Materials Literature
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Osmoprotectants exogenously supplied to a hyperosmotic culture medium are efficiently imported and amassed by stressed cells of Escherichia coli. In addition to their evident role in the recovery and maintenance of osmotic balance, these solutes should play an important role on the behavior of cellular macromolecules,…
Current density and pH mapping techniques have been used to characterize the chemical and electrochemical phenomena which occur on the cut edge of galvanized steel. pH variations between 7 and 11 were observed, primarily due to the formation of hydroxyl ions by the cathodic reaction. Zinc‐based corrosion products prec…
Polyaniline (PANI) protonated with camphorsulfonic acid (CSA) is one of the most promising conductive polymers due to its relatively high crystallinity, high electrical conductivity, and the metallic characteristics at high temperatures, i.e., a positive temperature coefficient of resistivity. The crystalline structur…
Photochromic molecules are of great potential importance for optoelectronic devices. This communication presents the preparation of two new spiropyrans that display the first reported crystalline-state photochromism. UV irradiation of the pale yellow form produces the highly colored red form, both in the solid state a…
Alkenes and allylic alcohols have been epoxidized in an ambient-temperature ionic liquid for the first time using methyltrioxorhenium (MTO) and urea hydrogen peroxide; excellent conversions and selectivities for the epoxides of a wide number of substrates were observed.
A detailed analysis of the supramolecular architecture of the nanoporous surfactant-encapsulated cluster (SEC) with the empirical formula (DODA)40(NH4)2[(H2O)n ⊂ Mo132O372(CH3CO2)30(H2O)72] 1 (n ≈ 50) is presented. The open framework architecture of the Keplerate cluster is investigated by means of small angle neutron…
Aragonite thin films of calcium carbonate have been deposited on chitosan matrices by cooperation of chitosan, poly(aspartate) and MgCl2 in CaCO3 solution, and their double layered composite structures are obtained by the alternate operations of chitosan coating and thin-film crystallization.
(CGO) and (LSM) possess similar thermal expansion coefficients and were thus combined in dual‐phase membranes for oxygen separation. Studies of oxygen permeation through CGO‐LSM composite ceramics, containing similar volume fractions of the phases, showed that the oxygen transfer is limited by the bulk ionic conductiv…
This work deals in the first part, with the fire retardancy of polypropylene (PP)/thermoplastic polyurethane (TPU)/ammonium polyphosphate (APP) intumescent blends, using TPU with different chemical compositions. The influence of the chemical nature of the polyol used in the synthesis of the TPU on the fire resistance…
A palladium porphyrin has been covalently linked to a chiral lanthanide complex and effectively sensitises near-IR emission from Nd and Yb; sensitisation is enhanced in the absence of oxygen and in the presence of a nucleic acid.
To clarify the inconsistencies in existing elastic constant data of ${\mathrm{SrTiO}}_{3}$ in the vicinity of the 105 K phase transition we have studied the temperature dependence of the Young's modulus of ${\mathrm{SrTiO}}_{3}$ crystals. Dynamic mechanical analysis at 10--140 K and 10--45 Hz has been used for the exp…
Four polyols were prepared by a ring opening of epoxidized soybean oil with HCl, HBr, methanol, and by hydrogenation. Two series of polyurethanes were prepared by reacting the polyols with two commercial isocyanates: PAPI and Isonate 2143L. Generally, the properties of the two series were similar. The crosslinking den…
The elastic, piezoelectric, and dielectric properties of a 0.955Pb(Zn(1/3)Nb(2/3))O(3)-0.045PbTiO(3 ) (PZN-4.5%PT) multi-domain single crystal, poled along [001] of the original cubic direction, have been determined experimentally using combined resonance and ultrasonic methods. At room temperature, the PZN-4.5%PT sin…
A few examples of molecules containing a redox active core surrounded by an organic sheath have been synthesized recently. The redox nucleus may be attached covalently to the structure’s core or held there by noncovalent forces. This review article surveys the electrochemical behavior of such redox centers, emphasizin…
Thin films of symmetric diblock copolymers confined between two hard, flat and homogeneous surfaces have been investigated by means of Monte Carlo simulations on a simple cubic lattice. For such simulations, the match between bulk lamellar period L0 and the simulation box size is crucial to obtain meaningful results.…
Ordered macroporous zeolite fibres are prepared from the infiltration of swollen bacterial supercellular threads with as-synthesized silicalite nanoparticles.
In addition to the well-known α and β modifications, nickel hydroxide is shown to exist in a number of poorly crystalline forms—clearly distinguishable by their signature X-ray powder diffraction patterns. DIFFaX simulations combined with compositional analysis and IR spectral data indicate that these are interstratif…
The effect of the chemical substitution of Ti, Zr, and Gd cations on the structure and properties of bismuth‐based pyrochlores was investigated for (Bi 1.5 Zn 1.0 Nb 1.5 )O 7 and Bi 2 (Zn 2/3 Nb 4/3 )O 7 . Broad ranges of solid solutions based on cubic (Bi 1.5 Zn 1.0 Nb 1.5 )O 7 were observed for Ti and Zr cations: (B…
The crystallochemical structure of reduced Garfield nontronite was studied by X-ray absorption pre-edge and infrared (IR) spectroscopy, powder X-ray diffraction, polarized extended X-ray absorption fine structure (P-EXAFS) spectroscopy, and texture goniometry. Untreated and highly reduced (>99% of total Fe as Fe 2+…
The deposition of thin films of inorganic nanoclusters as a route to one-step lithography has been achieved using block copolymers with inherent inorganic (Fe and Si) components. Nanodomains of the organometallic part are resistant to removal during the subsequent O2 etch, which results in well-ordered and separate do…