نتایج جستجو برای: spectral indices
تعداد نتایج: 243566 فیلتر نتایج به سال:
This paper provides a methodology to quantify the interrelationship between the seismic intensity parameters and the structural damage. First, a computer-supported elaboration of the accelerograms provides several peak, spectral and energy seismic parameters. After that, nonlinear dynamic analyses are carried out to provide the structural response for a set of seismic excitations. Among the sev...
We explored simple and useful spectral indices for estimating photosynthetic variables (radiation use efficiency and photosynthetic capacity) at a canopy scale based on seasonal measurements of hyperspectral reflectance, ecosystem CO2 flux, and plant and micrometeorological variables. An experimental study was conducted over the simple and homogenous ecosystem of an irrigated rice field. Photos...
soil salinity has been a large problem in arid and semi arid regions. preparation of such maps is useful for natural resource managers. old methods of preparing such maps require a lot of time and cost. multi-spectral remotely sensed dates due to the broad vision and repeating of these imageries is suitable for provide saline soil maps. this investigation is conducted to provide saline soil map...
Assessing nitrogen (N) status is important from economic and environmental standpoints. To date, many spectral indices to estimate cotton chlorophyll or N content have been purely developed using statistical analysis approach where they are often subject to site-specific problems. This study describes and tests a novel method of utilizing physical characteristics of N-fertilized cotton and comb...
Key Words: GALAXIES: ABUNDANCES – GALAXIES: EVOLUTION – GALAXIESL SPIRAL – GALAXIES: STELLAR CONTENT
We study the old problem of the uniqueness of chemical evolution models. We showed in Mollá et al. (1999) that multiphase models for three Virgo cluster galaxies were able to reproduce the observed radial distributions of spectral indices Mg2 and Fe52. But those models may fit the present-epoch radial distributions with different star formation histories (Tosi 1996). The two spectral indices ab...
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