The sun (∼6,000 K) and outer space (∼3 K) are two significant renewable thermodynamic resources for human beings on Earth. The solar thermal conversion by photothermal (PT) and harvesting the coldness of outer space by radiative cooling (RC) have already attracted tremendous interest. However, most of the PT and RC approaches are static and monofunctional, which can only provide heating or cooling respectively under sunlight or darkness. Herein, a spectrally self-adaptive absorber/emitter (SSA/E) with strong solar absorption and switchable emissivity within the atmospheric window (i.e., 8 to 13 μm) was developed for the dynamic combination of PT and RC, corresponding to continuously efficient energy harvesting from the sun and rejecting energy to the universe. The as-fabricated SSA/E not only can be heated to ∼170 °C above ambient temperature under sunshine but also be cooled to 20 °C below ambient temperature, and thermal modeling captures the high energy harvesting efficiency of the SSA/E, enabling new technological capabilities.
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http://dx.doi.org/10.1073/pnas.2120557119 | DOI Listing |
Sensors (Basel)
January 2025
The Blavatnik School of Computer Science and AI, Tel Aviv University, Tel Aviv 69978, Israel.
This article surveys the literature on miniature radio transmitters designed to track free-ranging wild animals using emitter-localization techniques. The articles covers the topics of power sources used in such transmitters, including miniature batteries and energy harvesting, techniques for generating the transmitted radio-frequency carrier, techniques for creating short radio pulses and more general on-off schedules, modulation in modern wildlife-tracking transmitters, construction, manufacturing, and tuning techniques, and recent trends in this area. The article also describes the recreation of the first successful wildlife-tracking transmitter, a nontrivial invention that had a profound impact on wildlife ecology, and explores its behavior.
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January 2025
Department of Information Engineering, Electronics and Telecommunications (DIET), "La Sapienza" University of Rome, 00184 Rome, Italy.
This research proposes an all-metal metamaterial-based absorber with a novel geometry capable of refractive index sensing in the terahertz (THz) range. The structure consists of four concentric diamond-shaped gold resonators on the top of a gold metal plate; the resonators increase in height by 2 µm moving from the outer to the inner resonators, making the design distinctive. This novel configuration has played a very significant role in achieving multiple ultra-narrow resonant absorption peaks that produce very high sensitivity when employed as a refractive index sensor.
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January 2025
Faculty of Information and Communication Technology, University Tunku Abdul Rahman (UTAR), Kampar 31900, Perak, Malaysia.
This research presents an innovative polarization-insensitive metasurface (MS) harvester designed for energy harvesting applications at 5 GHz, capable of operating efficiently over wide reception angles. The proposed MS features a novel wheel-shaped resonator array whose symmetrical structure ensures insensitivity to the polarization of incident electromagnetic (EM) waves, enabling efficient energy absorption and minimizing reflections. Unlike conventional designs, the metasurface achieves near-unity harvesting efficiency, exceeds 94% under normal incidence, and maintains superior performance across various incident angles for TE and TM polarizations.
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January 2025
Institute of Nanotechnologies, Electronics and Equipment Engineering, Southern Federal University, 347922 Taganrog, Russia.
One of the challenging problems in the research and development of vibration sensors relates to the formation of Ohmic contacts for the removal of an electrical signal. In some cases, it is proposed to use arrays of carbon nanotubes (CNTs), which can serve as highly elastic electrode materials for vibration sensors. The purpose of this work is to study the effect of a current-collecting layer of CNTs grown over silicon on the properties of a lead zirconate titanate (PZT) film, which is frequently employed in mechanical vibration sensors or energy harvesters.
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January 2025
National Key Laboratory of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu 611731, China.
A communication network integrating multiple modes can effectively support the sustainable development of next-generation wireless communications. Integrated sensing, communication, and power transfer (ISCPT) represents an emerging technological paradigm that not only facilitates information transmission but also enables environmental sensing and wireless power transfer. To achieve optimal beamforming in transmission, it is crucial to satisfy multiple constraints, including quality of service (QoS), radar sensing accuracy, and power transfer efficiency, while ensuring fundamental system performance.
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