We employed the CST Microwave Studio software 2020 and the FDID algorithm for simulation. We have designed a terahertz broadband absorber based on Dirac semimetals and graphene, achieving continuous broadband absorption with a rate exceeding 80% over the range from 7.6776 to 9.172 THz. This broadband absorber features two independent tuning modes, utilizing graphene and Dirac semimetals, and exhibits strong electromagnetic adaptability. Furthermore, we conducted an in-depth analysis of the physical mechanisms underlying the high absorption in these absorbers using impedance matching theory and localized surface plasmon resonance (LSPR) theory. Variations in the dielectric constants of different dielectric layers and the relaxation time of graphene can also modulate the absorption rate. In summary, our proposed terahertz broadband absorber, employing two distinct tunable materials, enhances the device’s flexibility and environmental adaptability, offering promising prospects for wideband absorption applications.

Due to the equipartition exciton property of graphene metamaterials, researchers have applied them to the design of absorbers and developed a series of absorbers covering different wavebands (including narrowband and broadband). In this paper, an absorber based on surface-isotropic excitations was designed with the help of graphene metamaterials and relevant simulations. The absorber exhibited six perfect absorption peaks in the mid-infrared band and had an extremely simple structure consisting of only three layers: a gold layer at the bottom, a dielectric layer made of silica in the middle, and patterned graphene at the top. This absorber possesses excellent tuning ability, and by applying an external bias to the graphene layer, the Fermi energy level of graphene can be adjusted, and thus the resonance frequency of the absorption peak can be tuned. Meanwhile, the effect of the graphene relaxation time on the absorber performance was investigated. In addition, the refractive index of the dielectric layer was found to be linearly related to the resonance frequency of the absorption peak. It is worth mentioning that the absorber structure possessed polarization insensitivity due to its central symmetry. Even when incident light with different polarizations was incident over a wide range of angles, the change in absorbance of the absorption peaks was negligible, demonstrating significant insensitivity to the angle of incidence. The sensor possesses excellent characteristics such as tunability, polarization insensitivity, incident angle insensitivity, and high sensitivity. This paper demonstrates the feasibility of a six-frequency sensor and opens up more ideas for the design of multi-frequency sensors.

Spin Hall magnetoresistance (SMR) measurements provide a way to probe the surface spin structure of insulating magnetic materials. Such measurements produce resistance signals of the form ΔR ∝ cos[2(α-α_0)], where α is the angle between the current and the external in-plane magnetic field. Previous experiments on a wide range of materials have found α_0 = 0° for ferromagnets and α_0 = 90° for antiferromagnets. Here we investigate SMR in bilayers of Pt with monodomain BiFeO_3 multiferroic epitaxial thin films. We observe signals of the form ΔR ∝ cos[2(α-α_0)] but surprisingly the angle α_0 can take values very different from 90° or 0°, with large variations from sample to sample. The aim of the paper is to report this striking departure from the expected magnetic field dependence of SMR and to encourage consideration of possible microscopic mechanisms.

This paper presents a photonic crystal fiber (PCF) sensor that can be used to measure the temperature and magnetic field simultaneously, and to monitor the changes in them in the environment. When we designed the fiber structure, two circular channels of the same size were added to the fiber to facilitate the subsequent addition of materials. A gold film is added to the upper channel (ch1), and the channel is filled with a magnetic fluid (MF). The sensor can reflect changes in the temperature and magnetic field strength. The two channels containing MF and PDMS in the proposed fiber are called ch1 and ch2. The structure, mode and properties (temperature and magnetic field) were analyzed and discussed using the finite element method. By using the control variable method, the influence of Ta2O5 or no Ta2O5, the Ta2O5 thickness, the diameter of the special air hole, the distance from the fiber core and the distance between them in the displacement of the loss spectrum and the phase-matching condition of the coupling mode were studied. The resulting maximum temperature sensitivity is 6.3 nm/°C (SPR peak 5), and the maximum magnetic field sensitivity is 40 nm/Oe (SPR peak 4). Because the sensor can respond to temperature and magnetic field changes in the environment, it can play an important role in special environmental monitoring, industrial production and other fields.

