检索结果-南通市图书馆

Transition of dynamic recrystalliz.tion mechanism during hot deformation of Incoloy 028 alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第7期42卷 241-253页

作者： XiTing z.ong lei Wang Link. Huang Feng Liu State k.y Lab of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China State k.y Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi'an710077China Analytical&Testing Center Northwestern Polytechnical UniversityXi’an710072China

Dynamic recrystalliz.tion(DRX)plays significant roles in manipulating of microstructures during hot deformation and the result mechanical properties;however,the underling mechanism leading to multi scale-microstructures remains poorly ***,the DRX mechanism under wide processing conditions(i.e.950-1200°C,0.001-10 s-1)in Incoloy 028 alloy was investigated,where the relationships among flow stress,z.parameter and grain siz.,as well as the evolution of characteristic microstructures(grain siz.,sub-grain boundaries,and high angle grain boundaries),are *** the values of z.parameters decrease(corresponding to decreased flow stresses),three typical softening mechanisms successively occur,ranging from continuous DRX controlled by dislocation glide,discontinuous DRX dominated by dislocation motion(climb and cross/multiple slip)and grain boundary migration,to dynamic normal/abnormal grain growth resulting from grain boundary migration,with transition regions where two adjacent mechanisms occur ***,these above three softening mechanisms result in ultrafine,fine and coarse grains,*** present findings demonstrate a comprehensive understanding of DRX mechanism over a wide range of processing conditions,and further provide a new guideline for preparing single crystals.

关键词： Hot deformation Dynamic recrystalliz.tion Microstructure evolution Incoloy 028

Effects of Thermally Assisted Warm Laser Shock.Processing on the Microstructure and Fatigue Property of IN718 Superalloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2021年第12期34卷 1645-1656页

作者： Yang Liu lei Wang k.iyue Yang Xiu Song The k.y Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China

The effects of laser shock.processing(LSP)and warm laser shock.processing(WLSP)on the microstructure of surface hardening layer and high-cycle fatigue performance at room temperature and high temperature(600°C)of IN718 alloy were *** has been revealed that the grain refined hardening layer with greater residual compression stresses,higher fraction of coincidence site lattice(CSL)boundaries and dislocation densities was formed in WLSP-treated alloy than in LSP-treated ***,microtwins includedγ″phase/high density dislocation complex was found in the surface of WLSP-treated *** characters caused the significant enhancement of the medium value fatigue strength of WLSP-treated alloy at room temperature and elevated ***,the microtwins includedγ″phase/high density dislocation complex formed in the surface hardening layer of LSP-treated alloy has more complicated steric structure and more stable at elevated temperature thanγ″phase/low density dislocation complex formed in LSP-treated alloy,leading to the slow recovery ***,the surface hardening layer in the WLSP-treated alloy remained more ideal strengthening effect under high-cycle fatigue at elevated temperature than that in LSP-treated *** resulted in the much longer fatigue crack.initiation incubation and longer high-cycle life of WLSP-treated IN718 alloy under cycling load at 600℃.This discovery provides a new cognition of fatigue resistance by WLSP treatment of precipitation strengthening superalloy.

关键词： IN718 superalloy Warm laser shock.processing(WLSP) Microstructure Fatigue Residual stress

Rectangling irregular videos by optimal spatio-temporal warping

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2022年第1期8卷 93-103页

作者： Jin-Liang Wu Jun-Jie Shi lei z.ang The 54th Research Institute of CETC Shijiazhuang 050050China School of Computer Science Beijing Institute of TechnologyBeijing 100081China.

Image and video processing based on geometric principles typically changes the rectangular shape of video frames to an irregular shape. This paper presents a warping based approach for rectangling such irregular frame boundaries in space and time, i.e., mak.ng them rectangular again. To reduce geometric distortion in the rectangling process, we employ contentpreserving deformation of a mesh grid with line structures as constraints to warp the frames. To conform to the original inter-frame motion, we k.ep feature trajectory distribution as constraints during motion compensation to ensure stability after warping the frames. Such spatially and temporally optimiz.d warps enable the output of regular rectangular boundaries for the video frames with low geometric distortion and jitter. Our experiments demonstrate that our approach can generate plausible video rectangling results in a variety of applications.

