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Conductive fillers are critical raw materials for many applications. However, vulnerability to salt spray corrosion remains the biggest problem for silver-plated conductive fillers. Herein, highly conductive silver-plated carbon fiber powders (Ag/pCF) were prepared via catechol/polyamine activation and subsequently formed a tannic acid/metal ion (TA@Me) complex inhibition layer. The electromagnetic interference (EMI) shielding effectiveness of the composite fabricated with original Ag/pCF decreased from 106.4 to 90.4 dB after a 4-cycle salt spray corrosion test, while the composites protected by TA@Me remained unchanged above 110 dB. Further research revealed that TA@Me could effectively block the penetration of Cl–, which is the primary corrosive chemical in a salt fog environment. Considering the high conductivity and the excellent antisalt spray performance, the Ag/pCF protected by the efficient TA@Me inhibition layer via an eco-friendly approach will be a priority alternative for high-performance EMI-shielding applications.

The development of dc–dc converter topologies has been a topic of great interest due to their increasing use in various industrial applications. However, most of the topology-building methods are artificial, which may result in the miss of potentially useful topologies and incur a heavy time cost due to the limitations of human experience. To address the abovementioned issue, this article proposes an automatic search algorithm for finding useful dc–dc converter topologies with two switches, which have broad application prospects in renewable energy generation and dc microgrids. The proposed algorithm is based on the vertex prime degree of the converters, which automatically searches out all available dc–dc converter topologies and avoids generating vast useless isomorphic topologies. As an example, for the S2D1C1L1 type dc–dc converters, which have two switches, one diode, one capacitor, and one inductor, this article founds 40 available S2D1C1L1 type dc–dc converter topologies using the proposed algorithm, including 36 new topologies and 4 existing topologies in the literature. The proposed search algorithm's effectiveness is verified by circuit simulation and experiment. Furthermore, the topology search time is compared among the proposed algorithm, the programmable topology search method using vertex degree classification and the topology search algorithm using permutation and combination. Finally, it is demonstrated that the new algorithm can search out all the available S2D1C1L1 type dc–dc converters in just 11 s, while the existing four topologies were proposed in 2007 and 2020, respectively, which took more than ten years. This article provides a fast and ergodic way for finding dc–dc converter topologies with two switches.

The classical model of concerted evolution states that hundreds to thousands of ribosomal DNA (rDNA) units undergo homogenization, making the multiple copies of the individual units more uniform across the genome than would be expected given mutation frequencies and gene redundancy. While the universality of this over 50-year-old model has been confirmed in a range of organisms, advanced high throughput sequencing techniques have also revealed that rDNA homogenization in many organisms is partial and, in rare cases, even apparently failing. The potential underpinning processes leading to unexpected intragenomic variation have been discussed in a number of studies, but a comprehensive understanding remains to be determined. In this work, we summarize information on variation or polymorphisms in rDNAs across a wide range of taxa amongst animals, fungi, plants, and protists. We discuss the definition and description of concerted evolution and describe whether incomplete concerted evolution of rDNAs predominantly affects coding or non-coding regions of rDNA units and if it leads to the formation of pseudogenes or not. We also discuss the factors contributing to rDNA variation, such as interspecific hybridization, meiotic cycles, rDNA expression status, genome size, and the activity of effector genes involved in genetic recombination, epigenetic modifications, and DNA editing. Finally, we argue that a combination of approaches is needed to target genetic and epigenetic phenomena influencing incomplete concerted evolution, to give a comprehensive understanding of the evolution and functional consequences of intragenomic variation in rDNA.

Organosulfates (OSs) could be potentially important compounds in marine organic aerosols, while their formation in marine atmospheres is far from clear due to a lack of cruise observations. In this work, shipboard atmospheric observations were conducted over the Yellow Sea and Bohai Sea to investigate the abundance and formation of biogenic isoprene/monoterpene-OSs in marine aerosols. The quantified OSs and NOSs accounted for 0.04–6.9% of marine organic aerosols and were 0.07–2.2% of the non-sea-salt (nss) sulfate in terms of sulfur content. Isoprene-related (nitrooxy-)OSs occupied 27–87% of the total quantified OSs, following the abundance order of summer > autumn > spring or winter. This order was driven by the marine phytoplankton biomass and sea surface temperature (SST), which controlled the seawater and atmospheric isoprene concentration levels. Under the severe impacts of anthropogenic pollutants from the East Asia continent in winter, monoterpene nitrooxy-OSs, generated with NOxinvolved in, increased to 34.4 ± 35.5 ng/m3and contributed 68% of the quantified (nitrooxy-)OSs. Our results highlight the notable roles of biogenic OSs in marine organic aerosols over regions with high biological activity and high SST. The formation of biogenic OSs and their roles in altering marine aerosol properties calls for elaboration through cruise observations in different marine environments.

Highly conductive fillers are an essential raw material in the fabrication of conductive composites, paste, ink, adhesive, etc. Still, susceptibility to salt spray erosion remains a serious issue for silver-based fillers. Herein, we first prepared highly conductive silver-plated microspherical silica (Ag/pSiO2) through catechol/polyamine surface functionalization and subsequently formed a self-assembled inhibition layer on the surface of Ag/pSiO2by using (3-mercaptopropyl)trimethoxysilane (KH590) to enhance the salt spray erosion resistance. The results suggested that the self-assembled KH590 greatly improved the salt spray erosion resistance of the Ag/pSiO2. The total shielding effectiveness (SEt) of the composites protected by KH590 was 106 dB after the salt spray erosion, which was even 16 dB higher than that before erosion. In contrast, the SEt of the composites without KH590 decreased significantly from 111 to 76 dB. Further studies revealed that the KH590 inhibitor strongly prevented the penetration of Cl–and subsequently enhanced the salt spray resistance. Considering the facile and effective preparation, this strategy could be applied in large-scale silver-based EMI shielding materials.

