Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 93
Filtrar
1.
Adv Sci (Weinh) ; : e2400967, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38626379

RESUMO

Recently, the altermagnetic materials with spin splitting effect (SSE), have drawn significant attention due to their potential to the flexible control of the spin polarization by the Néel vector. Here, the direct and inverse altermagnetic SSE (ASSE) in the (101)-oriented RuO2 film with the tilted Néel vector are reported. First, the spin torque along the x-, y-, and z-axis is detected from the spin torque-induced ferromagnetic resonance (ST-FMR), and the z-spin torque emerges when the electric current is along the [010] direction, showing the anisotropic spin splitting of RuO2. Further, the current-induced modulation of damping is used to quantify the damping-like torque efficiency (ξDL) in RuO2/Py, and an anisotropic ξDL is obtained and maximized for the current along the [010] direction, which increases with the reduction of the temperature, indicating the present of ASSE. Next, by way of spin pumping measurement, the inverse altermagnetic spin splitting effect (IASSE) is studied, which also shows a crystal direction-dependent anisotropic behavior and temperature-dependent behavior. This work gives a comprehensive study of the direct and inverse ASSE effects in the altermagnetic RuO2, inspiring future altermagnetic materials and devices with flexible control of spin polarization.

2.
Int J Biol Macromol ; 268(Pt 1): 131618, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38631593

RESUMO

This study aims to fabricate composite gels using nano citrus fiber (Nano-CF) derived from the hydrolysis process of citric acid (CA) with FeCl3, with a simultaneous exploration of its potential as an substitute to fats. Investigation of varying FeCl3 concentrations (0.01 to 0.03 mmol/g of CA) revealed a significant enhancement in the water-holding and oil-retention capacity of the Nano-CF. The meticulous synthesis of the composite gels involved integrating nano citrus fibers with konjac glucomannan (KGM) through high-speed shearing, followed by a comprehensive evaluation of its microstructure and physicochemical attributes. Increasing the Nano-CF concentration within the gels led to a synergistic interaction with KGM, resulting in enhanced viscosity, improved thermal stability, and restricted water molecule mobility within the system. The gels initially displayed reduced firmness, resilience, and adhesive characteristics, followed by subsequent improvement. When the ratio of Nano-CF to KGM was 0.5:1, the composite gels exhibited texture parameters, viscosity, and viscoelastic stability comparable to whipped animal cream formulations. These findings provide a new idea for the application of Nano-CF/KGM composite gels in whipped cream.

3.
Adv Sci (Weinh) ; : e2308716, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38502884

RESUMO

Advancing the development of point-of-care testing (POCT) sensors that utilize interstitial fluid (ISF) presents considerable obstacles in terms of rapid sampling and analysis. Herein, an innovative strategy is introduced that involves the use of a 3D-printed, hollow microneedle array patch (MAP), in tandem with a vacuum tube (VT) connected through a hose, to improve ISF extraction efficiency and facilitate expedited analysis. The employment of negative pressure by the VT allows the MAP device to effectively gather ≈18 µL of ISF from the dermis of a live rabbit ear within a concise period of 5 min. This methodology enables the immediate and minimally invasive measurement of glucose levels within the body, employing personal healthcare meters for quantification. The fusion of the VT and MAP technologies provides for their effortless integration into a comprehensive and mobile system for ISF analysis, accomplished by preloading the hose with custom sensing papers designed to detect specific analytes. Moreover, the design and functionality of this integrated VT-MAP system are intuitively user-friendly, eliminating the requirement for specialized medical expertise. This feature enhances its potential to make a significant impact on the field of decentralized personal healthcare.

