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The effect of boron (B) on stress corrosion resistance of S31254 in the presence of residual stresses has been studied. The microstructure and corrosion resistance of S31254 containing B at different levels of cold deformation are analyzed in this study. In the results, it is shown that B favors the improvement of deformation uniformity of S31254. The grain boundary (GB) and slip bands have better corrosion resistance at 5% deformation, and the overall corrosion resistance is better than that of the undeformed state, with smaller passivation current density and narrower width of GB corrosion grooves, especially for the 40B samples. At 30% deformation, the overall corrosion resistance of 40B S31254 is better than 0B due to improved deformation uniformity. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is the prevailing raw material for fused deposition modeling (FDM) 3D printing filaments, offering benefits such as a low printing temperature, minimal shrinkage, and biodegradability. However, this material has challenges such as poor toughness, low heat deflection temperature, susceptibility to moisture‐induced thermal degradation, and high costs. This study addressed these concerns by incorporating natural bamboo fiber (BF) into PLA, elevating heat the deflection temperature and lowering the material costs. Additionally, a synthesized branched structure compatibilizer, in the form of epoxidized soybean oil‐branched cardanol ether (ESOn‐ECD), enhanced the toughness of PLA, the bonding strength between PLA and the BF surface, and the flowability of high‐fiber composites during processing and printing. The mechanical, thermal, and rheological properties were assessed, demonstrating the promising processing performance of PLA/BF/ESO3‐ECD. The fully biobased composite exhibits strength, toughness, good processability, excellent 3D printability, and durability, implying substantial potential in FDM 3D filament production. Highlights: Bio‐based PLA/bamboo fiber/ESO3‐ECD FDM 3D printing filaments were developed.The excellent nucleation ability of the bamboo fibers enhances the crystallization rate and crystallinity of PLA.The epoxy values and branching degree of ESOn‐ECD are crucial for its effective modification. [ABSTRACT FROM AUTHOR]

Aiming to address the Mo volatilization problem of super-austenitic stainless steel at high temperature, the S31254 steel containing B and rare earth element Y with high oxidation resistance was designed. It was observed that a synergy of B + Y can promote the formation of the dense Cr2O3 layer at 1050 and 1100 °C, making MoO3 layer formation difficult. While the oxide layers of the 0B sample from top to bottom were divided into four layers: Fe-rich oxide layer, MoO3 layer, Cr–Mn–Ni spinel oxide layer, and Cr2O3 layer (loose and porous), thus the undense Cr2O3 layer in the 0B sample can hardly inhibit MoO3 volatilization, especially at 1100 °C. In addition, the synergistic effect of B and Y on the diffusion of Cr to the surface was calculated using first-principles calculations. The results demonstrated that both the addition of B and Y can enhance Cr diffusion to the surface, while Y can specifically promote the combination of Cr and O. Consequently, the combined presence of B and Y exhibits a more favorable synergy for improving the density of the Cr2O3 layer, effectively inhibiting MoO3 formation and volatilization, thereby enhancing the oxidation resistance of S31254. [ABSTRACT FROM AUTHOR]

Background: Chimeric antigen receptor natural killer (CAR-NK) cells represent a promising advancement in CAR cell therapy, addressing limitations observed in CAR-T cell therapy. However, our prior study revealed challenges in CAR-NK cells targeting CD19 antigens, as they failed to eliminate CD19+ Raji cells in NSG tumor-bearing mice, noting down-regulation or loss of CD19 antigen expression in some Raji cells. In response, this study aims to enhance CD19 CAR-NK cell efficacy and mitigate the risk of tumor recurrence due to target antigen escape by developing CD19 and CD20 (CD19/CD20) dual-targeted CAR-NK cells. Methods: Initially, mRNA encoding anti-CD19 CARs (FMC63 scFv-CD8α-4-1BB-CD3ζ) and anti-CD20 CARs (LEU16 scFv-CD8α-4-1BB-CD3ζ) was constructed via in vitro transcription. Subsequently, CD19/CD20 dual-targeted CAR-NK cells were generated through simultaneous electrotransfection of CD19/CD20 CAR mRNA into umbilical cord blood-derived NK cells (UCB-NK). Results: Following co-electroporation, the percentage of dual-CAR expression on NK cells was 86.4% ± 1.83%, as determined by flow cytometry. CAR expression was detectable at 8 h post-electric transfer, peaked at 24 h, and remained detectable at 96 h. CD19/CD20 dual-targeted CAR-NK cells exhibited increased specific cytotoxicity against acute lymphoblastic leukemia (ALL) cell lines (BALL-1: CD19+CD20+, REH: CD19+CD20−, Jurkat: CD19−CD20−) compared to UCB-NK, CD19 CAR-NK, and CD20 CAR-NK cells. Moreover, CD19/CD20 dual-targeted CAR-NK cells released elevated levels of perforin, IFN-γ, and IL-15. Multiple activation markers such as CD69 and cytotoxic substances were highly expressed. Conclusions: The creation of CD19/CD20 dual-targeted CAR-NK cells addressed the risk of tumor escape due to antigen heterogeneity in ALL, offering efficient and safe 'off-the-shelf' cell products. These cells demonstrate efficacy in targeting CD20 and/or CD19 antigens in ALL, laying an experimental foundation for their application in ALL treatment. [ABSTRACT FROM AUTHOR]

Ni was selected as a transition layer and sublayer in the diamondlike carbon-based multilayered film with varied bilayer periods (from 228 to 970 nm) prepared by magnetron sputtering. The reaction between Ni- and C-containing particles was discussed, and the influences of bilayer periods on the structure and morphology, accompanied with the frictional behaviors at different loading forces (2 and 5 N), as well as the field emission properties were investigated. The results showed that Ni grew in the (111) plane, and there was no Ni–C bond or graphene formed in the film because of the relatively lower energy during deposition. Moreover, the content of sp2C in the film, the hardness, and the field emission performance exhibited an initial increase followed by a subsequent decrease with increasing bilayer periods. However, the frictional coefficient decreased owing to more graphitization with an increase of the applied load. Particularly noteworthy was that the film possessed a bilayer period of 710 nm, displayed a compact structure with a smaller grain size, and showed reduced sp2C content in the role of Ni. This resulted in sustained lower surface roughness, heightened hardness, decreased coefficient of friction, and a smaller opening electric field. [ABSTRACT FROM AUTHOR]

In order to study the influence of long-term water action on the behavior characteristics of steel slag aggregate-asphalt interface and the related mechanism, atomic force microscope, X-ray diffraction, scanning electron microscope, immersion Marshall test, rutting test and so on were used to analyze from macro and micro perspectives. The results show that long-term water erosion changes the surface chemical properties of steel slag, making the surface roughness, surface area and adhesion strength of the steel slag increase. Compared with limestone asphalt mixture, the residual stability and dynamic stability of steel slag asphalt mixture have a growth potential, but the swelling of hot-sealed steel slag and cold-sealed steel slag is different. The swelling amount of cold-sealed steel slag asphalt mixture is greater than that of hot-sealed steel slag asphalt mixture, which should be treated differently in the application process. The slow digestion rate of f-CaO in cold-sealed steel slag aggregate causes the volume expansion of the specimen in the late stage, aggravates the generation of microcracks on the surface of the specimen, and results in the poor freeze-thaw splitting strength of cold-sealed steel slag asphalt mixture in the late stage. [ABSTRACT FROM AUTHOR]

