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[Display omitted] • A phosphorus/nitrogen-containing hyperbranched epoxy resin (HPITT) was simply synthesized. • Both flame retardancy and toughness of epoxy thermosets were enhanced by HPITT. • EP/HPITT thermosets maintained excellent T g and T 5%. • HPITT was a prospective and versatile modifier for epoxy thermosets. Concurrently enhancing the flame retardancy and toughness without sacrificing strength, thermal decomposition temperature, and glass transition temperature (T g) of epoxy thermosets is still challenging. Herein, a new phosphorus/nitrogen-containing hyperbranched epoxy resin (HPITT) was synthesized from itaconic anhydride, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, piperazine, and triglycidyl isocyanurate by a facile method. The HPITT was then utilized for synergistic flame retarding and toughening modification of epoxy thermosets. Upon the introduction of 10 wt% HPITT, the epoxy thermosets reached a limiting oxygen index (LOI) of 31.5 % and UL-94 V-0 rating. Meanwhile, the peak heat release rate (PHRR) and total smoke production (TSP) decreased by 32.3 % and 27.7 % when compared to neat epoxy thermosets, respectively. Moreover, the synergistic flame retarding functions of phosphaphenanthrene, piperazine and isocyanurate segments in HPITT were demonstrated by combined gas and char phase residue analyses. Compared to neat epoxy, features such as the impact strength, tension strength, and flexural strength of the modified epoxy thermosets increased by respectively 53.9 %, 29.2 %, and 58 % owing to intramolecular cavities, rigid segments, and high crosslinking density supplied by HPITT. Moreover, the modified epoxy thermosets still maintained excellent T g and thermal decomposition temperature. In sum, an attractive strategy for concurrently enhancing flame retardancy and toughness of epoxy thermosets was proposed, useful for future advanced applications in adhesives, coatings, and composite materials. [ABSTRACT FROM AUTHOR]

Abstract: Furfural residues are by-products from the process of furfural production with corncobs. The cellulose in the residues can be used to produce ethanol, but lignin, the other main component in the residues, inevitably exerts unfavourable effects on the enzymatic hydrolysis process. In order to reveal the effects and make an efficient utilization of the lignin, the characteristics, especially the variation during furfural production, should first be investigated. In this paper, the milled wood lignin (MWL) of the furfural residual (FR) and corncob were separated and a comparative study of the MWL fractions was made in terms of the UV, FT-IR, 1H and 13C NMR spectra as well as the molecular weight and the thermal stability. It was found that the proportion of the three structure units in the two kinds of lignin fractions was different and that some reactions had taken place on the benzene rings during furfural manufacture. The methoxyls in the lignin structure units had been removed partially, and the groups conjugated with the benzene rings were destroyed. Moreover, the alcoholichydroxyl in the lignin of the corncob reduced and transformed into carbonyl. Both the degradation of the lignin and the condensation reactions have emerged during the furfural production. [Copyright &y& Elsevier]

Abstract: The objective of this work is to study the influence of complex manifold geometries on the flow distribution between microchannels by an analytical model and an equivalent electrical resistance network model. An optimization procedure is proposed to optimize the manifold geometries and dimensional variations to obtain comparatively ideal flow distribution between microchannels. A specific case is illustrated by applying the proposed optimization procedure to analyze the optimal rules for a given inlet distributing manifold geometry. Result shows that the microchannel width dominates the optimization of outlet collecting manifold geometry and dimensional variations. [Copyright &y& Elsevier]

