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Passive daytime radiative cooling that could provide sub-ambient cooling emerges as a promising technology to reduce household energy consumption. Nonetheless, prevailing studies are predominantly focused on surface cooling, often overlooking its adaptability to enclosed spaces with active cooling technologies. Here we present a multilayer radiative cooling film (J-MRC) with Janus optical properties in the mid-infrared region, consisting of the nanoporous polyethylene films, the polyethylene oxide film, and silver nanowires. The top side of the J-MRC functions as a conventional radiative cooling material to supply sub-ambient surface cooling, while the bottom side with low mid-infrared emissivity transfers limited heat via thermal radiation to the low-temperature enclosures. Our experiments validate that the J-MRC possesses an enhanced space cooling performance in comparison to the conventional radiative cooling film. This work provides a valuable design concept for radiative cooling materials, thereby expanding their practical scenarios and contributing to reduce the carbon emission.

High-precision detection of electric charge is critical for physical, chemical, and biological measurements. Nanophotonic optomechanical system confines the optical field at the nanoscale and enables a strong interaction between optical cavity and mechanical resonator. Its high optical quality factor cavity and strong optomechanical coupling are promising for precision sensing applications. Here an integrated optomechanical electrometer is proposed for the electric charge sensing using a zipper cavity with a suspended photonic crystal nanobeam (PCN) acting as a movable mechanical resonator. As the electrostatic force arising from the electric voltage to be measured interacts with the mechanical motion of the movable PCN and modulates its resonance through electrostatic stiffening effect, optomechanical coupling transduces the mechanical motion to the optical field with enhanced sensitivity. The resonance shift of the mechanical resonator can be monitored to detect the electric voltage with a sensitivity of 0.007 Hz/mV2$\mathrm{Hz}/\mathrm{m}{\mathrm{V}}^{2}$. Moreover, the sensing performance can be further enhanced with the operation of the optomechanical electrometer in the self-sustained oscillation above threshold power. Owing to the narrow-linewidth of detector radio frequency (RF) spectrum with a large peak-to-noise floor ratio (up to 73.5 dB), the enhanced electrical sensitivity of 0.014 Hz/mV2$\mathrm{Hz}/\mathrm{m}{\mathrm{V}}^{2}$ is achieved with a high resolution of 1.37 mV2Hz−1/2$1.37\,\mathrm{m}{\mathrm{V}}^{2}\mathrm{H}{\mathrm{z}}^{-1/2}$. A theoretical minimal detectable electrostatic charge is calculated as 1.33×10−2 eHz−1/2$1.33{\times}{10}^{-2}\,\mathrm{eH}{\mathrm{z}}^{-1/2}$ by converting the measured electric voltage versus RF shift to an approximatively linear relationship. This on-chip optomechanical electrometry scheme provides a powerful solution to the ultrasensitive determination of charged nanoparticles in biological and chemical applications.

Due to the poor aqueous solubility of docosahexaenoic acid (DHA), encapsulating it in egg yolk results in a reduction in the hydration properties of egg yolk powder (EYP), subsequently affecting its functional properties. In this study, the effects of vacuum low-temperature spray drying (VLTSD), high-temperature spray drying (HTSD), and freeze-drying (FD) on the hydration properties of DHA-enriched EYP were investigated. Firstly, we optimized the inlet temperature and feed rate for VLTSD (60 °C, 300 mL/h) and HTSD (170 °C, 800 mL/h), while FD was conducted under − 70 °C conditions. The most striking finding of this study was the DHA-enriched EYP prepared by VLTSD exhibited desirable solubility (54.86 g/100 g), water dispersibility (48.63%), and coefficient of stability (24.88%) during rehydration, which was well predicted by low-field NMR. Compared to HTSD and FD, the solubility increased by 16.18% and 45.17%, respectively. Furthermore, at the microscopic level, SEM images and FTIR spectra revealed that VLTSD enhanced the hydration properties by protecting the structural integrity and increasing the hydrogen bonding of the DHA-enriched EYP. The encapsulation efficiency of DHA-enriched EYP prepared by VLTSD, HTSD, and FD were 97.15%, 96.51%, and 81.31%, respectively. According to the quality analysis, VLTSD had the best protection for DHA-enriched EYP in terms of chromaticity, bulk density, storage stability, and sensory evaluation. Therefore, this study confirmed the applicability of VLTSD technology for microencapsulation of bioactive substances such as DHA to enhance the hydration properties of powders. [ABSTRACT FROM AUTHOR]

The enhancement of plasma generation in atmospheric pressure dielectric barrier discharge (DBD) is gaining increasing interest for various plasma applications. In this paper, the effect of surface charges moving with the rotating dielectric plate on improving the generation of streamer channels is investigated by a statistical analysis of electrical measurements, optical diagnostics, and numerical simulation in a needle-plate DBD device with a rotating dielectric plate. Results suggest that rotating the dielectric plate can improve the spatiotemporal distribution of streamer channels by inducing a bending of the streamer channels and an increase in the number of discharges. Statistical results show that the number of current pulse and discharge energy are increased by 20% and 47%, respectively, at the rotating speed of 160 rps (revolution per second). Based on the interaction between the applied electric field and the electric field induced by surface charges, a formula is proposed to govern the effect of rotating the dielectric plate on the discharge energy and streamer bending. To further understand the mechanism of the influence of rotating the dielectric plate on plasma properties, a 2D fluid model is implemented, and the reduced electric field and streamer propagation are analyzed. Results show that the effective transfer and reuse of surface charges play an important role in the enhancement of plasma generation. [ABSTRACT FROM AUTHOR]

For aqueous zinc-ion batteries, comprehensively optimizing the Zn/electrolyte interface microenvironment is an effective strategy to avoid harmful side reactions and Zn dendrites and thus helps to achieve a high-performance Zn anode. Herein, a functional vinylene-linked covalent organic framework with zincophilic fluorinated sites (TM-4F-COF) is well designed and applied as an interface layer, which modifies the chemical microenvironment at the Zn/electrolyte interface to simultaneously manipulate the Zn plating/stripping behaviors and interfacial side reactions. The TM-4F-COF layer can accelerate Zn2+ de-solvation and interfacial Zn2+ transfer due to the abundant zincophilic fluorinated sites, consequently facilitating the formation of a uniform Zn2+ re-distribution layer. Furthermore, an even electric field is realized at the TM-4F-COF/Zn interface due to the conjugated structure of TM-4F-COF, and the preferentially formed Zn(002) results in a horizontally dense Zn deposition to provide dendrite-free features and high reversibility. A TM-4F-COF@Zn symmetrical cell exhibits an ultra-long cyclability of 2935 h at 3 mA cm−2. Our work provides a fundamental strategy to fabricate a stable Zn anode for high-performance aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

Enhancing discharge energy in dielectric barrier discharge (DBD) is vital for various applications. This study establishes a theoretical formula for predicting enhanced discharge in multi‐needle‐plate (MP) DBD, accounting for factors like needle count, rotation speed, and voltage frequency. Experiments validate the formula's accuracy, showing that precisely matched parameters result in enhanced discharge power, heightened streamer luminosity, and curved streamer channels. Lissajous figures in MP DBD exhibit elliptical shapes due to residual discharges during voltage fall. Statistical analysis of current pulses and discharge images confirms that dielectric plate rotation increases discharges and extends their duration during voltage fall. Numerical simulations highlight surface charge movement's role in enhancing the electric field and affecting streamer propagation direction in the air gap. [ABSTRACT FROM AUTHOR]