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Science China(Life Sciences) 2010年第2期53卷 234-240页

作者： rajasekaran r rao Sethumadhavan Bioinformatics Division School of BiotechnologyChemical and Biomedical EngineeringVellore Institute of Technology

In this study,we identified the most deleterious nsSNP in rB1 gene through structural and functional properties of its protein (prB) and investigated its binding affinity with *** of 956 SNPs,we investigated 12 nsSNPs in coding region in which three of them (SNPids rs3092895,rs3092903 and rs3092905) are commonly found to be damaged by I-Mutant 2.0,SIFT and PolyPhen *** this effort,we modeled the mutant prB proteins based on these deleterious *** a comparison of total energy,stabilizing residues and rMSD of these three mutant proteins with native prB protein,we identified that the major mutation is from Glutamic acid to Glycine at the residue position of 746 of ***,we compared the binding efficiency of both native and mutant prB (E746G) with *** found that mutant prB has less binding affinity with E2F-2 as compared to native *** is due to sixteen hydrogen bonding and two salt bridges that exist between native type and E2F-2,whereas mutant type makes only thirteen hydrogen bonds and one salt bridge with *** on our investigation,we propose that the SNP with an id rs3092905 could be the most deleterious nsSNP in rB1 gene causing retinoblastoma.

关键词： retinoblastoma non synonymous SNP rB1 gene prB E2F-2

Separation of Metallic and Semiconducting Single-Walled Carbon Nanotubes Through Fluorous Chemistry

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Nano research 2009年第3期2卷 183-191页

作者： Sandeep Ghosh N.r.rao Chemistry and Physics of Materials Unit DST unit on Nanoscience and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientifi c ResearchJakkur P.O.Bangalore-560064India Solid State and Structural Chemistry Unit Indian Institute of ScienceBangalore-560012India

Separation of metallic from semiconducting single-walled carbon nanotubes has been a major challenge for some time and some previous efforts have resulted in partial success. We have accomplished the separation effectively by employing fl uorous chemistry wherein the diazonium salt of 4-heptadecafl uorooc tylaniline selectively reacts with the metallic nanotubes present in the mixture of nanotubes. The resulting fl uoroderivative was extracted in perfl uorohexane leaving the semiconducting nanotubes in the aqueous layer. The products have been characterized by both raman and electronic absorption spectroscopy. The method avoids the cumbersome centrifugation step required by some other procedures.

关键词： Carbon nanotubes metallic semiconducting fl uorous separation

Quantum counterfactuality with identical particles

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Communications in Theoretical Physics 2023年第6期75卷 59-65页

作者： Vinod N rao Anindita Banerjee r Srikanth Theoretical Sciences Division Poornaprajna Institute of Scientific ResearchBidalurBengaluru—562164India Graduate Studies Manipal Academy of Higher EducationManipal—576104India Centre of Development of Advanced Computing Corporate Research and DevelopmentPune—411008India

Quantum self-interference enables the counterfactual transmission of information,whereby the transmitted bits involve no particles traveling through the *** this work,we show how counterfactuality can be realized even when the self-interference is replaced by interference between identical ***,the facet of indistinguishability called forth here is associated with first-order coherence,and is different from the usual notion of indistinguishability associated with the(anti-)commutation relations of mode *** an experimental perspective,the simplest implementation of the proposed idea can be realized by slight modifications to existing protocols for differential-phase-shift quantum key distribution or interaction-free measurement.

关键词： quantum cryptography counterfactuality indistinguishability

A novel approach for speaker diarization system using TMFCC parameterization and Lion optimization

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Journal of Central South University 2017年第11期24卷 2649-2663页

作者： V.Subba ramaiah r.rajeswara rao Mahatma Gandhi Institute of Technology KokapetHyderabadTelangana 500075India Jawaharlal Nehru Technological University Kakinada KakinadaAndhra Pradesh 535002India

In audio stream containing multiple speakers, speaker diarization aids in ascertaining "who speak when". This is an unsupervised task as there is no prior information about the speakers. It labels the speech signal conforming to the identity of the speaker, namely, input audio stream is partitioned into homogeneous segments. In this work, we present a novel speaker diarization system using the Tangent weighted Mel frequency cepstral coefficient(TMFCC) as the feature parameter and Lion algorithm for the clustering of the voice activity detected audio streams into particular speaker groups. Thus the two main tasks of the speaker indexing, i.e., speaker segmentation and speaker clustering, are improved. The TMFCC makes use of the low energy frame as well as the high energy frame with more effect, improving the performance of the proposed system. The experiments using the audio signal from the ELSDSr corpus datasets having three speakers, four speakers and five speakers are analyzed for the proposed system. The evaluation of the proposed speaker diarization system based on the tracking distance, tracking time as the evaluation metrics is done and the experimental results show that the speaker diarization system with the TMFCC parameterization and Lion based clustering is found to be superior over existing diarization systems with 95% tracking accuracy.

