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A novel decomposition method that adheres to both local time translation symmetry and spatial rotational symmetry is proposed in this study, thereby extending the limitations of existing methods, which are typically restricted to quasi-two-dimensional configurations. Grounded in the FIK and RD identities, this method provides a clear physical and reliable interpretation suitable for arbitrary-curvature profiles. Utilizing this method, an analysis of the aerothermodynamic characteristics of the bistable states of curved compression ramp flows was conducted. The results reveal that the generation of undisturbed and peak Cf is dominated by viscous dissipation. Specifically, flow separation happens when all of the energy input from the work exerted by the adverse pressure gradient (APG) is insufficient to be entirely converted into local viscous dissipation and kinetic energy. Furthermore, the propensity for flow separation at higher wall temperatures is firstly elucidated quantitatively from the perspective of the work by the APG. The peak heat flux is predominantly triggered by the work of viscous stress, with the secondary contribution from energy transport playing a more significant role in the generation of the peak heat flux of the separation state than that of the attachment state.

Abstract A highly efficient on-chip acousto-optic modulator is as a key component and occupies an exceptional position in microwave-to-optical conversion. Homogeneous thin-film lithium niobate is preferentially employed to build the suspended configuration for the acoustic resonant cavity, with the aim of improving the modulation efficiency of the device. However, the limited cavity length and complex fabrication recipe of the suspended prototype restrain further breakthroughs in modulation efficiency and impose challenges for waveguide fabrication. In this work, based on a nonsuspended thin-film lithium niobate-chalcogenide glass hybrid Mach–Zehnder interferometer waveguide platform, we propose and demonstrate a built-in push-pull acousto-optic modulator with a half-wave-voltage-length product V π L as low as 0.03 V cm that presents a modulation efficiency comparable to that of a state-of-the-art suspended counterpart. A microwave modulation link is demonstrated using our developed built-in push-pull acousto-optic modulator, which has the advantage of low power consumption. The nontrivial acousto-optic modulation performance benefits from the superior photoelastic property of the chalcogenide membrane and the completely bidirectional participation of the antisymmetric Rayleigh surface acoustic wave mode excited by the impedance-matched interdigital transducer, overcoming the issue of low modulation efficiency induced by the incoordinate energy attenuation of acoustic waves applied to the Mach–Zehnder interferometer with two arms in traditional push-pull acousto-optic modulators.

As a typical green production technology, straw return affects environmental pollution control and waste recycling. However, in reality, farmers are not active in returning straw to the field. This study constructed a theoretical analysis of farmers’ straw-returning behavior under the conditions of labor aging, socialization service, and environmental regulation. Based on the survey data from 540 households in the Province of Sichuan, we empirically study the relationship between labor aging and farmers’ straw-returning behavior by using the binary logistic regression model and explore the moderating effects of socialization service and environmental regulation on labor aging and straw-returning behavior. The results show that: (1) Aging laborers in rural households constitute a higher proportion, accounting for 29% of the rural household labor force. However, there is limited enthusiasm among farmers to adopt straw returning to the field, with only 65% of farmers adopting this technology. (2) The labor aging hinders farmers’ straw-returning behavior. Specifically, under other fixed conditions, the behavior of straw returning decreases by 0.647 units when the labor aging increases by one unit. (3) Socialization services and economic incentives can mitigate the adverse effects of labor aging on straw-returning behavior, while mandatory constraints do not. (4) The heterogeneity analysis shows that labor aging has a stronger inhibitory effect on straw-returning behavior when the land scale of farmers is lower than the average level and the area is not plain.

It is of great significance for global environmental governance to guide farmers to effectively perceive climate change. Based on the survey data of 540 farmers in Sichuan Province, China, this study used binary Logit model and Multinomial Logistic Regression model to explore the effects of farmers’ space-time perception of climate change and their interaction effects on farmers’ adaptation behavior to climate change. The results showed that: (1) 88.51% of farmers took adaptation measures to climate change, and 61.11% of them took both passive and active adaptation measures. Among the 7 measures, the highest rate of “Increase irrigation” is 23%, and the lowest rate of “Migrant work” is only 5%. (2) The scale difference of farmers’ time perception of climate change has a significant positive impact on their adaptive behavior of climate change. In terms of time: climate change perception in the next 5 years > in the next 10 years > in the next 15 years. (3) The scale difference of farmers’ space perception of climate change has a significant positive impact on their adaptation behavior to climate change. In other words, spatially, farmers’ perception of climate change is global > national > local village (the perception of local province is not significant). (4) Farmers’ space-time perception of climate change significantly affects farmers’ adaptive behavior. Among them, “farmers’ perception of climate change in the next 5 years” and their own “village’s perception of climate change” play an important role. This study will help deepen the understanding of farmers’ perception of climate change and their adaptive behavior, and provide reference for national policy making.

