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Porcine contagious pleuropneumonia, caused by Actinobacillus pleuropneumoniae, has resulted in significant economic losses to the swine industry. Although antibiotics are commonly employed to control this disease, their widespread use or misuse can lead to the development of antibiotic resistance in A. pleuropneumoniae. Consequently, it is crucial to conduct antimicrobial susceptibility testing on clinical isolates. In our study, we identified one strain of A. pleuropneumoniae with resistance to florfenicol and extracted a 5919 bp plasmid named pAPPJY, which confers florfenicol resistance. Sequence analysis revealed that the plasmid contains four open reading frames, namely rep, antioxin vbha family protein, floR, and a partial copy of lysr. Although a few variations in gene position were observed, the plasmid sequence exhibits a high degree of similarity to other florfenicol-resistant plasmids found in Glaesserella parasuis and A. pleuropneumoniae. Therefore, it is possible that the pAPPJY plasmid functions as a shuttle, facilitating the spread of florfenicol resistance between G. parasuis and A. pleuropneumoniae. In addition, partial recombination may occur during bacterial propagation. In conclusion, this study highlights the horizontal transmission of antibiotic resistance among different bacterial species through plasmids, underscoring the need for increased attention to antibiotic usage. [ABSTRACT FROM AUTHOR]

The role of the mid‐latitude seaway between the proto‐Paratethys and the North Sea on the early Paleogene ocean circulation is examined with a state‐of‐art earth system model. The early Eocene simulations here demonstrate that the open mid‐latitude seaway captures most relatively fresh surface water from the Arctic and Greenland‐Norwegian Sea and prohibits them from leaking into the Labrador Sea, thus benefiting the Atlantic meridional overturning circulation (AMOC). However, the closure of the seaway triggers the AMOC reduction as more relatively fresh surface water enters the Labrador Sea, and the AMOC finally shuts down. Together with geological reconstructions, our results also provide insights into understanding the evolution of the Atlantic‐Arctic oceanic gateways during the Paleogene. Plain Language Summary: Recent geological evidence demonstrated that a mid‐latitude seaway connected the proto‐Paratethys sea and the North Sea during the early Eocene. Then, this connection was closed since the late Eocene‐early Oligocene. Here, using climate modeling, we investigated the effects of this mid‐latitude seaway evolution, particularly in modulating the Atlantic meridional overturning circulation (AMOC). Our simulations show that the open seaway prohibits the relatively fresh Arctic surface water from leaking into the Labrador Sea and thus favors the formation of AMOC. On the contrary, the closed seaway allows more relatively fresh Arctic surface water to influence the Labrador Sea, thus triggering the AMOC reduction. Our study pinpoints a controlling role of the mid‐latitude seaway in modulating global ocean circulation during the early Paleogene. Key Points: The evolution of the mid‐latitude seaway in the early Paleogene influences ocean circulationThe opening of the seaway favors the Atlantic meridional overturning circulation (AMOC), while its closing leads to AMOC shutdown [ABSTRACT FROM AUTHOR]

It is quite a challenge to obtain the temperature and species concentration fields of muzzle flash at high noise level. In this numerical study, radiation intensity of muzzle flash received by the high-speed Complementary Metal-Oxide-Semiconductor (CMOS) camera was simulated based on the line-of-sight method in the direct radiative transfer problem. The inverse radiative transfer problem of reconstructing distributions of temperature and soot volume fraction from the knowledge of flame radiation intensity was transformed into a minimization optimization problem and a meta-heuristic algorithm was used to solve the problem. The effects of the number of detection lines, optical thickness and measurement errors on the reconstruction results were discussed in details. A method to estimate the noise level of radiation intensity was developed, experimental results showed that the signal-to-noise ratio (SNR) of radiation intensity can be successfully inferred when the SNR is greater than 20 dB. Subsequently, prior knowledge of the noise level was introduced in the regularization to achieve a meaningful approximation of the exact value. The reconstruction of the soot volume fraction filed with SNR greater than 40 dB is considered successful with the inclusion of an appropriate regularization term in the objective function, and the reconstruction of the temperature field is feasible even with SNR as low as 15 dB. The high tolerance to the noise level of the radiation intensity gives the reconstruction algorithm the potential to be used in practical experiments of muzzle flash. [ABSTRACT FROM AUTHOR]

Shell and tube horizontal thermosyphon reboilers (STHTs) find wide applications in the process industry particularly due to their inherent advantages in handling large duties, high viscosity fluids and low fouled susceptibility. However, current design commercial packages suffer from obvious limitations including extensive user manipulations, trial-and-error necessity, increased human factor influence. To overcome these limitations, we develop in this work a rigorous MINLP model for STHT sizing, by achieving automated selection of detailed exchanger geometries with optimal overall heat transfer coefficient. The corrected minimum cross-flow area in shell-side is incorporated to accommodate full cross-flow patterns in tube bundle, thus handling popular service of X shell without baffle construction. A dependable convective boiling heat transfer model is proposed to obtain the shell-side heat transfer coefficient, validated with Aspen EDR. The critical variable, heat flux, which affects nucleate boiling heat transfer performance, is optimized through a simultaneous equation-solving process using a global solver, reducing excessive unit overdesign. Pressure balance between STHT and distillation column is fully considered by a proposed optimization model incorporating pressure drop and pipe sizing. By employing global optimization techniques and automating the design process, this innovative approach minimizes manual adjustments and provides more accurate and cost-effective designs. • A novel mathematical model is proposed for the design of shell and tube horizontal thermosyphon reboiler. • The formulation for two-phase shell-side boiling heat transfer is presented in detail. • Reboiler geometries associated with heat transfer performance are optimized through a global optimization strategy. • Systemic pressure balance is carried out to maintain stability in horizontal thermosyphon reboiler operation. [ABSTRACT FROM AUTHOR]

Manganese oxides/graphene is an electrode material currently under consideration for use in high-performance supercapacitors (SCs). The conventional, widely used wet chemical methods for preparing MnO2/graphene are tedious and consume large quantities of strong reduction/oxidation reagents. The resulting powder composites require adhesives to form a suitable electrode. In the present study, we report on a method for synthesizing MnO2/graphene composite electrodes using a second laser irradiation employing a laser of the polyether ether ketone. This simple and environmentally friendly method allows the patterning of electrodes together with the synthesis of the active materials. The MnO2/laser-induced graphene (LIG) electrode exhibited a high capacitance of 48.9 mF cm−2, which is about 2.4 times greater than a pure LIG electrode. Assembled all solid micro-supercapacitors (MSCs) containing the novel LIG electrodes delivered both high energy density (3.1 μWh cm−2) and power density (2.5 mW cm−2). These MSCs exhibited a capacitance retention of 94.3% over 3000 cycles, at a current density of 0.5 mA cm−2. The electrochemical performance was almost unaltered by bending the MSC to 150°. This method of synthesizing high-performance flexible electrodes is important for future development of wearable electronics. [ABSTRACT FROM AUTHOR]

In this work, Schottky barrier-free 2D reconfigurable FETs are constructed via imbedding contact gate in normal device geometry. Though applying different contact gate voltages, the FETs can be flexibly defined and switched between p -type mode and n -type mode with high mobility and ultra-small SS values. High gain low power consumption complementary inverters are further demonstrated. The newly emerged two-dimensional (2D) semiconducting materials, owning to the atomic thick nature and excellent optical and electrical properties, are considered as potential candidates to solve the bottlenecks of traditional semiconductors. However, the realization of high performance 2D semiconductor-based field-effect transistors (FETs) has been a longstanding challenge in 2D electronics, which is mainly ascribing to the presence of significant Schottky barrier (SB) at metal-semiconductor interfaces. Here, an additional contact gate is induced in 2D ambipolar FET to realize near ideal reconfigurable FET (RFET) devices without restrictions of SB. Benefitting from the consistently high doping of contact region, the effective SB height can be maintained at ultra-small value during all operation conditions, resulting in the near ideal subthreshold swing (SS) values (132 mV/decade for MoTe 2 RFET and 67 mV/decade for WSe 2 RFET) and the relatively high mobility (28.6 cm2/(V s) for MoTe 2 RFET and 89.8 cm2/(V s) for WSe 2 RFET). Moreover, the flexible control on the doping polarity of contact region enables the remodeling and switching of the achieved unipolar FETs between p -type mode and n -type mode. Based on such reconfigurable behaviors, high gain complementary MoTe 2 inverters are further realized. The findings in this work push forward the development of high-performance 2D semiconductor integrated devices and circuits. [ABSTRACT FROM AUTHOR]

