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Thermal Stress and Assembling Parameters Evolution of CMC Bolted Joint under Transient Thermal Loads

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Journal of Harbin Institute of Technology(New Series) 2021年第3期28卷 1-8页

作者： Shuyuan Zhao Zhengyu Li Zeliang Pu Xinyang Sun wenjiao zhang National Key Laboratory of Science and Technology for National Defense on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China School of Aeronautics and Astronautics Harbin Institute of TechnologyHarbin 150001China Engineering College Northeast Agricultural UniversityHarbin 150030China

Ceramic matrix composite(CMC) and superalloy bolted joints have exhibited great potential for high temperature hot structure application in hypersonic aircraft. In service conditions, the thermal expansion mismatch between CMC and superalloy plates will cause complex thermal stress and strain distributions at hole-edge areas and assembly parameters changes of the joints under elevated temperatures. These effects might lead to early damage of joint structure, which will endanger the structural integrity and load carrying capacity of aircraft components. In the present study, transient heat transfer and thermo-structural analysis of C/SiC composite and superalloy bolted joint were carried out by using a commercial FEA software ABAQUS. The stress distributions at hole-edge areas, pre-load loosening, and variation of bolt-hole clearance of CMC bolted joints under transient temperature rises were discussed for better understanding of high temperature structural behaviors. Results showed that pre-load declined with the increase of imposed hot side temperature, due to the thermal expansion mismatch between CMC and superalloy. The bolt-hole clearance for the composite plate decreased, whereas the clearance for the superalloy plate increased with the rise of temperature.

关键词： ceramic matrix composite heat transfer thermal stress pre-load bolt-hole clearance

SKIP Confers Osmotic Tolerance during Salt Stress by Controlling Alternative Gene Splicing in Arabidopsis

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Molecular Plant 2015年第7期8卷 1038-1052页

作者： Jinlin Feng dingjing Li Zhaoxu Gao Yaru Lu Junya Yu Qian Zheng Shuning Yan wenjiao zhang Hang He Ligeng Ma Zhengge Zhu College of Life Sciences Hebei Normal University Shijiazhuang Hebei 050021 China College of Life Sciences Capital Normal University Beijing 100048 China College of Life Sciences Peking University Beijing 100871 China These authors contributed equally to this article.

Deciphering the mechanisms underlying plant responses to abiotic stress is key for improving plant stress resistance. Much is known about the regulation of gene expression in response to salt stress at the tran- scriptional level; however, little is known about this process at the posttranscriptional level. Recently, we demonstrated that SKIP is a component of spliceosome that interacts with clock gene pre-mRNAs and is essential for regulating their alternative splicing and mRNA maturation. In this study, we found that skip-1 plants are hypersensitive to both salt and osmotic stresses, and that SKIP is required for the alter- native splicing and mRNA maturation of several salt-tolerance genes, including NHXl, CBL1, P5CS1, RCl2A, and PATIO. A genome-wide analysis revealed that SKIP mediates the alternative splicing of many genes under salt-stress conditions, and that most of the alternative splicing events in skip-1 involve intron retention and can generate a premature termination codon in the transcribed mRNA. SKIP also controls alternative splicing by modulating the recognition or cleavage of 5＇ and 3＇ splice donor and acceptor sites under salt-stress conditions. Therefore, this study addresses the fundamental question of how the mRNA splicing machinery in plants contributes to salt-stress responses at the posttranscriptional level, and provides a link between alternative splicing and salt tolerance.

