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

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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

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Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of rare Earths 2024年第1期42卷 66-75页

作者： s.w.wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil University

we investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence sensitizer rare earths

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Inflow and outflow permeability tests in a very soft clay under low stresses

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Journal of rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3270-3283页

作者： J.w.s.Vargas F.A.B.Danziger F.r.Lopes T.Lunne Federal University of rio de Janeiro Rio de JaneiroBrazil Norwegian Geotechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the BAT probe at sarapuíII soft clay test site are presented.A description of the BAT permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low *** pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe *** show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading *** sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests *** are presented concerning the relationship between index parameters and the in situ coefficient of permeability for sarapuíII clay,which plot outside the range of existing databases.

关键词： Permeability test soft clay BAT probe Inflow and outflow tests

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superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong s.w.Lee w.J.Kim Department of Materials science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy superplasticity severe plastic deformation Grain size Grain growth

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FEA-based Geometrical Modification of switched reluctance Motor for radial Force reduction

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Chinese Journal of Electrical Engineering 2024年第1期10卷 124-135页

作者： rani s Jayapragash r school of Electrical Engineering Vellore Institute of TechnologyChennai 600127India

switched reluctance motors(srMs)are becoming increasingly popular in the automotive sector owing to their robust ***,srMs are preferred particularly for EV applications owing to their fault tolerance,magnet-free structure,and high power/torque *** main concerns of srM compared to other machines include torque ripple and *** primary cause of vibration is the radial force created by the srM.A geometry-based modification of the srM to reduce the radial force without significantly changing the average torque produced is *** primary goal is to design a 4-phase,8/6 srM with a lower radial *** possible geometrical alterations are proposed:one with square windows and the other with circular holes on the rotor *** windows are sized and positioned to avoid flux *** criteria are developed for the optimal window size and *** element analysis(FEA)modelling of the srM is used to validate its *** FEA results are compared with the performance parameters obtained using the analytical *** the multiphysics design tool ANsYs to obtain the natural frequencies and associated deformations through modal *** to the conventional geometry,the radial force is significantly reduced by providing windows.

关键词： 8/6 srM radial force modal analysis FEA analysis natural frequencies srM with windows

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Kinematic analysis of flexible bipedal robotic systems

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 795-818页

作者： r.FAZEL A.M.sHAFEI s.r.NEKOO Department of Mechanical Engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

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Parametric investigation on the novel and cost-effective nano fly ash impregnated geopolymer system for sustainable construction

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Frontiers of structural and Civil Engineering 2024年第2期18卷 170-183页

作者： r.MOHANA s.M.Leela BHArATHI Department of Civil Engineering Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazardous environmental effects of greenhouse gas emissions and climate change demand alternative sources for cementitious materials in the construction *** development of geopolymer structures provides a way of producing 100%cement-free *** this research work,a novel and simple way of deriving nano particles from waste fly ash particles is *** effect of adding the synthesized nano fly ash particles as a filler medium in geopolymer mortars was investigated by considering strength and durability *** optimization was done by using regression analysis on the geopolymer mortar and the impact of adding nano fly ash particles was studied by varying different percentages of addition ranging from 0 to 7.5%by weight of binder *** the results,it was observed that 1%nano fly ash acted not only as a filler but also as nano-sized precursors of the polymerization process,resulting in denser geopolymer *** can explain the extraordinary gain in strength of 72.11 MPa as well as the denser core with negligible level of chloride ion penetration,making the material suitable for the development of structures susceptible to marine environment.

关键词： geopolymer nano fly ash chloride ion penetration durability polymerization fillers

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Image splicing Forgery Detection Using Feature-Based of sonine Functions and Deep Features

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Computers, Materials & Continua 2024年第1期78卷 795-810页

作者： Ala’a r.Al-shamasneh rabha w.Ibrahim Department of Computer science College of Computer&Information SciencesPrince Sultan UniversityRiyadh11586Saudi Arabia Department of Computer science and Mathematics Lebanese American UniversityBeirut11022801Lebanon Department of Mathematics Mathematics Research CenterNear East UniversityNicosia99138Turkey Information and Communication Technology research Group Scientific Research CenterAlayen UniversityDhi Qar64001Iraq

