Search

Aiming at the low tracking accuracy and poor fault tolerance of displacement-controlled systems, this paper puts forward a fault tolerant robust controller. The influence of many uncertain factors on trajectory tracking performance have been considered, such as external disturbances, high nonlinearity, system faults, and complex modeling uncertainty of the system. First, a new finite-time observer is proposed to estimate the system states, disturbances, and system faults simultaneously. Then, an improved fast super twisting algorithm is designed to guarantee the reachability of the sliding surface in finite time. Furthermore, the prescribed performance constrained control technique is combined to ensure that the tracking error remains within the prescribed bounded range even though faults occur. Finally, the effectiveness of the proposed control method is validated by simulation results. [Display omitted] • Fault-tolerant control problems of the displacement-controlled systems are solved. • By the new finite-time observer, the finite-time convergent property is guaranteed. • By an improved super twisting algorithm, the fast dynamic performance is ensured. • By prescribed performance control, the transient and steady performance is ensured. [ABSTRACT FROM AUTHOR]

• The macro and micro performances of the cutter ring in TBM were tested. • The impact fracture failure causes of the cutter ring and the effect of texture on the performance are analyzed. • A model for cutter ring impact fracture failure is established. • Some suggestions for improve the production process of cutter ring are proposed. The fracture of the disc cutting ring significantly impedes the efficiency of TBM. This phenomenon is particularly obvious in geological conditions with high impact loads, such as fracture zones and extremely hard rock areas. In these environments, the incidence of disc cutter ring fracture failure escalates dramatically. To explore the impact fracture failure causes and mechanisms of the disc cutter ring under high impact loads, and to guide the improvement of cutter ring manufacturing process, an in-depth analysis was conducted. The chemical composition, tensile strength, hardness, impact toughness, structure morphology and impact specimen fracture morphology of the cutter ring from a TBM project were measured and analyzed. The results show that the tensile strength point of the disc cutter ring coincides with the fracture point, demonstrating that the ring has an extremely strong brittleness. The impact toughness of the surface of the disc cutter ring is lower than that of the inside, and cracks are easy to start on the surface of the disc cutter ring. According to the microstructure analysis, there are coarse Al-rich inclusions precipitated between grains, accompanied by microcracks and microvoids, which reduce the mechanical properties of the disc cutter ring. Through the fracture morphology analysis, the type of the disc cutter ring impact fracture is a mixture of quasi-cleavage, cleavage and intergranular. When a very high impact load is applied, cracks first nucleate at hard points such as coarse carbides, Al-rich inclusions and voids, and then the main crack propagates in a tortuous manner parallel to the force direction. [ABSTRACT FROM AUTHOR]

The recent development of 3D printing techniques enables novel applications in customized food fabrication. Based on a tailor-made 3D food printer, we present a novel personalized food printing framework driven by portrait images. Unlike common 3D printers equipped with materials such as ABS, Nylon and SLA, our printer utilizes edible materials such as maltose, chocolate syrup, jam to print customized patterns. Our framework automatically converts an arbitrary input image into an optimized printable path to facilitate food printing, while preserving the prominent features of the image. This is achieved based on two key stages. First, we apply image abstraction techniques to extract salient image features. Robust face detection and sketch synthesis are optionally involved to enhance face features for portrait images. Second, we present a novel path optimization algorithm to generate printing path for efficient and feature-preserving food printing. We demonstrate the efficiency and efficacy of our framework using a variety of images and also a comparison with non-optimized results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Citronella oil and Rhodojaponin-III have intense oviposition-deterring activity. [•] Bdor Orco and Bdor OBP were involved in the detection of volatile oviposition repellents. [•] Silencing the expression of Bdor Orco resulted in disoriented oviposition behaviors induced by two repellents. [Copyright &y& Elsevier]

