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Currently, the development of high-performance protonic ceramic cells (PCCs) is limited by the scarcity of efficient mixed protonic-electronic conducting oxides that can act as air electrodes to satisfy the high protonic conductivity of electrolytes. Despite the extensive research efforts in the past decades, the development of mixed protonic-electronic conducting oxides still remains in a trial-and-error process, which is extremely time consuming and high cost. Herein, based on the data acquired from the published literature, the machine-learning (ML) method is introduced to accelerate the discovery of efficient mixed protonic-electronic conducting oxides. Accordingly, the hydrated proton concentration (HPC) of 3200 oxides is predicted to evaluate the proton conduction that is essential for enhancing the electrochemical performances of PCCs. Subsequently, feature importance for HPC is evaluated to establish a guideline for rapid and accurate design and development of high-efficiency mixed protonic-electronic conducting oxides. Thereafter, screened (La

Ammonia is not only an important platform chemical for industrial and agricultural use but is also a novel energy‐carrying molecule. The electrochemical reduction method for ambient ammonia synthesis is emerging as a promising strategy for the replacement of the current Haber–Bosch ammonia synthesis method, which consumes a large amount of energy and natural gas (hydrogen resource) while releasing substantial greenhouse gases (eg, carbon dioxide). The challenges in electrochemical ammonia synthesis, also known as nitrogen reduction reaction, primarily include the cleavage of extremely stable N≡N bonds and the competitive hydrogen evolution reaction in routine aqueous media, which significantly leads to a low production rate and Faradaic efficiency. The rational design and engineering of the electrocatalyst/electrolyte interface are crucial to address these challenges. Herein, recent achievements for catalyst/electrolyte interface engineering are reviewed to provide insights into enhancing the production rate and Faradaic efficiency. Perspectives on future research and development of the electrochemical ammonia synthesis from theory to practice will be provided.

Oil content is an important parameter of tar sands resource evaluation and utilization. They are time-consuming, large toxicity solvent, complex operation, and sample ruining problems in traditional oil content determination method of tar sands. Reflection spectroscopy can provide a fast and nondestructive method in the analysis of material composition. Therefore, the oil content of tar sands can be calculated quickly and nondestructively by analyzing the characteristics of high spectral data of tar sands. But the bands of high spectral data are too many and the data are large redundancy. In order to improve the utilization rate of spectral data, the correlation coefficient was used as the measuring index for screening the sensitive band of hydrocarbons in tar sands. On the one hand, the oil rate inversion models were established by hydrocarbon spectral index constructed by the sensitive spectral bands of hydrocarbon. On the other hand, the absorption features were quantified by spectral absorption characteristic parameters and the inversion models of oil content were established. The results showed that the selected bands by correlation coefficient could be used to indicate the oil content; the spectral index models by first-order differential treatment were better than the original reflectance; the oil content inversion models constructed by the spectral absorption area of the seven characteristic absorption bands were superior to other forms.

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The electrocatalytic oxygen reactions, i.e. oxygen reduction/evolution reactions (ORR/OER), play a key role in electrochemical energy conversion and storage devices, including fuel cells, electrolyzers, and metal-air batteries, and have attracted significant attention in the past decades. Platinum-group metal (PGM)-free materials have been intensively investigated as alternatives to replace the well-accepted but costly PGM-based catalysts such as Pt for ORR and Ir/Ru (oxides) for OER. Particularly, metal-organic framework (MOF)-derived carbon materials are emerging PGM-free catalysts for ORR/OER. So far, excellent works have been achieved to enhance the activity and durability of the MOF-derived PGM-free catalysts. It is the occasion to promote the PGM-free catalysts to the next level of application, i.e. in real devices. However, ORR/OER in real devices are potentially subject to the porosity related challenges, e.g. electron/mass transfer issue and active site isolation in organic Li-air batteries. To address these challenges, the rational design of porous electrocatalyst for devices is required. In this review, we summarize the most recent progress of MOF-derived carbon materials for ORR/OER with the focus on not only the active site engineering but also the design of porous structure. We also provide perspectives on the rational design of PGM-free catalysts using MOF as precursors.

