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A dual-band broadband absorber based on frequency selective surface (FSS) is proposed. This double-layer absorber consists of two layers of FSS structure; each layer has a unique construction and plays its wave-absorbing function in different frequency bands. In the low-frequency band, layer I is a transmission channel, and layer II effectively absorbs electromagnetic waves. Furthermore, layer I exhibits significant absorption characteristics in the high-frequency band, whereas layer II provides effective reflection. The combination of the two layers results in a remarkably effective absorption. Its reflectivity below − 10 dB covers a bandwidth of 5.5–14.8 GHz and 22.9–33.1 GHz, and its fractional bandwidth is 128%. The structure prevents external electromagnetic interference from affecting the antenna’s performance, ensuring communication quality in critical frequency bands while reducing unwanted absorption in unwanted frequency bands. It is worth mentioning that the structure still has good stability under 45° oblique incidence. The physical mechanism is analyzed in detail by using an equivalent circuit model (ECM). The measurement results are in good agreement with those of simulation and ECM.

The simultaneous and sustainable removal of a typical heavy metal (Cr(VI)) and benzoic acid (HBA) via an FeS2/α-FeOOH/C/visible light system without consumption of extra reductive or oxidizing agents was performed to study the influence of HBA degradation on Cr(VI) reduction. The results showed that the influence order of different HBA options in accelerating Cr(VI) reduction was as follows: o-HBA > p-HBA > p-CBA > blank > m-HBA. With the addition of o-HBA, the Cr(VI) removal rate constant was increased by 1.5 times (0.047 to 0.119 min−1). Almost 100% of Cr(VI) and 70% of o-HBA were removed within 60 min under the initial Cr(VI) and o-HBA concentrations of 10 and 5 mg/L. Quenching experiments indicated that photogenerated e− and •O2− played an important role in Cr(VI) reduction, while photogenerated h+ and its derived •OH contributed to HBA degradation. Due to •O2− and •OH, separately ascribed to photogenerated e− and h+, the timely consumption of •O2− and •OH accelerated the separation and generation of photogenerated carriers, further improving light utilization efficiency and resulting in synergetic improved removal performance for both Cr(VI) and o-HBA. Theoretical calculations indicated the electron-donating ability of hydroxy groups in o-HBA was better than that in other HBA, making the activation energy for addition reaction with •OH lower. Hence, •OH would be consumed more quickly, leading to a higher promotion effect from o-HBA on Cr(VI) reduction. The real wastewater treatment experiment indicated the high applicability of synthesized FeS2/α-FeOOH/C for synergetic and sustainable removal of Cr(VI) and coexisting organic pollutants in electronic industry wastewater.

With education and communication becoming increasingly global, the need for systems that support multilingual and cross-cultural interaction is more critical than ever. Traditional robot-assisted learning platforms often fail to accommodate multiple languages, cultural diversity, or emotional and ethical dimensions of communication, limiting their effectiveness in international contexts. To address these gaps, this paper proposes the Robotic Multilingual and Cross-cultural Interactive Learning System (RM-CILS). This adaptable framework integrates social robots with natural language processing and culturally sensitive behavioral modes. RM-CILS is designed with modular capabilities for language identification and recognition, culturally aware interaction, and real-time multimodal feedback, ensuring active learner engagement and meaningful intercultural communication. The system allows students to personalize language preferences and cultural norms, thereby creating a more inclusive and relatable environment. Evaluation results demonstrate significant improvements over conventional robot-assisted systems, language coverage, a cultural adaptability index, personalization, student engagement, and learning outcome impact. By addressing learners’ mental, emotional, and ethical needs, RM-CILS establishes itself as a highly effective solution for international classrooms. It not only enhances language learning and intercultural competence but also fosters motivation, social rapport, and collaboration, making education more engaging, inclusive, and globally relevant.

Black soldier fly is a saprophagous insect that has been widely reported in recent years due to its excellent performance in bioremediation. Due to the widespread presence of flocculants in the organic waste treated by black soldier fly larvae, this study aimed to evaluate the potential impacts and risks of flocculant addition (a combination of poly aluminum chloride and polyacrylamide with the ratio of 50:1). Results showed that the growth and weight of BSFL in the high-exposure groups (≥200 mg/L) were inhibited. The bioaccumulation of aluminum (Al) in larvae was estimated, and the proportions of different Al forms in the frass from high to low were the residual state (41.38% to 67.92%), water-soluble state (16.88% to 37.03%), acid-soluble state (8.45% to 18.72%), and alkali-soluble state (3.38% to 5.14%). The relative abundance of bacterial genera related to lipid metabolism decreased with increasing flocculant concentrations while disease-related taxa increased in relative abundance. The results serve as a reference for subsequent research and application of the treatment of flocculant-contaminated waste by BSFL.

