Materials Literature
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The Azotobacter vinelandii nifE gene was isolated and its complete nucleotide sequence was determined. The amino acid sequences deduced from the A. vinelandii nifE and nifD gene sequences were compared and found to share striking primary sequence homology. This homology implies a functional and possibly an evolutionar…
Iron thin films with soft magnetic properties have been deposited by Dual Ion Beam Sputtering. And the dependence of their crystal structure and magnetic properties on preparation conditions, especially on ion bombardment onto film surface during deposition, has been investigated. All films are composed fine crystalli…
Boron carbide compacts sintered between 2220° and 2250° C showed abnormal grain growth that was associated with twinning and microcracking. The twin direction was 〈011〉. The microcracking was linked to thermal expansion anisotropy determined by high‐temperature lattice constant measurement.
The effect of additions of B, Al, and B + Al on the pressureless sintering of β‐Sic was examined. The influence of the sintering atmosphere and heating schedule on densification behavior, polytype transformation, and microstructure development was also studied. High densities were obtained at 1940°C by the simultaneou…
Extensive high-resolution heat-capacity measurements have been carried out near the smectic-A--hexatic-B transition of various compounds in the homologous series of n-alkyl-4'-n-alkoxybiphenyl-4-carboxylate. In contrast with the nematic--smectic-A and smectic-A--smectic-C (or chiral-smectic-C) transitions, the critica…
In a flux-grown SrTiO3 crystal, monodomain and polydomain regions have been observed below the transition temperature without applying external stress. For each region, measurements of the lattice constant as a function of temperature are made by means of high-angle double-crystal X-ray diffractometry (HADOX) with a p…
Since the Curie temperature (Tc) of R-Fe-B permanent magnets is lower than conventional 1/5 and 2/17 magnets, the irreversible loss due to the change of coercivity is critical when considering their application. The simple way to guarantee the thermal properties is to raise the coercivity at room temperature. The effe…
Thermal expansion was measured for skull‐melt‐grown undoped single‐crystal zirconia as well as for crystals containing 2.8 wt% MgO, 4 wt% CaO, and 3 to 20 wt% Y 2 O 3 . Samples were cycled in air from room temperature to 1500°C. The partially stabilized samples experienced a phase transformation which was strongly dep…
A technique is described to join Si 3 N 4 ceramics using oxide glasses. The technique involves a glazing step, followed by a pressureless reaction treatment of 30 to 60 min at 1575° to 1650°C. Reactions between the glasses and Si3N4 are reported. Important events are dissolution of Si 3 N 4 and the growth of Si 2 N 2…
A method for measuring assimilation efficiencies based on the change in the Si : 14 C ratio in food and feces is proposed. Since this indicator method uses biogenic silica as the inert substance, the method is restricted to aquatic herbivores that consume food containing it. The method has been demonstrated on adult f…
The development of amorphous TbFeCo alloy films is summarized and from the dynamic read/write characteristics, TbFeCo films are confirmed to be very useful for digital memory applications. That is, the value of C/N is more than 50 dB and life times of more than 5 years were obtained even in the case of a PMMA substrat…
The decomposition of trimethylaluminum (TMA) on copper, aluminum, quartz, and gallium arsenide substrates has been studied as a function of substrate temperature from 550–900 K under low pressure conditions. Detection of gaseous products was carried out by laser multiphoton ionization mass spectrometry (MPI/MS) for me…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformation, bonding, and flexibility in short-chain linear phosphazenesHarry R. Allcock, Norris M. Tollefson, Robert A. Arcus, and Robert R. WhittleCite this: J. Am. Chem. Soc. 1985, 107, 18, 5166–5177Publication Date (Print):September 1, 1985Publication History Published…
Abstract The diffusion of organic solvents in concentrated polymer solutions often deviates from the predictions of Fick's second law, especially when the solution is in the glassy state; such behavior is called anomalous or non‐Fickian. This paper analyzes the one‐dimensional sorption of a solvent into a concentrated…
The molybdenum bronzes A0·30MoO3, A0·9Mo6O17 and Mo4O11 oxides all show low-dimensional electronic properties, due to anisotropic crystal structures, which lead to charge-density-wave (CDW) instabilities. In the CDW states of the quasi-one-dimensional blue bronzes, non-linear transport properties are attributed to the…
The response of a material under uniaxial compression depends both on the bulk material properties and on the frictional effects at the sample‐platen interface. Three commercial cheeses (cheddar, mozzarella and processed cheese spread) were studied in uniaxial compression. Frictional effects at the sample surface were…
The enhancement of electromagnetic processes on metallic surfaces is discussed in view of applications in surface photochemistry and surface analytics. The strongest enhancements are found on substrates that consist of discrete metal particles. A theoretical description for plasmon resonances of such particles is deve…
The compositions of air-formed passive films on ferritic stainless steel (SS) were modified by exposure in solutions containing CrO-2, MoO4-2, and WO4-2 ions. The steel samples prepared in this manner were investigated for their pitting resistance in 3% NaCl by measuring the pitting nucleation potential. Auger electro…
Abstract Chemical analyses for ganomalite from Franklin, New Jersey, and Jakobsberg, Nordmark, Sweden, imply that Mn is an essential element and that the formula is Pb 9 Ca 5 MnSi 9 O 33 , with Z = 1 for the hexagonal unit cell. Preliminary crystal structure data confirm that Mn and Ca are ordered, as implied by the c…
Germanium and phosphorus diffusion were studied in binary GeO 2 ‐SiO 2 and P 2 O 5 ‐SiO 2 core light guides. Variations in composition profile shape with heat treatment were measured by an energy‐dispersive X‐ray analysis method. These data were fitted to a solution of Fick's second law to obtain diffusion data. No ch…