4.
Huan Jing Ke Xue ; 45(2): 1185-1195, 2024 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-38471955

RESUMO

Microplastics are an emerging contaminant that can persist in the environment for extended periods, posing risks to ecological systems. Recently, microplastic pollution has emerged as a major global environmental problem. In order to ensure accurate and scientific evaluation of the ecological risks associated with microplastic pollution, it is of paramount importance to improve the simplicity and reliability of microplastic identification, systematically analyze the pollution characteristics of microplastics in various environmental media, and clarify their environmental impacts. Machine learning technology has gained widespread attention in microplastic research by learning and analyzing large volumes of data to establish result evaluation or prediction models. The use of machine learning can enhance the automation and identification efficiency of visual and spectral identification of microplastics, provide scientific support for tracing the sources of microplastic pollution, and help reveal the complex environmental effects of microplastics. This review provides a summary of the application characteristics and limitations of machine learning in the aforementioned areas by reviewing the progress made in research that employs machine learning technology in microplastic identification and environmental risk assessment. Furthermore, the findings of the review will provide suggestions and prospects for the development and application of machine learning in related areas.

5.
Nat Commun ; 15(1): 2077, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453947

RESUMO

Ultrastrong and deep-strong coupling are two coupling regimes rich in intriguing physical phenomena. Recently, hybrid magnonic systems have emerged as promising candidates for exploring these regimes, owing to their unique advantages in quantum engineering. However, because of the relatively weak coupling between magnons and other quasiparticles, ultrastrong coupling is predominantly realized at cryogenic temperatures, while deep-strong coupling remains to be explored. In our work, we achieve both theoretical and experimental realization of room-temperature ultrastrong magnon-magnon coupling in synthetic antiferromagnets with intrinsic asymmetry of magnetic anisotropy. Unlike most ultrastrong coupling systems, where the counter-rotating coupling strength g2 is strictly equal to the co-rotating coupling strength g1, our systems allow for highly tunable g1 and g2. This high degree of freedom also enables the realization of normalized g1 or g2 larger than 0.5. Particularly, our experimental findings reveal that the maximum observed g1 is nearly identical to the bare frequency, with g1/ω0 = 0.963, indicating a close realization of deep-strong coupling within our hybrid magnonic systems. Our results highlight synthetic antiferromagnets as platforms for exploring unconventional ultrastrong and even deep-strong coupling regimes, facilitating the further exploration of quantum phenomena.

6.
RSC Adv ; 14(5): 3611-3616, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38264269

RESUMO

Typical small organic dyes exhibit excellent UV absorption capabilities and are commonly used as additives to shield plastic films from photoaging. However, their tendency to decompose easily and migrate rapidly within a polymer matrix limits their service life. Herein we prepared g-C3N4 nanosheets and fabricated g-C3N4/PBAT films to investigate the effects of g-C3N4 on UV shielding and plasticizing of a biodegradable PBAT film. Photophysical characterizations revealed that an improved UV light barrier performance was achieved on g-C3N4/PBAT films compared to pure PBAT. Furthermore, the photoaging results show that g-C3N4 can stably exist in the PBAT matrix, enabling the aged g-C3N4/PBAT films to maintain their effective UV shielding ability, whereas the aged benzophenone (UV-0)/PBAT film shows a substantial decrease in UV light absorption due to the photodecomposition of UV-0. Additionally, g-C3N4 acted as a reinforcing material for PBAT, as evidenced by the approximately 1.5-fold increase in longitudinal tear strength and 1.6-fold increase in tensile strength of g-C3N4/PBAT films compared to pure PBAT. Remarkably, even after 100 hours of photoaging, the aged g-C3N4/PBAT films retained their favorable mechanical properties. This study highlights the potential of g-C3N4 as a new type of UV shield additive for future practical applications in protecting biodegradable plastic from photoaging.

