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Chinese Journal of Aeronautics 2024年第10期37卷 275-293页

作者： Qi YU Wanchun CHEN Wenbin YU school of Astronautics Beihang UniversityBeijing 102206China

In the scenario that a solid-fuel launch vehicle maneuvers in outer space at high angles of attack and sideslip for energy management,Approximate Analytical Solutions(AAS)for the threedimensional(3D)ascent flight states are derived,which are the only solutions capable of considering time-varying Mass Flow Rate(MFR)at *** uneven MFR makes the thrust vary nonlinearly and thus increases the difficulty of the problem *** AAS are derived based on a 3D Generalized Ascent Dynamics Model(GADM)with a normalized mass as the independent *** simplify some highly nonlinear terms in the GADM,several approximate functions are introduced carefully,while the errors of the approximations relative to the original terms are regarded as minor ***,a finite series with positive and negative exponents,called Exponent-Symmetry Series(ESS),is proposed for function approximation to decrease the highest exponent in the AAS so as to reduce computer round-off *** calculate the ESS coefficients,a method of seeking the Optimal Interpolation Points(OIP)is proposed using the leastsquares-approximation *** to the artful design of the approximations,the GADM can be decomposed into two analytically solvable subsystems by a perturbation method,and thus the AAS are obtained ***,to help implement the AAS,two indirect methods for measuring the remaining mass and predicting the burnout time in flight are put forward using information from *** results verify the superiority of the AAS under the condition of time-varying MFR.

关键词： Approximate analytical solutions 3D ascent trajectory Solid-fuel launch vehicle Uneven thrust Energy management

Free-walking:Pedestrian inertial navigation based on dual foot-mounted IMU

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Defence Technology（防务技术） 2024年第3期33卷 573-587页

作者： Qu Wang Meixia Fu Jianquan Wang Lei Sun Rong Huang Xianda Li Zhuqing Jiang Yan Huang Changhui Jiang school of Automation Science and Electrical Engineering University of Science and Technology BeijingBeijing100083China Shunde Innovation school University of Science and Technology BeijingFo Shan528399China Research Institute of china Unicom Beijing100190China school of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China Department of Automation Tsinghua University Beijing100084China GEOLOC Laboratory Universite Gustave EiffelParis77454France

The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time ***,the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with *** paper aims to enhance the accuracy of zero-velocity interval(ZVI)detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual *** at the observational noise problem of low-cost inertial sensors,we utilize a denoising autoencoder to automatically eliminate the inherent *** at the problem that inaccurate detection of the ZVI detection results in obvious displacement error,we propose a sample-level ZVI detection algorithm based on the U-Net neural network,which effectively solves the problem of mislabeling caused by sliding *** at the problem that Zero-Velocity Update(ZUPT)cannot suppress heading and altitude error,we propose a bipedal INS method based on the equation constraint and ellipsoid constraint,which uses foot-to-foot distance as a new observation to correct heading and altitude *** conduct extensive and well-designed experiments to evaluate the performance of the proposed *** experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance.

关键词： Indoor positioning Inertial navigation system(INS) Zero-velocity update(ZUPT) Internet of things(IoTs) Location-based service(LBS)

The Investigation of Data Voting Algorithm for Train Air-Braking System Based on Multi-Classification SVM and ANFIS

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Chinese Journal of Electronics 2024年第1期33卷 274-281页

作者： Juhan WANG Ying GAO Yuan CAO Tao TANG school of Electronics and Information Engineering Beijing Jiaotong University graduate Department China Academy of Railway Science National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University

The pressure data of the train air braking system is of great significance to accurately evaluate its operation state. In order to overcome the influence of sensor fault on the pressure data of train air braking system, it is necessary to design a set of sensor fault-tolerant voting mechanism to ensure that in the case of a pressure sensor fault, the system can accurately identify and locate the position of the faulty sensor, and estimate the fault data according to other normal data. A fault-tolerant mechanism based on multi-classification support vector machine(SVM) and adaptive network-based fuzzy inference system(ANFIS) is introduced. Multi-classification SVM is used to identify and locate the system fault state, and ANFIS is used to estimate the real data of the fault sensor. After estimation, the system will compare the real data of the fault sensor with the ANFIS estimated data. If it is similar,the system will recognize that there is a false alarm and record it. Then the paper tests the whole mechanism based on the real data. The test shows that the system can identify the fault samples and reduce the occurrence of false alarms.