关键词： speaker diarization Mel frequency cepstral coefficient i-vector extraction Lion algorithm

A note on constrained M-estimation and its recursive analog in multivariate linear regression models

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Science China Mathematics 2009年第6期52卷 1235-1250页

作者： rao Calyampudi r WU YueHua Advanced Institute of Mathematics Statistics and Computer ScienceUniversity of HyderabadHyderabadAndhra PradeshIndia Department of Mathematics and Statistics York University4700 Keele StreetTorontoOntario M3J 1P3Canada

In this paper, the constrained M-estimation of the regression coefficients and scatter parameters in a general multivariate linear regression model is considered. Since the constrained M-estimation is not easy to compute, an up-dating recursion procedure is proposed to simplify the computation of the estimators when a new observation is obtained. We show that, under mild conditions, the recursion estimates are strongly consistent. In addition, the asymptotic normality of the recursive constrained M-estimators of regression coefficients is established. A Monte Carlo simulation study of the recursion estimates is also provided. Besides, robustness and asymptotic behavior of constrained M-estimators are briefly discussed.

关键词： asymptotic normality breakdown point consistency constrained M-estimation influence function linear model M-estimation recursion estimation robust estimation

High-Velocity Projectile Impact Behaviour of Friction Stir Welded AA7075 Thick Plates

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Defence Technology（防务技术） 2023年第11期29卷 153-163页

作者： r.Praveen S.r.Koteswara rao G.Selvakumar r.Damodaram Department of robotics and Automation Karpaga Vinayaga College of Engineering and TechnologyChengalpattu603308TamilNaduIndia Department of Mechanical Engineering Sri Sivasubramaniya Nadar College of EngineeringChennai603110TamilNaduIndia

In this study, high velocity impact behaviour of friction stir welded AA7075-T651 25 mm thick plates were investigated using a 7.62 mm × 51 mm lead core and 7.62 mm × 39 mm steel core projectiles. Prior to ballistic trails, mechanical and metallurgical properties of friction stir welded AA 7075-T651 25 mm thick plates were studied. Microstructural and hardness studies revealed that friction stir welds constituted three distinct regions namely Weld Nugget(WN), Thermo-Mechanically Affected Zone(TMAZ) and Heat Affected Zone(HAZ). Base Material(BM) and all three weld regions were ballistically tested as per military standard NIJ.0108.01 using lead and steel core bullets at maximum permissible velocities of 830 ± 20 and 700 ± 30 m/s, respectively. It has been found that base material(AA7075-T651)and all three weld regions of 25 mm thick plates were able to resist perforation by both types of projectiles used. However depth of penetration has been found to increase from BM to WN, HAZ and TMAZ for both types of projectiles. In all cases steel core projectiles caused higher depth of penetration compared to those caused by lead core projectiles. TMAZs of the friction stir welds were found to be the weakest zone. The fracture that occurred in the base material was spall fragmentation indicating brittle failure, whereas all zones of friction stir welded AA7075-T651 targets with a front petalling, indicating ductile failure. The post-ballistic tested samples showed no significant change in the microstructure of the BM and WN. On the other hand, TMAZ and HAZ showed severe grain deformation in the direction of projectile penetration, and the formation of adiabatic shear bands(ASB). This work showed that 25 mm thick friction stir welded AA7075-T651 joints responded well to ballistic impact loads, making them a good choice for light combat vehicles.

关键词： Aluminum alloy Thick plate Friction stir welding Ballistic performance Depth of penetration

Effect of Post Cryorolling Treatments on Microstructural and Mechanical Behaviour of Ultrafine Grained Al-Mg-Si Alloy

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Journal of Materials Science & Technology 2014年第10期30卷 998-1005页

作者： P.Nageswara rao Dharmendra Singh r.Jayaganthan Department of Metallurgical and Materials Engineering Indian Institute of Technology Roorkee

To investigate the effect of post cryorolling treatments on simultaneous enhancement in strength and ductility of ultrafine grained material （UFG）, AI 6061 alloy was subjected to cryorolling followed by warm rolling （Cr ＋ Wr） and compared with cryorolling followed by short annealing （Cr ＋ SA） at the same temperature. Transmission electron microscopy （TEM） was used to characterize the microstructural features of the processed material. The mechanical properties were investigated through Vickers hardness testing and tensile testing at room temperature. TEM, X-ray diffraction （XrD） and differential scanning calorimetry （DSC） were used to investigate the precipitation evolution in UFG material. results indicated that the alloy subjected to Cr ＋ Wr has shown improved mechanical properties （114 HV, ultimate tensile strength （UTS）： 350 MPa） as compared to that in the case of Cr ＋ SA （105 HV, UTS： 285 MPa）. The size of the precipitates observed in Cr ＋ Wr sample after peak ageing treatment is finer than that of peak aged Cr ＋ SA sample. The UTS of peak aged Cr ＋ Wr sample （UTS： 390 MPa） was found to be higher than that of peak aged Cr ＋ SA sample （UTS： 355 MPa）, without decrease in ductility.

