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Carbon nanotubes (CNTs)/carbon fiber (CF) reinforcements were synthesized under different catalyst compositions and reduction conditions. The effects of the catalyst, reduction temperature and reduction time on the surface morphology, graphitization, and single filament tensile strength of the prepared CNTs/CF samples were investigated. When nickel was used as the catalyst and copper as the catalyst promoter, with the increase of copper concentration, the catalytic activity increased. Thus, the carbon source was consumed more completely, improving the abundance of CNTs with good graphitization. And the effect of repairing CF defects was more obvious, hence the single filament tensile strength accordingly increased. Besides, the increase of catalyst reduction temperature and reduction time intensified the etching of CF by catalyst, and decreased the single filament tensile strength of CF. With the deposition of CNTs, the tensile strength of CF was enhanced in varying degrees. When the concentration of cooper was 0.01 mol/L with the reduction time of 10 min and reduction temperature of 450 °C, CNTs/CF had the highest tensile strength, which can reach up to 4.51 GPa. We determined that bimetallic catalysts could adjust the catalytic activity of nickel. The change of reduction time and temperature would affect the quality of CNTs, which was helpful to obtain high quality CNTs on CF surface and improve the mechanical properties of CNTs/CF and its composites. [ABSTRACT FROM AUTHOR]

Rice false smut (RFS) is a late-onset fungal disease that primarily affects rice panicle in recent years. Severe RFS can decrease the yield by 20–30% and severely affect rice quality. This research used hyperspectral remote sensing data from unmanned aerial vehicles (UAV). On the basis of genetic algorithm combined with partial least squares to select the feature bands, this paper creates a new method to use the Pearson correlation coefficient method and Instability Index between Classes (ISIC) method to further select characteristic bands, which further eliminated 27.78% of the feature bands when the model monitoring accuracy was improved overall. The prediction accuracy of the Gradient Boosting Decision Tree model and Random Forest model was the best, which were 85.62% and 84.10%, respectively, and the monitoring accuracy was improved by 2.22% and 2.4% compared with that before optimization. Then, based on the UAV hyperspectral data and the combination of characteristic bands selected by the three band optimization methods, the sensitive band ranges of rice false smut monitoring were determined, which were 698–800 nm and 974–997 nm. This paper provides an effective method of selecting characteristic bands of hyperspectral data and a method of monitoring crop diseases' using unmanned aerial vehicles. [ABSTRACT FROM AUTHOR]

A multi‐stage core‐expansion method is proposed here as one component of the integrative binding‐site/extender/core‐expansion (BEC) strategy. The conceptual deconstruction of the partitioning ligand into three editable parts draws our focus onto progressive core expansion and allows the optimization of both acetylene uptake and selectivity. The effectiveness of this strategy is shown through a family of eight cationic pore‐partitioned materials containing three different partitioning ligands and various counter anions. The optimized structure, Co3‐cpt‐tph‐Cl (Hcpt=4‐(p‐carboxyphenyl)‐1,2,4‐triazole, H‐tph=(2,5,8‐tri‐(4‐pyridyl)‐1,3,4,6,7,9‐hexaazaphenalene) with the largest surface area and highest C2H2 uptake capacity (200 cm3/g at 298 K), also exhibits (desirably) the lowest CO2 uptake and hence the highest C2H2/CO2 selectivity. The successful boost in both C2H2 capacity and IAST selectivity allows Co3‐cpt‐tph‐Cl to rank among the best crystalline porous materials, ionic MOFs in particular, for C2H2 uptake and C2H2/CO2 experimental breakthrough separation. [ABSTRACT FROM AUTHOR]

Highly efficient and multifunctional electromagnetic wave (EMW) absorbers which can be easily processed are desirably required. Herein, cupric ammonia is creatively adopted as the catalyst precursor of the in-situ growth of carbon nanotubes (CNTs) onto carbon fiber (CF) during chemical vapor deposition. Typically, when prepared at 750 °C, N/S co-doped bamboo-like amorphous CNTs/CF was successfully synthesized, while some Cu nanoparticles were remained in CNT forests. The sample obtains an excellent absorption toward EMWs, demonstrating a minimal reflection loss of −59.28 dB at 14.1 GHz with an ultrathin thickness of 1.42 mm. Concurrently, it is over a relatively broad effective absorption bandwidth (EAB) of 3.3 GHz (12.3–15.6 GHz) with 31% loading in the paraffin matrix. And the EAB value of CA-700 reaches 3.7 GHz (14.3–18 GHz) at merely 1.45 mm. The satisfying attenuation performance mainly originates from the synergistic effects of continuous three-dimensional conducting networks, abundant interfaces, sufficient defects, and the well impedance matching. Moreover, all as-prepared samples could be potentially used as reinforcements of resin matrix composites with high strength. Therefore, a facile route is provided to produce thin, lightweight, superior and high-strength EMW absorbing materials based on CF and CNTs. [ABSTRACT FROM AUTHOR]

• The receiver's 6-DOF model, considering the influence of multiwind disturbances and time-varying mass, are established. • The affine nonlinear form of 6-DOF nonlinear model is formulated to facilitate the design of nonlinear controllers. • Fixed-time extended state observers (FTESOs) are designed for each control loop to estimate the lumped disturbances. • A backstepping-based predefined-time anti-disturbance control (PTADC) framework including five subcontrollers is proposed. • The anti-disturbance and predefined-time stable performance of PTADC in a multi-loop system is proved. Aiming at the relative position-holding and velocity-holding control problems during the refueling phase of autonomous aerial refueling (ARR) missions, this paper proposes a predefined-time anti-disturbance control (PTADC) structure for receiver aircraft. First, a 6-degree-of-freedom (6-DOF) rigid model of the receiver in the refueling phase is established, with the time-varying mass, time-varying inertia, time-varying unbalanced moment, multiwind disturbances, and model uncertainties explicitly considered. Moreover, to facilitate the design of a nonlinear controller, the affine nonlinear form of the 6-DOF receiver model is formulated. Then, fixed-time extended state observers (FTESOs) are designed for each subsystem to estimate the lumped disturbances. By compensating for these estimated lumped disturbances, a backstepping-based PTADC structure with disturbance resistance and predefined-time convergence is developed to complete the refueling task. The performance of the entire closed-loop system is rigorously proven through Lyapunov functions. Finally, the effectiveness of the proposed refueling control framework is validated through numerical simulations. [ABSTRACT FROM AUTHOR]

Carbon fiber composites as pantograph slide materials are in the development stage, in which copper is the conductive phase, and the addition form and size need to be designed. Herein, the effects of the copper morphology, the size of the copper mesh on the performance, and the influence of the contact mode between the sliding plate and bracket on the temperature rise were compared and analyzed. The resistivity is 11.2 μΩ·m with the addition of 20 wt% copper mesh, a relative reduction of 91.77%. Importantly, the impact strength is increased by 14.19%, and the wear is reduced by 13.21%; hence, the copper mesh laid in layers is the ideal structure. Further study of the distribution and quality of the copper mesh shows that the resistivity is related only to the quality of the copper mesh; in addition, the number of layers of the copper mesh cannot exceed 16, and it is determined that the best type of copper mesh is 5#. Notably, the performance can be improved by appropriately reducing the thickness of the copper mesh and increasing the aperture while the sliding plate and the bracket are connected by copper mesh with conductive adhesive, which has the slowest heating rate of 2.27 °C/min and the smallest resistance. Therefore, the influence of copper content and distribution on the electrical conductivity are systematically investigated, and the mechanical properties and electrical conductivity are optimized through the design of the laminate structure of the compound material. [ABSTRACT FROM AUTHOR]