The Lijiang River Basin is associated with a classic karst terrain characterized by conical hills that are referred to as karst towers. To date, few quantitative studies have been conducted on the geomorphological development of the river basin, in part, because it covers a large area of about 5800 km2, making it difficult to carry out a comprehensive quantitative analysis using traditional methods. This study using Landsat-8 OLI images and a digital elevation model firstly assesses the longitudinal profile of the Lijiang River, calculates the average bifurcation (bifurcation) ratio of the basin’s drainage network, and conducts a hypsometric (elevation) analysis of the Lijiang Basin. The stage of geomorphological development is quantitatively constrained. It is concluded that the Lijiang River is currently in the old stage of geomorphological development, the stream systems in the Lijiang River Basin are in a relatively balanced developmental stage and the geomorphological development is dominated by the old-stage (monadnock) landforms.

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play crucial roles in energy conversion and storage devices. Particularly, the bifunctional ORR/OER catalysts are core components in rechargeable metal–air batteries, which have shown great promise in achieving "carbon emissions peak and carbon neutrality" goals. However, the sluggish ORR and OER kinetics at the oxygen cathode significantly hinder the performance of metal–air batteries. Although noble metal-based catalysts have been widely employed in accelerating the kinetics and improving the bifunctionality, their scarcity and high cost have limited their deployment in the market. In this review, we will discuss the ORR and OER mechanisms, propose the principles for bifunctional electrocatalysts design, and present the recent progress of the state-of-the-art bifunctional catalysts, with the focus on non-noble metal-based materials to replace the noble metal catalysts in Zn–air batteries. The perspectives for the future R&D of bifunctional electrocatalysts will be provided toward high-performance Zn–air batteries at the end of this paper.

International audience; The worldwide fossil fuel shortage and resultant environmental issues urgently require renewable and clean energy technologies. Electrocatalytic oxygen reduction/evolution reactions (ORR/OER) are the cornerstone for renewable energy conversion and storage devices, such as fuel cells, electrolyzers, unitized regenerative fuel cells, and metal‐air batteries. High‐performance electrocatalysts are required to improve the ORR and OER activity and stability, and thus the device performance. Therefore, appropriate strategies and methods are crucial for the rational design and synthesis of highly efficient ORR/OER electrocatalysts. On the other hand, the conventional platinum‐group‐metal‐based (PGM‐based) catalysts, such as Pt and Ir/Ru (oxides), have been facing great challenges, including limited resources and high cost, leading to them being less competitive in the market. Thus, a lot of effort has been devoted to developing alternative PGM‐free ORR/OER catalysts, which, however, still suffer from low activity and insufficient stability. In this review paper, the strategies for engineering high‐performance PGM‐free ORR and OER electrocatalysts are discussed by reviewing the most recent advances. At the end, perspectives on the methods to rationally design PGM‐free ORR and OER catalysts are provided.

By comparing and analyzing, we obtain the conclusion that photovoltaic (PV) inverter has good reactive power regulation ability as it has similar topology and control strategy with SVG. A typical inverter power generation model of a centralized grid-connected PV power plant is built on the PSCAD/EMTDC platform. The reactive power adjustment ability of the inverter under several specific conditions is analyzed in simulation. The simulation result shows that the dynamic reactive power response time of the inverter is within 30ms and the reactive power capacity is higher than the requirement of the national standard. The reactive power regulation ability of the plant inverter is modified by combining the rapid power regulation technology of the PV power plant and ideal test results are obtained in the on-site test.

The oil content of oil sands is an important factor in oil sand resource evaluation. In this study, we use spectral reflectance to study the oil content parameter. The spectrograph can be used to determine the target spectral reflectance directly, using a fiber-optic probe, without destroying samples or using chemical reagents, which has the advantage of quick measurement and analysis. This paper documents the acquisition of hyperspectral data in the range of 350–2500 nm through spectrometry of oil sand samples. We process the original reflectivity data using the first-order and second-order differentials and then calculate and analyze the correlation coefficient with reflectivity of oil sands and the first and second derivatives of reflectance. Based on the characteristics of the correlation coefficient graphs, we determine the wave bands sensitive to oil content and verify that using hyperspectral data in the study of oil content is feasible.

