Preparation of ultrafine highly dispersed VO2(M) nanoparticles that are essential materials to fabricate thermochromic flexible films remains a challenge, preventing effective use their promising properties. Here, we report an original hydrothermal approach by controlling oxidizing atmosphere reaction with hydrogen peroxide prepare free from annealing. Hydrogen is separated precursor solution in reactor, which creates moderate oxygenation environment, enabling the formation stoichiometric...

Vanadyl phosphate (VOPO4) is an attractive candidate as a Li-ion battery cathode with potential to reach higher energy density than that of olivine LiFePO4. However, the limited knowledge complex polymorphism VOPO4 and LiVOPO4 prevents any systematic optimization. Here we present comprehensive first-principles study on phase stability its impact electrochemical properties. βVOPO4 αLiVOPO4 are predicted be most stable phases LiVOPO4, respectively. The crucial factor determines connection...

A correct understanding of the effects dopants and electric field on metal–insulator transition VO2 remains a challenge. Herein, theoretical experimental studies are performed to elucidate role W transition. found introduce additional localized electrons in d bands, which induce splitting d// orbitals V–V dimerization local V ions W-doped R-VO2. The experiments electric-field-driven MIT nanofilms indicate that conductivity R-VO2 increases with increasing applied voltage; however, for pure...

VO2-based thermochromic films are promising candidates for new-generation energy-saving smart windows. However, the overly high transition temperature of metal–insulator (TMIT), low visible transmittance (Tlum), and unsatisfying solar modulation (ΔTsol) limit their application. W doping is an effective way to lower TMIT but simultaneously deteriorates optical VO2. In this work, a Sn–W co-doping approach proposed effectively meanwhile acquire improved Tlum satisfy our results, adding Sn in...

Coherent radio emission mechanism of solar bursts is one the most complicated and controversial topics in physics. To clarify mechanism(s) different types bursts, (radio) wave excitation by energetic electrons homogeneous plasmas has been widely studied via particle-in-cell (PIC) code numerical simulations. The corona is, however, inhomogeneous over almost all spatial scales. Inhomogeneities plasma could influence properties bursts. In this paper, we, hence, investigate effects inhomogeneity...

Ultrafine M-phase VO2 nanocrystals with good crystallinity are desirable for highly efficient thermochromic flexible films. Herein, we report an oxygen-controlled hydrothermal method to achieve the one-step preparation of stoichiometric and size-controllable VO2(M) nanoparticles scaled-up production. The specific ratio oxygen intake V ions was first determined guarantee acquisition VO2(M). Then, conditions were optimized perform growth nanoparticles. average particle sizes 25, 32, 41, 52 nm...

The smart radiator device (SRD) with low solar absorption (αs) and large infrared emittance modulation (Δɛ) is desirable to a spacecraft thermal control system. In this work, the SRD was fabricated through depositing Ag/Al2O3/VO2 triple-layer film on Si substrate by magnetron sputtering. properties of devices were optimized tuning thickness VO2 layer, fantastic acquired, which showed αs, high Δɛ, intense high-temperature (ɛHT). For layer 50 nm thickness, αs as 29.7% Δɛ reached 0.53 ɛHT up...

Abstract Practical applications of computed tomography (CT) in optical engines require an advanced algorithm that can correct the light refraction via windows and reconstruct 3D signal field partially blocked by structural obstacles. In this work, CT is designed for to simultaneously eliminate imaging distortion diminish reconstruction errors using partial blocking. By combining pinhole model Snell’s law, ray tracings from discretized voxels measurement domain 2D pixels planes are accurately...

The formation mechanism of the metastable M2-phase VO2, which is believed to be a true Mott insulator, has attracted great attention for understanding intriguing physics metal–insulator transition VO2 and promising application in ultrafast electronic switching devices. Herein, we conducted hole-doping calculation regardless type element revealed theoretically that hole carriers disentangle complex Mott–Peierls relevance states M1-phase VO2. induces zigzag dimerized V–V chains separate into...

This work reports the development and validation of a new tomography approach, termed cross-interfaces computed (CICT), to address confined-space problems. Many practical problems require imaging through optical walls, which may encounter light refractions that seriously influence process deteriorate three-dimensional (3D) reconstruction. Past efforts have primarily focused on developing open-space algorithms, but these algorithms are not extendable unless from 3D target its line-of-sight...

Tomographic approaches in confined space require advanced imaging algorithms that can properly consider the refractive distortion as rays pass through optical wall. Our previous work established an algorithm (cross-interfaces computed tomography, CICT) and practically solved tomographic problems space. However, critical restriction was found CICT, which is images simulated at small azimuth angles are contaminated with noticeable signal loss become unusable. Based on this recognition, has...

This work reports the modification and optimization of a computed tomography (CT) algorithm to become capable resolving an optical field with internal blockage (IOB) present. The IOB-practically, opaque mechanical parts installed inside measurement domain-prevents portion emitted light from transmitting sensors. Such disrupts line-of-sight intensity integration on recorded projections eventually leads incorrect reconstructions. In modified developed in this work, positions obstacle are...

The oxygen transport behavior in c-axis-oriented YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films has been investigated by means of electrical conductivity relaxation measurements. surface exchange coefficients have determined from the out- and in-diffusion when partial pressure was switched between pO/sub 2/ = 0.01 atm 0.02 at temperatures 773 K to 873 K. results are described a model which molecules dissociated two different sites, diffuse rapidly along grain boundaries act as "chimneys."...

Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO2 has served as a prototype due to its favorable temperature. While physical underpinnings of have been heavily investigated experimentally computationally, quantitative modeling electronic transport in two phases yet be undertaken. In this work, we establish...

Infrared emitter is highly desirable for applications in infrared imaging and stealth technology. It also a core device scene generation. Light-driven photothermal film has attracted considerable interest due to its outstanding properties easy fabrication. However, the existing films suffer from low conversion efficiency (PCE) as well small sizes. The improvement of PCE usually achieved at expense dynamic frame rate. Here, this work designs fabricates based on 3D self-suspended microbridge...