The preparation of carbon-based electromagnetic wave(EMW) absorbers possessing thin matching thickness, wide absorption bandwidth, strong absorption intensity, and low filling ratio remains a huge challenge. Metal–...
The preparation of carbon-based electromagnetic wave(EMW) absorbers possessing thin matching thickness, wide absorption bandwidth, strong absorption intensity, and low filling ratio remains a huge challenge. Metal–organic frameworks(MOFs) are ideal selfsacrificing templates for the construction of carbon-based EMW absorbers. In this work, bimetallic FeMn–MOF-derived Mn Fe2O4/C/graphene composites were fabricated via a two-step route of solvothermal reaction and the following pyrolysis treatment. The results reveal the evolution of the microscopic morphology of carbon skeletons from loofah-like to octahedral and then to polyhedron and pomegranate after the adjustment of the Fe3+to Mn2+molar ratio. Furthermore, at the Fe3+to Mn2+molar ratio of 2:1, the obtained MnFe2O4/C/graphene composite exhibited the highest EMW absorption capacity. Specifically, a minimum reflection loss of-72.7 dB and a maximum effective absorption bandwidth of 5.1 GHz were achieved at a low filling ratio of 10wt%. In addition, the possible EMW absorption mechanism of Mn Fe2O4/C/graphene composites was proposed. Therefore, the results of this work will contribute to the construction of broadband and efficient carbon-based EMW absorbers derived from MOFs.
The efficient separation of fission products,such as TcO4-and I-,holds strategic significance for the management of radioactive wastes and environmental *** this study,we propose an ultrafast strategy for scalable pre...
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The efficient separation of fission products,such as TcO4-and I-,holds strategic significance for the management of radioactive wastes and environmental *** this study,we propose an ultrafast strategy for scalable preparation of a highly quaternized organic network to facilitate efficient and synchronous separation of iodide and *** network can be prepared within a few minutes at room temperature,using polyethylenimine and 1,2,4,5-tetrakis(bromomethyl)benzene as building *** chlorine replacement,the network,abundantly decorated with quaternary ammonium groups (Cl@QPN),exhibits an ultrahigh positive charge density of 7.6 mmol/*** enables the rapid and efficient enrichment of target anions through strong electrostatic Coulomb *** a result,Cl@QPN exhibits significantly higher adsorption rate constants of 0.830 g/(mg min) for ReO4-(a nonradioactive surrogate of TcO4-) and 0.677 g/(mg min) for I-compared to other ***,it possesses high adsorption capacities,reaching 1,681 mg/g for ReO4-and 917.4 mg/g for I-.Cl@QPN also demonstrates good selectivity towards target ions and shows efficient adsorption for99TcO4-.Additionally,Cl@QPN exhibits high dynamic processing capacities,handling up to 3,100 and 7,400 kg of simulated streams per kilogram of material for I-and ReO4-,respectively.
A robust Reynolds-Averaged Navier-Stokes(RANS) based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC) rotor. The complex motion with multiple degrees of...
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A robust Reynolds-Averaged Navier-Stokes(RANS) based solver is established to predict the complex unsteady aerodynamic characteristics of the Active Flap Control(AFC) rotor. The complex motion with multiple degrees of freedom of the Trailing Edge Flap(TEF) is analyzed by employing an inverse nested overset grid method. Simulation of non-rotational and rotational modes of blade motion are carried out to investigate the formation and development of TEF shedding vortex with high-frequency deflection of TEF. Moreover, the mechanism of TEF deflection interference with blade tip vortex and overall rotor aerodynamics is also explored. In nonrotational mode, two bundles of vortices form at the gap ends of TEF and the main blade and merge into a single TEF vortex. Dynamic deflection of the TEF significantly interferes with the blade tip vortex. The position of the blade tip vortex consistently changes, and its frequency is directly related to the frequency of TEF deflection. In rotational mode, the tip vortex forms a helical structure. The end vortices at the gap sides co-swirl and subsequently merge into the concentrated beam of tip vortices, causing fluctuations in the vorticity and axial position of the tip vortex under the rotor. This research concludes with the investigation on suppression of Blade Vortex Interaction(BVI), showing an increase in miss distance and reduction in the vorticity of tip vortex through TEF phase control at a particular control frequency. Through this mechanism, a designed TEF deflection law increases the miss distance by 34.7% and reduces vorticity by 11.9% at the target position,demonstrating the effectiveness of AFC in mitigating BVI.