关键词： rectangling warping content-preserving

Synthesis,Crystal Structure and Photoluminescence of a One-dimensional z.nc(Ⅱ)Coordination Polymer with Substituted Terpyridine

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2010年第7期29卷 1098-1102页

作者： GOU lei LI Dong-Lin School of Materials Science and Engineering Chang'an University Xi'an Shaanxi 710061 China College of Chemistry and Materials Science Northwest University Xi'an Shaanxi 710069 China

The title compound, [z.（4-pytpy）（NO3）2] （4-pytpy = 4′-（4-pyridyl）-2,2′：6′,2＂- terpyridine） 1, has been synthesiz.d by the solvothermal reaction of z.（NO3）2·6H2O with 4-pytpy in CH3OH solution. It crystalliz.s in the triclinic system, space group P1 with a = 8.358（6）, b = 11.121（8）, c = 11.374（8）A, α = 74.226（11）, β = 74.532（11）, γ = 83.085（12）°, Mr= 499.74, V= 979.3（12） A3, z.= 2, Dc = 1.695 g/cm3, F（000） = 508,μ = 1.309 mm^-1, the final R = 0.0547 and wR = 0.1588. X-ray crystal structure analysis revealed that the z.n is hexa-eoordinated by two oxygen atoms from two nitrate groups and four nitrogen atoms, three of which are from the tridentate domain of one 4-pytpy and the other from the monodentate domain of another 4-pytpy. 4-pytpy as a bridging ligand connects z.Ⅱ into a one-dimensional coordination polymer.

关键词： z.nc(Ⅱ) complex crystal structure terpyridine,solvothermal reaction luminescentproperty

H2A Variants in Arabidopsis: Versatile Regulators of Genome Activity

在线全文

学校读者我要写书评

暂无评论

Plant Communications 2020年第1期1卷 82-94页

作者： Bingk.n lei Frederic Berger Gregor Mendel Institute of Molecular Plant Biology Austrian Academy of SciencesVienna BioCenterDr.Bohr-Gasse 31030 ViennaAustria

The euk.ryotic nucleosome prevents access to the *** evolving histone isoforms,also called histone variants,form diverse families that are enriched over distinct features of plant *** the diverse families of plant histone variants,H2A.z.exclusively mark. *** we review recent research progress on the genome-wide distribution patterns and deposition of H2A.z.in plants as well as its association with histone modifications and roles in plant chromatin *** also discuss some hypotheses that explain the different findings about the roles of H2A.z.in plants.

关键词： histone H2A.z transcription Arabidopsis histone variant histone modifications

Real-time evaluation method of flight mission load based on sensitivity analysis of physiological factors

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 Journal of Aeronautics 2022年第3期35卷 450-463页

作者： Jun CHEN lei XUE Jia RONG Xudong GAO School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Department of Data Science and AI Monash UniversityClaytonVIC 3800Australia

As the complexity of flight missions continues to increase,sending a timely warning or providing assistance to pilots helps to reduce the probability of operational errors and flight *** pilots’physiological data,real-time evaluation of mission load is a feasible technical way to achieve *** this paper,a set of flight task. including aircraft control,humancomputer interaction and mental arithmetic tests are designed to simulate five mission loads at different flight difficulty levels.A sensitivity analysis method based on a comprehensive test is proposed to select a set of sensitive physiological ***,based on the SVM hierarchical combination classification method,the pilot mission load real-time evaluation model is *** test results show significant differences in EMG,respiration rate(abdomen),heart rate,blood oxygen saturation,pupil area,fixation duration,number of fixations,and *** high accuracy obtained from experiments proved that the proposed real-time evaluation model is applicable to meet the requirements of real work.ng *** findings can provide methodological references for mission load evaluation research in other fields.

关键词： Eye movement Mission load Physiological data Sensitivity analysis Support Vector Machine(SVM)

Atomistic Insights into the Irradiation Resistance of Co-Free High Entropy Alloy FeMnNiCr

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第10期37卷 1657-1666页

作者： Chunhui Wang lei Guo Rui Li Qing Peng School of Mechanical Engineering University of Science and Technology BeijingBeijing100083China State k.y Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China Guangdong Aerospace Research Academy Guangzhou511458China

We have investigated the displacement cascade irradiation resistance behavior of a cobalt-free high entropy alloy FeMnNiCr using molecular dynamics *** results show that defects in FeMnNiCr form in small clusters,and their migration is significantly inhibited,leading to a higher defect recombination rate and a lower number of residual defects compared to ***,FeMnNiCr exhibits a longer thermal peak.life and lower thermal conductivity compared to Ni,providing a longer time for defect migration and *** migration of defect clusters in FeMnNiCr displays three-dimensional properties,attributed to its high chemical *** prolonged irradiation,defects in FeMnNiCr stabiliz. as small clusters,whereas point defects in Ni tend to form large defect clusters and evolve into *** the feature of absence of the element cobalt,our results imply that FeMnNiCr has great potential in application in nuclear energies.