In recent years, solar energy has become popular because of its clean and renewable properties. Meanwhile, two-dimensional materials have become a new favorite in scientific research due to their unique physicochemical properties. Among them, monolayer molybdenum disulfide (MoS2), as an outstanding representative of transition metal sulfides, is a hot research topic after graphene. Therefore, we have conducted an in-depth theoretical study and design simulation using the finite-difference method in time domain (FDTD) for a solar absorber based on the two-dimensional material MoS2. In this paper, a broadband solar absorber and thermal emitter based on a single layer of molybdenum disulfide is designed. It is shown that the broadband absorption of the absorber is mainly due to the propagating plasma resonance on the metal surface of the patterned layer and the localized surface plasma resonance excited in the adjacent patterned air cavity. The research results show that the designed structure boasts an exceptional broadband performance, achieving an ultra-wide spectral range spanning 2040 nm, with an overall absorption efficiency exceeding 90%. Notably, it maintains an average absorption rate of 94.61% across its spectrum, and in a narrow bandwidth centered at 303 nm, it demonstrates a near-unity absorption rate, surpassing 99%, underscoring its remarkable absorptive capabilities. The weighted average absorption rate of the whole wavelength range (280 nm–2500 nm) at AM1.5 is above 95.03%, and even at the extreme temperature of up to 1500 K, its heat radiation efficiency is high. Furthermore, the solar absorber in question exhibits polarization insensitivity, ensuring its performance is not influenced by the orientation of incident light. These advantages can enable our absorber to be widely used in solar thermal photovoltaics and other fields and provide new ideas for broadband absorbers based on two-dimensional materials.

Understanding and further regulating the degradation of mandrel materials is a key aspect of target fabrication in inertial confinement fusion (ICF). Here, a quasi-one-dimensional confinement model is developed using a series of single-walled carbon nanotubes with varying diameters (Dm), and the degradation of poly-α-methylstyrene (PAMS) as a typical mandrel material is investigated under such confined conditions by using the combined method of quantum mechanics and molecular mechanics. In comparison to the isolated system, the calculations show that confinement can decrease or increase the energy barriers of PAMS degradation, which directly depends on Dm. Following which a clear exponential relationship between the degradation rate of PAMS and its own density is derived, indicating that the density of PAMS can be used to regulate mandrel degradation. This work highlights the important effects of confinement on degradation and provides a valuable reference for further development of polymer degradation technologies in ICF target fabrication and other fields.

Since the use of chemical fuels is permanently damaging the environment, the need for new energy sources is urgent for mankind. Given that solar energy is a clean and sustainable energy source, this study investigates and proposes a six-layer composite ultra-wideband high-efficiency solar absorber with an annular microstructure. It achieves this by using a combination of the properties of metamaterials and the quantum confinement effects of semiconductor materials. The substrate is W-Ti-Al2O3, and the microstructure is an annular InAs-square InAs film-Ti film combination. We used Lumerical Solutions' FDTD solution program to simulate the absorber and calculate the model's absorption, field distribution, and thermal radiation efficiency (when it is used as a thermal emitter), and further explored the physical mechanism of the model's ultra-broadband absorption. Our model has an average absorption of 95.80% in the 283-3615 nm band, 95.66% in the 280-4000 nm band, and a weighted average absorption efficiency of 95.78% under AM1.5 illumination. Meanwhile, the reflectance of the model in the 5586-20,000 nm band is all higher than 80%, with an average reflectance of 94.52%, which has a good thermal infrared suppression performance. It is 95.42% under thermal radiation at 1000 K. It has outstanding performance when employed as a thermal emitter as well. Additionally, simulation results show that the absorber has good polarization and incidence angle insensitivity. The model may be applied to photodetection, thermophotovoltaics, bio-detection, imaging, thermal ion emission, and solar water evaporation for water purification.

