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Analysis of the electrical characteristics of GaInP/GaAs HBTs including the recombination effect

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Journal of Semiconductors 2012年第5期33卷 38-43页

作者： Gourab Dutta Sukla basu Indian Institute of Technology kharagpur ECE Department Kalyani Government Engineering College

An analytical model is used to predict the effects of surface recombination current on the gain and transit time of GalnP/GaAs heterojunction bipolar transistors（HBTs）.The present analysis shows that consideration of the recombination current gives current gain values that are comparable to those of the experimental *** dependence of current gain on temperature,base doping and emitter area are also analyzed,and the variation in collector current with emitter-base voltage,temperature and doping is considered.

关键词： GaInP/GaAs HBT current gain transit time recombination current surface recombination ideality factor

The evolution of graphene-based electronic devices

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International Journal of Smart and Nano Materials 2010年第3期1卷 201-223页

作者： Joydeep basu Jayanta.k.mar basu Tarun kanti Bhattacharyya Department of Electronics and Electrical Communication Engineering Department of Chemical Engineering Indian Institute of TechnologyKharagpur 721302India

Successful isolation of single-layer graphene,the two-dimensional allotrope of carbon from graphite,has fuelled a lot of interest in exploring the feasibility of using it for fabrication of various electronic devices,particularly because of its exceptional electronic *** is poised to save Moore’s law by acting as a successor of silicon-based *** article reviews the success story of this allotrope with a focus on the structure,properties and preparation of graphene as well as its various device applications.

关键词： electronic device FET field effect graphene nanoelectronics

Output only modal identification and structural damage detection using time frequency & wavelet techniques

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Earthquake Engineering and Engineering Vibration 2009年第4期8卷 583-605页

作者： S.Nagarajaiah B.basu Dept.of Civil & Environmental Eng.and Dept.of Mechanical Eng.& Material Sc. Rice University Dept.of Civil Structural& Environmental Eng.Trinity College Dublin

The primary objective of this paper is to develop output only modal identification and structural damage detection. Identification of multi-degree of freedom （MDOF） linear time invariant （LTI） and linear time variant （LTV--due to damage） systems based on Time-frequency （TF） techniques--such as short-time Fourier transform （STFT）, empirical mode decomposition （EMD）, and wavelets--is proposed. STFT, EMD, and wavelet methods developed to date are reviewed in detail. In addition a Hilbert transform （HT） approach to determine frequency and damping is also presented. In this paper, STFT, EMD, HT and wavelet techniques are developed for decomposition of free vibration response of MDOF systems into their modal components. Once the modal components are obtained, each one is processed using Hilbert transform to obtain the modal frequency and damping ratios. In addition, the ratio of modal components at different degrees of freedom facilitate determination of mode shape. In cases with output only modal identification using ambient/random response, the random decrement technique is used to obtain free vibration response. The advantage of TF techniques is that they arc signal based; hence, can be used for output only modal identification. A three degree of freedom 1：10 scale model test structure is used to validate the proposed output only modal identification techniques based on STFT, EMD, HT, wavelets. Both measured free vibration and forced vibration （white noise） response are considered. The secondary objective of this paper is to show the relative ease with which the TF techniques can be used for modal identification and their potential for real world applications where output only identification is essential. Recorded ambient vibration data processed using techniques such as the random decrement technique can be used to obtain the free vibration response, so that further processing using TF based modal identification can be performed.

关键词： Time-frequency methods short time Fourier transform Hilbert transform wavelets modal identification:output only structural health monitoring damage detection

Fabrication of core-shell PLGA/PLA-pNIPAM nanocomposites for improved entrapment and release kinetics of antihypertensive drugs

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Particuology 2018年第5期16卷 169-176页

作者： Tanushree basu Bonamali Pal Satnam Singh School of Chemistry and Biochemistry Thapar lnstitute of Engineering and TechnologyPatiala 147004Punjablndia

