检索结果-南通市图书馆

Structural and Dielectric Properties of Sn Doped Barium Magnesuim Zirconium Titanate Perovskite Ceramics

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

World Journal of Condensed Matter Physics 2015年第4期5卷 346-352页

作者： Sankararao gattu Kamala Sujani Dasari Venkata ramesh Kocharlakota Department of Physics MVJ College of Engineering Near ITPB Bangalore India Department of Physics A. C. College Guntur India Deptartment of Physics GITAM Institute of Science GITAM University Visakhapatnam India

Perovskite type ceramics (Ba0.9Mg0.1)(SnxZr0.4-xTi0.6)O3 (with x = 0.01, 0.02, 0.03 and 0.04) relaxor composition prepared through solid state reaction route and calcinated at temperature is 1150°C for 5 hrs with intermediate mixing. The room temperature XRD study suggests that all the samples have the single phase cubic symmetry with space group pm 3 m. The pellets were sintered at 1500°C for 4 hrs. Scanning Electron Microscope (SEM) observations revealed enhanced micro structural uniformity and retarded grain growth with decreasing Sn content. The dielectric measurements at constant frequency show that dielectric constant increases with Sn content. Loss factor and dielectric constant decreased with increasing frequency but at very high frequencies it was independent.

关键词： Sn Doped Barium Titanate Dielectric Properties Perovskite Lead Free Ceramics

Effect of Zr on Structural and Dielectrical Properties of (Ba0.9Mg1.0)(ZrxTi1-x)O3Ceramics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Materials Physics and Chemistry 2015年第10期5卷 419-425页

作者： Sankararao gattu Venuturupalli Durga Prasadu Kocharlakota Venkata ramesh Department of Physics MVJ College of Engineering Bangalore India Department of Physics GITAM Institute of Technology GITAM University Visakhapatnam India

Barium titanate, BaTiO3 (BTO) is the most common ferro electric material, which is used to manufacture electronic components such as multilayer capacitors, positive temperature coefficient thermistors, piezo electric transdures, and ferro electric memory. Zr doped barium magnesium titanate (Ba0.9Mg1.0)(ZrxTi1-x)O3 (with x = 0.10, 0.20, 0.40 (BMZT 10, BMZT 20 and BMZT 40) perovskite is prepared by conventional solid state reaction method. The starting raw materials were BaCO3, TiO2, MgO and ZrO2. The XRD study at room temperature suggests that these have cubic and tetragonal symmetry phases. The behavior of the measured dielectric permittivity and dielectric loss with temperature and frequency reveals that the materials undergo a diffuse para-ferroelectric phase transition and are of the relaxor type. The crystal structure, surface morphology and dielectric properties of Zr and Mg doped barium titanate ceramics were investigated. Zr4+ and Mg2+ ions have entered the unit cell maintaining the perovskite structure of solid solution without the evidence of any additional phase when Mg content is 0.1 mole% and the Zr content is 0.10, 0.20 and 0.40 mole%.

关键词： Lead Free Ceramics BaTiO3 Dielectric Materials Impedance XRD SEM

Water-soluble-template-derived nanoscale silicon nano- flake and nano-rod morphologies： Stable architectures for lithium-ion battery anodes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2017年第12期10卷 4284-4297页

作者： Bharat gattu Prashanth Hanumantha Jampani Moni Kanchan Datta Ramalinga Kuruba Prashant N. Kumta Department of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh PA 1526 I USA Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh PA 15261 USA Department of Bioengineering University of Pittsburgh Pittsburgh PA 1526 I USA Center for Complex Engineered Multifunctional Materials (CCEMM) University of Pittsburgh PA 15261 USA

Earth abundant and economical rock salt （NaC1） particles of different sizes （〈3 μm and 5-20 μm） prepared by high energy mechanical milling were used as water-soluble templates for generation of Si with novel nanoscale architectures via low pressure chemical vapor deposition （LPCVD）. Si nanoflakes （SiNF） comprising largely amorphous Si （a-Si） with a small volume fraction of nanocrystalline Si （nc-Si）, and Si nanorods （SiNR） composed of a larger volume fraction of crystalline Si （c-Si） and a small volume fraction of a-Si resulted from modification of the NaCI crystals. SiNF yielded first-cycle discharge and charge capacities of -2,830 and 2,175 mAh.g-1, respective134 at a current rate of 50 mA.g-1 with a first-cycle irreversible loss （FIR loss） of -15%-20%. SiNR displayed first-cycle discharge and charge capacities of -2,980 and -2,500 mAh-g-1, respectively, at a current rate of 50 mA-g-1 with an FIR loss of -12%-15%. However, at a current rate of 1 A.g-1, SiNF exhibited a stable discharge capacity of -810 mAh-g-1 at the end of 250 cycles with a fade rate of -0.11% loss per cycle, while SiNR showed a stable specific discharge capacity of -740 mAh.g-1 with a fade rate of -0.23% loss per cycle. The morphology of the nanostructures and compositions of the different phases/phase of Si influence the performance of SiNF and SINK, making them attractive anodes for lithium-ion batteries.

