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Effects of Loading Paths on Hydrodynamic Deep Drawing with Independent Radial Hydraulic Pressure of Aluminum Alloy Based on Numerical Simulation

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Journal of Materials Science & Technology 2008年第3期24卷 395-399页

作者： Xiaojing LIU yongchao xu Shijian YUAN School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China College of Materials Science and Engineering Harbin University of Science and Technology Harbin 150040 China

In order to meet the forming demands for low plasticity materials and large height-diameter ratio parts, a new process of hydrodynamic deep drawing （HDD） with independent radial hydraulic pressure is proposed. To investigate the effects of loading paths on the HDD with independent radial hydraulic pressure, the forming process of 5A06 aluminum alloy cylindrical cup with a hemispherical bottom was studied by numerical simulation. By employing the dynamic explicit analytical software ETA/Dynaform based on LS-DYNA3D, the effects of loading paths on the sheet-thickness distribution and surface quality were analyzed. The corresponding relations of the radial hydraulic pressure loading paths and the part＇s strain status on the forming limit diagram （FLD） were also discussed. The results indicated that a sound match between liquid chamber pressure and independent radial hydraulic pressure could restrain the serious thinning at the hemisphere bottom and that through adjusting radial hydraulic pressure could reduce the radial tensile strain and change the strain paths. Therefore, the drawing limit of the aluminum cylindrical cup with a hemispherical bottom could be increased significantly.

关键词： Hydrodynamic deep drawing Numerical simulation Independent radial hydraulic pressure 5A06 aluminum alloy

Feature context learning for human parsing

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Science China(Information Sciences) 2019年第12期62卷 6-19页

作者： Tengteng HUANG yongchao xu Song BAI Yongpan WANG Xiang BAI School of Electronic Information and Communications Huazhong University of Science and Technology Alibaba Group

Parsing inconsistency, referring to the scatters and speckles in the parsing results as well as imprecise contours, is a long-standing problem in human parsing. It results from the fact that the pixel-wise classification loss independently considers each pixel. To address the inconsistency issue, we propose in this paper an end-to-end trainable, highly flexible and generic module called feature context module(FCM).FCM explores the correlation of adjacent pixels and aggregates the contextual information embedded in the real topology of the human body. Therefore, the feature representations are enhanced and thus quite robust in distinguishing semantically related parts. Extensive experiments are done with three different backbone models and four benchmark datasets, suggesting that FCM can be an effective and efficient plug-in to consistently improve the performance of existing algorithms without sacrificing the inference speed too much.

关键词： human parsing context learning fully convolutional networks graph convolutional network semantic segmentation

Investigation on the Formability of 5A06 Sheet for Rapid Gas Forming

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稀有金属材料与工程 2011年第S3期40卷 144-147页

作者： He Zhubin, Fan Xiaobo, xu yongchao, Yuan Shijian Harbin Institute of Technology, Harbin 150001, China Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The formability of light-weight alloy, such as aluminum alloy, magnesium alloy, can be improved significantly when formed at elevated temperature. Superplastic forming (SPF) is a well-known manufacturing method to form complex part of these materials. In order to realize mass production of SPF in industry, forming at high strain rate should be realized. In this study, the mechanical properties of 5A06 sheet were tested by uniaxial tensile test at high strain rate and elevated temperatures up to 550 ℃. Free bulging test and forming of round cup were carried out to evaluate the formability of the 5A06 sheet. Results show that the total elongation of the 5A06 sheet began to increase rapidly after 200 ℃, and reached the maximum value at 450 ℃. At higher temperature, early brittle fracture occurred. In free bulging test, the bulging height remained almost constant about 27.0 mm, which means the formability of the sheet is not sensitive to forming temperature at elevated temperature. In the forming of round cup part, temperature has direct effect on the corner filling ability of the sheet, especially at temperature lower than 400 ℃.