关键词： salt response osmotic tolerance SKIP alternative splicing posttranscriptional regulation

价值共创视角下虚拟旅游直播的观众行为意愿影响机制研究

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旅游论坛 2024年第4期17卷 30-41页

作者：罗卉张文姣梁增贤中山大学旅游学院广东珠海519082 中山大学人工智能学院广东珠海519082

随着虚拟旅游直播的快速发展,如何促使观看旅游直播的观众转化为实地游客,成为旅游企业和学术研究关注的重要问题。文章从价值共创的视角出发,以北京故宫博物院为例,探讨了虚拟旅游直播的观众行为意愿影响机制和虚拟旅游直播持续参与意... 详细信息

随着虚拟旅游直播的快速发展,如何促使观看旅游直播的观众转化为实地游客,成为旅游企业和学术研究关注的重要问题。文章从价值共创的视角出发,以北京故宫博物院为例,探讨了虚拟旅游直播的观众行为意愿影响机制和虚拟旅游直播持续参与意愿向实地旅游意愿转换的边界条件。结果表明:观众间互动的参与度和共鸣感染会对沉浸感和信任产生显著的正向影响,但认知交流则不会;直播内容形式和感知真实性均会对沉浸感和信任产生显著的正向影响;信任会对两种意愿产生显著的影响,但沉浸感只会影响虚拟旅游直播的持续参与意愿;高频率和丰富观看经验会削弱虚拟旅游直播持续参与意愿向实地旅游意愿的转化。文章也为旅游直播的发展提出了针对性的建议。

关键词：虚拟旅游直播价值共创社会交换理论沉浸感信任

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硬质黏土淹没射流冲刷试验研究

人民黄河 2024年第2期46卷 152-156,162页

作者：潘振东赵荥王仲梅张文皎张世宝华北水利水电大学水利学院河南郑州450045 黄河水利委员会黄河水利科学研究院河南郑州450003 水利部黄河下游河道与河口治理重点实验室河南郑州450003 河南省黄河流域生态环境保护与修复重点实验室河南郑州450003

近年来自吸式管道排沙系统以其省水、高效、廉价等优势,逐渐成为水库清淤的主要措施之一,然而在遇到土颗粒较细、淤积历时较长的硬质黏土时,它的清淤效果下降明显。为了探究硬质黏土的破土机制和起动影响因素,采用模型试验的方法,选取... 详细信息

近年来自吸式管道排沙系统以其省水、高效、廉价等优势,逐渐成为水库清淤的主要措施之一,然而在遇到土颗粒较细、淤积历时较长的硬质黏土时,它的清淤效果下降明显。为了探究硬质黏土的破土机制和起动影响因素,采用模型试验的方法,选取一种黏性泥沙,通过负压固结的方式制备硬质黏土样,然后进行了不同出口流速、喷嘴尺寸和射流靶距的直立淹没射流试验。试验结果表明,鉴于土样存在黏性,其受冲刷破土机制与无黏性土存在较大差异,冲坑发育过程存在一定的随机性和自相似性,并且射流冲刷效率与射流出口流速和喷嘴尺寸成正比、与射流靶距成反比,同时射流靶距对冲刷坑形态的影响最为明显。

关键词：水库清淤工程硬质黏土射流冲刷出口流速喷嘴尺寸射流靶距

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融合注意力机制和结构线提取的图像卡通化

浙江大学学报（工学版） 2024年第8期58卷 1728-1737页

作者：李灿林王新玥马利庄邵志文张文娇郑州轻工业大学计算机与通信工程学院河南郑州450000 上海交通大学计算机科学与工程系上海200240 中国矿业大学计算机科学与技术学院江苏徐州221116

为了解决图像卡通化没有突出表达图像中的重要特征信息及边缘处理不足的问题,提出融合注意力机制和结构线提取的图像卡通化方法.构建融合注意力机制的生成器网络,通过空间和通道融合特征间的联系,从不同的特征中提取更加重要和丰富的图... 详细信息

为了解决图像卡通化没有突出表达图像中的重要特征信息及边缘处理不足的问题,提出融合注意力机制和结构线提取的图像卡通化方法.构建融合注意力机制的生成器网络,通过空间和通道融合特征间的联系,从不同的特征中提取更加重要和丰富的图像信息.为了更好地实现对卡通纹理的学习,设计与全局并行的线提取区域处理模块(LERM),以便对卡通纹理的边缘区域进行对抗性训练.该方法不仅在重要区域和细节方面生成了高感知质量的卡通化图像,而且避免了内容和颜色的损失.大量的实验结果表明,利用该方法取得了更好的卡通风格化效果,验证了该方法的有效性,.

