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This paper considers the dynamic response of a single degree of freedom system with nonlinear stiffness and nonlinear damping that is subjected to both resonant direct excitation and resonant parametric excitation, with a general phase between the two. This generalizes and expands on previous studies of nonlinear effects on parametric amplification, notably by including the effects of nonlinear damping, which is commonly observed in a large variety of systems, including micro- and nano-scale resonators. Using the method of averaging, a thorough parameter study is carried out that describes the effects of the amplitudes and relative phase of the two forms of excitation. The effects of nonlinear damping on the parametric gain are first derived. The transitions among various topological forms of the frequency response curves, which can include isolae, dual peaks, and loops, are determined, and bifurcation analyses in parameter spaces of interest are carried out. In general, these results provide a complete picture of the system response and allow one to select drive conditions of interest that avoid bistability while providing maximum amplitude gain, maximum phase sensitivity, or a flat resonant peak, in systems with nonlinear damping.

Water pollution is considered a serious threat to human life. An advanced oxidation process in the presence of semiconductor photocatalysts is a popular method for the effective decomposition of organic pollutants from wastewater. TiO2 nanoparticles are widely used as photocatalysts due to their low cost, chemical stability, environmental compatibility and significant efficiency. The aim of this study is to review the photocatalytic processes and their mechanism, reaction kinetics, optical and electrical properties of semiconductors and unique characteristics of titanium as the most widely used photocatalyst; and to compare the photocatalytic activity between different titania phases (anatase, rutile, and brookite) and between colorful and white TiO2 nanoparticles. Photocatalytic processes are based on the creation of electron–hole pairs. Therefore, increasing stability and separation of charge carriers could improve the photocatalytic activity. The synthesis method has a significant effect on the intensity of photocatalytic activity. The increase in the density of surface hydroxyls as well as the significant mobility of the electron–hole pairs in the anatase phase increases its photocatalytic activity compared to other phases. Electronic and structural changes lead to the synthesis of colored titania with different photocatalytic properties. Among colored titania materials, black TiO2 showed promising photocatalytic activity due to the formation of surface defects including oxygen vacancies, increasing the interaction with the light irradiation and the lifetime of photogenerated electron–hole pairs. Among non-metal elements, nitrogen doping could be effectively used to drive visible light-activated TiO2.

Recent progress in Rydberg atoms has enabled a wide range of applications in quantum sensing and quantum computation. In these applications, ultra-stable optical reference systems are essential to meet the requirements of a narrow linewidth and low technical noise. However, most existing systems are confined to laboratory settings and are not suitable for measurement-site-independent applications, such as external electric field sensors. This paper presents a transportable ultra-stable optical reference system for Rydberg excitation. The system is based on a 10 cm long ultra-low-expansion glass optical cavity, and it achieves finesse values of 410 k (at 1018 nm) and 200 k (at 852 nm). After being assembled in the experimental environment, it can still operate with only minor adjustments even after being transported over 400 km. Thanks to its vibration-insensitive design, two-stage temperature control, and hybrid locking unit, the system can maintain its locking status for up to 2 h.

Agricultural soil is related to food security and human health, antibiotics and heavy metals (HMs), as two typical pollutants, possess a high coexistence rate in the environmental medium, which is extremely prone to inducing antibiotic-HMs combined pollution. Recently, frequent human activities have led to more prominent antibiotics-HMs combined contamination in agricultural soils, especially the production and spread of antibiotic resistance genes (ARGs), heavy metal resistance genes (MRGs), antibiotic resistant bacteria (ARB), and antibiotics-HMs complexes (AMCs), which seriously threaten soil ecology and human health. This review describes the main sources (Intrinsic and manmade sources), composite mechanisms (co-selective resistance, oxidative stress, and Joint toxicity mechanism), environmental fate and the potential risks (soil ecological and human health risks) of antibiotics and HMs in agricultural soils. Finally, the current effective source blocking, transmission control, and attenuation strategies are classified for discussion, such as the application of additives and barrier materials, as well as plant and animal remediation and bioremediation, etc., pointing out that future research should focus on the whole chain process of “source-process-terminal”, intending to provide a theoretical basis and decision-making reference for future research. [Display omitted] •Intrinsic and manmade sources are elaborated for antibiotics and HMs in soil.•The main composite mechanisms between antibiotics and HMs are explained in detail.•Potential fate and risk involved in combined pollution are classified for discussion.•Blocking control and attenuation strategies for combined pollution are sorted out.•Challenges and prospects of antibiotic-HMs combined pollution in soil are directed.

Silicon photonics has emerged as one of the most prominent technological platforms for photonic integration. Compared with silicon, silicon nitride has a much broader wavelength transparency range, lower propagation loss, and less sensitivity to temperature changes, making it suitable for the manufacture of passive devices. However, silicon nitride films deposited directly on the wafer by low-pressure chemical vapor deposition exhibit large tensile stress, which may cause cracks. In the work presented herein, a process was developed to fabricate crack-free 400-nm-thick silicon nitride films based on the 200-mm complementary metal–oxide–semiconductor platform. The silicon nitride films were deposited in two steps, each followed by annealing. During the annealing, Si–H and N–H bonds in the film were broken and Si–N bonds were formed, thus improving the uniformity of the film and releasing the stress. Fourier-transform infrared measurements indicated that the films were in near-stoichiometric condition. Wafer-level testing showed that the propagation loss of an 800-nm-wide strip waveguide was 0.5 dB/cm to 0.7 dB/cm for the C-band. The insertion loss of waveguide crossing was approximately 0.15 dB, and the crosstalk was below –43 dB. The insertion loss of 1 × 2 multimode interference was less than 0.3 dB, and the nonuniformity was smaller than 10%.

