The ionic transport in sub-nanochannels plays a key role in energy storage,yet suffers from a high energy barrier.Wetting sub-nanochannels is crucial to accelerate ionic transport,but the introduction of water is chal...The ionic transport in sub-nanochannels plays a key role in energy storage,yet suffers from a high energy barrier.Wetting sub-nanochannels is crucial to accelerate ionic transport,but the introduction of water is challenging because of the hydrophobic extreme confinement.We propose wetting the channels by the exothermic hydration process of pre-intercalated ions,the effect of which varies distinctly with different ionic hydration structures and energies.Compared to the failed pre-intercalation of SO_(4)^(2-),HSO_(4)^(-) with weak hydration energy results in a marginal effect on the HOMO(Highest Occupied Molecular Orbital)level of water to avoid water splitting during the electrochemical intercalation.Meanwhile,the ability of water introduction is reserved by the initial incomplete dissociation state of HSO_(4)^(-),so the consequent exothermic reionization and hydration processes of the intercalated HSO_(4)^(-) promote the water introduction into sub-nanochannels,finally forming the stable confined water through hydrogen bonding with functional groups.The wetted channels exhibit a significantly enhanced ionic diffusion coef-ficient by~9.4 times.展开更多
Tellurene, an emerging two-dimensional chain-like semiconductor, stands out for its high switch ratio, carrier mobility and excellent stability in air. Directly contacting the 2D semiconductor materials with metal ele...Tellurene, an emerging two-dimensional chain-like semiconductor, stands out for its high switch ratio, carrier mobility and excellent stability in air. Directly contacting the 2D semiconductor materials with metal electrodes is a feasible doping means to inject carriers. However, Schottky barrier often arises at the metal–semiconductors interface, impeding the transport of carriers. Herein, we investigate the interfacial properties of BL tellurene by contacting with various metals including graphene by using ab initio calculations and quantum transport simulations. Vertical Schottky barriers take place in Ag, Al, Au and Cu electrodes according to the maintenance of the noncontact tellurene layer band structure. Besides, a p-type vertical Schottky contact is formed due to the van der Waals interaction for graphene electrode. As for the lateral direction, p-type Schottky contacts take shape for bulk metal electrodes(hole Schottky barrier heights(SBHs) ranging from 0.19 to 0.35 eV). Strong Fermi level pinning takes place with a pinning factor of 0.02. Notably, a desirable p-type quasi-Ohmic contact is developed for graphene electrode with a hole SBH of 0.08 eV. Our work sheds light on the interfacial properties of BL tellurene based transistors and could guide the experimental selections on electrodes.展开更多
It was recently noted that in certain nonmagnetic centrosymmetric compounds,spin–orbit interactions couple each local sector that lacks inversion symmetry,leading to visible spin polarization effects in the real spac...It was recently noted that in certain nonmagnetic centrosymmetric compounds,spin–orbit interactions couple each local sector that lacks inversion symmetry,leading to visible spin polarization effects in the real space,dubbed“hidden spin polarization(HSP)”.However,observable spin polarization of a given local sector suffers interference from its inversion partner,impeding material realization and potential applications of HSP.Starting from a single-orbital tight-binding model,we propose a nontrivial way to obtain strong sector-projected spin texture through the vanishing hybridization between inversion partners protected by nonsymmorphic symmetry.The HSP effect is generally compensated by inversion partners near the Г point but immune from the hopping effect around the boundary of the Brillouin zone.We further summarize 17 layer groups that support such symmetry-assisted HSP and identify hundreds of quasi-2D materials from the existing databases by first-principle calculations,among which a group of rare-earth compounds LnIO(Ln=Pr,Nd,Ho,Tm,and Lu)serves as great candidates showing strong Rashba-and Dresselhaus-type HSP.Our findings expand the material pool for potential spintronic applications and shed light on controlling HSP properties for emergent quantum phenomena.展开更多
New approaches are required to prevent the plagues of locusts that threaten crop security in many areas of the world. One such approach is to exploit the phototactic response of locusts, enabling their aggregation and...New approaches are required to prevent the plagues of locusts that threaten crop security in many areas of the world. One such approach is to exploit the phototactic response of locusts, enabling their aggregation and effective removal from agricultural sites. This study examined the effect of the dorsal rim area (DRA) of the locust compound eye on the phototactic response of locusts to spectral light. Locusts with intact DRA showed increased phototactic responses to blue, green or orange light but decreased responses to UV and violet light, whereas locusts with blacked-out DRA (non-DRA vision) showed the strongest phototactic responses to orange followed by violet light. The combined results revealed that phototactic push-pull effect triggered by responses of DRA versus non-DRA vision was strongest in response to violet light. Compound vision in the locust is the result of the synergism between DRA versus non-DRA vision, causing a push-pull phototactic effect that is most stimulated by exposure to violet light, with light intensity enhancing this effect. These results provide theoretical support for the induction of phototaxis and polarotaxis in response to light in locusts, which could be useful for the development of light-based control systems in the field.展开更多
This study investigated the influence of different linearly polarized spectrum lights on locusts polartactic response characteristics linearly polarized vector sensitivity mode and polartactic response by using linear...This study investigated the influence of different linearly polarized spectrum lights on locusts polartactic response characteristics linearly polarized vector sensitivity mode and polartactic response by using linearly polarized spectrum vector light module and experimental device.The objective was to clarify the vector sensitivity characteristics and functional effect of linearly polarized light spectrum intensity on locusts polartactic response,determine the influence specificity of linearly polarized spectrum illumination properties on locusts polarization-related behavior.When spectrum and illumination were constant,locusts polartactic response,presenting the response feature of sine and cosine function change specificity,was related to spectrum attribute.The visual acuity effect stimulated by violet spectrum was the best,whereas the optical distance modulation effect induced by orange spectrum was the strongest.When illumination was enhanced,locusts vector sensitivity mode shifted to present the specific sensitivity prompted by light intensity at long distance and inhibited by light intensity at short distance.Moreover,the regulating function of violet spectrum was the strongest,and the regulatory mutation effect of orange spectrum was the least significant.Simultaneously,locusts polartactic sensitivity to 300°vector at 100 lx,whereas to 240°vector at 1000 lx of linearly polarized violet light was the strongest.Locusts polartactic aggregation and visual tendency sensitivity to 90°vector at 100 lx,whereas to 270°vector at 1000 lx of linearly polarized violet light was the strongest.The heterogeneous regulation function of different linearly polarized spectrum couplings with light intensity led to significant variations in locusts vector sensitivity mode.This was derived from the antagonistic and specific tuning characteristics of locusts polartactic vision,reflecting the integrated output effect of locusts vector dependence regulated by linearly polarized spectrum intensity attribute.The findings were significant for the construction of pest polarization induction light sources and the investigation of the sensitive physiology pathway of locusts polarization vision.展开更多
