检索结果-内蒙古大学图书馆

Temperature and electric-field induced phase transitions, and full tensor properties of C-poled domain-engineered tetragonal 0.63Pb(Mg1/3Nb2/3)−0.37PbTiO3 single crystals

引用

Physical Review B 2016年第9期93卷 094104-094104页

作者： Limei Zheng Yujia Jing Xiaoyan Lu Ruixue Wang Gang Liu Weiming Lü Rui Zhang Wenwu Cao Condensed Matter Science and Technology Institute Harbin Institute of Technology Harbin 150080 China Key Laboratory of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin 150001 China Center for High Pressure Science and Technology Advanced Research Shanghai 201203 China Department of Mathematics Materials Research Institute The Pennsylvania State University University Park Pennsylvania 16802 USA

The phase-transition sequence of 0.67Pb(Mg1/3Nb2/3)−0.37PbTiO3 (PMN-0.37PT) single crystals driven by the electric (E) field and temperature is comprehensively studied. Based on the strain-E field loop, polarization-E field loop, and the evolution of domain configurations, the E field along the [011]C induced phase transitions have been confirmed to be as follows: tetragonal (T) → monoclinic (MC)→ single domain orthorhombic (O) phase. As the E field decreases, the induced O phase cannot be maintained and transformed to the MC phase, then to the coexistence state of MC and T phases. In addition, the complete sets of dielectric, piezoelectric, and elastic constants for the [011]C-poled domain-engineered PMN-0.37PT single crystal were measured at room temperature, which show high longitudinal dielectric, piezoelectric, and electromechanical properties (ɛ33T=10661,d33=1052pC/N, and k33=0.766). Our results revealed that the MC phase plays an important role in the high electromechanical properties of this domain-engineered single crystal. The temperature dependence of the domain configuration revealed that the volume fraction of the MC phase decreases with temperature accompanied by the reduction of ɛ33T,d31, and k31 due to the substantially smaller intrinsic properties of the T phase.

关键词： Electric polarization Ferroelectricity Phase transitions Piezoelectricity Ferroelectrics Piezoelectrics Relaxor ferroelectrics Polarization

来源：评论

学校读者我要写书评

暂无评论

Ultrasonic guided waves sensing using optical fiber sensor 7

Ultrasonic guided waves sensing using optical fiber sensor

引用

7th International Conference on structural Health Monitoring of Intelligent Infrastructure, SHMII 2015

作者： Zhou, W. Li, H. Dong, Y. Wang, A. Key Lab. of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China National Key Laboratory of Science and Technology on Tunable Laser Harbin Institute of Technology Harbin150001 China

Optical fiber sensors have been proven that they have potential as ultrasonic guided waves sensor for structural health monitoring and damage detection. They can be used to receive acoustic emission signals from dynamic structural damages or guided waves propagating in waveguide and excited by ultrasonic actuators. Optical fiber sensors based on Mach-Zehnder interferometer were investigated in this work. Their sensing properties were explored experimentally using Lamb waves excited by a piezoelectric wafer in an aluminum plate. Spiral shape with different size was selected to increase their sensitivity. Experiments were also conducted to examine the voltage responses received by this type of sensor, and investigate results of tuning frequency. © 2015, International Society for structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.

关键词： structural health monitoring

来源：评论

学校读者我要写书评

暂无评论

Experimental validation of a signal-based approach for structural earthquake damage detection using fractal dimension of time frequency feature

引用

Earthquake Engineering and Engineering Vibration 2014年第4期13卷 671-680页

作者： Tao Dongwang Mao Chenxi Zhang Dongyu Li Hui Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering Mechanics China Earthquake Administration Key Lab of Structures Dynamic Behavior and Control (Harbin Institute of Technology) Ministry of Education Center of Structural Monitoring and Control School of Civil Engineeing Harbin Institute of Technology

This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature （FDTFF） of displacements, for earthquake damage detection of moment resist frame （MRF）, and validates the approach with shaking table tests. The time frequency feature （TFF） of the relative displacement at measured story is defined as the real part of the coefficients of the analytical wavelet transform. The fractal dimension （FD） is to quantify the TFF within the fundamental frequency band using box counting method. It is verified that the FDTFFs at all stories of the linear MRF are identical with the help of static condensation method and modal superposition principle, while the FDTFFs at the stories with localized nonlinearities due to damage will be different from those at the stories without nonlinearities using the reverse-path methodology. By comparing the FDTFFs of displacements at measured stories in a structure, the damage-induced nonlinearity of the structure under strong ground motion can be detected and localized. Finally shaking table experiments on a 1：8 scale sixteen-story three-bay steel MRF with added frictional dampers, which generate local nonlinearities, are conducted to validate the approach.