Plasticizers are widely used in poly(vinyl chloride) (PVC), polylactic acid (PLA), thermoplastic starch (TPS), and other modified powder materials to enhance the flowability, flexibility, and processability of macromolecules. Because of the reprotoxicity of phthalates in animals and humans, certain phthalates have recently been banned in the United States and Europe. Biobased plasticizers from green biomass–derived renewable resources with low toxicity are expected to be a substitute for phthalates. Among a variety of newly developed biobased monomers, cardanol, and isosorbide are the two most promising materials because of their unique structural features. This review summarizes the research progress of cardanol‐ and isosorbide‐based plasticizers with synergistic effects of plasticization, thermal stabilization, and anti‐migration. By summarizing and analyzing the relationship between molecular structure of plasticizer and plasticizing performance, this review can provide theoretical guidance for future research on the design of isosorbide‐ and cardanol‐based plasticizers. Highlights: Biobased plasticizers with low toxicity are expected to replace certain phthalates.The plasticizing effect of single biobased plasticizer is not good.Biobased plasticizer with synergistic effects is required.There exists the trade‐off effect between the molecular weight and the compatibility.Epoxidized isosorbide ester can be used as a heat stabilizer. [ABSTRACT FROM AUTHOR]

The development of a heat stabilizer with good thermal stability, plasticizing performance, and migration resistance for polyvinyl chloride (PVC) is still a notable challenge. In this work, two bio-based heat stabilizers, epoxidized cardanol oleate (ECD-OA) and epoxidized cardanol myristate (ECD-MA), were designed and synthesized with different lengths of their alkyl chains and different epoxy contents to provide outstanding compatibility with PVC. After confirming the chemical structures of ECD-OA and ECD-MA by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, the thermal stabilizing effects of both epoxidized cardanol esters were compared with those of the traditional CaSt2/ZnSt2 stabilizer and bio-based epoxidized soybean oil. Then, the effects of four different heat stabilizers on the mechanical, thermal, rheological, and optical properties of PVC films were fully studied. The results suggested that the ECD-MA showed the best thermal stability, and the PVC/30DOP/5ECD-MA film did not turn black after 2 h of thermal aging at 200 °C. In addition, the ECD-MA had good compatibility with PVC, and it had a synergistic plasticizing effect, which caused the film to have a high ductility and tensile strength (320.1% and 19.8 MPa, respectively). [ABSTRACT FROM AUTHOR]

Ion transport plays an important role in various biological processes because of the ability of ions to move rapidly in biological ion channel‐confined spaces. For example, rapid proton transport in ATPases is attributed to confined channel spaces and conjugated sites. According to molecular dynamics simulations, the confined spaces and conjugated sites in nanochannels can enhance ion transport. Herein, it is demonstrated that the ATPase‐like structures of sulfonic acid‐modified covalent organic framework nanochannels, which promote the formation of highly ordered and continuous water molecular chains and confined spaces, can support ion (H+, Li+, Na+, and K+) transport rates that are an order of magnitude higher than those of bulk water. The ion transport rates in the nanochannel are superior to those in other artificial channels. Moreover, the selectivity of cations in the nanochannel is evaluated using the diffusion potential with a concentration gradient. The simulations and experimental results demonstrate that confined spaces and conjugated sites are crucial for efficient ion transport in nanochannels modified by sulfonic acid groups as cation conductor materials. [ABSTRACT FROM AUTHOR]

AIM: This study aims to investigate the histopathological and ultrastructural alterations in the lung tissues of rats induced by a single intratracheal administration of bleomycin, with the objective of establishing a reliable model for future applications. METHODS: Six to eight-week-old SD rats were randomly allocated into two groups: the control group and the model group (n=12). Pulmonary fibrosis was induced in the rat models by a single intratracheal instillation of bleomycin (3 mg/kg), while an equivalent volume of saline was administered to the control group. The rats were executed on the 42nd day. Twelve rats remained in the control group, while nine rats remained in the model group. Lung tissue imaging was conducted using CT scans. Lung function tests were performed to assess changes in forced vital capacity (FVC) and dynamic lung compliance (Cdyn). Lung stiffness was determined through Young's modulus testing using a rheometer. The pathological structure of lung tissues was examined using both HE and Masson staining methods. Additionally, transmission electron microscopy was employed to evaluate collagen deposition in lung tissues, alveolar type II epithelial cells, macrophages, and ultrastructural changes of the respiratory membrane. RESULTS: CT scans revealed honeycomb patterns in the lungs of model rats, along with partial bronchiectasis/bronchiectasis. In comparison to the control group, the model group exhibited significantly lower FVC and Cdyn values, while lung stiffness were increased. HE and Masson staining demonstrated that rats in the model group exhibited alveolar structure destruction, alveolar septum thickening, inflammatory cell infiltration, and collagen deposition in alveolar septum. Transmission electron microscopy revealed several abnormalities in the model group: increased collagen fibers in the alveolar septa, misalignment of micro-villi in alveolar type II epithelial cells, wrinkled nuclei with increased heterochromatin, swollen cytoplasmic mitochondria, fractured or haphazardly structured mitochondrion cristaes, and a significant decrease in their number (P<0.05). Furthermore, lamellar bodies were vacuolated and reduced in number (P<0.05), and dilated endoplasmic reticulums with degranulation were observed. There was an increase in alveolar macrophages and interstitial macrophages (P<0.01). The respiratory membrane displayed structural disruptions and an increase in thickness (P<0.01). CONCLUSION: Bleomycin induces decreased lung compliance, alveolar epithelial injury, alveolar septum thickening, collagen deposition, and an increase in interstitial macrophages, ultimately resulting in pulmonary fibrosis in rats. [ABSTRACT FROM AUTHOR]

As one of the important sources of environmental pollution, the sound management of chemicals has entered the international agenda beyond 2020. This article presents the latest trends of sound management of chemicals in the international community, including the negotiation progress on the framework of Strategic Approach to International Chemicals Management (SAICM) and the sound management of chemicals and waste beyond 2020, relevant resolutions adopted by the Fifth United Nations Environment Conference, and preparations for the Science-Policy Panel to contribute further to the sound management of chemicals and waste and to prevent pollution, elabo- rates on the content of the framework text of SAICM beyond 2020 and analyzes the new changes and requirements of the international situation. The sound management of chemicals has become an important chapter in global environmental governance, and China is facing new international situations and challenges. As a new requirement of the Communist Party of China (CPC) Central Committee for deepening the battle against pollution, new pollutants control is the primary task of environmental risk management of toxic and harmful chemicals, which is highly consistent with the international goal of sound management of chemicals. At present, it is necessary to gather joint efforts from both domestic and international sources, actively respond to international challenges, and embark on a new journey in the domestic new pollutants control. [ABSTRACT FROM AUTHOR]

