bluuebunny/crossref_metadata_2025 huggingface dataset:
Residue energy and mobility in sequence to global structure and dynamics of a HIV-1 protease (1DIFA) by a coarse-grained Monte Carlo simulation
Authors: Pandey R. B. , Farmer B. L.
Published: January 2009

Energy, mobility, and structural profiles of residues in a specific sequence of human immunodeficiency virus (HIV)-1 protease chain and its global conformation and dynamics are studied by a coarse-grained computer simulation model on a cubic lattice. HIV-1 protease is described by a chain of 99 residues (nodes) in a specific sequence (1DIFA) with N- and C-terminals on the lattice, where empty lattice sites represent an effective solvent medium. Internal structures of the residues are ignored but their specificities are captured via an interaction (εij) matrix (residue-residue, residue-solvent) of the coefficient (fεij) of the Lennard-Jones potential. Simulations are performed for a range of interaction strength (f) with the solvent-residue interaction describing the quality of the solvent. Snapshots of the protein show considerable changes in the conformation of the protein on varying the interaction. From the mobility and energy profiles of the residues, it is possible to identify the active (and not so active) segments of the protein and consequently their role in proteolysis. Contrary to interaction thermodynamics, the hydrophobic residues possess higher configurational energy and lower mobility while the electrostatic and polar residues are more mobile despite their lower interaction energy. Segments of hydrophobic core residues, crucial for the structural evolution of the protein are identified—some of which are consistent with recent molecular dynamics simulation in context to possible clinical observations. Global energy and radius of gyration of the protein exhibit nonmonotonic dependence on the interaction strength (f) with opposite trends, e.g., rapid transition into globular structure with higher energy. Variations of the rms displacement of the protein and that of a tracer residue, Gly49, with the time steps show how they slow down on increasing the interaction strength.
Effects of viscosity in a partially ionized channel flow with thermionic emission
Authors: Mikellides Ioannis G.
Published: January 2009

The flow of the partially ionized gas inside thermionic hollow cathodes spans a diverse range of theoretical disciplines in plasma physics and fluid mechanics. Understanding and predicting the evolution of such flows has many practical implications because hollow cathodes are critical components of electric propulsion systems used onboard scientific and commercial spacecraft presently in space or in the mission planning stages. As space missions become more demanding of the propulsion system in terms of throughput, understanding and predicting failure mechanisms of the system becomes imperative. Two-dimensional numerical simulations of the partially ionized gas generated by a thermionic hollow cathode have been performed to quantify the effects of viscosity inside the cylindrical channel of the device. A comparison of the inviscid and fully viscous flow fields shows that viscosity has a significant impact on the atomic species and a lesser effect on the ions. The internal pressure is determined to be more than 40% higher compared to the inviscid solution and the Reynolds number for the flow of atoms is found to be less than 20 inside the channel. Although the Mach number is computed to be <0.1 for approximately 95% of the channel, the solution for the velocity flow field begins to deviate from the Poiseuille (parabolic) solution at about 50% of the channel due mainly to collisional drag with ions.
Excitonic versus electronic couplings in molecular assemblies: The importance of non-nearest neighbor interactions
Authors: Gierschner Johannes , Huang Ya-Shih , Van Averbeke Bernard , Cornil Jérôme , Friend Richard H. , Beljonne David
Published: January 2009

We demonstrate that for a range of phenylene- and thiophene-based conjugated polymers of practical relevance for optoelectronic applications, exciton couplings in one-dimensional stacks deviate significantly from the nearest neighbor approximation. Instead, long-range interactions with non-nearest neighbors have to be included, which become increasingly important with growing oligomer size. While the exciton coupling vanishes for infinitely long ideal polymer chains and provides a sensitive measure of the actual conjugation length, the electronic coupling mediating charge transport shows rapid convergence with molecular size. Similar results have been obtained for very different molecular backbones, thus highlighting the general character of these findings.
Color vision
Authors: MacAdam David L.
Published: January 2009

Tracing the working of any one of the human senses from a physical stimulus to its perception by man brings into play taxing problems which reach to the limits of knowledge in each of the sciences it touches. Vision—color vision—is a particularly complicated process to study. Physicists investigate light, how it is emitted, absorbed, reflected, and how it passes through space. Physicists and biologists study how it passes through the eye; biochemists, histologists, electrophysiologists, neurologists, and so forth, study how it is received by the nerve-sensitive retina and then passed on to the brain. Somewhere along the line the psychologist enters the fray.
Phase Relations in Hearing
Authors: Licklider J. C. R.
Published: January 2009

The two input channels of the human auditory system are connected together in a very special way.
Optical Society
Authors: B. S. S.
Published: January 2009

The winter meeting of the Optical Society of America, held at the Hotel Pennsylvania in New York City on March 4–6, may be best characterized in terms of the diversity of subjects covered in the fifty-six papers presented.
Italy
Authors: Amaldi E.
Published: January 2009

