نتایج جستجو برای: pre ionization

تعداد نتایج: 349227  

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - دانشکده زبانهای خارجی 1389

abstract this study examines the effect of teaching lexical inferencing strategies on developing reading comprehension skill of iranian advanced efl learners. participants were female students of meraj and shokouh institudes of garmsar a quasi-experimental design using two intact advanced classes of efl students at meraj and shokouh institutes. as the first step, a general toefl proficiency te...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد شاهرود - دانشکده علوم انسانی 1393

the present study was conducted to investigate the role of summary in teaching grammar process on pre-university students. to this end, 48 male pre-university students in semnan were participants. they were math class that we called experimental group and science class as control group. in order to make sure there was no significant difference in proficiency level of two groups. a pre-test wa...

Journal: :Journal of chromatography. A 2006
A Agüera M Mezcua F Mocholí A Vargas-Berenguel A R Fernández-Alba

Hybrid chemical ionization (HCI), a new and useful alternative to conventional chemical ionization mass spectrometry, has been applied to the analysis of the pharmaceutical diclofenac in wastewater samples. This technique takes advantage of the high versatility of ion trap (IT) spectrometers combined with external ionization sources. In hybrid configuration, reagent ions are generated in the ex...

2014
C Köhn

Ionization showers are created in the Earth’s atmosphere by cosmic particles or by run-away electrons from pulsed discharges or by the decay of radioactive elements like radon and krypton. These showers provide pre-ionization that can play a role for discharge inception or evolution; radioactive admixtures in plasma technology use the same effect. While the CORSIKA program provides cross sectio...

2016
Xi Chu Gerrit C. Groenenboom

Using a time-dependent density-functional-theory (TDDFT) method that incorporates the exact exchange, we reproduce the measured ionization suppression for vanadium in 1500-nm lasers of 1.4 to 2.8 × 1013 W/cm2. The calculated ionization yields are 0.07 to 0.5 in 100 fs sin2 pulses. For weaker laser intensities a method with more configurations is needed to properly describe the multiphoton, rath...

Journal: :J. Sci. Comput. 2010
Antoine Bourgeade Candice Mézel Olivier Saut

In this paper, we present a model for propagation of intense and ultrashort laser pulses ionizing dielectrics. We consider early ionization so that this process is sufficiently weak to avoid requiring a complete description of the ionization process (e.g. the use of kinetic equations which are very expensive from a computational point of view). As the intensity of the field is small, one photon...

Mohammad Bahrami Mohammad Taghi Bahreyni Toossi,

Introduction Computed Tomography scans are a very important tool for diagnosis and assessment of response to treatment in the practice of medicine. Ionizing radiation in medical imaging is undoubtedly one of the most powerful diagnostic tools in medicine. Yet, as with all medical interventions, there are potential risks in addition to the clear potential benefits. Materials and Methods Two refe...

2002
Hiroyuki Shimada Yoichi Nakai Hitoshi Oyama Kozo Ando Tadashi Kambara Yasunori Yamazaki

Recent progress in femtosecond (fs) tera-watt (TW) laser development has raised a new fundamental question in atomic and molecular physics, i.e., how atoms and molecules react against an intense electromagnetic field. As is well known, an atom exposed to photons of relatively low flux density is ionized only if the photon energy exceeds the ionization potential of the atom. On the other hand, w...

2006
V. N. Fedosseev

At the ISOLDE on-line isotope separation facility, the resonance ionization laser ion source (RILIS) can be used to ionize reaction products as they effuse from the target. The RILIS process of laser step-wise resonance ionization of atoms in a hot metal cavity provides a highly element selective stage in the preparation of the radioactive ion beam. As a result, the ISOLDE mass separators can p...

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