High-Performance Optical Local and Metropolitan Area Networks: Enhancements of FDDI and IEEE 802.6 DQDB.

  • Gitlin R.
  • Karol M.

The Fiber Distributed Data Interface (FDDI) and the IEEE 802. 6 Distributed Queueing Dual Bus (DQDB) are emerging standards for high-speed (45 - 150 Mb/s) local and metropolitan area networks. In this memorandum, we describe several ways to build on these emerging standards to significantly increase the achievable throughput and ...

Detection of Systematic Gravitational Lens Galaxy Image Alignments: Mapping Dark Matter in Galaxy Clusters.

  • Tyson J.
  • Valdes F.
  • Wenk R.

Systematic gravitational lens alignment of 10-60 faint background galaxy images has been detected, centered on foreground galaxy clusters of high velocity dispersion. The background galaxy population is selected by its extreme blue B-R color. At a limiting surface brightness of 29 B magnitude arcsec sup (-2) there are 30 background ...

Zero Temperature Ordering in Two-dimensional Frustrated Quantum Heisenberg Antiferromagnets.

  • Gelfand M.
  • Huse D.
  • Singh R.

We present series expansion investigations of the square lattice spin-1/2 Heisenberg antiferromagnet with nearest neighbor (J sub 1), second neighbor (J sub 2), and third neighbor (J sub 3) exchanges. Expansions for ground state properties around dimerized Hamiltonians in conjunction with finite-size studies and cluster mean-field theories allow us to ...

Gain Dynamics of Erbium-Doped Fiber Amplifiers.

  • Desurvire E.
  • Giles C.
  • Simpson J.

The gain dynamics of erbium-doped fiber amplifiers are studied both experimentally and theoretically. It is shown that the transients associated with gain saturation and gain recovery during multichannel amplification have long characteristic times, i.e., in the 100 microseconds-1 ms range. Such slow gain dynamics effectively prevent saturation-induced crosstalk and intermodulation ...

Czochralski Crystal Growth in the System PtMn sub x Sb2 sub (-x).

  • Barns R.
  • Carlson D.
  • Kammlott G.
  • Laudise R.
  • Sunder W.
  • Witt A.

Crystal growth in the system PtMn sub x Sb sub (2-x) was investigated to explore the possibilities of materials in that system as magnetic semiconductors. Good PtSb sub 2 single crystals were grown by liquid encapsulated Czochralski growth in BN crucibles. The grown crystals were p-type with wig 10 sup ...

Ultrafast Dynamics at Semiconductor and Metal Surfaces.

  • Bokor J.

A variety of important dynamical phenomena at metal and semiconductor surfaces are now being investigated using new ultrafast measurement techniques involving lasers and nonlinear optics. Understanding of the rates and mechanisms for relaxation of optical excitations of the surface itself as well as those of adsorbates on the surface is ...

Conformations and Motions of Polyethylene and Poly(oxyethylene) Chains Confined to Channels.

  • Tonelli A.

Inclusion compounds formed by linear polymers and host clathrates, such as urea and perhydrotriphenylene (PHTP), provide a unique environment for the included polymer chains. We have investigated the conformations and mobilities of isolated polyethylene (PE) and poly(oxyethylene) (POE) chains when confined to the channels of their inclusion compounds. This was ...

Sequential Clustering Reactions of SiD sub 3 sup + and SiH sub 3 sup + with SiH sub 4: Another Case of Arrested Growth of Hydrogenated Silicon Particles.

  • Kolenbrander K.
  • Mandich M.
  • Reents W.

Formation of hydrogenated silicon duct in silane plasmas poses one of the biggest quality control problems in the subminiaturization of silicon devices. Circumstantial evidence suggests that this dust begins as small ions of silane which grow incrementally be reactions with silane. Our current study focusses on the the sequential clustering ...

Radiation damage of titanium diffused lithium niobate devices.

  • Jack C.
  • Kanofsky A.

The damage due to ionizing radiation on titanium diffused lithium niobate waveguide devices is investigated. Several waveguide devices containing straights, bends, and directional couplers are irradiated with both gamma radiation and high energy electrons. Passive optical measurements as well as in-situ measurements are performed on the exposed waveguide devices. It ...

NUCLEAR RELAXATION AND Cu SPIN DYNAMICS IN YBa sub 2 Cu sub 3 O sub (6+x).

  • Bell R.
  • Brennert G.
  • Cava R.
  • Espinosa G.
  • Walstedt R.
  • Warren W.

We report the sup (63) Cu NQR spectrum and nuclear relaxation rates for Cu(2) sites in sup (63) Cu- enriched YBa sub 2 Cu sub 3 O sub (6.64) (T sub c ~ 60K). The spectra reveal the presence of 3 distinct classes of Cu(2) site assumed to reflect local ...

