Existing cross-correlation mitigation algorithms based on the minimum mean square error (MMSE) criterion can effectively suppress multiple access interference (MAI) but suffer from high complexity ...and modeling grid mismatch. In this work, we propose a cell-straddling robust-fast cross-correlation mitigation (CSR-FCCM) algorithm with two improvements. First, CSR-FCCM combines the 2-D joint iterative adaptive filtering with interference cancellation, which significantly reduces the number and computational cost of complex amplitude MMSE filters. Second, two discriminators are designed to estimate the straddling offset of delay and frequency for the direct sequence spread spectrum signal. The mismatch problem can be ameliorated by substituting estimated straddling offsets into the signal model, which further improves the MAI mitigation effect. The effectiveness of the CSR-FCCM is verified by simulations using 1023- and 63-length gold codes. Simulation results show that CSR-FCCM has a better MAI mitigation performance and a lower complexity than the open-loop MAI mitigation algorithms, including 2-D jointly iterative adaptive filter and RSR-APC.
China has a long history of eating staple plant foods which are mainly derived from food grains, especially rice and wheat. Food grain safety has been a worrying challenge on health and nutrition ...grounds in China, although evidence clearly suggests that expanding agricultural production is linked to reducing undernourishment. The focus of this study is to investigate consumers’ anxieties about food grain safety in China. The nature and extent of consumer anxieties about grain safety, the cause of these anxieties, and possible ways to relieve anxiety are empirically analyzed. Data were collected using semi-structured interviews with 142 grain consumers in 29 provinces of China, in both rural and urban areas, during 2016. The results show that consumers are worried about the production and processing safety of food grains and genetically modified cereals and that the causes of anxiety are varied. Anxiety is amplified by social media reports of food scandals, polluted ecological environments, the high incidence of food-related chronic diseases and cancer, concerns about food system governance and lack of knowledge and ability to identify grain quality. Consumers seek to relieve their anxiety by identifying grain quality themselves, choosing foreign grains and paying close attention to reports about unsafe food. These findings have important implications for future programs aimed at improving consumer confidence about grain safety.
•This paper explores food grain safety from a consumer perspective in China.•The paper shows that consumer anxieties are a social phenomenon.•Data were collected using semi-structured interviews with consumers.•The paper outlines the nature of consumer anxieties about grain safety.
The asymmetric synthesis of bridged tetrahydrobenzobazepine and oxepine derivatives through chiral Brønsted acid catalyzed asymmetric aza-Piancatelli rearrangement/Michael addition sequence has ...been developed. The reaction proceeds under mild reaction conditions to afford the final bridged cyclic products in good yields with excellent enantio- and diastereoselectivities.
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The MnO2@ZIF-8 core–shell nanoparticles for highly efficient dye degradation have been synthesized with a green method. ZIF-8 crystals with controlled morphology and size are first ...synthesized by using peptide to modulate the crystal growth. MnO2 is then coated on ZIF-8 via in situ reaction. The surface MnO2 density can be controlled by the dosage of KMnO4. The MnO2@ZIF-8 nanoparticles work as photocatalyst to degrade rhodamine B in a Fenton-like process, giving a degradation ratio of > 96.0%. The degradation kinetics comply well with the Pseudo-second-order model and the experimental equilibrium data meet the Langmuir model best. The specific hierarchical structure of MnO2@ZIF-8 assures a synergistic enhancement of the catalytic degradation performance from several aspects. First, anchoring of the MnO2 nanoparticles on ZIF-8 allows their well disperse to provide more active surface area. Second, highly porous ZIF-8 can adsorb dye molecules to accumulate them at the surface reactive sites. Third, the MnO2/ZIF-8 nano-heterojunctions enhance charge carrier transfer and accelerate the production of free oxidative radicals. The study demonstrates a green method for fabrication of hierarchical hybrid structures, paving the way for designing novel photocatalysts with potential applications for wastewater treatment.
Chemical solution deposition is becoming one of the most promising routes toward cost-effective production of REBa2Cu3O7−z (REBCO) based high temperature superconducting tapes. However, a ...comprehensive understanding of nucleation and growth for REBCO films with dopants, especially considering low sintering temperature and high reproducibility, is still far from being achieved. In this work, dilute Co was introduced into fluorine-free precursor, and comparison studies of a set of pristine and doped GdBCO films were carried out. Correlation between texture, microstructure and critical current density were established, and nucleation & growth mechanism for doped films were proposed. By comparison, Co doping enables to reduce the textured temperature about 50 ℃ because of the dramatically decreased decomposition temperature of intermediate phase BaCO3, which facilitate Ba-Cu-O liquid phase transformation and thus GdBCO epitaxial growth at lower temperatures. These results bring particular opportunities for fine tuning of the film fabrication process by incorporating dilute impurities in precursors.