To understand the present status of physics in Italy, we must look back to the years when Italian physics became remarkably important through the work of such men as Fermi and Rossi.
Washington Letter
Authors: Trytten M. H.
Published: January 2009

Events of importance to science have been happening in Washington since the war in almost unbroken series. In some cases, the struggle for mutual understanding among scientists and politicians, administrators and military personnel may have its less happy aspects, but because of the great power of science in national and international affairs at the present time, some of this is inevitable. On the whole, considerable understanding is being achieved.
Netherlands
Authors: Gorter C. J.
Published: January 2009

The international physics meeting in Holland in July 1948 may attract a considerable number of physicists, and in view of this it seems worthwhile to sketch the organization of research in physics in that country. Fundamental research is centered in the laboratories of the three state universities at Leyden, Utrecht, and Groningen, and in the municipal university at Amsterdam.
Aerodynamics and Acoustics
Authors: Miles John W.
Published: January 2009

This paper illustrates that certain techniques common to acoustics and supersonic aerodynamics.
Science on the air
Authors: Pfeiffer John E.
Published: January 2009

It is a bare fact, whether or not one finds it an unhappy state of affairs, that a soap opera or a quiz show regularly attracts millions more listeners than a broadcast on any field of science. Naturally those responsible for putting broadcasts on the air shy away from the very word science in their program planning. The blame, of course, lies with radio for not devoting more time and energy to popularization—and with the scientists themselves for thinking too much about what they want to say and not enough about the people who are supposed to listen to it. It should surprise no one that the joint efforts of radio and the scientists have been so widely unheard.
Institute Doings
Authors: Barton Henry
Published: January 2009

The annual meeting of the Governing Board was held late in March.
College and University Chapters
Authors: Barton Henry A.
Published: January 2009

The Board was in accord with the feeling of individuals at various institutions that there are now enough physics students to merit the establishment of local chapters at colleges and universities, designed to foster interest and professional responsibility and to establish a first link to the Member Societies and the Institute.
Plasticity in Metals
Authors: Prager William
Published: January 2009

Two groups of theories have been proposed to explain the way metals harden when they are deformed at temperatures below that in which they undergo change in their crystal structure: they are the theories of plastic deformation and theories of plastic flow.
Irradiation Effects
Authors: Trump J. G.
Published: January 2009

The Massachusetts Institute of Technology has applied its particle-accelerating techniques to the study of the biological, photochemical, and germicidal effects of intense ionizing radiations.
Radiation and Rockets
Authors: Penner S. S.
Published: January 2009

The hot radiating gases formed during normal combustion in liquid-fuel rocket motors are responsible for radiant heat transfer to the chamber walls and to the liquid or gaseous reactants which are injected at the head end of the rocket chamber.
Institute Doings
Authors: Barton Henry A.
Published: January 2009

What goes on at the Institute? Some physicists will judge the organization by what it accomplishes and by the economy of its operation.
Distored Binocular Vision
Authors: Ogle K. N.
Published: January 2009

The two eyes observe objects in space from slightly different points of view and the slight differences in what the two eyes see localize the objects in space.
Magnetic Properties
Authors: Hutchison Clyde A.
Published: January 2009

In 1923 Niels Bohr predicted, on the basis of his theories of periodicities in the electronic structures of the elements, that somewhere near the end of the periodic table there should exist a series of elements similar to the rare earths.
Applied Mathematics
Authors: T. A. H.
Published: January 2009

Electromagnetic theory was under discussion at the Second Symposium on Applied Mathematics of the American Mathematical Society held at MIT on July 29–31. Papers were presented on the status of the new covariant formulation of quantum electrodynamics, reformulations of electromagnetic field theory along classical lines, the solutions of several types of boundary value problems related to the Maxwell field theory, methods of solving boundary value problems, orbit theory and its applications, the response of linear electrical networks, nonlinear electrical networks, the abstract formulation of problems in the communication of information, and on random noise.
Aligned Nuclei
Authors: R. M. E. , R. L. D.
Published: January 2009

The Oak Ridge National Laboratory Conference on Low Temperatures and Nuclear Physics, August 7 and 8, was held to foster an exchange of ideas between scientists in these two fields. Since the alignment of nuclear spins interested both groups, particular emphasis was given to this subject. The low temperature physicist is interested in it because through the use of aligned nuclei it may sometime be possible to obtain temperatures as low as one millionth of a degree absolute. The nuclear physicist is interested because the study of neutron scattering and capture by aligned nuclei will give information about the spin of the nuclear compound state, and about nuclear forces.
Faster than sound
Authors: Dryden Hugh L.
Published: January 2009

On October 14, 1947, Captain Charles E. Yeager, U.S. Air Force, became the first man to reach, in a piloted airplane, sustained horizontal flight at a speed faster than sound, marking the dawn of the supersonic age. Since that day many flights of the Bell XS-I research airplane have been made at supersonic speeds by Captain Yeager and two other Air Force pilots, Major G. E. Lundquist and Captain J. T. Fitzgerald, and by Herbert H. Hoover and the late Howard Lilly, research pilots of the National Advisory Committee for Aeronautics.
Take away your billion dollars
Authors: Roberts Arthur
Published: January 2009

