Materials Literature
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delta-Aminolevulinate in plants, algae, cyanobacteria, and several other bacteria such as Escherichia coli and Bacillus subtilis is synthesized from glutamate by means of a tRNA(Glu) mediated pathway. The enzyme glutamyl tRNA(Glu) reductase catalyzes the second step in this pathway, the reduction of tRNA bound glutama…
The stress-stress correlation function and the viscosity of a united-atom model of liquid decane are studied by equilibrium molecular dynamics simulation using two different formalisms for the stress tensor: the atomic and the molecular formalisms. The atomic and molecular correlation functions show dramatic differenc…
Eine Brücke zwischen Porphyrinen und Annulenen schlagen die Carbaporphyrine 1 (R = H und CH 3 ), in denen ein Stickstoffatom des Porphyrin‐Grundgerüsts durch Kohlenstoff ersetzt wurde. Diese neuartigen Verbindungen sind ebenfalls 18π‐Arene und haben ähnliche spektroskopische Eigenschaften wie die Porphyrine. magnified…
The shear viscosity of Bi - Ga melts in the entire concentration range was measured using an oscillating-cup viscometer. The viscosity data well above the temperature of phase separation can be represented by an empirical equation of the Arrhenius type. The activation energies of viscous flow are given. In the vicinit…
Zwei verzerrte, hexagonale Fe 6 O 6 ‐ Prismen , die über eine gemeinsame Vierecksfläche verknüpft sind, bilden das Zentralgerüst (Bild rechts) des zehnkernigen Eisenkomplexes 1 . Magnetischen Messungen zufolge hat die Käfigverbindung einen Highspin‐Grundzustand mit S = 11 oder 12. Hchp = 6‐Chlor‐2‐pyridon. [Fe 10 Na 2…
In this letter we report on the pulsed laser epitaxial deposition of thin films of Sr0.75Ba0.25Nb2O6 on MgO substrates with measured diagonal Pockel’s coefficient r33=844 pm/V in these films. This is the largest linear electro-optic coefficient reported to date in a thin film material. In order to measure this coeffic…
Subwavelength structured (SWS) surfaces etched directly into different substrates provide performance equivalent to an ideal anti-reflection thin film. We report on SWS surfaces etched into silicon which present anti-reflection properties for visible light. The fabrication of the SWS component is based on a double hol…
To explore the origin of the recently discovered non-Arrhenius behavior of the dc conductivity in glassy fast ionic conductors at high temperatures, we investigate by Monte Carlo simulations the transport of charged particles in an energetically disordered structure. We show that the combined effect of Coulomb interac…
Epitaxial hcp and bcc Cu and Pd films were grown on W(100). The epitaxial relation of the hcp films is determined by reflection high energy electron diffraction (RHEED) as $(11\overline{2}0)\ensuremath{\parallel}(100)$ and $[0001]\ensuremath{\parallel}[011]$. The growth of hcp Cu and Pd is attributed to the much small…
By electrolysis of the methanol solution, an attempt was made to deposit diamondlike carbon (DLC) films on silicon substrate at temperature of less than 60 °C. Substrates were negatively biased with a dc potential of 0 to −3000 V. IR spectra showed that the O–H, C–H, and C–O vibration bands of electrolyte decreased re…
A giant permittivity associated with the motion of domain walls is reported in epitaxial hetero- structures having alternating layers of ferroelectric and nonferroelectric oxides. At low frequencies, permittivities as high as 420 000 are found. Real and imaginary parts of the dielectric constant show large dispersion…
Kink defects in the 90\ifmmode^\circ\else\textdegree\fi{} partial dislocation in silicon are studied using a linear-scaling density-matrix technique. The asymmetric core reconstruction plays a crucial role, generating at least four distinct kink species as well as soliton defects. The energies and migration barriers o…
Five structural phase transitions have been observed in the perovskite-type layer compound (C6H13NH3)2PbCL4 using differential scanning calorimetry, X-ray diffraction, and vibrational analysis. Phase IV, stable at low temperature, has an ordered structure. The phase transition IV → III', which is of first-order type,…
Side-chain ferroelectric liquid crystalline polymers are currently used in a number of applications, including displays and electrical sensors. Comparisons with existing technologies and materials indicate that relative to ceramics, such polymers have lower figures of merit but offer greater durability in sensor appli…
Measurements of low levels of strain birefringence in fused silica glass have been made using a system based on a photoelastic modulator. Measurements of sample net retardation have been made with a resolution of 0.1 nanometers. Measured values of a strain birefringence constant for fused silica are in good agreement…
A conceptual foundation for the study of local non-equilibrium solute diffusion under rapid solidification conditions is proposed. The model takes into account the relaxation to local equilibrium of the solute flux and incorporates two diffusion speeds, VDb, the bulk liquid diffusion speed, and VDi, the interface diff…
Long nanotubes of fluid-lipid bilayers can be used to create templates for photochemical polymerization into solid-phase conduits and networks. Each nanotube is pulled from a micropipette-held feeder vesicle by mechanical retraction of the vesicle after molecular bonding to a rigid substrate. The caliber of the tube i…
The molecular organization in ultrathin polymer films (thicknesses less than 1000 angstroms) and thin polymer films (thicknesses between 1000 and 10,000 angstroms) may differ substantially from that of bulk polymers, which can lead to important differences in resulting thermophysical properties. Such constrained geome…
Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inheren…
Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films…