检索结果-南通市图书馆

Monitoring of velocity changes based on seismic ambient noise: A brief review and perspective

Earth and Planetary Physics 2020年第5期4卷 532-542页

作者： qing-Yu wang HuaJian Yao University Grenoble Alpes CNRSISTerreGrenobleFrance Laboratory of Seismology and Physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaMengcheng Anhui 233500China

Over the past two decades,the development of the ambient noise cross-correlation technology has spawned the exploration of underground *** addition,ambient noise-based monitoring has emerged because of the feasibility of reconstructing the continuous Green’s *** the physical properties of a subsurface medium by tracking changes in seismic wave velocity that do not depend on the occurrence of earthquakes or the continuity of artificial sources dramatically increases the possibility of researching the evolution of crustal *** this article,we outline some state-of-the-art techniques for noise-based monitoring,including moving-window cross-spectral analysis,the stretching method,dynamic time wrapping,wavelet cross-spectrum analysis,and a combination of these measurement methods,with either a Bayesian least-squares inversion or the Bayesian Markov chain Monte Carlo *** briefly state the principles underlying the different methods and their pros and *** elaborating on some typical noisebased monitoring applications,we show how this technique can be widely applied in different scenarios and adapted to multiples *** list classical applications,such as following earthquake-related co-and postseismic velocity changes,forecasting volcanic eruptions,and tracking external environmental forcing-generated transient *** monitoring cases having different targets at different scales,we point out the applicability of this technology for disaster prediction and early warning of small-scale reservoirs,landslides,and so ***,we conclude with some possible developments of noise-based monitoring at present and summarize some prospective research *** improve the temporal and spatial resolution of passive-source noise monitoring,we propose integrating different methods and seismic *** interdisciplinary collaboration is indispensable for comprehensively interpreting the observed changes.

关键词： ambient noise correlation noise-based monitoring seismic wave velocity changes the evolution of physical properties of the crust

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hot deformation behavior of a near alpha titanium alloy with/without thermal hydrogen processing

引用

Acta Metallurgica Sinica(English Letters) 2010年第2期23卷 106-112页

作者： qing wang Dongli SUN Xiuli HAN Weigong wang School of Materials Science and Engineering Harbin Institute o) Technology Harbin 150001 China

The true stress-true strain curves of Ti-6Al-2Zr-IMO-IV alloy with hydrogen were obtained by hot compression test. The microstructures of the alloy before and after thermo-compression were observed. The apparent activation energies of deformation were calculated for the alloy with and without hydrogen. The behavior and mechanism of deformation for hydrogenated Ti-6A1-2Zr-IMO-IV alloy at high temperature were analyzed. The relationship between hydrogenation time and hydrogen content at 800 ℃ can be expressed as the equation： CH（t）=1.2-1.2exp（-t/120）. The true stress-true strain curves of hot compression for Ti-6Al-2Zr-IMO-IV alloy with hydrogen first move down and then move up as hydrogen content increases. Appropriate hydrogen content can reduce the peak of flow stress to minimal value. The apparent activation energies of deformation of the alloy with 0.47% hydrogen content and without hydrogen were calculated as 140 kJ·mol^-1 and 390 kJ-mol^-1, respectively, at 800 ℃ and at strain rate 8.3×10^4 s^-1. The apparent activation energy of deformation increases when the strain rate enhances from 8.3×10^-4 s^-1 to 8.3×10^-2 s^-1.

关键词： Titanium alloy Thermal hydrogen processing Compression at high temperature Hot deformation behavior Apparent activa- tion energy of deformation Microstructure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fault detection and optimization for networked control systems with uncertain time-varying delay

引用

Journal of Systems Engineering and Electronics 2015年第3期26卷 544-556页

作者： qing wang Zhaolei wang Chaoyang Dong Erzhuo Niu School of Automation Science and Electrical Engineering Beihang University Beijing Aerospace Automatic Control Institute School of Aeronautic Science and Engineering Beihang University Flight Automatic Control Research Institute Aviation Industry Corporation

The observer-based robust fault detection filter design and optimization for networked control systems （NOSs） with uncer- tain time-varying delays are addressed. The NCSs with uncertain time-varying delays are modeled as parameter-uncertain systems by the matrix theory. Based on the model, an observer-based residual generator is constructed and the sufficient condition for the existence of the desired fault detection filter is derived in terms of the linear matrix inequality. Furthermore, a time domain opti- mization approach is proposed to improve the performance of the fault detection system. To prevent the false alarms, a new thresh- old function is established, and the solution of the optimization problem is given by using the singular value decomposition （SVD） of the matrix. A numerical example is provided to illustrate the effectiveness of the proposed approach.