Although AI technology has been widely utilized in many fields and has reaped good reviews. However, there is a vacancy in the education field for AI technology to achieve personalized recommendations for the English language. In this paper, based on the traditional cognitive diagnostic model, we propose optimizing two aspects, namely question type and mastery state. Combining the neighborhood recommendation algorithm, the English learning recommendation model is constructed using fuzzy cognitive diagnosis. Based on the theory of adaptive learning, we have designed a personalized bank of recommended English learning questions. The model is utilized in the real world of English learning, and a control experiment is designed to evaluate the student’s knowledge mastery and the impact of the model application. The experiment shows that student A has a better mastery of S1 and S3, with mastery levels of 0.856 and 0.815, respectively, but only 0.235 for S4, and needs to customize a more targeted personalized learning plan and strategy for S4-related content. The average scores of D1 and D2 before practice were 73.51 and 72.18, and after practicing through the personalized recommending English learning methods proposed in this paper, the English score of the D2 class was improved to 85.33, and the t-test result between the two groups was significant p-value of 0.002, which is less than 0.01, indicating that there is a significant difference between the two groups and that the model proposed in this paper has a significant enhancement on English learning.

In order to efficiently remove NOMs in natural surface water and alleviate membrane pollution at the same time, a flat microfiltration ceramic membrane (CM) was modified with MnFeOX (Mn-Fe-CM), and a coagulation–precipitation–sand filtration pretreatment coupled with an in situ ozonation-ceramic membrane filtration system (Pretreatment/O3/Mn-Fe-CM) was constructed for this study. The results show that the removal rates of dissolved organic carbon (DOC), specific ultraviolet absorption (SUVA) and NH4+-N by the Pretreatment/O3/Mn-Fe-CM system were 51.1%, 67.9% and 65.71%, respectively. Macromolecular organic compounds such as aromatic proteins and soluble microbial products (SMPs) were also effectively removed. The working time of the membrane was about twice that in the Pretreatment/CM system without the in situ ozone oxidation, which was measured by the change in transmembrane pressure, proving that membrane fouling was significantly reduced. Finally, based on the SEM, AFM and other characterization results, it was concluded that the main mitigation mechanisms of membrane fouling in the Pretreatment/O3/Mn-Fe-CM system was as follows: (1) pretreatment could remove part of DOC and SUVA to reduce their subsequent entrapment on a membrane surface; (2) a certain amount of shear force generated by O3 aeration can reduce the adhesion of pollutants; (3) the loaded MnFeOX with a higher catalytic ability produced a smoother active layer on the surface of the ceramic membrane, which was conducive in reducing the contact among Mn-Fe-CM, O3 and pollutants, thus increasing the proportion of reversible pollution and further reducing the adhesion of pollutants; (4) Mn-Fe-CM catalyzed O3 to produce ·OH to degrade the pollutants adsorbed on the membrane surface into smaller molecular organic matter, which enabled them pass through the membrane pores, reducing their accumulation on the membrane surface.

In order to improve the production efficiency of volatile fatty acids (VFAs) by anaerobic fermentation of food waste and reduce the cost for the production of organic deicing salt (ODS), ceramic microfiltration (MF) membrane separation was applied in the conventional food waste fermenter to build an anaerobic membrane bioreactor (AnMBR). Results showed that the maximum VFA concentration in AnMBR was up to 55.37 g/L. Due to the fact that the MF membrane could realize in situ separation of VFAs, the recovery of VFAs could reach 95.0%; 66.6% higher than that of traditional fermentation reactors. After the application of the MF membrane, more than 20.0% of soluble COD, 40.0% of proteins, and 50.0% of polysaccharides were retained and more than 90.0% of VFAs could be transferred in a timely fashion in the AnMBR system. In addition, the enrichment effect of the MF membrane enhanced enzymatic activities such as protease, α-Glucosidase and acetate kinase, and increased the abundance of some important bacteria for organic acid generation such as Amphibacter, Peptoniphilus and Halomonas, which made a significant contribution to the yield of VFAs. After concentration, evaporation and crystallization, the melting efficiency of obtained ODS can reach more than 90.0% in chloride salts, which was 112.0% of commercial calcium magnesium acetate (CMA). When compared to chloride salts and CMA, ODS was more environmentally-friendly as it can reduce the corrosion of carbon steel and concrete significantly. This study created a new way of converting food waste into a high-value organic deicing agent, realizing the resource utilization of solid waste and reducing the production cost of organic deicing agents.

