检索结果-南通市图书馆

Effect of Modulus Heterogeneity on the Equilibrium shape and stress Field ofαPrecipitate in Ti-6Al-4V

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & sciences 2024年第7期140卷 1017-1028页

作者： Di Qiu Rongpei shi Materials Genome Institute Shanghai UniversityShanghai200444China school of Materials science and Engineering Harbin Institute of TechnologyShenzhen518055China shanghai Frontier science Center of Mechanoinformatics Shanghai UniversityShanghai200444China Zhejiang Laboratory Hangzhou311100China

For media with inclusions(e.g.,precipitates,voids,reinforcements,and others),the difference in lattice parameter and the elastic modulus between the matrix and inclusions cause stress concentration at the *** stress fields depend on the inclusions’size,shape,and distribution and will respond instantly to the evolving *** study develops a phase-field model concerningmodulus *** effect of modulus heterogeneity on the growth process and equilibrium state of theαplate in Ti-6Al-4V during precipitation is ***αprecipitate exhibits strong anisotropy in shape upon cooling due to the interplay of the elastic strain and interfacial *** calculated orientation of the habit plane using the homogeneous modulus ofαphase shows the smallest deviation fromthat of the habit plane observed in the experiment,compared to the case where the homogeneous modulus ofβphase is *** addition,the equilibrium volume ofαphase within the systemusing homogeneousβmodulus exhibits the largest dependency on the applied *** stress fields across theα/βinterface are further calculated under the assumption of modulus heterogeneity and compared to those using homogeneous modulus of eitherαorβ*** study provides an essential theoretical basis for developing mechanics models concerning systems with heterogeneous structures.

关键词： Elastic heterogeneity habit plane stress field titanium phase-field simulation

Effect of Bogie Cavity End Wall Inclination on Flow Field and Aerodynamic Noise in the Bogie Region of High-speed Trains

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

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

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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)

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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 s.x.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

mRNA medicine:Recent progresses in chemical modification,design,and engineering

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第10期17卷 9015-9030页

作者： xiaowen Hou Jinjun shi Yuling xiao Department of Cardiology Zhongnan Hospital of Wuhan UniversitySchool of Pharmaceutical SciencesWuhan UniversityWuhan 430071China Center for Nanomedicine and Department of Anesthesiology Perioperative and Pain MedicineBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA

Messenger RNA(mRNA)is a type of RNA that carries genetic information from DNA to the ribosome,where it is translated into *** has emerged as a powerful platform for development of new types of medicine,especially after the clinical approval of COVID-19 mRNA *** modification and nanoparticle delivery have contributed to this success significantly by improving mRNA stability,reducing its immunogenicity,protecting it from enzymatic degradation,and enhancing cellular uptake and endosomal ***,substantial progresses have been made in new modification chemistries,sequence design,and structural engineering to generate more stable and efficient next-generation *** innovations could further facilitate the clinical translation of mRNA therapies and *** that numerous review articles have been published on mRNA nanoparticle delivery and biomedical applications over the last few years,we herein focus on overviewing recent advances in mRNA chemical modification,mRNA sequence optimization,and mRNA engineering(e.g.,circular RNA and multitailed mRNA),with the aim of providing new perspectives on the development of more effective and safer mRNA medicines.

关键词： mRNA self-amplifying RNA circular RNA multitailed mRNA chemical modification machine learning