bluuebunny/crossref_metadata_2025 huggingface dataset:
Isobaric Spin without Charge Space
Authors: Bayman B. F.
Published: August 2005

The familiar consequences of charge-independence of a nuclear Hamiltonian are derived without introducing the concept of charge space and the extended Pauli principle. Ordinary wave-functions, separately antisymmetric in their protons and neutrons, are used throughout. This has the pedagogical advantage of emphasizing that the physical regularities associated with isobaric spin are consequences of charge-independence alone, and do not depend upon the charge-space formalism.
Counting Photons in the Optical Barrier Penetration Experiment
Authors: Coon D. D.
Published: August 2005

A cooled photomultiplier is used to count photons which tunnel through the gap between two prisms in the optical barrier penetration experiment. The transmission is found to be an exponentially decreasing function of gap spacing over the range of spacings measured (̃3 to 9 wavelengths). Furthermore, the strength of the exponential fall-off is in good agreement with the prediction of classical electrodynamics.
Čerenkov Radiation
Authors: More Richard M.
Published: August 2005

A simplified method for computing the energy yield in Čerenkov radiation by a fast-moving particle is described. The formalism is applied to the Čerenkov radiation of an electron-positron pair.
Electromagnetic Analog of the Quantum-Mechanical Tunnel Effect
Authors: Hupert Julius J. , Ott Gary
Published: August 2005

An electromagnetic model of a “potential barrier” may be constructed from three sectors of waveguide, two outer sectors being filled with dielectric, the short inner sector air-filled. Using the mathematical analogy between the propagation data of the De Broglie wave and the wave inside a waveguide—above and below cutoff—it is demonstrated that, for a frequency of operation between the cutoff frequencies of the air-filled and the dielectric-filled waveguide, the air-filled section represents the potential barrier region. Thus the described apparatus, the construction of which has been carried out in full detail, enables the modeling of the tunnel effect experimentally and in a quantitative fashion.
Visual Observations of Low-Energy Electron Beams
Authors: Haneman D.
Published: August 2005

Electron beams of low energy (100–200 eV) and low current (<25 μA) are rendered visible by introducing appropriate quantities of mercury vapor, for example, by temporarily lowering a cooling trap. Paths of beams in the presence of objects are photographed.
Generalized Conversion of Electromagnetic Units, Measures, and Equations
Authors: Gelman H.
Published: August 2005

A formulation of electromagnetic theory in generalized units is used to derive a scheme which is capable of transforming the measures and units of any electromagnetic quantity, and of converting any electromagnetic formula between arbitrary systems of electrical units.
Comments on a Paper by Majorana Concerning Elementary Particles
Authors: Fradkin D. M.
Published: August 2005

An early paper (1932) by Majorana, that has received but scant attention, is reexamined in light of later developments. This pioneering paper constructs a relativistically invariant theory of arbitrary spin particles, develops and utilizes infinite dimensional representations of the homogeneous Lorentz group, and provides a mass spectrum for elementary particles. The relevance of Majorana's approach and results to later and current research is explained.
Applications of Nuclear Energy: A New Course for the Humanities
Authors: Ruby Lawrence
Published: August 2005

A course has been developed designed to acquaint the nontechnical student in the humanities with nuclear energy and its applications in many areas affecting human affairs. Course content includes atomic and nuclear structure, applications of radioisotopes, reactors, fusion research, nuclear explosives, and accelerators. Other than the relativistic transformations, the radioactive-decay law and the cyclotron equations are the only relations occurring of any complexity. Socio-economic considerations are treated briefly as they arise. Results are given of a questionnaire examining the extent of misinformation on nuclear energy matters.
Simple Pulsed Nuclear-Magnetic Resonance Spectrometer
Authors: Lowe I. J. , Whitson D.
Published: August 2005

A relatively simple, incoherent, variable frequency pulsed nuclear-magnetic resonance spectrometer is described. It uses mostly commercial units and can examine materials with T2's greater than 50 μsec.
Are Electrons Real?
Authors: Houston W. V.
Published: August 2005

Recent years have shown a revival of interest in the conceptual problem raised by the incorporation of quantum mechanics into physics. The problem is an old one, but the use of both waves and particles as visualizations of electrons has presented it in a new and acute form. Several observations based on the methods of quantum mechanics can be made. (1) The time development of an isolated system is completely determinate, as in classical mechanics. (2) A precisely defined quantum mechanical state is an eigenstate of some operator described in classical terms. The production of such a state requires a suitable large scale apparatus. (3) If the state is not precisely defined as an eigenstate, quantum statistical mechanics must be used. (4) The idea of measurement is of doubtful applicability in the analysis of idealized experiments, since the process of measurement destroys the identity of the object (an electron) whose properties are measured. Quantum mechanics may be viewed strictly as a method of describing, in classical terms, the behavior of large scale apparatus, although the use of visualizations with a properly conditioned intuition is probably essential to progress in the analysis of new phenomena.
Misinterpretation of Theories of Light
Authors: Sparberg Esther B.
Published: August 2005