关键词： earthquake damage detection time frequency feature fractal dimension signal-based shaking table test frictional damper

来源：评论

学校读者我要写书评

暂无评论

Research on deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire

引用

Jianzhu Jiegou Xuebao/Journal of Building Structures 2014年第3期35卷 110-118页

作者： Hou, Xiaomeng Zheng, Wenzhong Sun, Hongyu Key Laboratory of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin 150090 China

In order to research the deterioration of anchoring performance between anchorages to steel bars for prestressed concrete under fire, 65 prestressed anchorage systems were tested under elevated temperatures. The typical tested prestressed anchorage system was specifically designed, which composed by JXM-clip anchorage, 7 steel bar for prestressed concrete (with a characteristic strength fptk=970 MPa) with surrounding concrete and a loading frame. A total of 29 unsealed prestressed anchorage systems and 18 prestressed anchorage systems with insulation were conducted as transient-state tests, while 18 prestressed anchorage systems were conducted as steady-state tests. The test variables included stress level (0.2~0.7), temperature (20~800°C), insulation (sealing anchorages by grouting, fire resistive coating and sealing anchorages by grouting and coating) and heating rate (10.0, 26.7°C/min). Transient-state test results from unsealed prestressed anchorage systems show that the failure mode of prestressed anchorage system is through slippage of anchorages. Lower the stress level, temperature and heating rate are, the higher will be the failure time in prestressed anchorage systems. In steady-state tests, failure mode of prestressed anchorage system is rupture of steel bar for prestressed concrete in temperature range of 20~400°C, while failure mode is through slippage of anchorages in temperature range of 400~800°C. Anchorages after elevated temperatures can not be applied in new structures. Test results from prestressed anchorage systems with insulation show that failure mode of anchorage systems is through slippage of anchorages, and insulations do not change the failure mode at elevated temperatures. As compared with unsealed prestressed anchorage systems, the failure time of prestressed anchorage systems with insulations is increased above 100%. It is not safe to apply the recommendation of fire resistive coating thickness for steel structures in GB 14907-2002 'Fir

关键词： Failure modes

来源：评论

学校读者我要写书评

暂无评论

Establishment of frost resistance model for autoclaved fly ash bricks

Establishment of frost resistance model for autoclaved fly a...

引用

The 2014 IMSS International Conference on Future Manufacturing Engineering(ICFME 2014)

作者： Shuang Lu Zheng Wang Key Laboratory of Structures Dynamic Behavior and Control Ministry of EducationHarbin Institute of Technology

In cold area,the freeze-thaw cycling durability of building materials is one of the primary influence *** paper studied on the loss ratio of the relative dynamic elastic modulus of the autoclaved fly ash bricks,which is according to the ultrasonic speed after suffering different freeze-thaw *** that,the corresponding numerical model has been established *** results indicate that the calculated results by the model can fit with the experimental data very ***,the model can be applied to predict the service life by using environment parameters as the factors in the model.

关键词： fly ash brick freeze-thaw cycling model dynamic elastic modulus durability

来源：评论

学校读者我要写书评

暂无评论

Hysteretic phase transition sequence in 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 single crystal driven by electric field and temperature

引用

Physical Review B 2015年第18期91卷 184105-184105页

作者： Limei Zheng Xiaoyan Lu Hengshan Shang Zengzhe Xi Ruixue Wang Junjun Wang Peng Zheng Wenwu Cao Condensed Matter Science and Technology Institute Harbin Institute of Technology Harbin 150080 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education School of Civil Engineering Harbin Institute of Technology Harbin 150001 China Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices School of Materials and Chemical Engineering Xi'an Technological University Xi'an 710032 China College of Electronics and Information Hangzhou Dianzi University Hangzhou 310018 China Department of Mathematics and Materials Research Institute Pennsylvania State University University Park Pennsylvania 16802 USA

