检索结果-南通市图书馆

Effect of void nucleation on microstructure and stress state in aluminum alloy tailor-welded blank

Progress in Natural Science:materials International 2021年第1期31卷 77-85页

作者： L.Xing m.zhan P.F.Gao m.Li Y.D.Dong T.Y.Wang State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Key Laboratory of High Performance manufacturing for Aero Engine (Northwestern Polytechnical University) Ministry of Industry and Information Technology

The microscopic damage initiation characteristic in welded joint greatly determines the subsequent damage evolution and fracture behavior of aluminum alloy tailor-welded blank(TWB) during plastic forming. In this study, the interactive dependence of void nucleation on microstructure and stress state in the welded joint of a2219 aluminum alloy TWB was quantitatively explored by in-situ SEm testing. moreover, a micromechanical model based on actual microstructure was adopted to reveal the underlying mechanisms from the perspective of microscopic heterogeneous deformation. The results showed that three void nucleation mechanisms, including particle-cracking, interface-debonding and matrix-cracking, coexisted in the deformation at different microstructure regions and stress states. The nucleation strain of each mechanism mainly depended on the particle volume fraction, grain size and stress triaxiality. Besides, the proportions of particle-cracking and interfacedebonding greatly varied with the grain size and particle volume fraction, and the variation law changed with the stress state. The proportion of matrix-cracking had a weak dependence on the microstructure, while increased with the stress triaxiality decreasing. It made the damage initiation in aluminum alloy welded joint transit from particle-cracking dominance to matrix-cracking dominance with the stress triaxiality *** micromechanical modeling results suggested that the changes of evolutions and distributions of mises stress in particle, hydrostatic stress at interface and plastic strain in matrix with microstructure and stress state were responsible for the above effects.

关键词： Aluminum alloy Welded joint Void nucleation microstructure Stress state micromechanical model

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Gelfand-Kirillov Dimension and Reducibility of Scalar Generalized Verma modules for Classical Lie Algebras

引用

Acta mathematica Sinica,English Series 2024年第3期40卷 658-706页

作者： zhan Qiang BAI Jing JIANG School of mathematical Sciences Soochow UniversitySuzhou 215006P.R.China E-mail:zqbai@*** jjsd6514@***

Let g be a classical complex simple Lie algebra and q be a parabolic *** m be a generalized Verma module induced from a one dimensional representation of *** m is called a scalar generalized Verma *** this paper,we will determine the reducibility of scalar generalized Verma modules associated to maximal parabolic subalgebras by computing explicitly the Gelfand-Kirillov dimension of the corresponding highest weight modules.

关键词： Generalized Verma module Gelfand-Kirillov dimension Young tableau

来源：

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

miniaturized, Shared Electric and magnetic Dipole, Pattern Diversity IoT Antenna for Sub-6 GHz Applications

引用

Chinese Journal of Electronics 2024年第5期33卷 1224-1233页

作者： zhan WANG Yuandan DONG University of Electronic Science and Technology of China

By using a novel meta-resonator structure, a miniaturized, surface mountable, shared aperture, and hybrid electric/magnetic dipole pattern diversity antenna is proposed for Internet of things（IoT） applications. By exploring the shared electric（E-dipole） and magnetic dipole（m-dipole） structures, a novel T-shaped split-ring resonator（SRR） with even and odd modes is presented and studied by current distributions and equivalent *** and omnidirectional（monopole-like） patterns are achieved by exciting the m-dipole and E-dipole modes of the T-shaped SRR, respectively. To validate the proposed design, this shared aperture metamaterial-inspired pattern diversity antenna with a small size of 0.295λ0× 0.0065λ0× 0.115λ0is fabricated and measured. The measured overlapped-10 dB bandwidth is from 3.40 GHz to 3.63 GHz（7.0%, covering the LTE B42 band） and the port isolation is greater than 23 dB. Both two modes achieve a good radiation efficiency better than-0.79 d B（>83.0%）.

