Estimation of the hydrodynamic screening length in κ-carrageenan solutions using NMR diffusion measurements

ABSTRACTRe-orientational dynamics of liquid crystal molecules in a polymer network subjected to an electric field is studied by means of light diffraction [1]. When the optical pitch of the electric-field induced cholesteric phase is small compared to the optical wavelength of light, dynamic light scattering (DLS) can be performed to extract the relaxation dynamics of the chiral nematic molecules in the presence of the polymer network. Intriguingly, the reactive mesogenic type of polymer network exhibits a confinement effect, which can be probed within the limited range of scattering angles that comply with the structural correlation length in the system [2].Diffusive mass transport of molecules through a rod network can be studied via fluorescence correlation spectroscopy (FCS) and DLS. Long time self-diffusion of tracer spheres (silica and proteins) in isotropic and nematic colloidal-rod networks (fd-viruses) is systematically studied for various tracer-sphere sizes as compared to the mesh size of the network [3]. In addition, by varying the salt concentration, the relative contribution of electrostatic interactions can be varied. A theory is developed where the diffusion coefficient is expressed in terms of the hydrodynamic screening length of the highly entangled rod-network. The hydrodynamic screening length of rod networks is extracted from diffusion data as a function of the rod concentration both for isotropic and nematic networks [4-5].

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Information and Dose in the Scanning Transmission Ion Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001021 ◽

1980 ◽

Vol 38 ◽

pp. 232-233

Author(s):

Fox T. R. ◽

R. Levi-Setti

Keyword(s):

Information Retrieval ◽

Electron Microscope ◽

Elastic Scattering ◽

Energy Loss ◽

Cross Sections ◽

Previous Analysis ◽

Single Scattering ◽

Screening Length ◽

Relative Damage ◽

Scanning Transmission

At an earlier meeting [1], we discussed information retrieval in the scanning transmission ion microscope (STIM) compared with the electron microscope at the same energy. We treated elastic scattering contrast, using total elastic cross sections; relative damage was estimated from energy loss data. This treatment is valid for “thin” specimens, where the incident particles suffer only single scattering. Since proton cross sections exceed electron cross sections, a given specimen (e.g., 1 μg/cm2 of carbon at 25 keV) may be thin for electrons but “thick” for protons. Therefore, we now extend our previous analysis to include multiple scattering. Our proton results are based on the calculations of Sigmund and Winterbon [2], for 25 keV protons on carbon, using a Thomas-Fermi screened potential with a screening length of 0.0226 nm. The electron results are from Crewe and Groves [3] at 30 keV.

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Deep Impurities with Collision Delay

10.1093/oso/9780198797241.003.0017 ◽

2018 ◽

Author(s):

Klaus Morawetz

Keyword(s):

Wave Function ◽

Kinetic Equation ◽

Elastic Scattering ◽

Response Function ◽

Plasma Oscillation ◽

Impurity Scattering ◽

Fermi Momentum ◽

Screening Length ◽

Plasma Mode ◽

Dissipative Mechanism

The linearised nonlocal kinetic equation is solved analytically for impurity scattering. The resulting response function provides the conductivity, plasma oscillation and Fermi momentum. It is found that virial corrections nearly compensate the wave-function renormalizations rendering the conductivity and plasma mode unchanged. Due to the appearance of the correlated density, the Luttinger theorem does not hold and the screening length is influenced. Explicit results are given for a typical semiconductor. Elastic scattering of electrons by impurities is the simplest but still very interesting dissipative mechanism in semiconductors. Its simplicity follows from the absence of the impurity dynamics, so that individual collisions are described by the motion of an electron in a fixed potential.

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Introducing a Surface-Enhanced-Raman-Scattering Enhancer for Experimental Estimation of the Debye Screening Length in Organic Field-Effect Transistors

ACS Applied Electronic Materials ◽

10.1021/acsaelm.1c00148 ◽

2021 ◽

Author(s):

Hao Li ◽

Cong Wang ◽

Meihua Shou ◽

Yanrui Lin ◽

Xuehua Hou ◽

...

Keyword(s):

Raman Scattering ◽

Field Effect ◽

Field Effect Transistors ◽

Debye Screening Length ◽

Organic Field Effect Transistors ◽

Debye Screening ◽

Screening Length ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering

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Metallocene Polymerization Catalyst Ion-Pair Aggregation by Cryoscopy and Pulsed Field Gradient Spin−Echo NMR Diffusion Measurements

Journal of the American Chemical Society ◽

10.1021/ja0346375 ◽

2003 ◽

Vol 125 (18) ◽

pp. 5256-5257 ◽

Cited By ~ 31

Author(s):

Nicholas G. Stahl ◽

Cristiano Zuccaccia ◽

Tryg R. Jensen ◽

Tobin J. Marks

Keyword(s):

Field Gradient ◽

Spin Echo ◽

Ion Pair ◽

Pulsed Field ◽

Polymerization Catalyst ◽

Nmr Diffusion

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Hydrodynamic screening and axisymmetric turbulence in the transient sedimentation of a dilute suspension at small Reynolds number

Physica A Statistical Mechanics and its Applications ◽

10.1016/j.physa.2008.07.005 ◽

2008 ◽

Vol 387 (24) ◽

pp. 5999-6012 ◽

Cited By ~ 3

Author(s):

B.U. Felderhof

Keyword(s):

Reynolds Number ◽

Small Reynolds Number ◽

Hydrodynamic Screening ◽

Dilute Suspension

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On the Appearance of a Cooper Minimum in the Photoionization Cross Sections of the Plasma-Embedded Li Atom

Research Letters in Physics ◽

10.1155/2009/832413 ◽

2009 ◽

Vol 2009 ◽

pp. 1-5 ◽

Cited By ~ 12

Author(s):

Satyabrata Sahoo ◽

Y. K. Ho

Keyword(s):

Cross Sections ◽

Ground State ◽

Debye Screening Length ◽

Debye Screening ◽

Screening Length ◽

Screening Effect ◽

Plasma Environment ◽

Plasma Screening ◽

Debye Plasma

The plasma screening effect is found to uncover a Cooper minimum in the photoionization cross sections from the ground state of the Li atom embedded in Debye plasma environment. The variation of the location of this minimum with Debye screening length is discussed and analyzed in terms of the instability of the ground state.

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