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Development of image motion compensation system for 1.3 m telescope at Vainu Bappu Observatory

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research in Astronomy and Astrophysics 2020年第1期20卷 93-106页

作者： Sreekanth reddy Vallapureddy ravinder Kumar Banyal Sridharan rengaswamy p Umesh Kamath Aishwarya Selvaraj Indian Institute of Astrophysics

We developed a tip-tilt system to compensate the turbulence induced image motion for the 1.3 m telescope at Vainu Bappu Observatory,at *** instrument is designed to operate at the visible wavelength band(480-700 nm)with a field of view of 1′×1′.The tilt corrected images have demonstrated up to ≈57% improvement in image resolution and a corresponding peak intensity increase by a factor of ≈2.8.A closed-loop correction bandwidth of ≈26 Hz has been achieved with on-sky tests and the root mean square motion of the star image has been reduced by a factor of ~*** results are consistent with theoretical and numerical predictions of wave-front aberrations caused by atmospheric turbulence and image quality improvement expected from a real-time control *** this paper,we present details of the instrument design,laboratory calibration studies and quantify its performance on the telescope.

关键词： adaptive optics atmospheric effects high angular resolution

pCr analysis of Yq microdeletions in infertile males, a study from South India

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Asian Journal of Andrology 2002年第4期4卷 265-268页

作者： S. ramesh Babu M. Swarna p. padmavathi p.p. reddy Institute of Genetics & Hospital for Genetic Diseases Scientist Osmania University Begumpet Hyderabad-500 016 IndiaInstitute of Genetics & Hospital for Genetic Diseases Scientist Osmania University Begumpet Hyderabad-500 016 IndiaInstitute of Genetics & Hospital for Genetic Diseases Scientist Osmania University Begumpet Hyderabad-500 016 IndiaInstitute of Genetics & Hospital for Genetic Diseases Scientist Osmania University Begumpet Hyderabad-500 016 India

AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: polymerase chain reaction (pCr) amplification using Y-specific STS of azoospermia factor (AZF) regions i.e., SY 84 for AZFa, SY 127 for AZFb and SY 254 for AZFc. rESULTS: Of the 20 infertile subjects 3 (15 %), one azoospermic and two oligozoospermic, showed microdeletions in the AZF region of Y-chromosome. CONCLUSION: The frequency of deletions involving AZF region of the Y-chromosome is 15 % in azoospermic and severely oligozoospermic infertile men. pCr amplification of AZF locus is useful for the diagnosis of microdeletions in the Y-chromosome.

关键词： Chromosome Deletion Chromosomes, Human, Y Base Sequence Chromosome Mapping Comparative Study DNA primers Female Gene Frequency Humans India Infertility, Male Male Oligospermia polymerase Chain reaction reference Values research Support, Non-U.S. Gov't Seminal plasma proteins

5-Fluorouracil Loaded Chitosan–pVA/Na^+MMT Nanocomposite Films for Drug release and Antimicrobial Activity

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Nano-Micro Letters 2016年第3期8卷 260-269页

作者： A.Babul reddy B.Manjula T.Jayaramudu E.r.Sadiku p.Anand Babu S.periyar Selvam Department of Chemical Metallurgical and Materials Engineering Tshwane University of Technology CSIR Campus Department of Food process Engineering School of Bioengineering SRM University

In the present study, chitosan and polyvinyl alcohol(pVA) were blended with different concentrations of sodium montmorillonite(Na^+MMT) clay solution by a solvent casting method. X-ray diffraction and transition electron microscope results show that the film properties are related to the co-existence of Na^+MMT intercalation/exfoliation in the blend and the interaction between chitosan–pVA and Na^+MMT. 5-Fluorouracil(5-FU) was loaded with chitosan–pVA/Na^+MMT nanocomposite films for in vitro drug delivery study. The antimicrobial activity of the chitosan–pVA/Na^+MMT films showed significant effect against Salmonella(Gram-negative) and Staphylococcus aureus(Gram-positive), whereas5-FU encapsulated chitosan–pVA/Na^+MMT bio-nanocomposite films did not show any inhibition against bacteria. Our results indicate that combination of a flexible and soft polymeric material with high drug loading ability of a hard inorganic porous material can produce improved control over degradation and drug release. It will be an economically viable method for preparation of advanced drug delivery vehicles and biodegradable implants or scaffolds.

