检索结果-南通市图书馆

Reliability analysis of aero-engine blades considering nonlinear strength degeneration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2013年第3期26卷 631-637页

作者： Lin Jiewei Zhang Junhong Yang Shuo Bi Fengrong State key laboratory of Engines Tianjin University

To comprehensively consider the effects of strength degeneration and failure correlation, an improved stress–strength interference （SSI） model is proposed to analyze the reliability of aeroengine blades with the fatigue failure mode. Two types of TC4 alloy experiments are conducted for the study on the damage accumulation law. All the parameters in the nonlinear damage model are obtained by the tension–compression fatigue tests, and the accuracy of the nonlinear damage model is verified by the damage tests. The strength degeneration model is put forward on the basis of the Chaboche nonlinear damage theory and the Griffith fracture criterion, and determined by measuring the fatigue toughness during the tests. From the comparison of two kinds of degeneration models based on the Miner’s linear law and the nonlinear damage model respectively, the nonlinear model has a significant advantage on prediction accuracy especially in the later period of life. A time-dependent SSI reliability model is established. By computing the stress distribution using the finite element （FE） technique, the reliability of a single blade during the whole service life is obtained. Considering the failure correlation of components, a modified reliability model of aero-engine blades with common cause failure （CCF） is presented. It shows a closer and more reasonable process with the actual working condition. The improved reliability model is illustrated to be applied to aero-engine blades well, and the approach purposed in this paper is suitable for any actual machinery component of aero-engine rotor systems.

关键词： Blade Fatigue Nonlinear strength degeneration Reliability Stress–strength interference

Spectral tomographic imaging with aplanatic metalens

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2019年第1期8卷 258-265页

作者： Chen Chen Wange Song Jia-Wern Chen Jung-Hsi Wang Yu Han Chen Beibei Xu Mu-Ku Chen Hanmeng Li Bin Fang Ji Chen Hsin Yu Kuo Shuming Wang Din Ping Tsai Shining Zhu Tao Li National laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and IntegrationJiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied SciencesNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures NanjingChina Research Center for applied Sciences Taipei11529 TaiwanChina Department of Physics Taiwan UniversityTaipei10617 TaiwanChina Graduate Institute of Electronics Engineering Taiwan UniversityTaipei10617 TaiwanChina

Tomography is an informative imaging modality that is usually implemented by mechanical scanning,owing to the limited depth-of-field(DOF)in conventional ***,recent imaging systems are working towards more compact and stable architectures;therefore,developing nonmotion tomography is highly ***,we propose a metalens-based spectral imaging system with an aplanatic GaN metalens(NA=0.78),in which large chromatic dispersion is used to access spectral focus tuning and optical zooming in the visible *** the function of wavelength-switched tomography was confirmed on cascaded samples,this aplanatic metalens is utilized to image microscopic frog egg cells and shows excellent tomographic images with distinct DOF features of the cell membrane and *** approach makes good use of the large diffractive dispersion of the metalens and develops a new imaging technique that advances recent informative optical devices.

关键词： tuning switched dispersion

Electrical Characteristics of High-Performance ZnO Field-Effect Transistors Prepared by Ultrasonic Spray Pyrolysis technique

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第1期28卷 179-181页

作者： YI Ming-Dong XIE Ling-Hai LIU Yu-Yu DAI Yan-Eeng HUANG Jin-Ying key laboratory for Organic Electronics & Information Displays and Institute of Advanced Materials Nanjing University of Posts and Telecommunications Nanjing 210046 State key laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Graduate School of the Chinese Academy of Sciences Chinese Academy of Sciences Changchun 130022

We have fabricated ZnO-based thin-film transistors （TFTs） by low-cost ultrasonic spray pyrolysis. The devices exhibit high saturation mobility of about 0. 6 cm2 /Vs and on-off current ratio of 10^5. The electrical characteristics of ZnO-based TFTs show that ultrasonic spray pyrolysis technique can be used as a promising approach to attain high-performance electronic devices. Furthermore, the deposition techniques make the operating process attractive for flexible electronics.

