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Hyperbolic metamaterials (HMMs) are artificial subwavelength-structured media that exhibit excellent hyperbolic properties. The Casimir force for HMMs can be predicted by effective medium theory (EMT), which simplifies the calculations considerably. However, the conditions of EMT in the Casimir force between HMMs have not been investigated. In this work, we compare the exact results of the Casimir force calculated by the transfer matrix method (TMM) with those from EMT. The numerical results suggest that EMT can accurately calculate the Casimir force only when the gap distance is 100 times larger than the period of a unit cell. When the gap distance and period of unit cell values are comparable, EMT is not suitable for TMM, and the main error occurs in the hyperbolic band. Furthermore, the effect of the filling ratio on the applicable conditions of EMT is also studied. This work demonstrates the conditions of EMT in calculating the Casimir force between HMMs and provides help for the development of micro- and nanoelectromechanical systems. [ABSTRACT FROM AUTHOR]

Precast ultra-high-performance concrete (UHPC) has emerged as indispensable in the engineering sector due to its cost-effectiveness and superior performance. Currently, precast UHPC grapples with challenges pertaining to slow setting times and insufficient early strength, largely attributed to its high water-reducing agent content. Effective utilization of early strength agents to augment UHPC's early strength is pivotal in addressing this issue. This study investigates the efficacy of two distinct concrete early strength agents, namely calcium formate (Ca(HCO2)2) and aluminum sulfate (Al2(SO4)3). A UHPC system with a water/cement ratio of 0.17 was used; both single and compound doping experiments were conducted using varied dosages of the aforementioned early strength agents. Our results show that both early strength agents significantly reduce setting time and enhance early strength at appropriate dosages. Specifically, the addition of 0.3% Ca(HCO2)2 led to a 33.07% decrease in setting time for UHPC. Moreover, the incorporation of 0.3% Ca(HCO2)2 and 0.5% Al2(SO4)3 resulted in a strength of 81.9 MPa at 1.5 days, representing a remarkable increase of 118.4%. It is noteworthy that excessive use of Ca(HCO2)2 inhibits the hydration process, whereas an abundance of Al2(SO4)3 diminishes the early strength effect. Simultaneously, this article provides recommendations regarding the dosage of two distinct early strength agents, offering a novel solution for expediting the production of prefabricated UHPC with a low water/cement ratio and high water-reducing agent content. [ABSTRACT FROM AUTHOR]

A sensitive extraction and instrumental method was established to detect topramezone and its metabolite (M670H05) in maize and animal-origin foods. Two years of field experiments were carried out to study the dissipation dynamics of topramezone in maize straw, and their residue levels of actual samples collected from the supermarket were determined. They were extracted using liquid–liquid extraction (LLE), and ultra-high-performance liquid chromatography–tandem mass spectrometry was used for detection. The limit of quantification was 0.005 mg kg−1. Recoveries ranged between 73.8% and 109.9% at 3 spiking levels with intraday relative standard deviation (RSD) ≤17.7% and the inter-day ≤18.1%, which meets the requirements of SANTE/12682/2019. Dissipation dynamics experiment showed that, the deposition of topramezone in maize straw in Jilin were <0.005–0.62 mg kg−1with 28 days after application. And the residue level of market samples were all less than 0.005 mg kg−1, much lower than the MRLs (range from 0.01 to 0.8 mg kg−1) set by European Union, United States Food and Drug Administration, China, and Canada. This method was effective to analyse the residues of topramezone and M670H05. [ABSTRACT FROM AUTHOR]

To explore the residual level and dietary intake risk of thifluzamide in peanut, an easy and rapid QuEChERS bases UPLC–MS/MS method was developed, and a field experiment was carried out in 9 main peanut producing areas in China. In the sample preparation process, acetonitrile was used as extractant, and PSA, C18 were used as adsorbents. The average recovery for peanut kernel and straw were between 77.8% and 100.5% with a relative standard deviation less than17.3%. The matrix matching curve showed good linearity, with the determination coefficient (R2) ≥0.9941. And the LOQ of peanut kernel and peanut straw were 0.005 mg kg–1 and 0.01 mg kg–1, respectively. The field experiment results showed that the final thifluzamide residue in the peanut straw during harvest ranged from < LOQ to 0.114 mg kg–1. For peanut kernels, the residues in Beijing, Guizhou, Shandong, Henan, Guangxi and Jilin were all lower than LOQ, while residues in Guangdong, Anhui and Hunan were detected in the range of 0.005–0.023 mgkg−1. Residues in peanut kernels were used to estimate the potential health risks of thifluzamide. The results of dietary risk of peanuts were all less than 1, which indicated that the final harvest of thifluzamide residues in peanut would not cause risk to consumers. [ABSTRACT FROM AUTHOR]

• The NF-TPV device using a periodic multilayer HM structures thermal emitter is investigated. • Two-cell structures achieve best 1.22 × 104 W/m2, surpassing CaCO 3 -InSb and hBN-lnSb structures by 2.17 and 1.12 times, respectively. • The improved performance owes credit to the strong coupling of HPhPs above the bandgap of PV cells. • The study offers a new approach to enhance the performance of NF-TPV systems. The near-field thermophotovoltaics (NF-TPV), as a solid-state energy converter, enables thermal-to-electric energy conversion efficiently due to the coupling of evanescent waves, holding great potential in waste heat recovery. Studies suggest that hyperbolic phonon polaritons (HPhPs) excited in natural hyperbolic materials (HMs) have promising prospects to improve NF-TPV performance. However, the impact of coupling of HPhPs within multilayer HM structures on NF-TPV systems remains unexplored. Here, we study an NF-TPV system in which a periodic multilayer structure composed of different HMs serves as the thermal emitter, with InSb PV cell acting as the receiver. The numerical results show that the Two-cell structure achieves an output power of 1.22 × 104 W/m2 at a temperature of 900 K, surpassing the output power of the CaCO 3 -InSb and hBN-InSb structures by 2.17 and 1.12 times, respectively. The improved performance owes credit to the strong coupling of HPhPs above the band gap of the PV cell. The study offers a new approach to enhance the performance of NF-TPV systems in waste heat recovery and the utilization of renewable energy. [ABSTRACT FROM AUTHOR]

