The paper describes an interpretation of jet-noise theory and scale-model experiments to highlight physical properties of jet-noise sources at very high speed. The study is prompted by current efforts to suppress the noise of supersonic transport aircraft.

The principal noise sources are shown to be very large-scale wave-like undulations of the jet flow that travel downstream at supersonic speed for a distance of several jet diameters. These motions are relatively well ordered and are probably more akin to recognizable instabilities of a laminar flow than the confused small-scale turbulence. Because of this we postulate a model of the noise generating motions as the instability products of a jet flow of low equivalent Reynolds number. This Reynolds number is based on an eddy viscosity and can be further reduced by artificially increasing the small-scale turbulence level. This step would tend to stabilize the flow and inhibit the formation of large-scale noise producing eddies.

GaAs Schottky barrier diodes remain a workhorse technology for submillimeter-wave applications including radio astronomy, chemical spectroscopy, atmospheric studies, plasma diagnostics and compact range radar. This is because of the inherent speed of these devices and their ability to operate at room temperature. Although planar (flip-chip and beam-lead) diodes are replacing whisker contacted diodes throughout this frequency range, the handling and placement of such small GaAs chips limits performance and greatly increases component costs. Through the use of a novel wafer bonding process we have fabricated and tested submillimeter-wave components where the GaAs diode is integrated on a quartz substrate along with other circuit elements such as filters, probes and bias lines. This not only eliminates the cost of handling microscopically small chips, but also improves circuit performance. This is because the parasitic capacitance is reduced by the elimination of the GaAs substrate and the electrical embedding impedance seen by the diodes is more precisely controlled. Our wafer bonding process has been demonstrated through the fabrication and testing of a fundamental mixer at 585 GHz (Tmix < 1200K) and a 380 GHz subharmonically pumped mixer (Tmix < 1000K). This paper reviews the wafer bonding process and discusses how it can be used to greatly improve the performance and manufacturability of submillimeter-wave components.

Several previous studies have reported that cognitive/behavioural treatments have been relatively ineffective for chronic, drug-resistant depressed patients. In the present report, six chronic, drug-resistant depressed patients were treated with an integrated program consisting of cognitive/behavioural treatment, pharmacotherapy, and short term hospitalization. The obtained improvement rates were substantially better than previous studies. Potential explanations for these findings are discussed.

Arbitral Commission. March 6, 1956.

After the International Court of Justice held the United Kingdom under a duty to submit to arbitral decision the Ambatielos claim, this case was heard by a special arbitral commission which found in favor of the defendant United Kingdom, rejecting the Greek claim. The International Court of Justice ruled that the United Kingdom was under a duty to arbitrate only insofar as the Anglo-Greek Treaty of 1886 gave rise to the claim.