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Poly(urethane-urea) elastomers (PUUEs) have gained significant attention recently due to their growing demand in electronic skin, wearable electronic devices, and aerospace applications. The practical implementation of these elastomers necessitates many exceptional properties to ensure robust and safe utilization. However, achieving an optimal balance between high mechanical strength, good self-healing at moderate temperatures, and efficient flame retardancy for poly(urethane-urea) elastomers remains a formidable challenge. In this study, we incorporated metal coordination bonds and flame-retarding phosphinate groups into the design of poly(urethane-urea) simultaneously, resulting in a high-strength, self-healing, and flame-retardant elastomer, termed PNPU-2%Zn. Additional supramolecular cross-links and plasticizing effects of phosphinate-endowed PUUEs with relatively remarkable tensile strength (20.9 MPa), high elastic modulus (10.8 MPa), and exceptional self-healing efficiency (above 97%). Besides, PNPU-2%Zn possessed self-extinguishing characteristics with a limiting oxygen index (LOI) of 26.5%. Such an elastomer with superior properties can resist both mechanical fracture and fire hazards, providing insights into the development of robust and high-performance components for applications in wearable electronic devices.

Inorganic nanoparticles have been proved as powerful lubricant additives at elevated temperature. However, the tribological properties are inevitably impaired due to poor dispersion and insufficient high temperature resistance of organic matter modified nanoparticles. Here, we prepare a self-dispersed molybdenum disulfide quantum dot/graphene crumpled ball (MGCB) comprising molybdenum disulfide quantum dot uniformly interspersed on the wrinkled graphene ball. The crumpled ball composite possesses excellent dispersity in polyalkylene glycol base oil without depending on surface modifiers. Compared with the conventional phosphate esters lubricant, our results indicate MGCB could vastly improve the lubrication performance of polyalkylene glycol with an extremely low concentration (0.05 wt%) at elevated temperature (150 °C), showing a friction reduction of 47% and a wear reduction of 30% compared with the conventional phosphate esters lubricant (tricresyl phosphate, TCP). This is because crumpled ball potentiates synergistic lubrication effect within the boundary lubrication. Overall, we envision our designed self-dispersed MGCB has significant potential in tribological application at elevated temperature.

Nickel (Ni) nanoparticles can be enriched on the surface of iron-based frictional pairs, which provides the possibility to get rid of the competitive adsorption between the polar species of vegetable oil and the surface-active nano-additives thereon. In this paper, nickel acetylacetonate was used as a precursor to in-situsynthesize nickel nanoparticles with an average diameter of about 12 nm in rapeseed oil (RO) as the reducing agent, surface modifier, and solvent as well. The tribological properties of the as-synthesized Ni nanoparticles were evaluated with a four-ball tribometer, and their tribomechanism was investigated based on the characterizations of the tribofilm on rubbed steel surfaces by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that the Ni nanoparticles in-situprepared in the RO with a mass fraction of 0.3% can reduce the wear scar diameter (WSD) of the steel ball by 36%. This is because, on the one hand, the Ni nanoparticles are adsorbed on the rubbed steel surfaces to repair or fill up the micro-pits and grooves thereon. On the other hand, Ni nanoparticles participate in tribochemical reactions with atmospheric O and steel substrate to form the tribochemical reaction film on the rubbed steel surfaces with the assistance of friction-induced heat and applied normal load. In addition, an amorphous carbon film is formed on the rubbed surface via the carbonization of base oil under the catalysis of Ni nanoparticles. The adsorbed Ni layer, the tribochemical reaction film, and the carbon layer comprise a composite tribofilm composed of amorphous carbon, polar fatty acid, metallic nickel, iron oxides, and nickel oxides on the rubbed steel surfaces, which contributes to significantly improving the antiwear ability and load-carrying capacity of the RO for the steel–steel sliding pair.

Nanozymes are nanomaterials with enzyme-like catalytic properties. They are attractive reagents because they do not have the same limitations of natural enzymes (e.g., high cost, low stability and difficult storage). To test, optimize and compare nanozymes, it is important to establish fundamental principles and systematic standards to fully characterize their catalytic performance. Our 2018 protocol describes how to characterize the catalytic activity and kinetics of peroxidase nanozymes, the most widely used type of nanozyme. This approach was based on Michaelis–Menten enzyme kinetics and is now updated to take into account the unique physicochemical properties of nanomaterials that determine the catalytic kinetics of nanozymes. The updated procedure describes how to determine the number of active sites as well as other physicochemical properties such as surface area, shape and size. It also outlines how to calculate the hydroxyl adsorption energy from the crystal structure using the density functional theory method. The calculations now incorporate these measurements and computations to better characterize the catalytic kinetics of peroxidase nanozymes that have different shapes, sizes and compositions. This updated protocol better describes the catalytic performance of nanozymes and benefits the development of nanozyme research since further nanozyme development requires precise control of activity by engineering the electronic, geometric structure and atomic configuration of the catalytic sites of nanozymes. The characterization of the catalytic activity of peroxidase nanozymes and the evaluation of their kinetics can be performed in 4 h. The procedure is suitable for users with expertise in nano- and materials technology.

Here, we report the regiospecific hydrothiolation of electron-rich thioalkynes with exclusive stereoselectivity facilitated by an organic base, which could proceed exceedingly fast under ambient atmosphere and room temperature, affording β transaddition products in up to nearly quantitative yields. The dual nature of the sulfur atom in attracting and donating electrons is supposed to be pivotal in determining the regio- and stereoselectivity. This system tolerates a wide range of thiols and thioalkynes and shows great potential in polymer synthesis.

