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Synthesis and spectroscopic investigations of trivalent europium- doped Z_(2)Si_(3)O_(8)(Z = Mg, Ca and Sr) nanophosphors for display applications

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Rare Metals 2021年第9期40卷 2610-2617页

作者： suman sheoran Kuldeep Singh Vijeta Tanwar Sitender Singh Anura Samantilleke Devender Singh Department of Chemistry Maharshi Dayanand UniversityRohtak 124001India Centro de Fisica Universidade of MinhoBraga 4710057Portugal

To explore the silicate lattice-based nanophosphors, a series of Eu3+-doped Z_(2)Si_(3)O_(8)(Z = Mg, Ca and Sr) materials were prepared by sol–gel procedure. The metal nitrates and silica powder were used as precursor components for the synthesis of these luminescent materials. Photoluminescence(PL) emission spectra, powder X-ray diffraction(PXRD), energy-dispersive X-ray spectroscopy(EDS), Fourier transform infrared spectroscopy(FTIR) and transmission electron microscopy(TEM)spectroscopic techniques were applied for the characterization of the fabricated materials. Three peaks were observed at 589, 613 and 650–652 nm corresponding to ^(5)D_(0)→^(7)F_(1-3) transition in PL emission spectra. Upon395 nm excitation and at 0.03 mol Eu3+, these nanophosphors displayed optimum photoluminescence with the most intense peak analogous to ^(5)D_(0)→^(7)F_(2)transition of dopant ion. The as-prepared phosphor materials were re-heated at1050 and 1150 ℃ to observe the consequences of higher temperatures on the emission intensity and crystal *** analysis confirmed that all the synthesized materials were of crystalline nature, and the crystallinity was observed to be improved by increasing the temperature. In the FTIR spectrum, peaks at 483 and 610 cm^(-1) proved the existence of SiO_(4)group in Ca_(2)Si_(3)O_(8), and the peak centered at 417 cm^(-1) confirmed the presence of MgO6 octahedral in Mg_(2)Si_(3)O_(8) materials. TEM images were used to determine the particle size(13–35 nm) and to study the threedimensional structure of nanophosphor materials. The experimental studies indicate that these materials may be promising as red-emitting nanophosphors for white lightemitting diodes.

关键词： Z_(2)Si_(3)O_(8) Nanophosphors Sol–gel Photoluminescence Crystalline

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Down-conversion characteristics of Eu3+ doped M2Y2Si2O9(M=Ba, Ca, Mg and Sr) nanomaterials for innovative solar panels

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Progress in Natural Science:Materials International 2019年第4期29卷 457-465页

作者： suman sheoran Vachan Singh Sitender Singh Sonika Kadyan Jasbir Singh Devender Singh Department of Chemistry Maharshi Dayanand University Department of Physics Government College

Down-conversion properties of Eu3+doped M2Y2Si2O9(M=Ba,Ca,Mg,Sr) phosphors have been investigated in *** phosphors were synthesized via the simple,fast and cost-effective sol-gel technique at a temperature of 950℃.Color coordinates and emission color can be altered by the varying concentration of dopant ion in *** luminescence intensity was obtained when doping 0.03 mol of Eu3+*** the excitation wavelength of 395 nm,these silicates showed strong red color,pure and sharp spectral peaks in visible region due to ~5 D0→F1-3transitions of Eu3+present in the *** of reaction temperature on luminescence was also analyzed for these *** sharp peaks in the X-ray diffraction pattern indicated the high crystallinity of prepared ***2Y2Si2O9has shown an orthorhombic crystal *** FTIR results confirmed the metal-oxygen vibrational modes available in the range of 400-1600 *** electron microscopy images have revealed that the variation of alkaline earth metal provided a very different crystal *** down conversion response of these phosphor materials can provide a great significance in the application of the coming solar devices.

关键词： M2Y2Si2O9:Eu3+ Phosphor Sol-gel Lattice Solar devices

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Impact of selection of DC base values and DC link control strategies on sequential AC-DC power-flow convergence

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Frontiers in Energy 2015年第4期9卷 399-412页

作者： Shagufla KHAN suman BHOWMICK Department of Electrical Engineering Delhi Technological University Delhi 110042 India

This paper demonstrates the convergence of the integrated AC-DC power-flow algorithm as affected by the selection of different base values for the DC quantities and adoption of different control strategies for the DC link. For power-flow modeling of integrated AC-DC systems, the base values of the various DC quantities can be defined in several ways, giving rise to different sets of per-unit system equations. It is observed that different per-unit system models affect the convergence of the power-flow algorithm differently. In a similar manner, the control strategy adopted for the DC link also affects the power- flow convergence. The sequential method is used to solve the DC variables in the Newton Raphson （NR） power flow model, where AC and DC systems are solved separately and are coupled by injecting an equivalent amount of real and reactive power at the terminal AC buses. Now, for a majority of the possible control strategies, the equivalent real and reactive power injections at the concerned buses can be computed a-priori and are independent of the NR iterative loop. However, for a few of the control strategies, the equivalent reactive power injections cannot be computed a-priori and need to be computed in every NR iteration. This affects the performance of the iterative process. Two different per-unit system models and six typical control strategies are taken into consideration. This is validated by numerous case studies conducted on the IEEE 118-bus and 300-bus test systems.