The oversimplification of issues in the history of science leads to a misunderstanding of the nature of scientific progress. For instance, most texts and many histories of science have perpetuated the myth that the distinction between Newton's theory of light and that of Huygens was clear cut and simple. They have compounded their error by indicating that Foucault's experiment in 1850, where he found the speed of light to be slower in water than in air, was “crucial” evidence in favor of Huygens's theory, thereby “disproving” the corpuscular theory of Newton. The position is defended that the theories of Newton and Huygens did not represent simple opposites; Newton's theories on light have been frequently misrepresented; and Foucault's experiment was not a crucial one.
Elementary Boundary Value Problems
Authors: Kraus Alfred A.
Published: August 2005

The solution of a particular elementary boundary value problem is presented. A new set of orthogonal functions is needed. Their properties are discussed briefly. A comment is made about the number of independent solutions of a rth order equation in an n dimensional space. The number is rn and not r·n.
Derivation of Conserved Quantities from Symmetries of the Lagrangian in Field Theory
Authors: Boyer Timothy H.
Published: August 2005

A derivation of the conserved quantities arising from symmetries of the Lagrangian density under continuous transformations is reviewed with an eye to brevity and clarity. The derivation is sufficiently general to include virtually all cases of interest in field theory. Also covered is a separate and very short derivation which is valid only in the special case, frequent in quantum field theory, of internal symmetries where the transformations are independent of space-time. Some sources of confusion and error in the published accounts of the problem are noted.
Modified Version of the MIT Rutherford Scattering Apparatus for Use in Advanced Undergraduate Laboratories
Authors: Earl James A.
Published: August 2005

Modifications of the MIT Rutherford Scattering Apparatus (Apparatus Drawings Project No. 16) are described. These include (1) use of a self-contained circuit for amplifying, analyzing, and counting pulses from the scintillation detector and (2) interchangeable foil holders which aid in the determination of background effects and which permit studies of scattering from various foils to be made. A description of the experiment performed by students at the University of Minnesota is given.
Structure of Physical Theory
Authors: Collins R. E.
Published: August 2005

This essay begins with considerations of the relational structure of a set of variables taken to represent a conceptual universe. A plausible argument is used to establish the necessity for a statistical description of any nonstatic set of such variables. A particular statistical description is then constructed based on a partition of the set of variables into two statistically independent sets. This statistical description is then shown to yield equations formally equivalent to familiar equations of thermodynamics, quantum mechanics, and classical mechanics. This mathematical development is strongly suggestive of a unified way of looking at several divergent fields of physics.
Evolution of the Balmer Series
Authors: Banet Leo
Published: August 2005

The evolution of the Balmer Series has not been well understood because of peculiar historical circumstances. Upon review of earlier publications of spectroscopy, an analysis of Balmer's papers, and a study of biographical information on Balmer, a clearer picture results. Much of the background information used by the mathematician Balmer was conveyed by the physicist Hagenbach and can be traced to a contemporary textbook by the spectroscopist Kayser, published one year prior to Balmer's historic lecture. Since Balmer did not describe all of his mathematical steps, they were reconstructed, using Balmer's own statements as much as possible. Balmer's success in establishing the series is connected with his ability in handling graphic methods of analysis; he referred to such analysis in his earlier paper, later published a geometrical construction of the hydrogen-line series and a text on projective geometry.
Permutation Symbol Approach to Elementary Vector Analysis
Authors: Evett Arthur A.
Published: August 2005

A presentation is given, in its simplest and most useful form for applications to physics, of the permutation symbol approach to elementary vector analysis. It is hoped that the availability of such a presentation will encourage wider use of the method in introductory and intermediate college courses in physics and engineering.
Classical Theory of Optical Detection
Authors: Walther Adriaan
Published: August 2005

It is proved that the maximum amount of energy that can be extracted from an electromagnetic field by a small detector is given by the time integral of the squared-vector potential. It is further shown that a discussion of less than perfect detectors leads quite naturally to the concept of self-coherence.
Calculation of Order Parameters of Perfectly Ordered Cu3Auand CuZn, an Exercise in Number Theory
Authors: Hall George L. , Christy Donald O.
Published: August 2005

