ISSN:0031-9228    

DOI:10.1063/1.2815195

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2815196

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2815197

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

It is a canon of cosmology that on a large scale the universe is homogeneous and isotropic. If you peer out far enough, it should look about the same in all directions. During the last several months, astrophysicists have been wrestling with the serious implications of observations indicating that locally the expansion of the universe may not be uniform in every direction, even when we look out as far as a hundred million parsecs. Last January at a NATO workshop in Hawaii, an international group of seven astrophysicists claimed to have found observational evidence for a bulk streaming motion of the galaxies throughout our extended neighborhood—out to much larger distances than expected.

ISSN:0031-9228    

DOI:10.1063/1.2815198

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The large Tokamak Fusion Test Reactor at the Princeton Plasma Physics Laboratory has entered a new regime of “enhanced confinement” operation. The first spectacular consequence of this new regime is the attainment of a record ion temperature of 20 keV—more than 200 million kelvin. For the first time, a tokamak is creating plasmas with ion temperatures hot enough for ignition and fusion‐reactor operation.

ISSN:0031-9228    

DOI:10.1063/1.2815199

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

For 30 years after the second world war, the United States dominated experimental particle physics. This dominance was particularly pronounced during the 1950s, when the leading US machines dwarfed those in Western Europe, while ostensibly equivalent facilities in the Soviet Union posed little threat. The 1960s witnessed the beginning of a European challenge from the new Proton Synchrotron at the joint European laboratory CERN near Geneva and from various smaller machines in national laboratories such as DESY at Hamburg. Yet despite a broad similarity in the research facilities available on either side of the Atlantic, the major discoveries of the 1960s—the&OHgr;−,the two types of neutrino, CP violation and deep inelastic electron scattering—all came from the US.

ISSN:0031-9228    

DOI:10.1063/1.881042

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Only someone with a short‐range view could fail to be aware of the great importance of long‐range interactions. Indeed, from the late 18th century, when Coulomb discovered that the electrostatic interaction has the same1/r2force law that Newton had found for the gravitational interaction, until perhaps the 1930s, when the strong and weak interactions began to be understood, long‐range interactions largelywerethe subject of physics. By long‐range interactions I mean not only those for which the potential behaves as1/rfor allrbut those whose potentials behave asymptotically as some power of1/r.These originate in1/rpotentials and include, for example, the van der Waals1/r6interaction (as calculated nonrelativistically) between two spherically symmetric atoms at a large separationr, and multipole interactions between charge distributions. Long‐range potentials therefore not only play a vital role in astrophysics via Newton's law of gravitation and a significant role in nuclear physics via Coulomb's law, but determine almost all of atomic, molecular and condensed‐matter physics.

ISSN:0031-9228    

DOI:10.1063/1.881043

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Our traditional approaches to science and mathematics education are based largely on intuitive notions and are, in some ways, rather unscientific. Whereas we usually tackle problems in science and engineering through the systematic use of fundamental principles, we often approach problems in science teaching by the seat of our pants, without deeper analysis. While we make great efforts in physics to understand the mechanisms that underlie observed phenomena, we are often content to consider scientists and students as “black boxes” whose internal intellectual functioning can be left largely unexamined in spite of its importance for teaching.

ISSN:0031-9228    

DOI:10.1063/1.881044

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2833549

出版商:AIP    

年代:1986

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2815201

出版商:AIP    

年代:1986

数据来源: AIP