To clarify the influence of yellow,green,and proportional yellow-green light on the capture effect,western flower thrips,Frankliniella occidentalis(Pergande),were captured using different self-made light sources in a ...To clarify the influence of yellow,green,and proportional yellow-green light on the capture effect,western flower thrips,Frankliniella occidentalis(Pergande),were captured using different self-made light sources in a greenhouse.The bio-activity capture effect of thrips was regulated by light and analyzed to determine the reasons for the changes in their capture by light.The results showed that the thrips’capture effect induced by different light sources with the same brightness was positively correlated with night temperature.When the average night temperature was 27℃(19:00-21:30),the capture effect was optimal,indicating that the coupling effect of light temperature can regulate the capture effect of thrips.Green light intensified and yellow light inhibited the visual trend sensitivity of thrips to yellow-green light of differing proportions.The capture effect trapped by a green-yellow light ratio of 4:1 was optimal(1088.00 individuals in night time),while that of yellow light was the worst(456.67 individuals/night),thus,indicating that visual trend sensitivity of thrips to green light was higher than that of yellow light.Such differences originated from the differences in the photoelectric thermal conversion effect of spectral optical properties,and the spectral photo-thermal effect was the main reason that thrips produced a light-trapped behavior.Night light enhanced the sensitivity of thrips’responses to a white adhesive board during the daytime,and the effect of yellow light intensity was the strongest(1563.00 individuals in the daytime),while that of green light was the weakest(75.33 individuals in the day time).Additionally,yellow light intensified while green light inhibited the regulatory effect of different proportions of yellow-green light on the bio-activity of thrips.However,the capture effect of day and night corresponding to 4:1 green-yellow light was the best(2019.67 individuals in day and night).The function of the photo-thermal effect on the capture effect of thrips was affected by the decrease in night temperature,but the photo-electro-thermal effects of night light intensified the bio-activity of thrips in the daytime and enhanced their color sensitivity.The results provide a theoretical basis for the development of pest light induction equipment.展开更多
Topological states of matter possess bulk electronic structures categorized by topological invariants and edge/surface states due to the bulk-boundary correspondence. Topological materials hold great potential in the ...Topological states of matter possess bulk electronic structures categorized by topological invariants and edge/surface states due to the bulk-boundary correspondence. Topological materials hold great potential in the development of dissipationless spintronics, information storage and quantum computation, particularly if combined with magnetic order intrinsically or extrinsically. Here, we review the recent progress in the exploration of intrinsic magnetic topological materials, including but not limited to magnetic topological insulators, magnetic topological metals, and magnetic Weyl semimetals. We pay special attention to their characteristic band features such as the gap of topological surface state, gapped Dirac cone induced by magnetization (either bulk or surface), Weyl nodal point/line and Fermi arc, as well as the exotic transport responses resulting from such band features. We conclude with a brief envision for experimental explorations of new physics or effects by incorporating other orders in intrinsic magnetic topological materials.展开更多
Locust and grasshopper plagues pose a serious threat to crop production in many areas worldwide.However,there is a lack of effective,quick-acting methods to control such outbreaks.Methods exploiting the phototactic re...Locust and grasshopper plagues pose a serious threat to crop production in many areas worldwide.However,there is a lack of effective,quick-acting methods to control such outbreaks.Methods exploiting the phototactic response of these insects are receiving increasing attention.The current study investigated the effect of linearly polarized and unpolarized light on locust phototactic and polarotactic responses,in particular the function of their dorsal rim area(DRA)and non-DRA visual fields.The results showed that the polarotactic function weight of DRA vision was stimulated by linearly polarized ultraviolet(UV)and violet light,the phototactic function weight was induced by blue,green,and orange light,and under linearly polarized light,the functional effect of DRA vision was strongest in response to linearly polarized violet light.Moreover,the locust visual response effect was related to spectral light attributes,with the linear polarization effect intensifying in response to the short-range vision sensitivity of non-DRA visual fields,whereas DRA vision regulated the short-range sensitivity of compound eye vision.When illumination increased,the synergistic enhancement effects of linearly polarized ultraviolet and violet light were significant,whereas the visual sensitivity was restricted significantly by linearly polarized blue,green,or orange light.Thus,non-DRA vision determined,while DRA vision enhanced,the phototactic response sensitivity,whereas,in linearly polarized UV or violet light,non-DRA vision determined,while DRA vision enhanced,the visual trend and polarotaxic aggregation sensitivity,with opposite effects in linearly polarized blue,green,or orange light.When illumination increased,there was a driving effect caused by linearly polarized violet light on non-DRA vision,whereas at short-wave lengths,the control effect induced by linearly polarized orange light was optimal;however,the photo-induced effect of linearly polarized violet light and the visual distance control effect of linearly polarized orange light were optimal.These results provide theoretical support for the photo-induced mechanism of the locust visual response effect and for the development of linearly polarized light sources for the environmentally friendly prevention and control of locust populations.展开更多
Anomalous Nernst effect generates a transverse voltage perpendicular to the temperature gradient.It has several advantages compared with the longitudinal thermoelectricity for energy conversion,such as decoupling of e...Anomalous Nernst effect generates a transverse voltage perpendicular to the temperature gradient.It has several advantages compared with the longitudinal thermoelectricity for energy conversion,such as decoupling of electronic and thermal transports,higher flexibility,and simpler lateral structure.However,a design principle beyond specific materials systems for obtaining a large anomalous Nernst conductivity(ANC)is still absent.In this work,we theoretically demonstrate that a pair of Dirac nodes under a Zeeman field manifests an odd-distributed,double-peak anomalous Hall conductivity curve with respect to the chemical potential and a compensated carrier feature,leading to an enhanced ANC compared with that of a simple Weyl semimetal with two Weyl nodes.Based on first-principles calculations,we then provide two Dirac semimetal candidates,i.e.,Na3Bi and NaTeAu,and show that under a Zeeman field,they exhibit a sizable ANC value of 0.4 Am^(-1)K^(-1) and 1.3 Am^(-1)K^(-1),respectively,near the Fermi level.Such an approach is also applicable to ferromagnetic materials with intrinsic Zeeman splitting,as exemplified by a hypothetical alloy NaFeTe2Au2,exhibiting an ANC as high as 3.7 Am^(-1)K^(-1) at the Fermi level.Our work provides a design principle with a prototype band structure for enhanced ANC pinning at the Fermi level,shedding light on the inverse design of other specific functional materials based on electronic structure.展开更多
