期刊文献+
共找到2,845篇文章
< 1 2 143 >
每页显示 20 50 100
Rapid source inversions of the 2023 SE Türkiye earthquakes with teleseismic and strong-motion data 被引量:1
1
作者 Chenyu Xu Yong Zhang +4 位作者 Sibo Hua Xu Zhang Lisheng Xu Yuntai Chen Tuncay Taymaz 《Earthquake Science》 2023年第4期316-327,共12页
We conducted rapid inversions of rupture process for the 2023 earthquake doublet occurred in SE Türkiye,the first with a magnitude of M_(W)7.8 and the second with a magnitude of M_(W)7.6,using teleseismic and str... We conducted rapid inversions of rupture process for the 2023 earthquake doublet occurred in SE Türkiye,the first with a magnitude of M_(W)7.8 and the second with a magnitude of M_(W)7.6,using teleseismic and strong-motion data.The teleseismic rupture models of the both events were obtained approximately 88 and 55 minutes after their occurrences,respectively.The rupture models indicated that the first event was an asymmetric bilateral event with ruptures mainly propagating to the northeast,while the second one was a unilateral event with ruptures propagating to the west.This information could be useful in locating the meizoseismal areas.Compared with teleseismic models,the strong-motion models showed relatively higher resolution.A noticeable difference was found for the M_(W)7.6 earthquake,for which the strong-motion models shows a bilateral event,rather than a unilateral event,but the dominant rupture direction is still westward.Nevertheless,all strong-motion models are consistent with the teleseismic models in terms of magnitudes,durations,and dominant rupture directions.This suggests that both teleseismic and strong-motion data can be used for fast determination of major source characteristics.In contrast,the strong-motion data would be preferable in future emergency responses since they are recorded earlier and have a better resolution ability on the source ruptures. 展开更多
关键词 the 2023 earthquake doublet in SE Türkiye fast source inversion teleseismic inversion strong-motion inversion
下载PDF
Duplicate Form of the Generalized Carlitz Inversions and Summation Formulae
2
作者 Qiaoying Dong 《Journal of Applied Mathematics and Physics》 2019年第4期900-911,共12页
The duplicate form of the generalized Gould-Hsu inversions has been obtained by Shi and Zhang. In this paper, we present a simple proof of this duplicate form. With the same method, we construct the duplicate form of ... The duplicate form of the generalized Gould-Hsu inversions has been obtained by Shi and Zhang. In this paper, we present a simple proof of this duplicate form. With the same method, we construct the duplicate form of the generalized Carlitz inversions. Using this duplicate form, we obtain several terminating basic hypergeometric identities and some limiting cases. 展开更多
关键词 DUPLICATE inversions GENERALIZED Gould-Hsu inversions GENERALIZED Carlitz inversions
下载PDF
Temperature Inversions,Meteorological Variables and Air Pollutants and Their Influence on Acute Respiratory Disease in the Guadalajara Metropolitan Zone,Jalisco,Mexico
3
作者 Hermes U.Ramirez-Sanchez Mario E.García-Guadalupe +4 位作者 Hector H.Ulloa-Godinez Angel R.Meulenert-Pena Omar Garcia-Concepcion Jaime Alcala Gutierrez Sarahi J.Lizarraga Brito 《Journal of Environmental Protection》 2013年第8期142-153,共12页
The presence of temperature inversions (TI), concentration of air pollutants (AP) and meteorological variables (MV) affect the welfare of the population, creating public health problems (acute respiratory diseases ARD... The presence of temperature inversions (TI), concentration of air pollutants (AP) and meteorological variables (MV) affect the welfare of the population, creating public health problems (acute respiratory diseases ARDs, among others). The Guadalajara Metropolitan Zone (GMZ) experiences high levels of air pollution, which associated with the presence of temperature inversions and meteorological variations is conducive to the incidence of ARDs in children. The aim of this work is to evaluate the TI, MV, AP and their influence on the ARDs in children under five years in the GMZ from 2003 to 2007. In this period, the moderate and strong TI are the most frequent presenting from November to May. The AP shows a variable behavior during the year and between years, with the highest concentration of particles less than 10 microns (PM10), followed by ozone (O3), nitrogen dioxide (NO2), nitrogen oxides (NOX), carbon monoxide (CO) and sulfur dioxide (SO2), the most affected areas are the southeast of the GMZ. Annual arithmetic mean is 213,510 ± 41,209 ARDs consultations. The most important diseases are acute respiratory infections (98.0%), followed by pneumonia and bronchopneumonia (1.1%), asthma and status asthmaticus (0.5%) and streptococcal pharyngitis and tonsillitis (0.4%). Months with most inquiries were from October to March, mainly in the southeast, south and center of the city, coinciding with high levels of AP. Statistical analysis shows that the TI have significant correlation with ARDs in three years, temperature (Temp) in two, relative humidity (RH) in two, wind speed (WS) in three, wind direction (WD) in two, while that air pollutants NOX and NO2 showed significant correlation with ARDs throughout the period. CO and SO2 showed significance in two years, while the PM10 and O3 in one. 展开更多