关键词： Electronics and devices Semiconductors Surfaces interfaces and thin films

Probabilistic back analysis for geotechnical engineering based on Bayesian and support vector machine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2015年第12期22卷 4778-4786页

作者：陈炳瑞赵洪波茹忠亮李贤 State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences School of Civil Engineering Henan Polytechnic University School of Resource and Environmental Engineering Wuhan University of Science and Technology

Geomechanical parameters are complex and *** order to take this complexity and uncertainty into account,a probabilistic back-analysis method combining the Bayesian probability with the least squares support vector machine(LS-SVM) technique was *** Bayesian probability was used to deal with the uncertainties in the geomechanical parameters,and an LS-SVM was utilized to establish the relationship between the displacement and the geomechanical *** proposed approach was applied to the geomechanical parameter identification in a slope stability case study which was related to the permanent ship lock within the Three Gorges project in *** results indicate that the proposed method presents the uncertainties in the geomechanical parameters reasonably well,and also improves the understanding that the monitored information is important in real projects.

关键词： geotechnical engineering back analysis uncertainty Bayesian theory least square method support vector machine(SVM)

Lattice Boltzmann model for combustion and detonation

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2013年第1期8卷 94-110页

作者： Bo Yan Ai-Guo Xu Guang-Cai Zhang Yang-Jun Ying Hua Li National key laboratory of Computational Physics Institute of Applied Physics and Co~putational Mathe'maties P. O. Box 8009-26 Beijing 100088 China

In this paper we present a lattice Boltzmann model for combustion and detonation. In this model the fluid behavior is described by a finite-difference lattice Boltzmann model by Gan et al. [Physica A, 2008, 387: 1721]. The chemical reaction is described by the Lee-Tarver model [Phys. Fluids, 1980, 23: 2362]. The reaction heat is naturally coupled with the flow behavior. Due to the separation of time scales in the chemical and thermodynamic processes, a key technique for a successful simulation is to use the operator-splitting scheme. The new model is verified and validated by well-known benchmark tests. As a specific application of the new model, we studied the simple steady detonation phenomenon. To show the merit of LB model over the traditional ones, we focus on the reaction zone to study the non-equilibrium effects. It is interesting to find that, at the von Neumann peak, the system is nearly in its thermodynamic equilibrium. At the two sides of the von Neumann peak, the system deviates from its equilibrium in opposite directions. In the front of von Neumann peak, due to the strong compression from the reaction product behind the von Neumann peak, the system experiences a sudden deviation from thermodynamic equilibrium. Behind the von Neumann peak, the release of chemical energy results in thermal expansion of the matter within the reaction zone, which drives the system to deviate the thermodynamic equilibrium in the opposite direction. From the deviation from thermodynamic equilibrium, Δ m *, defined in this paper, one can understand more on the macroscopic effects of the system due to the deviation from its thermodynamic equilibrium.

关键词： lattice Boltzmann method Lee-Tarver model viscous detonation deviation from equilibrium

High pressure floating-zone growth and property characterization of Cr-doped hexagonal YMnO_3 crystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2017年第9期33卷 1061-1066页

作者： Feng Wan Xiaojun Bai Kaikai Song Jianbang Zheng Xin Lin Chongde Cao Department of applied Physics Northwestern Polytechnical University School of Mechanical Electrical & Information EngineeringShandong University (Weihai) State key laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical University

Large crystal growth of Cr-doped h-YMnO3has been investigated by using a high pressure optical floatingzone method. The size of the grown crystals is typically 60–70 mm in length and 4–5 mm in diameter. The structure of the grown crystals is analyzed by powder X-ray diffraction and scanning electron *** defects in the as-grown crystals, including low-angle grain boundary and inclusions are studied. An off-stoichiometric phenomenon is found with a slight Cr deficiency in different parts. The relationship between defects and growth conditions during crystal growth is also discussed. The magnetic properties show spin-glass phase features with weak ferromagnetic behavior below 30 K.

