检索结果-南通市图书馆

Nuclear transport receptors underpin plastidial retrograde signaling

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2024年第7期17卷 993-995页

作者： Min jia Yangnan Gu Department of Plant and Microbial Biology University of CaliforniaBerkeleyBerkeleyCAUSA

The nucleus integrates cytosolic and organellar signals to regulate gene expression during plant stress responses,and this process is highly dependent on shuttling of signaling molecules in and out of the *** nucleocytoplasmic transport of macromolecules is facilitated by nuclear transport receptors(NTRs).NTRs are broadly categorized into exportins,which mediate the export of cargo from the nucleus to the cytoplasm,and importins,which facilitate the import of cargo into the *** importin family comprises importin-α(IMPa)and importin-β(IMPp).IMPa proteins are adaptor proteins and composed of three functional domains:an N-terminal IMPβ-binding(IBB)domain,ten Armadillo(ARM)repeats responsible for recognizing and interacting with cargo,and an exportin-interacting domain crucial for recycling via nuclear export(Wing et al.,2022).During a nuclear transport event,*** cargo containing a classical nuclear localization signal(cNLS)through its ARM repeats and engages IMPβvia its IBB domain,forming the cargo-IMPa-IMPβternary ***βfacilitates translocation of this complex through the nuclear *** inside the nucleus,RanGTP competes with IMPa for binding to IMPβ,promoting disassembly of the transport complex and releaseofcargo.

关键词： complex. integrate ternary

Comparison of electrochemical behaviors of Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe and Ti-6Al-4V titanium alloys in NaNO_(3) solution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 750-763页

作者： jia Liu Shuanglu Duan Xiaokang Yue Ningsong Qu College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The Ti-5Al-2Sn-4Zr-4Mo-2Cr-1Fe(β-CEZ)alloy is considered as a potential structural material in the aviation industry due to its outstanding strength and corrosion *** machining(ECM)is an efficient and low-cost technology for manufacturing theβ-CEZ *** ECM,the machining parameter selection and tool design are based on the electrochemical dissolution behavior of the *** this study,the electrochemical dissolution behaviors of theβ-CEZ and Ti-6Al-4V(TC4)alloys in NaNO3solution are *** open circuit potential(OCP),Tafel polarization,potentiodynamic polarization,electrochemical impedance spectroscopy(EIS),and current efficiency curves of theβ-CEZ and TC4 alloys are *** results show that,compared to the TC4 alloy,the passivation film structure is denser and the charge transfer resistance in the dissolution process is greater for theβ-CEZ ***,the dissolved surface morphology of the two titanium-based alloys under different current densities are *** low current densities,theβ-CEZ alloy surface comprises dissolution pits and dissolved products,while the TC4 alloy surface comprises a porous honeycomb *** high current densities,the surface waviness of both the alloys improves and the TC4 alloy surface is flatter and smoother than theβ-CEZ alloy ***,the electrochemical dissolution models ofβ-CEZ and TC4 alloys are proposed.

关键词： electrochemical machining dissolution behavior β-CEZ titanium alloy polarization curve current efficiency

Resilience assessment and optimization method of city road network in the post-earthquake emergency period

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第3期23卷 765-779页

作者： Wang Haoran Xiao jia Li Shuang Zhai Changhai Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information TechnologyHarbin Institute of TechnologyHarbin 150090China

The post-earthquake emergency period,which is a sensitive time segment just after an event,mainly focuses on saving life and restoring social *** improve the seismic resilience of city road networks,a resilience evaluation method used in the post-earthquake emergency period is *** road seismic damage index of a city road network can consider the influence of roads,bridges and buildings along the roads,*** road capacity after an earthquake.A function index for a city road network is developed,which reflects the connectivity,redundancy,traffic demand and traffic function of the *** optimization model for improving the road repair order in the post-earthquake emergency period is also developed according to the resilience evaluation,to enable decision support for city emergency management and achieve the best seismic resilience of the city road *** optimization model is applied to a city road network and the results illustrate the feasibility of the resilience evaluation and optimization method for a city road network in the post-earthquake emergency period.

