检索结果-南通市图书馆

A novel micro-rolling&incremental sheet forming hybrid process:Deformation behavior and microstructure evolution

Chinese Journal of Aeronautics 2024年第5期37卷 603-622页

作者： yanle li Feifei liU Hao YUAN Xiaoqiang li Jianfeng li Guoqun ZHAO Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationShandong UniversityJi'nan 250061China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Key Laboratory for liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJi'nan 250061China

Thin-walled metal parts with functional micro-featured surface have broad application prospects in the fields of resistance reduction,noise reduction,*** this study,a novel micro-rolling&incremental sheet forming hybrid process(μR-ISF)is proposed to fabricate thin-walled metal parts with microgroove *** analytical model which relates the rolling force and microgroove depth in the micro-rolling stage was first ***,the formation mechanism of microgroove morphology during both micro-rolling stage and macro-shape forming stage are *** the micro-grooved sheet being incrementally formed,a significant reduction(between 21%to nearly 60%)is occurred in the depth of both transverse and longitudinal grooves compared to the flat ***,the width of transverse grooves decreases slightly by about 10%on average,while the width of longitudinal microgrooves increases significantly by more than 30%on *** micro-rolling,85°{102}tensile twins appear on the micro-grooved sheet and the percentage of 65°{112}compressive twins *** incremental forming,the percentage of low-angle grain boundaries and the density of geometrically necessary dislocations in the formed part increase significantly,and the grain size distribution becomes more *** present work provides a new strategy for the fabrication of 3D metal thin-walled components with surface micro-features.

关键词： Incremental sheet forming Microgrooves rolling Surface micromachining Groove size Microstructural evolution

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

热处理工艺对激光熔覆316L温度场与应力场的影响规律

引用

中国机械工程 2024年第4期35卷 666-677页

作者：李燕乐潘忠涛戚小霞崔维强陈健李方义山东大学机械工程学院高效洁净机械制造教育部重点实验室济南250061 中铁十四局集团有限公司济南250101

为研究不同热处理工艺对激光熔覆残余应力的调控作用,利用ANSYS有限元分析软件建立了热力耦合模型,对不同温度(22~900℃)的熔覆前预热处理、不同温度(200~1000℃)的熔覆后退火处理以及熔覆前后协同热处理条件下的激光熔覆316L不锈钢温... 详细信息

为研究不同热处理工艺对激光熔覆残余应力的调控作用,利用ANSYS有限元分析软件建立了热力耦合模型,对不同温度(22~900℃)的熔覆前预热处理、不同温度(200~1000℃)的熔覆后退火处理以及熔覆前后协同热处理条件下的激光熔覆316L不锈钢温度场和应力场进行了数值模拟。研究结果表明:预热对熔池温度影响最大,熔池温度随预热温度的增高而增高;退火处理对激光熔覆残余应力的改善效果最好,800℃退火处理可使残余应力减小约50%,其次是熔覆前后协同热处理,可使残余应力减小约35%,预热处理对激光熔覆残余应力有一定改善,其中预热500℃可使残余应力减小约20%。

关键词： 316L不锈钢激光熔覆热处理数值模拟残余应力

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

超声振动方向对激光定向能沉积Inconel 718性能影响研究

引用

表面技术 2024年第13期53卷 44-54页

作者：范伟光李燕乐牛家亭戚小霞潘忠涛李剑峰李方义山东大学机械工程学院济南250061 山东大学高效洁净机械制造教育部重点实验室济南250061

目的面向激光定向能沉积表面改性及再制造发展需求,揭示超声振动方向对激光定向能沉积Inconel 718零件的影响机制,为超声辅助激光定向能沉积高质量成形提供参考。方法开展多方向超声振动辅助激光定向能沉积Inconel 718零件试验,结合原... 详细信息