Carbon fiber (CF) has rarely been presented as a promising electromagnetic wave (EMW) absorber because of its excessive electrical conductivity. Herein, the continuous preparation of carbon nanotubes/carbon fiber (CNTs/CF) multiscale reinforcements and microwave absorbers was realized by one-step chemical vapor deposition (CVD) at different temperatures. Beneficial from the intertwined CNTs, good graphitization and crystallinity, and satisfactory epoxy resin wettability, CNTs/CF650 and its composites show excellent tensile, interfacial and interlaminar shear strength. Importantly, CNTs/CF650 obtains a high-performance EMW absorption ability with a minimum reflection loss (RL min) of −56.11 dB at 7.36 GHz, and delivers an effective absorption band (EAB) of 3.6 GHz at an ultrathin thickness of 1.18 mm. Notably, CNTs/CF700 exhibits the widest EAB (4.2 GHz) at merely 1.35 mm, basically covering the entire Ku-band. The superior RL min and boosted EAB stem from the synergistic effects of multiple heterointerfaces, enriched defects, proper electronic conductivity, and rational impedance matching. Therefore, the work demonstrates a facile and efficient strategy to develop strong EMW absorbers based on CF with light weight, thin thickness, and high strength. [Display omitted] [ABSTRACT FROM AUTHOR]

MXenes have been attracting enormous attention owning to their high electronic conductivity, abundant functional groups, and surface modification ability in the application of electromagnetic interference (EMI) shielding. In this work, TiO 2 nanoparticles were in-situ grown on the surface of crumpled Ti 3 C 2 T x MXene to generate TiO 2 /MXene heterointerfaces and create an extra absorption path. It was found that Ti 3 C 2 T x with less oxidation time generated more TiO 2. This intriguing phenomenon was caused by the fact that more functional groups escaped in the pre-oxidation step, creating extra active sites and allowing for more intense oxidation in a shorter period. Besides, the hybrid showed negative permittivity due to the metal-like conduction behavior, contributing to the reflection-dominant shielding mechanism. The TiO 2 /MXene heterostructure with negative permittivity exhibited an excellent total EMI shielding effectiveness of 73.98 dB at a filler content of 25 wt% in 8.0–12.4 GHz (covering the X band) at 2 mm. This work offers a new insight into exploring the structure-property relationship for MXene-based materials. [ABSTRACT FROM AUTHOR]

• A fundamental framework consisting of the IFDS-based path planning module and the BLADRC-based path tracking module is developed. • A long short-term memory (LSTM)-based fast online decision-making network matched with the IFDS is designed. • The trained LSTM network can quickly provide the optimal coefficients for the IFDS. • The dynamic characteristics of the 6-DOF UAV model and the performance of the inner controller are considered in the planning phase so that the planned path has high feasibility. • The proposed method is competent for 3D static and dynamic environments with high real-time performance, and planned path has high quality and feasibility. Path planning is crucial for achieving autonomous and safe flight of fixed-wing unmanned aerial vehicles (UAVs). The existing methods generally cannot simultaneously balance real-time performance, near optimality, and feasibility in three-dimensional obstacle environments. To this end, this paper proposes a deep learning-based integrated path planning and tracking control framework for obstacle avoidance. First, a fundamental framework, including an interfered fluid dynamical system (IFDS)-based path planning module and a backstepping control-based path tracking module, is established. Then, to satisfy high real-time requirements, a long short-term memory (LSTM)-based fast online decision-making network matched with the IFDS is developed. Extensive training samples are generated by the fundamental framework, and receding horizon control is employed to optimize these samples so that the LSTM can provide near-optimal coefficients for the IFDS. Furthermore, the dynamic characteristics of an actual UAV system and the performance of the tracking controller are fully considered during sample generation, enabling that the paths planned by the LSTM-assisted IFDS are highly feasible. Finally, the results of numerical simulations and hardware-in-the-loop experiments show that our method can plan near-optimal obstacle-free paths with high feasibility in real-time. [ABSTRACT FROM AUTHOR]

MXenes have been utilized to fabricate electromagnetic wave (EMW) absorbers owning to large aspect ratio, high electronic conductivity, and favorable hydrophilicity. In this work, the core-shell MXene/nitrogen-doped (N-doped) C heterostructure was firstly prepared via HCl and LiF etching, in-situ polymerization, and carbonization. When mixed with paraffin at a low filler loading of 30 wt%, the MXene/N-doped C hybrid reached a wide effective absorption bandwidth of 5.0 GHz (13.0 GHz–18.0 GHz) at a thin thickness of 1.72 mm. The stronger ability of attenuating EMWs promoted the absorption performance of MXene/N-doped C, overcoming the deficiency in the characteristics of impedance compared with its counterparts. This work provides a new insight in manufacturing MXene-based absorbers to alleviate EMW pollution by delicate structural design and effective multi-component strategy. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs)/carbon fiber (CF) reinforcements were prepared by chemical vapor deposition after electrochemical anodization and catalyst impregnation. The results showed that after the electrochemical anodization, the CFs were oxidatively etched and the surface roughness increased, which is helpful to form a uniform catalyst coating on the surface of CF. Under the current of 0.4 A and 0.6 A, CNTs can grow evenly on the surface of CF. Within a certain range, with the increase of growth time, the density and length of CNTs are improved. The CNTs/CF reinforcement prepared at the current intensity of 0.4 A and the growth time of 8 min has the best comprehensive performances compared with other as-fabricated samples. The tensile strength of the sample can reach a high value of 4.56 GPa, and the wettability of resin has an effective improvement. [ABSTRACT FROM AUTHOR]

Reversible data hiding in encrypted images (RDH-EIs) has attracted increasing attention since it can protect the privacy of original images while exactly extracting the embedded data. In this paper, we propose an RDH-EI scheme with multiple data hiders. First, we introduce a cipher-feedback secret sharing (CFSS) technique using the cipher-feedback strategy of the Advanced Encryption Standard. Then, using the CFSS technique, we devise a new $(r,n)$ -threshold ($r\leq n$) RDH-EI scheme with multiple data hiders called CFSS-RDHEI. It can encrypt an original image into $n$ encrypted images with reduced size using an encryption key and sends each encrypted image to one data hider. Each data hider can independently embed secret data into the encrypted image to obtain a marked encrypted image. The embedded data can be extracted from each marked encrypted image using the data hiding key, and the original image can be completely recovered from $r$ marked encrypted images using the encryption key. Performance evaluations show that our CFSS-RDHEI scheme has a higher embedding rate and that its generated encrypted images are much smaller, while still being well protected, compared to existing secret sharing-based RDH-EI schemes. [ABSTRACT FROM AUTHOR]

