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Food security is an important guarantee for people's lives and national security, and digital transformation provides a new approach to improving the level of food security. Based on panel data from 30 provinces in China from 2007 to 2021, this paper empirically analyzes the impact of digital transformation on food security using fixed effects model, mediation model, moderation model, and spatial Durbin model. The research results show that: (1) digital transformation has a promoting effect on the level of food security, and there is regional heterogeneity in this promoting effect; (2) digital transformation has a mediating effect on the level of food security, which can improve the level of food security by promoting technological innovation, agricultural scale management, and marketization levels; (3) environmental regulations play a positive moderating role in the process of digital transformation promoting the level of food security; (4) there is a spatial spillover effect of digital transformation on the level of food security, which has a positive spillover effect on surrounding areas. Therefore, moving forward, it is imperative that we prioritize the digital transformation of the entire food industry chain, promote the coordinated development of digital industries in various regions, further improve the R&D innovation capability of digital technology, promote the integration of farmland to achieve large‐scale agricultural operation, and enhance the level of marketization, and at the same time improve environmental monitoring standards, fully tap the promoting effect of digital transformation on regional food security level. [EconLit Citations: Q16, Q18, R15]. [ABSTRACT FROM AUTHOR]

High‐efficiency spatial light phase modulation with wide operating bandwidth is highly significant yet challenging. Dynamic metasurfaces leveraging active materials with tunable optical response provide a promising solution. Current work is generally confronted with restricted operation bandwidth and diminished modulation efficiency, constrained by the limited tunable range and inherent absorption of active materials particular at optical frequency. Recently, the emergence of lossless phase‐change material Sb2Se3 has garnered widespread attention. Its unique characteristics, including near‐zero absorption at near‐infrared and a substantial refractive index contrast ≈0.93 during phase transition, enable the possibility of high‐performance spatial light modulation. Pioneering studies have validated the capability of lossless phase‐change metasurfaces for wavefront control, but are typically restricted to limited efficiency. Here, a hybrid phase‐change metasurface utilizing over‐coupled resonances supported by Sb2Se3 nanoholes is proposed. For the first time in optical frequency, high‐efficiency 4‐level phase modulation covering over π range is experimentally demonstrated with a sizable operating bandwidth of 42 nm and a minimum reflectance of exceeding 0.5. Leveraging optically driven localized phase‐transition technique, dynamic beam deflection is further demonstrated. The work validates the tremendous potential of phase‐change metasurfaces in achieving advanced spatial light control, signifying significant progress for the development and application of phase‐change photonic devices. [ABSTRACT FROM AUTHOR]

A high‐order improved model free adaptive control method based on iterative learning is designed to address the problem that primary permanent magnet linear motor has poor control performance, susceptibilities to load disturbances and other nonlinear disturbances during operation. The proposed algorithm adopts an improved dynamic linearization model and high‐order pseudo partial derivative estimation algorithm, which improves the data utilization of the data‐driven control algorithm, makes the algorithm better to describe the dynamic behaviour of the primary permanent magnet linear motor direct thrust force control system and improves the speed tracking accuracy and anti‐interference ability of the system. In addition, iterative learning control was adopted as feedforward compensation to further improve the control performance of the system and the stability of the closed‐loop system was analysed analytically. The simulation results show that the proposed control algorithm can improve the control accuracy of the system and suppress load disturbances and other nonlinear disturbances. [ABSTRACT FROM AUTHOR]

The macroscopic fundamental diagram (MFD) is a nonuniversal changing process over network traffic status which indicates different shapes in different networks. Hysteresis is observed in the MFD of some urban networks. It is a unique phenomenon when the network remains at low stability level and usually appears around the congestion period. This paper analyzed network peak stability through focusing on hysteresis. The formation mechanism of hysteresis is deduced from the mathematical method based on previous research studies. The precondition of hysteresis and the changing process of network state can be figured by mathematical deduction. It indicates that hysteresis only occurs conditionally in the period of macroscopic congestion and is not a universal phenomenon. Heterogeneity is an important factor leading to network instability. The hysteresis patterns of different peaks in MFD are different due to the variation of network flow. Real data are collected from Atlanta's urban network to verify the analysis of hysteresis. To discuss the changing process of hysteresis in different peaks, a three-stage division is proposed and time series is presented as a third dimension in MFD. It is worth noticing that the existence and form of hysteresis in morning and evening peaks are different. Although there is a higher peak flow in the morning peak, the stability of the evening peak performs better when hysteresis occurs in the network. The different fluctuations in the morning and evening peaks are exhibited through the 3D version of MFD. The otherness of hysteresis in different peaks is explained through a 3D coordinate system with cross-compared corresponding indexes. [ABSTRACT FROM AUTHOR]

Infrared light driven photocatalytic reduction of atmospheric CO2 is challenging due to the ultralow concentration of CO2 (0.04 %) and the low energy of infrared light. Herein, we develop a metallic nickel‐based metal–organic framework loaded with Pt (Pt/Ni‐MOF), which shows excellent activity for thermal‐photocatalytic conversion of atmospheric CO2 with H2 even under infrared light irradiation. The open Ni sites are beneficial to capture and activate atmospheric CO2, while the photogenerated electrons dominate H2 dissociation on the Pt sites. Simultaneously, thermal energy results in spilling of the dissociated H2 to Ni sites, where the adsorbed CO2 is thermally reduced to CO and CH4. The synergistic interplay of dual‐active‐sites renders Pt/Ni‐MOF a record efficiency of 9.57 % at 940 nm for converting atmospheric CO2, enables the procurement of CO2 to be independent of the emission sources, and improves the energy efficiency for trace CO2 conversion by eliminating the capture media regeneration and molecular CO2 release. [ABSTRACT FROM AUTHOR]

