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Electrical transport and current properties of rare-earth dysprosium Schottky electrode on p-type GaN at various annealing temperatures

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Journal of Semiconductors 2017年第11期38卷 39-47页

作者： G.Nagaraju k.Ravindranatha reddy V.Rajagopal reddy Department of Physics Sri Venkateswara University Tirupati-517 502 India Department of Physics SGS Arts College Tirupati-517 502 India

The electrical and current transport properties of rapidly annealed Dy/p-GaN SBD are probed by I-V and C-V techniques. The estimated barrier heights（BH） of as-deposited and 200 ℃ annealed SBDs are 0.80 eV（I-V）/0.93 eV（C-V） and 0.87 eV（I-V）/1.03 eV（C-V）. However, the BH rises to 0.99 eV（I-V）/1.18 eV（C-V）and then slightly deceases to 0.92 eV（I-V）/1.03 eV（C-V） after annealing at 300 ℃ and 400 ℃. The utmost BH is attained after annealing at 300 ℃ and thus the optimum annealing for SBD is 300 ℃. By applying Cheung＇s functions, the series resistance of the SBD is estimated. The BHs estimated by I-V, Cheung＇s and ΨS-V plot are closely matched; hence the techniques used here are consistency and validity. The interface state density of the as-deposited and annealed contacts are calculated and we found that the NSS decreases up to 300 ℃ annealing and then slightly increases after annealing at 400 ℃. Analysis indicates that ohmic and space charge limited conduction mechanisms are found at low and higher voltages in forward-bias irrespective of annealing temperatures. Our experimental results demonstrate that the Poole-Frenkel emission is leading under the reverse bias of Dy/p-GaN SBD at all annealing temperatures.

关键词： p-GaN rare-earth Dy Schottky contacts annealing effects electrical properties energy distribution profiles carrier transport mechanism

Hepatitis C virus genotype 3: Meta-analysis on sustained virologic response rates with currently available treatment options

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World Journal of Gastroenterology 2016年第22期22卷 5285-5292页

作者： Javier Ampuero k Rajender reddy Manuel Romero-Gomez Inter-Centre Unit of Digestive Diseases and CIBERehd Virgen Macarena Virgen del Rocio University Hospitals University of Sevilla 41018 Sevilla Spain Instituto de Biomedicina de Sevilla 41018 Sevilla Spain Division of Gastroenterology and Hepatology Department of Medicine University of Pennsylvania Philadelphia PA 19107 United States

AIM: To address the therapeutic efficacy of various treatment regimens in genotype 3 selecting randomized clinical trials and prospective National Cohort ***:(1) PEG-INF-based therapy including sofosbuvir(SOF) + RBV for 12 wk vs SOF + RBV 24 wk;(2) SOF + RBV therapy 12 wk/16 wk vs 24 wk; and(3) the role of RBV in SOF + daclatasvir(DCV) and SOF + ledipasvir(LDV) combinations. This metaanalysis provides robust information with the intention of addressing treatment strategy for hepatitis C virus genotype ***: A combination treatment including SOF + RBV + PEG-IFN for 12 wk notes better SVR than with only SOF + RBV for 12 wk, although its association with more frequent adverse effects may be a limiting factor. Longer duration therapy with SOF + RBV(24 wk) has achieved higher SVR rates than shorter durations(12 or 16 wk). SOF + LDV are not an ideal treatment for genotype 3. CONCLUSION: Lastly, SOF + DCV combination is probably the best oral therapy option and the addition of RBV does not appear to be needed to increase SVR rates substantially.

关键词： Hepatitis C Genotype 3 Sofosbuvir Daclatasvir Ledipasvir

Substrate Temperature Dependent Properties of Cu Doped NiO Films Deposited by DC Reactive Magnetron Sputtering

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Journal of Materials Science & Technology 2013年第7期29卷 647-651页

作者： Yarraguntla Ashok kumar reddy Akepati Sivasankar reddy Pamanji Sreedhara reddy Department of Physics Sri Venkateswara UniversityTirupathi 517502India Division of Advanced Materials Engineering Kongju National UniversityBudaedongCheonan CitySouth Korea

The NiO-Cu composite films were deposited on a glass substrate at various substrate temperatures by DC reactive magnetron sputtering technique. The effect of substrate temperature on the structural, optical, morphological and electrical properties of the films was mainly investigated. X-ray diffraction studies revealed that when the substrate temperature increased to above 200 ℃, the preferred orientation tended to move to another preferred site from （220） to （111） and had a band gap values increased with increasing substrate observed that the grain size and root mean square stable cubic structure. The optical transmittance and temperature. From the morphological studies, it was roughness were increased with increasing substrate temperature. The electrical resistivity of the film decreased to 0.017 Ωcm at high substrate temperature of 400 ℃.