Organic molybdenum lubricant additive like molybdenum dialkyl dithiocarbamate (MoDTC) can cause wear acceleration of diamond-like carbon (DLC) coating coupled with steel under boundary lubrication, which hinders its industrial application. Therefore, polyisobutylene succinimide (PIBS), an organo molybdenum amide, was adopted to modify molybdenum oxide affording molybdenum polyisobutylene succinimide-molybdenum oxide nanoparticles (MPIBS-MONPs) with potential to prevent the wear acceleration of DLC coating. The thermal stability of MPIBS-MONPs was evaluated by thermogravimetric analysis. Their tribological properties as the additives in di-isooctyl sebacate (DIOS) were evaluated with MoDTC as a control; and their tribomechanism was investigated in relation to their tribochemical reactions and synergistic tribological effect with zinc dialkyldithiophosphate (ZDDP) as well as worn surface characterizations. Findings indicate that MPIBS-MONPs/ZDDP added in DIOS can significantly reduce the friction and wear of DLC coating, being much superior to MoDTC. This is because MPIBS-MONPs and ZDDP jointly take part in tribochemical reactions to form a composite tribofilm that can increase the wear resistance of DLC coating. Namely, the molybdenum amide on MPIBS-MONPs surface can react with ZDDP to form MoS2film with excellent friction-reducing ability; and MPIBS-MONPs can release molybdenum oxide nanoparticle to form deposited lubrication layer on worn surfaces. The as-formed composite tribofilm consisting of molybdenum oxide nanocrystal, amorphous polyphosphate, and molybdenum disulfide as well as a small amount of Mo2C accounts for the increase in the wear resistance of DLC coating under boundary lubrication.

Ternary hierarchical Fe3O4@C@MoS2composites and binary hierarchical Fe3O4@C composites were successfully fabricated by a modified mixed solvothermal method, a self-oxidation polymerization method, and a hydrothermal process. Their magnetic properties and microwave absorption performance were investigated. Dual resonance behavior was observed in the Fe3O4@C@MoS2composites. One of the resonances was attributed to natural resonance with a resonance frequency of 2.58 GHz, which was much higher than that for Fe3O4bulk (1.5 GHz). The other originated from the superparamagnetic/ferromagnetic relaxation with a resonance frequency of 12.45 GHz. The minimum reflection loss (RLmin) reached −64.30 dB with a matched thickness of 2.24 mm at 11.64 GHz, and the maximum effective absorption bandwidth (EABmax) covered 6.39 GHz with a matched thickness of 1.89 mm. In addition, the maximum Radar cross section (RCS) reduction value reached 31.90 dB m2at a scattering angle of 0°. Electron holography analysis confirmed a dense magnetic absorption network in the Fe3O4@C@MoS2composites. The boost in microwave absorption performance was caused by the synergistic effects of magnetic and dielectric properties owing to the ternary hierarchical structure, shape magnetic anisotropy, and incorporation of 1T/2H MoS2. Besides, the binary hierarchical Fe3O4@C composites also exhibited good absorbing performance caused by natural resonance, with an RLminof −52.90 dB at 5.80 mm, an EABmaxof 5.98 GHz at 3.38 mm, and a relatively high RCS reduction value of 13.04 dB m2at θ = 20°. This work paves the way for designing multicomponent hierarchical absorbers with broadband and intensive microwave absorption.

Single-atom catalysts with well-defined atomic structures and precisely regulated coordination environments have been recognized as potential substitutes for natural metalloenzymes. Inspired by the metal coordination structure of natural enzymes, we show here that the oxidase-like activity of single-atom Co catalysts greatly depends on their local N coordination around the Co catalytic sites. We synthesized a series of Co single-atom catalysts with different nitrogen coordination numbers (Co–Nx(C), x= 2, 3, and 4) and demonstrated that the oxidase-like activity of single-atom Co catalysts could be effectively tailored by fine-tuning the N coordination. Among the studied single-atom Co catalysts, the Co–N3(C) with three-coordinate N atoms shows the optimum oxygen adsorption structure and robust reactive oxygen species (ROS) generation, thus presenting the preferable oxidase-like catalytic activity. This work facilitates the future development of rational nanozyme designs for targeting reactions at the atomic level.

Formaldehyde (HCHO), as one of the prominent indoor pollutants, causes many health-related problems. Although the detection of HCHO is a widespread concern and a variety of detection methods have been continuously developed, the volatile organic chemical (VOC) interference remains to be solved. Here, we report a highly sensitive and selective method for HCHO detection, relying on the selective electrochemical oxidation of formaldehyde catalyzed by aldehyde dehydrogenases (ALDHs) on a Cu electrode. The detection signal exhibits a standard power law relationship against the analytes with a broad detection range of 10–5–10–15M and a limit of detection (LOD) of 1.46 × 10–15M, far below the indoor safe exposure limit (about 10–9M) for formaldehyde. In comparison to the standard spectrophotometry method, the ALDH-based electrochemical method shows a much high specificity to formaldehyde among common VOCs, such as benzene, toluene, and xylene. This simple yet effective detection technique opens up a new path for developing advanced formaldehyde sensors with high sensitivity and selectivity.

