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121.
S. P. L. Sörensen und A. C. Andersen 《Fresenius' Journal of Analytical Chemistry》1906,45(3-4):217-231
Ohne Zusammenfassung 相似文献
122.
Chemisorption of 1,1-dichloroethene (Cl2CCH2) to a Si(1 1 1)-7 × 7 surface was studied by means of X-ray photoelectron spectroscopy using synchrotron radiation, recording chlorine 2p and carbon 1s spectra. For carbon 1s, spectral assignment of the chemisorbed species is based on quantum chemical calculations of chemical shifts in model compounds.The results confirm the identity of covalently bonded 1-chlorovinyl (-CClCH2) and vinylidene (CCH2) adspecies. Upon chemisorption at room temperature it was found that about one-third of the molecules break one C-Cl bond while about two-thirds of the adsorbates break two C-Cl bonds. We do not, however, find evidence for isomerization of CCH2 to di-bonded vinylene (-CHCH-). 相似文献
123.
Equivalent drag-reducing performance is observed with 3 M riblets in fully developed internal (pipe) and developing external (flat plate) flows. Drag reduction begins around h
+ = 3, peaks between 6 and 9% at about h
+ = 12, and becomes zero for a value of h
+ between 20 and 30. In laminar pipe flow no significant change in drag is observed with the 3 M riblets present. At high Reynolds numbers, after exhibiting fully rough behaviour, friction factors for the 3 M riblets are observed to monotonically decrease with increasing Reynolds number. 相似文献
124.
Graphitic‐Carbon Layers on Oxides: Toward Stable Heterogeneous Catalysts for Biomass Conversion Reactions
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Dr. Haifeng Xiong Thomas J. Schwartz Nalin I. Andersen Prof. James A. Dumesic Prof. Abhaya K. Datye 《Angewandte Chemie (International ed. in English)》2015,54(27):7939-7943
Conversion of biomass‐derived molecules involves catalytic reactions under harsh conditions in the liquid phase (e.g., temperatures of 250 °C and possibly under either acidic or basic conditions). Conventional oxide‐supported catalysts undergo pore structure collapse and surface area reduction leading to deactivation under these conditions. Here we demonstrate an approach to deposit graphitic carbon to protect the oxide surface. The heterogeneous catalysts supported on the graphitic carbon/oxide composite exhibit excellent stability (even under acidic conditions) for biomass conversion reactions. 相似文献
125.
126.
Surface-dependent chemical equilibrium constants and capacitances for bare and 3-cyanopropyldimethylchlorosilane coated silica nanochannels 总被引:1,自引:0,他引:1
Andersen MB Frey J Pennathur S Bruus H 《Journal of colloid and interface science》2011,353(1):301-310
We present a combined theoretical and experimental analysis of the solid-liquid interface of fused-silica nanofabricated channels with and without a hydrophilic 3-cyanopropyldimethylchlorosilane (cyanosilane) coating. We develop a model that relaxes the assumption that the surface parameters C(1), C(2), and pK(+) are constant and independent of surface composition. Our theoretical model consists of three parts: (i) a chemical equilibrium model of the bare or coated wall, (ii) a chemical equilibrium model of the buffered bulk electrolyte, and (iii) a self-consistent Gouy-Chapman-Stern triple-layer model of the electrochemical double layer coupling these two equilibrium models. To validate our model, we used both pH-sensitive dye-based capillary filling experiments as well as electro-osmotic current-monitoring measurements. Using our model we predict the dependence of ζ potential, surface charge density, and capillary filling length ratio on ionic strength for different surface compositions, which can be difficult to achieve otherwise. 相似文献
127.
Experiments are performed on glass/polyester composites under fatigue loading. The stiffness degradation is recorded as an indirect measure of material damage. The stiffness decrease rate is described by a power dependence on stress; this relationship allows the fatigue law to be derived. Stiffness-controlled fatigue curves are generated and presented in an S-N-diagram based on normalized stress (equivalent to strain). Such stiffness controlled fatigue curves can be used as a basis for design criteria for components.Presented at the 9th International Conference on Mechanics of Composite Materials, 17–20 October 1995, Riga, Latvia.Materials Department, Risø National Laboratory, Roskilde, Denmark. Published in Mekhanika Kompozitnykh Materialov, Vol. 32, No. 1, pp. 32–41, January–February, 1996. 相似文献
128.
L.H. Andersen A. Lapierre S.B. Nielsen I.B. Nielsen S.U. Pedersen U.V. Pedersen S. Tomita 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(3):597-600
Absorption of gas-phase biomolecules has been studied at the heavy-ion storage ring ELISA. Here we discuss the absorption
characteristics of the chromophores of the Green Fluorescent Protein (GFP). The gas-phase absorption maximum of the deprotonated
chromophore (anion form) is at 479 nm. This is almost identical to one of the two absorption maxima of the protein, being
at 477 nm, which is ascribed to a deprotonated chromophore in the protein. The protonated chromophore (cation form) has a
maximum at 406 nm in the gas phase. We compare the gas-phase results with absorption profiles of GFP and chromophores in liquids,
and argue that the absorption characteristics of GFP are mainly ascribed to intrinsic chemical properties of the chromophore.
Evidently, the special β-can structure of GFP provides shielding of the chromophore from the surroundings without significantly
changing the electronic structure of the chromophore through interactions with amino acid side chains.
Received 28 December 2001 Published online 13 September 2002 相似文献
129.
Inventiones mathematicae - 相似文献
130.
B. Concina S. Tomita J. U. Andersen P. Hvelplund 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):191-194
A delayed ionisation experiment has been carried out on laser excited C70 molecules. Ions and electrons are detected in coincidence to distinguish the ionisation of C70 from that of C68 molecules created by the dominant process, emission of C2. From the time dependence of the C70+ yield and the ratio to the C68+ yield, we can deduce both the dissociation energy, Ed = 9.7 ±0.3 eV, and the pre–exponential factor, Ad = 1.7 ×1020 s-1, in the Arrhenius decay law for C2 emission. The power of photon emission from neutral C70 is also determined. 相似文献