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111.
We developed a simple, facile route for the synthesis of BF(2) complexes of prodigiosin type oligopyrroles and their cholesterol conjugates. This route gives an access to synthesize any desired meso-aryl-substituted 3-pyrrolyl BODIPYs which were not easily accessible earlier. 相似文献
112.
Tiwari AD Mishra AK Mishra SB Mamba BB Maji B Bhattacharya S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1050-1056
The thiocarbohydrazone Schiff-base ligand with a nitrogen and sulphur donor was synthesized through condensation of pyridine-2-carbaldehyde and thiocarbohydrazide. Schiff-base ligands have the ability to conjugate with metal salts. A series of metal complexes with a general formula [MCl2(H2L)]·nH2O (MNi, Co, Cu and Zn) were synthesized by forming complexes of the N1,N5-bis[pyridine-2-methylene]-thiocarbohydrazone (H2L) Schiff-base ligand. These metal complexes and ligand were characterized by using ultraviolet-visible (UV-Vis), Fourier Transform Infrared (FT-IR), 1H and 13C NMR spectroscopy and mass spectroscopy, physicochemical characterization, CHNS and conductivity. The biological activity of the synthesized ligand was investigated by using Escherichia coli DNA as target. The DNA interaction of the synthesized ligand and complexes on E. coli plasmid DNA was investigated in the aqueous medium by UV-Vis spectroscopy and the binding constant (Kb) was calculated. The DNA binding studies showed that the metal complexes had an improved interaction due to trans-geometrical isomers of the complexes than ligand isomers in cis-positions. 相似文献
113.
An inverse approach for the identification of the time-dependent localized interaction pressure between a structure and an
explosive has been proposed and developed. In this approach, surface measurements of structural response (displacement and
velocity) are integrated with numerical simulations to identify the spatial and time-dependent interaction pressure (i.e.
the normal traction) on a structure surface. For verification and validation purposes, numerical simulations are used to (a)
generate the time-dependent displacement and velocity fields on the free surface of the specimen at specified time intervals,
(b) form a blast wave and compute the resulting interaction traction field between the structure and blast wave on the interaction
interface for comparison to inverse predictions. In particular, validation of the proposed approach was performed using numerical
simulation results for an underwater explosion, with excellent agreement between the identified interaction traction and the
simulation generated interaction traction up to and including the maximum traction condition. To demonstrate the potential
of the method, the proposed inverse procedure was employed to estimate the interaction traction field on a thin aluminum specimen
subjected to transient pressure loading through detonation of explosive buried in sand. 相似文献
114.
Adrian Renfer Manish K. Tiwari Thomas Brunschwiler Bruno Michel Dimos Poulikakos 《Experiments in fluids》2011,51(3):731-741
Hydrodynamics in microcavities with cylindrical micropin fin arrays simulating a single layer of a water-cooled electronic
chip stack is investigated experimentally. Both inline and staggered pin arrangements are investigated using pressure drop
and microparticle image velocimetry (μPIV) measurements. The pressure drop across the cavity shows a flow transition at pin
diameter–based Reynolds numbers (Re
d
) ~200. Instantaneous μPIV, performed using a pH-controlled high seeding density of tracer microspheres, helps visualize vortex
structure unreported till date in microscale geometries. The post-transition flow field shows vortex shedding and flow impingement
onto the pins explaining the pressure drop increase. The flow fluctuations start at the chip outlet and shift upstream with
increasing Re
d
. No fluctuations are observed for a cavity with pin height-to-diameter ratio h/d = 1 up to Re
d
~330; however, its pressure drop was higher than for a cavity with h/d = 2 due to pronounced influence of cavity walls. 相似文献
115.
Nonlinear Dynamics - We consider the theoretical maximum extractable average power from an energy harvesting device attached to a vibrating table which provides a unidirectional displacement... 相似文献
116.
