نتایج جستجو برای: soil attenuation
تعداد نتایج: 229138 فیلتر نتایج به سال:
Root system interactions and competition for resources are active areas of research that contribute to our understanding of how roots perceive and react to environmental conditions. Recent research has shown this complex suite of processes can now be observed in a natural environment (i.e. soil) through the use of X-ray microcomputed tomography (μCT), which allows non-destructive analysis of pl...
Abiotic reductive dechlorination of chlorinated ethylenes by soil in anaerobic environments was characterized to improve knowledge of the behavior of chlorinated ethylenes in natural systems, including systems modified to promote attenuation of contaminants. Target organics in the soil suspension reached sorption equilibrium in 2 days and the sorption isotherm of target organics was properly de...
As potent allelochemicals, phenolic acids are believed to be associated with replanting disease and cause microflora shift and structural disorder in the rhizosphere soil of continuously monocultured Radix pseudostellariae. The transcriptome sequencing was used to reveal the mechanisms underlying the differential response of pathogenic bacterium Kosakonia sacchari and beneficial bacterium Bacil...
The effects of a heavy travelling load on the soil medium and on the adjacent structures were studied. Five soil profiles were analyzed, three from sites in Southern California and two from well documented sites in Europe. It was found that the material damping in the soil layers does not affect attenuation, but rather radiation damping is the most significant. Four of the Five soil profiles st...
درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...
Attenuation relationships that are used to characterize estimated ground motion often ignore details of the earth’s highly-variable three-dimensional velocity and attenuation structure. Increasingly available attenuation models can be used to refine the expected ground motions. First, some tests are performed to look at the effect of the variability in several parameters, such as crustal attenu...
SPECT detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. Attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. In our study efficacy of Chang method was evaluated for attenuation purpose, using a custom made heart phantom. Due to d...
Introduction: Attenuation correction is a useful process for improving myocardial perfusion SPECT and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). Attenuation artifacts are a common problem in myocardial perfusion SPECT. The aim of this study was to compare the effect of attenuation correction using different a...
For detecting water pipeline leakage signals, in the past people preferred to use sensors obtain signal and then various means methods remove noise increase positioning accuracy. However, as is generated, it spreads along wrapped soil. In this process, will change significantly, eventually becoming very different from original signal. As such, detection accuracy decline, distance becomes longer...
Acoustic waves can be a viable tool for the detection and identification of land mines, unexplored ordnance (UXO), and other buried objects. Design of acoustic instruments and interpretation and processing of acoustic measurements call for accurate numerical models to simulate acoustic wave propagation in a heterogeneous soil with buried objects. Compared with the traditional seismic exploratio...
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