Materials Literature
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A series of nematic liquid crystals which had been solvent recrystallized was further purified by use of the technique of zone refining. In all cases purity increased. Purity was determined using differential scanning calorimetry. Purity differences when the zone refiner was used at mesophase temperatures and isotropi…
Abstract A polybutadiene of high molecular weight was prepared in hydrocarbon solvent by using n ‐BuNa– tert ‐BuOM (M = Li, K) as a polymerization initiator. The microstructure of this polymer varied from 35 to 76% of 1,2 content, depending on the type of modifiers. The kinetics of polymerization was not studied, prim…
Abstract The hydrolytic degradation of poly(ester)‐urethanes (PUR) has been studied by viscometry of solutions of films that were treated for various times with water of fixed temperature. On the basis of some simplifying assumptions a general expression was derived relating the decay of the limiting viscosity number…
There is an apparent dearth of information concerning the chromosomes of the Appendicularia.A thorough search of the available literature has yielded only those observations summarized 8s follows : a diploid number of 6 for Oikopleura vanhoeaeni (SALENSKY, 1003) ; a diploid number of 7 of 0. rufescens (SALEXSKY, 1904…
Internal motions of polymer chains are classified into the local and the overall vibrations. The frequencies and modes of the latter are sensitive to the conformation of the chains. The discrimination between these two kinds of modes is explained, taking the 1,2-dichioroethane molecule as an example. The overall vibra…
The theoretical relation between the thickness of the oxide-layer and the oxidizing time was discussed in the case of oxidation of cylindrical and sliced copper to Cu2O in air at 990∼1045°C. Comparing the theoretical relation with experimental results, we obtain D=0.060exp[−(1.46±0.18)(eV)⁄kT] (cm2/sec) for the cylind…
Reaction of cobalt(II) phthalocyanine (CoPc) with thionyl chloride and with bromine leads to the formation of CoPcCl2 and CoPcBr2, respectively; magnetic i.r., oxidative titration, and e.s.r. data indicate these complexes to contain a phchalocyanine radical species, characterised in the solid state for the first time.
Thermal decempesition of Na, Mg, K, Ca, Mn, Co, Ni, Cu, Zn, Sr, Cd, Ba and Pb formates were investigated by use of gas chromatography and thermogravimetry.(1) Upon the decompositions of Na, Mg, K, Ca, Mn, Zn, Sr, Cd and Ba fermates, H2, CO and CO2 were formed as the main gaseous products, together with small amounts o…
Synopsis-A quantitative method for measuring and comparing the effect of various cos-metic treatments and products on the amount of FORCE needed to COMB a tress of HAIR is described. Photographs of the apparatus and a detailed description of the experi-mental procedure are provided. The results of several experiments…
The kinetics of desorption of surface oxide as CO and CO2 from graphite have been followed, using a mass spectrometer system, allowing their activation energies of desorption to be measured as a function of the amount desorbed. After the initial degassing of the graphite, surface oxide was reformed by chemisorption at…
Hydrogen overpotential on zinc uniformly alloyed with 500 ppm Cd, Fe, Ca, and Mn, as well as 200 ppm Hg, were measured in at room temperature. Exchange current densities and transfer coefficients for each alloy for the hydrogen evolution process were obtained. Except for Cd, all the other impurities including Hg will…
The emission characteristics of phosphors based on alkaline earth tellurates as host lattice are described. The fluorescence of hexavalent uranium in compounds of the formula M n TeO 3 + n with n = 2 or 3 , was studied. The spectral energy distribution of the fluorescence is affected by the cationic species and crysta…
The nucleation and growth kinetics of voids and interstitial dislocation loops in irradiated metals is theoretically considered. Taking into account a slight dependence of void swelling on the void concentration the void and dislocation loop nucleation rates are approximated by expressions allowing an analytical treat…
Photographic Techniques for Optical Microscopy and Macroscopy.- Specimen Preparation Methods for Microstructural Analysis.- Quantitative Stereology for Microstructural Analysis.- Devices for Quantitative Analysis.- Scanning Electron Microscopy for Microstructural Analysis.- High Voltage Electron Microscopy for Microst…
Abstract Two methods for the determination of oxalic acid were collaboratively studied. In both methods, the oxalic acid in spiked and unspiked spinach is precipitated as calcium oxalate from a buffered (pH 4.0–4.5) solution. The precipitate is separated from the solution by centrifuging 15 min at 1700 rpm. The oxalic…
The enthalpies of formation from Na(s) and WO3(s) of two cubic phase sodium tungsten bronzes. Na0·53WO3(s) and Na0·77WO3(s), have been determined by solution calorimetry. The thermodynamic stability of the cubic phase towards oxidation and disproportionation is discussed.
The reactions occurring during the anodic polarization of tinplate passivated cathodically in a dichromate solution (CDC tinplate) were ascertained by applying Faraday's law to analyses of the oxidation products generated. It was found that a large portion of the CDC passivation film consists of chromium in the metall…
A review of studies of photoconductivity in the ferroelectric-semiconductors SbSI and BaTiO3 is given and the results are discussed. In the short wavelength region of the spectrum there is an “extrinsic” photoconductivity of the ferroelectric due to the effect of the strong surface electric field on the nonequilibrium…
Abstract Die Isomorphiebeziehungen bei den Heptahydratsulfaten von Mg 2+ , Zn 2+ , Ni 2+ , Fe 2+ und Co 2+ werden untersucht. Es wurde festgestellt, daß wenn die Endglieder der betrachteten isomorphen Reihen in gleichen Strukturen kristallisieren, eine lückenlose Reihe der Mischkristalle existiert. Wenn die Endglieder…
Crystals of the title adduct are triclinic, space group P, with a= 14·347 ± 0·004, b= 13·194 + 0·002, c= 9·461 ± 0·001 Å, α= 72·50 ± 0·02, β= 114·70 ± 0·01, γ= 114·12 ± 0·02°, Z= 2. The structure was refined by least-squares methods to R 0·047 for 2829 observed intensities measured by diffractometer. The analysis show…