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Chinese Physics Letters 2013年第1期30卷 122-126页

作者： M.K.Mishra A.Phukan M.chakraborty Department of Physics Baosi Banikanta Kakati CollegeNagaonBarpetaAssam-781311India Department of Physics Madhabdev CollegeNarayanpurLakhimpurAssam-784164India Centre of Plasma Physics-Institute for Plasma Research TepesiaSonapurAssam-782402India

The influence of discharge voltage on ion collecting surfaces in the form of a metal plate and a mesh grid is investigated in a multi-dipole *** the experiment,a solid metal plate and a mesh grid are placed alternately at one end of the multi-dipole *** is seen that except for high negative bias,the ion space charge layer in front of the grid gets depleted with the increase in discharge voltage whereas it gets thickened in front of the *** is also observed that the electron loss at the cusp(anode current)changes accordingly in both the *** increase in discharge voltage can enhance the Bohm speed of ions towards the ion collecting ***,the negative potential applied to the ion collecting surfaces lowers the bulk plasma potential,which in turn affects the anode current.

关键词： dipole anode thick

A Novel Green IoT-Based Pay-As-You-Go Smart Parking System

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Computers, Materials & Continua 2021年第6期67卷 3523-3544页

作者： Andrea Sant Lalit Garg Peter Xuereb Chinmay chakraborty Faculty of Information&Communication Technology University of MaltaMsidaMalta Birla Institute of Technology MesraJharkhand814142India

The better management of resources and the potential improvement in trafc congestion via reducing the orbiting time for parking spaces is crucial in a smart city,particularly those with an uneven correlation between the increase in vehicles and *** paper proposes and analyses a novel green IoT-based Pay-As-You-Go(PAYG)smart parking system by utilizing unused garage parking *** article also presents an intelligent system that offers the most favorable prices to its users by matching private garages’pricing portfolio with a garage’s current ***,the world’s fourth-most densely populated country,is considered as a case of a smart city for the implementation of the proposed *** results obtained conrm that apart from having a high potential system in such countries,the pricing generated correctly forecasts the demand for a particular garage at a specic time of the day and *** proposed PAYG smart parking system can effectively contribute to the macro solution to trafc congestion by encouraging potential users to use the system’s services and reducing the orbiting time for parking.

关键词： Smart parking garages smart city internet of things trafc congestion green IT

Compositional analysis in the nano-regime: A SIMS perspe ctive

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原子与分子物理学报 2005年第3期22卷 393-399页

作者： Subhendu Sarkar Purushottam chakraborty Surface Physics Division Saha Institute of Nuclear Physics 1/AF Bidhannagar Kolkata 700 064IndiaSurface Physics Division Saha Institute of Nuclear Physics 1/AF Bidhannagar Kolkata 700 064India

A serious problem in secondary ion mass spectrometry (SI MS ) analysis is its “matrix effect” that hinders the quantification of a certain species in a sample and consequently, appropriate corrective measures are taken to calibrate the secondary ion currents into respective concentrations for accu rate compositional analysis. Use of “calibration standards” is necessary for t his purpose. Detection of molecular MCs_n+ ions (M-element to be analyz ed , n=1, 2, 3,….) under Cs+ ion bombardment is a possible mean to minimiz e such matrix effect, enabling one to quantify without the need of calibration sta ndards. Our recent studies on MCs_n+ molecular ions aim towards the understanding of their formation mechanisms, which are important to know their e ffects on SIMS quantification. In-depth quantitative analysis is a major strength of SIMS for which ‘depth resolution’ is of significant relevance. The optimal choice of the impact pa rameters during SIMS analyses can play an effective role in obtaining data with ultra-high depth resolution. SIMS is possible at depth resolution in the nm or even sub-nm rang e, with quantifiable data obtained from the top monolayer onwards into the material. Wi th optimized experimental conditions, like extremely low beam current (down to ～10 nA), and low bombarding energy (below 1 keV), ultra-high depth resolution SIMS has e nabled interfacial composition analysis of ultra-thin films, quantum wells, heterostru ctures, etc. and complex low-dimensional structures with high precision and re peatability.

关键词： SIMS 次级离子质谱离子光谱测定法

Layered double hydroxide using hydrothermal treatment： morphology evolution, intercalation and release kinetics of diclofenac sodium

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Frontiers of Materials Science 2017年第4期11卷 395-409页

作者： Mathew JOY SrividhyaJ. IYENGAR Jui chakraborty Swapankumar GHOSH Project Management Division CSIR-Central Glass & Ceramic Research Institute Kolkata-700032 India Bioceramics & Coating Division CSIR-Central Glass & Ceramic Research Institute Kolkata-700032 India

The present work demonstrates the possibilities of hydrothermal trans- formation of Zn-AI layered double hydroxide （LDH） nanostructure by varying the synthetic conditions. The manipulation in washing step before hydrothermal treatment allows control over crystal morphologies, size and stability of their aqueous solutions. We examined the crystal growth process in the presence and the absence of extra ions during hydrothermal treatment and its dependence on the drug （diclofenac sodium （Dic- Na）） loading and release processes. Hexagonal plate-like crystals show sustained release with -90% of the drug from the matrix in a week, suggesting the applicability of LDH nanohybrids in sustained drug delivery systems. The fits to the release kinetics data indicated the drug release as a diffusion-controlled release process. LDH with rod-like morphology shows excellent colloidal stability in aqueous suspension, as studied by photon correlation spectroscopy.

