中国科学院机构知识库网格系统: 检索

A novel Greenness and Water Content Composite Index (GWCCI) for soybean mapping from single remotely sensed multispectral images 期刊论文 OAI收割
REMOTE SENSING OF ENVIRONMENT, 2023, 卷号: 295, 页码: 16
作者: Chen, Hui; Li, Huapeng; Liu, Zhao; Zhang, Ce; Zhang, Shuqing

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收藏 | 浏览/下载：41/0 | 提交时间：2023/10/09

Soybean mapping methods Automatic crop mapping Sentinel-2 Short-wave infrared (SWIR) Normalized difference vegetation index (NDVI)

Adaptive parameter-related implementation of the free surface in elastic anisotropic full-waveform modeling 期刊论文 OAI收割
JOURNAL OF APPLIED GEOPHYSICS, 2022, 卷号: 206, 页码: 17
作者: Zhou, Xuhui; Cao, Jian; Wang, Guangfu; Sun, Jianfang; Huo, Shoudong

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收藏 | 浏览/下载：19/0 | 提交时间：2023/04/03

2D FD modeling Free surface boundary Finite difference methods Numerical modeling

Three-dimensional anisotropy modelling and simulation of gas hydrate borehole-to-surface responses 期刊论文 OAI收割
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING, 2022, 卷号: 106, 页码: 19
作者: Omisore, Busayo Oreoluwa; Fayemi, Olalekan; Brantson, Eric Thompson; Jin, Sheng; Ansah, Ebenezer

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收藏 | 浏览/下载：23/0 | 提交时间：2023/04/03

Anisotropy Controlled source electromagnetic Electromagnetic methods Gas hydrate Finite difference frequency domain

A Nonbalanced Staggered-Grid FDTD Scheme for the First-Order Elastic-Wave Extrapolation and Reverse-Time Migration 期刊论文 OAI收割
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, 2022, 卷号: 15, 页码: 4772-4781
作者: Liang, Wenquan; Chen, Guoxin; Wang, Yanfei; Cao, Jingjie; Chen, Jinxin

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收藏 | 浏览/下载：51/0 | 提交时间：2022/07/18

Mathematical models Finite difference methods Dispersion Propagation Time-domain analysis Imaging Finite element analysis Elastic waves finite-difference methods geophysics computing reverse-time migration (RTM)

An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者: HXMT

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收藏 | 浏览/下载：59/0 | 提交时间：2022/02/08

accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.

Discrete-element investigation of granular debris-flow runup against slit structures 会议论文 OAI收割
Golden, CO, June 10, 2019 - June 13, 2019
作者: Du, Junhan; Zhou, Gordon G.D.

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收藏 | 浏览/下载：39/0 | 提交时间：2020/03/10

Dams Finite difference method Granular materials Hazards Numerical methods

Parametric Amplification in a Superconducting Microstrip Transmission Line 期刊论文 OAI收割
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 2016, 卷号: 26, 期号: 6
作者: Shan, Wenlei; Sekimoto, Yutaro; Noguchi, Takashi

收藏 | 浏览/下载：30/0 | 提交时间：2016/09/27

Finite-difference methods microstrip parametric amplifiers (PAs) shock waves superconducting transmission lines

Frequency multiscale full-waveform velocity inversion 期刊论文 OAI收割
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2015, 卷号: 58, 期号: 1, 页码: 216-228
作者: Zhang WenSheng; Luo Jia; Teng JiWen

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收藏 | 浏览/下载：31/0 | 提交时间：2021/01/14

ABSORBING BOUNDARY-CONDITIONS SEISMIC-REFLECTION DATA FINITE-FREQUENCY DIFFRACTION TOMOGRAPHY ELASTIC INVERSION NEWTON METHODS GAUSS-NEWTON DOMAIN MEDIA MINIMIZATION Acoustic wave equation Frequency multiscale Time domain Full-waveform inversion Velocity BFGS Marmousi model Finite-difference method MPI parallel

Features extraction and matching of teeth image based on the SIFT algorithm (EI CONFERENCE) 会议论文 OAI收割
2012 2nd International Conference on Computer Application and System Modeling, ICCASM 2012, July 27, 2012 - July 29, 2012, Shenyang, China
作者: Wang X.; Wang X.; Wang X.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

Using of SIFT algorithm in the image of teeth model can detect the features of the teeth image effectively. In this approach first search over all scales and image locations by using a difference-of-Gaussian function to identify potential interest points that are invariant to scale and orientation. Second select keypoints based on measures of their stability and a detailed model is fit to determine location and scale at each candidate location. Third assign one or more orientations to each keypoint location based on local image gradient directions. Last measure the local image gradients at the selected scale in the region around each keypoint. And then use the KNN algorithm to match the features. Through lots of experiments and comparing with other feature extraction methods this method can detect the features of the teeth model effectively and offer some available parameters for 3D reconstruction of the teeth model. the authors.

A STABILIZED EQUAL-ORDER FINITE VOLUME METHOD FOR THE STOKES EQUATIONS 期刊论文 OAI收割
JOURNAL OF COMPUTATIONAL MATHEMATICS, 2012, 卷号: 30, 期号: 6, 页码: 615-628
作者: Tian Wanfu; Song Liqiu; Li Yonghai

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收藏 | 浏览/下载：24/0 | 提交时间：2021/02/02

GENERALIZED DIFFERENCE-METHODS ELEMENT METHODS INCOMPRESSIBLE-FLOW COVOLUME METHOD Stokes equations Equal-order finite element pair Finite volume method Error estimate