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Nickel-rich layered Li transition metal oxides are the most promising cathode materials for high-energy-density Li-ion batteries. However, they exhibit rapid capacity degradation induced by transition metal dissolution and structural reconstruction, which are associated with hydrofluoric acid (HF) generation from lithium hexafluorophosphate decomposition. The potential for thermal runaway during the working process poses another challenge. Separators are promising components to alleviate the aforementioned obstacles. Herein, an ultrathin double-layered separator with a 10 μm polyimide (PI) basement and a 2 μm polyvinylidene difluoride (PVDF) coating layer is designed and fabricated by combining a non-solvent induced phase inversion process and coating method. The PI skeleton provides good stability against potential thermal shrinkage, and the strong PI–PVDF bonding endows the composite separator with robust structural integrity; these characteristics jointly contribute to the extraordinary mechanical tolerance of the separator at elevated temperatures. Additionally, unique HF-scavenging effects are achieved with the formation of –CO···H–F hydrogen bonds for the abundant HF coordination sites provided by the imide ring; hence, the layered Ni-rich cathodes are protected from HF attack, which ultimately reduces transition metal dissolution and facilitates long-term cyclability of the Ni-rich cathodes. Li||NCM811 batteries (where “NCM” indicates LiNixCoyMn1−x−yO2) with the proposed composite separator exhibit a 90.6% capacity retention after 400 cycles at room temperature and remain sustainable at 60 °C with a 91.4% capacity retention after 200 cycles. By adopting a new perspective on separators, this study presents a feasible and promising strategy for suppressing capacity degradation and enabling the safe operation of Ni-rich cathode materials.

In the field of labor protection, the real-time monitoring of workers’ physical health status has received a lot of attention. Because breathing contains a lot of physiological information, the development of wearable devices with sensing functions for monitoring the wearer’s respiratory status has become a research hotspot. Traditional commercial respiratory monitoring devices are expensive, bulky, and not easy to be carried, limiting their use in front-line production sites, such as high dust mass concentration mines’ operating environments. In view of this situation, based on the piezoelectric properties of polyvinylidene fluoride (PVDF), a flexible PVDF nanofiber membrane with sensing properties was prepared using electrospinning technology. The high permeability carbon fiber felt and PVDF nanofiber membrane were designed as a sandwich structure. The sensing module was embedded in the mask. The sensor module converted the mechanical energy generated by the respiratory airflow into electrical energy. Through the collection and analysis of electrical signal data, the real-time monitoring of respiratory intensity and respiratory frequency was completed. The results show that the piezoelectric signals generated by the mask embedded with the sensing module are significantly different under different breathing states. Under the three breathing states of low intensity (15 L/min), medium intensity (50 L/min) and high intensity (85 L/min), the output piezoelectric voltage peaks are 300, 700 and 1 100 mV, respectively, and the frequency of voltage peaks is 18, 16 and 14 times/min, respectively. Therefore, based on the analysis of the peak voltage and its frequency of the piezoelectric signal, the real-time monitoring of respiratory parameters such as the wearer's respiratory intensity and respiratory frequency can be realized. In addition, the piezoelectric properties of PVDF nanofiber membranes were determined to be related to the content of β-phase crystals by XRD, FT-IR, TG and other analysis methods, which provided a basis for further improving the piezoelectric properties of PVDF nanofiber membranes. The developed mask with sensing function can be used for the real-time respiratory monitoring of mine workers’ working conditions, and the feedback to managers when workers’ working conditions are abnormal to facilitate some timely treatment measures.

Objective To achieve supervision and management of the whole business process of blood center, raise productivity and ensure blood quality by enabling blood center managers comprehensively grasp the key business operation situation of the whole process at anytime and anywhere. Methods A whole business process supervision and management system was established covering background of preparation, business scope, content of position supervision and management, overall framework design, interface design of management and supervision management, physical database design, program development and online debugging, and was integrated with the blood bank management information system. The display and management were through a mobile APP to record key indicators of business process from blood collection to blood supply timely and comprehensively. Statistical analysis was conducted on total collection volume, total preparation volume and total supply volume, as well as discarding rate of test unqualified and of non-test unqualified (lipemic blood excluded) in 2023 and 2022. Results We established a mobile APP based on a blood bank management information system for business supervision and management of whole process, and achieved management by phones. After its implementation in 2023, the total collection volume, total preparation volume and total supply volume in 2023 were all higher than those in 2022, with growth rates of 5.88% (13 247/225 454 U), 4.73% (24 156/510 698 U), and 6.70% (34 814/519 914 U), respectively. The discarding rate in 2023 was lower than that in 2022 (0.54%, 2 868/534 854 U) vs (0.60%, 3 047/510 698 U) (P

The safe operation of high-speed rail running gear is crucial, as fault diagnosis can effectively prevent potential risks and ensure the smooth operation of the train. The Belief Rule Base (BRB) method has demonstrated excellent performance in complex system modeling. However, during the optimization process, BRB may lead to a “combinatorial explosion” of rules within the model, resulting in a loss of model interpretability and an increase in complexity. To address this, a Multidimensional Belief Rule Base (MBRB) fault diagnosis method is proposed. By optimizing the structure and parameters, the interpretability of the model is enhanced, and its complexity is reduced. Specifically, the model inputs are decomposed into multiple dimensions for analysis, and then the MBRB rules are updated using the Projection Covariance Matrix Adaption Evolution Strategy (P-CMA-ES), increasing the model’s interpretability and accuracy. Finally, the effectiveness of this method is validated through an example of high-speed rail running gear.

Substantial evidence suggests that all types of water, such as drinking water, wastewater, surface water, and groundwater, can be potential sources of Helicobacter pylori (H. pylori) infection. Thus, it is critical to thoroughly investigate all possible preconditioning methods to enhance the recovery of H. pylori, improve the reproducibility of subsequent detection, and optimize the suitability for various water types and different detection purposes. In this study, we proposed and evaluated five distinct preconditioning methods for treating water samples collected from multiple urban water environments, aiming to maximize the quantitative qPCR readouts and achieve effective selective cultivation. According to the experimental results, when using the qPCR technique to examine WWTP influent, effluent, septic tank, and wetland water samples, the significance of having a preliminary cleaning step becomes more evident as it can profoundly influence qPCR detection results. In contrast, the simple, straightforward membrane filtration method could perform best when isolating and culturing H. pylori from all water samples. Upon examining the cultivation and qPCR results obtained from groundwater samples, the presence of infectious H. pylori (potentially other pathogens) in aquifers must represent a pressing environmental emergency demanding immediate attention. Furthermore, we believe groundwater can be used as a medium to reflect the H. pylori prevalence in a highly populated community due to its straightforward analytical matrix, consistent detection performance, and minimal interferences from human activities, temperature, precipitation, and other environmental fluctuations.