Dynamic vision sensors (event cameras) have recently been introduced to solve a number of different vision tasks such as object recognition, activities recognition, tracking, etc. Compared with the traditional RGB sensors, the event cameras have many unique advantages such as ultra low resources consumption, high temporal resolution and much larger dynamic range. However, these cameras only produce noisy and asynchronous events of intensity changes, i.e., event-streams rather than frames, where conventional computer vision algorithms can't be directly applied. In our opinion the key challenge for improving the performance of event cameras in vision tasks is finding the appropriate representations of the event-streams so that cutting-edge learning approaches can be applied to fully uncover the spatio-temporal information contained in the event-streams. In this paper, we focus on the event-based human gait identification task and investigate the possible representations of the event-streams when deep neural networks are applied as the classifier. We propose new event-based gait recognition approaches basing on two different representations of the event-stream, i.e., graph and image-like representations, and use graph-based convolutional network (GCN) and convolutional neural networks (CNN) respectively to recognize gait from the event-streams. The two approaches are termed as EV-Gait-3DGraph and EV-Gait-IMG. To evaluate the performance of the proposed approaches, we collect two event-based gait datasets, one from real-world experiments and the other by converting the publicly available RGB gait recognition benchmark CASIA-B. Extensive experiments show that EV-Gait-3DGraph achieves significantly higher recognition accuracy than other competing methods when sufficient training samples are available. However, EV-Gait-IMG converges more quickly than graph-based approaches while training and shows good accuracy with only few number of training samples (less than ten). So image-like presentation is preferable when the amount of training data is limited. [ABSTRACT FROM AUTHOR]

Apple rubbery wood virus 2 (ARWV-2) and citrus virus A (CiVA) belong to a recently approved family Phenuiviridae in the order Bunyavirales and possess negative-sense single-stranded RNA genomes. In this study, the genome sequence of three ARWV-2 isolates (S17E2, LYC2, and LYXS) and a CiVA isolate (CiVA-P) infecting pear trees grown in China were characterized using high-throughput sequencing combined with conventional reverse-transcription PCR (RT-PCR) assays. The genome-wide nt sequence identities were above 93.6% among the ARWV-2 isolates and above 93% among CiVA isolates. Sequence comparisons showed that sequence diversity occurred in the 5′ untranslated region of the ARWV-2 genome and the intergenic region of the CiVA genome. For the first time, this study revealed that ARWV-2 proteins Ma and Mb displayed a plasmodesma subcellular localization, and the MP of CiVA locates in cell periphery and can interact with the viral NP in bimolecular fluorescence complementation assays. RT-PCR tests disclosed that ARWV-2 widely occurs, while CiVA has a low incidence in pear trees grown in China. This study presents the first complete genome sequences and incidences of ARWV-2 and CiVA from pear trees and the obtained results extend our knowledge of the viral pathogens of pear grown in China. [ABSTRACT FROM AUTHOR]

The potential of two-dimensional layered MXenes in electromagnetic wave (EMW) absorption needs further development. Herein, we carried out the in situ growth of carbon nanotubes (CNTs) on the surface of Ti 3 C 2 T x MXene at ultra-low temperature via chemical vapor deposition. The obtained CNTs exhibited a bamboo-like structure and were accompanied by helical carbon nanofibers. The ultra-low temperature solved the problem that the high temperature required in the traditional CNT growth process would destroy the structural integrity of MXene. The lush CNT forest cross-linked the MXene layers, transforming the two-dimensional layered structure into a three-dimensional conductive network, providing abundant conductive channels for carriers, optimizing the impedance matching of the CNT/MXene hybrid, and resulting in a significant dielectric loss. The as-prepared CNT/MXene hybrid exhibited a minimal reflection loss of −52.56 dB (99.9994% EMW absorption) in the X-band. This work proposes a new idea to enhance the EMW absorption properties of Ti 3 C 2 T x MXene and fabricate high-performance MXene-based EMW absorbers. [ABSTRACT FROM AUTHOR]

As electromagnetic wave (EMW) pollution has become a serious problem in daily life, lightweight, efficient, and mass-produced EMW-absorbing materials are urgently needed. Herein, we developed a novel method for the continuous growth of carbon nanotubes (CNTs) on the surface of polyacrylonitrile (PAN)-based carbon fibers (CFs) by chemical vapor deposition (CVD), which can be applied to mass production. The obtained CF/CNT composites demonstrate outstanding EMW absorption capability, exhibiting a -58.75 dB reflection loss (RL) at a thickness of 1.54 mm. An effective absorption bandwidth (RL < -10 dB) of 4.24 GHz (13.76–18.00 GHz) was achieved at a thickness as low as 1.25 mm, which almost covers the entire Ku band. The excellent EMW-absorbing performance can be attributed to the 3D conductive network constructed by the CNT forest, which effectively promotes multiple reflections and scattering, and further favors dipole and interface polarizations. The mechanical properties of CF, CF-electrochemical anodic oxidation (EAO), and CF/CNT composites were examined, the results showed that the single-filament tensile strength of CF/CNT@0.07 and CF/CNT@0.09 was effectively improved. Our work suggests that the novel CF/CNT composite is a promising material for EMW absorption and strength enhancement owing to its light weight, high strength, low thickness, and good scale-up ability. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel cytorhabdovirus, tentatively named Actinidia virus D (AcVD), was identified from kiwifruit (Actinidia chinensis) in China using high‐throughput sequencing technology. The genome of AcVD consists of 13,589 nucleotides and is organized into seven open reading frames (ORFs) in its antisense strand, coding for proteins in the order N‐P‐P3‐M‐G‐P6‐L. The ORFs were flanked by a 3′ leader sequence and a 5′ trailer sequence and are separated by conserved intergenic junctions. The genome sequence of AcVD was 44.6%–51.5% identical to those of reported cytorhabdoviruses. The proteins encoded by AcVD shared the highest sequence identities, ranging from 27.3% (P6) to 44.5% (L), with the respective proteins encoded by reported cytorhabdoviruses. Phylogenetic analysis revealed that AcVD clustered together with the cytorhabdovirus Wuhan insect virus 4. The subcellular locations of the viral proteins N, P, P3, M, G, and P6 in epidermal cells of Nicotiana benthamiana leaves were determined. The M protein of AcVD uniquely formed filament structures and was associated with microtubules. Bimolecular fluorescence complementation assays showed that three proteins, N, P, and M, self‐interact, protein N plays a role in the formation of cytoplasm viroplasm, and protein M recruits N, P, P3, and G to microtubules. In addition, numerous paired proteins interact in the nucleus. This study presents the first evidence of a cytorhabdovirus infecting kiwifruit plants and full location and interaction maps to gain insight into viral protein functions. [ABSTRACT FROM AUTHOR]

This article provides a method for growing carbon nanotubes(CNTs) on carbon fibers(CFs) using iron and nickel as catalysts at low temperatures. This series of experiments was conducted in a vacuum chemical vapor deposition(CVD)furnace. It is found that Fe–Ni catalysts, which have a certain thickness and can be better combined with resins when manufacturing composite materials, are more ideal for the growth of CNTs than single metal catalysts. At the same time, it is proved that the CVD process worked best at 450 °C. The mechanical property test proved the reinforcing effect of CNTs on carbon fiber, the single-filament tensile strength of CFs obtained by using Fe–Ni catalyst at 450 °C was 11% higher than that of Desized CFs. The bonding strength of carbon fiber and resin has also been significantly improved. When synthesized at low temperature, CNTs exhibited a hollow multi-wall structure. [ABSTRACT FROM AUTHOR]