Polylactic acid (PLA)and poly(lactic-co-glycolic)acid (PLGA)are two commonly applied biodegrad- able polymers for the preparation of nanocomposites used in drug-delivery ***,these polymers la.k.desirable attributes such as resistance to aggregation during long-term storage due to *** improve their efficacy,in this work,PLA and PLGA were encapsulated within a shell of poly(N-isopropylacrylamide)(pNIPAM)using a single emulsion technique followed by an aqueous free radical precipitation polymerisation process,yielding core-shell PLA/PLGA-pNIPAM nanocomposites. The nanocomposites were cbaracterised using zeta potential,dynamic light scattering,and transmission electron microscopy analyses and were further applied as a delivery system for ramipril,an antihypertensive *** drug-loaded PLGA-pNIPAM core-shell nanoparticles exhibited a higher drug content (91%)and entrapment efficiency (78%)than their PLA *** in vitro release study of the formulations at pH 7.3in phosphate-buffered saline indicated that PLGA was more efficient than PLA with a sustained release of 86% of ramipril from the polymer matrix within ***,to determine the release kinetics,the data were fitted to korsmeyer-Peppas and Higuchi models;the release of ramipril from the polymer matrix followed zero-order rate kinetics and an anomalous (non-Fickian)diffusion mechanism.

关键词： Poly(lactic-co-glycolic)acid Polylactic acid Poly(N-isopropylacrylamide) Antihypertensive drug Entrapment efficiency Drug release

A time-domain nonlinear effective-stress non-Masing approach of ground response analysis of Guwahati city, India

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 61-75页

作者： Devdeep basu Madhulatha Boga Arindam Dey Department of Civil Engineering Indian Institute of Technology Guwahati

The response of subsoil strata subjected to seismic excitations plays an important role in governing the response of the overlying superstructures at any site. Ground response analysis(GRA) helps to assess the influence of soil characteristics on the propagating seismic stress waves from the bedrock level to the ground surface during an earthquake. For the northeastern region of India, located in the highest seismic zone in the country, conducting an extensive GRA study is of prime importance. Conventionally, most of the GRA studies are carried out using the equivalent linear method, which, being a simplistic approach, cannot capture the nonlinear behavior of soil during seismic shaking. This paper presents the outcomes of a one-dimensional effective stress based nonlinear GRA conducted for Guwahati city(located in northeast India) incorporating the non-Masing load/unload/reload characteristics. The various ground response parameters evaluated from this study help in assessing the ground shaking, soil amplification, and site responses expected in this region. 2D contour maps, which are representative of the distribution of some of these parameters throughout Guwahati city, are also developed. The results presented herein can serve as guidelines for the design of foundations and superstructures in this region.

关键词： ground response analysis nonlinear effective stress approach non-masing criteria ground response parameters soil amplification

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对印度经济增速放缓的忧思

中国改革 2024年第3期 90-93页

作者：考希克·巴苏不详

如果印度通过政策来促进短期增长,同时也为长期表现打下基础,信心自然就会上升。一旦投资回升,印度就能够恢复过去的快速增长,并在未来几年保持这种增长。

关键词：经济增速放缓印度快速增长

Application of fractal theory in assessing soil aggregates in Indian tropical ecosystems

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Journal of Forestry Research 2012年第3期23卷 355-364页

作者： S.k.Tripathi C.P.kushwaha S.k.basu Computer Science Department Banaras Hindu UniversityVaranasi-221005India Department of Forestry Mizoram UniversityAi-zawl-796009India Centre for Env.Sci.&Tech. Banaras Hindu UniversityVaranasi-221005India

Soil aggregation varies according to climatic and manage- ment factors, and is difficult to measure because of irregular shapes and sizes of soil aggregates. We applied fractal theory to assess soil aggrega- tion as affected by （1） land use change from forest to savanna, （2） nutri- ent additions in forest, ecotone, and savanna ecosystems, and （3） tillage practice and residue treatments in an agro-ecosystem. We used fractal dimensions nonlinear （D,o,-lin） and linear （Dlin） based on number of ag- gregates （N） and mass of aggregates （M）（the range of values were 2.6-2.89 and 2.694.41, respectively） to capture the variations in the sizes of soil aggregates due to land use and treatments/management in these ecosystems. The variation in the values of non-linear fractal dimension based on mass （DMnon-lin） was smaller in forest and savanna ecosystems with and without nutrient additions, while the variation was wider in agro-ecosystems with different management practices. Linear fractal dimensions based on number （Dr^i,） and mass （DMlin） of aggregates var- ied marginally in these ecosystems and did not capture the variations in soil aggregates well. The variations in non-linear fractal dimension indi- cate that continued nitrogen loading in forest accelerates the formation of macro-aggregates, whereas in savanna the situation was reversed. The values of non-linear fractal dimensions did not show significant change after 6 years of nutrient additions in the ecotone; reflecting a buffering mechanism of this system in soil aggregate formation. On the basis of non-linear fractal dimension values, we conclude that residue retention and minimum tillage are appropriate for proper maintenance of soil ag- gregate stability for sustained crop production in the Indian dry land agro-ecosystems

