Bias–stress-induced threshold voltage shift dependence of negative charge trapping in the amorphous indium tin zinc oxide thin-film transistors

Nguyen, Cam Phu Thi,Trinh, Thanh Thuy,Dao, Vinh Ai,Raja, Jayapal,Jang, Kyungsoo,Le, Tuan Anh Huy,Iftiquar, S M,Yi, Junsin Institute of Physics 2013 Semiconductor science and technology Vol.28 No.10

<P>Indium tin zinc oxide (ITZO)-based thin-film transistors (TFTs) were fabricated by dc magnetron sputtering in Ar + O<SUB>2</SUB> reactive gas, at room temperature. We present the effect of post-deposition annealing of ITZO thin films on the oxygen vacancies and on the characteristics of TFT devices. When the annealing temperature was increased from room temperature to 350 °C, the resistivity of ITZO film increased from 2.05 × 10<SUP>1</SUP> to 2.60 × 10<SUP>3</SUP> Ω cm and the interface trap density (<I>N</I><SUB>t</SUB>) of the TFTs reduced from 3.18 × 10<SUP>13</SUP> to 4.83 × 10<SUP>11</SUP> cm<SUP>−2</SUP>. The TFT with the ITZO film which was annealed at 350 °C showed a very small shift in turn-on voltage, even after applying positive bias stress of +12 V for 10<SUP>4</SUP> s. The current–voltage characteristics of 350 °C annealing temperature sample indicated that these TFTs were in an enhanced mode of transistor operation with a high on-to-off current ratio of ∼1.26 × 10<SUP>6</SUP>, high field-effect mobility of 14.17 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>, and low subthreshold slope of 1.23 V/dec. The trapping time reduced from 3720 to 1546 s as the annealing temperature increased from room temperature to 350 °C. These results suggest that thermal annealing played an important role in reducing defects as well as improvement in stability of the TFTs.</P>

Spectral characterization of a pteridine derivative from cyanide-utilizing bacterium Bacillus subtilis - JN989651

S. Durairaju Nisshanthini,Antony K. Teresa Infanta S.,Duraisamy Senthil Raja,Karuppannan Natarajan,M. Palaniswamy,Jayaraman Angayarkanni 한국미생물학회 2015 The journal of microbiology Vol.53 No.4

Soil and water samples were collected from various regionsof SIPCOT and nearby Vanappadi Lake, Ranipet, Tamilnadu,India. Based on their colony morphology and their stabilityduring subculturing, 72 bacteria were isolated, of which 14isolates were actinomycetes. Preliminary selection was carriedout to exploit the ability of the microorganisms to utilizesodium cyanate as nitrogen source. Those organismsthat were able to utilize cyanate were subjected to secondaryscreening viz., utilization of sodium cyanide as the nitrogensource. The oxygenolytic cleavage of cyanide is dependenton cyanide monooxygenase which obligately requires pterincofactor for its activity. Based on this, the organisms capableof utilizing sodium cyanide were tested for the presence ofpterin. Thin layer chromatography (TLC) of the cell extractsusing n-butanol: 5 N glacial acetic acid (4:1) revealed that10 out of 12 organisms that were able to utilize cyanide hadthe pterin-related blue fluorescent compound in the cellextract. The cell extracts of these 10 organisms were subjectedto high performance thin layer chromatography (HPTLC)for further confirmation using a pterin standard. Based onthe incubation period, cell biomass yield, peak height andarea, strain VPW3 was selected and was identified as Bacillussubtilis. The Rf value of the cell extract was 0.73 which wasconsistent with the 0.74 Rf value of the pterin standardwhen scanned at 254 nm. The compound was extracted andpurified by preparative High Performance Liquid Chromatography(HPLC). Characterization of the compound wasperformed by ultraviolet spectrum, fluorescence spectrum,Electrospray Ionization-Mass Spectrometry (ESI-MS), andNuclear Magnetic Resonance spectroscopy (NMR). The compoundis proposed to be 6-propionyl pterin (2-amino-6-propionyl-3H-pteridin-4-one).