关键词： High pressure floating zone technique Crystal growth Cr-doped YMnO3 High vapor pressure compound

Investigation of Portevin–Le Chatelier Band Strain and Elastic Shrinkage in Al-Based Alloys Associated with Mg Contents

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2017年第6期33卷 580-586页

作者： Yulong Cai Suli Yang Shihua Fu Di Zhang Qingchuan Zhang CAS key laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China State key laboratory for Advanced Metals and Materials University of Science and Technology Beijing

The Portevin–Le Chatelier（PLC） effect in Al–2.30wt%Mg, Al–4.57wt%Mg and Al–6.91wt%Mg alloys has been investigated at various applied strain rates at room temperature in this study. Three-dimensional digital image correlation（3D-DIC） technique was applied to obtaining the further insight into the spatiotemporal characteristics, in particular the influence of Mg content on deformation behaviors. Mg content has a pronounced effect on serration characteristics, including the serration type and amplitude; Mg content tends to weaken the spatial correlation of the propagative bands. Additionally, the serration amplitude linearly increases with the maximum PLC band strain; high Mg content generates a higher PLC band strain at a given serration amplitude compared with low Mg content. Mg content is found to be effective to enhance the serration amplitude, the maximum PLC band strain and also the amount of elastic shrinkage outside PLC bands.

关键词： Mg content Al–Mg alloy Portevin–Le Chatelier effect Digital image correlation Elastic shrinkage

Morphology and Performance of Poly（2-methoxy-5-（20-ethyl- h exyloxy）-p-p he nyle n evi nylene）（M E H-PPV）：（6,6）-Phenyl-C61 - butyric Acid Methyl Ester （PCBM） Based Polymer Solar Cells

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2013年第6期31卷 731-736页

作者： Leijing Liu Svetlana van Bavel Shanpeng Wen Xiaoniu Yang Joachim Loos State key laboratory of Supramolecular Structure and Materials Jilin University Changchun Jilin 130012 China State key laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin 130022 China laboratory of Materials and Interface Chemistry Laboratory of Polymer Technology and Dutch Polymer Institute Eindhoven University of Technology PO Box 513 NL-5600 MB Eindhoven The Netherlands

Polymer solar cells were fabricated based on composite fihns of poly（2-methoxy-5-（2＇-ethyl-hexyloxy）-1,4- phenylenevinylene）（MEH-PPV）：fullerene derivative （6,6）-phenyl-C61-butyric acid methyl ester （PCBM） with weight blend ratio of 1 ： 3, 1 ： 4 and 1 ： 5, spin-coated from chloroform （CF）, chlorobenzene （CB）, and o-dichlorobenzene （ODCB） solutions, respectively. Photoinduced current and power conversion efficiency （PCE） of the devices show a dependence on the solvents. The solar cells have the highest PCE at 1 ： 5 blend ratio. Transmis- sion electron microscopy （TEM） morphology reveals that there are some voids in MEH-PPV：PCBM films. The void number decreases with the solvent from CF to CB and ODCB. We found the voids are located at the bottom of the films through electron tomography technique by TEM and film bottom-side morphology study by atomic force microscopy. The charge carrier transport efficiency and collection efficiency should decrease greatly due to the voids, and the more voids the film has, the more degree the efficiencies decrease. PCE of the solar cell prepared from CF is lower than that of the solar cells prepared from CB and ODCB. The void phenomenon of MEH-PPV：PCBM based solar cell and method to investigate the void position provide an experimental evidence and research mentality to fabricate polymer solar cell with high performance.

关键词： solar cell morphology solvent effects thin films void

Property modulations of two-dimensional materials under compression

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 Energy 2023年第4期2卷 103-119页

作者： Zhen Wu Yuxi Wang Yunjie Dou Lin Zhou Jia Zhu National laboratory of Solid State Microstructures College of Engineering and Applied Sciences and Jiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210093China

Two-dimensional(2D)materials have attracted considerable research interest,leading to significant advances in energy applications in recent years,such as lithium batteries,catalysis,electronics,and thermoelectrics,owing to their rich controllable properties and excellent ***,pressure has been successfully employed as an effective method for property modulation of 2D materials,through tuning electronic orbitals and bonding *** this review,we summarize recent progresses in the pressure-driven property modulations and elucidate the underlying mechanism of the pressure modulation of 2D ***,we identify the remaining challenges and opportunities in this new,vibrant area of research for energy conversion and *** the different property modulation strategies,the in situ application of high pressure is systematically identified as a promising knob for 2D *** review is expected to inspire further research on the fundamental understanding and practical applications of high-pressure modulation in 2D materials.

关键词： two-dimensional material property modulations hydrostatic pressure diamond anvil cell energy applications