关键词： Sputtering NiO-Cu composite films Substrate temperature Crystallite size Electrical resistivity

Intelligent optimization of renewable resource mixes incorporating the effect of fuel risk, fuel cost and CO2 emission

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Frontiers in Energy 2015年第1期9卷 91-105页

作者： Deepak kUMAR D. k. MOHANTA M. Jaya Bharata reddy School of Electrical Sciences Indian Institute of Technology Bhuba-neswar Odisha 751013 India Electrical Engineering Department Birla Institute of Technology MesraRanchi 835215 India Electrical Engineering Department National Institute of TechnologyTrichy 620015 India

Power system planning is a capital intensive investment-decision problem. The majority of the conven- tional planning conducted since the last half a century has been based on the least cost approach, keeping in view the optimization of cost and reliability of power supply. Recently, renewable energy sources have found a niche in power system planning owing to concerns arising from fast depletion of fossil fuels, fuel price volatility as well as global climatic changes. Thus, power system planning is under-going a paradigm shift to incorporate such recent technologies. This paper assesses the impact of renewable sources using the portfolio theory to incorporate the effects of fuel price volatility as well as CO2 emissions. An optimization framework using a robust multi-objective evolutionary algorithm, namely NSGA-II, is developed to obtain Pareto optimal solutions. The performance of the proposed approach is assessed and illustrated using the Indian power system considering real-time design prac- tices. The case study for Indian power system validates the efficacy of the proposed methodology as developing countries are also increasing the investment in green energy to increase awareness about clean energy technologies.

关键词： modem portfolio theory energy policy CO2 emissions multi-objective optimization planning commis-sion

Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

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Defence Technology（防务技术） 2017年第2期13卷 59-71页

作者： Raffi Mohammed G.Madhusudhan reddy k.Srinivasa Rao Department of Metallurgical Engineering Andhra University Visakhapatnam India Defence Metallurgical Research Laboratory Hyderabad India

High nitrogen stainless steel(HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion *** fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical *** above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding(SMAW), gas tungsten arc welding(GTAW), electron beam welding(EBW) and friction stir welding(FSW) processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam *** recrystallized austenite grain structure was observed in the nugget zone of friction stir *** mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains.

关键词： High nitrogen austenitic stainless steel(HNS) Shielded metal arc welding (SMAW) Gas tungsten arc welding (GTAW) Electron beam welding (EBW) Friction stir welding (FSW)

Interactive effects of carbon dioxide, low temperature, and ultrav｜olet-B radiation on cotton seedling root and shoot morphology and growth

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Frontiers of Earth Science 2016年第4期10卷 607-620页

作者： David BRAND Chathurika WIJEWARDANA Wei GAO k. Raja reddy Department of Plant and Soil Sciences Mississippi State University Starkwille MS 39762 USA USDA UVB Monitoring and Research Program Natural Resource Ecology Laboratory and Department of Ecosystem Science and Sustainability Colorado State University Fort Collins CO 80523 USA

Interactive effects of multiple environmental stresses are predicted to have a negative effect on cotton growth and development and these effects will be exacerbated in the future climate. The objectives of this study were to test the hypothesis that cotton cultivars differ in their responses to multiple environmental factors of （CO2） [400 and 750 μ*** 1 （＋（CO2）], temperature [28/20 and 20/12℃ （-T）], and UV-B radiation [0 and 10 kJ. m2. d ^-1（＋ UV- B）]. A genetic and molecular standard （TM-1） and three modern cotton cultivars （DP1522B2XE PHY496W3R, and ST4747GLB2） were grown in eight sunlit, controlled environment chambers with control treatment 400 μ***^-1 [CO2], 28/21℃ temperature, and 0 kJ UV B. The results showed significant differences among the cultivars for most of the shoot and root parameters. Plants grown under low temperature alone or as a combination with ＋ UV B treatment caused more detrimental effects on root and shoot vigor. Although the elevated CO2 treatments weakened the damaging effects of higher UV-B levels on cotton growth on all cultivars, increased CO2 could not mask the negative effects of low temperature. When comparing all cultivars, genetic standard TM-1 produced the smallest values for the majority of traits under CO2, UV-B, and low temperature either alone or in combination with other treatments. Based on principal component analysis, the four cultivars were classified as tolerant （DP1522B2XF）, intermediate （PHY496W3R and ST4747GLB2） and sensitive （TM-1） to multiple environmental *** temperature was identified as the most damaging treatment to cotton early seedling vigor while elevated CO2 caused the least. Existing variability of cotton cultivars in response tomultiple environmental stresses could allow for selection of cultivars with the best coping ability and higher lint yield for future climate change environments.

关键词： Cotton Climate change winRHIZO Princi-pal component analysis. Stress tolerance.

