Results 1 - 10 of 1536
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[en] This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.
[en] The eikonal approach is used to carry out numerical calculations of the probability for the passage of relativistic positronium atoms through matter for the purpose of understanding inelastic-screening effects. It is shown that the inclusion of inelastic screening leads to a significant deviation (by several times) of the probability from the simple exponential law which holds when only elastic screening is included. The results that we obtain can be used for planning experiments involving relativistic positronium atoms
[en] We investigate experimentally the route to quasiperiodicity in a driven ratchet for cold atoms and examine the relationship between symmetries and transport while approaching the quasiperiodic limit. Depending on the specific form of driving, quasiperiodicity results in the complete suppression of transport, or in the restoration of the symmetries which hold for a periodic driving
[en] We review different ways to accelerate adiabatic processes in cold atom physics and atomic state preparation. Trap expansions or contractions and atomic transport may be accelerated by an invariant-based inverse engineering approach. Berry's inverse engineering method is also applied to produce fast versions of adiabatic passage methods.
[en] We have synthesized perovskite oxide BaPb1-x Zrx O3 by solid-state reaction in different atmospheres and performed x-ray diffraction (XRD) analyses, electrical resistivity and thermoelectric power measurements on them. Nearly single-phase samples with cubic symmetry were obtained in the range 0.0< x ≤0.25. As x increased, a metal-insulator (MI) transition occurred at a critical doping level xc, which depended on the sintering atmosphere of the samples. Meanwhile, a jump in resistivity was found. At low temperatures (13 K ≤ T ≤ 100 K), the temperature dependence of resistivity followed the power law when 0< x< xc and the hopping law when x≥xc . When prepared in oxygen and in air, the resistivity decreased linearly with the rising temperature in the range between 100 and 300 K. However, the unusual linear behaviour was absent when the doped oxides were sintered in N2. An anomalous broad peak was also observed in the thermoelectric power of the air-sintered samples. The results are discussed in terms of the effects of disorder and electron-electron interactions, oxygen vacancies and the crystal-field splitting of the 4d levels of transition metal Zr. (author)
[en] Various techniques which have been applied to modeling low-energy (much-lt 1 keV) ion-solid interactions on an atomistic scale are described. In addition to their individual strengths, all such methods also have a number of drawbacks, both fundamental and practical. The range of validity, and the problems encountered external to this range, will be outlined for the different approaches. Examples of molecular dynamics simulations of low-energy ion- solid interactions will be presented
[en] Self-trapped carriers of large bipolarons are redistributed among sites of their molecular orbitals in response to atomic motions. This effect lowers the phonon frequencies. The dependence of the zero-point energy on the spatial distribution of large bipolarons produces a phonon-mediated attraction between them. This dynamic quantum-mechanical effect fosters the condensation of large bipolarons into a liquid at sufficiently low temperatures
[en] We report on an efficient and highly controlled cold atom hollow-core fiber interface, suitable for quantum simulation, information, and sensing. The main focus of this manuscript is a detailed study on transporting cold atoms into the fiber using an optical conveyor belt. We discuss how we can precisely control the spatial, thermal, and temporal distribution of the atoms by, e.g., varying the speed at which the atoms are transported or adjusting the depth of the transport potential according to the atomic position. We characterize the transport of atoms to the fiber tip for these different parameters. In particular, we show that by adapting the transport potential we can lower the temperature of the transported atoms by a factor of 6, while reducing the transport efficiency only by a factor 2. We can obtain a transport efficiency into the fiber of about 40% and we study the influence of the different transport parameters on the time-dependent optical depth signal inside the fiber. When comparing our measurements to the results of a classical transport simulation, we find a good qualitative agreement. (paper)
[en] The surface diffusion of individual sulfur atoms on the Ni(111) plane has been investigated by field ion microscopy. The sulfur atoms were segregated to the surface by annealing the tip at 700 K. Surface diffusion on the (111) plane was detected at temperatures above 107 K with an activation energy of 0.29--0.30 eV. These results indicate a very high diffusion rate for sulfur on clean Ni(111) at typical reaction temperatures (e.g., 450--900 K for CO methanation)