The merry and somewhat irreverent comment on big operations in physics, which appears on the following pages, was first played at a small farewell party for Arthur Roberts just before he left Cambridge.
Magnetic Poles
Authors: Dirac P. A. M.
Published: January 2009

One of the most striking features of atomic physics is the fact that electricity always occurs in integral multiples of a quantum of electricity, the electronic charge.
Rockets and Meteorites
Authors: Grimminger G.
Published: January 2009

Rockets may possibly be made fast enough to reach equilibrium with the earth's gravitational field and revolve about the earth as satellites or to escape the earth entirely and travel in interplanetary space.
Instrument Show
Authors: Harrison George R.
Published: January 2009

More than thirteen thousand people came to see the exhibits of nearly two hundred manufacturers and to attend the technical sessions at the Third National Instrument Conference held in Philadelphia the week of September 13. Institute members who attended found their interest in instruments a means of introduction to many active engineering groups.
Investment in basic research
Authors: Piore Emanuel R.
Published: January 2009

The program of the Office of Naval Research was initiated in the fall of 1945, when scientists were returning to their peacetime pursuits and funds were required for this conversion from war to peace. The Office of Scientific Research and Development (OSRD) was liquidating its activities, and it was necessary to conserve some of the scientific assets created during the war. This problem was recognized by many people in high government, industrial, and academic circles. The Navy had the foresight to take action.
Women…in physics
Authors: Michels Walter C.
Published: January 2009

Female physics students are just as capable as their male counterparts.
Photographic Printing Control
Authors: Jones Loyd A.
Published: January 2009

In recent years photographic workers have shown an increasing interest in finding a way to predict the best possible grade of paper for a particular black and white negative, and the correct printing exposure time.
Ultraviolet Filters
Authors: Kasha Michael
Published: January 2009

Filters for selecting narrow bands of ultraviolet frequencies are essential in certain lines of research in optics, spectroscopy, and photochemistry.
Hearing
Authors: Békésy Georg V.
Published: January 2009

The effects of sound can be transmitted to the inner ear in two different ways: by moving the eardrum and its attached ossicles (air conduction), and by vibrating the whole skull, which vibrations are then transferred to the inner ear (bone conduction).
High Altitude Speech
Authors: Rudmose H. W. , Clark K. C. , Carlson F. D. , Eisenstein J. C. , Walker R. A.
Published: January 2009

The whole problem of voice communication in flying, emphasized by military needs at extreme conditions of altitude and noise, has stimulated a concerted effort toward its solution.
Incident and Reflected Power
Authors: Salzberg Bernard
Published: January 2009

Analyses of the propagation of electromagnetic waves through a stratified medium, or along transmission systems such as wave guides and paired conductors, are frequently expressed in terms of incident, reflected, and transmitted power components.
Low temperature physics in Britain
Authors: Shoenberg David
Published: January 2009

When matter is cooled the heat agitation of the particles which make it up becomes less vigorous and this produces many characteristic effects. For instance, a great part of the electrical resistance of a metal is caused by the obstructing influence of the heat motion of the metal atoms on the electrons' motions, and so when the temperature is reduced the resistance falls. Similarly the ability of a magnetic field to line up the magnetic ions of a paramagnetic salt becomes greater as the temperature is lowered and the magnetic susceptibility rises accordingly. In the early years of this century, and particularly after the quantum theory was developed, the atomic theory of matter was applied to many such problems, and on the whole very satisfactory explanations were found for the observed temperature variation of most physical phenomena down to the lowest temperatures then available (in the region of ten to twenty degrees absolute). There were, it is true, many slight discrepancies of detail, but it looked as if these difficulties would disappear if suitable refinements were made to the theory.
Society Activities
Authors: C. E.
Published: January 2009

The Division of Fluid Dynamics of the American Physical Society, established in 1947, has been organized, its by-laws formulated and approved, and its officers duly elected.
Science as reparations
Authors: Edelstein Julius C. C.
Published: January 2009

The wars of the latter half of the nineteenth century served to establish scientists as essential subalterns of the generals and admirals in the successful prosecution of large scale conflict. By the end of World War I, scientists had gained a place in the inner sancta. World War II, of course, saw science enthroned and even exalted, a mystery through whose wonders victory could be achieved.
Shipping radioactive substances
Authors: Evans Robley D.
Published: January 2009

In 1936, the manager of a film processing station in Chicago noticed periodic density variations occuring in rolls of 16-mm film sent in by mail for processing. The possibility that these rolls had been irradiated by unprotected shipments of medical radium or radon in the mails was suspected, and inquiry at the Chicago Post Office proved this to be the case.
Florence in May
Authors: Mayer Joseph E.
Published: January 2009

At the invitation of the Italian Physical Society a symposium on statistical mechanics, arranged by the committee of thermodynamics and statistical mechanics of the International Union of Physics, was held in Florence, Italy from the seventeenth of May to the twentieth of May, inclusive.
Wide Range Monitor
Authors: Reiffel Leonard
Published: January 2009

