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A flame-retardant binder with high polysulfide affinity for safe and stable lithium–sulfur batteries

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Science China Chemistry 2024年第3期67卷 1028-1036页

作者： Guowei Yu Guofeng Ye Cheng wang Chenyang wang Zhaoyun wang Pu Hu Yu li Xi-Xi Feng Shuang-Jie Tan min Yan Sen Xin Zhitian liu Hubei Key Laboratory of Plasma Chemistry and Advanced Materials Hubei Engineering Technology Research Center of Optoelectronic and New Energy MaterialsSchool of Materials Science and EngineeringWuhan Institute of TechnologyWuhan 430205China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecular SciencesBeijing National Laboratory for Molecular Sciences(BNLMS)Institute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China University of Chinese Academy of Sciences Beijing 100049China

lithium-sulfur(li-S) batteries have shown promises for the next-generation, high-energy electrochemical storage, yet are hindered by rapid performance decay due to the polysulfide shuttle in the cathode and safety concerns about potential thermal runaway. To address the above challenges, herein, we show a flame-retardant cathode binder that simultaneously improves the electrochemical stability and safety of batteries. The combination of soft and hard segments in the polymer framework of binders allows high flexibility and mechanical strength for adapting to the drastic volume change during the li(de)intercalation of the S cathode. The binder contains a large number of polar groups, which show the high affinity to polysulfides so that they help to anchor active S species at the cathode. These polar groups also help to regulate and facilitate the li-ion transport, promoting the kinetics of polysulfide conversion reaction. The binder contains abundant phosphine oxide groups, which, in the case of battery's thermal runaway, decompose and release PO· radicals to quench the combustion reactions and stop the fire. Consequently, li-S batteries using the new cathode binder show the improved electrochemical performance, including a low-capacity decay of 0.046% per cycle for 800 cycles at 1 C and favorable rate capabilities of up to 3 C. This work offers new insights on the practical realization of high-energy rechargeable batteries with stable storage electrochemistry and high safety.

关键词： lithium–sulfur battery polymer binder polysulfide affinity flame retardancy

Influences of Co-Flow and Counter-Flow Modes of Reactant Flow Arrangement on a PEMFC at Start-Up

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1337-1356页

作者： Qianqian Shao min wang Nuo Xu School of Petroleum Engineering Guangdong University of Petrochemical TechnologyMaoming525000China Mechanics Division Beijing Computational Science Research CenterBeijing100193China

To investigate the influences of co-flowand counter-flowmodes of reactant flowarrangement on a proton exchange membrane fuel cell(PEMFC)during start-up,unsteady physical and mathematical models fully coupling the flow,heat,and electrochemical reactions in a PEMFC are established.The continuity equation and momentum equation are solved by handling pressure-velocity coupling using the SIMPLE algorithm.The electrochemical reaction rates in the catalyst layers(CLs)of the cathode and anode are calculated using the Butler-Volmer equation.The multiphase mixture model describes the multiphase transport process of gas mixtures and liquid water in the fuel cell.After validation,the influences of co-flow and counter-flow modes on the PEMFC performance are investigated,including the evolution of the current density,flow field,temperature field,and reactant concentration field during start-up,as well as the steady distribution of the current density,reactant concentration,andmembrane water content when the start-up stabilizes.Co-flow and counter-flow modes influence the current density distribution and temperature distribution.On the one hand,the co-flow mode accelerates the start-up process of the PEMFC and leads to a more evenly distributed current density than the counter-flow mode.On the other hand,the temperature difference between the inlet and outlet sections of the cell is up to 10.1℃ under the co-flow mode,much larger than the 5.0℃ observed in the counter-flow mode.Accordingly,the counter-flowmode results in a more evenly distributed temperature and a lower maximum temperature than the co-flow case.Therefore,in the flow field design of a PEMFC,the reactant flow arrangements can be considered to weigh between better heat management and higher current density distribution of the cell.

