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Multi-scale analyses of phase transformation mechanisms and hardness in linear friction welded Ti17(a+β)/Ti17(β)dissimilar titanium alloy joint

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Chinese Journal of Aeronautics 2024年第1期37卷 312-324页

作者： Zhenguo GUO tiejun MA Xiawei YANG Ju LI Wenya LI Achilles VAIRIS State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China Aeronautical Key Laboratory for Welding and Joining Technologies AVIC Manufacturing Technology InstituteBeijing 100024China Mechanical Engineering Department University of West AtticaAthens 12241Greece

The Ti17(a+β)-Ti17(β)dual alloy-dual property blisk produced using Linear Friction Welding(LFW)is considered as high-performance component in advanced aeroengine.However,up to now,microstructure evolution and relationship between microstructure and micro mechanical properties of LFWed Ti17(a+β)/Ti17(β)dissimilar joint have not been thoroughly revealed.In this work,complex analyses of the phase transformation mechanisms of the joint are conducted,and phase transformations in individual zones are correlated to their microhardness and nanohardness.Results reveal that a dissolution occurs under high temperatures encountered during LFW,which reduces microhardness of the joint to that of Ti17(a+β)and Ti17(β).In ThermoMechanically Affected Zone of Ti17(a+β)(TMAZ-(a+β))side joint,a large number of nanocrystalline a phases form with different orientations.This microstructure strengthens significantly by fine grains which balances partial softening effect of a dissolution,and increases nanohardness of a phase and microhardness of TMAZ-(a+β).Superlattice metastableβphase precipitates from metastableβin Weld Zone(WZ)during quick cooling following welding,because of short-range diffusion migration of solute atoms,especiallyβstabilizing elements Mo and Cr.The precipitation of the superlattice metastableβphase results in precipitation strengthening,which in turn increases nanohardness of metastableβand microhardness in WZ.

关键词： Linear friction welding Ti17 titanium alloy Phase transformation Microhardness Nanohardness

Zinc lactate alleviates oxidative stress by modulating crosstalk between constitutive androstane receptor signaling pathway and gut microbiota profile in weaned piglets

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Animal Nutrition 2024年第1期16卷 23-33页

作者： Wenjie Tang Xuan Xiang Houfu Wang Wentao Zhou liuqin He Yulong Yin tiejun Li College of Animal Science and Technology Hunan Agricultural University Sichuan Academy of Animal Sciences Animal Breeding and Genetics Key Laboratory of Sichuan Province Livestock and Poultry Biological Products Key Laboratory of Sichuan Province Sichuan Animtech Feed Co. Ltd Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process CAS Key Laboratory of Agro-Ecological Processes in Subtropical Region National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production Institute of Subtropical Agriculture Chinese Academy of Sciences College of Advanced Agricultural Science University of Chinese Academy of Sciences Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation Laboratory of Animal Nutrition and Human Health College of Life Sciences Hunan Normal University

This study aimed to determine the regulatory mechanism of dietary zinc lactate (ZL) supplementation on intestinal oxidative stress damage in a paraquat (PQ)-induced piglet model. Twenty-eight piglets (mean body weight 9.51±0.23 kg) weaned at 28 d of age were randomly divided into control, ZL, PQ, and ZL+PQ groups (n=7 in each group). The ZL-supplemented diet had little effect on growth performance under normal physiological conditions. However, under PQ challenge, ZL supplementation significantly improved average daily gain (P<0.05) and reduced the frequency of diarrhea. ZL improved intestinal morphology and ultrastructure by significantly increasing the expression level of the jejunal tight junction protein, zonula occludens-1(ZO-1) (P<0.05), and intestinal zinc transport and absorption in PQ-induced piglets, which reduced intestinal permeability. ZL supplementation also enhanced the expression of antioxidant and antiinflammatory factor-related genes and decreased inflammatory cytokine expression and secretion in PQinduced piglets. Furthermore, ZL treatment significantly inhibited the activation of constitutive androstane receptor (CAR) signaling (P<0.01) in PQ-induced piglets and altered the structure of the gut microbiota, especially by significantly increasing the abundance of beneficial gut microbes, including UCG＿002, Ruminococcus, Rikenellaceae＿RC9＿gut＿group, Christensenellaceae＿R＿7＿group, Treponema, unclassified＿Christensenellaceae, and unclassified＿Erysipelotrichaceae (P <0.05). These data reveal that pre-administration of ZL to piglets can suppress intestinal oxidative stress by improving antioxidant and anti-inflammatory capacity and regulating the crosstalk between CAR signaling and gut microbiota.

