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Radical-mediated hydroalkylation of 2-vinylpyrrolidine derivatives: a versatile entry into indolizidine alkaloids

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Science China Chemistry 2019年第11期62卷 1504-1506页

作者： sankar rao Suravarapu Bettina Peter Philippe Renaud Department of Chemistry and Biochemistry University of Bern

A concise route for the preparation of two simple optically pure indolizidin-5-ones has been *** key chain elongation process was achieved using a triethylborane/catechol mediated hydroalkylation of Boc-protected *** using complementary strategies,these two bicyclic lactams can be alkylated with complete control of the stereochemistry at C(5)and their conversion to a variety of indolizidine alkaloids such as coniceine,indolizidine 209D and 167B,5-epi-indolizidine 249A and monomorine has been reported in the literature.

关键词： alkenes carbohydrogenation radical reaction catechol triethylborane α-iodoesters allylamine

Relationships between the Global General Circulation and the Indian Summer monsoon

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Advances in Atmospheric Sciences 1991年第2期8卷 137-148页

作者： m. sankar-rao V. N. Lvkossov E. m. Volodin A. E. Nikitin A. I. Degtiarev Kusuma G. rao Department of Aerospace Engineering and Centre for Atmospheric Sciences Indian Institute of Science Bangalore 560012 INDIADepartment of Numerical Mathematics USSR Academy of Sciences Moscow USSRDepartment of Numerical Mathematics USSR Academy of Sciences Moscow USSRHydrometeorological Centre Moscow USSRHydrometeorological Centre Moscow USSRCentre for Atmospheric Sciences Indian Institute of Science Bangalore 560012 INDIA

The relationships between the global general circulation and the Indian monsoon during active and break phases are investigated with the help of FGGE IIIb *** was found that the ultralong wave component positive and negative height anomalies over Tibet are associated with active and break monsoon phases respectively. This ultralong wave component has significant effect even upto 22°N over the Indian region which is the monsoon trough region. During a monsoon break, the general circulation was found to be more turbulent in the sense that more waves become *** was observed that during a break, blocking prevails over the Siberian region and cold air advection takes place toward Indian region from Siberian region depressing the temperatures over the Indian region by about 1℃. During the break, the Indian region gets connected with higher latitudes by the south winds blowing from polar Soviet regions to the Indian region. From active to break phase the zonal component weakens by about 25% from Indian ocean area right upto Alaskan region, along the east coast of Asia.

关键词： over In mean

Coating of bioactive glass on magnesium alloys to improve its degradation behavior: Interfacial aspects

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Journal of magnesium and Alloys 2020年第4期8卷 999-1015页

作者： V.S.Yadav m.R.sankar L.m.Pandey centre for the environment indian institute of technology guwahatiassam781039india department of mechanical engineering indian institute of technology guwahatiassam781039india department of mechanical engineering indian institute of technology tirupatiandhra pradesh517506india department of biosciences and bioengineering indian institute of technology guwahatiassam781039india

The preferable mechanical properties of mg alloys along with excellent compatibility with human bone have established their applicability as implant ***,a higher corrosion/degradation rate of mg alloys in body fluids limits its biomedical *** this direction,surface modification and coating are explored as appropriate strategies to mode the degradation rate of mg *** constituents of bioactive glass(BG)provide strength,bio-inertness and bone bonding ***,researchers have explored the coating of BG on mg alloys and investigated chemical,mechanical and biological properties of the coated *** this review,we have made an attempt to compile the literature works done on the coating of BG on mg alloys and its *** interfacial aspects of the coated substrates towards the degradation behavior are *** way forward to further improve the coating characteristics of BG coated mg alloys are remarked.