The efficient crack eliminated stop-hole measure was proposed to repair and reduce the stress concentration associated fracture risk of the corrugated plate girders by setting it at the critical joint of flange plate with tightened bolts and gaskets under preloading. To investigate the fracture behaviour of these repaired girders, parametric finite element analysis was conducted, focusing on the mechanical feature and stress intensity factor of crack stop-hole in this paper. The numerical model was verified against experimental results first, and then the stress characteristics due to the presence of crack open-hole were analysed. It was found that the moderate-sized open-hole was more effective than the over-sized open-hole in the reduction of stress concentration. For the model with prestressed crack stop-hole through bolt preloading, the stress concentration was nearly 50% with the prestress around open-hole increased to 46 MPa, but such a reduction is inconspicuous for even higher prestress. Relatively high circumferential stress gradients and the crack open angle of oversized crack stop-holes were decreased owing to additional prestress effects from the gasket. Finally, the shift from the original tensile area around the edge of the crack open-hole that was prone to fatigue cracking to a compression-oriented area is beneficial for the reduction of stress intensity factor of the prestressed crack stop-holes. It was also demonstrated that the enlargement of crack open-hole has limited influence on the reduction of stress intensity factor and crack propagation. In contrast, higher bolt prestress was more beneficial in consistently reducing the stress intensity factor of the model with the crack open-hole, even containing long crack.

Bolted spherical joints, due to their prominent merits in installation, have been widely used in modern spatial structures. Despite significant research, there is a lack of understanding of their flexural fracture behaviour, which is important for the catastrophe prevention of the whole structure. Given the recent development to fill this knowledge gap, it is the objective of this paper to experimentally investigate the flexural bending capacity of the overall fracture section featured by a heightened neutral axis and fracture behaviour related to variable crack depth in screw threads. Accordingly, two full-scale bolted spherical joints with different bolt diameters were evaluated under three-point bending. The fracture behaviour of bolted spherical joints is first revealed with respect to typical stress distribution and fracture mode. A new theoretical flexural bending capacity expression for the fracture section with a heightened neutral axis is proposed and validated. A numerical model is then developed to estimate the stress amplification and stress intensity factors related to the crack opening (mode-I) fracture for the screw threads of these joints. The model is validated against the theoretical solutions of the thread-tooth-root model. The maximum stress of the screw thread is shown to take place at the same location as the test bolted sphere, while its magnitude can be greatly reduced with an increased thread root radius and flank angle. Finally, different design variants related to threads that have influences on the SIFs are compared, and the moderate steepness of the flank thread has been found to be efficient in reducing the joint fracture. The research findings could thus be beneficial for further improving the fracture resistance of bolted spherical joints.

Land certification and adjustment experience, which are of great significance to strengthen farmers’ acceptance of the green production technologies (the GPTs), are important factors that affect the stability of land property. Based on the research data of 540 farmers in Sichuan, China, the probit model is used in this research to explore the effect of the land certification upon the GPTs acceptance of farmers and discuss the moderation effect of land adjustment experience (large-scale adjustment and small-scale adjustment). The results show the following. (1) Overall, 10% of the farmers have not obtained the certificates, 17% of the farmers have experienced small-scale land adjustment, and 3% of the farmers have experienced large-scale land adjustment. Meanwhile, 15% of the farmers have not adopted any the green production technologies (the GPTs), and the rest have adopted at least one green production technology. (2) Land certification affects farmers’ acceptance of the GPTs in a significant way. (3) Small-scale land adjustment will weaken the role of land certification in promoting farmers’ acceptance of the green production technologies (the GPTs), while large-scale land adjustment will not. (4) For farmers with large scale of land, low extent of land fragmentation, and high extent of dependence on agricultural income, land certification will positively promote farmers’ decision making on whether to accept the GPTs.