When surface plasmon resonance (SPR) occurs, the incident light is absorbed by the surface of the SPR structure, thus minimizing the intensity of the reflected light. Therefore, the SPR method is adopted in this paper to achieve perfect absorption of the absorbent. In this paper, we first propose a multi-frequency broadband absorber structure based on graphene SPR, which uses the continuous resonance of patterned graphene surface plasmon in the frequency spectrum to form a multi-frequency broadband absorption. In this simulation, a sandwich-stack structure was adopted, whereby the patterned graphene is situated on top of the SiO2 layer and the metal layer. The broad-band absorption bands of the absorber were obtained as 4.14–4.38 THz, 5.78–6.36 THz, and 7.87–8.66 THz through the analog simulation of finite-difference time-domain method (FDTD) solutions. Then, based on the multi-layer resonant unit structure, through the superposition and combination of absorbing units responding to different frequency bands, the perfect absorption of ultra-wideband is achieved. The data results illustrate that the total absorption bandwidth of the absorber is 2.26 THz, and the relative absorption bandwidth Bw is equal to 28.93%. The electric field in X-Y direction of the absorber in the perfect absorption band is analyzed, respectively, and the dynamic tunability of the absorber is studied. Finally, we studied whether the absorbing structure still has efficient absorption characteristics for the two polarization modes when the incident angle is changed from 0° to 70°. The structure model proposed has potential value for application in terahertz photoelectric detection, filtering, and electromagnetic shielding.

Here, we document a D-type double open-loop channel floor plasmon resonance (SPR) photonic crystal fiber (PCF) for temperature sensing. The grooves are designed on the polished surfaces of the pinnacle and backside of the PCF and covered with a gold (Au) film, and stomata are distributed around the PCF core in a progressive, periodic arrangement. Two air holes between the Au membrane and the PCF core are designed to shape a leakage window, which no longer solely averts the outward diffusion of Y-polarized (Y-POL) core mode energy, but also sets off its coupling with the Au movie from the leakage window. This SPR-PCF sensor uses the temperature-sensitive property of Polydimethylsiloxane (PDMS) to reap the motive of temperature sensing. Our lookup effects point out that these SPR-PCF sensors have a temperature sensitivity of up to 3757 pm/°C when the temperature varies from 5 °C to 45 °C. In addition, the maximum refractive index sensitivity (RIS) of the SPR-PCF sensor is as excessive as 4847 nm/RIU. These proposed SPR-PCF temperature sensors have an easy nanostructure and proper sensing performance, which now not solely improve the overall sensing performance of small-diameter fiber optic temperature sensors, but also have vast application prospects in geo-logical exploration, biological monitoring, and meteorological prediction due to their remarkable RIS and exclusive nanostructure.

Two-dimensional covalent organic frameworks (2D COFs) containing heterotriangulenes have been theoretically identified as semiconductors with tunable, Dirac-cone-like band structures, which are expected to afford high charge-carrier mobilities ideal for next-generation flexible electronics. However, few bulk syntheses of these materials have been reported, and existing synthetic methods provide limited control of network purity and morphology. Here, we report transimination reactions between benzophenone-imine-protected azatriangulenes (OTPA) and benzodithiophene dialdehydes (BDT), which afforded a new semiconducting COF network, OTPA-BDT. The COFs were prepared as both polycrystalline powders and thin films with controlled crystallite orientation. The azatriangulene nodes are readily oxidized to stable radical cations upon exposure to an appropriate p-type dopant, tris(4-bromophenyl)ammoniumyl hexachloroantimonate, after which the network's crystallinity and orientation are maintained. Oriented, hole-doped OTPA-BDT COF films exhibit electrical conductivities of up to 1.2 × 10-1 S cm-1, which are among the highest reported for imine-linked 2D COFs to date.