Domain pattern variations with temperature were studied by polarizing light microscopy for the morphotropic phase boundary composition 0.67Pb(Mg1/3Nb2/3)O3−0.33PbTiO3 (PMN-0.33PT) single crystal. At room temperature, the monoclinic MA phase is the dominant phase in the unpoled crystal, which coexists with a small fraction of the tetragonal (T) phase. The orientation of spontaneous polarization was calculated to be ∼4.8∘ away from the pseudocubic 〈111〉C in the {001}C plane family. Under an electric field of 6 kV/cm along [011]C, a single domain orthorhombic (O) phase was induced but partially switched back to MA a few hours after the removal of the E field. It was found that the temperature induced phase transition sequence of the [011]C poled PMN-0.33PT single crystal is strongly hysteretic. On heating, the phase transition sequence is as follows: coexistence of O phase and MA→rhombohedral→monoclinicMC→cubic(C). On cooling, the phase transition sequence is given by C→T→MA. The complete set of dielectric, piezoelectric, and elastic constants for the [011]C poled PMN-0.33PT single crystal was measured, which showed the strong feature of the single domain O phase with high shear (d15=2321pC/N,d24=1941pC/N) and low longitudinal piezoelectric coefficients (d33=165pC/N).

关键词： SINGLE crystals ELECTRIC fields TEMPERATURE POLARIZATION (Electricity) PIEZOELECTRIC devices

来源：评论

学校读者我要写书评

暂无评论

Damage detection and compressive behavior of concrete after impacting

引用

Jianzhu Jiegou Xuebao/Journal of Building Structures 2014年第SUPPL.1期35卷 58-64页

作者： Tian, Yubin Huang, Tao Liu, Jia Jin, Ruoxi Zhang, Chunwei Key Laboratory of Structures Dynamic Behavior and Control of China Ministry of Education Harbin Institute of Technology Harbin 150090 China China Tianchen Engineering Corporation Tianjin 300400 China School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Institute for Infrastructure Engineering University of Western Sydney Sydney NSW 2751 Australia

In this paper, the mechanical property of damaged concrete after impact was investigated. Firstly, the specimen was crushed by using drop hammer impact test machine in order to cause initial damage. Then compression-after-impact tests were carried out to examine and compare the damage responses of the specimens, and some stress-strain curves of the specimens under different damage degrees were obtained. Test parameters, such as the strength grade, height of the fall and drop weight were studied. The damage behaviors of the 24 tested specimens with the acquired UT (ultrasonic test) data were analyzed. The experiment results indicate that using UT to test the damage of concrete is highly sensitive;Concrete elastic modulus and compressive strength after impact are reduced. Brittle fracture of the concrete specimen after impact is remarkable.

关键词： Concretes

来源：评论

学校读者我要写书评

暂无评论

PROPULSIVE EFFICIENCY OF MAN IN THE SEA

引用

Naval Engineers Journal 1966年第1期78卷 17-24页

作者： TAGGART, ROBERT The author graduated from Webb Institute of Naval Architecture in 1942 with a degree of Bachelor of Science in Naval Architecture and Marine Engineering. He has been employed by the Maritime Commission the Naval Research Laboratory the Army Transportation Corps the Bureau of Ships Reed Research Inc. and served as a Naval Officer during World War II. In 1958 he formed Robert Taggart Incorporated. He has been engaged in research and development work for the past twenty years all of which has been related to naval engineering and oceanography. Extensive experience was gained in ship stability and seaworthiness noise shock and vibration of ships model and full scale tests of ship resistance propulsion and maneuverability ship structural behavior at sea and the design and control of unusual ship propulsion systems. Among his publications are reports papers and articles on side launching calculations ship standardization and fuel economy trials maneuvering trials hull form studies development of underwater acoustic facilities noise control of submarines and mine sweepers ambient noise surveys underwater missiles barge and tug design utilization of ships for research the development of ship propulsion systems and the development of propulsion and control systems for the dynamic positioning of ships on the ocean surface. Mr. Taggart is a licensed professional engineer in the District of Columbia and in Virginia. He is a member of the Society of Naval Architects and Marine Engineers the American Society of Naval Engineers the Northeast Coast Institution of Engineers and Shipbuilders the American Institute of Physics the Acoustical Society of America the American Institute of Aeronautics and Astronautics the American Geophysical Union and the Interntional Oceano-graphic Foundation.

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：