Crustal movement and land subsidence will cause tower foundation settlement, which seriously affects the safety of transmission line operation. This paper proposed a short-term failure warning method for transmission tower under land subsidence condition based on finite element method, strain monitoring and time series prediction. By simulating the stress distribution of the tower in actual foundation settlement, the weak components of the settlement tower were founded. Combined with the finite element simulation results in various conditions, the reliability of simulation results is verified, and the strain variation range of the corresponding measuring point is obtained. By installing the real-time strain monitoring system and establishing the autoregressive integrated moving average (ARIMA) time series forecast model, warning of the failure of the tower can be sounded in short time according to the strain monitoring and forecasting results. The field results show that the tower is in good condition and with no risk in short term. The method proposed by this paper is economical and easy to operate, which can be used to conduct the emergency treatment of the dangerous tower under land subsidence condition.

Carbon emission reduction in agriculture is an important link to achieving green agricultural development and a rural ecological environment, and Low-Carbon Agricultural Technology (LCAT) of farmers is an important means to achieve carbon emission reduction in agriculture. Based on data obtained from a survey of 540 farmers in Sichuan province in 2021, the Tobit model was used to empirically analyze the effect of trust on farmers’ LCAT adoption. The results show that (1) the trust level of farmers is high and the order is special trust > institutional trust > general trust. At the same time, the intensity of adoption of LCAT by farmers is not high, and the average number of LCAT adopted by each family is 1.13. Among them, straw-returning technology was adopted to a high degree, with 54.63% of farmers using it. (2) Farmers’ trust significantly enhances farmers’ LCAT adoption behavior, and the magnitude of the effect is characterized by specific trust > general trust > institutional trust chain. (3) Heterogeneity analysis shows that the influence of farmers’ specific trust and institutional trust in plain areas on the intensity of LCAT adoption is stronger than that of farmers in non-plain areas, and the influence of general trust of farmers in non-plain areas on the intensity of LCAT adoption is stronger than that of farmers in plain areas. The impact of specific trust, general trust, and institutional trust on LCAT adoption was stronger for the new generation of farmers than for the older generation of farmers. (4) Herding effect plays a mediating role in special trust, institutional trust, and LCAT adoption. This study can deepen our understanding of the relationship between farmers’ trust and LCAT adoption behavior, and then provide theoretical reference and practical basis for the promotion of LCAT and the improvement of farmers’ LCAT adoption level from the perspective of trust.

With the continuous emphasis of the country on the construction of ecological civilization, promoting the utilization of straw resources has become an important measure to achieve green agricultural development. Based on the survey data of 540 households in Sichuan Province and under the guidance of the theory of planned behavior, this paper constructed the IV-Probit model to explore the impact of land transfer on the straw resource utilization of households. The results show that: (1) land transfer in and land transfer out can significantly promote the utilization of straw resources by farmers. (2) Heterogeneity analysis showed that land transfer in had a positive effect on crop straw utilization of the new generation and large-scale farmers. (3) Land transfer in can promote the utilization of straw resources by improving farmers’ economic cognition and efficacy cognition; land transfer out can promote the utilization of straw resources by improving farmers’ efficacy cognition. Accordingly, the government should improve the land transfer market, increase technology propaganda, and create an excellent policy environment to promote farmers’ participation in straw resource utilization.

Chronic diarrhea is associated with enteric dysbiosis and provokes the overuse of antibiotics. Fecal microbiota transplantation (FMT) is a promising therapy, but it shows discrepant clinical efficacy. Bacterial colonization in recipients has been studied, although little is known about the role of gut fungi and Archaea after FMT. In this study, we evaluated the efficacy of human-derived FMT on spontaneous chronic diarrhea cynomolgus monkeys and revealed the effector mechanisms. We demonstrated that FMT can mitigate the appearance of diarrheal symptoms and inhibit the increase in interleukin-6, interleukin-8, interleukin-1β, and interferon-γ and the decrease in interleukin-10 in serum. We confirmed that FMT restored the disturbance of gut bacteria by reducing the relative abundances of potential pathogens, including Cloacibacillus porcorum, Desulfovibrio desulfuricans, Erysipelotrichaceae bacterium 5_2_54FAA, and Erysipelotrichaceae bacterium 21_3, and increasing the levels of Lactobacillus fermentum and Lactobacillus ruminis CAG_367 in diarrheal monkeys. The metabolic pathways of healthy and FMT monkeys’ gut bacteria were enriched in amino acid metabolism, carbohydrate metabolism, and lipid metabolism, while the metabolic pathways of pre-FMT monkeys’ gut bacteria were enriched in antibiotic production. Moreover, a higher Ascomycota/Basidiomycota ratio, higher Aspergillus levels, and lower Trichosporon asahii abundance were present in intestinal fungi after FMT. Although the abundance of the Archaea Methanosphaera stastmanae did not change significantly, it was inversely correlated with the anti-inflammatory factor IL-4 after FMT. These results support the further development and application of FMT for chronic diarrhea.