Graphene (GN) is transformed into carboxylic graphene (GO-COOH) with carboxylic groups by acidizing. Carboxylic graphene/polyimide (GO-COOH/PI) composite films are prepared by in-situ polymerization. The composite films show strong intermolecular force compared to the PI films which leads to excellent tensile strength and thermal conductivity. The composite films can be transformed into carbon films and graphite films by carbonization and graphitization. The GO-COOH can induce the graphitization process and compensate the defects. The thermal conductivity of graphite films prepared by composite films graphitized at the same temperature is higher compared to that of PI films. The addition of GO-COOH has great effects on reducing carbonization and graphitization temperature and improving property of films. The graphite films treated with 2500 °C possess smoother surface and the color of graphite films turn into dark grey. The films can keep the integral state and bend to a certain extent which exhibits that the flexibility of the graphite films is improved. The thermal conductivity of graphite films prepared by composite films treated with 2500 °C is 760.386 W/mK and increases by 128% compared to that prepared by the PI films, which is suitable for the application of heat conduction. [ABSTRACT FROM AUTHOR]

Carbon films prepared by polyimide (PI) films treated under 1500°C exhibit favorable thermal conductivity. However, the bonds of carbon films will fracture and recombine which will cause shrinking and forming defects. The flexibility of the carbon films will be greatly reduced, and then affect the application of the carbon films in the field of thermal conduction. When the films prepared by the graphene oxide/polyimide (GO/PI) composite films and the reduced graphene oxide/polyimide (rGO/PI) composite films, respectively, rGO and GO can fill the defects, then increasing the flexibility of the carbon films and inducing the carbonation process. Because of the high thermal conductivity and the six-membered ring structure of rGO and GO, the carbonization temperature will decrease and save costs. When the composite films treated under 1500°C, the thermal conductivity increases with the content of rGO and GO. There are connections between PI and graphene. As the amount of rGO and GO increases, the strong interactions between the rGO or GO and PI lead to contact that enhances its thermal conductivity. However, the rGO and GO have different effects on the films flexibility and thermal conductivity and the differences will be described in the article. [ABSTRACT FROM AUTHOR]

Exploring carbon materials is promising for innovative electromagnetic wave (EMW) absorption materials, nevertheless challenged by balancing efficient EMW absorption and continuous large-scale fabrication. In this work, CNTs/CNFs@CF with inimitable 3D network hierarchical structures are fabricated as EMW absorbers via the chemical vapor deposition method. Through detailed characterization of its morphology, structure, composition, and magnetic properties, the material obtained optimal electromagnetism parameters and showed exceptional EMW absorption performance. Herein, the minimum reflection loss (RL min) was −66.00 dB at 1.00 mm and the maximum effective absorption bandwidth of 4.48 GHz was obtained at 1.29 mm. In addition, good mechanical properties with a single-filament tensile strength of 4.99 GPa were achieved, thereby expanding the range of applications. Undoubtedly, CNTs/CNFs@CF realizes the synergy of multiple synergistic loss mechanisms and impedance matching for EMW absorption. In summary, this implies a good prospect for the continuous large-scale preparation of ultrathin and efficient EMW absorbers. • CNTs/CNFs@CF with 3D network hierarchical structures are fabricated for facile synthesis. • The synergistic effect of impedance matching and strong attenuation is realized. • Combined with excellent mechanical properties, expanding the range of applications. [ABSTRACT FROM AUTHOR]

This paper provides a continuous method for grafting carbon nanotubes (CNTs) on the surface of carbon fibers by chemical vapor deposition (CVD). The control of the morphology of CNTs/CFs can be achieved by adding thiourea to the cobalt nitrate precursor. The sulfur can increase the catalytic activity of the Co catalyst. Scanning electron microscopy reveals that a uniform layer of CNTs is grafted onto the surface of carbon fibers with the presence of thiourea. Through the single-filament tensile strength test, it can be found that the tensile strength of the fiber is increased by up to about 10% compared with the desized carbon fibers after the CVD process. And the reason for the enhancement is explored through X-ray diffraction. Raman spectroscopy reveals that the sample possesses the highest degree of graphitization at a thiourea concentration of 0.02 mol/L. It is found by high-resolution transmission electron microscopy that the growth mechanism of CNTs is tip growth mechanism, and the diameter of the CNTs is about 15 nm. [ABSTRACT FROM AUTHOR]

Turbostratic boron nitride (t-BN) coatings were successfully synthesized on the surface of carbon fibers by dip-coating method. Boric acid and urea were used as boron source and nitrogen source separately and the nitridation process was carried out at 850°C for 4h under the protection of N2. Dipping times were considered as variables to find out optimum amounts. The structure, chemical composition, phase and properties of BN coated carbon fibers were characterized. Results showed that continuous and uniform coatings were prepared after three times dipping and adhered well with carbon fibers. The coatings were mainly composed of the phase of t-BN. The oxidation property and high temperature resistant performance of the BN modified carbon fibers were greatly improved. [ABSTRACT FROM AUTHOR]

The introduction of a symmetry‐ and size‐matching pore‐partitioning agent in the form of either a molecular ligand, such as 2,4,6‐tri(4‐pyridinyl)‐1,3,5‐triazine (tpt), or a metal‐complex cluster, into the hexagonal channels of MIL‐88/MOF‐235‐type (the acs net) to create pacs‐type (partitioned acs) crystalline porous materials is an effective strategy to develop high‐performance gas adsorbents. We have developed an integrated COF–MOF coassembly strategy as a new method for pore‐space partitioning through the coassembly of [(M3(OH)1−x(O)x(COO)6] MOF‐type and [B3O3(py)3] COF‐type trimers. With this strategy, the coordination‐driven assembly of the acs framework occurred concurrently and synergistically with the COF‐1‐type condensation of pyridine‐4‐boronic acid into a C3‐symmetric trimeric boroxine molecule. The resulting boroxine‐based pacs materials exhibited dramatically enhanced gas‐sorption properties as compared to nonpartitioned acs‐type materials and are among the most efficient NH3‐sorption materials. [ABSTRACT FROM AUTHOR]

The introduction of a symmetry‐ and size‐matching pore‐partitioning agent in the form of either a molecular ligand, such as 2,4,6‐tri(4‐pyridinyl)‐1,3,5‐triazine (tpt), or a metal‐complex cluster, into the hexagonal channels of MIL‐88/MOF‐235‐type (the acs net) to create pacs‐type (partitioned acs) crystalline porous materials is an effective strategy to develop high‐performance gas adsorbents. We have developed an integrated COF–MOF coassembly strategy as a new method for pore‐space partitioning through the coassembly of [(M3(OH)1−x(O)x(COO)6] MOF‐type and [B3O3(py)3] COF‐type trimers. With this strategy, the coordination‐driven assembly of the acs framework occurred concurrently and synergistically with the COF‐1‐type condensation of pyridine‐4‐boronic acid into a C3‐symmetric trimeric boroxine molecule. The resulting boroxine‐based pacs materials exhibited dramatically enhanced gas‐sorption properties as compared to nonpartitioned acs‐type materials and are among the most efficient NH3‐sorption materials. [ABSTRACT FROM AUTHOR]

