Temperature dependent structure formation and photoluminescence studies of a series of magnesium-based coordination networks

Calderone, P.J.,Banerjee, D.,Plonka, A.M.,Kim, S.J.,Parise, J.B. Elsevier Sequoia [etc.] 2013 Inorganica chimica acta Vol.394 No.-

A series of three magnesium trimesate coordination networks was synthesized from identical reaction mixtures by varying synthetic temperature. Mg(HBTC)(DMF)<SUB>2</SUB>.[(CH<SUB>3</SUB>)<SUB>2</SUB>NH] (1; BTC=trimesate; space group P6<SUB>3</SUB>/m, a=16.596(4)A, c=14.351(8)A) crystallizes at 65<SUP>o</SUP>C, Mg<SUB>3</SUB>(BTC)(HCOO)<SUB>3</SUB>(DMF)<SUB>3</SUB> (2; space group P@?3, a=13.928(2)A, c=8.025(6)A) crystallizes at 100<SUP>o</SUP>C, and Mg<SUB>3</SUB>(BTC)<SUB>2</SUB>(DMF)<SUB>4</SUB> (3; space group P2<SUB>1</SUB>/c, a=17.490(4)A, b=11.940(2)A, c=18.460(4)A, β=116.87(3)<SUP>o</SUP>) crystallizes at a temperature of 180<SUP>o</SUP>C. Each network contains metal-coordinated solvent DMF molecules, but thermodynamics and solvent hydrolysis play major roles in structure formation. Compounds 1 and 2 are two-dimensional networks which incorporate hydrolysis byproducts. Compound 3 is a three-dimensional network and shows no inclusion of byproducts. The series follows the trend of increased network connectivity resulting from increased temperature. Each of the networks show a weak photoluminescence response, suggesting that coordinated solvent molecules and interlayer species play a role in quenching photoluminescence.

Single spin asymmetry A_N in polarized proton-proton elastic scattering at s=200 GeV

STAR Collaboration,Adamczyk, L.,Agakishiev, G.,Aggarwal, M.M.,Ahammed, Z.,Alakhverdyants, A.V.,Alekseev, I.,Alford, J.,Anson, C.D.,Arkhipkin, D.,Aschenauer, E.,Averichev, G.S.,Balewski, J.,Banerjee, A North-Holland Pub. Co 2013 Physics letters: B Vol.719 No.1

We report a high precision measurement of the transverse single spin asymmetry A<SUB>N</SUB> at the center of mass energy s=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The A<SUB>N</SUB> was measured in the four-momentum transfer squared t range 0.003≤|t|≤0.035 (GeV/c)<SUP>2</SUP>, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of A<SUB>N</SUB> and its t-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.

Transition from mobility-activated small polaron to carrier density-activated conduction of <i>sol-gel</i>-derived highly-oriented CuAlO₂ thin film and enhanced thermoelectric properties

Banerjee, A.N.,Joo, S.W. Elsevier 2018 CERAMICS INTERNATIONAL Vol.44 No.6

<P><B>Abstract</B></P> <P>CuAlO<SUB>2</SUB> is a technologically important material having diverse applications, including superior thermoelectric properties. Its unique crystallographic structure manifests an anisotropic environment for the charge carriers and phonons, which is considered to be the reason for the enhancement of the thermopower. To exploit this novel property, a controlled <I>sol-gel</I> deposition technique is adopted to realize highly <I>c</I>-axis-oriented growth of CuAlO<SUB>2</SUB> thin film on Si and glass substrates. Thermoelectric measurements are performed in such a way that the carriers are confined along the <I>a-b</I> plane of the nanocrystal, which is parallel to the substrate. This allows a two-dimensional confinement of the charge carriers, leading to enhanced thermoelectric properties. Additionally, the temperature-dependent electrical characterizations depict two different charge-transport regimes with a cross-over at 360K. The low-temperature region corresponds to the mobility-activated small-polaron conduction and the high-temperature region belongs to the semiconductor-type carrier-density-activated conduction. Calculation of polaron activation energy from low-temperature regime indicates considerable influence of band carriers (hole) on the polaronic levels, due to which the above-mentioned transition is manifested. Calculations of activation and Fermi energy from high-temperature regime reveal a deep acceptor level and shallow Fermi level, which is typical of a non-degenerate semiconductor with acceptors not fully ionized at room temperature.</P>

Design and Modeling of a Capacitor Bank Power Supply for Fast Charging

Surender Kumar Sharma,Pankaj Deb,R. Shukla,P. Banerjee,T. Prabaharan,R. Das,B. Das,B. Adhikary,A. Shyam 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.61

