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Journal of Rare Earths 2024年第1期42卷 46-56,I0002页

作者： L.Vijayalakshmi K.naveen kumar Jong Dae Baek Department of Automotive Engineering Yeungnam UniversityGyeongsanGyeongbuk38541Republic of Korea Department of Mechanical Engineering Yeungnam UniversityGyeongsan38541Republic of Korea

A set of co-doped(Tb^(3+)/Dy^(3+))lithium zinc borate(LZB)glasses were developed by melt *** structural evaluation was performed for synthesized glassy *** Dy^(3+)and Tb^(3+)individually doped glasses exhibit intense yellow and green luminescence bands at 575 nm(^(4)F_(9/2)→^(6)H_(13/2))and543 nm(^(5)D_(4)→^(7)F_(5)),*** sensitization effect of Dy^(3+)on Tb^(3+)was analyzed by increasing the Tb^(3+)content with respect to the optimum Dy^(3+)content(0.5 mol%)in Dy^(3+)/Tb^(3+).The spectral overlay of Dy^(3+)luminescence and Tb^(3+)absorption profiles,Dy^(3+)/Tb^(3+)PL spectra under different excitations 352,362,376,and 385 nm,shortening decay lifetimes of Dy^(3+)in Dy^(3+)/Tb^(3+)co-activated glasses,energy transfer(ET)parameters,chromaticity coordinates and their corresponding correlated temperatures all help to explain ET from Dy^(3+)to Tb^(3+).At 385 nm of Dy^(3+)excitation,the optimized co-activated(0.5Dy^(3+)+1.0Tb^(3+)):LZB glass displays cool white light *** non-radiative ET from Dy^(3+)to Tb^(3+)is dominated by electric dipole-dipole interaction and its ET efficiency was calculated to be 63%.At the same time,reverse ET from Tb^(3+)to Dy^(3+)was also *** shift in color coordinates from dominant yellow to greenish-yellow,green and white light emission suggests that Dy^(3+)/Tb^(3+)coactivated LZB glasses can be a potential candidate for UV converted multicolor and white light emitting devices.

关键词： Rare earths Photoluminescence Energy transfer Spectral overlap Decay lifetime Multicolor emitting LEDs

Strategy and Future Prospects to Develop Room-Temperature-Recoverable NO2 Gas Sensor Based on Two-Dimensional Molybdenum Disulfide

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Nano-Micro Letters 2021年第2期13卷 305-362页

作者： Abhay V.Agrawal naveen kumar Mukesh kumar Functional and Renewable Energy Materials Laboratory Indian Institute of Technology RoparRupnagarPunjab 140001India

Nitrogen dioxide(NO2),a hazardous gas with acidic nature,is continuously being liberated in the atmosphere due to human *** NO2 sensors based on traditional materials have limitations of high-temperature requirements,slow recovery,and performance degradation under harsh environmental *** limitations of traditional materials are forcing the scientific community to discover future alternative NO2 sensitive *** disulfide(MoS2)has emerged as a potential candidate for developing next-generation NO2 gas ***2 has a large surface area for NO2 molecules adsorption with controllable morphologies,facile integration with other materials and compatibility with internet of things(IoT)*** aim of this review is to provide a detailed overview of the fabrication of MoS2 chemiresistance sensors in terms of devices(resistor and transistor),layer thickness,morphology control,defect tailoring,heterostructure,metal nanoparticle doping,and through light ***,the experimental and theoretical aspects used in designing MoS2-based NO2 sensors are also discussed ***,the review concludes the challenges and future perspectives to further enhance the gas-sensing performance of *** and addressing these issues are expected to yield the development of highly reliable and industry standard chemiresistance NO2 gas sensors for environmental monitoring.

关键词： MoS2 NO2 gas sensors Light illumination Heterojunction

Effect of different geometrical non-uniformities on nonlinear vibration of porous functionally graded skew plates: A finite element study

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Defence Technology（防务技术） 2022年第6期18卷 918-936页

作者： H.S.naveen kumar Subhaschandra Kattimani Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkal575025India

This article presents the investigation of nonlinear vibration analysis of tapered porous functionally graded skew(TPFGS)plate considering the effects of geometrical non-uniformities to optimize the thickness in the structural *** TPFGS plate is analyzed considering linearly,bi-linearly,and exponentially varying *** plate’s effective material properties are tailor-made using a modified power-law distribution in which gradation varies along the thickness direction of the TPFGS *** the non-linear finite element formulation to develop the kinematic equation’s displacement model for the TPFGS plate is based on the first-order shear deformation theory(FSDT)in conjunction with von Karman’s *** nonlinear governing equations are established by Hamilton’s *** direct iterative method is adopted to solve the nonlinear mathematical relations to obtain the nonlinear *** influence of the porosity distributions and porosity parameter indices on the nonlinear frequency responses of the TPFGS plate for different skew angles and variable thicknesses are studied for various geometrical *** influence of taper ratio,variable thickness,skewness,porosity distributions,gradation,and boundary conditions on the plate’s nonlinear vibration is *** nonlinear frequency analysis reveals that the geometrical nonuniformities and porosities significantly influence the porous functionally graded plates with varying thickness than the uniform ***,exponentially and linearly variable thicknesses can be considered for the thickness optimizations of TPFGS plates in the structural design.