To reveal the nature of locusts’visual reaction when stimulated by light,and to clarify the regulation characteristics of locusts’phototactic visual physiology and obtain good spectral light features for locusts’ph...To reveal the nature of locusts’visual reaction when stimulated by light,and to clarify the regulation characteristics of locusts’phototactic visual physiology and obtain good spectral light features for locusts’phototactic action,this study investigated locusts’visual spectrum response by characterizing their photoreceptive reaction to LED light using an AvaSpec fiber-optic spectrometer system.Locusts’phototactic response to spectral light was compared using this system.The results showed that locusts’visual reaction characterization presents a photo-induced vision spectrum effect and that by offsetting the main wavelength of light and the spectral peak intensity,a time-varying bio-regulation effect emerges.In addition,locusts’visual regulation ability to UV light is higher than that to violet light,whereas their reaction intensity is lower than to violet light,and the visual bio-regulatory force of locusts’visual system absorbing orange light to react sensitively becomes gradually higher than when absorbing green light as time goes on.Moreover,corresponding to nominal illumination with the same radiant energy and a visual spectrum response stimulated by UV,violet,orange,and green light,it appears that the visual spectrum window is symmetrical around 382 nm,400 nm,602 nm,and 530 nm,respectively,with no significant difference between spectral amplitudes and having a time-varying incremental characteristic with amplitude peak width.This indicates that the stimulus intensity of UV,violet,orange,and green light exceeds locusts’visual tolerance,causing them to generate regulation inactivation as a visual physiological reaction,whereas the visual window response effect stimulated by UV light presents an illumination timeliness effect.Simultaneously,time-varying characteristics of locusts’bio-behavior intensity show that light intensity can make up for locusts’visual sensitivity differences at various spectral wavelengths.Presented with differential response time,photosensitive behavior intensity,and induction effect induced by orange light,time is superior for orange light,the stimulation effect caused by violet light is the strongest,and the phototactic synergy effect caused by UV light is the best.展开更多
MoS2 has emerged for catalyzing the hydrogen evolution reaction.Various notable strategies have been developed to downsize the MoS2 particles and expose more active edges.However,the restacking issue,which reduces the...MoS2 has emerged for catalyzing the hydrogen evolution reaction.Various notable strategies have been developed to downsize the MoS2 particles and expose more active edges.However,the restacking issue,which reduces the exposure degree,has rarely been taken into account.Herein,we report on a facile proton-induced fast hydrothermal approach to produce size-controllable MoS2 nanocatalysts and demonstrate that along the varying of sheet sizes,there is a trade-off between the intrinsic catalytic activity(mainly determined by the unsaturated sulfur on the sheet edges)and the active edge accessibility(influenced by the assembly structure).The size-optimized catalyst delivers a high performance of a low overpotential of~200 mV at 10 mA/cm^(2),a Tafel slope of 46.3 mV/dec,and a stable working state,which is comparable to the recent notable works.Our findings will provide a pathway for its large-scale application and enhance the water electrolysis performance.展开更多
This study aimed to determine the effects of spectral light characteristics on the visual response of the western flower thrips,the strengthening mechanism of thrips response behavior regulated by light,and thrips res...This study aimed to determine the effects of spectral light characteristics on the visual response of the western flower thrips,the strengthening mechanism of thrips response behavior regulated by light,and thrips response characteristics to contrast light.Light with combined and single wavelength were tested by using a self-made behavior response device for thrips.Light sources for trapping thrips were made to verify the trapping effect on thrips in a greenhouse,and the reasons for changes in thrips behavior were analyzed to characterize the mechanism of their phototactic response.The results showed that the light mode(single,contrast,combined light)affected the thrips visual response and approach response,whereas in contrast light,the effects were optimal.Combination light inhibited the thrips visual response,and when the illumination increased,the thrips visual response to single and combination light intensified,and the thrips approach sensitivity to green light increased in contrast and combination light.However,the light mode did not affect the thrips visual response and sensitivity to spectral light characteristics.The degree of thrips visual response to yellow light was stronger than that to green light,while the degree of thrips visual response to green light was stronger than that to yellow light,indicating that the photo-induced mechanism of the thrips visual response differed from that of the thrips approach response.Moreover,in the greenhouse,the trapping effect of different light sources on thrips was positively correlated with temperature.The trapping effect of green light was optimal,followed by a yellow light source,while the difference of light intensity(illumination,illumination energy)and its photo-thermal intensity between yellow and green light was the reason for the differences in the degree of visual trends and the trapping effects of thrips.However,the sensitivity of thrips responding to different light depended on the difference in the heterogeneous stimulation intensity of different spectral light.Thus,light brightness and photo-thermal effects were the causes of thrips visual responses,while bio-photoelectric reaction effects caused thrips to produce a visual response and affected the degree of the thrips visual response.The results reveal the underlying causes of pest control by light,and provide a theoretical basis for the research and development of pest induction equipment and light arrangements.展开更多
To understand how spectral light wavelength affects thrips visual sensitivity,the selective response and the approach sensitivity of western flower thrips were examined.The results showed that light intensity affected...To understand how spectral light wavelength affects thrips visual sensitivity,the selective response and the approach sensitivity of western flower thrips were examined.The results showed that light intensity affected thrips selective sensitivity to different spectra,with good visual sensitivity to blue,ultraviolet(UV),and green light changes to UV,violet,and yellow light when illumination increased from 120 lx to 6000 lx.Red light was the sensitive spectral light driving thrips to respond to sensitive light.Under illumination,the best sensitivity response to spectra was violet,while under light energy,this changed to UV when light energy was increased to 120 mW/cm^(2).However,the photo-stimulus properties(illumination or light energy)did not affect the optimal approach sensitivity to UV light.Furthermore,when illumination or light energy stimulated thrips to select two different spectral lights,the total response sensitivity to 12000 lx of UV and violet light were the best(83.27%),while at 60 mW/cm^(2) of UV and yellow light was the best(82.15%).But different photo-stimulus properties influenced on the total approach sensitivity to the stimulation of two different spectral lights when the intensity of light increased,showing that to 12000 lx of violet and green light was the best(53.18%),while for 120 mW/cm^(2) of UV and green light was the best(47.74%).The thrips visual selection response effects stimulated by illumination were different from that induced by light energy,and originated from the thrips different bio-regulatory effects caused by the intensity of light energy of illumination and the intensity of illumination of light energy.Therefore,different photo-stimulus effects can manipulate thrips visual sensitivity to enhance the phototactic effect.展开更多
