ISSN:0031-9228    

DOI:10.1063/1.2915929

出版商:AIP    

年代:1984

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2915892

出版商:AIP    

年代:1984

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2915905

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

Construction has begun at DESY on an electron–proton collider, the first of its kind in the world. This Hadron Electron Ring Accelerator, or HERA, will collide 820‐GeV protons with 30‐GeV electrons, providing 314 GeV in the center of mass. The proton storage ring uses 4.53‐T superconducting magnets. The electron storage ring, on the other hand, uses conventional technology. But the ring will produce longitudinally polarized electrons, a capability never achieved in a storage ring before. Because of this capability and its high center‐of‐mass energy, when HERA starts running experiments in 1990, it should shed new light on the weak interaction by charged and neutral currents with quarks

ISSN:0031-9228    

DOI:10.1063/1.2915908

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

From the Crystal Ball detector at theDORISelectron–positron collider in Hamburg comes strong evidence of an 8.3‐GeV particle for which there appears to be no prosaic explanation. “If it's real, it has to be very important,” says Gordon Kane (University of Michigan), expressing the widespread excitement that this new state has generated among high‐energy theorists.

ISSN:0031-9228    

DOI:10.1063/1.2915909

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

A group of 150 scientists led by Maury Tigner of Cornell submitted a report to DOE in May containing three reference designs for the Superconducting Super Collider. In June the Universities Research Association, which is to administer the R & D phase of the SSC project, designated Tigner as director of the SSC design and R&D program. The Department of Energy, in its FY 1985 budget request, had asked for $20 million for R&D on the collider. However, it was not until mid‐August that it decided to release the $20 million at the start of FY 1985, on 1 October.

ISSN:0031-9228    

DOI:10.1063/1.2915910

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

In the past few years, the focus of research in condensed‐matter physics has shifted to exotic materials, novel structural arrangements, surfaces, interfaces and imperfect systems. Advances leading to the fabrication of metal oxide–semiconductor devices and superlattice structures, for example, have made possible the study of quantum‐well structures and the discovery of the quantum Hall effect. After a decade of progress with this technology, combined with advances in computer‐controlled processing, we can now tailor composition and impurity profiles at an atomic level, monitor the effects that a fraction of a monolayer of atoms has on a surface and control the deposition of atoms layer by layer, capabilities that have already led to the discovery of new physics, such as the fractional quantum Hall effect. (SeePHYSICS TODAY, July 1983, page 19.) Venkatesh Narayanamurti, in his article on page 24, captures the excitement of the strong interplay between basic physics and technology in condensed matter physics.

ISSN:0031-9228    

DOI:10.1063/1.2915911

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

The great advances in solid‐state electronics can be traced to a unique combination of basic conceptual advances, the perfection of new materials and the development of new device principles. Ever since the invention of the transistor at Bell Laboratories almost forty years ago, we have witnessed a spectacular growth in silicon technology, leading to increasingly higher densities of devices and more complex functions. Almost as revolutionary as the invention of the transistor in 1947 was the invention of the laser a decade later. Thus, nearly concurrent with the electronics revolution, we have seen another technological revolution, the so‐called photonics revolution: using beams of laser light for information transmission. The lasers that provide light for today's lightwave communication systems are made not from silicon but from compound semiconductors. These are generally compounds of elements from group III of the periodic table, such as Ga, Al and In, along with elements from group V, most notably As, P and Sb.

ISSN:0031-9228    

DOI:10.1063/1.2915912

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

After rapid growth over the past 15 years, research on noncrystalline semiconductors is now one of the most active and exciting areas in condensed‐matter physics. Technological interest has always been an important stimulant for fundamental materials research, and work on noncrystalline semiconductors is no exception. The field is active because the unique properties of these new semiconductors, together with techniques for spreading thin films over large areas, open many new possibilities for applications. Among the noncrystalline semiconductor devices at one or another stage of research or development are optical memory disks with extremely high information density, large‐area electronic circuits on thin flexible substrates, faster and more durable photoreceptor drums for xerographic copying machines, x‐ray lenses, holograms and inexpensive photovoltaic cells, just to mention a few

ISSN:0031-9228    

DOI:10.1063/1.2915913

出版商:AIP    

年代:1984

数据来源: AIP

摘要:

In elementary science courses, we learn that matter can exist in the gaseous, liquid or solid states. In more advanced courses, we divide the solid state into regular periodic solids, possibly with defects, and amorphous solids such as glasses. Although these classifications are useful, they are incomplete and do not reflect the full variety of states of natural and synthetic materials.

ISSN:0031-9228    

DOI:10.1063/1.2915914

出版商:AIP    

年代:1984

数据来源: AIP