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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

Towards human-leveled vision systems

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Science China Technological Sciences 2024年

作者： DING JianHao HUANG tiejun State Key Laboratory of Multimedia Information Processing School of Computer Science Peking University

The human visual system is a complex and interconnected network comprising billions of neurons. It plays an essential role in translating environmental light stimuli into information that guides and shapes human perception and action. Research on the visual system aims to uncover the underlying neural structure principles of human visual perception and their possible applications.Currently, there are two main approaches: biological system analysis and simulation, artificial intelligence models based on deep learning. Here we aim to discuss the two approaches to human-level vision systems. Deep learning has significantly impacted the field of vision with achievements in representation, modeling, and hardware design. However, there is still a significant gap between deep learning models and the human visual system in terms of scalability, transferability, and sustainability. The progress of the biological visual system can help fill the gap by further understanding the properties and functions of different components of the system. We take the efforts of reconstructing the retina as an example to illustrate that even if we are unable to replicate the visual system on a computer right now, we can still learn a lot by combining existing research outcomes in neuroscience. At the end of the paper, we suggest tracing back to gradually build visual systems from the computational counterpart of biological structures to achieve a human-level vision system in the future.

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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

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

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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基于改进YOLOv5的路面病害检测模型

土木工程学报 2024年第2期57卷 96-106页

作者：何铁军李华恩东南大学智能运输系统研究中心江苏南京211189

为进一步提高路面病害检测精度,文章在YOLOv5的基础上,提出针对路面病害特征改进的检测模型Pavement Damage-YOLO(PD-YOLO)。PD-YOLO在网络结构中引入Space-to-depth层,以适应低分辨率和路面病害目标小的检测任务。此外,模型在池化层利... 详细信息

为进一步提高路面病害检测精度,文章在YOLOv5的基础上,提出针对路面病害特征改进的检测模型Pavement Damage-YOLO(PD-YOLO)。PD-YOLO在网络结构中引入Space-to-depth层,以适应低分辨率和路面病害目标小的检测任务。此外,模型在池化层利用SPPFCSPC,在特征提取时获取不同的感受野,有效解决路面病害检测图像中目标大小差异较大的情况;在特征融合层引入ASFF模块使模型自适应学习不同特征间的联系,加强模型对病害目标区域的关注度。在对多组测试数据集测试中,与YOLOv5相比,PD-YOLO模型同时提高了检测结果的准确率、召回率、F1值以及mAP@0.5值,证明了PD-YOLO有着更强的特征提取能力和特征融合能力,在路面病害的检测上有更优越的表现。

关键词： PD-YOLO 路面病害目标检测深度学习 SPD模块

部族、地理、家园:近代东北概念生成的政治文化空间

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社会科学战线 2024年第5期 140-148页

作者：王铁军辽宁大学历史学部辽宁沈阳110122

文章旨在探讨从“满洲”到“东三省”,再到“东北”地理概念生成过程中的政治文化空间问题。起初,“满洲”一词只是作为部族的名称被固定,尤其是在满族入主中原后的相当长的一段时期里,“满洲”作为区分其他族群,彰显统治阶层种种特权... 详细信息

文章旨在探讨从“满洲”到“东三省”,再到“东北”地理概念生成过程中的政治文化空间问题。起初,“满洲”一词只是作为部族的名称被固定,尤其是在满族入主中原后的相当长的一段时期里,“满洲”作为区分其他族群,彰显统治阶层种种特权的代名词。在“满洲”作为地理名称之后,随着1907年清末东北新政奉、吉、黑三个行省的出现,“东三省”不仅作为政制的名称,也成为取代“满洲”的地理名称。“东北”一词先是出现在1928年“东北易帜”之后的官方文件中,在作为地理名称普及后,“东北”被赋予更多的时代含义,成为十四年抗战中,东北民众与关内民众一起团结一致、坚持抗战、收复故土的精神图腾。

关键词： “满洲” 东三省东北概念生成空间

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

Uroflowmetry is an uroflow measurement technique used to record the voided volume (VV) and flow rate, which can help clinicians objectively evaluate lower urinary tract function. Currently, few uroflowmetry studies have focused on the female population, especially on the uroflow curve standard analysis. Hence, we sought to establish dependable uroflow reference values and nomograms for Chinese women and to evaluate the relationship between uroflow patterns and demographic data.

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