关键词 Temperature inversions Meteorological Variables Air Pollutants Acute Respiratory Diseases
下载PDF
Low-Level Temperature Inversions and Their Effect on Aerosol Condensation Nuclei Concentrations under Different Large-Scale Synoptic Circulations 被引量:13
4
作者 LI Jun CHEN Hongbin +3 位作者 Zhanqing LI WANG Pucai Maureen CRIBB FAN Xuehua 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第7期898-908,共11页
Knowledge of the statistical characteristics of inversions and their effects on aerosols under different large-scale synoptic circulations is important for studying and modeling the diffusion of pollutants in the boun... Knowledge of the statistical characteristics of inversions and their effects on aerosols under different large-scale synoptic circulations is important for studying and modeling the diffusion of pollutants in the boundary layer. Based on results gen- erated using the self-organizing map (SOM) weather classification method, this study compares the statistical characteristics of surface-based inversions (SBIs) and elevated inversions (EIs), and quantitatively evaluates the effect of SBIs on aerosol condensation nuclei (CN) concentrations and the relationship between temperature gradients and aerosols for six prevailing synoptic patterns over the the Southern Great Plains (SGP) site during 2001-10. Large-scale synoptic patterns strongly influ- ence the statistical characteristics of inversions and the accumulation of aerosols in the low-level atmosphere. The activity, frequency, intensity, and vertical distribution of inversions are significantly different among these synoptic patterns. The verti- cal distribution of inversions varies diurnally and is significantly different among the different synoptic patterns. Anticyclonic patterns affect the accumulation of aerosols near the ground more strongly than cyclonic patterns. Mean aerosol CN con- centrations increase during SBIs compared to no inversion cases by 16.1%, 22.6%, 24.5%, 58.7%, 29.8% and 23.7% for the six synoptic patterns. This study confirms that there is a positive correlation between temperature gradients and aerosol CN concentrations near the ground at night under similar large-scale synoptic patterns. The relationship is different for different synoptic patterns and can be described by linear functions. These findings suggest that large-scale synoptic patterns change the static stability of the atmosphere and inversions in the lower atmosphere, thereby influencing the diffusion of aerosols near the ground. 展开更多
关键词 temperature inversion AEROSOL condensation nuclei large-scale synoptic pattern statistical characteristics
下载PDF
Analysis of Low-level Temperature Inversions and Their Effects on Aerosols in the Lower Atmosphere 被引量:2
5
作者 Jun LI Hongbin CHEN +4 位作者 Zhanqing LI Pucai WANG Xuehua FAN Wenying HE Jinqiang ZHANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第11期1235-1250,共16页
High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collec... High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collected at the Atmospheric Radiation Measurement Southern Great Plains climate research facility during 2000–15. The parameters and vertical distribution of temperature inversion layers were found to have strong diurnal and seasonal changes. For surface-based temperature inversion (SBI), the mean frequency and depth of temperature inversion layers were 39.4% and 198 m, respectively. The temperature difference between the top and bottom of SBI was 4.8℃, and so the temperature gradient was 2.4℃(100 m)^-1. The detailed vertical distributions of temperature inversion had been determined, and only the temperature inversion layers below 1000 m showed diurnal and seasonal variations. Mean surface aerosol number concentrations increased by 43.0%, 21.9% and 49.2% when SBIs were present at 0530, 1730 and 2330 LST, respectively. The effect of SBI on surface aerosol concentration was weakest in summer (18.1%) and strongest in winter (58.4%). During elevated temperature inversion events, there was no noticeable difference in surface aerosol number concentrations. Temperature differences and temperature gradients across SBIs correlated fairly well with aerosol number concentrations, especially for temperature gradients. The vertical distribution of aerosol optical properties with and without temperature inversions was different. Surface aerosol measurements were representative of the air within (below), but not above, SBIs and EIs. These results provide a basis for developing a boundary layer aerosol accumulation model and for improving radiative transfer models in the lower atmosphere. 展开更多