关键词： Zinc lactate Intestinal barrier Oxidative stress Inflammation Constitutive androstane receptor Gut microbiota

A review of linear friction welding of Ni -based superalloys

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1382-1391页

作者： Xiawei Yang Tingxi Meng Qiang Chu Yu Su Zhenguo Guo Rui Xu Wenlong Fan tiejun Ma Wenya Li State Key Laboratory of Solidification Processing Shaanxi Key Laboratory of Friction Welding TechnologiesNorthwestern Polytechnical UniversityXi’an 710072China Xi’an Aerospace Engine Co.Ltd. Xi’an 710100China

Ni-based superalloys are one of the most important materials employed in high-temperature applications within the aerospace and nuclear energy industries and in gas turbines due to their excellent corrosion,radiation,fatigue resistance,and high-temperature strength.Linear friction welding(LFW)is a new joining technology with near-net-forming characteristics that can be used for the manu-facture and repair of a wide range of aerospace components.This paper reviews published works on LFW of Ni-based superalloys with the aim of understanding the characteristics of frictional heat generation and extrusion deformation,microstructures,mechanical proper-ties,flash morphology,residual stresses,creep,and fatigue of Ni-based superalloy weldments produced with LFW to enable future optim-um utilization of the LFW process.

关键词： Ni-based superalloys linear friction welding microstructures mechanical properties flash morphology

A multicenter uroflowmetry study of healthy women in China

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中华医学杂志(英文版) 2024年第10期137卷 1225-1227页

作者： liu Xiaodong Meng Lingfeng Wang Jiawen Ma Tianming Shi Benkang Huang Hai Wang Qingwei Chen Min Liao Limin Shen Hong Wei Zhongqing Xiao Yuansong Pan tiejun Ren Jian Zhang Peng Tian Xiaojun Zhang Yaoguang Department of Urology The Second Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu China Department of Urology General Hospital of Southern Theatre Command Guangzhou Guangdong China Department of Urology General Hospital of Central Theatre Command Wuhan Hubei China Department of Urology China-Japan Friendship Hospital Beijing China Department of Urology Beijing Chao-Yang Hospital Beijing China Department of Urology Peking University Third Hospital Beijing China Department of Urology Beijing Hospital National Center of Gerontology Institute of Geriatric Medicine Chinese Academy of Medical Sciences &amp Peking Union Medical College Beijing China Graduate School of Peking Union Medical College Beijing China Department of Urology Qilu Hospital Shandong University Jinan Shandong China Department of Urology SUN YAT-SEN Memorial Hospital Guangzhou Guangdong China Department of Urology The First Affiliated Hospital of Zhengzhou University Zhengzhou Henan China Department of Urology Tongji Hospital Tongji Medical College of Huazhong University of Science and Technology Wuhan Hubei China Department of Urology China Rehabilitation Research Center Beijing China Department of Urology West China Hospital Chengdu Sichuan China

基于生物脉冲信号的视觉神经编码验证方法研究

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电子与信息学报 2024年第1期46卷 317-326页

作者：张燚钧刘健黄铁军中移(苏州)软件技术有限公司PaaS产品部苏州215004 利兹大学计算学院利兹LS29JT 北京大学计算机学院北京100190

研究界对如何对神经编码模型的性能度量还没有达成一个统一的评价标准。现有的主要编码度量方法是对神经编码模型的编码响应与真实生理响应之间的相似度进行度量。该文提出一种通过神经解码验证神经编码模型性能的方法。基于此方法构建... 详细信息

研究界对如何对神经编码模型的性能度量还没有达成一个统一的评价标准。现有的主要编码度量方法是对神经编码模型的编码响应与真实生理响应之间的相似度进行度量。该文提出一种通过神经解码验证神经编码模型性能的方法。基于此方法构建了包括传统编码度量方法和神经解码度量方法的视觉脉冲信号编码验证框架,并基于动态视觉刺激下采集的蝾螈视网膜神经节细胞(RGC)脉冲信号数据集对此框架进行了实验验证。选择了具有动态视觉刺激脉冲响应编码能力的编码模型与性能先进的神经解码模型作为标准度量模型。实验从不同神经编码方式和不同维度全面地对3种神经编码模型的编码性能进行了度量。此外,实验结果表明,脉冲频率编码和脉冲计数编码两种编码方式对脉冲编码性能存在不可忽略的影响。

关键词：神经编码神经解码视觉系统类脑视觉

CD97 inhibits osteoclast differentiation via Rap1a/ERK pathway under compression

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International Journal of Oral Science 2024年第1期16卷 134-144页

作者： Xuan Zhou Xinjia Cai Fengyang Jing Xuefen Li Jianyun Zhang Heyu Zhang tiejun Li Department of Oral Pathology Peking University School and Hospital of Stomatology&National Center of Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Laboratory for Digital and Material Technology of Stomatology&Beijing Key Laboratory of Digital Stomatology&Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health&NMPA Key Laboratory for Dental MaterialsBeijingChina Research Unit of Precision Pathologic Diagnosis in Tumors of the Oral and Maxillofacial Regions Chinese Academy of Medical Sciences(2019RU034)BeijingChina Central Laboratory Peking University School and Hospital of StomatologyBeijingChina

