Mercury-rare gas visible-UV laser

[No abstract

Comments on “Electric current and electric field induced in a human body when exposed to an incident electric field near the resonant frequency”

[For original paper see R. W. P. King, IEEE Trans. Microwave Theory Tech., vol. 48, no. 9, pp. 147-53 (2000).] The author makes two observations on the original article. The commentator questions whether a seated person is well modeled as a right circular cylinder. The second observation is that King cites only microwave studies on mice to show that electromagnetic radiation causes malignancies. These studies themselves are widely disputed. He then uses simple dimensional scaling to show that 2.45 GHz for a mouse scales to 100 MHz for a man. Such a scaling law may be useful in calculating the resonant frequency for a human subject versus a mouse when treated as antennas, but such scaling is meaningless when the physics of a hypothetical carcinogenic process are unknown

Limiting stable currents in bounded electron and ion streams

The classical static analysis of the infinite planar diode has been extended to include the effects of finite transverse beam size. Simple expressions have been found for the increase in maximum stable current density over that of an infinite stream for finite cylindrical and strip streams flowing between plates of infinite diodes. The results are also given in terms of stream perveance. The effect of a nonuniform distribution of current across the stream is shown to be relatively small. Experimental values of maximum stable current agree with those obtained from the analysis. A further extension of the static analysis has been made to include the effects of additional conducting plane boundaries parallel to the stream motion. For length-to-width ratios L/D less than 0.25 the tube is adequately described by the results for the infinite planar diode and for L/D greater than 4, the infinitely-long drift tube theory suffices. At intermediate values of L/D, the maximum amount of current that can be stably passed through the tube is greater than that predicted by either asymptotic theory

Design for a space qualified laser, phase 1

Design for space qualified helium-neon lase

Flexible MM-wave dielectric waveguides

Flexible dielectric waveguides have been demonstrated at 10 GHz and 94 GHz by filling hollow, low-dielectric-constant polymer tubes with low-loss, high-dielectric-constant powders. Flexible guides with losses as low as 0.12 dB/cm were demonstrated at 94 GHz. These guides also exhibited negligible bending loss for radii of curvature greater than 4 cm

MM-wave dielectric ring resonators

Ring resonators fabricated by filling a rectangular cross-section groove in a polypropylene substrate with a dielectric powder exhibit Q's as high as 2400 at 94 GHz in an 8 cm diameter ring. Directional coupling from adjacent straight dielectric guides was used to form a transmission filter. Previously, we demonstrated a mm-wave dielectric channel waveguide with .09 dB/cm loss (Refs. 1,2) consisting of a rectangular groove in the surface of a plastic substrate filled with a low-loss, high dielectric constant powder. Here we describe mm-wave ring resonators made from powder-core dielectric channel waveguide

A computer operated mass spectrometer system

Digital computer system for processing mass spectrometer output dat

Computer control of mass analyzers

Digital computer control of mass spectrometer

Generation of 1180 Å period gratings with a Xe ion laser

Holographic lithography with the 2315 Å line of a xenon ion laser is used to produce gratings in polymethylmethacrylate. An 1180 Å period grating is made and examined with a scanning electron microscope (SEM). This grating period is appropriate for use as a first-order grating with a GaAs distributed feedback laser