With the development of VSC-HVDC and engineering applications, establishing a modular multilevel converter (MMC) platform is extremely important for simulation research and training. In this study, a back-to-back MMC emulation system with a converter station level is developed. Dynamic tests are performed to verify the stability performance and the dynamic performance of the respective physical devices under asynchronous interconnection conditions. The results show that the system can perform automatic control for the sequence of blocking, uncontrolled charging, controlled charging, and unlocking operations. A remarkable power quality effect is obtained by using a controller for circulating current suppressing (CCS). Using a visual station operation interface, the dynamic index of the power step test is found to conform to the test standard, and the system exhibits stable operation.

In this study, the Chang’E-2 microwave radiometer (CELMS) data are employed to study the thermophysical features of the regolith in the western lunar farside, including Giordano Bruno - the youngest lunar crater of its size. The results are as follows. Firstly, the distribution of the rocks with depth is different in Bruno, King, and Necho craters. Secondly, abundant cold anomalies and one hidden hot anomaly are discovered. Thirdly, at least seven hidden linear structures are discovered, some of which hinting the impacting process of Bruno crater.

Grafting different kinds of nanomaterials on the surface of carbon fibers has been a feasible strategy for fabricating novel advanced materials. However, the bond strength between the nanomaterials and carbon fibers is a major challenge that limits the final properties of the materials. In this study, ZnO nanorods (NRs) were synthesized in an aqueous solution over ZnO films, which were deposited using a radio frequency magnetron sputtering technique. The experimental conditions for the magnetron sputtering process were designed based on an orthogonal test, and the ZnO islands exhibited different shapes and sizes under different deposition conditions. ZnO NRs, which were synthesized on all ZnO films, present the same hexagonal prism shape. In addition, TEM images show that ZnO NRs, ZnO films, and graphite structure of carbon fiber present a lattice matching that makes it possible to achieve an ultra-high bond strength of ZnO NRs. The results obtained for interfacial shear strength show that the bond strength of ZnO NRs is strongest when deposition time, substrate temperature, pressure ratio of Ar and O2, and power are 60 min, 200 °C, 0.15, and 200 W, respectively. We demonstrate that the higher crystallinity and uniformity of ZnO films result in a better bond strength of ZnO NRs.

Nanogenerators (NGs) based on the piezoelectric property of ZnO nanowires (NWs) have become an important component to harvest mechanical energy from the environment. In one category of ZnO NGs, the high-work function noble metal electrode is applied to deflect ZnO NWs, and electricity is generated due to the Schottky barrier formed between ZnO NWs and the noble metal. Herein, an insulating layer was used to replace the expensive noble metal to accumulate net charge, and a novel NG was composed by carbon fibers (CFs) and ZnO NWs. Because of a relative slip among CFs, ZnO NWs would generate inner potential by bending each other. Due to the combination of an enormous number of ZnO NWs, an electric output of 2 mV and 0.2 nA was generated. Current–voltage curves indicated the entire ohmic contact of the designed NG, while electrochemical impedance spectroscopy demonstrated the existence of an interface barrier. Since a noble metal electrode was avoided in the ZnO NG, the manufacturing cost was reduced and the fabrication process was simplified. This study proposes a novel strategy for designing feasible ZnO NG in extensive applications.

