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Effect of post-thermal annealing on the structural and optical properties of ZnO thin films prepared from a polymer precursor

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Chinese physics B 2012年第7期21卷 551-558页

作者： Jijoy.p.Mathew George varghese Jacob Mathew Thin Film Research Laboratory Department of PhysicsSt.Berchmans CollegeChanganasseryKerala 686101India Department of physics Calicut UniversityThenjippalamKeralaIndia

ZnO thin films were synthesised by a new method which uses polyvinyl alcohol （pVA） as the polymer precursor. The films are annealed at different temperatures and for different annealing times. The structural parameters, like grain size, lattice constants, optical band gap, and Urbach energy, depend on the annealing temperature and time. All the films possess tensile strain, which relaxes as the annealing temperature and time increase. The photoluminescence （pL） spectra contain only ultraviolet （UV） peaks at low temperature, but as the annealing temperature and time increase, we observe peaks at the blue and green regions with a variation in the intensities of these peaks with annealing temperature and time.

关键词： stress, band gap, Urbach energy photoluminescence

Options for converting a clone trial of Eucalyptus camaldulensis into a clonal seed orchard considering gain,fertility and effective clone number

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Journal of Forestry Research 2016年第1期27卷 51-57页

作者： R.Kamalakannan M.varghese p.G.Suraj T.Arutselvan ITC Life Sciences and Technology Centre (LSTC) Peenya Industrial Area Phase I

We evaluated a clone trial comprised of 20 ramets each of 40 Eucalyptus camaldulensis clones for growth and fertility at 4 years of age. The clones differed significantly in growth with 65-100 % survival in 38 clones while two clones had low survival （40 and 10 %）. Fecundity was high and fertility variation low, as indicated by the sibling coefficient value （ψ = 1.4） with 55 % of clones contributing 80 % of the fruits. Thinning strategies were considered to convert the clone trial to a clonal seed orchard and enhance both gain and diversity in seed crop. When clones were selected based on growth without con- sidering fertility, truncation selection （to retain clones with higher DBH than the trial mean value） would give 8 % gain, but 59 % reduction in effective population size （Ne）. Gain and predicted diversity （Ne） was highest when ramets were selected in linear proportion to the breeding value of each clone. Mass selection with the same intercept （for DBH） as truncation selection would give a moderate 3 % gain, but over two times higher predicted Ne than trunca- tion selection. When fertility of retained trees was con- sidered after thinning, mass selection would yield 52 % effective contribution from the orchard trees compared to only 30 % contribution from truncation selection and linear thinning. Higher representation of superior clones in linear thinning and mass selection would lead to greater fertilityvariation and over 30 % reduction in effective clone number （Nc） from that predicted （Ne, assuming equal fer- tility among ramets） before thinning.

关键词： Seed orchard Fertility variation Geneticgain Diversity Thinning Eucalyptus

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

Implementation of Interrogation Systems for Fiber Bragg Grating Sensors

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photonic Sensors 2013年第3期3卷 283-288页

作者： Benjamin varghese p. Dinesh KUMAR R. Mittu RAJU K. N. MADHUSOODANAN Department of Instrumentation Cochin University of Science and Technology Cochin lndia

The development of two simple methods for wavelength-optical intensity modulation techniques for fiber Bragg grating （FBG） sensors is presented. The performance is evaluated by measuring the strain and temperature. The first method consists of a narrow band source, an optical circulator, an FBG; and a power meter. The source and Bragg reflected signal from the FBG need to be matched to get linear results with good power levels. The source spectral power levels are very critical in this study. The power reflected from a matched reference FBG is fed into the measuring FBG in the second method. Since the FBGs are matched, the entire power is reflected back initially. During the measurement, the change in the measurand causes the reflected power from the sensing FBG to vary. A costly high resolution spectrum analyzer is required only during the characterization of the FBG and source. The performances of two interrogators are compared by measuring the strain and temperature. In the second method, the strain measurements can be made insensitive to the temperature variation by selecting a source with a flat spectrum at the measurement range. Highlights of these methods are the portability, cost effectiveness and better resolution.

关键词： Fiber Bragg grating interrogator reflected power strain and temperature measurement

Shoreline management plan for a protected but eroding coast along the southwest coast of India

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International Journal of Sediment Research 2017年第4期32卷 495-505页

作者： Varangalil Noujas Kachapally varghese Thomas Nalumakkal Raveendran Ajeesh Research Scholar National Centre for Earth Science Studies 2. Project Scientist ICMAM PD 3. Scientist G & Group Head Coastal Processes Group (Rtd.)National Centre for Earth Science Studies 4. Adjunct FacultyKerala University of Fisheries and Ocean Studies National Institute of Technology Karnataka Engineer (Offshore Structures) WS AtkinsSAIF Zone