Photovoltaic metal halide perovskite solar cells(PSCs) convert light to electricity more efficiently than crystalline silicon cells, and the cost of materials used to make them is lower than that of silicon *** effici...
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Photovoltaic metal halide perovskite solar cells(PSCs) convert light to electricity more efficiently than crystalline silicon cells, and the cost of materials used to make them is lower than that of silicon *** efficiency is not a core issue affecting the application of perovskite solar cells in special *** present, stability is the major technical encounters that hinders its further commercial development. Microstrain in PSCs is currently a significant factor responsible for the device's instability. Strain-induced ion migration is widely believed to accelerate perovskite degradation even when external stimuli are ***, it is imperative to study strain to enhance the stability of PSCs. This paper reviews recent developments to understand strain's origin and effect mechanisms on performance of PSCs, including ion migration,failure behavior, defect formation, and its effect on photoelectric properties, stability, and ***, several well-known strain management strategies are systematically introduced based on the strain effect mechanism and strain engineering on the film, providing more clues for further preparation with increased stability. The manipulation of external physical strain applied from films to entire devices has been extensively studied. Furthermore, recommendations for future research directions and chemical approaches have been provided. It is emphasized that strain engineering plays a crucial role in improving the efficiency and longevity of PSCs. Tensile strain causes rapid degradation, while moderate compressive strain and external strain control could improve properties and stability. Efforts should focus on controlling compressive strain to mitigate residual tensile strain and introducing it in a controlled manner. Future research endeavors may focus on exploring these pathways to improve the efficiency and lifespan of PSCs.
The phenomenon of induced transparency, characterized by a high quality(Q) factor, holds significant importance in the fields of high-precision sensing, energy storage and wave manipulation. Conventional transparency ...
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The phenomenon of induced transparency, characterized by a high quality(Q) factor, holds significant importance in the fields of high-precision sensing, energy storage and wave manipulation. Conventional transparency systems are often constrained by the limited experimentally accessible parameter space and the lack of independent control over intrinsic parameters, thereby hindering advanced research on high-Q effects. Here we propose a virtualized coupled-oscillator system that enables reconfigurable induced transparency in the reflection spectrum. By virtually incorporating a pair of coupled oscillators into an individual acoustic meta-atom, we achieve the manipulation of induced transparency in a decoupled, wide-ranging, and elaborate manner. Exploiting the diverse evolutions across the intrinsic parameter space, we show experimentally a counter-intuitive increase in the Q-factor of the transparency window, which is attributed to the enhanced dissipation of the bright ***, a constant group delay at the center frequency is observed accompanying this evolution. Our work demonstrates an intriguing platform as well as a novel strategy to engineer high-Q induced transparency phenomenon, and paves the way towards applications in programmable acoustic sensors, filters and slow-wave devices.
An ever-increasing market demand has stimulated the soaring enthusiasm of researchers to develop wide-temperature supercapacitors(SCs). The active electrode is one of the most important parts of SC, which is directly ...
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An ever-increasing market demand has stimulated the soaring enthusiasm of researchers to develop wide-temperature supercapacitors(SCs). The active electrode is one of the most important parts of SC, which is directly related to the energy density,power transmission and long-term cyclability of the device in the wide-temperature environment. Compared with the SC electrodes aimed for room-temperature application, the SC electrodes for operating at wide-temperature scene often face greater challenges. In this review, the main challenges of SC electrodes under various temperature conditions, including low, high and cross-fade temperatures, are summarized. The relevant performance decay and failure mechanisms of wide-temperature SC electrodes are analyzed. In addition, this review deals with the recent studies and developments in robust wide-temperature SC electrodes with respect to the rational design of electrode structures and the exploitation of advanced active materials. Finally, the future directions for exploring reliable wide-temperature SCs are also proposed.
Under the assumption of integral m-Bakry-émery Ricci curvature, we give an Escobar-LichnerowiczReilly type eigenvalue estimate for the weighted p-Laplacian on compact smooth metric measure spaces with or without boun...
Under the assumption of integral m-Bakry-émery Ricci curvature, we give an Escobar-LichnerowiczReilly type eigenvalue estimate for the weighted p-Laplacian on compact smooth metric measure spaces with or without boundaries. This conclusion is a generalization and improvement of Wang-Li’s result in the case of integral Bakry-émery Ricci curvature, and of Seto-Wei’s one to the compact metric measure space setting. Our main tools are the weighted p-Bochner formula and the weighted p-Reilly formula.
