Materials Literature
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A rotating-analyzer technique for measuring the optical birefringence in liquid crystals is described. This apparatus is continuously readable and has excellent sensitivity. For a sample 50 μm thick, the apparatus has a resolution in the change of birefringence of 4 × 10−6, corresponding to a temperature change of 1 m…
Abstract The effect of shear on polymer crystallization kinetics has been studied for three materials at several shear rates and degrees of supercooling. Two poly(ethylene oxide) samples, with molecular weights of 72, 200 and 12, 600, and a poly(e‐caprolactone) material, with a molecular weight of 9, 400, were investi…
Phase relation studies of Si 3 N 1 , SiO 2 , and MgO have established three important subsolidus tie lines, viz. Si 3 N 4 ‐MgO, Si 3 N 4 ‐Mg 2 SiO 4 , and Si 2 N 2 O‐Mg 2 SiO 4 for nonoxidizing fabrication conditions. Strength measurements at 1400°C show that optimum strengths are obtained for compositions approaching…
Mixtures of terminal polar with terminal non-polar nematic liquid crystals usually produce induced smectic phases (ISP). This is shown by the investigation of a great number of systems using the contact method.In general, SA phases are induced. By means of X-ray investigations SB and SE phases were also established. N…
Multiphase caulytic packed-bed reactors are used in chtmid, petrocbemid, as well as in the petroleum Lndustrg for contactirrg gaseau and liquid reactaxzzs with 2 solid ucalyst. Xydrodesulfurszltion of petroleum fractions, liquid-phase catalytic hydrocracking, and brrryaadiol synthesis fmm forrmldehyde and acetylene (o…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of Molecular Weight on Excimer Formation of Polystyrenes in SolutionTadahiro Ishii, Takashi Handa, and Satoru MatsunagaCite this: Macromolecules 1978, 11, 1, 40–46Publication Date (Print):January 1, 1978Publication History Published online1 May 2002Published inissue 1…
The compound erroneously reported as NN-bis(chloromethyldimethylsilyl)acetamide has been proven by single-crystal X-ray analysis to be (O–Si)-chloro-[(N-chlorodimethylsilylacetamido)methyl]dimethylsilane.
Abstract Manganese and cobalt ferrites were prepared by the air oxidation of aqueous suspension of Fe(OH)2 and either Mn(OH)2 or Co(OH)2 at 50–80 °C. In alkaline suspensions, all the metal ions are transformed into spinel ferrites, MxFe3−xO4 (M=Mn or Co), by a suitable combination of the oxidation temperature and the…
Use of tannic acid (TA), in sequence with ferric chloride, uranyl acetate or gold chloride resulted in staining of selective but sometimes different sites in paraffin sections. TA-uranyl acetate of TA-ferric chloride stained sites rich in complex carbohydrates, wherease TA-gold chloride stained the collagen of various…
The effect of aging on the temperature dependence of permittivity ( K ) and tan δ as a function of frequency was examined for both ferroelectric and antiferroelectric PLZT compositions. All compositions aged near their transition temperatures exhibited a marked decrease in dispersion between the aging temperature and…
The forced Rayleigh light scattering technique has been applied to measurements of thermal diffusivity in liquid crystalline phases. In the nematic phase of p-methoxy benzylidene p-n-butyl aniline (MBBA), our results are in good agreement with the data obtained by classical methods. The thermal diffusivity anisotropy…
(1978). Physiological indicators of nutrient deficiency in algae. SIL Communications, 1953-1996: Vol. 21, No. 1, pp. 34-41.
Liquid Crystalline Phenyl‐trans‐4‐n‐alkylcyclohexanecarboxylates The syntheses of p‐substituted phenyl‐trans‐4‐n‐alkylcyclohexanecarboxylates 1 – 12 and cyclohexyl‐p‐n‐alkylbenzoates 15 – 17 and their mesomorphic properties are described. p‐n‐Alkoxyphenyl‐trans‐4‐n‐alkylcyclohexanecarboxylates 1 – 8 exhibit larger the…
Three test methods for determining degree of sensitization in austenitic stainless steels have been investigated. The results clearly show that all three test methods are capable of detecting moderate-to-severe degrees of sensitization, but the electrochemical potentiokinetic reactivation technique is the most sensiti…
The generalized de Gennes model for the nematic to smectic-$A$ phase transition in liquid crystals with an order parameter with $\frac{n}{2}$ complex components is investigated using the $\ensuremath{\epsilon}$ expansion in the vicinity of four dimensions. It is found that anisotropic critical behavior with correlatio…
Comparative investigation of the process of the structure reordering of disordered implanted silicon layers after thermal (800°C, 30 min) and pulse laser annealing have been carried out. The new laser method of annealing implanted layers has a number of interesting features which provide great efficiency and locality…
To clarify the nature of the ferromagnetic interactions in SrRuO 3 , the Ru 4+ – –Ru 4+ exchange couplings in cubic-perovskite type ARu 4+ O 3 (A=nonmagnetic cation.) were investigated. Magnetic measurements were done on these sample oxides (including single crystals of CaRuO 3 ) by using a magnetic balance technique.…
The processes that occur at grain boundaries during high temperature creep at low strain rates have been studied by scanning electron microscopy of a fiducial grid and by transmission electron microscopy mainly of pure aluminium. These and other observations are interpreted in terms of a dislocation model for grain bo…
LALS is a computer program for the refinement of molecular structures. It is primarily intended for helical macromolecules but has applicability in other fields. The refinement uses as data, X-ray structure factors, usually from fibre diffraction studies, and/or stereochemical information, including a comprehensive sh…
Data are presented on the thermomechanical response and electrical conductivity of two commonly used epoxy materials, Narmco 5208 resin and RB 398 adhesive, as a function of increasing temperature. The overall conformity of the results shows that the second-order Ehrenfest-type glass transition temperature, designated…