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Abstract Ferroelectrics are essential in memory devices for multi-bit storage and high-density integration. Ferroelectricity mainly exists in compounds but rare in single-element materials due to their lack of spontaneous polarization in the latter. However, we report a room-temperature ferroelectricity in quasi-one-dimensional Te nanowires. Piezoelectric characteristics, ferroelectric loops and domain reversals are clearly observed. We attribute the ferroelectricity to the ion displacement created by the interlayer interaction between lone-pair electrons. Ferroelectric polarization can induce a strong field effect on the transport along the Te chain, giving rise to a self-gated ferroelectric field-effect transistor. By utilizing ferroelectric Te nanowire as channel, the device exhibits high mobility (~220 cm2·V−1·s−1), continuous-variable resistive states can be observed with long-term retention (>105 s), fast speed (1.92 TB/cm2). Our work provides opportunities for single-element ferroelectrics and advances practical applications such as ultrahigh-density data storage and computing-in-memory devices.

Under the interaction between natural ecosystems and human interferences, farmland extends to multi-functions such as production, ecological, social, and cultural functions. Despite the exponential increase in research on the multi-functional evaluation of farmland in recent years, little study has been conducted at fine spatial and long-time scales. Furthermore, the existing quantitative analyses of multifunctional synergies and trade-offs in farmland mainly consider static spatial patterns and neglect dynamic information. Selecting the Chinese coastal province of Zhejiang as the study area, this study thus evaluated the spatio-temporal patterns of farmland functions from 2000 to 2020 at the county scale and introduced the trade-off/synergy degree (TSD) model to quantify the intensity of the relationships among functions. The results showed that farmland functional values and their relationships were significantly heterogeneous in spatial and temporal distribution. In addition to social function, the other functions all exhibited an increasing trend. Furthermore, strong correlations were mainly observed between production, ecological and cultural functions. Ultimately, five farmland zones were determined by the k-means clustering algorithm and considering both functional values and their relationships, and targeted suggestions applicable to each zone were put forward in this study. This study contributes to the utilization and planning of farmland and its surrounding land, especially to the improvement of the policy of returning farmland to forests.

In this study, we integrated the wide-bandgap material TiO _2 as a photosensitive layer with the WSe _2 /2DEG heterostructure, creating a hybrid WSe _2 /TiO _2 /2DEG heterojunction. This hybrid structure significantly improves the device’s photosensitivity, exhibiting a high rectification effect and a switching ratio of 10 ^3 . The photodetector shows excellent performance, with a responsivity of 0.61 A W ^−1 and a detectivity of up to 1.1×10 ^11 Jones at 405 nm, along with a very fast photoresponse speed. The buried TiO _2 channel allows photogenerated electrons to easily flow through the reduced barrier at the depleted region. This hybrid heterojunction holds promise for the development of high-performance photoelectric devices.

Negative pressure tailors the physical properties of functional oxide materials. Here, the authors demonstrate an emergent multiferroism with magnetodielectric coupling in EuTiO3 created by a negative pressure control of strong spin-phonon coupling.

Two-dimensional electron gas (2DEG) at the (100) KTaO3(KTO) surface and interfaces has attracted extensive interest because of its abundant physical properties. Here, light illumination-induced semiconductor–metal transition in the 2DEG at the KTO surface was investigated. 2DEG was formed at the surface of KTO by argon ion bombardment. The 2DEG prepared with a shorter bombardment time (300 s) exhibits semiconducting behavior in the range of 20~300 K in the dark. However, it shows a different resistance behavior, namely, a metallic state above ~55 K and a semiconducting state below ~55 K when exposed to visible light (405 nm) with a giant conductivity increase of about eight orders of magnitude at 20 K. The suppression of the semiconducting behavior is found to be more pronounced with increasing light power. After removing the illumination, the resistance cannot recover quickly, exhibiting persistent photoconductivity. More interestingly, the photoresponse of the 2DEG below 50 K was almost independent of the laser wavelength, although the photon energy is lower than the band gap of KTO. The present results provide experimental support for tuning oxide 2DEG by photoexcitation, suggesting promising applications of KTO-based 2DEG in future electronic and optoelectronic devices.

Concomitant traumatic brain injury accelerates bone healing, but the mechanism is unclear. Here, the authors show that injured neurons, mainly those in the hippocampus, release osteogenic miRNA-enriched small extracellular vesicles, which targete osteoprogenitors to stimulate bone formation.

Incorporation of supramolecular macrocycles into porous organic polymers can increase uptake of guest molecules through host−guest interactions. Here the authors report a pillar[5]quinone derived multi-microporous organic polymer, which show a superior performance in radioactive iodomethane capture and storage.

