2,223 research outputs found

    An experimental investigation of Harrington's theory of intensity measurements Status report, 1 Jan. 1967 - 1 Jan. 1969

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    Experimental verification that spectrometer signal is linear function of absorber partial pressure for pure gase

    Measurement of tropospheric carbonyl sulfide by microwave spectrometry

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    Microwave rotational spectrometry is used to measure tropospheric carbonyl sulfide. The instrument and techniques for using it are described

    Laboratory Spectroscopy of Astrophysically-Relevant Materials: Developing Dust as a Diagnostic

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    Over forty years ago, observations in the new field of infrared astronomy showed a broad spectral feature at 10 microns; the feature was quickly associated with the presence of silicate-rich dust. Since that time, improvements in infrared astronomy have led to the discovery of a plethora of additional spectral features attributable to dust. By combining these observations with spectroscopic data acquired in the laboratory, astronomers have a diagnostic tool that can be used to explore underlying astronomical phenomena. As the laboratory data improves, so does our ability to interpret the astronomical observations. Here, we discuss some recent progress in laboratory spectroscopy and attempt to identify future research directions

    A Cryogenic Infrared Calibration Target

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    A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R≤0.003R \le 0.003, from 800−4,800 cm−1800-4,800\,{\rm cm}^{-1} (12−2 μ(12-2\,\mum). Upon expanding the spectral range under consideration to 400−10,000 cm−1400-10,000\,{\rm cm}^{-1} (25−1 μ(25-1\,\mum) the observed performance gracefully degrades to R≤0.02R \le 0.02 at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to ∼4 \sim4\,K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials -- Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder -- are characterized and presented

    Evaluating the alternatives of disposal or utilization of the government property at Fort Missoula upon closure.

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    Measurement of the widths of microwave spectral lines /

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    Cyclical Tests of Selected Space Shuttle TPS Metallic Materials in a Plasma Arc Tunnel. Volume 2: Appendices - Data Tabulation

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    Calibration data are presented for heat flux and pressure profiles, model temperature histories, and model weight and thickness changes

    Cyclical tests of selected space shuttle TPS metallic materials in a plasma arc tunnel Volume 1: Description of tests and program summary

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    Work, concerned with cyclical thermal evaluation of selected space shuttle thermal protection system (TPS) metallic materials in a hypervelocity oxidizing atmosphere that approximated an actual entry environment, is presented. A total of 325 sample test hours were conducted on 21 super-alloy metallic samples at temperatures from 1800 to 2200 F (1256 to 1478 K) without any failures. The 4 x 4 in. (10.2 x 10.2 cm) samples were fabricated from five nickel base alloys and one cobalt base alloy. Eighteen of the samples were cycled 100 times each and the other three samples 50 times each in a test stream emanating from an 8 in. (20.3 cm) diam exit, Mach 4.6, conical nozzle. The test cycle consisted of a 10 min heat pulse to a controlled temperature followed by a 10 min cooldown period. The TD-NiCrAl and TD-NiAlY materials showed the least change in weight, thickness, and physical appearance even though they were subjected to the highest temperature environment

    Engineering Functional Quantum Algorithms

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    Suppose that a quantum circuit with K elementary gates is known for a unitary matrix U, and assume that U^m is a scalar matrix for some positive integer m. We show that a function of U can be realized on a quantum computer with at most O(mK+m^2log m) elementary gates. The functions of U are realized by a generic quantum circuit, which has a particularly simple structure. Among other results, we obtain efficient circuits for the fractional Fourier transform.Comment: 4 pages, 2 figure
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