This study aimed to clarify the synergistic phototactic attraction-repulsion effect formed by the photo-induced approach-avoidance behavior of thrips,construct phototactic attraction-repulsion light control technologi...This study aimed to clarify the synergistic phototactic attraction-repulsion effect formed by the photo-induced approach-avoidance behavior of thrips,construct phototactic attraction-repulsion light control technologies.The phototactic push-pull effects of red light and UV(365 nm),violet(405 nm),green(520 nm),and yellow(560 nm)single light,as well as their pairwise combined light on the behavior of western flower thrips were investigated using an apparatus that measured thrips response.The study also analyzed the influence of light properties on the phototactic attraction-repulsion effects of thrips and the synergistic effects of red light,and the attraction-repulsion regulation mode.The influence factors on the photo-induced attraction-repulsion effect of thrips were also discussed.The results showed that the red light,presenting the push effect,drove thrips to respond to the sensitive light.The synergistic attraction-repulsion effect of red light and singlelight,as well as that of red light and combined light was related to the light intensity.However,the attraction-repulsion synergism did not reflect thrips response effect and approach effect pulled and pushed by red light and single light,red light and combined light.Thrips preference for green-yellow light,and their behavior depended on the degree of UV light,making the attraction-repulsion synergy of red and green light the strongest.When the light intensity increased,the attraction-repulsion synergy of red and yellow light was the strongest.The attraction-repulsion response to red light and single light was related to the spectral attribute of the single light,with that of red lightand UV light being better.The attraction-repulsion response to red light and combined light was related to light intensity.The intensity of combined light made the attraction-repulsion response to red light and the combined UV and violet light be the best,and the brightness of long-short spectrum light rendered red light and the combined UV and yellow light the best.All such light and combinations were remarkably better than that of red light and UV light.Relative to red light and UV light,the use ofred light and combined light provided limited enhancement to the approach effect of thrips;however,under red light and combined light,violet light intensified the approach of thrips to UV light,with yellow light strengthening the approach to green light.Those results provided a scientific basis for the development of light trapping equipment and the adjustment of light control strategies for thrips.展开更多
In this paper,we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range.In the proposed novel porous metamaterial struc...In this paper,we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range.In the proposed novel porous metamaterial structure,a porous material matrix containing periodically perforated cylindrical holes arranged in a triangular lattice pattern is applied,and additional interlayers of another porous material are introduced around these perforations.The theoretical model is established by adopting the double porosity theory for the interlayer and the cylindrical hole which form an equivalent inclusion and then applying the homogenization method to the porous metamaterial structure formed by the equivalent inclusion and the porous matrix.The temperature-dependent air and material parameters are considered in the extended theoretical model,which is validated by the finite element results obtained by COMSOL Multiphysics.The acoustic or sound energy absorption performance can be improved remarkably at very low frequencies and high temperature.Furthermore,the underlying acoustic energy absorption mechanism inside the unit-cell is investigated by analyzing the distribution of the time-averaged acoustic power dissipation density and the energy dissipation ratio of each constituent porous material.The results reveal that regardless of the temperature,the acoustic energy is mostly dissipated in the porous material with a lower airflow resistivity,while the acoustic energy dissipated in the porous material with a higher airflow resistivity also becomes considerable in the high-frequency range.The novel porous metamaterial structure proposed in this paper can be efficiently utilized to improve the acoustic energy absorption performance at high temperature.展开更多
Aqueous rechargeable Ni−Zn batteries are considered as a new generation of safe and reliable electro-chemical energy storage system.However,low electronic conductivity of Ni-based cathodes hinders the practical applic...Aqueous rechargeable Ni−Zn batteries are considered as a new generation of safe and reliable electro-chemical energy storage system.However,low electronic conductivity of Ni-based cathodes hinders the practical application of Ni-Zn batteries.This problem can be overcome by compositing the Ni-based cath-ode with highly conductive carbon substrates.A chemical oxidation pre-treatment is popularly applied to the carbon substrates to increase their hydrophilicity and thus facilitate the growth of active materials in aqueous systems.However,the anodic stability of the oxidized carbon substrates is greatly challenged,which has never been addressed in previous reports.In this work,we first compared the anodic stabil-ity of carbon fiber paper with and without oxidation treatment and find that carbon substrate with the chemical treatment caused remarkable oxidization current in the required voltage range.To take both anodic stability and fine growth of active materials into account,here we demonstrated a facile physical surface-treatment method of ethanol wetting to replace the chemical treatment.The ethanol infiltration removes gas adsorption on carbon substrates and thus promotes their hydrophilicity.This cost-effective strategy simultaneously achieves a high anodic stability and a fine growth and uniform distribution of nickel-cobalt hydroxide on the carbon microfibers.The resulting Ni-Zn battery provides a high discharge capacity of 219 mAh/g with an operation cell voltage of 1.75 V.展开更多
Dirac semimetal is a phase of matter whose elementary excitation is described by the relativistic Dirac equation.In the limit of zero mass,its parity-time symmetry enforces the Dirac fermion in the momentum space,whic...Dirac semimetal is a phase of matter whose elementary excitation is described by the relativistic Dirac equation.In the limit of zero mass,its parity-time symmetry enforces the Dirac fermion in the momentum space,which is composed of two Weyl fermions with opposite chirality,to be non-chiral.Inspired by the flavor symmetry in particle physics,we theoretically propose a massless Dirac-like equation yet linking two Weyl fields with the identical chirality by assuming SUe2T isospin symmetry,independent of the space-time rotation exchanging the two fields.Dramatically,such symmetry is hidden in certain solid-state spin-1/2 systems with negligible spinorbit coupling,where the spin degree of freedom is decoupled with the lattice.Therefore,the existence of the corresponding quasiparticle,dubbed as flavor Weyl fermion,cannot be explained by the conventional(magnetic)space group framework.The 4-fold degenerate flavor Weyl fermion manifests linear dispersion and a Chern number of±2,leading to a robust network of topologically protected Fermi arcs throughout the Brillouin zone.For material realization,we show that the transition-metal chalcogenide CoNb3S6 with experimentally confirmed collinear antiferromagnetic order is ideal for flavor Weyl semimetal under the approximation of vanishing spin-orbit coupling.Our work reveals a counterpart of the flavor symmetry in magnetic electronic systems,leading to further possibilities of emergent phenomena in quantum materials.展开更多
基金supported by the National Key Research and Development Program of China(2021YFA1101300)the National Natural Science Foundation of China(Grant No.22225801,21776197,22078214,and 21905206)Special Fund for Science and Technology Innovation Team of Shanxi Province(No.202204051001009).
文摘The ionic transport in sub-nanochannels plays a key role in energy storage,yet suffers from a high energy barrier.Wetting sub-nanochannels is crucial to accelerate ionic transport,but the introduction of water is challenging because of the hydrophobic extreme confinement.We propose wetting the channels by the exothermic hydration process of pre-intercalated ions,the effect of which varies distinctly with different ionic hydration structures and energies.Compared to the failed pre-intercalation of SO_(4)^(2-),HSO_(4)^(-) with weak hydration energy results in a marginal effect on the HOMO(Highest Occupied Molecular Orbital)level of water to avoid water splitting during the electrochemical intercalation.Meanwhile,the ability of water introduction is reserved by the initial incomplete dissociation state of HSO_(4)^(-),so the consequent exothermic reionization and hydration processes of the intercalated HSO_(4)^(-) promote the water introduction into sub-nanochannels,finally forming the stable confined water through hydrogen bonding with functional groups.The wetted channels exhibit a significantly enhanced ionic diffusion coef-ficient by~9.4 times.