The gamma radiation associated with many instruments and experiments in nuclear physics can be a grave danger to the operating personnel.
Microscope Objectives
Authors: Grey D. S.
Published: January 2009

A new series of microscope objectives has been studied with which the microscopist may make visual observations and take ultraviolet photographs without altering the focal setting of his instrument.
Institute Doings
Authors: Barton Henry A.
Published: January 2009

Couple the rapid increase in the volume of research published annually since 1945 to the sharp rise in the cost of printing, and it is evident that the economies in paper stock and format recently effected in physics journals merely lessen the gap between expense and income. These measures hold no promise of closing it.
Physics of Powder Metallurgy
Authors: Read Thomas A.
Published: January 2009

We may in time find industry performing a function hitherto associated entirely with scientific societies and universities, if it follows the lead of the Sylvania Electric Products, Inc. which recently sponsored a symposium on the physics of powder metallurgy at Fort Totten in Bayside, Long Island. Walter E. Kingston, manager of Sylvania's Metallurgical Research Laboratories, was the moving spirit of the meeting, which was organized and financially supported by his company independently of any technical society. Kingston assembled a program of twenty-two papers and approximately one hundred and fifty physicists and metallurgists attended.
Physics in Canada: Industry
Authors: Herzberg G. , Howlett L. E.
Published: January 2009

Before the war Canadian industry had very limited interest in physical research.
Acoustics and Chemistry
Authors: Lieberman Leonard
Published: January 2009

The presence of minute amounts of certain salts such as magnesium sulfate in water may produce large increases in the absorption of sound.
---------oscopes
Authors: Hopkins Robert E.
Published: January 2009

An increasing number of scientists and engineers are finding need for instruments to observe events from remote stations.
High Fidelity
Authors: Massa Frank
Published: January 2009

During the Cleveland meeting of the Acoustical Society, the morning of November 6 was devoted to a panel discussion of what constitutes high fidelity reproduction. It was fairly generally agreed that, from an idealistic viewpoint, high fidelity reproduction constitutes bringing to each ear of the listener an exact facsimile of the original sound he would have heard in the auditorium where it was produced.
The Neutrino
Authors: Allen James S.
Published: January 2009

Probably the most obvious reason for introducing the concept of the neutrino is the need for the conservation of momentum and energy in beta decay.
Measuring Polymer Molecules
Authors: Zimm Bruno H.
Published: January 2009

The average molecular size of a common high polymer (the raw material from which plastics and rubber are made) affects most of its properties but the molecules are too large to be measured by x-ray scattering in the ordinary way.
APS at Thanksgiving
Authors: Darrow K. K.
Published: January 2009

The American Physical Society was founded in 1899 in New York City, with a proviso in its first set of by-laws which read as follows: “The meetings shall ordinarily be held in New York.”
Freedom vs security in the modern world
Authors: Cushman Robert E.
Published: January 2009

You physicists have pretty well altered the face of the earth. By the atomic bomb and other achievements in nuclear physics, you have revolutionized the science of warfare, upset the equilibrium between nations, and recast many of mankind's traditional and basic patterns of thought. The physicist of yesterday has plumped himself squarely into some of the toughest issues of statesmanship; the statesman and politician of yesterday is fumbling with the implications of scientific discoveries which he only vaguely understands. While this has been going on, and partly because it has been going on, our relations with the Soviet Union have steadily worsened, until Russia and the Western Democracies now sit glaring malignantly at each other, each wondering what cards the other actually holds, and how and when he proposes to play them.
Optical Coatings
Authors: Scott Noel W.
Published: January 2009

To increase the efficiency of optical components of military equipment, Corps of Engineers technicians have been investigating German developments in optical coatings with the help of German scientists who were familiar with such techniques.
IUPAP in Holland
Authors: Darrow Karl K.
Published: January 2009

The sixth General Assembly of the International Union of Pure and Applied Physics was held on July 8–10, 1948, at Amsterdam, Holland, in the University of Amsterdam. The report which follows is drawn slightly from the writer's memories and notes, mostly however from documents SG 48–6 and SG 48–8 recently received from P. Fleury, Secretary-General of the Union. It is stated in one of these that the complete procès-verbal of the meeting will eventually be published as a brochure, which will no doubt be thick. The writer confirms from his memories that the hospitality of the Dutch to the Assembly, collectively and to its individual members, was magnificent.
Errata
Authors: Gamow George
Published: January 2009

Sir:

Professor R. T. Birge of the University of California has kindly informed me that the value of 2π2me4/h3c given in my article on “Any Physics Tomorrow?” as being equal to 109,677.759 cm−1 is in error, and must be replaced by 109,737.303 cm−1. It will be noticed, however, that this change in the numerical value of the Rydberg constant does not change the main line of arguments presented in the article, and also does not influence the final conclusions.
Creeping Crystals
Authors: Kê T'ing-Sui
Published: January 2009