The scalar-indexed Warren-Cowley order parameters for the perfectly ordered Cu3Au and CuZn alloys are calculated with the aid of Waring's theorem from number theory. Cowley and Klein have incorrectly reported these parameters for Cu3Au as being one for even-order shells (of neighbors) and −13 for odd-order shells. We show that these parameters are equal to one for those shells with radius d(2k)12, k ≠ 4a(8b + 7), and −13 for those shells with radius d(2k + 1)12, where a, b, k are nonnegative integers and d is the radius of the first shell in the fcc lattice. For the ordered form of CuZn (beta brass), we find that the order parameters are one for those shells with radius d(k)12, k ≠ 4a(8b + 7), and minus one for those shells with radius (d/2)(8k − 5)12, where a, b are nonnegative integers, k is a positive integer, and d is the nearest distance between two like atoms. Five theorems proved in this paper are the basis for the preceding results and are also useful in the study of point defects in cubic crystals and in the study of ionic crystals. Formulas are given for the radii of the shells of lattice points about given points, both lattice and interstitial points, in cubic lattices.
Advanced Laboratory Experiments on Optical Pumping of Rubidium Atoms—Part II: Free Precession
Authors: Nagel Michael , Haworth F. E.
Published: August 2005

A student experiment with free precession of rubidium atoms is described which uses the simple apparatus for optical pumping experiments described in Part I of this paper. This experiment shows that an oriented ensemble of atoms may be treated as a macroscopic magnetized gyroscope.
Undetermined Multiplier Treatments of the Lagrange Problem
Authors: Goedecke G. H.
Published: August 2005

In the physics and mathematics literature there exist two undetermined multiplier treatments of the Lagrange problem of the calculus of variations. These two treatments yield different results, in general; although they are in agreement in several commonly treated special cases. It is shown herein that the method favored by most physics texts is incorrect in the case of nonintegrable differential constraints, while the method appearing in most books on the methods of mathematical physics and the calculus of variations is correct, in general.
Undergraduate Experiment on Thermal and Shot Noise
Authors: Earl James A.
Published: August 2005

Boltzmann's constant, the charge on the electron and the centigrade temperature of absolute zero are measured in the experiment described. Details of the apparatus, which has given good results in the hands of students and which can be constructed from standard electronic components, are given.
Kepler's Harmonics and his Concept of Inertia
Authors: Rosen Edward
Published: August 2005

Kepler's Harmonics of the Universe, the mature work in which he first enunciated his third law of planetary motion, was a consummation of some of his youthful ideas. He introduced the term inertia into physics and astronomy, extended its purview to the heavens, and contributed essential components to the fully developed concept of inertia.
Enumerating Neighbors in Diamond-Like Lattices
Authors: Ferris-Prabhu A. V. M.
Published: August 2005

A simple method is presented for locating sites in diamond-like lattices, and for obtaining the number and locations of their neighbors of arbitrary order.
Yang-Mills Groups and Fields
Authors: Dotson Allen C.
Published: August 2005

A review is given of the procedure by which the electrodynamic gauge group has been used as a guide in the construction of a more complicated gauge group, known as a Yang-Mills group. The field which plays, in this new case, a role analogous to that of the electromagnetic field is discussed. Reference is also made to several recent attempts to relate the quanta of such fields to some of the vector mesons of elementary particle physics.
Teaching Dirac Notation and Relations Among Systems of Units
Authors: Smith Paul A.
Published: August 2005

Today's physics students would profit by being introduced to Dirac's bra-ket notation prior to encountering it in the unfamiliar context of quantum mechanics. While the notation may fruitfully be used in dealing with dc circuit theory, vectors in three-space, and the inertial tensor; we here use it to facilitate the succinct presentation of the linear transformations which specify the relations among systems of units. With this theory the student may be introduced to bra-ket notation on familiar ground, gain some insight into the structure of systems of units, and acquire a tool for computing conversion factors between any two systems of units he may encounter or devise.
Origin of SU3 Symmetry in Elementary Particles
Authors: Sen P.
Published: August 2005

The similarity between the energy density tensors of an isotropic harmonic oscillator and an isolated tube of fluid indicates that they are equivalent models for the description of elementary particles. In the latter model the wave equation for quantization of masses of elementary particles is already known and is explicitly stated.
Demonstrations and Experiments at Liquid-Helium Temperatures
Authors: Salinger G. L. , Leitner A.
Published: August 2005

Equipment is described for lecture demonstrations and laboratory experiments on the effects of superfluidity of liquid helium and superconductivity. Special features are (i) local construction of most components including unsilvered glass Dewar vessels, and (ii) flexibility of use. Projection of demonstrations is possible by a specially designed projector, or by closed circuit television without special lighting.
An Application of Matrix Optics
Authors: Eakin David M. , Davis Sumner P.
Published: August 2005

It is often desired to trace a ray through an optical system where the straightforward application of the laws of reflection and refraction at every surface would require an unreasonable amount of calculational effort. It may be possible to handle such situations quite easily through the use of matrix methods. The simple problem of multiple reflections between two spherical mirrors provides a good illustration of the technique and the ease with which results are obtained.
Experiment in Rigid-Body Dynamics
Authors: Weltin Hans
Published: August 2005

