Preparation and Viscosity of Chitosans
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Materials Literature
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The surface tensions of liquid silicon and germanium were determined using the drop weight method. 600 dynes/cm was found for germanium and 720 dynes/cm for silicon at their freezing points and argon atmosphere. The parachors of the group IVb elements as derived from surface tension measurements of the molten elements…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of Nickel and Copper Impurities on the Recombination of Holes and Electrons in GermaniumJ. A. Burton, G. W. Hull, F. J. Morin, and J. C. SeveriensCite this: J. Phys. Chem. 1953, 57, 8, 853–859Publication Date (Print):August 1, 1953Publication History Published online1…
Summary The growth of tin whiskers is explained as a process in which oxidation of the whisker surface develops a stress which draws out a continuing thread of metal from the main mass. A mechanism is provided by a dislocation in the main mass which travels continuously around the root of the whisker. It then follows…
The fine structure of the nuclear magnetic resonance line in solid hydrogen at low temperatures (1.15\ifmmode^\circ\else\textdegree\fi{}K) was studied experimentally using a recording meter technique. The observed line shape can be explained quantitatively by the magnetic dipole interaction of the two protons in a hyd…
The corrosion resistances of several high-strength low-alloy steels in various atmospheres, in natural waters and in soil are compared with those of structural copper steel and structural carbon steel in the same environments. The effects of the many variables that influence the corrosion of these steels in the differ…
(1953). 24—THE GENERAL CASE OF FRICTION OF A STRING ROUND A CYLINDER. Journal of the Textile Institute Transactions: Vol. 44, No. 8-9, pp. T359-T362.
In this paper the properties of knitted fabrics, which will have to be known accurately and preferably quantitatively, before the design and specification of knitted structures for specific purposes is possible, are discussed. The load-extension characteristics of plain and ribbed structures are considered together wi…
The equilibrium curve for two of the phases of CaCO3, calcite-aragonite, has been determined as a function of temperature and pressure over the range 25–80°C and several thousand kg/cm2, using the electrical conductivity of aqueous solutions of each form. Aragonite is proved to be the high pressure modification. From…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxidations with Ruthenium TetroxideCarl Djerassi and Robert R. EngleCite this: J. Am. Chem. Soc. 1953, 75, 15, 3838–3840Publication Date (Print):August 1, 1953Publication History Published online1 May 2002Published inissue 1 August 1953https://pubs.acs.org/doi/10.1021/ja0111…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSegregation of Impurities During the Growth of Germanium and SiliconR. N. HallCite this: J. Phys. Chem. 1953, 57, 8, 836–839Publication Date (Print):August 1, 1953Publication History Published online1 May 2002Published inissue 1 August 1953https://pubs.acs.org/doi/10.1021/j1…
Abstract Recent experiments have indicated that the diffusion properties of a penetrant‐polymer system may change with time as diffusion proceeds. It is thought that two possible explanations of these time effects are slow changes of polymer structure accompanying diffusion and internal stresses exerted by one part of…
The average coefficients of thermal expansion of hexagonal zirconium between 298°K and 1143°K are 5.5×10−6 deg−1 along the a axis, 10.8×10−6 deg−1 along the c axis, and 7.2×10−6 deg−1 for a randomly oriented polycrystalline sample. The average value of the linear coefficient of expansion of cubic zirconium between 114…
It is known that the Curie point $\ensuremath{\theta}$ of the ferroelectric BaTi${\mathrm{O}}_{3}$ shifts to higher temperatures when a dc bias field is applied. If the crystal shows a sharp transition, we expect by applying an ac field at the Curie temperature that the crystal would become alternately ferroelectric a…
Summary Substitutional solute atoms in aluminium usually diffuse too slowly to cause appreciable strain ageing at room temperature. However, if the concentration of vacancies is increased by plastic deformation or by quenching, the rate of diffusion may increase sufficiently to cause strain ageing during plastic defor…
In the process of developing an atomic beam light source for use at high oven temperatures an investigation of the indium resonance lines at 4511A and 4101A was carried out. The employment of a well-collimated atomic beam, excited by electron impact, and of a Fabry-Perot interferometer made it possible to resolve clea…
Abstract The amount of energy stored in a cold-worked material is calculated on the assumption that the energy is due to piled-up groups of dislocations. It is found that a small percentage of the work done in deformation is stored, and that the amount of energy stored is proportional to the strain. These predictions…
Abstract Calculations from published figures of the equilibrium constants for the decomposition 2HNO 3 H 2 O + 2NO 2 + 1/2O 2 show that the degree of dissociation of nitric acid vapour is quite considerable even at moderate temperatures and reaches 100% at 200° and 1 atmosphere pressure. The rate of dissociation has b…
An integral expression for the electrical conductivity of thin films in a longitudinal magnetic field is derived by an analysis of free electron trajectories in the film. This is evaluated in the limit of strong magnetic fields.
In transducer applications of ferroelectric ceramics it is standard practice to rely for the electromechanical response on retained polarization. This is practicable only for moderate driving amplitudes and sufficiently low temperature. At higher driving fields dielectric losses increase inordinately and lead to event…