Highly flexible memristive devices based on MoS₂ quantum dots sandwiched between PMSSQ layers

Perumal Veeramalai, Chandrasekar,Li, Fushan,Guo, Tailiang,Kim, Tae Whan The Royal Society of Chemistry 2019 Dalton Transactions Vol.48 No.7

<P>This paper reports a facile, cost effective method that uses an aqueous hydrothermal process for synthesizing two-dimensional molybdenum disulphide (MoS2) monolayer quantum dots (QDs) and their potential applications in flexible memristive devices. High-resolution transmission electron microscopy and atomic force microscopy images confirmed that the diameters of the synthesized MoS2 QDs with irregular shapes were in the range between 3 and 6 nm; their thicknesses were confirmed to lie between 1.0 and 0.8 nm, a clear indication that a monolayer of MoS2 QDs had been synthesized. Photoluminescence (PL) and time-resolved PL spectra of the MoS2 QDs revealed a strong emission in the blue region with a slower decay constant. Memristive devices fabricated by incorporating MoS2 QDs between poly(methylsilsesquioxane) ultrathin layers, which had been deposited on poly(ethylene terephthalate), demonstrated a high ON-OFF current ratio of ∼10<SUP>4</SUP>, stable retention, and excellent endurance in the relaxed state; these devices were also demonstrated to function properly during bending and in a bent state. The flexible memristive devices demonstrated an OFF state with a very low current of 10<SUP>−6</SUP> A. These results clearly show that ultrathin two-dimensional QDs have promising applications in high-performance flexible memristive devices.</P>

Continuous potentiometric sensor for electrogenerated mediator in solution: rationalization by the RDE and flow cell methods

( Perumal Silambarasan ),( Govindan Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Very recently, an in-situ determination of electron mediators’ quantification was developed by potentiometric sensor method. Here in, a rationalization of potentiometric sensor by RDE (rotating disc electrode) and flow cell methods were optimized. First, electrochemical generation of [Co(I)(CN)5]4- in 10 M KOH solution was done by Nafion324 membrane divided electrochemical cell. The electrogenerated solution monitored by current and potential using RDE and flow cell with different RPM (rotation per minute) and flow rate by cyclic voltammetry (CV) method. By comparing the peak potential and peak current change, validation of a suitable method was derived for potentiometric sensor in determination of electrogenerated electron mediator in solution.

Miniature Inverted-repeat Transposable Elements (MITEs) as Valuable Genomic Resources for the Evolution and Breeding of Brassica Crops

( Perumal Sampath ),( Tae Jin Yang ) 한국육종학회 2014 Plant Breeding and Biotechnology Vol.2 No.4

Transposable elements (TEs) play important roles in structural and functional diversification, genome enlargement, and speciation in plant genome. Their derivatives or small non-autonomous TEs play important roles in the alteration of homologous genes by epigenetic control or structural modification. The miniature inverted-repeat transposable element (MITE) is one of the representative non-autonomous class II TEs. MITEs include high copy members that are widely distributed and in close association with genic regions, which make MITEs useful targets and resources for in-depth understanding of genome evolution, as well as practical applications in molecular breeding. Here, we discuss the important features of MITEs, such as the identification tools of a novel MITE family, structural characterization, distribution pattern analysis, and impact on evolution in highly duplicated Brassica genome. We show the characteristics, copy numbers, and distribution patterns of 20 novel MITE families, and represent their putative roles in the evolution of the triplicated Brassica genome. We also introduce our MITE database, and discuss the utility of MITEs for developing MITE-derived markers that are useful for molecular breeding of Brassica crops.

Consideration of bulk concentration change in transient current of rotating disc electrode for E’ reaction (quasi- reversible): Theoretical simulation and experimental validation

( Perumal Silambarasan ),심왕근,( G. Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

In the rotating disc electrode transient current, the bulk concentration considered as constant due to the non-electrolyzed solution. But, change in bulk concentration occurred in many paired electrolysis process with electrolysis time that is used for many applications. In this work, the transient current and concentration change in the rotating disc electrode (RDE) system is explained by solving the convection and diffusion equation for a quasi- reversible electron transfer. The mathematical models are solved by applying orthogonal collocation method. This approach enables us the current response and concentration change with electrolysis time. Experimental results compared with the theoretically simulated data. A good correlation found between the current and the RDE system. The possible expression derived in the present work for bulk concentration change can be used for continuous electrolysis system.

Potentiometric flow sensor for in-situ determination of electrogenerated electron mediator in an paired electrolysis cell

( Perumal Silambarasan ),( G. Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Instead of off-line potentiometric titrations for electron mediator’s quantification, in-situ determination can be an accurate method. Here in, we have initiated to monitor the electrochemically prepared mediator [Co(I)(CN)₅]^4- by in-situ flow sensor cell coupled with paired electrolysis cell. First, cyclic voltammetry peak current for a standard redox couple Fe(II)/Fe(III) with different concentration ratios was used in the flow sensor cell to check the developed method. Then the Chemically prepared [Co(I)(CN)₅]^4- in presence of 10 M KOH at different concentrations were analyzed by UV-Visible and potentiometric titration method and compared. Finally, the chemically prepared different concentration of Co(I) do monitored using selected electrode under the inert atmosphere by flow sensor cell. The resulted calibration plot used to derive the concentration of [Co(I)(CN)₅]^4-.