In order to evaluate the anti-reflective cracking performance of high viscosity and high elasticity asphalt mixture (HVHEAM) for ultra-thin wear layer, the improved overlay tester was used to study the effects of different gradation, asphalt content and filler-asphalt ratio on the anti-cracking performance of the HVHEAM. The results show that the anti-reflection crack performance of the dense skeleton type HVHEAM is much higher than those of AC-10 and SMA-10, and the excellent crack resistance of the HVHEAM is mainly reflected in the large initial tensile stress of cracks simultaneously, it has good crack resistance and attenuation performance. Increasing the asphalt contents can improve the anti-crack attenuation performance of the HVHEAM. Increasing the filler-asphalt ratio helps to increase the initial crack resistance of the HVHEAM, but it will reduce the crack-resistance attenuation performance of the mixture, and a good balance between strength and crack-resistance attenuation is achieved when the filler-asphalt ratio is in the range of 0. 8 to 1. 2. In order to improve the anti-crack performance of the ultra-thin wear layer, we recommend that the HVHEAM adopt a dense skeleton structure, the optimal asphalt-to-aggregate ratio range is 7. 3% to 7. 9%, and the optimal filler-asphalt ratio range is 0. 8 to 1. 2. The research results can provide a reference for improving the anti-reflection crack performance of ultra-thin wear layer. [ABSTRACT FROM AUTHOR]

The application of bamboo fibers (BFs) as a reinforcing filler in polylactic acid (PLA) is hindered by their poor compatibility owing to the intrinsic hydrophilia of BFs and the hydrophobicity of PLA. To solve this issue, cardanol (CD) and epoxidized cardanol glycidyl ether (ECGE) were used as compatibilizers to strengthen and toughen PLA/BF bio‐composites, to the best of our knowledge, preparing PLA/BF/CD and PLA/BF/ECGE bio‐composites. The impact strengths of the synthesized bio‐composites increased from 7.75 to 23.75 and 7.75 to 23.95 kJ/m2, respectively, compared with that of a PLA/BF composite without compatibilizer. The investigation of the mechanical properties, crystallization, fractured surface morphology, and solvent stress‐cracking resistance properties revealed that the toughening mechanism of the PLA/BF/CD bio‐composites are mainly based on the plasticization of CD, which results in high impact toughness but low tensile strength. Moreover, the modification with ECGE improves the impact and tensile strengths of the bio‐composite owing to the following factors: (1) the epoxy groups of ECGE generate strong interactions with the BF surface and PLA to form an enhanced interfacial structure; (2) when present at high concentrations, chain extension reaction between ECGE and PLA to increase the molecular chain entanglement of PLA; and (3) upon curing and crosslinking, ECGE forms an entangled network structure that toughens the matrix. [ABSTRACT FROM AUTHOR]

Trisilanolphenyl-polyhedral oligomeric silsesquioxane titanium (Ti-Ph-POSS) was synthesized through the corner-capping reaction, and Ti-Ph-POSS was dispersed in benzoxazine (BZ) to prepare Ti-Ph-POSS/PBZ composite materials. Ti-Ph-POSS could catalyze the ring-opening polymerization (ROP) of BZ and reduce the curing temperature of benzoxazine. In addition, Ti immobilized on the Ti-Ph-POSS cage could form covalent bonds with the N or O atoms on polybenzoxazine, improving the thermal stability of PBZ. The catalytic activity of the Ti-Ph-POSS/BZ mixtures was assessed and identified through 1H nuclear magnetic resonance (1H-NMR) and Fourier-transform infrared (FTIR) analyses, while thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA) were used to determine the thermal properties of the composite. It was found that PBZ exhibited a higher glass transition temperature (Tg) and better thermal stability when Ti-Ph-POSS was added. The curing behavior of the Ti-Ph-POSS/BZ mixtures showed that the initial (Ti) and peak (Tp) curing temperatures sharply decreased as the content of Ti-Ph-POSS and the heating rate increased. The curing kinetics of these Ti-Ph-POSS/BZ systems were analyzed using the Kissinger method, and the morphology of Ti-Ph-POSS/PBZ was determined via scanning electron microscopy (SEM). It was found that the Ti-Ph-POSS particles were well distributed in the composites. When the content exceeded 2 wt%, several Ti-Ph-POSS particles could not react with benzoxazine and were only dispersed within the PBZ matrix, resulting in aggregation of the Ti-Ph-POSS molecules. [ABSTRACT FROM AUTHOR]

In austenitic steels, the co-segregation of C and Cr at grain boundaries can result in the formation of Cr23C6. However, the addition of B to steels can effectively reduce the amount of Cr23C6 formed and inhibit its ripening in experiments, simultaneously transforming it into Cr23(BC)6. Therefore, the effect of B on the co-segregation of C and Cr at the Σ5(210), Σ9(221) and Σ11(113) grain boundaries in austenitic steels was investigated using density functional theory. The results indicate that B, C, and Cr all tend to segregate at the three grain boundaries, with B and C showing a stronger segregation tendency. Furthermore, co-segregation of C and Cr with short distances occurs readily at the Σ5(210), Σ9(221) and Σ11(113) grain boundaries. The presence of B at grain boundaries can impede the segregation of Cr, particularly at the Σ9(221) and Σ11(113) grain boundaries. When B is pre-segregating at the Σ5(210) grain boundary, B, C, and Cr tend to co-segregate at the grain boundary. The grain boundary B hinders the accumulation of Cr near it for most grain boundaries, thereby inhibiting the co-segregation of Cr and C, making it difficult for B, C, and Cr to aggregate at most grain boundaries. This is beneficial for controlling the nucleation of Cr23(BC)6. [ABSTRACT FROM AUTHOR]

Background: 5-Hydroxytryptamine (5-HT) and stem cells marker G-protein-coupled receptor 5 (LGR5) are associate with gastrointestinal inflammation and tumorigenesis. But the relationship between 5-HT and LGR5 is unclear. Objective: To explore the expression and correlation of 5-HT and LGR5 in gastric mucosa of patients with gastritis and gastric cancer (GC). Methods: A total of 41 patients with GC and 98 patients with chronic gastritis were included in this study. The expression of TPH1 mRNA, LGR5 mRNA and β-catenin mRNA in gastric mucosa were explored by Real-time Quantitative polymerase chain reaction (qPCR). 5-HT-positive cells and LGR5-positive cells in gastric mucosa were detected by immunohistochemistry stains. The co-localization of 5-HT and chromogranin A (CgA), 5-HT receptor4 (5-HTR4) and LGR5 were detected by multiplex immunofluorescence. Results: The expression of 5-HT and LGR5 in patients with GC was significantly higher than patients with chronic gastritis (p < 0.05). The positive rate of 5-HT and LGR5 increased sequentially in the patients with non-atrophic gastritis, intestinal metaplasia and GC, which were 18.52%, 35.56% and 75.61% for 5-HT, and 27.78%, 40.91% and 95.12% for LGR5, respectively. The expression of 5-HT and LGR5 was positively correlated in gastritis and GC patients (p < 0.05). Moreover, the expression level of TPH1 mRNA and LGR5 mRNA was also positively correlated in gastritis patients (r = 0.7377, p < 0.001). Besides, 5-HT was partially co-localized with CgA, and 5-HTR4 was co-localized with LGR5 in gastric mucosa. Conclusion: The increase of 5-HT synthesis in gastric mucosa may have an impact on LGR5-positive gastric epithelial stem cells. [ABSTRACT FROM AUTHOR]

