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国外煤田地质 1998年第4期 12-19页

作者： ghosh,tk 顾文浩

DESIGN OF A HIGH EFFICIENCY C-BAND 60W SPACE TWT

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DESIGN OF A HIGH EFFICIENCY C-BAND 60W SPACE TWT

An analytical approach for the fractional-order Hepatitis B model using new operator

1998 International Conference on Microwave and Millimeter Wave Technology

作者： V Srivastava B Ravinder tk ghosh D Choudhuri AK Sinha RS Raju SN Joshi Microwave Tubes Area Central Electronics Engineering Research Institute Pilani（Raj） India 333 031

＜正＞Design of a high efficiency C-band 60W space TWT is ***-house developed software packages are used for the design of:（i） electron gun,（ii） PPM focusing system,（iii） Helix SWS,（iv） Input ＆ Output Couplers,（v） Beam-refocussing section（BRS）,and（vi） multi-stage depressed collector（MDC）.Results are presented for the low-convergence electron gun with space-charge balanced flow;helix SWS with sever and double-velocity taper for high interaction efficiency;BRS for improving collector efficiency;and 4-stage depressed *** design is optimised at beam voltage 3.0kV and beam current *** electronic efficiency is achieved better than 32%and overall efficiency better than 55%.

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来源： cnki会议评论

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International Journal of Biomathematics 2024年第1期17卷 177-198页

作者： Surath ghosh Division of Mathematics School of Advanced Sciences Vellore Institute of TechnologyChennaiIndia

In this work,the main goal is to implement Homotopy perturbation transform method(HPTM)involving Katugampola fractional *** an example,a fractional order Hepatitis model is considered to analyze the *** first,the integer order model is converted to fractional order model in Caputo ***,the new operator Katugampola fractional derivative is used to present the *** new such kind of operator is illustrated in Caputo *** is described to get the solution of the proposed model using the new kind of ***,there are some analyses about the new kind of operator to prove the efficiency of the operator.

关键词： Caputo derivative Katugampola fractional derivative homotopy perturbation transform method Hepatitis B model

A NEWTON-TYPE GLOBALLY CONVERGENT INTERIOR-POINT METHOD TO SOLVE MULTI-OBJECTIVE OPTIMIZATION PROBLEMS

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Journal of Computational Mathematics 2024年第1期42卷 24-48页

作者： Jauny Prajapati Debdas ghosh Ashutosh Upadhayay Departmant of Mathematical Sciences Indian Institute of Technology(BHU)VaranasiUttar Pradesh 221005India

This paper proposes an interior-point technique for detecting the nondominated points of multi-objective optimization problems using the direction-based cone *** method decomposes the multi-objective optimization problems into a set of single-objective optimization *** this set of problems,parametric perturbed KKT conditions are ***,an interior point technique is developed to solve the parametric perturbed KKT conditions.A differentiable merit function is also proposed whose stationary point satisfies the KKT *** some mild assumptions,the proposed algorithm is shown to be globally *** results of unconstrained and constrained multi-objective optimization test problems are ***,three performance metrics(modified generational distance,hypervolume,inverted generational distance)are used on some test problems to investigate the efficiency of the proposed *** also compare the results of the proposed algorithm with the results of some other existing popular methods.

关键词： Cone method Interior point method Merit function Newton method Global convergence

Finite-time tracking control of heterogeneous multi-AUV systems with partial measurements and intermittent communication

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Science China(Information Sciences) 2024年第5期67卷 165-182页

作者： Bo CHEN Jiangping HU Bijoy Kumar ghosh School of Automation Engineering University of Electronic Science and Technology of China Key Laboratory of Intelligent Analysis and Decision on Complex Systems Chongqing University of Posts and Telecommunications Yangtze Delta Region Institute (Huzhou) University of Electronic Science and Technology of China Department of Mathematics and Statistics Texas Tech University

The development of a distributed trajectory-tracking control strategy that is independent of velocity measurements is critical to achieving finite-time tracking control of autonomous underwater vehicle(AUV) systems. In this study, a group of heterogeneous AUV systems with intermittent communication links is considered and a finite-time trajectory-tracking control strategy is developed. The strategy includes two observers and one controller proposed for each follower-AUV. The first observer, a hybrid finite-time observer,estimates the state of the leader, whereas the second observer, which relies only on the position measurement,is proposed to estimate the states of the follower-AUV itself. In addition, a distributed trajectory-tracking controller is designed using the states estimated by the intermittent communication network even without velocity measurements. A homogeneous technique is utilized to prove that all followers can track the leader in a finite time. Finally, the effectiveness of the developed finite-time tracking control strategy is illustrated by numerical simulations.

