检索结果-南通市图书馆

Radiation Losses in the Microwave X Band in Al-Cr Substituted Y-Type Hexaferrites

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2017年第4期34卷 35-38页

作者： D.Basandrai R.K.Bedi A.Dhami j.sharma S.B.Narang K.Pubby A.K.Srivastava Research Scholar Department of Physics I. K. Gujral Punjab Technical University Jalandhar India Department of Physics Lovely Professional University Phagwara India principal Satyam Institute of Engineering & Technology Amritsar India Department of Electronic Technology Guru Nanak Dev University Amritsar India

We present a study on radiation losses in the microwave X band in Al-Cr substituted Y-type hexaferrites, namely Ba2Mg2Alx/2Crx/2Fe12-xO22 （x = 0, 0.5 and 1.0）. The study is performed by means of a vector network analyzer, Fourier transform infrared spectroscopy, a vibrating sample magnetometer and x-ray powder diffraction. Ba2Mg2Fe12O22 hexaferrite shows radiation loss of -37.25dB （99.999% loss） at frequency 9.81 GHz, which can be attributed to its high value of saturation magnetization, i.e., 22.08emu/g. Moreover, we obtain that magnetic properties have strong influence on the radiation losses.

关键词： Ba Al Radiation Losses in the Microwave X Band in Al-Cr Substituted Y-Type Hexaferrites Cr

Mathematical Modelling and Analysis of Lamb Waves in Elasto-Thermodiffusive Plates

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2010年第2期2卷 238-258页

作者： j.N.sharma P.K.sharma Department of Applied Sciences National Institute of TechnologyHamirpur 177005India Department of Mathematics SL Bawa Dayanand Anglo Vedic CollegeBatala 143505India

The propagation characteristics of elasto-thermodiffusive Lamb waves in a homogenous isotropic,thermodiffusive,elastic plate have been investigated in the context of linear theory of generalized *** developing the formal solution of the mathematical model consisting of partial differential equations,the secular equations have been derived by using relevant boundary conditions prevailing at the surfaces of the plate for symmetric and asymmetric wave modes in completely separate *** secular equations for long wavelength and short wavelength waves have also been deduced and *** amplitudes of displacement components,temperature change and mass concentration under the Lamb wave propagation conditions have also been *** complex transcendental secular equations have been solved by using a hybrid numerical technique consisting of irreducible Cardano method along with function iteration technique after splitting these in a system of real transcendental *** numerically simulated results in respect of phase velocity,attenuation coefficient,specific loss factor and relative frequency shift of thermoelastic diffusive waves have been presented graphically in the case of brass material.

关键词： Diffusion Cardano method relative frequency thermal relaxation iteration method

Assessment of Man-made and Natural Hazards in the Surroundings of Hydropower Projects under Construction in the Beas Valley of Northwestern Himalaya

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Mountain Science 2007年第3期4卷 221-236页

作者： Sanjeev sharma jagdish C. Kuniyal j. C. sharma G.B. Pant Institute of Himalayan Environment & Development Himachal UnitMohal-Kullu 175 126Himachal Pradesh India Department of Geography Himachal Pradesh University

Mountain ecosystem, on the earth, has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade However, every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya, it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards, such as landslides, rock fall and soil erosion, have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study, therefore, focuses mainly on the Parbati Stage II （800 MW） and the Parbati Stage III （520 MW） hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities, the existing land use pattern, status of total acquired land of the residents by hydropower projects, frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage II and III have been analysed in the paper. Also, the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.

关键词： Hydropower project under construction local community hazard preventive measure environment northwestern Indian Himalaya

TransientWaves Due to Mechanical Loads in Elasto-Thermo-Diffusive Solids

在线全文

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2011年第1期3卷 87-108页

作者： j.N.sharma N.K.sharma K.K.sharma Department of Applied Sciences and Humanities National Institute of TechnologyHamirpur-177005India

This paper deals with the study of transient waves in a homogeneous isotropic,solid halfspace with a permeating substance in the context of the theory of generalized *** halfspace is assumed to be disturbed due to mechanical loads acting on its *** model comprising of basic governing differential equations and boundary conditions has been solved by employing Laplace transform *** that the second sound effects are short lived,the small time approximations of solution for various physical quantities have been obtained and the results are discussed on the possible wave *** case of continuous and periodic loads acting at the boundary,the displacement is found to be continuous at each wave front while it is discontinuous in case of impulsive *** temperature and concentration fields are found to be discontinuous at all the wave *** displacement,temperature change and concentration deviation due to impulsive,continuous and periodic mechanical loads have also been evaluated in the physical domain at all times by employing numerical inversion technique of integral *** computer simulated numerical results have been presented graphically in respect of displacement,temperature change and concentration deviation for brass.A significant effect of mass diffusion has been observed on the behaviour of mechanical and thermal waves.

关键词： Diffusion Laplace transform small time approximations wave fronts

Vibration analysis of axisymmetric functionally graded viscothermoelastic spheres

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第1期30卷 100-111页

作者： D.K.sharma j.N.sharma S.S.Dhaliwal V.Walia Department of Mathematics Sant Longowal Institute of Engineering and Technology Department of Mathematics National Institute of Technology

The present study focuses on the analysis of free vibrations of axisymmetric functionally graded hollow spheres. The material is assumed to be graded in radial di- rection with a simple power law. Matrix Frrbenious method of extended power series is employed to derive the analytical solutions for displacement, temperature, and stresses. The dispersion relations for the existence of various types of pos- sible modes of vibrations in the considered hollow sphere are derived in a compact form. In order to explore the character- istics of vibrations, the secular equations are further solved by using fixed point iteration numerical technique with the help of MATLAB software. The numerical results have been presented graphically for polymethyl methecrylate materials in respect of natural frequencies, frequency shift, inverse quality factor, displacement, temperature change, and radial stress.

