检索结果-南通市图书馆

Science China(Technological Sciences) 2019年第6期62卷 989-995页

作者： LI ShaoLin QI HongYu song jianan YANG XiaoGuang CHE Chang School of Energy and Power Engineering Beihang University Beijing 100191 China Collaborative Innovation Center of Advanced Aero-Engine Beijing 100191 China School of Materials Science and Engineering Beihang University Beijing 100191 China

This work investigates the failure mechanism of an air plasma spraying(APS) thermal barrier coatings(TBCs) with various bond coat(BC) surface toughness under constant temperature loading condition. Results show that the increased BC surface roughness decreased the lifetime. Moreover, the relationship between the TGO depth and the lifetime can be well described by linear *** failure mechanism of the TBCs samples was studied by cross-sectional morphologies observation and using the finite element method(FEM). Cracks in the TBCs samples with higher BC surface roughness are initiated from the defects on the BC caused by Al depletion in the BC layer. However, cracks in the samples of TBCs with lower BC surface roughness condition preferentially occur at the TC-TGO interface. This finding could be attributed to the high mismatch stresses in the TC-TGO interface.

关键词： thermal barrier coatings roughness failure mechanism air plasma spraying

Experimental study and numerical modeling of the damage evolution of thermal barrier coating systems under tension

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第12期61卷 1882-1888页

作者： LI ShaoLin YANG HongWei QI HongYu song jianan YANG XiaoGuang SHI DuoQi School of Energy and Power Engineering Beihang University Beijing 100191 China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191 China

This study investigated the damage evolution(i.e., formation of vertical cracks, transformation of vertical cracks to interfacial crack and delamination) of thermal barrier coating systems under tension by using experimental and numerical *** results revealed that the first transverse crack that was perpendicular to the load direction occurred when the strain of the top coat reached 0.5%. The full-scale strain of the top coat layer obtained by using the Digital Image Correlation technique indicated that surface cracks formed due to the coalescence of micro-cracks. Moreover, the results of the finite element method demonstrated that the vertical cracks initiated from the coating surface and extended through the thickness of the coatings. The density of the surface cracks was used as a damage evolution indicator such that numerical simulation could predict the cracking behaviour under tension loading. The results were consistent with those of the experimental study.

关键词： damage evolution interfacial thermal barrier coating systems digital image correlation

A physically-based representative stress methodology for predicting stress rupture life of Ni-based DS superalloy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第6期36卷 174-185页

作者： Jia HUANG Zhenzhuo HE Shuangqi LYU Xiaoguang YANG Duoqi SHI Yantao SUN Yongzhao LYU Zhizhong FU Guolei MIAO jianan song School of Aeronautics and Astronautics Central South UniversityChangsha 410083China Aviation Engineering College Civil Aviation University of ChinaGuanghan 618307China School of Energy and Power Engineering Beihang UniversityBeijing 100083China Beijing Aeronautical Engineering Technical Research Center Beijing 100076China Chengdu Holy Industry&Commerce Corp.LTD Pengzhou 611936China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China

Smooth and three types of U-shape single-edge notched plate specimens adopted to experimentally investigate stress rupture behavior of Ni-based Directionally Solidified(DS)superalloy at 850℃ exhibit notch weakening effect and multi-source cracking initiation near the notch ***,stress rupture behavior of smooth and V-shape notched round bars at 1040℃ revealed by Li et al indicates notch strengthening effect and creep micro-holes originating mostly from the central portion.A combined creep-viscoplastic constitutive model is employed to analyze the distribution of stress,strain and stress Triaxial Factor(TF)near the notch *** different stress distribution and creep restraint between asymmetric notched plate specimens and symmetric notched round bars are the main reasons for the corresponding failure ***,a good qualitative relationship exists between TF value and stress rupture life of notched ***,the area with maximum TF value(TF_(max))is highly consistent with creep damage initiation ***,based on the distribution characteristics of the initial tensile loading,a representative stress method independent of time-changing creep load at the location of TF_(max) is conducted for life *** predicted results of both smooth and notched plate specimens and round bars agrees well with the experimental results.

关键词： Creep Life model Ni-based superalloy Notched round bar Single edge notch

Mass Production of Ultrafine Fibers by a Versatile Solution Blow Spinning Method

在线全文

学校读者我要写书评

暂无评论

Accounts of Materials Research 2021年第6期2卷 432-446页

作者： Chao Jia Lei Li jianan song Ziwei Li Hui Wu State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China

