中国科学院机构知识库网格系统: 检索

CYGNSS土壤盐分反演方法研究:以黄河三角洲为例 期刊论文 OAI收割
遥感学报, 2023, 卷号: 27, 期号: 2, 页码: 351
作者: 王俊栋; 孙志刚; 杨婷; 朱康莹; 邵长秀

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remote sensing soil salinity CYGNSS the bistatic radar equation dielectric constant Yellow River Delta 遥感土壤盐分 CYGNSS 双基雷达方程介电常数黄河三角洲

Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2021
作者: HXMT

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black hole physics Low Mass X-ray Binaries accretion accretion discs stars: individual (MAXI J1820+070) Astrophysics - High Energy Astrophysical Phenomena Abstract: We present high-speed optical photometry from SAAO and SALT on the black hole LMXB MAXI J1820+070 (ASSASN-18ey), some of it simultaneous with NICER, Swift and Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations (QPOs) that move to higher frequencies as the outburst progresses, tracking both the frequency and evolution of similar X-ray QPOs previously reported. Correlated X-ray/optical data reveal a complex pattern of lags, including an anti-correlation and a sub-second lag that evolve over the first few weeks of outburst. They also show correlated components separated by a lag equal to the QPO period roughly centered on zero lag, implying that the inter-band variability is strongly and consistently affected by these QPOs at a constant phase lag of roughly ±Ю The synchronisation of X-ray and optical QPOs indicates that they must be produced in regions physically very close to each other we thus propose that they can be explained by a precessing jet model, based on analogies with V404 Cyg and MAXI J1348-630.

The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition 期刊论文 OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 494, 页码: 1865-1870
作者: HXMT

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stars: magnetic field stars: neutron pulsars: general Astrophysics - High Energy Astrophysical Phenomena Abstract: In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n of PSR B0540-69 changes from n = 2.12 to 0.03 and then keeps this value for about five years before rising to n = 0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the increasing dipole magnetic field of PSR B0540-69. We suggest that the field increase may result from some instabilities within the pulsar core that enhance the poloidal component at the price of toroidal component of the magnetic field. The increasing dipole magnetic field will result in the X-ray brightening of the PWN. We fit the PWN X-ray light curve by two models: one assumes a constant magnetic field within the PWN during the brightening and the other assumes an enhanced magnetic field proportional to the energy density of the PWN. It appears that the two models fit the data well, though the later model seems to fit the data a bit better. This provides marginal observational evidence that magnetic field in the PWN is generated by the termination shock. Future high-quality and high-cadence data are required to draw a solid conclusion.

Experimental study of methane hydrate dissociation in porous media with different thermal conductivities 期刊论文 OAI收割
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 2019, 卷号: 144, 页码: 10
作者: Li, Xiao-Yan; Wang, Yi; Li, Xiao-Sen; Zhang, Yu; Chen, Zhao-Yang

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收藏 | 浏览/下载：29/0 | 提交时间：2020/10/29

Hydration dissociation Thermal conductivity Depressurization Heat transfer rate The overall rate constant

Constant cyclotron line energy in Hercules X-1 - Joint Insight-HXMT and NuSTAR observations 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2019, 卷号: 23, 页码: 29-32
作者: HXMT

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Stars: neutron star Pulsars: binary(Her X-1) X-rays: stars Astrophysics - High Energy Astrophysical Phenomena Abstract: The long-term evolution of the centroid energy of the CRSF in Her X-1 is still a mystery. We report a new measurement from a campaign between Insight-HXMT and NuSTAR performed in February 2018. Generally, the two satellites show well consistent results of timing and spectral properties. The joint spectral analysis confirms that the previously observed long decay phase has ended, and that the line energy instead keeps constant around 37.5 keV after flux correction.