Superhydrophobic surfaces present promising potential for improving the mechanical and chemical durability of electromagnetic interference (EMI) shielding materials. However, integrating superhydrophobicity and EMI shielding is still a challenge due to the complex structural design. Herein, superhydrophobic and highly durable fabrics with excellent EMI shielding effectiveness were fabricated. First, the meta-aramid nonwoven fabrics were functionalized by a polydopamine layer. Then, with the assistance of the metal-binding ability of polydopamine, silver nanoparticles were immobilized on the fiber surface by electroless plating. Finally, after the introduction of fluorine-containing agents via a facile dipping method, a superhydrophobic surface was successfully obtained. The as-prepared fabrics showed excellent EMI shielding effectiveness of 111 dB due to superior electrical conductivity (234 S/cm). Moreover, thanks to the low surface energy of fluorine-containing molecules as well as the micro-nanoroughness created by the stacking of silver nanoparticles, the composite fabrics exhibited a large water contact angle of 152° and a low sliding angle of 5°. It was noted that the composite fabrics still maintain superhydrophobicity and high EMI shielding effectiveness (110 dB) even after the acid and alkali corrosion, bending, abrading, and salt fog test, respectively, demonstrating their durability under harsh environments.

As the most outstanding type of organic fiber in terms of the comprehensive performance, polyimide fiber is more conducive to reduce the composites weight than inorganic fibers, such as carbon fiber or glass fiber. A polyimide-fabric-reinforced polyether ether ketone (PEEK) composite was prepared by a hot-press molding process. The melt flow rate of the PEEK resin was measured to reveal its rheological behavior and guide the selection of the molding process parameters of the composite. The tensile properties of the composites were determined. The results revealed that the rheological properties of the resin manifested through the melt viscosity, which was more sensitive to pressure changes than to temperature changes. The tensile properties of the composites were affected by two competitive mechanisms. First, increases of molding temperature and duration time could facilitate the infiltration of the resin into the fiber fabric and improve the internal quality and tensile properties of the composite. Second, an excessively high molding temperature and long duration time could decrease the strength of the polyimide fiber, thereby reducing the tensile properties of the composites.

Fog processing has a significant impact on sulfur chemistry in the atmosphere. This study analyzed three winter fog events in Hong Kong using single‐particle aerosol mass spectrometry (SPAMS) and a Monitor for AeRosols and GAses in ambient air (MARGA). Black carbon (BC)‐related carbonaceous particles with substantial sulfate amounts comprised the largest particle number fraction (56.7%). Sulfate mass concentration decreased during fog due to the cloud's effective scavenging, but fog processing notably promoted sulfate formation at the single‐particle level (average peak area increases of 31.2%). Hydroxymethanesulfonate (HMS), an important S(IV) compound and fog tracer, was identified accounting for up to 12% by particle number fraction. Although pH showed a positive correlation (r= 0.53–0.69) with HMS particles in each fog scenario, a negative overall correlation (r= −0.51) was observed. Further analysis revealed that the higher aerosol acidity (pH 0.65–3.11), promoted Fe dissolution, leading to 49% of HMS particles being mixed with Fe, which potentially facilitated sulfate formation via the Fenton reaction. Additionally, around 40% of HMS‐Fe particles are mixed with oxalate, thereby warranting further attention for their potential to cause more intricate sulfur oxidation processes. This study reveals the initial identification of a high mixed‐state of HMS‐Fe, which could potentially serve as a crucial avenue for the formation of sulfate on individual particulate matter. Considering the persistent augmentation of aerosol acidity in the Asian region, this phenomenon necessitates further investigation and attention. Cloud and fog processes are crucial for atmospheric chemistry and important pathways in sulfate formation. However, current models often underestimate sulfate production in the atmosphere. While several potential pathways have been proposed, the influence of organic compounds on hydroxymethanesulfonate (HMS) formation and its subsequent sulfate generation is yet to be fully explored. This study, utilizing a single‐particle perspective, reveals that higher aerosol acidity in coastal areas can lead to the dissolution of iron (Fe) in coastal aerosols, thereby promoting the formation of HMS‐Fe. Additionally, as a transition metal, Fe has the potential to catalyze the conversion of HMS to sulfates. This finding challenges the prevailing notion that HMS hinders sulfate production by being less susceptible to oxidation by hydrogen peroxide (H2O2) and other radicals. The significance of this process is particularly pronounced in coastal or remote marine atmospheres, where cloud and fog processes exhibit higher aerosol acidity and limited ammonia sources. Furthermore, considering the current global scenario of increased aerosol acidity, the impact of transition metals on sulfate formation in HMS is likely to be more prominent. Consequently, this phenomenon necessitates further investigation and attention.

Smoke aerosols from wildfires play a vital role in marine ecosystems and the ocean carbon cycle. This study analyzed a severe wildfires incident occurred in the Indo‐China Peninsula on 26 March 2019, and assessed its impact on ocean carbon sink. The satellite observations showed that the wildfires covered an area of about 56% of the entire peninsula, burning an area of 1.17 × 106km2. Consequently, the wildfires discharged about 0.43 × 109kg carbon. Moreover, a substantial amount of smoke released by severe wildfires was carried downstream by the wind and reached the western Pacific Ocean within 2 days. These smoke aerosols contribute to the ocean carbon sink through the mechanisms of the biological pump and their own carbon deposition. Model simulation results showed smoke aerosols contribute 6.44 × 104kg black carbon to surface ocean by their own carbon deposition. Moreover, during the period of smoke aerosol's deposition, the flourishing growth of phytoplankton resulted in an increased carbon export of 0.25 ± 0.09 × 109kg carbon (the biological pump mechanism), which represented approximately 57.97% ± 20.30% of the carbon emissions originating from the wildfire‐affected source region. Our research showed a positive impact of large wildfires on the ocean carbon sink, indicating the potential of smoke aerosols to alleviate the climate pressures resulting from carbon dioxide released by wildfires through improving the capacity of ocean carbon sink. Wildfires emit substantial amounts of carbon dioxide into the atmosphere within a short timeframe. The ocean can mitigate the environmental impact of these wildfire events by fixing carbon. As one of the world's fire hotspot and the most significant burning area in the whole of Asia, it is necessary to understand the contribution of smoke aerosols emitted from the Indo‐China Peninsula to the Pacific Ocean carbon sink. We found that the source area of wildfires emitted 0.43 × 109kg of carbon on 26 March 2019, and the smoke aerosols emitted by wildfires were carried by winds to the western Pacific Ocean within two days, and inputted 6.44 × 104kg of black carbon. The increased ocean carbon export during the deposition of the smoke aerosol was 0.25 ± 0.09 × 109kg, which is about half of the carbon emissions caused by wildfires. The results of this study suggest that smoke aerosols can contribute to the oceanic carbon sink, thereby alleviating the pressure on carbon emissions caused by wildfires. A severe fire incident which account for 56% of the land area of the Indo‐China Peninsula has been researchedContribution of smoke aerosols to surface ocean carbon sink is primarily attributed by biological pump rather than carbon self‐depositionThe ocean assimilates around 57.97% ± 20.30% of the carbon emissions released by wildfires A severe fire incident which account for 56% of the land area of the Indo‐China Peninsula has been researched Contribution of smoke aerosols to surface ocean carbon sink is primarily attributed by biological pump rather than carbon self‐deposition The ocean assimilates around 57.97% ± 20.30% of the carbon emissions released by wildfires