Background and purpose: Obesity among children and adolescents continues to increase globally, and it is important to determine the factors associated with obesity among adolescents for the prevention and reduction of obesity. The purpose of this study is to understand the factors associated with the increase in the obesity rate among adolescents, providing a reference basis for the development of projects aimed at promoting adolescent health. Methods: Using the raw data of 2021 adolescent health behavior online survey, this study analyzed demographic sociological factors, mental health, exercise habits, health behaviors and other categorical variables, and conducted the frequency, χ2 test for the difference in the proportion of obese and non-obese. According to the hierarchy model of obesity-related variables, binary logistics regression is used for multivariate analysis. This study used the original data of the 2021 Youth Health Behavior Online Survey, and performed frequency, χ2 tests on the differences in the proportion of obese and non-obese for categorical variables such as demographic sociological factors, mental health, exercise habits, and health behaviors. Multivariate analysis was performed using binary logistic regression based on hierarchical models of obesity-related variables. Results: The obesity rate among Korean adolescents was 18.25 %. The obesity risk for females was reduced by 0.344 times compared to males (95 % CI = 0.327–0.361, p

To meet the practical demand of wearable/portable electronics, developing high-efficiency and durable multifunctional catalyst and in-situ assembling catalysts into electrodes with flexible features are urgently needed but challenging. Herein, we report a simple route to fabricate bendable multifunctional electrodes by in-situ carbonization of metal ion absorbed polyaniline precursor. Alloy nanoparticles encapsulated in graphite layer are uniformly distributed in the N-doping carbon nanorod skeleton. Profiting from the favorable free-standing structure and the cooperative effect of metallic nanoparticles, graphitic layer and N doped-carbon architecture, the trifunctional electrodes exhibit prominent activities and stability toward HER, OER and ORR. Notably, due to the protection of carbon layer, the electrocatalysts show the reversible catalytic HER/OER properties. The overall water splitting device can continuously work for 12 h under frequent exchanges of cathode and anode. Importantly, the bendable metal air batteries fabricated by self-supported electrode not only displays the outstanding battery performance, achieving a decent peak power density (125 mW cm−2) and exhibiting favorable charge-discharge durability of 22 h, but also holds superb flexible stability. Specially, a lightweight self-driven water splitting unit is demonstrated with stable hydrogen production.

Drying is a complicated physical process which involves simultaneous heat and mass transfer in the removal of solvents inside propellants. Inappropriate drying techniques may result in the formation of a hard skin layer near the surface to block the free access of most solvent through for long stick propellants with large web thickness, which lead to lower drying efficiency and worse drying quality. This study aims to gain a comprehensive understanding of drying process and clarify the mechanism of the blocked layer near the propellant surface. A new three-dimensional coupled heat and mass transfer (3D-CHMT) model was successfully developed under transient conditions. The drying experiment results show that the 3D-CHMT model could be applied to describe the drying process well since the relative error of the content of solvent between simulation and experiment values is only 5.5%. The solvent behavior simulation demonstrates that the mass transfer process can be divided into super-fast (SF) and subsequent minor-fast (MF) stages, and the SF stage is vital to the prevention of the blocked layer against the free access for solvent molecules inside propellant grains. The effective solvent diffusion coefficient (Deff) of the propellant surface initially increases from 3.4 × 10−6 to 5.3 × 10−6 m2/s as the temperature increases, and then decreases to 4.1 × 10−8 m2/s at 60–100 min. The value of Deff of surface between 0–1.4 mm has a unique trend of change compared with other regions, and it is much lower than that of the internal at 100 min under simulation conditions. Meanwhile, the temperature of the propellant surface increases rapidly at the SF stage (0–100 min) and then very slowly thereafter. Both the evolution of Deff and temperature distribution demonstrate that the blocked layer near the propellant surface has been formed in the time period of approximately 0–100 min and its thickness is about 1.4 mm. To mitigate the formation of blocked layer and improve its drying quality of finial propellant products effectively, it should be initially dried at lower drying temperature (30–40 °C) in 0–100 min and then dried at higher drying temperature (50–60 °C) to reduce drying time for later drying process in double base gun propellants. The present results can provide theoretical guidance for drying process and optimization of drying parameters for long stick propellants with large web thickness.

The prediction of the health status of critical components is an important influence in making accurate maintenance decisions for rotating equipment. Since vibration signals contain a large amount of fault information, they can more accurately describe the health status of critical components. Therefore, it is widely used in the field of rotating equipment health state prediction. However, there are two major problems in predicting the health status of key components based on vibration signals: (1) The working environment of rotating equipment is harsh, and if only one feature in the time or frequency domain is selected for fault analysis, it will be susceptible to harsh operating environments and cannot completely reflect the fault information. (2) The vibration signals are unlabeled time series data, which are difficult to accurately convert into the health status of key components. In order to solve the above problems, this paper proposes a combined prediction model combining a bidirectional long- and short-term memory network (BiLSTM), a self-organizing neural network (SOM) and particle swarm optimization (PSO). Firstly, the SOM is utilized to fuse the fault characteristics of multiple vibration signals of key components to obtain an indicator (HI) that can reflect the health status of rotating equipment and to also compensate for the vulnerability of single signal characteristics in the time or frequency domain to environmental influences. Secondly, the K-means clustering method is employed to cluster the health indicators and determine the health state, which solves the problem of determining the health of a component from unsupervised vibration signal data which is quite difficult. Finally, the particle swarm optimized BiLSTM model is used to predict the health state of key components and the bearing dataset from the IEEE PHM 2012 Data Challenge verifies the method’s effectiveness and validity.