关键词 temperature INVERSION AEROSOL LOWER ATMOSPHERE VERTICAL distribution
下载PDF
3-D multi-parameter type traveltime tomography in a spherical coordinate frame: comparison of double and triple class simultaneous inversions
6
作者 Chaoying Bai Jiayu Sun +1 位作者 Xingwang Li Stewart Greenhalgh 《Earthquake Science》 CSCD 2018年第2期62-74,共13页
It is now common practice to perform simultaneous traveltime inversion for the velocity field and the reflector geometry in reflection/refraction tomography, or the velocity field and the hypocenter locations in regio... It is now common practice to perform simultaneous traveltime inversion for the velocity field and the reflector geometry in reflection/refraction tomography, or the velocity field and the hypocenter locations in regional earthquake tomography, but seldom are all three classes of model parameters updated simultaneously. This is mainly due to the trade-off between the different types of model parameters and the lack of different seismic phases to constrain the model parameters. Using a spherical-coordinate ray tracing algorithm for first and later(primary reflected) arrival tracing algorithm in combination with a popular linearized inversion solver, it is possible to simultaneously recover the three classes of model parameters in regional or global tomographic studies. In this paper we incorporate the multistage irregular shortest-path ray tracing algorithm(in a spherical coordinate system) with a subspace inversion solver to formulate a simultaneous inversion algorithm for triple model parameters updating using direct and later arrival time information.Comparison tests for two sets of data(noise free and added noise) indicate that the new triple-class parameter inversion algorithm is capable of obtaining nearly the same results as the double-class parameter inversion scheme. Furthermore,the proposed multi-parameter type inversion method is not sensitive to a modest level of picking error in the traveltime data, and also performs well with a relatively large uncertainty in earthquake hypocentral locations. This shows it to be a feasible and promising approach in regional or global tomographic applications. 展开更多
关键词 simultaneous triple model parameten inversion reflector geometry hypocenter location subspace inversion multistage irregular shortest-path ray tracing
下载PDF
Inversions for MT data in 2D symmetrical anisotropic media
7
作者 杨长福 林长佑 +1 位作者 孙崇赤 李清河 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2005年第3期361-367,共7页
In the paper, a 2D symmetrical anisotropic medium whose strike agrees with one of the horizontal principal axes is considered to develop a corresponding inversion technique. In the specified conditions, if we assume a... In the paper, a 2D symmetrical anisotropic medium whose strike agrees with one of the horizontal principal axes is considered to develop a corresponding inversion technique. In the specified conditions, if we assume an equivalent conductivity anisotropy in both the vertical and dipping directions, i.e., σzz=σyy, the differential equations obtained are formally the same as that for TE and TM modes in the 2D isotropic geoelectrical media. The same inversion technique as that in the 2D isotropic media can be employed to obtain the anisotropic conductivities. It means that the TE and TM inversion results in the isotropic media can be respectively thought as the resistivities in the two principal directions of the symmetrically anisotropic media, which has offered a new approach and a theoretical guidance for interpreting magnetotelluric data. And the inversion technique developed here is used to test the magnetotelluric data in the area of Tianzhu and Yongdeng in Gansu Province, so that the crust anisotropic geoelectrical structures in this region can be obtained. 展开更多
关键词 MAGNETOTELLURICS ANISOTROPY 2D inversion geoelectrical structure
下载PDF
Contributions of shortwave radiation to the formation of temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean:A modeling approach
8
作者 K M Azam Chowdhury Wensheng Jiang +3 位作者 Changwei Bian Guimei Liu Md Kawser Ahmed Shaila Akhter 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第9期19-37,共19页