关键词： AC-DC power-flow Newton-Raphsonmethod high voltage direct current (HVDC) controlstrategy

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Hybrid Cuckoo Search Algorithm for Scheduling in Cloud Computing

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Computers, Materials & Continua 2022年第4期71卷 1641-1660页

作者： Manoj Kumar suman CSE Department DCR University of Science and TechnologyMurthal131039SonepatIndia

Cloud computing has gained widespread popularity over the last *** problem in cloud computing is prejudiced due to enormous demands of cloud ***-heuristic techniques in cloud computing have exhibited high performance in comparison to traditional scheduling *** paper presents a novel hybrid Nesterov Accelerated Gradient-based Cuckoo Search Algorithm(NAGCSA)to address the scheduling issue in cloud *** Accelerated Gradient can address trapping at local minima in CSA by updating the position using future *** local search in the proposed algorithm is performed by using Nesterov Accelerated Gradient,while the global search is performed by using levy *** amalgamation of NAG and CSA helps in cost reduction and time-saving for *** simulation has been carried out on the CloudSim tool on three different real datasets;NASA,HPC2N,and *** results of the proposed hybrid algorithm have been compared with state-of-art scheduling algorithms(GA,PSO,and CSA),and statistical significance is carried on mean,standard deviation,and best for each *** has been established that the proposed algorithm minimizes the execution cost and makespan,hence enhancing the quality of service for users.

关键词： Cloud computing scheduling quality of service cuckoo search cost makespan

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Fuzzy Firefly Based Intelligent Algorithm for Load Balancing inMobile Cloud Computing

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Computers, Materials & Continua 2023年第1期74卷 1783-1799页

作者： Poonam suman Sangwan CSE Department Deenbandhu Chhotu Ram University of Science and TechnologyMurthal131039SonepatIndia

This paper presents a novel fuzzy firefly-based intelligent algorithm for load balancing in mobile cloud computing while reducing *** proposed technique implicitly acts intelligently by using inherent traits of fuzzy and *** automatically adjusts its behavior or converges depending on the information gathered during the search process and objective *** works for 3-tier architecture,including cloudlet and public *** cloudlets have limited resources,fuzzy logic is used for cloudlet selection using capacity and waiting time as *** provides human-like decisions without using any mathematical *** is a powerful meta-heuristic optimization technique to balance diversification and solution *** balances the load on cloud and cloudlet while minimizing makespan and execution ***,it may trap in local optimum;levy flight can handle *** of fuzzy fireflywith levy flight is a novel technique that provides reduced makespan,execution time,and Degree of imbalance while balancing the *** has been carried out on the Cloud Analyst platform with National Aeronautics and Space Administration(NASA)and Clarknet *** show that the proposed algorithm outperforms Ant Colony Optimization Queue Decision Maker(ACOQDM),Distributed Scheduling Optimization Algorithm(DSOA),andUtility-based Firefly Algorithm(UFA)when compared in terms of makespan,Degree of imbalance,and Figure of Merit.

关键词： Cloud computing cloudlet mobile cloud computing fuzzy firefly load balancing makespan degree of imbalance

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A Novel Approach for Mitigating Power Quality Issues in a PV Integrated Microgrid System Using an Improved Jelly Fish Algorithm

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Journal of Bionic Engineering 2023年第1期20卷 30-46页

作者： Swati suman Debashis Chatterjee Rupali Mohanty Department of Electrical Engineering Jadavpur UniversityKolkataWest Bengal700032India

A two-step methodology was used to address and improve the power quality concerns for the PV-integrated microgrid system. First, partial shading was included to deal with the real-time issues. The Improved Jelly Fish Algorithm integrated Perturb and Obserb (IJFA-PO) has been proposed to track the Global Maximum Power Point (GMPP). Second, the main unit-powered via DC–AC converter is synchronised with the grid. To cope with the wide voltage variation and harmonic mitigation, an auxiliary unit undergoes a novel series compensation technique. Out of various switching approaches, IJFA-based Selective Harmonic Elimination (SHE) in 120° conduction gives the optimal solution. Three switching angles were obtained using IJFA, whose performance was equivalent to that of nine switching angles. Thus, the system is efficient with minimised higher-order harmonics and lower switching losses. The proposed system outperformed in terms of efficiency, metaheuristics, and convergence. The Total Harmonic Distortion (THD) obtained was 1.32%, which is within the IEEE 1547 and IEC tolerable limits. The model was developed in MATLAB/Simulink 2016b and verified with an experimental prototype of grid-synchronised PV capacity of 260 W tested under various loading conditions. The present model is reliable and features a simple controller that provides more convenient and adequate performance.