Power supplies used in pulsed power applications are rugged, and the capacitor bank charges rapidly. The capacitor bank is fully charged to the rated voltage in a minimum time so as to reduce the dielectric stress on the capacitors and to increase their life. When the capacitor bank is discharged in the load much Electromagnetic Interference (EMI) and Electromagnetic Pulse (EMP) due to high currents discharges is generated, which can damage the electronic circuitry in the power supply if proper shielding & isolation are not provided to it. We have designed and fabricated a compact, rugged and low-cost high voltage (HV) power supply for a 114-kJ, 40-kV capacitor bank. The power supply consists of a high voltage transformer (5.25 kVA, 230 V/35 kV, 50 Hz), a high voltage diode (Semikron Make PIV 110 kV, 150 mA) and a charging resistor placed in a tank filled with oil. The charging resistors value is selected after a PSPICE simulation of the charging circuit for different values of the charging resistor. The charging current is limited with the selected resistor so that it does not exceed the current limit of the HV transformer & diode. The input voltage to the high voltage transformer is given through autotransformer, which rotates from 0 ?230 volts in 40 sec with a single-phase synchronous motor. The capacitor bank is charged to 40 kV in a minute after that, the power supply is decoupled from the capacitor bank by using a pneumatic decoupling switch, then the capacitor bank's switch is triggered to deliver the capacitor bank's energy to the load. Control and protection in the power supply is provided for its safe operation. The monitoring of charging voltage is done with a digital display meter with fiber optic isolation by using a V-F and then F-V converter in order to provide electrical isolation.

A comparative study of the effect of Pd-doping on the structural, optical, and photocatalytic properties of sol-gel derived anatase TiO₂ nanoparticles

Banerjee, A.N.,Hamnabard, N.,Joo, S.W. Ceramurgica ; Elsevier Science Ltd 2016 Ceramics international Vol.42 No.10

Pd-doped anatase TiO<SUB>2</SUB> nanoparticles were synthesized by a modified sol-gel deposition technique. The synthetic strategy is applicable to other transition and post-transition metals to obtain phase-pure anatase titania nanoparticles. This is important in the sense that anatase titania forms the most hydroxyl radicals (compared to other polymorphs like rutile, brookite, etc.) for better photocatalytic performance. XRD and Raman data confirm the phase-pure anatase formation. Doping of Pd<SUP>2+</SUP> into Ti<SUP>4+</SUP> sites (for substitutional doping) or interstitial sites (for interstitial doping) creates strain within the nanoparticles and is reflected in the XRD peak broadening and Raman peak shifts. This is because of the ionic radii difference between Ti<SUP>4+</SUP>(~68pm) and Pd<SUP>2+</SUP>(~86pm). XPS data confirm the formation of high surface titanol groups at the nanoparticle surface and a large number of loosely bound Ti<SUP>3+</SUP>-O bonds, both of which considerably enhance the photocatalytic activity of the doped nanoparticles. A comparative study with other metal doping (Ga) shows that TiO<SUB>2</SUB>: Pd nanoparticles have more Ti<SUP>3+</SUP>-O bonds, which enhance the charge transfer rate and hence improve the photocatalytic activity compared to other transition and post-transition metal-doped titania nanostructures.

Measurement of Brownian motion of nanoparticles in suspension using a network-based PTV technique

A. Banerjee,C. K. Choi,K. D. Kihm 한국가시화정보학회 2004 KOREA-JAPAN Joint Seminar on Particle Image Veloci Vol.- No.-

A comprehensive three-dimensional nano-particle tracking technique in micro- and nano-scale spatial resolution using the Total Internal Reflection Fluorescence Microscope (TIRFM) is discussed. Evanescent waves from the total internal reflection of a 488㎚ argon-ion laser are used to measure the hindered Brownian diffusion within few hundred nanometers of a glass-water interface. 200-㎚ fluorescence-coated polystyrene spheres are used as tracers to achieve three-dimensional tracking within the near-wall penetration depth. A novel ratiometric imaging technique coupled with a neural network model is used to tag and track the tracer particles. This technique allows for the determination of the relative depth wise locations of the particles. This analysis, to our knowledge is the first such three-dimensional ratiometric nano-particle tracking velocimetry technique to be applied for measuring Brownian diffusion close to the wall.

