ISSN:0031-9228    

DOI:10.1063/1.2808894

出版商:AIP    

年代:1993

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808895

出版商:AIP    

年代:1993

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808896

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Theorists trying to explain the mechanism for superconductivity in the copper oxide materials may not agree on much, but they all do believe it involves the coupling of electrons of opposite spin. Paths quickly diverge when it comes to the angular momentum of the pair. Is it a BCS‐like swave (withl = 0)? A d‐wave? Or something else? The answer is linked to the mechanism that couples the electrons. Although early experiments seemed consistent with an swave pairing, recent measurements suggest that the pairing state is at least not isotropic. If the experiments can further delineate the symmetry of the pairing state, they might help narrow the field of contending theories.

ISSN:0031-9228    

DOI:10.1063/1.2808897

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

Scientists are always pushing to new frontiers, which often involve questions about phenomena that occur on very large or very small scales. Astronomers search for new stars millions of light‐years away in a quest to learn how these stars and the universe were born, and particle physicists look at elementary particles of size less than10−17 cmin an effort to understand fundamental interactions. Meanwhile, however, many biologists, chemists and condensed matter physicists are trying to understand natural phenomena that we encounter every day and that occur on some intermediate scale. Questions at this scale are posed in terms of interactions between electrons or atoms and chemical bonds or in terms of atomic theories. The motivation is not only scientific curiosity but also a desire to discover new effects, create new molecules and materials, and develop new technologies that may benefit society. Although a single interaction, electromagnetism, determines the chemical and physical properties of molecules and materials, nature manifests electromagnetic forces in so many forms and in so many phenomena that many of them are by no means understood. One of the powerful tools at our disposal for studies on the microscopic scale or atomic scale is the atomic‐resolution microscope.

ISSN:0031-9228    

DOI:10.1063/1.881389

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

A 150‐meter‐long outdoor beam line wanders through eucalyptus trees down the 45‐meter slope connecting the SuperHILACand the Bevatron at the Lawrence Berkeley Laboratory. The SuperHILACis a linear accelerator designed to accelerate heavy nuclei at high intensities to energies of up to 8 MeV/nucleon for the purpose of studying heavy and superheavy elements. The Bevatron is a weak focusing synchrotron born in 1954 with the mission of discovering the antiproton and exploring the riddle of the hadrons using beams of 6.2‐GeV protons. In 1974 these two machines were coupled to create the Bevalac, and with it a new field of research: relativistic heavy‐ion reactions.

ISSN:0031-9228    

DOI:10.1063/1.881390

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

The arrival of a new Administration in Washington raises once more the question of setting priorities for science and technology. However, this may not be quite the right question. Setting priorities can be difficult without goals. If we don't have goals, if we don't know where we are going, it's hard to have a sensible discussion about the best way of getting there.

ISSN:0031-9228    

DOI:10.1063/1.881391

出版商:AIP    

年代:1993

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808898

出版商:AIP    

年代:1993

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808899

出版商:AIP    

年代:1993

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808900

出版商:AIP    

年代:1993

数据来源: AIP