检索结果-南通市图书馆

Effect of Zr on undissolved phases and carbide precipitation in Ti microalloyed low-carbon steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2019年第7期26卷 720-732页

作者： Peng-cheng Liu Jian-chun Cao Shu-biao yin yin-hui yang Peng Gao Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Kunming 650093 Yunnan China

The undissolved phases and carbide precipitation in Ti and Ti-Zr microalloyed low-carbon steels were investigated by scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometry. At 1225℃, the replacement of Ti by Zr formed Zr2CS and (Zr, Ti)N (the Ti/Zr atomic ratio is 0.11) and reduced the consumption of Ti. At 925℃, it was identified that TiC phases were precipitated at first and Zr was incorporated into the TiC lattice in the subsequent precipitation process, which promoted the precipitation of titanium carbide. The calculation of the interaction coefficient between Ti, C, N and Zr showed that Zr reduced the activity of Ti and C and increased the activity of N in the iron matrix. Therefore, with the addition of Zr, the solubility of Ti was increased, and the consumption of Ti was reduced at high temperature in Ti microalloyed low-carbon steel. The thermodynamic calculation of carbide precipitation transformation showed that the replacement of Ti by Zr increased the nucleation driving force and the nucleation rate of titanium carbide, while the critical core size and the critical nuclear energy were reduced. As the holding time was extended, the Zr/ Ti atomic ratio increased and the size of the precipitates also increased. When the Zr/Ti atomic ratio reached a certain level, the size of the precipitates did not increase with further increase in atomic ratio. When the Zr/Ti atomic ratio in (Ti, Zr)C was 0.05-0.17,(Ti, Zr)C was the most stable carbide and the easiest to nucleate at 925℃. There was more of the (Ti, Zr)C phase than TiC at 925 ℃ after 50 and 100 s, and the time to complete the coarsening behavior of (Ti, Zr)C was shorter than that of TiC.

关键词： Ti-Zr microalloyed steel Undissolved phase Carbide precipitation Zirconium Thermodynamics

Convergence Analysis of Legendre-Collocation Methods for Nonlinear Volterra Type Integro Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2015年第1期7卷 74-88页

作者： yin yang Yanping Chen Yunqing Huang Wei yang Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan UniversityXiangtan 411105China School ofMathematical Sciences South China Normal UniversityGuangzhou 510631China

A Legendre-collocation method is proposed to solve the nonlinear Volterra integral equations of the second *** provide a rigorous error analysis for the proposed method,which indicate that the numerical errors in L2-norm and L¥-norm will decay exponentially provided that the kernel function is sufficiently *** results are presented,which confirm the theoretical prediction of the exponential rate of convergence.

关键词： Spectral method nonlinear Volterra integral equations

Risk analysis for a cascade reservoir system using the brittle risk entropy method

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(Technological Sciences) 2016年第6期59卷 882-887页

作者： yang yin REN Qing Wen TIAN ying XIONG Yao College of Hydraulic Conservation and Hydropower Engineering Hohai University Department of Engineering Mechanics Hohai University

The principal means of conserving water and utilizing hydropower in China is to exploit the use of a series of reservoirs in a cascade. This method and its inherent engineering safety problems are receiving increasing attention nowadays. In the field of engineering safety analysis, much work has focused on single reservoir projects in the past few years, but there is little research available on the safety risk analysis of cascade reservoirs, either within China or internationally. Therefore, a framework for risk analysis on the cascade reservoir system based on the theory of system engineering is constructed in this article. A cascading failure model is established and the connection degree factor discussed. In addition, the importance degree of the subsystem, which can be calculated by combining the analytical hierarchy process and the entropy weight method, is explained. According to brittleness theory of a complex system, brittle risk entropy is proposed as a performance index for measuring the collapse uncertainty of the cascade reservoir system. In addition, the brittle risk of the cascade reservoir system is predicted, which provides a reference for safety analysis in water conservation and hydropower construction projects in China.

关键词： cascading failure model safety analysis risk assessment complex system brittle risk entropy

Jacobi Spectral Collocation Method Based on Lagrange Interpolation Polynomials for Solving Nonlinear Fractional Integro-Differential Equations

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2018年第6期10卷 1440-1458页

作者： Xingfa yang yin yang Yanping Chen Jie Liu State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082HunanChina Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing&Information Processing of Ministry of EducationSchool of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105HunanChina School of Mathematical Sciences South China Normal UniversityGuangzhou 510631GuangdongChina Center for Research on Leading Technology of Special Equipment School of Mechanical and Electric EngineeringGuangzhou UniversityGuangzhou 510006GuangdongChina

In this paper,we study a class of nonlinear fractional integro-differential equations,the fractional derivative is described in the Caputo *** the properties of the Caputo derivative,we convert the fractional integro-differential equations into equivalent integral-differential equations of Volterra type with singular kernel,then we propose and analyze a spectral Jacobi-collocation approximation for nonlinear integro-differential equations of Volterra *** provide a rigorous error analysis for the spectral methods,which shows that both the errors of approximate solutions and the errors of approximate fractional derivatives of the solutions decay exponentially in L^(∞)-norm and weighted L^(2)-norm.