This paper addressed three major challenges in the customization of mixed propellant charges: optimal design, performance simulation, and manufacturing. Based on parametric modeling software Grasshopper, parametric models of propellants with highly complex geometries were endowed with combustion properties of multiple formulations, coupled with rapidly changing burning rate-pressure field during iterative combustion to achieve visual and integrated simulation of burning surface regression, form function, and combustion performance of mixed charges, providing convenient theoretical guidance for structural optimization design of customized strategies. Customized zones designed with complex geometries and multiple formulations co-constructed in one propellant were prepared by multi-material additive manufacturing techniques. Different customized zones of one or more propellants were superimposed in the design sequence to customize the combustion performance. Mixed charges for three cases of burning surface, burning rate, and joint control were discussed. The simulation results matched well with the experimental results, including the progressively random perforated combustion, variation of burning rate pressure exponent, and superimposed combustion of single and multiple charges with different customized zones. As an advanced engineering strategy urgently needed in chemical engineering, this work not only opens the door to matching performance simulation-driven design with MM-AM technologies but also serves as an efficient and common customization strategy from design to manufacture.

Recently, a novel kind of thermal plastic energetic cellulose binder nitrate glycerol ether cellulose (NGEC) exhibits promising application in enhancing the mechanical property of propellants. In this study, a series of NGEC-based core-shell nanoenergetic composites were prepared by electrostatic spray technology, including RDX@NGEC, HMX@NGEC, and CL-20@NGEC. The findings revealed that NGEC was coated uniformly on the surface of energetic crystals and presented favorable spherical morphology. The thermal decomposition demonstrated that the polymorphic phase transition of HMX and CL-20 almost disappeared, and the activation energy (Ea) was also calculated. Comparing with original energetic crystals, the Ea of RDX@NGEC (133.44 kJ/mol) and HMX@NGEC (326.65 kJ/mol) were increased by 11.39 kJ/mol and 38.58 kJ/mol, respectively, while that of CL-20@NGEC (155.59 kJ/mol) was decreased by 76.18 kJ/mol. Finally, the impact sensitivity has been reduced dramatically. Hence, this fabrication strategy of NGEC-based nanoenergetic composites has profound basic theory research significance and may provide promising application propellants.

In the green synthesis reaction of adipic acid, the oxidant H2O2 undergoes exothermic decomposition easily and the high exothermic amount of the reaction can easily lead to thermal runaway. This study carries out calorimetric experiments on the green synthesis reaction of adipic acid, studies the effect of the stabilizer ethylenediaminetetraacetic acid (EDTA) on the safety of the synthesis reaction, and further explores the effect of EDTA on the Na2WO4-catalyzed decomposition reaction of H2O2 under the conditions of continuous flow, and develops the microchannel continuous flow process of green synthesis of adipic acid containing EDTA, in order to provide theoretical support for the improvement of intrinsic safety of green synthesis of adipic acid.

Abstract Zn‐N‐C possesses the intrinsic inertia for Fenton‐like reaction and can retain robust durability in harsh circumstance, but it is often neglected in oxygen reduction reaction (ORR) because of its poor catalytic activity. Zn is of fully filled 3d104s2 configuration and is prone to evaporation, making it difficult to regulate the electronic and geometric structure of Zn center. Here, guided by theoretical calculations, five‐fold coordinated single‐atom Zn sites with four in‐plane N ligands is constructed and one axial O ligand (Zn‐N4‐O) by ionic liquid‐assisted molten salt template method. Additional axial O not only triggers a geometry transformation from the planar structure of Zn‐N4 to the non‐planar structure of Zn‐N4‐O, but also induces the electron transfer from Zn center to neighboring atoms and lower the d‐band center of Zn atom, which weakens the adsorption strength of *OH and decreases the energy barrier of rate determining step of ORR. Consequently, the Zn‐N4‐O sites exhibit improved ORR activity and excellent methanol tolerance with long‐term durability. The Zn‐air battery assembled by Zn‐N4‐O presents a maximum power density of 182 mW cm−2 and can operate continuously for over 160 h. This work provides new insights into the design of Zn‐based single atom catalysts through axial coordination engineering.

Abstract Proton exchange membrane fuel cells (PEMFCs) have become a major component of current clean energy technologies. Accounting for nearly half the cost of a commercial fuel cell stack, Pt‐based catalysts are the main choices for both anode and cathode in PEMFCs. However, catalytical activity and operating life of Pt‐based catalysts are still unsatisfactory. High cost and scarcity of Pt further hinder the development of PEMFCs. Constructing core‐shell structure for Pt‐based catalysts is a promising strategy to enhance the catalytic activity and reduce the cost. In this review, we overview recent advances in Pt‐based core‐shell catalysts according to catalytic reaction types involved in PEMFCs. Furthermore, we discuss the working principle of core‐shell catalysts from the perspective of coupling between core and shell. In the end, we conclude the recent progress and discuss the future developments and facing challenges.

Abstract Ultrathin, lightweight, and flexible aligned single-walled carbon nanotube (SWCNT) films are fabricated by a facile, environmentally friendly, and scalable printing methodology. The aligned pattern and outstanding intrinsic properties render “metal-like” thermal conductivity of the SWCNT films, as well as excellent mechanical strength, flexibility, and hydrophobicity. Further, the aligned cellular microstructure promotes the electromagnetic interference (EMI) shielding ability of the SWCNTs, leading to excellent shielding effectiveness (SE) of ~ 39 to 90 dB despite a density of only ~ 0.6 g cm−3 at thicknesses of merely 1.5–24 µm, respectively. An ultrahigh thickness-specific SE of 25 693 dB mm−1 and an unprecedented normalized specific SE of 428 222 dB cm2 g−1 are accomplished by the freestanding SWCNT films, significantly surpassing previously reported shielding materials. In addition to an EMI SE greater than 54 dB in an ultra-broadband frequency range of around 400 GHz, the films demonstrate excellent EMI shielding stability and reliability when subjected to mechanical deformation, chemical (acid/alkali/organic solvent) corrosion, and high-/low-temperature environments. The novel printed SWCNT films offer significant potential for practical applications in the aerospace, defense, precision components, and smart wearable electronics industries.