• A method is proposed to imitate CO 2 sequestration in gas reservoirs with aquifer. • CO 2 -brine-rock interaction causes the change of formation properties inevitably. • The formation damage in gas zone is severer than that in water zone. • The negative impact on formation properties is minor in good-quality reservoir. • The strategy is offered to ensure CO 2 sequestration in gas reservoirs with aquifer. To understand the impact of CO 2 -brine-rock interaction on formation properties and the differences between gas zone and water zone, dynamic and static experiments were conducted under gas reservoir conditions to imitate the process of CO 2 injection and storage in gas reservoirs with aquifer. In this work, core plugs, rock debris and brine are taken from DF gas field, a giant gas reservoir with aquifer in the South Sea of China. Meanwhile, scan electron microscope (SEM), energy dispersive spectrum (EDS), X-ray diffraction (XRD) and flame atomic absorption spectrometry (FAAS) were also applied to analyze the mechanism of property alterations of brine and rock minerals due to CO 2 -brine-rock interaction. Results show that CO 2 -brine-rock interaction occurs in both gas zone and water zone since water evaporates into gas stream and CO 2 dissolves into brine to form carbonic acid. CO 2 -brine-rock interaction can cause rock minerals dissolution and to fall from the matrix to form free particles suspending in pore space filled with fluids and flow along with them. It generally triggers sharp reduction of formation permeability and leads to negative impact on CO 2 injectivity and storage. And the formation damage in gas zone is severer than that in water zone. Meanwhile, CO 2 -brine-rock interaction in good-quality reservoir in water zone can improve porosity and permeability to further enhance CO 2 injectivity and storage capacity. Thus, dry CO 2 should be preferentially injected into aquifer with good formation properties to weaken negative effect to ensure CO 2 successful injection and storage in gas reservoirs with aquifer. This work also provides a reference for designing technical scheme of CO 2 injection and storage in gas reservoirs with aquifer. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel fluorogenic RNA aptamer output sensor via in vitro transcription (IVT) activated by RPA (ROSAR) was developed. • The proposed ROSAR for pathogens nucleic acid (DNA or RNA) testing displayed outstanding performance. • A paper-based ROSAR was developed for improving the stability of reagents and facilitate POC testing. • An integrated, low-cost, and user-friendly device was designed for paper-based ROSAR readout using mobile phone. • The proposed ROSAR and paper-based ROSAR were validated using clinical samples, showed the potential of clinical application. Sensitive, simple, and rapid nucleic acid testing used for pathogen detection are crucial for preventing outbreaks and transmission of infectious diseases. In this study, we present a fluorogenic RNA aptamer Output Sensors via transcription Activated by Recombinase polymerase amplification (RPA), termed ROSAR, for highly sensitive detection of DNA and RNA from pathogenic bacteria or viruses in clinical samples. The promoter primer and reporter primer facilitate the integration of the transcriptional promoter with the fluorogenic RNA aptamer transcription templates through the RPA of target DNA. Subsequently, the amplification products are transcribed by T7 RNA polymerase, producing RNA aptamer that binds to a fluorogenic dye. The assay, which can be completed within 50 min and can allow a limit of detection of level aM nucleic acid concentration, owning to the dual amplification effects of RPA and in vitro transcription. Furthermore, we develop a paper-based ROSAR by freeze-drying the reaction components, which is compatible with visual detection based on mobile phone fluorescent reader and suitable for point-of-care (POC) applications. The assay can detect various viral and bacterial nucleic acids, making it a highly promising tool for large-scale epidemic screening and rapid POC testing in home healthcare settings. [ABSTRACT FROM AUTHOR]