Chemosensors based on traditional fluorescent dyes have always contributed to the development of chemical sensor areas. In this review, the rhodamine-based chemosensors’ improvements and applications from 2018 to 2022 are discussed, mainly focusing on cations (metal ions and H+), anions (CN−, F−, etc.), and small bio-functional molecules’ (thiols, amino acids, etc.) detection. Specifically, this review highlights the detection target, detection limit, detection solution system, detection mechanism, and performance of the rhodamine-based sensors. Although these rhodamine-based sensors are well developed, their repeatability and sensitivity still need significant improvement. This review is expected to bring new clues and bright ideas to researchers for further advances in rhodamine-based chemosensors in the future.

(Motivation) With the transfer of labor force and the continuous improvement of household income, the household energy consumption structure is also changing. (Gaps) However, few studies have explored the correlations between labor off-farm employment (LOE) and farmers’ cooking clean energy (CCE) consumption. (Methodologies) Using survey data of 8198 farmers in 27 provinces from China’s labor dynamic survey in 2016, the IV-Probit model was used to analyze the impact of LOE on CCE use, and the mediation effect model was used to examine the specific mechanism of action between them. (Results) The results found that: (1) LOE accounted for about 39%, and farmers’ utilization rate of CCE accounted for 40%. (2) LOE has significantly promoted the use of CCE by farmers, and this action mechanism is mainly realized through three paths, that is, per capita annual cash income, social relationship network, and family population structure. (3) The heterogeneity analysis results showed that the head of the household having a university education or above, the family being located in rural areas and mountainous areas, and LOE will have a greater positive impact on the farmers’ CCE use. (Policy) From the micro perspective of LOE, this study can deepen our understanding of LOE and CCE use decisions, and then provide a reference for the rational allocation of labor resources and farmers’ CCE-related policy formulation.

At present, with the increasingly growing application of Internet of Things, virtualization and intelligent technologies, and the maturity of smart campus systems, campus card technology based on radio frequency identification (RFID) has developed rapidly. Due to the convenience of use, it is widely used in dormitory access control system, book borrowing system, attendance system, and payment system. Because the data carried by the RFID card is more and more complex, the requirements for its security are getting higher and higher. In order to solve the problem of identity authentication and privacy protection of the RFID application existed in the digital campus in recent years, an improved mutual authentication protocol in mobile RFID for smart campus is put forward by analyzing and studying existing smart campus authentication protocols based on hash algorithm, which uses the technology of random number S and time stamp T. This protocol implements mutual authentication among the tag, reader, and backend database without the premise that the signal path between the database and reader communication is a safe signal path and can effectively resist counterfeit attack, replay attack, position tracking attack, de-synchronization attack, eavesdropping attack, denial of service attack, and man-in-the-middle attack, and it can also guarantee forward security. Due to the large data operations and storage have been transferred to readers and backend data, the protocol is formally proved to have a strong reliability and a good security. In addition, through the comparison with other existing authentication protocols on the resident variable storage overhead, the cost of computing complexity and the security performance, the authentication protocol proposed in this paper has a better storage and calculation performance, and it can better satisfy the security requirements in mobile RFID applications for smart campus in the future and has a good application prospect.