Molybdenum disulfide (MoS2), which generally possesses a graphene-like two-dimensional layered structure and unique physicochemical and electrical properties, is an emerging material to next-generation high-energy-density storage beyond the reach of current anode technologies. However, pristine layered MoS2 suffers from low conductivity and poor cycle stability, thus hindering its development in lithium ion batteries (LIBs). Herein, we prepare a self-assembled MoS2 nano-particle structure induced by 1-dodecanethiol (DDT) through a bottom-up approach. The superior rate and high capacity of LIBs are attributed to the large specific surface area (64.29 m2 g−1) and short internal distance, giving rise to the pseudocapacitance and diffusion-controlled process in the electrochemical behavior, respectively. In situ Raman, Density Function Theory (DFT) calculation and X-ray photoelectron spectroscopy verify the conversion from MoS2 to Mo in the lithiation process, and the strong binding energy between Mo and LiF contributes to a stable solid electrolyte interphase during Li+ intercalation/de-intercalation reversible process. The cell using MoS2 nano-particles anode delivers a preferable discharge capacity of 600 mA h g−1 after 1000 cycles at the current density of 1.0 A g−1 than commercial and recently reported MoS2 anodes. This work inspires the development of nano-structure for resistance to large-volume expansion/shrinkage and high stability.

Co-pyrolysis technology containing biomass offers remarkable advantages in reducing NOx emissions economically and efficiently. In this work, it was innovatively introduced to solve the problem of excessive NOx emission during the incineration of waste energetic materials (EMs). The kinetics and NOx emission characteristics of waste double-base propellant (DP), pine sawdust (PS), and their mixtures with different ratios during pyrolysis were investigated by thermogravimetric analysis and fixed-bed experiments. The results showed that there was a significant interaction between DP and PS. Kinetic analysis by Friedman and Kissinger-Akahira-Sunose (KAS) methods demonstrated that the average activation energies of the mixtures with different ratios were smaller than that of DP, indicating that the addition of PS improved the reactivity of co-pyrolysis. In addition, the fixed-bed experiment determined that the lowest NOx emission was achieved during DP pyrolysis alone at 900 ℃. Co-pyrolysis at this temperature was found to have synergistic effects of reduced NOx emissions for different ratios of mixtures. The best synergistic effect was achieved at the mixing ratio of 60 wt% DP and 40 wt% PS, resulting in a 72.11 % reduction in actual NOx emissions compared to the expected value. This study provides a new direction and powerful data support for the clean, efficient and economic treatment of waste EMs, especially for practical engineering strategies.

Abstract After the spread of COVID-19, surgical masks became highly recommended to the public. They tend to be handled and used multiple times, which may impact their performance. To evaluate this risk, surgical masks of Type IIR were submitted to four simulated treatments: folding, ageing with artificial saliva or sweat and washing cycles. The air permeability, mechanical integrity, electrostatic potential, and filtration efficiency (FE) of the masks were measured to quantify possible degradation. Overall, air permeability and mechanical integrity were not affected, except after washing, which slightly degraded the filtering layers. Electrostatic potential and FE showed a strong correlation, highlighting the role of electrostatic charges on small particle filtration. A slight decrease in FE for 100 nm particles was found, from 74.4% for the reference masks to 70.6% for the mask treated in saliva for 8 h. A strong effect was observed for washed masks, resulting in FE of 46.9% (± 9.5%), comparable to that of a control group with no electrostatic charges. A dry store and reuse strategy could thus be envisaged for the public if safety in terms of viral and bacterial charge is ensured, whereas washing strongly impacts FE and is not recommended.

Classifying and identifying surface defects is essential during the production and use of aluminum profiles. Recently, the dual-convolutional neural network(CNN) model fusion framework has shown promising performance for defects classification and recognition. Spurred by this trend, this paper proposes an improved dual-CNN model fusion framework to classify and identify defects in aluminum profiles. Compared with traditional dual-CNN model fusion frameworks, the proposed architecture involves an improved fusion layer, fusion strategy, and classifier block. Specifically, the suggested method extracts the feature map of the aluminum profile RGB image from the pre-trained VGG16 model's pool5 layer and the feature map of the maximum pooling layer of the suggested A4 network, which is added after the Alexnet model. then, weighted bilinear interpolation unsamples the feature maps extracted from the maximum pooling layer of the A4 part. The network layer and upsampling schemes ensure equal feature map dimensions ensuring feature map merging utilizing an improved wavelet transform. Finally, global average pooling is employed in the classifier block instead of dense layers to reduce the model's parameters and avoid overfitting. The fused feature map is then input into the classifier block for classification. The experimental setup involves data augmentation and transfer learning to prevent overfitting due to the small-sized data sets exploited, while the K cross-validation method is employed to evaluate the model's performance during the training process. The experimental results demonstrate that the proposed dual-CNN model fusion framework attains a classification accuracy higher than current techniques, and specifically 4.3% higher than Alexnet, 2.5% for VGG16, 2.9% for Inception v3, 2.2% for VGG19, 3.6% for Resnet50, 3% for Resnet101, and 0.7% and 1.2% than the conventional dual-CNN fusion framework 1 and 2, respectively, proving the effectiveness of the proposed strategy.

Abstract Lithium‐ion batteries (LIBs) have become star products in wireless electronic equipment, new energy vehicles and many other fields due to their advantages of high energy density, light weight, good stability, high charging‐discharging efficiency, long service life and environmental friendliness. The separator is an indispensable part of batteries that does not participate in electrochemical reactions, separating the anode and cathode. It has a microporous structure, which can store electrolyte and allow ions to transfer freely. Poly(vinylidene fluoride) (PVDF)‐based separators are characterized by strong polarity, high dielectric constant, stable electrochemical performance, excellent tensile properties and mechanical strength, favorable thermal stability and wettability. Therefore, they are proposed to be potential candidates for novel separators in the field of LIBs. This review introduces the recent researches and advances in PVDF‐based separators for LIBs, with the characterizations and requirements for separators. It is mainly divided into the two types including monolayer and multilayer separators. Furthermore, the performance of the PVDF‐based separators is summarized, and the challenges and prospects in their practical application are briefly analyzed.