Ordinary metals consist of an aggregate of individual crystals.
Learn and work
Authors: Owen G. E.
Published: January 2009

A personnel officer considering the placement of students had the following jobs to fill: The Mine Safety Appliance Company of Pittsburgh wanted laboratory assistants; a patent attorney in Harrisburg, Pa. wanted a physics major to work in his office; the Quartz Research Project at Antioch College wanted men to operate high pressure, high temperature autoclaves, and the controlling and recording devices that go with them; the Biology Department at MIT wanted an assistant in a research project in biophysics to develop some techniques for spectroscopy under a microscope.
The Birefringent Filter
Authors: Evans John W.
Published: January 2009

The birefringent filter, invented in 1933 by Bernard Lyot, and independently in 1938 by Yngve Öhman, has been widely used in observing solar limb emission line phenomena which are ordinarily invisible because of the background of atmospheric and instrumental scattered light.
Beryllium poisoning
Authors: Hasterlik Robert J.
Published: January 2009

Beryllium has unique and advantageous properties which make its use imperative in nuclear physics, nuclear reactor technology, metallurgy, and in industry. But there is danger in its use, for beryllium and its compounds have toxic properties and disease-producing potentialities which have not been widely recognized.
Neutrinos
Authors: Sherwin Chalmers W.
Published: January 2009

The baffling thing about the neutrino is our inability to detect it in the free state.
Crystal Elasticity
Authors: Tyndall E. P. T.
Published: January 2009

The elastic properties of such anisotropic bodies as single crystals of metals are expressed in terms of either one or the other of two sets of constants: moduli of compliance or moduli of elasticity.
Cancer biophysics
Authors: Hoffman Joseph G.
Published: January 2009

Cancer brings about the cruelest irony known to man for in cancer the living conscious body can see itself growing wrong. In order to arrive at an understanding of this dread misdirected growth research workers in all the fundamental sciences have been called together to work in our cancer research institutions.
Large Cloud Chamber
Authors: Cowan E. W.
Published: January 2009

One method of increasing the probability of observing interesting cosmic ray events, which are not subject to the control of the observer, is to build a very large cloud chamber. The difficult problem of illuminating a large chamber has been ingeniously solved by Carl D. Anderson and Seth Neddermeyer in the construction of a chamber nearly three feet in diameter.
Hearing Thunder
Authors: Fleagle Robert G.
Published: January 2009

Thunder is seldom heard at distances greater than about twenty-five kilometers from the point of origin.
The origin of cosmic radiation
Authors: Teller Edward
Published: January 2009

In the past years an increasing number of physicists have turned to the investigation of cosmic rays. One reason for this (not often mentioned officially) is that cosmic ray work can be as adventurous as big game hunting. Cosmic radiation is influenced by the magnetic field of the earth and it is different near the equator, in the temperate zones, and near the polar regions. Thus good reasons can be found for a cosmic ray expedition to any part of the globe.
Scintillation Counters
Authors: Jordan W. H.
Published: January 2009

During the past year, the scintillation counter has received widespread acceptance as a fundamental tool of nuclear research. It offers three advantages over previous counters: The light output is proportional to the amount of energy lost by the particle, thereby supplementing the beta proportional counter in the high energy region; it detects gamma rays about a hundred times more efficiently than Geiger counters, without a corresponding increase in cosmic ray background; and the time of passage of the primary particle can be measured to a hundred millionth of a second.
Thin Films
Authors: Billings Bruce H.
Published: January 2009

There are very few people who spend much time on the optical properties of thin films and a large percentage of them attended an international conference on the optical properties of thin films held at Marseille from April 19 to 23.
Double spin-flip approach within equation-of-motion coupled cluster and configuration interaction formalisms: Theory, implementation, and examples
Authors: Casanova David , Slipchenko Lyudmila V. , Krylov Anna I. , Head-Gordon Martin
Published: January 2009

The spin-flip (SF) approach is extended to excitations that flip the spin of two electrons to describe multiconfigurational Ms=0 wave functions via high spin quintet references. Equations and implementation of the double SF (2SF) approach within equation-of-motion coupled-cluster (EOM-CC) and configuration interaction (CI) formalisms are presented. The numerical performance of the resulting EOM-2SF-CC and 2SF-CI models is demonstrated by calculations of symmetric dissociation of O–H bonds in water, electronic states of linear H4, double CC bond-breaking in ethylene, and low-lying states of trimethylenemethyl diradical and 2,4-didehydrometaxylylene tetraradical. The results of active-space variants of 2SF are very close to the more computationally expensive full-space counterparts. An efficient implementation of the active-space approximation of the 2SF-configuration interaction doubles (CID) model termed 2SF-configuration interaction singles (CIS) is also reported. The scaling of 2SF-CIS is only N4, which allows applications to relatively large molecules.
Impression…
Authors: Fermi Laura
Published: January 2009