关键词： Harmonic mitigation Selective harmonic elimination pulse width modulation inverters Search-based optimization techniques Bionic algorithm Total harmonic distortion Modulation indices

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On the Algebraic Functional Equation of the Eigenspaces of Mixed Signed Selmer Groups of Elliptic Curves with Good Reduction at Primes above p

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Acta Mathematica Sinica,English Series 2021年第2期37卷 289-305页

作者： suman AHMED Meng Fai LIM School of Mathematics and Statistics Central China Normal UniversityWuhan 430079P.R.China School of Mathematics and Statistics&Hubei Key Laboratory of Mathematical Sciences Central China Normal UniversityWuhan 430079P.R.China

Let p be an odd prime number,and let E be an elliptic curve defined over a number field which has good reduction at every prime above *** suitable assumptions,we prove that the η-eigenspace and the ■-eigenspace of mixed signed Selmer group of the elliptic curve are *** a corollary,we show that the η-eigenspace is trivial if and only if the ■-eigenspace is *** results can be thought as a reflection principle which relates an Iwasawa module in a given eigenspace with another Iwasawa module in a "reflected" eigenspace.

关键词： Algebraic functional equation mixed signed Selmer groups

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Two-dimensional interactions due to moving load in generalized thermoelastic solid with diffusion

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Applied Mathematics and Mechanics(English Edition) 2008年第2期29卷 207-221页

作者： Sunita Deswal suman Choudhary Department of Mathematics Guru Jambheshwar University of Science and Technology Hisar 125001HaryanaINDIA Department of Mathematics Govt.CollegeNalwa (Hisar) 125037HaryanaINDIA

The present paper is concerned with the investigation of disturbances in＇a homogeneous, isotropic elastic medium with generalized thermoelastic diffusion, when a moving source is acting along one of the co-ordinate axis on the boundary of the medium. Eigen value approach is applied to study the disturbance in Laplace-Fourier transform domain for a two dimensional problem. The analytical expressions for displacement components, stresses, temperature field, concentration and chemical potential are obtained in the physical domain by using a numerical technique for the inversion of Laplace transform based on Fourier expansion techniques. These expressions are calculated numerically for a copper like material and depicted graphically. As special cases, the results in generalized thermoelastic and elastic media are obtained. Effect of presence of diffusion is analyzed theoretically and numerically.

关键词： Eigen value approach vector matrix differential equation thermoelastic diffusion generalized thermoelasticity moving load Laplace and Fourier transforms

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Efficacy of diurnal BG-Sentinel traps to capture nocturnal adult Armigeres subalbatus mosquitoes and impact of altitudinal variations in forests

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Asian Pacific Journal of Tropical Medicine 2019年第11期12卷 512-519页

作者： Devi Shankar suman Zoological Survey of India New AliporeKolkataWest Bengal700053India

Objective:To establish an efficacious and efficient surveillance method of Armigeres(Ar.)subalbatus,a known filarial vector,surviving in forest habitats to estimate realistic population density and assess the impact of altitudinal variations on the efficacy of the ***:In the study,12 locations in areas with an altitudinal range from 82 m to 920 m were selected in three reserve forests for night sampling of adult *** mosquito using standard chemical lure based BG-Sentinel traps and CDC-light traps in *** of locations and time were estimated on the efficacy of traps as mosquito density using multifactor analysis of variance for significant *** of altitudinal variations on the efficacy of traps was assessed using multiple regression with slope ***:BG-Sentinel trap collected significantly more adult ***,4.43 folds in Gorumara NP,5.19 folds in Neora Valley NP and 12.10 folds in Mahananda WLS than the CDC-light trap irrespective to ***-Sentinel traps were tolerant of altitudinal variations(80 m-170 m)and showed no significant relationship between density and altitudes in contrast to CDC-light traps which showed a significant negative impact on capturing efficacy with increase in altitudes(P<0.001).Conclusions:The study suggests that BG-Sentinel traps can be used effectively and efficiently to collect more *** mosquitoes during night time in comparison to CDC-light trap under complex climatic conditions of forest and variable altitudes.

关键词： Mosquitoes Surveillance Adult mosquito traps Altitudinal variations Armigeres subalbatus

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New pseudo-dynamic analysis of two-layered cohesive-friction soil slope and its numerical validation

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Frontiers of Structural and Civil Engineering 2020年第6期14卷 1492-1508页

作者： suman HAZARI Sima GHOSH Richi Prasad SHARMA Department of Civil Engineering National Institute of TechnologyAgarala 799046India

Natural slopes consist of non-homlogeneous soil profiles with distinct characteristics from slopes made of homogeneous *** this study,the limit equilibrium modified pseudo-dynamic method is used to analyze the stability of two-layered c-φsoil slopes in which the failure surface is assumed to be a logarithmic *** zero-stress boundary condition at the ground surface under the seismic loading condition is *** formulations derived from an analytical method are proposed for the predicting the seismic response in two-layered soil.A detailed parametric study was performed in which various parameters(seismic accelerations,damping,cohesion,and angle of internal friction)were *** results of the present method were compared with those in the available *** present analytical analysis was also verified against the finite element analysis results.

关键词： layered soil limit equilibrium method seismic analysis damping PLAXIS

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