Abstract In order to investigate the thermal decomposition kinetics and mechanism of nitrocellulose (NC) based nitramine explosives nanocomposite energetic materials, this work prepares NC/RDX (cyclotrimethylenetrinitramine), NC/HMX (cyclotetramethylenetetranitramine), and NC/CL‐20 (hexanitrohexaazaisowurtzitane) composites by a combined sol‐gel and the freeze‐drying technology. The structure is systematically investigated and the results reveal that the explosive particles are dispersed, filled, or embedded homogenously in the gel matrix of NC, thereby restricting the crystal growth of RDX, HMX, CL‐20 particles to coarse and achieving submicron/nanometer. The thermal analysis of composites exhibits much lower peak temperature compared with raw explosive crystal, furthermore, the activation energy (Ea) of composites is also lower than that of both NC and explosives. Hence, the unique structure of NC gel matrix embedded explosives inside demonstrated different mechanism of decomposition. Concretely, the rupture of the H‐NCO = O bond in the cross‐linked structure is detected firstly, subsequently, the macromolecular chains’ scission site of gel firstly occurs at ‐C‐O‐C‐ in the ring, and then the scission of ‐NO2 (from NC or explosive crystals) bonds happened. Hence, this study may provide promising fabrication strategy and basic theory for the application of NC‐based nanocomposite energetics in high‐energy propellants and explosives.

SARS-CoV-2 spreads via droplets, aerosols, and smear infection. From the beginning of the COVID-19 pandemic, using a facemask in different locations was recommended to slow down the spread of the virus. To evaluate facemasks' performance, masks' filtration efficiency is tested for a range of particle sizes. Although such tests quantify the blockage of the mask for a range of particle sizes, the test does not quantify the cumulative amount of virus-laden particles inhaled or exhaled by its wearer. In this study, we quantify the accumulated viruses that the healthy person inhales as a function of time, activity level, type of mask, and room condition using a physics-based model. We considered different types of masks, such as surgical masks and filtering facepieces (FFPs), and different characteristics of public places such as office rooms, buses, trains, and airplanes. To do such quantification, we implemented a physics-based model of the mask. Our results confirm the importance of both people wearing a mask compared to when only one wears the mask. The protection time for light activity in an office room decreases from 7.8 to 1.4 h with surgical mask IIR. The protection time is further reduced by 85 and 99% if the infected person starts to cough or increases the activity level, respectively. Results show the leakage of the mask can considerably affect the performance of the mask. For the surgical mask, the apparent filtration efficiency reduces by 75% with such a leakage, which cannot provide sufficient protection despite the high filtration efficiency of the mask. The facemask model presented provides key input in order to evaluate the protection of masks for different conditions in public places. The physics-based model of the facemask is provided as an online application.

The CAD parametric modeling of RV reducer parts is carried out， and the parametric assembling model of cycloidal gear modification amount and dimension error of parts is established. Based on multi-body dynamics simulation technology， with bearing clearance， dynamics simulation model that includes gear contact and pin-slot contact is established. Considering the small period factors that affect the angular transmission error of RV reducer， the diameter of the needle tooth center circle and the diameter of the needle tooth groove in the same assembly dimension chain are selected to combine the errors， and the dynamics simulation is carried out under rated working conditions，the variation rule of the angular transmission error is analyzed.

Abstract Lithium dendrites cause battery failures and safety hazards in liquid‐electrolyte lithium‐based batteries. To address this problem, each component of the battery, such as cathode, anode, electrolyte and separator, should be well matched and engineered for the integrated battery system. The separator plays an increasingly important role owing to its gradual transformation from an inert to an active component in the battery, especially for resolving Li dendrite issues in Li‐metal batteries. Armed with advanced nanotechnology solutions, separator engineering presents a formidable strategy to suppress dendrite growth dynamics by modifying the electrolyte chemistry, regulating/trapping unwanted ionic species and redirecting dendrite growth direction. This review summarizes recent advances in separator engineering for effective dendrite suppression of Li‐metal anodes. We first introduce the challenges that the Li‐metal anode faces and the irreplaceable role of separators in the battery system. The characterization parameters and design principles of separators are also discussed. Then, the mainstream techniques for separator functionalization and their impacts on dendrite suppression are scrutinized and highlighted. Lastly, the conclusion is drawn and the future outlook for separator engineering is presented.

Abstract Rough Li plating, low ionic conductivity, and low thermal stability of conventional electrolytes post‐primary challenges for achieving reliable high‐capacity rechargeable lithium batteries, for which lithium metal is frequently proposed as the most promising anode material. Conventional low‐polarity commercial polypropylene/polyethylene separators fail to support the application of high‐energy‐density Li anodes due to their rigid physicochemical properties and the high reactivity of Li metal, leading to fatal dendrite formation and vigorous exothermic reaction with electrolytes. Herein, we develop a Li‐wetting, flame‐retardant binary polymer electrolyte by functionalizing poly(vinylidene fluoride) (PVDF) separators with nonflammable polybenzimidazole (PBI) to build safe room‐temperature solid‐state electrolyte membranes. A dendrite‐free LiFePO4 cell with the solid polymer electrolyte (SPE) delivers a discharge capacity of 127 mAh g−1 at 25°C with a capacity retention of 87.5% after 500 cycles at 0.5°C (0.15 mA cm−2). Phase‐field simulations and density functional theory calculations demonstrate that the negatively charged benzimidazole chains of PBI own superior affinity to lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and shares overlapping electron density with Li anode, giving rise to accelerated Li+ conduction at room temperature and uniform Li electrodeposition at the electrolyte/Li metal interface. The SPE is also flame‐retardant since heat‐resistant polytetrafluoroethylene and a dense, heat‐blocking graphitized carbon layer are formed in intense heat through dehydrogenation/fluorination of PVDF under the catalysis of Lewis base imidazole rings and the decomposition of benzimidazole rings in PBI. No such fire‐resistant mechanism is ever reported in conventional electrolytes.

The properties of gun propellants are important for the stability of weapon systems and have been extensively studied in the field of weapon research. In this work, an applied semi-solvent method was used to prepare a triple base gun propellant with nitrated bacterial cellulose (NBC)/nitrocellulose (NC) as the binder system. For the first time, the study found that the addition of NBC in the propellant system resulted in an distinct spatial 3D network structure. The morphology, composition, mechanical properties, energy, thermal behaviour, and combustion performance of the network structure were characterised. The formation mechanism of the spatial network structure and effect of the NBC addition on the propellant performance were discussed. This work verified the application of NBC in different plasticisers and indicated the effective improvement of the impact resistance and burning rate by the spatial network structure propellant with NBC, while retaining other properties.