High peaks are all around; covered with the everlasting snow that defies the heat of the summer. The Mont Blanc, far away to the west, extends in a long jagged line and looks almost slender in the distance. Close by, to the north, stands the Matterhorn, a massive tower, a huge chunk of rock, alluring and forbidding at the same time: a giant that called many adventurers to their death, the most enticing siren of the Alps.
Electronic Pile Simulator
Authors: Bell P. R.
Published: January 2009

The variation of the neutron flux with time in a nuclear chain reactor is determined to a large extent by the delayed emission of a small fraction of the neutrons formed in fission.
High altitude laboratories
Authors: Korff Serge A.
Published: January 2009

Science has always been international, and where it has flourished it has been nurtured by the contributions of men from all nations. High altitude laboratories similarly are especially beneficial if they are organized on an international basis. High altitude laboratories can serve the scientific community in many ways. Properly set up, they can be helpful in reaching the ultimate objectives of science, the ascertaining of new facts and the better understanding of the way nature operates. We shall in this article discuss those high altitude laboratories which are in the free world, and to which visiting scientists are welcomed. Information about the laboratories in the totalitarian nations is not publicly available, and since access to them is impossible, it would serve no useful purpose to describe them.
Polarization
Authors: Nearhoof H. J.
Published: January 2009

The ionosphere is a region of charged particles above the earth which owes its existence to ionization of atmospheric gases by ultraviolet radiation from the sun.
Places of birth and training of physicists
Authors: Murdoch Bernard C. , White Marsh W.
Published: January 2009

There is no obvious formula for predicting the future scientific manpower needs of the United States, but if we depend upon experience gained during the past several years there is every reason to suppose that these needs will become increasingly pronounced for quite some time to come. A number of federal agencies, acting in concert with certain of the professional organizations, are now methodically investigating each of the many factors involved in the present scientific manpower picture in order to see what may be done to insure the country's long-term scientific future. The existing state of international unrest may well extend over a considerable number of years, and it is necessary under the circumstances to know as precisely as possible where we stand with respect to an adequate potential reservoir of scientific and technical manpower. This of course depends largely upon the rate at which American scientists are being trained, as well as upon the quality of the finished product, but any meaningful assessment of the problem must also include a better understanding of some other factors.
Wavelengths of Mercury 198
Authors: Meggers William F. , Kessler Karl G.
Published: January 2009

The international standard of length, a platinum-iridium bar located in a vault at the International Bureau of Weights and Measures near Paris, was measured relative to the wavelength of the red cadmium line by Michelson in 1892, and the value he derived for the wavelength of the red cadmium radiation has been provisionally adopted as the international standard of length.
Science and the ethics of transition
Authors: Hawkins David
Published: January 2009

The lines of communication between science and its social uses have grown shorter and stronger than ever before. An increasing worldliness in science, accelerated and accentuated by the war, has not lapsed in the period following it, and the spirit of this worldliness, moreover, does not seem consistent with the old position of professional unconcern over general social issues.
Radiac Symposium
Authors: McAfee W. S.
Published: January 2009

A decade or so ago the instrumentation needs of radiologists, of x-ray technicians, and of persons working in industrial radiography were met largely by a few manufacturers working in close cooperation with the x-ray division of the National Bureau of Standards. The special problems then encountered in physics laboratories were made relatively minor by taking sensible safety precautions. More recent developments in work with high energy particle accelerators and with nuclear reactors and weapons have extended the physicist's problem with regard to the energy range over which the instrument must give true dosage readings, the radiological intensity ranges which must be covered, and the numbers and types of personnel it may lie necessary to protect—or risk, if such an occasion should arise.
Accelerator Shielding
Authors: Creutz E.
Published: January 2009

Shielding for high energy nuclear particle accelerators should contain elements of rather high atomic weight for inelastic scattering of fast neutrons, as well as an appreciable amount of hydrogen to slow down low energy neutrons.
Sanguine
Authors: Clark John W.
Published: January 2009

Frequently it is of interest in physiological research to study blood flow rate variations as affected by drugs or by external stimuli such as heat.
Meson Decay
Authors: Hincks E. P.
Published: January 2009

The instability of the meson that constitutes a large fraction of the cosmic radiation at sea level has been experimentally established for ten years, and the light charged decay particle that was observed provided a means of directly measuring the mean lifetime—2.2 microseconds—for the process.
Acoustical Anisotropy
Authors: Price W. J.
Published: January 2009

The anisotropy of an acoustc medium gives rise to several interesting phenomena. For any given direction there are in general three possible modes of sound propagation.
“Expectations of a definite form”
Authors: Einstein Albert , Schilpp Paul Arthur
Published: January 2009

By way of introduction I must remark that it was not easy for me to do justice to the task of expressing myself concerning the essays contained in this volume. The reason lies in the fact that the essays refer to entirely too many subjects, which, at the present state of our knowledge, are only loosely connected with each other. I first attempted to discuss the essays individually. However, I abandoned this procedure because nothing even approximately homogeneous resulted, so that the reading of it could hardly have been either useful or enjoyable. I finally decided, therefore, to order these remarks, as far as possible, according to topical considerations.
Microwave studies of magnetic anisotropy of Co nanowire arrays
Authors: Sklyuyev A. , Ciureanu M. , Akyel C. , Ciureanu P. , Yelon A.
Published: January 2009

