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61.
Wiedeking M Tabor SL Pavan J Volya A Aguilar AL Calderin IJ Campbell DB Cluff WT Diffenderfer E Fridmann J Hoffman CR Kemper KW Lee S Riley MA Roeder BT Teal C Tripathi V Wiedenhöver I 《Physical review letters》2005,94(13):132501
Excited states in 20O were populated in the reaction 10Be(14C,alpha) at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and gamma radiation was detected with the FSU gamma detector array. Five new states were observed below 6 MeV from the alpha-gamma and alpha-gamma-gamma coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited 1p-1h excitations across the N=Z=8 shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the p-sd shell gap as neutrons are added. 相似文献
62.
We propose and demonstrate a simple technique for determining the M/# parameter of a holographic recording material. In this method, divergent object and reference beams are used to produce a spatially varying index modulation. One can analyze the resultant diffraction pattern to find M/# by using only a single grating; existing techniques require many gratings. 相似文献
63.
Shahriar MS Tripathi R Kleinschmit M Donoghue J Weathers W Huq M Shen JT 《Optics letters》2003,28(7):525-527
We describe a superparallel holographic optical correlator that performs two-dimensional spatial and angular multiplexing simultaneously. The key step in this architecture is the use of a holographic multiplexer to split a query image into many copies before it applies them to the holographic database. A holographic demultiplexer, in conjunction with an aperture, is used to identify the location and the angle of the brightest correlation peak. This architecture uses only O(square root of N) detector elements to search through N unsorted images in a single query. We demonstrate the basic features of this architecture, using three spatial locations with eight angle-multiplexed images in each location. 相似文献
64.
Alavi-Harati A Alexopoulos T Arenton M Arisaka K Barbosa RF Barker AR Barrio M Bellantoni L Bellavance A Blucher E Bock GJ Bown C Bright S Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Ford R Glazov A Golossanov A Gouffon P Graham J Hamm J Hanagaki K Hsiung YB Huang H Jejer V Jensen DA Kessler R Kobrak HG Kotera K LaDue J Lai N Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Prasad V Qi XR Quinn B Ramberg EJ Ray RE Santos E Senyo K Shanahan P Shields J Slater W Solomey N Swallow EC 《Physical review letters》2003,90(14):141801
The KTeV experiment at Fermilab has isolated a total of 132 events from the rare decay K(L)-->e+ e- mu+ mu-, with an estimated background of 0.8 events. The branching ratio of this mode is determined to be [2.69+/-0.24(stat)+/-0.12(syst)]x10(-9), with a radiative cutoff of M(2)(ee mu mu)/M(2)(K)>0.95. The first measurement using this mode of the parameter alpha from the D'Ambrosio-Isidori-Portolès (DIP) model of the K(L)gamma*gamma* vertex yields a result of -1.59+/-0.37, consistent with values obtained from other decay modes. Because of the limited statistics, no sensitivity is found to the DIP parameter beta. We use this decay mode to set limits on CP and lepton violation. 相似文献
65.
M. K. Pandey R. K. Dubey D. N. Tripathi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):275-279
The Classical Trajectory Monte Carlo (CTMC) Method has
been used to calculate the differential, partial and total single electron
capture cross sections for the collision of H+/D+ with Ca and Mg
atoms in the energy range of 1–100 keV. The differential cross sections
at angles near the diffraction limit (<0.1○) in both systems
show a forward peak followed by an asymptotic fall at higher angles. Total
and partial capture cross sections are found to be in good agreement with
the experimental observations. Oscillations in the partial capture cross sections have been explained due to the swapping
of the field electron.
Isotope effect in the electron transfer is reported to be negligible. 相似文献
66.
We demonstrate theoretically as well as experimentally that a four-layer polymeric waveguide structure can be used to produce a mode and a polarization filter. Various optical properties such as refractive index, birefringence and propagation constant of polycarbonate, polystyrene and a commercially available photoresist (from Shipley) are presented. The thin film structures consisting of glass/polycarbonate/polystyrene/air are used for demonstrating polarization filter action and glass/photoresist/polystyrene/air structure for mode filter. Expressions for the electric field intensity spatial distribution for the structure are used to calculate the intensity profiles to support the observed behavior. The experimental values were in good agreement with the one obtained theoretically. 相似文献
67.
Photoluminescence (PL) properties of swift heavy ions-induced F2 and F3+ color centers in nano-granular lithium fluoride (LiF) thin film were studied. LiF films were deposited on glass and silica substrates and irradiated with various ion species (Ag, Ni and Au) at different irradiation temperatures. The role of ion species, their fluence and the irradiation temperature on the PL intensity of color centers induced in LiF thin films is discussed. 相似文献
68.
69.
70.
Using filament stretching rheometry to predict strand formation and “processability” in adhesives and other non-Newtonian fluids 总被引:1,自引:0,他引:1
The spinning of polymeric fibers, the processing of numerous foodstuffs and the peel and tack characteristics of adhesives
are all associated with the formation, stability and, ultimately, the longevity of thin fluid `strands'. This tendency to
form strands is usually described in terms of the tackiness of the fluid or by heuristic concepts such as `stringiness' (Lakrout
et al. J Adhesion 1999). The dynamics of such processes are complicated due to spatially and temporally non-homogeneous growth
of extensional stresses, the action of capillary forces and the evaporation of volatile solvents. We describe the development
and application of a simple instrument referred to as a microfilament rheometer (MFR) that can be used to readily differentiate
between the dynamical response of different pressure-sensitive adhesive fluid formulations. The device relies on a quantitative
observation of the rate of extensional thinning or `necking' of a thin viscous or viscoelastic fluid filament in which the
solvent is free to evaporate across the free surface. This high-resolution measurement of the radial profile provides a direct
indication of the ultimate time to break up of the fluid filament. This critical time is a sensitive function of the rheological
properties of the fluid and the mass transfer characteristics of the solvent, and can be conveniently reported in terms of
a new dimensionless quantity we refer to as a processability parameter P. We demonstrate the usefulness of this technique by presenting our results in the form of a case study in which we measure
the visco-elasto-capillary thinning of slender liquid filaments for a number of different commercial polymer/solvent formulations
and relate this to the reported processing performance of the materials. We also compare the MFR observations with the prediction
of a simple 1D theory derived from the governing equations that model the capillary thinning of an adhesive filament.
Received: 22 December 1999/Accepted: 4 January 2000 相似文献