Dr S. Tiwari 《Contemporary Physics》2013,54(1):81-82
This article, which is in two parts, surveys the wide application of scattering experiments to studies of the structures of solids and liquids. Part 1 outlines the general principles, and shows how the angular distribution of a scattered radiation is related by Fourier transform to correlations in the distributions of electrons and nuclei in the scattering target, citing the use of X-rays and of neutrons in determining time-averaged density distributions. Part 2 (to appear in the next issue) discusses the time-dependent aspects of the distributions for solids and liquids, including superfluid helium, and also of dynamical distributions of magnetization (or angular momentum) density, and examines the present limitations and future possibilities of scattering experiments. 相似文献
117.
This paper reports the simulative analyses to investigate the impact of different pulse shapes on DP-DQPSK modulation for high-spectral efficient DWDM transmission at 112 Gbps per channel. In the simulation model we have considered three different pulse shapes viz. NRZ, 50% duty cycle RZ (RZ50) and 67% duty cycle RZ (RZ67) in symbol-aligned and symbol-interleaved format. The analysis has been carried out for various linear and nonlinear system impairments where the pulse is subjected to degradation under the influence of amplified spontaneous emission (ASE) noise, group velocity dispersion (GVD), cross-phase modulation (XPM) and polarization mode dispersion (PMD) and thus, limiting the system performance. Results show that the RZ50 pulse shape for DP-DQPSK with symbol interleaving shows the maximum tolerance for the various system degradations in long haul DWDM transmission. Even the system based on the NRZ pulse shape can gain significant improvement from the symbol-interleaving. 相似文献
118.
M. K. Tiwari P. Gupta A. K. Sinha S. R. Kane A. K. Singh S. R. Garg C. K. Garg G. S. Lodha S. K. Deb 《Journal of synchrotron radiation》2013,20(2):386-389
A microfocus X‐ray fluorescence spectroscopy beamline (BL‐16) at the Indian synchrotron radiation facility Indus‐2 has been constructed with an experimental emphasis on environmental, archaeological, biomedical and material science applications involving heavy metal speciation and their localization. The beamline offers a combination of different analytical probes, e.g. X‐ray fluorescence mapping, X‐ray microspectroscopy and total‐external‐reflection fluorescence characterization. The beamline is installed on a bending‐magnet source with a working X‐ray energy range of 4–20 keV, enabling it to excite K‐edges of all elements from S to Nb and L‐edges from Ag to U. The optics of the beamline comprises of a double‐crystal monochromator with Si(111) symmetric and asymmetric crystals and a pair of Kirkpatrick–Baez focusing mirrors. This paper describes the performance of the beamline and its capabilities with examples of measured results. 相似文献
119.
Prashant S. Umare Ajaykumar J. Tiwari Robin Antony Gopal L. Tembe Bhavna Trivedi 《应用有机金属化学》2007,21(8):652-660
Complexes of titanium(IV) with bulky phenolic ligands such as 2‐tert‐butyl‐4 methylphenol, 2, 4‐di‐tert‐butyl phenol and 3,5‐di‐tert‐butyl phenol were prepared and characterized. These catalyst precursors, formulated as [Ti(OPh*)n(OPri)4?n] (OPh* = substituted phenol), were found to be active in polymerization of ethylene at higher temperatures in combination with ethylaluminum sesquichloride (Et3Al2Cl3) as co‐catalyst. It was observed that the reaction temperature and ethylene pressure had a pronounced effect on polymerization and the molecular weight of polyethylene obtained. In addition, this catalytic system predominantly produced linear, crystalline ultra‐low‐molecular‐weight polyethylenes narrow dispersities. The polyethylene waxes obtained with this catalytic system exhibit unique properties that have potential applications in surface coating and adhesive formulations. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
120.
We study the asymptotic properties of both the horizontal and vertical shift functions based on independent ranked set samples
drawn from continuous distributions. Several tests derived from these shift processes are developed. We show that by using
balanced ranked set samples with bigger set sizes, one can decrease the width of the confidence band and hence increase the
power of these tests. These theoretical findings are validated through small-scale simulation studies. An application of the
proposed techniques to a cancer mortality data set is also provided.
Part of the research was conducted while Kaushik Ghosh was visiting Statistical Research and Applications Branch of the National
Cancer Institute on an Intergovernmental Personnel Assignment. 相似文献