关键词： Functionally graded material Shear deformation theory Porosity distributions Variable thickness Geometrical skewness Nonlinear free vibration

Security Attacks in Named Data Networking: A Review and Research Directions

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Journal of Computer Science & Technology 2019年第6期34卷 1319-1350页

作者： naveen kumar Ashutosh kumar Singh Abdul Aleem Shashank Srivastava Department of Computer Science and Engineering Motilal Nehru National Institute of Technology Allahabad Prayagraj 211004India

Contents such as audios,videos,and images,contribute most of the Internet traffic in the current *** content sharing is a tedious *** existing security solutions do not secure data but secure the communicating *** data networking(NDN)secures the data by enforcing the data publisher to sign the *** user can verify the data by using the public key of the *** is resilient to most of the probable security attacks in the TCP/IP model due to its new ***,new types of attacks are possible in *** article surveys the most significant security attacks in NDN such as interest flooding attacks,cache privacy attacks,cache pollution attacks,and content poisoning *** attack is classified according to their behavior and discussed for their detection techniques,countermeasures,and the affected *** article is an attempt to help new researchers in this area to gather the domain knowledge of *** article also provides open research issues that could be addressed by researchers.

关键词： named data networking(NDN) interest flooding attack cache privacy attack cache pollution attack content poisoning attack

Comprehensive evaluation of key management hierarchies for outsourced data

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Cybersecurity 2019年第1期2卷 150-166页

作者： naveen kumar Anish Mathuria Indian Institute of Information Technology VadodaraIndia Dhirubhai Ambani Institute of Information and Communication Technology GandhinagarIndia

Key management is an essential component of a cryptographic access control system with a large number of *** manages the secret keys assigned to the system entities in such a way that only authorized users can access a *** access control allows read access of a resource by the authorized users and disallows *** important objective of a key management is to reduce the secret key storage with each authorized *** this end,there exist two prominent types of key management hierarchy with single key storage per user used for read access control in data outsourcing scenario:user-based and *** this work,we analyze the two types of hierarchy with respect to static hierarchy characteristics and dynamic operations such as adding or revoking user *** analysis shows that the resource-based hierarchies can be a better candidate which is not given equal emphasis in the literature.A new heuristic for minimizing the key management hierarchy is introduced that makes it practical in use even for a large number of users and *** performance evaluation of dynamic operations such as adding or revoking a user’s read subscription is shown experimentally to support our analytical results.

关键词： Key management hierarchy Data outsourcing Access control

Influence of porosity distribution on nonlinear free vibration and transient responses of porous functionally graded skew plates

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Defence Technology（防务技术） 2021年第6期17卷 1918-1935页

作者： naveen kumar H S Subhaschandra Kattimani TNguyen-Thoi Department of Mechanical Engineering National Institute of Technology KarnatakaSurathkal575025India Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang University Ho Chi Minh CityViet Nam

This article deals with the investigation of the effects of porosity distributions on nonlinear free vibration and transient analysis of porous functionally graded skew(PFGS)*** effective material properties of the PFGS plates are obtained from the modified power-law equations in which gradation varies through the thickness of the PFGS plate.A nonlinear finite element(FE)formulation for the overall PFGS plate is derived by adopting first-order shear deformation theory(FSDT)in conjunction with von Karman’s nonlinear strain displacement *** governing equations of the PFGS plate are derived using the principle of virtual *** direct iterative method and Newmark’s integration technique are espoused to solve nonlinear mathematical *** influences of the porosity distributions and porosity parameter indices on the nonlinear frequency responses of the PFGS plate for different skew angles are studied in various *** effects of volume fraction grading index and skew angle on the plate’s nonlinear dynamic responses for various porosity distributions are illustrated in detail.

关键词： Porous functionally graded skew plates Porosity distributions Nonlinear transient response Nonlinear frequency ratio Nonlinear frequency parameter

Does weather affect the growth rate of COVID-19,a study to comprehend transmission dynamics on human health

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Journal of Safety Science and Resilience 2020年第1期1卷 3-11页

作者： Arjun Sil Vanapalli naveen kumar Dept of Civil Engineering NIT SilcharAssam 788010India

The undefendable outbreak of novel coronavirus(SARS-COV-2)lead to a global health emergency due to its higher transmission rate and longer symptomatic duration,created a health surge in a short *** Nov 2019 the outbreak in China,the virus is spreading exponentially *** current study focuses on the relationship between environmental parameters and the growth rate of *** statistical analysis suggests that the temperature changes retarded the growth rate and found that-6.28℃ and+14.51℃ temperature is the favorable range for COVID-19 ***-Richter’s relationship is used to estimate the mean daily rate of exceedance of confirmed cases concerning the change in ***,temperature is the most influential parameter that reduces the growth at the rate of 13-17 cases/day with a 1℃ rise in temperature.