A comparative analysis of unsteady and steady Buongiorno’s Williamson nanoliquid flow over a wedge with slip effects

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Chinese Journal of Chemical Engineering 2020年第7期28卷 1767-1777页

作者： R.Chandra Sekhar reddy P.Sudarsana reddy Department of Mathematics Rajeev Gandhi Memorial Collge of Engineering&TechnologyNandyalA.P.India

Comparison between unsteady and steady MHD Buongiorno’s model Williamson nanoliquid flow through a wedge with slip effects,chemical reaction and radiation is made in this *** and Brownian motion are also considered in this *** similarity variables are presented to transmute the governing PDEs into the set of non-linear *** most widely authenticated finite element method is implemented to analyze these set of ODEs *** behavior of concentration,temperature and velocity sketches for varied values of relevant parameters is numerically calculated and the outcomes are plotted through *** numerical values of dimensionless rates of mass transfer,heat and velocity are also evaluated and depicted through *** is noted that with upsurging values of angle of wedge parameter,the distributions of temperature of the liquid intensify in both steady and unsteady cases.

关键词： Finite element method Chemical reaction Williamson nanoliquid Thermophoresis Thermal radiation Brownian motion

Non-classical continuum theories for solid and fluent continua and some applications

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International Journal of Smart and Nano Materials 2019年第1期10卷 28-89,I0003页

作者： k.S.Surana D.Mysore J.N.reddy Mechanical Engineering University of KansasLawrenceKSUSA Mechanical Engineering Texas A&M UniversityCollege StationTXUSA

This paper presents two specific thermodynamically consistent nonclassical continuum theories for solid and fluent *** first non-classical continuum theory for solid continua incorporates Jacobian of deformation in its entirety in the conservation and the balance laws and the derivation of the constitutive *** second non-classical continuum theory for solid continua considers Jacobian of deformation in its entirety as well as the Cosserat rotations in the conservation and balance laws as well as the constitutive *** first non-classical continuum theory for fluent continua presented here considers velocity gradient tensor in its *** second non-classical continuum theory for fluent continua considers velocity gradient tensor in its entirety as well as Cosserat rotation rates in the derivation of the conservation and balance laws and the constitutive *** the non-classical continuum theories for solid and fluent continua considered here incorporate additional physics of deformation due to rotations and rotation rates compared to classical continuum mechanics,the conservation and balance laws of classical continuum mechanics are shown to require modification as well as a new balance law balance of moment of moments is required to accommodate the new physics due to rotations and rotation ***’s micropolar,micromorphic and microstretch theories,couple stress theories and nonlocal theories are also discussed within the context of the non-classical theories presented here for solid and fluent *** applications of these theories are also discussed.

关键词： Non-classical continuum theories micropolar Jacobian of deformation internal rotations Cosserat rotations Cosserat rotation rates

Ballistic behavior of boron carbide reinforced AA7075 aluminium alloy using friction stir processing-An experimental study and analytical approach

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Defence Technology（防务技术） 2016年第1期12卷 25-31页

作者： I.SUDHAkAR G.MADHUSUDHAN reddy k.SRINIVASA RAO department of mechanical engineering mvgrceVizianagaramIndia defence metallurgical research laboratory HyderabadIndia department of metallurgical engineering andhra universityVisakhapatnamIndia

High strength-to-weight ratio of non-ferrous alloys, such as aluminium, magnesium and titanium alloys, are considered to be possible replacement of widely accepted steels in transportation and automobile sectors. Among these alloys, magnesium is self explosive and titanium is costlier, and aluminium is most likely to replace steels. Application of aluminium or its alloys is also thought of as an appropriate replacement in defence field, especially to enhance the easiness in mobility of combat vehicles while maintaining the same standard as that of conventional armour grade steels. Hence most of the investigations have been confined to aluminium or its alloys as base material and open an era of developing the newer composite materials to address the major limitation, i.e. tribological properties. The surface composites can be fabricated by incorporating the ceramic carbides like silicon carbide, carbides of transition metals and oxides of aluminium using surface modification techniques, such as high energy laser melt treatment, high energy electron beam irradiation and thermal spray process which are based on fusion route. These techniques yield the fusion related problems, such as interfacial reaction, pin holes, shrinkage cavities or voids and other casting related defects, and pave the way to need of an efficient technique which must be based on solid state. Recently developed friction stir processing technique was used in the present investigation for surface modification of AA7075 aluminum alloy, which is an alternative to steels. In the present investigation, 160 μm sized boron carbide powder was procured and was reduced to 60 μm and 30 μm using high energy ball mill. Subsequently these powders were used to fabricate the surface composites using friction stir *** performance testing as per the military standard(JIS.0108.01) was carried out. In the present work, an analytical method of predicting the ballistic behavior of surface composites was

关键词： AA7075 aluminium alloy Friction stir processing(FSP) Surface metal matrix composite(SMMC) Boron carbide(B4C) Ballistic performance Target