We propose a scheme for realizing nonreciprocal microwave photon routing with two cascaded magnon-cavity coupled systems, which work around the exceptional points of a parity-time (PT)-symmetric Hamiltonian. An almost perfect nonreciprocal transmission can be achieved with a broad bandwidth, where the transmission for a forward-propagating photon can be flexibly controlled with the backpropagating photon being isolated. The transmission or isolated direction can be reversed via simply controlling the magnetic field direction applied to the magnons.
View Article and Find Full Text PDFIn this paper, we propose an optomechanical scheme for generating mechanical squeezing over the 3 dB limit, with the mechanical mirror being driven by a strong and linear harmonic force. In contrast to parametric mechanical driving, the linearly driven force shakes the mechanical mirror periodically oscillating at twice the mechanical eigenfrequency with large amplitude, where the mechanical mirror can be dissipatively stabilized by the engineered cavity reservoir to a dynamical squeezed steady state with a maximum degree of squeezing over 8 dB. The mechanical squeezing of more than 3 dB can be achieved even for a mechanical thermal temperature larger than 100 mK.
View Article and Find Full Text PDFWaste resource utilization of petroleum coke is crucial for achieving global carbon emission reduction. Herein, a series of N-doped microporous carbons were fabricated from petroleum coke using a one-pot synthesis method. The as-prepared samples had a large specific surface area (up to 2512 m/g), a moderate-high N content (up to 4.
View Article and Find Full Text PDFPore distribution characteristic is one of the most crucial factors for porous adsorption materials, and the variety of volatile organic compounds (VOCs) approaches about how to simply and accurately tailor practical porous carbons for VOCs adsorption has gradually attracted attention. Here, precursors with different lignocellulose mass ratios have been used to produce porous carbon for model experiments to investigate the influence of the precursor lignocellulose contents on the pore structure and distribution characteristics of porous carbon, and the applicability of these mechanisms to real biomass materials has been further verified through bacteria-targeted bagasse decomposition: the microvolumes of ultra-micropores have decreased with decrease in cellulose contents, while mesopores have followed the reverse trend. The dynamic toluene adsorption/desorption performances of the obtained samples have been tested.
View Article and Find Full Text PDFBiomass-derived porous carbonaceous materials are efficient adsorbents for VOCs, but their traditional preparation method, pyrolysis combined with activation, suffers from high energy consumption, equipment corrosion, and low pore-making efficiency, which hinders their large-scale practical application. A novel method of alkali metal-catalyzed hydrothermal carbonization coupling with chemical activation for the preparation of microporous carbon is presented. Porous carbon with well-developed microporosity deriving from corn husk were prepared through the hydrothermal carbonization using potassium persulfate (KSO) as a catalyst and programmed heating activation process.
View Article and Find Full Text PDFTo achieve carbon neutrality, it is necessary to control carbon-based gas emissions to the atmosphere. Among the various carbon-based gas removal technologies reported to date, adsorption is considered one of the most promising because of its economic efficiency, reusability, and low energy consumption. Activated carbon is widely used to treat different types of carbon-based gases owing to its large specific surface area, abundant functional groups, and strong adsorption capacity.
View Article and Find Full Text PDFVolatile organic compounds (VOCs), which are usually organic compounds with boiling point in the range of 50 to 260°C, pose a serious threat to human health and ecological environment. In order to find an adsorbent with excellent adsorption effect on VOCs, activated carbon was prepared from corn bran partially degraded by Trichoderma viride, and the adsorption performance of the optimized porous carbon materials on toluene was studied. Physical and chemical properties (such as specific surface area, pore size distribution, and surface functional groups) of the activated carbon were characterized by scanning electron microscope (SEM), N adsorption/desorption experiences, Fourier-transform infrared (FTIR), and Raman and X-ray diffraction (XRD).
View Article and Find Full Text PDFThe porous carbon materials formed from biomass precursors are promising candidates for adsorbing organic vapor pollutants. However, these materials have insufficient pores, which hinder their accessibility to adsorbates. This study develops an ultrahigh-surface-area porous carbon adsorbent with interlacing micro-mesoporous structures through Trichoderma viride decomposition.
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