Variations in incoming shortwave radiation influence the net surface heat flux,contributing to the formation of a temperature inversion.The effects of shortwave radiation on the temperature inversions in the Bay of Be... Variations in incoming shortwave radiation influence the net surface heat flux,contributing to the formation of a temperature inversion.The effects of shortwave radiation on the temperature inversions in the Bay of Bengal and eastern equatorial Indian Ocean have never been investigated.Thus,a high-resolution(horizontal resolution of 0.07°×0.07° with 50 vertical layers) Regional Ocean Modeling System(ROMS) model is utilized to quantify the contributions of shortwave radiation to the temperature inversions in the study domain.Analyses of the mixed layer heat and salt budgets are performed,and different model simulations are compared.The model results suggest that a 30% change in shortwave radiation can change approximately 3% of the temperature inversion area in the Bay of Bengal.Low shortwave radiation reduces the net surface heat flux and cools the mixed layer substantially;it also reduces the evaporation rate,causing less evaporative water vapor losses from the ocean than the typical situation,and ultimately enhances haline stratification.Thus,the rudimentary outcome of this research is that a decrease in shortwave radiation produces more temperature inversion in the study region,which is primarily driven by the net surface cooling and supported by the intensive haline stratification.Moreover,low shortwave radiation eventually intensifies the temperature inversion layer by thickening the barrier layer.This study could be an important reference for predicting how the Indian Ocean climate will respond to future changes in shortwave radiation. 展开更多
关键词 mixed layer cooling haline stratification temperature inversion ROMS model shortwave radiation Bay of Bengal eastern equatorial Indian Ocean
下载PDF
Comparison of deterministic and stochastic approaches to crosshole seismic travel-time inversions
9
作者 YanZhe Zhao YanBin Wang 《Earth and Planetary Physics》 CSCD 2019年第6期547-559,共13页
The Bayesian inversion method is a stochastic approach based on the Bayesian theory.With the development of sampling algorithms and computer technologies,the Bayesian inversion method has been widely used in geophysic... The Bayesian inversion method is a stochastic approach based on the Bayesian theory.With the development of sampling algorithms and computer technologies,the Bayesian inversion method has been widely used in geophysical inversion problems.In this study,we conduct inversion experiments using crosshole seismic travel-time data to examine the characteristics and performance of the stochastic Bayesian inversion based on the Markov chain Monte Carlo sampling scheme and the traditional deterministic inversion with Tikhonov regularization.Velocity structures with two different spatial variations are considered,one with a chessboard pattern and the other with an interface mimicking the Mohorovicicdiscontinuity(Moho).Inversions are carried out with different scenarios of model discretization and source–receiver configurations.Results show that the Bayesian method yields more robust single-model estimations than the deterministic method,with smaller model errors.In addition,the Bayesian method provides the posterior probabilistic distribution function of the model space,which can help us evaluate the quality of the inversion result. 展开更多
关键词 stochastic APPROACH DETERMINISTIC APPROACH Bayesian INVERSION MARKOV Chain Monte Carlo Tikhonov REGULARIZATION
下载PDF
Parameter Inversions of Multi-Layer Media of Mars Polar Region with Validation of SHARAD Data
10
作者 Chuan Liu Ya-Qiu Jin 《International Journal of Astronomy and Astrophysics》 2019年第3期335-353,共19页
HF (high frequency) radar sounder technology has been developed for several missions of Mars surface/subsurface exploration. This paper presents a model of rough surface and stratified sub-surfaces to describe the mul... HF (high frequency) radar sounder technology has been developed for several missions of Mars surface/subsurface exploration. This paper presents a model of rough surface and stratified sub-surfaces to describe the multi-layer structure of Mars polar deposits. Based on numerical simulation of radar echoes from rough surface/stratified interfaces, an inversion approach is developed to obtain the parameters of Polar Layered Deposits, i.e. layers thickness and dielectric constants. As a validation example, the SHARAD radar sounder data of the Promethei Lingula of Mars South Polar region is adopted for parameters inversion. The result of stratification is also analyzed and compared with the optical photo of the deep cliff of Chasma Australe canyon. Dielectric inversions show that the deposit media are not uniform, and the dielectric constants of the Promethei Lingula surfaces are large, and become reduced around the depth of 20 m - 30 m, below where most of the deposits are nearly pure ice, except a few thin layers with a lot of dust. 展开更多
关键词 RADAR Sounder INVERSION of MULTI-LAYER Parameters STRATIFIED Media MARS POLAR Region SHARAD
下载PDF
Strong Earthquake Sequences in Greece during 2008-2014: Moment Tensor Inversions and Fault Plane Discrimination
11
作者 Alexandra Moshou 《Open Journal of Earthquake Research》 2020年第4期323-348,共26页