Abstract Lithium metal batteries (LMBs) have aroused extensive interest in the field of energy storage owing to the ultrahigh anode capacity. However, strong solvation of Li+ and slow interfacial ion transfer associated with conventional electrolytes limit their long‐cycle and high‐rate capabilities. Herein an electrolyte system based on fluoroalkyl ether 2,2,2‐trifluoroethyl‐1,1,2,3,3,3‐hexafluoropropyl ether (THE) and ether electrolytes is designed to effectively upgrade the long‐cycle and high‐rate performances of LMBs. THE owns large adsorption energy with ether‐based solvents, thus reducing Li+ interaction and solvation in ether electrolytes. With THE rich in fluoroalkyl groups adjacent to oxygen atoms, the electrolyte owns ultrahigh polarity, enabling solvation‐free Li+ transfer with a substantially decreased energy barrier and ten times enhancement in Li+ transference at the electrolyte/anode interface. In addition, the uniform adsorption of fluorine‐rich THE on the anode and subsequent LiF formation suppress dendrite formation and stabilize the solid electrolyte interphase layer. With the electrolyte, the lithium metal battery with a LiFePO4 cathode delivers unprecedented cyclic performances with only 0.0012% capacity loss per cycle over 5000 cycles at 10 C. Such enhancement is consistently observed for LMBs with other mainstream electrodes including LiCoO2 and LiNi0.5Mn0.3Co0.2O2, suggesting the generality of the electrolyte design for battery applications.

High-voltage lithium metal batteries (HVLMBs) have been arguably regarded as the most prospective solution to ultrahigh-density energy storage devices beyond the reach of current technologies. Electrolyte, the only component inside the HVLMBs in contact with both aggressive cathode and Li anode, is expected to maintain stable electrode/electrolyte interfaces (EEIs) and facilitate reversible Li+ transference. Unfortunately, traditional electrolytes with narrow electrochemical windows fail to compromise the catalysis of high-voltage cathodes and infamous reactivity of the Li metal anode, which serves as a major contributor to detrimental electrochemical performance fading and thus impedes their practical applications. Developing stable electrolytes is vital for the further development of HVLMBs. However, optimization principles, design strategies, and future perspectives for the electrolytes of the HVLMBs have not been summarized in detail. This review first gives a systematical overview of recent progress in the improvement of traditional electrolytes and the design of novel electrolytes for the HVLMBs. Different strategies of conventional electrolyte modification, including high concentration electrolytes and CEI and SEI formation with additives, are covered. Novel electrolytes including fluorinated, ionic-liquid, sulfone, nitrile, and solid-state electrolytes are also outlined. In addition, theoretical studies and advanced characterization methods based on the electrolytes of the HVLMBs are probed to study the internal mechanism for ultrahigh stability at an extreme potential. It also foresees future research directions and perspectives for further development of electrolytes in the HVLMBs.

Abrscat For the cycloid gear of RV reducer used in robot， on the basis of the isometric modification method， the modification quantity is changed in linear and polynomial ways， and the cycloid tooth profile equations after profile modification are derived. Based on the change rule of pressure angle， by controlling the maximum pressure angle and the maximum profile modification of tooth root and top， the tooth profile modification at different positions in the modification interval of the tooth profile curve can be controlled. The biggest difference between profile modification method based on the pressure angle and the traditional method is that in the working section of cycloid gear， the tooth profile of cycloid gear is standard， and the non-working section and the working section are smoothly connected. The modification program of cycloid tooth profile is compiled in VB， and modification interval and meshing force are compared under different profile modification and pressure angle. Different pressure angles correspond to different working areas， and the meshing force distribution based on pressure angle sectional modification method is more uniform.

The address one of the major challenges facing the lithium metal anode, here the authors use lithiophilic montmorillonite as an additive to the ether-based electrolyte to regulate the lithium ion concentration on the anode surface, facilitating uniform lithium deposition.

Immunogenic cell death (ICD) has been classified as a form of regulated cell death (RCD) that is sufficient to activate an adaptive immune response. Accumulating evidence has demonstrated the ability of ICD to reshape the tumor immune microenvironment through the emission of danger signals or DAMPs, which may contribute to the immunotherapy. Currently, identification of ICD-associated biomarkers that stratify patients according to their benefit from ICD immunotherapy would be of great advantage. Here, we identified two ICD-associated subtypes by consensus clustering. ICD-high subtype was associated with the favorable clinical outcomes, abundant immune cell infiltration, and high activity of immune response signaling. Besides, we established and validated an ICD-related prognostic model that predicted the survival of HNSCC and was associated with tumor immune microenvironment. In conclusion, we established a new classification system of HNSCC based on ICD signatures. This stratification had significant clinical outcomes for estimating prognosis, as well as the immunotherapy of HNSCC patients

This paper presents an experimental study on the tensile behavior of basalt-fiber-grid-reinforced mortar (BGRM) before and after exposure to an elevated temperature of 300 °C considering the effect of fiber grid type, short polyvinyl alcohol fiber (PVA), and high-temperature exposure time. The experimental results show that the mortar plates reinforced with woven textile T25 and fiber-reinforced polymer (FRP) grid G50 exhibited more pronounced strain-hardening behavior. The highest peak stress was obtained for the T25-reinforced plate, which was 85% and 32% higher than that of the T5- and G50-reinforced plates, respectively. Meanwhile, the bridging effect of PVA fibers in mortar can improve the tensile properties. As the high-temperature exposure time increased, the cracking and peak stress of BGRM decreased significantly. Especially for the T5-reinforced plate after exposure to elevated temperature for 2 h, the cracking and peak stress decreased by 60.5% and 38%, respectively. The positive effect of short PVA fibers on the tensile properties of the BGRM became obsolete owing to the melting of short fibers at high temperature. Furthermore, an exponential strength degradation model related to high-temperature exposure time was proposed.