Presented herein is a study on the ignition reaction kinetics and mechanism of B4C/KNO3 and B4C/KClO4 pyrotechnic smoke compositions using the non-isothermal thermogravimetry and differential scanning calorimetry techniques. The pyrotechnics in oxygen balance of − 10%, − 20% and − 30% were prepared for the experiments. The results of measurements showed that the pyrotechnics in oxygen balance of − 20% had the highest enthalpy. The activation energy (Ea) of ignition reactions was calculated by using Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunose (KAS) methods. The Ea values of B4C/KNO3 and B4C/KClO4 were 139.5 and 214.6 kJ mol−1 calculated by OFW method, and 129.3 and 210.7 kJ mol−1 by KAS method. The differential and integral reaction mechanism functions of B4C/KNO3 and B4C/KClO4 were determined, respectively, by z(α) master plots method, f1(α) = 2(1 − α)[− ln(1 − α)]1/2, g1(α) = [− ln(1 − α)]1/2, and f2(α) = 3(1 − α)[− ln(1 − α)]2/3, g2(α) = [− ln(1 − α)]1/3. The pre-exponential factors, lnA = 11.6 and 22.3 min−1, were obtained by the intercept of KAS method for ignition reaction of B4C/KNO3 and B4C/KClO4 pyrotechnics. Based on the results, the burning rates, thermal sensitivities and application methods of B4C/KNO3 and B4C/KClO4 were predicted. [ABSTRACT FROM AUTHOR]

In this work, we develop a new strategy to get p-n junctions along 2D conduction channel, where photogating layer is used to replace the common used local gates, and light is employed as the input instead of the gate voltage that is applied on the device to define the p-n junctions. Such light-triggered p-n junctions, with simple device configuration and low energy consumption, will provide a new concept for novel optoelectronic devices and expand their range of applications in modern opto-electrical interconnection circuits. The realization of light-triggered devices where light is used as external stimulus to control the device performances is a long-standing goal in modern opto-electrical interconnection circuits. In this work, it reveals that light illumination can induce the formation of p-n junctions along two-dimensional conduction channels. The results indicate that the dominant charge carrier type and density in black phosphorus (BP) conduction channel can be effectively modulated by the underlying cadmium sulfide (CdS) photo-gate layer under light illumination. This enables flexible switching of the working state between BP resistor and BP p-n diode in the designed semi-photo-gate transistor (SPGT) devices when switching the light on and off (ultra-low threshold light power). Simultaneously, the achieved BP p-n junctions also exhibit ultra-high photoresponsivity and evident photovoltaic properties. That is to say, light can be employed as external stimulus to define the BP p-n junctions, and in turn the p-n junctions will further convert the light into electrical power, showing all-in-one opto-electrical interconnection properties. Moreover, the SPGT device architecture is also applicable for construction of other ambipolar semiconductor-based (WSe 2 - and MoTe 2 -based) p-n diodes. Such universal all-in-one light-triggered lateral homogeneous p-n junctions with ultra-low energy consumption should open a new pathway toward novel optoelectronic devices and deliver various new applications. [ABSTRACT FROM AUTHOR]

The splicing of organelle-encoded mRNA in plants requires proteins encoded in the nucleus. The mechanism of splicing and the factors involved are not well understood. Pentatricopeptide repeat (PPR) proteins are known to participate in such RNA–protein interactions. Maize defective kernel 41 (dek41) is a seedling-lethal mutant that causes developmental defects. In this study, the Dek41 gene was cloned by Mutator tag isolation and allelic confirmation, and was found to encode a P-type PPR protein that targets mitochondria. Analysis of the mitochondrial RNA transcript profile revealed that dek41 mutations cause reduced splicing efficiency of mitochondrial nad4 intron 3. Immature dek41 kernels exhibited severe reductions in complex I assembly and NADH dehydrogenase activity. Up-regulated expression of alternative oxidase genes and deformed inner cristae of mitochondria in dek41 , as revealed by TEM, indicated that proper splicing of nad4 is essential for correct mitochondrial functioning and morphology. Consistent with this finding, differentially expressed genes in the dek41 endosperm included those related to mitochondrial function and activity. Our results indicate that DEK41 is a PPR protein that affects cis -splicing of mitochondrial nad4 intron 3 and is required for correct mitochondrial functioning and maize kernel development. [ABSTRACT FROM AUTHOR]

The evolution of Cenozoic climate patterns in Asia has been linked to uplift of the Tibetan Plateau (TP), retreat of the Paratethys Sea, and global cooling. However, less attention has been placed on the latitudinal change of the TP. Here we report new climate modeling to explore how modern climate changes as a function of topographic growth and spatial migration of the TP. Our results show that the northward displacement of the uplifted proto‐TP within the subtropics can significantly affect the wind and precipitation pattern over East‐Central Asia. By compiling proxy‐based climatic records, paleolatitudinal and paleoelevational evolution models of the proto‐TP, and in comparison with previous modeling under a global paleogeography, we suggest that the northward migration of the proto‐TP in the Paleogene could have intensified the aridity in Central Asia, but its influence on East Asian precipitation and monsoonal circulation could be dependent on the paleogeography and other boundary conditions. Plain Language Summary: The evolution of the Asian monsoons and aridification of Asia's interior are thought to be driven by Tibetan‐Himalayan uplift. Recent geological observations suggest that the uplifted proto‐Tibetan Plateau (proto‐TP) migrated northward in the subtropics since the early Eocene and reached its present position by the latest Oligocene. We therefore simulated the effects of this process on East‐Central Asian climate. Our climate modeling shows the northward migration of the high proto‐TP from 21–29°N to 29–37°N can significantly change the present‐day wind and precipitation patterns over East‐Central Asia. Especially, Central Asia become drier because of the displacement of the anomalous dry belt caused by large‐scale atmospheric subsidence. We further suggest that forcing by the paleolatitudinal migration of the high proto‐TP within the subtropics from the Eocene to the earliest Miocene could have drove the Central Asian paleoclimate to dryer conditions, but migration might not be the sole parameter that governed the East Asian monsoon during the Paleogene. Key Points: The high proto‐Tibetan Plateau migrating northward can notably influence the modern East‐Central Asian climate systemCentral Asian aridification increased with the northward migration of the proto‐Tibetan Plateau in the PaleogeneThe impact of Paleogene proto‐Tibetan Plateau migration on East Asian climate could be dependent on boundary conditions [ABSTRACT FROM AUTHOR]

DSC experiments were conducted on the 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-tetracyclo-[5.5.0.05,9.03,11]-dodecane (also known as HNIW or CL-20) and CL-20 containing 10 wt.% microsized aluminum (Al) powders. The kinetic parameters of CL-20 and CL-20/Al were obtained by ASTM685 and Friedman methods, respectively, indicating that Al powder decreases the activation energy of CL-20 slightly and has a catalytic effect on the thermal decomposition of CL-20. By the method of nonlinear multivariate regression, kinetic models of CL-20 and CL-20/Al were derived as fα=1−αn1+kcat⋅α, where the lgkcat of CL-20 and CL-20/Al is 1.97 and 2.12, respectively, showing that the autocatalytic ability of CL-20 had been increased by adding Al powder. From the SEM images of CL-20/Al and the XRD pattern of the decomposition residues of CL-20/Al, it can be inferred that partial combustion of Al particles happened in the microscale view and led to the release of heat. [ABSTRACT FROM AUTHOR]