As is well known, Greece has a significant number of earthquakes each year. Ιn recent years, several earthquakes have occurred in Greece. For this scope, a methodology was used to determine the source parameters. Thi... As is well known, Greece has a significant number of earthquakes each year. Ιn recent years, several earthquakes have occurred in Greece. For this scope, a methodology was used to determine the source parameters. This methodology is based on minimizing the difference between the observed and the synthetic waveforms, using the method Source Parameters Calculation—SPCa <a href="#ref1" target="_blank">[1]</a>. The source parameters, using the proposed methodology, are calculated by comparing observed seismograms and synthetic by inverting data. The synthetics are calculated using the reflectivity method (Kennett, 1983) as implemented by Randall et al. (1994) for a given earth structure. This study includes inversion results for the strongest events that occurred in Greece from 2008 to 2014. For the same events calculated the main fault plane, using the method of Hypocenter Centroid-plot (HC-plot) <a href="#ref2" target="_blank">[2]</a> <a href="#ref3" target="_blank">[3]</a>. This methodology is a simple geometrical method based on the combination between the hypocentral position and the two possible fault planes. 展开更多
关键词 Synthetic Seismograms Moment Tensor Inversion Focal Mechanism Regional Data Nodal Planes
下载PDF
Generalized Inversions of Hadamard and Tensor Products for Matrices
12
作者 Saburou Saitoh 《Advances in Linear Algebra & Matrix Theory》 2014年第2期87-95,共9页
We shall give natural generalized solutions of Hadamard and tensor products equations for matrices by the concept of the Tikhonov regularization combined with the theory of reproducing kernels.
关键词 Reproducing Kernel Positive Definite HERMITIAN MATRIX Tensor PRODUCT HADAMARD PRODUCT GENERALIZED Inverse MATRIX Equation Tikhonov Regularization 100/0 = 0 0/0 = 0 GENERALIZED Fraction GENERALIZED Fractional Function
下载PDF
A Matrix Inequality for the Inversions of the Restrictions of a Positive Definite Hermitian Matrix
13
作者 Weixiong Mai Mo Yan +2 位作者 Tao Qian Matteo Dalla Riva Saburou Saitoh 《Advances in Linear Algebra & Matrix Theory》 2013年第4期55-58,共4页
We exploit the theory of reproducing kernels to deduce a matrix inequality for the inverse of the restriction of a positive definite Hermitian matrix.
关键词 Reproducing Kernel POSITIVE Definite HERMITIAN MATRIX Quadratic Inequality Inversion of POSITIVE Definite HERMITIAN MATRIX Restriction of POSITIVE Definite HERMITIAN MATRIX SCHUR Complement Block MATRIX
下载PDF
The MW5.5 earthquake on August 6,2023,in Pingyuan,Shandong,China:A rupture on a buried fault 被引量:2
14
作者 Zhe Zhang Lisheng Xu Lihua Fang 《Earthquake Science》 2024年第1期1-12,共12页
On August 6,2023,a magnitude MW5.5 earthquake struck Pingyuan County,Dezhou City,Shandong Province,China.This event was significant as no large earthquakes had been recorded in the region for over a century,and no act... On August 6,2023,a magnitude MW5.5 earthquake struck Pingyuan County,Dezhou City,Shandong Province,China.This event was significant as no large earthquakes had been recorded in the region for over a century,and no active fault had been previously identified.This study collects 1309 P-wave arrival times and 866 S-wave arrival times from 74 seismic stations less than 200 km to the epicenter to constrain the spatial distribution of the mainshock and its 125 early aftershocks by the double difference earthquake relocation method,and selects 864 P-waveforms from 288 stations located within 800 km of the epicenter to constrain the focal mechanism solution of the mainshock through centroid moment tensor inversion.The relocation and the inversion indicate,the Pingyuan MW5.5 earthquake was caused by a rupture on a buried fault,likely an extensive segment of the Gaotang fault.This buried fault exhibited a dip of approximately 75°to the northwest,with a strike of 222°,similar to the Gaotang fault.The rupture initiated at the depth of 18.6 km and propagated upward and northeastward.However,the ground surface was not broken.The total duration of the rupture was~6.0 s,releasing the scalar moment of 2.5895×1017 N·m,equivalent to MW5.54.The moment rate reached the maximum only 1.4 seconds after the rupture initiation,and the 90%scalar moment was released in the first 4.6 s.In the first 1.4 seconds of the rupture process,the rupture velocity was estimated to be 2.6 km/s,slower than the local S-wave velocity.As the rupture neared its end,the rupture velocity decreased significantly.This study provides valuable insights into the seismic characteristics of the Pingyuan MW5.5 earthquake,shedding light on the previously unidentified buried fault responsible for the seismic activity in the region.Understanding the behavior of such faults is crucial for assessing seismic hazards and enhancing earthquake preparedness in the future. 展开更多