Lenses from a surplus bomb sight are used in an inexpensive laboratory experiment, verifying the equation of motion of a steel ball oscillating on a spherical surface. Effects of damping upon the period, and such concepts as natural frequency, critically damped and overdamped motion, and forced vibration are also demonstrated.
Equations of State and the Second Law of Thermodynamics
Authors: Levitas Alfred D.
Published: August 2005

The problem of integrating the energy equation of thermodynamics to obtain the caloric equation of state is treated. Two integration procedures, differing in the amount of information required concerning the system isotherms, are obtained and applied to several simple systems. A necessary restriction on the functional form of the energy of a system is shown to follow from the character of the system isotherms. A unified derivation is given for three well-known equations of state.
Use of Computers in an Undergraduate Light and Optics Laboratory
Authors: Hartman Roger D.
Published: August 2005

With the current emphasis on computers in science and engineering, it is felt that the undergraduate of such disciplines should be introduced to the applications of the computer as early in his educational program as feasible. With this premise in mind, an IBM 1620 computer has been put to use in an undergraduate light and optics laboratory course, generally taken by sophomores and/or juniors. Several experiments that are performed in the laboratory, together with their respective computer programs, written for the 1620 in FORTAN II language, are presented.
Experiments in Teaching Captives
Authors: Crane H. R.
Published: August 2005

Experiments on a multisectioned noncalculus introductory physics course are described. The aims were to provide opportunity for individual instruction for those who wanted it, to increase student-to-student help, and to improve motivation. The idea was to achieve these aims through changes in the pattern of operation or the rules of the game, rather than through improvements in presentation or selection of subject matter. Further boundary conditions were that faculty time was not to be increased and that rigor was not to be lessened. New features tried were: the substitution of open-office sessions for half of the classes; a student self-help room; a weekly printed handout; extra credit paperback reading. Finite progress was made; in particular (in the author's opinion), a larger fraction of the students developed lively interest in the subject than had been the case previously.
“New Physics” and the Minnesota Conference on New Materials for Introductory Physics Courses for Science and Engineering Majors, 6–8 May 1965
Authors: Roll Peter G.
Published: August 2005

To review and publicize the materials produced for several new introductory physics courses, and to assess the experience gained in using them, the Commission on College Physics held a Conference on New Materials for Introductory Physics Courses for Science and Engineering Students on 6–8 May 1965, at the University of Minnesota. This paper presents a brief review of the historical origins and general characteristics of the three most important new courses—those developed at Caltech, Berkeley, and MIT. Reports by persons active in teaching these and other new courses are summarized briefly, with particular emphasis on the effectiveness of the new materials with students, and on problems which have arisen during their use.
Dispersion, Reflection, and Eigenfrequencies on the Wave Machine
Authors: Burgel B. A.
Published: August 2005

A simple theory of the Wave Machine (Bell Telephone Laboratories) is presented. It takes into consideration the discrete structure of the vibrating system. The dispersion relation and formulas for the reflection and the eigenfrequencies are derived. The phase velocities observed on a typical Wave Machine are compared with the calculated values.
Constraints in Particle Mechanics and Geometry
Authors: Davis William R.
Published: August 2005

The problem of determining explicitly the forces of holonomic constraints in particle mechanics formulated in Riemannian space is carried through in a general manner. It is shown that the so-called projection operator hji ≡ δji — ninj enters quite naturally in problems involving one equation of constraint constituting a Vn − 1 in the given Vn. In addition, the results of this paper go beyond the early work of Synge in this area, in that their detailed connections with certain elementary results of the mathematical theory of subspaces Vn − 1 in Vn are given, which provide further physical insight.
Acceleration Referred to Moving Curvilinear Coordinates
Authors: Groves Gordon W.
Published: August 2005

The Coriolis and other fictitious accelerations are derived in terms of general coordinate transformations and are expressed in tensorial form.
Mathematical Description of Magnetic Resonance for Spins that Move
Authors: Johnson Charles S.
Published: August 2005

Equations are discussed which describe magnetic resonance phenomena in the presence of spin transfers among a number of different magnetic environments. An elementary “derivation” is given for modified Bloch equations in both the differential equation and matrix forms. The introduction of rate terms into density-matrix equations is also briefly discussed.
Henri Poincare and Einstein's Theory of Relativity
Authors: Goldberg Stanley
Published: August 2005

Contrary to the opinion of some who have written on the history of relativity, the author argues that Henri Poincaré did not anticipate Einstein's special theory of relativity; but rather, that Poincaré was intent on an entirely different program—the perfection of the Lorentz theory of electrons. It is also suggested that Poincaré was not consistent in his use of the so-called “conventional” point of view.
Thermodynamics of the Adiabatic Expansion of a Mixture of Two Phases
Authors: Cowperthwaite M. , Ahrens T. J.
Published: August 2005

