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Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates

Defence Technology（防务技术） 2024年第7期37卷 96-110页

作者： Xing chen Yonggang lu Zhiwen Li Zhonghua Cui Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina Chongqing Qianwei Technology Group Co. LtdChongqing 401121China

In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were *** diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 *** spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement *** test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the ***,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually *** line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody *** will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will *** radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by *** findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characte

关键词： Hypervelocity impact Flash radiation Evolution Spectral characteristics Damage evaluation

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Metarelation2vec:A Metapath-Free Scalable Representation Learning Model for Heterogeneous Networks

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Tsinghua Science and Technology 2024年第2期29卷 553-575页

作者： Lei chen yuan Li Yong Lei Xingye Deng School of Information and Electrical Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Computer Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

Metapaths with specific complex semantics are critical to learning diverse semantic and structural information of heterogeneous networks(HNs)for most of the existing representation learning ***,any metapaths consisting of multiple,simple metarelations must be driven by domain *** sensitive,expensive,and limited metapaths severely reduce the flexibility and scalability of the existing models.A metapath-free,scalable representation learning model,called Metarelation2vec,is proposed for HNs with biased joint learning of all metarelations in a bid to address this ***,a metarelation-aware,biased walk strategy is first designed to obtain better training samples by using autogenerating cooperation probabilities for all metarelations rather than using expert-given ***,grouped nodes by the type,a common and shallow skip-gram model is used to separately learn structural proximity for each node ***,grouped links by the type,a novel and shallow model is used to separately learn the semantic proximity for each link ***,supervised by the cooperation probabilities of all meta-words,the biased training samples are thrown into the shallow models to jointly learn the structural and semantic information in the HNs,ensuring the accuracy and scalability of the *** experimental results on three tasks and four open datasets demonstrate the advantages of our proposed model.

关键词： metarelation random walk heterogeneous network metapath representation learning

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Metal-Free Photocatalytic[4+2]Annulation of Acrylamides with 2-Benzyl-2-bromocarbonyls to Assemble Tetralin-1-carboxamides

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Chinese Journal of Chemistry 2024年第2期42卷 157-163页

作者： Weicai Li lu Tan Yijun chen Rui Liu Zhongyu Qi Shixuan yuan Zhanwen Huang Siping Wei Xi Du Dong Yi Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province School of PharmacySouthwest Medical UniversityLuzhouSichuan 646000China Department of Chemistry School of Basic Medical ScienceSouthwest Medical UniversityLuzhouSichuan 646000China Department of Pharmacy Affiliated HospitalSouthwest Medical UniversityLuzhouSichuan 646000China

Tetralin-1-carboxamides are frequently incorporated in myriad medicinally important ***,their existing synthetic routes not only suffer from some drawbacks such as tedious procedures,harsh reaction conditions,narrow substrate scope,low yields,and environmental problems,but are also based upon the elaboration of uneasily available non-linear tetralin ***,we describe a metal-and additive-free visible light-induced[4+2]annulation of two simple linear starting materials,namely acrylamides and 2-benzyl-2-bromocarbonyls,through a cascade C(sp^(3))-Br/C(sp^(2))-H bond cleavage,double C-C bond formation,and aromatization *** developed protocol provides a convenient,efficient,and green approach to a variety of tetralin-1-carboxamide derivatives with good functional group ***,the resulting products could also undergo the Licl-mediated mono-decarboxylative cyclization process to further furnish the architecturally novel bridged polycyclic imides with excellentcis-diastereoselectivities.

关键词： Annulation Metal-free Photoredox catalysis Tetralin-1-carboxamide Cyclic imides Synthetic methods C-C coupling Radical reactions Reaction mechanisms

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Crowdsourcing RTK:a new GNSS positioning framework for building spatial high-resolution atmospheric maps based on massive vehicle GNSS data

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Satellite Navigation 2024年第1期5卷 91-108页

作者： Hongjin Xu Xingyu chen Jikun Ou Yunbin yuan State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and Technology(APM)Chinese Academy of Sciences(CAS)Wuhan430071China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina

High-quality spatial atmospheric delay correction information is essential for achieving fast integer ambiguity resolution(AR)in precise ***,traditional real-time precise positioning frameworks(i.e.,NRTK and PPP-RTK)depend on spatial low-resolution atmospheric delay correction through the expensive and sparsely distributed CORS *** results in limited public *** the mass production of autonomous driving vehicles,more cost-effective and widespread data sources can be explored to create spatial high-resolution atmospheric *** this study,we propose a new GNSS positioning framework that relies on dual base stations,massive vehicle GNSS data,and crowdsourced atmospheric delay correction maps(CAM).The map is easily produced and updated by vehicles equipped with GNSS receivers in a crowd-sourced ***,the map consists of between-station single-differenced ionospheric and tropospheric *** introduce the whole framework of CAM initialization for individual vehicles,on-cloud CAM maintenance,and CAM-augmented user-end *** map data are collected and preprocessed in ***,the crowdsourced data are uploaded to a cloud *** massive data from multiple vehicles are merged in the cloud to update the CAM in ***,the CAM will augment the user positioning *** framework forms a beneficial cycle where the CAM’s spatial resolution and the user positioning performance mutually improve each *** validate the performance of the proposed framework in real-world experiments and the applied potency at different spatial *** highlight that this framework is a reliable and practical positioning solution that meets the requirements of ubiquitous high-precision positioning.

