Materials Literature
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Functional organic materials have been developed over the last twenty‐five years which compete for applications in optical, electrical and magnetic technologies with the more traditional inorganic network solids. In the first article of a regular series Joel Miller of DuPont describes some applications of these molecu…
A number of commercially available SiC and Si 3 N 4 materials were exposed to 1000°C for 40 h in a high‐velocity, pressurized burner rig as a simulation of an aircraft turbine environment. Na impurities (2 ppm) added to the burner flame resulted in molten Na 2 SO 4 deposition, attack of the SiC and Si 3 N 4 , and form…
Collagen intended for use as a dermal implant may be crosslinked to increase its strength and persistence in vivo. Sheets of rat fibrous dermal collagen were crosslinked with either glutaraldehyde or dimethylsuberimidate and the cytotoxicity to human dermal fibroblasts resulting from these treatments was measured by f…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn NMR study of plasticization and antiplasticization of a polymeric glassY. Liu, A. K. Roy, A. A. Jones, P. T. Inglefield, and P. OgdenCite this: Macromolecules 1990, 23, 4, 968–977Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Publis…
Abstract A series of semi‐interpenetrating polymer networks (semi‐IPNs) based on polyurethane and polydimethylsiloxane were prepared. They are formed by crosslinking the polydimethylsiloxane prepolymer with 3‐aminopropyltriethoxysilane in the presence of linear polyurethane. Investigations were carried out by swelling…
The relaxation of electric birefringence in dilute solutions of a polyelectrolyte is shown to be consistent with a stretched-exponential form, exp[-(t/\ensuremath{\tau}${)}^{\ensuremath{\alpha}}$]. The exponent \ensuremath{\alpha} depends on polymer length L and solvent ionic strength only through the ratio x==L/${L}_…
Lactate dehydrogenase was isolated from the extreme thermophilic eubacterium Thermotoga maritima. The enzyme is stereospecific for L(+)-lactate. It represents a homotetramer of 144 kDa molecular mass, with a sedimentation coefficient of s20,w approximately 7 S. Under physiological temperature conditions, the enzyme sh…
We present experimental results on bistable elements with liquid crystals as nonlinear elements showing that, under cw illumination, sequences of spatial structures occur. Index fluctuations, as a particular characteristic of this class of material, seem to play a central role in this effect. We describe the system an…
The passivity and corrosion behavior of several supersaturated aluminum alloys formed by cosputter deposition have been investigated. Several of these alloys exhibit superior resistance to localized attack in electrochemical polarization measurements and salt fog tests. X‐ray photoelectron spectroscopy was used to exa…
Treatment of racemic 2,3-epoxy aldehydes and ethyl nitroacetate with alumina affords title compounds through a nitroaldol reaction—cyclization process. While in the case of 3-trans-monosubstituted substrates, C4,C5-trans and cis isomers (dr = 1.5) with C5,C6-anti configuration are obtained, 3-cis-monosubstituted 2,3-e…
The characterization of the physicochemical nature of interfaces is a key problem in the field of advanced fibrous composites. The macroscopic regime contact angle, which reflects the energetics of wetting at the solid-liquid interface, is difficult to measure by usual methods in the case of very thin cylindrical fibe…
A new process is developed to form a ceramic containing a three‐dimensional network of metal reinforcement. The process involves four steps: (1) forming a powder compact containing a continuous network of either organic or carbon material by pressure filtration, (2) pyrolyzing the network to form channels within the p…
Potentiodynamically grown thin oxide films of zirconium were investigated as a function of the electrode potential ( 0 V ≤ V ≤ 9 V ) , the potential sweep rate ( 0.05 Vs − 1 ≤ v ≤ 4.00 Vs − 1 ) and the p H ( 1 ≤ p H ≤ 14 ) in phosphate electrolytes. The oxides were characterized by coulometric and impedance measuremen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPillaring of magadiite with silicate speciesRenato Sprung, Mark E. Davis, Jon S. Kauffman, and Cecil DybowskiCite this: Ind. Eng. Chem. Res. 1990, 29, 2, 213–220Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 Februar…
Abstract The miscibility of poly(viny1 alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) blends is investigated by differential scanning calorimetry (DSC) and wide‐angle x‐ray diffraction (WAXD). The molecular orientation induced by uniaxial stretching of the blends is also examined by WAXD and birefringence measurements. It…
Polycrystalline specimens of Al 68 Ru 15 Cu 17 icosahedral quasicrystals are brittle below 1000 K but plastically deformable above 1000 K with the flow stress sensitively depending on the strain-rate. The activation analyses show that the activation volume is less than 1 nm 3 at high stress and 10 nm 3 at low stress.…
A quenched equilibrium state of a $^{65}31$.1 at. % Zn single crystal was investigated by elastic diffuse neutron scattering. The short-range order intensity showed maxima that could be related to the flat portions of the Fermi surface perpendicular to the 〈110〉 directions. Effective pair potentials ${V}_{\mathrm{lmn}…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMorphology of molybdena supported on various oxides and its activity for methanol oxidationYoshihito. Matsuoka, Miki. Niwa, and Yuichi. MurakamiCite this: J. Phys. Chem. 1990, 94, 4, 1477–1482Publication Date (Print):February 1, 1990Publication History Published online1 May…
The chemistry and physics pertinent to the various steps of MOD processing are discussed, and areas where more basic research is needed are pointed out. The preparation and properties of MOD films of PbTiO3, BaTiO3, Pb(Zr,Ti)O3, (Pb,Sr)TiO3 and (Pb,La)(Zr,Ti)O3 are discussed.
Magnetization curves have been measured in the temperature range from 4.2 to 300 K along the [100], [110], and [001] directions of a Dy(${\mathrm{Fe}}_{11}$Ti) single crystal in fields up to 7 T. The magnetic moment is along [100] below 58 K and parallel to the c axis above 200 K. Between the two spin-reorientation tr…