Hepatoprotective and antioxidant effects of Monochoria vaginalis against acetaminophen-induced hepatotoxicity in rats

S Palani,S Raja,K Sakthivel,K Devi,B Senthil Kumar 경희대학교 융합한의과학연구소 2010 Oriental Pharmacy and Experimental Medicine Vol.10 No.1

The present study was aimed to investigate the hepatoprotective and antioxidant activities of ethanol extract from Monochoria vaginalis (250 mg/kg and 500 mg/kg B/W) on acetaminophen (APAP)induced rat hepatic injury. Monochoria vaginalis is a traditional medicinal plant that is commonly used to treat and improve liver conditions in India and other Asian countries. The development of hepatotoxicity induced by APAP is promoted by oxidative stress. APAP treated group significantly (P < 0.01) elevated the serum enzymatic levels like glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, alkaline phosphatase (SALP), total bilirubin and malondialdehyde (MDA), which were restored towards normalization significantly (P < 0.01)thanol extract of yonochoria vagin is (EEMV). In addition, the EEMV significantly (P < 0.01)elevated the decreased level of total protein and antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase and reduced glutathione. Apart from these, histopathological changes also showed the protective nature of the EEMV against APAP induced hepatic damage in liver tissues. The activity of EEMV at 500 mg/kg B/W was comparable to the standard drug silymarin (25 mg/kg B/W). In conclusion, these data suggest that the EEMV possess hepatoprotective and antioxidant effects against APAP-induced hepatotoxicity and oxidative stress in rats.

Antioxidant potential of aerial part of Asclepias curassavica. Linn (Family-Asclepiadaceae)

Raja, S,Ahamed, KFH Nazeer,Kumar, V,Mukherjee, Kakali,Bandyopadhyay, Arun,Mukherjee, Pulok K Kyung Hee Oriental Medicine Research Center 2005 Oriental pharmacy and experimental medicine Vol.5 No.2

Asclepias curassavica. Linn, an erect, simple (or) much branched perennial herb with a somewhat woody base, belonging to the family Asclepiadaceae. It has been reported to have multiple pharmacological effect of anti-inflammatory, cardiotonic, anticancer, anthelmintic and to treat piles and gonorrhoea. It is to be expected that several activities might be related to a possible antioxidant action from this plant. The hydro alcoholic extract of Asclepias curassavica was tested in vitro for its antioxidant activities, such as DPPH radical, nitric oxide radical, superoxide anion radical, lipid peroxidation assay, hydroxyl radical, reducing power, and total phenol content. The extract exhibited scavenging potential with $IC_{50}$ value of $8.7\;{\mu}g/ml,\;198.4\;{\mu}g/ml\;and\;21.7\;{\mu}g/ml$ for DPPH, nitric oxide and superoxide anion radicals. The values were found to higher than those of Vitamin-C, rutin, and curcumin, as standards. The extract showed 50% protection at the dose of $134.2\;{\mu}g/ml\;and\;41.4\;{\mu}g/ml$ in lipid peroxidation as well as deoxyribose degradation, those values more to that of standard, vitamin E $(IC50\;values,\;119.2\;{\mu}g/ml\;and\;32.5\;{\mu}g/ml,\;respectively)$. The reducing power of the extract depends on the concentration and amount of extract. Since a significant amount of polyphenol could be detected by the equivalent to $0.0495\;{\mu}g$ of pyrocatechol from 1 mg of extract. It can be concluded that hydro alcoholic extract of aerial part of Asclepias curassavica could be considered as potent antioxidant, which makes it suitable for the prevention of human disease.

An approximation scheme for the numerical solution of hiv infection of CD T-cells using Chebyshev wavelets

S. RAJA BALACHANDAR,S.G. VENKATESH,S.K.AYYASWAMY,K. BALASUBRAMANIAN,K. KRISHNAVENI 장전수학회 2019 Proceedings of the Jangjeon mathematical society Vol.22 No.4

In this paper, the Chebyshev wavelets method for solving a model for HIV infection of CD4+ T-cells is studied. The properties of Chebyshev wavelets and their operational matrices are rst presented and then are used to convert into algebraic equations. Also the convergence and error analysis for the proposed technique is discussed. Illustrative examples are given to demonstrate the valid- ity and applicability of the technique. The eciency of the proposed method is compared with other traditional methods and it is observed that the Chebyshev wavelet method is more convenient than the other methods in terms of applica- bility, eciency, accuracy, error and computational eort.

Wind Tunnel Studies on Autonomous Hybrid VTOL UAV with Wing Morphing Technology

Raja S,Shanmugam Palaniswamy,Dwarakanathan D,Parammasivam K M 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10

CSIR-NAL has designed VTOL winged UAV to address hybrid unmanned vehicle requirements. The hybrid UAV’s aerodynamics and propulsion characteristics have been validated through wind tunnel test and to achieve better flight performance, a morphing wing technology was developed using multi-axis robotic concept. The multi axis controller was realized for the morphed wing mechanism of VTOL UAV through LMA and PID controller. The control motion simulation was performed in MATLAB. The experimental results were obtained on a typical UAV morphing wing travel in multi-axis with a dedicated test rig. The controller successfully detected the IMU sensors and adopted with APM (Autopilot mode) instrumentation, simulating the flight condition. The controller with the Robotic Coupling System for WTT was operationalized at NAL’s MART Tunnel facility. This approach generates a simple model with a relatively high degree of accuracy, which can be easily integrated on to the wind tunnel tested hybrid UAV to develop high performance all terrain capable VTOL vehicles.

