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111.
We experimentally probe molecular ionization and dissociation of methane molecules in the gas phase upon their irradiation by intense pulses of white light that spans the wavelength range 500-850 nm. White light pulses are generated upon irradiation of BK7 glass by 36-fs-long pulses of intense 820 nm laser light. Comparison is made of the molecular fragmentation patterns obtained using white light that is depolarized with those obtained using single-color (820 nm) light that is highly chirped. On the basis of such comparison, we make hitherto-unavailable estimates of the in situ intensity of white light pulses. Results obtained using white light also indicate that resonances apparently do not play any role in the ionization dynamics that ensue upon irradiation by intense, broadband light; neither are the dynamics affected by the polarization properties of the 820 nm light that is used to generate the white light. 相似文献
112.
V. T. Aher M. M. Palrecha A. V. Kulkarni G. C. Shah P. K. Mathur 《Fresenius' Journal of Analytical Chemistry》1999,364(4):362-364
A differential pulse voltammetric (DPV) method is proposed for the determination of palladium in deoxo catalysts, which are
used in recombination units of the cover gas system of nuclear reactors. The electrode system consists of hanging mercury
drop electrode (HMDE)/ platinum auxillary/ Ag-AgCl reference electrode. The supporting electrolyte consists of 0.02 M diammonium
tartrate + 0.08 M ammonia-ammonium chloride buffer at pH 9.0. Fe, Cu, Pb, Ni, Co and Zn did not interfere. The interference
by Cd could be eliminated using 0.005 M EDTA. The relative standard deviation of the proposed method was about 4.0% at ∼ 0.5%
palladium content in the catalyst. The method is simple, rapid and free from any possible interferences.
Received: 8 December 1998 / Revised: 11 January 1999 / Accepted: 18 January 1999 相似文献
113.
M. S. Alam A. A. S. Awwal P. McWhorter R. Venkatesh S. Mathur M. Dugar B. Grewal 《Optics & Laser Technology》2000,32(4)
A new synthetic discriminant-function-based amplitude modulated phase-only filtering technique is proposed for scale invariant pattern recognition. This technique has been found to yield improved correlation output when compared with the alternate techniques. The proposed technique is inherently suitable for optical implementation using the currently available spatial light modulators. Simulation results confirm the effectiveness of the proposed technique. 相似文献
114.
H-atoms in C2H5OH are rearranged by strong optical fields generated by intense, 100 fs long infrared laser pulses to form new bonds that lead to the H 3 + molecular ion. This observation appears to be against the expectation that exposure of molecules to intensities of the order of 1015 W cm?2 inevitably lead to multiple ionization of molecules followed by instantaneous Coulomb explosion into fragments. The polarization dependence of the H 3 + signal and of the energy content of H 3 + ions lead to believe that H-atom rear-rangement in ethanol occurs within a single 100 fs pulse. 相似文献
115.
S. P. Purohit K. C. Mathur 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):173-177
In this paper we report a study on the elastic scattering of electrons by lithium and sodium atoms in the presence of circularly
polarized resonant laser field within the framework of the two-state rotating wave approximation. The effect of laser on projectile
electrons is described by Volkov states. The frequency of the laser field is chosen to match with the 2s–3p (3s–3p) transition
frequency in lithium (sodium) atoms. The total and differential elastic cross sections with single photon exchange are calculated
for intermediate energies (50–150 eV) and laser intensity (107–1011 W cm-2).
An erratum to this article can be found online at http://dx.doi.org/.
An erratum to this article can be found at 相似文献
116.
Asmita Mukherjee R. Basu H. Dahiya L. Gamberg R. Godbole S. Gupta M. C. Kumar L. Magnea P. Mathews N. Mathur A. Mukherjee P. J. Mulders V. Ravindran A. Tripathi 《Pramana》2009,72(1):277-283
This is the report of the QCD working sub-group at the Tenth Workshop on High Energy Physics Phenomenology (WHEPP-X).
相似文献
117.
Shubhra Mathur Rishi Vyas Rohit Jain Praveen Kumar K. Sachdev S.K. Sharma 《Journal of Non》2011,357(16-17):3084-3087
Potentiodynamic polarization studies were carried out on nanocrystalline I, nanocrystalline II and nanocrystalline III states having crystallite size 35 ± 5 nm, 18 ± 2 nm and 10 ± 2 nm of the alloy Ti60Ni40 in 1 M H2SO4 aqueous medium. It was observed that the nanocrystalline III state exhibits superior corrosion resistance as compared to the nanocrystalline II and nanocrystalline I states of the alloy Ti60Ni40. XPS studies were also performed after corrosion test and it was observed that nanocrystalline III state contains only Ti2+ and Ti4+ species whereas nanocrystalline I and nanocrystalline II state contains Ti2+, Ti3+and Ti4+ along with some unoxidized metallic Ti0 in the case of nanocrystalline I state. Thus the small crystallite size and the presence of only Ti2+ and Ti4+ species in the form of TiO and TiO2 leads to the formation of a protective oxide film which is adherent, stable and improves the corrosion resistance of the nanocrystalline III state of the alloy Ti60Ni40. 相似文献
118.
