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Broadband ferromagnetic resonance studies on influence of interface bonding on magnetoeletric effects in ferrit e-ferroelectric composites

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Frontiers of physics 2012年第4期7卷 418-423页

作者： D.v.B.murthy Gopalan Srinivasan Physics Department Oakland UniversityRochesterMI 48309USA

A systematic study has been carried out on the effects of interface bonding on the strain mediated magnetoelectric （ME） coupling in ferromagnetic-ferroelectric bilayers. The technique used involves the static electric field E tuning of the ferromagnetic resonance （FMr） in yttrium iron garnet （YIG） and lead zirconate titanate （PZT） or lead magnesium niobate-lead titanate （PMN-PT）. A broad band detection technique has been developed for studies over 1 40 GHz in three types of bilayers： epoxy bonded, eutectic bonded and YIG films directly grown onto piezoelectric substrate by electrophoretic deposition. The strength A of the converse ME effect （CME） defined as the ratio of the frequency shift 8f in FMr in E, A = 8f/E, varies over the range 0.8 to 4.3 ***/kv, and is the highest for eutectic bonded samples and is the weakest for epoxy bonded bilayers. The results presented here as of importance for dual electric and magnetic field tunable ferrite ferroelectric microwave resonators and filters.

关键词： Keywords ferrite ferroelectric magnetoelectric ferromagnetic resonance

Unveiling urbanization effects on trees outside forests along the urban-rural gradient in megacity Bengaluru

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Forest Ecosystems 2025年第01期 56-65页

作者： Tao Jiang Maximilian Freudenberg Christoph Kleinn v.P.Tewari B.N.Diwakara Nils N?lke Forest Inventory and remote Sensing Department Faculty of Forest Sciences and Forest Ecology University of G?ttingen Himalayan Forest research Institute ICFRE Institute of Wood Science and Technology IWST

rapid urbanization has caused significant changes along the urban-rural gradient, leading to a variety of landscapes that are mainly shaped by human activities. This dynamic interplay also influences the distribution and characteristics of trees outside forests(TOF). Understanding the pattern of these trees will support informed decision-making in urban planning, in conservation strategies, and altogether in sustainable land management practices in the urban context. In this study, we employed a deep learning-based object detection model and high resolution satellite imagery to identify 1.3 million trees with bounding boxes within a 250 km2research transect spanning the urban-rural gradient of Bengaluru, a megacity in Southern India. Additionally, we developed an allometric equation to estimate diameter at breast height(DBH) from the tree crown diameter(CD) derived from the detected bounding boxes. Our study focused on analyzing variations in tree density and tree size along this gradient. The findings revealed distinct patterns: the urban domain displayed larger tree crown diameters(mean:8.87 m) and DBH(mean: 43.78 cm) but having relatively low tree density(32 trees per hectare). Furthermore,with increasing distance from the city center, tree density increased, while the mean tree crown diameter and mean tree basal area decreased, showing clear differences of tree density and size between the urban and rural domains in Bengaluru. This study offers an efficient methodology that helps generating instructive insights into the dynamics of TOF along the urban-rural gradient. This may inform urban planning and management strategies for enhancing green infrastructure and biodiversity conservation in rapidly urbanizing cities like Bengaluru.

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Chemoselective Dehydrogenation of 3-[2-(3,4-Dihydro-1-naphthalenyl)ethyl]imidazolidine-2,4-diones: a New and Convenient Synthesis of 13,16-Diazaequilenin analogs

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Chinese Journal of Chemistry 2004年第10期22卷 1196-1199页

作者： PArIHAr J.A ramana M.M.v Department of Chemistry University of Mumbai Santacruz (E) Mumbai-400098 IndiaDepartment of Chemistry University of Mumbai Santacruz (E) Mumbai-400098 India

The synthesis of the title compounds starting with the chemoselective dehydrogenation of 3-[2-(3,4-dihydro-1-naphthalenyl)ethyl]imidazolidine-2,4-diones has been described.

