyramid platforms via 3D printing.Experimental results are in good agreement with numerical simulations and both demonstrate the polarization-insensitive cloaking within a desirable bandwidth.Our approach paves a deterministic and robust step forward to the realization of interfacial,free-form,and full-polarization cloaking for a realistic arbitrary-shape target in real-world applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.52090020 and 11874076)the National Research Foundation of Korea(Nos.2016K1A4A3914691 and 2018R1DA1B070498).
文摘Dehydro-Diels-Alder(DDA)reaction is a textbook reaction for preparing six-membered rings in solution but is scarcely seen in solid-state synthesis.In this work,using multiple characterization techniques,we demonstrate that the bowl-shaped clusters C_(18)Te_(3)Br_(4)(Bu-O)_(6) might experience a DDA reaction at room temperature and high pressure between 5.5 and 7.4 GPa.Above 17.0 GPa,it is found that the bonding conversion from the intramolecular sp^(2) to the intermolecular spa occurred,in the form of pressure-induced diamondization.The recovered samples from 20.0 and 36.1 GPa showed incomplete reversibility,while the decompression-induced graphitization of glassy carbon was observed during decompression from 46.5 GPa.The electrochemical impedance spectroscopy results indicated that the transport properties changed from grain boundary dominant to grain dominant due to the DDA reaction and the grain boundary effect disappeared as the intermolecular sp3 bonding building-up and carrier transmission channel formation above 17.0 GPa.The results in this study open a new route to construct the crystalline carbon materials with different transport properties.
基金supported by the National Defense Foundation of China(2019-JCJQ-JJ-081)the Youth Talent Lifting Project of the China Association for Science and Technology(17-JCJQ-QT-003)+1 种基金the Key Program of Natural Science Foundation of Shaanxi Province(2020JZ-33)the Key Principal’s Fund of Air Force Engineering University(XNLX19030601).
文摘Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in an on-demand manner.Recently,kirigami technique,affording versatile and unconventional structural transformation,has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner.Here,we report for a kirigami-inspired sparse meta-architecture,with structural density of 1.5%in terms of the occupation space,for adaptive invisibility based on independent operations of frequency,bandwidth,and amplitude.Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures,we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers(A,B,and C)of different geometries characterized by the folding angleβ.Our strategy circumvents issues of limited abilities,narrow tuning range,extreme condition,and high cost raised by available reconfigurable metamaterials,providing a new avenue toward multifunctional smart devices.
基金supported by the National Defense Foundation of China(2019-JCJQ-JJ-081)the Youth Talent Lifting Project of the China Association for Science and Technology(17-JCJQ-QT-003)+1 种基金the Key Program of Natural Science Foundation of Shaanxi Province(2020JZ-33)the Key Principal’s Fund of Air Force Engineering University(XNLX19030601).
文摘Many real-world applications,including adaptive radar scanning and smart stealth,require reconfigurable multifunctional devices to simultaneously manipulate multiple degrees of freedom of electromagnetic(EM)waves in an on-demand manner.Recently,kirigami technique,affording versatile and unconventional structural transformation,has been introduced to endow metamaterials with the capability of controlling EM waves in a reconfigurable manner.Here,we report for a kirigami-inspired sparse meta-architecture,with structural density of 1.5%in terms of the occupation space,for adaptive invisibility based on independent operations of frequency,bandwidth,and amplitude.Based on the general principle of dipolar management via structural reconstruction of kirigami-inspired meta-architectures,we demonstrate reconfigurable invisibility management with abundant EM functions and a wide tuning range using three enantiomers(A,B,and C)of different geometries characterized by the folding angleβ.Our strategy circumvents issues of limited abilities,narrow tuning range,extreme condition,and high cost raised by available reconfigurable metamaterials,providing a new avenue toward multifunctional smart devices.