Photo-assist uranium extraction from fluorine-containing uranium wastewater by building semiconductor-plasma material heterostructure is a forward-looking strategy, which not only effectively accelerates F-U separation via the LSPR effect but also impacts the intensity of binding between U (VI) and site. Here, we developed an amino-rich Ag-NWs/NH2-MIL-125(Ti) (AgNW/N-M(Ti)) hybrid nanowires with LSPR effect for photo-assist uranium extraction. Accordingly, the AgNW/N-M(Ti) hybrid nanowires presented 90.4% removal efficiency for U(VI) without a sacrificial agent at the U: F molar ratio of 1:20. By virtue of In-situ KPFM, we identify hot electrons generated over AgNW were transferred to amino-rich N-M(Ti) to efficiently reduce the U(VI) adsorbed on the N-M(Ti), which effectively enhances the excellent uranium removal performance of AgNW/N-M(Ti) hybrid nanowires. This strategy may open a paradigm for the development of advanced heterojunctions with the LSPR effect as catalysts for photo-assisted uranium extraction from fluorine-containing uranium wastewater.

The surface morphology,compositions,diameters,SiC grains and phase characteristics of SiC fibers irradiated by 246.8 MeV Ar16+ions at different fluences were studied by means of field emission scanning electron microscopy(FE-SEM)and transmission electron microscopy(TEM).SEM results show that with the increase of the ion fluence,the diameter of SiC fiber first decreases and then increases.Moreover,at the highest fluence(2.7×1015 ions/cm2)irradiation,the surface rough-ness of SiC fiber increases evidently,and a brittle fracture occurred.Meanwhile,the carbon concentration on SiC fiber surface decreases and silicon concentration increases gradually with the ion fluences,accompanied by an adsorption of oxygen.TEM observations reveal that with an increase in ion fluences,the size of SiC grains first decreases and then increases,and some amorphization occurred.Furthermore,a transformation from the amorphization to the recrystallization was observed at the highest fluence irradiation.

Increasingly severe environmental pollution has spurred widespread concern regarding thermoplastics degradation. However, a lack of better understanding at the atomic level hinders the regulation of the related degradation processes. Through theoretical studies of three different typical plastics, first-principles calculations showed two basic reaction pathways for degradation: depolymerization and hydrogen-transfer-induced chain scission. The analyses of the reaction rates were consistent with those of the degradation energy barriers. Even at high temperatures, the differences in depolymerization and hydrogen transfer reactions in reaction rates and thermal perturbation probabilities are still greater than three orders of magnitude. Moreover, dynamic simulations confirm the existence of two reaction pathways and demonstrate that the two pathways occur sequentially. Our findings enrich the understanding of the basic processes of plastic degradation and may provide a reference for pyrolytic processing in waste management.

To overcome the low efficiency of traditional pyrotechnic solid-state laser energy conversion, we design a dust cloud pyrotechnic-pumped Nd :YAG laser based on the thermal radiation model and Lambert–Beer law, which effectively addresses the issue of self-absorption during the combustion of traditional pyrotechnic compositions. Therefore, the laser output energy increases significantly. A laser energy of 2.15 J with a pulse width of 50 ms is achieved using 150 mg KClO 4 /Zr/Al in this work. The energy-to-mass ratio reaches 14.34 J/g. Compared with the traditional pyrotechnic solid-state laser, the Nd :YAG laser pumped by a dust cloud showed a lower light threshold, higher energy efficiency, higher saturation limit, and better safety. In this work, we presents a novel and feasible solution for the development of compact and safe high-energy lasers.