关键词： New GNSS positioning framework Spatial high-resolution atmospheric delay correction Crowdsourced atmospheric delay correction maps Crowdsourced ionosphere Crowdsourced troposphere Ubiquitous

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Biomaterials and tissue engineering in traumatic brain injury:novel perspectives on promoting neural regeneration

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Neural Regeneration Research 2024年第10期19卷 2157-2174页

作者： Shihong Zhu Xiaoyin Liu Xiyue lu Qiang Liao Huiyang luo yuan Tian Xu cheng Yaxin Jiang Guangdi Liu Jing chen Department of Neurosurgery West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina National Engineering Research Center for Biomaterials College of Biomedical EngineeringSichuan UniversityChengduSichuan ProvinceChina Department of Anesthesiology West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Department of Pharmacy West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Out-patient Department West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina Department of Respiratory and Critical Care Medicine West China HospitalWest China Medical SchoolSichuan UniversityChengduSichuan ProvinceChina

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties

关键词： bioactive materials biomaterials exosomes neural regeneration scaffolds stem cells tissue engineering traumatic brain injury

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Inelastic Scattering of Dark Matter with Heavy Cosmic Rays

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Research in Astronomy and Astrophysics 2024年第6期24卷 68-80页

作者： Keyu lu Yue-Lin Sming Tsai Qiang yuan Le Zhang School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area SYSUZhuhai 519082China Peng cheng Laboratory Shenzhen 518000China

We investigate the impact of inelastic collisions between dark matter(DM)and heavy cosmic ray(CR)nuclei on CR *** approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections,allowing us to assess how these collisions affect the spectra of CR boron and *** derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary *** a specific example with a coupling strength of b_(χ)=0.1 and a DM mass of m_(χ)=0.1 GeV,considering a simplified scenario where DM interacts exclusively with oxygen,a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is ***,the peak within the spectrum,spanning from 0.1 to 10 GeV,experiences an enhancement of approximately 1.5 ***,in a more realistic scenario where DM particles interact with all CRs,this peak can be amplified to twice its original *** the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio,we estimate a 95%upper limit for the effective inelastic cross-section of DM-proton as a function of DM *** findings reveal that at m_(χ)?2 MeV,the effective inelastic cross-section between DM and protons must be less than O(10^(-32))cm^(2).

关键词： elementary particles nuclear reactions nucleosynthesis abundances scattering astroparticle physics (cosmology:)dark matter

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Distributed active vibration control for helicopter based on diffusion collaboration

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Chinese Journal of Aeronautics 2024年第8期37卷 208-232页

作者： Yang yuan Yang lu Xunjun MA Jingliang LI Huiyu YUE National Key Laboratory of Helicopter Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Wuhan Second Ship Design and Research Institute Wuhan 430205China

The active vibration control technology has been successfully applied to several helicopter ***,with the increasing of control scale,traditional centralized control algorithms are experiencing significant increase of computational complexity and physical implementation *** address this issue,a diffusion collaboration-based distributed Filtered-x Least Mean Square algorithm applied to active vibration control is proposed,drawing inspiration from the concept of data fusion in wireless sensor *** algorithm distributes the computation load to each node,and constructs the active vibration control network topology of large-scale system by discarding the weak coupling secondary paths between nodes,achieving distributed active vibration *** order to thoroughly validate the effectiveness and superiority of this algorithm,a helicopter fuselage model is designed as the research ***,the excellent vibration reduction performance of the proposed algorithm is confirmed through ***,specialized node control units are developed,which utilize STM32 microcontroller as the processing ***,a distributed control system is constructed based on multi-processor *** on this foundation,a large-scale active vibration control experimental platform is *** on the platform,experiments are carried out,involving the 4-input 4-output system and the 8-input 8-output *** experimental results demonstrate that under steady-state harmonic excitation,the proposed algorithm not only ensures control effectiveness but also reduces computational complexity by 50%,exhibiting faster convergence speed compared with traditional centralized *** time-varying external excitation,the proposed algorithm demonstrates rapid tracking of vibration changes,with vibration amplitudes at all controlled points declining by over 94%,proving the strong robustness and adaptive capability of the algorithm

关键词： Helicopter Active vibration control Diffusion collaboration Distributed control Experiment

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Ultralow charge-discharge voltage gap of 0.05 V in sunlight-responsive neutral aqueous Zn-air battery

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Carbon Energy 2024年第9期6卷 172-183页

