摘要:

One of the strangest anomalies thus far exhibited by matter has been the special thermal wave property of liquid helium II, known assecond sound. Characteristic of no other substance than helium II—that weird form adopted by liquid helium below the &lgr;‐temperature of 2.19°K—second sound is essentially an undamped thermal wave propagation. Such thermal waves display all the usual properties of wave phenomena, including resonance and reflection characteristics. This property of heat flow conforming to a wave equation, rather than to the classical diffusive heat flow equation, results in such seemingly paradoxical situations as heat flowing uphill against thermal gradients. Anomalous even in name, second sound never activates microphones and is generated by heat impulses rather than by mechanical impulses. Finally, its behaviour provides perhaps the most effective means for investigating and understanding the true nature of this so‐calledquantum liquid, helium II, and the associated quantum hydrodynamics.

ISSN:0031-9228    

DOI:10.1063/1.3061038

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The summit of a dormant volcano nearly three miles high and located in the wilds of central Alaska—this is the unlikely site of a cosmic‐ray laboratory that was put into operation during the past summer. Established by an expedition under the joint sponsorship of New York University and the University of Alaska, and with the substantial assistance of the Army, Navy, and Air Force, the Mount Wrangell Observatory can now be added to the roster of the world's high altitude stations.

ISSN:0031-9228    

DOI:10.1063/1.3061010

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3061012

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3061015

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3061020

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

On August 21st, one hundred and forty‐four stormy days after the forced resignation of Allen V. Astin as director of the National Bureau of Standards (seePhysics Today,VI, 5,20, May 1953), Secretary of Commerce Sinclair Weeks issued the following press release:“I have asked Dr. Allen V. Astin to continue as Director of the National Bureau of Standards and he has agreed to do so. I am taking this action because I am convinced that it is in the best interests of the Bureau and the public.

ISSN:0031-9228    

DOI:10.1063/1.3061023

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

The designations by the Office of Naval Research of its summer arctic expedition as “Project Mushrat” and its equatorial expedition later on, as “Project Churchy” evolved, one is told, from the use of balloon‐launched Deacon rockets on the former expedition and from the prevalence of turtles on the Galapagos Islands, the site of the latter work. The purpose of both projects was to make comprehensive series of high altitude observations of the primary cosmic radiation, and the pressure, temperature and density of the atmosphere near the geomagnetic north pole and the equator.

ISSN:0031-9228    

DOI:10.1063/1.3061024

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Multiple meson productionin neutron‐proton collisions has been observed by a group working with the Cosmotron at Brookhaven National Laboratory.

ISSN:0031-9228    

DOI:10.1063/1.3061026

出版商:AIP    

年代:1953

数据来源: AIP

摘要:

Ludwig Prandtl,internationally known expert on aerodynamics, died in Germany on August 19th. He was seventy‐eight. During his life‐time, Professor Prandtl had been director of the Kaiser Wilhelm Institute for Fluid Motion Research and of the Institute for Technical Physics at the University of Goettingen. He was an honorary member of the American Academy of Arts and Sciences and the recipient, in 1930, of the Daniel Guggenheim Gold Medal for “conspicuous merit” in aerodynamics.

ISSN:0031-9228    

DOI:10.1063/1.3061031

出版商:AIP    

年代:1953

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3061032

出版商:AIP    

年代:1953

数据来源: AIP