نتایج جستجو برای: ionization constant

تعداد نتایج: 255152  

Journal: :Journal of Research of the National Bureau of Standards 1952

Journal: :Biomacromolecules 2009
Pei Lian Ma Marc Lavertu Françoise M Winnik Michael D Buschmann

The interaction of chitosan with plasmid DNA was investigated as a function of pH, buffer composition, degree of deacetylation (DDA), and molecular weight (M(n)) of chitosan, using isothermal titration microcalorimetry (ITC). The Single Set of Identical Sites model was used to obtain the enthalpy of interaction, the binding constant, and the stoichiometry of binding. The chitosan-DNA interactio...

Journal: :Physical chemistry chemical physics : PCCP 2011
Scott T Sullivan Wade G Rellergert Svetlana Kotochigova Kuang Chen Steven J Schowalter Eric R Hudson

The formation of (40)Ca(2)(+) molecular ions is observed in a hybrid (40)Ca magneto-optical and ion trap system. The molecular ion formation process is determined to be photo-associative ionization of ultracold (40)Ca atoms. A lower bound for the two-body rate constant is found to be beta ≥ 2 ± 1 × 10(-15) cm(3) Hz. Ab initio molecular potential curves are calculated for the neutral Ca(2) and i...

Journal: :Medical physics 2004
S Amerio A Boriano F Bourhaleb R Cirio M Donetti A Fidanzio E Garelli S Giordanengo E Madon F Marchetto U Nastasi C Peroni A Piermattei C J Sanz Freire A Sardo E Trevisiol

A pixel-segmented ionization chamber has been designed and built by Torino University and INFN. The detector features a 24 x 24 cm2 active area divided in 1024 independent cylindrical ionization chambers and can be read out in 500 micros without introducing dead time; the digital charge quantum can be adjusted between 100 fC and 800 fC. The sensitive volume of each single ionization chamber is ...

2009
A. I. Mikhailov A. V. Nefiodov G. Plunien

The single ionization of inner-shell electrons by electron or positron impact are the fundamental processes, which still attract considerable interest in collision theory, experimental studies, and various applications. To predict the ionization cross sections, one usually employs either sophisticated numerical approaches or empirical and semiempirical formulas. Significant efforts have been al...

2010
Zhongmin Xiong Mark J Kushner

Multi-atmospheric pressure, pulsed electric discharge excited lasers require pre-ionization to produce spatially uniform glows. Many such systems use corona bars to produce ultraviolet (UV) and vacuum ultraviolet (VUV) light as photo-ionization sources for this purpose. Corona bars are transient surface discharges, typically in a cylindrical geometry, that sustain high electron temperatures and...

Journal: :Physical review letters 2012
J C Berengut V A Dzuba V V Flambaum A Ong

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, α. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(...

Journal: :Physical review letters 2011
J K Wahlstrand Y-H Cheng Y-H Chen H M Milchberg

We directly measure the nonlinear optical response in argon and nitrogen in a thin gas target to laser intensities near the ionization threshold. No instantaneous negative nonlinear refractive index is observed, nor is saturation, in contrast with a previous measurement [Opt. Express 17, 13429 (2009)] and calculations [Phys. Rev. Lett. 106, 183902 (2011)]. In addition, we are able to cleanly se...

1996
Klaus Ergenzinger

A new semiclassical approach to ionization by an oscillating field is presented. For a δ–function atom, an asymptotic analysis is performed with respect to a quantity h, defined as the ratio of photon energy to ponderomotive energy. This h appears formally equivalent to Planck’s constant in a suitably transformed Schrödinger equation and allows semiclassical methods to be applicable. Systematic...

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