The Paleo-Asian Ocean (PAO) had multiple collage systems and closed along multiple sutures. The final timing of the closure of the PAO was closely related to the formation of Pangea. The final timing of closure of the eastern PAO is controversial and may have been from the Middle Permian to the Middle Triassic. This paper presents new zircon U–Pb ages and Hf isotope data for sedimentary and volcanic rocks layer in the Linxi Formation in the Xingmeng Orogenic Belt (XMOB). We also obtained geochemical data for the volcanic rocks layer to constrain the timing and mechanisms of the PAO closure. Detrital zircon U–Pb dating yielded the youngest ages peak of ca. 263 and 260 Ma for two sandstone samples. Combined with the crystallization age of the volcanic rocks layer (254.2 ± 1.3 Ma), this indicates the Linxi Formation was deposited during the Late Permian. Age spectra and Hf isotopic compositions of the detrital zircons from the Linxi Formation suggest that detrital zircons with ages of <1500 Ma were derived from the XMOB, whereas those with ages of 2100–1600 Ma were derived from both the XMOB and the North China Craton (NCC). The detrital zircons with ages of >2400 Ma were derived from the NCC. Geochemical features of the volcanic rocks layer are consistent with eruption in a compressional tectonic setting and derivation by partial melting of the lower crust. Based on our data and the Late Permian history of magmatism and sedimentation, the Linxi Formation was likely deposited in a tectonic setting that transitioned from convergence to collision. Finally, we suggest the PAO closed in a ‘scissor-like’ fashion in the eastern CAOB during the Late Permian, in a setting of tectonic compression.

Silicone elastomers (SRs) are of great scientific and technological importance due to their resistance to low temperatures. However, the glass transition temperature (Tg) of existing SRs is not low enough to satisfy its utilization in the extremely low-temperature environment. Meanwhile, crystallization often occurs at the low-temperature, making it difficult for SRs to maintain their original properties in the extremely low-temperature environment. Here, by combining molecular dynamics (MD) simulation and experiment, a novel low-temperature resistance and crystalline-free SR (Epoxidized-Methyl-Ethyl-Vinyl Silicone Elastomer, also referred to E-MEVQ) is fabricated by random copolymerization of three different siloxane repeat units (dimethyl-siloxane, diethyl-siloxane and methyl-epoxy-siloxane). We showed that the Tgof E-MEVQ computed from MD simulations using three different methods (specific volume, nonbond potential energy and conformational transition versus temperature) agrees well with that of the as-synthesized E-MEVQ determined by Differential Scanning Calorimetry. The Tgis approximately −130 °C, much lower than that of Polydimethylsiloxane (PDMS), and the E-MEVQ is in the amorphous state without any crystallization. This novel silicone elastomer is expected to be widely applied in the field of smart devices, sensors, and medical equipment under extreme situations. Our work also provides a promising framework for designing and fabricating high-performance elastomeric polymer materials via simulation and experiment.

AbstractThe evolutionary speed hypothesis (ESH) states that the molecular evolutionary rates of plants in the warm areas are higher than that in the cool areas. Nevertheless, largely due to the scarcity of molecular data from lower taxonomic lineages, ESH remains elusive in plants. In this study, we comprehensively conducted genome-wide comparative analyses of a total of 76 chloroplast (cp) genomes of the bamboos (Poaceae: Bambusoideae), with 10 of them newly generated, to test the ESH via investigating the potential association between their cp genome evolutionary rate and geographical distribution pattern. The results showed extreme heterogeneity of the evolutionary rate within the bamboos, with the lowest value found in temperate bamboos (tribe Arundinarieae) being approximately 1/4 of that in the tropical ones (tribe Olyreae). All the 91 non-coding loci and 75 coding loci evolve consistently faster in tribe Olyreae than that in tribe Arundinarieae. Most of the non-coding (82 out of 91) and coding (73 out of 75) loci in the tropical woody bamboos (tribe Bambuseae) also evolve faster than those in the temperate woody bamboos (tribe Arundinarieae). Moreover, the split of tropical and temperate bamboos was apparently accompanied with the change of cp genome evolutionary rate. This is by far the first case using cp genome data to support the ESH via showing the tropical plants evolve faster than their closely related temperate ones, and will shed new light on our understanding of ESH and the adaptation of plants.

