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Single Fully Differential Second Generation Current Conveyor Based Four-Quadrant Analog Multiplier Design and Its Applications

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Chinese Journal of Electronics 2020年第5期29卷 959-965页

作者： roy Suvajit PAL Radha-Raman Department of Physics and Technophysics Vidyasagar University

This manuscript presents a new fourquadrant analog multiplier using a recently reported current mode active building block, namely the Fully differential second generation current conveyor(FDCCⅡ).The proposed circuit employs single FDCCⅡ and two NMOSFETs only, thus has simple architecture. It is fully-integrable as no other external passive component has been used. Non-ideal behaviour of the reported configuration has been analysed considering current and voltage tracking errors of the FDCCⅡ. Workability of the derived multiplier is verified with PSPICE(Cadence16.6) simulations using model parameter of TSMC 0.35μm CMOS process and found to be in close agreement with theoretical anticipations. The static power consumption of the circuit is 0.107 mW. The circuit works well with good linearity(nonlinearity error ≤ 0.96%) for the input voltage range of ±0.5 V for a supply voltage of ±1 V and the output is insensitive to temperature variation. Simulation results show that the –3 dB bandwidth of the proposed multiplier is 20.67 MHz and the output referred noise√is less than 9 nV/Hz at 1 kΩ load condition. MonteCarlo analysis has also been performed for the proposed configuration. The applicability of the reported multiplier as amplitude modulator, squarer, and frequency doubler are also demonstrated.

关键词： Four-quadrant analog multiplier Fully differential second generation current conveyor (FDCCII) Amplitude modulator Squarer Frequency doubler

Geospatial characteristics of fire occurrences in southern hemispheric Africa and Madagascar during 2001-2020

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Journal of Forestry Research 2023年第2期34卷 553-563页

作者： Chuyan Wan Shouraseni Sen roy Department of Earth and Planetary Sciences Northwestern UniversityEvanstonILUSA Department of Geography and Sustainable Development University of MiamiCoral GablesFLUSA

For this study of long-term spatial patterns and trends of active fires in southern hemispheric Africa and on Madagascar from 2001 to 2020,active fire data from the MODIS FIRMS global fire data products were *** annual center of fire concentration tended to migrate toward the preserved rainforests and nature conservation areas in the Congo Basin and the mountain forests on the northeastern coast of *** frequency varied seasonally at both study *** used geo statistical analysis techniques,such as measures of dispersion and emerging hot spot analysis,to reveal long-term trends in spatial patterns of fire *** southern hemispheric Africa,the observed active fires tended to drift northward toward the Zambia-DRC border in the Congo *** northward migration progressed toward humid rainforests,which were better suited to sustaining repeated fire *** Madagascar,the observed active fires tended to migrate toward the east coast in protected mountain *** spatial patterns of long-term trends showed a concentration of fires in the tropical regions of southern hemispheric ***,smaller clusters of new hot spots were located over eastern South Africa,overlapping with undifferentiated *** Madagascar,both hot and cold spots were identified and were separated by the highland region in the center of the *** of the eastern island was characterized by cold spots that received less precipitation than did the rest of the *** presence of increasing hots spots in the densely vegetated areas highlights the urgent need for fire prevention and management in this region.

关键词： Emerging hot spots analysis FIRMS Forest fi res Madagascar MODIS Southern hemispheric Africa Wildfi res

Milky Way globular cluster dynamics:are they preferentially co-rotating?

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Research in Astronomy and Astrophysics 2020年第8期20卷 280-286页

作者： Saikat Das Nirupam roy Astronomy&Astrophysics Group Raman Research InstituteBangalore 560080India Department of Physics Indian Institute of ScienceBangalore 560012India

The motion of baryonic components of the Milky Way is governed by both luminous and dark matter content of the ***,the dynamics of Milky Way globular clusters(GCs)can be used as tracers to infer the mass model of the Galaxy up to a large *** this work,we apply the directly observable line-of-sight velocities to test if the dynamics of the GC population are consistent with an assumed axisymmetric gravitational potential of the Milky *** this,we numerically compute the phase space distribution of the GC population where the orbits are either oriented randomly or co-/counter-rotating with respect to the stellar *** we compare the observed position and line-of-sight velocity distribution of^150 GCs with those of the *** found that,for the adopted mass model,the co-rotating scenario is the favored model based on various statistical *** do the analysis with and without the GCs associated with the progenitors of early merger *** analysis can be extended in the near future to include precise and copious data to better constrain the Galactic potential up to a large radius.

