Materials Literature
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It has been suggested that the surface region of ordered liquids and, in particular, liquid crystals may extend well into the bulk phase.1 The surface tension of such materials could be expected to reflect changes in bulk properties and should be sensitive to mesophase transitions. In this study the surface tension of…
The Curie temperatures and the electrical resistivity at 4.2°, 78°, and 300°K have been measured for nickel-carbon solid solutions containing up to 1.5 at.% carbon. The resistivity at 4.2°K increases at the rate 3.48±0.06 μΩ cm/at.% carbon; whereas the Curie temperature decreases by ∼30 C°/at.% carbon. The electrical…
Crystalline hexamethylenediammonium adipate (m.p. 197 °C), the one to one salt of hexamethylenediamine and adipic acid, polymerizes at temperatures below its melting point yielding the corresponding polyamide (Nylon 66). Although there is considerable disorientation of the resulting crystalline polymer, two preferred…
Abstract The reactivities of boron, aluminium and silicon nitrides have been compared. Samples of these nitrides have been converted to oxides by being calcined in air. Changes in phase composition, surface area, crystallite and aggregate sizes have been correlated with oxidation time and temperature. Crystallites of…
ABSTRACT High-speed cinephotography has been used to study the movements performed by compound cilia from the segmental gills of Sabellaria and from the abfrontal face of the gill filaments of Mytilus. The two types of cilium have distinctly different beat patterns. Equations are derived which allow the calculation of…
The effects of gegenion on the polymerization of tetrahydrofuran (THF) indicated that the order of stability was PF 6 - ≃ SbF 6 - > BF 4 - ≥ SbCl 6 - . With all gegenions gel permeation chromatography indicated a rapid broadening of the molecular weight distribution before equilibrium conversion was reached. A narrowi…
The damping constant B for the viscous drag on dislocations was measured for NaCl and LiF. A novel technique was employed to improve the accuracy of the measurements, and many specimens were used to check the reproducibility of the results. Measurements of both the attenuation and velocity changes resulting from dislo…
Reflection coefficients of various order diffracted waves are calculated for an echelette grating which finds important use as a component of suboptical resonators. The classical optics approach has been found to be inadequate for deriving reliable results for this configuration. Accurate solution of the boundary valu…
Thin films of the rare-earth alloys of the Co–Sm system with and without the addition of Cu have been found to have exceptionally high coercive forces. A coercive force of 30 000 Oe was realized with Co3.65Cu1.35Sm films, 4000-Å thick prepared at a substrate temperature of 500°C using getter sputtering. This technique…
A number of binary systems have been investigated with p-n-dodecyloxybenzal-p-n-butoxyaniline—a mesomorphic component exhibiting both smectic and nematic phases—and other non-liquid crystalline solutes. When the transition temperatures of such binary systems are plotted against the mole per cent composition of the liq…
Abstract 1,3,3-Trimethylindolino-6′-nitro-benzopyrylspiran (1) exhibits a photoreversible color change which is called “photochromism”. However, it is transformed from a colorless form (A) into a colored form (C) which has a salt-like structure when acid such as malonic acid is added into acetone without irradiation w…
Summary Unit cell dimensions and refractive indices have been determined for synthetic pyroxenes in the system CaMgSi 2 O 6 -CaFeSi 2 O 6 -NaFeSi 2 O 6 , which have been crystallized and annealed on the nickel-bunsenite (Ni-NiO) oxygen buffer curve at 700 °C and a total pressure of 2 kb. The data presented confirms th…
A major constraint on the performance prediction of a hysteresis machine arises from the parasitic losses associated with the rotor magnetic material. These losses can be high enough to absorb much of the developed torque, particularly for small sizes and large numbers of poles. In this paper the phenomena which cause…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAddition of trichloromethyl radicals to alkenylsilanesHideki Sakurai, Akira Hosomi, and Makoto KumadaCite this: J. Org. Chem. 1969, 34, 6, 1764–1768Publication Date (Print):June 1, 1969Publication History Published online1 May 2002Published inissue 1 June 1969https://pubs.ac…
Atomic parameters in paramagnetic NiCl2·6H2O have been determined at room temperature from a single-crystal neutron-diffraction study in which the intensities of 100 independent reflections of the h0l and hk0 zones were measured. Isotropic least-squares refinement of the structure gave a final value of 0.104 for the r…
The electrooptic and ferroelectric properties of glass-ceramic systems containing Na0.5K0.5NbO3and BaTiO3as the crystalline phases are presented. Domain activity is observed by dielectric and optical hysteresis measurements, although it becomes significant only at the larger crystallite size. Thus, the samples transmi…
The nature of optically produced zone plates is briefly discussed in contrast to the conventional type of Fresnel zone plate. A rather simple method for generating zone plates is described, and some of the experimental results are given.
The heat capacity of colorless synthetic sapphire (α Al2O3, corundum) has been measured from 2 to 25 K. The data above 14 K can be expressed as Cv = 1.755×10−3T3+1.905×10−7T5 mJ/K·g-atom. This equation for Cv gives Θ0 = 1035 K, in good agreement with the values calculated from elastic constant data. An extrapolation o…
Optical investigations were performed to prove the idea of variable pitch in the Grandjean structure of cholesteric liquid crystals. According to this model, the helical structure is deformed in such a manner that with decreasing thickness of the wedge-shaped layer the pitch of the screw decreases, while the number of…
A 37-year-old married woman who had been suffering from rheumatoid arthritis for I 7 years was first seen in March, I967, complaining of intermittent diplopia for one month. When seen by the casualty officer she was found to have vertical diplopia in laevo-elevation, but surprisingly a Hess screen chart plotted the ne…