As a common nuclide in radioactive wastewater, uranium (U) is generally treated by landfill, which induces the massive abandonment of uranium resources. In this work, a pulse voltammetry method for the synthesis of U single atoms on MoS2 (U/MoS2 ) nanosheets from radioactive wastewater for the electrocatalytic alkaline hydrogen evolution reaction (HER) is reported. The mass loading of U single atoms is facilely controlled with high selectivity for coexisting ions in radioactive wastewater. In the electrolyte of 1 m of KOH, U/MoS2 nanosheets with 5.2% of U single atoms exhibit relatively low overpotentials of 72 mV at 10 mA cm-2 . The mechanistic study reveals that the HER on U/MoS2 includes the water dissociation on U single atoms to form OH* and H transfer from OH* to adjacent S-edge atoms. This procedure exhibits decreased activation energy for transition state in water dissociation and optimized Gibbs free energy for H* adsorption.

The exploration of mandrel materials with superior degradation performance to the traditionally adopted hydrocarbon polymer of poly-α-methylstyrene (PAMS), has always been an important pursuit for fabricating high-quality inertial confinement fusion (ICF) targets. Here, we propose a method to enhance the degradation performance of mandrel material based on side-chain engineering. A series of hydrocarbon cyclic functional groups, including cyclopentane, cyclopentadiene, naphthalene and azulene, are used to replace the benzene ring on the side chain of PAMS to form new polymer structures. The results show that the degradation performance of structures can be largely regulated by different side chains. In particular, one of the naphthalene-substituted structures has similar properties to PAMS, but the required degradation condition is lower. Furthermore, the reaction rate calculations indicate that this structure is expected to be synthesized experimentally. This work provides a direction for side-chain engineering for research into the key technology of ICF target fabrication in the future.

SiC fibers were irradiated by 414.4-MeV 112 Sn 27.3+ ions to different fluences(5.0 × 10 12 ,6.0 × 10 13 , 1.6 × 10 14 , and 1.92 × 10 15 ions/cm 2 ). 112 Sn 27.3+ deposited its energy mainly via electron energy loss and passed through the SiC fiber. Then, the mechanical properties and surface characteristics of fibers were studied using a specific single filament tensile test and field emission scanning electron microscopy. Results revealed that the carbon concentration on the fiber surface increased while the silicon concentration decreased. Moreover, the addition of oxygen was found to correlate with an increase in ion fluence. Meanwhile, the fiber surface morphology of the least fluence(5.0 × 10 12 ions/cm 2 ) irradiated specimen displayed no obvious changes and its diameter was slightly reduced. With successive increases of ion fluence, large grains/bubbles on the fiber surface first appeared and then disappeared, and the diameter of fibers evidently increased.Moreover, at the highest fluence(1.92 × 10 15 Sn ions/cm 2 )irradiated specimen, some fibers were brittle fractured. As a result, the mean tensile strength and the average elastic modulus of the fibers generally decreased with respect to the ion fluence. The degradation mechanisms of mechanical properties of SiC fibers under irradiation are discussed in detail.

The energy density of aqueous supercapacitors can be enhanced by large capacitance and high operating voltage, which is mainly limited by the narrow stability window of the water. Herein, carbonaceous materials with nitrogen-doping and hierarchical porosity are successfully designed and prepared via a facile sol-gel route accompanied by the cooperative self-assembly of triblock copolymer and melamine-resorcinol-formaldehyde polymer, followed by carbonization and CO2 activation. Based on the as-prepared carbon material, symmetric supercapacitors achieve a high cell voltage of 1.8 V in 1 M Li2SO4, and exhibit a high energy density of 27.8 Wh kg(-1) at power density of 0.23 kW kg(-1). Taking advantage of the reversible redox reaction of Mn3+/Mn4+ accompanied with the insertion/extraction of Li+ of birnessite-type MnO2, the working potential of positive electrode is further expanded to 0-1.2 V (vs SCE). Then asymmetric supercapacitors with high cell voltage of 2.2 V have been successfully fabricated, exhibiting a higher energy density of 44.5 Wh kg(-1) at power density of 0.27 kW kg(-1) and an acceptable energy density of 21.8 Wh kg(-1) even at a high power density of 5.6 kW kg(-1).