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The phenomena of electric field-assisted inelastic Bloch-electron scattering from an atomically confined bound-state electron is reported. A novel formalism for treating Bloch electron dynamics and quantum transport in electric fields of arbitrary strength and time dependence is utilized. The two-electron inelastic scattering rate obtained herein shows an electric field-dependent broadening; as a novel addition, the calculated scattering rate includes an explicit dependence on band structure, predicting a strong influence from band non-parabolicity and anisotropy. 相似文献
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Ira Assent Ralph Krieger Boris Glavic Thomas Seidl 《Knowledge and Information Systems》2008,16(1):29-51
Many environmental, scientific, technical or medical database applications require effective and efficient mining of time
series, sequences or trajectories of measurements taken at different time points and positions forming large temporal or spatial
databases. Particularly the analysis of concurrent and multidimensional sequences poses new challenges in finding clusters
of arbitrary length and varying number of attributes. We present a novel algorithm capable of finding parallel clusters in
different subspaces and demonstrate our results for temporal and spatial applications. Our analysis of structural quality
parameters in rivers is successfully used by hydrologists to develop measures for river quality improvements.
相似文献
Thomas SeidlEmail: |
998.
Krieger E Nielsen JE Spronk CA Vriend G 《Journal of molecular graphics & modelling》2006,25(4):481-486
pK(a) calculations for macromolecules are normally performed by solving the Poisson-Boltzmann equation, accounting for the different dielectric constants of solvent and solute, as well as the ionic strength. Despite the large number of successful applications, there are some situations where the current algorithms are not suitable: (1) large scale, high-throughput analysis which requires calculations to be completed within a fraction of a second, e.g. when permanently monitoring pK(a) shifts during a molecular dynamics simulation; (2) prediction of pK(a)s in periodic boundaries, e.g. when reconstructing entire protein crystal unit cells from PDB files, including the correct protonation patterns at experimental pH. Such in silico crystals are needed by 'self-parameterizing' molecular dynamics force fields like YASARA YAMBER, that optimize their parameters while energy-minimizing high-resolution protein crystals. To address both problems, we define an empirical equation that expresses the pK(a) as a function of electrostatic potential, hydrogen bonds and accessible surface area. The electrostatic potential is evaluated by Ewald summation, which captures periodic crystal environments and the uncertainty in atom positions using Gaussian charge densities. The empirical proportionality constants are derived from 217 experimentally determined pK(a)s, and despite its simplicity, this pK(a) calculation method reaches a high overall jack-knifed accuracy, and is fast enough to be used during a molecular dynamics simulation. A reliable null-model to judge pK(a) prediction accuracies is also presented. 相似文献
999.
J Bhawan RW Bain DT Purtilo N Gomez C Dewan CF Whelan SM Dolorum L Edelstein 《Canadian Metallurgical Quarterly》1976,3(1):5-16
A 73-year-old woman from Guyana had nodular keloidal lesions on her face which had persisted for 56 years. A biopsy of the lesion revealed lobomycosis, a rare fungal infection. Microscopically, numerous fungi were seen in giant cells and macrophages. The macrophages had abundant pink reticulated cytoplasm. These macrophages in lobomycosis, considered by some in the past to be granular myoblastoma cells, were rich in glycoproteins and appeared to be "Gaucher-like cells" in electronmicrographs. Further, a transition of macrophages containing organisms to Gaucher-like cells was noted. Antibodies to the fungus were demonstrated in the patient's serum by counter immunoelectrophoresis and indirect immunofluorescence studies. We postulate that the Gaucher-like cells formed because of the inability of host macrophages to digest glycoproteins in the capsule of this unusual fungus. 相似文献
1000.
The pyrolysis of organic waste polymers to produce fuels and chemicals is of interest to augment petroleum-based processes. The wide variety of pyrolysis products of low yield and the uncertain role that heat transfer rate plays in determining these have been deterrents to utilization in the past. A possible approach to increased selectivity for products is to heat them rapidly and homogeneously with the aim of narrowing the product distribution. A very rapid means of homogeneous heat transfer throughout the substrate is microwave heating. A laboratory study has been done to determine what effect high-intensity microwave energy has on the thermal degradative pathways of cellulose. The product distribution found when cellulose is pyrolyzed in the absence of a microwave discharge is similar to that found in conventional furnace pyrolysis. The major products are levoglucosan (27%), carbon dioxide (2–5%), water, and charred residue. However, the total heat-up and reaction times for even large pellets are reduced to less than 2–3 min when high-intensity microwave irradiation is employed. Effects of pressure and microwave power are reported. Low external gas temperature also prevents secondary reactions. 相似文献