The light-emitting diodes (LED) are regarded as one of the most promising devices for inexpensive and widely used illumination; in particular, they are highly dependent on the development of red-emitting phosphors. Herein, we developed two types of red-emitting (Ba, Ca)2ScAlO5:Eu3+multiple excitations phosphors (λex= 255–465 nm) via freeze-drying followed by calcination. Powder X-ray diffraction and NMR results point out that they have hexagonal space group P63/mmc(194), and the structural framework is composed of multi-coordinated Al3+–O2–polyhedron and Sc3+–O2–polyhedron. In addition, the valence state of europium (Eu3+) is confirmed by X-ray photoelectron spectroscopy characterization. Investigation on the photoluminescence properties showed that the photoluminescence process of (Ba, Ca)2ScAlO5:Eu3+is attributable to the charge transfer band of Eu–O and abundant spectral terms of Eu3+. The α-(Ba, Ca)2ScAlO5:Eu3+and β-(Ba, Ca)2ScAlO5:Eu3+exhibited red emission under 465 and 395 nm excitation, respectively. The PL spectra and decay curves explain the intrinsic photoluminescence mechanism. The strongest emission peaks of the red-emitting α-(Ba, Ca)2ScAlO5:Eu3+and β-(Ba, Ca)2ScAlO5:Eu3+phosphors are at 615 and 619 nm, respectively, exhibiting a high fluorescence of 64 and 67% under the temperature of 423 K (150 °C). Further exploration of the red-emitting phosphors would provide a variety of choices for the design of red LEDs and white LEDs for the solid-state lighting system.

The influence of particle size and surface modifier structure on the adsorption behavior and tribological properties of surface-capped silica nano-additives in rapeseed oil was investigated. With four kinds of SiO2 nanoparticles, methyl-modified DNS-2 (particle size 14 nm) and DNS-3 (particle size 5 nm), vinyl-modified RNS-D (particle size 5 nm), and epoxy-modified RNS-E (particle size 5 nm) as the nano-additives of rapeseed oil, their adsorption behavior in rapeseed oil was studied with a quartz crystal microbalance (QCM-D), and their tribological properties were evaluated with a four-ball friction and wear tester. DNS-2 with a larger particle size can form a high-strength tribo-film on the rubbed surface through shear sintering, thereby reducing the wear scar diameter of the steel ball. DNS-3, RNS-D, and RNS-E with smaller particle sizes can form a viscoelastic adsorption layer on the rubbed steel surface, and their equilibrium adsorption mass thereon increases with the increase of the polarity of the modifiers, which corresponds to the increases in their friction-reducing and anti-wear abilities as well as extreme pressure properties therewith. Particularly, the equilibrium adsorption mass and adsorption rate of RNS-E surface-capped by an epoxy group with the largest polarity are 16 times and 34 times higher than those of DNS-3 surface-capped by methyl. This indicates that encapsulating silica nanoparticles with strongly polar organic species could help to enhance its adsorption on rubbed metal surfaces and improve its tribological properties in rapeseed oil.

Ferritins are spherical iron storage proteins within cells that are composed of a combination of 24 subunits of two types, heavy-chain ferritin (HFn) and light-chain ferritin (LFn). They autoassemble naturally into a spherical hollow nanocage with an outer diameter of 12 nm and an interior cavity that is 8 nm in diameter. In recent years, with the constantly emerging safety issues and the concerns about unfavorable uniformity and indefinite in vivobehavior of traditional nanomedicines, the characteristics of native ferritin nanocages, such as the unique nanocage structure, excellent safety profile, and definite in vivobehavior, make ferritin-based formulations uniquely attractive for nanomedicine development. To date, a variety of cargo molecules, including therapeutic drugs (e.g., cisplatin, carboplatin, paclitaxel, curcumin, atropine, quercetin, gefitinib, daunomycin, epirubicin, doxorubicin, etc.), imaging agents (e.g., fluorescence dyes, radioisotopes, and MRI contrast agents), nucleic acids (e.g., siRNA and miRNA), and metal nanoparticles (e.g., Fe3O4, CeO2, AuPd, CuS, CoPt, FeCo, Ag, etc.) have been loaded into the interior cavity of ferritin nanocages for a broad range of biomedical applications from in vitrobiosensing to targeted delivery of cargo molecules in living systems with the aid of modified targeting ligands either genetically or chemically. We reported that human HFn could selectively deliver a large amount of cargo into tumors in vivoviatransferrin receptor 1 (TfR1)-mediated tumor-cell-specific targeting followed by rapid internalization. By the use of the intrinsic tumor-targeting property and unique nanocage structure of human HFn, a broad variety of cargo-loaded HFn formulations have been developed for biological analysis, imaging diagnosis, and medicine development. In view of the intrinsic tumor-targeting property, unique nanocage structure, lack of immunogenicity, and definite in vivobehavior, human HFn holds promise to promote therapeutic drugs, diagnostic imaging agents, and targeting moieties into multifunctional nanomedicines.

The continuous reduction of clinically available antibiotics has made it imperative to exploit more effective antimicrobial therapies, especially for difficult‐to‐treat Gram‐negative pathogens. Herein, it is shown that the combination of an antimicrobial nanozyme with the clinically compatible basic amino acid L‐arginine affords a potent treatment for infections with Gram‐negative pathogens. In particular, the antimicrobial activity of the antimicrobial nanozyme is dramatically increased by ≈1000‐fold after L‐arginine stimulation. Specifically, the combination therapy enhances bacterial outer and inner membrane permeability and promotes intracellular reactive oxygen species (ROS) generation. Moreover, the metabolomic and transcriptomic results reveal that combination treatment leads to the increased ROS‐mediated damage by inhibiting the tricarboxylic acid cycle and oxidative phosphorylation, thereby inducing an imbalance of the antioxidant and oxidant systems. Importantly, L‐arginine dramatically significantly accelerates the healing of infected wounds in mouse models of multidrug‐resistant peritonitis‐sepsis and skin wound infection. Overall, this work demonstrates a novel synergistic antibacterial strategy by combining the antimicrobial nanozymes with L‐arginine, which substantively facilitates the nanozyme‐mediated killing of pathogens by promoting ROS production. It is reported that L‐arginine exhibits potent synergistic antibacterial activity with nanozymes. The combination therapy leads to increased ROS‐mediated membrane damage by inhibiting the tricarboxylic acid (TCA) cycle, oxidative phosphorylation (OXPHOS), adenosine triphosphate (ATP) synthesis, and the bacterial antioxidant system. The discovery of L‐arginine as a powerful adjunctive agent in combating bacterial infections holds significant implications.

