http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Atul Thakre,Ajeet Kumar,Dae-Yong Jeong,Geon-Tae Hwang,Woon-Ha Yoon,Ho-Yong Lee,Jungho Ryu 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2
The solid solution of relaxor and lead titanate single crystals have been an excellent choice for electromechanical applicationssuch as energy harvesters, SONARs, transducers, and biomedical equipment. The mechanical quality factor ( Q m ) plays acrucial role in such applications using high power resonance condition. In this work, 32 mode (011) oriented along thicknessdirection, Generation-III piezoelectric single crystals based on PMN-PZT [71Pb(Mg 1/3 Nb 2/3 )O 3 –29PbZrTiO 3 ] havebeen grown by solid state single crystal growth method. The Mn doping concentration in the crystals were systematicallycontrolled within the range of 0 to 1.0 mol.%. The piezoelectric properties noticeably varied with the Mn doping concentrationwhen the content is over 0.1 mol.%. In order to obtain signifi cant enhancement in Q m in PMN-PZT single crystals,especially, the Mn doping concentration should be higher than 0.7 mol.% (which off ers highest fi gure of merit) for highpower resonance applications.
Kumar Ajeet,Lee Geon,Thakre Atul,Patil Deepak Rajaram,Han Guifang,Ryu Jungho 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.6
This study reports the fabrication of manganese (Mn) doped antiferroelectric (AFE) thick fi lms (thickness of ~ 2 μm) of (Pb0.93 La0.07 )(Zr0.82 Ti0.18 )O3 (PLZT 7/82/18) at room temperature using aerosol deposition (AD) technique without any additional thermal treatment. The Mn-doped PLZT 7/82/18 AD thick fi lms demonstrate excellent energy storage and electrical properties despite being fabricated at room temperature. The dielectric properties of the PLZT AD thick fi lms were investigated across a frequency range of 100 Hz–1 MHz and a temperature range of 25–250 o C. The Mn-doped PLZT AD thick fi lms exhibit a dielectric constant of ~ 108, low dielectric loss of 0.0211, and high-temperature stability of ~ 5.5% (from 1 kHz to 1 MHz). The bipolar P-E and I-E hysteresis loops of the PLZT AD thick fi lms do not show an AFE behavior, however, resemble the paraelectric/dielectric type of loops. The Mn-doped PLZT AD thick fi lms exhibit high dielectric breakdown strength (DBS) of ~ 5420 kV/cm, energy-storage density (ESD) of ~ 38.7 W/cm 3 , with high energy effi ciency of ~ 71%. Additionally, the Mn-doped PLZT AD thick fi lms demonstrate a low leakage current and excellent fatigue properties, as indicated by the obtained polarization, DBS, ESD, and energy effi ciency after 10 8 cycles.
Use of Computational Fluid Dynamics for the Design and Analysis of Gas Turbine Combustors
Niveditha Krishnamoorthy,Piyush Thakre,Yongzhe Zhang,Richard Clayton,Graham Goldin,Rajesh Rawat 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11
The use of computational fluid dynamics (CFD) for the design and analysis of the flow and combustion in gas turbine combustors is considered to be a cost effective alternative to time-consuming and expensive design of experiments studies. With stringent emission regulations being enforced for these combustion systems, efforts towards optimization of the combustor geometry, and its operating conditions to minimize fuel consumption, emissions, and cost are also being undertaken using CFD. Reacting flow modeling in gas turbine combustors is a multi-scale, multi-physics process which requires an adequate representation of the flow, chemistry, and heat transfer mechanisms taking place in these systems. The models/approximations used in simulating gas turbine combustors directly influence the predictive capability of the simulations. In this study, the commercial software STAR-CCM+ is used model all the processes taking place in a gas turbine combustor. STAR-CCM+ solves the Navier-Stokes equation using the finite volume formulation. The choice to represent the combustion chemistry via global reactions, tabulated methodology, or detailed kinetic modeling is available for premixed, non-premixed and partially premixed combustion regimes. The combustion model selection is typically driven by the intended purpose of the simulation. Radiative heat transfer is modeled using the discrete ordinates methodology. In order to study the mechanical durability of various components in these systems, a full conjugate heat transfer (CHT) analysis is also performed where, the liner and other solids are explicitly modeled in the fully-coupled simulation. In this investigation, both the Reynolds Averaged Simulation (RANS) methodology and the Large-Eddy Simulation (LES) methodology are explored and the results are summarized.
Ajeet Kumar,Jang Yuel Yoon,Atul Thakre,Mahesh Peddigari,정대용,Young-Min Kong,Jungho Ryu 한국세라믹학회 2019 한국세라믹학회지 Vol.56 No.4
In this study, the dielectric and polarization properties of manganese (Mn% = 0.0, 0.1, 0.2, 0.5) doped (Pb0.93La0.07)(Zr0.82Ti0.18)O3 (PLZT 7/82/18) anti-ferroelectric ceramics were studied for energy storage capacitor and pyroelectric applications. A systematic investigation demonstrated that the electric properties of PLZT 7/82/18 ceramics are affected significantly by the Mn-doping content. A maximum dielectric constant of ~ 2,128 at 1 kHz was found for 0.1% Mn-doped PLZT ceramics with a low dielectric loss of 0.018. The bipolar polarization versus electric field (P-E) hysteresis loops were traced for all compositions showing a typical anti-ferroelectric nature. The breakdown field was found to decrease with Mn-doping. The energy storage density and efficiency were found to be 460 J/cm3 and ~ 63%, respectively, for 0.2% Mn-doped PLZT ceramics. The pyroelectric coefficient of PLZT ceramics shows an increase based on the amount of Mn-doping.
