Results 1 - 10 of 17551
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[en] Nuclei in the vicinity of doubly-magic nucleus "2"0"8Pb with several valence nucleons provide an opportunity to study the interplay between single particle and collective states. Beyond the N = 126 shell closure, nuclear shape changes from spheroidal to mainly quadrupole and octupole deformed shapes. It has been observed that octupole collectivity enhances in comparison to quadrupole collectivity in the nuclei around N = 130. In the present work, preliminary results in the context of "2"1"6Fr have been reported
[en] We demonstrate the first guiding of cold atoms through a 88 mm long piece of photonic band gap fiber. The guiding potential is created by a far-off resonance dipole trap propagating inside the fiber with a hollow core of 12 μm. We load the fiber from a dark spot 85Rb magneto-optical trap and observe a peak flux of more than 105 atoms s-1 at a velocity of 1.5 m s-1. With an additional reservoir optical dipole trap, a constant atomic flux of 1.5 x 104 atoms s-1 is sustained for more than 150 ms. These results open up interesting possibilities to study nonlinear light-matter interaction in a nearly one-dimensional geometry and pave the way for guided matter wave interferometry.
[en] We demonstrate a technique to measure hyperfine structure using a frequency-stabilized diode laser in an acoustic-optic modulator locked to the frequency difference between two hyperfine peaks. We use this technique to measure hyperfine intervals in the 5P3/2 state of 85Rb and obtain a precision of 20 kHz. VNa extract values for the magnetic-dipole coupling constant A = 25.038(5) MHz and the electric-quadrupole coupling constant B 26.011(22) MHz. These values are a. significant improvement over previous results. (authors)
[en] The collapse experiment of a 85Rb Bose-Einstein Condensate [E.A. Donley, et al., Nature 412 (2001) 295] is studied by numerical simulation. We show that the time delay before collapsing observed in the experiment depends not only on the interaction strength parameters but also on the collective motion before being tuned to collapse. We also qualitatively discussed two necessary mechanisms for beyond mean-field theories on collapsing phenomena
[en] The process of Zeeman laser cooling of 85Rb atoms in a new scheme employing a transverse magnetic field has been experimentally studied. Upon cooling, the average velocity of atoms was 12 m/s at a beam intensity of 7.2 x 1012 s-1 and an atomic density of 4.7 x 1010 cm-3
[en] An atomic fountain with 85Rb cold atoms is reported. A series of time-of-flight signals is obtained, and the measured temperature of the cold atomic cloud is about 2.4 μK. It will have potential new applications in the precise measurement of fundamental constants and the proof of the Einstein's equivalence principle. (atomic and molecular physics)
[en] Bisphenol A (BPA) and reactive black 5 (RB5) dye are among the most persistent and non-biodegradable contaminants in water which require an urgent need for the development of effective removal method. The ubiquitous existence of both contaminants could interfere with the human health and aquatic environmental balance. Photocatalytic process as one of advanced oxidation processes (AOPs) has shown high performance for degradation of organic compounds to the harmless materials under sensible condition. Therefore, this study aims to develop a visible-light-driven photocatalyst that can efficiently degrade BPA and RB5 present in household water. N-doped TiO2 were successfully synthesized via simple and direct sol–gel method. The prepared TiO2 nanoparticles were characterized by field emission scanning microscope (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Brunauere Emmette Teller (BET) analysis. The incorporation of nitrogen in TiO2 lattice exhibited excellent optical responses to visible region as revealed by UV–Vis–NIR spectroscopy absorption capability at 400–600 nm. The photocatalytic activity of the N-doped TiO2 nanoparticles was measured by photocatalytic degradation of BPA and RB5 in an aqueous solution under visible-light irradiations. Degradation of BPA and RB5 was 91.3% and 89.1%, respectively after 360 min illumination. The degradation of BPA and RB5 by N-doped TiO2 was increased up to 89.8% and 88.4%, respectively under visible-light irradiation as compared to commercial TiO2 P25. This finding clearly shows that N-doped TiO2 exhibits excellent photocatalytic degradation of BPA and RB5 under visible irradiation, hence have a promising potential in removing various recalcitrant contaminants for water treatment to fulfill the public need to consume clean water. .
[en] In a recent experiment at JILA [E. A. Donley et al., Nature (London) 417, 529 (2002)] an initially pure condensate of 85Rb atoms was exposed to a specially designed time-dependent magnetic-field pulse in the vicinity of a Feshbach resonance. The production of additional components of the gas as well as their oscillatory behavior have been reported. We apply a microscopic theory of the gas to identify these components and determine their physical properties. Our time-dependent studies allow us to explain the observed dynamic evolution of all fractions, and to identify the physical relevance of the pulse shape. Based on ab initio predictions, our theory strongly supports the view that the experiments have produced a molecular condensate
[en] We report on a detailed measurement of the enhanced absorption Hanle effect resonances in 85Rb. The effect was analysed with an experimental setup allowing for the control of each magnetic field component within 1 mG. The characterization deals with the dependence of resonances, observed under different magnetic field conditions, on the frequency, intensity and polarization of the exciting radiation field. An analytic model that precisely describes the resonance behaviour is discussed.