关键词： city road network post-earthquake emergency period traffic demand resilience evaluation optimization model

Origin and evolution of false brinelling and fretting corrosion under rolling conditions

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 618-631页

作者： Xin jia Lu HUANG Miao SUN Wenbin LI National Institute of Metrology Beijing 100029China Yantai Tiancheng Machinery Co. Ltd.Yantai 264006China

Rolling bearings working in oscillating applications often suffer from false brinelling and fretting corrosion that limit their service *** present,the study of oscillation-induced failures is primarily dominated by a large number of sliding and bench ***,most of the previous work are not able to fully describe the two closely related but different failure *** this study,the origin and evolution of the two failures are thoroughly investigated under strictly controlled oscillating rolling *** results show that failure evolves from false brinelling to fretting corrosion under dry friction conditions regardless of the oscillation *** process is accompanied by a large area peeling and serious oxidation,and the oxygen content increases from 2.50 wt%to 21.22 wt%.Oxidation is a crucial factor in the evolution of false brinelling into fretting ***,the distribution of microwear and oxygen content depend on the oscillation *** lubrication conditions,the friction coefficient(COF)is smaller in the initial stage and led to local slip or transient instability of rolling ***,the size of the wear marks and COF increased and appeared to be larger than those under a dry friction ***,grease can separate the contact surfaces,only surface deformation owing to false brinelling and slight damage at the roughness level *** evolution of false brinelling and fretting corrosion is also closely related to residual *** brinelling often occurrs with residual stress accomulation,meanwhile,the residual stress increases from 120 to 300 *** peeling occurs,residual stress is *** failure pattern transformed from false brinelling to fretting corrosion and is accompanied by *** far,none of investigation is able to show satisfactory evolution of oscillating-induced failures,this study may contribute to more scientific understanding of rolling bearings against long-

关键词： oscillating false brinelling fretting corrosion wear residual stress

Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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 Iron and Steel Research International 2024年第3期31卷 767-777页

作者： Hong-bin Dai jian Miao jia-xin Lin School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property

A guidance and control design with reduced information for a dual-spin stabilized projectile

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 494-505页

作者： Yu Wang Jiyan Yu Xiaoming Wang jia Fangxiu Intelligent Ammunition Technology National Defense Key Discipline Laboratory Nanjing University of Science and TechnologyNanjingJiangsu210094China

In this paper,an integrated guidance and control method based on an adaptive path-following controller is proposed to control a spin-stabilized projectile with only translational motion information under the constraint of an actuator,uncertainties in aerodynamic parameters and measurements,and control system *** to the fairly high rotation speed,the dynamic model of this missile is strongly nonlinear,uncertain and coupled in pitch,yaw and roll channels.A theoretical equivalent resultant force and uncertainty compensation method are comprehensively used to realize decoupling of pitch and *** response to the strong nonlinear and time-varying characteristics of the dynamic system,the quasi-linear model whose parameters are obtained by interpolation of points selected as the segmentation points in the trajectory envelope,is used for calculation in each *** cope with the system uncertainty caused by model approximation,parameter uncertainty and ballistic interference,an extended state estimator is used to compensate the output feedback according to the test ballistic *** order to improve the tracking efficiency and ensure the tracking error convergence with only translational motion information,the virtual guide point,whose derivative is deduced according to the Lyapunov principle,is calculated in real time according to the projection relationship between the real-time position and the reference trajectory,and a virtual line-of-sight angle and the backstepping method are used for the design of the guidance and control *** order to avoid the influence of control input saturation on the guidance and control performance due to the actuator limitation and improve the robustness of the system,an anti-saturation compensator is designed according to the two-step *** feasibility and effectiveness of the path-following controller is verified through closed-loop flight simulations with measurement,control,and condition *** result

关键词： Spin-stabilized projectile Reduced information Path-following control Extended state observer Coupled nonlinear system Input saturation

Design of acceleration control schedule for adaptive cycle engine based on direct simulation model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第6期37卷 307-318页

作者： Keran SONG Linyuan jia Yuchun CHEN Tian TAN School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China

