High-throughput identification of one-dimensional atomic wires and first principles calculations of their electronic states

Low dimensional materials are suitable candidates applying in next-generation high-performance electronic,optoelectronic,and energy storage devices because of their uniquely physical and chemical properties.In particular,one-dimensional(1D)atomic wires(AWs)exfoliating from 1D van der Waals(vdW)bulks are more promising in next generation nanometer(nm)even sub-nm device applications owing to their width of few-atoms scale and free dandling bonds states.Although several 1D AWs have been experimentally prepared,few 1D AW candidates could be practically applied in devices owing to lack of enough suitable 1D AWs.Herein,367 kinds of 1D AWs have been screened and the corresponding computational database including structures,electronic structures,magnetic states,and stabilities of these 1D AWs has been organized and established.Among these systems,unary and binary 1D AWs with relatively small exfoliation energy are thermodynamically stable and theoretically feasible to be exfoliated.More significantly,rich quantum states emerge,such as 1D semiconductors,1D metals,1D semimetals,and 1D magnetism.This database will offer an ideal platform to further explore exotic quantum states and exploit practical device applications using 1D materials.The database are openly available at http://www.dx.doi.org/10.11922/sciencedb.j00113.00004.

Nature of magnetic and electronic structure of double perovskite A_2FeMoO_6

The nature of magnetic and electronic structure in double perovskite structure A2FeMoO6(A = Sr,a,Ca) was calculated using the local spin density approximation(LSDA) and the LSDA+U Coulomb interaction method of density functional theory. The result shows that Sr2FeMoO6 is magnetic metallic material,whereas Ba2FeMoO6 and Ca2FeMoO6 are half-metallic materials. Fe has great effect on the magnetic property of double perovskite structure A2FeMoO6 materials. Because of the orbit hybridization and polarization between the metal element and O element,the Mo element has magnetic properties. The static magnetic moment of double perovskite structure A2FeMoO6 materials,the value of the magnetic moment of these A2FeMoO6 for(A=Ca,Sr,Ba) are 3.626 43μB,2.678 64μB,3.706 17μB,respectively. The magnetic moment of Fe element in the crystal cell are,3.626 43μB,2.678 64 μB,3.706 17μB. And the energy of crystal cells are -28 540.561 907Ry,-24 268.037 272Ry,-44 106.187 179Ry. These values are in agreement with the experiment values.

Conformal Human–Machine Integration Using Highly Bending‑Insensitive,Unpixelated,and Waterproof Epidermal Electronics Toward Metaverse

Efficient and flexible interactions require precisely converting human intentions into computer-recognizable signals,which is critical to the breakthrough development of metaverse.Interactive electronics face common dilemmas,which realize highprecision and stable touch detection but are rigid,bulky,and thick or achieve high flexibility to wear but lose precision.Here,we construct highly bending-insensitive,unpixelated,and waterproof epidermal interfaces(BUW epidermal interfaces)and demonstrate their interactive applications of conformal human–machine integration.The BUW epidermal interface based on the addressable electrical contact structure exhibits high-precision and stable touch detection,high flexibility,rapid response time,excellent stability,and versatile“cut-and-paste”character.Regardless of whether being flat or bent,the BUW epidermal interface can be conformally attached to the human skin for real-time,comfortable,and unrestrained interactions.This research provides promising insight into the functional composite and structural design strategies for developing epidermal electronics,which offers a new technology route and may further broaden human–machine interactions toward metaverse.

Multifunctional and Reconfigurable Electronic Fabrics Assisted by Artificial Intelligence for Human Augmentation

Noninvasive human augmentation,namely a desirable approach for enhancing the quality of life,can be achieved through wearable electronic devices that interact with the external environment.Wearable electronic devices endure limitations,such as unreliable signal interaction when bent or deformed,excessive wiring requirements,and lack of programmability and multifunctionality.Herein,we report an intelligent and programmable(IP)fabric sensor with bending insensitivity that overcomes these challenges associated with a rapid response time(<400μs)and exceptional durability(>20,000 loading-unloading cycles).A single-layer parallel electrical bilateral structure is utilized to design the IP fabric sensor with reconfigurability and only two electrodes,which caters to the requirement of stable interactions and simple wiring.The multifunctionality of the IP fabric sensor is demonstrated by designing a closed-loop interactive entertainment system,a smart home system,and a user identification and verification system.This integrated system reveals the potential of combining Internet of Things technology and artificial intelligence(AI).Hopefully,the integration of the noninvasive IP fabric sensor with AI will facilitate the advancement of interactive systems for human augmentation.

