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Diffusion fronts in samples containing grain boundaries are spike shaped. Velocity of spike advance and angle between spike and boundary are measured. The "spike-velocity method" of analysis permits evaluation of two effective widths, ${W}_{D}$ and ${W}_{0}$, which describe the diffusion properties of the boundary. Th…
The lattice vibration spectrum of a solid can be characterized by one single frequency, which is defined as "the frequency of the center of gravity" of this spectrum or simply "center frequency." From its equality with the characteristic frequency of specific heat we have recently derived the "center law of the lattic…
Optical absorption cross sections and the fluorescent quantum efficiency in ruby have been determined. This data has been used to correlate calculations with the analysis of the preceding paper. Stimulated emission from ruby under pulsed excitation has been studied in some detail; the observations are found to depend…
Abstract Natürlich vorkommende organische Substanzen sind vielfach nach gewissen Regeln, Gesetzmäßigkeiten, gebaut. Solche Bauregeln sind nicht nur zur Konstitutionsaufklärung neuer Naturstoffe nützlich, sondern können, wie hier gezeigt wird, auch bei der Erforschung biochemischer Umsetzungen als Leitfaden dienen. Aus…
The safety problems of research reactors are discussed. Safety of these reactors depends principally from the rahin them, and the penetrating radiations emitted. The safety requirements for reactivity containments, control instruments and mechanisms, guaranteed supplies, and operations of the research reactors are des…
An approximate heuristic expression for the particle self-shielding factor for a set of purely absorbing spheres of radius r and volume fraction V well mixed with another set of non-absorbing spheres has been derived.The resulting expression has been experimentally verified using transmission data at several incident…
Abstract The ionic polymerization of octamethylcyclotetrasiloxane (the tetramer) proceeds through successive additions of tetramer on active centers. The active centers consist of the ion‐pair magnified image (where M stands for Na, K, Rb, Cs, Me 4 N−, Bu 4 P−, etc.) formed through the reaction of the hydroxide (oxide…
Abstract It is known that the thermal stability of polydimethylsiloxane is adversely affected by the presence in the siloxane polymer of active chain ends (i.e., by residual catalyst). The presence of catalyst causes the degradation reactions to proceed through an ionic mechanism (as opposed to the free‐radical mechan…
Stress-strain curves at rates of straining up to 440,000%/min. have been obtained for a number of textile yarns by a technique involving high-speed photography of the yarn following transverse impact. These curves and others obtained at conventional speeds are presented for samples of acetate, triacetate, cotton, poly…
Abstract It is known that maleic acid is partially and completely converted to fumaric acid, or its ester, on esterification. This phenomenon has a great practical importance, especially for unsaturated polyesters, because of the properties of the maleates, notably their reactivity during copolymerization, where their…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Preparation and Properties of Silyl Methyl Ether1Burt Sternbach and Alan G. MacDiarmidCite this: J. Am. Chem. Soc. 1961, 83, 16, 3384–3388Publication Date (Print):August 1, 1961Publication History Published online1 May 2002Published inissue 1 August 1961https://pubs.acs.…
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text D. W. Angel, W. R. Hunter, R. Tousey, and G. Hass, "Extreme Ultraviolet Reflectance of LiF-Coated Aluminum Mirrors," J. Opt. Soc. Am. 51, 913-914 (1961…
An expression is found for the force required to move a dislocation steadily through a visco elastic medium, in particular Zener's standard linear solid. It is applied to the case of a screw dislocation in iron exhibiting the Snoek effect. Sohoeok and Soeger'e atomic treatment of the same problem contains an error. Wh…
excellent description of the delicate tubular structure which invests each striated muscle fiber, and is especially replete with elaborate sketches of various muscle fibers from a comparative point of view. Subsequently many papers have been published using the light microscope in conjunction with various histological…
Single crystals of sodium nitrite were irradiated with Co60 gamma rays at 77°K and studied by the paramagnetic resonance method. An anisotropic three-line hyperfine spectrum associated with a single paramagnetic species was observed. The hyperfine structure arises from a nitrogen nucleus in the paramagnetic species at…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPHASE EQUILIBRIA IN THE BINARY SYSTEMS PuCl3—RbCl AND PuCl3—CsCl1R. Benz and R. M. DouglassCite this: J. Phys. Chem. 1961, 65, 8, 1461–1463Publication Date (Print):August 1, 1961Publication History Published online1 May 2002Published inissue 1 August 1961https://pubs.acs.org…
Abstract Aus den IR‐ und R AMAN ‐Spektren von Na 2 S 2 O 7 und K 2 S 2 O 7 wird mit Hilfe der Auswahlregeln für das S 2 O 7 ″‐Ion eine Struktur der Punktgruppe C 2v abgeleitet. Die beobachteten Frequenzen lassen sich größtenteils den Normalschwingungen zuordnen. Aus den erhaltenen Kraftkonstanten errechnet sich nach d…
Self-diffusion coefficients of crystal-bar zirconium have been measured between 1500 °C and 1100 °C, using radioactive Zr 95 as a tracer. The results may be represented by[Formula: see text]The pre-exponential factor is about three orders of magnitude smaller than that measured in most close-packed systems and the act…
The diffusion of nickel into grain boundaries of various tilt angles in copper bicrystals was studied. The concentration contours from the grain boundary and the lateral lattice diffusion were measured by means of electron-probe microanalysis. The product of grain-boundary width and diffusion coefficient were calculat…
The theory of the propagation of sound in a homogeneous gas including the effect of heat conduction is presented for the purpose of clarifying the underlying thermodynamic process. The propagation of sound in a liquid with a homogeneous and isotropic distribution of gas bubbles is then considered. The bubbles are assu…