关键词： Galaxy:kinematics and dynamics globular clusters:general galaxies:dwarf Galaxy:halo methods:statistical

Angiotensin-converting enzyme inhibitors from plants: A review of their diversity, modes of action, prospects, and concerns in the management of diabetes-centric complications

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Journal of Integrative Medicine 2021年第6期19卷 478-492页

作者： Rakhi Chakraborty Swarnendu roy Department of Botany A.P.C.Roy Government CollegeMatigara 734010West BengalIndia Plant Biochemistry Laboratory Department of BotanyUniversity of North BengalRaja Rammohunpur 734011West BengalIndia

Angiotensin-converting enzyme(ACE)inhibitors are antihypertensive medications often used in the treatment of diabetes-related *** ACE inhibitors are known to cause serious side effects like hypotension,renal insufficiency,and ***,there has been an intensifying search for natural ACE *** plants or plant-based extracts are known to possess ACEinhibitory *** this review,articles focusing on the natural ACE inhibitors extracted from plants were retrieved from databases like Google Scholar,Pub Med,Scopus,and Web of *** have found more than 50 plant species with ACE-inhibitory *** them,Angelica keiskei,Momordica charantia,Muntingia calabura,Prunus domestica,and Peperomia pellucida were the most potent,showing comparatively lower half-maximal inhibitory concentration *** the bioactive metabolites,peptides(e.g.,Tyr-Glu-Pro,Met-Arg-Trp,and Gln-Phe-Tyr-Ala-Val),phenolics(e.g.,cyanidin-3-Osambubioside and delphinidin-3-O-sambubioside),flavonoids([-]-epicatechin,astilbin,and eupatorin),terpenoids(ursolic acid and oleanolic acid)and alkaloids(berberine and harmaline)isolated from several plant and fungus species were found to possess significant ACE-inhibitory *** were also known to possess promising antioxidant,antidiabetic,antihyperlipidemic and anti-inflammatory *** the minimal side effects and lower toxicity of herbal compounds,development of antihypertensive drugs from these plant extracts or phytocompounds for the treatment of diabetesassociated complications is an important *** review,therefore,focuses on the ACE inhibitors extracted from different plant sources,their possible mechanisms of action,present status,and any safety concerns.

关键词： Angiotensin-converting enzyme Inhibitor Herbal medicine Hyperglycaemia Hypertension Bioactive metabolite

A Kenmotsu Metric as a *-conformal Yamabe Soliton with Torse Forming Potential Vector Field

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Acta Mathematica Sinica,English Series 2021年第12期37卷 1896-1908页

作者： Soumendu roy Arindam BHATTACHARYYA Department of Mathematics Jadavpur UniversityKolkata 700032India

The purpose of the present paper is to deliberate *-conformal Yamabe soliton,whose potential vector field is torse-forming on Kenmotsu ***,we have shown the nature of the soliton and find the scalar curvature when the manifold admitting *-conformal Yamabe soliton on Kenmotsu ***,we have evolved the characterization of the vector field when the manifold satisfies *-conformal Yamabe *** we have embellished some applications of vector field as torse-forming in terms of *-conformal Yamabe soliton on Kenmotsu *** have developed an example of *-conformal Yamabe soliton on 3-dimensional Kenmotsu manifold to prove our findings.

关键词： *-conformal Yamabe soliton torse forming vector field conformal Killing vector field Kenmotsu manifold

An approach towards estimating critical value of waiting time at transit stops

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第2期8卷 257-266页

作者： Subhojit roy Debasis Basu School of Infrastructure Indian Institute of Technology BhubaneswarOdisha 752050India

Waiting time at transit stops is found to be an influential policy variable for a passenger’s decision on whether to undertake a given transit service. With regard to policy framework for improvement of operational service headway of a transit service and thereby its waiting time, the necessity to have knowledge on its critical value becomes inevitable. The critical value of waiting time for passengers waiting at transit stops is that duration beyond which passengers are found to be no more interested to wait for a that transit service. The paper demonstrates an approach for estimating the critical value of waiting time at urban transit stops with reference to public transport services such as city bus and shared-auto operational in Bhubaneswar, India. The critical value of waiting time is estimated from the point on cumulative distribution curve of waiting time frequency distribution, at which the maximum rate of change of the slope of curve occurs. The work assumes two positively skewed distributions such as gamma and log-normal for observed distributional pattern of waiting time. The work identifies that gamma distribution is comparatively fitting the observed data better than log-normal distribution. The study reveals that the critical value of waiting time for city bus passengers is about twice than that of shared auto ***, the study presents new information on critical values of waiting time with reference to an urban area of a developing country, it also demonstrates an experience on application of probability distribution functions for understanding distributional pattern of waiting time.

