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61.
Manjima Bhattacharya Riya Chakraborty Arjun Dey Ashok Kumar Mandal Anoop Kumar Mukhopadhyay 《Ceramics International》2013,39(2):999-1009
The present experiments were focused on nanoindentation behaviour and the attendant “micro-pop-in” in a dense (~95% of theoretical) coarse-grain (~20 μm) alumina ceramic as a function of loading rate variations at three constant peak loads in the range of 105–106 μN. Based on the experimental results here we report for the first time, to the best of our knowledge, an increase in intrinsic nano scale contact resistance as well as the nanohardness with the loading rate. These observations were explained in terms of the correlation between the nanoscale plasticity and shear stress active just underneath the nanoindenter. 相似文献
62.
63.
Nintu Mandal S. C. Datta K. M. Manjaiah B. S. Dwivedi R. Kumar P. Aggarwal 《Polymer-Plastics Technology and Engineering》2018,57(17):1760-1770
Novel zincated nanoclay polymer composites (ZNCPCs) with variable percentage of commercial bentonite and nanobentonite (8%, 10% and 12% of monomer for each case) were synthesized. Polyacrylic acid-Polyacrylamide copolymer was synthesized using N, N-Methylene bisacrylamide as crosslinker and ammonium persulfate as initiator. Clays as well as ZNCPCs were characterized by XRD, SEM, TEM and FTIR. 12% nanoclay containing formulation showed slowest release rate. ZNCPCs containing 8% clay recorded highest Zn content as well as highest equilibrium water absorbency. Biodegradation study revealed that Aspergillus spp was more effective as compared with Trichoderma spp in degradation of ZNCPCs. 相似文献
64.
Jagadeeswari Sivanadanam Ramesh Mukkamala Sudip Mandal Raman Vedarajan Noriyoshi Matsumi Indrapal Singh Aidhen Kothandaraman Ramanujam 《International Journal of Hydrogen Energy》2018,43(9):4691-4705
Six triphenylamine-based dyes were explored for their application in dye-sensitized solar cells (DSSCs). Dyes 1–3 and dyes 4–6 possess cyanoacrylic acid (C-acceptor) and rhodanine-3-acetic acid (R-acceptor), respectively. Stilbene (in dyes 2 and 5) and bis(styryl)benzene (in dyes 3 and 6) were used as π-spacers. There is no π-spacer in the dye 1 and 4. To elucidate the role of π-spacers, optical, electrochemical, and photovoltaic properties of the dyes were studied. Among C-acceptor dyes, dye 2 exhibits the highest light-to-electricity conversion efficiency of 4.45%, followed by dye 3 (4.16%). Similarly, among R-acceptor dyes, dye 5 is the best. These results indicate that stilbene is a better π-spacer over bis(styryl)benzene. Although bis(styryl)benzene could extend the light absorption range (in dye-adsorbed TiO2 film), its tendency to promote intermolecular π-π stacking is possibly the reason for its poor performance in DSSCs. Furthermore, the conjugation break in the R-acceptor moiety attached to the TiO2 surface limits the electron injection of R-acceptor dyes poorer than C-acceptor dyes. Density functional theory calculations were performed for the dye-(TiO2)8 cluster, assuming a bidentate chelation of a carboxylic acid group with Ti4+ of TiO2 anatase. The natural bond orbital (NBO) analysis indicated relatively more electron-accepting ability of cyanoacrylic acid over rhodanine-3-acetic acid. 相似文献
65.
A three-phase ac-to-dc power transistor converter that is suitable for speed control of a dc motor and for a variable dc power supply is investigated. The availability of power transistors of fairly high power rating has made the task of ac-to-dc conversion relatively easy due to simplification of the converter circuit configuration. The external performance characteristics of the power transistor converter-controlled separately excited dc motor are obtained by employing the equal pulsewidth modulation (EPWM) control technique with 18 pulses per half-cycle of the supply voltage and are verified experimentally. There is good agreement between experimental and theoretical results. The external performance is also evaluated under constant torque operation. The use of inductance-capacitance (LC) filters for reducing the effect of predominant supply harmonics is briefly discussed. Experimental oscillograms of some typical waveforms are illustrated to verify the basic principles of operation. 相似文献
66.