关键词： Antenna measurements Dipole antennas Surface mount technology Switches Size measurement Aperture antennas Internet of Things Electric/magnetic dipoles Internet of things (IoT) metamaterial-based/inspired antenna LOW-PROFILE PATCH ANTENNA RECONFIGURABLE ANTENNA mICROSTRIP ANTENNA RADIATION-PATTERN HIGH-GAIN FREQUENCY ARRAY

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Dislocation density-me diate d creep ageing behavior of an Al-Cu-Li alloy

引用

Journal of materials Science & Technology 2024年第7期174卷 204-217页

作者： Chang Zhou Lihua zhan Chunhui Liu minghui Huang College of mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of Precision manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China Light Alloys Research Institute Central South UniversityChangsha 410083China

Creep aging is well-known to be a time-dependent,coupled process of deformation and precipitation strengthening for age-hardening *** existing mechanisms are mainly attributed to those interac-tions between atomic diffusion and dislocation ***,an understanding of the relationship between dislocation density and a special multistage creep behavior,i.e.,double steady creep feature,is still far *** we investigate the effect of various dislocation density levels on such an abnormal multistage creep of an Al-Cu-Li *** find that the increased dislocation densities enable an apparent time decrease(from 6.2 h to 0.8 h)of their first steadyⅡ-*** yield strength of post-aged sam-ples increases from 425.0 mPa to 580.0 mPa while the corresponding elongation decreases from 12.3%to 7.3%for the creep-aged samples#1 to#*** results also reveal that a great difference in dislocation configuration,tailored by various density levels,results in varying creep processes of theⅡ-*** stage is closely related to the nucleation and early growth of T_(1)*** number densities(maximum:2.9×10^(19)m^(-3))and the average length(maximum:21.3 nm)of T_(1)precipitates are much smaller than those of the stable peak-aged T_(1)phases,suggesting that creepⅡ-stage of all three creep-aged samples is dominant by the nucleation and initial growth of those T_(1)*** study provides valuable insights into the dislocation density-mediated creep deformation of an Al-Cu-Li alloy.

关键词： Dislocation density Al-Cu-Li alloy Creep ageing T_(1)precipitation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Poverty Reduction in China: Experiences and measurement of Effects

引用

China Economist 2024年第1期19卷 103-126页

作者： zhan Wang Institute of Industrial Economics(IIE) Chinese Academy of Social Sciences(CASS)BeijingChina

This study employs the generalized method of moments(Gmm)and panel vector autoregression(PVAR)models for a multi-factor quantitative dissection of China’s poverty reduction process across multiple stages,using provincial panel data from 2000 to *** to our research,economic growth and social development are the key drivers of poverty reduction in China,but the trickle-down effect of economic growth is diminishing and marketization is having a lesser pro-poor *** expenditure has failed to provide social protection and income redistribution benefits due to issues such as targeting error and elite *** the efficiency of the poverty reduction system calls for adaptive ***,this study highlights China’s poverty reduction experiences and analyzes current challenges,which serve as inspiration for consolidating poverty-reduction achievements,combating relative poverty,and attaining countryside vitalization.

关键词： Poverty reduction governance measurement of effects countryside vitalization common prosperity

来源：

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

Rationally designed synthetic peptide as versatile calibrant to improve the accuracy of protein sequence analysis using mALDI mass spectrometry

引用

Chinese Chemical Letters 2024年第3期35卷 214-220页

作者： Lingpeng zhan Yanyi Huang Guanbo Wang Institute for Cell Analysis Shenzhen Bay LaboratoryShenzhen 518132China Biomedical Pioneering Innovation Center Peking UniversityBeijing 100871China

