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Steric Effect of Alkyl Substituted Piperidin-4-one Oximes for Corrosion Control of Mild Steel in H_2SO_4 Medium

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物理化学学报 2012年第2期28卷 399-406页

作者： SENTHILKUMAR Annamalai THARINI kumaravel SETHURAMAN Mathur Gopalakrishnan Department of Chemistry H.H The Rajah's CollegePudukkottai-622 001TamilnaduIndia Department of Chemistry Raja Saraboji Government CollegeThanjavur-613 005TamilnaduIndia Department of Chemistry Gandhigram Rural Institute(DU)Gandhigram-624 302TamilnaduIndia

Three synthesized piperidin-4-one oximes,3-ethyl-2,6-diphenyl-piperidin-4-one oxime(A),1-methyl-3-isopropyl-2,6-diphenyl-piperidin-4-one oxime(B),and 3-isopropyl-2,6-diphenyl-piperidin-4-one oxime(C),were tested at different concentrations to determine their ability to inhibit corrosion of mild steel in 1 mol.L-1 H2SO4 and measured by a mass loss method(at various temperatures),polarization and impedance measurements,X-ray diffraction(XRD),scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDS),and a quantum chemical method.The synergistic influence of compounds A,B and C with iodides has also been evaluated.All three compounds show good inhibition efficiency in the following order:A>B>C.Compounds A,B and C were found to physically adsorb on the surface of mild steel while obeying the Temkin isotherm.Polarization measurements indicated that these compounds behave as a mixed mode inhibitor.XRD and SEM with EDS studies revealed the formation of a protective barrier on the mild steel surface by these oximes.The electron donating ability of the studied molecules was tested using semi empirical methods.The studies revealed that the oxime nitrogen,the piperidine moiety,and the phenyl ring assist largely in corrosion control.The studies also showed that the steric crowding by the alkyl group in the piperidine ring affects the inhibitor efficiency.Further,it is interesting to note that all of the studied compounds exhibit synergism with iodide ions.

关键词：摘要编辑部编辑工作读者

STABILITY RESULTS OF RANDOM IMPULSIVE SEMILINEAR DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2014年第4期34卷 1055-1071页

作者： M.GOWRISANKAR P.mohankumar A.VINODKUMAR Department of Mathematics Annapoorana Engineering College Salem- 636308Tamil NaduIndia Department of Mathematics Arupadai Veedu Institute of Technology Chennai- 636104 Department of Mathematics PSG College of Technology Coimbatore- 641004Tamil NaduIndia

In this paper, we study the existence, uniqueness, continuous dependence, Ulam stabilities and exponential stability of random impulsive semilineax differential equations under sufficient condition. The results are obtained by using the contraction mapping principle. Finally an example is given to illustrate the applications of the abstract results.

关键词： semilinear differential equations random impulses stability, Hyers-Ulam stability Hyers-Ulam-Rassias stability exponential stability contraction principle

Flicker and thermal noise in an n-channel underlap DG FinFET in a weak inversion region

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Journal of Semiconductors 2013年第2期34卷 31-36页

作者： Sudhansu Kumar Pati Hemant Pardeshi Godwin Raj N mohankumar Chandan Kumar Sarkar Nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur University SKP College of Engineering TiruvannamalaiTamilnadu-606 611India

We propose an analytical model for drain current and inversion charge in the subthreshold region for an underlap DG FinFET by using the minimum channel potential method, i.e., the virtual source. The flicker and thermal noise spectral density models are also developed using these charge and current models expression. The model is validated with already published experimental results of flicker noise for DG FinFETs. For an ultrathin body, the degradation of effective mobility and variation of the scattering parameter are considered. The effect of device parameters like gate length Lg and underlap length Lun on both flicker and thermal noise spectral densities are also analyzed. Increasing Lg and Lun, increases the effective gate length, which reduces drain current, resulting in decreased flicker and thermal noise density. A decrease of flicker noise is observed for an increase of frequency, which indicates that the device can be used for wide range of frequency applications.

