摘要:

The Boltzmann equation is solved analytically for a physically reasonable model of dilute neutral gas transport through a prism containing randomly located hard sphere scattering centers. The role of boundary and bulk scattering in establishing local equilibrium is clearly illustrated. Asymptotically exact expressions are given for the particle density, pressure, and temperature distributions in the limits of large and small mean free path. The particle flux and the heat flux are calculated exactly for all values of the mean free path.

ISSN:0002-9505    

DOI:10.1119/1.10197

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

A brief summary of the mathematical properties of functional differential equations is followed by two examples, taken from classical dynamics, which clarify the meaning of the peculiar initial conditions required for their solutions. The extensions of these solutions forwards and backwards in time are also discussed, both in the theory and in the examples.

ISSN:0002-9505    

DOI:10.1119/1.10442

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

As part of a senior level course in nuclear laboratory techniques, the lifetime of the 482.0‐keV level of181Ta has been measured by the differential coincidence method in order to illustrate some of the principles involved in a fast timing experiment. An inexpensive source for the experiment was prepared by irradiating natural hafnium metal in a neutron howitzer for a period exceeding 90 days. With simple detectors and electronics, a time resolution width of better than 3.5 nsec was obtained. Within a few lab periods the students were able to align the system and obtain a delayed coincidence time spectrum from which they were able to determine the lifetime of the 482.0‐keV level to within ±15% of the accepted value, 10.8 nsec.

ISSN:0002-9505    

DOI:10.1119/1.10443

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

The treatment of electricity in each of the three most widely used National Science Foundation sponsored elementary science programs (SAPA, SCIS, and ESS) is examined. A first impression tends to leave one with the feeling that the approaches parallel each other; however, each program is quite different in its orientation, and the treatment of subject matter is quite different. The author has selected the concept of electricity to illustrate these different approaches in a comparative setting.

ISSN:0002-9505    

DOI:10.1119/1.10444

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

摘要:

Reflection of coherent light from a cylindrical glass tubing gives many interference fringes which extend around the tube for more than 180° from the incident beam direction. These fringes have a spacing which varies with angle. The cause of this interference pattern is the superposition of the reflections from the outer and inner surfaces of the cylinder. Excellent agreement is obtained between experimental and theoretical results of the magnitude of the fringe separation as a function of angular direction.

ISSN:0002-9505    

DOI:10.1119/1.10445

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10446

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10447

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10448

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10449

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.10450

出版商:American Association of Physics Teachers    

年代:1976

数据来源: AIP