关键词： chemoselective dehydrogenation imide reduction intramolecular cyclization 13,16-diazasteroid

FINITE DIFFErENCE METHODS FOr THE HEAT EQUATION WITH A NONLOCAL BOUNDArY CONDITION

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Journal of Computational Mathematics 2015年第1期33卷 17-32页

作者： v. Thomee A.S. vasudeva murthy Mathematical Sciences Chalmers University of Technology and University of Gothenburg SE-412 96 GSteborg Sweden TIFr Centre for Appl. Math Yelahanka New Town Bangalore India

We consider the numerical solution by finite difference methods of the heat equation in one space dimension, with a nonlocal integral boundary condition, resulting from the truncation to a finite interval of the problem on a semi-infinite interval. We first analyze the forward Euler method, and then the 0-method for 0 〈 θ ≤ 1, in both cases in maximum-norm, showing O（h2 ＋ k） error bounds, where h is the mesh-width and k the time step. We then give an alternative analysis for the case θ= 1/2, the Crank-Nicolson method, using energy arguments, yielding a O（h2 ＋ k3/2） error bound. Special attention is given the approximation of the boundary integral operator. Our results are illustrated by numerical examples.

关键词： Heat equation Artificial boundary conditions unbounded domains productquadrature.

Mathematical modelling of couple stresses on fluid flow in constricted tapered artery in presence of slip velocity-effects of catheter

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Applied Mathematics and Mechanics(English Edition) 2014年第8期35卷 947-958页

作者： J.v.r.rEDDY D.SrIKANTH S.K.murthy Department of Applied Mathematics Defence Institute of Advanced Technology Deemed UniversityPune 411025MaharastraIndia

This paper explores the mathematical model for couple stress fluid flow through an annular region. The above model is used for studying the blood flow be-tween the clogged （stenotic） artery and the catheter. The asymmetric nature of the stenosis is considered. The closed form expressions for the physiological parameters such as impedance and shear stress at the wall are obtained. The effects of various geomet-ric parameters and the parameters arising out of the fluid considered are discussed by considering the slip velocity and tapering angle. The study of the above model is very significant as it has direct applications in the treatment of cardiovascular diseases.

关键词： blood flow couple stress fluid stenosed artery tapered artery catheter

Optimization of luminescence properties of Tb^(3+)-doped a-Sr_2P_2O_7 phosphor synthesized by combustion method

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rare Metals 2018年第7期37卷 587-593页

作者： Nimesh Prafulbhai Patel Mangalampalli Srinivas Dhaval Modi vishwnath verma Kota venkata ramana murthy Luminescence Material Laboratory Department of PhysicsFaculty of Science The M. S. University of Baroda Vadodara 390002 India Display Materials Laboratory Applied Physics DepartmentFaculty of Technology and Engineering The M. S. University of Baroda Vadodara 390001 India

In this paper, thermoluminescence （TL） properties of rare earth Tb^3＋-doped α-Sr2P2O7 were examined after β-irradiation and photoluminescence （PL） properties of samples were examined for proper excitation. All the samples were synthesized by high-temperature combustion method. The X-ray diffraction （XrD） and Fourier transform infrared （FTIr） spectroscopy characterization confirms the formation of pure α-phase with crystallized in orthorhombic structure of samples. The PL emission spectra of all samples exhibit characteristic green emission peaks of Tb^3＋ where the peak at 545 nm has the highest emission intensity for Tb^3＋ con- centration of 5.0 mol%. The TL glow curves of β-irradiated Tb^3＋-doped α-Sr2P2O7 phosphors were recorded at different heating rates of 2, 4, and 6 K.s^-1. TL curves of all sample exhibit combination of two peaks： peak at 420 K shifts toward higher 525 K remains unaffected temperature, while peak at with the increase in Tb^3＋ concentration as well as fading effect. The activation energy and kinetic parameters of the samples were evaluated using thermoluminescence peak shape method.

关键词： rare earth doping Strontium pyrophosphate β-Irradiation Photoluminescence Thermoluminescence

Static and cyclic oxidation of Nb-Cr-v-W-Ta high entropy alloy in air from 600 to 1400℃

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Journal of Materials Science & Technology 2020年第3期38卷 189-196页

作者： S.K.varma Francelia Sanchez Sabastian Moncayo C.v.ramana Department Metallurgical Materials and Biomaterials EngineeringThe University of Texas at El PasoEl PasoTX79968-0520USA Center for Advanced Materials research(CMr) The University of Texas at El PasoEl PasoTX79968-0520USA

An oxidation resistance study has been made on Nb-Cr-v-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in *** oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation *** oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating *** alloy can withstand the cyclic oxidation process with only a reasonable loss of *** identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and Cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of v in whisker forms at 1200℃.