关键词： flicker noise thermal noise ultrathin body virtual source underlap DG FinFET

Effect of underlap and gate length on device performance of an AlInN/GaN underlap MOSFET

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Journal of Semiconductors 2012年第12期33卷 16-22页

作者： Hemant Pardeshi Sudhansu Kumar Pati Godwin Raj N mohankumar Chandan Kumar Sarkar Nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur University SKP Engineering College

We investigate the performance of an 18 nm gate length AIInN/GaN heterostructure underlap double gate MOSFET, using 2D Sentaurus TCAD simulation. The device uses lattice-matched wideband Al0.83In0.17N and narrowband GaN layers, along with high-k Al2O3 as the gate dielectric. The device has an ultrathin body and is designed according to the ITRS specifications. The simulation is done using the hydrodynamic model and interface traps are also considered. Due to the large two-dimensional electron gas （2DEG） density and high velocity, the maximal drain current density achieved is very high. Extensive device simulation of the major device performance metrics such as drain induced barrier lowering （DIBL）, subthreshold slope （SS）, delay, threshold voltage （Vt）, Ion/Ioff ratio and energy delay product have been done for a wide range of gate and underlap lengths. Encouraging results for delay, Ion, DIBL and energy delay product are obtained. The results indicate that there is a need to optimize theIoff and SS values for specific logic design. The proposed AlInN/GaN heterostructure underlap DG MOSFET shows excellent promise as one of the candidates to substitute currently used MOSFETs for future high speed applications.

关键词： MOS-HEMT underlap heterostructure ultrathin body interface traps effective mass

EXISTENCE, UNIQUENESS AND STABILITY OF RANDOM IMPULSIVE FRACTIONAL DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2016年第2期36卷 428-442页

作者： A.Vinodkumar K.Malar M.Gowrisankar P.mohankumar Department of Mathematics Amrita School of EngineerringAmrita Vishwa Vidyapeetham University Department of Mathematics Erode Arts and Science College Department of Mathematics Annapoorana Engineering College Department of Mathematics A.C.T College of Engineering and Technology

In this article, we study the existence, uniqueness, stability through continuous dependence on initial conditions and Hyers-Ulam-Rassias stability results for random impulsive fractional differential systems by relax... 详细信息

关键词： Fractional differential systems random impulses stability Hyers-Ulam stability Hyers-Ulam-Rassias stability

Microstructures and mechanical properties of nanocrystalline NiTi intermetallics formed by mechanosynthesis

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 80-87页

作者： S.Arunkumar P.kumaravel C.Velmurugan V.Senthilkumar Vinayaka Mission's Kimpananda Variyar Engineering College Salem 636308TamilnaduIndia Institute of Road and Transport Technology Erode 638316TamilnaduIndia National Institute of Technology Trichy 620015TamilnaduIndia

The formulation of nanocrystallinc NiTi shape memory alloys has potential effects in mechanical stimulation and medical im- plantology. The present work elucidates the effect of milling time on the product＇s structural characteristics, chemical composition, and mi- crohardness for NiTi synthesized by mechanical alloying for different milling durations. Increasing the milling duration led to the formation of a nanocrystalline NiTi intermetallic at a higher level. The formation of nanocrystalline materials was directed through cold fusion, fractur- ing, and the development of a steady state, which were influenced by the accumulation of strain energy. In the morphological study, uninter- rupted cold diffusion and fracturing were visualized using transmission electron microscopy. Particle size analysis revealed that the mean particle size was reduced to -93 μm after 20 h of milling. The mechanical strength was enhanced by the formation of a nanocrystalline in- termetallic phase at longer milling time, which was confirmed by the results of Vickers hardness analyses.

关键词： nickel-titanium shape memory alloy lattice strain nano-crystalline mechanical alloying microstructural characterization

A new approach to extracting the RF parameters of asymmetric DG MOSFETs with the NQS effect

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Journal of Semiconductors 2013年第11期34卷 31-35页

作者： Sudhansu Kumar Pati Kalyan Koley Arka Dutta N mohankumar Chandan Kumar Sarkar Nano Device Simulation Laboratory Electronics and Telecommunication Engineering Department Jadavpur University SKP College of Engineering Tiruvannamalai