Isotope engineering, which has received much attention for significantly reducing the optical loss of phonon polaritons, opens new doors for thermal radiation manipulation. Recent studies have shown that the shift and broadening of phonon lines caused by isotopic mass effects significantly affect near-field radiative heat transfer. Near-field thermophotovoltaics (NF-TPV) is an efficient thermal-electric energy conversion device based on radiative heat transfer at the nano/micro scale. However, the impact of isotopes on NF-TPV remains to be further studied. Here, we have theoretically studied the performance of NF-TPV systems with hBN thermal emitters of distinct isotope compositions. The numerical results show that the 98.7% 10B hBN isotope enrichment configuration reaches 67.8 kW/m2 output power and 34.7% efficiency when the emitter temperature is 900 K, surpassing the natural hBN by 8.3 kW/m2 and 1.20%. Nevertheless, the performance is suppressed in 99.2% 11B hBN structure, reduced by 1.8 kW/m2 and 0.64% compared to natural hBN. This is attributed to the isotope-induced shift and broadening of the region of hyperbolic phonon polaritons. This study can provide theoretical guidance for designing NF-TPV systems based on isotope engineering and has great application prospects in renewable energy and energy storage fields. • The impact of isotope on performances of NF-TPV systems with hBN thermal emitters is investigated. • The 98.7% 10B hBN shows the best performance (67.8 kW/m2 and 34.7%), surpassing other isotope composition devices. • The varied performance is due to the isotope-induced shift and broadening of the region of HPhPs. • This study provides theoretical guidance for designing NF-TPV systems via isotope engineering. [ABSTRACT FROM AUTHOR]

Spinning thermal radiation is a unique phenomenon in the symmetry-broken system, which is of both fundamental and applied interest. Its potential applications include chiral nanoparticle probing and radiation detection. However, these applications are often restricted by limited circular dichroism and quality factor. In this paper, the spinning thermal radiation of twisted hyperbolic heterostructures is investigated. By adjusting the twist angle, we demonstrate the near-perfect circular dichroism (CD = 0.99) and the high quality factor at a wavelength of 20 μm. The epsilon-near-zero mode of α-phase molybdenum trioxide allows for excellent spin-selective thermal radiation. The co-polarization and cross-polarization have proven it in the reflected wave and the distribution of the electric field components. The strong spinning thermal radiation originates from the cross-polarization conversion between the left-handed circularly polarized and right-handed circularly polarized waves. This work provides a general approach to spinning thermal radiation for future energy applications. [ABSTRACT FROM AUTHOR]

Recent studies have suggested that Weyl semimetals were the promising materials to verify Kirchhoff's law for nonreciprocal materials in experiment. Nevertheless, existing designs based on Weyl semimetals could not achieve perfect nonreciprocal radiation around a wavelength of 10 µm at small angles. Therefore, it is of significant importance to design structures that can realize perfect nonreciprocal radiation at a shorter wavelength and smaller angle. Here, by using attenuated total reflection, we demonstrate that perfect nonreciprocal radiation can be realized at a wavelength of 10 µm at an angle of 30°. The difference between directional emissivity and absorptivity is as large as 0.99, which is the best result until now, as far as we know. The perfect nonreciprocal radiation is attributed to the nonreciprocal guided resonances in the Weyl semimetal film, which is confirmed by the distribution of magnetic field and dispersion relation. Such a design is promising in verifying Kirchhoff's law for nonreciprocal materials in experiment. [ABSTRACT FROM AUTHOR]

This letter presents a non‐reciprocal diplexer with integrated functions of a conventional bandpass diplexer and two isolators. This is achieved by spatio‐temporally modulating the resonator frequencies in a coupled‐resonator diplexer. Due to the high channel‐to‐channel isolation, the diplexer channels can be independently modulated without affecting each other. A microstrip diplexer example is demonstrated with good agreement between the measurement and the simulation. The fabricated diplexer has two non‐reciprocal bandpass channels at 829 and 997 MHz, with a minimal insertion loss of 4.9 and 6.1 dB, and a 20‐dB isolation bandwidth of 38 and 37 MHz, respectively. To the best of the authors' knowledge, this is the first time that a non‐reciprocal diplexer has been presented. [ABSTRACT FROM AUTHOR]

Smart radiation devices (SRDs) for spacecraft, which utilize thermochromic films with adaptive emissivity switching capability and minimal resource consumption, have garnered attention. However, there remains a lack of systematic strategies for more efficient SRDs design. In this study, we focus on a typical SRD, namely VO 2 /BaF 2 /Ag, to exemplify and investigate two optimization methods: the quarter-wave condition and the traversal method. By employing the quarter-wave condition, the intermediate dielectric layer thickness required to induce Fabry-Perot resonance is determined as 1.81 μm. In this case, the emission modulation is 0.62, and the solar absorption is 0.29. However, utilizing the traversal method, optimized thicknesses for VO 2 and BaF 2 are found to be 0.02 μm and 1.60 μm, respectively. It is found that the emission modulation can reach 0.64, while the solar absorption remains unchanged at 0.29. Notably, the traversal method yields superior emission modulation of SRD compared to the quarter-wave condition, while there is no difference in solar absorption of SRD obtained by the two optimization methods. Consequently, the quarter-wave condition can provide an approximate range for the thickness of the dielectric layer in SRD designs, with further optimization achieved through the traversal method to enhance SRD performance. Overall, our research supplies valuable theoretical guidance for SRD design and aims to propel advancements in spacecraft thermal control. [ABSTRACT FROM AUTHOR]