The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

The continuous evolution toward electronics with high power densities and integrated circuits with smaller feature sizes and faster speeds places high demands on a set of material properties, namely, the electrical, thermal, and mechanical properties of polymer dielectrics. Herein, a supramolecular approach is described to self-healable polymer nanocomposites that are mechanically robust and capable of restoring simultaneously structural, electrical, dielectric, and thermal transport properties after multiple fractures. With the incorporation of surface-functionalized boron nitride nanosheets, the polymer nanocomposites exhibit many desirable features as dielectric materials such as higher breakdown strength, larger electrical resistivity, improved thermal conductivity, greater mechanical strength, and much stabilized dielectric properties when compared to the pristine polymer. It is found that the recovery condition has remained the same during sequential cycles of cutting and healing, therefore suggesting no aging of the polymer nanocomposites with mechanical breakdown. Moreover, moisture has a minimal effect on the healing and dielectric properties of the polymer nanocomposites, which is in stark contrast to what is typically observed in the hydrogen-bonded supramolecular structures.

Fibrous carbon materials have been attracted many researchers' attentions. Carbon fibers have been developed as one of the most important industrial materials for modern science and technology since 1960s [1] . Due to the superior mechanical properties including high-specific strength and modulus, low density and thermal expansion, heat resistance, and chemical stability, carbon fibers as reinforcement materials have provided the impetus for researchers in developing high-performance composite materials. Nowadays, carbon fiber reinforced plastics (CFRP) are widely applied in the industries of aeronautic, aerospace, sporting goods, as well as new energy. The region between the fibers and matrix, contains unique micromechanical properties, is characteristically called the interphase and influence the bulk composite properties. Interface between fibers (reinforcements) and matrix is an important component for CFRP which may govern the CFRP performances [2] . For example, the interphase determines the off-axis strength and impact toughness of CFRP, environmental stability of CFRP and functional performance of CFRP. The effect of interface on composite can be achieved by regulating the composition, structure and distribution of the interface [3] . It has been proved that there has an optical interface for polymer based composite through the match of composite interface, reinforcement and polymer matrix. However, in terms of the smooth surface and chemical inertness of carbon fiber, the interface between carbon fiber and resin matrix is unsatisfactory. The interface should be modified and carefully controlled, which can be through by increasing the surface polarity of carbon fiber, improving the wettability between carbon fiber and resin, as well as promoting the chemical reaction. Obey these principles, the interfacial modification methods have been well developed. The universality of carbon fiber and polymer matrix, and the variability of the composite material forming process result in the complexity of polymer-based composites interface problems. Meanwhile the scale of the interface region is very small, it has great difficulty in characterizing the chemical structure, physical properties and mechanical characteristics. Recently, a series of effective characterization methods have been developed and initial interface characterization system is always being improved. With interface characterization techniques, the interfacial composition, structure morphology and micro-mechanical characteristics of interface can be researched easily, which can provide the basis for studying the interface physical and chemical properties. Hence interface characterization techniques not only are theory researches, but also have important practical significance for solving practical application problems of carbon fiber composites. Interface characterization techniques have become an important research direction of interface engineering research. In this paper, the researches in this field of carbon fiber interface were described, such as carbon fiber composite material characterization methods, interface control, and interfacial modification methods. With reference to the research achievements of a large number of scholars at present, so their current development trend were systemic concluded.

A three-dimensional (3-D) structured sensor of microcrystalline β-PbO2-coated carbon felt consisting of crisscrossing carbon fibers has been developed to determine chemical oxygen demand in wastewater. Each carbon fiber in the felt is coated by perfect octahedral β-PbO2 microcrystals. The unique structure makes it possess huge surface area and abundant active sites for generating hydroxyl radicals, thus exhibiting excellent performances. Results show a RSD within 5% as compared with the traditional standard method, a high sensitivity of 2.05 × 10−3 mA cm−2/mg L−1, a wide linear range of 50-5000 mg L−1, a correlation coefficient (R) of 0.993 and a detection limit of 3.9 mg L−1 (S/N = 3). Additionally, this electrode demonstrates excellent reproducibility, low cost and good stability. These properties enable the electrode to be used as a COD sensor for in situ determination in industry, showing a promising application perspective.

