Materials Literature
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Silver and gold nanorods with aspect ratios from 1 to 16 have been used as substrates for surface enhanced Raman spectroscopy (SERS) in colloidal solution. The nanorod aspect ratio is varied to give different degrees of overlap between the nanorod longitudinal plasmon band and excitation source in order to determine i…
Magic-sized cadmium selenide (CdSe) nanocrystals have been pyrolytically synthesized. These ultra-small nanocrystals exhibit broadband emission (420-710 nm) that covers most of the visible spectrum while not suffering from self absorption. This behavior is a direct result of the extremely narrow size distribution and…
Mit Dreh: Beim Mischen von Oligosilanen mit Polysacchariden wie Amylose und Schizophyllan entstehen neuartige Einschlussverbindungen (siehe Bild). Die Oligosilangäste nehmen eine helicale Konformation im Innern der chiralen Kanäle ein, die von der links- oder rechtsgängigen helicalen Hülle des polymeren Polysaccharidw…
Abstract Summary: A new poly(fluorene‐ co ‐carbazole) (PFC‐1) with a large substituent group (ADN, a naphthalene‐anthracene derivative moiety) at the 9‐position of carbazole was synthesized. Compared with poly(fluorene‐ co ‐carbazole)s that have an alkyl substituent group at the 9‐position of the carbazole, the UV‐vis…
Abstract Summary: Concurrent tandem catalysis systems have shown a significant advantage in the convenient synthesis of linear low‐density polyethylene (LLDPE) from a sole ethylene monomer stock by uniquely coupling the tandem action between an ethylene oligomerization catalyst and an ethylene copolymerization catalys…
Abstract Summary: The fragmentation of supports, a key issue for the polymerization of olefins via supported metallocene catalysts, was investigated by laser scanning confocal fluorescence microscopy (LSCFM). Metallocenes were immobilized on silica and on two organic supports, namely polystyrene latex particles and a…
Using the field emission effect of a carbon nanotube (CNT), we characterized a new type of technology for detecting low pressure. The fabricated low pressure sensor is of a triode type, consisting of a cathode (carbon nanotubes field emitter arrays), a grid, and a collector. The gauge described here has a triode confi…
Abstract Star‐shaped poly( L ‐lactide)s (PLAs) bearing variable numbers of secondary hydroxyl groups at linear arms chain‐ends and primary hydroxyl groups directly attached to dipentaerithritol core (DPE) ((HO) 6 − x DPE(PLA‐OH) x , where x = 1–6) were prepared and then analyzed by means of size exclusion chromatograp…
The phonons of single-wall carbon nanotubes are investigated within a generalized bond-charge model. The computed phonon dispersions generally agree with earlier results: two acoustic phonons (longitudinal and rotating), flexure modes at low frequencies, and radius-dependent radial breathing modes. Computation of the…
The sputtering yields of tungsten and tantalum due to low-energy (30–125eV) xenon ion bombardment in a plasma environment are measured both using weight loss and spectroscopic techniques. The yields of both tungsten and tantalum are practically identical and show a reduction of 3 when compared to the molybdenum yield…
Abstract 3D dandelion‐like porous nanostructures and 2D nanowalls of copper phosphate dihydrate built up of thin nanosheets have been synthesized simply by corrosion of a copper foil with aqueous phosphoric acid under mild conditions. The composition of the nanostructures has been confirmed by XRD, ICP‐AES, and Raman…
Abstract This article describes the polyaddition of bifunctional five‐membered cyclic carbonates and diethylenetriamine. The polyaddition proceeded via the selective addition of the primary amino group to the cyclic carbonates to give poly(hydroxyurethane)s bearing a secondary amine structure in the main chain. The re…
Perovskite oxide La 0.825 Sr 0.175 MnO 3 (LSMO) nanowires are synthesized using the anodized alumina oxide template technique and the characterization of the microstructure, magnetic and photoluminescence properties is performed. The as-prepared LSMO nanowires 50 nm in diameter and tens of microns in length exhibit po…
We address in this paper the long debated issue of the possibility of vibrational pumping under Surface Enhanced Raman Scattering (SERS) conditions, both theoretically and experimentally. We revisit with simple theoretical models the mechanisms of vibrational pumping and its relation to heating. This presentation prov…
The formation of singlet oxygen due to the energy transfer from excitons confined in silicon nanocrystals to oxygen molecules is studied using time-resolved photoluminescence spectroscopy. The process of the excitation of oxygen molecules from the ground triplet state to the second excited singlet state is studied at…
Abstract Summary: Octamaleimidophenyl polyhedral oligomeric silsesquioxane (OmipPOSS) was synthesized via the imidization reaction between octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) and maleic anhydride, and it was characterized by means of Fourier transform infrared (FTIR) and NMR spectroscopies.…
The effects of cross-sectional deformation and bending on the electronic structures of single-wall carbon nanotubes (SWNTs) are examined. Upon increasing the deformation, semiconducting SWNTs undergo semiconductor-metal transition, and the conduction band and valence band show asymmetric response to the deformation. T…
Abstract Summary: A scaling exponent to describe the dependence of the hydrodynamic radius as a characteristic length of the molecule on the molecular weight, has been determined for low generation dendrimers with a thiacalixarene core and lysine dendrons. The hydrodynamic radius has been calculated from the diffusion…
Unter Strom: Die strukturellen und elektronischen Eigenschaften von meso-arylsubstituiertem Decaphyrin oder Octaphyrin ändern sich gravierend, wenn eine 1,4-Phenylen-Brücke in die Makrocyclen eingefügt wird. In einem seiner beiden Oxidationszustände zeigt verbrücktes Decaphyrin einen starken diatropen Ringstrom. Röntg…
Einführen einer Ethylendithio-Einheit in einen amphiphilen Makrocyclus mit zwei anellierten Tetrathiafulvalen-Ringen führt zu Organogelen, die in Langmuir-Blodgett-Filmen Nanopunktanordnungen bilden (siehe Bild). Chemische Oxidation des schwefelhaltigen π-Elektronensystems liefert elektrisch leitende Nanopunktstruktur…