关键词： High entropy alloys Displacement cascade Irradiation defects Molecular dynamics

Composition optimiz.tion, high-temperature stability, and thermal cycling performance of Sc-doped Gd_(2)z._(2)O_(7) thermal barrier coatings: Theoretical and experimental studies

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 2022年第3期11卷 454-469页

作者： lei GUO Bowen LI Yuxian CHENG Lu WANG School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin k.y Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin 300072China AECC Shenyang Liming Aero-Engine Co. Ltd.Shenyang 110043China

Sc was doped into Gd_(2)z._(2)O_(7) for expanding the potential for thermal barrier coating (TBC) applications. The solid solution mechanism of Sc in the Gd_(2)z._(2)O_(7) lattice, and the mechanical and thermophysical properties of the doped Gd_(2)z._(2)O_(7) were systematically studied by the first-principles method, based on which the Sc doping content was optimiz.d. Additionally, Sc-doped Gd_(2)z._(2)O_(7) TBCs with the optimiz.d composition were prepared by air plasma spraying using YSz.as a bottom ceramic coating (Gd-Sc/YSz.TBCs), and their sintering behavior and thermal cycling performance were examined. Results revealed that at low Sc doping levels, Sc has a large tendency to occupy the lattice interstitial sites, and when the doping content is above 11.11 at%, Sc substituting for Gd in the lattice becomes dominant. Among the doped Gd_(2)z._(2)O_(7), the composition with 16.67 at% Sc content has the lowest Pugh’s indicator (G/B) and the highest Poisson ratio (σ) indicative of the highest toughness, and the decreasing trends of Debye temperature and thermal conductivity slow down at this composition. By considering the mechanical and thermophysical properties comprehensively, the Sc doping content was optimiz.d to be 16.67 at%. The fabricated Gd-Sc coatings remain phase and structural stability after sintering at 1400 ℃ for 100 h. Gd-Sc/YSz.TBCs exhibit excellent thermal shock.resistance, which is related to the good thermal match between Gd-Sc and YSz.coatings, and the buffering effect of the YSz.coating during thermal cycling. These results revealed that Sc-doped Gd_(2)z._(2)O_(7) has a high potential for TBC applications, especially for the composition with 16.67 at% Sc content.

关键词： thermal barrier coating(TBC) first-principles calculation solid solution mechanism high-temperature stability thermal cycling

Multi-task.regression learning for survival analysis via prior information guided transductive matrix completion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2020年第5期14卷 99-112页

作者： lei Chen k.i Shao Xianz.ong Long Lingsheng Wang Jiangsu k.y Laboratory of Big Data Security and Intelligent Processing Nanjing University of Posts and TelecommunicationsNanjing210023China MIIT k.y Laboratory of Pattern Analysis and Machine Intelligence Nanjing University of Aeronautics and AstronauticsNanjing211106China

Survival analysis aims to predict the occurrence time of a particular event of interest,which is crucial for the prognosis analysis of ***,due to the limited study period and potential losing track.,the observed data inevitably involve some censored instances,and thus brings a unique challenge that distinguishes from the general regression *** addition,survival analysis also suffers from other inherent challenges such as the high-dimension and small-sample-siz. *** address these challenges,we propose a novel multi-task.regression learning model,i.e.,prior information guided transductive matrix completion(PigTMC)model,to predict the survival status of the new ***,we use the multi-label transductive matrix completion framework.to leverage the censored instances together with the uncensored instances as the training samples,and simultaneously employ the multi-task.transductive feature selection scheme to alleviate the overfitting issue caused by high-dimension and small-sample-siz. *** addition,we employ the prior temporal stability of the survival statuses at adjacent time intervals to guide survival ***,we design an optimiz.tion algorithm with guaranteed convergence to solve the proposed PigTMC ***,the extensive experiments performed on the real microarray gene expression datasets demonstrate that our proposed model outperforms the previously widely used competing methods.

关键词： survival analysis matrix completion multi-task.regression transductive learning multi-task.feature selection