目的面向激光定向能沉积表面改性及再制造发展需求,揭示超声振动方向对激光定向能沉积Inconel 718零件的影响机制,为超声辅助激光定向能沉积高质量成形提供参考。方法开展多方向超声振动辅助激光定向能沉积Inconel 718零件试验,结合原位熔池监测技术,研究沉积方向、搭接方向和扫描方向超声振动对熔池流动行为、微观结构和力学性能的影响。结果不同方向超声振动显著影响了熔池的动态流动行为,其中搭接方向超声振动使熔池润湿面积提高了86.4%,并且形状更为规则,拖尾现象得到改善。微观组织细化方面,扫描方向振动效果最佳,晶体直径细化了46.9%,水平方向的晶体等轴晶转变优于沉积方向,而在沉积方向振动下,Laves相点球化和减少最为明显。相较于对照组的显微硬度210.4HV0.2,添加沉积、搭接和扫描方向超声振动后分别提高到了232.5HV0.2、230.9HV0.2和233.9HV0.2,变化趋势与晶体直径变化趋势基本一致。水平方向超声振动影响下,特别是扫描方向的超声振动在提高材料强度的同时,还在一定程度上保持了材料的延展性;在搭接方向上,超声振动辅助显示出较好的各向异性消除能力,获得了优异的硬度、强度和塑性匹配。结论不同方向超声振动,通过不同方向的惯性力和热流改善了熔池的动态流动性,其中搭接方向超声振动在扩大熔池润湿面积和改善熔池动态形状方面具有优异的综合能力。由于超声强度方向性传播衰减和引起不同的声压梯度,微观组织细化和Laves相的细小点球状消减分别在扫描方向和沉积方向上最为显著,这些变化引起了显微硬度和拉伸性能的相关性提升。超声振动还均衡了材料的力学性能,提高了抗拉强度、屈服强度和延展性,尤其在搭接方向上,显示出较好的各向异性消除能力。可根据具体需求目标,选用相应的超声振动方向或者复合使用,以获得优异的Inconel 718零件熔池流动、微观形貌和力学性能匹配。

关键词：激光定向能沉积 Inconel 718合金超声振动方向熔池流动微观结构力学性能

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

小肠转移性肿瘤的临床特点

引用

中华医学杂志 2024年第21期104卷 2003-2006页

作者：董旭旸李艳乐姚建宁张连峰郑州大学第一附属医院消化内科郑州

分析小肠转移性肿瘤的临床特点。回顾性分析郑州大学第一附属医院2018年1月1日至2022年12月31日收治的小肠转移性肿瘤患者的临床表现、影像学和内镜检查结果、治疗方法和随访情况。共纳入10例患者, 男7例, 女3例, 年龄33～77(56.4±12.6... 详细信息

分析小肠转移性肿瘤的临床特点。回顾性分析郑州大学第一附属医院2018年1月1日至2022年12月31日收治的小肠转移性肿瘤患者的临床表现、影像学和内镜检查结果、治疗方法和随访情况。共纳入10例患者, 男7例, 女3例, 年龄33～77(56.4±12.6)岁。主要临床表现为肠梗阻(腹痛、腹胀、恶心、呕吐、排气排便减少等症状, 8例), 部分患者出现肠套叠(腹痛、呕吐、黑便等症状, 1例)或消化道出血(1例), 早期症状隐匿。原发肿瘤包括胃癌(3例)、恶性黑色素瘤(2例)、卵巢癌(2例)、结肠癌(1例)、直肠癌(1例)及肺癌(1例)等, 多为低分化(6例)或中-低分化(2例)。原发肿瘤手术后距离发现小肠转移的中位时间[M(Q1, Q3)]为22(18, 28)个月。转移病灶可为单发(6例)或多发(4例);空肠及回肠均可出现。正电子发射计算机断层显像(PET-CT, 3例)及小肠镜检查(2例)有助于检出小肠转移。治疗方法以手术切除为主(9例), 辅以放疗、靶向药物、免疫治疗等。术后部分患者(5例)出现复发转移。患者多在确诊后4～29个月内死亡。小肠转移性肿瘤临床少见, 早期症状不典型, 常因出现肠梗阻等并发症而就诊, 易出现诊断延迟, 预后不良。

关键词：小肠转移性肿瘤临床特点肠梗阻

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

A toolpath strategy for improving geometric accuracy in double-sided incremental sheet forming

引用

Chinese Journal of Aeronautics 2023年第1期36卷 468-479页

作者： Sattar ULLAH Xiaoqiang li Peng XU yanle li Kai HAN Dongsheng li School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationSchool of Mechanical EngineeringShandong UniversityJinan 250061China