关键词： Support vector machines Fault diagnosis Pressure sensors Fuzzy logic Fault tolerance Adaptive systems Fault tolerant systems

Temperature-sensing array using the metal-to-insulator transition of Nd_(x)Sm_(1-x)NiO_(3)

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1694-1700页

作者： Fengbo Yan Ziang Li Hao Zhang Yuchen Cui Kaiqi Nie Nuofu Chen Jikun Chen school of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China school of Renewable Energy North China Electric Power UniversityBeijing 102206China beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

Rare-earth nickelates(RENiO_(3))show widely tunable metal-to-insulator transition(MIT)properties with ignorable variations in lattice constants and small latent heat across the critical temperature(TMIT).Particularly,it is worth noting that compared with the more commonly investigated vanadium oxides,the MIT of RENiO_(3)is less abrupt but usually across a wider range of *** sheds light on their alternative applications as negative temperature coefficient resistance(NTCR)thermistors with high sensitivity compared with the current NTCR thermistors,other than their expected use as critical temperature resistance *** this work,we demonstrate the NTCR thermistor functionality for using the adjustable MIT of Nd_(x)Sm_(1-x)NiO_(3)within 200–400 K,which displays larger magnitudes of NTCR(e.g.,more than 7%/K)that is unattainable in traditional NTCR thermistor *** temperature dependence of resistance(R–T)shows sharp variation during the MIT of Nd_(x)Sm_(1-x)NiO_(3)with no hysteresis via decreasing the Nd content(e.g.,x≤0.8),and such a R–T tendency can be linearized by introducing an optimum parallel *** sensitive range of temperature can be further extended to 210–360 K by combining a series of Nd_(x)Sm_(1-x)NiO_(3)with eight rare-earth co-occupation ratios as an array,with a high magnitude of NTCR(e.g.,7%–14%/K)covering the entire range of temperatures.

关键词： rare-earth nickelates metal-to-insulator transition correlated oxides perovskites

Picroside Ⅱ promotes HSC apoptosis and inhibits the cholestatic liver fibrosis in Mdr2^(−/−)mice by polarizing M1 macrophages and balancing immune responses

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Chinese Journal of Natural Medicines 2024年第7期22卷 582-598页

作者： JIA Kexin MA Zhi ZHANG Yinhao XIE Kaihong LI Jianan WU Jianzhi QU Jiaorong LI Fanghong LI Xiaojiaoyang school of Life Sciences Beijing University of Chinese MedicineBeijing 100029China school of Chinese Materia Medica Beijing University of Chinese MedicineBeijing 100029China

Liver fibrosis is characterized by chronic inflammatory responses and progressive fibrous scar *** play a central role in the pathogenesis of hepatic fibrosis by reconstructing the immune *** Ⅱ(PIC Ⅱ),extracted from Picrorhizae Rhizoma,has demonstrated therapeutic potential for various liver ***,the mechanisms by which macrophage polarization initiates immune cascades and contributes to the development of liver fibrosis,and whether this process can be influenced by PIC Ⅱ,remain *** the current study,RNA sequencing and multiple molecular approaches were utilized to explore the underlying mechanisms of PIC Ⅱ against liver fibrosis in multidrug-resistance protein 2 knockout(Mdr2^(−/−))*** findings indicate that PIC Ⅱ activates M1-polarized macrophages to recruit natural killer cells(NK cells),potentially via the CXCL16-CXCR6 ***,PIC Ⅱ promotes the apoptosis of activated hepatic stellate cells(aHSCs)and enhances the cytotoxic effects of NK cells,while also reducing the formation of neutrophil extracellular traps(NETs).Notably,the anti-hepatic fibrosis effects associated with PIC Ⅱ were largely reversed by macrophage depletion in Mdr2^(−/−)***,our research suggests that PIC Ⅱ is a potential candidate for halting the progression of liver fibrosis.