关键词： fault detection networked control systems residual generator time-varying delay time domain optimization approach.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A numerical model study on multi-species harmful algal blooms coupled with background ecological fields

引用

Acta Oceanologica Sinica 2014年第8期33卷 95-105页

作者： wang qing ZHU Liangsheng wang Dongxiao State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences Naval Architecture and Ocean Engineering R & D Center of Guangdong Province South China University of Technology Graduate University of Chinese Academy of Sciences

Based on systematized physical, chemical, and biological modules, a multi-species harmful algal bloom （HAB） model coupled with background ecological fields was established. This model schematically embod-ied that HAB causative algal species and the background ecological system, quantified as total biomass, were significantly different in terms of the chemical and biological processes during a HAB while the inter-action between the two was present. The model also included a competition and interaction mechanism between the HAB algal species or populations. The Droop equation was optimized by considering tempera-ture, salinity, and suspended material impact factors in the parameterization of algal growth rate with the nutrient threshold. Two HAB processes in the springs of 2004 and 2005 were simulated using this model. Both simulation results showed consistent trends with corresponding HAB processes observed in the East China Sea, which indicated the rationality of the model. This study made certain progress in modeling HABs, which has great application potential for HAB diagnosis, prediction, and prevention.

关键词： background ecological fields multi-species harmful algal bloom numerical model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reducible solution to a quaternion tensor equation

引用

Frontiers of Mathematics in China 2020年第5期15卷 1047-1070页

作者： Mengyan XIE qing-Wen wang Department of Mathematics Shanghai UniversityShanghai 200444China

We establish necessary and sufficient conditions for the existence of the reducible solution to the quaternion tensor equation A*N C*NB=C via Einstein product using Moore-Penrose inverse,and present an expression of the reducible solution to the equation when it is ***,to have a general solution,we give the solvability conditions for the quaternion tensor equation A1*N C1*MB1+a1*C2*MB2+A2*NC3*MB2=e,which plays a key role in investigating the reducible solution to A*NC*NB=*** expression of such a solution is also presented when the consistency conditions are *** addition,we show a numerical example to illustrate this result.

关键词： Quaternion tensor quaternion tensor equation Einstein product Moore-Penrose inverse general solution reducible solution

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparison of Two Dripper Line Designs to Assess Cotton Yield,Water Use,and Net Return in Northwest China

引用

Journal of Integrative Agriculture 2012年第11期11卷 1924-1932页

作者： wang ruo-shui WAN Shu-qin KANG Yue-hu LIU Shi-ping Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing 100101 P.R.China University of Chinese Academy of Sciences Beijing 100049 P.R. China

This study aimed to compare the effects of two types of drip irrigation line design on cotton yield, water use, and net returns. The experiments were carried out in the arid region of Xinjiang, Northwest China, during 2009-2010 growing years. The two types of lateral placement are commonly used by the local farmers in the area： double lines （two laterals controlling four rows） and single line designs （one lateral controlling four rows）. The results indicated that less irrigation water was applied by single line compared with double lines design. This implies that more irrigation water could be saved using single line, by reducing the water consumption of cotton. The emergence rates for double lines were 2 and 6% higher than those for single line design in 2009 and 2010. The seed cotton yields for double lines design were 5.76 and 6.41 Mg ha-1 which were 13 and 9% higher than for single line design in 2009 and 2010, respectively. Single lines could however lower the investment cost compared to double lines, which produced 10 and 7% more net income in 2009 and 2010, respectively. By contrast, the double lines was more profitable and suitable for the farmers in Northwest China than single line design.

关键词： drip irrigation lateral layout economic benefit water saving water use efficiency (WUE)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Closed-loop fault detection for full-envelope flight vehicle with measurement delays

引用

Chinese Journal of Aeronautics 2015年第3期28卷 832-844页

作者： wang Zhaolei wang qing Dong Chaoyang Gong Ligang School of Automation Science and Electrical Engineering Beihang University Beijing Aerospace Automatic Control Institute School of Aeronautical Science and Engineering Beihang University

Abstract A closed-loop fault detection problem is investigated for the full-envelope flight vehicle with measurement delays, where the flight dynamics are modeled as a switched system with delayed feedback signals. The mode-dependent observer-based fault detection filters and state estimation feedback controllers are derived by considering the delays＇ impact on the control system and fault detection system simultaneously. Then, considering updating lags of the controllers/filters＇ switching signals which are introduced by the delayed measurement of altitude and Mach number, an asynchronous H analysis method is proposed and the system model is further augmented to be an asynchronously switched time-delay system. Also, the global stability and desired performance of the augmented system are guaranteed by combining the switched delay-dependent Lyapunov Krasovskii functional method with the average dwell time method （ADT）, and the delaydependent existing conditions for the controllers and fault detection filters are obtained in the form of the linear matrix inequalities （LMIs）, Finally, numerical example based on the hypersonic vehicles and highly maneuverable technology （HiMAT） vehicle is given to demonstrate the merits of the proposed method.