Changes in the environment and in land use interconnect and interact. To ascertain the impact of meteorological factors, namely temperature, precipitation, and sunshine, on land use changes, an analysis was conducted using meteorological data and the China land use dataset spanning from 1990 to 2020. Pearson correlation analysis, grey correlation degree, and vector regression model were employed to assess the influence of meteorological factors on land use alterations and to pinpoint the primary driving forces. The findings reveal the following: (1) The spatial distribution of isohyets and isotherms is shifting towards the north, with the most significant northward movement observed in the 1600 mm isohyets and 15 °C isotherm contours. (2) Overall, the areas of croplands, shrubs, grasslands, and wetlands are decreasing, notably, with a reduction of approximately 100,000 km2 in cropland, while forests, water, and impervious surfaces are expanding annually. (3) Temperature and precipitation exhibit notable impacts on various land use types, with temperature exerting the most substantial influence on changes in cropland area, contributing to 8% of the observed variations. This study can provide a scientific basis for the rational optimization and allocation of land resources under changing environmental conditions.

Ensuring the synergistic advancement of agricultural pollution reduction and carbon emission mitigation, along with sustainable development, is crucial for achieving the ‘dual carbon’ target and modernizing agriculture. To ensure sustainable agricultural development, this study employs a coupling coordination model to explore the synergistic effects of pollution reduction and carbon emission mitigation in Henan Province, considering the agricultural carbon emissions (ACEs), agricultural non-point source pollution (ANP), and the gross value of agricultural output (GVAO) of 18 cities in Henan from 2010 to 2022 as endogenous variables. A panel vector autoregression (PVAR) model is utilized to analyze the interactive responses between agricultural pollution reduction and carbon emission mitigation and agricultural economic development. The results indicate that the degree of synergy between ACE and ANP in Henan Province has shown a trend towards higher values and a diminishing polarization phenomenon between 2010 and 2022, with most regions having degrees of synergy at higher levels. Furthermore, the interactive response relationships between agricultural pollution reduction and carbon emission mitigation and agricultural economic development reveals that the GVAO in Henan Province has a significant positive impact on both ACE and ANP, and that agricultural pollution reduction and carbon emission mitigation are constrained by agricultural economic development, with no significant bidirectional causal relationship observed overall and a lack of positive interaction in the long term. Finally, ACE, ANP, and GVAO in Henan Province exhibit a strong self-reinforcing mechanism, particularly ACE and GVAO, which show a pronounced self-growth trend. Overall, Henan Province should fully utilize the synergistic effects of agricultural pollution reduction and carbon emission mitigation to achieve coordinated progress in agricultural pollution reduction and carbon emission mitigation, as well as green and sustainable development of the agricultural economy.

TE lncRNAs are associated with m6A modification across tissues We first retrieved the TE lncRNAs from 38 normal tissues from LncSpA in 4 data resources (Fig. 1a), including Human Body Map (HBM2.0), Human Protein Atlas (HPA), the Genotype-Tissue Expression (GTEx), and the Function Annotation Of The Mammalian Genome (FANTOM) project. The extent to which variation in m6A modification of TE lncRNAs may be attributed to the expression of m6A regulators remains unknown. [...]we next sought to analyze the correlation between the expressions of m6A-modified TE lncRNAs and regulators. Table S4). [...]we identified 28 m6A-modified TE lncRNAs that had significantly higher expression in cancer patients than in healthy controls and 8 m6A-modified TE lncRNAs that had significantly lower expression (Fig. 2a and Additional file 5: Several studies have also shown that m6Am can regulate the expression of noncoding RNAs. [...]it would also be interesting to integrate such m6A and m6Am data to identify potential lncRNA biomarkers in cancer.

The growing interest in integrated sensing and communication (ISAC) has accelerated the development of unmanned aerial vehicles (UAVs) and drones for secure data transmission. In this study, the optimization of UAV trajectory and bandwidth allocation within the ISAC framework is investigated, with a focus on covert communication under energy constraints. We propose a novel deep reinforcement learning (DRL) algorithm, Soft Actor-Critic for Covert Communication and Charging (SAC-CC), to address this problem. The SAC-CC algorithm maximizes the CCTR by dynamically allocating bandwidth for sensing and communication tasks while adjusting the UAV’s trajectory to manage energy consumption. This approach ensures accurate tracking of the adversarial UAV to maintain effective covert communication. Experimental results show that SAC-CC significantly outperforms existing DRL algorithms in CCTR and improves UAV endurance. Also, its robustness under different adversarial trajectories, covert communication requirements, and charging conditions is validated. Furthermore, the UAV’s flight altitude, along with the number and distribution pattern of adversarial UAVs, directly affect covert communication performance. Finally, the study emphasizes the trade-offs among bandwidth allocation, sensing accuracy, and the balance between power spectral density and UAV energy capacity, providing key insights for the practical configuration of bandwidth and energy parameters in UAV-assisted ISAC systems.

The external cavity frequency doubling technique serves as a potent method for generating short-wavelength lasers, yet achieving high-power outputs remains challenging due to the thermal lens effect. This study systematically investigates the generation mechanism of the thermal lens effect and its impact on laser performance. By optimizing the bow-tie cavity design and leveraging a large beam waist of 106 µm to suppress thermal-induced distortions, we demonstrate a tunable 420 nm laser with up to 800 mW of output power and a peak conversion efficiency of 77%. The fundamental light source, a Ti:Sa laser locked to an ultra-stable cavity, ensures a narrow linewidth, flexible tunability, and long-term frequency stability. This high-performance blue laser enables the efficient Rydberg excitation of rubidium atoms, presenting critical applications in quantum computing, quantum simulation, and quantum precision measurement.