On numerical equivalence for algebraic cobordism

Banerjee, A.,Park, J. North-Holland Pub. Co 2016 Journal of pure and applied algebra Vol.220 No.1

<P>We define and study the notion of numerical equivalence on algebraic cobordism cycles. We prove that algebraic cobordism modulo numerical equivalence is a finitely generated module over the Lazard ring, and it reproduces the Chow group modulo numerical equivalence. We show this theory defines an oriented Borel-Moore homology theory on schemes and oriented cohomology theory on smooth varieties. We compare it with homological equivalence and smash-equivalence for cobordism cycles. For the former, we show that homological equivalence on algebraic cobordism is strictly finer than numerical equivalence, answering negatively the integral cobordism analogue of the standard conjecture (D). For the latter, using Kimura finiteness on cobordism motives, we partially resolve the cobordism analogue of a conjecture by Voevodsky on rational smash-equivalence and numerical equivalence. (C) 2015 Elsevier B.V. All rights reserved.</P>

Crop insurance model to consolidate academia-industry cooperation: a case study over Assam, India

Subhro Banerjee,A. C. Pandey 대한공간정보학회 2019 Spatial Information Research Vol.27 No.6

Agriculture is one of the deciding factors of Indian economy, contributing almost 17% of the total GDP. Every year, crops are lost due to natural disasters. This academic research may provide a solution for a longstanding problem in the industry. Crop insurance is one of the most effective ways to not only compensate loss, but also to increase poor farmers’ resilience. Remote sensing has huge potential in the crop insurance market; it can be exploited for vulnerability mapping, damage assessment, risk mapping, and various other aspects. The purpose of this study was to present a method for evaluating crop vulnerability over an area using remote sensing and Geographic Information System (GIS), followed by an assessment of crops damaged due to flood. For application purposes, a crop risk map was prepared from a GIS model for the determination of crop insurance parameters. The study area selected (i.e., the Morigaon and Nagaon districts of Assam) is very much flood-prone. The districts have almost 50% agricultural land of the total land cover, thus making the crops very vulnerable to recurrent flooding. For this study, assessment of damage to crops due to flood was performed for a full year, followed by crop risk map generation from the GIS model. The results revealed that 345 km2 of land was inundated by flood in August 2016. Due to the flooding, 1435.08 km2 of agricultural land bearing crops was damaged at different levels. The crop risk map depicts 103.33 km2 of cropland at high risk due to flood.

Giant Electron-Phonon Coupling and Deep Conduction Band Resonance in Metal Halide Double Perovskite

Steele, Julian A.,Puech, Pascal,Keshavarz, Masoumeh,Yang, Ruoxi,Banerjee, Subhasree,Debroye, Elke,Kim, Cheol Woong,Yuan, Haifeng,Heo, Nam Ho,Vanacken, Johan,Walsh, Aron,Hofkens, Johan,Roeffaers, Maart American Chemical Society 2018 ACS NANO Vol.12 No.8

<P>The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs<SUB>2</SUB>AgBiBr<SUB>6</SUB><I>via</I> a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-<I>via</I> the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two “single” and “double” perovskite materials branches.</P> [FIG OMISSION]</BR>

Changes in Physiological Profile of Indian Women Boxers During a Six Week Training Camp

( Pinaki Chatterjee ),( A. K. Banerjee ),( P. Majumdar ),( Pratima Chatterjee ) 한국스포츠정책과학원(구 한국스포츠개발원) 2006 International Journal of Applied Sports Sciences Vol.18 No.2

Women`s boxing is a newly recognized game. The purpose of the present study was to frame out the physiological profile of Indian women boxers. The present study is based on a sample of 45 female boxers attending a Senior National Women`s Boxing Camp, at sports Authority of India, Southern Center, Bangalore. Each subject was evaluated for selected physiological variables at the beginning and end of the 6 week training camp. Standard techniques and procedures were followed for all the evaluations. Data were subjected to statistical treatment such as mean and standard deviation. Test of significance t-test (for paired samples) was applied to assess the difference in pre- and post-test. Results reveal that mean (± Standard Deviation) Basal heart rate, VO2max, O2 debt and maximum ventilation of the boxers, as found in the pre-test were 70 ± 7 beats/min, 48.6 ± 6.8 ml/kg/min, 4.33 ± 0.73 liter, 93.8 ± 11.1liter/min respectively. Training camp had the positive effect of improving VO2max (P<0.01). No significant change was observed in O2 debt, and maximum heart rate. A norm of desired level for physiological status of the women boxers may be formulated after sufficient data of their international counterparts are available. However, further improvement of certain parameters is required to withstand the physiological demands of the game.