The occupation tendencies of Cr, Cu, Mo, Nb, Ni, Ti and V in Fcc-Fe stacking fault containing vacancy were studied by the first principles calculations. The effects of C, N and Nb, Ti co-segregation in the region of vacancy is discussed. The results are as follows: the substitutional elements Cr, Cu, Mo, Ni, Nb, Ti and interstitial elements C, N have no segregation tendency at the stacking fault of Fcc-Fe (111) plane. When the stacking fault contains vacancy, the above elements have the tendency to segregate around the vacancy, and C, N tend to occupy vacancy and their segregation tendency is the stronger than that of substitutional elements. C, N are easily co-segregated with Nb, Ti in the region of vacancy. It is difficult for Mo to aggregate around the carbonitride precipitates, which is conducive to the use of nano-scale carbide and nitride precipitation strengthening in high Mo austenitic steel, and simultaneously improves corrosion resistance. Nb and Ti tend to aggregate around the vacancy where occupied by C, N. [ABSTRACT FROM AUTHOR]

In the present work, the two-phase mixture (HTLc) of hydrotalcite and its oxide were used to improve the barrier properties, UV resistance and antimicrobial activity of Poly(ethylene terephthalate) (PET) for their application in liquid milk packaging. Firstly, CaZnAl-CO3-LDHs with a two-dimensional layered structure were synthesized by hydrothermal method. CaZnAl-CO3-LDHs precursors were characterized by XRD, TEM, ICP and dynamic light scattering. A series of PET/HTLc composite films were then prepared, characterized by XRD, FTIR and SEM, and a possible mechanism of the composite films with hydrotalcite was proposed. Barrier properties to water vapor and oxygen have been studied in PET nanocomposites, as well as their antibacterial efficacy by the colony technique and their mechanical properties after exposure to UV irradiation for 24 h. By the presence of 1.5 wt% HTLc in the PET composite film, the oxygen transmission rate (OTR) was reduced by 95.27%, the water vapor transmission rate was reduced by 72.58% and the inhibition against Staphylococcus aureus and Escherichia coli was 83.19% and 52.75%. Moreover, a simulation of the migration process in dairy products was used to prove the relative safety. This research first proposes a safe technique for fabricating hydrotalcite-based polymer composites with a high gas barrier, UV resistance and effective antibacterial activity. [ABSTRACT FROM AUTHOR]

In order to reduce the segregation of Cr and Mo and inhibit the precipitates, we added a small amount of B and Ce to traditional S31254 steel. Using an air-cooling and low-temperature diffusion treatment, the purpose was to control B and Ce at the grain boundary. The heat-treatment process could prompt co-segregation of B, precipitate-forming elements, and Ce at the grain boundary at 950 °C. After aging at 950 °C for different amounts of time, the diffusion treatment had an obvious inhibitory effect on the precipitates that caused them to become discontinuous, fine, and serrated. The B-containing serrated precipitates were only rich in Mo, while Cr was homogeneously distributed in the probed volume. A uniform distribution of Cr reduced the Cr-depleted zone in the area adjacent to the phase interface. Ce was observed to be segregated at the grain boundary. This showed that Ce could inhibit the formation of precipitates at the grain boundary. The serrated precipitates had an obvious resistance to intergranular corrosion. [ABSTRACT FROM AUTHOR]

Focusing on the serious volatilization of MoO3 in super austenitic stainless steel with a high Mo content, the influence of B on the formation of oxide film and the distribution of Cr and Mo was investigated at 900 °C and 1000 °C. Without the addition of B, Mo tends to diffuse to the surface, forming porous Cr/Mo-rich oxides, causing the volatilization of Mo. The addition of B can inhibit the diffusion of Mo to the surface, facilitate the diffusion of Cr to the surface and combines with O, providing conditions for the nucleation of Cr2O3. A large amount of Cr2O3 accumulated on the surface to form a dense passive film, which inhibited the diffusion of Mo to the surface, reduced the loss of Mo, and formed Mo/Cr-rich precipitates at grain boundaries that are close to the surface. However, it was difficult to form Mo-rich precipitates at the grain boundaries of a sample without B, which aggravated the volatilization of Mo from grain boundary to surface. Therefore, the addition of B can improve the oxidation resistance of 254SMO and inhibit the volatilization of Mo. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC) is a widely used plastics in different industries. It is an intrinsically hard and brittle polymer and requires the use of plasticizers to improve the processability. Commonly used phthalate‐based plasticizers have serious toxicity issues and we present alternatives based on epoxidized soybean oil (ESO) and epoxidized cardanol esters (ECEs). ECEs are synthesized from cardanol and three fatty acids (oleic, ricinoleic, and myristic) using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) as a coupling agent. Their structure and purity are confirmed by Fourier transform infrared spectroscopy (FTIR) and Nuclear magnetic resonance. Moreover, plasticized PVC films are prepared using a solvent‐free method. The replacement of 10 phr of ESO with 5 phr of ECE improves the plasticizing power due to the co‐solvency effect. Mechanical properties and thermal stability of plasticized PVC films are correlated with the chain length and the number of epoxy groups in ECE. The best plasticizing effect is observed for epoxidized cardanol‐myristate (ECD‐MA). ECD‐MA as a shorter‐chain secondary plasticizer is more compatible with ESO and allows higher conformational mobility of PVC chains. PVC/30ESO/5ECD‐MA polymer exhibits an exceptionally high initial thermal decomposition temperature (314.4°C) while preserving moderate ductility and tensile strength (263.4% and 23.3 MPa). Overall, this study highlights the potential applicability of ECD‐MA in combination with ESO as a sustainable, bio‐based plasticizer and heat stabilizer for flexible PVC products. [ABSTRACT FROM AUTHOR]

The occurrence of forest fires can impact vegetation in the ecosystem, property, and human health, but also indirectly affect the climate. JULES-INFERNO is a global land surface model, which simulates vegetation, soils, and fire occurrence driven by environmental factors. However, this model incurs substantial computational costs due to the high data dimensionality and the complexity of differential equations. Deep learning-based digital twins have an advantage in handling large amounts of data. They can reduce the computational cost of subsequent predictive models by extracting data features through Reduced Order Modelling (ROM) and then compressing the data to a low-dimensional latent space. This study proposes a JULES-INFERNO-based digital twin fire model using ROM techniques and deep learning prediction networks to improve the efficiency of global wildfire predictions. The iterative prediction implemented in the proposed model can use current-year data to predict fires in subsequent years. To avoid the accumulation of errors from the iterative prediction, Latent data Assimilation (LA) is applied to the prediction process. LA manages to efficiently adjust the prediction results to ensure the stability and sustainability of the prediction. Numerical results show that the proposed model can effectively encode the original data and achieve accurate surrogate predictions. Furthermore, the application of LA can also effectively adjust the bias of the prediction results. The proposed digital twin also runs 500 times faster for online predictions than the original JULES-INFERNO model without requiring High-Performance Computing (HPC) clusters. The implementation code of this study and the developed models are available at https://github.com/DL-WG/Digital-twin-LA-global-wildfire. [ABSTRACT FROM AUTHOR]