Coastal erosion is a serious problem of concern along the southwest(SW) coast of India. Various coastal protection measures have been applied for the recovery of the coast, but the devastating effect of erosion still continues. The present study focuses on a coastal stretch situated on the southern sector of the SW coast of India, where Sundar and Sannasiraj(2006) proposed a groyne field along with an existing seawall to control severe erosion. In order to confirm the net littoral drift of this region and for a preliminary assessment of the performance of the groynes prior to construction of the proposed groyne field, two groynes were initially constructed as a pilot program in 2008-09. periodic monitoring of shoreline position with the two groynes in place was carried out during 2009-14. A shoreline evolution model for the study region was setup, calibrated,and validated using field observations during 2010-11. In addition to traditional shoreline evolution modelling procedures, a profile simulation model was applied for simulating the shoreline behaviour during extreme monsoon seasons. The validated LITpACK model has been used to evaluate the performance of the proposed groyne field in controlling erosion, and the study also considered testing a modified transitional groyne field proposed as an alternative solution to the existing problem, and the modified transitional groyne field was found to be more effective than the prior design. A beach is expected to develop about 30-50 m within the groyne cells during the fair season which enhances the possibility of retaining a minimum beach width of 10 m during monsoon periods.

关键词： Sediment transport Erosion Shoreline change Groyne field LITpACK model

Secure Key Management Based Mobile Authentication in Cloud

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Computer Systems Science & Engineering 2022年第12期43卷 887-896页

作者： S.Shanmuga priya D.Yuvaraj T.Satyanarayana Murthy varghese S.Chooralil S.Navaneetha Krishnan p.Banumathy p.SundaraVadivel Department of Computer Science and Engineering M.I.E.T Engineering CollegeTrichyTamilnaduIndia Department of Computer Science and Engineering Cihan UniversityDuhokKurdistan RegionIraq Department of Computer Science and Engineering Bapatla Engineering CollegeBapatlaAndhra PradeshIndia Department of Computer Science and Engineering Rajagiri School of Engineering and TechnologyKakkanadKeralaIndia Department Electronics and Communication Engineering SACS MAVMM Engineering CollegeMaduraiTamilnaduIndia Department of Information Technology Karaikal Polytechnic CollegeVarichikudy-KaraikalIndia Department of Computer Science and Engineering SACS MAVMM Engineering CollegeMaduraiIndia

Authentication is important to the security of user data in a mobilecloud environment. Because of the server’s user credentials, it is subject toattacks. To maintain data authentication, a novel authentication mechanism is proposed. It consists of three independent phases: Registration, login, and authentication and key agreement. The user registers with the Registration Center (RC)by producing a secret number that isn’t stored in the phone, which protects againstprivileged insider attacks. The user and server generate a nonce for dynamic useridentity and agree on a session secret key for safe communication. The passwordsare not stored on the computer or provided in plain text, they are resistant toreplay, guessing, and stolen verification attacks. The suggested protocol uses aone-way hash function and XOR operations, with the client having remote accessto a large number of servers over a secure communication channel. Concentrateson HMAC and SHA3 for Collision Free Hashing and to overcome length extension attacks. HMACs are substantially less affected by collisions than their underlying hashing algorithms alone. So adding an HMAC to an MD5 or SHA hashwould make it substantially more difficult to break via a rainbow table.

关键词： Registration center SIM IMEI

A Combinatorial Optimized Knapsack Linear Space for Information Retrieval

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Computers, Materials & Continua 2021年第3期66卷 2891-2903页

作者： varghese S.Chooralil Vinodh p.Vijayan Biju paul M.M.Anishin Raj B.Karthikeyan G.Manikandan Rajagiri School of Engineering&Technology Kochi682039India Mangalam College of Engineering Kottayam686631India Department of CSE Viswajyothi College of Engineering&TechnologyVazhakulam686670India School of Computing SASTRA Deemed To Be UniversityThanjavur613401India

Key information extraction can reduce the dimensional effects while evaluating the correct preferences of users during semantic data ***,the classifiers are used to maximize the performance of web-page recommendation in terms of precision and *** recent method disambiguates contextual sentiment using conceptual prediction with robustness,however the conceptual prediction method is not able to yield the optimal ***-dependent terms are primarily evaluated by constructing linear space of context features,presuming that if the terms come together in certain consumerrelated reviews,they are semantically ***,the more frequently they coexist,the greater the semantic dependency ***,the influence of the terms that coexist with each other can be part of the frequency of the terms of their semantic dependence,as they are non-integrative and their individual meaning cannot be *** this work,we consider the strength of a term and the influence of a term as a combinatorial optimization,called Combinatorial Optimized Linear Space Knapsack for Information Retrieval(COLSK-IR).The COLSK-IR is considered as a knapsack problem with the total weight being the“term influence”or“influence of term”and the total value being the“term frequency”or“frequency of term”for semantic data *** method,by which the term influence and the term frequency are considered to identify the optimal solutions,is called combinatorial ***,we choose the knapsack for performing an integer programming problem and perform multiple experiments using the linear space through combinatorial optimization to identify the possible optimum *** is evident from our experimental results that the COLSK-IR provides better results than previous methods to detect strongly dependent snippets with minimum ambiguity that are related to inter-sentential context during semantic data analysis.