关键词： Covid-19 Pendemic Temperature Health risk

Computational Fluid Dynamics Study of a Compound Flow Field for Proton Exchange Membrane Fuel Cell(PEMFC) Performance Enhancement

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Journal of Thermal Science 2022年第6期31卷 2374-2384页

作者： Venkateswarlu VELISALA Gandhi PULLAGURA naveen kumar CHINNAM Raju GANTA Automobile Engineering Section Damacharla Anjaneyulu Government PolytechnicOngole 523002Andhra PradeshIndia GITAM Institute of Technology Visakhapatnam 530045Andhra PradeshIndia Vishnu Institute of Technology Bhimavaram 534202Andhra PradeshIndia BVC Engineering College Odalarevu 533210Andhra PradeshIndia

The aim of the present work is to evaluate proton exchange membrane(PEM) fuel cell performance with a modified serpentine flow field with right angle turn by numerical modeling. A 3-D PEM fuel cell model of size 50 cm^(2) active area is developed. A conventional serpentine flow field is modified and the same is considered for the supply of reactants. Computational fluid dynamics(CFD) based simulations were conducted to analyse the pressure drop, distribution of reactants(H_(2) and O_(2)), liquid water activity, current flux density and water content in the membrane. From the simulation results, polarization curve is drawn to validate the literature data of PEMFC with the conventional serpentine flow field. Comparison of simulated polarization curve with literature data revealed that modified serpentine flow field performance is better than conventional serpentine flow field as it offers better water exclusion and uniform sharing of reactants. From this study, it is concluded that model of flow field pattern influences the functioning of fuel cell and utmost care must take while selecting a pattern for flow field of PEM fuel cell.

关键词： PEM fuel cell CFD current density water removal modified serpentine flow field membrane water content

Ensemble Based Temporal Weighting and Pareto Ranking (ETP) Model for Effective Root Cause Analysis

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Computers, Materials & Continua 2021年第10期69卷 819-830页

作者： naveen kumar Seerangan S.Vijayaragavan Shanmugam Department of Computer Science(Category-B) Bharathiar UniversityCoimbatore641046Tamil NaduIndia CSE Muthayammal Engineering CollegeRasipuram637408Tamil NaduIndia

Root-cause identification plays a vital role in business decision making by providing effective future directions for the *** extraction and sentiment extraction plays a vital role in identifying the *** paper proposes the Ensemble based temporal weighting and pareto ranking(ETP)model for Root-cause *** extraction is performed based on rules and is followed by opinion identification using the proposed boosted ensemble *** obtained aspects are validated and ranked using the proposed aspect weighing ***-rule based aspect selection is performed as the final selection mechanism and the results are presented for business decision *** were performed with the standard five product benchmark *** on all five product reviews indicate the effective performance of the proposed *** are performed using three standard state-of-the-art models and effectiveness is measured in terms of F-Measure and Detection *** results indicate improved performances exhibited by the proposed model with an increase in F-Measure levels at 1%–15%and detection rates at 4%–24%compared to the state-of-the-art models.

关键词： Root cause analysis sentiment analysis aspect extraction ensemble modelling temporal weighting pareto ranking

Bibliometric analysis of Blockchain in the healthcare domain

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Intelligent and Converged Networks 2023年第4期4卷 305-312页

作者： Shilpi Garg Rajesh kumar Kaushal naveen kumar Anshul Verma Chitkara Institute of Engineering and Technology Chitkara UniversityPunjab 140401India Institute of Science Banaras Hindu UniversityVaranasi 221005India

As an innovation,Blockchain has transformed numerous industries and sparked the interest of the research community due to its abundance of benefits,opening up diverse research routes in the healthcare sector in the last *** Health 4.0 becoming ubiquitous in the healthcare industry,end-user transactions are being carried out on a decentralized network,making Blockchain profitable to meet the demands of the modern healthcare ***,a detailed analysis of Blockchain is very *** study emphasizes the evolution of science and the preliminary research of Blockchain in healthcare through bibliometric *** the data are extracted from the Scopus database,and the VOSviewer tool is used for analysis.A total of 1152 Scopus articles published between 2018 and 2022 are *** reveal that in 2022,the field of Blockchain experienced a notable increment in the number of publications and a significant growth *** Access became well known in this field and had a large number of *** is observed that China and India are the leading countries in terms of publications on *** study offers a number of recommendations that amateur and professional researchers can use as a benchmark before commencing a Blockchain investigation in the future.

关键词： Blockchain bibliometric healthcare VOSviewer