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101.
R. M. Godbole 《Physics letters. [Part B]》1986,180(4):395-399
A nonperturbative C
component in the quark fragmentation function, as suggested by the neutrino-induced like-sign dimuon data, contributes appreciably to muoproduction of charm. It is comparable in size to the perturbative QCD (photon-gluon fusion) contribution; and its inclusion gives a better fit to the charm muoproduction (muon-induced dimuon) data. 相似文献
102.
Sunil Abraham Greg Brockman Stephanie Sapp Anant P. Godbole 《Methodology and Computing in Applied Probability》2013,15(2):363-378
In this paper, we study the properties of k-omnisequences of length n, defined to be strings of length n that contain all strings of smaller length k embedded as (not necessarily contiguous) subsequences. We start by proving an elementary result that relates our problem to the classical coupon collector problem. After a short survey of relevant results in coupon collection, we focus our attention on the number M of strings (or words) of length k that are not found as subsequences of an n string, showing that there is a gap between the probability threshold for the emergence of an omnisequence and the zero-infinity threshold for ${\mathbb E}(M)$ . 相似文献
103.
Aishwarya Jain Kartikey Yadav Manoj Mohapatra S.V. Godbole B.S. Tomar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,72(5):1122-1126
Time resolved fluorescence spectroscopy (TRFS) of Eu(III) (an analogue of trivalent actinides) complexation with humic acid (HA) and its model compounds, namely phthalic acid (PA), mandelic acid (MA) and succinic acid (SA) has been carried out at varying concentration ratios of ligand to metal ion. The emission spectra were recorded in the range of 550–650 nm by exciting at an appropriate wavelength. The intensity of the 616 nm peak of Eu(III) was found to be sensitive to complexation. The ratio of the intensities of 616 and 592 nm peaks was used to determine the stability constants of Eu-phthalate, Eu-mandelate and Eu-succinate complexes. In the case of model compounds, the life-time was found to increase with increasing ligand to metal ratio (L/M) indicating the decrease in quenching of the fluorescence by coordinated water molecules with increasing complexation. On the other hand in the case of HA, the life-time was found to be constant at least up to L/M of 5, indicating the formation of outer sphere complex. Beyond L/M = 5 the life-time value was found to increase which can be attributed to the binding of the metal ion to the higher affinity sites in the HA macromolecule. 相似文献
104.
Al2O3:Si,Ti, prepared under oxidizing condition at high temperature, gives PL emission around 430 nm when excited with 240 nm. The Al2O3:C, TL/OSL phosphor, also shows emission around 430 nm, which corresponds to characteristic emission of F-center. Thus, to identify the exact nature of luminescent center in Al2O3:Si,Ti, fluorescence lifetime measurement studies were carried out along with the PL,TL and OSL studies. The PL and TL in Al2O3:Si,Ti show emission around 430 nm and the time-resolved fluorescence studies show lifetime of about 43 μs for the 430 nm emission, which is much smaller than the reported lifetime of ∼35 ms for the 430 nm emission (F-center emission) in Al2O3:C phosphor. Therefore, the emission observed in Al2O3:Si,Ti phosphor was assigned to Ti4+ charge transfer transition. Fluorescence studies of Al2O3:Si,Ti do not show any traces of F and F+ centers. Also, Ti4+ does not show any change in the charge state after gamma-irradiation. On the basis of the above studies, a mechanism for TSL/OSL process in Al2O3:Si,Ti is proposed. 相似文献
105.
106.
107.
S.K. Sharma P.K. Pujari K. Sudarshan D. Dutta M. Mahapatra S.V. Godbole O.D. Jayakumar A.K. Tyagi 《Solid State Communications》2009,149(13-14):550-554
We report results on positron annihilation spectroscopic (PAS) studies using lifetime and coincidence Doppler broadening techniques in zinc oxide (ZnO) nanoparticles (4 to 40 nm) synthesized by solid state pyrolytic reaction followed by annealing in the temperature range of 200 °C to 800 °C. Positron lifetime in the nanoparticles are observed to be higher than bulk lifetime in all the cases. Theoretical calculation of lifetime indicates the presence of either Zn or (Zn, O) vacancy clusters which migrate and anneal out at high temperature. Comparison of ratio spectra from coincidence Doppler broadening measurement and calculated electron momentum distribution indicates the presence of either Zn or (Zn, O) vacancies. In addition, photoluminescence (PL) measurements have been carried out to examine the role of defects on the intensity of emission in the visible region. 相似文献
108.
The roll bonding technique is one of the most widely used methods to produce metal laminate sheets. Such sheets offer interesting research opportunities for both scientists and engineers. In this paper, we report on an experimental investigation of the ‘thickness effect’ during laminate rolling for the first time. Using a four-high multifunction rolling mill, Cu/Al/Cu laminate sheets were fabricated with a range of thicknesses (16, 40, 70 and 130 μm) of the Al layer. The thickness of the Cu sheets was a constant 300 μm. After rolling, TEM images show good bonding quality between the Cu and Al layers. However, there are many nanoscale pores in the Al layer. The fraction of nanoscale pores in the Al layer increases with a reduction in the Al layer thickness. The finite element method was used to simulate the Cu/Al/Cu rolling process. The simulation results reveal the effect of the Al layer thickness on the deformation characteristics of the Cu/Al/Cu laminate. Finally, we propose that the size effect of the Al layer thickness during Cu/Al/Cu laminate rolling may offer a method to fabricate ‘nanoporous’ Al sandwich laminate foils. Such foils can be used in electromagnetic shielding of electrical devices and noisy shielding of building. 相似文献
109.
R.M. Godbole S.K. Rai S. Raychaudhuri 《The European Physical Journal C - Particles and Fields》2007,50(4):979-990
The electromagnetic radiation emitted by colliding beams is expected to play an important role at the next generation of high
energy e+e- linear colliders. Focussing on the simplest process, e+e-→μ+μ-, we show that, for suitable machine parameters and luminosity, radiative effects like initial state radiation (ISR) and beamstrahlung
can be used to search for resonant graviton modes of the Randall–Sundrum model in an efficient manner. 相似文献
110.
Sudhansu S. Biswal Debajyoti Choudhury Rohini M. Godbole Ritesh K. Singh 《Pramana》2007,69(5):777-782
We examine, in a model independent way, the sensitivity of a linear collider to the couplings of a light Higgs boson to a
pair of gauge bosons, including the possibility of CP violation. We construct several observables that probe the various possible
anomalous couplings. For an intermediate mass Higgs, a collider operating at a center of mass energy of 500 GeV and with an
integrated luminosity of 500 fb−1 is shown to be able to constrain the ZZH vertex at the few per cent level, with even higher sensitivity for some of the couplings. However, lack of sufficient number
of observables as well as contamination from the ZZH vertex limits the precision to which anomalous part of the WWH coupling can be probed.
相似文献