关键词： PEMFC full coupling model Butler-Volmer equation multiphase mixture model co-flow mode counter-flow mode

Treatment of lacrimal gland adenoid cystic carcinoma:a systematic review and Meta-analysis

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 164-172页

作者： Hai-Han Yan Rui liu Nan wang liang-Yuan Xu Qi-Han Guo Jing li Jian-min Ma Beijing Institute of Ophthalmology Beijing Tongren Eye CenterBeijing Tongren HospitalCapital Medical UniversityBeijing Ophthalmology&Visual Sciences Key LaboratoryBeijing 100730China

AIM:To evaluate lacrimal gland adenoid cystic carcinoma(LGACC)of prognosis in patients who underwent different treatment regimens.METHODS:We searched PubMed,EMBASE,and the Cochrane library for studies done on the treatment of LGACC,between January 1987 and April 2022.A Metaanalysis was conducted to pool the 5-year overall survival rate(OR),and the 5-year recurrence rate(RR)and 5-year metastasis rate(MR)were assessed.RESULTS:The 30 studies involved 585 patients were included in the Meta-analysis.The pooled 5-year OR with surgery alone was 50%,the 5-year RR was 63%,and the 5-year MR was 34%.The pooled 5-year OR with surgery and adjuvant radiotherapy combined was 67%(95%CI 61%,73%),the 5-year RR was 41%,and the 5-year MR was 35%.The pooled 5-year OR with surgery and adjuvant chemoradiotherapy combined was 72%(95%CI 59%,84%),the 5-year RR was 48%,and the 5-year MR was 36%.The pooled 5-year OR with surgery,intra-arterial cytoreductive chemotherapy,and adjuvant chemoradiotherapy combined was 78%(95%CI 68%,89%),the 5-year RR was 15%,and the 5-year MR was 27%.CONCLUSION:Comprehensive treatment is more effective than surgery alone.Surgery combined with intraarterial chemotherapy and adjuvant chemoradiotherapy seems to add value to the therapeutic effect of comprehensive treatment of LGACC but further high-quality research is required to validate this.

关键词： adenoid cystic carcinoma lacrimal gland Meta-analysis

The significance of long non-coding RNAs in the pathogenesis,diagnosis and treatment of inflammatory bowel disease

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Precision Clinical Medicine 2024年第1期7卷 34-53页

作者： Fei Jiang min Wu Rongpeng li Jiangsu Province Engineering Research Center of Cardiovascular Drugs Targeting Endothelial Cells School of Life SciencesJiangsu Normal UniversityXuzhou 221000China Department of Laboratory Medicine the Affliated Hospital of Xuzhou Medical UniversityXuzhou 221000China Drug Discovery Section Wenzhou InstituteUniversity of Chinese Academy of SciencesWenzhou 325000China Department of Neurology Medical College of WisconsinMilwaukeeWI 53226USA

Inflammatory bowel diseases(IBD)are a group of chronic relapsing gastrointestinal inflammatory diseases with significant global incidence.Although the pathomechanism of IBD has been extensively investigated,several aspects of its pathogenesis remain unclear.Long non-coding RNAs(lncRNAs)are transcripts with more than 200 nucleotides in length that have potential protein-coding functions.LncRNAs play important roles in biological processes such as epigenetic modification,transcriptional regulation and posttranscriptional regulation.In this review,we summarize recent advances in research on IBD-related lncRNAs from the perspective of the overall intestinal microenvironment,as well as their potential roles as immune regulators,diagnostic biomarkers and therapeutic targets or agents for IBD.