关键词： Aluminium alloy Cryorolling Warm rolling Short annealing Mechanical properties Differential scanning calorimetry (DSC)

Growth Kinetics of Nanocrystals and Nanorods by Employing Small-angle X-ray Scattering (SAXS) and Other Techniques

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Journal of Materials Science & Technology 2008年第4期24卷 615-627页

作者： Kanishka BISWAS Neenu VArGHESE C.N.r.rao Chemistry and Physics of Materials Unit DST Nanoscience Unit and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientific ResearchJakkur P.O.Bangalore 560064India Solid State and Structural Chemistry UnitIndian Institute of ScienceBangalore 560012India Chemistry and Physics of Materials Unit DST Nanoscience Unit and CSIR Centre of Excellence in ChemistryJawaharlal Nehru Centre for Advanced Scientific ResearchJakkur P.O.Bangalore 560064India

In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering （SAXS）, transmission electron microscopy （TEM） along with other physical techniques. The study includes growth kinetics of gold nanocrystals formed by the reduction of HAuCl4 by tetrakis（hydroxymethyl） phosphonium chloride in aqueous solution, of CdSe nanocrystals formed by the reaction of cadmium stearate and selenium under solvothermal conditions, and of ZnO nanorods formed by the reaction of zinc acetate with sodium hydroxide under solvothermal conditions in the absence and presence of capping agents. The growth of gold nanocrystals does not follow the diffusion-limited Ostwald ripening, and instead follows a Sigmoidal rate curve. The heat change associated with the growth determined by isothermal titration calorimetry is about 10 kcal·mol^-1 per I nm increase in the diameter of the nanocrystals. In the case of CdSe nanocrystals also, the growth mechanism deviates from diffusion-limited growth and follows a combined model containing both diffusion and surface reaction terms. Our study of the growth kinetics of uncapped and poly（vinyl pyrollidone）（PVP）-capped ZnO nanorods has yielded interesting insights. We observe small nanocrystals next to the ZnO nanorods after a lapse of time in addition to periodic focusing and defocusing of the width of the length distribution. These observations lend support to the diffusion-limited growth model for the growth of uncapped ZnO nanorods. Accordingly, the time dependence on the length of uncapped nanorods follows the L3 law as required for diffusion-limited Ostwald ripening. The PVP-capped nanorods, however, show a time dependence, which is best described by a combination of diffusion （L^3） and surface reaction （L^2） terms.

关键词： Growth kinetics Gold nanocrystals CdSe nanocrystals ZnO nanorods Small angle X-ray scattering Transmission electron microscopy Ostwald ripening and sigmoidal growth

response Analysis of Tension-Based Tension Leg Platform Under Irregular Waves

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China Ocean Engineering 2016年第4期30卷 603-614页

作者： D.S.Bhaskara rao r.Panneer Selvam Department of Ocean Engineering Indian Institute of Technology Madras

Tension Leg Platform（TLP） is a hybrid structure used as oil drilling and production facility within water depths of 1200 m. The extension of this TLP concept to deeper waters is a challenge and warrants for some innovative design concepts. In this paper, a relatively new concept of TLP which is christened as Tension-Based Tension Leg Platform（TBTLP） and patented by Srinivasan（1998） has been chosen for study. response analysis of TLP with one tension base under irregular waves for three different sea states has been performed using hydrodynamic tool ANSYS？ AQWA？. results are reported in terms of raos, response spectrums for surge, heave and pitch degrees of freedom from which spectral statistics have been obtained. The statistics of TBTLP have been compared with TLPs（without tension base） for two different water depths to highlight the features of the new concept. The effect of viscous damping and loading effects on the raos are also investigated.

关键词： Tension-Based Tension Leg Platform irregular waves time domain response response amplitudeoperators spectrum statistics coupled analysis

Microstructures and impact toughness behavior of Al 5083 alloy processed by cryorolling and afterwards annealing

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 759-769页

作者： Dharmendra Singh P.Nageswara rao r.Jayaganthan Department of Metallurgical and Materials Engineering Indian Institute of Technology RoorkeeRoorkee-247667India

The influence of rolling at liquid nitrogen temperature and annealing on the microstructure and mechanical properties of Al 5083 alloy was studied in this paper. Cryorolled samples of Al 5083 show significant improvements in strength and hardness. The ultimate tensile strength increases up to 340 MPa and 390 MPa for the 30% and 50% cryorolled samples, respectively. The cryorolled samples, with 30% and 50% reduction, were subjected to Charpy impact testing at various temperatures from 190℃ to 100℃. It is observed that increasing the percentage of reduction of samples during cryorolling has significant effect on decreasing impact toughness at all temperatures by increasing yield strength and decreasing ductility. Annealing of samples after cryorolling shows remarkable increment in impact toughness through recovery and recrystallization. The average grain size of the 50% cryorolled sample （14 μm） after annealing at 350℃ for 1 h is found to be finer than that of the 30% cryorolled sample （25 μm）. The scanning electron microscopy （SEM） analysis of fractured surfaces shows a large-size dimpled morphology, resembling the ductile fracture mechanism in the starting material and fibrous structure with very fine dimples in cryorolled samples corresponding to the brittle fracture mechanism.

关键词： aluminum alloys cryorolling annealing microstructure impact toughness recovery recrystallization