matrix-assisted laser desorption/ionization(mALDI)mass spectrometry(mS)plays an indispensable role in analyzing protein covalent *** reliable identification of amino acid residues and modifications relies on the mass accuracy,which is highly dependent on ***,the accuracy provided by the currently available calibrants still needs further improvement in terms of compatibility with multiple tandem mS modes or ion polarity modes,calibratable range,and minimizing suppression of and interference with analyte *** aiming at developing a versatile calibrant to solve these problem,we designed a synthetic peptide format of calibrant R_x(GDP_n)_m(referred to as“Gly-Asp-Pro,GDP”)according to the chemical natures of amino acids and polypeptide fragmentation rules in tandem *** four types of amino acid residues selected and arranged through rational designs,a GDP peptide produces highly regulated fragments that give rise to evenly spaced signals in each tandem mS mode and is compatible with both positive and negative ion *** internal calibration,its regulated fragmentation pattern minimizes interference with analyte signals,and using a single peptide as the input minimizes suppression of the analyte *** demonstrated by analyses of proteins including monoclonal antibody and Aβ-42,these features allowed significant increase of the mass accuracy and precision,which improved sequence coverage and sequence resolution in sequence analyses(including de novo sequencing).This rational design strategy may also inspire further development of synthetic calibrants that benefit structural analysis of biomolecules.

关键词： Biomolecule design Synthetic peptide Protein sequencing Covalent structure De novo sequencing mass spectrometry Gas-phase fragmentation

来源：

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

Electro-optic 3D snapshot of a laser wakefield accelerated kilo-ampere electron bunch

引用

Light(Science & Applications) 2024年第5期13卷 823-834页

作者： Kai Huang zhan Jin Nobuhiko Nakanii Tomonao Hosokai masaki Kando Kansai Institute for Photon Science(KPSI) National Institutes for Quantum Science and Technology(QST)KyotoJapan. Laser Accelerator R&D Innovative Light Sources DivisionRIKEN SPring-8 CenterHyogoJapan. SANKEN Osaka UniversityOsakaJapan

Laser wakefield acceleration,as an advanced accelerator concept,has attracted great attentions for its ultrahigh acceleration gradient and the capability to produce high brightness electron *** three-dimensional(3D)density serves as an evaluation metric for the particle bunch quality and is intrinsically related to the applications of an *** its significance,this parameter has not been experimentally measured in the investigation of laser wakefield *** report on an electro-optic 3D snapshot of a laser wakefield electron bunch at a position outside the *** 3D shape of the electron bunch was detected by simultaneously performing optical transition radiation imaging and electro-optic *** 3D structures to a few micrometer levels were reconstructed using a genetic *** electron bunch possessed a transverse size of less than 30 *** current profile shows a multi-peak *** main peak had a duration of1 *** maximum electron 3D number density was~9×10^(21)m^(-3).This research demonstrates a feasible way of 3D density monitoring on femtosecond kilo-ampere electron bunches,at any position of a beam transport line for relevant applications.

关键词： laser acceleration field

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Reduced-complexity multiple parameters estimation via toeplitz matrix triple iteration reconstruction with bistatic mImO radar

引用

Chinese Journal of Aeronautics 2024年第7期37卷 482-495页

作者： Chenghong zhan Guoping HU Junpeng SHI Fangzheng ZHAO Hao ZHOU Graduate College Air Force Engineering UniversityXi’an 710051China Air and missile Defense College Air Force Engineering UniversityXi’an 710051China College of Electronic Countermeasure National University of Defense TechnologyHefei 230037China Beijing Aeronautical Technology Research Center Beijing 100076China

In this advanced exploration, we focus on multiple parameters estimation in bistatic multiple-Input multiple-Output(mImO) radar systems, a crucial technique for target localization and imaging. Our research innovatively addresses the joint estimation of the Direction of Departure(DOD), Direction of Arrival(DOA), and Doppler frequency for incoherent targets. We propose a novel approach that significantly reduces computational complexity by utilizing the TemporalSpatial Nested Sampling model(TSNSm). Our methodology begins with a multi-linear mapping mechanism to efficiently eliminate unnecessary virtual Degrees of Freedom(DOFs) and reorganize the remaining ones. We then employ the Toeplitz matrix triple iteration reconstruction method, surpassing the traditional Temporal-Spatial Smoothing Window(TSSW) approach, to mitigate the single snapshot effect and reduce computational demands. We further refine the highdimensional ESPRIT algorithm for joint estimation of DOD, DOA, and Doppler frequency, eliminating the need for additional parameter pairing. moreover, we meticulously derive the Cramér-Rao Bound(CRB) for the TSNSm. This signal model allows for a second expansion of DOFs in time and space domains, achieving high precision in target angle and Doppler frequency estimation with low computational complexity. Our adaptable algorithm is validated through simulations and is suitable for sparse array mImO radars with various structures, ensuring higher precision in parameter estimation with less complexity burden.

