检索结果-南通市图书馆

Measurement of ice flow velocities from GPS positions logged by short-period seismographs in East Antarctica

Science China Earth Sciences 2021年第8期64卷 1381-1389页

作者： Lei FU Jingxue GUO xiaofei CHEN Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology Southern University of Science and TechnologyShenzhen 518055China Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Key Laboratory for Polar Science MNRPolar Research Institute of ChinaShanghai 200136China

The ice flow velocity is a basic feature of glaciers and ice sheets. Measuring ice flow velocities is very important for estimating the mass balance of ice sheets in the Arctic and Antarctic. Traditional methods for measuring ice flow velocity include the use of stakes, snow pits and on-site geodetic GPS and remote sensing measurement methods. Geodetic GPS measurements have high accuracy, but geodetic GPS monitoring points only sparsely cover the Antarctic ice sheets. Moreover, the resolution and accuracy of ice flow velocities based on remote sensing measurements are low. Although the accuracy of the location data recorded by the navigation-grade GPS receivers embedded in short-period seismographs is not as good as that of geodetic GPS,the ice flow velocity can be accurately measured by these navigation-grade GPS data collected over a sufficiently long period. In this paper, navigation-grade GPS location data obtained by passive seismic observations during the 36 th Chinese National Antarctic Research Expedition were used to accurately track the movement characteristics of the ice sheet in the Larsemann Hills of East Antarctica and the Taishan Station area. The results showed that the ice sheet in the two study areas is basically moving northwestward with an average ice flow velocity of approximately 1 m mon-1. The results in the Taishan Station area are basically consistent with the geodetic GPS results, indicating that it is feasible to use the embedded GPS location data from shortperiod seismographs to track the movement characteristics of ice sheets. The ice flow characteristics in the Larsemann Hills are more complex. The measured ice flow velocities in the Larsemann Hills with a resolution of 200 m help to understand its characteristics. In summary, the ice flow velocities derived from GPS location data are of great significance for studying ice sheet dynamics and glacier mass balance and for evaluating the systematic errors caused by ice sheet movements in s

关键词： Short-period seismograph Antarctic ice sheet Ice flow velocity GPS

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

Decadal Changes in Interannual Dependence of the Bay of Bengal Summer Monsoon Onset on ENSO Modulated by the Pacific Decadal Oscillation

引用

Advances in Atmospheric Sciences 2019年第12期36卷 1404-1416页

作者： xiaofei WU Jiangyu MAO School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Joint Laboratory of Climate and Environment Change Chengdu University of Information TechnologyChengdu 610225China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Interannual variations of the Bay of Bengal summer monsoon (BOBSM) onset in association with El Ni-o-Southern Oscillation (ENSO) are reexamined using NCEP1, JRA-55 and ERA20C atmospheric and Hadley sea surface temperature (SST) reanalysis datasets over the period 1900-2017. Decadal changes exist in the dependence of the BOBSM onset on ENSO, varying with the Pacific Decadal Oscillation (PDO). A higher correlation between the BOBSM onset and ENSO arises during the warm PDO epochs, with distinct late (early) onsets following El Ni-o (La Ni-a) events. In contrast, less significant correlations occur during the cold PDO epochs. The mechanism for the PDO modulating the ENSO-BOBSM onset relationship is through the variations in SST anomaly (SSTA) patterns. During the warm PDO epochs, the superimpositions of the PDO-related and ENSO-related SSTAs lead to the SSTA distribution of an El Ni-o (La Ni-a) event exhibiting significant positive (negative) SSTAs over the tropical central-eastern Pacific and Indian Ocean along with negative (positive) SSTAs, especially over the tropical western Pacific (TWP), forming a strong zonal interoceanic SSTA gradient between the TWP and tropical Indian Ocean. Significant anomalous lower tropospheric easterlies (westerlies) together with upper-tropospheric westerlies (easterlies) are thus induced over the BOB, favoring an abnormally late (early) BOBSM onset. During the cold PDO epochs, however, the superimpositions of PDO-related SSTAs with El Ni-o-related (La Ni-a-related) SSTAs lead to insignificant SSTAs over the TWP and a weak zonal SSTA gradient, without distinct circulation anomalies over the BOB favoring early or late BOBSM onsets.

关键词： decadal change Bay of Bengal summer monsoon onset ENSO Pacific Decadal Oscillation

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 Generalized Propagator Algorithm for Localization of Non-circular Sources Using Arbitrary Array Geometry

引用

Transactions of Nanjing University of Aeronautics and Astronautics 2019年第2期36卷 339-351页

作者： CAO Renzheng ZHANG xiaofei The 28th Research Institute China Electronics Technology Group CorporationNanjing 210007P.R.China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China

A propagator-based algorithm for direction of arrival(DOA)estimation of noncoherent one-dimensional(1-D)non-circular sources is presented such as binary phase shift keying(BPSK)and amplitude modulation(AM).The algorithm achieves DOA estimation through searching a 1-D spectrum,which is newly formed on the basis of the rank reduction criterion,and works well without knowledge of the non-circular *** then,a search-free implementation of the algorithm is also developed by using the polynomial rooting *** to the non-circular property,the algorithm can virtually enlarge the array aperture,thus significantly improving its estimation accuracy and enabling it to handle more sources than the number of ***,the algorithm requires no rotational invariance,so it can be applied to arbitrary array geometry and dispense with the high-complexity procedure of the eigen-decomposition of the correlation sample ***,numerical simulations verify the performance and effectiveness of the proposed algorithm.