Graphene-based micro-supercapacitors exhibit excellent electrochemical performance that can easily meet the energy storage requirements of micro-electronic products. However, the complex preparation and transfer process steps of traditional preparation methods limit their wide application. Direct laser writing can deposit graphene laser-induced graphene (LIG) onto a specific substrate-patterned electrodes. This approach offers great advantages in the preparation of miniature and complex-patterned electrodes, but currently there is a limited choice of precursor materials. In this reported study, biocompatible polyether ether ketone (PEEK) was irradiated using a high repetition rate picosecond laser to produce graphene. Various photothermal and photochemical reactions were involved in the one-step conversion of PEEK into a film comprised of a several layers (3-4) of graphene. The electrochemical testing of a three-electrode system containing this novel graphene showed that LIG had a specific capacitance of 20.4 mF cm−2 at a scan speed of 10 mV s−1, and the capacitance was reversibly maintained with 89.37% retention of the initial capacitance after 5000 cycles. The novel LIG with higher specific capacitance and cycle stability has great potential for use in energy storage micro-devices. [ABSTRACT FROM AUTHOR]

The overexpression of algal glutamine synthetase (GS) gene DvGS2 in Arabidopsis thaliana resulted in higher plant biomass and better growth phenotype. The purpose of this study was to understand the biological mechanism for the improvement of growth phenotype of DvGS2-transgenic Arabidopsis. A series of molecular and biochemical investigation related to nitrogen and carbon metabolism in DvGS2-transgenic line was, respectively, conducted. Analysis of nitrogen use efficiency (NUE)-related gene expression and enzymatic activity revealed that the transcriptional level and enzymatic activity of genes encoding glutamate synthase, glutamate dehydrogenase and alanine aminotransferase were significantly up-regulated especially under low nitrate condition. The DvGS2-transgenic line showed higher total nitrogen content and lower carbon: nitrogen ratio than the wild type. Significant reduced concentration of leaf free ammonium, higher concentrations of total amino acids, individual amino acid (glutamine, methionine, alanine, asparagine) together with increased concentrations of glucose, fructose and starch, confirmed the higher efficiency of nitrogen and carbon assimilation. These improved metabolisms of nitrogen and carbon conferred the DvGS2-transgenic Arabidopsis more biomass, better growth phenotype and higher NUE compared with the wild type plant. [ABSTRACT FROM AUTHOR]

Abstract: The salt-tolerant green alga Dunaliella has remarkable capability to survive in some extreme environments such as nitrogen starvation, which makes Dunaliella be a proper model for mining novel genes on nitrogen uptake or assimilation. In this study, a glutamine synthetase (GS) gene DvGS2 with amino acid identity of 72% to other homologous GS proteins, was isolated and characterized from Dunaliella viridis. Phylogenetic comparison with other GSs revealed that DvGS2 occupied an independent phylogenetic position. Expressional analysis in D. viridis cells under nitrogen starvation confirmed that DvGS2 increased its mRNA level in 12h. Subcellular localization study and functional analysis in a GS-deficient Escherichia coli mutant proved that DvGS2 was a chloroplastic and functional GS enzyme. In order to investigate the potential application of DvGS2 in higher plants, the transgenic studies of DvGS2 in Arabidopsis thaliana were carried out. Results showed that the transgenic lines expressed the DvGS2 gene and demonstrated obviously enhanced root length (29%), fresh weight (40%–48% at two concentrations of nitrate supplies), stem length (21%), leaf size (39%) and silique number (44%) in contrast with the wild-type Arabidopsis. Furthermore, the transgenic lines had higher total nitrogen content (35%–43%), total GS activity (39%–45%) and soluble protein concentration (23%–24%) than the wild type. These results indicated that the overexpression of DvGS2 in A. thaliana resulted in higher biomass and the improvement of the host's nitrogen use efficiency. [Copyright &y& Elsevier]

[Display omitted] • 1. A novel general method for metal oxide nanoparticles (MONPs) modified laser-induced graphene (LIG) electrode. • 2. MONPs (M = Ti, Ni, Sn) with a diameter of 5–10 nm were synthesized by laser ablation in liquid. • 3. The preparation process of MONPs modified LIG electrodes are simple, low-cost and green. • 4. SnO 2 /LIG micro-supercapacitors display high area-specific capacitance (18.58 mF cm−2 at 10 mV s−1) and mechanical stability. Metal oxide nanoparticles (MONPs)-graphene composites are highly valued candidate electrode materials for electrochemical supercapacitor (SC). Here, we described the development of a versatile approach for fabricating SC electrodes by impregnating MONPs (M = Ti, Ni, Sn) synthesized by laser ablation in liquid on laser-induced graphene (LIG). A typical SnO 2 /LIG micro-supercapacitor (MSC) delivers an area-specific capacitance of 18.58 mF cm−2 at a scan rate of 10 mV s−1, which is 5.2 times greater than the unmodified LIG. Moreover, the MSC exhibits long-life cycling stability (retaining 82.15% of specific capacitance after 5000 cycles) and good mechanical flexibility (specific capacitance is reduced by 5% at bending angle of 150°). MONPs and LIG are prepared using the same laser processing system, and no chemical ligands or reducing agents used in the synthesis process, which is cost-effective and green. This simple and straightforward method provide a highly operable solution for the large-scale preparation of MSC. [ABSTRACT FROM AUTHOR]

To investigate the blast resistance of point-supported glass curtain wall, a series of site blast tests were conducted, considering two types of glass thicknesses and different TNT charges from 0. 4 kg to 30 kg. The overpressure and displacement were measured and the failure mode was observed. The tests show the following results. The overpressure suddenly increases and quickly decays within a few milliseconds. The displacement response of the glass curtain wall increases with the increase of TNT charge. The increase of the glass thickness reduces the displacement response of the point-supported glass curtain wall. The failure mode is the tearing off of PVB at the support of the laminated glass panel while the glass shards still adhere to the PVB. Nonlinear dynamic finite element simulation of the blast tests show that, the difference of displacement response obtained by finite element analysis and blast test is less than 35%, severe stress concentration exists at the rim of support hole and finally causes the failure at the support hole, which agrees with the failure mode observed from the blast test. [ABSTRACT FROM AUTHOR]

A Bacillus subtilis strain BEC-1 demonstrating high carboxymethylcellulose-degrading activity was isolated from the forest soil sample. In order to characterize the biochemical specialty of its cellulase, the endoglucanase gene egl173 was cloned from this strain and was expressed in Escherichia coli. The gene encoded a protein of 499 amino acids with a molecular weight of 64 kDa. The purified Egl173 could hydrolyze both soluble and insoluble celluloses with distinct activities. This enzyme showed the highest enzyme activity at pH 4, maintained at least 85% activity in the pH range of 3-7, displayed maximum activity at 60°C and was highly stable between 30 and 60°C. It was found that this endoglucanase was increasedly active and retained its high stability after incubation with 5 M NaCl or 3 M KCl for 24 h. Furthermore, after incubation with 10 mM of dithiothreitol, the enzyme activity was significantly enhanced (125% of the control level). In the presence of diverse metal ions (except mercury and manganese cations), organic solvents, surfactants (except SDS) and chelating agent, this enzyme kept more than 85% active. This halo-tolerant, acidophilic and highly stable endoglucanase is prospectively to be exploited as the advanced enzymatic product for diverse industrial applications. [ABSTRACT FROM AUTHOR]

Summary: Methanogenesis from the biomass in the anoxic biogas reactors is catalyzed by syntrophic cooperation between anaerobic bacteria, syntrophic acetogenic bacteria and methanogenic archaea. Understanding of microbial community composition within the biogas reactors may improve the methane production from biomass fermentation. In this study, methanogenic archaea diverity of a biogas reactor supplied with swine feces as mono-substrate under mesophilic conditions was investigated. Community composition was determined by analysis of methyl coenzyme reductase subunit A gene (mcrA) clone library consisting of 123 clones. Statistical analysis of mcrA library indicated that all major groups of methanogens from our biogas reactor were detected. In the library, 57.7% clones were affiliated to Methanobacteriales, 34.2% to Methanomicrobiales, 2.4% to Methanosarcinales and about 5.7% clones belonged to unclassified euryarchaeota. Over 90% of the methanogenic archaea from our biogas reactor were postulated to be hydrogenotrophic methanogens. Comparing with other previous studies reporting that hydrogenotrophic methanogens are dominant species in the biogas plants, this study firstly reported that Methanobacteriales instead of Methanomicrobiales are the most predominant methanogenic archaea in the biogas reactor fed with swine feces as sole substrate. [ABSTRACT FROM AUTHOR]

