The distribution of magnetic moment magnitudes in an AlMnSi quasicrystal.

  • Chen H.
  • Eibschutz M.
  • Lines M.
  • Waszczak J.

Magnetic susceptibility measurements on quasicrystalline i- Al sub (74) Mn sub (20-x) V sub x Si sub 6 establish that vanadium substitutes for manganese only at magnetic sites, and in a manner which preferentially occupies first those manganese sites with the largest local magnetic moments. Since vanadium possesses no local ...

Nonequilibrium Phonon Dynamics in a Semiconductor Quantum Well.

  • Cai W.
  • Lax M.
  • Marchetti M.

The dynamics of nonequilibrium phonons in heterolayers, where the carriers are quasi-two-dimensional (2D) while the equilibrium lattice excitations are those of the bulk (3D), require a new theoretical approach. We have derived a kinetic equation for the phonon one-body density matrix, and then transform it to a tractable set of ...

AUTOTEST-2: An expert system for special services.

  • Ackroff J.
  • Surko P.
  • Wright J.

AutoTest-2 is an AT&T expert system to test telephone company special services circuits. It is a forward chaining system of about 600 rules and a few dozen procedures and functions, written in OPS/83 and running as part of an existing operations support system under the UNIX(TM) operating system on VAX/780's.

Zero Field Nuclear Magnetic Resonance in High Field: The Untruncation of Dipole-Dipole Couplings.

  • Tycko R.

High field NMR spectra of solids that are not single crystals typically exhibit broad powder pattern lineshapes that arise from the orientation dependence of nuclear spin couplings. In this paper, we describe the first experimental demonstration that the orientation dependence of nuclear magnetic dipole- dipole couplings can be removed in ...

Multimode interference generation in the horn reflector antenna system during multipath fading.

  • Kenny J.

This memorandum estimates the amount of interference generated in the horn-reflector antenna system due to higher order mode echoes during multipath fading. The model is based on a two- ray description of the multipath fade, the higher-order mode directivity patterns of the horn-reflector antenna and an estimate of the backward ...

Femtosecond Continuum Generation in Fibers near 1.6microns.

  • Bar-Joseph I.
  • Chemla D.
  • Gordon J.
  • Islam M.
  • Sucha G.

We generate in a fiber continuum with ~ 100fsec duration between 1.55 and 1.8microns. The continuum originates from multi-soliton collisions because of modulation instability and self-frequency shift effects.

Laser-induced decomposition of triethylgallium and trimethylgallium adsorbed on GaAs(100).

  • Donnelly V.
  • Mccaulley J.
  • Mccrary V.

We report X-ray photoelectron spectroscopy (XPS) studies of excimer laser stimulated decomposition of triethylgallium (TEGa) and trimethylgallium (TMGa) adsorbed on GaAs(100) surfaces in ultrahigh vacuum. TMGa and TEGa dissociatively chemisorb on GaAs at room temperature, whereupon irradiation by a pulsed ArF excimer laser at 193 nm leads to further dissociation ...

Penetration Depths of High-T sub c Films Measured by 2-Coil Mutual Inductances.

  • Fiory A.
  • Hebard A.
  • Howard R.
  • Mankiewich P.

A fundamental parameter of sample quality in epitaxial films of high T sub c oxides is the effective penetration depth lambda sub || of the superconducting sheet. We describe our contactless audio-frequency method, an arrangement in which a YBa sub 2 Cu sub 3 O sub 7 film on SrTiO ...

N+/P+ poly gate CMOS process using source/drain implants for poly doping.

  • Chen M.
  • Doklan R.
  • Lin W.
  • Lu C.

N+/P+ poly gate CMOS devices were fabricated using source-drain implants for polysilicon doping and a process modified from the 0.9micron CMOS processing technology. CMOS devices so fabricated show comparable characteristics to devices fabricated by conventional 0.9micron technology. No short channel effects were observed at L sub eff of 0.6micron and ...

Nature of Simple Photodissociation Reactions in Liquids on Ultrafast Timescales.

  • Brown J.
  • Harris A.
  • Harris C.

This review article, to appear in Annual Reviews of Physical Chemistry (1988), describes recent advances in understanding the ultrafast dynamics of diatomic photodissociation reactions in liquids. Such reactions form a basis for conclusions about reactant-solvent energy exchange, and for the nature of solvent caging effects in bimolecular reactions. Emphasis is ...