Polar stratospheric clouds (PSCs) play a key role in Arctic amplification and stratospheric ozone destruction in polar regions. In this paper, we used the CALIPSO data to analyze the spatiotemporal distribution of Arctic PSCs from 2006 to 2021. We found that Arctic PSCs mainly appear in December, peak in late December and early January, disappearing in late February and early March. PSCs can extend from heights near the tropopause to over 25 km. However, there is the lowest fraction of PSCs in the 2014/2015 winter. This study found that the temperature in the 2014/2015 winter was warmer than the 15‐year average temperature, with the lowest temperature slightly below the PSCs formation temperature of about 5 K. The formation of the Ural blocking high accompanied by the poleward propagation of the planetary wave caused a sudden stratospheric warming (SSW) event on 3 January 2015, during which the warm air entered the polar vortex and divided it into two lobes. Additionally, a reduction in SO2column mass density before the SSW event resulted PSCs occurring with a frequency of only 0.148 and dissipating rapidly in December. Moreover, the concentration of H2O and HNO3in the gravitational settling process of PSCs decreased by 20–50%, the reduction of condensation nuclei made PSCs with the highest frequency of 0.074 in February appear briefly and then disappear. The chemical and dynamic analysis of PSCs formation is needed to further understand the spatiotemporal distribution of Arctic PSCs and to better predict future Arctic amplification and ozone destruction. Polar stratospheric clouds (PSCs) influence polar ozone depletion by providing a reaction interface and also influencing surface temperature changes through longwave radiation effects. Previous studies on polar stratospheric clouds mainly focus on the Antarctic, and few studies on the temporal and spatial distribution characteristics of Arctic PSCs over long timescales. Therefore, by studying the spatial and temporal distribution of PSCs in the Arctic, we found that the spatial and temporal distribution of PSCs in the Arctic has obvious interannual variation compared with that in the Antarctic. The stratospheric sudden warming (SSW) events that occur almost every 2 years in the Arctic cause great interannual variations of the Arctic polar vortex and thus affect the distribution of Arctic PSCs. Moreover, there is the least and almost none occurrence of PSCs in the 2014/2015 winter, the chemical and dynamic analysis found that SSW, decrease of SO2, H2O, and HNO3concentration are not conducive to the formation of PSCs. It is of great significance to study the influencing factors of Arctic PSCs formation and provide a new basis for further prediction of Arctic amplification and ozone destruction. The fraction of Arctic polar stratospheric clouds (PSCs) during 2014/2015 winter was the lowest observed in the past 15 yearsThe splitting of polar vortex and the rise in temperature caused by sudden stratospheric warming (SSW) inhibited the formation of PSCsThe decrease in stratospheric sulfur dioxide, nitric acid, and water was unfavorable for the formation of PSCs before and after the SSW The fraction of Arctic polar stratospheric clouds (PSCs) during 2014/2015 winter was the lowest observed in the past 15 years The splitting of polar vortex and the rise in temperature caused by sudden stratospheric warming (SSW) inhibited the formation of PSCs The decrease in stratospheric sulfur dioxide, nitric acid, and water was unfavorable for the formation of PSCs before and after the SSW

The control of the self-assembly of the nanocrystals into ordered structures has been extensively investigated, but fewer efforts have been devoted to studying one-component polymer-grafted nanoparticles (OPNPs). Herein, through coarse-grained molecular dynamics simulation, we design a novel nanoparticle (NP) grafted with polymer chains, focusing on its self-assembled structures. First, we examine the effects of length and density of grafted polymer chains by calculating the radial distribution function between NPs, as well as through direct visualization. We observe a monotonic change of the arranged morphology of grafted-NPs as a function of the density of grafted polymer chains, which indicates that the increase of the grafting density contributes to the order of the morphology. Meanwhile, we find that much longer grafted polymer chains worsen the regularity of the morphology. Then, we probe the influence of the stiffness of grafted polymer chains (denoted by Kranging from 0 to 500) on the order of grafted-NPs, finding that the order of the structure exhibits a nonmonotonic behavior as a function of Kat moderate grafting density. For high grafting density, the order of the morphology is initially enhanced and becomes saturated as a function of K. For the effect of Kon the stress–strain behavior, the system with the lowest order demonstrates the most remarkable reinforced mechanical behavior for both low and high grafting density. Last, we establish the phase diagram by varying the stiffness and density of the grafted polymer chains, which contains the amorphous, ordered, and superlattice structures, respectively. In general, our simulated results provide guidelines to tailor the self-assembly of the OPNPs by taking advantage of the length, density, and stiffness of grafted polymer chains.

Aiming at high-strength damping elastomers, the pre-cross-linked sliding graft copolymer (SGC) is incorporated into a nitrile rubber (NBR). The microstructure characterizations reveal that SGC phase is dispersed in NBR matrix fairly uniformly with a distinct interphase. As SGC content increases, the loss factor of SGC/NBR blends gradually increases. The improved damping properties of SGC/NBR blends are attributed to the intrinsic high damping characteristics of SGC and the formed interfacial hydrogen bonds. In addition, the mechanical properties of SGC/NBR blends are unexpectedly improved. The tensile strength of SGC/NBR (20/100) is increased by 170%, comparing to that of neat NBR. The significantly increased tensile strength is ascribed to the increased orientation of NBR chains, because of the “pulley effect” of SGC and the successive rupture/reassociation of interfacial hydrogen bonds. The high damping and mechanical properties of SGC/NBR blends make them potential materials for use in isolation rubber bearings applications.

An antifouling ethylene-vinyl acetate copolymer (EVA) coating with halloysite clay nanotubes loaded with maleimide (TCPM) is prepared. Such antifoulant encapsulation allowed for extended release of TCPM and a long-lasting, efficient protection of the coated surface against marine microorganisms proliferation. Halloysite also induces the composite’s anisotropy due to parallel alignment of the nanotubes. The maleimide loaded halloysite incorporated into the polymer matrix allowed for 12-month release of the bacterial inhibitor preventing fouling; it is much longer than the 2–3 month protection when TCPM is directly admixed into EVA. The antifouling properties of the EVA-halloysite nanocomposites were tested by monitoring surface adhesion and proliferation of marine V. natriegensbacteria with SEM. As compared to the composite directly doped with TCPM-antifoulant, there were much less bacteria accumulated on the EVA-halloysite-TCPM coating after a 2-month exposure to seawater. Field tests at South China Sea marine station further confirmed the formulation efficiency. The doping of 28 wt % TCPM loaded halloysite drastically enhanced material antifouling property, which promises wide applications for protective marine coating.