7.
Sci Adv ; 10(2): eadk7935, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38215195

RESUMO

The intrinsic fast dynamics make antiferromagnetic spintronics a promising avenue for faster data processing. Ultrafast antiferromagnetic resonance-generated spin current provides valuable access to antiferromagnetic spin dynamics. However, the inverse effect, spin-torque-driven antiferromagnetic resonance (ST-AFMR), which is attractive for practical utilization of fast devices but seriously impeded by difficulties in controlling and detecting Néel vectors, remains elusive. We observe ST-AFMR in Y3Fe5O12/α-Fe2O3/Pt at room temperature. The Néel vector oscillates and contributes to voltage signal owing to antiferromagnetic negative spin Hall magnetoresistance-induced spin rectification effect, which has the opposite sign to ferromagnets. The Néel vector in antiferromagnetic α-Fe2O3 is strongly coupled to the magnetization in Y3Fe5O12 buffer, resulting in the convenient control of Néel vectors. ST-AFMR experiment is bolstered by micromagnetic simulations, where both the Néel vector and the canted moment of α-Fe2O3 are in elliptic resonance. These findings shed light on the spin current-induced dynamics in antiferromagnets and represent a step toward electrically controlled antiferromagnetic terahertz emitters.

8.
Small ; : e2308724, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38229571

RESUMO

In future information storage and processing, magnonics is one of the most promising candidates to replace traditional microelectronics. Yttrium iron garnet (YIG) films with perpendicular magnetic anisotropy (PMA) have aroused widespread interest in magnonics. Obtaining strong PMA in a thick YIG film with a small lattice mismatch (η) has been fascinating but challenging. Here, a novel strategy is proposed to reduce the required minimum strain value for producing PMA and increase the maximum thickness for maintaining PMA in YIG films by slight oxygen deficiency. Strong PMA is achieved in the YIG film with an η of only 0.4% and a film thickness up to 60 nm, representing the strongest PMA for such a small η reported so far. Combining transmission electron microscopy analyses, magnetic measurements, and a theoretical model, it is demonstrated that the enhancement of PMA physically originates from the reduction of saturation magnetization and the increase of magnetostriction coefficient induced by oxygen deficiency. The Gilbert damping values of the 60-nm-thick YIG films with PMA are on the order of 10-4 . This strategy improves the flexibility for the practical applications of YIG-based magnonic devices and provides promising insights for the theoretical understanding and the experimental enhancement of PMA in garnet films.

9.
J Hazard Mater ; 465: 133472, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38219587

RESUMO

Microplastic pollution, a major global concern, has garnered increasing attention in agricultural ecosystem research. China's Hetao Irrigation District, vital for grain production in the Yellow River Basin, lacks sufficient research on microplastic pollution of agricultural soils. This study, based on a detailed background investigation and testing of 47 samples, is the first to elucidate the characteristics and potential influencing factors of microplastics in the Hetao Irrigation District. The abundance of microplastics in the farmland soil ranged from 1810 to 86331 items/kg, with 90% measuring below 180 µm and mainly in film and fragment forms. Predominant polymers were polyethylene (PE, 43.0%) and polyamide (PA, 27.8%). Key pollution influencers were identified as agricultural inputs, with low-density polyethylene (LDPE) being the most extensively used plastic type. The carbonyl index and hydroxyl indices of the detected LDPE microplastics ranged from 0.041 to 0.96 and 0.092 to 1.20, respectively. The study highlights the significance of mulching management and agronomic practices in shaping microplastic characteristics. Potential pollution sources include agricultural inputs, irrigation equipment, domestic waste, and tire wear. Proposed effective strategies include responsible plastic use, robust waste management, and irrigation system upgrades, establishing a foundation for future ecological risk assessments and effective management approaches in the Hetao Irrigation District. ENVIRONMENTAL IMPLICATION: The harmful substances studied in this paper are microplastics, which are widely distributed in the environment and have potential ecological risks. This study is the first to investigate the characteristics of microplastics in farmland soil within the Hetao Irrigation Area, a region that is of critical importance to agricultural production in the Yellow River Basin of China. The study provides comprehensive insights into the factors influencing the characteristics of microplastics and speculates on their sources. These findings offer a novel perspective on the assessment of microplastic contamination in the area and provide valuable recommendations for prevention and control measures.