The key to deep learning vulnerability detection framework is pre-processing source code and learning vulnerability features. Traditional source code representation techniques take a complete normalization to user-defined symbols but ignore the semantic information associated with vulnerabilities. The current mainstream vulnerability feature learning model is Recurrent Neural Network (RNN), whose time-series structure determines its insufficient remote information acquisition capability. This paper proposes a new vulnerability detection framework to solve the above problems. We propose a new data normalization method in the source code pre-processing phase. The user-defined symbols are clustered using the unsupervised clustering algorithm K-means. The normalized classification is performed according to the clustering results, which preserves the primary semantic information in the source code and ensures the smoothness of the sample data. In the feature extraction stage, we input the source code after performing text representation into Bidirectional Encoder Representations for Transformers (BERT) for feature automation learning, which enhances semantic information extraction and remote information acquisition. Experimental results show that the vulnerability detection precision of this method is 18.3% higher than that of the current mainstream vulnerability detection framework in the real-world data collected by ourselves. Further, our method improves the precision of the state-of-the-art method by 4.2%. [ABSTRACT FROM AUTHOR]

Optoelectronic integrated circuits, with a broad photonic transportation bandwidth, have emerged as a promising solution to fulfill the escalating demands for high-volume information transportation and processing. However, challenges persist in developing optoelectronic integrated circuits based on low-dimensional nanostructures, including limited integration density and high energy consumption. Here, we demonstrate a bidirectional optoelectronic device by integrating a light-emitting/harvesting CsPbBr3 nanoplate with a waveguiding/modulating/detecting CdS nanobelt. By configuring the CsPbBr3 nanoplate in a Schottky-type device structure with a metal electrode, bright electroluminescence was attained at a bias voltage of 18 V. Thanks to the electric field-tuned phonon-coupling effect, the waveguided light in the CdS nanobelt exhibited a high modulation depth of up to 94%, rendering it an excellent building block as optical modulators and optical switches. Moreover, the integrated nanostructure device showcased functionality in the photodetection mode. The proposed device architecture holds promise for broader applications, potentially extending to other perovskite-coupled II–VI semiconductor optoelectronic integrated circuits for expanding integration capacity and enhancing optoelectronic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] The growth of data and Internet of Things challenges traditional hardware, which encounters efficiency and power issues owing to separate functional units for sensors, memory, and computation. In this study, we designed an α-phase indium selenide (α-In 2 Se 3) transistor, which is a two-dimensional ferroelectric semiconductor as the channel material, to create artificial optic-neural and electro-neural synapses, enabling cutting-edge processing-in-sensor (PIS) and computing-in-memory (CIM) functionalities. As an optic-neural synapse for low-level sensory processing, the α-In 2 Se 3 transistor exhibits a high photoresponsivity (2855 A/W) and detectivity (2.91 × 1014 Jones), facilitating efficient feature extraction. For high-level processing tasks as an electro-neural synapse, it offers a fast program/erase speed of 40 ns/50 µs and ultralow energy consumption of 0.37 aJ/spike. An AI vision system using α-In 2 Se 3 transistors has been demonstrated. It achieved an impressive recognition accuracy of 92.63% within 12 epochs owing to the synergistic combination of the PIS and CIM functionalities. This study demonstrates the potential of the α-In 2 Se 3 transistor in future vision hardware, enhancing processing, power efficiency, and AI applications. [ABSTRACT FROM AUTHOR]

During the Cretaceous, there were two factors that had important influences on the East Asian climate, the East Asian coastal mountains and Earth's orbital cycling. An important question is how the coastal mountains modulated the variability of East Asian climate over orbital timescales. Here, we perform simulations with the coastal mountains of 0, 2, and 4 km high and three orbital configurations to answer the question. Our results show that a mountain range at the East Asian coast can amplify the impacts of orbital forcing on East Asian climate. Specifically, precipitation over the Songliao Basin in Northeastern China has significant changes as the coastal mountain range is about 4 km high. Combining our simulation results with orbitally‐controlled sedimentary deposits from the Songliao Basin, we conclude that the altitude of the coastal mountain range was very likely higher than 2 km in the Late Cretaceous. Plain Language Summary: Tectonic events and solar insolation are the two important factors impacting variations of the climate system in the geological past. Regional climate responses to variations in the radiation from the sun over 104–105 years were often magnified or dampened by tectonic events. Cretaceous sedimentary records in East Asia suggest that East Asian climate was influenced by the solar insolation. Geological evidence showed that a mountain range existed along the East Asian coast then. Would this mountain range modulate impacts of solar insolation on East Asian climate? Our modeling results show that the influence of solar insolation on East Asian climate can be amplified by the coastal mountain range, depending on the mountain elevation. When the coastal mountain range is ∼2 km high, the amplification effects become significant. When its altitude reaches ∼4 km, the response of East Asian climate to solar insolation is considerably strengthened, and such a condition is supported by the rhythm induced by the climate variation due to solar insolation archived in the Cretaceous strata in the Songliao Basin. Thus, we speculate that the East Asian coastal mountains might have reached an altitude more than 2 km in the Late Cretaceous. Key Points: East Asian climate was sensitive to orbital forcing in the Late CretaceousEast Asian coastal mountains amplified orbital forcing on East Asian climate variabilityEast Asian coastal mountains were likely higher than 2 km in the Late Cretaceous [ABSTRACT FROM AUTHOR]

The Middle Miocene was a period of prominent climatic change, marked by the Mid-Miocene Climatic Optimum (MMCO) and the subsequent global cooling due to a decline of the atmospheric CO 2 concentrations (p CO 2). In addition to this, the closure of the Tethyan Seaway driven by the Arab-Eurasia collision also had an important effect on the paleoclimatic changes during this period. In this study, we use the Community Earth System Model 1.2.2 (CESM 1.2.2) to simulate the effects of global cooling (i.e. p CO 2 decline) and the closure of the Tethyan Seaway on the North African and South Asian climates. Our results show that the global cooling led to a precipitation decrease over both North Africa and South Asia, whereas the closure of the Tethyan Seaway resulted in a precipitation decrease over North Africa but an increase over South Asia. The opposite effects over North Africa and South Asia are due to an increased moisture transport from North Africa to South Asia induced by stronger summer atmospheric circulation when the Tethyan Seaway is closed. We further show that the reconstructed records of drying conditions over North Africa during the warming period from the late Early Miocene to the early Middle Miocene from previous studies can be partly explained by the narrowing of the Tethyan Seaway and its climatic continuing deterioration due to the subsequent final closure and global cooling. Both are precursory conditions for the formation of the Sahara desert. The stronger South Asian monsoon during the Middle Miocene transient cooling period found in previous studies can be partially attributed to the final closure of the Tethyan Seaway. • Closure of the Tethyan Seaway led to precipitation increase in South Asia but decrease in North Africa. • Closure of the Tethyan Seaway led to enhanced moisture transport from North Africa to South Asia. • Global cooling led to precipitation decrease in North Africa and South Asia during the MMCT. [ABSTRACT FROM AUTHOR]

Optoelectronic synaptic devices integrating light‐perception and signal‐storage functions hold great potential in neuromorphic computing for visual information processing, as well as complex brain‐like learning, memorizing, and reasoning. Herein, the successful growth of MoS2 monolayer arrays assisted by gold nanorods guided precursor nucleation is demonstrated. Optical, spectral, and morphology characterizations of MoS2 prove that arrayed flakes are homogeneous monolayers, and they are further fabricated as optoelectronic devices showing featured photocurrent loops and stable optical responses. Typical synaptic behaviors of photo‐induced short‐term potentiation, long‐term potentiation, and paired pulse facilitation are recorded under different light stimulations of 450, 532, and 633 nm lasers at various excitation powers. A visual sensing system consisting of 5 × 6 pixels is constructed to simulate the light‐sensing image mapped by forgetting curves in real time. Moreover, the system presents the ability of utilizing associated images to restore vague and incomplete memories, which successfully mimics human intelligent behaviors of association memory and logical reasoning. The work emulates the brain‐like artificial intelligence using arrayed 2D semiconductors, which paves an avenue to achieve smart retina and complex brain‐like system. [ABSTRACT FROM AUTHOR]