• Stretchable triboelectric sensor array was proposed based on the coaxial printing. • Surface microstructures and output performance of TSA were studied. • TSA is a promising candidate for electronic skin and tactile detection. With the rapid development of flexible and wearable electronics, tactile sensor array has shown great potential to detect diverse external stimuli in human–machine interactions and robotic intelligence. In this study, we developed triboelectric sensor array (TSA) with cross-laminated electrode via low-cost coaxial printing technique with the advantages of high precision, high efficiency and excellent uniformity. The results show that the proposed cross-laminated electrode based TSA possesses the characteristics of easy-fabrication process, high-sensitivity, long-term mechanical endurance and real-time trajectory sensing capacity. It can generate the maximum output voltage of 15.98 V at a frequency 4 Hz and vertical force 5 N in single electrode mode, and the maximum power is about 3.9 μW. Besides, TSA shows excellent stability under harsh mechanical bending, twisting and stretching deformation and even waterproof capability. This work offers a previously unexplored strategy for shortening individual design and fabrication cycle of flexible electronics, and promoting the potential application for stretchable sensor array in electronic skin, tactile detection and human–machine interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Utilizing IRS effect to boost the PL energy outcoupling of perovskite phosphors. • A NMHS-LI reaction was developed to construct NP-PP structure inside the phosphors. • The NP-PP structure transformed the PL propagation from absorption mode to IRS mode. • Our NP-PP phosphor achieved an ultrahigh white luminous efficacy of 131.32 lm/W. Although stable perovskite phosphors, i.e., CsPbBr 3 /Cs 4 PbBr 6 , were extensively reported and made great progress, achieving strong photoluminescence (PL) energy outcoupling remains challenging owing to their short Stoke's shift with serious PL energy absorption. This study utilized internal resonant scattering (IRS) to improve the PL energy outcoupling (PEO) of CsPbBr 3 /Cs 4 PbBr 6 perovskite phosphor, which was realized by the nanopore-packing perovskite particles (NP-PPs) structure inside a phosphor. The nano-porous matrix hybrid solid–liquid interfacial reaction was developed to construct NP-PPs in a phosphor, and it is optimized to achieve a denser NP-PP structure with an enhanced PEO effect (2.8-fold enhanced PL intensity). Numerical results revealed that the NP-PP structure transforms the PL energy absorption mode to the IRS mode, most of the scattering PL energy evades NP-PPs instead of propagating inside. The optimized phosphor was applied to white devices, and we finally achieved an ultrahigh luminous efficacy of 131.32 lm/W based on green perovskite phosphors. This study provides a general guide for efficient perovskite phosphors utilizing the nano-porous matrix to enable the IRS effect. [ABSTRACT FROM AUTHOR]

• A planthopper gear-shaped flow channel for PEMFCs is developed. • The oxygen transport mechanism inside the GFCH-based PEMFC is revealed. • The effects of GFCHs for mitigating the oxygen starvation and boosting the reactant homogeneity in PEMFC are analyzed. • A PEMFC with an optimal GFCH with remarkable electrochemical performance is provided. The flow channel design of a proton exchange membrane fuel cell (PEMFC) is a key factor affecting the power output. This work proposes a planthopper gear-shaped flow channel (GFCH) to address the issues of oxygen starvation and reactant homogeneity in a PEMFC by strengthening oxygen transport from the flow channel to the electrode surface. Full-scale three-dimensional PEMFC based on the GFCHs is constructed to investigate and analyze the multi-phase mass transport process, flow velocity, pressure distribution and electrochemical performances, compared with the conventional serpentine flow channels (SFCHs). Results show that the GFCH remarkably boosts the oxygen transport to the electrode surface under the effects of bio-inspired strengthened structures. Due to the promoted mass transfer efficiency and reactant distribution homogeneity of the GFCHs, the peak power density of the optimized flow channel (1.04 W cm−2) is ∼ 46% higher than that of the conventional SFCH (0.71 W cm−2). The optimal structural parameters for the GFCH with 0.4 mm for the rib width and a combination of 0.6/0.4 mm for the channel height are obtained by simulation and experimental demonstration. We believe that using this novel channel shape provides a good solution for flow channel design of PEMFCs. [ABSTRACT FROM AUTHOR]

A catalytic micro-combustor using a pervaporation membrane as the passive methanol vaporizer is developed for direct methanol fuel cell (DMFC) applications, which is able to realize self-starting in an ambient environment. The methanol feed rate and the membrane diffusion coefficient related to the permeation flux are experimentally evaluated. Results indicate that the air feed rate (AFR) has positive effects on enhancing the methanol production and also increasing the catalyst temperature. A higher AFR promotes vapor generation and improves the combustion rate, thereby facilitating a higher start-up performance of the combustor. The infrared thermal analysis verifies the positive effect of increasing the AFR on the status of heat production and distribution. Results also validate the feasibility of changing the operating orientation of the combustor, which illuminates its potential use for portable applications. The online fuel cell tests validate that this combustor is viable to be used as a heat generator for a vapor-feed DMFC. [ABSTRACT FROM AUTHOR]