Controlled-release/stable nitrogen (N) fertilizers can improve vegetable yields and achieve lower greenhouse gas emissions, resulting in cost-effective and environmentally friendly vegetable production. However, there has been limited research on long-term fixed-position rotation vegetable fields. The current study involved a five-year field experiment to examine the effects of long-term controlled-release/stable N fertilization on reducing greenhouse gas emissions and increasing lettuce yield. Six distinct treatments were employed for N fertilization: the control treatment with no N application (T0), conventional N application (T1), 80% of conventional N application (T2), 80% of conventional N applied as urea and stable-compound N fertilizer (T3), 80% of conventional N applied as urea and controlled-release N fertilizer (T4), and 80% of conventional N applied as urea and controlled-release stable-compound N fertilizer (T5). The results showed that the T3, T4, and T5 treatments using controlled-release/stable N fertilization emitted about 12.2%–56.7% and less average annual cumulative nitrous oxide (N2O) and 1.31%–10.0% less carbon dioxide (CO2) than T2. Nitrous oxide and carbon dioxide emissions from T4 and T5 were considerably lower than those from T3. No significant seasonal or interannual variability in those types of emissions was observed, indicating the notable stability of controlled-release/stable N fertilization among different years, with non-significant seasonal variation each year. The observed phenomena were attributed to the fluctuations in soil ammonium and nitrate N content. The study’s findings reveal that long-term controlled-release/stable N fertilization resulted in reduced field N loss, which benefits vegetable yields without increasing CO2emissions, highlighting the application potential of this technique for sustainable agricultural production.

We report the size and crystal orientation-dependent thermal behaviors of zinc oxide (ZnO) nanobelts revealed by transmission electron microscopy (TEM) and atomic force microscopy imaging. Direct observation of lattice evolution upon heating unveiled an increase in thermal expansion, yet a decrease of melting point with decreasing ZnO dimensions. Additionally, ZnO nanobelts exhibited orientation dependency on thermal behaviors. High-resolution TEM inspection together with molecular dynamics simulations jointly revealed severe lattice distortion and expansion at and near the nanobelt surface and strong orientation dependency on binding energy. These findings advance our understanding of nano-enabled properties and provide additional design guidelines for developing nanodevices.

We designed and synthesized 131I-labeled dendrimers modified with the LyP-1 peptide as a multifunctional platform for single-photon emission computed tomography (SPECT) imaging, radionuclide therapy, and antimetastasis therapy of cancer. The multifunctional platform was constructed by modifying amine-terminated generation 5 poly(amidoamine) dendrimers with 33.1 LyP-1 peptide and 9.2 3-(4′-hydroxyphenyl)propionic acid-OSu (HPAO), followed by acetylation of the remaining dendrimer terminal amines and radiolabeling with 131I via the HPAO moieties. The LyP-1-modified dendrimers showed favorable cytocompatibility in the studied concentration range of 0.1–10 μM for 24 h and could be labeled by 131I with satisfactory radiochemical purity (>99%) and stability (>90% even at 16 h). The 131I-labeled LyP-1-modified dendrimers were capable of being utilized as a diagnostic probe for SPECT imaging and as a therapeutic agent for radionuclide therapy and antimetastasis of cancer cells in vitro and in a subcutaneous tumor model in vivo. Based on analyses of the tumor microenvironment, the antitumor and antimetastasis effects could be because of the reduced levels of the molecular markers associated with proliferation and metastasis, improved local hypoxia, and increased apoptosis rate. The developed 131I-labeled dendrimeric nanodevice may hold great promise to be used as a nanotheranostic platform for cancer diagnosis and therapy.

Polyimides with intrinsic microporosity have been well developed and explored in the field of gas adsorption and separation. However, most linear polyimides without rigid and distorted segments do not have porous structure owing to the densely packed polymer chains. Two cross-linked polyimides (PEDA-PI-CL and PEQDA-PI-CL) were synthesized from 3,3′-bis(2,3,5,6-tetrafluoro-4-vinylphenoxy)-4,4′-biphenyldiamine (TFVBPA) with 2,5-bis(3,4-dicarboxyphenoxy)-4′-phenyl dianhydride (PEDA) and 2,5-bis(3,4-dicarboxyphenoxy)-4′-phenylethynyl phenyl dianhydride (PEQDA) through polycondensation and thermal cross-linking reactions. Here, the cross-linked structure is utilized to construct microporous polyimides because it can restrict the movement of polymer segments and prevent the polymer chains from dense packing. The micropore size, microporous structure, and CO2adsorption performance can be finely tuned by increasing the cross-linking density from PEDA-PI-CL to PEQDA-PI-CL. The micropore size reduces from 1.06 to 0.54 nm and CO2adsorption increases from 6.32 to 9.88 wt %. Meanwhile, the CO2/N2and CO2/CH4selectivity values of PEQDA-PI-CL at 273 K/1 bar are 76.62 and 12.40, respectively, which is better than many other common microporous polyimides. These results reveal that increasing cross-linking density in cross-linked polyimides is favorable for preparing microporous polyimide networks with smaller pores and higher CO2adsorption selectivity.

