Materials Literature
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Multistep template synthesis offers an easy and general route to complicated nanostructures. A two‐step replication procedure is described that can be used to prepare nanotubes of titanium dioxide (see Figure) or other semiconducting materials. The requirements placed on the starting material, the synthesis route, and…
New electrochromic materials (ECMs) must exhibit rapid response times, long‐term stability, and a large difference in percentage transmittance between the bleached and colored states. The design, fabrication, and characterization of fast, solid‐state, dual conducting polymer EC devices that utilize PEDOT (see Figure)…
Unsymmetrical zinc(II) complexes of benzonaphthoporphyrazines 5a-12a bearing between one and eight pyridyloxy substituents are synthesized by statistical tetramerization of 6-(1,1-dimethylethyl)-2,3-naphthalenedicarbonitrile (1) with 4-(3-pyridyloxy)- or 4,5-bis-(3-pyridyloxy)-1,2-benzenedicarbonitrile (2, 3). Methyla…
The viscosity T/of dry and hydrous haplogranitic melts (anhydrous normative composition: QZ28Ab340r38)has been determined between 3 and 10 kbar and 800 and 1400 DC using the falling-sphere method. The H20 content of the melt ranged from 0.03 to 8.21 wt%. Experiments were performed in internally heated pressure vessels…
An ab initio theoretical study of the optical absorption spectrum of Ni2+-doped MgO has been conducted by means of calculations in a MgO-embedded (NiO6)10−cluster. The calculations include long- and short-range embedding effects of electrostatic and quantum nature brought about by the MgO crystalline lattice, as well…
Abstract Acid‐catalyzed condensation of tripyrranes with pyrrole‐2,5‐dicarboxaldehydes, followed by oxidation with an electron‐deficient quinone, affords porphyrin products in excellent yields. This previously little used methodology has now been exploited in the synthesis of novel porphyrin structures, including tetr…
DegP and DegQ are homologous endoproteases found in the periplasmic compartment of Escherichia coli. The studies presented here suggest that DegP and DegQ have very similar substrate specificities and cleave substrates which are transiently or globally denatured. Model substrates were cleaved at discrete Val/Xaa or Il…
This paper gives a general overview of several approaches we have investigated for designing new PLA-based polymers with a broad range of properties and improved processability. These approaches include: copolymerization (block and stereoblock copolymers), microstructure and architecture control, and stereocomplexatio…
Although synthetic materials are now widely used in implanted medical devices, they are not engineered for recognition and specificity. This article considers the design of polymer surfaces that might be specifically recognized and trigger normal healing pathways. The technological advances that will contribute to bio…
The properties and origins of the red, blue and infrared photoluminescence bands of porous silicon are reviewed and discussed in the light of the models that have been proposed to explain the experimental and theoretical results. The red band is due to quantum confinement possibly supplemented by surface states; the b…
Abstract The vinylic polymerization of norbornenes upon catalysis with Pd 2+ complexes with norbornylnitrile as ligands is reported. The polynorbornenes ( M̄ w = 10 6 ) display a set of unique properties including a dense packing in the amorphous state, high glass transition temperatures, large refractive index, low b…
Peripherally alkyl‐substituted aromatic molecules are of interest because they are predicted to promote the rapid vectorial conduction of electronic charge. It is shown—using the example of HHTT, see Figure—that the results obtained by flash‐photolysis time‐of‐flight conductivity and pulse‐radiolysis time‐resolved mic…
To increase the reliability of multilayer actuators, calculation of the mechanical stress inside the device during operation is important. This paper shows that the small‐signal value of the elastic constant s is not sufficient to describe the complicated behavior of lead zirconate titanate (PZT) ceramics. Therefore,…
GTP binding proteins (G-proteins) have wide-ranging functions in biology, being involved in cell proliferation, signal transduction, protein synthesis, and protein targeting. Common to their functioning is that they are active in the GTP-bound form and inactive in the GDP-bound form. The protein synthesis elongation f…
The local dynamics of 1,4 polybutadiene below and above the merging of the \ensuremath{\alpha} and \ensuremath{\beta} relaxations have been investigated by combining neutron spin echo (NSE) and dielectric spectroscopy. The study of the dynamic structure factor measured by NSE over a wide momentum transfer range allows…