Materials Literature
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Abstract Functional aluminum alkoxides, such as Et 3– p Al(OCH 2 X) p , where p = 1,3 and X = a functional group, are very effective initiators for the (D, L)‐lactide polymerization in toluene at 70°C. The coordination‐insertion type of polymerization is living. Linear polyesters of a predictable molecular weight an…
Abstract β‐Chitin was isolated from squid pens, and the characteristic chemical and physical properties were elucidated in comparison with those of shrimp chitin, α‐chitin. Deacetylation behavior of the squid chitin was first studied to look into the reactivity of β‐chitin and also to establish an efficient procedure…
Abstract The mechanical behavior of glassy polymers is time and temperature dependent as evidenced by their viscoelastic and viscoplastic response to loading. The behavior is also known to depend strongly on the prior history of the material, changing with time and temperature without chemical intervention. In this in…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoisomerization and second harmonic generation in disperse red one-doped and -functionalized poly(methyl methacrylate) filmsR. Loucif-Saibi, K. Nakatani, J. A. Delaire, M. Dumont, and Z. SekkatCite this: Chem. Mater. 1993, 5, 2, 229–236Publication Date (Print):February 1,…
We have applied unique types of carbon foams developed at Lawrence Livermore National Laboratory to make an "Aerocapacitor." The aerocapacitor is a high power‐density, high energy‐density, electrochemical double‐layer capacitor which uses carbon aerogels as electrodes. These electrodes possess very high surface area p…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA luminescent silicon nanocrystal colloid via a high-temperature aerosol reactionK. A. Littau, P. J. Szajowski, A. J. Muller, A. R. Kortan, and L. E. BrusCite this: J. Phys. Chem. 1993, 97, 6, 1224–1230Publication Date (Print):February 1, 1993Publication History Published on…
I have carried out numerical first-principles calculations of the pressure dependence of the elastic moduli for several ordered structures in the aluminum-lithium system, specifically fcc Al, fcc and bcc Li, L${1}_{2}$${\mathrm{Al}}_{3}$Li, and an ordered fcc ${\mathrm{Al}}_{7}$Li supercell. The calculations were perf…
With the assumption that both size- and strain-broadened profiles of the pure-specimen function are described with a Voigt function, it is shown that the analysis of Fourier coefficients leads to the Warren–Averbach method of separation of size and strain contributions. The analysis of size coefficients shows that the…
A novel method was developed to prepare three-dimensional structures with desired shapes used as templates for cell transplantation. The produced biomaterials are highly porous with large surface/volume and provide the necessary space for attachment and proliferation of the transplanted cells. The processing technique…
The optical, electronic, and catalytic properties of semiconductor Q‐particles differ significantly from those of either the bulk materials or of the molecules, as the nanometer‐size particles exhibit effects due to quantum confinement. The methods of preparing these materials, their characterization, their properties…
Classical continuum models, i.e. continuum models that do not incorporate an internal length scale, suffer from excessive mesh dependence when strain‐softening models are used in numerical analyses and cannot reproduce the size effect commonly observed in quasi‐brittle failure. In this contribution three different app…
Heat conduction in dielectric thin films is a critical issue in the design of electronic devices and packages. Depending on the material properties, there exists a range of film thickness where the Fourier law, used for macroscale heat conduction, cannot be applied. This paper shows that in this microscale regime, hea…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAssembly, structural characterization, and thermal behavior of layer-by-layer deposited ultrathin films of poly(vinyl sulfate) and poly(allylamine)Yuri Lvov, Gero Decher, and Helmuth MoehwaldCite this: Langmuir 1993, 9, 2, 481–486Publication Date (Print):February 1, 1993Publ…
Simulated annealing is a probabilistic method proposed in Kirkpatrick, Gelett and Vecchi (1983) and Cerny (1985) for finding the global minimum of a cost function that may possess several local minima. It works by emulating the physical process whereby a solid is slowly cooled so that when eventually its structure is…
Crystals of bovine trypsin were acylated at the reactive residue, serine 195, to form the transiently stable p-guanidinobenzoate. Hydrolysis of this species was triggered in the crystals by a jump in pH. The hydrolysis was monitored by three-dimensional Laue crystallography, resulting in three x-ray diffraction struct…
Fumarase A, a product of the fumA gene of Escherichia coli, has been found to catalyze the isomerization of enol to keto oxalacetic acid (OAA) in addition to catalyzing the fumarase reaction. The kcat/Km for the isomerization is almost identical to that for the fumarase reaction. The isomerization reaction apparently…
We have examined the interaction of Citrobacter freundii tyrosine phenol-lyase with both L- and D-alanine. This enzyme catalyzes the racemization of alanine as a side reaction, in addition to the physiological beta-elimination of L-tyrosine to give phenol and ammonium pyruvate. The steady-state kinetic parameters for…
Glycine is found as every third residue along the entire length of triple helices in fibrillar collagens, but the triple-helix regions of nonfibrillar collagens and other proteins usually contain one or more interruptions in this repeating pattern. A set of four peptides was designed to model the effect of interruptio…
The technique of Raman scattering has been used to investigate the properties of ferroelectric PbTiO3 thin films grown on both single-crystal KTaO3 and fused quartz substrates by means of metalorganic chemical vapor deposition. The ‘‘difference Raman’’ technique was employed in which substrate contributions were subtr…
The atomic structure of the (310) twin in Nb was predicted using interatomic potentials derived from the embedded atom method (EAM), Finnis-Sinclair theory (FS), and the model generalized pseudopotential theory (MGPT). The EAM and FS predicted structures with crystal translations which break mirror symmetry. The MGPT…