CONSPECTUS:Ultrafine fiber materials have shown great application prospects in many fields due to their superior properties,including large specific surface area,high porosity,low density,and good mechanical *** spinning methods have been developed to prepare ultrafine fiber materials,including electrospinning,solution blow spinning(SBS),centrifugal spinning,melt-blowing,*** them,SBS combines the merits of electrospinning and *** electrospinning,SBS uses a high-speed airflow as the driving force to stretch the spinning solution,and solvent evaporates rapidly in the process of liquid flow movement,thus obtaining ultrafine *** with other spinning methods,SBS has many advantages,including simple and safe process,high efficiency,suitability for a wider range of solution systems,controllability of fiber structure and diameter,*** its development in 2009,SBS has received widespread attention and has become an efficient and versatile tool for fabricating various ultrafine fiber materials with controlled microstructures and *** blow spun fibers can be assembled into a variety of configurations,including sponges,mats,papers,and *** thickness of the fiber materials also can be easily regulated,which is an important advantage of SBS over *** various forms of the blow spun fibers enable them to have a wide range of applications in environmental remediation,flexible electronic devices,energy storage and conversion,and biomedicine,among *** this Account,we review the recent progress of SBS and mainly focus on our group’s contributions to this *** begin with an introduction to the principles and setup of SBS,including(1)the mechanism of fiber formation from spinning solution under the action of airflow;(2)the effects of spinning solution parameters(concentration and viscosity),processing parameters(gas pressure,feeding rate and working distance),and ambient conditions on

关键词： ceramic spinning fibers

An ultralight,flexible,and biocompatible all-fiber motion sensor for artificial intelligence wearable electronics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Flexible Electronics 2022年第1期6卷 235-242页

作者： Sen Lin Shuang Hu Wei song Miaoqing Gu Junchen Liu jianan song Zhenglian Liu Ziwei Li Kun Huang Yufeng Wu Ming Lei Hui Wu School of Physical Science and Technology Guangxi UniversityNanning 530004China Advanced Institute for Brain and Intelligence Guangxi UniversityNanning 530004China State Key Laboratory of Information Photonics and Optical Communications and School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

New-generation human body motion sensors for wearable electronics and intelligent medicine are required to comply with stringent requirements in terms of ultralight weight,flexibility,stability,biocompatibility,and extreme ***,conventional sensors are hard to fulfill all these criteria due to their rigid structure,high-density sensing materials used as the constituents,as well as hermetical and compact assembly ***,we report an ultralight sensing material based on radial anisotropic porous silver fiber(RAPSF),which has been manufactured by phase separation and temperature-controlled grain growth strategy on a modified blow-spinning *** resistance of RAPSF could be dynamically adjusted depending on the deflected ***,an all-fiber motion sensor(AFMS)with an ultra-low density of 68.70 mg cm^(−3) and an overall weigh of 7.95 mg was fabricated via layer-by-layer *** sensor exhibited outstanding flexibility,breathability,biocompatibility,and remarkable body motion recognition ***,the AFMS was shown to have great potential as an artificial intelligence throat sensor for throat state identification at the accuracy above 85%,allowing one to spot the early onset of the viral throat illness.

关键词： fiber artificial motion

Large-scale blow spinning of heat-resistant nanofibrous air filters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2020年第3期13卷 861-867页

作者： Ziwei Li jianan song Yuanzheng Long Chao Jia Zhenglian Liu Lei Li Cheng Yang Junchen Liu Sen Lin Haiyang Wang Yibo Liu Minghao Fang Hui Wu State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China School of Materials Science and Technology China University of GeosciencesBeijing100083China State Key Laboratory of Information Photonics and Optical Communications and School of Science Beijing University of Posts and TelecommunicationsBeijing100876China

Particulate matter(PM)pollution has become a serious problem worldwide and various kinds of nanofibrous filters aiming to solve the problem have been *** is urgent to remove PM from high-temperature pollution sources,such as industrial emissions,coal furnaces,and automobile exhaust ***,filtration at pollution sources remains challenging because most existing air filters are not resistant to high ***,heat-resistant polyimide(PI)nanofibrous air filters are fabricated via a simple and scalable solution blow-spinning *** air filters show excellent thermal stability at high temperature up to 420℃.They exhibit a filtration efficiency as high as 99.73%at ambient temperature and over 97%at 300℃.In addition,a field test shows that the filters remove>97%of PM from the car exhaust ***,the blow-spun PI nanofibrous membranes combined with the facile preparation strategy have great potential in high temperature air filtration fields and other similar applications such as water purification and protein separation.

关键词： air filters heat-resistant blow spinning nanofibers

A large-area AgNW-modified textile with high-performance electromagnetic interference shielding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Flexible Electronics 2020年第1期4卷 102-108页

作者： Junchen Liu Sen Lin Kai Huang Chao Jia Qingmin Wang Ziwei Li jianan song Zhenglian Liu Haiyang Wang Ming Lei Hui Wu State Key Laboratory of Information Photonics and Optical Communications and School of Science Beijing University of Posts and Telecommunications100876 BeijingChina State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua University100084 BeijingChina