关键词： 5A06 sheet formability superplastic forming (SPF) rapid gas forming (RGF) free bulging test

Molecular mechanisms of adaptive evolution in wild animals and plants

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Science China(Life Sciences) 2023年第3期66卷 453-495页

作者： Yibo Hu Xiaoping Wang yongchao xu Hui Yang Zeyu Tong Ran Tian Shaohua xu Li Yu Yalong Guo Peng Shi Shuangquan Huang Guang Yang Suhua Shi Fuwen Wei CAS Key Lab of Animal Ecology and Conservation Biology Chinese Academy of SciencesBeijing 100101China State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan School of Life SciencesYunnan UniversityKunming 650091China State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of SciencesBeijing 100093China State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of SciencesKunming 650201China Institute of Evolution and Ecology School of Life SciencesCentral China Normal UniversityWuhan 430079China College of Life Sciences Nanjing Normal UniversityNanjing 210023China State Key Laboratory of Biocontrol Guangdong Key Lab of Plant ResourcesSchool of Life SciencesSun Yat-sen University Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China

Wild animals and plants have developed a variety of adaptive traits driven by adaptive evolution,an important strategy for species survival and *** the molecular mechanisms of adaptive evolution is the key to understanding species diversification,phenotypic convergence,and inter-species *** the genome sequences of more and more non-model organisms are becoming available,the focus of studies on molecular mechanisms of adaptive evolution has shifted from the candidate gene method to genetic mapping based on genome-wide *** this study,we reviewed the latest research advances in wild animals and plants,focusing on adaptive traits,convergent evolution,and ***,we focused on the adaptive evolution of morphological,behavioral,and physiological ***,we reviewed the phenotypic convergences of life history traits and responding to environmental pressures,and the underlying molecular convergence ***,we summarized the advances of coevolution,including the four main types:mutualism,parasitism,predation and ***,these latest advances greatly increase our understanding of the underlying molecular mechanisms for diverse adaptive traits and species interaction,demonstrating that the development of evolutionary biology has been greatly accelerated by multi-omics ***,we highlighted the emerging trends and future prospects around the above three aspects of adaptive evolution.

关键词： adaptive evolution adaptive trait coevolution comparative genomics convergent evolution genetic convergence molecular mechanism mutualism parasitism phenotype convergence

Investigation of SUS304 Stainless Steel with Warm Hydro-mechanical Deep Drawing

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Journal of Materials Science & Technology 2004年第1期20卷 92-93页

作者： yongchao xu, Dachang KANG and Shihong ZHANGSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaShihong ZHANGInstitute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China Sch. of Mat. Sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Basing on warm mechanical property of SUS304 stainless steel and hydro-mechanical deep drawing process, warm hydro-mechanical deep drawing process is proposed and discussed with experiments in this paper. The experiments are performed at four different temperatures. The results show that the formability of stainless steel is improved under the condition of warm temperature. Warm hydro-mechanical deep drawing raises limiting drawing ratio of SUS304 effectively, and limiting drawing ratio 3.3 is obtained, which is beyond 2.0 with conventional deep drawing. The temperature of 90℃ is beneficial to the forming of SUS304 stainless steel, the strain-induced martensite is controlled effectively, and the thickness distribution is more uniform.

关键词： SUS304 stainless steel Warm hydro-mechanical deep drawing Forming Cylindrical cup

一种断层面约束下的Delaunay三角剖分与等值线生成算法

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中国石油大学学报（自然科学版） 2023年第6期47卷 35-42页

作者：宋建国许永超中国石油大学(华东)地球科学与技术学院山东青岛266580

传统等值线算法在生成等值线图时,往往采用先生成等值线后抠除断层多边形的方法,或者采用先抠除断层多边形再直接生成等值线的方法。这两种方法均忽略了断层处的层位信息,因而在断层面附近的精度达不到现代油气资源勘探的要求。对断层... 详细信息

传统等值线算法在生成等值线图时,往往采用先生成等值线后抠除断层多边形的方法,或者采用先抠除断层多边形再直接生成等值线的方法。这两种方法均忽略了断层处的层位信息,因而在断层面附近的精度达不到现代油气资源勘探的要求。对断层面与解释层位交点进行精细处理,通过对断层数据的细分加密得到断层面的精确控制点序列,使用Clough-Tocher插值方法进行插值,获得断层面处层位点的高程,提高等值线在断层面处的精度。研究断层面约束的Delaunay三角剖分,设计光滑等值线快速生成算法。形成断层面约束下的层位等值线自动生成技术模块。结果表明,该方法不仅提高等值线绘制的精度,同时也有效降低等值线查找的复杂度,提高了计算效率。

