نتایج جستجو برای: soil attenuation

تعداد نتایج: 229138  

ژورنال: فیزیک زمین و فضا 2015

New attenuation relationships for rock and soil in Alborz, have been developed in this study. When the quantity of usable ground-motion data is inadequate in the magnitude and distance ranges, development of an empirical prediction equation is deficient. Due to lack of data, the two well-known simulation techniques, point source and finite-fault models have been used to generate more than ten t...

The diagnostic accuracy of single photon emission computed tomography (SPECT) is profoundly influenced by attenuation phenomenon. Soft tissue attenuation degrades cardiac SPECT image quality, thereby decreasing the possibility of the detection of the lesions. A variety of correction techniques based on different assumptions have been used to reduce the impact of attenuation. Several types of sy...

2015
Rebecka Törnqvist Jerker Jarsjö Josefin Thorslund P. Suresh C. Rao Nandita B. Basu Georgia Destouni

Irrigated agriculture can modify the cycling and transport of nitrogen (N), due to associated water diversions, water losses, and changes in transport flow-paths. We investigate dominant processes behind observed long-term changes in dissolved inorganic nitrogen (DIN) concentrations and loads of the extensive (465,000 km2) semi-arid Amu Darya River basin (ADRB) in Central Asia. We specifically ...

2006
S. R. Drescher M. K. Burke A. J. Lewitus S. D Brown

Urbanization is escalating in many coastal areas of the US and is associated with deteriorating water quality. Often the associated changes in land use result in an overabundance of nutrients and other types of pollution entering ground and surface waters. It is important that we understand biogeochemical transformation processes on urbanizing watersheds if we are to develop management practice...

2013
Nil Kucuk Zeynal Tumsavas Merve Cakir

The mass attenuation coefficients (μs) for five different soil samples were measured at 661.6, 1173.2 and 1332.5 keV photon energies. The soil samples were separately irradiated with (137)Cs and (60)Co (370 kBq) radioactive point gamma sources. The measurements were made by performing transmission experiments with a 2″ × 2″ NaI(Tl) scintillation detector, which had an energy resolution of 7% at...

Journal: :Remote Sensing 2015
Ju Hyoung Lee Jungho Im

Bias correction is a very important pre-processing step in satellite data assimilation analysis, as data assimilation itself cannot circumvent satellite biases. We introduce a retrieval algorithm-specific and spatially heterogeneous Instantaneous Field of View (IFOV) bias correction method for Soil Moisture and Ocean Salinity (SMOS) soil moisture. To the best of our knowledge, this is the first...

Journal: :iranian journal of nuclear medicine 2014
mahsa noori asl alireza sadremomtaz

the diagnostic accuracy of single photon emission computed tomography (spect) is profoundly influenced by attenuation phenomenon. soft tissue attenuation degrades cardiac spect image quality, thereby decreasing the possibility of the detection of the lesions. a variety of correction techniques based on different assumptions have been used to reduce the impact of attenuation. several types of sy...

2002
TSAN MO THOMAS J. SCHMUGGE THOMAS J. JACKSON

A model for sim~ating the measured radar backscattering coefficient of vegetation-covered soil surfaces is presented in this study. The model consists of two parts: the first is a soft surface model to describe the backscattered radar pulses from a rough soil surface, and the second part takes into account the effect of vegetation cover. The soil surface is characterized by two parameters, the ...

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