To overcome the migration of epoxidized soybean oil (ESO) used as a poly(vinyl chloride) (PVC) plasticizer, ESO‐branched cardanol (CD) ethers (ESO‐CDn) are designed and synthesized in this work. The incorporation of the benzene ring and the C15 straight chain of CD provided excellent plasticizing efficiency, and the increase in the molecular weight by branching CD with ESO enhanced the migration resistance of the plasticizer. In this work, two different methods are adopted to prepare PVC/ESO/CD and PVC/ESO‐CDn, namely the one‐step method (dynamic vulcanization of ESO, CD, and PVC) and the two‐step method (synthesis of ESO‐CD and then mixing it with PVC). The first method is convenient, while it is also uncontrollable, leading to an incomplete reaction between ESO and CD. The second method offers a controllable reaction between ESO and CD. The chemical structure of ESO‐CDn is fully characterized. Furthermore, the thermal, mechanical, rheology, and migration resistance properties of PVC/ESO/CD and PVC/ESO‐CDn are compared. The relationship between the molecular structure and plasticizer performance is investigated, and the plasticization mechanism is proposed. The tensile and thermal properties indicate that PVC/35ESO‐CD10 offered a superior anti‐thermal aging performance due to the excellent plasticizing and migration resistance effects of ESO‐CD10. [ABSTRACT FROM AUTHOR]

The gel strength and thermal stability of fish gelatin are poorer than mammal gelatin. It's very important to improve the thermal stability which can sustain autoclave sterilization so as to expand the application of fish gelatin. In this study, 10% (w/v) tilapia skin gelatin sols with or without 1% (w/v) low acyl gellan gum were sterilized at 121°C before gelation, and the effects of autoclave sterilization on the textural properties and gel structures were investigated. The results showed that autoclave sterilization decreased the hardness (from 661.8 g to 505 g) and chewiness (from 27.44 mJ to 20.33 mJ) of the gels, which were raised more than four times by gellan gum. The gel point and melting point were increased from 16.7°C and 24.3°C to 40°C and 57°C respectively by gellan gum, both of which could sustain autoclave sterilization. Autoclave sterilization significantly decreased the relative intensity of the secondary structures and increased the interaction between proteins and water. The polypeptide chains in fish gelatin formed spherical aggregates and further formed a spatial network structure, which was destroyed by autoclave sterilization. Gellan gum prevented the damage by forming a continuous phase of a tight network that could sustain autoclave sterilization. So gellan gum strengthened the gelatin network and further increased the gel strength and gel point of the mixed gel. Novelty impact statement: The gel point and melting point of tilapia skin gelatin were lower than room temperature, which limited its application.Gellan gum significantly improved the gel properties and thermal stability of tilapia skin gelatin, both of which could sustain autoclave sterilization.Gellan gum formed a continuous phase of a tight network in the mixed gel, which strengthened the gel structures and would not be damaged by autoclave sterilization. [ABSTRACT FROM AUTHOR]

Brittleness of poly(lactic acid) (PLA), a biocompatible and biodegradable polymer obtained from renewable and natural sources, hinders its widespread applications. This study provides a convenient and economical way to enhance the toughness of PLA by using hydroxyl terminated polybutadiene (HTPB) liquid rubber to modify PLA. Four types of HTPB with varied hydroxyl values and viscosities were used to prepare PLA/HTPB blends. The effects of HTPB content on the mechanical characteristics, phase structure, thermal and crystalline properties of the toughened blends were systematically investigated. For PLA/HTPB2‐5%, the elongation at break and impact strength was 87% and 58 kJ/m2, respectively, which was 12.8 and 3.5 times that of neat PLA. Due to the relatively lower hydroxyl value and suitable viscosity of HTPB2, PLA/HTPB2‐5% exhibited the best impact toughness and had the highest impact strength. When the content of HTPB exceeded 5%, the mechanical properties of PLA/HTPBs gradually decreased. This could be due to the gradual increase of particle size of the dispersed phase with increasing HTPB content, resulting in serious phase separation between the dispersed phase and continuous phase. The resultant PLA/HTPB2 composites with improved toughness could have potential applications in engineering materials thus enlarging the spectrum of applications for PLA. [ABSTRACT FROM AUTHOR]

S is a common corrosion medium for austenitic stainless steels. The severe intergranular fracture of austenitic stainless steels occurs in sulfur environments. In this paper, the permeation of S at different atomic positions for three symmetric tilt grain boundary types, i.e., Σ5(210), Σ5(310), and Σ9(114) have been computed using first-principles calculations. S has the strongest segregation tendency in the Σ5(210) grain boundary. A high content of S at the grain boundary indicates harm to the grain boundary. Sulfur segregation in the grain boundaries can weaken the strength of the metallic bond. When Mo and Cr are present at the Σ5(210) grain boundary, the sulfur-induced embrittlement is inhibited. With increased S concentration at the grain boundary, the coexistence of Mo and Cr can suppress the intergranular fracture of S on the grain boundary. The reason why high-Mo stainless steel has excellent sulfur-induced intergranular corrosion resistance is explained at the atomic level. [ABSTRACT FROM AUTHOR]

Elastic deformation and gaseous rarefaction effects are of great importance to the static and dynamic characteristics of gas microbearings. Based on the effective viscosity model of Veijola, the flexibility matrix was established by finite element method to calculate the elastic deformation of bearing shell surface, and the modified Reynolds equation considering the influence of effective viscosity and elastic deformation was deduced. The effects of bearing elastic modulus, gas effective viscosity, bearing structural parameters and disturbance frequency on the static and dynamic characteristics were analyzed by solving the modified Reynolds equation, effective viscosity equation and elasticity equations of ultra-thin gas film lubrication. The results indicate that the gaseous rarefaction effect significantly reduces the load carrying capacity of microbearings. The load carrying capacity of microbearing increases with the increase of eccentricity ratio and bearing number. Increasing the flexibility of bearing shell can improve the load carrying capacity and friction coefficient of microbearings, while the bearing capacity and friction coefficient of elastic microbearings considering the effective viscosity of gas are small. Compared with the rigid bearing, the reduction of the elastic modulus of the bearing shell significantly increases the dynamic stiffness coefficient and reduces the direct damping coefficient of the microbearings, while considering the gas effective viscosity effect caused by the rarefaction effect reduces the direct stiffness and increases the direct damping coefficient of the microbearings [ABSTRACT FROM AUTHOR]