As a kind of high explosives, aluminized explosive cannot release the energy maximumly, which is a key problem. Using DTA-TG equipment, the ignition performance of three kinds of aluminized explosives (RDX, HMX, and CL-20) with different mass percentages of aluminum powder (0%, 10 wt.%, 20 wt.%, and 30 wt.%) was investigated. The results showed that the energy release of the HMX/Al composite explosive with 10 wt.%, 20 wt.%, and 30 wt.% aluminum powder was only equivalent to 80%, 65%, and 36% of pure HMX, respectively. It was similar to RDX/Al and CL-20/Al composite explosives, except the CL-20/Al mixture with 10% aluminum powder. Rather than participating in the ignition and combustion, the aluminum powder does effect the complete reaction of RDX, HMX, and CL-20 in the initial stage of ignition or in the lower temperature area of the boundary. [ABSTRACT FROM AUTHOR]

Heinrich Stadial 1 (HS1) was the major climate event at the onset of the last deglaciation associated with rapid cooling in Greenland and lagged, slow warming in Antarctica. Although it is widely believed that temperature signals were triggered in the Northern Hemisphere and propagated southward associated with the Atlantic meridional overturning circulation (AMOC), understanding how these signals were able to cross the Antarctic Circumpolar Current (ACC) barrier and further warm up Antarctica has proven particularly challenging. In this study, we explore the physical processes that lead to the Antarctic warming during HS1 in a transient isotope-enabled deglacial simulation iTRACE, in which the interpolar phasing has been faithfully reproduced. We show that the increased meridional heat transport alone, first through the ocean and then through the atmosphere, can explain the Antarctic warming during the early stage of HS1 without notable changes in the strength and position of the Southern Hemisphere midlatitude westerlies. In particular, when a reduction of the AMOC causes ocean warming to the north of the ACC, increased southward ocean heat transport by mesoscale eddies is triggered by steeper isopycnals to warm up the ocean beyond the ACC, which further decreases the sea ice concentration and leads to more absorption of insolation. The increased atmospheric heat then releases to the Antarctic primarily by a strengthening zonal wavenumber-3 (ZW3) pattern. Sensitivity experiments further suggest that a ∼4°C warming caused by this mechanism superimposed on a comparable warming driven by the background atmospheric CO2 rise is able to explain the total simulated ∼8°C warming in the West Antarctica during HS1. [ABSTRACT FROM AUTHOR]

• BiVO 4 was used for the first time in the field of thermites. • Al/BiVO 4 exhibits a unique reaction mechanism. • Al/BiVO 4 exhibits superior pressure performance and ignition characteristics. • The superior reactivity is attributed to the gaseous and condensed phase products. Thermites has garnered significant attention due to its high energy density and elevated reaction temperature. However, in most cases, thermites reactions predominantly generate heat and high temperatures while yielding less gas production. Although Al/Bi 2 O 3 exhibits abundant gas generation, it demonstrates lower heat release and is too sensitive. In this study, bismuth vanadate (BiVO 4) is introduced as the oxidizer in thermites for the first time. Al/BiVO 4 exceeds both Al/ Bi 2 O 3 and Al/V 2 O 5 in terms of jetting distance, and the maximum pressure attained by Al/BiVO 4 is nearly double that of Al/ Bi 2 O 3. Additionally, we investigate the reaction mechanism of the Al/BiVO 4 system by means of thermal reaction pathway analysis and characterization of combustion and thermal analysis products. This study unveils a distinctive reaction mechanism during the combustion of Al/BiVO 4 , with bismuth undergoing reduction prior to vanadium. Throughout the entire reaction process, gaseous substances are forcefully released, and the high-temperature solids enhance the generation of gaseous products, resulting in the formation of a flame characterized by a high-temperature particle swarm. The impressive high temperature particle swarm flame and significant pressure output performance and flame jetting distance of the Al/BiVO 4 system confer advantages to its ignition capability. We posit that Al/BiVO 4 holds great potential for various applications in propellants, explosives, and pyrotechnic products. [ABSTRACT FROM AUTHOR]

Self‐powered ultrafast 2D photodetectors have demonstrated great potential in imaging, sensing, and communication. Understanding the intrinsic ultrafast charge carrier generation and separation processes is essential for achieving high‐performance devices. However, probing and manipulating the ultrafast photoresponse is limited either by the temporal resolution of the conventional methods or the required sophisticated device configurations. Here, van der Waals heterostructure photodetectors are constructed based on MoS2/WSe2 p–n and n–n junctions and manipulate the picosecond photoresponse by combining photovoltaic (PV) and photothermoelectric (PTE) effects. Taking time‐resolved photocurrent (TRPC) measurements, a TRPC peak at zero time delay is observed with decay time down to 4 ps in the n–n junction device, in contrast to the TRPC dip in the p–n junction and pure WSe2 devices, indicating an opposite current polarity between PV and PTE. More importantly, with an ultrafast photocurrent modulation, a transition from a TRPC peak to a TRPC dip is realized, and detailed carrier transport dynamics are analyzed. This study provides a deeper understanding of the ultrafast photocurrent generation mechanism in van der Waals heterostructures and offers a new perspective in instruction for designing more efficient self‐powered photodetectors. [ABSTRACT FROM AUTHOR]

The generation, manipulation, and detection of polarized light are the foundations of spin optoelectronics. Polarized light has a wide range of applications in new‐generation information transmission, storage, and quantum communications. Hybrid organic–inorganic halide perovskites have attracted extensive attention recently because of their strong spin–orbit coupling, Rashba splitting, spin‐dependent optical selection, and have been regarded as promising candidates for application in spin optoelectronic devices. Herein, the authors report the successful synthesis of 2D layered lead halide perovskites (PEA)2PbI4 (PEI) doped with magnetic metal Co2+ and the observation of strong circularly polarized photoluminescence and photoresponse. The introduction of magnetic metals in perovskites can induce an analogous Zeeman effect in the system, which can increase its energy degeneracy, giving rise to an imbalanced population of electronic spin states, thereby enhancing the spin polarization in doped samples. Thus, a maximum circularly polarized PL of 35% is observed at room temperature. Moreover, the achieved Co2+‐doped (PEA)2PbI4 also exhibits a selective photoresponse with circularly polarized light (CPL) emission, and an outstanding anisotropy factor of 0.41 for photocurrent is achieved. The experimental results lay the foundation for the controlled synthesis of magnetically doped perovskites as well as applications for direct CPL detection in spin optoelectronics. [ABSTRACT FROM AUTHOR]

