ISSN:0031-9228    

DOI:10.1063/1.2409975

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1595036

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1595039

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1595040

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1595041

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Silicon is the workhorse of the microelectronics industry. But it has its limitations. Researchers who demand high‐temperature, high‐voltage, and high‐frequency properties in their semiconductors turn instead to a sister material, silicon carbide. Thanks to its larger band gap, SiC remains semiconducting at much higher temperatures, melts at 2800°C, and has a hardness exceeded only by diamond.

ISSN:0031-9228    

DOI:10.1063/1.1595042

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Classical mechanics, like geometry, can yield surprising results in a non‐Euclidean space. One such result, recently discussed in the journalScienceby MIT planetary scientist Jack Wisdom, concerns the motion of a composite object as it undergoes a cyclic series of changes in body shape. Consider, for example, a person making the precise, regular motions of an Olympic swimmer. In empty Euclidean (flat) space, the swimmer's center of mass wouldn't move; water in the pool, of course, provides the external reaction force that propels real swimmers. The curved‐space surprise is that a swimmer executing an appropriate cycle of internal changes can move, even without external forces.

ISSN:0031-9228    

DOI:10.1063/1.1595043

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The security clampdown on the US visa system in the wake of the September 11th terrorist attacks has created problems throughout the scientific and higher‐education communities that are so numerous and complex that a comprehensive solution may be years away. “It's a nightmare,” one high‐ranking State Department official said of the denials, delays, and uncertainties that international students, scientists, and scholars face when trying to enter and work in the US.

ISSN:0031-9228    

DOI:10.1063/1.1595044

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Some 20 years ago, University of Pennsylvania particle physicist Alfred Mann worked hard to create a national underground science laboratory in the US. He came close, but in the end couldn't generate enough interest in the physics community. He was forced to take his neutrino research to the Kamiokande II detector in Japan.

ISSN:0031-9228    

DOI:10.1063/1.1595045

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

How does a minor university land a major observatory? In New Mexico Tech's case, it helped that the university has access to a high, dark site, that the Magdalena Ridge Observatory (MRO) will have national security applications, and that the project has allies in Congress.

ISSN:0031-9228    

DOI:10.1063/1.1595046

出版商:AIP    

年代:1903

数据来源: AIP