• The HTC between α -MoO 3 films along different crystal directions is studied. • The HTC and MC are strongly related to the crystal direction. • The excitation and mismatch of HPhPs can explain the underlying physical mechanism. • This work paves novel way to design non-contact thermal modulators based on HMs. Near-field radiative heat transfer (NFRHT) has great potential in thermal management and energy harvesting due to the giant radiative heat flux. Modulation of NFRHT is another important research direction, where relative rotation between the emitter and receiver is a typical method. However, the enhancement of modulation contrast (MC) is mainly concerned in previous works, while large heat flux is not taken into account. In this work, we investigate the heat transfer coefficient (HTC) between α -MoO 3 films along different crystal directions of α -MoO 3. We take account of the modulator with high heat flux and high MC. The results show that the HTC and MC can reach 223.2 W/(m2·K) (36 times of blackbody limit) and 6.33 at a gap distance of 100 nm when NFRHT is along [010] crystal direction of α -MoO 3 , respectively. These are attributed to the excitation and mismatch of hyperbolic phonon polaritons (HPhPs). Furthermore, when NFRHT is along [100] and [001] crystal directions of α -MoO 3 , MCs reach 5.84 and 2.38, respectively. The results are strongly related to the crystal direction. In addition, the impact of film thickness on the MC for different crystal directions is investigated. This work is conducive to the applications of hyperbolic materials in non-contact thermal modulators. [ABSTRACT FROM AUTHOR]

Hyperbolic volume and surface phonon polaritons have been studied extensively for enhancing the near-field radiative heat transfer (NFRHT) between hyperbolic materials. Hyperbolic volume phonon polaritons (HVPPs) describe propagating electromagnetic waves in hyperbolic materials while evanescent waves are required for excitation of hyperbolic surface phonon polaritons (HSPPs). Therefore, the dispersion relations of HVPPs and HSPPs are distinct. Here we study the interaction of HVPPs and HSPPs within the context of NFRHT between hyperbolic materials. We find that the dispersion curves of HVPPs and HSPPs in an ultrathin hyperbolic slab can connect smoothly. Particularly, we find that the topology of HVPPs can be convex and flat, rather than concave, and can be controlled by tuning the thickness of the hyperbolic slab, which has not been reported in published literature. We believe our findings presented here may help to deepen our understanding on the interaction between HVPPs and HSPPs, as well as the knowledge on the topology of HVPPs in hyperbolic materials. [ABSTRACT FROM AUTHOR]

In this study, we established a rapid and sensitive HPLC-MS/MS method for quantitative determination of tembotrione and its metabolite AE 1417268 (M5) in corn, corn oil, beef, pork, chicken, and eggs. Both analytes eluted from a C18 column within 6 min. The electrospray ionisation–positive mode was used for tembotrione, whereas the negative mode was used for M5. Acetonitrile was the extractant for all samples, and the addition of 2 g NaCl to each homogenised sample facilitated the extraction of the analytes into acetonitrile. The extracted analytes were further purified by the addition of 50 mg of C18 sorbent (25 mg GCB was also added to corn samples) for subsequent HPLC-MS/MS analysis. Satisfactory calibration-curve linearities (R2 ≥ 0.997) were obtained for the two analytes at concentrations of 1–500 μg/L. Mean recoveries in different matrices ranged from 73.7% to 110.4%, whereas intra-day and inter-day relative standard deviations were <15% for all concentrations of spiked analytes. The limit of quantification was 2 μg/kg for each analyte in all matrices. In food samples obtained from markets, residual tembotrione and M5 were all below the limits of quantification. These results confirm that the method is suitable for the routine monitoring of residual tembotrione and M5 in a variety of food matrices. [ABSTRACT FROM AUTHOR]

In this article, we present the first demonstration of distributed and symmetrical all-band quasi-absorptive filters that can be designed to arbitrarily high orders. The proposed quasi-absorptive filter consists of a bandpass section (reflective-type coupled-line filter) and absorptive sections (a matched resistor in series with a shorted quarter-wavelength transmission line). Through a detailed analysis, we show that the absorptive sections not only eliminate out-of-band reflections but also determine the passband bandwidth (BW). As such, the bandpass section mainly determines the out-of-band roll-off and the order of the filter can be arbitrarily increased without affecting the filter BW by cascading more bandpass sections. A set of 2.45-GHz one-, two-, and three-pole quasi-absorptive microstrip bandpass filters are designed and measured. The filters show simultaneous input and output absorption across both the passband and the stopband. Measurement results agree very well with the simulation and validate the proposed design concept. [ABSTRACT FROM AUTHOR]

Many businesses possess a small infrastructure that they can use for their computing tasks, but also often buy extra computing resources from clouds. Cloud vendors such as Amazon EC2 offer two types of purchase options: on-demand and spot instances. As tenants have limited budgets to satisfy their computing needs, it is crucial for them to determine how to purchase different options and utilize them (in addition to possible self-owned instances) in a cost-effective manner while respecting their response-time targets. In this paper, we propose a framework to design policies to allocate self-owned, on-demand and spot instances to arriving jobs. In particular, we propose a near-optimal policy to determine the number of self-owned instances and an optimal policy to determine the number of on-demand instances to buy and the number of spot instances to bid for at each time unit. Our policies rely on a small number of parameters and we use an online learning technique to infer their optimal values. Through numerical simulations, we show the effectiveness of our proposed policies, in particular that they achieve a cost reduction of up to 64.51 percent when spot and on-demand instances are considered and of up to 43.74 percent when self-owned instances are considered, compared to previously proposed or intuitive policies. [ABSTRACT FROM AUTHOR]

We propose a bilayer structure made of two twisted hexagonal boron nitride (hBN) slabs for realizing tunable chirality in this work. Our numerical results show that a maximum circular dichroism as high as 0.84 can be achieved with the bilayer structure. The chiral response of the proposed structure comes from the combined effects of polarization conversion of circularly polarized wave with the top slab and selective transmission of linearly polarized wave with the bottom slab. Besides, the chirality can be actively controlled by adjusting the optic axis orientation of the top hBN slab. Finally, the bilayer structure is possible to be built with other suitable materials, metamaterials and microstructures for functioning chiral response in different wavebands. Therefore, the results in this work may provide some important hints for the design of novel chiral response sensors for optical, chemical and biological sensing. • A planar bilayer structure for realizing chiral response is proposed. • Circular dichroism (CD) as high as 0.84 is obtained with hBN. • Physical mechanisms for strong chiral response are elucidated. • Methods for realizing chiral response in different wavebands are suggested. [ABSTRACT FROM AUTHOR]