Two-dimensional van der Waals (vdWs) heterostructures have shown great potential in the field of electronic and optoelectronic applications over the recent decade. However, the controlled preparation of high-quality vdWs heterostructures remains a great challenge ascribing to the incompatibility of different material synthesis processes. Here, we report a two-step chemical vapor deposition method for the growth of high quality WS2 on a WSe2 template with a very low temperature of ∼550 °C, where WO3 nanosheets formed in the first step are further employed as the precursor for synthesis of the top WS2 layer in the second step. Such low growth temperatures in the second step also enable the effective protection of bottom WSe2 during the WS2 growth process and, therefore, result in high-quality WSe2/WS2 heterostructures. Photoluminescence characterizations are further conducted, where significant interlayer exciton emission is observed, indicating strong interlayer coupling in the heterostructure. Based on the obtained WSe2/WS2 heterostructure, dual-channel photosensitive devices were further designed and systematically studied, where high photoresponsivity (3 A/W) as well as fast response speed (<1 ms) are obtained. The developed WO3-assisted growth technique would provide an effective reference for the controlled synthesis of high quality vdWs heterostructures and promote further applications in high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Parameter mismatches in conventional model predictive current control (MPCC) would worsen torque and THD performance. To eliminate the parameter dependence of MPCC, this letter proposes a model-free predictive current control (MFPCC) for a three-level inverter-fed interior permanent magnet synchronous motor (IPMSM). Firstly, to increase the current difference updating frequency in the diode neutral-point-clamped (NPC) three-level inverter, a synchronous updating method is proposed in a manner where the number of updated current differences during one sampling period is increased up to 6. Secondly, for the sake of computational burden alleviation, a candidate vector selection algorithm is introduced in such a way that the number of candidate vectors is reduced to only 7–9. Then, the problem of neutral-point voltage fluctuation which is inherent to the three-level NPC inverter is investigated, and a reasonable replacement method incorporating the redundancy characteristic of small vectors is developed. Finally, experimental results verify that the system robustness against mismatched parameters can be greatly enhanced by use of the proposed control scheme; meanwhile, steady-state performance and dynamic-state response of the system can be improved to some extent as well. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae is an important microorganism and is used as a cell factory for many chemicals production. When glycerol was used as the carbon source, 1,3-propanediol was the main catabolite of this bacterium. K. pneumoniae ΔtpiA lost the activity of triosephosphate isomerase and prevented glycerol catabolism through the glycolysis pathway. But this strain still utilized glycerol, and 1,2-propanediol became the main catabolite. Key enzymes of 1,2-propanediol synthesis from glycerol were investigated in detail. dhaD and gldA encoded glycerol dehydrogenases were both responsible for the conversion of glycerol to dihydroxyacetone, but overexpression of the two enzymes resulted in a decrease of 1,2-propanediol production. There are two dihydroxyacetone kinases (I and II), but the dihydroxyacetone kinase I had no contribution to dihydroxyacetone phosphate formation. Dihydroxyacetone phosphate was converted to methylglyoxal, and methylglyoxal was then reduced to lactaldehyde or hydroxyacetone and further reduced to form 1,2-propanediol. Individual overexpression of mgsA, yqhD, and fucO resulted in increased production of 1,2-propanediol, but only the combined expression of mgsA and yqhD showed a positive effect on 1,2-propanediol production. The process parameters for 1,2-propanediol production by Kp ΔtpiA-mgsA-yqhD were optimized, with pH 7.0 and agitation rate of 350 rpm found to be optimal. In the fed-batch fermentation, 9.3 g/L of 1,2-propanediol was produced after 144 h of cultivation, and the substrate conversion ratio was 0.2 g/g. This study provides an efficient way of 1,2-propanediol production from glycerol via an endogenous pathway of K. pneumoniae. Key points • 1,2-Propanediol was synthesis from glycerol by a tpiA knocked out K. pneumoniae • Overexpression of mgsA, yqhD, or fucO promote 1,2-propanediol production • 9.3 g/L of 1,2-propanediol was produced in fed-batch fermentation [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae is a bacterium that can be used as producer for numerous chemicals. Glycerol can be catabolised by K. pneumoniae and dihydroxyacetone is an intermediate of this catabolism pathway. Here dihydroxyacetone and glycerol were produced from glucose by this bacterium based a redirected glycerol catabolism pathway. Results: tpiA, encoding triosephosphate isomerase, was knocked out to block the further catabolism of dihydroxyacetone phosphate in the glycolysis. After overexpression of a Corynebacterium glutamicum dihydroxyacetone phosphate dephosphorylase (hdpA), the engineered strain produced remarkable levels of dihydroxyacetone (7.0 g/L) and glycerol (2.5 g/L) from glucose. Further increase in product formation were obtained by knocking out gapA encoding an iosenzyme of glyceraldehyde 3-phosphate dehydrogenase. There are two dihydroxyacetone kinases in K. pneumoniae. They were both disrupted to prevent an inefficient reaction cycle between dihydroxyacetone phosphate and dihydroxyacetone, and the resulting strains had a distinct improvement in dihydroxyacetone and glycerol production. pH 6.0 and low air supplement were identified as the optimal conditions for dihydroxyacetone and glycerol production by K, pneumoniae ΔtpiA-ΔDHAK-hdpA. In fed batch fermentation 23.9 g/L of dihydroxyacetone and 10.8 g/L of glycerol were produced after 91 h of cultivation, with the total conversion ratio of 0.97 mol/mol glucose. Conclusions: This study provides a novel and highly efficient way of dihydroxyacetone and glycerol production from glucose. [ABSTRACT FROM AUTHOR]

Magnesium/polytetrafluoroethylene/Viton (MTV) fuel-rich pyrolants use the atmospheric oxygen as a complementary oxidizer to sustain and alter the performance of the combustion reaction. The flame diffusion characteristics of MTV fuel-rich pyrolants in the atmospheric environment are studied by a high-speed camera (HSC). The flame temperature and combustion components are measured by using remote sensing Fourier Transform Infrared Spectrometer (FTIR). In order to obtain the combustion component distribution more accurately, an aerobic combustion model containing the oxidation reaction of the excess reactant Mg and carbonaceous species with O2 is established in this study. Eddy dissipation concept (EDC) model is applied to the numerical simulation of the three dimensional anaerobic and aerobic combustion field coupled with Realizable k-ε two-equation turbulence model. The research results show that flame temperature is mainly contributed by anaerobic combustion reaction. The flame structure obtained by the aerobic combustion model is closer to the experimental results, and the result of component distribution calculated by aerobic combustion is more consistent with characteristic spectrum. Therefore, the aerobic combustion model is more suitable for describing the actual MTV flame, and the combustion field can be divided into an anaerobic core zone and an aerobic diffusion zone. [ABSTRACT FROM AUTHOR]

Development of one-step processes combining hierarchical porous architecture with heteroatom doping control has remained a challenge. This is especially important for structure-engineered graphene materials as high performance active electrodes for energy and advanced applications. Herein, we present a facile and general approach for synthesizing patternable, nitrogen-doped and hierarchical porous graphene from graphene oxide/urea mixture using high-repetition picosecond laser in ambient air. Impressively, the highest areal capacitance of laser-induced nitrogen-doped graphene (LING) is 60.7 mF/cm2, which is about 3 times that of undoped porous graphene. After 25,000 consecutive cycles of galvanostatic charge-discharge at a current density of 10 mA/cm2, the optimized LING electrode maintained 98.7% of its original capacitance. Most importantly, the as-prepared LING electrode material has high energy and power density due to the synergistic effect of hierarchical porous structure, nitrogen-doping and engineering defects. The proposed laser one-step synthesis of LING may also be applied to other heteroatom-doped hierarchical porous graphene-based electrodes for high-performance electrochemical energy storage. This work presents an extremely facile and versatile strategy for the synthesis of defective nitrogen-doped hierarchically porous graphene as a high performance storage electrode material on self-assembled graphene oxide/urea mixture film via high-repetition picosecond laser. Image 1 [ABSTRACT FROM AUTHOR]

• Designed a combustion experiment platform that can mimic high-altitude environment. • Revealed the effect of Mg-burning particles on combustion and infrared signatures. • Gas-solid two-phase coupling effects are treated in combustion simulation. • Developed an in-house code to solve the non-isotropic radiative transfer equation. The combustion process of Mg/PTFE/Viton-based pyrotechnics exhibits a complex multiphase flow phenomenon. However, the influence mechanism of metal particles undergoing dynamic diffusion combustion in the flow field on the infrared radiation output characteristics has not yet been elucidated. Systematic experiments and numerical simulations are performed with the combustion and infrared radiation behaviors of the pyrotechnic compositions. A small-scale sealed combustion experiment platform is specially manufactured to mimic the actual ambient pressure at different cruise altitudes. An infrared thermal imager and an infrared thermometer are adopted cooperatively to diagnose the burning process. The Euler-Langrangian method is applied to mathematically describe the gas–solid two-phase interaction in the combustion flow field, and the Eddy Dissipation Concept (EDC) combustion model is employed to simulate the coupling effect of turbulence and chemical reaction in the gas-phase reaction zone. The verified Source Six-Flux (SSF) method based in-house code solves the infrared radiative transfer equation integrating the emission, absorption and scattering effects of participating media. The comparisons with the experimental results demonstrate that the computational model involving heterogeneous reactions established in this paper better approximates the realistic situation. The results reveal that the infrared radiation output capability of dispersed combustion particles in the 2.0–5.5 μm band surpasses that of high-temperature gas molecules under different environmental pressures. The infrared radiation magnitude of both the gaseous phase and the particulate phase decrease significantly with decreasing pressure. The thermal radiation of combustion particles is mainly concentrated in the near- to mid-infrared band, while its emission in the far-infrared band is relatively weak. These scientific findings provide conducive insights for lucubrating the infrared radiation mechanism of pyrotechnics under negative pressure environments, and assist in further promoting the application of MTV pyrotechnics in the field of aerospace. [ABSTRACT FROM AUTHOR]

