Physical Sciences

Quadrupole Ion Mass Spectrometer for Masses of 2 to 50 Da

H2, He, O2, and Ar can be quantitated at low concentrations in N2.

Posted in: Physical Sciences, Briefs

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Miniature Laser Doppler Velocimeter for Measuring Wall Shear

Interference fringes are configured for sensitivity to a velocity gradient.

Posted in: Physical Sciences, Briefs

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Atom Skimmers and Atom Lasers Utilizing Them

Atom skimmers act as conduits and low-pass velocity filters.

Posted in: Physical Sciences, Briefs

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Gears Based on Carbon Nanotubes

Nanometer size gears could be used in molecular-scale machines.

Posted in: Physical Sciences, Briefs, TSP

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Multifunction Imaging and Spectroscopic Instrument

There would be no repositioning for different observations of the same specimen. A proposed optoelectronic instrument would perform several different spectroscopic and imaging functions that, heretofore, have been performed by separate instruments. The functions would be reflectance, fluorescence, and Raman spectroscopies; variable-color confocal imaging at two different resolutions; and wide-field color imaging.

Posted in: Physical Sciences, Briefs

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Position-Finding Instrument Built Around a Magnetometer

A coarse indication of position is derived from a relatively inexpensive instrument. A coarse-positioning instrument is built around a three-axis magnetometer. The magnetometer is of a type that is made of inexpensive hardware and is suitable for use aboard spacecraft orbiting no more than 1,000 km above the surface of the Earth. A data processor programmed with suitable software and equipped with a central processing unit, random-access memory, programmable read-only memory, and interface circuitry for communication with external equipment are added to the basic magnetometer to convert it into a coarse-positioning instrument. Although the instrument was conceived for use aboard spacecraft, it could be useful for navigation on Earth under some circumstances.

Posted in: Physical Sciences, Briefs

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Improved Measurement of Dispersion in an Optical Fiber

The lower limit of measurability is extended. An improved method of measuring chromatic dispersion in an optical fiber or other device affords a lower (relative to prior such methods) limit of measurable dispersion. This method is a modified version of the amplitude-modulation (AM) method, which is one of the prior methods. In comparison with the other prior methods, the AM method is less complex. However, the AM method is limited to dispersion levels >160 ps/nm and cannot be used to measure the symbol of the dispersion. In contrast,the present modified version of the AM method can be used to measure the symbol of the symbol of the dispersion and affords a measurement range from about 2 ps/nm to several thousand ps/nm with a resolution of 0.27 ps/nm or finer.

Posted in: Physical Sciences, Briefs, TSP

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