Highlights: [•] A catalytic micro-combustor is designed for methanol fuel cells. [•] The combustor uses Pt/Al2O3/Ni to provide catalysis for methanol combustion. [•] The effects of Pt and Al2O3 loadings and methanol feeding mode are evaluated. [•] The feasibility of self-combustion based on heat recirculation is validated. [Copyright &y& Elsevier]

Abstract: Velocity distribution among microchannel plays an important role in the performances of microchannel reactors. The optimization of structural parameters by enabling narrow uniform velocity distribution among microchannels is regarded as one of the effective design methods. On the basis of the previously developed model, the effects of structural parameters on the velocity distribution are studied and the relationship between frictional resistances and pressure drop are investigated in this work. It is found that the variation of pressure drop distribution among microchannels due to the variation of frictional resistances is the underlying reason for the variation of velocity distribution among microchannels. Compared with the manifold structural parameters, the microchannel structural parameters show more influence on the velocity distribution. High-aspect-ratio microchannels are in favor of obtaining relatively uniform velocity distribution. By the combination of the calculation of frictional resistances with descriptive geometry, it can predict the trend of velocity distribution among microchannels with the variation of structural parameters without applying complicated theoretical model or numerical simulation. [ABSTRACT FROM AUTHOR]

Abstract: LaMnO3, LaFeO3, LaCoO3 and LaNiO3 perovskite oxides were prepared using combustion method for autothermal reforming of ethanol (ATRE). Fresh, reduced and used catalysts were characterized by XRD, TEM, ethanol-TPD, and H2-TPR. The perovskite-type oxides exhibit moderate activities in the ATRE reaction. Well dispersed Ni particles on lanthanum oxide species were obtained by reducing the LaNiO3 sample. It favors the dehydrogenation, decomposition of ethanol/acetaldehyde, methane reforming and water gas shift reactions, thus leads to good activity and H2 selectivity in ATRE reaction. Typically, 3.2 H2 molecules per ethanol molecule were produced at EtOH:H2O:O2 =1:2:0.98 and GHSV=4×105 h−1. A comparison between LaNiO3 derived and impregnated Ni/La2O3 shows that the LaNiO3 derived sample favored the dispersion of Ni, which increased the activity and the resistance to coke deposition. [Copyright &y& Elsevier]

Abstract: A water-soluble cationic flocculant, a copolymer of acrylamide (AM) and acryloylamino-2-hydroxypropyl trimethyl ammonium chloride (AMHP), was synthesized through dispersion polymerization method in aqueous ammonium sulfate ((NH4)2SO4) solution. The polymerization was initiated by gamma-radiation using poly(2-methylacryloylxyethyl trimethyl ammonium chloride) (PDMC) as the stabilizer. The obtained copolymer was characterized by using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), colloidal titration and optical microscopy. Its flocculation properties were evaluated with 0.25wt% kaolin suspensions using a standard jar test. The zeta potential of supernatant at different flocculant dosage was simultaneously measured. The results demonstrate the superiority of the copolymer over the commercial polyacrylamide as a flocculant. [Copyright &y& Elsevier]

• 10.3% nitrogen-self-doped graphite nanofibers are first prepared by laser writing. • The resulting nanofibrous structure differs from traditional porous structure. • The formation mechanism of vertically-oriented graphite nanofibers is clarified. • The graphite nanofibers exhibit high-temperature stability up to 470 °C in air. • Capacitance of IMSCs is 58 mF/cm2, which is 7 times that of laser-induced graphene. The fabrication of high-content heteroatoms-doped carbon nanomaterials is crucial for energy storage. Conventional external heteroatoms-doping usually needs complex and time-consuming preparation processes. Here, we report the facile and high-efficient fabrication of high-content (10.3%) nitrogen-self-doped graphite in the form of banyan root hairs-like nanofibers by laser direct writing on nitrogen-enriched cyanate ester. The resulting laser-induced graphite nanofibers (LIGNFs) exhibit high-temperature stability up to 470 °C in air, which outperforms the laser-induced graphene (LIG), laser-sculptured carbide and MXenes. The medium power level of laser can produce high quality and uniform distributed nanofibers, while the high power level could generate root nodule-like and even agglomerated nanofibers with more effective conductive network and higher nitrogen content, leading to relatively low quality but lower sheet resistance (21.50 Ω/square). Benefiting from the reverse surface atom-controlled pseudocapacitive effect, the LIGNFs-based on-chip in-plane micro-supercapacitors (LIGNFs-IMSCs) provide a superior areal capacitance of 57.96 mF/cm2, which is about seven times as high as that of LIG-based IMSCs. Additionally, the LIGNFs-IMSCs present excellent cycling stability and nearly 100% coulombic efficiency after 12,000 cycles. The novel LIGNFs with high-efficient preparation process, high-thermal stability and excellent electrochemical performance may have promising applications for energy storage devices in extreme environments. [ABSTRACT FROM AUTHOR]

