Synthesis, deposition and characterization of tin selenide thin films by thermal evaporation technique

R. Indirajith,T.P. Srinivasan,K. Ramamurthi,R. Gopalakrishnan 한국물리학회 2010 Current Applied Physics Vol.10 No.6

Tin selenide alloy was synthesized by following simple chemical reaction method, at comparatively lower temperature of 100 ℃, from alkaline medium using SnCl2.2H2O and selenium as source materials. Powder X-ray diffraction analysis reveals that the particle size of the synthesized product is in nanometer scale. Using the reaction product as source material, the SnSe films were deposited on glass substrates at room temperature, 150 ℃, 250 ℃, 350 ℃ and 450 ℃. Structural, elemental, optical, surface morphological and electrical properties of the as deposited films were studied by X-ray diffraction, Energy Dispersive X-ray Analysis, UV-Vis-NIR, Scanning Electron Microscopy and Hall effect measurement techniques and the relevant details have been obtained.

Characterization on electron beam evaporated α-MoO3 thin films by the influence of substrate temperature

R. Sivakumar,R. Gopalakrishnan,M. Jayachandran,C. Sanjeeviraja 한국물리학회 2007 Current Applied Physics Vol.7 No.1

Electrochromic molybdenum oxide (MoO3) thin lms were prepared by electron beam evaporation technique using the dry MoO3pellets. The lms were deposited on glass and uorine doped tin oxide (SnO2:F or FTO) coated glass substrates at dierent substratetemperatures like room temperature (RT, 30.C), 100.C and 200 .C. The inuence of substrate temperature on the structural, surfacerhombic phase MoO 3 (a-MoO3) withh110i preferred orientation. The laser Raman scattering spectrum shows the polycrystalline natureof MoO 3 lms deposited at 200.C. The Raman-active band at 993 cm. 1 is corresponding to MoO stretching mode that is associatedwith the unique character of the layered structure of orthorhombic MoO3. Needlelike morphology was observed from the SEM anal-ysis. The energy band gap of MoO3 lms was evaluated which lies between 2.8 and 2.3 eV depending on the substrate temperature andsubstrates. The decrease in band gap value with increasing substrate temperature is owing to the oxygen-ion vacancies. The absorptionedge shift shows the coloration eect on the lms.

Large Vocabulary Natural Language Continuous Speech Recognition

Bakis, L.R.,Bellegarda, J.,Brown, P.F.,Burshtein, D.,Das, S.K.,Souza, P.V.ed,Gopalakrishnan, P.S.,Jelinck, F.,Kanevsky, D.,Mercer, R.L.,Nadas, A.J.,Nahamoo, D.,Picheny, M.A. 서울대학교 어학연구소 1990 語學硏究 Vol.26 No.4

The present paper describes our current research on automatic speech recognition of continuously read sentences from a naturally-occurring corpus: office correspondence. The recognition system combines features from our current isolated-word recognition system and from our previously developed continuous speech recognition systems. It consists of an acoustic processor, an acoustic channel model, a language model, and a linguistic decoder. Some new features in the recognizer relative to our isolated-word speech recognition system include the use of a fast match to rapidly prune to a manageable number the candidates considered by the detailed match, multiple pronunciations of all function words, and modelling of interphone coarticulatory behavior. To date, we have recorded training and test data from a set of 10 males talkers. The test data consist of 50 sentences drawn from spontaneously generated memos covered by a 5000 word vocabulary. The perplexity of the test sentences was found to be 93 ; none of the sentences were part of the data used to generate the language model. Preliminary (speaker-dependent) recognition results on these takers yielded an average word error rate of 11.0%.