Objective To examine the effectiveness of Chinese medicine(CM)Lianhua Qingwen Granule(LHQW)and Jingyin Gubiao Prescription(JYGB)in asymptomatic or mild patients with Omicron infection in the shelter *** This single-ce...
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Objective To examine the effectiveness of Chinese medicine(CM)Lianhua Qingwen Granule(LHQW)and Jingyin Gubiao Prescription(JYGB)in asymptomatic or mild patients with Omicron infection in the shelter *** This single-center retrospective cohort study was conducted in the largest shelter hospital in Shanghai,China,from April 10,2022 to May 30,2022.A total of 56,244 asymptomatic and mild Omicron cases were included and divided into 4 groups,i.e.,non-administration group(23,702 cases),LHQW group(11,576 cases),JYGB group(12,112 cases),and dual combination of LHQW and JYGB group(8,854 cases).The length of stay(LOS)in the hospital was used to assess the effectiveness of LHQW and JYGB treatment on Omicron *** Patients aged 41–60 years,with nadir threshold cycle(CT)value of N gene<25,or those fully vaccinated preferred to receive CM *** or after propensity score matching(PSM),the multiple linear regression showed that LHQW and JYGB treatment were independent influence factors of LOS(both P<0.001).After PSM,there were significant differences in LOS between the LHQW/JYGB combination and the other groups(P<0.01).The results of factorial design ANOVA proved that the LHQW/JYGB combination therapy synergistically shortened LOS(P=0.032).Conclusions Patients with a nadir CT value<25 were more likely to accept *** LHQW/JYGB combination therapy could shorten the LOS of Omicron-infected individuals in an isolated environment.
The essential photoprotective role of proton gradient regulation 5(PGR5)-dependent cyclic electron flow(CEF)has been reported in Arabidopsis,rice,and ***,its functional assessment has not been performed in tomato *** ...
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The essential photoprotective role of proton gradient regulation 5(PGR5)-dependent cyclic electron flow(CEF)has been reported in Arabidopsis,rice,and ***,its functional assessment has not been performed in tomato *** this study,we focused on elucidate the function of SlPGR5 and SlPGR5-like photosynthetic phenotype 1(PGRL1)in *** performed RNA interference and found that SlPGR5/SlPGRL1-suppressed transformants exhibited extremely low CO_(2)assimilation capacity,their photosystem I(PSI)and PSII were severely photoinhibited and chloroplasts were obviously *** SlPGR5/SlPGRL1-suppressed plants almost completely inhibited CEF and Y(ND),and PSII photoinhibition may be directly related to the inability to produce sufficient proton motive force to induce *** transgenic plants overexpressing SlPGR5 and SlPGRL1 driven by 35S promoter capable alleviate photoinhibition of plants under low night *** transcriptomic and proteomic analyses suggested that the nuclear gene transcription and turnover of chloroplast proteins,including the plastoglobule-related proteins,were closely related to SlPGR5/SlPGRL1 pathway dependent *** bridge relationship between CEF and chloroplast quality maintenance was a novel report to our *** conclusion,these results revealed the regulatory mechanism of the SlPGR5/SlPGRL1 pathway in photoprotection and maintenance of chloroplast function in tomato,which is crucial for reduce yield loss,especially under adverse environmental conditions.
The water content of cut flowers is a significant factor in their post-harvest *** this study,we examine the efficacy of silver nanoparticles(NS)on the longevity of cut gladiolus,with a focus on water state and *** us...
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The water content of cut flowers is a significant factor in their post-harvest *** this study,we examine the efficacy of silver nanoparticles(NS)on the longevity of cut gladiolus,with a focus on water state and *** used Low-field nuclear magnetic resonance(LF-NMR)technology to identify three water fractions with different transverse relaxation times(T2)values:bound water T21(10 ms).During the opening process,T23increased at stages 2 and 3 and then decreased,T22 decreased slowly,and T21 remained *** water values were consistently higher than bound water and immobilized water and reached their maximum from stage 2 until stage 4,when the petals were extended and began to *** vascular bundles responsible for transporting water had higher water content,as detected by proton density-weighted magnetic resonance imaging(MRI).Bound water and free water with NS pretreatments in bracts were initially lower but then two days later the signal amplitude of each water state exceeded those of the control,indicating that the treatment enhanced the water-holding capacity over ***,NS pretreatments reduced the free water mobility of the cut flowers and inhibited stem ***,we found that NS can enter the stem and are primarily transported upward along the xylem with water using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)***,our findings indicate that NS pretreatment reduces free water in gladiolus cut flowers,enhancing their water retention and prolonging their vase life.
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