Trisilanollsobutyl polyhedral oligomeric silsesquioxane (SO 1450 POSS) has been uniformly grafted on the carbon fiber (CF) surface. The surface roughness (108.4 nm) of the CFs grafted with POSS was higher than that of the as-received CFs (57.9 nm). Dynamic contact angle analysis of the SO grafted CFs showed higher surface energy than that of the as-received CFs. After grafted with SO, the interlaminar shear strength of the unsaturated polyester (UPR) composites was 61 MPa, increased by 29.8% compared with that of the composites with the as-received CFs (47 MPa). The interfacial shear strength (IFSS) of SO grafted CFs/UPR composites was 88 MPa, significantly increased by 91% compared with that of the as-received CFs/UPR composites (46 MPa). The IFSS of the SO grafted CFs/UPR composites after hydrothermal ageing was 74 MPa with a decrease of just 16% compared with that of the as-received CFs/UPR composites (30 MPa) with a significant decrease of 35%. The tensile strength of the SO grafted CFs/UPR composites (1280 MPa) was 15% higher than that of the as-received CFs/UPR composites (1110 MPa). The impact energy of 1.52 J for the SO grafted CFs/UPR composites was higher than 1.00 J for the as-received CFs/UPR composites.

Silica spheres in nanoscale were prepared via sol–gel method and then sodium 4-styrene sulfonate was grafted onto the surfaces of SiO2 (PSS-SiO2) by surface-initiated atom transfer radical polymerization (SI-ATRP). Then, a negatively charged loose SiO2-PSS/polyethersulfone (PES) nanofiltration membrane with high flux was fabricated via phase inversion method. FT-IR and TEM results showed that SiO2 nanoparticles were synthesized and modified successfully. GPC results further proved the “living”/controlled behavior of SI-ATRP. The morphology, hydrophilicity of the membranes were investigated by SEM, static water contact angle and water ratio. The results revealed that the surface hydrophilicity and water permeability of hybrid membranes were greatly improved after adding SiO2-PSS and thus may enhance fouling resistance to a certain extent. The salt permeation and separation of dye/salt mixture of the hybrid membranes were significantly superior to the pure PES membrane, and the order of permeation for different salt solutions was NaCl > MgCl2 > MgSO4 > Na2SO4. When the content of SiO2-PSS was 3.0 wt%, the hybrid membrane showed optimal performance with IEC value of 0.07 mmol/g and pure water flux of 269.5 L m−2 h−1 and the rejections for all types of salts declined to under 11%. The above results indicated that SiO2-PSS incorporated into PES matrix played an important role in enhancing the performance of NF membranes, which may possess a significant impact on the application in dye purification and desalination.

Edge detection is an essential task in the interpretation of potential field data. In this paper, we present a new method to delineate the edges of the sources, which is based on the windowed corre...

The high energy irradiation was used to modify domestic aramid fiber-12 (DAF12) in epoxy chloropropane. The properties of the interphase between DAF12 and epoxy matrix systems were optimized. Scanning electron microscopy was employed to characterize the surface morphology of DAF12 and high energy irradiated fibers (HEI-DAF12) and composites de-bonding section. Atomic force microscopy showed the original smooth surface disappeared. Single fiber pull-out tests revealed that the interfacial shear strength of HEI-DAF12/epoxy composite was substantially improved by 45.17% after irradiation in 400 kGy dose. Dynamic contact angle analysis indicated the increased total surface free energy. The changes of elemental composition investigated via X-ray Photoelectron Spectrometer verified the increase polar groups on fiber surface caused by high energy irradiation.

Monofunctional (methacrylolsobutyl) and multifunctional (methacryl) polyhedral oligomeric silsesquioxane (POSS) were successfully grafted on a carbon fiber (CF) surface to enhance the interfacial strength of CF reinforced unsaturated polyester resin (UPR) composites. The silicon containing functional groups were obviously increased on the CFs after the successful grafting of POSS onto the CF surface. Both kinds of POSS were uniformly grafted on the CF surface and the surface roughness of the CFs grafted with methacryl POSS and methacrylolsobutyl POSS was almost the same (131.6 and 129.6 nm) but much higher than that of the as-received CFs (57.9 nm). Dynamic contact angle analysis of the CFs grafted with both POSS showed almost the same surface energy but higher than that of the as-received CFs. After being grafted with methacrylolsobutyl POSS, the interlaminar shear strength of the composites was 62 MPa, increased by 31.9%, however, in terms of methacryl POSS the value was 67 MPa, increased by 42.6% compared with that of the as-received CFs (47 MPa). The interfacial shear strength (IFSS) of the composites with methacryl POSS grafted CFs (93 MPa) was significantly increased by 102.2% compared with the composites with the as-received CFs (46 MPa) and is even higher than that of the composites with methacrylolsobutyl POSS grafted CFs (87 MPa). The impact energy of 1.72 J for the composites with methacryl POSS grafted CFs is higher than that of the composites with as-received CFs (1.00 J) and methacrylolsobutyl POSS grafted CFs (1.43 J).