Dynamic metasurfaces provide exciting opportunities for spatial light modulation with ultra‐compact footprint and high resolution. Designs reported so far typically suffer from efficiency problem due to the strong coupling between amplitude and phase modulation. Huygens metasurface design eliminates the back propagation with interference of dual resonances, offering a potential solution for phase‐only modulation. However, the intrinsic dispersion mismatch between the dual modes restricts this design to a highly limited bandwidth. Here, a dynamic phase‐change metasurface design that enables transmissive phase modulation covering over 240° with high‐level transmisstance maintained over 0.8 and a large operation bandwidth of 80 nm ranging from 1516 to 1596 nm, is presented. To verify the potential usage of this design, a multi‐state phase‐change control scheme that enables quasi‐continuous phase modulation is further provided. The key feature of this design is the leverage of congener Huygens concept. Judicious incorporation of lossless phase‐change material (PCM) with congener Huygens metasurface allows wideband holding of Huygens condition, which provides a perfect platform to simultaneously address the efficiency and bandwidth problems. This novel feature represents a meaningful step forward to integrate spatial light modulation. [ABSTRACT FROM AUTHOR]

In order to improve the production quality of the lipstick-filling machines and the performance of the equipment, the structure of a turntable lipstick-filling machine was designed and the servo control was optimized, considering the known production defects. First, based on the lipstick-filling process, the structure of the turntable lipstick-filling machine was designed. Regarding the bubble problem in lipstick filling, an elastic connecting rod vibration device was designed. Based on the principle of PMSM and a position servo system, a mathematical model of the lipstick-filling servo system was established, the system transfer function was calculated and its dynamic performance was analyzed. Combined with the transfer function, the lipstick-filling servo system PID control and particle swarm optimization PID control simulation models were built. The system adjustment time ts was 0.7 s under particle swarm optimization. Finally, a prototype was built to verify the simulation optimization results. The experimental results demonstrate that the qualified rate of lipstick filling, under the particle swarm optimization PID control implementation, is 97%, indicating that the particle swarm algorithm is quite applicable and has an economic impact by improving the accuracy and stability of the lipstick-filling servo system. [ABSTRACT FROM AUTHOR]

The prevalence of inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), increases gradually worldwide in the past decades. IBD is generally associated with the change of the immune system and gut microbiota, and the conventional treatments usually result in some side effects. Bifidobacterium longum, as colonizing bacteria in the intestine, has been demonstrated to be capable of relieving colitis in mice and can be employed as an alternative or auxiliary way for treating IBD. Here, the mechanisms of the Bifidobacterium longum in the treatment of IBD were summarized based on previous cell and animal studies and clinical trials testing bacterial therapies. This review will be served as a basis for future research on IBD treatment. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical reduction of CO2 to value‐added chemicals by using renewable electricity offers a promising strategy to deal with rising CO2 emission and the energy crisis. Single‐site zinc‐coordinated nitrogen‐codoped graphene (Zn–N–G) catalyzes the electrochemical reduction of CO2 to CO. The Zn–N–G catalyst exhibits excellent intrinsic activity toward CO2 reduction, reaching a faradaic efficiency of 91 % for CO production at a low overpotential of 0.39 V. X‐ray absorption fine structure and X‐ray photoelectron spectroscopy both confirm the presence of isolated Zn–Nx moieties, which act as the key active sites for CO formation. DFT calculations reveal the origin of enhanced activity for CO2 reduction on Zn–N–G catalysts. This work provide further understanding of the active centers on transition metal–nitrogen–carbon (M–N–C) catalysts for electrochemical reduction of CO2 to CO. [ABSTRACT FROM AUTHOR]

Portal hypertension is a frequent pathological symptom occurring especially in hepatic fibrosis and cirrhosis. Current paradigms indicate that inhibition of hepatic stellate cell (HSC) activation and contraction is anticipated to be an attractive therapeutic strategy, because activated HSC dominantly facilitates an increase in intrahepatic vein pressure through secreting extracellular matrix and contracting. Our previous in vitro study indicated that dihydroartemisinin (DHA) inhibited contractility of cultured HSC by activating intracellular farnesoid X receptor (FXR). However, the effect of DHA on fibrosis-related portal hypertension still requires clarification. In this study, gain- and loss-of-function models of FXR in HSC were established to investigate the mechanisms underlying DHA protection against chronic CCl4-caused hepatic fibrosis and portal hypertension. Immunofluorescence staining visually showed a decrease in FXR expression in CCl4-administrated rat HSC but an increase in that in DHA-treated rat HSC. Serum diagnostics and morphological analyses consistently indicated that DHA exhibited hepatoprotective effects on CCl4-induced liver injury. DHA also reduced CCl4-caused inflammatory mediator expression and inflammatory cell infiltration. These improvements were further enhanced by INT-747 but weakened by Z-guggulsterone. Noteworthily, DHA, analogous to INT-747, significantly lowered portal vein pressure and suppressed fibrogenesis. Experiments on mice using FXR shRNA lentivirus consolidated the results above. Mechanistically, inhibition of HSC activation and contraction was found as a cellular basis for DHA to relieve portal hypertension. These findings demonstrated that DHA attenuated portal hypertension in fibrotic rodents possibly by targeting HSC contraction via a FXR activation-dependent mechanism. FXR could be a target molecule for reducing portal hypertension during hepatic fibrosis. [ABSTRACT FROM AUTHOR]