The double-sided incremental forming(DSIF)improved the process flexibility compared to other incremental sheet forming(ISF)*** the flexible nature,it faces the challenge of low geometric precision like ISF *** this work,two strategies are used to overcome ***,a novel method is employed to determine the optimal support tool location for improving geometric *** this method,the toolpath oriented the tools to each other systematically in the circumferential ***,it squeezed the sheet by the same amount at the point of *** impacts of various support tool positions in the circumferential direction are evaluated for geometric *** results demonstrate that the support tool should support the master tool within 10°to its local normal in the circumferential direction to improve the geometric ***,a two-stage process reduced the geometric error of the part by incrementally accommodating the springback error by artificially increasing the step size for the second *** the optimal support tool position and two-stage DSIF,the geometric precision of the part has improved *** proposed method is compared to the best DSIF toolpath strategies for geometric accuracy,surface roughness,forming time,and sheet thickness fluctuations using grey relational analysis(GRA).It outperforms the other toolpath strategies including single-stage DSIF,accumulative double-sided incremental forming(ADSIF),and two-stage mixed double sided incre-mental forming(MDSIF).Our approach can improve geometric precision in complex parts by successfully employing the support tool and managing the springback incrementally.

关键词： incremental sheet forming double-sided incremental forming geometric accuracy springback grey relational analyses

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

无痛胃肠镜下氩气刀切除术治疗胃肠息肉的效果

引用

中国实用医刊 2024年第15期51卷 38-41页

作者：牛倩倩李艳乐孙倩郑州大学第一附属医院消化内镜中心郑州郑州大学第一附属医院消化内科郑州

目的探讨无痛胃肠镜下氩气刀切除术治疗胃肠息肉的效果。方法队列研究。抽取2022年1月至2023年12月郑州大学第一附属医院收治的胃肠息肉患者62例, 按随机数字表法分为无痛组和常规组, 每组31例。无痛组采用无痛胃肠镜下氩气刀切除术, ... 详细信息

目的探讨无痛胃肠镜下氩气刀切除术治疗胃肠息肉的效果。方法队列研究。抽取2022年1月至2023年12月郑州大学第一附属医院收治的胃肠息肉患者62例, 按随机数字表法分为无痛组和常规组, 每组31例。无痛组采用无痛胃肠镜下氩气刀切除术, 常规组采用常规内镜下氩气刀切除术。比较两组围术期指标、术后视觉模拟评分法(VAS)评分、疼痛应激指标[C反应蛋白(CRP)、皮质醇(Cor)、前列腺素E2(PGE2)]水平及并发症发生率。结果无痛组手术操作时长、术后肠鸣音消失时间及术中出血量均少于对照组(P均<0.05)。术后3、6、12 h,无痛组VAS评分均低于常规组(P均<0.05);术后6 h, 无痛组CRP、Cor、PGE2水平低于常规组(P<0.05)。无痛组并发症发生率(3.23%, 1/31)低于常规组(25.81%, 8/31), P<0.05。结论无痛胃肠镜下氩气刀切除术用于胃肠息肉患者中可减少出血量, 缩短手术操作时长, 减轻机体疼痛和应激反应, 促进患者术后恢复, 且并发症较少, 安全性良好。

关键词：息肉无痛胃肠镜下氩气刀切除术疼痛程度

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

Formation mechanism and modeling of surface waviness in incremental sheet forming

引用

Frontiers of Mechanical Engineering 2022年第2期17卷 129-143页

作者： Kai HAN Xiaoqiang li yanle li Peng XU Yong li Qing li Dongsheng li School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China Beijing Institute of Aeronautical Materials Beijing 100095China School of Mechanical Engineering Shandong UniversityJinan 250061China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationJinan 250061China Materials Science Branch of Chinalco Research Institute Chinalco Materials Application Research Institute Co.Ltd.Beijing 102209China

mproving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of formation mechanism and control of surface quality in ISF.

关键词： surface waviness incremental sheet forming numerical simulation formation mechanism deformation history

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

Porous rod-like Ni_(2)P/Ni assemblies for enhanced urea electrooxidation

引用

Nano Research 2021年第5期14卷 1405-1412页

作者： Qing li Xinran li Jiawei Gu yanle li Ziqi Tian Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou225009China Guangling College Yangzhou UniversityYangzhou225009China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo315201China

The urea oxidation reaction has attracted increasing ***,porous rod-like Ni2P/Ni assemblies,which consist of numerous nanoparticle subunits with matching interfaces at the nanoscale have been synthesized via a simple phosphating *** functional theory calculations and density of states indicate that porous rod-like Ni2P/Ni assemblies can significantly enhance the activity of chemical bonds and the conductivity compared with NiO/Ni toward the urea oxidation *** optimal catalyst of Ni2P/Ni can deliver a low overpotential of 50 mV at 10 mA·cm−2 and Tafel slope of 87.6 mV·dec−1 in urea oxidation ***,the constructed electrolytic cell exhibits a current density of 10 mA·cm−2 at a cell voltage of 1.47 V and an outstanding durability in the two-electrode *** work has provided a new possibility to fabricate metal phosphides-metal assemblies with advanced performance.

