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Fabrication and characterization of a GaN/(4H)SiC vertical pn power diode using direct and interfaced epitaxial-growth approaches

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Journal of Semiconductors 2013年第4期34卷 20-23页

作者： bose Srikanta Mazumder S K Laboratory for Energy and Switching-Electronics Systems Department of Electrical and Computer EngineeringUniversity of Illinois at ChicagoChicagoIL:60607USA

We report the fabrication and characterization of a vertical pn power diode which is realized using two separate epitaxial-growth mechanisms：（a） p-GaN over p-（4H）SiC, and （b） p-GaN over n-（4H）SiC with A1N as the interface layer. In all of the cases, n＋-doped （4H）SiC serves as the cathode substrate. Pd（200 A）/Au（10000 A） is used for the anode contact while Ni（1000A） is used for the bottom cathode contact. The measured forward drop of the pn diode with A1N as the interface material is found to be around 5.1 V; whereas, it is 3 V for the other sample structure. The measured reverse-blocking voltage is found to be greater than 200 V.

关键词： GaN (4H)SiC vertical pn power diode power electronics

Corrosion behavior of 2024 Al-Cu-Mg alloy of various tempers

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Transactions of Nonferrous Metals Society of China 2013年第11期23卷 3215-3227页

作者： K.S.GHOSH Md.HILAL Sagnik bose Department of Metallurgical and Materials Engineering National Institute of TechnologyDurgapur-713 209 India

Corrosion behavior of 2024 Al-Cu-Mg alloy of different tempers was assessed by potentiodynamic polarization studies in 3.5% NaCl solution, 3.5% NaCI＋I.0% H2O2 solution and 3.5% NaCl solution at pH 12. Polarization curves showed shifting of corrosion potential （φPcor） towards more negative potential with increasing ageing time and shifting of φcorr in the positive direction with the addition of H2O2 in NaCl solution. Polarization curves in 3.5% NaCl solution at pH 12 exhibited distinct passivity phenomenon. Optical micrographs of the corroded surfaces showed general corrosion, extensive pitting and intergranular corrosion as well. Cyclic potentiodynamic polarization curves exhibited wide hysteresis loop and the mode of corrosion attack confirmed that the alloy states are susceptible to pit growth damage. Attempts were made to explain the observed corrosion behavior of the alloy of various tempers in different electrolytes with the help of microstructural features.

关键词： 2024 Al-Cu-Mg alloy ageing behavior electrochemical polarization passivity pitting potential

Eco-Friendly Phyto-Synthesis of Silver Nanoparticles Using Jatropha Seedcake Extract

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Chinese Physics Letters 2013年第12期30卷 165-169页

作者： Anjali bose Haresh Keharia M.P.Deshpande BRD School of Biosciences Sardar Patel MaidanVadtal RoadP.O.Box 39Satellite CampusSardar Patel UniversityVallabh Vidyanagar 388120GujaratIndia Department of Physics Sardar Patel UniversityVallabh Vidyanagar 388120GujaratIndia

Phytosynthesis of metal nanoparticles is gaining importance due to their biocompatibility,low toxicity and eco-friendly *** the present study,an aqueous extract of Jatropha seedcake(JSC)is assessed as a reducing and stabilizing agent for the synthesis of silver nanoparticles(AgNPs).The maximum reduction of silver ions occur when 1 mM AgNO_(3) solution is treated with 0.1 volume fraction of JSC extract in boiling water bath for 10 *** synthesis of AgNPs is monitored by the excitation of surface plasmon resonance using UV-vis *** AgNPs are found to be mono-dispersed,spherical with average particle size of 10.48±74 nm when analyzed by transmission electron *** selected area electron diffraction(SAED)ring pattern indicated the polycrystalline nature of the *** x-ray diffraction data further confirm the presence of characteristic(111),(200),(220),(311)and(222)diffraction planes of face centered cubic structure,and the calculated lattice parameter comes out to be 4.083Å.FTIR analysis reveals the involvement of proteins and phenols in reduction and stabilization of *** synthesized AgNPs have significant antibacterial action on both the Gram positive and negative bacteria.