Strain Relaxation Phenomena In Ge sub x Si sub (1-x)/Si Strained Structures.

  • Bean J.
  • Bonar J.
  • Buescher C.
  • Eaglesham D.
  • Hull R.

By in-situ relaxation of metastably strained Ge sub x Si sub (1-x)/Si heterostructures in a transmission electron microscope, we are quantitatively able to study dynamic misfit dislocation phenomena. It is found that dislocation nucleation, propagation and interaction phenomena each play a role in determining the overall rate of strain relaxation ...

Tilting and Vibration of the Skylab Building at the South Pole.

  • Gress J.
  • Stark A.

The angular stability of a large building at the South Pole was measured using a tiltmeter for a period of 11 days. Both the top and bottom floors wobble by approximately 20 seconds of arc on a diurnal cycle, and show long-term drifts of up to 60 seconds of arc. ...

A Field-Induced Charged-Device Model Simulator.

  • Diep T.
  • Jon M.
  • Lin D.
  • Renninger R.
  • Welsher T.

We introduce a new charged-device model simulator that is suitable for rapid, routine testing of semiconductor devices. The Field- Induced Charged Device Model (FCDM) simulator raises the device under test to a high voltage using the field of a non-contacting electrode, which avoids premature device stressing and permits a faster ...

Nondetects, Detection Limits, and the Probability of Detection.

  • Lambert D.
  • Peterson B.
  • Terpenning I.

When chemists cannot quantify the concentration in a field sample, they report nondetect instead of a numerical measurement (a detect). A data analyst might assume that all nondetects are zeros, all nondetects are smaller than the smallest detect, or that all nondetects are below the detection limit. This paper shows ...

Search for Neutrons from Deuterium - Deuterium Nuclear Reactions in Electrochemically Charged Palladium.

  • Broer M.
  • Feldman L.
  • James A.
  • Kraus J.
  • Miller B.
  • Raghavan R.

We report on a search for neutrons from dd fusion in Pd rods loaded electrochemically with deuterium. The rods were held in two electrolytic cells (D sub 2 O (99.5% D)+ 0.1 M LiOD) and placed before a 12.5 dia. x 12.5 cm Nal(T1) spectrometer system. The apparatus was housed ...

Submicron Scaling of AlGaAs/GaAs Self-Aligned Thin Emitter Heterojunction Bipolar Transistors (SATE-HBT) with Current Gain Independent of Emitter Area.

  • Feuer M.
  • Lunardi L.
  • Malik R.
  • Ryan R.
  • Shunk S.

A new, self-aligned process technology for AlGaAs/GaAs Heterojunction Bipolar Transistors (HBT) has been developed, which is based upon ultra-thin (100 - 200 angstrom) AlGaAs emitter layers. The thin AlGaAs emitter is used as a selective etch stop layer for contacting the p sup + base layer and acts as an ...

Resistive Transitions of Ni-doped Ba sub 2 YCu sub 3 O sub 7 in High-Magnetic Fields.

  • Delin K.
  • Foner S.
  • Mcniff E.
  • Orlando T.
  • Vandover R.

Resistive transitions of single crystal Ba sub 2 YCu sub (3-z) Ni sub z O sub 7 were studied in magnetic fields up to 20 tesla. For dopant concentrations of x = 0.01 and x = 0.03, the transition temperature in zero field decreased from the undoped value of 88K ...

Flux Dynamics and Electronics Anisotropy in High Temperature Superconductors.

  • Batlogg B.
  • Palstra T.
  • Schneemeyer L.
  • Waszczak J.

The dissipation below T sub c in external fields up to 12T has been studied in five groups of high temperature cuprates. The dissipation is due to Lorentz-force driven flux motion and is least pronounced in the compound with the smallest electronic anisotropy (Ba sub 2 YCu sub 3 O ...

Measurement of Thermal Expansion Coefficients of W, WSi, WN, and WSiN Thin Film Metallizations.

  • Blech I.
  • Grim K.
  • Lahav A.

Thermal expansion coefficients and biaxial elastic moduli of the sputtered W, WN sub x, WSi sub 0.45, and WSi sub 0.67 N sub 0.10 thin films, used as refractory gate in the self-aligned MESFETs on GaAs, were determined by in-situ stress measurements during heating and cooling of the films on ...

Vortex Depinning in YBa sub 2 Cu sub 3 O sub 7: Resistive Transition Identification of the Crossover from Flux-Creep to Flux-Flow Behavior.

  • Hebard A.
  • Palstra T.

Analysis of resistive transitions of YBa sub 2 Cu sub 3 O sub 7 crystals reveals a scaling behavior which identifies the vortex-depinning critical field H sub cp, hence the crossover in behavior from flux creep to flux flow. The inferred H sub cp for YBa sub 2 Cu sub ...