关键词：生成式对抗网络图像卡通化注意力机制结构线提取边缘检测

Bolt Design of Ceramic Matrix Composite and Superalloy Bolted Joint Based on Damage Failure Load

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Journal of Harbin Institute of Technology(New Series) 2021年第2期28卷 55-61页

作者： Chao Lv Shuyuan Zhao Zhengyu Li Zeliang Pu Jianglong Dong Xinyang Sun wenjiao zhang China Academy of Aerospace Aerodynamics Beijing 100074China National Key Laboratory of Science and Technology for National Defense on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China School of Aeronautics and Astronautics Harbin Institute of TechnologyHarbin 150001China Engineering College Northeast Agricultural UniversityHarbin 150030China

Ceramic matrix composite(CMC)and superalloy bolted joints are commonly used high temperature connection structures in aerospace and aeronautical fields.In this paper,a finite element model coupled with progressive damage analysis of 2D C/SiC composites and superalloy bolted joint was implemented to simulate the uniaxial tensile loading process by using the ABAQUS finite element software.The parametric effects of raised head bolt on stress distribution,tensile performance,and damage process were studied for the CMC⁃superalloy bolted joint structures.The results showed that the final failure load increased first to the maximum value,and then decreased with the rise of bolt diameter,bolt head diameter,and bolt head thickness,respectively.When the three parameters were 5.0 mm,9.5 mm,and 2.8 mm for the current studied bolt configuration,the joint structure gave the maximum load bearing capacity for the considered parameter ranges.It was also found that around 42%potential improvement in load bearing capacity could be achieved by very small adjustments in bolt parameters of the joints.

关键词： 2D C/SiC composite progressive damage analysis tensile properties bolted joint bolt parameters

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GFRP筋再生混凝土梁受弯承载力研究

建筑结构 2024年第8期54卷 50-56页

作者：孔祥清韩硕刚建明陈信展王学志章文姣辽宁工业大学土木建筑工程学院锦州121001 锦州石化工程建设监理有限公司锦州121001

为研究GFRP筋再生混凝土梁(GFRP-RAC)的受弯承载力,完成了5根配GFRP筋、1根配BFRP筋和1根配钢筋的再生混凝土梁抗弯试验,分析了不同再生骨料取代率、纵筋类型以及纵筋配筋率等因素对各试验梁开裂荷载和极限承载力的影响。结果表明:再生... 详细信息

为研究GFRP筋再生混凝土梁(GFRP-RAC)的受弯承载力,完成了5根配GFRP筋、1根配BFRP筋和1根配钢筋的再生混凝土梁抗弯试验,分析了不同再生骨料取代率、纵筋类型以及纵筋配筋率等因素对各试验梁开裂荷载和极限承载力的影响。结果表明:再生骨料取代率对开裂荷载的影响较大,而纵筋类型及纵筋配筋率对其影响不明显;当再生骨料取代率由0增加至50%和100%时,试验梁开裂荷载分别减小了7.9%和17.3%;极限承载力受再生骨料取代率影响较小而受纵筋配筋率影响较大,当GFRP-RAC梁纵筋配筋率由0.38%提高至0.6%和1.17%时,极限荷载分别提升了17.9%和52.5%。另外,结合国内外规范对GFRP-RAC梁的受弯承载力进行对比分析,并基于试验数据和相关试验结果的回归分析,得到开裂荷载修正系数αcr,开裂荷载修正后的计算值与试验值吻合较好。

关键词： GFRP筋再生混凝土受弯承载力再生骨料取代率纵筋配筋率

Characteristics of gut microbiota determine effects of specific probiotics strains in patients with functional constipation

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Chinese Medical Journal 2024年第1期137卷 120-122页