To solve problems such as insufficient energy and effective arc burning during the injection of a working medium in a short arc discharge channel, the application of a W-Cu alloy as the electrode material in short electrical arc machining (SEAM) is explored in this paper. Using the surface roughness, material removal rate, and tool electrode wear rate as technical indices, the effects of voltage, frequency, and duty cycle on W-Cu alloy materials are studied to explore machining characteristics in SEAM. Contrast experiments on a graphite electrode were conducted using a SU8010 scanning electron microscope and energy spectrum analysis to study the erosion mechanism of the W-Cu alloy material. This paper addresses applications of copper-based composites in SEAM and provides a theoretical basis for the development of electrode materials in the SEAM. [ABSTRACT FROM AUTHOR]

Development of 3D hierarchically porous graphene (HPG) with supercapacitor performances at low cost has remained a challenge in electrochemical devices. Recently, laser engraving technology has been proposed as a promising and very useful method to inscribe self-designed electrode array directly onto polymeric substrates by instantaneously converting the starting material into few-layer graphene. Here we show HPG fabrication on commercial bakelite resulting in porous graphene embedded in polymer surface using the high repetition nanosecond fiber laser engraving under nitrogen atmosphere. The results showed that the as-prepared HPG presents a combination of interconnected macro-, meso- and micropores with a multi-modal pore size distribution. The morphologies, microstructures and their properties of HPG films can be governed by the laser processing parameters. Moreover, the HPG-based supercapacitors show outstanding electrochemical performance with specific capacitance superior to other supercapacitors reported previously. The simple, rapid and low-cost approach proposed in this work has great potential in large-scale applications of electronic and energy storage devices. [ABSTRACT FROM AUTHOR]

Development of rapid processes combining the preparation of porous structures with the control of their properties has remained a challenge. This is particularly true for applications of graphitized hierarchically porous carbon nanosheets (GHPCNs) predominantly focus on fields of energy storage and conversion materials, electronics, sensors, separation and detection. Here we report a one-step approach to transform commercial bakelite into three-dimensional high electrical conductivity GHPCNs using the high-repetition picosecond infrared laser scribing in nitrogen atmosphere. The GHPCNs with mesopores and macropores can be rapidly induced on bakelite plate by the transient laser heating due to thermal accumulation effect. Studies reveal that the in-plane topological defects of the bakelite-based GHPCNs flakes contain pentagon-heptagon structures. The local controllable laser patterning technique enables porous structures and shapes to be controlled in highly GHPCNs films with variable properties. The methodology developed here have great potential to stimulate both research and industrial interest in the development of bakelite-derived GHPCNs electronic and energy storage micro-devices. [ABSTRACT FROM AUTHOR]

• A new type of fluorine-containing oxidant BiOF was synthesized. • The n-Al/BiOF system exhibits excellent ignition and combustion properties. • The pre-ignition reaction between BiOF and n-Al promotes energy release. • The energy release of n-Al/BiOF depends on the Al-O/Al-F synergistic mechanism. The reduced diffusion distance of nano-thermite results in an exceptionally high energy release rate and intense exothermic reactions upon ignition, which has drawn significant interest from researchers in the field of energetic materials. With the deepening of research, metal fluorides are gradually favored by researchers because of their unique reaction characteristics. This paper presents the synthesis of a new fluorine-containing oxidant, BiOF, and its use in the preparation of a novel nano-thermite with n-Al. BiOF crystals exhibit a unique microscopic morphology and are interlaced into "nanoflower" microspheres, which allows for good interfacial contact between the oxidant and fuel during the recombination process. The resulting n-Al/BiOF system displays excellent ignition and combustion performance, with a combustion temperature higher than the boiling point of its main combustion products, AlF 3 and Bi. Compared with n-Al/CuO and n-Al/MoO 3 systems, n-Al/BiOF exhibits a higher flame propagation rate under confinement. In addition, the ignition threshold of the n-Al/BiOF system is also smaller than that of the n-Al/CuO and n-Al/MoO 3 systems. Furthermore, the paper examines the reaction mechanism of the n-Al/BiOF system through thermal reaction path analysis and combustion and thermal analysis product characterization. The paper discovers a "pre-ignition" reaction mechanism before the ignition temperature, where the strongly electronegative fluorine in BiOF corrodes the Al 2 O 3 shell, promoting the release of aluminum energy. The synergistic and effective interaction between oxygen, fluorine, and fuel aluminum in the n-Al/BiOF system results in efficient energy release performance, making BiOF a promising candidate for n-Al based reactive materials in propellants, explosives, and pyrotechnic products. [ABSTRACT FROM AUTHOR]

• Eutectic silicon makes the combustion of Al-Si/CuO more stable than Al/CuO. • The increased solid phase products of Al-Si/CuO guarantees good ignition ability. • The eutectic silicon leads to an advanced and enhanced heat release of Al-Si alloy. • Al-Si/CuO thermites ignite Mg/Teflon/Viton (MTV) column faster than Al/CuO. The unstable energy release efficiency hinders the application of Al/CuO metastable intermixed composites (MICs) in pyrotechnic applications to some extent. To overcome this issue, systematic experiments of Aluminum-Silicon (Al-Si) alloy-thermites with different Si content (12 wt% and 20 wt%) have been investigated in the context of regulating the energy release process. Optical diagnosis methods were applied synchronously to measure the flame propagation velocity and temperature field variation. Scanning electron microscopy and differential scanning calorimetry were used to observe the morphology and analyze the thermal process. Results indicated that the introduction of silicon significantly stabilized the combustion process of Al-Si/CuO due to the fewer gas-phase products and slower reaction rate of Si with CuO, while the flame temperature changed little. Excess silicon wafer blocks observed by SEM on Al-20Si led to an enhanced transport of oxygen and fuel. This explained the abnormal reactivity of hypereutectic alloy. The total heat releases of Al-20Si and Al-12Si were respectively enhanced by 110.2% and 93.1% in comparison with that of Al under DSC tests. Infrared temperature measurement of the Mg/Teflon/Viton (MTV) column revealed that Al-12Si and Al-20Si alloy thermites ignited MTV column 569.06 and 540.48 ms faster than Al/CuO, respectively, as the energy output mainly existed in the form of high-temperature residues. These improvements are attributed to the synergistic effect of the reactivity of silicon and aluminum, as well as the phase change during reaction which provides a controllable energy release process of alloy thermite and a better ignition performance. These findings are expected to facilitate the development of the nature of Al alloys and are especially promising for the thermite technology driven by reliable energy release rates. [ABSTRACT FROM AUTHOR]

This work mainly focuses on exploring carbon coated ε-MnO 2 (ε-MnO 2 /C) with 3D hierarchical structures for degradation of gaseous toluene under visible light. Influence of C-coating on surface adsorption, visible-light activity and photocatalytic activities of C-coated MnO 2 have been investigated. The results indicate that the C-coating behave as the adsorption and electron-transfer system, and the resulting C-coated ε-MnO 2 could extend the optical response from UV to visible light region, which can generate more electron − hole pairs. The photocatalyst ε-MnO 2 /0.45C exhibited excellent visible-light photocatalytic activities, with degradation rate of toluene up to 87.34% in 70 min, but no photocatalytic activity could be observed for the pure ε-MnO 2 . The PL spectra and photocurrent response results indicate that the composite structure can not only enhance the utilization of visible light but also consequently reduce electron (e − )-hole (h + ) pair recombination, which improve the photocatalytic efficiency of the composite photocatalyst. This work provides a facile and economic approach for fabricating photocatalysts with high efficiency for degradation of VOCs under visible light at room temperature. [ABSTRACT FROM AUTHOR]