Optimization of RSW process parameters on tensile strength by taguchi method

S. Raja,K. Vignesh,M. Ravikumar,R. Sanjeevi 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

The aim of this research is to improve the Resistance Spot Welding (RSW) process characteristics of AISI SS316L joints ontensile shear load (TSL). The RSW process parameters like electrode diameter of 6mm to 8mm, welding current of 7 kA to9 kA, heating cycle periods of 7 to 9 are selected. The 2 mm sheet thickness has been selected for the welding trials and tensileshear test has been involved for all the trials for the purpose of identifying the TSL. Taguchi optimization technique is usedfor design the experiment with the help of Minitab software. It is observed that maximum TSL of 16 kN is observed by settingthe parameters at 6mm electrode diameter, 9 kA welding current and heating cycles of 9. The ANOVA table confirms thatwelding current majorly affects the quality of weld and all the trials are observed with interfacial failure.

Design, analysis and experimental investigation of a rotational piezoelectric energy harvester with storage system

Raja V,Umapathy Mangalanathan,Uma Gandhi,Praveen kumar B,Premkumar S 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

Energy harvesting from rotational motion has drawn attention over the years to energise low-power wireless sensor networks in a rotating environment. The harvester works efficiently in a small frequency range which has to be similar to the driving frequency. Because of the constraints of size, precision, and the energy harvester’s weight, it is challenging to design it to suit micro applications. To deal with this problem, this paper proposes a rotational piezoelectric energy harvester (RPEH), which generates a voltage output from rotational motion. This design increases the gravitational force acting on the system by increasing the length of the beam, which in turn increases its vibration in a transverse direction. EulerBernoulli’s theory is utilized to derive the mathematical model of the RPEH under rotational motion, and harvester dynamic equations are derived using the electromechanical Lagrange equations. A prototype of RPEH is developed and the exactness of the proposed mathematical model is verified using experimental results and numerical simulation. Maximum power of 43.77 µW is produced at a rotating frequency of 21 Hz (1260 rpm) with an optimum load resistance of 1141.3 kΩ.

Development of Superhydrophobic Microfibers for Bandage Coatings

T.S. Gokul Raja,K. Jeyasubramanian,M. Indhumathy 한국섬유공학회 2018 Fibers and polymers Vol.19 No.6

In this research work, a fabricated composite fiber is proposed to protect wound surfaces from infectious organisms present in water. The composite fiber comprising PMMA, ZnO, and zinc stearate was developed using an electrospinning technique. The fiber surface was scientifically studied using scanning electron microscope, Energy dispersive analysis of X-rays, powder X-ray diffraction analysis and Fourier transform Infra-Red analysis. The pores present in between perpendicularly aligned fibers serves as an excellent medium for vapor transport to a wound surface. The maximum water contact angle of the developed fiber surface was approximately 151 degrees. A commercial cotton bandage after coated with this composite layer behaves as a perfect barrier to the entry of infectious water towards the wound. The pores in the fiber surface support rich supply of environmental oxygen and transport of exudate vapor from the wound. This fiber when coated over a cotton bandage cloth on one side served as an excellent wound protecting bandage against the penetration of external microbial water and also it admits the air, water vapor etc., towards the interior. Water penetration ability of hydrophilic cotton bandage and the water arresting ability of superhydrophobic fiber coated bandage were evaluated using a facile technique. Furthermore, antimicrobial activity of test samples was evaluated against gram positive and gram negative microorganism. Also, a bacterial infiltration test supports the blocking capability of superhydrophobic fiber to water-borne bacteria. The results obtained through this experiment may be used in future as wound healing bandages in an efficient manner.

Precursor Events in Environmentally Assisted Cracking Behaviour of Light Metals

( V. S. Raja ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.4

Light metal alloys of Mg, Ti, and Al undergo environmentally assisted cracking (EAC). Passive film breakdown and pitting are not only precursor events for stress corrosion, but can accelerate hydrogen evolution that is responsible for hydrogen embrittlement. This is clearly demonstrated in the case of Mg and Ti alloys. The so-called innocuous precipitates, which do not directly participate in either alloy strengthening or EAC can be effective precursors for initiating EAC. This aspect is highlighted using high strength aluminium alloys. Such behaviours lead to a paradigm shift in the design of alloys with resistance to EAC.