نتایج جستجو برای: si

تعداد نتایج: 74952  

Farrokh Roya Nikmaram Khadijeh Kalateh Pegah Kanganizadeh

In this work, the radial distribution function (RDF) of H2 adsorption on coronene (C24) and its Si Substituted forms was investigated by Monte Carlo method. The effect of number and position of silicon substituent on the Coronene (C24) was compared. The maximum value of RDF at 298 K and 0.1 MPa is 4.34 for 18 Si, A structure at 0.73 Å. On the basis of results, t...

Journal: :iranian journal of medical physics 0
mahmood nazarpoor department of radiology, faculty of paramedicine, tabriz university of medical sciences, tabriz, iran

introduction contrast-enhanced fluid-attenuated inversion recovery (flair) is one of the mri sequences that can be used for detection and evaluation of pathological changes in the brain. in this work, we have studied the effect of different echo times (te) on the maximum relationship between signal intensity and concentration of the contrast agent using the flair sequence. materials and methods...

2009
Giorgio Ragusa

Dato un insieme A di n elementi, si chiamano disposizioni di classe k i suoi sottoinsiemi ordinati di k elementi. Se si ammette che gli elementi possano anche ripetersi si parla di disposizioni con ripetizione, altrimenti di disposizioni semplici. Le disposizioni semplici aventi n = k si chiamano permutazioni semplici. Si chiama permutazione con ripetizione una permutazione di n elementi non tu...

2003
Eun-Chel Cho Dengyuan Song James Xia Armin G. Aberle Martin A. Green

In this study, we made the heterojunction solar cells on Si substrate by fabricating a nanocrystalline Si/SiO2 superlattice emitter structure. Amorphous silicon and silicon dioxide superlattice were prepared by rf Si sputtering and plasma oxidation, respectively. The deposited amorphous silicon was crystallized at high temperature. Microstructure studies by TEM show that amorphous silicon was c...

1999
I. Goldfarb

Although epitaxial growth has been traditionally monitored by reciprocal space techniques, such as reflection highenergy electron diffraction (RHEED), the development of surface-sensitive imaging techniques, such as scanning tunneling microscopy (STM), allows for monitoring in the real-space. RHEED averages information over relatively large sample regions, and is thus more representative of the...

Journal: :Physical chemistry chemical physics : PCCP 2011
Sung Chul Jung Young-Kyu Han

Fast Li transport in battery electrodes is essential to meeting the demanding requirements for a high-rate capability anode. We studied the intercalation of a Li atom into the surface and subsurface layers of Si(100) and Si(111) using density functional calculations with a slab representation of the surfaces. We suggest that the Li atom migrates on the Si surfaces and is subsequently inserted i...

1999
M. L. Brongersma A. Polman H. A. Atwater Thomas J. Watson

Depth-resolved measurements of the photoluminescence of Si implanted and annealed SiO2 films on Si have been performed to determine the depth distribution of luminescent Si nanocrystals. Si nanocrystals with diameters ranging from ;2 to 5 nm were formed by implantation of 35 keV Si ions into a 110-nm-thick thermally grown SiO2 film on Si~100! at a fluence of 6310 16 Si/cm, followed by a thermal...

2016
Trine Madsen Bregje van Spijker Karen-Inge Karstoft Merete Nordentoft Ad Jfm Kerkhof

BACKGROUND Suicidal ideation (SI) is a common mental health problem. Variability in intensity of SI over time has been linked to suicidal behavior, yet little is known about the temporal course of SI. OBJECTIVE The primary aim was to identify prototypical trajectories of SI in the general population and, secondarily, to examine whether receiving Web-based self-help for SI, psychiatric symptom...

2014
Malcolm G. Keeping R. Stuart Rutherford C. Sewpersad Neil Miles

Silicon (Si) is important in mitigating abiotic and biotic plant stresses, yet many agricultural soils, such as those of the rainfed production areas of the South African sugar industry, are deficient in plant-available Si, making Si supplementation necessary. However, Si uptake by sugarcane (Saccharum spp. hybrids) is limited even where silicate amendments improve soil Si status. Rhizosphere p...

2005
T. P. Chen

In this study, the analysis of the XPS Si 2p peaks shows the existence of the five chemical structures corresponding to the Si oxidation states Si n+ (n =0, 1, 2, 3, and 4) in Si-implanted SiO2 films, and the concentration of each oxidation states is determined quantitatively. The evolution of the five Si oxidation states as a function of thermal annealing is studied. On the other hand, Si 2p c...

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