The thermodynamics of the adiabatic expansion of a mixture of two phases capable of interchanging heat and matter across the phase boundary is presented. The law of conservation of energy is applied to each phase considered as an open system and to the mixture of phases considered as a closed system. Expressions for the entropy production resulting from internal irreversible processes demonstrate the difference between adiabatic and isentropic changes and specify conditions under which the expansion of a closed two-phase system is isentropic. Three such possible isentropic processes are defined, and expressions are derived for the temperature-pressure-volume states achieved in them. The thermodynamic treatment is useful in studies of the adiabatic release of a shock-induced mixture of phases.
Quantum-Mechanical Time Operator
Authors: Razavy M.
Published: August 2005

A first integral of motion in classical dynamics which contains the time explicitly and is conjugate to the Hamiltonian is quantized. The resulting quantal operator is applied to study the time delay caused by scattering, and in a simple case the expectation value of this operator is obtained.
Study of Amplitude Jumps
Authors: Stockard Donald P. , Johnson Tracy L. , Sears Francis W.
Published: August 2005

When a nonlinear oscillator is driven by a periodic driving force (or torque) whose frequency is varied slowly, the steady-state amplitude may suddenly change in a discontinuous manner. Two pieces of apparatus are described for demonstrating this interesting phenomenon, whose existence does not seem to be well known.
Introduction to Holography
Authors: Givens M. Parker
Published: August 2005

Holography is treated in a manner suitable for inclusion in an undergraduate optics course. The student is assumed to understand the elementary treatments of interference and diffraction.
Symmetry Origin of Dynamics
Authors: Greenberg David F.
Published: August 2005

Examples from classical mechanics are used to illustrate a procedure by which dynamical information may be extracted from experimentally observed higher symmetries. Broken symmetries are also discussed.
The Stimulated Raman Effect
Authors: Bloembergen N.
Published: August 2005

This paper reviews the main experimental and theoretical developments in stimulated Raman scattering of light, which has been actively investigated since 1962. The effect cannot be discussed properly without paying attention to related nonlinear effects which include stimulated Brillouin and Rayleigh scattering, self-focusing of light, and modulation of the refractive index. The physical processes are emphasized and no encyclopedic survey of all the data and the research literature is attempted, but a brief historical account is added in the final section.
Two-Dimensional Analog to the Hydrogen Atom
Authors: Zaslow B. , Zandler Melvin E.
Published: August 2005

The Schrödinger equation is applied to a two-dimensional problem of two mass points, one with the charge and mass of an electron and the other with the charge and mass of a proton. Solution exists in closed form, and the result is compared with that for a three-dimensional hydrogen atom.
Dynamic Electromagnetic Model for Material Media
Authors: Paris D. T.
Published: August 2005

The polarization and magnetization vectors, P and M, are shown to represent volume densities of electric and magnetic dipoles, respectively, in the case of harmonic fields just as they do in the simpler case of stationary fields.
New Acoustic Doppler-Shift Experiments
Authors: Muldawer L. , Meiners H. F.
Published: August 2005

Several new acoustic Doppler-shift experiments have been developed to obviate previous difficulties in observing the effect and to allow quantitative measurements. The equipment involves loudspeakers placed at the ends of a rotating arm inside an insulated box and microphones in the walls of the box. The microphonic responses are then displayed on an oscilloscope. One method of Doppler-effect detection makes use of changes in the width of a wave as seen on the oscilloscope. Two other methods involve superposition of the signals from approaching and receding speakers. The resultant beat pattern provides an accurate and visually satisfying method. The effects of variations of the angular speed of the revolving speakers and of variation in the sound frequency can easily be observed.
Bose-Einstein Condensation of an Ideal Gas
Authors: Casher A. , Revzen M.
Published: August 2005

The well-known free Bose-gas condensation is described as a condensation into a coherent state. The analogy of the phase transition that occurs here with more transparent symmetry-breaking transition is demonstrated.
Classical Electrodynamics
Authors: Marx Egon
Published: August 2005

A Lagrangian formulation of classical electrodynamics without a a priori introduction of potentials is presented.
Physics of the SU(3) Symmetry Model
Authors: Ram Budh
Published: August 2005

The basic ideas of the SU(3) symmetry model of strongly interacting particles are explained in a manner that should make the presentation clear to anyone who has had a course in ordinary quantum mechanics.
Terms Obtained from Configurations of Equivalent Electrons
Authors: Tuttle E. R.
Published: August 2005