The sustainability of winter wheat (Triticum aestivum L.) − summer maize (Zea mays L.) rotation (W − M), which is commonly practiced in the North China Plain (NCP), is threatened by severe groundwater deficits and environmental pollution due to excessive nitrogen (N) applications. Considering the need for protein-rich forages by local livestock operations and the environmental benefits of growing perennial legumes, we propose that an alfalfa (Medicago sativa L.)-based system is worth introducing for field practice in the NCP. An integrated evaluation was used in this four-year study to compare the agronomic, economic, and environmental performances of the following four cropping patterns: alfalfa monoculture (AA), alfalfa and silage maize intercropping with or without N input which is designed for local climate condition, maize monoculture with or without N input which is much-discussed as a resources-saving substitution and commonly practiced W − M. W − M obtained the highest aboveground dry matter (DM) productivity (P < 0.05) based on the highest irrigation water and N fertilizer consumption (P < 0.05) which caused considerable soil mineral N (Nmin) accumulation. The production cost of maize monoculture was the lowest as well as the DM yield, nitrogen accumulation and the net revenue compared with other systems (P < 0.05), moreover, there was a great risk of N losses during the offseason period. The alfalfa and silage maize intercropping with a low N input (120 kg ha−1 which is close to local practice for maize season) achieved 26.6%–34.9% more DM yield compared with AA and maize monoculture, and 12.5%–163.9% more N output compared with W − M and maize monoculture during four experimental years with same total economic revenue as W − M and AA did. The N input in alfalfa and silage maize intercropping dramatically improved the system productivity by assisting intercropped maize growth while did not lead to excessive Nmin accumulation within 0–210 soil layer compared with the intercropping system without N addition. The planting of alfalfa would not affect the water storage in the 0–60 soil layer after maize harvesting each year. For the effects of interspecific competition, the production of the intercropped alfalfa and maize was significantly decreased in 2020 and a three-year period of production is recommended for optimal use of the alfalfa and silage maize intercropping. Alfalfa and silage maize intercropping with an appropriate N input, which acquired comprehensive performances in terms of productivity, environmental impacts as well as economic profits, would be an optimal alternative system in the NCP. The alfalfa and silage maize intercropping with an appropriate N input (A + M), which achieved high dry matter yield, nitrogen uptake and net revenue with the lowest irrigation water and nitrogen fertilizer use, would be an optimal alternative system in the North China Plain. [Display omitted] • The wheat–maize rotation (W – M) in the North China plain is profitable but has inevitable negative environmental impacts. • Alfalfa and maize intercropping (A + M) was proposed for the high protein productivity and the adaptability to climate. • The agronomic, economic, and environmental performances were compared among A + M, W – M, and monoculture systems. • A + M was more productive than monoculture, and consumed lower groundwater and nitrogen than W–M without net revenue loss. • A + M would be an optimal alternative system in the North China Plain for its comprehensive performances. [ABSTRACT FROM AUTHOR]

• This review assessed the contamination levels of PAE in various ecosystems. • Overviewed the current status of PAE-degrading bacterial isolates and communities. • Discussed the challenges for understanding in situ PAE biodegradation mechanisms. • Proposed a guide of building synthetic community to decipher interaction mechanism. The extensive use of phthalic acid esters (PAEs) has led to their widespread distribution across various environments. As PAEs pose significant threats to human health, it is urgent to develop efficient strategies to eliminate them from environments. Bacteria-driven PAE biodegradation has been considered as an inexpensive yet effective strategy to restore the contaminated environments. Despite great advances in bacterial culturing and sequencing, the inherent complexity of indigenous microbial community hinders us to mechanistically understand in situ PAE biodegradation and efficiently harness the degrading power of bacteria. The synthetic microbial ecology provides us a simple and controllable model system to address this problem. In this review, we focus on the current progress of PAE biodegradation mediated by bacterial isolates and indigenous bacterial communities, and discuss the prospective of synthetic PAE-degrading bacterial communities in PAE biodegradation research. It is anticipated that the theories and approaches of synthetic microbial ecology will revolutionize the study of bacteria-driven PAE biodegradation and provide novel insights for developing effective bioremediation solutions. [ABSTRACT FROM AUTHOR]

