نتایج جستجو برای: epithermal process

تعداد نتایج: 1312995  

2005
T. D. Ullrich

Porphyry Cu and epithermal deposits are spatially and temporally related to specific volcanic and plutonic rocks emplaced during the formation of long-lived magmatic arcs formed along convergent plate boundaries (e.g., Sillitoe, 1972; Sutherland Brown, 1976; Titley, 1982; Sawkins, 1990; Bissig et al., 2003). Recognizing the presence, types of deposits, and age of the mineralized volcanoplutonic...

Journal: :iranian journal of radiation research 0
j.g. fantidis department of electrical engineering, technological education institute of eastern macedonia and thrace, saint loucas, kavala, greece a. antoniadis cardiovascular division, brigham and women's hospital, harvard medical school, boston, usa

background: a boron neutron capture therapy (bnct) facility, based on a dt neutron generator, with the final goal to find out a potential, alternative, solution to existing bnct treatment facilities which are based on nuclear reactors is examined. materials and methods: with the aim of the mcnp4b monte carlo code different beam-shaping assembly (bsa) configurations were considered. lead was sel...

Journal: :Radiation research 1992
C S Wuu H I Amols P Kliauga L E Reinstein S Saraf

Preclinical studies for boron neutron capture therapy (BNCT) using epithermal neutrons are ongoing at several laboratories. The absorbed dose in tumor cells is a function of the thermal neutron flux at depth, the microscopic boron concentration, and the size of the cell. Dosimetry is therefore complicated by the admixture of thermal, epithermal, and fast neutrons, plus gamma rays, and the array...

2000
M. J. McCall

Over the past decade, there has been a continued interest in the development of Boron Neutron Capture Therapy (BNCT) as a potential treatment for cancerous tumours and especially certain brain tumours. In this method, advantage is taken of the nuclear properties of certain elements such as boron. A special boron carrier drug, designed to be selectively taken up by the cancer cells, is administe...

1999
M. A. BUSTILLO J. GARCIA J. MARTINEZ - FRIAS A. DELGADO

Unusual mineralized and silicified carbonate-rich geodes were found hosted in Lower Triassic red mudstones in Central Spain. From their borders to their centres, the geodes display (a) a millimetric carbonate crust, (b) a quartz rim, (c) massive dolomite, (d) gold-bearing iron-rich infills (hematite laths and goethite with up to 7000 ppm of gold) and (e) calcite cements that sometimes seal the ...

Journal: :Medical physics 1995
S A Wallace J N Mathur B J Allen

Neutron penetration in tissue is a major limitation of thermal NCT, as such much work has centered upon the epithermal neutron beam in an effort to improve this situation. Further gains in neutron flux penetration, and thus therapeutic ratios, are possible if natural water is replaced with heavy water prior to therapy. Applying MCNP to a heterogeneous ellipsoidal skull/brain model, advantage de...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم پایه 1388

چکیده ندارد.

2012
James A. Saunders

Tertiary low sulfidation (LS) epithermal deposits in the western USA often show evidence of the former presence of nanoparticle-sized precious-metal and silica phases in the highest grade (bonanza) ores. Here, nanoparticles are defined to have a size less than ~10 m. The ore-mineral textures that formed from aggregation of nanoparticles (or colloids) observed to date in these ores include elect...

2002
James R. Clark A. E. Williams-Jones

This report presents three new potassium-argon isotopic age determinations of minerals associated with epithermal alteration from the Toodoggone district, north-central British Columbia. The Toodoggone area has received extensive exploration attention over the past 10 years. In addition to a former goldsilver producer (Baker mine), the district contains a major new gold-silver mine in developme...

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