A simple method is given for finding the terms obtained from a configuration containing a number of equivalent electrons. This method is based entirely upon two facts: (1) the Pauli principle prevents any two electrons from having the same quantum numbers; and, (2) one and only one completely antisymmetric wavefunction can be constructed from any given set of allowed quantum numbers. Because of its simplicity, both in concept and in application, this system is well suited to presentation to undergraduate students of modern physics.
Resource Letter CR-1 on Cosmic Rays
Authors: Winckler J. R. , Hofmann D. J.
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter in some of the main subjects of interest. Comments and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Such communications should be sent to Professor Joel Gordon, Chairman, Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore physics courses; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material principally suited for senior, graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York, New York 10017. When ordering, request Resource Letter CR-1 and enclose a stamped return envelope.
Interpretation of Quantum Mechanics and the Future of Physics
Authors: Witmer Enos E.
Published: August 2005

This paper deals with the problem of the interpretation of quantum mechanics, the nature of physical theory, and the future of physics. First, the question of why there are so many different interpretations of quantum mechanics proposed and accepted by outstanding quantum experts is treated. This requires a discussion of the relation between physics and philosophy and drawing a distinction between a physical formalism and a physical explanation. The Copenhagen interpretation is considered, criticized, and found to be unsatisfactory in some respects. Finally, an interpretation that contains ideas from previous interpretations but which may itself be new, is proposed. Hopefully, this is superior to the previous interpretations. It has, I believe, the advantage of logical clarity. In the process of doing this, I introduce a theory of levels of physical theory, according to which microscopic physical theory, as it develops in successive stages, becomes more and more adaptable to explaining—or at least taking cognizance of—fundamental biological or ultimately psychological phenomena.
Polarized Nucleons
Authors: Barschall H. H.
Published: August 2005

An elementary description of polarization phenomena involving spin-1/2particles is given. With the aid of schematic diagrams, the relation between analyzing power and polarization is obtained. Single and double scattering by spin-0 nuclei and depolarization effects in the scattering by nuclei with spin are discussed. A brief treatment of polarization phenomena in reactions is presented.
Introduction to Geophysical Magnetohydrodynamic Resonances
Authors: Radoski Henry R.
Published: August 2005

Resonance of a confined plasma magnetized by a dipole field is a fundamental geophysical problem which, except for special cases, remains unsolved. As an introduction to the equations, formalism, and concepts to be encountered in the more difficult dipole case, the problem of resonance in a plasma magnetized by a monopole or, in general, radial magnetic field has been solved. The magnetohydrodynamic wave equation is derived, and its plane wave solutions are indicated. For the case of a radial magnetic field, both axisymmetric and nonaxisymmetric solutions are obtained. Finally, the concept of vibrating magnetic-field lines is derived and discussed.
The Scientific Career of Charles Glover Barkla
Authors: Stephenson Reginald J.
Published: August 2005

Charles Glover Barkla (1877–1944) was one of the early pioneers in x-ray research. His most important contributions were those showing that x rays could be polarized; that when x-rays were scattered by light atoms the number of electrons in the atoms was about half their atomic weight, and that when x rays were incident on heavy atoms these atoms emitted characteristic or fluorescent radiations, which he called the K and L series. He explained the latter in terms of the Rutherford-Bohr atom. For the discovery of the characteristic radiations, he was awarded the Nobel prize in 1917. Shortly before this time, he considered that he had discovered a new type of characteristic radiation which he called J radiation, later modifying the description to J transformation. Though a great deal of work was done on this J radiation, he was not really able to substantiate its existence. He essentially never modified his early ideas or apparatus, although important discoveries were being made in x rays by Bragg, Compton, Auger, and others.
Optics and Spectroscopy—An Upper-Division Course in Physics
Authors: George S.
Published: August 2005

The paper describes in detail an upper-division one-semester physics course in experimental optics and spectroscopy. It is felt that such a course would be of considerable importance for inclusion in the upper division curriculum. This may, to some extent, help bridge the gap between the introductory laboratory and experimental research.
Physical Quantities in Different Reference Systems According to Relativity
Authors: Gamba A.
Published: August 2005

The relativistic transformation of measurements from one observer S to another observer S′ is valid, of course, only when both observers are measuring the same physical quantity. What is the same quantity is, however, not a trivial problem in relativity. As a matter of fact, two different definitions have already been used in the literature, without realizing that they were not equivalent. Some of the pitfalls of such a confusion are discussed.
Dynamical Friction
Authors: Webster David L.
Published: August 2005

Although a basic assumption in Chandrasekhar's theory of the dynamical friction acting on a star in a cluster has been regarded as disqualifying his theory for adaptation to an electron in a plasma, it is shown here that a new adaptation, with recognition of a contrast between the effects of other electrons and of ions, leads to a good formula for the friction. That is, it leads to a formula agreeing with one which Sitenko and Chien deduced from the Fokker-Planck equation. Disagreements with certain other Fokker-Planck theories have been traced to definite errors in these theories. Finally, Chandrasekhar's assumption that the friction exerted gravitationally on the star is the same as if only one other star acted on this one at any one time has been re-examined; and relatively simple reasons have been found for the validity of the electrostatic equivalent of his assumption, even though great numbers of electrons and ions act on an electron in a plasma at any one time.
Li + d
6
Experiment
Authors: Anthony Lee S. , Duggan Jerome L.
Published: August 2005