Based on BiOBr, an Ag/BiOBr/GO composite catalyst was constructed by doping the noble-metal Ag and the non-metal GO. A Xenon lamp was used to simulate a source of visible light, and Rhodamine B was used as target pollutant. The catalytic activity of the novel catalyst was investigated via degradation experiment. The catalysts were characterized and analyzed by XRD, SEM, TEM, XPS, FT-IR, UV vis-DRS, and EIS. Compared with BiOBr, Ag/BiOBr, and GO/BiOBr, the prepared Ag/BiOBr/GO catalyst (doped with 2.0wt.% GO and 1.5wt.% Ag) exhibited the highest photocatalytic activity, with a RhB degradation rate of up to 98% within 120min. Adding the metal Ag and GO significantly improved the photocatalytic activity of the BiOBr catalyst. This is a result of the Schottky barrier, surface plasmon resonance, and good electrical conductivity of the metal Ag as well as the large specific surface area and excellent electron transport efficiency of the non-metal GO. Their combination promoted the transfer and separation of photo-generated carriers of catalyst, and effectively limited the recombination rate of the photogenerated electron–hole. In a subsequent repeatability experiment, the catalysts still showed good photocatalytic activity and stability after five times of reuse, indicating that the composite catalyst has good stability and reusability value.

Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(bithiophene)] (F8T2) in thermally annealed films exhibits red-shifted absorption spectra, which shows the typical feature of the J-aggregate and is confirmed by computational simulations. By controlling the annealing temperature, the aggregate behavior is explored in detail. It is found that the J-aggregate is formed only when the material is annealed at crystallization and liquid crystal temperatures. The microstructure and morphology of the aggregates show that the J-aggregates have tighter chain packing and a larger ordered domain. This work first demonstrates the J-aggregate behavior of the F8T2 material and establishes the relationship between optical spectra and the packing structure of F8T2.

Three cross-linked porphyrin-based polyimides (PPBPI-H-CR, PPBPI-Mn-CR, and PPBPI-Fe-CR) were synthesized from 5,10,15,20-tetra(4-aminophenyl)porphyrin (TAPP) and 2,5-bis(3,4-dicarboxyphenoxy)-4′-phenylethynyl-biphenyl dianhydride (PEPHQDA) via polymerization and thermal cross-linking reactions. Their chemical structures were confirmed by FTIR and 13C CP/MAS NMR. SEM, XRD, and TEM analyses were used to observe their surface and nature characteristic morphologies as well as pore channels. DSC and TGA were carried out to confirm their cross-linking behaviors and thermal stabilities. PPBPI-H-CR showed the largest specific surface area (733 m2g–1) and the highest CO2uptake (2.26 mmol g–1at 273 K and 1 bar) among the PPBPI-CRs. PPBPI-Mn-CR and PPBPI-Fe-CR compared to PPBPI-H-CR exhibited smaller specific surface areas, more uniform pore sizes around 1.2 nm, and larger isosteric heats of adsorption due to the presence of coordination sites for manganese and iron. PPBPI-CRs exhibited separation factors of CO2/N2(31.48, 35.09, and 45.34) and CO2/CH4(13.17, 9.06, and 12.99).

Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(bithiophene)] (F8T2) is a kind of crystal and liquid-crystal conjugated polymer (CP). In this research, the effect of external electric field (EEF) on F8T2 chain orderness, morphology, and carrier mobility in different condensation processes of annealing at 130 °C (above glass-transition temperature), 200 °C (crystallization temperature), and 280 °C (liquid-crystal temperature) was investigated by UV–vis absorption spectroscopy, photoluminescence spectroscopy, X-ray diffraction, atomic force microscopy, polarizing optical microscopy, transmission electron microscopy (TEM), and current density–voltage (C–V) curves. It was found that EEF could enhance F8T2 chain orderness and manipulate F8T2 chain self-assembly in all the above three types of annealed films. However, the responses of F8T2 chains to EEF were different. After applying EEF, a preferred arrangement along the EEF direction with needle-like crystals was presented in 130 °C annealed films, and ordered nanorod structures were observed in 280 °C annealed films. Meanwhile, subcrystallization with an increased crystallite size of 14.6% was also discovered in the annealed film at 200 °C. As a result, the hole mobilities of these films were improved 127% (130 °C), 367% (200 °C), and 320% (280 °C). The mechanism for both microstructure changes and hole mobility enhancement was revealed. This research sheds a new light to improve carrier mobility by utilizing EEF to control the chain-condensed state structure and film orderness. This also enlightens us to consider the relationship between external forces and chain self-assembly of CPs based on intrinsic properties of CPs and basic theory of condensed matter physics.

Wise selection of host materials and judicious design of electrodes are critical for constructing high-performance energy storage devices. Here we report an unusual cathode configuration for lithium-sulfur (Li-S) batteries employing B4C nanowires (BC-NWs) as a skeleton, porous activated cotton textile (ACT) as a flexible carbon scaffold, and reduced graphene oxide (rGO) as a self-adaptive protective shell. This BC-NWs@ACT/S/rGO cathode achieved superlative sulfur confinement and electrochemical performance with excellent cycling stability (over 1000 cycles at a high current density of 1.5 mA/cm2), an ultralow capacity decay rate (0.056% per cycle) and remarkable capacities at a wide range of discharging rate from 0.1 to 1.5 mA/cm2, demonstrating its potential to achieve high capacity and long cycle life simultaneously in Li-S batteries.