Cu2V2O7 is an important material to improve low conductivity of Li4Ti5O12. Herein, Li4Ti5O12/Cu2V2O7 with different Cu2V2O7 ratios is successfully prepared by a liquid phase‐assisted dispersion method. The results show that the electrochemical properties of Li4Ti5O12 are affected by the Cu2V2O7 content incorporated in the composites. Among all obtained samples, Li4Ti5O12/0.05 Cu2V2O7 reveals the best electrochemical performance and capacity retention rate, and its first cycle specific capacity is 246.3/197.2 mAh g−1 when the current density is 30 mA g−1 and it maintains values of 175.8/175 mAh g−1 for 200 cycles between 1.0 and 3.0 V. The resulting Li4Ti5O12/0.05 Cu2V2O7 composite also displays higher capacities at elevated current densities of 120 and 1200 mA g−1, with values always superior to those of the original Li4Ti5O12. The detailed electrode dynamics analysis illustrates that the introduced Cu2V2O7 phase in the composites improves the cycle stability and lithium‐ion transfer rate of Li4Ti5O12. Through in situ X‐ray diffractometry (XRD) test analysis of the Li4Ti5O12/0.05 Cu2V2O7 composite material, it is confirmed that the lithium storage mechanism is improved, where metallic Cu is formed in situ during each charge and discharge reaction process; thereby, the electronic conductivity of the composite material is improved and charge transfer resistance of the bulk material is reduced. [ABSTRACT FROM AUTHOR]

The application of bamboo fibers (BFs) to reinforce the impact strength of polylactic acid (PLA) is attractive because of its low cost and high specific strength. However, the main disadvantages of PLA/BF composites are their low compatibility and poor interfacial adhesion caused by different surface energies. In this work, a bio‐based compatibilizer is used to modify PLA/BF composites with a BF content up to 30 wt%. First, sebacic acid (SA) and epoxidized soybean oil (ESO) are reacted to obtain ESO‐SA oligomers with different branching and crosslinking structures. Next, ESO‐SA is incorporated into a PLA/BF composite through dynamic vulcanization, and fully bio‐based PLA/BF/ESO‐SA ternary composites are prepared. Compared to the PLA/BF composite without ESO‐SA addition, the impact strength of PLA/BF/16ESO‐SA12 increases from 5.8 to 14.55 KJ/m2. The toughening mechanism results confirm that the chemical structure of ESO‐SA is the key indicator of the toughening efficiency. [ABSTRACT FROM AUTHOR]

One of the most used inorganic fillers is calcium carbonate which quite efficiently enhances the mechanical characteristics while simultaneously lower the cost of thermoplastics, particularly for biodegradable polyester. Virtually, all studies so far have focused on the quest for the filling and modification of nano‐sized calcium carbonates. However, the quantity of nano‐sized CaCO3 added in the polymer is usually lower than 10%, owing to its high‐surface energy and high‐surface area and makes powder easier to agglomerate. In this work, we prepared poly(butylene adipate‐co‐terephthalate) (PBAT)/calcium carbonate composite films by extrusion‐blown films with up to 40 wt% micro‐sized CaCO3 content. The influence of particle size (5–12 μm) and modification of the particles (with and without silane coupling agents) on the rheological and mechanical properties was thoroughly investigated. Of all the particle sizes employed in this study, the 5 μm (3000 mesh) particles with 30 wt% content coated with 2 wt% aliphatic silane coupling (CA1) agent was observed to furnish the optimum combination of characteristics. The mechanical properties of P7C3/CA1‐2 film even better than that of neat PBAT film. These results provided a simple approach for PBAT/CaCO3 films manufacture with low‐cost and simultaneously with sound mechanical properties, which can be good candidate for mulching films and packaging applications. [ABSTRACT FROM AUTHOR]

In this work, lignin was used as a heterogeneous nucleating agent to increase polylactic acid (PLA) crystallinity. To enhance the gas barrier performance of PLA/LG composite films, two graft copolymers, polylactide‐graft‐glycidyl methacrylate (PLA‐g‐GMA) and polylactide‐graft‐poly (ethylene glycol) methyl ether methacrylate (PLA‐g‐PEGMA) were successfully synthesized and separately used as compatibilizers to modify PLA/LG composite properties such as interfacial adhesion, crystallinity, and mechanical properties. Since crystallites can act as obstacles to gas diffusion, the higher the crystallinity of the polymer matrix, the better gas barrier performance of the composite film will be. The crystallinity and crystalline structure of the PLA matrix was demonstrated by wide‐angle X‐ray diffraction and differential scanning calorimetry results. Since LG particles can act as efficient heterogeneous crystal nucleating agents, a roughly 50% reduction in oxygen permeability (PO2) was obtained by adding 1 phr LG to the PLA matrix (PLA/1LG). Following addition of 10 phr PLA‐g‐GMA to the PLA/LG composite, PLA/PLA‐g‐GMA/LG composite films showed lower gas barrier properties than PLA/LG composites without added compatibilizer. Moreover, the interfacial adhesion of PLA/LG composites was significantly improved after addition of PLA‐g‐GMA. Therefore, PLA/PLA‐g‐GMA/3LG showed the highest tensile strength, 33% higher than that of neat PLA. Following addition of 10 phr PLA‐g‐PEGMA to the PLA/LG composite, the long liner side chains of PLA‐g‐PEGMA were able to act as nucleating agents for PLA to promote the crystallization of PLA. Accordingly, PLA/PLA‐g‐PEGMA/3LG with 3 phr LG showed a roughly 86% reduction in PO2 when compared with neat PLA film. [ABSTRACT FROM AUTHOR]

Rational design of the microstructure of carbon layers of the core–shell metal particle@graphene heterostructures offers immense potential for overcoming the challenges related to the microwave absorption performance. In this study, a new type of Ni@graphene microwave absorber with a controllable microstructure of graphene shells has been innovatively fabricated through an in situ transformation from a solid carbon precursor. The nonlinear dipole resonance of Ni/graphene interfaces induces an intense dielectric loss capacity, while the natural resonance is beneficial to a high magnetic loss. The composites comprising 30 wt% Ni@graphene particles in paraffin exhibit significantly improved absorption efficiency compared with pure Ni microspheres. Reflection loss (RL) values exceeding −10 dB are observed in the range of 15.28–15.6 GHz with a thickness between 2.0 mm and 5.0 mm, and an optimal RL value of −31.42 dB is obtained at 15.52 GHz with a matching thickness of 4.25 mm. More importantly, the maximum microwave absorption corresponding to the resonance frequency can be tuned by controlling the microstructure of graphene shells rather than changing the thickness of the absorbent. This opens up an effective strategy to synthesize attenuation materials with intrinsic narrowband resonance at microwave frequencies. [ABSTRACT FROM AUTHOR]

Polymers of intrinsic microporosity (PIMs) are a new type of polymer material with unique microporous structure and have been widely applied in gas separation. In recent years, PIMs have also experienced rapid growth in liquid separation and purification; however, so far, no review is reported on the application of PIMs in this field. This paper reports a comprehensive and critical review on the recent research progress of PIMs in the application of liquid separation and purification including membrane separation and adsorption. First, the structural characteristics and synthesis methods of PIMs are briefly described. Subsequently, their applications in membrane separation are described in detail, including pervaporation (removal of organics from water, dehydration of solvents, and separation of organic mixtures), nanofiltration (dye rejection), and adsorption (dyes, organic contaminants, metal ions, oil/water separation, and enantiomeric separation). The effect of material structure and modification on the separation performance is emphasized, and possible new research directions are mentioned. Finally, the application of PIMs in liquid separation and purification is prospected. In conclusion, PIMs exhibit excellent separation efficiency and stable operation characteristics in liquid separation and purification, and they have attractive and broad development prospects. More valuable applications remain to be developed. [ABSTRACT FROM AUTHOR]

