Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The two charge density wave (CDW) transitions in 4H b TaS 2 have been followed under pressure. The two transition temperatures were lowered when pressure was applied; the 315K atmospheric pressure transition associated with CDW formation in the octahedral layers was suppressed by 35 kbar, the 22K transition associated…
The 423K phase transition of CsCuCl 3 is attributed to a cooperative Jahn-Teller effect. Using results of the group-theoretical analysis of phonon modes, it is shown that helical atomic displacements in the low-temperature phase can be represented by a suitable linear combination of the polarization vectors of the Jah…
When a smetic-$A$ phase is composed of chiral molecules, it exhibits an electroclinic effect, i.e., a direct coupling of molecular tilt to applied field. The pretransitional behavior of the electroclinic effect in the $A$ phase is used to study the critical behavior near the second order, smectic-$A$---smectic-$C$ pha…
Triclinic crystals of hen egg-white lysozyme cross-linked with glutaraldehyde have been treated with various denaturants and found to be susceptible to x-ray structure analysis even after major conformational changes in the protein. Cross-linked crystals were isomorphous with the native form, and electron density diff…
Abstract The morphology of heterogeneous blends of polybutadiene (PBD) and EPDM was selectively varied by a change of either the rheology of the blend components during mixing or of the blend composition. Under a given set of mixing conditions, the blend system approaches a “steady state morphology”, which was found t…
Cross-linked triclinic lysozyme was denatured with sodium dodecyl sulfate. Removal of the denaturant resulted in a refolding of the protein to a conformation similar to but not identical with the native one. Three-dimensional x-ray diffraction data out to 3.2-A resolution were collected for two states in the refolding…
Abstract The reinforcement of elastomers by carbon black is governed by the morphology of the black and its physical and chemical interactions with the polymer. The latter are strongly affected by graphitization and surface oxidation. In modern rubber‐grade carbon blacks strong bonding of the polymer to the carbon bla…
We illustrate the usefulness of the extended x-ray absorption fine-structure effect for determining the chemical state, structure, and location of adsorbed species by a study of 0.2 monolayers of bromine adsorbed on graphite at room temperature. Bromine adsorbs as molecules with one atom fixed above the basal-plane he…
Abstract Mother of pearl, or nacre, is one of a number of characteristic skeletal structures of molluscs, occurring in cephalopods, gastropods and bivalves. It consists of plates of aragonite, about 0.3 μm thick, arranged in sheets, with a tenuous protein matrix. Mechanical tests of nacre from all three classes show t…
A contribution to the magnetic anisotropy of evaporated films by an anisotropic mechanical stress caused by the substrate has been examined. Ni, Co, 85%Ni–Fe alloy with negative magnetostriction and 54%Fe–Co alloy with positive magnetostriction are evaporated onto X -and Z -cut quartz, and glass substrates. An anomalo…
"Random Processes in Nuclear Reactors." Nuclear Science and Engineering, 62(4), pp. 773–774
Acicular single domain particles of γFe2O3, treated with cobalt hydroxide (cobalt-adsorbed type) have more stable magnetic properties than ordinary cobalt-doped particles of γFe2O3. Their small temperature dependence of coercive force and stable uniaxial characteristic are comparable with those of particles of γFe2O3.…
Polybenzimidazoles were prepared in poly(phosphoric acid) from isophthalic acid (I), terephthalic acid (T), and 3,3′-di-aminobenzidine tetrahydrochloride dihydrate (DAB). Homo-polymers of I, T, and various IT copolymers have been prepared. The polymers were characterized by viscosity, IR spectra, and nitrogen estimati…
The objective of this research was to determine if a relationship could be found between dielectric strength and other properties of electrical insulating materials on an empirical basis by using variables predicted by basic theory.
The atomic scattering factors of aluminium have been measured at 80 K using powder samples. The results confirm earlier measurements at room temperature and are in agreement with theory by Ascarelli and Raccah.
A useful method of preparing ferrites has been developed by the coprecipitation of preferred combinations of metal carbonates and hydroxides. These combinations give powders of predictable compositions, low impurity levels and optimum particle sizes and reactivities. Some of the variables which are controlled are pH,…
Abstract Hydroxyl orientation has a major influence on the strength of the ionic interlayer bonding in micas because of the strong repulsion between the hydrogen and the interlayer cation (IC). In order to determine if other factors also influence the magnitude of the interlayer bond energy, the effect due to the vary…
Die ersten Acylisocyanide sind jetzt synthetisiert worden. Die hohe Carbonylaktivierung von Benzoylisocyanid (1) zeigt sich u. a. in der Acylierung von Inaminen; mit Acetylendicarbonsäureester reagiert (1) dagegen unter Cycloaddition. equation image
The method of self-consistent phonons is applied to the melting of the interchain phase locking of linear CDWs. The melting point is obtained as T c =0.11( m * / m ) 1/2 θ t , where m * is the effective mass of the phase mode phonon and θ t is its transverse Debye temperature essentially equal to the phase locking ene…
Methods for measuring residual stresses and distortions in welded structures are described and initial results are given of a survey being carried out during manufacture of warship hull sections. The stresses are determined by measuring the elastic strain induced in the plate and stiffeners due to contraction of the s…