关键词： Key information extraction web-page context-dependent nonintegrative combinatorial optimization knapsack

prevalence of internet addiction among college students in the Indian setting:a systematic review and meta-analysis

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General psychiatry 2021年第4期34卷 1-12,I0001-I0009页

作者： Jaison Joseph Abin varghese Vijay VR Manju Dhandapani Sandeep Grover Suresh Sharma Deepika Khakha Sucheta Mann Biji p Varkey College of Nursing Department of Psychiatric NursingPandit Bhagwat Dayal Sharma University of Health SciencesRohtakHaryanaIndia College of Nursing Bhopal Memorial Hospital and Research CentreBhopalIndia College of Nursing All India Institute of Medical SciencesBhubaneswarOrissaIndia National Institute of Nursing Education Post Graduate Institute of Medical Education and ResearchChandigarhIndia Department of psychiatry Post Graduate Institute of Medical Education and ResearchChandigarhIndia College of Nursing All India Institute of Medical SciencesJodhpurRajasthanIndia College of Nursing AIl India Institute of Medical SciencesNew DelhiIndia post Graduate Institute of Medical Sciences Pandit Bhagwat Dayal Sharma University of Health SciencesRohtakHaryanaIndia

Background The internet is an integral part of everyone’s *** going adolescents are highly vulnerable to the misuse of the *** To estimate the pooled prevalence of internet addiction(IA)among college students in *** Literature databases(pubMed,Web of Science,Scopus,EMBASE,psycINFO and Google Scholar)were searched for studies assessing IA using the Young Internet Addiction Test(Y-IAT)among adolescents from India,published in the English language up to December *** included studies from 2010 to 2020 as this is the marked era of momentum in wireless internet connectivity in *** methodological quality of each study was scored,and data were extracted from the published *** prevalence was estimated using the fixed-effects *** bias was evaluated using Egger’s test and visual inspection of the symmetry in funnel *** Fifty studies conducted in 19 states of India estimated the prevalence of IA and the overall prevalence of IA as 19.9%(95%CI:19.3%to 20.5%)and 40.7%(95%CI:38.7%to 42.8%)based on the Y-IAT cut-off scores of 50 and 40,*** estimated prevalence of severe IA was significantly higher in the Y-IAT cut-off points of 70 than 80(12.7%(95%CI:11.2%to 14.3%)vs 4.6%(95%CI:4.1%to 5.2%)).The sampling method and quality of included studies had a significant effect on the estimation of prevalence in which studies using non-probability sampling and low risk of bias(total quality score≥7)reported lower *** overall quality of evidence was rated as‘moderate’based on the Grading of Recommendations Assessment,Development and Evaluation *** Our nationally representative data suggest that about 20%to 40%of college students in India are at risk for *** is a need for further research in the reconsideration of Y-IAT cut-off points among Indian college students.

关键词： internet Google everyone

Delaying clozapine: how long is too long?

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General psychiatry 2020年第2期33卷 88-93页

作者： Tom varghese M KS Jyothi KS Shaji Lekshmi Rita Venugopal Department of psychiatry Government Medical College ThrissurThrissurKeralaIndia Department of psychiatry General Hospital KozhikodeKozhikodeKeralaIndia School of public health University of CaliforniaBerkeleyCaliforniaUSA

Background Although clozapine is the most effective drug for treatment-resistant schizophrenia,its use remains restricted in clinical practice in *** delay in initiating treatment with clozapine and its impact on disease outcome needs *** To identify the implications of delaying clozapine initiation in clinical outcomes among people with treatment-resistant *** Subjects with treatment-resistant schizophrenia,stabilised on clozapine monotherapy,were recruited from the outpatient clinic of a general hospital psychiatry unit offering tertiary care services in Thrissur district,Kerala,India.A retrospective cohort design was employed,and information on duration of illness,total duration of treatment and duration of treatment with clozapine was *** symptom status was measured using the positive and Negative Syndrome *** associated with higher symptom scores were analysed using an independent sample f test,Spearman correlation and multiple linear *** Forty subjects stabilised on long-term clozapine therapy formed the study *** mean dose of clozapine used in the study population was 200 *** mean duration of antipsychotic treatment before starting clozapine was 89.3 months(7.4 years).The duration of treatment before starting clozapine was found to have a significant positive association with the total positive and Negative Syndrome Scale score(correlation coefficient 0.40;p=0.01)and negative symptom score(correlation coefficient 0.33;p=0.04).The multiple regression analysis adjusting for covariates showed that the duration of treatment before starting clozapine was an independent factor associated with a higher negative symptom score in the positive and Negative Syndrome Scale(slope p=0.05;p=0.02;R2=0.27).Conclusion poor treatment outcomes in treatmentresistant schizophrenia could be secondary to a delay in initiating clozapine therapy.

关键词： clozapine starting treatment