关键词： silver synthesis stabilization

Structural and Operational Optimization of A Flapping Fin Used as A Self-Propulsor for AUV Propulsion

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China Ocean Engineering 2022年第1期36卷 86-99页

作者： FAN Shuang-shuang CI Xiao-han Neil bose CHENG Xiao School of Marine Sciences Sun Yat-sen UniversityZhuhai 519082China Southern Laboratory of Ocean Science and Engineering Zhuhai 519000China Department of Ocean and Naval Architectural Engineering Memorial University of NewfoundlandSt.John’sNL A1C 5S7Canada School of Geospatial Engineering and Science Sun Yat-sen UniversityZhuhai 519082China

Marine mammals could directly harvest energy from waves and obtain propulsive force through oscillating flapping fins or horizontal tail flukes,which in many cases have been observed and proved to be *** propulsion generated by the flapping fin has been analyzed by many researchers from both the theoretical and experimental prospects;however,the structural and operational optimization of a flapping fin for the optimal propulsion performance has been less studied,such as the investigation of the effects of the phase difference between heave and pitch motion,maximum oscillation angle,fin shape,oscillation centre of the fin and the operating sea state on the generated *** this paper,the flapping fin is used as a self-propulsor to propel an autonomous underwater vehicle(AUV)for propulsion *** the optimization design of the flapping fin,its propulsion effect is numerically investigated with different structural parameters and under various operation conditions using computational fluid dynamics(CFD)*** and validation study have been implemented to quantify the numerical uncertainties and evaluate the accuracy of the proposed CFD ***,a series of case studies are thoroughly conducted to investigate the effects of different structural parameters and operational conditions on the generated propulsion of a flapping fin by CFD *** simulation results demonstrate that different structural parameters and operation conditions would significantly impact the magnitude and distribution state of the fluid pressure around the flapping fin surface,thus,affect the propulsion performance of the *** findings in this study will provide guidelines for the structural and operational optimization design of a flapping fin for self-propulsion of mobile platforms.

关键词： autonomous underwater vehicle(AUV) flapping fin self-propulsion computational fluid dynamics(CFD) optimization design

Suspended load in flows on erodible bed

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International Journal of Sediment Research 2009年第3期24卷 315-324页

作者： Sujit K. bose Subhasish DEY Visiting Fellow Department of Civil Engineering Indian Institute of Technology Chair Prof. Department of Civil Engineering Indian Institute of Technology

Steady state suspended-load of sediment transported in flow over erodible beds usually is treated by the advection-diffusion approach, though in recent years, it is being treated as a two-phase flow phenomenon incorporating kinetics of sediment particles. Among the advection-diffusion approaches, Rouse’s equation is the well-known, although a number of researchers in later periods have attempted to improve it by modifying the mixing length concept taking into account other aspects. In this paper, the advection-diffusion approach and associated logarithmic law of flow velocity are revisited. It is concluded from the logarithmic law that the Reynolds shear stress is a linear function of height above the bed, which reduces to bed shear stress in the case of a long horizontal channel. As a consequence, it is shown that the volumetric concentration of sediment is best approximated by the sum of two power laws of height above the bed. An equation is derived for the suspended-load transport rate in terms of elementary functions.

关键词： Sediment transport Fluvial hydraulics Suspended load Open channel flow

Properties of boron doped ZnO films prepared by reactive sputtering method: Application to amorphous silicon thin film solar cells

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Journal of Materials Science & Technology 2020年第20期52卷 136-143页

作者： Sukanta bose Sourav Mandal Asok K.Barua Sumita Mukhopadhyay Centre of Excellence for Green Energy and Sensor Systems Indian Institute of Engineering Science and TechnologyShibpurHowrah 711103West BengalIndia Centre for Energy Studies Indian Institute of Technology DelhiNew Delhi 110016India

Reactive sputtered boron-doped zinc oxide(BZO) film was deposited from argon,hydrogen and boron gas *** reactive sputtering technique provides us the flexibility of changing the boron concentration in the produced films by using the same intrinsic zinc oxide *** surface was obtained in the as-deposited *** surface morphology and the opto-electronic properties of the films can be controlled by simply varying the gas concentration *** varying the gas concentration ratio,the best obtained resistivity ~6.51×10^-4Ω-cm,mobility ~19.05 cm^2 V^-1 s^-1 and sheet resistance ~7.23Ω/□ were *** lower wavelength of light,the response of the deposited films improves with the increase of boron in the gas mixture and the overall transmission in the wavelength region 350-1100 nm of all the films are>85 %.We also fabricated amorphous silicon(a-Si) thin film solar cell on the best obtained BZO *** overall efficiency of the a-Si solar cell is 8.14 %,found on optimized BZO layer.

