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Computer Modeling in Engineering & Sciences 2024年第5期139卷 2175-2195页

作者： Jiawei shi Jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China

Combining the detached eddy simulation(DES)method and Ffowcs Williams-Hawkings(FW-H)equation,the effect of bogie cavity end wall inclination on the flow field and aerodynamic noise in the bogie region is numerically ***,the simulation is conducted based on a simplified cavity-bogie model,including five cases with different inclination angles of the front and rear walls of the *** comparing and analyzing the flow field and acoustic results of the five cases,the influence of the regularity and mechanism of the bogie cavity end wall inclination on the flow field and the aerodynamic noise of the bogie region are ***,the noise reduction strategy determined by the results of the simplified cavity-bogie model is applied to a three-car marshaling train model to verify its effectiveness when applied to the real *** results reveal that the forward inclination of the cavity front wall enlarges the influence area of shear vortex structures formed at the leading edge of the cavity and intensifies the interaction between the vortex structures and the front wheelset,frontmotor,and front gearbox,resulting in the increase of the aerodynamic noise generated by the bogie *** backward inclination of the cavity rear wall is conducive to guiding the vortex structures flow out of the cavity and weakening the interaction between the shear vortex structures and the cavity rear wall,leading to the reduction of the aerodynamic noise generated by the bogie *** the rear end wall of the foremost bogie cavity of the head car is a feasible aerodynamic noise reduction measure for high-speed trains.

关键词： Bogie cavity flow aerodynamic noise end wall inclination

Adaptive neural dynamic-based hybrid control strategy for stable retrieval of tethered satellite systems

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Astrodynamics 2024年第2期8卷 261-269页

作者： Zhixiong Ji Gefei shi School of Aeronautics and Astronautics Sun Yat-sen UniversityGuangzhou 510275China Shenzhen Campus of Sun Yat-sen University Shenzhen 518107China Shenzhen Key Laboratory of Intelligent Microsatellite Constellation Shenzhen 518107China

This study proposes a novel adaptive neural dynamic-based hybrid control strategy for stable subsatellite retrieval of two-body tethered satellite *** retrieval speed is given analytically,ensuring a libration-free steady *** mitigate the potential libration motion,a general control input signal is generated by an adaptive neural-dynamic(AND)algorithm and executed by adjusting the retrieval speed and thruster on the *** address the limited retrieval speed and improve the control performance,the thruster controller is manipulated according to a novel advanced state fuzzy control law based on higher-order libration states,whereas the remaining control input is allocated to the speed *** Lyapunov stability of the control strategy is demonstrated *** simulations validate the proposed control strategy,demonstrating well-allocated control inputs for both controllers and good control performance.

关键词： tethered satellite system(TSS) stable retrieval hybrid control adaptive neural-dynamic (AND)control fuzzy control

Cross-Modal Consistency with Aesthetic Similarity for Multimodal False Information Detection

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Computers, Materials & Continua 2024年第5期79卷 2723-2741页

作者： Weijian Fan Ziwei shi State Key Laboratory of Media Convergence and Communication Communication University of ChinaBeijing100024China Software Research Institute China United Network Communication Group Co.Ltd.Beijing100024China

With the explosive growth of false information on social media platforms, the automatic detection of multimodalfalse information has received increasing attention. Recent research has significantly contributed to multimodalinformation exchange and fusion, with many methods attempting to integrate unimodal features to generatemultimodal news representations. However, they still need to fully explore the hierarchical and complex semanticcorrelations between different modal contents, severely limiting their performance detecting multimodal falseinformation. This work proposes a two-stage detection framework for multimodal false information detection,called ASMFD, which is based on image aesthetic similarity to segment and explores the consistency andinconsistency features of images and texts. Specifically, we first use the Contrastive Language-Image Pre-training(CLIP) model to learn the relationship between text and images through label awareness and train an imageaesthetic attribute scorer using an aesthetic attribute dataset. Then, we calculate the aesthetic similarity betweenthe image and related images and use this similarity as a threshold to divide the multimodal correlation matrixinto consistency and inconsistencymatrices. Finally, the fusionmodule is designed to identify essential features fordetectingmultimodal false information. In extensive experiments on four datasets, the performance of the ASMFDis superior to state-of-the-art baseline methods.

关键词： Social media false information detection image aesthetic assessment cross-modal consistency

Distributed Optimal Formation Control for Unmanned Surface Vessels by a Regularized Game-Based Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 276-278页

作者： Jun shi Maojiao Ye the School of Automation Nanjing University of Science and TechnologyNanjing 210094China IEEE

Dear Editor,This letter explores optimal formation control for a network of unmanned surface vessels(USVs).By designing an individual objective function for each USV,the optimal formation problem is transformed into a noncooperative *** this game theoretic framework,the optimal formation is achieved by seeking the Nash equilibrium of the regularized game.A modular structure consisting of a distributed Nash equilibrium seeker and a regulator is proposed.