Previous studies have revealed a negative correlation between the East Asian winter monsoon and wintertime haze‐fog events in China. The winter monsoon reduces haze‐fog by advecting away aerosol particles and supplying clean air through cold waves. However, it is found that the frequency of haze‐fog events on subseasonal time scales displays no correlation with typical winter monsoon indices. The results show that the accumulating and maintaining effects of calm weather related to the Siberian High, which is also a part of the monsoon circulation system, are equally important for the development of haze‐fog events during winter. Correlation analysis indicates that subseasonal variations in haze‐fog are closely related to the intensity of the Siberian High (r= 0.49). The Siberian High may increase the occurrence of haze‐fog events by reducing the near surface wind speed and enhancing the stratification stability. To quantify the contribution of these diverse effects of the winter monsoon on the variations in haze‐fog events, we analyzed haze‐fog events during periods of cold wave activity and calm weather separately and contrasted the relative contributions of these two effects on different time scales. On the subseasonal scale, the effect of the Siberian High was 2.0 times that of cold waves; on the interannual scale, the effect of cold waves was 2.4 times that of the Siberian High. This study reveals the dual effects of the East Asian winter monsoon on wintertime haze‐fog variations in eastern China and provides a more comprehensive understanding of the relationship between the monsoon and haze‐fog events. The Siberian High and cold waves have opposite effects on wintertime haze‐fog variationsThe Siberian High is the dominant factor that controls monthly haze‐fog variationsThe influence of the Siberian High on haze‐fog events will become more important in the future

Bio-based elastomer poly(diethyl itaconate-co-isoprene) (PDEII) was designed and synthesized by redox-initiated emulsion polymerization from diethyl itaconate and isoprene with mass ratio of 20:80, 40:60, 60:40 and 80:20. The number-average molecular weights of PDEII exceeded 140000 with relatively high yields. The physical properties of PDEII, such as glass transition temperatures and thermostability, were comparable with conventional synthetic elastomers and can be readily tuned by varying the ratio of diethyl itaconate to isoprene. The interaction between silica and PDEII macromolecules was effectively enhanced with the increase of diethyl itaconate content by endowing high polarity. The oil-resistance relevant properties of silica/ PDEII80 (80% diethyl itaconate, 20% isoprene) such as retention of tensile strength, retention of elongation at break and change in volume even surpass those of silica/NBR 240S after soaked in ASTM 3# oil at different temperatures.

A novel aging-resistant styrene–butadiene rubber (SBR) composite is prepared using the antioxidant N-isopropyl-N′-phenyl-p-phenylenediamine (4010NA) loaded inside of halloysite clay nanotubes and used as filler. Loading the antioxidant inside of halloysite allows for its sustained release for nine months in the rubber matrix. By utilizing modified halloysite, the antioxidant concentration in this rubber nanoformulation is tripled without causing “blooming” defects. Furthermore, the halloysite is silanized to enhance its miscibility with rubber. The aging resistance of SBR–halloysite composites is studied by comparing the mechanical properties before and after thermal-oxidative aging. A seven-day test at 90 °C shows preservation of mechanical properties, and no 4010NA blooming is observed, even after one month. Styrene–butadiene rubber with 27 wt % halloysite loaded with 4010NA shows marked increase in aging resistance and promising future of halloysite as a functional rubber filler.

A novel biomimetic surface modification method for meta-aramid (MPIA) fibers and the improvement on adhesion with rubber matrix was demonstrated. Inspired by the composition of adhesive proteins in mussels, we used dopamine (DOPA) self-polymerization to form thin, surface-adherent poly(dopamine) (PDA) films onto the surface of MPIA fibers simply by immersing MPIA fibers in a dopamine solution at room temperature. An epoxy functionalized silane (KH560) grafting was then carried out on the surface of the poly(dopamine)-coated MPIA, either by a “one-step” or “two-step” method, to introduce an epoxy group onto the MPIA fiber surface. The surface composition and microstructure of the modified MPIA was characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated successful grafting of KH560 on the PDA-coated MPIA surface. A single-fiber pull-out test was applied to evaluate the adhesion of MPIA fibers with the rubber matrix. Compared with the untreated MPIA fibers, the adhesion strength between the modified MPIA fibers by “one step” method with rubber matrix has an increase of 62.5%.

Strong interfacial interaction and nanodispersion are necessary for polymer nanocomposites with expectations on mechanical performance. In this work, montmorillonite (MMT) was first structurally modified by acid treatment to produce more silanol groups on the layer surface. This was followed by chemical modification of γ-methacryloxy propyl trimethoxysilane molecule (KH570) through covalent grafting with the silanol groups. 29Si and 27Al magic angle spinning (MAS) NMR results revealed the microstructural changes of MMT after acid treatment and confirmed the increase of silanol groups on acid-treated MMT surfaces. Thermogravimetric analysis indicated an increase in the grafted amount of organosilane on the MMT surface. X-ray diffraction (XRD) showed that the functionalization process changed the highly ordered stacking structure of the MMT mineral into a highly disordered structure, indicating successful grafting of organosilane to the interlayer surface of the crystalline sheets. The styrene–butadiene rubber (SBR)/MMT nanocomposites were further prepared by co-coagulating with SBR latex and grafted-MMT aqueous suspension. During vulcanization, a covalent interface between modified MMT and rubber was established through peroxide-radical-initiated reactions, and layer aggregation was effectively prevented. The SBR/MMT nanocomposites had highly and uniformly dispersed MMT layers, and the covalent interfacial interaction was finally achieved and exhibited high performance.