An experiment has been designed for undergraduate educational use. Deuterons from a 150-keV Cockcroft-Walton accelerator bombarded a thin Li6 target, producing Li(d,p1)76Li*, Li(d,p0)76Li, Li(d,α)46He, Li(d,n1)76Be*, and Li(d,n0)76Be. Equipment utilized is of the type which is either in or available to many departments of modest size. Properly used, such equipment constitutes an educational tool, teaching current research methods at reasonable cost. To this end, protons, alphas, neutrons, and gammas from the above reactions have been examined in a manner designed to be most instructive. Alpha and proton energies have been measured as a function of laboratory angle, and compared with kinematic calculations. Absolute differential cross sections have been derived from these data. A spectrum has also been made of the gammas from Li(d,n1)76Be* and Li(d,p1)76Li*. Gamma-proton and gamma-neutron coincidences measurements have been used to verify energy-level assignments. Angular correlation of the observed alphas has also been studied to show conservation of momentum and the effects of center-of-mass motion.
Interference-Fringe Counting as an Aspect of the Doppler Shift
Authors: Bloch S. C. , Abare W. E. , Pidick G. E.
Published: August 2005

Experiments suggest that the effect observed with Manchester's microwave Doppler-shift apparatus may be interpreted as a counting of interference fringes. This fringe-counting frequency is the same as that obtained from the Doppler-shift lower beat frequency, and does not invalidate the use of the apparatus for velocity measurements. In reflection from a moving mirror, and other Doppler-effect experiments where interference is possible, fringe counting may be regarded as an aspect of the Doppler effect; the connection between the fringe-counting frequency and the Doppler-frequency shift is provided by the fact that a linearly time-varying phase is equivalent to a constant-frequency shift.
Quantitative Experiments in Electrostatics for the Elementary Laboratory
Authors: Jeffers Fred , Soules Jack A.
Published: August 2005

Electrostatic experiments can be performed successfully even in humid climates if precautions against surface moisture are taken. A generator capable of delivering charge at a fixed, reproducible potential is described. A commercial electrometer is used as a high-impedance voltmeter to permit various experiments involving static charges on capacitors. The electrometer permits the construction of a simple probe for exploring both the magnitude and the direction of an electric field. The transition to circuit electricity is made by experiments employing capacitor discharge.
Some Remarks Concerning the Phenomenon of Ambipolar Diffusion in Gaseous Discharges
Authors: Hoyaux Max. F.
Published: August 2005

The phenomenon of ambipolar diffusion is one of the most fundamental in the gaseous plasmas normally encountered in glow discharges and low-pressure arcs. In spite of its apparent simplicity, its manifestations outside of a few “classical” situations can be relatively complicated, and make it a difficult matter to treat with a sufficient degree of generality. The extensions to the case with an external electric field, to that of a noncylindrical positive column, to that of a plasma with a magnetic field are considered. A possible clue to the case of a weakly ionized, weakly magnetized plasma of noncylindrical form is suggested.
Use of the Characteristic Function in the Derivation of Liouville's Equation
Authors: Beran Mark J.
Published: August 2005

A derivation of Liouville's equation is given using the formalism employed by Hopf (1952) and Edwards (1964) in their derivation of the equations governing, respectively, the characteristic-density functional and probability-density functional associated with turbulent fluids.
Thermodynamics and Classical Relativity
Authors: Tykodi Ralph J.
Published: August 2005

The classical principle of relativity (invariance of the laws of motion to a Galilean transformation of coordinates) with its change of viewpoint from one coordinate system to another rarely comes into question in the routine sort of thermodynamic analysis. By analysis of the Joule-Thomson porous-plug experiment under various conditions, it is shown that the standard formalism of thermodynamics is consistent with the classical relativity principle.
Differentiating Unit Orthogonal Vectors in a Riemannian Space that Admits an N-tuply Orthogonal System of Hypersurfaces
Authors: Williams Gareth
Published: August 2005

In a normal coordinate system { ya } , the identity ∂2xp/∂yn∂ym = ∂2xp/∂ym∂yn is used to obtain expressions, involving the components of the metric tensor in this coordinate system, for the derivatives of the unit tangent vectors to the parametric curves. An example is given for a normal coordinate system in the De Sitter universe.
Resource Letter NR-1 on Nuclear Reactions
Authors: Griffy T. A.
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of Physics. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter in some of the main subjects of interest. Comments and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Such communications should be sent to Professor Joel Gordon, Chairman, Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore Physics courses; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material principally suited for senior or graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York, New York 10017. When ordering, request Resource Letter NR-1 and enclose a stamped return envelope.
Interference in Scattered Light
Authors: de Witte A. J.
Published: August 2005