关键词： High entropy alloys Nb-Cr-v-W-Ta Microstructures Oxidation

Modelling reference evapotranspiration using gene expression programming and artificial neural network at Pantnagar,India

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Information Processing in Agriculture 2023年第4期10卷 547-563页

作者： Pangam Heramb Pramod Kumar Singh K.v.ramana rao A.Subeesh Division of Irrigation and Drainage Engineering ICAR-Central Institute of Agricultural EngineeringBhopal 462038India Department of Irrigation and Drainage Engineering G.B.Pant University of Agriculture and TechnologyPantnagar 263145India Division of Agricultural Mechanization ICAR-Central Institute of Agricultural EngineeringBhopal 462038India

Evapotranspiration is an essential component of the hydrological cycle that is of particular interest for water resource *** quantification is helpful in irrigation scheduling,water balance studies,water allocation,*** of reference evapotranspiration(ET0)using both gene expression programming(GEP)and artificial neural network(ANN)techniques was done using the daily meteorological data of the Pantnagar region,India,from 2010 to 2019.A total of 15 combinations of inputs were used in developing the ET0 *** model with the least number of inputs consisted of maximum and minimum air temperatures,whereas the model with the highest number of inputs consisted of maximum air temperature,minimum air temperature,mean relative humidity,number of sunshine hours,wind speed at 2mheight and extra-terrestrial radiation as inputs and with ET0 as the output for all the *** the GEP models were developed for a single functional set and pre-defined genetic operator values,while the best structure in each ANN model was found based on the performance during the testing *** was found that ANN models were superior to GEP models for the estimation *** was evident from the reduction in rMSE values ranging from 2%to 56%during training and testing phases in all the ANN models compared with GEP *** ANN models showed an increase of about 0.96%to 9.72%of r2 value compared to the respective GEP *** comparative study of these models with multiple linear regression(MLr)depicted that the ANN and GEP models were superior to MLr models.

关键词： Artificial Neural Networks Evolutionary algorithms Gene Expression Programming Machine Learning regression Analysis reference evapotranspiration models

3D打印连续纤维增强树脂基复合材料的研究进展

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材料工程 2025年第2期53卷 50-70页

作者：张明孙中刚郭艳华戴国庆 ALEXANDrOv v.I. 南京工业大学材料科学与工程学院新材料研究院南京210009 乌法科技大学金属材料科学与物理系俄罗斯乌法450008

连续纤维增强树脂基复合材料因其密度低、力学性能优异被广泛应用于航空航天、汽车和船舶等工业领域,传统制造工艺因模具限制成本高昂且无法成型复杂零部件。增材制造设计自由度高、快速灵活等优点被认为是连续纤维增强复合材料未来生... 详细信息

连续纤维增强树脂基复合材料因其密度低、力学性能优异被广泛应用于航空航天、汽车和船舶等工业领域,传统制造工艺因模具限制成本高昂且无法成型复杂零部件。增材制造设计自由度高、快速灵活等优点被认为是连续纤维增强复合材料未来生产的重要方向之一。目前连续纤维增强复合材料的增材制造技术发展仍处于起步阶段,本文系统综述了连续纤维增强树脂基复合材料的研究现状,概述了打印的装备、工艺、材料的研究进展,为连续纤维增强树脂基复合材料的打印平台搭建以及工程化应用提供了方向,重点分析了打印温度、打印速度和打印层厚等工艺参数对打印质量的影响,为连续纤维增强复合材料的智能增材制造提供参考,同时讨论了连续纤维的二维和三维的结构设计在轻量化制造方面的发展,如纤维路径铺设和结构拓扑优化,并对连续纤维增强复合材料增材制造的设备、材料、打印工艺和结构设计的研究发展趋势进行了总结和展望。

关键词：连续纤维树脂基增材制造工艺参数结构设计

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