This article addresses the analysis and design of nonreciprocal filters based on time-modulated resonators. We analytically show that time modulating a resonator leads to a set of harmonic resonators composed of the unmodulated lumped elements plus a frequency-invariant element that accounts for differences in the resonant frequencies. We then demonstrate that harmonic resonators of different orders are coupled through nonreciprocal admittance inverters, whereas harmonic resonators of the same order couple with the admittance inverter coming from the unmodulated filter network. This coupling topology provides useful insights to understand and quickly design nonreciprocal filters and permits their characterization using an asynchronously tuned coupled resonators network together with the coupling matrix formalism. Two designed filters, of orders three and four, are experimentally demonstrated using quarter wavelength resonators implemented in microstrip technology and terminated by a varactor on one side. The varactors are biased using coplanar waveguides integrated into the ground plane of the device. Measured results are found to be in good agreement with numerical results, validating the proposed theory. [ABSTRACT FROM AUTHOR]

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method, in conjunction with multiwalled carbon nanotube purification, was developed to determine the mefentrifluconazole levels in grapes, cucumbers, tomatoes, peppers, wheat, maize, eggs, milk, pork, chicken, and fish. After purification, tandem mass spectrometry of mefentrifluconazole required <3.0 min. Matrix-matched external standard curves were used to quantify the residual mefentrifluconazole. The method meets the requirements of the European Union Document SANTE/11813/2017. Quantification was linear between 5 and 500 μg/kg (R2 ≥ 0.9988), and both the intra- and interday relative standard deviations were ≤13.7%. Analyte recovery ranged from 81.5% to 107.6%. The limit of mefentrifluconazole quantification was 5 μg/kg for all matrices. The method successfully detected and quantified mefentrifluconazole that had been applied to cucumbers and tomatoes grown in a test field. These results imply that the proposed method is effective and reliable for detecting mefentrifluconazole residues in plant- and animal-derived foods. [ABSTRACT FROM AUTHOR]

The transmission property of hexagonal boron nitride at its four photonic topological transitions has been studied. An interesting result is revealed that the angular optical transparency can be achieved at wavelength 12.0494 μm. The numerical results indicate that the transparency window has an angular full width at half maximum of 4° with an optical transmission higher than 0.9 at normal incidence. Besides, corresponding to an angular full width at half maximum narrower than 20°, the wavelength span is about 230 nm. These features may make the hexagonal boron nitride holds promise for applications in private screens and optical detectors. [ABSTRACT FROM AUTHOR]

Lubrication with fluid between two rough surfaces has been extensively studied, while the present work provides an additional principle for its effect on adhesive wear reduction associated with the fluid pressure. In this work, a finite element model for elastoplastic spherical contact with fluid pressure applied on surface is established, considering the realistic ductile failure criteria. It is found that as the fluid pressure increases, the location of fracture nucleation in the front contact region moves towards the contact surface. Two wear modes, namely the detaching and scratching modes, are identified by defining a critical dimensionless fluid pressure. Accordingly, the wear coefficient decreases as the fluid pressure increases, serving as the additional principle for wear reduction in lubrication systems. [Display omitted] • An additional principle for adhesive wear reduction by fluid pressure is provided. • Fracture nucleation moves towards the contact surface as fluid pressure increases. • Two wear modes and decrease of wear coefficient are observed as pressure increases. • A critical dimensionless fluid pressure is defined for a transition of wear mode. • Two approaches are suggested for further wear reduction in fluid lubrication. [ABSTRACT FROM AUTHOR]

Highlights • Studied the directional and hemispherical emissivity of hyperbolic metamaterials. • Modified the 4 × 4 matrix method to ease the numerical calculations. • Examined the effect of optic axis orientation in different hBN hyperbolic bands. • Elucidated the mechanism based on the surface impedance and admittance. • The method can be used to study the emissivity of other metamaterials. Abstract We investigate the spectral directional and hemispherical emissivity of hyperbolic metamaterials with arbitrary orientation of the optic axis. The 4 × 4 matrix method is combined with coordinate rotational transforms to circumvent projection operations. The two hyperbolic bands of hexagonal boron nitride (hBN) are examined in detail to elucidate the influence of the orientation of the optic axis on the emissivities for both transverse magnetic (TM) and transverse electric (TE) waves. The results show that the orientation of the optic axis can greatly affect the hemispherical emissivity in the two hyperbolic bands of hBN. The directional emissivity varies periodically with the azimuthal angle when TM and TE waves are coupled, resulting in conversion of polarization in the medium. For both TM and TE waves, the matching of impedance and admittance at the surface of the material is better for smaller tilting angle in the type I hyperbolic band, but the opposite is true in type II hyperbolic band where the matching becomes better for larger tilting angles. As the tilting angle increases, the hemispherical emissivity decreases in the type I hyperbolic band but increases in the type II hyperbolic band. Our conclusions can be extended to other hyperbolic materials. Therefore, this work may provide valuable guidance on characterization, measurement and tailoring of the directional and hemispherical emissivity for hBN and other hyperbolic materials with arbitrary orientation and application of such materials for manipulation of radiative heat transfer. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate, for the first time, an isolating bandpass filter with low-loss forward transmission and high reverse isolation by modulating its constituent resonators. To understand the operating principle behind the device, we develop a spectral domain analysis method and show that the same-frequency nonreciprocity is a result of the nonreciprocal frequency conversion to the intermodulation (IM) frequencies by the time-varying resonators. With appropriate modulation frequency, modulation depth, and phase delay, the signal power at the IM frequencies is converted back to the RF frequency and adds up constructively to form a low-loss forward passband, whereas they add up destructively in the reverse direction to create the isolation. To validate the theory, a lumped-element three-pole 0.04-dB ripple isolating filter with a center frequency of 200 MHz and a ripple bandwidth of 30 MHz is designed, simulated, and measured. When modulated with a sinusoidal frequency of 30 MHz, a modulation index of 0.25, and an incremental phase difference of 45°, the filter achieves a forward insertion loss of 1.5 dB and a reverse isolation of 20 dB. The measured nonmodulated and modulated results agree very well with the simulations. Such nonreciprocal filters may find applications in wideband simultaneous transmit and receive radio front ends. [ABSTRACT FROM AUTHOR]