To design the optimum acceleration control schedule for the Adaptive Cycle Engine(ACE)in the full flight envelope,this paper establishes a direct simulation model of the ACE transient *** this model,geometric parameters are used to replace the component state *** corresponding relationship between geometric parameters and component state parameters is determined by sensitivity *** geometric variables are controlled when the geometric adjustment speed exceeds the limit,and at the same time the corresponding component state parameters are *** gradient optimization algorism is used to optimize the ground acceleration process of ACE,and the control schedule in terms of operating point of compression components and corrected acceleration rate is used as the full-envelope acceleration control schedule based on the similarity *** acceleration control schedules of the triple-bypass mode and the double-bypass mode are designed in this *** acceleration processes under various flight conditions are simulated using the acceleration control *** with the acceleration process with the linear geometric adjustment schedule,the acceleration performance of ACE is improved by the acceleration control schedule,with the impulse of the acceleration process of the triple-bypass mode being increased by 8.7%-12.3% and the impulse of the double-bypass mode acceleration process being increased by 11.8%-14.1%.

关键词： Adaptive Cycle Engine(ACE) Direct simulation method Acceleration Control schedule Full flight envelope

A robust implicit high-order discontinuous Galerkin method for solving compressible Navier-Stokes equations on arbitrary grids

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2024年第8期40卷 96-119页

作者： jia Yan Xiaoquan Yang Peifen Weng Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China College of Energy and Mechanical Engineering Shanghai University of Electric PowerShanghai200090China

The primary impediments impeding the implementation of high-order methods in simulating viscous flow over complex configurations are robustness and *** challenges impose significant constraints on computational efficiency,particularly in the domain of engineering *** address these concerns,this paper proposes a robust implicit high-order discontinuous Galerkin(DG)method for solving compressible Navier-Stokes(NS)equations on arbitrary *** method achieves a favorable equilibrium between computational stability and *** solve the linear system,an exact Jacobian matrix solving strategy is employed for preconditioning and matrix-vector generation in the generalized minimal residual(GMRES)*** approach mitigates numerical errors in Jacobian solution during implicit calculations and facilitates the implementation of an adaptive Courant-Friedrichs-Lewy(CFL)number increasing strategy,with the aim of improving convergence and *** further enhance the applicability of the proposed method for intricate grid distortions,all simulations are performed in the reference *** practice significantly improves the reversibility of the mass matrix in implicit calculations.A comprehensive analysis of various parameters influencing computational stability and efficiency is conducted,including CFL number,Krylov subspace size,and GMRES convergence *** computed results from a series of numerical test cases demonstrate the promising results achieved by combining the DG method,GMRES solver,exact Jacobian matrix,adaptive CFL number,and reference domain calculations in terms of robustness,convergence,and *** analysis results can serve as a reference for implicit computation in high-order calculations.

关键词： Discontinuous Galerkin method Exact Jacobian matrix GMRES solver Adaptive CFL number Reference domain High-order

Periapsis shift in spherically symmetric spacetimes and effects of electric interactions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第8期48卷 224-239页

作者： Qianchuan Wang Junji jia School of Physics and Technology Wuhan UniversityWuhan 430072China Department of Astronomy&MOE Key Laboratory of Artificial Micro-and Nano-structures School of Physics and TechnologyWuhan UniversityWuhan 430072China

The periapsis shift of charged test particles in arbitrary static and spherically symmetric charged spacetimes are *** perturbative methods,the near-circular approximation and post-Newtonian methods,are developed and shown to be very accurate when the results are determined to high *** near-circular approximation method is more precise when eccentricity e of the orbit is small,whereas the post-Newtonian method is more effective when orbit semilatus rectum p is *** from these two methods are shown to agree when both e is small and p is *** results are then applied to the Reissner-Nordström spacetime,the Einstein-Maxwell-dilation gravity,and a charged wormhole *** effects of various parameters on the periapsis shift,particularly that of the electrostatic interaction,are carefully *** periapsis shift data of the solar-Mercury are then used to constrain the charges of the Sun and Mercury,and the data of the Sgr A^(*)-S2 periapsis shift are used to determine,for the first time using this method,the constraints of the charges of Sgr A^(*)and S2.

关键词： periapsis shift orbital precession post-Newtonian approximation perturbative method