• The production of monocultured alfalfa is limited in hot-rainy seasons. • An alfalfa–silage maize relay intercropping system was developed and evaluated. • Nitrogen (N) input enhanced the yield and N uptake of maize in the intercropping system. • Spring forage production of the intercropped alfalfa was unaffected in most cases. • The system with a maize plant density of 45,000 plants ha–1 fertilized at 120 kg N ha–1 was recommended in the North China Plain. Sustainable production of high-yielding and high-quality forages such as alfalfa (Medicago sativa L.) is critically important for fast-growing animal husbandry regions such as the North China Plain (NCP). Alfalfa production in this region is limited during the hot-rainy summer period from July–September, but these conditions may allow the production of intercropped silage maize (Zea mays L.) following spring harvests of alfalfa to boost the overall forage production. In this study, an alfalfa–silage maize (AM) relay intercropping system was evaluated in a field experiment from 2017 to 2019 to assess the impact of maize nitrogen (N) fertilization rates of 0, 60, 120, and 180 kg N ha–1 and maize plant densities of 30,000, 45,000, and 60,000 plants ha–1 on the forage yield and N uptake. The AM system was compared with alfalfa monocropping (AA) and silage maize monocropping (MM) controls. The 3-yr average land equivalent ratio (LER) and land equivalent ratio for nitrogen yield (LER N) of AM ranged from 1.05 to 1.37 relative to AA and MM, indicating that intercropping was advantageous for improving the overall forage production and N utilization. Intercropping reduced the maize yield by 23–30 % and the maize N yield by 26–35 % compared with the monocultured maize across 3 years. Increasing N fertilization and maize plant density often enhanced the maize yield and N uptake in the AM system. The alfalfa stand density in AM was negatively affected by the increased maize plant density and was 30–55 % lower than that in AA. Spring forage production of alfalfa in the AM and AA systems was similar in most cases, but yields in the AM system were reduced in 2018 and 2019 when maize was grown with the highest N rate (180 kg N ha–1) and the highest plant density (60,000 plants ha–1). On the basis of the system yield, N yield, and LER, the AM system with a maize plant density of 45,000 plants ha–1 fertilized at 120 kg N ha–1 was the most advantageous and could be recommended as an alternative cropping system in the NCP to increase forage yields with a relatively low input of N. [ABSTRACT FROM AUTHOR]

Abstract: Chemosensory proteins (CSPs) are small soluble proteins endowed with heterogeneous functions. The information so far available for CSPs suggested these well-defined and conserved proteins were involved in diverse activities, including chemical communication, feeding, development, mating, immune regulation, as well as circadian rhythms. However, the detailed mechanisms of these physiological functions remain elusive. To explore the underlying mechanisms of CSPs and their interaction partners, a cDNA library from the head of Plutella xylostella was screened against CSP1 to identify proteins involved in the PxylCSP1-related physiological activities. Protein kinase C (PKC) was screened out as a putative interacting protein of PxylCSP1. The full length of PxylPKC cDNA was obtained, and the results of semi-quantitative real-time PCR and quantitative real-time PCR revealed that PxylPKC showed similar expression pattern as PxylCSP1. In vivo and in vitro interactions between PxylCSP1 and PxylPKC were further confirmed by co-immunoprecipitation and GST pull-down assays, respectively. These findings extended our knowledge on the mechanisms of CSP-regulated functions, and providing new target proteins to facilitate the design of novel intervention strategies against the pest. [Copyright &y& Elsevier]