Highlights • A QuEChERS method was modified of carboxin and its metabolites in peanuts. • Supervised field trials were conducted of carboxin in peanuts. • The total carboxin in peanut samples from fields and markets were measured. • The carboxin-exposure risk by eating peanuts was evaluated via a probabilistic model. Abstract We developed an ultra-performance liquid chromatography-tandem mass spectral method to determine the fungicide carboxin and its metabolites, oxycarboxin and carboxin sulfoxide in peanut samples. The method was used to detect the concentration of the analytes in the samples from fields and markets. The total residue quantities in peanut kernels were used to evaluate the chronic dietary risk of total carboxin upon peanut consumption. The estimated dietary intake of carboxin from peanuts whose seeds had been treated with carboxin at the recommended dose was between 0.020% and 0.344% of acceptable daily intake and the risk was found to be negligible. The chronic dietary risk assessment from markets and commercial field samples for various groups of humans indicated that the group with the greatest degree of exposure was 45 to 75-year-old women who lived in rural areas. However, their acceptable daily intake percentage was 0.006%, meaning that their health risk was extremely small. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we theoretically studied that the high extinction ratio polarizers can be designed with hexagonal boron nitride (hBN). We demonstrated that the transverse electric wave can pass the single hBN slab with high transmissivity in the range of 6.25–7.4 μm, while the transverse magnetic wave cannot pass through. The extinction ratio is always over 14 dB in that range. Besides, we also proposed a photonic crystal polarizer made of hBN and silicon, which can work in the visible band. The numerical results show that the polarizer allows the transverse magnetic wave to pass and block the transverse electric wave in the range of 0.45–0.53 μm. The minimum extinction ratio is 30 dB in this range. Therefore, we believe the low loss hBN is a promising anisotropic material for realizing polarizers and it may have applications in photography and liquid-crystal display (LCD) technology. [ABSTRACT FROM AUTHOR]

Abstract We designed an indoor mesocosm experiment to investigate the long-term effects of exposure to clomazone, a widely used herbicide, on soil microbial communities and their nitrogen (N) cycling functions. Clomazone was applied to two typical soils from China at three concentrations: 0.8 (the recommended dosage), 8 and 80 mg kg−1 soil dry weight, and the mix was incubated for 90 days. Samples were removed periodically for assay with several techniques. The half-lives of clomazone in this experiment were 11–126 d. Results were significant only for the highest clomazone concentration. Next-generation sequencing of the 16S and 18S rDNA genes revealed that bacterial diversity significantly decreased whereas fungal abundance increased after day 60 but with no detectable effect on the microbial community. Hierarchical cluster and principal coordinates analysis revealed that the bacterial community structure was negatively impacted. Linear discriminant analysis of effect size identified Sphingomonas and Arthrobacter as the predominant bacterial species. Finally, we measured soil NH 4 + and NO 3 − concentrations and used real-time PCR to analyze the abundance of the N-cycling genes , nifH and amoA. In the first 30 days, the NO 3 −-N content and the number of ammonia-oxidizing bacteria increased. N 2 -fixing bacteria were inhibited after 60 days, but the NH 4 +-N concentration remained unchanged and was likely provided by ammoniation. Graphical abstract Unlabelled Image Highlights • The effects of clomazone on soil microorganism and N 2 -cycling have been studied. • High dosage clomazone decreased bacterial abundance and changed the composition. • Clomazone could increase fungal abundance. • High dosage clomazone significantly impact the abundance of nif H and amo A. [ABSTRACT FROM AUTHOR]

Abstract The absorption of single asymmetric hyperbolic metamaterial (AHM) slab and cascaded AHM slabs has been theoretically studied in this paper. The proposed AHM consists of Polymethyl methacrylate (PMMA) and silver sheet. The numerical results show that the absorption of the single AHM slab is very sensitive to the azimuth angle, and the average absorption over the azimuth angle is only 0.2. However, the absorption of the cascaded AHM slabs can reach 0.7 in all the azimuth angles, and the average absorption over the azimuth angle can reach 0.88. Compared with the average absorption of the single AHM slab, the average absorption of the cascaded AHM slabs increases threefold. Highlights • The absorption of asymmetric hyperbolic metamaterial (AHM) has been studied. • The average absorption over the azimuth angle can reach 0.88. • The absorption of the cascaded AHM slabs can reach 0.7 in all the azimuth angles. [ABSTRACT FROM AUTHOR]

One highly conductive noble metal structure with considerable optical transparency is proposed, which is constituted by two Si slabs with a thin seamless metallic film sandwiched in the middle. The high transmission is attributed to the two resonant cavities inside the two Si slabs. The maximal transmittance of 0.98 can be achieved, and the transmittance can over 0.8 in the broad wavelength range from 0.89 to 1.37 μm. In addition, realizing considerable optical transparency for a given wavelength can be fulfilled by tuning the thickness of the Si slab. The good performance makes our structure promising for practical applications in optoelectronics. [ABSTRACT FROM AUTHOR]

In this paper, we theoretically studied that the perfect interferenceless absorption in hexagonal boron nitride can be realized at different wavenumbers and incident angles. For examples, the absorption can reach 0.999 in the wavenumber band 500–750 cm −1 when the angle of incidence is 70°, and the absorption can beyond 0.9999 in the wavenumber band 1800–2400 cm −1 when the angle of incidence is 59.5°. The orientation of the optical axis provides an active way to manipulate the optical properties of the hexagonal boron nitride. This method does not only work for hexagonal boron nitride, but also works for other anisotropic materials. The results of this paper will give us a comprehensive understanding of hexagonal boron nitride. [ABSTRACT FROM AUTHOR]

We study the relationship between the optical transition of hexagonal boron nitride and the direction of its optical axis. The results show that the optical transition can be tunable by adjusting its optical axis; therefore, it provides us an active way to control the optical transition. The reflection and transmission near the optical transition have been investigated and the results show that hexagonal boron nitride can be tuned from good reflector to transmitter or reverse. The results in this paper may help us better understand the optical transition of hexagonal boron nitride. [ABSTRACT FROM AUTHOR]