As a new cement-matrix composite material, fiber-reinforced concrete performs excellently in freeze–thaw resistance, tensile resistance, and seepage resistance. Since resistivity can be used to evaluate the performance of concrete, the resistivity of basalt–polypropylene fiber-reinforced concrete (BPFRC) was investigated in this study. Various parameters such as fiber type, fiber content, and water–binder ratio were also analyzed. The resistivity of the BPFRC was tested by an improved two-electrode alternating current (AC) method, and the differences in resistivity were analyzed using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). The results showed that adding fiber affected the resistivity of the BPFRC, and the basalt fiber had a more significant effect than the polypropylene fiber. The resistivity of the BPFRC was sensitive to the water–binder ratio, which showed a negative correlation. In addition, a 365-day resistivity model for the BPFRC was established by considering variables such as fiber, water–binder ratio, ambient temperature, and ambient relative humidity. The hydration equations of various cementitious materials were derived, and a time-varying resistivity model for the BPFRC was developed. Finally, the established resistivity model of the BPFRC lays a foundation for the further building of the relationship between resistivity and BPFRC performance.

The Late Paleozoic is an important epoch of coal-bed accumulation in the North China, particularly in its western segment, where a world-class coal field has been found and exploited for three decades. Coal-bearing layers recorded rapid Late Carboniferous to Early Permian sea-level rise that led to the evolution of the shallow marine tidal flat basin, followed by regression that resulted in the formation of deltaic facies. However, little attention has been paid to the tectonic factors that assisted in the coal accumulation processes, which have been demonstrated worldwide to be pivotal. In this study, we evaluate the significant influence of southward subduction of the middle segment of the Paleo-Asian Ocean (PAO) during Carboniferous to Early Permian deposition of coal-bearing neritic to deltaic successions in the western North China Block (NCB). We pinpoint a direct link between basin-filling evolution of the northwestern Ordos Basin and the progressive uplift of the Inner Mongolia continental arc triggered by the south-dipping subduction of the Solonker ocean plate. Sedimentary facies variation and paleocurrent reconstruction indicate sedimentary routing from the north to northeast. The petrology and detrital zircon geochronology of sampled sandstones indicate evolving provenances from a dominated cratonic basement to a mixed orogen and continental arc. The Carboniferous samples are generally quartz arenites and contain a large number of Archean to Paleoproterozoic zircons with small amounts of Paleozoic arc pluton components, indicating sediment supply dominated by the western NCB Precambrian basement. In contrast, the youngest sample of the Shanxi Formation is sub-litharenite, the age spectrum of which is characterized by the dominance of ca. 450 and 270 Ma ages, indicative of a high influx of Paleozoic arc detritus. This shift in sandstone petrology, detrital zircon distribution, and depositional setting allows us to link the shoaling of the Ordos Basin with mountain building and the unroofing of the continental arc, which enhances our understanding of both the subduction of the PAO and coal accumulation in the NCB.

Graphitic carbon nitride (g-C3N4) fabricated from different precursors exhibits unique microstructures and photocatalytic performance under visible light. Herein, we synthesized five different microstructures of g-C3N4 by the thermal poly condensation method using guanidine hydrochloride, melamine, urea, dicyandiamide and thiourea as the precursors. The results indicated that g-C3N4 prepared from urea precursor (UCN) has a nanostructure, porous layered structure, large specific surface area, and high separation efficiency of photo generated hole-electron pairs, which showed the best photocatalytic activity among all of the as-prepared samples. As for the lowest cost among the above five precursors, urea is an ideal candidate material for preparing g-C3N4 photocatalyst for a huge potential of wide industrial applications. In addition, Pt or Ni were used as the co-catalyst and loaded onto the g-C3N4 surface for photocatalytic hydrogen production. In comparison with noble metal Pt co-catalyst, Ni co-catalyst is inexpensive and has a significant effect o enhancing the photocatalytic activity under visible light. Therefore, Ni exhibits a considerable prospect to replace noble metal co-catalysts in the photocatalytic reactions.

Industrial wastewater contains diverse toxic dyes and drugs, which pollute the environment and poison creatures. Utilizing photocatalysts has been accepted to be an effective method to degrade water pollutions using solar light. Crystalline bismuth ferrite (Bi2Fe4O9) with a band gap of 1.9–2.0 eV is expected to be one of the most promising candidates for photocatalysts in the visible light region. Amorphous graphene is also a promising candidate as a photocatalyst owing to its excellent electronic and optical properties. Herein, a composite of Bi2Fe4O9/graphene aerogels (GAs) was prepared with a two-step hydrothermal method. The prepared Bi2Fe4O9 powders were confirmed to be successfully doped into GAs and evenly dispersed between graphene sheets. The Bi2Fe4O9/GA composite was utilized to perform photodegradation for organic dyes and antibiotic drugs under visible light irradiation, yielding efficiencies of 90.22%, 92.3%, 71.8% and 78.58% within 330 min for methyl orange, methylene blue, Rhodamine B and tetracycline hydrochloride, respectively. Such distinct photocatalytic activities overwhelmed the pure Bi2Fe4O9 powders of 14.10%, 22.19%, 13.98% and 48.08%, respectively. Additionally, the composite produced a degradation rate constant of 0.00623 min−1 for methylene blue, which is significantly faster than that of 0.00073 min−1 obtained by the pure powder. These results provide an innovative strategy for designing 3D visible-light-responsive photocatalysts combined with graphene aerogel for water purification.

Potassium chloride crystals are good conductors in the UV to mid-infrared broadband and can be widely used as materials for high-power CO2 lasers. However, the most important use of potassium chloride crystals has been overlooked; their stable chemistry and wide electrochemical window allow them to form molten eutectic salts with other chlorides for the dry reprocessing of spent fuel. The aim of this work is to investigate the electrochemical properties of the actinide substitute cerium metal on liquid indium media in order to provide basic data for further realization of lanthanides (Ln)/actinides (An) separation. In this paper, we investigated the electrochemical behavior of 3LiCl-2KCl-CeCl3 melt at liquid metal media indium (In) electrode using various transient electrochemical analysis methods, such as cyclic voltammetry, square wave voltammetry and open circuit potential technique. The quasi-equilibrium potentials of Ce3+ at different temperatures on the liquid metal In electrode were determined. On the redox process, the reaction kinetics of the oxidation–reduction process in the 3LiCl-2KCl-CeCl3 system is studied. It was determined that the reduction of Ce3+ at the liquid metal In electrode is an irreversible single-step process with three electron transfers. The relationship between the diffusion coefficient and the reduction process of Ce3+ ions on liquid metal indium electrodes at different temperatures was determined. The expression for the diffusion coefficient and temperature of Ce3+ at the liquid metal indium electrode is: lnD = 1.43 − 7974.69/T.

