486 research outputs found

    A study of the absorption coefficient of silicon in the wave length region between .5 and 1.1 microns Final report

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    Solar cell performance prediction from absorption coefficients of silicon in wavelengths from 0.5 to 1 micron as functions of doping levels and crystal damag

    The study of the epitaxial parameters on reliability of silicon planar devices technical summary report, 25 jun. 1964 - 25 jun. 1965

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    Effect of varying epitaxial deposition parameters on reliability of silicon planar solid state device

    Effects of Intensive Training on Prolactin Responses to Submaximal Exercise in Males

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    The purpose of this study was to determine if serum prolactin responses to submaximal exercise were affected by 8 weeks of intensive training (5 cl/wk, 90 min/d 65-200% V02max). Nine males performed 90 minute continuous exercise bouts (cycle ergometry; 65% V02 max) at the end of 1, 4, and 8 weeks of training. Blood samples were obtained pre-training, and pre-, post-exercise. Significant differences were not seen in pre- and post-exercise prolactin levels at weeks 1 and 4. However, at week 8 the post-exercise prolatin was significantly greater than the pre-exercise levels (6.8 ± 0.9 vs 3.8 ± 1.0 ng·ml-1; P-1, respectively). The findings suggest intensive training results in a relative augmentation of the post-exercise prolactin response; however, this effect seems to be due primarily to the training induced lowered resting prolactin levels

    High resolution CMB power spectrum from the complete ACBAR data set

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    In this paper, we present results from the complete set of cosmic microwave background (CMB) radiation temperature anisotropy observations made with the Arcminute Cosmology Bolometer Array Receiver (ACBAR) operating at 150 GHz. We include new data from the final 2005 observing season, expanding the number of detector-hours by 210% and the sky coverage by 490% over that used for the previous ACBAR release. As a result, the band-power uncertainties have been reduced by more than a factor of two on angular scales encompassing the third to fifth acoustic peaks as well as the damping tail of the CMB power spectrum. The calibration uncertainty has been reduced from 6% to 2.1% in temperature through a direct comparison of the CMB anisotropy measured by ACBAR with that of the dipole-calibrated WMAP5 experiment. The measured power spectrum is consistent with a spatially flat, LambdaCDM cosmological model. We include the effects of weak lensing in the power spectrum model computations and find that this significantly improves the fits of the models to the combined ACBAR+WMAP5 power spectrum. The preferred strength of the lensing is consistent with theoretical expectations. On fine angular scales, there is weak evidence (1.1 sigma) for excess power above the level expected from primary anisotropies. We expect any excess power to be dominated by the combination of emission from dusty protogalaxies and the Sunyaev-Zel'dovich effect (SZE). However, the excess observed by ACBAR is significantly smaller than the excess power at ell > 2000 reported by the CBI experiment operating at 30 GHz. Therefore, while it is unlikely that the CBI excess has a primordial origin; the combined ACBAR and CBI results are consistent with the source of the CBI excess being either the SZE or radio source contamination.Comment: Submitted to ApJ; Changed to apply a WMAP5-based calibration. The cosmological parameter estimation has been updated to include WMAP

    National, Regional, and State Abusive Head Trauma: Application of the CDC Algorithm

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    To examine national, regional, and state abusive head trauma (AHT) trends using child hospital discharge data by applying a new coding algorithm developed by the Centers for Disease Control and Prevention (CDC)

    Spider Optimization: Probing the Systematics of a Large Scale B-Mode Experiment

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    Spider is a long-duration, balloon-borne polarimeter designed to measure large scale Cosmic Microwave Background (CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky with degree angular resolution in I, Q and U Stokes parameters, in four frequency bands from 96 to 275 GHz. Spider's ultimate goal is to detect the primordial gravity wave signal imprinted on the CMB B-mode polarization. One of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects. This paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity. This is done by injecting realistic-amplitude, time-varying systematics in a set of simulated time-streams. Tests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets, beam systematics and receiver gain drifts are shown. Spider's default observing strategy is to spin continuously in azimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola and a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, results shown here indicate that either mode of operation can be used by Spider.Comment: 15 pages, 12 figs, version with full resolution figs available here http://www.astro.caltech.edu/~lgg/spider_front.ht

    ACBAR: The Arcminute Cosmology Bolometer Array Receiver

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    We describe the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver designed for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich effect in clusters of galaxies. The ACBAR focal plane consists of a 16-pixel, background-limited, 240 mK bolometer array that can be configured to observe simultaneously at 150, 220, 280, and 350 GHz. With 4-5' FWHM Gaussian beam sizes and a 3 degree azimuth chop, ACBAR is sensitive to a wide range of angular scales. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001. We describe the design of the instrument and its performance during the 2001 and 2002 observing seasons.Comment: 59 pages, 16 figures -- updated to reflect version published in ApJ

    The BICEP2 CMB polarization experiment

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    The Bicep2 telescope is designed to measure the polarization of the cosmic microwave background on angular scales near 2-4 degrees, near the expected peak of the B-mode polarization signal induced by primordial gravitational waves from inflation. Bicep2 follows the success of Bicep, which has set the most sensitive current limits on B-modes on 2-4 degree scales. The experiment adopts a new detector design in which beam-defining slot antennas are coupled to TES detectors photolithographically patterned in the same silicon wafer, with multiplexing SQUID readout. Bicep2 takes advantage of this design's higher focal-plane packing density, ease of fabrication, and multiplexing readout to field more detectors than Bicep1, improving mapping speed by nearly a factor of 10. Bicep2 was deployed to the South Pole in November 2009 with 500 polarization-sensitive detectors at 150 GHz, and is funded for two seasons of observation. The first months' data demonstrate the performance of the Caltech/JPL antenna-coupled TES arrays, and two years of observation with Bicep2 will achieve unprecedented sensitivity to B-modes on degree angular scales

    QUaD: A High-Resolution Cosmic Microwave Background Polarimeter

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    We describe the QUaD experiment, a millimeter-wavelength polarimeter designed to observe the Cosmic Microwave Background (CMB) from a site at the South Pole. The experiment comprises a 2.64 m Cassegrain telescope equipped with a cryogenically cooled receiver containing an array of 62 polarization-sensitive bolometers. The focal plane contains pixels at two different frequency bands, 100 GHz and 150 GHz, with angular resolutions of 5 arcmin and 3.5 arcmin, respectively. The high angular resolution allows observation of CMB temperature and polarization anisotropies over a wide range of scales. The instrument commenced operation in early 2005 and collected science data during three successive Austral winter seasons of observation.Comment: 23 pages, author list and text updated to reflect published versio

    SPIDER: a balloon-borne CMB polarimeter for large angular scales

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    We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. Spider's first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map \sim8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The Spider mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.Comment: 12 pages, 6 figures; as published in the conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010
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