Detection Mechanism on Vehicular Adhoc Networks (VANETs) A Comprehensive Survey

Shobana, Gopalakrishnan,Arockia, Xavier Annie R. International Journal of Computer ScienceNetwork S 2021 International journal of computer science and netw Vol.21 No.6

VANET is an upcoming technology with an encouraging prospect as well as great challenges, specifically in its security. This paper intends to survey such probable attacks and the correlating detection mechanisms that are introduced in the literature. Accordingly, administering security and protecting the owner's privacy has become a primary argument in VANETs. To furnish stronger security and preserve privacy, one should recognize the various probable attacks on the network and the essence of their behavior. This paper presents a comprehensive survey on diversified attacks and the recommended unfolding by the various researchers which concentrate on security services and the corresponding countermeasures to make VANET communications more secure.

Explicit incremental matrices for the postbuckling analysis of thin plates with small initial curvature

Jayachandran, S. Arul,Gopalakrishnan, S.,Narayanan, R. Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.12 No.3

The postbuckling behaviour of thin plates is an important phenomenon in the design of thin plated structures. In reality plates possess small imperfections and the behaviour of such imperfect plates is of great interest. To numerically study the postbuckling behaviour of imperfect plates explicit incremental or secant matrices have been presented in this paper. These matrices can be used in combination with any thin plate element. The secant matrices are shown to be very accurate in tracing the postbuckling behaviour of thin plates.

Novel Synthesis of bis Acetylated Hybrid Pyrazoles as Potent Anticandidiasis Agents

Kanagarajan, V.,Ezhilarasi, M. R.,Gopalakrishnan, M. Korean Chemical Society 2011 대한화학회지 Vol.55 No.2

Bis acetylated hybrid pyrazoles 을 합성하여 이들 화합물에 대해 녹는점, 원소분석, MS, FT-IR, one-dimensional $^1H,-$ 및 $^{13}C$-NMR로 분석하였다. 합성한 화합물들에 대해 in vitro 항균활성을 Candida sp. namely Candida albicans, Candida glabrata, Candida parapsilosis, Candida dubliniensis 및 Candida tropicali 균에 대해 수행하였다. Pyrazoles의 페닐고리에 작용기($-CH_3$, $-OCH_3$, -F, -Cl, 및 Br)가 있는 화합물은 Candida species에 대해서 강한 활성을 나타내었다. A new series of bis acetylated hybrid pyrazoles were synthesized and characterized by their melting point, elemental analysis, MS, FT-IR, one-dimensional $^1H$, and $^{13}C$ NMR spectroscopic data. All the synthesized compounds were tested for their in vitro antifungal activities against Candida sp. namely Candida albicans, Candida glabrata, Candida parapsilosis, Candida dubliniensis and Candida tropicalis. A close inspection of the in vitro anticandidal activity profile in differently electron donating ($CH_3$ and $OCH_3$) and electron withdrawing (-F, -Cl, and Br) functional group substituted phenyl rings of novel hybrid pyrazoles exerted strong anticandidal activity against all the tested Candida species.

Disperser-induced bacterial disintegration of partially digested anaerobic sludge for efficient biomethane recovery

Banu, J. Rajesh,Kannah, R. Yukesh,Kavitha, S.,Gunasekaran, M.,Yeom, Ick Tae,Kumar, Gopalakrishnan Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.347 No.-

<P><B>Abstract</B></P> <P>The present study highlights the options to enhance the methane potential of partially digested anaerobic sludge using disperser-induced bacterial disintegration. Floc dispersion with no biomass disintegration was achieved at a disperser-specific energy input of 9.5 kJ/kg TS. The outcomes of both sole bacterial disintegration (S-BD) and disperser-induced bacterial disintegration (D-BD) were assessed in terms of changes in lysate, biopolymer release and increase in biodegradability and methane generation. A higher lysate solubilization of about 22.4% was achieved in D-BD compared to S-BD (11.3%), indicating the efficiency of floc dispersion prior to bacterial disintegration. The biochemical methane result implies that D-BD shows higher methane potential of 0. 279 gCOD/gCOD. Considering the overall outcome achieved in this study, disperser-induced bacterial disintegration is proved to be an effective disintegration process for enhanced biodegradation and higher methane production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Disintegration of digested sludge is a promising technique for bioenergy generation. </LI> <LI> Floc dispersion was achieved at lesser disperser input energy of 9.5 kJ/kg TS. </LI> <LI> A higher lysate solubilization of 22.4% was achieved in floc dispersed sample. </LI> <LI> Biopolymer release of floc dispersed sludge was higher (1379.8 and 394.2 mg/L) </LI> <LI> Result of methane reveals the effect of floc dispersion prior to disintegration. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Structural damage detection through longitudinal wave propagation using spectral finite element method