The grafting of amino-POSS on the carbon fibers (CFs) surface was achieved through the reaction of the spiralphosphodicholor (SPDPC) grafted on the CFs surface with aminopropylphenyl polyhedral oligomeric silsesquioxane (amino-POSS). X-ray photoelectron spectroscopy (XPS) showed that the phosphorus, chlorine and silicon containing functional groups were obviously increased after the modifications. Both CFs grafted with SPDPC and CFs grafted with SPDPC plus amino-POSS have been used to prepare unsaturated polyester resin (UPR) composites. The grated SPDPC and grafted with a combined SPDPC and amino-POSS improved the interfacial performance of the CFs/UPR composites, respectively. Atomic force microscopy (AFM) results showed that the surface roughness of the CFs grafted with SPDPC was lower than that of the CFs grafted with a combined SPDPC and amino-POSS. Dynamic contact angle analysis of the CFs grafted with SPDPC showed higher wettability to UPR than that of the CFs grafted with a combined SPDPC and amino-POSS. Force modulation atomic force microscopy (FMAFM) and interlaminar shear strength (ILSS) were used to characterize the interfacial properties of the composites. After grafted with a combined SPDPC and amino-POSS, the ILSS of the composites was increased by 22.9% due to the well interfacial properties that were caused by the improvement of CFs surface roughness.

A new application of conventional electroless nickel plating to improve the interfacial properties of PBO fibers was reported. The relationship between surface morphology and interfacial properties of nickel-plated PBO fiber was explored. The continuous nickel coating consisted of nickel and phosphorus elements determined by Energy dispersive spectrometer (EDS) and transmission electron microscope (TEM), exhibiting high adhesive durability. The influence of bath temperature and plating time on the crystal structure, microstructure and mechanical properties of nickel-plated PBO fibers was systematically investigated. X-ray diffractometer (XRD) results revealed that the crystal structure among nickel-plated PBO fibers did not show differences. Scanning electron microscope (SEM) and Atomic force microscope (AFM) images showed that the process parameters had a great influence on surface morphology and roughness of nickel-plated PBO fibers, which could directly affect the interfacial properties of nickel-plated PBO fibers. Single fiber pull-out testing results indicated that the interfacial shear strength (IFSS) of PBO fibers after electroless nickel plating had a significant improvement, which reached maximum at 85 °C for 20 min. Single fiber tensile strength of nickel-plated PBO fibers was slightly lower than that of untreated one. Thermo gravimetric analysis (TGA) indicated that nickel-plated PBO fiber had excellent thermal stability.

We propose a novel method to uniformly graft high density carbon nanotubes (CNTs) onto carbon fiber (CF) using poly (acryloyl chloride) (PACl) as coupling agents. Compared to micromolecule couping agent previously reported in literature [2,3], PACl can supply much more active groups, which is beneficial for grafting high density CNTs onto CF surface. Moreover, in order to further increase the grafting density of CNTs, the solvothermal strategy was used for improving the reactive activity between CF and CNTs. After CNTs grafting treatment, there are still substantial amounts of reactive groups which can further react with various types of molecules to meet different requirements. In order to create chemical bonding between CF and unsaturated polyester (UP), CF-CNT was further grafted with undecylenic alcohol (UA) to get CF-CNT-UA hierarchical reinforcement. The interfacial adhesion of the resulting composites showed a dramatic improvement.