关键词 Shandong Pingyuan MW5.5 earthquake double-difference earthquake location centroid moment tensor inversion buried fault
下载PDF
Linearized waveform inversion for vertical transversely isotropic elastic media:Methodology and multi-parameter crosstalk analysis
15
作者 Ke Chen Lu Liu +5 位作者 Li-Nan Xu Fei Hu Yuan Yang Jia-Hui Zuo Le-Le Zhang Yang Zhao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期252-271,共20页
Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuit... Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuities.More specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection data.On the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface formulations.Such seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted parameters.Although there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic inversion.Usually,seismic migration and inversion techniques assume an acoustic or isotropic elastic medium.Unconventional reservoirs such as shale and tight sand formation have notable anisotropic property.We present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)symmetry.It is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference model.Our proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each iteration.We derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state method.The inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based images.We have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy parameters.Especially,the Thomsen parameter is the most difficult to resolve.We also analyze the multi-parameter crosstalk using scattering radiation patterns.The linearized waveform inversion for VTI-elastic media presented in this article provides quantitative information of the rock properties that has the potential to help identify hydrocarbon reservoirs. 展开更多
关键词 Elastic ANISOTROPY Least-squares imaging Waveform inversion Computational geophysics
下载PDF
Layer-Valley Hall Effect under Inversion and Time-Reversal Symmetries
16
作者 赵交交 刘贵斌 +3 位作者 陈鹏 姚裕贵 张广宇 杜罗军 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第6期88-97,共10页
Hall effects have been the central paradigms in modern physics,materials science and practical applications,and have led to many exciting breakthroughs,including the discovery of topological Chern invariants and the r... Hall effects have been the central paradigms in modern physics,materials science and practical applications,and have led to many exciting breakthroughs,including the discovery of topological Chern invariants and the revolution of metrological resistance standard.To date,the Hall effects have mainly focused on a single degree of freedom(Do F),and most of them require the breaking of spatial-inversion and/or time-reversal symmetries.Here we demonstrate a new type of Hall effect,i.e.,layer-valley Hall effect,based on a combined layer-valley Do F characterized by the product of layer and valley indices.The layer-valley Hall effect has a quantum origin arising from the layer-valley contrasting Berry curvature,and can occur in nonmagnetic centrosymmetric crystals with both spatial-inversion and time-reversal symmetries,transcending the symmetry constraints of single Do F Hall effect based on the constituent layer or valley index.Moreover,the layer-valley Hall effect is highly tunable and shows a W-shaped pattern in response to the out-of-plane electric fields.Additionally,we discuss the potential detection approaches and material-specific design principles of layer-valley Hall effect.Our results demonstrate novel Hall physics and open up exotic paradigms for new research direction of layer-valleytronics that exploits the quantum nature of the coupled layer-valley DoF. 展开更多
关键词 quantum INVERSION CURVATURE
下载PDF
Uncertainty quantification of inverse analysis for geomaterials using probabilistic programming
17
作者 Hongbo Zhao Shaojun Li +3 位作者 Xiaoyu Zang Xinyi Liu Lin Zhang Jiaolong Ren 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期895-908,共14页
Uncertainty is an essentially challenging for safe construction and long-term stability of geotechnical engineering.The inverse analysis is commonly utilized to determine the physico-mechanical parameters.However,conv... Uncertainty is an essentially challenging for safe construction and long-term stability of geotechnical engineering.The inverse analysis is commonly utilized to determine the physico-mechanical parameters.However,conventional inverse analysis cannot deal with uncertainty in geotechnical and geological systems.In this study,a framework was developed to evaluate and quantify uncertainty in inverse analysis based on the reduced-order model(ROM)and probabilistic programming.The ROM was utilized to capture the mechanical and deformation properties of surrounding rock mass in geomechanical problems.Probabilistic programming was employed to evaluate uncertainty during construction in geotechnical engineering.A circular tunnel was then used to illustrate the proposed framework using analytical and numerical solution.The results show that the geomechanical parameters and associated uncertainty can be properly obtained and the proposed framework can capture the mechanical behaviors under uncertainty.Then,a slope case was employed to demonstrate the performance of the developed framework.The results prove that the proposed framework provides a scientific,feasible,and effective tool to characterize the properties and physical mechanism of geomaterials under uncertainty in geotechnical engineering problems. 展开更多
