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1.
On interpolatory divergence-free wavelets 总被引:1,自引:0,他引:1
We construct interpolating divergence-free multiwavelets based on cubic Hermite splines. We give characterizations of the relevant function spaces and indicate their use for analyzing experimental data of incompressible flow fields. We also show that the standard interpolatory wavelets, based on the Deslauriers-Dubuc interpolatory scheme or on interpolatory splines, cannot be used to construct compactly supported divergence-free interpolatory wavelets.
2.
Using a pump and test beam technique in the frequency domain with pump pulses in the nanosecond time range, the nonlinear transmission properties were investigated at room temperature in photosystem (PS) II membrane fragments and isolated light-harvesting chlorophyll a/b-protein preparations (LHC II preparations). In LHC II preparations and PS II membrane fragments, respectively, pump pulses of 620 nm and 647 nm cause a transmission decrease limited to a wavelength region in the nearest vicinity of the pump pulse wavelength (full width at half maximum ' 0.24 nm). In contrast, at 670 nm neither a transmission decrease nor a narrow band feature were observed. The data obtained for PS II membrane fragments and LHC II preparations at shorter wavelengths (620 nm, 647 nm) were interpreted in terms of excited state absorption of whole pigment-protein clusters within the light-harvesting antenna of photosystem II. The interpretation of the small transmission changes as homogeneously broadened lines led to a transversal relaxation time for chlorophyll in the clusters of about 4 ps. 相似文献
3.
We present a model for conductivity and energy diffusion in a linear chain described by a quadratic Hamiltonian with Gaussian noise. We show that when the correlation matrix is diagonal, the noise-averaged Liouville-von Neumann equation governing the time evolution of the system reduces to the [Lindblad, Commun. Math. Phys. 48, 119 (1976)] equation with Hermitian Lindblad operators. We show that the noise-averaged density matrix for the system expectation values of the energy density and the number density satisfies discrete versions of the heat and diffusion equations. Transport coefficients are given in terms of model Hamiltonian parameters. We discuss conditions on the Hamiltonian under which the noise-averaged expectation value of the total energy remains constant. For chains placed between two heat reservoirs, the gradient of the energy density along the chain is linear. 相似文献
4.
5.
In this paper we consider the essential electronic excited states in parallel chains of semiconducting polymers that are currently being explored for photovoltaic and light-emitting diode applications. In particular, we focus upon various type II donor-acceptor heterojunctions and explore the relation between the exciton binding energy to the band offset in determining the device characteristic of a particular type II heterojunction material. As a general rule, when the exciton binding energy is greater than the band offset at the heterojunction, the exciton will remain the lowest-energy excited state and the junction will make an efficient light-emitting diode. On the other hand, if the offset is greater than the exciton binding energy, either the electron or hole can be transferred from one chain to the other. Here we use a two-band exciton to predict the vibronic absorption and emission spectra of model polymer heterojunctions. Our results underscore the role of vibrational relaxation and suggest that intersystem crossings may play some part in the formation of charge-transfer states following photoexcitation in certain cases. 相似文献
6.
Knez M Sumser MP Bittner AM Wege C Jeske H Hoffmann DM Kuhnke K Kern K 《Langmuir : the ACS journal of surfaces and colloids》2004,20(2):441-447
We studied the adsorption behavior and surface chemistry of the tobacco mosaic virus (TMV) on well-defined metal and insulator surfaces. TMV serves as a tubular supramolecular model system with precisely known surface termination. We show that if the surface chemistry of the substrate and the pH-dependent chemistry of the molecular surface match, for example, by hydrogen bonding, a strong adsorption occurs, and lateral movement is impeded. Due to the immobilization, the virion can be imaged by atomic force microscopy (AFM) in contact mode. We also used self-assembled monolayers with an acyl chloride group to induce covalent bonding via ester formation. Noncontact AFM proved that TMV keeps its cylindrical cross section only under weak adsorption conditions, that is, on hydrophobic surfaces, while on hydrophilic substrates a deformation occurs to maximize the number of interacting chemical groups. 相似文献
7.
Kurt Hiebl Engelbert Tuscher Helmut Bittner 《Monatshefte für Chemie / Chemical Monthly》1979,110(4):869-877
The hydrogen absorption of the phase Ti64Co32–x
Fe
x
(x=0...16) and its influence on the magnetic properties have been investigated. Measurements of the vapour-pressure, wide-line NMR and magnetic susceptibility have been performed. Substitution of Co by Fe does not change the amount of absorbed hydrogen. However the reaction rate of hydriding process, the activation energy of diffusion and the magnetic quantities change upon this substitution. 相似文献
8.
9.
Ibtissam Elaaraj Safae ER. Raouan Asmae Nakkabi Bouchra Es-sounni Ibnsouda Koraichi Noureddine El moualij Mohammed Fahim 《印度化学会志》2022,99(5):100404
New metal complexes of (Zn(II), Co(II), Ni(II) and Cu(II)) based on the ligand 2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzo[d]imidazole] were synthesized, whose structures were determined with the different spectroscopic techniques 1H NMR,13C NMR, FT-IR, UV–Visible and by mass spectrometry. The thermal analysis was performed by TG-DTA. The antioxidant activity of the ligand and its complexes was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) method, in comparison with the synthetic antioxidant, ascorbic acid. The results obtained showed that the antioxidant activity of the ligand and its complexes is moderate and that the copper complex has a high activity that exceeds that of ascorbic acid. Antimicrobial activity of the ligand and its metal complexes was studied against two Gram-positive bacteria: Bacillus subtilis ILP1428B, Staphylococcus aureus CIP543154 and two Gram-negative bacteria: Pseudomonas aeruginosa ATCC27653, Escherichia coli CIP5412 (American Type Culture Collection)the activity data show that the metal complexes are more potent than the free ligand. 相似文献
10.
Electrical and photoelectrical properties of IR-devices manufactured on (Hg, Cd)Te-wafers cut from single crystals grown by modified Bridgman method are reported and compared to those of devices made on THM-(Hg, Cd)Te. MIS-structures and photodiodes were used in order to investigate the different materials. The influence of material parameters and device technology respectively is involved in our discussion of device properties. The quality of modified Bridgman-(Hg, Cd)Te was found to be comparable to that of the THM-(Hg, Cd)Te. At T = 80 K and FOV = 60° background limited detectivity of photodiodes with a cut-off wavelength of λco = 10.7 μm was achieved. 相似文献