Coronary artery disease (CAD) is the most frequent cardiovascular disease, which is induced by the decreased myocardial blood supply. The present study is conducted to understand the mechanisms of CAD. The GSE98583, GSE69587, and GSE71226 datasets from the Gene Expression Omnibus database were obtained. The differentially expressed genes (DEGs) were analyzed by the limma package, then the DEGs appeared in two or three datasets were selected as the coregulated genes using the VENNY tool, followed by enrichment analysis using DAVID tool. Protein‐protein interaction (PPI) network, microRNA‐transcription factor‐target regulatory network, and drug‐gene network were visualized. Finally, quantitative PCR and dual‐luciferase reporter assay were conducted to validate the expression of key genes and the target relationship. There were 221 coregulated genes in GSE98583, GSE69587, and GSE71226. Besides, four pathways and 23 functional terms for co‐upregulated genes, and 11 functional terms for co‐downregulated genes were enriched. The degrees of PPI network nodes matrix metallopeptidase 9 (MMP9), C‐X‐C motif chemokine receptor 1 (CXCR1), toll‐like receptor 6 (TLR6), and myeloperoxidase (MPO) were relatively higher. Moreover, MPO could interact with MMP9, CXCR1, and TLR6 in the PPI network. In the regulatory network, TLR6 and MMP9 separately were targeted by miR‐3960 and v‐rel avian reticuloendotheliosis viral oncogene homolog A (RELA). Additionally, MMP9, CXCR1, and MPO were involved in the drug‐gene network. The expression of MMP9, CXCR1, TLR6, and MPO were significantly upregulated in CAD samples than control, and miR‐3960 could bind to TLR6 to inhibit its expression. CXCR1 and MPO might be involved in the progression of CAD. Besides, miR‐3960 might function in the pathogenesis of CAD through targeting TLR6, and RELA might exert its role in CAD via targeting MMP9. [ABSTRACT FROM AUTHOR]

Aromatic porous polymer networks (PPNs) are promising candidate materials for organic solvent nanofiltration (OSN) membranes, in which molecular-sieving selectivity, high permeability, and chemical/structural stability can be integrated. In this work, aromatic PPN membranes p-PPN, m-PPN and tri-PPN are fabricated by in situ aldol triple condensation cross-linking. These membranes demonstrate high stability, permeability and sharp selectivity in OSN, thanks to the aromatic nature of the backbone, high surface area (up to 1235 m2 g−1), and narrowly distributed pore sizes. They possess a high organic solvent permeability so that a good permeance is achieved despite a thickness of over 100 μm. The molecular weight cut-off and molecular weight retention onset of these membranes are ∼600 g mol−1 and 350 g mol−1, respectively, making it possible to efficiently separate molecules from a complex mixture composed of compounds with only marginally different molecular weights. As a result of the highly stable nature of the aromatic backbones, these PPN membranes show retained structural integrity and OSN performance in the presence of either a strong acid or strong base for over 50 h. The extraordinary stability integrated with excellent permeability and selectivity renders these PPN membranes promising candidates for challenging OSN applications under extreme conditions. [ABSTRACT FROM AUTHOR]

Poly (ethylene terephthalate-butylene adipate) (PBAT) was modified by chain-extension reaction extrusion in a twin-screw extruder using a multi-component epoxy chain extender (ADR), and the effects of the addition amount of ADR on the content of terminal carboxyl groups, relative molecular weight, mechanical properties, crystallinity and color of PBAT were investigated. The results indicated that the terminal carboxyl group content of PBAT was reduced after the chain extension, and its mechanical properties and relative molecular weight were improved. The terminal carboxyl group content of PBAT decreased significantly from 2,3. 3 mol/t to 13. 8 mol/t when 1 wt% of ADR was added, and its relative molecular weight, crystallization temperature, and mechanical properties were also improved. Moreover, the maximum mechanical properties were achieved for PBAT when 1 wt% of ADR was added, and its elongation at break was higher than those of the other samples during the aging process. In addition, the PBAT after chain extension exhibited better aging resistance in view of its chemical structure as well as the relative molecular weight higher than the other samples during the aging process. [ABSTRACT FROM AUTHOR]

Owing to the unique merits benefited from the two‐dimensional (2D) geometry, graphene has been often chosen as an attractive strength enhancer during the design of metal‐graphene structural composites. In spite of the improved mechanical properties with the assistance of graphene, it is still challenging to fit the strength requirements for these metal‐graphene composites in the practical applications. To address this issue, metal‐doping and carbon‐vacancy engineering, in this work, are first proposed to manipulate the dual‐phase interfaces between metal and graphene in order to further strengthen the mechanical properties in metal‐graphene composites based on the first‐principle calculation. It can be concluded that a single‐carbon‐vacancy graphene or a Ti, Mn‐doped metal matrix in metal‐graphene composites delivers the best interfacial binding capability, resulting in an obvious strength increase of over 110% for Cu‐graphene composites. Finally, the deformation mechanisms of metal‐graphene composites are discussed via the evaluation on tensile deformation processes, electron densities, and stacking fault energies. This work offers us an alternative solution for the effective reinforcement on mechanical properties of metal‐graphene composites by manipulating the dual‐phase interfaces using doping or vacancy engineering. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the effect of iron content on the friction and wear performances of Cu–Fe-based friction materials under dry sliding friction and wear test condition. Design/methodology/approach: Cu–Fe-based friction materials with different iron content were prepared by powder metallurgy route. The tribological properties of Cu–Fe-based friction materials against GCr15 steel balls were studied at different applied loads and sliding speeds. Meanwhile, microstructure and phases of Cu–Fe-based friction materials were investigated. Findings: Cu–Fe-based friction materials with different iron content are suitable for specific applied load and sliding speed, respectively. Low iron content Cu–Fe-based friction material is suitable for a high load 60 N and low sliding speed 70 mm/min and high iron content Cu–Fe-based friction material will be more suitable for a high load 60 N and high sliding speed 150 mm/min. The abrasive wear is the main wear mechanism for two kinds of Cu–Fe-based friction materials. Originality/value: The friction and wear properties of Cu–Fe-based friction materials with different iron content were determined at different applied loads and sliding speeds, providing a direction and theoretical basis for the future development of Cu–Fe-based friction materials. [ABSTRACT FROM AUTHOR]