关键词： Spectral method nonlinear fractional derivative Volterra integro-differential equations Caputo derivative

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

阿尔茨海默病研究进展

临床心身疾病杂志 2024年第3期30卷 128-132页

作者：郭佳越汤燚杨银大理大学公共卫生学院云南大理671000 大理州第二人民医院云南大理671000

阿尔茨海默病(AD)是一种渐进性的神经退行性疾病,发病率逐年增高。然而针对AD经典发病机制研发的相关药物并未取得明显的治疗效果。近些年展开了众多关于AD发病机制、诊断及治疗的研究。本文综述了AD的病因、发病机制、临床表现和治疗方... 详细信息

阿尔茨海默病(AD)是一种渐进性的神经退行性疾病,发病率逐年增高。然而针对AD经典发病机制研发的相关药物并未取得明显的治疗效果。近些年展开了众多关于AD发病机制、诊断及治疗的研究。本文综述了AD的病因、发病机制、临床表现和治疗方法,以期为AD预防和治疗提供了新的策略。

关键词：阿尔茨海默病发病机制诊断治疗

Meeting the Demands of Socialist Core Values and Leading the People's Spiritual Needs

在线全文

学校读者我要写书评

暂无评论

学术界 2015年第10期 264-269页

作者： Wu yin yang Wei School of Marxism Beijing Jiaotong University Beijing 100044

The spiritual needs are uniquely human,which are the conditions of human existence and *** the process of socialist modernization construction in our country,the social economy develops rapidly and the material basis compacts *** people' s development is far *** socialist core values can lead people' s spiritual needs to be healthy and *** can also build the civic spiritual support system for social development,as well as help people establish the values and faiths that adapt to the socialist construction in our country.

关键词：社会主义现代化价值观社会主义建设人类生存物质基础社会经济支持系统社会发展

Shaped-Beam Pattern Synthesis Through the Construction of Weighted Generalized Rayleigh Quotient

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2019年第1期28卷 207-214页

作者： yang yin WAN Chuan SHENG Weixing HAN Yubing MA Xiaofeng School of Electronic and Optical Engineering Nanjing University of Science and Technology

A novel shaped-beam pattern synthesis method of generating an arbitrary footprint pattern under an arbitrary array structure is proposed. The embedded element pattern information is included in the pattern model, and a new cost function composed of three optimization items which are sidelobe levels,mainlobe ripples and mainlobe gains is constructed through the model. During the optimization process,to further enhance the performance of the synthesized pattern, a weight matrix is designed and added to the optimization items, then the generalized Rayleigh quotient approximation method is used to obtain the final array element excitations. To illustrate the good performance of the provided method, several synthesis examples with different arrays and footprints are presented. Compared with other algorithms such as Weighted alternating reverse projection(WARP) method, the proposed method can achieve better results with lower sidelobe levels, smaller mainlobe ripples and less computational load.

关键词： Pattern synthesis Embedded element pattern Mutual coupling Generalized Rayleigh quotient approximation Arbitrary footprint

Erroneous pixel prediction for semantic image segmentation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computational Visual Media 2022年第1期8卷 165-175页

作者： Lixue Gong Yiqun Zhang Yunke Zhang yin yang Weiwei Xu State Key Lab of CAD&CG Zhejiang UniversityHangzhou 310058China School of Computing Clemson University South Carolina29634USA

We consider semantic image *** method is inspired by Bayesian deep learning which improves image segmentation accuracy by modeling the uncertainty of the network *** contrast to uncertainty,our method directly learns to predict the erroneous pixels of a segmentation network,which is modeled as a binary classification *** can speed up training comparing to the Monte Carlo integration often used in Bayesian deep *** also allows us to train a branch to correct the labels of erroneous *** method consists of three stages:(i)predict pixel-wise error probability of the initial result,(ii)redetermine new labels for pixels with high error probability,and(iii)fuse the initial result and the redetermined result with respect to the error *** formulate the error-pixel prediction problem as a classification task and employ an error-prediction branch in the network to predict pixel-wise error *** also introduce a detail branch to focus the training process on the erroneous *** have experimentally validated our method on the Cityscapes and ADE20K *** model can be easily added to various advanced segmentation networks to improve their *** DeepLabv3+as an example,our network can achieve 82.88%of mloU on Cityscapes testing dataset and 45.73%on ADE20K validation dataset,improving corresponding DeepLabv3+results by 0.74%and 0.13%respectively.

关键词： erroneous pixel prediction image segmentation deep learning

Unsupervised image translation with distributional semantics awareness

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2023年第3期9卷 619-631页

作者： Zhexi Peng He Wang Yanlin Weng yin yang Tianjia Shao State Key Lab of CAD&CG Zhejiang UniversityHangzhou 310058China School of Computing University of LeedsLeedsUK School of Computing Clemson UniversityClemsonUSA

Unsupervised image translation(UIT)studies the mapping between two image *** such mappings are under-constrained,existing research has pursued various desirable properties such as distributional matching or two-way *** this paper,we re-examine UIT from a new perspective:distributional semantics consistency,based on the observation that data variations contain semantics,e.g.,shoes varying in ***,the semantics can be multi-dimensional,e.g.,shoes also varying in style,functionality,*** two image domains,matching these semantic dimensions during UIT will produce mappings with explicable correspondences,which has not been investigated *** propose distributional semantics mapping(DSM),the first UIT method which explicitly matches semantics between two *** show that distributional semantics has been rarely considered within and beyond UIT,even though it is a common problem in deep *** evaluate DSM on several benchmark datasets,demonstrating its general ability to capture distributional *** comparisons show that DSM not only produces explicable mappings,but also improves image quality in general.

关键词： generative adversarial networks(GANs) manifold alignment unsupervised learning image-to-image translation distributional semantics