关键词： direction of arrival(DOA) subspace method rank reduction criterion propagator non-circular source

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

Tensile and Fatigue Properties of Free-Standing Cu Foils

引用

Journal of Materials Science & Technology 2009年第6期25卷 721-726页

作者： Caiyun Dai xiaofei Zhu Guangping Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Tensile and fatigue properties of free-standing as-rolled Cu foils were investigated by means of uniaxial tensile and dynamic bending tests. A special testing system was established to evaluate fatigue behavior of a microscale material subjected to dynamic bending load. The experimental results show that the yield strength increases, but the fracturestrain and fatigue resistance decrease with decreasing foil thickness. Deformation and fatigue damage behavior was characterized. The size effect on tensile and fatigue properties of the Cu foils are evaluated to get further understanding of the mechanical behavior of the micrometer-scale metallic materials.

关键词： Cu foils Mechanical properties Size effect

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

Targeting ubiquitin signaling for cancer immunotherapy

引用

Signal Transduction and Targeted Therapy 2021年第2期6卷 372-386页

作者： xiaofei Zhou Shao-Cong Sun Department of Immunology The Unvrsity of Texas MD Anderson Cancer Center7455 Fannin SteetBox 902HoustonTX 77030USA The University of Texas Graduate School of Biomedical Sciences HoustonTX 77030USA

Cancer immunotherapy has become an attractive approach of cancer treatment with tremendous success in treating various advanced *** development and clinical application of immune checkpoint inhibitors represent one of the most extraordinary accomplishments in cancer *** addition,considerable progress is being made in understanding the mechanism of antitumor immunity and characterizing novel targets for developing additional therapeutic *** active area of investigation is protein ubiquitination,a post-translational mechanism of protein modifcation that regulates the function of diverse immune cells in antitumor *** studies suggest that E3 ubiquitin ligases and deubiquitinases form a family of potential targets to be exploited for enhancing antitumor immunity in cancer immunotherapy.

关键词： ubiquitin immunotherapy immunity

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

Fast multi-parameter estimation and localization for MIMO radar

引用

Journal of Systems Engineering and Electronics 2015年第3期26卷 486-492页

作者： Lingyun Xu xiaofei Zhang Miao Yu College of Science Nanjing University of Aeronautics and Astronautics Nanjing Telecommunication Technology Institute

This paper addresses the problem of four-dimensional angle and Doppler frequency estimation for bistatic multiple-input multiple-output （MIMO） radar with arbitrary arrays in spatial co- lored noise. A novel method for joint estimation of Doppler fre- quency, two-dimensional （2D） direction of departure and 2D direc- tion of arrival based on the propagator method （PM） for arbitrary arrays is discussed. A special matrix is constructed to eliminate the influence of spatial colored noise. The four-dimensional （4D） angle and Doppler frequency are extracted from the matrix and the three- dimensional （3D） coordinates of the targets are then calculated on the basis of these angles. The proposed algorithm provides a lower computational complexity and has a parameter estimation very close to that of the ESPRIT algorithm and the DOA-matrix al- gorithm in the high signal to noise ratio and the Cramer-Rao bound （CRB） is given. Furthermore, multi-dimensional parameters can be automatically paired by this algorithm to avoid performance degra- dation resulting from wrong pairing. Simulation results demonstrate the effectiveness of the proposed method.

关键词： four-dimensional (4D) angle estimation Doppler frequency estimation propagator method (PM) multiple-input multiple-output (MIMO) radar arbitrary array spatial colored noise.

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

Inversion of near-field waveform data for earthquake source rupture process(Ⅱ):Inversion of Chi Chi earthquake source,20 September,1999,Taiwan

引用

Science China Earth Sciences 2006年第3期49卷 272-282页

作者： ZHOU Shiyong CHEN xiaofei Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China

The new inversion algorithm developed based on the recent progress in thenonlinear programming study by us is used to invert the earthquake source process of Chi Chiearthquake M_w7.6, 20 Semptember,1999, Taiwan. A curve fault model is constructed in our inversionto make the fault model close to the real rupturing fault to reduce the influence from thediscrepancy between the constructed fault model and the real rupturing fault. The results show that(1) the rupture process of the Chi Chi earthquake source lasted about 32 seconds and the mainfaulting occurred between 6th to 21st second after the start of the ruptures and the high slip areawere mainly located at the northern segment of the fault. (2) The slip was dominated by thrustfaulting. The average rake angle was 64.5°, which was very consistent with those inverted by USGS,Harvard and CWB (Central Weather Bureau of Taiwan). The amount of the moment inverted in this paperwas 7.76x10^(20) NM, which was a slightly bigger than those inverted by USGS and Harvard. (3) Aclear nucleation step existed in the source faulting process and it lasted about 6 seconds. Themoment release rate accelerated obviously at the end of the nucleation step. The faulting startedfrom the southern segment and mainly occurred at the northern segment after 10 seconds. At the endof this paper, we analyzed the reliability of the inversion result via comparing with the GPSobservations and discussed its scientific signification.