关键词： IncRNAs inflammatory bowel diseases intestinal barrier intestinal microenvironment immune regulator diagnostic biomarker therapeutic target

A multi-source information fusion layer counting method for penetration fuze based on TCN-LSTM

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Defence Technology（防务技术） 2024年第3期33卷 463-474页

作者： Yili wang Changsheng li Xiaofeng wang Nanjing University of Science and Technology Nanjing 210094JiangsuChina State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

When employing penetration ammunition to strike multi-story buildings,the detection methods using acceleration sensors suffer from signal aliasing,while magnetic detection methods are susceptible to interference from ferromagnetic materials,thereby posing challenges in accurately determining the number of layers.To address this issue,this research proposes a layer counting method for penetration fuze that incorporates multi-source information fusion,utilizing both the temporal convolutional network(TCN)and the long short-term memory(LSTM)recurrent network.By leveraging the strengths of these two network structures,the method extracts temporal and high-dimensional features from the multi-source physical field during the penetration process,establishing a relationship between the multi-source physical field and the distance between the fuze and the target plate.A simulation model is developed to simulate the overload and magnetic field of a projectile penetrating multiple layers of target plates,capturing the multi-source physical field signals and their patterns during the penetration process.The analysis reveals that the proposed multi-source fusion layer counting method reduces errors by 60% and 50% compared to single overload layer counting and single magnetic anomaly signal layer counting,respectively.The model's predictive performance is evaluated under various operating conditions,including different ratios of added noise to random sample positions,penetration speeds,and spacing between target plates.The maximum errors in fuze penetration time predicted by the three modes are 0.08 ms,0.12 ms,and 0.16 ms,respectively,confirming the robustness of the proposed model.Moreover,the model's predictions indicate that the fitting degree for large interlayer spacings is superior to that for small interlayer spacings due to the influence of stress waves.

关键词： Penetration fuze Temporal convolutional network(TCN) Long short-term memory(LSTM) Layer counting Multi-source fusion

FlowGANAnomaly: Flow-Based Anomaly Network Intrusion Detection with Adversarial Learning

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Chinese Journal of Electronics 2024年第1期33卷 58-71页

作者： Zeyi li Pan wang Zixuan wang School of Computer Science Nanjing University of Posts and Telecommunications School of Modern Posts Nanjing University of Posts and Telecommunications School of Internet of Things Nanjing University of Posts and Telecommunications

In recent years, low recall rates and high dependencies on data labelling have become the biggest obstacle to developing deep anomaly detection(DAD) techniques. Inspired by the success of generative adversarial networks(GANs) in detecting anomalies in computer vision and imaging, we propose an anomaly detection model called Flow GANAnomaly for detecting anomalous traffic in network intrusion detection systems(NIDS). Unlike traditional GAN-based approaches, which are composed of a flow encoder, a convolutional encoder-decoder-encoder, a flow decoder and a convolutional encoder, the architecture of this model consists of a generator(G) and a discriminator(D).Flow GANAnomaly maps the different types of traffic feature data from separate datasets to a uniform feature space,thus can capture the normality of network traffic data more accurately in an adversarial manner to mitigate the problem of the high dependence on data labeling. Moreover, instead of simply detecting the anomalies by the output of D, we proposed a new anomaly scoring method that integrates the deviation between the output of two Gs’ convolutional encoders with the output of D as weighted scores to improve the low recall rate of anomaly detection. We conducted several experiments comparing existing machine learning algorithms and existing deep learning methods(Auto Encoder and VAE) on four public datasets(NSL-KDD, CIC-IDS2017, CIC-DDo S2019, and UNSW-NB15). The evaluation results show that Flow GANAnomaly can significantly improve the performance of anomaly-based NIDS.