关键词 Geological engineering Geotechnical engineering Inverse analysis Uncertainty quantification Probabilistic programming
下载PDF
A Composite Ansatz for Calculation of Dynamical Structure Factor
18
作者 张玉佩 莫崇杰 +1 位作者 张平 康炜 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第1期92-103,共12页
We propose an ansatz without adjustable parameters for the calculation of a dynamical structure factor.The ansatz combines the quasi-particle Green’s function,especially the contribution from the renormalization fact... We propose an ansatz without adjustable parameters for the calculation of a dynamical structure factor.The ansatz combines the quasi-particle Green’s function,especially the contribution from the renormalization factor,and the exchange-correlation kernel from time-dependent density functional theory together,verified for typical metals and semiconductors from a plasmon excitation regime to the Compton scattering regime.It has the capability to reconcile both small-angle and large-angle inelastic x-ray scattering(IXS)signals with muchimproved accuracy,which can be used as the theoretical base model,in inversely inferring electronic structures of condensed matter from IXS experimental signals directly.It may also be used to diagnose thermal parameters,such as temperature and density,of dense plasmas in x-ray Thomson scattering experiments. 展开更多
关键词 EXCITATION INVERSE verified
下载PDF
Sliding and damming properties of granular debris with different geometric configurations and grain size distributions
19
作者 HE Ligeng TAN Longmeng +2 位作者 YANG Xingguo ZHOU Jiawen LIAO Haimei 《Journal of Mountain Science》 SCIE CSCD 2024年第3期932-951,共20页
Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of g... Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sorting due to collisions among the grains and between the grain and the base. The impact of grain on the horizontal channel further aids grain sorting and contributes to inverse grading. The proposed classification of three geometric configurations in our study enhances the understanding of damming properties from the view of mechanism, which provides valuable insights for related study about damming granular debris. 展开更多
关键词 Landslide dam Geometric configuration Energy dissipation Inverse grading Physical experiment
下载PDF
A VGGNet-based correction for satellite altimetry-derived gravity anomalies to improve the accuracy of bathymetry to depths of 6500 m
20
作者 Xiaolun Chen Xiaowen Luo +6 位作者 Ziyin Wu Xiaoming Qin Jihong Shang Huajun Xu Bin Li Mingwei Wang Hongyang Wan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第1期112-122,共11页
Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the... Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the seafloor has been precisely modeled to date,and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data.In this study,we introduce a pretrained visual geometry group network(VGGNet)method based on deep learning.To apply this method,we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter,which has a larger spatial coverage,based on the former,which is considered the true value and is more accurate.After obtaining the corrected high-precision gravity model,it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation.We choose four data pairs collected from different environments,i.e.,the Southern Ocean,Pacific Ocean,Atlantic Ocean and Caribbean Sea,to evaluate the topographic correction results of the model.The experiments show that the coefficient of determination(R~2)reaches 0.834 among the results of the four experimental groups,signifying a high correlation.The standard deviation and normalized root mean square error are also evaluated,and the accuracy of their performance improved by up to 24.2%compared with similar research done in recent years.The evaluation of the R^(2) values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research.Finally,the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21%within 1%of the total water depths,which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results. 展开更多
关键词 gravity anomaly bathymetry inversion VGGNet multibeam sonar satellite altimetry
下载PDF
上一页 1 2 143 下一页 到第
使用帮助 返回顶部