期刊文献+
共找到112,320篇文章
< 1 2 250 >
每页显示 20 50 100
Contrasts of bimodal tropical instability waves(TIWs)-induced wind stress perturbations in the Pacific Ocean among observations,ocean models,and coupled climate models
1
作者 Kai MA Chuanyu LIU +1 位作者 Junli XU Fan WANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第1期1-23,共23页
The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the ... The coupling between wind stress perturbations and sea surface temperature(SST)perturbations induced by tropical instability waves(TIWs)in the Pacific Ocean has been revealed previously and proven crucial to both the atmosphere and ocean.However,an overlooked fact by previous studies is that the loosely defined“TIWs”actually consist of two modes,including the Yanai wave-based TIW on the equator(hereafter eTIW)and the Rossby wave-based TIW off the equator(hereafter vTIW).Hence,the individual feedbacks of the wind stress to the bimodal TIWs remain unexplored.In this study,individual coupling relationships are established for both eTIW and v TIW,including the relationship between the TIW-induced SST perturbations and two components of wind stress perturbations,and the relationship between the TIW-induced wind stress perturbation divergence(curl)and the downwind(crosswind)TIW-induced SST gradients.Results show that,due to different distributions of eTIW and vTIW,the coupling strength induced by the eTIW is stronger on the equator,and that by the vTIW is stronger off the equator.The results of any of eTIW and vTIW are higher than those of the loosely defined TIWs.We further investigated how well the coupling relationships remained in several widely recognized oceanic general circulation models and fully coupled climate models.However,the coupling relationships cannot be well represented in most numerical models.Finally,we confirmed that higher resolution usually corresponds to more accurate simulation.Therefore,the coupling models established in this study are complementary to previous research and can be used to refine the oceanic and coupled climate models. 展开更多
关键词 bimodal tropical instability waves mesoscale air-sea interaction coupled models Yanai wave
下载PDF
Impact of Perturbation Schemes on the Ensemble Prediction in a Coupled Lorenz Model 被引量:1
2
作者 Qian ZOU Quanjia ZHONG +4 位作者 Jiangyu MAO Ruiqiang DING Deyu LU Jianping LI Xuan LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第3期501-513,共13页
Based on a simple coupled Lorenz model,we investigate how to assess a suitable initial perturbation scheme for ensemble forecasting in a multiscale system involving slow dynamics and fast dynamics.Four initial perturb... Based on a simple coupled Lorenz model,we investigate how to assess a suitable initial perturbation scheme for ensemble forecasting in a multiscale system involving slow dynamics and fast dynamics.Four initial perturbation approaches are used in the ensemble forecasting experiments:the random perturbation(RP),the bred vector(BV),the ensemble transform Kalman filter(ETKF),and the nonlinear local Lyapunov vector(NLLV)methods.Results show that,regardless of the method used,the ensemble averages behave indistinguishably from the control forecasts during the first few time steps.Due to different error growth in different time-scale systems,the ensemble averages perform better than the control forecast after very short lead times in a fast subsystem but after a relatively long period of time in a slow subsystem.Due to the coupled dynamic processes,the addition of perturbations to fast variables or to slow variables can contribute to an improvement in the forecasting skill for fast variables and slow variables.Regarding the initial perturbation approaches,the NLLVs show higher forecasting skill than the BVs or RPs overall.The NLLVs and ETKFs had nearly equivalent prediction skill,but NLLVs performed best by a narrow margin.In particular,when adding perturbations to slow variables,the independent perturbations(NLLVs and ETKFs)perform much better in ensemble prediction.These results are simply implied in a real coupled air–sea model.For the prediction of oceanic variables,using independent perturbations(NLLVs)and adding perturbations to oceanic variables are expected to result in better performance in the ensemble prediction. 展开更多
关键词 ensemble prediction nonlinear local Lyapunov vector(NLLV) ensemble transform Kalman filter(ETKF) coupled air-sea models
下载PDF
A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics 被引量:2
3
作者 Qian Zhang Wen-Dong Wang +4 位作者 Yu-Liang Su Wei Chen Zheng-Dong Lei Lei Li Yong-Mao Hao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期327-342,共16页
A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes... A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation. 展开更多
关键词 Multi-scale coupled flow Stress sensitivity Shale oil Micro-scale effect Fractal theory
下载PDF
Coupled multiphysical model for investigation of influence factors in the application of microbially induced calcite precipitation 被引量:1
4
作者 Xuerui Wang Pavan Kumar Bhukya +1 位作者 Dali Naidu Arnepalli Shuang Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2232-2249,共18页