关键词： Regular seeking optimal

Vortex identification based on the Liutex method and its effect on fish passage upstream

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Journal of Hydrodynamics 2024年第1期36卷 130-141页

作者： Chun-ying Shen Rui-guo Yang Xiao-tao shi Ming-ming Wang shi-hua He Faculty of Electrical Power Engineering Kunming University of Science and TechnologyKunming650500China Hubei International Science and Technology Cooperation Base of Fish Passage China Three Gorges UniversityYichang443002China Shanghai Investigation Design and Research Institute Co.LtShanghai200434China

Fishway research is important for mitigating the fragmentation of river habitats caused by hydraulic *** vertical slit fishway is a broadly used fishway type because of its high efficiency and adaptability to water ***,the resulting vortex current disrupts the fish passage hence directly affecting fish *** study aims to accurately capture the vortex structure in the fishway and analyze the effect of vortex elements(vortex structure,vortex intensity,etc.)on *** conducted an analysis of the 3-D current flow field in the fishway through the utilization of an experimental model and the large eddy simulation(LES)***,we captured the vortex information in the fishway at different flow rates using the Liutex vortex identification method and investigated the effect of the vortex on fish *** results revealed that the structures inside the fishway pool occupy most of the room,however,the areas with higher vortex strength were primarily located in the vortex near the vertical seam and the mainstream,the vortex strength inside the fishway gradually increases with increasing flow,suppressing fish *** experienced significantly increased resistance when encountering strong *** suggests that the vortex may act as a physical barrier to fish *** findings highlight the potential negative effects of vortex on fish movement and reiterate the importance of understanding vortex dynamics for aquatic environmental *** an effective tool for identifying vortices in fluid flow,the Liutex method demonstrates features of vortex within the fishway,thereby providing important insights into the interaction between fluid dynamics and aquatic organisms.

关键词： Vertical slit fishway vortex identification method Liutex large eddy simulation(LES) fish experiment computational fluid dynamics

A highly sensitive multiple-mode optical thermometer designed in Eu^(2+/3+)and Li^(+)co-doped polymorphism compound LaSc_(3)(BO_(3))_(4)

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Journal of Advanced Ceramics 2024年第6期13卷 821-833页

作者： Nan Yang Zhuo Li Tingxia Zhou Ziwang Zhang Wen shi Yexiang Tong Jianxin shi School of Chemistry IGCMESun Yat-sen UniversityGuangzhou 510006China MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry IGCMEThe Key Lab of Low-Carbon Chemistry&Energy Conservation of Guangdong ProvinceSun Yat-sen UniversityGuangzhou 510006China

Noncontact optical thermometers have attracted widespread attention,but existing problems such as single-mode and low-sensitivity thermometers still urgently need to be ***,a novel multiple-mode thermometer was designed for the polymorphism LaSc_(3)(BO_(3))_(4):Eu^(2+/3+),Li^(+).X-ray diffraction(XRD)patterns revealed a slight transition betweenα-andβ-phases with the concentrations of the dopants,which is further proved by structure refinements and first-principles *** coexistence of Eu^(2+)and Eu^(3+)in the phosphors and their relative percentages were confirmed by X-ray absorption near-edge structure(XANES)*** from appropriate emissions from Eu^(2+)and Eu^(3+)without obvious energy transfer and their opposite changing trends with temperatures under 307 nm excitation,a triple-mode optical thermometer is obtained for this material within the temperature range of 150–450 *** highest sensitivities of 27.65,14.05,and 7.68%·K^(−1)are achieved based on two fluorescence intensity ratio(FIR)modes of Eu^(2+)and Eu^(3+)(5d–4f/^(5)D_(0)–^(7)F_(2,4))and the fluorescence lifetime(FL)mode of Eu^(2+),*** the best of our knowledge,the former is almost the highest in Eu^(2+)and Eu^(3+)co-doped *** results indicate that this material may be used as an excellent multiple-mode optical thermometer.

关键词： phase transition europium(Eu)ions multiple-mode optical thermometer thermal quenching properties fluorescence intensity ratio(FIR) fluorescence lifetime(FL)

Enantioselective Alkylation of Aldehydes with Organoborons Enabled by Nickel/N-Heterocyclic Carbene Catalysis

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Chinese Journal of Chemistry 2024年第18期42卷 2161-2165页

作者： Song-Yang Liu Zi-Chao Wang shi-Liang shi College of Chemistry and Material Science Shanghai Normal University100 Guilin RoadShanghai 200234China State Key Laboratory of Organometallic Chemistry Shanghai Institute of rganic ChemitryUniversity of Chinee Academy of Scienc Chinese Academy of Sciences345 Lingling RoadShanghai 200032China

Transition-metal-catalyzed asymmetric alkylation of aldehydes represents a straightforward strategy for the synthesis of chiral secondary ***,efficient methods using organoborons as coupling reagents are ***,we report a highly enantioselective nickel-catalyzed alkylation reaction of aldehydes,using readily available alkylborons as nucleophiles.A wide variety of chiral secondary alcohols were prepared from commercially available aldehydes with high *** key to the excellent enantioselectivity and chemoselectivity was the employment of a bulky C2-symmetric chiral NHC *** protocol features excellent enantiocontrol,mild conditions,and good functional group compatibility.