关键词： Magnetron reactive sputtering BZO Amorphous silicon Solar cells Zinc oxide(ZnO)

A Novel Framework for DDoS Attacks Detection Using Hybrid LSTM Techniques

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Computer Systems Science & Engineering 2023年第6期45卷 2553-2567页

作者： Anitha Thangasamy bose Sundan Logeswari Govindaraj Department of Computer Science and Engineering College of Engineering GuindyAnna UniversityChennai-600025TamilndauIndia

The recent development of cloud computing offers various services on demand for organization and individual users,such as storage,shared computing space,networking,*** Cloud Computing provides various advantages for users,it remains vulnerable to many types of attacks that attract cyber *** Denial of Service(DDoS)is the most common type of attack on cloud ***,Cloud computing professionals and security experts have focused on the growth of preventive processes towards DDoS *** DDoS attacks have become increasingly widespread,it becomes difficult for some DDoS attack methods based on individual network flow features to distinguish various types of DDoS ***,the monitoring pattern of traffic changes and accurate detection of DDoS attacks are most important and *** this research work,DDoS attack detection methods based on deep belief network feature extraction and Hybrid Long Short-Term Memory(LSTM)model have been proposed with NSL-KDD *** Hybrid LSTM method,the Particle Swarm Optimization(PSO)technique,which is combined to optimize the weights of the LSTM neural network,reduces the prediction *** deep belief network method is used to extract the features of IP packets,and it identifies DDoS attacks based on PSO-LSTM ***,it accurately predicts normal network traffic and detects anomalies resulting from DDoS *** proposed PSO-LSTM architecture outperforms the classification techniques including standard Support Vector Machine(SVM)and LSTM in terms of attack detection performance along with the results of the measurement of accuracy,recall,f-measure,precision.

关键词： Cloud computing distributed denial of service particle swarm optimization long short-term memory attack detection

Environmental impact improvements due to introducing automation into underground copper mines

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International Journal of Mining Science and Technology 2021年第6期31卷 1159-1167页

作者： Kyle Moreau Corey Laamanen Ron bose Helen Shang John Ashley Scott School of Engineering Laurentian UniversitySudburyON P3E 2C6Canada XPS–Glencore Greater SudburyON P0M 1S0Canada

A life-cycle assessment(LCA) model was developed to comparatively analyze the use of manual and automated mining equipment in underground copper mine *** and key variables that were determined to contribute to the environmental impact of operations were identified for six mine sites in a range of geographical locations around the *** model successfully calculated carbon dioxide(CO_(2) eq.) emissions to within 4.9% of the reported annual emissions from the site's respective *** implementation of automation was found to decrease global warming potential by a range of 11.4%-18.0% or 3.9-17.9 kg CO_(2) eq./t *** model was also used to estimate the average reductions across several impact potentials including,acidification(11.9%-17.8%),eutrophication(7.6%-13.7%),and human toxicity(16.0%-20.0%).World-wide the mining industry is moving toward introducing significantly more automation to enhance productivity and *** novel work demonstrates an important third dimension that can support this move,reduced environmental impact.

关键词： Automation Underground copper mines Environmental improvements Life cycle assessment Modelling

In vitro and in vivo degradability,biocompatibility and antimicrobial characteristics of Cu added iron-manganese alloy

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Journal of Materials Science & Technology 2021年第25期84卷 159-172页

作者： Santanu Mandal Vijay Kishore Madhuparna bose Samit Kumar Nandi Mangal Ro Department of Metallurgical and Materials Engineering Indian Institute of Technology-KharagpurKharagpur 721302India Department of Veterinary Surgery&Radiology West Bengal University of Animal&Fishery SciencesKolkata 700037India Department of Biotechnology Indian Institute of TechnologyKharagpur 721302India

In recent years,iron(Fe)based degradable metal is explored as an alternative to permanent fracture fixation *** the present work,copper(Cu)is added in Fe-Mn system to enhance the degradation rate and antimicrobial ***-Mn-x Cu(x=0.9,5 and 10 wt.%)alloys are prepared by the meltingcasting-forging *** analysis confirms austenite phase stabilization due to the presence of Mn and *** predicted by Thermo-Calc calculations,Cu rich phase precipitations are noticed along the austenite grain *** behaviours of Cu added Fe-Mn alloys are investigated through static immersion and electrochemical polarization where enhanced degradation is found for higher Cu added *** challenged against *** bacteria,the Fe-Mn-Cu alloy media extract shows a significant bactericidal effect compare to the base *** vitro cytocompatibility studies,as determined using MG63 and MC3T3-E1 cell lines,indicate increased cell density as a function of time for all the *** implanted in rabbit femur,the newly developed alloy does not show any kind of tissue necrosis around the *** osteogenesis and higher new bone formation are observed with Fe-Mn-10 Cu alloy as evident from micro-computed tomography(μ-CT)and fluorochrome labelling.

关键词： Iron-manganese alloy Degradable metal In vitro Micro-CT