The study presents a comprehensive coupled thermo-bio-chemo-hydraulic(T-BCH)modeling framework for stabilizing soils using microbially induced calcite precipitation(MICP).The numerical model considers relevant multiph... The study presents a comprehensive coupled thermo-bio-chemo-hydraulic(T-BCH)modeling framework for stabilizing soils using microbially induced calcite precipitation(MICP).The numerical model considers relevant multiphysics involved in MICP,such as bacterial ureolytic activities,biochemical reactions,multiphase and multicomponent transport,and alteration of the porosity and permeability.The model incorporates multiphysical coupling effects through well-established constitutive relations that connect parameters and variables from different physical fields.It was implemented in the open-source finite element code OpenGeoSys(OGS),and a semi-staggered solution strategy was designed to solve the couplings,allowing for flexible model settings.Therefore,the developed model can be easily adapted to simulate MICP applications in different scenarios.The numerical model was employed to analyze the effect of various factors,including temperature,injection strategies,and application scales.Besides,a TBCH modeling study was conducted on the laboratory-scale domain to analyze the effects of temperature on urease activity and precipitated calcium carbonate.To understand the scale dependency of MICP treatment,a large-scale heterogeneous domain was subjected to variable biochemical injection strategies.The simulations conducted at the field-scale guided the selection of an injection strategy to achieve the desired type and amount of precipitation.Additionally,the study emphasized the potential of numerical models as reliable tools for optimizing future developments in field-scale MICP treatment.The present study demonstrates the potential of this numerical framework for designing and optimizing the MICP applications in laboratory-,prototype-,and field-scale scenarios. 展开更多
关键词 MULTIPHYSICS Microbially induced calcite precipitation(MICP) coupled thermo-bio-chemo-hydraulic(TBCH) model OpenGeoSys(OGS) Influence factors
下载PDF
Alternative Methods of Regular and Singular Perturbation Problems
5
作者 Boampong Asare Manohar Sah Ram Krishna Hona 《Applied Mathematics》 2024年第10期687-708,共22页
Making exact approximations to solve equations distinguishes applied mathematicians from pure mathematicians, physicists, and engineers. Perturbation problems, both regular and singular, are pervasive in diverse field... Making exact approximations to solve equations distinguishes applied mathematicians from pure mathematicians, physicists, and engineers. Perturbation problems, both regular and singular, are pervasive in diverse fields of applied mathematics and engineering. This research paper provides a comprehensive overview of algebraic methods for solving perturbation problems, featuring a comparative analysis of their strengths and limitations. Serving as a valuable resource for researchers and practitioners, it offers insights and guidance for tackling perturbation problems in various disciplines, facilitating the advancement of applied mathematics and engineering. 展开更多
关键词 perturbation Regular perturbation Singular perturbation Asymptotic Expansion Matched Asymptotic Strained Coordinates Multiple Scales
下载PDF
Growth of ablative Rayleigh-Taylor instability induced by time-varying heat-flux perturbation
6
作者 Yang Liu De-Hua Zhang +6 位作者 Jing-Fei Xin Yudong Pu Jun Li Tao Tao Dejun Sun Rui Yan Jian Zheng 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第1期85-93,共9页
The evolution of ablative Rayleigh–Taylor instability(ARTI)induced by single-mode stationary and time-varying perturbations in heat flux is studied numerically in two dimensions.Compared with the stationary case,time... The evolution of ablative Rayleigh–Taylor instability(ARTI)induced by single-mode stationary and time-varying perturbations in heat flux is studied numerically in two dimensions.Compared with the stationary case,time-varying heat-flux perturbation mitigates ARTI growth because of the enhanced thermal smoothing induced by the wave-like traveling heat flux.A resonance is found to form when the phase velocity of the heat-flux perturbation matches the average sound speed in the ablation region.In the resonant regime,the coherent density and temperature fluctuations enhance the electron thermal conduction in the ablation region and lead to larger ablation pressure and effective acceleration,which consequently yield higher linear growth rate and saturated bubble velocity.The enhanced effective acceleration offers increased implosion velocity but can also compromise the integrity of inertial confinement fusion shells by causing faster ARTI growth. 展开更多
关键词 perturbation STATIONARY ACCELERATION
下载PDF
A proteomic landscape of pharmacologic perturbations for functional relevance
7
作者 Zhiwei Liu Shangwen Jiang +8 位作者 Bingbing Hao Shuyu Xie Yingluo Liu Yuqi Huang Heng Xu Cheng Luo Min Huang Minjia Tan Jun-Yu Xu 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第1期128-139,共12页
