ISSN:0031-9228    

DOI:10.1063/1.2808354

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808356

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

Tokamak research entered a new and important phase last month. Shortly before midnight on 9 December, the 11‐year‐old Tokamak Fusion Test Reactor at the Princeton Plasma Physics Laboratory was fired for the first time with a 50:50 mixture of deuterium and tritium. That's the mixture of hydrogen isotopes envisioned for the first generation of fusion reactors, because DT fusion can be harnessed at much lower temperatures than DD orD3Hefusion, and the cross section for the proton‐proton reaction that powers the Sun is hopelessly small. But until now most tokamak research has been done, for practical reasons, with pure deuterium plasmas.

ISSN:0031-9228    

DOI:10.1063/1.2808357

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

“First light” shone forth this fall from three new synchrotron radiation facilities around the world: the Advanced Light Source, at the Lawrence Berkeley Laboratory in California; Elettra, at the Sincrotrone Trieste in Italy; and the Synchrotron Radiation Research Center, in Hsinshu, Taiwan. With electron energies ranging from 1 to 2 GeV, they are designed to produce high‐brightness beams ranging from the ultraviolet to soft x rays, corresponding to photon energies from 10 eV to several keV. Hard x rays, with energies between 1 and 250 keV, have been produced since the summer of 1992 by the 6‐GeV European Synchrotron Radiation Facility in Grenoble, France. The first of three synchrotron facilities designed to supply hard x rays from undulators, the ESRF is preparing to welcome external users to its site adjacent to the Laue‐Langevin Institute in September 1994.

ISSN:0031-9228    

DOI:10.1063/1.2808358

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

After nearly two decades of research in fiber‐optics technology, what could possibly remain to be discovered? Clearly, the design of optical fibers cannot be improved forever. With current technology, fibers can transmit infrared (1.5‐micron wavelength) light pulses in a single electromagnetic mode with a minimal power loss of 5&percent; per kilometer and without dispersion; such performance is forever fixed by Maxwell's equations and the physics of silica glass waveguides. Yet the field of fiber optics still reserves some surprises. Indeed, the past few years have seen stunning developments in reaction to advances in rare‐earth‐doped fiber amplifiers and nonlinear (or soliton) pulse propagation in fibers.

ISSN:0031-9228    

DOI:10.1063/1.881418

出版商:AIP    

年代:1994

数据来源: AIP

摘要:

My subject is the rationale for public support of science in the post cold‐war era. The first question is, Whose rationale? Congressman George Brown's or Senator Barbara Mikulski's or President Bill Clinton's or Phil Anderson's or Leon Lederman's? Everyone seems to be singing different tunes, and it is hard to hear any harmony in their voices. And yet with the profound changes in the forces that have driven our Federal science and technology policies, it is now more important than ever to find that harmony.

ISSN:0031-9228    

DOI:10.1063/1.881437

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808359

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808360

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808363

出版商:AIP    

年代:1994

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2808368

出版商:AIP    

年代:1994

数据来源: AIP