Three bis(phenyl)fluorene-based cardo diamine monomers with different side groups (–CF3, –H, and –CH3) were synthesized and used to synthesize three 6FDA-based polyimides (6FDA-FBPF, 6FDA-BPF, and 6FDA-MBPF). The influence of bis(phenyl)fluorene cardo moiety and different side groups on the glass transition temperature (Tg), thermal stabilities, and chain packing of the synthesized polyimides were systematically studied. The gas permeabilities and selectivities of three bis(phenyl)fluorene-based polyimide membranes were studied and correlated with their fractional free volumes and chain packing conditions. As a result, the obtained polyimides showed promising performance for hydrogen separation. Among the three polyimides, 6FDA-FBPF had the highest gas permeabilities which exhibited H2 permeability of 151.12 Barrer and H2/CH4 selectivity of 62.19. The high gas separation performance of 6FDA-FBPF mainly attributed to the ineffective chain packing via the incorporation of bi(phenyl)fluorene cardo moiety and introduction of bulky CF3 side groups into the polyimide backbones that is favorable to formation hourglass-shaped pores. [ABSTRACT FROM AUTHOR]

Herein, we report an efficient nickel-catalyzed direct cyclization of amines with alcohols for the synthesis of various nitrogen containing heterocycles. These processes employ the sustainable “borrowing hydrogen” strategy and have many advantages, such as earth-abundant metal catalysts, easily available starting materials, wide synthetic versatility and harmless waste emission. [ABSTRACT FROM AUTHOR]

Lithium‐dendrite growth is one of the most challenging problems affecting the safety performance of Li‐ion batteries. Understanding the evolution process of Li‐dendrite growth at the atomic scale is critical for solving this problem. In this paper, the adsorption processes, geometrical configurations, and electronic structures of Li clusters on double‐layered graphene with two types of defects were investigated by first‐principles calculations. It was found that single vacancy (SV) defects tend to promote the nucleation of Li dendrites, and the adsorption energy of Li clusters near the SV defect decreases with increasing number of Li atoms. Meanwhile, the Li atoms accumulated on the surface of SV‐defect graphene with distances between the Li atoms similar to those in bulk metallic Li. However, in the case of double vacancy (DV) defects, the Li atoms could diffuse freely in the direction perpendicular to the graphene sheets through DV defects at the top‐layer graphene, thus hindering nucleation and dendrite growth. Density of states analyses suggested that the Li atoms on SV‐defect graphene transform from the fully ionized state to the metallic state with continuously increasing number, while the ionic properties of the Li atoms remain and even increase on DV‐defect graphene. Our conclusions can help to understand the Li‐graphite interaction from an atomistic point of view and provide theoretical hints for the development of graphite anodes with high charge‐rate properties. The adsorption of lithium clusters on double‐layered graphene structures with single‐ and double‐vacancy defects is simulated by first‐principles calculations. It is shown that single‐vacancy defects promote dendrite nucleation with the interaction energy becoming weaker. However, the Li ions can go through the double‐vacancy defects into the inter‐layer to inhibit dendrite nucleation. [ABSTRACT FROM AUTHOR]

Manganese oxide/reduced graphene oxide (MnO2/rGO) hybrid with layered MnO2 nanosheets grow on rGO surfaces have been prepared for microwave absorbing. The hybrid exhibits significantly enhanced microwave absorption properties compared with rGO and MnO2. A maximum reflection loss value can reach − 26.7 dB at 11.04 GHz with the matching thickness of 2.6 mm, and the effective absorption bandwidths exceeding − 10 dB and − 20 dB are 3.6 GHz and 1.06 GHz, respectively. The enhancement in microwave absorption efficiency of MnO2/rGO hybrid is arose from the synergistic effects between lamellar MnO2 and rGO in its unique three-dimensional (3D) architecture, which leads to strong conduction loss and multiple reflections, and further in favour of appropriate impedance matching ratio and good attenuation ability. These fundamental understandings on the property-structure relationship of as-synthesized MnO2/rGO hybrid will prove an efficient approach to the designing and construction of MnO2-based 3D nanostructures for advanced electromagnetic wave absorbing applications. [ABSTRACT FROM AUTHOR]

Abstract: Polymers with rigid and contorted structures are always preferred for use as gas separation membranes. Owing to the contorted nature of the spiro‐center, the spirobichroman structure is an effective scaffold for impeding polymer chain packing. Two spirobichroman‐based diamines, 6,6′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (FSBC) and 6,6′‐bis(4‐aminophenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (SBC), with or without CF3 side groups are prepared. The two diamines are separately reacted with 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride (DSDA) to obtain four spirobichroman‐based polyimides, denoted as BTDA‐FSBC, BTDA‐SBC, DSDA‐FSBC, and DSDA‐SBC. The different molecular structures among the four monomers are expected to alter the fractional free volume of the corresponding polyimides by impacting chain‐packing conditions, and then controlling the gas transport properties. Chemical structures, thermal and physical properties of the polyimides are fully characterized. Two different methods, molecular dynamics simulation and Bondi's group contribution method are employed to characterize the fractional free volumes (FFVs) of these polyimides. In the end, it is found that FSBC‐based polyimides exhibit relatively higher gas permeability than SBC‐based polyimides. [ABSTRACT FROM AUTHOR]

To improve fuel use and energy-conversion efficiency and reduce the emission of pollutants, oxygenation is now deemed an effective chemical treatment of water in supercritical and ultra-supercritical power plants. Supercritical water with dissolved oxygen significantly enhances the oxidation rate of steels in the main steam pipeline and super-heater header. However, at the atomic scale, the mechanism of metal oxidation in supercritical water containing dissolved oxygen is unknown and has not been investigated by simulation. In this work, the oxidation of iron in supercritical water containing dissolved oxygen is studied by ab initio molecular dynamics and first principles calculations. The results indicate that dissolved oxygen in supercritical water dramatically accelerates the oxidation of iron. With the help of oxygen, the decomposition of water occurs on the iron surface, thereby producing more iron oxides and iron hydroxides. Additionally, hydrogen peroxide (H2O2) forms as an intermediate product, instantaneously decomposing to form iron hydroxides, and this is another reason for the enhancement in the oxidation of steel by supercritical water containing dissolved oxygen. Based on the results from ab initio molecular dynamics, we develop herein typical models of water molecules and oxygen molecules reacting directly on the iron surface and then carry out first-principles calculations. The results show that water decomposes on the iron surface only with the assistance of adjacent oxygen molecules and in the absence of surrounding water molecules. This investigation deepens our understanding of the oxidation mechanism of metal in supercritical water containing dissolved oxygen. The ideas and methods implemented in this work can also be used to study other materials exposed to supercritical water involving oxygen. [ABSTRACT FROM AUTHOR]

High‐temperature initial oxidation behavior at 1000 °C in LDX 2101 oxidized in a closed element is studied. The samples are investigated using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, glow discharge optical emission spectroscopy, and Raman spectra. Results show differences in morphology and development of oxides on the two phases. In the initial stage, the oxide on austenite is granular, whereas that on the ferrite region is homogeneous. However, the entire surface is full of chromium oxide. In the austenite phase, oxide gradually changes from Fe2O3 to Cr2O3. By contrast, oxide transforms from Mn2O3 to Fe2O3 and then to Cr2O3 in the ferrite phase. In addition, manganese enrichment is observed in the entire oxidation process. [ABSTRACT FROM AUTHOR]