Based on MnO2/carbon cloth (CC) composite materials, an Ag-doped MnO2 nanowire, self-assembled, urchin-like structure was synthesized in situ on the surface of CC using a simple method, and a novel and efficient flexible electrode material for supercapacitors was developed. The morphology, structure, elemental distribution, and pore distribution of the material were analyzed using SEM, TEM, XRD, XPS, and BET. The electrochemical performance was tested using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). In the three-electrode system, GCD testing showed that the specific capacitance of the material reached 520.8 F/g at 0.5 A/g. After 2000 cycles at a current density of 1 A/g, the capacitance retention rate was 90.6%, demonstrating its enormous potential in the application of supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

A novel process has been successfully developed to grow carbon nanotubes (CNTs) on continuously moving carbon fibers (CF) surface by a unique open-ended chemical vapor deposition (CVD) furnace. Systematic researches were carried out under various deposition temperatures, velocities of continuous carbon fibers and catalyst concentrations. The morphologies and structures of CNTs were investigated by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM), which indicated clearly that carbon fibers with uniformly distributed CNTs were achieved, with the optimum parameters of 650 °C deposition temperature and 6 cm min −1 velocity of continuous carbon fibers and 0.05 M catalyst concentration, respectively. By means of the single fiber push-out tests, the interfacial shear strength (IFSS) of carbon fibers growing CNTs was increased significantly by 84.4% compared to the desized carbon fibers. Furthermore, the results of single fiber tensile test verified that there is scarcely any degradation in the mechanical properties of carbon fibers after the growth of CNTs with the optimum parameters. This study provides a new and original vision for scalable manufacturing of CNTs on continuous moving substrate, when compared to the traditional batch process. [ABSTRACT FROM AUTHOR]

The rapid development of organometal halide perovskite solar cells (PSCs) has led to reports of power conversion efficiencies of over 22%. TiO 2 is the most commonly used material for the electron transport layer in PSCs. ZnO is an excellent inorganic semiconductor material owing to its large surface area, easy synthesis, direct electron pathways, large variety of synthesizable nanostructures, and low cost of fabrication. It can potentially replace TiO 2 as the electron transport layer material in high efficiency perovskite solar cells based on flexible substrates. However, the number of reported high performance PSCs using ZnO nanostructures is still limited. This review focuses on the recent developments in the application of ZnO nanostructures in PSCs. The current state-of-the-art techniques and the open questions in the area of ZnO-based PSCs are also highlighted. Finally, we present a brief analysis on the opportunities and challenges for the use of ZnO in PSCs. [ABSTRACT FROM AUTHOR]

The compass rose is one of the few “recurring patterns” found in financial markets. In this paper, the compass rose in Chinese A-share market is comprehensively investigated. It is newly discovered that among the 1331 A-shares, which had been listed for more than 15 years by the end of 2015, only about 20 show the compass rose. The outcome of the analysis shows that there exists a threshold of the ratio of the data points on main rays to all data points. Only when this ratio is above the threshold, the compass rose appears. The reasons why such a threshold exists, and its interrelationship with the data frequency and the tick/volatility ratio are analyzed. [ABSTRACT FROM AUTHOR]

Apple stem grooving virus(ASGV) is the type species of the genusCapillovirusin the familyBetaflexiviridae. The virus naturally infects several important horticultural crops. Although many ASGV isolates from apple (Malusspp.), pear (Pyrusspp.), citrus (Citrusspp.) and lily (Liliumspp.) have been characterized, the occurrence status and molecular characteristics of the virus from kiwifruit trees are still largely unknown. In this study, by employing the strategy of small RNA deep sequencing coupled with conventional RT-PCR, we provide the first complete genome sequence of an ASGV isolate (named ASGV-Ac) infecting a kiwifruit plant (Actinidia chinensis) grown in China. The complete genome of ASGV-Ac consisted of 6496 nucleotides, excluding poly (A) tail at its 3ʹ end. ASGV-Ac shared high nucleotide sequence identities of 96.9% and 93.5% with a kiwifruit ASGV isolate reported from New Zealand (accession no. AF522459) for their CP and MP coding regions. However, the isolate was phylogenetically distal to ASGV isolates from all other hosts by sharing 79.5–82.4% genome sequence identity, and likely represented a novel variant. RT-PCR detection revealed the presence of ASGV-infected kiwifruit in two provinces in China. The partial CP gene of nine ASGV isolates determined in this study shared 87.8–99.6% nucleotide sequence identity with the corresponding sequences of other reported ASGV isolates from kiwifruit, indicating molecular diversity of ASGV isolates from kiwifruit plants. This study provides important evidence for monitoring the viral disease and novel molecular information for developing efficient detection techniques to prevent virus spread. Le virus du bois strié du pommier (VBSP) est l’espèce type du genreCapillovirusde la famille desBetaflexiviridae. Le virus infecte naturellement diverses cultures horticoles d’importance. Bien que plusieurs isolats de VBSP collectés sur les pommiers (Malusspp.), les poiriers (Pyrusspp.), les citrus (Citrusspp.) et les lis (Liliumspp.) aient été caractérisés, les caractéristiques moléculaires et le degré d’occurrence du virus chez le kiwi sont presque totalement inconnus. Dans cette étude, à l’aide du séquençage en profondeur des petits ARN, combiné à une RT-PCR classique, nous fournissons la première séquence génomique complète d’un isolat de VBSP (nommé VBSP-Ac) infectant un plant de kiwi (Actinidia chinensis) cultivé en Chine. Le génome complet de VBSP-Ac était constitué de 6 496 nucléotides, à l’exclusion de la queue poly (A) de l’extrémité 3ʹ. Le VBSP-Ac partageait de fortes identités de séquences de nucléotides de 96.9% et de 93.5% avec un isolat de VBSP de kiwi de Nouvelle-Zélande (n° d’accession AF522459) quant à leurs régions codantes CP et MP. Toutefois, l’isolat était phylogénétiquement distal quant aux isolats de VBSP provenant de tous les autres hôtes, et ce, en partageant de 79.5 à 82.4% de l’identité de la séquence du génome, représentant de toute évidence une nouvelle variante. La détection par RT-PCR a révélé l’occurrence de kiwis infectés par le VBSP dans deux provinces de Chine. Le gène partiel CP de neuf isolats de VBSP identifiés dans le cadre de cette étude partageait de 87.8 à 99.6% de l’identité de la séquence des nucléotides avec les séquences correspondantes d’autres isolats connus de VBSP provenant de kiwis, ce qui met en évidence la diversité moléculaire des isolats de VBSP provenant des plants de kiwi. Cette étude fournit suffisamment de preuves pour inciter à suivre l’évolution de cette maladie virale et amplement d’information moléculaire novatrice pour développer des techniques de détection efficaces visant à prévenir la dissémination du virus. [ABSTRACT FROM AUTHOR]