关键词：断层面约束 Delaunay三角剖分 α-shape算法等值线高精度插值

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媒体融合背景下高校数字图书馆发展影响因素研究

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图书情报工作 2017年第3期61卷 29-38页

作者：薛调续永超天津理工大学图书馆天津300384

[目的 /意义]在媒体融合背景下,以传播学中的"使用与满足理论"以及相关研究为基础,从用户角度对高校数字图书馆发展的影响因素进行分析,并对数字图书馆建设提出建议。[方法/过程]采取访谈法对高校图书馆主管馆长和部主任进行访谈,从而... 详细信息

[目的 /意义]在媒体融合背景下,以传播学中的"使用与满足理论"以及相关研究为基础,从用户角度对高校数字图书馆发展的影响因素进行分析,并对数字图书馆建设提出建议。[方法/过程]采取访谈法对高校图书馆主管馆长和部主任进行访谈,从而获取数据,提取影响数字图书馆发展的相关因素,根据提取结果设计调查问卷,并进行数据收集。利用SPSS软件进行因子分析、相关分析、回归分析。[结果 /结论]研究发现,"馆员能力与素养"对高校数字图书馆发展的影响最大,"空间服务""服务需求程度"次之,"设备设施服务""新媒体服务""资源建设"再次之。构建高校数字图书馆发展影响因素的"6340模型"。在馆员队伍建设、空间构建与再造、服务模式体系构建、设备设施建设和资源建设5个方面提出建议。

关键词：数字图书馆高校图书馆使用与满足理论因子分析回归分析

关于本原射影Reed-Solomon码的深洞

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中国科学：数学 2018年第8期48卷 1087-1094页

作者：徐小凡洪绍方许永超四川大学数学学院成都610064

本原射影Reed-Solomon码是数字通信领域中的一类重要的极大距离可分码.在本原射影ReedSolomon码的译码过程中,人们通常采用极大似然译码算法.对于一个收到的向量u∈F_q^n,极大似然译码算法关键在于确定向量u关于码C的错误距离d(u,C).熟... 详细信息

本原射影Reed-Solomon码是数字通信领域中的一类重要的极大距离可分码.在本原射影ReedSolomon码的译码过程中,人们通常采用极大似然译码算法.对于一个收到的向量u∈F_q^n,极大似然译码算法关键在于确定向量u关于码C的错误距离d(u,C).熟知d(u,C)≤ρ(C),其中ρ(C)为码C的覆盖半径.若d(u,C)=ρ(C),则称u为码C的深洞.本文得到了本原射影Reed-Solomon码PPRS_q(F_q~*,k)的一类深洞.实际上,利用有限域F_q上极大距离可分码的生成矩阵,本文证明如下结果成立:如果q≥4,整数k满足2≤k≤q-2,收到的向量u的前q-1个分量的Lagrange插值多项式为u(x)=λx^(q-2)+f≤k-2(x),其中λ∈F_q~*,f≤k-2(x)为F_q上次数不超过k-2的多项式,并且u的第q个分量为0,那么u是本原射影Reed-Solomon码PPRSq(F_q~*,k)的一个深洞.

关键词：本原射影Reed-Solomon码 MDS(maximum distance separable)码深洞

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安全阀排放的动响应分析

化工设备与管道 2024年第2期61卷 28-32页

作者：许永超李楠中国石油化工股份有限公司工程部北京100728

安全阀排放冲击与响应是振动工程中典型的瞬态响应问题。根据阀后直管段长度L与特征长*度L的关系,讨论了四种可能的冲击形式;利用Laplace变换和逆变换,给出了四种冲击的瞬态响应解析解,表明冲击响应的最大幅值是关于安全阀全开时间与系... 详细信息

安全阀排放冲击与响应是振动工程中典型的瞬态响应问题。根据阀后直管段长度L与特征长*度L的关系,讨论了四种可能的冲击形式;利用Laplace变换和逆变换,给出了四种冲击的瞬态响应解析解,表明冲击响应的最大幅值是关于安全阀全开时间与系统自振周期之比的函数;据此对安全阀排放系统的动载系数DFL取值给了分析和建议。

关键词：安全阀瞬态响应脉冲拉普拉斯变换响应解析解动载系数DFL