ISSN:0031-9228    

DOI:10.1063/1.3022961

出版商:AIP    

年代:1971

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3022917

出版商:AIP    

年代:1971

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3022919

出版商:AIP    

年代:1971

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3022921

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

One of the first experiments to be done at the new CERN Intersecting Storage Rings has verified certain scaling laws developed by Richard Feynman (Cal Tech) and by C. N. Yang (State University of New York at Stony Brook) and his collaborators. The experiment was just reported by Lazarus G. Ratner (Argonne), Richard J. Ellis and Gianni Vannini (University of Bologna), Bryce A. Babcock, Alan D. Krisch and Jabus B. Roberts (University of Michigan) in the 5 July issue ofPhysical Review Letters.

ISSN:0031-9228    

DOI:10.1063/1.3022923

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A new way of transferring charge in an electrostatic accelerator has been developed by the National Electrostatics Corp in Middleton, Wisconsin. Instead of using the traditional Van de Graaff belt‐charging system, the “Pelletron” system consists of an endless chain of metal pellets joined by solid links of insulating material such as molded nylon; the pellets carry charge to the high‐voltage terminal. Other charge‐transfer devices used in electrostatic machines of the past include the rotating glass disc of the Wimshurst machine and the rotating plastic cylinder of the SAMES machines. Pelletron machines offer improved dependability and voltage stability over belt‐charged electrostatic machines, according to Raymond G. Herb, president of the corporation.

ISSN:0031-9228    

DOI:10.1063/1.3022924

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Eskimo roller.Actually James C. Sindelar is not an eskimo but an associate professor of electrical engineering at New Hampshire Technical Institute. He wrote the winning entry in the competition, sponsored by the Old Town Canoe Company, advertised in the January issue ofphysics today; our photograph shows him in the slalom kayak that was awarded as the competition prize.

ISSN:0031-9228    

DOI:10.1063/1.3022926

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Ever since the initial successes of the theory of relativity, physicists and philosophers of science have written a great deal about a paradox that seems to arise when theory tries to answer the question: If two identical stationary clocks in the same inertial frame of reference are synchronized, and if one of them is accelerated away into different inertial frames and then returned to the original inertial frame, would the time readings of the clocks still be synchronized at this later rendezvous?

ISSN:0031-9228    

DOI:10.1063/1.3022927

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Suppose you have been asked to measure the temperature of an object known to be at around 1000°C. Being a knowledgeable physicist, you know that the most accurate procedure is to obtain the best thermocouple you can and use it carefully, in accordance with the manufacturer's instructions. The calibration table that comes with the instrument charts emf values to the nearest microvolt, corresponding to about 0.1°C, and with practice you find you can get reproducible readings within this interval. Does this mean that you are measuring temperature to±0.1°Caccuracy?

ISSN:0031-9228    

DOI:10.1063/1.3022928

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

The Gum Nebula is seen on photographs of the southern skies as an extensive region of ionized hydrogen that surrounds the well known Vela X supernova remnant. One of the largest objects in our galaxy, the Nebula was first recognized as a single emission complex by Colin S. Gum during the 1950's. Until recently, astronomers assumed that it was a “Stro¨mgren sphere,” excited by ultraviolet light from the hot stars gamma Velorum and zeta Puppis within it. This excitation process accounts for the Orion Nebula and other H‐II regions. The synchrotron and thermal bremsstrahlung mechanisms account for the radiation from supernova remnants, such as the Crab Nebula and Vela X; these objects consist of rapidly expanding matter ejected by the supernova explosions.

ISSN:0031-9228    

DOI:10.1063/1.3022929

出版商:AIP    

年代:1971

数据来源: AIP