基金supported by the National Natural Science Foundation of China(Nos.11674005,11664026,11704406)the National Materials Genome Project of China(No2016YFB0700600)+4 种基金the Key Research and Development Program of Ningxia(No.2018BEE03023)the Natural Science Foundation of Ningxia(No.2018AAC03236)the Higher Schoo Scientific Research Project of Ningxia Department of Education(No.NGY2018-130)the Key Scientific Research Project of Ningxia Normal University(No.NXSFZDA1807)the Youth Talent Support Program of Ningxia,China(2016)
文摘Tellurene, an emerging two-dimensional chain-like semiconductor, stands out for its high switch ratio, carrier mobility and excellent stability in air. Directly contacting the 2D semiconductor materials with metal electrodes is a feasible doping means to inject carriers. However, Schottky barrier often arises at the metal–semiconductors interface, impeding the transport of carriers. Herein, we investigate the interfacial properties of BL tellurene by contacting with various metals including graphene by using ab initio calculations and quantum transport simulations. Vertical Schottky barriers take place in Ag, Al, Au and Cu electrodes according to the maintenance of the noncontact tellurene layer band structure. Besides, a p-type vertical Schottky contact is formed due to the van der Waals interaction for graphene electrode. As for the lateral direction, p-type Schottky contacts take shape for bulk metal electrodes(hole Schottky barrier heights(SBHs) ranging from 0.19 to 0.35 eV). Strong Fermi level pinning takes place with a pinning factor of 0.02. Notably, a desirable p-type quasi-Ohmic contact is developed for graphene electrode with a hole SBH of 0.08 eV. Our work sheds light on the interfacial properties of BL tellurene based transistors and could guide the experimental selections on electrodes.
基金National Natural Science Foundation of China(Grant No.11874195)the Guangdong Provincial Key Laboratory of Computational Science and Material Design(Grant No.2019B030301001)the Center for Computational Science and Engineering of SUSTech.
文摘It was recently noted that in certain nonmagnetic centrosymmetric compounds,spin–orbit interactions couple each local sector that lacks inversion symmetry,leading to visible spin polarization effects in the real space,dubbed“hidden spin polarization(HSP)”.However,observable spin polarization of a given local sector suffers interference from its inversion partner,impeding material realization and potential applications of HSP.Starting from a single-orbital tight-binding model,we propose a nontrivial way to obtain strong sector-projected spin texture through the vanishing hybridization between inversion partners protected by nonsymmorphic symmetry.The HSP effect is generally compensated by inversion partners near the Г point but immune from the hopping effect around the boundary of the Brillouin zone.We further summarize 17 layer groups that support such symmetry-assisted HSP and identify hundreds of quasi-2D materials from the existing databases by first-principle calculations,among which a group of rare-earth compounds LnIO(Ln=Pr,Nd,Ho,Tm,and Lu)serves as great candidates showing strong Rashba-and Dresselhaus-type HSP.Our findings expand the material pool for potential spintronic applications and shed light on controlling HSP properties for emergent quantum phenomena.
基金supported by the Scientific and Technological Project of Henan Province,China(Grant No.242102111179,222102210116,222102320080)the Natural Science Foundation Project of Henan Province,China(Grant No.232300420024)the National Natural Science Foundation of China(Grant No.31772501).
文摘New approaches are required to prevent the plagues of locusts that threaten crop security in many areas of the world. One such approach is to exploit the phototactic response of locusts, enabling their aggregation and effective removal from agricultural sites. This study examined the effect of the dorsal rim area (DRA) of the locust compound eye on the phototactic response of locusts to spectral light. Locusts with intact DRA showed increased phototactic responses to blue, green or orange light but decreased responses to UV and violet light, whereas locusts with blacked-out DRA (non-DRA vision) showed the strongest phototactic responses to orange followed by violet light. The combined results revealed that phototactic push-pull effect triggered by responses of DRA versus non-DRA vision was strongest in response to violet light. Compound vision in the locust is the result of the synergism between DRA versus non-DRA vision, causing a push-pull phototactic effect that is most stimulated by exposure to violet light, with light intensity enhancing this effect. These results provide theoretical support for the induction of phototaxis and polarotaxis in response to light in locusts, which could be useful for the development of light-based control systems in the field.
基金financially supported by the Scientific and Technological Project of Henan Province,China(Grant No.242102111179,222102210116,222102320080)the Science and Technology Opening Cooperation Project of Henan,China(Grant No.172106000056)the National Natural Science Foundation of China(Grant No.31772501).
文摘This study investigated the influence of different linearly polarized spectrum lights on locusts polartactic response characteristics linearly polarized vector sensitivity mode and polartactic response by using linearly polarized spectrum vector light module and experimental device.The objective was to clarify the vector sensitivity characteristics and functional effect of linearly polarized light spectrum intensity on locusts polartactic response,determine the influence specificity of linearly polarized spectrum illumination properties on locusts polarization-related behavior.When spectrum and illumination were constant,locusts polartactic response,presenting the response feature of sine and cosine function change specificity,was related to spectrum attribute.The visual acuity effect stimulated by violet spectrum was the best,whereas the optical distance modulation effect induced by orange spectrum was the strongest.When illumination was enhanced,locusts vector sensitivity mode shifted to present the specific sensitivity prompted by light intensity at long distance and inhibited by light intensity at short distance.Moreover,the regulating function of violet spectrum was the strongest,and the regulatory mutation effect of orange spectrum was the least significant.Simultaneously,locusts polartactic sensitivity to 300°vector at 100 lx,whereas to 240°vector at 1000 lx of linearly polarized violet light was the strongest.Locusts polartactic aggregation and visual tendency sensitivity to 90°vector at 100 lx,whereas to 270°vector at 1000 lx of linearly polarized violet light was the strongest.The heterogeneous regulation function of different linearly polarized spectrum couplings with light intensity led to significant variations in locusts vector sensitivity mode.This was derived from the antagonistic and specific tuning characteristics of locusts polartactic vision,reflecting the integrated output effect of locusts vector dependence regulated by linearly polarized spectrum intensity attribute.The findings were significant for the construction of pest polarization induction light sources and the investigation of the sensitive physiology pathway of locusts polarization vision.
基金supported by the Scientific and technological project in Henan Province,China(Grant No.212102110139,212102110229)the Special Project of Xinxiang Science and Technology,China(Grant No.21ZD003)the Agriculture Research System of MOF and MARA(Grant No.CARS-03).
文摘To clarify the influence of yellow,green,and proportional yellow-green light on the capture effect,western flower thrips,Frankliniella occidentalis(Pergande),were captured using different self-made light sources in a greenhouse.The bio-activity capture effect of thrips was regulated by light and analyzed to determine the reasons for the changes in their capture by light.The results showed that the thrips’capture effect induced by different light sources with the same brightness was positively correlated with night temperature.When the average night temperature was 27℃(19:00-21:30),the capture effect was optimal,indicating that the coupling effect of light temperature can regulate the capture effect of thrips.Green light intensified and yellow light inhibited the visual trend sensitivity of thrips to yellow-green light of differing proportions.The capture effect trapped by a green-yellow light ratio of 4:1 was optimal(1088.00 individuals in night time),while that of yellow light was the worst(456.67 individuals/night),thus,indicating that visual trend sensitivity of thrips to green light was higher than that of yellow light.Such differences originated from the differences in the photoelectric thermal conversion effect of spectral optical properties,and the spectral photo-thermal effect was the main reason that thrips produced a light-trapped behavior.Night light enhanced the sensitivity of thrips’responses to a white adhesive board during the daytime,and the effect of yellow light intensity was the strongest(1563.00 individuals in the daytime),while that of green light was the weakest(75.33 individuals in the day time).Additionally,yellow light intensified while green light inhibited the regulatory effect of different proportions of yellow-green light on the bio-activity of thrips.However,the capture effect of day and night corresponding to 4:1 green-yellow light was the best(2019.67 individuals in day and night).The function of the photo-thermal effect on the capture effect of thrips was affected by the decrease in night temperature,but the photo-electro-thermal effects of night light intensified the bio-activity of thrips in the daytime and enhanced their color sensitivity.The results provide a theoretical basis for the development of pest light induction equipment.
基金This work was supported by the National Key R&D Program of China(Grant Nos.2022YFA1403700 and 2020YFA0308900)the National Natural Science Foundation of China(NSFC)(Grant Nos.12074163,12074161,and 11504159)+3 种基金NSFC Guangdong(No.2016A030313650)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022B1515020046,2022B1515130005 and 2021B1515130007)the Guangdong Innovative and Entrepreneurial Research Team Program(Grant Nos.2019ZT08C044 and 2016ZT06D348)Shenzhen Science and Technology Program(Grant No.KQTD20190929173815000).
文摘Topological states of matter possess bulk electronic structures categorized by topological invariants and edge/surface states due to the bulk-boundary correspondence. Topological materials hold great potential in the development of dissipationless spintronics, information storage and quantum computation, particularly if combined with magnetic order intrinsically or extrinsically. Here, we review the recent progress in the exploration of intrinsic magnetic topological materials, including but not limited to magnetic topological insulators, magnetic topological metals, and magnetic Weyl semimetals. We pay special attention to their characteristic band features such as the gap of topological surface state, gapped Dirac cone induced by magnetization (either bulk or surface), Weyl nodal point/line and Fermi arc, as well as the exotic transport responses resulting from such band features. We conclude with a brief envision for experimental explorations of new physics or effects by incorporating other orders in intrinsic magnetic topological materials.
基金The authors acknowledge that this work was financially supported by the Scientific and Technological Project of Henan Province,China(Grant No.222102210116,212102110229)the special project of Xinxiang Science and Technology of Henan Province,China(Grant No.21ZD003)the National Natural Science Foundation of China(Grant No.31772501).
文摘Locust and grasshopper plagues pose a serious threat to crop production in many areas worldwide.However,there is a lack of effective,quick-acting methods to control such outbreaks.Methods exploiting the phototactic response of these insects are receiving increasing attention.The current study investigated the effect of linearly polarized and unpolarized light on locust phototactic and polarotactic responses,in particular the function of their dorsal rim area(DRA)and non-DRA visual fields.The results showed that the polarotactic function weight of DRA vision was stimulated by linearly polarized ultraviolet(UV)and violet light,the phototactic function weight was induced by blue,green,and orange light,and under linearly polarized light,the functional effect of DRA vision was strongest in response to linearly polarized violet light.Moreover,the locust visual response effect was related to spectral light attributes,with the linear polarization effect intensifying in response to the short-range vision sensitivity of non-DRA visual fields,whereas DRA vision regulated the short-range sensitivity of compound eye vision.When illumination increased,the synergistic enhancement effects of linearly polarized ultraviolet and violet light were significant,whereas the visual sensitivity was restricted significantly by linearly polarized blue,green,or orange light.Thus,non-DRA vision determined,while DRA vision enhanced,the phototactic response sensitivity,whereas,in linearly polarized UV or violet light,non-DRA vision determined,while DRA vision enhanced,the visual trend and polarotaxic aggregation sensitivity,with opposite effects in linearly polarized blue,green,or orange light.When illumination increased,there was a driving effect caused by linearly polarized violet light on non-DRA vision,whereas at short-wave lengths,the control effect induced by linearly polarized orange light was optimal;however,the photo-induced effect of linearly polarized violet light and the visual distance control effect of linearly polarized orange light were optimal.These results provide theoretical support for the photo-induced mechanism of the locust visual response effect and for the development of linearly polarized light sources for the environmentally friendly prevention and control of locust populations.
基金This work was supported by the National Key R&D Program of China under Grant No.2019YFA0704900Guangdong Provincial Key Laboratory for Computational Science and Material Design under Grant No.2019B030301001+2 种基金the Science,Technology and Innovation Commission of Shenzhen Municipality(No.ZDSYS20190902092905285)Center for Computational Science and Engineering of Southern University of Science and TechnologyX.S.W.acknowledges financial support from the National Key R&D Program of China under Grant No.2022YFA1403700 and NSFC under Grant No.12074009.
文摘Anomalous Nernst effect generates a transverse voltage perpendicular to the temperature gradient.It has several advantages compared with the longitudinal thermoelectricity for energy conversion,such as decoupling of electronic and thermal transports,higher flexibility,and simpler lateral structure.However,a design principle beyond specific materials systems for obtaining a large anomalous Nernst conductivity(ANC)is still absent.In this work,we theoretically demonstrate that a pair of Dirac nodes under a Zeeman field manifests an odd-distributed,double-peak anomalous Hall conductivity curve with respect to the chemical potential and a compensated carrier feature,leading to an enhanced ANC compared with that of a simple Weyl semimetal with two Weyl nodes.Based on first-principles calculations,we then provide two Dirac semimetal candidates,i.e.,Na3Bi and NaTeAu,and show that under a Zeeman field,they exhibit a sizable ANC value of 0.4 Am^(-1)K^(-1) and 1.3 Am^(-1)K^(-1),respectively,near the Fermi level.Such an approach is also applicable to ferromagnetic materials with intrinsic Zeeman splitting,as exemplified by a hypothetical alloy NaFeTe2Au2,exhibiting an ANC as high as 3.7 Am^(-1)K^(-1) at the Fermi level.Our work provides a design principle with a prototype band structure for enhanced ANC pinning at the Fermi level,shedding light on the inverse design of other specific functional materials based on electronic structure.
基金The authors acknowledge that this work was financially supported by the Scientific and technological project in Henan Province(Grant No.212102110139)the China Agricultural Research System(Grant No.CARS-03)the Henan Engineering Research Center of Biological Pesticide&Fertilizer Development and Synergistic Application.
文摘To reveal the nature of locusts’visual reaction when stimulated by light,and to clarify the regulation characteristics of locusts’phototactic visual physiology and obtain good spectral light features for locusts’phototactic action,this study investigated locusts’visual spectrum response by characterizing their photoreceptive reaction to LED light using an AvaSpec fiber-optic spectrometer system.Locusts’phototactic response to spectral light was compared using this system.The results showed that locusts’visual reaction characterization presents a photo-induced vision spectrum effect and that by offsetting the main wavelength of light and the spectral peak intensity,a time-varying bio-regulation effect emerges.In addition,locusts’visual regulation ability to UV light is higher than that to violet light,whereas their reaction intensity is lower than to violet light,and the visual bio-regulatory force of locusts’visual system absorbing orange light to react sensitively becomes gradually higher than when absorbing green light as time goes on.Moreover,corresponding to nominal illumination with the same radiant energy and a visual spectrum response stimulated by UV,violet,orange,and green light,it appears that the visual spectrum window is symmetrical around 382 nm,400 nm,602 nm,and 530 nm,respectively,with no significant difference between spectral amplitudes and having a time-varying incremental characteristic with amplitude peak width.This indicates that the stimulus intensity of UV,violet,orange,and green light exceeds locusts’visual tolerance,causing them to generate regulation inactivation as a visual physiological reaction,whereas the visual window response effect stimulated by UV light presents an illumination timeliness effect.Simultaneously,time-varying characteristics of locusts’bio-behavior intensity show that light intensity can make up for locusts’visual sensitivity differences at various spectral wavelengths.Presented with differential response time,photosensitive behavior intensity,and induction effect induced by orange light,time is superior for orange light,the stimulation effect caused by violet light is the strongest,and the phototactic synergy effect caused by UV light is the best.
基金supported by the National Natural Science Foundation of China(No.21905206)Shanghai Sail Program(No.19YF1450800)。
文摘MoS2 has emerged for catalyzing the hydrogen evolution reaction.Various notable strategies have been developed to downsize the MoS2 particles and expose more active edges.However,the restacking issue,which reduces the exposure degree,has rarely been taken into account.Herein,we report on a facile proton-induced fast hydrothermal approach to produce size-controllable MoS2 nanocatalysts and demonstrate that along the varying of sheet sizes,there is a trade-off between the intrinsic catalytic activity(mainly determined by the unsaturated sulfur on the sheet edges)and the active edge accessibility(influenced by the assembly structure).The size-optimized catalyst delivers a high performance of a low overpotential of~200 mV at 10 mA/cm^(2),a Tafel slope of 46.3 mV/dec,and a stable working state,which is comparable to the recent notable works.Our findings will provide a pathway for its large-scale application and enhance the water electrolysis performance.
基金The authors acknowledge that this work was financial supported by the Scientific and technological project in Henan Province(Grant No.212102110139)the China Agricultural Research System(Grant No.CARS-03).
文摘This study aimed to determine the effects of spectral light characteristics on the visual response of the western flower thrips,the strengthening mechanism of thrips response behavior regulated by light,and thrips response characteristics to contrast light.Light with combined and single wavelength were tested by using a self-made behavior response device for thrips.Light sources for trapping thrips were made to verify the trapping effect on thrips in a greenhouse,and the reasons for changes in thrips behavior were analyzed to characterize the mechanism of their phototactic response.The results showed that the light mode(single,contrast,combined light)affected the thrips visual response and approach response,whereas in contrast light,the effects were optimal.Combination light inhibited the thrips visual response,and when the illumination increased,the thrips visual response to single and combination light intensified,and the thrips approach sensitivity to green light increased in contrast and combination light.However,the light mode did not affect the thrips visual response and sensitivity to spectral light characteristics.The degree of thrips visual response to yellow light was stronger than that to green light,while the degree of thrips visual response to green light was stronger than that to yellow light,indicating that the photo-induced mechanism of the thrips visual response differed from that of the thrips approach response.Moreover,in the greenhouse,the trapping effect of different light sources on thrips was positively correlated with temperature.The trapping effect of green light was optimal,followed by a yellow light source,while the difference of light intensity(illumination,illumination energy)and its photo-thermal intensity between yellow and green light was the reason for the differences in the degree of visual trends and the trapping effects of thrips.However,the sensitivity of thrips responding to different light depended on the difference in the heterogeneous stimulation intensity of different spectral light.Thus,light brightness and photo-thermal effects were the causes of thrips visual responses,while bio-photoelectric reaction effects caused thrips to produce a visual response and affected the degree of the thrips visual response.The results reveal the underlying causes of pest control by light,and provide a theoretical basis for the research and development of pest induction equipment and light arrangements.
基金support from the Research and Development of New Anti-Moth Materials for Sub Projects of National Key R&D Projects and Evaluation of Control Effects(Grant No.2017YFD0200907)the China Agricultural Research System(Grant No.CARS-03)And Research and Application of New Trapping Technology for Thrips(Grant No.2019CY05).
文摘To understand how spectral light wavelength affects thrips visual sensitivity,the selective response and the approach sensitivity of western flower thrips were examined.The results showed that light intensity affected thrips selective sensitivity to different spectra,with good visual sensitivity to blue,ultraviolet(UV),and green light changes to UV,violet,and yellow light when illumination increased from 120 lx to 6000 lx.Red light was the sensitive spectral light driving thrips to respond to sensitive light.Under illumination,the best sensitivity response to spectra was violet,while under light energy,this changed to UV when light energy was increased to 120 mW/cm^(2).However,the photo-stimulus properties(illumination or light energy)did not affect the optimal approach sensitivity to UV light.Furthermore,when illumination or light energy stimulated thrips to select two different spectral lights,the total response sensitivity to 12000 lx of UV and violet light were the best(83.27%),while at 60 mW/cm^(2) of UV and yellow light was the best(82.15%).But different photo-stimulus properties influenced on the total approach sensitivity to the stimulation of two different spectral lights when the intensity of light increased,showing that to 12000 lx of violet and green light was the best(53.18%),while for 120 mW/cm^(2) of UV and green light was the best(47.74%).The thrips visual selection response effects stimulated by illumination were different from that induced by light energy,and originated from the thrips different bio-regulatory effects caused by the intensity of light energy of illumination and the intensity of illumination of light energy.Therefore,different photo-stimulus effects can manipulate thrips visual sensitivity to enhance the phototactic effect.