As a new member of the two-dimensional material family, Ti 3 C 2 T x MXenes have gained considerable attention for electromagnetic wave absorption applications. Herein, a graphite-ring-stacked carbon nanotube (CNT)/Ti 3 C 2 T x MXene composite with a three-dimensional network structure was fabricated via a vacuum freeze-drying process followed by a vacuum in situ growth at ultra-low temperatures. The well-designed process effectively protects the MXene structure from being damaged by high temperatures and prevents its oxidation. To the best of our knowledge, this study is the first to report on graphite-ring-stacked CNTs. The obtained CNT/MXene composite exhibited a minimal reflection loss of − 47.28 dB and an effective absorption bandwidth of 4.16 GHz at low sample thicknesses of 1.36 and 1.16 mm, respectively. Moreover, owing to its strong polarization and interference-type loss, the CNT/MXene composite exhibited unique impedance matching and reflection loss curves with dual-peak characteristics, which effectively broadened its absorption bandwidth. This work provides insights into MXene-based electromagnetic wave absorbers with enhanced absorption properties through microstructure design and multi-component synthesis strategies. [Display omitted] • Ultra-low temperature to prevent MXene from structural damage and oxidation. • Unique concentric-ring-like graphite layer stacked CNTs with defects. • Interesting dual-peak absorption phenomenon. [ABSTRACT FROM AUTHOR]

Silk nanofibers (SNF) have great applications in high-performance functional nanocomposites due to their excellent mechanical properties, biocompatibility, and degradability. However, the preparation of SNF by traditional methods often requires the use of some environmentally harmful or toxic reagents, limiting its application in green chemistry. In this paper, we successfully prepared SNF using natural silk as raw material and solvent stripping technology by adjusting the solvent concentration and solution ratio (the diameter of about 120 nm). Using the above SNFs as raw materials, SNF membranes were prepared by vacuum filtration technology. In addition, we prepared an SNF/MXene nanocomposite material with excellent humidity sensitivity by simply coating MXene nanosheets with silk fibers. The conductivity of the material can approach 1400.6 S m−1 with excellent mechanical strength (51.34 MPa). The SNF/MXene nanocomposite material with high mechanical properties, high conductivity, and green degradability can be potentially applied in the field of electromagnetic interference (EMI) shielding, providing a feasible approach for the development of functional nanocomposite materials. [ABSTRACT FROM AUTHOR]

The carbon materials, as one of the Pt-free alternative materials, have been extensively used for the counter electrodes of dye-sensitized solar cells. In this study, a series of functionalized graphenes with doping N or/and S atoms in different configurations are investigated with density functional theory to reveal their different electrocatalytic activity in the process of I 2 adsorption. The results show that the adsorption energy and the transferred charge between the substrate and adsorbed I 2 on the surface of N/S co-doped graphene are much bigger than that of N or S monodoped graphene. The enhanced adsorption activity of the former essentially results from the synergistic effect by co-doping with N and S atoms in promoting the positive charge density distribution of active centers and increasing the number of active sites. It is also found that the charge and spin distributions features are two reliable benchmarks for evaluating the physical or chemical adsorption activity of materials and guiding the design of high-performance counter electrodes materials for dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

An innovative technique has been developed to obtain the uniform catalyst coating on continuously moving carbon fibers. Carbon nanotube (CNT)-grafted carbon fibers with significantly improved tensile strength have been succeeded to produce by using chemical vapor deposition (CVD) when compared to the tensile strength of untreated carbon fibers. The critical requirements for preparation of CNT-grafted carbon fibers with high tensile strength have been found, mainly including (i) the obtainment of uniform coating of catalyst particles with small particle size, (ii) the low catalyst-induced and mechano-chemical degradation of carbon fibers, and (iii) the high catalyst activity which could facilitate the healing and strengthening of carbon fibers during the growth of CNTs. The optimum growth temperature was found to be about 500 °C, and the optimum catalyst is Ni due to its highest activity, there is a pronounced increase of 10% in tensile strength of carbon fibers after CNT growth at 500 °C by using Ni catalyst. Based on the observation from HRTEM images, a healing and crosslink model of neighboring carbon crystals by CNTs has been formulated to reveal the main reason that causes an increase in tensile strength of carbon fibers after the growth of CNTs. Such results have provided the theoretical and experimental foundation for the large-scale preparation of CNT-grafted carbon fibers with the improved tensile strength, significantly promoting the development of CNT-grafted carbon fiber reinforced polymer composites. [ABSTRACT FROM AUTHOR]

Abstract: This note describes a fundamental investigation into solid-phase microextraction (SPME) using a standard loaded into the fibre coating as a means of internal standardisation for the analysis of samples contained in vials. The loading of reproducible amounts of standards into a non-porous SPME fiber was investigated. It was found that spiking low milligram quantities of standards such as benzene, toluene, ethylbenzene, xylenes (BTEX) and/or naphthalene into a few grams of pump oil sealed in a 20mL vial provided an excellent standard generator. A single solution allowed over a hundred standard loadings with a reproducibility of &#60;4% R.S.D. When a fiber, loaded with the standard(s) was introduced into a sample vial, extraction of analytes into the fiber and desorption of the standard(s) into the sample matrix occur simultaneously. Quantification was then based on the equilibrium distribution of the standards and the analytes between the fibre coating and the sample matrix in the vial. A comparison of equilibration profiles obtained using traditional internal standardisation and the in-fibre approach generally showed the same equilibration behaviour. The developed method was successfully used to correct for matrix effects in the BTEX analysis of a wine sample. [Copyright &y& Elsevier]

The effect of porous carbon preform and the infiltration process on the properties of reaction-formed SiC have been investigated in this paper. Five different porous carbon preforms with porosity in a range 35–67% and pore size from 0.03 to 2.58 μm have been infiltrated with liquid or vapor Si. The porous carbon preform and infiltration process affect the reaction rate and infiltration rate, which are key issues in designing the final reaction-formed silicon carbide microstructure. Under suitable experimental conditions, vapor infiltration can lead to deeper infiltration of Si than liquid infiltration. The best result has been obtained by vapor Si infiltration with a relatively smaller scale porous carbon preform having a density of 0.92 g cm-3. The reaction-formed silicon carbide with a flexural strength 630 MPa and density 3.12 g cm-3 and Si-content 8 vol.%, which is superior to commercially obtained reaction-bonded silicon carbides, have been fabricated by Si vapor infiltration. [Copyright &y& Elsevier]

This paper describes the production of shaped silicon carbide based ceramic materials by in situ reaction of silicon with fine, ultra-uniform porous carbon skeletons that were produced from liquid polymer solutions without any particulate additions. Three typical types of carbon preforms (spherical carbon particulates, crosslinked network carbon, and lamellate carbon particulates) were infiltrated with molten Si. The morphologies and mechanical properties of corresponding reaction-formed silicon carbide (RFSC) ceramics have been investigated. The results revealed that the RFSC obtained by molten Si reaction with the porous carbon preform with discrete and spherical carbon particulates has the most uniform microstructure, the highest flexural strength (410±30 MPa) and the lowest amount of residual Si (approximately 12 wt.%). The general feature of a fracture surface showed the typically brittle failure in those materials. [Copyright &y& Elsevier]