In the past two decades, lithium-ion (Li-ion) batteries have transformed the appearance of the world. Along with the ever-increasing production and usage are the tremendous number of retired batteries, which have created social and environmental issues, making battery recycling an urgent task. Graphene has exhibited outstanding electronic and mechanical properties but it is still difficult to fabricate high-quality graphene with feasible procedures at low cost. Here, a strategy of smartly converting retired Li-ion battery anodes to graphene and graphene oxide is proposed. The graphite powders collected from end-of-life Li-ion batteries exhibited irregular expansion because of the lithium-ion intercalation and deintercalation in the anodegraphite during battery charge/discharge. Such prefabrication process facilitated both chemical and physical exfoliations of the graphite. Comparing with the graphene oxide derived from pristine, untreated graphite, the graphene oxide from anodegraphite exhibited superlative homogeneity and electrochemical properties. The lithiation aided pre-expansion enabled 4 times enhancement of graphene productivity by shear mixing. Furthermore, the graphene fabrication was seamlessly inserted into the currently used battery recycling streamline in which the acid treatment was found to further swell the graphite lattice, pushing up the graphene productivity to 83.7% (10 times higher than that of pristine graphite powders). The findings create new opportunities for capitalizing on waste batteries to produce high-quality graphene and its derivatives.

A novel approach to exfoliating graphite into graphene using ultrasound coupled with a shear mixer in supercritical CO2is presented in this article. The influence of the ultrasound power and the shearing speed on the exfoliation efficiency was systematically studied, and the optimal processing parameters were achieved. In comparison with either the ultrasound or the shearing method, the coupling approach obtained a higher yield, up to 82.6%, and about 60% of the graphene sheets had fewer than three layers. The electrical conductivity of the film formed by the obtained graphene was up to 1.18 × 106S/m. A synergy exfoliation mechanism was proposed: the ultrasound activated the edges of the graphite, generating the gap between the graphite layers, and the shear mixer peeled off the graphene layer from the gap simultaneously. The coupling approach of ultrasound and the shear mixer enabled the production of the graphene.

In our previous study, as a rheological modifier for flat rheology water-based drilling fluid, binary composite temperature-sensitive SiO2nanohybrid was successfully synthesized and characterized [J. Petrol. Sci. Eng. 219 (2022), 111,096]. The aim of this study was to investigate the flat rheological characteristics of emulsion drilling fluid, a temperature-sensitive amphiphilic ternary composite nanohybrid was prepared viathe copolymerization of temperature sensitive polymer monomers N-isopropylacrylamide (NIPAM) and methylallyl alcohol (MAA) in the presence of nano-silica surface-capped by modifier containing double bond (denoted as SiO2-D). The as-prepared PNM/SiO2-D (PNM refers to polymerized NIPAM and MAA) nanohybrid was characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy and transmission electron microscopy. Findings indicate that PNM/SiO2-D nanohybrid has a three-dimensional network structure and a particle size of 20–30 nm. Rheological properties of PNM/SiO2-D nanohybrid in aqueous solution, water-in-oil (W/O) emulsion system and W/O emulsion drilling fluid system were investigated, respectively. And the results revealed that PNM/SiO2-D nanohybrid as a rheological modifier is more sensitive to temperature in the emulsion with a high water-oil ratio, and significantly increase the viscosity of the emulsion system at elevated temperatures. Furthermore, the W/O emulsion drilling fluid with a water-oil ratio of 4:6 exhibits higher modulus values than the one with a water-ratio of 1:9, due to the better suspending capacity of the former for drill cuttings under static conditions, which could ensure the application of emulsion drilling fluid in drilling process.

On the edge of impending energy and environmental crisis, electrochemical energy storage has rapidly gained momentum. Among all the candidates in the “beyond lithium-ion battery” arena, lithium–sulfur (Li–S) battery has attracted extensive attention due to its ultrahigh theoretical capacity and the abundance of sulfur. However, the development of Li–S battery is hindered by its quick capacity decay and short lifespan because of the insulating nature of sulfur/Li2S and the high solubility of lithium polysulfides. Under this scenario, graphene and its derivatives have been explored to overcome the shortcomings of Li–S batteries. Graphene is mechanically robust, highly flexible, and exceptionally conductive, enabling abundant porosity for high sulfur loading, expeditious electron/ion transfer, and effective polysulfide encapsulation. Graphene oxide (GO), on the other hand, is often attached with various functional groups which are able to chemically bond with polysulfides, rendering GO a strong polysulfide entrapping ability. The graphene/GO enabled physical confinements and chemical interactions can be further enhanced via constructing graphene-sulfur configurations and doping functional groups or heteroatoms. In addition to the intrinsic advantages, graphene and GO are highly compatible with many engineering materials, making graphene-based composite electrodes promising for low-cost, high-performance Li–S batteries. This review article sequentially illustrates the interaction between sulfur/polysulfides and graphene, sulfur infiltration methods, sulfur/graphene configurations, applications of graphene and its derivatives in Li–S batteries, and presents state of the art and future outlook.

Nature’s multiscale reinforcing mechanisms in fabricating composite armors, such as seashells, provide lessons for engineering materials design and manufacturing. However, it is still a challenge to simultaneously add both micro- and nanoreinforcements in a matrix material since nano-fillers tend to agglomerate, decreasing their reinforcing effects. In this study, we report a new type of micro/nano hybrid filler, synthesized by an unconventional cotton aided method, which has B4C microplatelet as the core and radially aligned B4C nanowires as the shell. To enhance the bonding between the B4C fillers and epoxy, the B4C micro/nano-fillers were coated with a layer of polyaniline (PANI). With a low concentration of the PANI functionalized B4C micro/nano-fillers (1 wt %), this B4C/epoxy composite exhibited an exceptional combination of mechanical properties in terms of elastic modulus (∼3.47 GPa), toughness (2026.3 kJ/m3), and fracture strain (>3.6%). An analytical mechanics model was established to show that such multiscale reinforcement design remarkably enhanced the load carrying efficiency of the B4C fillers, leading to the overall improved mechanical performance of the composites. This new design concept opens up a new path for developing lightweight, yet high-strength and tough materials with multiscale reinforcing configurations.