Photoinduced Reconstruction of Electronic Structure in Half-Metal CrO2

We investigate the photoinduced effects on the electronic structure for half-metallic ferromagnet CrO2 （Tc 390 K）, in which the conducting electrons are totally polarized, by using the LSDA＋U method. A significant change is found for the band structure and the density of states （DOS） for CrO2 under photo-excitation, especially for the Cr 3dt2g band： disappearance of the spin-split band, suggesting collapse of the half-metallic state. We ascribe the change of electronic structure under photo-excitation to the wider one-electron band W via the strong hybridization of the down-spin Cr 3d and O 2p states. Furthermore we discuss the magnetic properties under photo-excitation.

Electronic and structural properties of N-vacancy in AlN nanowires:A first-principles study

The stability and electronic structures of AIN nanowires with and without N-vacancy are investigated using firstprinciples calculations. We find that there is an inverse correlation between formation energy and diameter in ideal AlN nanowires. After calculating the formation energies of N-vacancy at different sites in AlN nanowires with different diameters, we find that the N-vacancy prefers to stay at the surface of the nanowires and it is easier to fabricate them under Al-rich conditions. Through studying the electronic properties of AlN nanowires with N-vacancies, we further find that there are two isolated bands in the deep part of the band gap, one of them is fully occupied and the other is half occupied. The charge density indicates that the half-fully occupied band arises from the Al at the surface, and this atom becomes an active centre.

Nonclassical properties in the resonant interaction of a three level ∧-type atom with two-mode field in coherent state

In this paper, we study the nonclassical properties of the electromagnetic field resulting from the interaction of a three-level ∧-type atom with a two-mode field initially in the coherent state, such as squeezing properties and sub-Poisson statistics. We show that the squeezing can be enhanced by selective atomic measurement.

MICROWAVE PERMEABILITY SPECTRA OF SPUTTERED Fe-Co-B SOFT MAGNETIC THIN FILMS

Permeability characteristics of sputtered soft magnetic Fe40Co40B20 thin films are investigated in the range of O. 5 to 5 GHz by a shortened microstrip transmission line perturbation method. Excellent microwave permeability is achieved at 0.4 Pa argon pressure： fr is 3.32 GHz, the real and imaginary part of permeability at 0.5 GHz are 104 and 61, respectively. In addition, the thickness effect on permeability is also studied. The minimum damping can be achieved at the thinnest film. Different sources contributed to in-plane anisotropy are discussed briefly. The deviation between the peak frequency of the imaginary part and the zero-crossing frequency of the real part of permeability is also presented.

Tight Focusing of Radially and Azimuthally Polarized Vortex Beams through a Dielectric Interface

Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by numerical calculations. We show the influence of numerical-aperture （NA） on the full-width at half maximum （FWHM） of the focal spot or the focal hole. It has been found that compared with the azimuthally polarized Besse^Gaussian （BG） beams, the longitudinal component in the z direction of the radially polarized BG beams has no influence on the FWHM of the focal spot and hole, but enhances the total light intensity.

Teleportation of two-atom entangled state in resonant cavity quantum electrodynamics

An alternative scheme is presented for teleportation of a two-atom entangled state in cavity quantum electrodynamics （QED）. It is based on the resonant atom-cavity field interaction. In the scheme, only one cavity is involved, and the number of the atoms needed to be detected is decreased compared with the previous scheme. Since the resonant atom-cavity field interaction greatly reduces the interaction time, the decoherence effect can be effectively suppressed during the teleportation process. The experimental feasibility of the scheme is discussed. The scheme can easily be generalized to the teleportation of N-atom Greeninger-Horne-Zeilinger （GHZ） entangled states. The number of atoms needed to be detected does not increase as the number of the atoms in the GHZ state increases.

