A Strategy for Enhancing Perpendicular Magnetic Anisotropy in Yttrium Iron Garnet Films.

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.

A composite gel formed by konjac glucomannan together with Nano-CF obtained by FeCl3-citric acid hydrolysis as a potential fat substitute.

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.

Exploring g-C3N4 as a green additive for biodegradable poly(butylene adipate-co-terephthalate) film with enhanced UV shielding and mechanical properties.

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.

Enhanced Interstitial Fluid Extraction and Rapid Analysis via Vacuum Tube-Integrated Microneedle Array Device.

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.

[Overview of the Application of Machine Learning for Identification and Environmental Risk Assessment of Microplastics].

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.

Comparative evaluation of soil accumulation of light stabilizers from biodegradable mulching films versus conventional polyethylene ones.

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.

Screening of optimal cleaning methods to reduce microplastic residues on strawberry surfaces: Characterization of microplastics in strawberry wash water.

Microplastics are widespread in facility strawberry greenhouses and can be deposited on the surface of strawberries through air currents. Investigating effective cleaning methods represents a viable strategy to reduce human ingestion of MPs. Therefore, different cleaning methods were compared: ultrasonic cleaning for 30 min, deionized water rinsing once, deionized water immersion for 30 min, and fruit immersion in washing salt for 30 min. The MPs in strawberry washing water were analyzed and compared using laser direct infrared imaging to investigate their characteristics and the optimal reduction of MPs on the surface of strawberries. The quality of the cleaning results was in the following order: water immersion > washing salt immersion > water rinsing > ultrasound. Water immersion was 1.3-2 times more effective in removing microplastics than other treatments. Furthermore, 21 polymer types were detected in the samples. Most MPs were less than 50 µm in size. The main polymers in this size range were polyamide, chlorinated polyethylene, and polyethylene terephthalate, and they mainly existed as fragments, fibers, and beads. This study provides a valuable reference for reducing human intake of microplastics through fresh fruits and vegetables.

The characteristics and influencing factors of farmland soil microplastic in Hetao Irrigation District, China.

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.

Ultrastrong to nearly deep-strong magnon-magnon coupling with a high degree of freedom in synthetic antiferromagnets.

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.

Direct and Inverse Spin Splitting Effects in Altermagnetic RuO2.

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.

Spin-torque-driven antiferromagnetic resonance.

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.