关键词： layered double hydroxide crystal morphology hydrothermal treatment drug loading

Spatial organization of multiple plant species in arid ecosystems:linking patterns and processes

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Journal of Arid Land 2010年第1期2卷 9-13页

作者： Amit chakraborty B.Larry LI Ecological Complexity and Modeling Laboratory Department of Botany and Plant SciencesUniversity of California Center for Conservation Biology University of California XIEG-UCR International Center for Arid Land Ecology University of California

Spatial organization of multiple plant species that appears as a non-random distribution of vegetative patches is one of the mostly observed spatial patterns in arid ecosystems. Yet understanding of ecological processes allowing this spatial pattern to emerge through interspecific interactions is still lacking. With a proposed conceptual model involving interspecific trade-offs between species competitive ability and colonization ability, we have argued that within patch abundance dynamics regulated by the mechanisms of competition are strongly influenced by the between patches colonization dynamics that are maintained via this trade-offs and it holds a positive, intraspecific occupancy-abundance relationship, in which increased patch occupancy increases species density within inhabiting patches. In a constant environment, while local abundance dynamics approach toward a stable equilibrium point, a fixed spatial arrangement of species can be retained through this coupled dynamics. However, in fluctuating environments where existence of such stable equilibriums is highly uncertain, it may involve continuous transitions from one community state to another as species re-organized themselves over space through the rapid changes in local species abundances. While some of the inhabiting patches are destroyed exogenously or endogenously, or species responses to increasing environmental fluctuations vary increasingly with time, discontinuous transitions into an abrupt, irreversible state of the community dynamics may occur, as with this effect the inherent positive relationship between occupancy and abundance of species is no longer maintained.

关键词： spatial organization competition-colonization tradeoffs spatial coexistence occupancy-abundance relationship

Mosquito larvicidal effect of orthophosporic acid and lactic acid individually or their combined form on Aedes aegypti

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Asian Pacific Journal of Tropical Medicine 2010年第12期3卷 954-956页

作者： Supratik chakraborty Someshwar Singha Goutam Chandra Mosquito and Microbiology Research Units Parasitology LaboratoryDepartment of ZoologyBurdwan UniversityWest BengalIndia

Objective:To observe the effect of two common organic acids on the larvae of Aedes aegypti (***)(L),the natural vector of dengue fever/dengue hemorrhage fever,chikugunya and allergic skin reaction especially in ***:Two common organic acids(lactic acid and orthophosporic acid of gradually increasing concentration) were used against laboratory reared third instars larvae of *** in order to observe the rate of mortality after 8.16 and 24 h of post exposure respectively in ***:Larval mortality rates recorded were in the following sequences:orthophosphoric acid and lactic acid at 1:1 combination >orthophosphoric acid>lactic ***:These two organic acids may be used perfectly in combination (1:1) along with other conventional vector control methods to reduce the *** population, especially in those areas where surveillance and supervisory mechanism are poor or insufficient.

关键词： Orthophosporic acid Lactic acid Ae.aegypti Mosquito larvicidal Synergistic effect

Computational study of some potential inhibitors of COVID-19:A DFT analysis

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Quantitative Biology 2022年第4期10卷 341-350页

作者： Prabhat Ranjan Kumar Gaurav Tanmoy chakraborty Department of Mechatronics Engineering Manipal University JaipurDehmi Kalan 303007India Department of Chemistry and Biochemistry School of Basic Sciences and ResearchSharda UniversityGreater Noida 201310India

Background:There is an urgent demand of drug or therapy to control the *** July 22,2021 the worldwide total number of cases reported is more than 192 million and the total number of deaths reported is more than 4.12 *** countries have given emergency permission for use of repurposed drugs for the treatment of COVID-19 *** report presents a computational analysis on repurposing drugs—tenofovir,bepotastine,epirubicin,epoprostenol,tirazavirin,aprepitant and valrubicin,which can be potential inhibitors of the ***:Density functional theory(DFT)technique is applied for computation of these repurposed *** geometry optimization,functional B3LYP/6-311G(d,p)is selected within DFT ***:DFT based descriptors—highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gap,molecular hardness,softness,electronegativity,electrophilicity index,nucleophilicity index and dipole moment of these species are *** and Raman activities are also analysed and *** result shows that the HOMO-LUMO gap of these species varies from 1.061 eV to 5.327 *** aprepitant with a HOMOLUMO gap of 1.419 eV shows the maximum intensity of IR(786.176 km mol‒1)and Raman spectra(15036.702 a.u.).Conclusion:Some potential inhibitors of COVID-19 are studied by using DFT *** study shows that epirubicin is the most reactive compound whereas tenofovir is found to be the most *** analysis and clinical trials of these compounds will provide more insight.

