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Preparation and characterization of ce_(1-x)Dy_(x-y)Sr_yO_(2-δ) system

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Transactions of Nonferrous Metals Society of china 2014年第2期24卷 393-400页

作者： S.RAMESH K.c.JAMES RAJU c.vishnuvardhan reddy School of Physics University of Hyderabad Department of Physics Osmania University

The effect of dysprosium and strontium on the total ionic conductivity of ceria in the system ce1-xDyx-ySryO2-δ was studied. In this system, few compositions were prepared with x=0.15, y=0.015, 0.03 and 0.045 by modified sol-gel process using maltose and pectin as organic precursors. Rietveld refinement of XRD patterns confirms the cubic structure with space group Fm3m . SEM images show relatively uniform grains with clean and distinct grain boundaries. Four probe Ac impedance measurements were carried out to evaluate the total ionic conductivity in the temperature range of 150-500 ℃ and frequency range of 40 Hz-1 MHz. The composition ce0.85Dy0.12Sr0.03O2-δshows higher electrical conductivity than single-doped ceria samples.

关键词： electrolyte Sr-Dy doping impedance spectroscopy conductivity

Effect of Y on the Properties of Sm-Doped ceria for IT-SOFc Applications

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Journal of Modern Physics 2013年第11期4卷 1499-1503页

作者： V. Venkatesh c. vishnuvardhan reddy Department of Physics Osmania University Hyderabad India

The co-doped ceria-based materials with general composition formula ce0.8-xYxSm0.2O2-δ (x = 0, 0.02, 0.04, 0.06) were prepared through the sol-gel method. The single phase of the prepared materials was confirmed by X-ray diffraction (XRD). The lattice parameters were determined by least square fitting of UNIT cELL programme. The linear variation of lattice parameter with concentration of Y into the samarium doped ceria (SDc) indicates the validity of Vegard’s law. The crystallite size of the samples obtained by using of Scherrer formula is in the range from 34 nm to 49 nm. The thermal expansion studies were carried out by using dilatometric technique in the temperature range from room temperature to 1000°c. It was observed that the thermal expansion increased linearly with increasing temperature for all the samples. The electrical conductivity was studied using impedance spectroscopy. It was observed that the composition ce0.74Y0.06Sm0.2O2-δ showed higher electrical conductivity and lower activation energy (≈1.05 eV) than other compositions in the present investigation. This composition is thus a possible candidate for use the electrolyte in intermediate temperature solid oxide fuel cells (IT-SOFc).

关键词： X-Ray Scanning Electron Microscopy Thermal Expansion Electrical conductivity

Low Temperature Electrical Transport in Double Layered cMR Manganite La1.2Sr1.4Ba0.4Mn2O7

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Advances in Materials Physics and chemistry 2012年第4期2卷 49-52页

作者： Y.S. reddy P. Kistaiah c. vishnuvardhan reddy Department of Physics chaitanya Bharathi Institute of Technology Department of Physics Osmania University Hyderabad

The electrical transport behavior and magnetoresistance (MR) of a polycrystalline double layered manganite La1.2Sr1.4Ba0.4Mn2O7, synthesized by the sol-gel method, are investigated in the temperature range 4.2 K - 300 K. The sample exhibits an insulator-to-metal transition at 87 K (TIM) and the spin-glass (SG)-like behavior is observed below 50 K (TSG). The transport behavior is analyzed in the entire temperature range considering three different regions: paramagnetic insulating region (T>TIM), ferromagnetic metallic region (TSG IM) and antiferromagnetic insulating region (TSG) by fitting the temperature dependent resistivity data to the equations governing the conduction process in the respective temperature regions. The results show that the conduction at T>TIM follows Mott variable range hopping (VRH) process, while the two-magnon scattering process is evidenced at TSG IM which is suppressed with the applied magnetic field of 4 T. The low temperature conductivity data are also fitted with Mott VRH equation. The sample exhibits a large MR (≈45%) over a temperature range???? 5 K – 50 K and it shows ≈32% MR at 5 K with a magnetic field of 0.5 T.