•Dilute Co doping enables to reduce the textured temperature about 50 ℃.•Doped films possess stronger c-axis texture and better grains connectivity at the same sintering temperature.•The decomposition temperature of BaCO3 is obviously reduced with Co doping, facilitating Ba-Cu-O transition to GdBCO.•BaCO3 conversion mainly determines the nucleation and crystallization of GdBCO c-axis grains.
It is vital to search for highly efficient bifunctional oxygen evolution/reduction reaction (OER/ORR) electrocatalysts for sustainable and renewable clean energy. Herein, we propose a single ...transition-metal (TM)-based defective AlP system to validate bifunctional oxygen electrocatalysis by using the density functional theory (DFT) method. We found that the catalytic activity is enhanced by substituting two P atoms with two N atoms in the Al vacancy of the TM-anchored AlP monolayer. Specifically, the overpotential of OER(ORR) in Co- and Ni-based defective AlP systems is found to be 0.38 (0.25 V) and 0.23 V (0.39 V), respectively, showing excellent bifunctional catalytic performance. The results are further presented by establishing the volcano plots and contour maps according to the scaling relation of the Gibbs free-energy change of *OH, *O, and *OOH intermediates. The d-band center and the product of the number of d-orbital electrons and electronegativity of the TM atom are the ideal descriptors for this system. To investigate the activity origin of the OER/ORR process, we performed the machine learning (ML) algorithm. The result indicates that the number of TM-d electrons (
), the radius of TM atoms (
), and the charge transfer of TM atoms (
) are the three primary descriptors characterizing the adsorption behavior. Our results can provide a theoretical guidance for designing highly efficient bifunctional electrocatalysts and pave a way for the DFT-ML hybrid method in catalysis research.
The effects of various physical state lipids (rapeseed oil (RO), shortening (ST), beeswax (BW)), on the physicochemical properties of starch (S) (hydroxypropyl distarch phosphate (HP), oxidized ...hydroxypropyl starch (OS))/gelatin (G) blown films were studied. S/G-lipid blends showed decreased storage modulus and complex viscosity. The formation of hydrogen bonds was inhibited by the ST and BW, but facilitated by the RO. Compared with BW and ST, RO was more effective to promote the melted and fractured of starch. Lipids addition promoted the compatibility of starch and gelatin. The presence of the lipids significantly improved the surface hydrophobicity, mechanical, water vapor barrier and water resistance properties of S/G films. S/G-RO films exhibited the strongest surface hydrophobicity and tensile strength, while HP/G-BW film showed the strongest water resistance and water vapor barrier properties. These results revealed that the appropriate lipids could be used to produce S/G-lipid films with desirable physicochemical properties.
•Effects of different physical state lipids on blown S/G films were studied.•Lipids addition facilitated the compatibility of starch and gelatin.•The TS and EAB of films simultaneously increased in the presence of lipids.•HP/G film with the addition of RO formed a hydrophobic film surface.
•CS@BPNSs@CuNPs can help postoperative hemostasis (24.98 %) and catch residual cells.•The hydrogel generated high ROS for antibacterial (98.1 %) and anticancer (11.3 %).•The combination of hydrogel ...and aPD-L1 showed a synergistic therapeutic effect.•The biodegradable hydrogel could cross blood tumor barrier to treat glioblastoma.
Wound bacterial infections and tumor recurrence are the main reasons for the poor prognosis after primary tumor resection. Here, we fabricated a novel therapeutic nanocomposite using chitosan (CS) hydrogel combined with black phosphate nanosheets (BPNSs) and in situ grown copper nanoparticles (CuNPs). The obtained hydrogel (CS@BPNSs@CuNPs), possessing a remarkable temperature-sensitive spongy-like state, offered 24.98 % blood clotting index. The released BPNSs@CuNPs could produce reactive oxygen species (ROS) to kill infected invasive bacteria (98.1 %) and inhibit local residual tumor cell regeneration (11.3 %). Moreover, by coupling the photothermal properties of BPNSs, the BPNSs@CuNPs showed 19.6 % penetration rate to cross the blood tumor barrier (BTB) for treating brain tumors. The hydrogel platform was further combined with aPD-L1-based immunotherapy to employ its synergetic therapeutic effect in the prevention of tumors. The in vivo studies showed that biodegradable hydrogel could hold a great potential as a novel strategy for improving postoperative therapy and multi-tumor treatments.
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