• Electrical contact resistance exists the minimum at a coating thickness. • A loading factor is proposed to fast evaluate ECR under different loading. • Wear coefficient first increases and then decreases as coating thickens increases. • Two wear modes and a critical dimensionless coating thickness are proposed. The electrically conductive coating is an effective means to reduce electrical contact resistance (ECR) of sliding electrical contact, however, the wear resistance of the coated surface influences its reliability and lifetime. The electrical contact performance of coated systems is assessed in this work using the Au-coating/Cu-substrate system. An elastic-plastic coated spherical contact is established with the realistic ductile failure criterion to allow material damage, and the effects of coating thickness and normal loading are investigated. As coating thickness increases, it is found that: the ECR decreases and then increases, presenting minimum value at a thickness independent of normal loading; the static friction coefficient increases which is related to the locations of damage occurrence at sliding inception; the wear coefficient increases to a peak and then decreases. Two wear modes of coated sliding electrical contact are observed, namely debonding mode and detaching mode, where wear particle forms by coating debonding and fracture inside coating, respectively. A critical dimensionless coating thickness, which is the minimum thickness able to protect the coating from debonding, is proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: An ultra high‐performance liquid chromatography with tandem triple quadrupole mass spectrometry residue method was developed and validated for the quantification and identification of dinotefuran and its main metabolites 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea and 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine in fruit (watermelon), vegetable (cucumber), cereal (rice), animal‐derived foods (milk, egg, and pork), soil, and water. The samples were extracted with acetonitrile containing 15% v/v acetic acid and purified with dispersive solid‐phase extraction with octadecylsilane, primary secondary amine, graphitized carbon black, or zirconia‐coated silica prior to analysis. The method had an excellent linearity (R2 ≥ 0.9942, 1–500 μg/L) and satisfactory recoveries (73–102%) at five spiked levels (0.001, 0.01, 0.05, 0.5, and 2 mg/kg) with intra‐ or interday precision in the range of 0.8–9.5% and 3.0–12.8% for the three compounds in the eight matrices. The limits of quantification were 10 μg/kg for 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine and 1 μg/kg for 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea and dinotefuran. The applicability of the developed method was demonstrated by determining the occurrence of dinotefuran, 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine, and 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea in various samples from plants, animal‐derived foods, and the environment. From 80 samples, 70 contained dinotefuran (0.8–11.7 μg/kg), among which six also contained 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea (water and rice, 0.5–0.9 μg/kg). [ABSTRACT FROM AUTHOR]

Large amounts of trifluralin are applied each year for weed control; however, its effects on soil microbial communities and functions are unknown. Two agricultural soils, one silty loam and one silty clay were spiked with TFL (0, 0.84, 8.4, and 84 mg kg –1 ) and studied the effects using a laboratory microcosm approach. The half-lives were 44.19–61.83 d in all cases. Bacterial abundance increased 1.12–5.56 times by TFL, but the diversity decreased. From the next-generation sequencing results, TFL altered the bacterial community structure, which initially diverged from the control community structure, then recovered, and then diverged again. Linear discriminant analysis effect size indicated that Sphingomonas and Xanthomonadaceae were the predominant species on day 7 and 15 in TFL treatments. N 2 -fixing bacteria were initially increased, then decreased, and then recovered, and it was positively correlated with NH 4 + -N content. Compared with the control, ammonia-oxidizing bacteria were decreased by 25.51–92.63%, ammonia-oxidizing archaea were decreased by 17.12–85.21% (except day 7), and the NO 3 − -N concentration was also inhibited. In contrast to bacteria, fungal abundance was inhibited without any observable effects on fungal diversity or community structure. These results suggest that TFL impacts soil bacterial community and alters functional microorganisms involved in soil N processing. [ABSTRACT FROM AUTHOR]

The Goos–Hanchen shifts at the surface of the tilted uniaxial crystals have been studied with the help of the stationary phase method. It is found that the permittivity and the optical axis of the uniaxial crystal have outstanding influence on the Goos–Hanchen shift. The numerical results show that the negative Goos–Hanchen shift can occur even when the refractive index of the material is not negative. Besides, the Goos–Hanchen shift can be negative or positive infinite under certain conditions. Our results may provide useful information in manipulating the Goos–Hanchen shift in uniaxial crystals. We believe this method could find practical applications in tunable sensors and switches, which are based on Goos–Hanchen shifts. [ABSTRACT FROM AUTHOR]

The wavevector of electromagnetic wave propagation in a hexagonal boron nitride (hBN) slab can be controlled by tilting its optical axis. This property can be used to manipulate the absorption in a hBN slab. By carefully analyzing the dependence of the absorptivity of a thin hBN slab on the tilted angle of its optical axis, we propose a structure that can realize great absorptivity enhancement in a band by stacking hBN slabs of different tilted angles. Our numerical results show that the absorptivity of a structure made of 91 stacked hBN slabs can be achieved higher than 0.94 in the wavenumber range from 1367 to 1580 cm −1 when the tilted angles of the slabs are properly arranged. The strong absorption is attributed to the combination of impedance matching at the slab interfaces and enlarged wavevectors in the slabs. This work reveals a novel way to realize strong absorption with anisotropic materials for applications in areas such as thermal radiative energy harvesting and conversion. [ABSTRACT FROM AUTHOR]

We propose a method to realize ultra-broadband perfect absorption by using multiple slabs of asymmetric hyperbolic metamaterial (AHM) made of doped silicon nanowire arrays. Our numerical results show that the absorptance of the structure is greater than 0.99 in the wavelength range from to for an incident transverse magnetic (TM) plane wave at an angle of incidence equal to . Moreover, the broadband absorptance can still be above 0.9 when the angle of incidence is in the range from to . The underlying mechanism is elucidated as due to the combination of matching of impedance at the interfaces and enhanced absorption in the AHM slabs of the structure. This work may provide in the design of metamaterial absorbers with some inspiring guidelines for obtaining highly enhanced absorption over an ultra-broadband and in a wide range of angle of incidence. [ABSTRACT FROM AUTHOR]