Using tetraethyl orthosilicate as a main raw material, silica nanofibers (SiNFs) were prepared through the combination of a sol–gel process and an electrospinning technique followed by pyrolysis. Surface modified electrospun SiNFs developed by self-polymerization of polydopamine on the surface (SiNFs-PDA) served as templates for the electroless plating of silver nanoparticles (Ag NPs), using glucose as a reducing agent. The electrical resistivity of silver coated SiNPs-PDA (SiNFs-PDA/Ag) was measured by the four-point probe method and was found to be as low as 0.02 mΩ·cm at room temperature. The morphology of SiNFs-PDA/Ag before and after the blending with silicon rubber indicated a strong interaction between the silver layer and the SiNFs-PDA. The electrical and mechanical properties of the silicon rubber filled with SiNFs-PDA/Ag were studied to demonstrate the conductive performance application of SiNFs-PDA/Ag.

Fiber-reinforced rubber composites (FRRC) are widely used as load-carrying and anti-pressure products. Resorcinol–formaldehyde–latex (RFL) dipping is widely used to improve interfacial adhesion between fiber and rubber in industry. Unfortunately, high volatility and toxicity of RFL do great harm to humans and the environment during the open dipping process. In this work, a phloroglucinol–terephthalaldehyde–latex (PTL) dipping system based on a low-toxic and low-volatile resin was developed to achieve equivalent interfacial adhesion instead of RFL ones. The reaction mechanism, chemical structure, and wettability changes on the Nylon-66 (PA66) fiber surface were characterized. The effect of the phloroglucinol/terephthalaldehyde (P/T) ratio on the dip pick-up, morphology of the fiber surface, and interfacial structure of FRRC was investigated to expound the interfacial adhesion mechanism. At the optimum P/T ratio (1/2.2), a dipping layer with uniform and suitable dip pick-up is achieved on the fiber surface, which ensures the formation of an appropriate graded interfacial layer with enough crosslinking density and modulus, under the synergistic effect of co-vulcanization with rubber, and accordingly strengthens interfacial adhesion. The dipped fiber possesses excellent interfacial adhesion, dynamic fatigue life, and storage stability at the RFL level. This new dipping system is environmentally friendly and easy to scale up without making any change in the process and equipment.

Thermoplastic polysiloxane-based polyurethane (Si-TPU) has been attracting a great deal of attention because of the dual advantages of polysiloxane and polyurethane. However, the strength of Si-TPU with a traditional structure is low, and improvement is urgently needed for diverse applications. Herein, we design a polysiloxane-based soft segment (SS) with two urethane groups at the end of the polysiloxane chain, and then we prepare a series of Si-TPUs through a designed SS, isophorone diisocyanate and 1,4-butanediol. Such structural design improves the polarity of the SS and endows more regular hydrogen bonds to the polymer molecular chain. As a result, the prepared Si-TPUs exhibit a good microphase separation structure, unprecedentedly high strength, repeatable processing, noncytotoxicity, shape memory properties, and three-dimensional printing capabilities. Moreover, a maximum tensile strength of Si-TPUs can reach 20.3 MPa, exceeding that of other existing Si-based polymer materials. Si-TPUs show great potential for biomedical applications.

The effects of pristine polystyrene microplastics (pMPs) without any pretreatment at different concentrations (0, 10, 20, 50, and 100 mg/L) on Phaeodactylum tricornutumBohlin at two initial algae densities (105and 106cells mL) were assessed in this study. Hormesis-like effects were found when microalgae grew with pMPs. The results showed that pMPs inhibited microalgae growth under a high concentration of microplastics tolerated by individual algal cell (low initial algae density) (up to −80.18±9.71%) but promoted growth when the situation was opposite (up to 15.27±3.66%). The contents of photosynthetic pigments including chlorophyll a, chlorophyll c and carotenoids showed resistance to pMPs stress under a low initial algae density and increased with time, but the opposite was true under a high initial algae density. Compared with the low initial algae density group, Qp received less inhibition, and NPQ (heat dissipation) also decreased under the high initial algae density. Under the low initial algae density, OJIP parameters such as Sm, N, Area, Pi Abs, Ψo, φEo, TRo/RC and ETo/RC were more perturbed initially and returned to the levels of the control group (without pMPs) over time, but they remained stable throughout the experiment at high initial algae density. These results show that microplastics in the marine environment may have different toxic effects on P. tricornutumat different growth stages, which is of great significance for understanding the impact of microplastics on marine microalgae and aquatic ecosystems.

A facile method was developed to fabricate highly electrically conductive aramid fibers. The immobilization of silver nanoparticles on the surface of polymetaphenylene isophthamide (PMIA) fibers was carried out by the functionalization of the PMIA fibers with poly(dopamine), followed by electroless silver plating. The poly(dopamine) (PDA) layer was deposited on the PMIA surface by simply dipping the PMIA substrate into an alkaline dopamine solution. The silver ions can be chemically bound to the catechol and indole functional groups in PDA. The silver ions were reduced into silver nanoparticles by using glucose as the reducing agent, resulting in a distinct silver layer on the PMIA surface. The obtained silver deposit was homogeneous and compact. The chemical composition of the modified PMIA fibers was studied by X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS), and the crystalline structure of the silver-coated PMIA fibers was characterized by powder X-ray diffraction (XRD). The topography of the modified PMIA fibers was investigated by scanning electron microscopy (SEM). The four-point probe resistivity meter was used to study the electrical resistivity of the silver-coated PMIA fibers, the results indicated that the electrical resistivity could be as low as 0.61 mΩ·cm, with a controllable silver content, and a satisfactory stability by ultrasonic treatment.

Highly conductive silver-coated glass fiber (GF) was fabricated in an efficient and environment-friendly way. When the GF powder was immersed in dopamine solution, an adherent self-polymerized poly(dopamine) (PDA) layer was formed on the GF surface. PDA acts as both a linker between GF and silver nanoparticles and a reducing agent for reducing silver ions to metallic silver. The silver nanoparticles can be chemically bound to the catechol and amine functional groups in PDA by electroless plating using glucose as reducing agent. Chemical and physical characterizations of the silver-coated GF were carried out by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Four-point probe was used to study the electrical resistivity of the silver-coated glass fibers. The results indicated that the silver coated on the GF surface was compact, uniform, continuous, and in a metallic crystal state. The silver content could be well controlled from 9.5 to 24 wt% by adjusting the reduction conditions. The electrical resistivity of the silver-coated glass fibers could be as low as 1.0 mO*cm.

