Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLarge metal ion-centered template reactions. Chemical and spectral studies of the "superphthalocyanine" dioxocyclopentakis(1-iminoisoindolinato)uranium(VI) and its derivativesTobin J. Marks and Djordje R. StojakovicCite this: J. Am. Chem. Soc. 1978, 100, 6, 1695–1705Publicat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExpansion of molecular orbital wave functions into valence bond wave functions. A simplified procedureP. C. Hiberty and C. LeforestierCite this: J. Am. Chem. Soc. 1978, 100, 7, 2012–2017Publication Date (Print):March 1, 1978Publication History Published online1 May 2002Publi…
Electron spectroscopy for chemical analysis (ESCA) was used to study the surface composition of several radiation-grafted polymers in both the dry and hydrated (frozen at 160°K) states. Poly(2-hydroxyethyl methacrylate) (HEMA) and polyacrylamide, both hydrophilic polymers, were readily detected in the hydrated or dehy…
Abstract Highly stretched rubber sheets can be split apart quite easily, indicating that the originally isotropic material becomes “fibrous” in character— i.e. , much weaker for a tear running in the direction of extension than for one running at right angles to it. This anisotropy of strength is shown most clearly by…
A variable surface acoustic wave (SAW) delay line was fabricated using a thin (<1 μm) magnetostrictive film, metallic-glass overlay. It is well known that metallic-glasses can be prepared in ribbon form by rapid quenching from the melt. However, it is difficult to prepare thin film overlays of these materials f…
Materials prepared by modifying sulfur with dicyclopentadiene or styrene consist of unreacted sulfur and polysulfides. Dicyclopentadiene reacts with sulfur to give, initially, low-molecular-weight polysulfides (e.g., a pentasulfide) which convert to high-molecular-weight polymers at 140°C. Styrene initially gives high…
Bacillus subtilis grown at temperatures below 37 degrees contains two thymidylate synthetases, TSaseA and TSaseB. Their presence is dependent on functional thyA and thyB genes, respectively. When cells are grown at 46 degrees they only contain TSaseA activity. This allous an easy positive selection for thyA and thyA,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTime Resolved Fluorescence Studies of Poly(N-vinylcarbazole), Poly(1-vinylnaphthalene), and 1,3-Bis(N-carbazolyl)propaneC. E. Hoyle, T. L. Nemzek, A. Mar, and J. E. GuilletCite this: Macromolecules 1978, 11, 2, 429–431Publication Date (Print):March 1, 1978Publication History…
To determine if MgO added within the solubility limit in Al 2 O 3 is sufficient to suppress discontinuous grain growth, an undoped alumina pellet was sintered next to a preequilibrated, two‐phase mixture of spinel (MgAl 2 O 1 ) and alumina. The MgO‐doped outer surface of the undoped pellet did sinter to full density;…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of the toluene solvate of .alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatozinc(II)W. Robert Scheidt, M. E. Kastner, and K. HatanoCite this: Inorg. Chem. 1978, 17, 3, 706–710Publication Date (Print):March 1, 1978Publication History Published online1 May 20…
The structures of (Na,K)NbO3 solid solutions have been determined by using the neutron powder-profile refinement technique: phases K and L at room temperature, and G and F at higher temperatures. In each case approximate values have been found for position parameters and temperature factors. The structural models prop…
There have been few studies using ionizing photons higher in energy than Al Kα (1487 eV). However, characteristic x rays such as Au Mα (2123 eV) and Ag Lα (2984 eV) are nearly as narrow in energy, and can provide deeper core photoelectron lines and their companion core-type Auger lines in the spectra of 26 elements th…
The many types of chemical-bonding arrangements which can characterize primarily covalent amorphous semiconductors are enumerated and discussed. Emphasis is given to local structures which are difficult to achieve in significant concentrations in crystalline solids but are readily attainable in amorphous materials via…
Changes induced in the orientation of the axes of crystallites in thin films of polyvinylidene fluoride by the application of 6×107 V/m at 100 °C for 1/2 h have been observed. The changes were observed by measuring the intensity of x rays diffracted from the film as a function of the orientation of the film relative t…
Se trata de exponer, actualizada a la fecha presente, la creciente actividad científico-técnica (así como los resultados de la misma) en el campo de la fisicoquímica y de la tecnología del CEMENTO, llevada a cabo en Iberoamérica desde 1969 por el Departamento de Química y en parte por el de Materiales, y más recientem…
El estudio del efecto de un determinado aditivo sobre la corrosión de las armaduras, o el de un hormigón con fisuras, o sometido a ambientes marinos o, en fin, de cualquier factor o circunstancia calificada como agresiva, suele exigir un laborioso y extenso programa de trabajo que contemple todas las posibilidades por…
En una publicación anterior (1) se estudió el comportamiento de los morteros correspondientes a dos cementos portland, sometidos a la acción del agua de mar, determinando la evolución de las resistencias mecánicas a flexión; la variación de los coeficientes de corrosión (Koch-Steinegger) a 7, 28 y 56 días; la modifica…
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