关键词： soil aggregates fractal tillage practice ecosystem Indian dry tropics

Broadband, High Gain, Narrow Width Rectangular Dielectric Resonator Antenna with Air Gap

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Journal of Electronic Science and Technology 2019年第1期17卷 90-96页

作者： a.k.t kumar Roy Sukla basu kalyani Government Engineering College

The broadband, narrow width, rectangular dielectric resonator antenna(RDRA) of aluminum nitride(εr=8.6) was designed and the effect of inclusion of air gap at the bottom of the dielectric resonator antenna(DRA),above the ground plane, was investigated. Gain around 7 dBi was obtained for DRA with air gap(DRAAG) over a broad bandwidth in upper X, ku, and k bands. Further enhancement in gain could be obtained by placing a metal wall parallel to the length of DRA. However, due to the presence of metal wall, bandwidth was reduced. These structures with the metal wall are capable of operating over a wide band extending from ku band to lower k band with the gain of around 10 dBi. CST Microwave Studio Software was used to simulate all these *** parameters of DRA with air gap were compared with several broadband DRA structures reported in recent literature. The proposed DRAAG with the metal wall in this paper is capable of operating over a wide bandwidth along with a significant gain.

关键词： Dielectric resonator antenna(DRA) rectangular dielectric resonator antenna(RDRA) wide band dielectric resonator antenna X ku and k bands dielectric resonator antenna

Transition metal-based single-atom catalysts(TM-SACs);rising materials for electrochemical CO_(2) reduction

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Journal of Energy Chemistry 2022年第7期31卷 444-471,I0012页

作者： Bishnupad Mohanty Suddhasatwa basu Bikash kumar Jena Materials Chemistry Department CSIR-Institute of Minerals and Materials TechnologyBhubaneswar 751013India Academy of Scientific&Innovative Research(AcSIR) Ghaziabad 201002India

The continuous increase of global atmospheric CO_(2) concentrations brutally damages our environment. A series of methods have been developed to convert CO_(2) to valuable fuels and value-added chemicals to maintain the equilibrium of carbon cycles. The electrochemical CO_(2) reduction reaction(CO_(2)RR) is one of the promising methods to produce fuels and chemicals, and it could offer sustainable paths to decrease carbon intensity and support renewable energy. Thus, significant research efforts and highly efficient catalysts are essential for converting CO_(2) into other valuable chemicals and fuels. Transition metal-based single atoms catalysts(TM-SACs) have recently received much attention and offer outstanding electrochemical applications with high activity and selectivity opportunities. By taking advantage of both heterogeneous and homogeneous catalysts, TM-SACs are the new rising star for electrochemical conversion of CO_(2) to the value-added product with high selectivity. In recent years, enormous research effort has been made to synthesize different TM-SACs with different M–Nxsites and study the electrochemical conversion of CO_(2) to CO. This review has discussed the development and characterization of different TMSACs with various catalytic sites, fundamental understanding of the electrochemical process in CO_(2) RR,intrinsic catalytic activity, and molecular strategics of SACs responsible for CO_(2)RR. Furthermore, we extensively review previous studies on 1 st-row transition metals TM-SACs(Ni, Co, Fe, Cu, Zn, Sn) and dual-atom catalysts(DACs) utilized for electrochemical CO_(2) conversions and highlight the opportunities and challenges.

关键词： CO_(2)RR Single-atom catalyst SACs Dual-atom catalyst DACs Transition metals Support catalysts