The growing prevalence of fake images on the Internet and social media makes image integrity verification a crucial research *** of the most popular methods for manipulating digital images is image splicing,which involves copying a specific area from one image and pasting it into *** were made to mitigate the effects of image splicing,which continues to be a significant research *** study proposes a new splicing detectionmodel,combining sonine functions-derived convex-based features and deep *** stages make up the proposed *** first step entails feature extraction,then classification using the“support vector machine”(sVM)to differentiate authentic and spliced *** proposed sonine functions-based feature extraction model reveals the spliced texture details by extracting some clues about the probability of image *** proposed model achieved an accuracy of 98.93% when tested with the CAsIA V2.0 dataset“Chinese Academy of sciences,Institute of Automation”which is a publicly available dataset for forgery *** experimental results show that,for image splicing forgery detection,the proposed sonine functions-derived convex-based features and deep features outperform state-of-the-art techniques in terms of accuracy,precision,and ***,the obtained detection accuracy attests to the benefit of using the sonine functions alongside deep feature *** the regions or locations where image tampering has taken place is limited by the *** research will need to look into advanced image analysis techniques that can offer a higher degree of accuracy in identifying and localizing tampering regions.

关键词： Image forgery image splicing deep learning sonine functions

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An Intelligent sDN-IoT Enabled Intrusion Detection system for Healthcare systems Using a Hybrid Deep Learning and Machine Learning Approach

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China Communications 2024年第10期21卷 267-287页

作者： r Arthi s Krishnaveni sherali Zeadally Computational Intelligence School of ComputingSRMISTKattankulathurChennaiIndia College of Communication and Information University of KentuckyUSA

The advent of pandemics such as COVID-19 significantly impacts human behaviour and lives every ***,it is essential to make medical services connected to internet,available in every remote location during these ***,the security issues in the Internet of Medical Things(IoMT)used in these service,make the situation even more critical because cyberattacks on the medical devices might cause treatment delays or clinical ***,services in the healthcare ecosystem need rapid,uninterrupted,and secure *** solution provided in this research addresses security concerns and services availability for patients with critical health in remote *** research aims to develop an intelligent software Defined Networks(sDNs)enabled secure framework for IoT healthcare *** propose a hybrid of machine learning and deep learning techniques(DNN+sVM)to identify network intrusions in the sensor-based healthcare *** addition,this system can efficiently monitor connected devices and suspicious ***,we evaluate the performance of our proposed framework using various performance metrics based on the healthcare application *** experimental results show that the proposed approach effectively detects and mitigates attacks in the sDN-enabled IoT networks and performs better that other state-of-art-approaches.

关键词： deep neural network healthcare intrusion detection system IoT machine learning software-defined networks

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An Efficient Modelling of Oversampling with Optimal Deep Learning Enabled Anomaly Detection in streaming Data

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China Communications 2024年第5期21卷 249-260页

作者： r.rajakumar s.sathiya Devi srinivasa ramanujan Centre SASTRA Deemed UniversityKumbakonamTamil Nadu 612001India University College of Engineering BIT CampusAnna UniversityTiruchirappalli 620024India

recently,anomaly detection(AD)in streaming data gained significant attention among research communities due to its applicability in finance,business,healthcare,education,*** recent developments of deep learning(DL)models find helpful in the detection and classification of *** article designs an oversampling with an optimal deep learning-based streaming data classification(Os-ODLsDC)*** aim of the OsODLsDC model is to recognize and classify the presence of anomalies in the streaming *** proposed Os-ODLsDC model initially undergoes preprocessing *** streaming data is unbalanced,support vector machine(sVM)-synthetic Minority Over-sampling Technique(sVM-sMOTE)is applied for oversampling ***,the Os-ODLsDC model employs bidirectional long short-term memory(Bi LsTM)for AD and ***,the root means square propagation(rMsProp)optimizer is applied for optimal hyperparameter tuning of the Bi LsTM *** ensuring the promising performance of the Os-ODLsDC model,a wide-ranging experimental analysis is performed using three benchmark datasets such as CICIDs 2018,KDD-Cup 1999,and NsL-KDD datasets.

关键词： anomaly detection deep learning hyperparameter optimization oversampling sMOTE streaming data

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