نتایج جستجو برای: x ray spectrum

تعداد نتایج: 865194  

Journal: :journal of paramedical sciences 0
mojtaba navvabpour department of radiation technology paramedical sciences faculty, shahid beheshti university of medical sciences, tehran, iran mohammad navvabpour material engineering faculty, tehran university, tehran, iran mohammad ghane-e dehkordi medical radiation sciences faculty , shahid beheshti university of medical sciences, tehran, iran hossein nazari moghadam radiation technalogy sciences faculty , radiation technology department paramedical sciences , shahid beheshti university of medical sciences, tehran, iran seyed mohammad reza aazami department of radiation technology, 5 department of radiation technology,paramedical sciences faculty, shahid beheshti university of medical sciences, tehran, iran

the output of x-ray, especially in the field of required energy for diagnosing the disease is very low (in diagnosing lamps, it is less than 1%). in this kind of lamps the rest of the electrical energy is transformed to heat. this considerable amount of heat induces a myriad of too many limitations in choosing higher levels of radiation, particularly in specialized techniques. this process is t...

2015
L. Miaja-Avila G. C. O'Neil J. Uhlig C. L. Cromer M. L. Dowell R. Jimenez A. S. Hoover K. L. Silverman J. N. Ullom

We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x...

2003
D. M. Worrall M. J. Hardcastle T. J. Pearson A. C. S. Readhead

We combine results from ROSAT, Chandra, and multifrequency VLBA observations of the Compact Steep Spectrum quasar 3C 48 in an attempt to understand why the radio source is so small and unusual. The X-ray spectrum shows no evidence for the excess absorption which might have allowed us to conclude that 3C 48 is small because it is bottled up by cold neutral gas. We infer that the X-ray spectrum o...

Journal: :iranian journal of radiation research 0
v. changizi department of medical physics, faculty of medicine, tehran university of medical sciences, tehran, iran m.a. oghabian department of medical physics, faculty of medicine, tehran university of medical sciences, tehran, iran s. sarkar department of medical physics, faculty of medicine, tehran university of medical sciences, tehran, iran r.d. speller department of medical physics and bioengineering, university college london, london wc1e 6ja, uk a. arab kheradmand department of medical physics, faculty of medicine, tehran university of medical sciences, tehran, iran

abstract background: coherent scattering leads to diffraction effects and especially constructive interferences. theseinterferences carry some information about the molecular structure of the tissue. as breast cancer isthe most widespread cancer in women, this project evaluated the application of small anglex-ray scattering (saxs) for differentiation between normal and cancerous breast tissues....

2008
G. J. M. Luna J. L. Sokoloski

We describe Chandra High-Energy Transmission Grating Spectrometer observations of RT Cru, the first of a new sub-class of symbiotic stars that appear to contain white dwarfs (WDs) capable of producing hard X-ray emission out to greater than 50 keV. The production of such hard X-ray emission from the objects in this sub-class (which also includes CD −57 3057, T CrB, and CH Cyg) challenges our un...

1996
D. Grupe K. Beuermann H. - C. Thomas K. Mannheim H. H. Fink

We present results of an infrared-to-X-ray study of 76 bright soft X-ray selected Seyfert galaxies discovered in the ROSAT All-Sky Survey. These objects are characterized by steep X-ray spectra in the 0.2-2.0 keV bandpass with power law energy spectral indices in the range of 1.3 to 8 and a lack of internal absorption by neutral hydrogen. Our sample selection based on hardness ratio yields a me...

Journal: :international journal of nanoscience and nanotechnology 2015
m. mirzaei h. ahadi m. shariaty-niassar m. akbari

in this research fe-tio2 nanocomposites with different molar ratios of fe/ti were prepared as nano-photocatalyst using a modified sol-gel process at ambient temperature. crystallographic properties of nanocomposites were characterized by x-ray diffraction (xrd). surface morphology and mean particle size of nanocomposites were specified by field emission scanning electron microscopy (fesem) and ...

2009
Haimin Wang

We revisit the flare on 1992 January 13, which is now universally termed the “Masuda flare”. Our work is motivated by the remarkable improvement of Yohkoh hard X-ray imaging, which was only achieved after the intensive investigations on this famous event. With the calibrated Hard X-ray Telescope (HXT) data, we find that the hard X-ray coronal source is indeed a loop-top source, located slightly...

1997
A. Maggio F. Favata G. Peres

We present an X-ray observation of the active giant β Cet, performedwith the LowEnergy Concentrator Spectrometer (LECS) on-board the SAX satellite. The resulting X-ray spectrum is well fit by an optically-thin plasma model with two discrete temperatures, and the inferred coronal metallicity is compatible both with the abundances derived from a re-analysis of the ASCA SIS spectrum of the same ob...

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