Acceleration of tooth movement during orthodontic treatment is challenging, with osteoclast-mediated bone resorption on the compressive side being the rate-limiting step. Recent studies have demonstrated that mechanoreceptors on the surface of monocytes/macrophages, especially adhesion G protein-coupled receptors (aGPCRs), play important roles in force sensing.However, its role in the regulation of osteoclast differentiation remains unclear. Herein, through single-cell analysis, we revealed that CD97, a novel mechanosensitive aGPCR, was expressed in macrophages. Compression upregulated CD97 expression and inhibited osteoclast differentiation;while knockdown of CD97 partially rescued osteoclast differentiation. It suggests that CD97 may be an important mechanosensitive receptor during osteoclast differentiation. RNA sequencing analysis showed that the Rap1a/ERK signalling pathway mediates the effects of CD97 on osteoclast differentiation under compression. Consistently, we clarified that administration of the Rap1a inhibitor GGTI298 increased osteoclast activity, thereby accelerating tooth movement. In conclusion,our results indicate that CD97 suppresses osteoclast differentiation through the Rap1a/ERK signalling pathway under orthodontic compressive force.

关键词： CD97 osteoclast inhibited

Geometrical　Modeling　by　NURBS　Surface　and　RCS　Computing　by　Visualization　for　Complex　Targets

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Journal of Systems Engineering and Electronics 1997年第1期8卷 13-21页

作者： Zhou, Yong liu, tiejun Beijing Inst of Environmental Features Beijing China

A novel approach to compute the high frequency radar cross-section (RCS) of complex targets is described in this paper.From the three views or the sectional views of the target, target is geometrically modeled by non-uniform rational B-spline (NURBS) parametric surfaces using the software CNFEOV developed by oneself which constructs NURBS representation of complex target from engineering orthographic views. RCS is obtained through PO, PTD, MEC and IBC techniques. When calculating RCS of the target, it is necessary to get the unit normal vector to surface illumi- nated by radar and the value Z which is the distance from the point on the surface to radar. ln this novel approach, the unit normal vector to the surface can be obtained either by the Phong rendering model, in which the color components (RGB) of every pixel on the image are equal to the coordinate components of the normal, or by the NURBS expressions. The value Z can be achieved by software or hardware Z-buffer. The effects of the size of image on the RCS of target are discussed and the correct method is recommended. The RCS of the perfect conducting sphere, cylinder and dihedral as well as the coated cylinder, as some examples, are computed. The accuracy of the method is verified by comparing the numerical results with those obtained by using other methods.

关键词： RCS Visualization computation Geometrical modeling.

导电压头作用下的功能梯度压电涂层二维黏附接触问题研究

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应用数学和力学 2024年第2期45卷 227-244页

作者：韩立夫刘铁军内蒙古工业大学理学院呼和浩特010051 河套学院内蒙古巴彦淖尔015000

纳米压痕实验是研究材料的力学性能和表面形貌的重要手段,当接触区尺寸减小时,压头与试件接触表面间的黏附作用将无法忽视,因此,考虑黏附作用对压头作用下的接触问题具有重要的价值.功能梯度压电材料(FGPM)兼具梯度材料和压电材料的优点... 详细信息

纳米压痕实验是研究材料的力学性能和表面形貌的重要手段,当接触区尺寸减小时,压头与试件接触表面间的黏附作用将无法忽视,因此,考虑黏附作用对压头作用下的接触问题具有重要的价值.功能梯度压电材料(FGPM)兼具梯度材料和压电材料的优点,用作涂层可有效地抑制接触损伤和破坏.该文将针对梯度压电材料在导电压头作用下的黏附接触问题开展研究,假设功能梯度压电涂层的材料参数按照指数形式变化,基于Maugis黏附模型,利用Fourier积分变换获得了功能梯度压电涂层在导电压头作用下的二维无摩擦黏附接触问题的控制奇异积分方程,并采用Erdogan-Gupta的数值方法求解,获得了黏附应力、梯度参数和压头所带电荷对力-电耦合响应的影响.研究结果为利用功能梯度压电材料涂层改善材料表面的接触行为提供了理论依据,同时可为压电结构及器件的设计提供帮助.

关键词：功能梯度压电涂层黏附 Fourier积分变换奇异积分方程

A dual-band wireless communication of spoof plasmonic meta-waveguide

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Science China(Information Sciences) 2024年第7期67卷 337-338页

作者： Xinxin GAO Geng-Bo WU Ze GU Qian MA Wenyi CUI tiejun CUI Chihou CHAN State Key Laboratory of Terahertz and Millimeter Waves City University of Hong Kong State Key Laboratory of Millimeter Waves Southeast University Department of Electrical Engineering City University of Hong Kong

The ever-growing demands in wireless communications,computational imaging, and light detection necessitate the capability to freely manipulate electromagnetic waves.Miniaturized and highly integrated devices hold great promise for the future of communications. Spoof plasmonic metamaterials, in particular, have shown potential in creating functional devices and systems due to their ultracompact and low-profile advantages [1–3].

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