Adsorption of Safranin-T from wastewater using waste materials- activated carbon and activated rice husks 总被引:6,自引:0,他引:6
Gupta VK Mittal A Jain R Mathur M Sikarwar S 《Journal of colloid and interface science》2006,303(1):80-86
Textile effluents are major industrial polluters because of high color content, about 15% unfixed dyes and salts. The present paper is aimed to investigate and develop cheap adsorption methods for color removal from wastewater using waste materials activated carbon and activated rice husk-as adsorbents. The method was employed for the removal of Safranin-T and the influence of various factors such as adsorbent dose, adsorbate concentration, particle size, temperature, contact time, and pH was studied. The adsorption of the dye over both the adsorbents was found to follow Langmuir and Freundlich adsorption isotherm models. Based on these models, different useful thermodynamic parameters have been evaluated for both the adsorption processes. The adsorption of Safranin-T over activated carbon and activated rice husks follows first-order kinetics and the rate constants for the adsorption processes decrease with increase in temperature. 相似文献
119.
Photocatalytic degradation of aniline at the interface of TiO2 suspensions containing carbonate ions
The degradation of aniline has been investigated using aqueous TiO2 suspensions containing carbonate ions as photocatalyst. The addition of carbonate to Degussa P-25 increased the number of active adsorption sites at its surface. For the TiO2 suspensions containing carbonate ions the intensity of adsorption of aniline increased to 6.9 x 10(2) from 5.5 x 10(2) mol(-1) dm(3) in case of bare TiO2 suspensions. This in turn results in the increased interfacial interaction of the photogenerated charge carriers with the adsorbed aniline and thus enhancing the rate of its photodecomposition to 6.5 x 10(-6) mol dm(-3) s(-1) compared to 2.7 x 10(-6) mol dm(-3) s(-1) in the absence of Na(2)CO(3). The maximum efficiency of this photocatalyst has been obtained upon addition of 0.11 mol dm(-3) of Na(2)CO(3) at pH 10.8. The photocatalytic action is understood by the simultaneous interaction of intermediates, *OH and CO*-(3), and their reactivity with aniline. Azobenzene, p-benzoquinone, nitrobenzene, and NH(3) have been identified as the major products of the photooxidation of aniline. Both the reactant and products have been followed kinetically. The photodegradation follows Langmuir-Hinshelwood Model. The mechanism of the occurring reactions has been analyzed and discussed. In the presence of Na(2)CO(3), 3 x 10(-3) mol dm(-3) of aniline could be photodegraded completely in about 6 h while all organic intermediates decomposed completely within about 10 h. 相似文献
120.
Appel L Fiz R Tyrra W Mathur S 《Dalton transactions (Cambridge, England : 2003)》2012,41(7):1981-1990
The synthesis and characterization of nine new heteroleptic alkoxides of niobium is described. Metathesis reactions of Nb(2)Cl(10) with (t)BuCH(2)OH and pyridine (py) or 4-dimethylaminopyridine (DMAP) affords monomeric octahedral complexes Nb(OCH(2)(t)Bu)(5)py (1) and Nb(OCH(2)(t)Bu)(5)DMAP (2), respectively, in high yields (>60%). The same reaction with (t)BuOH resulted in a chloro functionalized alkoxide Nb(O(t)Bu)(4)pyCl (3) and could not be pushed to complete removal of remaining Cl(-) ligand. The introduction of a chelating bidental ligand 3,3,3-trifluoro-1-(pyridine-2-yl)propen-2-ol (2-PyCHCOHCF(3)) (4') in the dimeric framework of Nb(2)(O(i)Pr)(10) (4') produced a heteroleptic, monomeric niobium complex Nb(O(i)Pr)(4)(2-PyCHCOCF(3)) (4) with significantly enhanced stability and volatility. As a comparison to (4), five different heteroaryl systems (5-9) with the same side chain have been synthesized and examined in order to understand the influence upon physio-chemical properties. All the new compounds (1-9) have been characterized by microanalysis, variable temperature multinuclear NMR spectroscopy, mass spectrometry, thermal analysis and single crystal X-ray diffraction studies ((3), (4) and (9)). The molecular structure of (3) revealed mononuclear species with Nb atoms present in the distorted octahedral environment of four (t)BuO, one chloride and one pyridine ligand. Compounds (4) and (9) consisting of four (i)PrO and a trifluoroheteroarylenolate exhibited a stronger distortion in the molecular geometry due to the rigidity of chelating β-alkenolate moiety. 相似文献