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131.
Transmission electron microscopy studies of femtosecond laser induced modifications in quartz 总被引:1,自引:0,他引:1
T. Gorelik M. Will S. Nolte A. Tuennermann U. Glatzel 《Applied Physics A: Materials Science & Processing》2003,76(3):309-311
Cross-sectional transmission electron microscopy investigations of femtosecond laser induced sub-micrometer structural modifications
inside crystalline quartz were carried out. Modifications from single laser shots and from lines built of overlapping shots
were imaged. Both single laser shot modifications and line structures show an amorphous core surrounded by a disturbed crystalline
structure. A strong strain field surrounding the central, irradiated, core is responsible for an increase of the refractive
index. Finite element method calculations of the strain field show maxima on both sides of the irradiated core, which are
in good agreement with optical measurements of the refractive-index change.
Received: 29 September 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +49-3641/947792, E-mail: tatiana.gorelik@rz.uni-jena.de 相似文献
132.
Vos MR Jardĺ GE Pallas AL Breurken M van Asselen OL Bomans PH Leclère PE Frederik PM Nolte RJ Sommerdijk NA 《Journal of the American Chemical Society》2005,127(48):16768-16769
Here we present a surfactant molecule (1) containing an ammonium headgroup, in which a bis-ureido group is incorporated in its hydrocarbon chain. Due to strong hydrogen bonding interactions, 1 forms well-defined highly ordered ribbon-like aggregates in water. Moreover, we demonstrate that these ribbons can be functionalized via a modular approach through molecular recognition of other bis-urea containing molecules. The dye disperse orange and biotin were coupled to matching bis-ureido groups and incorporated into the ribbon structure. The anchoring of different functionalities in a modular approach proved to be possible using the molecular recognition capabilities of the bis-ureido moiety, thereby opening possibilities to a wide range of applications. 相似文献
133.
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135.
K. Kayser W. Collin P. Filss S. Guldbakke G. Nolte H. Reich J. O. Trier W. Witschel 《Zeitschrift für Physik A Hadrons and Nuclei》1970,239(5):447-460
In order to obtain data on the photon absorption process between the giant resonance and the meson threshold the cross sections of the reactions12C(γ,n)11C,12C(γ, 2n)10C,39K(γ,n)38Kg, and40Ca(γ,np)38Kg have been determined by the analysis of yield curves at the 140 MeV electron synchrotron of the PTB. Though the (γ,n) cross sections grow small with increasing photon energy they are different from zero up to energies of 60 MeV and above. The cross section of the reaction12C(γ, 2n) is extremely small; its highest value amounts to 0.15% of the highest value of the12C(γ,n) reaction. The measured40Ca(γ,np) cross section is of the order predicted by the naive quasi-deuteron model. The integrated cross sections of the above reactions up to 140MeV are 85±7,0.90±0.10, 139±16, and 76±7MeVmb respectively. 相似文献
136.
Lensen MC Takazawa K Elemans JA Jeukens CR Christianen PC Maan JC Rowan AE Nolte RJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(4):831-839
The formation of micrometer-sized, highly ordered porphyrin rings on surfaces has been investigated. The porphyrin-based nanoarchitectures are formed by deposition from evaporating solutions through a surface dewetting process which can be tuned by variations in the substitution pattern of the molecules used, the coating of the surface and the conditions under which the evaporation takes place. Control over the combined self-assembly and surface dewetting results in nanorings possessing a defined internal architecture. The ordering of the molecules within the rings has been studied by a variety of microscopy techniques (TEM, AFM, fluorescence microscopy) and the exact ordering of the porphyrins within the rings has been quantified. 相似文献
137.
138.
The synthesis and conformational behavior of two cyclodextrin dimers containing aromatic bipyridine spacers is presented. The proton NMR spectra of these dimers in aqueous solution show a doubling of signals in the aromatic region due to complete or partial self-inclusion of the spacer. The degree and the strength of self-inclusion is dependent on the substitution pattern of the bipyridine unit. This unexpected difference in the self-inclusion behavior is revealed by 2D NOESY and circular dichroism spectra. 相似文献
139.
A new type of giant amphiphilic molecule has been synthesized by covalently connecting a lipase enzyme headgroup to a maleimide-functionalized polystyrene tail (40 repeat units). The resulting biohybrid forms catalytic micellar rods in water. 相似文献
140.
Alanyl-alanine-derived poly(isocyanide)s possess a helical structure that persists even in aqueous media. These rigid macromolecules possess a regular distribution of carboxylic acid-terminated side chains which for the first time allows the study of the templating process involved in biomineralization using a shape-persistent polymeric template. It is demonstrated that in the case where the polymer derived from l-Ala-d-Ala is used the formation of apple core-type calcite crystals is controlled both by nucleation of the (01.1) face and subsequent adsorption of the polymer to the {hk.0} faces of the growing crystal. A small change in the secondary structure of the template that is introduced by using the polymer derived from l-Ala-l-Ala is directly reflected in the lower degree of control over the crystallization process. 相似文献