10.
Environ Sci Process Impacts ; 26(1): 8-15, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38050906

RESUMO

Plastic film mulching stands as a globally employed agricultural technology pivotal to agricultural progress. Nevertheless, the environmental degradation of plastic mulch films underscores their role as a major source of secondary plastic pollutants, particularly microplastics. While a growing body of research has drawn attention to the rising issue of microplastic pollution and its environmental implications stemming from the use of plastic mulch films, there remains a significant knowledge gap regarding the kinetics and rate-limiting mechanisms governing the generation of microplastics during processes driven by plastic photodegradation. Moreover, a comprehensive quantification of the connection between mulch deterioration and the behavior of microplastic release and accumulation has yet to be fully realized. In this study, a kinetic equation was formulated to characterize the degradation of plastic mulch films and the subsequent release and accumulation of microplastics under light exposure. The results demonstrate that with increasing irradiation time, the change in the release rate exhibits a bell-shaped Gaussian probability distribution, while the cumulative alteration of microplastics follows a Gaussian distribution. Remarkably, once the exposure time reaches µ + 3σ, the accumulation plateaus at 99.7%. This research establishes a theoretical framework for the prospective assessment of plastic mulch lifespan and its environmental repercussions. Moreover, the findings provide valuable insights for optimizing plastic mulch design and devising strategies to mitigate microplastic pollution.


Assuntos
Microplásticos , Plásticos , Solo , Estudos Prospectivos , Agricultura
11.
Small ; 20(14): e2308788, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37988647

RESUMO

Heteroatom-doped porous carbon materials have investigated to promote the energy density of zinc-ion hybrid capacitors (ZICs). Yet, the quest for high-performance carbon materials or cathodes brings to light the question of which dopants facilitate fast energy storage kinetics and various types of pseudocapacitive reactions. Investigation of carbon materials with precise quantitative dopants as the key variable represents an effective appropriate approach to comprehending the intricate role of dopants in energy storage areas. Here, a straightforward solvothermal strategy is demonstrated for a variety of pristine and iron-incorporated polymer microspheres, used as precursors for durable spherical carbons intended for cathode applications in ZICs. The strategy effectively governs the incorporation of dopants within the carbon materials, whilewhile maintaining consistent morphology, microtexture, and pore structure across different carbon variations. The synergistic effect of various dopants enhance the pseudocapacitance and facilitate the ion storage process. In consequence, the optimal cathode delivers considerable capacity (178.8 mAh g-1 at 0.5 A g-1), good energy density (120.2 Wh kg-1 at 336 W kg-1), and excellent cycling stability (101.5% capacity retention at 35 000 cycles). The demonstration showcases a viable method for crafting carbon materials with precise dopants to accommodate the zinc anode, thus enabling high-capacity and high-energy ZICs.

12.
J Hazard Mater ; 465: 133302, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38141305

RESUMO

Light stabilizers are commonly used as additives in mulching films and have environmental persistence, bioaccumulation and ecotoxicity. However, their occurrence and distribution in mulching films and accumulation in mulched soils are seldom reported. This study firstly presents a comprehensive screening of 19 light stabilizers in 65 mulching films and 30 farmland soils collected in China, of which five and eight light stabilizers were 100% detected, respectively. The light stabilizer concentration in biodegradable mulching films was significantly higher than that in polyethylene ones, with median concentrations of 1.75 × 106 µg/kg and 4.86 × 103 µg/kg, respectively. Furthermore, a positive correlation was observed between the light stabilizer concentration in mulching films and in soils. This indicates that mulching films play a critical role in the accumulation of light stabilizers in farmland soils, and biodegradable mulching films significantly increase benzotriazole light stabilizers in soils. Although the light stabilizer concentration in farmland soil is relatively low, the sustainable quantities of mulching film input and the long-term accumulation will still pose a threat to the ecological environment and organism health. Consequently, our work reveals the occurrence and environmental risk of light stabilizers in mulching films and farmland soils and brings attention to light stabilizers in the soil environment.