The effect of magnetocrystalline anisotropy and dipolar interactions in Co nanowire arrays is studied by ferromagnetic resonance (FMR). Microwave measurements performed by the microstripline method are reported for two series of crystalline hcp Co (with the c axis nominally perpendicular [Co(c⊥)] and parallel to the wires [Co(c∥)]) and an amorphous alloy with Co as the main component—Co94Fe5B1. Extrapolation of the high field linear part of the resonance curve (frequency versus dc field) permitted an evaluation of the effective anisotropy fields for saturated samples, as well as of the intrinsic fields HK, showing that the great differences between the three series are due to the magnetocrystalline anisotropy. The HK values for the two series of Co are discussed in terms of a model which accounts for the effect of the distributions of the c axis orientation in systems of uniaxial ferromagnets. The observed dependence of the effective anisotropy fields on the array geometry (wire length and diameter) is interpreted in terms of the interwire dipolar interactions and found to be in agreement with theoretical predictions based on a micromagnetic model. The fact that the resonance frequencies at Hdc=0 are geometry dependent shows that magnetostatic interactions are still significant at remanence. A second series of FMR experiments was performed at constant frequency (38 GHz), with the purpose of obtaining the angle dependence of the resonance field. These experiments provided an alternative method for the evaluation of the effective anisotropy field. The angle dependence of the resonance field for Co(c⊥) fitted the simplest equation for magnets with uniaxial anisotropy, obtained considering only the first order term in the expression of the magnetocrystalline energy as a function of the magnetization orientation. The same is not true for Co(c∥), which required inclusion of a second order term.
AAAS Symposium On Physics
Authors: Bardeen J. , Ney E. P.
Published: January 2009

Physics of the solid state was the subject of one of the four symposia on physics held at the AAAS meeting in New York City last December.
New Electron Microscope
Authors: Page R. S.
Published: January 2009

This paper describes a new microscope designed for universal application in the field of electron microscopy.
Nonastigmatic
Authors: Haber Heinz
Published: January 2009

Cylinders and paraboloids, which, like the sphere, are surfaces of the second degree, were the only aspherical surfaces used for lenses and mirrors until the Schmidt corrector plate, a surface of higher degree, was successfully introduced into optics.
Mathematical Biophysics
Authors: Rapoport A.
Published: January 2009

Torres and Salamanca of the University of Madrid assume that at each opening of the pylorus a fixed fraction of the liquid contents of the stomach empties into the intestine.
At Stanford
Authors: Schiff L. I.
Published: January 2009

The Stanford meeting of the American Physical Society last December 29 and 30 had somewhat greater interest and attendance than was originally expected for a west coast meeting at that time of year. The program consisted of seventy contributed and six invited papers, and the attendance was close to two hundred. Most of those contributing and attending came from the Pacific Coast—California, Oregon, and Washington—although several came from the mountain states and the middle west, and a few from the east. A wide variety of subjects was represented, including reports on infrared spectra, x-rays, nuclear induction, nuclear reactions, particle accelerators, corona studies, artificial mesons, and cosmic radiation.
Physics for adventure
Authors: Houston W. V.
Published: January 2009

“When our good friend Karl Darrow conveyed to me the invitation to speak to you tonight, my first reaction was that nothing could be said in the ten minutes—which I feel is the ultimate limit I can maintain in an after dinner speech—which would signify much of what I believe is the present direction our physics research is taking, or convey very much of what solutions might be sought for some of our dilemmas. And perhaps this is the wrong place to think, at all. It has been my experience on these occasions that the dinner itself, and the desultory talk with one's colleagues, and old friends, constitute the chief enjoyment of the evening. We physicists are like the forthright customer described in a recent New Yorker, who, when asked by the head waitress at Schrafft's, ‘Which way do you prefer to face?’ replied, ‘I prefer to face the table.’
Properties of the mitibule
Authors: Jackson R. W.
Published: January 2009

Evidence in support of this new sub-atomic particle was first found by A. G. Ratz and W. J. Weir in the spring of 1944 at the University of Toronto (Phys. Rev. 66: 366, 1944). Owing to the exigencies of wartime, work on the project was suspended for almost three years. At the present time the mass and charge, if any, of the particle have still not been ascertained with any degree of accuracy, but it is felt that the discovery is likely to prove so important, and so worthy of attention, as to warrant a review of our present knowledge of the particle, in spite of the lack of reliable quantitative measurements. The difficulties in the way of experiments with mitibules will be apparent from the discussion.
Microspectrometer
Authors: Blout E. R.
Published: January 2009

While the infrared spectrometer is now an established tool in chemical and physical research, it has proved difficult to apply such spectroscopic techniques to certain problems because of the relatively small amounts of material, available.
--escence
Authors: Fonda Gorton R.
Published: January 2009

