Materials Literature
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A drop-tube-processed Al-3.6wt.%Fe representative droplet of about 500 μm diameter shows the two-zone fine cellular-coarse cellular α-Al structure, hitherto reported only in as-atomized hypereutectic AlFe powder particles of less than 50 μm diameter. The origin of the transitional microstructure is analysed in terms…
Five selected S-alkylisothisothiouronium iodides have been studied as acid corrosion inhibitors at 30°C for steel in 0.5 M H2SO4 using gasometry, mass loss, and direct current (DC) polarization techniques. All of the data reveal that the compounds act as inhibitors in the acid environments; furthermore, polarization c…
Theoretical calculation shows that suitable approximations of the line-shape asymmetry in powder diffraction profiles should be represented by functions having limited codomains.
Abstract Triblock copolymers were prepared from L‐lactide and a poly(ethylene glycol) of M̄ n = 1020. With GeO 2 and SnO 2 only low conversions were obtained, regardless of the reaction temperature. Sb 2 O 3 caused partial racemization, and only SnO gave satisfactory results. When other samples of poly(ethylene glycol…
Macromolecular structure determination by X-ray crystallography and solution NMR spectroscopy has experienced unprecedented growth during the past decade.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRigid bowlic liquid crystals based on tungsten-oxo calix[4]arenes: host-guest effects and head-to-tail organizationBing Xu and Timothy M. SwagerCite this: J. Am. Chem. Soc. 1993, 115, 3, 1159–1160Publication Date (Print):February 1, 1993Publication History Published online1…
In the strong versus fragile classification of simple liquids near their glass transition, a simple model is used to quantify this distinction, which sheds light on mechanisms in glass-forming liquids near freezing. From this model it is shown that the fragility parameter, one of the most important material constants,…
Arc discharging carbon rods containing 8.8 wt% La 2 O 3 produces a carbonaceous deposit containing nano-particles (nm-size particles) consisting of graphite shells around core nano-crystals averaging 10-30 nm in diameter but sometimes 3-4 nm. Transmission electron microscopy, nm-size electron diffraction and electron…
The structure of n-fold rings in vitreous ${\mathrm{SiO}}_{2}$ is investigated using molecular-dynamics configurations. A recently developed interaction potential for ${\mathrm{SiO}}_{2}$ consisting of long-range Coulomb interactions, the effect of electronic polarizability, and three-body covalent forces is used in t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron correlation effects in hyperpolarizabilities of p-nitroanilineFiona Sim, Steven Chin, Michel Dupuis, and Julia E. RiceCite this: J. Phys. Chem. 1993, 97, 6, 1158–1163Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published ini…
Branden & Jones state, in Nature: `Protein crystallography is an exacting trade, and the results may contain errors that are difficult to identify. It is the crystallographer's responsibility to make sure that incorrect protein structures do not reach the literature.' [Branden & Jones. (1990). Nature (London), 343, 68…
The fracture behavior of Al 2 O 3 containing 5 vol% 0.15μm SiC particles was investigated using indentation techniques. A significant increase in strength was achieved by the addition of SiC particles to the base Al 2 O 3 . Specifically, the strength increased from 560 MPa for Al 2 O 3 to 760 MPa for the composite sam…
Preparation of high quality conducting poly( trans ‐TTTE) and poly( trans ‐BTTTE) by the electrochemical polymerization of oligothiophene derivatives such as trans ‐(thiophene‐2‐yl)‐2,2':5'2''‐terthiophene‐5‐yl)ethylene, trans ‐TTTE, and trans ‐(2,2'‐bithiophene‐5‐yl)‐2,2':5'2''‐terthiophene‐5‐yl)ethylene, trans ‐BTTT…
Abstract The doubly differential cross-section for weak inelastic scattering of waves or particles by manybody systems is derived in Born approximation and expressed in terms of the dynamic structure factor according to van Hove. The application of this very general scheme to scattering of neutrons, x-rays and high-en…
Abstract Single-crystal structure determinations of wolframite-type structures were performed using a diamond anvil cell with beryllium gaskets. Unit cell parameters of MgWO 4 , MnWO 4 and CdWO 4 were determined at several pressures up to 8.0 GPa and structure refinements were performed up to 6.0 GPa. The high pressur…
Employing photoluminescence (PL) spectroscopy, we have carried out a detailed study of the characteristics and origin of the 1.681 eV luminescence center in chemical-vapor-deposited (CVD) diamond films. In addition to the zero-phonon line (ZPL), the fine structure of the PL emission spectrum revealed vibronics corresp…
Abstract Na9[EuW10O36]·32H2O, obtained from aqueous solutions, crystallizes in space group Cc with a = 11.484(5), b = 23.020(7), c = 23.581(6) Å, β = 91.71(3)°, V = 6231(3) Å3, Mr = 3349.4, Dx = 3.57 Mg m−3, and Z = 4. A full-matrix least-squares refinement finally yields R = 0.070 and Rw = 0.086 for 6473 independent…
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…