关键词： Biopolymer Chitosan–pVA/Na+MMT Montmorillonite 5-Fluorouracil Drug release Antimicrobial activity

Gas tungsten arc welding of ZrB_2-SiC based ultra high temperature ceramic composites

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Defence Technology（防务技术） 2015年第3期11卷 188-196页

作者： r.V.KrISHNArAO G.MADHUSUDHAN reddy Defence Metallurgical research Laboratory

The difficulty in fabricating the large size or complex shape limits the application of ZrB2-SiC composites. Joining them by fusion welding without or with preheating, controlled cooling under protective gas shield leads to thermal shock failure or porosity at the weld interface. In the present work, a filler material of(ZrB2-SiC-B4C-YAG) composite with oxidation resistance and thermal shock resistance was produced in the form of welding wire. Using the filler, gas tungsten arc welding(GTAW) was performed without employing preheating, post controlled cooling and extraneous protective gas shield to join hot pressed ZrB2-SiC(ZS), and pressureless sintered ZrB2-SiC-B4C-YAG(ZSBY) composites to themselves. The fusion welding resulted in cracking and non-uniform joining without any filler material. The weld interfaces of the composites were very clean and coherent. The Vickers micro-hardness across the weld interface was found to increase due to the increase in the volume % of both SiC and B4C in the filler material. The shear strength of the weld was about 50% of the flextural strength of the parent composite.

关键词：陶瓷基复合材料焊接界面钨极氩弧焊气体保护超高温填充材料 ZrB2 形状复杂

Breeding, introgression and inheritance of delayed gland morphogenesis trait from Gosspium bickii into upland cotton germplasm

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Chinese Science Bulletin 2004年第23期49卷 2470-2476页

作者： reddy Naganagouda College of Agriculture and Biotechnology Zhejiang University Hang- zhou 310029 China

A tri-specific hybrid with delayed pigment gland morphogenesis was obtained by crossing the amphi- diploid of (G. arboreum×G. bickii) F1 and an upland cotton germplasm with pigment gland genotype of Gl2Gl2gl3gl3. The tri-specific hybrid was a typical interspecific hybrid with high sterile, and the chromosome configuration at meiosis MI of pMC was 2n = 52 = 41.04Ⅰ+ 4.54Ⅱ + 0.57Ⅲ + 0.04. The crossover value of bivalent was 1.19. Two fertile plants with objective character were obtained in BC8 population by continuously backcrossing with Gl2Gl2gl3gl3 as recurrent parent to the tri-specific hybrid, and a new upland cotton germplasm, named ABH-0318, with delayed pigment gland morphogenesis trait was developed through selfing and screening. The pigment gland trait of ABH-0318 was stable, and there were almost no pigment glands observed in the dormant seeds, although there were a few pigment glands confined to cotyledon edges, and the gossypol content in the dormant seeds was 0.017% only, being a typical low gossypol cotton type. However, a large quantity of pigment glands emerged in cotyledons and other main organs of plant after seed germination, and the gossypol contents in the upper parts of the plant were similar to that of ordinary glanded cotton types. Genetic analysis demonstrated that the delayed pigment gland morphogenesis trait of this germplasm was controlled by the interaction of the genes located in two pig- ment gland loci, Gl2 and Gl3. Among them, the gene located in locus of Gl2, derived from ***, was dominance to up- land cotton pigment gland alleles, Gl2 and gl2 , but was reces- sive epistatic to another glanded gene Gl3, which was named Gl2 temporarily. While the gene located in the locus of Gl3 b was a recessive gene come from upland cotton.

关键词：基因渗入现象 Gosspium bickii 陆地棉色素腺棉子酚种间杂种

Numerical study of magnetohydrodynamics(MHD)boundary layer slip flow of a Maxwell nanofluid over an exponentially stretching surface with convective boundary condition

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propulsion and power research 2017年第4期6卷 259-268页

作者： p.Bala Anki reddy S.Suneetha N.Bhaskar reddy Department of Mathematics S.A.S.VIT UniversityVellore 632014India Department of Applied Mathematics Yogi Vemana UniversityKadapa 516003India Department of Mathematics S.V.UniversityTirupati 517502India