Computer Generated Gratings with Multiple Phase Levels.

  • Jahns J.
  • Walker S.

Phase gratings with more than two quantization levels have recently been of interest for making unusual optical components like lenslet arrays or beamsplitters with multiple outputs. Using more than two phase levels can be beneficial, for example, to increase the efficiency of computer generated diffraction gratings used in array generation. ...

Semiconductor Optical Amplifiers.

  • Olsson N.

Recent advances have brought semiconductor amplifiers to the stage where lightwave system employing amplifiers in some aspects clearly out-performs traditional systems. For example, the longest non-regenerated fiber transmission experiments use optical repeaters, and at high data-rates (4 GBit/s), receivers with optical pre-amplifiers are substantially more sensitive than their coherent and ...

Atomic Reordering and Lattice Mismatch - (Meta) Stability in Heteroepitaxial Layers.

  • Chang T.
  • Chelluri B.
  • Pangilinan G.
  • Sooryakumar R.

We report the first evidence of lattice mismatch stain induced atomic reordering within a single crystalline epilayer in a film-substrate structure. The Raman activity of Zn sub 3 As sub 2 layers, grown by molecular beam epitaxy on InP and GaAs, confirms an ordered migration of specific Zn atoms over ...

Chemical Etching of (001) InP by HBr-H sub 2 O sub 2 -H sub 2 O-HCI Solution.

  • Huo D.
  • Wilt D.
  • Wynn J.
  • Yan M.

We developed a new etchant system based on HBr, H sub 2 O sub 2, HCI and H sub 2 O for (001) InP wafers. We discovered that HCI and HBr have different reactivities with different {111} planes of InP. Etching behavior of our new etchant system was shown to ...

Extreme Nonequilibrium Electron Transport in Heterojunction Bipolar Transistors.

  • Berthold K.
  • Levi A.
  • Malik R.
  • Walker J.

We use hot electron spectroscopy to demonstrate the existence of extreme nonequilibrium electron transport in the base of n-p-n heterojunction bipolar transistors. In the device, electrons are tunnel injected into a thin (~300angstroms wide), degenerately doped, p-type GaAs base.

Flux growth of superconducting single crystals in the Bi-Sr- Ca-Cu-O system.

  • Batlogg B.
  • Fleming R.
  • Glarum S.
  • Marshall J.
  • Rupp L.
  • Schneemeyer L.
  • Siegrist T.
  • Sunshine S.
  • Van Dover R.
  • Waszczak J.

We report the growth of single crystals of high T sub c superconductors in the Bi-Sr-Ca-Cu-O system from alkali halide fluxes. Crystals grow as very thin black platelets with cm sup 2 surface areas and have nominal composition Bi sub (2.2) Sr sub 2 Ca sub (0.8) Cu sub 2 ...

Improved press forging of Ba sub 2 YCu sub 3 O sub 7 superconductor.

  • Grader G.
  • O'Bryan H.
  • Rhodes W.

An improved press forging technique has yielded ceramic Ba sub 2 YCu sub 3 O sub x with a very high degree of orientation and mechanical integrity. The as forged samples are dense and tetragonal and have an oxygen content of ~6.3. By a partial oxidation of the samples, a ...

Pseudoharmonic Oscillators and Inadequacy of Semiclassical Quantization.

  • Stillinger D.
  • Stillinger F.

A fundamental property of harmonic oscillators is that their classical motions have energy-independent periods. This property is not confined to harmonic oscillators, but includes a broad family of anharmonic cases as well. The Einstein-Brillouin- Keller prescription for semiclassical quantization leads to the familiar harmonic oscillator spectrum for all of these ...

Spectral function of holes in a quantum antiferromagnet.

  • Ruckenstein A.
  • Schmitt-Rink S.
  • Varma C.

Using an effective Hamiltonian which takes into account the constraints on the motion of a hole in a quantum antiferromagnet (QAFM), the spectral function of the hole is calculated. For small exchange, the majority of the spectral weight, except near the QAFM zone boundary, is found to be in the ...

Comparison of the Contribution of Diffuse and Dense Clouds to the Large-Scale CO Emission of the Galaxy.

  • Knapp G.
  • Polk K.
  • Stark A.
  • Wilson R.

Diffuse molecular clouds make a significant contribution to the CO emissivity of the Galaxy, but have little mass.