关键词： Bioactive glass magnesium alloys Adhesion strength Coating thickness Wettability Degradation

e-FILTERS OF mS-ALGEBRAS

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Acta mathematica Scientia 2013年第3期33卷 738-746页

作者： m. Sambasiva rao Department of mathematics M.V.G.R. College of EngineeringChintalavalasa Vizianagaram Andhra Pradesh India-535005

The notion of e-filters is introduced in an mS-algebra and characterized. The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given. The properties of the space of all prime e-filters of an mS-algebra are observed. The concept of D-prime filters is introduced and then a set of equivalent conditions axe derived for a prime e-filter to become a D-prime filter in topological terms.

关键词： mS-algebra e-filter dense element D-filter D-prime filter minimal prime filter Hausdorff space

Numerical Study of Double Diffusive Convection in Partially Heated Vertical Open Ended Cylindrical Annulus

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Advances in Applied mathematics and mechanics 2010年第6期2卷 763-783页

作者： mani sankar Department of mathematics East Point College of Engineering and TechnologyBangalore-560049India

A numerical investigation of laminar natural double diffusive convection in an open ended vertical cylindrical annulus with unheated entry and unheated exit is *** boundary conditions of uniform wall temperature/uniform wall concentration(UWT/UWC)and uniform heat flux/uniform mass flux(UHF/UmF)are *** of dimensionless induced volume rate Q,average Nusselt number Nu and Sherwood number Sh are obtained for air flow under various buoyancy ratio N,Grashof numbers due to heat and mass transfer GrT and Grm,Schmidt number Sc and combinations of unheated entry,heated section and unheated exit *** the flow under consideration is a boundary layer type,the governing partial differential equations was discretized to a linear system of equations by the use of an implicit finite difference *** nonlinear convective terms are approximated by second upwind difference method for the numerical *** numerical results reveal that the presence of unheated entry and unheated exit severely affects the heat and mass transfer *** numerical solutions are found to approach asymptotically the closed form solutions for fully developed ***,the present numerical results are validated with the existing solutions for pure thermal convection and are found to be in good agreement.

关键词： Discrete heating cylindrical annulus upwind difference doubles diffusive convection buoyancy ratio

Wireless Sensor Network-based Detection of Poisonous Gases Using Principal Component Analysis

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Computer Systems Science & Engineering 2023年第1期44卷 249-264页

作者： N.Dharini Jeevaa Katiravan S.m.Udhaya sankar Easwari Engineering College Chennai600089India Velammal Engineering College Chennai600066India Velammal Institute of Technology Chennai601204India

This work utilizes a statistical approach of Principal Component Ana-lysis(PCA)towards the detection of methane(CH_(4))-Carbon monoxide(CO)Poi-soning occurring in coal mines,forestfires,drainage systems *** the CH_(4) and CO emissions are very high in closed buildings or confined spaces during oxi-dation *** methane and carbon monoxide are highly toxic,colorless and odorless *** of the gases have their own toxic levels to be *** during their combined presence,the toxicity of the either one goes unidentified may be due to their low levels which may lead to an *** using PCA,the correlation of CO and CH_(4) data is carried out and by identifying the areas of high correlation(along the principal component axis)the explosion suppression action can be triggered earlier thus avoiding adverse effects of massive ***-less Sensor Network is deployed and simulations are carried with heterogeneous sensors(Carbon monoxide and methane sensors)in NS-2 mannasim *** rise in the value of CO even when CH_(4) is below the toxic level may become hazardous to the people *** our proposed methodology will detect the combined presence of both the gases(CH_(4) and CO)and provide an early warning in order to avoid any human losses or toxic effects.