Kumar, K. Varun,Saravanan, T. Jothi,Sreekala, R.,Gopalakrishnan, N.,Mini, K.M. Techno-Press 2017 Geomechanics & engineering Vol.12 No.1

This paper investigates the damage identification of the concrete pile element through axial wave propagation technique using computational and experimental studies. Now-a-days, concrete pile foundations are often common in all engineering structures and their safety is significant for preventing the failure. Damage detection and estimation in a sub-structure is challenging as the visual picture of the sub-structure and its condition is not well known and the state of the structure or foundation can be inferred only through its static and dynamic response. The concept of wave propagation involves dynamic impedance and whenever a wave encounters a changing impedance (due to loss of stiffness), a reflecting wave is generated with the total strain energy forked as reflected as well as refracted portions. Among many frequency domain methods, the Spectral Finite Element method (SFEM) has been found suitable for analysis of wave propagation in real engineering structures as the formulation is based on dynamic equilibrium under harmonic steady state excitation. The feasibility of the axial wave propagation technique is studied through numerical simulations using Elementary rod theory and higher order Love rod theory under SFEM and ABAQUS dynamic explicit analysis with experimental validation exercise. Towards simulating the damage scenario in a pile element, dis-continuity (impedance mismatch) is induced by varying its cross-sectional area along its length. Both experimental and computational investigations are performed under pulse-echo and pitch-catch configuration methods. Analytical and experimental results are in good agreement.

Comparative study on damage identification from Iso-Eigen-Value-Change contours and smeared damage model

N. Lakshmanan,B.K. Raghuprasad,N. Gopalakrishnan,R. Sreekala,G.V. Rama Rao 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.6

The paper proposes two methodologies for damage identification from measured natural frequencies of a contiguously damaged reinforced concrete beam, idealised with distributed damage model. The first method identifies damage from Iso-Eigen-Value-Change contours, plotted between pairs of different frequencies. The performance of the method is checked for a wide variation of damage positions and extents. The method is also extended to a discrete structure in the form of a five-storied shear building and the simplicity of the method is demonstrated. The second method is through smeared damage model, where the damage is assumed constant for different segments of the beam and the lengths and centres of these segments are the known inputs. First-order perturbation method is used to derive the relevant expressions. Both these methods are based on distributed damage models and have been checked with experimental program on simply supported reinforced concrete beams, subjected to different stages of symmetric and un-symmetric damages. The results of the experiments are encouraging and show that both the methods can be adopted together in a damage identification scenario.

Comparative study on damage identification from Iso-Eigen-Value-Change contours and smeared damage model

Lakshmanan, N.,Raghuprasad, B.K.,Gopalakrishnan, N.,Sreekala, R.,Rama Rao, G.V. Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.6

The paper proposes two methodologies for damage identification from measured natural frequencies of a contiguously damaged reinforced concrete beam, idealised with distributed damage model. The first method identifies damage from Iso-Eigen-Value-Change contours, plotted between pairs of different frequencies. The performance of the method is checked for a wide variation of damage positions and extents. The method is also extended to a discrete structure in the form of a five-storied shear building and the simplicity of the method is demonstrated. The second method is through smeared damage model, where the damage is assumed constant for different segments of the beam and the lengths and centres of these segments are the known inputs. First-order perturbation method is used to derive the relevant expressions. Both these methods are based on distributed damage models and have been checked with experimental program on simply supported reinforced concrete beams, subjected to different stages of symmetric and un-symmetric damages. The results of the experiments are encouraging and show that both the methods can be adopted together in a damage identification scenario.