Rechargeable sodium-ion batteries have drawn increasing attention as candidates for the post lithium-ion batteries in large-scale energy storage systems. Layered oxides are the most promising cathode materials and their pure phases (e.g., P2, O3) have been widely investigated. Here we report a series of cathode materials with O3/P2 hybrid phase for sodium-ion batteries, which possesses advantages of both P2 and O3 structures. The designed material, Na0.78Ni0.2Fe0.38Mn0.42O2, can deliver a capacity of 86 mAh g–1with great rate capability and cycling performance. 66% capacity is still maintained when the current rate reaches as high as 10C, and the capacity retention is 90% after 1500 cycles. Moreover, in situXRD was performed to examine the structure change during electrochemical testing in different voltage ranges, and the results demonstrate 4 V as the optimized upper voltage limit, with which smaller polarization, better structural stability, and better cycling performance are achieved. The results obtained here provide new insights in designing cathode materials with optimal structure and improved performance for sodium-ion batteries.

Microplastics (MPs) and cadmium (Cd) in the soil have serious negative impacts on plant growth. As a bioremediator, Trichoderma viridemay modulate the impacts of MPs or/and Cd on plant growth and heavy metal uptake. In this study, T. virideF7 (F7) was used to treat Cd-contaminated soil with or without polylactic acid MPs (PLA-MPs) to investigate its effects on peanut growth, Cd uptake efficiency, and soil properties. The results showed that F7 increased the soil pH, dissolved organic carbon (DOC), cation exchange capacity (CEC), microbial nitrogen (MBN), and microbial carbon (MBC), which resulted in a 2.10–19.83% increase in peanut biomass and mitigated the negative effects of PLA and Cd on peanut growth. F7 reduced the soil effective-state Cd and plant Cd content by 16.68–34.20% and 5.37–25.84%, respectively. Regression path analysis showed that F7 could improve peanut performance by altering soil properties and reducing peanut Cd concentrations in PLA-MP- and Cd-contaminated soils. Soil fungal community analysis indicated that the microbial community was altered via F7 inoculation, which antagonized Fusarium and promoted peanut growth. This study reveals the mechanism of F7 in mitigating Cd contamination in soil in the presence of MPs, which provides new ideas for managing complex contaminated soil with MP–heavy metals and improving soil health.

The film quality of organometallic halide perovskite is very crucial to the performance of planar heterojunction solar cells. Previous methods have generally required a long-time and complex process to control the crystal growth for obtaining a compact and smooth perovskite film. Here, we demonstrate a novel method of growing the high-quality films via a simple and rapid process. Organic cations are used as additives in the solution of CH3NH3PbI3(MAPbI3), which plays a key role in the film-forming process. These organic cations can enhance the film-forming ability and do not lead to a residue in the film end-product. On the basis of these characteristics, highly efficient perovskite solar cells with a simple planar heterojunction structure were achieved. Because the additives can simplify and accelerate the fabrication process and have no chance to induce any negative effect on the device, they will have a large potential in the production of various high-quality perovskite films and low-cost, large-scale, and high-performance devices.

A generally accepted method for predicting the bioavailability and transfer of cadmium (Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films (DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass (Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT (CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt (Na2EDTA)– and acetic acid (HOAc)–extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perennewas negatively influenced by pH and positively influenced by organic matter (OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA– and HOAc–extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were pH and OM dependent. For CE, the relationship was pH independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.

Spherical MnCoOxand MnCoOx-multi-walled carbon nanotubes (MnCoOx-MWCNTs) were synthesized by hydrothermal method, and applied as electrode materials for supercapacitors. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and other electrochemical test methods are used to screen the properties of MnCoOxwith different Co/Mn molar ratios and MnCoOx-MWCNTs with different MWCNTs qualities. The performance comparisons show that when the molar ratio of Co/Mn was 1:1, the discharge capacitance of as-prepared MnCoOx-MWCNTs composite containing 0.1 g MWCNTs is as high as 930.00 F g−1at the current density of 1.0 A g−1. The retention rate of specific capacitance of optimal MnCoOx-MWCNTs remains 88.2% after 5000 cycles at the current density of 8.0 A g−1. Therefore, MnCoOx-MWCNTs composite as electrode material has broad development prospects.

Kulakova and Kulakov (2012) have presented the generalised net present value (GNPV) method to evaluate non-conventional projects. They have illustrated the method with three examples: a project of 2-year life with multiple internal rate of returns (IRRs), a project of 2-year life without IRR and a project of 3-year life with a unique real-valued IRR, which is not the rate of return. The purpose of the present study was to test the validity and feasibility of the GNPV method in evaluating other non-conventional projects with a longer life. The method was used to evaluate five scenarios: a project of 5-year life with multiple IRRs; a project of 7-year life with multiple IRRs, which were not the rates of return; a project of 10-year life with a positive and a negative IRR meaning the positive value was the unique IRR; a project of 7-year life with a salvage value and a unique IRR; and a staged expansion project of 10-year life with a unique IRR. It was concluded that the GNPV method worked in all the five cases considered. Advantages of the GNPV method were noticed in agreement with Kulakova and Kulakov (2012) that (i) the minimum attractive rate of return (MARR) was not required to find a solution; (ii) the internal (financing) rate may be different from the external (reinvestment) rate; and (iii) internal and external rates are not necessarily required for solution, but are required for evaluation of the projects. One disadvantage was observed that the computational work in some cases might be overwhelming.