关键词： Layered Manganite Magnetoresistance Transport Behavior Variable Range Hopping Magnon Scattering

Intralenticular metallic foreign body: a case report

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International Journal of Ophthalmology(English edition) 2011年第3期4卷 326-328页

作者： S c reddy Department of Ophthalmology Faculty of MedicineUniversity of Malaya

A case of retained intralenticular iron piece with signs of mild anterior uveitis at the time of presentation is reported in a 45 year-old man. His vision improved with topical cycloplegics and corticosteroids. After six months, his vision deteriorated grossly due to cataract formation. He regained good vision following removal of foreign body, extracapsular extraction with posterior chamber intraocular lens implantation. This case highlights the conservative management of the condition till the patient develops cataract resulting in visual disability; and good visual recovery following cataract surgery with intraocular lens implantation.

关键词： intralenticular foreign body anterior uveitis traumatic cataract penetrating eye injury

Improvising the Self-Healing capabilities of concrete Using Different Pozzolanic Materials and crystalline Admixtures

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 429-439页

作者： A Ravitheja T chandra Sekhara reddy c Sashidhar SVR Engineering college AyyalurNandyalKurnoolAndhra PradeshIndia civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia Jawaharlal Nehru Technological University AnantapurIndia

To analyse the self-healing capacities in terms of mechanical performance of the pozzolanic materials,such as,fly ash,metakaolin and silica fume and crystalline ***-cracked concrete cubes with about 0.05 mm width were exposed to four different environmental conditions at different exposure times in order to determine the effect of temperature and water availability on the self-healing *** the exposure,the control and tested concrete cubes were evaluated for regained strength,void reduction,corrosion inhibition,damp proofing,relative impermeability and *** samples with SF10cA have better cementitious filling and low percentage of voids and water absorption.

关键词： crystalline admixtures pozzolanic materials self-healing

Enhanced saturation magnetization in La^(3+) doped Nico ferrites prepared by sol-gel auto-combustion method

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Journal of Rare Earths 2024年第8期42卷 1546-1554,I0005页

作者： Maddileti Jelli Vidyasagar Thopudurthy Krishna reddy c.V. Department of Physics Rayalaseema UniversityKurnoolA.P518007.Iindia Department of Physics Government PolytechnicRayachotiA.P516269India

Lanthanum doped nickel-cobalt nano ferrites with chemical formula Ni_(0.5)co_(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared using a simple sol-gel auto combustion *** basic structural properties were determined by X-ray diffraction method and the formation of single phased spinel ferrite was *** crystalline size decreased from 25 to 11 nm and lattice parameter a increases with increase of La *** surface morphology of these ferrites was observed by field-emission scanning electron microscopy(FESEM) and agglomerated irregular grains are observed with increase of the rare earth element La ***-dispersive X-ray spectroscopy(EDX) result confirms the presence of the required *** Fourier transform infrared spectroscopy(FTIR) spectrum indicates the formation of the spinel ferrite structure with M-O *** direct band measurements from ultraviolet-visible spectroscopy(UV-Vis) spectroscopy indicate that the direct band gap decreases from 1.39 to 1.19 eV for x=0.05 to x=0.15,then increases to 1.28 eV for x=*** room temperature magnetic properties of these ferrites were studied by a vibrating sample magnetometer(VSM).The enhanced saturation magnetization of 49.73 emu/g is observed for x=0.10 and then saturation magnetizations are gradually decreased for x=0.15 and x=*** the remanent magnetization and coercivity also follow the same trend.

