排序方式: 共有29条查询结果,搜索用时 46 毫秒
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Hoeb M Auernhammer M Schoell SJ Brandt MS Garrido JA Stutzmann M Sharp ID 《Langmuir : the ACS journal of surfaces and colloids》2010,26(24):18862-18867
We present an approach for the thermally activated formation of alkene-derived self-assembled monolayers on oxygen-terminated single and polycrystalline diamond surfaces. Chemical modification of the oxygen and hydrogen plasma-treated samples was achieved by heating in 1-octadecene. The resulting layers were characterized using X-ray photoelectron spectroscopy, thermal desorption spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and water contact angle measurements. This investigation reveals that alkenes selectively attach to the oxygen-terminated sites via covalent C-O-C bonds. The hydrophilic oxygen-terminated diamond is rendered strongly hydrophobic following this reaction. The nature of the process limits the organic layer growth to a single monolayer, and FTIR measurements reveal that such monolayers are dense and well ordered. In contrast, hydrogen-terminated diamond sites remain unaffected by this process. This method is thus complementary to the UV-initiated reaction of alkenes with diamond, which exhibits the opposite reactivity contrast. Thermal alkylation increases the range of available diamond functionalization strategies and provides a means of straightforwardly forming single organic layers in order to engineer the surface properties of diamond. 相似文献
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Molar extinction coefficients of some carbohydrates viz. l-arabinose (C5H10O5), d-glucose (C6H12O6), d-mannose (C6H12O6), d-galactose (C6H12O6), d(-) fructose (C6H12O6) and maltose (C12H24O12) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by gamma ray transmission method in a
narrow beam good geometry set-up. These coefficients have been found to depend upon the photon energy following a 4-parameter
polynomial. These extinction coefficients for different sugars having the same molecular formula have same values varying
within experimental uncertainty. Within concentration ranges studied, Beer-Lambert law is obeyed very well. 相似文献
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Lijuan Zhang Michael Kappl Günter K. Auernhammer Beate Ullrich Hans-Jürgen Butt et al. 《Applied physics. B, Lasers and optics》1991,52(4):A6-A6
X-Ray spectra and chemical binding 相似文献
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Dominique Collin Günter K. Auernhammer Odile Gavat Philippe Martinoty Helmut R. Brand 《Macromolecular rapid communications》2003,24(12):737-741
We describe the preparation and characterization of uniaxial magnetic gels. Fibril formation of the embedded magnetic particles generates easily detectable magnetic and optical anisotropies. A finite magnetization is frozen‐in and leads to a ferromagnetic‐like response in small homogeneous external magnetic fields. We present, for the first time, frequency dependent measurements of the shear modulus G′. Despite their optical and magnetic anisotropy, the gels are mechanically isotropic.
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D. Auernhammer M. Schmitt M. Ohtsuka M. Kohl 《The European physical journal. Special topics》2008,158(1):249-254
The technologies of electron beam lithography, dry
etching and systems integration are investigated to fabricate a series of
Ni-Mn-Ga double-beam structures designed with decreasing critical dimensions
of 10 μm, 1 μm and 400 nm. Ni-Mn-Ga thin films of 1 μm
thickness are deposited by magnetron sputtering and heat-treated in
free-standing condition after selective removal of the substrate.
Differential scanning calorimetry and electrical resistance measurements on
the films show the characteristic features of martensitic transformation
above room temperature. First optical beam deflection experiments
demonstrate the magnetic and thermal actuation performance of the
double-beam structures. 相似文献
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The structure of 1,3-dehydro-5-adamantyl cation and its isoelectronic boron analogue 1,3-dehydro-5-boraadamantane as well as some related adamantane systems, hitherto unknown as persistent long-lived species, were investigated by using the density functional theory (DFT) method. (13)C and (11)B NMR chemical shifts of the compounds were also calculated using the IGLO method. Stabilization of the systems due to homoconjugation is discussed. 相似文献
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GK Johri Akhilesh Tiwari Saumya Saxena Rajesh Sharma Kuldeep Srivastava Manoj Johri 《Pramana》2002,58(3):563-567
Calculations for the relative width (Δω/ω0) as a function of refractive index and relative radius of the photonic band gap for the fcc closed packed 3-D dielectric
microstructure are reported and comparison of experimental observations and theoretical predictions are given. This work is
useful for the understanding of photonic crystals and occurrence of the photonic band gap. 相似文献
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Daniela Fell Mordechai Sokuler Andreas Lembach Thomas F. Eibach Chuanjun Liu Elmar Bonaccurso Günter K. Auernhammer Hans-Jürgen Butt 《Colloid and polymer science》2013,291(8):1963-1976
Drops impacting on horizontal aqueous surfactant films have been analyzed using a high-speed camera. Drops of either water or aqueous surfactant solutions had a diameter of 2.4?±?0.4 mm and impacted with a velocity of 0.1 to 1.3 m/s. As surfactants, anionic sodium dodecyl sulfate and cationic cetyltrimethyl ammonium bromide were used. Pure water drops impacting on freestanding surfactant films showed coalescence, bouncing, partial bouncing, passing, and partial passing. For bouncing, the concentration of surfactant in the surfactant film must exceed the critical micelle concentration. When surfactant was added to the drop, coalescence and partial passing were suppressed. We attribute the different behavior to different hydrodynamic boundary conditions at the surface of pure water and surfactant solution, leading to different repulsive hydrodynamic forces arising when the air has to flow out of the closing gap between the two liquid surfaces. The boundary condition changes as a function of surfactant concentration from a slip to no-slip, leading to stronger hydrodynamic repulsion. In addition, estimates of the characteristic velocities show that diffusion of air into the water is slow and can only account for the very last thinning of the air gap before coalescence. 相似文献
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