Two nanostructured electrodes were fabricated and used to construct flexible high performance supercapacitors. Hierarchical NiCo2O4nanostructures (with airy organdy NiCo2O4nanosheets on vertical NiCo2O4nanoarrays) were grown on flexible carbon cloth by a facile template-free method while three dimensional (3D) porous graphene papers (PGP) with scaffold-like microstructure were fabricated by freeze-drying. The hierarchical NiCo2O4/carbon cloth (NiCo2O4/CC) and PGP electrodes achieved the maximum specific capacitance of 1768 (based on the mass of NiCo2O4) and 151Fg−1, respectively. The NiCo2O4/CC (as the positive electrode), PGP (as the negative electrode), and PVA–LiOH gel (as both the solid state electrolyte and separator) were assembled into flexible all-solid-state (NiCo2O4/CC//PGP) asymmetric supercapacitor with an exceptional combination of electrochemical properties in terms of working potential (1.8V), maxmum energy density (60.9Whkg−1), maxmium power density (11.36kWkg−1), and cycling stability (96.8% capacitance retention ratio over 5000 cycles under mechanical bending).

Photoacoustic tomography (PAT) is a hybrid imaging modality that takes advantage of high optical contrast brought by optical imaging and high spatial resolution brought by ultrasound imaging. However, the quantification in photoacoustic imaging is challenging. Multiple optical illumination approach has proven to achieve uncoupling of diffusion and absorption effects. In this paper, this protocol is adopted and synthetic photoacoustic data, blurred with some noise, were generated. The influence of the distribution of optical sources and transducers on the reconstruction of the absorption and diffusion coefficients maps is studied. Specific situations with limited view angles were examined. The results show multiple illuminations with a wide field improve the reconstructions.

In order to ensure the security of cloud storage, on the basis of the analysis of cloud storage security requirements, this paper puts forward a kind of hidden mapping hyper-combined public key management scheme based on the hyperelliptic curve crypto system, which is applicable to the distributed cloud storage. A series of operation processes of the key management are elaborated, including key distribution, key updating and key agreement, etc. Analysis shows that the scheme can solve the problem of large-scale key management and storage issues in cloud storage effectively. The scheme feathers high efficiency and good scalability. It is able to resist collusion attack and ensure safe and reliable service provided by the cloud storage system.

Due to its characteristics distribution and virtualization, cloud storage also brings new security problems. User's data is stored in the cloud, which separated the ownership from management. How to ensure the security of cloud data, how to increase data availability and how to improve user privacy perception are the key issues of cloud storage research, especially when the cloud service provider is not completely trusted. In this paper, a cloud storage ciphertext retrieval scheme based on AES and homomorphic encryption is presented. This ciphertext retrieval scheme will not only conceal the user retrieval information, but also prevent the cloud from obtaining user access pattern such as read-write mode, and access frequency, thereby ensuring the safety of the ciphertext retrieval and user privacy. The results of simulation analysis show that the performance of this ciphertext retrieval scheme requires less overhead than other schemes on the same security level.

Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality. Different maize varieties show significant differences in metabolite content. Two kinds of waxy maize parental materials, S181 and 49B, created by the Chongqing Academy of Agricultural Sciences, are widely grown in China. S181 shows higher starch and sugar contents than 49B. This study generated metabolic profiles to assess the differences between the two varieties. A total of 674 metabolites that were significantly differentially expressed between the two varieties were identified by gas chromatography and untargeted metabolomics technology. These metabolites were associated with 21 categories, including antioxidant metabolites. Moreover, 6415 differentially expressed genes (DEGs) were identified by RNA-seq. Interestingly, these DEGs comprised starch and sugar synthesis pathway genes and 72 different transcription factor families. Among these, six families that were reported to play an essential role in plant antioxidant action accounted for 39.2% of the transcription factor families. Using the Kyoto Encyclopedia of Genes and Genomes (KEGG) classification, the DEGs were mainly involved in amino acid biosynthesis, glycolysis/glucose metabolism, and the synthetic and metabolic pathways of antioxidant active substances. Furthermore, the correlation analysis of transcriptome and metabolomics identified five key transcription factors (ZmbHLH172, ZmNAC44, ZmNAC-like18, ZmS1FA2, ZmERF172), one ubiquitin ligase gene (ZmE2 5A) and one sucrose synthase gene (ZmSS1). They likely contribute to the quality traits of waxy corn through involvement in the metabolic regulatory network of antioxidant substances. Thus, our results provide new insights into maize quality-related antioxidant metabolite networks and have potential applications for waxy corn breeding.

The selection of the type of the structured beam is great importance in the study of optical and first-order rainbow scattering by a particle. The Airy light-sheet is a specific type of limited-diffracting beam (in 2D), which has been used in investigations related to radiation forces and torque. Equally important and of practical significance is the study of the electromagnetic/optical resonance and first-order rainbow scattering by a dielectric sphere. The purpose of this paper is to calculate the electromagnetic resonance scattering, energy efficiencies and far-field scattered intensity of a lossless homogeneous dielectric spherical particle of arbitrary size, illuminated by a linearly-polarized non-diffracting electromagnetic Airy light-sheet. A rigorous parametric study is undertaken here to investigate the effect of varying the light-sheet parameters γ, kw0, and its polarization state as well as the size parameter kaof the lossless dielectric sphere on the scattering efficiencies and intensity. The analysis is extended to examine the first-order rainbow scattering phenomenon in the context of Airy light-sheets with different polarizations. Numerical results show that kw0, γ, kaand the state of polarization affect the amplitude and scattering directivity patterns of the efficiencies and intensity. Rainbow scattering arises along the polar scattering angle θ=143°, and is minimally influenced by the different values of the parameters kw0, γ, polarization, and ka. The results are of some practical significance in optical resonance scattering and related applications in optical tweezers, super-resolution imaging, particle characterization, and the measurement of temperature, velocity and size of a liquid jet to name a few applications.