Assuntos
Agricultura , Solo , Polietileno , Meio Ambiente , Fazendas , China , Plásticos
13.
Chemosphere ; 344: 140383, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37832891

RESUMO

Polyethylene (PE) mulch films have been widely used in agriculture and led to a significant pollution in cultivated soils. It is desirable to develop the sustainable method for the degradation of PE. As an environment friendly approach, microbial or enzymatic degradation of PE could meet this demanding. Thus, more microbial strains are required for illustrating biodegrading pathway and developing efficient biological method. In this study, Gordonia polyisoprenivorans B251 capable of degrading PE was isolated from bacterial enrichment with hexadecane as a sole carbon source for two years, in which genus Gordonia had dominated. As revealed by microbial growth curve, the strain B251 had the highest growth rate than other tested strains in the mediums either with hexadecane or PE particles as sole carbon source. The formation of biofilms in both enriched culture and G. polyisoprenivorans B251 pure culture attached to PE film was observed. The capability for PE degradation of individual strain was screened by 30-day incubation with PE film and confirmed by the presence of hydroxyl, carbonyl, carbon-carbon double bond and ether groups in FT-IR analysis and cracks on the surface of PE film observed by scanning electron microscopy (SEM). Therefore, Gordonia polyisoprenivorans, reported as their degradation of environmental contaminants in previous study, were also identified in current study as a candidate for polyethylene biodegradation.


Assuntos
Bactérias , Polietileno , Polietileno/química , Espectroscopia de Infravermelho com Transformada de Fourier , Biodegradação Ambiental , Biofilmes , Carbono
14.
Sci Total Environ ; 905: 166935, 2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-37690755

RESUMO

There is a major knowledge gap concerning the extent of microplastic pollution in agronomic regions of China, which represent a plastic use hotspot. In order to clarify the amendment of agronomic region and plastic film mulching mode to microplastics distribution, the characteristics of microplastics distributed in agricultural soils from three typical regions (Beijing (BJ), Shandong (SD), and Xinjiang (XJ)) with two plastic film mulching modes (greenhouse (G) and conventional field-based film mulching (M)) in China were investigated. Microplastics weight and their response to planting regions were also evaluated in this study. The result showed that the average abundance of microplastics in soils from BJ, SD, and XJ was 1.83 × 104 items kg-1, 4.02 × 104 items kg-1, and 3.39 × 104 items kg-1, and the estimated weight of microplastics per kg of dry soils was 3.12 mg kg-1, 5.63 mg kg-1, and 7.99 mg kg-1, respectively. Microplastics in farmland were mainly of small particle size (50 to 250 µm), with their abundance decreasing with increasing particle size. Among the microplastics detected, polyethylene and polypropylene were the two dominant types present, accounting for 50.0% and 19.7%, respectively. The standard total effect of planting regions on microplastic number and weight was 31.8% and 32.3%, and plastic film mulching modes (G vs. M) could explain 34.4% of the total variation of microplastic compositions with a contribution rate of 65.6% in this study. This research provides key data for an assessment of the environmental risk of microplastics and supports the development of guidelines for the sustainable use of agricultural plastic film. Further, it is necessary to quantify and assess the contribution of other different plastic sources to microplastics in soil. Big data technologies or isotope tracer techniques may be promising approaches.

15.
J Colloid Interface Sci ; 650(Pt A): 193-202, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37402325

RESUMO

Solar-driven electrochemical NO3- reduction reaction (NO3-RR) is a clean and sustainable strategy that can convert pollutant NO3- in wastewater to value-added NH3. In recent years, cobalt oxides-based catalysts have shown their intrinsic catalytic properties toward NO3-RR but still have room for improvement through catalyst design. Coupling metal oxides with noble metal has been demonstrated to improve electrochemical catalytic efficiency. Here, we use Au species to tune the surface structure of Co3O4 and improve the efficiency of NO3-RR to NH3. The obtained Au nanocrystals-Co3O4 catalyst exhibited an onset potential of 0.54 V vs RHE, NH3 yield rate of 27.86 µg/h·cm2, and Faradaic efficiency (FE) of 83.1% at 0.437 V vs RHE in an H-cell, which is much higher than Au small species (Au clusters or single atoms)-Co3O4 (15.12 µg/h·cm2) and pure Co3O4 (11.38 µg/h·cm2), respectively. Combined experiments with theory calculations, we attributed the enhanced performance of Au nanocrystals-Co3O4 to the reduced energy barrier of *NO hydrogenation to the *NHO and suppression of HER, which originated from the charge transfer from Au to Co3O4. Using an amorphous silicon triple-junction (a-Si TJ) as the solar cell and an anion exchange membrane electrolyzer (AME), an unassisted solar-driven NO3-RR to NH3 prototype was realized with a yield rate of 4.65 mg/h and FE of 92.1%.

