Showing papers in "Physics Today in 1954"
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TL;DR: Forty-six standard x ray diffraction powder patterns were presented in this article, fourteen of which are to repace twelve patterns already given in the x ray Powder Data File, and thirty-four are for substances not previously included.
Abstract: Forty-six standard x ray diffraction powder patterns are presented. Fourteen are to repiace twelve patterns already given in the x ray Powder Data File, and thirty-four are for substances not previously included. The patterns were made with a Geiger counter x ray diffractometer, using samples of high purity. The d-values were assigned Miller indices determined by comparison with calculated interplanar spacings and from space group considerations. The densities and lattice constants were calcuiated, and the refractive indices were measured whenever possible. (auth)
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TL;DR: In this article, the Compton energy versus angle relationship and the differential and integral Klein-Nishina cross sections are presented graphically as functions of the energy and direction of the scattered photon and of the recoil electron.
Abstract: : The Compton energy versus angle relationship and the differential and integral Klein-Nishina cross sections are presented graphically as functions of the energy and direction of the scattered photon and of the recoil electron. These graphs are intended to serve the purpose of tables. Unpolarized primary gamma rays in an energy range from 10 Kev to 500 Mev are considered. The accuracy of all curves is estimated at 1 percent. The advantage of this form of presentation is the convenience and accuracy of two-way interpolation. In general, interpolated values may be obtained with an accuracy of 2 percent.
TL;DR: In this paper, a lecture in honor of Joseph Henry's genius was described as "a man of varied culture, of large breadth and liberality of views, of generous impulses and of great gentleness and courtesy of manner".
Abstract: Joseph Henry's genius was attracted primarily to the great experimental problems of his age. Although he was a professor of natural philosophy, a discipline which a century ago combined the various branches of physical science, he is not known to have indulged in the kind of formal considerations to which the title of this evening's discourse alludes. Yet I am confident that my subject is not wholly inappropriate to the occasion of a lecture in honor of Joseph Henry. For his eminent biographer, Charles Greeley Abbot, describes him as “a man of varied culture, of large breadth and liberality of views, of generous impulses and of great gentleness and courtesy of manner”. Hence, while the speculations on which I am about to embark can hardly aspire to honor his memory, we may take comfort in supposing that he would gracefully listen to them and accept them as a small token of respect.
TL;DR: In this paper, the authors considered lines of finite length with the voltage impressed on the line through a terminal impedance Z 1 and the distant end closed by a second terminal impedance X 2.
Abstract: So far in our discussions of wave propagation in lines and wave-filters, we have confined attention to the case where the impressed voltage is applied directly to the infinitely long line. We have found that, by virtue of this restriction, the indicial admittance functions of the important types of transmission systems are rather easily derived and expressible in terms of well known functions, and the essential phenomena of wave propagation clearly exhibited. In practice, however, we are concerned with lines of finite length with the voltage impressed on the line through a terminal impedance Z1 and the distant end closed by a second terminal impedance Z2. We now take up the problem presented by such a system.
TL;DR: The fourth edition of the International Conference on High Energy Nuclear Physics and Cosmonautics was held at the University of Rochester in the US in January 25-27, 2019 as mentioned in this paper.
Abstract: The conference on January 25–27 at Rochester demonstrated that considerable progress has been made in our experimental understanding of the fundamental properties of nucleons and mesons and their mutual interactions during the past year, but that theoretical insight into the meaning of these results still leaves much to be desired. This was the fourth in the series of annual conferences organized by Professor R. E. Marshak and jointly sponsored by a group of Rochester industries and the National Science Foundation. These informal sessions serve as a meeting ground for representatives from most American and several European laboratories actively engaged in high‐energy nuclear physics and cosmic‐ray research, and have proved extremely valuable both for clarifying the amount of progress already made and the outstanding problems yet to be solved. In view of the wealth of material discussed. I have singled out only a few topics for detailed discussion in what follows.
TL;DR: Several phenomena, essentially of chemical nature, which can cause a transportation of matter and radioactivity often occur in the handling of radioactive materials as mentioned in this paper, and it seems desirable to give wide notice to the phenomena for two reasons: first, since they occur most readily when large quantities of radioactivity are involved, close observation may be difficult or precluded; second, since many of the workers handling solid radioactive materials are engaged in physical experimentation rather than chemical, they might be led to an extensive and lengthy course of investigation before the proper explanation was discovered.
Abstract: Several phenomena, essentially of chemical nature, which can cause a transportation of matter and radioactivity often occur in the handling of radioactive materials. The problem of confining radioactivity is a practical one and is of itself a concern. But in addition, the measurements of mass and radioactivity are basic data in many scientific experiments and a transportation of matter and radioactivity can give rise to baffling or spurious experimental results. It seems desirable to give wide notice to the phenomena for two reasons: first, since they occur most readily when large quantities of radioactivity are involved, close observation may be difficult or precluded; second, since many of the workers handling solid radioactive materials are engaged in physical experimentation rather than chemical, they might be led to an extensive and lengthy course of investigation before the proper explanation was discovered.
TL;DR: In this article, the authors present a theory of complex variable functions of a complex variable and their integration under the integral sign under the sign of O(z) has branch points.
Abstract: Preface to the second edition Preface to the first edition Part I. Theory of Complex Variable: 1. Functions of a complex variable 2. Integration: Cauchy's theorem: Taylor's and Laurent's theorems 3. Calculus of residues 4. The Bromwich contour: equivalent contours: evaluation of integrals 5. Gamma, error and Bessel functions 6. Evaluation of 1/2 i Br1 ezto(z)dz/z when o(z) has branch points 7. Differentiation and integration under the integral sign Part II. Theory of Transform Calculus: 8. Mellin inversion theorem: transform theory 9. Solution of ordinary linear differential equations 10. Discontinuous functions: impulses: frequency spectra Part III. Technical Applications of Parts I and II: 11. Electrical circuits: vibrational systems: aeroplane dynamics: deflexion of beams 12. Radio and television receivers 13. Partial linear differential equations: electrical transmission lines: electrical wave filters 14. Solenoid with metal core: condenser microphone: loud speaker horn 15. Diffusion of heat: absorption of moisture problems to be worked out by the reader Part IV. Appendices and List of References Index.