Wearable and bicontinuous Ag-doped poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate)/MnO 2 /carbon fabric was manufactured in a facile, eco-friendly, and scalable approach. The high temperature-resistant textile performed a maximum specific capacitance of 2.97 F cm−2, and delivered 113 % retention at 80 °C compared with that at room temperature. At a cooling-heating-cooling cycle, the capacitance could recover to its initial value after 10000 charge-discharge tests at 20 mA cm−2. Density function theory proves that Ag dopants and the S-containing functional group improve the adsorption ability with Na+. The maximum energy and power density achieved 19.36 mWh cm−3 and 530.50 mW cm−3 over a wide potential window of 2 V, respectively. Moreover, the fabric could be operated at low-temperature climates by multi-offset Joule heating performance and a deicing/dewatering ability. The antimicrobial capacity against typical bacteria and fungi renders robust safety to the wearable electronics. The fabric performed shielding effectiveness of 45.95 dB at 377 μm and reliable durability after 1000 times bending cycles. The reflection-dominant shielding mechanism was further revealed by COMSOL Multiphysics software. The all-in-one fabric complies with Internet of Things design and can endure extreme environments over a wide temperature range, implying great potential for energy storage, thermal management, bacteriostasis, and electromagnetic protection. [Display omitted] • Ag-doped PEDOT: PSS/MnO 2 /carbon fabric was designed in an eco-friendly approach. • The cloth displayed a high temperature-resistant electrochemical performance. • DFT simulation indicates the improved Na + affinity due to Ag dopants and S-containing functional groups. • The textile showed mechanical-tolerant electromagnetic interference shielding property. • COMSOL software shows the reflection-dominant shielding mechanism. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (RGO) is an ideal material as an electrode used in the electrochemical energy storage field. However, the serious aggregation of graphene sheets and fewer chemically active sites limit it from exhibiting higher performance. Herein, we introduce a facile solvothermal reaction method to simultaneously regulate the functional groups on RGO, balance the aggregation and connection of graphene sheets, and dope the nitrogen element in a graphene network. The obtained electrode (RGO-N(DMF)) has a high content of carbonyl and nitrogen functional groups, and shows a fluffy structure as well as good electron conductivity, exhibiting both high chemically and physically actives sites. Benefiting from these advantages, RGO-N(DMF) shows a high specific capacity of 135 mA h g−1 at 0.2 A g−1 and favorable rate performance of maintaining 53% capacity at 50 A g−1, which are both higher than those of the normal hydrothermally obtained RGO electrodes. More interestingly, RGO-N(DMF) can maintain the high electrochemical performance at a high mass loading of 5.1 mg cm−2. In addition, when the RGO-N(DMF) electrode is used in the flexible Zn-ion hybrid supercapacitor (ZHS), the capacity retention remains at 100% after 500-time bending, showing excellent mechanical flexibility. This study not only provides an effective strategy for constructing carbon-based cathode materials with excellent properties, but also provides prospects and enlightenment for the practical application of aqueous ZHSs. [ABSTRACT FROM AUTHOR]

Ni35 coatings were fabricated on 45 steel using a CO2 laser at various parameters. A relatively large spot (10 mm diameter) was adopted, which was beneficial to the coating quality and the cladding efficiency. The cross-sectional geometry, phase constituent, and microstructure of the coatings were investigated. With a lower specific energy, coating height increased, while coating width, melted depth, dilution rate, width to height ratio and contact angle decreased. Ni35 coating primarily consisted of γ-Ni, FeNi3, Ni3B, Cr23C6, and Cr5B3. Dendrites with flower-like, fishbone-like, pearl-like, and column-like morphologies were observed. The fraction of flower-like dendrites increased gradually with the decrease in scanning velocity due to the dendrite growth direction evolution. With the decrease in scanning velocity, the microstructure of the heat-affected zone transformed from martensite to martensite + sorbite and finally sorbite. The maximum microhardness of the Ni35 coating reached 451.8 HV0.2, which was about double that of the substrate (220 HV0.2). [ABSTRACT FROM AUTHOR]

Chinese jujube (Ziziphus jujuba Mill.) is a native fruit crop in China. Leaf mottle and dapple fruit disease is prevalent in cultivated jujube plants grown at Aksu in Xinjiang Uygur Autonomous Region of China. Jujube yellow mottle-associated virus (JYMaV), a tentative member in the genus Emaravirus, was recently identified from mottle-diseased jujube plants grown in Liaoning Province in China, but its incidence and genetic diversity in China is unknown. In this study, the genome sequences of three JYMaV isolates from two jujube cultivars and one jujube variant were determined by high-throughput sequencing (HTS) for small RNA and rRNA-depleted RNA coupled with RT-PCR assays. Comparison of these sequences together with sequences of the viral RNA segments derived by primer set 3C/5H-based RT-PCR revealed that genetic diversity was present in the virus populations and high sequence variation occurred at the non-translational regions of each of the viral genomic segments. Field investigation confirmed the close association of the virus with leaf mottle symptoms of jujube plants. Furthermore, this study revealed that P5 encoded in the viral RNA5 displayed a nuclear localization feature differing from the plasmodesma (PD) subcellular localization of the virus movement protein (P4), and the two proteins could interact with each other in the BiFC assays. Our study provides a snapshot of JYMaV genetic diversity in its natural hosts. [ABSTRACT FROM AUTHOR]

Porous boron nitride (p-BN) is gaining an enormous attention due to its application in gas absorption, photocatalysis, and drug delivery. However, complicated preparation steps and low specific surface area have been restricting its application. Detailed morphology and structure change and mechanism of pyrolysis process have never been discussed before. Therefore, the facile one-step pyrolysis method was introduced to fabricate the p-BN with high specific surface area. The results demonstrated that the as-synthesized samples with high purity was prepared at 1500 °C. Unpredictable outcome suggested that the pyrolysis temperature instead of precursor ratio has remarkable effects on samples. The structure changed from amorphous form into hexagonal layer and the morphology transformed from granular into flake when temperature varied from 1000 °C to 1500 °C. Its specific surface area and total pore volume reached to 1138.4 m2 g−1 and 0.7287 cm3 g−1, respectively. Explicit mechanism was investigated as well. And an intriguing phenomenon showed that the mass loss of as-prepared p-BN partly recovered at high temperature, which enclosed its unique thermal stability. Implications of the results suggest that this work proposed a facile route to prepare p-BN with high specific surface area. • Porous boron nitride can be fabricated by facile one-step pyrolysis method. • The pyrolysis temperature instead of precursor ratio affects the structure and morphology of the porous boron nitride. • The porous boron nitride shows colossal specific surface area, large absorption volume and intriguing thermal stability. [ABSTRACT FROM AUTHOR]

Abstract: ZnO nanosheets were obtained via a simple hydrothermal synthesis in the presence of sodium tripolyphosphate. The formation mechanism and effect of sodium tripolyphosphate concentration on the morphology of ZnO nanosheets have also been reported. Field emission scanning electron microscopy, transmission electron microscopy and fourier transform infrared spectroscopy were used to characterize the structure features and chemical compositions. The results show that the replacement of OH− dangling bond on ZnO positive polar faces (0001) by PO4 3− hinders splicing growth of [Zn(OH)4]2− growth units along the [0001] direction, which results in the formation of ZnO nanosheets. [Copyright &y& Elsevier]