A novel method for the preparation of highly conductive silver-plated aluminum (Al) microspheres was demonstrated. The surface of the aluminum microspheres was functionalized by a bioinspired polydopamine (PDA) coating. Electroless plating of silver was then carried out on the functionalized aluminum microspheres. An aqueous solution of silver nitrate is used as silver precursor and glucose is used as reducing reagent. The overall procedure is fast, simple, nontoxic, and controllable. The surface compositions and the crystalline structure of the modified aluminum microspheres were studied by x-ray photoelectron spectroscopy (XPS) and x-ray diffraction, respectively. XPS results show that the Al-PDA surfaces were successfully deposited with polydopamine and were ready for electroless deposition of silver. Scanning electron microscopy (SEM) was used to study the morphology of the Al-Ag bimetallic particles. SEM results show that the silver-plated aluminum core-shell microspheres have a continuous, uniform, and compacted silver layer. The as-prepared Ag/Al particles possess high electrical conductivity.

Reflective and surface conductive flexible polyimide (PI) films were prepared by the incorporation of silver(I) acetate and 1,1,1‐trifluoro‐2,4‐pentanedione into a dimethylacetamide solution of several poly(amic acid)s which were prepared from dianhydrides and diamines. Thermal curing of the silver(I)‐containing poly(amino acid)s precursor led to cycloimidization of the PI with silver(I) reduction and formation of a reflective and conductive silvered surface at about 13 wt % silver. Effects on silver particles migration and aggregation were discussed in this article. The results indicated that the PI structures with flexible chains and groups easily fabricate the silvered films, with both reflective and conductive characteristics. With the forced air condition, the evaporation rate of the solvent and water increases, which facilitates the migration of silver particles to give reflective and conductive silvered surfaces. Films were characterized by transmission electron microscopy, scanning electron microscopy, and tapping‐mode atomic force microscopy. Electrical conductivity, reflectivity, and dynamic mechanical thermal analysis were performed on the metallized films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2218–2225, 2006.

The manufacturing industry today faces a highly volatile market in which manufacturing systems must be capable of responding rapidly to market changes while fully exploiting existing resources. Reconfigurable manufacturing systems (RMS) are designed for this purpose and are gradually being deployed by many mid-to-large volume manufacturers. The advent of RMS has given rise to a challenging problem, namely, how to economically and efficiently reconfigure a manufacturing system and the reconfigurable hardware within it so that the system can meet new requirements. This paper presents a solution to this problem that models the reconfigurability of a RMS as a network of potential activities and configurations to which a shortest path graph-searching strategy is applied. Two approaches using the A* algorithm and a genetic algorithm are employed to perform this search for the reconfiguration plan and reconfigured system that best satisfies the new performance goals. This search engine is implemented within an AI-based computer-aided reconfiguration planning (CARP) framework, which is designed to assist manufacturing engineers in making reconfiguration planning decisions. Two planning problems serve as examples to prove the effectiveness of the CARP framework.

The manufacturing industry today faces a highly volatile market in which manufacturing systems must be capable of responding rapidly to market changes while fully exploiting existing resources. Reconfigurable manufacturing systems (RMS) are designed for this purpose and are gradually being deployed by many mid-to-large volume manufacturers. The advent of RMS has given rise to a challenging problem, namely, how to economically and efficiently reconfigure a manufacturing system and the reconfigurable hardware within it so that the system can meet new requirements. This paper presents a solution to this problem that models the reconfigurability of a RMS as a network of potential activities and configurations to which a shortest path graph-searching strategy is applied. Two approaches using the A* algorithm and a genetic algorithm are employed to perform this search for the reconfiguration plan and reconfigured system that best satisfies the new performance goals. This search engine is implemented within an AI-based computer-aided reconfiguration planning (CARP) framework, which is designed to assist manufacturing engineers in making reconfiguration planning decisions. Two planning problems serve as examples to prove the effectiveness of the CARP framework.

Surface modification of two types of fluorinated polyimide (FPI) films, either by plasma polymerization and deposition of 4-vinylpyridine (4VP) or by UV-induced graft copolymerization with 4VP under atmospheric conditions, was carried out for adhesion enhancement with the electrolessly deposited copper. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) results revealed that the pyridine groups in the plasma polymerized 4VP (pp-4VP) layer could be preserved to a large extent under proper glow discharge conditions. The grafted 4VP layer with well-preserved pyridine groups was used not only as the chemisorption sites for the palladium complexes (without the need for prior sensitization by SnCl2) during the electroless plating of copper, but also as an adhesion promotion layer for the electrolessly deposited copper. The T-peel adhesion strength of the electrolessly deposited copper with both the 4VP plasma-polymerized FPI (pp-4VP-FPI) film and the 4VP graft-copolymerized FPI (4VP-g-FPI) film was much higher than that of the electrolessly deposited copper with the pristine or the Ar plasma-treated FPI films. The high adhesion strength between the electrolessly deposited copper and the surface-modified FPI film was attributed to the fact that the plasma-polymerized and the UV graft-copolymerized 4VP chains were covalently tethered on the FPI surfaces, as well as the fact that these grafted 4VP polymer chains were spatially and reactively distributed into the copper matrix.

A novel method of constructing nanostructures on the surface of aramid fiber (AF) was demonstrated in this article. Through the π–π* interaction between the aramid nanofiber (ANF) and graphene (G), the G/ANF dispersion stably existed in water. In an alkaline solution of tannic acid (TA) and polyethyleneimine (PEI), a TA/PEI (TP) layer was deposited on the surface of AF to introduce functional groups. Then, the modified AF was impregnated with the G/ANF dispersion to construct surface nanostructures to enhance the interfacial adhesion between the fiber and rubber. The results showed that the H pull-out force of the AF and rubber after impregnating with G, ANF, and G/ANF was increased by 15.3, 21.5, and 84.7%, respectively, compared with the untreated AF. The Raman spectroscopy and SEM results show that there is a π–π* interaction between G and ANF, and the ANFs are firmly attached to the surface of G. The hybrid G/ANF nanofiller can form 3D nanostructures on the surface of AF to improve the mechanical interlocking and stress transfer between the fiber and the rubber matrix, thereby achieving excellent interfacial adhesion while maintaining the excellent mechanical properties of AF.