The luminescence of a phosphor is emitted in a spectral band whose identity is clear even in the presence of a complex structure.
Tester for Photographic Lenses
Authors: Back F. G.
Published: January 2009

Testing lenses, particularly photographic lenses, for performance in a simple, fast, and accurate manner is a very difficult problem.
The NRX pile at Chalk River
Authors: Lewis W. B.
Published: January 2009

The NRX pile at Chalk River is distinguished among the known experimental reactors by its high neutron flux, which at its maximum is 6×1012 neutrons/cm2/sec. It ranks among the high power experimental reactors and normally operates above its designed power rating of 10 Megawatts (10,000 kilowatts). The neutron flux is about 10 to 20 times that of a graphite reactor of comparable power and this is due to the smaller physical size of the NRX reactor made possible by the use of heavy water as the moderator to slow down the neutrons. It should be noted that the rating is attained using only natural uranium metal, and enrichment of the fissionable U-235 isotope is not necessary. On the other hand, because of the small size of the reactor and the low total amount of uranium used, enrichment by plutonium or U-235 yields a quick return of available neutrons.
Scientific readiness
Authors: Waterman Alan T.
Published: January 2009

In this issue of Physics Today the Science Advisory Committee of the Office of Defense Mobilization presents an important statement on the role of scientists in mobilization, with special reference to that of scientists in academic institutions.
Physics as a science and an art
Authors: Darrow K. K.
Published: January 2009

The charge of speaking after five such orators as have preceded me is not a light one, and yet is an assignment which should be treated lightly. The hands of the clock are joyously advancing toward the cocktail hour, and they advise me to pervert the famous words beneath a clock in San Francisco and say to myself, “Son, observe the time and fly from wisdom.” The organizers of this meeting actually proposed that I should speak under the title “The Whole of Physics”. Apart of course from my predecessors on this platform, the last man who could probably have done this was Hermann von Helmholtz. It interests me to realize that there are people still living who studied under Helmholtz; they are the last of our contacts with the era of omniscience. The wishes of the organizers will be formally fulfilled if I succeed in saying nothing that is more irrelevant to any one field of physics than to any other. This condition I will attempt to meet.
Office of Technical Services of the Department of Commerce
Authors: Gray Dwight E.
Published: January 2009

Is my invention for disintegrating army tanks at several hundred yards any good? What is the best adhesive to use in laminating leather to glass when the product is to be used in a warm, humid climate? What technical reports are available on the refractive indices of transparent plastics? These particular queries, as far as I know, are imaginary, but they serve to illustrate the kinds of questions to which J. Horace Taxpayer can obtain answers from the Office of Technical Services (OTS) of the U.S. Department of Commerce. Before discussing these services separately, let us look briefly at the genealogy and present organization of the OTS.
“Lab”
Authors: Harnwell G. P.
Published: January 2009

The experimental aspect of science is its most distinguishing characteristic, and laboratory courses are the backbone of a scientific curriculum. There are certain factors, however, which sometimes tend to obscure this fact and to reduce the emphasis on experiment and laboratory work to the inevitable detriment of the quality of scientific instruction. This in turn reduces the extent to which scientific training can make its characteristic contribution toward the solution of any of the broader problems of society.
Physics in France
Authors: Weisskopf Victor F.
Published: January 2009

During a good part of the school year, 1950–51, the author had the opportunity to be in Paris as a guest professor at the Sorbonne University. Chairs for Foreign Professors have been recently established at several French universities with the purpose of inviting scientists from abroad for a limited time in order to promote the exchange of ideas between France and other countries.
A physicist's holiday
Authors: Zucker Alexander
Published: January 2009

On a recent trip to France and Italy the writer has visited many of the physics laboratories there, and talked to a large number of physicists. It is not the purpose of this article to provide the reader with a careful survey of European physics; any number of Europeans are certainly more qualified for that sort of study. Rather, I shall try to present the impressions of a tourist, in this case a physicist.
Notes and Comments
Authors: Mark Carson , Smoluchowski R.
Published: January 2009

To one working in the country's weapons program, and rather used to having such efforts described as being degrading and immoral, it is a little new to have them called passé. For this novelty we have to thank Professor Morse, seasoned evaluator of the country's weapons systems. Under the heading: Must We Always Be Gadgeteers? (Physics Today, Nov. 1950) Professor Morse has given a sort of prospectus for work in operational research. He justly argues a great need for work in that field, and explains how a physicist who does not particularly wish to stay very close to physics could be effective there. Unhappily, in the course of this argument he invents a class of characters: physicists “whose overwhelming desire is to make more gadgets”. He then points at his invention with scorn.
The Brookhaven nuclear reactor
Authors: Borst Lyle B.
Published: January 2009

On August 22, 1950 the Brookhaven reactor became critical. The work of scientists is notable for its lack of drama. It is usually difficult to say when a piece of apparatus starts to work, and it is even more difficult to decide when an experiment is complete. The uranium chain reaction is outstanding, therefore, since the change from an inert subcritical assembly of fissionable material to a supercritical chain reactor is sudden and, to all intents and purposes, discontinuous.