A family of heterometallic metal-organic frameworks (MOFs) (CPM200s) harmoniously coexisting as Lewis acids and base (azo) sites were prepared. Seven CPM200s were employed as multifunctional heterogeneous cascade catalysts for the one-pot deacetalization-Knoevenagel reaction in a solvent-free system. Benefiting from the cooperation between Lewis acids from the open metal sites and base sites from the ligands, the CPM200s showed high activity and selectivity for the tandem reaction. The heterometallic 3D porous framework reported here not only offers a combination of two opposite active sites in the same framework of materials but also increases mass transfer of the substrate, thus maximizing the efficiency and substrate selectivity of the bifunctional catalysts. The CPM200s showed the highest turnover frequency (TOF), outperforming that of the reported MOFs in tandem with the deacetalization-Knoevenagel reaction. A strong correlation between the TOF and charge-to-radius ratio (z/r) of metal ions in the CPM200s was observed for the first time. The bifunctional CPM200s catalysts can be reused five times without significant loss of activity. [ABSTRACT FROM AUTHOR]

• A novel emaravirus was discovered in Actinidia spp. grown in China. • The virus had the closest phylogenetic relationships to FMV and PPSMV-2. • It was the second emaravirus infecting Actinidia trees. • Virus detection showed the presence of virus in three Actinidia species in China. Viruses in the genus Emaravirus contain 5–8 negative genomic RNAs and cause severe diseases of plants. In this study, a novel emaravirus, provisionally named Actinidia emaravirus 2 (AcEV-2), was identified from a kiwifruit tree showing leaf mottle and chlorosis symptoms. The genome of AcEV-2 consisted of at least six RNAs (RNAs 1–6) with sizes of 7079, 2252, 1387, 1514, 1744 and 1233 nucleotides (nts), respectively. Proteins encoded by RNAs1–4 of AcEV-2 shared the highest amino acid (aa) sequence identities of 62.2%–77.3% with the corresponding proteins of fig mosaic emaravirues (FMV) and pigeonpea sterility mosaic emaravirus 2 (PPSMV-2). Whilst, the P5 and P6 encoded by AcEV-2 exhibited the highest identities of 44.2% and 39.2% with the corresponding proteins of PPSMV-2. It was the second emaravirus infecting Actinidia trees in China. Preliminary virus detection disclosed the presence of AcEV-2 in three Actinidia species grown in three provinces in the central and southern China. [ABSTRACT FROM AUTHOR]

The carbon-doped silicon dioxide (C-doped SiO 2) coatings are prepared on the surface of carbon fibers by a facile sol-dipping method using tetraethoxysilane (TEOS) and diethoxydimethylsilane (DMDES) as precursors. The effect of heat treatment temperature and dipping times on the formation of the C-doped SiO 2 coatings is studied. The structure and morphology of C-doped SiO 2 coatings are analyzed by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The oxidation resistance of the carbon fibers with and without coatings is investigated by thermogravimetric analysis (TG) and static isothermal oxidation experiments. The results show that the C-doped SiO 2 products obtained by pyrolysis of the gel at 900 ℃ displays high crystallinity and low carbon content. The continuous and uniform coatings with the thickness about 200 nm are formed after three times dipping, which improves the initial oxidation temperature of carbon fibers about 110 ℃. [ABSTRACT FROM AUTHOR]

We report here a strategy for making anionic pacs type porous materials by combining pore space partition with charge reallocation. The method uses the first negatively charged pore partition ligand (2,5,8‐tri‐(4‐pyridyl)‐1,3,4,6,7,9‐hexaazaphenalene, H‐tph) that simultaneously enables pore partition and charge reallocation. Over two dozen anionic pacs materials have been made to demonstrate their excellent chemical stability and a high degree of tunability. Notably, Ni3‐bdt‐tph (bdt=1,4‐benzeneditetrazolate) exhibits month‐long water stability, while CoV‐bdt‐tph sets a new benchmark for C2H2 storage capacity under ambient conditions for ionic MOFs. In addition to tunable in‐framework modules, we show feasibility to tune the type and concentration of extra‐framework counter cations and their influence on both stability and capability to separate industrial C3H8/C3H6 and C6H6/C6H12 mixtures. [ABSTRACT FROM AUTHOR]

We report here a strategy for making anionic pacs type porous materials by combining pore space partition with charge reallocation. The method uses the first negatively charged pore partition ligand (2,5,8‐tri‐(4‐pyridyl)‐1,3,4,6,7,9‐hexaazaphenalene, H‐tph) that simultaneously enables pore partition and charge reallocation. Over two dozen anionic pacs materials have been made to demonstrate their excellent chemical stability and a high degree of tunability. Notably, Ni3‐bdt‐tph (bdt=1,4‐benzeneditetrazolate) exhibits month‐long water stability, while CoV‐bdt‐tph sets a new benchmark for C2H2 storage capacity under ambient conditions for ionic MOFs. In addition to tunable in‐framework modules, we show feasibility to tune the type and concentration of extra‐framework counter cations and their influence on both stability and capability to separate industrial C3H8/C3H6 and C6H6/C6H12 mixtures. [ABSTRACT FROM AUTHOR]

In order to improve the interfacial adhesion of epoxy composites, a hierarchical structure including carbon nanotubes (CNTs) grown on carbon fiber (CF) was prepared by a novel vacuum-assisted chemical vapor deposition (CVD) method at relatively low temperature of 400 °C under a pressure of 0.01 MPa. The short beam method and microbond test were used to measure the interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) of epoxy composites reinforced by different CFs. The results showed that the CNTs-grown CF prepared at the H2 flow rate of 9 L/min had the best reinforcement effect. The ILSS and IFSS of its composites were 19.50% and 62.32% higher than that of the CF/epoxy composites without CNTs grown, respectively. The improvement of interfacial adhesion can be attributed to the fact that CNTs inserted into the matrix enhanced the mechanical interlocking between the fiber and the resin and induced the formation of interphase. Also, two failure modes of CNTs have also been observed, which can absorb extra energy and increased the difficulty of the separation of fiber and resin. The increase in the glass transition temperature (Tg) indicated the movement of the polymer molecular chains at the interphase was restricted by CNTs, which also contributed to the improvement of the interfacial adhesion of composites. [ABSTRACT FROM AUTHOR]

Estimating clean seismic signals from noisy single‐channel records is a hot research topic in the field of microseismic data processing. Due to the existence of strong random noise, the signal‐to‐noise ratio of such data is low, presenting a challenge for signal restoration. In this paper, we propose a denoising method of microseismic data based on a single‐channel phase space reconstruction and independent component analysis algorithm. Specifically, we first apply the phase space reconstruction to transform the one‐dimensional seismic signal into a high‐dimensional phase space in which signal and noise have different trajectories. We then employ independent component analysis to the reconstructed data for noise separation. Experimental results on real microseismic data verify that our proposed denoising method is useful for noise suppression and can enhance the signal‐to‐noise ratio of data, which can be further used for signal identification and event positioning in microseismic monitoring. [ABSTRACT FROM AUTHOR]