Effects of initial frequency chirp on the linear propagation characteristics of the exponential optical pulse

In this paper, the linear propagation characteristics of the exponential optical pulse with initial linear and nonlinear frequency chirp are numerically studied in a single mode fibre for β2 〈 0. It can be found that the temporal full width at half maximum and time-bandwidth product of exponential pulse monotonically increase with the increase of propagation distance and decrease with the increase of linear chirp C for C 〈 0.5, go through an initial decreasing stage near ζ= 1, then increase with the increase of propagation distance and linear chirp C for C 〉 0.5. The broadening of pulses with negative chirp is faster than that with positive chirp. The exponential pulse with linear chirp gradually evolves into a near-Gaussian pulse. The effect of nonlinear chirp on waveform of the pulse is much greater than that of linear chirp. The temporal waveform breaking of exponential pulse with nonlinear chirp is first observed in linear propagation. Furthermore, the expressions of the spectral width and time-bandwidth product of the exponential optical pulse with the frequency chirp are given by use of the numerical analysis method.

Propagation of Airy beams from right-handed material to left-handed material

Based on the ABCD matrix formalism,the propagation property of an Airy beam from right-handed material（RHM） to left-handed material（LHM） is investigated.The result shows that when the Airy beam propagates in the LHM,the intensity self-bending due to its propagation in the RHM can be compensated.In particular,if the propagation distance in the RHM is equal to that in the LHM and the refractive index of the LHM is n L =-1,the transverse intensity distribution of the Airy beam can return to its original state.

Focusing of Partially Coherent Vortex Beams by an Aperture Lens

The focusing properties of partially coherent vortex wave fields are studied. Expressions are derived for the intensity distribution and the degree of coherence near the geometrical focus. It is found that the size of coherence vortex dark core in the focal region depends on the topological charges and normalized coherence lengths. It is found that the desired vortex dark core near the geometrical focus can be generated by choosing appropriate values of parameters. The degree of coherence possesses a pair of phase singularities regions in the geometrical focus neighbourhood.

Effect of rGO Coating on Interconnected Co_3O_4 Nanosheets and Improved Supercapacitive Behavior of Co_3O_4/rGO/NF Architecture

In this study, the effect of reduced graphene oxide(rGO) on interconnected Co_3O_4 nanosheets and the improved supercapacitive behaviors is reported. By optimizing the experimental parameters, we achieved a specific capacitance of ~1016.4 F g^(-1) for the Co_3O_4/rGO/NF(nickel foam) system at a current density of 1 A g^(-1). However, the Co_3O_4/NF structure without rGO only delivers a specific capacitance of ~520.0 F g^(-1)at the same current density. The stability test demonstrates that Co_3O_4/rGO/NF retains ~95.5% of the initial capacitance value even after 3000 charge–discharge cycles at a high current density of 7 A g^(-1). Further investigation reveals that capacitance improvement for the Co_3O_4/rGO/NF structure is mainly because of a higher specific surface area(~87.8 m^2g^(-1))and a more optimal mesoporous size(4–15 nm) compared to the corresponding values of 67.1 m^2g^(-1) and 6–25 nm,respectively, for the Co_3O_4/NF structure. rGO and the thinner Co_3O_4 nanosheets benefit from the strain relaxation during the charge and discharge processes, improving the cycling stability of Co_3O_4/rGO/NF.

Temporal development of open-circuit bright photovoltaic solitons

This paper investigates the temporal behaviour of open-circuit bright photovoltaic spatial solitons by using numerical techniques. It shows that when the intensity ratio of the soliton, the ratio between the soliton peak intensity and the dark irradiance, is small, the quasi-steady-state soliton width decreases monotonically with the increase of τ-, where τ- is the parameter correlated with the time, that when the intensity ratio of the soliton is big, the quasi-steady-state soliton width decreases with the increase of τ- and then increases with τ, and that the formation time of the steady-state solitons is not correlated with the intensity ratio of the soliton. It finds that the local nonlinear effect increases with the photovoltaic field, which behaves as that the width of soliton beams is small and the self-focusing quasi-period is short. On the other hand, we also discuss that both the time and the temperature have an effect on the beam bending.