关键词： Chi Chi earthquake, source rupture process, waveform inversion, near-source data, source mechanism.

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

Bending Deformation of Multilayered One-Dimensional Quasicrystal Nanoplates Based on the Modified Couple Stress Theory

引用

Acta Mechanica Solida Sinica 2019年第6期32卷 785-802页

作者： xiaofei Li Junhong Guo Tuoya Sun Department of Mechanics Inner Mongolia University of TechnologyHohhot 010051China

The modified couple stress theory has been applied in many nanomaterials except for *** this paper,the modified couple stress theory is firstly adopted to analyze the static bending deformation of multilayered one-dimensional(ID)hexagonal quasicrystal(QC)nanoplates under surface *** general solutions for the extended displacement and traction vectors in a simply supported and homogeneous QC nanoplate are derived by solving an eigenvalue problem reduced from the governing *** the propagator matrix method,the analytical solutions of multilayered ID QC nanoplates are then obtained by assuming that the layer interfaces are *** examples for some kinds of nanoplates made up of QC and crystal(BaTiOa)are provided to illustrate the effects of the material length parameter,the number of layers and the stacking sequence of nanoplates on the phonon and phason fields,which is helpful for the application of QCs to surface coating and solar energy selective absorber.

关键词： Quasicrystals(QCs) Nanoplate Layered structure Modified couple stress Analytical 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

Frequency-Bessel multi-mode surface wave tomography utilizing microseisms excited by energetic typhoons

引用

Science China Earth Sciences 2024年第11期67卷 3436-3447页

作者： Xuping FENG Yingjie XIA xiaofei CHEN Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology Southern University of Science and TechnologyShenzhen 518055China Guangdong Province Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and TechnologyShenzhen 518055China College of Geophysics Chengdu University of TechnologyChengdu 610059China Institute of Risk Analysis Prediction and ManagementSouthern University of Science and TechnologyShenzhen 518055China

The recently developed Frequency-Bessel(F-J) transform array technique has significantly advanced multi-mode surface wave tomography, providing precise constraints on shear wave velocity(V_(S)) models of the crust and uppermost *** technique has primarily focused on extracting inter-station surface waves from ambient noise cross-correlation. Energetic typhoons generate abundant surface wave signals, prompting growing interest in utilizing these signals to investigate subsurface structures. This study explores the feasibility and application of using microseisms excited by strong typhoons for F-J transform surface wave tomography. By analyzing microseisms recorded by a broadband seismic array in Mongolia during energetic typhoons, we observed multi-mode surface waves with high signal-to-noise ratios. Our analysis revealed that the sources of these waves closely correspond to typhoon tracks, confirming that they were primarily excited by typhoons. We successfully extracted multi-mode dispersion curves for imaging the V_(S) structure beneath the array using the F-J transform. Additionally, we derived multi-mode dispersion curves from a two-year noise dataset recorded by the same array, which were also used to invert for the V_(S) structure. Comparison of V_(S) models derived from typhoon-induced microseisms and the two-year noise dataset showed negligible differences within the depth range of 0–140 km. Our findings demonstrate the potential value of microseisms generated by energetic typhoons in precisely probing the V_(S)structure of the crust and uppermost mantle.

关键词： Multi-mode surface wave tomography Typhoon-excited microseisms Frequency-Bessel transform Ambient noise cross-correlation Crustal and uppermost mantle structure

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

FunctionFlow:coordinating parallel tasks

引用

Frontiers of Computer Science 2019年第1期13卷 73-85页

作者： Xuepeng FAN xiaofei LIAO Hai JIN Services Computing Technology and System Lab (SCTS)&Cluster and Grid Computing Lab (CGCL) School of Computer Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China

With the growing allel programming,nowadays popularity of task-based partask-parallel programming libraries and languages are still with limited support for coordinating parallel *** limitation forces programmers to use additional independent components to coordinate the parallel tasks -the components can be third-party libraries or additional components in the same programming library or ***,mixing tasks and coordination components increase the difficulty of task-based programming,and blind schedulers for understanding tasks'dependencies. In this paper,we propose a task-based parallel programming library,Function Flow,which coordinates tasks in the purpose of avoiding additional independent coordination ***,we use dependency expression to represent ubiquitous tasks'*** key idea behind dependency expression is to use && for both task's termination and Ⅱ for any task termination,along with the combination of dependency ***,as runtime support,we use a lightweight representation for dependency expression. Also,we use suspended-task queue to schedule tasks that still have prerequisites to run. Finally,we demonstrate Function Flow's effectiveness in two aspects,case study about implementing popular parallel patterns with FunctionFIow,and performance comparision with state-of-the-art practice,*** demonstration shows that FunctionFIow can generally coordinate parallel tasks without involving additional components,along with comparable performance with TBB.

关键词： task parallel programming tasks dependency FunctionFlow coordination patterns

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

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：