نتایج جستجو برای: natural background radiation

تعداد نتایج: 1502475  

Journal: :Optics letters 2004
S A Derevyanko S K Turitsyn

We examine reduction of phase jitter by use of in-line Butterworth filters in soliton systems in the context of differential phase-shift-keying coding. We also demonstrate numerically that the use of a Butterworth filter in a return-to-zero differential phase-shift-keying system can reduce continuum background radiation.

2003
R. C. Henry

Observation of faint diffuse ultraviolet background radiation is a delicate undertaking, given the brightness of the ultraviolet stars against which discrimination is essential. I demonstrate that the technique of tomography is unsuited to this particular task.

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2001
P Catravas S Chattopadhyay E Esarey W P Leemans R Assmann F J Decker M J Hogan R Iverson R H Siemann D Walz D Whittum B Blue C Clayton C Joshi K A Marsh W B Mori S Wang T Katsouleas S Lee P Muggli

Emissions produced or initiated by a 30-GeV electron beam propagating through a approximately 1-m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity ...

2000
N. P. S. Sidhu Alkis Rouvas Patrick Cadman

The use of a radioactive check device containing Strontium 90 was investigated to carry out the redundancy checks of Farmer-type ionization chambers. It was not possible to meet the recommended tolerance limits of the redundancy checks without taking into account the angular response of the ionization chambers. The ionization chambers exhibited a maximum variation of 1% in the angular response ...

2006
George Lazarides

The big bang model and the history of the early universe according to the grand unified theories are introduced. The shortcomings of big bang are discussed together with their resolution by inflationary cosmology. Inflation, the subsequent oscillation and decay of the inflaton, and the resulting ‘reheating’ of the universe are studied. The density perturbations produced by inflation and the tem...

2012
Richard Conn Henry Henry A. Rowland

I report on progress in my ongoing work with Professor Jayant Murthy concerning the origin and nature of the diffuse ultraviolet background radiation over the sky. We have obtained and are reducing a vast trove of Voyager ultraviolet spectrometer observations of the diffuse background shortward of Lα, including for the first time measurements made from the outermost regions of the solar system,...

Ali Akbar Salehi Kazem Naddafi Masud Yunesian Mohammad Reza Deevband, Mohammad Reza Kardan Molood Gooniband Shooshtari Nasrin Fathabadi, Ramin Nabizadeh Nodehi

Introduction: Human beings are naturally exposed to ionizing radiation in any environment. There are two main contributors to radiation exposures from natural sources: cosmic rays, Cosmo genic radionuclides, and radioactive nuclides that originated in the earth's crust. According to the latest data provided by the United Nations Scientific Committee on the Effects of Atomic Rad...

Journal: :iranian journal of allergy, asthma and immunology 0
massoud attar yaghob molaie kondolousy nemat khansari

iran is one of several countries that has regions of high dose natural ionizing radiation. two wellknown villages in the suburb of ramsar town in the caspian sea strip, taleshmahaleh and chaparsar, have background radiation that is 13 times higher than normal. this radiation is the result of radium 226 and radon gas both of which are highly water soluble. while people living in these regions do...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه کاشان - دانشکده علوم انسانی 1389

abstract poor reading comprehension can result in failure in using references, benefiting from professional gatherings and resources, keeping up with the growing body of knowledge in the virtual world of the internet, and failing to achieve in efl programs. the purpose of the present quasi-experimental study was to explore the effects of background knowledge and previewing narrative and expos...

Journal: :iranian journal of radiation research 0
m. gholami department of medical physics, faculty of medicine, lorestan university of medical sciences, khorram abad, iran s. mirzaei department of medical radiation engineering, faculty of technical and engineering, islamic azad university, science and research branch, tehran ,iran a. jomehzadeh department of medical physics, faculty of medicine, rafsanjan university of medical sciences, rafsanjan, iran

background: the exposure of human being to ionize radiation from natural sources is a continuing, inescapable feature of life on earth. direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. such investigations can be useful for assessment of public dose rates, the performance of epidemiological studies, and keeping refe...

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