检索结果-南通市图书馆

Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： s R Wu B q Wang Z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de sitter BH surrounded by quintessence(RN-dsq).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dsq under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dsq are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： q.K.Liu L.Deng q.Wang X.Zhang F.q.Meng Y.P.Wang Y.q.Gao H.B.Cai s.P.Zhu Graduate school China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China school of Nuclear science and Technology University of Science and Technology of ChinaHefei 230026China shanghai Institute of Laser Plasma Shanghai 201800China HEDPs Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China school of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BsRs)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BsRs evolution driven by broadband lasers.

关键词： scattering kinetic simplified

Rescattering of stimulated Raman side scattering in nonuniform plasmas

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第5期9卷 68-76页

作者： s.Tan q.Wang Y.Chen W.B.Yao C.Z.Xiao J.F.Myatt school of Physics and Electronics Hunan UniversityChangsha 410082China Institute of Applied Physics and Computational Mathematics Beijing 100094China school of Electrical and Information Engineering Anhui University of Science and TechnologyHuainanAnhui 232001China Department of Electrical and Computer Engineering University of Alberta9211116 St.NWEdmontonAlberta T6G 1H9Canada

Rescattering of stimulated Raman side scattering(sRss)is observed for the first time via two-dimensional(2D)particle-in-cell(PIC)*** construct a theoretical model for the rescattering process,which can predict the region of occurrence of mth-order sRss and estimate its *** rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion *** electrons produced by second-order sRss propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order sRss,but there is no cascade acceleration to produce superhot *** studies for a wide range of ignition conditions show that sRss and associated rescatterings are robust and important processes in inertial confinement fusion.

关键词： nonuniform acceleration scattering

Experimental study of corner separation and unsteady characteristics in linear compressor cascades with and without sweeping jet actuator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2024年第3期13卷 360-374页

作者： s.W.Chen W.H.Li C.Xu q.H.Meng school of Energy science and Engineering Harbin Institute of TechnologyHarbinHeilongjiang 150001China AVIC shenyang Aircraft Design and Research Institute Shenyang 110035China

sweeping jet actuator(sJA)has been widely applied for activeflow control in *** this paper,the sJA character in compressor cascade and its performance for separation control in innerflows are ***-averaged and transientflowfield measurement,together with visualization methods are *** is found that endwall effects are important for both sJA behaviors and sJA performance for separation control in compressor *** is a maximum of 12.7%total pressure loss reduction with sJA placed near the separation position,close to the endwall and under *** characteristic frequencies in theflowfield contribute to the capture of influence regions of vortices and excitation *** concentrated shedding vortices and sJA jets impact region helped to judge that sJA energizes low momentumfluids in a large region and matches the high loss core *** be concrete,theflow separation control mechanism of sJA lies on the interruption of the blade suction surface boundary layer development and the restriction of the lifting of the boundary layer from end-wall towards blade suction surface.

关键词： Compressor cascade Activeflow control sweeping jet actuator Corner separation Oilflow visualization

An Enhanced Ensemble-Based Long short-Term Memory Approach for Traffic Volume Prediction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 3585-3602页

作者： Duy quang Tran Huy q.Tran Minh Van Nguyen Faculty of Civil Engineering Nha Trang UniversityNha Trang650000Vietnam Robotics and Mechatronics Research Group Faculty of Engineering and TechnologyNguyen Tat Thanh UniversityHo Chi Minh City700000Vietnam Department of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City700000Vietnam

With the advancement of artificial intelligence,traffic forecasting is gaining more and more interest in optimizing route planning and enhancing service *** volume is an influential parameter for planning and operating traffic *** study proposed an improved ensemble-based deep learning method to solve traffic volume prediction problems.A set of optimal hyperparameters is also applied for the suggested approach to improve the performance of the learning *** fusion of these methodologies aims to harness ensemble empirical mode decomposition’s capacity to discern complex traffic patterns and long short-term memory’s proficiency in learning temporal ***,a dataset for automatic vehicle identification is obtained and utilized in the preprocessing stage of the ensemble empirical mode decomposition *** second aspect involves predicting traffic volume using the long short-term memory ***,the study employs a trial-and-error approach to select a set of optimal hyperparameters,including the lookback window,the number of neurons in the hidden layers,and the gradient descent ***,the fusion of the obtained results leads to a final traffic volume *** experimental results show that the proposed method outperforms other benchmarks regarding various evaluation measures,including mean absolute error,root mean squared error,mean absolute percentage error,and *** achieved R-squared value reaches an impressive 98%,while the other evaluation indices surpass the *** findings highlight the accuracy of traffic pattern ***,this offers promising prospects for enhancing transportation management systems and urban infrastructure planning.

关键词： Ensemble empirical mode decomposition traffic volume prediction long short-term memory optimal hyperparameters deep learning

Twisted fiber microfluidics:a cutting-edge approach to 3D spiral devices

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第1期10卷 193-202页

作者： shunsuke Kato Daniel W.Carlson Amy q.shen Yuanyuan Guo Department of Electrical Information and Physics EngineeringSchool of EngineeringTohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Micro/Bio/Nanofluidics Unit Okinawa Institute of Science and TechnologyOnnaKunigami-gun 904-0495 OkinawaJapan Frontier Research Institute for Interdisciplinary sciences(FRIs) Tohoku UniversityAoba-kuSendai 980-0845 MiyagiJapan Graduate school of Biomedical Engineering Tohoku UniversityAoba-kuSendai 980-8579 MiyagiJapan Department of Physiology Graduate School of MedicineTohoku UniversityAoba-kuSendai 980-8575 MiyagiJapan