作者： Zhimin Niu Yan Gao Tianhui Wu Fei Zhang Ran Zhao Zijia chen Yiming yuan Tifeng Jiao Jianmin Gu Li lu Desong Wang State Key Laboratory of Metastable Materials Science and Technology(MMST) Hebei Key Laboratory of Applied ChemistryYanshan UniversityQinhuangdaoChina Department of Mechanical Engineering National University of SingaporeSingaporeSingapore School of Sciences Hebei University of Science and TechnologyShijiazhuangChina

Rechargeable neutral aqueous zinc-air batteries(ZABs)are a promising type of energy storage device with longer operating life and less corrosiveness compared with conventional alkaline ***,the neutral ZABs normally possess poor oxygen evolution reactions(OERs)and oxygen reduction reactions performance,resulting in a large charge–discharge voltage gap and low round-trip ***,we demonstrate a sunlight-assisted strategy for achieving an ultralow voltage gap of 0.05 V in neutral ZABs by using the FeOOH-decorated BiVO4(Fe-BiVO4)as an oxygen *** sunlight,the electrons move from the valence band(VB)of Fe-BiVO_(4) to the conduction band producing holes in VB to promote the OER process and hence reduce the ***,the photopotential generated by the Fe-BiVO_(4) compensates a part of the charging potential of neutral ***,the energy loss of the battery could be compensated via solar energy,leading to a record-low gap of 0.05 V between the charge and discharge voltage with a high round-trip efficiency of 94%.This work offers a simple but efficient pathway for solar-energy utilization in storage devices,further guiding the design of high energy efficiency of neutral aqueous ZABs.

关键词： neutral ZABs oxygen catalytic reactions photocatalysis round-trip efficiency solar energy

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Antecedent snowmelt and orographic precipitation contributions to water supply of Pakistan disastrous floods,2022

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Advances in Climate Change Research 2024年第3期15卷 419-430页

作者： Yan WANG Peng CUI chen-Di ZHANG Guo-Tao ZHANG Jian-Sheng HAO Xu yuan Yao-Zhi JIANG lu WANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Mountain Hazards and Earth Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Polar and Marine Research Institute College of Harbor and Coastal EngineeringJimei UniversityXiamen 361021China School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu 610054China Hebei Province Tangshan Caofeidian Meteorological Bureau Tangshan 063000China

In 2022,the Pakistan witnessed the hottest spring and wettest summer in *** devastating floods inundated a large portion of Pakistan and caused enormous ***,the primary water source and its contributions to these unprecedented floods remain *** on the reservoir inflow measurements,Multi-Source Weighted-Ensemble Precipitation(MSWEP),the fifth generation ECMWF atmospheric reanalysis(ERA5)products,this study quantified the contributions of monsoon precipitation,antecedent snow-melts,and orographic precipitation enhancement to floods in *** found that the Indus experienced at least four inflow up-rushes,which was mainly supplied by precipitation and snowmelt;In upper Indus,abnormally high temperature continued to influence the whole summer and lead to large amounts of snowmelts which not only was a key water supply to the flood but also provided favorable soil moisture conditions for the latter *** July,the snowmelt has higher contributions than the precipitation to the streamflow of Indus River,with contribution value of more than 60%.Moreover,the snowmelt could still supply 20%-40%water to the lower Indus in July and August;The leading driver of 2022 mega-floods over the southern Pakistan in July and August was dominated by the precipitation,where terrain disturbance induced precipitation account to approximately 33%over the southern *** results help to understand the mechanisms of flood formation,and to better predict future flood risks over complex terrain regions.

关键词： Extreme heavy rainfall Snowmelt Orographic precipitation Floods Pakistan

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Surface engineering of Li-and Mn-rich layered oxides for superior Li-ion battery

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Tungsten 2024年第1期6卷 259-268页

作者： lu-Xiang Ma Tian-Dong chen Chun-Xi Hai Sheng-De Dong Xin He Qi Xu Hang Feng AXin Ji-Tao chen yuan Zhou College of Materials and Chemistry and Chemical Engineering Chengdu University of TechnologyChendu 610000China Qinghai Building and Materials Research Co. LtdXining 810000China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The Li-and Mn-rich layered oxides(R-LNCM)are considered as promising cathode materials for high-energy density lithium-ion batteries(LIBs).However,the interface side reaction aggravates the voltage and capacity fading between cathode material and electrolyte at high voltage,which severely hinders the practical application of LIB ***,lithium polyacrylate(LiPAA)as the binder and coating agent is applied to suppress the voltage and capacity fading of R-LNCM *** flexible LiPAA layers with high elasticity are capable of impeding cathode cracks on the particle surface via mechanical stress ***,superior voltage and capacity fading suppression on R-LNCM electrode is finally *** a result,LiPAA-R-LNCM cathode exhibits a remarkable specific capacity of 186 mA·h·g^(-1)with~73%retention at 1℃after ***,the corresponding average discharge potential is maintained to~3.1 V with only~0.4 V falling.

关键词： LiPAA interphase layer Interface side reaction Cathode cracks Capacity and voltage fading suppression Liand Mn-rich cathode

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