作者： Haohao zhang Lijuan Sun Zhixin Zhao Yao Zhou Yuyao Liu Nannan zhang Junya Yan Shibo Wang Renlong Li Jing zhang Xueying Wang wenjiao Li Yan Pan Meixia Wang Bing Luo Mengbin Li Zhihong Sun Yongxiang Zhao Yongzhan Nie State Key Laboratory of Targeting Oncology National Center for International Research of Bio-targeting TheranosticsGuangxi Key Laboratory of Bio-targeting TheranosticsCollaborative Innovation Center for Targeting Tumor Diagnosis and TherapyGuangxi Talent Highland of Bio-targeting TheranosticsGuangxi Medical UniversityNanningGuangxi 530021China State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and National Clinical Research Center for Digestive Diseases Xijing Hospital of Digestive DiseasesFourth Military Medical UniversityXi’anShaanxi 710032China Key Laboratory of Resource Biology and Biotechnology in Western China Ministry of EducationSchool of MedicineNorthwest UniversityXi’anShaanxi 710000China Key Laboratory of Dairy Biotechnology and Engineering Ministry of EducationKey Laboratory of Dairy Products ProcessingMinistry of Agriculture and Rural AffairsInner Mongolia Key Laboratory of Dairy Biotechnology and EngineeringInner Mongolia Agricultural UniversityHohhotInner Mongolia 010018China

To the Editor:Probiotics are a promising treatment modality for functional constipation(FC);however,the factors affecting individual responses to probiotics remain unclear.Growing evidence has identified that there is a strong relationship among the gut microbiota and constipation and related gut-brain axis.[1]The gut microbiota may modulate the gut functions via gut metabolites or trigger the release of gut hormones,such as peptide YY,gastric inhibitory polypeptide,and 5-hydroxytryptamine.[2]In turn,gut hormones affect gut secretion,motility,and sensation through their receptors located on epithelial,enteric,and smooth muscle cells.[2]Based on these findings,exogenous probiotics have been used in patients with constipation;however,few have produced consistent results.[3]In this study,we investigated the efficacy and safety of several specific probiotics strains for constipation,and also examined the potential reasons for the individualized effects of probiotics,which may facilitate interventional decisionmaking for FC patients.

关键词： constipation patients sensation

高温与冲击耦合作用下双钢管混凝土柱动态响应数值模拟研究

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振动与冲击 2023年第10期42卷 92-102,171页

作者：孔祥清张惠玲张文萍付莹章文姣辽宁工业大学土木建筑工程学院辽宁锦州121001 松山湖材料实验室广东东莞523000

为研究双钢管混凝土(concrete-filled double-tube,CFDT)柱在高温下的抗冲击性能,利用ABAQUS有限元软件建立CFDT柱在高温与冲击耦合作用下的有限元模型,考虑材料的温度软化、应变率强化效应以及轴力的影响,并通过已有CFDT柱的火灾试验... 详细信息

为研究双钢管混凝土(concrete-filled double-tube,CFDT)柱在高温下的抗冲击性能,利用ABAQUS有限元软件建立CFDT柱在高温与冲击耦合作用下的有限元模型,考虑材料的温度软化、应变率强化效应以及轴力的影响,并通过已有CFDT柱的火灾试验和常温下侧向冲击试验进行了分段验证。在此基础上,从冲击力、跨中位移、荷载分布情况与损伤演化等方面分析了不同温度下CFDT柱的抗冲击动态响应,并考虑了不同截面形式、轴压比、冲击速度和混凝土强度对CFDT柱抗冲击性能的影响。研究结果表明,在高温与冲击耦合作用下,CFDT柱主要呈现弯曲破坏,随着温度升高,CFDT柱抗冲击性能和抗弯承载力逐渐降低。CFDT柱的耐火极限是普通钢管混凝土柱的2.1倍。轴力对CFDT柱抗冲击性能产生不利影响,当轴压比从0增加到0.6,高温800℃时构件冲击力平台值下降了32.4%;混凝土强度对高温下CFDT柱抗冲击性能有显著影响,高温800℃时混凝土强度由40 MPa增加到60 MPa,构件冲击力平台值提高了22.8%。

关键词：双钢管混凝土(CFDT)柱高温冲击耦合作用有限元分析