关键词： Ferrites Sol-gel auto combustion La doping Magnetic properties Rare earths

The myth of “minima” and “maxima”,the species of Physalis in the Indian Subcontinent

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植物分类学报 2007年第2期45卷 239-245页

作者： Vatsavaya S RAJU c S reddy K G RAJARAO Department of Botany Kakatiya UniversityWarangal 506009 India Forestry & Ecology Division National Remote Sensing AgencyHyderabad 500008 India Department of Botany Andhra UniversityWaltair 530003 India

The status of the names, Physalis minima L. and P. maxima Mill. (Solanaceae), and their alleged presence on the Indian subcontinent are discussed. The issues of nativity and identity of Linnaean Physalis minima are long-debated while the use of the name P. maxima Mill. and its report from India are recent. The available evidence indicates that the name "P. minima L." is misapplied to two different elements, viz., P. angulata L. and P. lagascae Roem. & Schult. The name Physalis minima L. may be rejected as nomen confusum, for which the paper provides the primary information. As on today, it is submerged under the synonymy of P. angulata L. The correct name for the widely known P. minima is P. lagascae. The name "P. maxima Mill." applied to the escape and naturalized weed in the Indian subcontinent and elsewhere is to be substituted by P. pruinosa L., a name misapplied to P. grisea (Waterf.) M. Martínez.

关键词：酸浆属植物酸浆值植物分类植物命名

Recent Advancements in the Development of Self Healing concrete-A Systematic Review

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Journal of Wuhan University of Technology(Materials Science) 2024年第6期39卷 1449-1460页

作者： A Ravi Theja M Srinivasula reddy Bharat Bhushan Jindal c Sashidhar Assistant Professor in SVR Engineering college NandyalAndhra PradeshIndia Associate Professor of civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia Assistant Professor in School of civil Engineering Shri Mata Vaishno Devi UniversityJammu and KashmirIndia Professor of civil Engineering JNTU College of EngineeringJNTUAAnanthapuramuAndhra PradeshIndia

Mechanical as well as durability properties are pivotal for any type of concrete which gets adversely affected due to cracks that may form due to loading beyond its *** has the intrinsic property to heal itself to some extent but not fully as the passive form of autogenous healing plays an inferior role for a complete repair of a cementitious *** self-healing capabilities can be enhanced by adding chemical admixtures,polymers,and bacteria strains induced calcium carbonate precipitation,*** this paper,the advancements in the development and performance of self-healing concrete using chemical admixtures,polymers,and bacteria strains are *** systematic review includes the available experimental tests and methodologies investigating self-healing efficiency over the last ***,this review focussed on self-healing materials,the ideology,and opinions of those in the construction field on the direction of self-healing concrete for future *** is yet not possible to predict the most appropriate technique,however,a generalized opinion about the effectiveness of the different approaches has been illustrated.

关键词： self-healing cracks bio-based healing chemical additives-based healing

Adverse outcomes in type 1 diabetic pregnant women with proliferative diabetic retinopathy

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International Journal of Ophthalmology(English edition) 2011年第4期4卷 443-446页

作者： c c T Helen I Tajunisah S c reddy Department of Ophthalmology Faculty of Medicine University of Malaya Department of Ophthalmology Faculty of Medicine International Medical University Clinical School

AIM: To report maternal and fetal adverse outcomes, in spite of appropriate treatment and regular follow up, in diabetic pregnant women with proliferative diabetic retinopathy. METHODS: case series of four young pregnant diabetics aged between 20 and 25 years with type 1 diabetes mellitus and proliferative diabetic retrinopathy. RESULTS: The maternal adverse outcomes were abortion in one patient, pre-eclampsia and preterm delivery in one patient, and renal failure requiring dialysis in one patient. The fetal adverse outcomes were neonatal death in one case and premature baby in another case. cONcLUSION: These cases highlight the fact that diabetic pregnant women should be closely followed up by the obstetricians and physicians when they have proliferative retinopathy. The proliferative diabetic retinopathy should be considered as a part of the assessment when counseling a diabetic woman in antenatal check up and also in the follow up visits during pregnancy.

关键词： pregnancy type I diabetes mellitus proliferative diabetic retinopathy vitreous haemorrhage