Effect of bimetal coated membrane electrode divided Clarks cell for online air pollutant sensor: A study by electrochemical removal at electroscrubbing plant

( Perumal Silambarasan ),( G. Muthuraman ),문일식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

In the present investigation, Ag and Ag-Ni or Ag-Co metal ions coated Nafioni324 membrane electrode divided cell was developed and compared in amperometric detection of air pollutants. Ag and Ag-Ni or Ag-Co were chemically coated on the Nafion324 membrane and used in filter press technique to make a cell with one side having 0.1 M KOH electrolyte and gas phase cathodic half-cell. Based on the cyclic voltammetry and linear sweep voltammetry analyses, the gas phase redox peak was fixed for detection of selected gas pollutants. Then sense a selected air pollutants by amperometric method at different suitable applied voltage. The current with different feed concentration were compared with in-situ FTIR gas analyzer concentration and derived calibration plot.

Review on Molecular and Chemopreventive Potential of Nimbolide in Cancer

Perumal Elumalai,Jagadeesan Arunakaran 한국유전체학회 2014 Genomics & informatics Vol.12 No.4

Cancer is the most dreaded disease in human and also major health problem worldwide. Despite its high occurrence, theexact molecular mechanisms of the development and progression are not fully understood. The existing cancer therapybased on allopathic medicine is expensive, exhibits side effects; and may also alter the normal functioning of genes. Thus, anon-toxic and effective mode of treatment is needed to control cancer development and progression. Some medicinal plantsoffer a safe, effective and affordable remedy to control the cancer progression. Nimbolide, a limnoid derived from the neem(Azadirachta indica) leaves and flowers of neem, is widely used in traditional medical practices for treating various humandiseases. Nimbolide exhibits several pharmacological effects among which its anticancer activity is the most promising. Theprevious studies carried out over the decades have shown that nimbolide inhibits cell proliferation and metastasis of cancercells. This review highlights the current knowledge on the molecular targets that contribute to the observed anticanceractivity of nimbolide related to induction of apoptosis and cell cycle arrest; and inhibition of signaling pathways related tocancer progression.

Estimating the compressive strength of HPFRC containing metallic fibers using statistical methods and ANNs

Perumal, Ramadoss,Prabakaran, V. Techno-Press 2020 Advances in concrete construction Vol.10 No.6

The experimental and numerical works were carried out on high performance fiber reinforced concrete (HPFRC) with w/cm ratios ranging from 0.25 to 0.40, fiber volume fraction (Vf)=0-1.5% and 10% silica fume replacement. Improvements in compressive and flexural strengths obtained for HPFRC are moderate and significant, respectively, Empirical equations developed for the compressive strength and flexural strength of HPFRC as a function of fiber volume fraction. A relation between flexural strength and compressive strength of HPFRC with R=0.78 was developed. Due to the complex mix proportions and non-linear relationship between the mix proportions and properties, models with reliable predictive capabilities are not developed and also research on HPFRC was empirical. In this paper due to the inadequacy of present method, a back propagation-neural network (BP-NN) was employed to estimate the 28-day compressive strength of HPFRC mixes. BP-NN model was built to implement the highly non-linear relationship between the mix proportions and their properties. This paper describes the data sets collected, training of ANNs and comparison of the experimental results obtained for various mixtures. On statistical analyses of collected data, a multiple linear regression (MLR) model with R2=0.78 was developed for the prediction of compressive strength of HPFRC mixes, and average absolute error (AAE) obtained is 6.5%. On validation of the data sets by NNs, the error range was within 2% of the actual values. ANN model has given the significant degree of accuracy and reliability compared to the MLR model. ANN approach can be effectively used to estimate the 28-day compressive strength of fibrous concrete mixes and is practical.

Monitoring the chlorobenzene gas using an electrochemical gas sensor during mediated electrochemical degradation at room temperature

( Perumal Silambarasan ),문일식 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.0

Interaction of Zwitterionic and Ionic Monomers with Graphene Surfaces

Perumal, Suguna,Raji, Atchudan,Cheong, In Woo American Chemical Society 2018 Langmuir Vol.34 No.23

<P>Measurement of the interaction force between two materials provides important information on various properties, such as adsorption, binding, or compatibility for coatings, adhesion, and composites. The interaction forces of zwitterionic and ionic monomers with graphite platelets (G) and reduced graphene oxide (rGO) surfaces were systematically investigated by atomic force microscopy (AFM) in air and water. The monomers examined were 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate (MPC), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBE), [2-(acryloyloxy)ethyl]trimethylammonium chloride (ATC), and 2-methyl-2-propene-1-sulfonic acid sodium (MSS). The AFM studies revealed that MSS and SBE monomers with sulfonate units have stronger interaction forces with G surface in air and that MPC and ATC monomers with quaternary ammonium units have higher interaction forces in water. In the case of rGO surface, the monomers with quaternary ammonium units showed stronger interactions regardless of the medium. These interactions could be rationalized by the interaction mechanism between the monomers with graphene surfaces, such as cation−π for MPC and ATC and anion−π for MSS and SBE. Overall, cation−π interactions were effective in water, whereas anion−π interactions are effective in air with G surface. The adhesion values of MPC, SBE, ATC, and MSS on rGO were lower than the values measured on G surface. Among the monomers, MPC showed the highest dispersibility for aqueous graphene dispersions. Further, the adsorption of MPC on G and rGO surfaces was verified by high-resolution transmission electron microscopy and X-ray diffraction patterns.</P> [FIG OMISSION]</BR>