نتایج جستجو برای: rays

تعداد نتایج: 44458  

Journal: :journal of sciences islamic republic of iran 0

a more detailed analysis is made of the energy spectrum of the diffuse component of extragalactic gamma rays over the range of 0.3- 10 gev, obtained fromthe egret instrument at the compton gamma ray observatory. the derived excess energy spectrum of high galactic latitude, b > 60°, using intercept method shows that it is correlated with virgo cluster (over lsr) and average virgo intensity is ab...

1997
Andrew W. Strong Igor V. Moskalenko

An extensive program for the calculation of galactic cosmic-ray propagation has been developed. This is a continuation of the work described in [1]. The main motivation for developing this code [2] is the prediction of diffuse Galactic gamma rays for comparison with data from the cgro instruments egret, comptel, and osse. The basic spatial propagation mechanisms are (momentumdependent) diffusio...

2004
Igor V. Moskalenko

This paper presents an introduction to the astrophysics of cosmic rays and diffuse γ-rays and discusses some of the puzzles that have emerged recently due to more precise data and improved propagation models: the excesses in Galactic diffuse γ-ray emission, secondary antiprotons and positrons, and the flatter than expected gradient of cosmic rays in the Galaxy. These also involve the dark matte...

2007
Hiroyasu Tajima Tuneyoshi Kamae Stefano Finazzi Johann Cohen-Tanugi James Chiang

We describe the role of GeV gamma-ray observations with GLAST-LAT (Gamma-ray Large Area Space Telescope Large Area Telescope) in identifying interaction sites of cosmic-ray proton (or hadrons) with interstellar medium (ISM). We expect to detect gamma rays from neutral pion decays in high-density ISM regions in the Galaxy, Large Magellanic Cloud, and other satellite galaxies. These gamma-ray sou...

Journal: :Publications of the Astronomical Society of Australia 2010

Object: The gold standard for evaluating bone mineral density is dual energy x-ray absorptiometry (DEXA).  Prior studies have shown poor reliability using analog wrist X-rays in diagnosing osteoporosis. Our goal was to investigate if there was improved diagnostic value to visual assessment of digital hand X-rays in osteoporosis screening. We hypothesized that similar to analog counterparts, dig...

Journal: :Journal of radiation research 1991
O Yamamoto T Jo M Sugiyama T Itoh

Radioresistant E. coli TGl harboring pUC 18 plasmid which was Ampicillin-resistant was exposed to 60Co gamma-rays or 3H beta-rays in saline to determine whether the relative biological effectiveness of 3H beta-rays is higher than one. After exposure to 60Co gamma-rays at a dose rate of 0.465 Gy/min, the D0 by colony formation was 145 Gy in the presence of Ampicillin in or absence from the agar ...

Journal: :Journal of the Franklin Institute 1896

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