The energy performance of nanothermites in aqueous conditions is commonly restricted by the rapid heat dissipation and corrosion of nano-Al. Here we report studies on the fabrication and submerged ignition for the super-hydrophobic nanothermite film based upon the Co 3 O 4 /Al core/shell nanowires (NWs). The Co 3 O 4 NWs arrays, which are synthesized using a facile hydrothermal-annealing method, serve as templates for the deposition of Al shells by magnetron sputtering. The super-hydrophobic surface is subsequently realized by the fluoroalkylsilane coating. The tests of the laser-induced underwater ignition reveal that the super-hydrophobic modification effectively could lead to the ignition of the nanothermite film. Furthermore, the anti-aging behaviors of the obtained super-hydrophobic nanothermite film in aqueous conditions are investigated in detail to compare the heat-release and ignition characteristics at different submersion times. Impressively, the resultant super-hydrophobic composite could still hold about 50% of the original energy even after an underwater storage of 2 days. [ABSTRACT FROM AUTHOR]

Metastable intermolecular complexes (MICs), which have exceptional energy density and reactivity, have drawn considerable attention in the field of energetic materials. In this work, a facile cryogel method is explored for fabricating n-Al/PVDF energetic films with the controllable tuning of reactivity and laser sensitivity. The microstructure of the films was transformed from dense packing to 3D cross-linking by adjusting the process parameters. With the formation of the porous structure, the energetic film exhibits a higher energy release rate (the flame propagation speed increases from 8.2 cm∙s−1 to 13.5 cm∙s−1) and a lower laser ignition delay (from 33.6 ms to 10.1 ms). The mechanisms underlying the altered reactivity are discussed in depth to provide insights into understanding changes in energy properties. This work provides an effective and facile strategy for realizing the tunability of the reactivity and sensitivity of n-Al/PVDF composites, which will aid to broaden their use in micro-transducers. [Display omitted] • Facile cryogel method for fabricating n-Al/PVDF energetic films. • Effective strategy for realizing the tunability of the reactivity of n-Al/PVDF. • Influence of microstructure on laser-material interface interaction. • Understanding the structure-activity relationship from the perspective of competing reaction pathways. [ABSTRACT FROM AUTHOR]

• Designed a combustion experiment platform that can simulate high-altitude environment. • Revealed the intrinsic effect of pressure on the fluorination and oxidation of Mg. • Provided further insight into micro-scale combustion process of Mg particles. • Heterogeneous condensation reactions are innovatively treated in combustion simulation. The exploration of condensed combustion products (CCPs) is essential to reveal the ignition, combustion, and infrared radiation mechanisms of Mg-based (Magnesium/polytetrafluoroethylene/Viton) solid fuels that have been considerably employed in the field of aerospace. Systematic experiments and numerical simulations are performed with the physicochemical properties (including morphology, element distribution, phase composition and particle size distribution) and flow field distribution characteristics of CCPs, respectively. The effects of formulation and pressure on the combustion behaviors of pyrotechnic compositions are thoroughly investigated based on thermal analysis measurements, laser ignition, optical diagnosis and CCPs collection. The results demonstrated that the major solid products for all cases are MgF 2 agglomerates and MgO smoke oxide particles (SOPs). Increasing the Mg content in the formulation is simultaneously beneficial for the reduction of large agglomerates and SOPs. As the pressure is decreased from 0.1 MPa to 0.02 MPa, the volume weighted mean diameter of CCPs increases significantly due to the decrease in burning rate. The numerical model established in this paper better approximates the realistic combustion process by coupling the heterogeneous condensation reactions, and is adopted to predict the distribution of CCPs in the combustion flow field under different experimental conditions. Numerical results reveal that the MgF 2 is mainly distributed in the anaerobic combustion core zone immediately above the burning surface, while MgO is located in the peripheral aerobic combustion diffusion zone. The negative pressure environment has more profound influence on the oxidation reaction of Mg than fluorination reaction. The scientific findings are expected to facilitate the development of more complete combustion and infrared radiation models, while theoretically providing in-depth guidance for the increasing military and civilian application of Mg-based solid fuels. [ABSTRACT FROM AUTHOR]

• Designed a small-scale negative pressure combustion experiment system. • Revealed the effect of pressure on flame structure and temperature. • Demonstrated the pressure sensitivity of the burning rate under 0.02–0.1 MPa. • Predicted the combustion products distribution characteristics. The present study is devoted to comprehensively evaluating the combustion performance of Mg-based (Magnesium/polytetrafluoroethylene/Viton) solid fuels in high-altitude operating environments. A small-scale sealed CO 2 laser ignition experiment system is designed to produce different negative pressure environments. A high-speed camera (HSC) and an infrared thermal imager are used to cooperatively capture the burning process. The results obtained demonstrate that the area of the flame core zone and the flame temperature increase significantly as the pressure increases. It is conducive to the heat feedback of the gas phase reaction zone to the solid phase heating zone, resulting in an increase in the burning rate. As the Mg content increases, the flame temperature is decreased and the burning rate is increased. The burning rate for the Mg-based solid fuels is found to increase monotonically with ambient pressure and to follow the Vieille's law in the pressure range of 0.02–0.1 MPa. Based on the experiment, a three-dimensional combustion-flow coupling solution model is established including the detailed aerobic combustion reaction kinetic model and the eddy dissipation concept (EDC) model. Numerical simulation results reveal that the content of incompletely reacted Mg increases as the pressure decreases. Conversely, the decreasing behavior of oxygen partial pressure at low pressure reduces the probability of reaction of Mg with O 2 , resulting in a dramatical decrease in the mass fraction of MgO. The scientific findings provide useful insight for the deep understanding of the combustion behavior of Mg-based solid fuels, and support for the increasing demands for both military and civilian applications. [ABSTRACT FROM AUTHOR]

Abstract: The thermal properties and combustion characteristics of KClO4/Mg–50%Al, KClO4/Mg–50%Al with additives such as nitrocellulose (NC), urotropine and guanidine nitrate (GN) were studied experimentally using differential thermal analysis (DTA) and thermogravimetry (TG) and closed bomb experiments. The results of DTA–TG analysis revealed that additives could affect thermal stability and the decomposition temperature of KClO4/Mg–50%Al alloy. The order of the ignition temperatures of mixtures (T i) is KP/Mg–50%Al/urotropine (2#, 557.7°C)>KP/Mg–50%Al/GN(3#, 553.6°C)>KP/Mg–50%Al (1#, 538.8°C)>KP/Mg–50%Al/NC (4#, 536.5°C). On the other hand, the results of the closed bomb experiments confirm that the combustion pressures were all increased with the addition of additives. The ignition delay times of these mixtures are in the order KClO4/Mg–50%Al (1#)>KClO4/Mg–50%Al/GN (3#)>KClO4/Mg50%Al/NC (4#)>KClO4/Mg–50%Al/urotropine (2#). [ABSTRACT FROM AUTHOR]

• CFO/Al/Bi 2 O 3 is formed by long-range electrostatic force and covalent interactions. • CFO/Al/Bi 2 O 3 used as energetic electric-thermal conversion component. • Replacement of the Ni-Cr or SCB to solve the problems caused by film interfaces. • To detonate RDX reliably without other bridges. Carbon fiber is used to construct an energy conversion component with the purpose of high reliability, safety and potential application in micro size. The carbon fiber oxidant (CFO) is endowed as the carrier for the assembly of CFO/Al/Bi 2 O 3 while long-range electrostatic force and covalent interactions are analyzed as the main force. The self-assembly can function with a voltage as low as 15.34 V and can detonate RDX successfully without using primary explosives and traditional bridge film unit. The ignition mechanism is deduced that carbon fibers have a transient high conductivity when the voltage is charged. The one-dimensional structure and micro-size make the puncture easily and reliably. Moreover, the integration of Al/Bi 2 O 3 enhanced its initiation power and reliability. The research broadens the understanding of carbon fiber as one-dimensional material, and more applications are expected in this new field by considering the variety of carbon fiber size, different sorts of reactive materials and so on. [ABSTRACT FROM AUTHOR]