Piezoelectric materials allow conversion between electricity and mechanical stresses. The most efficient piezoelectric materials are ceramics such as BaTiO 3 or PbZrO 3 , which are also extremely stiff. You et al. identified an organic perovskite structured piezoelectric material that is far more pliable yet has a piezoelectric response similar to that of traditional ceramics. This material may be a better option to use as a mechanical sensor for flexible devices, soft robotics, biomedical devices, and other micromechanical applications that benefit from a less stiff piezoelectric material. Science , this issue p. 306 Trimethylchloromethyl ammonium trichloromanganese(II) may be a flexible material competitive for piezoelectric applications. Molecular piezoelectrics are highly desirable for their easy and environment-friendly processing, light weight, low processing temperature, and mechanical flexibility. However, although 136 years have passed since the discovery in 1880 of the piezoelectric effect, molecular piezoelectrics with a piezoelectric coefficient d 33 comparable with piezoceramics such as barium titanate (BTO; ~190 picocoulombs per newton) have not been found. We show that trimethylchloromethyl ammonium trichloromanganese(II), an organic-inorganic perovskite ferroelectric crystal processed from aqueous solution, has a large d 33 of 185 picocoulombs per newton and a high phase-transition temperature of 406 kelvin (K) (16 K above that of BTO). This makes it a competitive candidate for medical, micromechanical, and biomechanical applications.

Fermentative kitchen waste to produce high-value chemicals (e.g., acetic acid) has been investigated actively in the past decades. Creating an alkaline condition is widely used to improve the hydrolysis of polysaccharide and inhibit the methanogenesis, but this method significantly increases the overall cost. Herein, the present study investigated the bioaugmentation with rumen fluid to improve acetic acid production from kitchen waste at neutral condition via strengthening hydrolytic and acid-forming bacteria. Results showed that the highest acetic acid yield reached 1.52 g/L at rumen fluid and granular sludge ratio of 1:1. The proportion of acetic acid in volatile fatty acids (VFAs) has increased by 10% compared to control. Microbial community analysis revealed that bioaugmentation with rumen fluid increased the relative abundance of Prevotella and Rikenellaceae_RC9_gut_group which has the ability to degrade polysaccharides and produce acetic acid. Moreover, the proliferation of butyric acid producers (Clostridium_sensu_stricto_1 and Clostridium_sensu_stricto_7) were inhibited significantly, which was in agreement with high acetic acid proportion in VFAs. The bioaugmentation strategy and process optimization provided an energy and cost-saving method for acetic acid production from kitchen waste.

Humic acids (HAs) produced during the landfill on Cr(VI) fate and their combined impact on the anaerobic digestion (AD) process has not yet been fully elucidated. This study systematically evaluated the interactions and mechanism of HAs on the AD of Cr(VI)-contaminated leachate. Results indicated that high concentrations of HAs (i.e., 200, 500, 1000 mg/L) detoxified the Cr(VI) on AD and the maximum methane production of 1011.63 ± 248.01 mL/g COD was obtained at 500 mg/L HAs, representing an 18.4% increase compared to the control group. Mechanistic studies demonstrated that high concentrations of HAs (i.e., C4-C5) detoxified the Cr(VI) on AD via adsorption and reduction, and the enhanced direct interspecies electron transfer (DIET) played an important role in methane production. The adsorption capacity (32.89 mg Cr(VI)/g HAs) was significantly higher than the granular sludge (3.29 mg Cr(VI)/g TS) and adsorbed Cr(VI) was reduced to less toxic Cr(III) due to the presence of functional groups of HAs (e.g., hydroxyl and phenolic groups), achieving detoxification of Cr(VI) on AD. The increase of viable microbial cells proved the detoxification of high HAs concentrations. Moreover, the increase in the abundance of Syntrophomonas and Methanosaeta has led to the higher methane production at high HAs concentration.