关键词： Enantioselective alkylation Nickel catalysis N-Heterocyclic carbene Organoborons Chiral alcohols Asymmetric catalysis C-C coupling Synthetic methods

Theory and test of underground explosions:Coupling rule between cratering and ground shock

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Underground Space 2024年第4期17卷 146-160页

作者： Wei Guo Jie Li Benjun shi Tianhan Xu Xiaohui Xu Gan Li Jie shi State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact Army Engineering University of PLANanjing 210007China

Calculating the parameters of the ground shock induced by an underground explosion is a complex energy coupling *** is difficult to establish a unified ground shock coupling law from limited test *** paper summarizes the research results obtained at home and abroad and systematically analyzes the coupling mechanism of craters formed by an underground explosion and the ground *** differences between the concepts of"closed-explosion critical depth"and"equivalent closed-explosion critical depth"are clearly *** spreading of the ground shock energy is attributed to the explosive expansion of the air cavity,revealing a linear relationship between the volume of the cavity region(or the volume of the crack region)and the ground shock energy associated with the underground *** proportionality factor is related to the mechanical properties of the medium and is independent of the magnitude of the explosion *** on this,a theoretical calculation formula and conversion method for the ground shock coupling coefficient were *** tests were conducted in clay and Plexiglass under varying burial *** test results were consistent with the theoretically calculated *** study provides a theoretical basis for the design of explosion-resistant structures in underground engineering.

关键词： Underground explosion Ground shock coupling Coupling coefficient Equivalent closed explosion Experimental study

Design strategies and recent advancements of solid-state supercapacitor operating in wide temperature range

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Carbon Energy 2024年第6期6卷 248-281页

作者： Jie Zhou Zhengfeng Zhu Wenhui shi Xiangyu shi Zhuoyuan Zheng Ye Xiong Yusong Zhu School of Energy Science and Engineering Nanjing Tech UniversityNanjingJiangsuChina Kucap Smart Technology(Nanjing)Co. Ltd.NanjingJiangsuChina

Solid-state supercapacitors(SSCs)are emerging as one of the promising energy storage devices due to their high safety,superior power density,and excellent cycling ***,performance degradation and safety issues under extreme conditions are the main challenges for the practical *** the expansion of human activities,such as space missions,polar exploration,and so on,the investigation of SSC with wide temperature tolerance,high energy density,power density,and sustainability is highly *** this review,the effects of temperature on SSC are systematically illustrated and clarified,including the properties of the electrolyte,ion diffusion,and reaction dynamics of the ***,we summarize the recent advances in wide-temperature-range SSCs from the aspect of electrolyte modification,electrode design,and interface adjustment between electrode and electrolyte,especially with critical concerns on ionic conductivity and cycling *** the end,a perspective is presented,expecting to promote the practical application of the SSC in harsh conditions.

关键词： electrode interface solid-state electrolyte solid-state supercapacitor wide temperature

Projections of summer light rain frequency in typical terrain over eastern China under wind speed constraint

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Science China Earth Sciences 2024年第6期67卷 1885-1894页

作者： Xuechen DONG Daoyi GONG Cuicui shi Institute of Disaster Risk Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster MOEFaculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China School of National Safety and Emergency Management Beijing Normal UniversityBeijing 100875China School of Systems Science Beijing Normal UniversityBeijing 100875China

The variation in near-surface wind speed is a key dynamic parameter in the orographic effect of precipitation over eastern *** this study,we used the latest high-resolution outputs from six GCMs in CMIP6-HighResMIP to evaluate the performance of high-resolution models in simulating the orographic precipitation characteristics of typical mountainous areas in summer over eastern *** orographic precipitation under warming scenarios was projected and constrained according to observational *** results indicated that during the contemporary climate reference period(1979-2009),although the relationship between model-simulated near-surface wind speed and orographic light rain frequency was consistently stable,the sensitivity of the orographic light rain frequency to surface wind variability was generally underestimated,with a deviation approximately 24.1% lower than the observational *** estimated orographic light rain frequency corrected based on the observed near-surface wind speed under a 1.5℃ warming scenario,was 36.1% lower than that of the contemporary period;this reduction was 8.6 times that without the wind speed constraint(4.2%).The MRI-AGCM3-2-S model,with a longer dataset,demonstrated relatively stable reductions in orographic light rain frequency under different warming scenarios(1.5℃,2℃,3℃,and 4℃)after the application of wind speed *** all cases,the reductions exceeded those for the predictions made without the wind speed constraint.

关键词： Frequency of orographic light rain HighResMIP High-resolution projection Observational constraint Eastern China