关键词： distributed observer finite-time tracking homogeneous technique intermittent communication multiple heterogeneous AUVs

Transient Stability Analysis of Grid-connected Converters in Wind Turbine Systems Based on Linear Lyapunov Function and Reverse-time Trajectory

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 782-790页

作者： Mohammad Kazem Bakhshizadeh Sujay ghosh Guangya Yang Łukasz Kocewiak Ørsted Wind Power A/S Nesa Allé12820Denmark Technical University of Denmark Anker Engelunds Vej 12800Denmark

As the proportion of converter-interfaced renewable energy resources in the power system is increasing,the strength of the power grid at the connection point of wind turbine generators(WTGs)is gradually *** research has shown that when connected with the weak grid,the stability of the traditional grid-following controlled converters will deteriorate,and they are prone to unstable phenomena such as *** to the limitations of linear analysis that cannot sufficiently capture the stability phenomena,transient stability must be *** far,standalone time-domain simulations or analytical Lyapunov stability criteria have been used to investigate transient ***,the time-domain simulations have proven to be computationally too heavy,while analytical methods are difficult to formulate for larger systems,require many modelling assumptions,and are often conservative in estimating the stability *** paper proposes and demonstrates an innovative approach to estimating the transient stability boundary via combining the linear Lyapunov function and the reverse-time trajectory *** proposed methodology eliminates the need of time-consuming simulations and the conservative nature of Lyapunov *** study brings out the clear distinction between the stability boundaries with different post-fault active current ramp rate *** the same time,it provides a new perspective on critical clearing time for wind turbine *** stability boundary is verified using time-domain simulation studies.

关键词： Lyapunov direct method non-autonomous system phase-locked loop(PLL) time trajectory reversal transient stability assessment wind turbine converter system

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Effect of metal fractions on rice grain metal uptake and biological parameters in mica mines waste contaminated soils

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Journal of Environmental Sciences 2024年第2期136卷 313-324页

作者： Saibal ghosh Sandip Mondal Jajati Mandal Abhishek Mukherjee Pradip Bhattacharyya Agricultural and Ecological Research Unit Indian Statistical InstituteGiridihJharkhand 815301India School of Science Engineering&EnvironmentUniversity of SalfordManchester M54WTUK

Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the *** present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice,soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand,*** each active mine,soil samples were randomly collected at distances of100 m(zone 3).Sequential metal extraction was used to determine the fractions of different metals(nickel(Ni),cadmium(Cd),chromium(Cr)and lead(Pb))including water-soluble(Ws)and exchangeable metals(Ex),carbonate-bound metals(CBD),Fe/Mn oxide(OXD)bound metals,organically bound metals(ORG),and residues(RS).The Ni,Cr,Cd and Pb in rice grain were 0.83±0.41,0.41±0.19,0.21±0.14 and 0.17±0.08 mg/kg *** the variable importance plot of the random forest(RF)algorithm,the Ws fraction of Ni,Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal ***,the partial dependence plots(PDP)give us an insight into the role of the two most important metal fractions on rice grain metal *** microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions,indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities.