关键词： Fault diagnosis Measurement delays Asynchronous switching Full-envelope flight vehicle Closed-loop fault detection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cultivating Erect Milkvetch (Astragalus adsurgens Pall.) (Leguminosae) Improved Soil Properties inLoess Hilly and Gulliesin China

引用

Journal of Integrative Agriculture 2013年第9期12卷 1652-1658页

作者： wang Zhan-bin wang qing-yi Animal Science and Technology School Henan University of Science and Technology

Erect milkvetch （Astragalus adsurgens Pall.）, a leguminous grass, is a major source of fuel and forage, and has an important role in the restoration of the degraded ecosystems in central and northeastern China. The objective of this work was to investigate how erect milkvetch planting would affect the physical and chemical properties of soil in degraded arable lands. Soil samples at the depths of 0-20 and 20-40 cm were collected from erect milkvetch planting fileds at ages of 0, 1, 2 and 3 yr. Changes in soil bulk density, soil porosity, total N and P, organic matter content, available P, hydrolysable N and available K were measured. The results showed that root biomass and above-ground plant biomass were both significantly increased with plantation age. The significant increase in root nodule biomass was not observed in the first two years. However, it was significantly increased after three years. Root growth of erect milkvetch improved soil structure, and hence, decreased soil bulk density and increased soil porosity. Furthermore, the nitrogen fixation by erect milkvetch and return of erect milkvetch plant to soil increased the soil total N, hydrolysable N and organic matter content of the soil. Low concentrations of P in the soil with erect milkvetch planting could be ascribed to high plant uptakes and possibly to high sequestrations of P in plant biomass. Concentrations of K significantly increased during the first two years of erect milkvetch planting. The high accumulation of K under erect milkvetch cultivation in the first two years could partly be attributed to low plant uptake, and partly to relatively quick recycling within plant-soil systems. Three years after erect milkvetch plantingr, K accumulation at 0-20 cm soil layer was significantly lower than that from non-vegetated field sites, which could be attributed to high plant uptake. These parameters, except for soil bulk density, were all decreased with increasing soil depth. Soil total N, organic matt

关键词： Asuagalus adsurgens Pall. soil properties plantation age loess hills and gullies

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Boundary Contour Method for Half-Plane Piezoelectric Media

引用

上海交通大学学报 2004年第z2期38卷 176-181页

作者： wang Guoqing wang qing LIU Zhengxing DING Haojiang Department of Engineering Mechanics Shanghai Jiaotong Univ. Shanghai200030 China Department of Engineering Mechanics Shanghai Jiaotong Univ. Shanghai200030 China Department of Engineering Mechanics Shanghai Jiaotong Univ. Shanghai200030 China Department of Civil Engineering Zhejiang Univ. Hangzhou310027 China

This paper presents a further development of the Boundary Contour Method (BCM) for half-plane piezoelectric media. Firstly, the divergence free property of the integrand of the half-plane piezoelectric boundary element is proven. Secondly, the boundary contour method formulation is derived and potential functions are obtained by introducing linear shape functions and Green's functions[1] for half-plane piezoelectric media. Finally, numerical solutions for illustrative example are compared with exact ones and that of conventional boundary element method (BEM) ones. The numerical results of BCM coincide very well with exact solution, and the feasibility and efficiency of the method are verified.

关键词： boundary contour method piezoelectricity half-plane shape function

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Weighted Moore-Penrose Inverses and Weighted Core Inverses in Rings with Involution

引用

Chinese Annals of Mathematics,Series B 2021年第4期42卷 613-624页

作者： Huihui ZHU qing-Wen wang Department of Mathematics Shanghai UniversityShanghai 200444China School of Mathematics Hefei University of TechnologyHefei 230009China

In this paper,the authors derive the existence criteria and the formulae of the weighted Moore-Penrose inverse,the e-core inverse and the f-dual core inverse in ***,new characterizations between weighted Moore-Penrose... 详细信息

关键词： Weighted Moore-Penrose inverses One-sided inverses along an element Inverses along an element e-Core inverses f-Dual core inverses

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：