关键词： Liver fibrosis PicrosideⅡ M1 macrophage Hepatic stellate cell Natural killer cell Neutrophil

N-doped graphene quantum dot-decorated N-TiO2/P-doped porous hollow g-C_(3)N_(4) nanotube composite photocatalysts for antibiotic photodegradation and H2 production

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 165-178页

作者： Jingshu Yuan Yao Zhang Xiaoyan Zhang Junjie Zhang Shen’gen Zhang Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China Xi’an Fanyi University Xi’an 710105China Shunde graduate school of University of Science and Technology beijing Foshan 528399China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao SAR 820000China

Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.

关键词： N-doped TiO_(2) N-doped graphene quantum dots P-doped g-C_(3)N_(4) porous hollow nanotube heterojunction photocatalysis

Diagnosing Thermalization Dynamics of Non-Hermitian Quantum Systems via GKSL Master Equations

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Chinese Physics Letters 2024年第7期41卷 1-11页

作者：毛奕廷钟佩耕林海青王孝群胡时杰 beijing Computational Science Research Center Beijing 100084China school of Physics Zhejiang UniversityHangzhou 310058China Department of Physics Beijing Normal UniversityBeijing 100875China

The application of the eigenstate thermalization hypothesis to non-Hermitian quantum systems has become one of the most important topics in dissipative quantum chaos, recently giving rise to intense debates. The process of thermalization is intricate, involving many time-evolution trajectories in the reduced Hilbert space of the system. By considering two different expansion forms of the density matrices adopted in the biorthogonal and right-state time evolutions, we derive two versions of the Gorini–Kossakowski–Sudarshan–Lindblad(GKSL)master equations describing the non-Hermitian systems coupled to a bosonic heat bath in thermal equilibrium. By solving the equations, we identify a sufficient condition for thermalization under both time evolutions, resulting in Boltzmann biorthogonal and right-eigenstate statistics, respectively. This finding implies that the recently proposed biorthogonal random matrix theory needs an appropriate revision. Moreover, we exemplify the precise dynamics of thermalization and thermodynamic properties with test models.

关键词： quantum implies precise

A N-CoSe/CoSe_(2)-C@Cu hierarchical architecture as a current collector-integrated anode for potassium-ion batteries

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Rare Metals 2024年第8期43卷 3702-3712页

作者： Zi-Jie Mu Yan-Jun Gao Wen-Shuai Dong Zong-You Li Qing-Yi Song Han-Jiao Huang Li-Dong Xing Jian-Guo Zhang Wei Wang Qi-Yao Yu State Key Laboratory of Explosion Science and Technology School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China school of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

The highly reversible insertion/extraction of large-radius K^+into electrode materials remains a tough goal,especially for con version-type ***,we design a current collector-integrated electrode(N-CoSe/CoSe_(2)-C@Cu) as an advanced anode for potassium-ion battery(PIBs).The conductive CoSe/CoSe_(2) heterojunction with rich Se vacancy defects,conductive sp^2 N-doped carbon layer,and the elastic copper foil matrix can greatly accelerate the electron transfer and enhance the structural ***,the well-designed N-CoSe/CoSe_(2)-C@Cu current collector-integrated electrode displays enhanced potassium storage performance with regard to a high capacity(325.1 mAh·g^(-1) at 0.1 A·g^(-1) after 200cycles),an exceptional rate capability(223.5 mAh·g^(-1) at2000 mA·g^(-1)),and an extraordinary long-term cycle stability(a capacity fading of only 0.019% per cycle over1200 cycles at 2000 mA·g^(-1)).Impressively,ex situ scanning electron microscopy(SEM) characterizations prove that the elastic structure of copper foil is merged into the cleverly designed N-CoSe/CoSe_(2)-C@Cu heterostructure,which buffers the deformation of structure and volume and greatly promotes the cycle life during the potassium/depotassium process.