In analog circuit design an important parameter, from the perspective of superior device performance, is linearity. The DG MOSFET in asymmetric mode operation has been found to present a better linearity. In addi- tion to that it provides, at the discretion of analog circuit designer, an additional degree of freedom, by providing independent bias control for the front and the back gates. Here a non-quasi-static （NQS） small signal model for DGMOSFET with asymmetric gate bias is proposed for extracting the parameters of the device using TCAD sim- ulations. The parameters extracted here for analysis are the intrinsic front and back gate to drain capacitance, Cgal and Cgd2, the intrinsic front and back distributed channel resistance, Rgdl and Rgd2 respectively, the transport de- lay, rm, and the inductance, Lsd. The parameter extraction model for an asymmetric DG MOSFET is validated with pre-established extracted parameter data, for symmetric DG MOSFET devices, from the available literature. The device simulation is performed with respect to frequency up to 100 GHz.

关键词： asymmetric DGMOSFET RF modeling small signal analysis parameter extraction

A 2DEG charge density based drain current model for various Al and In molefraction mobility dependent nano-scale AlInGaN/AlN/GaN HEMT devices

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Journal of Semiconductors 2013年第4期34卷 24-29页

作者： Godwin Raj Hemant Pardeshi Sudhansu Kumar Pati N mohankumar Chandan Kumar Sarkar Nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur UniversityKolkata-700 032India SKP Engineering College TiruvannamalaiTamilnadu-606 611India

We present a two-dimensional electron gas （2DEG） charge-control mobility variation based drain cur- rent model for sheet carrier density in the channel. The model was developed for the AIInGaN/A1N/GaN high- electron-mobility transistor. The sheet carrier density model used here accounts for the independence between the Fermi levels Ef and ns along with mobility for various AI and In molefractions. This physics based ns model fully depends upon the variation of El, u0, the first subband E0, the second subband El, and as. We present a physics based analytical drain current model using ns with the minimum set of parameters. The analytical resuks obtained are compared with the experimental results for four samples with various molefraction and barrier thickness. A good agreement between the results is obtained, thus validating the model.

关键词： 2DEG Fermi level AlInGaN

Performance evaluation of cone penetrometer device for measuring the subsoil compaction in mulched plots

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International Journal of Agricultural and Biological Engineering 2013年第3期6卷 19-27页

作者： R.Thiyagarajan G.C.Jayashree A.P.mohankumar P.Vijayakumary Agricultural Engineering College and Research Institute Tamil Nadu Agricultural UniversityKumulur 621712Tamil NaduIndia Department of Agricultural Engineering University of Agricultural SciencesBangalore-560065KarnatakaIndia Agricultural Engineering College and Research Institute Tamil Nadu Agricultural UniversityCoimbatore 641003Tamil NaduIndia

Soil exhibits layers of extreme compaction from both natural causes and wheel traffic.These compaction layers impede root growth,thereby reducing the plants capacity to obtain water during drought.Subsoil tillage is a remedy for adverse soil compaction that results in improved conditions for crop growth.Mechanical disturbance of subsoil increases water holding capacity and reduces impedance to root penetration.Vertical mulching is a technique that can be used to partially alleviate soil compaction within the critical root zones of deep rooted crops.A study was conducted by placing raw and composted coir pith using a two row subsoil coir pith mulching machine in three different soil depths(250,350,and 450 mm)at the three application rates of 15 t/ha,20 t/ha,and 25 t/ha and the effect of soil strength was investigated.The experiment was conducted for a rainfed cotton crop.The soil strength profile was recorded in all the treatments.The cone penetrometer resistance was measured for each increment of 10 mm and recorded manually from a digital force indicator during maturity stages of crop in all the treatment plots.The cone penetrometer resistance was measured directly on the row and the cone index was computed.Deep placement of mulch reduced the soil strength as compared to shallow placement.The lower soil strength(0.5 kPa to 0.8 kPa)in the loosened and mulched zone provided an impedance free zone for the root to proliferate.The rapid increase in cone index values at depths immediately below the respective depth of placement(250,350 and 450 mm)of raw and composted coir pith mulch indicated that the existence of undisturbed soil profile below the mulched zone which could be potential limiting factor for root development.

关键词： soil strength raw coir pith composted coir pith cone penetrometer cone index subsoil compaction