16.
J Hazard Mater ; 459: 132068, 2023 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-37494798

RESUMO

Microplastics are widely distributed in the environment and pose potential ecological risks, increasing to be one of the most important environmental pollutants. However, when assessing the characteristics of microplastic contamination in environmental samples, inadequate quality control measures for the working solutions may introduce additional microplastic contamination and lead to an overestimation of microplastic abundance in the samples. In this study, we evaluated the microplastic contamination characteristics in commonly used flotation and digestion reagents to assess errors caused by microplastics in the reagents. The results showed that the abundance of microplastics in the reagents ranged from 0.8 to 43.4 items/g, with the abundance of microplastics in flotation reagents being lower than that in digestion reagents. The shapes of the detected microplastics included particles, fibers, and fragments, and their size and outline were generally small, with most being below 100 µm. The most common types of polymers detected were polyethylene and polypropylene. In order to improve the universality and readability of the results, the detected microplastic abundances were converted into the actual application concentration of the working fluid. It was found that the potential contamination of microplastics in untreated flotation solutions ranged from 1.5 to 30.8 items/mL, while in digestion solutions ranged from 0.1 to 2.3 items/mL. Our study emphasizes the need for quality control measures, such as suction filtration, when evaluating microplastics in environmental samples or conducting chemical and biological tests related to microplastics.

17.
J Environ Manage ; 344: 118433, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37336015

RESUMO

Worldwide physiological research has aimed to decelerate the aging of crop leaves by optimizing fertilization measures to improve crop or biomass yield. Solid organic fertilizers can be combined with chemical fertilizers to delay the aging of crop leaves. Biogas slurry is a liquid organic fertilizer produced by the anaerobic fermentation of livestock and poultry manure and other resources, and it can partially replace chemical fertilizers in field application via drip irrigation systems. However, the impact of biogas slurry topdressing on leaf aging remains unclear. This study investigated treatments with no topdressing (control, CK) and five topdressing patterns of biogas slurry replacing chemical fertilizer (nitrogen) at 100%, 75%, 50%, 25%, and 0% (100%BS, 75%BS, 50%BS, 25%BS, CF). The effects of different proportions of biogas slurry on leaf senescence rate, photosynthetic pigments, osmotic adjustment substances, antioxidant defense enzymes, and nitrogen metabolism related enzyme activities of maize were analyzed. Subsequently, the mechanisms of biogas slurry topdressing on the leaf senescence rate of maize were explored. The results showed that the mean decreasing rate of relative green leaf area (Vm) treated with biogas slurry decreased by 3.7%-17.1% and the duration of leaf area duration (LAD) increased by 3.7%-17.1% compared with the results for CK. The maximum senescence rate of 100%BS was delayed by 4.4 and 5.6 d compared to the results for CF and CK, respectively. During the senescence of maize leaves, the use of biogas slurry topdressing increased the content of chlorophyll, decreased the water loss and the accumulation rate of malondialdehyde and proline in leaves, and increased the activities of catalase, peroxidase, and superoxide dismutase in the later growth and development periods of maize. In addition, biogas slurry topdressing improved the nitrogen transport efficiency of the leaves and ensured continuous and efficient ammonium assimilation. Furthermore, there was a strong correlation between leaf senescence and the investigated physiological indices. Cluster analysis showed that the 100%BS treatment exhibited the most prominent effect on leaf senescence. Biogas slurry topdressing as a substitute for chemical fertilizer can be potentially used as an anti-aging regulation measure for crops to decrease the damage induced by senescence.