An overview on the principle of inkjet printing technique and its application in micro-display for augmented/virtual realities

Augmented reality(AR)and virtual reality(VR)are two novel display technologies that are under updates.The essential feature of AR/VR is the full-color display that requires high pixel densities.To generate three-color pixels,the fluorescent color conversion layer inevitably includes green and red pixels.To fabricate such sort of display kits,inkjet printing is a promising way to position the color conversion layers.In this review article,the progress of AR/VR technologies is first reviewed,and in succession,the state of the art of inkjet printing,as well as two key issues-the optimization of ink and the reduction of coffee-ring effects,are introduced.Finally,some potential problems associated with the color converting layer are highlighted.

Enhancement of corona discharge induced wind generation with carbon nanotube and titanium dioxide decoration

Dip-coated double-wall carbon nanotubes(DWCNTs) and titanium dioxide(TiO2) sol have been prepared and smeared onto the tip of a conductive iron needle which serves as the corona discharge anode in a needle-cylinder corona system.Compared with the discharge electrode of a CNT-coated needle tip, great advancements have been achieved with the TiO_2/CNT-coated electrode, including higher discharge current, ionic wind velocity, and energy conversion efficiency,together with lower corona onset voltage and power consumption.Several parameters related to the discharge have been phenomenologically and mathematically studied for comparison.Thanks to the morphology reorientation of the CNT layer and the anti-oxidation of TiO_2, better performance of corona discharge induced wind generation of the TiO2/CNT-coated electrode system has been achieved.This novel decoration may provide better thoughts about the corona discharge application and wind generation.

Preparation and study on performance of submicron nickel powder for multilayer chip positive temperature coefficient resistance

Base metal nickel is often used as the inner electrode in multilayer chip positive temperature coefficient resistance （PTCR）. The fine grain of ceramic powders and base metal nickel are necessary. This paper uses reducing hydrazine to gain submicron nickel powder whose diameter was 200-300 nm through adjusting the consumption of nucleating agent PVP properly. The submicron nickel powder could disperse well and was fit for co--fired of multilayer chip PTCR. It analyes the submicron nickel powder through x-ray Diffraction （XRD） and calculates the diameter of nickel by PDF cards. Using XRD analyses it obtains several conclusions： If the molar ratio of hydrazine hydrate and nickel sulfate is kept to be a constant, when enlarging the molar ratio of NaOH/Ni^2＋, the diameter of nickel powder would become smaller. When the temperature in the experiment raises to 70-80 ℃, nickel powder becomes smaller too. And if the molar ratio of NaOH/Ni2＋ is 4, when molar ratio of （C2H5O）2/Ni^2＋ increases, the diameter of nickel would reduce. Results from viewing the powders by optical microscope should be the fact that the electrode made by submicron nickel powder has a better formation and compactness. Furthermore, the sheet resistance testing shows that the electrode made by submicron nickel is smaller than that made by micron nickel.

Measurement Induced Enhancement of Squeezing in Nondegenerate Two-Photon Jaynes-Cummings Model

Squeezing properties in the nondegenerate two-photon Jaynes-Cummings model are investigated. The effects of direct selective atomic measurement and the application of the classical field followed by atomic measurement are analyzed. Different values of the parameters of the classical field are taken into account. It is found that the field squeezing can be enhanced by measurement.

Teleportation of atomic states with a weak coherent cavity field

A scheme is proposed for the teleportation of an unknown atomic state. The scheme is based on the resonant interaction of atoms with a coherent cavity field. The mean photon-number of the cavity field is much smaller than one and thus the cavity decay can be effectively suppressed. Another advantage of the scheme is that only one cavity is required.