关键词： Wireless sensor network principal component analysis carbon monoxide-methane poisoning confined spaces

Quaternary tectonic control on channel morphology over sedimentary low land:A case study in the Ajay-Damodar interfluve of Eastern India

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Geoscience Frontiers 2015年第6期6卷 927-946页

作者： Suvendu Roy Abhay sankar Sahu Department of Geography University of Kalyani

The style of active tectonic on the deformation and characterization of fluvial landscape has been investigated on three typical skrike-slip fault zones of the Ajay-Damodar Interfluve（ADI） in Eastern India through field mapping,structural analysis and examination of digital topography（ASTER-30 m）,multispectral imageries,and Google Earth images,Channel morphology in Quaternary sediment is more deformed than Cenozoic lateritic tract and igneous rock system by the neotectonic activities,The structural and lithological controls on the river system in ADI region are reflected by distinct drainage patterns,abrupt change in flow direction,offset river channels,straight river lines,ponded river channel,marshy lands,sag ponds,palaeo-channels,alluvial fans,meander cutoffs,multi-terrace river valley,incised compressed meander,convexity of channel bed slope and knick points in longitudinal profile,Seven morphotectonic indices have been used to infer the role of neotectonic on the modification of channel morphology,A tectonic index map for the ADI region has been prepared by the integration of used morphotectonic indices,which is also calibrated by Bouguer gravity anomaly data and field investigation.

关键词： Active tectonic Skrike-slip fault Channel morphology morphotectonic indices Neotectonic map

Thermoluminescence study of rare earth ion (Dy^(3+)) doped LiF:mg crystals grown by EFG technique

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Journal of Rare Earths 2012年第7期30卷 641-646页

作者： Pooja Seth Shruti Aggarwal S m rao University School of Basic and Applied Science Guru Gobind Singh Indraprastha University Department of Physics Punjabi University

This work describes investigation of radiation dosimetry characteristics of magnesium （mg） doped lithium fluoride （LiF） crystals co-doped with different concentrations of dysprosium （Dy）. These crystals were grown by edge defined film fed crystal growth （EFG） tech- nique. Thermoluminescence （TL） measurements were made on as grown （AG） and annealed （AN） crystals after they were irradiated with a gamma dose of 15 Gy. The influence and advantage of optimized Dy^3＋ concentration in enhancing the thermoluminescence （TL） properties of LiF：mg samples were discussed. The normalized peak height of the annealed crystals was nearly 3 times that of the as grown crystals for the particular concentration samples irradiated with Co6~ gamma source showed linearity up to 10 Gy. Thermoluminescence signal observed over a period of one month showed negligible fading. Thermoluminescence glow curve structure of optimized phosphor remained stable for higher doses of gamma rays of 103 Gy. Glow curve was analyzed using computer glow curve deconvolution （CGCD） method and trapping parame- ters were calculated.

关键词： thermoluminescenea rare earth ions annealing edge defined film fed growth technique

Hybrid Authentication Using Node Trustworthy to Detect Vulnerable Nodes

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Computer Systems Science & Engineering 2023年第4期45卷 625-640页

作者： S.m.Udhaya sankar S.Thanga Revathi R.Thiagarajan Department of Information Technology Velammal Insitutue of TechnologyChennai601204India Department of Networking and Communication SRM Institute of Science and TechnologyKattankulathur603203India Department of Information Technology Prathyusha Engineering CollegeThiruvallur602025India

An ad-hoc sensor network(ASN)is a group of sensing nodes that transmit data over a wireless link to a target node,direct or indirect,through a series of *** becomes a high-risk group for several security exploits due to the sensor node’s limited *** threats are more challenging to protect against than external *** nodes are grouped,and calculate each node’s trust *** trust level is the result of combining internal and external trust *** heads(CH)are chosen based on the anticipated trust *** communications are then digitally signed by the source,encoded using a key pair given by a trustworthy CH,decoded by the recipient,and supervised by *** authenticates the technique by identifying the presence of both the transmitter and the *** approach looks for a trustworthy neighboring node that meets the trust threshold condition to authenticate the key *** companion node reaffirms the node’s reliability by getting the public-key *** seeking sensor node and the certification issuer node must have a close and trusting *** results of the proposed hybrid authentication using a node trustworthy(HANT)system are modeled and tested,and the suggested approach outperforms conventional trust-based approaches in throughput,latency,lifetime,and vulnerability methods.

关键词： Ad hoc sensor network wireless security clustering cryptography key management