Currently, there is limited knowledge about the immunological profiles of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). We used computer-based immunoinformatic analysis and the newly resolved 3-dimensional (3D) structures of the SARS-CoV-2 S trimeric protein, together with analyses of the immunogenic profiles of SARS-CoV, to anticipate potential B-cell and T-cell epitopes of the SARS-CoV-2 S protein for vaccine design, particularly for peptide-driven vaccine design and serological diagnosis. Nine conserved linear B-cell epitopes and multiple discontinuous B-cell epitopes composed of 69 residues on the surface of the SARS-CoV-2 trimeric S protein were predicted to be highly antigenic. We found that the SARS-CoV-2 S protein has a different antigenic profile than that of the SARS-CoV S protein due to the variations in their primary and 3D structures. Importantly, SARS-CoV-2 may exploit an immune evasion mechanism through two point mutations in the critical and conserved linear neutralization epitope (overlap with fusion peptide) around a sparsely glycosylated area. These mutations lead to a significant decrease in the antigenicity of this epitope in the SARS-CoV-2 S protein. In addition, 62 T-cell epitopes in the SARS-CoV-2 S protein were predicted in our study. The structure-based immunoinformatic analysis for the SARS-CoV-2 S protein in this study may improve vaccine design, diagnosis, and immunotherapy against the pandemic of COVID-19.

Rural households are micro-organizational systems that are composed of different family members. Against a background of fragmented land patterns and massive labor migration in China, it is of great significance for the sustainable development of regional economies to explore the optimal selection of livelihood strategies by rural households. Using a survey containing data from 8031 rural households from 27 provinces in China, this study analyzed the characteristics and spatial distribution trends of the land management scale, family life cycle, and livelihood strategy selection of rural households, and constructed Tobit econometric models to explore the correlations among these factors. The results show: (1) Rural households’ land management scale was primarily small-scale and, as it expanded, the proportion of the total cash income coming from agricultural activities increased. A relative majority of rural households were in the middle period of the family life cycle, and relatively few rural households were in the starting and empty nest periods. The proportion of the total cash income of rural households coming from agricultural pursuits while in the stable and the empty nest periods was relatively large, reaching 40.51% and 38.92%, respectively. In most provinces sampled, rural households’ livelihood strategies were non-agriculturally based, and the land management scale was mainly less than 0.67 ha. (2) Rural households’ land management scale positively correlated with their livelihood strategy selection. When other conditions remained unchanged, with every 1 ha increase in land management scale, the proportion of agricultural cash income in total family cash income increased, on average, by 3.7%. In comparison with rural households in the empty nest period, the proportions of agricultural cash income in the total family cash income of rural households in other family life cycles were relatively small. Specifically, for rural households in the starting, rearing, burden, stable, and maintenance periods, the proportion of agricultural cash income in the total family cash income decreased, on average, by 6.8%, 6.7%, 9.2%, 3.5%, and 16.3%, respectively.

As persistent organic pollutants, dichlorodiphenyltrichloroethanes (DDTs) and their metabolites pose considerable risks to human health and the environment. Therefore, monitoring DDTs in the environment is essential. Here, we developed a green, simple, and effective magnetic solid-phase extraction (MSPE) method coupled with gas chromatography tandem triple-quadrupole mass spectrometry to determine the DDT content of environmental water samples. A magnetic ionic liquid (IL) adsorbent was developed based on a modified magnetic multiwalled carbon nanotube/zeolitic imidazolate framework-8 (MM/ZIF-8/IL), synthesized by immobilizing the IL on the surface of MM/ZIF-8. We confirmed successful synthesis of MM/ZIF-8/IL by material characterization, and our results suggested that the MM/ZIF-8/IL had a high Brunauer−Emmett−Teller surface area (159.9 m2 g−1), good thermostability (−1). Several experimental conditions affecting the MSPE efficiency were optimized. Under the best conditions, good detection linearity was achieved (0.5−500 µg L−1) with determination coefficients ranging from 0.9927 to 0.9971. The lower limits of detection (0.0016−0.0072 µg L−1) also had good precision, having an intraday relative standard deviation (RSD) ≤ 6.5% and an interday RSD ≤ 8.9%. Finally, we used the as-developed method to determine DDT levels in environmental water samples.

In the title compound, CH6N3+·C5H8NO4−, there are two independent cations and two independent anions in the asymmetric unit. In the crystal structure, cations and anions are linked by intermolecular N—H...O hydrogen bonds into a three-dimensional network.

In the crystal structure of the title compound, C10H8N2O3·H2O, molecules are linked via intermolecular O—H...O and O—H...N hydrogen bonds into a two-dimensional network.