关键词： Functionally graded Stresses Vibrations Fr6benius - Dispersion - Spherical structures

Manifestation of earthquake preparation zone in the ionosphere before 2021 Sonitpur,Assam earthquake revealed by GPS-TEC data

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2022年第3期13卷 230-237页

作者： Gopal sharma North Eastern Space Applications Centre Umiam793103MeghalayaIndia

Global Positioning System(GPS)Continuously Operating Reference Station(CORS)data analysis shows that the ionosphere’s electron density variability is linked to the deformation and stress accumulation in the Earth’s *** in ionosphere total electron content(TEC)variability before 2021 M6.4 Sonitpur,Assam earthquake were detected using L1 and L2 GPS frequencies that showed three distinct abnormalities on April 3,9,10,***’s correlation coefficient(r)of TEC decreases in the CORS that lies away from the earthquake epicenter,indicating the possibilities of a positive relationship between TEC variability and earthquake *** concentration also decreases towards the epicenter within the earthquake preparation zone(EPZ).It is also observed that the Pearson’s correlation coefficient(r)of TEC decreases linearly near the *** study demonstrates the possibilities of determining the TEC anomalous zone in the ionosphere that coincides with the EPZ in the crustal *** research indicated the possibilities of magnitude estimation of an impending earthquake based on the TEC anomalous zone in the ionosphere using closely spaced dense CORS network data.

关键词： GPS TEC Sonitpur earthquake Ionosphere perturbation TEC anomaly Magnitude estimation

Nuclear structure study of some bubble nuclei in the light mass region using mean field formalism

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2015年第6期39卷 47-53页

作者： Mahesh K.sharma R.N.Panda Mano j K.sharma S.K.Patra School of Physics and Material Sciences Thapar University

We study the structural properties of some light mass nuclei using two different formalisms(i) a recently developed simple effective interaction in the frame work of microscopic non-relativistic Hartree-Fock method and(ii)the well-known relativistic mean field approach with NL3 parameter set. The bulk properties like binding energy, root mean square radii and quadrupole deformation parameter are estimated and compared with the available experimental data. The predicted results of both the formalisms are well comparable with the experimental observations. The analysis of density profiles of these light mass nuclei suggest that22 O,23F,34 Si and46Ar have bubble like structure.

关键词： binding energy charge radius relativistic mean field simple effective interaction non-relativistic mean fields

Numerical simulation of square shaped particle sedimentation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第1期84卷 107-116页

作者： Govind sharma Bahni Ray Department of Mechanical Engineering Indian Institute of Technology DelhiHauz KhasNew Delhi110016India

Direct numerical simulations of square particle sedimentation in a viscous incompressible fluid are presented to examine the effects of sharp edges for various particle-to-fluid density ratios and different initial inclination *** settling process exhibits four different motion regimes;non-oscillatory,non-uniform centered oscillatory,uniform off-centered oscillatory,and non-uniform off-centered(irregular)*** moderate density ratios,we observe that the rotational motion of settling square particle varies with the initial inclination *** employ Dynamic Time Warping and Fast Fourier Transform to analyze translational and angular *** systems are described using phase-space plots,and a chaotic phenomenon is observed at a higher density ratio.

关键词： Sedimentation Distributed Lagrangian multiplier Phase synchronization Oscillations

Perfusability and immunogenicity of implantable pre-vascularized tissues recapitulating features of native capillary network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bioactive Materials 2023年第12期30卷 184-199页

作者： Dhavan sharma Archita sharma Linghao Hu Te-An Chen Sarah Voon Kayla j.Bayless jeremy Goldman Alex j.Walsh Feng Zhao Department of Biomedical Engineering Texas A&M UniversityCollege StationTXUnited States School of Medicine Texas A&M UniversityCollege StationTXUnited States Department of Biomedical Engineering Michigan Technological UniversityHoughtonMIUnited States

Vascularization is a key pre-requisite to engineered anatomical scale three dimensional(3-D)constructs to ensure their nutrient and oxygen supply upon ***,engineered pre-vascularized 3-D tissues are limited to only micro-scale hydrogels,which meet neither the anatomical scale needs nor the complexity of natural extracellular matrix(ECM)*** scale perfusable constructs are critically needed for translational *** overcome this challenge,we previously developed pre-vascularized ECM sheets with long and oriented dense microvascular *** present study further evaluated the patency,perfusability and innate immune response toward these pre-vascularized ***-co-cultured prevascularized constructs were evaluated in vitro to confirm micro-vessel patency and perturbations in macrophage *** implanted pre-vascularized constructs remained viable and formed a functional anastomosis with host vasculature within 3 days of *** completely biological pre-vascularized construct holds great potential as a building block to engineer perfusable anatomical scale tissues.

关键词： Pre-vascularization Micro-vasculature Mesenchymal stem cells Extracellular matrix Fluorescence lifetime imaging