This paper focuses on a theoretical analysis of a steady two-dimensional magnetohydrodynamic boundary layer flow of a Maxwell fluid over an exponentially stretching surface in the presence of velocity slip and convective boundary *** model is used for a nanofluid,which incorporates the effects of Brownian motion and *** resulting non-linear partial differential equations of the governing flow field are converted into a system of coupled non-linear ordinary differential equations by using suitable similarity transformations,and the resultant equations are then solved numerically by using runge-Kutta fourth order method along with shooting technique.A parametric study is conducted to illustrate the behavior of the velocity,temperature and *** influence of significant parameters on velocity,temperature,concentration,skin friction coefficient and Nusselt number has been studied and numerical results are presented graphically and in tabular *** reported numerical results are compared with previously published works on various special cases and are found to be an in excellent *** is found that momentum boundary layer thickness decreases with the increase of magnetic *** can also be found that the thermal boundary layer thickness increases with Brownian motion and thermophoresis parameters.

关键词： Nano fluid Boundary layer Stretching sheet Magnetohydrodynamics(MHD) Brownian motion Thermophoresis parameter

Influence of Filler Metals in the Control of Deleterious phases During the Multi-pass Welding of Inconel 718 plates

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Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 196-207页

作者： K.Devendranath ramkumar r.Jagat Sai G.Sridhar V.Santhosh reddy p.prabaharan N.Arivazhagan N.Sivashanmugham School of Mechanical & Building Sciences VIT University Department of Mechanical Engineering NITTiruchirappalliIndia

The present study reported the effect of filler metals on the microstructure and mechanical properties of pulsed current gas tungsten arc-welded Inconel 718 plates. Two different filler metals such as ErNiCr-3 and ErNiCrMo-4 were employed for welding Inconel 718. The primary objective of this study is to suppress or eradicate the deleterious phase such as Laves or δ （delta） which is considered to be detrimental to the weld properties. Microstructure examination corroborated the presence of unmixed zone at the HAZ for both the weldments. Tensile test trials envisaged that ErNiCrMo-4 weldments offered better tensile properties compared to ErNiCr-3 weldments, whereas the impact toughness was found to be better for ErNiCr-3 weldments. Line mapping analysis was carried out to study the elemental migration across the weldments. The structure-property relationships of the weldments were arrived at using the combined tech- niques of optical and scanning electron microscopy. Optical and SEM/EDAX analysis showed that there is no prominent occurrence of deleterious phases at the weld zone on employing these filler metals.

关键词： Inconel 718 pulsed current gas tungsten arc welding Mechanical property Deleteriousphase

pMA-SiO_2 catalyzed synthesis of β-keto enol ethers

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Chinese Chemical Letters 2008年第7期19卷 767-770页

作者： p.Srihari S.S.Mandal J.S.S.reddy r.Srinivasa rao J.S.Yadav Organic Division-I Indian Institute of Chemical TechnologyHyderabad 500007India

An efficient conversion of β-diketones into corresponding β-keto enol ethers with catalytic amount of pMA-SiO2 has been achieved.

关键词： β-Keto enol ethers β-Diketones

ZrB_(2)-SiC based composites for thermal protection by reaction sintering of ZrO_(2)+B_(4)C+Si

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Journal of Advanced Ceramics 2017年第4期6卷 320-329页

作者： r.V.KrISHNArAO V.V.BHANUprASAD G.MADHUSUDHAN reddy Defence Metallurgical research Laboratory KanchanbaghHyderabad-500058India

Synthesis and sintering of ZrB_(2)-SiC based composites have been carried out in a single-step pressureless reaction sintering(pLrS)of ZrO_(2),B_(4)C,and Si.Y_(2)O_(3) and Al_(2)O_(3) were used as sintering *** effect of ratios of ZrO_(2)/B_(4)C,ZrO_(2)/Si,and sintering additives(Y_(2)O_(3) and Al_(2)O_(3)),was studied by sintering at different temperatures between 1500 and 1680℃in argon ***_(2),SiC,and YAG phases were identified in the sintered *** as high as 4.2 g/cm^(3),micro hardness of 12.7 Gpa,and flexural strength of 117.6 Mpa were obtained for pLrS *** material was also prepared by pLrS for tungsten inert gas(TIG)welding of the ZrB_(2)-SiC based *** shear strength of the weld was 63.5 *** pLrS ZrB_(2)-SiC composites exhibited:(i)resistance to oxidation and thermal shock upon exposure to plasma flame at 2700℃for 600 s,(ii)thermal protection for Cf-SiC composites upon exposure to oxy-propane flame at 2300℃for 600 s.

关键词： ZrB_(2) SiC reactive sintering synthesis composites