Abstract In the current COVID‐19 pandemic, wearing masks and hand disinfection are widely adopted hygiene practices. Alcohol‐based sanitizers are commonly used for hand disinfection, however, the alcohol vapors can dissipate the charges on electrostatic filters. In the present study, the effects of alcohol vapors from alcohol‐based sanitizers during hand disinfection on the in‐use masks are studied. The results show that the negative effects are not significant for nonelectrostatic cotton masks or N95 respirators with multiple charged layers, but noticeable for surgical masks. After five rounds of hand disinfection, the filtration efficiencies of the filtering materials of the surgical masks decrease by more than 8% for 400 and 500 nm particles and by 3.7 ± 1.8% for 1 µm particles, the effective filtration efficiency of the surgical masks worn by the volunteers (with leakage considered) decreases by about 5% for ambient aerosol. In another process to imitate intensive disinfection procedures by healthcare workers, a 30 min surface cleaning process using alcohol‐based sanitizer is performed, and the effective efficiency of the N95 respirators worn by the volunteers decreases by nearly 9%. The simple practice of avoiding vapor during hand disinfection could mitigate the effects of alcohol vapor, which is demonstrated on two brands of surgical masks.

With the further acceleration in the industrialization process, organic pollutants and gas pollution in the environment have posed severe threats to human health. It has been a global challenge regarding achieving an efficient solution to pollutant degradation. In such a context, photocatalysts have attracted researchers’ attention for their simplicity, efficiency, cleanliness and low cost. However, the single photocatalyst is facing a research bottleneck owing to its narrow light absorption spectrum and high photocarrier recombination rate. Given that heterojunctions can achieve efficient separation of photogenerated carriers in space, constructing heterostructured photocatalysts has become the most perspective method to improve the performance of photocatalysts. Furthermore, nanoparticles prepared through colloidal chemistry have the characteristics of high dispersion, stability and adsorption, further enhancing the degradation efficiency of heterostructured photocatalysts. This article reviews the primary methods for preparing heterostructured photocatalysts through colloidal chemistry, classifies the heterojunction types by transport routes of photogenerated carriers and summarizes the recent progress of heterostructured photocatalysts in pollutant degradation. To implement environmental remediation, it is crucial to explore economical and efficient photocatalysts for practical applications. It is hoped that this review will stimulate further exploration of colloidal heterostructured photocatalysts for pollutant degradation.

Summary: Although Li-metal anodes are extremely attractive owing to the ultrahigh theoretical specific capacity, the low Coulombic efficiency and severe safety hazards resulting from uncontrollable Li dendrites growth hinder their widespread implementation. Herein, we propose a novel design of Ni macropore arrays for the functional Li deposition host. Benefiting from the regulated electric field distribution, Li nucleation and growth can be well confined within conductive Ni macropores. Consequently, the Ni macropore array electrode exhibits stable Li deposition behavior, i.e., high Coulombic efficiency of above 97% over 400 cycles for 1.0 mAh cm−2. Most importantly, the LiFePO4 || Li-Ni macropore arrays full cell also shows greatly enhanced cycling stability (90.3 mAh g−1 at 1 C after 700 cycles), holding great promise for high-performance rechargeable Li metal batteries.

To solve the problem of the effective cushioning of fast-moving mechanical components in small ring-shaped spaces, the factors affecting the compression and energy absorption properties of small-sized hollow metal tubes were studied. Simulation models were constructed to analyse the influences of tube diameter, wall thickness, relative position, and number of stacked components on the compression and energy absorption properties. The correctness of the simulation method and its output were verified by experiments, which proved the effectiveness of compression and energy absorption properties of small-sized thin-walled metal tubes. The research provides support for the application of metal tube buffers in armament launch technology and engineering practice.

Saponins are natural compounds and possess the most promising anti-cancer function. Here, a saponin gleditsia saponin C (GSC), extracted from gleditsiae fructus abnormalis, could induce apoptosis of lung tumor cell line A549 via caspase dependent cascade and this effect could be prevented by the caspase inhibitors. In addition, GSC induced cell death companied with an increase ratio of Bax:Bcl-2 and inhibition of ERK and Akt signaling pathways. Meanwhile, GSC suppressed TNFα inducing NF-κB activation and increased the susceptibility of lung cancer cell to TNFα induced apoptosis. Furthermore, on mouse xenograft model, GSC significantly suppressed tumor growth and induced cancer cell apoptosis, which validated the anti-tumor effect of GSC. Based on these results, GSC might be a promising drug candidate of anti-lung cancer for its potential clinical applications.

In this work, a thermal degradation mechanism of room temperature vulcanized (RTV) phenyl silicone rubber that was vulcanized by different crosslinking agents was discussed. Firstly, RTV phenyl silicone rubber samples were prepared by curing hydroxyl-terminated polymethyldiphenylsiloxane via three crosslinking agents, namely, tetraethoxysilane (TEOS), tetrapropoxysilane (TPOS), and polysilazane. Secondly, the ablation properties of RTV phenyl silicone rubber were studied by the muffle roaster test and FT-IR. Thirdly, thermal stability of the three samples was studied by thermogravimetric (TG) analysis. Finally, to explore the thermal degradation mechanism, the RTV phenyl silicone rubber vulcanized by different crosslinking agents were characterized by TG analysis-mass spectrum (TG-MS) and pyrolysis gas chromatogram-mass spectrum (pyGC-MS). Results showed that the thermal stability of RTV phenyl silicone rubber is related to the amount of residual Si–OH groups. The residual Si–OH groups initiated the polysiloxane chain degradation via an ‘unzipping’ mechanism.

In recent years, the research on supercapacitors has ushered in an explosive growth, which mainly focuses on seeking nano-/micro-materials with high energy and power densities. Herein, this review will be arranged from three aspects. We will summarize the controllable architectures of spinel NiCo2O4 fabricated by various approaches. Then, we introduce their performances as supercapacitors due to their excellent electrochemical performance, including superior electronic conductivity and electrochemical activity, together with the low cost and environmental friendliness. Finally, the review will be concluded with the perspectives on the future development of spinel NiCo2O4 utilized as the supercapacitor electrodes.