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21.
Surface induced local d-band states in the upper 4d band between ~ 4 and ~ 5.2 eV below EFermi have been identified for polycrystalline silver films in photoemission experiments using synchroton radiation. A thin over-coat (10 å) by an Al film leads to a depression of these surface induced local states whereas a change from s- to p-polarized excitation leads to an enhancement. Deposition of additional silver (~ 3 Å) at 120 K induces additional emission 4.2 eV below EF with a FWHM of only ~ 0.4 eV. 相似文献
22.
Bo Jakobsen Kristine Niss Claudio Maggi Niels Boye Olsen Tage Christensen Jeppe C. Dyre 《Journal of Non》2011,357(2):267-273
The phenomenology of the beta relaxation process in the shear-mechanical response of glass-forming liquids is summarized and compared to that of the dielectric beta process. Furthermore, we discuss how to model the observations by means of standard viscoelastic modeling elements. Necessary physical requirements to such a model are outlined, and it is argued that physically relevant models must be additive in the shear compliance of the alpha and beta parts. A model based on these considerations is proposed and fitted to data for Polyisobutylene 680. 相似文献
23.
Tage Christensen Bo Jakobsen Jon Papini Tina Hecksher Jeppe C. Dyre Niels Boye Olsen 《Journal of Non》2011,357(2):346-350
In order to describe relaxation the thermodynamic coefficient can be generalized into a complex frequency-dependent cross response function. We explore theoretically the possibility of measuring for a supercooled liquid near the glass transition. This is done by placing a thermistor in the middle of the liquid which itself is contained in a spherical piezoelectric shell. The piezoelectric voltage response to a thermal power generated in the thermistor is found to be proportional to but factors pertaining to heat diffusion and adiabatic compressibility κS(ω) do also intervene. We estimate a measurable piezoelectric voltage of 1 mV to be generated at 1 Hz for a heating power of 0.3 mW. Together with κS(ω) and the longitudinal specific heat cl(ω) which may also be found in the same setup a complete triple of thermoviscoelastic response functions may be determined when supplemented with shear modulus data. 相似文献
24.
This paper summarizes the properties of strongly correlating liquids, i.e., liquids for which the virial/potential energy correlation coefficient is above 0.9 for equilibrium fluctuations in the NVT ensemble. The definition and properties of strongly correlating liquids' isomorphs are given, and various isomorph invariants are discussed. The cause of strong virial/potential energy correlations is also discussed, and it is argued that strongly correlating liquids are not merely to be thought of as approximate inverse power-law liquids. The experimental predictions for strongly correlating glass-forming liquids include: i) density scaling; ii) isochronal superposition; iii) that there is a single function of frequency from which all frequency-dependent viscoelastic response functions may be calculated; iv) that strongly correlating liquids are approximately single-parameter liquids with close to unity Prigogine-Defay ratio; v) that the fictive temperature initially decreases for an isobaric temperature up jump. The paper also briefly discusses the “isomorph filter”, which provides a necessary condition for universality of theories for the non-Arrhenius temperature dependence of the relaxation time. 相似文献
25.
Jeppe Byskov-Nielsen Juha-Matti Savolainen Martin Snogdahl Christensen Peter Balling 《Applied Physics A: Materials Science & Processing》2010,98(1):97-101
In this paper we present femtosecond laser ablation studies of the metals copper, silver and tungsten. Measurements of the
threshold fluence determined from the hole diameters versus fluence provide incubation coefficients of the three materials,
which are found to be equal within one standard deviation. Furthermore, we have determined the single-shot threshold fluences
to be 1.7±0.3 J/cm2, 1.5±0.4 J/cm2 and 0.44±0.02 J/cm2 for copper, silver and tungsten, respectively. These are in good agreement with theoretical values calculated neglecting
heat diffusion. 相似文献
26.
The Structure of the Cobalt Oxide/Au Catalyst Interface in Electrochemical Water Splitting 下载免费PDF全文
27.
A CE procedure was established for the nondenaturing separation and identification of the isoforms of the actin-binding human plasma protein Gc-globulin. To characterize interactions with globular actin (G-actin), a novel method was developed for the simultaneous qualitative assessment of the binding interaction between the three major isoforms of Gc-globulin and G-actin using pre-equilibrium affinity CE and UV detection. Evidence was found that some difference in binding affinity existed among the isoforms, although the quantification of this difference was not feasible by UV detection because of the high affinity nature of the binding. The difference in affinity appeared to be related to the pI of the isoforms; a high pI corresponding to a high affinity. For quantitative binding studies Gc-globulin was fluorescently labeled with 5-(and-6)-carboxyfluorescein, succinimidyl ester (CFSE). Data suggested that extensive labeling interfered with actin binding but with moderately labeled Gc-globulin it was possible to determine a dissociation constant of K(d) = 21 +/- 1 nM for the binding between labeled Gc-globulin and G-actin using pre-equilibrium affinity CE and LIF detection. 相似文献
28.
Jeppe?FockEmail author Lara?Katrina?Bogart Oliver?Posth Mikkel?Fougt?Hansen Quentin?A.?Pankhurst Cathrine?Frandsen 《Hyperfine Interactions》2016,237(1):23
The magnetite/maghemite content within iron oxide nanoparticles can be determined using the mean isomer shift (\(\overline {\delta }\)). However, accurate characterisation of the composition is limited by the uncertainty associated with \(\overline {\delta }\). We have identified four independent sources of uncertainty and developed a quantitative expression for the uncertainty budget. Sources of uncertainty are categorised as follows: that from the fitting of the Mössbauer spectrum (σ fit), that of the calibration of the α-Fe reference spectrum (σ cal), thermal corrections to the spectrum due to second order Doppler shift (SODS) (σ Δδ ) and other experimental errors (σ err). Each contribution is discussed in detail using 57Fe Mössbauer spectra obtained from an iron oxide nanoparticle system at temperatures between 16 K and 295 K on different spectrometers in two different laboratories. 相似文献
29.
We present a robust linear-scaling algorithm to compute the symmetric square-root or Lowdin decomposition of the atomic-orbital overlap matrix. The method is based on Newton-Schulz iterations with a new approach to starting matrices. Calculations on 12 chemically and structurally diverse molecules demonstrate the efficiency and reliability of the method. Furthermore, the calculations show that linear scaling is achieved. 相似文献
30.