Kumar, Ajeet,Yoon, Jang Yuel,Thakre, Atul,Peddigari, Mahesh,Jeong, Dae-Yong,Kong, Young-Min,Ryu, Jungho The Korean Ceramic Society 2019 한국세라믹학회지 Vol.56 No.4
In this study, the dielectric and polarization properties of manganese (Mn% = 0.0, 0.1, 0.2, 0.5) doped (Pb<sub>0.93</sub>La<sub>0.07</sub>)(Zr<sub>0.82</sub>Ti<sub>0.18</sub>)O<sub>3</sub> (PLZT 7/82/18) anti-ferroelectric ceramics were studied for energy storage capacitor and pyroelectric applications. A systematic investigation demonstrated that the electric properties of PLZT 7/82/18 ceramics are affected significantly by the Mn-doping content. A maximum dielectric constant of ~ 2,128 at 1 kHz was found for 0.1% Mn-doped PLZT ceramics with a low dielectric loss of 0.018. The bipolar polarization versus electric field (P-E) hysteresis loops were traced for all compositions showing a typical anti-ferroelectric nature. The breakdown field was found to decrease with Mn-doping. The energy storage density and efficiency were found to be 460 J/㎤ and ~ 63%, respectively, for 0.2% Mn-doped PLZT ceramics. The pyroelectric coefficient of PLZT ceramics shows an increase based on the amount of Mn-doping.
Tushar Krishnarao Mowade,Shankar Pandurang Dange,Mrunali Balkrushna Thakre,Vaibhav Deorao Kamble 대한치과보철학회 2012 The Journal of Advanced Prosthodontics Vol.4 No.1
PURPOSE: The aim of this in-vitro investigation was to describe the effect of reinforcement with different fibers on impact strength of heat polymerized polymethyl methacrylate (PMMA) denture base resin and to analyze the effect of surface treatment of the fibers on the impact strength. MATERIALS AND METHODS: The specimens were fabricated from the dies formed as per standard ASTM D4812. 2% by weight of glass, polyethylene and polypropylene fibers were incorporated in the PMMA resin. The Izod impact testing was performed on the unnotched specimens and the values obtained were analyzed using appropriate one way ANOVA, followed by unpaired t-test. Fractured ends of the samples were subjected to the SEM analysis. RESULTS: The polypropylene fibers with plasma treatment showed the highest impact strength (9.229 × 102 J/m) followed by the plasma treated polyethylene fibers (9.096 × 102 J/m), untreated polypropylene fibers (8.697 × 102 J/m), untreated polyethylene fibers (7.580 × 102 J/m), silane treated glass fibers (6.448 × 102 J/m) and untreated glass fibers (5.764 × 102 J/m). Also the surface treatment of all the fibers has shown the significant improvement in impact strength. Findings of the SEM analysis justified the improvement in impact strength after surface treatment. CONCLUSION: Reinforcement with the fiber is an effective method to increase the impact strength of PMMA denture base resin. The surface treatment of fibers further increases the impact strength significantly.
Raj K. Singh,Shubham Pandey,Rakesh C. Saxena,Gananath D. Thakre,Neeraj Atray,Siddharth S. Ray 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.26 No.-
Two additives CySBE-A and B were prepared via a two step synthesis. First, the cystine schiff base (CySB) was synthesized utilizing 3,5-di-t-butyl-4-hydroxybenzaldehyde. In the second step, its esterification with lauroyl alcohol and 2-ethyl hexanol results the final products CySBE-A and B respectively. Both additives were evaluated as multifunctional additive in polyol base oil for antioxidant, antifriction, antiwear and anticorrosion property. Universal oxidation test (IP-306) was used for evaluating antioxidant property. Antifriction and antiwear properties in terms of average friction coefficient and wear scar diameter (WSD) were evaluated using four ball test. The CySBE-A was found to be effective than CySBE-B.
Suryawanshi Hiralal M.,Borghate Vijay B.,Ramteke Manojkumar R.,Thakre Krishna L. The Korean Institute of Power Electronics 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.4
This paper deals with novel electronic ballast based on single-stage power processing topology using a symmetrical half-bridge inverter and current injection circuit. The half-bridge inverter drives the output parallel resonant circuit and injects current through the power factor correction (PFC) circuit. Because of high frequency current injection and high frequency modulated voltage, the proposed circuit maintains the unity power factor (UPF) with low THD even under wide variation in ac input voltage. This circuit needs minimum and lower sized components to achieve the UPF and high efficiency. This leads to an increase in reliability of ballast at low cost. Furthermore, to reduce cost, the electronic ballast is designed for two series-connected fluorescent lamps (FL). The analysis and experimental results are presented for ($2{\times}36$ Watt) fluorescent lamps operating at 50 kHz switching frequency and input line voltage (230 V, 50 Hz).
Hiralal M. Suryawanshi,Vijay B. Borghate,Manojkumar R. Ramteke,Krishna L. Thakre 전력전자학회 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.4
This paper deals with novel electronic ballast based on single-stage power processing topology using a symmetrical half-bridge inverter and current injection circuit. The half-bridge inverter drives the output parallel resonant circuit and injects current through the power factor correction (PFC) circuit. Because of high frequency current injection and high frequency modulated voltage, the proposed circuit maintains the unity power factor (UPF) with low THD even under wide variation in ac input voltage. This circuit needs minimum and lower sized components to achieve the UPF and high efficiency. This leads to an increase in reliability of ballast at low cost. Furthermore, to reduce cost, the electronic ballast is designed for two series-connected fluorescent lamps (FL). The analysis and experimental results are presented for (2 × 36 Watt) fluorescent lamps operating at 50 ㎑ switching frequency and input line voltage (230 V, 50 ㎐).