Timing analysis of Swift J1658.2-4242's outburst in 2018 with Insight-HXMT, NICER and AstroSat 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2019, 卷号: 24, 页码: 30-40
作者: HXMT

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Accretion accretion disks Black hole physics X-rays: binaries: Swift J1658.2-4242 Astrophysics - High Energy Astrophysical Phenomena Abstract: We present the observational results from a detailed timing analysis of the black hole candidate Swift J1658.2-4242 during its 2018 outburst with the observations of Hard X-ray Modulation Telescope (Insight-HXMT), Neutron Star Interior Composition Explorer (NICER) and AstroSat in 0.1-250 keV. The evolution of intensity, hardness and integrated fractional root mean square (rms) observed by Insight-HXMT and NICER are presented in this paper. Type-C quasi-periodic oscillations (QPOs) observed by NICER (0.8-3.5 Hz) and Insight-HXMT (1-1.6 Hz) are also reported in this work. The features of the QPOs are analyzed with an energy range of 0.5-50 keV. The relations between QPO frequency and other characteristics such as intensity, hardness and QPO rms are carefully studied. The timing and spectral properties indicate that Swift J1658.2-4242 is a black hole binary system. Besides, the rms spectra of the source calculated from the simultaneous observation of Insight-HXMT, NICER and AstroSat support the Lense-Thirring origin of the QPOs. The relation between QPO phase lag and the centroid frequency of Swift J1658.2-4242 reveals a near zero constant when < 4Hz and a soft phase lag at 6.68 Hz. This independence follows the same trend as the high inclination galactic black hole binaries such as MAXI J1659-152.

Gas-phase hydration of glyoxylic acid: Kinetics and atmospheric implications 期刊论文 OAI收割
CHEMOSPHERE, 2017, 卷号: 186, 页码: 430-437
作者: Liu, Ling; Zhang, Xiuhui; Li, Zesheng; Zhang, Yunhong; Ge, Maofa

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Glyoxylic Acid Hydration In The Atmosphere Catalyzed By Atmospheric Common Substances Mechanism And Kinetics Effective Rate Constant Coastal And Polluted Regions

A physical self-similarity law describing the accelerated failure behavior of rocks 期刊论文 OAI收割
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2017, 卷号: 60, 期号: 5, 页码: 1746-1760
作者: Yang Bai-Cun; Qin Si-Qing; Xue Lei; Chen Hong-Ran; Wu Xiao-Wa

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Equivalent Stress Accelerated Failure Behavior Of Rock Physical Self-similarity The Constant 1. 48 Brittle Failure Of Multiple Locked Patches

Spatial and temporal variations of the fine-structure constant in the Finslerian universe 期刊论文 OAI收割
CHINESE PHYSICS C, 2017, 卷号: 41, 期号: 6, 页码: 65102
作者: Li, X; Lin, HN; Li, X (reprint author), Chongqing Univ, Dept Phys, Chongqing 401331, Peoples R China.; Li, X (reprint author), Chinese Acad Sci, Inst Theoret Phys, State Key Lab Theoret Phys, Beijing 100190, Peoples R China.

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收藏 | 浏览/下载：21/0 | 提交时间：2017/12/21

Finsler Spacetime Fine-structure Constant Anisotropy Of The Universe

Deep subwavelength electromagnetic transparence through dual metallic gratings with ultranarrow slits (EI CONFERENCE) 会议论文 OAI收割
2012 International Workshop on Metamaterials, Meta 2012, October 8, 2012 - October 10, 2012, Nanjing, China
作者: Liu Z.; Li S.; Li F.

收藏 | 浏览/下载：32/0 | 提交时间：2013/03/25

We study the transmission response of microwaves through two identical metallic plates perforated with periodical ultranarrow slits. The experimental and numerical transmission spectra consistently display a striking transmission peak at wavelength much larger than any characteristic length of the microstructure (e.g. about 20-fold of the lattice constant) which can not be directly interpreted by the existing mechanisms. Both the LC-circuit-based microscopic picture and the effective-medium-based macroscopic model are established to capture the essential physics behind such unexpected resonance at the deep subwavelength scale. 2012 IEEE.