Carbon dots (CDs) have gained increasing attention in the elastomer composites due to their unique physical and chemical properties. Nevertheless, due to high hydrophilicity of most kinds of CDs, it is difficult to achieve a fine CDs dispersion within the non-polar rubbers by traditional melt milling, especially when the CDs loading is high. To tackle this problem, we propose a simple and cost-effective strategy, i.e., the combination of slurry compounding and in-situcompatibilizing, to prepare the rubber/CDs composites. The CDs slurry was simply prepared by mixing the CDs powder with water. Subsequently, the slurry along with the compatibilizer (polybutadiene grafted with maleic anhydride, BR-g-MAH) were compounded with rubber via open milling. The resulted rubber composites exhibited significantly improved mechanical properties. More importantly, the CDs endowed the rubber with exceptional antioxidative property. We envisage that this scalable yet environmentally-friendly strategy may pave the way for industrial-scale utilization of CDs in the elastomer and beyond.

Background: Non-small cell lung carcinoma (NSCLC) is a common malignant tumor with poor prognosis. CircRNA-100876 has been considered to be involved in NSCLC. However, the mechanism by which circRNA_100876 mediated the progression of NSCLC remains unclear.Methods: CCK8 assay and immunofluorescence were used to detect cell proliferation. Flow cytometry and transwell assay were performed to analyze cell apoptosis, migration and invasion, respectively. Verification of possible target for circRNA_100876 and related miR-636 were done using luciferase assay. In addition, western blot was performed to detect the protein expressions in NSCLC cells.Results: Silencing of circRNA_100876 notably inhibited the proliferation of NSCLC cells. Moreover, downregulation of circRNA_100876 significantly induce the apoptosis of NSCLC cells via mediation of apoptosis-related proteins. In addition, silencing of circRNA_100876 significantly inhibited migration and invasion of NSCLC cells. MiR-636 was the downstream target of circRNA_100876. Meanwhile, RET was the direct target of miR-636. Finally, circRNA_100876 shRNA2 notably suppressed the progression of NSCLC through PI3K/Akt signaling.Conclusion: CircRNA_100876 knockdown notably suppressed the progression of NSCLC through regulation of miR-636/RET axis, which may serve as a potential target for treatment of NSCLC.

The abundant dust particles from widespread deserts in East Asia play a significant role in regional climate and air quality. In this study, we provide a comprehensive evaluation of the widely used Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue (DB) aerosol retrievals in desert regions of East Asia using ground‐based observations over eight sites of the China Aerosol Remote Sensing Network (CARSNET). Different from their well‐characterized performance in urban and cropland areas around the globe, DB aerosol optical depth (AOD) retrievals exhibit underestimation across the deserts in East Asia. We found that 38%–96% of satellite values fall out of an expected‐error envelope of ±(0.05 + 20%AODCARSNET), with the worst performance in Taklimakan Desert. In particular, DB retrievals erroneously give a nearly constant low values of 0.05 in Taklimakan Desert when AOD is below 0.5, which does not match with variation of moderate dust plumes. Comparison with Multi‐angle Imaging SpectroRadiometer AOD shows that a similar underestimation is prevalent over the extensive deserts. Inversion of sky light measurements show that single scattering albedos of the yellow dust in East Asia are mostly below 0.9 at 440 nm, much lower than the “whiter” and “redder” dust models applied in the DB algorithm. On the other hand, overestimation of surface reflectance dominantly contributes to the significant low constant AOD values in MODIS DB retrievals in Taklimakan Desert. These large biases, however, can be substantially reduced by considering unique characteristics of aerosols and surface over the arid regions in East Asia. Comprehensive evaluation of MODIS Deep Blue retrievals was conducted in deserts of East Asia with CARSNET observationsMODIS Beep Blue retrievals obviously underestimates the dust loading in East AsiaThe large bias can be substantially improved by considering the unique characteristics of aerosol and surface in East Asia

An aging resistant styrene-butadiene rubber (SBR) composite was prepared by using N-isopropyl-N'-phenyl-p-phenylenediamine (antioxidant 4010NA) loaded halloysite nanotube (HNT) as filler. The antioxidant loaded in the tube lumens of HNTs allowed for sustained released through HNT openings, provided longer supply of antioxidant in rubber composite and enhanced the aging resistance of rubber. Surface modifying of HNTs with silane coupling agent was used to improve the performance of SBR/HNTs nanocomposites. The aging resistance of SBR/HNTs was studied by oxygen adsorption and heat aging method. The antioxidant loaded HNTs not only worked as fillers for better mechanical properties but also can be used for improving aging resistant.

Highly conductive silver-coated glass fiber (GF) was fabricated in an efficient and environment-friendly way. When the GF powder was immersed in dopamine solution, an adherent self-polymerized poly(dopamine) (PDA) layer was formed on the GF surface. PDA acts as both a linker between GF and silver nanoparticles and a reducing agent for reducing silver ions to metallic silver. The silver nanoparticles can be chemically bound to the catechol and amine functional groups in PDA by electroless plating using glucose as reducing agent. Chemical and physical characterizations of the silver-coated GF were carried out by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Four-point probe was used to study the electrical resistivity of the silver-coated glass fibers. The results indicated that the silver coated on the GF surface was compact, uniform, continuous, and in a metallic crystal state. The silver content could be well controlled from 9.5 to 24 wt% by adjusting the reduction conditions. The electrical resistivity of the silver-coated glass fibers could be as low as 1.0 mΩ·cm.