Forage sorghum (FS; Sorghum bicolor (L.) Moench) is growing in popularity as an important forage crop replaced corn ( Zea mays L.) in semi-arid regions of the world. FS can further be divided into white midrib (WMR), green midrib (GMR) and brown midrib (BMR) populations based on the color of leaf midrib. Understanding expression of nutritive values in different FS populations is essential to the breeding and utilization of the new FS varieties with high quality. A field experiment was conducted in 2012 and 2013 in order to analyze the change regulation of nutritive values and compare the differences in photosynthetic indexes and anatomy parameters among WMR, GMR, BMR-6 and BMR-12 forage sorghum populations. The results showed that there were significant ( P < 0.05) differences in nutritive values and anatomy parameters between BMR and other FS populations whereas no differences ( P > 0.05) were observed in photosynthetic indexes. When compared with non-BMR populations (WMR and GMR), the mean ADL, NDF and ADF content of BMR populations (BMR-6 and BMR-12) were decreased respectively by 28.0%, 4.1% and 5.8% while the mean CP content was increased by 8.0% during the two years. Especially, BMR-12 populations had significantly ( P < 0.05) lower ADL content and higher CP content than that of BMR-6 based on their dynamic curve regression model. The nutritive values of forage sorghum populations were ranked as following order: BMR-12 > BMR-6 > GMR > WMR. In conclusion, the BMR populations, particularly BMR-12, had exhibited consistently higher nutritive values since joint stage (the average plant height was about 130 cm). This result further reinforces the advantages of BMR gene effect in populations and also will provide scientific data for rational utilizing BMR forage sorghum resources in practice. [ABSTRACT FROM AUTHOR]

The Dirac cone structure of the energy band of the single-layer graphene gives rise to ambipolar conduction which results from the conversion of the conductive carriers in graphene between electrons and holes under the effect of the electrical field. Therefore, the graphene field-effect transistor (GFET) exhibits a V-shaped transfer characteristic curve with an electron and hole conduction branch converting at a conductance minimum. However, in this paper, unique W-shaped σ – V g curve with double conductance minima instead of the typical V-shaped one is observed in GFET based on chemical vapor deposition grown graphene, demonstrating a graphene p–n junction behavior. The observation is not expected from the energy band structure of graphene and probably results from the doping effect of the metal contact on the underlying graphene, which leads to a misalignment of the Fermi level between graphene under the metal contact and in the channel area, and ultimately induces the double conductance minima because of the formation of the graphene p–n junction. [ABSTRACT FROM AUTHOR]

Temperature (T) and gate voltage sweep range (V [ABSTRACT FROM AUTHOR]

Abstract: We report the structural and enhanced ferromagnetic properties of Mg doped Bi0.8Ca0.2FeO3 ceramics. Oxygen vacancies are introduced into Bi0.8Ca0.2Fe1−x Mg x O3 ceramics doping confirmed by XRD and Raman spectra, which induce a significantly enhanced macroscopic ferromagnetism from antiferromagnetism to ferromagnetism. The enhanced ferromagnetism can be ascribed to the creation of unbalanced Fe3+ spins induced by the collapse of the space modulated cycloidal spin structure and relative long-range coupling mediated by the oxygen vacancies trapped localized electrons. The improved ferromagnetic properties obtained by co-doping demonstrate the possibility of bulk BFO in practical multiferroic applications. [Copyright &y& Elsevier]

Abstract: Specific behaviors of insects are stimulated by the recognition of chemicals in the external environment by sensilla on chemoreceptive organs. Rhodojaponin III is a nonvolatile natural botanical insecticide, which has an intense effect of deterring oviposition activity against many insects. This study aimed to determine whether the Or83b protein is involved in the recognition of rhodojaponin III. The SlOr83b protein has a conserved seven-transmembrane domain and a putative receptor/receptor interaction loop. The Or83b mRNA is first transcribed in 1st larvae, and expressed in later larval stages. A high level of Or83b mRNA is expressed in pupal and adult stages. Knockdown of SlOr83b expression was achieved through RNAi by injecting double-stranded RNA (dsRNA) into the 8th day pupae, and oviposition significantly increased on rhodojaponin III treated cabbage leaves. These results suggest that Or83b is critical for insects to identify the nonvolatile the insecticide rhodojaponin III. [Copyright &y& Elsevier]