关键词： Metal fractions Microbial parameters Mica waste soil Soil enzymes Rice Random forest

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Safe formation control of multiple unmanned aerial vehicles:control design and safety-stability analysis

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Control Theory and Technology 2024年第3期22卷 442-454页

作者： Haoqi Li Jiangping Hu Qingrui Zhou Bijoy K.ghosh School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731SichuanChina Yangtze Delta Region Institute(Huzhou) University of Electronic Science and Technology of ChinaHuzhou 313000ZhejiangChina Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China Department of Mathematics and Statistics Texas Tech UniversityLubbockTX 79409-1042USA

Both safety and stability are primary performance criteria for multi-unmanned aerial vehicle(multi-UAV)systems in many coordination *** approaches often consider safety and stability *** is necessary and urgent to develop a safety-stability control strategy to merge these two performance *** this paper,a unified approach is developed to consider safety and stability for multi-UAV formation *** stability criterion is represented by a Lyapunov function and safety criterion is represented by a barrier function and then a relaxed converse control Lyapunov-barrier theorem is *** the help of a relaxed converse control Lyapunov-barrier function(RCCLBF),a distributed safety-stability formation control strategy is proposed for the multi-UAV *** transforming the solution of RCCLBF to a Lyapunovlike stabilization problem,we show that the proposed formation control strategy can drive the UAVs staying within a specified safe *** results are provided to validate the proposed safety-stability formation control strategy.

关键词： Multi-UAV system Formation control Lyapunov function Barrier function Stability with safety guarantee

Dynamical system analysis of Dirac-Born-Infeld scalar field cosmology in coincident f(Q) gravity

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Chinese Physics C 2024年第9期48卷 203-213页

作者： Sayantan ghosh Raja Solanki P.K.Sahoo Department of Mathematics Birla Institute of Technology and Science-PilaniHyderabad Campus

In this article,we present a dynamical system analysis of a Dirac-Born-Infeld scalar field in a modified f(Q) gravity *** considered a polynomial form of modified gravity,used two different types of scalar potential,polynomial and exponential,and found a closed autonomous dynamical system of *** analyzed the fixed points of such a system and evaluated the conditions under which deceleration to late-time acceleration occurs in this *** note the similarity of the two models and show that our result is consistent with a previous study on Einstein s *** also investigated the phenomenological implications of our models by plotting EoS(ω),energy density(Ω),and deceleration parameter(q) *** e-fold time and comparing to the present *** conclude the paper by observing how the dynamical system analysis differs in the modified f(Q) gravity,and present the future scope of our research.

关键词： dark energy Dirac-Born-Infeld field dynamical system analysis f(Q) gravity

Impact of vaccination on the dynamics of COVID-19:A mathematical study using fractional derivatives

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International Journal of Biomathematics 2024年第2期17卷 201-232页

作者： Shraddha Ramdas Bandekar Mini ghosh C.Rajivganthi Division of Mathematics School of Advanced Sciences Vellore Institute of TechnologyChennaiIndia

Arrival of a new disease marks a yearlong destruction of human lives and economy in general,and if the disease turns out to be a pandemic the loss is ***-19 is one such pandemic that has claimed millions of lives till *** is a suffering throughout the world due to various factors associated with the pandemic,be it loss of livelihoods because of sudden shutdown of companies and lockdown,or loss of lives due to lack of medical aid and inadequate vaccination *** this study,we develop a six-compartmental epidemiological model incorporating *** motivation behind the study is to analyze the significance of higher vaccination efficacy and higher rate of population getting vaccinated in controlling the rise in infectives and thereby the untimely demise of various *** work begins with an ordinary differential equation model followed by stability analysis of the same,after which a fractional-order derivative model of the same is formulated and the existence of uniformly stable solution for the system is *** addition to this,we present the stability of the equilibria in general for the fractional model *** sensitivity analysis of the basic reproduction number along with its correlation with various parameters is *** addition to this,sensitivity of certain state variables in the fractional model with respect to *** orders as well with respect to different infection rate is exhibited in this *** related to lockdown and usage of face shields are incorporated in the entire study,and importance of these is highlighted in the study as *** major takeaway from the study is that mere vaccination will not sufice in eradication of the *** vaccine efficacy plays a major role along with other intervention included in the *** numerical simulations are carried out in MATLAB software using ode45 and fdel2.

关键词： Caputo fractional derivative basic reproduction number stability analysis sensitivityanalysis vaccination