关键词： Anomaly detection Unsupervised learning Generative adversarial network Intrusion detection system

Al/Hf ratio-dependent mechanisms of microstructure and mechanical property of nearly fully dense Al—Hf reactive material

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Defence Technology（防务技术） 2024年第1期31卷 230-241页

作者： Junbao li Weibing li Xiaoming wang ZNDY of ministerial Key Laboratory Nanjing University of Science and TechnologyNanjing 210094China

This study proposed three types of Al—Hf reactive materials with particle size ratios(a),which were almost completely dense(porosity of<5.40%)owing to their preparation using hot-pressing technology.Microstructure ch... 详细信息

This study proposed three types of Al—Hf reactive materials with particle size ratios(a),which were almost completely dense(porosity oflinearly with increasing strain rate.ε.It is found that the plastic deformation of the material increased with increasing strain rate.As a increased from 0.1 to 1,the flow stress gradually increased.Impact failure of the material was dominated by ductile fracture with a large Al phase plastic deformation band for lower a,while brittle fracture with crushed Hf particles occurred at higher a.Finally,a constitutive model based on BP neural network was proposed to describe the stress-strain relationships of the materials,with an average relative error of 2.22%.

关键词： Reactive material Particle size Split Hopkinson pressure bar test Stressestrain relationship Impact failure BP neural network

Probing the Kinematic Signatures of Planet Formation in the Gas Disk of MWC 480

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Research in Astronomy and Astrophysics 2024年第6期24卷 112-120页

作者： min Zhao Haochuan Yu Zhengxiang li Department of Astronomy Beijing Normal University Sub-department of Astrophysics Department of Physics University of Oxford

The disk around MWC 480 has shown multiple substructures in both dust and gas observations, possibly suggesting ongoing planet formation in situ. In this paper, we explore the gas kinematics of the MWC 480 disk by analyzing the archival Atacama Large Millimeter/submillimeter Array observations of12CO（J = 2-1）,13CO（J = 2-1）, and C18O（J = 2-1）. By modeling the line-of-sight velocities, inferred from the Doppler shifts of the emission lines, we are able to decompose the three-dimensional（3D） velocity field of the disk into rotational,radial, and vertical components. Further analysis reveals the presence of large-scale gas flows in the（r, z） plane.Notably, we identify potential meridional flows across various heights as traced by all three CO isotopologues in the 80–120 au region, possibly associated with ongoing planet formation activities in this region. Moreover, we find upward flows near 200 au for all three CO isotopologues, which may point to the presence of disk winds.

关键词： planet-disk interactions planet-star interactions protoplanetary disks

Adaptive and augmented active anomaly detection on dynamic network traffic streams

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Frontiers of Information Technology & Electronic Engineering 2024年第3期25卷 446-460页

作者： Bin li Yijie wang li CHENG National Key Laboratory of Parallel and Distributed Computing College of ComputerNational University of Defense TechnologyChangsha 410073China College of System Engineering National University of Defense TechnologyChangsha 410073China

Active anomaly detection queries labels of sampled instances and uses them to incrementally update the detection model,and has been widely adopted in detecting network attacks.However,existing methods cannot achieve desirable performance on dynamic network traffic streams because(1)their query strategies cannot sample informative instances to make the detection model adapt to the evolving stream and(2)their model updating relies on limited query instances only and fails to leverage the enormous unlabeled instances on streams.To address these issues,we propose an active tree based model,adaptive and augmented active prior-knowledge forest(A3PF),for anomaly detection on network trafic streams.A prior-knowledge forest is constructed using prior knowledge of network attacks to find feature subspaces that better distinguish network anomalies from normal traffic.On one hand,to make the model adapt to the evolving stream,a novel adaptive query strategy is designed to sample informative instances from two aspects:the changes in dynamic data distribution and the uncertainty of anomalies.On the other hand,based on the similarity of instances in the neighborhood,we devise an augmented update method to generate pseudo labels for the unlabeled neighbors of query instances,which enables usage of the enormous unlabeled instances during model updating.Extensive experiments on two benchmarks,CIC-IDS2017 and UNSW-NB15,demonstrate that A3PF achieves significant improvements over previous active methods in terms of the area under the receiver operating characteristic curve(AUC-ROC)(20.9%and 21.5%)and the area under the precision-recall curve(AUC-PR)(44.6%and 64.1%).

关键词： Active anomaly detection Network traffic streams Pseudo labels Prior knowledge of network attacks