Conventional electroless nickel plating was utilized to enhance the interfacial properties of PBO fibers. Moreover, the possible interfacial shear strength (IFSS) enhancing reasons were investigated. The elemental composition, crystal structure and cross-sectional morphology of nickel-plated PBO fiber were characterized by energy dispersive spectrometer (EDS), X-ray diffractometer (XRD) and transmission electron microscopy (TEM), respectively. Ultrasonic exposure tests implied that the nickel coating exhibited high adhesive durability. Scanning electron microscopy (SEM) was employed to characterize the surface morphology of PBO fibers and the de-bonding surface morphology of PBO fiber composites. Atomic force microscopy (AFM) results showed that the surface morphology of nickel-plated PBO fiber was undulating, and its surface roughness (R a ) increased obviously. Single fiber pull-out tests showed that the IFSS increased from 40.4 to 56 MPa. Meanwhile, the nickel-plated PBO fiber maintained satisfactory tensile strength. Hygrothermal aging tests revealed that the nickel-plated PBO fiber had excellent hygrothermal aging resistance properties. Heat treatment results showed that IFSS was decreased with the increase of temperature.

To improve the interfacial properties in carbon fiber (CF)-reinforced unsaturated polyester (UP) composites, we directly introduced functionalized carbon nanotubes dispersed in the fiber sizing onto the fiber surface. For comparing the influence of polymer type on sizing effect, two different polymers (UP MR13006 and water-soluble epoxy (EP)) were used to prepare sizing agent. Morphology and surface energy of CFs were examined by scanning electron microscopy and dynamic contact angle analysis test. Tensile strength was investigated in accordance with ASTM standards. Mechanical properties of the composites were investigated by interlaminar shear strength (ILSS) and impact toughness. Test results indicate that TS, ILSS, and impact toughness were enhanced simultaneously. For UP matrix, the sizing agent containing UP has better reinforcing and toughening effect than the sizing agent containing water-soluble EP.

The mutual irradiated aramid fibers in 1,4-dichlorobutane was ammoniated by ammonia/alcohol solution, in an attempt to improve the interfacial properties between aramid fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS), and single fiber tensile testing were carried out to investigate the functionalization process of aramid fibers and the interfacial properties of the composites. Experimental results showed that the fiber surface elements content changed obviously as well as the roughness through the radiation and chemical reaction. The surface energy and IFSS of aramid fibers increased distinctly after the ammonification, respectively. The amino groups generated by ammonification enhanced the interfacial adhesion of composites effectively by participating in the epoxy resin curing. Moreover, benefited by the appropriate radiation, the tensile strength of aramid fibers was not affected at all. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44924.

Flexible energy-storage devices based on supercapacitors rely largely on the scrupulous design of flexible electrodes with both good electrochemical performance and high mechanical properties. Here, nitrogen-doped carbon nanofiber networks/reduced graphene oxide/bacterial cellulose (N-CNFs/RGO/BC) freestanding paper is first designed as a high-performance, mechanically tough, and bendable electrode for a supercapacitor. The BC is exploited as both a supporting substrate for a large mass loading of 8 mg cm–2 and a biomass precursor for N-CNFs by pyrolysis. The one-step carbonization treatment not only fabricates the nitrogen-doped three-dimensional (3D) nanostructured carbon composite materials but also forms the reduction of the GO sheets at the same time. The fabricated paper electrode exhibits an ultrahigh areal capacitance of 2106 mF cm–2 (263 F g–1) in a KOH electrolyte and 2544 mF cm–2 (318 F g–1) in a H2SO4 electrolyte, exceptional cycling stability (∼100% retention after 20000 cycles), and excellen...

A synergistic Pd–C catalytic hydrogenation of 4-pyridinecarboxamides straightforward to 4-piperidinecarboxamide hydrochlorides was developed in the presence of ClCH 2 CHCl 2 . It provided a novel strategy for highly efficient hydrogenation of pyridine nuclear by using low-cost Pd–C catalyst under mild conditions.