Krishna C. Mandal Sung Hoon Kang Michael Choi Job Bello Lili Zheng Hui Zhang Michael Groza Utpal N. Roy Arnold Burger Gerald E. Jellison David E. Holcomb Gomez W. Wright Joseph A. Williams 《Journal of Electronic Materials》2006,35(6):1251-1256
High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd0.9Zn0.1Te (CZT) single crystals have been grown by a controlled vertical Bridgman technique using in-house zone refined precursor
materials (Cd, Zn, and Te). A state-of-the-art computer model, multizone adaptive scheme for transport and phase-change processes
(MASTRAP), is used to model heat and mass transfer in the Bridgman growth system and to predict the stress distribution in
the as-grown CZT crystal and optimize the thermal profile. The model accounts for heat transfer in the multiphase system,
convection in the melt, and interface dynamics. The grown semi-insulating (SI) CZT crystals have demonstrated promising results
for high-resolution room-temperature radiation detectors due to their high dark resistivity (ρ≈2.8 × 1011 Θ cm), good charge-transport properties [electron and hole mobility-life-time product, μτe≈(2–5)×10−3 and μτh≈(3–5)×10−5 respectively, and low cost of production. Spectroscopic ellipsometry and optical transmission measurements were carried out
on the grown CZT crystals using two-modulator generalized ellipsometry (2-MGE). The refractive index n and extinction coefficient
k were determined by mathematically eliminating the ∼3-nm surface roughness layer. Nuclear detection measurements on the single-element
CZT detectors with 241Am and 137Cs clearly detected 59.6 and 662 keV energies with energy resolution (FWHM) of 2.4 keV (4.0%) and 9.2 keV (1.4%), respectively. 相似文献
67.
Effect of environmental pollutants on the C-reactive protein of a freshwater major carp, Catla catla
C-reactive proteins (CRP) have been affinity purified to electrophoretic homogeneity from the sera of major carp, Catla catla before and after exposure to environmental pollutants. Exposure to these pollutants elevate the levels of circulating CRPs to 2.8-3.5 times the normal values. Kinetic studies of metal intoxication indicate that a unique molecular variant of CRP is present in the serum at the peak level of acute phase induction, and this variant coexists with normal CRPs. Carbohydrate analysis and lectin binding reveals that these CRPs are glycoproteins differing significantly in total carbohydrate contents. Their electrophoretic mobilities in native gel are different but become identical on desialylation and deglycosylation implying that the molecular variants vary in the glycan parts. All these forms of CRP contain two nonidentical subunits of Mr 22 and 29 kDa. Examination of their immunological crossreactivity demonstrate their similarity in overall molecular topology but their differences in the quantitative extent of binding are reflected. 相似文献
68.
J. B. Mandal B. Bandyopadhyay B. Ghosh H. Rajagopal A. Sequeira J. V. Yakhmi 《Journal of Superconductivity and Novel Magnetism》1996,9(2):253-257
Rietveld analysis of powder neutron diffraction pattern recorded on Sr-based 1201-phase superconductor (T c =53 K), (Hg0.7Cr0.3)Sr2CuO4+δ shows that the oxygen atoms at O(3) site are disordered atx=y=0.3712. This fourfold split site has a total combined occupancy of ~80% and is the only occupied site in the (Hg, Cr)O plane. 相似文献
69.
A template synthesis technique of encapsulating DNA molecules inside polypyrrole (PPy) nanotubes, termed as DNA-PPy nanocapsule, has been described here. The insertion of DNA molecules inside polypyrrole nanotubes is spontaneous in nature. The structural characterizations and possible applications of DNA-PPy nanocapsule in bio-sensing devices have been discussed. 相似文献
70.
Mandal S. Sarpeshkar R. 《IEEE transactions on circuits and systems. I, Regular papers》2007,54(6):1177-1188
We investigate theoretical and practical aspects of the design of far-field RF power extraction systems consisting of antennas, impedance matching networks and rectifiers. Fundamental physical relationships that link the operating bandwidth and range are related to technology dependent quantities like threshold voltage and parasitic capacitances. This allows us to design efficient planar antennas, coupled resonator impedance matching networks and low-power rectifiers in standard CMOS technologies (0.5-mum and 0.18-mum) and accurately predict their performance. Experimental results from a prototype power extraction system that operates around 950 MHz and integrates these components together are presented. Our measured RF power-up threshold (in 0.18-mum, at 1 muW load) was 6 muWplusmn10%, closely matching the predicted value of 5.2 muW. 相似文献