Materials Literature
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The characterization of nanometer-scale phase separation in sputtered, amorphous, metal-Ge and Fe-Si films has led to the observation of a new microstructure that extends through the metal-insulator transition. The phase separated regions, which are dependent on deposition conditions, are well correlated and of the or…
Abstract In this article, the graft copolymerization of methy methacrylate with canna‐starch under the initiating of manganic pyrophosphate was investigated systemly. It was found that the percentage of grafting, grafting efficiency, and rate of grafting were all dependent, to some extent, on the concentration of the…
OBJECTIVE: The purpose of this study was to demonstrate that gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) could be used as a contrast medium in CT as an alternative to iodine-based compounds. MATERIALS AND METHODS: Solutions of different concentrations of Gd-DTPA and iopromide were scanned in a tissue equi…
We present a new electro-chemical method for incorporating high concentration Er ions deep into porous silicon layers and its intense photoluminescence at ∼1.54 μm at room temperature. Porous silicon layers prepared by anodic etching of p-type silicon substrates in HF/H2O are immersed in ErCl3/ethanol solution. Then t…
Abstract Binary blend films from lactide‐rich poly( D ‐lactide‐co‐glycolide) (PDLG) and poly( L ‐lactide‐co‐glycolide) (PLLG) were obtained by casting methylene chloride solutions of the two mixed copolymers with different D‐ and L‐lactide contents ( X DI and X LI ), and their crystallization was studied by differenti…
The response of a soft-phonon ferroelectric material subjected to a high-intensity optical pulse of duration much shorter than the period of the phonon is modeled using a classical, finite-temperature simulation. It is found that complete, permanent reversal of the orientation of the ferroelectric domains may occur ev…
Abstract Stress relaxation behavior of chemically treated short sisal fiber‐reinforced natural rubber composite was studied. The effect of bonding agent, strain level, fiber loading, fiber orientation, and temperature has been studied in detail. The existence of a single relaxation pattern in the unfilled stock and a…
Abstract This article examines the blood compatibility of chitosan grafted with 2‐hydroxyethyl‐methacrylate (HEMA) using 60 Co gamma radiation. The effect of various syntheses conditions on the grafting was determined. The solvent composition has a marked effect on the degree of grafting. Maximum yield was obtained in…
Switchable polarization can be significantly suppressed in Pb(Zr,Ti)O3 thin films by optical, thermal, and electrical processes. The optical (thermal) suppression effects occur by biasing the ferroelectric near the switching threshold and illuminating the material with band-gap light (heating the material to ≊100 °C).…
Abstract The effect of zinc catalysts on the hydrolytic depolymerization of polyethylene terephthalate (PET) melts in excess water was studied using a 2‐L stirred pressure reactor at temperatures of 250, 265, and 280°C. The main products of the reaction were found to be terephthalic acid, ethylene glycol, and diethyle…
Computer simulations and experimental studies were combined to design copolymers that enhance the strength of polymer composites. These copolymers contain side chains that associate across the boundary between phase-separated regions to form a "molecular velcro" that effectively binds the regions together. This behavi…
The scaling of the cubic nonlinearity gamma with chain length in polyenic molecules has received considerable theoretical attention. Earlier experimental investigations have been restricted to oligomers with fewer than 20 double bonds because of problems associated with the synthesis and solubility of conjugated molec…
Clusters of metal ions are a class of compounds actively investigated for their magnetic properties, which should gradually change from those of simple paramagnets to those of bulk magnets. However, their interest lies in a number of different disciplines: chemistry, which seeks new synthetic strategies to make larger…
Bis zur vierten Generation sind neutrale, phosphorhaltige Dendrimere auf dem hier beschriebenen Weg in guten Ausbeuten zugänglich. Als einzige Nebenprodukte entstehen NaCl und H 2 O, und die Produkte enthalten hochreaktive Funktionalitäten an der Peripherie. Rechts ist das Dendrimer der ersten Generation gezeigt. magn…
In einer simplen Eintopfreaktion sind die Wirt‐Gast‐Verbindungen 1 (weiße Kugeln=Fe III , schwarze = Fe II , graue = NH , abgewinkelte Stäbe= 2 ) in Gramm‐Mengen durch Selbstorganisation zugänglich. Sie sind die einzigen vollständig charakterisierten Redoxisomere, deren Cyclovoltammogramme vier quasireversible Wellen…
Flüssigkristallines Verhalten über einen weiten Temperaturbereich und reversible Phasenübergänge zeigt das Polymernetzwerk 1 , das durch Wasserstoffbrückenbindungen zwischen den Benzoesäure‐ und den Bipyridyleinheiten zusammengehalten wird. magnified image
Abstract Die Rolle von Metalloenzymen in wichtigen biologischen Prozessen hat in den letzten Jahrzehnten zunehmend Beachtung gefunden. Von den vielen chemischen Reaktionen, die durch Enzyme gesteuert werden, sind nur wenige eine so große Herausforderung wie die Mehrelektronen‐Redoxreaktionen. In neueren Untersuchungen…
Investigations of the infrared and polarized Raman spectra of Cd(HCOO)2 · 2 H2O reveal the presence of two crystallographically nonequivalent formate ions as separate frequencies are observed for each internal mode. The symmetric CO2 stretching mode is observed in between the two components of the in-plane OCH bending…
Les propriétés optiques d'une série d'oxydes mixtes du systeme BaO-RE2O3 (RE = Gd, Y), de formule générate BaRE2O4 sont analysées. L'europium trivalent est utilisé comme dopant actif, remplaçant en partie l'élément de terre rare de la matrice. La quantité du dopant est faibic (2%) et n'altßre pas la structure. D'après…
The Raman spectra of Bi2Ti4O11 at hydrostatic pressure or high temperature show that the frequency of the soft mode has a non-zero value at the phase transition point. The Raman spectra of Bi1.8La0.2Ti4O11 and Bi1.8Yb0.2Ti4O11 at high pressure reveal that there is an additional phonon mode in the low-frequency region.…