关键词： rod-like Ni_(2)P/Ni electrocatalyst urea electrooxidation overall urea electrolysis

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

Experimental and numerical investigation on surface quality for two-point incremental sheet forming with interpolator

引用

Chinese Journal of Aeronautics 2020年第10期33卷 2794-2806页

作者： Xiaoqiang li Kai HAN Xu SONG Haibo WANG Dongsheng li yanle li Qing li School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationSchool of Mechanical EngineeringShandong UniversityJinan 250061China Materials Science Branch of Chinalco Research Institute Chinalco Materials Application Research Institute Co.LTDBeijing 102209China

The unsatisfied surface quality seriously impedes the wide application of incremental sheet forming(ISF)in industrial *** a novel approach,the interpolator method is a promising strategy to enhance the surface quality in ***,the mechanism for the improvement of surface quality and the influence of interpolator properties on surface roughness are not well *** this paper,the influences of process variables(*** diameter,step size and thickness of interpolators)on the forming process(*** roughness,forming force and geometric error)are investigated through a systematic experimental approach of central composite design(CCD)in two-point incremental sheet forming(TPIF).It is obtained that the increase in thickness of interpolators decreases the surface roughness in direction vertical to the tool path while increases the surface roughness in direction horizontal to the tool ***,the combined influence between thickness of interpolators and process parameters(tool diameter and step size)is ***,the placement of interpolator has little influence on the effective forming force of *** addition,the geometric error enlarges with the increase of step size and thickness of interpolator while decreases firstly and then increase with an increase in tool ***,the influencing mechanism of the interpolator method on surface quality can be attributed to the decrease of thecontact pressure due to the increase of contact area with the unchanged contact ***,the interpolator method eliminates the sliding friction on the surface of blank due to the stable relative position between the blank and the interpolator.

关键词： Forming force Geometric error Interpolator Process parameter Surface quality Two-point incremental sheet forming

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

ZmCYP90D1 regulates maize internode development by modulating brassinosteroid-mediated cell division and growth

引用

The Crop Journal 2024年第1期12卷 58-67页

作者： Canran Sun Yang liu Guofang li yanle Chen Mengyuan li Ruihua Yang Yongtian Qin Yongqiang Chen Jinpeng Cheng Jihua Tang Zhiyuan Fu Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy Henan Agricultural UniversityZhengzhou 450046HenanChina The Shennong Laboratory Zhengzhou 450002HenanChina Hebi Academy of Agricultural Sciences Hebi 458030HenanChina Yunnan Tang Jihua Expert Workstation/Zhaotong Academy of Agricultural Sciences Zhaotong 657000YunnanChina

Plant height(PH)is associated with lodging resistance and planting density,which is regulated by a complicated gene *** this study,we identified a spontaneous dwarfing mutation in maize,m30,with decreased internode number and length but increased internode diameter.A candidate gene,ZmCYP90D1,which encodes a member of the cytochrome P450 family,was isolated by map-based ***90D1 was constitutively expressed and showed highest expression in basal internodes,and its protein was targeted to the nucleus.A G-to-A substitution was identified to be the causal mutation,which resulted in a truncated protein in *** of function of ZmCYP90D1 changed expression of hormoneresponsive genes,in particular brassinosteroid(BR)-responsive genes which is mainly involved in cell cycle regulation and cell wall extension and modification in *** concentration of typhasterol(TY),a downstream intermediate of ZmCYP90D1 in the BR pathway,was reduced.A haplotype conferring dwarfing without reducing yield was ***90D1 was inferred to influence plant height and stalk diameter via hormone-mediated cell division and cell growth via the BR pathway.

关键词： Maize ZmCYP90D1 BR biosynthesis Dwarf plant

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：