The high concentration of fine particulate matter (PM2.5) has always been a key indicator affecting Chinese environmental quality and a core factor restricting sustainable development. This article refers to the implementation of Air Pollution Prevention and Control Action Plan, analyzes the spatiotemporal variation characteristics of PM2.5 health risks in 247 cities in China from 2015 to 2017, and divides the cities into four types by the interannual variation differences in health risks: cities with PM2.5 health risks continuously decreased (hereinafter referred to as I type cities), cities with PM2.5 health risks continuously increased (Ⅱ type cities), cities with unknown changes of PM2.5 health risks (IIItype cities), and cities with irregular changes of PM2.5 health risks (Ⅳ type cities). The STIRPAT model and cross-sectional regression method are used to explore the influence and difference in socioeconomic drivers on PM2.5 health risks in types of cities. The results show that (1) Chinese PM2.5 health risks decreased by 3% from 2015 to 2017. According to the change characteristics of health risks, the cities are divided into four types of cities. And the distribution of the four types of cities is regional. (2) From the perspective of drivers, all the cities with PM2.5 health risks are vulnerable to the impact of human activities in built-up areas. I type cities have high per capita GDP and low energy consumption per unit GDP, indicating that the economic development of these cities has low dependence on energy. Ⅱ type cities are easily affected by urbanization rate. The highway mileage has the greatest impact on III type cities. In Ⅳ type cities, the proportion of secondary industry is the smallest, but it is easily affected by the proportion of secondary industry. This study provides theoretical support for the fine control of PM2.5 pollution in each city.

Gas sensing performance characterization systems are essential for the research and development of gas sensing materials and devices. Although existing systems are almost completely automatically operated, the accuracies of gas concentration control and of pressure control and the ability to simultaneously detect different sensor signals still require improvement. In this study, a high-precision gas sensing material characterization system is developed based on vacuum technology, with the objective of enabling the precise and simultaneous measurement of electrical responses. Because of the implementation of vacuum technology, the gas concentration control accuracy is improved more than 1600 times, whereas the pressure of the test ambient condition can be precisely adjusted between vacuum and 1.2 bar. The vacuum-assisted gas-exchanging mechanism also enables the sensor response time to be determined more accurately. The system is capable of performing sensitivity, selectivity, and stability tests and can control the ambient relative humidity in a precise manner. More importantly, the levels of performance of three different optical signal measurement set-ups were investigated and compared in terms of detection range, linearity, noise, and response time, based on which of their scopes of application were proposed. Finally, single-period and cyclical tests were performed to examine the ability of the system to detect optical and electrical responses simultaneously, both at a single wavelength and in a spectral region.

Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the heavy metal (HM) contamination level of dairy slurry. The effects of UAEO operating parameters on digestion efficiency were tested based on Cu and Zn concentrations in a dairy slurry sample. The results showed that Cu and Zn digestion efficiency was (96.8 ± 2.6) and (98.5 ± 2.9)%, respectively, with the optimal UAEO operating parameters (digestion time: 45 min; ultrasonic power: 400 W; NaCl concentration: 10 g/L). The digestion recovery rate experiments were then operated with spiked samples to verify the digestion effect on broad-spectrum HMs. When the digestion time reached 45 min, all digestion recovery rates exceeded 90%. Meanwhile, free chlorine concentration, particle size distribution, and micromorphology were investigated to demonstrate the digestion mechanism. It was found that 414 mg/L free chorine had theoretically enough oxidative ability, and the ultrasound intervention could deal with the blocky undissolved particles attributed to its crushing capacity. The results of particle size distribution showed that the total volume and bulky particle proportion had an obvious decline. The micromorphology demonstrated that the ultrasound intervention fragmented the bulky particles, and electrochemical oxidation made irregular blocky structures form arc edge and cellular structures. The aforementioned results indicated that UAEO was a novel and efficient method. It was fast and convenient. Additionally, it ensured digestion efficiency and thus had a good application prospect.

The removal of soluble cyclic ether contaminants, such as dioxane and THF, produced in industrial chemical processes from water is of great importance for environmental protection and human health. Here we report that nonporous adaptive crystals of perethylated pillar[5]arene (EtP5) and pillar[6]arene (EtP6) work as adsorbents for cyclic ether contaminant removal via host-guest complexation at the solid-solution interface. Nonporous EtP6 crystals have the ability to adsorb dioxane from water with the formation of 1:2 host-guest complex crystals, while EtP5 crystals cannot. However, both guest-free EtP5 and EtP6 crystals remove THF from water with EtP5 having a better capacity. This is because EtP5 forms a 1:2 host-guest complex with THF via host-guest complexation at the solid-solution interface while EtP6 forms a 1:1 host-guest complex with THF. EtP6 also shows the ability to selectively remove dioxane from water even in the presence of THF. Moreover, the reversible transitions between nonporous guest-free EtP5 and EtP6 structures and guest-loaded structures make them highly recyclable.

In this work, Ca _3 Ti _2 O _7- _x F _x thin films on (110) SrTiO _3 substrates were prepared by two steps as deposited via pulsed laser deposition and fluorinated with polyvinylidene fluoride. Despite the unchanged crystal structure of the fluorinated films, the changed valence state can be used to confirm the incorporation of F ^−1 and the weakened chemical bond of Ca–O. Furthermore, we found that the photoelectric switch can be observed at a wide range of light wavelength from 405 nm to 808 nm. It is found that the photosensitivity of 4 × 10 ^4 (405 nm) in the fluorine has been increased by two orders of magnitude, which is most likely due to the deep energy levels in the reduced band gap of 2.3 eV. This work paves the way for the enhanced photoconductive devices via the anionic defect engineering.