An equilibrium passive sampler based on POM was first used to determine the C free of flubendiamide in water/sediment systems. The adsorption of flubendiamide by POM followed a first-order one-compartment uptake model and the POM-water partition coefficient was 1.90. The method was used to compare the efficiency of three biochars which were produced from crofton weed (BC-1, ∼500 °C), macadamia (BC-2, 550–660 °C) and wheat straw (BC-3, 550 °C). The Freundlich fit the sorption isotherm data well and the adsorption capacity was BC-1 > BC-3 > BC-2. The percent removal of the BC-1 was higher in acidic solutions. When different doses of BC-1 were added to two sediments, the C free of the flubendiamide was higher in the sediment with a low organic matter content (S-1). With an increase of BC-1, the C free was significantly reduced in S-1. A 30-day period of biochar-sediment contact time was sufficient for a reduction of freely dissolved flubendiamide in the case of the two sediments tested. In the combination of biochar addition (5%) and aging time (30 days), the maximum reductions were 87% and 60% in S-1 and S-2. Therefore, the reduction of bioavailability of the flubendiamide and pollution repair can be achieved by this process. [ABSTRACT FROM AUTHOR]

We have developed a rapid, multi-compound analytical method for measuring residues of the pesticides thiamethoxam and its metabolite, clothianidin; fipronil and its three metabolites, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl; and pyraclostrobin in unprocessed foods (rice, corn, cucumbers, tomatoes, apples, and bananas) by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Acetonitrile was used as the extraction solvent, and an octadecylsilane-dispersive SPE was used to clean up the analytes, which were then separated through a UPLC HSS T3 column connected to a tandem mass spectrometer via an electrospray ionisation source. The linearity of this method for the target analytes was excellent (R2 ≥0.990) in the concentration range of 5–1000 μg kg–1. The average recoveries of the seven compounds at concentrations of 10, 100, and 1000 μg kg–1from six spiked matrix samples ranged from 73.6 to 110.6%, all with RSD values of ≤19.7%. The limit of quantification was 10 μg kg–1. The method validated the effectiveness of the method for routine monitoring the residue of these pesticides and their metabolites in foods. [ABSTRACT FROM PUBLISHER]

We conduct a comprehensive analysis of the eigenvalues for propagation of electromagnetic (EM) waves in anisotropic materials. The analysis can be employed to judge the characteristics of the eigenvalues for EM waves in anisotropic materials. Taking the advantage of the non-opposite eigenvalues, we show that unidirectional transmission and unidirectional invisibility can be realized with a slab of natural anisotropic material. Our results in this work may provide important guidelines for design of novel devices of unidirectional transmission or unidirectional invisibility. [ABSTRACT FROM AUTHOR]

We propose an alternative method to realize broadband high contrast ratio optical diodes based on polarization conversion between transverse electric (TE) wave and transverse magnetic (TM) wave with two slabs of uniaxial hyperbolic crystal. Taking hexagonal boron nitride as an example of the crystal, our numerical simulation results show that asymmetric transmission can occur in the wavelength range from 6.40 to 7.38 μm for incidence of a TM wave, and the transmissivity contrast ratio can be beyond 1000 in the wavelength range from 6.63 to 7.33 μm. For incidence of a TE wave, the asymmetric transmission with the transmissivity contrast ratio higher than 1000 is found in the wavelength range from 12.33 to 12.88 μm. Given that the structure is novel and simple, it may provide a promising prototype for designing high performance integrated photonic devices, such as optical logic gate and optical memory. [ABSTRACT FROM AUTHOR]

In this study, an efficient and fast method for the determination of the herbicide mesotrione and its two metabolites [4-methylsulfonyl-2-nitrobenzoic acid (MNBA) and 2-amino-4-methylsulfonylbenzoic acid (AMBA)] in rice, rice plants, rice hulls, water, and soil was developed, using ultra performance liquid chromatography coupled with tandem quadrupole (Xevo TQ-S) mass spectrometry (UPLC-Xevo TQ-S-MS/MS). The recoveries of the compounds were 68.6%–108.4% at different levels. The intra-day relative standard deviation (RSD) ranged from 2.0% to 14.4%, and the inter-day RSD, from 1.9% to 11.4%. The limits of quantification (LOQ) were ranged from 0.146 to 4.545 μg kg −1 for mesotrione, MNBA and AMBA. Dissipation and residual assays with the commercial formulation were conducted at three locations. The dissipation rates of the compounds were fast in rice plants, soil, and water, and residues at harvest were not detected in any of the three localities. [ABSTRACT FROM AUTHOR]

BACKGROUND: Grapes are highly vulnerable to infection by carbon black aspergilli, which produce ochratoxin A (OTA), a mycotoxin. Carbendazim and hymexazol are widely applied to control grape diseases. Howerver, fungicides, toxigenic fungi, and OTA can be transferred from grapes to wine causing potential safety issues. The impact of these residues on fungal populations and OTA during vinification are currently unclear. Here we investigated the effects of carbendazim and hymexazol on the viability of Aspergillus carbonarius and OTA contamination during an indoor wine‐processing experiment. RESULTS: The population size of A. carbonarius substantially increased at 24 h followed by a significantly decreased at 72 h after destemming and crushing. However, carbendazim and hymexazol notably inhibited the growth of A. carbonarius in must samples. In addition, yeast growth was substantially deleyed by carbendazim, hymexazol, and OTA during the first 3 days in compared with the control. Carbendazim, hymexazol, and OTA residues declined over time, and the processing factors (PFs) for carbendazim and hymexazol throughout vinification were 0.164, 0.074, and 0.185–0.476, respectively. Carbendazim and hymexazol each reduced OTA concentrations. However, there was no significant difference after 48 h. Addition of carbendazim or hymexazol significantly reduced the level of A. carbonarius but had no significant effect on the final concentration of OTA in mature wine. CONCLUSION: The wine‐making process can reduce the residues of OTA, carbendazim, and hymexazol in grapes, but it is recommended that grapes chosen to make wine should be free of A. carbonarius contamination. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A simple residue analytical method based on the QuEChERS approach and high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection was developed for the analysis of fipronil and its three metabolites in cottonseed, cotton plant and soil. The average recoveries of four test compounds from all three matrices were 78.6–108.9% at the level of 0.005 to 0.5 mg/kg, with an RSD in the range of 0.6 to 13.7%. The limit of quantification (LOQ) of the four test compounds ranged from 0.005 to 0.01 mg/kg. The results of the residual dynamics experiments showed that fipronil dissipated rapidly in cotton plants and soil and that oxidation and photolysis were the main degradation pathways. Moreover, the bi-exponential models demonstrated a good fit of the measured data for fipronil in cotton plants and soil, with R2 in the range of 0.8989 to 0.9989. Furthermore, a total of 40 samples of cottonseed from Shandong Province were analyzed, and all of the samples were free from the four test compound residues. [ABSTRACT FROM AUTHOR]