Pharmacological perturbation studies based on protein-level signatures are fundamental for drug discovery. In the present study, we used a mass spectrometry (MS)-based proteomic platform to profile the whole proteome ... Pharmacological perturbation studies based on protein-level signatures are fundamental for drug discovery. In the present study, we used a mass spectrometry (MS)-based proteomic platform to profile the whole proteome of the breast cancer MCF7 cell line under stress induced by 78 bioactive compounds. The integrated analysis of perturbed signal abundance revealed the connectivity between phenotypic behaviors and molecular features in cancer cells. Our data showed functional relevance in exploring the novel pharmacological activity of phenolic xanthohumol, as well as the noncanonical targets of clinically approved tamoxifen, lovastatin, and their derivatives. Furthermore, the rational design of synergistic inhibition using a combination of histone methyltransferase and topoisomerase was identified based on their complementary drug fingerprints. This study provides rich resources for the proteomic landscape of drug responses for precision therapeutic medicine. 展开更多
关键词 PROTEOMICS Drug perturbation Drug target Drug combination
下载PDF
Image Enhancement via Associated Perturbation Removal and Texture Reconstruction Learning
8
作者 Kui Jiang Ruoxi Wang +3 位作者 Yi Xiao Junjun Jiang Xin Xu Tao Lu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第11期2253-2269,共17页
Degradation under challenging conditions such as rain, haze, and low light not only diminishes content visibility, but also results in additional degradation side effects, including detail occlusion and color distorti... Degradation under challenging conditions such as rain, haze, and low light not only diminishes content visibility, but also results in additional degradation side effects, including detail occlusion and color distortion. However, current technologies have barely explored the correlation between perturbation removal and background restoration, consequently struggling to generate high-naturalness content in challenging scenarios. In this paper, we rethink the image enhancement task from the perspective of joint optimization: Perturbation removal and texture reconstruction. To this end, we advise an efficient yet effective image enhancement model, termed the perturbation-guided texture reconstruction network(PerTeRNet). It contains two subnetworks designed for the perturbation elimination and texture reconstruction tasks, respectively. To facilitate texture recovery,we develop a novel perturbation-guided texture enhancement module(PerTEM) to connect these two tasks, where informative background features are extracted from the input with the guidance of predicted perturbation priors. To alleviate the learning burden and computational cost, we suggest performing perturbation removal in a sub-space and exploiting super-resolution to infer high-frequency background details. Our PerTeRNet has demonstrated significant superiority over typical methods in both quantitative and qualitative measures, as evidenced by extensive experimental results on popular image enhancement and joint detection tasks. The source code is available at https://github.com/kuijiang94/PerTeRNet. 展开更多
关键词 Association learning attention mechanism image enhancement perturbation modeling
下载PDF
Nonlinearly induced entanglement in dissipatively coupled optomechanical system
9
作者 杨文全 冷轩 +1 位作者 程泂 张闻钊 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期255-260,共6页
Nonlinearly induced steady-state photon–phonon entanglement of a dissipative coupled system is studied in the bistable regime. Quantum dynamical characteristics are analysed by solving the mean-field and fluctuation ... Nonlinearly induced steady-state photon–phonon entanglement of a dissipative coupled system is studied in the bistable regime. Quantum dynamical characteristics are analysed by solving the mean-field and fluctuation equations of the system. It is shown that dissipative coupling can induce bistable behaviour for the effective dissipation of the system.Under suitable parameters, one of the steady states significantly reduces the dissipative effect of the system. Consequently,a larger steady-state entanglement can be achieved compared to linear dynamics. Furthermore, the experimental feasibility of the parameters is analysed. Our results provide a new perspective for the implementation of steady-state optomechanical entanglement. 展开更多
关键词 ENTANGLEMENT optomechanical system dissipatively coupling
下载PDF
A generalization of Banach's lemma and its applications to perturbations of bounded linear operators
10
作者 WANG Zi DING Jiu WANG Yu-wen 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第2期363-369,共7页
Let X be a Banach space and let P:X→X be a bounded linear operator.Using an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear ... Let X be a Banach space and let P:X→X be a bounded linear operator.Using an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear operator on X,and a bound on its spectral radius is also obtained.This generalizes the classic Banach lemma.We apply the result to the perturbation analysis of general bounded linear operators on X with commutative perturbations. 展开更多
关键词 Banach lemma spectral radius generalized inverse perturbation analysis
下载PDF
Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams
11
作者 Zahra Ramezandoust Abbas Tajaddini Panam Zarfam 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期691-712,共22页
Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe earthquakes.This study aimed to analytically... Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe earthquakes.This study aimed to analytically evaluate the seismic behavior of flexural and shear fuse beams situated in short-,medium-and high-rise RC buildings that have HCSWs.Three building groups hypothetically located in a high seismic hazard zone were studied.A series of 2D nonlinear time history analyses was accomplished in OpenSees,using the ground motion records scaled at the design basis earthquake level.It was found that the effectiveness of fuses in HCSWs depends on various factors such as size and scale of the building,allowable rotation value,inter-story drift ratio,residual drift quantity,energy dissipation value of the fuses,etc.The results show that shear fuses better meet the requirements of rotations and drifts.In contrast,flexural fuses dissipate more energy,but their sectional stiffness should increase to meet other requirements.It was concluded that adoption of proper fuses depends on the overall scale of the building and on how associated factors are considered. 展开更多
关键词 hybrid coupled shear wall steel fuse coupling beam shear and flexural fuse nonlinear dynamic analysis seismic performance
下载PDF
An Initial Perturbation Method for the Multiscale Singular Vector in Global Ensemble Prediction
12
作者 Xin LIU Jing CHEN +6 位作者 Yongzhu LIU Zhenhua HUO Zhizhen XU Fajing CHEN Jing WANG Yanan MA Yumeng HAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第3期545-563,共19页
Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather Prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial pertur... Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather Prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial perturbation method tends only to capture synoptic scale initial uncertainty rather than mesoscale uncertainty in global ensemble prediction. To address this issue, a multiscale SV initial perturbation method based on the China Meteorological Administration Global Ensemble Prediction System(CMA-GEPS) is proposed to quantify multiscale initial uncertainty. The multiscale SV initial perturbation approach entails calculating multiscale SVs at different resolutions with multiple linearized physical processes to capture fast-growing perturbations from mesoscale to synoptic scale in target areas and combining these SVs by using a Gaussian sampling method with amplitude coefficients to generate initial perturbations. Following that, the energy norm,energy spectrum, and structure of multiscale SVs and their impact on GEPS are analyzed based on a batch experiment in different seasons. The results show that the multiscale SV initial perturbations can possess more energy and capture more mesoscale uncertainties than the traditional single-SV method. Meanwhile, multiscale SV initial perturbations can reflect the strongest dynamical instability in target areas. Their performances in global ensemble prediction when compared to single-scale SVs are shown to(i) improve the relationship between the ensemble spread and the root-mean-square error and(ii) provide a better probability forecast skill for atmospheric circulation during the late forecast period and for short-to medium-range precipitation. This study provides scientific evidence and application foundations for the design and development of a multiscale SV initial perturbation method for the GEPS. 展开更多
关键词 multiscale uncertainty singular vector initial perturbation global ensemble prediction system
下载PDF
Volcanically Driven Terrestrial Environmental Perturbations during the Carnian Pluvial Episode in the Eastern Tethys
13
作者 Naveed Ur RAHMAN XIAN Benzhong +4 位作者 FANG Linhao CHEN Sirui CHEN Peng Zaheen ULLAH WANG Pengyu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第3期753-770,共18页
The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlat... The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood.Records of negative carbon isotopic excursions(NCIEs),mercury(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions.The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe,the UK,and South and North China.The U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun section.HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions.The records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP during the CPE.Anoxia,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin. 展开更多
关键词 Chang 7 Member oil shale Carnian Pluvial Episode VOLCANISM environmental perturbations
下载PDF
Comparison of transport coefficients before and after density pump-out induced by resonant magnetic perturbation using a BOUT++ six-field model on the EAST tokamak
14
作者 邓成成 刘子奚 +22 位作者 夏天阳 刘彦君 厉鹏程 龙飞飞 高翔 王守信 李国强 刘海庆 臧庆 李玖瑛 杨康宁 吴茗甫 尹晓宇 李弘 谢锦林 兰涛 毛文哲 刘阿娣 周楚 丁卫星 庄革 刘万东 the EAST Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第6期111-119,共9页
Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modula... Many experiments have demonstrated that resonant magnetic perturbation(RMP) can affect the turbulent transport at the edge of the tokamak. Through the Experimental Advanced Superconducting Tokamak(EAST) density modulation experiment, the particle transport coefficients were calculated using the experimental data, and the result shows that the particle transport coefficients increase with RMP. In this study, the six-field two-fluid model in BOUT++ is used to simulate the transport before and after density pump-out induced by RMP,respectively referred as the case without RMP and the case with RMP. In the linear simulations,the instabilities generally decreases for cases with RMP. In the nonlinear simulation, ELM only appears in the case without RMP. Additionally, the particle transport coefficient was analyzed,and the result shows that the particle transport coefficient becomes larger for the case with RMP,which is consistent with the experimental conclusion. Moreover, its magnitude is comparable to the results calculated from experimental data. 展开更多
关键词 BOUT++ resonant magnetic perturbation(RMP) transport coefficients
下载PDF
Application of three-dimensional MHD equilibrium calculation coupled with plasma response to island divertor experiments on J-TEXT
15
作者 Wei XIE Yunfeng LIANG +13 位作者 Zhonghe JIANG Yasuhiro SUZUKI Li LI Jiankun HUA Jie HUANG Alexander KNIEPS Song ZHOU Feiyue MAO Xin XU Keze LI Yutong YANG Ziyang JIN Cunkai LI the J-TEXT Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第11期71-86,共16页
Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MA... Three-dimensional(3D) equilibrium calculations, including the plasma rotation shielding effect to resonant magnetic perturbations(RMPs) produced by the island divertor(ID) coils, were carried out using the HINT and MARS-F codes on J-TEXT. Validation of 3D equilibrium calculations with experimental observations demonstrates that the shielding effect will prevent the penetration of the edge m/n = 3/1 mode component when the ID coil current is 4 k A, while change the size of magnetic islands once the current exceeds the penetration threshold. This indicates that equilibrium calculations including the plasma rotation shielding effect to RMPs can lead to better agreements with experimental observations compared to the vacuum approximation method. Additionally, the magnetic topology at the boundary undergoes changes,impacting the interaction between the plasma and the target plate. These results may be important in understanding RMP effects on edge transport and magnetohydrodynamic(MHD)instability control, as well as divertor heat and particle flux distribution control. 展开更多
关键词 magnetic topology resonant magnetic perturbation 3D equilibrium shielding effect
下载PDF
Research on perturbation of neutron fluence rate in a closed thermal neutron field due to medium materials
16
作者 Jun-Kai Yang Ping-Quan Wang +8 位作者 Zhi-Meng Hu Fan Li Jun-Mei Zeng Lin Xiao Hong-Yu Guo Jian Zhang Giuseppe Gorini Hui Zhang Chungming Paul Chu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第10期222-232,共11页
The neutron radiation field has vital applications in areas such as biomedicine,geology,radiation safety,and many others for neutron detection and neutron metrology.Correcting neutron fluence rate perturbation accurat... The neutron radiation field has vital applications in areas such as biomedicine,geology,radiation safety,and many others for neutron detection and neutron metrology.Correcting neutron fluence rate perturbation accurately is an important yet challenging problem.This study proposes a correction method that analyzes three physical processes.This method,which transforms the detection process from point detection to area detection,is based on a novel physical model and has been validated through theoretical analyses,experiments,and simulations.According to the average differences between the calculated and experimental results,the new method(1.67%)demonstrated better accuracy than the traditional simulation(2.17%).In a closed thermal neutron radiation field,the detector or strong neutron absorption material significantly perturbs the neutron fluence rate,whereas its impact on the energy spectrum shape and neutron directionality is relatively minor.Furthermore,based on the calculation results of the perturbation rate formula for medium materials with different compositions and sizes,the larger the volume and capture cross section of the medium,the higher the perturbation rate generated in the closed radiation field. 展开更多
关键词 perturbation rate Area detection Three-dimensional neutron energy spectrum Closed radiation field
下载PDF
Effects of asymmetric coupling and boundary on the dynamic behaviors of a random nearest neighbor coupled system
17
作者 徐玲 姜磊 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期309-322,共14页
This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First, the study derivative analytical stability and synchronization conditions for the asymmetrically... This study investigates the dynamical behaviors of nearest neighbor asymmetric coupled systems in a confined space.First, the study derivative analytical stability and synchronization conditions for the asymmetrically coupled system in an unconfined space, which are then validated through numerical simulations. Simulation results show that asymmetric coupling has a significant impact on synchronization conditions. Moreover, it is observed that irrespective of whether the system is confined, an increase in coupling asymmetry leads to a hastened synchronization pace. Additionally, the study examines the effects of boundaries on the system's collective behaviors via numerical experiments. The presence of boundaries ensures the system's stability and synchronization, and reducing these boundaries can expedite the synchronization process and amplify its effects. Finally, the study reveals that the system's output amplitude exhibits stochastic resonance as the confined boundary size increases. 展开更多