• Synchronous induction & activation of porous graphene on flexible substrate in air. • The activation mechanism of porous graphene via direct laser writing is demonstrated. • The effects of KOH on morphology, composition and wettability are studied. • Medium concentration of KOH can improve the quality and wettability of graphene. • IMSCs provide 10 times higher energy density than that without activation. Laser-induced graphene (LIG) from polymers has aroused considerable attentions for its low cost and high efficiency fabrication and prospect applications in flexible micro-energy storage devices. However, its electrochemical performance has been constrained by its purity and macropore-dominated structures. Herein, a one-step, facile approach is reported for synchronous induction and activation of 3D porous graphene from KOH-coated polyimide film by direct laser writing in ambient air. To explore the activation mechanism, the effects of two physical forms of KOH (crystal and solution) with various concentrations are investigated. Studies reveal that medium concentrations of KOH are able to improve the quality, heteroatoms (nitrogen and oxygen) doping and wettability of porous graphene in comparison with lower KOH. Additionally, high concentrations of KOH contribute to the formation of carbon atomic defects and mesoporous structures with increased content of nitrogen (4.94%). Benefiting from the improvement of activation, the laser-induced and activated graphene-based in-plane micro-supercapacitors present an areal capacitance of 32.00 mF/cm2 (4.27 μWh/cm2), which is about 10 times higher than that without KOH activation. Good cycling stability, excellent mechanical flexibility, and outstanding modular integration have been accomplished. As such, these high-performance devices hold enormous potentials for flexible and wearable electronics. [ABSTRACT FROM AUTHOR]

• The sandwich-structured cathode is fabricated by a layer-by-layer coating process. • The conductive micro-cracked layer achieves a large surface of current collector. • The interlayer of MWCNT and Li 4 Ti 5 O 12 composite is directly coated on S cathode. • The integrated cathode improves its internal electrical/ionic conductivity. • The unique cathode exhibits an enhanced electrochemical performance. The high-energy and low-cost lithium-sulfur (Li-S) battery is regarded as a new generation energy-storage device. However, the Li-S battery mostly suffers from low electronic conductivity and poor cycle capability. This study reports on a novel sandwich-structured cathode with optimized electrode architecture and interface design of the current collector (named as M-S-LTO) made by a facile layer-by-layer slurry coating process. The new integrated electrode is composed of a micro-cracked current collector (MCC) based on multi-wall carbon nanotubes, a middle layer of sulfur/carbon material and an upper current collector&interlayer (UCC&I) based on multi-wall carbon nanotubes and Li 4 Ti 5 O 12 nanospheres. The M-S-LTO cathode produces a better electrochemical performance because of its improved internal electrical and ionic conductivity, stable structure and mitigation of shuttle effect, in contrast to the sulfur electrode with either an MCC (M-S cathode) or a smooth aluminum foil current collector (S cathode). At a current density of 0.2 C, the Li-S battery with the M-S-LTO cathode delivers a high initial capacity of 1248.6 mAh g−1 and retains a reversible capacity of 960.3 mAh g−1 after 200 cycles. Even at 1 C, its capacity can reach 773.4 mAh g−1 after 200 cycles. The battery with the M-S-LTO cathode shows a higher cycle performance than most of other reported cells based on the interlayer design with a comparable sulfur loading. With the enhanced electrochemical performance, the new cathode offers a promising avenue to fabricate high-performance Li-S batteries. [ABSTRACT FROM AUTHOR]