关键词： Traffic engineering Waiting time at transit stop Critical value of waiting time Probability density function Gamma and log-normal distribution

Unexpected thermal conductivity enhancement in aperiodic superlattices discovered using active machine learning

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npj Computational Materials 2022年第1期8卷 99-105页

作者： Prabudhya roy Chowdhury Xiulin Ruan School of Mechanical Engineering and the Birck Nanotechnology Center Purdue UniversityWest LafayetteIN47907-2088USA

While machine learning(ML)has shown increasing effectiveness in optimizing materials properties under known physics,its application in discovering new physics remains challenging due to its interpolative *** this work,we demonstrate a general-purpose adaptive ML-accelerated search process that can discover unexpected lattice thermal conductivity(κ_(l))enhancement in aperiodic superlattices(SLs)as compared to periodic superlattices,with implications for thermal management of multilayer-based electronic *** use molecular dynamics simulations for high-fidelity calculations ofκ_(l),along with a convolutional neural network(CNN)which can rapidly predictκ_(l)for a large number of *** ensure accurate prediction for the target unknown SLs,we iteratively identify aperiodic SLs with structural features leading to locally enhanced thermal transport and include them as additional training data for the *** identified structures exhibit increased coherent phonon transport owing to the presence of closely spaced interfaces.

关键词： thermal conductivity transport

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中性粒子分析仪的研究现状

原子能科学技术 2024年第S2期58卷 501-511页

作者：林炜平马龙汪彦熹屈玉凡罗圆谢德豪王硕曲国峰任培培罗小兵刘星泉韩纪锋 roy WADA 臧临阁朱敬军四川大学原子核科学技术研究所辐射物理及技术教育部重点实验室四川成都610064 核工业西南物理研究院四川成都610218 Texas A&M University Texas USA 77843

中性粒子分析仪(NPA)作为托卡马克(Tokamak)装置的重要诊断工具,在等离子体物理研究中具有重要科学意义和广泛应用前景。NPA通过精确测量从等离子体中逃逸的中性粒子,可获取等离子体内部的关键信息,包括离子温度、快离子能谱分布和氢同... 详细信息

中性粒子分析仪(NPA)作为托卡马克(Tokamak)装置的重要诊断工具,在等离子体物理研究中具有重要科学意义和广泛应用前景。NPA通过精确测量从等离子体中逃逸的中性粒子,可获取等离子体内部的关键信息,包括离子温度、快离子能谱分布和氢同位素比例等。自20世纪60年代首台NPA问世以来,经过60余年的技术发展,其诊断能力已经实现了质的飞跃,并且发展出了多种类型的NPA。针对中国环流3号(HL-3)装置的快离子物理研究,四川大学与核工业西南物理研究院联合研制了基于LYSO+SiPM探测器的串联式平行电磁场结构的NPA(E//B NPA)。该E//B NPA已安装到HL-3装置,并在等离子体放电实验中成功测量到高能量氘(D)中性粒子能谱,为今后HL-3装置中性粒子诊断及快离子研究奠定了坚实的技术基础。

关键词：中性粒子分析仪能量和质量分辨托卡马克快离子物理

Parametric computational study on butterfly-shaped hysteretic dampers

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Frontiers of Structural and Civil Engineering 2019年第5期13卷 1214-1226页

作者： Alireza FARZAMPOUR Matthew roy EATHERTON Department of Civil and Environmental Engineering Virginia TechBlacksburgVA 24060USA

A parametric computational study is conducted to investigate the shear yielding, flexural yielding, and lateral torsional buckling limit states for butterfly-shaped links. After validating the accuracy of the finite element modeling approach against previous experiments, 112 computational models with different geometrical properties were constructed and analyzed including consideration of initial imperfections. The resulting yielding moment, corresponding critical shear force, the accumulation of plastic strains through the length of links as well as the amount of energy dissipated are investigated. The results indicate that as the shape of the butterfly-shaped links become too straight or conversely too narrow in the middle, peak accumulated plastic strains increase. The significant effect of plate thickness on the buckling limit state is examined in this study. Results show that overstrength for these links (peak force divided by yield force) is between 1.2 and 4.5, with straight links producing larger overstrength. Additionally, proportioning the links to delay buckling, and designing the links to yield in the flexural mode are shown to improve energy dissipation.

关键词： structural fuse hystcretic damper finite element analysis energy dissipation initial imperfection butterfly-shaped links