The atomic and electronic structures have been investigated for the multiferroic behavior in the perovskite oxides, which also can be tuned by oxygen vacancy for enhancing properties. Here epitaxial Sr(Ti _0.875 Fe _0.125 )O _3- _δ thin films were deposited on (001) SrTiO _3 substrates by pulsed laser deposition and were post-annealed in an oxygen atmosphere. We found that the oxygen vacancies formed in high vacuum are the source of the macroscopic crystal distortion as the growth strain along out-of-plane . Moreover, it was determined that the full-filled Fe 3 d states induced by oxygen vacancy effect are responsible for the decreased magnetization. This work demonstrates that the oxygen vacancy can both lead to atomic and electronic reconstructions in the perovskite films for manipulating ferroic properties.

In many logistics applications, densely placed objects on high-speed conveyor belts are attached with passive tags for automatic identification and sorting to work more efficiently. Traditional localization or sorting methods cannot effectively work in such scenarios due to complex environments. In this article, we propose a new passive radio frequency identification sorting system for dense mobile tags on high-speed conveyor belts by utilizing the output phase. At first, a relative motion model is utilized to get the zero point time when the object passes the radio frequency identification portal. Then, the coarse-grained time and the corresponding speed of the conveyor belt are obtained by the phase curve fitting. Finally, the inverse synthetic aperture radio frequency identification is used to get the fine-grained zero point time, which is realized based on the holographic image reconstruction. And the particle filter is utilized to get a significant reduction of computational burden. The proposed method is implemented with commercial-off-the-shelf devices, and the evaluation results in various scenarios show our system can achieve an average accuracy of 97% with the tag density of 10/m and at a speed of 4 m/s.

Material flow cost accounting (MFCA), an environmental management accounting method, is adopted to reduce the amount of wastes that result from manufacturing activities. In this paper, MFCA is introduced to study the environmental impacts of production lot-size determination by structuring simulation models of a multi-variety and small-batch production system in an actual forging factory. It is demonstrated that the proposed procedure of application of simulation with MFCA can also perform a dynamic analysis and a static analysis.

WSe2-based heterostructures are extensively enhanced by dielectric and interfacial engineering for high-performance photodetectors. However, it is difficult to integrate a magnetic three-dimensional (3D) thin film on the two-dimensional (2D) van der Waals heterostructure. In this study, a magnetic 2D p-WSe2/n-2DEG heterostructure with an inserted epitaxial SrCoO2.5 thin film is fabricated, and a p-n heterojunction is formed via an Ar+-ion-bombardment process. The fabricated device with a typical long depletion region responds to a broad spectral range from 447-808 nm within the wide temperature range of 10-300 K. In the dark and under light illumination, the magneto-optical response can be realized due to the self-charging process in the device. Furthermore, the adjustable multistate can be expected under multi-field interaction on the heterojunction, which can be controlled by the control signal as the light ON/OFF switching, bias, and magnetic field. Based on the experimental results and process simulation, it is demonstrated that the heterojunction with an optimized magnetic SrCoO2.5 design holds promise as a multimode logic gate, which can be implemented with complementary 2D/3D semiconductor design and fabrication processes. [ABSTRACT FROM AUTHOR]

[Objectives] To investigate the effects of different levels of fertilizer reduction on the occurrence of three species of wheat aphids (Schizaphis graminum, Sitobion miscanthi and Rhopalosiphum padi) and two species of wheat mites (Penthaleus major and Petrobia latens), and on wheat yield, in wheat fields in Shandong. [Methods] The population dynamics of wheat aphids and mites, which are the main crop pests in wheat fields, were studied under standard (600 kg/hm2), 10% reduced (540 kg/hm2), 20% reduced (480 kg/hm2), 37.5% reduced (375 kg/hm2) and 50% reduced (300 kg/hm2), applications of fertilizer. Yield indices (including biomass per ear, ears per meter of wheat row, seed weight per 10 ears, weight of 1 000 seeds and yield per 667 m2) under the above fertilizer levels were also investigated. [Results] The occurrence of wheat aphids and mites were reduced to different degrees by the different levels of fertilizer application. The occurrence of S. graminum and S. miscanthi were strongly, and negatively, correlated with the level of fertilizer reduction. However, the level of fertilizer application had no significant effect on the seed weight per 10 ears or per 1 000 seeds. Reducing the amount of fertilizer by 50% significantly decreased the biomass per ear, ears per meter of wheat row and yield per 667 m2. However, a regression model indicates that wheat yield is not affected when the amount of fertilizer is reduced by < 23.16%. [Conclusion] Moderate reduction in the amount of fertilizer applied to wheat fields reduces the abundance of the main wheat pests without greatly affecting wheat yield. [ABSTRACT FROM AUTHOR]