关键词： COVID-19 repurposing drug density functional theory HOMO-LUMO epirubicin aprepitant

Earthquake response of wrap faced embankment on soft clay soil in Bangladesh

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 703-718页

作者： Ripon Hore Sudipta chakraborty Kamruzzaman Kamrul Ayaz Mahmud Shuvon Mehedi AAnsary LGED DhakaBangladesh Kongju National University CheonanSouth Korea Department of Civil Engineering Bangladesh University of EngineeringDhakaBangladesh Bangladesh Network Office for Urban Safety(BNUS) Bangladesh University of Engineering and TechnologyDhakaBangladesh Department of Civil Engineering Bangladesh University of Engineering and TechnologyDhakaBangladesh

A wrap-faced embankment model on soft clay soil subjected to earthquake motion was investigated in this *** study was conducted both experimentally using a shaking table and numerically using PLAXIS 3D *** amplification of acceleration,displacement,pore water pressure,and strain response were measured while varying input accelerations and surcharge *** histories of the Kobe record of the 1995 Hanshin earthquake were used as the input seismic *** input acceleration was 0.05 g,0.1 g,0.15 g,and 0.2 g,and different surcharge pressures were 0.70 kPa,1.12 kPa,and 1.72 kPa with relative density of Sylhet sand fixed to 48%.The output data from the shaking table tests and the numerical analysis performed through the PLAXIS 3D software were compared,and these findings were also compared with some earlier similar *** acceleration amplification,displacement,pore water pressure,and strain(%)changed along the elevation of the embankment and acceleration response increased with the increase in base *** increase was more noticeable at higher *** findings enrich the knowledge of predicting the dynamic behavior of wrap-faced embankments and enable the design parameters to be adjusted more accurately.

关键词： shaking table test soft clayey soil kobe earthquake seismic wave wrap-faced soil embankment

Effect of magnetic field on Oldroyd-B type nanofluid flow over a permeable stretching surface

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Propulsion and Power Research 2018年第3期7卷 238-246页

作者： Kalidas Das Tanmoy chakraborty Prabir Kumar Kundu Department of Mathematics A.B.N.Seal CollegeCooch BeharWest Bengal 736101India Department of Engineering Science Academy of TechnologyHooghly 712121India Department of Mathematics Jadavpur UniversityKolkataWest Bengal 700032India

This article is conceded to explore the influence of magnetic flux on a two dimensional incompressible Oldroyd-B type nanofluid past a heat generating/absorbing permeable expanding *** by some appropriate similarity transformations,the fundamental PDEs are converted into a self similar system of coupled,non-linear *** findings are gained by taking the help of the Runge–Kutta Gill based Shooting *** visualize the influences of related parameters concerning the flow,on velocity,temperature and concentration distributions are represented through *** fallouts for the local Nusselt number and Sherwood number are charted for various parametric situations to offer interesting aspects of the *** existence of magnetic flux the momentum boundary layer width declines rapidly with relaxation time and velocity slip whereas,the temperature boundary layer width enhances significantly with heat source,Brownian motion and thermophoresis *** Nusselt number falls a lot with heat source,velocity slip and Brownian motion parameter but reverse result is notified for Sherwood number for the ***,the obtained numerical outcomes for particular cases are compared with those of the existing data in the open literature and,are found in excellent harmony.

关键词： Oldroyd-B type nanofluid Slip velocity Magnetic field Heat generation/absorption Suction/injection

Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

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Defence Technology（防务技术） 2016年第6期12卷 490-495页

作者： Gopa chakraborty R. REJEESH S.K. ALBERT Materials Technology Division Indira Gandhi Centre for Atomic Research Kalpakkam 603102 India National Institute of Technology Surathkal India

DMR-249 A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249 A steel welds made using this electrode has been assessed using implant test. Implant tests were conducted using this electrode at two different levels of diffusible hydrogen, measured using gas chromatography technique. It is observed that both the steel and the welding consumable are not susceptible to hydrogen assisted cracking even with a high diffusible hydrogen level of 9 m L/100 g of weld metal. In implant tests, specimen did not fracture even after loading to stress levels higher than the yield strength of the base metal. The good resistance of this steel and the welding consumable, even with high levels of diffusible hydrogen, is attributed to absence of a susceptible microstructure in both the weld metal and heat affected zone. Hence, this study shows that, in the absence of a susceptible microstructure, hydrogen assisted cracking is unlikely to occur even if hydrogen level is high. It also confirms that in welding of DMR-249 A with indigenously developed E8018 C1 electrode, hydrogen assisted cracking is not a concern and no preheating is required to avoid it during welding.

关键词： HSLA steel Hydrogen assisted cracking Diffusible hydrogen Implant test Lower critical stress