The development of 3D spiral microfluidics has opened new avenues for leveraging inertial focusing to analyze small fluid volumes,thereby advancing research across chemical,physical,and biological *** traditional straight microchannels rely solely on inertial lift forces,the novel spiral geometry generates Dean drag forces,eliminating the necessity for external fields in fluid ***,fabricating 3D spiral microfluidics remains a labor-intensive and costly endeavor,hindering its widespread ***,conventional lithographic methods primarily yield 2D planar devices,thereby limiting the selection of materials and geometrical *** address these challenges,this work introduces a streamlined fabrication method for 3D spiral microfluidic devices,employing rotational force within a miniaturized thermal drawing process,termed as *** innovation allows for rapid prototyping of twisted fiber-based microfluidics featuring versatility in material selection and heightened geometric *** validate the performance of these devices,we combined computational modeling with microtomographic particle image velocimetry(uTPiM)to comprehensively characterize the 3D flow *** results corroborate the presence of a steady secondary flow,underscoring the effectiveness of our *** 3D spiral microfluidics platform paves the way for exploring intricate microflow dynamics,with promising applications in areas such as drug delivery,diagnostics,and lab-on-a-chip systems.

关键词： thereby straight twisted

A Preliminary Comparative study on the Centering Algorithms for CassiniIss NAC Images

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.Liang q.-F.Zhang G.-M.Liu W.-H.Zhu C.-s.Wang Department of Computer science Jinan UniversityGuangzhou 510632China sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China school of Computer science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow Angle Camera(NAC)of the Cassini Imaging science subsystem(Iss).selecting the best centering algorithm is key to enhancing astrometric *** this study,we compared the accuracy of five centering algorithms:Gaussian fitting,the modified moments method,and three point-spread function(PsF)fitting methods(effective PsF(ePsF),PsFEx,and extended PsF(x PsF)from the Cassini Imaging Central Laboratory for Operations(CICLOPs)).We assessed these algorithms using 70 Iss NAC star field images taken with CL1 and CL2 filters across different stellar *** ePsF method consistently demonstrated the highest accuracy,achieving precision below 0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PsF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPsF model provided by CICLOPs had lower precision than the ***,the ePsF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPsF focusing on photometry rather than *** findings highlight the necessity of constructing PsF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these Iss NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

Rare earth based MgPm_(2)X_(4)(X=s,se) spinel chalcogenides for spintronic and thermoelectric applications

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1577-1585,I0006页

作者： Tariq M.Al-Daraghmeh Omar Zayed Ghulam M.Mustafa Taharh Zelai Bisma Younas Hind Albalawi s.Bouzgarrou Othman Hakami q.Mahmood Khaild I.Hussein Basic sciences Department King Abdullah Ⅱ School of EngineeringPrincess Sumaya University For TechnologyP.O.Box 1438Al-jubaiha11941AmmanJordan Department of Physics Division of Science&TechnologyUniversity of EducationLahorePakistan Department of Physics Faculty of ScienceJazan University JazanSaudi Arabia Department of Physics The University of LahoreLahorePakistan Department of Physics College of SciencesPrincess Nourah bint Abdulrahman University(PNU)P.O.Box 84428Riyadh11671Saudi Arabia Department of Physics College of ScienceQassim UniversityPo.64BuraidahSaudi Arabia Laboratoire de Microelectronique et Instrumentation(UR 03/13-04) Faculte des Sciences de MonastirAvenue de I'Environnement 5000MonastirTunisia Department of Chemistry Faculty of ScienceJazan University JazanSaudi Arabia Basic&Applied scientific Research Center Department of PhysicsCollege of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam 31441Saudi Arabia Department of Radiological sciences College of Applied Medical SciencesKing Khalid UniversityAbha61421Saudi Arabia

In current report,the structural,magnetic,and thermoelectric properties of RE doped MgPm_(2)X_(4)(X=s,se) spinels were *** energy difference in ferromagnetic and antiferromagnetic states reveals the stability of MgPm_(2)(s/se)_(4) in the ferromagnetic *** co mputation of enthalpy of formation also ascertains thermodynamic stability of crystal ***-dependent band structure and density of states analysis reveal ferromagnetic semiconducting character showing different electronic behavior in both spin *** room temperature ferromagnetism,spin polarization and Curie temperature are estimated from exchange energies *** addition,exchange constants(N_(0)α and N_(0)β),exchange energy Δ_(x)(pd),crystal ifeld energy,and double exchange mechanism were studied to explore the magnetic ***,the electrical conductivity,thermal conductivity,seebeck co-efficient,and power factor show effect on electrons spin and their potential for thermoelectric devices.

关键词： Rare earth elements spintronic applications Thermoelectric effects Exchange energies

seismic and geological evidence of hidden faults in the Yinpan Reservoir area based on a dense seismic array

在线全文

学校读者我要写书评

暂无评论

science China Earth sciences 2024年第7期67卷 2401-2407页

作者： Guangyao YIN Huai ZHANG Liwen GONG q ipeng BAI Yicun GUO Bing ZHANG Yaolin sHI Key Laboratoryof Earth system Numerical Modeling and Application(Chinese Academyof sciences) College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Computational Geodynamics Chinese Academy of SciencesBeijing 100049China southern Marine science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Critical Zone National Field scientific Observation and Research station Beijing 101408China Chongqing Earthquake Agency Chongqing 401147 China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Hangzhou Applied Acoustics Research Institute Hangzhou 311100China state Key Laboratory of Geodesy and Earths Dynamics Innovation Academy for Precision Measurement Science and TechnologyCASWuhan 430077China

*** November 23,2017,an M_(s)5.0 earthquake occurred in Wulong,Chongqing,China,resulting in tens of casualties and considerable economic ***,the epicenter of this earthquake was located in the transition zone from the... 详细信息

关键词： earthquake southeast seismic