关键词： silicon nanoflakes nanorods water-soluble template NaC1

A rapid solid-state synthesis of electrochemically active Chevrel phases （Mo6T8; T = S, Se） for rechargeable magnesium batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2017年第12期10卷 4415-4435页

作者： Partha Saha Prashanth H. Jampani Moni K. Datta Daeho Hong Bharat gattu Prasad Patel Karan S. Kadakia Ayyakkannu Manivannan Prashant N. Kumta Department of Bioengineering Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA U.S. Department of Energy National Energy Technology Laboratory Morgantown WV26507 USA Mechanical Engineering and Materials Science Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA Chemical and Petroleum Engineering Swanson School of Engineering University of Pittsburgh Pittsburgh PA 15261 USA School of Dental Medicine University of Pittsburgh Pittsburgh PA 15251 USA Center for Complex Engineered Multifunctional Materials University of Pittsburgh Pittsburgh PA 15261 USA Present address: Department of Ceramic Engineering Nationallnstitute ofTechnology-Rourkela Odisha-769008 India

High energy mechanical milling （HEMM） of a stoichiometric mixture of molybdenum and metal chalcogenides （CuT and MOT2; T = S, Se） followed by heat treatment at elevated temperatures was successfully applied to synthesize Chevrel phases （Cu2Mo6T8; T = S, Se） as positive electrodes for rechargeable magnesium batteries. Differential scanning calorimetry （DSC）, thermogravimetric analyses （TGA）, X-ray diffraction （XRD）, and scanning electron microscopy （SEM） were used to understand the phase formation following milling and heat treatment. CuS and Mo were observed to react at 714-800 K and formed an intermediate ternary Chevrel phase （Cu1.83Mo3S4）, which further reacted with residual Mo and MoS2 to form the desired Cu2MosSs. Quantitative XRD analysis shows the formation of a -96%-98% Chevrel phase at 30 min following the milling and heat treatment. The electrochemical performance of de-cuprated Mo6S8 and Mo6Ses phases were evaluated by cyclic voltammetry （CV）, galvanostatic cycling, and electrochemical impedance spectroscopy （EIS）. The results of the CV and galvanostatic cycling data showed the expected anodic/cathodic behavior and a stable capacity after the first cycle with the formation of MgxMo6T8 （T = S, Se; 1 ≤ x 〈 2）. EIS at -0.1 V intervals for the Mo6Ss electrode during the first and second cycle shows that partial Mg-ion trapping resulted in an increase in charge transfer resistance Re. In contrast, the interfacial resistance Ri remained constant, and no significant trapping was evident during the galvanostatic cycling of the Mo6,Se8 electrode. Importantly, the ease of preparation, stable capacity, high Coulombic efficient35 and excellent rate capabilities render HEMM a viable route to laboratory-scale production of Chevrel phases for use as positive electrodes for rechargeable magnesium batteries.

关键词： magnesium battery Chevrel phase high energy mechanicalmilling electrochemical properties

Marker-Assisted Pyramiding of Genes Conferring ResistanceAgainst Bacterial Blight and Blast Diseases into Indian RiceVariety MTU1010

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rice science 2016年第6期23卷 306-316页

作者： k.arunakumari c.v.durgarani v.satturu k.r.sarikonda p.d.r.chittoor b.vutukuri g.s.laha a.p.k.nelli s.gattu m.jamal a.prasadbabu s.hajira r.m.sundaram Institute of Biotechnology Professor Jayashankar Telangana State Agricultural UniversityRajendranagarHyderabad 500030India Andhra Pradesh Rice Research Institute Acharya N.G.Ranga Agricultural UniversityMaruteruWest Godavari District 534122India Agriculture Research Station Acharya N.G.Ranga Agricultural UniversityNellore 524004India Crop Improvement Section ICAR-Indian Institute of Rice ResearchRajendranagarHyderabad 500030India Urmatt Ltd.Wang Chai Chaingrai 57210Thailand

Two major bacterial blight （BB） resistance genes （Xa21 and xa13） and a major gene for blastresistance （Pi54） were introgressed into an Indian rice variety MTU1010 through marker-assistedbackcross breeding. Improved Samba Mahsuri （possessing Xa21 and xa13） and NLR145 （possessingPi54） were used as donor parents. Marker-assisted backcrossing was continued till BC2 generationwherein PCR based functional markers specific for the resistance genes were used for foregroundselection and a set of parental polymorphic microsatellite markers were used for background selectionat each stage of backcrossing. Selected BC2F1 plants from both crosses, having the highest recoveriesof MTU1010 genome （90% and 92%, respectively）, were intercrossed to obtain intercross F1 （ICF1） plants,which were then selfed to generate 880 ICF2 plants possessing different combinations of the BB andblast resistance genes. Among the ICF2 plants, seven triple homozygous plants （xa13xa13Xa21Xa21Pi54Pi54）with recurrent parent genome recovery ranging from 82% to 92% were identified. All the seven ICF2plants showed high resistance against the bacterial blight disease with a lesion lengths of only 0.53–2.28 cm, 1%–5% disease leaf areas and disease scoring values of ‘1’ or ‘3’. The seven ICF2 plants wereselfed to generate ICF3, which were then screened for blast resistance, and all were observed to behighly resistant to the diseases. Several ICF3 lines possessing high level of resistance against BB andblast, coupled with yield, grain quality and plant type on par with MTU1010 were identified and advanced forfurther selection and evaluation.

关键词： gene pyramiding bacterial blight resistance blast resistance rice marker-assistedbackcross breeding