The singularities in the two 4 × 4 matrix formalisms have been discussed. We show that the optical degeneracies will lead to singularities in the 4 × 4 matrix formalism developed by Yeh, and the optical degeneracies will not lead to singularities in the 4 × 4 matrix formalism developed by Berreman. The main reason is that the explicit expressions of the electric fields need to be written down by hand in Yeh’s method, while the expressions of the electromagnetic fields should not be written down by hand and can be calculated by the computer directly in Berreman’s method. The discussion in this paper may help us to choose the right formalisms to do calculation. [ABSTRACT FROM AUTHOR]

The new triketone herbicide, tembotrione, provides excellent weed control in corn fields. To evaluate its safety, we established a modified QuEChERSpretreatment and ultra-high performance liquid chromatography-mass spectrometry method, using acetonitrile with 2% formic acid as the extractant and C18 as absorbent. The dissipation dynamics of tembotrionein corn straw and the terminal residual levels in all three corn matrices were studied in Henan and Jilin provinces. The linearity was excellent in the range of 0.01 to1 mg L−1, with the determination coefficient (R2) ≥0.9954. The average recovery was between 74% and 117%, with intra-day relative standard deviation less than 18.9 and the inter-day relative standard deviation less than 17.5. The degradation dynamic experiment showed that tembotrione decreased over time and followed the first-order kinetic equation. Our results showed that the regression coefficients of the dynamic equations were 0.9906 and 0.9897, with half-lives of 0.7 and 0.8 d, respectively. The final residue results showed that the maximum residues of tembotrione detected in corn in Jilin and Henan were 0.041 and 0.051 mg kg−1, respectively. The risk quotient (RQ) were calculated as 0.186 and 0.246, both of which were less than 1, which indicated an acceptable risk. [ABSTRACT FROM AUTHOR]

Highlights: [•] 100× recommended application rate reduced soil microbial activity. [•] 100× recommended application rate changed soil microbial community composition. [•] 100× recommended application rate changed microbial functional diversity. [•] Nitrogen-fixing gene abundance was reduced by high fomesafen application. [ABSTRACT FROM AUTHOR]

Highlights: [•] Bacterial growth and its gene/protein expression were detected at various concentrations of NaF. [•] Fluoride has a classic rise/fall response of inducing E. coli-GFPuv growth and gene and protein expression of GFPuv at 1mM. [•] The effect of fluoride on bacterial growth may be from regulation of mRNA expression. [•] Excessive fluoride may inhibit bacterial growth and/or disrupt its microbial balance in GI tract. [ABSTRACT FROM AUTHOR]

Highlights: [•] QuEChERS method was firstly used to extract oxathiapiprolin and its 2 metabolites. [•] UPLC–MS/MS was firstly used to determine oxathiapiprolin and its 2 metabolites. [•] Various solvents and sorbents were evaluated for the sample preparation. [•] The method exhibits acceptable recovery and high sensitivity. [•] Application of method validation showed good results. [ABSTRACT FROM AUTHOR]

Network coding allows intermediate nodes to encode data packets to improve network throughput and robustness. However, it increases the propagation speed of polluted data packets if a malicious node injects fake data packets into the network, which degrades the bandwidth efficiency greatly and leads to incorrect decoding at sinks. In this paper, insights on new mathematical relations in linear network coding are presented and a key predistribution-based tag encoding scheme KEPTE is proposed, which enables all intermediate nodes and sinks to detect the correctness of the received data packets. Furthermore, the security of KEPTE with regard to pollution attack and tag pollution attack is quantitatively analyzed. The performance of KEPTE is competitive in terms of: 1) low computational complexity; 2) the ability that all intermediate nodes and sinks detect pollution attack; 3) the ability that all intermediate nodes and sinks detect tag pollution attack; and 4) high fault-tolerance ability. To the best of our knowledge, the existing key predistribution-based schemes aiming at pollution detection can only achieve at most three points as described above. Finally, discussions on the application of KEPTE to practical network coding are also presented. [ABSTRACT FROM AUTHOR]

• The magnetophotonic crystals are proposed to realize strong nonreciprocal radiation at small angles. • The strong nonreciprocal radiation is attributed to the excitation of Tamm plasmon polaritons. • The distribution of magnetic field is studied to reveal the underlying mechanism. • The proposed structure in this work is promising to be used for verifying the Kirchhoff's law for nonreciprocal materials. Kirchhoff's law plays a vital role in radiation heat transfer, which has been recently generalized to hold for both reciprocal and nonreciprocal materials. However, the verification of the generalized Kirchhoff's law for nonreciprocal materials in experiment has not been reported. Previous proposed structures could only obtain strong nonreciprocal radiation at large angles, which were not favorable in experiment. Here, we proposed magnetophotonic crystal to realize strong nonreciprocal radiation at small angles. The numerical results show that strong nonreciprocal radiation can be obtained at angle of incidence of 30o, which is much smaller than the typical angle of 60°. The distribution of magnetic field is used to reveal the mechanism, and it indicates that the enhanced nonreciprocity is attributed to the excitation of Tamm plasmon polaritons. We believe such magnetophotonic crystal is promising in verifying the Kirchhoff's law for nonreciprocal materials. [ABSTRACT FROM AUTHOR]