关键词 asymmetric coupled confined space SYNCHRONIZATION stochastic resonance stability
下载PDF
Generalized nth-Order Perturbation Method Based on Loop Subdivision Surface Boundary Element Method for Three-Dimensional Broadband Structural Acoustic Uncertainty Analysis
18
作者 Ruijin Huo Qingxiang Pei +1 位作者 Xiaohui Yuan Yanming Xu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期2053-2077,共25页
In this paper,a generalized nth-order perturbation method based on the isogeometric boundary element method is proposed for the uncertainty analysis of broadband structural acoustic scattering problems.The Burton-Mill... In this paper,a generalized nth-order perturbation method based on the isogeometric boundary element method is proposed for the uncertainty analysis of broadband structural acoustic scattering problems.The Burton-Miller method is employed to solve the problem of non-unique solutions that may be encountered in the external acoustic field,and the nth-order discretization formulation of the boundary integral equation is derived.In addition,the computation of loop subdivision surfaces and the subdivision rules are introduced.In order to confirm the effectiveness of the algorithm,the computed results are contrasted and analyzed with the results under Monte Carlo simulations(MCs)through several numerical examples. 展开更多
关键词 perturbation method loop subdivision surface isogeometric boundary element method uncertainty analysis
下载PDF
Customized modulation on plasma uniformity by non-uniform magnetic field in capacitively coupled plasma
19
作者 王森 张权治 +2 位作者 马方方 Maksudbek YUSUPOV 王友年 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第6期79-87,共9页
A two-dimensional fluid model based on COMSOL Multiphysics is developed to investigate the modulation of static magnetic field on plasma homogeneity in a capacitively coupled plasma(CCP)chamber. To generate a static m... A two-dimensional fluid model based on COMSOL Multiphysics is developed to investigate the modulation of static magnetic field on plasma homogeneity in a capacitively coupled plasma(CCP)chamber. To generate a static magnetic field, direct current is applied to a circular coil located at the top of the chamber. By adjusting the magnetic field's configuration, which is done by altering the coil current and position, both the plasma uniformity and density can be significantly modulated. In the absence of the magnetic field, the plasma density exhibits an inhomogeneous distribution characterized by higher values at the plasma edge and lower values at the center. The introduction of a magnetic field generated by coils results in a significant increase in electron density near the coils. Furthermore, an increase in the sets of coils improves the uniformity of the plasma. By flexibly adjusting the positions of the coils and the applied current,a substantial enhancement in overall uniformity can be achieved. These findings demonstrate the feasibility of using this method for achieving uniform plasma densities in industrial applications. 展开更多
关键词 COMSOL capacitively coupled plasma plasma uniformity magnetic field
下载PDF
A Coupled Thermomechanical Crack Propagation Behavior of Brittle Materials by Peridynamic Differential Operator
20
作者 Tianyi Li Xin Gu Qing Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期339-361,共23页
This study proposes a comprehensive,coupled thermomechanical model that replaces local spatial derivatives in classical differential thermomechanical equations with nonlocal integral forms derived from the peridynamic... This study proposes a comprehensive,coupled thermomechanical model that replaces local spatial derivatives in classical differential thermomechanical equations with nonlocal integral forms derived from the peridynamic differential operator(PDDO),eliminating the need for calibration procedures.The model employs a multi-rate explicit time integration scheme to handle varying time scales in multi-physics systems.Through simulations conducted on granite and ceramic materials,this model demonstrates its effectiveness.It successfully simulates thermal damage behavior in granite arising from incompatible mineral expansion and accurately calculates thermal crack propagation in ceramic slabs during quenching.To account for material heterogeneity,the model utilizes the Shuffle algorithm andWeibull distribution,yielding results that align with numerical simulations and experimental observations.This coupled thermomechanical model shows great promise for analyzing intricate thermomechanical phenomena in brittle materials. 展开更多
关键词 Peridynamic differential operator thermomechanical coupling HETEROGENEITY numerical simulation
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部