关键词： mImO Radar multipleparameters estimation Temporal-spatial Nested Sampling multi-linear mapping mechanism Toeplitz matrix triple iteration reconstruction Reduce computational complexity

来源：

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

Stabilizing iridium sites via interface and reconstruction regulations for water oxidation in alkaline and acidic media

引用

Journal of Energy Chemistry 2024年第2期89卷 355-363,I0009页

作者： Weibin Chen Yanhui Song Lei Li Junjie Guo zhan Lin Guangdong Provincial Key Laboratory of Plant Resources Biorefinery School of Chemical Engineering and Light IndustryGuangdong University of TechnologyGuangzhou 510006GuangdongChina Key Laboratory of Interface Science and Engineering in Advancedmaterials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024ShanxiChina

Exploring effective iridium(Ir)-based electrocatalysts with stable iridium centers is highly desirable for oxygen evolution reaction(OER).Herein,we regulated the incorporation manner of Ir in Co_(3)O_(4)support to stabilize the Ir sites for effective *** anchored on the surface of Co_(3)O_(4)in the form of Ir(OH)_6 species,the created Ir-OH-Co interface leads to a limited stability and poor acidic OER due to Ir *** doped into Co_(3)O_(4)lattice,the analyses of X-ray absorption spectroscopy,in-situ Raman,and OER measurements show that the partially replacement of Co in Co_(3)O_(4)by Ir atoms inclines to cause strong electronic effect and activate lattice oxygen in the presence of Ir-O-Co interface,and simultaneously master the reconstruction effect to mitigate Ir dissolution,realizing the improved OER activity and stability in alkaline and acidic *** a result,Ir_(lat)@Co_(3)O_(4)with Ir loading of 3.67 wt%requires 294±4 mV/285±3 mV and 326±2 mV to deliver 10 mA cm^(-2)in alkaline(0.1 m KOH/1.0 m KOH)and acidic(0.5 m H_(2)SO_(4))solution,respectively,with good stability.

关键词： Interface effect Reconstruction Ir dissolution Ir-O-Co Oxygen evolution reaction

来源：

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

Coherence entropy during propagation through complex media

引用

Advanced Photonics 2024年第4期6卷 25-35页

作者： Xingyuan Lu Zhuoyi Wang Qiwen zhan Yangjian Cai Chengliang Zhao Soochow University School of Physical Science and TechnologyJiangsu Key Laboratory of Frontier Material Physics and DevicesSuzhouChina University of Shanghai for Science and Technology School of Optical-Electrical and Computer EngineeringShanghaiChina Shandong Normal University School of Physics and ElectronicsShandong Provincial Engineering and Technical Center of Light ManipulationsShandong Provincial Key Laboratory of Optics and Photonic DeviceJinanChina East China Normal University Joint Research Center of Light Manipulation Science and Photonic Integrated Chip of East China Normal University and Shandong Normal UniversityShanghaiChina

The deformation,flicker,and drift of a light field owing to complex media such as a turbulent atmosphere have limited its practical ***,research on invariants in randomly fluctuated light fields has garnered considerable attention in recent *** is a statistical property of light,while its full and quantitative characterization is ***,we successfully realize the orthogonal modal decomposition of partially coherent beams and introduce the application of coherence entropy as a global coherence characteristic of such randomly fluctuated light *** is demonstrated that coherence entropy remains consistent during propagation in a unitary system by unraveling complex *** representative examples,we study the robustness of coherence entropy for partially coherent beams as they propagate through deformed optical systems and turbulent *** entropy is anticipated to serve as a key metric for evaluating the propagation of partially coherent beams in complex *** study paves the way for a broader application scope of a customized low-coherence light field through nonideal optical systems and complex media.

关键词： complex media propagation invariant modal decomposition orbital angular momentum statistical optics coherence

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：