关键词： Potassium-ion battery Integrated collector electrode CoSe CoSe_2 Heterojunction Copper foil matrix N-doped carbon

Unsupervised Multi-Expert Learning Model for Underwater Image Enhancement

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 708-722页

作者： Hongmin Liu Qi Zhang Yufan Hu Hui Zeng Bin Fan the school of Intelligence Science and Technology and the Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China the school of Automation and Electrical Engineering University of Science and Technology BeijingBeijing 100083China IEEE

Underwater image enhancement aims to restore a clean appearance and thus improves the quality of underwater degraded *** methods feed the whole image directly into the model for ***,they ignored that the R,G and B channels of underwater degraded images present varied degrees of degradation,due to the selective absorption for the *** address this issue,we propose an unsupervised multi-expert learning model by considering the enhancement of each color ***,an unsupervised architecture based on generative adversarial network is employed to alleviate the need for paired underwater *** on this,we design a generator,including a multi-expert encoder,a feature fusion module and a feature fusion-guided decoder,to generate the clear underwater ***,a multi-expert discriminator is proposed to verify the authenticity of the R,G and B channels,*** addition,content perceptual loss and edge loss are introduced into the loss function to further improve the content and details of the enhanced *** experiments on public datasets demonstrate that our method achieves more pleasing results in vision *** metrics(PSNR,SSIM,UIQM and UCIQE) evaluated on our enhanced images have been improved obviously.

关键词： Multi-expert learning underwater image enhancement unsupervised learning

Stimulating Start-up Investment Through Government-Sponsored Venture Capital:Theory and Chinese Evidence

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Journal of Systems Science & Complexity 2024年第5期37卷 2021-2053页

作者： NI Xuanming ZHENG Tiantian GAO Feng ZHAO Huimin school of Software and Microelectronics Peking UniversityBeijing 100871China school of Economics and Management Tsinghua UniversityBeijing 100084China school of Business Sun Yat-sen UniversityGuangzhou 510275China

Government-sponsored venture capital(GVC)has been used to support financially constrained start-ups as an important policy tool in ***,to motivate the social capital to invest in start-ups,GVC provides subsidies for them to bridge the funding gap in the early-stage venture capital ***,the effect and mechanism of GVC affecting social capital investment have not been clearly *** this paper,the authors not only develop a game model to analyze this issue in theory,but conduct an empirical study by analyzing the 14741 records matched by propensity score matching(PSM)of Chinese venture capital market data from 2011 to *** proposed findings are as the ***,the subsidies offered by GVC will simultaneously increase the returns and risks of investments in start-ups of social capital with more volatile incentive effect of *** incentive effect of GVC is only effective when the returns resulting from the subsidies outweigh the risks they *** the context of the Chinese venture capital market,the incentive effect of GVC is ***,the incentive effect of GVC is more pronounced in high-tech industries,which can be attributed to the signaling effect facilitated by *** this context,the subsidy mainly helps social capital to bear the costs associated with screening potential ***,the incentive effect of GVC is more significant in underdeveloped venture capital markets,which can be explained by the“virtuous cycle”effect,in which GVC plays a pioneering role in establishing a more robust early-stage market trading *** examining these three points,this study contributes to a better understanding of how GVC can effectively guide social capital investment,especially in the Chinese landscape.

关键词： Government-sponsored venture capital fund incentive effect social capital subsidy venture capital