Most interference experiments demand careful adjustment of the apparatus and special conditions of illumination for the phenomena to be at all observable. By contrast, the interference effects discussed here not only require no such precautions but are, in fact, almost unavoidable in any optical system that contains reflecting surfaces. For all their ubiquity, however, the phenomena are nonetheless elusive to the point that they seem to have become virtually unknown. Modern design of optical instruments may have eliminated much of this interference. In any case, the effects no longer appear to have practical interest and are relegated to obscurity. It was not always thus. Few subjects have attracted such a long line of luminaries in the literature of optics. This paper attempts to recapture some of the by-gone luster. It presents a review of the history and of the theory of the effect, illustrated by some measurements and photographs.
Anniversaries in 1967 of Interest to Physicists
Authors: Barr E. Scott
Published: August 2005

During the year 1967 there are major anniversaries of the births or deaths of one woman and eight men whose accomplishments and influence have been of importance to the development of physics. They are: Jean Victor Poncelet, Michael Faraday, Alexander Dallas Bache, William Allen Miller, Louis Winslow Austin, Marie Sklodowska Curie, Marie Paul Auguste Charles Fabry, Frank Lawton Olcott Wadsworth, and Walter Porter White. Brief accounts of their lives and achievements are given here.
Difference Equation to Approximate Schrödinger's in a Periodic Potential
Authors: Armstrong H. L.
Published: August 2005

When Schrödinger's equation is approximated by a difference equation in a periodic potential, such as that of the lattice of a solid material, it is easy to solve for the energies. Then energy bands, Brillouin zones, and effective masses can be illustrated; and the illustration in terms of three dimensions seems more nearly realistic than that in one.
Physics of Raman Lasers
Authors: Bhaumik M. L.
Published: August 2005

The physics of Raman lasers is described in simple terms. A simplified gain formula is presented for the threshold of Raman-laser action. The features of stimulated Raman scattering are compared with those of spontaneous Raman process. Finally, a review of the various cavities used for Raman lasers is presented.
Kinematics—Quaternions—Spinors—and Pauli's Spin Matrices
Authors: Kronsbein John
Published: August 2005

A simplified presentation of the relation between motion (space transformation) of a set of objects with spin and the induced (nonrelativistic) spinor transformation by development of quaternions from certain four-dimensional rotation matrices. These are interpreted as conformal transformations in three-space. Quaternions are essentially equivalent to Pauli spin matrices which can be generated by regarding a quaternion matrix as compound—i.e., a 2×2 matrix with 2×2 matrix elements. Explicit formulas with instructions for their use are given.
Logical Structure of the First Three Sections of Newton's Principia
Authors: Bork Alfred M.
Published: August 2005

The chart shown here pictures Newton's logical paths in the early material of Book 1 of the Principia.
Fraunhofer and the Great Dorpat Refractor
Authors: Waaland J. Robert
Published: August 2005

The Great Dorpat Refractor built by Joseph Fraunhofer and completed in 1824 was the first modern, achromatic, refracting telescope. At the start of the 19th century, progress in astronomy was stifled by the lack of astronomical quality telescopes of sufficient aperture and manageability. There were long-focus, nonachromatic refractors, reflectors with speculum metal mirrors, and achromatic refractors of small aperture and mediocre design. Contributing to the construction and success of the Great Dorpat Refractor were P. L. Guinand's development of a process for making large disks of homogenous flint glass, Fraunhofer's improvement of the design and fabrication of the optical and mechanical components of the telescope, and F. G. W. Struve's skilled and dedicated use of the telescope and its accessories. The successors of the Great Dorpat Refractor were the giant refractors which were the mainstay of astronomy in the 19th century and which were not displaced until the early 20th century when the age of the giant reflectors began.
Vacuum System for an Experiment on the Flow of Oxygen across a Silver Barrier and through a Capillary
Authors: Busen Karl M.
Published: August 2005

The continued growth of vacuum technology as applied to research and engineering makes it important that students become acquainted with a typical vacuum system. This article describes a system which can be applied to the determination of the quantity of gas flowing through a cylindrical tube and to investigations on the passage of gas across a solid barrier (process of permeation). The vacuum system has been designed in such a way that the experiment can be accomplished in a 2- to 4-h laboratory period.
Minority-Majority Notation for the Mathematics of Semiconductor Theory
Authors: Freeman J. R.
Published: August 2005

A minority-majority notation is introduced which is supplemental and complementary to the hole-electron notation used in the mathematics of semiconductor theory. Together, the two notations provide the flexibility of expression necessary to explain more clearly and appropriately the mechanisms of charge-carrier behavior in semiconductors. It is explained that equations formulated with the minority-majority symbology are the general forms, and thus the necessity of committing general analyses to the separate cases of either N- or P-type transport media is obviated.