Assuntos
Biocombustíveis , Fertilizantes , Zea mays , Senescência Vegetal , Nitrogênio/farmacologia , Solo/química
18.
Nat Commun ; 14(1): 3824, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37380642

RESUMO

The discovery of magnetic order in atomically-thin van der Waals materials has strengthened the alliance between spintronics and two-dimensional materials. An important use of magnetic two-dimensional materials in spintronic devices, which has not yet been demonstrated, would be for coherent spin injection via the spin-pumping effect. Here, we report spin pumping from Cr2Ge2Te6 into Pt or W and detection of the spin current by inverse spin Hall effect. The magnetization dynamics of the hybrid Cr2Ge2Te6/Pt system are measured, and a magnetic damping constant of ~ 4-10 × 10-4 is obtained for thick Cr2Ge2Te6 flakes, a record low for ferromagnetic van der Waals materials. Moreover, a high interface spin transmission efficiency (a spin mixing conductance of 2.4 × 1019/m2) is directly extracted, which is instrumental in delivering spin-related quantities such as spin angular momentum and spin-orbit torque across an interface of the van der Waals system. The low magnetic damping that promotes efficient spin current generation together with high interfacial spin transmission efficiency suggests promising applications for integrating Cr2Ge2Te6 into low-temperature two-dimensional spintronic devices as the source of coherent spin or magnon current.

19.
Adv Mater ; 35(31): e2302350, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37141542

RESUMO

Giant spin-orbit torque (SOT) from topological insulators (TIs) has great potential for low-power SOT-driven magnetic random-access memory (SOT-MRAM). In this work, a functional 3-terminal SOT-MRAM device is demonstrated by integrating the TI [(BiSb)2 Te3 ] with perpendicular magnetic tunnel junctions (pMTJs), where the tunneling magnetoresistance is employed for the effective reading method. An ultralow switching current density of 1.5 × 105  A cm-2 is achieved in the TI-pMTJ device at room temperature, which is 1-2 orders of magnitude lower than that in conventional heavy-metals-based systems, due to the high SOT efficiency θSH = 1.16 of (BiSb)2 Te3 . Furthermore, all-electrical field-free writing is realized by the synergistic effect of a small spin-transfer torque current during the SOT. The thermal stability factor (Δ = 66) shows the high retention time (>10 years) of the TI-pMTJ device. This work sheds light to the future low-power, high-density, and high-endurance/retention magnetic memory technology based on quantum materials.

20.
Sci Total Environ ; 880: 162984, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-36963692

RESUMO

Soil mulching technologies are effective practices which alleviate non-point source pollution and carbon emissions, while ensuring grain production security and increasing water productivity. However, the lack of comprehensive understanding of the impacts of mulching technologies on rice fields has hindered progress in global implementation due to the varying environments and application conditions under which they are implemented. This study conducted a meta-analysis based on 2412 groups of field experiment data from 313 studies to evaluate the effects of soil mulching methods on rice production, greenhouse gas (GHG) emissions and water use efficiency. The results show that plastic mulching, straw mulching and no mulching (PM, SM and NM) have reduced CH4 emissions (68.8 %, 61.4 % and 57.2 %), increased N2O emissions (84.8 %, 89.1 % and 96.6 %), reduced global warming potentials (50.7 %, 47.5 % and 46.8 %) and improved water use efficiency (50.2 %, 40.9 % and 34.0 %) compared with continuous flooding irrigation. However, PM increased rice yield (1.6 %), while SM and NM decreased yield (4.3 % and 9.2 %). Furthermore, analysis using random forest models revealed that rice yield, GHG emissions and WUE response to soil mulching were related to climate, soil properties, fertilizer and rice varieties. Our findings can guide the implementation of plastic mulching technology in priority areas, contribute to agricultural carbon neutrality and support the development of practical guidelines for farmers.


Assuntos
Gases de Efeito Estufa , Oryza , Gases de Efeito Estufa/análise , Plásticos , Óxido Nitroso/análise , Agricultura/métodos , Solo , Fertilizantes/análise , Carbono , Água , Metano/análise , China
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA