检索结果-南通市图书馆

Quasinormal modes and late time tails of perturbation fields on a Schwarzschild-like black hole with a global monopole in the Einstein-bumblebee theory

引用

Science China(Physics,Mechanics & Astronomy) 2023年第10期66卷 33-43页

作者： Xiaolin Zhang Mengjie Wang Jiliang Jing School of Physics and Electronics Synergetic Innovation Center for Quantum Effects and Applicationsand Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha 410081China

In this paper we complete a systematic study on quasinormal modes(QNMs) and late time tails for scalar,Dirac and Maxwell fields on a spherically symmetric Schwarzschild-like black hole with a global monopole in the Einstein-bumblebee *** look for QNMs,we solve the equations of motion for all perturbation fields considered herein numerically,by employing both the matrix and the WKB methods,and find good agreements for numeric data obtained by these two techniques in the regime when both are *** impact of the bumblebee parameter c,the monopole parameter η^(2),and the multipole number l on the fundamental quasinormal frequency are analyzed in *** results are shown in terms of the quasinormal frequency measured by √1+c M ,where M is a black hole mass *** observe,by increasing the parameter c(η^(2)) with fixed first few l,that the real part of QNMs increases for all spin fields;while the magnitude of the imaginary part decreases for scalar and Dirac fields but increases for Maxwell *** increasing the multipole numberlwith fixed other parameters,we disclose that the real part of QNMs for all spin fields increases while the magnitude of the imaginary part decreases for scalar and Dirac fields but increases for Maxwell *** the eikonal limit(l>>n),QNMs for all spin fields coincide with each other and the real part scale linearly with *** particular,the asymptotic QNMs approach the corresponding results given by the first order WKB formula,and only the real part of QNMs is dependent on the bumblebee and monopole *** addition,it is shown that the late time behavior is determined not only by the multipole number but also by the bumblebee and monopole parameters,and is distinct for bosonic and fermonic ***,the presence of the bumblebee(monopole) field makes the spin fields decay *** results indicate,both in the context of QNMs and late time tails,that the bumblebee field and the monopole field play the same ro

关键词： Einstein-bumblebee theory perturbation fields dynamic evolution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Detailed analysis of fan-shaped jets in three dimensional numerical simulation

引用

Research in Astronomy and Astrophysics 2011年第6期11卷 701-724页

作者： Rong-Lin Jiang K.Shibata H.Isobe Cheng Fang Department of Astronomy Nanjing UniversityNanjing 210093China Kwasan and Hida Observatories Kyoto UniversityYamashinaKyoto 607-8471Japan unit of synergetic studies for space Kyoto UniversityYamashinaKyoto 607－8471Japan Key Laboratory of Modern Astronomy and Astrophysics（Nanjing University） Ministry of EducationNanjing 210093China

We performed three dimensional resistive magnetohydrodynamic simulations to study the magnetic reconnection using an initially shearing magnetic field configuration（force free field with a current sheet in the middle of the computational box）.It is shown that there are two types of reconnection jets：the ordinary reconnection jets and fan-shaped jets,which are formed along the guide magnetic *** fan-shaped jets are significantly different from the ordinary reconnection jets which are ejected by magnetic tension *** are two driving forces for accelerating the fan-shaped *** is the Lorentz force which initially dominates the motion of fluid elements,and then the gas pressure gradient force accelerates the fluid elements in the later *** dependence on magnetic reconnection angle and resistivity value has also been *** formation and evolution of these jets provide a new understanding of dynamic magnetohydrodynamic jets.

关键词： magnetohydrodynamics MHD-methods numerical

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Constitutionally adaptive crown ether-based macrocyclic bolaamphiphile with redox-responsive switching of lower critical solution temperature behaviors

引用

Chinese Chemical Letters 2021年第12期32卷 4024-4028页

作者： Qiangqiang Xu Zhiliyu Cui Jizhen Yao Bo Li Ping Lv Xin Shen Zhuo Yu Yan Ge Zhenhui Qi Sino-German Joint Research Lab for space Biomaterials and Translational Technology Synergetic Innovation Center of Biological Optoelectronics and Healthcare Engineering(BOHE)Xi'an 710072China

Constitutionally adaptive chemistry of selenium-containing crown ethers(CEs) offers a new platform for controlling/switching the hydration of bolaamphiphile skeletons in water in an effective and simple manner by the virtue of covalent bonding. The adaptive behaviour of the macrocyclic bolaamphiphiles(transformations between C7SeBola and C7SeOBola) in response to redox environment was found to be a decisive factor.

关键词： Macrocycle Crown ether Bola Amphiphiles Selenium

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Upper ocean high resolution regional modeling of the Arabian Sea and Bay of Bengal

引用

Acta Oceanologica Sinica 2019年第5期38卷 32-50页

作者： Dwivedi Suneet Mishra Alok Kumar Srivastava Atul K Banerjee Centre of Atmospheric and Ocean studies and M N Saha Centre of space studies University of Allahabad

In this paper, effort is made to demonstrate the quality of high-resolution regional ocean circulation model in realistically simulating the circulation and variability properties of the northern Indian Ocean(10°S–25°N,45°–100°E) covering the Arabian Sea(AS) and Bay of Bengal(BoB). The model run using the open boundary conditions is carried out at 10 km horizontal resolution and highest vertical resolution of 2 m in the upper *** surface and sub-surface structure of hydrographic variables(temperature and salinity) and currents is compared against the observations during 1998–2014(17 years). In particular, the seasonal variability of the sea surface temperature, sea surface salinity, and surface currents over the model domain is studied. The highresolution model's ability in correct estimation of the spatio-temporal mixed layer depth(MLD) variability of the AS and BoB is also shown. The lowest MLD values are observed during spring(March-April-May) and highest during winter(December-January-February) seasons. The maximum MLD in the AS(BoB) during December to February reaches 150 m (67 m). On the other hand, the minimum MLD in these regions during March-April-May becomes as low as 11–12 m. The influence of wind stress, net heat flux and freshwater flux on the seasonal variability of the MLD is discussed. The physical processes controlling the seasonal cycle of sea surface temperature are investigated by carrying out mixed layer heat budget analysis. It is found that air-sea fluxes play a dominant role in the seasonal evolution of sea surface temperature of the northern Indian Ocean and the contribution of horizontal advection, vertical entrainment and diffusion processes is small. The upper ocean zonal and meridional volume transport across different sections in the AS and BoB is also computed. The seasonal variability of the transports is studied in the context of monsoonal currents.

关键词： Indian Ocean modeling Arabian Sea and Bay of Bengal mixed layer depth transport

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Alpha/proton Instability in the Presence of Proton and Alpha Temperature Anisotropy and its Application to the Deceleration of Alpha Particles in the Solar Wind

引用

Research in Astronomy and Astrophysics 2022年第1期22卷 192-204页

作者： Wen-Lu Zhang Liang Xiang Qiu-Huan Li Si-Yi Lang Hong-Wei Yu Department of Physics and synergetic Innovation Center for Quantum Effects and Applications School of Physics and ElectronicsHunan Normal UniversityChangsha 410081China Institute of space Physics Luoyang Normal UniversityLuoyang 471934China

Observations of solar wind plasma find that the drift velocity between alpha beams and protons,vα,is reduced with the heliocentric distance,but the ratio of vαto vA(the local Alfven velocity)does not vary obviously and has a typical velocity ratio of vα/vA≤*** alpha beam instability is believed to be responsible for the deceleration of alpha beams in the solar ***,the role of the temperature anisotropy of ions(protons and alpha particles)on the alpha beam instability has not been *** on the kinetic theory of the PDRK solver,this study systemically investigates the alpha beam instability in the presence of proton and alpha temperature anisotropies and considers the effects of these temperature anisotropies on the instability at an arbitrary propagation angle relative to the ambient magnetic *** is found that the real frequencies,growth rates and threshold conditions of the excited waves sensitively depend on the proton temperature anisotropy T_(i⊥)/T_(i‖)and the alpha temperature anisotropy T_(α⊥)/T_(α‖),as well as the parallel electron betaβe‖.In particular,for both alpha beam and proton temperature anisotropy driven cases,the parallel magnetosonic/whistler(PM/W),backward magnetosonic/whistler(BM/W)and oblique Alfvén/ion cyclotron(OA/IC)waves arise when T_(i⊥)/T_(i‖)*** presence of anisotropic protons leads to a lower velocity threshold for the OA/IC and BM/W waves at T_(i⊥)/T_(i‖)*** both alpha beam and alpha temperature anisotropy driven cases,the PM/W and OA/IC waves are unstable when T_(α⊥)/T_(α‖)*** presence of anisotropic alpha particles results in a lower threshold velocity for the PM/W wave at T_(α⊥)/T_(α‖)<1 and for the PA/IC,OM/W and mirror waves at T_

关键词： (Sun:)solar wind Sun:heliosphere waves

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Impact of Brunswick River Mouth Training Walls on Adjacent Beaches,Brunswick Heads,New South Wales,Australia

引用

海洋工程：英文版 2004年第2期18卷 207-220页

作者：黄海军 Andrew D.SHORT Thomas ZENG David HANSLOW Institute of Oceanology Coastal studies unit Department of Land and Water Conservation

River training walls have been built at scores of locations along the NSW coast and their impacts on shoreline change are still not fully understood. In this study, the Brunswick River entrance and adjacent beaches are selected for examination of the impact of the construction of major training walls. Thirteen sets of aerial photographs taken between 1947 and 1994 are used in a GIS approach to accurately determine the shoreline position, beach contours and sand volumes, and their changes in both time and space, and then to assess the contribution of both the structures and natural hydrodynamic conditions to large scale (years-decades and kilometres) beach changes. The impact of the training walls can be divided into four stages: natural conditions prior to their construction (pre 1959), major downdrift erosion and updrift accretion during and following the construction of the walls in 1959～1962 and 1966, diminishing impact of the walls between 1966 and 1987, and finally no apparent impact between 1987～1994. The impact extends horizontally about 8 km updrift and 17 km downdrift, and temporally up to 25 years.

关键词： human structure beach erosion and accretion beach downdrift/updrift shoreline change GIS

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chiral bound states in a staggered array of coupled resonators

引用

Chinese Physics B 2024年第2期33卷 124-130页

作者：金伍林李静卢竞龚志瑞周兰 synergetic Innovation Center for Quantum Effects and Applications Key Laboratory for Matter Microstructure and Function of Hunan ProvinceKey Laboratory of Low-Dimensional Quantum Structures and Quantum Control of the Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesXiangjiang-Laboratory and Department of PhysicsHunan Normal UniversityChangsha 410081China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent *** addition to the two typical bound states found above and below the energy bands,this system presents an extraordinary chiral bound state located within the energy *** use the chirality to quantify the breaking of the mirror *** find that the chirality value undergoes continuous changes by tuning the coupling *** preferred direction of the chirality is controlled not only by the competition between the intracell and the intercell hoppings in the coupled-resonator array,but also by the coherence between the two coupling *** the case with one coupling point,the chirality values varies monotonously with difference between the intracell hopping and the intercell *** in the case with two coupling points,due to the coherence between the two coupling points the perfect chiral states can be obtained.

关键词： bound states two-level small atom coupled-resonator array chirality

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantized Redshift and its Significance for Recent Observation

引用

Research in Astronomy and Astrophysics 2024年第9期24卷 156-166页

作者： Arindam Mal Sarbani Palit Christopher C.Fulton Sisir Roy Indian space Research Organization Space Applications CentreAhmedabadIndia Indian Statistical Institute CVPR UnitKolkataIndia Protostar Inc.15652 Carrousel DriveCanyon CountryCA 91387USA National Institute of Advanced studies IISC CampusBangaloreIndia

With the recent observational evidence in extragalactic astronomy,the interpretation of the nature of quasar redshift continues to be a research *** high redshifts are being detected for extragalactic objects that are presumably very distant and young while also exhibiting properties that are characteristic of a more mature galaxy such as *** to Halton Arp and Geoffrey Burbidge,redshift disparities consist of an intrinsic component and are related to an evolutionary *** observed redshift periodicity at integer multiples of0.089 in log scale and Burbidge observed redshift periodicity at integer multiples of 0.061 in linear *** Singular Value Decomposition based periodicity estimation is known to be superior for noisy data sets,especially when the data contain multiple harmonics and overtones,mainly irregular in nature,we have chosen it to be our primary tool for analysis of the quasar-galaxy pair redshift *** have observed a fundamental periodicity of0.051 with a confidence interval of 95%in linear scale with the site-available Sloan Digital Sky Survey Data Release 7(SDSS DR7)quasar-galaxy pair data *** have independently generated quasar-galaxy pair data sets from both 2d F and SDSS and found fundamental periodicities of 0.077 and 0.089,respectively,in log scale with a confidence interval of 95%.

关键词： galaxies:distances and redshifts (galaxies:)quasars:absorption lines cosmology:observations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

REKF and RUKF for pico satellite attitude estimation in the presence of measurement faults

引用

Journal of Systems Engineering and Electronics 2014年第2期25卷 288-297页

作者： Halil Ersin Sken Chingiz Hajiyev Department of space and Astronautical Science The Graduate University for Advanced Studies (Sokendai) Aeronautics and Astronautics Faculty Istanbul Technical University

When a pico satellite is under normal operational condi- tions, whether it is extended or unscented, a conventional Kalman filter gives sufficiently good estimation results. However, if the measurements are not reliable because of any kind of malfunc- tions in the estimation system, the Kalman filter gives inaccurate results and diverges by time. This study compares two different robust Kalman filtering algorithms, robust extended Kalman filter （REKF） and robust unscented Kalman filter （RUKF）, for the case of measurement malfunctions. In both filters, by the use of de- fined variables named as the measurement noise scale factor, the faulty measurements are taken into the consideration with a small weight, and the estimations are corrected without affecting the characteristic of the accurate ones. The proposed robust Kalman filters are applied for the attitude estimation process of a pico satel- lite, and the results are compared.

关键词： pico satellite attitude estimation robust Kalman filter-ing extended Kalman filter (EKF) unscented Kalman filter (UKF).

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Stagnation temperature effect on the conical shock with application for air

引用

Chinese Journal of Aeronautics 2018年第4期31卷 672-697页

作者： Toufik ELAICHI Toufik ZEBBICHE Aeronautical Sciences Laboratory Institute of Aeronautics and Space Studies University SAAD Dahlab of Blida 1B.P.270

The aim of this work is to realize a new numerical program based on the development of a mathematical model allowing determining the parameters of the supersonic flow through a conical shock under hypothesis at high temperature, in the context of correcting the perfect gas model. In this case, the specific heat at constant pressure does not remain constant and varies with the increase of temperature. The stagnation temperature becomes an important parameter in the *** mathematical model is presented by the numerical resolution of a system of first-order nonlinear differential equations with three coupled unknowns for initial conditions. The numerical resolution is made by adapting the higher order Runge Kutta method. The parameters through the conical shock can be determined by considering a new model of an oblique shock at high temperature. All isentropic parameters of after the shock flow depend on the deviation of the flow from the transverse direction. The comparison of the results is done with the perfect gas model for low stagnation temperatures, upstream Mach number and cone deviation angle. A calculation of the error is made between our high temperature model and the perfect gas model. The application is made for air.

关键词： Calorically imperfect gas Conical shock High temperature Numerical integration Oblique shock Perfect gas model Runge Kutta method Supersonic flow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：