基金We acknowledge that this work was financially supported by the Scientific and Technological Project in Henan Province(Grant No.212102110139,212102110229)the special project of Xinxiang Science and Technology(Grant No.21ZD003)the Agriculture Research System of MOF and MARA(Grant No.CARS-03).
文摘This study aimed to clarify the synergistic phototactic attraction-repulsion effect formed by the photo-induced approach-avoidance behavior of thrips,construct phototactic attraction-repulsion light control technologies.The phototactic push-pull effects of red light and UV(365 nm),violet(405 nm),green(520 nm),and yellow(560 nm)single light,as well as their pairwise combined light on the behavior of western flower thrips were investigated using an apparatus that measured thrips response.The study also analyzed the influence of light properties on the phototactic attraction-repulsion effects of thrips and the synergistic effects of red light,and the attraction-repulsion regulation mode.The influence factors on the photo-induced attraction-repulsion effect of thrips were also discussed.The results showed that the red light,presenting the push effect,drove thrips to respond to the sensitive light.The synergistic attraction-repulsion effect of red light and singlelight,as well as that of red light and combined light was related to the light intensity.However,the attraction-repulsion synergism did not reflect thrips response effect and approach effect pulled and pushed by red light and single light,red light and combined light.Thrips preference for green-yellow light,and their behavior depended on the degree of UV light,making the attraction-repulsion synergy of red and green light the strongest.When the light intensity increased,the attraction-repulsion synergy of red and yellow light was the strongest.The attraction-repulsion response to red light and single light was related to the spectral attribute of the single light,with that of red lightand UV light being better.The attraction-repulsion response to red light and combined light was related to light intensity.The intensity of combined light made the attraction-repulsion response to red light and the combined UV and violet light be the best,and the brightness of long-short spectrum light rendered red light and the combined UV and yellow light the best.All such light and combinations were remarkably better than that of red light and UV light.Relative to red light and UV light,the use ofred light and combined light provided limited enhancement to the approach effect of thrips;however,under red light and combined light,violet light intensified the approach of thrips to UV light,with yellow light strengthening the approach to green light.Those results provided a scientific basis for the development of light trapping equipment and the adjustment of light control strategies for thrips.
基金the German Research Foundation(DFG,Project-No.ZH 15/32-1),which is gratefully acknowledged.
文摘In this paper,we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range.In the proposed novel porous metamaterial structure,a porous material matrix containing periodically perforated cylindrical holes arranged in a triangular lattice pattern is applied,and additional interlayers of another porous material are introduced around these perforations.The theoretical model is established by adopting the double porosity theory for the interlayer and the cylindrical hole which form an equivalent inclusion and then applying the homogenization method to the porous metamaterial structure formed by the equivalent inclusion and the porous matrix.The temperature-dependent air and material parameters are considered in the extended theoretical model,which is validated by the finite element results obtained by COMSOL Multiphysics.The acoustic or sound energy absorption performance can be improved remarkably at very low frequencies and high temperature.Furthermore,the underlying acoustic energy absorption mechanism inside the unit-cell is investigated by analyzing the distribution of the time-averaged acoustic power dissipation density and the energy dissipation ratio of each constituent porous material.The results reveal that regardless of the temperature,the acoustic energy is mostly dissipated in the porous material with a lower airflow resistivity,while the acoustic energy dissipated in the porous material with a higher airflow resistivity also becomes considerable in the high-frequency range.The novel porous metamaterial structure proposed in this paper can be efficiently utilized to improve the acoustic energy absorption performance at high temperature.
基金supported by National Natural Science Foun-dation of China(No.21905206),Shanghai Sail Program(No.19YF1450800).
文摘Aqueous rechargeable Ni−Zn batteries are considered as a new generation of safe and reliable electro-chemical energy storage system.However,low electronic conductivity of Ni-based cathodes hinders the practical application of Ni-Zn batteries.This problem can be overcome by compositing the Ni-based cath-ode with highly conductive carbon substrates.A chemical oxidation pre-treatment is popularly applied to the carbon substrates to increase their hydrophilicity and thus facilitate the growth of active materials in aqueous systems.However,the anodic stability of the oxidized carbon substrates is greatly challenged,which has never been addressed in previous reports.In this work,we first compared the anodic stabil-ity of carbon fiber paper with and without oxidation treatment and find that carbon substrate with the chemical treatment caused remarkable oxidization current in the required voltage range.To take both anodic stability and fine growth of active materials into account,here we demonstrated a facile physical surface-treatment method of ethanol wetting to replace the chemical treatment.The ethanol infiltration removes gas adsorption on carbon substrates and thus promotes their hydrophilicity.This cost-effective strategy simultaneously achieves a high anodic stability and a fine growth and uniform distribution of nickel-cobalt hydroxide on the carbon microfibers.The resulting Ni-Zn battery provides a high discharge capacity of 219 mAh/g with an operation cell voltage of 1.75 V.
基金supported by National Key R&D Program of China under Grant No.2020YFA0308900the National Natural Science Foundation of China under Grant No.11874195,Guangdong Innovative and Entrepreneurial Research TeamProgramunder Grant No.2017ZT07C062,Guangdong Provincial Key Laboratory of Computational Science and Material Design under Grant No.2019B030301001+1 种基金the Science,Technology and Innovation Commission of Shenzhen Municipality(No.ZDSYS20190902092905285)Center for Computational Science and Engineering of Southern University of Science and Technology.
文摘Dirac semimetal is a phase of matter whose elementary excitation is described by the relativistic Dirac equation.In the limit of zero mass,its parity-time symmetry enforces the Dirac fermion in the momentum space,which is composed of two Weyl fermions with opposite chirality,to be non-chiral.Inspired by the flavor symmetry in particle physics,we theoretically propose a massless Dirac-like equation yet linking two Weyl fields with the identical chirality by assuming SUe2T isospin symmetry,independent of the space-time rotation exchanging the two fields.Dramatically,such symmetry is hidden in certain solid-state spin-1/2 systems with negligible spinorbit coupling,where the spin degree of freedom is decoupled with the lattice.Therefore,the existence of the corresponding quasiparticle,dubbed as flavor Weyl fermion,cannot be explained by the conventional(magnetic)space group framework.The 4-fold degenerate flavor Weyl fermion manifests linear dispersion and a Chern number of±2,leading to a robust network of topologically protected Fermi arcs throughout the Brillouin zone.For material realization,we show that the transition-metal chalcogenide CoNb3S6 with experimentally confirmed collinear antiferromagnetic order is ideal for flavor Weyl semimetal under the approximation of vanishing spin-orbit coupling.Our work reveals a counterpart of the flavor symmetry in magnetic electronic systems,leading to further possibilities of emergent phenomena in quantum materials.