Manufacturing a flexible,light,large-area,and high-efficiency electromagnetic shielding materials in a straightforward and cost-effective manner presently remains a significant *** this work,we propose a conductive network design and verify its electromagnetic interference(EMI)shielding effectiveness(SE)by *** the structure and parameters obtained by simulation,we prepare a flexible EMI shielding material using silver nanowires(AgNWs)/polyvinyl butyral(PVB)ethanol solution and textile substructure via a facile immersing *** the frequency range of 5-18 GHz,the AgNWs/PVB textile with 1.4 mm thickness achieves an EMI SE of 59 dB,which exceeds the requirements for commercial *** to the low density of 56 mg/cm^(3),specific shielding effectiveness(SSE)of this material reaches 1053 dB m^(3)/*** is found that the AgNWs/PVB textile is more resistant to washing with water and oxidation than AgNWs textile without a PVB *** a result,the conductivity of AgNWs/PVB textile exhibits no change after washing with water and varies slightly after being kept in hot *** find that a signal monitor is unable to detect a signal emitted by a mobile phone from a jacket lined with AgNWs/PVB ***/PVB textile with these properties can be mass-produced as high-efficiency EMI shielding material for commercial applications.

关键词： high shielding silver

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

新时代检察权宪法定位省思

河南大学学报（社会科学版） 2023年第1期63卷 53-57,153页

作者：宋甲楠郑州大学法学院河南郑州450001

检察权的性质与地位问题事关检察制度的根本和发展方向,在学术界和实务界长期存在争论,对此可从法教义学和功能主义理论视角进行检视。检察权是一种具有独立的宪法地位和法律监督功能的国家权力;检察权地位具有独立性,其内涵多元,包括... 详细信息

检察权的性质与地位问题事关检察制度的根本和发展方向,在学术界和实务界长期存在争论,对此可从法教义学和功能主义理论视角进行检视。检察权是一种具有独立的宪法地位和法律监督功能的国家权力;检察权地位具有独立性,其内涵多元,包括“四大权能”,即“诉讼权能”“诉讼监督权能”“审查权能”“侦查调查权能”。正确把握新时代检察权的意蕴,有助于推动“四大检察”充分发展,提升检察权的法律监督质效。

关键词：人民检察院检察权宪法定位法律监督 “四大权能”

Room-temperature production of silver-nanofiber film for large-area, transparent and flexible surface electromagnetic interference shielding

在线全文

学校读者我要写书评

暂无评论

npj Flexible Electronics 2019年第1期3卷 56-63页

作者： Sen Lin Haiyang Wang Fan Wu Qingmin Wang Xiaopeng Bai Di Zu jianan song Dong Wang Zhenglian Liu Ziwei Li Nian Tao Kai Huang Ming Lei Bo Li Hui Wu State Key Laboratory of Information Photonics and Optical Communications and School of Science Beijing University of Posts and Telecommunications100876 BeijingChina State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua University100084 BeijingChina Advanced Materials Institute Shenzhen Graduate SchoolTsinghua University518055 ShenzhenChina School of Mechanical Engineering Nanjing University of Science&Technology210094 NanjingChina

A kind of pollution known as electromagnetic interference(EMI),which results from ubiquitous usage of various electronic communication and military radar equipment,has been receiving increasing attention ***,large-area EMI shielding on transparent and/or curved surfaces,including building windows,curved glass wall,and special requirements spaces(SRSs),remains hard to *** this paper,a silver nanofiber(AgNF)based flexible and transparent EMI shielding film was successfully assembled via a room-temperature roll-to-roll production *** transparent application scenario,AgNF with 89%transmittance in visible range and 1μm thickness shows~20 dB shielding efficiency(EMI SE).On the other hand,total shielding(>50 dB)is obtained when the thickness of AgNF increases to 10μm,while its transmittance in visible range remains higher than 75%.Considering the facile and scale-free production technology,this material can be readily applied in large-scale,transparent,and/or SRSs EMI shielding.

关键词： transparent silver film

加布里埃尔·祖克曼对公共经济学的贡献——2023年度约翰·贝茨·克拉克奖得主学术贡献评介

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

经济学动态 2023年第6期 149-160页

作者：张延宋嘉楠北京大学经济学院 100080

加布里埃尔·祖克曼是较早从定量化角度研究财富隐藏和逃税现象的经济学家,通过离岸金融机构的微观泄露数据测算出斯堪的纳维亚国家富人群体惊人的避税总量,创新性地以企业盈利性计量方式估算了全球范围内的跨国企业利润转移量,并通过... 详细信息

加布里埃尔·祖克曼是较早从定量化角度研究财富隐藏和逃税现象的经济学家,通过离岸金融机构的微观泄露数据测算出斯堪的纳维亚国家富人群体惊人的避税总量,创新性地以企业盈利性计量方式估算了全球范围内的跨国企业利润转移量,并通过构建分配式国民账户解释了美国存在的财富分配不平等问题,揭示了掩藏在富裕阶层诸多避税手段下各国庞大的税收损失,推动了公众对财富分配和税收问题的重视。本文分别对加布里埃尔·祖克曼的理论框架、实证方法和学术贡献进行介绍。这有助于辩证审视现存税收制度的得失,并有助于鞭策各国政策制定者通过国际合作和税制改革来减少财富隐藏和避税现象,构建21世纪的经济和社会公平。

关键词：加布里埃尔·祖克曼避税天堂财富不平等利润转移